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排序方式: 共有481条查询结果,搜索用时 343 毫秒
101.
Lescano AR Blazes DL Montano SM Moran Z Naquira C Ramirez E Lie R Martin GJ Lescano AG Zunt JR 《PloS one》2008,3(9):e3274
With the rapidly increasing number of health care professionals seeking international research experience, comes an urgent need for enhanced capacity of host country institutional review boards (IRB) to review research proposals and ensure research activities are both ethical and relevant to the host country customs and needs. A successful combination of distance learning, interactive courses and expert course instructors has been applied in Peru since 2004 through collaborations between the U.S. Naval Medical Research Center Detachment, the University of Washington and the Department of Clinical Bioethics of the National Institutes of Health to provide training in ethical conduct of research to IRB members and researchers from Peru and other Latin American countries. All training activities were conducted under the auspices of the Peruvian National Institute of Health (INS), Ministry of Health. To date, 927 people from 12 different Latin American countries have participated in several of these training activities. In this article we describe our training model. 相似文献
102.
Subtidal fouling assemblages usually consist of short-lived organisms. Colonisation sequences on man-made structures may thus be greatly affected by the temporal and spatial variability of propagule supply. This study explores the influence of seasonality on succession in the macrofouling assemblage of a Patagonian harbour (Argentina, Southwest Atlantic). Replicated artificial substrata were suspended horizontally and sampled at quarterly intervals during 1?year. The influence of seasonality on 1-year-old assemblages was further analysed using additional sets of replicated panels submersed at different seasons and collected 1?year later. Upper surfaces were always dominated by ephemeral algae, while lower surfaces exhibited high coverage of filter-feeding invertebrates. Regardless of submersion length, species richness was significantly higher on lower than on upper surfaces. A significant interaction between orientation and submersion length was found for the Shannon diversity index, meaning that temporal changes in diversity depended on substratum orientation. On the lower surfaces, diversity reached a maximum after 9?months and then declined, mainly due to extensive dislodgment of two species of ascidians. On algal-dominated upper surfaces, differences in structure of annual assemblages were due to seasonal changes in the abundance of ephemeral algae. This study shows that constancy or variability of 1-year-old assemblages whose development began at different seasons depended greatly on the life history of the organisms that settled and managed to persist on both surfaces, which in turn depended on substratum orientation. 相似文献
103.
104.
Fernando Messina Roxana Depardo Ricardo Negroni Mercedes Romero Laura Walker Alicia Arechavala Emmanuel Marín Cristina Canteros Gabriela Santiso 《Revista iberoamericana de micología》2018,35(1):59-61
The case of a 60 year old woman with hemoptysis and a thin-walled cavitary lesion at the upper lobe of the right lung is presented. The woman presented at the Mycology Unit of the Muñiz Hospital in Buenos Aires City 3 months after the beginning of her clinical manifestations. A hyaline micelial fungus with chlamido-arthroconidias was isolated from the bronchoalveolar lavage. Immunodiffusion and counter-immnunoelectrophoresis with coccidioidin and histoplasmin rendered positive results against both antigents, and skin tests with coccidioidin and histoplasmin were also positive with strong reactions. The isolated fungus was identified as Coccidioides posadasii at the National Microbiology Institute Carlos Malbrán, by means of a molecular technique. The patient was treated with itraconazole by oral route at a daily dose of 200 mg with good clinical response, but due to the persistence of the lung cavity, a surgical removal of the upper lobe of the right lung had to be scheduled. 相似文献
105.
Female preference for males that have exclusively marked or invaded territories depends on male presence and its identity in the subterranean rodent Ctenomys talarum
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María Sol Fanjul María Florencia Varas Roxana Rita Zenuto 《Ethology : formerly Zeitschrift fur Tierpsychologie》2018,124(8):579-590
Territorial scent‐marking provides chemical records of male competitive interactions that are available to females, who gain valuable information to assess and identify best quality partners. In this context, the solitary subterranean rodent tuco‐tuco (Ctenomys talarum) offers excellent possibilities to evaluate the effects of male exclusive scent‐marking of territories on female assessment. For evaluation, we used wild caught individuals of C. talarum, manipulated their scent marks within the territories in captive conditions and staged preference tests where females were able to choose between exclusive and invaded territories. The evaluation was performed in two scenarios considering the identity of the intruder scent mark: territories invaded by a strange male and territories invaded by a neighbour male. Females investigated the chemical cues deposited on the substrate of the exclusively marked territory more frequently. Next, females displayed equal interest to scent samples of both males presented in a Y‐maze. Finally, when females could gain access to both individually isolated males and their scent‐marked territories, they spent more time within invaded territories despite they visited them with the same frequency. Moreover, females tried to get in contact by scratching the mesh of the owner of the invaded territory more frequently. We found that females of C. talarum evaluate the homogeneity (exclusiveness) of scent marks within a male territory and then show preferences in relation to the identity of the intruder's scent –whether strange or neighbour. 相似文献
106.
