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Physical Factors (physical + factor)
Selected AbstractsEFFECT OF PHYSICAL FACTORS ON ACETIC ACID PRODUCTION IN BRETTANOMYCES STRAINSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2005C. CASTRO-MARTINEZ ABSTRACT Four species of Brettanomyces (intermedius, bruxellensis, custersianus, clausenii) were examined to ascertain their acetic acid production capacity. The results showed that B. bruxellensis was the strain with the best volumetric productivity ,and ,specific ,production ,rate ,(P = 0.065 gL,1 h,1; ,Vp = 0.43 gg,1h,1). The best kinetic parameters were reached (P = 0.133 gL,1 h,1; Yp/s = 0.23; Pmax = 11.64 gL,1) ,at ,an ,airflow ,of ,288 Lh,1,(0.6 vvm, ,OTR = 124 mgO2L,1,h,1), and substrate inhibition was not observed. The influence of temperature and agitation on acetic acid production by B. bruxellensis in a glucose medium was investigated at different levels, 26, 30, 34C and 250, 350, 450 rpm, respectively. Temperature and agitation were shown to be deci-sive factors (P < 0.05) in acetic acid production at 288 Lh,1(0.6 vvm, OTR = 124 mgO2L,1 h). The optimal conditions for a high volumetric productivity were 30C and 250 rpm, respectively. [source] DO PHYSICAL FACTORS REGULATE PHYTOPLANKTON DISTRIBUTION PATTERNS IN LARGE, SHALLOW LAKES?JOURNAL OF PHYCOLOGY, Issue 2000H.J. Carrick Factors that regulate phytoplankton dynamics in shallow, productive lakes are poorly understood, due to their predisposition for frequent algal blooms and sediment resuspension events. In Lake Apopka, greatest phytoplankton biomass reflects wind-induced resuspension of algae (meroplankton) that exists on the aphotic lake bottom in a layer approximately 5 cm thick; this assemblage is dominated by diatoms (>60% of total biomass) that can occur in resting stages. Once exposed to moderate light, meroplankton are capable of growth and photosynthetic rates comparable with surface populations. In Lake Okeechobee, remote sensing was used to assess the basin-wide distribution of suspended particles. Satellite reflectance values agreed well with in situ particle densities at 20 in-lake stations (average r2; LANDSAT = 0.81, AVHRR = 0.53), and maps of algal blooms (r2 = 0.79, p , 0.01). The greatest chlorophyll concentrations occurred in the vicinity of tributary nutrient inputs at the lake's perimeter, while turbidity increased towards the center of the lake reflecting predominant water circulation patterns. These results underscore the importance of physical-biological interactions in lakes. [source] Prevalence of Sexual Problems and Its Association with Social, Psychological and Physical Factors among Men in a Malaysian Population: A Cross-Sectional StudyTHE JOURNAL OF SEXUAL MEDICINE, Issue 1 2008Kia Fatt Quek PhD ABSTRACT Introduction., Sexual problems are common in the general population. Studies have shown that most of these sexual problems are related to their social lives, medical illnesses, and psychological status. Among the sexual problems in men, premature ejaculation (PE) is one of the most frequent, yet it is the least well-understood of the sexual dysfunctions of men. Aim., To determine the prevalence of sexual problem particularly PE and erectile dysfunction (ED) among people living in urban areas and to investigate the characteristics associated with these sexual problems in a Malaysian population. Main Outcome Measure., The PE which is defined as an intravaginal ejaculation latency time less than 2 minutes was assessed in the ED and non-ED group. Methods., The Hospital Anxiety and Depression scale is used as a measure of the psychological status [30]. The ED status was assessed using the International Index of Erectile Function questionnaire. Results., The prevalence of self-reported sexual problems for ED and PE were 41.6% and 22.3%, respectively. In those subjects with ED, 33.5% reported to have PE. Of the total of 430 subjects, anxiety was present in 8.1%, while depression was 5.3%. The prevalence of PE accounted for 25% anxiety and 14.6% for depression respectively in the population. EDs were associated with diabetes and hypertension (OR [95% CI]: 5.33 [2.33, 10.16], 3.40 [1.76, 6.57], P < 0.05), respectively, while factors associated with PE were anxiety and depression (OR [95% CI]: 1.29 [0.68, 2.45], 1.39 [0.69, 2.78]), respectively. Conclusion., Prevalence of ED is associated with medical symptoms such as diabetes and hypertension and a rise in the prevalence of age while psychological distress such as anxiety and depression also contribute to a higher PE rate. Quek KF, Sallam AA, Ng CH, and Chua CB. Prevalence of sexual problems and its association with social, psychological and physical factors among men in a Malaysian Population: A cross-sectional study. J Sex Med 2008;5:70,76. [source] Ultrasound parameters of bone health and related physical measurement indicators for the community-dwelling elderly in JapanGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 2 2007Wei Sun Deteriorated bone strength, which approaches osteoporosis, increases the likelihood that an elderly person will not able to live independently. However, few data are available pertaining to bone health and various physical objective indicators. The aim of the present study was to objectively assess bone health by quantitative ultrasound (QUS) and identify related physical measurement indicators among the elderly to aid the health promotion strategies in Japan. A cross-sectional study was performed at five welfare centers for the aged in the suburban area of Takatsuki city, Japan. Subjects comprised community-dwelling persons (134 men, 240 women) aged ,60 years and registered at welfare centers. QUS of the right-heel was conducted and recorded as stiffness index (SI). Physical factors including body components (fat and muscle mass), handgrip strength, daily physical activity, daily walking steps, maximum and usual walking speed and maximum bite force were examined objectively during the period May,June 2005. SI in women was lower than that in men (P < 0.01) and decreased significantly with age (P < 0.01). The SI correlated with six physical items in men and with all items in women. Multiple linear regression analysis showed that muscle mass, usual walking speed and maximum bite force were the strongest physical indicators of male SI; and muscle mass, maximum walking speed and maximum bite force were the strongest indicators of female SI. Muscle training, daily walking exercise and oral health care should be included in health promotion programs for the bone health of elderly women and men in Japan. [source] Individual and combined impacts of biomechanical and work organization factors in work-related musculoskeletal symptoms,,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2003Grant D. Huang MPH Abstract Background Investigations of work-related low back (LB) and upper extremity (UE) disorders