844 research outputs found
Asymptotically Safe Standard Model via Vector-Like Fermions
We construct asymptotically safe extensions of the Standard Model by adding
gauged vector-like fermions. Using large number-of-flavour techniques we argue
that all gauge couplings, including the hypercharge and, under certain
conditions, the Higgs coupling can achieve an interacting ultraviolet fixed
point.Comment: 5 pages, 3 figures, typos fixe
Exploring the Strategic Alignment of Performing Arts and Computing: Creating and Delivering Multimedia Performing Arts Content, Part II
Our Exploring the Strategic Alignment of Performing Arts and Computing initiative aims to develop an interdisciplinary Seidenberg-Performing arts curriculum that will integrate into the performing arts program an expansion of exposure to information technology skills and expertise relevant to creating and delivering computer mediated content. During spring and fall terms 2010 we successfully launched the interdisciplinary course Creating with Web 2.0.
The fall 2010 offering includes majors from Finance, Marketing, Accounting, Computer Science, Information Systems and Performing Arts. The first offering enrolled 13 students from Marketing, Finance, Information Systems, Computer Science, Communications and Film.
During spring and fall 2011 we will further develop the initial course by creating and including more sophisticated Performing to create content and to focus more attention towards recruiting Performing Arts majors.
The concept of creating interactive content as an interdisciplinary curriculum offering has been shown to succeed through our first two offerings of the course. In this segment of the project we will focus much more on Performing Arts individuals and creating more sophisticated content during the Performing Arts classes, and then integrating this content into a living web presence for the Performing Artists and for students from other majors who may also enter the class
Spatio-temporal patterns of fish assemblages in a large regulated alluvial river
1. The River Durance, the last alpine tributary of the River Rhone, is a large, braided alluvial hydrosystem. Following large-scale regulation, flow downstream of the Serre-Poncon dam has been maintained at 1⁄40th of previous annual mean discharge. To assess the effects of historical disturbances, fish assemblages and habitat use were analysed during five summers in a representative reach of the middle Durance. 2. Habitat availability and use were assessed with a multi-scale approach including the variables water depth, current velocity, roughness height of substratum, amount of woody debris and lateral⁄longitudinal location. Eighteen fish species were sampled by electrofishing in 289 habitat sample units. 3. Partial least square (PLS) regression showed that taxa were mainly distributed according to relationships between their total length and water depth⁄velocity variables. Fish assemblage composition was also related to roughness height as well as distance from the bank or to the nearest large woody debris. However, PLS regression revealed no significant differences in habitat selection between two periods of varying hydromorphological stability. 4. Fish distribution patterns and density were related to proximity to the bank and cover, indicating that local scale variables need to be considered in conservation and restoration programmes
Predation risk and abiotic habitat parameters affect personality traits in extremophile populations of a neotropical fish (<i style="box-sizing: border-box;">Poecilia vivipara</i>)
Understanding whether and how ambient ecological conditions affect the distribution of personality types within and among populations lies at the heart of research on animal personality. Several studies have focussed on only one agent of divergent selection (or driver of plastic changes in behavior), considering either predation risk or a single abiotic ecological factor. Here, we investigated how an array of abiotic and biotic environmental factors simultaneously shape population differences in boldness, activity in an open‐field test, and sociability/shoaling in the livebearing fish Poecilia vivipara from six ecologically different lagoons in southeastern Brazil. We evaluated the relative contributions of variation in predation risk, water transparency/visibility, salinity (ranging from oligo‐ to hypersaline), and dissolved oxygen. We also investigated the role played by environmental factors for the emergence, strength, and direction of behavioral correlations. Water transparency explained most of the behavioral variation, whereby fish from lagoons with low water transparency were significantly shyer, less active, and shoaled less than fish living under clear water conditions. When we tested additional wild‐caught fish from the same lagoons after acclimating them to homogeneous laboratory conditions, population differences were largely absent, pointing toward behavioral plasticity as a mechanism underlying the observed behavioral differences. Furthermore, we found correlations between personality traits (behavioral syndromes) to vary substantially in strength and direction among populations, with no obvious associations with ecological factors (including predation risk). Altogether, our results suggest that various habitat parameters simultaneously shape the distribution of personality types, with abiotic factors playing a vital (as yet underestimated) role. Furthermore, while predation is often thought to lead to the emergence of behavioral syndromes, our data do not support this assumption
