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Geographical Differences (geographical + difference)
Selected AbstractsGeographical difference in antimicrobial resistance pattern of Helicobacter pylori clinical isolates from Indian patients: Multicentric studyJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 12 2003SP THYAGARAJAN Abstract Aim:, To assess the pattern of antimicrobial resistance of Helicobacter pylori isolates from peptic ulcer disease patients of Chandigarh, Delhi, Lucknow, Hyderabad and Chennai in India, and to recommend an updated anti- H. pylori treatment regimen to be used in these areas. Methods:, Two hundred and fifty-nine H. pylori isolates from patients with peptic ulcer disease reporting for clinical management to the Post Graduate Institute of Medical Education and Research, Chandigarh; All India Institute of Medical Sciences, New Delhi; Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow; Deccan College of Medical Sciences and Allied Hospitals, Hyderabad; and hospitals in Chennai in collaboration with the Dr ALM Post Graduate Institute of Basic Medical Sciences were analyzed for their levels of antibiotic susceptibility to metronidazole, clarithromycin, amoxycillin, ciprofloxacin and tetracycline. The Epsilometer test (E-test), a quantitative disc diffusion antibiotic susceptibility testing method, was adopted in all the centers. The pattern of single and multiple resistance at the respective centers and at the national level were analyzed. Results:, Overall H. pylori resistance rate was 77.9% to metronidazole, 44.7% to clarithromycin and 32.8% to amoxycillin. Multiple resistance was seen in 112/259 isolates (43.2%) and these were two/three and four drug resistance pattern to metronidazole, clarithromycin, amoxycillin observed (13.2, 32 and 2.56%, respectively). Metronidazole resistance was high in Lucknow, Chennai and Hyderabad (68, 88.2 and 100%, respectively) and moderate in Delhi (37.5%) and Chandigarh (38.2%). Ciprofloxacin and tetracycline resistance was the least, ranging from 1.0 to 4%. Conclusion:, In the Indian population, the prevalence of resistance of H. pylori is very high to metronidazole, moderate to clarithromycin and amoxycillin and low to ciprofloxacin and tetracycline. The rate of resistance was higher in southern India than in northern India. The E-test emerges as a reliable quantitative antibiotic susceptibility test. A change in antibiotic policy to provide scope for rotation of antibiotics in the treatment of H. pylori in India is a public health emergency. [source] Geographical difference in Parkinson's disease prevalence within West Scotland,MOVEMENT DISORDERS, Issue 3 2009Edward J. Newman MRCP Abstract The wide range in reported prevalence of Parkinson's disease (PD) in the United Kingdom (between 108 and 164 per 100,000) is usually attributed to differences in study methodology. We report prevalence of PD in four geographic areas within West Scotland, which was calculated using the same methodology, from prescription database searches within primary care, combined with full case record review. Crude prevalence was 119.2 per 100,000 (95% CI 109.7,128.6) and age-adjusted prevalence was 129.5 (95% CI 119.6,139.4) in 92 General Practices covering a population of 511,927. Prevalence was significantly lower in South Glasgow (men 98.3, CI 78.7,117.9; women 83.9, CI 65.6,102.2) than South Lanarkshire (men 202.7, CI 175.0,230.4; women 151.1, CI 127.7,174.5), age-adjusted rates, both P < 0.001. Factors associated with higher prevalence of PD, such as lower cigarette smoking rates, higher education level, and rural living, were higher in South Lanarkshire than South Glasgow, but the magnitude of the difference was greater than expected considering studies describing relative risk for these factors. Access to services, and specialist clinic attendance were both higher for South Glasgow, which may influence diagnostic accuracy, time to diagnosis, and time to initiating antiparkinson therapy. Explorationof these factors is justified to explain further such wide variation in PD prevalence. © 2008 Movement Disorder Society [source] Geographical differences in seasonal clutch size variation in multi-brooded bird speciesIBIS, Issue 4 2002André A. Dhondt The seasonal pattern of clutch size variation in birds varies among species. In single-brooded bird species clutch sizes decline continuously with date from an early season maximum. In resident multi-brooded species, clutch sizes first increase to a mid-season maximum and then decrease again. Limited data for multi-brooded migratory birds suggest that clutches in these species also show a continuous decline throughout the season, but it remains to be resolved whether this applies generally and whether migration adds a constraint to the system. We here report on a study of the Eastern Bluebird Sialia sialis conducted using data collected by volunteers across most of its range. In the southern part of its range, where Eastern Bluebirds are largely