907 resultados para Multi-level analyses
Resumo:
High-resolution lithostratigraphic data from rock sequences known as the Indidura Formation near Parras de La Fuente, Coahuila, NE Mexico, led to achieve a significant improvement of our knowledge of that Formation. The results of this study indicate for the first time that the sequence at Parras de La Fuente developed from the deposition of calcareous cyanobacterial microspheroids that accumulated under perennial blooms during the Late Cenomanian through the Middle Turonian. Multi-proxy analyses included sedimentological, petrographical, scanning electron microscopy, stable isotope, trace element geochemistry, and paleontological data. The combined results allowed the correlation of δ13C and anomalies in Mo, V, and Cr with the abundance and predominance of calcareous cyanobacterial microspheroids, which were the main suppliers of the carbonate components and the organic matter throughout deposition of the Indidura Formation in the Parras de la Fuente area, under dysoxic/anoxic conditions. Conspicuous interbeds of dark and light-gray laminated marly calcilutites, and dark-gray marlstones that characterize the stratigraphic sequence formed in response to external forcing climatic factors of millennial-scale Milankovitch cycles (ca. 20 ka precession). At the microscopic level, the prominent dark and light-gray laminae were formed during cycles similar to the 10 to 15 years solar irradiance maximum, and represent alternating periods of high and low calcareous cyanobacterial microspheroids productivity.
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This study examined a Pseudoword Phonics Curriculum to determine if this form of instruction would increase students’ decoding skills compared to typical real-word phonics instruction. In typical phonics instruction, children learn to decode familiar words which allow them to draw on their prior knowledge of how to pronounce the word and may detract from learning decoding skills. By using pseudowords during phonics instruction, students may learn more decoding skills because they are unfamiliar with the “words” and therefore cannot draw on memory for how to pronounce the word. It was hypothesized that students who learn phonics with pseudowords will learn more decoding skills and perform higher on a real-word assessment compared to students who learn phonics with real words. Students from two kindergarten classes participated in this study. An author-created word decoding assessment was used to determine the students’ ability to decode words. The study was broken into three phases, each lasting one month. During Phase 1, both groups received phonics instruction using real words, which allowed for the exploration of baseline student growth trajectories and potential teacher effects. During Phase 2, the experimental group received pseudoword phonics instruction while the control group continued real-word phonics instruction. During Phase 3, both groups were taught with real-word phonics instruction. Students were assessed on their decoding skills before and after each phase. Results from multiple regression and multi-level model analyses revealed a greater increase in decoding skills during the second and third phases of the study for students who received the pseudoword phonics instruction compared to students who received the real-word phonics instruction. This suggests that pseudoword phonics instruction improves decoding skills quicker than real-word phonics instruction. This also suggests that teaching decoding with pseudowords for one month can continue to improve decoding skills when children return to real-word phonics instruction. Teacher feedback suggests that confidence with reading increased for students who learned with pseudowords because they were less intimidated by the approach and viewed pseudoword phonics as a game that involved reading “silly” words. Implications of these results, limitations of this study, and areas for future research are discussed.
