112 resultados para Cibber, Theophilus, 1703-1758.


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The presence and biological significance of vertebrate-related steroid sex hormones in aquatic invertebrates are poorly understood. We compared the concentrations of estrogen (17β-estradiol) and testosterone between amplexing male and female freshwater amphipods of three species from two continents: Gammarus duebeni celticusLiljeborg, 1852 and G. pulex(L., 1758) from Europe, and G. pseudolimnaeusBousfield, 1958 from North America. All three species were found to have measureable concentrations of both hormones in whole body lysate samples but the concentrations differed between species, with testosterone differing significantly between species only for male amphipods and estradiol differing significantly between species only for female amphipods. Concentrations of both testosterone and estrogen differed between males and females in two of the three species ( G. duebeni celticusand G. pseudolimnaeus). Females had the highest concentration of both hormones in G. duebeni celticusand the lowest concentration of both hormones in G. pseudolimnaeus. These results contribute to a growing body of evidence that these hormones are endogenously produced and biologically relevant in amphipods. Such evidence is particularly important in light of increasing prevalence of endocrine-disrupting compounds in the environment and the central role played by amphipods in aquatic ecosystems.

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We present a fully-distributed self-healing algorithm dex that maintains a constant degree expander network in a dynamic setting. To the best of our knowledge, our algorithm provides the first efficient distributed construction of expanders—whose expansion properties holddeterministically—that works even under an all-powerful adaptive adversary that controls the dynamic changes to the network (the adversary has unlimited computational power and knowledge of the entire network state, can decide which nodes join and leave and at what time, and knows the past random choices made by the algorithm). Previous distributed expander constructions typically provide only probabilistic guarantees on the network expansion whichrapidly degrade in a dynamic setting; in particular, the expansion properties can degrade even more rapidly under adversarial insertions and deletions. Our algorithm provides efficient maintenance and incurs a low overhead per insertion/deletion by an adaptive adversary: only O(logn)O(log⁡n) rounds and O(logn)O(log⁡n) messages are needed with high probability (n is the number of nodes currently in the network). The algorithm requires only a constant number of topology changes. Moreover, our algorithm allows for an efficient implementation and maintenance of a distributed hash table on top of dex  with only a constant additional overhead. Our results are a step towards implementing efficient self-healing networks that have guaranteed properties (constant bounded degree and expansion) despite dynamic changes.

Gopal Pandurangan has been supported in part by Nanyang Technological University Grant M58110000, Singapore Ministry of Education (MOE) Academic Research Fund (AcRF) Tier 2 Grant MOE2010-T2-2-082, MOE AcRF Tier 1 Grant MOE2012-T1-001-094, and the United States-Israel Binational Science Foundation (BSF) Grant 2008348. Peter Robinson has been supported by Grant MOE2011-T2-2-042 “Fault-tolerant Communication Complexity in Wireless Networks” from the Singapore MoE AcRF-2. Work done in part while the author was at the Nanyang Technological University and at the National University of Singapore. Amitabh Trehan has been supported by the Israeli Centers of Research Excellence (I-CORE) program (Center No. 4/11). Work done in part while the author was at Hebrew University of Jerusalem and at the Technion and supported by a Technion fellowship.

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Lumpfish, or lumpsucker, Cyclopterus lumpus (Linnaeus, 1758) is widely distributed in the North Atlantic Ocean. It has a considerable economic value and substantial fisheries occur in several North Atlantic regions owing to the use of its fully ripe internal egg masses in the ovaries as an alternative to sturgeon caviar. Despite being intensively fished in several locations, biological knowledge is limited and no genetic structure information is available. In this study, the stock structure of C. lumpus was investigated across the North Atlantic using ten microsatellite loci. Out of ten loci, two exhibited higher level of differentiation but their inclusion/ exclusion from the analyses did not drastically change the observed genetic pattern. A total of three distinct genetic groups were detected: Maine-Canada-Greenland, Iceland-Norway and Baltic Sea. These results, discussed in terms of origin of differentiation, gene flow, and selection, showed that gene flow was rather limited among the detected groups, and also between Greenland and Maine-Canada.

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Lumpfish (Cyclopterus lumpus L. 1758) are widely distributed on both sides of the North Atlantic. They are a commercially important species, but stock size estimates have declined since the mid-1980s in Canada, Norway and Iceland. Little is known about the biology of this species, in particular the breeding migrations and population structure which are fundamental for effective management. This paper describes the development and characterization of twenty-two polymorphic microsatellite loci using next generation sequencing. The number of alleles per locus ranged from 3 to 27 in two geographically distant North Atlantic populations, with observed and expected heterozygosities ranging between 0. 0625-0. 979 and 0. 0618-0. 946, respectively. These loci are an important resource that will allow assessment of the population genetic structure of this species, and contribute to its appropriate management.

