1,362 research outputs found
Feasibility study of resistance welding of aluminum alloys, stainless steel, and titanium in a hard vacuum Final report, Jun. 27, 1967 - Feb. 29, 1968
Tensile strength and X ray analysis of resistance spot welded aluminum and stainless steel alloy
Styles of Farming and Farming Subcultures: Appropriate concepts for Australian rural sociology?
The general understanding of the
farming subculture concept is that the
primary motivation of farmers is their
notion of good farm management. Such
a social construction will vary between
different groups of farmers, such as
exist in different commodities, in
different regions, and possibly within
commodities and regions
Intensity-dependent reductions in resting blood pressure following short-term isometric exercise training
To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMGpeak (~23%MVC, maximum voluntary contraction, or 30%EMGpeak (~34%MVC)] or control group; 3 weeks of IET at 30%EMGpeak resulted in significant reductions in resting mean arterial pressure (e.g. −3.9 ± 1.0 mmHg, P 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMGpeak and 30%EMGpeak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible
The stable oxygen isotope ratio of resin extractable phosphate derived from fresh cattle faeces
Phosphorus losses from agriculture pose an environmental threat to watercourses. A new approach using the stable oxygen isotope ratio of oxygen in phosphate (δ18OPO4 value) may help elucidate some phosphorus sources and cycling. Accurately determined and isotopically distinct source values are essential for this process. The δ18OPO4 values of animal wastes have, up to now, received little attention.
Methods
Phosphate (PO4) was extracted from cattle faeces using anion resins and the contribution of microbial PO4 was assessed. The δ18OPO4 value of the extracted PO4 was measured by precipitating silver phosphate and subsequent analysis on a thermal conversion elemental analyser at 1400°C, with the resultant carbon monoxide being mixed with a helium carrier gas passed through a GC column into a mass spectrometer. Faecal water oxygen isotope ratios (δ18OH2O values) were determined on a dual-inlet mass spectrometer through a process of headspace carbon dioxide equilibration with water samples.
Results
Microbiological results indicated that much of extracted PO4 was not derived directly from the gut fauna lysed during the extraction of PO4 from the faeces. Assuming that the faecal δ18OH2O values represented cattle body water, the predicted pyrophosphatase equilibrium δ18OPO4 (Eδ18OPO4) values ranged between +17.9 and +19.9‰, while using groundwater δ18OH2O values gave a range of +13.1 to +14.0‰. The faecal δ18OPO4 values ranged between +13.2 and +15.3‰.
Conclusions
The fresh faecal δ18OPO4 values were equivalent to those reported elsewhere for agricultural animal slurry. However, they were different from the Eδ18OPO4 value calculated from the faecal δ18OH2O value. Our results indicate that slurry PO4 is, in the main, derived from animal faeces although an explanation for the observed value range could not be determined
Fourier transform for quantum -modules via the punctured torus mapping class group
We construct a certain cross product of two copies of the braided dual
of a quasitriangular Hopf algebra , which we call the elliptic
double , and which we use to construct representations of the punctured
elliptic braid group extending the well-known representations of the planar
braid group attached to . We show that the elliptic double is the universal
source of such representations. We recover the representations of the punctured
torus braid group obtained in arXiv:0805.2766, and hence construct a
homomorphism to the Heisenberg double , which is an isomorphism if is
factorizable.
