Oscillation Heuristics for the Two-group Classification Problem

We propose a new nonparametric family of oscillation heuristics for improving linear classifiers in the two-group discriminant problem. The heuristics are motivated by the intuition that the classification accuracy of a separating hyperplane can be improved through small perturbations to its slope and position, accomplished by substituting training observations near the hyperplane for those used to generate it. In an extensive simulation study, using data generated from multivariate normal distributions under a variety of conditions, the oscillation heuristics consistently improve upon the classical linear and logistic discriminant functions, as well as two published linear programming-based heuristics and a linear Support Vector Machine. Added to any of the methods above, they approach, and frequently attain, the best possible accuracy on the training samples, as determined by a mixed-integer programming (MIP) model, at a much smaller computational cost. They also improve expected accuracy on the overall populations when the populations overlap significantly and the heuristics are trained with large samples, at least in situations where the data conditions do not explicitly favor a particular classifier.     

Mast cell lines produce lymphokines in response to cross-linkage of Fc epsilon RI or to calcium ionophores

The cross-linkage of high affinity Fc epsilon receptors (Fc epsilon RI) on mast cells and basophils is central to the induction of allergic inflammatory responses. As a result of such cross-linkage, mast cells secrete a variety of preformed biologically active substances, such as histamine, and newly synthesized arachidonic acid metabolites. Here we show that cross-linkage of Fc epsilon RI on a series of nontransformed murine mast cell lines, or treatment of these cells with calcium ionophores, stimulates increased messenger RNA levels and secretion of a group of lymphokines classically produced by a subset of murine T cell lines (TH2 cells). These factors include interleukin-3 (a mast cell growth factor)s interleukin-4 (an IgE 'switch factor'), interleukin-5 (an eosinophil differentiation factor) and interleukin-6 (a factor controlling immunoglobulin secretion). The production of these polypeptide factors by mast cells may have great importance in the induction of allergic and anti-parasite inflammatory responses.     

微甘菊生活史及其对除莠剂的反应研究

微甘菊种子细小．千粒重０．０８９２ｇ，在自然条件下６～８天内完全萌发，萌发率９５．３％。种子萌发最适温度２５～３０℃，４０℃可使种子完全丧失萌发能力，５℃则明显抑制种子萌发。无性繁殖的营养生长比实生苗生长更快，光照对种子萌发和营养生长都有明显的促进作用。有性繁殖期是在９月至翌年２月，这时花的生物量占植株地上部分总生物量的３８．７％～４２．８％。小花从现蕾、盛开到受精形成成熟种子仅１５～１７天，但每天需光照１２ｈ左右才能正常结实。除莠剂“兰达”（Ｒｏｕｎｄｕｐ）、“草坝王”（Ｂｅｎｔａｚｏｎ）、“毒莠定”（ＴＯＲＤＯＮ）和“恶草灵”（ＲＯＮＳＴＡＲ）都对微甘菊种子和幼苗有杀灭作用，其中以浓度为０．４％的“草坝王”和０．２％的“毒莠定”效果较佳。     

Potential toxins of acute liver failure and their effects on blood-brain barrier permeability

The effects of potentials toxins of hepatic coma on the blood-brain barrier (BBB) permeability of the rat have been examined using the Oldendorf technique. Classical toxins of hepatic failure such as ammonia, methyl octanoate, mercaptans, and phenol caused significant increases in BBB permeability. A slight increase in permeability occurred following infusion of peroxidized linoleic acid and unconjugated bilirubin but no increase after infusion of bile acids. E. coli endotoxin infused into rats following partial hepatectomy also increased the BBB permeability.