Women are not less field independent than men-the role of stereotype threat.

PubMed

Drążkowski, Dariusz; Szwedo, Jakub; Krajczewska, Aleksandra; Adamczuk, Anna; Piątkowski, Krzysztof; Jadwiżyc, Marcin; Rakowski, Adam

2017-10-01

Prior research has shown that females are less field independent (FI) than males. However, when gender identity is salient, performance on tests assessing constructs similar to FI may be hindered, because of stereotype threat. This study examined the impact of stereotype threat on gender differences in FI. We expected that (a) reporting one's own gender prior to FI testing and (b) having an opposite-gender experimenter would activate stereotype threat, and in turn result in lower performance on a test of FI among females. Overall, 170 participants were randomly assigned to one of eight conditions in a between-participants design varying the participant's gender, experimenter's gender and timing of the gender question (before vs. after test). Results showed that reporting one's gender before the FI test led to lower FI performance among females. Furthermore, females achieved higher FI when experimenters were females and gender questions were administered after the FI test. © 2015 International Union of Psychological Science.

Effects of Uncertainties in Electric Field Boundary Conditions for Ring Current Simulations

NASA Astrophysics Data System (ADS)

Chen, Margaret W.; O'Brien, T. Paul; Lemon, Colby L.; Guild, Timothy B.

2018-01-01

Physics-based simulation results can vary widely depending on the applied boundary conditions. As a first step toward assessing the effect of boundary conditions on ring current simulations, we analyze the uncertainty of cross-polar cap potentials (CPCP) on electric field boundary conditions applied to the Rice Convection Model-Equilibrium (RCM-E). The empirical Weimer model of CPCP is chosen as the reference model and Defense Meteorological Satellite Program CPCP measurements as the reference data. Using temporal correlations from a statistical analysis of the "errors" between the reference model and data, we construct a Monte Carlo CPCP discrete time series model that can be generalized to other model boundary conditions. RCM-E simulations using electric field boundary conditions from the reference model and from 20 randomly generated Monte Carlo discrete time series of CPCP are performed for two large storms. During the 10 August 2000 storm main phase, the proton density at 10 RE at midnight was observed to be low (< 1.4 cm-3) and the observed disturbance Dst index is bounded by the simulated Dst values. In contrast, the simulated Dst values during the recovery phases of the 10 August 2000 and 31 August 2005 storms tend to underestimate systematically the observed late Dst recovery. This suggests a need to improve the accuracy of particle loss calculations in the RCM-E model. Application of this technique can aid modelers to make efficient choices on either investing more effort on improving specification of boundary conditions or on improving descriptions of physical processes.

Cognitive Style FD/I: An Important Learner Characteristic for Educational Technologists.

ERIC Educational Resources Information Center

Chinien, Chris A.; Boutin, France

1993-01-01

Reviews the literature on the cognitive style field dependent/field independent (FD/FI) and suggests implications for educational technologists in their efforts to address individual differences among learners during the instructional design process that would narrow the differential learning gain between FD and FI learners. Testing for FD/FI is…

Superconducting spin switch with infinite magnetoresistance induced by an internal exchange field.

PubMed

Li, Bin; Roschewsky, Niklas; Assaf, Badih A; Eich, Marius; Epstein-Martin, Marguerite; Heiman, Don; Münzenberg, Markus; Moodera, Jagadeesh S

2013-03-01

A theoretical prediction by de Gennes suggests that the resistance in a FI/S/FI (where FI is a ferromagnetic insulator, and S is a superconductor) structure will depend on the magnetization direction of the two FI layers. We report a magnetotransport measurement in a EuS/Al/EuS structure, showing that an infinite magnetoresistance can be produced by tuning the internal exchange field at the FI/S interface. This proximity effect at the interface can be suppressed by an Al(2)O(3) barrier as thin as 0.3 nm, showing the extreme confinement of the interaction to the interface giving rise to the demonstrated phenomena.

The 11 Year Solar Cycle Response of the Equatorial Ionization Anomaly Observed by GPS Radio Occultation

NASA Astrophysics Data System (ADS)

Li, King-Fai; Lin, Li-Ching; Bui, Xuan-Hien; Liang, Mao-Chang

2018-01-01

We have retrieved the latitudinal and vertical structures of the 11 year solar cycle modulation on ionospheric electron density using 14 years of satellite-based radio occultation measurements utilizing the Global Positioning System. The densities at the crests of the equatorial ionization anomaly (EIA) in the subtropics near 300 km in 2003 and 2014 (high solar activity with solar 10.7 cm flux, F10.7 ≈ 140 solar flux unit (sfu)) were 3 times higher than that in 2009 (low solar activity F10.7 ≈ 70 sfu). The higher density is attributed to the elevated solar extreme ultraviolet and geomagnetic activity during high solar activity periods. The location of the EIA crests moved 50 km upward and 10° poleward, because of the enhanced E × B force. The EIA in the northern hemisphere was more pronounced than that in the southern hemisphere. This interhemispheric asymmetry is consistent with the effect of enhanced transequatorial neutral wind. The above observations were reproduced qualitatively by the two benchmark runs of the Thermosphere-Ionosphere-Electrodynamics General Circulation Model. In addition, we have studied the impact of the 11 year solar cycle on the 27 day solar cycle response of the ionospheric electron density. Beside the expected modulation on the amplitude of the 27 day solar variation due to the 11 year solar cycle, we find that the altitude of the maximal 27 day solar response is unexpectedly 50 km higher than that of the 11 year solar response. This is the first time that a vertical dependence of the solar responses on different time scales is reported.

Teacher-Student Cognitive Style and Achievement in Biology.

ERIC Educational Resources Information Center

Jolly, Pauline E.; Strawitz, Barbara M.

1984-01-01

Investigated the consequences of teacher-student cognitive style (field dependence- FD and independence- FI) matches and mismatches on student achievement in biology. Results suggest that whereas FI students may be taught by and achieve equally well with either FI or FD teachers, FD students are more successfully taught by FI teachers. (JN)

Sodium Ion Dynamics in the Magnetospheric Flanks of Mercury

NASA Astrophysics Data System (ADS)

Aizawa, Sae; Delcourt, Dominique; Terada, Naoki

2018-01-01

We investigate the transport of planetary ions in the magnetospheric flanks of Mercury. In situ measurements from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft show evidences of Kelvin-Helmholtz instability development in this region of space, due to the velocity shear between the downtail streaming flow of solar wind originating protons in the magnetosheath and the magnetospheric populations. Ions that originate from the planet exosphere and that gain access to this region of space may be transported across the magnetopause along meandering orbits. We examine this transport using single-particle trajectory calculations in model Magnetohydrodynamics simulations of the Kelvin-Helmholtz instability. We show that heavy ions of planetary origin such as Na+ may experience prominent nonadiabatic energization as they E × B drift across large-scale rolled up vortices. This energization is controlled by the characteristics of the electric field burst encountered along the particle path, the net energy change realized corresponding to the maximum E × B drift energy. This nonadiabatic energization also is responsible for prominent scattering of the particles toward the direction perpendicular to the magnetic field.

Exposure to Radiofrequency Electromagnetic Fields From Wi-Fi in Australian Schools

PubMed Central

Karipidis, Ken; Henderson, Stuart; Wijayasinghe, Don; Tjong, Lydiawati; Tinker, Rick

2017-01-01

Abstract The increasing use of Wi-Fi in schools and other places has given rise to public concern that the radiofrequency (RF) electromagnetic fields from Wi-Fi have the potential to adversely affect children. The current study measured typical and peak RF levels from Wi-Fi and other sources in 23 schools in Australia. All of the RF measurements were much lower than the reference levels recommended by international guidelines for protection against established health effects. The typical and peak RF levels from Wi-Fi in locations occupied by children in the classroom were of the order of 10−4 and 10−2% of the exposure guidelines, respectively. Typical RF levels in the classroom were similar between Wi-Fi and radio but higher than other sources. In the schoolyard typical RF levels were higher for radio, TV and mobile phone base stations compared to Wi-Fi. The results of this study showed that the typical RF exposure of children from Wi-Fi at school is very low and comparable or lower to other sources in the environment. PMID:28074013

Exposure to Radiofrequency Electromagnetic Fields From Wi-Fi in Australian Schools.

PubMed

Karipidis, Ken; Henderson, Stuart; Wijayasinghe, Don; Tjong, Lydiawati; Tinker, Rick

2017-08-01

The increasing use of Wi-Fi in schools and other places has given rise to public concern that the radiofrequency (RF) electromagnetic fields from Wi-Fi have the potential to adversely affect children. The current study measured typical and peak RF levels from Wi-Fi and other sources in 23 schools in Australia. All of the RF measurements were much lower than the reference levels recommended by international guidelines for protection against established health effects. The typical and peak RF levels from Wi-Fi in locations occupied by children in the classroom were of the order of 10-4 and 10-2% of the exposure guidelines, respectively. Typical RF levels in the classroom were similar between Wi-Fi and radio but higher than other sources. In the schoolyard typical RF levels were higher for radio, TV and mobile phone base stations compared to Wi-Fi. The results of this study showed that the typical RF exposure of children from Wi-Fi at school is very low and comparable or lower to other sources in the environment. © The Author 2017. Published by Oxford University Press.

Light fidelity (Li-Fi): An effective solution for data transmission

NASA Astrophysics Data System (ADS)

Sharma, Vaishali; Rajput, Shreya; Sharma, Praveen Kumar

2016-03-01

The rapid advancement in the field of science has led to the development of many technologies, gadgets and equipment which in turn has hold pressure on Wi-Fi, modems, board band connections etc., to lessen this stress new revolution in this field has rooted on termed "LI-FI". Li-Fi stands for light fidelity i.e. light is used for the transmission of data. The concept of Li-Fi is taking the fiber out of fiber optics sending information through an LED that varies in intensity faster than human eye can follow. Li-Fi offers an entirely new paradigm in wireless technology in term of communication, speed, flexibility, usability etc. The idea of data through illumination is similar to radio waves communication difference lies in the use of LED in LI-Fi, which made it superior than Wi-Fi. Hence Li-Fi is linked to the visible light communication network provision transmission which is looked upon as an advancement. Thus a new class of light with high intensity light source of solid state design bringing clean lighting solution to general and specialty lighting. With energy efficiency, long useful lifetime, full spectrum and dimming. Li-Fi is just not only confined to light and LED indeed it is a platform with versatile advantages and facilities. This paper gives a brief idea about the introduction of Li-Fi, its working, advantages, limitations etc.

76 FR 12717 - Disability and Rehabilitation Research Projects and Centers Program; Field Initiated (FI...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-08

... DEPARTMENT OF EDUCATION Disability and Rehabilitation Research Projects and Centers Program; Field...; National Institute on Disability and Rehabilitation Research (NIDRR)--Disability and Rehabilitation Research Projects and Centers Program--Field Initiated (FI) Projects AGENCY: Office of Special Education...

Electron Jet Detected by MMS at Dipolarization Front

NASA Astrophysics Data System (ADS)

Liu, C. M.; Fu, H. S.; Vaivads, A.; Khotyaintsev, Y. V.; Gershman, D. J.; Hwang, K.-J.; Chen, Z. Z.; Cao, D.; Xu, Y.; Yang, J.; Peng, F. Z.; Huang, S. Y.; Burch, J. L.; Giles, B. L.; Ergun, R. E.; Russell, C. T.; Lindqvist, P.-A.; Le Contel, O.

2018-01-01

Using MMS high-resolution measurements, we present the first observation of fast electron jet (Ve 2,000 km/s) at a dipolarization front (DF) in the magnetotail plasma sheet. This jet, with scale comparable to the DF thickness ( 0.9 di), is primarily in the tangential plane to the DF current sheet and mainly undergoes the E × B drift motion; it contributes significantly to the current system at the DF, including a localized ring-current that can modify the DF topology. Associated with this fast jet, we observed a persistent normal electric field, strong lower hybrid drift waves, and strong energy conversion at the DF. Such strong energy conversion is primarily attributed to the electron-jet-driven current (E ṡ je ≈ 2 E ṡ ji), rather than the ion current suggested in previous studies.

Electric-Field-Induced Alignment of Block Copolymer/Nanoparticle Blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liedel, Clemens; Schindler, Kerstin; Pavan, Mariela J.

External electric fi elds readily align birefringent block-copolymer mesophases. In this study the effect of gold nanoparticles on the electric-fi eld-induced alignment of a lamellae-forming polystyrene- block -poly(2-vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric-fi eldassisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such fi lms under benign experimental conditions.

Raindrop Size Distribution Measurements at 4,500 m on the Tibetan Plateau During TIPEX-III

NASA Astrophysics Data System (ADS)

Chen, Baojun; Hu, Zhiqun; Liu, Liping; Zhang, Guifu

2017-10-01

As part of the third Tibetan Plateau Atmospheric Scientific Experiment field campaign, raindrop size distribution (DSD) measurements were taken with a laser optical disdrometer in Naqu, China, at 4,508 m above sea level (asl) during the summer months of 2013, 2014, and 2015. The characteristics of DSDs for five different rain rates, for two rain types (convective and stratiform), and for daytime and nighttime rains were studied. The shapes of the averaged DSDs were similar for different rain rates, and the width increased with rainfall intensity. Little difference was found in stratiform DSDs between day and night, whereas convective DSDs exhibited a significant day-night difference. Daytime convective DSDs had larger mass-weighted mean diameters (Dm) and smaller generalized intercepts (NW) than the nighttime DSDs. The constrained relations between the intercept N0 and shape μ, slope Λ and μ, and NW and Dm of gamma DSDs were derived. We also derived empirical relations between Dm and the radar reflectivity factor in the Ku and Ka bands.

