12,859 research outputs found
Flexibility in basal metabolic rate and evaporative water loss among hoopoe larks exposed to different environmental temperatures
The 'energy demand' hypothesis for short-term adjustments in basal metabolic rate (BMR) posits that birds adjust the size of their internal organs relative to food intake, a correlate of energy demand, We tested this hypothesis on hoopoe larks (Alaemon alaudipes), inhabitants of the Arabian desert, by acclimating birds for 3 weeks at 15 degreesC and at 36 degreesC, then measuring their BMR and total evaporative water loss (TEWL), Thereafter, we determined the dry masses of their brain, heart, liver, kidney, stomach, intestine and muscles of the pectoral region. Although mean body mass did not differ initially between the two groups, after 3 weeks, birds in the 15 degreesC group had gained mass (44.1+/-6.5g), whereas larks in the 36 degreesC group had maintained a constant mass (36.6+/-3.6g; means +/- S.D., N=6). Birds in the 15 degreesC group had a mean BMR of 46.8+/-6.9kJday(-1), whereas birds in the 36 degreesC group had a BMR of 32.9+/-6.3kJday(-1), values that were significantly different when we controlled for differences in body mass. When measured at 35 degreesC, larks in the cold-exposure group had a TEWL of 3.55+/-0.60gH(2)Oday(-1), whereas TEWL for birds in the 36 degreesC group averaged 2.23+/-0.28gH(2)Oday(-1), a difference of 59,2%, Mass-independent TEWL differed significantly between groups, Larks in the 15 degreesC group had a significantly larger liver, kidney and intestine than larks in the 36 degreesC group. The total increase in organ mass contributed 14.3 % towards the total mass increment in the cold exposure group, Increased food intake among larks in the cold group apparently resulted in enlargement of some of the internal organs, and the increase in mass of these organs required a higher rate of oxygen uptake to support them. As oxygen demands increased, larks apparently lost more evaporative water, but the relationship between increases in BMR and TEWL remains unresolved
Reconnaissance survey of a glaucous eucalypt near Louisa Bay, southwestern Tasmania
Stands of a glaucous eucalypt in the vicinity of Louisa Bay, southwestern Tasmania, which has affinities to Eucalyptus tenuiramis (Series Piperitae), were surveyed in order to determine their taxonomic status and record aspects of their population ecology. Two main populations were observed in scattered stands among predominantly moorland vegetation at the Red Point Hills and Louisa Plains. One stand from each population was accessed for detailed study. Contiguous plots located along transects across the copses were used to record changes in population status, floristics and site conditions. Individuals of the glaucous eucalypt were small in stature and frequently malleeform near the moorland boundary, but were taller (10-12 m) and straight with single, slender main stems toward the centre of the copse.
The Red Point Hills stand comprised a larger number of smaller individuals than the Louisa Plains stand and had been subject to at least three fires in the last 65 years, whereas only one fire had occurred on the Louisa Plains in the same period. These observations have implications for fire management: an appropriate regime, which encourages regeneration around the stand margins rather than increasing the edge-effects, needs to be devised. Given the geographic discontinuity with Eucalyptus tenuiramis, the southwestern copses may represent a relict dry sclerophyll community that was once contiguous with eastern Tasmania during the height of the last glaciation
Regeneration characteristics of a swamp forest in northwestern Tasmania
The botanical composition and regeneration characteristics are described for a Melaleuca ricifoliaLeptospermum
lanigerum forest from northwestern Tasmania. The size classes of the two dominant species are highly correlated with tree age. Size class analysis shows that the dominants are regenerating continuously. The relationship of this forest type to rainforest and wet sclerophyll forest are discussed
Optimizing fire station locations for the Istanbul metropolitan municipality
Copyright @ 2013 INFORMSThe Istanbul Metropolitan Municipality (IMM) seeks to determine locations for additional fire stations to build in Istanbul; its objective is to make residences and historic sites reachable by emergency vehicles within five minutes of a fire station’s receipt of a service request. In this paper, we discuss our development of a mathematical model to aid IMM in determining these locations by using data retrieved from its fire incident records. We use a geographic information system to implement the model on Istanbul’s road network, and solve two location models—set-covering and maximal-covering—as what-if scenarios. We discuss 10 scenarios, including the situation that existed when we initiated the project and the scenario that IMM implemented. The scenario implemented increases the city’s fire station coverage from 58.6 percent to 85.9 percent, based on a five-minute response time, with an implementation plan that spans three years
Magnetic Resonance Imaging Parameters at 1 Year Correlate With Clinical Outcomes Up to 17 Years After Autologous Chondrocyte Implantation
