Nature's simplest atom and mother of all matter, hydrogen feeds the stars as well as interlaces the molecules of their biological descendants – to whom it ultimately whispers the secrets of quantum reality. Hydrogen’s most prevalent earthly guise lies within the composition of water. A slight electrical disturbance can split water into hydrogen and oxygen gas, resulting in diaphanous bubble clouds slowly rising towards the liquid’s surface. Though the founding fathers of electrochemistry posited that the mass of liberated bubbles is (...) directly proportional to the input voltage, certain modes of electrolysis release more energy than is spent. One such mode involves water’s Janus-faced capacity to react as either an acid or a base. Emanating from an array of electrodes at the bottom of a water-filled chamber, strings and strata of hydrogen bubbles meticulously trace their emergent surroundings. In addition to eddy formations incited by a bubble's rapid growth and subsequent detachment from the electrode surface, acoustic vibrations permeate the two-phase fluid. As the sonic frequency and amplitude rises, the hydrogen bubbles start to coalesce with one another. When the sound field reaches maximum intensity, it can trap bubbles within its antinodes. The vibrations are generated both by transducers and by the bubbles themselves, which emit frequencies ranging from the audible spectrum to as high as 800 kHz. A white laser sheet scans and illuminates the hydrogen bubble trajectories. Each quivering bubble-lens divides the white light into its constituent spectrum of colors. While scanning, the laser sheet also swiftly pulsates and thereby extends the perceivable resolution of micro-momentary bubble dynamics. Before it even begins to map out its vibratory environment, a bubble goes through various stages of spatio-temporal evolution. During the first phase of growth, a bubble nucleus inflates linearly with time. At the second stage, bubble growth is limited by the diffusion of gas within the liquid, causing its size to increase as the square root of time. The final phase before detachment is limited by the kinetics of dissolved gas production, causing the bubble to grow as the cube root of time.1 Beyond macroscopically observable bubbles, an expanse of nanobubbles hides within the water’s internal architecture. Some researchers presume that these nanobubbles of dissolved gas are the carriers of water’s magnetic ‘memory’, enabling electromagnetic fields to saturate its innards for hours and even days after their initial appearance. In the seas and oceans, the lingering presence of electromagnetic fields photonically imparted by sunlight, triggers the electrolysis responsible for most of the Earth’s hydrogen. An essential form of photosynthesis, solar water splitting is the cleanest and most efficient means imaginable for generating and storing energy. —Evelina Domnitch & Dmitry Gelfand *** Animals and plants are formed in earth and in water because there is water in earth, and there is pneuma in water, and there is soul heat in all pneuma ; so that in a way all things are full of soul. Hence plants and animals quickly form once this gets enclosed; and when this enclosing happens, when the corporeal liquids get heated, a sort of frothy bubble is formed. Now the difference between the various creatures which are produced in this way are due to the stuff which makes up the envelope around the soul-source.2 Throwing light into this pneumatic spray of perdurances, which would otherwise swarm below the threshold of human visibility, Evelina Domnitch and Dmitry Gelfand’s Hydrogeny saturates the viewer’s sensorial space with the nano-architectures of froth. Straddling the cell wall between scientific enquiry and artistic praxis, Hydrogeny , beckons a recasting of Lucretius' clinamen in tune with the technologies of the modern observer. For Lucretius it was the indeterminate swerving of an atomistic layer of reality which accounted for the unpredictability of change and the existence of free will. Taken up by Harold Bloom to describe the swerving of cultural production from that which has already been made, the idea has since been textually redressed by Lacan, Derrida, Serres, Deleuze, Nancy, and Badiou. Here we have been given a kaleidoscopic technique for refining and expanding awareness of our enmeshment with so many nested, atomistic layers of object-bubbles—of things—as Aristotle might say,“full of soul.” The gravitational pull of Hydrogeny ushers a de-centered human spectatorship to the ever more intimate recesses of what media philosopher N. Katherine Hayles calls our capacity for “deep attention.”3 Vaporous attention suspended and re-oriented. Microscopic as these diaphanous waves are, the calling they produce is anything but inconsequential. Evelina Domnitch and Dmitry Gelfand are two-thirds of the Amsterdam-based Art–Science Labratory, Optofonica , an atelier initiated by the Italian interdisciplinary artist TeZ in 2006. Follow more of their work at www.portablepalace.com —Isaac Linder NOTES (1) cf. Brandon, Kelsall, Levine, & Smith. “Interfacial Electrical Properties of Electrogenerated Bubbles.” Journal of Applied Electrochemistry 15 (1985):485-493. (2)Aristotle, On the Generation of Animals, 762a18, tr. A. L. Peck (Cambridge, MA: Loeb Classical Library, 1942). (3)“ My article on hyper and deep attention ,” N. Katherine Hayles, accessed on September 14, 2011. (shrink)

