In this paper, finite-time tracking problem of nonholonomic mobile robots for a moving target is considered. First of all, polar coordinates are used to characterize the distance and azimuth between the moving target and the robot. Then, based on the distance and azimuth transported from the sensor installed on the robot, a finite-time tracking control law is designed for the nonholonomic mobile robot by the switching control method. Rigorous proof shows that the tracking error converges to zero in (...) a finite time. Numerical simulation demonstrates the effectiveness of the proposed control method. (shrink)

Pick-and-roll is the most widespread cooperative action among high-level basketball teams and the most applied strategy by coaches to gain an advantage over the rival team. During pick-and-roll, opposing teams perform antagonistic actions based on goals that are expressed in offensive and defensive tactics. The aim of this study is to examine the approaches of high-level coaches on the offensive and defensive dynamics emerging in matches of a basketball elite team during an entire season of the Spanish Asociación de Clubes (...) de Baloncesto league. To this end, we used a mixed-methods approach based on systematic observation of verbatim transcripts of interviews conducted with six high-level coaches about the pick-and-roll dynamics that emerged in matches of the Unicaja Málaga team during an entire season of the ACB league. The observational design was nomothetic, punctual, and multidimensional. The choice of this methodology is justified since we developed an ad hoc indirect observation tool to evaluate the coaches’ perspective on this dynamic. Once the intra-observer reliability of the instrument was confirmed, we performed a polar coordinate analysis to identify the significant relationships between the coaches’ evaluations and the offensive and defensive pick-and-roll elements that supported such verbal behaviors. The results highlight the presence of various offensive and defensive aspects of pick-and-roll emerging in the Unicaja team that were significantly associated with positive and negative evaluations of the coaches. The interview confirms that coach 1 and his staff were less confident in options that pick-and-roll offer, which is also reflected in the record of screens made and simulated, than coach 3. This study shows that the application of mixed methods, by analysis of the polar coordinate of the coding carried out on responses of a systematized interview, has proven to be an effective strategy in obtaining relevant information on the expert knowledge of the elite coaches on the influence of pick-and-roll on tactical actions in basketball. (shrink)

The development of nineteenth-century geodetic measurement challenges the dominant coherentist account of measurement success. Coherentists argue that measurements of a quantity are epistemically successful if their numerical outcomes converge across varying contextual constraints. Aiming at numerical convergence, in turn, offers an operational aim for scientists to solve problems of coordination. Geodesists faced such a problem of coordination between two indicators of the earth’s ellipticity, which were both based on imperfect ellipsoid models. While not achieving numerical convergence, their measurements produced novel (...) data that grounded valuable theoretical hypotheses. Consequently, they ought to be regarded as epistemically successful. This insight warrants a dynamic revision of coherentism, allowing to judge the success of a metric based on both its coherence and fruitfulness. On that view, scientific measurement aims to coordinate theoretical definitions and produce novel data and theoretical insights. (shrink)

This article starts off with the observation that in certain cases, presuppositions triggered by an element inside a question nucleus may fail to project. In fact, in what looks like coordinated structures involving polar questions, presupposition projection patterns are exactly parallel to what is observed when the corresponding assertions are coordinated. The article further shows that these facts do not fall out straightforwardly from existing theories of polar questions, (apparent) coordinations of questions, and presupposition projection. It then proposes (...) a trivalent extension of inquisitive semantics such that the observed pattern can be understood in terms of existing theories of presupposition projection. The proposal has the following properties: (a) apparent coordinations of questions are indeed coordinations of questions, and (b) the semantic denotation of polar questions is asymmetric with respect to the “yes” and “no” answers. (shrink)

This paper is a response to Enguehard (Natural Language Semantics 29(4):527–578, 2021 ), who observes that presuppositions project in the same way from coordinations of declaratives and coordinations of polar questions, but existing mechanisms of projection from declaratives (e.g. Schlenker in Theoretical Linguistics 34(3):157–212, 2008, Semantics and Pragmatics 2:1–78, 2009 ) fail to scale to questions. His solution involves specifying a trivalent inquisitive semantics for (coordinations of) questions that bakes the various asymmetries of presupposition projection into the lexical entry (...) of conjunction/disjunction. However, we argue that such a move faces both theoretical and empirical issues. Instead, we show that the data can be handled without moving to such an asymmetric inquisitive denotation, by adapting the novel pragmatic theory of _Limited Symmetry_ (Kalomoiros in Proceedings of the 52nd annual meeting of the North East linguistic society, GLSA, Amherst, 2022 ) to an inquisitive framework in a way that leaves the underlying semantics for conjunction symmetric and bivalent, while deriving the projection data. (shrink)

The mechanisms by which cells become polarised in the plane of an epithelium have been studied in Drosophila for many years. Work has focussed on two key questions: firstly, how individual cells adopt a defined polarity, and secondly how the polarity of each cell within a tissue is aligned with its neighbours. It has been established that asymmetric subcellular localisation of a number of polarity proteins is an essential mechanism underlying polarisation of single cells. The process by which this polarity (...) is coordinated between cells however is less well understood, but is thought to involve gradients of activity of the atypical cadherins Dachsous and Fat. Subsequently, this long‐range polarity signal is refined by local cell–cell interactions involving the transmembrane molecules Frizzled, Strabismus and Flamingo. The role of these factors in coordinating polarity will be discussed. BioEssays 27:1218–1227, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

We approach the semantics of prepositions from the perspective of conceptual spaces. Focusing on purely spatial locative and directional prepositions, we analyze both types of prepositions in terms of polar coordinates instead of Cartesian coordinates. This makes it possible to demonstrate that the property of convexity holds quite generally in the domain of prepositions of location and direction, supporting the important role that this property plays in conceptual spaces.

