Anticipated Synchronization in a Biologically Plausible Model of Neuronal Motifs

Two identical autonomous dynamical systems coupled in a master-slave configuration can exhibit anticipated synchronization (AS) if the slave also receives a delayed negative self-feedback. Recently, AS was shown to occur in systems of simplified neuron models, requiring the coupling of the neuronal membrane potential with its delayed value. However, this coupling has no obvious biological correlate. Here we propose a canonical neuronal microcircuit with standard chemical synapses, where the delayed inhibition is provided by an interneuron. In this biologically plausible scenario, a smooth transition from delayed synchronization (DS) to AS typically occurs when the inhibitory synaptic conductance is increased. The phenomenon is shown to be robust when model parameters are varied within physiological range. Since the DS-AS transition amounts to an inversion in the timing of the pre- and post-synaptic spikes, our results could have a bearing on spike-timing-dependent-plasticity models

DSM and cultural diversity

Abstract presented at The 14th Pacific Rim College of Psychiatrists Scientific Meeting, 28-30 October 2010, Brisbane, Australi

Domination, development, and drought: A study of two Chikunda settlements in Dande, Zambesi Valley, Zimbabwe.

The principle theme of this study is an examination of the relationship between political and economic domination, and development and drought in the Dande area of the Zambesi Valley, Zimbabwe. To this end, two settlements, a centralised polity and an area of shallow and dispersed lineages, were researched and compared. While the populations of these areas comprised different clans and lineages, particular attention is paid to the Chikunda group whose dominant clan in Dande, the marunga rosario andrade, controlled a longstanding centralised chieftaincy. Political process in Dande was until the 1990s viewed as the performance of two forms of chieftaincy, autochthonous and conquering. Autochthonous chiefs were believed to be supported by the people and to act in benevolent ways, while conquering chiefs were expected to act in the interests of their own clan and lineage. Particular attention is paid to the issue of chieftaincy through an examination of the formation of centralised Chikunda polities which derived from a Portuguese land tenure system. Accounts of marunga conquest of Dande and the Chapoto chieftaincy of the 1990s are examined with regard to domination. In comparison, the importance of land spirits in the discourse of chieftaincy is highlighted in terms of centralised and decentralised polities. While the significance of chieftaincy as a political discourse in Dande was high, during the 1990s the introduction of state policies of structural adjustment and development altered political and economic practices. Serious drought in 1991-92 exacerbated longstanding inter-generational conflict which led to a split of outlook on issues of kinship, political organisation, and livelihood practices. The occurrence of serious drought and associated hunger and illness, coupled with social pressures brought by development, caused local populations to express the belief that the Zimbabwean state, which had been installed through the will of the people, was no longer for the people. The trajectory of the Zimbabwean state from its role as autochthonous ruler to that of conqueror in little over a decade after Independence is examined through discussion of land spirit ceremonies performed during and after drought

Acción anti-fúngica del extracto de cuesco de olivo sobre hongos fitopatógenos. Evaluación in vitro

