1,241 research outputs found
Analytical pair correlations in ideal quantum gases: Temperature-dependent bunching and antibunching
The fluctuation-dissipation theorem together with the exact density response
spectrum for ideal quantum gases has been utilized to yield a new expression
for the static structure factor, which we use to derive exact analytical
expressions for the temperature{dependent pair distribution function g(r) of
the ideal gases. The plots of bosonic and fermionic g(r) display "Bose pile"
and "Fermi hole" typically akin to bunching and antibunching as observed
experimentally for ultracold atomic gases. The behavior of spin-scaled pair
correlation for fermions is almost featureless but bosons show a rich structure
including long-range correlations near T_c. The coherent state at T=0 shows no
correlation at all, just like single-mode lasers. The depicted decreasing trend
in correlation with decrease in temperature for T < T_c should be observable in
accurate experiments.Comment: 8 pages, 1 figure, minor revisio
Is there a reentrant glass in binary mixtures?
By employing computer simulations for a model binary mixture, we show that a
reentrant glass transition upon adding a second component only occurs if the
ratio of the short-time mobilities between the glass-forming component
and the additive is sufficiently small. For , there is no
reentrant glass, even if the size asymmetry between the two components is
large, in accordance with two-component mode coupling theory. For , on the other hand, the reentrant glass is observed and reproduced only by
an effective one-component mode coupling theory.Comment: 4 pages, 3 figure
Reproducibility of lymphovascular space invasion (LVSI) assessment in endometrial cancer
Aims Lymphovascular space invasion (LVSI) in endometrial cancer (EC) is an important prognostic variable impacting on a patient's individual recurrence risk and adjuvant treatment recommendations. Recent work has shown that grading the extent of LVSI further improves its prognostic strength in patients with stage I endometrioid EC. Despite this, there is little information on the reproducibility of LVSI assessment in EC. Therefore, we designed a study to evaluate interobserver agreement in discriminating true LVSI from LVSI mimics (Phase I) and reproducibility of grading extent of LVSI (Phase II). Methods and results Scanned haematoxylin and eosin (H&E) slides of endometrioid EC (EEC) with a predefined possible LVSI focus were hosted on a website and assessed by a panel of six European gynaecological pathologists. In Phase I, 48 H&E slides were included for LVSI assessment and in Phase II, 42 H&E slides for LVSI grading. Each observer was instructed to apply the criteria for LVSI used in daily practice. The degree of agreement was measured using the two-way absolute agreement average-measures intraclass correlation coefficient (ICC). Reproducibility of LVSI assessment (ICC = 0.64, P < 0.001) and LVSI grading (ICC = 0.62, P < 0.001) in EEC was substantial among the observers. Conclusions Given the good reproducibility of LVSI, this study further supports the important role of LVSI in decision algorithms for adjuvant treatment
Acceptabilite´ du test VIH propose´ aux nourrissons dans les services pe´ diatriques, en Coˆ te d’Ivoire, Significations pour la couverture du diagnostic pe´diatrique
Proble`me: Le de´pistage VIH chez les enfants a rarement e´te´ au centre des pre´occupations des chercheurs. Quand le de´pistage pe´diatrique a retenu l’attention, cela a e´te´ pour e´clairer seulement sur les performances diagnostiques en ignorant meˆme que le test pe´diatrique comme bien d’autres peut s’accepter ou se refuser. Cet article met au coeur de son analyse les raisons qui peuvent expliquer qu’on accepte ou qu’on refuse de faire de´pister son enfant.Objectif: Etudier chez les parents, les me`res, les facteurs explicatifs de l’acceptabilite´ du test VIH des nourrissons de moins de six mois.Me´thodes: Entretien semi-directif a` passages re´pe´te´s avec les parents de nourrissons de moins de six mois dans les formations sanitaires pour la pese´e/vaccination et les consultations pe´diatriques avec proposition syste´matique d’un test VIH pour leur nourrisson.Re´sultats: Nous retenons que la re´alisation effective du test pe´diatrique du VIH chez le nourrisson repose sur trois e´le´ments. Primo, le personnel de sante´ par son discours (qui de´note de ses connaissances et perceptions meˆme sur l’infection) oriente´ vers les me`res influence leur acceptation ou non du test. Secundo, la me`re qui par ses connaissances et perceptions meˆme sur le VIH, dont le statut particulier, l’impression de bien-eˆtre chez elle et son enfant influence toute re´alisation du test pe´diatrique VIH. Tertio, l’environnement conjugal de la me`re, particulie`rement caracte´rise´ par les rapports au sein du couple, sur la facilite´ de parler du test VIH et sa re´alisation chez les deux parents ou chez la me`re seulement sont autant de facteurs qui influencent la re´alisation effective du de´pistage du VIH chez l’enfant. Le principe pre´ventif du VIH, et le de´sir de faire tester l’enfant ne suffisent pas a` eux seuls pour aboutir a` sa re´alisation effective, selon certaines me`res confronte´es au refus du conjoint. A l’oppose´, les autres me`res refusant la re´alisation du test pe´diatrique disent s’y opposer ; bien entendu, meˆme dans le cas ou` le conjoint l’accepterait.Discussion: Les me`res sont les principales mises en cause et craignent les re´primandes et la stigmatisation. Le pe`re, le conjoint peut eˆtre un obstacle, quand il s’oppose au test VIH du nourrisson, ou devenir le facilitateur de sa re´alisation s’il est