833 resultados para Negative dimensions
Resumo:
Invasive species are an excellent opportunity to think about the nature society desires, particularly in the face of global changes. Nature and human views of nature are rapidly evolving; our approach to bio- logical invasions through biosecurity institutions and land management policies must evolve in tandem with these changes. We review three dimensions that are insufficiently addressed. First, biological inva- sions are culturally shaped and interpreted. Humans play a major role in the movement and nurturing of alien life, and esthetics, perception, and emotion are deeply implicated in the management of invasive species. What people fear or regret with invasive species are not their effects on nature per se, but their effects on a particular desired nature, and policymaking must reflect this. Second, biological invasions are not restricted to negative impacts. Invasions take place in landscapes where many natural condi- tions have been altered, so policy tools must recognize that invasive species are a functional, structural, and compositional part of transformed ecosystems. In some cases, native species benefit from changes in resource availability caused by invasions or from protections provided by an invasive plant. Finally, invasive species can help ecosystems and people to adapt to global change by maintaining ecosystem processes such as productivity, carbon storage, and nutrient cycling in a context of climate change or land cover transformations. While recognition is growing among ecologists that novel, invaded ecosystems have value, and while the on-the-ground application of biosecurity policies has of necessity adjusted to local contexts and other agendas, invasion biology could aid policymaking by better addressing the three complexities inherent in the three dimensions highlighted above.
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Objective: To compare lower incisor dentoalveolar compensation and mandible symphysis morphology among Class I and Class III malocclusion patients with different facial vertical skeletal patterns. Materials and Methods: Lower incisor extrusion and inclination, as well as buccal (LA) and lingual (LP) cortex depth, and mandibular symphysis height (LH) were measured in 107 lateral cephalometric x-rays of adult patients without prior orthodontic treatment. In addition, malocclusion type (Class I or III) and facial vertical skeletal pattern were considered. Through a principal component analysis (PCA) related variables were reduced. Simple regression equation and multivariate analyses of variance were also used. Results: Incisor mandibular plane angle (P < .001) and extrusion (P = .03) values showed significant differences between the sagittal malocclusion groups. Variations in the mandibular plane have a negative correlation with LA (Class I P = .03 and Class III P = .01) and a positive correlation with LH (Class I P = .01 and Class III P = .02) in both groups. Within the Class III group, there was a negative correlation between the mandibular plane and LP (P = .02). PCA showed that the tendency toward a long face causes the symphysis to elongate and narrow. In Class III, alveolar narrowing is also found in normal faces. Conclusions: Vertical facial pattern is a significant factor in mandibular symphysis alveolar morphology and lower incisor positioning, both for Class I and Class III patients. Short-faced Class III patients have a widened alveolar bone. However, for long-faced and normal-faced Class III, natural compensation elongates the symphysis and influences lower incisor position.
Resumo:
Des études récentes suggèrent que le perfectionnisme est un phénomène multidimensionnel avec des composantes néfastes, mais aussi des éléments positifs, au bien-être psychosocial. Une étude a été élaborée afin de comparer la prévalence de ces éléments chez les garçons et les filles surdoués. Quarante-neuf enfants âgés de 7 à 11 ans ont rapporté leurs attitudes perfectionnistes, appartenant à deux dimensions du phénomène : le perfectionnisme orienté ver soi et le perfectionnisme socialement prescrit. Contrairement à nos attentes, les résultats révèlent que la prévalence des deux dimensions de perfectionnisme ne diffère pas de manière significative entre les filles et les garçons surdoués. Une analyse des résultats et de leurs implications pour de futures recherches est offerte.
