939 resultados para In-stream structures
Resumo:
The latest results from the study paint a picture of how these families are faring across a range of areas in their lives including their health, family life and financial and economic circumstances. In general the findings show that three-year-olds in Ireland are in good health with a few notable public health and related issues (including overweight and obesity), there is overall stability in family structures over the short term and that the recession has had a substantial effect on families with young children over the last number of years. These are the first longitudinal findings from the study. The first wave of fieldwork with the families of the Infant Cohort included approximately 11,100 nine-month-olds, their parents and carers. Interviews began in September 2008 and were completed in March 2009. Interviews for the second round of interviews with this cohort took place between January and August 2011. A total of 90% of the original sample of nine-month-olds were successfully re-interviewed. (A full download of the results released today, presented in three briefing documents can be found by clicking here. Key findings include: Health â?¢ Most of the children were described as being in good health; 75% were rated as very healthy and a further 23% were rated as healthy, but a few minor problems. Girls were more likely to be reported as very healthy (78%) compared with boys (72%). â?¢ One in four or almost one quarter of three-year-old children were overweight (19%) or obese (6%). â?¢ Childrenâ?Ts weight was related to household social class. 5% of children in families in the professional/managerial group were classified as obese at three years of age compared with 9% of those in the most disadvantaged social class group. However, at least one-fifth of children in every social class were overweight. â?¢ Childrens consumption of energy-dense foods such as crisps, sweets, chips, and non-diet fizzy drinks increased as parental education fell. 63% of children whose mother had a lower secondary education or less ate at least one portion of crisps compared with 36% of those from degree-level backgrounds, although consumption of biscuits/chocolates was over 70% for both groups of children. â?¢ Two-thirds (66%) of three-year-olds had received at least one course of antibiotics in the 12 months preceding the interview. Children with a full medical card (35% of the sample) or a GP-only medical card (5% of the sample) were more likely to have received a course of antibiotics than â?¢ Children with a full medical card received a higher number of antibiotic courses on average (2.6) compared with those without a medical card (2.1). â?¢ Just under 16% of three-year-old children were reported as having at least one longstanding illness, condition or disability. The most commonly reported illness types included Asthma (5.8%), Eczema/Skin allergies (3.9%) and Food/digestive allergies (1.2%) Family Life and Childcare â?¢ While the overall distribution of family structure was stable, there have been transitions from one-parent families to two-parent families and vice-versa over the 27 months between interview â?" approximately 2 to 3 percent in each direction. â?¢ 50% of three year olds were in some form of non-parental childcare for eight or more hours a week. The most common form used was centre-based childcare which almost tripled between nine months and three years, from 11% to 30%. â?¢ A similar percentage of grandparents were caring for children at both nine months and three years, 12% and 11% respectively. A total of 10% of three-year-olds were being minded by a childminder, an increase of 3 percentage points from when the children were nine months of age. â?¢ Children who were in some form of non-parental childcare were spending an average of 23 hours a week in their main type of childcare. â?¢ At time of interview the vast majority of mothers reported that they had regular contact with the Study Childâ?Ts grandparents (91%). In offering support to parents, grandparents were most likely to babysit (50%), and buy clothes (40%) at least on a monthly basis. One-parent families were more likely than two-parent families to receive financial support from grandparents with just under one-third (66%) of one-parent families receiving financial support from grandparents at least once every three months. â?¢ The most frequently used discipline technique was â?~discussing or explaining why the behaviour was wrongâ?T, with 63% of mothers saying they always did this. â?¢ 12% of mothers said they used â?~smackingâ?T as a form of discipline now and again and less than 1% used â?~smackingâ?T as a form of discipline more frequently. Over half reported that they never smacked the Study Child. Financial and Economic Circumstances â?¢ Just over half (53%) of mothers of three-year-olds worked outside the home, 38% said they were on home duties and 6% said they were unemployed. â?¢ The biggest change in terms of the work status of three-year-oldsâ?T parents was an increase in the percentage of unemployed fathers â?" 6% when the child was nine months rising to almost 14% when s/he was three years of age. â?¢ 61% of families of three-year-olds reported experiencing difficulties in making â?~ends meetâ?T. This was a substantial increase from 44% in the first round of interviews when the children were nine-months-old. â?¢ Almost two thirds (63%) of all families with three-year-olds reported that the recession had had a very significant or significant effect on them. â?¢ The most frequently recorded effects were: a reduction in wages (63%); canâ?Tt afford luxuries (54%), social welfare reduction (53%) and canâ?Tt afford/cut back on basics (32%). Growing Up in Ireland is a Government funded study tracking the development of two nationally representative cohorts of children: an Infant Cohort which was interviewed initially at nine months and subsequently at three years of age; and a Child Cohort which was interviewed initially at nine years and subsequently at 13 years of age. The study is being conducted by a consortium of researchers led by the Economic and Social Research Institute (ESRI) and Trinity College Dublin. For Further Information Please Contact: Jillian Heffernan Communications Officer, Growing Up in Ireland Tel: 01 896 3378 Mobile: 087 9016880This resource was contributed to our repository by the National Documentation Centre on Drug Use.
