珠溪河流域土地利用变化对面源磷污染的影响研究

探讨土地利用类型变化对磷、泥沙负荷以及截留能力的影响,为制定珠溪河流域面源磷污染治理措施提供重要支撑,也为鄱阳湖流域磷污染精准防治提供科学依据。基于2010年和2018年土地利用数据,采用SWAT模型对珠溪河流域面源磷负荷、泥沙负荷以及径流进行了模拟研究,并结合水文水质实测数据对模型的模拟结果进行评价。结果表明:相关系数R ²和Nash-Suttclife模型效率系数E _NS均满足SWAT模型在研究区的适用要求;泥沙与总磷的负荷强度与耕地、建设用地的覆盖率呈正相关,与林地、草地的覆盖率呈负相关,且总磷负荷强度与泥沙负荷强度有较高的重合性;2010年、2018年土地利用数据的总磷、泥沙年均入河系数分别为0.535、0.736和0.558、0.752,2个时期的泥沙与总磷入河系数中北部大于南部。控制农业生产和农村生活的污染物排放是减少面源污染的重要措施,进行退耕还林或退耕还草能有效截留污染物质以及起到防沙固土的作用。     

Is there a relationship between clinical presentation,diagnostic and radiographic findings and outcome in horses with osteoarthritis of the small tarsal joints?

Reasons for performing study: Despite the possibility that sound horses may have radiographic signs consistent with osteoarthritis of the small tarsal joints (OA‐STJ), a diagnosis of ‘bone spavin’ as a cause of lameness is often made based only on radiographic examination. Objectives: To determine whether severity of radiographic change and response to treatment are correlated with the duration and degree of lameness and the response to intra‐articular anaesthesia in horses with OA‐STJ. Methods: A retrospective study of all horses that showed a positive response to intra‐articular anaesthesia of the STJ was performed. Details of history, clinical presentation and diagnostic findings were recorded. Radiographs of affected tarsi were evaluated and scored independently by 2 observers. Follow‐up was via a telephone questionnaire with the owner. Statistical analysis was used to assess the association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings. Response to treatment was compared with the findings from the diagnostic work‐up. Results: Ninety‐one horses were included (61 unilateral and 30 bilateral lameness). Fifty‐nine percent of horses had been lame for over 2 months. There was no association between the duration and degree of lameness, or between duration or degree of lameness, intra‐articular anaesthesia and radiographic findings. Response to treatment showed a significant positive association with less severe radiographic changes within the tarsometatarsal (TMT) joint. Follow‐up was available for 48% of cases, with 52% horses returning to the same level of exercise. Conclusions: There is no association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings in horses with OA‐STJ. However, horses that improved following treatment tended to have less marked TMT joint pathology. Potential relevance: Response to intra‐articular anaesthesia should remain the gold standard for diagnosis of OA‐STJ. Predicting which cases are likely to improve following treatment remains difficult.     

Outbreak of Lawsonia intracellularis on a Standardbred breeding farm in North Carolina

Lawsonia intracellularis is a cause of protein‐losing enteropathy in weanling foals commonly causing signs including diarrhoea, oedema and unthrifty appearance. It has previously been reported as sporadic cases throughout the USA, Canada and Europe. Only recently have outbreaks on a single farm location been reported. The cases reported here are an example of multiple foals on a single farm testing serologically positive for L. intracellularis. These foals ranged in severity from asymptomatic to severely hypoproteinaemic and septic; however, none of the foals ever displayed diarrhoea, which is the most common presenting sign of this disease process.     

植物篱模式下小流域退耕还草生态农业可持续发展模式研究

坡耕地是泥沙的主要策源地,虽然25°以上的坡耕地属于国家政策明令退耕区,但由于多数山地农业种植区存在耕地面积不足、农业燃料、饲料紧缺等问题,致使经济发展、农业生产生活与水土保持之间存在资源竞争的矛盾。基于此,提出采用等高固氮植物篱综合技术体系应对这一问题,在此基础上构建了适合小流域在进行25°以上坡耕地退耕还草后生态农业可持续发展的经济模式,并分析了该模式的效益,结果表明,采用植物篱技术进行退耕能够有效地促进山区生态农业的可持续发展。     

近25年青海湖流域土地利用变化及其生态系统稳定性评价——以刚察县为例

青海湖流域位于青藏高原高寒区,是全球生态变化的敏感地区之一。在3S技术的基础上,利用土地利用转移矩阵,土地利用动态度模型全面揭示研究区25年的LUCC时空变化特征,并借鉴已构建的景观弹性度指数分析了研究区的景观生态系统稳定性。结果表明,1977~2000年青海湖流域刚察县土地利用类型已经发生了较大变化：生态用地数量逐渐减少,生产用地、退化土地面积不断增加;县内1987~2000年冰川及永久积雪面积减少速率显著上升达7.7%,而裸岩沙地面积增加速率显著上升达0.41%,其他主要类型土地面积变化速率不断减缓;从1977~2000年,刚察县景观弹性度持续增加,维持景观稳定性的能力相对较高,生态系统健康状态也较高。     

The prevalence and significance of hyperglycemia in hospitalized cats

Objective – To report the prevalence of hyperglycemia in cats admitted to a veterinary hospital and to determine if hyperglycemic cats had increased morbidity and mortality when compared with normoglycemic cats.
Design – Retrospective clinical study.
Setting – Community-based referral hospital.
Animals – Nondiabetic cats admitted to the hospital.
Interventions – None.
Measurements and Main Results – The medical records of nondiabetic cats admitted to the hospital over a 1-year period were reviewed. There were 182 cats that met the criteria for inclusion in the study. Information obtained included signalment, length of hospitalization, initial and highest blood glucose measurement, diagnosis, treatment, and final disposition. Sixty-three percent of cats (116/182) were hyperglycemic at the time of presentation. Total incidence of hyperglycemia at any point during hospitalization was 64% (118/182). No association was found between hyperglycemia either initially or at any point during the hospitalization and mortality. However, a significant association was documented between the presence of hyperglycemia and increased length of hospitalization (LOH) ( P =0.04). The duration of LOH was also significantly associated with the degree of hyperglycemia ( P =0.01). A number of different disease processes were represented in the study population. However, the number of cats in each disease category was small and no association could be found between any of them and blood glucose affecting mortality and morbidity.
Conclusion – The prevalence of hyperglycemia in feline patients admitted to a primary referral hospital was 64%. Cats with hyperglycemia had a longer LOH when compared with normoglycemic cats; however, presence of hyperglycemia did not impact mortality in this population of cats.     

外排泵抑制剂小肽1号对抗菌药抗菌活性的影响

为了观察外排泵抑制剂小肽1号对抗菌药抗菌活性的影响,本试验采用标准微量稀释法,测定了6类8种抗菌药单用和与小肽1号联用对12株临床分离鸡大肠杆菌的MIC值。结果表明,12株鸡大肠杆菌中有9株为产超广谱酶的多重耐药菌株,小肽1号（1∶2）使恩诺沙星等8种药物的抗菌活性多数增强2倍,使氟苯尼考对A8、A15的抗菌活性增强了4倍,小肽1号（1∶2或1∶4）使恩诺沙星、甲替沙星、环丙沙星的抗菌活性增强2倍,使左旋氧氟沙星对A13的抗菌活性增强4倍。以上结果表明,细菌外排泵抑制剂-小肽1号对大多数药物的抗菌活性有一定的增强作用,产酶多重耐药的鸡大肠杆菌至少同时存在产ESBLs、外排泵两种耐药机制。     

小肽对反刍动物乳蛋白合成影响的研究进展

小肽能被乳腺组织有效利用,用于弥补乳蛋白合成过程中游离氨基酸供应的不足,因此有必要研究小肽在反刍动物体内的代谢及其在乳蛋白合成过程中的作用,加深人们对反刍动物利用氨基酸的了解。作者从肽的概念、乳蛋白对小肽的利用、乳腺对小肽的吸收机制、影响乳腺对小肽利用的因素及其研究展望等方面对反刍动物乳腺的小肽代谢进行了综述。     

流域生态需水学科维度方法研究与展望

综合运用专家调查问卷、比较分析和统计学方法,系统研究了流域生态环境需水方法论与维度问题,分析了不同特征的流域如何选取和优化学科方法,从学科维度探讨了方法特征、使用范围、优选和发展趋势。结果表明,流域生态需水方法论可以从方法、学科、空间维度和程序维度4个方面进行研究。根据发展阶段和问题需求,目前学科维度重要性居于首位,重要性顺序为：学科维度（46%）〉方法维度（33%）〉空间维度（12%）〉程序维度（8%）。学科各子维度方法数量依次为：水文学方法（31%）〉生态学方法（28%）〉其他方法（21%）〉水力学方法（12%）〉综合法（8%）。比较不同学科方法计算同流域的生态需水量结果相对标准偏差均大于0.25,差异性较大。流域生态环境需水方法在学科维度层面呈现从单学科分析向多学科综合发展、从局部过程向全流域水文循环过程发展、从传统技术向数字流域技术发展的趋势。建议以流域水环境问题为导向,以流域生态系统管理和系统优化理论为指导,以生态优先和保证基流为基本原则,对于生态参数和科学方法进行科学筛选、整合与优化。     

松花江流域侵蚀产沙演变特征分析

利用松花江流域116个站点的降水资料和14个典型流域水文站的径流泥沙资料,在分析降水、径流和输沙时间变化特征的基础上,研究了该区侵蚀产沙演变特征及其主要影响因素.研究结果表明,1961-1990年松花江流域降水和径流无显著增长趋势,但输沙量增长显著,每10 a平均增长幅度为34.7%,丘陵漫岗区输沙量增长幅度较山区更为显著.流域输沙量自1979年开始显著增加,降水量变化不是输沙量快速增长的主要原因,人类活动导致的下垫面变化可能是输沙量增加的重要原因.