have increasingly utilized multivariable models that include biomechanical/physical and work organization factors. However, the nature of any interactive effects is not well understood. Methods Using questionnaires, high and low exposure groups for biomechanical/physical factors, cognitive demands, cognitive processing, interpersonal demands, participatory management, skill discretion, and time pressure for 289 individuals (U.S. Marines) were identified. Musculoskeletal symptom status was also determined by questionnaire. Individual and biomechanical,psychosocial combinations were examined in adjusted multivariable logistic regression analyses. Results Time pressure was associated with both LB and UE symptoms (odds ratio(s) (OR) range,=,2.13,3.09), while higher biomechanical exposures were risk factors for LB symptoms (OR,=,2.07; 95% confidence intervals (CI): 1.00,4.35) and concurrent LB and UE symptoms (OR,=,2.80; CI: 1.35,5.83). Greater risks for concurrent LB and UE symptoms were indicated for combinations involving higher biomechanical exposure and: time pressure (OR,=,2.21; CI: 1.19,4.10); cognitive demands (OR,=,2.25; CI: 1.23,4.09); cognitive processing (OR,=,2.08; CI: 1.16,3.75); interpersonal demands (OR,=,2.44; CI: 1.35,4.41); participatory management (OR,=,2.50; CI: 1.30,4.81). Results did not suggest any interaction between biomechanical and work organization factors. Conclusions While no synergism was indicated, the present findings emphasize the need to consider both biomechanical factors and specific work organization factors, particularly time pressure, in reducing musculoskeletal-related morbidity. Am. J. Ind. Med. 43:495,506, 2003. Published 2003 Wiley-Liss, Inc. [source] Changes in gravitational force cause changes in gene expression in the lens of developing zebrafishDEVELOPMENTAL DYNAMICS, Issue 10 2006Naoko Shimada Abstract Gravity has been a constant physical factor during the evolution and development of life on Earth. We have been studying effects of simulated microgravity on gene expression in transgenic zebrafish embryos expressing gfp under the influence of gene-specific promoters. In this study, we assessed the effect of microgravity on the expression of the heat shock protein 70 (hsp70) gene in lens during development using transgenic zebrafish embryos expressing gfp under the control of hsp70 promoter/enhancer. Hsp70:gfp expression was up-regulated (45%) compared with controls during the developmental period that included the lens differentiation stage. This increase was lens specific, because the entire embryo showed only a 4% increase in gfp expression. Northern blot and in situ hybridization analysis indicated that the hsp70:gfp expression recapitulated endogenous hsp70 mRNA expression. Hypergravity exposure also increased hsp70 expression during the same period. In situ hybridization analysis for two lens-specific crystallin genes revealed that neither micro- nor hypergravity affected the expression level of ,B1 - crystallin, a non-hsp gene used as a marker for lens differentiation. However, hypergravity changed the expression level of ,A - crystallin, a member of the small hsp gene family. Terminal deoxynucleotidyl transferase,mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) assay analysis showed that altered-gravity (,g) decreased apoptosis in lens during the same period and the decrease correlated with the up-regulation of hsp70 expression, suggesting that elimination of nuclei from differentiating lens fiber cells was suppressed probably through hsp70 up-regulation. These results support the idea that ,g influences hsp70 expression and differentiation in lens-specific and developmental period specific manners and that hsp family genes play a specific role in the response to ,g. Developmental Dynamics 235:2686,2694, 2006. © 2006 Wiley-Liss, Inc. [source] Modeling of a continuous rotary reactor for carbon nanotube synthesis by catalytic chemical vapor depositionAICHE JOURNAL, Issue 3 2009Sophie L. Pirard The modeling of carbon nanotube production by the CCVD process in a continuous rotary reactor with mobile bed was performed according to a rigorous chemical reaction engineering approach. The geometric, hydrodynamic, physical and physicochemical factors governing the process were analyzed in order to establish the reactor equations. While the study of the hydrodynamic factor suggests a co-current plug-flow approximation, the physical factor mainly deals with the phenomena of transport and the transfer of mass, which can be neglected. Concerning the physicochemical factor, the modeling is based on knowledge of the expression of the initial reaction rate, and takes into account catalytic deactivation as a function of time, according to a sigmoid decreasing law. The reactor modeling allows obtaining the evolution of partial pressure, carbon nanotube production and catalytic deactivation along the reactor for given initial operating conditions. The comparison between experimental and calculated production highlights a very good fit of data. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Nonanoic acid , an experimental irritantCONTACT DERMATITIS, Issue 3 2003Jan E. Wahlberg Irritant contact dermatitis is defined as a non-immunological skin reaction following exposure to various chemical, mechanical and physical factors. It is known that the skin response to irritants depends on the irritant applied and differs between chemically different irritants. Sodium lauryl sulfate (SLS) is an anionic detergent and the most frequently used substance in experimental irritant contact dermatitis. In 1980, it was suggested that nonanoic acid (NNA) could be used as a positive control when patch testing. Since then, NNA has been used as an experimental irritant in several studies and has been used as a chemically different substance compared to SLS. The present article presents a review of the application of NNA in studies on skin irritancy and experimental irritant contact dermatitis. [source] Increased lifetime prevalence of dental trauma is associated with previous non-dental injuries, mental distress and high alcohol consumptionDENTAL TRAUMATOLOGY, Issue 1 2001U. Perheentupa Abstract , The purpose of the study was to assess the lifetime prevalence of dental injuries and risk factors involved in a general population-based birth cohort. The study population consisted of 5737 subjects who had participated in a health survey at the age of 31 years. Altogether 52% of the participants were women. This partly computer-based health survey included two questionnaires on previous dental and non-dental injuries, general health, occupational status and lifestyle. The current study was based on these questionnaires. The lifetime prevalence of dental fractures was 43% and the lifetime prevalence of dental luxations and exarticulations 14%. Men more commonly had dental injuries than women. Particularly mental