year-round residents, clutches initially increase, reach a mid-season maximum and gradually decline later in the season. In the northern part of the range, where the majority of Eastern Bluebirds are migratory, clutch sizes decline continuously throughout the season. To determine whether seasonal changes in the clutch size of multi-brooded species are determined by migratory behaviour of the population we compared our results with published data on the Dunnock Prunella modularis and conclude that in multi-brooded species migratory behaviour is not a sufficient condition for a continuous seasonal decline in clutch size, but it could be a necessary one. We propose two mechanisms for the pattern observed among multi-brooded migrants: (i) a time or energy cost of migration, and (ii) a more abrupt increase in seasonal resources in spring at more northerly latitudes. [source] Geographical differences within Finland in the frequency of HLA-DQ genotypes associated with Type 1 diabetes susceptibilityINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 4 2000J. Ilonen Geographical variations in the HLA-DQ genotypes associated with risk for type 1 diabetes were evaluated in Finland. Samples of 280 diabetic children diagnosed in Turku (south-west of the country) and 405 in Oulu (north of the country) were studied as well as a series of 14 096 and 10 016 newborns collected from the same hospitals. There were no major differences in the risk or protection conferred by various HLA-DQB1 genotypes between south-western and northern parts of the country when genotypes of children with type 1 diabetes from these two centres were compared with those of newborns, representing the background populations. However, the distribution of various genotypes was different, both in diabetic children and in newborns, when compared between the two regions (P < 0.0001, ,2 test). These differences reflected the allele frequencies in newborn cohorts in which HLA-DQB1*02 and DQB1*0301 were found more often in Turku and DQB1*0302 more often in Oulu (P < 0.0001 for all differences). Similar types of differences were detected when children who were diagnosed as having diabetes during the national ,Childhood Diabetes in Finland' (DiMe) study between the years 1986,1989 were compared according to their residence. The observed differences in genotype and allele frequencies demonstrate the heterogeneity for HLA alleles even in a population that is generally regarded as highly homogeneous. These differences also affect the sensitivity and efficiency of the screening programme used for identifying infants with genetic susceptibility to IDDM in the ongoing Finnish Diabetes Prediction and Prevention Study. [source] Trophic diversity of the otter (Lutra lutra L.) in temperate and Mediterranean freshwater habitatsJOURNAL OF BIOGEOGRAPHY, Issue 5 2003Miguel Clavero Abstract Aim To analyse the geographical patterns in the composition and diversity of otter's (Lutra lutra L.) diet and their relationship with climatic characteristics. Location European freshwater habitats under Mediterranean and temperate climatic regimes. Methods Thirty-seven otter diet studies were reviewed, twenty-one from temperate and sixteen from Mediterranean areas. All studies were based on spraint analysis and their results expressed as relative frequency of occurrence of seven main prey categories. Principal Component Analysis was performed to extract the main gradients of diet composition. Pearson's correlation and t -tests were used to assess the relationship between diet characteristics (composition, diversity and taxonomic richness) and geographical and climatic variables. Results A clear latitudinal gradient in diet composition was observed. Otter diet was more diverse and featured more prey classes in southern localities, while the species was more piscivorous towards the north, where it predated upon a higher number of fish families. This pattern was similar when temperate and Mediterranean localities of Europe were compared. Mediterranean otters behaved as more generalist predators than temperate ones, relying less on fish, and more on aquatic invertebrates and reptiles. Main conclusions Geographical differences in otter feeding ecology in Europe seem to be related with the two contrasted climatic conditions affecting prey populations. The otter can act as a highly specialized piscivorous predator in temperate freshwater ecosystems, which do not suffer a dry season and have a comparatively stable water regime compared to Mediterranean ones. However, the unpredictable prey availability in Mediterranean areas, affected by strong spatial and temporal water shortages, favours a diversification of the otter's diet. [source] GEOGRAPHICAL VARIATION OF THE PARASITE, PHYLLOBOTHRIUM DELPHINI (CESTODA), IN BALL'S PORPOISE, PHOCOENOIDES DALLI, IN THE NORTHERN NORTH PACIFIC, BERING SEA, AND SEA OF OKHOTSKMARINE MAMMAL SCIENCE, Issue 2 2001William A. Walker Abstract Prevalence of the larval cestode, Phyllobothrium delphini, was