6,115 research outputs found
Half-hypers and quivers
We study systematically the BPS spectra of N = 2 SYM coupled to half - hypermultiplets, the basic example being E7 SYM coupled to a half-hyper in the 56 irrepr. In order to do this, we determine the BPS quivers with superpotential of such N = 2 models using a new technique we introduce. The computation of the BPS spectra in the various chambers is then reduced to the Representation Theory of the resulting quivers. We use the quiver description to study the BPS spectrum at both strong and weak coupling. The following models are discussed in detail: SU(6) SYM coupled to a 1/2 20, SO(12) SYM coupled to a 1/2 32, and E7 SYM coupled to a 1/2 56. For models with gauge group SU(2) × SO(2n) and matter in the 1/2 (2, 2n) we find strongly coupled chambers with a BPS spectrum consisting of just finitely many hypermultiplets. © SISSA 2012
Suppression of lift-up effect in the 3D Boussinesq equations around a stably stratified Couette flow
A new species of Turbanellidae (Gastrotricha, Macrodasyida) from Jamaica, with a key to species of Paraturbanella
The study falls within the framework of a wider research programme aimed at investigating the gastrotrich
diversity of the Tropical North-Western Atlantic (TNWA). A new macrodasyidan gastrotrich is described
from fine-medium sand collected at Duncans Bay, Jamaica. The description is based on observations carried
out on living specimens using differential interference contrast microscopy. Paraturbanella xaymacana
sp. n., the third gastrotrich taxon reported from Jamaica, is a mid-sized species, up to 564 \u3bcm long, with
a feeble peribuccal swelling. The most obvious autapomorphic traits pertain to the testes and the male
pore, both of which are located approximately at mid body, rather than at- or near the pharyngo-intestinal
junction as occur in the other species of the genus. Additional differences with congeners are discussed and
a key to the Paraturbanella species is provided, in the hope it will be useful to both gastrotrich experts and
marine ecologists who discover these microscopic metazoans during their research
First records of Gastrotricha from South Africa, with description of a new species of Halichaetonotus (Chaetonotida, Chaetonotidae)
During a survey of the biota of the St. Lucia Estuary in the iSimangaliso Wetland Park, South Africa, a number of Gastrotricha were found among samples of meiofauna. Fresh, marine sediment yielded several specimens belonging to a total of seven species. Of these, two are already known from other regions (i.e., Dactylopodola australiensis and Heteroxenotrichula squamosa), one is described as new to science (Halichaetonotussanctaeluciae sp. n.), while the remaining four (Pseudostomella sp., Halichaetonotus sp.1, Halichaetonotus sp. 2, Xenotrichula sp.) require further collections and analysis, in order to establish the extent of their affiliation to species already described. General appearance, shape of hydrofoil scale and the occurrenceof three long spines on the dorsal side make the new species most closely related to H. australis and H. marivagus. The key differences from these taxa and between Halichaetonotus sanctaeluciae sp. n. and H. aculifer are discussed
Assessment of Natural Resources Use for Sustainable Development - DPSIR Framework for Case Studies in Portsmouth and Thames Gateway, U.K.