Dayside response of the magnetosphere to a small shock compression: Van Allen Probes, Magnetospheric MultiScale, and GOES-13

NASA Astrophysics Data System (ADS)

Cattell, C.; Breneman, A.; Colpitts, C.; Dombeck, J.; Thaller, S.; Tian, S.; Wygant, J.; Fennell, J.; Hudson, M. K.; Ergun, Robert; Russell, C. T.; Torbert, Roy; Lindqvist, Per-Arne; Burch, J.

2017-09-01

Observations from Magnetospheric MultiScale ( 8 Re) and Van Allen Probes ( 5 and 4 Re) show that the initial dayside response to a small interplanetary shock is a double-peaked dawnward electric field, which is distinctly different from the usual bipolar (dawnward and then duskward) signature reported for large shocks. The associated E × B flow is radially inward. The shock compressed the magnetopause to inside 8 Re, as observed by Magnetospheric MultiScale (MMS), with a speed that is comparable to the E × B flow. The magnetopause speed and the E × B speeds were significantly less than the propagation speed of the pulse from MMS to the Van Allen Probes and GOES-13, which is consistent with the MHD fast mode. There were increased fluxes of energetic electrons up to several MeV. Signatures of drift echoes and response to ULF waves also were seen. These observations demonstrate that even very weak shocks can have significant impact on the radiation belts.

LONG-TERM ELECTROMAGNETIC FIELD MEASUREMENT AND ASSESSMENT FOR A SHOPPING MALL.

PubMed

Engiz, Begum Korunur; Kurnaz, Cetin

2017-07-01

As a result of the dense deployment of wireless devices and base stations, measuring and evaluating the electromagnetic (EM) exposure levels they emit have become important to human health especially if they exceed the limits defined in the standards. Base stations, Wi-Fi equipment and other electronic devices are used heavily, especially in densely crowded places like shopping centers. In this study, electric field strength (E) measurements were conducted at one of the largest shopping malls in Turkey. Broadband E measurements were performed using PMM 8053 EM field strength meter for 24 h a day for the duration of one week while frequency selective measurements were carried out with SRM-3006 EM field strength meter. It is concluded from the measurements that the mean measured total E in the band between 100 kHz and 3 GHz is 0.59 V/m while the maximum E is 7.88 V/m, which are both below the limit determined by International Commission on Non-Ionizing Radiation Protection. Evolutions show that E can increase by up to 55% during the daytime. Analyses demonstrate that 71.3% of total E is caused by UMTS2100, 16.3% is produced by GSM900, 6.2% by LTE, 3.5% by Wi-Fi, and 2.7% is generated by devices that use the remaining frequency bands. Based on the detailed statistical analysis of long-term E measurement results, it can be concluded that the measured E levels are not in normal distribution and that they are statistically different with respect to days. Furthermore, distribution of E can be best modeled with the non-parametric approach. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Interhemispheric Asymmetry of the Sunward Plasma Flows for Strongly Dominant IMF BZ > 0

NASA Astrophysics Data System (ADS)

Yakymenko, K. N.; Koustov, A. V.; Fiori, R. A. D.

2018-01-01

Super Dual Auroral Radar Network (SuperDARN) convection maps obtained simultaneously in both hemispheres are averaged to infer polar cap ionospheric flow patterns under strongly dominant positive interplanetary magnetic field (IMF) Bz component. The data set consisted of winter observations in the Northern Hemisphere simultaneously with summer observations in the Southern Hemisphere. Long-lasting high-latitude dayside reverse convection cells are shown to have faster sunward flows at near-magnetic noon hours in the summer/Southern Hemisphere. Sunward flows typically deviate from the midnight-noon meridian toward 10-11 h of magnetic local time in the summer/Southern Hemisphere and are more aligned with the midnight-noon meridian in the winter/Northern Hemisphere. Flow deviations in the winter/Northern Hemisphere can be both toward prenoon and postnoon hours, and there is no clear relationship between flow deviation and the IMF By component. No strong preference for the sunward flow occurrence depending on the IMF Bx polarity was found. In addition, the rate of the sunward flow speed increase in response to an increase in driving conditions was found to be comparable for the IMF Bx > 0 and Bx < 0.

Conditioning Electron Beams in the Ion-Focused Regime

DTIC Science & Technology

1992-09-17

other adverse effects from ion motion. Even when ion ionization is important, the increase in fi is usually not the explosive growth described by...M. Fawley, D. Prosnitz and A. G. Cole, Phys. Rev. Lett. 54, 685 (1985). 13. D. S. Prono, IEEE Trans. Nucl. Sci. NS-32, 3144 (1985). 14. G. J

Nightside Magnetosphere-Ionosphere Current Circuit: Implications for Auroral Streamers and Pi2 Pulsations

NASA Astrophysics Data System (ADS)

Ohtani, S.; Uozumi, T.

2018-01-01

We investigate the electrodynamic coupling of the nightside magnetosphere-ionosphere system using the analogy of a current circuit. In our model circuit the generator drives a constant current, which flows through the magnetotail and ionosphere branches. The magnetotail branch has a capacitor C and resistor RT, whereas the ionospheric branch has an inductor L and resistor RI. Each element is physically described with local quantities and geometries. For RT ≪ RI the electric circuit is characterized by three time constants: τCR(=CRT), τLC= LC, and τL/R(=L/RI). It is found that τCR is of the order of the ion gyroperiod in the plasma sheet, and τLC and τL/R correspond to the eigenperiod and decay time of the field line oscillation, respectively. Therefore, despite the variability of each circuit element, τCR ≪ τLC ≪ τL/R holds generally. It is found that under this condition the current circuit is characterized as overdamped, and its decay time constant is given by τL/R. RI is smaller, and therefore, τL/R is longer as the structure is more elongated in the direction of convection. This may explain why the auroral streamers, which are considered to be the ionospheric manifestation of fast flows in the plasma sheet, last significantly longer than the flows themselves. Another application is the Pi2 pulsations at the substorm onsets. If RT increases by a factor of τLC/τCR, the system indeed becomes underdamped, and the oscillation period is given by 2πτLC. It is suggested that the substorm initiation is a distinct process with a significant enhancement of tail resistivity in a localized area.

Light fidelity (Li-Fi): An effective solution for data transmission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Vaishali, E-mail: vaishalisharma202@gmail.com; Rajput, Shreya, E-mail: rajputshreya15@gmail.com; Sharma, Praveen Kumar, E-mail: psv.bkbiet@gmail.com

The rapid advancement in the field of science has led to the development of many technologies, gadgets and equipment which in turn has hold pressure on Wi-Fi, modems, board band connections etc., to lessen this stress new revolution in this field has rooted on termed “LI-FI”. Li-Fi stands for light fidelity i.e. light is used for the transmission of data. The concept of Li-Fi is taking the fiber out of fiber optics sending information through an LED that varies in intensity faster than human eye can follow. Li-Fi offers an entirely new paradigm in wireless technology in term of communication,more » speed, flexibility, usability etc. The idea of data through illumination is similar to radio waves communication difference lies in the use of LED in LI-Fi, which made it superior than Wi-Fi. Hence Li-Fi is linked to the visible light communication network provision transmission which is looked upon as an advancement. Thus a new class of light with high intensity light source of solid state design bringing clean lighting solution to general and specialty lighting. With energy efficiency, long useful lifetime, full spectrum and dimming. Li-Fi is just not only confined to light and LED indeed it is a platform with versatile advantages and facilities. This paper gives a brief idea about the introduction of Li-Fi, its working, advantages, limitations etc.« less

Study of Simvastatin Self-Association Using Electrospray-Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Vetrova, E. V.; Lekar, A. V.; Filonova, O. V.; Borisenko, S. N.; Maksimenko, E. V.; Borisenko, N. I.

2015-07-01

Self-association of simvastatin, which is widely used to treat coronary heart disease, was investigated using electrospray-ionization mass spectrometry. Formation of simvastatin self-associates in various solvents was demonstrated using mass spectrometry. Solvation effects were shown to play a special role in the formation of the self-associates. Self-associates containing from two to fi ve simvastatin molecules were detected in mass spectra of an aqueous MeOH (20%) solution of simvastatin. The formation of simvastatin self-associates could compete with the complexation of supramolecular structures during the synthesis of new generation drugs.

No Effects of Acute Exposure to Wi-Fi Electromagnetic Fields on Spontaneous EEG Activity and Psychomotor Vigilance in Healthy Human Volunteers.

PubMed

Zentai, Norbert; Csathó, Árpád; Trunk, Attila; Fiocchi, Serena; Parazzini, Marta; Ravazzani, Paolo; Thuróczy, György; Hernádi, István

2015-12-01

Mobile equipment use of wireless fidelity (Wi-Fi) signal modulation has increased exponentially in the past few decades. However, there is inconclusive scientific evidence concerning the potential risks associated with the energy deposition in the brain from Wi-Fi and whether Wi-Fi electromagnetism interacts with cognitive function. In this study we investigated possible neurocognitive effects caused by Wi-Fi exposure. First, we constructed a Wi-Fi exposure system from commercial parts. Dosimetry was first assessed by free space radiofrequency field measurements. The experimental exposure system was then modeled based on real geometry and physical characteristics. Specific absorption rate (SAR) calculations were performed using a whole-body, realistic human voxel model with values corresponding to conventional everyday Wi-Fi exposure (peak SAR10g level was 99.22 mW/kg with 1 W output power and 100% duty cycle). Then, in two provocation experiments involving healthy human volunteers we tested for two hypotheses: 1. Whether a 60 min long 2.4 GHz Wi-Fi exposure affects the spectral power of spontaneous awake electroencephalographic (sEEG) activity (N = 25); and 2. Whether similar Wi-Fi exposure modulates the sustained attention measured by reaction time in a computerized psychomotor vigilance test (PVT) (N = 19). EEG data were recorded at midline electrode sites while volunteers watched a silent documentary. In the PVT task, button press reaction time was recorded. No measurable effects of acute Wi-Fi exposure were found on spectral power of sEEG or reaction time in the psychomotor vigilance test. These results indicate that a single, 60 min Wi-Fi exposure does not alter human oscillatory brain function or objective measures of sustained attention.

Quantitative, spectrally-resolved intraoperative fluorescence imaging

PubMed Central

Valdés, Pablo A.; Leblond, Frederic; Jacobs, Valerie L.; Wilson, Brian C.; Paulsen, Keith D.; Roberts, David W.

2012-01-01

Intraoperative visual fluorescence imaging (vFI) has emerged as a promising aid to surgical guidance, but does not fully exploit the potential of the fluorescent agents that are currently available. Here, we introduce a quantitative fluorescence imaging (qFI) approach that converts spectrally-resolved data into images of absolute fluorophore concentration pixel-by-pixel across the surgical field of view (FOV). The resulting estimates are linear, accurate, and precise relative to true values, and spectral decomposition of multiple fluorophores is also achieved. Experiments with protoporphyrin IX in a glioma rodent model demonstrate in vivo quantitative and spectrally-resolved fluorescence imaging of infiltrating tumor margins for the first time. Moreover, we present images from human surgery which detect residual tumor not evident with state-of-the-art vFI. The wide-field qFI technique has broad implications for intraoperative surgical guidance because it provides near real-time quantitative assessment of multiple fluorescent biomarkers across the operative field. PMID:23152935

Electromagnetic immunity of implantable pacemakers exposed to wi-fi devices.

PubMed

Mattei, Eugenio; Censi, Federica; Triventi, Michele; Calcagnini, Giovanni

2014-10-01

The purpose of this study is to evaluate the potential for electromagnetic interference (EMI) and to assess the immunity level of implantable pacemakers (PM) when exposed to the radiofrequency (RF) field generated by Wi-Fi devices. Ten PM from five manufacturers, representative of what today is implanted in patients, have been tested in vitro and exposed to the signal generated by a Wi-Fi transmitter. An exposure setup that reproduces the actual IEEE 802.11b/g protocol has been designed and used during the tests. The system is able to amplify the Wi-Fi signal and transmits at power levels higher than those allowed by current international regulation. Such approach allows one to obtain, in case of no EMI, a safety margin for PM exposed to Wi-Fi signals, which otherwise cannot be derived if using commercial Wi-Fi equipment. The results of this study mitigate concerns about using Wi-Fi devices close to PM: none of the PM tested exhibit any degradation of their performance, even when exposed to RF field levels five times higher than those allowed by current international regulation (20 W EIRP). In conclusion, Wi-Fi devices do not pose risks of EMI to implantable PM. The immunity level of modern PM is much higher than the transmitting power of RF devices operating at 2.4 GHz.

Flash propagation and inferred charge structure relative to radar-observed ice alignment signatures in a small Florida mesoscale convective system

NASA Astrophysics Data System (ADS)

Biggerstaff, Michael I.; Zounes, Zackery; Addison Alford, A.; Carrie, Gordon D.; Pilkey, John T.; Uman, Martin A.; Jordan, Douglas M.

