57 resultados para reappearance
Resumo:
A high-resolution, accelerator mass spectroscopy 14C dated sediment record from the Sulu Sea clearly indicates that the Younger Dryas event affected the western equatorial Pacific. Planktonic foraminiferal delta18O and abundance data both record significant changes during Younger Dryas time. In particular, a 0.4 per mil increase in the delta18O value of Globigerinoides ruber and the reappearance of the cool water planktonic foraminifera, Neogloboquadrina pachyderma, occur during the Younger Dryas at this location. These isotopic and faunal changes are a response to either surface water temperature or salinity changes, or some combination of the two. Changes in surface salinities could have been accomplished through either local or global processes. Intensification of the monsoon climate system and increased precipitation at approximately 11 ka is one mechanism that may have resulted in local changes in salinity. A meltwater pulse derived from the Tibetan Plateau is another mechanism which may have caused local changes in salinity. The presence of the Younger Dryas in the tropical western Pacific clearly indicates that this climatic event is not restricted to the North Atlantic or high latitudes, but rather is global in extent.
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We previously have demonstrated that insulin and insulin-like growth factor-I (IGF-I) down-regulate growth hormone (GH) binding in osteoblasts by reducing the number of surface GH receptors (GHRs). The present study was undertaken to investigate the mechanism of GHR down-regulation. Treatment with 5 nM insulin or IGF-I for 18 hr significantly decreased surface GH binding to 26.4 ± 2.9% and 23.0 ± 2.7% of control (mean ± SE; P < 0.05), respectively. No corresponding reductions in the mRNA level and total cellular content of GHR were found, nor was the rate of receptor internalization affected. The effects on GHR translocation were assessed by measuring the reappearance of GH binding of whole cells after trypsinization to remove the surface receptors. GH binding of control cultures significantly increased (P < 0.05) over 2 hr after trypsinization, whereas no recovery of binding activity was detected in insulin and IGF-I-treated cultures, indicating that GHR translocation was impaired. Studies on the time course of GHR down-regulation revealed that surface GH binding was reduced significantly by 3-hr treatment (P ≤ 0.0005), whereas GHR translocation was completely abolished by 75–90 min with insulin and IGF-I. The inhibition of receptor translocation by insulin, but not IGF-I, was attenuated by wortmannin. In conclusion, insulin and IGF-I down-regulated GH binding in osteoblasts by acutely impairing GHR translocation, with their effects exerted through distinct postreceptor signaling pathways.
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When performed at increased external [Ca2+]/[Mg2+] ratio (2.5 mM/0.5 mM), temporary block of A1 adenosine receptors in hippocampus [by 8-cyclopentyltheophylline (CPT)] leads to a dramatic and irreversible change in the excitatory postsynaptic current (EPSC) evoked by Schaffer collateral/commissural (SCC) stimulation and recorded by in situ patch clamp in CA1 pyramidal neurons. The duration of the EPSC becomes stimulus dependent, increasing with increase in stimulus strength. The later occurring component of the EPSC is carried through N-methyl-D-aspartate (NMDA) receptor-operated channels but disappears under either the NMDA antagonist 2-amino-5-phosphonovaleric acid (APV) or the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). These findings indicate that the late component of the SCC-evoked EPSC is polysynaptic: predominantly non-NMDA receptor-mediated SCC inputs excite CA1 neurons that recurrently excite each other by predominantly NDMA receptor-mediated synapses. These recurrent connections are normally silent but become active after CPT treatment, leading to enhancement of the late component of the EPSC. The activity of these connections is maintained for at least 2 hr after CPT removal. When all functional NMDA receptors are blocked by dizocilpine maleate (MK-801), subsequent application of CPT leads to a partial reappearance of NMDA receptor-mediated EPSCs evoked by SCC stimulation, indicating that latent NMDA receptors are recruited. Altogether, these findings indicate the existence of a powerful system of NMDA receptor-mediated synaptic contacts in SCC input to hippocampal CA1 pyramidal neurons and probably also in reciprocal connections between these neurons, which in the usual preparation are kept latent by activity of A1 receptors.
