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Winter Season (winter + season)
Selected AbstractsInfluence of environmental stress on skin tone, color and melanogenesis in Japanese skinINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005K. Kikuchi Introduction It is needless to say that one of the most potent environmental stress for melanogenesis of the human skin is the effect of ultraviolet (UV) light from the sunlight. Characteristic skin aging as a result of this UV light is recognized as photoaging. Clinical features in photoaging are wrinkles, skin laxity, coarseness, leathery, yellowing, lentigenes, mottled pigmentation, telangiectasia, sebaceous hypertrophy and purpura. There is an apparent difference in clinical features in photoaging among different races, i.e. between Caucasians, African American and Asians that include Japanese. Not only photo skin type but also environmental factors, such as climate, latitude, altitude and their habit of sunbathing, smoking and skin care influence the characteristic development of their photoaging. Racial difference in photoaging Caucasians tend to develop skin laxity and fine wrinkles more than Asians [1]. Asians tend to produce coarser wrinkles than the Caucasians although their development is rather late in life. There is also a difference in the skin color. Pigmentation is an earliest and prominent skin changes in Asians [1] and it increases with age [2]. In contrast, pigmentation is not apparent in the Caucasians although redness probably because of an increase in cutaneous vascularization becomes prominent in middle aged Caucasians [2]. Chung reported that seborrheic keratosis is a major pigmentary lesion in men, whereas hyperpigmented macules are prominent features in women in Koreans [3]. Melanogenesis pigmentation disorders in Japanese Ephelides (freckles) are commonly found in those with photo skin type I who have fair skin and red eyes and blond hair. They are also found in the Japanese. Clinical feature reveals that multiple small pigmentary macules on sun-exposed areas mainly on the mid-portion of the face. These lesions seem to be familial, becoming apparent even in early childhood after sun exposure. Melasma is an acquired pigmentary disorder commonly found in middle aged Japanese women characterized by irregular brown macules and patches on the sun-exposed areas on the face typically as bilaterally present macules on the cheeks. An increase in sex hormones as a result of pregnancy and intake of contraceptive pills is one of the etiological factors to develop melasma. Sun exposure also worsens it. Nevus of Ota is also a common pigmentary disorder found in the Japanese. It is usually unilateral, blue-brown to slate-gray pigmentary macules on the eyelid and cheek that appear in early childhood or in puberty. Acquired dermal melanocytosis is also a pigmentary disorder, in which dermal melanocytes are found as shown in nevus of Ota, characterized by bilateral brown to blue-gray macules on the forehead, temple, eyelid and malar areas in middle aged Japanese women. This tends to be misdiagnosed as melasma. Solar lentigo is an acquired pigmented macule induced by sun exposure. Solar lentigines are usually multiple, circumscribed brown macules. There are two types of solar lentigo. One is a small macular type, characterized by multiple, small brown macules whose diameter is less than 5 mm, being similar to ephelides (freckles). The other type is a large macular type, characterized by a few round to oval, brown macules whose diameter is beyond 1 cm. Some of their surface are hyperkeratotic and become elevated to produce seborrheic keratosis. Again, the early sign of photoaging in Japanese is pigmentated spots and these pigmentation disorders increase with age. Among the pigmentary changes, nevus of Ota, acquired dermal melanocytosis, melasma and large macular type of solar lentigo are characteristic skin changes found in the Japanese in addition to ephelides and small macular type of solar lentigo. Seasonal changes of the various functional properties of the skin including skin color assessed by non-invasive bioengineering techniques [4]. When we consider skin tone, color and melanogenesis, UV light from the sunlight is the most potent environmental stress, although we cannot forget also the important influence of environmental relative humidity affects our skin functions as well as its appearance. We investigated seasonal influences on the various properties of the skin in 39 healthy Japanese females consisting of different age groups. Their skin is thought to be affected by the UV light in summer, and by the exposure to the dry and cold air in winter. Materials and methods Biophysical, non-invasive measurements, including transepidermal water loss (TEWL) as a parameter for the barrier function of the stratum corneum (SC), high frequency conductance as a parameter for the hydration state of the SC, skin color and casual surface lipid levels, were conducted during late summer and winter months. Skin color was determined with a chromameter according to the L*a*b* CIE 1976 system, where L* is an attribute on the luminance scale, a* that on the red versus green scale and b* that on the yellow versus blue scale. All the measurements were conducted in an environment controlled-chamber (21 ± 1 °C room temperature, and 50 ± 3% relative humidity). Results The barrier function of the SC was found to be significantly impaired in winter on the cheek as compared with that measured in summer, whereas no such seasonal change was apparent both in the hydration state of the SC and sebum levels on the cheek. In the assessment of the skin color on the cheek, a significant increase in a* (redness) and a decrease in b* (yellowness) were observed in winter. In contrast, on the flexor forearm, the values of L* (luminescence) increased in winter, but no seasonal change was noted in the values of a* and b*. In this study, skin changes with aging were also found by the non-invasive bioengineering methods. The value of TEWL on the cheek tended to increase with age, whereas no significant change was observed in the value of TEWL on the forearm. In the assessment of skin color, b* value on the cheek significantly increased with age whereas a* and L* values on the cheek did not show any significant change with age. Summary of this study We think that such an increase in yellowness with aging of the cheek skin is a phenomenon unique to the Japanese (Asians) since an increase in b* value was not observed in Caucasians [2]. The facial skin that is always exposed shows barrier impairment in a dry and cold winter environment and demonstrates increased yellowness in skin color because of a prolonged exposure to the UV light from the sun in the summer season. The non-invasive bioengineering methods are useful to demonstrate even invisible seasonal changes occurring in the same individuals and changes with age occurring in the skin. References 1.,Goh, S.H. The treatment of visible signs of senescence: the Asian experience. Br. J. Dermatol.122, 105,109 (1990). 