193 research outputs found
Electrophysiological characterization of the hyperdirect pathway and its functional relevance for subthalamic deep brain stimulation
The subthalamic nucleus (STN) receives input from various cortical areas via hyperdirect pathway (HDP) which bypasses the basal-ganglia loop. Recently, the HDP has gained increasing interest, because of its relevance for STN deep brain stimulation (DBS). To understand the HDP's role cortical responses evoked by STN-DBS have been investigated. These responses have short (<2 ms), medium (2–15 ms), and long (20–70 ms) latencies. Medium-latency responses are supposed to represent antidromic cortical activations via HDP. Together with long-latency responses the medium responses can potentially be used as biomarker of DBS efficacy as well as side effects. We here propose that the activation sequence of the cortical evoked responses can be conceptualized as high frequency oscillations (HFO) for signal analysis. HFO might therefore serve as marker for antidromic activation. Using existing knowledge on HFO recordings, this approach allows data analyses and physiological modeling to advance the pathophysiological understanding of cortical DBS-evoked high-frequency activity
Competitiveness and communication for effective inoculation byRhizobium, Bradyrhizobium and vesicular-arbuscular mycorrhiza fungi
After a short summary on the ecology and rhizosphere biology of symbiotic bacteria and vesicular-arbuscular (VA) mycorrhiza fungi and their application as microbial inocula, results on competitiveness and communication are summarized. Stress factors such as high temperature, low soil pH, aluminium concentrations and phytoalexins produced by the host plants were studied withRhizobium leguminosarum bv.phaseoli andRhizobium tropici onPhaseolus beans. Quantitative data for competitiveness were obtained by usinggus + (glucoronidase) labelled strains, which produce blue-coloured nodules. ForPhaseolus-nodulating rhizobia, a group specific DNA probe was also developed, which did not hybridize with more than 20 other common soil and rhizosphere bacteria. Results from several laboratories contributing to knowledge of signal exchange and communication in theRhizobium/Bradyrhizobium legume system are summarized in a new scheme, including also defense reactions at the early stages of legume nodule initiation. Stimulating effects of flavonoids on germination and growth of VA mycorrhiza fungi were also found. A constitutive antifungal compound in pea roots, -isoxazolinonyl-alanine, was characterized
Gravitational ultrarelativistic spin-orbit interaction and the weak equivalence principle
It is shown that the gravitational ultrarelativistic spin-orbit interaction
violates the weak equivalence principle in the traditional sense. This fact is
a direct consequence of the Mathisson-Papapetrou equations in the frame of
reference comoving with a spinning test particle. The widely held assumption
that the deviation of a spinning test body from a geodesic trajectory is caused
by tidal forces is not correctComment: 12 page
Widespread spring phenology effects on drought recovery of Northern Hemisphere ecosystems
The time required for an ecosystem to recover from severe drought is a key component of ecological resilience. The phenology effects on drought recovery are, however, poorly understood. These effects centre on how phenology variations impact biophysical feedbacks, vegetation growth and, ultimately, recovery itself. Using multiple remotely sensed datasets, we found that more than half of ecosystems in mid- and high-latitudinal Northern Hemisphere failed to recover from extreme droughts within a single growing season. Earlier spring phenology in the drought year slowed drought recovery when extreme droughts occurred in mid-growing season. Delayed spring phenology in the subsequent year slowed drought recovery for all vegetation types (with importance of spring phenology ranging from 46% to 58%). The phenology effects on drought recovery were comparable to or larger than other well-known postdrought climatic factors. These results strongly suggest that the interactions between vegetation phenology and drought must be incorporated into Earth system models to accurately quantify ecosystem resilience.X.W. was financially supported by the National Natural Science Foundation of China (grant nos. 41922001 and 42171050), the Second Tibetan Plateau Scientific Expedition and Research Program (grant no. 2019QZKK0306) and the National Key Research and Development Program of China (grant no. 2022YFF0801800). S.A.K. was supported by the US Department of Energy Environmental System Science program grant no. DE-SC0022052. A.G. is supported by the Ramon y Cajal Program of the Spanish MICINN under grant RyC2020- 030647-I, and by CSIC under grant PIE-20223AT003. W.K.S. and W.Z. were supported by the NASA Carbon Cycle and Ecosystems Program under grant 80NSSC21K1709.Peer reviewe
