933 resultados para Existence and structure of the pullback attractor
Resumo:
In the north Atlantic subtropical gyre, the oceanic vertical structure of density is characterized by a region of rapid increase with depth. This layer is called the permanent pycnocline. The permanent pycnocline is found below a surface mode water ,which are ventilated every winter when penetrated locally by the mixed layer. Assessing the structure and variability of the permanent pycnocline is of a major interest in the understanding of the climate system because the pycnocline layer delimits important heat and anthropogenic reservoir. Moreover, the heat content structure translate into changes in the large scale stratification feature, such as the permanent pycnocline. We developed a new objective algorithm for the characterization of the large scale structure of the permanent pycnocline (OAC-P). Argo data have been used with OAC-P to provide a detailed description of the mean structure of the North-Atlantic subtropical pycnocline (e.g.: depth, thickness, temperature, salinity, density, potential vorticity). Results reveal a surprisingly complex structure with inhomogeneous properties. While the classical bowl shape of the pycnocline depth is captured, much more complex pycnocline structure emerges at the regional scale. In the southern recirculation gyre of the Gulf Stream Extension, the pycnocline is deep, thick, the maximum of stratification is found in the middle on the layer and follow an isopycnal surface. But local processes influence and modify this textbook description and the pycnocline is characterized by a vertically asymmetric structure and gradients in thermohaline properties. T/S distribution along the permanent pycnocline depth is complex and reveals a diversity of water masses resulting from mixing of different source waters. We will present the observed mean structure of the North-Atlantic subtropical permanent pycnocline and relate it to physical processes that constraint it.
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The marine diatom Haslea ostrearia produces a water-soluble blue-pigment named marennine of economic interest (e.g. in aquaculture for the greening of oysters). Up to date the studies devoted to ecological conditions under which this microalga develops never took into account the bacterial-H. ostrearia relationships. In this study the bacterial community was analysed by PCR-TTGE before and after H. ostrearia isolation cells recovered from 4 localities, to distinguish the relative part of the biotope and the biocenose and eventually to describe the temporal dynamic of the structure of the bacterial community. The bacterial structure of the phycosphere differed strongly from that of the bulk sediment. The similarity between bacteria recovered from the biofilm and the suspended bacteria did not exceed 10% (vs. > 90% amongst biofilms). The differences in genetic fingerprints, more especially high between two H. ostrearia isolates showed also the highest differences in the bacterial structure as the result of specific metabolomics profiles. The non-targeted metabolomic investigation showed that these profiles were more distinct in case of bacteria-alga associations than for the H. ostrearia monoculture. At the scale of a culture cycle in laboratory conditions, the bacterial community was specific to the growth stage. When H. ostrearia was subcultured for 9 months, a shift in the bacterial structure was shown from 3-months subculturing and the bacterial structure stabilized afterwards (70-86% similarities). A first insight of the relationships between H. ostrearia and its surrounding bacteria was shown for a better understanding of the ecological feature of this diatom.
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Cybercrime is a growing and worrisome problem, particularly when it involves minors. Cyber-aggression among adolescents in particular can result in negative legal and psychological consequences for people involved. Therefore, it is important to have instruments to detect these incidents early and understand the problem to propose effective measures for prevention and treatment. This paper aims to design a new self-report, the Cyber-Aggression Questionnaire for Adolescents (CYBA), to evaluate the extent to which the respondent conducts aggressions through a mobile phone or the internet and analyse the factorial and criterion validity and reliability of their scores in a sample of adolescents from Asturias, Spain. The CYBA was administered to 3,148 youth aged between 12 and 18 years old along with three self-reports to measure aggression at school, impulsivity, and empathy. Regarding factorial validity, the model that best represents the structure of the CYBA consists of three factors (Impersonation, Visual-sexual Cyber-aggression, and Verbal Cyber-aggression and Exclusion) and four additional indicators of Visual Cyber-aggression-Teasing/Happy Slapping. Regarding criterion validity, the score on the CYBA correlates positively with aggression at school and impulsivity and negatively with empathy. That is the way cyber-aggression correlates with these three variables, according to previous empirical evidence. The reliability of the scores on each item and factor of the CYBA are adequate. Therefore, the CYBA offers a valid and reliable measure of cyber-aggression in adolescents.