Resumo:
An important activity of mucosal surfaces is the production of antibodies (Abs) referred to as secretory immunoglobulin A (SIgA) that serve as a first line of defense to repel pathogenic microorganisms and provide a finely tuned balance to guarantee controlled survival of essential commensal bacteria. By excluding bacteria from the epithelial cell, SIgA participates in the cross-talk between the host and its intestinal content, ensuring appropriate homeostasis under normal conditions. Besides the classical view of immune exclusion function, SIgA Abs exhibit the striking feature to adhere to gastrointestinal M cells residing in the follicle-associated epithelium in organized structures called Peyer's patches. Selective binding of SIgA results in transport across the microfold (M) cells, a process that facilitates the association of the Ab with dendritic cells (DCs) located in the underlying subepithelial dome region of Peyer's patches. Limited entry of free SIgA and SIgA-coated bacteria via this pathway is crucial to the modulation of local immune responses in an environment that limits the onset of pro-inflammatory circuits. Such a mechanism would ensure homeostasis by allowing antigen recognition under neutralized conditions and by avoiding tissue dissemination, two features that endow SIgA with non-inflammatory properties in the mucosal environment.
Resumo:
The preclinical Alzheimer's disease (AD) - amnestic mild cognitive impairment (MCI) - is manifested by phenotypes classified into exclusively memory (single-domain) MCI (sMCI) and multiple-domain MCI (mMCI). We suggest that typical MCI-to-AD progression occurs through the sMCI-to-mMCI sequence as a result of the extension of initial pathological processes. To support this hypothesis, we assess myelin content with a Magnetization Transfer Ratio (MTR) in 21 sMCI and 21 mMCI patients and in 42 age-, sex-, and education-matched controls. A conjunction analysis revealed MTR reduction shared by sMCI and mMCI groups in the medial temporal lobe and posterior structures including white matter (WM: splenium, posterior corona radiata) and gray matter (GM: hippocampus; parahippocampal and lingual gyri). A disjunction analysis showed the spread of demyelination to prefrontal WM and insula GM in executive mMCI. Our findings suggest that demyelination starts in the structures affected by neurofibrillary pathology; its presence correlates with the clinical picture and indicates the method of MCI-to-AD progression. In vivo staging of preclinical AD can be developed in terms of WM/GM demyelination.
Resumo:
Several evidences suggest that astrocytes release small transmitter molecules, peptides, and protein factors via regulated exocytosis, implying that they function as specialized neurosecretory cells. However, very little is known about the molecular and functional properties of regulated secretion in astrocytes in the adult brain. Establishing these properties is central to the understanding of the communication mode(s) of these cells and their role(s) in the control of synaptic functions and of cerebral blood flow. In this study, we have set-up a high-resolution confocal microscopy approach to distinguish protein expression in astrocytic structures and neighboring synaptic terminals in adult brain tissue. This approach was applied to investigate the expression pattern of core SNARE proteins for vesicle fusion in the dentate gyrus and CA1 regions of the mouse hippocampus. Our comparative analysis shows that astrocytes abundantly express, in their cell body and main processes, all three protein partners necessary to form an operational SNARE complex but not in the same isoforms expressed in neighbouring synaptic terminals. Thus, SNAP25 and VAMP2 are absent from astrocytic processes and typically concentrated in terminals, while SNAP23 and VAMP3 have the opposite expression pattern. Syntaxin 1 is present in both synaptic terminals and astrocytes. These data support the view that astrocytes in the adult hippocampus can communicate via regulated exocytosis and also indicates that astrocytic exocytosis may differ in its properties from action potential-dependent exocytosis at neuronal synapses, as it relies on a distinctive set of SNARE proteins.
