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The current status of galaxy formation

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Research in Astronomy and Astrophysics 2012年第8期12卷 917-946页

作者： joseph Silk Gary A.Mamon Institut d'Astrophysique de Paris (UMR 7095:CNRS&UPMC) 98 bis Boulevard AragoParis 75014France Department of Physics and Astronomy 3701 San Martin DriveThe Johns Hopkins UniversityBaltimore MD 21218USA Beecroft Institute of Particle Astrophysics and Cosmology 1 Keble RoadUniversity of OxfordOxford OX1 3RHUK

Understanding galaxy formation is one of the most pressing issues in cos- mology. We review the current status of galaxy formation from both an observational and a theoretical perspective, and summarize the prospects ... 详细信息

关键词： galaxy: formation -- galaxies: evolution -- galaxies: star formation --galaxies: active

Supporting farmer-managed irrigation systems in the Shigar valley, Karakorum： Role of the government and Aga Khan Rural Support Programme

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Journal of Mountain Science 2017年第10期14卷 2064-2081页

作者： joseph K.W.HILL Department of Rural Management Xavier Institute of Social Sciences (XISS) Dr Gamil Bulcke Path Post Box 7 Ranchi- 834001 India

Farmer-managed irrigation systems(FMIS) in the high altitude valleys of the Karakorum,Pakistan, continue to be managed effectively despite increased pressure on the social arrangements that sustain them. Colonial era records shows that over a century ago government agencies undertook irrigation support projects. In the past three decades,government agencies and the non-government agency Aga Khan Rural Support Programme(AKRSP), which channels foreign funds into the region, have actively engaged in the provision of irrigation support. This article seeks to explore whether such projects support or undermine farmer-managed irrigation systems and the complex institutional arrangements that underpin them. Field research using ethnographic and participatory methods was conducted in spring 2013 in the upper Shigar valley, Skardu district, GilgitBaltistan. The findings show that irrigation development is a political activity that involves village-based actors, religious leaders, local politicians,and government and non-government *** agencies operate in a largely top-down,engineering mode, their larger projects limited to villages suffering water scarcity. The local government provides small funds for renovation work of FMIS,though allocation of funds is highly politicized. Nongovernment agencies, for a variety of reasons including donor-funding cycles, apply a one-size-fitsall ‘participatory' model in an attempt to socially engineer rules and institutions. In communities divided by factionalism the use of such external models that stress formation of committees are unlikely to yield positive results, and could instead contribute to undermining the very systems they seek to support. This research argues that irrigation interventions should take care to build upon the rich and complex social arrangements that have sustained FMIS through the centuries.

关键词： Farmer-managed irrigation systems Institutional arrangements Government Aga Khan Rural Support Programme Shigar valley Karakorum

Simulation of Desert-Scrub Growth: A Forcing to Warmer and More Pluvial Climate

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Advances in Atmospheric Sciences 1992年第4期9卷 441-450页

作者： joseph Otterman Tel Aviv University Ramat Aviv Israel present address NASA/Goddard Space Flight Center Code 911 Greenbelt MD 20771 U. S. A.esert-fringe vegetation growing over bright sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub these shrubs form a predominantly vertical clumps protruding from the soil-level thereby significantly increasing the coefficient of turbulent heat transfer from the surface. The impact on global and desert-belt climate of changes in these two surface characteristics was simulated by a multi-layer energy balance tnodel. Evaluated only as a forcing to a further climatic change (that is without accounting for any possible feedbacks) the results are: if vegetation (such as apparently existed under the warmer climate of 6000 BP ) grows over large areas in the arid currently bare-soil regions the annual Northern Hemisphere surface temperature increases by 0.7t (by 0.6'C in July ) the surface temperature over land in the 20-30°N zone increases by 0.9℃ in both the annual and the July means and the land-ocean annual temperature contrast in this zone increases by 0.25℃(0.2° in July). These results represent the combined influence of the reduction in the surface albedo and of the increase in the coefficient of turbulent heat transfer. In the desert-belt zones the increase in the transfer coefficient sharply reduces the land temperature and the land-ocean temperature contrast from the values produced by the albedo change alone. This reduction must be attributed to the increased land-to-ocean circulation (which our model does not evaluate explicitly). Considering that a stronger circulation (resulting from land-ocean temperature contrast) generally forces a higher rainfall the vegetation which emerged in the arid regions during the post-glacial optimum should be considered a significant positive feedback towards a still warmer and also a more pluvial climate. Our study may have implications for the 21st century if the global warming expected from the

