Although chemical phenomena are primarily associated with electrons in atoms, ions, and molecules, the masses, charges, spins, and other properties of the nuclei in these species contribute significantly as well. Isotopes, for instance, have proven invaluable in chemistry, in particular the elucidation of reaction mechanisms. Elements with unstable nuclei, for example carbon-14 undergoing beta decay, have enriched chemistry and many other scientific disciplines. The nuclei of all elements have a much more subtle and largely unknown effect on (...) chemical phenomena. All nuclei are innately chiral and, because electrons can penetrate nuclei, all atoms and molecules are likewise chiral. This article describes in considerable detail the discovery of chiral nuclei, how this unusual chirality may influence the chemical behavior of atoms and molecules, and how atomic chirality may have been responsible for the synthesis of optically active molecules in the pre-biotic world. (shrink)

Medium- and high-spin states of Pr-134 were populated using the Cd-116(Na-23, 5n) reaction and studied with the GAMMASPHERE spectrometer. Several new bands have been found in this nucleus, one of them being linked to the previously observed chiral-candidate twin-band structure. The ground state of Pr-134 could be determined through establishing a level structure that connects the two previously known long-lived isomeric states. Unambiguous spin-parity assignments for the excited states could be performed based on the known 2(-) spin-parity of the (...) ground state combined with the present experimental data. Intrinsic single-particle configurations have been assigned to the newly observed bands on the basis of the measured B(M1)/B(E2) ratios, alignments, band-crossing frequencies, bandhead spins, the observed single-particle configurations in the neighboring nuclei, and taking into account the predictions of total Routhian surface and tilted-axis cranking calculations. (shrink)

Relativistic mean field theory with mesons σ, ω, π and ρ mediating interactions and nucleons as basic fermions has been very successful in describing nuclear matter and finite nuclei. However, in heavy-ion collisions, where the c. m. energy of two colliding nucleons will be in the hundreds of GeV region, nucleons are not expected to behave as point-like particles. Analyses of elastic pp and ¯pp scattering data in the relevant c. m. energy range show that the nucleon is a (...) composite object—a topological soliton or Skyrmion embedded in a condensed quark-antiquark ground state. Against this backdrop, we formulate an effective field theory model of nuclear matter based on the gauged linear σ-model where quarks are the basic fermions, but the mesons still mediate the interactions. The model describes the nucleon as a Skyrmion and produces a q¯q ground state analogous to a superconducting ground state. Quarks are quasi-particles in this ground state. When the temperature exceeds a critical value, the scalar field in the ground state vanishes, quarks become massless, and a chiral phase transition occurs leading to chiral symmetry restoration. We explore the possibility of a first order phase transition in this model by introducing suitable self-interactions of the scalar field. Internal structures of the Skyrmions are ignored, and they are treated as point-like fermions. (shrink)

I suspect that most readers will, like me, be unfamiliar with the concept of chirality. Indeed I had never heard of the term before reading Dahlen’s paper proposing the completely novel concept of...

Kramers's equation specialized to the Coulomb field is factored using a rotationally invariant, angular momentum based, algebra of three anticommuting operators. Comparing the explicit chiral two-component solutions for the factored equation to the two-component solutions defined by the Foldy-Wouthuysen series for the Dirac-Coulomb Hamiltonian, it is concluded that this series cannot converge.

The measure of the chiral system inertia has been suggested as a reciprocal value of degree of chirality. Three main laws of conservation, evolution, and interaction of chiral systems in the inertial space are formulated. Some of the consequences concerning the interaction of the chiral elements could be used to estimate the degree of chirality of complex chiral systems.

It is a classic result in lattice theory that a poset is a complete lattice iff it can be realized as fixpoints of a closure operator on a powerset. Dragalin [9,10] observed that a poset is a locale (complete Heyting algebra) iff it can be realized as fixpoints of a nucleus on the locale of upsets of a poset. He also showed how to generate a nucleus on upsets by adding a structure of “paths” to a poset, forming what we (...) call a Dragalin frame. This allowed Dragalin to introduce a semantics for intuitionistic logic that generalizes Beth and Kripke semantics. He proved that every spatial locale (locale of open sets of a topological space) can be realized as fixpoints of the nucleus generated by a Dragalin frame. In this paper, we strengthen Dragalin’s result and prove that every locale—not only spatial locales—can be realized as fixpoints of the nucleus generated by a Dragalin frame. In fact, we prove the stronger result that for every nucleus on the upsets of a poset, there is a Dragalin frame based on that poset that generates the given nucleus. We then compare Dragalin’s approach to generating nuclei with the relational approach of Fairtlough and Mendler [11], based on what we call FM-frames. Surprisingly, every Dragalin frame can be turned into an equivalent FM-frame, albeit on a different poset. Thus, every locale can be realized as fixpoints of the nucleus generated by an FM-frame. Finally, we consider the relational approach of Goldblatt [13] and characterize the locales that can be realized using Goldblatt frames. (shrink)

