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PubMed2004

Bone mineral density of olympic-level female winter sport athletes.

PURPOSE: To compare areal bone mineral density (aBMD) of female winter sport athletes to healthy controls of similar age and body mass index (BMI). METHODS: Areal BMD (g x cm(-2)) of the whole body, lumbar spine (L2-L4), and right proximal femur were assessed by dual energy x-ray absorptiometry in athletes (N = 40; age: 26.1 +/- 5.7 yr; ht: 165.6 +/- 0.1 cm; wt: 63.0 +/- 6.5 kg; BMI: 23.0 +/- 1.9 kg x m(-2)) involved in speed skating (N = 9), snowboarding (N = 13), freestyle skiing (N = 3), biathlon (N = 8), bobsleigh, skeleton, luge (N = 7), and controls (N = 21; age: 26.0 +/- 5.1 yr; ht: 165.8 +/- 0.1 cm; wt: 62.8 +/- 5.9 kg; BMI: 22.9 +/- 1.3 kg x m(-2)). RESULTS: Using independent t-tests, athletes had lower fat mass, percent body fat, and higher lean mass than controls (P < 0.001). Areal BMD was higher in athletes than controls for all skeletal sites (P </= 0.007). With lean tissue mass as a covariate (ANCOVA), differences in aBMD remained significant for most skeletal sites (P </= 0.016). Menstrual history, mean daily calcium intake, and oral contraceptive use were not associated with aBMD in the athletic group. CONCLUSION: Results show that female winter sport athletes have greater aBMD compared with controls of similar age and BMI. Most aBMD differences remained significant after adjusting for lean tissue mass, and athletes with a history of oligo- and/or amenorrhea had similar aBMD than their eumenorrheic counterparts. This is the first study to examine aBMD in winter sport athletes. The results support the hypothesis that the loading characteristics of intense winter sport participation have osteogenic potential.

Adult↗
PubMed1986

Circadian rhythms of 6-sulphatoxy melatonin, cortisol and electrolyte excretion at the summer and winter solstices in normal men and women.

Urinary excretion of 6-sulphatoxy melatonin, cortisol, potassium and sodium was monitored at four hourly intervals for 24 h in 30 normal subjects at the summer and winter solstices. The 24 h profiles were fitted to sine curves and mean 24-h excretion, time of maximum excretion and amplitude of the curves compared. The excretion of 6-sulphatoxy melatonin was remarkably stable at the two times of the year (24-h excretion 108 +/- 6.3 nmol in summer and 105 +/- 6.3 nmol in winter, mean +/- SEM). The time of maximum excretion was significantly delayed in winter by 1 h and 40 min. Urinary cortisol excretion was significantly higher in winter, however, the amplitude was unaltered. The time of maximum excretion of cortisol was significantly delayed by 1 h and 34 min. Postassium and sodium excretion were both unaffected by seasonal influences. These results contrast with results in some animal species in which the duration of the melatonin signal is thought to be the key determinant in subsequent melatonin action. In humans it is likely that the phasing of the melatonin rhythm is of prime importance.

Adult↗
PubMed2000

Development and validation of a binomial sequential sampling plan for the greenbug (Homoptera: Aphididae) infesting winter wheat in the southern plains.

From 1997 to 1999, Schizaphis graminum (Rondani), intensity (number per tiller) was estimated on 115 occasions from hard red winter wheat fields located throughout the major wheat growing regions of Oklahoma. A total of 32 and 83 fields was sampled during the fall and spring, respectively. The parameters of linear regressions relating the mean number of greenbugs per tiller (m) and the proportion of infested tillers (PT) differed significantly between fall and spring infestations. The PT-m linear model provided a good fit for data on S. graminum for fall and spring infestations at tally thresholds of 0, 1, 2, and 3. A tally threshold (T) represents the number of greenbugs present on a tiller before the tiller is classified as infested by >T greenbugs. A regression model with a tally threshold of 2 was the most precise for classifying S. graminum populations during fall growth of winter wheat because it explained a greater amount of the variation in the PT-m relationship (97%) than models with other tally thresholds. A separate spring model with a tally threshold of 1 was the most precise for classifying S. graminum populations during spring growth of winter wheat. Sequential sampling stop lines based on sequential probability ratio tests were calculated for economic thresholds of 3 or 6 greenbugs per tiller for fall infestations and 6 or 9 greenbugs per tiller for spring infestations. With the newly developed parameters, the average sample number required to classify greenbug populations near economic thresholds (as above or below the economic threshold) varied from 69 to 207. We expect that the sampling plans for greenbugs in winter wheat developed during this study will be efficient and useful tools for consultants and producers in the southern plains.

