984 resultados para 126-787


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pyridinium tetrafluoroborate (C5H5NHBF4) and pyridinium hexafluorosilicate [(C5H5NH)2SiF6] have been prepared in good yields and high purity by the reaction of pyridinium poly(hydrogen fluoride) with oxides and acids of boron and silicon respectively. The salts have been characterised by melting points, IR, 1H and 19F NMR spectroscopy and chemical analysis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

- Background This study examined relationships between adiposity, physical functioning and physical activity. - Methods Obese (N=107) and healthy-weight (N=132) children aged 10-13 years underwent assessments of percent body fat (%BF, dual energy X-ray absorptiometry), knee extensor strength (KE, isokinetic dynamometry), cardiorespiratory fitness (CRF, peak oxygen uptake by cycle ergometry), physical health-related quality of life (HRQOL), worst pain intensity and walking capacity [six-minute walk (6MWT)]. Structural equation modelling was used to assess relationships between variables. - Results Moderate relationships were observed between %BF and 6MWT, KE strength corrected for mass and CRF relative to mass (r -.36 to -.69, P≤.007). Weak relationships were found between: %BF and physical HRQOL (r -.27, P=.008); CRF relative to mass and physical HRQOL (r -.24, P=.003); physical activity and 6MWT (r .17, P=.004). Squared multiple correlations showed that 29.6% variance in physical HRQOL was explained by %BF, pain and CRF relative to mass, while 28% variance in 6MWT was explained by %BF and physical activity. - Conclusions It appears that children with a higher body fat percentage have poorer KE strength, CRF and overall physical functioning. Reducing percent fat appears to be the best target to improve functioning. However, a combined approach to intervention, targeting reductions in body fat percentage, pain and improvements in physical activity and CRF may assist physical functioning.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The cattle tick Rhipicephalus microplus (formerly Boophilus microplus) is responsible for severe production losses to the cattle industry worldwide. It has long been known that different breeds of cattle can resist tick infestation to varying degrees; however, the mechanisms by which resistant cattle prevent heavy infestation are largely unknown. The aim of this study was to determine whether gene expression varied significantly between skin sampling sites (neck, chest and tail region), and whether changes in gene expression could be detected in samples taken at tick attachment sites (tick attached to skin sample) compared with samples taken from non-attachment sites (no tick attachment). We present here the results of an experiment examining the expression of a panel of forty-four genes in skin sections taken from Bos indicus (Brahman) cattle of known high resistance, and Bos taurus (Holstein-Friesian) cattle of known low resistance to the cattle tick. The forty-four genes chosen for this study included genes known to be involved in several immune processes, some structural genes, and some genes previously suggested to be of importance in tick resistance by other researchers. The expression of fifteen gene transcripts increased significantly in Holstein-Friesian skin samples at tick attachment sites. The higher expression of many genes involved in innate inflammatory processes in the Holstein-Friesian animals at tick attachment sites suggests this breed is exhibiting a non-directed pathological response to infestation. Of the forty-four genes analysed, no transcripts were detected in higher abundance at tick attachment sites in the Brahman cattle compared with similar samples from the Holstein-Friesian group, nor difference between attachment site and non-attachment site samples within the Brahman group. The results presented here suggest that the means by which these two cattle breeds respond to tick infestation differ and warrant further investigation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Redundant DNA can buffer sequence dependent structural deviations from an ideal double helix. Buffering serves a mechanistic function by reducing extraneous conformational effects which could interfere with readout or which would impose energetic constraints on evolution. It also serves an evolutionary function by allowing for gradual variations in conformation-dependent regulation of gene expression. Such gradualism is critical for the rate of evolution. The buffer structure concept provides a new interpretation for repetitive DNA and for exons and introns.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Including collaboration with industry members as an integral part of research activities is a relatively new approach to fisheries research. Earlier approaches to involving fishers in research usually involved compulsory accommodations of research, such as through compulsory observer programs, in which fishers were seen as subjects of rather than participants in research. This new approach brings with it significant potential benefits but also some unique issues both for the researchers and the participating industry members. In this paper we describe a research project involving the Queensland Coral Reef Finfish Fishery that originated from industry and community concerns about changes in marketing practices in an established commercial line fishery. A key aspect of this project was industry collaboration in all stages of the research, from formulation of objectives to assistance with interpretation of results. We discuss this research as a case study of some of the issues raised by collaboration between industry and research groups in fisheries research and the potential pitfalls and benefits of such collaborations for all parties. A dedicated liaison and extension strategy was a key element in the project to develop and maintain the relationships between fishers and researchers that were fundamental to the success of the collaboration. A major research benefit of the approach was the provision of information not available from other sources: 300 days of direct and unimpeded observation of commercial fishing by researchers; detailed catch and effort records from a further 126 fishing trips; and 53 interviews completed with fishers. Fishers also provided extensive operational information about the fishery as well as ongoing support for subsequent research projects. The time and resources required to complete the research in this consultative framework were greater than for more traditional, researcher-centric fisheries research, but the benefits gained far outweighed the costs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dispersal is a significant determinant of the pattern and process of invasions; however, weed dispersal distances are rarely described and descriptions of dispersal kernels are completely lacking for vertebrate-dispersed weeds. Here, we describe dispersal kernels generated by a native disperser, the endangered southern cassowary (Casuarius casuarius, L.) for an invasive, tropical rainforest plant, pond apple (Annona glabra, L.). Pond apple is primarily water-dispersed and is managed as such. We consider whether cassowary dispersal, as a numerically subordinate dispersal mode, provides an additional dispersal service that may modify the invasion process. In infested areas, pond apple seed was common in cassowary dung. Gut passage had no effect on the probability of single seed germination but deposition in clumps or as whole fruits reduced the probability of germination below that of single seeds. Gut passage times ranged from 65 to 1675 min. Combined with cassowary movement data, this resulted in estimated dispersal distances of 12.5-5212 m, with a median distance of 387 m (quartile range 112-787 m). Native frugivores can be effective dispersers of weeds in rainforest and even terrestrial dispersers can provide long-distance dispersal. Importantly, though pond apple might be expected to be almost entirely dispersed downstream and along the margins of aquatic and marine habitats, cassowaries provide dispersal upstream and between drainages, leading to novel dispersal outcomes. Even through the provision of small quantities of novel dispersal outcomes, subordinate dispersal modes can play a significant role in determining invasion pattern and influence the ultimate success of control programs by providing dispersal to locations unattainable via the primary mode.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The number of Finnish pupils attending special education has increased for more than a decade (Tilastokeskus 1999, 2000, 2001, 2003, 2004, 2005a, 2006b, 2007b, 2008b, 2008e, 2009b; Virtanen ja Ratilainen 1996). In the year 2007 nearly third of Finnish comprehensive school pupils took part in special needs education. According to the latest statistics, in the autumn of 2008 approximately 47 000 pupils have been admitted or transferred to special education and approximately 126 000 pupils received part-time special education during the 2007 - 2008 academic year. (Tilastokeskus 2008b, 2009b.) The Finnish special education system is currently under review. The Reform, both in legislation and in practice, began nationwide in the year 2008 (e.g. Special education strategy document, November 2007 and the development project Kelpo). The aim of the study was the statistical description of the Finnish special education system and on the other hand to gain a deeper understanding about the Finnish special education system and its quantitative increase, by analysis based on the nationwide statistical information. Earlier studies have shown that the growth in special education is affected by multiple independent variables and cannot be solely explained by the pupil characteristics. The statistical overview and analysis have been carried out in two parts. In the first part, the description and analysis were based on statistical time series from the academic year 1979 -1980 until 2008. While, in the second, more detailed description and analysis, based on comparable time series from 1995 to 2008 and from 2001-2002 to 2007-2008, is presented. Historical perspective was one part of this study. There was an attempt to find reasons explaining the observed growth in the special needs education from late 1960s to 2008. The majority of the research was based on the nationwide statistics information. In addition to this, materials including educational legislation literature, different kind of records of special education and preceding studies were also used to support the research. The main results of the study, are two statistical descriptions and time series analysis of the quantitative increase of the special needs education. Further, a summary of the plausible factors behind the special education system change and its quantitative increase, is presented. The conclusions coming from the study can be summarised as follows: the comparable statistical time series analysis suggests that the growth in special education after the year 1999 could be a consequence of the changes in the structure of special education and that new group of pupils have been directed to special needs education. Keywords: Special education, comprehensive school, description, statistics, change