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Background and aims: A gluten-free diet is to date the only treatment available to celiac disease sufferers. However, systematic reviews indicate that, depending on the method of evaluation used, only 42% to 91% of patients adhere to the diet strictly. Transculturally adapted tools that evaluate adherence beyond simple self-informed questions or invasive analyses are, therefore, of importance. The aim is to obtain a Spanish transcultural adaption and validation of Leffler's Celiac Dietary Adherence Test. Methods: A two-stage observational transversal study: translation and back translation by four qualified translators followed by a validation stage in which the questionnaire was administered to 306 celiac disease patients aged between 12 and 72 years and resident in Aragon. Factorial structure, criteria validity and internal consistency were evaluated. Results: The Spanish version maintained the 7 items in a 3-factor structure. Feasibility was very high in all the questions answered and the floor and ceiling effects were very low (4.3% and 1%, respectively). The Spearman correlation with the self-efficacy and life quality scales and the self-informed question were statistically significant (p < 0.01). According to the questionnaire criteria, adherence was 72.3%. Conclusion: The Spanish version of the Celiac Dietary Adherence Test shows appropriate psychometric properties and is, therefore, suitable for studying adherence to a gluten-free diet in clinical and research environments.
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Child sexual abuse (CSA) disclosure is critical for survivor´s psychosocial adjustment later in life. The aim of the present study was to analyze the relationship between attributions of blame for child sexual abuse by the victim and the disclosure of the abuse to parents or caregivers while controlling for characteristics of the abuse. Female college students between 17 and 24 years of age (M = 19.44, SD = 1.64) from a southern Spanish University were surveyed. Of 1547 respondents, 153 (9.90%) reported having suffered some form of CSA before the age of 15. Information about the characteristics of abuse (age of onset, type of abuse suffered, continuity of abuse, and relationship with and age of the perpetrator) and the existence of abuse disclosure by the survivor was obtained from a self-reported questionnaire developed for the present study. The Attributions of Responsibility and Blame Scale (McMillen & Zuravin, 1997) was used to assess attributions made about CSA (self-blame, perpetrator blame and family blame). The results of a logistic regression model was statistically significant, χ² (9) = 43.856, p < .001. The model explained 41% (Nagelkerke R²) of the variance of abuse disclosure and correctly classified 85.6% of cases. Survivor disclosure was 5.50 times more likely to occur when the perpetrator was not a family member (Wald = 8.14, p < .01) and 3.95 times more likely to occur when there was not physical contact with the perpetrator (Wald = 4.30, p < .05). The occurrence of disclosure was also related to increased perpetrator age (Wald = 4.83, p < .05). With regard to the attributions of blame, the occurrence of disclosure was related to lower scores on self-blame (Wald = 6.78, p < .01) and higher scores on family blame (Wald = 9.67, p < .001). However, no relationship was found between perpetrator blame and disclosure of abuse. The results confirm the idea that not only self-blame attributions, but also family blame attributions are critical to the decision of a CSA victim to disclose abuse. The possibility that children who do not disclose abuse have a greater need to deny the occurrence of abuse, or have more confusion about being abused is discussed. Attributions of blame should be taken into serious consideration when evaluating children for possible sexual abuse.
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Rare plant conservation efforts must utilize current genetic methods to ensure the evolutionary potential of populations is preserved. One such effort involves the Key Tree Cactus, Pilosocereus robinii, which is an endangered columnar cactus native to the Florida Keys. The populations have precipitously declined over the past decade because of habitat loss and increasing soil salinity from rising sea levels and storm surge. Next-generation DNA sequencing was used to assess the genetic structure of the populations. Twenty individuals representative of both wild and extirpated cacti were chosen for Restriction Site Associated DNA (RAD) analysis. Samples processed using the HindIII and NotIII restriction enzymes produced 82,382,440 high quality reads used for genetic mapping, from which 5,265 Single Nucleotide Polymorphisms (SNPs) were discovered. The analysis revealed that the Keys’ populations are closely related with little population differentiation. In addition, the populations display evidence of inbreeding and low genetic diversity.
