Search results for "Seasonal variation"
showing 10 items of 15 documents
Seasonal changes in morpho-functional aspects of two Anemonia sulcata (Pennant, 1777) wild populations
2017
Marine benthic organisms can be used as indicators of the quality of environmental status and as monitoring tools to detect natural or anthropogenic perturbations. In temperate waters, metabolic and biochemical responses may be governed by physiological changes driven by seasonal factors. Gathering baseline information on the mechanisms underlying seasonal acclimation patterns is therefore a critical step towards the understanding of the physiological responses of biological indicators. In poikilothermic metazoans, the production of regulatory metabolic enzymes can be used as tools for deciphering the acclimation potential. The aim of this study was to characterize the natural seasonal vari…
Seasonal variations in the onset and healing rates of venous leg ulcers
2010
Objectives As many vascular pathologies exhibit circannual fluctuation, the aim of this study was to assess the chronobiological features of venous ulcers. Methods Based on a retrospective survey of the case histories of 391 venous ulcer patients, the rates of ulcer onset and healing in each month were analysed statistically; a time series was constructed to evaluate the seasonality. Results There was a significantly higher frequency of ulcer onset during the warmer part of the year (April–October), and onset showed strong seasonality. Healing rates were also unequally and statistically significantly distributed throughout the year: ulcers that appeared or that were treated with specialized…
An Investigation of the Seasonal Pattern of Mannitol Content in Deciduous and Evergreen Species of the Oleaceae Growing in Northern Sicily
2002
In several species of the Oleaceae, mannitol, already present at considerable levels, accumulates in response to stress. This family comprises both deciduous and evergreen species, and we investigated the role of mannitol in deciduous malacophyll and evergreen sclerophyll species growing under the same conditions in the field. The relationship between mannitol content and changes in rainfall or temperature was also studied. The mannitol content of leaves of Fraxinus ornus L., F. angustifolia Vahl., Olea europaea L. and Phillyrea media L. was determined by gas chromatography. Leaf samples were collected once a month for 1 year. In the two ash species, the seasonal pattern of mannitol content…
Seasonal variations of antimicrobial activity and chemical composition of essential oils extracted from three Citrus limon L. Burm. cultivars
2014
In order to investigate the seasonal variations of antimicrobial properties and chemical composition of essential oils (EOs), three different cultivars of Citrus limon L. Burm. spp. (Femminello Santa Teresa, Monachello and Femminello Continella) were collected at 6-week intervals, from December 2012 to April 2013, for a total of four harvests. The EOs were extracted from lemon peel by hydro-distillation. The antimicrobial activity, tested by paper disc diffusion method, was evaluated against common food-related pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Enterobacter spp.). EOs were more effective against Gram-positive than Gram-negative bacte…
Influence of the Madden-Julian Oscillation on Southern African summer rainfall
2007
Rain-causing mechanisms over Southern Africa (south of 15˚S) involve both tropical and temperate dynamics. Most studies focused on the synoptical timescale, while the intraseasonal (20-120 days) variability has more been neglected to date. This study aims at determining whether the dominant mode of intraseasonal variability in the Tropics, namely the Madden-Julian Oscillation (MJO), has a significant impact on Southern African rainfall and associated atmospheric dynamics. The examination of outgoing longwave radiation (OLR) over Southern Africa shows indeed significant intraseasonal fluctuations at the 30-60 day timescale, i.e. in the pe- riods that are typically reminiscent of the MJO. In ord…
Measuring tourism seasonality across European countries
2018
Abstract This paper will propose a general approach for the analysis and measurement of seasonality in tourism, based on an analysis of the pattern of seasonal swing, as a preliminary step for the assessment of seasonal amplitude. The seasonality of tourism demand across European countries will be analyzed and clusters of countries identified, which are based on a similarity of their seasonal pattern. After discussing the limitations of the most frequently used indices employed in the tourism literature, a new index for measuring seasonality in tourism will be suggested in order to measure seasonal amplitude. The latter takes into account the ordinal and cyclical structures of seasonal vari…
Seasonal pattern of mannitol and malate accumulation in leaves of two manna ash species (Fraxinus ornus L. and F. angustifolia Vahl) growing in Sicily
2002
The content of mannitol and malate was assayed enzimatically during spring, summer and autumn, in leaves of two species of ash traditionally cultivated in Sicily for the extraction of manna. The results suggest that in these species, under the local field conditions, mannitol has a more relevant role than malate in the response to summer drought.
Seasonality of Congenital Anomalies in Europe
2014
BackgroundThis study describes seasonality of congenital anomalies in Europe to provide a baseline against which to assess the impact of specific time varying exposures such as the H1N1 pandemic influenza, and to provide a comprehensive and recent picture of seasonality and its possible relation to etiologic factors. Methods: Data on births conceived in 2000 to 2008 were extracted from 20 European Surveillance for Congenital Anomalies population-based congenital anomaly registries in 14 European countries. We performed Poisson regression analysis encompassing sine and cosine terms to investigate seasonality of 65,764 nonchromosomal and 12,682 chromosomal congenital anomalies covering 3.3 mi…
Seasonality in tourism: a critical review of its main measures
2008
The purpose of this study is to estimate the risk of second primary cancer (SPC) in 129 consecutive patients with splenic marginal zone lymphoma (SMZL) diagnosed in three Italian haematological centres. The person-years method deriving as a sum ofproducts ofage- and sex- specific rates and ofthe corresponding time at risk was used. The SPC Standardized Incidence Ratio ISIR) was 2.03 with a 95% confidence interval: [1.05,3.56] (p < 0.05) and the corresponding Absolute Excess Risk (AER) was 145.8 (per 10000 SMZL patients per year). Our findings evidence a high frequency of additional cancers in patients with SMZL and suggest that the incidence rate of SPCs is significantly different from that…
Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital
2009
International audience; A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn…