Effect of increasing GnRH and PGF2α dose during Double-Ovsynch on ovulatory response,luteal regression,and fertility of lactating dairy cows

Ovsynch-type synchronization of ovulation protocols have suboptimal synchronization rates due to reduced ovulation to the first GnRH treatment and inadequate luteolysis to the prostaglandin F_2α (PGF_2α) treatment before timed artificial insemination (TAI). Our objective was to determine whether increasing the dose of the first GnRH or the PGF_2α treatment during the Breeding-Ovsynch portion of Double-Ovsynch could improve the rates of ovulation and luteolysis and therefore increase pregnancies per artificial insemination (P/AI). In experiment 1, cows were randomly assigned to a two-by-two factorial design to receive either a low (L) or high (H) doses of GnRH (Gonadorelin; 100 vs. 200 μg) and a PGF_2α analogue (cloprostenol; 500 vs. 750 μg) resulting in the following treatments: LL (n = 263), HL (n = 277), LH (n = 270), and HH (n = 274). Transrectal ultrasonography and serum progesterone (P4) were used to assess ovulation to GnRH1, GnRH2, and luteal regression after PGF_2α during Breeding-Ovsynch in a subgroup of cows (n = 651 at each evaluation). Pregnancy status was assessed 29, 39, and 74 days after TAI. In experiment 2, cows were randomly assigned to LL (n = 220) or HH (n = 226) treatment as described for experiment 1. For experiment 1, ovulation to GnRH1 was greater (P = 0.01) for cows receiving H versus L GnRH (66.6% [217/326] vs. 57.5% [187/325]) treatment, but only for cows with elevated P4 at GnRH1. Cows that ovulated to GnRH1 had increased (P < 0.001) fertility compared with cows that did not ovulate (52.2% vs. 38.5%); however, no effect of higher dose of GnRH on fertility was detected. The greater PGF_2α dose increased luteal regression primarily in multiparous cows (P = 0.03) and tended to increase fertility (P = 0.05) only at the pregnancy diagnosis 39 days after TAI. Overall, P/AI was 47.0% at 29 days and 39.7% at 74 days after TAI; P/AI did not differ (P = 0.10) among treatments at 74 days (LL, 34.6%; HL, 40.8%; LH, 42.2%; HH, 40.9%) and was greater (P < 0.001) for primiparous cows than for multiparous cows (46.1% vs. 33.8%). For experiment 2, P/AI did not differ (P = 0.21) between H versus L treatments (44.2% [100/226] vs. 40.5% [89/220]). Thus, despite an increase in ovulatory response to GnRH1 and luteal regression to PGF_2α, there were only marginal effects of increasing dose of GnRH or PGF_2α on fertility to TAI after Double-Ovsynch.     

EXAMINING THE FULL EFFECTS OF LANDSCAPE HETEROGENEITY ON SPATIAL GENETIC VARIATION: A MULTIPLE MATRIX REGRESSION APPROACH FOR QUANTIFYING GEOGRAPHIC AND ECOLOGICAL ISOLATION

Understanding the effects of landscape heterogeneity on spatial genetic variation is a primary goal of landscape genetics. Ecological and geographic variables can contribute to genetic structure through geographic isolation, in which geographic barriers and distances restrict gene flow, and ecological isolation, in which gene flow among populations inhabiting different environments is limited by selection against dispersers moving between them. Although methods have been developed to study geographic isolation in detail, ecological isolation has received much less attention, partly because disentangling the effects of these mechanisms is inherently difficult. Here, I describe a novel approach for quantifying the effects of geographic and ecological isolation using multiple matrix regression with randomization. I explored the parameter space over which this method is effective using a series of individual‐based simulations and found that it accurately describes the effects of geographic and ecological isolation over a wide range of conditions. I also applied this method to a set of real‐world datasets to show that ecological isolation is an often overlooked but important contributor to patterns of spatial genetic variation and to demonstrate how this analysis can provide new insights into how landscapes contribute to the evolution of genetic variation in nature.     