Resumo:
Purpose in life predicts both health and longevity suggesting that the ability to find meaning from life’s experiences, especially when confronting life’s challenges, may be a mechanism underlying resilience. Having purpose in life may motivate reframing stressful situations to deal with them more productively, thereby facilitating recovery from stress and trauma. In turn, enhanced ability to recover from negative events may allow a person to achieve or maintain a feeling of greater purpose in life over time. In a large sample of adults (aged 36-84 years) from the MIDUS study (Midlife in the U.S., http://www.midus.wisc.edu/), we tested whether purpose in life was associated with better emotional recovery following exposure to negative picture stimuli indexed by the magnitude of the eyeblink startle reflex (EBR), a measure sensitive to emotional state. We differentiated between initial emotional reactivity (during stimulus presentation) and emotional recovery (occurring after stimulus offset). Greater purpose in life, assessed over two years prior, predicted better recovery from negative stimuli indexed by a smaller eyeblink after negative pictures offset, even after controlling for initial reactivity to the stimuli during the picture presentation, gender, age, trait affect, and other well-being dimensions. These data suggest a proximal mechanism by which purpose in life may afford protection from negative events and confer resilience is through enhanced automatic emotion regulation after negative emotional provocation.
Resumo:
We study the properties of the lower bound on the exchange-correlation energy in two dimensions. First we review the derivation of the bound and show how it can be written in a simple density-functional form. This form allows an explicit determination of the prefactor of the bound and testing its tightness. Next we focus on finite two-dimensional systems and examine how their distance from the bound depends on the system geometry. The results for the high-density limit suggest that a finite system that comes as close as possible to the ultimate bound on the exchange-correlation energy has circular geometry and a weak confining potential with a negative curvature. (c) 2009 Elsevier B.V. All rights reserved.
Resumo:
Apesar da pesquisa em confiança interorganizacional e sua relação com performance ter sido conduzida sob as perspectivas da Teoria de Custos de Transação, Teoria das Trocas Sociais e Canais de Marketing, três importantes lacunas na literatura requerem investigação. Primeiro, está em andamento um debate conceitual sobre a multi-dimensionalidade da confiança, e como ela deve ser operacionalizada e medida, e que se divide em três correntes de pensamento - um construto multidimensional definido por dimensões não dominantes, um construto baseado em duas dimensões dominantes (afetiva e calculativa), ou um construto unidimensional. Segundo, existe ambiguidade em como as dimensões da confiança são definidas, levando a artefatos de equivalência nas escalas e resultados contraditórios. Terceiro, as diferentes percepções que compradores e fornecedores podem ter em cada dimensão da confiança e seu impacto na performance logística ainda não estão claros. Esta pesquisa empírica examina a confiança nas relações entre compradores e fornecedores no setor de logística no Brasil, através de duas amostras e estudos independentes: um examina a percepção dos compradores e o outro examina a dos fornecedores. Em seguida, os dois estudos são comparados para determinar as diferentes perspectivas da confiança e as implicações na performance logística. A análise multivariada mostrou que a confiança parece estar presente nas relações interorganizacionais, e é a percepção do comprador que possui maior relação com a performance logística. Ao mesmo tempo, compradores percebem fornecedores de forma mais negativa nas dimensões mensuráveis (competência e performance), enquanto não foram encontradas diferenças nos aspectos sociais (honestidade e benevolência), o que pode ser resultado do ambiente e cultura pesquisados. As análises mostraram que, apesar da confiança poder ser definida como um construto multidimensional, ela deve ser operacionalizada como um construto unidimensional direcionado pela competência e credibilidade. Este estudo contribui para a prática sugerindo formas de aumentar a confiança interorganizacional para aumento da performance.
Resumo:
The well-known D-dimensional Feynman integrals were shown, by Halliday and Ricotta, to be capable of undergoing analytic continuation into the domain of negative values for the dimension of space-time. Furthermore, this could be identified with Grassmannian integration in positive dimensions. From this possibility follows the concept of negative-dimensional integration for loop integrals in field theories. Using this technique, we evaluate three two-loop three-point scalar integrals, with five and six massless propagators, with specific external kinematic configurations (two legs on-shell), and four three-loop two-point scalar integrals. These results are given for arbitrary exponents of propagators and dimension, in Euclidean space, and the particular cases compared to results published in the literature.