distress and a history of previous injuries were shown to increase the risk for dental injuries. Furthermore, overweight and high alcohol consumption were positively associated with a high lifetime prevalence of tooth trauma. Regular physical activity decreased trauma occurrence. Socioeconomic status further affected the lifetime prevalence of dental injuries. The conclusion of the study was that personal, social and physical factors played a role in the occurrence of dental trauma. [source] Schizophrenia and physical health problemsACTA PSYCHIATRICA SCANDINAVICA, Issue 2009Y. Von Hausswolff-Juhlin Objective:, To estimate the prevalence of physical health problems in patients with schizophrenia, and to appraise the impact on mortality rates and quality of life (QoL) in such patients. Method:, A selective review of clinical articles relating to physical health such as cardiovascular disease, metabolic syndrome and QoL. In addition, current guidelines and recommendations for the monitoring of physical health in schizophrenia were reviewed. Results:, Cardiovascular events contribute most strongly to the excess mortality observed in schizophrenia. Other factors that contribute significantly include obesity, metabolic aberrations, smoking, alcohol, lack of exercise and poor diet , all of which might be targets for health promoting activities. Conclusion:, Physical health problems in patients with schizophrenia are common, and contribute to the excess mortality rate, as well as decreasing QoL. Many adverse physical factors are malleable in such patients, and physical benefit may be gained by following practical guidelines for their monitoring and improvement. [source] Atlantic climatic factors control decadal dynamics of a Baltic Sea copepod Temora longicornisECOGRAPHY, Issue 5 2003Jari Hänninen We discovered, using transfer functions, that climatic changes in the Atlantic control the abundance of Temora longicornis, a dominant pelagic copepod of the Baltic Sea. The seawater salinity was increasing and copepod numbers were high from 1960s up to 1970s. Then the freshwater runoff started to increase, which resulted in decreasing salinities and abundance of the copepod. At the end of 1990s, runoffs remained at a high level, and the decrease of surface salinities and Temora leveled off. Due to time lags between variables studied, we also make predictions of changes expectable in early 2000s. The total freshwater runoff to the Baltic Sea followed the North Atlantic Oscillation with an immediate lag. Salinity followed the runoff non-linearly with a lag of 4,9 months. Temora longicornis followed the salinity with a lag of 1,3 months. Predicted abundance of T. longicornis will remain low implicating poor feeding conditions for planktivores. Our study points out the importance of physical factors in control of pelagic environments compared to ecological interactions, such as top-down and bottom-up. [source] Insect community organisation in estuaries: the role of the physical environmentECOGRAPHY, Issue 3 2002D. Dudley Williams Insects are reportedly uncommon in marine habitats and, from a spatial/temporal intercomparison perspective, estuaries are among the least studied. We examined the natural variability seen among insect community organisation in estuaries on both sides of the North Atlantic, and evaluated the role of their physical environments. Community composition was found to be strongly influenced by three physical factors: estuary size, the degree of inundation by incoming tides, and substrate size/stability. Insects formed a significant proportion (17,54%, by numbers) of the benthic community of coarse-grained-substratum estuaries, and species richness increased with estuary size. Nymphs/larvae of mayflies, stoneflies, caddisflies, elmid beetles and chironomids dominated channel sites inundated by up to 25% of all incoming tides, but a gradual loss in species richness occurred downstream. However, even the most seaward sites supported high insect densities (up to 25,016 and 5433 m,2, supporting 26 and 4 species, at sites inundated by 75 and 100% of all incoming tides, respectively). Sites covered by tides for between 3 and 5 h twice daily were dominated by orthocladine chironomids, especially of the genus Orthocladius. Chironomid larvae contribute significantly to the diets of some coastal fish species, particularly juvenile flounder and sticklebacks. We present a schematic model summarising the relationships between estuary size, degree of inundation by salt water and insect community structure. [source] Environmental epigenomics in human health and diseaseENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2008Dana C. Dolinoy Abstract The epigenome consists of the DNA methylation marks and histone modifications involved in controlling gene expression. It is accurately reproduced during mitosis and can be inherited transgenerationally. The innate plasticity of the epigenome also enables it to be reprogrammed by nutritional, chemical, and physical factors. Imprinted genes and metastable epialleles represent two classes of genes that are particularly susceptible to environmental factors because their regulation is tightly linked to epigenetic mechanisms. To fully understand the etiology of the most devastating diseases that plague humans, the full complexity of the human epigenome will ultimately need to be characterized. Moreover, the elucidation of the interaction of the environment with the epigenome should allow for the development of novel epigenetic-based diagnostic, prevention, and therapeutic strategies for human diseases. Herein, we introduce the emerging field of environmental epigenomics, discuss the importance of imprinted genes and metastable epialleles as epigenetically labile genomic targets, and endorse the genome-wide identification of the full suite of epigenetically labile targets in both the mouse and human genomes. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc. [source] Archaeal diversity and a gene for ammonia oxidation are coupled to oceanic circulationENVIRONMENTAL MICROBIOLOGY, Issue 4 2009Pierre E. Galand Summary Evidence of microbial zonation in the open ocean is rapidly accumulating, but while the distribution of communities is often described according to depth, the other physical factors structuring microbial diversity and function remain poorly understood. Here we identify three different water masses in the North Water (eastern Canadian Arctic), defined by distinct temperature and salinity characteristics, and show that they contained distinct archaeal communities. Moreover, we found that one of the water masses contained an increased abundance of the archaeal alpha-subunit of the ammonia monooxygenase gene (amoA) and accounted for 70% of the amoA gene detected overall. This indicates likely differences in putative biogeochemical capacities among different water masses. The ensemble of our results strongly suggest that the widely accepted view of depth stratification did not explain microbial diversity, but rather that parent water masses provide the framework for predicting communities and potential microbial function in an Arctic marine system. Our results emphasize that microbial distributions are strongly influenced by oceanic circulation, implying that shifting currents and water mass boundaries resulting from climate change may well impact patterns of microbial diversity by displacing whole biomes from their historic distributions. This relocation could have the potential to establish a substantially different geography of microbial-driven biogeochemical processes and associated oceanic production. [source] Hypolithic community shifts occur as a result of liquid water availability along environmental gradients in China's hot and cold hyperarid desertsENVIRONMENTAL MICROBIOLOGY, Issue 2 2007Stephen B. Pointing Summary Hypolithic cyanobacterial communities occur in hot and cold hyperarid environments but the physical factors determining their diversity are not well understood. Here we report hypolithic diversity and colonization of a common quartz substrate at several hyperarid locations in the ancient deserts of north-western China, that experience varying mean annual temperature, rainfall and concomitant availability of liquid water in soil. Microscopy and enrichment culture resulted only in Chroococcidiopsis morphotypes which were ubiquitous, but community phylogenetic analysis revealed considerable cyanobacterial and heterotrophic bacterial diversity. Species Richness and Shannon's Diversity Index displayed a significant positive linear correlation with availability of liquid water but not temperature or rainfall alone. Several taxonomic groups occurred only in specific climatically defined locations, while for Chroococcidiopsis, Deinococcus and Phormidium location specific lineages within these genera were also evident. Multivariate analysis was used to illustrate pronounced community shifts due to liquid water availability, although these did not significantly affect the predicted functional relationships within any given assemblage in either hot or cold, wet or dry hyperarid deserts. This study clearly demonstrates that availability of liquid water, rather than temperature or rainfall per se is the key determinant of hypolithic diversity in hyperarid locations, and furthermore that functionally similar yet taxonomically distinct communities occur, characterized by the presence of taxa that are specific to defined levels of aridity. [source] Antimicrobial peptides and proteins, exercise and innate mucosal immunityFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2006Nicholas P. West Abstract This review examines the question of whether exercise can be used as an experimental model to further our understanding of innate antimicrobial peptides and proteins (AMPs) and their role in susceptibility to infection at mucosal surfaces. There is strong evidence to suggest that AMPs, in combination with cellular and physical factors, play an important role in preventing infection. Although AMPs act directly on microorganisms, there is increasing recognition that they also exert their protective effect via immunomodulatory mechanisms, especially in noninflammatory conditions. Further studies that manipulate physiologically relevant concentrations of AMPs are required to shed light on the role they play in reducing susceptibility to infection. Evidence shows that in various form prolonged and/or exhaustive exercise is a potent modulator of the immune system, which can either sharpen or blunt the immune response to pathogens. The intensity and duration of exercise can be readily controlled in experimental settings to manipulate the degree of physical stress. This would allow for an investigation into a potential dose,response effect between exercise and AMPs. In addition, the use of controlled exercise could provide an experimental model by which to examine whether changes in the concentration of AMPs alters susceptibility to illness. [source] Distribution of minke whales in the Bellingshausen and Amundsen Seas (60°W,120°W), with special reference to environmental/physiographic variablesFISHERIES OCEANOGRAPHY, Issue 3 2000Fujio Kasamatsu The relationship between the distribution of minke whales (Balaenoptera acutorostrata) in the Bellingshausen and Amundsen Seas (longitude between 60°W and 120°W), and environmental and physiographic variables (sea-surface temperature, sea-ice extension, and sea-floor-slope type), was studied to determine whether these environmental and physical factors affect the distribution and density of minke whales. The analysis was based on sightings data obtained from the 1989/90 and 1982/83 IWC/IDCR cruises. The mean sea-surface temperatures for comparable areas were significantly higher in 1989/90 (2.04°C) than in 1982/83 (1.12°C), and the area where the sea-surface temperature was greater than 1°C in the 1989/90 study was approximately twice that of the 1982/83 study. Additionally, during the surveys, the extent of the sea ice in 1989/90 was less than that in 1982/83, with the mean ice edge about 92.6 km (50 nautical miles; 1 nautical mile ,1.852 km) farther south in 1989/90 than in 1982/83. This is consistent with the sea ice extent observed in winter, when the sea ice extent was less in 1989 than in 1982. The distribution of minke whales was substantially different between the two surveys, with the density and abundance of minke whales being greater in 1982/83 than in 1989/90. The warmer sea-surface temperatures, fewer cold-water intrusions, and the smaller extent of sea ice in 1989/90 may be related to the difference in distribution of minke whales from 1982/83, possibly owing to the shift in availability of prey. [source] Modification of the diel vertical migration of Bythotrephes longimanus by the cold-water planktivore, Coregonus artediFRESHWATER BIOLOGY, Issue 5 2008JOELLE D. YOUNG Summary 1. The weak diel vertical migration observed in the large cladoceran Bythotrephes longimanus seems contradictory to the predator-avoidance hypothesis that predicts large zooplankton should have long migration amplitudes. However, cold-water planktivores, especially Coregonus spp., are a main source of mortality for Bythotrephes and hence a deeper migration would result in a greater overlap with these hypolimnetic planktivores. We hypothesized that Coregonus artedi (cisco) modifies the normal vertical migration pattern of Bythotrephes, such that the latter stays higher in the water column during the day and thus migrates less extremely at night. 2. The vertical distribution of Bythotrephes during the day was determined from single visits to six lakes in Ontario, Canada, all of which contain warm-water, epilimnetic planktivores but differing in whether they contain cisco. One lake of each fish type was sampled day and night every 2,3 weeks over the ice-free season to examine daytime depths and migration amplitude. 