Desert-fringe vegetation growing over bright, sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub, these shrubs form a predominantly vertical clumps protruding from the soil-level, thereby significantly increasing the coefficient of turbulent heat transfer from the surface. The impact on global and desert-belt climate of changes in these two surface characteristics was simulated by a multi-layer energy balance tnodel. Evaluated only as a forcing to a further climatic change (that is, without accounting for any possible feedbacks) the results are: if vegetation (such as apparently existed under the warmer climate of 6,000 BP ) grows over large areas in the arid, currently bare-soil regions, the annual Northern Hemisphere surface temperature increases by 0.7t (by 0.6'C in July ), the surface temperature over land in the 20-30°N zone increases by 0.9℃ in both the annual and the July means, and the land-ocean annual temperature contrast in this zone increases by 0.25℃(0.2° in July). These results represent the combined influence of the reduction in the surface albedo and of the increase in the coefficient of turbulent heat transfer. In the desert-belt zones, the increase in the transfer coefficient sharply reduces the land temperature and the land-ocean temperature contrast from the values produced by the albedo change alone. This reduction must be attributed to the increased land-to-ocean circulation (which our model does not evaluate explicitly). Considering that a stronger circulation (resulting from land-ocean temperature contrast) generally forces a higher rainfall, the vegetation which emerged in the arid regions during the post-glacial optimum should be considered a significant positive feedback towards a still warmer, and also a more pluvial, climate. Our study may have implications for the 21st century, if the global warming expected from the enhanced greenhouse effects is accompanied by increased precipitation over the

关键词： Simulation of Desert-Scrub Growth A Forcing to Warmer and More Pluvial Climate

Changes in Streamflow Regime Due to Anthropogenic Regulations in the Humid Tropical Western Ghats, Kerala State, India

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Journal of Mountain Science 2015年第2期12卷 456-470页

作者： ABE George ERINJERY joseph James Centre for Water Resources Development and Management Sub centre Water Institute Karunya University

Regulation of streamflow by a reservoir creates a flow regime much different from the preimpoundment period flow regime. Hydro-Electric Projects(HEPs) commissioned in the Western Ghat regions of the Kerala State, India during the last four decades caused considerable changes in the flow regimes of the rivers of the Kerala State in southwest India. In this paper, the Indicators of Hydrologic Alteration(IHA) approach proposed by Richter et al.(1996) is used to analyze flow regime changes in the Periyar and Muvattupuzha Rivers, due to the construction of the Idukki(1976), Idamalayar(1987) and Lower Periyar(1997) HEPs in the high ranges of the Western Ghats. Normal rainfall years(annual rainfall values within mean ± 0.75 standard deviation limits) are only considered in the analysis to focus on hydrologic alterations due to human activities. The mean hydrologic alteration in the Periyar River(deviation from the pre-development hydrologic indicator values) after commissioning of three HEPs is 35%. Inter-basin water transfer after power generation from the Idukki HEP resulted in a higher discharge in the adjacent Muvattupuzha River, leading to considerable changes in the hydroenvironment(mean hydrologic alterations varying between 57 to 63%). IHA parameters showing hydrologic alterations above the 67 th Percentile werefurther analyzed. For each of the pre-construction hydrologic parameters ± 1 standard deviation from the mean is set as the upper and lower management target limits. The values of each IHA parameter beyond these targets are considered as nonattainment. Considerable hydrologic alterations are observed, especially for low flows in both basins. Inter-basin transfer induced larger changes in flow parameters compared to intra-basin regulations. The study shows that under a proper water release and diversion scheme, the non-attainment of IHA parameters(values fall beyond the target limits) can be reduced. The findings of the study will be greatly beneficial to reg

关键词： Range variability approach Hydroelectric projects Humid tropics Flow regime changes Inter-basin regulation Intra-basin regulation

Soil carbon stock and emission: estimates from three land-use systems in Ghana

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Ecological Processes 2021年第1期10卷 157-169页

作者： joseph Anokye Vincent Logah Andrews Opoku Department of Crop and Soil Sciences Kwame Nkrumah University of Science and Technology(KNUST)KumasiGhana

Background:Land-use systems that sequester carbon and reduce CO_(2) emissions are key in the global mitigation strategies of climate *** gas emission from agro-ecosystems in sub-Saharan Africa is little ***,we quantified soil carbon stock(SCS)and CO_(2) emissions from three land-use systems *** land,oil palm plantation and forestland in the semi-deciduous forest zone of ***:Soil organic carbon concentration at the 0–15 cm layer in the forestland was 62 and 23%greater than that in the arable land and palm plantation,*** SCS along the 1.0-m profile was 108.2,99.0 and 73.5 Mg ha^(−1) in the forestland,palm plantation and arable land,*** land emitted 30–46%more CO_(2) than palm plantation and *** the dry season,CO_(2) emissions were respectively 0.93,0.63 and 0.5 kg ha^(−1) h−1 from the arable land,palm plantation and *** relationships were observed between CO_(2) emissions and SCS,soil temperature,and *** SCS greatly influenced CO_(2) emission in the dry season more than in the wet season in the relatively higher carbon-input systems(forestland and palm plantation).Soil temperature accounted for more than 55%of CO_(2) emissions in both seasons,which has implications in the era of rising global ***:The study provides relevant information on carbon storage abilities of the three land-use types in tropical climate and calls for drastic climate change actions to reduce degradation of forest cover and soil disturbance in agro-ecosystems in sub-Saharan Africa.

