Naval Postgraduate School Board of Advisors Subcommittee Meeting 25-26 April 2012

Minutes of the April 2012 BOA Meeting in Monterey, California

Gender Differences Associated With Memory Recall

This study investigated whether a gender difference existed in the context of romantic relationships. Participants rated positively valanced words and negatively valanced words, that were related to a romantic relationship, on how relevant they were to realistic romantic relationships. Participants were then given a free recall task to recall any words that they rated earlier. The study found that a gender difference did exist in the context of negatively valanced words. Women were more successful in recall of negatively valanced words than men. These findings indicate that women encode emotional information differently than men encode emotional information and recall that information more easily than male participants

Competition between structural distortion and magnetic moment formation in fullerene C20_{20}

We investigated the effect of on-site Coulomb interactions on the structural and magnetic ground state of the fullerene C$_{20}$ based on density-functional-theory calculations within the local density approximation plus on-site Coulomb corrections (LDA+$U$). The total energies of the high symmetry ($I_{h}$) and distorted ($D_{3d}$) structures of C$_{20}$ were calculated for different spin configurations. The ground state configurations were found to depend on the forms of exchange-correlation potentials and the on-site Coulomb interaction parameter $U$, reflecting the subtle nature of the competition between Jahn-Teller distortion and magnetic instability in fullerene C$_{20}$. While the non-magnetic state of the distorted $D_{3d}$ structure is robust for small $U$, a magnetic ground state of the undistorted $I_{h}$ structure emerges for $U$ larger than 4 eV when the LDA exchange-correlation potential is employed.Comment: 4 figures, 1 tabl

Electron orbital valves made of multiply connected armchair carbon nanotubes with mirror-reflection symmetry: tight-binding study

Using the tight-binding method and the Landauer-B\"{u}ttiker conductance formalism, we demonstrate that a multiply connected armchair carbon nanotube with a mirror-reflection symmetry can sustain an electron current of the $\pi$-bonding orbital while suppress that of the $\pi$-antibonding orbital over a certain energy range. Accordingly, the system behaves like an electron orbital valve and may be used as a scanning tunneling microscope to probe pairing symmetry in d-wave superconductors or even orbital ordering in solids which is believed to occur in some transition-metal oxides.Comment: 4 figures, 12 page

Factors Affecting Timing and Intensity of Calving Season of Beef Cow-Calf Producers in the Midwest

Despite demonstrated market incentives to adopt controlled calving seasons, many producers still have herds that calve somewhat broadly throughout the year. Primarydata, collected through a coordinated survey effort withUSDA’s National Agricultural Statistics Service, were usedto quantify factors that affect producers’ decisions regardingtiming and intensity of calving season. Ninety-seven, 50, 33,and 26% of farms calve in the spring (Mar, Apr, May),summer (Jun, Jul, Aug), fall (Sep, Oct, Nov), and winter(Dec, Jan, Feb), respectively. Twenty-two percent observeda calving season exclusively in the spring. Sixty-six percentof respondents indicated calving season was dictated byweather, 34% because of labor availability, and 31%because of tradition. Least often reasons for calving seasonwere market timing (16%), feed availability (8%), and other(4%). Producer stated reasons for calving season explained62% of the variation in timing and intensity of calving on anoperation, whereas a model of producer demographic andoperation characteristics explained 83% of the variation.These results highlight the importance of evaluatingproducer and operation characteristics in addition toproducer input when making recommendations to enhanceproduction efficiency and profitability. Furthermore,understanding the factors which impact calving seasonprovides opportunities for improved extension and research programming

Trapping effects on inflation

We develop a Lagrangian approach based on the influence functional method so as to derive self-consistently the Langevin equation for the inflaton field in the presence of trapping points along the inflaton trajectory. The Langevin equation exhibits the backreaction and the fluctuation-dissipation relation of the trapping. The fluctuation is induced by a multiplicative colored noise that can be identified as the the particle number density fluctuations and the dissipation is a new effect that may play a role in the trapping with a strong coupling. In the weak coupling regime, we calculate the power spectrum of the noise-driven inflaton fluctuations for a single trapping point and studied its variation with the trapping location. We also consider a case with closely spaced trapping points and find that the resulting power spectrum is blue.Comment: 13 pages, 2 figure

Progress Report: Effect of Stockpiling Initiation Method on Winter Forage Yield and Quality of Midwestern Cool-season Grass Pastures for Fall-calving Beef Cows

An ongoing two-year trial is being conducted to evaluate the effects of three different methods of initiating forage stockpiling on the quality and mass of forage available over the winter months (October through January). Methods of initiating stockpiling were spring strip-grazing, summer strip-grazing, and summer hay harvest. Forage mass, nutritional, and weather data were input into a ration balancing program with supplemental feed provided to maintain a body condition score (BCS) of five throughout the winter for fall-calving beef cows. Partial budget models were used to evaluate costs associated with the different treatment methods and compared to a standard winter hay feeding regime in a drylot scenario. Spring strip-grazing generated the greatest stockpiled forage mass compared to all other treatments, but also had the lowest dry matter digestibility across sampling dates. There were no differences in crude protein (CP) content among different methods of initiation. The carrying capacity of drylot models was greatest but did not differ between stockpiling models. There was a tendency for drylot models to incur greater total costs ($/ac) than stockpile models. There were no statistical differences in total cost ($/ac) between models using stockpiled forage grazing by different methods of initiation and no statistical differences in gross ($/hd/d) or net ($/hd/d) costs across treatments. While spring strip-grazing resulted in greater forage mass, the quality of this forage was lower than summer treatments. With similar costs, the lower yields from summer stockpiling models (strip-grazing or hay harvest) could be compensated for by the higher nutritional quality of the forage

Considerations for managing beef cows in confinement

Continued volatility of grain markets, coupled with recent summer droughts, has had a significant impact on the Midwestern cow-calf sector in recent years. These factors, along with decreased land availability for grazing and forage production, has resulted in increased cost of production and left many producers pondering alternative management systems for their herds. One such management alternative that is capturing the interest of many producers is the concept of confinement housing of the cow herd. In many parts of the United States, where year-round grazing is either not feasible, or is not implemented, confinement housing of the cow herd is not necessarily a novel practice. Often times, cows are placed on a sacrifice paddock or drylot with varying degrees of access to shelter for a period of time during the winter months, leading up to and sometimes through the calving season. However, with reduced land access and increasing forage prices, an increased proportion of producers are managing cows in confinement during times of the year traditionally devoted to grazing. With these management alterations come various considerations that should be acknowledged

An evaluation of combined geophysical and geotechnical methods to characterize beach thickness

Beaches provide sediment stores and have an important role in the development of the coastline in response to climate change. Quantification of beach thickness and volume is required to assess coastal sediment transport budgets. Therefore, portable, rapid, non-invasive techniques are required to evaluate thickness where environmental sensitivities exclude invasive methods. Site methods and data are described for a toolbox of electrical, electromagnetic, seismic and mechanical based techniques that were evaluated at a coastal site at Easington, Yorkshire. Geophysical and geotechnical properties are shown to be dependent upon moisture content, porosity and lithology of the beach and the morphology of the beach–platform interface. Thickness interpretation, using an inexpensive geographic information system to integrate data, allowed these controls and relationships to be understood. Guidelines for efficient site practices, based upon this case history including procedures and techniques, are presented using a systematic approach. Field results indicated that a mixed sand and gravel beach is highly variable and cannot be represented in models as a homogeneous layer of variable thickness overlying a bedrock half-space