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1.
Osler disease is an autosomal dominant disorder of the fibrovascular tissue characterized by arteriovenous malformations with multi‐systemic haemorrhages. Recurrent epistaxis is the predominant symptom in more than 90% of patients. Recent studies showed circadian and seasonal patterns in the onset of nosebleeds, similar to acute cardiovascular events, such as myocardial infarction and stroke. The aim of this study was to determine whether such patterns would also apply to the onset of epistaxis in patients with Osler disease. In all, 110 patients with Osler disease who were under treatment for recurrent epistaxis at the University Hospital of Mannheim were requested to complete a questionnaire addressing the intensity and frequency of epistaxis according to the classification of Bergler et al., as well as circadian and circannual rhythmicity in the occurrence of epistaxis according to visual analogue scales (VAS). More than half of the patients claimed to experience daily to weekly episodes of recurrent epistaxis. The occurrence of epistaxis showed a biphasic 24 h pattern, with a primary peak in the morning (05∶00–8∶00 h) and smaller secondary peaks in the evening (17∶00–20∶00 h and 21∶00–00∶00 h). No significant seasonal variation was found in the onset of epistaxis. However, a slight tendency, with a peak in winter months, was observed. Similar to other chronobiological studies on nosebleeds, this study showed that the 24 h pattern and seasonal tendency in the onset of epistaxis even applied to patients with Osler disease. Further investigations are necessary to determine the pathological mechanism underlying this phenomenon.  相似文献   

2.
The phenotypic plasticity of plants has been explored as a function of either ontogeny (apparent plasticity) or environment (adaptive plasticity), although few studies have analyzed these factors together. In the present study, we take advantage of the dispersal of Aechmea mertensii bromeliads by Camponotus femoratus or Pachycondyla goeldii ants in shaded and sunny environments, respectively, to quantify ontogenetic changes in morphological, foliar, and functional traits, and to analyze ontogenetic and ant species effects on 14 traits. Most of the morphological (plant height, number of leaves), foliar (leaf thickness, leaf mass area, total water content, trichome density), and functional (leaf δ13C) traits differed as a function of ontogeny. Conversely, only leaf δ15N showed an adaptive phenotypic plasticity. On the other hand, plant width, tank width, longest leaf length, stomatal density, and leaf C concentration showed an adaptation to local environment with ontogeny. The exception was leaf N concentration, which showed no trend at all. Aechmea mertensii did not show an abrupt morphological modification such as in heteroblastic bromeliads, although it was characterized by strong, size‐related functional modifications for CO2 acquisition. The adaptive phenotypic variation found between the two ant species indicates the spatially conditioned plasticity of A. mertensii in the context of insect‐assisted dispersal. However, ant‐mediated effects on phenotypic plasticity in A. mertensii are not obvious because ant species and light environment are confounding variables. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 299–312.  相似文献   

3.
The administration‐time‐dependent aspects of the drug interaction between lithium and morphine‐induced analgesia were studied using the mouse hot‐plate test at six different times of day, each scheduled at 4 h intervals. Lithium treatment alone, in doses of 1 to 10 mmol/kg administered intraperitoneally (i.p.) did not significantly alter test latencies compared to the corresponding clock‐time in saline‐injected controls. Basal pain sensitivity and morphine‐induced antinociceptive activity displayed significant circadian rhythms as assessed by the hot‐plate response latencies, with higher values occurring during the nocturnal activity than during the daytime rest span. Acute administration of lithium, in a dose of 3 mmol/kg, 30 min prior to morphine dosing did not influence morphine‐induced analgesia compared to all the clock‐time test‐matched morphine groups, except the 9 HALO (Hours After Lights On) one. There was a prominent potentiation of the morphine‐induced antinociception at this biological time during combined drug treatment. The latter finding demonstrates that administration‐time‐dependent differences in drug‐drug interactions need to be considered in both experimental designs and clinical settings.  相似文献   