Planar cell polarity, the polarization of cells within the plane of the epithelium, orthogonal to the apical‐basal axis, is essential for a growing list of developmental events, and – over the last 15 years – has evolved from a little‐studied curiosity in Drosophila to the subject of a substantial research enterprise. In that time, it has been recognized that two molecular systems are responsible for polarization of most tissues: Both the “core” Frizzled system and the “global” Fat/Dachsous/Four‐jointed system produce molecular (...) asymmetry within cells, and contribute to morphological polarization. In this review, we discuss recent findings on the molecular mechanism that links “global” directional signals with local coordinated polarity. (shrink)

From the known coordinate representation of these operators, a unified treatment of the abstract operators for curvilinear coordinates and their canonically conjugate momenta is given for systems in three dimensions. A configuration representation, corresponding to classical configuration space, exists in which description is simplified; the three-dimensional ket space factors into a direct product of one-dimensional spaces. Four cases are examined, according to the range of the continuous curvilinear coordinate. In addition to normalization of momentum eigenstates to the Kronecker delta (...) for finite range of coordinate and normalization to the Dirac delta for range on the entire real axis, normalization occurs to δ (or δ+) for range on the positive (or negative) part of the real axis. The domain of Hermiticity of curvilinear coordinate and conjugate momentum operators in each case is the entire three-dimension ket space. The fundamental commutation relations hold in all representations. Statements to the contrary for the radial and azimuth coordinates in spherical polar coordinates are seen to be erroneous. (shrink)

Recent studies of gene expression in the developing fruitfly leg support a model – Meinhardt's Boundary Model – which seems to contradict the prevailing paradigm for pattern formation in the imaginal discs of Drosophila – the Polar Coordinate Model. Reasoning from geometric first principles, this article examines the strengths and weaknesses of these hypotheses, plus some baffling phenomena that neither model can comfortably explain. The deeper question at issue is: how does the fly's genome encode the three‐dimensional anatomy of (...) the adult? Does it demarcate territories and boundaries (as in a geopolitical map) and then use those boundaries and their points of intersection as a scaffolding on which to erect the anatomy (the Boundary Model)? Or does it assign cellular fates within a relatively seamless coordinate system (the Polar Coordinate Model)? The existence of hybrid Cartesian‐polar models shows that the alternatives may not be so clear‐cut: a single organ might utilize different systems that are spatially superimposed or temporally sequential. (shrink)

This review is focused on recent advances in our understanding of the development of coordinated cell polarity, through experiments on the Drosophila compound eye. Each eye facet (or “ommatidium”) contains a set of eight photoreceptor cells, placed so that their rhabdomeres form an asymmetric trapezoid. The array of ommatidia is organized so that these trapezoids are aligned in two mirror-image fields, dorsal and ventral to the eye midline (or “equator”). The development of this pattern depends on two systems of positional (...) information that inform the cluster of cells that will form an ommatidium of anterior/posterior (a/p) and dorsal/ventral (d/v) direction. The former (a/p) is encoded by a progressive wave of development (the morphogenetic furrow). The latter (d/v) involves molecules known to act in tissue polarity in other organs and organisms. Our understanding of the function of these molecules rests not only on their mutant phenotypes, biochemistry, and expression patterns, but also on the spatial effects when mutant patches of cells are made (genetic mosaics). BioEssays 21:275–285, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

Molecular and developmental studies of limb pattern formation have recently gained widespread attention. The fact that vertebrate limbs are amenable to both genetic and embryological manipulations has established this model system as a valuable paradigm for studying vertebrate development. Limb buds are polarised along all three major axes and the establishment of the dorso‐ventral (DV) polarity is dependent upon cues localised in the trunk, where a DV ectodermal interface is produced by confrontation of dorsal and ventral identities. By analogy to (...) Drosophila imaginal disc development, this interface has been proposed to determine and position an ectodermal organising centre, the Apical Ectodermal Ridge (AER), controlling limb bud outgrowth. Recent fate mapping studies(1) and studies of genes regulating DV limb polarity(2‐6), AER formation(7,8) and differentiation(9) suggest, however, that DV patterning and AER induction, though coordinately regulated during limb bud outgrowth, may early on be more dissociated than expected. (shrink)

The aim of this paper is to contribute to the clarification of concepts usually found in books on quantum mechanics, aided by knowledge from the field of the theory of operators in Hilbert space. Frequently the basic distinction between bounded and unbounded operators is not established in books on quantum mechanics. It is repeatedly overlooked that the condition for an unbounded operator to be symmetric (Hermitian) is not sufficient to make it self-adjoint. To make things worse, nearly all operators in (...) quantum mechanics are unbounded. Often one finds statements such as: For any linear operator A we can write a Hermitian operator HA=(A+A+)/2, where Hermitian is thought to mean self-adjoint. Along these lines, self-adjointness of the momentum operator in generalized coordinates, taken from that expression, is questioned. In particular, the redescription in terms of spherical polar coordinates and its implications for the eventual loss of self-adjointness of the momenta conjugate to them are studied. (shrink)