Resumo:
We examine two-component Gross-Pitaevskii equations with nonlinear and linear couplings, assuming self-attraction in one species and self-repulsion in the other, while the nonlinear inter-species coupling is also repulsive. For initial states with the condensate placed in the self-attractive component, a sufficiently strong linear coupling switches the collapse into decay (in the free space). Setting the linear-coupling coefficient to be time-periodic (alternating between positive and negative values, with zero mean value) can make localized states quasi-stable for the parameter ranges considered herein, but they slowly decay. The 2D states can then be completely stabilized by a weak trapping potential. In the case of the high-frequency modulation of the coupling constant, averaged equations are derived, which demonstrate good agreement with numerical solutions of the full equations. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
We derive an one-parameter family of consistency conditions to braneworlds in the Brans-Dicke gravity. The General Relativity case is recovered by taking a correct limit of the Brans-Dicke parameter. We show that it is possible to build a multiple AdS brane scenario in a six-dimensional bulk only if the brane tensions are negative. Besides, in the five-dimensional case, it is showed that no fine tuning is necessary between the bulk cosmological constant and the brane tensions, in contrast to the Randall-Sundrum model. Copyright © owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial- ShareAlike Licence.
Resumo:
Objective – To correlate facial type measurements of Caucasian individuals with transverse dimensions of normal occlusion arches. Methods – Twenty-one pairs of dental models were selected according to the following inclusion criteria: presence of all permanent teeth from 1 st molar to 1 st molar; normal occlusion; no prosthetic crowns; no previous orthodontic treatment and 2 mm or less of crow- dings or spacings. The cephalometric measurements of lateral cephalometric X-ray of the same individuals were taken and tabulat ed. To evaluate the repetition of arch measurements, paired Student’s t-test and Pearson's correlation coefficient were used. The r elationship between the measurements was analysed by using the Pearson’s correlation. Results – The repetition of the measurements showed high correlation and no systematic error. In the comparison between the measurements, a moderate negative correlation was observed b et- ween facial axis angle and the measurements Upper and Lower 6-6, whereas a positive correlation was observed between dentition height and the latter. Conclusion – It was observed a negative correlation between facial axis angle and upper and lower inter-molar distance as well as a positive correlation between dentition height and upper and lower inter-molar distance.
Resumo:
Trampling by human visitors to rocky shores is a known stressor on macroorganisms. However, the effects of trampling on rocky intertidal biofilm, a complex association of microorganisms of ecological importance in coastal communities, have not been quantified. We evaluated the impact of trampling frequency and intensity on total biomass of epilithic microalgae on intertidal rocky shores in the southeast of Brazil. There was a trend of increase in the variability of biomass of biofilm in function of intensity of trampling, but no significant effects emerged among trampling treatments. The low influence of trampling on biofilm might be a result of the small dimensions of the organisms coupled with their natural resilience and roughness of the substrate; the former preventing the removal of biofilm layers by shoes and facilitating their quick recovery. Our results provide insights for management and conservation of coastal ecosystems revealing a weaker impact of trampling on biofilm than that reported on macroorganisms. (C) 2012 Elsevier Ltd. All rights reserved.
Resumo:
OBJECTIVE: To assess the memory of various subdimensions of the birth experience in the second year postpartum, and to identify women in the first weeks postpartum at risk of developing a long-term negative memory. DESIGN, METHOD, OUTCOME MEASURES: New mothers' birth experience (BE) was assessed 48-96 hours postpartum (T1) by means of the SIL-Ger and the BBCI (perception of intranatal relationships); early postnatal adjustment (week 3 pp: T1(bis)) was also assessed. Then, four subgroups of women were defined by means of a cluster-analysis, integrating the T1/T1(bis) variables. To evaluate the memory of the BE, the SIL-Ger was again applied in the second year after childbirth (T2). First, the ratings of the SIL-Ger dimensions of T1 were compared to those at T2 in the whole sample. Then, the four subgroups were compared with respect to their ratings of the birth experience at T2 (correlations, ANOVAs and t-tests). RESULTS: In general, fulfillment, emotional adaptation, physical discomfort, and anxiety improve spontaneously over the first year postpartum, whereas in negative emotional experience, control, and time-going-slowly no shift over time is observed. However, women with a negative overall birth experience and a low level of perceived intranatal relationship at T1 run a high risk of retaining a negative memory in all of the seven subdimensions of the birth experience. CONCLUSIONS: Women at risk of developing a negative long-term memory of the BE can be identified at the time of early postpartum, when the overall birth experience and the perceived intranatal relationship are taken into account.
