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Comparing Data (comparing + data)
Selected AbstractsIn-Hive Behavior of Pollen Foragers (Apis mellifera) in Honey Bee Colonies Under Conditions of High and Low Pollen NeedETHOLOGY, Issue 3 2002Anja Weidenmüller Pollen collection in honey bees is regulated around a homeostatic set-point. How the control of pollen collection is achieved is still unclear. Different feedback mechanisms have been proposed but little is known about the experience of pollen foragers in the hive. A detailed documentation of the behavior of pollen foragers in the hive under different pollen need conditions is presented here. Taking a broad observational approach, we analyze the behavior of individual pollen foragers in the hive between collecting trips and quantify the different variables constituting the in-hive stay. Comparing data from two colonies and 143 individuals during experimentally induced times of low vs. times of high pollen need, we show that individual foragers modulate their in-hive working tempo according to the actual pollen need of the colony: pollen foragers slowed down and stayed in the hive longer when pollen need was low and spent less time in the hive between foraging trips when pollen need by their colony was high. Furthermore, our data show a significant change in the trophallactic experience of pollen foragers with changing pollen need conditions of their colony. Pollen foragers had more short (< 3 s) trophallactic contacts when pollen need was high, resulting in an increase of total number of trophallactic contacts. Thus, our results support the hypothesis that trophallactic experience is one of the various information pathways used by pollen foragers to assess their colony's pollen need. [source] Discrepancies in Reported Levels of International Wildlife TradeCONSERVATION BIOLOGY, Issue 6 2005ARTHUR G. BLUNDELL aduanas; CITES; especies en peligro; programa de aranceles armonizados Abstract:,The international wildlife trade is a principal cause of biodiversity loss, involving hundreds of millions of plants and animals each year, yet wildlife trade records are notoriously unreliable. We assessed the precision of wildlife trade reports for the United States, the world's largest consumer of endangered wildlife, by comparing data from the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) with U.S. Customs data. For both U.S. imports and exports, CITES and Customs reported substantially different trade volumes for all taxa in all years. Discrepancies ranged from a CITES-reported volume 376% greater than that reported by Customs (live coral imports, 2000) to a Customs' report 5202% greater than CITES (conch exports, 2000). These widely divergent data suggest widespread inaccuracies that may distort the perceived risk of targeted wildlife exploitation, leading to misallocation of management resources and less effective conservation strategies. Conservation scientists and practitioners should reexamine assumptions regarding the significance of the international wildlife trade. Resumen:,El comercio internacional de vida silvestre es una causa principal de la pérdida de biodiversidad, ya que involucra a cientos de millones de plantas y animales cada año; no obstante eso, los registros del comercio son notoriamente poco confiables. Evaluamos la precisión de los registros de comercio de vida silvestre de Estados Unidos, el mayor consumidor de vida silvestre en peligro en el mundo, mediante la comparación de datos del Convenio Internacional para el Comercio de Especies de Flora y Fauna Silvestre en Peligro (CITES) con datos de la Aduana de E.U.A. Tanto para importaciones como exportaciones, CITES y Aduana reportaron volúmenes de comercio de todos los taxa sustancialmente diferentes en todos los años. Las discrepancias abarcaron desde un volumen reportado por CITES 376% más grande que el reportado por la Aduana (importaciones de coral vivo, 2000) hasta un reporte de la Aduana 5202% mayor que el de CITES (exportaciones de caracol, 2000). Estos datos ampliamente divergentes sugieren imprecisiones generalizadas que pueden distorsionar el riesgo percibido por la explotación de vida silvestre, lo que conducirá a la incorrecta asignación de recursos para la gestión y a estrategias de conservación menos efectivas. Los científicos y profesionales de la conservación deberían reexaminar sus suposiciones respecto al significado del comercio internacional de vida silvestre. [source] Sampling and analysis of microcystins: Implications for the development of standardized methodsENVIRONMENTAL TOXICOLOGY, Issue 2 2007Angeline R. Tillmanns Abstract Microcystins (MC), a group of cyanotoxins, have been found in lakes and rivers worldwide. One goal of MC research is to develop models which predict MC concentrations, but these efforts have been hampered by a lack of standardized methods necessary for comparing data across studies. Here, we investigate the effect of chemical analysis (HPLC-PDA and ELISA), sample collection (whole water, plankton tow and surface scum), and choice of normalizing parameter (volume, dry weight, and chlorophyll a) on reported MC concentrations. Samples were collected over three years from a temperate mesotrophic, shallow lake with episodic blooms of cyanobacteria. We found that microcystins were up to four times higher in lake samples when analyzed by ELISA relative to HPLC-PDA and that MC concentration measured by HPLC explained less than half of the variation in MC concentrations measured by ELISA. Also, samples collected by plankton tow gave consistently higher concentrations than whole water samples. An additional HPLC analysis of two chlorophyte cultures revealed the presence of compounds with a similar UV absorbance spectrum to MC-LR, suggesting that identifying MC based solely on UV absorbance is not valid. Our results document the discrepancy in MC concentrations that can arise by using different methods throughout all stages of sampling, analysis, and reporting of MC concentrations. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 132,143, 2007. [source] The Effect of Crossing-Network Trading on Dealer Market's Bid-Ask SpreadsEUROPEAN FINANCIAL MANAGEMENT, Issue 2 2006Carole Gresse G19 Abstract This article provides new insights into market competition between traditional exchanges and alternative trading systems in Europe. It investigates the relationship between the trading activity of a crossing network (CN) and the liquidity of a traditional dealer market (DM) by comparing data from the SEAQ quote-driven segment of the London Stock Exchange (LSE) and internal data from the POSIT crossing network. A cross-sectional analysis of bid-ask spreads shows that DM spreads are negatively related to CN executions. Risk-sharing benefits from CN trading dominate fragmentation and cream-skimming costs. Further, risk-sharing gains are found to be related to dealer trading in the CN. [source] The relationship between performance appraisal criterion specificity and statistical evidence of discriminationHUMAN RESOURCE MANAGEMENT, Issue 2 2003H. W. Hennessey Jr. Plaintiffs' expert witnesses in EEO cases involving performance appraisals often claim that adverse impact is a result of the type of rating format used. Their theory is that more specific rating criteria will lead to lessened adverse impact. We tested that theory by comparing data from a simple category-based rating system against data from a standards-based Work Planning and Review appraisal system with over 248,000 performance appraisals of state employees. Using logistic regression and statistical definitions of prima facie discrimination, we found no support for the hypothesis that adverse impact is materially affected by criterion specificity. © 2003 Wiley Periodicals, Inc. [source] Wind speed measurements and forest damage in Canton Zurich (Central Europe) from 1891 to winter 2007INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2010Tilo Usbeck Abstract The most severe damage to forests in central Europe occurs during winter storms that are caused by Northern Hemispheric mid-latitude cyclones. These winter storms have caused several catastrophic windthrows during the past four decades. Amounts of forest storm damage are believed to be a function of both the size of the forest and the storm intensity. To test this hypothesis, the Zurich region (city and canton) was chosen because long-term climate observation data is available for the region. The relationships between forest attributes, wind speed and forest damage were explored by comparing data on forests and wind speed from 107 winters with forest damage. Storm damage was defined as the proportion of damaged forests with respect to the growing stock. The variables: daily wind run (91 years), daily maximum hourly average wind speed (107 years) and peak gust wind speed (74 years) were homogenized with respect to high wind speed and related to levels of forest damage. High maximum wind speed at the end of the 19th century and at the beginning of the 20th century was followed by low maximum wind speed in the 1940s, 1960s and 1970s. Since then, maximum values have increased. Gusts (extremes of the maximum wind speed) increased from the beginning of the recordings in 1933 and peaked in the early 1990s. Forest damage due to winter storms is best correlated with peak wind speed. Gusts exceeding 40 m/s and resulting in catastrophic windthrow have increased in recent winters. Copyright © 2009 Royal Meteorological Society [source] Molt and growth of an estuarine crab, Chasmagnathus granulatus (Brachyura: Varunidae), in Mar Chiquita coastal lagoon, ArgentinaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2004T. A. Luppi Summary Juvenile and adult growth of Chasmagnathus granulatus was studied in the laboratory in terms of molt increment in size (MI) and the intermolt period (IP), comparing data obtained from short-term (STE) and long-term (LTE) laboratory experiments. Crabs in a pre-molt condition were collected for STE, including the entire size range of the species. Larger crabs remained in the laboratory no more than 14 days; the average time to molt was 5.8 ± 3.1 days. We registered the molt of 94 females, 64 males and 34 undifferentiated juveniles and calculated their MI. Moreover, 24 males and four females were reared in the laboratory over 3 years (LTE). Hiatt diagrams did not show sex-specific differences between juveniles of both sexes, but revealed differences between juveniles and adults in each sex as well as between adults of both sexes. The MI decreased gradually with size; this pattern was described with a quadratic model. The IP increased exponentially with size. The presence of regenerating limbs diminished the MI. The