Impacts of climate change on development rate and production of corn in the northeastern China

In this paper, the impacts of climate change on development rate and production of corn in the northeastern China are discussed. The results show that the higher the temperature is, the faster the development rate will be. And the more the precipitation is, the slower the development rate will be. Of which, air temperature is the controlling factor of corn development rate. The influences of development rate on corn yield are remarkable. The impacts of development rate on production in first and last periods are great, and small in the middle two periods. The development rate is positive by relate with corn production from sowing to emergence stage and negative during other periods. So, it is very important to arrange a suitable sowing time for com cultivating in the northeastern China.

Effect of different stretching strategies on the kinetics of vertical jumping in female volleyball athletes

Purpose： The present study aimed to examine the effect of static stretching （SS） and a sport-specific dynamic stretching （DS） session at two specific post-stretch time intervals in highly trained female athletes （age 19.90 ± 1.60 years; height 1.80 ±0.06 m; mass 76.87 ± 9.95 kg） on kinetic parameters of peak force, time-to-takeoff, and rate of force development. Methods： The data were collected over 3 days （randomized within subject design with control session）. Following each stretch session （SS vs. DS vs. control） of equal duration （7 min total： 30 s per targeted muscle group） participants performed countermovement jumping on a force platform at 1 and 15 rain after stretching. Results： The DS session significantly improved upon kinetic variables of rate of force development, peak force, and time-to-takeoffrelative to SS at 1 min after stretching. No significant effect was found at 15 min. Conclusion： Together these findings suggest that when training and competing to jump quickly and maximally the female athlete should incorporate DS instead of SS as part of their pre-competition warm-up, but conduct performance within 15 min of their warm-up to elicit maximal gains

Development rate of Labidocera euchaeta Giesbrecht in Xiamen Harbor

-The development rate of Labidocera euchaeta Giesbrecht in the Xiamen Harbor was studied in laboratory. The results showed that the development times of egg and larval stages ( D ) were significantly correlated with temperature ( T ), following the Belehradek function, D = α( T -7. 5)-1.0634. The development time from egg to larval stages and adult, as well as generation time can be predicted from the equation for egg development ( α=411/24) by appropriately multipling the constant (α) with a proportion. The development was not isochronal over the whole larval period. Durations of naupliar stages were short and quasi-isochronal, which favored their non-feeding development. In contrast, durations of copepodid stages (C) were long. CV had the longest duration followed by CI, both of which are considered as the critical stages in the larval development. The acclimation effect of the seasonal temperature on the development rate was also observed.

Effect of Strain Rate on Compression Behavior of Vinyl Ester Resin Casting

Quasi-static and high strain rate compressive experiments on vinyl ester casting were carried out by means of MTS (Material Test System) and Hopkinson bar. The behaviors of the compressed unstable and fracture of the resin casting at different strain rates were investigated.The results indicate that the response behavior of the resin casting is controlled by different mechanisms at different strain rate, and some mechanical properties of vinyl ester casting are rate-dependent: the casting are destroyed in toughness model under strain rate 3.3×10 -4～6.6×10 -3/s, while the casting are destroyed in brittleness model under strain rate 950～5800/s. The yield stress, yield strain energy density are all increased with the increasing strain rates at quasi-static as well as at high strain rates. What is interesting is that the yield strain decreased with the strain rates increasing at quasi-static while increased at high strain rates. It is considered that the casting occurred forcing high elastic deformation at high strain rates. The damage of the specimens is mainly controlled by axial stress before unstable deformation, while mainly controlled by shear stress after unstable deformation, and then developed to fracture finally. This progress is rate-dependent: the development of the cracks inside the castings increased with the strain rate increasing.

Development of Heart Rate Variaty in the Early and Rehabilitation Phase of AMI

Heart rate variaty (HRV) of 85cases with AMI was observed in the early phase after onset and rehabilitation phase at first month and sixth month, and was contrasted with six time threshold indices of 111 cases with coronary heart disease and that of 35 normal control. We found the HRV of AMI was apperantly lower in the acute phase than that of coronary heart disease and normal controls. HRV recovered gradually with inclining to be stable after half a year, but it was still lower than that of controls. Low HRV in early phase of AMI suggested the poor prognosis.

