2,189 research outputs found
A comparison, by sweep sampling, of the arthropod fauna of secondary vegetation in Michigan, England and Costa Rica
1.  Six 800-sweep samples of English and Michigan (“old field”) secondary vegetation arthropods are compared with Costa Rican samples taken in the same way. 2.  Parasitic Hymenoptera and spiders accounted for a larger proportion of the arthropod fauna in the mid-latitude than the tropical samples. 3.  In one English field, the seasonal change in insect numbers was 88% of that recorded over all the seasonal and elevational changes examined in Costa Rica. Furthermore, the difference in the total dry weights of the arthropod fauna between December and July was similar to the difference found between the wet and dry seasons in tropical secondary vegetation (also similar to the difference between day and night values during the dry season). 4.  Aphids and Psyllidae were far more abundant in the English site than in the Costa Rican mainland sites. 5.  In mid-summer, the English field had far more arthropods in it than did any of the tropical sites sampled.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73688/1/j.1365-2311.1975.tb00551.x.pd
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Multiple paternity, sperm storage, and reproductive success of female and male painted turtles (Chrysemys picta) in nature
When females receive no direct benefits from multiple matings, concurrent multiple paternity is often explained by indirect genetic benefits to offspring. To examine such possibilities, we analyzed genetic paternity for 1,272 hatchlings, representing 227 clutches, from a nesting population of painted turtles (Chrysemys picta) on the Mississippi River. Goals were to quantify the incidence and distribution of concurrent multiple paternity across clutches, examine temporal patterns of sperm storage by females, and deduce the extent to which indirect benefits result from polyandrous female behaviors. Blood samples from adult males also allowed us to genetically identify the sires of surveyed clutches and to assess phenotypic variation associated with male fitness. From the genetic data, female and male reproductive success were deduced and then interpreted together with field data to evaluate possible effects of female mating behaviors and sire identity on offspring fitness. We document that more than 30% of the clutches were likely fathered by multiple males, and that presence of multiple paternity was positively correlated with clutch size. Furthermore, the data indicate that the second male to mate typically had high paternity precedence over the first
Varkenshouderij in niet-concentratiegebieden : op weg naar duurzaamheid
In opdracht van de vakgroepen varkenshouderij van de N LTO en WLTO is onderzoek uitgevoerd naar de voorwaarden om een duurzame varkenshouderij in de niet-concentratiegebieden mogelijk te maken. Met behulp van gegevens uit de CBS-Landbouwtelling, een analyse van de inhoud van Streek- en Bestemmingsplannen en de resultaten van een enquĂŞte onder varkenshouders is nagegaan op welke wijze gekomen kan worden tot: 1) een verantwoorde en duurzame afzet van de geproduceerde mest; 2) een optimale afstemming tussen opfokzeugen, zeugen en vleesvarkens in het gebied; 3) ontwikkelingsmogelijkheden voor individuele bedrijven. Hiervoor zijn oplossingsrichtingen aangegeven en worden beleidsaanbevelingen gedaa
The phase diagram of L\'evy spin glasses
We study the L\'evy spin-glass model with the replica and the cavity method.
