Asymptotic properties for Volterra integro-dynamic systems

Using the resolvent matrix, a comparison principle and a useful equivalent system, we investigate the asymptotic behavior of linear Volterra integro-dynamic systems on time scales

β-cell dysfunctional ERAD/ubiquitin/proteasome system in type 2 diabetes mediated by islet amyloid polypeptide-induced UCH-L1 deficiency.

ObjectiveThe islet in type 2 diabetes is characterized by β-cell apoptosis, β-cell endoplasmic reticulum stress, and islet amyloid deposits derived from islet amyloid polypeptide (IAPP). Toxic oligomers of IAPP form intracellularly in β-cells in humans with type 2 diabetes, suggesting impaired clearance of misfolded proteins. In this study, we investigated whether human-IAPP (h-IAPP) disrupts the endoplasmic reticulum-associated degradation/ubiquitin/proteasome system.Research design and methodsWe used pancreatic tissue from humans with and without type 2 diabetes, isolated islets from h-IAPP transgenic rats, isolated human islets, and INS 832/13 cells transduced with adenoviruses expressing either h-IAPP or a comparable expression of rodent-IAPP. Immunofluorescence and Western blotting were used to detect polyubiquitinated proteins and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) protein levels. Proteasome activity was measured in isolated rat and human islets. UCH-L1 was knocked down by small-interfering RNA in INS 832/13 cells and apoptosis was evaluated.ResultsWe report accumulation of polyubiquinated proteins and UCH-L1 deficiency in β-cells of humans with type 2 diabetes. These findings were reproduced by expression of oligomeric h-IAPP but not soluble rat-IAPP. Downregulation of UCH-L1 expression and activity to reproduce that caused by h-IAPP in β-cells induced endoplasmic reticulum stress leading to apoptosis.ConclusionsOur results indicate that defective protein degradation in β-cells in type 2 diabetes can, at least in part, be attributed to misfolded h-IAPP leading to UCH-L1 deficiency, which in turn further compromises β-cell viability

Développement d’une nouvelle méthode de régionalisation basée sur le concept de « régime des débits naturels » : la méthode éco-géographique

Nous proposons une nouvelle méthode de régionalisation des débits fondée sur le concept de « régime des débits naturels » introduit en écologie aquatique : l’approche éco-géographique. Elle se distingue de deux approches de régionalisation existantes (approches hydrologique et écologique) sur les trois points suivants : le choix des variables hydrologiques, l’échelle d’analyse et la finalité de la régionalisation. En ce qui concerne le choix des variables hydrologiques, la nouvelle méthode est fondée sur le choix des caractéristiques des débits et non sur les variables hydrologiques. Ces caractéristiques des débits sont définies au moyen de l’analyse en composantes principales appliquée sur les variables hydrologiques. Contrairement aux autres approches, l’approche éco-géographique tient compte de toutes les caractéristiques des débits dans la régionalisation conformément au concept de « régime des débits naturels ». Quant à l’échelle d’analyse, à l’instar de l’approche écologique, la nouvelle méthode s’applique aussi à toutes les échelles d’analyse (annuelle, mensuelle et journalière) mais en les considérant séparément afin de tenir compte de toutes les caractéristiques de débits dans la régionalisation. Enfin, la finalité de la nouvelle méthode est de pouvoir déterminer les facteurs de variabilité spatiale des caractéristiques de débits (et non des variables hydrologiques) au moyen de l’analyse canonique des corrélations, notamment afin d’assurer une gestion durable des ressources hydriques dans un contexte de changement de l’environnement. Nous avons appliqué cette nouvelle méthode aux débits moyens annuels au Québec.Flow regionalization has been the subject of numerous hydrologic studies. However, despite the development of regionalization methods, there are still differences in the approaches used amongst hydrologists on the one hand, and between hydrologists and experts in other fields (aquatic ecology and physical geography) on the other hand. Those differences relate to five aspects of the regionalization process: the choice of hydrologic variables, station grouping methods to produce homogeneous hydrologic regions, the choice of appropriate statistical laws to estimate quantiles for non-gauged or partially-gauged sites, the scale of flow analysis, and the ultimate purpose of the regionalization exercise. Depending on the choice of hydrologic variables, the scale of analysis and their ultimate purpose, regionalization studies may thus be divided according to two distinct approaches: the hydrologic approach and the ecologic approach.The ultimate purpose of the hydrologic approach is to estimate flows at non-gauged or partially-gauged sites. For this reason, it has been primarily concerned with methods that allow the grouping of stations into homogeneous hydrologic regions and with the choice of statistical laws to estimate quantiles for non-gauged or partially-gauged sites. However, despite its undeniable interest from a practical point of view, this approach does not address the concerns of ecologists and geographers for three reasons: 1) the choice of hydrologic variables used for regionalization is not based on a scientific concept (this choice is arbitrary, and the variables selected do not constrain all the flow characteristics); 2) the ultimate purpose of the regionalization exercise is limited to estimating flows and is of limited interest to geographers and ecologists; 3) regionalization is performed at a daily scale, without taking into account other scales.To make up for these limitations, ecologists have recently proposed regionalization based on the “natural flow regime” concept (the ecologic approach), which allows all fundamental flow characteristics (magnitude, frequency, duration, timing of occurrence and variability) to be taken into account. The rationale for considering all flow characteristics is that each characteristic has an effect on the behaviour of river ecosystems. Hence, regionalization based on the ecologic approach relies on a large number of hydrologic variables that define the fundamental flow characteristics. Rather than being arbitrary, the choice of variable is based on this new paradigm. Regionalization using the ecologic approach considers all time scales, and its ultimate purpose is to account for differences in the structure and biological composition of aquatic ecosystems.However, one of the limitations of studies based on this approach is that, no matter how numerous they are, the variables used for regionalization do not constrain all flow characteristics, as required by the natural flow regime concept, so that application of this concept is incomplete. In addition, simultaneous analysis of all time scales does not allow consideration of all flow characteristics. To overcome these limitations, we propose a new regionalization approach based on the natural flow regime concept, an “ecogeographic” approach that differs from the ecologic approach in three ways. First, the proposed method is based on the use of flow characteristics rather than hydrologic variables. The reason for this is that there are an infinite number of hydrologic variables to define the five fundamental characteristics, making it impossible to account for all of them in the regionalization process. In contrast, since the number of fundamental flow characteristics is limited, they can all be taken into account, consistent with the “natural flow regime” requirements. Second, the ultimate purpose of the proposed regionalization method is to identify the physiographic and climatic factors that explain the spatial variability of these fundamental characteristics. To achieve this goal, it is necessary to analyze the different time scales (daily, monthly, annual) separately given the fact that it is impossible to constrain the effect of these various physiographic and climatic factors at all time scales. Indeed, some factors may show an effect at some time scales and not at others. This ultimate purpose addresses the concerns of geographers interested in explaining the spatial variability of such phenomena, among other things. Finally, separate analysis of the various time scales makes it possible to define all flow characteristics linked to a given time scale. As such, application of the “natural flow regime” concept to regionalization is complete.Application of the ecogeographical method involves four separate steps: 1) the definition of the flow characteristics for the hydrologic series of interest; 2) the determination of minor and major characteristics using principal component analysis, where a “major” flow characteristic is defined as one which meets the following criterion: TVE ≥ (100% / N), where N is the total number of characteristics that define the analyzed hydrologic series and TVE is the total variance explained; 3) the grouping of stations in homogeneous hydrologic regions based on factorial scores. Homogeneous hydrologic regions are divided in two types based on the presence or absence of stations: effective homogeneous regions contain stations whereas fictive homogenous regions do not; 4) the determination of the factors that affect the spatial variability of flow characteristics. This is achieved using canonical correlation analysis, an approach that we have applied to average annual flows in Quebec watersheds