Sport specificity background affects the principal component structure of vertical squat jump performance of young adult female athletes

Purpose： Long-term training specificity is thought to alter performance in tests evaluating strength and power production capability. The aim of the present study was to provide additional information to the limited existing knowledge concerning the possible differences of the force/time profile of squat jumping among different groups of young female athletes. Methods： One hundred and seventy-three adult women （20.1 ± 2.8 years, 1.71 ± 0.09 m, 65.6 ± 10.3 kg, mean± SD for age, height, and mass, respectively） engaged in track and field （TF）, volleyball （VO）, handball （HA）, basketball （BA）, and physical education students （PE） executed maximal squat jumps （SQJ） on a force plate. Pearson＇s correlation was used to identify the relationship between SQJ performance, the anthropometric characteristics and the biomechanical parameters. Differences concerning the biomechanical parameters among groups were investigated with analysis of variance, while the force- （FPD） or time- （TPD） dependency of SQJ execution was examined using principal components analysis （PCA）. Results： SQJ was unrelated to body height but significantly correlated with body mass （r = -0.26, p = 0.001）. TF jumped higher and produced larger peak body power output compared to all the other groups （p 〈 0.05）. All athletes were superior to PE since they performed the SQJ with a longer （p 〈 0.05） vertical body center of mass trajectory during the propulsion phase. PCA results revealed that TF significantly differentiated than the other groups by relying on FPD. Conclusion： Various different profiles of FPD and TPD were detected due to different sporting background in young female athletes. Since TF superiority in SQJ was relied on the larger power production and a greater FPD, female indoor team sport athletes are suggested to execute jumping exercises adopting the jumping strategies utilized by TE

Impacts of climate change on wheat development and production in the northern China

In this paper, impacts of climate change on wheat development rate and production in the northern China are discussed. The results show that the temperature is a controlling factor of development rate but the precipitation is not. The higher the temperature is. the faster the development and the shorter development period will be. Without consideration to varieties and cropping system, meteorological yield of winter wheat would decrease 170.40, 134.25, 98.70 and 97.20 kg/hm2 in the north China and 13.97, 7.95, 39.60 and 19.80 kg/hm2 in the northwest China compared with that in 1950s, 1960s, 1970s and 1980s, respectively, when the CO2 concentration in the atmosphere is doubled. In drought and semi-drought regions, the spring wheat yield would drop with the temperature rise in and raise with the precipitation increase. The influence of temperature on weight of leaf and stalk is also remarkable.

Effects of Bovine Embryos at Different Developmental Stages on Bisection Effect

[Objectives]This study was conducted to explore the effects of embryos at different developmental stages on the bisection effect of embryos,improve the efficiency of bovine embryo bisection,and facilitate the application of embryo bisection technology in cattle breeding.[Methods]The effects of two different bisection solutions on the bisection of morulae and blastocysts in vitro were explored.The morulae and blastocysts produced in vitro from cattle that developed to the 6th to 8th d were bisected by hands,and demi-embryos were cultured in vitro.Their development was observed.[Results]Morulae were bisected in PBS solution and PBS+0.2 mol/L sucrose,and the success rates of bisection were 50%and 95.2%,respectively.The success rate of bisecting morulae in PBS+0.2 mol/L sucrose was significantly higher than that in PBS(P<0.05),while the development rate of the bisected demi-embryos had no significant difference between the two(53.3%,52.4%)(P>0.05).The success rates of blastocyst bisection in PBS solution and PBS+0.2 mol/L sucrose were 51.6%and 95.1%,respectively.The success rate of blastocyst bisection in PBS+0.2 mol/L sucrose was significantly higher than that in PBS(P<0.05),while the development rate of the bisected demi-embryos had no significant difference between the two(50.0%,56.4%)(P>0.05).[Conclusions]There were no significant differences between the success rates of bisecting bovine morulae and blastocysts in PBS+0.2 mol/L sucrose,which were both significantly better than those in pure PBS bisection solution,proving that PBS+0.2 mol/L sucrose bisection solution is suitable for bovine embryo bisection.

