924 resultados para National Endowment for the Humanities. Division of State Programs
Resumo:
The spatial and temporal distribution of organisms is a fundamental aspect of biological communities. The present study focused on three remnants of arboreal Caatinga in northeastern Brazil between May, 2009 and April, 2010. A total of 627 euglossine males were captured in traps baited with artificial aromatic compounds. The specimens belonged to 14 species and four genera: Euglossa Latreille, Eulaema Lepeletier, Eufriesea Cockerell, and Exaerete Hoffmannsegg. Eulaema nigrita Lepeletier (41.6), Euglossa carolina Nem,sio (15.3%), Eulaema marcii Nem,sio (13.6%), and Euglossa melanotricha Moure (12.8%) were the most common species sampled. The distribution of collected specimens per fragment was as follows: BraA(0)na (280 ha)-259 individuals belonging to 14 species; Cambui (179 ha)-161 individuals from eight species; and Pindoba (100 ha)-207 individuals represented by seven species. BraA(0)na had the highest diversity (H'aEuro parts per thousand= 1.91) and estimated species richness. The largest fragment was the main source of the observed variation in species richness and abundance, indicating a non-random pattern of spatial distribution. The analysis of environmental factors indicated that seasonal variation in these factors was the principal determinant of species occurrence and abundance.
Resumo:
Increased plasma osmolality by food intake evokes augmentation of plasma oxytocin (OT). Ovarian steroids may also influence the balance of body fluids by acting on OT neurones. Our aim was to determine if estrogen influences the activity of OT neurones in paraventricular nucleus (PVN) and supraoptic nucleus (SON) under different osmotic situations. Ovariectomized rats (OVX) were treated with either estradiol (E-2) or vehicle and were divided into three groups: group I was fed ad libitum, group II underwent 48 h of fasting, and group III was refed after 48 h of fasting. On the day of the experiment, blood samples were collected to determine the plasma osmolality and OT. The animals were subsequently perfused, and OT/FOS immunofluorescence analysis was conducted on neurones in the PVN and the SON. When compared to animals which were fasted or fed ad libitum, the plasma osmolality of refed animals was higher, regardless of whether they were treated with vehicle or E-2. We observed neural activation of OT cells in vehicle-or E-2-treated OVX rats refed after 48 h of fasting, but not in animals fed ad libitum or in animals that only underwent 48 h of fasting. Finally, the percentage of neurones that co-expressed OT and FOS was lower in both the PVN and the SON of animals treated with E-2 and refed, when compared to vehicle-treated animals. These results suggest that E-2 may have an inhibitory effect on OT neurones and may modulate the secretion of OT in response to the increase of osmolality induced by refeeding. Journal of Endocrinology (2012) 212, 129-138
Resumo:
During a half-day symposium, the topic 'Channels and Transporters' was covered with five lectures, including a presentation on 'Introduction and Basics of Channels and Transporters' by Beat Ernst, lectures on structure, function and physiology of channels and transporters ('The Structural Basis for Ion Conduction and Gating in Pentameric Ligand-Gated Ion Channels' by Raimund Dutzler and 'Uptake and Efflux Transporters for Endogenous Substances and for Drugs' by Dietrich Keppler), and a case study lecture on 'Avosentan' by Werner Neidhart. The program was completed by Matthias Hediger who introduced to the audience the National Center of Competence in Research (NCCR)-TransCure in his lecture entitled 'From Transport Physiology to Identification of Therapeutic Targets'.
Resumo:
This article examines the relations between the Turkish State Planning Organisation (SPO) and the Western economic system during the first two decades of national planning in Turkey (1960–1980). It traces how the SPO, established with the guidance and full endorsement of international economic institutions came to vehemently oppose Turkish participation in one of their pillars: the European Economic Community (EEC), the predecessor of the European Union. It argues that the shift in the SPO's world-view was founded upon two distinct understandings of the Turkish nation and its development, situates these understandings within the intellectual history of Turkey's past ambivalence towards the West, and, in doing so, provides a historical case-study of the ideological clash between modernisation and dependency theories of development.
Resumo:
This article examines the relations between the Turkish State Planning Organisation (SPO) and the Western economic system during the first two decades of national planning in Turkey (1960-1980). It traces how the SPO, established with the guidance and full endorsement of international economic institutions came to vehemently oppose Turkish participation in one of their pillars: the European Economic Community (EEC), the predecessor of the European Union. It argues that the shift in the SPO's world-view was founded upon two distinct understandings of the Turkish nation and its development, situates these understandings within the intellectual history of Turkey's past ambivalence towards the West, and, in doing so, provides a historical case-study of the ideological clash between modernisation and dependency theories of development.
Resumo:
Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional
Resumo:
Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional
Resumo:
Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional
Resumo:
This paper aims to capture the changing features of local SOEs under the national SOE restructuring program in the 2000s. The national policy on SOE reform in this phase had an effect of considerably clarifying and narrowing down the raison d'être of SOEs, which has been put into practice at the local level through provincial master plans. Consequently, some signs of an important change are observed: the structure of the local SOE sector is being standardized to a certain extent, and the remaining local SOEs are becoming more geared to the needs of a market economy. This trend would have far-reaching implications for the policy implementation and public service delivery by localities, which in turn would affect the long-term development of non-state sectors.
