265 research outputs found

    Relationships between phenotypic plasticity and environmental variables.

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    To understand the relations between environment and phenotypic plasticity is important to forecast any possible adaptation of plants to climate change. We tested for any difference between central and marginal (Mediterranean and Alpine). Study was performed on 20 populations chosen on the basis of their distance from niche optimum.In Mediterranean marginal populations : \u2022 wide flowers display corolla, \u2022 short stamen, inducing more investment in attractiveness than in seed maturation \u2022 lower pollen production and seed set. Our results suggestthat: Largest floral display and lowest allocation of resources for seeds production in Mediterranean populations may be due to the highest competition for resources (pollinators, water and soil nutrient) together with the lowest resource availability. Future climate change will probably bring about: extinction of low altitudes populations the upward shift of other

    The cytochrome chain of mitochondria exhibits variable H+/e− stoichiometry

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    AbstractA study is presented of the ←H+/e− stoichiometry for H+ pumping by the cytochrome chain in isolated rat liver mitochondria under level-flow and steady-state conditions. It is shown that the ←H+/e− stoichiometry for the cytochrome chain varies under the influence of the flow rate and transmembrane ΔμH+. The rate-dependence is shown to be associated with cytochrome c oxidase, whose ←H+/e− ratio varies from 0 to 1, whilst the ←H+/c− ratio for the span covered by cytochrome c reductase is invariably 2

    Results of the fifth international spectroradiometer comparison for improved solar spectral irradiance measurements and related impact on reference solar cell calibration

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    This paper reports on the results of the fifth spectral irradiance measurement intercomparison and the impact these results have on the spread of spectral mismatch calculations in the outdoor characterization of reference solar cell and photovoltaic (PV) devices. Ten laboratories and commercial partners with their own instruments were involved in the comparison. Solar spectral irradiance in clear sky condition was measured with both fast fixed and slow rotating grating spectroradiometers. This paper describes the intercomparison campaign, describes different statistical analysis used on acquired data, reports on the results, and analyzes the impact these results would have on the primary calibration of a c-Si PV reference cell under natural sunlight

    Wolfram Syndrome (Diabetes Insipidus, Diabetes, Optic Atrophy, and Deafness): Clinical and genetic study

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    OBJECTIVE—Wolfram syndrome is an autosomal recessive neurodegenerative disorder characterized by diabetes insipidus, diabetes (nonautoimmune), optic atrophy, and deafness (a set of conditions referred to as DIDMOAD). The WFS1 gene is located on the short arm of chromosome 4. Wolfram syndrome prevalence is 1 in 770,000 live births, with a 1 in 354 carrier frequency

    Maturity-Onset Diabetes of the Young in Children With Incidental Hyperglycemia:: A multicenter Italian study of 172 families

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    OBJECTIVE - To investigate the prevalence of maturity-onset diabetes of the young (MODY) in Italian children With incidental hyperglycemia. RESEARCH DESIGN AND METHODS - Among 748 subjects age 1-18 years with incidental hyperglycemia, minimal diagnostic criteria for MODY were met by 172 families. Mutational analyses of the glucokinase (GCK) and hepatocyte nuclear factor lot (HNF1A) genes were performed. RESULTS - We identified 85 GCK gene mutations in 109 probands and 10 HNF1A mutations in 12 probands. In GCK patients, the median neonatal weight and age at the first evaluation were lower than those found in patients with HNF1A mutations. Median fasting plasma glucose and impaired fasting glucose/impaired glucose tolerance frequency after oral glucose tolerance testing were higher in GCK patients, who also showed a lower frequency of diabetes than HNF1A patients. CONCLUSIONS - GCK mutations are the prevailing cause of MODY (63.4%) when the index case is recruited in Italian children with incidental hyperglycemia

    Insulin pump failures in Italian children with Type 1 diabetes: retrospective 1-year cohort study

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    AimsInsulin pump failure and/or malfunction requiring replacement have not been thoroughly investigated. This study evaluated pump replacement in children and adolescents with Type 1 diabetes using insulin pump therapy.MethodsData were collected for all participants younger than 19 years, starting insulin pump therapy before 31 December 2013. For each child, age, disease duration, date of insulin pump therapy initiation, insulin pump model, failure/malfunction/replacement yes/no and reason were considered for the year 2013.ResultsData were returned by 40 of 43 paediatric centres belonging to the Diabetes Study Group of the Italian Society of Paediatric Endocrinology and Diabetology. In total, 1574 of 11 311 (13.9%) children and adolescents with Type 1 diabetes were using an insulin pump: 29.2% Animas VIBE, 9.4% Medtronic MiniMed 715/515, 34.3% Medtronic MiniMed VEO, 24.3% Accu-Check Spirit Combo and 2.8% other models. In 2013, 0.165 insulin pump replacements per patient-year (11.8% due to pump failure/malfunction and 4.7% due to accidental damage) were recorded. Animas VIBE (22.1%) and Medtronic MiniMed VEO (17.7%) were the most replaced.ConclusionsIn a large cohort of Italian children and adolescents with Type 1 diabetes, insulin pump failure/malfunction and consequent replacement are aligned with rates previously reported and higher in more sophisticated pump models

    Age-Period-Cohort Analysis of 1990–2003 Incidence Time Trends of Childhood Diabetes in Italy: The RIDI Study

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    OBJECTIVE - To investigate age-period-cohort effects on the temporal trend of type 1 diabetes in children age 0-14 years in Italian registries. RESEARCH DESIGN AND METHODS - This report is based on 5,180 incident cases in the period 1990-2003 from the Registry for Type 1 Diabetes Mellitus in Italy (RIDI). Multilevel (random intercept) Poisson regression models were used to model the effects of sex, age, calendar time, and birth cohorts on temporal trends, taking into account the registry-level variance component. RESULTS - The incidence rate was 12.26 per 100,000 personyears and significantly higher in boys (13.13 [95% CI 12.66-13.62]) than in girls (11.35 [10.90-11.82]). Large geographical variations in incidence within Italy were evident; incidence was highest in Sardinia, intermediate in Central-Southern Italy, and high in Northern Italy, particularly in the Trento Province, where the incidence rate was 18.67 per 100,000 person-years. An increasing temporal trend was evident (2.94% per year [95% CI 2.22-3.67]). With respect to the calendar period 1990-1992, the incidence rates increased linearly by 15, 27, 35, and 40% in the following time periods (P for trend < 0.001). With respect to the 1987-1993 birth cohort, the incidence rate ratio increased approximately linearly from 0.63 (95% CI 0.54-0.73) in the 1975-1981 cohort to 1.38 (1.06-1.80) in the 1999-2003 cohort. The best model, however, included sex, age, and a linear time trend (drift). CONCLUSIONS - Large geographical variations and an increasing temporal trend in diabetes incidence are evident among type 1 diabetic children in Italy. Age-period-cohort analysis shows that the variation over time has a linear component that cannot be ascribed to either the calendar period or the birth cohort
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