An extension of the hypothetical experiment of Szilard, which involved the action of a one-molecule gas in an isolated isothermal system, is developed to illustrate how irreversibility may arise out of Brownian motion. As this development requires a consideration of nonmolecular components such as wheels and pistons, the thought-experiment is remodeled in molecular terms and appears to function as a perpetuum mobile.

A particle of molecular dimensions which can exist in two states is associated with a membrane pore through which molecules of a gas can pass. The gas molecules from two identical phases on either side of the membrane may pass only when the particle is in one particular state. If certain restrictions are imposed on the system, then the particle appears to act like a Maxwell's Demon(1) which “handles” the gas molecules during their passage through the pore.

Live donor kidney transplantation is the best treatment option for most patients with late-stage chronic kidney disease; however, the rate of living kidney donation has declined in the United States. A consensus conference was held June 5-6, 2014 to identify best practices and knowledge gaps pertaining to live donor kidney transplantation and living kidney donation. Transplant professionals, patients, and other key stakeholders discussed processes for educating transplant candidates and potential living donors about living kidney donation; efficiencies in the living donor (...) evaluation process; disparities in living donation; and financial and systemic barriers to living donation. We summarize the consensus recommendations for best practices in these educational and clinical domains, future research priorities, and possible public policy initiatives to remove barriers to living kidney donation. (shrink)

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into (...) two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop. (shrink)

Die Frequenzkurven, die die lebendige Substanz charakterisieren, können als eine statische Beschreibung oder als das Ergebnis einer Entwicklung betrachtet werden.Im ersten Falle akzeptiert man ohne weiteres die gegebenen Verteilungen und man versucht, ihnen durch mathematische Gleichungen, die keine unmittelbare Wirklich-keitsbedeutung haben, nahezukommen. Das kausale Denken wird hier ausgeschaltet oder man gibt sich wenigstens mit nur sehr groben Analogien zufrieden.Verschiedene Methoden über die Genese der Frequenzkurven werden besprochen; dabei wird gezeigt, dass die Mehrheit der Fälle auf Hypothesen beruht, die biologisch wenig (...) begründet sind. Eine Ausnahme davon macht die Theorie vonJ. C. Kapteyn, weil er den Vorgang des Wachstums in die Genese einbezieht. Seine Methode weiter ausbauend kann man sich vorstellen, dass die Genese einer Frequenzkurve in erblich homogenem Pflanzenmaterial durch Variation der Wachstumsgeschwindigkeit zustandekommt.Auf solche Weise kann man in einem Koordinatensystem mit Länge und Zeit als Koordinaten ein “Deviationsraster” konstruieren.In einem experimentell untersuchten Fall ergab die graphische Methode mit völlig ausreichender Genauigkeit die schon gefundene Frequenz.Les courbes de fréquence qui caractérisent la matière vivante, peuvent être considérées ou comme une description statique ou bien comme le produit d'un développement.Dans le premier cas on accepte les distributions obtenues et on essaie de s'en rapprocher par des équations mathématiques qui n'ont pas une réalité effective. On ne recherche plus la causalité ou alors on se contente le plus souvent d'analogies très grossières.Les auteurs traitent des diverses méthodes de la genèse des courbes de fréquence et démontrent que la plupart des cas reposent sur des hypothèses qui ont peu de fond biologique. La théorie deM. J. C. Kapteyn fait exception parcequ'il introduit le processus de croissance dans la genèse. En poursuivant plus loin dans sa méthode on peut se figurer que la genèse d'une courbe de fréquence de plantes homogènes par hérédité s'expliquerait par des variations de vitesse de croissance.De cette façon on peut construire une “grille de déviation” dans un système en prenant longueur et temps comme coordonnées.Dans un cas essayé expérimentalement ce graphique donnait avec une exactitude assez grande la distribution de fréquence déjà trouvée. (shrink)

We report the identification of a recurrent, 520-kb 16p12.1 microdeletion associated with childhood developmental delay. The microdeletion was detected in 20 of 11,873 cases compared with 2 of 8,540 controls and replicated in a second series of 22 of 9,254 cases compared with 6 of 6,299 controls. Most deletions were inherited, with carrier parents likely to manifest neuropsychiatric phenotypes compared to non-carrier parents. Probands were more likely to carry an additional large copy-number variant when compared to matched controls. The clinical (...) features of individuals with two mutations were distinct from and/or more severe than those of individuals carrying only the co-occurring mutation. Our data support a two-hit model in which the 16p12.1 microdeletion both predisposes to neuropsychiatric phenotypes as a single event and exacerbates neurodevelopmental phenotypes in association with other large deletions or duplications. Analysis of other microdeletions with variable expressivity indicates that this two-hit model might be more generally applicable to neuropsychiatric disease. © 2010 Nature America, Inc. All rights reserved. (shrink)

The paper is concerned with explaining some of the principal theoretical developments in elementary particle physics and discussing the associated methodological problems both in respect of heuristics and appraisal. Particular reference is made to relativistic quantum field theory, renormalization, Feynman diagram techniques, the analytic S-matrix and the Chew — Frautschi bootstrap.

