884 resultados para 3 BODY PROBLEM
Resumo:
The (2)H(d,p)(3)H and (2)H(d,n)(3)He reactions have been indirectly studied by means of the Trojan Horse Method applied to the quasi-free (2)H((3)He, p(3)H)(1)H (2)H((3)He, n(3)He)(1)H reaction at 18 MeV of beam energy. This is the first experiment where the spectator (here (1)H) has been detected in coincidence with the charged participant, avoiding the limitations of standard neutron detectors. The d - d relative energy has been measured from 1.5 MeV down to 2 keV, at center of mass angles from 40A degrees to 170A degrees. Indirect angular distributions are compared with the direct behaviour in the overlapping regions.
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Chagas` disease, a parasitic infection caused by the flagellate protozoan Trypanosoma cruzi, is a major public health problem affecting millions of individuals in Latin America. On the basis of the essential role in the life cycle of T. cruzi, the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has been considered an attractive target for the development of novel antitrypanosomatid agents. In the present work, we describe the inhibitory effects of a small library of natural and synthetic anacardic acid derivatives against the target enzyme. The most potent inhibitors, 6-n-pentadecyl-(1) and 6-n-dodecylsalicilic acids (10e), have IC(50) values of 28 and 55 mu M, respectively. The inhibition was not reversed or prevented by the addition of Triton X-100, indicating that aggregate-based inhibition did not occur. In addition, detailed mechanistic characterization of the effects of these compounds on the T. cruzi GAPDH-catalyzed reaction showed clear noncompetitive inhibition with respect to both substrate and cofactor. (C) 2008 Elsevier Ltd. All rights reserved.
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Trace element and isotopic data obtained for mantle spinel Iherzolites and diorite dykes from the Baldissero massif (Ivrea-Verbano Zone, Western Italy) provide new, valuable constraints on the petrologic and geodynamic evolution of the Southern Alps in Paleozoic to Mesozoic times. Whole rock and mineral chemistry indicates that Baldissero Iherzolites can be regarded as refractory mantle residues following limited melt extraction. In particular, the Light Rare Earth Elements (LREE)-depleted and fractionated compositions of whole rock and clinopyroxene closely match modelling results for refractory residues after low degrees (similar to 4-5%) of near-fractional melting of depleted mantle, possibly under garnet-facies conditions. Following this, the peridotite sequence experienced subsolidus re-equilibration at lithospheric spinel-facies conditions and intrusion of several generations of dykes. However, Iherzolites far from dykes show very modest metasomatic changes, as evidenced by the crystallisation of accessory titanian pargasite and the occurrence of very slight enrichments in highly incompatible trace elements (e.g. Nb). The Re-Os data for Iherzolites far from the dykes yield a 376 Ma (Upper Devonian) model age that is considered to record a partial melting event related to the Variscan orogenic cycle s.l. Dioritic dykes cutting the mantle sequence have whole rock, clinopyroxene and plagioclase characterised by high radiogenic Nd and low radiogenic Sr, which point to a depleted to slightly enriched mantle source. Whole rock and mafic phases of diorites have high Mg# values that positively correlate with the incompatible trace element concentrations. The peridotite at the dyke contact is enriched in orthopyroxene, iron and incompatible trace elements with respect to the Iherzolites far from dykes. Numerical simulations indicate that the geochemical characteristics of the diorites can be explained by flow of a hydrous, silica-saturated melt accompanied by reaction with the ambient peridotite and fractional crystallisation. The composition of the more primitive melts calculated in equilibrium with the diorite minerals show tholeiitic to transitional affinity. Internal Sm-Nd, three-point isochrons obtained for two dykes suggest an Upper Triassic-Lower Jurassic emplacement age (from 204 31 to 198 29 Ma). Mesozoic igneous events are unknown in the southern Ivrea-Verbano Zone (IVZ), but the intrusion of hydrous melts, mostly silica-saturated, have been well documented in the Finero region, i.e. the northernmost part of IVZ and Triassic magmatism with calc-alkaline to shoshonitic affinity is abundant throughout the Central-Eastern Alps. The geochemical and chronological features of the Baldissero diorites shed new light on the geodynamic evolution of the Southern Alps before the opening of the Jurassic Tethys. (C) 2010 Elsevier B.V. All rights reserved.