Animals↗
PubMed2006

Temporal variability in winter travel patterns of Yellowstone bison: the effects of road grooming.

The influence of winter recreation on wildlife in Yellowstone National Park (YNP), Wyoming and Montana, USA, is a controversial issue. In particular, the effects of road grooming, done to facilitate snowmobile and snowcoach travel, on bison (Bison bison) ecology are under debate. We collected data during winters, from 1997 to 2005, on bison road use, off-road travel, and activity budgets to quantify temporal trends in the amount of bison road and off-road travel and to identify the ecological factors affecting bison movements and use of the groomed road system in the Madison-Gibbon-Firehole (MGF) area of YNP. Using model comparison techniques, we found bison travel patterns to be influenced by multiple, interacting effects. Road travel was negatively correlated with road grooming, and we found no evidence that bison preferentially used groomed roads during winter. Snow water equivalent, bison density, and the springtime melt period were positively correlated with both bison road and off-road travel. From behavioral scans on 68,791 bison, we found that travel is only a small percentage (11%) of all bison activity, with foraging comprising 67% of observations. Also, only 7% of traveling bison and 30% of foraging bison were displacing snow, and we suggest foraging, rather than traveling, is likely the major energetic cost to bison in winter. Bison utilize their own trail network, connecting foraging areas using stream corridors, geothermal pathways, and self-groomed travel routes. Our results indicate that temporal patterns in bison road travel are a manifestation of general travel behavior and that groomed roads in the MGF do not appear to be a major factor influencing bison ecology and spatial redistribution. We suggest that the changes in bison spatial dynamics during the past three decades have likely been the result of the natural phenomenon of density-dependent range expansion, rather than having been caused by the anthropogenic influence of road grooming.

Animals↗
PubMed2001

Effects of oral vitamin E supplementation during late gestation in beef cattle that calved in late winter and late summer.

OBJECTIVE: To determine effects of breed and oral vitamin E supplementation during late gestation on serum vitamin E and IgG concentrations in beef cows that calved in late winter and late summer and in neonatal calves. ANIMALS: 73 Angus and 43 Hereford primiparous and multiparous cows and their calves. PROCEDURE: Cows in groups that were homogeneous regarding breed and age distribution were randomly allotted to groups that were orally supplemented (n = 59) or not supplemented (57) with vitamin E beginning 30 days prior to onset of 65-day calving seasons. Supplemental vitamin E was provided in a vitamin-mineral mix offered free-choice until parturition. RESULTS: Cows that calved in late winter and were supplemented orally with vitamin E had higher serum vitamin E concentrations at calving and after calving than did unsupplemented cows; differences between groups before calving were not significant. Calves from supplemented multiparous cows had higher vitamin E concentrations than did calves from unsupplemented cows. Winter-born calves from supplemented Hereford cows had heavier 205-day adjusted weaning weights than did winter-born calves from unsupplemented Hereford cows. Supplementation did not affect vitamin E or IgG concentrations in the herd that calved in late summer and did not affect calf growth. CONCLUSIONS AND CLINICAL RELEVANCE: Oral vitamin E supplementation during late gestation may be economically beneficial in certain cow-calf operations in which late-gestation cows are consuming stored forages.

Animals↗
PubMed1995

Influence of energy or protein supplementation during midpregnancy on forage intake of ewes grazing Montana winter range.

A 2-yr winter experiment was conducted to determine the influence of either energy or protein supplementation during midpregnancy on fecal output (FO), forage intake, blood metabolite profiles, and BW changes of ewes grazing winter range. Thirty-two Targhee ewes were selected for uniformity in age and BW and assigned randomly to one of four dietary treatments 1) no supplement (NONE); 2) 150 g of barley supplement (BAR); 3) 75 of feather g meal, blood supplement (FM/BM); and 4) 75 g of FM, BM, urea supplement (FM/BU/U). Two 5-d experimental periods were conducted during each winter (January and February). Forage FO (P = 0.9), total FO (P = 0.7), and subsequent forage intake (P < .01) were higher during Yr 1 than during Yr 2. Supplement type did not affect forage DMI when expressed either as grams/day (P = .57) or as a percentage of BW (P = .52). Body weight changes and body condition scores were not affected (P > .10) by year but were affected (P < .01) by treatment; unsupplemented ewes lost more (P < .01) BW and body condition than supplemented ewes. Serum urea N (SUN) concentrations were affected (P < .03) by a year x treatment interaction. Unsupplemented, FM/ BM, and FM/BM/U ewes had higher (P < .10) SUN concentrations during Yr 1 than during Yr 2, averaging 9.8 ml/dL and 7.5 mg/dL, respectively. Barley-supplemented ewes had similar (P > .10) SUN concentrations both years, averaging 7.4 mg/dL. Alternate-day supplementation during midpregnancy with energy of protein had no effect on forage DMI of ewes grazing winter range.