IntroductionSimilarities in morphology, physiological function, and neurophysiological findings between median and ulnar nerves are not unequivocal. Our previous study confirmed differences in motor fiber parameters between these nerves in healthy persons. We made an attempt to assess and compare the physiological parameters of different sensation modalities in median and ulnar nerves.MethodsThe study was performed in 31 healthy, right-handed volunteers: 17 women, 14 men, mean age 44.8 ± 15.5 years. Standard sensory conduction tests in the median and ulnar nerves were performed (...) together with the estimation of vibratory, temperature, and warm- and cold-induced pain thresholds in the C7 and C8 dermatomes on the palm, using quantitative sensory testing.ResultsThere were no statistically significant differences in the standard sensory conduction test in the median and ulnar nerves across the whole group: between right and left hands, and between women and men. We revealed differences in the temperature and pain thresholds between these nerves, mainly in low temperature perception. There were no differences in estimated thresholds between sides or in female and male groups. The vibratory limits did not differ significantly between nerves, and subgroups.ConclusionThe study confirmed the differences in the physiological sensory perception between the median and ulnar nerves. The median nerve is more sensitive to temperature stimulation than the ulnar nerve, but simultaneously less sensitive to pain-inducing temperature stimuli. These findings should be considered during the examination of hand nerve pathology. (shrink)

Vibratory Modernism" is a collection of original essays that will enable scholars and students to explore how vibrations provided a means of bridging science and art -- two fields that became increasingly separate over the course of the nineteenth and early twentieth centuries. The book demonstrates the vital role played by vibrations in the fields of physics, physiology, spiritualism, and by new vibratory technologies, in helping to shape the way modernist art was made and viewed. The chapters are (...) placed into three connecting parts focusing on literature, the visual arts and theatre, each part highlighting the diverse ways in which writers, artists and performers engaged with the fascinating world of vibrations. (shrink)

Despite the prominence of thresholds in theories of distributive justice, there is no general account of what sort of role is played by the idea of a threshold within such theories. This has allowed an ongoing lack of clarity and misunderstanding around views that employ thresholds. In this article, I develop an account of the concept of thresholds in distributive justice. I argue that this concept contains three elements, which threshold views deploy when ranking possible distributions. These elements (...) are (i) the level of the threshold, (ii) what constitutes the value of the threshold, and (iii) how benefits above and below the threshold must be allocated. I highlight three contributions that this particular account of thresholds makes: it clarifies the nature of the shift that occurs at the threshold; it resolves a common misunderstanding about headcount principles; and it shows how the arbitrariness objection can be met. (shrink)

The threshold problem is the task of adequately answering the question: “Where does the threshold lie between knowledge and lack thereof?” I start this paper by articulating two conditions for solving it. The first is that the threshold be neither too high nor too low; the second is that the threshold accommodate the significance of knowledge. In addition to explaining these conditions, I also argue that it is plausible that they can be met. Next, I argue (...) that many popular accounts of knowledge cannot meet them. In particular, I lay out a number of problems that standard accounts of knowledge face in trying to meet these conditions. Finally, near the end of this paper, I argue that there is one sort of account that seems to evade these problems. This sort of account, which is called a cluster account of knowledge, says that knowledge is to be accounted for in terms of truth, belief and a cluster of epistemic properties and also that knowledge doesn’t require having all members of the cluster, but merely some subset. (shrink)