38 p.Las enfermedades “cancro del tallo”, “tizón temprano”, “moho gris” y “marchitez vascular” causada por los hongos Alternaria alternata, Alternaria solani, Botrytis cinerea y Fusarium oxysporum respectivamente, representan las principales patologías que afectan al cultivo del tomate en Chile, influyendo en su rendimiento y originando considerables pérdidas económicas. De aquí la importancia de evaluar distintas alternativas de control cuantificando el efecto inhibitorio in vitro de diferentes tratamientos sobre estos hongos fitopatógenos obtenidos de tomate. El estudio fue llevado a cabo en el Laboratorio de Sanidad Vegetal de la Universidad de Talca, realizándose la aislación de los hongos de plantas de tomate que presentaron síntomas de cancro del tallo, tizón temprano, moho gris y marchitez vascular. El objetivo principal fue determinar la efectividad in vitro de extractos del cuesco de olivo sobre el control de aislados fungosos de Alternaria alternata, Alternaria solani, Botrytis cinerea y Fusarium oxysporum. Además se incluyó un control a modo de comparación, correspondiente a un fungicida comercial (azoxystrobin + cloratalonilo). La dosis del extracto de cuesco de olivo evaluada fue al 10% y al 20%, la dosis del control positivo fue a 0,8 LKg/ ha-hl. Se incluyó un tratamiento control negativo (Agua), en el que no se aplicó ningún anti fúngico al medio de cultivo APD. Las evaluaciones se realizaron a las 48, 72 y 96 horas luego de sembrado el patógeno, midiendo el área de crecimiento de los diferentes tratamientos. El extracto de cuesco de olivo 20% y el tratamiento correspondiente a azoxystrobin+cloratalonilo, presentaron un mayor efecto inhibitorio sobre Alternaria alternata, Alternaria solani, Botrytis cinerea y Fusarium oxysporum. Por otra parte, el tratamiento extracto de cuesco de olivo 10%, presentó un mayor efecto inhibitorio sobre los hongos, Alternaria solani y Fusarium oxysporum, resultando menos eficiente, pero igualmente distinto del tratamiento testigo con agua, en los hongos Alternaria alternata y Botrytis cinerea. / ABSTRACT:The diseases "stem canker", "early blight", "gray mold" and "vascular wilt" caused by the fungi Alternaria alternata, Alternaria solani, Botrytis cinerea and Fusarium oxysporum respectively, represent the main pathologies that affect tomatoes cultivation in Chile, influencing its performance and also causing economic losses. To evaluate different control alternatives quantifying the inhibitory effect in vitro of different treatments on these phytopathogenic fungi obtained from tomatoes is very importat. The study was carried out on the Plant Protection Laboratory of the University of Talca, where fungi from tomato plants that showed symptoms of stem cancer, early blight, gray mold and vascular wilt were isolated. The main objective of this study was to determine the in vitro effectiveness of extracts of the olive leaf on the control of fungal isolates of Alternaria alternata, Alternaria solani, Botrytis cinerea and Fusarium oxysporum. In addition, a control was included for comparison, corresponding to a commercial fungicide (azoxystrobin + chloratalonyl). Moreover, the dose of the olive extract was evaluated at 10% and 20%, the dose of the positive control was 0.8 L-kg / ha-hl. A negative control treatment (Water) was included, in which no antifungal was applied to the PDA culture medium. The evaluations were made out at 48, 72 and 96 hours after the pathogen were planted, measuring the growth area of different treatments. The 20% olive extract and the treatment of azoxystrobin + chloratalonil had a greater inhibitory effect on Alternaria alternata, Alternaria solani, Botrytis cinerea and Fusarium oxysporum. On the other hand, the treatment of 10% olive extract, showed a greater inhibitory effect on the fungi, Alternaria solani and Fusarium oxysporum, but less efficient, and also different from the control treatment with water, in the fungi Alternaria alternata and Botrytis cinerea

Uma Análise Bakhtiniana dos Enunciados sobre o Efeito Fotoelétrico em Livros Didáticos do Ensino Superior