From little things, big things grow: trends and fads in 110 years of Australian ornithology
Publishing histories can reveal changes in ornithological effort, focus or direction through time. This study presents a bibliometric content analysis of Emu (1901–2011) which revealed 115 trends (long-term changes in publication over time) and 18 fads (temporary increases in publication activity) from the classification of 9,039 articles using 128 codes organised into eight categories (author gender, author affiliation, article type, subject, main focus, main method, geographical scale and geographical location). Across 110 years, private authorship declined, while publications involving universities and multiple institutions increased; from 1960, female authorship increased. Over time, question-driven studies and incidental observations increased and decreased in frequency, respectively. Single species and ‘taxonomic group’ subjects increased while studies of birds at specific places decreased. The focus of articles shifted from species distribution and activities of the host organisation to breeding, foraging and other biological/ecological topics. Site- and Australian-continental-scales slightly decreased over time; non-Australian studies increased from the 1970s. A wide variety of fads occurred (e.g. articles on bird distribution, 1942–1951, and using museum specimens, 1906–1913) though the occurrence of fads decreased over time. Changes over time are correlated with technological, theoretical, social and institutional changes, and suggest ornithological priorities, like those of other scientific disciplines, are temporally labil
Effect of mid-line or low-line milking systems on lipolysis and milk composition in dairy goats
[EN] Two experiments were carried out to investigate how milking in mid-line (ML) affects the lipolysis level and milk composition in goat livestock, in comparison with low-line (LL) milking. The first experiment took place, in triplicate, on an experimental farm. For each replicate, a crossover design (62 goats, two treatments, ML and LL, in two periods each lasting 4 days) was used. Milk samples were taken daily at 0 and 24 h after milking. In the first experimental replicate, some enzymatic coagulation cheeses were made, which were assessed by a panel of tasters at 50 and 100 days of maturation. In the second experiment, the lipolysis level and composition of tank milk from 55 commercial dairy goat farms (25 ML and 30 LL) were analysed, in milk samples taken in three different weeks. The results of the first experiment showed that ML milking increased free fatty acid (FFA) concentration in raw goat's milk significantly (0.71 v. 0.40 mmol/l, respectively). However, in the milk samples taken from commercial farms the FFA concentration remained unaffected by the milking pipeline height (0.59 v. 0.58 mmol/l for ML and LL, respectively). No significant differences were found in the milk composition, nor in the sensory characteristics in the cured cheeses, which suggests that factors other than the milkline height are able to influence the level of lipolysis under commercial conditions. Therefore, ML milking should not be discouraged, provided that the correct functioning and management of the milking operation and milk storage on the farm is guaranteed.Beltrán Martínez, MC.; Manzur Cruz, A.; Rodríguez Garcia, M.; Díaz Sánchez, JR.; Peris Ribera, CJ. (2018). Effect of mid-line or low-line milking systems on lipolysis and milk composition in dairy goats. Journal of Agricultural Science. 156(8):848-854. https://doi.org/10.1017/S0021859618000771S848854156
The conditional benefits of cannibalism for wood frog tadpoles (lithobates sylvaticus)
Wood frog tadpoles have an incredible ability to rapidly adapt to changing conditions, and when population densities become high tadpoles often become cannibalistic. Cannibalism potentially represents an ideal diet by composition, and should be beneficial to the growth and development of cannibalistic individuals. To test the relative efficacy of cannibalism to growth and development we conducted multiple feeding experiments. Results indicate that cannibalism represents a better alternative to starvation and provides some benefit to development and survival of tadpoles over low quality diets. However, cannibalism can be detrimental to tadpole growth and/or development relative to diets of similar protein content. Additionally, tadpoles raised individually appear to initially avoid consuming the cannibalistic diet, and may continue to do so until they face the risk of starvation. Conversely, when tadpoles were raised in groups providing them with competition, they immediately fed upon the cannibal diet. Our results suggest that competition, rather than dietary quality is likely the driving force behind cannibalistic behaviour unless tadpoles otherwise face the risk of starvation
Can translocated native fishes retain their trophic niche when confronted with a resident invasive?