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Acute respiratory distress syndrome (ARDS) is a complex disease associated with high morbidity and mortality. Biomarkers and specific pharmacologic treatment of the syndrome are lacking. MicroRNAs (miRNAs) are small (∼19–22 nucleotides) noncoding RNA molecules whose function is the regulation of gene expression. Their uncommon biochemical characteristics (eg, their resistance to degradation because of extreme temperature and pH fluctuations, freeze-thaw cycles, long storage times in frozen conditions, and RNAse digestion) and their presence in a wide range of different biological fluids and the relatively low number of individual miRNAs make these molecules good biomarkers in different clinical conditions. In addition, miRNAs are suitable therapeutic targets as their expression can be modulated by different available strategies. The aim of the present review is to offer clinicians a global perspective of miRNA, covering their structure and nomenclature, biogenesis, effects on gene expression, regulation of expression, and features as disease biomarkers and therapeutic targets, with special attention to ARDS. Because of the early stage of research on miRNAs applied to ARDS, attention has been focused on how knowledge sourced from basic and translational research could inspire future clinical studies.
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This study is designed to give a brief presentation of the judicial structure of South Carolina without going into the matters of procedure. The text of the study describes the manner of selection of the judges and the jurisdiction of each court. The accompanying chart attempts to show the different types and levels of courts in the state system and the chain of appeals from lower to higher courts.
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The chemistry of black seabream Spondyliosoma cantharus otoliths from three main fishery grounds (Olhao, Sagres and Sesimbra) located along c. 400 km of the Portuguese south and west coasts was examined. Element:Ca ratios were determined in whole otoliths and otolith cores of young adult specimens of 23 years of age. Using the data from whole otoliths, it was possible to discriminate among S. cantharus from the three fishing grounds with an average accuracy of 91%. Differences among fishing grounds were significant for all element:Ca ratios, and otoliths from Sagres had significantly higher levels of all ratios compared to the other fishing grounds. In contrast, the chemical composition of the otolith core, representative of the larval stage, showed limited variation among the fishing grounds, with an average discrimination accuracy of only 44%, although the Mg:Ca ratio of the otolith cores was also significantly higher for the Sagres samples. The data suggest that larval stages experienced a homogenous environment consistent with an offshore oceanic spawning. Juveniles appeared to display local residency on the inshore fishing grounds, areas probably characterized by greater environmental heterogeneity. Spondyliosoma cantharus population structure is consistent with distinct local population units that share a spawning ground providing recruits to different coastal fishery areas.
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Despite the ecological and economic importance of passion fruit (Passiflora spp.), molecular markers have only recently been utilized in genetic studies of this genus. In addition, both basic genetic researches related to population studies and pre-breeding programs of passion fruit remain scarce for most Passiflora species. Considering the number of Passiflora species and the increasing use of these species as a resource for ornamental, medicinal, and food purposes, the aims of this review are the following: (i) to present the current condition of the passion fruit crop; (ii) to quantify the applications and effects of using molecular markers in studies of Passiflora; (iii) to present the contributions of genetic engineering for passion fruit culture; and (iv) to discuss the progress and perspectives of this research. Thus, the present review aims to summarize and discuss the relationship between historical and current progress on the culture, breeding, and molecular genetics of passion fruit.
