4,069 research outputs found
Warming and Ocean Acidification Effects in the Seaweed Community of West Spitsbergen
Global change-related warming and ocean acidification (OA) are major threats to the Svalbard coastal ecosystem. Rock bottom areas are mainly dominated by dense forests of a multi-species community of seaweeds. Different species are shown to respond to warming and OA in different ways and degrees, posing a potential shift in community structure as the new scenario develops. An increase in CO2 is shown to modify the carbon balance of two representative species in opposing ways. Growth rate of Desmarestia aculeata was negatively affected by CO2 enrichment, while Alaria esculenta was positively affected, as a result of a different reorganization of the cellular carbon budget in both species. D. aculeata showed increased respiration, enhanced accumulation of storage biomolecules and elevated release of dissolved organic carbon, whereas A. esculenta showed decreased respiration and lower accumulation of storage biomolecules. Moreover, incubation of 6 species from Kongsfjorden at different CO2 and temperature levels indicated that temperature affected mainly the photosynthetic performance as measured by PAM fluorescence, particularly the initial slope of ETR curves, the light saturation parameter (Ek), and Fv/Fm values, as well as the protein content, especially in the phaeophytes. On the other hand, CO2 affected mainly the internal accumulation of carbohydrates and lipids. The C:N balance was largely unaffected. The resulting growth rate was not altered by the treatments in three out of the six species studied. For example, Phycodris rubens showed a positive effect of increasing temperature, while Saccorhiza dermatodea was positively affected by CO2. Significant interactions between CO2 and temperature were found in 20 % of the analyses. Whether additive or synergistic, the co-occurrence of a higher temperature with other stressors such as elevated CO2 increases the probability of community changes by modifying the performance of these species. To test whether this kind of responses was characteristic of Arctic populations, Saccharina latissima from Kongsfjorden was compared to the population from Helgoland (Germany). Ecotypic variations were revealed by a significantly higher O2 production rate and an increase in Chl a, Rubisco, and D1 protein content in the Arctic population thalli, but a lower growth rate, in comparison to the Atlantic population. At 10 °C, the Arctic population had a higher content of total C, soluble carbohydrates, and lipids, whereas the N- and protein content was lower. Conclusively, the Arctic ecotype was more resilient to increased CO2 than the temperate one, and both ecotypes differed in their response pattern to temperature. Overall, Arctic ecotypes of seaweeds have shown an array of responses pointing to an altered community as the “atlantification” and acidification of the West Spitsbergen coastal system take place. Further research will focus on potential alteration of the nutrient regime due to increased discharge from land and its consequences on seaweeds metabolic performance.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Neutrino footprint in Large Scale Structure
Recent constrains on the sum of neutrino masses inferred by analyzing
cosmological data, show that detecting a non-zero neutrino mass is within reach
of forthcoming cosmological surveys, implying a direct determination of the
absolute neutrino mass scale. The measurement relies on constraining the shape
of the matter power spectrum below the neutrino free streaming scale: massive
neutrinos erase power at these scales. Detection of a lack of small-scale
power, however, could also be due to a host of other effects. It is therefore
of paramount importance to validate neutrinos as the source of power
suppression at small scales. We show that, independent on hierarchy, neutrinos
always show a footprint on large, linear scales; the exact location and
properties can be related to the measured power suppression (an astrophysical
measurement) and atmospheric neutrinos mass splitting (a neutrino oscillation
experiment measurement). This feature can not be easily mimicked by systematic
uncertainties or modifications in the cosmological model. The measurement of
such a feature, up to 1% relative change in the power spectrum, is a smoking
gun for confirming the determination of the absolute neutrino mass scale from
cosmological observations. It also demonstrates the synergy of astrophysics and
particle physics experiments.Comment: arXiv admin note: text overlap with arXiv:1003.591
Some Observations and One Building
The last three decades have witnessed architecture\u27s frequent fluctuations from one design impulse to another. Contextualism, postmodernism, deconstructivism, virtualism and bigness are but a few
Determinants of Meats Purchase Behavior by Ethnic Groups
Farmers and food companies need to assess their production and marketing strategies for nurturing business opportunities that will arise from the simultaneous increase in population and income of Hispanics in the United States. Previous studies on demand for meat products have not received much attention on the determinants of meats purchase behavior by Hispanics in relation to other ethnic groups. This study investigates the impact of ethnicity and the determinants of meats purchase behavior in the U.S. by using single Probit equations. The analyzed data comes from the U.S. Consumer Expenditure Survey. The results indicate that ethnicity plays an important role in the purchase behavior of meat products, as well as household size and income.consumer behavior, marketing, food demand, Hispanic food, hispanic food market, Latin foods, comida latina, alimentos, ethnic foods, Agribusiness, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Industrial Organization, Marketing, D01, D03, D12, L14, L66, M31, M37,
The Effects of Public Debt on Labor Demand in the United States
The relationship between appreciation of the exchange rate and employment is investigated in the period 1980-2008 for the United States. Previous literature has found a negative relationship, studying as channels of transmission the role of exports, substitution of factors of production, terms of trade, openness, and productivity. This study endeavors to shed some light on the role of government debt on determining the level of employment through the exchange rate. The mechanism of transmission is defined. The model is derived from a standard Cobb Douglas production function having government debt affecting the growth of productivity. Exchange rate appreciations and increasing public debt were found to be detrimental to employment.Unemployment rate, government, budget deficit, exchange rate, trade deficit, FDI, Financial Economics, International Development, Labor and Human Capital, Political Economy, Public Economics, F31, J01, E24, E62,
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