Background: The ability to predict the long-term success of surgical treatment in orthopaedics is invaluable, particularly in clinical trials. The quality of repair tissue formed 1 year after autologous chondrocyte implantation (ACI) in the knee was analyzed and compared with clinical outcomes over time. Hypothesis: Better quality repair tissue and a better appearance on magnetic resonance imaging (MRI) 1 year after ACI lead to improved longer-term clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Repair tissue quality was assessed using either MRI (11.5 ± 1.4 [n = 91] or 39.2 ± 18.5 [n = 76] months after ACI) or histology (16.3 ± 11.0 months [n = 102] after ACI). MRI scans were scored using the whole-organ magnetic resonance imaging score (WORMS) and the magnetic resonance observation of cartilage repair tissue (MOCART) score, with additional assessments of subchondral bone marrow and cysts. Histology of repair tissue was performed using the Oswestry cartilage score (OsScore) and the International Cartilage Repair Society (ICRS) II score. Clinical outcomes were assessed using the modified Lysholm score preoperatively, at the time of MRI or biopsy, and at a mean 8.4 ± 3.7 years (maximum, 17.8 years) after ACI. Results: At 12 months, the total MOCART score and some of its individual parameters correlated significantly with clinical outcomes. The degree of defect fill, overall signal intensity, and surface of repair tissue at 12 months also significantly correlated with longer-term outcomes. The presence of cysts or effusion (WORMS) significantly correlated with clinical outcomes at 12 months, while the presence of synovial cysts/bursae preoperatively or the absence of loose bodies at 12 months correlated significantly with long-term clinical outcomes. Thirty percent of repair tissue biopsies contained hyaline cartilage, 65% contained fibrocartilage, and 5% contained fibrous tissue. Despite no correlation between the histological scores and clinical outcomes at the time of biopsy, a lack of hyaline cartilage or poor basal integration was associated with increased pain; adhesions visible on MRI also correlated with significantly better histological scores. Conclusion: These results demonstrate that MRI at 12 months can predict longer-term clinical outcomes after ACI. Further investigation regarding the presence of cysts, effusion, and adhesions and their relationship with histological and clinical outcomes may yield new insights into the mechanisms of cartilage repair and potential sources of pain
Amygdala responses to fearful and happy facial expressions under conditions of binocular suppression
The human amygdala plays a crucial role in processing affective information conveyed by sensory stimuli. Facial expressions of fear and anger, which both signal potential threat to an observer, result in significant increases in amygdala activity, even when the faces are unattended or presented briefly and masked. It has been suggested that afferent signals from the retina travel to the amygdala via separate cortical and subcortical pathways, with the subcortical pathway underlying unconscious processing. Here we exploited the phenomenon of binocular rivalry to induce complete suppression of affective face stimuli presented to one eye. Twelve participants viewed brief, rivalrous visual displays in which a fearful, happy, or neutral face was presented to one eye while a house was presented simultaneously to the other. We used functional magnetic resonance imaging to study activation in the amygdala and extrastriate visual areas for consciously perceived versus suppressed face and house stimuli. Activation within the fusiform and parahippocampal gyri increased significantly for perceived versus suppressed faces and houses, respectively. Amygdala activation increased bilaterally in response to fearful versus neutral faces, regardless of whether the face was perceived consciously or suppressed because of binocular rivalry. Amygdala activity also increased significantly for happy versus neutral faces, but only when the face was suppressed. This activation pattern suggests that the amygdala has a limited capacity to differentiate between specific facial expressions when it must rely on information received via a subcortical route. We suggest that this limited capacity reflects a tradeoff between specificity and speed of processing
Vegetation and the importance of insecticide-treated target siting for control of Glossina fuscipes fuscipes
Control of tsetse flies using insecticide-treated targets is often hampered by vegetation re-growth and encroachment which obscures a target and renders it less effective. Potentially this is of particular concern for the newly developed small targets (0.25 high × 0.5 m wide) which show promise for cost-efficient control of Palpalis group tsetse flies. Consequently the performance of a small target was investigated for Glossina fuscipes fuscipes in Kenya, when the target was obscured following the placement of vegetation to simulate various degrees of natural bush encroachment. Catches decreased significantly only when the target was obscured by more than 80%. Even if a small target is underneath a very low overhanging bush (0.5 m above ground), the numbers of G. f. fuscipes decreased by only about 30% compared to a target in the open. We show that the efficiency of the small targets, even in small (1 m diameter) clearings, is largely uncompromised by vegetation re-growth because G. f. fuscipes readily enter between and under vegetation. The essential characteristic is that there should be some openings between vegetation.