The universal property of endows it with an action by algebra
automorphisms of the mapping class group of the
punctured torus. One such automorphism we call the quantum Fourier transform;
we show that when , the quantum Fourier transform
degenerates to the classical Fourier transform on as .Comment: 12 pages, 1 figure. Final version, to appear in Quantum Topolog
Loss of MITF expression during human embryonic stem cell differentiation disrupts retinal pigment epithelium development and optic vesicle cell proliferation
Microphthalmia-associated transcription factor (MITF) is a master regulator of pigmented cell survival and differentiation with direct transcriptional links to cell cycle, apoptosis and pigmentation. In mouse, Mitf is expressed early and uniformly in optic vesicle (OV) cells as they evaginate from the developing neural tube, and null Mitf mutations result in microphthalmia and pigmentation defects. However, homozygous mutations in MITF have not been identified in humans; therefore, little is known about its role in human retinogenesis. We used a human embryonic stem cell (hESC) model that recapitulates numerous aspects of retinal development, including OV specification and formation of retinal pigment epithelium (RPE) and neural retina progenitor cells (NRPCs), to investigate the earliest roles of MITF. During hESC differentiation toward a retinal lineage, a subset of MITF isoforms was expressed in a sequence and tissue distribution similar to that observed in mice. In addition, we found that promoters for the MITF-A, -D and -H isoforms were directly targeted by Visual Systems Homeobox 2 (VSX2), a transcription factor involved in patterning the OV toward a NRPC fate. We then manipulated MITF RNA and protein levels at early developmental stages and observed decreased expression of eye field transcription factors, reduced early OV cell proliferation and disrupted RPE maturation. This work provides a foundation for investigating MITF and other highly complex, multi-purposed transcription factors in a dynamic human developmental model syste
Modeling Concurrency in Parallel Debugging
We propose a description language, Data Path Expressions (DPEs), for modeling the behavior of parallel programs. We have designed DPEs as a high-level debugging language, where the debugging paradigm is for the programmer to describe the expected program behavior and for the debugger to compare the actual program behavior during execution to detect program errors. We classify DPEs into five subclasses according to syntactic criteria, and characterize their semantics in terms of a hierarchy of extended Petri Net models. The characterization demonstrates the power of DPEs for modeling (true) concurrency. We also present predecessor automata as a mechanism for implementing the third subclass of DPEs, which expresses bounded parallelism. Predecessor automata extend finite state automata to recognize or generate partial ordering graphs as well as strings, and provide efficient event recognizers for parallel debugging. We briefly describe the application of DPEs race conditions, deadlock and starvation
Tauiwi general practitioners explanations of Maori health: Colonial relations in primary healthcare in Aotearoa/New Zealand?
This paper reports initial findings from qualitative research investigating how general practitioners talk about Maori health. Transcripts of semi-structured interviews with 25 general practitioners from urban Auckland were subjected to critical discursive analyses. Through this process of intensive, analytic reading, interpretative repertoires – patterns of words and images about a particular topic – were identified. This paper presents the main features of one such repertoire, termed Maori Morbidity, that the general practitioners used in accounting for poor Maori health status. Our participants were drawing upon a circumscribed pool of ideas and explaining the inequalities in health between Maori and Tauiwi in ways that gave primacy to characteristics of Maori and their culture. We discuss the implications of this conclusion for relations between Maori patients and Tauiwi doctors in primary healthcare settings
Vancomycin AUC/MIC ratio and 30-day mortality in patients with Staphylococcus aureus bacteremia
A ratio of the vancomycin area under the concentration-time curve to the MIC (AUC/MIC) of ≥ 400 has been associated with clinical success when treating Staphylococcus aureus pneumonia, and this target was recommended by recently published vancomycin therapeutic monitoring consensus guidelines for treating all serious S. aureus infections. Here, vancomycin serum trough levels and vancomycin AUC/MIC were evaluated in a "real-world" context by following a cohort of 182 patients with S. aureus bacteremia (SAB) and analyzing these parameters within the critical first 96 h of vancomycin therapy. The median vancomycin trough level at this time point was 19.5 mg/liter. There was a significant difference in vancomycin AUC/MIC when using broth microdilution (BMD) compared with Etest MIC (medians of 436.1 and 271.5, respectively; P373, derived using classification and regression tree analysis, was associated with reduced mortality (P=0.043) and remained significant in a multivariable model. This study demonstrated that we obtained vancomycin trough levels in the target therapeutic range early during the course of therapy and that obtaining a higher vancomycin AUC/MIC (in this case, >373) within 96 h was associated with reduced mortality. The MIC test method has a significant impact on vancomycin AUC/MIC estimation. Clinicians should be aware that the current target AUC/MIC of ≥400 was derived using the reference BMD method, so adjustments to this target need to be made when calculating AUC/MIC ratio using other MIC testing methods. Copyrigh
Transformational capacity and the influence of place and identity
Climate change is altering the productivity of natural resources with far-reaching implications for those who depend on them. Resource-dependent industries and communities need the capacity to adapt to a range of climate risks if they are to remain viable. In some instances, the scale and nature of the likely impacts means that transformations of function or structure will be required. Transformations represent a switch to a distinct new system where a different suite of factors become important in the design and implementation of response strategies. There is a critical gap in knowledge on understanding transformational capacity and its influences. On the basis of current knowledge on adaptive capacity we propose four foundations for measuring transformational capacity: (1)how risks and uncertainty are managed, (2)the extent of skills in planning, learning and reorganizing, (3)the level of financial and psychological flexibility to undertake change and (4)the willingness to undertake change. We test the influence of place attachment and occupational identity on transformational capacity using the Australian peanut industry, which is presently assessing significant structural change in response to predicted climatic changes. Survey data from 88% of peanut farmers in Queensland show a strong negative correlation between transformational capacity and both place attachment and occupational attachment, suggesting that whilst these factors may be important positive influences on the capacity to adapt to incremental change, they act as barriers to transformational change
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