1,480 research outputs found

    Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern

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    Bird species vary greatly in the duration of their annual complete feather molt. However, such variation is not well documented in birds from many biogeographic areas, which restricts our understanding of the diversification of molt strategies. Recent research has revealed that molt duration can be estimated in passerines from ptilochronology-based measurements of the growth rate of their tail feathers. We used this approach to explore how molt duration varied in 98 Nearctic species that have different migratory strategies and molt patterns. As previously documented for Palearctic species, migration was associated with a shortening of molt duration among species that molted during summer on their breeding range. However, molts of winter-molting migratory species were as long as those of summer-molting sedentary species, which suggests that winter molt also allows Nearctic migrants to avoid the temporal constraints experienced during summer. Our results also suggest that migratory species that undergo a stopover molt within the Mexican monsoon region have the shortest molt duration among all Nearctic passerines. Interestingly, and contrary to expectations from a potential tradeoff between molt duration and feather quality, observed variation in feather growth rate was positively correlated with differences in tail feather mass, which may be caused by differences among groups in the availability of resources for molting. We encourage the use of similar approaches to study the variation in molt duration in other geographic areas where knowledge of the evolution of molt is limited.

    Heterotrophic N2-fixation contributes to nitrogen economy of a common wetland sedge, Schoenoplectus californicus

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    A survey of the ecological variability within 52 populations of Schoenoplectus californicus (C.A. Mey.) Soják across its distributional range revealed that it is commonly found in nitrogen (N) limited areas, but rarely in phosphorus limited soils. We explored the hypothesis that S. californicus supplements its nitrogen demand by bacterial N2-fixation processes associated with its roots and rhizomes. We estimated N2-fixation of diazotrophs associated with plant rhizomes and roots from several locations throughout the species’ range and conducted an experiment growing plants in zero, low, and high N additions. Nitrogenase activity in rhizomes and roots was measured using the acetylene reduction assay. The presence of diazotrophs was verified by the detection of the nifH gene. Nitrogenase activity was restricted to rhizomes and roots and it was two orders of magnitude higher in the latter plant organs (81 and 2032 nmol C2H4 g DW-1 d-1, respectively). Correspondingly, 40x more nifH gene copies were found on roots compared to rhizomes. The proportion of the nifH gene copies in total bacterial DNA was positively correlated with the nitrogenase activity. In the experiment, the contribution of fixed N to the plant N content ranged from 13.8% to 32.5% among clones from different locations. These are relatively high values for a non-cultivated plant and justify future research on the link between N-fixing bacteria and S. californicus production

    A város peremén. (A rozsdaövezet múltja és jelene Budapesten) = At the outskirts of the city. (Past and Present of the brownfield area in Budapest)

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    A barnamezős térség - ahol korábban elsősorban ipari tevékenység folyt - felméréseink szerint 68-70 km2-t foglal el Budapest közigazgatási területéből. Kutatásaink négy területre koncentrálódtak: bemutattuk az ipar mintegy 160 éves történetét, az ipari múlt örökségét (a környezeti szennyezettséget, az alacsony hatásfokú földhasználatot, a megüresedett területeket, a zavaros tulajdonviszonyokat, stb.), a korábbi funkciók spontán változásait (az új bevásárló központok, technológiai és ipari parkok megjelenését, az ipari műemlékek más célú - kulturális, lakás, stb. - felhasználását), és végül, a barnamezős területek rehabilitációjával foglalkozó, reménykeltő terveket. A barnamező megújítására irányuló erőfeszítések előtt hatalmas a kihívás. Mindazonáltal, ez a térség Budapest fejlesztésének fontos gazdasági tartaléka. | The brownfield belt of the Hungarian capital, where once large industrial production sites were located, comprises an area of 68-70 square kilometres. Our researches have been concentrated on four fields: to present the 160-year-long history of Budapest as an industrial city; the legacy of the industrial past (environmental pollution, the uneffected land use, empty areas, a messy ownership, etc.); the spontaneous changes of the former fuctions (appearence of new shopping centres, technological and industrial parks, industrial monuments used for cultural events, housing, etc.); and finally the promising plans that deal with the brownfields of Budapest. Any effort of brownfield rehabilitation in Budapest faces formidable challenges. However, this area could be promising for metropolitan development and become an important economic factor in the future