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Research has identified a number of putative risk factors that places adolescents at incrementally higher risk for involvement in alcohol and other drug (AOD) use and sexual risk behaviors (SRBs). Such factors include personality characteristics such as sensation-seeking, cognitive factors such as positive expectancies and inhibition conflict as well as peer norm processes. The current study was guided by a conceptual perspective that support the notion that an integrative framework that includes multi-level factors has significant explanatory value for understanding processes associated with the co-occurrence of AOD use and sexual risk behavior outcomes. This study evaluated simultaneously the mediating role of AOD-sex related expectancies and inhibition conflict on antecedents of AOD use and SRBs including sexual sensation-seeking and peer norms for condom use. The sample was drawn from the Enhancing My Personal Options While Evaluating Risk (EMPOWER: Jonathan Tubman, PI), data set (N = 396; aged 12-18 years). Measures used in the study included Sexual Sensation-Seeking Scale, Inhibition Conflict for Condom Use, Risky Sex Scale. All relevant measures had well-documented psychometric properties. A global assessment of alcohol, drug use and sexual risk behaviors was used. Results demonstrated that AOD-sex related expectancies mediated the influence of sexual sensation-seeking on the co-occurrence of alcohol and other drug use and sexual risk behaviors. The evaluation of the integrative model also revealed that sexual sensation-seeking was positively associated with peer norms for condom use. Also, peer norms predicted inhibition conflict among this sample of multi-problem youth. This dissertation research identified mechanisms of risk and protection associated with the co-occurrence of AOD use and SRBs among a multi-problem sample of adolescents receiving treatment for alcohol or drug use and related problems. This study is informative for adolescent-serving programs that address those individual and contextual characteristics that enhance treatment efficacy and effectiveness among adolescents receiving substance use and related problems services.
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The Amundsen Sea Embayment (ASE) drains approximately 35% of the West Antarctic Ice Sheet (WAIS) and is one of the most rapidly changing parts of the cryosphere. In order to predict future ice-sheet behaviour, modellers require long-term records of ice-sheet melting to constrain and build confidence in their simulations. Here, we present detailed marine geological and radiocarbon data along three palaeo-ice stream tributary troughs in the western ASE to establish vital information on the timing of deglaciation of the WAIS since the Last Glacial Maximum (LGM). We have undertaken multi-proxy analyses of the cores (core description, shear strength, x-radiographs, magnetic susceptibility, wet bulk density, total organic carbon/nitrogen, carbonate content and clay mineral analyses) in order to: (1) characterise the sedimentological facies and depositional environments; and (2) identify the horizon(s) in each core that would yield the most reliable age for deglaciation. In accordance with previous studies we identify three key facies, which offer the most reliable stratigraphies for dating deglaciation by recording the transition from a grounded ice sheet to open marine environments. These facies are: i) subglacial, ii) proximal grounding-line, and iii) seasonal open-marine. In addition, we incorporate ages from other facies (e.g., glaciomarine diamictons deposited at some distance from the grounding line, such as glaciogenic debris flows and iceberg rafted diamictons and turbates) into our deglacial model. In total, we have dated 78 samples (mainly the acid insoluble organic (AIO) fraction, but also calcareous foraminifers), which include 63 downcore and 15 surface samples. Through careful sample selection prior to dating, we have established a robust deglacial chronology for this sector of the WAIS. Our data show that deglaciation of the western ASE was probably underway as early as 22,351 calibrated years before present (cal 44 yr BP), reaching the mid-shelf by 13,837 cal yr BP and the inner shelf to within c.10-12 km of the present ice shelf front between 12,618 and 10,072 cal yr BP. The deglacial steps in the western ASE broadly coincide with the rapid rises in sea-level associated with global meltwater pulses 1a and 1b, although given the potential dating uncertainty, additional, more precise ages are required before these findings can be fully substantiated. Finally, we show that the rate of ice-sheet retreat increased across the deep (up to1,600 m) basins of the inner shelf, highlighting the importance of reverse slope and pinning points in accelerated phases of deglaciation.
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This dissertation is a multi-level, cross-cultural study of women in leadership conducted with both macro-society data and individual-level data aggregated to the country level. The research questions are, “What macro and micro forces are hindering or advancing women into business or political leadership?” “How do these forces impact the level of women’s involvement in business and political leadership in a particular country?” Data was collected from 10 secondary sources, available for 213 countries, and includes about 300 variables for business leadership (N=115) and political leadership (N=181). To date, most women in leadership research has been Western- or US- based, and little rigorous empirical, multi-level research has been done across countries. The importance of cross-cultural studies on women in leadership stems from the potential to better understand why some countries have more women in positions of both business and political leadership; and the factors that affect women’s involvement in such positions in different countries. A “Levels of Women’s Participation in Leadership” country model is tested using cluster and discriminant analyses. Results indicate that the factors that affect women’s participation in leadership in countries with fewer women leaders are different from the factors that affect women’s participation in countries with high levels of participation. This dissertation proposes that initiatives to increase participation of women in leadership need to consider the relevant factors that significantly affect countries at certain Levels of Women’s Participation in Leadership.