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This paper presents the formulation of a combinatorial optimization problem with the following characteristics: (i) the search space is the power set of a finite set structured as a Boolean lattice; (ii) the cost function forms a U-shaped curve when applied to any lattice chain. This formulation applies for feature selection in the context of pattern recognition. The known approaches for this problem are branch-and-bound algorithms and heuristics that explore partially the search space. Branch-and-bound algorithms are equivalent to the full search, while heuristics are not. This paper presents a branch-and-bound algorithm that differs from the others known by exploring the lattice structure and the U-shaped chain curves of the search space. The main contribution of this paper is the architecture of this algorithm that is based on the representation and exploration of the search space by new lattice properties proven here. Several experiments, with well known public data, indicate the superiority of the proposed method to the sequential floating forward selection (SFFS), which is a popular heuristic that gives good results in very short computational time. In all experiments, the proposed method got better or equal results in similar or even smaller computational time. (C) 2009 Elsevier Ltd. All rights reserved.
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For a fixed family F of graphs, an F-packing in a graph G is a set of pairwise vertex-disjoint subgraphs of G, each isomorphic to an element of F. Finding an F-packing that maximizes the number of covered edges is a natural generalization of the maximum matching problem, which is just F = {K(2)}. In this paper we provide new approximation algorithms and hardness results for the K(r)-packing problem where K(r) = {K(2), K(3,) . . . , K(r)}. We show that already for r = 3 the K(r)-packing problem is APX-complete, and, in fact, we show that it remains so even for graphs with maximum degree 4. On the positive side, we give an approximation algorithm with approximation ratio at most 2 for every fixed r. For r = 3, 4, 5 we obtain better approximations. For r = 3 we obtain a simple 3/2-approximation, achieving a known ratio that follows from a more involved algorithm of Halldorsson. For r = 4, we obtain a (3/2 + epsilon)-approximation, and for r = 5 we obtain a (25/14 + epsilon)-approximation. (C) 2008 Elsevier B.V. All rights reserved.
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Lead (Pb) poisoning is preventable but continues to be a public health problem in several countries. Measuring Pb in the surface dental enamel (SDE) using microbiopsies is a rapid, safe, and painless procedure. There are different protocols to perform these microbiopsies, but the reliability of dental enamel lead levels (DELL) determination is dependent upon biopsy depth (BD). It is established that DELL decrease from the outermost superficial layer to the inner layer of dental enamel. The aim of this study was to determine DELL obtained by two different microbiopsy techniques on SDE termed protocol I and protocol II. Two consecutive enamel layers were removed from the same subject group (n = 138) for both protocols. Protocol I consisted of a biopsied site with a diameter of 4 mm after the application of 10 l HCl for 35 s. Protocol II involved a biopsied site of 1.6 mm diameter after application of 5 l HCl for 20 s. The results demonstrated that there were no significant differences for BD and DELL between homologous teeth using protocol I. However, there was a significant difference between DELL in the first and second layers using both protocols. Further, the BD in protocol II overestimated DELL values. In conclusion, SDE analyzed by microbiopsy is a reliable biomarker in protocol I, but the chemical method to calculate BD in protocol II appeared to be inadequate for measurement of DELL. Thus, DELL could not be compared among studies that used different methodologies for SDE microbiopsies.
