Nitrogen fixation and transfer in open ocean diatom–cyanobacterial symbioses

Many diatoms that inhabit low-nutrient waters of the open ocean live in close association with cyanobacteria. Some of these associations are believed to be mutualistic, where N2-fixing cyanobacterial symbionts provide N for the diatoms. Rates of N2 fixation by symbiotic cyanobacteria and the N transfer to their diatom partners were measured using a high-resolution nanometer scale secondary ion mass spectrometry approach in natural populations. Cell-specific rates of N2 fixation (1.15–71.5 fmol N per cell h−1) were similar amongst the symbioses and rapid transfer (within 30 min) of fixed N was also measured. Similar growth rates for the diatoms and their symbionts were determined and the symbiotic growth rates were higher than those estimated for free-living cells. The N2 fixation rates estimated for Richelia and Calothrix symbionts were 171–420 times higher when the cells were symbiotic compared with the rates estimated for the cells living freely. When combined, the latter two results suggest that the diatom partners influence the growth and metabolism of their cyanobacterial symbionts. We estimated that Richelia fix 81–744% more N than needed for their own growth and up to 97.3% of the fixed N is transferred to the diatom partners. This study provides new information on the mechanisms controlling N input into the open ocean by symbiotic microorganisms, which are widespread and important for oceanic primary production. Further, this is the first demonstration of N transfer from an N2 fixer to a unicellular partner. These symbioses are important models for molecular regulation and nutrient exchange in symbiotic systems

Polymorphism of chiral thioester studied by dielectric spectroscopy

(S)-(+)-4'-[(4-(1-methylheptyloxycarbonylphenyl) thiocarbonylphenyl]-decyloxybenzoate (in short 10.OPOSMH) was studied by complementary methods. The substance shows rich polymorphism. In addition to ferroelectric and antiferroelectric smectic C^{*} phases it possesses three ferrielectric sub-phases. Phase transitions between the phases were revealed by differential scanning calorimetry and static dielectric permittivity measurements. The aim of this paper was to study phase transitions and differences in dielectric spectra shown by different phases. Collective and molecular dynamics of all phases shown by 10.OPOSMH will be discussed in terms of theoretical models. Dielectric spectra of antiferroelectric phase show two characteristic dielectric relaxation modes: one connected with the molecular process (reorientation around the short axis) and the other originating from fluctuations of antiferroelectric order parameters

O papel do psicólogo e das entidades junto a crianças e adolescentes em situação de risco

Neste artigo, serão apresentados dados de uma pesquisa que objetivou identificar o tipo de trabalho desenvolvido por entidades e psicólogos responsáveis pelo atendimento de crianças e adolescentes em situação de risco. Foram realizadas 21 entrevistas semi-estruturadas com representantes e psicólogos dessas entidades. Na análise dos dados, utilizou-se a técnica de análise de conteúdo temático, de Bardin. As instituições investigadas atendem, em sua maioria, sujeitos de classe baixa, de 7 a 18 anos. Entre os tipos de trabalho desenvolvidos, estão atendimento jurídico, psicoterápico, médico-hospitalar e informativoeducacional. Os resultados demonstraram que há superposição de papéis entre organizações governamentais (OGs), conselhos Tutelares e de Direitos e organizações não-governamentais (ONGs). Quanto ao trabalho desenvolvido pelos psicólogos nas instituições, sobressaiu a concepção fundamentada no modelo clínico e individual. Falta às instituições e aos psicólogos maior conhecimento do papel desse profissional junto às políticas públicas direcionadas a crianças e adolescentes em situação de risco

A cultura profissional do psicólogo e o ideário individualista: implicações para a prática no campo da assistência pública à saúde Psychologist's professional culture and individualistic values: consequences in the practices in public health services

Objetiva-se refletir acerca de alguns elementos que definem a cultura profissional do psicólogo no Brasil, bem como nos seus efeitos sobre as práticas realizadas nas instituições públicas de saúde. O "sujeito psicológico", modelo de subjetividade pregnante entre os psicólogos, é um desses elementos definidores da sua cultura profissional, representação desenvolvida a partir do ideário individualista e da difusão dos saberes "psi" na nossa sociedade. A hegemonia dessa concepção de subjetividade tem conseqüências importantes para as práticas realizadas nas instituições públicas de saúde, entre as quais destacam-se: conflito entre as representações de saúde/doença entre usuários e profissionais; baixa eficácia das terapêuticas e alto índice de abandono dos tratamentos; seleção e hierarquização da clientela. Por outro lado, configura-se enquanto obstáculo à criação de uma "cultura avaliadora" entre os profissionais e à construção de instrumentos que permitam ao psicólogo avaliar continuamente o funcionamento dos serviços e práticas nas instituições públicas de saúde.<br>The aim of this paper is to reflect about some elements that are defining the professional culture of the psychologist in Brazil, as well as its effects upon the institutional practices in the public health service. The "psychological subject", model of subjectivity among psychologist is one of the defining elements of this professional culture, representation developed from the individualistic values and psi knowledge in our society. The hegemony of this conception of subjectivity has important consequences in the practices accomplished in the public health institutions, such as conflicts in the representations of health and illness between users and professionals; little efficiency in the therapeutic services and high index of desertion of treatment; hierarchies and discrimination among service users. On the other hand, there always appear obstacles to the creation of an "evaluation culture" among professionals and the construction of instruments that could allow the psychologist to continuously evaluate the quality of their services and practices in the public health institution

