2,670 research outputs found
Does nitrate deposition following astrophysical ionizing radiation events pose an additional threat to amphibians?
It is known that amphibians are especially susceptible to the combination of
heightened UVB radiation and increased nitrate concentrations. Various
astrophysical events have been suggested as sources of ionizing radiation that
could pose a threat to life on Earth, through destruction of the ozone layer
and subsequent increase in UVB, followed by deposition of nitrate. In this
study, we investigate whether the nitrate deposition following an ionizing
event is sufficiently large to cause an additional stress beyond that of the
heightened UVB previously considered. We have converted predicted nitrate
depositions to concentration values, utilizing data from the New York State
Department of Environmental Conservation Acid Rain Monitoring Network web site.
Our results show that the increase in nitrate concentration in bodies of water
following the most intense ionization event likely in the last billion years
would not be sufficient to cause a serious additional stress on amphibian
populations and may actually provide some benefit by acting as fertilizer.Comment: This version is a longer, more detailed draft of an article submitted
to the journal Astrobiolog
Recognition of non-Milankovitch sea-level highstands at 185 and 343 thousand years ago from U-Th dating of Bahamas sediment
Thirty-one new bulk-sediment U-Th dates are presented, together with an improved δ18O stratigraphy, for ODP Site 1008A on the slopes of the Bahamas Banks. These ages supplement and extend those from previous studies and provide constraints on the timing of sea-level highstands associated with marine isotope stages (MIS) 7 and 9. Ages are screened for reliability based on their initial U and Th isotope ratios, and on the aragonite fraction of the sediment. Twelve 'reliable' dates for MIS 7 suggest that its start is concordant with that predicted if climate is forced by northern-hemisphere summer insolation following the theory of Milankovitch. But U-Th and δ18O data indicate the presence of an additional highstand which post-dates the expected end of MIS 7 by up to 10 ka. This event is also seen in coral reconstructions of sea-level. It suggests that sea-level is not responding in any simple way to northern-hemisphere summer insolation, and that tuned chronologies which make such an assumption are in error by ≈10 ka at this time. U-Th dates for MIS 9 also suggest a potential mismatch between the actual timing of sea-level and that predicted by simple mid-latitude northern-hemisphere forcing. Four dates are earlier than that predicted for the start of MIS 9. Although the most extreme of these dates may not be reliable (based on the low-aragonite content of the sediment) the other three appear robust and suggest that full MIS 9 interglacial conditions were established at 343 ka. This is ≈8 ka prior to the date expected if this warm period were driven by northern-hemisphere summer insolation. © 2006 Elsevier Ltd. All rights reserved
IMPLICIT ADDITIVE PREFERENCES: A FURTHER GENERALIZATION OF THE CES
The CES is generalized by extension of the work of Hanoch (1975) resulting in implicit, direct and indirect relationships between utility and consumption. Expressions for substitution and income elasticities are developed and observed to be variable, rather than constant as in the CES case.Food Consumption/Nutrition/Food Safety,
A Modified, Implicit, Directly Additive Demand System
A recently developed demand system, nicknamed AIDADS, offers a more general approach to capturing consumption preferences. AIDADS generalizes the LES by assuming marginal budget shares vary indirectly with expenditure. AIDADS is limited by the fact that the subsistence parameters are constant across expenditure. We modify AIDADS by replacing the constant subsistence parameters with a function which varies with utility, and hence expenditure. The modified AIDADS (MAIDADS) allows subsistence levels to vary with expenditure. This model is applied to the 1996 International Consumption Project data. As these data span a wide range of expenditure levels, MAIDADS offers a viable alternative when estimating "global demand systems." Results suggest subsistence values for livestock and other food products vary with expenditure, while those for grain are constant across expenditure.Demand and Price Analysis,
Marine snow derived from abandoned larvacean houses: Sinking rates, particle content and mechanisms of aggregate formation
Global Nutrition Impacts of Rapid Economic Growth in China and India
Despite record global economic growth in past decade malnutrition remains a serious problem in many parts of the world. According to the United Nations Food and Agriculture Organization (FAO), about 800 million people (17% of the worlds population) remain malnourished. For these households at a subsistence level of income, changes in commodity market conditions, as may arise from changes in global economic growth and/or trade policy can have serious consequences for nutritional intake. Even a small decline in diet quality can have substantial adverse impacts on health status. On the other hand, a modest income boost, or lower food prices, could have extremely positive impacts. Previously, the links between changes in the global economy and nutritional outcomes have been explored by a relatively wide range of authors (e.g., Fang et al., 2006; Rosegrant et al., 2005). The goal of this paper is to offer modest extensions of this previous work in three directions. First of all, unlike many of the papers in the nutrition area, we seek to account for the behavioral response of low income households in the face of changing prices and incomes. Clearly when households are faced with a rise in the price of food products, they cannot afford to consume as much, ceteris paribus so consumption much adjust. The extent of this adjustment will depend on the change in real income and the Engel elasticities for each good. In addition, consumers are likely to substitute away from higher cost food items. All of these factors could have an adverse impact on nutritional attainment. By estimating and incorporating a demand system into our analysis, we are able to take these factors into account. In so doing, we draw on the work of Rimmer and Powell (1996) and Cranfield et al. (2003a; 2003b) in order to characterize consumer demands across the income spectrum. A second important extension embodied in this work relates to the impact of changes in factor earnings on household