This implies that for this important vector of HAT, and possibly other Palpalis group flies, a smaller initial clearance zone around targets can be made and longer interval between site maintenance visits is possible both of which will result in cost savings for large scale operations. We also investigated and discuss other site features e.g. large solid objects and position in relation to the water's edge in terms of the efficacy of the small targets
Exploring differential item functioning in the SF-36 by demographic, clinical, psychological and social factors in an osteoarthritis population
The SF-36 is a very commonly used generic measure of health outcome in osteoarthritis (OA). An important, but frequently overlooked, aspect of validating health outcome measures is to establish if items work in the same way across subgroup of a population. That is, if respondents have the same 'true' level of outcome, does the item give the same score in different subgroups or is it biased towards one subgroup or another. Differential item functioning (DIF) can identify items that may be biased for one group or another and has been applied to measuring patient reported outcomes. Items may show DIF for different conditions and between cultures, however the SF-36 has not been specifically examined in an osteoarthritis population nor in a UK population. Hence, the aim of the study was to apply the DIF method to the SF-36 for a UK OA population. The sample comprised a community sample of 763 people with OA who participated in the Somerset and Avon Survey of Health. The SF-36 was explored for DIF with respect to demographic, social, clinical and psychological factors. Well developed ordinal regression models were used to identify DIF items. Results: DIF items were found by age (6 items), employment status (6 items), social class (2 items), mood (2 items), hip v knee (2 items), social deprivation (1 item) and body mass index (1 item). Although the impact of the DIF items rarely had a significant effect on the conclusions of group comparisons, in most cases there was a significant change in effect size. Overall, the SF-36 performed well with only a small number of DIF items identified, a reassuring finding in view of the frequent use of the SF-36 in OA. Nevertheless, where DIF items were identified it would be advisable to analyse data taking account of DIF items, especially when age effects are the focus of interest
Is the Shroud of Turin in Relation to the Old Jerusalem Historical Earthquake?
Phillips and Hedges suggested, in the scientific magazine Nature (1989), that
neutron radiation could be liable of a wrong radiocarbon dating, while proton
radiation could be responsible of the Shroud body image formation. On the other
hand, no plausible physical reason has been proposed so far to explain the
radiation source origin, and its effects on the linen fibres. However, some
recent studies, carried out by the first author and his Team at the Laboratory
of Fracture Mechanics of the Politecnico di Torino, found that it is possible
to generate neutron emissions from very brittle rock specimens in compression
through piezonuclear fission reactions. Analogously, neutron flux increments,
in correspondence to seismic activity, should be a result of the same
reactions. A group of Russian scientists measured a neutron flux exceeding the
background level by three orders of magnitude in correspondence to rather
appreciable earthquakes (4th degree in Richter Scale). The authors consider the
possibility that neutron emissions by earthquakes could have induced the image
formation on Shroud linen fibres, trough thermal neutron capture by Nitrogen
nuclei, and provided a wrong radiocarbon dating due to an increment in
C(14,6)content. Let us consider that, although the calculated integral flux of
10^13 neutrons per square centimetre is 10 times greater than the cancer
therapy dose, nevertheless it is100 times smaller than the lethal dose.Comment: 13 pages, 1 figur
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