cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Cosmic evolution of dark energy in a generalized Rastall gravity
Creators: name: Lin, Kai
name: Qian, Wei-Liang
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work, we propose a scheme for cosmic evolution in a generalized Rastall gravity. In our approach, the role of dark energy is taken by the non-conserved sector of the stress energy-momentum tensor. The resultant cosmic evolution is found to naturally consists of three stages, namely, radiation dominated, ordinary matter dominated, as well as dark energy and dark matter dominated eras. Furthermore, for the present model, it is demonstrated that the eventual fate of the Universe is mostly insensitive to the initial conditions, in contrast to the standard $Λ$CDM model. In particular, the solution displays the properties of a dynamic attractor, which is reminiscent of quintessence and k-essence models. Subsequently, the cosmic coincidence problem is averted. The amount of deviation from a conserved stress energy-momentum tensor is shown to be more remarkable during the period when the dark energy evolves more rapidly. On the other hand, the conservation law is largely restored for the infinite past and future. The implications of the present approach are addressed.
description: Accepted by the European Physical Journal C
Public Attitudes towards Agricultural Biotechnology
Creators: name: Hoban, Thomas J.
name: Hoban, Thomas J.
Publisher: name: Unknown
Year: 2004
Subjects: subject: Research and Development/Tech Change/Emerging Technologies
subject: Agricultural Biotechnology
subject: FOS: Agricultural biotechnology
subject: Public Opinion
subject: Consumer Acceptance.

description: The full benefits of agricultural biotechnology will only be realized if consumers and food manufacturers consider it safe and beneficial. Although few internationally comparable public opinion surveys have been conducted on this issue, the available evidence suggests that public attitudes differ sharply both between and within countries and are evolving over time. Consumer attitudes have been studied in the United States and Europe for more than a decade. This research is reviewed along with the available data from Latin America, Asia and Africa. Results from the largest internationally comparable public opinion survey on agricultural biotechnology to date are highlighted.
description: FAO Document Repository: http://www.fao.org/3/ae064e/ae064e00.pdf
On the frequency of close binary systems among very low-mass stars and brown dwarfs
Creators: name: Maxted, P. F. L.
name: Jeffries, R. D.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have used Monte Carlo simulation techniques and published radial velocity surveys to constrain the frequency of very low-mass star (VLMS) and brown dwarf (BD) binary systems and their separation (a) distribution. Gaussian models for the separation distribution with a peak at a = 4 au and 0.6 =< sigma(log(a/au)) =< 1.0 correctly predict the number of observed binaries, yielding a close (a<2.6 au) binary frequency of 17-30 per cent and an overall VLMS/BD binary frequency of 32-45 per cent. We find that the available N-body models of VLMS/BD formation from dynamically decaying protostellar multiple systems are excluded at >99 per cent confidence because they predict too few close binary VLMS/BDs. The large number of close binaries and high overall binary frequency are also very inconsistent with recent smoothed particle hydrodynamical modelling and argue against a dynamical origin for VLMS/BDs.
description: Accepted for publication in MNRAS letters. 5 pages, 2 figures
Intracellular Electrochemical Nanomeasurements Reveal that Exocytosis of Molecules at Living Neurons is Subquantal and Complex
Creators: name: Larsson, Anna
name: Majdi, Soodabeh
name: Oleinick, Alexander
name: Svir, Irina
name: Dunevall, Johan
name: Amatore, Christian
name: Ewing, Andrew
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Biological sciences