2017-08-01

A series of vertical cross sections taken through a small mesoscale convective system observed over Florida by the dual-polarimetric SMART radar were combined with VHF radiation source locations from a lightning mapping array (LMA) to examine the lightning channel propagation paths relative to the radar-observed ice alignment signatures associated with regions of negative specific differential phase (KDP). Additionally, charge layers inferred from analysis of LMA sources were related to the ice alignment signature. It was found that intracloud flashes initiated near the upper zero-KDP boundary surrounding the negative KDP region. The zero-KDP boundary also delineated the propagation path of the lightning channel with the negative leaders following the upper boundary and positive leaders following the lower boundary. Very few LMA sources were found in the negative KDP region. We conclude that rapid dual-polarimetric radar observations can diagnose strong electric fields and may help identify surrounding regions of charge.

System on chip (SOC) wi-fi microcontroller for multistation measurement of water surface level using ultrasonic sensor

NASA Astrophysics Data System (ADS)

Suryono, Suryono; Purnomo Putro, Sapto; Widowati; Adhy, Satriyo

2018-05-01

Experimental results of data acquisition and transmission of water surface level from the field using System on Chip (SOC) Wi-Fi microcontroller are described here. System on Chip (SOC) Wi-Fi microcontroller is useful in dealing with limitations of in situ measurement by people. It is expected to address the problem of field instrumentation such as complexities in electronic circuit, power supply, efficiency, and automation of digital data acquisition. The system developed here employs five (5) nodes consisting of ultrasonic water surface level sensor using (SOC) Wi-Fi microcontroller. The five nodes are connected to a Wi-Fi router as the gateway to send multi-station data to a computer host. Measurement of water surface level using SOC Wi-Fi microcontroller manages conduct multi-station communication via database service programming that is capable of inputting every data sent to the database record according to the identity of data sent. The system here has a measurement error of 0.65 cm, while in terms of range, communication between data node to gateway varies in distance from 25 m to 45 m. Communication has been successfully conducted from one Wi-Fi gateway to the other that further improvement for its multi-station range is a certain possibility.

Aeolian saltation on Mars at low wind speeds

NASA Astrophysics Data System (ADS)

Sullivan, R.; Kok, J. F.

2017-10-01

Laboratory experiments indicate that the fluid threshold friction speed, u*tf, required to initiate fully developed aeolian saltation is much higher on Mars than on Earth. A discrepancy exists between Mars climate models that do not predict winds this strong and observations that sand-sized particles are indeed moving. This paper describes how wind friction speeds well below u*tf, but above the impact threshold, u*ti, required to sustain saltation, can initiate sustained saltation on Mars, but at relatively low flux. Numerical experiments indicate that a sand grain on Mars mobilized sporadically between u*ti and u*tf will develop, over fetch lengths longer than generally available within low-pressure wind tunnels, trajectories capable of splashing grains that propagate saltation and collectively form a cluster of saltating grains that migrate downwind together. The passage of a saltation cluster should leave behind a narrow zone of affected surface grains. The cumulative effect of many clusters represents a low-flux phenomenon that should produce slow changes to aeolian bedforms over periods in which winds remain close to u*ti and never or rarely reach u*tf. Field evidence from small impact ripples along rover traverses is consistent with effects of saltation at these low friction speeds, without obvious evidence for events ≥u*tf. The potential utility of this grain mobility process is that it can operate entirely at more common winds well below u*tf and so help explain widespread sand movements observed on Mars wherever evidence might be mostly absent for u*tf being exceeded.

Loneliness, Coping Strategies and Cognitive Styles of the Gifted Rural Adolescent.

ERIC Educational Resources Information Center

Woodward, John C.; Kalyan-Masih, Violet

1990-01-01

Investigated loneliness, coping, and cognitive styles of 52 gifted rural adolescents. Found that field independent (FI) adolescents were more lonely in a crowd, whereas field dependent (FD) adolescents were more lonely when not with others. FI adolescents showed more autonomy and self-reliance, while FD adolescents relied more on external sources…

RF Exposure Analysis for Multiple Wi-Fi Devices In Enclosed Environment

NASA Technical Reports Server (NTRS)

Hwu, Shian U.; Rhodes, Bryan A.; deSilva, B. Kanishka; Sham, Catherine C.; Keiser, James R.

2013-01-01

Wi-Fi devices operated inside a metallic enclosure have been investigation in the recent years. A motivation for this study is to investigate wave propagation inside an enclosed environment such as elevator, car, aircraft, and spacecraft. There are performances and safety concerned that when the RF transmitters are used in the metallic enclosed environments. In this paper, the field distributions inside a confined room were investigated with multiple portable Wi-Fi devices. Computer simulations were performed using the rigorous computational electromagnetics (CEM). The method of moments (MoM) was used to model the mutual coupling among antennas. The geometrical theory of diffraction (GTD) was applied for the multiple reflections off the ground and walls. The prediction of the field distribution inside such environment is useful for the planning and deployment of a wireless radio and sensor system. Factors that affect the field strengths and distributions of radio waves in confined space were analyzed. The results could be used to evaluate the RF exposure safety in confined environment. By comparing the field distributions for various scenarios, it was observed that the Wi-Fi device counts, spacing and relative locations in the room are important factors in such environments. The RF Keep Out Zone (KOZ), where the electric field strengths exceed the permissible RF exposure limit, could be used to assess the RF human exposure compliance. As shown in this study, it s possible to maximize or minimize field intensity in specific area by arranging the Wi-Fi devices as a function of the relative location and spacing in a calculated manner.

Health Literacy and Emotional Responses Related to Fecal Incontinence

PubMed Central

Patel, Kristina; Bliss, Donna Z.; Savik, Kay

2017-01-01

Purpose The primary purpose was to begin to examine continence literacy of individuals with fecal incontinence (FI) by describing terms by which these individuals referred to FI and to explore their emotional responses to FI. A secondary aim was to compare differences in these results between male versus female and younger (< 65 yrs) versus older persons with FI. Design Secondary analysis of data collected prospectively in a clinical trial of fiber supplementation for FI. Methods Content analysis of participants’ statements reported in field notes of data collectors and their responses to data forms and questions. Results Six thematic categories of terms for FI emerged. Only one person used the term “fecal incontinence.” Alternate terms described stool characteristics, named other gastrointestinal problems, or referred to FI using a term that seemed to depersonalize the problems. Emotional responses to FI focused on the influence of bothersome symptoms of FI, interference with social activities, and need for control. Others showed use of humor for coping and emotional benefits gained from being in a study. Women were impacted by the social limitations of having FI more than men. Younger people expressed feelings of emotional upset. Conclusion There is need to increase health literacy about fecal incontinence. Continence nurse specialists are well qualified to educate patients about FI and to evaluate if higher continence literacy increases reporting of FI. Understanding the various emotional responses to FI may guide the optimal support that nurses can provide and facilitate better management of FI. PMID:20075695

WiFi in Schools, Electromagnetic Fields and Cell Phones: Alberta Health Fact Sheet

ERIC Educational Resources Information Center

Alberta Education, 2012

2012-01-01

Wireless devices and the networks that support them are becoming more common in Alberta schools. WiFi is a wireless networking technology that allows computers and other devices to communicate over a wireless signal. Typically the signal is carried by radio waves over an area of up to 100 meters. Through the implementation of a WiFi network,…

The Refinement of The Preliminary Genetic Decomposition of Group

NASA Astrophysics Data System (ADS)

Wijayanti, K.

2017-04-01

Mathematics proof is one of the characteristics of advanced mathematics thinking, and proof plays an important role in learning the abstract algebra included group theory. The depth and complexity of individual’s understanding of a concept depend on his/her ability to establish connections among the mental structure that constitute it. One of the cognitive styles is field dependent/independent. Field independent (FI) and field dependent (FD) learners have different characteristics. Our research question is (1)How is the proposed refinement of preliminary genetic decomposition of group that is designed with a preliminary study of the learning with APOS works; (2) What understanding about group that is generated by student (Field Independent, Field Neutral, and Field Dependent) when learning through designed material. This study was a descriptive qualitative. The participants of this study were nine (9) undergraduate students who were taking Introduction of Algebraic Structure 1, which included group, in the even semester of academic year 2015/2016 at Universitas Negeri Semarang. Each of type of cognitive styles consisted of 3 participants. There were two instruments used to gather data: written examination in the course and a set of the interview. The FD and FN participants generated Action for a binary operation. The FI participant generated Action and Process for a binary operation. The FD, FN and FI participants generated Action, Process, Object, and Scheme for the set. The FD and FN participant did not generate mental structure for axiom. The FI participant generated Scheme for axiom. The FD, FN and FI participants tend to have no Coherence of Scheme of the group. Not all mental structure on the refinement of the preliminary genetic decomposition can be constructed by participants so well that there are still obstacles in the process of proving.

The Relationship between Learning Style, Academic Major, and Academic Performance of College Students.

ERIC Educational Resources Information Center

Cano, Jamie

1999-01-01

Results of the Group Embedded Figures Test and Myers Briggs Type Indicator for 178 agricultural education freshmen showed 56% were field independent (FI); field dependent (FD) and FI students differed in choice of major; FD students were more likely to have lower grade point average; and as their style moved from dependence to independence, grade…

A novel prediction method about single components of analog circuits based on complex field modeling.

PubMed

Zhou, Jingyu; Tian, Shulin; Yang, Chenglin

2014-01-01

Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments.

Prenatal exposure to non-ionizing radiation: effects of WiFi signals on pregnancy outcome, peripheral B-cell compartment and antibody production.

PubMed

Sambucci, Manolo; Laudisi, Federica; Nasta, Francesca; Pinto, Rosanna; Lodato, Rossella; Altavista, Pierluigi; Lovisolo, Giorgio Alfonso; Marino, Carmela; Pioli, Claudio

2010-12-01

During embryogenesis, the development of tissues, organs and systems, including the immune system, is particularly susceptible to the effects of noxious agents. We examined the effects of prenatal (in utero) exposure to WiFi signals on pregnancy outcome and the immune B-cell compartment, including antibody production. Sixteen mated (plug-positive) female mice were assigned to each of the following groups: cage control, sham-exposed and microwave-exposed (WiFi signals at 2.45 GHz, whole body, SAR 4 W/kg, 2 h/day, 14 consecutive days starting 5 days after mating). No effects due to exposure to WiFi signals during pregnancy on mating success, number of newborns/mother and body weight at birth were found. Newborn mice were left to grow until 5 or 26 weeks of age, when immunological analyses were performed. No differences due to exposure were found in spleen cell number, B-cell frequency or antibody serum levels. When challenged in vitro with LPS, B cells from all groups produced comparable amounts of IgM and IgG, and proliferated at a similar level. All these findings were consistently observed in the female and male offspring at both juvenile (5 weeks) and adult (26 weeks) ages. Stress-associated effects as well as age- and/or sex-related differences were observed for several parameters. In conclusion, our results do not show any effect on pregnancy outcome or any early or late effects on B-cell differentiation and function due to prenatal exposure to WiFi signals.

Magnetic field effects on electron transfer reactions involving sextet-spin ( S = 5/2) intermediates generated on photoexcitation of a Cr(III)-porphyrin complex

NASA Astrophysics Data System (ADS)

Mori, Yukie; Hoshino, Mikio; Hayashi, Hisaharu

The excited trip-sextet ( 6 T 1 ) state of chloro-(3-methylimidazol)-( meso -tetraphenylporphyrinato) chromium(III) (Cr III P) is quenched by 1,1 '-dibenzyl-4,4 '-bipyridinium (BV 2+ ) in acetonitrile through electron transfer to give 5 (Cr III P .+ ) and 2 BV .+ . The intermediate is a geminate ion pair in the sextet (Sx) state 6 [ 5 (Cr III P .+ ) 2 BV .+ ], which decays through either the escape from a solvent cage to give the free ions or the spin conversion to the quartet (Qa) state followed by back electron transfer. The free ion yield ( ΦFI ) increased with increasing magnetic field from 0 to 4 T and then slightly decreased from 4 T to 10 T. These magnetic field effects are explained as follows. Under low fields where the Zeeman splitting of the spin sublevels is lower than or comparable with the electron spin dipole-dipole interaction within 5 (Cr III P .+ ), this interaction effectively induces the Sx ⇔Qa conversion of [ 5 (Cr III P .+ ) 2 BV + ] to result in low ΦFI values. Under high fields where the Zeeman splitting is larger than the dipole-dipole interaction, the Sx Qa conversion is decreased with increasing field to cause higher ΦFI values. The slight decrease in ΦFI above 4 T may be due to the Δg mechanism.

Spatial Distribution and Semiannual Variation of Cold-Dense Plasma Sheet

NASA Astrophysics Data System (ADS)

Bai, Shichen; Shi, Quanqi; Tian, Anmin; Nowada, Motoharu; Degeling, Alexander W.; Zhou, Xu-Zhi; Zong, Qiu-Gang; Rae, I. Jonathan; Fu, Suiyan; Zhang, Hui; Pu, Zuyin; Fazakerly, Andrew N.

