11,420 research outputs found
Effect of Waste Discharges into a Silt-laden Estuary: A Case Study of Cook Inlet, Alaska
Cook Inlet is not well known. Although its thirty-foot tidal range is widely appreciated,
its other characteristics, such as turbulence, horizontal velocities of flow, suspended sediment
loads, natural biological productivity, the effects of fresh water inflows, temperature,
and wind stresses, are seldom acknowledged. The fact that the Inlet has not been used for
recreation nor for significant commercial activity explains why the average person is not
more aware of these characteristics. Because of the gray cast created by the suspended
sediments in the summer and the ice floes in the winter, the Inlet does not have the aura of
a beautiful bay or fjord. The shoreline is inhospitable for parks and development, the currents
too strong for recreational activities, and, because of the high silt concentration, there
is little fishing. Yet, Cook Inlet, for all its negative attributes, can in no way be considered
an unlimited dumping ground for the wastes of man. It may be better suited for this purpose
than many bays in North America, but it does have a finite capacity for receiving
wastes without unduly disturbing natural conditions.
This report was written for the interested layman by engineers and scientists who tried
to present some highly technical information in such a manner that it could be understood
by environmentalists, concerned citizens, students, decision makers, and lawmakers alike.
In attempting to address such a diverse audience, we risked failing to be completely understood
by any one group. However, all too often research results are written solely for other
researchers, a practice which leads to the advancement of knowledge but not necessarily to
its immediate use by practicing engineers nor to its inclusion in social, economic, and
political decision-making processes. We hope this report will shorten the usual time lag between
the acquisition of new information and its use. Several additional reports will be
available for a limited distribution. These will be directed to technicians who wish to know
the mathematical derivations, assumptions, and other scientific details used in the study.
Technical papers by the individual authors, published in national and international scientific
and engineering journals, are also anticipated.The work upon which this report is based was supported in part by funds (Proj. B-015-ALAS)
provided by the United States Department of the Interior, Office of Water Resources
Research, as authorized under the Water Resources Act of 1964, as amended
The Value of Health and Longevity
We develop an economic framework for valuing improvements to health and life expectancy, based on individuals' willingness to pay. We then apply the framework to past and prospective reductions in mortality risks, both overall and for specific life-threatening diseases. We calculate (i) the social values of increased longevity for men and women over the 20th century; (ii) the social value of progress against various diseases after 1970; and (iii) the social value of potential future progress against various major categories of disease. The historical gains from increased longevity have been enormous. Over the 20th century, cumulative gains in life expectancy were worth over 3.2 trillion per year to national wealth, an uncounted value equal to about half of average annual GDP over the period. Reduced mortality from heart disease alone has increased the value of life by about 500 billion.
Current Unemployment, Historically Contemplated
macroeconomics, Current Unemployment
Regularized parametric system identification: a decision-theoretic formulation
Parametric prediction error methods constitute a classical approach to the
identification of linear dynamic systems with excellent large-sample
properties. A more recent regularized approach, inspired by machine learning
and Bayesian methods, has also gained attention. Methods based on this approach
estimate the system impulse response with excellent small-sample properties. In
several applications, however, it is desirable to obtain a compact
representation of the system in the form of a parametric model. By viewing the
identification of such models as a decision, we develop a decision-theoretic
formulation of the parametric system identification problem that bridges the
gap between the classical and regularized approaches above. Using the
output-error model class as an illustration, we show that this
decision-theoretic approach leads to a regularized method that is robust to
small sample-sizes as well as overparameterization.Comment: 10 pages, 8 figure
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Characterizing the Dysfunctional NK Cell: Assessing the Clinical Relevance of Exhaustion, Anergy, and Senescence.
There is a growing body of literature demonstrating the importance of T cell exhaustion in regulating and shaping immune responses to pathogens and cancer. Simultaneously, the parallel development of therapeutic antibodies targeting inhibitory molecules associated with immune exhaustion (such as PD-1, but also TIGIT, and LAG-3) has led to a revolution in oncology with dramatic benefits in a growing list of solid and hematologic malignancies. Given this success in reinvigorating exhausted T cells and the related anti-tumor effects, there are increasing efforts to apply immune checkpoint blockade to other exhausted immune cells beyond T cells. One approach involves the reinvigoration of "exhausted" NK cells, a non-T, non-B lymphoid cell of the innate immune system. However, in contrast to the more well-defined and established molecular, genetic, and immunophenotypic characteristics of T cell exhaustion, a consensus on the defining functional and phenotypic features of NK "exhaustion" is less clear. As is well-known from T cell biology, separate and distinct molecular and cellular processes including senescence, anergy and exhaustion can lead to diminished immune effector function with different implications for immune regulation and recovery. For NK cells, it is unclear if exhaustion, anergy, and senescence entail separate and distinct entities of dysfunction, though all are typically characterized by decreased effector function or proliferation. In this review, we seek to define these distinct spheres of NK cell dysfunction, analyzing how they have been shown to impact NK biology and clinical applications, and ultimately highlight key characteristics in NK cell function, particularly in relation to the role of "exhaustion.
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