1,388 research outputs found

    Seasonal variation in food preference and feeding ecology of two juvenile marine fishes, Pseudotolithus senegalensis (Sciaenidae) and Brachydeuterus auritus (Haemulidae) off Cape Coast, Ghana

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    Aspects of the feeding habits and diet of juveniles of the cassava croaker Pseudotolithus senegalensis (Valenciennes, 1833) (Sciaenidae) and bigeye grunt Brachydeuterus auritus (Valenciennes, 1831) (Haemulidae) in the inshore waters of Cape Coast, Ghana are reported in the study. Both species had a similar diet consisting of larvae of fish, shrimps and cuttlefish. The croaker ingested prey up to 77% of its total length while the bigeye grunt consumed prey up to 70% of its total length. Analysis of the stomach contents, based on the frequency of occurrence, and numerical and gravimetric compositions of these food items indicated that shrimps were the main food of P. senegalensis while B. auritus fed mainly on fish. While shrimps constituted the predominant food of the croakers all-year-round, the bigeye grunts appeared to shift their preference for fish to shrimps from June to September. The results of the study are compared with those on croakers from other parts of the Gulf of Guinea. The study, however, appears to be the first to give a detailed account of the food preference and feeding ecology of the bigeye grunt

    The consequences of executive turnover

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    The high rate of executive turnover in the healthcare industry is a major issue for health service organisations and their staff both in Australia and internationally. In the course of planning a research project examining nurse turnover at the clinical level within three Australian States/Territories, the researchers became aware of frequent executive turnover at all levels (State Department of Health, Area Health Service, hospital). Over a period of approximately 2 years there were 41 executives occupying 18 different positions, highlighting the scope of this issue in Australia. Few studies have examined the causes and consequences of this phenomenon in depth. Factors such as age, gender, education, lack of career advancement opportunities and remuneration have all been identified in the literature as important contributors to executive turnover. High turnover rates have been found to be associated with a number of negative consequences, including organisational instability, high financial costs, loss of human capital and adverse effects on staff morale and patient care. While the use of 'acting' roles may assist in filling executive positions on a temporary basis, consequences for the rest of the organisation are associated with their extended use. Steps which health services planners may take to attempt to minimise executive turnover include providing staff members with appropriate challenges and opportunities for growth and ensuring that a clear succession plan is in place to minimise the impact for the organisation and its staff. © The Author(s) 2011

    SSR-Based Genetic Structure Study of Seventy-Eight Cowpea (Vigna unguiculata (L.) Walp) Genotypes

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    Seventy-eight cowpea accessions were studied using short sequence repeats (SSR) technique. Genetic structure of these accessions was studied using three SSR polymorphic primers, SSR-6206, SSR-6218 and SSR-6219. A total of eight loci were scored for the three primers with a total of ten alleles. Bayesian clustering method grouped the cowpea genotypes into 4 sub-populations. Ancestral allele frequencies ranged between 0.128 and 0.802, while allele frequencies within sub-populations ranged from 0.001 and 0.997. Allele frequency divergence among sub-populations ranged from 0.145 to 0.406. Expected heterozygosity between individuals in the same sub-population ranged from 0.084 and 0.26, Mean genetic differentiation among sub-populations ranged from 0.374 and 0.687, with a mean geneflow ranging from 0.228 and 0.837. There was relative uniformity within the sub-populations which can be accounted for by independent random genetic drift

    Airports at Risk: The Impact of Information Sources on Security Decisions

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    Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport employees in European Airports across the continent, we analyzed how both formal and informal sources of security information affect employee's decisions to comply with the security rules and directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels

    Marker Assisted Foreground Selection for Identification of Striga Resistant Backcross Lines in Sorghum bicolor

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    Striga is a major constraint to sorghum production causing high yield loss due to increasing infestation. Locally-adapted cultivars with resistant genes/QTLs could be an effective control strategy for Striga. Marker-Assisted Foreground Selection was used to select backcross lines possessing Striga resistance QTLs from N13. Marker polymorphism was conducted for the donor parent N13 and 10 recurrent parents using 10 Simple Sequence Repeat (SSR) markers. Recurrent parents with SSR alleles, polymorphic to the donor parent allele were selected. F1 lines were developed by making a cross between the selected recurrent parent and the donor. The F1 were confirmed for heterozygosity using SSR markers. Selected heterozygote F1s were backcrossed to their recurrent parent to develop backcross populations (BC1F1 and BC2F1). BC1F1 and BC2F1 populations were genotyped using SSR markers flanking the Striga resistant QTLs in N13. Forty two DANYANA-N13 BC2F1 lines (with 4 QTLs in 3 lines, 3 QTLs in 10 lines and other 28 lines having 1 to 2 QTLs) were selected for the presence of N13 QTLs. Forty three SAMSORG39-N13 BC2F1 lines (with 3 QTLs in 2 lines while 41 lines had 1 to 2 QTLs) were also selected for the presence of N13 QTLs. Although, selected lines will be genotyped for the recovery of recurrent parent background and evaluated to identify elite genotypes for possible release as varieties, the successful introgression of Striga resistance QTLs using Marker Assisted Selection suggests that in developing superior sorghum varieties, breeders could make use of molecular marker technologies to speed up breeding programmes