description: Since the early work of Bernard Katz, the process of cellular chemical communication via exocytosis, quantal release, has been considered to be all or none. Recent evidence has shown exocytosis to be partial or 'subquantal' at single-cell model systems, but there is a need to understand this at communicating nerve cells. Partial release allows nerve cells to control the signal at the site of release during individual events, where the smaller the fraction released, the greater the range of regulation. Here we show that the fraction of the vesicular octopamine content released from a living Drosophila larval neuromuscular neuron is very small. The percentage of released molecules was found to be only 4.5% for simple events and 10.7% for complex (i.e., oscillating or flickering) events. This large content, combined with partial release controlled by fluctuations of the fusion pore, offers presynaptic plasticity that can be widely regulated. Two works published in 2010 suggested that the Katz principle, [1] was incorrect for all-or-none release and that only part of the chemical load of vesicles was released during exocytosis, at least as measured as a full spike during amperometry. [2] The combination of electrochemical methods to measure both release and vesicle content in 2015 added a wealth of information to support the concept of partial release in exocytosis. [3] Additionally, this has recently been supported by work with TIRF microscopy showing 'subquantal' release from vesicles in adrenal chromaffin cells and using super-resolution STED microscopy. [4] It appears that the full event generally involves release of only part of the load of chemical messenger in single-cell model systems like adrenal chromaffin and PC12 cells. Is this also true at living neurons in a nervous system and to what extent? To answer this critical question, we quantified the number of octopamine molecules in the neuromuscular neurons of Drosophila larvae by adapting an amperometric technique developed in our
Numerical study on a disordered model for DNA denaturation transition
Creators: name: Coluzzi, Barbara
Publisher: name: arXiv
Year: 2005
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We study numerically a disordered version of the model for DNA denaturation transition (DSAW-DNA) consisting of two interacting SAWs in 3d, which undergoes a first order transition in the homogeneous case. The two possible values eAT and eGC of the interactions between base pairs are taken as quenched random variables distributed with equal probability along the chain. We measure quantities averaged over disorder such as the energy density, the specific heat and the probability distribution of the loop lengths. When applying the scaling laws used in the homogeneous case we find that the transition seems to be smoother in presence of disorder, in agreement with general theoretical arguments. Nevertheless we can not rule out the possibility of a still first order transition.
description: Latex, 25 pages including 12 postscript figures, published revised version (discussion enlarged)
Metric of a tidally distorted, nonrotating black hole
Creators: name: Poisson, Eric
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The metric of a tidally distorted, nonrotating black hole is presented in a light-cone coordinate system that penetrates the event horizon and possesses a clear geometrical meaning. The metric is expressed as an expansion in powers of r/R << 1, where r is a measure of distance from the black hole and R is the local radius of curvature of the external spacetime; this is assumed to be much larger than M, the mass of the black hole. The metric is calculated up to a remainder of order (r/R)^4, and it depends on a family of tidal gravitational fields which characterize the hole's local environment. The coordinate system allows an easy identification of the event horizon, and expressions are derived for its surface gravity and the rates at which the tidal interaction transfers mass and angular momentum to the black hole.
description: 4 pages. Final version, as it will appear in Physical Review Letters
Conflicts, Rural Development and Food Security in West Africa
Creators: name: Flores, Margarita
name: Flores, Margarita
Publisher: name: Unknown
Year: 2004
Subjects: subject: Food Security and Poverty
subject: West Africa
subject: Conflict
subject: Food Security
subject: Crisis
subject: Hunger

description: This paper examines food security in the context of conflict in West Africa. The analysis developed in the paper recognises the importance of defining conflict type and the trends in conflict so that conflict and post-conflict policies may be implemented. The relationship between food security and conflict is analysed. Whilst conflict exacerbates food security, food insecurity can itself fuel conflict. Strategies designed to assist in post-war rehabilitation need to address key dimensions of food security: availability, access and stability. It is argued in this paper, that consideration of these three dimensions are necessary joint conditions in moving towards a reduction in the numbers of hungry. The cases of Sierra Leone and Liberia are examined to consider the nature of conflict and how food security is being addresses and the necessary policy implications after prolonged violent conflict. Ghana is examined as an analytical contrast to show that the absence of conflict is not a sufficient condition for growth and reduced hunger.
description: FAO Document Repository: http://www.fao.org/3/ae057e/ae057e00.pdf
MONITORAMENTO DE PARÂMETROS FÍSICO-QUÍMICOS NA AGRICULTURA
Creators: name: ANDRADE, E. E. S
name: NASCIMENTO, F. J. M.
Publisher: name: Zenodo
Year: 2024
Subjects: MONITORAMENTO
PARÂMETROS
AGRICULTURA

description: O resumo simplificado, intitulado "Monitoramento de Parâmetros Físico-Químicos na Agricultura", foi submetido ao III Congresso Brasileiro Online de Ensino, Pesquisa e Extensão em 2024, organizado pela Sociedade Brasileira de Eventos Científicos (SOBREC). O autor principal, Everson Eduardo da Silva Andrade, cuja referência de citação é "Andrade, E. E. S.", apresentou o trabalho com o objetivo de divulgar conhecimento e incentivar o pensamento científico sobre o Monitoramento de Parâmetros Físico-Químicos na Agricultura. O co-autor, Fernando Jeferson de Macedo Nascimento, contribuiu para a pesquisa, sendo sua referência de citação "Nascimento, F. J. M.". O evento busca conectar a divulgação científica, o ensino e a extensão acadêmica, visando atingir um amplo público interessado nessa temática.
MEETING THE KYOTO TARGET THROUGH CONSERVATION TILLAGE AND ITS IMPLICATION FOR NATURAL CAPITAL MAINTENANCE, PRODUCTION EFFICIENCY, AND SUSTAINABILITY
Creators: name: Paudel, Krishna P.
name: Lohr, Luanne
name: Paudel, Krishna P.
name: Lohr, Luanne
Publisher: name: Unknown
Year: 2000
Subjects: subject: Environmental Economics and Policy
subject: Productivity Analysis
subject: Kyoto protocol
subject: Carbon sequestration
subject: Natural capital
subject: Production efficiency
subject: Sustainability

