Mimicry is one of the best-studied examples of adaptation, and recent studies have provided new insights into the role of mimicry in speciation and diversification. Classical Müllerian mimicry theory ...predicts convergence in warning signal among protected species, yet tropical butterflies are exuberantly diverse in warning colour patterns, even within communities. We tested the hypothesis that microhabitat partitioning in aposematic butterflies and insectivorous birds can lead to selection for different colour patterns in different microhabitats and thus help maintain mimicry diversity. We measured distribution across flight height and topography for 64 species of clearwing butterflies (Ithomiini) and their co-mimics, and 127 species of insectivorous birds, in an Amazon rainforest community. For the majority of bird species, estimated encounter rates were non-random for the two most abundant mimicry rings. Furthermore, most butterfly species in these two mimicry rings displayed the warning colour pattern predicted to be optimal for anti-predator defence in their preferred microhabitats. These conclusions were supported by a field trial using butterfly specimens, which showed significantly different predation rates on colour patterns in two microhabitats. We therefore provide the first direct evidence to support the hypothesis that different mimicry patterns can represent stable, community-level adaptations to differing biotic environments.
Most previous studies evaluating the use of methylphenidate following traumatic brain injury (TBI) have been conducted many years post-injury. This study evaluated the efficacy of methylphenidate in ...facilitating cognitive function in the inpatient rehabilitation phase.
40 participants with moderate-severe TBI (mean 68 days post-injury) were recruited into a randomised, crossover, double blind, placebo controlled trial. Methylphenidate was administered at a dose of 0.3 mg/kg twice daily and lactose in identical capsules served as placebo. Methylphenidate and placebo administration was randomised in a crossover design across six sessions over a 2 week period. Primary efficacy outcomes were neuropsychological tests of attention.
No participants were withdrawn because of side effects or adverse events. Methylphenidate significantly increased speed of information processing on the Symbol Digit Modalities Test (95% CI 0.30 to 2.95, Cohen's d = 0.39, p = 0.02), Ruff 2 and 7 Test-Automatic Condition (95% CI 1.38 to 6.12, Cohen's d = 0.51, p = 0.003), Simple Selective Attention Task (95% CI -58.35 to -17.43, Cohen's d = 0.59, p = 0.001) and Dissimilar Compatible (95% CI -70.13 to -15.38, Cohen's d = 0.51, p = 0.003) and Similar Compatible (95% CI -74.82 to -19.06, Cohen's d = 0.55, p = 0.002) conditions of the Four Choice Reaction Time Task. Those with more severe injuries and slower baseline information processing speed demonstrated a greater drug response.
Methylphenidate enhances information processing speed in the inpatient rehabilitation phase following TBI. This trial is registered with the Australian New Zealand Clinical Trials Registry (12607000503426).
Introduction: Participation rates and quality-of-life (QoL) have been a major focus of rehabilitation programmes and outcome studies following traumatic brain injury (TBI). The extent to which ...mobility limitations impact on participation rates and QoL has not been thoroughly explored. The main aim of this study was to investigate the relationship between mobility limitations, participation rates and QoL following TBI.
Methods: Thirty-nine people who had sustained an extremely severe TBI were recruited from a major rehabilitation facility. Mobility was quantified using the high-level mobility assessment tool (HiMAT). The Brain Injury Community Rehabilitation Outcome (BICRO-39) and Community Integration Questionnaire (CIQ) were used to measure participation rates and the shorter version of the World Health Organization Quality of Life (WHOQoL-BREF) and Assessment of Quality-of-Life (AQoL-2) were used to measure QoL.
Results: Mobility was most strongly correlated with the total BICRO-39 score (r = −0.60, p < 0.001) and the mobility domain (r = −0.59, p < 0.001) of the BICRO-39. Although mobility had a significant relationship with health-related QoL, AQoL-2 (r = 0.60, p < 0.001), it was most strongly related to the AQoL-2 independent living domain (r = 0.79, p < 0.001).
Conclusion: Greater capacity to mobilize was associated with higher participation rates and better QoL.
