172 research outputs found

    E151 (sym15), A Pleiotropic Mutant of Pea (Pisum sativum L.), Displays Low Nodule Number, Enhanced Mycorrhizae, Delayed Lateral Root Emergence, and High Root Cytokinin Levels

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    In legumes, the formation of rhizobial and mycorrhizal root symbioses is a highly regulated process which requires close communication between plant and microorganism. Plant mutants that have difficulties establishing symbioses are valuable tools for unravelling the mechanisms by which these symbioses are formed and regulated. Here E151, a mutant of Pisum sativum cv. Sparkle, was examined to characterize its root growth and symbiotic defects. The symbioses in terms of colonization intensity, functionality of micro-symbionts, and organ dominance were compared between the mutant and wild type. The endogenous cytokinin (CK) and abscisic acid (ABA) levels and the effect of the exogenous application of these two hormones were determined. E151 was found to be a low and delayed nodulator, exhibiting defects in both the epidermal and cortical programmes though a few mature and functional nodules develop. Mycorrhizal colonization of E151 was intensified, although the fungal functionality was impaired. Furthermore, E151 displayed an altered lateral root (LR) phenotype compared with that of the wild type whereby LR emergence is initially delayed but eventually overcome. No differences in ABA levels were found between the mutant and the wild type, but non-inoculated E151 exhibited significantly high CK levels. It is hypothesized that CK plays an essential role in differentially mediating the entry of the two micro-symbionts into the cortex; whereas it would inhibit the entry of the rhizobia in that tissue, it would promote that of the fungus. E151 is a developmental mutant which may prove to be a useful tool in further understanding the role of hormones in the regulation of beneficial root symbioses

    The Reimposition of Capital Punishment in New Jersey: The Role of Prosecutorial Discretion

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    After Furman v. Georgia held that state statutes that allow for the imposition of the death penalty in an arbitrary and capricious manner violate the Constitution, the states were forced to rewrite their capital punishment statutes. New Jersey adopted a new statute in 1982. Despite the attempt of the New Jersey legislature to comply with the mandate of Furman, application of the statute has resulted in clear and significant discrepancies in the treatment of potentially capital defendants based on the race of the victim, the county of jurisdiction, and the race of the defendant. This article details a large study of all homicide defendants (other than those charged with vehicular manslaughter) where the death occurred after the effective date of the New Jersey statute. To determine whether the imposition of death was unconstitutionally arbitrary, the study examined both legal and extralegal factors that might predict whether the defendant would be sentenced to death. Unlike many previous studies reviewed by the article, which only compared defendants charged with crimes punishable by death, this study looked at the entire pool of potential homicide defendants. By separating case processing into discrete stages, the study shows the enormous role that prosecutorial discretion plays in determining whether a defendant receives a death sentence. While the facts of the case would have allowed the prosecutor to seek the death penalty in 404 cases, only 94 of those cases were brought to capital trial. This system of selecting defendants for capital prosecution has constitutional implications

    US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

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    This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference

    Patients’ Perceptions and Experiences of Familial Hypercholesterolemia, Cascade Genetic Screening and Treatment

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    Background: Familial hypercholesterolemia (FH) is a serious genetic disorder affecting approximately 1 in every 300 to 500 individuals and is characterised by excessively high low-density lipoprotein (LDL) cholesterol levels, substantially increased risk of early-onset coronary heart disease (CHD) and premature mortality. If FH is untreated, it leads to a greater than 50 % risk of CHD in men by the age of 50 and at least 30 % in women by the age of 60. FH can be diagnosed through genetic screening and effectively managed through pharmacological treatment and lifestyle changes. Purpose: Familial hypercholesterolemia (FH) is a genetic health condition that increases the risk of cardiovascular disease. Although FH can be effectively managed with appropriate pharmacological and dietary interventions, FH detection rate through genetic screening remains low. The present study explored perceptions and experiences of FH patients (N = 18) involved in a genetic cascade screening programme. Methods: Face-to-face interviews were conducted to assess patients’ knowledge and understanding of FH, explore factors linked to adherence to health-protective behaviours and examine perceptions of genetic screening. Results: Thematic analysis of interviews revealed four themes: disease knowledge, severity of FH, lifestyle behavioural change and barriers to cascade screening and treatment. Participants recognised FH as a permanent, genetic condition that increased their risk of CHD and premature mortality. Many participants dismissed the seriousness of FH and the importance of lifestyle changes because they perceived it to be effectively managed through medication. Despite positive attitudes toward screening, many participants reported that relatives were reluctant to attend screening due to their relatives’ ‘fatalistic’ outlook or low motivation. Participants believed that they had insufficient authority or control to persuade family members to attend screening and welcomed greater hospital assistance for contact with relatives. Conclusions: Findings support the adoption of direct methods of recruitment to cascade screening led by medical professionals, who were perceived as having greater authority. Other implications included the need for clinicians to provide clear information, particularly to those who are asymptomatic, related to the seriousness of FH and the necessity for adherence to medication and lifestyle changes

    Effects of two contrasting canopy manipulations on growth and water use of London plane (Platanus x acerifolia) trees

