94 research outputs found

    Comparative life-history traits in a fig wasp community: implications for community structure

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    1. Whether life-history traits can determine community composition and structure is an important question that has been well explored theoretically, but has received scant empirical attention. Life-history traits of a seven-member community of galler and parasitoid fig wasp species (Chalcidoidea), developing within the inflorescences (syconia) of Ficus racemosa (Moraceae) in India, were determined and used to examine community structure and ecology. 2. Gallers were pro-ovigenic (all eggs are mature upon adult emergence) whereas parasitoids were synovigenic (eggs mature progressively during adult lifespan). Initial egg load was correlated with body size for some species, and there was a trade-off between egg number and egg size across all species. Although all species completed their development and left the syconium concurrently, they differed in their adult and pre-adult lifespans. Providing sucrose solutions increased parasitoid lifespan but had no effect on the longevity of some galler species. While feeding regimes and body size affected longevity in most species, an interaction effect between these variables was detected for only one species. 3. Life-history traits of wasp species exhibited a continuum in relation to their arrival sequence at syconia for oviposition during syconium development, and therefore reflected their ecology. The largest number of eggs, smallest egg sizes, and shortest longevities were characteristic of the earliest-arriving galling wasps at the smallest, immature syconia; the converse characterised the later-arriving parasitoids at the larger, already parasitised syconia. Thus life history is an important correlate of community resource partitioning and can be used to understand community structure. 4. This is the first comprehensive study of life-history traits in a fig wasp community. The comparative approach revealed constraints and flexibility in trait evolution

    Cervical cancer metastasis to the brain: A case report and review of literature

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    Background: Intracranial metastasis from cervical cancer is a rare occurrence. Methods: In this study we describe a case of cervical cancer metastasis to the brain and perform an extensive review of literature from 1956 to 2016, to characterize clearly the clinical presentation, treatment options, molecular markers, targeted therapies, and survival of patients with this condition. Results: An elderly woman with history of cervical cancer in remission, presented 2 years later with a right temporo-parietal tumor, which was treated with surgery and subsequent stereotactic radiosurgery (SRS) to the resection cavity. She then returned 5 months later with a second solitary right lesion; she again underwent surgery and SRS to the resection cavity with no signs of recurrence 6 months later. According to the reviewed literature, the most common clinical presentation included females with median age of 48 years; presenting symptoms such as headache, weakness/hemiplegia/hemiparesis, seizure, and altered mental status (AMS)/confusion; multiple lesions mostly supratentorially located; poorly differentiated squamous cell carcinoma; and additional recurrences at other sites. The best approach to treatment is a multimodal plan, consisting of SRS or whole brain radiation therapy (WBRT) for solitary brain metastases followed by chemotherapy for systemic disease, surgery and WBRT for solitary brain lesions without systemic disease, and SRS or WBRT followed by chemotherapy for palliative care. The overall prognosis is poor with a mean and median survival time from diagnosis of brain metastasis of 7 and 4.6 months, respectively. Conclusion: Future efforts through large prospective randomized trials are warranted to better describe the clinical presentation and identify more effective treatment plans

    Re-assessing co-movements among G7 equity markets: evidence from iShares

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    iShares funds are products designed to mimic the movements of MSCI stock market indices. Being devoid of problems associated with trading restrictions, exchange-rate fluctuations and non-synchronous trading, iShares data are better suited for measuring, firstly, equity-market co-movements and, secondly, diversification potential than national indices data; the latter data are used by most of the studies in the area. Applying recent time-varying methodology for the analysis of short- and long-term co-movements, a detailed analysis of the dynamics of the equity market linkages over the period 1996-2005 is provided. Evidence is found of increasing conditional correlations and significant time-varying long-run relationships between the US and the majority of other G7 markets since 2001, as measured by iShares. However, the extent of both short-term and long-term linkages between the G7 equity markets is lower for national indices data. Our findings suggest that (i) the results of earlier studies that are based on stock market indices should be interpreted with caution, since using these may overestimate the extent of available diversification benefits; and (ii) iShares funds do not represent perfect diversification products. These results appear to be robust to alternative model specifications, data frequency and conditioning bias