2018-01-01

The cold-dense plasma sheet (CDPS) plays an important role in the entry process of the solar wind plasma into the magnetosphere. Investigating the seasonal variation of CDPS occurrences will help us better understand the long-term variation of plasma exchange between the solar wind and magnetosphere, but any seasonal variation of CDPS occurrences has not yet been reported in the literature. In this paper, we investigate the seasonal variation of the occurrence rate of CDPS using Geotail data from 1996 to 2015 and find a semiannual variation of the CDPS occurrences. Given the higher probability of solar wind entry under stronger northward interplanetary magnetic field (IMF) conditions, 20 years of IMF data (1996-2015) are used to investigate the seasonal variation of IMF Bz under northward IMF conditions. We find a semiannual variation of IMF Bz, which is consistent with the Russell-McPherron (R-M) effect. We therefore suggest that the semiannual variation of CDPS may be related to the R-M effect.

Magnetostatic Field System for Uniform Cell Cultures Exposure

PubMed Central

Vergallo, Cristian; Piccoli, Claudia; Romano, Alberto; Panzarini, Elisa; Serra, Antonio; Manno, Daniela; Dini, Luciana

2013-01-01

The aim of the present work has been the design and the realization of a Magnetostatic Field System for Exposure of Cell cultures (MaFiSEC) for the uniform and the reproducible exposure of cell cultures to static magnetic fields (SMFs) of moderate magnetic induction. Experimental and computer-simulated physical measurements show that MaFiSEC: i) generates a SMF with magnetic induction that can be chosen in the range of 3 to 20 mT; ii) allows the uniform SMF exposure of cells growing in adhesion and in suspension; iii) is cheap and easy to use. The efficacy and reproducibility of MaFiSEC has been tested by comparing the biological effects exerted on isolated human lymphocytes by 72 h of exposure to a magnet (i.e. Neodymium Magnetic Disk, NMD) placed under the culture Petri dish. Lymphocytes morphology, viability, cell death, oxidative stress and lysosomes activity were the parameters chosen to evaluate the SMF biological effects. The continuous exposure of cells to a uniform SMF, achieved with MaFiSEC, allows highly reproducible biochemical and morphological data. PMID:23977284

A Magnetohydrodynamic Modeling of the Interchange Cycle for Oblique Northward Interplanetary Magnetic Field

NASA Astrophysics Data System (ADS)

Watanabe, Masakazu; Fujita, Shigeru; Tanaka, Takashi; Kubota, Yasubumi; Shinagawa, Hiroyuki; Murata, Ken T.

2018-01-01

We perform numerical modeling of the interchange cycle in the magnetosphere-ionosphere convection system for oblique northward interplanetary magnetic field (IMF). The interchange cycle results from the coupling of IMF-to-lobe reconnection and lobe-to-closed reconnection. Using a global magnetohydrodynamic simulation code, for an IMF clock angle of 20° (measured from due north), we successfully reproduced the following features of the interchange cycle. (1) In the ionosphere, for each hemisphere, there appears a reverse cell circulating exclusively in the closed field line region (the reciprocal cell). (2) The topology transition of the magnetic field along a streamline near the equatorial plane precisely represents the magnetic flux reciprocation during the interchange cycle. (3) Field-aligned electric fields on the interplanetary-open separatrix and on the open-closed separatrix are those that are consistent with IMF-to-lobe reconnection and lobe-to-closed reconnection, respectively. These three features prove the existence of the interchange cycle in the simulated magnetosphere-ionosphere system. We conclude that the interchange cycle does exist in the real solar wind-magnetosphere-ionosphere system. In addition, the simulation revealed that the reciprocal cell described above is not a direct projection of the diffusion region as predicted by the "vacuum" model in which diffusion is added a priori to the vacuum magnetic topology. Instead, the reciprocal cell is a consequence of the plasma convection system coupled to the so-called NBZ ("northward Bz") field-aligned current system.

A Novel Prediction Method about Single Components of Analog Circuits Based on Complex Field Modeling

PubMed Central

Tian, Shulin; Yang, Chenglin

2014-01-01

Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments. PMID:25147853

Multifunctional Self-Adhesive Fibrous Layered Matrix (FiLM) for Tissue Glues and Therapeutic Carriers.

PubMed

Yoon, Ye-Eun; Im, Byung Gee; Kim, Jung-Suk; Jang, Jae-Hyung

2017-01-09

Tissue adhesives, which inherently serve as wound sealants or as hemostatic agents, can be further augmented to acquire crucial functions as scaffolds, thereby accelerating wound healing or elevating the efficacy of tissue regeneration. Herein, multifunctional adherent fibrous matrices, acting as self-adhesive scaffolds capable of cell/gene delivery, were devised by coaxially electrospinning poly(caprolactone) (PCL) and poly(vinylpyrrolidone) (PVP). Wrapping the building block PCL fibers with the adherent PVP layers formed film-like fibrous matrices that could rapidly adhere to wet biological surfaces, referred to as fibrous layered matrix (FiLM) adhesives. The inclusion of ionic salts (i.e., dopamine hydrochloride) in the sheath layers generated spontaneously multilayered fibrous adhesives, whose partial layers could be manually peeled off, termed derivative FiLM (d-FiLM). In the context of scaffolds/tissue adhesives, both FiLM and d-FiLM demonstrated almost identical characteristics (i.e., sticky, mechanical, and performances as cell/gene carriers). Importantly, the single FiLM-process can yield multiple sets of d-FiLM by investing the same processing time, materials, and labor required to form a single conventional adhesive fibrous mat, thereby highlighting the economic aspects of the process. The FiLM/d-FiLM offer highly impacting contributions to many biomedical applications, especially in fields that require urgent aids (e.g., endoscopic surgeries, implantation in wet environments, severe wounds).

Chemical Ionization Mass Spectrometry.

DTIC Science & Technology

1980-01-30

8217 ’ b o t5D&(( Irff irent from Controlling Office) IS. SECURITY CLASS. (of this report) 1< ; ~ / 1-j~. Unclassified 1S. DECLASSI FI CATION/DOWNGRADING...level in industrial sludge without any prior chromatogaphic or wet chemical separation of this comolex matrix. D. F. Hunt, J. Shabanowitz, and A. B ...Analytical Cheristry, April 1979 12)D. F. Hunt , J. Shabanowitz, and A. B . Giordani, Collision Activated Decompositions or Megative Ions in a Triple Quadrupole

Suzaku Observations of Near-Relativistic Outflows in the BAL Quasar APM 08279+5255

NASA Astrophysics Data System (ADS)

Saez, C.; Chartas, G.; Brandt, W. N.

2009-05-01

We present results from three Suzaku observations of the z = 3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of lsim2 keV (low energy) and 7-12 keV (high energy). The detection of these features confirms the results of previous long-exposure (80-90 ks) Chandra and XMM-Newton observations. The low- and high-energy absorption is detected in both the back-illuminated (BI) and front-illuminated (FI) Suzaku X-ray Imaging Spectrometer spectra (with an F-test significance of gsim99%). We interpret the low-energy absorption as arising from a low-ionization absorber with log N H ~ 23 and the high-energy absorption as due to lines arising from highly ionized (2.75 lsim logξ lsim 4.0, where ξ is the ionization parameter) iron in a near-relativistic outflowing wind. Assuming this interpretation we find that the velocities in the outflow range between 0.1c and 0.6c. We constrain the angle between the outflow direction of the X-ray absorber and our line of sight to be lsim36°. We also detect likely variability of the absorption lines (at the gsim99.9% and gsim98% significance levels in the FI and BI spectra, respectively) with a rest-frame timescale of ~1 month. Assuming that the detected high-energy absorption features arise from Fe XXV, we estimate that the fraction of the total bolometric energy injected over the quasar's lifetime into the intergalactic medium in the form of kinetic energy to be gsim10%.

Flow Injection Mass Spectral Fingerprints Demonstrate Chemical Differences in Rio Red Grapefruit with Respect to Year, Harvest Time, and Conventional versus Organic Farming

PubMed Central

Chen, Pei; Harnly, James M.; Lester, Gene E.

2013-01-01

Spectral fingerprints were acquired for Rio Red grapefruit using flow injection electrospray ionization with ion trap and time-of-flight mass spectrometry (FI-ESI-IT-MS and FI-ESI-TOF-MS). Rio Red grapefruits were harvested 3 times a year (early, mid, and late harvests) in 2005 and 2006 from conventionally and organically grown trees. Data analysis using analysis of variance principal component analysis (ANOVA-PCA) demonstrated that, for both MS systems, the chemical patterns were different as a function of farming mode (conventional vs organic), as well as growing year and time of harvest. This was visually obvious with PCA and was shown to be statistically significant using ANOVA. The spectral fingerprints provided a more inclusive view of the chemical composition of the grapefruit and extended previous conclusions regarding the chemical differences between conventionally and organically grown Rio Red grapefruit. PMID:20337420

Field Independence: Reviewing the Evidence

ERIC Educational Resources Information Center

Evans, Carol; Richardson, John T. E.; Waring, Michael

2013-01-01

Background: The construct of ?eld independence (FI) remains one of the most widely cited notions in research on cognitive style and on learning and instruction more generally. However, a great deal of confusion continues to exist around the de?nition of FI, its measurement, and the interpretation of research results, all of which have served to…

Effects of furrow irrigation on the growth, production, and water use efficiency of direct sowing rice.

PubMed

He, Chunlin

2010-08-03

Rice farming is the major crop production in Asia and is predicted to increase significantly in the near future in order to meet the demands for the increasing human population. Traditional irrigation methods used in rice farming often result in great water loss. New water-saving methods are urgently needed to reduce water consumption. Three field and pot experiments were conducted to evaluate the furrow irrigation (FI) system to improve water use efficiency (WUE) and production of direct sowing rice in southern China. Compared to the conventional irrigation (CI) system (continuous flooding irrigation), for every square hectometer of rice field, the FI system reduced water use by 3130 m3, or 48.1%, and increased grain production by 13.9% for an early cultivar. For a late cultivar, the FI system reduced water use by 2655 m3, or 40.6%, and an increase of grain production by 12.1%. The improved WUE in the FI system is attributed to (1) a significant reduction of irrigation rate, seepage, evaporation, and evapotranspiration; (2) a significant reduction in the reduced materials, such as ferrous ion (Fe2+), and therefore an increase in the vitality of the root system, evident by the increases in the number of white roots by 32.62%, and decreases in the number of black roots by 20.04% and yellow roots by 12.58%; the use of the FI system may also reduce humidity of the rice field and enhance gas transport in the soil and light penetration, which led to reduced rice diseases and increased leaf vitality; and (3) increases in tiller and effective spikes by 11.53% and the weight per thousand grains by 1.0 g. These findings suggest that the shallow FI system is a promising means for rice farming in areas with increasing water shortages.

Response of Caenorhabditis elegans to wireless devices radiation exposure.

PubMed

Fasseas, Michael K; Fragopoulou, Adamantia F; Manta, Areti K; Skouroliakou, Aikaterini; Vekrellis, Konstantinos; Margaritis, Lukas H; Syntichaki, Popi

2015-03-01

To examine the impact of electromagnetic radiation, produced by GSM (Global System for Mobile communications) mobile phones, Wi-Fi (Wireless-Fidelity) routers and wireless DECT (Digital Enhanced Cordless Telecommunications) phones, on the nematode Caenorhabditis elegans. We exposed synchronized populations, of different developmental stages, to these wireless devices at E-field levels below ICNIRP's (International Commission on Non-Ionizing Radiation Protection) guidelines for various lengths of time. WT (wild-type) and aging- or stress-sensitive mutant worms were examined for changes in growth, fertility, lifespan, chemotaxis, short-term memory, increased ROS (Reactive Oxygen Species) production and apoptosis by using fluorescent marker genes or qRT-PCR (quantitative Reverse Transcription-Polymerase Chain Reaction). No statistically significant differences were found between the exposed and the sham/control animals in any of the experiments concerning lifespan, fertility, growth, memory, ROS, apoptosis or gene expression. The worm appears to be robust to this form of (pulsed) radiation, at least under the exposure conditions used.

Method for Correction of Consequences of Radiation-Induced Heart Disease using Low-Intensity Electromagnetic Emission under Experimental Conditions.

PubMed

Bavrina, A P; Monich, V A; Malinovskaya, S L; Yakovleva, E I; Bugrova, M L; Lazukin, V F

2015-05-01

Effects of successive exposure to ionizing irradiation and low-intensity broadband red light on electrical activity of the heart and myocardium microstructure were studied in rats. Lowintensity red light corrected some ECG parameters, in particular, it normalized QT and QTc intervals and voltage of R and T waves. Changes in ECG parameters were followed by alterations in microstructure of muscle fi laments in the myocardium of treatment group animals comparing to control group.

Turbulence scaling study in an MHD wind tunnel on the Swarthmore Spheromak Experiment

NASA Astrophysics Data System (ADS)

Schaffner, D. A.; Wan, A.; Owusu-Boateng, J.; Brown, M. R.; Lukin, V. S.

