The Gibbs Paradox Revisited

The Gibbs paradox has frequently been interpreted as a sign that particles of the same kind are fundamentally indistinguishable; and that quantum mechanics, with its identical fermions and bosons, is indispensable for making sense of this. In this article we shall argue, on the contrary, that analysis of the paradox supports the idea that classical particles are always distinguishable. Perhaps surprisingly, this analysis extends to quantum mechanics: even according to quantum mechanics there can be distinguishable particles of the same kind. Our most important general conclusion will accordingly be that the universally accepted notion that quantum particles of the same kind are necessarily indistinguishable rests on a confusion about how particles are represented in quantum theory.Comment: to appear in Proceedings of "The Philosophy of Science in a European Perspective 2009

The effect of alternative irrigation management on micronutrient availability and GHG emissions in paddy soils

In a context of increasing food demands and a changing climate causing decreased water availability, alternative irrigation management (AIM) in paddy rice production is broadly being applied in Asia and other rice producing regions. In combination with efficient soil fertilization management, AIM aims at sustainably intensifying rice production while using less water. However, AI ’s increasing popularity may impose a trade-off from saving water to increasing GHG emissions (mainly of N2O) and affecting micronutrient availability in paddy soils. The general objective of this research was to assess the effect of AIM on micronutrient availability (Fe, Mn, Cu and Zn), GHG emissions and other relevant related soil and plant parameters. Soils from the plough layer of 3 Philippine farmers’ paddy fields with differing soil textures were collected for a greenhouse pot experiment. The samples were subjected to three commonly applied irrigation techniques, differing in the number and duration of draining events along the growing season: continuous flooding (CF), alternate wetting and drying (AWD) and mid-season drainage (MSD). Micro-nutrient availability to plants (DTPA extracts), GHG emissions (CH4, CO2 and N2O) and various biogeochemical parameters such as exchangeable NH4, dissolved OC (DOC), pH and soil redox potential and temperature were assessed during the entire growing season. Other plant related parameters (plant height, tiller and leaf number and mean biomass) were measured during harvest. Results indicate a reduced availability of Fe and Mn under an AWD compared to CF regime, particularly during the reproductive growth phase of the rice plants. During the earlier growth stages, however, Cu and Zn concentrations show an opposite trend for all soil types. As for mineral nitrogen concentrations, a strong decline was observed for all three soil types, regardless of the water management applied. By the end of the ripening stage, contents close to zero kg ha-1 were generally observed, probably due to enhanced volatilization of NH3 towards the end of the growing season, caused by the high ambient temperatures in the greenhouse. DOC concentrations did not show clear differences between any of the treatments. CH4 fluxes were surprisingly high at the onset of the growing season but they quickly declined within a time span of three weeks. Due to considerably low CH4 emission values during the rest of the growing season (not exceeding 10 mg m-2 d-1), no significant differences could be observed between the three irrigation treatments. Analyses of measured N2O and CO2 emissions are still in progress. Rice plant height, tiller and leaf number and mean biomass were all favoured by CF when compared to AWD management in all three soils. The above mentioned results indicate that while water saving management in rice farming reduces emissions of CH4, it may as well limit micro-nutrient availability for rice plant uptake, and in our pot experiment also crop growth

The Structure of the Retail and Service Industries of Jefferson County

The intent of this study is to review the current strengths and weaknesses of the retail and services industries of Jefferson County. We use historical data to look for overall trends and 2004 county sales tax data to provide detailed insights.

Atmospheric electricity/meteorology analysis

This activity focuses on Lightning Imaging Sensor (LIS)/Lightning Mapper Sensor (LMS) algorithm development and applied research. Specifically we are exploring the relationships between (1) global and regional lightning activity and rainfall, and (2) storm electrical development, physics, and the role of the environment. U.S. composite radar-rainfall maps and ground strike lightning maps are used to understand lightning-rainfall relationships at the regional scale. These observations are then compared to SSM/I brightness temperatures to simulate LIS/TRMM multi-sensor algorithm data sets. These data sets are supplied to the WETNET project archive. WSR88-D (NEXRAD) data are also used as it becomes available. The results of this study allow us to examine the information content from lightning imaging sensors in low-earth and geostationary orbits. Analysis of tropical and U.S. data sets continues. A neural network/sensor fusion algorithm is being refined for objectively associating lightning and rainfall with their parent storm systems. Total lightning data from interferometers are being used in conjunction with data from the national lightning network. A 6-year lightning/rainfall climatology has been assembled for LIS sampling studies