    Wastewater sludge management options for Honduras

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.Includes bibliographical references (leaves 48-50).Sludge management is a fundamental area of concern across wastewater treatment systems in Honduras. The lack of timely sludge removal has led to declining plant performance in many facilities throughout the country. In addition to maintaining treatment efficiency, proper sludge management is important for mitigating pathogen levels and providing opportunities for safe beneficial reuse of biosolids. Based on analyses of data collected at waste stabilization ponds in the municipalities of Puerto Cortes and La Lima, sludge was characterized with respect to quantities generated (accumulation rates) and quality (helminths and heavy metals content). A review was conducted of appropriate sludge treatment technologies including sludge drying beds, alkaline stabilization, acid stabilization, anaerobic digestion, and composting. These options were evaluated based on a set of selected criteria. Anaerobic digestion, alkaline stabilization, and composting were all found to be suitable methods of sludge treatment. Alkaline stabilization and composting are well suited to facilities with sufficient land. Anaerobic digestion was recommended for areas with land constraints. Treated biosolids can be beneficially used within the community and/or at a regional scale. Potential regional end-uses include soil amendment in agriculture and forestry, or for land reclamation of mined lands. Public participation and acceptance is essential for the success of a biosolids reuse program. Potential strategies for engaging the community and addressing public concerns regarding biosolids were identified.by Mahua Bhattacharya.M.Eng

    Using structural equation modeling to examine the influence of family planning social norms on modern contraceptive use in Nigeria

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    Despite high knowledge of family planning (FP) among Nigerian women, use of modern contraceptives remains low. While FP investments in Nigeria have been ongoing for decades, relatively little emphasis on contextual and structural factors may have contributed to low demand for and use of contraception. From 2009 to 2014, the Bill & Melinda Gates Foundation (BMGF) supported the Nigerian Urban Reproductive Health Initiative (NURHI) with the aim of increasing voluntary use of contraceptives among women ages 15–49 years in six Nigerian cities. A subsequent phase of NURHI was implemented in three states for the next 3 to 5 years. Using cross-sectional survey data from three cities (two exposed to NURHI, one not exposed), this study examines whether social norms around FP were related to women's use of modern contraception, and whether the relationship differed by varying levels of exposure to the program (i.e., by city). We identified three distinct FP social norms through factor analysis: norms around delaying first pregnancy; spacing or limiting pregnancies; and using contraception when the husband disagrees. Using structural equation modeling, we found that FP social norms are related to use of modern contraceptive methods, and the relationship varies by city and norm type. The observed differences suggest that this relationship depends on numerous factors at the individual, interpersonal and societal level, and this may include malleable factors influenced by the NURHI program

    Transforming the Healthcare Response to Intimate Partner Violence and Taking Best Practices to Scale

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    BACKGROUND: Intimate partner violence (IPV) is prevalent among adolescent and adult women, with significant physical, sexual, and mental health consequences. In 2011, the Institute of Medicine\u27s Clinical Preventive Services for Women consensus report recommended universal screening for violence as a component of women\u27s preventive services; this policy has been adopted by the Health Resources and Services Administration (HRSA). These policy developments require that effective clinic-based interventions be identified, easily implemented, and taken to scale. METHODS: To foster dialogue about implementing effective interventions, we convened a symposium entitled Responding to Violence Against Women: Emerging Evidence, Implementation Science, and Innovative Interventions, on May 21, 2012. Drawing on multidisciplinary expertise, the agenda integrated data on the prevalence and health impact of IPV violence, with an overview of the implementation science framework, and a panel of innovative IPV screening interventions. Recommendations were generated for developing, testing, and implementing clinic-based interventions to reduce violence and mitigate its health impact. RESULTS: The strength of evidence supporting specific IPV screening interventions has improved, but the optimal implementation and dissemination strategies are not clear. Implementation science, which seeks to close the evidence to program gap, is a useful framework for improving screening and intervention uptake and ensuring the translation of research findings into routine practice. CONCLUSIONS: Findings have substantial relevance to the broader research, clinical, and practitioner community. Our conference proceedings fill a timely gap in knowledge by informing practitioners as they strive to implement universal IPV screening and guiding researchers as they evaluate the success of implementing IPV interventions to improve women\u27s health and well-being

    CCL2 produced by the glioma microenvironment is essential for the recruitment of regulatory T cells and myeloid-derived suppressor cells

