Effect of 12-hour road transportation on physiological, immunological and haematological parameters in bulls housed at different space allowances

The effects of transporting Holstein Friesian bulls (n=72; bodyweight 403+/-3.5 kg) for 12h by road were examined. Adrenal, haematological and immune responses, body temperature and performance were recorded. The animals had been previously housed for 96 days at three space allowances (1.2, 2.7 or 4.2m(2) per bull). The bulls were allocated to one of two treatments: T (transport for 12h; n=16 per space allowance) and C (control; n=8 per space allowance). Basal cortisol plasma concentrations and interferon (IFN)-gamma production from cultured lymphocytes did not show any statistically significant difference (P>0.05) following the housing period. Removing bulls from their home pens and walking them to the pre-loading crush facility, loading onto the transporter, and unloading following the 12h road journey, significantly (P<0.001) increased plasma cortisol concentration. The bulls housed at 4.2m(2) had greater (P<0.05) plasma cortisol concentrations than bulls housed at 1.2m(2) at loading, unloading, or on return to the crush holding facility; those housed at 1.2m(2) had greater (P<0.05) plasma cortisol concentrations than bulls housed at 2.7 and 4.2m(2) in their home pens after transport. There was an increased (P<0.05) plasma cortisol response in the T than in the C bulls following adrenocorticotrophic hormone administration. Transport significantly reduced (P<0.05) IFN-gamma production, lymphocyte % and body weight and significantly increased (P<0.05) neutrophils, eosinophils, packed cell volume, red blood cell numbers and haemoglobin. In conclusion, housing bulls for 96 days in a range of space allowances did not affect basal cortisol response or immune function parameters. Whereas transport increased plasma cortisol and reduced the immune response in the short-term, the changes were transient and within normal physiological ranges, suggesting that 12h road transport had no adverse effect on welfare status over the longer term. Furthermore, transport of bulls housed at increased space allowance (4.2m(2)/bull) resulted in a greater plasma cortisol response, albeit still within normal physiological range.     

Using fish models to investigate the links between microbiome and social behaviour: The next step for translational microbiome research?

Recent research has revealed surprisingly important connections between animals’ microbiome and social behaviour. Social interactions can affect the composition and function of the microbiome; conversely, the microbiome affects social communication by influencing the hosts’ central nervous system and peripheral chemical communication. These discoveries set the stage for novel research focusing on the evolution and physiology of animal social behaviour in relation to microbial transmission strategies. Here, we discuss the emerging roles of teleost fish models and their potential for advancing research fields, linked to sociality and microbial regulation. We argue that fish models, such as the zebrafish (Danio rerio, Cyprinidae), sticklebacks (?Gasterosteidae), guppies (Poeciliidae) and cleaner–client dyads (e.g., obligate cleaner fish from the Labridae and Gobiidae families and their visiting clientele), will provide valuable insights into the roles of microbiome in shaping social behaviour and vice versa, while also being of direct relevance to the food and ornamental fish trades. The diversity of fish behaviour warrants more interdisciplinary research, including microbiome studies, which should have a strong ecological (field‐derived) approach, together with laboratory‐based cognitive and neurobiological experimentation. The implications of such integrated approaches may be of translational relevance, opening new avenues for future investigation using fish models.     

精密镗床旋转轴几何误差完备性测量与辨识

针对四轴卧式镗床旋转轴需测几何误差的数目不统一与完备性缺失的问题,提出了基于形状创成函数的四轴卧式镗床旋转轴PIGEs形成机理分析方法与旋转轴完备几何误差测量辨识方法。基于形状创成机理构建了卧式镗床几何误差创成函数,确定了旋转轴可通过误差补偿进行调整的最少与位置无关的几何误差(Position-independent geometric error, PIGEs)数目。建立了卧式镗床旋转轴4项PIGEs、6项与位置有关的几何误差(Position-dependent geometric error, PDGEs)、6项安装误差(Setup error, SEs)与球杆仪(Double ball bar, DBB)测量轨迹半径之间的完备性函数模型,设计了基于DBB的四轴联动Viviani曲线测量轨迹,构建了旋转轴6项PDGEs的NURBS表征与PIGEs、SEs辨识方法。开展了误差补偿对比实验验证,结果表明,利用几何误差完备性测量与辨识结果进行误差补偿,较仅单一补偿6项PDGEs可提升圆轨迹测量精度40.69%。     