The polar orientation of cells within a tissue is an intensively studied research area in animal cells. The term planar polarity refers to the common polar arrangement of cells within the plane of an epithelium. In plants, the subcellular analysis of tissue polarity has been limited by the lack of appropriate markers. Recently, research on plant tissue polarity has come of age. Advances are based on studies of Arabidopsis patterning, cell polarity and auxin transport mutants employing the coordinated, (...) polar localization of auxin transporters and the planar polarity of root epidermal hairs as markers. These approaches have revealed auxin transport and response, vesicular trafficking, membrane sterol and cytoskeletal requirements of tissue polarity. This review summarizes recent progress in research on vascular tissue and planar epidermal polarity in the Arabidopsis root and compares it to findings on planar polarity in animals and cell polarity in yeast. BioEssays 26:719–729, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Peter Singer and Christian Ethics: Beyond Polarization by Charles E. CamosyWerner WolbertPeter Singer and Christian Ethics: Beyond Polarization CHARLES E. CAMOSY Cambridge: Cambridge University Press, 2012. 278 pp. $29.99Peter Singer’s “Copernican revolution” against a sanctity of life ethic may be regarded, from a Roman Catholic viewpoint, as an expression of the “culture of death” denounced by John Paul II. One must keep in mind, however, that “we know (...) that historically there have been times where those participating in discussions about ethics disagree deeply about theory, but nevertheless come to important and even broad agreement about applied or practical ethics” (179). The aim of Camosy’s book is to sketch the various areas of agreement and disagreement between Peter Singer and Catholic moral theology as well as the possibilities of working together.There are issues even about the subject of abortion on which Singer and the Church agree: that moral relativism is wrong; that it is seriously wrong to kill a person; that the right to privacy (see Roe vs. Wade) does not apply to acts harming others; and that the right to abortion is not a constitutional matter (chapter 1). Both positions see a connection between abortion and infanticide, but both draw different conclusions. The disagreements between them are about who is to count as a person, which Camosy comments on in the rest of chapter 1 (27–37). In the area of euthanasia, the Church and Singer share some skepticism about brain death (chapter 2). Camosy discusses the church’s position on one’s moral status at the end of life and the Roman Catholic understandings of ordinary and extraordinary means, acts, and omissions. Commenting on public policy in that field, Camosy gives some useful and convincing illustrations of the slippery slope effect in different countries that have legalized active euthanasia or assisted suicide (68–81).With regard to problems of killing, however, Helga Kuhse’s The Sanctity of Life Doctrine in Medicine (Oxford University Press, 1987) should perhaps have been considered. On the subject of acting and refraining, I would recommend Dieter Birnbacher’s Tun und unterlassen (Reclam 1995).Commenting on Singer’s championing of the moral status of nonhuman animals, Camosy points to elements in the Christian tradition that may support Singer’s issue of animal liberation (chapter 3). I wonder why the discussion concentrates on domestic animals and the problems of eating meat or [End Page 225] vegetarianism but omits problems of environmental ethics (e.g., ecological balance). Would the aim of avoiding animal harm include saving animals from predators? And if some animals are to be regarded as persons, we may get in trouble with our basic conviction of the equality (of the dignity) of human beings—as the debate on the margins of human life shows.Duties to the poor are not in dispute except for “partial preferences” (166) for members of our family, kinship, or country (chapter 4). Speaking of “partiality” in this context is, however, a bit misleading. Since no one can care for all people, preferences of an ordo caritatis (order of love) are a necessary part of a system of coordination from which—ideally—all humans can benefit. (Recall Augustine in De doctrina Christiana, 1.28–29: “The interests of society, however, and its common bonds will be best conserved if kindness be shown to each individual in proportion to the closeness of his relationship.”) Chapter 5, which compares Singer’s ethical theory with Catholic moral theology, would need more discussion (e.g., on double effect, object, and act), which I cannot cover within the limits of this review. Overall, Camosy’s book makes a valuable contribution to the dialogue between Christian and secular ethics.Werner WolbertUniversity of SalzburgCopyright © 2014 Society of Christian Ethics... (shrink)

During gestation, fetomaternal exchange occurs in the villous tree (labyrinth) of the placenta. Development of this structure depends on tightly coordinated cellular processes of branching morphogenesis and differentiation of specialized trophoblast cells. The basal chorionic trophoblast (BCT) cell layer that localizes next to the chorioallantoic interface is of critical importance for labyrinth morphogenesis in rodents. Gcm1‐positive cell clusters within this layer initiate branching morphogenesis thereby guiding allantoic fetal blood vessels towards maternal blood sinuses. Later these cells differentiate and contribute to (...) the syncytiotrophoblast of the fetomaternal barrier. Additional cells within the BCT layer sustain continued morphogenesis, possibly through a repopulating progenitor population. Several mouse mutants highlight the importance of a structurally intact BCT epithelium, and a growing number of studies addresses its patterning and epithelial architecture. Here, we review and discuss emerging concepts in labyrinth development focussing on the biology of the BCT cell layer. (shrink)

This methodological article provides a Mixed Method approach to analyze how the Teaching Personal and Social Responsibility (TPSR) Model is feasible to enhance student’s autonomy. The objective is to detect how teachers’ behavior-oriented patterns shift in response to continuing professional development to reinforce TPSR strategies. We compared the application of TPSR by three teachers who had previously attended a training course for this model, with that of an expert in the model. A total of 44 sessions of primary and secondary (...) school semesters in various subjects, taught by all four teachers and comprising 120 students. A mixed-method approach followed in the study involved: a) the Observational System of Teaching Oriented Responsibility (OSTOR), which revealed how the teachers’ behavior patterns shifted over their interventions, and b) the Tool for Assessing Responsibility-Based Education (TARE 2.0.), which focused on perceived behaviors by teachers and student behaviors. Data analysis was conducted for a) the T-pattern detection technique, b) polar coordinate analysis to obtain detailed sequences of instruction, and c) descriptive and correlational analysis from the TARE. The mixed-method analysis of data confirms how the TPSR improved the teaching behaviors of the three teachers in training compared with the expert teacher. (shrink)