3. The vertical migration of Bythotrephes differed in the presence and absence of cisco. In the lakes with cisco, there were significantly fewer Bythotrephes in the hypolimnion and they were higher in the water column during the day. Migration amplitude was smaller in the cisco than in the non-cisco lake. These observations were not attributable to differences in physical factors, and, although not conclusively attributable to cisco, are consistent with an effect of cisco. 4. We suggest that diurnal depth selection by Bythotrephes in lakes containing cisco is a trade-off between the risk of predation by warm- versus cold-water predators, balanced by the benefits of increased temperature and feeding rates near the surface. Even in lakes without cisco, however, the vertical migration of Bythotrephes was less than expected, suggesting that diurnal depth selection is a balance between the risk from warm-water planktivores and access to sufficient light to feed effectively. [source] The influence of scale and geography on relationships between stream community composition and landscape variables: description and predictionFRESHWATER BIOLOGY, Issue 5 2003Colin R. Townsend SUMMARY 1.,We analysed an existing database of macroinvertebrates and fish in the context of a newly established geographical information system (GIS) of physical features to determine the relationships between stream community composition and physical factors measured at three landscape scales , catchment, reach and bedform. Both an exploratory (concordance analysis) and a predictive (ausrivas) approach were used. 2.,The environmental variables that most successfully accounted for variation in macroinvertebrate assemblages were mainly ,natural' and at the catchment-scale (relief ratio, basin diameter, etc.) but the human-induced physical setting of percentage of pasture in the riparian zone was also influential. For fish, ,natural' variables were also dominant, but these were mostly at the bedform or reach scales and land use featured strongly. 3.,Geographic location accounted for some of the variation in invertebrate assemblages, partly because geography and influential conditions/resources are correlated but also because different species may have evolved in different places and have not colonised every ,ecologically appropriate' location. Geographic location was not influential in accounting for variation in assemblages of strongly flying invertebrates, supporting the hypothesis that organisms having high dispersal potential can be expected to break down geographic barriers more readily than those with poor dispersal powers. In accord with what is known about the local evolution and restricted distributions of native and exotic species, history (reflected in geography) appeared to account for some variation in fish assemblages. 4.,Given their different mathematical bases, the fact that exploratory and predictive analyses yielded similar results provides added confidence to our conclusions. [source] Competitive ability and the coexistence of anuran larvae in freshwater rock-poolsFRESHWATER BIOLOGY, Issue 2 2000Anssi Laurila Summary 1I examined the competitive ability of larval common frogs (Rana temporaria) and common toads (Bufo bufo) in a laboratory experiment by manipulating the number and size of Rana and the number of Bufo. 2Bufo was the most active tadpole type, whereas small Rana was more active than large Rana. 3Especially at high food availability, the growth rate of large Rana at metamorphosis was reduced in the presence of small Rana, whereas that of small Rana was not affected by larger conspecifics. 4Both size classes of Rana were negatively affected by the presence of Bufo. Size at metamorphosis of Bufo was greater when large Rana was present. These results suggest that activity level is important in determining competitive ability. 5To study competition in the field, tadpoles of Bufo were introduced to small rock-pools that did not support Bufo naturally, but were with or without Rana. 6In the experimental pools, there were no interspecific effects on the growth rate of either species. However, the growth rate of Bufo was lower in the experimental pools than in pools inhabited naturally. Futher, survival of Bufo was low in small pools. Lower food availability or physical factors associated with small pools, rather than interspecific competition, may be the reason why Bufo avoids breeding in small rock-pools. [source] Climate change hastens the turnover of stream fish assemblagesGLOBAL CHANGE BIOLOGY, Issue 10 2008LAËTITIA BUISSON Abstract Stream fish are expected to be significantly influenced by climate change, as they are ectothermic animals whose dispersal is limited within hydrographic networks. Nonetheless, they are also controlled by other physical factors that may prevent them moving to new thermally suitable sites. Using presence,absence records in 655 sites widespread throughout nine French river units, we predicted the potential future distribution of 30 common stream fish species facing temperature warming and change in precipitation regime. We also assessed the potential impacts on fish assemblages' structure and diversity. Only cold-water species, whose diversity is very low in French streams, were predicted to experience a strong reduction in the number of suitable sites. In contrast, most cool-water and warm-water fish species were projected to colonize many newly suitable sites. Considering that cold headwater streams are the most numerous on the Earth's surface, our results suggested that headwater species would undergo a deleterious effect of climate change, whereas downstream species would expand their range by migrating to sites located in intermediate streams or upstream. As a result, local species richness was forecasted to increase greatly and high turnover rates indicated future fundamental changes in assemblages' structure. Changes in assemblage composition were also positively related to the intensity of warming. Overall, these results (1) stressed the importance of accounting for both climatic and topographic factors when assessing the future distribution of riverine fish species and (2) may be viewed as a first estimation of climate change impacts on European freshwater fish assemblages. [source] Controls on surface water chemistry in two lake-watersheds in the Adirondack region of New York: differences in nitrogen solute sources and sinksHYDROLOGICAL PROCESSES, Issue 10 2007Mari Ito Abstract The southwestern Adirondack region of New York receives among the highest rates of atmospheric nitrogen (N) deposition in the USA. Atmospheric N deposition to sensitive ecosystems, like the Adirondacks, may increase the acidification of soils through losses of exchangeable nutrient cations, and the acidification