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A pin-on-disc test configuration has been used to examine the formation of the strain-hardened projection, or wear lips, especially at the trailing edge of the pin during dry sliding of aluminium alloys against steel discs. The mechanism of formation of such wear lips is studied with the aid of optical and electron microscopes. The plastic deformation of the pin, growth and eventual removal of the wear lip as wear debris are elucidated. The size and shape of the wear lips in pins of different shapes, i.e. square, rectangular, triangular and circular cross-sections, are described.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The physicochemical and functional properties of flours from 25 Papua New Guinean and Australian sweetpotato cultivars were evaluated. The cultivars (white-, orange-, cream-, and purple-fleshed, and with dry matter, from 15 to 28 g/100 g), were obovate, oblong, elliptic, curved, irregular in shape, and essentially thin-cortexed (1-2 mm). Flour yield was less than 90 g/100 g solids, while starch, protein, amylose, water absorption and solubility indices, as well as total sugars, varied significantly (p < 0.05). Potassium, sodium, calcium, and phosphorus were the major minerals measured, and there were differences in the pasting properties, which showed four classes of shear-thinning and shear-thickening behaviours. Differential scanning calorimetry showed single-stage gelatinisation behaviour, with cultivar-dependent temperatures (61-84 degrees C) and enthalpies (12-27 J/g dry starch). Oval-, round- and angular-shaped granules were observed with a scanning electron microscope, while X-ray diffraction revealed an A-type diffraction pattern in the cultivars, with about 30% crystallinity. This study shows a wide range of sweetpotato properties, reported for the first time.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The stimulation technique has gained much importance in the performance studies of Concurrency Control (CC) algorithms for distributed database systems. However, details regarding the simulation methodology and implementation are seldom mentioned in the literature. One objective of this paper is to elaborate the simulation methodology using SIMULA. Detailed studies have been carried out on a centralised CC algorithm and its modified version. The results compare well with a previously reported study on these algorithms. Here, additional results concerning the update intensiveness of transactions and the degree of conflict are obtained. The degree of conflict is quantitatively measured and it is seen to be a useful performance index. Regression analysis has been carried out on the results, and an optimisation study using the regression model has been performed to minimise the response time. Such a study may prove useful for the design of distributed database systems.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hermann (Lazar Hirsch) Judey, born 1878 Riga and died 1959 New York; Olga Judey nee Fischmann, 1878-1929