Research on Key Technology of Efficient Production of Bovine Embryos

[Objectives]This study was conducted to explore the effects of three different splitting fluids on the bisection effects of bovine morulae and blastocysts.[Methods]With the help of a micromanipulator,the morulae and blastocysts that were routinely produced in the body from the 6 th to the 8 th d were divided into half-embryos in vitro to observe their development,and the half-embryos with a restored morphology and a blastocyst trophoblast were selected.[Results]The success rates of bisection of morulae in PBS+0.2 mol/L sucrose and PBS+5%PVP were significantly higher than that in PBS(P<0.05),and the values in the three liquids were 95.7%,97.2% and 50%,respectively,while the blastocyst development rates and of half-embryos and the pregnancy rates of transplantation were not significantly different(P>0.05).When blastocysts were bisected in PBS+0.2 mol/L sucrose and PBS+5% PVP,the success rates of bisection were significantly higher than that of PBS(P<0.05),and the values in the three liquids were 96.8%,95.5% and 50.0%,respectively,while the development rates of half-embryos and the pregnancy rates of transplantation were not significantly different(P>0.05).The development rate of half-embryos bisected from blastocysts was significantly higher than that of morulae.[Conclusions]This study improves the efficiency of bovine embryo bisection,which is beneficial to the application of embryo bisection technology in cattle breeding.

Peak Torque as an Indicator of Rapid Torque Production during Screening Examinations

Although the ability to produce force rapidly is an indispensable characteristic of optimal health and performance, screening for this very critical parameter of strength is difficult because of clinician time constraints. The purpose this study was to investigate relationships between peak torque （PT） and rate of torque development （RTD） at 0-30, 0-50, 0-100, and 0-200 ms in female collegiate soccer athletes. Seventeen female collegiate soccer athletes were recruited. Isometric PT and RTD were collected at the hip abductors （AB）, hip adductors （AD）, knee extensors （KE） and knee flexors （KF）. The coefficients of determination were calculated to evaluate the association between PT and RTD. Normalized AB, AD and KF PT were significantly correlated to RTD at 0-30, 0-50, 0-100 and 0-200 ms, while KEPT was only significantly correlated to RTD at 0-100 and 0-200 ms. The results of this study indicate that PT is a viable, indirect indicator of early late phase RTD at separate time intervals at the AB, AD and KF. However, it is likely that other physiological factors coupled with PT are required to provide information on the rapid force production capabilities of the KFs and KEs based on the percent of common variance observed.

Force Distribution Model of Motor Units of Leg Extensor Muscles

The paper aims to defme the lawfulness （model）, by which one can reliably estimate the distribution of motor units＇ force from the moment when leg extensor muscles start to generate the force until the moment when the maximal level is achieved. The study included 110 participants. To assess the contractile characteristics of leg extensors, standardized equipment and standardized isometric test in sitting position with the angle of the knee joint of 125° were used. The participants were instructed to exert their maximal force as quickly as possible. Using descriptive statistics, cluster analysis and fitting the exponential model of the distribution of force of leg extensor motor units in the whole range of force generation is defined. The model has the following form： y = 0.2051e3.3855x, where y is the motor units force expressed in daN （decanewtons）, x is the time expressed in s （seconds）. It provides an understanding of the control of multivariate motor unit recruitment and distribution of their force during sports movements as well as training programming for the adoption of forms for conlrolling force distribution of motor units, the development of their maximum force and their involvement speed.

Development rate and lower temperature threshold in the eggs of Eurygaster integriceps （Heteroptera： Scutelleridae）

The sunn pest, Eurygaster integriceps Put. has a wide distribution in the Palearctic region. It is the most important pest problem of wheat in Turkey. The objective of this study was to attain better knowledge of the development of the sunn pest eggs. The lower temperature threshold and development rate of eggs were determined at 17, 20, 23, 26 and 32℃ ±1℃ in the laboratory. A linear model was used to describe the developmental rate and temperature. The egg development required 90.9 degree-days above the theoretical threshold of 11.7℃. The development time was 17.6 ±0.1 days at 17℃, and 4.5±0.01 days at 32 ℃. Incubation time was inversely related to temperature. The study showed that the eggs of E. integriceps needed shorter periods of time to complete their development than immature stages of their parasitoids Trissolcus spp.

