Boyle's law and gravitational instability

We have re-examined the classical problem of the macroscopic equation of state for a hydrostatic isothermal self-gravitating gas cloud bounded by an external medium at constant pressure. We have obtained analytical conditions for its equilibrium and stability without imposing any specific shape and symmetry to the cloud density distribution. The equilibrium condition can be stated in the form of an upper limit to the cloud mass; this is found to be inversely proportional to the power 3/2 of a form factor \mu characterizing the shape of the cloud. In this respect, the spherical solution, associated with the maximum value of the form factor, \mu = 1, turns out to correspond to the shape that is most difficult to realize. Surprisingly, the condition that defines the onset of the Bonnor instability (or gravothermal catastrophe) can be cast in the form of an upper limit to the density contrast within the cloud that is independent of the cloud shape. We have then carried out a similar analysis in the two-dimensional case of infinite cylinders, without assuming axisymmetry. The results obtained in this paper generalize well-known results available for spherical or axisymmetric cylindrical isothermal clouds that have had wide astrophysical applications, especially in the study of the interstellar medium.Comment: 9 pages, 2 figures, to appear in A&

Collaborative Writing with Young Multilingual Learners

Effectively teaching writing to multilingual learners (MLs) has been identified as one of the most prominent challenges currently facing educators. Collaborative writing has been identified as one promising pedagogical practice that responds to this challenge; however, little of the existing research focuses on the elementary level. This study seeks to address this gap in the literature, describing a design-based research study focused on collaborative writing with MLs in a diverse first-grade classroom. This paper showcases two iterations of collaborative writing, closely examining the how-to and opinion texts that two focal MLs produced with their peers. The evaluation of students’ writing revealed that their collaboratively produced texts varied across the writing activities. In some instances, the students’ texts exhibited their clear understanding of the genre, including its purpose and stages, as well as their ability to control and implement different language features. In other cases, their texts indicated that they needed further instruction or revision in specific areas. This paper concludes with implications for future research as it relates to collaborative writing with young MLs, underscoring the need for additional work in this area and the promise of this approach to writing instruction

Health Professional Well-being and Preparedness During the Covid-19 Pandemic in Trinidad and Tobago: an Online Survey

Introduction: Poor well-being impacts mental health and subsequently affects personal lives, leads to absenteeism, poor productivity, and compromised patient safety. Frontline healthcare workers are highly vulnerable to COVID-19 pandemic-related mental health strain. This study assessed the well-being and preparedness of frontline healthcare workers in Trinidad and Tobago during the pandemic. Methods: An online cross-sectional survey was sent to doctors, nurses, and prehospital providers from public and private healthcare sectors. Data was collected from May to June 2020 utilizing a self- administered online platform. The WHO Five Well-being Index (WHO-5) was used to assess well-being. Raw scores less than 13 indicated that participants were at risk for depression. Descriptive statistics and content analysis were used to analyze data. Results: There were 296 respondents comprising 55.4% (n=164) doctors, 30.1% (n=90) nurses and 14.5% (n=43) prehospital care providers. More than half of participants (55.4%, n=158) scored less than 13 on the WHO-5 indicating that these participants were at risk for developing depression. Approximately 80% of participants did not feel supported by their workplaces. Resident doctors had lower well-being levels (59.4% (n=60), i.e., well-being scores less than 13) compared to attending physicians (45.6% (n=26)), but this was not statistically significant (p = 0.516). Two main categories were identified in the content analysis: factors related to the working environment and coping with COVID-19. Conclusion: Levels of well-being indicated that more than half of the participants were at risk for developing depression. The findings also suggested that workplaces should provide health workers with the basic protective resources required to perform their roles. It is imperative that health organizations increase awareness of well-being and mental health in workplaces and develop interventions to support healthcare workers

Pilot Validation of the Tuberous Sclerosis-Associated Neuropsychiatric Disorders (TAND) Checklist

AbstractBackgroundTuberous sclerosis complex is a multisystem disorder that includes a range of tuberous sclerosis–associated neuropsychiatric disorders (TAND). The lifetime prevalence rates of TAND are very high; yet surveys suggest that the majority of individuals with tuberous sclerosis never receive appropriate assessment or treatment for TAND. To aid systematic enquiry, a TAND Checklist was developed. Here, we performed pilot validation of the TAND Checklist.MethodMixed methods were used across two stages. In stage 1, we gathered feedback on the Checklist from tuberous sclerosis “expert professionals” and “expert parents and caregivers.” The aim was to examine face and content validity. Stage 2 involved the administration of the refined TAND Checklist to 20 parents of individuals with tuberous sclerosis concurrently with four widely used validated rating scales, to examine external validity and obtain qualitative feedback on face-to-face administration of the TAND Checklist.ResultsTwenty professionals and 62 parents and caregivers from 28 countries participated in the pilot. The TAND Checklist demonstrated good face and content validity with high overall mean and median scores. Qualitative analysis highlighted concerns about the likely use of the TAND Checklist, suggesting that family members and individuals with tuberous sclerosis should drive usage. Stage 2 results showed moderate-to-very good external validity across TAND domain and key subdomains. Internal consistency of domains and subdomains was acceptable to very good. Ninety-three percent of all participants (93%) reported four or more lifetime TAND behavioral difficulties.ConclusionThe pilot validation suggested that the TAND Checklist could provide a useful screening tool in clinical settings