Le chiasme de l’être: une exploration de l’ontologie du sens de Merleau-PontyLa question de l’ontologie inclut celle de savoir comment un être se détermine et acquiert son sens, autrement dit comment il instaure sa différenciation par desorientations, des significations et des différences en général. Cette étude explore l’idée que le sens d’un être provient d’une « chiralité ontologique », c’est-à-dire d’un type de différence ontologique présentant un apparentement caractéristique de ses deux côtés droit et gauche. L’étude montre tout d’abord comment (...) l’ontologie merleau-pontienne de la réversibilité conduit à la question de la chiralité. On fait ensuite entrer dans la discussion des résultats obtenus dans les domaines de la chimie, de la biologie et de la géométrie, pour mieux mettre en lumière l’importance des différences en chiralité et pour élaborer une définition de la « chiralité ontologique » en étroite liaison avec l’ontologie du sens.Il chiasma dell’essere: un’esplorazione dell’ontologia del senso merleau-pontianaIl problema dell’ontologia include il problema di come l’essere sia determinato e acquisisca senso, acquisisca cioè gli orientamenti, i significati, tutte quelle differenze che fanno la differenza. Questo saggio esplora il pensiero secondo il quale il senso dell’essere deriva da una ‘chiralità ontologica,’ una sorta di differenza ontologica con caratteristiche affini alle differenze fra le mani destra e sinistra. Il testo illustra in primo luogo come l’ontologia merleau-pontyana della reversibilità porti alle questioni della chiralità. I risultati della ricerca attuale, in chimica, biologia e geometria sono poi discussi per illuminare l’importanza delle differenze chirali e per sviluppare una definizione della chiralità ontologica che si connette ad una ontologia del senso. (shrink)

Le chiasme de l’être: une exploration de l’ontologie du sens de Merleau-PontyLa question de l’ontologie inclut celle de savoir comment un être se détermine et acquiert son sens, autrement dit comment il instaure sa différenciation par desorientations, des significations et des différences en général. Cette étude explore l’idée que le sens d’un être provient d’une « chiralité ontologique », c’est-à-dire d’un type de différence ontologique présentant un apparentement caractéristique de ses deux côtés droit et gauche. L’étude montre tout d’abord comment (...) l’ontologie merleau-pontienne de la réversibilité conduit à la question de la chiralité. On fait ensuite entrer dans la discussion des résultats obtenus dans les domaines de la chimie, de la biologie et de la géométrie, pour mieux mettre en lumière l’importance des différences en chiralité et pour élaborer une définition de la « chiralité ontologique » en étroite liaison avec l’ontologie du sens.Il chiasma dell’essere: un’esplorazione dell’ontologia del senso merleau-pontianaIl problema dell’ontologia include il problema di come l’essere sia determinato e acquisisca senso, acquisisca cioè gli orientamenti, i significati, tutte quelle differenze che fanno la differenza. Questo saggio esplora il pensiero secondo il quale il senso dell’essere deriva da una ‘chiralità ontologica,’ una sorta di differenza ontologica con caratteristiche affini alle differenze fra le mani destra e sinistra. Il testo illustra in primo luogo come l’ontologia merleau-pontyana della reversibilità porti alle questioni della chiralità. I risultati della ricerca attuale, in chimica, biologia e geometria sono poi discussi per illuminare l’importanza delle differenze chirali e per sviluppare una definizione della chiralità ontologica che si connette ad una ontologia del senso. (shrink)

Le chiasme de l’être: une exploration de l’ontologie du sens de Merleau-PontyLa question de l’ontologie inclut celle de savoir comment un être se détermine et acquiert son sens, autrement dit comment il instaure sa différenciation par desorientations, des significations et des différences en général. Cette étude explore l’idée que le sens d’un être provient d’une « chiralité ontologique », c’est-à-dire d’un type de différence ontologique présentant un apparentement caractéristique de ses deux côtés droit et gauche. L’étude montre tout d’abord comment (...) l’ontologie merleau-pontienne de la réversibilité conduit à la question de la chiralité. On fait ensuite entrer dans la discussion des résultats obtenus dans les domaines de la chimie, de la biologie et de la géométrie, pour mieux mettre en lumière l’importance des différences en chiralité et pour élaborer une définition de la « chiralité ontologique » en étroite liaison avec l’ontologie du sens.Il chiasma dell’essere: un’esplorazione dell’ontologia del senso merleau-pontianaIl problema dell’ontologia include il problema di come l’essere sia determinato e acquisisca senso, acquisisca cioè gli orientamenti, i significati, tutte quelle differenze che fanno la differenza. Questo saggio esplora il pensiero secondo il quale il senso dell’essere deriva da una ‘chiralità ontologica,’ una sorta di differenza ontologica con caratteristiche affini alle differenze fra le mani destra e sinistra. Il testo illustra in primo luogo come l’ontologia merleau-pontyana della reversibilità porti alle questioni della chiralità. I risultati della ricerca attuale, in chimica, biologia e geometria sono poi discussi per illuminare l’importanza delle differenze chirali e per sviluppare una definizione della chiralità ontologica che si connette ad una ontologia del senso. (shrink)