description: According to Article 3.4 of the Kyoto Protocol, agricultural soil could be used as a sink for carbon sequestration and hence it may provide an alternative venue to sequester the greenhouse gas emission. US plans to reduce the carbon emission amount by seven percent below the 1990 level within the target date of 2008-2012. The major approaches to achieve the goal targeted by Kyoto Protocol in US are through fossil fuel tax and increasing forest area by afforestation. This means fossil fuel price will increase which will have a direct impact to conventional tillage cost. As a result farmers would be motivated to use less machinery operation in farming and hence may use conservation tillage in farming practices. Rather than cause and effect relationship created by fuel price increase, conservation tillage itself has been considered as a method suggested to increase carbon sequestration. We analyze the economic and environmental roles of conservation tillage in carbon sequestration. The use of conservation tillage helps to sequester carbon in the form of soil organic matter. We examined the potential of conservation tillage in sequestering carbon and its role in increasing soil natural capital and thus the productivity of soil. We then used the concept of production efficiency to calculate the benefits of soil carbon sequestration using sustainability criteria. The detail of carbon sequestration and soil natural capital buildup were demonstrated using conservation tillage practiced in cotton production in Georgia. Four systems of conservation tillage encompassing both chemical and organic source of plant nutrients were compared for their capacity to sequester carbon. Organic matter buildups were faster in a system with conservation tillage and organic sources of nutrient compared to conventional tillage. Result indicated that in a system with a slow buildup of natural capital, production efficiency was not significant. This has resulted the system to be unprofitable in the short run and unsustainable in the long run. The system with a high amount of organic matter increases the production efficiency of applied inputs and also plays an important role in substituting chemical fertilizers. Alternative tillage management systems were evaluated for their sustainability using total factor productivity. It was found that conservation tillage meets criteria of sustainability more often than the management system containing conventional tillage. Conservation tillage was found to be the best alternative not only to sequester carbon but also developing natural capital-based sustainable system.
Classification of the solutions of constant rational semi-dynamical reflection equations
Creators: name: Avan, Jean
name: Rollet, Genevieve
Publisher: name: arXiv
Year: 2005
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Algebra (math.QA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We propose a classification of the solutions K to the semi-dynamical reflection equation with constant rational structure matrices associated to rational scalar Ruijsenaars-Schneider model. Four sets of solutions are identified and simple analytic transformations generate all solutions from these sets.
description: 12 pages, no figure. Dedicated to Daniel Arnaudon
Size-fractionated chlorophyll and primary productivity and nutrient distributions off the west coast of Vancouver Island
Creators: name: Harris, Shannon Lee
Publisher: name: University of British Columbia
Year: 2009

description: Spatial and temporal variability of nutrients, chlorophyll and primary productivity off the west coast of Vancouver Island are not well studied. This study examined how dissolved nutrients and size-fractionated biomass and primary productivity vary in time and space and evaluated the relative contribution of >5 μm size fraction of phytoplankton to total biomass and primary productivity. Size-fractionated primary productivity, and physical, chemical, and biological characteristics were studied during spring, summer and fall cruises for 1997 and 1998. Studies were conducted at four transects extending across the continental shelf, perpendicular to the west coast of Vancouver Island. Transects were over the La Perouse Bank, over Barkley Canyon, off Estevan Point and off Brooks Peninsula. Physical, chemical and biological characteristics of shelf regions were distinct from beyond shelf regions and showed a strong cross-shelf gradient. The shelf region was characterized by lower temperature and lower salinity. In addition, higher nitrate and silicic acid, and higher chlorophyll and primary productivity were observed in the shelf region compared to the beyond shelf region. Variability was very high off the west coast of Vancouver Island; often the mean and the standard deviation were similar. This study was conducted during a strong El Nino (1997/98) and La Nina (1998) event and interannual variation was evident. The mixed layer depth was shallower, nitrate, silicic acid and primary productivity were higher during El Nino. In contrast, phytoplankton biomass, diatom abundance and the relative contribution of >5 μm sized phytoplankton were higher during La Nifia. The >5 μm sized phytoplankton were dominated by the diatoms Chaetoceros spp. and Leptocylindrus danicus and contributed substantially to the biomass (62%) and primary productivity (57%) off the west coast of Vancouver Island. The relative contribution was higher in shelf regions than in beyond shelf regions. This study clearly showed that the contribution of the >5 μm size fraction was greatest at high biomass concentrations and high productivity rates supporting the idea that in order to reach high biomass and productivity, large cells are required.
Electric-field-dependent spectroscopy of charge motion using a single-electron transistor
Creators: name: Brown, K. R.
name: Sun, L.
name: Kane, B. E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present observations of background charge fluctuators near an Al-AlO_x-Al single-electron transistor on an oxidized Si substrate. The transistor design incorporates a heavily doped substrate and top gate, which allow for independent control of the substrate and transistor island potentials. Through controlled charging of the Si/SiO_2 interface we show that the fluctuators cannot reside in the Si layer or in the tunnel barriers. Combined with the large measured signal amplitude, this implies that the defects must be located very near the oxide surface.
description: 4 pages, 4 figures; typos corrected, minor clarifications added; published in APL
ECONOMICS OF POULTRY LITTER UTILIZATION AND OPTIMAL ENVIRONMENTAL POLICY FOR PHOSPHORUS DISPOSAL IN GEORGIA
Creators: name: Paudel, Krishna P.
name: McIntosh, Christopher S.
name: Paudel, Krishna P.
name: McIntosh, Christopher S.
Publisher: name: Unknown
Year: 2000
Subjects: Environmental Economics and Policy
Resource /Energy Economics and Policy