Resumo:
The semiempirical PM3 method, calibrated against ab initio HF/6–31+G(d) theory, has been used to elucidate the reaction of 1,2-dichloroethane (DCE) with the carboxylate of Asp-124 at the active site of haloalkane dehalogenase of Xanthobacter autothropicus. Asp-124 and 13 other amino acid side chains that make up the active site cavity (Glu-56, Trp-125, Phe-128, Phe-172, Trp-175, Leu-179, Val-219, Phe-222, Pro-223, Val-226, Leu-262, Leu-263, and His-289) were included in the calculations. The three most significant observations of the present study are that: (i) the DCE substrate and Asp-124 carboxylate, in the reactive ES complex, are present as an ion-molecule complex with a structure similar to that seen in the gas-phase reaction of AcO− with DCE; (ii) the structures of the transition states in the gas-phase and enzymatic reaction are much the same where the structure formed at the active site is somewhat exploded; and (iii) the enthalpies in going from ground states to transition states in the enzymatic and gas-phase reactions differ by only a couple kcal/mol. The dehalogenase derives its catalytic power from: (i) bringing the electrophile and nucleophile together in a low-dielectric environment in an orientation that allows the reaction to occur without much structural reorganization; (ii) desolvation; and (iii) stabilizing the leaving chloride anion by Trp-125 and Trp-175 through hydrogen bonding.
Resumo:
Cell–cell recognition and patterning of cell contacts have a critical role in mediating reversible assembly of a variety of transcellular complexes in the nervous system. This study provides evidence for regulation of cell interactions through modulation of ankyrin binding to neurofascin, a member of the L1CAM family of nervous system cell adhesion molecules. The phosphorylation state of the conserved FIGQY tyrosine in the cytoplasmic domain of neurofascin regulates ankyrin binding and governs neurofascin-dependent cell aggregation as well as cell sorting when neurofascin is expressed in neuroblastoma cells. These findings suggest a general mechanism for the patterning of cell contact based on external signals that regulate tyrosine phosphorylation of L1CAM members and modulate their binding to ankyrin.
Resumo:
Positioning of the Z ring at the midcell site in Escherichia coli is assured by the min system, which masks polar sites through topological regulation of MinC, an inhibitor of division. To study how MinC inhibits division, we have generated a MalE-MinC fusion that retains full biological activity. We find that MalE-MinC interacts with FtsZ and prevents polymerization without inhibiting FtsZ's GTPase activity. MalE-MinC19 has reduced ability to inhibit division, reduced affinity for FtsZ, and reduced ability to inhibit FtsZ polymerization. These results, along with MinC localization, suggest that MinC rapidly oscillates between the poles of the cell to destabilize FtsZ filaments that have formed before they mature into polar Z rings.
Resumo:
We report the isolation and expression of the Hox gene, Cnox-2, in Hydractinia symbiolongicarpus, a hydrozoan displaying division of labor. We found different patterns of aboral-to-oral Cnox-2 expression among polyp polymorphs, and we show that experimental conversion of one polyp type to another is accompanied by concordant alteration in Cnox-2 expression. Our results are consistent with the suggestion that polyp polymorphism, characteristic of hydractiniid hydroids, arose via evolutionary modification of proportioning of head to body column.
Resumo:
Time-resolved excited-state absorption intensities after direct two-photon excitation of the carotenoid S1 state are reported for light-harvesting complexes of purple bacteria. Direct excitation of the carotenoid S1 state enables the measurement of subsequent dynamics on a fs time scale without interference from higher excited states, such as the optically allowed S2 state or the recently discovered dark state situated between S1 and S2. The lifetimes of the carotenoid S1 states in the B800-B850 complex and B800-B820 complex of Rhodopseudomonas acidophila are 7 ± 0.5 ps and 6 ± 0.5 ps, respectively, and in the light-harvesting complex 2 of Rhodobacter sphaeroides ≈1.9 ± 0.5 ps. These results explain the differences in the carotenoid to bacteriochlorophyll energy transfer efficiency after S2 excitation. In Rps. acidophila the carotenoid S1 to bacteriochlorophyll energy transfer is found to be quite inefficient (φET1 <28%) whereas in Rb. sphaeroides this energy transfer is very efficient (φET1 ≈80%). The results are rationalized by calculations of the ensemble averaged time constants. We find that the Car S1 → B800 electronic energy transfer (EET) pathway (≈85%) dominates over Car S1 → B850 EET (≈15%) in Rb. sphaeroides, whereas in Rps. acidophila the Car S1 → B850 EET (≈60%) is more efficient than the Car S1 → B800 EET (≈40%). The individual electronic couplings for the Car S1 → BChl energy transfer are estimated to be approximately 5–26 cm−1. A major contribution to the difference between the energy transfer efficiencies can be explained by different Car S1 energy gaps in the two species.
Resumo:
We studied the electronically excited state of the isolated reaction center of photosystem II with high-resolution fluorescence spectroscopy at 5 K and compared the obtained spectral features with those obtained earlier for the primary electron donor. The results show that there is a striking resemblance between the emitting and charge-separating states in the photosystem II reaction center, such as a very similar shape of the phonon wing with characteristic features at 19 and 80 cm−1, almost identical frequencies of a number of vibrational modes, a very similar double-Gaussian shape of the inhomogeneous distribution function, and relatively strong electron-phonon coupling for both states. We suggest that the emission at 5 K originates either from an exciton state delocalized over the inactive branch of the photosystem or from a fraction of the primary electron donor that is long-lived at 5 K. The latter possibility can be explained by a distribution of the free energy difference of the primary charge separation reaction around zero. Both possibilities are in line with the idea that the state that drives primary charge separation in the reaction center of photosystem II is a collective state, with contributions from all chlorophyll molecules in the central part of the complex.