E. affinis can adjust to temperature stress in a matter of hours. Adaptation is greater in a varying temperature than in a constant temperature, consistent with the estuarine habitat of this calanoid. The species has the capacity to adjust both in the short-term as individuals and also genetically over a number of generations. The adjustments have been examined at several levels of organization. In whole copepods the time an individual becomes comatose when exposed to a 32 °C temperature and increasing by 1/2 °C at 5 min. intervals, has been used as a repeatable assay and gives a good prediction of survival at 30 °C, the ecological limit of the species in Chesapeake bay, USA. At the molecular and cellular levels, two adaptive mechanisms which have been observed in temperature stressed copepods are the synthesis of novel proteins and phase changes in plasma membrane lipids. Both of these mechanisms have potential for further understanding the adaptation of Eurytemora to variable temperatures. They may also have application as indicators of sublethal stress. 相似文献
107.
108.
Mario Palma Elizabeth N. Riffo Tamaki Suganuma Michael P. Washburn Jerry L. Workman Roxana Pincheira Ariel F. Castro 《Journal of cellular biochemistry》2019,120(9):16088-16107
NUAK1 is a serine/threonine kinase member of the AMPK-α family. NUAK1 regulates several processes in tumorigenesis; however, its regulation and molecular targets are still poorly understood. Bioinformatics analysis predicted that the majority of NUAK1 localizes in the nucleus. However, there are no studies about the regulation of NUAK1 subcellular distribution. Here, we analyzed NUAK1 localization in several human cell lines, mouse embryo fibroblasts, and normal mouse tissues. We found that NUAK1 is located in the nucleus and also in the cytoplasm. Through bioinformatics analysis and studies comparing subcellular localization of wild type and NUAK1 mutants, we identified a conserved bipartite nuclear localization signal at the N-terminal domain of NUAK1. Based on mass spectrometry analysis, we found that NUAK1 interacts with importin-β members including importin-β1 (KPNB1), importin-7 (IPO7), and importin-9 (IPO9). We confirmed that importin-β members are responsible for NUAK1 nuclear import through the inhibition of importin-β by Importazole and the knockdown of either IPO7 or IPO9. In addition, we found that oxidative stress induces NUAK1 cytoplasmic accumulation, indicating that oxidative stress affects NUAK1 nuclear transport. Thus, our study is the first evidence of an active nuclear transport mechanism regulating NUAK1 subcellular localization. These data will lead to investigations of the molecular targets of NUAK1 according to its subcellular distribution, which could be new biomarkers or targets for cancer therapies. 相似文献
109.
Agustina Falibene Roxana Josens 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2008,194(5):491-500
Dynamics of fluid feeding has been deeply studied in insects. However, the ability to vary the nectar-intake rate depending
only on the carbohydrate deprivation has been clearly demonstrated only in Camponotus mus ants. When insect morphometry and fluid properties remain constant, changes in intake rate could only be attributed to variations
in sucking pump activity. Previous records of the electrical activity generated during feeding in C.
mus have revealed two different signal patterns: the regular (RP, frequencies: 2–5 Hz) and the irregular (IP, frequencies: 7–12 Hz). This work studies the mechanism underlying food intake-rate modulation in ants by analysing whether
these patterns are involved. Behaviour and electrical activity generated by ants at different starvation levels were analysed
during feeding on sucrose solutions. Ants were able to modulate the intake rate for a variety of sucrose concentrations (10,
40 and 60%w/w). The IP only occurred for 60% of solutions and its presence did not affect the intake rate. However, during
the RP generated under the starved state, we found frequencies up to 7.5 Hz. RP frequencies positively correlated with the
intake-rate for all sucrose concentrations. Hence, intake-rate modulation according to sugar deprivation is mainly achieved
by the ant’s ability to vary the pumping frequency. 相似文献
110.