Intermolecular forces and fixed-node diffusion Monte Carlo: A brute force test of accuracies for He-2 and He-LiH

The accuracy of the fixed-node approximation and diffusion Monte Carlo method in computing the interaction energy of van der Waals systems was investigated. Tests were carried out by simulating the electronic structures of He-2 and He-LiH. These two systems were chosen as representative of two fundamentally different interactions, namely the weak dispersion forces in He-2 and the dipole/induced-dipole interaction in He-LiH. The results for both systems are in excellent agreement with "state of the art" calculations, thereby indicating a high accuracy for the fixed-node approximation. Also, our interaction energies for He-LiH indicate that the coupled cluster single double triple method [Taylor and Hinde, J. Chem. Phys. 111, 973 (1999)] gives an accurate prediction of the interaction potential for that system. (C) 2003 American Institute of Physics

Синтез ультрадисперсного кристаллического карбида кремния в гиперскоростной струе углерод-кремниевой электроразрядной плазмы

Наночастицы карбида кремния (SiC) могут использоваться для армирования материалов, создания наноструктурированной керамики, микроэлектромеханических систем. В работе представлены результаты плазмодинамического синтеза ультрадисперсных порошков карбида кремния. Этот метод был реализован путем синтеза в электроразрядной плазменной струе, создаваемой сильноточным импульсным коаксиальным магнитоплазменным ускорителем. Синтезированные продукты были проанализированы несколькими современными методами. Согласно результатам анализа, все продукты в основном состоят из кубического карбида кремния (b-SiC) с небольшим количеством непрореагировавших прекурсоров. Сравнение результатов экспериментов позволило сделать выводы о путях контроля фазового состава и дисперсности продукта.Silicon carbide (SiC) nanoparticles can be used for ceramics reinforcement, creation of nanostructured ceramics, microelectromechanical systems. The work presents the results of plasmadynamic synthesis of silicon carbide ultradipersed powders. This method was realized by the synthesis in an electrodischarge plasma jet generated by a high-current pulsed coaxial magnetoplasma accelerator. The synthesized products were analysed by several modern techniques. According to analysis results all the products mainly composed of cubic silicon carbide (b-SiC) with a small amount of unreacted precursors. Comparison of the results of experiments made it possible to draw conclusions on ways to control product phase composition and dispersion

“I drive outside of peak time to avoid traffic jams—Public transport is not attractive here.” Challenging discourses on travel to the University campus in Manila

One of the major narratives in transport policy internationally concerns the promotion of private versus public modes. The Global North has many examples where public transport, walking and cycling networks are well developed, yet examples from the Global South are less evident. There is a historical failure of replicating policies and practices from the Global North, particularly in perpetuating the highway building model, often unsuitable to the cultural contexts in the Global South. This paper examines individual attitudes and discourses concerning travel to De La Salle University campus, in Metro Manila, the Philippines. 42 participants are surveyed using Q methodology. Four discourses are developed, reflecting attitudes to growing automobility in Manila, public transport service provision, the difficulties of travelling in the city and the aspiration for increased comfort whilst travelling. Manila provides an example of the complexities in moving towards greater sustainable travel in the southeast Asian context where levels of private car usage are already high. It is hoped that a greater awareness of the problems of the current travel experiences might lead to us to seek different narratives, where transport systems can be developed which better serve social equity and environmental goals

An Age-Associated Decline in Thymic Output Differs in Dog Breeds According to Their Longevity

The age associated decline in immune function is preceded in mammals by a reduction in thymic output. Furthermore, there is increasing evidence of a link between immune competence and lifespan. One approach to determining thymic output is to quantify signal joint T cell receptor excision circles (sj-TRECs), a method which has been developed and used in several mammalian species. Life expectancy and the rate of aging vary in dogs depending upon their breed. In this study, we quantified sj-TRECs in blood samples from dogs of selected breeds to determine whether there was a relationship between longevity and thymic output. In Labrador retrievers, a breed with a median expected lifespan of 11 years, there was an age-associated decline in sj-TREC values, with the greatest decline occurring before 5 years of age, but with sj-TREC still detectable in some geriatric animals, over 13 years of age. In large short-lived breeds (Burnese mountain dogs, Great Danes and Dogue de Bordeaux), the decline in sj-TREC values began earlier in life, compared with small long-lived breeds (Jack Russell terriers and Yorkshire terriers), and the presence of animals with undetectable sj-TRECs occurred at a younger age in the short-lived breeds. The study findings suggest that age-associated changes in canine sj-TRECs are related to breed differences in longevity, and this research highlights the use of dogs as a potential model of immunosenescence

Strategic vision for sustainable urban transport and mobility in Sierra Leone: Practical implementation constraints and opportunities