The aim of this article is to know the role of learning tasks within the pedagogical content knowledge of novel sports coaches in initial stages of sports training of children/young people and their impact on their daily work. Participants are two coaches in their first or second working year. A mixed methodology was used by means of polar coordinates analysis. The results agree with previous studies that established that PCK of novel coaches presents deficits in task selection and (...) modification, motivation is the key factor determining tasks selection process, and they do not know how much time they should dedicate to each task. Even so, better development was found in the PCK of the coaches. (shrink)

The dynamic of changes in the rules in team games materialize from research and debate between experts and coaches before being implemented by the International Federations. In Handball, the last changes occurred in 2016, and one of them was to substitute the goalkeeper with an additional field player allowing teams to play “empty goal” while using the additional field player.This study aimed to analyze and characterize the use of the 7 vs. 6 strategical-tactical option for the attack in the 2020 (...) Men’s European Championship. We also analyzed whether the game time and partial score influenced the use of 7 vs. 6 and its efficiency. Observational methodology and a mixed ad hoc instrument combining field format and category systems validated by experts were used. Data were taken from 28 matches involving teams in the first 12 positions in the 2020 Men’s European Championship. The total number of offensive sequences in an organized attack method in 7 vs. 6 with an empty goal were analyzed. Sequential analysis techniques with lags, prospective and retrospective, and polar coordinate analysis were used. The results showed that these solutions had poor efficiency, except for the Portuguese National Team; teams using the 7 vs. 6 tactic option had no negative consequences or increased risk with the opponent response; partial score influenced the decision to use 7 vs. 6 strategic option, and game time was associated with 7 vs. 6 play options and detected patterns. (shrink)

A modern version of Lewis’s theory of valency is presented. This takes account of the results of quantum–mechanical calculations on molecules. Topics covered are polar covalent bonds, hypervalency, coordinate bonds, nonintegral bonds, oxo-anions, variable valency among transition elements, and nonclassical compounds. A distinction is drawn between the valence shell of an atom and the Lewis shell. The concept of a fractional bond pair is presented.

The importance of addressing the existential threat to humanity, climate change, has grown remarkedly in recent years while conflicting views and interests in societies exist. Therefore, climate change agendas have been weaponized to varying degrees, ranging from the international level between countries to the domestic level among political parties. In such contexts, climate change agendas are predominantly driven by political or economic ambitions, sometimes unconnected to concerns for environmental sustainability. Consequently, it can result in an environment that fosters antagonism and (...) disputes over power and position and increases the risk of prolonged confrontations, hindering the collective global efforts to mitigate and adapt to climate change. Through the current discourse, we aim to provide a preliminary definition of the weaponization of climate change and environmental degradation and examine its risks and consequences on international relations, political dynamics, public perception, and the comprehensive integrity of climate action. We also recommend embracing a globally coordinated, scientifically substantiated approach to circumvent climate change by building an eco-surplus cultural value system. (shrink)

We investigate adverbial agreement in Sandəmarkesə (S. Marco in Lamis, Apulia) proposing phase-bound, local agreement relations, reducible to coordination, as in past and absolute participial constructions, suggesting a copulaless analysis where arguments are subjects in a small clause. With disjunct nominals with matching φ-features, the adverb agrees separately with each part in the set, otherwise resulting in ‘non-agreeing’ forms, which we test also with negative polarity items (niʃun-, ‘nobody’ and nentə, ‘nothing’). With fragment answers, the negation scopes over adverbs agreeing (...) with the two proposed topics: matching of the φ-features of both nouns values the negative operator with the same features. In fronted adverbs, agreement occurs when the question contains overt coordinated arguments, elements continuing a chain, and if coordinated arguments have matching φ-features. In agreement in topical contexts with fronted adverbs, agreement occurs with the aboutness-shift topic closely preceding them, rather than with the embedded direct object. (shrink)

In 1992 M.W. Evans proposed the O(3) symmetry of electromagnetic fields by adding a constant longitudinal magnetic field to the well-known transverse electric and magnetic fields of circularly polarized plane waves, such that certain cyclic relations of a so-called O(3) symmetry are fulfilled. Since then M.W. Evans has elevated this O(3) symmetry to the status of a new law of electromagnetics. As a law of physics must be invariant under admissible coordinate transforms, namely Lorentz transforms, in 2000 he published a (...) proof of the Lorentz invariance of O(3) symmetry of electromagnetic fields. As will be shown below this proof is incorrect; more, after simple correction it will turn out here that the O(3) symmetry cannot be Lorentz invariant. (shrink)

Epistemology of science is currently polarized. Descriptive accounts of the social aspects of science coexist uneasily with normative accounts of scientific knowledge. This tension leads students of science to privilege one of these important aspects over the other. I use an episode of recent immunology research to develop an integrative account of scientific inquiry that resolves the tension between sociality and epistemic success. The search for the hematopoietic stem cell by members of Irving Weissman’s laboratory at Stanford University Medical Center (...) exhibits both the goal-oriented character of contemporary immunology and the importance of social interactions in successful achievement of those goals. This episode includes three kinds of epistemic success: characterization of HSC, formation of new interdisciplinary interfaces, and reconciliation of apparently incompatible models. All three depend on coordinating the work of diverse participants via social interactions. Together, they reveal the crucial role of social interactions within and between research groups in producing epistemic success. These features of the search for the HSC generalize to immunology as a whole, and plausibly to other disciplines. This account thus resolves the polarizing tension in epistemology of science, and complements individualistic accounts of scientific knowledge and rationality. (shrink)