Resumo:
Gastrointestinal stromal tumours (GIST), despite being rare, pose a relevant medical problem from the viewpoint of diagnosis and management. GIST are fragile, liable to metastasize and often located in delicate structures. Surgical options, therefore, are limited. In the last decade an improved understanding of the molecular mechanisms of the disease has resulted in novel modes of treatment. The introduction of systemic tyrosine kinase inhibitor therapy with imatinib has significantly improved the outcome of the disease and prolonged the survival of GIST patients. For many patients the acute threat of a deadly cancer has been transformed into a manageable chronic condition. Drug safety, tolerability and compliance, subjects of concern in all long-term therapies, have proven to be acceptable for the tyrosine kinase inhibitor imatinib. The present paper provides a compact overview of the epidemiology, pathophysiology and morphology of GIST, with special reference to the underlying molecular biology. Relevant aspects of diagnosis, therapy and monitoring of the disease are reviewed with particular emphasis on the available clinical evidence and recent guidelines.
Resumo:
During the postnatal development of cat visual cortex and corpus callosum the molecular composition of tau proteins varied with age. In both structures, they changed between postnatal days 19 and 39 from a set of two juvenile forms to a set of at least two adult variants with higher molecular weights. During the first postnatal week, tau proteins were detectable with TAU-1 antibody in axons of corpus callosum and visual cortex, and in some perikarya and dendrites in the visual cortex. At later ages, tau proteins were located exclusively within axons in all cortical layers and in the corpus callosum. Dephosphorylation of postnatal day 11 cortical tissue by alkaline phosphatase strongly increased tau protein immunoreactivity on Western blots and in numerous perikarya and dendrites in all cortical layers, in sections, suggesting that some tau forms had been unmasked. During postnatal development the intensity of this phosphate-dependent somatodendritic staining decreased, but remained in a few neurons in cortical layers II and III. On blots, the immunoreactivity of adult tau to TAU-1 was only marginally increased by dephosphorylation. Other tau antibodies (TAU-2, B19 and BR133) recognized two juvenile and two adult cat tau proteins on blots, and localized tau in axons or perikarya and dendrites in tissue untreated with alkaline phosphatase. Tau proteins in mature tissue were soluble and not associated with detergent-resistant structures. Furthermore, dephosphorylation by alkaline phosphatase resulted in the appearance of more tau proteins in soluble fractions. Therefore tau proteins seem to alter their degree of phosphorylation during development. This could affect microtubule stability as well as influence axonal and dendritic differentiation.
Resumo:
Background: Alternatively spliced exons play an important role in the diversification of gene function in most metazoans and are highly regulated by conserved motifs in exons and introns. Two contradicting properties have been associated to evolutionary conserved alternative exons: higher sequence conservation and higher rate of non-synonymous substitutions, relative to constitutive exons. In order to clarify this issue, we have performed an analysis of the evolution of alternative and constitutive exons, using a large set of protein coding exons conserved between human and mouse and taking into account the conservation of the transcript exonic structure. Further, we have also defined a measure of the variation of the arrangement of exonic splicing enhancers (ESE-conservation score) to study the evolution of splicing regulatory sequences. We have used this measure to correlate the changes in the arrangement of ESEs with the divergence of exon and intron sequences. Results: We find evidence for a relation between the lack of conservation of the exonic structure and the weakening of the sequence evolutionary constraints in alternative and constitutive exons. Exons in transcripts with non-conserved exonic structures have higher synonymous (dS) and non-synonymous (dN) substitution rates than exons in conserved structures. Moreover, alternative exons in transcripts with non-conserved exonic structure are the least constrained in sequence evolution, and at high EST-inclusion levels they are found to be very similar to constitutive exons, whereas alternative exons in transcripts with conserved exonic structure have a dS significantly lower than average at all EST-inclusion levels. We also find higher conservation in the arrangement of ESEs in constitutive exons compared to alternative ones. Additionally, the sequence conservation at flanking introns remains constant for constitutive exons at all ESE-conservation values, but increases for alternative exons at high ESE-conservation values. Conclusion: We conclude that most of the differences in dN observed between alternative and constitutive exons can be explained by the conservation of the transcript exonic structure. Low dS values are more characteristic of alternative exons with conserved exonic structure, but not of those with non-conserved exonic structure. Additionally, constitutive exons are characterized by a higher conservation in the arrangement of ESEs, and alternative exons with an ESE-conservation similar to that of constitutive exons are characterized by a conservation of the flanking intron sequences higher than average, indicating the presence of more intronic regulatory signals.
