230 research outputs found

    Tracheal Gases, Respiratory Gas Exchange, Body Temperature and Flight in Some Tropical Cicadas

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    Fidicina mannifera Fab. (mass 3 g) can fly at a body temperature of 22°C but take-off is usually preceded by an endothermic warm-up that elevates Tth to 28 °C or higher. Warm-up is accompanied by slow, almost imperceptible, wing movements, gentle abdominal pumping and an increase in VOO2 to about 16 times the resting level. During wing-flapping in fixed flight, VOO2 increases explosively to about 70 times the resting level, and thoracic temperature rises to about 33°C. Wing-beat frequency increases with Tth. Between 25 and 34°C the mean wing-beat frequency is about 37 Hz. F. mannifera does not maintain free flight, or wing flapping in fixed flight, for more than about 100 s. Flight is supported aerobically, and we infer that exhaustion is related to depletion of substrate in the flight muscles. The volume of the tracheal system of F. mannifera is about 45% of total body volume. At rest, FCC2 in the thoracic air sacs remains near 17% and FCOCO2, near 3%. During non-flapping warm-up, FOO2 falls to as low as 1 and FCOCO2 rises to as high as 21%. Thus, gas exchange may limit the rate warm-up. When wing-flapping commences, FOO2 and FCOCO2 quickly return near resting levels, presumably as a result of auto ventilation. The interspecific regression of VOO2 on mass for three species of cicadas 23–24°C has a slope of 0.89 and a 1-g intercept of 0.63 mlh

    The Ursinus Weekly, February 6, 1922

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    Woman lecturer commands attention • Juniata wins from \u27sinus in hard fought battle • Scrubs lose to local high school • Ursinus loses to Villanova by one point • Varsity in cage duel humbles Swarthmore • College gives third pastor to Thornville, Ohio, charge • Open forum meeting postponed • January dance social success • Boiler house wall falls at night • The ministry of today • Athletic committee appoints Snyder as acting basketball manager • Reserves lose to Bethlehem Prep. and Nazareth High School over week-end • New students • Olevianites entertainhttps://digitalcommons.ursinus.edu/weekly/2407/thumbnail.jp

    Effects of activity and temperature on aerobic and anaerobic metabolism in the Galapagos marine iguana

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    1 Standard and maximal levels of oxygen consumption, and lactate production during burst activity were determined in the Galapagos marine iguana, Amblyrhynchus cristatus . This semiaquatic lizard sustains vigorous activity at relatively low body temperatures during underwater feeding (<25°C).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47117/1/360_2004_Article_BF00691052.pd

    Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

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    <p>Abstract</p> <p>Background</p> <p>Severe anaemia (SA), intravascular haemolysis (IVH) and respiratory distress (RD) are severe forms of <it>Plasmodium falciparum </it>malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism leading to excess anaemia in acute <it>P. falciparum </it>infection.</p> <p>Methods</p> <p>The direct Coombs test (DCT) and flow cytometry were used to investigate the mean levels of RBC-bound complement fragments (C3d and C3bαβ) and the regulatory proteins [complement receptor 1 (CD35) and decay accelerating factor (CD55)] in children with discrete clinical forms of <it>P. falciparum </it>malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb) levels and RD were investigated.</p> <p>Results</p> <p>Of the 484 samples tested, 131(27%) were positive in DCT, out of which 115/131 (87.8%) were positive for C3d alone while 16/131 (12.2%) were positive for either IgG alone or both. 67.4% of the study population were below 5 years of age and DCT positivity was more common in this age group relative to children who were 5 years or older (Odds ratio, OR = 3.8; 95%CI, 2.2–6.7, p < 0.001). DCT correlated significantly with RD (β = -304, p = 0.006), but multiple regression analysis revealed that, Hb (β = -0.341, p = 0.012) and coma (β = -0.256, p = 0.034) were stronger predictors of RD than DCT (β = 0.228, p = 0.061). DCT was also not associated with IVH, p = 0.19, while spleen size was inversely correlated with Hb (r = -402, p = 0.001). Flow cytometry showed similar mean fluorescent intensity (MFI) values of CD35, CD55 and C3bαβ levels on the surfaces of RBC in patients and asymptomatic controls (AC). However, binding of C3bαβ correlated significantly with CD35 or CD55 (p < 0.001).</p> <p>Conclusion</p> <p>These results suggest that complement activation contributed to anaemia in acute childhood <it>P. falciparum </it>malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement regulatory proteins, CD35 and CD55 and malarial anaemia. These findings suggest that complement activation could also be involved in the pathogenesis of RD but larger studies are needed to confirm this finding.</p

    A mediation approach to understanding socio-economic inequalities in maternal health-seeking behaviours in Egypt.