nutritional attainment in the wake of globalization. Most economic analyses of this issue have tended to focus on the commodity price impacts of globalization. If they have taken into account the earnings-side impacts, they have typically done so in a simplistic way. In this paper, we seek to capture the earnings-heterogeneity of poor households and thereby shed light on the differential impact of global economic growth on different household groups. We do so using the framework developed in Hertel et al. (2004), and further refined in Hertel et al. (2007a). The final contribution of this paper is to imbed this framework for analysis of nutritional issues into a widely used, global general equilibrium model (GTAP: Hertel, 1997) in order to permit nutritional outcomes to be routinely reported as part of standard economic analyses of global economic growth and trade liberalization. We illustrate this approach to the analysis of nutritional impacts of global economic growth through a series of globalization shocks, focusing on the impacts in Bangldesh. We begin by considering solely the impact of an exogenous rise in the consumer price rise for food products. This permits us to illustrate the mechanisms through which low income consumers respond to changing economic conditions in our framework. We then turn to an analysis of the impact of economic growth in India and China, respectively, on the poor in Bangladesh, and in particular on their nutritional attainment. Our findings indicate that the nutritional impacts of globalization depend importantly on the source of the globalization shock, and the resultant earnings effects on the poor.Food Consumption/Nutrition/Food Safety,
Patient and Family Caregivers’ Experiences of Living With a Jejunostomy Feeding Tube After Surgery for Esophagogastric Cancer
BACKGROUND: Jejunostomy feeding tubes (JFTs) can be used to provide nutrition support to patients who have had surgery for esophagogastric cancer. Although previous research reports how patients cope with a gastrostomy tube, little is known about the impact of having a JFT. The aim of this qualitative study was to explore how patients and their informal caregivers experience living with a JFT in the first months following surgery. METHODS: Participants were purposively sampled from a cohort of patients recruited to a trial investigating home enteral nutrition vs standard care after esophagogastric surgery for cancer. The sampling framework considered age, sex, and marital status. Informal caregivers were also invited to participate. Interviews were audio recorded, transcribed verbatim, and anonymized. Inductive thematic analysis was used to identify key themes related to living with a JFT. RESULTS: Fifteen patient interviews were conducted; 8 also included a family caregiver. Analysis of the data resulted in 2 main themes: "challenges" and "facilitators" when living with a JFT. While "physical effects," "worries" and "impact on routine" were the main challenges, "support," "adaptation" and "perceived benefit" were what motivated continuation of the intervention. CONCLUSION: Findings suggest that participants coped well with a JFT, describing high levels of compliance with stoma care and the feeding regimen. Nonetheless, disturbed sleep patterns and stoma-related problems proved troublesome. A better understanding of these practical challenges, from the patient and family caregiver perspective, should guide healthcare teams in providing proactive support to avoid preventable problems
Glaciation on the Arctic Slope of the Brooks Range, Northern Alaska
Reconstructs glacial history of the area (approx. 68-69 30 N, 147-162 W) on the basis of observations during 1944-1953 of the nature and extent of glacial deposits in the central part of the Range between Shainin and Itkillik Lakes and in the southern part of the Foothills Province from the Shaviovik River west to Etivluk River. Distribution is mapped and characteristics described of deposits from six glaciations for which a tentative chronological sequence is established: Anaktuvuk and Sagavanirktok of Pre-Wisconsin age; Itkillik and Echooka of Early Wisonsin; Alapah Mountain of Late Wisconsin; and Fan Mountain of Recent age. Terrace deposits and Pleistone alluviations are mentioned
Pendugaan Fungsi Produksi Dan Fungsi Penawaran Genteng Beton Nuasntara Di PT. Varia Usaha Beton Sidoarjo
Persaingan di bidang perdagangan dan industri dewasa
ini dirasakan semakin tajam. Untuk itu perlu kiranya P.T.
VARIA USAHA BETON Sidoarjo meningkatkan produksinya baik
dari segi kualitas maupun kuantitas. Hal 1n1 bertujuan
untuk memenuhi kebutuhan konsumen yang semakin meningkat
sejalan dengan perubahan jaman. Dengan kualitas yang baik
dan harga yang memadai, maka omset penjualannya terus
mengalami kenaikan dari waktuu ke waktu.
Salah satu produksi di P.T. VARIA USAHA BETON Sidoarjo
adalah genteng beton nusantara yang relatif murah dan
terjangkau oleh daya beli masyarakat. Sehingga produksi
dan penawarannya akan mengalami peningkatan. Oleh sebab
itu penelitian ini menduga fungsi produksi dan fungsi penawaran
genteng beton jenis nusantara dengan melibatkan
faktor-faktor yang mempengaruhinya. Pada fungsi Produksi
digunakan model Cobb-Douglas, sedangkan fungsi penawaran
menggunakan model Linear. Sedangkan metode pendugaannnya
digunakan Metode Kuadrat Terkecil
Trees over Infinite Structures and Path Logics with Synchronization
We provide decidability and undecidability results on the model-checking
problem for infinite tree structures. These tree structures are built from
sequences of elements of infinite relational structures. More precisely, we
deal with the tree iteration of a relational structure M in the sense of
Shelah-Stupp. In contrast to classical results where model-checking is shown
decidable for MSO-logic, we show decidability of the tree model-checking
problem for logics that allow only path quantifiers and chain quantifiers
(where chains are subsets of paths), as they appear in branching time logics;
however, at the same time the tree is enriched by the equal-level relation
(which holds between vertices u, v if they are on the same tree level). We
separate cleanly the tree logic from the logic used for expressing properties
of the underlying structure M. We illustrate the scope of the decidability
results by showing that two slight extensions of the framework lead to
undecidability. In particular, this applies to the (stronger) tree iteration in
the sense of Muchnik-Walukiewicz.Comment: In Proceedings INFINITY 2011, arXiv:1111.267
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