of surface waters associated with enhanced mobility of nitrate (NO3,). However, watershed attributes, including surficial terrestrial characteristics, in-lake processing, and geological settings, have been found to complicate the relationships between atmospheric N deposition and N drainage losses. We studied two lake-watersheds in the southwestern Adirondacks, Grass Pond and Constable Pond, which are located in close proximity (,26 km) and receive similarly high N deposition, but have contrasting watershed attributes (e.g. wetland area, geological settings). Since the difference in the influence of N deposition was minimal, we were able to examine both within- and between-watershed influences of land cover, the contribution of glacial till groundwater inputs, and in-lake processes on surface water chemistry with particular emphasis on N solutes and dissolved organic carbon (DOC). Monthly samples at seven inlets and one outlet of each lake were collected from May to October in 1999 and 2000. The concentrations of NO3, were high at the Grass Pond inlets, especially at two inlets, and NO3, was the major N solute at the Grass Pond inlets. The concentrations of likely weathering products (i.e. dissolved Si, Ca2+, Mg2+, Na+) as well as acid neutralizing capacity and pH values, were also particularly high at those two Grass Pond inlets, suggesting a large contribution of groundwater inputs. Dissolved organic N (DON) was the major N solute at the Constable Pond inlets. The higher concentrations of DON and DOC at the Constable Pond inlets were attributed to a large wetland area in the watershed. The DOC/DON ratios were also higher at the Constable Pond inlets, possibly due to a larger proportion of coniferous forest area. Although DON and DOC were strongly related, the stronger relationship of the proportion of wetland area with DOC suggests that additional factors regulate DON. The aggregated representation of watershed physical features (i.e. elevation, watershed area, mean topographic index, hypsometric-analysis index) was not clearly related to the lake N and DOC chemistry. Despite distinctive differences in inlet N chemistry, NO3, and DON concentrations at the outlets of the two lakes were similar. The lower DOC/DON ratios at the lake outlets and at the inlets having upstream ponds suggest the importance of N processing and organic N sources within the lakes. Although an inverse relationship between NO3, and DOC/DON has been suggested to be indicative of a N deposition gradient, the existence of this relationship for sites that receive similar atmospheric N deposition suggest that the relationship between NO3, and the DOC/DON ratio is derived from environmental and physical factors. Our results suggest that, despite similar wet N deposition at the two watershed sites, N solutes entering lakes were strongly affected by hydrology associated with groundwater contribution and the presence of wetlands, whereas N solutes leaving lakes were strongly influenced by in-lake processing. Copyright © 2006 John Wiley & Sons, Ltd. [source] Review Article: A new wrinkle on old skin: the role of elastic fibres in skin ageingINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2010A. K. Langton Synopsis Cutaneous ageing is the result of two distinct, biological processes which may occur concurrently: (i) the passage of time, termed intrinsic ageing and (ii) environmental influences, termed extrinsic ageing. Intrinsic ageing of the skin is a slow process which causes changes in tissue structure and impairs function in the absence of additional biological, chemical and physical factors. The clinical features of intrinsically aged skin are not usually evident until old age when, although smooth and unblemished, the skin surface appears pale and is characterized by fine wrinkles with occasional exaggerated expression lines. Functionally, intrinsically aged skin is dry and less elastic than more youthful skin. In contrast, extrinsically aged skin is exemplified by deep, coarse wrinkles, mottled hyperpigmentation and a marked loss of elasticity and recoil. The two major environmental influences which induce extrinsic ageing are: (i) chronic exposure to solar ultraviolet (UV) irradiation (termed photoageing) and (ii) smoking. This review discusses the changes associated with the ageing process in the skin, with particular emphasis on the role played by the elastic fibre network in maintaining dermal function. The review concludes with a discussion of a short-term assay for independent assessment of the efficacy of anti-ageing cosmetic products using the elastic fibre component fibrillin-1 as a biomarker of extracellular matrix repair. Résumé Le vieillissement Cutané est le résultat de deux processus biologiques distincts, qui peuvent se produire concurremment : i) le passage de temps, désigné comme vieillissement intrinsèque et ii) les influences environnementales, désignées comme vieillissement extrinsèque. Le vieillissement intrinsèque de la peau est un processus lent provoquant des changements de la structure et détériorant la fonction tissulaire sans facteurs biologiques, chimiques ou physiques supplémentaires. Les caractéristiques cliniques de la peau intrinsèquement âgée sont peu visibles avant la vieillesse où, bien que lisse et impeccable, la surface de la peau apparaît pâle et marquée par des rides notables et des lignes d'expression exagérées. Au niveau fonctionnel, la peau intrinsèquement âgée est sèche et moins d'élastique que la peau plus jeune. Au contraire, la peau extrinsèquement âgée est caractérisée par des rides profondes, grossières, une hyperpigmentation en taches et une perte marquée d'élasticité. Les deux influences environnementales majeures à l'origine du vieillissement extrinsèque sont : i) l'exposition chronique aux ultra-violets (UV) et ii) l'exposition tabagique. Cette revue envisage les changements associés au processus de vieillissement cutané, avec une attention particulière sur le rôle joué par le réseau élastique dans le maintien de la fonction dermique. Cette analyse se termine par une discussion à propos d'un essai d'évaluation de l'efficacité de produits cosmétiques anti-âges utilisant un composant de fibre élastique la fibrillin-1 comme bio marqueur de la réparation de la matrice extracellulaire. [source] How Views about Flow Adaptations of Benthic Stream Invertebrates Changed over the Last CenturyINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4-5 2008Bernhard StatznerArticle first published online: 15 OCT 200 Abstract Throughout the last century, stream ecologists tried to answer the question: how do benthic invertebrates cope with the flows prevailing in streams? Whereas the pioneers frequently sought answers using imagination and speculation in a hefty debate, subsequent research on flow adaptations of stream invertebrates relied increasingly on the transfer of concepts (from fluid mechanics to