2.,LeFur, I., Numagami, K., Guinot, C. et al. Age-related reference values of skin color in Caucasian and Japanese healthy women according to skin site. Pigment Cell Res. 7, 67 (1999). 3.,Chung, J.H., Lee, S.H., Youn, C.S. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 4.,Kikuchi, K., Kobayashi, H., Le Fur, I. et al. Winter season affects more severely the facial skin than the forearm skin: comparative biophysical studies conducted in the same Japanese females in later summer and winter. Exog. Dermatol. 1, 32,38 (2002). [source] Glucose, fructose and sucrose content in broccoli, white cabbage and Portuguese cabbage grown in early and late seasonsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2001Eduardo Rosa Abstract Consumption of Portuguese cabbage and white cabbage is very high in Portugal, but diets including broccoli have been highly recommended owing to recognition of the health-protective effects of secondary plant metabolites. Broccoli production is generally concentrated in the summer/winter season, but the demand for a fresh product throughout the year requires production in other seasons. Sugars might affect flavour and the acceptance of broccoli by consumers. This study reports the free fructose, glucose and sucrose content in primary and secondary inflorescences of 11 cultivars of broccoli, one white cabbage and four Portuguese cabbages grown in early (March,July) and late (August,January) seasons in the northern region of Portugal. On average the results show that the total free sugar content in the broccoli cultivars, except for cv Marathon, is significantly (P,<,0.05) lower than in the other cabbages. Fructose was the major sugar in the three types of Brassica, representing between 48.8 and 56.9% of the total sugar content in broccoli cvs Marathon and Senshi respectively and between 48.7% (cv Mirandela) and 53.8% (cv Murciana) in the other cabbages. Glucose was the second major sugar, while sucrose represented a maximum of 20.5% in broccoli cv Shogun and 11.1% in cv Murciana. The growing season influenced the free sugar content, with generally higher levels in the spring/summer than in the summer/winter season in broccoli, while an opposite tendency was noted in the other Brassica species. In broccoli the sugar levels in the primary inflorescences were generally lower than in the secondary inflorescences, except for sucrose. © 2001 Society of Chemical Industry [source] Association of angiotensin-I converting enzyme DD genotype with influenza pneumonia in the elderlyGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2002Miyuki Onishi Background: Although angiotensin-I converting enzyme (ACE) is known to associate with cough reflex and inflammatory conditions, and both may participate in influenza pneumonia in the elderly, no study has been carried out on the association between influenza pneumonia and the insertion/deletion (I/D) polymorphism of the ACE gene (ACE). Methods: The subjects were 934 elderly inpatients (mean ± SD age of 82 ± 8 years) in a long-term care hospital. The association between ACE I/D and the incidence of influenza-pneumonia events was assessed over a winter season. Data were analyzed by multiple logistic regression analysis, with adjustment for age, gender, already known clinical risk factors, and ACE-inhibitor use. Results: During the follow-up period, 330 patients developed influenza (Directigen FLU-A) and 89 developed influenza pneumonia (Center for Disease Control and Prevention (CDC) criteria with chest X-ray required), 16 fatal and 73 non-fatal. Compared to non-influenza subjects (n = 604) and influenza patients without pneumonia (n = 241), ACE DD genotype (vs ID + II) resulted in a significant risk for all pneumonia (relative risk 2.32 [95% CI: 1.30,4.14] and 2.76 [1.39,4.04]), non-fatal pneumonia (1.91 [1.01,3.63] and 2.57 [1.23,5.39]) and fatal pneumonia (6.27 [1.68,23.3] and 5.15 [1.29,20.5]). Conclusion:ACE I/D polymorphism is a strong and independent risk indicator of influenza pneumonia events in elderly inpatients. [source] Seasonal snowpack dynamics and runoff in a cool temperate forest: lysimeter experiment in Niigata, JapanHYDROLOGICAL PROCESSES, Issue 20 2005Andrew C. Whitaker Abstract Seasonal snowpack dynamics are described through field measurements under contrasting canopy conditions for a mountainous catchment in the Japan Sea region. Microclimatic data, snow accumulation, albedo and lysimeter runoff are given through the complete winter season 2002,03 in (1) a mature cedar stand, (2) a larch stand, and (3) a regenerating cedar stand or opening. The accumulation and melt of seasonal snowpack strongly influences streamflow runoff during December to May, including winter baseflow, mid-winter melt, rain on snow, and diurnal peaks driven by radiation melt in spring. Lysimeter runoff at all sites is characterized by constant ground melt of 0·8,1·0 mm day,1. Rapid response to mid-winter melt or rainfall shows that the snowpack remains in a ripe or near-ripe condition throughout the snow-cover season. Hourly and daily lysimeter discharge was greatest during rain on snow (e.g. 7 mm h,1 and 53 mm day,1 on 17 December) with the majority of runoff due to rainfall passing through the snowpack as opposed to snowmelt. For both rain-on-snow and radiation melt events lysimeter discharge was generally greatest at the open site, although there were exceptions such as during interception melt events. During radiation melt instantaneous discharge was up to 4·0 times greater in the opening compared with the mature cedar, and 48 h discharge was up to 2·5 times greater. Perhaps characteristic of maritime climates, forest interception melt is shown to be important in addition to sublimation in reducing snow accumulation beneath dense canopies. While sublimation represents a loss from the catchment water balance, interception melt percolates through the snowpack and contributes to soil moisture during the winter season. Strong differences in microclimate and snowpack albedo persisted between cedar, larch and open sites, and it is suggested further work is needed to account for this in hydrological simulation models. Copyright © 2005 John Wiley & Sons, Ltd. [source] Suspended sediment transport regime in a debris-flow gully on Vancouver Island, British ColumbiaHYDROLOGICAL PROCESSES, Issue 4 2005Craig J. Nistor Abstract In debris-flow-prone channels, normal fluvial sediment transport occurs (nearly exclusively in suspended mode) between episodic debris-flow events. Observations of suspended sediment transport through a