Home About us Contact
|
Home About us Contact | ||
|
|
||
Strong Linear Relationship (strong + linear_relationship)
Selected AbstractsIntegrating physiology, population dynamics and climate to make multi-scale predictions for the spread of an invasive insect: the Argentine ant at Haleakala National Park, HawaiiECOGRAPHY, Issue 1 2010Stephen Hartley Mechanistic models for predicting species' distribution patterns present particular advantages and challenges relative to models developed from statistical correlations between distribution and climate. They can be especially useful for predicting the range of invasive species whose distribution has not yet reached equilibrium. Here, we illustrate how a physiological model of development for the invasive Argentine ant can be connected to differences in micro-site suitability, population dynamics and climatic gradients; processes operating at quite different spatial scales. Our study is located in the subalpine shrubland of Haleakala National Park, Hawaii, where the spread of Argentine ants Linepithema humile has been documented for the past twenty-five years. We report four main results. First, at a microsite level, the accumulation of degree-days recorded in potential ant nest sites under bare ground or rocks was significantly greater than under a groundcover of grassy vegetation. Second, annual degree-days measured where population boundaries have not expanded (456,521,degree-days), were just above the developmental requirements identified from earlier laboratory studies (445,degree-days above 15.9°C). Third, rates of population expansion showed a strong linear relationship with annual degree-days. Finally, an empirical relationship between soil degree-days and climate variables mapped at a broader scale predicts the potential for future range expansion of Argentine ants at Haleakala, particularly to the west of the lower colony and the east of the upper colony. Variation in the availability of suitable microsites, driven by changes in vegetation cover and ultimately climate, provide a hierarchical understanding of the distribution of Argentine ants close to their cold-wet limit of climatic tolerances. We conclude that the integration of physiology, population dynamics and climate mapping holds much promise for making more robust predictions about the potential spread of invasive species. [source] RAPA: a novel in vitro method to evaluate anti-bacterial skin cleansing productsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010S. A. Ansari Synopsis Development of efficacious anti-bacterial skin cleansing products has been limited by the availability of a pre-clinical (in vitro) method to predict clinical efficacy adequately. We report a simple and rapid method, designated as rapid agar plate assay (RAPA), that uses the bacteriological agar surface as a surrogate substrate for skin and combines elements of two widely used in vivo (clinical) methods (Agar Patch and Cup Scrub). To simulate the washing of the human hand or forearm skin with the test product, trypticase soy agar plates were directly washed with the test product and rinsed under running tap water. After air-drying the washed plates, test bacteria (Staphylococcus aureus or Escherichia coli) were applied and the plates were incubated at 37°C for 18,24 h. Using S. aureus as the test organism, anti-bacterial bar soap containing triclocarbanilide showed a strong linear relationship (R2 = 0.97) between bacterial dose and their per cent reduction. A similar dose-response relationship (R2 = 0.96) was observed for anti-bacterial liquid hand soap against E. coli. RAPA was able to distinguish between anti-bacterial products based on the nature and level of actives in them. In limited comparative tests, results obtained by RAPA were comparable with the results obtained by clinical agar patch and clinical cup scrub methods. In conclusion, RAPA provides a simple, rugged and reproducible in vitro method for testing the relative efficacy of anti-bacterial skin cleansing products with a likelihood of comparable clinical efficacy. Further testing is warranted to improve the clinical predictability of this method. Résumé Le développement des produits de nettoyage de peau antibactérienne efficace a été limité par la disponibilité d'une méthode (in vitro) préclinique pour prévoir en juste proportion l'efficacité clinique. Nous rapportons une méthode simple et rapide, indiquée comme analyse rapide de plat d'agar (RAPA) ce des utilisations la surface bactériologique d'agar comme substrat de remplacement pour la peau et combinons des éléments de deux méthodes (cliniques) in vivo employées couramment (correction d'agar et la tasse frottent). Pour simuler le lavage de la peau humaine de main ou d'avant-bras avec le produit d'essai, des plats de l'agar de soja de trypticase ont été directement lavés avec le produit d'essai et rincés sous l'eau du robinet courante. Après l'air séchant les plats lavés, les bactéries d'essai (S. doré Ou Escherichia coli) étaient appliquées et des plats ont été incubées au °C 37 pendant 18,24 heures. Utilisant S. doré Comme organization d'essai, le triclocarbanilide contenant du savon de barre antibactérienne a montré un rapport linéaire fort (R2 = 0.97) entre la dose bactérienne et leur réduction de pour cent. On a observé un rapport semblable de réponse à dose donnée (R2 = 0.96) pour le savon liquide antibactérien de main contre E. coli. RAPA pouvait distinguer les produits antibactériens basés sur la nature et le niveau des actives dans eux. Dans les essais comparatifs limités, résultats obtenus par RAPA étaient comparables aux résultats obtenus par la correction clinique d'agar et la tasse clinique frottent des méthodes, en conclusion, RAPA fournit à une méthode in vitro simple, raboteuse et reproductible pour examiner l'efficacité relative des produits de nettoyage de peau antibactérienne la probabilité de l'efficacité clinique comparable. Davantage d'essai est justifié pour améliorer la prévisibilité clinique de cette méthode. [source] Are local patterns of anthropoid primate diversity related to patterns of diversity at a larger scale?JOURNAL OF BIOGEOGRAPHY, Issue 6 2000M. J. Lawes Abstract Aims, (1) To determine the relationship between local and regional anthropoid primate species richness. (2) To establish the spatial and temporal scale at which the ultimate processes influencing patterns of primate species coexistence operate. Location Continental landmasses of Africa, South America