灌浆期高温对水稻光合特性、内源激素和稻米品质的影响

以2个籼稻品种:温度钝感型品种K30和温度敏感型品种R21为材料,利用人工气候室控温,在水稻灌浆期设置高温(日均温度34.9℃)和适温(日均温度28.0℃)处理,测定不同灌浆时期(5,10,15,20,25d和30d)光合特性、内源激素含量及稻米品质的变化。结果表明,高温增强了K30的光合能力,K30高温处理净光合速率(Pn)在整个灌浆期都明显高于对照;R21在灌浆前期(5、10d和15d)高温处理与适温处理Pn差异不明显,在灌浆后期(20、25d和30d)高温处理Pn下降。高温增加了K30叶片和籽粒脱落酸(ABA)含量;而R21高温处理和适温处理叶片与籽粒ABA含量的对比不明显。高温处理对两个水稻品种叶片和籽粒赤霉素(GA3)与生长素(IAA)含量也有不同程度影响。高温胁迫降低稻米品质,但K30比R21表现出更强的温度钝感特性。     

粒度变化对城市热岛空间格局分析的影响

尺度是景观格局和生态过程研究中的关键问题。综合目前城市热岛效应研究来看,景观格局指数的引入极大推进了热岛格局的定量研究,然而其尺度效应仍未得到重视。由于热岛空间格局与形成过程的复杂性和人类认识的局限性,对其尺度问题有待深入讨论。基于Landsat TM影像反演地表温度,采用均值-标准差分类方法划分热力等级,对珠三角城市热岛格局特征的粒度效应进行了研究。结果显示:随粒度增加,弱势热力斑块类型下降,向相邻斑块转移;景观指数在类型水平和景观水平均受空间粒度影响明显,"临界粒度"现象明显;总体而言,粒度150 m是城市热岛格局特征的临界粒度,对热岛格局进行景观指数计算的适宜粒度范围为30—150 m;不同景观指数粒度效应曲线有所差异,其中斑块密度和平均分维数在两个水平指数上都有较强的规律性;根据各景观指数变化特征,研究区尺度域主要在(30 m,150 m),表明在该尺度范围内构建的热岛效应预测模型可经简单推绎后使用。分析热岛格局随空间粒度变化特征对了解热岛格局的形成机制及进行尺度推绎具有重要意义。     

Comparing applesnails with oranges: the need to standardize measuring techniques when studying <Emphasis Type="Italic">Pomacea</Emphasis>

Although invaders come in all shapes and sizes, several mollusks have recently achieved notoriety as both economically and ecologically costly invaders. Applesnails of the genus Pomacea get their name from reaching the size of an apple. Native to South America, the species P. insularum has recently established reproducing, and potentially invasive, populations in Texas, Alabama, Georgia, and Florida. In contrast to the widely invasive golden applesnail (P. canaliculata), few studies of the channeled species P. insularum exist. In studying similar invasive applesnail species, scientists use several methods of measurement. We have explored the relationships among shell height, operculum width, and weight among juvenile and adult P. insularum and tested their inter-measurer reliability. We also investigated the use of shell height, shell length, and operculum width measurements in P. canaliculata studies and observed whether or not those studies defined their measurements. We found that operculum width served as a significantly more reliable measure among researchers. Furthermore, operculum width better predicted weight than shell height. The majority of articles that measured P. canaliculata did not define their measurements, which may cause problems when comparing studies between native and exotic populations or when comparing the two species. We recommend that future studies of P. insularum use operculum width to measure snails and explore a possible sex dimorphism in the operculum width of adult P. insularum.     

Fractions of barley spent grain as media for growth of probiotic bacteria

The application of the protein and polysaccharide fractions of barley spent grain as a basis of growth media for probiotic bacteria was studied. High values of biomass yield, cell viability, and organic acid production were observed in the variants of media containing the barley spent grain supplemented with lactose, ascorbic acid, yeast extract, and mineral salts. Cells of lactic acid bacteria and bifidobacteria had the typical rod-shaped morphology.     

血清白蛋白、降钙素原联合红细胞分布宽度对重型颅脑损伤患者住院期间死亡风险的预测价值研究

摘要 目的：探讨血清白蛋白（Alb）、降钙素原（PCT）联合红细胞分布宽度（RDW）对重型颅脑损伤（sTBI）患者住院期间死亡风险的预测价值。方法：选取2019年1月～2022年2月长沙市第一医院收治的120例sTBI患者,根据住院期间预后情况分为死亡组和存活组。收集sTBI患者临床资料并检测其血清Alb、PCT、RDW水平。采用多因素Logistic回归分析sTBI患者住院期间预后的影响因素,受试者工作特征（ROC）曲线分析血清Alb、PCT、RDW对sTBI患者住院期间死亡风险的预测价值。结果：120例sTBI患者住院期间死亡率为45.83％（55/120）。体温升高、糖尿病、瞳孔散大、基底池异常、中线移位≥5 mm、蛛网膜下腔出血和PCT、RDW升高为sTBI患者住院期间死亡的独立危险因素,Alb升高、格拉斯哥昏迷量表（GCS）评分增加为独立保护因素（P＜0.05）。血清Alb、PCT、RDW联合预测sTBI患者住院期间死亡风险的曲线下面积大于Alb、PCT、RDW单独预测。结论：临床应重视sTBI患者住院期间预后的影响因素,并采取对应措施进行干预。血清Alb、PCT、RDW联合预测sTBI患者住院期间死亡风险的价值较高,可作为sTBI患者住院期间死亡风险的预警指标。