190 resultados para Sample morphology


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Sampling design is critical to the quality of quantitative research, yet it does not always receive appropriate attention in nursing research. The current article details how balancing probability techniques with practical considerations produced a representative sample of Australian nursing homes (NHs). Budgetary, logistical, and statistical constraints were managed by excluding some NHs (e.g., those too difficult to access) from the sampling frame; a stratified, random sampling methodology yielded a final sample of 53 NHs from a population of 2,774. In testing the adequacy of representation of the study population, chi-square tests for goodness of fit generated nonsignificant results for distribution by distance from major city and type of organization. A significant result for state/territory was expected and was easily corrected for by the application of weights. The current article provides recommendations for conducting high-quality, probability-based samples and stresses the importance of testing the representativeness of achieved samples.

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The informal taxon ‘genus Chile’ of Brundin, based solely on pupal exuviae of a podonomine Chironomidae, has remained inadequately known for half a century. New collections reveal life associations, and provide molecular data to hypothesise a precise phylogenetic placement in the austral Podonominae. A densely sampled molecular phylogeny based on two nuclear and one mitochondrial DNA markers shows ‘genus Chile’ to be the sister group to Podonomopsis Brundin, 1966. Within Podonomopsis a clade of South American species is sister to all Australian species. We discuss how to rank such a sister group taxon and treat ‘genus Chile’ as a new subgenus Araucanopsis, subg. nov. with the new species, Podonomopsis (Araucanopsis) avelasse, sp. nov. from Chile and Argentina as genotype of the monotypic subgenus. We describe P. (A.) avelasse in all stages and provide an expanded diagnosis and description of Podonomopsis to include Araucanopsis. A dated biogeographic hypothesis (chronogram) infers the most recent common ancestor (tmcra) of expanded Podonomopsis at 95 million years ago (Mya) (68–122 Mya 95% highest posterior density), ‘core’ Podonomopsis at 83 Mya (58–108) and Australian Podonomopsis at 65 Mya (44–87). All dates are before the South America–Australia geological separation through Antarctica, supporting previous conclusions that the taxon distribution is ‘Gondwanan’ in origin. Podonomopsis, even as expanded here, remains unknown from New Zealand or elsewhere on extant Zealandia.

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The aim of this paper is to investigate the relationship between research and design through an applied example of how architects can approach the design for a building guided by data derived from morphological research. An Expert Focus Group consisting of nine leading architects and urban designers from Brisbane, Australia was given the task of testing this proposition. Analysis of the workshop outcomes are examined, and the design drawings of each participant are assessed to determine the relative congruence of the design proposals within the morphological commodity of the specific context. In addition, qualitative data, captured through verbal and written feedback is assessed highlighting the participants' observations and experiences of the workshop. This paper makes a contribution to the current debate within the field on the opportunities of integrating research with practice.

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The modern diet has become highly sweetened, resulting in unprecedented levels of sugar consumption, particularly among adolescents. While chronic long-term sugar intake is known to contribute to the development of metabolic disorders including obesity and type II diabetes, little is known regarding the direct consequences of long-term, binge-like sugar consumption on the brain. Because sugar can cause the release of dopamine in the nucleus accumbens (NAc) similarly to drugs of abuse, we investigated changes in the morphology of neurons in this brain region following short- (4 weeks) and long-term (12 weeks) binge-like sucrose consumption using an intermittent two-bottle choice paradigm. We used Golgi-Cox staining to impregnate medium spiny neurons (MSNs) from the NAc core and shell of short- and long-term sucrose consuming rats and compared these to age-matched water controls. We show that prolonged binge-like sucrose consumption significantly decreased the total dendritic length of NAc shell MSNs compared to age-matched control rats. We also found that the restructuring of these neurons resulted primarily from reduced distal dendritic complexity. Conversely, we observed increased spine densities at the distal branch orders of NAc shell MSNs from long-term sucrose consuming rats. Combined, these results highlight the neuronal effects of prolonged binge-like intake of sucrose on NAc shell MSN morphology.

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Morphology-controlled bilayer TiO2 nanostructures consisting of one-dimensional (1D) nanowire bottom arrays and a three-dimensional (3D) dendritic microsphere top layer were synthesized via a one-step hydrothermal method. These novel 1D-3D bilayer photoanodes demonstrated the highest energy conversion efficiency of 7.2% for rutile TiO2 dye-sensitized solar cells to date, with TiCl4 post-treatment.