Control of zootechnology leads to improved Cuttlefish (Sepia officinalis, L.) reproduction performance up to pre-industrial levels

Cephalopods are gaining momentum as an alternate group for aquaculture species diversification, not only because they are a good food source (highly appreciated in some worldwide markets) but they also have the potential to quickly reach a market size. However, there are some bottlenecks impeding the transition of culture technology from the laboratory to industry. One is related to control over reproduction in captivity. The objective of the present experiment was to verify the effects of tanks with different bottom areas/volumes on the reproduction performance of S. officinalis breeding stocks, when sex ratios were controlled a priori; and the food cost associated with such performance when individuals are fed a natural frozen diet. One hundred and ninety two juvenile cuttlefish were used to compare three different round-shaped tanks: one type with 3000L volume and two types with 9000L volume (with differences in bottom areas and water column). Individuals had their sex and maturity stage determined to establish a sexual ratio of 2 female:1 male per tank and assure that cuttlefish were still immature. Biological data was collected during both growth and reproduction stages and until the death of all females in each tank. The experiment lasted nearly 300 days. Temperature differences between tank types were registered during both stages. The optimizing of rearing conditions has allowed for higher growth and a higher amount of cuttlefish available for breeding purposes. A total of 123,751 eggs (in 85 batches) was obtained during this experiment, which is a number that may meet a small scale cuttlefish commercial hatchery facility requirements. The present conditions contributed to a better and predictable reproduction performance in specific 9000L tanks, with values reaching pre-industrial numbers (approximate to 24,000 eggs/tank). Moreover, both the amount of eggs per batch and the overall quality of eggs has increased. Three of these 9000L tanks have an overall consumption of approximate to 38.64 Kg tank(-1), which translates in an investment in feed of approximate to 193 (sic) tank(-1), 8.40 (sic) per cuttlefish and an overall daily tank expense of 1.76 (sic) d(-1).info:eu-repo/semantics/publishedVersio

Endocrine complications in patients of beta thalassemia major in a tertiary care hospital in Pakistan

