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OALib Journal期刊

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The Dire Streets of Marcelino Freire's Angue de Sangue
Leila Lehnen
Hispanic Issues On Line , 2008,
Abstract:
A toxicomania e a cadeia circular das intera es familiares: a terapia familiar como teoria para a reconstru o da cidadania
Lacete Maria Lehnen
Psicologia: Ciência e Profiss?o , 1996, DOI: 10.1590/s1414-98931996000200005
Abstract:
XY models with disorder and symmetry-breaking fields in two dimensions
Stefan Scheidl,Michael Lehnen
Physics , 1998, DOI: 10.1103/PhysRevB.58.8667
Abstract: The combined effect of disorder and symmetry-breaking fields on the two-dimensional XY model is examined. The study includes disorder in the interaction among spins in the form of random phase shifts as well as disorder in the local orientation of the field. The phase diagrams are determined and the properties of the various phases and phase transitions are calculated. We use a renormalization group approach in the Coulomb gas representation of the model. Our results differ from those obtained for special cases in previous works. In particular, we find a changed topology of the phase diagram that is composed of phases with long-range order, quasi-long-range order, and short-range order. The discrepancies can be ascribed to a breakdown of the fugacity expansion in the Coulomb gas representation. Implications for physical systems such as planar Josephson junctions and the faceting of crystal surfaces are discussed.
The Influence of Body Condition on the Stopover Ecology of Least Sandpipers in the Lower Mississippi Alluvial Valley during Fall Migration
Sarah E. Lehnen,David G. Krementz
Avian Conservation and Ecology , 2007,
Abstract: Many shorebirds are long-distance migrants and depend on the energy gained at stopover sites to complete migration. Competing hypotheses have described strategies used by migrating birds; the energy-selection hypothesis predicts that shorebirds attempt to maximize energy gained at stopover sites, whereas the time-selection hypothesis predicts that shorebirds attempt to minimize time spent at stopover sites. The energy- and time-selection hypotheses both predict that birds in better condition will depart sites sooner. However, numerous studies of stopover duration have found little support for this prediction, leading to the suggestion that migrating birds operate under energy and time constraints for only a small portion of the migratory season. During fall migration 2002, we tested the prediction that birds in better condition depart stopover sites sooner by examining the relationship between stopover duration and body condition for migrating Least Sandpipers (Calidris minutilla) at three stopover sites in the Lower Mississippi Alluvial Valley. We also tested the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team that shorebirds stay in the Mississippi Valley for 10 d. The assumption of 10 d was used to estimate the amount of habitat required by shorebirds in the Mississippi Valley during fall migration; a period longer than 10 d would increase the estimate of the amount habitat required. We used multiple-day constancy models of apparent survival and program MARK to estimate stopover duration for 293 individually color-marked and resighted Least Sandpipers. We found that a four-day constancy interval and a site x quadratic time trend interaction term best modeled apparent survival. We found only weak support for body condition as a factor explaining length of stopover duration, which is consistent with findings from similar work. Stopover duration estimates were 4.1 d (95% CI = 2.8–6.1) for adult Least Sandpipers at Bald Knob National Wildlife Refuge, Arkansas, 6.5 d (95% CI = 4.9–8.7) for adult and 6.1 d (95% CI =4.2–9.1) for juvenile Least Sandpipers at Yazoo National Wildlife Refuge, Mississippi, and 6.9 d (95% CI = 5.5–8.7) for juvenile Least Sandpipers at Morgan Brake National Wildlife Refuge, Mississippi. Based on our estimates of stopover duration and the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team, there is sufficient habitat in the lower Mississippi Valley to support shorebirds during fall migration.