Enantioselective Catalytic Desymmetrization of Maleimides by Temporary Removal of an Internal Mirror Plane and Stereoablative Over-reduction: Synthesis of (R)-Pyrrolam A
A highly enantioselective (>95% ee) strategy to affect
the desymmetrization of a maleimide has been performed by
temporary attachment to an anthracene template followed by
asymmetric reduction with an oxazaborolidine catalyst. A stereoablative
over-reduction process was partially responsible for the high
levels of enantioselectivity. Exemplification of the strategy by
stereoselective functionalization and retro-Diels−Alder reaction
provided the natural product pyrrolam A
RELATO DE VISITA TÉCNICA AO ASSENTAMENTO JOSÉ MARIA – PROBLEMATIZANDO A EDUCAÇÃO NO/DO CAMPO
O relato de Experiência a ser compartilhado com os participantes do II MEPEC será organizado no formato de “sessões de apresentação” com apoio de audiovisual. Os autores exporão aos visitantes a vivência ocorrida em setembro de 2016 durante visita técnica ao Campus Avançado do IFC em Abelardo Luz, situado no AssentamentoJosé Maria.Esta visita teve como objetivos:-Compreender o que representa a expressão “sem terra”, de modo a extrapolar a ideia de mera luta pela terra e entender que “sem terra” é uma identidade historicamente construída como afirmação de uma condição social (CALDART, 2001);-Conhecer o movimento pedagógico de uma escola que atua para a formação de sujeitos sociais e de seres humanos que têm a identidade de luta como elemento que os aproxima, a Escola de Ensino Médio Paulo Freire;-Olhar para o Movimento Sem Terra e sua trajetória, em especial, no que diz respeito à Pedagogia e à educação das crianças, jovens e adultos pertencentes ao Movimento, e pensar que em tempos de desumanidade crescente há que investir em processos de formação humana marcados pela alteridade, pelo reconhecimento do outro enquanto um outro diferente de mim;-Compreender a influência e a importância dos movimentos sociais na formação da consciência social do direito a Educação Básica, desde a Educação Infantil;-o direito à escola pública.-Aproximar as/os acadêmicas/os da realidade dos movimentos sociais, de modo que esta relação teoria-prática faça emergir sentidos que contribuam para problematizar conhecimentos produzidos no âmbito dos componentes curriculares do Curso de Pedagogia.A apresentação na II MEPEC está organizada em torno de quatro temas:-Vida de assentado: breve história, as lutas e conquistas, a situação atual…-O Campus avançado do IFC em Abelardo Luz;-Escola do/no campo: o ensino fundamental (as escolas municipais);-Escola do/no campo: o ensino médio (as escolas estaduais).No decorrer da apresentação dos temas serão utilizadas imagens (fotos) e entrevistas realizadas com pessoas do local, para o que se fará necessário contar com Datashow e computador e razão pela qual haverá mais de um expositor
OFICINAS DO BRINCAR: UM RESGATE A INFÂNCIA POR MEIO DE JOGOS, BRINQUEDOS E BRINCADEIRAS. (relato de experiência)
A brincadeira e jogo são construções sociais e, portanto culturais. A criança ao nascer está impregnada de práticas estabelecidas nas relações com outros sujeitos, adultos e outras crianças que possibilitam o acesso aos códigos sociais estabelecidos na forma de aprendizagem social. É na brincadeira, na fantasia e posteriormente no jogo com a elaboração de regras mais complexas que a criança se apropria da organização social na qual está inserida. Como processo cultural, o acesso a brincadeira e ao jogo se dá fundamentalmente na relação com outro e com as condições de espaço, materiais e possibilidades de exploração desses elementos. Considerando a importância da brincadeira e do jogo em proposições criativas, de descobertas, elaborações ereelaborações, estamos realizando um projeto de pesquisa denominado “Oficinas do brincar: um resgate a infância por meio de jogos, brinquedos e brincadeiras”, desenvolvido com os acadêmicos da quarta fase do curso de Licenciatura em Pedagogia, do Instituto Federal Catarinense – campi Blumenau (SC), com a perspectiva de propiciar espaço de relacionamento significativo com a brincadeira, o jogo, o brinquedo e práticas corporais expressivas como elementos de acesso a cultura lúdica e, portanto de inserção num contexto social humanizador. A dinâmica do projeto compreende atividades sequenciais com os discentes, semanalmente, nos quais são utilizadas as dependências da própria instituição, que disponibiliza o espaço físico e conta com a colaboração dos estudantes ao trazerem os recursos - como brinquedos, jogos e materiais para práticas corporais e expressivas. O projeto está em fase inicial de desenvolvimento, mas vem confirmando a relevância de seus propósitos, haja visto que parte do princípio de propiciar resgate e vivências da infância, do brincar, através dos jogos, brinquedos e brincadeiras, tematizando discussões em torno da ludicidade, como processo histórico e social, capaz de proporcionar reflexão e colaborar com a formação humana pelo acesso e interação com essas formas de