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    Aims: Two contrasting canopy manipulations were compared to unpruned controls on London plane trees, to determine the effects on canopy regrowth, soil and leaf water relations. Methods: ‘Canopy reduction’, was achieved by removing the outer 30 % length of all major branches and ‘canopy thinning’, by removing 30 % of lateral branches arising from major branches. Results: Total canopy leaf areas recovered within two and three years of pruning for the canopy-thinned and reduced trees respectively. Canopy reduction increased mean leaf size, nitrogen concentration, canopy leaf area density and conserved soil moisture for up to 3 years, whereas canopy thinning had no effects. Another experiment compared more severe canopy reduction to unpruned trees. This produced a similar growth response to the previous experiment, but soil moisture was conserved nearer to the trunk. Analysis of 13C and 18O signals along with leaf water relations and soil moisture data suggested that lower boundary layer conductance within the canopy-reduced trees restricted tree water use, whereas for the canopy-thinned trees the opposite occurred. Conclusions: Only canopy reduction conserved soil moisture and this was due to a combination of reduced total canopy leaf area and structural changes in canopy architecture

    Genomic characterization of large rearrangements of the LDLR gene in Czech patients with familial hypercholesterolemia

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    <p>Abstract</p> <p>Background</p> <p>Mutations in the <it>LDLR </it>gene are the most frequent cause of Familial hypercholesterolemia, an autosomal dominant disease characterised by elevated concentrations of LDL in blood plasma. In many populations, large genomic rearrangements account for approximately 10% of mutations in the <it>LDLR </it>gene.</p> <p>Methods</p> <p>DNA diagnostics of large genomic rearrangements was based on Multiple Ligation dependent Probe Amplification (MLPA). Subsequent analyses of deletion and duplication breakpoints were performed using long-range PCR, PCR, and DNA sequencing.</p> <p>Results</p> <p>In set of 1441 unrelated FH patients, large genomic rearrangements were found in 37 probands. Eight different types of rearrangements were detected, from them 6 types were novel, not described so far. In all rearrangements, we characterized their exact extent and breakpoint sequences.</p> <p>Conclusions</p> <p>Sequence analysis of deletion and duplication breakpoints indicates that intrachromatid non-allelic homologous recombination (NAHR) between <it>Alu </it>elements is involved in 6 events, while a non-homologous end joining (NHEJ) is implicated in 2 rearrangements. Our study thus describes for the first time NHEJ as a mechanism involved in genomic rearrangements in the <it>LDLR </it>gene.</p

    Metal-enriched, subkiloparsec gas clumps in the circumgalactic medium of a faint z = 2.5 galaxy★

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    We report the serendipitous detection of a 0.2 L∗^*, Lyman-α\alpha emitting galaxy at redshift 2.5 at an impact parameter of 50 kpc from a bright background QSO sightline. A high-resolution spectrum of the QSO reveals a partial Lyman-limit absorption system (NHI=1016.94±0.10N_\mathrm{HI}=10^{16.94\pm0.10} cm−2^{-2}) with many associated metal absorption lines at the same redshift as the foreground galaxy. Using photoionization models that carefully treat measurement errors and marginalise over uncertainties in the shape and normalisation of the ionizing radiation spectrum, we derive the total hydrogen column density NH=1019.4±0.3N_\mathrm{H}=10^{19.4\pm0.3} cm−2^{-2}, and show that all the absorbing clouds are metal enriched, with Z=0.1Z=0.1-0.6Z⊙0.6 Z_\odot. These metallicities and the system's large velocity width (436436 km \,s−1^{-1}) suggest the gas is produced by an outflowing wind. Using an expanding shell model we estimate a mass outflow rate of ∌5M⊙ \sim5 M_\odot\,yr−1^{-1}. Our photoionization model yields extremely small sizes (<<100-500 pc) for the absorbing clouds, which we argue are typical of high column density absorbers in the circumgalactic medium (CGM). Given these small sizes and extreme kinematics, it is unclear how the clumps survive in the CGM without being destroyed by hydrodynamic instabilities. The small cloud sizes imply that even state-of-the-art cosmological simulations require more than a 10001000-fold improvement in mass resolution to resolve the hydrodynamics relevant for cool gas in the CGM.Comment: Fixed an incorrect reference to D'Odorico & Petitjean 2001, A&A, 370, 729. Data and code used for the paper are at https://github.com/nhmc/LA

    Applicant perspectives during selection

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    We provide a comprehensive but critical review of research on applicant reactions to selection procedures published since 2000 (n = 145), when the last major review article on applicant reactions appeared in the Journal of Management. We start by addressing the main criticisms levied against the field to determine whether applicant reactions matter to individuals and employers (“So what?”). This is followed by a consideration of “What’s new?” by conducting a comprehensive and detailed review of applicant reaction research centered upon four areas of growth: expansion of the theoretical lens, incorporation of new technology in the selection arena, internationalization of applicant reactions research, and emerging boundary conditions. Our final section focuses on “Where to next?” and offers an updated and integrated conceptual model of applicant reactions, four key challenges, and eight specific future research questions. Our conclusion is that the field demonstrates stronger research designs, with studies incorporating greater control, broader constructs, and multiple time points. There is also solid evidence that applicant reactions have significant and meaningful effects on attitudes, intentions, and behaviors. At the same time, we identify some remaining gaps in the literature and a number of critical questions that remain to be explored, particularly in light of technological and societal changes
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