Despite the prominence of thresholds and limits in theories of distributive justice, there is no general account of their role within such theories. This has allowed an ongoing lack of clarity and misunderstanding around threshold views in distributive justice. In this thesis, I develop an account of the conceptual structure of such views. Such an account helps understand and characterize threshold views, can subsume what may seem to be different debates about such views under one conceptual header, and (...) can be used to further examine and develop patterns of justice that draw on thresholds. In light of this account, I propose a novel characterization of sufficientarianism which sheds new light on the distinctiveness of sufficientarianism as a distributive principle and on the common objections to sufficientarianism. Moreover, I examine and defend limitarianism, which is the view that people should not have more than a certain amount of wealth. In particular, I argue in favour of limitarianism as a midlevel principle for guiding institutional design and individual actions and, furthermore, as a specification of what a just allocation of wealth requires under epistemic constraints. (shrink)

The Threshold of the Visible World advances a revolutionary new political aesthetic--Kaja Silverman explores the possibilities for looking beyond the restrictive mandates of the self, and the normative aspects of the cultural image-repertoire. She provides a detailed account of the social and psychic forces which constrain us to look and identify in normative ways, and the violence which that normativity implies. Accounting for these phenomena on both a conscious and an unconcious level, Silverman analyzes the psychic and textual conditions (...) under which our "field of vision" can be expanded. The title of this book is taken from Lacan's essay on the mirror stage. In that text, Lacan writes that "the mirror-image would seem to be the threshold of the visible world." He thereby suggests that the visible world has no existence as such until the infant subject has access to an image of self. Lacan intimates that the mirror provides the frame through which one relates to others within the domain of vision, stressing the priority of narcissism and the ego over all other libidinal transactions. The Threshold of the Visible World provides a psychic, social and political specification of Lacan's claim, and most particularly of its implications for the subject's relations to the social other. This is accomplished through examination of the ego, as well as two other categories at the center of Lacan's account of the mirror stage: ideality and identification. This book is an ethical-political project which leads to the re-elaboration of a number of crucial theoretical categories--Silverman offers an account of the bodily ego, of identification, of idealization, of the gaze, of the look, and of the "photographic." The Threshold of the Visible World leads as well to the formulation of a fresh model for conceptualizing sexual, racial and class "difference," and the terms under which it might be dismantled. This book thus seeks to apprehend the field of vision through the frame of a different kind of bodily ego, and discover the pleasures to be derived from corporeal transport. (shrink)

Mental-threshold egalitarianism, well-known examples of which include Jeff McMahan’s two-tiered account of the wrongness of killing and Tom Regan’s theory of animal rights, divides morally considerable beings into equals and unequals on the basis of their individual mental capacities. In this paper, I argue that the line that separates equals from unequals is unavoidably arbitrary and implausibly associates an insignificant difference in empirical reality with a momentous difference in moral status. In response to these objections, McMahan has proposed the (...) introduction of an intermediate moral status. I argue that this move ultimately fails to address the problem. I conclude that, if we are not prepared to give up moral equality, our full and equal moral status must be grounded in a binary property that is not a threshold property. I tentatively suggest that the capacity for phenomenal consciousness is such a property, and a plausible candidate. (shrink)

This paper provides an axiomatic analysis of sufficientarian social evaluation. Sufficientarianism has emerged as an increasingly important notion of distributive justice. We propose a class of principles that we label generalized critical-level sufficientarian orderings. The distinguishing feature of our new class is that its members exhibit constant critical levels of well-being that are allowed to differ from the threshold of sufficiency. Our basic axiom assigns priority to those below the threshold, a property that is shared by numerous other (...) sufficientarian approaches. When combined with the well-known strong Pareto principle and the assumption that there be a constant critical level, the axiom implies that the critical level cannot be below the threshold. The main results of the paper are characterizations of our new class and an important subclass. As a final observation, we identify the generalized critical-level sufficientarian orderings that permit us to avoid the repugnant conclusion and the sadistic conclusion, which are known as two fundamental challenges in population ethics. (shrink)

