4,519 research outputs found
The Next American Century: A Traditional Hard Power Problem or a New World Order?
There is a general consensus that the new world order gathered steam in response to World War II. Major institutions like the United Nations, NATO, and the Universal Declaration of Human Rights all fortified the common belief that economic, social, and political interdependence is unavoidable. This international framework in which both domestic and foreign policies have far-reaching and unclear implications is not well understood. Important debates concerning economic and military intervention in developing countries, the scope and enforceability of human rights, and the role of international governing bodies are far from settled. This raises an important question for the United States: What ought to be the values that define American foreign policy given these highly contentious circumstances? More specifically, should the United States rely primarily on its military strength as leverage? Can the U.S. maintain its superpower status? What might this look like in the future and is this desirable? These are the questions that will guide a discussion between Thomas Visco and Alex Zimmerman.\u
A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys
Due to inadequacies of previous underwater towing techniques and the special needs of a recent underwater survey, a modified mania-board technique was developed. With this new technique, the diver holds on to the manta-board with one arm; consequently, the board is referred to as a single-armed manta-board (sam-board). The sam-board proved inexpensive and highly maneuverable, allowing the divers to freely collect samples or record information. Through some experimenting with the board and changing some of the variables, such as rope lengths, towing speeds, etc., a highly efficient towing method can be achieved. Preplanning and strict diving safety procedures must, however, be implemented to assure efficiency. This paper presents the materials, guidelines for board construction, equipment, and preplanning and diving safety procedures necessary for the sam-board towing operation
Dynamics of Co-translational Membrane Protein Integration and Translocation via the Sec Translocon
An important aspect of cellular function is the correct targeting and delivery of newly synthesized proteins. Central to this task is the machinery of the Sec translocon, a transmembrane channel that is involved in both the translocation of nascent proteins across cell membranes and the integration of proteins into the membrane. Considerable experimental and computational effort has focused on the Sec translocon and its role in nascent protein biosynthesis, including the correct folding and expression of integral membrane proteins. However, the use of molecular simulation methods to explore Sec-facilitated protein biosynthesis is hindered by the large system sizes and long (i.e., minute) timescales involved. In this work, we describe the development and application of a coarse-grained simulation approach that addresses these challenges and allows for direct comparison with both in vivo and in vitro experiments. The method reproduces a wide range of experimental observations, providing new insights into the underlying molecular mechanisms, predictions for new experiments, and a strategy for the rational enhancement of membrane protein expression levels
Roe v. Wade and American Fertility
We consider the effect of abortion legalization on births in the United States. A simple theoretical model demonstrates that the impact of abortion legalization on the birth rate is ambiguous, because both pregnancy and abortion decisions could be affected. We use variation in the timing of legalization across states in the early 1970's to estimate the effect of abortion on birth rates. Our findings indicate that states legalizing abortion experienced a 5% decline in births relative to other states. The decline among teens, women over 35, and nonwhite women was even greater: 13%, 8%, and 12% respectively. Out-of-wedlock births declined by twice as much as births in wedlock. If legalization in some states affected birth rates in neighboring states (through travel to obtain an abortion), comparing births between states will underestimate the actual reduction. Using more distant comparison states increases the estimated impact of abortion legalization on birth rates to about 8%. Applying this estimate to the current level of births, a complete recriminalization of abortion would result in 320,000 additional births per year.
Field Documentation of Summer and Fall Diet in Thirteen-lined Ground Squirrels, Ictidomys Tridecemlineatus
Prior work has shown a shift in stable carbon isotope values of Ictidomys tridecemlineatus incisors and fecal pellets late in the active season (Jang et al., 2012 and Chacko, 2013).
The purpose of this study was to find out if the diet of I. tridecemlineatus shifts from C3 to C4 plants during the late part of the active season through direct observation of feeding activities. Observations were made at the Andrews University Airpark in SW Michigan from July to late September, 2013.
Representative samples of plant and insect material fed on were collected and analyzed for stable carbon and nitrogen isotopic composition. We found no shift from C3 to C4 plant diet. However, there was a C13 enrichment of plant and insect material over the course of the active season
Quantification of fracture interaction using stress intensity factor variation maps
Accurate and flexible models of fracture interaction are sought after in the fields of mechanics and geology. Stress intensity factors (SIFs) quantify the energy concentrated at the fracture tips and are perturbed from their isolated values when two fractures are close to one another. Using a three-dimensional finite element fracture mechanics code to simulate static fractures in tension and compression, interaction effects are examined. SIF perturbations are characterized by introducing three interaction measures: the circumferential and maximum SIF perturbation provide the “magnitude” of the effect of interaction, and the amplification to shielding ratio quantifies the balance between increased and decreased SIFs along the tip. These measures are used to demonstrate the change in interaction with fracture separation and to find the separation at which interaction becomes negligible. Interaction maps are constructed by plotting the values of the interaction measures for a static fracture as a second fracture is moved around it. These maps are presented for several common fracture orientations in tension. They explore interaction by highlighting regions in which growth is more likely to occur and where fractures will grow into nonplanar geometries. Interaction maps can be applied to fracture networks with multiple discontinuities to analyze the effect of geometric variations on fracture interaction
Age and Synchrony of First Estrus in Gilts as Influenced by Type and Duration of Daily Boar Exposure (BE)
Fence-line boar exposure (FBE) and physical boar exposure (PBE), each with durations of 10 minutes or four hours, were evaluated for their ability to trigger puberty in gilts. Gilts provided PBE attained puberty 11.8 days earlier than gilts provided FBE. Duration of boar contact was without effect. Earlier age at first estrus resulted, in large part, from a more rapid pubertal response after initiation of boar exposure (BE). The mean interval from initiation of BE to pubertal estrus was 13.5 days for PBE gilts and 24.8 days for FBE gilts. Fence-line boar exposure stimulates earlier puberty in gilts (shown in previous studies), but is less effective than PBE for triggering a rapid pubertal response in gilts. Physical boar exposure is required to achieve the maximal pubertal response to boar exposure when applied daily for limited periods (4 hours or less) to gilts nearing onset of puberty
Roadside Memorials in Five South Central Kentucky Counties
Roadside memorials in Allen, Barren, Butler, Edmonson, and Warren Counties in south central Kentucky mark the sites of automobile fatalities. These informal memorials are construced by family or friends of the deceased. Thirty-one memorials are found throughout these five counties. The majority of these memorials take on one of three forms: crosses, crosses with flowers, and standing styrofoam-based flower arrangements. Crosses, particularly white wooden crosses, are the most common element in these memorials. Unlike most death-related material culture studies, this research is built heavily upon interviews and conversations with those who construct and maintain the memorials. Much of the analysis of this thesis consists of in-depth explorations of particular roadside memorials and the meanings they have to those who constructed and maintain them. The memorials are explored within the larger context of regional death memorials in general. This larger context includes personal memorials, cemetery decoration, public memorials, and newspaper memorials
Studies of a Nitrocellulose Silicone Cream as a Skin Protectant against Eczematogenous Contact Allergens1
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