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The next generation sequencing revolution has enabled rapid discovery of genetic markers, however, development of fully functioning new markers still requires a long and costly process of marker validation. This study reports a rapid and economical approach for the validation and deployment of polymorphic microsatellite markers obtained from a 454 pyrosequencing library of Atlantic cod, Gadus morhua, Linnaeus 1758. Primers were designed from raw reads to amplify specific amplicon size ranges, allowing effective PCR multiplexing. Multiplexing was combined with a three-primer PCR approach using four universal tails to label amplicons with separate fluorochromes. A total of 192 primer pairs were tested, resulting in 73 polymorphic markers. Of these, 55 loci were combined in six multiplex panels each containing between six and eleven markers. Variability of the loci was assessed on G. morhua from the Celtic Sea (n 46) and the Scotian Shelf (n 46), two locations that have shown genetic differentiation in previous studies. Multilocus FST between the two samples was estimated at 0.067 (P 0.001). After three loci potentially under selection were excluded, the global FST was estimated at 0.043 (P 0.001). Our technique combines three- primer and multiplex PCR techniques, allowing simultaneous screening and validation of relatively large numbers of microsatellite loci.

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The primary enzyme involved in polyphosphate (polyP) synthesis, polyP kinase (ppk), has been deleted in Pseudomonas putida KT2440. This has resulted in a threefold to sixfold reduction in polyhydroxyalkanoate (PHA) accumulation compared with the wild type under conditions of nitrogen limitation, with either temperature or oxidative (H2O2) stress, when grown on glucose. The accumulation of PHA by Δppk mutant was the same as the wild type under nitrogen-limiting growth conditions. There was no difference in polyP levels between wild-type and Δppk strains under all growth conditions tested. In the Δppk mutant proteome, polyP kinase (PPK) was undetectable, but up-regulation of the polyp-associated proteins polyP adenosine triphosphate (ATP)/nicotinamide adenine dinucleotide (NAD) kinase (PpnK), a putative polyP adenosine monophosphate (AMP) phosphotransferase (PP_1752), and exopolyphosphatase was observed. Δppk strain exhibited significantly retarded growth with glycerol as carbon and energy source (42 h of lag period compared with 24 h in wild-type strain) but similar growth to the wild-type strain with glucose. Analysis of gene transcription revealed downregulation of glycerol kinase and the glycerol facilitator respectively. Glycerol kinase protein expression was also downregulated in the Δppk mutant. The deletion of ppk did not affect motility but reduced biofilm formation. Thus, the knockout of the ppk gene has resulted in a number of phenotypic changes to the mutant without affecting polyP accumulation.

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Much of the recent literature on youth justice has focused on administrative aspects of the system and the socio-political contexts that have led to the ‘production’ of the youthful offender as a subject and locus of intervention. This has largely been driven by the extent to which youth justice has been crafted as a distinct penal sphere, evident in its unyoking from universal children’s services (Muncie and Goldson, 2013) and the establishment of separate agencies to administer and govern this ‘system’ (Souhami, 2014). Driven by policy hyperactivity and a plethora of legislation expanding the reach of the system, for much of the 1990s and 2000s increasing numbers of young people were brought under its gaze.

Particular attention has been paid to the impact of neo-liberal governance on the discourses, rationales and philosophies underpinning contemporary youth justice policy and practice. Writing specifically in the English and Welsh context, several authors have identified that the resulting ‘system’ embodies multiple, contradictory and competing discourses (Muncie, 2006; Fergusson, 2007; Gray, 2013). Within this ‘melting pot’ Fergusson (2007) notes the disjuncture between policy rhetoric, implementation and lived experience and Phoenix (2015) argues that systems-based analyses, much in favour amongst academics, foreclose a wider consideration of questions of what ‘justice’ actually means.

Recent attention towards the perspectives of practitioners working in this sphere has pointed to greater nuances than broader penal narratives suggest (see: Field, 2007; Briggs, 2013; Gray, 2013; Kelly and Armitage, 2015). Yet similar attention has not been given to experiences of youth justice (for an exception see – Phoenix and Kelly, 2013). However, it is precisely young people’s experiences, which would add significantly to current knowledge and potentially bridge the gap between discussions about penal philosophies, how youth justice policies are framed, how they are enacted and how they are experienced.

This chapter provides an overview of recent developments in the field of youth justice and penality in the United Kingdom. The chapter argues that a theoretical focus on macro-level trends (Hannah-Moffat and Lynch, 2012), alongside a narrowly defined research agenda, have largely excluded young people’s experiences of justice and punishment from contemporary analysis. Drawing on young people experiences of different aspects of youth justice in Northern Ireland and beyond, the chapter illuminates what a close understanding of lived experience can add to knowledge. In particular it demonstrates that the effects of interventions can be different to their aims and intentions; and that re-instating the youth experience can add support to calls for greater attention to wider issues of social justice.