Enhanced spin-orbit scattering length in narrow Al_xGa_{1-x}N/GaN wires
P. Lehnen,Th. Schapers,N. Kaluza,N. Thillosen,H. Hardtdegen
Physics , 2007, DOI: 10.1103/PhysRevB.76.205307
Abstract: The magnetotransport in a set of identical parallel AlGaN/GaN quantum wire structures was investigated. The width of the wires was ranging between 1110 nm and 340 nm. For all sets of wires clear Shubnikov--de Haas oscillations are observed. We find that the electron concentration and mobility is approximately the same for all wires, confirming that the electron gas in the AlGaN/GaN heterostructure is not deteriorated by the fabrication procedure of the wire structures. For the wider quantum wires the weak antilocalization effect is clearly observed, indicating the presence of spin-orbit coupling. For narrow quantum wires with an effective electrical width below 250 nm the weak antilocalization effect is suppressed. By comparing the experimental data to a theoretical model for quasi one-dimensional structures we come to the conclusion that the spin-orbit scattering length is enhanced in narrow wires.
Aquisi??o da linguagem oral: rela??o e risco para a linguagem escrita
Fran?a, Marcio Pezzini;Wolff, Clarice Lehnen;Moojen, S?nia;Rotta, Newra Tellechea;
Arquivos de Neuro-Psiquiatria , 2004, DOI: 10.1590/S0004-282X2004000300017
Abstract: the present study relates the acquisition of oral language to the development of writing in 236 children of a private school in the city of porto alegre, brazil. the objective of this research was to identify non-linguistic factors involved in phonological acquisition and to describe the relation of phonological acquisition with alterations of writing. at the age of 6 years, kindergarten students were divided into 2 groups, based on the test of phonological evaluation of children. in the follow-up, at 9 years of age, students were evaluated by means of balanced dictation and textual production. the comparison of results from case and control groups showed statistically significant difference as to the number of mistakes made in writing, pointing to the acquisition of oral language as a predictive factor for the development of spelling.
Modelagem da ingest?o, reten??o e excre??o de nitrogênio e fósforo pela suinocultura gaúcha: interface vegetal
Lovatto, Paulo Alberto;Lehnen, Cheila Roberta;Andretta, Ines;Lovato, Gustavo Dias;Hauschild, Luciano;
Ciência Rural , 2010, DOI: 10.1590/S0103-84782010000400033
Abstract: a model was developed to simulate the nitrogen and phosphorus dynamics of pigs in the rio grande do sul state, brazil associated with corn and soybean production. the model is constituted by an animal sub-model (sma) and a vegetable one (smv). the general approaches of sma are based on technological systems (st), animal categories, n and p concentrations in diets and its digestive and metabolic efficiencies. the sma integrates three aggregation levels, constituted by ten compartments for n and p and 300 sub-compartments related to st and animal categories. the pig production data were divided in seven mesorregions in agreement with the physiographic definitions. the smv is constituted by corn and soybean sub-compartments. the smv parameters were based on the cultivated area and in the corn and soybean production of each municipal district. the simulated data show a surplus of corn and soybean in all mesorregions. annual consumption of corn and soybean meal by pigs on the state is nearly to 1.14 and 0.39 million tons, respectively. annual volume intake of n and p by the pigs is nearly 36 and 5.7 thousand tons, which 41% of n and 71% of p return to the environment. the simulated values of the different offer/demand sceneries of corn and soybean in rio grande do sul show self-sufficiency of seven mesorregions. the flows of nutrients among soil-plant-animal-soil simulated show that rio grande do sul mesorregions has levels of nitrogen and phosphorus released into the environment by the pigs below the limits imposed by the european union. the model simulates appropriately the transfers of n and p between animal and vegetable interfaces in pig production in rio grande do sul.
