2,587 research outputs found

    In and out of Madagascar : dispersal to peripheral islands, insular speciation and diversification of Indian Ocean daisy trees (Psiadia, Asteraceae)

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    This study was supported by the European Union’s HOTSPOTS Training Network (MEST-2005-020561)Madagascar is surrounded by archipelagos varying widely in origin, age and structure. Although small and geologically young, these archipelagos have accumulated disproportionate numbers of unique lineages in comparison to Madagascar, highlighting the role of waif-dispersal and rapid in situ diversification processes in generating endemic biodiversity. We reconstruct the evolutionary and biogeographical history of the genus Psiadia (Asteraceae), a plant genus with near equal numbers of species in Madagascar and surrounding islands. Analyzing patterns and processes of diversification, we explain species accumulation on peripheral islands and aim to offer new insights on the origin and potential causes for diversification in the Madagascar and Indian Ocean Islands biodiversity hotspot. Our results provide support for an African origin of the group, with strong support for non-monophyly. Colonization of the Mascarenes took place by two evolutionary distinct lineages from Madagascar, via two independent dispersal events, each unique for their spatial and temporal properties. Significant shifts in diversification rate followed regional expansion, resulting in co-occurring and phenotypically convergent species on high-elevation volcanic slopes. Like other endemic island lineages, Psiadia have been highly successful in dispersing to and radiating on isolated oceanic islands, typified by high habitat diversity and dynamic ecosystems fuelled by continued geological activity. Results stress the important biogeographical role for Rodrigues in serving as an outlying stepping stone from which regional colonization took place. We discuss how isolated volcanic islands contribute to regional diversity by generating substantial numbers of endemic species on short temporal scales. Factors pertaining to the mode and tempo of archipelago formation and its geographical isolation strongly govern evolutionary pathways available for species diversification, and the potential for successful diversification of dispersed lineages, therefore, appears highly dependent on the timing of arrival, as habitat and resource properties change dramatically over the course of oceanic island evolution.Publisher PDFPeer reviewe

    The MCS package in a non-budgeting organisation: A case study of Mainfreight

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    Purpose - Budgets are commonly viewed as a central component of management control systems (MCS). The beyond budgeting literature argues that managers can develop other controls to replace budgets. The purpose of this paper is to examine the MCS package of an organisation which has never in its history had a traditional budget. Design/methodology/approach - The authors carry out an ethnomethodology informed case study at Mainfreight, a large multinational logistics company headquartered in New Zealand. Data were collected from interviews with managers and accountants, internal company documents, published corporate histories, a company presentation, the corporate Web site and site visits. Findings - The authors found that Mainfreight's MCS package was explicitly designed based on cultural and administrative systems which supported the planning, cybernetic and reward systems managers used to monitor key drivers of short-and long-term performance with a focus on profitability. Research limitations/implications - The implication of the finding is that a more holistic view of the MCS package is necessary to understand how control is achieved within organisations that have moved beyond budgeting. Practical implications - The authors show that organisations can operate without traditional budgets and still maintain a high level of control by developing appropriate cultural and administrative control systems that are internally consistent with their planning, cybernetic and reward systems. Originality/value - The scarcity of organisations that have never had budgets limits opportunities to investigate an MCS package intended to function without budgets. This unique case setting reveals the design of an integrated non-budgeting MCS package

    The Influence of Intense Tai Chi Training on Physical Performance and Hemodynamic Outcomes in Transitionally Frail, Older Adults

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    Background. Few data exist to evaluate whether Tai Chi (TC) training improves physical performance and hemodynamic outcomes more than a wellness education (WE) program does among older fallers transitioning to frailty. Methods. This 48-week randomized clinical trial was provided at 10 matched pairs of congregate living facilities in the Atlanta metropolitan area to 291 women and 20 men, who were transitionally frail, ≥70 years old, and had fallen at least once within the past year. Pairs of facilities were randomized to either TC exercise (n = 158) or WE (control) interventions (n = 153) over 48 weeks. Physical performance (freely chosen gait speed, reach, chair-rises, 360° turn, picking up an object from the floor, and single limb support) and hemodynamic outcomes (heart rate and blood pressure) were obtained at baseline and after 4, 8, and 12 months. Results. Mean percent change (baseline to 1 year) for gait speed increased similarly in both cohorts (TC: 9.1% and WE: 8.2%; p =.78). However, time to complete three chair-rises decreased 12.3% for TC and increased 13.7% for WE (p =.006). Baseline to 1 year mean percent change decreased among TC and increased within WE cohorts for: body mass index (-2.3% vs 1.8%; p <.0001), systolic blood pressure (-3.4% vs 1.7%; p =.02), and resting heart rate (-5.9% vs 4.6%; p <.0001). Conclusions. TC significantly improved chair-rise and cardiovascular performance. Because TC training reduced fall occurrences in this cohort, factors influencing functional and cardiovascular improvements may also favorably impact fall event