estimated from 2,445 Dall's porpoise, Phocoenoides dalli, from the incidental take of the Japanese high seas salmon drift-net fishery in the northwestern North Pacific Ocean, Bering Sea, and a local hand harpoon fishery in the southern Sea of Okhotsk. Prevalence of P. delphini was 22.7% in the northwestern North Pacific Ocean and 1.4% in the Bering Sea. This parasite was not found in the southern Sea of Okhotsk. Geographical differences in the prevalence of P. delphini may be due, at least in part, to regional differences in abundance of elasmobranchs known to feed on marine mammals and suspected as hosts of the parasite. Estimated intensity of infection of individual porpoises by P. delphini was low (estimated mean intensity of 3.5 plerocercoids per animal). This is a low intensity of infection compared to other species of small cetaceans studied and may be due to both differences in regional abundance of elasmobranchs and the comparatively short life span of P. dalli. [source] Geographical differences in physiques of male youth of age 18,20 years in ChinaAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2006Shang Lei Three national surveys on the physical status of 18-, 19-, and 20-year-old male candidates for military service were carried out in six geographic regions of China in 1955, 1974, and 2001. Data from these surveys for 72,000 individuals were compared by region, by time, and by age, and estimates of incremental changes by decade were made. Overall, at all time points, males in the north and northeast areas were larger and heavier than males in the southwest. Similarly, the proportion of males in the north and northeast who were overweight was greater than in the other areas. The proportion classified as "thin" was highest in the south, southwest, and northwest, reaching 42.6% in the northwest. When urban and rural areas were compared, the mean value of every measure in every region was higher for urban youth, with all but two comparisons reaching significance (P<0.05). Differences of chest circumference among age groups were significant, as were differences in height, weight, and body mass index for 18-year-olds compared to 20-year-olds. Overall, height increments per decade were greatest for males in the southwest (average of age groups 1.79 cm, 1974 to 2001) and least in the northeast (1.08), indicating some tendency toward convergence over time. Weight increments per decade over the same time were greatest in north China (1.37 kg) and least in the northwest region (0.58 kg). Am. J. Hum. Biol. 18:141,148, 2006. © 2005 Wiley-Liss, Inc. [source] Assessing risk indicators for dental caries in the primary dentitionCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 6 2001Jackie Vanobbergen Abstract , The aim of the present study was to assess indicators shown to be associated with the prevalence of caries in the primary dentition of 7-year-old Flemish schoolchildren. Cross-sectional first year data of the longitudinal Signal-Tandmobiel® survey were analysed (n=4468). Gender, age, oral hygiene habits, use of fluorides, dietary habits, geographical factors and parental modelling were the considered predictors. From the multiple logistic regression analysis, including schools as a random effect, and after adjusting for the confounding variables,educational system and province (stratification variables), gender and age,it became clear that the following risk indicators remained significant (at 5% level) for the presence of caries: frequency of toothbrushing (P=0.05) with an OR 1.24 for brushing less than once a day, age at start of brushing (P<0.001) with an OR=1.22 for a delay of 1 year, regular use of fluoride supplements (P<0.001) with an OR=1.54 for no use, daily use of sugar-containing drinks between meals (P<0.001) with an OR=1.38, and number of between-meals snacks (P=0.012) with an OR=1.22 for using more than 2 between-meal snacks. There was a significant difference (P<0.05) in caries experience determined by the geographical spread, with an explicit trend of caries declining from the east to the west. In a model with an ordinal response outcome, the daily use of sugar-containing drinks between meals had a more pronounced effect when caries levels were high. From this study it became obvious that, in Flemish children, an early start of brushing and a brushing frequency of at least once a day need to be encouraged, while the use of sugar-containing drinks and snacks between meals needs to be restricted to a maximum of 2 per day. Geographical differences need to be investigated in more detail. [source] Molecular phylogeny of Turkish Trachurus species (Perciformes: Carangidae) inferred from mitochondrial DNA analysesJOURNAL OF FISH BIOLOGY, Issue 5 2008Y. Bektas Genetic variation among three species of Trachurus (T. trachurus, T. mediterraneus and T. picturatus) from Turkey was investigated by phylogenetic analysis of the entire mtDNA control region (CR) (862 bp, n = 182) and partial cytochrome (cyt) b (239 bp, n = 174) sequences. Individuals