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Viruses play a key role in the complex aetiology of bovine respiratory disease (BRD). Bovine viral diarrhoea virus 1 (BVDV-1) is widespread in Australia and has been shown to contribute to BRD occurrence. As part of a prospective longitudinal study on BRD, effects of exposure to BVDV-1 on risk of BRD in Australian feedlot cattle were investigated. A total of 35,160 animals were enrolled at induction (when animals were identified and characteristics recorded), held in feedlot pens with other cattle (cohorts) and monitored for occurrence of BRD over the first 50 days following induction. Biological samples collected from all animals were tested to determine which animals were persistently infected (PI) with BVDV-1. Data obtained from the Australian National Livestock Identification System database were used to determine which groups of animals that were together at the farm of origin and at 28 days prior to induction (and were enrolled in the study) contained a PI animal and hence to identify animals that had probably been exposed to a PI animal prior to induction. Multi-level Bayesian logistic regression models were fitted to estimate the effects of exposure to BVDV-1 on the risk of occurrence of BRD.Although only a total of 85 study animals (0.24%) were identified as being PI with BVDV-1, BVDV-1 was detected on quantitative polymerase chain reaction in 59% of cohorts. The PI animals were at moderately increased risk of BRD (OR 1.9; 95% credible interval 1.0-3.2). Exposure to BVDV-1 in the cohort was also associated with a moderately increased risk of BRD (OR 1.7; 95% credible interval 1.1-2.5) regardless of whether or not a PI animal was identified within the cohort. Additional analyses indicated that a single quantitative real-time PCR test is useful for distinguishing PI animals from transiently infected animals.The results of the study suggest that removal of PI animals and/or vaccination, both before feedlot entry, would reduce the impact of BVDV-1 on BRD risk in cattle in Australian feedlots. Economic assessment of these strategies under Australian conditions is required. © 2016 Elsevier B.V.
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There is evidence that students benefit from teachers’ explicit fostering of metacognitive strategy knowledge (MSK). However, there is insufficient understanding about the effect of implicit promotion of MSK in regular school instruction. This study investigates the relationship between perceived characteristics of learning environments (social climate, support, autonomy, self-reflection) and students’ MSK. A representative cohort of students (Nt1 = 1,272/Nt2 = 1,126) in Grades 10 and 11 at schools at the upper secondary education level (ISCED Level 3A) in Switzerland participated in this two-wave longitudinal study. Multilevel analysis showed effects on both the individual and the class level. Students who experienced higher social integration showed a higher extent of MSK at the beginning of the school year than students who experienced less social integration. Perceived autonomy was also positively related to students’ MSK on the individual level. In contrast, the results showed a negative relationship between perceived self-reflection and students’ MSK. On the class level, there was a negative relationship between self-reflection and students’ MSK. Teachers’ support did not correlate with students’ MSK on either the individual or the class level. Implications of these results for education and further studies are discussed. (DIPF/Orig.)