    Formal Calibration Methodology for CFD Model Development to Support the Operation of Energy Efficient Buildings

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    Computational Fluid Dynamics (CFD) is a robust tool for modeling interactions within and between fluids and solids. CFD can help understand and predict phenomena that are difficult to test experimentally leading to cleaner, healthier, and better controlled internal environments. In this research a CFD model of the internal environment of an office space will be developed. The CFD model will then be calibrated using real data taken from a well-positioned wireless sensor network and weather station. The work focuses on developing systematically calibrated CFD models for controlled environments that include clean rooms, health environments, pharmaceutical storage rooms and information and communication technology locations, utilizing wireless sensor networks. The calibrated CFD model will be used to optimize the positions of the physical sensors for the control of energy efficient internal environments by building operators. This could result in significant energy and economic savings and lead to more accurately controlled internal environments

    Supporting 'design for reuse' with modular design

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    Engineering design reuse refers to the utilization of any knowledge gained from the design activity to support future design. As such, engineering design reuse approaches are concerned with the support, exploration, and enhancement of design knowledge prior, during, and after a design activity. Modular design is a product structuring principle whereby products are developed with distinct modules for rapid product development, efficient upgrades, and possible reuse (of the physical modules). The benefits of modular design center on a greater capacity for structuring component parts to better manage the relation between market requirements and the designed product. This study explores the capabilities of modular design principles to provide improved support for the engineering design reuse concept. The correlations between modular design and 'reuse' are highlighted, with the aim of identifying its potential to aid the little-supported process of design for reuse. In fulfilment of this objective the authors not only identify the requirements of design for reuse, but also propose how modular design principles can be extended to support design for reuse

    The interplay between extrinsic and intrinsic factors in determining migration decisions in brown trout (Salmo trutta): An experimental study

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    Many species are capable of facultative migration, but the relative roles of extrinsic versus intrinsic factors in generating diverse migratory tactics remain unclear. Here we explore the proximate drivers of facultative migration in brown trout in an experimental laboratory setting. The effects of reduced food, as a putative environmental cue, were examined in two populations: one that exhibits high rates of anadromy (sea-migration) in nature, and one that does not exhibit anadromy in nature. Juveniles derived from wild-caught parents were reared for two years under four environmental treatments: low food in years 1 and 2 (Low-Low); high food in years 1 and 2 (High-High), low food in year 1 and high in year 2 (Low-High), and vice versa (High-Low). Food restriction had a significant effect on migratory tactics, with the frequency of smolts (juveniles choosing migration) highest in the Low-Low treatment in both populations. No individuals became smolts in the High-High treatment, and intermediate smolting rates were observed in the Low-High and High-Low treatments. Higher overall smolting rates in the naturally anadromous population suggested an inherited component to anadromy/migration decisions, but both populations showed variability in migratory tactics. Importantly, some fish from the naturally non-anadromous population became smolts in the experiment, implying the capacity for migration was lying ‘dormant’, but they exhibited lower hypo-osmoregulatory function than smolts from the naturally anadromous population. Tactic frequencies in the naturally anadromous population were more affected by food in the 2nd year, while food in the 1st year appeared more important for the naturally non-anadromous population. Migratory tactics were also related to sex, but underpinned in both sexes by growth in key periods, size and energetic state. Collectively these results reveal how migration decisions are shaped by a complex interplay between extrinsic and intrinsic factors, informing our ability to predict how facultatively migratory populations will respond to environmental change

    LC3B globular structures correlate with survival in esophageal adenocarcinoma

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    Background: Esophageal adenocarcinoma has the fastest growing incidence of any solid tumor in the Western world. Prognosis remains poor with overall five-year survival rates under 25 %. Only a limited number of patients benefit from chemotherapy and there are no biomarkers that can predict outcome. Previous studies have indicated that induction of autophagy can influence various aspects of tumor cell biology, including chemosensitivity. The objective of this study was to assess whether expression of the autophagy marker (LC3B) correlated with patient outcome. Methods: Esophageal adenocarcinoma tumor tissue from two independent sites, was examined retrospectively. Tumors from 104 neoadjuvant naïve patients and 48 patients post neoadjuvant therapy were assembled into tissue microarrays prior to immunohistochemical analysis. Kaplan-Meier survival curves and log-rank tests were used to assess impact of LC3B expression on survival. Cox regression was used to examine association with clinical risk factors. Results: A distinct globular pattern of LC3B expression was found to be predictive of outcome in both patient groups, irrespective of treatment (p < 0.001). Multivariate analysis found that this was a strong independent predictor of poor prognosis (p < 0.001). Conclusions: This distinctive staining pattern of LC3B represents a novel prognostic marker for resectable esophageal adenocarcinoma
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