Search results for "seasonal"
showing 10 items of 484 documents
Bean goose migration shows a long-term temporal shift to earlier spring, but not to later autumn migration in Finland
2023
Ilmastonmuutos vaatii eliöitä mukauttamaan perinnöllisiä tai opittuja käyttäytymismallejaan muuttuviin ympäristöolosuhteisiin. Erityisen alttiita muutoksille voi olla erilaisten habitaattien välillä muuttavat linnut, joiden selviytyminen on yhteydessä muuton onnistuneeseen ajoittamiseen. Tässä tutkimuksessa käytimme metsähanhesta (Anser fabalis) avoimeen lintutietopalveluun, Tiiraan (tiira.fi – BirdLife Suomi), kerättyjä havaintoja selvittääksemme, onko lajin muuton ajoituksessa tapahtunut muutosta viimeisten 40 vuoden aikana. Lisäksi selvitimme ajoituksen yhteyttä muuton aikaiseen suursäätilaan käyttämällä Pohjois-Atlantin suursäätilaa kuvaavaa NAO-indeksiä. Tutkitulla ajanjaksolla 1978–20…
Seasonal variations in endurance performance, and aerobic and anaerobic variables in competitive cross country skiers
2016
Cross country skiing is known as an endurance sport and both aerobic and anaerobic systems have a major impact on performance in cross country skiers. Coaches and athletes use periodized training programs to optimize physiological adaptations and increase performance. Knowing how the major aerobic and anaerobic variables change during the course of one ski season will allow better implementation of training programs. This study examined variations in endurance performance, and how that relates to the variation in different aerobic and anaerobic variables. There were 19 subjects in the study, 11 male and 8 female. All subjects were competitive cross country skiers. The study took place over …
Personal and Environmental Risk Factors at Birth and Hospital Admission: Direct and Vitamin D-Mediated Effects on Bronchiolitis Hospitalization
2021
Abstract: Seasonal variations in UV-B radiation may influence vitamin D status, and this, in turn, may influence the risk of bronchiolitis hospitalization. The aim of this study was using a causal inference approach to investigate, simultaneously, the interrelationships between personal and environmental risk factors at birth/hospital admission (RFBH), serum vitamin D levels and bronchiolitis hospitalization. A total of 63 children (<2 years old) hospitalized for bronchiolitis (34 RSV-positive) and 63 controls were consecutively enrolled (2014-2016). Vitamin D levels and some RFBH (birth season, birth weight, gestational age, gender, age, weight, hospitalization season) were recorded. The d…
Zivju sabiedrības sezonālās izmaiņas Liepājas ostas akvatorijā saimnieciskās darbības ietekmē
2021
Darbā analizēta Liepājas ostas akvatorijas zivju sabiedrība, tās sezonālās izmaiņas, un to galvenie ietekmējošie faktori. Datu ievākšana, veicot kontrolzveju ar zinātniskajiem tīkliem trīs gadu garumā, četrās sezonās (rudens, ziema, pavasaris, vasara) sniedz precīzu ieskatu par zivju sugu sezonālajām izmaiņām. Papildus ievāktie hidroloģiskie dati ļauj spriest par galvenajiem ietekmējošajiem faktoriem. Darbu vēl unikālāku padara vienā no pētījuma posmiem veiktā ostas padziļināšana, izceļot grunti, kas ļauj ne tikai novērtēt papildus faktoru ietekmi uz zivju sugu mainību, bet izdarīt secinājumus arī par saimnieciskās darbības ietekmi uz zivju sabiedrību akvatorijā, novērot ostas ekosistēmas a…
La non stationnarité dans les séries saisonnières. Application au tourisme tunisien
1998
The purpose of the paper is to specify the nature of the seasonal behaviors of tourist stay demand in Tunisia by using recent tools of monthly time series analysis. The available series (tourist expenditures, prices, guest nights, reception capacities,...) are analyzed with the classical theory of demand and the theory of supply induced demand. Empirical results show that these series are generated by non stationary processes which seasonality is stochastic and deterministic. The extent of the maximum likelihood method proposed by Lee (1992) for monthly data emphasizes unit roots and cointegration relationships at some seasonal frequencies. Error correction models are derived for endogenous…
Climate change and reindeer management in Finland : Co-analysis of practitioner knowledge and meteorological data for better adaptation
2020
We studied interannual variability and changes over time in selected climate indices in the reindeer management area (RMA) in northern Finland. We present together the knowledge possessed by reindeer herders with information from meteorological measurements over three decades. The practitioner knowledge was gathered via a survey questionnaire addressing herder observations of long-term changes (approximately during the past 30 years) in climatic conditions and their impacts on herding during the four seasons. A set of temperature-, precipitation- and snow-related indices relevant for herding within the RMA was derived from spatially interpolated daily meteorological data (1981–2010). Climat…
Environmental factors modulating cold tolerance, gene expression and metabolism in Drosophila montana
2011
Mathematical Methods for Research Excellence : Book of Abstracts
2022
Design of a Cleaning Program for a PV Plant Based on Analysis of Energy Losses
2015
Solar photovoltaic (PV) energy has grown significantly over the past few years. However, despite the increase in installed capacity, this energy source still raises important concerns related to the variability of power production. The short-term effects such as cloud shadowing and supply interruptions, as well as long-term effects such as dust accumulation, seasonal variation, and ageing of PV modules, can cause variability of power production. Therefore, the analysis of all the variability sources in order to provide statistically consistent power production data is an important challenge. This study presents a methodology to analyze data from a PV plant in order to have an independent ev…
The measurement of seasonality for tourism evaluation
2017
Seasonal variations in tourism demand represent one of the most challenging topics in tourism research. After highlighting the main pitfalls which characterize the majority of currently used indices for seasonal amplitude, the present work propose the implementation of a recently discusses a recently proposed index for the measurement of seasonality in tourism, based on the transportation problem approach. An adequate measurement of seasonality is a pre-requisite for the evaluation of the effectiveness of tourism policies aimed at reducing tourism demand imbalance.