stream ecology) and technological innovations. Correspondingly, views about flow adaptations of stream invertebrates changed considerably over the last century. However, stream ecologists are still far from understanding how stream invertebrates are adapted to the many different flow conditions they face during their life, because the near-bottom flows they experience are extremely complex and create so diverse constraints that adaptation to all of them is physically impossible. This instance shows how ignorant we are of the physical factors in the environment which ultimately shape the organisms, and how difficult it is to understand the utility of a structure without knowing the requirements for which it is produced Sunder Lal Hora, 1930 (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] History of science , sporesJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2006Lewis B Perry Memorial Lecture 200 Abstract Bacterial endospores were first studied 130 years ago by Cohn in 1876 and independently by Koch in the same year. Although spore dormancy and resistance have been much studied since then, questions still remain concerning the basic mechanisms and the kinetics of heat inactivation in particular. Likewise, the extreme dormancy and longevity of spores was recognized early on and later greatly extended but still evade complete understanding. Evidence has accumulated for the involvement of specific spore components such as calcium, dipicolinic acid, small acid soluble proteins in the core and peptidoglycan in the cortex. Involvement of physical factors too, such as the relative dehydration of the core, maybe in a high-viscosity state or even in a glassy state, has added to appreciation of the multicomponent nature of dormancy and resistance. Spore-former morphology formed the basis for early classification systems of sporeformers from about 1880 and consolidated in the mid-1900s, well prior to the use of modern genetic procedures. With respect to sporulation, groundbreaking sequence studies in the 1950s provided the basis for later elucidation of the genetic control widely relevant to many cell differentiation mechanisms. With respect to the breaking of dormancy (activation and germination), the elucidation of mechanisms began in the 1940s following the observations of Hills at Porton who identified specific amino acid and riboside ,germinants', and laid the basis for the later genetic analyses, the identification of germinant receptor genes and the elucidation of key germination reactions. The nonexponential nature of germination kinetics has thwarted the development of practical Tyndallization-like processing. So inactivation by heat remains the premier method of spore control, the basis of a huge worldwide industry, and still relying on the basic kinetics of inactivation of Clostridium botulinum spores, and the reasoning regarding safety first evolved by Bigelow et al. in 1920 and Esty and Meyer in 1922. ,Newer' processes such as treatment with ionizing radiation (first proposed in 1905) and high hydrostatic pressure (first proposed in 1899) may be introduced if consumer resistance and some remaining technical barriers could be overcome. [source] Strong Static Magnetic Field Stimulates Bone Formation to a Definite Orientation In Vitro and In Vivo,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2002Hiroko Kotani Ph.D. Abstract The induction of bone formation to an intentional orientation is a potentially viable clinical treatment for bone disorders. Among the many chemical and physical factors, a static magnetic field (SMF) of tesla order can regulate the shapes of blood cells and matrix fibers. This study investigated the effects of a strong SMF (8 T) on bone formation in both in vivo and in vitro systems. After 60 h of exposure to the SMF, cultured mouse osteoblastic MC3T3-E1 cells were transformed to rodlike shapes and were orientated in the direction parallel to the magnetic field. Although this strong SMF exposure did not affect cell proliferation, it up-regulated cell differentiation and matrix synthesis as determined by ALP and alizarin red stainings, respectively. The SMF also stimulated ectopic bone formation in and around subcutaneously implanted bone morphogenetic protein (BMP) 2-containing pellets in mice, in which the orientation of bone formation was parallel to the magnetic field. It is concluded that a strong SMF has the potency not only to stimulate bone formation, but also to regulate its orientation in both in vitro and in vivo models. This is the first study to show the regulation of the orientation of adherent cells by a magnetic field. We propose that the combination of a strong SMF and a potent osteogenic agent such as BMP possibly may lead to an effective treatment of bone fractures and defects. [source] Simultaneous analysis of the behavioural phenotype, physical factors, and parenting stress in people with Cornelia de Lange syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 7 2009J. Wulffaert Abstract Background Studies into the phenotype of rare genetic syndromes largely rely on bivariate analysis. The aim of this study was to describe the phenotype of Cornelia de Lange syndrome (CdLS) in depth by examining a large number of variables with varying measurement levels. Virtually the only suitable multivariate technique for this is categorical principal component analysis. The characteristics of the CdLS phenotype measured were also analysed in relation to parenting stress. Method Data for 37 children and adults with CdLS were collected. The type of gene mutation and relevant medical characteristics were measured. Information on adaptive functioning, behavioural problems, the presence of the autistic disorder and parenting stress were obtained through questionnaires and semi-structured interviews with the parents. Chronological age and gender were also included in the analysis. Results All characteristics measured, except gender, were highly interrelated and there was much variability in the CdLS phenotype. Parents perceived more stress when their children were older, were lower functioning, had more behavioural problems, and if the autistic disorder was present. A new perspective was acquired on the relation between the gene mutation type and medical and behavioural characteristics. In contrast with earlier research the severity of medical characteristics did not appear a strong prognostic factor for the level of development. Conclusion Categorical principal component analysis proved particularly valuable for the description of this small group of participants given the large number of variables with different measurement levels. The success of the technique in the present study suggests that a similar approach to the characterisation of other rare genetic syndromes could prove extremely valuable. Given the high variability and interrelatedness of characteristics in CdLS persons, parents