21,055 research outputs found
Quantum optomechanics beyond the quantum coherent oscillation regime
Interaction with a thermal environment decoheres the quantum state of a
mechanical oscillator. When the interaction is sufficiently strong, such that
more than one thermal phonon is introduced within a period of oscillation,
quantum coherent oscillations are prevented. This is generally thought to
preclude a wide range of quantum protocols. Here, we introduce a pulsed
optomechanical protocol that allows ground state cooling, general linear
quantum non-demolition measurements, optomechanical state swaps, and quantum
state preparation and tomography without requiring quantum coherent
oscillations. Finally we show how the protocol can break the usual thermal
limit for sensing of impulse forces.Comment: 6 pages, 3 figure
Big Bang Nucleosynthesis with Independent Neutrino Distribution Functions
We have performed new Big Bang Nucleosynthesis calculations which employ
arbitrarily-specified, time-dependent neutrino and antineutrino distribution
functions for each of up to four neutrino flavors. We self-consistently couple
these distributions to the thermodynamics, the expansion rate and scale
factor-time/temperature relationship, as well as to all relevant weak,
electromagnetic, and strong nuclear reaction processes in the early universe.
With this approach, we can treat any scenario in which neutrino or antineutrino
spectral distortion might arise. These scenarios might include, for example,
decaying particles, active-sterile neutrino oscillations, and active-active
neutrino oscillations in the presence of significant lepton numbers. Our
calculations allow lepton numbers and sterile neutrinos to be constrained with
observationally-determined primordial helium and deuterium abundances. We have
modified a standard BBN code to perform these calculations and have made it
available to the community.Comment: 9 pages, 5 figure
"Mortgage Default Among Rural, Low-Income Borrowers"
In this working paper, Quercia, McCarthy, and Stegman use data obtained on 874 low income, rural borrowers participating in the Section 502 Home Ownership program administered by the Farmer's Home Administration (FmHA), and apply two multivariate proportional hazard models in order to analyze default decisions among these borrowers over time. The authors cite two key findings relating to default literature: (1) that contrary to prior findings, the size of the mortgage payment relative to borrower income plays a significant part in the default decision; and (2) borrower characteristics traditionally deemed risky (including minority status or being a female head of household) had no significant effect on borrower default. Rather, borrower-related factors--such as a change in marital status or the exodus of children from the household--played a larger part in the default decisions of borrowers participating in the FmHA program.
Assessing Domestic Demand for Organic and ‘Locally Grown' Produce on An ‘Organic Island': Dominica's Dilemma
The economy of Dominica faces a unique set of challenges. As with many other Caribbean nations, Dominica has historically been dependent upon agriculture. Over the past several hundred years, the island's economy has been largely supported through the concentrated mono-cropping of a variety of export-oriented crops including coffee, limes, vanilla, and bananas (FAVACA, 2008). Today, approximately 45% of Dominica's labor force is employed in the agricultural sector (FAVACA, 2008). While neighboring countries have economically benefited from tourism, due to its lack of white sand beaches, Dominica is not a typical tourist destination. Taking advantage of its landscape, rainforests, and diversity of natural wildlife, in an effort to diversify its economy Dominica has instead catered to eco-/wellness tourists. Bridging its agricultural foundations with the ecological preservation needed to support its tourist industry, the government of Dominica has signaled its interest in transforming Dominica into an Organic Island (‘Organic Dominica') by 2015. Through this initiative, sustainable, organic agricultural production methods will be encouraged. Complementing this, a ‘Buy Organic, Locally Grown' campaign has been proposed to encourage domestic and regional consumption of Dominica's agricultural outputs and food products. As such, ‘Organic Dominica' has the potential to simultaneously address ongoing national concerns surrounding food security, foreign exchange availability, domestic un/underemployment, and environmental preservation. Before and since proposing this policy, surveys were conducted to identity the major stakeholders in (organic) agricultural production, and current and potential markets for organic production. It remains, however, to quantify Dominica's capacity to produce organic goods, the scale of the potential market, and the price premia that organic production could command. This information is critical to determining the appropriate initial level of producer support and marketing programs required to successfully promote the production and consumption of Dominica's organic outputs and propel Dominica toward the desired status of a model ‘Organic Island'.contingent valuation, willingness to pay, Caribbean, organic, locally grown, food, Agricultural and Food Policy, International Development, Marketing, O13, O54, Q01, Q13, Q18,
DC Resistivity Investigation of Anisotropy and Lateral Effect using Azimuthal Offset Wenner Array. a case Study of the University of Calabar, Nigeria
Azimuthal resistivity survey (ARS) was conducted using offset Wenner array to investigate anisotropy and lateral effect for the first time in the University of Calabar environment, Nigeria. Two (2) sites were surveyed within the study area. Data were collected using ABEM terrameter SAS 1000 and its accessories. From a reference point, azimuth was varied with an increment of 150 to 3600. Analysis of azimuthal offset Wenner array resistivity data revealed that the study area is homogeneously anisotropic with no lateral effect in all azimuths. The apparent coefficient of anisotropy estimated from the field data ranged from 1.10 to 1.90 with anisotropy in (NW-SE), (NE-SW), (E-W) and (N-S) directions. The homogeneity index ranged from 4.71 to 9.60 and this indicates that the variation due to anisotropy is greater than that due to inhomogeneity within the study area. Keywords: Anisotropy, Lateral effect, Azimuthal Resistivity Survey, Offset Wenner Array and homogeneity index
Direct and indirect lactate oxidation in trained and untrained men.