4.
Parasites often manipulate host immunity for their own benefit, either by exacerbating or suppressing the immune response and this may directly affect the expression of parasite virulence. However, genetic variation in immunodepression, which is a prerequisite to its evolution, and the relationship between immunodepression and virulence, have rarely been studied. Here, we investigated the variation among sibships of the acanthocephalan parasite, Pomphorhynchus laevis, in infecting and in immunodepressing its amphipod host, Gammarus pulex. We also assessed the covariation between infectivity, parasite-induced immune depression and host mortality (parasite virulence). We found that infectivity, the intensity of immunodepression and virulence were variable among parasite sibships. Infectivity and the level of immunodepression were not correlated across parasite sibships. Whereas infectivity was unrelated to host mortality, we found that gammarids that were exposed to the parasite sibships that immunodepressed their hosts the most survived better. This positive covariation between host survival and immunodepression suggests that gammarids exposed to the less immunodepressive parasites could suffer from damage imposed by a higher activity of the phenoloxidase.  相似文献   

5.
Peach palm (Bactris gasipaes Kunth) is cultivated for fruit and heart of palm, and is an important component of agroforestry systems in the Peruvian Amazon. In this study, AFLP was used to compare genetic diversity among domesticated populations along the Paranapura and Cuiparillo rivers, which are managed by indigenous and colonist farming communities, respectively. Gene diversity was 0.2629 for the populations in indigenous communities and 0.2534 in colonist communities. Genetic differentiation among populations (Gst) was 0.0377–0.0416 (P<0.01) among populations along both rivers. There was no relation between genetic differentiation and the geographical location of populations along the rivers. Since natural seed dispersal by birds and rodents is thought to occur only across relatively short distances (100–200 m), it is likely that exchange of material by farmers and commercial traders is responsible for most of the long-distance (over more than 20 km) gene flow among populations along the two rivers studied. This exchange of material may be important to counteract the effects of selection as well as genetic drift in small groups of trees in farmers fields, much as in a metapopulation, and may account for the weak genetic differentiation between the two rivers (Gst=0.0249, P<0.01). A comparison with samples from other landraces in Peru and Brazil showed the existence of an isolation-by-distance structure up to 3,000 km, consistent with gene flow on a regional scale, likely mediated by trade in the Amazon Basin. Results are discussed with regard to practical implications for the management of genetic resources with farming communities.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by H.F. Linskens  相似文献   

6.
Previous studies of Trachypithecus species indicated that they were selective feeders that concentrated on relatively few food species/items. From January to December 2005, I quantified potential food availability and the food species/items eaten by five groups of François' langur (Trachypithecus francoisi) in the Mayanghe Nature Reserve (MNR), People's Republic of China. These langurs fed on 164 species, of which the top ten accounted for 51% of all feeding records. Langurs consumed more species (91) in the spring than in other seasons (73 summer, 75 autumn, and 67 winter), and only 38 species were consumed in all seasons. Nontree food species, such as bushes and lianas, accounted for 47% of the total feeding records and for a majority (68%) of the feeding records in winter. The annual diet consisted of leaves (64% of feeding records), fruit and seed (32%), and other nonfoliage items (4%); the langurs switched from being more folivorous in spring (93%) and summer (79%) to being more frugivorous in autumn (53%) and winter (56%). There was no correlation between the proportion of feeding records and the food availability in the most frequently consumed species, indicating that these langurs were selective feeders; there were significant correlations between consumption and abundance in both the entire set of 112 food species and the set of 86 infrequently consumed species, indicating that foods that are more available are eaten more frequently. It appeared that in the seasonal and disturbed habitat, feeding decisions and diet composition of the langur may be driven more by food availability, and less by animal's selectivity, than at other sites. The results indicate that François' langur copes with habitat alterations by broaden its dietary breadth; this has implications for the adaptive significance of dietary breadth, and has implications for future conservation strategies for species which exist in degraded habitats. Am. J. Primatol. 73:1176–1187, 2011. © 2011 Wiley Periodicals, Inc.  相似文献   