A plant‐traits approach to assessing the success of alien weed species in irrigated Mediterranean orchards

In addition to their impact on natural habitats, invasive alien plants can have a significant negative effect on agricultural systems and cause economic losses. Flood‐irrigated orchards in the Mediterranean Basin are vulnerable to the invasion of alien weeds, primarily because of the traditional management practices used in the orchards, which are characterized by high soil moisture during the dry summer period, nutrient availability and high levels of disturbance. This study sought to determine whether their biological traits can explain the success of alien weed species. To answer this question, 408 floristic relevés were conducted in 136 flood‐irrigated orchards on the Plains of Lleida (Catalonia, NE of Spain). Richness and cover of native and alien weeds were compared. Furthermore, a set of biological traits were compared between successful and non‐successful weeds for the whole data and separately between native and alien weeds using logistic regression and classification trees. In flood‐irrigated orchards, alien species covered most of their area, even though the richness of alien species was lower than that of the native species. The most important species were C4 species with seeds dispersed by water, and on the other hand, rosulate and caespitose‐reptant hemicryptophytes with long flowering period. Most of these traits fitted with those of the invasive alien weeds, which were mostly C4 species with seeds dispersed by water. Perennial life form characterized successful native weeds. In this study, we discuss how the traditional management of flood irrigation in fruit‐tree orchards favours invasive alien weeds that have specific traits, acting as a reservoir for the spread of alien weeds into other crops and surrounding riparian habitats. We also propose changing management practices in order to avoid the selection of alien weeds and to promote native species.     

Testing for size and allometric differences in fossil hominin body mass estimation

Body size reconstructions of fossil hominins allow us to infer many things about their evolution and lifestyle, including diet, metabolic requirements, locomotion, and brain/body size relationships. The importance of these implications compels anthropologists to attempt body mass estimation from fragmentary fossil hominin specimens. Most calculations require a known “calibration” sample usually composed of modern humans or other extant apes. Caution must be taken in these analyses, as estimates are sensitive to overall size and allometric differences between the fossil hominin and the reference sample. Am J Phys Anthropol 151:215–229, 2013. © 2013 Wiley Periodicals, Inc.     

以小时为步长的大兴安岭兴安落叶松林地表可燃物含水率预测模型

应用时滞平衡含水率法(包括Nelson和Simard两种)及气象要素回归法,以小时为步长对大兴安岭地区阳坡上部落叶松林下地表细小死可燃物进行动态含水率测定,分析了不同郁闭度林分的预测误差.结果表明:以小时为步长的可燃物含水率预测方法适用于大兴安岭地区的典型落叶松林分,Simard法预测平均绝对误差为1.1%,平均相对误差为8.5%,低于Nelson法和传统的气象要素回归法,接近同类研究的误差范围;同一坡度、坡位上,不同郁闭度下的可燃物含水率变化差异较大,使用以小时为步长的可燃物含水率预测方法,应根据不同地区林分和地点选择合适的平衡含水率模型,或建立基于林分的可燃物含水率模型.     

Dynamics of a mechanistically derived stoichiometric producer-grazer model

One of the simplest predator-prey models that tracks the quantity and the quality of prey is the one proposed by [I. Loladze, Y. Kuang, and J.J. Elser, Stoichiometry in producer-grazer systems: Linking energy flow with element cycling, Bull. Math. Biol. 62 (2000) pp. 1137–1162.] (LKE model). In it, the ratio of two essential chemical elements, carbon to phosphorus, C:P, represents prey quality. However, that model does not explicitly track P neither in the prey nor in the media that supports the prey. Here, we extend the LKE model by mechanistically deriving and accounting for P in both the prey and the media. Bifurcation diagrams and simulations show that our model behaves similarly to the LKE model. However, in the intermediate range of the carrying capacity, especially near the homoclinic bifurcation point for the carrying capacity, quantitative behaviour of our model is different. We analyze positive invariant region and stability of boundary steady states. We show that as the uptake rate of P by producer becomes infinite, LKE models become the limiting case of our model. Furthermore, our model can be readily extended to multiple producers and consumers.     

Determination of endogenous faecal phosphorus loss in goats

Four black Liuyang wether goats were fed with corn stover and concentrate formulated to contain four levels of dietary phosphorus (P), including 0.129, 0.140, 0.162 and 0.180% of P. In a 4 × 4 Latin square experiment the endogenous faecal P loss was determined by the regression technique and the substitution method. Treatment effects on faecal and urinary P output, apparent P digestibility and P retention, and saliva P secretion were not significant. A linear relationship was observed between apparent faecal digestible P (Y, g/kg DMI) and P intake (X, g/kg DMI), which was described by the equation: Y = 0.4799X ?0.9209, r² = 0.9869, (p < 0.05). The true P digestibility determined by the regression technique and the substitution method amounted to 48.0 and 48.9%, respectively; the recorded endogenous faecal P losses were 0.92 and 0.93 g/kg DMI, respectively. The study demonstrated the potential of the regression method as well as the substitution method for estimation of true P digestibility and endogenous faecal P losses in goats.     

