Search results for "Seasonality"

Variability in δ13C values between individual Daphnia ephippia: Implications for palaeo-studies

2018

The stable carbon isotope ratio (δ13C value) of Daphnia spp. resting egg shells (ephippia) provides information on past changes in Daphnia diet. Measurements are typically performed on samples of ≥20 ephippia, which obscures the range of values associated with individual ephippia. Using a recently developed laser ablation-based technique, we perform multiple δ13C analyses on individual ephippia, which show a high degree of reproducibility (standard deviations 0.1–0.5‰). We further measured δ13C values of 13 ephippia from surface sediments of three Swiss lakes. In the well-oxygenated lake with low methane concentrations, δ13C values are close to values typical for algae (−31.4‰) and the rang…

Measuring Seasonality: Performance of Accommodation Establishments in Sicily through the analysis of Occupancy Rates

2011

Tourism, more than other fields, needs to be managed. As such, the provision of reliable information and adequate tools is one of the major challenges to monitor and to manage tourism destinations. Sicily (Italy) seems to have a great potential coming from its tourism resources, and most of the recent development programs have been focused on tourism. In line with the world’s trend, tourism in Sicily faced a growth in terms of overnight stays, from about 9 millions in 1994, to more than 14 millions in 2007. The regional expenditure in tourism from 1996 to 2006 was of euro 785 millions (Federalberghi, 2007), which ranks Sicily as the second region in Italy for tourism expenditure, in the yea…

Sex-specific and age-related seasonal variations regarding incidence and in-hospital mortality of pulmonary embolism in Germany

2020

Background Studies have reported seasonal variations regarding the incidence and the short-term mortality of pulmonary embolism (PE). The aim of this study was to identify sex-specific and age-related differences in seasonal patterns regarding hospitalisations and mortality of PE patients. Methods We analysed the impact of seasons on incidence and in-hospital mortality of male and female hospitalised PE patients in Germany (2005–2015) based on the German nationwide inpatient sample. Results The German nationwide inpatient sample comprised 885 806 hospitalisations due to PE (2005–2015). Seasonal variations of both incidence (p=0.021) and in-hospital mortality (p<0.001) were of significant ma…

Seasonal variation of air kerma in the "Vulcano Porto" area (Aeolian Islands, Italy).

2001

Abstract Air kerma was measured in the “Vulcano Porto” area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident.

Seasonal cardenolide production and Dop5βr gene expression in natural populations of Digitalis obscura

2004

Productivity variations and seasonal fluctuations of cardenolides have been studied in 10 natural populations of Digitalis obscura distributed in three bioclimatic belts. Main cardenolides in D. obscura plants are those of the series A and such predominance (ca. 80-85%) over the series B metabolites is independent of the population studied or the degree of maturity of the leaves. Primary glycosides represent ca. 50-60% of total cardenolides; this percentage did not vary among populations or with the leaf age but increased in summer and decreased in winter. A correlation analysis between plant biomass and cardenolide content showed a positive relationship of these parameters, which, accordin…

Long-term characterization of trihalomethane levels in drinking water

2010

Water chlorination leads to the formation of trihalomethanes (THM). In this case study, the levels of THM during the chlorination process of the drinking water in Valencia (Spain) were determined over a 12-year period. Different control areas and points were strategically sampled and samples were analyzed by gas chromatography. Temporal tendencies, as well as spatial and seasonal variations, were established. The individual distribution of THM was also evaluated. Factors such as distances from chlorination points and inter-month seasonal distribution, including ambient temperature effect, were assessed. The range of total THM concentrations measured in the water network goes from 4 to 184 µ…

Soil Water Content Diachronic Mapping: An FFT Frequency Analysis of a Temperature–Vegetation Index

2020

Among the indirect estimation approaches of soil water content in the upper layer of the soil, the &ldquo

Seasonal pattern and amplitude: a logical framework to analyse seasonality in tourism. An application to bed occupancy in Sicilian hotels

2011

Many studies have investigated seasonality in tourism in terms of its causes and impacts, from both theoretical and applied perspectives. However, the definition of seasonality and, most of all, its application and measurement have not received the same degree of attention. In recognizing that seasonality has two main facets – pattern and amplitude – this paper critically examines the main seasonality measures proposed in the tourism literature, classifying them according to their properties and their most appropriate use. The framework then proposed is used to analyse a standard and comparable efficiency measure, such as the bed occupancy rate of Sicilian accommodation establishments, pla…

Seasonality in tourism: measures and applications to overnight stays in Sicily

2012

SINGLE FACTOR STOCHASTIC MODELS WITH SEASONALITY APPLIED TO UNDERLYING WEATHER DERIVATIVES VARIABLES

2003

This paper estimates single factor stochastic models describing daily air temperature behaviour. We modify classical financial models to reflect temperature seasonality and fit them to a time series representing temperatures in Spain. The estimated models are used in Montecarlo simulations to obtain heating and cooling degree-days, which are used as an underlying reference in weather derivatives. The final goal of this work is to obtain an insight into weather derivative valuation, and so making it easier to manage economic activity risks closely related to temperature (i.e. oil, gas and electricity prices and volumes). En este trabajo se estiman modelos estocásticos unifactoriales que desc…