Time series analyses reveal transient relationships between abundance of larval anchovy and environmental variables in the coastal waters southwest of Taiwan

We investigated environmental effects on larval anchovy fluctuations (based on CPUE from 1980 to 2000) in the waters off southwestern Taiwan using advanced time series analyses, including the state-space approach to remove seasonality, wavelet analysis to investigate transient relationships, and stationary bootstrap to test correlation between time series. For large-scale environmental effects, we used the Southern Oscillation Index (SOI) to represent the El Niño Southern Oscillation (ENSO); for local hydrographic conditions, we used sea surface temperature (SST), river runoff, and mixing conditions. Whereas the anchovy catch consisted of a northern species ( Engraulis japonicus ) and two southern species ( Encrasicholina heteroloba and Encrasicholina punctifer ), the magnitude of the anchovy catch appeared to be mainly determined by the strength of Eng. japonicus (Japanese anchovy). The main factor that caused the interannual variation of anchovy CPUE might change through time. The CPUE showed a negative correlation with combination of water temperature and river runoff before 1987 and a positive correlation with river runoff after 1988. Whereas a significant negative correlation between CPUE and ENSOs existed, this correlation was driven completely by the low-frequency ENSO events and explained only 10% of the variance. Several previous studies on this population emphasized that the fluctuations of larval anchovy abundance were determined by local SST. Our analyses indicated that such a correlation was transient and simply reflected ENSO signals. Recent advances in physical oceanography around Taiwan showed that the ENSOs reduced the strength of the Asian monsoon and thus weakened the China Coastal Current toward Taiwan. The decline of larval anchovy during ENSO may be due to reduced China Coastal Current, which is important in facilitating the spawning migration of the Japanese anchovy.     

Cryptosporidium parvum infection and management-based risk factors of dairy calves in Taiwan

Cryptosporidiosis is one of the major causes of diarrhea in calves. Cryptosporidium parvum is considered the most important calf diarrhea pathogen in the Cryptosporidium species. Not only could infected calves spread C. parvum, but infected adult cattle could also shed oocysts. The objectives of this study were (1) to investigate the prevalence of C. parvum in dairy herds in Taiwan, including calves, the dams in delivery enclosure, the floor, and the drinking water; (2) to clarify the relationship of diarrhea, management, and C. parvum infection. Twenty dairy herds in Taiwan were selected by random sampling, including 226 calves and 198 dams, and other environmental samples were collected. A questionnaire was filled out by the farm owners to collect information regarding the management of calves and the delivery enclosure. Hierarchical logistic regression was used to analyze the risk factors for C. parvum infection. The prevalence of C. parvum infection in calves was 26.5% (60/226), while in dams, it was 19.7% (39/198). The C. parvum infection in calves increased with environmental contamination of C. parvum and clinical signs of diarrhea, while it decreased with a yard provided in the delivery enclosure. In conclusion, the management of the delivery enclosure appears to be more important for preventing cryptosporidiosis in calves in Taiwan.     

CHANGES IN ECHOCARDIOGRAPHIC VARIABLES OF LEFT VENTRICULAR SIZE AND FUNCTION IN A MODEL OF CANINE NORMOVOLEMIC ANEMIA

The objective of this study was to document changes in echocardiographic variables of left ventricular size and function noninvasively during acute normovolemic anemia. This model was developed as a pilot study with the purpose of providing baseline information to investigate the pathophysiology, and more specifically the effect on the heart, of canine babesiosis-induced anemia. The study group comprised of 11 mature healthy Beagle dogs that weighed between 9 and 15 kg. Severe normovolemic anemia was induced over a 3-4-day period by serial bleeding while maintaining normovolemia by autotransfusing plasma and infusing crystalloids. The dogs were then allowed to recover. Preanemic (mean Hct 46.7%, standard deviation [SD] 2.4%) echocardiographic variables of left ventricular performance (Fractional shortening, ejection fraction, end-systolic and end-diastolic ventricular volumes, cardiac index, and heart rate) were compared with those in the severely (mean Hct 15.3%, SD 1.1%), moderately (Hct mean 24.7%, SD 1.5%), and mildly (mean Hct 33.5%, SD 2.5%) anemic states, and between the anemic states. With the exception of end diastolic volume, there was a statistically significant (P < 0.05) increase in all variables in the severely anemic state vs. the preanemic and the mild and moderate anemic states. In concordance with previous invasive models, a hyperdynamic state of the left ventricle develops in response to experimentally induced acute canine normovolemic anemia in the conscious dog. Echocardiography has promise as a noninvasive technique of evaluating the cardiac changes in dogs having canine babesiosis.     

Xylazine-induced mydriasis in rats and its antagonism by α-adrenergic blocking agents

Pupillary response to xylazine (10-300 micrograms/kg, i.v.) norepinephrine (1-30 micrograms/kg. i.v.) and atropine (3-100 micrograms/kg, i.v.) were observed in rats anaesthetized with pentobarbital. Xylazine caused a dose-dependent mydriasis which was antagonized by a selective alpha 2-adrenergic blocking agent, yohimbine (2.5 mg/kg, i.v.). was less effective in antagonizing this effect of xylazine. A selective alpha 1-adrenergic blocking agent, prazosin (2.5 mg/kg, i.v.) was ineffective in reducing the xylazine-induced mydriasis. In contrast, both phentolamine and prazosin blocked the pupillary dilation produced by norepinephrine, while yohimbine was much less effective in antagonizing norepinephrine-induced mydriasis. Atropine also induced a dose-dependent mydriasis which was not affected by yohimbine pretreatment. The present study suggests that the mydriatic effect of xylazine in the rat is mediated by an adrenergic mechanism, possibly by stimulating the alpha 2-adrenergic receptors in the iris and CNS.     

大元麦条纹病(Helminthosporium gramineum Rubh.)防治研究的初步报告

 江苏省大元麦种植面积约一千余万亩,尤以南通、扬州、监城、镇江四个专区为多。条纹病历年严重,因此防治条纹病以保证增产,实属刻不容缓。