Concurrent outbreaks of cholera and peripheral neuropathy associated with high mortality among persons internally displaced by a volcanic eruption

In October 2004, Manam Island volcano in Papua New Guinea erupted, causing over 10 000 villagers to flee to internally displaced person (IDP) camps, including 550 from Dugulaba village. Following violence over land access in March 2010, the IDPs fled the camps, and four months later concurrent outbreaks of acute watery diarrhea and unusual neurological complaints were reported in this population. A retrospective case-control study was conducted to identify the risk factors for peripheral neuropathy. Rectal swabs were collected from cases of acute watery diarrhea. Hair and serum metals and metalloids were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). There were 17 deaths among the 550 village inhabitants during the outbreak period at a crude mortality rate 21-fold that of a humanitarian crisis. Vibrio cholerae O1 El Tor Ogawa was confirmed among the population. Access to community-level rehydration was crucial to mortality. Peripheral neuropathy was diagnosed among cases with neurological symptoms. A balanced diet was significantly protective against neuropathy. A dose-response relationship was seen between peripheral neuropathy and a decreasing number of micronutrient- rich foods in the diet. Deficiencies in copper, iron, selenium and zinc were identified among the cases of peripheral neuropathy. Cholera likely caused the mostly preventable excess mortality. Peripheral neuropathy was not caused by cholera, but cholera may worsen existing nutritional deficiencies. The peripheral neuropathy was likely caused by complex micronutrient deficiencies linked to non-diversified diets that potentially increased the vulnerability of this population, however a new zinc-associated neuropathy could not be ruled out. Reoccurrence can be prevented by addressing the root cause of displacement and ensuring access to arable land and timely resettlement

Sexualidade e reprodução: usos e valores relativos ao desejo de filhos entre casais de camadas médias no Rio de Janeiro, Brasil Sexuality and reproduction: uses and values related to the desire for children among middle-class couples in Rio de Janeiro, Brazil

Este trabalho analisa aspectos constitutivos da dinâmica sexual conjugal moderna entre casais de orientação heterossexual como parte dos resultados de uma pesquisa etnográfica realizada com "casais inférteis" no Rio de Janeiro, Brasil (2004-2005). O grupo investigado pode ser culturalmente definido por sua imersão na configuração de valores individualistas. Analisamos certos aspectos referidos pelos casais a partir dos investimentos em recursos médicos conceptivos. Destacam-se as idéias de "privacidade" e "espontaneidade" como expressões obrigatórias do exercício da sexualidade e da reprodução. Partiu-se do pressuposto de que tanto a experiência reprodutiva quanto a sexual enfatizam a primazia da representação de uma suposta liberdade de escolha. Como estratégia metodológica, privilegiou-se a trajetória de vida dos casais utilizando entrevistas semi-estruturadas e observação no contexto das entrevistas. Os resultados apontam formas divergentes, ou mesmo contraditórias, de vivenciar a experiência da parentalidade: de um lado, o filho como resultado "natural" da relação conjugal e, de outro, como fruto de uma escolha racional.<br>This study analyzes aspects comprising the modern conjugal dynamics of heterosexual couples as part of the results of an ethnographic study of "infertile couples" in Rio de Janeiro, Brazil (2004-2005). The target group can be defined culturally by its immersion in the configuration of individualist values. We analyze certain aspects reported by the couples based on their investments in medical resources for conception. The notions of "privacy" and "spontaneity" stood out as obligatory expressions in the exercise of sexuality and reproduction. The premise was that reproductive and sexual experience emphasizes the primacy of the representation of a supposed freedom of choice. The central methodological strategy was the couple's life trajectory, using semi-structured interviews and observation within the context of the interviews. The findings show divergent or even contradictory forms of experiencing parenthood: on the one hand, the child as the "natural" result of the conjugal relationship, and on the other, as the result of a rational choice