关键词： Arable land Carbon dioxide emission Climate change Soil moisture Soil temperature Sub-Saharan Africa

Ultraviolet discharges from a radio-frequency system for potential biological/chemical applications

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Chinese Physics B 2017年第8期26卷 157-161页

作者： joseph Ametepe Sheng Peng Dennis Manos Georgia Gwinnett College School of Science and TechnologyLawrenceville-GA 30078USA EXFO Mississaugaon Canada L5N 6H7 College of William and Mary Department of PhysicsWilliamsburgVA 2385USA

In this work, we describe a new electrode-less radio-frequency（RF） excitation technique for generating excimers in the vacuum ultraviolet（VUV） and ultraviolet（UV） spectral regions for potential biological/chemical applications. Spectra data of Xe~＊_2, XeI~＊, and KrI~＊ generated by this new technique are presented. Optical efficiency of the lamp system ranges from 3% to 6% for KrI~＊, 7% to 13% for XeI~＊, and 15% to 20% for Xe~＊_2. Also, results of irradiating E-coli with XeI~＊discharge from this lamp system is presented to show one of the promising applications of such electrode-less *** new RF lamp system offers an interesting addition to the already existing technologies for generating VUV and UV light for various biological, physical, and chemical processes especially those requiring large area for high productivity.

关键词： radio-frequency ultraviolet light Xe2* XeI* KrI* excimers escherichia coli

EVOLUTION AND INTERACTION OF δ-WAVES IN THE ZERO-PRESSURE GAS DYNAMICS SYSTEM

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Acta Mathematica Scientia 2024年第5期44卷 1801-1836页

作者： Abhishek DAS K.T.joseph Centre for Data Science Institute of Technical Education and Research(ITER)Siksha‘O’Anusandhan(Deemed to be University)BhubaneswarOdisha751030India Centre for Applicable Mathematics Tata Institute of Fundamental ResearchSharada NagarBangalore560065KarnatakaIndia

Evolution and interaction of plane waves of the multidimensional zero-pressure gas dynamics system leads to the study of the corresponding one dimensional *** this paper,we study the initial value problem for one dimensional zero-pressure gas dynamics *** the first equation is the Burgers equation and the second one is the continuity *** consider the solution with initial data in the space of bounded Borel *** we prove a general existence result in the algebra of generalized functions of *** we study in detail special solutions withδ-measures as initial *** study interaction of waves originating from initial data concentrated on two point sources and interaction with classical shock/rarefaction *** gives an understanding of plane-wave interactions in the multidimensional *** use the vanishing viscosity method in our analysis as this gives the physical solution.

关键词： zero-pressure gas dynamics delta-waves interaction of waves

Calculation of First Sound Speed in Liquid Helium

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Chinese Physics Letters 1999年第4期16卷 276-278页

作者： PAO Lu joseph P.Foy Department of Physics and Astronomy Arizona State UniversityTempeArizona 85287USA

The speed of first sound in liquid helium II is calculated quantum *** calculation is made by using a modified version of Brueckner and Sawada’s method[***.106(1959)1128]and is based on the postulate that the hard co... 详细信息

关键词： quantum Sound sound

Chemical exposures and suspected impacton Gulf War Veterans

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Military Medical Research 2023年第5期10卷 577-586页

作者： Rami Elhaj joseph M.Reynolds Center for Cancer Biology Immunology and InfectionChicago Medical SchoolRosalind Franklin University of Medicine and ScienceNorth ChicagoIL 60064USA

Gulf War Illness(GWI) encompass a spectrum of maladies specific to troops deployed during the Persian Gulf War(1990–1991). There are several hypothesized factors believed to contribute to GWI, including(but not limited to)exposures to chemical agents and a foreign environment(e.g., dust, pollens, insects, and microbes). Moreover, the inherent stress associated with deployment and combat has been associated with GWI. While the etiology of GWI remains uncertain, several studies have provided strong evidence that chemical exposures, especially neurotoxicants,may be underlying factors for the development of GWI. This mini style perspective article will focus on some of the major evidence linking chemical exposures to GWI development and persistence decades after exposure.

关键词： Gulf War Illness(GWI) Sarin Neuroinfammation Organophosphate(OP)