convaincu. Le positionnement du pe`re demeure donc essentiel dans la question de l’acceptabilite´ du VIH pe´diatrique. Les me`res en ont conscience et pre´sagent des difficulte´s a` faire de´pister ou non les enfants sans avis pre´alable du conjoint a` la fois pe`re, et chef de famille.Conclusion: La question du de´pistage pe´diatrique du VIH, au terme de notre analyse, met en face trois e´le´ments qui exigent une gestion globale pour assurer une couverture effective. Ces trois e´le´ments n’existeraient pas sans s’influencer, donc ils sont constamment en interaction et empeˆchent ou favorisent la re´alisation ou non du test pe´diatrique. Aussi, dans une intention d’aboutir a` une couverture effective du de´pistage VIH des nourrissons, faut-il tenir compte d’une gestion harmonieuse de ces trois e´le´ments: La premie`re, la me`re seule (avec ses connaissances, ses perceptions), son environnement conjugal (de proposition du test inte´grant 1- l’e´poux et / ou pe`re de l’enfant avec ses perceptions et connaissances sur l’infection 2- la facilite´ de parler du test et sa re´alisation chez les deux ou un des parents, la me`re) et les connaissances, attitudes et pratiques du personnel de l’e´tablissement sanitaire sur l’infection du VIH.Recommandations: Nos recommandations proposent une rede´finition de l’approche du VIH/sida vers des familles expose´es au VIH et une inte´gration plus accentue´e du pe`re facilitant leur propre acceptation du test VIH et celle de leur enfant.Mots cle´s: Acceptabilite´, Test VIH, Enfants, Nourrissons Problem: HIV testing in children had rarely been a central concern for researchers. When pediatric tracking retained the attention, it was more to inform on the diagnosis tools performances rather than the fact the pediatric test can be accepted or refused. This article highlights the parent’s reasons which explain why pediatric HIV test is accepted or refused.Objective: To study among parents, the explanatory factors of the acceptability of pediatric HIV testing among infant less than six months.Methods: Semi-structured interview with repeated passages in the parents of infants less than six months attending in health care facilities for the pediatric weighing/vaccination and consultations.Results: We highlight that the parent’s acceptance of the pediatric HIV screening is based on three elements.Firstly, the health care workers by his speech (which indicates its own knowledge and perceptions on the infection) directed towards mothers’ influences their acceptance or not of the HIV test. Secondly, the mother who by her knowledge and perceptions on HIV, whose particular status, give an impression of her own wellbeing for her and her child influences any acceptance of the pediatric HIV test. Thirdly, the marital environment of the mother, particularly characterized by the ease of communication within the couple, to speak about the HIV test and its realization for the parents or the mother only are many factors which influence the effective realization of the pediatric HIV testing. The preventive principle of HIV transmission and the desire to realize the test in the newborn are not enough alone to lead to its effective realization, according to certain mothers confronted with the father’s refusal. On the other hand, the other mothers refusing the realization of the pediatric test told to be opposed to it; of course, even if their partner would accept it.Discussion: The mothers are the principal facing the pediatric HIV question and fear the reprimands and stigma. The father, the partner could be an obstacle, when he is opposed to the infant HIV testing, or also the facilitator with his realization if he is convinced. The father position thus remains essential face to the question of pediatric HIV testing acceptability. The mothers are aware of this and predict the difficulties of achieving their infant to be tested without the preliminary opinion of their partner at the same time father, and head of the family.Conclusion: The issue of pediatric HIV testing, at the end of our analysis, highlights three elements which require a comprehensive management to improve the coverage of pediatric HIV test. These three elements would not exist without being influenced; therefore they are constantly in interaction and prevent or support the realization or not pediatric test. Also, with the aim to improve the pediatric HIV test coverage, it is necessary to take into account the harmonious management of these elements. Firstly, the mother alone (with her knowledge, and perceptions), its marital environment (with the proposal of the HIV test integrating (1) the partner and/or father with his perceptions and knowledge on HIV infection and (2) facility of speaking about the test and its realization at both or one about the parents, the mother) and of the knowledge, attitudes and practices about the infection of health care workers of the sanitary institution.Recommendations: Our recommendations proposed taking into account a redefinition of the HIV/AIDS approach towards the families exposed to HIV and a more accentuated integration of the father facilitating their own HIV test acceptation and that of his child.Keywords: acceptability, HIV testing, children, infantsArticle in French
L1CAM expression in uterine carcinosarcoma is limited to the epithelial component and may be involved in epithelial-mesenchymal transition