Resumo:
The Stockholm Programme, allied to the Lisbon Treaty, heralds a new era of development of the EU provisions on cross-border law enforcement. The focus is shifting from the ongoing internal EU developments to the external relations of the EU. Many North African countries have had long legal relationships with the EU through the Euro-Mediterranean Partnerships. A number of these partnership agreements make express references, at the political level, to the development of cross-border law enforcement provision, as is the case of Morocco and Algeria with regard to drug trafficking and manufacture, or the lengthy references by Egypt to many of the crimes of interest to the EU’s own law enforcement legal framework. Algeria is currently focusing on modernising their own police forces, with both Algeria and Tunisia, reforming their criminal judicial frameworks. Another key player, Libya, currently has no legal agreements with the EU, and at least until the recent conflict, maintained an observer status in the Euro-Mediterranean process. At a practitioner level, the European Police College (CEPOL) is currently involved in the Euromed Police II programme. Clearly momentum is developing, both within the EU and from a number of Euro-Med North African countries to develop closer law enforcement co-operation. This may well develop further with the recent changes in governments of a number of North African countries. The EU approach in the Police and Judicial Cooperation in Criminal Matters (PJCCM) policy area is to develop a legal framework upon which EU cross-border law enforcement will be based. The current EU cross-border law enforcement framework is the product of many years of multi-level negotiations. Challenges will arise as new countries from different legal and policing traditions will attempt to engage with already highly detailed legal and practice frameworks. The shared European legal traditions will not necessarily be reflected in the North African countries. This chapter critically analyses, from an EU legal perspective the problems and issues that will be encountered as the EU’s North African partner countries attempt to articulate into the existing, and still developing EU cross-border law enforcement framework.
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Multi-element analyses of sediment samples from the Santos-Cubatão Estuarine System were carried out to investigate the spatial and seasonal variability of trace-element concentrations. The study area contains a rich mangrove ecosystem that is a habitat for tens of thousands of resident and migratory birds, some of them endangered globally. Enrichments of metals in fine-grained surface sediments are, in decreasing order, Hg, Mn, La, Ca, Sr, Cd, Zn, Pb, Ba, Cu, Cr, Fe, Nb, Y, Ni and Ga, relative to pre-industrial background levels. The maximum enrichment ranged from 49 (Hg) to 3.1 (Ga). Mercury concentrations were greater in the Cubatão river than in other sites, while the other elements showed greater concentrations in the Morrão river. Concentrations of Mn were significantly greater in winter and autumn than in summer and spring. However, other elements (e.g. Cd and Pb) showed the opposite, with greater concentrations in summer and spring. This study suggests that seasonal changes in physical and chemical conditions may affect the degree of sediment enrichment and therefore make the assessment of contamination difficult. Consequently, these processes need to be considered when assessing water quality and the potential contamination of biota.
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Background: Group I introns are found in the nuclear small subunit ribosomal RNA gene (SSU rDNA) of some species of the genus Porphyra (Bangiales, Rhodophyta). Size polymorphisms in group I introns has been interpreted as the result of the degeneration of homing endonuclease genes (HEG) inserted in peripheral loops of intron paired elements. In this study, intron size polymorphisms were characterized for different Porphyra spiralis var. amplifolia (PSA) populations on the Southern Brazilian coast, and were used to infer genetic relationships and genetic structure of these PSA populations, in addition to cox2-3 and rbcL-S regions. Introns of different sizes were tested qualitatively for in vitro self-splicing. Results: Five intron size polymorphisms within 17 haplotypes were obtained from 80 individuals representing eight localities along the distribution of PSA in the Eastern coast of South America. In order to infer genetic structure and genetic relationships of PSA, these polymorphisms and haplotypes were used as markers for pairwise Fst analyses, Mantel's test and median joining network. The five cox2-3 haplotypes and the unique rbcL-S haplotype were used as markers for summary statistics, neutrality tests Tajima's D and Fu's Fs and for median joining network analyses. An event of demographic expansion from a population with low effective number, followed by a pattern of isolation by distance was obtained for PSA populations with the three analyses. In vitro experiments have shown that introns of different lengths were able to self-splice from pre-RNA transcripts. Conclusion: The findings indicated that degenerated HEGs are reminiscent of the presence of a full-length and functional HEG, once fixed for PSA populations. The cline of HEG degeneration determined the pattern of isolation by distance. Analyses with the other markers indicated an event of demographic expansion from a population with low effective number. The different degrees of degeneration of the HEG do not refrain intron self-splicing. To our knowledge, this was the first study to address intraspecific evolutionary history of a nuclear group I intron; to use nuclear, mitochondrial and chloroplast DNA for population level analyses of Porphyra; and intron size polymorphism as a marker for population genetics.