The volume also publishes for the first time a part of his Debrecen Ph.D. thesis and it is concluded by a bibliography of his Hungarian writings.

Recent discussions of experimental tests of the Sum Rule have been carried out in the context of the special circumstances attending the Cross-Ramsey experiment. A more general analysis of possible tests is presented. A technical mistake of Fine and Glymour concerned with a misunderstanding of the physics of the Cross-Ramsey experiment is explained and a detailed analysis of a thought experiment based on the Einstein-Podolsky-Rosen wave function is given. It is concluded, in agreement with Fine, that scattering experiments do not (...) test the Sum Rule as a principle which supplements standard quantum mechanics. (shrink)

Many years ago, when Michael was lecturing in Oxford on the Philosophy of Physics and was trying to explain the logic of Aspect's experiments in Paris, he turned to me to expound the correct doctrine of counter-factual truth. I was flummoxed. It had been much discussed in late- and postmediaeval times, especially in the Iberian peninsula, and had recently enjoyed a revival in the Eastern United States. But Middle Knowledge, as the Schoolmen called it, was beyond my comprehension, and I (...) could only exemplify once again the truism that philosophers were better at raising problems than resolving them. (shrink)

In his paper, “Grand Unified Gauge Theories and the Number of Elementary Particles,“ Robert Weingard suggests what he calls the Extended Redhead's Principle for elementary particles: “Two particles for which there are conceivable circumstances in which one can be ‘rotated’ or reoriented into the other are the same particles”. The philosophical soundness of such a principle is questionable.

Objective The UK Human Papillomavirus (HPV) vaccine programme commenced in the autumn of 2008 for year 8 (age 12–13 years) schoolgirls. We examine whether the vaccine should be given when there is a difference of opinion between daughters and parents or guardians. Design Qualitative study using semi-structured interviews. Participants A sample of 25 stakeholders: 14 professionals involved in the development of the HPV vaccination programme and 11 professionals involved in its implementation. Results Overriding the parents' wishes was perceived as problematic (...) and could damage the relationship between school and parents. A number of practical problems were raised in relation to establishing whether parents were genuinely against their daughter receiving the vaccine. Although many respondents recognised that the Gillick guidelines were relevant in establishing whether a girl could provide consent herself, they still felt that there were significant problems in establishing whether girls could be assessed as Gillick competent. In some areas school nurses had been advised not to give the vaccine in the absence of parental consent. None of the respondents suggested that a girl should be vaccinated against her consent even if her parents wanted her to have the vaccine. Conclusions While the Gillick guidelines provide a legal framework to help professionals make judgements about adolescents consenting to medical treatment, in practice there appears to be variable and confused interpretation of this guidance. Improved legal structures, management procedures and professional advice are needed to support those who are assessing competence and establishing consent to vaccinate adolescents in a school setting. (shrink)

In their 1993 article "'Theoretical Mathematics': Toward a Cultural Synthesis of Mathematics and Theoretical Physics" published in the Bulletin of the American Mathematical Society, the eminent mathematical physicists Arthur Jaffe and Frank Quinn proposed a set of prescriptions for the interaction between mathematicians and theoretical physicists that should foster mathematicians' receptivity of ideas from physics by safeguarding mathematical rigour against uncontrolled speculation. The proposal propelled and intensive debate in the Bulletin and lead to a special issue of the journal Synthese. (...) So far, however, philosophers of science have hardly addressed this debate, perhaps because it lacks a systematic framework. In this contribution I portray the various stances taken in the Jaffe-Quinn debate from the perspective of Imre Lakatos philosophy of mathematics that seems most suitable for a debate concerning mathematical growth. After outlining the lessons to be drawn for it from Lakatos's published works, I examine which modifications of Lakatos's account are in place to enable a fruitful assessment of present mathematical physics in which axiomatization plays a key role. (shrink)