This document summarises the consensus that emerged during the T-SUM workshop ‘Future Freetown, Improving Mobility – from Vision to Implementation’ that took place on March 4th 2020 in Freetown, Sierra Leone. The participatory workshop was led by SLURC and UCL, with the support of Freetown City Council, the Ministry of Transport and Aviation, the Sierra Leone Road Safety Authority, the Sierra Leone Roads Authority, the Sierra Leone Road Transport Cooperation, the Sierra Leone Institution of Engineer, Fourah Bay College and the Directorate of Science Technology and Innovation. Circa 50 key stakeholders across sectors and representatives of the public participated

Explicitly correlated trial wave functions in Quantum Monte Carlo calculations of excited states of Be and Be-

We present a new form of explicitly correlated wave function whose parameters are mainly linear, to circumvent the problem of the optimization of a large number of non-linear parameters usually encountered with basis sets of explicitly correlated wave functions. With this trial wave function we succeeded in minimizing the energy instead of the variance of the local energy, as is more common in quantum Monte Carlo methods. We applied this wave function to the calculation of the energies of Be 3P (1s22p2) and Be- 4So (1s22p3) by variational and diffusion Monte Carlo methods. The results compare favorably with those obtained by different types of explicitly correlated trial wave functions already described in the literature. The energies obtained are improved with respect to the best variational ones found in literature, and within one standard deviation from the estimated non-relativistic limitsComment: 19 pages, no figures, submitted to J. Phys.

Renal function and volume of infants born with a very low birth-weight: a preliminary cross-sectional study.

AIM: The aim of our study was to compare the function and volumes of kidneys of very low birth-weight (VLBW) and of extremely low birth-weight (ELBW) infants at pre-school ages.PATIENTS AND METHODS: We did a revision of the neonatal records of infants born in our hospital that weighed < or =1500 g at birth. The children were divided into two groups according to their weight at birth: ELBW (<1000 g) and VLBW (1000-1500 g). At the age of 5.7 +/- 1.4 years, the children underwent clinical, laboratory and ultrasound renal assessments.RESULTS: Sixty-nine children fulfilled the requirements for the study. The rate of neonatal treatment with aminoglycosides was higher in ELBW preterms. Renal function parameters, i.e. estimated glomerular filtration rate and albuminuria, did not differ between the two groups of children. Urinary alpha1-microglobulin excretion was significantly higher and kidneys were significantly smaller in the ELBW group than in the VLBW group.CONCLUSION: No impairment or differences in renal parameters were found in pre-school children born ELBW compared with those born with VLBW, except for differences in kidney volume, renal cortical thickness and urinary alpha1-microglobulin excretion. Thus, patients born with ELBW would require a longer follow-up period

Insight in psychosis: a conceptual analysis

INTRODUCTION: In the context of clinical psychiatry, insight is defined as a subcategory of self-awareness of patients, which is related to the recognition of the pathological manifestations that affect them and also the appreciation of the changes that these manifestations cause in their interaction with the outside world. OBJECTIVE: To examine the forms of presentation of insight in schizophrenia and other psychoses. METHODS: Conceptual analysis, with illustrative clinical vignettes, of the relation between insight and several symptomatologic dimensions of schizophrenia and related conditions, regarding clinical, neurocognitive, psychodynamic and transcultural aspects. RESULTS: From a conceptual point of view, the construct is shaped by the theoretical approach adopted; from a clinical point of view, its presentation in psychoses is the result of the interaction with different symptomatologic areas and subjective and cultural aspects of the patient. CONCLUSION: Psychopathology assessment of insight must consider the complexity of the phenomenon, the theoretical approach used, and the clinical purpose for which it is done.INTRODUÇÃO: No contexto da psiquiatria clínica, insight ou crítica da doença é definida como uma subcategoria do autoconhecimento dos pacientes relativa ao reconhecimento das manifestações patológicas que os afetam e também à apreciação das mudanças que tais manifestações causam na sua interação com o mundo. OBJETIVO: Examinar as formas de apresentação do insight na esquizofrenia e em outras psicoses. MÉTODOS: Análise conceitual, com vinhetas clínicas ilustrativas, da relação entre insight e as diversas dimensões sintomatológicas da esquizofrenia e condições relacionadas, considerando aspectos clínicos, neurocognitivos, psicodinâmicos e transculturais. RESULTADOS: Do ponto de vista conceitual, o construto é conformado pela perspectiva teórica adotada; do ponto de vista clínico, sua apresentação nas psicoses é a resultante da interação com os diferentes domínios sintomatológicos e aspectos subjetivos e culturais do paciente. CONCLUSÃO: A avaliação psicopatológica do insight deve levar em conta a complexidade do fenômeno, o recorte teórico em que está situada e a finalidade clínica com que é realizada.13514