Temperature-dependent development of diamondback moth, Plutella xylostella （Lepidoptera： Plutellidae） on two brassicaceous host plants

The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative humidity of 65% and a photoperiod of 14：10 （L： D） hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage, Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃ and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.

Effect of temperature on the Bulinus globosus-Schistosoma haematobium system

Background:Given that increase in temperature may alter host-parasite relationships,the anticipated rise in temperature due to global warming might change transmission patterns of certain diseases.However,the extent to which this will happen is not well understood.Methods:Using a host-parasite system involving Bulinus globosus and Schistosoma haematobium,we assessed the effect of temperature on snail fecundity,growth,survival and parasite development under laboratory conditions.Results:Our results show that temperature may have a non-linear effect on snail fecundity and snail growth.Snails maintained at 15.5℃ and 36.0℃ did not produce egg masses while those maintained at 25.8℃ laid 344 and 105 more egg masses than snails at 31.0℃ and 21.2℃,respectively.Attainment of patency led to a reduction in egg mass production among the snails.However,the reduction in fecundity for snails maintained at 21.2℃ occurred before snails started shedding cercariae.Parasite development was accelerated at high temperatures with snails maintained at 31.0℃ reaching patency after three weeks.Furthermore,snail growth rate was highest at 25.8℃ while it was inhibited at 15.5℃ and reduced at 31.0℃.Increase in temperature increased snail mortality rates.Snails maintained at 36.0℃ had the shortest survival time while those maintained at 15.5℃ had the longest survival time.Conclusions:We concluded that temperature influences fecunxdity,growth,survival and parasite development in the snail and thus dictates the time it takes the parasite to complete the life cycle.This has implications on transmission of schistosomiasis in the context of global warming.

Confidence interval of intrinsic optimum temperature estimated using thermodynamic SSI model

The intrinsic optimum temperature for the development of ectotherms is one of the most important factors not only for their physiological processes but also for ecolog- ical and evolutional processes. The Sharpe-Schoolfield-Ikemoto （SSI） model succeeded in defining the temperature that can thermodynamically meet the condition that at a par- ticular temperature the probability of an active enzyme reaching its maximum activity is realized. Previously, an algorithm was developed by Ikemoto （Tropical malaria does not mean hot environments. Journal of Medical Entomology, 45, 963-969） to estimate model parameters, but that program was computationally very time consuming. Now, investi- gators can use the SSI model more easily because a full automatic computer program was designed by Shi et al. （A modified program for estimating the parameters of the SSI model. Environmental Entomology, 40, 462-469）. However, the statistical significance of the point estimate of the intrinsic optimum temperature for each ectotherm has not yet been determined. Here, we provided a new method for calculating the confidence interval of the estimated intrinsic optimum temperature by modifying the approximate bootstrap confidence intervals method. For this purpose, it was necessary to develop a new program for a faster estimation of the parameters in the SSI model, which we have also done.

Inter-Individual Rapid Force Improvements after Mixed Session and Traditional Periodization in Aging Adults:A Randomized Trial