OBJECTIVE: To determine the major endocrine complications present in patients of Thalassemia major presenting to a tertiary care center in Karachi, Pakistan. METHODS: Records of all thallasemia major patients at a Haematology Department in a tertiary care hospital of Karachi were retrospectively reviewed from May to August 2009 with specific focus on endocrine data and investigations. The patients\u27 data was recorded in a questionnaire and analyzed using SPSS v.17, frequencies and percentages along with corresponding 95% confidence interval were computed. RESULTS: Our data revealed that a significantly small percentage of those under care received regular endocrine follow-up. Male hypo-gonadal abnormalities had the highest probability; 100% of the tested patients had decreased levels of testosterone, while 95.2% had raised serum creatinine levels. Parathyroid dysfunction was noted in 40% of the patients. Of those screened 29.4% had blood glucose levels in the diabetic range and 11.8% of the tested patients had reduced levels of FT4. CONCLUSION: A high frequency at endocrine dysfunctions seen in thalasaemia patients included: male hypogonadism, parathyroid dysfunction, deranged blood glucose and FT4 levies

Prevalence of tobacco use among women: a cross sectional survey from a squatter settlement of Karachi, Pakistan

Background: While the prevalence of tobacco use has been slowly declining in the developed countries, rates have been steadily rising in the developing countries. This has led to a rapid rise in tobacco related lung diseases among women. Objective: Determine the prevalence of tobacco use (both smoking and smokeless) among women in an urban squatter settlement (Orangi Town) in Karachi, Pakistan. Methods: A cross-sectional survey was conducted on 19,325 females aged between 15 and 80 years in Orangi Town, an urban squatter settlement in Karachi, Pakistan. Modified questionnaire, developed by World Health Organization WHO and Global Adult Tobacco survey (GATS), was used in Urdu. A total of 16,987 women agreed to participate. Results: The mean age was 37.3 ± 9.8 years amongst whom 15,255 (89.80%) were married, 9143 (53.82%) admitted that at least one person uses tobacco in some form in their homes. The prevalence of smokeless tobacco was 42.25% (7178). The prevalence of smoking tobacco was low as compared to smokeless tobacco i.e. 18.0% (3058). Among smokers, 85.47% (1789) admitted that they had tried to quit smoking during last 12 months but failed. CONCLUSION: Tobacco use among women in an urban squatter settlement is very high and alarming. Preventive and control measures against tobacco use are required in these communities

Modes de variabilité temporelle des débits moyens annuels et leurs liens avec les indices climatiques au québec (canada)

La variabilité interannuelle des débits moyens annuels (1970-1995) de 70 stations hydrologiques réparties dans les trois grands bassins versants du Québec a été étudiée au moyen d’une analyse en composantes principales et d’un lissage par une moyenne mobile simple. Cinq modes de variabilité ont été ainsi identifiés selon la succession des phases de baisse et de hausse des débits. Les trois premiers modes caractérisent les rivières du bassin du fleuve Saint-Laurent. Le premier mode, qui regroupe le plus grand nombre de stations situées sur les deux rives du fleuve, montre une période de baisse des débits (avant 1980), suivie d’une longue phase de hausse modérée des débits. Ce mode est positivement corrélé à l’oscillation australe. Le second mode, qui regroupe les rivières situées au nord de la rive sud du Saint-Laurent, est caractérisé par des débits qui diminuent entre 1975 et 1985, puis augmentent. Il n’est corrélé à aucun indice climatique. Les stations qui forment le troisième mode sont principalement localisées en rive nord. Ce mode est caractérisé par deux phases de hausse séparées par une phase de baisse des débits. Certaines stations de ce mode sont corrélées aux oscillations arctique, australe et nord atlantique. Les deux derniers modes caractérisent les rivières situées au nord du 55e parallèle, dans les bassins de la Baie d’Ungava et de la Baie d’Hudson. Ces modes montrent une phase de diminution continue depuis la seconde période des années 1970 ou une phase de diminution précédée d’une longue phase normale des débits. Ils sont négativement corrélés à l’oscillation arctique et nord atlantique. Il se dégage de cette étude que la variabilité interannuelle des débits n’est pas synchrone à l’intérieur du bassin du fleuve Saint-Laurent.The temporal variability of the annual average discharges (1970-1995) of 70 hydrological stations distributed among Québec three main watersheds was studied by principal component analysis and smoothing by a simple moving average. Five temporal variability modes were thus identified according to the succession of decreasing and increasing discharge phases. The first three modes characterize rivers of the St. Lawrence watershed. The first mode, which includes the greatest number of stations located on both shores of the river, shows a period of decreasing discharges (before 1980), followed by a long phase of moderately increasing discharges. This mode is positively correlated with the Southern Oscillation. The second mode, which includes rivers located in the northern part of the south shore of the St. Lawrence, is characterized by discharges decreasing between 1975 and 1985 and then increasing. It is not correlated with any climate index. The stations forming the third mode are mainly located on the north shore. This mode is characterized by two increasing phases separated by a decreasing discharge phase. Some stations of this mode are correlated with the Arctic, Southern and North Atlantic Oscillations. The last two modes characterize rivers located north of the 55th parallel, in the Ungava Bay and Hudson Bay watersheds. These modes show a continuously decreasing phase since the second period of the 1970s or a decreasing phase preceded by a long normal discharge phase. They are negatively correlated with the Arctic and North Atlantic Oscillations. This study shows that the interannual discharge variability is not synchronous within the St. Lawrence River watershed