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Search Results: 1 - 10 of 219617 matches for " C Cremer "
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Rise, fall and resurrection of chromosome territories: a historical perspective Part II. Fall and resurrection of chromosome territories during the 1950s to 1980s. Part III. Chromosome territories and the functional nuclear architecture: experiments and m
T Cremer,C Cremer
European Journal of Histochemistry , 2006, DOI: 10.4081/995
Abstract: Part II of this historical review on the progress of nuclear architecture studies points out why the original hypothesis of chromosome territories from Carl Rabl and Theodor Boveri (described in part I) was abandoned during the 1950s and finally proven by compelling evidence forwarded by laser-uvmicrobeam studies and in situ hybridization experiments. Part II also includes a section on the development of advanced light microscopic techniques breaking the classical Abbe limit written for readers with little knowledge about the present state of the theory of light microscopic resolution. These developments have made it possible to perform 3D distance measurements between genes or other specifically stained, nuclear structures with high precision at the nanometer scale. Moreover, it has become possible to record full images from fluorescent structures and perform quantitative measurements of their shapes and volumes at a level of resolution that until recently could only be achieved by electron microscopy. In part III we review the development of experiments and models of nuclear architecture since the 1990s. Emphasis is laid on the still strongly conflicting views about the basic principles of higher order chromatin organization. A concluding section explains what needs to be done to resolve these conflicts and to come closer to the final goal of all studies of the nuclear architecture, namely to understand the implications of nuclear architecture for nuclear functions.
Rise, fall and resurrection of chromosome territories: a historical perspective. Part I. The rise of chromosome territories
T Cremer,C Cremer
European Journal of Histochemistry , 2006, DOI: 10.4081/989
Abstract: It is now generally accepted that chromosomes in the cell nucleus are organized in distinct domains, first called chromosome territories in 1909 by the great cytologist Theodor Boveri. Yet, even today chromosomes have remained enigmatic individuals, whose structures, arrangements and functions in cycling and post-mitotic cells still need to be explored in full detail. Whereas numerous recent reviews describe present evidence for a dynamic architecture of chromosome territories and discuss the potential significance within the functional compartmentalization of the nucleus, a comprehensive historical account of this important concept of nuclear organization was lacking so far. Here, we describe the early rise of chromosome territories within the context of the discovery of chromosomes and their fundamental role in heredity, covering a period from the 1870th to the early 20th century (part I, this volume). In part II (next volume) we review the abandonment of the chromosome territory concept during the 1950th to 1980th and the compelling evidence, which led to its resurrection during the 1970th to 1980th.
Distribution, abundance and density estimates of franciscanas, Pontoporia blainvillei (Cetacea: Pontoporiidae), in Babitonga bay, southern Brazil
Cremer, Marta J.;Sim?es-Lopes, Paulo C.;
Revista Brasileira de Zoologia , 2008, DOI: 10.1590/S0101-81752008000300003
Abstract: pontoporia blainvillei (gervais & d'orbigny, 1844) is threatened throughout its distribution. the species can be found year-round in the babitonga bay estuary (26o 02'-26o 28's and 48o28'-48o50'w), in the north coast of the state of santa catarina, brazil. boat surveys were conducted in order to evaluate its abundance and density between 2000 and 2003. sampling was random and stratified, with 46 transects in five sub-areas, comprising a total area of 160 km2. data collection was conducted following the linear transect method with distance sampling. a total of 1174.7 km was scanned and 38 groups were observed. franciscanas were not uniformly distributed in babitonga bay. group size ranged from one to 13 animals (mean ± sd = 5.02 ± 3.62). model 1 (half-normal) showed the best fit to the data. the estimated population size was 50 animals and the density was 0.32 individuals km-2. density estimates evaluated in the sub-areas where franciscanas occurred resulted in a density of 0.46 individuals km-2. monitoring this population is of considerable importance due to the constant threats that this species faces in this bay.