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Background: Adolescent depression prevention research has focused on mean intervention outcomes, but has not considered heterogeneity in symptom course. Here, we empirically identify subgroups with distinct trajectories of depressive symptom change among adolescents enrolled in two indicated depression preven- tion trials and examine how cognitive-behavioral (CB) interventions and baseline predictors relate to trajectory membership. Methods: Six hundred thirty-one participants were assigned to one of three conditions: CB group intervention, CB bibliotherapy, and brochure control. We used group-based trajectory modeling to identify trajectories of depressive symptoms from pretest to 2-year follow-up. We examined associations between class membership and conditions using chi- square tests and baseline predictors using multinomial regressions. Results: We identified four trajectories in the full sample. Qualitatively similar trajectories were found in each condition separately. Two trajectories of positive symptom course (low-declining, high-declining) had declining symptoms and were dis- tinguished by baseline symptom severity. Two trajectories of negative course (high-persistent, resurging), respectively, showed no decline in symptoms or de- cline followed by symptom reappearance. Participants in the brochure control condition were significantly more likely to populate the high-persistent trajectory relative to either CB condition and were significantly less likely to populate the low-declining trajectory relative to CB group. Several baseline factors predicted trajectory classes, but gender was the most informative prognostic factor, with males having increased odds of membership in a high-persistent trajectory rel- ative to other trajectories. Conclusions: Findings suggest that CB preventive interventions do not alter the nature of trajectories, but reduce the risk that adolescents follow a trajectory of chronically elevated symptoms.
Resumo:
Background: Adolescent depression prevention research has focused on mean intervention outcomes, but has not considered heterogeneity in symptom course. Here, we empirically identify subgroups with distinct trajectories of depressive symptom change among adolescents enrolled in two indicated depression preven- tion trials and examine how cognitive-behavioral (CB) interventions and baseline predictors relate to trajectory membership. Methods: Six hundred thirty-one participants were assigned to one of three conditions: CB group intervention, CB bibliotherapy, and brochure control. We used group-based trajectory modeling to identify trajectories of depressive symptoms from pretest to 2-year follow-up. We examined associations between class membership and conditions using chi- square tests and baseline predictors using multinomial regressions. Results: We identified four trajectories in the full sample. Qualitatively similar trajectories were found in each condition separately. Two trajectories of positive symptom course (low-declining, high-declining) had declining symptoms and were dis- tinguished by baseline symptom severity. Two trajectories of negative course (high-persistent, resurging), respectively, showed no decline in symptoms or de- cline followed by symptom reappearance. Participants in the brochure control condition were significantly more likely to populate the high-persistent trajectory relative to either CB condition and were significantly less likely to populate the low-declining trajectory relative to CB group. Several baseline factors predicted trajectory classes, but gender was the most informative prognostic factor, with males having increased odds of membership in a high-persistent trajectory rel- ative to other trajectories. Conclusions: Findings suggest that CB preventive interventions do not alter the nature of trajectories, but reduce the risk that adolescents follow a trajectory of chronically elevated symptoms.
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The first and last appearances of Quaternary planktonic foraminifers in the Great Australian Bight were evaluated using datum levels from magnetostatigraphy, oxygen isotope stratigraphy, and calcareous nannofossil biostratigraphy to determine whether they were synchronous or diachronous with open-ocean biostratigraphic events. The first appearance of Globorotalia truncatulinoides is diachronous at 1.6-1.7 Ma at Site 1127 and 1.1-1.2 at Sites 1129 and 1132, similar to other local appearances in high latitudes. All other datum levels, however, are synchronous with open-ocean events, including the first appearance of Globorotalia hirsuta and the last appearances of Globorotalia tosaensis and pink Globigerinoides ruber in the Indo-Pacific region. A local reappearance of Gt. hirsuta at ~0.12 Ma and the disappearance of Globorotalia crassaformis at ~0.10 Ma were found to be useful for local biostratigraphy. Age control at the bottom of all of the sections is poor at this time, but results suggest that sedimentation recommenced starting at ~1.9 Ma above the regional unconformity that marks the base of seismostratigraphic Sequence 2. Sediment accumulation is distinctly reduced in the lower Pleistocene compared to the upper Pleistocene, perhaps in part because of processes associated with several omission surfaces.
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Perceptual rivalry is an oscillation of conscious experience that takes place despite univarying, if ambiguous, sensory input. Much current interest is focused on the controversy over the neural site of binocular rivalry, a variety of perceptual rivalry for which a number of different cortical regions have been implicated. Debate continues over the relative role of higher levels of processing compared with primary visual cortex and the suggestion that different forms of rivalry involve different cortical areas. Here we show that the temporal pattern of disappearance and reappearance in motion-induced blindness (MIB) (Bonneh et al, 2001 Nature 411 798-801) is highly correlated with the pattern of oscillation reported during binocular rivalry in the same individual. This correlation holds over a wide range of inter-individual variation. Temporal similarity in the two phenomena was strikingly confirmed by the effects of the hallucinogen LSD, which produced the same, extraordinary, pattern of increased rhythmicity in both kinds of perceptual oscillation. Furthermore, MIB demonstrates the two properties previously considered characteristic of binocular rivalry. Namely the distribution of dominance periods can be approximated by a gamma distribution and, in line with Levelt's second proposition of binocular rivalry, predominance of one perceptual phase can be increased through a reduction in the predominance time of the opposing phase. We conclude that (i) MIB is a form of perceptual rivalry, and (ii) there may be a common oscillator responsible for timing aspects of all forms of perceptual rivalry.
