24,181 research outputs found
Double U-slots patch antenna for tri-band wireless systems
No full textFile shown is the pre-print version of the published paper, with the title "Connected u-slots pathch antenna for WiMAX applications"ABSTRACT: A compact microstrip patch antenna with two U-slots shape is presented.
Detailed simulation and experimental investigation are conducted to understand the behavior
of the two U-slots. The proposed antenna generates three resonant frequencies at 2.7, 3.3, and
5.3 GHz. It can, therefore, be used in Worldwide Interoperability for Microwave Access compliant
communication equipment. The proposed antenna has two U-slot shaped and two
bridge elements to connect both shapes together to adapt the structure to the desired interest
operating frequency. A comprehensive parametric study has been applied to understand the
effect of each U-slot on the antenna’s performance. Moreover, the current distribution for the
three bands is investigated to give further understanding of the antenna behavior. The proposed
antenna is verified experimentally and the simulated and measured results are in good
agreement
Rapid Establishment of a Regular Distribution of Adult Tropical Drosophila Parasitoids in a Multi-Patch Environment by Patch Defence Behaviour.
No full textFemales of the larval parasitoid of Drosophila, Asobara citri, from sub-Saharan Africa, defend patches with hosts by fighting and chasing conspecific females upon encounter. Females of the closely related, palearctic species Asobara tabida do not defend patches and often search simultaneously in the same patch. The effect of patch defence by A. citri females on their distribution in a multi-patch environment was investigated, and their distributions were compared with those of A. tabida. For both species 20 females were released from two release-points in replicate experiments. Females of A. citri quickly reached a regular distribution across 16 patches, with a small variance/mean ratio per patch. Conversely, A. tabida females initially showed a clumped distribution, and after gradual dispersion, a more Poisson-like distribution across patches resulted (variance/mean ratio was closer to 1 and higher than for A. citri). The dispersion of A. tabida was most probably an effect of exploitation: these parasitoids increasingly made shorter visits to already exploited patches. We briefly discuss hypotheses on the adaptive significance of patch defence behaviour or its absence in the light of differences in the natural history of both parasitoid species, notably the spatial distribution of their hosts
On a slender dry patch in a liquid film draining under gravity down an inclined plane
No full textIn this paper two similarity solutions describing a steady, slender, symmetric dry patch in an infinitely wide liquid film draining under gravity down an inclined plane are obtained. The first solution, which predicts that the dry patch has a parabolic shape and that the transverse profile of the free surface always has a monotonically increasing shape, is appropriate for weak surface-tension effects and far from the apex of the dry patch. The second solution, which predicts that the dry patch has a quartic shape and that the transverse profile of the free surface has a capillary ridge near the contact line and decays in an oscillatory manner far from it, is appropriate for strong surface-tension effects (in particular, when the plane is nearly vertical) and near (but not too close) to the apex of the dry patch. With the average volume flux per unit width (or equivalently with the uniform height of the layer far from the dry patch) prescribed, both solutions contain a free parameter. For each value of this parameter there is a unique solution in the first case and either no solution or a one-parameter family of solutions in the second case. The solutions capture some of the qualitative features observed in experiments
Triple band double U-slots patch antenna for WiMAX mobile applications
No full textA small triple-band 2.7 GHz, 3.2 GHz and 5.3 GHz compact microstrip patch antenna with two U-shaped slots and a small ground plane is presented. It has been developed to be used in future WiMAX technology. The required bandwidths are fulfilled the WiMAX technology 4.8 %, 3 % and 2.5 % respectively. The return loss for the triple band are -18.5 dB, -14.5 dB and -19 respectively
Safety of opioid patch initiation in Australian residential aged care
No full textExplores opioid use by aged care facility residents before and after initiation of transdermal opioid patches.
Abstract
Objective: To explore opioid use by aged care facility residents before and after initiation of transdermal opioid patches.
Design: A cross-sectional cohort study, analysing pharmacy data on individual patient supply between 1 July 2008 and 30 September 2013.
Setting: Sixty residential aged care facilities in New South Wales.
Participants: Residents receiving an initial opioid patch during the study period
Main outcome measure: The proportion of residents who were opioid-naive in the 4 weeks prior to patch initiation was determined. In addition, the patch strength at initiation and the daily dose of transdermal patches and of additional opioids 1 month after initiation were determined.
Results: An opioid patch was initiated in 596 of 5297 residents (11.3%: 2.6% fentanyl, 8.7% buprenorphine) in the 60 residential aged care facilities. The mean age at initiation was 87 years, and 74% of the recipients were women. The proportion of recipients who were opioid-naive before patch initiation was 34% for fentanyl and 49% for buprenorphine. Most were initiated at the lowest available patch strength, and the dose was up-titrated after initiation. Around 15% of fentanyl users and 10% of buprenorphine users needed additional regular opioids after patch initiation.
Conclusions: The results suggest some inappropriate initiation of opioid patches in Australian residential aged care facilities. Contrary to best practice, a third of residents initiated on fentanyl patches were opioid-naive in the 4 weeks before initiation.