description: Poultry litter can be used as plant nutrients or cattle feed. Both of these alternatives may increase phosphorus concentration in the nearby watershed. Use of phosphorus consistent litter application rule in nutrient management combined with permit system has potential to curtail the over production of litter and prevent the possible contamination of water.
A simple parameterization of the consequences of deleptonization for simulations of stellar core collapse
Creators: name: Liebendoerfer, M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A simple and computationally efficient parameterization of the deleptonization, the entropy changes, and the neutrino stress is presented for numerical simulations of stellar core collapse. The parameterization of the neutrino physics is based on a bounce profile of the electron fraction as it results from state-of-the-art collapse simulations with multi-group Boltzmann neutrino transport in spherical symmetry. Two additional parameters include an average neutrino escape energy and a neutrino trapping density. The parameterized simulations reproduce the consequences of the delicate neutrino thermalization/diffusion process during the collapse phase and provide a by far more realistic alternative to the adiabatic approximation, which has often been used in the investigation of the emission of gravitational waves, of multi-dimensional general relativistic effects, of the evolution of magnetic fields, or even of the nucleosynthesis in simulations of core collapse and bounce. For supernova codes that are specifically designed for the postbounce phase, the parameterization builds a convenient bridge between the point where the applicability of a stellar evolution code ends and the point where the postbounce evolution begins.
description: 10 pages, 6 figures, revised version, to appear in ApJ
Decolonizing the Tropics: Part One
Creators: name: Lundberg, A
name: Chao, S
name: Ferrão, RB
name: Sinamai, Ashton
name: Okpadah, SO
name: Regis, H
name: Chwala, GL
Publisher: name: La Trobe
Year: 2024
Subjects: classificationCode: 4702
subject: Cultural studies
classificationCode: 4705
subject: Literary studies
classificationCode: 4410
subject: Sociology
subject: FOS: Sociology

description: This special issue is a collection of papers that addresses and enacts the theme of decolonizing the tropics. Each article provides a sense of how we can untangle ourselves from entrenched colonial epistemologies and ontologies through detailed articulations of research practice. Drawing together humanities and social sciences, the papers collectively address questions of whose voices are heard or silenced, what positions we write from, how we are allowed to articulate our ideas, and through which mediums we present our research. In doing so, the contributions foreground the critical importance of these and other questions in any move towards decolonizing the tropics.
Driving frequency effect on discharge parameters and higher harmonic generation in capacitive discharges at constant power densities
Creators: name: Sharma, Sarveshwar
name: Sirse, Nishant
name: Kuley, Animesh
name: Sen, Abhijit
name: Turner, Miles M
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Very high frequency (VHF) driven capacitive discharges are now being increasingly adopted for plasma-based materials processing due to their high processing rates and lower substrate damage. Past studies related to complex plasma dynamics and higher harmonics generation in such systems were limited to constant voltage/current conditions, whereas, industrial systems are mostly driven by constant power density sources. In the present study, using particle-in-cell (PIC) simulation, we explore the dynamics of collisionless symmetric capacitive discharges that is operated at constant power densities. Our focus is on the effect of the driving frequency on the discharge parameters like the electron density/temperature, the electron energy distribution function (EEDF), the ion energy distribution function (IEDF), and the generation of higher harmonics in the device. The simulations are performed for a driving frequency from 27.12-100 MHz in argon plasma at a gas pressure of 1 Pa and for two values of the power density, namely, 2 kW/m3 and 20 kW/m3. It is observed that the required discharge voltage for maintaining constant power density decreases and discharge current increases with an increase in the driving frequency. A transition frequency is observed at both power densities. The density decreases (electron temperature increases) before the transition frequency and the trend is reversed after crossing the transition frequency. The EEDF shows an enhancement in the population of the mid-energy range of electrons as the driving frequency increases up to the transition frequency thereby changing the shape of EEDF from bi-Maxwellian to nearly Maxwellian, and then transforms into a nearly bi-Maxwellian at higher driving frequencies.
Heating-compensated constant-temperature tunneling measurements on stacks of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ intrinsic junctions
Creators: name: Bae, Myung-Ho
name: Choi, Jae-Hyun
name: Lee, Hu-Jong
Publisher: name: arXiv
Year: 2005
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In highly anisotropic layered cuprates such as Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ tunneling measurements on a stack of intrinsic junctions in a high-bias range are often susceptible to self-heating. In this study we monitored the temperature variation of a stack ("sample stack") of intrinsic junctions by measuring the resistance change of a nearby stack ("thermometer stack") of intrinsic junctions, which was strongly thermal-coupled to the sample stack through a common Au electrode. We then adopted a proportional-integral-derivative scheme incorporated with a substrate-holder heater to compensate the temperature variation. This in-situ temperature monitoring and controlling technique allows one to get rid of spurious tunneling effects arising from the self-heating in a high bias range.
description: 3 pages, 3 figures
Does Scale Matter? Cost Effectiveness of Agricultural Nutrient Abatement When Target Level Varies
Creators: name: Iho, Antti
name: Iho, Antti
Publisher: name: Unknown
Year: 2005
Subjects: subject: Crop Production/Industries
subject: Resource /Energy Economics and Policy
subject: cost-effectiveness
subject: phosphorus abatement
subject: buffer strips
subject: wetlands
subject: fertilizer use
subject: water framework directive