and Asia (India to China, and all islands as far south as New Guinea). Methods, The local,regional species richness relationship for anthropoid primates is estimated by regressing local richness against regional richness (independent variable). Local richness is estimated in small, replicate local assemblages sampled in regions that vary in total species richness. A strong linear relationship is taken as evidence that local assemblages are unsaturated and local richness results from proportional sampling of the regional pool. An asymptotic curvilinear relationship is interpreted to reflect saturated communities, where strong biotic interactions limit local richness and local processes structure the species assemblage. As a further test of the assumption of local assemblage saturation, we looked for density compensation in high-density local primate assemblages. Results, The local,regional species richness relationship was linear for Africa and South America, and the slope of the relationship did not differ between the two continents. For Asia, curvilinearity best described the relationship between local and regional richness. Asian primate assemblages appear to be saturated and this is confirmed by density compensation among Asian primates. However, density compensation was also observed among African primates. The apparent assemblage saturation in Asia is not a species,area phenomenon related to the small size of the isolated islands and their forest blocks, since similar low local species richness occurs in large forests on mainland and/or peninsular Asia. Main conclusions In Africa and South America local primate assemblage composition appears to reflect the influence of biogeographic processes operating on regional spatial scales and historical time scales. In Asia the composition of primate assemblages are by-and-large subject to ecological constraint operating over a relatively small spatial and temporal scale. The possible local influence of the El Niño Southern Oscillations on the evolution and selection of life-history characteristics among Asian primates, and in determining local patterns of primate species coexistence, warrants closer inspection. [source] The Association of Alcohol-Induced Blackouts and Grayouts to Blood Alcohol ConcentrationsJOURNAL OF FORENSIC SCIENCES, Issue 4 2006Paul J. Perry Ph.D. ABSTRACT: The primary aim of this study was to investigate the association between measured blood alcohol concentration (BAC) and the presence and degree of amnesia (no amnesia, grayout, or blackout) in actively drinking subjects. A secondary aim was to determine potential factors other than BAC that contribute to the alcohol-induced memory loss. An interview questionnaire was administered to subjects regarding a recent alcohol associated arrest with a documented BAC greater than 0.08 g/dL for either public intoxication, driving under the influence, or under age drinking was administered. Demographic variables collected included drinking history, family history of alcoholism, presence of previous alcohol-related memory loss during a drinking episode, and drinking behavior during the episode. Memory of the drinking episode was evaluated to determine if either an alcohol-induced grayout (partial anterograde amnesia) or blackout (complete anterograde amnesia) occurred. Differences in (1) mean total number of drinks ingested before arrest, (2) gulping of drinks, and (3) BAC at arrest were found for those having blackouts compared with no amnesia; while differences in drinking more than planned were found between the no amnesia and grayout groups. A strong linear relationship between BAC and predicted probability of memory loss, particularly for blackouts was obvious. This finding clinically concludes that subjects with BAC of 310 g/dL or greater have a 0.50 or greater probability of having an alcoholic blackout. [source] Behavior of fully filled regions in a non-intermeshing twin-screw extruderPOLYMER ENGINEERING & SCIENCE, Issue 8 2003Rajath Mudalamane Twin-screw extruders are operated with sequential filled and partially filled regions in order to perform the required unit processes. Channel fill length, defined as the length of fully filled regions in an extrusion screw, is gaining importance as a design parameter because of its implications on residence time distribution, distributive and dispersive mixing, and also process stability. A detailed study,experimental and theoretical,of the behavior of fill lengths in response to operating conditions (throughput, screw speed) and screw geometry is presented in this paper. Mean residence times were also measured for each geometry and operating condition. The apparatus consisted of a non-intermeshing counter-rotating twin-screw extruder (NITSE) with a transparent (acrylic) barrel, fed with corn syrup (Newtonian at room temperature). Fill length exhibits a nonlinear relationship with specific throughput (Q/N), with the slope increasing monotonously as the throughput Q increases at a given screw speed N. The mean residence time exhibits a strong linear relationship with inverse specific throughput and inverse fill length. A theoretical model was developed to predict the filled length based on pressure-throughput relationships taken from literature for this system, and the predictions were found to agree very well with experimental observations. [source] Crystalline study of amorphous poly(ethylene terephthalate) sheets through annealingASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009Ruey-Shi Tsai Abstract Poly(ethylene terephthalate) (PET) sheets of different crystallinity were obtained by annealing. The annealed PET sheets were characterized by the density measurement, differential scanning calorimetry (DSC), ultraviolet (UV)-visible spectrometry, X-ray diffraction, and infrared (IR) spectrometry. The density data can be used as a basic measurement of the degree of crystallinity. The total transition heat data obtained from the first run DSC heating curves can correlate with the crystallinity, although it may underestimate the crystallinity for those samples with higher crystallinity. The visible light transmittance data can be related to the crystallinity, and are very sensitive to the change of the crystallinity for the PET sheets of low crystallinity. The X-ray diffraction data and IR transmittance data do not show strong linear relationship to the crystallinity in a quantitative way. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||