2013-10-01

The turbulence of colliding spheromaks are explored in the MHD wind tunnel on the SSX. Fully ionized hydrogen plasma is produced by two plasma guns on opposite sides of a 1 m by 15 cm copper cylinder. Modification of B-field, Ti and β are made through stuffing flux variation of the plasma guns. Presented here are turbulent f-/ k-spectra and correlation times/lengths of B-field fluctuations as measured by a 16 channel B-dot radial probe array at the chamber midplane. Power-law fits to spectra show scaling that is robust to changes in stuffing flux; fits are on the order of f-3 and k - 2 . 1 for all flux variations. Dissipation range modification of the spectra is observed; changes to the f-spectra slopes occur around f =fci while changes in k-spectra slopes appear around ~ 5ρi . Dissipation range fits are made with an exponentially modified power-law model [Terry et al., PoP 2012]. Fluctuations in axial velocity are made using a Mach probe. Both B-field and velocity fluctuations persist on the same timescale in these experiments. Mach velocity f-spectra show power-laws similar to that for B-field. Comparison of spectra from MHD and Hall MHD simulations of SSX performed within the HiFi modeling framework are made to the experimental results.

The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Catrin F., E-mail: williamscf@cardiff.ac.uk; School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales; Geroni, Gilles M.

Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separatedmore » electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.« less

The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

NASA Astrophysics Data System (ADS)

Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lloyd, David; Lees, Jonathan; Porch, Adrian

2016-08-01

Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the "internet of things" is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

Statistical study of free magnetic energy and flare productivity of solar active regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, J. T.; Jing, J.; Wang, S.

Photospheric vector magnetograms from the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both nonlinear force-free and potential magnetic fields in solar corona. Based on the extrapolations, we are able to determine the free magnetic energy (FME) stored in active regions (ARs). Over 3000 vector magnetograms in 61 ARs were analyzed. We compare FME with the ARs' flare index (FI) and find that there is a weak correlation (<60%) between FME and FI. FME shows slightly improved flare predictability relative to the total unsigned magnetic flux of ARs in themore » following two aspects: (1) the flare productivity predicted by FME is higher than that predicted by magnetic flux and (2) the correlation between FI and FME is higher than that between FI and magnetic flux. However, this improvement is not significant enough to make a substantial difference in time-accumulated FI, rather than individual flare, predictions.« less

The Development of the DSM-5 Cultural Formulation Interview-Fidelity Instrument (CFI-FI): A Pilot Study

PubMed Central

Aggarwal, Neil Krishan; Glass, Andrew; Tirado, Amilcar; Boiler, Marit; Nicasio, Andel; Alegría, Margarita; Wall, Melanie; Lewis-Fernández, Roberto

2015-01-01

This paper reports on the development of the Cultural Formulation Interview-Fidelity Instrument (CFI-FI) which assesses clinician fidelity to the DSM-5 Cultural Formulation Interview (CFI). The CFI consists of a manualized set of standard questions that can precede every psychiatric evaluation. It is based on the DSM-IV Outline for Cultural Formulation, the cross-cultural assessment with the most evidence in psychiatric training. Using the New York sample of the DSM-5 CFI field trial, two independent raters created and finalized items for the CFI-FI based on six audio-taped and transcribed interviews. The raters then used the final CFI-FI to rate the remaining 23 interviews. Inter-rater reliability ranged from .73 to 1 for adherence items and .52 to 1 for competence items. The development of the CFI-FI can help researchers and administrators determine whether the CFI has been implemented with fidelity, permitting future intervention research. PMID:25130248

Investigation of novel inverted NiO@NixCo1-xO core-shell nanoparticles

NASA Astrophysics Data System (ADS)

Hasan, Samiul; Mayanovic, R. A.; Benamara, Mourad

2018-05-01

Inverse core-shell nanoparticles, comprised of an antiferromagnetic (AFM) core covered by a ferromagnetic (FM) or ferrimagnetic (FiM) shell, are of current interest due to their different potential application and due to the tunability of their magnetic properties. The antiferromagnetic nature of NiO and high Néel temperature (523 K) makes this material well suited for inverse core-shell nanoparticle applications. Our primary objective in this project has been to synthesize and characterize inverted core-shell nanoparticles (CSNs) comprised of a NiO (AFM) core and a shell consisting of a NixCo1-xO (FiM) compound. The synthesis of the CSNs was made using a two-step process. The NiO nanoparticles were synthesized using a chemical reaction method. Subsequently, the NiO nanoparticles were used to grow the NiO@NixCo1-xO CSNs using our hydrothermal nano-phase epitaxy method. XRD structural characterization shows that the NiO@NixCo1-xO CSNs have the rock salt cubic crystal structure. SEM-EDS data indicates the presence of Co in the CSNs. Magnetic measurements show that the CSNs exhibit AFM/FiM characteristics with a small coercivity field of 30 Oe at 5 K. The field cooled vs zero field cooled hysteresis loop measurements show a magnetization axis shift which is attributed to the exchange bias effect between the AFM NiO core and an FiM NixCo1-xO shell of the CSNs. Our ab initio based calculations of the NixCo1-xO rock salt structure confirm a weak FiM character and a charge transfer insulator property of the compound.

Gravity Wave Dynamics in a Mesospheric Inversion Layer: 2. Instabilities, Turbulence, Fluxes, and Mixing

NASA Astrophysics Data System (ADS)

Fritts, David C.; Wang, Ling; Laughman, Brian; Lund, Thomas S.; Collins, Richard L.

2018-01-01

A companion paper by Fritts, Laughman, et al. (2017) employed an anelastic numerical model to explore the dynamics of gravity waves (GWs) encountering a mesospheric inversion layer (MIL) having a moderate static stability enhancement and a layer of weaker static stability above. That study revealed that MIL responses, including GW transmission, reflection, and instabilities, are sensitive functions of GW parameters. This paper expands on two of the Fritts, Laughman, et al. (2017) simulations to examine GW instability dynamics and turbulence in the MIL; forcing of the mean wind and stability environments by GW, instability, and turbulence fluxes; and associated heat and momentum transports. These direct numerical simulations resolve turbulence inertial-range scales and yield the following results: GW breaking and turbulence in the MIL occur below where they would otherwise, due to enhancements of GW amplitudes and shears in the MIL. 2-D GW and instability heat and momentum fluxes are 20-30 times larger than 3-D instability and turbulence fluxes. Mean fields are driven largely by 2-D GW and instability dynamics rather than 3-D instabilities and turbulence. 2-D and 3-D heat fluxes in regions of strong turbulence yield small departures from initial T(z) and N2(z) profiles, hence do not yield nearly adiabatic "mixed" layers. Our MIL results are consistent with the relation between the turbulent vertical velocity variance and energy dissipation rate proposed by Weinstock (1981) for the limited intervals evaluated.

Integrating solar energy and climate research into science education

NASA Astrophysics Data System (ADS)

Betts, Alan K.; Hamilton, James; Ligon, Sam; Mahar, Ann Marie

2016-01-01

This paper analyzes multi-year records of solar flux and climate data from two solar power sites in Vermont. We show the inter-annual differences of temperature, wind, panel solar flux, electrical power production, and cloud cover. Power production has a linear relation to a dimensionless measure of the transmission of sunlight through the cloud field. The difference between panel and air temperatures reaches 24°C with high solar flux and low wind speed. High panel temperatures that occur in summer with low wind speeds and clear skies can reduce power production by as much as 13%. The intercomparison of two sites 63 km apart shows that while temperature is highly correlated on daily (R2=0.98) and hourly (R2=0.94) timescales, the correlation of panel solar flux drops markedly from daily (R2=0.86) to hourly (R2=0.63) timescales. Minimum temperatures change little with cloud cover, but the diurnal temperature range shows a nearly linear increase with falling cloud cover to 16°C under nearly clear skies, similar to results from the Canadian Prairies. The availability of these new solar and climate datasets allows local student groups, a Rutland High School team here, to explore the coupled relationships between climate, clouds, and renewable power production. As our society makes major changes in our energy infrastructure in response to climate change, it is important that we accelerate the technical education of high school students using real-world data.

Suzaku Observations Of Near-relativistic Outflows In The Bal Quasar APM 08279+5255.

NASA Astrophysics Data System (ADS)

Saez, Cristian; Chartas, G.; Brandt, N.

2009-12-01

We present results from three Suzaku observations of the z =3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of <2 keV (low-energy) and 7-12 keV (high-energy). The detection of these features confirms the results of previous long-exposure (80-90 ks) Chandra and XMM-Newton observations. The low and high-energy absorption is detected in both the back-illuminated (BI) and front-illuminated (FI) Suzaku XIS spectra (with an F-test significance of <99%). We interpret the low-energy absorption as arising from a low ionization absorber with logNH 23 and the high-energy absorption as due to lines arising from highly ionized iron in a near-relativistic outflowing wind. Assuming this interpretation we find that the velocities in the outflow range between 0.1c and 0.6c. We constrain the angle between the outflow direction of the X-ray absorber and our line of sight to be <36 degrees. We also detect possible variability of the absorption lines (at the <99.9% and <98% significance levels in the FI and BI spectra, respectively) with a rest-frame time scale of 1 month. Assuming that the detected high-energy absorption features arise from FeXXV, we estimate that the fraction of the total bolometric energy injected over the quasar's lifetime into the intergalactic medium in the form of kinetic energy to be >10%.

Patterns in stream greenhouse gas dynamics from mountains to plains in northcentral Wyoming

NASA Astrophysics Data System (ADS)

Kuhn, C.; Bettigole, C.; Glick, H. B.; Seegmiller, L.; Oliver, C. D.; Raymond, P.

2017-09-01

Quantification of small stream contributions to global carbon cycling is key to understanding how freshwater systems transmit and transform carbon between terrestrial and atmospheric pools. To date, greenhouse gas emissions of carbon dioxide and methane from freshwaters, particularly in mountainous regions, remain poorly characterized due to a lack of direct field observations. Using a unique longitudinal approach, we conducted field surveys across two ecoregions (Middle Rockies and Great Plains) in the Clear Creek watershed, a subwatershed of Wyoming's Powder River Basin. We took direct measurements of stream gases using headspace sampling at 30 sites (8 June to 23 October). We observed the lowest and most variable concentrations in headwaters, which flow through a federally designated alpine wilderness area. By contrast, the Great Plains exhibited 1.45 and 4 times higher pCO2 and pCH4 concentrations and the relative contributions of methane increased downstream. Fluxes during snowmelt were 45% and 58% higher for CO2 and CH4 than during base flow but overall were lower than estimates for other systems. Variability for pCO2 was highest during late summer and in the uppermost sections of the headwaters. The high heterogeneity and common undersaturation observed through space and time, especially in the mountains, suggest that downscaled regional estimates may fail to capture variability in fluxes observed at these smaller scales. Based on these results, we strongly recommend higher resolution time series studies and increased scrutiny of systems at near equilibrium, inclusive of winter storage and ice-off events, to improve our understanding of the effects of seasonal dynamics on these processes.

Coexistence of WiFi and WiMAX systems based on PS-request protocols.

PubMed

Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

2011-01-01

We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol.

Pore Pressure Pulse Drove the 2012 Emilia (Italy) Series of Earthquakes

NASA Astrophysics Data System (ADS)

Pezzo, Giuseppe; De Gori, Pasquale; Lucente, Francesco Pio; Chiarabba, Claudio

2018-01-01

The 2012 Emilia earthquakes sequence is the first debated case in Italy of destructive event possibly induced by anthropic activity. During this sequence, two main earthquakes occurred separated by 9 days on contiguous thrust faults. Scientific commissions engaged by the Italian government reported complementary scenarios on the potential trigger mechanism ascribable to exploitation of a nearby oil field. In this study, we combine a refined geodetic source model constrained by precise aftershock locations and an improved tomographic model of the area to define the geometrical relation between the activated faults and investigate possible triggering mechanisms. An aftershock decay rate that deviates from the classical Omori-like pattern and Vp/Vs changes along the fault system suggests that natural pore pressure pulse drove the space-time evolution of seismicity and the activation of the second main shock.

Coexistence of WiFi and WiMAX Systems Based on PS-Request Protocols†

PubMed Central

Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

2011-01-01

We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol. PMID:22163721

Field Trial Data Analysis and Testing (FiTAT) Tool

DTIC Science & Technology

2011-10-01

amplitude/phase pour chaque antenne du réseau) contenu dans les données acquises pourrait être faite par FiTAT et utilisé dans PAASoM pour déterminer...identity matrix, k is the loop gain, φ is the correlation matrix of the incident signals and T = [1 0 . . . 0]T . The length of vector T is equal to the

Quantum control via a genetic algorithm of the field ionization pathway of a Rydberg electron

NASA Astrophysics Data System (ADS)

Gregoric, Vincent C.; Kang, Xinyue; Liu, Zhimin Cheryl; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.

2017-08-01

Quantum control of the pathway along which a Rydberg electron field ionizes is experimentally and computationally demonstrated. Selective field ionization is typically done with a slowly rising electric field pulse. The (1/n*)4 scaling of the classical ionization threshold leads to a rough mapping between arrival time of the electron signal and principal quantum number of the Rydberg electron. This is complicated by the many avoided level crossings that the electron must traverse on the way to ionization, which in general leads to broadening of the time-resolved field ionization signal. In order to control the ionization pathway, thus directing the signal to the desired arrival time, a perturbing electric field produced by an arbitrary wave-form generator is added to a slowly rising electric field. A genetic algorithm evolves the perturbing field in an effort to achieve the target time-resolved field ionization signal.