Epistemology of science is currently polarized. Descriptive accounts of the social aspects of science coexist uneasily with normative accounts of scientific knowledge. This tension leads students of science to privilege one of these important aspects over the other. I use an episode of recent immunology research to develop an integrative account of scientific inquiry that resolves the tension between sociality and epistemic success. The search for the hematopoietic stem cell (HSC) by members of Irving Weissman’s laboratory at Stanford University Medical (...) Center exhibits both the goal-oriented character of contemporary immunology and the importance of social interactions in successful achievement of those goals. This episode includes three kinds of epistemic success: characterization of HSC, formation of new interdisciplinary interfaces, and reconciliation of apparently incompatible models. All three depend on coordinating the work of diverse participants via social interactions. Together, they reveal the crucial role of social interactions within and between research groups in producing epistemic success. These features of the search for the HSC generalize to immunology as a whole, and plausibly to other disciplines. This account thus resolves the polarizing tension in epistemology of science, and complements individualistic accounts of scientific knowledge and rationality. (shrink)

Located in Kleinbasel close to the Rhine, the Kaskadenkondensator is a place of mediation and experimental, research-and process-based art production with a focus on performance and performative expression. The gallery, founded in 1994, and located on the third floor of the former Sudhaus Warteck Brewery (hence cascade condenser), seeks to develop interactions between artists, theorists and audiences. Eight, maybe, nine or ten 40 litre bags of potting compost lie strewn about the floor of a high-ceilinged white washed hall. Dumped, split (...) open, the soil mixed with iridescent specks of green, blue and red glitter. On the walls hang large black and white photographic images—negative and positive prints barely clean, hardly sharp, scavenged from the world and presented half processed. On a third wall, hangs a framed golden and charcoal surface. Finally, a huge stain of black dye runs down a wall that descends into a sunken quarter of the Kaskadenkondensator gallery space. The results of a collaboration between Oliver Minder and Walter Derungs reflect on themes addressed in the recent Aesthetics in the 21st Century conference held by the department of English, University of Basel. In particular, the joint show questions how an aesthetic experience may be other than a human-world interaction, hinting at the withdrawal and veiling that objects perform, while demanding that different works engage with each other and play out this game under the non-supervisory eyes of a human audience. Things here are becoming—sometimes it’s a movement towards a more complete ontic whole in a projection of finality, other times it’s a dispersal, an atrophy to rather disarrayed entities. Yet, in the moment and place in which the objects are, we take them as here and now. Let’s get to the material of the stuff that Minder and Derungs have assembled. Oliver Minder employs organic materials—potting earth, cuttlefish ink secretion, rice, and insects; yet his works hardly seem natural in the sense of a harmonic relation between material and the form they are constrained into, the objects they are compelled to occupy. For the substrates on, through, or within which these natural materials are mediated are harshly inorganic substances—Plexiglas, safety glass, acrylic resin, boat varnish, spray paint. Minder, thus, generates a conflict within the materiality of his work between two polar opposites—from the human perspective—in the contiguity of materials engaging with each other in a thrown together formation that nonetheless appears to keep the materials and the objects they make in happy accidental relation to each other. Let me expand a little: on the one hand, the things Minder makes query our belief in substance as belonging in a particular domain, an environment suited to precisely that stuff. We are focused on thinking categorically where things belong, both in terms of natural place and natural relations they might extend to each other. Hence, we are driven to think of environment and order. On the other hand, while extracting things from their conventional place and arranging them within awkward constellations that we as observers feel isn’t quite right, Minder manages to persuade the viewer that the materials are nonetheless “doing alright.” So, simultaneous to our awareness of the appropriateness of the world according to our global notions of accord and uniformity, we are forced to accept the local discrepancies of disassociation, inappropriateness and misplacement. The tension between these two vectors generates a vacillation that intensifies Minder’s work. In the Kaskadenkondensator works, then, it is vital to first consider the material of Minder’s works: potting compost—what is it doing here in the first place?—seems to enjoy being “polluted” by sparkly glitter. Glitter has a long history, used in cosmetics by the Egyptians, and in cave paintings, too, earlier made of beetle shells and mica, nowadays glitter is made of plastic cut to minute sizes down to 50 microns. So what’s the point here? Well shiny bits of dust-like material are actually generated from ultra-thin plastic sheets and are normally cut into shapes that fit contiguously on a two-dimensional surface: squares, triangles, hexagons etc. What then appears to be totally random, chaotic decoration, is actually an array of extremely regular identifiable objects. 1 Of course scale has a role to play here. The minuteness of the dimensions means the regularity is beyond our recognition—all we see are the twinkling surfaces of the multi-coloured grains of plastic. In contrast, potting compost, which appears to be unary in its dull unresponsive lumpen disposition, is in fact an amalgam of a variety of organic and inorganic materials: peat, bark, mushroom compost, and sand and perlite, and should perhaps be more proactively exciting to the viewer because of this complexity. Yes; we can (if we care to) identify different textures, different sizes in the mixture of the medium, but I claim that we tend to treat this organic/inorganic assemblage as just a simple substance. Further and crucially important to our consideration here is that the medium is partially contained, but also partially spilling from the split plastic bags in which it is sold in garden centres. That the compost spills out gives it a movement suggesting life; that the bags are cast here and there in a random fashion by Oliver Minder, lying like discarded carcasses, hacked torsos, dismembered bodies, suggests a horrific murder scene, a Tatort. 