In biological electron transport the spin, and thus the magnetic property of electrons, is neglected. Furthermore, no attention is paid to the fact that the great majority of biologically important molecules are chiral, and during excitation a magnetic moment is induced in them. It is shown, both theoretically and experimentally, that the magnetic moment of the electron and the magnetic transition moment of the optically active molecules may interact. The main consequences of such an interaction are a higher probability (...) of the occurrence of optically active molecules in triplet states, and the polarization of transported electrons. (shrink)

The regularization of chiral gauge theories is reviewed from the “overlap” point of riew. This is a brief and biased review containing no references.

Abstract. The aim of this paper is to show that the topological interpretation of knowledge as an interior kernel operator K of a topological space (X, OX) comes along with a partially ordered family of belief modalities B that fit K in the sense that the pairs (K, B) satisfy all axioms of Stalnaker’s KB logic of knowledge and belief with the exception of the contentious axiom of negative introspection (NI). The new belief modalities B introduced in this paper are (...) defined with the help of the (dense) nuclei of the Heyting algebra OX of open subsets on the topological space (X, OX). In this way, the natural context for the belief operators B related to topological knowledge operator K is shown to be the Heyting algebra NUC(OX) of the nuclei of the Heyting algebra OX.1 More precisely, the dense nuclei of NUC(OX) can be used to define a variety of bimodal logics of knowledge operators K and belief operators B. The operators K and B are compatible with each other in the sense that the pairs (K, B) satisfy all axioms of Stalnaker’s KB system with the exception of the axiom (NI). Therefore, for (X, OX), one obtains a bounded, partially ordered family of belief operators B defined by the elements of NUC(OX). (shrink)

In a rather old paper, Mario Liu described a hydrodynamic Maxwell equations. While he also discussed potential implications of these new approaches to superconductors, such a discussion of electrodynamics of superconductors is made only after Tajmar’s paper. Therefore, in this paper we present for the first time a derivation of fluidic Maxwell-Proca equations. The name of fluidic Maxwell-Proca is proposed because the equations were based on modifying Maxwell-Proca and Hirsch’s theory of electrodynamics of superconductor. It is hoped that this paper (...) may stimulate further investigations and experiments in superconductor. It may be expected to have some impact to cosmology modeling too, for instance we consider a hypothetical argument that photon mass can be origin of gravitation. Then, after combining with the so-called chiral modification of Maxwell equations (after Spröessig), then we consider chiral Maxwell-Proca equations as possible alternative of gravitation theory. Such a hypothesis has never considered in literature to the best of our knowledge. (shrink)

Thetranslation Chern-Simons type three-formcoframe∧torsion on a Riemann-Cartan spacetime is related (by differentiation) to the Nieh-Yan fourform. Following Chandia and Zanelli, two spaces with nontrivial translational Chern-Simons forms are discussed. We then demonstrate, first within the classical Einstein-Cartan-Dirac theory and second in the quantum heat kernel approach to the Dirac operator, how the Nieh-Yan form surfaces in both contexts, in contrast to what has been assumed previously.

In a new paper in recent issue of this journal (PSTJ), Prof. M. Pitkanen describes a solar system model inspired by spiral galaxies. While we appreciate his new approach, we find it lacks substantial discussion on the nature of vortices and chirality in galaxy. Therefore we submit a viewpoint that Gross-Pitaevskii model can be a more complete description of both solar system and also spiral galaxies, especially taking into account the nature of chirality and vortices in galaxies. In this article, (...) we also hope to bring out some correspondence among existing models, so we discuss shortly: the topological vortice approach, Burgers equation in the light of KAM theory, and the Cantorian Navier-Stokes approach. Of course, this short article is far from being complete. We hope further investigation can be done around this line of approach. Aim of this paper: With this article, we hope to begin a healthy dialogue with Prof. M. Pitkanen, especially on his solar system model, since we also believe that he also support “evidence-based physics.” Limitation: In this paper we only discuss Pitkanen’s solar system model, we don’t discuss his other papers in a recent issue of PSTJ. (shrink)

