21世纪潜在的绿色能源 --自然冷能

提出了自然冷能概念,说明了自然冷能的普遍性,批明蓄能与高效传热是冷能利用的技术关键,分析了自然冷能应用的广阔领域及发展前景。自然冷能将在２１世纪成为绿色能源中的重要部分。     

世纪之交的地球科学发展展望

本文简介了地球科学在20世纪取得的重大成就,通过对地球科学发展的趋势的思考,提出了21世纪初叶我国地球科学发展的战略重点。     

Normativity,the base-rate fallacy,and some problems for retail realism

Recent literature in the scientific realism debate has been concerned with a particular species of statistical fallacy concerning base-rates, and the worry that no matter how predictively successful our contemporary scientific theories may be, this will tell us absolutely nothing about the likelihood of their truth if our overall sample space contains enough empirically adequate theories that are nevertheless false. In response, both realists and anti-realists have switched their focus from general arguments concerning the reliability and historical track-records of our scientific methodology, to a series of specific arguments and case-studies concerning our reasons to believe individual scientific theories to be true. Such a development however sits in tension with the usual understanding of the scientific realism debate as offering a second-order assessment of our first-order scientific practices, and threatens to undermine the possibility of a distinctive philosophical debate over the approximate truth of our scientific theories. I illustrate this concern with three recent attempts to offer a more localised understanding of the scientific realism debate—due to Stathis Psillos, Juha Saatsi, and Kyle Stanford—and argue that none of these alternatives offer a satisfactory response to the problem.     

Algebraic formulae for the Moon,Saturn and Jupiter in the Pancasiddhantika

Summary The daily motion of the Moon, and the synodic arcs and periods of Saturn and Jupiter are derived from the algebraic formulae given in the Pancasiddhantika.     

Analysis of structural features responsible for the sweetness of the sesquiterpene,hernandulcin

Summary The relationship between sweetness and structure was studied for several analogues of the intensely sweet sesquiterpene, hernandulcin. These derivatives were prepared synthetically, and were subjected to spectroscopic and conformational analysis. With the exception of the parent substance, none of the derivatives tested proved to be sweet. Evidence gathered in this study suggests that hernandulcin binds to its putative receptor through a three-point interaction, involving the C-1 carbonyl and C-1 hydroxyl groups, and the double bond between C-4 and C-5. In the course of a preliminary safety assessment, the 3-desmethyl derivative of hernandulcin was found to be mutagenic towardSalmonella typhimurium strain TM677.Acknowledgments. We thank Drs A. J. Hopfinger and R. Pearlstein for helpful suggestions concerning the use of CHEMLAB software, and Mr E. F. Robbins of the Research Resources Center, University of Illinois at Chicago for helpful assistance with the MS determinations. During the course of this investigation, one of us (C.M.C.) was affiliated with the Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, and the gratefully acknowledges the support and encouragement of the late Professor Martin P. Schulman. J. M. P. is the recipient of a Research Career Development Award from the National Cancer Institute (1984–1989).Paper 14 in the series Potential Sweetening Agents of Plant Origin. For paper 13, see Nanayakkara, N. P. D., Hussain, R. A., Pezzuto, J. M., Soejarto, D. D. and Kinghorn, A. D., J. med. Chem., in press.     

Molecular parasitology: progress towards the development of vaccines for malaria, filariasis, and schistosomiasis

Advances in molecular biology have allowed for the identification of potential vaccine candidates against several parasitic diseases. Antigens from various life stages of Plasmodium and Schistosoma species and filarial worms have been cloned, sequenced and tested as vaccines. Results to date in animal models have been promising. Modest levels of protection against experimental human malaria have been obtained using both sporozoite and blood-stage antigens. However, a greater understanding of the mechanisms which lead to immunity against parasites is required before effective vaccines can be developed.     

Molecular parasitology: Progress towards the development of vaccines for malaria,filariasis, and schistosomiasis

Summary Advances in molecular biology have allowed for the identification of potential vaccine candidates against several parasitic diseases. Antigens from various life stages ofPlasmodium andSchistosoma species and filarial worms have been cloned, sequenced and tested as vaccines. Results to date in animal models have been promising. Modest levels of protection against experimental human malaria have been obtained using both sporozoite and blood-stage antigens. However, a greater understanding of the mechanisms which lead to immunity against parasites is required before effective vaccines can be developed.     

A rapid,sensitive method for the determination of follicle-stimulating activity

Riassunto Gli Autori riportano un nuovo metodo di saggio sul topo di piccole quantità di ormone follicolo stimolante (FSH), basato sulla riduzione intravaginale del cloruro di 2,3,5-trifeniltetrazolio cloruro (TTC). È cosi possibile determinare quantitativamente in sole 30 h dosi di FSH almeno 50 volte inferiori a quelle valutabili con i metodi fino ad oggi proposti.     

Copernicus and Fracastoro: the dedicatory letters to Pope Paul III, the history of astronomy, and the quest for patronage

Copernicus’s De revolutionibus (1543) and Girolamo Fracastoro’s Homocentrica (1538) were both addressed to Pope Paul III (1534-1549). Their dedicatory letters represent a rhetorical exercise in advocating an astronomical reform and an attempt to obtain the papal favour. Following on from studies carried out by Westman (1990) and Barker & Goldstein (2003), this paper deals with cultural, intellectual and scientific motives of both texts, and aims at underlining possible relations between them, such as that Copernicus knew of Fracastoro’s Homocentrica, and that at least part of the rhetorical strategy laid out in De revolutionibus’s dedicatory letter can be read as a sophisticated response to Fracastoro’s arguments.     

Search for the neurodepressing hormone in a stomatopod,Squilla mantis

Summary Crude extracts ofSquilla mantis eyestalks have no neurodepressing activity in theProcambarus bouvieri bioassay. However, partially purified extracts show a very high level of neurodepressing hormone with the same characteristics as the decapod hormone.This investigation was supported by grant No. 192 from the Consejo Nacional de Ciencia y Tecnologia, and by a grant from Fondo de Fomento Educativo. We are very thankful to Dr Victor Anaya for performing the bioassays.