were collected at nine stations in four geographic locations: North-eastern Mediterranean Sea, Aegean Sea, Sea of Marmara and Black Sea. Polymerase chain reaction-direct sequencing of the CR and the partial cyt b genes produced 28 and 131 distinct haplotypes, respectively. Maximum likelihood, neighbour-joining and maximum parsimony methods produced similar tree topologies. The results of both CR and cyt b sequence analyses revealed the existence of several species-specific nucleotide sites that can be used to discriminate between the three species. Genetic distances indicated that T. mediterraneus and T. picturatus are more closely related to each other than either is to T. trachurus. Inter-nucleotide and intra-nucleotide diversities of T. picturatus were larger than those of T. mediterraneus and T. trachurus. There was no evidence of a geographical difference in haplotype frequencies of these two mtDNA regions to be clustered. [source] Urothelial progenitor cells: regional differences in the rat bladderCELL PROLIFERATION, Issue 2 2007M. M. Nguyen As yet there is no marker nor methodology to specifically isolate urothelial stem cells, and thus demonstrate multi-potential differentiation and self-renewal. Here, our goal was to evaluate the distribution of progenitor cells that carry two general major attributes of stem cells: clonogenicity and proliferative capacity. Materials and methods: The bladders of Fisher rats were divided into caudal and cephalic segments and primary cultures were established from the harvested urothelial cells. Results: We found that colony-forming efficiency was almost 2-fold higher for cells from the caudal bladder compared to the cephalic bladder. Doubling time was significantly faster for cells harvested from the caudal bladder at initial plating. This suggested that the caudal bladder harbours a higher density of urothelial progenitor cells. With passage to p4, the differences between the upper and lower bladder were lost, suggesting selection of proliferative cells with serial passage. Based on Ki-67 staining, there was no geographical difference in cell proliferation under normal homeostatic in vivo conditions. Conclusions: These results demonstrate geographical sequestration of urothelial progenitor cells to the area of the bladder that encompasses the bladder neck and trigone, which may be a factor in pathological disparities between the trigone and remaining bladder. [source] Geographic Pathology of Helicobacter pylori GastritisHELICOBACTER, Issue 2 2005Yi Liu ABSTRACT Background and aim.,Helicobacter pylori is etiologically associated with gastritis and gastric cancer. There are significant geographical differences between the clinical manifestation of H. pylori infections. The aim of this study was to compare gastric mucosal histology in relation to age among H. pylori -infected patients from different geographical areas using the same grading system. The prevalence of atrophy and intestinal metaplasia were also compared with the respective gastric cancer incidence in the different countries. Methods., A total of 1906 patients infected with H. pylori from seven countries were evaluated. Entry criteria included H. pylori positive cases with antral and corpus biopsies between the ages of 18 and 75 years. The minimum number of cases required from a country was 100. Hematoxylin-eosin stained biopsies from antrum and corpus were scored semiquantitatively using the parameters suggested by the Sydney Classification System. Statistical evaluation was performed using Krusakal-Wallis test and Spearman's rank correlation test. Results., The severity of gastric atrophy varied among the different groups with the highest scores being present in Japan. The lowest scores were found in four European countries and in Thailand. The scores for intestinal metaplasia were low in general except for Xi-an, Japan, and Shanghai. For all the countries, the presence of atrophy in the antrum correlated well (r = 0.891) with the incidence of gastric cancer. Conclusion., Using a standardized grading system in a large study of H. pylori -related geographic pathology, we found major differences in the overall prevalence and severity of H. pylori gastritis in relation to age. These differences mirrored the respective incidences of gastric cancer in those geographical areas. [source] Spatial and temporal variation of fire regimes in a mixed conifer forest landscape, Southern Cascades, California, USAJOURNAL OF BIOGEOGRAPHY, Issue 8 2001R. Matthew Beaty Aim In this study, we evaluated the fire-forest mosaic of a mixed conifer forest landscape by testing the hypothesis that pre-fire suppression fire regime parameters vary with species composition (tree species), and environment (i.e. slope aspect, slope position, elevation). Location Our study was conducted in the 1587 ha Cub Creek Research Natural Area (CCRNA), Lassen National Forest, CA, USA. Methods We quantified the return interval, seasonal occurrence, size, rotation period, and