Lactate has been shown to be an important oxidative fuel. We aimed to quantify the total lactate oxidation rate (Rox) and its direct vs. indirect (glucose that is gluconeogenically derived from lactate and subsequently oxidized) components (mg·kg(-1)·min(-1)) during rest and exercise in humans. We also investigated the effects of endurance training, exercise intensity, and blood lactate concentration ([lactate]b) on direct and indirect lactate oxidation. Six untrained (UT) and six trained (T) men completed 60 min of constant load exercise at power outputs corresponding to their lactate threshold (LT). T subjects completed two additional 60-min sessions of constant load exercise at 10% below the LT workload (LT-10%), one of which included a lactate clamp (LC; LT-10%+LC). Rox was higher at LT in T [22.7 ± 2.9, 75% peak oxygen consumption (Vo2peak)] compared with UT (13.4 ± 2.5, 68% Vo2peak, P < 0.05). Increasing [lactate]b (LT-10%+LC, 67% Vo2peak) significantly increased lactate Rox (27.9 ± 3.0) compared with its corresponding LT-10% control (15.9 ± 2.2, P < 0.05). Direct and indirect Rox increased significantly from rest to exercise, and their relative partitioning remained constant in all trials but differed between T and UT: direct oxidation comprised 75% of total lactate oxidation in UT and 90% in T, suggesting the presence of training-induced adaptations. Partitioning of total carbohydrate (CHO) use showed that subjects derived one-third of CHO energy from blood lactate, and exogenous lactate infusion increased lactate oxidation significantly, causing a glycogen-sparing effect in exercising muscle
Chemicals having estrogenic activity can be released from some bisphenol a-free, hard and clear, thermoplastic resins
Background: Chemicals that have estrogenic activity (EA) can potentially cause adverse health effects in mammals
including humans, sometimes at low doses in fetal through juvenile stages with effects detected in adults.
Polycarbonate (PC) thermoplastic resins made from bisphenol A (BPA), a chemical that has EA, are now often
avoided in products used by babies. Other BPA-free thermoplastic resins, some hypothesized or advertised to be
EA-free, are replacing PC resins used to make reusable hard and clear thermoplastic products such as baby bottles.
Methods: We used two very sensitive and accurate in vitro assays (MCF-7 and BG1Luc human cell lines) to quantify
the EA of chemicals leached into ethanol or water/saline extracts of fourteen unstressed or stressed (autoclaving,
microwaving, UV radiation) thermoplastic resins. Estrogen receptor (ER)-dependent agonist responses were confirmed
by their inhibition with the ER antagonist ICI 182,780.
Results: Our data showed that some (4/14) unstressed and stressed BPA-free thermoplastic resins leached chemicals
having significant levels of EA, including one polystyrene (PS), and three Tritanâ„¢ resins, the latter reportedly
EA-free. Exposure to UV radiation in natural sunlight resulted in an increased release of EA from Tritanâ„¢ resins.
Triphenyl-phosphate (TPP), an additive used to manufacture some thermoplastic resins such as Tritanâ„¢, exhibited
EA in both MCF-7 and BG1Luc assays. Ten unstressed or stressed glycol-modified polyethylene terephthalate
(PETG), cyclic olefin polymer (COP) or copolymer (COC) thermoplastic resins did not release chemicals with detectable
EA under any test condition.
Conclusions: This hazard survey study assessed the release of chemicals exhibiting EA as detected by two sensitive,
widely used and accepted, human cell line in vitro assays. Four PC replacement resins (Tritanâ„¢ and PS) released
chemicals having EA. However, ten other PC-replacement resins did not leach chemicals having EA (EA-free-resins).
These results indicate that PC-replacement plastic products could be made from EA-free resins (if appropriate EA-free
additives are chosen) that maintain advantages of re-usable plastic items (price, weight, shatter resistance) without
releasing chemicals having EA that potentially produce adverse health effects on current or future generations.This work was supported by the following NIH/NIEHS grants: R44 ES011469, 01–03 (CZY);
1R43/44 ES014806, 01–03 (CZY); subcontract (CZY, PI) on an NIH Grant 01–03
43/44ES018083-01. This work was also supported by NIH grants to MSD (P42
ES004699), and DJK and SIY (1R43ES018083-01-03, NIEHS 1R44ES019442-01-03
and NIEHS 2R44ES016964-01-03).Neuroscienc
NPV Sensitivity Analysis: A Dynamic Excel Approach
Financial analysts generally create static formulas for the computation of NPV. When they do so, however, it is not readily apparent how sensitive the value of NPV is to changes in multiple interdependent and interrelated variables. It is the aim of this paper to analyze this variability by employing a dynamic, visually graphic presentation using Excel. Our approach illustrates how these variables, when increased or decreased to reflect the potential range of values in a business case, change the value of NPV, and hence affect the decision about whether to proceed with the project or to reject it. Furthermore, since sales revenue is one of the least certain elements in the business case, the presentation includes a probability estimate of whether NPV will be positive or negative, assuming that sales revenue is normally distributed with a known mean and standard deviation. The business case we have chosen for illustrative purposes is a global energy project. Nevertheless, financial analysts in any industry should be able to apply our dynamic spreadsheet approach to their projects as well
- …