 
Depigmented wing patch size is a condition-dependent indicator of viability in male collared flycatchers
No full textHonesty of sexual advertisement is thought to be the result of signalling costs. Because production costs of depigmented plumage patches are probably very low, their role as honest signals of individual quality has been questioned. Costs of bearing these traits, however, should also be taken into account. Studies on proximate determination and possible information content of white badges are very rare. We investigated repeatability, sensu lato heritability, and condition- and age-dependence of white wing patch size, a male display trait in a population of collared flycatchers (Ficedula albicollis), based on 4 years of data. By comparing relationships between age and wing patch size (1) within individuals among years versus (2) among individuals within years, we could address the viability indicator value of the trait. Wing patch size approximately doubled at the transition from subadult to adult plumage, and its change was significantly related to body condition the previous season. Repeatability and heritability values suggest that the trait is informative already in subadult plumage, and that genetic and early environmental effects are important in its determination, the latter only during the first year of life. Thus, wing patch size can act as a condition-dependent signal of genetic quality. Indeed, discrepancy between results from the horizontal and vertical age-dependence approaches shows that the trait was positively related to expected lifespan. After examining several alternative explanations, we conclude that wing patch size indicates genetically based viability. This is the first study to demonstrate a good genes viability benefit conferred by a depigmented plumage patch
Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers
No full textThis is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the literature as formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine formaldehyde in products and frequency of exposure to formaldehyde and releasers. The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test reactions is often challenging. What concentration of formaldehyde is safe for sensitive patients remains unknown. Levels of 200-300 p.p.m. free formaldehyde in cosmetic products have been shown to induce dermatitis from short-term use on normal skin
How can cells in the anterior medial face patch be viewpoint invariant?
No full textIn a recent paper, Freiwald and Tsao (2010) found evidence that the responses of cells in the macaque anterior medial (AM) face patch are invariant to significant changes in viewpoint. The monkey subjects had no prior experience with the individuals depicted in the stimuli and were never given an opportunity to view the same individual from different viewpoints sequentially. These results cannot be explained by a mechanism based on temporal association of experienced views. Employing a biologically plausible model of object recognition (software available at cbcl.mit.edu), we show two mechanisms which could account for these results. First, we show that hair style and skin color provide sufficient information to enable viewpoint recognition without resorting to any mechanism that associates images across views. It is likely that a large part of the effect described in patch AM is attributable to these cues. Separately, we show that it is possible to further improve view-invariance using class-specific features (see Vetter 1997). Faces, as a class, transform under 3D rotation in similar enough ways that it is possible to use previously viewed example faces to learn a general model of how all faces rotate. Novel faces can be encoded relative to these previously encountered “template” faces and thus recognized with some degree of invariance to 3D rotation. Since each object class transforms differently under 3D rotation, it follows that invariant recognition from a single view requires a recognition architecture with a detection step determining the class of an object (e.g. face or non-face) prior to a subsequent identification stage utilizing the appropriate class-specific features
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
Dispersal mode mediates the effect of patch size and patch connectivity on metacommunity diversity
No full textMetacommunity theory predicts that increasing patch size and patch connectivity can alter local species diversity by affecting either colonization rates, extinction rates or both. Although species' dispersal abilities or 'dispersal mode' (e.g. gravity-, wind- or animal-dispersed seeds) can mediate the effects of patch size and connectivity on diversity, these important factors are frequently overlooked in empirical metacommunity work. We use a natural metacommunity of aspen stands within a grassland matrix to determine whether dispersal mode alters the influence of stand size and connectivity on understorey plant diversity. We sampled the same area in each patch, controlled for the presence of matrix species in aspen stands, and tested for the effects of size, connectivity and dispersal mode on metacommunity richness. Because dispersal groups responded differently to patch size and connectivity, we created a null model and assessed ungulate activity to explore whether competitive dynamics or herbivory were driving diversity patterns. Animal-dispersed species and species with no dispersal aid had higher diversity per unit area in larger stands, likely because large stands can both support larger populations that are less prone to extinction and may also attract seed-dispersing animals such as birds and small mammals that are sensitive to edge effects. Consistent with other empirical work, we found a positive relationship between diversity and connectivity for wind-dispersed species. However, we detected a negative effect of stand connectivity on the diversity of species with no dispersal aid, possibly due to the presence of other highly competitive species groups dominating well-connected patches, as our null model results suggest. We found no evidence for higher ungulate activity in highly connected patches, suggesting that herbivory may not be driving the decline in diversity of plants with no dispersal aid. Synthesis. Overall, we see a positive effect of stand area on diversity for most groups despite sampling equal area in all stands, which is a prediction of metacommunity theory that is normally overlooked. Our results demonstrate the importance of considering variation in the dispersal modes of focal species for explaining the diversity patterns of natural metacommunities. We see a positive effect of stand area on diversity for most dispersal modes despite sampling equal area in all stands, which is a prediction of metacommunity theory that is normally overlooked. Our results demonstrate the importance of considering variation in the dispersal modes of focal species for explaining the diversity patterns of natural metacommunities
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