3,534 research outputs found
Delivery of Smoke Toxicants from Cigarettes Made in Developed and Developing Countries: a comparison of U.S. full flavor and ultra light brands with Syrian cigarettes
Clinical research is needed to understand how cigarette toxicant yield affects smoker toxicant exposure. While there is much clinical research on yield and exposure in developed countries, there is little in developing countries. Forty smokers completed one, 4-hour session to compare yield and exposure of different cigarettes. Participants smoked three cigarettes under controlled topography conditions: one U.S. 111 flavor, one U.S. ultra light, and one Syrian cigarette, with 90 minutes between cigarettes. Sessions differed by Syrian brand; 21 participants smoked Alhamraa while 19 smoked A1 Sham cigarettes. Blood nicotine and breath CO samples were obtained, HR was monitored and subjective withdrawal and cigarette effect questions were asked. Results suggest that Syrian Alhamraa and U.S. full flavor were similar in exposure while Syrian A1 Sham and U.S. ultra light were similar. Though U.S. full flavor and ultra light cigarettes differed in toxicant yield and exposure, subjective ratings of withdrawal were similar
Lunar Communication Terminals for NASA Exploration Missions: Needs, Operations Concepts and Architectures
NASA is conducting architecture studies prior to deploying a series of short- and long-duration human and robotic missions for the exploration of the Moon and Mars under the Vision for Space Exploration Initiative. A key objective of these missions is to establish and expand, through a series of launches, a system of systems approach to exploration capabilities and science return. The systems identified were Crew Exploration Vehicles, crew and cargo launch vehicles, crew EVA suits, crew and cargo landers, habitats, mobility carriers, and small, pressurized rovers. Multiple space communication networks and systems, deployed over time, will support these space exploration systems of systems. Each deployment phase will support interoperability of components and provide 20 years of legacy systems. In this paper, we describe the modular lunar communications terminals needed for the emerging lunar mission operational scenarios. These lunar communication terminals require flexibility for use in stationary, integrated, and mobile environments. They will support links directly to Earth, to lunar relay satellites, to astronauts and to fixed and mobile lunar surface systems. The operating concepts and traffic models are presented for these terminals within variety of lunar scenarios. A preliminary architecture is outlined, providing for suitable long-duration operations in the harsh lunar environment
Using Decision Analysis to Improve Malaria Control Policy Making
Malaria and other vector-borne diseases represent a significant and growing burden in many tropical countries. Successfully addressing these threats will require policies that expand access to and use of existing control methods, such as insecticide-treated bed nets (ITNs) and artemesinin combination therapies (ACTs) for malaria, while weighing the costs and benefits of alternative approaches over time. This paper argues that decision analysis provides a valuable framework for formulating such policies and combating the emergence and re-emergence of malaria and other diseases. We outline five challenges that policy makers and practitioners face in the struggle against malaria, and demonstrate how decision analysis can help to address and overcome these challenges. A prototype decision analysis framework for malaria control in Tanzania is presented, highlighting the key components that a decision support tool should include. Developing and applying such a framework can promote stronger and more effective linkages between research and policy, ultimately helping to reduce the burden of malaria and other vector-borne diseases
Spin Dynamics of the Magnetoresistive Pyrochlore Tl_2Mn_2O_7
Neutron scattering has been used to study the magnetic order and spin
dynamics of the colossal magnetoresistive pyrochlore Tl_2Mn_2O_7. On cooling
from the paramagnetic state, magnetic correlations develop and appear to
diverge at T_C (123 K). In the ferromagnetic phase well defined spin waves are
observed, with a gapless ( meV) dispersion relation E=Dq^{2} as
expected for an ideal isotropic ferromagnet. As T approaches T_C from low T,
the spin waves renormalize, but no significant central diffusive component to
the fluctuation spectrum is observed in stark contrast to the
La(Ca,Ba,Sr)MnO system. These results argue strongly that the
mechanism responsible for the magnetoresistive effect has a different origin in
these two classes of materials.Comment: 4 pages (RevTex), 4 figures (encapsulated postscript), to be
published in Phys. Rev. Let
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Forecasting Energy Demand in Large Commercial Buildings Using Support Vector Machine Regression
As our society gains a better understanding of how humans have negatively impacted the environment, research related to reducing carbon emissions and overall energy consumption has become increasingly important. One of the simplest ways to reduce energy usage is by making current buildings less wasteful. By improving energy efficiency, this method of lowering our carbon footprint is particularly worthwhile because it reduces energy costs of operating the building, unlike many environmental initiatives that require large monetary investments. In order to improve the efficiency of the heating, ventilation, and air conditioning (HVAC) system of a Manhattan skyscraper, 345 Park Avenue, a predictive computer model was designed to forecast the amount of energy the building will consume. This model uses Support Vector Machine Regression (SVMR), a method that builds a regression based purely on historical data of the building, requiring no knowledge of its size, heating and cooling methods, or any other physical properties. SVMR employs time-delay coordinates as a representation of the past to create the feature vectors for SVM training. This pure dependence on historical data makes the model very easily applicable to different types of buildings with few model adjustments. The SVM regression model was built to predict a week of future energy usage based on past energy, temperature, and dew point temperature data
Eye Tracking as a Measure of Receptive Vocabulary in Children with Autism Spectrum Disorders
This study examined the utility of eye tracking research technology to measure speech
comprehension in 14 young boys with autism spectrum disorders (ASD) and 15 developmentally
matched boys with typical development. Using eye tracking research technology, children were
tested on individualized sets of known and unknown words, identified based on their performance
on the Peabody Picture Vocabulary Test. Children in both groups spent a significantly longer
amount of time looking at the target picture when previous testing indicated the word was known
(known condition). Children with ASD spent similar amounts of time looking at the target and
non-target pictures when previous testing indicated the word was unknown (unknown condition).
However, children with typical development looked longer at the target pictures in the unknown
condition as well, potentially suggesting emergent vocabulary knowledge
Mean-field model of the ferromagnetic ordering in the superconducting phase of ErNi_2B_2C
A mean-field model explaining most of the details in the magnetic phase
diagram of ErNi_2B_2C is presented. The low-temperature magnetic properties are
found to be dominated by the appearance of long-period commensurate structures.
The stable structure at low temperatures and zero field is found to have a
period of 40 layers along the a direction, and upon cooling it undergoes a
first-order transition at T_C = 2.3 K to a different 40-layered structure
having a net ferromagnetic component of about 0.4 mu_B/Er. The
neutron-diffraction patterns predicted by the two 40-layered structures, above
and below T_C, are in agreement with the observations of Choi et al.Comment: 4 pages, 3 figures (Revtex4
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