Impurity and Defect Interactions in GaAs.

DTIC Science & Technology

1984-02-29

3 VPE a X X ASW 3 vIE 33 34 35 36"M-cVO Wawwmba (CM - Z TS 32 -~ - .35T 2II i I MS . 34 35 3 , b Wovor%~~e (€cm -) X3 FiS.l Characteristic donor peaks ...2). Far infrared photoconductivity measurements on Si doped GaAs grown by molecular beam epitaxy (MBE) indicated that the impurity peak previously...difference is donor species dependent, each hydrogenic transition in a photothermal ionization spectrum contains several closely spaced peaks . Each peak cor

A floor-map-aided WiFi/pseudo-odometry integration algorithm for an indoor positioning system.

PubMed

Wang, Jian; Hu, Andong; Liu, Chunyan; Li, Xin

2015-03-24

This paper proposes a scheme for indoor positioning by fusing floor map, WiFi and smartphone sensor data to provide meter-level positioning without additional infrastructure. A topology-constrained K nearest neighbor (KNN) algorithm based on a floor map layout provides the coordinates required to integrate WiFi data with pseudo-odometry (P-O) measurements simulated using a pedestrian dead reckoning (PDR) approach. One method of further improving the positioning accuracy is to use a more effective multi-threshold step detection algorithm, as proposed by the authors. The "go and back" phenomenon caused by incorrect matching of the reference points (RPs) of a WiFi algorithm is eliminated using an adaptive fading-factor-based extended Kalman filter (EKF), taking WiFi positioning coordinates, P-O measurements and fused heading angles as observations. The "cross-wall" problem is solved based on the development of a floor-map-aided particle filter algorithm by weighting the particles, thereby also eliminating the gross-error effects originating from WiFi or P-O measurements. The performance observed in a field experiment performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building on the China University of Mining and Technology (CUMT) campus confirms that the proposed scheme can reliably achieve meter-level positioning.

Radiofrequency exposure from wireless LANs utilizing Wi-Fi technology.

PubMed

Foster, Kenneth R

2007-03-01

This survey measured radiofrequency (RF) fields from wireless local area networks (WLANs) using Wi-Fi technology against a background of RF fields in the environment over the frequency range 75 MHz-3 GHz. A total of 356 measurements were conducted at 55 sites (including private residences, commercial spaces, health care and educational institutions, and other public spaces) in four countries (U.S., France, Germany, Sweden). Measurements were conducted under conditions that would result in the higher end of exposures from such systems. Where possible, measurements were conducted in public spaces as close as practical to the Wi-Fi access points. Additional measurements were conducted at a distance of approximately 1 m from a laptop while it was uploading and downloading large files to the WLAN. This distance was chosen to allow a useful comparison of fields in the far-field of the antenna in the laptop, and give a representative measure of the exposure that a bystander might receive from the laptop. The exposure to the user, particularly if the antenna of the client card were placed against his or her body, would require different measurement techniques beyond the scope of this study. In all cases, the measured Wi-Fi signal levels were very far below international exposure limits (IEEE C95.1-2005 and ICNIRP) and in nearly all cases far below other RF signals in the same environments. An discusses technical aspects of the IEEE 802.11 standard on which WLANs operate that are relevant to determining the levels of RF energy exposure from WLANs. Important limiting factors are the low operating power of client cards and access points, and the low duty cycle of transmission that normally characterizes their operation.

The Quasi-monochromatic ULF Wave Boundary in the Venusian Foreshock: Venus Express Observations

NASA Astrophysics Data System (ADS)

Shan, Lican; Mazelle, Christian; Meziane, Karim; Romanelli, Norberto; Ge, Yasong S.; Du, Aimin; Lu, Quanming; Zhang, Tielong

2018-01-01

The location of ultralow-frequency (ULF) quasi-monochromatic wave onset upstream of Venus bow shock is explored using Venus Express magnetic field data. We report the existence of a spatial foreshock boundary behind which ULF waves are present. We have found that the ULF wave boundary at Venus is sensitive to the interplanetary magnetic field (IMF) direction like the terrestrial one and appears well defined for a cone angle larger than 30°. In the Venusian foreshock, the inclination angle of the wave boundary with respect to the Sun-Venus direction increases with the IMF cone angle. We also found that for the IMF nominal direction (θBX = 36°) at Venus' orbit, the value of this inclination angle is 70°. Moreover, we have found that the inferred velocity of an ion traveling along the ULF boundary is in a qualitative agreement with a quasi-adiabatic reflection of a portion of the solar wind at the bow shock. For an IMF nominal direction at Venus, the inferred bulk speed of ions traveling along this boundary is 1.07 VSW, sufficiently enough to overcome the solar wind convection. This strongly suggests that the backstreaming ions upstream of the Venusian bow shock provide the main energy source for the ULF waves.

The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source

NASA Astrophysics Data System (ADS)

Yokoyama, K.; Lord, J. S.; Murahari, P.; Wang, K.; Dunstan, D. J.; Waller, S. P.; McPhail, D. J.; Hillier, A. D.; Henson, J.; Harper, M. R.; Heathcote, P.; Drew, A. J.

2016-12-01

A high power pulsed laser system has been installed on the high magnetic field muon spectrometer (HiFi) at the International Science Information Service pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high magnetic field, which opens new applications of muon spin spectroscopy. In this report we give an overview of the principle of the HiFi laser system and describe the newly developed techniques and devices that enable precisely controlled photoexcitation of samples in the muon instrument. A demonstration experiment illustrates the potential of this unique combination of the photoexcited system and avoided level crossing technique.

The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source.

PubMed

Yokoyama, K; Lord, J S; Murahari, P; Wang, K; Dunstan, D J; Waller, S P; McPhail, D J; Hillier, A D; Henson, J; Harper, M R; Heathcote, P; Drew, A J

2016-12-01

A high power pulsed laser system has been installed on the high magnetic field muon spectrometer (HiFi) at the International Science Information Service pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high magnetic field, which opens new applications of muon spin spectroscopy. In this report we give an overview of the principle of the HiFi laser system and describe the newly developed techniques and devices that enable precisely controlled photoexcitation of samples in the muon instrument. A demonstration experiment illustrates the potential of this unique combination of the photoexcited system and avoided level crossing technique.

Non-contact, non-destructive, quantitative probing of interfacial trap sites for charge carrier transport at semiconductor-insulator boundary

NASA Astrophysics Data System (ADS)

Choi, Wookjin; Miyakai, Tomoyo; Sakurai, Tsuneaki; Saeki, Akinori; Yokoyama, Masaaki; Seki, Shu

2014-07-01

The density of traps at semiconductor-insulator interfaces was successfully estimated using microwave dielectric loss spectroscopy with model thin-film organic field-effect transistors. The non-contact, non-destructive analysis technique is referred to as field-induced time-resolved microwave conductivity (FI-TRMC) at interfaces. Kinetic traces of FI-TRMC transients clearly distinguished the mobile charge carriers at the interfaces from the immobile charges trapped at defects, allowing both the mobility of charge carriers and the number density of trap sites to be determined at the semiconductor-insulator interfaces. The number density of defects at the interface between evaporated pentacene on a poly(methylmethacrylate) insulating layer was determined to be 1012 cm-2, and the hole mobility was up to 6.5 cm2 V-1 s-1 after filling the defects with trapped carriers. The FI-TRMC at interfaces technique has the potential to provide rapid screening for the assessment of interfacial electronic states in a variety of semiconductor devices.

Solubility and leaching risks of organic carbon in paddy soils as affected by irrigation managements.

PubMed

Xu, Junzeng; Yang, Shihong; Peng, Shizhang; Wei, Qi; Gao, Xiaoli

2013-01-01

Influence of nonflooding controlled irrigation (NFI) on solubility and leaching risk of soil organic carbon (SOC) were investigated. Compared with flooding irrigation (FI) paddies, soil water extractable organic carbon (WEOC) and dissolved organic carbon (DOC) in NFI paddies increased in surface soil but decreased in deep soil. The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields. It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation. That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies. Change of solubility of SOC in NFI paddies might lead to potential change in soil fertility and sustainability, greenhouse gas emission, and bioavailability of trace metals or organic pollutants.

Evaluation of electromagnetic interference and exposure assessment from s-health solutions based on Wi-Fi devices.

PubMed

de Miguel-Bilbao, Silvia; Aguirre, Erik; Lopez Iturri, Peio; Azpilicueta, Leire; Roldán, José; Falcone, Francisco; Ramos, Victoria

2015-01-01

In the last decade the number of wireless devices operating at the frequency band of 2.4 GHz has increased in several settings, such as healthcare, occupational, and household. In this work, the emissions from Wi-Fi transceivers applicable to context aware scenarios are analyzed in terms of potential interference and assessment on exposure guideline compliance. Near field measurement results as well as deterministic simulation results on realistic indoor environments are presented, providing insight on the interaction between the Wi-Fi transceiver and implantable/body area network devices as well as other transceivers operating within an indoor environment, exhibiting topological and morphological complexity. By following approaches (near field estimation/deterministic estimation), colocated body situations as well as large indoor emissions can be determined. The results show in general compliance with exposure levels and the impact of overall network deployment, which can be optimized in order to reduce overall interference levels while maximizing system performance.

Evaluation of Electromagnetic Interference and Exposure Assessment from s-Health Solutions Based on Wi-Fi Devices

PubMed Central

de Miguel-Bilbao, Silvia; Aguirre, Erik; Lopez Iturri, Peio; Azpilicueta, Leire; Roldán, José; Falcone, Francisco; Ramos, Victoria

2015-01-01

In the last decade the number of wireless devices operating at the frequency band of 2.4 GHz has increased in several settings, such as healthcare, occupational, and household. In this work, the emissions from Wi-Fi transceivers applicable to context aware scenarios are analyzed in terms of potential interference and assessment on exposure guideline compliance. Near field measurement results as well as deterministic simulation results on realistic indoor environments are presented, providing insight on the interaction between the Wi-Fi transceiver and implantable/body area network devices as well as other transceivers operating within an indoor environment, exhibiting topological and morphological complexity. By following approaches (near field estimation/deterministic estimation), colocated body situations as well as large indoor emissions can be determined. The results show in general compliance with exposure levels and the impact of overall network deployment, which can be optimized in order to reduce overall interference levels while maximizing system performance. PMID:25632400

Effect of in utero wi-fi exposure on the pre- and postnatal development of rats.

PubMed

Poulletier de Gannes, Florence; Haro, Emmanuelle; Hurtier, Annabelle; Taxile, Murielle; Athane, Axel; Ait-Aissa, Saliha; Masuda, Hiroshi; Percherncier, Yann; Ruffié, Gilles; Billaudel, Bernard; Dufour, Philippe; Veyret, Bernard; Lagroye, Isabelle

2012-04-01

The increase in exposure to the Wireless Fidelity (Wi-Fi) wireless communication signal has raised public health concerns especially for young people. Animal studies looking at the effects of early life and prenatal exposure to this source of electromagnetic fields, in the radiofrequency (RF) range, on development and behavior have been considered as high priority research needs by the World Health Organization. For the first time, our study assessed the effects of in utero exposure to a 2450 MHz Wi-Fi signal (2 hr/day, 6 days/week for 18 days) on pregnant rats and their pups. Three levels in terms of whole-body specific absorption rate were used: 0.08, 0.4, and 4 W/kg. The prenatal study on fetuses delivered by caesarean (P20) concerned five females/group. The dams and their offspring were observed for 28 days after delivery (15 females/group). For all test conditions, no abnormalities were noted in the pregnant rats and no significant signs of toxicity were observed in the pre- and postnatal development of the pups, even at the highest level of 4 W/kg. In the present study, no teratogenic effect of repeated exposures to the Wi-Fi wireless communication signal was demonstrated even at the highest level of 4 W/kg. The results from this screening study aimed at investigating Wi-Fi effects, strengthen the previous conclusions that teratology and development studies have not detected any noxious effects of exposures to mobile telephony-related RF fields at exposure levels below standard limits. © 2012 Wiley Periodicals, Inc.

Effects of prenatal exposure to WIFI signal (2.45GHz) on postnatal development and behavior in rat: Influence of maternal restraint.

PubMed

Othman, Haifa; Ammari, Mohamed; Sakly, Mohsen; Abdelmelek, Hafedh

2017-05-30

The present study was carried out to investigate the potential combined influence of maternal restraint stress and 2.45GHz WiFi signal exposure on postnatal development and behavior in the offspring of exposed rats. 24 pregnant albino Wistar rats were randomly assigned to four groups: Control, WiFi-exposed, restrained and both WiFi-exposed and restrained groups. Each of WiFi exposure and restraint occurred 2h/day along gestation till parturition. The pups were evaluated for physical development and neuromotor maturation. Moreover, elevated plus maze test, open field activity and stationary beam test were also determined on postnatal days 28, 30 and 31, respectively. After behavioral tests, the rats were anesthetized and their brains were removed for biochemical analysis. Our main findings showed no detrimental effects on gestation progress and outcomes at delivery in all groups. Subsequently, WiFi and restraint, per se and mainly in concert altered physical development of pups with slight differences between genders. Behaviorally, the gestational WiFi irradiation, restraint and especially the associated treatment affected the neuromotor maturation mainly in male progeny. At adult age, we noticed anxiety, motor deficit and exploratory behavior impairment in male offspring co-exposed to WiFi radiation and restraint, and in female progeny subjected to three treatments. The biochemical investigation showed that, all three treatments produced global oxidative stress in brain of both sexes. As for serum biochemistry, phosphorus, magnesium, glucose, triglycerides and calcium levels were disrupted. Taken together, prenatal WiFi radiation and restraint, alone and combined, provoked several behavioral and biochemical impairments at both juvenile and adult age of the offspring. Copyright © 2017 Elsevier B.V. All rights reserved.