2 The glitter flourishes in the medium, lies happy and decorative; that is simply what it does, how it is—always already broken, made-for-scattering, designed to be incomplete; the taken-to-be-natural compost, in contrast, cannot rest content but is forced to speak to us metaphorically in its abject overflowing of violence and rupture. While Oliver Minder’s elements in the installation direct our attention to material, Walter Derungs’ works raise questions around seeing and making in photography. There is a simultaneous flicker between the materials and their use in the production of a sense making representation, on the one hand, and on the other the very notion of what is worthy of picturing, framing, representing on the other. Derungs' images are of non-places. Ranging from archaic decaying monster buildings, buildings that have gone far beyond the ravages of a time that we can safely associate with the genteel preservation of a Bernd and Hill Belcher post-industrial decline, to the background “noise” of an urban world that is falling apart, and to which we most of the time seem to pay little attention, and habitually just pass by. In this respect, their non-ness differs somewhat from the conventional association of the term with Marc Augé 3 , where emphasis is on the specifics (if we do care to examine them for their non-placedness) of the spatial or place containment in which movement between multimodal coordinates occurs in supermodern late capitalist post-urban spaces. In other words, we might be in an Augéian non-place and (not) experience—be impervious to—that environment, or we might in Derungs’ manner look out from such a position at the “scenery” around us. I claim scenery, as this is what Derungs seems to do with his partial photography—construct a very purposefully articulated, symmetric, flat world of image. Mostly depopulated, his images construct a space in which the direction of time is uncertain: are these partial structures falling apart, or perhaps terminated in a never-to-be-completed state, or are they a few steps from final completion? Temporal and spatial dimensions figure large in Derungs’ image-making: his world, and perhaps this is in fact the only way for it to be registered photographically, is already image before it is photographed. A key combination of images in this show is a matrix of six black and white negative prints measuring 300 x 215 cm that form the image of a semi-derelict (or is it yet incomplete) church, and adjacent on a perpendicular wall, a single black and white positive print 150 x 250 cm of two bricked-up windows of a late-Victorian industrial building. What are we led to believe that we see here? In the negative print, the conditions of perception 4 are sufficiently reproduced for us to recognise the structure of the building, to distinguish ground and form, to relate some partial elements of narrative, and to recognize symbols such as the alter cross and figure of Christ, a looming crane, a traffic cone, and banks of tiered seating. We piece the image together both from the individual forms which we recognize despite the tonal reversal, and we piece the six prints together as a whole, the matrix of lines between them emphasizing our purview onto the world. While we recognise the forms at work in the image and might possibly relate the negative reversals to other figurations such as Vera Lutter’s camera obscura exposures, we cannot but avoid seeing the partialness of the image in the sponge marks of the developer that was spread by hand across the prints. 5 Derungs’ thus intervenes with our usual conception of photography as the mimetic realist vehicle sine qua non , by exposing the viewer to tonal reversal and incomplete or over developed areas of the print. We thus confront both the idiom of such image making and its raw (chemical) materiality at once in the simultaneity of the recognition of what the image pictures and the recognition that it is in the act of picturing. The church image, taken from the series “BW Negativs 2011,” thus orients us towards how we see things in the world via photographs. The single image of the bricked-up wall presents us with a completely different visuality that relates to a faciality 6 which we cannot easily escape from. We look, or rather try to look with no success, through the face of the windows, through the classic Albertian screen 7 which has already been given to us in the church matrix beside. Yet although we should be able to make more of these concealed windows because they are a positive print, because they are complete, because they approach us on a more realistic scale, reproduced at life size, we cannot. The objects pictured here withdraw from us; furthermore, they merely mock our blindness at not seeing how we look. Blocked up with quite a hint of paned glass behind, one window is blanked out with a white blind, the other simply blankly dark. The apertures look like eyes with teeth in them, or a Dogon mask, or even Man Ray’s Noire et Blanche (1926) if we want to get really perverse. The height of elegant modernist chauvinist beauty thrown against the vacuity of post-industrial decline. Derungs thus catapults us consciously into a world enfolded with and through images, but in such a way that the images themselves become objects that stand resistant to us, impervious to our gaze, indifferent. We—and indeed they—do not attempt to reach out to a real that is beyond, rather the images play in a world that is just theirs, and we can only enter that world if we too submit to their regime: tonal reversal, segmented, partial, inadequate, still, wrenched out of time. In contemplation, in the flood of the image “falling” off the wall, we too become image-object. Perhaps enough has now been said about the works, yet enough can never really be said, we know the image will always exceed the word—let’s accelerate the critique: Derungs’ work continues in a second space partially partitioned from this first room. Opposing three more “BW Negativs” which figure yet more quotidian aspects of the world is Minder’s gold spray paint and cuttlefish secretion mix: things that just shouldn’t work together do in the dialogue between stuff that Derungs and Minder have constructed. Minder makes things; Derungs makes images; together they make objects which inhabit their own world which we can approach and sensually engage with and come to grips with only on those objects’ own terms. This is best summarised by a final work made by Oliver Minder which on a third wall faces these two semi-partitioned spaces. A deep black stain about 100 X 200 cm with streak marks running down a further 2 metres hovers positioned to observe the whole work, and also to be part of this installation, too. This liminal flat suzerain lies in/out of the whole work. The stain of cuttlefish secretion resonates with Derungs’ sponge strokes on the church image; it mirrors the iris of an all-seeing eye; it combines material in situ with the situation itself. Where Minder’s other works have material and medium or substrate upon which the material is exercised, this single black hole is image which sucks everything up into itself. It draws the viewer, who must otherwise look away attentively at the floor work, and imagine horror, or smile at the ironic play of glitter. Look away at the image constructions that suggest how it is we too look to our world. See the play of thing and image in a third area. Or, finally return to the base of the pyramid that triangulates, to realise the stuff-image that unlocks it all for us. Black on white, organic on inorganic, material to substrate, that which in the falling out of one on the other, in its running down the wall simply gives form to both content and expression in one direction, and content and expression to form in another. NOTES In fact, glitter is used as associative forensic evidence: the 20,000 or so varieties are all uniquely identifiable. Joel Sternfeld, Tatorte: Bilder gegen das Vergessen (München: Schirmer/Mosel, 1996). Marc Augé, Non­places: Introduction to an Anthropology of Supermodernity trans. John Howe (London: Verso, 2006). An echo of the uneven paint strokes of light­sensitive chemicals in the paper preparations made by Henry Talbot some 170 years ago in the first sun drawings that also often pictured architectural forms. It was Talbot’s surprising discovery that where a weaker chemical solution was more thinly spread, greater light sensitivity was actualized, yet this virtual image had then to be chemically developed in a second step. Thus, Derungs unevenly finished spongings suggestively trace back to this originary technology (although his sweeps are the stains of uneven development and not those of the initial preparation of light–sensitive material). Umberto Eco, “Critique of the Image” in “Articulations of Cinematic Code” Cinematics 1, 1970. Gilles Deleuze and Felix Guattari, A Thousand Plateaus: Capitalism and Schizophrenia trans. Brian Massumi (Minneapolis: University of Minnesota Press, 2007). Geoffrey Batchen, Burning With Desire: the Conception of Photography (Cambridge, Mass: MIT Press, 1999). (shrink)