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Postantibiotic effect (PAE) describes the suppression of microbial growth occurring after a short exposure to an antimicrobial agent. PAE appears to be a property of the majority of antimicrobial agents and is demonstrated by a wide variety of microorganisms. At present, carbapenems and penems are the only members of the -lactam group of antimicrobial agents that exhibit a significant PAE on Gram-negative bacilli. A standardised method was developed to evaluate the in vitro PAE of three carbapenems; imipenem, meropenem and biapenem on Gram-negative bacteria under reproducible laboratory conditions that partially mimicked those occurring in vivo. The effects on carbapenem PAE of the method of antimicrobial removal, concentration, exposure duration, inoculum size, inoculum growth phase, multiple exposures and pooled human serum were determined. Additionally, the reproducibility, susceptibility prior to and after PAE determination and inter-strain variation of carbapenem PAE were evaluated. The method developed determined PAE by utilising viable counts and demonstrated carbapenem PAE to be reproducible, constant over successive exposures, dependent on genera, concentration, duration of exposure, inoculum size and growth phase. In addition, carbapenem PAE was not significantly effected either by agitation, the antimicrobial removal method or the viable count diluent. At present, the mechanism underlying PAE is undetermined. It is thought to be due to either the prolonged persistence of the antimicrobial at the cellular site of action or the true recovery period from non-lethal damage. Increasing the L-lysine concentration and salinity at recovery decreased and increased the carbapenem and imipenem PAE of Pseudomonas aeruginosa, respectively. In addition, no apparent change was observed in the production of virulence factors by P.aeruginosa in PAE phase. However, alterations in cell morphology were observed throughout PAE phase, and the reappearance of normal cell morphology corresponded to the duration of PAE determined by viable count. Thus, the recovery of the penicillin binding protein target enzymes appears to be the mechanism behind carbapenem PAE in P. aeruginosa.
Resumo:
Radiocarbon-age measurements on single species of foraminifera from a core on the Ceara Rise demonstrate the importance of the joint effect of bioturbation and variable rain abundance of foraminifera. The relatively high mixed layer ages for Pulleniatina obliquiloculata reflect, at least in part, an early Holocene peak in its abundance while the relatively young ages for Globorotalia menardii reflect the delay until mid Holocene of its reappearance in the Atlantic Ocean. These results clearly demonstrate that core-top sediment samples need not be representative foraminifera falling from today's surface ocean. Rather, at least on the Ceara Rise, such samples consist of a composite of changing species groupings. These results also reconfirm the pitfalls associated with attempts to reconstruct the radiocarbon age of deep ocean water on the basis of benthic-planktonic foraminiferal age differences.
Resumo:
Este estudo exploratório, de caráter descritivo, tem como objetivos compreender a relação do Estado com a organização profissional dos assistentes sociais nas diferentes conjunturas sócio-históricas da trajetória da profissão; conhecer o contributo do associativismo sindical e profissional para a organização dos assistentes sociais em Portugal; caraterizar as diversas formas de associativismo profissional e sindical dos profissionais de Serviço Social e compreender a importância da regulação profissional para a categoria. Na trajetória do Serviço Social no nosso país, identificámos várias estruturas associativas desde os anos 50 do século XX. Apesar dessa diversidade ao nível da organização profissional, nos últimos anos tem sido o projeto de constituição da ordem o que tem congregado os profissionais de Serviço Social, embora de forma fragmentada. Em Portugal não existe um estatuto jurídico de regulação da profissão de assistente social, sendo do interesse dos profissionais, utentes e sociedade que o mesmo seja efetivado. A criação de uma ordem profissional poderá vir a fortalecer o trabalho dos profissionais de Serviço Social, bem como proteger e regulamentar o exercício profissional e a formação académica. Com a erosão do Estado Social, as relações de trabalho tendem a ser desregulamentadas e flexibilizadas, subsistindo a precariedade e o desemprego. O enfrentamento a estas questões por parte do movimento associativo é ténue e a sua não articulação fragiliza a proteção dos profissionais, como indiciam a subsistente ausência da constituição da ordem profissional e a extinção do Sindicato Nacional de Profissionais de Serviço Social, apesar do ressurgimento do associativismo sindical durante o presente ano (2013). As condições atuais diferem das existentes aquando do processo de obtenção da licenciatura e estruturação e implementação das carreiras profissionais de Serviço Social que potenciaram e galvanizaram os assistentes sociais. A categoria profissional apresenta-se desmobilizada e com pouco poder reivindicativo, e as associações profissionais e sindicais vivem com constrangimentos financeiros, funcionando em regime de voluntariado, o que denota a insipiência da sua estrutura organizativa. A atual conjuntura justificaria uma maior convergência, debate e processos de resistência por parte das estruturas associativas face ao agravamento de políticas baseadas na austeridade, que têm reflexos no mercado de trabalho, formação e organização profissional. Parece justificar-se a existência de estratégias articuladas com maior clareza sobre o projeto para a categoria, apostando num debate que se faça com os seus diversos intervenientes. Desta forma, o