Solar energy utilization by physical methods     

Wolf M 《Science (New York, N.Y.)》1974,184(4134):382-386

On the basis of the estimated contributions of these differing methods of the utilization of solar energy, their total energy delivery impact on the projected U.S. energy economy (9) can be evaluated (Fig. 5). Despite this late energy impact, the actual sales of solar energy utilization equipment will be significant at an early date. Potential sales in photovoltaic arrays alone could exceed $400 million by 1980, in order to meet the projected capacity buildup (10). Ultimately, the total energy utilization equipment industry should attain an annual sales volume of several tens of billion dollars in the United States, comparable to that of several other energy related industries. Varying amounts of technology development are required to assure the technical and economic feasibility of the different solar energy utilization methods. Several of these developments are far enough along that the paths can be analyzed from the present time to the time of demonstration of technical and economic feasibility, and from there to production and marketing readiness. After that point, a period of market introduction will follow, which will differ in duration according to the type of market addressed. It may be noted that the present rush to find relief from the current energy problem, or to be an early leader in entering a new market, can entail shortcuts in sound engineering practice, particularly in the areas of design for durability and easy maintenance, or of proper application engineering. The result can be loss of customer acceptance, as has been experienced in the past with various products, including solar water heaters. Since this could cause considerable delay in achieving the expected total energy impact, it will be important to spend adequate time at this stage for thorough development. Two other aspects are worth mentioning. The first is concerned with the economic impacts. Upon reflection on this point, one will observe that largescale solar energy utilization will not cause a greater impact than other new energy sources, based on the reasoning that a self-consistent set of conditions will have to be fulfilled in order to achieve such large-scale use. Without cost competitiveness, other energy resources would fill the requirements, or, if their resource and cost structure also would create severe problems, the economic forecasts simply cannot be fulfilled. We also should not think of a "solar-only" energy future. First, there is still enough coal to last for several hundred years. Second, there should be enough fissionable fuel available to operate breeder reactors for a similar time span, and geothermal energy could satisfy some requirements for a long time. And finally, there may be fusion. It would be unlikely that any one of the available options should play a really dominant role. Rather, we should expect to be using an energy mix, just as we do now, with each energy source supplying the requirements which it can satisfy in the most suitable way, and solar energy should play an important role in this long-range future.  相似文献   

THE THREAT OF ANTI-VIVISECTION     

Wolf AV 《Science (New York, N.Y.)》1945,102(2641):160

  相似文献   

Saving the small farm: Agriculture in roman literature     

Alfred Wolf 《Agriculture and Human Values》1987,4(2-3):65-75

Roman agriculture suffered traumatic changes during the 2nd century B.C. The traditional farmers who tilled their few acres and served family, gods and community were being squeezed out by large estate owners using slaves for investment farming. Politicians, scholars and poets tried to revive the ancestoral rustic life. In 133 B.C. the Gracchi legislated land reform to relieve the distress of the farmer soldiers who had won the empire. Although their efforts led to political confrontation that deteriorated into civil war, programs for the traditional farm became a permanent part of government policy from the late Republic until the end of the empire in 476 A.D. Scholars and poets made a contribution to the revival of agriculture with knowledge for improving the farm and by encouraging an agrarian mentality. The agricultural manuals (e.g. Cato (c. 150 B.C.), Varro (c. 50 B.C), and Columella (c.65 A.D.), defined the nature of the desirable farm and gave practical advice. Profit was the goal, but good farming practices made for pleasure and virtue as well. The image of the ancestoral farmer was perpetuated as was the notion that farming was the only honorable and respectable occupation for a Roman gentleman. In the Augustan Age (34 B.C.—14 A.D.) poets were encouraged by the government to adopted a rustic theme in hopes it would stimulate a return to the land and aid in the rebirth of Rome and Romans. In the GeorgicsVirgil begins with the practical details of farming, but uses myth and philosophy to explore the nature and meaning of life. He admits that Jove made life perilous. But Jove also gave man the art of agriculture and with hard work man could know the pleasure of a simple, virtuous, productive life. Horace directed his poetry against the allure of city life and in praise of rustic living. Epicureanism and Stoicism, in the guise of life on the farm, could show that although fate was unpredictable, the world was orderly and, if one recognized and accepted its limits, one could make a garden of the world and live a simple but happy life. By 300 A.D. Rome missed the peasant-farmer-soldier and by the 470's life had returned to an agrarian condition. Bishop Sidonius, trying to furnish meaning and perspective for the emerging new age, resorted to the Roman agricultural traditions still cherished as that world disappeared.  相似文献   

Community ordering and niche width     

Shugart HH  McNaughton SJ  Wolf LL 《Science (New York, N.Y.)》1970,170(3964):1335

  相似文献   

Transmission of methicillin resistant Staphylococcus aureus among pigs during transportation from farm to abattoir     

Els M. Broens  Elisabeth A.M. Graat  Peter J. Van Der Wolf  Arjen W. Van De Giessen  Mart C.M. De Jong 《Veterinary journal (London, England : 1997)》2011,189(3):302-305