severity of fires using dendroecology. Results Slope aspect, potential soil moisture, forest composition, and fire regime parameters in our study area co-vary. Median composite and point fire return intervals (FRI) were longest on higher, cooler, more mesic, north-facing (NF) slopes covered with white fir (Abies concolor), Douglas fir (Pseudotsuga menziesii),white fir, and red fir (A. magnifica),white fir forests, shortest on the dry, south-facing (SF) slopes covered with ponderosa pine (Pinus ponderosa),white fir forests and intermediate on west-facing slopes dominated by white fir,sugar pine (P. lambertiana),incense cedar (Libocedrus decurrens) forests. The spatial pattern for length of fire rotation (FR) was the same as that for FRI. Fires in CCRNA mixed conifer forests occurred mainly (90%) in the dormant season. Size of burns in CCRNA mixed conifer forests were generally small (mean=106 ha), however, during certain drought years widespread fires burned across fuel breaks and spread throughout the watershed. Fire severity was mainly high on upper slopes, low on lower slopes and moderate and low severity on middle slopes. Patterns of fire severity also varied with slope aspect. Fire frequency decreased dramatically in CCRNA after 1905. Conclusions In CCRNA, fire regime parameters [e.g. FRI, fire extent, FR, fire severity] varied widely with species composition, slope aspect and slope position. There was also temporal variation in fire extent with the most widespread fires occurring during drought years. The important contributions of topography and climate to variation in the fire regime indicates that exogenous factors play a key role in shaping the fire-forest structure mosaic and that the fire-forest structure mosaic is more variable, less predictable and less stable than previously thought. Finally, some characteristics of the fire regime (i.e. fire severity, season of burn) in CCRNA are different than those described for other mixed conifer forests and this suggests that there are geographical differences in mixed conifer fire regimes along the Pacific slope. [source] Secrets in the eyes of Black Oystercatchers: a new sexing techniqueJOURNAL OF FIELD ORNITHOLOGY, Issue 2 2008Brian M. Guzzetti ABSTRACT Sexing oystercatchers in the field is difficult because males and females have identical plumage and are similar in size. Although Black Oystercatchers (Haematopus bachmani) are sexually dimorphic, using morphology to determine sex requires either capturing both pair members for comparison or using discriminant analyses to assign sex probabilistically based on morphometric traits. All adult Black Oystercatchers have bright yellow eyes, but some of them have dark specks, or eye flecks, in their irides. We hypothesized that this easily observable trait was sex-linked and could be used as a novel diagnostic tool for identifying sex. To test this, we compared data for oystercatchers from genetic molecular markers (CHD-W/CHD-Z and HINT-W/HINT-Z), morphometric analyses, and eye-fleck category (full eye flecks, slight eye flecks, and no eye flecks). Compared to molecular markers, we found that discriminant analyses based on morphological characteristics yielded variable results that were confounded by geographical differences in morphology. However, we found that eye flecks were sex-linked. Using an eye-fleck model where all females have full eye flecks and males have either slight eye flecks or no eye flecks, we correctly assigned the sex of 117 of 125 (94%) oystercatchers. Using discriminant analysis based on morphological characteristics, we correctly assigned the sex of 105 of 119 (88%) birds. Using the eye-fleck technique for sexing Black Oystercatchers may be preferable for some investigators because it is as accurate as discriminant analysis based on morphology and does not require capturing the birds. SINOPSIS El sexado de ostreros en el campo es sumamente difícil dado el caso de que tanto hembras como machos tienen plumaje idéntico y son similares en tamaño. Aunque los ostreros negros (Haematopus bachmani) son sexualmente dimórficos, el utilizar morfometría para determinar su sexo requiere capturar a ambos miembros de la pareja para compararlos, utilizando una análisis discriminativo a modo de asignar un sexo por probabilidad, basado en características morfométricas. Todos los adultos del ostrero negro tienen ojos amarillos y brillantes, pero algunos tienen manchas oscuras en el iris. Tomamos como hipótesis que estas peculiaridades observables estaban ligada al sexo, y que podían ser utilizadas como una herramienta novel de diagnóstico para identificar el sexo en dichas aves. Para poner a pruebas lo mencionado, comparamos datos de ostreros donde se utilizaron marcadores genéticos moleculares (CHD-W/CHD-Z y HINT-W/HINT-Z), análisis morfométrico, y categorías en las manchas en los ojos (manchas marcadas en los ojos, algunas manchitas en los ojos, sin manchas en los ojos). Comparado a marcadores moleculares, encontramos que el análisis discriminativo