associativismo poderá constituir uma alavanca que confira maior dinamismo às suas estruturas organizacionais, maior visibilidade e presença pública da categoria, mas também uma maior solidez das suas organizações, que não sendo corporativas ou elitistas, salientem o primado da ética do serviço sobre a ética do ganho. / This descriptive exploratory study aims to understand the relationship between the State and the professional organisation of the social workers in the different social-historical situations of the profession course; to know the contribute of the unions and professional membership drive to the organisation of the social workers in Portugal; to characterise the several ways of the social workers’ professional and union membership drive and to understand the importance of the professional regulation for the area. In the Social Service trajectory in our country, we have identified several associative structures since the 1950s. Despite this diversity concerning the professional organisation, the project of constituting the professional order has been responsible for the social workers’ congregation in the past years, although in a fragmented way. In Portugal, there is not a legal status of regulation of the social workers’ profession, and it is of the interest of the professionals, users and society that this may be brought about. The creation of a professional order may strengthen the activity of the social workers, as well as it may protect and regulate the profession exercise and the university education. With the Social State’s erosion, the work relationships tend to be deregulated and softened, persisting the job insecurity and the unemployment. The associative movement does not strongly face these issues, and its non-articulation weakens the professionals’ protection, as the permanent absence of the professional order creation and the extinction of the National Social Workers Union show, despite the reappearance of the union membership drive during the present year (2013). The current conditions are not equal to the ones existent in the process of obtaining the university degree and the structuring and implementing of professional careers in the Social Service area, which have strengthened and galvanised the social workers. The professional category is not mobilised and it has few claimable power; the professional and unions’ associations live with financial problems, functioning in a volunteering regime, which shows the insipience of its organisation structure. The current situation would justify a bigger convergence, debate and resistance processes on behalf of the associative structures regarding the worsening of policies based on austerity – this has consequences in the work market, training and professional organisation. It seems to be pertinent the existence of strategies articulated in a clearer way about the project for this professional area, investing in a debate among its several participants. Therefore, the professional membership drive may constitute a lever that can give more dynamism to its organisational structures, a bigger visibility and public presence of the area, but also a stronger solidity in its organisations which, being not corporative or elitist, may highlight the service’s ethics over the profit’s ethics.
Resumo:
The prevalence of diabetic polyneuropathy in Spain is 22% increasing with age, standing at less than 5% in patients between 15 and 19 years and reaching 29.8% in those aged 70 to 74 years age. Infection is an important complication in Diabetic Foot, frequently associated with minor amputation and even lower extremity amputation. The study presents a clinical case of a 68-year-old man who consulted for a diabetic foot ulcer in the metatarseal area of the right foot, diagnosed two years ago and without healing success. An exploration protocol of the diabetic food was made. Afterwards, a surgical debridement was done and a cure procedure with pure hyaluronic acid, a bandage and foot unloading was followed. After 69 days of treatment, a complete ulcer healing was achieved. After the injure healing, a biomechanical exploration was made and a plantar support was produced to avoid the reappearance of the injury because of local hyperpressure.
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Both ludic and macabre, the theatrical works of Samuel Beckett and Jean Genet are a paradox to behold. Indeed, as this thesis seeks to illustrate, despite their vastly differing aesthetics, at the core of each playwright’s stage productions is a tension between the characters’ yearning for silence and invisibility, and the continual creation of an often humorous, chaotic, exaggerated or theatrical image that depicts this very longing. Seeking an impossible intersection between their image and their death, they are trapped in a double bind that guarantees aesthetic failure. In order to grasp the close, yet delicate, relationship between the image of death and the death of the image, as presented in the plays of Beckett and Genet, we will explore how the characters’ creative processes deflate the very images — both visual and auditory — that they create. More specifically, we will examine how mimesis both liberates and confines the characters; while the symbolic realm provides the only means of self-representation, it is also a source of profound alienation and powerlessness, for it never adequately conveys meaning. Thus, body, gesture, language and voice are each the site of simultaneous and ceaseless reappearance and disappearance, for which death remains the only (aporetic) cure. Struggling against theatrical form, which demands the actors’ and the audience’s physical presence, both playwrights make shrewd use of metatheatre to slowly empty the stage and thereby suggest the impending, yet impossible, erasure of their characters.