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    BACKGROUND: The levels and origins of socio-economic inequalities in health-seeking behaviours in Egypt are poorly understood. This paper assesses the levels of health-seeking behaviours related to maternal care (antenatal care [ANC] and facility delivery) and their accumulation during pregnancy and childbirth. Secondly, it explores the mechanisms underlying the association between socio-economic position (SEP) and maternal health-seeking behaviours. Thirdly, it examines the effectiveness of targeting of free public ANC and delivery care. METHODS: Data from the 2008 Demographic and Health Survey were used to capture two latent constructs of SEP: individual socio-cultural capital and household-level economic capital. These variables were entered into an adjusted mediation model, predicting twelve dimensions of maternal health-seeking; including any ANC, private ANC, first ANC visit in first trimester, regular ANC (four or more visits during pregnancy), facility delivery, and private delivery. ANC and delivery care costs were examined separately by provider type (public or private). RESULTS: While 74.2% of women with a birth in the 5-year recall period obtained any ANC and 72.4% delivered in a facility, only 48.8% obtained the complete maternal care package (timely and regular facility-based ANC as well as facility delivery) for their most recent live birth. Both socio-cultural capital and economic capital were independently positively associated with receiving any ANC and delivering in a facility. The strongest direct effect of socio-cultural capital was seen in models predicting private provider use of both ANC and delivery. Despite substantial proportions of women using public providers reporting receipt of free care (ANC: 38%, delivery: 24%), this free-of-charge public care was not effectively targeted to women with lowest economic resources. CONCLUSIONS: Socio-cultural capital is the primary mechanism leading to inequalities in maternal health-seeking in Egypt. Future studies should therefore examine the objective and perceived quality of care from different types of providers. Improvements in the targeting of free public care could help reduce the existing SEP-based inequalities in maternal care coverage in the short term

    Thermoregulation and heterothermy in some of the smaller flying foxes (Megachiroptera) of New Guinea

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    Body temperature, heterothermy, oxygen consumption, heart rate, and evaporative water loss were studied in four species of flying foxes (Megachiroptera), Dobsonia minor, Nyctimene major, Nyctimene albiventer , and Paranyctimene raptor , from the vicinity of Madang on the north coast of New Guinea.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47105/1/359_2004_Article_BF00297716.pd

    Insights into deregulated TNF and IL-10 production in malaria: implications for understanding severe malarial anaemia

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    BACKGROUND: Severe malarial anaemia (SMA) is a major life-threatening complication of paediatric malaria. Protracted production of pro-inflammatory cytokines promoting erythrophagocytosis and depressing erythropoiesis is thought to play an important role in SMA, which is characterized by a high TNF/IL-10 ratio. Whether this TNF/IL-10 imbalance results from an intrinsic incapacity of SMA patients to produce IL-10 or from an IL-10 unresponsiveness to infection is unknown. Monocytes and T cells are recognized as the main sources of TNF and IL-10 in vivo, but little is known about the activation status of those cells in SMA patients. METHODS: The IL-10 and TNF production capacity and the activation phenotype of monocytes and T cells were compared in samples collected from 332 Ghanaian children with non-overlapping SMA (n = 108), cerebral malaria (CM) (n = 144) or uncomplicated malaria (UM) (n = 80) syndromes. Activation status of monocytes and T cells was ascertained by measuring HLA-DR(+) and/or CD69(+) surface expression by flow cytometry. The TNF and IL-10 production was assessed in a whole-blood assay after or not stimulation with lipopolysaccharide (LPS) or phytohaemaglutinin (PHA) used as surrogate of unspecific monocyte and T cell stimulant. The number of circulating pigmented monocytes was also determined. RESULTS: Monocytes and T cells from SMA and CM patients showed similar activation profiles with a comparable decreased HLA-DR expression on monocytes and increased frequency of CD69(+) and HLA-DR(+) T cells. In contrast, the acute-phase IL-10 production was markedly decreased in SMA compared to CM (P = .003) and UM (P = .004). Although in SMA the IL-10 response to LPS-stimulation was larger in amplitude than in CM (P = .0082), the absolute levels of IL-10 reached were lower (P = .013). Both the amplitude and levels of TNF produced in response to LPS-stimulation were larger in SMA than CM (P = .019). In response to PHA-stimulation, absolute levels of IL-10 produced in SMA were lower than in CM (P = .005) contrasting with TNF levels, which were higher (P = .001). CONCLUSIONS: These data reveal that SMA patients have the potential to mount efficient IL-10 responses and that the TNF/IL-10 imbalance may reflect a specific monocyte and T cell programming/polarization pattern in response to infection

    Small Area Estimation of Latent Economic Well-being

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    Š The Author(s) 2019. Small area estimation (SAE) plays a crucial role in the social sciences due to the growing need for reliable and accurate estimates for small domains. In the study of well-being, for example, policy makers need detailed information about the geographical distribution of a range of social indicators. We investigate data dimensionality reduction using factor analysis models and implement SAE on the factor scores under the empirical best linear unbiased prediction approach. We contrast this approach with the standard approach of providing a dashboard of indicators or a weighted average of indicators at the local level. We demonstrate the approach in a simulation study and a real data application based on the European Union Statistics for Income and Living Conditions for the municipalities of Tuscany

    An Evaluation of the Precision of Measurement of Ryff’s Psychological Well-Being Scales in a Population Sample

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    The aim of this study is to assess the effective measurement range of Ryff’s Psychological Well-being scales (PWB). It applies normal ogive item response theory (IRT) methodology using factor analysis procedures for ordinal data based on a limited information estimation approach. The data come from a sample of 1,179 women participating in a midlife follow-up of a national birth cohort study in the UK. The PWB scales incorporate six dimensions: autonomy, positive relations with others, environmental mastery, personal growth, purpose in life and self-acceptance. Scale information functions were calculated to derive standard errors of measurement for estimated scores on each dimension. Construct variance was distinguished from method variance by inclusion of method factors from item wording (positive versus negative). Our IRT analysis revealed that the PWB measures well-being most accurately in the middle range of the score distribution, i.e. for women with average well-being. Score precision diminished at higher levels of well-being, and low well-being was measured more reliably than high well-being. A second-order well-being factor loaded by four of the dimensions achieved higher measurement precision and greater score accuracy across a wider range than any individual dimension. Future development of well-being scales should be designed to include items that are able to discriminate at high levels of well-being
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