Spatial cross-validation and average-error statistics are examined with respect to their abilities to evaluate alternate spatial interpolation methods. A simple cross-validation methodology is ...described, and the relative abilities of three, dimensioned error statistics-the root-mean-square error (RMSE), the mean absolute error (MAE), and the mean bias error (MBE)-to describe average interpolator performance are examined. To illustrate our points, climatologically averaged weather-station temperatures were obtained from the Global Historical Climatology Network (GHCN), Version 2, and then alternately interpolated spatially (gridded) using two spatial-interpolation procedures. Substantial differences in the performance of our two spatial interpolators are evident in maps of the cross-validation error fields, in the average-error statistics, as well as in estimated land-surface-average air temperatures that differ by more than 2°C. The RMSE and its square, the mean-square error (MSE), are of particular interest, because they are the most widely reported average-error measures, and they tend to be misleading. It (RMSE) is an inappropriate measure of average error because it is a function of three characteristics of a set of errors, rather than of one (the average error). Our findings indicate that MAE and MBE are natural measures of average error and that (unlike RMSE) they are unambiguous.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The relative abilities of 2, dimensioned statistics—the root-mean-square error (RMSE) and the mean absolute error (MAE)—to describe average model-performance error are examined. The RMSE is of ...special interest because it is widely reported in the climatic and environmental literature; nevertheless, it is an inappropriate and misinterpreted measure of average error. RMSE is inappropriate because it is a function of 3 characteristics of a set of errors, rather than of one (the average error). RMSE varies with the variability within the distribution of error magnitudes and with the square root of the number of errors (n
1/2), as well as with the average-error magnitude (MAE). Our findings indicate that MAE is a more natural measure of average error, and (unlike RMSE) is unambiguous. Dimensioned evaluations and inter-comparisons of average model-performance error, therefore, should be based on MAE.
To more fully understand the role of precipitation in observed increases in freshwater discharge to the Arctic Ocean, data from a new archive of bias‐adjusted precipitation records for the former ...USSR (TD9813), along with the CRU and Willmott‐Matsuura data sets, were examined for the period 1936–1999. Across the six largest Eurasian river basins, snowfall derived from TD9813 exhibits a strongly significant increase until the late 1950s and a moderately significant decrease thereafter. A strongly significant decline in derived rainfall is also noted. Spatially, snowfall increases are found primarily across north‐central Eurasia, an area where the rainfall decreases are most prominent. Although no significant change is determined in Eurasian‐basin snowfall over the entire 64 year period, we note that interpolation from early, uneven station networks causes an overestimation of spatial precipitation, and that the local snowfall trends determined from gridded TD9813 data are likely underestimated. Yet, numerous uncertainties in historical Arctic climate data and the sparse, irregular nature of Arctic station networks preclude a confident assessment of precipitation‐discharge linkages during the period of reported discharge trends.
Background: The impact of mild head injury is variable and determinants of outcome remain poorly understood. Results of previous intervention studies have been mixed. Objectives: To evaluate the ...impact on outcome of the provision of information, measured in terms of reported symptoms, cognitive performance, and psychological adjustment three months postinjury. Methods: 202 adults with mild head injury were studied: 79 were assigned to an intervention group and were assessed one week and three months after injury; 123 were assigned to a non-intervention control group and were seen at three months only. Participants completed measures of preinjury psychological adjustment, concurrent life stresses, post-concussion symptoms, and tests of attention, speed of information processing, and memory. Subjects seen at one week were given an information booklet outlining the symptoms associated with mild head injury and suggested coping strategies. Those seen only at three months after injury did not receive this booklet. Results: Patients in the intervention group who were seen at one week and given the information booklet reported fewer symptoms overall and were significantly less stressed at three months after the injury. Conclusions: The provision of an information booklet reduces anxiety and reporting of ongoing problems.
Oxygen consumption after surgery is increased in response to the tissue trauma sustained intra-operatively and the subsequent systemic inflammatory response that ensues. The cardio-respiratory system ...must match the tissue oxygen and metabolic requirements; otherwise, peri-operative complications may occur. Existing data is several decades old. The primary objective of this feasibility study was to determine the ease of recruiting participants and collecting relevant data to assess the extent and duration of increased oxygen consumption and post-operative complications after major abdominal surgery in contemporaneous times.
One hundred patients scheduled for elective colorectal surgery requiring a bowel resection were screened to test specific feasibility criteria relating to ease of recruitment, duration of post-operative stay, ease of data collection, and drop-out rates. A calibrated metabolic cart was used to obtain unblinded pre-operative resting oxygen consumption recordings. The metabolic cart was then used to obtain post-operative oxygen consumption readings on days 1 to 5 as long as the participant remained as an inpatient. At the time of the oxygen consumption reading, a Post-Operative Morbidity Survey score (POMS) was calculated. Feasibility outcomes chosen a priori were that at least one participant would be recruited every 2 weeks from the pre-admission colorectal clinic, at least 10% of potential subjects screened would be enrolled, at least 80% of recruited participants would have a minimum post-operative stay of 2 nights, a minimum of 3 consecutive days of oxygen consumption data would be collected for each subject, at least 8 of 9 POMS score domains would be completed per participant per day and the drop-out rate would be no greater than 10%. We deemed that screening 100 patients would be sufficient to test our feasibility outcomes.
Twelve participants completed the protocol. All pre-specified feasibility criteria were met. No increase in post-operative oxygen consumption was observed in this feasibility cohort.
The protocol and experiences gained from this feasibility study could be used to plan a larger study to better define changes in post-operative oxygen consumption after major abdominal surgery utilizing current surgical techniques.
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