In this model each spin interacts through a finite number of strong bonds and
an infinite number of weak bonds. This hybrid behaviour of L\'evy spin glasses
becomes transparent in our solution: the local field contains a part
propagating along a backbone of strong bonds and a Gaussian noise term due to
weak bonds. Our method allows to determine the complete replica symmetric phase
diagram, the replica symmetry breaking line and the entropy. The results are
compared with simulations and previous calculations using a Gaussian ansatz for
the distribution of fields.Comment: 20 pages, 7 figure
Stability of the replica-symmetric saddle-point in general mean-field spin-glass models
Within the replica approach to mean-field spin-glasses the transition from
ergodic high-temperature behaviour to the glassy low-temperature phase is
marked by the instability of the replica-symmetric saddle-point. For general
spin-glass models with non-Gaussian field distributions the corresponding
Hessian is a matrix with the number of replicas tending to
zero eventually. We block-diagonalize this Hessian matrix using representation
theory of the permutation group and identify the blocks related to the
spin-glass susceptibility. Performing the limit within these blocks we
derive expressions for the de~Almeida-Thouless line of general spin-glass
models. Specifying these expressions to the cases of the
Sherrington-Kirkpatrick, Viana-Bray, and the L\'evy spin glass respectively we
obtain results in agreement with previous findings using the cavity approach
Effects of vegetation density on flow, mass exchange and sediment transport in lateral cavities
Large-Eddy Simulations (LES) were used to investigate the hydrodynamics and mass transfer between the flow in the main channel and a vegetated lateral cavity. Fourteen vegetation densities (0 to 10.65 %) were tested, revealing two distinct hydrodynamic patterns. For cavities with low vegetation density (a 3.99 %), two gyres in contact with the interface with low velocity were formed, the thickness of the mixing layer did not grow, and the vorticity and turbulence kinetic energy were low inside the cavity. The mass transport presented the same threshold value as the hydrodynamics (a = 3.99 %). For cavities with low vegetation density, a fast mass transfer occurred through the interface between the main channel and cavity and inside the cavity, while the opposite was observed for cavities with high vegetation density. Finally, the modelled hydrodynamics was used to infer possible sediment deposition patterns and flow resistance
Navigating and querying code without getting lost
A development task related to a crosscutting concern is chal-lenging because a developer can easily get lost when explor-ing scattered elements of code and the complex tangle of re-lationships between them. In this paper we present a source browsing tool that improves the developer’s ability to work with crosscutting concerns by providing better support for exploring code. Our tool helps the developer to remain ori-ented while exploring and navigating across a code base. The cognitive burden placed on a developer is reduced by avoiding disorienting view switches and by providing an ex-plicit representation of the exploration process in terms of exploration paths. 1
História, cultura, gênero e poder: representações sociais em movimento no seriado de TV Homeland (2001-2013)
In contrast to Muslins traditions and costumes, the US government and society seems to invest
in the media to forge discourses on Western way of life. In addition, it creates idealized images
of the woman, the hero, the father, the family, and an everyday speech invoking repeated and
widespread moral values, including “justice” and “freedom”, in opposition to the “terror”. In
this research we analysed the TV series Homeland, using as theoretical support the Cultural
Studies, particularly the concept of Social Representation by Denise Jodelet, the analytics tools
created by Michel Foucault on power devices, and feminist studies by Teresa of Lauretis. I’ve
tried to see how forces in correlations operate, and how representations of womanhood,
sexuality and nationality are built and reiterated in speeches, creating patterns of behaviour for
men and women. Spreading images of the “good” man, the “good” wife, and the “hero”, the
audio-visual product creates and produces the family, the society and the nation considered
exemplar.Coordenação de Aperfeiçoamento de Pessoal de NĂvel SuperiorDissertação (Mestrado)Em contraste com os costumes de povos de tradição mulçumana, o governo estadunidense
parece investir em articulações na mĂdia para forjar o modelo idealizado de vida Ocidental e,
nesse esforço, cria tambĂ©m as imagens da “mulher”, do herĂłi, do pai, da famĂlia, e todo um
discurso cotidiano que invoca valores morais reiterados e disseminados, inclusive de “justiça”
e “liberdade”, em contraposição a uma imagem do “terror”. Essa pesquisa teve por objetivo a
análise da série de TV Homeland, utilizando como suporte teórico os estudos culturais,
particularmente o conceito de Representações Sociais de Denise Jodelet, de poder e seus
dispositivos, de Michel Foucault, e os estudos de feministas e de gênero, e as reflexões de
Teresa de Lauretis. Observo como as correlações de forças operam e como as representações
do feminino, da sexualidade e imagens do herói, - o “bom” homem, a “boa” esposa etc. - e da
nação sĂŁo construĂdas e reiteradas nos discursos, modelando homens e mulheres, pautando
condutas e insinuando o comportamento socialmente desejável ou “correto” de sujeitos e/ou
assujeitados, na produção da famĂlia, da sociedade ou da nação considerada exemplar
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