Animal Feed↗
PubMed2004

Effect of live weight gain of steers during winter grazing: II. Visceral organ mass, cellularity, and oxygen consumption.

Two experiments were conducted to examine the effect of BW gain during winter grazing on mass, cellularity, and oxygen consumption of splanchnic tissues before and after the feedlot finishing phase. In each experiment, 48 fall-weaned Angus x Angus-Hereford steer calves were assigned randomly to one of three treatments: 1) high rate of BW gain grazing winter wheat (HGW), 2) low rate of BW gain grazing winter wheat (LGW), or 3) grazing dormant tallgrass native range supplemented with 0.91 kg/d of a 41% CP supplement (NR). At the end of winter grazing, four steers were selected randomly from each treatment for initial slaughter to measure organ mass, cellularity, and oxygen consumption. All remaining steers were placed into a feedlot and fed to the same backfat end point (1.27 cm). Six steers were selected randomly from each treatment for final organ mass, cellularity, and oxygen consumption. Initial empty BW (EBW) was greatest (P < 0.001) for HGW, intermediate for LGW, and least for NR steers in both Exp. 1 and 2 (355 > 263 > 207 +/- 6.5 kg and 337 > 274 > 205 +/- 8.7 kg, respectively). For both experiments, the initial total gastrointestinal tract (GIT; g/kg of EBW) proportional weight was greater (P < 0.05) in NR steers than in LGW, and LGW steers had greater (P < 0.05) initial GIT proportional weight than HGW steers. Proportional weight of total splanchnic tissues (TST; g/kg of EBW) did not differ (P < 0.19) among treatments. Initial duodenal RNA concentration and RNA:protein were greater (P < 0.02) in LGW than in HGW steers, and NR steers were intermediate. Initial in vitro liver O2 consumption was greater (P < 0.09) in HGW and LGW than in NR steers (34.5 > 16.9 mL/min), whereas initial small intestinal oxygen consumption was greater (P < 0.01) in LGW than in HGW and NR steers (12.1 > 5.2 mL/min). Ruminal papillae oxygen consumption did not differ (P < 0.55) among treatments. The rate of decrease of GIT (g x g EBW(-1) x d(-1)) during finishing was greater in NR than in HGW and LGW steers in both Exp. 1 and 2, but mesenteric fat (g x g EBW(-1) x d(-1)) increased for NR steers, resulting in a similar (P < 0.75) increase in TST across the finishing period for all treatments. Similar rates of increase in TST across the finishing phase corresponded with similar rates of live and carcass weight gain among treatments. Our data support the hypothesis that increased visceral organ mass increases maintenance energy requirements of growing cattle.

Animal Feed↗
PubMed1982

Simulated effect of calving season and winter hay feeding level on cow herd productivity.

The Texas A & M Cattle Production Systems Model was used to study herd productivity under several management plans open to cow-calf producers in the southeastern United States. An east Texas farm herd was simulated as a self-contained unit where all hay fed in the winter months was harvested from hay pastures or as surplus forage from grazed pastures. Management options examined involved (1) variation in the amount of forage fed as hay, and (2) spring vs fall calving. All forage was produced on well fertilized, intensively managed Coastal bermudagrass pastures. The winter feed options consisted of hay fed (1) ad libitum, and at (2) 80, (3) 60 and (4) 40% of the ad libitum level. The hay feeding period was November 15 through April 15. Overall herd productivity decreased as level of winter feeding decreased. Higher levels of hay feeding resulted in fewer cattle/unit land area but higher production/breeding cow. Herd size increased by 2.9, 11.9 and 32.5% as winter hay levels were reduced from ad libitum to 80, 60 and 40% of ad libitum, respectively, under spring calving management, whereas herd productivity measured as total live weight sold/herd (fixed land area) declined by 2.2, 9.4 and 10.3% with the respective feed levels. Spring-calving herds were approximately 3.2% larger in number than corresponding fall-calving herds on the same land area, but fall-calving herds produced an average of 3.6% more live weight sales.