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In general, patient participation is regarded as being informed and partaking in decision making regarding one’s care and treatment. This interpretation is common in legislation throughout the Western world and corresponding documents guiding health care professionals, as well as in scientific studies. Even though this understanding of the word participation can be traced to a growing emphasis on individuals’ autonomy in society and to certain dictionary defi nitions, there are other ways of understanding participation from a semantic point of view, and no trace of patients’ descriptions of what it is to participate can be found in these definitions. Hence, the aim of this dissertation was to understand patients’ experience of the phenomenon of patient participation. An additional aim was to understand patients’ experience of non-participation and to describe the conditions for patient participation and non-participation, in order to understand the prerequisites for patient participation. The dissertation comprises four papers. The philosophical ideas of Ricoeur provided a basis for the studies: how communication can present ways to understand and explain experiences of phenomena through phenomenological hermeneutics. The first and second studies involved a group of patients living with chronic heart failure. For the fi rst study, 10 patients were interviewed, with a narrative approach, about their experience of participation and non-participation, as defi ned by the participants. For the second study, 11 visits by three patients at a nurse-led outpatient clinic were observed, and consecutive interviews were performed with the patients and the nurses, investigating what they experience as patient participation and non-participation. A triangulation of data was performed to analyse the occurrence of the phenomena in the observed visits. For paper 3 and 4, a questionnaire was developed and distributed among a diverse group of people who had recent experience of being patients. The questionnaire comprised respondent’s description of what patient participation is, using items based on findings in Study 1, along with open-ended questions for additional aspects and general issues regarding situations in which the respondent had experienced patient participation and/or non-participation. The findings show additional aspects to patient participation: patient participation is being provided with information and knowledge in order for one to comprehend one’s body, disease, and treatment and to be able to take self-care actions based on the context and one’s values. Participation was also found to include providing the information and knowledge one has about the experience of illness and symptoms and of one’s situation. Participation occurs when being listened to and being recognised as an individual and a partner in the health care team. Non-participation, on the other hand, occurs when one is regarded as a symptom, a problem to be solved. To avoid non-participation, the information provided needs to be based on the individual’s need and with recognition of the patient’s knowledge and context. In conclusion, patient participation needs to be reconsidered in health care regulations and in clinical settings: patients’ defi nitions of participation, found to be close to the dictionaries’ description of sharing, should be recognised and opportunities provided for sharing knowledge and experience in two-way-communication.
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Elever arbetar ofta med textuppgifter när de arbetar med matematisk problemlösning och förståelsen av textuppgifter kan vara problematisk för många elever. Som lärare är det viktigt att veta vad som är svårt och vad som kan underlätta förståelsen för elever. I denna litteraturstudie undersöks vilka språkliga aspekter som kan försvåra för elever i årskurs 1-3 när de läser matematiska textuppgifter samt vilka undervisningsstrategier som kan underlätta förståelsen. Studier på svenska och engelska från år 2000-2014 togs fram genom en systematisk sökning i databaserna LIBRIS och ERIC. Resultatet visar att begrepp, symboler och siffersymboler kan försvåra förståelsen. En studie visar att textförståelse är den största bristen medan en annan studie visar att det är i valet av räknesätt det brister. I resultatet tas strategin mental modeling upp som handlar om att skapa mentala bilder och åtta andra förslag som kan underlätta förståelsen, till exempel att elever kan skriva egna matematiska problem och att de behöver god tid på sig att förstå texter. I diskussionen tas upp hur dessa undervisningsstrategier kan minska de språkliga aspekter som försvårar. Elever kan få bättre förståelse för språket om de skriver egna textuppgifter eller om lärare vidgar elevers matematiska ordförråd genom att vara ”tvåspråkiga”. Det råder delade meningar om elever verkligen behöver lära sig speciella strategier för att förstå matematiska texter.