Research on early-divergent angiosperms, including Amborella, the putative sister to all other extant angiosperms, is increasingly used as a yardstick to infer the nature of the hypothetical ancestral angiosperm. Some traits are relatively diverse (and hence relatively labile) in this phylogenetic grade, compared with the more derived eudicot clade, in which developmental patterns have become increasingly canalized. One of the many mysteries surrounding the origin of the angiosperms is the evolutionary origin of the Polygonum-type embryo sac (monosporic, eight-nucleate and seven-celled) (...) that occurs in the majority of flowering plants. Observations on the megagametophyte of Amborella are conflicting, but a recent report of a supernumerary synergid in this genus1 raises the question of whether the Polygonum-type embryo sac is derived by duplication of a four-nucleate structure or by reduction from a multicellular structure. BioEssays 28: 1067–1071, 2006. © 2006 Wiley Periodicals, Inc. (shrink)

Recent work by Busaniche, Galatos and Marcos introduced a very general twist construction, based on the notion of _conucleus_, which subsumes most existing approaches. In the present paper we extend this framework one step further, so as to allow us to construct and represent algebras which possess a negation that is not necessarily involutive. Our aim is to capture the main properties of the largest class that admits such a representation, as well as to be able to recover the well-known (...) cases—such as _(quasi-)Nelson algebras_ and _(quasi-)N4-lattices_—as particular instances of the general construction. We pursue two approaches, one that directly generalizes the classical Rasiowa construction for Nelson algebras, and an alternative one that allows us to study twist-algebras within the theory of residuated lattices. (shrink)

Objective Manic and depressive phases of bipolar disorder (BD) show opposite psychomotor symptoms. Neuronally, these may depend on altered relationships between sensorimotor network (SMN) and subcortical structures. The study aimed to investigate the functional relationships of SMN with substantia nigra (SN) and raphe nuclei (RN) via subcortical-cortical loops, and their alteration in bipolar mania and depression, as characterized by psychomotor excitation and inhibition. -/- Method In this resting-state functional magnetic resonance imaging (fMRI) study on healthy (n = 67) and (...) BD patients (n = 100), (1) functional connectivity (FC) between thalamus and SMN was calculated and correlated with FC from SN or RN to basal ganglia (BG)/thalamus in healthy; (2) using an a-priori-driven approach, thalamus-SMN FC, SN-BG/thalamus FC, and RN-BG/thalamus FC were compared between healthy and BD, focusing on manic (n = 34) and inhibited depressed (n = 21) patients. -/- Results (1) In healthy, the thalamus-SMN FC showed a quadratic correlation with SN-BG/thalamus FC and a linear negative correlation with RN-BG/thalamus FC. Accordingly, the SN-related FC appears to enable the thalamus-SMN coupling, while the RN-related FC affects it favoring anti-correlation. (2) In BD, mania showed an increase in thalamus-SMN FC toward positive values (ie, thalamus-SMN abnormal coupling) paralleled by reduction of RN-BG/thalamus FC. By contrast, inhibited depression showed a decrease in thalamus-SMN FC toward around-zero values (ie, thalamus-SMN disconnection) paralleled by reduction of SN-BG/thalamus FC (and RN-BG/thalamus FC). The results were replicated in independent HC and BD datasets. -/- Conclusions These findings suggest an abnormal relationship of SMN with neurotransmitters-related areas via subcortical-cortical loops in mania and inhibited depression, finally resulting in psychomotor alterations. (shrink)

Purified nuclei are being used as a test system to study the regulation of nuclear enzymes in plants. Regulatory agents such as light, hormones and polyamines can stimulate kinases or phosphatases that control nuclear protein phosphorylation and they can modulate the activity of as yet unidentified enzymes required for transcript synthesis and/or stabilization. This essay summarizes current findings and discusses the advantages and pitfalls of using isolated nuclei to investigate how nuclear functions are controlled.