Uterine carcinosarcoma (UCS) has been proposed as a model for epithelial-mesenchymal transition (EMT), a process characterized by a functional change facilitating migration and metastasis in many types of cancer. L1CAM is an adhesion molecule that has been involved in EMT as a marker for mesenchymal phenotype. We examined expression of L1CAM in UCS in a cohort of 90 cases from four different centers. Slides were immunohistochemically stained for L1CAM and scored in four categories (0%, 50%). A score of more than 10% was considered positive for L1CAM. The median age at presentation was 68.6years, and half of the patients (53.3%) presented with FIGO stage 1 disease. Membranous L1CAM expression was positive in the epithelial component in 65.4% of cases. Remarkably, expression was negative in the mesenchymal component. In cases where both components were intermingled, expression limited to the epithelial component was confirmed by a double stain for L1CAM and keratin. Expression of L1CAM did not relate to overall or disease-free survival. Our findings suggest L1CAM is either not a marker for the mesenchymal phenotype in EMT, or UCS is not a good model for EMT
Teaching child and adolescent psychiatry to undergraduate medical students - A survey in German-speaking countries
Objective
To conduct a survey about teaching child and adolescent psychiatry to undergraduate medical students in German-speaking countries.
Methods
A questionnaire was sent to the 33 academic departments of child and adolescent psychiatry in Germany, Austria, and the German-speaking part of Switzerland.
Results
All departments responded. For teaching knowledge, the methods most commonly reported were lectures and case presentations. The most important skills to be taught were thought to be how to assess psychopathology in children and how to assess families. For elective courses, the departments reported using a wide range of teaching methods, many with active involvement of the students. An average of 34 hours per semester is currently allocated by the departments for teaching child and adolescent psychiatry to medical students. Required courses are often taught in cooperation with adult psychiatry and pediatrics. Achievement of educational objectives is usually assessed with written exams or multiple-choice tests. Only a minority of the departments test the achievement of skills.
Conclusions
Two ways of improving education in child and adolescent psychiatry are the introduction of elective courses for students interested in the field and participation of child and adolescent psychiatrists in required courses and in longitudinal courses so as to reach all students. Cooperation within and across medical schools can enable departments of child and adolescent psychiatry, despite limited resources, to become more visible and this specialty to become more attractive to medical students. Compared to the findings in earlier surveys, this survey indicates a trend towards increased involvement of academic departments of child and adolescent psychiatry in training medical students
Phase diagram of the metal-insulator transition in 2D electronic systems
We investigated the interdependence of the effects of disorder and carrier
correlations on the metal-insulator transition in two-dimensional electronic
systems. We present a quantitative metal-insulator phase diagram. Depending on
the carrier density we find two different types of metal-insulator transition -
a continuous localization for rs=<8 and a discontinuous transition at higher
rs. The critical level of disorder at the transition decreases with decreasing
carrier density. At very low carrier densities we find that the system is
always insulating. The value of the conductivity at the transition is
consistent with recent experimental measurements. The self-consistent method
which we have developed includes the effects of both disorder and correlations
on the transition, using a density relaxation theory with the Coulomb
correlations determined from numerical simulation data.Comment: 4 pages, RevTeX + epsf, 5 figures. New comments on conducting phase
and on the conductivity. References updated and correcte
A Viscoelastic model of phase separation
We show here a general model of phase separation in isotropic condensed
matter, namely, a viscoelastic model. We propose that the bulk mechanical
relaxation modulus that has so far been ignored in previous theories plays an
important role in viscoelastic phase separation in addition to the shear
relaxation modulus. In polymer solutions, for example, attractive interactions
between polymers under a poor-solvent condition likely cause the transient
gellike behavior, which makes both bulk and shear modes active. Although such
attractive interactions between molecules of the same component exist
universally in the two-phase region of a mixture, the stress arising from
attractive interactions is asymmetrically divided between the components only
in dynamically asymmetric mixtures such as polymer solutions and colloidal
suspensions. Thus, the interaction network between the slower components, which
can store the elastic energy against its deformation through bulk and shear
moduli, is formed. It is the bulk relaxation modulus associated with this
interaction network that is primarily responsible for the appearance of the
sponge structure peculiar to viscoelastic phase separation and the phase
inversion. We demonstrate that a viscoelastic model of phase separation
including this new effect is a general model that can describe all types of
isotropic phase separation including solid and fluid models as its special
cases without any exception, if there is no coupling with additional order
parameter. The physical origin of volume shrinking behavior during viscoelastic
phase separation and the universality of the resulting spongelike structure are
also discussed.Comment: 14 pages, RevTex, To appear in Phys. Rev
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