Rho/Rac proteins constitute a subgroup of the Ras superfamily of GTP hydrolases. Although originally implicated in the control of cytoskeletal events, it is currently known that these GTPases coordinate diverse cellular functions, including cell polarity, vesicular trafficking, the cell cycle and transcriptomal dynamics. In this review, we will provide an overview on the recent advances in this field regarding the mechanism of regulation and signaling, and the roles in vivo of this important GTPase family. BioEssays 29:356–370, 2007. © 2007 Wiley (...) Periodicals, Inc. (shrink)

The establishment of a functional vascular system requires multiple complex steps throughout embryogenesis, from endothelial cell (EC) specification to vascular patterning into venous and arterial hierarchies. Following the initial assembly of ECs into a network of cord‐like structures, vascular expansion and remodeling occur rapidly through morphogenetic events including vessel sprouting, fusion, and pruning. In addition, vascular morphogenesis encompasses the process of lumen formation, critical for the transformation of cords into perfusable vascular tubes. Studies in mouse, zebrafish, frog, and human endothelial (...) cells have begun to outline the cellular and molecular requirements underlying lumen formation. Although the lumen can be generated through diverse mechanisms, the coordinated participation of multiple conserved molecules including transcription factors, small GTPases, and adhesion and polarity proteins remains a fundamental principle, leading us closer to a more thorough understanding of this complex event. (shrink)

The specification of specific and often unique fates to individual cells as a function of their position within a developing organism is a fundamental process during the development of multicellular organisms. The development of the Drosophila embryonic central nervous system serves as an excellent model system in which to clarify the developmental mechanisms that link pattern formation to cell-type specification. The Drosophila embryonic central nervous system develops from a set of neural stem cells termed neuroblasts. Neuroblasts arise from the ectoderm (...) in an invariant pattern, and each neuroblast acquires a unique fate based on its position within this pattern. Two groups of genes recently have been demonstrated to govern the individual fate specification of neuroblasts. One group, the segment polarity genes, enables neuroblasts that develop in different anteroposterior positions to acquire different fates. The second group, referred to as the columnar genes, ensures that neuroblasts that develop in different dorsoventral domains assume different fates. When integrated, the activities of the segment polarity and columnar genes create a Cartesian coordinate system that bestows unique fates to individual neuroblasts as a function of their position of formation within the ectoderm. BioEssays 1999;21:922–931. © 1999 John Wiley & Sons, Inc. (shrink)

Mathematics from the electromagnetic field quantization procedure and the soliton models of photons are used to construct a new 3D model of photons. Besides the interaction potential between the charged particle and the photons, which contains the annihilation and creation operators of photons, the new function for a description of free propagating photons is derived. This function presents the vector potential of the field, the function is a product of the harmonic oscillator eigenfunction with the well-defined coordinate of the oscillator (...) and the Gaussian function of the polar radius in the transverse direction. In the article, the difference between the quantum mechanics of particles and photons is discussed. (shrink)