A small consortium of philosophers has begun work on the implications of epistemic networks (Zollman 2008 and forthcoming; Grim 2006, 2007; Weisberg and Muldoon forthcoming), building on theoretical work in economics, computer science, and engineering (Bala and Goyal 1998, Kleinberg 2001; Amaral et. al., 2004) and on some experimental work in social psychology (Mason, Jones, and Goldstone, 2008). This paper outlines core philosophical results and extends those results to the specific question of thresholds. Epistemic maximization of certain types does show (...) clear threshold effects. Intriguingly, however, those effects appear to be importantly independent from more familiar threshold effects in networks. (shrink)

How, and how well, do people switch between exploration and exploitation to search for and accumulate resources? We study the decision processes underlying such exploration/exploitation trade‐offs using a novel card selection task that captures the common situation of searching among multiple resources (e.g., jobs) that can be exploited without depleting. With experience, participants learn to switch appropriately between exploration and exploitation and approach optimal performance. We model participants' behavior on this task with random, threshold, and sampling strategies, and find (...) that a linear decreasing threshold rule best fits participants' results. Further evidence that participants use decreasing threshold‐based strategies comes from reaction time differences between exploration and exploitation; however, participants themselves report non‐decreasing thresholds. Decreasing threshold strategies that “front‐load” exploration and switch quickly to exploitation are particularly effective in resource accumulation tasks, in contrast to optimal stopping problems like the Secretary Problem requiring longer exploration. (shrink)

If you believe that there are restrictions on what we as moral agents can do to others, but that these restrictions can give way in the face of competing considerations, then you believe in thresholds for rights. In this dissertation I develop an account of thresholds for rights, in defence of a position which is often stated but rarely explained or defended. I begin with the obvious question: How much needs to be at stake before a right's claim is overridden? (...) ;Less obvious, but equally crucial, are questions about the distribution of the total which needs to be at stake. After developing a framework for answering that question, in subsequent chapters I deal with other factors which may influence our judgements about the overridability of rights' claims, including the numbers and identities of the agents involved. (shrink)

Binarizing belief aggregation tackles the problem of aggregating individuals’ probabilistic beliefs on logically connected propositions into the group’s binary beliefs. One common approach to associating probabilistic beliefs with binary beliefs would be applying thresholds to probabilities. This paper aims to introduce and classify a range of threshold-based binarizing belief aggregation rules while characterizing them based on different forms of monotonicity and other properties.

Application of egalitarian and prioritarian accounts of health resource allocation in low‐income countries have both been criticized for implying distribution outcomes that allow decreasing/undermining health gains and for tolerating unacceptable standards of health care and health status that result from such allocation schemes. Insufficient health care and severe deprivation of health resources are difficult to accept even when justified by aggregative efficiency or legitimized by fair deliberative process in pursuing equality and priority oriented outcomes. I affirm the sufficientarian argument that, (...) given extreme scarcity of public health resources in low‐income countries, neither health status equality between populations nor priority for the worse off is normatively adequate. Nevertheless, the threshold norm alone need not be the sole consideration when a country's total health budget is extremely scarce. Threshold considerations are necessary in developing a theory of fair distribution of health resources that is sensitive to the lexically prior norm of sufficiency. Based on the intuition that shares must not be taken away from those who barely achieve a minimal level of health, I argue that assessments based on standards of minimal physical/mental health must be developed to evaluate the sufficiency of the total resources of health systems in low‐income countries prior to pursuing equality, priority, and efficiency based resource allocation. I also begin to examine how threshold sensitive health resource assessment could be used in the Philippines. (shrink)