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Oriented, single-crystalline, one-dimensional (1D) TiO2 nanostructures would be most desirable for providing fascinating properties and features, such as high electron mobility or quantum confinement effects, high specific surface area, and even high mechanical strength, but achieving these structures has been limited by the availability of synthetic techniques. In this study, a concept for precisely controlling the morphology of 1D TiO2 nanostructures by tuning the hydrolysis rate of titanium precursors is proposed. Based on this innovation, oriented 1D rutile TiO2 nanostructure arrays with continually adjustable morphologies, from nanorods (NRODs) to nanoribbons (NRIBs), and then nanowires (NWs), as well as the transient state morphologies, were successfully synthesized. The proposed method is a significant finding in terms of controlling the morphology of the 1D TiO2 nano-architectures, which leads to significant changes in their band structures. It is worth noting that the synthesized rutile NRIBs and NWs have a comparable bandgap and conduction band edge height to those of the anatase phase, which in turn enhances their photochemical activity. In photovoltaic performance tests, the photoanode constructed from the oriented NRIB arrays possesses not only a high surface area for sufficient dye loading and better light scattering in the visible light range than for the other morphologies, but also a wider bandgap and higher conduction band edge, with more than 200% improvement in power conversion efficiency in dye-sensitized solar cells (DSCs) compared with NROD morphology.

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Reticulated porous Ti3AlC2 ceramic, a member of the MAX-phase family (Mn+1AXn phases, where M is an early transition metal, A is an A-group element, and X is carbon and/or nitrogen), was prepared from the highly dispersed aqueous suspension by a replica template method. Through a cathodic electrogeneration method, nanocrystalline catalytic CeO2 coatings were deposited on the conductive porous Ti 3AlC2 supports. By adjusting the pH value and cathodic deposition current, coatings exhibiting nanocellar, nanosheets-like, or bubble-free morphologies can be obtained. This work expects to introduce a novel practically feasible material system and a catalytic coating preparation technique for gas exhaust catalyst devices.

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This study investigates the morphology, microstructure and surface composition of Diesel engine exhaust particles. The state of agglomeration, the primary particle size and the fractal dimension of exhaust particles from petroleum Diesel (petrodiesel) and biodiesel blends from microalgae, cotton seed and waste cooking oil were investigated by means of high resolution transmission electron microscopy. With primary particle diameters between 12-19 nm, biodiesel blend primary particles are found to be smaller than petrodiesel ones (21±2 nm). Also it was found that soot agglomerates from biodiesels are more compact and spherical, as their fractal dimensions are higher, e.g. 2.2±0.1 for 50% algae biodiesel compared to 1.7±0.1 for petrodiesel. In addition, analysis of the chemical composition by means of x-ray photoelectron spectroscopy revealed an up to a factor of two increased oxygen content on the primary particle surface for biodiesel. The length, curvature and distance of graphene layers were measured showing a greater structural disorder for biodiesel with shorter fringes of higher tortuosity. This change in carbon chemistry may reflect the higher oxygen content of biofuels. Overall, it seems that the oxygen content in the fuels is the underlying reason for the observed morphological change in the resulting soot particles.

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The assembly of influenza A virus at the plasma membrane of infected cells leads to release of enveloped virions that are typically round in tissue culture-adapted strains but filamentous in strains isolated from patients. The viral proteins hemagglutinin (HA), neuraminidase (NA), matrix protein 1 (M1), and M2 ion channel all contribute to virus assembly. When expressed individually or in combination in cells, they can all, under certain conditions, mediate release of membrane-enveloped particles, but their relative roles in virus assembly, release, and morphology remain unclear. To investigate these roles, we produced membrane-enveloped particles by plasmid-derived expression of combinations of HA, NA, and M proteins (M1 and M2) or by infection with influenza A virus. We monitored particle release, particle morphology, and plasma membrane morphology by using biochemical methods, electron microscopy, electron tomography, and cryo-electron tomography. Our data suggest that HA, NA, or HANA (HA plus NA) expression leads to particle release through nonspecific induction of membrane curvature. In contrast, coexpression with the M proteins clusters the glycoproteins into filamentous membrane protrusions, which can be released as particles by formation of a constricted neck at the base. HA and NA are preferentially distributed to differently curved membranes within these particles. Both the budding intermediates and the released particles are morphologically similar to those produced during infection with influenza A virus. Together, our data provide new insights into influenza virus assembly and show that the M segment together with either of the glycoproteins is the minimal requirement to assemble and release membrane-enveloped particles that are truly virus-like.

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The 6-item Kessler Psychological Distress Scale (K6; Kessler et al., 2002) is a screener for psychological distress that has robust psychometric properties among adults. Given that a significant proportion of adolescents experience mental illness, there is a need for measures that accurately and reliably screen for mental disorders in this age group. This study examined the psychometric properties of the K6 in a large general population sample of adolescents (N = 4,434; mean age = 13.5 years; 44.6% male). Factor analyses were conducted to examine the dimensionality of the K6 in adolescents and to investigate sex-based measurement invariance. This study also evaluated the K6 as a predictor of scores on the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997). The K6 demonstrated high levels of internal consistency, with the 6 items loading primarily on 1 factor. Consistent with previous research, females reported higher mean levels of psychological distress when compared with males. The identification of sex-based measurement noninvariance in the item thresholds indicated that these mean differences most likely represented reporting bias in the K6 items rather than true differences in the underlying psychological distress construct. The K6 was a fair to good predictor of abnormal scores on the SDQ, but predictive utility was relatively low among males. Future research needs to focus on refining and augmenting the K6 scale to maximize its utility in adolescents. (PsycINFO Database Record (c) 2015 APA, all rights reserved)