Cooperative Localization on Computationally Constrained Devices

DTIC Science & Technology

2012-03-22

Fi hotspot capability. The HTC phone is equipped with the Qualcomm MSM7200A chipset which includes support for 802.11 b/g, digital compass and...Chipset Specifications Wi-Fi Qualcomm MSM7200A +802.11 b/g Bluetooth Qualcomm MSM7200A -Version 2.0 + EDR Accelerometer Bosh BMA 150 +25-1500Hz...Magnetic Field Compensation GPS Qualcomm MSM7200A +Enhanced filtering software to optimize accuracy +gpsOneXTRA for enhanced standalone

Effect of Microwave Wi-Fi Radiation at Frequency of 2.4 GHz on Epileptic Behavior of Rats.

PubMed

A, Mahmoudi; M B, Shojaeifard; S, Nematollahii; S M J, Mortazavi; A R, Mehdizadeh

2018-06-01

Electromagnetic fields (EMF) with different intensities are widely used at home, offices and public places.Today, there is a growing global concern about the effects of human exposure to EMFs. Epilepsy is one of the most common chronic neurological diseases, affecting 50 million people of all ages worldwide. We aimed to investigate the effect of exposure to Wi-Fi radiation on epileptic behavior of rats. 147 male rats, weighing 200-250 g, were divided into seven groups; negative control (no intervention), sham 1(distilled water), positive control (Pentylentetrazol [PTZ]), intervention group 1 (PTZ + Wi-Fi "off"), sham 2 (distilled water + Wi-Fi "off"), sham 3 (distilled water + Wi-Fi "on"), and intervention group 2 (PTZ + Wi-Fi "on"). The rats were exposed to Wi-Fi for 2h at a distance of 30cm from a commercial Wi-Fi router. Convulsive behaviors of rats were monitored and scored based on the intensity and type by measuring latency/threshold time, number of convulsions, sum of scores and durations of seizure, and duration of score 6 seizure. Kruskal-Wallis and Mann-Whitney U-tests were used to analyze the data. Convulsion was observed in interventions Group 4 and Group 7, and positive control. The mean number of events, and sum of scores were significantly different in intervention 2 than other two groups. However, the differences in mean threshold, mean sum of durations and " time to show convulsion with score 6 " were not statistically significant (P>0.05). Due to limitations of our study including the sample size, these findings should be interpreted with caution. In this study, exposure to 2.4 GHz Wi-Fi radiation showed significant beneficial effects on the epileptic behaviour of rats. More experiments are needed to verify if these exposures can be used as a therapeutic approach for amelioration of seizures in epilepsy.

Effect of Microwave Wi-Fi Radiation at Frequency of 2.4 GHz on Epileptic Behavior of Rats

PubMed Central

A., Mahmoudi; M.B., Shojaeifard; S., Nematollahii; S.M.J., Mortazavi; A.R., Mehdizadeh

2018-01-01

Background: Electromagnetic fields (EMF) with different intensities are widely used at home, offices and public places.Today, there is a growing global concern about the effects of human exposure to EMFs. Epilepsy is one of the most common chronic neurological diseases, affecting 50 million people of all ages worldwide. We aimed to investigate the effect of exposure to Wi-Fi radiation on epileptic behavior of rats. Materials and Methods: 147 male rats, weighing 200-250 g, were divided into seven groups; negative control (no intervention), sham 1(distilled water), positive control (Pentylentetrazol [PTZ]), intervention group 1 (PTZ + Wi-Fi “off”), sham 2 (distilled water + Wi-Fi “off”), sham 3 (distilled water + Wi-Fi “on”), and intervention group 2 (PTZ + Wi-Fi “on”). The rats were exposed to Wi-Fi for 2h at a distance of 30cm from a commercial Wi-Fi router. Convulsive behaviors of rats were monitored and scored based on the intensity and type by measuring latency/threshold time, number of convulsions, sum of scores and durations of seizure, and duration of score 6 seizure. Kruskal-Wallis and Mann-Whitney U-tests were used to analyze the data. Results: Convulsion was observed in interventions Group 4 and Group 7, and positive control. The mean number of events, and sum of scores were significantly different in intervention 2 than other two groups. However, the differences in mean threshold, mean sum of durations and “ time to show convulsion with score 6 ” were not statistically significant (P>0.05). Conclusion: Due to limitations of our study including the sample size, these findings should be interpreted with caution. In this study, exposure to 2.4 GHz Wi-Fi radiation showed significant beneficial effects on the epileptic behaviour of rats. More experiments are needed to verify if these exposures can be used as a therapeutic approach for amelioration of seizures in epilepsy. PMID:29951445

Opposite Latitudinal Dependence of the Premidnight and Postmidnight Oscillations in the Electron Density of Midlatitude F Layer

NASA Astrophysics Data System (ADS)

Chen, Gang; Wang, Jin; Zhang, Shaodong; Deng, Zhongxin; Zhong, Dingkun; Wu, Chen; Jin, Han; Li, Yaxian

2018-01-01

The dense observation points of the oblique-incidence ionosonde network in North China make it possible to discover the ionospheric regional variations with relatively high spatial resolution. The ionosonde network and the Beijing digisonde are used to investigate the ionospheric nighttime oscillations in January and February 2011. The electron density enhancements occurring before and after midnight present the obvious opposite latitudinal dependence in the time-latitude maps, which are composed by the differential critical frequency of F2 layer. The premidnight enhancements (PRMEs) appeared earlier in the north and then moved to south. The postmidnight enhancements (POMEs) did the opposite. The data analysis shows that the PRME was a part of the large-scale traveling ionospheric disturbance (LSTID), which may be produced by gravity waves. The southward propagation of the LSTIDs is considered to form the positive latitudinal dependence of the wave peaks and troughs. The postmidnight F layer oscillation was composed by a single enhancement and a single decline following it. The westward electric field-induced E × B drift, which pushed the F layer to lower altitudes with higher recombination loss, was most likely to compress the plasma and produce the POMEs. Along with the continuously dropping of the layer, the recombination loss exceeded the density increase due to the compression effect and then the electron density decline appeared.

A Floor-Map-Aided WiFi/Pseudo-Odometry Integration Algorithm for an Indoor Positioning System

PubMed Central

Wang, Jian; Hu, Andong; Liu, Chunyan; Li, Xin

2015-01-01

This paper proposes a scheme for indoor positioning by fusing floor map, WiFi and smartphone sensor data to provide meter-level positioning without additional infrastructure. A topology-constrained K nearest neighbor (KNN) algorithm based on a floor map layout provides the coordinates required to integrate WiFi data with pseudo-odometry (P-O) measurements simulated using a pedestrian dead reckoning (PDR) approach. One method of further improving the positioning accuracy is to use a more effective multi-threshold step detection algorithm, as proposed by the authors. The “go and back” phenomenon caused by incorrect matching of the reference points (RPs) of a WiFi algorithm is eliminated using an adaptive fading-factor-based extended Kalman filter (EKF), taking WiFi positioning coordinates, P-O measurements and fused heading angles as observations. The “cross-wall” problem is solved based on the development of a floor-map-aided particle filter algorithm by weighting the particles, thereby also eliminating the gross-error effects originating from WiFi or P-O measurements. The performance observed in a field experiment performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building on the China University of Mining and Technology (CUMT) campus confirms that the proposed scheme can reliably achieve meter-level positioning. PMID:25811224

Potential antianxiety activity of Fumaria indica: A preclinical study

PubMed Central

Singh, Gireesh K.; Chauhan, Sudhir K.; Rai, Geeta; Chatterjee, Shyam S.; Kumar, Vikas

2013-01-01

Background: In the view of diverse CNS modulating properties of Fumaria indica, present study was planned to evaluate its putative anxiolytic activity in behavioural models of rats, followed by elucidation of mechanism of observed activity through biochemical estimations. Materials and Methods: Effects of seven daily 100, 200 and 400 mg/kg oral doses of a Fumaria indica extract (FI) was compared with those of an acute oral dose (5 mg/kg) of lorazepam in a battery of rat models consisting of open-field, elevated plus and zero maze, social interaction, and novelty induced feeding tests. Results: Dose dependant antianxiety effects of FI observed in all tests were qualitatively similar to those of the reference anxiolytic drug. Although FI treatments did not alter the concentrations of noradrenaline and serotonin in hippocampus and hypothalamus, concentrations of both these monoamines were dose dependently elevated in prefrontal cortex of FI treated animals. Flunitrazepam binding in brain frontal cortex was also elevated by the extract. Moreover, higher levels of brain expressions of the cytokines TNF-α, IL-1β, and IL-10 observed in animals with prior experience on elevated plus maze were almost completely reversed by the lowest dose of FI tested in the behavioral models. Conclusion: Taken together, these observations strongly suggest that FI is a functionally novel type of antianxiety agent, and that inhibition of cytokine expressions in the brain could be involved in its mode of action. PMID:23661988

Setting Standards for Reporting and Quantification in Fluorescence-Guided Surgery.

PubMed

Hoogstins, Charlotte; Burggraaf, Jan Jaap; Koller, Marjory; Handgraaf, Henricus; Boogerd, Leonora; van Dam, Gooitzen; Vahrmeijer, Alexander; Burggraaf, Jacobus

2018-05-29

Intraoperative fluorescence imaging (FI) is a promising technique that could potentially guide oncologic surgeons toward more radical resections and thus improve clinical outcome. Despite the increase in the number of clinical trials, fluorescent agents and imaging systems for intraoperative FI, a standardized approach for imaging system performance assessment and post-acquisition image analysis is currently unavailable. We conducted a systematic, controlled comparison between two commercially available imaging systems using a novel calibration device for FI systems and various fluorescent agents. In addition, we analyzed fluorescence images from previous studies to evaluate signal-to-background ratio (SBR) and determinants of SBR. Using the calibration device, imaging system performance could be quantified and compared, exposing relevant differences in sensitivity. Image analysis demonstrated a profound influence of background noise and the selection of the background on SBR. In this article, we suggest clear approaches for the quantification of imaging system performance assessment and post-acquisition image analysis, attempting to set new standards in the field of FI.

Frit inlet field-flow fractionation techniques for the characterization of polyion complex self-assemblies.

PubMed

Till, Ugo; Gaucher, Mireille; Amouroux, Baptiste; Gineste, Stéphane; Lonetti, Barbara; Marty, Jean-Daniel; Mingotaud, Christophe; Bria, Carmen R M; Williams, S Kim Ratanathanawongs; Violleau, Frédéric; Mingotaud, Anne-Françoise

2017-01-20

Polymer self-assemblies joining oppositely charged chains, known as polyion complexes (PICs), have been formed using poly(ethyleneoxide - b - acrylic acid)/poly(l-lysine), poly(ethyleneoxide-b-acrylic acid)/dendrigraft poly(l-lysine) and poly[(3-acrylamidopropyl) trimethylammonium chloride - b - N - isopropyl acrylamide]/poly(acrylic acid). The self-assemblies have been first characterized in batch by Dynamic Light Scattering. In a second step, their analysis by Flow Field-Flow Fractionation techniques (FlFFF) was examined. They were shown to be very sensitive to shearing, especially during the focus step of the fractionation, and this led to an incompatibility with asymmetrical FlFFF. On the other hand, Frit Inlet FlFFF proved to be very efficient to observe them, either in its symmetrical (FI-FlFFF) or asymmetrical version (FI-AsFlFFF). Conditions of elution were found to optimize the sample recovery in pure water. Spherical self-assemblies were detected, with a size range between 70-400nm depending on the polymers. Compared to batch DLS, FI-AsFlFFF clearly showed the presence of several populations in some cases. The influence of salt on poly(ethyleneoxide-b-acrylic acid) (PEO-PAA) 6000-3000/dendrigraft poly(l-lysine) (DGL 3) was also assessed in parallel in batch DLS and FI-AsFlFFF. Batch DLS revealed a first process of swelling of the self-assembly for low concentrations up to 0.8M followed by the dissociation. FI-AsFlFFF furthermore indicated a possible ejection of DGL3 from the PIC assembly for concentrations as low as 0.2M, which could not be observed in batch DLS. Copyright © 2016 Elsevier B.V. All rights reserved.

Linear electric field time-of-flight ion mass spectrometer

DOEpatents

Funsten, Herbert O [Los Alamos, NM; Feldman, William C [Los Alamos, NM

2008-06-10

A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

Double-frequency microwave ionization of Na

NASA Astrophysics Data System (ADS)

Ruff, G. A.; Dietrick, K. M.; Gallagher, T. F.