winter season in a steepland gully in logged terrain revealed two event types. When flows exceeded a threshold of 270 l s,1, events yielded significant quantities of sediment and suspended sediment concentration increased with flow. Smaller events were strongly ,supply limited'; sediment concentration decreased as flow increased. Overall, there is no consistent correlation between runoff and sediment yield. Within the season, three subseasons were identified (demarcated by periods of freezing weather) within which a pattern of fine sediment replenishment and evacuation occurred. Finally, a signature of fine sediment mobilization and exhaustion was observed within individual events. Fine sediment transport occurred in discrete pulses within storm periods, most of the yield occurring within 5 to 15% of storm runoff duration, so that it is unlikely that scheduled sampling programs would identify significant transport. Significant events are, however, generally forecastable on the basis of regional heavy rainfall warnings, providing a basis for targeted observations. Radiative snowmelt events and rain-on-snow remain difficult to forecast, since the projection of temperatures from the nearest regular weather station yields variable results. Copyright © 2004 John Wiley & Sons, Ltd. [source] Factors governing the formation and persistence of layers in a subalpine snowpackHYDROLOGICAL PROCESSES, Issue 7 2004David Gustafsson Abstract The layered structure of a snowpack has a great effect on several important physical processes, such as water movement, reflection of solar radiation or avalanche release. Our aim was to investigate what factors are most important with respect to the formation and persistence of distinct layers in a subalpine environment. We used a physically based numerical one-dimensional model to simulate the development of a snowpack on a subalpine meadow in central Switzerland during one winter season (1998,99). A thorough model validation was based on extensive measurement data including meteorological and snow physical parameters. The model simulated the snow water equivalent and the depth of the snowpack as well as the energy balance accurately. The observed strong layering of the snowpack, however, was not reproduced satisfactorily. In a sensitivity analysis, we tested different model options and parameter settings significant for the formation of snow layers. The neglection of effects of snow microstructure on the compaction rate, and the current description of the water redistribution inside the snowpack, which disregard capillary barrier effects, preferential flow and lateral water flow, were the major limitations for a more realistic simulation of the snowpack layering. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effects of the El Niño,southern oscillation on temperature, precipitation, snow water equivalent and resulting streamflow in the Upper Rio Grande river basinHYDROLOGICAL PROCESSES, Issue 6 2004Songweon Lee Abstract Snowmelt runoff dominates streamflow in the Upper Rio Grande (URG) basin of New Mexico and Colorado. Annual variations in streamflow timing and volume at most stations in the region are strongly influenced by the El Niño,southern oscillation (ENSO) through its modulation of the seasonal cycles of temperature and precipitation, and hence on snow accumulation and melting. After removing long-term trends over the study period (water years 1952,99), the dependence of monthly temperature, precipitation, snow water equivalent (SWE) at snowcourse stations, and streamflow throughout the URG on ENSO was investigated using composite analyses of the detrended residuals and through dependence of the residuals on the Climate Prediction Center southern oscillation index during the preceding summer and fall. The climate of La Niña years was found to differ significantly from either El Niño or neutral years. Moreover, significant climatological ENSO-related effects are confined to certain months, predominantly at the beginning and end of the winter season. In particular, March of La Niña years is significantly warmer and drier than during either El Niño or neutral years, and November of El Niño years is significantly colder and wetter. Differences in temperature and precipitation lead to significant differences in SWE and streamflow in the URG between the three ENSO phases. Copyright © 2004 John Wiley & Sons, Ltd. [source] Estimating winter evaporation in boreal forests with operational snow course dataHYDROLOGICAL PROCESSES, Issue 8 2003Angela Lundberg Abstract Snow course measurements from 11 sites located in eastern and northern Finland were used to estimate the total interception evaporation of a winter season for different forest categories. We categorized the sites based on forest density and tree species. Results showed that interception loss from gross precipitation increased with forest density and approached 30% for a forest with the highest density class. Interception loss for the most common forest density class was 11%. Interception losses were slightly larger in spruce forests than in pine, deciduous, or mixed forests. We provide suggestions as to how to design snow surveys to estimate wintertime interception evaporation better. Rough terrain and transition zones between forest and open areas should be avoided. Since evaporation fraction was strongly dependent on tree crown characteristics, snow course data should include direct estimates of canopy closure. Qualitative observations made by different observers should be given a reference frame to ensure comparability of records from different sites. Copyright © 2003 John Wiley & Sons, Ltd. [source] The North Atlantic Oscillation and European vegetation dynamicsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2008Célia Gouveia Abstract The relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over Europe. The study covers the 21-year period from 1982 to 2002 and is based on monthly composites of the Normalised Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC). A systematic analysis is first performed of point correlation fields over the 21-year period between the winter NAO index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of NDVI and comparing their behaviour for years associated with opposite NAO phases. Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high) vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined effect of warm conditions and water availability during the winter season. Copyright © 2008 Royal Meteorological Society [source] Identification of large scale climate patterns affecting snow variability in the eastern United StatesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2008Jennifer Morin Abstract This study investigates dominant patterns of snow variability and their relationship to large-scale climate circulations over the eastern half of the United States. Two snowfall variables,total seasonal snowfall (TSF) and number of snow days (NSD),are examined. A principal components (PC) analysis is conducted on data from 124 snowfall stations. The leading mode of variability for both TSF and NSD is driven by the North Atlantic Oscillation (NAO). The secondary mode of variability for TSF is driven by the Pacific/North American pattern (PNA), while the secondary mode of variability for NSD is driven by a dipole pattern and is attributable to regional influences and noise. These patterns exhibit persistence, which provides prospects for seasonal predictions of snowfall variables. This research compliments and extends the work of Serreze et al(1998), who performed a PC analysis of geopotential heights during the winter season and correlated the spatial patterns of the leading modes of variability with seasonal snowfall values. Copyright © 2007 Royal Meteorological Society [source] Interannual variability of the Tropical Atlantic independent of and associated with ENSO: Part II.INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2006The South Tropical Atlantic Abstract Two dominant ocean,atmosphere modes of variability on interannual timescales were defined in part I of this work, namely, the North Tropical Atlantic (NTA) and South Tropical Atlantic (STA) modes. In this paper we focus on the STA mode that covers the equatorial and sub-tropical South Atlantic. We show that STA events occurring in conjunction with ENSO have a preference for the southern summer season and seem to be forced by an atmospheric wave train emanating from the central tropical Pacific and travelling via South America, in addition to the more direct ENSO-induced change in the Walker Circulation. They are lagged by one season from the peak of ENSO. These events show little evidence for other-than-localised coupled ocean,atmosphere interaction. In contrast, STA events occurring in the absence of ENSO favour the southern winter season. They appear to be triggered by a Southern Hemisphere wave train emanating from the Pacific sector, and then exhibit features of a self-sustaining climate mode in the tropical Atlantic. The southward shift of the inter tropical convergence zone that occurs during the warm phase of such an event triggers an extra tropical wave train that propagates downstream in the Southern Hemisphere. We present a unified view of the NTA and STA modes through our observational analysis of the interannual tropical Atlantic variability. Copyright © 2006 Royal Meteorological Society. [source] Atmospheric circulation patterns related to heavy snowfall days in Andorra, PyreneesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2005Pere Esteban Abstract Heavy snowfalls over mountain regions are often a direct cause of avalanches. Specific synoptic-scale atmospheric situations are responsible for these kinds of extreme snowfall event, and this is indeed the case for Andorra, a small country located in the Pyrenees, between France and Spain. Based on days with an intensity of at least 30 cm of snow in a 24 h period, the present study uses principal component analysis (PCA) and clustering techniques to characterize the synoptic circulation patterns for these days during the winter season. The area of analysis encompasses the region 30,60°N by 30°W,15°E and the period covers the winter seasons from 1986,87 to 2000,01. The methodology proposed involves a preprocessing approach consisting of a spatial standardization of the data used for the PCA, an alternative approximation to decide the centroids and the number of groups for the K -means clustering, and the rejection of the iterations for this algorithm. This approach enables the synoptic classification of every heavy snowfall day, and composite maps were constructed for sea-level pressure, 500 hPa geopotential height, and 1000,500 m thickness (the 5270 m, 5400 m and 5520 m contour lines). The results show seven circulation patterns, most of them with an Atlantic component of the wind, and others with a clear Mediterranean advection that could be combined with cold continental air. The results, as weather charts, could be a useful tool to assist meteorological models in heavy snowfall forecasting, and the day's classification obtained opens up future possibilities for detailed meteorological and climatological analysis of the established types. Copyright © 2005 Royal Meteorological Society [source] A 10 year cloud climatology over Scandinavia derived from NOAA Advanced Very High Resolution Radiometer imageryINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 9 2003Karl-Göran Karlsson Abstract Results from a satellite-based method to compile regional cloud climatologies covering the Scandinavian region are presented. Systematic processing of multispectral image data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) instrument has been utilized to provide monthly cloud climatologies covering the period 1991,2000. Considerable local-scale variation of cloud amounts was found in the region. The inland Baltic Sea and adjacent land areas exhibited a large-amplitude annual cycle in cloudiness (high cloud amounts in winter, low cloud amounts in summer) whereas a weak-amplitude reversed annual cycle (high cloud amounts with a weak maximum in summer) was found for the Scandinavian mountain range. As a contrast, conditions over the Norwegian Sea showed high and almost unchanged cloud amounts during the course of the year. Some interesting exceptions to these patterns were also seen locally. The quality of the satellite-derived cloud climatology was examined through comparisons with climatologies derived from surface cloud observations, from the International Satellite Cloud Climatology Project (ISCCP) and from the European Centre for Medium-range Weather Forecasts ERA-40 data set. In general, cloud amount deviations from surface observations were smaller than 10% except for some individual winter months, when the separability between clouds and snow-covered cold land surfaces is often poor. The ISCCP data set showed a weaker annual cycle in cloudiness, generally caused by higher summer-time cloud amounts in the region. Very good agreement was found with the ERA-40 data set, especially for the summer season. However, ERA-40 showed higher cloud amounts than SCANDIA and ISCCP during the winter season. The derived cloud climatology is affected by errors due to temporal AVHRR sensor degradation, but they appear to be small for this particular study. The data set is proposed as a valuable data set for validation of cloud description in numerical weather prediction and regional climate simulation models. Copyright © 2003 Royal Meteorological Society [source] Long-term trends in near-surface flow over the BalticINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2003S. C. Pryor Abstract We report an analysis of trends in 850 hPa wind speed, as manifest in the NCEP,NCAR reanalysis fields, over the Baltic region during the latter half of the 20th century. The results indicate that annual mean wind speeds over the Baltic significantly increased over the period 1953,99 with the majority of the increase being associated with increases in the upper quartile of the wind speed distribution. Accordingly, much of the change is focused on the winter season. The trends in annual and seasonal mean wind speeds are greatest in relative and absolute sense in the southwest of the Baltic basin, where they are in excess of 0.25 m s,1 per decade for the annual mean. The extremes of the wind-speed distribution also increased by up to 5 m s,1 over the study period for the wind speed with a 50 year return period, again with the largest magnitude changes in the southwestern Baltic. These changes in wind speed are strongly linked to changes in the synoptic-scale circulation. The majority of the increase in wintertime wind speeds is attributable to an increase in westerly anticyclonic, westerly cyclonic and northwesterly cyclonic circulation types as manifest in the Grosswetterlagen catalogue, which are in turn related to the recent prevalence of the positive phase of the North Atlantic oscillation. Copyright © 2003 Royal Meteorological Society [source] Characteristics of wind variations on Jeju Island, KoreaINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2010Kyungnam Ko Abstract In order to clarify the long-term variability of the wind in complex terrain, an investigation was conducted on Jeju Island, Korea. The four coastal areas and the three mountainous areas were selected and wind data for 8,11 years from meteorological observatories were collected for this work. Inter-annual variations, monthly variations and diurnal variations in wind characteristics were calculated from the long-term wind data. As a result, it was found that wind speed is higher in the winter season while it is lower in the summer season. Wind at all sites blew strongly in the daytime and weakly at night. Also, wind energy and the range of variation in wind energy varied significantly from region to region on Jeju Island. Inter-annual variations in wind energy on Jeju Island occurred a little greater than seen in the results of earlier works conducted in other place. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sensitivity analysis of neural network parameters to improve the performance of electricity price forecastingINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2009Paras Mandal Abstract This paper presents a sensitivity analysis of neural network (NN) parameters to improve the performance of electricity price forecasting. The presented work is an extended version of previous works done by authors to integrate NN and similar days (SD) method for predicting electricity prices. Focus here is on sensitivity analysis of NN parameters while keeping the parameters same for SD to forecast day-ahead electricity prices in the PJM market. Sensitivity analysis of NN parameters include back-propagation learning set (BP-set), learning rate (,), momentum (,) and NN learning days (dNN). The SD parameters, i.e. time framework of SD (d=45 days) and number of selected similar price days (N=5) are kept constant for all the simulated cases. Forecasting performance is carried out by choosing two different days from each season of the year 2006 and for which, the NN parameters for the base case are considered as BP-set=500, ,=0.8, ,=0.1 and dNN=45 days. Sensitivity analysis has been carried out by changing the value of BP-set (500, 1000, 1500); , (0.6, 0.8, 1.0, 1.2), , (0.1, 0.2, 0.3) and dNN (15, 30, 45 and 60 days). The most favorable value of BP-set is first found out from the sensitivity analysis followed by that of , and ,, and based on which the best value of dNN is determined. Sensitivity analysis results demonstrate that the best value of mean absolute percentage error (MAPE) is obtained when BP-set=500, ,=0.8, ,=0.1 and dNN=60 days for winter season. For spring, summer and autumn, these values are 500, 0.6, 0.1 and 45 days, respectively. MAPE, forecast mean square error and mean absolute error of reasonably small value are obtained for the PJM data, which has correlation coefficient of determination (R2) of 0.7758 between load and electricity price. Numerical results show that forecasts generated by developed NN model based on the most favorable case are accurate and efficient. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effects of differences in diet and seasonal changes on the fatty acid composition in fillets from farmed and wild sea bream (Sparus aurata L.) and sea bass (Dicentrarchus labrax L.)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2008Mustafa Yildiz Summary The effects of dietary fatty acids and seasonal variation on the fatty acid profiles of farmed and wild sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) were determined by analysis of their fillets. Farmed sea bream and sea bass were fed on the same commercial feeds all year. Fatty acid profiles in the fillets reflected the fatty acid profiles of the commercial feeds. The predominant fatty acids in the trial feeds, fillets of farmed and wild sea bream and sea bass were 16:0, 18:1n -9, 18:2n -6, 20:5n -3 and 22:6n -3. The fatty acid profiles in the fillets of farmed sea bream and sea bass did not differ (P > 0.05) except in the winter season compared with those of their wild counterparts. However, the content of eicosapentaenoic acid (20:5n -3), docosahexaenoic acid (22:6n -3) in the fillets of the farmed and wild sea bass were significantly (P < 0.05) higher than the farmed and wild sea bream. The wild sea bream had significantly (P < 0.05) higher total saturated fatty acid and monounsaturated fatty acid (MUFA) levels, and lower total n -6 and n -3 polyunsaturated fatty acid (PUFA) levels in winter than in the summer and spring seasons. Similarly, in the fillets of wild sea bass, total n -3 PUFA levels were significantly (P < 0.05) lower, and the MUFA levels were higher in winter than in the other seasons. These results indicate that the farmed fish fillets were good sources of n -3 PUFA in each of the three seasons. However, wild fish were good sources of n -3 PUFA in the spring and summer. [source] ORIGINAL ARTICLE: Echinacea purpurea and Allium sativum as immunostimulants in fish culture using Nile tilapia (Oreochromis niloticus)JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5 2010S. M. Aly Summary The study was conducted to evaluate the efficiency of echnicacea (E) and garlic (G) supplemented diets as immunostimulant for tilapia (Oreochromis niloticus). Seven