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Accumulating evidence suggests that Team-member exchange (TMX) influences employee work attitudes and behaviours separately from the effects of leader-member exchange (LMX). In particular, little is known of the effect of LMX differentiation (in-group versus out-group) as a process of social exhange that can, in turn, affect TMX quality. To explore this phenomenon, this chapter presents a multi-level model of TMX in organizations, which incorporates LMX differentiation, team identification, team member affect at the individual level, and fairness of LMX differentiation and affective climate at the group-level. We conclude with a discussion of the implications of our model for theory, research, and practice.
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Squeezed light is of interest as an example of a non-classical state of the electromagnetic field and because of its applications both in technology and in fundamental quantum physics. This review concentrates on one aspect of squeezed light, namely its application in atomic spectroscopy. The general properties, detection and application of squeezed light are first reviewed. The basic features of the main theoretical methods (master equations, quantum Langevin equations, coupled systems) used to treat squeezed light spectroscopy are then outlined. The physics of squeezed light interactions with atomic systems is dealt with first for the simpler case of two-level atoms and then for the more complex situation of multi-level atoms and multi-atom systems. Finally the specific applications of squeezed light spectroscopy are reviewed.
Resumo:
In this paper, we investigate the effects of societal values and life stage on subordinate influence ethics. Based on the evolving crossvergence theory of macro-level predictors of values evolution, we demonstrate the applicability of crossvergence theory in the micro-level context. Furthermore, our study provides the first empirical multi-level analysis of influence ethics utilizing a multi pie-country sample. Thus, we illustrate how the breath of crossvergence can be expanded to provide a multi-level theoretical foundation of values and behavior evolution across cultures. Specifically, we integrate micro-level life stage theory and macro-level societal culture theory to concurrently assess the contributions of each theory in explaining subordinate influence ethics across the diverse societies of Brazil. China, Germany and the U.S. Consistent with previous research, we found significant societal differences in influence ethics. However, we also found that life stage theory played a significant role in understanding influence ethics. Thus, our findings expand the crossvergence perspective on societal change, indicating that key micro-level predictors (e.g., life stage) should be included in cross-cultural research. (C) 2009 Elsevier Inc. All rights reserved.
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Weiss and Isen have provided many supportive comments about the multi-level perspective, but also found limitations. Isen noted the importance of integrating affect, cognition, and motivation. Weiss commented similarly that the model lacked an integrating “thread.” He suggested that, to be truly multilevel, each level should constrain processes at other levels, and also provide guidance for the development of new concepts. Weiss also noted that the focus on biological processes was a strength of the model. I respond by suggesting that these very biological processes may constitute the “missing” thread. To illustrate this, I discuss some of the recent research on emotions in organizational settings, and argue that biology both constrains and guides theory at each level of the model. Based on this proposition, I revisit each of the five levels in the model, to demonstrate how this integration can be accomplished in this fashion. Finally, I address two additional points: aggregation bias, and the possibility of extending the model to include higher levels of industry and region.
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Issues concerning the influence of attachment characteristics on own and partner's disclosure were addressed using a sample of 113 couples in medium-term dating relationships. Individual differences in attachment were assessed in terms of relationship anxiety and avoidance. Disposition to disclose was assessed using questionnaire measures of self-disclosure, relationship-focused disclosure, and the ability to elicit disclosure from the partner; in addition, structured diaries were used to assess aspects of disclosure (amount, intimacy, emotional tone, and satisfaction) in the context of couples' everyday interactions. Couple-level analyses showed that avoidance strongly predicted dispositional measures of disclosure, whereas anxiety (particularly partner's anxiety) was related to negative evaluations of everyday interactions. Interactive effects of attachment dimensions and gender were also obtained, highlighting the complexity of communication behavior. The results are discussed in terms of the goals and strategies associated with working models of attachment.