7.
Tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] often benefits in terms of productivity and persistence when infected with Neotyphodium coenophialum ([Morgan-Jones and Gams], Glenn, Bacon, and Hanlin) endophyte, but the influence of novel non-ergogenic endophytes is unclear. We conducted a field experiment using container-grown tall fescue plants to determine how plants allocated resources when clipped repeatedly in microsites differing in the amount of available light associated with open (full sun), and partially shaded (about 20 or 40% of full sun) conditions. Plants of the same tall fescue cultivar (Jesup) were host to either a native or novel non-ergogenic fungal endophyte (MaxQ™), or were devoid of endophyte. Seedlings of plants infected with the novel endophyte had slower germination, germinated later, and allocated more photosynthate to shoots than roots, when compared to J− or J+ plants. Herbage production of undisturbed canopies was not influenced by host–endophyte association within a microsite, with more herbage produced at the open than at the heavily shaded site. Clipping plants to a 5- or a 10-cm residue height tended to accentuate differences, with diminished productivity and greater variability occurring when plants were maintained at 5 cm. This trend was supported by allometric resource allocation patterns, and in terms of vegetative propagule mass relative to the number of propagules. Tall fescue, irrespective of host–endophyte association, grown as forage in silvopastoral situations should be managed to maintain no less than a 10-cm residual plant height. Trends in photosynthate allocation and plant size might influence persistence and should be investigated for more than two growing seasons.  相似文献   

8.
The indoor air quality (IAQ) in classrooms highly affects the health and productivity of students. This article aims to clarify seasonal variation in indoor environment and sick building syndromes (SBS) symptoms in an Eastern Mediterranean climate. A series of field measurements were conducted during the fall and winter seasons from October 2011 to March 2012 in 12 naturally ventilated schools located in the Gaza Strip. Data on environmental perception and health symptoms were obtained from 724 students by using a validated questionnaire. The results showed that indoor PM10 and PM2.5 concentrations were 426.3 ± 187.6 μg/m3 and 126.6 ± 94.8 μg/m3, respectively. The CO2 concentrations and ventilation rate widely exceeded their reference values during the winter season. The prevalence rates of general symptoms were relatively high at baseline assessment in the fall season and increased significantly during follow-up in the winter season. Significant increases in disease symptoms such as mucosal irritation and pre-existing asthma symptoms among students could be related to poor indoor air quality. Five distinct groups of SBS symptoms from factor analysis of students’ related symptoms were significantly correlated with PM10 and PM2.5, CO2, ventilation rate, and indoor temperature. As vulnerable children, this situation negatively affects their school performance and health.  相似文献   

9.
《新西兰生态学杂志》2011,34(3):277-287
Despite periods of extensive government-funded control, fluctuating commercial exploitation and ongoing recreational hunting, little is known about how red deer (Cervus elaphus scoticus L?nnberg) in New?Zealand respond to the cessation of harvesting in terms of population growth rate and resource use. We describe the population dynamics and resource use of red deer in a montane catchment over 5?years (1962?67) following cessation of intensive government-funded control in 1961. Locations and sex?age classes of deer were observed monthly along a fixed route in the Harper-Avoca catchment, inland Canterbury. A total of 2036 red deer groups were observed. The number of groups observed annually increased during the study but no trends in median (2 or 3) or modal (1 or 2) group sizes were found. Population growth rates (r) of deer were extraordinarily high in the first two years (e.g. 2.33 ? 0.22 for adult females and 1.61 ? 0.23 for adult males), but decreased in subsequent years and were not biologically possible without substantial immigration and/or changes in detectability of deer. Sexual segregation and selection of vegetation types (alpine grassland, montane grassland, and forest) and 10 topographic landforms showed stronger intra-annual than inter-annual patterns. Segregation was greatest in spring and summer, least in the rut, and variable in winter. In all seasons, sexual segregation was greatest at 25- and 50-ha scales, moderate at 100-ha, and absent at the 500- and 1000-ha scales. Selection of vegetation types also varied seasonally, with deer of both sexes preferring montane grasslands in spring and summer and alpine grasslands in the rut. Backslopes were preferred landforms in spring and summer, spurs during spring and the rut, and hollows during the rut. Our results highlight the need to consider spatial scale, immigration, and detectability in the design of red deer culling and harvesting programmes. Studies of home-range size and use, migration patterns, dispersal rates and distances are required to better understand the impacts of red deer on New?Zealand ecosystems and the effects of management on red deer populations.  相似文献   

10.
11.
Abstract

Alpine conifers produce pulsed resources for the community of tree‐seed consumers. Here, we describe field and statistical methods to estimate spatio‐temporal variation in seed‐crops in forests with different species composition. Annual and between‐site variation in seed production was high and characterised by occurrence of mast‐crops followed by seed‐crop failure the following year. Seed‐crops of different species did not fluctuate in parallel.