    Pelatihan Membatik Khusus untuk Anak Jalanan di Daerah Semarang, sebagai Media Positif Pengembangan Bakat

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    Sensitizing communities against street children is lacking. Though the community of street children is a component that has the same right to get all the attention and guidance. This training aims to appreciate batik to street children as a form of devotion to the community. Batik training is done with a social approach that begins with the observation that the place has a lot of street children. Alternative non-formal education suitable to be developed on street children as batik and control emotions is one of the nation\u27s preservation of culture. Results are achieved such products handkerchief, Splash batik, batik shoes, shirts / batik shirt, batik cloth, batik brands

    Thermal and catalytic decomposition studies of microalgal residue using pyrolysis-GC/MS and TG/MS

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    The marine algal biomass is one of the most promising candidates for the raw material of sustainable biofuel production. Biofuels of different phases can be converted by bio- or thermochemical methods. In this study thermogravimetry/mass spectrometry (TG/MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) were used to analyze the main decomposition products of the deoiled algal cake (DAC). Two mesoporous silica catalysts (SBA-15 and FSM-16) were applied to modify the composition of the evolving gas phase products. The yield of the evolving volatile gas products was enhanced by the use of the SBA-15. This catalyst promoted the decomposition of the inorganic carbonates into carbon dioxide. The formation of hydrocarbons during the fast pyrolysis simple alcohol molecules were formed from the deoiled algal residue. The yields of the anhydro-sugar derivatives were strongly affected by the presence of both catalysts. The intensity of the aromatic and aliphatic decomposition products were influenced by the catalytic decomposition procedure

    A differential method for bounding the ground state energy

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    For a wide class of Hamiltonians, a novel method to obtain lower and upper bounds for the lowest energy is presented. Unlike perturbative or variational techniques, this method does not involve the computation of any integral (a normalisation factor or a matrix element). It just requires the determination of the absolute minimum and maximum in the whole configuration space of the local energy associated with a normalisable trial function (the calculation of the norm is not needed). After a general introduction, the method is applied to three non-integrable systems: the asymmetric annular billiard, the many-body spinless Coulombian problem, the hydrogen atom in a constant and uniform magnetic field. Being more sensitive than the variational methods to any local perturbation of the trial function, this method can used to systematically improve the energy bounds with a local skilled analysis; an algorithm relying on this method can therefore be constructed and an explicit example for a one-dimensional problem is given.Comment: Accepted for publication in Journal of Physics

    Haptoglobin Polymorphism: A Novel Genetic Risk Factor for Celiac Disease Development and Its Clinical Manifestations

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    Background: Haptoglobin (Hp) α-chain alleles 1 and 2 account for 3 phenotypes that may influence the course of inflammatory diseases via biologically important differences in their antioxidant, scavenging, and immunomodulatory properties. Hp1-1 genotype results in the production of small dimeric, Hp2-1 linear, and Hp2-2 cyclic polymeric haptoglobin molecules. We investigated the haptoglobin polymorphism in patients with celiac disease and its possible association to the presenting symptoms. Methods: We studied 712 unrelated, biopsy-proven Hungarian celiac patients (357 children, 355 adults; severe malabsorption 32.9%, minor gastrointestinal symptoms 22.8%, iron deficiency anemia 9.4%, dermatitis herpetiformis 15.6%, silent disease 7.2%, other 12.1%) and 384 healthy subjects. We determined haptoglobin phenotypes by gel electrophoresis and assigned corresponding genotypes. Results: Hp2-1 was associated with a significant risk for celiac disease (P = 0.0006, odds ratio [OR] 1.54, 95% CI 1.20–1.98; prevalence 56.9% in patients vs 46.1% in controls). It was also overrepresented among patients with mild symptoms (69.2%) or silent disease (72.5%). Hp2-2 was less frequent in patients than in controls (P = 0.0023), but patients having this phenotype were at an increased risk for severe malabsorption (OR 2.21, 95% CI 1.60–3.07) and accounted for 45.3% of all malabsorption cases. Celiac and dermatitis herpetiformis patients showed similar haptoglobin phenotype distributions. Conclusions: The haptoglobin polymorphism is associated with susceptibility to celiac disease and its clinical presentations. The predominant genotype in the celiac population was Hp2-1, but Hp2-2 predisposed to a more severe clinical course. The phenotype-dependent effect of haptoglobin may result from the molecule’s structural and functional properties
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