1,001 research outputs found

    A study of floral development in Asparagus officinalis L

    Get PDF
    Asparagus officinalis L. is typically classified as a dioecious species. However, in all-male hybrid cultivars, a percentage of individuals within a population exhibit a persistent perfect flowering (hermaphrodite) phenotype. Floral meristem development was divided into eight distinct stages of development and those developmental stages were compared in UC157 male, UC157 female, and 32/83 hermaphrodite individuals using scanning electron microscopy (SEM). In females, anthers abort between stages five and six. In males, style development is halted at stage eight. Hermaphrodites exhibit normal development of both anthers and styles. Within the 32/83 cultivar, the number of developing carpels can vary and some unusual pistil types are observed. The timing of floral organ development is delayed in females compared to males and hermaphrodites. However, once a meristem becomes committed to flowering, the development of complete floral organs occurs in approximately three days. An additional four to seven days is required before anthesis occurs or pistils become receptive to pollen. Protein profiles of three day post-emergent spears show distinct qualitative and quantitative differences between sex types. Distinctly different proteins are expressed in vegetative cladophyll tissue and floral bud tissues as well. Floral homeotic genes in other plant species contain a DNA binding domain (MADS box) common to a family of transcription factors. MADS boxes were cloned from male asparagus via PCR technology. Eight unique asparagus MADS box clones group into three distinct classes based on distance matrix analysis. UPGMA analysis of amino acid sequences shows five of the asparagus clones clustering independently from other known plant MADS domains which suggests they may represent a new class of MADS domain. The remaining three asparagus clones cluster with the Arabidopsis Agamous MADS domain. Computer modeling indicates the new class of MADS domain has some similarity in secondary protein structure with the Agamous MADS domain from Arabidopsis

    National Versus Private-Label Brands: Dynamics, Conceptual Framework, And Empirical Perspective

    Get PDF
    Motivated by profits and their growing power in the marketplace, retailers have been expanding their private-label brands to include more categories of consumer products and differentiation on quality to reach different consumer segments. This global phenomenon is adversely impacting the performance of national brands, thus creating a conflict between two powerful parties – manufacturers of national brands and their large retailers who are supposed to be their helping hands in the marketplace.   In this paper, the authors develop a conceptual framework, which captures the complexity and multidimensionality of the situation – the stakeholders involved, the interest and power of each, the relationships among them, various strategies they employ, and the outcomes of the conflict. Several hypotheses were examined and tested through the empirical part of this study; for example, would the powers of these parties determine who is the loser and who is the winner or will the verdict be in the hands of the consumers? The study surveyed 281 consumers to assess their attitudes toward and preferences of store brands versus national brands across product categories and the underlying motivations. The paper concludes with recommendations for retailers and national brand manufacturers to win the hearts of consumers rather than exhaust their resources in the conflict

    Can screening and brief intervention lead to population-level reductions in alcohol-related harm?

    Get PDF
    A distinction is made between the clinical and public health justifications for screening and brief intervention (SBI) against hazardous and harmful alcohol consumption. Early claims for a public health benefit of SBI derived from research on general medical practitioners' (GPs') advice on smoking cessation, but these claims have not been realized, mainly because GPs have not incorporated SBI into their routine practice. A recent modeling exercise estimated that, if all GPs in England screened every patient at their next consultation, 96% of the general population would be screened over 10 years, with 70-79% of excessive drinkers receiving brief interventions (BI); assuming a 10% success rate, this would probably amount to a population-level effect of SBI. Thus, a public health benefit for SBI presupposes widespread screening; but recent government policy in England favors targeted versus universal screening, and in Scotland screening is based on new registrations and clinical presentation. A recent proposal for a national screening program was rejected by the UK National Health Service's National Screening Committee because 1) there was no good evidence that SBI led to reductions in mortality or morbidity, and 2) a safe, simple, precise, and validated screening test was not available. Even in countries like Sweden and Finland, where expensive national programs to disseminate SBI have been implemented, only a minority of the population has been asked about drinking during health-care visits, and a minority of excessive drinkers has been advised to cut down. Although there has been research on the relationship between treatment for alcohol problems and population-level effects, there has been no such research for SBI, nor have there been experimental investigations of its relationship with population-level measures of alcohol-related harm. These are strongly recommended. In this article, conditions that would allow a population-level effect of SBI to occur are reviewed, including their political acceptability. It is tentatively concluded that widespread dissemination of SBI, without the implementation of alcohol control measures, might have indirect influences on levels of consumption and harm but would be unlikely on its own to result in public health benefits. However, if and when alcohol control measures were introduced, SBI would still have an important role in the battle against alcohol-related harm