basado en características morfológicas ofrecía resultados variables asociados a diferencias morfológicas geográficas. Sin embargo, encontramos que las manchas en los ojos estaban ligadas al sexo. Utilizando un modelo de manchas en los ojos, en donde clasificamos como hembras aquellos individuos con manchas pronunciadas en los ojos y a machos con muy pocas manchitas o sin manchitas, le pudimos asignar correctamente el sexo a 117 de 125 (94%) individuos. Utilizando una análisis discriminativo basado en características morfológicas, le asignamos el sexo correctamente a 105 de 119 (88%) individuos. El utilizar la técnica de manchas en los ojos para el sexado de ostreros negros pudiera ser preferible para algunos investigadores porque es más exacto que el análisis discriminativo basado en morfología y porque no requiere que se tenga que capturar a las aves. [source] Fish condition analysis by a weighted least squares procedure: testing geographical differences of an endangered Iberian cyprinodontidJOURNAL OF FISH BIOLOGY, Issue 6 2001A. Vila-Gispert A weighted procedure for analysing fish condition, when conventional ANCOVA assumptions cannot be assumed because the coefficients of regression and residual variances were not equal among groups, proved adequate for most data sets. Data for an Iberian cyprinodontid fish were used to demonstrate the proposed method. [source] Sensitivity of different taxonomic levels of soil Gamasina to land use and anthropogenic disturbancesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2010José Camilo Bedano 1The effect of taxonomic level on the sensitivity of bioindicators has been widely investigated in aquatic ecosystems and, to a lesser extent, in terrestrial ecosystems. However, no studies have been conducted on the sensitivity of the different taxonomic levels of soil mites, especially Gamasina, to human activities. 2The present study aimed to assess the sensitivity of different taxonomic levels of soil Gamasina mites to anthropogenic disturbances in Europe and Argentina. We arranged the data from previous projects in a hierarchical system and conducted a study to identify the critical taxonomical levels that had the highest discriminative potential between sites (Europe and Argentina) or management types (forests, grasslands, fallows, succession, recultivation and agricultural sites). 3For the Gamasina community, geographical location was by far more important than the influence of any land use type. The analysis including only the European sites demonstrated that communities belonging to sites subjected to different land uses were also significantly different. 4The species data set provided a clearer separation of sites according to both the geographical and the land-use gradients than the genus and family data sets. The genus and, to a lesser extent, the family approach may be sufficient to elucidate the influence of great geographical differences and also of certain land uses (e.g. grasslands from the forests and arable sites). 5Species presence/absence data provided valuable information in our analyses, although the use of quantitative data yielded a clearer separation of sites. [source] Why Do People from Southern Italy Seek Jobs in the Public Sector?LABOUR, Issue 1 2003Laura Pagani This paper analyses the choice open to a worker seeking a job in the public and private sectors of the labour market. The private sector is identified by a steeper wage profile and by lower job security than the public sector. The reservation wage for the two sectors is calculated in the first part of the paper. The results reveal that the reservation wage for the public sector is higher than that for the private sector. The effect of career prospects, job riskiness and labour demand on optimal time allocation between the search in the two sectors is then analysed. Finally, an empirical analysis is made in order to study Italian workers' search strategies. It highlights relevant geographical differences which can be interpreted through the theoretical results obtained in the paper. [source] Differences in pollinator faunas may generate geographic differences in floral morphology and integration in Narcissus papyraceus (Amaryllidaceae)OIKOS, Issue 11 2007Rocío Pérez-Barrales Pollinators may generate selective pressures that affect covariation patterns of multiple traits as well as the mean values of single floral morphological traits. Berg predicted that flowers pollinated by animals whose morphology closely matches the flower's shape will be phenotypically more integrated (tighter correlation of flower traits) than will flowers pollinated by animals not closely fitting the floral morphology. We tested this hypothesis by comparing, in the Strait of Gibraltar region (south Spain, northern Morocco), populations of Narcissus papyraceus that have geographical differences in pollinator faunas. Long-tongued, nectar-feeding moths dominate the pollinator faunas of those populations close to the Strait of Gibraltar, whereas