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It is well known that trichomes protect plant organs, and several studies have investigated their role in the adaptation of plants to harsh environments. Recent studies have shown that the production of hydrophilic substances by glandular trichomes and the deposition of this secretion on young organs may facilitate water retention, thus preventing desiccation and favouring organ growth until the plant develops other protective mechanisms. Lychnophora diamantinana is a species endemic to the Brazilian 'campos rupestres' (rocky fields), a region characterized by intense solar radiation and water deficits. This study sought to investigate trichomes and the origin of the substances observed on the stem apices of L. diamantinana. Samples of stem apices, young and expanded leaves were studied using standard techniques, including light microscopy and scanning and transmission electron microscopy. Histochemical tests were used to identify the major groups of metabolites present in the trichomes and the hyaline material deposited on the apices. Non-glandular trichomes and glandular trichomes were observed. The material deposited on the stem apices was hyaline, highly hydrophilic and viscous. This hyaline material primarily consists of carbohydrates that result from the partial degradation of the cell wall of uniseriate trichomes. This degradation occurs at the same time that glandular trichomes secrete terpenoids, phenolic compounds and proteins. These results suggest that the non-glandular trichomes on the leaves of L. diamantinana help protect the young organ, particularly against desiccation, by deposition of highly hydrated substances on the apices. Furthermore, the secretion of glandular trichomes probably repels herbivore and pathogen attacks.
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Human Neks are a conserved protein kinase family related to cell cycle progression and cell division and are considered potential drug targets for the treatment of cancer and other pathologies. We screened the activation loop mutant kinases hNek1 and hNek2, wild-type hNek7, and five hNek6 variants in different activation/phosphorylation statesand compared them against 85 compounds using thermal shift denaturation. We identified three compounds with significant Tm shifts: JNK Inhibitor II for hNek1(Δ262-1258)-(T162A), Isogranulatimide for hNek6(S206A), andGSK-3 Inhibitor XIII for hNek7wt. Each one of these compounds was also validated by reducing the kinases activity by at least 25%. The binding sites for these compounds were identified by in silico docking at the ATP-binding site of the respective hNeks. Potential inhibitors were first screened by thermal shift assays, had their efficiency tested by a kinase assay, and were finally analyzed by molecular docking. Our findings corroborate the idea of ATP-competitive inhibition for hNek1 and hNek6 and suggest a novel non-competitive inhibition for hNek7 in regard to GSK-3 Inhibitor XIII. Our results demonstrate that our approach is useful for finding promising general and specific hNekscandidate inhibitors, which may also function as scaffolds to design more potent and selective inhibitors.
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Context. The possibility of cephalic venous hypertension with the resultant facial edema and elevated cerebrospinal fluid pressure continues to challenge head and neck surgeons who perform bilateral radical neck dissections during simultaneous or staged procedures. Case Report. The staged procedure in patients who require bilateral neck dissections allows collateral venous drainage to develop, mainly through the internal and external vertebral plexuses, thereby minimizing the risks of deleterious consequences. Nevertheless, this procedure has disadvantages, such as a delay in definitive therapy, the need for a second hospitalization and anesthesia, and the risk of cutting lymphatic vessels and spreading viable cancer cells. In this paper, we discuss the rationale and feasibility of preserving the external jugular vein. Considering the limited number of similar reports in the literature, two cases in which this procedure was accomplished are described. The relevant anatomy and technique are reviewed and the patients' outcomes are discussed. Conclusion. Preservation of the EJV during bilateral neck dissections is technically feasible, fast, and safe, with clinically and radiologically demonstrated patency.
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The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.
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Ofloxacin is an antimicrobial agent frequently found in significant concentrations in wastewater and surface water. Its continuous introduction into the environment is a potential risk to non-target organisms or to human health. In this study, ofloxacin degradation by UV/TiO2 and UV/TiO2/H2O2, antimicrobial activity (E. coli) of samples subjected to these processes, and by-products formed were evaluated. For UV/TiO2, the degradation efficiency was 89.3% in 60 min of reaction when 128 mg L(-1) TiO2 were used. The addition of 1.68 mmol L(-1) hydrogen peroxide increased degradation to 97.8%. For UV/TiO2, increasing the catalyst concentration from 4 to 128 mg L(-1) led to an increase in degradation efficiency. For both processes, the antimicrobial activity was considerably reduced throughout the reaction time. The structures of two by-products are presented: m/z 291 (9-fluoro-3-methyl-10-(methyleneamino)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid) and m/z 157 ((Z)-2-formyl-3-((2-oxoethyl)imino)propanoic acid).