Diet interactions between native and non-native fishes may influence the establishment of native species within their historical range (i.e., reintroduction). Therefore, we illustrated the food web structure of and followed the transition of the federally endangered humpback chub Gila cypha into a novel food web following translocation and determined the potential for a non-native species, rainbow trout Oncorhynchus mykiss, to influence translocation success. Humpback chub and rainbow trout used resources high in the food web and assimilated similar proportions of native fishes, suggesting non-native rainbow trout may occupy an ecological role similar to humpback chub. Subsequently, humpback chub may be well suited to colonise tributaries because of their ability to consume resources high in the food web. Additionally, diet partitioning may occur between all members of the fish community as indicated by separation in trophic niche space and little trophic overlap; although all species, particularly bluehead sucker Catostomus discobolus, used a broad range of food resources. Rainbow trout stomach content analysis corroborated stable isotope analysis and suggested rainbow trout diet consisted of aquatic and terrestrial macroinvertebrates, while larger rainbow trout (\u3e120 mm total length) consumed a greater proportion of fish (incidence of piscivory = 5.3%). Trophic interactions may reveal an underutilized niche space or biotic resistance to the establishment of translocated native fishes. Continued translocation of humpback chub into tributaries appears to be one option for conservation. However, successful establishment of humpback chub may depend on continued removal of non-native trout, increasing availability of diet sources at higher trophic levels
Adaptation as a potential response to sea-level rise: a genetic basis for salinity tolerance in populations of a coastal marsh fish
Relative sea-level rise is resulting in the intrusion of saline waters into marshes historically dominated by fresh water. Saltwater intrusions can potentially affect resident marsh species, especially when storm-related tidal surges cause rapid changes in salinity. We examined the role of historical salinity exposure on the survival of Gambusia affinis from two locations in coastal Louisiana. At each location, we sampled fish populations from fresh, intermediate and brackish marshes. Individuals were then exposed to a salinity of 25‰ and survival time was measured. We found that fish from brackish and intermediate marshes had an increased tolerance to salinity stress relative to fish from freshwater environments. We then tested the descendents of fish from the fresh and brackish marshes, reared for two generation in fresh water, to determine if there was a genetic basis for differential survival. We found that descendents of individuals from brackish marshes showed elevated survivals relative to the descendents of fish with no historical exposure to salinity. The most reasonable mechanism to account for the differences in survival relative to historical exposure is genetic adaptation, suggesting that natural selection may play a role in the responses of resident marsh fishes to future increases in salinity
SOLIS PRAIA HOTEL ITAPEMA: os desafios na contratação de mão de obra
O Solis Praia Hotel Itapema, localizado na região central da cidade de Itapema, conta com aproximadamente 6.000 m2 de área construída, 85 apartamentos e total estrutura física e administrativa, para um estabelecimento de categoria superior. Situado no litoral Norte Catarinense, sofre com o problema da falta de mão de obra em determinadas épocas do ano, por estar numa região turística de alta sazonalidade. Junto com esta temática, outros fatores como a alta rotatividade no setor, a concorrência com outros estabelecimentos de serviços e a falta de capacitação também contribuem para agravar esta situação. A contratação temporária de um grande número de funcionários torna difícil a manutenção de um padrão de qualidade no atendimento ao hóspede, tendo em vista esta falta capacitação da mão de obra e o pouco tempo para ambientação e treinamento destas pessoas. Contudo o objetivo principal deste estudo é analisar estes fatores, verificando como cada um deles interfere no produto Solis, permitindo ao hotel atrair pessoas comprometidas, incentivar aqueles que lá estão e, assim, garantir a sua permanência neste mercado competitivo
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