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The weight order – an analytical perspective This article is an outline of a critically oriented and empirically grounded theory of the weight order, as a complement to theories of more widely recognized and studied ordering systems. We 1) expose the weight orders “absent presence” in humanistic and social science-oriented research treating overweight and fatness as a personal or social problem, 2) outline the contours and characteristics of this specific ordering system, and 3) suggest a set of sensitizing concepts for analysis of this ordering system. Two primary forms of activity, maintaining order and putting in order, are analysed. The first is making thin people into order and overweight people into disorder, and thus maintains order in the weight order. The other, putting in order, covers different activities supposed to make sure that people keep their bodies thin or try to become thin. These ordering activities meet resistance when overweight people stop dieting and/or define overweight as a personal choice and themselves as good enough, or even healthy and beautiful. We call these forms of resistance alternative weight-doings.
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Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. To adequately evaluate an elite skier’s performance capability, it is essential to establish the optimal ratio between the physiological variable and body mass. The overall aim of this doctoral thesis was to investigate the importance of body-mass exponent optimization for the evaluation of performance capability in cross-country skiing. Methods In total, 83 elite cross-country skiers (56 men and 27 women) volunteered to participate in the four studies. The physiological variables of maximal oxygen uptake (V̇O2max) and oxygen uptake corresponding to a blood-lactate concentration of 4 mmol∙l-1 (V̇O2obla) were determined while treadmill roller skiing using the diagonal-stride technique; mean oxygen uptake (V̇O2dp) and upper-body power output (Ẇ) were determined during double-poling tests using a ski-ergometer. Competitive performance data for elite male skiers were collected from two 15-km classical-technique skiing competitions and a 1.25-km sprint prologue; additionally, a 2-km double-poling roller-skiing time trial using the double-poling technique was used as an indicator of upper-body performance capability among elite male and female junior skiers. Power-function modelling was used to explain the race and time-trial speeds based on the physiological variables and body mass. Results The optimal V̇O2max-to-mass ratios to explain 15-km race speed were V̇O2max divided by body mass raised to the 0.48 and 0.53 power, and these models explained 68% and 69% of the variance in mean skiing speed, respectively; moreover, the 95% confidence intervals (CI) for the body-mass exponents did not include either 0 or 1. For the modelling of race speed in the sprint prologue, body mass failed to contribute to the models based on V̇O2max, V̇O2obla, and V̇O2dp. The upper-body power output-to-body mass ratio that optimally explained time-trial speed was Ẇ ∙ m-0.57 and the model explained 63% of the variance in speed. Conclusions The results in this thesis suggest that V̇O2max divided by the square root of body mass should be used as an indicator of performance in 15-km classical-technique races among elite male skiers rather than the absolute or simple ratio-standard scaled expression. To optimally explain an elite male skier’s performance capability in sprint prologues, power-function models based on oxygen-uptake variables expressed absolutely are recommended. Moreover, to evaluate elite junior skiers’ performance capabilities in 2-km double-poling roller-skiing time trials, it is recommended that Ẇ divided by the square root of body mass should be used rather than absolute or simple ratio-standard scaled expression of power output.
Resumo:
Syftet med studien var att ta reda på hur lärare ser på närområdet och hur de bedriver undervisning i närområdet utanför klassrummet inom de samhällsorienterande ämnena i årskurs 1-3. Vidare var syftet att undersöka vad lärare hade för åsikter om undervisningens inverkan på elevers lärande i årskurs 1-3 samt vad de såg för möjligheter och problem med undervisningsformen. För att besvara studiens syfte intervjuades sex lärare genom semistrukturerade intervjuer. Intervjuerna analyserades med en innehållsanalys där mönster söktes i informanternas svar. Resultatet visade att samtliga lärare anser att undervisning i närområdet utanför klassrummet har en positiv inverkan på elevers lärande men att alla lärare inte bedriver undervisning i denna form. Problem som hindrar lärare från att bedriva undervisning i närområdet är tids- och ekonomibrist samt bristen på forskning inom ämnet och vissa lärare saknar även viljan till att bedriva undervisning på detta sätt. I resultatet presenteras även några olika exempel på hur lärare undervisar i närområdet utanför klassrummet och vad de ser för möjligheter med denna undervisningsform.