This paper outlines a new interpretation of an argument of Kant's for the existence of absolute space. The Kant argument, found in a 1768 essay on topology, argues for the existence of Newtonian-Euclidean absolute space on the basis of the existence of incongruous counterparts (such as a left and a right hand, or any asymmetrical object and its mirror-image). The clear, intrinsic difference between a left hand and a right hand, Kant claimed, cannot be understood on a relational view of (...) space - for in terms of the spatial relations of their parts, there is no difference to be found. Kant's argument has been interpreted by, among others, Graham Nerlich (in 1973, Hands, Knees and Absolute Space, The Journal of Philosophy). I briefly discuss Nerlich, and then offer a different reconstruction of the argument, one that appears to be closer to Kant's text. The reconstruction, however, essentially involves ascription of primitive identity to parts of space. Comparing the Kantian absolutist account of incongruous counterparts using primitive identity to the correct relationist account, I conclude that the absolutist account pays a heavy metaphysical price, without buying any genuine explanatory advantage over the relationist. I go on to examine recent suggestions that parity-non-conservation phenomena in quantum physics allow a stronger version of Kant's challenge to relationism. On closer examination, it turns out that here too the absolutist or substantivalist must be appealing to space parts with primitive identity in order to claim an advantage over relationists; and here too, I argue the substantivalist story really has no advantage over the correct relationist account. (shrink)

BackgroundResponsive neurostimulation has been utilized as a treatment for intractable epilepsy. The RNS System delivers stimulation in response to detected abnormal activity, via leads covering the seizure foci, in response to detections of predefined epileptiform activity with the goal of decreasing seizure frequency and severity. While thalamic leads are often implanted in combination with cortical strip leads, implantation and stimulation with bilateral thalamic leads alone is less common, and the ability to detect electrographic seizures using RNS System thalamic leads is (...) uncertain.ObjectiveThe present study retrospectively evaluated fourteen patients with RNS System depth leads implanted in the thalamus, with or without concomitant implantation of cortical strip leads, to determine the ability to detect electrographic seizures in the thalamus. Detailed patient presentations and lead trajectories were reviewed alongside electroencephalographic analyses.ResultsAnterior nucleus thalamic leads, whether bilateral or unilateral and combined with a cortical strip lead, successfully detected and terminated epileptiform activity, as demonstrated by Cases 2 and 3. Similarly, bilateral centromedian thalamic leads or a combination of one centromedian thalamic alongside a cortical strip lead also demonstrated the ability to detect electrographic seizures as seen in Cases 6 and 9. Bilateral pulvinar leads likewise produced reliable seizure detection in Patient 14. Detections of electrographic seizures in thalamic nuclei did not appear to be affected by whether the patient was pediatric or adult at the time of RNS System implantation. Sole thalamic leads paralleled the combination of thalamic and cortical strip leads in terms of preventing the propagation of electrographic seizures.ConclusionThalamic nuclei present a promising target for detection and stimulation via the RNS System for seizures with multifocal or generalized onsets. These areas provide a modifiable, reversible therapeutic option for patients who are not candidates for surgical resection or ablation. (shrink)

This article highlights a use of analogies in science that so far has received relatively little systematic discussion: providing reasons for pursuing a model or theory. Using the development of the liquid drop model as a test case, I critically assess two extant pursuit worthiness accounts: that analogies justify pursuit by supporting plausibility arguments and that analogies can serve as a guide to potential theoretical unification. Neither of these fit the liquid drop model case. Instead, I develop an alternative account, (...) based on the idea that analogies facilitate the transfer of a well-understood modelling strategy to a new domain. 1Introduction2Case Study: The Development of the Liquid Drop Model3Plausibility Accounts 3.1Bartha on plausibility and analogical inference3.2Plausibility and the drop analogy4Analogies as a Guide to Unification5Generative Accounts 5.1Analogy-based modelling strategies5.2Did analogies play a merely generative role?6A New Pursuit Worthiness Account of Analogies 6.1Transferring understanding-with through analogies6.2Understanding-with and the liquid drop model7Conclusion. (shrink)

Fluorescence microscopy has provided a route to qualitatively analyze features of nuclear structures and chromatin domains with increasing resolution. However, it is becoming increasingly important to develop tools for quantitative analysis. Here, we present an automated method to quantitatively determine the enrichment of several endogenous factors, immunostained in pericentric heterochromatin domains in mouse cells. We show that this method permits an unbiased characterization of changes in the enrichment of several factors with statistical significance from a large number of nuclei. (...) Furthermore, the nuclei can be sorted according to the enrichment value of these factors. This method should prove useful to monitor events related to changes in the amount, rather than the presence or absence, of any factor. By adapting a few parameters, it could be extended to other nuclear structures and the benefit of using available software will permit its use in many biological labs. (shrink)

Ethical justification for clinical research may invoke equipoise, an element of scientific uncertainty regarding the superior choice if presented with different therapeutic options. Given a relativ...

We describe how the choice of an appropriate (“physical”) gauge leads to the solution of a nonperturbative problem in quantum electrodynamics: dynamical chiral symmetry breaking in QED in a constant magnetic field.