Validity of ultrasound muscle thickness measurements for predicting leg skeletal muscle mass in healthy Japanese middle-aged and older individuals

Background

The skeletal muscle mass of the lower limb plays a role in its mobility during daily life. From the perspective of physical resources, leg muscle mass dominantly decreases after the end of the fifth decade. Therefore, an accurate estimate of the muscle mass is important for the middle-aged and older population. The present study aimed to clarify the validity of ultrasound muscle thickness (MT) measurements for predicting leg skeletal muscle mass (SM) in the healthy Japanese middle-aged and older population.

Findings

MTs at four sites of the lower limb and the bone-free lean tissue mass (LTM) of the right leg were determined using brightness-mode ultrasonography and dual-energy X-ray absorptiometry (DXA), respectively, in 44 women and 33 men, 52- to 78-years old. LTM was used as a representative variable of leg skeletal muscle mass. In the model-development group (30 women and 22 men), regression analysis produced an equation with R² and standard error of the estimate (SEE) of 0.958 and 0.3 kg, respectively: LTM (kg) = 0.01464 × (MT_SUM×L) (cm²) - 2.767, where MT_SUM is the sum of the product of MTs at four sites, and L is length of segment where MT is determined. The estimated LTM (7.0 ± 1.7 kg) did not significantly differ from the measured LTM (7.0 ± 1.7 kg), without a significant systematic error on a Bland-Altman plot. The application of this equation for the cross-validation group (14 women and 11 men) did not yield a significant difference between the measured (7.2 ± 1.6 kg) or estimated (7.2 ± 1.6 kg) LTM and systematic error.

Conclusion

The developed prediction equation may be useful for estimating the lean tissue mass of the lower extremity for the healthy Japanese middle-aged and older population.     

燕麦种质资源重要农艺性状适应性和稳定性评价

为客观评价燕麦种质资源重要农艺性状的适应性和稳定性,本研究利用加权隶属函数法分析了81份燕麦种质材料在7个试验点的株高等7个重要农艺性状的遗传差异,以加权隶属函数值(D值)构建基因型×环境的GGE双标图,分析裸燕麦、皮燕麦在不同试验点的适应性和稳定性。结果表明:主穗粒重是裸燕麦材料在所有试验点中变异程度最大的性状,有效分蘖数是皮燕麦中变异程度最大的性状,其余5个性状的变异程度与皮裸性几乎无关;加权隶属函数法结合GGE双标图在对燕麦农艺性状进行综合分析时具有很好的应用价值;坝莜三号、73014-336、二莜麦、Bauntebue、坝燕一号等材料可用于实际生产,其中的坝莜三号、坝燕一号已是当下河北等地区的主栽品种;晋8609-1、LY03-02、二秋莜麦、64燕麦、品16、Banner、LY01-12等可作为杂交育种的亲本材料。     

磁共振体素内不相干运动扩散加权成像在肺癌所致肺不张影像诊断中的初步应用

目的:探讨磁共振体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion weighted MR Imaging,IVIM-DWI)在肺癌所致肺不张的影像诊断中的初步应用。方法:选取独立肺段肺不张病变患者43例,其中肺癌致肺不张31例(肺癌组),局部炎症致肺不张12例(炎症组)。所有患者在药物治疗或手术前均行3.0T磁共振IVIM-DWI检查,b值取0、50、100、200、400、600、800、1000 s/mm~2,分别测量灌注分数(perfusion fraction,f)、真实扩散系数(diffusion coefficient,D)以及关注相关扩散系数(diffusion coefficient from the perfused compartment,D*),对上述参数值进行相关统计学分析,并依据受试者工作特征曲线(Receiver Operating Characteristic,ROC)对各参数的评价效能进行分析。结果:肺癌组的D值、D*值以及f值分别为(0.64±0.16)×10~(-3)mm~2/s、(19.77±6.16)×10~(-3)mm~2/s以及(29.62±9.74)%,而炎症组的D值、D*值以及f值分别为(0.67±0.14)×10~(-3) mm~2/s、(21.14±8.32)×10~(-3)mm~2/s以及(47.62±11.46)%;经比较,肺癌组D值、D*值与炎症组无统计学差异(P0.05),而二者f值差异显著,有统计学意义(P0.01)。f值最佳阈值为38.42%,此时曲线下面积(Area Under Curve,AUC)为0.94,诊断肺癌的特异度为0.89,敏感度为0.93,阳性预测值为0.92,阴性预测值为0.89。结论:磁共振IVIM-DWI技术在肺癌所致肺不张的影像诊断中具有一定的应用价值。