treatments were designed including a control (C). Fish were fed on 35% protein diet at a rate of 3% body weight per day. Echinacea (1.0 ppt) and garlic (3%) were incorporated in the feed, which was administered for periods of 1, 2 and 3 months (summer season), followed by basal diet for 4 more months (winter season). Neutrophil adherence and haematocrit values increased in both supplemented groups with prolonging period of application. The neutrophils adherence was significantly increased in all treatments except group administered echinacea for 1 month. The lymphocytic counts were significantly (p < 0.004) elevated that resulted in a significant increase in the total leucocytic count in groups administered echinacea for 1 and 2 months when compared with the control and/or other treatments. The gain in the body weight and specific growth rate was significantly increased in all supplemented groups (p < 0.004) during summer, but remained without any significant increase after winter. The survival rate was significantly high (>85%) in all the supplemented groups. The percentage of protection, after challenge infection using pathogenic Aeromonas hydrophila was the highest in groups supplemented with echinacea and garlic for 3 months after summer and winter seasons. It could be concluded that echinacea and garlic improve the gain in body weight, survival rate and resistance against challenge infection. Both compounds showed extended effects after withdrawal and improved resistance to cold stress during the winter season. However, a full commercial cost benefit analysis is necessary before recommending their application in aquaculture. [source] Impact of human coronavirus infections in otherwise healthy children who attended an emergency department,JOURNAL OF MEDICAL VIROLOGY, Issue 12 2006Susanna Esposito Abstract This prospective clinical and virological study of 2,060 otherwise healthy children aged <15 years of age (1,112 males; mean age,±,SD, 3.46,±,3.30 years) who attended the Emergency Department of Milan University's Institute of Pediatrics because of an acute disease excluding trauma during the winter season 2003,2004 was designed to compare the prevalence and clinical importance of human coronaviruses (HCoVs) in children. Real-time polymerase chain reaction (PCR) in nasopharyngeal aspirates revealed HCoV infection in 79 cases (3.8%): 33 HCoV-229E (1.6%), 13 HCoV-NL63 (0.6%), 11 HCoV-OC43 (0.5%), none HCoV-HKU1 genotype A, and 22 (1.1%) co-detections of a HCoV and another respiratory virus. The HCoVs were identified mainly in children with upper respiratory tract infection; there was no significant difference in clinical presentation between single HCoV infections and HCoV co-infections. Diagnostic methods were used in a limited number of patients, and the therapy prescribed and clinical outcomes were similar regardless of the viral strain. There were a few cases of other members of the households of HCoV-positive children falling ill during the 5,7 days following enrollment. These findings suggest that HCoV-229E and HCoV-OC43 have a limited clinical and socioeconomic impact on otherwise healthy children and their household contacts, and the HCoV-NL63 identified recently does not seem to be any different. The quantitative and qualitative role of HCoV-HKU1 genotype A is apparently very marginal. J. Med. Virol. 78:1609,1615, 2006. © 2006 Wiley-Liss, Inc. [source] Wheat field erosion rates and channel bottom sediment sources in an intensively cropped northeastern Oregon drainage basin,LAND DEGRADATION AND DEVELOPMENT, Issue 1 2004G. N. Nagle Abstract Sediment tracers were used to quantify erosion from cultivated fields and identify major source areas of channel bottom sediment within the Wildhorse Creek drainage, an intensively cropped tributary of the Umatilla River in northeastern Oregon, USA. Available data indicated that Wildhorse Creek was one of the largest sediment yielding tributaries of the Umatilla River. Carbon, nitrogen and the nuclear bomb-derived radionuclide 137Cs were used as tracers to fingerprint sediment sources. Sediment was collected from the stream bottom and active floodplain and compared to samples from cultivated fields and channel banks. Samples were characterized on the basis of tracer concentrations and a simple mixing model was used to estimate the relative portion of bottom sediment derived from cultivated surface and channel banks. The results indicate that the amount of bottom sediment derived from cultivated surface sources was less than 26,per,cent for the 1998 winter season, although this estimate has a high margin of error. Cesium-137 was also used to estimate surface erosion from three cultivated fields in the watershed. Annual estimates of erosion since 1963 from the three sampled fields were from 3 to 7,5,t,ha,1 yr,1. For the 1998 season, it appears that most channel-bottom sediment was of subsurface origin with much of it likely coming from channel and gully banks indicating that significant reductions in sediment in Wildhorse Creek might be accomplished by the stabilization of eroding riparian areas and swales on the lower slopes of agricultural fields. Published in 2004 by John Wiley & Sons, Ltd. [source] Influence of Temperature on the Liver Circadian Clock in the Ruin Lizard Podarcis siculaMICROSCOPY RESEARCH AND TECHNIQUE, Issue 7 2007Manuela Malatesta Abstract Reptiles represent an interesting animal model to investigate the influence of temperature on molecular circadian clocks. The ruin lizard Podarcis sicula lives in a continental climate and it is subjected to wide range of environmental temperatures during the course of the year. As consequence, ruin lizard daily activity pattern includes either the hibernation or periods of inactivity determined by hypothermia. Here we showed the rhythmic expression of two clock genes, lPer2 and lClock, in the liver of active lizards exposed to summer photo-thermoperiodic conditions. Interestingly, the exposition of lizards to hypothermic conditions, typical of winter season, induced a strong dampening of clock genes mRNA rhythmicity with a coincident decrease of levels. We also examined the qualitative and quantitative distribution of lPER2 and lCLOCK protein in different cellular compartments during the 24-h cycle. In the liver of active lizards both proteins showed a rhythmic expression profile in all cellular compartments. After 3 days at 6°C, some temporal fluctuations of the lCLOCK and lPER2 are still detectable, although, with some marked modifications in respect to the values detected in the liver of active lizards. Besides demonstrating the influence of low temperature on the lizard liver circadian oscillators, present results could provide new essential information for comparative studies on the influence of temperature on the circadian system across vertebrate classes. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source] Synchronized diapause termination of the peach twig borer Anarsia lineatella (Lepidoptera: Gelechiidae): Brownian motion with drift?PHYSIOLOGICAL ENTOMOLOGY, Issue 1 2010PETROS T. DAMOS The course of diapause development is studied for the first time for Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae) under field and laboratory conditions for three successive years (2005,2007) in northern Greece. Photoperiod has a significant influence on diapause termination and the mean number of days to pupation decreases progressively throughout the winter season. Cold storage, for at least 30 days at 4°C, results in a synchronized reactivation of the larvae, with the developmental time of larvae chilled for 45 and 60 days at 4°C becoming significantly shorter. A theoretical stochastic description of the effect of chilling on diapause termination is attempted. Larvae have discrete ,physiological stages' with different degrees of diapause intensity, and the insect passes through those stages with a probability distribution S(t) that evolves over time. This pattern of progressive transition is similar to Brownian motion and finally leads to a successfully synchronized diapause break in spring. Hence, A. lineatella overwinters in a weak diapause state and may complete diapause development in late January, although it shows synchronized termination in early February, after the experience of essential chilling. [source] Nocturnally retained zeaxanthin does not remain engaged in a state primed for energy dissipation during the summer in two Yucca species growing in the Mojave DesertPLANT CELL & ENVIRONMENT, Issue 1 2002D. H. Barker Abstract Differently oriented leaves of Yucca schidigera and Yucca brevifolia were characterized in the Mojave Desert with respect to photosystem II and xanthophyll cycle activity during three different seasons, including the hot and dry summer, the relatively cold winter, and the mild spring season. Photosynthetic utilization of a high percentage of the light absorbed in PSII was observed in all leaves only during the spring, whereas very high levels of photoprotective, thermal energy dissipation were employed both in the summer and the winter season in all exposed leaves of both species. Both during the summer and the winter season, when energy dissipation levels were high diurnally, xanthophyll cycle pools (relative to either Chl or other carotenoids) were higher relative to the spring, and a nocturnal retention of high levels of zeaxanthin and antheraxanthin (Z + A) occurred in all exposed leaves of both species. Although this nocturnal retention of Z + A was associated with nocturnal maintenance of a low PSII efficiency (Fv/Fm) on a cold winter night, pre-dawn Fv/Fm was high in (Z + A)-retaining leaves following a warm summer night. This indicates nocturnal engagement of Z + A in a state primed for energy dissipation throughout the cold winter night , while high levels of retained Z + A were not engaged for energy dissipation prior to sunrise on a warm summer morning. Possible mechanisms for a lack of sustained engagement of retained Z + A for energy dissipation at elevated temperatures are discussed. [source] Apoptotic Changes in the Epithelium Germinativum of the Cat (Felis catus s. domestica, L. 1758) at Different Ages and Breeding SeasonsREPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2008MJ SiemieniuchArticle first published online: 25 FEB 200 Contents Apoptosis (programmed cell death) could be considered as a physiological process that takes part in a healthy organism, which helps to maintain organism homeostasis. The visible deterioration of semen quality and the number of germ cells is accompanied by a seasonal decrease of the reproductive activity in some species. This post-effect cascade is caused by apoptosis, which is the primary mechanism responsible for the elimination of germ cells during spermatogenesis. The aim of our study was to assess apoptotic changes in the epithelium germinativum in cat testes at different ages. One hundred and two pairs of testes were obtained from domestic cats aged between 4 months and 10 years. The paraffin-embedded tissue sections were labelled using the Oncogene and Calbiochem Research Products DNA Fragmentation Detection Kit (Cat# QIA21; Darmstadt, Germany), which allows the recognition of apoptotic nuclei in tissue sections with Fragment End Labelling (FragELTM) of DNA. The activity of apoptotic processes in cat testes collected from the spring-summer period compared with the autumn-winter season revealed that, 59.42% and 51.51%, respectively, males testes were characterized by insignificant changes. The obtained data revealed a distinctive apoptotic changes in the young animal testes before spermatogenesis onset. An intensification of programmed death cells in the epithelium germinativum in the elder cats (between 3,6 and 6,10 years) was not observed. Apoptotic changes slightly intensified in cats aged between 12 and 36 months. [source] Variability of the North Atlantic eddy-driven jet streamTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 649 2010Tim Woollings Abstract Much of the atmospheric variability in the North Atlantic sector is associated with variations in the eddy-driven component of the zonal flow. Here we present a simple method to specifically diagnose this component of the flow using the low-level wind field (925,700 hpa ). We focus on the North Atlantic winter season in the ERA-40 reanalysis. Diagnostics of the latitude and speed of the eddy-driven jet stream are compared with conventional diagnostics of the North Atlantic Oscillation (NAO) and the East Atlantic (EA) pattern. This shows that the NAO and the EA both describe combined changes in the latitude and speed of the jet stream. It is therefore necessary, but not always sufficient, to consider both the NAO and the EA in identifying changes in the jet stream. The jet stream analysis suggests that there are three preferred latitudinal positions of the North Atlantic eddy-driven jet stream in winter. This result is in very good agreement with the application of a statistical mixture model to the two-dimensional state space defined by the NAO and the EA. These results are consistent with several other studies which identify four European/Atlantic regimes, comprising three jet stream patterns plus European blocking events. Copyright © 2010 Royal Meteorological Society [source] Southern hemisphere winter ozone fluctuationsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 572 2001P. K. Vigliarolo Abstract In this paper the relationship between ozone and atmospheric variability is explored over the southern hemisphere during the austral winter season, with special emphasis on synoptic