When should doctors seek protective custody to override a parent’s refusal of potentially lifesaving treatment for their child? The answer to this question seemingly has different answers for different subspecialties of pediatrics. This paper specifically looks at different thresholds for physicians overriding parental refusals of life-sustaining treatment between neonatology, cardiology, and oncology. The threshold for mandating treatment of premature babies seems to be a survival rate of 25–50%. This is not the case when the treatment in question is open (...) heart surgery for a child with congenital heart disease. Most cardiologists would not pursue legal action when parents refuse treatment, unless the anticipated survival rate after surgery is above 90%. In pediatric oncology, there are case reports of physicians requesting and obtaining protective custody for cancer treatment when the reported mortality rates are 40–50%. Such differences might be attributed to differences in care, a reasonable prioritization of quality of life over survival, or the role uncertainty plays on prognoses, especially for the extremely young. Nonetheless, other, non-medical factors may have a significant effect on inconsistencies in care across these pediatric subspecialties and require further examinations. (shrink)

John McCumber; The Threshold of Bio-Ethics: Philosophical Warrant in the Thought of Stephen Erickson, Christian bioethics: Non-Ecumenical Studies in Medical Mor.

In this article, I propose a novel characterization of sufficientarianism. I argue that sufficientarianism combines three claims: a priority claim that we have non-instrumental reasons to prioritize benefits in certain ranges over benefits in other ranges; a continuum claim that at least two of those ranges are on one continuum; and a deficiency claim that the lower a range on a continuum, the more priority benefits in that range have. This characterization of sufficientarianism sheds new light on two long-standing philosophical (...) debates, namely about the distinctiveness of sufficientarianism as a distributive principle and about the common objections to sufficientarianism. (shrink)

_Threshold Concepts in Problem-based Learning_ provides a critical discussion and guidance for educational researchers, teachers, innovators and policy makers wanting to explore the interrelationship of PBL and threshold concepts.

This note is part of the implementation of a programme in foundations of mathematics to find exact threshold versions of all mathematical unprovability results known so far, a programme initiated by Weiermann. Here we find the exact versions of unprovability of the finite graph minor theorem with growth rate condition restricted to planar graphs, connected planar graphs and graphs embeddable into a given surface, assuming an unproved conjecture : ‘there is a number a>0 such that for all k≥3, and (...) all n≥1, the proportion of connected graphs among unlabelled planar graphs of size n omitting the k-element circle as minor is greater than a’. Let γ be the unlabelled planar growth constant . Let P be the following first-order arithmetical statement with real parameter c: “for every K there is N such that whenever G1,G2,…,GN are unlabelled planar graphs with Gishrink)

Categorical perception (CP) is said to occur when a continuum of equally spaced physical changes is perceived as unequally spaced as a function of category membership (Harnad, S. (Ed.) (1987). Psychophysical and cognitive aspects of categorical perception: A critical overview. Cambridge: Cambridge University Press). A common suggestion is that CP for color arises because perception is qualitatively distorted when we learn to categorize a dimension. Contrary to this view, we here report that English speakers show no evidence of lowered discrimination (...) thresholds at the boundaries between blue and green categories even though CP is found at these boundaries in a supra-threshold task. Furthermore, there is no evidence of different discrimination thresholds between individuals from two language groups (English and Korean) who use different color terminology in the blue-green region and have different supra-threshold boundaries. Our participants' just noticeable difference (JND) thresholds suggest that they retain a smooth continuum of perceptual space that is not warped by stretching at category boundaries or by within-category compression. At least for the domain of color, categorical perception appears to be a categorical, but not a perceptual phenomenon. (shrink)

The threshold law for N-body fragmentation under dipole forces is formulated. It emerges from the energy dependence of the normalization of the correlated continuum wave function for N fragments. It is shown that the dipole threshold law plays a key role in understanding all threshold fragmentation phenomena since it links the classical threshold law for long-range Coulomb interactions to the statistical law for short-range interactions. Furthermore, a tunnelling mechanism is identified as the common feature which occurs (...) for all three classes of interactions, short-range, dipole and Coulomb. (shrink)