Animal Husbandry↗
PubMed1983

Influence of body composition on energy requirements of beef cows during winter.

Twenty Angus-Hereford and 20 Angus-Holstein cows were individually fed 12.9 or 18.0 Mcal metabolizable energy (ME)/head daily from November 28, 1979 through February 21, 1980. Energy retentions for the winter feeding period were calculated by determining body composition at the initiation and at the termination of the feeding period. After the experimental period, all cows were managed the same through weaning. Maintenance energy requirements (Kcal/d) estimated from linear regressions of energy retentions on ME intakes per unit body weight (BW).75 were 127.6 and 140.3 kcal/BW.75 for Angus-Hereford and Angus-Holstein cows, respectively. Estimates of maintenance energy requirements for thin and fat cows within each breed type indicated that fatter cows of Angus-Hereford breeding had 6.1% lower energy requirements than thinner cows. Opposite trends occurred with Angus-Holstein cows, where fat cows had 2.7% higher maintenance requirements. Estimated maintenance energy requirements were higher (P less than .01) for protein than fat tissue. Maintenance energy requirements of fat was -1.55 kcal ME/kg for Angus-Hereford cows, indicating that for cows of the same lean body mass, cows with more fat have a lower daily energy requirement during winter. Angus-Holstein cows had an estimated maintenance energy requirement of fat of 51.11 kcal ME/kg. Because cattle of Holstein breeding have less subcutaneous fat than cattle of the beef breeds, and less subcutaneous fat would provide less insulation, the estimated maintenance requirements of fat in Angus-Holstein cows may be an estimate of the true maintenance requirement of fat. Estimates of the partial efficiency of ME use for tissue gain and the ME sparing effect of body tissue loss were 78.8% and .70, respectively, for Angus-Hereford cows and 53.8% and .46, respectively, for Angus-Holstein cows. Regression of retained energy on cow BW.75, body fat and body protein calculated for Angus-Hereford and Angus-Holstein cows from within energy level indicated that BW.75 accounted for less variation in retained energy than weight of empty body fat or protein. Multiple regressions that contained all three variables accounted for 75% and 32% of the variation for Angus-Hereford and Angus-Holstein cows, respectively. Subsequent performance of the cow and calf was not affected by winter energy levels fed, body composition of cows before calving or body energy changes of cows during the winter.

Adipose Tissue↗
PubMed1984

Induction of winter fur growth in mink (Mustela vison) with melatonin.

Adult and kit standard dark male and female mink were treated with 0, 5 or 10 mg melatonin, or a reduced photoperiod of 6 h light: 18 h dark (6L: 18D, initiated during the last week of June) to determine the effects of treatment on winter fur growth. Melatonin was administered in a Silastic implant inserted sc over the scapular region during the last week of June. Regardless of sex or age, mink treated with melatonin or a 6L: 18D photoperiod molted the summer pelage and grew the winter pelage earlier than controls (P less than .001). Winter pelage was fully prime by mid-October, 6 wk earlier than normal. Weight gain of mink, regardless of sex or age, was not affected by melatonin treatment. These findings indicate that photoperiodic effects on the growth of winter pelage in mink may be mediated through the pineal gland and its secretion of melatonin.

Animals↗
PubMed2004

Winter swimming improves general well-being.

OBJECTIVES: This study deals with the effects of regular winter swimming on the mood of the swimmers. METHODS: Profile of Mood State (POMS) and OIRE questionnaires were completed before (October) and after (January) the four-month winter swimming period. RESULTS: In the beginning, there were no significant differences in the mood states and subjective feelings between the swimmers and the controls. The swimmers had more diseases (about 50%) diagnosed by a physician. Tension, fatigue, memory and mood negative state points in the swimmers significantly decreased with the duration of the swimming period. After four months, the swimmers felt themselves to be more energetic, active and brisk than the controls. Vigour-activity scores were significantly greater (p < 0.05). All swimmers who suffered from rheumatism, fibromyalgia, or asthma, reported that winter swimming had relieved pains. CONCLUSION: Improvement of general well-being is thus a benefit induced by regular winter swimming.

Adult↗
PubMed1999

Incidence of plague associated with increased winter-spring precipitation in New Mexico.