    The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

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    The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained during this event, that we combine with 58 spectra gathered during the fainter December 2015 sequel outburst, as well as with 57 spectra from the 1989 event. We previously reported the discovery of wind-related features (P-Cygni and broad-wing line profiles) during both 2015 outbursts. Here, we build diagnostic diagrams that enable us to study the evolution of typical emission line parameters, such as line fluxes and equivalent widths, and develop a technique to systematically detect outflow signatures. We find that these are present throughout the outburst, even at very low optical fluxes, and that both types of outflow features are observed simultaneously in some spectra, confirming the idea of a common origin. We also show that the nebular phases depict loop patterns in many diagnostic diagrams, while P-Cygni profiles are highly variable on time-scales of minutes. The comparison between the three outbursts reveals that the spectra obtained during June and December 2015 share many similarities, while those from 1989 exhibit narrower emission lines and lower wind terminal velocities. The diagnostic diagrams presented in this work have been produced using standard measurement techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages appendix with extra tables and figures. 18 figures are included in the paper and 8 in the appendi

    Marker Assisted Foreground Selection for Identification of Striga Resistant Backcross Lines in Sorghum bicolor

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    Striga is a major constraint to sorghum production causing high yield loss due to increasing infestation. Locally-adapted cultivars with resistant genes/QTLs could be an effective control strategy for Striga. Marker-Assisted Foreground Selection was used to select backcross lines possessing Striga resistance QTLs from N13. Marker polymorphism was conducted for the donor parent N13 and 10 recurrent parents using 10 Simple Sequence Repeat (SSR) markers. Recurrent parents with SSR alleles, polymorphic to the donor parent allele were selected. F1 lines were developed by making a cross between the selected recurrent parent and the donor. The F1 were confirmed for heterozygosity using SSR markers. Selected heterozygote F1s were backcrossed to their recurrent parent to develop backcross populations (BC1F1 and BC2F1). BC1F1 and BC2F1 populations were genotyped using SSR markers flanking the Striga resistant QTLs in N13. Forty two DANYANA-N13 BC2F1 lines (with 4 QTLs in 3 lines, 3 QTLs in 10 lines and other 28 lines having 1 to 2 QTLs) were selected for the presence of N13 QTLs. Forty three SAMSORG39-N13 BC2F1 lines (with 3 QTLs in 2 lines while 41 lines had 1 to 2 QTLs) were also selected for the presence of N13 QTLs. Although, selected lines will be genotyped for the recovery of recurrent parent background and evaluated to identify elite genotypes for possible release as varieties, the successful introgression of Striga resistance QTLs using Marker Assisted Selection suggests that in developing superior sorghum varieties, breeders could make use of molecular marker technologies to speed up breeding programmes

    INTEGRAL long-term monitoring of the Supergiant Fast X-ray Transient XTE J1739-302

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    In the past few years, a new class of High Mass X-Ray Binaries (HMXRB) has been claimed to exist, the Supergiant Fast X-ray Transients (SFXT). These are X-ray binary systems with a compact companion orbiting a supergiant star which show very short and bright outbursts in a series of activity periods overimposed on longer quiescent periods. Only very recently the first attempts to model the behaviour of these sources have been published, some of them within the framework of accretion from clumpy stellar winds.Our goal is to analyze the properties of XTE J1739-302/IGR J17391-3021 within the context of the clumpy structure of the supergiant wind. We have used INTEGRAL and RXTE/PCA observations in order to obtain broad band (1-200 keV) spectra and light curves of XTE J1739-302 and investigate its X-ray spectrum and temporal variability. We have found that XTE J1739-302 follows a much more complex behaviour than expected. Far from presenting a regular variability pattern, XTE J1739-302 shows periods of high, intermediate, and low flaring activity.Comment: 9 pages, 7 figures, accepted for publication in A&
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