Effects of coastal urbanization on salt-marsh faunal assemblages in the northern Gulf of Mexico

Author Posting. © American Fisheries Society, 2014. This article is posted here by permission of American Fisheries Society for personal use, not for redistribution. The definitive version was published in Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science 6 (2014): 89-107, doi:10.1080/19425120.2014.893467.Coastal landscapes in the northern Gulf of Mexico, specifically the Mississippi coast, have undergone rapid urbanization that may impact the suitability of salt-marsh ecosystems for maintaining and regulating estuarine faunal communities. We used a landscape ecology approach to quantify the composition and configuration of salt-marsh habitats and developed surfaces at multiple spatial scales surrounding three small, first-order salt-marsh tidal creeks arrayed along a gradient of urbanization in two river-dominated estuaries. From May 3 to June 4, 2010, nekton and macroinfauna were collected weekly at all six sites. Due to the greater abundance of grass shrimp Palaemonetes spp., brown shrimp Farfantepenaeus aztecus, blue crab Callinectes sapidus, Gulf Menhaden Brevoortia patronus, and Spot Leiostomus xanthurus, tidal creeks in intact natural (IN) salt-marsh landscapes supported a nekton assemblage that was significantly different from those in partially urbanized (PU) or completely urbanized (CU) salt-marsh landscapes. However, PU landscapes still supported an abundant nekton assemblage. In addition, the results illustrated a linkage between life history traits and landscape characteristics. Resident and transient nekton species that have specific habitat requirements are more likely to be impacted in urbanized landscapes than more mobile species that are able to exploit multiple habitats. Patterns were less clear for macroinfaunal assemblages, although they were comparatively less abundant in CU salt-marsh landscapes than in either IN or PU landscapes. The low abundance or absence of several macroinfaunal taxa in CU landscapes may be viewed as an additional indicator of poor habitat quality for nekton. The observed patterns also suggested that benthic sediments in the CU salt-marsh landscapes were altered in comparison with IN or PU landscapes. The amount of developed shoreline and various metrics related to salt marsh fragmentation were important drivers of observed patterns in nekton and macroinfaunal assemblages

From Marginal Learning to Marginal Employment? The Real Impact of 'Learning' Employability Skills

This article explores notions of ‘employability’ in the context of the experiences of those young people who leave the English education system at 16+ with few or no academic credentials. The article contests the conflation of ‘employability skills’ with ‘inclusion’ in policy discourse, arguing that the real impact of such programmes is to inculcate attitudes and behaviours consistent with low-pay, low-skill work in already marginalised young people. It draws on empirical evidence from two studies which suggest that what young people really want are real, practical skills which are directly transferable to the world of work and which would fulfil the promise of high-pay, high-skill work in a knowledge economy. The article concludes that in a world where many young people are increasingly marginalised in terms of both education and employment, only an education which provides the skills the young people aspire to and which has real exchange value in the labour marketplace can confer any real advantage to them. Current approaches to employability skills education, far from achieving this, are little more than an exercise in social control resulting in new forms of class and labour (re)production, as already marginalised young people are socialised into particular forms of casual and low-pay, low-skill employment

Demography of fluctuating populations: temporal and phase-related changes in vital rates of Microtus ochrogaster

1. Small mammal population fluctuations, cyclic or not, have been an ecological puzzle and a source of heated debate among ecologists. Identifying the demographic parameters that covary closely with density changes can help elucidate the underlying causes of population fluctuations, but few studies have reported rigorous estimates of these parameters. 2. We applied capture-mark-recapture analysis to twice-weekly trapping data from a long-term study of a fluctuating Microtus ochrogaster (prairie vole) population in Illinois, USA to estimate stage-specific apparent survival and maturation rates. We also estimated population density, fecundity rate, age at maturity and life span on a weekly basis. 3. Survival, maturation and fecundity rates exhibited phase-related changes during major density fluctuations, but they showed density-independent temporal variations during the prolonged low-density phases. Among these variables, maturation and juvenile survival rates covaried most closely with population density. 4. These results suggest that phase-related changes in maturation and juvenile survival rates are likely to be the main demographic factors driving the dynamics of our study population. 5. Phase-related changes in maturation rates provide a plausible demographic explanation of density fluctuations in our study population. Our results suggest that direct predation may not be necessary for large-scale fluctuations in M. ochrogaster abundance

Large scale bioinformatics data mining with parallel genetic programming on graphics processing units

Abstract A suitable single instruction multiple data GP interpreter can achieve high (Giga GPop/second) performance on a SIMD GPU graphics card by simultaneously running multiple diverse members of the genetic programming population. SPMD dataflow parallelisation is achieved because the single interpreter treats the different GP programs as data. On a single 128 node parallel nVidia GeForce 8800 GTX GPU, the interpreter can out run a compiled approach, where data parallelisation comes only by running a single program at a time across multiple inputs. The RapidMind GPGPU Linux C++ system has been demonstrated by predicting ten year+ outcome of breast cancer from a dataset containing a million inputs. NCBI GEO GSE3494 contains hundreds of Affymetrix HG-U133A and HG-U133B GeneChip biopsies. Multiple GP runs each with a population of five million programs winnow useful variables from the chaff at more than 500 million GPops per second. Sources available via FTP.