The role of string-like, supramolecular assemblies in reentrant supernematic liquid crystals

Using a combination of isothermal-isobaric Monte Carlo and microcanonical molecular dynamics we investigate the relation between structure and self-diffusion in various phases of a model liquid crystal using the Gay-Berne-Kihara potential. These molecules are confined to a mesoscopic slit-pore with atomically smooth substrate surfaces. As reported recently [see M. G. Mazza {\em et al.}, Phys. Rev. Lett. {\bf 105}, 227802 (2010)], a reentrant nematic (RN) phase may form at sufficiently high pressures/densities. This phase is characterized by a high degree of nematic order and a substantially enhanced self-diffusivity in the direction of the director $\hat{\bm{n}}$ which exceeds that of the lower-density nematic and an intermittent smectic A phase by about an order of magnitude. Here we demonstrate that the unique transport behavior in the RN phase may be linked to a confinement-induced packing effect which causes the formation of supramolecular, string-like conformations. The strings consist of several individual molecules that are capable of travelling in the direction of $\hat{\bm{n}}$ as individual "trains" consisting of chains of molecular "cars". Individual trains run in parallel and may pass each other at sufficiently high pressures.Comment: 24 page

¿A qué tengo miedo?

OBJECTIVE: To determine whether male and female adolescents report currently experiencing fear and to identify their most common causes of fear. METHODS: This was a descriptive, prospective, cross-sectional study of a convenience sample, involving analysis of questionnaires administered to adolescents seen at a public university adolescent clinic between 2004 and 2006. The adolescents self-administered the Youth Self Report (YSR - a screening tool for behavioral problems) while in the waiting room. The responses to item 29, I am afraid of certain animals, situations or places other than school. (Describe) were analyzed. The chi-square test was used to determine whether age group (10-12, 13-15 or 16-19 years) and gender were associated with responses to item 29 of the YSR. RESULTS: 323 adolescents' questionnaires were analyzed, 184 (57%) of whom were female. Fear was more common among the females (p=0.009). There was a significant association between the responses to item 29 and age group. Older adolescents were more likely to check the option often true than younger adolescents (p=0.048). There were a variety of different causes of fear, but animals predominated. CONCLUSIONS: Among these adolescents, fear tended to be associated with the female gender and older age groups. Education, culture and preservation of the species may affect the degree of fear in females. In contrast with reports in the literature, in this study older students reported more fear, perhaps due to greater awareness of the emotion or due to the expectations of the age group analyzed.OBJETIVO: Verificar si adolescentes de ambos sexos refieren el miedo como una emoción presente y cuáles son las causas más comunes de miedo. MÉTODOS: Estudio descriptivo, prospectivo, de corte transversal, con determinación de la muestra por conveniencia, que implicó el análisis de cuestionarios aplicados a los adolescentes atendidos entre 2004 y 2006, en un ambulatorio de Medicina del Adolescente. Los adolescentes contestaron en la sala de espera el Youth Self Report (YSR) - instrumento de selección para problemas de comportamiento. Se analizaron las respuestas en el ítem 29 - «tengo miedo a animales, situaciones o lugares, no incluyendo la escuela. ¿Cuáles?» Se utilizó el test de chi-cuadrado para verificar la asociación entre las franjas de edad (10-12 años, 13-15 años y 16-19 años) y sexo con el ítem 29 del YSR. RESULTADOS: Se evaluaron 323 protocolos, 184 (57,0%) eran del sexo femenino. La emoción miedo fue predominante en el sexo femenino (p=0,009). Hubo una asociación significante entre las respuestas al ítem 29 y la franja de edad, en la que los mayores señalaron más la opción «frecuentemente presente» que los menores (p=0,048). Los motivos de miedo fueron diversos, pero los animales predominaron. CONCLUSIONES: La emoción miedo estuvo más asociada al sexo femenino y a la franja de edad de los individuos mayores. La educación, la cultura y la preservación de la especie pueden estar influenciando la presencia del miedo en las mujeres. Diferentemente de la literatura, los mayores relataron más tener miedo, quizá debido a la mayor consciencia de esta emoción o por las expectativas de la franja de edad.OBJETIVO: Verificar se adolescentes de ambos os sexos referem o medo como uma emoção presente e quais são as causas mais comuns de medo. MÉTODOS: Estudo descritivo, prospectivo, de corte transversal, com determinação da amostra por conveniência, que envolveu a análise de questionários aplicados aos adolescentes atendidos entre 2004 e 2006 em um ambulatório de Medicina do Adolescente. Os adolescentes responderam na sala de espera o Youth Self Report (YSR) - instrumento de triagem para problemas de comportamento. Foram analisadas as respostas ao item 29 - tenho medo de animais, situações ou lugares, sem incluir a escola. Quais? O teste do qui-quadrado foi utilizado para verificar a associação entre as faixas etárias (10-12, 13-15 e 16-19 anos) e sexo com o item 29 do YSR. RESULTADOS: Avaliaram-se 323 protocolos, 184 (57%) eram do sexo feminino. A emoção medo foi predominante no sexo feminino (p=0,009). Houve uma associação significante entre as respostas ao item 29 e a faixa etária, em que os mais velhos assinalaram mais a opção frequentemente presente do que os mais novos (p=0,048). Os motivos de medo foram diversos, mas os animais predominaram. CONCLUSÕES: A emoção medo esteve mais associada ao sexo feminino e a faixa etária dos adolescentes mais velhos. A educação, a cultura e a preservação da espécie podem estar influenciando a presença de medo nas mulheres. Diferentemente da literatura, os mais velhos relataram mais terem medo, talvez devido à maior consciência desta emoção ou pelas expectativas da faixa etária.UNIFESP Departamento de Pediatria Centro de Atendimento e Apoio ao AdolescenteUNIFESP Departamento de Pediatria Setor de Medicina do AdolescenteUNIFESP, Depto. de Pediatria Centro de Atendimento e Apoio ao AdolescenteUNIFESP, Depto. de Pediatria Setor de Medicina do AdolescenteSciEL