Abbreviations: DLSM, differences of least square means; CED, Cedrasco; OGA, Oga; VAL, Valfurva; BOR, Bormio; RHE, Rhemes; COG, Cogne  相似文献   

12.
The aim of this study was to examine sex differences in sleep‐time preference by age among Italian pre‐adolescents, adolescents, and adults. The final sample consisted of 8,972 participants (5,367 females and 3,605 males) from 10 to 87 yrs of age. To assess preferred sleep habits, we considered the answers to the open‐ended questions of the Morningness‐Eveningness Questionnaire (MEQ). In agreement with previous studies, we found that sleep‐time preference started to shift toward eveningness from the age of 13 yrs. Females reached their peak in eveningness earlier (about 17 yrs of age) than males (about 21 yrs of age). Thereafter, the ideal sleep‐time preference advanced in men and women with increasing age. Females presented a more significant advanced sleep phase than males only during the years when sexual hormones are typically active. Moreover, females reported a longer ideal sleep duration than males across all age groups examined, except in over 55 yrs one. (Author correspondence: )  相似文献   

13.
14.
BackgroundIn the Karunagappally cohort, esophageal cancer is the third most common cancer with an age-adjusted incidence rate of 6.2 per 100,000 person-years among men. The present study analyzed the risk of esophageal cancer in relation to alcohol drinking and tobacco use.MethodsThe study included 65,528 men aged 30–84 years in the Karunagappally cohort, India.ResultsPoisson regression analysis showed that alcohol drinking significantly increased (P = 0.027) the risk of esophageal cancer and the relative risk (RR) for current drinkers was 1.6, (95 % confidence interval (CI) = 1.1–2.3). The risk increased significantly in heavy alcohol drinkers (250 g of ethanol or above per day) (RR = 2.1, 95 % CI = 1.2–3.5) (P for trend = 0.014) and among current arrack consumers (RR = 1.8, 95 % CI = 0.99–3.29) (P for trend = 0.025). Current bidi and cigarette smokers showed an increase in the trend of cancer risk. A significantly higher risk was seen in those who had started smoking bidi before the age of 18 years, RR = 1.9 (95 % CI = 1.1–3.3) (P for trend = 0.044). Furthermore, increased RR for heavy bidi and cigarette smokers were 1.6 (95 % CI = 1.1–2.5) and 2.4 (95 % CI = 1.3–4.5), respectively.ConclusionTo the best of our knowledge, this is the first cohort study in India to report an increased esophageal cancer risk with respect to alcohol drinking.  相似文献   

15.
This study focused on intra and interspecific variations in the diet of small species in the Pelotas River, upper Uruguay River ecoregion. We tested the hypothesis that five small characids coexist via resource partitioning. Samplings were performed quarterly between August 2013 and May 2014 at 14 sites in the Pelotas River basin, using gillnets of different mesh sizes, seines, cast nets and electrofishing. In this study, the contents of 1,253 stomachs were analysed from Astyanax dissensus, A. paris, A. saguazu, A. xiru and Bryconamericus patriciae. The main food resources consumed were aquatic insects, leaves, seeds and detritus. There were significant seasonal intra and interspecific variations in the use of food resources by the five species. Permutational analysis of multivariate dispersions results indicated significant differences in individual intraspecific variability between the sampled periods, with the highest values found in November and February because of an increase in allochthonous resources (leaves and seeds). Besides this, significant differences in the proportions of consumption of allochthonous and autochthonous were observed. The trophic niche breadth was significantly different among the species, such that in August, the species had narrower niche breadths. In the other periods, the highest niche breadth values were due to an increase in the consumption of allochthonous items. Diet overlap was low (< 0.4) between 62% of the species pairs. The small characid species showed pronounced changes in resource use and intra and interspecific variations indicating resource partitioning. These factors appear to be essential in species interactions and for coexistence.  相似文献   