short-tongued, pollen-feeding syrphid flies dominate in peripheral populations farther from the Strait. Populations pollinated by moths and flies differed in the mean values of several floral traits, consistent with the evolution of regional pollination ecotypes. Populations pollinated by moths showed stronger intercorrelation (floral integration) than populations pollinated by hoverflies. Moth-pollinated populations also showed less variation in flower traits than vegetative traits, and this difference was stronger than in fly-pollinated populations. Thus, the pattern of differences in the phenotypic architecture of the Narcissus flowers is consistent with the hypothesis that populations have responded to different selective pressures generated by different pollinators. These data also supported most of the specific predictions of Berg's hypotheses about integration and modularity. [source] Role of wild plant foods among late Holocene hunter-gatherers from Central and North Patagonia (South America): An approach from dental evidenceAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2007Valeria Bernal Abstract This study evaluates the role of plant foods in the subsistence of hunter-gatherers that inhabited the Central East, Northwest, and Northeast Patagonia (Argentina) during the late Holocene (ca. 3,000,500 years BP). The goal of the present study is to assess the temporal variation of dental caries ratio and wear rate in skeletal samples to ascertain if the biological information supports the dietary shift toward greater consumption of wild plant foods around 1,500 years BP, suggested by other types of evidence. The authors registered caries, antemortem and postmortem tooth loss, and tooth wear from eight samples belonging to hunter-gatherers from Patagonia for which chronological sequences from early late Holocene (ca. 3,000,1,500 years BP) up to final late Holocene (ca. 1,500,500 years BP) are available. The results indicate that caries percentages in Patagonian samples fall within the range established for hunter-gatherers but there are significant geographical differences. In addition, caries ratio does not change significantly through time, so the amount of carbohydrates consumed seems to have remained fairly constant since 3,000 years BP. In contrast, there is a marked temporal trend toward the reduction of wear rates in the three areas, suggesting a faster rate in early late Holocene than in final late Holocene. These results would reflect a change to less hard and/or abrasive diets in the final late Holocene, probably owing to differences in food processing methods employed. Am J Phys Anthropol, 2007. © 2007 Wiley-Liss, Inc. [source] There are High Levels of Functional and Genetic Diversity in Oxyrrhis marinaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2005CHRIS D. LOWE Abstract. Oxyrrhis marina, a widely distributed marine protist, is used to model heterotrophic flagellate responses in microbial food webs. Although clonal variability occurs in protists, assessments of intraspecific diversity are rare; such assessments are critical, particularly where species are used as models in ecological studies. To address the extent of intraspecific variation within O. marina, we assessed diversity among 11 strains using 5.8S rDNA and ITS sequences. The 5.8S rDNA and ITS regions revealed high divergence between strains: 63.1% between the most diverse. To compare O. marina diversity relative to other alveolates, 18S rDNA sequences for five strains were analysed with sequences from representatives of the major alveolate groups. 18S rDNA also revealed high divergence in O. marina. Additionally, consistent with phylogenies based on protein coding genes, maximum likelihood analysis indicated that O. marina was monophyletic and ancestral to the dinoflagellates. To assess ecophysiological differences, growth rates of seven O. marina strains were measured at 10 salinities (10,55,). Two salinity responses occurred: one group achieved highest growth rates at high salinities; the other grew best at low salinities. There was no clear correlation between molecular, ecophysiological, or geographical differences. However, salinity tolerance was associated with habitat type: intertidal strains grew best at high salinities; open-water strains grew best at low salinities. These data indicate the need to examine many strains of a species in both phylogenetic and ecological studies, especially where key-species are used to model ecological processes. [source] Contributions of ethnobiology to the conservation of tropical rivers and streamsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2008R.A.M. Silvano Abstract 1.This study aimed to link basic ethnobiological research on local ecological knowledge (LEK) to the conservation of Brazilian streams, based on two case studies: original data on LEK of fishermen about freshwater fish in the Negro River, Amazon, and previously published data about LEK of farmers on the ecological relationship between forest and streams in the Macabuzinho catchment, Atlantic Forest. 