description: Agricultural production is facing high requirements on nutrient runoff reduction. Furthermore, the reductions should by done efficiently. For instance, the European Water Framework Directive calls for cost-effectiveness from schemes of measures to fulfill the target of good water quality in European river basins. In this paper we analyse the implications of target level variation on efficiency properties of agricultural phosphorus abatement. We analyse the robustness of cost-effectiveness as the scheme of measures is adopted from another, identical river basin with different target level on total phosphorus abatement. We find that even between homogeneous regions the cost-effective scheme of measures is unique for all target levels of reduction, and that the costs of adoting cost-effective allocations out of scale are high.
Supporting Quality In Test Code For Higher Quality Software Systems
Creators: name: Spadini, Davide
Publisher: name: Zenodo
Year: 2021

description: Automated testing has become an essential process for improving the quality of software systems. Automated tests can help ensure that production code is robust under many usage conditions and that code meets performance and security needs. Nevertheless, writing effective tests is challenging and, unfortunately, often neglected. In the first part of this dissertation, we summarize and explain why test and production code are not treated with the same care, and we set our goal: we want to discover new techniques and tools to support developers when writing and reviewing test code. To this aim, we investigate the impact of test design issues on code quality and the practices when writing and reviewing test code. First, we create and make publicly available Pydriller, a Python framework to analyze software repositories that will help us gather important information for the following studies. Then, we study test design issues and their impact on the overall software code quality, demonstrating how important it is to have a good and effective test suite. Afterward, together with SIG, a company setting in which part of this dissertation was conducted, we study how developers in industry react to these test design issues. Our results show that the current detection rules for test issues are not precise enough and, more importantly, do not support prioritization. We present new rules that can be used to prioritize these issues and show that the results achieved with the new rules better align with developers' perception of importance. In the second part of the dissertation we focus on how to help developers better reviewing test code. First, we investigate developers' needs when it comes to code reviewing, identifying seven high-level information needs that could be addressed through automated tools, saving up time for reviewers. Then, we focus on code review of test code specifically: we first study when and how developers review test code, identifying current practices, revealing the challenges faced during test code reviews, and uncovering needs for tools that can support the review of test code. Later, we investigate the impact of Test-Driven Code Review (TDR) on the code review effectiveness, showing that it can increase the number of test code issues found. We discuss when TDR can and can not be applied and why not all developers see TDR as a worthy practice.
Resummation of event-shapes at hadron-hadron colliders
Creators: name: Zanderighi, G.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We point out that a study of event shapes at hadron colliders allows to explore novel aspects of QCD. These studies are today made easier by the development of a program which automates the resummation.
description: Invited talk at 2005 International Linear Collider Physics and Detector Workshop and Second ILC Accelerator Workshop, Snowmass, CO (Snowmass05), 3 pages
Intergalactic HeII absorption towards QSO 1157+3143
Creators: name: Reimers, D.
name: Fechner, C.
name: Hagen, H. -J.
name: Jakobsen, P.
name: Tytler, D.
name: Kirkman, D.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection toward QSO 1157+3143 (z ~ 3, B ~ 17). A 10 orbit follow-up spectrum reveals a UV spectrum significantly supressed by two intervening Lyman limit systems at z=2.77 and 2.94, but with the continuum flux recovering sufficiently shortward of ~ 1700 A to allow study of the HeII absorption spectrum in the redshift range 2.75 < z < 2.97. The absorption is characterized by alternating voids and dense filament structures seen in both HeII and HI. Attempts to model the HeII opacity in terms of HI Ly alpha forest absorption are not successful in the voids, suggesting that HeII reionization is not complete between z=2.77 and 2.97 or that an optically thin Lyman limit system with z ~ 0.3 is responsible for the additional opacity.
description: 6 pages, 4 figures, accepted by A&A
The Present Value Model, Farmland Prices and Structural Breaks
Creators: name: Gutierrez, Luciano
name: Erickson, Kenneth W.
name: Westerlund, Joakim
name: Gutierrez, Luciano
name: Erickson, Kenneth W.
name: Westerlund, Joakim
Publisher: name: Unknown
Year: 2005
Subjects: subject: Land Economics/Use
subject: farmland prices
subject: present value model
subject: non-stationary panel data analysis
subject: regime shift
subject: Q24