垂直轴风力机叶片动态失速数值模拟

利用数值计算方法研究了一种典型的大高径比垂直轴风力机叶片动态失速现象。在验证数值计算方法可靠的基础上,结合速度矢量图和涡量图,研究了8 m/s风速时风力机在不同尖速比下叶片动态失速现象以及风轮尺寸改变时风轮动态失速流场及其对风力机功率系数的影响规律。研究表明,尖速比过低,增大弦径比和叶片数均导致叶片动态失速和气流分离呈现加剧趋势,削弱风力机的气动性能。对用于城市风力发电的大高径比垂直轴风力机,应使其在最佳尖速比下运行,同时控制弦径比在0.2~0.4之间,叶片数为3或4,以获得较好的气动性能。     

非对称翼型反装对H型垂直轴风力机流场分布的影响

H型垂直轴风力机(H-VAWT)是典型的升力型垂直轴风力机,且有集群式发展的潜力和优势.文中采用数值模拟的研究方法,建立二维模型,对比分析了使用非对称翼型的H-VAWT叶片反装时的流场结构,以及反装时叶片数对H-VAWT流场分布的影响.结果表明:对于非对称翼型的H-VAWT,叶片反装所产生的尾流湍流强度较叶片正装时大,且尾流的恢复能力差,进而影响到H-VAWT在风场中的布局,但是叶片的正装和反装对H-VAWT附近外流场中Y方向上流场分布的影响基本一致;随着叶片数的增加,反装叶片的H-VAWT本身产生尾流的湍流强度增加,这增强了下风轮区域叶片和上风轮区域叶片所产生湍流的相互作用,但是叶片数为3时,叶片的正装和反装所产生的湍流差别不大.     

叶片数对尾缘加弯板垂直轴风力机功率影响数值模拟

为了探究叶片数量对叶片尾缘加装弯板直线翼垂直轴风力机气动特性的影响,通过不同叶片数量下直线翼叶片尾缘加弯板对垂直轴风力机叶片周围流场改善情况的对比,分析其气动特性变化.选取NACA0018直线翼型作为研究对象,利用数值模拟计算7种弯板长度下,2,3,4这3种叶片数量下的直线翼垂直轴风力机动态输出特性和静态起动特性.研究结果显示:该类升力型垂直轴风力机的气动特性受到叶片数量和弯板长度的综合影响,弯弦比的增加能够提升风力机的阻力性能,但会弱化因叶片数量增加导致风力机产生的功率系数的差别;在不同叶片数量下,适当弯板长度对风力机静态起动性能具有优化作用,但其起到优化作用的方位角不同,且2叶片时优化效果最佳,平均转矩系数提升40%.该研究为垂直轴风力机叶片尾缘的设计与优化提供依据.     

Effects of Estradiol and Testosterone on the Expression of Growth‐related Genes in Female and Male Nile Tilapia,Oreochromis niloticus

Nile tilapia exhibits strong sexual growth dimorphism. The potential role of sex steroid hormones in sexual growth dimorphism is not fully understood. We investigated the effects of estradiol (E₂) and testosterone (T) on growth rate, plasma sex hormones, and expression of growth hormone (GH)‐insulin‐like growth factor (IGF) axis genes and muscle regulatory factor (MRF) genes in female and male Nile tilapia. The results revealed that serum concentrations of E₂ and T were significantly higher after correlative injection (P < 0.05). Compared to male fish, female fish had lower growth rates. E₂ increased growth performance in females with no significant effects on males, whereas T significantly increased growth performance in males, with no significant effects on females. In females, E₂ significantly increased expression of ghr1, ghr2, igf1, and igf2, while T decreased igf2 and increased ghr1 and ghr2 expression. In males, T increased expression of igf1, igf2, ghr1, and ghr2, and E₂ decreased expression of igf1, ghr1, and ghr2. Additionally, E₂ and T enhanced the expression of MRF genes (myod1, myod2, myog, and myf5) in female and male fish, respectively. The results suggest that sex steroid hormones play a role in sexual growth dimorphism by regulating the expression of GH‐IGF axis and MRF genes.     

