Search results for "Seasonality"
showing 10 items of 229 documents
How does seasonality affect water reuse possibilities? An efficiency and cost analysis
2012
Abstract Because of the harsh conditions of water stress and seasonal water demand in many zones, water reuse has emerged as a key alternative for achieving sustainable water management. An efficient performance by wastewater treatment plants (WWTPs) in technical and economic terms favors water reuse. However, seasonality in the flow of wastewater and in the pollutant load may be a determining factor in the efficiency of WWTPs. To evaluate if seasonality affects WWTP efficiency, analytical benchmarking methodology Data Envelopment Analysis (DEA) is used to obtain an average efficiency score for seasonal and non-seasonal plants. Given the importance of extended aeration (EA) and activated sl…
A Study of Seasonality on the SAFEX Wheat Market
2015
This paper examines seasonality in returns and volatilities in the South African Futures Exchange (SAFEX) wheat futures contract in order to seek market inefficiencies that can be exploited for financial gain. Non-parametric and parametric-based techniques are used to study sample regimes before and after the peak in wheat prices that occurred during the global economic crisis in 2008. Findings of the study indicate that wheat returns on Mondays and Kansas City Board of Trade (KCBT) holidays are significant and positive while Tuesday returns are negative and significant. These seasonal patterns occur largely in the second sample of the wheat dataset. Furthermore, it is observed that volatil…
A critical view on temperature modelling for application in weather derivatives markets
2012
In this paper we present a stochastic model for daily average temperature. The model contains seasonality, a low-order autoregressive component and a variance describing the heteroskedastic residuals. The model is estimated on daily average temperature records from Stockholm (Sweden). By comparing the proposed model with the popular model of Campbell and Diebold (2005), we point out some important issues to be addressed when modelling the temperature for application in weather derivatives market.
Biometric analysis of Brachionus plicatilis ecotypes from Spanish lagoons
1983
Univariate comparisons and several multivariate statistical analyses have been performed to study the morphometric variability of B. plicatilis. Both laboratory clones kept under constant conditions and natural populations from different Spanish lagoons and different times of the year have been compared. The results show that not only size, but also allometric coefficients are influenced by environmental factors. However, an important genetic component in the variation of shape and size has been visualized. A clear North-South ordination of the populations of the different lagoons and an important dispersion between their summer populations as well as great differences due to seasonal varia…
The predictability of international terrorism: A time‐series analysis
1988
Abstract The study examines the predictability of international terrorism in terms of the existence of trends, seasonality, and periodicity of terrorist events. The data base used was the RAND Corporation's Chronology of International Terrorism. It contains the attributes of every case of international terrorism from 1968 to 1986 (n = 5,589). The authors applied Box‐Jenkins models for a time‐series analysis of the occurrence of terrorist events as well as their victimization rates. The analysis revealed that occurrence of terrorist events is far from being random: There is a clear trend and an almost constant periodicity of one month that can be best described by a first‐order moving averag…
PM2.5-bound oxygenated PAHs, nitro-PAHs and parent-PAHs from the atmosphere of a Chinese megacity: Seasonal variation, sources and cancer risk assess…
2014
Polycyclic aromatic compounds (PACs) in air particulate matter contribute considerably to the health risk of air pollution. The objectives of this study were to assess the occurrence and variation in concentrations and sources of PM2.5 bound PACs [Oxygenated PAHs (OPAHs) nitro PAHs and parent PAHs] sampled from the atmosphere of a typical Chinese megacity (Xi'an) to study the influence of meteorological conditions on PACs and to estimate the lifetime excess cancer risk to the residents of Xi'an (from inhalation of PM2.5 bound PACs). To achieve these objectives we sampled 24 h PM2.5 aerosols (once in every 6days from 5 July 2008 to 8 August 2009) from the atmosphere of Xi'an and measured the…
Seasonal response of vegetation on pollutants removal in constructed wetland system treating dairy wastewater
2022
Constructed wetland systems provide the ideal solution for small and medium dairy farms as they can be built close to the farm and are easy to manage and use. However, their perfomance is significantly affected by vegetation activity during the year. The aims of the present study were to assess the treatment of dairy wastewater (DWW) by a horizontal subsurface flow system (HSSFs) and the effect of plants in the removal efficiency (RE) of BOD5, COD, total N (TN) and total P (TP), in Sicily (Italy). The HSSFs treated 6/7 m3 per day of wastewater produced by a small dairy farm subsequent to biological treatment. The system included two units which were separately planted with Arundo donax L. a…
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…
Impact of climate change and man-made irrigation systems on the transmission risk, long-term trend and seasonality of human and animal fascioliasis i…
2014
Large areas of the province of Punjab, Pakistan are endemic for fascioliasis, resulting in high economic losses due to livestock infection but also affecting humans directly. The prevalence in livestock varies pronouncedly in space and time (1-70%). Climatic factors influencing fascioliasis presence and potential spread were analysed based on data from five mete- orological stations during 1990-2010. Variables such as wet days (Mt), water-budget-based system (Wb-bs) indices and the normalized difference vegetation index (NDVI), were obtained and correlated with geographical distribution, seasonality patterns and the two-decade evolution of fascioliasis in livestock throughout the province. …
Seasonal dynamics of egg laying and egg-laying strategy of the ectoparasite Argulus coregoni (Crustacea: Branchiura).
2004
Substrate preferences, spatial aggregation patterns and seasonal dynamics in the egg laying of ectoparasiticArgulus coregoniwere studied at a commercial fish farm in Finland. Pilot experiments showed thatA. coregonifemales selected specific types of substrates for egg laying. Significantly moreA. coregonieggs were laid on dark substrates than on light ones suggesting the use of visual cues. Therefore, egg-laying plates of dark colour were constructed for further experiments. MostA. coregonieggs were deposited in locations in shadow and in the deepest water in a 2 m deep farming canal. Relatively more eggs were laid on bottom stones situated near each egg-laying trap than on artificial egg-l…