Resumo:
Nyssomyia intermedia (Lutz & Neiva) and Nyssomyia neivai (Pinto) are morphologically very close and both present great variation in some structures. The objective of this study is a description of the variation among the females of these species in populations from the States of Minas Gerais and São Paulo. The morphological structures studied were the number of horizontal teeth in the cibarium and the number of rings and the shape of the terminal knob of the spermathecae. The spermatheca rings are significantly more numerous in N. intermedia than in N. neivai and the simple shape of the terminal knob predominated in both species. Regarding the cibarium, eight to eleven teeth have been found in both species, with up to twelve teeth in the latter. The number of horizontal teeth and the shape of the terminal knob of the spermathecae were variable throughout the populations of both species and all structures were polymorphic in the populations studied.
Resumo:
The following main lithostratigraphic units have been distinguished in the Domes Area. The Kibaran basement complex composed of gneisses, migmatites with amphibolite bands and metagranites is exposed in dome structures; metamorphic features of Kibaran age have been almost completely obliterated by extensive Lufilian reactivation. The post-Kibaran cover sequence is subdivided into the Lower Roan Group consisting of well-preserved quartzites with high Mg content, talc-bearing, extremely foliated schists intercalated with pseudo-conglomerates of tectonic origin and the Upper Roan Group including dolomitic marbles with rare stromatolites, metapelites and a sequence of detrital metasediments, with local volcano-sedimentary components and interlayered banded ironstones. The sediments of the Lower Roan Group are interpreted as continental to lagoonal-evaporitic deposits partly converted into the talc-kyanite + garnet assemblage characteristic of ``white schists''. The dolomites and metapelites of the Upper Roan Group are attributed to a carbonate platform sequence progressively subsiding under terrigenous deposits, whilst the detrital metasediments and BIF may be interpreted as a basinal sequence, probably deposited on oceanic crust grading laterally into marbles. Metagabbros and metabasalts are considered as remnants of an ocean-floor-type crustal unit probably related to small basins. Alkaline stocks of Silurian age intruded the post-Kibaran cover. Significant ancestral tectonic discontinuities promoted the development of a nappe pile that underwent high-pressure metamorphism during the Lufilian orogeny and all lithostratigraphic units. Rb-Sr and K-Ar and U-Pb data indicate an age of 700 Ma for the highest grade metamorphism and 500 Ma for blocking of the K-Ar and Rb-Sr system in micas, corresponding to the time when the temperature dropped below 350-degrees-400-degrees-C and to an age of about 400 Ma for the emplacement of hypabyssal syenitic bodies. A first phase of crustal shortening by decoupling of basement and cover slices along shallow shear zones has been recognized. Fluid-rich tectonic slabs of cover sediments were thus able to transport fluids into the anhydrous metamorphic basement or mafic units. During the subsequent metamorphic re-equilibration stage of high pressure, pre-existing thrusts horizons were converted into recrystallized mylonites. Due to uplift, rocks were re-equilibrated into assemblages compatible with lower pressures and slightly lower temperatures. This stage occurs under a decompressional (nearly adiabatic) regime, with P(fluid) almost-equal-to P(lithostatic). It is accompanied by metasomatic development of minerals, activated by injection of hot fluids. New or reactivated shear zones and mylonitic belts were the preferred conduits of fluids. The most evident regional-scale effect of these processes is the intense metasomatic scapolitization of formerly plagioclase-rich lithologies. Uraninite mineralization can probably be assigned to the beginning of the decompressional stage. A third regional deformation phase characterized by open folds and local foliation is not accompanied by significant growth of new minerals. However, pitchblende mineralization can be ascribed to this phase as late-stage, short-range remobilization of previously existing deposits. Finally, shallow alkaline massifs were emplaced when the level of the Domes Area now exposed was already subjected to exchange with meteoric circuits, activated by residual geothermal gradients generally related to intrusions or rifting. Most of the superficial U-showings with U-oxidation products were probably generated during this relatively recent phase.
