491 research outputs found
The Trade Reducing Effects of Market Power in International Shipping
Developing countries pay substantially higher transportation costs than developed nations, which leads to less trade and perhaps lower incomes. This paper investigates price discrimination in the shipping industry and the role it plays in determining transportation costs. In the presence of market power, shipping prices depend on the demand characteristics of goods being traded. We show theoretically and estimate empirically that shipping firms charge higher prices when transporting goods with higher product prices, lower import demand elasticities, and higher tariffs, and when facing fewer competitors on a trade route. These characteristics explain more variation in shipping prices than do conventional proxies such as distance, and significantly contribute to the higher shipping prices facing the developing world. Markups increase shipping prices by at least 83 percent for the mean shipment in Latin American imports. Our findings are also important for evaluating the impact of tariff liberalization. Shipping firms decrease prices by 1-2 percent for every 1 percent reduction in tariffs.
Using jet mass to discover vector quarks at the LHC
We illustrate the utility of jet mass distributions as probes of new physics
at the LHC, focusing on a heavy vector-quark doublet that mixes with the top as
a concrete example. For 1 TeV vector-quark masses, we find that signals with
greater than 5 sigma significance can be achieved after 100 fb^-1. More
generally, jet mass distributions have the potential to provide signals for
heavy states that produce highly boosted weak gauge bosons and/or top quarks.Comment: 7pages, 5 figures; references adde
Greenhouse gas emissions, inventories and validation
The emission of greenhouse gases has become a very high priority research and environmental policy issue due to their effects on global climate. The knowledge of changes in global atmospheric concentrations of greenhouse gases since the industrial revolution is well documented, and the global budgets are reasonably well known. However, even at this scale there are important uncertainties in the budgets, for example, in the case of methane while the main sources and sinks have been identified, temporal changes in the global average concentrations since the early 1990s are not understood. In the absence of a quantitative explanation with appropriate experimental support, it is clear that current knowledge of the causes of changes in the global methane budget is inadequate to predict the effect of changes in specific emission sectors.
In developing control strategies to reduce emissions it is necessary to validate national emissions and their spatial disaggregation. The methodology to underpin such a process is at an early stage of development and is not fully implemented in any country, even though target emission reductions have already been announced. Furthermore, the scale of the emission reductions is large (eg of 60% reductions by 2050 relative to 1990 baseline). There is therefore an urgent requirement for measurement based verification processes to support such challenging emission reductions.
In this paper we provide the background in greenhouse gas emissions globally and in the UK followed by examples of approaches to validate emissions at the UK scale and within the regions
Supply and Demand Considerations for the U.S. Health Care Workforce: What May the Future Hold?
Five factors that influence supply and demand within the health care workforce are demographics, education, the healthcare delivery system, the economy, and context. These factors are interdependent and powerfully influence stakeholders involved in health care administration. All of them are in constant flux and heavily rely on the economy and context – two of the five factors that gained prominence since the Great Recession and determine strategy and policy related to future employment in all professional sectors. This paper reviews these factors from the vantage points of selected health care professions, and examines the opportunities and threats that lie ahead
Social Workers\u27 Perceptions of Family Preservation Programs
The passage of the Adoptions and Safe Families Act of 1997, with its focus on child safety and concurrent planning, has presented family preservation workers with new challenges and new opportunities. Twenty volunteers from a large comprehensive social service agency were interviewed to determine their experiences with two models of family preservation—Multisystemic Therapy (MST) and Traditional Family Preservation Service (TFPS) or practice as usual. Workers from both programs were able to articulate values consistent with family preservation as important strengths of the programs— keeping families together and empowering families for example. Information from referring agencies was described as variable and not especially useful when working with seriously troubled families, especially as it related to risk and child safety. Both groups indicated that the jargon of family preservation had permeated their agencies, and that working with other agencies was at times a challenge, though for different reasons. Finally, despite some reservations about the effectiveness of short-term treatment with families that face serious challenges, both groups of workers were generally satisfied with family preservation as an approach to practice
Giant Stark effect in the emission of single semiconductor quantum dots
We study the quantum-confined Stark effect in single InAs/GaAs quantum dots
embedded within a AlGaAs/GaAs/AlGaAs quantum well. By significantly increasing
the barrier height we can observe emission from a dot at electric fields of
-500 kV/cm, leading to Stark shifts of up to 25 meV. Our results suggest this
technique may enable future applications that require self-assembled dots with
transitions at the same energy
The role of infiltrating immune cells in dysfunctional adipose tissue
Adipose tissue (AT) dysfunction, characterized by loss of its homeostatic functions, is a hallmark of non-communicable diseases. It is characterized by chronic low-grade inflammation and is observed in obesity, metabolic disorders such as insulin resistance and diabetes. While classically it has been identified by increased cytokine or chemokine expression, such as increased MCP-1, RANTES, IL-6, interferon (IFN) gamma or TNFα, mechanistically, immune cell infiltration is a prominent feature of the dysfunctional AT. These immune cells include M1 and M2 macrophages, effector and memory T cells, IL-10 producing FoxP3+ T regulatory cells, natural killer and NKT cells and granulocytes. Immune composition varies, depending on the stage and the type of pathology. Infiltrating immune cells not only produce cytokines but also metalloproteinases, reactive oxygen species, and chemokines that participate in tissue remodelling, cell signalling, and regulation of immunity. The presence of inflammatory cells in AT affects adjacent tissues and organs. In blood vessels, perivascular AT inflammation leads to vascular remodelling, superoxide production, endothelial dysfunction with loss of nitric oxide (NO) bioavailability, contributing to vascular disease, atherosclerosis, and plaque instability. Dysfunctional AT also releases adipokines such as leptin, resistin, and visfatin that promote metabolic dysfunction, alter systemic homeostasis, sympathetic outflow, glucose handling, and insulin sensitivity. Anti-inflammatory and protective adiponectin is reduced. AT may also serve as an important reservoir and possible site of activation in autoimmune-mediated and inflammatory diseases. Thus, reciprocal regulation between immune cell infiltration and AT dysfunction is a promising future therapeutic target
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