abdomen of females reached its final shape and maximum relative width at functional maturity. Growth curves for both sexes were calculated using the von Bertalanffy model, but this model yielded an underestimation of the actual maximum size of this crab. [source] The orientation system and migration pattern of long-distance migrants: conflict between model predictions and observed patternsJOURNAL OF AVIAN BIOLOGY, Issue 2 2001Kasper Thorup The requirements of the orientation system of naïve long-distance night migrants were analysed by comparing data on Barred Warbler Sylvia nisoria, Marsh Warbler Acrocephalus palustris and Spotted Flycatcher Muscicapa striata with data from a computer model of a clock-and-compass system. These species show, respectively, a rather restricted winter distribution in East Africa, migration through a very narrow corridor in East Africa, and rather widely distributed recoveries in the Mediterranean with more concentrated recoveries south of the Sahara. For all three species, to obtain the observed concentrations either a very high directional migratory concentration was needed in computer simulations to bring the birds successfully to their wintering areas or misorientating individuals would be subjected to a very high mortality. Neither the very high directional concentration nor the high mortality amongst misorientating individuals fit the empirical data sets. On the basis of the present study, the observed patterns seem difficult to explain by a simple clock-and-compass system only, and to account for the exceptionally precise migratory routes shown in this study it is proposed that first-time migrants might be able to use landscape topography on a regional scale in combination with corrections of directional mistakes/wind displacements. [source] The development of PET radioligands for imaging the translocator protein (18,kDa): What have we learned?JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2010Christopher Luus Abstract The translocator protein (TSPO; 18,kDa), formerly known as the peripheral benzodiazepine receptor (PBR), is minimally expressed in the healthy brain. On the other hand, increased levels of TSPO have been noted in brain disorders for which an immune response is elicited. This increase in TSPO expression has been reported to coincide with the process of microglial activation making the measurement of TSPO density a useful indicator of active brain disease. To this end several new classes of TSPO positron emission tomography radioligands have been developed and evaluated. However, the incomplete pharmacological characterization of the TSPO and its ligands as well as differences in pathophysiology, pharmacology and molecular nature across species and tissue types means that caution must be exercised when comparing data obtained with various TSPO radioligands. A re-evaluation of our interpretation of imaging data, which better correlates with our current understanding of TSPO pharmacology in disease, requires consideration. Copyright © 2010 John Wiley & Sons, Ltd. [source] Definition of major bleeding in clinical investigations of antihemostatic medicinal products in non-surgical patientsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2005S. SCHULMAN Summary., A variety of definitions of major bleeding have been used in published clinical studies, and this diversity adds to the difficulty in comparing data between trials and in performing meta-analyses. In the first step towards unified definitions of bleeding complications, the definition of major bleeding in non-surgical patients was discussed at the Control of Anticoagulation Subcommittee of the International Society on Thrombosis and Haemostasis. Arising from that discussion, a definition was developed that should be applicable to studies with all agents that interfere with hemostasis, including anticoagulants, platelet function inhibitors and fibrinolytic drugs. The definition and the text that follows have been reviewed and approved by the cochairs of the subcommittee and the revised version is published here. The intention is to also seek approval of this definition from the regulatory authorities. [source] Technical note: A new method for measuring long bone curvature using 3D landmarks and semi-landmarksAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Isabelle De Groote Abstract Here we describe and evaluate a new method for quantifying long bone curvature using geometric morphometric and semi-landmark analysis of the human femur. The technique is compared with traditional ways of measuring subtense and point of maximum curvature using either coordinate calipers or projection onto graph paper. Of the traditional methods the graph paper method is more reliable than using coordinate calipers. Measurement error is consistently lower for measuring point of maximum curvature than for measuring subtense. The results warrant caution when comparing data collected by the different traditional methods. Landmark data collection proves reliable and has a low measurement error. However, measurement error increases with the number of semi-landmarks included in the analysis of curvature. Measurements of subtense can be estimated more reliably using 3D landmarks along the curve than using traditional techniques. We use equidistant semi-landmarks to quantify the curve because sliding the semi-landmarks