Resumo:
Intensification of agricultural production without a sound management and regulations can lead to severe environmental problems, as in Western Santa Catarina State, Brazil, where intensive swine production has caused large accumulations of manure and consequently water pollution. Natural resource scientists are asked by decision-makers for advice on management and regulatory decisions. Distributed environmental models are useful tools, since they can be used to explore consequences of various management practices. However, in many areas of the world, quantitative data for model calibration and validation are lacking. The data-intensive distributed environmental model AgNPS was applied in a data-poor environment, the upper catchment (2,520 ha) of the Ariranhazinho River, near the city of Seara, in Santa Catarina State. Steps included data preparation, cell size selection, sensitivity analysis, model calibration and application to different management scenarios. The model was calibrated based on a best guess for model parameters and on a pragmatic sensitivity analysis. The parameters were adjusted to match model outputs (runoff volume, peak runoff rate and sediment concentration) closely with the sparse observed data. A modelling grid cell resolution of 150 m adduced appropriate and computer-fit results. The rainfall runoff response of the AgNPS model was calibrated using three separate rainfall ranges (< 25, 25-60, > 60 mm). Predicted sediment concentrations were consistently six to ten times higher than observed, probably due to sediment trapping along vegetated channel banks. Predicted N and P concentrations in stream water ranged from just below to well above regulatory norms. Expert knowledge of the area, in addition to experience reported in the literature, was able to compensate in part for limited calibration data. Several scenarios (actual, recommended and excessive manure applications, and point source pollution from swine operations) could be compared by the model, using a relative ranking rather than quantitative predictions.
Resumo:
Most of the large firms organization schemes consist in hierarchical structures of tiers with different wage levels. Traditionally the existence of this kind of organizations has been associated to the separation of productive and managerial or supervision tasks and to differences in the skills of the workers. However, many firms now employ workers with similar skills, and then the hierarchical structure can be related to an incentive scheme to ensure that workers supply effort. The model we present investigates how firm owners should determine the optimal wage distribution in order to maximize profits.
Resumo:
Most of the large firms organization schemes consist in hierarchical structures of tiers with different wage levels. Traditionally the existence of this kind of organizations has been associated to the separation of productive and managerial or supervision tasks and to differences in the skills of the workers. However, many firms now employ workers with similar skills, and then the hierarchical structure can be related to an incentive scheme to ensure that workers supply effort. The model we present investigates how firm owners should determine the optimal wage distribution in order to maximize profits.
Resumo:
In the present study, we searched for genes highly expressed in placenta and that could contribute to the establishment and maintenance of a malignant phenotype in different types of tumours, and in astrocytomas in particular. We employed a strategy based on the integration of in silico data from previously generated massively parallel signature sequencing and public serial analysis of gene expression databases. Among 12 selected genes, CD99 exhibited the highest relative mRNA expression in GBM compared to non-neoplastic brain tissues. In a larger cohort of astrocytic tumours, we further demonstrated increased CD99 expression in all malignant grades, with GBMs showing the highest values. These findings were confirmed at the protein level by Western blotting and immunohistochemistry. Additionally, we demonstrated the CD99 localisation profile in astrocytic tumours. Interestingly, CD99 expression was confined to the cytoplasm or membrane in more malignant astrocytomas, in contrast to non-neoplastic brain tissue or non-infiltrative pilocytic astrocytoma, which showed no obvious staining in these structures. Comparison of three GBM cell lines revealed higher CD99 expression at the membrane and higher migratory capacity in the A172 and U87MG lines, but lower CD99 expression and no migratory ability in the T98 line. Knocking down CD99 expression by siRNA decreased significantly the migration of both cell lines. These integrated CD99 gene and protein expression results suggest that CD99 expression in astrocytomas of different malignant grades might contribute to the infiltrative ability and support the importance of CD99 as a potential target to reduce infiltrative astrocytoma capacity in migration and invasion.