Porcas lactantes alimentadas com dietas contendo silagem de gr?os úmidos de milho e ácidos organicos
Lovatto, Paulo Alberto;Weschenfelder, Volnei Ant?nio;Rossi, Carlos Augusto Rigon;Lehnen, Cheila Roberta;Andretta, Ines;
Ciência Rural , 2009, DOI: 10.1590/S0103-84782009005000029
Abstract: an experiment was carried out to evaluate the performance of lactating sows and their piglets fed with high moisture corn diets with or without organic acids. fifteen sows were used in a randomized complete block with three treatments (control diet; control diet with 0.5% of benzoic acid; control diet with 0.5% of fumaric acid) with five replications each. the diets were elaborated within a 24h period. diets elaborated with high moisture corn with benzoic or fumaric acids did not modify (p>0.05) the backfat thickness and the average daily feed intake. the average daily weight gain (0.22kg) and average weaning live weight (6.2kg) of piglets were not influenced (p>0.05) between treatments. the addition of organic acids in diets containing high moisture corn does not alter the performance of lactating sows and piglets.
Metanálise da rela??o entre espessura de toicinho e variáveis corporais e reprodutivas de porcas gestantes e lactantes
Rossi, Carlos Augusto Rigon;Lovatto, Paulo Alberto;Weschenfelder, Volnei Ant?nio;Lehnen, Cheila Roberta;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000100033
Abstract: a meta-analysis was carried out to evaluate the association between backfat thickness and sow body condition in gestation and lactation. the database assembled 14 publications from 2000 to 2006. the meta-analysis was accomplished by graphical analysis, correlation, and analysis of variance. the correlation between backfat thickness (bt) and body weight was 0.16 (p<0.01), with protein mass was 0.48 (p<0.01) and leptin concentration was 0.88 (p<0.01). the correlation between the backfat variation during and in lactation (vbtl) and body weight was -0.21 (p<0.01), with body weight variation in lactation was 0.34 (p<0.01) and with fat mass variation in lactation was 0.70 (p<0.01). the correlation between bt and born alive litter size was 0.46 (p<0.01), between vbtl and piglets body weight at seven days of age was 0.95 (p<0.01). in the gestation, the bd was influenced by the body weight and protein mass. however, in lactation the vbtl was influenced by the body weight variation and fat mass. the leptin concentration at farrowing was positively correlated with backfat depth. the bt was influenced by born alive litter size and piglets birth weight. the vbtl was influenced by piglets weight at seven days old and litter weight gain. in conclusion, there is a significant relation between backfat thickness and body variables of the sows in gestation and lactation.
Rela??o entre fumonisinas na dieta de leit?es na creche e a ocorrência do vício de suc??o, desempenho e características de alguns órg?os
Lovatto, Paulo Alberto;Lehnen, Cheila Roberta;Cavazini, Neimar;Bertolin, Kalyne;Hauschild, Luciano;
Ciência Rural , 2007, DOI: 10.1590/S0103-84782007000400028
Abstract: the experiment was carried out to evaluate the effect of the suckling vice and fumonisins on the performance and characteristics of some organs of post weaning piglets. thirty-two littermates piglets where used into a factorial 2 x 2 (with and without suckling vice, with or without fumonisins in diet), with four replications and two animals for experimental unit. there was no interaction (p>0.05) between suckling vice and fumonisins for all analyzed variables. the final weight of piglets with suckling vice was 8% (p<0.05) lower than control group (25.2 x 27.5kg). suckling vice did not influence (p>0.05) the feed intake. the addition of fumonisinas in the diet reduced (p<0.05) 20% the feed intake between 22 to 28 days of experiment. the weight gain of animals fed fumonisin diets was 14% lower (p<0.05) than control group. the suckling vice got worse (p<0.05) 11% feed conversion rate (1.52 x 1.68). fumonisin diets got worse (p<0.05) 13% feed conversion rate from 15 to 21 days of experiment. the suckling vice did not modify (p>0.05) organ weights. fumonisins increased (p<0.05) the liver weight (820 x 693g) and reduced weight of heart (126 x 148g), stomach (291 x 384g), intestine (2,015 x 2,577g), pancreas (55 x 74g), and lung (291 x 350g). the suckling vice and fumonisins influence negatively the animals performance, but the vice does not modify organ weights.
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