description: We review the constant discount rate present value model of farmland prices using non-stationary panel data analysis. We use panel unit root and cointegration analysis to test if the present value model holds for a sample of 31 U.S. States covering the period 1960-2000. Preliminary results indicate that farmland prices and cash rents are non-stationary and non-cointegrated assuming a constant discount rate. The absence of cointegration may be due to the presence of a regime shift representing a time-varying discount rate. To accommodate this possibility, we introduce new panel cointegration tests that allow for unknown regime shifts in the cointegration relationship. The results suggest that the cointegration hypothesis cannot be rejected if there is a regime shift. Thus, while the present value model of farmland prices must be rejected when the discount rate is presumed constant, it cannot be rejected once we allow for regime shifts representing a time-varying discount rate.
The association between adverse events across the lifespan and later-life health outcomes
Creators: name: NILAWEERA, DINULI PRATHIBHA
Publisher: name: Monash University
Year: 2024
Subjects: classificationCode: 320221
subject: Psychiatry (incl. psychotherapy)
classificationCode: 420699
subject: Public health not elsewhere classified

description: This thesis examines the extent to which stressful events experienced across the lifespan influences health outcomes in older individuals. It identifies that to varying degrees, stressful life events (including spousal death) are associated with an increased risk of mortality, poor cognition, and dementia in later life. Some events, such as lifetime trauma without symptoms of posttraumatic stress disorder, may also exert a protective effect. Gender may be an important factor in determining the extent to which adversity impacts later-life health. These findings are important in informing public health initiatives, particularly the screening of at-risk populations, such as bereaved men.
Alternate Heegaard genus bounds distance
Creators: name: Scharlemann, Martin
name: Tomova, Maggy
Publisher: name: arXiv
Year: 2005
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57N10, 57M50

description: Suppose M is a compact orientable irreducible 3-manifold with Heegaard splitting surfaces P and Q. Then either Q is isotopic to a possibly stabilized copy of P or the Hempel distance of the splitting P is no greater than twice the genus of Q. More generally, if P and Q are bicompressible but weakly incompressible connected closed separating surfaces in M then either a) P and Q can be well-separated or b) P and Q are isotopic or c) the Hempel distance of P is no greater than twice the genus of Q.
description: This is the version published by Geometry & Topology on 4 May 2006 (V4: typesetting correction)
DESENVOLVIMENTO DE SOFTWARE DE SUGESTÃO NA AGRICULTURA FAMILIAR EM PERNAMBUCO
Creators: name: ANDRADE, E. E. S
name: NASCIMENTO, F. J. M.
Publisher: name: Zenodo
Year: 2024
Subjects: SOFTWARE
AGRICULTURA
PERNAMBUCO

description: O resumo simplificado, intitulado "Desenvolvimento de Software de Sugestão na Agricultura Familiar em Pernambuco", foi submetido ao III Congresso Brasileiro Online de Ensino, Pesquisa e Extensão em 2024, organizado pela Sociedade Brasileira de Eventos Científicos (SOBREC). O autor principal, Everson Eduardo da Silva Andrade, cuja referência de citação é "Andrade, E. E. S.", apresentou o trabalho com o objetivo de divulgar conhecimento e incentivar o pensamento científico sobre o Desenvolvimento de Software de Sugestão na Agricultura Familiar em Pernambuco. O co-autor, Fernando Jeferson de Macedo Nascimento, contribuiu para a pesquisa, sendo sua referência de citação "Nascimento, F. J. M.". O evento busca conectar a divulgação científica, o ensino e a extensão acadêmica, visando atingir um amplo público interessado nessa temática.
Can Rank-Order Tournaments Improve Efficiency of Quality Differentiated Crop Markets Under Marketing Loan Program Operation? The Case of U.S. Peanuts.
Creators: name: Nadolnyak, Denis A.
name: Fletcher, Stanley M.
name: Revoredo-Giha, Cesar
name: Nadolnyak, Denis A.
name: Fletcher, Stanley M.
name: Revoredo-Giha, Cesar
Publisher: name: Unknown
Year: 2005
Subjects: subject: Marketing
subject: FOS: Economics and business
subject: contracts
subject: tournaments
subject: efficiency
subject: spot markets
subject: peanuts

