48 research outputs found

    Inter- and intrachromosomal asynchrony of cell division cycle events in root meristem cells of Allium cepa: possible connection with gradient of cyclin B-like proteins

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    Alternate treatments of Allium cepa root meristems with hydroxyurea (HU) and caffeine give rise to extremely large and highly elongated cells with atypical images of mitotic divisions, including internuclear asynchrony and an unknown type of interchromosomal asynchrony observed during metaphase-to-anaphase transition. Another type of asynchrony that cannot depend solely on the increased length of cells was observed following long-term incubation of roots with HU. This kind of treatment revealed both cell nuclei entering premature mitosis and, for the first time, an uncommon form of mitotic abnormality manifested in a gradual condensation of chromatin (spanning from interphase to prometaphase). Immunocytochemical study of polykaryotic cells using anti-ÎČ tubulin antibodies revealed severe perturbations in the microtubular organization of preprophase bands. Quantitative immunofluorescence measurements of the control cells indicate that the level of cyclin B-like proteins reaches the maximum at the G2 to metaphase transition and then becomes reduced during later stages of mitosis. After long-term incubation with low doses of HU, the amount of cyclin B-like proteins considerably increases, and a significant number of elongated cells show gradients of these proteins spread along successive regions of the perinuclear cytoplasm. It is suggested that there may be a direct link between the effects of HU-mediated deceleration of S- and G2-phases and an enhanced concentration of cyclin B-like proteins. In consequence, the activation of cyclin B-CDK complexes gives rise to an abnormal pattern of premature mitotic chromosome condensation with biphasic nuclear structures having one part of chromatin decondensed, and the other part condensed

    Complex Processes from Dynamical Architectures with Time-Scale Hierarchy

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    The idea that complex motor, perceptual, and cognitive behaviors are composed of smaller units, which are somehow brought into a meaningful relation, permeates the biological and life sciences. However, no principled framework defining the constituent elementary processes has been developed to this date. Consequently, functional configurations (or architectures) relating elementary processes and external influences are mostly piecemeal formulations suitable to particular instances only. Here, we develop a general dynamical framework for distinct functional architectures characterized by the time-scale separation of their constituents and evaluate their efficiency. Thereto, we build on the (phase) flow of a system, which prescribes the temporal evolution of its state variables. The phase flow topology allows for the unambiguous classification of qualitatively distinct processes, which we consider to represent the functional units or modes within the dynamical architecture. Using the example of a composite movement we illustrate how different architectures can be characterized by their degree of time scale separation between the internal elements of the architecture (i.e. the functional modes) and external interventions. We reveal a tradeoff of the interactions between internal and external influences, which offers a theoretical justification for the efficient composition of complex processes out of non-trivial elementary processes or functional modes

    An ethnographic investigation of maternity healthcare experience of immigrants in rural and urban Alberta, Canada

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    Background: Canada is among the top immigrant-receiving nations in the world. Immigrant populations may face structural and individual barriers in the access to and navigation of healthcare services in a new country. The aims of the study were to (1) generate new understanding of the processes that perpetuate immigrant disadvantages in maternity healthcare, and (2) devise potential interventions that might improve maternity experiences and outcomes for immigrant women in Canada. Methods: The study utilized a qualitative research approach that focused on ethnographic research design and data analysis contextualized within theories of organizational behaviour and critical realism. Data were collected over 2.5 years using focus groups and in-depth semistructured interviews with immigrant women (n = 34), healthcare providers (n = 29), and social service providers (n = 23) in a Canadian province. Purposive samples of each subgroup were generated, and recruitment and data collection – including interpretation and verification of translations – were facilitated through the hiring of community researchers and collaborations with key informants. Results: The findings indicate that (a) communication difficulties, (b) lack of information, (c) lack of social support (isolation), (d) cultural beliefs, e) inadequate healthcare services, and (f) cost of medicine/services represent potential barriers to the access to and navigation of maternity services by immigrant women in Canada. Having successfully accessed and navigated services, immigrant women often face additional challenges that influence their level of satisfaction and quality of care, such as lack of understanding of the informed consent process, lack of regard by professionals for confidential patient information, short consultation times, short hospital stays, perceived discrimination/stereotyping, and culture shock. Conclusions: Although health service organizations and policies strive for universality and equality in service provision, personal and organizational barriers can limit care access, adequacy, and acceptability for immigrant women. A holistic healthcare approach must include health informational packages available in different languages/media. Health care professionals who care for diverse populations must be provided with training in cultural competence, and monitoring and evaluation programs to ameliorate personal and systemic discrimination

    Development of burnout over time and the causal order of the three dimensions of burnout among male and female GPs. A three-wave panel study

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    <p>Abstract</p> <p>Background</p> <p>A good understanding of the aetiology and development of burnout facilitates its early recognition, prevention and treatment. Since the prevalence and onset of this health problem is thought to differ between men and women, sex must be taken into account. This study aims to assess the prevalence and development of burnout among General Practitioners (GPs). In this population the prevalence of burnout is high.</p> <p>Methods</p> <p>We performed a three-wave longitudinal study (2002, 2004, 2006) in a random sample of Dutch GPs. Data were collected by means of self-report questionnaires including the Maslach Burnout Inventory. Our final sample consisted of 212 GPs of which 128 were male. Data were analyzed by means of SPSS and LISREL.</p> <p>Results</p> <p>Results indicate that about 20% of the GPs is clinically burned out (but still working). For both sexes, burnout decreased after the first wave, but increased again after the second wave. The prevalence of depersonalization is higher among men. With regard to the process of burnout we found that for men burnout is triggered by depersonalization and by emotional exhaustion for women.</p> <p>Conclusions</p> <p>As regards the developmental process of burnout, we found evidence for the fact that the aetiological process of burnout, that is the causal order of the three burnout dimensions, differs between men and women. These sex differences should be taken into account in vocational training and policy development, especially since general practice is feminizing rapidly.</p

    Registered Nurses’ Decisions Around Referral of Residents With Urinary Tract Infections: A Retrospective Cohort Study

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    Background: Referral of residents with urinary tract infections (UTIs) in residential aged care facilities (RACFs) to hospital are common. However, there is limited information on what influences Registered Nurses’ (RN) decision-making process. Aim: To investigate resident factors that influence RN’s decisions to escalate care. Design: A retrospective cohort approach audited electronic clinical records of residents with UTIs. Methods: Data were extracted from the electronic database and analyzed using descriptive and regression analysis. Approval was obtained from both the RACFs and University Human Research Ethics Committee. Results: There was a higher likelihood of being referred to hospital if residents were female, had had a past fall, had related comorbidity, or had abnormal vital signs. However, being older and having a urinary catheter were protective factors for referral by the RN. Conclusion: Referral of residents with UTIs by RNs to hospital is common in RACFs. Resident characteristics such as abnormal vital signs, past falls, and presence of comorbidity influence referrals by RNs. Nurse Practitioners dedicated to the RACFs could complement the role of a general practitioner. UTI-specific escalation protocols can assist RNs to make decisions about referrals. RNs’ related risk factors also need to be examined to understand other influencing factors
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