    Cluster randomized controlled trial protocol: addressing reproductive coercion in health settings (ARCHES)

    Get PDF
    Background\ud Women ages 16–29 utilizing family planning clinics for medical services experience higher rates of intimate partner violence (IPV) and reproductive coercion (RC) than their same-age peers, increasing risk for unintended pregnancy and related poor reproductive health outcomes. Brief interventions integrated into routine family planning care have shown promise in reducing risk for RC, but longer-term intervention effects on partner violence victimization, RC, and unintended pregnancy have not been examined.\ud \ud Methods/Design\ud The ‘Addressing Reproductive Coercion in Health Settings (ARCHES)’ Intervention Study is a cluster randomized controlled trial evaluating the effectiveness of a brief, clinician-delivered universal education and counseling intervention to reduce IPV, RC and unintended pregnancy compared to standard-of-care in family planning clinic settings. The ARCHES intervention was refined based on formative research. Twenty five family planning clinics were randomized (in 17 clusters) to either a three hour training for all family planning clinic staff on how to deliver the ARCHES intervention or to a standard-of-care control condition. All women ages 16–29 seeking care in these family planning clinics were eligible to participate. Consenting clients use laptop computers to answer survey questions immediately prior to their clinic visit, a brief exit survey immediately after the clinic visit, a first follow up survey 12–20 weeks after the baseline visit (T2), and a final survey 12 months after the baseline (T3). Medical record chart review provides additional data about IPV and RC assessment and disclosure, sexual and reproductive health diagnoses, and health care utilization. Of 4009 women approached and determined to be eligible based on age (16–29 years old), 3687 (92 % participation) completed the baseline survey and were included in the sample.\ud \ud Discussion\ud The ARCHES Intervention Study is a community-partnered study designed to provide arigorous assessment of the short (3-4 months) and long-term (12 months) effects of a brief, clinician-delivered universal education and counseling intervention to reduce IPC, RC and unintended pregnancy in family planning clinic settings. The trial features a cluster randomized controlled trial design, a comprehensive data collection schedule and a large sample size with excellent retention.\ud \ud Trial Registration\ud ClinicialTrials.gov NCT01459458. Registered 10 October 2011

    Lions and Prions and Deer Demise

    Get PDF
    Background: Contagious prion diseases – scrapie of sheep and chronic wasting disease of several species in the deer family – give rise to epidemics that seem capable of compromising host population viability. Despite this prospect, the ecological consequences of prion disease epidemics in natural populations have received little consideration. Methodology/Principal Findings: Using a cohort study design, we found that prion infection dramatically lowered survival of free-ranging adult (.2-year-old) mule deer (Odocoileus hemionus): estimated average life expectancy was 5.2 additional years for uninfected deer but only 1.6 additional years for infected deer. Prion infection also increased nearly fourfold the rate of mountain lions (Puma concolor) preying on deer, suggesting that epidemics may alter predator–prey dynamics by facilitating hunting success. Despite selective predation, about one fourth of the adult deer we sampled were infected. High prevalence and low survival of infected deer provided a plausible explanation for the marked decline in this deer population since the 1980s. Conclusion: Remarkably high infection rates sustained in the face of intense predation show that even seemingly complete ecosystems may offer little resistance to the spread and persistence of contagious prion diseases. Moreover, the depression of infected populations may lead to local imbalances in food webs and nutrient cycling in ecosystems in which deer ar

    Epstein-Barr virus transcription factor Zta acts through distal regulatory elements to directly control cellular gene expression

    Get PDF
    Lytic replication of the human gamma herpes virus Epstein-Barr virus (EBV) is an essential prerequisite for the spread of the virus. Differential regulation of a limited number of cellular genes has been reported in B-cells during the viral lytic replication cycle. We asked whether a viral bZIP transcription factor, Zta (BZLF1, ZEBRA, EB1), drives some of these changes. Using genome-wide chromatin immunoprecipitation coupled to next-generation DNA sequencing (ChIP-seq) we established a map of Zta interactions across the human genome. Using sensitive transcriptome analyses we identified 2263 cellular genes whose expression is significantly changed during the EBV lytic replication cycle. Zta binds 278 of the regulated genes and the distribution of binding sites shows that Zta binds mostly to sites that are distal to transcription start sites. This differs from the prevailing view that Zta activates viral genes by binding exclusively at promoter elements. We show that a synthetic Zta binding element confers Zta regulation at a distance and that distal Zta binding sites from cellular genes can confer Zta-mediated regulation on a heterologous promoter. This leads us to propose that Zta directly reprograms the expression of cellular genes through distal elements
    corecore