Commensurate Nb2Zr5O15: Accessible Within the Field Nb2ZrxO2x+5 After All

Doped niobium zirconium oxides are applied in field-effect transistors and as special-purpose coatings. Whereas their material properties are sufficiently known, their crystal structures remain widely uncharacterized. Herein, we report on the comparably mild sol–gel synthesis of Nb2Zr5O15 and the elucidation of its commensurately modulated structure via neutron diffraction. We describe the structure using the most appropriate superspace as well as the convenient supercell approach. It is part of an α-PbO2-homeotypic field with the formula Nb2ZrxO2x+5, which has previously been reported only for x ≥ 5.1, and is closely related to the structure of Hf3Ta2O11. The results, supported by X-ray diffraction and additional synthesis experiments, are contextualized within the existing literature. Via the sol–gel route, metastable Nb–Zr–O compounds and their heavier congeners are accessible that shed light on possible structures of these commercially utilized materials.DFG, 198634447, SPP 1613: Regenerativ erzeugte Brennstoffe durch lichtgetriebene Wasserspaltung: Aufklärung der Elementarprozesse und Umsetzungsperspektiven auf technologische KonzepteTU Berlin, Open-Access-Mittel - 201

untitled, ambiguity and architecture

Thesis: M. Arch., Massachusetts Institute of Technology, Department of Architecture, May, 2020Cataloged from PDF version of thesis.Includes bibliographical references (page 151).This thesis seeks to expand Robert Venturi's concept of ambiguity in architecture to include meanings that, extending beyond the formal and semiotic, are rooted in narrative. It takes as a precedent the work of Larry Sultan and Mike Mandel, two artists whose book Evidence explores both formal and narrative ambiguity in photography. This expanded definition of ambiguity evokes the mercurial and conflicting thoughts, feelings, facts, and memories that are at the core of architectural experience yet remain conspicuously absent from contemporary discourse. untitled consists of four books that collectively and equally constitute the thesis. Each book can be intepereted independently or in dialogue with its companions. Braddock, Pennsylvania is a steel town downriver from Pittsburgh, in Allegheny County. The town's dualities are manifest in the narrative tensions between past and present, mind and body, growth and decay.It is home to the first Carnegie Free Library in the US as well as to the Edgar Thomson Steel Works - one of America's earliest, and still-operating, steel mills. Braddock Avenue runs the length of the town and serves as a mile-long Main Street that encompasses the breadth of the town's vernacular American architectural history. The thesis takes as its site the empty lots along Braddock Ave. that now make up nearly half of the streetscape. Without speculating on the uncertain future of the town's industry, the project engages the divergent narratives of the town by imagining a renewal of Braddock Avenue. A formal strategy of mirroring the existing urban fabric is deployed in an act analogous to the production of photographic images. Where possible, existing buildings are mirrored onto adjacent empty lots; in this act each building is isolated, duplicated, and transformed.The buildings' bounds are reproduced inversely while their materiality and tectonic languages are replaced by new mass timber structural systems and surfaces. Together with these mirrored forms, the sharply differing color of light reflected on these new materials evokes divergent memories and feelings associated with the work of photographers like Diane Arbus and Stephen Shore, who capture the melancholy, peculiarities and optimism of American urban abjection. The dialectic between the town and the mill is represented by a new community center inserted at the heart of Braddock Avenue, radically skewed on an open site adjacent to the Carnegie Library. This singular anomaly is a distorted mirror of the building forms found in the Edgar Thomson Steel Mill, representing the capacity of mirroring to make architecture participate in an expanding field.The new building's typology, materiality, tectonics, and programs collectively evoke divergent readings that are at once historic and speculative, sacred and profane.by Dennis Steven Kosovac.M. Arch.M.Arch. Massachusetts Institute of Technology, Department of Architectur

The Influence of Workplace Stressors, Resources and Perceptions on Work-to-Family Spillover: An Application of the Double ABCX Model