This essay represents a serious but fictional obituary of a scientific concept called the Threshold Dose–Response Model, which has long dominated the fields of toxicology and the broader biomedical sciences. Recent evidence indicates that the Threshold Dose–Response Model has long outlived its utility to predict low‐dose effects. In fact, so poorly does this model predict low‐dose responses that the idea arose that it should receive a symbolic burial recounting its achievements and failings, hence this obituary. BioEssays 29:686–688, 2007. (...) © 2007 Wiley Periodicals, Inc. (shrink)

The continuity thesis of the Poznań school threshold model of the growth of scientific knowledge is considered in the light of the example of Van der Waals' and Boyle-Mariotte's laws. It is argued - using both traditional logical means and the structuralist reconstruction of the example - that the continuity thesis does not hold. A distinction between 'a historical and a systematic point of view' is introduced and it is argued that the continuity thesis of the threshold model (...) presupposes the systematic point of view. However, looking at matters from the systematic point of view need not yield the original theory, looked at from the historical point of view. Applied to the case of Van der Waals/Boyle-Mariotte laws, it turns out that the latter law is not a true idealizing special case of the former, contrary to the continuity thesis. The structuralist analysis of the example indicates that Boyle-Mariotte's law is a false factual law from the historical point of view. However, viewed from the systematic point of view, Boyle-Mariotte's law turns out to be a law which is expandable, adding the relevant new concepts, to an idealized version of Van der Waals' law. This idealizing version of Van der Waal's law in turn is a structuralist specialization of the (general) Van der Waals' law. (shrink)

A dynamic threshold, which controls the nature and course of learning, is a pivotal concept in Page's general localist framework. This commentary addresses various issues surrounding biologically plausible implementations for such thresholds. Relevant previous research is noted and the particular difficulties relating to the creation of so-called instance representations are highlighted. It is stressed that these issues also apply to distributed models.

This paper shows that so-called ‘threshold concepts’ have been defined in a way that makes it impossible, even in principle, to empirically isolate them. It continues by proposing an alternative theoretical framework, and argues: (1) that concepts are not reducible to abilities; (2) that acquisition of a given concept can be necessary, but not sufficient, for the possession of an ability; and (3) that being ‘threshold’ is an extrinsic property, such that what is threshold for one person (...) is not for another. It closes by outlining two resultant problems for related empirical research. First, how is it possible to test for concepts, rather than abilities? Second, how can we tell if there is more than one possible conceptual route to the same ability? (shrink)

In this paper we study changes of beliefs in a ranking-theoretic setting using non-extremal implausibility thresholds for belief. We represent implausibilities as ranks and introduce natural rank changes subject to a minimal change criterion. We show that many of the traditional AGM postulates for revision and contraction are preserved, except for the postulate of Preservation which is invalid. The diagnosis for belief contraction is similar, but not exactly the same. We demonstrate that the one-shot versions of both revision and contraction (...) can be represented as revisions based on semiorders, but in two subtly different ways. We provide sets of postulates that are sound and complete in the sense that they allow us to prove representation theorems. We show that, and explain why, the classical duality between revision and contraction, as exhibited by the Levi and Harper identities, is partly broken by threshold-based belief changes. We also study the logic of iterated threshold-based revision and contraction. The traditional Darwiche-Pearl postulates for iterated revision continue to hold, as well as two additional postulates that characterize ranking-based revision as a restricted `improvement' operator. We investigate the dual notion of iterated threshold-based belief contraction and provide a new set of postulates for it, characterizing contraction as a restricted 'degrading' operator. (shrink)