description: In the paper, alternative contractual arrangements between crop producers and processors are evaluated with a view of addressing the major issues present in peanut markets in the U.S., the major EU supplier of high quality peanuts. The issues are the thinness of the spot markets and the absence of quality premiums, both of which impair market efficiency. Results indicate that introducing contracts with a system of quality differentials creates incentives for producer self-selection to participate in the post harvest cash market. Moreover, in the presence of sufficiently high common production risk, tournament contracts are more efficient and preferred by the producers than the standard fixed premium schedules.
Single- versus two-parameter Fisher information in quantum interferometry
Creators: name: Ataman, Stefan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper we reconsider the single parameter quantum Fisher information (QFI) and compare it with the two-parameter one. We find simple relations connecting the single parameter QFI (both in the asymmetric and symmetric phase shift cases) to the two parameter Fisher matrix coefficients. Following some clarifications about the role of an external phase [Phys. Rev. A 85, 011801(R) (2012)], the single-parameter QFI and its over-optimistic predictions have been disregarded in the literature. We show in this paper that both the single- and two-parameter QFI have physical meaning and their predicted quantum Cramér-Rao bounds are often attainable with the appropriate experimental setup. Moreover, we give practical situations of interest in quantum metrology, where the phase sensitivities of a number of input states approach the quantum Cramér-Rao bound induced by the single-parameter QFI, outperforming the two-parameter QFI.
description: 19 pages, 14 figures
Assessing the Effects of NAFTA ON Canada/US Agricultural Trade
Creators: name: Deng, Hugh
name: Nzuma, Jonathan M.
name: Deng, Hugh
name: Nzuma, Jonathan M.
Publisher: name: Unknown
Year: 2005
Subjects: subject: International Relations/Trade
subject: CUSTA/NAFTA
subject: agricultural trade
subject: liberalization
subject: integration
subject: trade flows

description: While there seems to be an agreement that Canada-US Free Trade Agreement (CUSTA)/North American Free Trade Agreement (NAFTA) have benefited member countries, some analysts have argued that the agreements had little effect on the bilateral Canada/US agricultural trade as many other factors have contributed to the increased trade flows. Results from this study reveal that the aggregate bilateral agricultural trade flows have generally experienced a steady growth since the implementation of NAFTA with trade flows seemingly favoring Canada more than the US since 1992. At the industry level, the impacts of NAFTA on Canada/US agricultural trade were varied with the sub-sectors analyzed responding differently to the bilateral trade liberalization.
Income Situation of Agricultural Households in Slovenia after EU Accession: Impacts of Different Direct Payments Policy Options
Creators: name: Kozar, Maja
name: Kavcic, Stane
name: Erjavec, Emil
name: Kozar, Maja
name: Kavcic, Stane
name: Erjavec, Emil
Publisher: name: Unknown
Year: 2005
Subjects: subject: Farm Management
subject: EU enlargement
subject: CAP reform
subject: total income
subject: income impacts
subject: Slovenia

description: Paper investigates income effects of different direct payments policy options after the accession of Slovenia to the EU by application of a static deterministic total income model for rural households in Slovenia (TIM). Model is based on actual income data of 120 agricultural households in Slovenia. With respect to pre-accession baseline situation and accession agreement, income situation of analyzed households is likely to improve under all analyzed policy scenarios. Estimated benefits are highest in case of standard direct payments scheme, followed by basic flat-rate area payment option (entirely decoupled). Model results reveal also that policy reform will have redistributive impacts in favour of agricultural households engaged in extensive agricultural production.
The Swedish 1990 Agricultural Reform - Adjustments of the Use of Land
Creators: name: Andersson, Fredrik Ca
name: Andersson, Fredrik Ca
Publisher: name: Unknown
Year: 2005
Subjects: subject: Agricultural and Food Policy
subject: sample selection
subject: agricultural reform
subject: Sweden
subject: set aside
subject: MTR

description: This paper provides an empirical analysis of adjustments of land use as a result of the conversion programme in the Swedish agricultural reform of 1990. The determinants of farmers' choice to voluntarily convert arable land to other uses and the share of land converted are analysed with the Heckman selection model. The results suggest that the decision to convert is significantly affected by a farmer's age, the size and location of the farm, the type of farming, and the macroeconomic situation in the region. Farm operators on farms highly specialised in grazing livestock and farmers on large farms were found to be more prone to convert.
Optimal finite-time bit erasure under full control
Creators: name: Proesmans, Karel
name: Ehrich, Jannik
name: Bechhoefer, John
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the finite-time erasure of a one-bit memory consisting of a one-dimensional double-well potential, with each well encoding a memory macrostate. We focus on setups that provide full control over the form of the potential-energy landscape and derive protocols that minimize the average work needed to erase the bit over a fixed amount of time. We allow for cases where only some of the information encoded in the bit is erased. For systems required to end up in a local equilibrium state, we calculate the minimum amount of work needed to erase a bit explicitly, in terms of the equilibrium Boltzmann distribution corresponding to the system's initial potential. The minimum work is inversely proportional to the duration of the protocol. The erasure cost may be further reduced by relaxing the requirement for a local-equilibrium final state and allowing for any final distribution compatible with constraints on the probability to be in each memory macrostate. We also derive upper and lower bounds on the erasure cost.
An Alkali-Vapor Cell with Metal Coated Windows for Efficient Application of an Electric Field
Creators: name: Sarkisyan, David
name: Sarkisyan, A. S.
name: Guéna, Jocelyne
name: Lintz, Michel
name: Bouchiat, Marie-Anne
Publisher: name: arXiv
Year: 2005
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We describe the implementation of a cylindrical T-shaped alkali-vapor cell for laser spectroscopy in the presence of a longitudinal electric field. The two windows are used as two electrodes of the high-voltage assembly, which is made possible by a metallic coating which entirely covers the inner and outer sides of the windows except for a central area to let the laser beams in and out of the cell. This allows very efficient application of the electric field, up to 2 kV/cm in a rather dense superheated vapor, even when significant photoemission takes place at the windows during pulsed laser irradiation. The body of the cell is made of sapphire or alumina ceramic to prevent large currents resulting from surface conduction observed in cesiated glass cells. The technique used to attach the monocrystalline sapphire windows to the cell body causes minimal stress birefringence in the windows. In addition, reflection losses at the windows can be made very small. The vapor cell operates with no buffer gas and has no magnetic part. The use of this kind of cell has resulted in an improvement of the signal-to-noise ratio in the measurement of Parity Violation in cesium vapor underway at ENS, Paris. The technique can be applied to other situations where a brazed assembly would give rise to unacceptably large birefringence in the windows.
Reforms and Efficiency Change in Transition Agriculture
Creators: name: Swinnen, Johan F.M.
name: Vranken, Liesbet
name: Swinnen, Johan F.M.
name: Vranken, Liesbet
Publisher: name: Unknown
Year: 2005
Subjects: subject: Agribusiness
subject: transition
subject: production efficiency
subject: reforms