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    In many aggressive cancers, such as glioblastoma multiforme (GBM), progression is enabled by local immunosuppression driven by the accumulation of regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC). However, the mechanistic details of how Treg and MDSC are recruited in various tumors is not yet well understood. Here we report that macrophages and microglia within the glioma microenvironment produce CCL2, a chemokine that is critical for recruiting both CCR4+ Treg and CCR2+Ly-6C+ monocytic MDSC in this disease setting. In murine gliomas, we established novel roles for tumor-derived CCL20 and osteoprotegerin in inducing CCL2 production from macrophages and microglia. Tumors grown in CCL2 deficient mice failed to maximally accrue Treg and monocytic MDSC. In mixed-bone marrow chimera assays, we found that CCR4-deficient Treg and CCR2-deficient monocytic MDSC were defective in glioma accumulation. Further, administration of a small molecule antagonist of CCR4 improved median survival in the model. In clinical specimens of GBM, elevated levels of CCL2 expression correlated with reduced overall survival of patients. Lastly, we found that CD163-positive infiltrating macrophages were a major source of CCL2 in GBM patients. Collectively, our findings show how glioma cells influence the tumor microenvironment to recruit potent effectors of immunosuppression that drive progression

    Contraceptive method use trajectories among young women in Kenya: A qualitative study

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    Background Many young women experience important key life transitions during adolescence and early adulthood, such as initiation of sexual activity, first use of contraceptives, marriage, and childbirth. For young women to be able to plan and manage their lives, it is critical to understand how these life events intersect and shape their contraceptive decision-making. This study aims to explore young women's contraceptive method use trajectories, including the factors that influence contraceptive decision-making throughout adolescence and youth. Methodology In 2019, the Full Access, Full Choice project (FAFC), implemented by the University of North Carolina at Chapel Hill and the African Institute for Development Policy, conducted 30 in-depth interviews with young women aged 18–24 years in three counties in Kenya (Nairobi, Mombasa and Migori). Eligible respondents had used two or more modern contraceptive methods. Interview guides utilized a modified life history approach to capture details about respondents' contraceptive use and life experiences from the time they first used contraception until the time of interview.ResultsWe identified five separate contraceptive use trajectories based on the occurrence and timing of marriage, childbirth, and contraceptive method choice as well as various influences on contraceptive decision-making. The majority of respondents began their contraceptive journey by using male condoms or emergency contraception, but subsequent contraceptive decisions were varied across trajectories and influenced by different factors. For many women, the initiation of a non-coitally dependent method occurred after the birth of a child; for some, this was the first method used. Once women transitioned to using a non-coitally dependent method such as injectables or implants, many cycled through different methods to find one that had fewer side effects or provided the desired duration of protection. Discussion This study highlights the nuanced needs of young women throughout their adolescent and youth years in Kenya. This suggests that programs and policies need to encompass young women's diversity of experiences and motivations to best serve them

    Global typologies of coastal wetland status to inform conservation and management

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    Global-scale conservation initiatives and policy instruments rely on ecosystem indicators to track progress towards targets and objectives. A deeper understanding of indicator interrelationships would benefit these efforts and help characterize ecosystem status. We study interrelationships among 34 indicators for mangroves, saltmarsh, and seagrass ecosystems, and develop data-driven, spatially explicit typologies of coastal wetland status at a global scale. After accounting for environmental covariates and gap-filling missing data, we obtained two levels of clustering at 5 and 18 typologies, providing outputs at different scales for different end users. We generated 2,845 cells (1° (lat) × 1° (long)) globally, of which 29.7% were characterized by high land- and marine-based impacts and a high proportion of threatened species, 13.5% by high climate-based impacts, and 9.6% were refuges with lower impacts, high fish density and a low proportion of threatened species. We identify instances where specific actions could have positive outcomes for coastal wetlands across regions facing similar issues. For example, land- and marine-based threats to coastal wetlands were associated with ecological structure and function indicators, suggesting that reducing these threats may reduce habitat degradation and threats to species persistence. However, several interdimensional relationships might be affected by temporal or spatial mismatches in data. Weak relationships mean that global biodiversity maps that categorize areas by single indicators (such as threats or trends in habitat size) may not be representative of changes in other indicators (e.g., ecosystem function). By simplifying the complex global mosaic of coastal wetland status and identifying regions with similar issues that could benefit from knowledge exchange across national boundaries, we help set the scene for globally and regionally coordinated conservation
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