Plague occurs episodically in many parts of the world, and some outbreaks appear to be related to increased abundance of rodents and other mammals that serve as hosts for vector fleas. Climate dynamics may influence the abundance of both fleas and mammals, thereby having an indirect effect on human plague incidence. An understanding of the relationship between climate and plague could be useful in predicting periods of increased risk of plague transmission. In this study, we used correlation analyses of 215 human cases of plague in relation to precipitation records from 1948 to 1996 in areas of New Mexico with history of human plague cases (38 cities, towns, and villages). We conducted analyses using 3 spatial scales: global (El Niño-Southern Oscillation Indices [SOI]); regional (pooled state-wide precipitation averages); and local (precipitation data from weather stations near plague case sites). We found that human plague cases in New Mexico occurred more frequently following winter-spring periods (October to May) with above-average precipitation (mean plague years = 113% of normal rain/ snowfall), resulting in 60% more cases of plague in humans following wet versus dry winter-spring periods. However, we obtained significant results at local level only; regional state-wide precipitation averages and SOI values exhibited no significant correlations to incidence of human plague cases. These results are consistent with our hypothesis of a trophic cascade in which increased winter-spring precipitation enhances small mammal food resource productivity (plants and insects), leading to an increase in the abundance of plague hosts. In addition, moister climate conditions may act to promote flea survival and reproduction, also enhancing plague transmission. Finally, the result that the number of human plague cases in New Mexico was positively associated with higher than normal winter-spring precipitation at a local scale can be used by physicians and public health personnel to identify and predict periods of increased risk of plague transmission to humans.

Animals↗
PubMed1999

Effects of immobilization with medetomidine and reversal with atipamezole on blood chemistry of semi-domesticated reindeer (Rangifer tarandus tarandus L.) in autumn and late winter.

Blood chemistry was studied in 8 adult female reindeer, of which 5 were pregnant. Half of them received only medetomidine (150 micrograms/kg i.m.) and half of them medetomidine and atipamezole (750 micrograms/kg) in March. Three weeks later the drug regimens were reversed. The same procedure was carried out during the next September and October. Seasonal differences in pretreatment values could be seen in serum urea, phosphorous, and cholesterol, with the highest concentrations during the autumn; and creatinine, ASAT, ALAT, and CK values, which were higher in the non-pregnant reindeer in late winter. Their low-protein and low-energy diet during the winter explains most of the differences. Increased enzyme activities in serum indicate decreased membrane stability of certain organs in late winter, possibly due to nutritional deficiencies. Treatment effects could be seen in several parameters. The increase in blood glucose and decrease in serum FFA were most probably due to alpha 2-adrenoceptor activation, which inhibits insulin release and lipolysis. These effects were partly or totally inhibited after treatment with the antagonist atipamezole. The earlier increase in serum CK and ASAT activities in those receiving atipamezole can be explained by increased tissue perfusion due to atipamezole itself and the fact that these animals stood up and began to move much earlier than did those which received medetomidine only. A significant decrease in serum Na+, K+, Cl-, Pi, cholesterol, total Ca, and total protein concentration observed during the first 10 to 40 min of the medetomidine sedation could be explained by possible haemodilution and diuresis. More effective metabolism of medetomidine in autumn could explain the shorter recovery times of reindeer receiving only medetomidine and most of the differences in treatment effects between the seasons: faster increase in protein and cholesterol concentrations after the decrease, and the antagonistic effect of atipamezole on glucose and Pi changes in autumn. Based on these results, medetomidine seems to be a good sedation agent for reindeer both in autumn and in late winter; the effects of medetomidine can be rather effectively antagonized by atipamezole.

Adrenergic alpha-Agonists↗
PubMed2000

Winter mortality in relation to climate.

We report further details of the Eurowinter survey of cold related mortalities and protective measures against cold in seven regions of Europe, and review these with other evidence on the relationship of winter mortality to climate. Data for the oldest subject group studied, aged 65-74, showed that in this vulnerable group, high levels of protection against indoor and outdoor cold at given outdoor temperatures were found mainly in countries with cold winters, and were associated with low levels of excess mortality at a given level of outdoor cold. Regions such as London that had poor protection against cold and/or high baseline mortalities had higher levels of winter excess mortality than expected for the coldness of their winters.

Aged↗
PubMed2001

The effect of winter sports participation on high school football players: strength, power, agility, and body composition.