Identity development in brazilian adolescents

Identidade é composta pelos valores, crenças e metas com que um indivíduo está comprometido. Existem quatro estados de identidade: difusão, pré-fechamento, moratória e identidade estabelecida, identificados de acordo com a presença de exploração das alternativas e com a intensidade dos compromissos. Este trabalho verificou os estados de identidade em que se encontravam 753 adolescentes de 15 a 18 anos, estudantes do Ensino Médio de escolas públicas de São Paulo que responderam ao EOMEIS 2, uma escala tipo Likert que avalia os estados de identidade. A maioria dos adolescentes encontrava-se em moratória. Verificou-se uma associação positiva entre o sexo feminino e os estados de moratória e identidade estabelecida; entre a primeira série do Ensino Médio e o estado de pré-fechamento.Identity is composed by values, beliefs and goals to which an individual is committed. There are four states of identity determined according to the exploration of alternatives and the intensity of commitment: diffusion, foreclosure, moratorium and achievement. This work evaluated the identity states of 753 Brazilian adolescents from 15 to 18 years old who study in public schools in the city of São Paulo. They responded to the Extended Objective Measure of Ego Identity Status (EOMEIS 2) a kind of Likert scale that measures states of identity. Most adolescents were in moratorium state. A positive association was identified between the female gender and both the states of moratorium and achievement, as well as, between the first year of high school and foreclosure

The Stokes conjecture for waves with vorticity

We study stagnation points of two-dimensional steady gravity free-surface water waves with vorticity. We obtain for example that, in the case where the free surface is an injective curve, the asymptotics at any stagnation point is given either by the “Stokes corner flow” where the free surface has a corner of 120°, or the free surface ends in a horizontal cusp, or the free surface is horizontally flat at the stagnation point. The cusp case is a new feature in the case with vorticity, and it is not possible in the absence of vorticity. In a second main result we exclude horizontally flat singularities in the case that the vorticity is 0 on the free surface. Here the vorticity may have infinitely many sign changes accumulating at the free surface, which makes this case particularly difficult and explains why it has been almost untouched by research so far. Our results are based on calculations in the original variables and do not rely on structural assumptions needed in previous results such as isolated singularities, symmetry and monotonicity

FES-project Detectie Phytophthora met behulp van padlock probes en micro-array

De laatste jaren heeft de ontwikkeling van (moleculaire) detectiemethoden van planten-pathogenen een hoge vlucht genomen en inmiddels vinden deze methoden hun weg naar toepassing in de praktij