Various types of plant species have been extensively used for heavy metals phyto-remediation without taking into consideration its tolerance threshold. In this study, Vetiver grass, Vetiveria zizanioides (Linn.) Nash was evaluated under five different sets of contaminated spiked cadmium (5Cd, 10Cd, 50Cd, 100Cd and 150Cd mg/kg) and lead (50Pb, 100Pb, 200Pb, 400Pb and 800Pb mg/kg) concentration levels in soil. The growth performance, metal tolerance and phyto-assessment of Cd and Pb in the roots and tillers were assessed using flame atomic (...) absorption spectrometry (FAAS). Tolerance index (TI), translocation factor (TF), biological transfer factor (BTF), biological accumulation coefficient (BAC) and metal uptake efficacy were used to determine the Cd and Pb translocation capability in Vetiver grass. Significantly higher (p<0.05) accumulation of Cd and Pb was recorded in the roots of all spiked treatments. Furthermore, strong and significantly positive correlations were exhibited between the increased levels of spiked heavy metal concentrations with both Cd (r=0.975) and Pb (r=0.952) accumulations. The results of this study showed Vetiver grass as an effective phyto-stabilizer for both Cd and Pb. Nevertheless, the growth of Vetiver grass was restricted when the tolerance threshold of 100 mg/kg (dry weight basis) Cd was exceeded in the contaminated soil. (shrink)

According to an increasingly popular view in epistemology and philosophy of mind, beliefs are sensitive to contextual factors such as practical factors and salient error possibilities. A prominent version of this view, called credal sensitivism, holds that the context-sensitivity of belief is due to the context-sensitivity of degrees of belief or credence. Credal sensitivism comes in two variants: while credence-one sensitivism (COS) holds that maximal confidence (credence one) is necessary for belief, threshold credal sensitivism (TCS) holds that belief consists (...) in having credence above some threshold, where this threshold doesn’t require maximal confidence. In this paper, I argue that COS has difficulties in accounting for three important features about belief: i) the compatibility between believing p and assigning non-zero credence to certain error possibilities that one takes to entail not-p, ii) the fact that outright beliefs can occur in different strengths, and iii) beliefs held by unconscious subjects. I also argue that TCS can easily avoid these problems. Finally, I consider an alleged advantage of COS over TCS in terms of explaining beliefs about lotteries. I argue that lottery cases are rather more problematic for COS than TCS. In conclusion, TCS is the most plausible version of credal sensitivitism. (shrink)

_Threshold Concepts on the Edge_ explores new directions in threshold concept research and practice and is of relevance to teachers, learners, educational researchers and academic developers.

We applaud Notini and colleagues for highlighting the clinical and ethical complexities of a case in which a non-binary individual desires indefinite treatment with puberty blockers.1 While we agree discontinuing treatment may cause psychological distress, we believe there are potential physical and neurocognitive harms caused by prolonged treatment that have been underestimated given the limited research conducted to date. Specifically, the impact of permanent pubertal suppression on the brain and decision-making capacity should be considered. In this context, we outline the (...) potential risks of ongoing pubertal suppression on bone and cardiovascular health, sexual and reproductive function, and brain development—all noted in the article but perhaps in an overly simplistic manner.1 First, the authors’ note OPS will almost certainly result in reduced bone density.1 Although we agree the absolute fracture risk is low in studies among older adults, there is less clarity about implications during adolescence and young adulthood when peak bone accrual occurs.2 Further, the authors propose ongoing monitoring with bone density scans, but no clear guidelines for clinicians if bone density becomes critically low—so we ask, at what point would a potential fracture risk outweigh the proposed benefits …. (shrink)

We applaud Notini and colleagues for highlighting the clinical and ethical complexities of a case in which a non-binary individual desires indefinite treatment with puberty blockers. 1 While we agree discontinuing treatment may cause psychological distress, we believe there are potential physical and neurocognitive harms caused by prolonged treatment that have been underestimated given the limited research conducted to date. Specifically, the impact of permanent pubertal suppression on the brain and decision-making capacity should be considered. In this context, we outline (...) the potential risks of ongoing pubertal suppression on bone and cardiovascular health, sexual and reproductive function, and brain development—all noted in the article but perhaps in an overly simplistic manner. 1 First, the authors’ note OPS will almost certainly result in reduced bone density. 1 Although we agree the absolute fracture risk is low in studies among older adults, there is less clarity about... (shrink)