2.Information was obtained from fishermen through interviews using standard questionnaires containing open-ended questions. Informants for interview were selected either following some defined criteria or applying the ,snowball' method. 3.Fishermen's LEK about the diets and habitats of 14 fish species in the Negro River provided new biological information on plant species that are eaten by fish, in addition to confirming some ecological patterns from the biological literature, such as dependence of fish on forests as food sources. 4.In the Atlantic Forest, a comparison between farmers' LEK and a rapid stream assessment in the farmers' properties indicated that farmers tended to overestimate the ecological integrity of their streams. Farmers recognized at least 11 forest attributes that correspond to the scientific concept of ecosystem services. Such information may be useful to promote or enhance dialogue among farmers, scientists and managers. 5.These results may contribute to the devising of ecosystem management measures in the Negro River, aimed to conserve both rivers and their associated floodplain forests, involving local fishermen. In the Atlantic Forest, we proposed some initiatives, such as to allow direct economic use of their forests to conciliate conflicting perceptions of farmers about ecological benefits versus economic losses from reforestation. Despite their cultural, environmental and geographical differences, the two study cases are complementary and cost-effective and promising approaches to including LEK in the design of ecological research. Copyright © 2007 John Wiley & Sons, Ltd. [source] Identifying sources of variation in reproductive and life-history traits among five populations of a Chinese lizard (Takydromus septentrionalis, Lacertidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2005WEI-GUO DU Research on life-history traits of squamate reptiles has focused on North American species, while Asian taxa have been virtually ignored. In order to understand general patterns in reptile life histories, we need a broader data base. Our study on the slender-bodied lacertid lizard Takydromus septentrionalis provides the first detailed information on factors responsible for intraspecific variation in reproductive output and life history in a Chinese reptile. Clutches of recently collected lizards from five widely separated localities in China revealed major divergences in female body size at maturation, mean adult female body size, body condition after oviposition, size-adjusted fecundity, relative clutch mass, and mass and shape of eggs. Most of these geographical differences persisted when the same groups of females were maintained in identical conditions in captivity. Additionally, reproductive frequency during maintenance under laboratory conditions differed according to the animals' place of origin. Thus, the extensive geographical variation in reproductive and life-history traits that occurs within T. septentrionalis is exhibited even in long-term captives, suggesting that proximate factors that vary among localities (local conditions of weather and food supply) are less important determinants of life-history variation than are intrinsic (presumably genetic) influences. The maternal abdominal volume available to hold the clutch may be one such factor, based on low levels of variation in Relative Clutch Mass among populations, and geographical variation in the position of trade-off lines linking offspring size to fecundity. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 443,453. [source] Travel-associated non-typhoidal salmonellosis: geographical and seasonal differences and serotype distributionCLINICAL MICROBIOLOGY AND INFECTION, Issue 2 2005K. Ekdahl Abstract The Swedish database on notifiable communicable diseases was used to identify 24 803 cases of travel-associated non-typhoidal salmonellosis from the period 1997,2003. Serotype data were available for 24 358 (98.2%) of these cases, which were compared with a data set from the same period of 16 255 randomly selected Swedish residents with a history of recent overnight travel outside Sweden. The highest risk of disease was seen in travellers returning from East Africa (471/100 000 travellers; 95% CI 294,755), or the Indian subcontinent (474/100 000; 95% CI 330,681). Children aged 0,6 years were at higher risk than travellers of other ages (OR 2.4; 95% CI 2.1,2.8). Some distinct seasonal patterns could be distinguished, with highest (adjusted) risk in December in East Asia, and in August in Europe. Marked geographical differences in serotype distribution were noted. Salmonella Enteritidis was especially dominant in Europe, but was much less common in Africa, Asia and America, where the variety of circulating serotypes was greater. Overall, the two data sets provided important information on travel risks which are also likely to apply to travellers from other western countries. [source] | |||||||||||||||||||||||||