Resumo:
A common form of social regulation of an individual’s health behavior is social control. The contextual model of social control assumes that higher relationship quality goes along with more beneficial effects of social control on health behavior. This study examined potential differential moderating effects of different dimensions of relationship quality on the associations between positive and negative social control and smoking behavior and hiding smoking. The sample consisted of 144 smokers (n = 72 women; mean age = 31.78, SD = 10.04) with a nonsmoking partner. Positive and negative social control, dimensions of relationship quality consensus, cohesion and satisfaction, numbers of cigarettes smoked (NCS), hiding smoking (HS), and control variables were assessed at baseline. Four weeks later NCS and HS were assessed again. Only for smokers with high consensus, but not cohesion and satisfaction, a negative association between positive control and NCS emerged. Moreover, smokers with high consensus tended to report more HS when being positively and negatively socially controlled. This also emerged for cohesion and positive control. Satisfaction with the relationship did not display any interaction effects. This study’s results emphasize the importance of differentiating not only between positive and negative social control but also between different dimensions of relationship quality in order to gain a comprehensive understanding of the dynamics in romantic dyads with regard to social regulation of behavioral change.
Resumo:
The aim was to examine to what extent the dimensions of the BPS map the five factors derived from the PANSS in order to explore the level of agreement of these alternative dimensional approaches in patients with schizophrenia. 149 inpatients with schizophrenia spectrum disorders were recruited. Psychopathological symptoms were assessed with the Bern Psychopathology Scale (BPS) and the Positive and Negative Syndrome Scale (PANSS). Linear regression analyses were conducted to explore the association between the factors and the items of the BPS. The robustness of patterns was evaluated. An understandable overlap of both approaches was found for positive and negative symptoms and excitement. The PANSS positive factor was associated with symptoms of the affect domain in terms of both inhibition and disinhibition, the PANSS negative factor with symptoms of all three domains of the BPS as an inhibition and the PANSS excitement factor with an inhibition of the affect domain and a disinhibition of the language and motor domains. The results show that here is only a partial overlap between the system-specific approach of the BPS and the five-factor PANSS model. A longitudinal assessment of psychopathological symptoms would therefore be of interest.
Resumo:
Previous research suggests that hurt feelings can have powerful effects on individual and relational outcomes. This study examined a typology of hurtful events in couple relationships, together with integrative models predicting ongoing effects on victims and relationships. Participants were 224 students from introductory and third-year psychology classes, who completed open-ended and structured measures concerning an event in which a partner had hurt their feelings. By tailoring Leary et al.'s (1998) typology to the context of romantic relationships, five categories of hurtful events were proposed: active disassociation, passive disassociation, criticism, infidelity, and deception. Analyses assessing similarities and differences among the categories confirmed the utility of the typology. Structural equation modeling showed that longer-term effects on the victim were predicted by relationship anxiety and by the victim's immediate reactions to the event (negative emotions and self-perceptions; feelings of rejection and powerlessness). In contrast, ongoing effects on the relationship were predicted by avoidance, the victim's attributions and perceptions of offender remorse, and the victim's own behavior. The results highlight the utility of an integrated approach to hurt, incorporating emotional, cognitive, and behavioral responses, and dimensions of attachment security.