manifestação da cultura. Dessa forma, objetiva-se com esta oficina, propiciar espaço e oportunidades de autoconhecimento, vivências inclusivas, melhora da auto-estima, desenvolver habilidades de comunicação, expressão e interação social dos acadêmicos envolvidos no projeto com os sujeitos participantes, colaborando com a formação acadêmica dos alunos mediadores do projeto tanto no que se refere à prática pedagógica exercida sob a perspectiva de professor, intelectual-pesquisador, bem como para a comunidade envolvida, no sentido de poder recordar os jogos, brinquedos e brincadeiras de suas infâncias por meio de cantos temáticos (num estande ou sala de aula), contendo: mostra do acervo de brinquedos que fizeram parte da infância da turma; produção artesanal de brinquedos sustentáveis com matérias recicláveis; espaço do faz de conta, com oficineiros desenvolvendo atividades recreacionistas para o público visitante
Anaerobic ammonium-oxidising bacteria: A biological source of the bacteriohopanetetrol stereoisomer in marine sediments
Bacterially-derived bacteriohopanepolyols (BHPs) are abundant, well preserved lipids in modern and paleo-environments. Bacteriohopanetetrol (BHT) is a ubiquitously produced BHP while its less common stereoisomer (BHT isomer) has previously been associated with anoxic environments; however, its biological source remained unknown. We investigated the occurrence of BHPs in Golfo Dulce, an anoxic marine fjord-like enclosure located in Costa Rica. The distribution of BHT isomer in four sediment cores and a surface sediment transect closely followed the distribution of ladderane fatty acids, unique biomarkers for bacteria performing anaerobic ammonium oxidation (anammox). This suggests that BHT isomer and ladderane lipids likely shared the same biological source in Golfo Dulce. This was supported by examining the BHP lipid compositions of two enrichment cultures of a marine anammox species ('. Candidatus Scalindua profunda'), which were found to contain both BHT and BHT isomer. Remarkably, the BHT isomer was present in higher relative abundance than BHT. However, a non-marine anammox enrichment contained only BHT, which explains the infrequence of BHT isomer observations in terrestrial settings, and indicates that marine anammox bacteria are likely responsible for at least part of the environmentally-observed marine BHT isomer occurrences. Given the substantially greater residence time of BHPs in sediments, compared to ladderanes, BHT isomer is a potential biomarker for past anammox activity
First international descriptive and interventional survey for cholesterol and non-cholesterol sterol determination by gas- and liquid- chromatography–Urgent need for harmonisation of analytical methods
Serum concentrations of lathosterol, the plant sterols campesterol and sitosterol and the cholesterol metabolite 5α-cholestanol are widely used as surrogate markers of cholesterol synthesis and absorption, respectively. Increasing numbers of laboratories utilize a broad spectrum of well-established and recently developed methods for the determination of cholesterol and non-cholesterol sterols (NCS). In order to evaluate the quality of these measurements and to identify possible sources of analytical errors our group initiated the first international survey for cholesterol and NCS. The cholesterol and NCS survey was structured as a two-part survey which took place in the years 2013 and 2014. The first survey part was designed as descriptive, providing information about the variation of reported results from different laboratories. A set of two lyophilized pooled sera (A and B) was sent to twenty laboratories specialized in chromatographic lipid analysis. The different sterols were quantified either by gas chromatography-flame ionization detection, gas chromatography- or liquid chromatography-mass selective detection. The participants were requested to determine cholesterol and NCS concentrations in the provided samples as part of their normal laboratory routine. The second part was designed as interventional survey. Twenty-two laboratories agreed to participate and received again two different lyophilized pooled sera (C and D). In contrast to the first international survey, each participant received standard stock solutions with defined concentrations of cholesterol and NCS. The participants were requested to use diluted calibration solutions from the provided standard stock solutions for quantification of cholesterol and NCS. In both surveys, each laboratory used its own internal standard (5α-cholestane, epicoprostanol or deuterium labelled sterols).
Main outcome of the survey was, that unacceptably high interlaboratory variations for cholesterol and NCS concentrations are reported, even when the individual laboratories used the same calibration material. We discuss different sources of errors and recommend all laboratories analysing cholesterol and NCS to participate in regular quality control programs
- …