16.
17.
Discrimination of stable isotopes of carbon (δ13C) and nitrogen (δ15N) was examined for the amphipod Allorchestes compressa Dana using controlled laboratory experiments. Amphipods were fed exclusively on single diets (fresh or decomposed macroalgae or seagrass) for three weeks. Macrophyte type (i.e. seagrass, brown algae or red algae) had a greater influence on the stable isotope ratios of A. compressa than the state of decomposition of the macrophyte material. The experiments revealed that δ13C in A. compressa stabilised at values lower than those of the diets, which contrasts to the general assumption that consumer-diet discrimination of δ13C ranges from 0 to + 1‰. Amphipods fed on seagrass yielded the lowest δ13C values, which were 9 to 10‰ lower than their diet, while amphipods fed on macroalgae had values 2 to 4‰ lower than their diet. In addition, contrary to the general assumption that consumer-diet discrimination of δ15N ranges from + 3 to + 5‰, discrimination of δ15N was as low as − 1 and + 1 when A. compressa was fed on brown and red algae, respectively, but as high as + 3‰ when fed on seagrass. The results show that discrimination of stable isotopes of carbon and nitrogen can vary considerably depending on the food source, demonstrating that validation of assumptions about discrimination are critical for interpreting stable isotope data from field studies.  相似文献   

18.
The feeding ecology of two sympatric gobies, Favonigobius lentiginosus and Favonigobius exquisitus, which inhabit soft substrate pools was studied in Moreton Bay, Australia. Favonigobius spp. and sediment cores were collected from three locations within the bay and fish gut contents were analysed to explore potential competition and ontogenetic dietary shifts. The most abundant prey at all sites was nematodes at 6.33 ± 0.38 cm(-3) at Dunwich, 33.58 ± 0.26 cm(-3) at Manly and 6.36 ± 0.849 cm(-3) (mean ± S.E.) at Godwin Beach. Nevertheless, they were not a dominant component of the diets. Volumetric percent contribution of prey showed that copepods and decapod shrimps dominated F. lentiginosus diets at Dunwich (7.8 and 6.6%, respectively) and Godwin Beach (6.5 and 14.3%, respectively) and the diets of F. exquisitus at Manly (9.2 and 9.5%, respectively) and Godwin Beach (10.4 and 11.8%, respectively). Schoener's index of dietary overlap between the two species, when sympatric, was 0.85 indicating a high similarity. An ontogenetic shift towards larger prey items occurred as Favonigobius spp. reached larger sizes. Gut fullness indices showed significant differences between time of day (two-way ANOVA, P < 0.01) and species (two-way ANOVA, P < 0.05) but Bonferroni's multiple comparison test showed that the only significant difference was between F. lentiginosus at Dunwich and F. exquisitus at Godwin Beach at 1800 hours. Food resource competition and temporal resource partitioning did not appear to be a limiting factor between F. lentiginosus and F. exquisitus despite cohabitation in such restricted environments.  相似文献   

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Capsule Migrant Willow Warblers occupy more woodland types and occur at higher densities than ecologically‐similar resident Afrotropical warblers.

Aims To compare population densities of Willow Warblers and eremomelas in adjacent acacia, mopane and miombo woodlands, and assess the abundance of potential invertebrate prey in each habitat type, in order to investigate whether Palearctic migrants use more open habitats and are more flexible in habitat use than their Afrotropical counterparts in the same feeding guild.

Methods Using distance sampling we carried out four replicated sets of point counts in acacia woodland and three sets of counts in miombo and mopane between December 1999 and February 2000. We noted the tree species in which we saw warblers foraging and took beating‐tray samples of potential arthropod prey present on tree foliage in each of the three habitats.

Results Willow Warbler density in acacia woodland increased from 1.80 ± 0.54 (se) birds/ha in early December to 7.15 ± 1.41 birds/ha in late January after influxes of later arrivals. Densities of Willow Warblers in miombo and mopane were much lower (1.14 ± 0.28 and 0.38 ± 0.23 birds/ha, respectively) and did not show significant changes. Burnt‐necked Eremomelas averaged 0.74 ± 0.34 birds/ha in acacia woodland, and in miombo densities of Green‐capped and Yellow‐bellied Eremomelas were 0.23 ± 0.17 and 0.34 ± 0.26 birds/ha, respectively. Densities in mopane were too low to estimate reliably. Willow Warblers and Green‐capped Eremomelas showed some apparent preferences in tree species used for foraging but differences in tree use were not obviously related to the abundance of arthropod taxa present as potential prey.

Conclusion Willow Warblers occupied more habitats at greater density than similar Afrotropical warblers. They appear to favour acacia, but their settlement patterns and the reasons for disparities between densities of immigrants and residents are unclear.  相似文献   

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