description: Studies on efficiency changes in transition agriculture yield mixed results. This paper develops both a theoretical model and an empirical analysis of how distribution of efficiency scores changes with the various stages of transition. We use a unique set of representative farm survey data to calculate farm level efficiency scores, compare the efficiency distributions of different transition countries and correlate these with various indicators of particular reforms. Our study indicates that, in particular, general institutional reforms and reforms focused on market institutions and on reducing market imperfections in input and output markets have an important positive impact on farm efficiency.
Water Saving Technology in Chinese Rice Production - Evidence from Survey Data
Creators: name: Abdulai, Awudu
name: Glauben, Thomas
name: Herzfeld, Thomas
name: Zhou, Shudong
name: Abdulai, Awudu
name: Glauben, Thomas
name: Herzfeld, Thomas
name: Zhou, Shudong
Publisher: name: Unknown
Year: 2005
Subjects: subject: Crop Production/Industries
subject: China
subject: technology adoption
subject: water
subject: GCRPS
subject: probit

description: Whereas water is an important input in rice production, China faces severe problems with increasing demand for water and limited water resources. In conventional paddy production, one of the most important irrigated crops, a significant amount of irrigation water is lost due to percolation and evaporation. Therefore, it exist a vivid research in water saving rice technologies. This paper analyzes the adoption of one of these water-saving rice production technologies, the so-called Ground Cover Rice Production System (GCRPS), in the Hubei province. Based on farm survey data several factors which affect the adoption decision could be identified. The adoption decision is treated as a binary choice problem and therefore a probit model is used for the econometric analysis. The main determinants of the adoption decision are the number of previous adoptions, the membership in an extension service and the income of the household. Additionally, soil characteristics show a significant impact on the probability of adoption.
Using otoliths to determine daily growth rate and size-selective mortality of juvenile salmon in Nanaimo, British Columbia
Creators: name: Nayar, Tarun Adrian
Publisher: name: University of British Columbia
Year: 2009

description: Available evidence suggests that interannual variability in the recruitment of Pacific salmon is related to survival in the first few months juveniles spend at sea. Differential growth of smolts during this stage is often thought to result in interannual differences in marine survival, as those fish that grow faster may be less vulnerable to predators or physiological and environmental stressors associated with overwintering (i.e. the 'differential growth' hypothesis). Due to the limitations of traditional techniques, however, only rarely has salmon growth been reliably characterized during the early marine stage. Using juvenile chum salmon (Oncorhynchus keta) collected in the Nanaimo area (1999-2001), I demonstrate that otoliths provide a powerful means of examining the early life history of individual salmon in the field. I used a fluorescent marker to validate the daily periodicity of otolith increment formation, and the formation of a marine entry check. I then back-calculated size-atmarine- entry for each chum smolt to provide individual estimates of early marine growth rate from the summers of 1999 and 2000. Mean daily growth rates were significantly higher, and size-at-entry significantly larger, in 1999 (0.084 cm day"1, 4.48 cm) than in 2000 (0.076 cm day"1, 3.97 cm). 1999 was also a year of significantly higher gut fullness and lower sea surface temperatures. By comparing growth rate frequencies across trips, I found evidence for size-selective mortality of slow growing fish in the midsummer of 2000. These patterns are consistent with the "differential growth hypothesis". In years of unfavourable ocean conditions, juvenile salmon may experience slower growth and higher rates of size-selective predation (possibly due to low food availability or quality). This, in turn, may lead to below average survival and recruitment in these years.