masks the curvature signal. Principal components analysis of these equidistant semi-landmarks provides the added benefit of describing the shape of the curve. These results are promising for functional and forensic analysis of long bone curvature in modern human populations and in the fossil record. Am J Phys Anthropol, 2010. © 2010 Wiley-Liss, Inc. [source] Methods for calculating activity budgets compared: a case study using orangutansAMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2009Mark E. Harrison Abstract The results of comparisons of behavioral data between individuals, age,sex classes, seasons, sites and possibly even species may depend on sample size and the computational method used. To establish whether these are valid concerns, we compared results for percentage time spent feeding on major food types (fruit, leaves, flowers, invertebrates, bark, pith and other) for two orangutan populations in Sabangau (24 months) and Tuanan (29 months), Indonesian Borneo. Both the minimum follow limit included in analyses and the computational method used produced small, but statistically significant, differences in the results obtained, and the differences were more common for food types eaten less frequently. In addition, using different computational methods produced more significant differences than did including different minimum follow lengths in analyses. The computational method used also influenced the results of tests for differences in diet composition between age,sex classes. Thus, the method used can influence the results obtained and, hence, it is important to state explicitly the minimum follow limit included and computational method used to compile averages, and to ensure standardization in methods when comparing data between age,sex classes, time periods, field sites or species. Am. J. Primatol. 71:353,358, 2009. © 2008 Wiley-Liss, Inc. [source] Prevention of medication errors: detection and auditBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 6 2009Germana Montesi 1. Medication errors have important implications for patient safety, and their identification is a main target in improving clinical practice errors, in order to prevent adverse events. 2. Error detection is the first crucial step. Approaches to this are likely to be different in research and routine care, and the most suitable must be chosen according to the setting. 3. The major methods for detecting medication errors and associated adverse drug-related events are chart review, computerized monitoring, administrative databases, and claims data, using direct observation, incident reporting, and patient monitoring. All of these methods have both advantages and limitations. 4. Reporting discloses medication errors, can trigger warnings, and encourages the diffusion of a culture of safe practice. Combining and comparing data from various and encourages the diffusion of a culture of safe practice sources increases the reliability of the system. 5. Error prevention can be planned by means of retroactive and proactive tools, such as audit and Failure Mode, Effect, and Criticality Analysis (FMECA). Audit is also an educational activity, which promotes high-quality care; it should be carried out regularly. In an audit cycle we can compare what is actually done against reference standards and put in place corrective actions to improve the performances of individuals and systems. 6. Patient safety must be the first aim in every setting, in order to build safer systems, learning from errors and reducing the human and fiscal costs. [source] Altered cardiovascular vagal responses in nonelderly female patients with subclinical hyperthyroidism and no apparent cardiovascular diseaseCLINICAL ENDOCRINOLOGY, Issue 2 2007Renata Boschi Portella Summary Objective Subclinical hyperthyroidism (SH) has been associated with exercise intolerance, changes in cardiac morphology, atrial arrhythmias and sympathovagal imbalance. The aim of this study was to evaluate the vagal reserve and modulation by a sympathetic stimulus in nonelderly patients with SH without cardiovascular problems. Design We carried out a cross-sectional study, comparing data of the heart rate variability (HRV) of SH patients and healthy controls at rest and after vagal and sympathetic stimulation. Patients We studied 16 female patients with at least 6 months of SH and 16 healthy female controls with the same median age (40 vs. 34·5 years). Measurements We used the tilt test, with electrocardiographic record at rest, during the respiratory sinus arrhythmia (RSA) manoeuvre and after tilting, in order to analyse HRV in the frequency domain (%high frequency (HF) and low/high frequency ratio (LF/HF) using Biopotentials Captation System software. Results The median TSH level was 0·03 mU/l in patients and 1·37 mUI/l in controls. The median free T4 was 1·37 ng/dl in patients and 1·20 ng/dl in controls. Patients demonstrated a significantly smaller difference between %HF during the RSA and %HF at rest than controls (median ,7·5 vs. 36·6, P < 0·001). There was a lower difference between LF/HF ratio after tilting and LF/HF ratio at rest in patients than in controls (1·5 vs. 5·3, P = 0·005). Conclusion Subclinical hyperthyroidism affects cardiovascular autonomic balance in otherwise apparently healthy nonelderly females by blunting vagal responses. [source] | |||||||||||||||||||