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991.
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993.
Külli Hiiesaar Katrin Jõgar Ingrid H. Williams Anne Luik Eha Kruus Luule Metspalu 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(6):502-509
Before its establishment in Estonia at the beginning of the twenty-first century, the Colorado potato beetle Leptinotarsa decemlineata Say was a notifiable quarantine pest for many years. In high-latitude environments it encounters strong evolutionary pressure to adapt to low temperatures due to high overwintering mortality and periodic influx of new individuals from more southern populations. Our study focused on gathering evidence for such a range shift leading to the formation of a permanent local population. The phenology and overwintering success of beetles was investigated from 2008 to 2015. Depending on weather conditions in the different years, the overwintered beetles emerged from the soil from the beginning of May to mid-June. Over 700 degree days accumulated in 2010, 2011, 2013 and 2014 exceeding the limit needed for development of two generations. However, food supply and temperature distribution in the growing period enabled development of the second complete generation only in 2010 and 2013. Survival of overwintering beetles in field conditions varied between 18% and 47% in the different years. Winter mortality was not associated with low air temperature in any year as snow cover provided the necessary protection and winter soil temperatures at the depth of 30?cm remained at around 0°C for the duration of the whole observation period, with only some records as low as ?3.5°C. The survival of overwintering beetles is more likely defined by factors other than low temperature. As a result of periodic invasions of beetles with naturally lower cold resistance originating from southern regions, the structure of the overwintering population in Nordic temperate conditions is not homogeneous. Moreover, this may also be derived from cultural practices, as commercial producers regularly apply agrochemicals while organic growers avoid them. 相似文献
994.
Kuczynski LA Schwartz P Peddle G Huang S Mai W Giger U 《Journal of the American Animal Hospital Association》2012,48(4):278-283
At approximately 4-5 mo of age, three Polish Lowland sheepdog puppies from a single litter of eight puppies presented to their respective primary veterinarians with bilateral subcutaneous masses in their ventral cervical regions. Evaluation, including thyroid function testing, surgical exploration with resection, computed tomography, and angiography, identified the masses as enlarged thyroid glands with severely dilated and abnormal vasculature in the regions of the glands. The dogs were also found to have serum concentrations of thyroid hormones that were below the reference ranges. None of the three dogs showed clinical signs of hypothyroidism, except for the presence of goiter. One dog also had a patent ductus arteriosus that was surgically repaired. All dogs were clinically normal at 2 yr of age. This is the first report of major vascular anomalies associated with goiter in any species. The mechanism is unknown. 相似文献
995.
Maryline Pellerin Anne Delestrade Gwladys Mathieu Olivier Rigault Nigel G. Yoccoz 《European Journal of Forest Research》2012,131(6):1957-1965
A participatory network was set up to study tree phenology in the Western Alps. We used data collected in 2006 and 2007 on birch, ash, hazel, spruce and larch to assess how local air temperature, altitude and other topographic variables influenced dates of budburst and leaf unfolding. Altitude was, as expected, a main predictor variable of budburst and leafing dates with delays ranging from 2.4 to 3.4 days per 100 m. Ash was the only species with strong evidence of a year difference in the altitudinal gradient with the warm year (2007) characterized by a weaker altitudinal gradient. We found a latitudinal gradient in the appearance of budburst for one coniferous species (larch) and curvature affected leafing in ash. Thermal sum (sum of Degree-Days above 0 °C) was increasing with altitude for budburst (birch, ash and larch) and leafing (birch and ash). Understanding of altitude and topography effects in addition to temperature in phenological models should improve projections of future changes in mountain regions. 相似文献
996.
Predicted future changes in air temperature and atmospheric CO(2) concentration ([CO(2)]), coupled with altered precipitation, are expected to substantially affect tree growth. Effects on growth may vary considerably across a species range, as temperatures vary from sub-optimal to supra-optimal for growth. We performed an experiment simultaneously at two locations in the current range of loblolly pine, a cool site and a warm site, to examine the effect of future climate conditions on growth of loblolly pine seedlings in contrasting regions of the species range. At both sites 1-year-old loblolly pine seedlings were grown in current (local ambient temperature and [CO(2)]) and predicted future atmospheric conditions (ambient +2 °C temperature and 700 μmol mol(-1) [CO(2)]). Additionally, high and low soil moisture treatments were applied within each atmospheric treatment at each site by altering the amount of water provided to the seedlings. Averaged across water treatments, photosynthesis (A(net)) was 31% greater at the cool site and 34% greater at the warm site in elevated temperature and [CO(2)] compared with ambient temperature. Biomass accumulation was also stimulated by 38% at the cool site and by 24% at the warm site in that treatment. These results suggest that a temperature increase of 2 °C coupled with an increase in [CO(2)] (predicted future climate) will create conditions favorable for growth of this species. Reduced soil moisture decreased growth in both current and predicted atmospheric conditions. Biomass accumulation and A(net) were reduced by ~39 and 17%, respectively, in the low water treatment. These results suggest that any benefit of future atmospheric conditions may be negated if soil moisture is reduced by altered precipitation patterns. 相似文献
997.
998.
Brian Wilcock Anne Wilcock Katherine Bottoms 《The Canadian veterinary journal. La revue veterinaire canadienne》2012,53(4):430-434
Comparison of the annual prevalence of feline postvaccinal sarcomas among 11 609 feline skin mass submissions from 1992 to 2010 revealed no decrease in disease prevalence or increase in the age of affected cats in response to changes in vaccine formulation or recommended changes in feline vaccination protocols. 相似文献
999.
1000.
Anne Fawcett 《The Journal of small animal practice》2012,53(8):489-489