Wild bird movements and aggregations following spells of cold weather may have resulted in the spread of highly pathogenic avian influenza virus (HPAIV) H5N1 in Europe during the winter of 2005-2006. Waterbirds are constrained in winter to areas where bodies of water remain unfrozen in order to feed. On the one hand, waterbirds may choose to winter as close as possible to their breeding grounds...

this paper modeled heating air of a room through examining free convection in a 3d chamber. the chamber had cold and hot sources with tc and th temperatures, respectively. its other walls were adiabatic. this study aimed at predicting effect of temperature difference, displacement of hot and cold sources and their aspect ratio on flow field, temperature and heat transfer rate. to conduct the st...

abstract in this experiment the effects of two type of medium cultures, gibberellic acid and dark/cold and light/warm culture conditions on mature embryos germination of a local cultivar of walnut were investigated. the mature fruits were collected at 22 weeks postanthesis and after disinfection the mature embryo along with cotyledon pieces were excised and then were cultured on mt and modified...

aims: tehran’s uncontrolled expansion, which promoted housing, public utilities, industries and increase of vehicles caused the problem of air pollution. necessary information about air quality in different places and different times is the first step of combating the air pollution. the purpose of this study was to investigate the annual, monthly and hourly average of 5 criteria air pollutants ...

Temperature reduction in early spring, especially corporate with buds swelling, sometimes causes severe damages. Most of the fruit trees in tropical and semi-tropical regions, especially in more critical conditions, moderate, at early spring are subjected to the frostbite and winter cold injuries. This study aimed to evaluate the amount of proline, total protein, and soluble sugars during the p...

cold tolerance is an adaptative mechanism that plants in temperate climates require to survive and grow in suboptimal temperatures.  exposed plant to low temperature produces a myriad of measurable changes in biochemical characters that are often highly correlated with plant cold tolerance.  a key element of cereal adaptation to cold is represented by the capacity for physiological adjustments ...

Background -Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels has been experimentally demonstrated. Extensive genetic variation has also been observed among hybrids in the field. However, what makes a certain hybridization event of evolutionary importance is...

The mechanisms underlying the occurrence of temperature extremes in Iberia are analysed considering a Lagrangian perspective of the atmospheric flow, using 6-hourly ERA-Interim reanalysis data for the years 1979 2012. Daily 2-m minimum temperatures below the 1st percentile and 2-m maximum temperatures above the 99th percentile at each grid point over Iberia are selected separately for winter an...

This study evaluates simulations of the East Asian winter monsoon in eight GCMs that participated in the Atmospheric Model Intercomparison Project (AMIP). In addition to validating the mean state of the winter monsoon, the cold surge and its transient properties, which includes the frequency, intensity, preferred propagation tracks, and the evolution patterns of the surges, are examined. GCM si...

nowadays, one of the greatest energy consumption sources in the world is recognized as hvac systems, which are used vastly not only for industrial productions but also for creating comfort condition in dwellings. since beginning of warm or cold season, we will need a source of energy to reach desirable thermal conditions inside a building. also, earth is naturally a great thermal source, which ...