Irregularity may occur on the earth’s surface in the form of mountains due to the imperfection of the earth’s crust. To explore the influence of horizontally polarized shear waves on mountains, we considered the fluid-saturated porous medium over an orthotropic semi-infinite medium with rigid and soft mountain surfaces for wave propagation. The mountain surface is defined mathematically as a periodic function of the time domain. The physical interpretation of materials’ structure has been explained in rectangular Cartesian coordinate system originated at (...) the contact interface of layer and half-space. The displacement of the mountains has been derived by solving energy equations analytically. The influence of rigid and soft mountain surfaces on the phase velocity of shear waves has been demonstrated graphically. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Rationalist Empiricism: A Theory of Speculative Critique by Nathan BrownGreg EllermannBrown, Nathan. Rationalist Empiricism: A Theory of Speculative Critique. Fordham University Press, 2021. 318pp.Nathan Brown's Rationalist Empiricism is, above all, a book about philosophical method. It is also a highly significant study of the conceptual architecture of Marxism, developed by way of a critical return to the lesson of Althusser. Drawing on a range of disparate materials–from the (...) works of Descartes, Hume, Hegel, Marx, Heidegger, and Meillassoux to contemporary experiments in digital photography and metrology–Brown demonstrates the necessity of "a mutual interruption of reason and experience" (31) for any theoretical or political practice that would avoid falling into ideological complacency.The book opens with an appraisal of "the speculative turn" (1) in 21st-century thought, a turn Brown characterizes as an intellectual dead-end. He remarks that the various new materialisms and object-oriented ontologies of the last decades were united by an inattention to method. Unconcerned to establish the necessity of their claims or with the relation between reasoning and reality, these philosophies made assertions instead of arguments; they mistook dogmatism for speculation.For Brown, it is the dialectic–specifically, the dialectic of reason and experience–that promises to renew the possibility of speculative thinking. Such renewal will entail refusing "the severance of speculation from critique" (2). It also requires thinking through a more basic problem: the relation between rationalism and empiricism. While rationalism "explore[s] what has to be thought according to the internal order and consistency of ideas," empiricism, as Brown has it, "claim[s] the genesis of ideas in experience" (3). Since Kant's first Critique, this binary and the effort to overcome it have set the terms of philosophical debate. Brown's striking contention is that the search for a synthesis or a hidden ground uniting these two positions (as, for instance, in Deleuze or Michel Henry) invariably leads us back to the transcendental–an improvement on the dogmatism of contemporary theory but a reduction of knowledge to "conditions of experience" [End Page 128] nonetheless (47). Brown therefore proposes another path: "a relational disjunction of rationalism and empiricism" animated by "the critical power of the tension between [them] to check one another's claims and to propel those claims further" (3). In other words, he develops a methodological dialectic whose two poles-the rationalist and the empiricist-alternately take on speculative and critical functions. There is no static alignment of the key categories in Brown's book. "Speculation and critique cannot be parceled out," he writes, "according to the division of reason and experience. Metaphysics, science, politics: each of these fields relies integrally upon the conflict and complementarity of reason and experience, their 'epistemological polarity'" (250). In Bachelard's terms, pivotal for the overall argument, reason and experience must be allowed to "transmute," "propel," and "say 'no' to one another" (8). It is their ungrounded dialectical relation that sustains true speculative thought.This methodological position has profound ontological implications. Looking to Althusser, Brown finds the beginnings of a theory of rationalist empiricism in the structural Marxist notion of the "concrete-in-thought" (15-16): the self-critical and experimentally verified knowledge of a science. Crucially, for Althusser there can be no concrete-in-thought without a "concrete-real," external to theory itself (15). Developing to the fullest this underappreciated point, Brown shows that rationalist empiricism must be a realism. Thus, the book's second, third, and fourth chapters elaborate a continuous argument concerning "the primacy of being over thought" (59), and the relationship between speculative and scientific knowledge. The central question is how speculation might extend or "extrapolate from the exteriorizing force of science, without being reducible to its forms of experience" (261). Refracting Hegel's Logic through the thought of Heidegger and Meillassoux, Brown ultimately offers a new account of the ontological difference–between being and beings, between speculative truth and "ontic," scientific knowledge–that privileges neither side and insists on their coordination. Once again, he declines to seek a synthesis, arguing that "true critique" (as Hegel characterized his speculative method) depends on "the ontological primacy of becoming" (91), on an absolute time bound up with... (shrink)

The specification of specific and often unique fates to individual cells as a function of their position within a developing organism is a fundamental process during the development of multicellular organisms. The development of the Drosophila embryonic central nervous system serves as an excellent model system in which to clarify the developmental mechanisms that link pattern formation to cell-type specification. The Drosophila embryonic central nervous system develops from a set of neural stem cells termed neuroblasts. Neuroblasts arise from the ectoderm (...) in an invariant pattern, and each neuroblast acquires a unique fate based on its position within this pattern. Two groups of genes recently have been demonstrated to govern the individual fate specification of neuroblasts. One group, the segment polarity genes, enables neuroblasts that develop in different anteroposterior positions to acquire different fates. The second group, referred to as the columnar genes, ensures that neuroblasts that develop in different dorsoventral domains assume different fates. When integrated, the activities of the segment polarity and columnar genes create a Cartesian coordinate system that bestows unique fates to individual neuroblasts as a function of their position of formation within the ectoderm. BioEssays 1999;21:922–931. © 1999 John Wiley & Sons, Inc. (shrink)

The artistic work of photographer Gudio Baselgia focuses on landscapes formed by nature s forces and, more recently, on the sky with the stellar and solar movements and phenomena as we see them from earth. Celestial mechanics have fascinated mankind in all known cultures, the Babylonians and ancient Egyptians as well as the Greek and Celts, the Maya, or the ancient Indians and Chinese. Until the present day we look at the sky and keep being amazed, and try to read (...) what it tells us. Many artists throughout history have been captivated by the spectacle we observe above us day and night. The modern term astrodynamics describes all movements of celestial bodies, in particular the solar system including the moon and other satellites, asteroids and comets, but also movements of stars within a stellar system or galaxy, or of galaxies towards each other. They are well understood today and depicted in coordinate systems and elaborate visualizations. Guido Baselgia s artistic project on astrodynamics and celestial phenomena has no scientific or didactic ambition. His analogue camera is used as a recorder inscribing the movement of stars on the light-sensitive surface of photographic paper. Thus Baselgia s images make traceable the trajectory of celestial bodies invisible to the human eye and show us astounding occurrences of light and shadow. Baselgia has been captivated in particular also by the phenomenon of the umbra, planet earth s shadow thrown into space. It becomes visible occasionally on a clear evening at sunset when a slight mist lies at the horizon: looking in opposite direction to the sun, a dark and sharply marked band of shadow can be seen rising while sun sets behind the observer. But also by recording sunrise and sunset at the polar circle or the tropic, Baselgia visualizes the geometry of celestial mechanics and the concurrence of forces, as well as the miracle of light as such that leaves us awestruck today as much as it did our ancestors. The new book "Guido Baselgia Light Fall" presents 80 outstanding black-and-white images from the artist s Light Fall project taken in Norway, the Tierra del Fuego archipelago in Argentina, in Ecuador, and the Swiss Alps. The brilliant tritone plates are complemented with essays by the German scholar Andrea Gnam and Swiss photography critic Nadine Olonetzky. ". (shrink)