低风速下H型垂直轴风力机气动性能

为了准确地研究低风速下H型垂直轴风力机的特性,以自主研发的H型垂直轴风力机为研究对象,采用数值模拟方法,分析了低风速下H型垂直轴风力机的气动性能和三维效应特征.分析结果表明:低风速区域,保持叶尖速比不变,改变风轮转速或来流风速,对H型垂直轴风力机的功率系数影响较大,且风速对叶尖速比的影响比转速的影响更敏感;在低风速区域,即使转速较大,风力机实际仍工作在低叶尖速比区域;在数值模拟中,设定合理的风速和转速的匹配有利于提高模拟结果的可靠性;在不考虑风剪切的情况下,三维效应受叶尖涡影响,且叶尖涡在0°方位角的位置时影响较大,同时还受风轮内流场的作用,且这种作用随着转速的增加而增强.计算结果为进一步研究H型垂直轴风力机提供了参考.     

Hypothalamic-Pituitary-Adrenal Axis Assessment in Healthy Term Neonatal Foals Utilizing a Paired Low Dose/High Dose ACTH Stimulation Test

Background: Hypothalamic-pituitary-adrenal (HPA) axis function is dynamic in the neonatal foal. The paired low dose/high dose cosyntropin (ACTH) stimulation test allows comprehensive HPA axis assessment, but has not been evaluated in neonatal foals.
Hypothesis: Foal age will significantly affect cortisol responses to a paired 10 and 100 μg dose cosyntropin stimulation test in healthy neonatal foals.
Animals: Twenty healthy neonatal foals.
Methods: HPA axis function was assessed in 12 foals at birth and at 12–24, 36–48 hours, and 5–7 days of age. At each age, basal cortisol and ACTH concentrations were measured and cortisol responses to 10 and 100 μg cosyntropin were assessed with a paired ACTH stimulation test protocol. Eight additional 36–48-hour-old foals received saline instead of 10 μg cosyntropin in the same-paired ACTH stimulation test design.
Results: At birth, foals had significantly higher basal cortisol and ACTH concentrations and higher basal ACTH : cortisol ratios compared with foals in all other age groups. A significant cortisol response to both the 10 and 100 μg doses of cosyntropin was observed in all foals. The magnitude of the cortisol response to both doses of cosyntropin was significantly different across age groups, with the most marked responses in younger foals. There was no effect of the paired ACTH stimulation test design itself on cortisol responses.
Conclusions and Clinical Importance: A paired 10 and 100 μg cosyntropin stimulation test can be used to evaluate HPA axis function in neonatal foals. Consideration of foal age is important in interpretation of HPA axis assessment.     

GnRH在青年摩杂一代水牛下丘脑-垂体-卵巢轴的免疫组化定位

[目的]研究促性腺激素释放激素（GnRH）在青年摩杂一代水牛下丘脑-垂体-卵巢轴的免疫组化定位。[方法]采用免疫组织化学SuperPicTure^TM二步法检测5头青年摩杂一代水牛下丘脑、垂体和卵巢中GnRH的分布情况,研究GnRH在下丘脑、垂体及卵巢的分布上的联系,进而了解GnRH在下丘脑、垂体及卵巢三者之间分泌释放的途径。[结果]GnRH存在于青年摩杂一代水牛下丘脑-垂体-卵巢轴的各个环节。青年摩杂一代水牛下丘脑中各主要核团都有GnRH免疫阳性神经元的分布,尤其以视上核、视前核、室旁核分布较多。对于垂体,GnRH免疫阳性产物只存在于青年摩杂一代水牛的腺垂体中。青年摩杂一代水牛卵巢中生殖上皮细胞、颗粒细胞和黄体细胞发现有GnRH免疫阳性产物。[结论]为进一步研究GnRH在生殖中的生理和作用机制提供形态学依据,并对青年摩杂一代水牛的繁殖育种起到参考指导作用。