Apresenta-se uma análise bakhtiniana dos enunciados sobre Efeito Fotoelétrico encontrados em três livros didáticos de Ensino Superior. Avaliaram-se vozes do artigo original de Einstein que são veiculadas e que são silenciadas nos livros, identificando uma postura epistemológica que guia esse processo de privilegiação de vozes. Os resultados apontam que existe uma omissão das bases do artigo original fundadas na Termodinâmica e na Mecânica Estatística e do uso da Teoria de Wien. Por outro lado, há uma supervalorização do modelo de Planck sustentando um falso corte epistemológico entre Física Clássica e Moderna. Há uma privilegiação dos experimentos em detrimento das vozes que veiculam aspectos metafísicos utilizados no artigo original. Esses processos de veiculação e silenciamento de vozes aponta a sustentação de uma visão de mundo alinhada ao positivismo.Apresenta-se uma análise bakhtiniana dos enunciados sobre Efeito Fotoelétrico encontrados em três livros didáticos de Ensino Superior. Avaliaram-se vozes do artigo original de Einstein que são veiculadas e que são silenciadas nos livros, identificando uma postura epistemológica que guia esse processo de privilegiação de vozes. Os resultados apontam que existe uma omissão das bases do artigo original fundadas na Termodinâmica e na Mecânica Estatística e do uso da Teoria de Wien. Por outro lado, há uma supervalorização do modelo de Planck sustentando um falso corte epistemológico entre Física Clássica e Moderna. Há uma privilegiação dos experimentos em detrimento das vozes que veiculam aspectos metafísicos utilizados no artigo original. Esses processos de veiculação e silenciamento de vozes aponta a sustentação de uma visão de mundo alinhada ao positivismo

New amphiphilic amino acid derivatives for efficient DNA transfection in vitro

Nucleic acids-based therapies have recently developed as next-generationagents for treating and preventing viral infection, cancer, and genetic disorders,but their use is still limited due to its relatively poor delivery into targetedcells. We designed and synthesized new amphiphilic amino acid derivatives(cysteine-based) of low molecular weight, formed by the same pentapeptide(AG2: WWCOO) N-acylated, with different hydrophobic chains containingfrom 12 to 18 carbons, named AG2-Cn (N), which dimerize by oxidationin the presence of pLenti-CMV-GFP Puro plasmid (P) in the respectivegemini. We determined transfection efficiency, critical micelle concentration,particle size, ζ-potential and cytotoxicity for the derivatives obtained. Wefound that all the synthesized compounds were active for DNA delivery andhad greater ability to transfect CHO-K1 cells. In particular, AG2-C18 is apromising carrier for gene delivery because it showed no cytotoxicity and itsactivity was greater than or equal to the commercial actives currently used.Fil: Peña, Lucía Carolina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Argarañá, María Fernanda. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: de Zan, María Mercedes. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Giorello, Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Antuña, Sebastián. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Prieto, Claudio. Universidad Nacional del Litoral; ArgentinaFil: Veaute, Carolina Melania Isabel. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Muller, Diana. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Risk of Hypothermia in a New Olympic Event: the 10-km Marathon Swim

INTRODUCTION: There are no available data addressing the potential clinical risks of open-water swimming competitions. OBJECTIVE: Address the risks of hypothermia and hypoglycemia during a 10-km open-water swimming competition in order to alert physicians to the potential dangers of this recently-introduced Olympic event. METHODS: This was an observational cross-sectional study, conducted during a 10-km open-water event (water temperature 21ºC). The highest ranked elite open-water swimmers in Brazil (7 men, 5 women; ages 21±7 years old) were submitted to anthropometrical measurements on the day before competition. All but one athlete took maltodextrine ad libitum during the competition. Core temperature and capillary glycemia data were obtained before and immediately after the race. RESULTS: Most athletes (83%) finished the race with mild to moderate hypothermia (core temperature <35ºC). The body temperature drop was more pronounced in female athletes (4.2±0.7ºC vs. male: 2.7±0.8ºC; p=0.040). When data from the athlete who did not take maltodextrine was excluded, capillary glycemia increased among athletes (pre 86.6±8.9 mg/dL; post 105.5±26.9 mg/dL; p=0.014). Time to complete the race was inversely related to pre- competition body temperature in men (r=-0.802; p=0.030), while it was inversely correlated with the change in capillary glycemia in women (r=-0.898; p=0.038). CONCLUSION: Hypothermia may occur during open-water swimming events even in elite athletes competing in relatively warm water. Thus, core temperature must be a chief concern of any physician during an open-water swim event. Capillary glycemia may have positive effects on performance. Further studies that include more athletes in a controlled setting are warranted