The effect of age and teat order on alpha1-acid glycoprotein, neutrophil-to-lymphocyte ratio, cortisol, and average daily gain in commercial growing pigs

The objectives of the study were to evaluate age and teat order on a performance trait, average daily gain, and on physiological stress indicators, alpha1-acid glycoprotein (AGP), neutrophil-to-lymphocyte ratio (N:L), and cortisol in commercial growing pigs from weaning to market age. Pigs (n = 129) from five commercial California farms were weighed and blood-sampled at 28-d intervals from 28 to 168 d of age. Laboratory assays were performed from blood samples to quantify cortisol, AGP, and N:L. Age and facility effects (P<.001), but not teat order effects (P>.05), were found for all three physiological traits and ADG. Pigs that routinely suckled from teats 1, 4, or 6 (numbered from anterior to posterior on the upper teat bank) had similar (P>.05) ADG and BW throughout the production cycle. No correlation (P> .05) was found between cortisol, AGP, and N:L. The use of these physiological and production traits as stress and health indices of growing pigs in commercial facilities has limitations in comparing data between facilities or different ages of pigs.     

Abortifacient effects of a unique class of vasoactive lipids from Pinus ponderosa needles.

Pinus ponderosa needle (PN) ingestion by late pregnant cows results in decreased uterine blood flow, premature parturition, and retained placentae. Further, plasma from PN-fed cows increases caruncular arterial tone (i.e., induces prolonged contraction) in an isolated perfused bovine placentome. A novel class of vasoactive lipids was isolated and identified using a bovine placentome assay-guided fractionation of CH2Cl2 extracts of PN. Placentome perfusion tests indicated that 1-12-dodecanedioyl-dimyristate (14-12-14) was the most potent of the PN lipids for increasing caruncular arterial tone. Late pregnant guinea pigs (GP) were used to evaluate the abortifacient activity of these vasoactive lipids. In Study 1, on d 50 of gestation, part of the control diet was replaced with chopped PN (Diet A) or chopped PN subjected to sequential extraction with diethyl ether (Et2O; Diet B); Et2O and CH2Cl2 (Diet C); and Et2O, CH2Cl2, and methanol (Diet D). The GP on Diets A and B exhibited shorter (P<.01) gestation lengths and reduced (P<.01) pig birth weights than GP on the control diet or Diets C and D. Further, only GP on Diets A and B exhibited retained placentae. In Study 2, on d 50 of gestation, part of the control diet was replaced with chopped PN that had been subjected to exhaustive CH2Cl2 extraction and then infiltrated with either CH2Cl2 alone (Diet E), CH2Cl2 containing 14-12-14 (Diet F), or CH2Cl2 containing isocupressic acid (Diet G); then solvents were evaporated. The GP consuming Diet F had shorter (P<.05) gestation lengths and reduced (P<.05) pig birth weights than did GP consuming Diets E or G. The GP consuming Diet F also exhibited a high incidence of retained placentae. These data provide evidence that a unique class of vasoactive lipids in PN exhibit abortifacient activity in guinea pigs.     

Photonic band gap guidance in optical fibers

A fundamentally different type of optical waveguide structure is demonstrated, in which light is confined to the vicinity of a low-index region by a two-dimensional photonic band gap crystal. The waveguide consists of an extra air hole in an otherwise regular honeycomb pattern of holes running down the length of a fine silica glass fiber. Optical fibers based on this waveguide mechanism support guided modes with extraordinary properties.     

不同时期滴灌氮量对冀西北坝上地区洋葱产量和品质的影响

以洋葱品种"红贝特"为试材,设4个施氮水平处理N0、N1、N_2、N3,以CK为对照,测定了膜下滴灌洋葱的植株性状、鳞茎性状、品质和产量等指标,以探讨冀西北坝上地区地膜覆盖洋葱适宜的滴灌氮量,给当地洋葱施肥提供合理施肥依据。结果表明:处理N1的植株性状、鳞茎性状均显著高于CK,产量较CK提高12.26%;处理N1可溶性蛋白质、可溶性固形物、可溶性糖和维生素C含量较CK分别增加27.13%、8.16%、19.15%和60.71%,而硝酸盐含量CK较N1提高85.67%;在该试验条件下,洋葱获得最佳效益时的氮肥施用量和时期分别为苗期追N 31.5kg·hm~(-2),茎叶生长期追N 47.25kg·hm~(-2),鳞茎膨大初期追N 47.25kg·hm~(-2),鳞茎膨大中期追N 31.5kg·hm~(-2),并在整个生长时期配施P_2O_575kg·hm~(-2),配施K_2O 255kg·hm~(-2)。     

基于层次分析法的天然甜型葡萄酒原料种植区划评价

运用层次分析法和模糊数学综合评判方法,对新疆天然甜型葡萄酒原料种植区域进行了研究,并建立了数学模型.结果表明,吐鲁番的评价最高,其次为和田,昌吉为不适宜种植区.     

蝗虫微孢子虫病在优势蝗虫种类中的持续传播

对施用蝗虫微孢子虫后1-10年的草场中5种主要蝗虫种群中微孢子虫病的流行状况进行了研究,结果表明,蝗虫微孢子虫病能在蝗群中长期传播,蝗虫种群的感病率和感染指数呈波动趋势,随着施用后年限的增加,波幅变动范围趋于稳定。感染率波幅范围为20％-80％,感染指数为10％-41％;鼓翅皱膝蝗、白边痂蝗和毛足棒角蝗种群对微孢子虫病的感染指数,不同年份波动较大,短期内难以形成一个稳定的流行群体;而在小车蝗和宽须蚁蝗种群中引入微孢子虫4年后,感染指数下降,但能够形成比较稳定的感染群体。     

多壁碳纳米管做吸附剂富集水中有机磷农药残留

目的 研究多壁碳纳米管(MWCNTs)做固相萃取吸附剂对水中的16种有机磷农药残留的吸附富集效果.方法 MWCNTs SPE柱采用水相净化体系,有机磷农药采用双柱双检测器GC/FPD法测定.结果 优化的净化条件为:水样采用HAc-NaAc缓冲溶液调节pH=5.0,MWCNTs SPE柱用5 mL甲醇和5 mL HAc-...     

几种甘蓝型油菜幼苗抗旱性特征的比较研究

以EV1、EV2、EV3、EV4、EV5、EV66个抗旱性不同的油菜品种为试验材料,通过不同浓度PEG-6000渗透溶液模拟干旱胁迫处理,研究油菜幼苗的抗旱指数、根长、苗高和根冠比等性状变化,探索在大田环境条件下的苗期生长特征。结果表明,水分胁迫下EV2的抗旱指数最大,EV6的抗旱指数最小;不同浓度PEG胁迫下,各品种差异显著,EV1、EV2、和EV3的根长、苗高和根冠比较大,而EV5和EV6的表现较差。在大田油菜五叶期时,EV2的冠层覆盖面积最大,与其它品种之间存在极显著性差异;总生物量以EV2、EV3和EV1较大,根系干重以EV2较大,而且三者之间存在显著相关性;与抗旱指数进行通径分析,冠层覆盖面积对抗旱性的直接通径系数最大,达到0．5975。冠层覆盖面积的大小反映了早期活力的强弱,早期活力强,相应的品种抗旱指数高,抗旱性强。