Background Different periodization models have been widely used to improve maximum and rapid force in aging adults.However,it is unclear if some specific model can influence the remarkable heterogeneity of responsiveness to rapid torque improvements following resistance training.Aims Compare the effects of mixed session periodization(MSP)and traditional(TP)models on neuromuscular performance and individual responsiveness in aging adults.Methods Twenty-two aging men and women(64.6±5.2 years old;1.68±0.1 m;77.8±16.0 kg)completed the intervention period.They were assigned into MSP(n=11)or TP(n=11)resistance training for lower limbs.The outcome measures normalized dynamic leg press(5-RM:BM),absolute and normalized knee isometric peak torque(PT and PT:BM)and rate of torque development,and impulse were assessed at baseline and after three blocks of a 9-wk resistance training(3 sessions per week).Thigh leg lean mass was assessed by dual-energy x-ray absorptiometry at baseline and after the intervention.Results Similar increases were observed for 5-RM:BM(MSP:28.8%±13.5%and TP:26.4%±7.6%,P<0.001),PT(MSP:223.7±50.7 N·m and TP:189.9±58.6 N·m,P<0.001),but it was not observed for PT:BM(MSP:16.4%±16.5%and TP:4.7%±9.2%,P>0.05).Absolute and normalized RTD remained unchanged throughout intervention(P>0.05),but both groups improved impulse(MSP:22.1%±25.7%and TP:12.6%±45.2%,P<0.001).Only MSP responders(n=5)presented significant time effect for absolute RTD(P<0.05)and impulse(P<0.05).Conclusion Although both periodization protocols increased 5-RM:BM and PT,it was not interchangeable through improve-ments in RTD even adopting power training session.Furthermore,these results suggest a great inter-individual variability following different periodization models for aging people.

Effects of Two Isometric Strength Training Methods on Jump and Sprint Performances:A Randomized Controlled Trial

Purpose Isometric strength training (IST) with rapid non-sustained contraction (RIST) is effective in improving the ability to generate force rapidly.However,the neuromuscular adaptation of IST with sustained contraction (SIST) and RIST is not known.Therefore,the aim of the study was to compare the neuromuscular adaptations of RIST with SIST.Methods Thirty-three national floorball players (23.9 ± 3.1 years old;1.69± 0.08 m;64.6± 11.1 kg) were recruited for this study.Pre-and post-test included countermovement jump (CMJ),30-m sprint (TT30),isometric squat at 90° (ISqT90) and 120° (ISqT120) knee angles.They were randomly assigned to either control (Con) (n =9),RIST (n =12) or SIST (n =12)group and performed 12 sessions of intervention training.All groups performed the same sets of exercises,but RIST and SIST had to perform ISqT with and without sustained contraction,respectively.Results Time × group effect for CMJ height (P =0.01,η2p=0.25),peak force (PF) (P =0.03,η2p =0.22) and rate of force development (RFD) (P =0.02,η2p =0.22) obtained from ISqT 120 were noted.A main effect for time was observed in CMJ height,PF obtained from ISqT90 and ISqT120,and RFD obtained from ISqT90 (P < 0.01,0.27 < η2p < 0.57).There was greater improvement in TT30 (P =0.043,d =3.00),ISqT90 PF (P =0.034,d =3.12),ISqT 120 PF (P =0.003,d =4.54) and ISqT120 RFD (P=0.033,d=1.36) in the SIST than the Con group.Conclusion SIST was more effective in improving strength and dynamic performance as compared to RIST,making it a viable training method to enhance dynamic performances.

An examination of acute cross-over effects following unilateral low intensity concentric and eccentric exercise

We compared the effects of low intensity concentric(CON)and eccentric(ECC)exercise on the force and neural responses of the dominant(exercised)elbow flexors(EFs),and studied if these conditions could induce cross-over effects to the contralateral(non-exercised)EFs.Fifteen subjects(8 males)completed all conditions(CON and ECC:6 sets of low intensity exercise to failure;control:rest)in separate visits with a randomized order.Maximal isometric force and electromyography(EMG)of the dominant and contralateral EFs were assessed at pre,immediate-,24-,and 48-h-post.Two-factor(condition and time)linear mixed-model analyses were performed to examine the force and EMG responses.Immediately post CON,contralateral EFs force was significantly(p=0.026)higher(12.41%)than control,but no cross-over effects regarding the neural responses were observed.Immediately post ECC,dominant EFs force was significantly lower in ECC,compared to CON(p=0.003)and control(p<0.001).This force remained depressed at 24-and 48-h post ECC,when compared to CON(p<0.001)and control(p<0.001).Our data suggests that submaximal unilateral exercises are not likely to impair contralateral muscle strength performance.Instead,concentric exercises may acutely improve muscle strength for the contralateral limb.However,this effect is not explained by changes in muscle excitation.