The occurrence of Pontoporia blainvillei (Gervais & d'Orbigny) (Cetacea, Pontoporiidae) in an estuarine area in southern Brazil
Cremer, Marta J.;Sim?es-Lopes, Paulo C.;
Revista Brasileira de Zoologia , 2005, DOI: 10.1590/S0101-81752005000300032
Abstract: the toninha, or franciscana, pontoporia blainvillei (gervais & d'orbigny, 1844), is an endemic species of cetacean of the southwestern atlantic ocean. there is little information on the occurrence of this species in its natural environment due to the great difficulty in sighting it. systematized and non-systematized observations of franciscanas were made from december 1996 through november 2001 at babitonga bay, on the northern coast of santa catarina state, southern brazil. the observations were made from small motorboats. a total of 79 observations were made, totaling 561 individuals. up to 59.5% of the groups consisted of over four individuals and the average group size was seven. calves were present in 30.4% of the observations. the species was found throughout the year within the bay and preferential areas were identified. calves were registered during all seasons. data are presented on the behavior (feeding, traveling, aerial behavior and behavior relating to the boats) and on inter-specific interactions with terns, cormorants [phalacrocorax brasilianus (gmelin, 1789)] and brown boobies [sula leucogaster (boddaert, 1783)]. the species is sympatric with the estuarine dolphin sotalia guianensis (p. j. van bénéden, 1864) in the bay, but there was no record of interaction between them. the area of the bay represents an important refuge for the franciscana species.
Diversidade e abundancia sazonal da avifauna em duas planícies de maré no estuário da baía da Babitonga, norte de Santa Catarina Diversity and abundance of birds in two tidal flat in Babitonga Bay estuary, north of Santa Catarina state, Brazil
Alexandre V. Grose,Cristiane C. Hillebrant,Marta J. Cremer
Iheringia. Série Zoologia , 2013,
Abstract: Informa es sobre a ocorrência de aves nos ambientes estuarinos de Santa Catarina ainda s o escassas. O objetivo deste trabalho foi registrar a diversidade, abundancia e varia o sazonal das aves em duas planícies de maré na baía da Babitonga. As amostragens foram realizadas durante um ano (maio de 2006 a abril 2007). No total foram identificadas 25 espécies, sendo 15 no Linguado (LG) e 24 na desembocadura do Monte de Trigo (MT). Apenas uma espécie foi exclusiva no LG Himantopus melanurus (Vieillot, 1817), enquanto dez espécies ocorreram apenas no MT. O número de espécies em MT foi superior ao encontrado em LG. A espécie mais abundante em MT foi Rynchops niger (Linnaeus, 1758) e em LG foi Egretta caerulea (Linnaeus, 1758). Durante alguns meses foram registradas espécies migratórias neárticas em ambas as áreas, o que representou um acréscimo na diversidade. A extensa planície de maré formada pelo fechamento do canal do Linguado tem sido muito ocupada por aves, possivelmente pela maior disponibilidade de alimento. Information of birds in estuaries of Santa Catarina is scarce. This work aimed to collect data on diversity, abundance and seasonal variation on this community. Sampling of birds in two tidal flats in Babitonga Bay estuary was carried out during one year (May 2006 to April 2007). A total of 25 species were identified, being 15 in Linguado (LG) and 24 in Monte de Trigo (MT). Only one species was unique in LG (Himantopus melanurus Vieillot, 1817) and 10 in MT. The number of species in MT was higher than in LG due to the conservation condition. The most abundant species on MT was the Black Skimmer [Rynchops niger (Linnaeus, 1758)] and in the LG was the Little Blue Heron [Egretta caerulea (Linnaeus, 1758)]. During some months Nearctic migratory species were recorded in both areas, representing an increase in diversity. The extensive tidal flat formed by the closure of the channel in LG is widely used by birds, possibly because of increased food availability.
Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae) and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae) in an estuarine environment in southern Brazil
Cremer, Marta J.;Pinheiro, Pedro C.;Sim?es-Lopes, Paulo C.;
Iheringia. Série Zoologia , 2012, DOI: 10.1590/S0073-47212012000200003
Abstract: the present study provides information about the diet of sympatric populations of small cetaceans in the babitonga bay estuary. this is the first study on the diet of these species in direct sympatry. the stomach contents of seven guiana dolphins sotalia guianensis and eight franciscanas pontoporia blainvillei were analyzed. the prey of both cetaceans was mostly teleost fishes, followed by cephalopods. we identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of guiana dolphins. lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. stellifer rastrifer and gobionellus oceanicus were also important for franciscana, so as mugil curema and micropogonias furnieri were important for guiana dolphins. stellifer rastrifer and cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%), while achirus lineatus, c. edentulus, s. brasiliensis, cynoscion leiarchus, m. furnieri, m. curema, diapterus rhombeus, eugerres brasilianus and g. oceanicus showed 28.6% of frequency of occurrence for guiana dolphins. franciscanas captured greater cephalopods than the guiana dolphins in both total length (z= -3.38; n= 40; p< 0.05) and biomass (z = -2.46; n = 40; p<0.05). all of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the babitonga bay for these cetacean populations.
Occupation pattern of a harbor inlet by the estuarine dolphin, Sotalia guianensis (P. J. Van Bénéden, 1864) (Cetacea, Delphinidae)
Cremer, Marta Jussara;Sim?es-Lopes, Paulo César;Pires, José Salatiel Rodrigues;
Brazilian Archives of Biology and Technology , 2009, DOI: 10.1590/S1516-89132009000300029
Abstract: the occupation pattern of sotalia guianensis in s?o francisco do sul harbor inlet, in babitonga bay, southern brazil, was studied between september 1996 and june 1998. a total of 200 h of naturalistic observations and 141.2 h of estuarine dolphin systematic observations were made using binoculars 7 x 50. at each three minutes interval, data about number of individuals and behavior were registered. the population used the harbor inlet intensively, mainly for fishing activities. ebb tide was responsible for a higher occupation index. considering the months analyzed, the higher occupation index occurred in may, and in january the lower occurrence was observed. the mean group size was four individuals.
An NFKB1 Promoter Insertion/Deletion Polymorphism Influences Risk and Outcome in Acute Respiratory Distress Syndrome among Caucasians
Ednan K. Bajwa,Paul C. Cremer,Michelle N. Gong,Rihong Zhai,Li Su,B. Taylor Thompson,David C. Christiani
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019469
Abstract: Nuclear factor-κB (NF-κB) is required for transcription of many pro-inflammatory genes and has been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS). We hypothesized that a known functional polymorphism in the promoter of the NFKB1 gene may affect susceptibility to and outcome from ARDS.
Bonding in Mercury-Alkali Molecules: Orbital-driven van der Waals Complexes
Elfi Kraka,Dieter Cremer
International Journal of Molecular Sciences , 2008, DOI: 10.3390/ijms9060926
Abstract: The bonding situation in mercury-alkali diatomics HgA (2Σ+) (A = Li, Na, K, Rb) has been investigated employing the relativistic all-electron method Normalized Elimination of the Small Component (NESC), CCSD(T), and augmented VTZ basis sets. Although Hg,A interactions are typical of van der Waals complexes, trends in calculated De values can be explained on the basis of a 3-electron 2-orbital model utilizing calculated ionization potentials and the De values of HgA+(1Σ+) diatomics. HgA molecules are identified as orbital-driven van der Waals complexes. The relevance of results for the understanding of the properties of liquid alkali metal amalgams is discussed.
Extension of the Karplus Relationship for NMR Spin-Spin Coupling Constants to Nonplanar Ring Systems: Pseudorotation of Tetrahydrofuran
Anan Wu,Dieter Cremer
International Journal of Molecular Sciences , 2003, DOI: 10.3390/i4040158
Abstract: coming soon
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