Conifold Transitions and Mirror Symmetries

Recent work initiated by Strominger has lead to a consistent physical interpretation of certain types of transitions between different string vacua. These transitions, discovered several years ago, involve singular conifold configurations which connect distinct Calabi-Yau manifolds. In this paper we discuss a number of aspects of conifold transitions pertinent to both worldsheet and spacetime mirror symmetry. It is shown that the mirror transform based on fractional transformations allows an extension of the mirror map to conifold boundary points of the moduli space of weighted Calabi-Yau manifolds. The conifold points encountered in the mirror context are not amenable to an analysis via the original splitting constructions. We describe the first examples of such nonsplitting conifold transitions, which turn out to connect the known web of Calabi-Yau spaces to new regions of the collective moduli space. We then generalize the splitting conifold transition to weighted manifolds and describe a class of connections between the webs of ordinary and weighted projective Calabi-Yau spaces. Combining these two constructions we find evidence for a dual analog of conifold transitions in heterotic N$=$2 compactifications on K3$\times$T$^2$ and in particular describe the first conifold transition of a Calabi-Yau manifold whose heterotic dual has been identified by Kachru and Vafa. We furthermore present a special type of conifold transition which, when applied to certain classes of Calabi-Yau K3 fibrations, preserves the fiber structure.Comment: 23 page

Inflation, Large Branes, and the Shape of Space

Linde has recently argued that compact flat or negatively curved spatial sections should, in many circumstances, be considered typical in Inflationary cosmologies. We suggest that the "large brane instability" of Seiberg and Witten eliminates the negative candidates in the context of string theory. That leaves the flat, compact, three-dimensional manifolds -- Conway's *platycosms*. We show that deep theorems of Schoen, Yau, Gromov and Lawson imply that, even in this case, Seiberg-Witten instability can be avoided only with difficulty. Using a specific cosmological model of the Maldacena-Maoz type, we explain how to do this, and we also show how the list of platycosmic candidates can be reduced to three. This leads to an extension of the basic idea: the conformal compactification of the entire Euclidean spacetime also has the topology of a flat, compact, four-dimensional space.Comment: 29 pages, clarifications, typos fixed, references adde

Diagnostic application of padlock probes—multiplex detection of plant pathogens using universal microarrays

Padlock probes (PLPs) are long oligonucleotides, whose ends are complementary to adjacent target sequences. Upon hybridization to the target, the two ends are brought into contact, allowing PLP circularization by ligation. PLPs provide extremely specific target recognition, which is followed by universal amplification and microarray detection. Since target recognition is separated from downstream processing, PLPs enable the development of flexible and extendable diagnostic systems, targeting diverse organisms. To adapt padlock technology for diagnostic purposes, we optimized PLP design to ensure high specificity and eliminating ligation on non-target sequences under real-world assay conditions. We designed and tested 11 PLPs to target various plant pathogens at the genus, species and subspecies levels, and developed a prototype PLP-based plant health chip. Excellent specificity was demonstrated toward the target organisms. Assay background was determined for each hybridization using a no-target reference sample, which provided reliable and sensitive identification of positive samples. A sensitivity of 5 pg genomic DNA and a dynamic range of detection of 100 were observed. The developed multiplex diagnostic system was validated using genomic DNAs of characterized isolates and artificial mixtures thereof. The demonstrated system is adaptable to a wide variety of applications ranging from pest management to environmental microbiology

Identity status of adolescents living in institutional shelters

Introduction: The development of adolescents living outside the environment of their families and residing in institutional shelters presents peculiar characteristics in the interactions established in their daily lives and the constitution of their identities. Erikson’s psychosocial theory studies identity formation, observing exploration and commitment. Identity status can be classified as identity diffusion, foreclosure, moratorium, and identity achievement.Objective: To evaluate identity status of adolescents living in institutional shelters.Methods: Eighty-seven adolescents living in institutional shelters (age 12–17) individually responded to the Extended Objective Measure of the Ego Identity Status II (EOMEIS II). The data were analysed using descriptive and inferential statistics which included the following variables: gender, age range, schooling, and time of sheltering.Results: There was a prevalence of the identity diffusion status in both genders, regardless of the length of schooling and despite the time of sheltering. There were differences in the results considering age range (p = 0,033).Conclusion: Older adolescents showed greater losses in identity development, with more negative and immature states of identity, indicative of poor preparation for leaving the institution (at age 18)

Focusing on Quality Patient Care in the New Global Subsidy for Malaria Medicines

Tido von Schoen-Angerer and colleagues discuss the new Affordable Medicines Facility for malaria (AMFm), which subsidizes and facilitates access to artemisinin-based combination therapy, and what mechanisms are needed to ensure it stays focused on quality patient care