This chapter reports on the uses of the DPSIR framework to assess the sustainability of the intertidal environments within the two UK case study areas, Portsmouth and Thames Gateway. It focuses on statutory conservation areas dominated by intertidal habitats. Two are located in Portsmouth (Portsmouth and Langstone Harbours) and four in the Thames Gateway (Benfleet Marshes, South Thames Estuary, Medway Estuary and the Swale in the Thames Gateway). Based on the reduction of a number of pressures and impacts observed in recent decades and the improvement of overall environmental quality, all six SSSIs are considered to be sustainable in the short and medium term. In the future, it is possible that the impacts of climate change, especially sea-level rise, might result in further reduction in the area and/or quality of intertidal habitats. Further integration between conservation and planning objectives (both for urban development and management of flood risk) at local level is needed to support the long-term sustainability of intertidal habitats
GENETIC AND PRODUCTIVE CHARACTERIZATION OF THE BURLINA CATTLE BREED
The Burlina (BUR) is a local Italian cattle breed, its main feature is to be a small sized animal well adapted to live in difficult environment such as mountain areas. Nowadays only 350 cows are enrolled in the Italian Herd Book due to its substitution by more productive breeds. This study proposes a phenotypic and genetic characterization of the BUR breed in comparison with Holstein Friesian (HFR) and Brown Swiss (BSW). The comparison of productive traits showed lower production than HFR and BSW as well as longer productive life and more favourable reproductive traits in BUR animals. The genetic analyses, performed by microsatellites markers, showed the high level of heterozygosity and the genetic distinctiveness of BUR. These findings approve the feasibility of a conservation scheme and suggest the profitability of breeding BUR, especially in difficult environment where the low production can be compensated by longevity and the economic loss by the added value of its typical dairy production
Density Estimates and Habitat Preferences of Two Sympatric Bird Species as Potential Bioindicators of Tropical Forest Alterations
Forestry management can shape the structure of habitat types and have important biological consequences on the composition of biodiversity. This study focused on Momotus lessonii and Eumomota superciliosa, two potential bioindicators of local and wide scale tropical forest alterations. The study took place in the Karen Mogensen Wildlife Refuge (Costa Rica), a protected area characterized by two main forest habitats where the two species coexist, i.e., primary moist and second-growth dry forest. A distance sampling method was used to obtain density estimates for each species. A spot mapping approach showed an apparent partitioning of the two species at the site. The Kilometric Abundance Index (KAI) and statistical analyses revealed significant differences between the two habitats, i.e., E. superciliosa tended to be more abundant and preferred the dry forest, whilst M. lessonii favored moist environments. The development of arid and semi-arid environments characterized by open areas will probably lead to a numerical increase in E. superciliosa with a consequent expansion, while the decline of moister and homogeneously forested environments will likely affect negatively M. lessonii. We argue that these birds will act as bioindicators of local and global environmental changes, and their monitoring will enable appropriate forest management decisions for conservation purposes
GENETIC CHARACTERISATION OF ITALIAN CHICKEN BREEDS USING A PANEL OF TWENTY MICROSATELLITE MARKERS
Genetic relationships among four Veneto native breeds of chickens were studied on the basis of microsatellites polymorphisms. A total of 190 DNA samples (45 Robusta Lionata, 43 Robusta Maculata, 45 Ermellinata di Rovigo, 45 Pèpoi) and a commercial broiler line (12 Golden Comet) were genotyped at 20 microsatellite loci. The average number of alleles per locus was 5 and the expected heterozygosity resulted lower for the local breeds than for the commercial broiler line used as reference. The inbreeding coefficient showed a deficit of heterozygotes, highest for the Robusta Lionata breed. Nei’s standard genetic distances corrected for bias due to sampling of individuals (Da), based on allele frequencies, and Reynolds distances (DReynolds) were calculated among breeds. The Robusta Lionata and Robusta Maculata resulted very similar approving the same genetic origin. A Neighbor-Joining tree drawn from DReynolds distances clustered three groups, one including the Robusta Lionata and Robusta Maculata breeds, the second one formed by the Ermellinata di Rovigo and the Golden Comet commercial line and the third by the Pèpoi. The results showed the genetic differences occurring between the local chicken breeds
Effect of crossbreeding on milk yield traits and somatic cell score in dairy cattle
This study aimed to estimate trends of heterosis for milk yield traits and somatic cell score (SCS) in the Dutch dairy cattle. First lactation data on 305-d milk, fat, and protein yield, and on average 305-d SCS recorded on pure Holstein Friesian (HF), Dutch Friesian (DF), Mosa Reno Yssel (MRY), and F1 crossbreds (DFxHF and MRYxHF) were considered. According to cows' year of calving, productive records from animals calving from 1980 to 2004 were divided in five periods, while SCS records from animals calving from 1990 to 2004 were divided in four periods. Data were processed using analysis of variance (ANOVA) according to a linear model which included effects of herd, season of calving, age at calving, and the genotype by period of calving interaction effect. Moreover, a linear covariate of sire's estimated breeding value (EBV) for 305-d milk yield was added to the model for yield traits. Heterosis values for productive traits were positive but decreased over time. For 305-d milk yield these values changed from 7.5 to 3.0% in the DFxHF crossbreds, and from 9.0 to 1.0% in the MRYxHF crossbreds. Average heterosis for SCS (-1.2%) was small and negative with a favourable trend over years
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