In this study, football players (N = 57) in grades 9-11 from 3 high schools chose to participate in 1 of 2 groups. Group WC (N = 39) participated in off-season strength training only. Group SP (N = 18) participated in both a winter sport (either wrestling or basketball) and an identical strength training program. All participants were tested at the close of football season (Pre) and at the end of the winter sports season (Post), a period of 4 months. Body composition (weight [W] and body fat percentage [BF]), strength (calculated 1RM [1 repetition maximum] max for barbell bench press [BP] and squat [SQ]), power (vertical jump [VJ] and seated shot put [UP]), and agility (18.3-m agility run [AG]) were measured. Both groups WC and SP increased significantly in W and BF and improved significantly in BP and VJ (p < 0.05). Only the WC group improved significantly in SQ and AG (p < 0.05). Only the SP group increased significantly in UP (p < 0.05). Only the difference in SQ was statistically greater in the WC than in the SP group (p < 0.05). Regardless of winter activity, football players gain significant amounts of BF resulting in overall W increases. Football players participating in winter sports improved significantly in measurements of strength and power. There appears to be no clear advantage to devoting time solely to strength training.

Adolescent↗
PubMed2000

[Net photosynthetic rate of two species of wintering host mosses for gullaphids and its response to light, temperature and water content].

The net photosynthesis of Thuidium cymbifolium and Chrysocladium retrorsum, two species of wintering host mosses for gullaphids, and its response to light, temperature and water content were measured with CI-301PS(CID Inc. USA) both in winter and spring. The photosynthetic capacity of Thuidium cymbifolium and Chrysocladium retrorsum was about 141 and 117 mumolCO2kg-1dw.s-1, respectively, and trended to increase from winter to spring. The light saturation point of these two mosses at 800-900 mumol.m-2.s-1 was much higher than that of many other mosses, and the compensation point ranged from 40 to 50 mumol.m-2.s-1. The temperature response curves of these two mosses were similar, with optium temperature ranging from 25 to 36 degrees C in spring, and from 20 to 30 degrees C in winter. When the temperature was below the freezing point(-15 to 0 degree C), they both maintained a distinct net photosynthesis, with the optimum water content ranging from 200 to 300(400)% dw. The photosynthesis started to be restrained evidently, when the water content declined to about 150% dw. The gas exchange ceased or became negative, when the water content was as low as 40-50% dw. It can be inferred that these two species might be both poikilothermal and poikilohydric organisms, but the resistibility of T. cymbifolium to intense light and high temperature was higher than that of C. retrorsum.

Animals↗
PubMed2003

Plasma cholinesterase levels of mountain plovers (Charadrius montanus) wintering in central California, USA.

Declines of over 60% in mountain plover (Charadrius montanus) populations over the past 30 years have made it a species of concern throughout its current range and a proposed species for listing under the U.S. Endangered Species Act. Wintering mountain plovers spend considerable time on freshly plowed agricultural fields where they may potentially be exposed to anticholinesterase pesticides. Because of the population status and wintering ecology of plovers, the objectives of our study were to use nondestructive methods to report baseline plasma cholinesterase (ChE) levels in free-ranging mountain plovers wintering in California, USA, and to assess whether sampled birds showed signs of ChE inhibition related to anticholinesterase chemical exposure. We compared plasma ChE activity for mountain plovers sampled from the Carrizo Plain (an area relatively free of anticholinesterase pesticide use) with similar measures for plovers from the Central Valley (where anticholinesterase pesticides are widely used). Analyses for ChE inhibition indicated that none of the plovers had been recently exposed to these chemicals. However, mean ChE levels of plovers from the Central Valley were significantly higher (32%) than levels reported for plovers from the Carrizo Plain. This result differs from our original assumption of higher exposure risk to mountain plovers in the Central Valley but does suggest that some effect is occurring in the ChE activity of mountain plovers wintering in California.

Animals↗
PubMed2003

[Effects of sowing times on the spike differentiation of different wheat varieties under the climate of warm winter].

Spike differentiation processes and freezing damage of three wheat varieties were studied by sowing in different stages. The results showed that under the condition of weather changing warm, the time of entering each stage of spike differentiation of wheat of strong spring variety was earlier than that of wheat of spring variety and semi-winter variety. Sowing times had more effects on durative time of the elongation stage, single-prism stage and two-prism stage of the spike differentiation. Under sowing early, the stronger the springness of wheat was, the quicker it developed, the higher spike differentiation phases it reached before winter, and the more serious freezing damage it suffered in wintering. According to this, the semi-winter varieties of wheat should be adopted first and arranged in pairs with spring varieties in wheat production, and the sowing times should not be too early as the weather becoming warm.

Climate↗