Reciprocal knock-in mice to investigate the functional redundancy of lamin B1 and lamin B2.

Lamins B1 and B2 (B-type lamins) have very similar sequences and are expressed ubiquitously. In addition, both Lmnb1- and Lmnb2-deficient mice die soon after birth with neuronal layering abnormalities in the cerebral cortex, a consequence of defective neuronal migration. The similarities in amino acid sequences, expression patterns, and knockout phenotypes raise the question of whether the two proteins have redundant functions. To investigate this topic, we generated "reciprocal knock-in mice"-mice that make lamin B2 from the Lmnb1 locus (Lmnb1(B2/B2)) and mice that make lamin B1 from the Lmnb2 locus (Lmnb2(B1/B1)). Lmnb1(B2/B2) mice produced increased amounts of lamin B2 but no lamin B1; they died soon after birth with neuronal layering abnormalities in the cerebral cortex. However, the defects in Lmnb1(B2/B2) mice were less severe than those in Lmnb1-knockout mice, indicating that increased amounts of lamin B2 partially ameliorate the abnormalities associated with lamin B1 deficiency. Similarly, increased amounts of lamin B1 in Lmnb2(B1/B1) mice did not prevent the neurodevelopmental defects elicited by lamin B2 deficiency. We conclude that lamins B1 and B2 have unique roles in the developing brain and that increased production of one B-type lamin does not fully complement loss of the other

A simbologia do mar nas crônicas Au fond de la mer de Marguerite Duras e Rituel de Clarice Lispector

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Instituto de Letras, Departamento de Línguas Estrangeiras e Tradução, Língua Francesa e respectivas Literaturas, 2017.Este trabalho tem como objetivo fazer um estudo comparado entre as crônicas Au fond de la mer de Marguerite Duras e Rituel de Clarice Lispector. Tal comparação se baseia pela análise da simbologia do mar que busca relacionar o mar e os acontecimentos da vida das duas escritoras. Tal estudo ampara-se na significação do símbolo mar do Dicionário de Símbolos de Jean Chevalier e Alain Gheerbrant. A análise visa revelar, que mesmo vindo de duas autoras distintas, o mar pode ter a mesma significação dentro das crônicas escolhidas.Ce travail a comme but faire l’étude comparée entre les chroniques Au fond de la mer de Marguerite Duras et Rituel de Clarice Lispector. Cette comparaison est basée sur l’analyse de la symbologie de la mer que cherche relationner la mer et les événements de la vie de ces écrivains. Cette étude se soutient par la signification du symbole de la mer du Dictionnaire de Symboles de Jean Chevalier et Alain Gheerbrant. L’analyse vise montrer, que même avec des auteurs différents, la mer peut avoir la même signification dans les chroniques sélectionnés

Ribosomal DNA and the Phylogeny of Frogs

Phylogenetic analysis of 1656 aligned sites in the 28S ribosomal RNA gene of frogs supports some of the recently recognized higher groups of anurans but provides counter-support for others. The 28S rDNA data support the monophyly of the recently recognized Pipanura (me- sobatrachians plus neobatrachians), which in turn indicates paraphyly of archaeobatrachians. Me- sobatrachians (pelobatoids plus pipoids), which are either considered paraphyletic or weakly sup- ported as monophyletic in morphological analyses, also receive support as a monophyletic group from the 28S rDNA data. Hyloidea (=Bufonoidea), which is widely recognized but lacks morphological support, receives some molecular support as being monophyletic. However, Ranoidea, which is supported by morphology, is counter-supported by ribosomal DNA. In particular, den- drobatids do not group with ranids (but sometimes group with hyloids). A combined analysis of the molecular data with the morphological data of Duellman and Trueb (1986:Biology of Am- phibians) supports Pipanura, Mesobatrachia, Neobatrachia, and Hyloidea, but shows the ranoids as paraphyletic (with Dendrobatidae related to Hyloidea). The agreement between molecular and morphological data in several regions of the anuran tree indicates an approaching stabilization of traditionally labile higher frog classification