Resumo:
Abstract. Drought leads to a loss of longitudinal and lateral hydrologic connectivity, which causes direct or indirect changes in stream ecosystem properties. Changes in macrohabitat availability from a rifflepool sequence to isolated pools are among the most conspicuous consequences of connectivity loss. Macroinvertebrate assemblages were compared among 3 distinct stream macrohabitats (riffles [R], pools connected to riffles [Pc], disconnected pools [Pd]) of 19 Mediterranean-climate sites in northern California to examine the influence of loss of habitat resulting from drought disturbance. At the time of sampling, 10 sites were perennial and included R and Pc macrohabitats, whereas 9 sites were intermittent and included only Pd macrohabitats. Taxa richness was more variable in Pd, and taxa richness was significantly lower in Pd than in Pc but not R. These results suggested a decline in richness between Pc and Pd that might be associated with loss of connectivity. Lower Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness relative to Odonata, Coleoptera, and Heteroptera (OCH) richness was observed for Pd than R and Pc macrohabitats. Family composition was more similar between R and Pc than between R or Pc and Pd macrohabitats. This similarity may be associated with greater connectivity between R and Pc macrohabitats. Correspondence analysis indicated that macroinvertebrate composition changed along a gradient from R to Pc and Pd that was related to a perennialintermittent gradient across sites. High variability among macroinvertebrate assemblages in Pd could have been related to variability in the duration of intermittency. In cluster analysis, macroinvertebrate assemblages were grouped by macrohabitat first and then by site, suggesting that the macrohabitat filter had a greater influence on macroinvertebrate assemblages than did local site characteristics. Few taxa were found exclusively in Pc, and this macrohabitat shared numerous taxa with R and Pd, indicating that Pc may act as a bridge between R and Pd during drought. Drought is regarded as a ramp disturbance, but our results suggest that the response of macroinvertebrate assemblages to the loss of hydrological connectivity among macrohabitats is gradual, at least in Mediterranean-climate streams where drying is gradual. However, the changes may be more dramatic in arid and semiarid streams or in Mediterranean-climate streams if drying is rapid.
Resumo:
Micro-electromechanical systems (MEMS) provide vast improvements over existing sensing methods in the context of structural health monitoring (SHM) of highway infrastructure systems, including improved system reliability, improved longevity and enhanced system performance, improved safety against natural hazards and vibrations, and a reduction in life cycle cost in both operating and maintaining the infrastructure. Advancements in MEMS technology and wireless sensor networks provide opportunities for long-term continuous, real-time structural health monitoring of pavements and bridges at low cost within the context of sustainable infrastructure systems. The primary objective of this research was to investigate the use of MEMS in highway structures for health monitoring purposes. This study focused on investigating the use of MEMS and their potential applications in concrete through a comprehensive literature review, a vendor survey, and a laboratory study, as well as a small-scale field study. Based on the comprehensive literature review and vendor survey, the latest information available on off-the-shelf MEMS devices, as well as research prototypes, for bridge, pavement, and traffic applications were synthesized. A commercially-available wireless concrete monitoring system based on radio-frequency identification (RFID) technology and off-the-shelf temperature and humidity sensors were tested under controlled laboratory and field conditions. The test results validated the ability of the RFID wireless concrete monitoring system in accurately measuring the temperature both inside the laboratory and in the field under severe weather conditions. In consultation with the project technical advisory committee (TAC), the most relevant MEMS-based transportation infrastructure research applications to explore in the future were also highlighted and summarized.