should be informed about this differentiated perspective. [source] THE APPLICATION OF ELECTRON SPIN RESONANCE AS A GUIDE TO THE MATURATION AND TYPING OF ORGANIC MATTER IN THE NORTH SEAJOURNAL OF PETROLEUM GEOLOGY, Issue 1 2003R. A. McTavish In early electron spin resonance (ESR) analysis of North Sea wells, maturation of organic matter (OM) was expressed in terms of maximum palaeotemperature (MPT) based on North American calibrations that did not consider the influences of kerogen composition or overpressure. In the North Sea, the MPTs were anomalous in overpressured sequences and relative to other indices of OM maturation such as vitrinite reflectance, so the ESR method was abandoned there in geochemical studies. However, early empirical study of North Sea ESR data indicated that, in relation to functions that linked temperature and pore pressure, some ESR parameters were predictable without reference to MPTs. In order to re-evaluate ESR parameters as indices of OM maturation, the physical factors (temperature and pressure) which affect OM maturation are related in the present paper to the ESR parameters "g" (spectral position) and Ng (spin density) at six well locations in the northern North Sea. A third ESR parameter, W (line width), is not an effective guide to maturation levels due to its complex relationship to the physical factors and kerogen types. However, cross-plots of W versus "g" and Ng appear to be as effective as pyrolysis for kerogen typing. Levels of maturation investigated in the North Sea wells range through the equivalent vitrinite reflectance values of about 0.50,1.50%. The values of "g" and Ng have been differentiated for kerogen type, but undifferentiated values of "g" have also been studied. Regression analysis has shown that there are linear relationships between the ESR parameters "g" and Ng, and the physical factors present-day temperature (To), "effective" temperature (Te), and differential pressure (Pd). Correlation coefficients for both "g" (undifferentiated and differentiated) and Ng (differentiated) relative to the physical factors are high; the highest values are for "g" and Ng relative to Te and Pd (r =,0.950 for "g" differentiated or undifferentiated, r = 0.944,0.976 for Ng differentiated, respectively). However, correlation coefficients were lower for "g" and Ng relative to To. More frequent high correlation coefficients and larger sample populations suggest that "g" (undifferentiated) is a more reliable index of OM maturation than Ng(differentiated). However, the estimation of levels of OM maturation is improved if both indices are used together. The ESR method appears to be effective both for estimating levels of OM maturation and for kerogen typing. It has a number of potential advantages over other geochemical methods: firstly, it is more sensitive for estimating OM maturation than most other methods; secondly, it can be used to analyze organic matter which is as old as Proterozoic; thirdly, it does not destroy the samples analyzed. [source] The effects of 17 August Marmara earthquake on patient admittances to our dermatology departmentJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 3 2002D Bayramgürler Abstract On 17 August 1999 a devastating earthquake with a magnitude of 7.4 on the Richter scale occurred in Marmara region of Turkey and the epicentre of the earthquake was our city. In this study we aimed to determine the influence of a major earthquake on patient admittance's to the outpatient clinic of our dematology department. All the registrations of the outpatient clinic of our dermatology department in a period of 6 months after the earthquake and the same period last year were revised retrospectively and categorized into 15 subgroups. The first 3 months registrations (earthquake group 1) and the second 3 months registrations (earthquake group 2) after the earthquake were compared with those of the same periods in last year, respectively (control group 1 and control group 2). Also the earthquake group 1 was compared with the earthquake group 2. When the results were evaluated, it was seen that the incidence of infections-infestations was significantly higher in the earthquake group 1 when compared with the control group 1. When the earthquake group 2 and the control group 2 were compared with each other regarding the incidences of the skin diseases, no statistically significant difference was found. The incidences of erythematous-squamous skin diseases, pruritus and neurocutaneous dermatoses and eczemas were significantly higher in the earthquake group 2 when compared with the earthquake group 1. On the other hand, the incidences of infections-infestations and dermatoses due to physical factors were significantly lower in the earthquake group 2 when compared with the earthquake group 1. We think that the alteration in the admittance's to outpatient clinic of our dermatology department in the first 3 months after the earthquake is due to the damaged infrastructures and unhygienic life conditions and in the second 3 months is due to psycho-emotional factors related to earthquake. [source] Pattern and process in Norwegian upland grasslands: a functional analysisJOURNAL OF VEGETATION SCIENCE, Issue 1 2002Vigdis Vandvik Lid & Lid (1994) Abstract. Four classes of functional and morphological plant traits , established strategies (the CSR scheme sensu Grime 1979), life-forms (sensu Raunkiaer 1934), morphology, and regenerative strategies , are used as tools for explaining vegetation gradients at summer farms in the mountains of western Norway. These farms are assembly points for free-ranging domestic grazers, and differ floristically and ecologically from the surrounding heath or woodland vegetation. DCA and TWINSPAN are used to relate major gradients in a floristic data set from 12 summer farms to two sets of explanatory variables: (1) environmental variables representing physical factors, plot position, soils, and land use, and (2) the 4 classification schemes. The main floristic gradient parallels a spatial gradient from the centres of the farms to the surrounding vegetation. A functional interpretation based on the concurrent use of the 2 sets of explanatory variables suggests that the gradient is one of decreasing disturbance and increasing environmental stress caused by decreasing grazing and manure effects away from farms. Partial CCA is used to investigate the relationships between the 4 functional/morphological plant trait classes. The 4 classification schemes are partially redundant, and do not represent different trends of specialization within the landscape. There is no strong evidence for decoupling of the traits of the vegetative and regenerative phases within the data. The combination of general process-based theories and specific plant attribute responses enhances the generality and interpretability of the study. [source] | |||||||||||||||||||||||||||||||