transient fluctuations. The analysis of ozone tracks (or high-frequency ozone variability) shows that they have a significant correspondence with storm tracks at middle and high latitudes. Moreover, ozone tracks maximize over the Indian Ocean slightly downstream of the storm-track maximum, while over the Pacific region both ozone and storm tracks show decreased amplitudes. In particular, over southern South America (a region of climatological winter ozone minima and moderate to high ozone variability) the leading winter synoptic-scale variability mode was identified through a rotated extended empirical orthogonal function analysis applied to the meridional-wind perturbation at 300 hPa. The resulting mode is characterized by a baroclinic wave travelling eastward along subpolar latitudes, which maximizes near the tropopause level. Composite ozone fields based on this mode confirm, from a statistical point of view, the classical relationship between ridges (troughs) and minimum (maximum) ozone content. Furthermore, it is shown that dynamical processes in the upper troposphere and lower stratosphere associated with subpolar waves are responsible for the observed ozone distribution. This happens due to the barotropic equivalent vertical structure of the wave, together with the fact that ozone partial pressure maximizes near the level where the waves attain maximum amplitudes. [source] The seasonal forecast of electricity demand: a hierarchical Bayesian model with climatological weather generatorAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2006Sergio Pezzulli Abstract In this paper we focus on the one year ahead prediction of the electricity peak-demand daily trajectory during the winter season in Central England and Wales. We define a Bayesian hierarchical model for predicting the winter trajectories and present results based on the past observed weather. Thanks to the flexibility of the Bayesian approach, we are able to produce the marginal posterior distributions of all the predictands of interest. This is a fundamental progress with respect to the classical methods. The results are encouraging in both skill and representation of uncertainty. Further extensions are straightforward at least in principle. The main two of those consist in conditioning the weather generator model with respect to additional information like the knowledge of the first part of the winter and/or the seasonal weather forecast. Copyright © 2006 John Wiley & Sons, Ltd. [source] Surface water balance to evaluate the hydrological impacts of small instream diversions and application to the Russian River basin, California, USAAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2009Matthew J. Deitch 1.Small streams are increasingly under pressure to meet water needs associated with expanding human development, but the hydrologic and ecological effects are not commonly described in scientific literature. 2.To evaluate the potential effects that surface water abstraction can have on flow regime, scientists and resource managers require tools that compare abstraction to stream flow at ecologically relevant time scales. 3.The classic water balance model was adapted to evaluate how small instream diversions can affect catchment stream-flow; the adapted model maintains the basic mass balance concept, but limits the parameters and considers surface water data at an appropriate timescale. 4.This surface water balance was applied to 20 Russian River tributaries in north-central California to evaluate how recognized diversions can affect stream flow throughout the region. 5.The model indicates that existing diversions have little capacity to influence peak or base flows during the rainy winter season, but may reduce stream flow during spring by 20% in one-third of all the study streams; and have the potential to accelerate summer intermittence in 80% of the streams included in this study. 6.The surface water balance model may be especially useful for guiding river restoration from a hydrologic perspective: it can distinguish among streams with high diversion regimes that may require more than just physical channel restoration to provide ecological benefits, and can illustrate the extent to which changing the diversion parameters of particular water users can affect the persistence of a natural flow regime. 7.As applied to Russian River tributaries, the surface water balances suggest that reducing demand for stream flow in summer may be as important as physical channel restoration to restoring anadromous salmonids in this region. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effect of ENSO on the Hong Kong winter seasonATMOSPHERIC SCIENCE LETTERS, Issue 2 2009M. C. Wu Abstract The relationship between the ENSO condition and the winter condition in Hong Kong is investigated in this study. The winter monsoon over southern China tends to be weaker (stronger) during El Niño (La Niña) winters and Hong Kong tends to have higher (lower) mean winter temperatures against the background of the warming trend. On the other hand, there are more (fewer) surge events, which represents the southeastward advance of the Siberian cold air across the East Asian coast, affecting Hong Kong. Analyses showed that Hong Kong tends to be warmer with a shorter duration for the longest cold spell during the winter without blocking event over the Eurasian continent. Furthermore, blocking events are also less common during El Niño winters. Copyright © 2009 Royal Meteorological Society [source] Epidermal proliferative response induced by sodium dodecyl sulphate varies with environmental humidityBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2001M. Denda Background Previous studies have suggested that susceptibility of skin to external agents increases in the dry winter season. Objectives To test the hypothesis that environmental humidity affects skin sensitivity to irritants. Methods The epidermal hyperplasia induced by sodium dodecyl sulphate (SDS) under various humidity conditions was evaluated on the skin of hairless mice. Results Mice kept under low humidity for 2 days showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under high or normal humidity for 2 days. In contrast, mice kept under high humidity for 2 weeks showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under low or normal humidity. The transepidermal water loss was altered significantly in the animals kept under high humidity for 2 weeks, although it was not altered during the first 7 days under either low or high humidity. Conclusions These results suggest that environmental humidity influences the sensitivity of skin to topical application of SDS and that increased sensitivity is not always associated with alteration of the water impermeability of the stratum corneum. [source] | |||||||||||||||||||||||||