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs at abattoirs is higher than in pigs sampled on farms. This study investigated whether MRSA negative pigs can become MRSA positive during transportation from the farm to the abattoir after exposure to other pigs and environmental sources of MRSA. Nasal swabs were collected from four batches of pigs during loading at the farm, on arrival at the abattoir and after stunning. Environmental wipes were taken from lorries after transporting pigs and from lairages after holding pigs. All pigs (n = 117) tested MRSA negative before transportation. On arrival at the abattoir, 12/117 (10.3%) pigs in two batches tested MRSA positive. In lorries that tested positive after transportation, the prevalence of MRSA positive pigs was 21.1%, whereas no MRSA was detected in pigs that had been transported in lorries that tested negative after transportation. At stunning, all batches and 70/117 (59.8%) pigs tested MRSA positive. Pigs can become MRSA positive in the short period of time during transportation from the farm to stunning at the abattoir.  相似文献   

Perceptions of risk, risk aversion, and barriers to adoption of decision support systems and integrated pest management: an introduction     

Gent DH  De Wolf E  Pethybridge SJ 《Phytopathology》2011,101(6):640-643

Rational management of plant diseases, both economically and environmentally, involves assessing risks and the costs associated with both correct and incorrect tactical management decisions to determine when control measures are warranted. Decision support systems can help to inform users of plant disease risk and thus assist in accurately targeting events critical for management. However, in many instances adoption of these systems for use in routine disease management has been perceived as slow. The under-utilization of some decision support systems is likely due to both technical and perception constraints that have not been addressed adequately during development and implementation phases. Growers' perceptions of risk and their aversion to these perceived risks can be reasons for the "slow" uptake of decision support systems and, more broadly, integrated pest management (IPM). Decision theory provides some tools that may assist in quantifying and incorporating subjective and/or measured probabilities of disease occurrence or crop loss into decision support systems. Incorporation of subjective probabilities into IPM recommendations may be one means to reduce grower uncertainty and improve trust of these systems because management recommendations could be explicitly informed by growers' perceptions of risk and economic utility. Ultimately though, we suggest that an appropriate measure of the value and impact of decision support systems is grower education that enables more skillful and informed management decisions independent of consultation of the support tool outputs.  相似文献   

PCR-based detection of sunflower white blister rust (<Emphasis Type="Italic">Pustula helianthicola</Emphasis> C. Rost &; Thines) in soil samples and asymptomatic host tissue     

Otmar Spring  Thines Marco  Stefanie Wolf  Reinhard Zipper 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):519-527

Sequencing of partial cox2 (part of the mitochondrial cytochrome-c-oxydase (COX) gene) was performed with samples from the oomycete genus Pustula, the white blister rusts of Asteraceae and related families. Sequence comparison uncovered several single nucleotide polymorphisms (SNPs) between P. spinulosa and host specific strains of Pustula isolated from Senecio vulgaris, Tragopogon pratensis and cultivated sunflower, Helianthus annuus. Based on these differences, specific primers were designed for PCR-based detection of white blister rust strains pathogenic to sunflower. The specificity of the primers was confirmed by cross testing with DNA from various oomycetes occurring in the same locality. The limit of detection for DNA of P. helianthicola was 10 pg. This allowed detection with DNA from single sporangia and single oospores. The PCR-based experiments allowed detection of the presence of sunflower white blister rust in soil samples from fields on which infected plants had been cultivated several months before. Moreover, the molecular tools were successfully applied to trace the pathogen in asymptomatic tissue of infected plants, demonstrating the systemic nature of Pustula on sunflower.  相似文献   

WOFOST: a simulation model of crop production   总被引：20，自引：0，他引：20  

C.A. van  Diepen J. Wolf  H. van  Keulen C. Rappoldt 《Soil Use and Management》1989,5(1):16-24

Abstract. The WOFOST simulation model is a tool for analysing the growth and production of field crops under a wide range of weather and soil conditions. Such an analysis is important first to assess to what extent crop production is limited by the factors of light, moisture and macro-nutrients, and second to estimate what improvements are possible. The theoretical concept of a production situation, as modelled by WOFOST, is explained, as is the hierarchy of potential production and water-limited and nutrient-limited production situations in the analysis. The organization of the computer files in the model, the structure of the FORTRAN source program and the available standard sets of data are described briefly.  相似文献   

Metabolism of ronidazole (1-methyl-5-nitroimidazol-2-ylmethyl carbamate)     

C Rosenblum  N R Trenner  R P Buhs  C B Hiremath  F R Koniuszy  D E Wolf 《Journal of agricultural and food chemistry》1972,20(2):360-371

  相似文献   

Biochemical characterization of amandin,the major storage protein in almond (Prunus dulcis L.)   总被引：1，自引：0，他引：1  

Sathe SK  Wolf WJ  Roux KH  Teuber SS  Venkatachalam M  Sze-Tao KW 《Journal of agricultural and food chemistry》2002,50(15):4333-4341

The almond major storage protein, amandin, was prepared by column chromatography (amandin-1), cryoprecipitation (amandin-2), and isoelectric precipitation (amandin-3) methods. Amandin is a legumin type protein characterized by a sedimentation value of 14S. Amandin is composed of two major types of polypeptides with estimated molecular weights of 42-46 and 20-22 kDa linked via disulfide bonds. Several additional minor polypeptides were also present in amandin. Amandin is a storage protein with an estimated molecular weight of 427,300 +/- 47,600 Da (n = 7) and a Stokes radius of 65.88 +/- 3.21 A (n = 7). Amandin is not a glycoprotein. Amandin-1, amandin-2, and amandin-3 are antigenically related and have similar biochemical properties. Amandin-3 is more negatively charged than either amandin-1 or amandin-2. Methionine is the first essential limiting amino acid in amandin followed by lysine and threonine.  相似文献