Changes in the American workforce have raised concern over the interface between family and work. The responsibilities and frustrations of the work domain frequently spill over to the family domain and vice versa. The purpose of this research has been to investigate the influence of workplace stressors, resources, and perceptions on subsequent negative work-to-family spillover. The theoretical direction for the study stems from a modified application of McCubbin and Patterson\u27s double ABCX model, which fits well into the larger spillover perspective. The data for the study came from 1992 National Study of the Changing Workforce [NSCW). A subsample of respondents who worked full-time, lived with another family member, and were not self-employed was used for the analysis. The final sample consisted of 598 respondents. The findings suggest that work-co-family spillover is more common for women than men. However, the workplace stressor and resources in this study had less direct influence on work-co-family spillover for women than for men. In shore, an adequate explanation of work-to-family spillover is likely more complex for women than for men. The findings also generally supported the theoretical model. That is, workplace stressors, workplace resources, and family perceptions generally had an effect on work-co-family spillover. Interestingly, formal workplace resources, such as family-friendly programs, had only a small effect on work-to-family spillover. However, exploring spillover from a family-co-work direction would have possibly yielded different results. Informal resources had only modest direct effects on work-to-family spillover, but indirect effects were practically important. General perception had the strongest direct effect on work-to-family spillover for both men and women

Law-Based Arguments and Messages to Advocate for Later School Start Time Policies in the United States

The increasing scientific evidence that early school start times are harmful to the health and safety of teenagers has generated much recent debate about changing school start times policies for adolescent students. Although efforts to promote and implement such changes have proliferated in the United States in recent years, they have rarely been supported by law-based arguments and messages that leverage the existing legal infrastructure regulating public education and child welfare in the United States. Furthermore, the legal bases to support or resist such changes have not been explored in detail to date. This article provides an overview of how law-based arguments and messages can be constructed and applied to advocate for later school start time policies in U.S. public secondary schools. The legal infrastructure impacting school start time policies in the United States is briefly reviewed, including descriptions of how government regulates education, what legal obligations school officials have concerning their students\u27 welfare, and what laws and public policies currently exist that address adolescent sleep health and safety. On the basis of this legal infrastructure, some hypothetical examples of law-based arguments and messages that could be applied to various types of advocacy activities (e.g., litigation, legislative and administrative advocacy, media and public outreach) to promote later school start times are discussed. Particular consideration is given to hypothetical arguments and messages aimed at emphasizing the consistency of later school start time policies with existing child welfare law and practices, legal responsibilities of school officials and governmental authorities, and societal values and norms

Land Tenure and the Management of Land Resources in Trinidad and Tobago

The potential of the agricultural sector in Trinidad and Tobago has not been realized in recent decades. The more productive land resources of the country are underutilized, while many of the more fragile ecosystems are in danger. This threatens to deny the country potential income from ecotourism as well as deprive future generations of a stable land, forest, and water base. The optimal use of the country's land resources requires a stable and secure tenure system defining land rights. The Government of the Republic of Trinidad and Tobago contracted the Land Tenure Center to carry out land rationalization studies, which are intended to assist in the preparation of an action plan to deal with the problems of the land tenure system. The result was the preparation of twenty-one studies, which have been organized into two LTC research papers. This first paper explores the nature and extent of tenure insecurities in both urban and rural contexts, with a focus on agricultural land tenure problems. Several hypotheses are advanced concerning the possible constraints that legal and social insecurity of tenure pose for the future development of the country. Also explored are the environmental problems that past tenure regimes have helped generate, and what might comprise a strategy for protecting fragile ecosystems. A second paper (LTC Research Paper 116) will dig more deeply into the institutional and historical roots of the tenure insecurity problems. A final report presented to the government in August 1992 described a Land Rationalization and Development Programme, which was derived from the twenty-one studies carried out by LTC.Land Economics/Use,

Trade booms, trade busts and trade costs

What has driven trade booms and trade busts in the past and present? We derive a micro-founded measure of trade frictions from leading trade theories and use it to gauge the importance of bilateral trade costs in determining international trade flows. We construct a new balanced sample of bilateral trade flows for 130 country pairs across the Americas, Asia, Europe, and Oceania for the period from 1870 to 2000 and demonstrate an overriding role for declining trade costs in the pre-World War I trade boom. In contrast, for the post-World War II trade boom we identify changes in output as the dominant force. Finally, the entirety of the interwar trade bust is explained by increases in trade costs