n维空间中质点之间距离分布及其特征

提出了随机分配的质点之间距离分布的概念,给出了最近距离分布公式,得到了最近距离和k次距离分布的众数,矩及质点空间密度D的充分统计量和极大似然估计.     

Nitric oxide regulates the heart by spatial confinement of nitric oxide synthase isoforms

Subcellular localization of nitric oxide (NO) synthases with effector molecules is an important regulatory mechanism for NO signalling. In the heart, NO inhibits L-type Ca2+ channels but stimulates sarcoplasmic reticulum (SR) Ca2+ release, leading to variable effects on myocardial contractility. Here we show that spatial confinement of specific NO synthase isoforms regulates this process. Endothelial NO synthase (NOS3) localizes to caveolae, where compartmentalization with beta-adrenergic receptors and L-type Ca2+ channels allows NO to inhibit beta-adrenergic-induced inotropy. Neuronal NO synthase (NOS1), however, is targeted to cardiac SR. NO stimulation of SR Ca2+ release via the ryanodine receptor (RyR) in vitro, suggests that NOS1 has an opposite, facilitative effect on contractility. We demonstrate that NOS1-deficient mice have suppressed inotropic response, whereas NOS3-deficient mice have enhanced contractility, owing to corresponding changes in SR Ca2+ release. Both NOS1-/- and NOS3-/- mice develop age-related hypertrophy, although only NOS3-/- mice are hypertensive. NOS1/3-/- double knockout mice have suppressed beta-adrenergic responses and an additive phenotype of marked ventricular remodelling. Thus, NOS1 and NOS3 mediate independent, and in some cases opposite, effects on cardiac structure and function.     

Forecasting future canadian residential heating demand: An illustration of forecasting with aggregated and disaggregated data

This paper examines the sensitivity of forecasts to the level of aggregation of the data. A relative shares regression model and a multinominal logit model are tested with both aggregate and disaggregate survey data from 2109 respondents. The results indicate the appropriate model to use depends on whether the data are disaggregate or aggregate in form. Forecasts of solar heating of dwelling unit demand and market shares are also reported for Canada in terms of the solar price relative to the natural gas price and solar reliability relative to natural gas reliability.     

Correlation between the anaesthetic effect of halothane and saturable binding in brain

Two theories of the molecular mechanism of volatile anaesthetic action suggest either that anaesthetics cause a generalized perturbation of neuronal membrane structure, probably through a nonspecific interaction with membrane lipids, or that anaesthetics bind to sets of sites of appropriate molecular dimension on membrane proteins. Based on the recent finding that fluorinated anaesthetics can be observed in animal tissue by 19F nuclear magnetic resonance (19F-NMR) spectroscopy, we have used 19F-NMR to quantify the interaction between the volatile anaesthetic halothane and rat brain tissue. Steady-state brain halothane concentration was found to be a non-linear function of inspired concentration, with apparent saturation of brain occurring at inspired halothane concentrations above 2.5% by volume. Using a spin-echo pulse sequence it was found that halothane exists in two distinct chemical environments in brain, characterized by different spin-spin relaxation times (T2), chemical shifts and kinetics of occupancy. Halothane concentration in one of these environments (T2 = 3.6 ms) was saturated at approximately 2.5% inspired halothane; occupancy of this environment was found to correlate with the anaesthetic effect of the drug. In the other environment (T2 = 43 ms), brain halothane concentration was a linear function of inspired concentration. These data suggest the existence of a saturable anaesthetic site for halothane in brain and do not support the concept that anaesthetics act by nonspecific membrane perturbation.     

CaMnO_3和LaMnO_3的电子结构研究

密度泛函理论(DFT)方法通常难以处理强关联体系,而DFT+U方法的计算结果强烈地依赖于U的取值.利用一种混合了部分DFT交换关联势和非局域Hartree-Fock精确交换势的杂化泛函HSE方法,研究了钙钛矿锰氧化物的两个典型反铁磁绝缘体CaMnO3和LaMnO3的电子结构,分析了二者的能隙特征与Mn离子价态和磁有序态的关联.根据ZSA方案CaMnO3可划分为电荷转移型绝缘体.LaMnO3的能隙表现出各向异性特征,其中沿c轴方向及ab面内的自旋多数通道中能隙的Mott-Hubbard特征更为显著,而自旋少数通道显示出完全的电荷转移型特征.     

Influence of the pineal gland on the reproductive system of the male house mouse

Summary Procedures designed to express pineal-mediated antigonadotropic activity were performed upon male house mice. Neither blinding nor blinding plus olfactory bulbectomy of house mice resulted in testicular involution within 12 weeks. The pineal gland appears to be of little significance to reproduction in the house mouse.Supported by NICHHD grant No. HDO 7119-092.Supported by NICHHD grant No. 5P5 OHDO 8338.Supported by NSF grant No. SPI 7922 372.     

Preparation and biological properties of (-)- and (+)-6-hydroxydopa

Zusammenfassung Die optischen Isomeren von 6-Hydroxydopa wurden synthetisiert und ihr Effekt auf den Katecholaminspiegel verschiedener Organe in der Ratte bestimmt. Dem (–)-Isomeren gegenüber waren Herz und Nebennieren äusserst empfindlich und im Gehirn wurde der Norepinephrinspiegel erniedrigt.

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B.A.B. is the recipient of a Roche Institute of Molecular Biology postdoctoral fellowship.     

和谐就是力量--兼评培根的"知识就是力量"

和谐--无论是结构状态的分布有序还是功能状态的进化有道,都蕴涵着无与伦比的力量与神奇.自我和谐是个人身心微观和谐发展的调适力,人我和谐是社会中观和谐发展的协和力,物我和谐是人与自然宏观和谐发展的自然力,以至在某种意义上我们不得不说,和谐是发展之源,和谐就是力量;反之,自我失衡是身心微观灾变之端,人我失衡是社会中观模糊或畸形运作之始,物我失衡是一场没有胜利的逆变,以至在某种意义上我们不得不说,失衡是畸变之兆,失衡就是耗散."知识就是力量"是一个工具理性张扬的命题,而"和谐就是力量"则是"知识就是力量"的合理升华,是东方智慧的集大成.通过物理学与伦理学的二维证明我们发现,"和谐就是力量"不仅是一个长期被忽视的物理学定律,而且是一个重要的和谐伦理命题.