1990-11-01

We report the ionization of Na atoms by the simultaneous application of microwave fields of two different frequencies. We conclude that the salient features of double-frequency ionization can be readily understood. Both the hydrogenlike ||m||=2 states and the nonhydrogenic ||m||=0 and 1 states ionize when the sum of the field amplitudes, the peak field, reaches the field required for ionization by a single microwave frequency, E=1/9n4 and E=1/3n5, respectively.

Elasticity of Orthoenstatite at High Pressure and Temperature: Implications for the Origin of Low VP/VS Zones in the Mantle Wedge

NASA Astrophysics Data System (ADS)

Qian, Wangsheng; Wang, Wenzhong; Zou, Fan; Wu, Zhongqing

2018-01-01

Orthopyroxene (opx) is an important mineral in petrologic models for the upper mantle. Its elastic properties are fundamental for understanding the chemical composition and geodynamics of the upper mantle. Here we calculate the elastic properties of orthoenstatite (MgSiO3), the Mg end-member orthopyroxene under upper mantle pressure and temperature conditions using first principle calculations with local density approximation. Bulk and shear moduli increase nonlinearly with pressure at mantle temperatures, but the shear modulus and VS show very weak pressure dependence in comparison with VP. Compared to other major minerals in the upper mantle, orthoenstatite has the lowest compressional velocities (VP), shear velocities (VS), and VP/VS ratio down to the depth of approximately 300 km. The enrichment of opx in the upper mantle can cause the unusually low VP/VS observed in the mantle wedge.

Sensitivity of Homogeneous Ice Nucleation to Aerosol Perturbations and Its Implications for Aerosol Indirect Effects Through Cirrus Clouds

NASA Astrophysics Data System (ADS)

Liu, X.; Shi, X.

2018-02-01

The magnitude and sign of anthropogenic aerosol impacts on cirrus clouds through ice nucleation are still very uncertain. In this study, aerosol sensitivity (ηα), defined as the sensitivity of the number concentration (Ni) of ice crystals formed from homogeneous ice nucleation to aerosol number concentration (Na), is examined based on simulations from a cloud parcel model. The model represents the fundamental process of ice crystal formation that results from homogeneous nucleation. We find that the geometric dispersion (σ) of the aerosol size distribution used in the model is a key factor for ηα. For a monodisperse size distribution, ηα is close to zero in vertical updrafts (V < 50 cm s-1) typical of cirrus clouds. However, ηα increases to 0.1-0.3 (i.e., Ni increases by a factor of 1.3-2.0 for a tenfold increase in Na) if aerosol particles follow lognormal size distributions with a σ of 1.6-2.3 in the upper troposphere. By varying the input aerosol and environmental parameters, our model reproduces a large range of ηα values derived from homogeneous ice nucleation parameterizations widely used in global climate models (GCMs). The differences in ηα from these parameterizations can translate into a range of anthropogenic aerosol longwave indirect forcings through cirrus clouds from 0.05 to 0.36 W m-2 with a GCM. Our study suggests that a larger ηα (0.1-0.3) is more plausible and the homogeneous nucleation parameterizations should include a realistic aerosol size distribution to accurately quantify anthropogenic aerosol indirect effects.

SAR in a child voxel phantom from exposure to wireless computer networks (Wi-Fi).

PubMed

Findlay, R P; Dimbylow, P J

2010-08-07

Specific energy absorption rate (SAR) values have been calculated in a 10 year old sitting voxel model from exposure to electromagnetic fields at 2.4 and 5 GHz, frequencies commonly used by Wi-Fi devices. Both plane-wave exposure of the model and irradiation from antennas in the near field were investigated for a variety of exposure conditions. In all situations studied, the SAR values calculated were considerably below basic restrictions. For a typical Wi-Fi exposure scenario using an inverted F antenna operating at 100 mW, a duty factor of 0.1 and an antenna-body separation of 34 cm, the maximum peak localized SAR was found to be 3.99 mW kg(-1) in the torso region. At 2.4 GHz, using a power of 100 mW and a duty factor of 1, the highest localized SAR value in the head was calculated as 5.7 mW kg(-1). This represents less than 1% of the SAR previously calculated in the head for a typical mobile phone exposure condition.

Non-contact, non-destructive, quantitative probing of interfacial trap sites for charge carrier transport at semiconductor-insulator boundary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Wookjin; Miyakai, Tomoyo; Sakurai, Tsuneaki

The density of traps at semiconductor–insulator interfaces was successfully estimated using microwave dielectric loss spectroscopy with model thin-film organic field-effect transistors. The non-contact, non-destructive analysis technique is referred to as field-induced time-resolved microwave conductivity (FI-TRMC) at interfaces. Kinetic traces of FI-TRMC transients clearly distinguished the mobile charge carriers at the interfaces from the immobile charges trapped at defects, allowing both the mobility of charge carriers and the number density of trap sites to be determined at the semiconductor-insulator interfaces. The number density of defects at the interface between evaporated pentacene on a poly(methylmethacrylate) insulating layer was determined to be 10{supmore » 12 }cm{sup −2}, and the hole mobility was up to 6.5 cm{sup 2} V{sup −1} s{sup −1} after filling the defects with trapped carriers. The FI-TRMC at interfaces technique has the potential to provide rapid screening for the assessment of interfacial electronic states in a variety of semiconductor devices.« less

Regime-Dependent Differences in Surface Freshwater Exchange Estimates Over the Ocean

NASA Astrophysics Data System (ADS)

Wong, Sun; Behrangi, Ali

2018-01-01

Differences in gridded precipitation (P), surface evaporation (E), and the resultant surface freshwater exchange (P - E) among different products over the ocean are diagnosed as functions of moisture advection (Qadvt) and moisture tendency by dynamical convergence (Qcnvg). Compared to the GPCP product, the TRMM3B42 product captures higher frequency of precipitation with larger extreme precipitation rates in regimes of deep convection and more light rain detections in regimes of frequent occurrence of boundary layer clouds. Discrepancies in E depend on moisture flux divergence, with the OAFlux product having the largest E in regimes of divergence. Discrepancies in mean P - E in deep convective regimes are highly influenced by differences in precipitation, with the TRMM3B42 product yielding P - E histograms closer to those inferred from the reanalysis moisture flux convergence. In nonconvergent regimes, observation-based P - E histograms skew toward positive values while the inferred reanalysis histograms are symmetric about the means.

Recasts, Field Dependence/Independence Cognitive Style, and L2 Development

ERIC Educational Resources Information Center

Rassaei, Ehsan

2015-01-01

While previous research has indicated that learners with field-dependence (FD) and field-independence (FI) cognitive styles benefit differentially from different instructional modes, previous corrective feedback studies have ignored the issue of matching error correction strategies to learners' cognitive style. To shed some light on this issue,…

Investigation of the effects of distance from sources on apoptosis, oxidative stress and cytosolic calcium accumulation via TRPV1 channels induced by mobile phones and Wi-Fi in breast cancer cells.

PubMed

Çiğ, Bilal; Nazıroğlu, Mustafa

2015-10-01

TRPV1 is a Ca2+ permeable channel and gated by noxious heat, oxidative stress and capsaicin (CAP). Some reports have indicated that non-ionized electromagnetic radiation (EMR)-induces heat and oxidative stress effects. We aimed to investigate the effects of distance from sources on calcium signaling, cytosolic ROS production, cell viability, apoptosis, plus caspase-3 and -9 values induced by mobile phones and Wi-Fi in breast cancer cells MCF-7 human breast cancer cell lines were divided into A, B, C and D groups as control, 900, 1800 and 2450 MHz groups, respectively. Cells in Group A were used as control and were kept in cell culture conditions without EMR exposure. Groups B, C and D were exposed to the EMR frequencies at different distances (0 cm, 1 cm, 5 cm, 10 cm, 20 cm and 25 cm) for 1h before CAP stimulation. The cytosolic ROS production, Ca2+ concentrations, apoptosis, caspase-3 and caspase-9 values were higher in groups B, C and D than in A group at 0 cm, 1 cm and 5 cm distances although cell viability (MTT) values were increased by the distances. There was no statistically significant difference in the values between control, 20 and 25 cm. Wi-Fi and mobile phone EMR placed within 10 cm of the cells induced excessive oxidative responses and apoptosis via TRPV1-induced cytosolic Ca2+ accumulation in the cancer cells. Using cell phones and Wi-Fi sources which are farther away than 10 cm may provide useful protection against oxidative stress, apoptosis and overload of intracellular Ca2+. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. Copyright © 2015 Elsevier B.V. All rights reserved.

Who Decides: Me or We? Family Involvement in Medical Decision Making in Eastern and Western Countries.

PubMed

Alden, Dana L; Friend, John; Lee, Ping Yein; Lee, Yew Kong; Trevena, Lyndal; Ng, Chirk Jenn; Kiatpongsan, Sorapop; Lim Abdullah, Khatijah; Tanaka, Miho; Limpongsanurak, Supanida

2018-01-01

Research suggests that desired family involvement (FI) in medical decision making may depend on cultural values. Unfortunately, the field lacks cross-cultural studies that test this assumption. As a result, providers may be guided by incomplete information or cultural biases rather than patient preferences. Researchers developed 6 culturally relevant disease scenarios varying from low to high medical seriousness. Quota samples of approximately 290 middle-aged urban residents in Australia, China, Malaysia, India, South Korea, Thailand, and the USA completed an online survey that examined desired levels of FI and identified individual difference predictors in each country. All reliability coefficients were acceptable. Regression models met standard assumptions. The strongest finding across all 7 countries was that those who desired higher self-involvement (SI) in medical decision making also wanted lower FI. On the other hand, respondents who valued relational-interdependence tended to want their families involved - a key finding in 5 of 7 countries. In addition, in 4 of 7 countries, respondents who valued social hierarchy desired higher FI. Other antecedents were less consistent. These results suggest that it is important for health providers to avoid East-West cultural stereotypes. There are meaningful numbers of patients in all 7 countries who want to be individually involved and those individuals tend to prefer lower FI. On the other hand, more interdependent patients are likely to want families involved in many of the countries studied. Thus, individual differences within culture appear to be important in predicting whether a patient desires FI. For this reason, avoiding culture-based assumptions about desired FI during medical decision making is central to providing more effective patient centered care.

High pressure xenon ionization detector

DOEpatents

Markey, J.K.

1989-11-14

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

High pressure xenon ionization detector

DOEpatents

Markey, John K.

1989-01-01

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

Using Educational Data Mining Methods to Assess Field-Dependent and Field-Independent Learners' Complex Problem Solving

ERIC Educational Resources Information Center

Angeli, Charoula; Valanides, Nicos

2013-01-01

The present study investigated the problem-solving performance of 101 university students and their interactions with a computer modeling tool in order to solve a complex problem. Based on their performance on the hidden figures test, students were assigned to three groups of field-dependent (FD), field-mixed (FM), and field-independent (FI)…

Interminimum foF1 Differences and Their Physical Interpretation

NASA Astrophysics Data System (ADS)

Mikhailov, A. V.; Perrone, L.

2018-01-01

Interminimum changes of June noontime monthly median foF1 were analyzed for European and Japanese ionosonde stations over the period of five (Moscow six) solar cycles. The magnitude of these changes is different at different stations and depends on the solar minima considered. In particular, both European and Japanese stations manifest a pronounced foF1 change between 1996/1997 and 2008/2009 solar minima, the latter being the deepest one. For the first time, the total EUV solar flux with λ ≤ 1,050 Å has been retrieved for the 1946-2015 period using observed June monthly median foF1. The deep solar minimum in 2008/2009 was the lowest one among the last six solar cycles comparing the retrieved EUV. The change from 1996/1997 to 2008/2009 in the retrieved EUV is 2.0%, and this is much less than the difference of 10-12% being discussed in the literature. A 10% interminimum change in the total EUV flux results in neutral temperature and gas density, which are larger in 2008 than in 1996, and this contradicts the satellite drag neutral gas density observations. The mechanism of foF1 interminimum changes is based on an interplay between molecular (NO+ and O2+) and O+ ions. The main contribution (>72%) to the interminimum NmF1 change provides [M+] ions via the total ion production rate variation, the rest is provided via O+ ions. The absence (or inversed) difference in foF1 between 1996 and 2008 minima implies that neutral temperature and density are larger in 2008 than in 1996, and this contradicts the satellite drag observations.

Experimental optimization of directed field ionization

NASA Astrophysics Data System (ADS)

Liu, Zhimin Cheryl; Gregoric, Vincent C.; Carroll, Thomas J.; Noel, Michael W.

2017-04-01

The state distribution of an ensemble of Rydberg atoms is commonly measured using selective field ionization. The resulting time resolved ionization signal from a single energy eigenstate tends to spread out due to the multiple avoided Stark level crossings atoms must traverse on the way to ionization. The shape of the ionization signal can be modified by adding a perturbation field to the main field ramp. Here, we present experimental results of the manipulation of the ionization signal using a genetic algorithm. We address how both the genetic algorithm and the experimental parameters were adjusted to achieve an optimized result. This work was supported by the National Science Foundation under Grants No. 1607335 and No. 1607377.

Two healing lengths in a two-band GL-model with quadratic terms: Numerical results

NASA Astrophysics Data System (ADS)

Macias-Medri, A. E.; Rodríguez-Núñez, J. J.

2018-05-01

A two-band and quartic interaction order Ginzburg-Landau model in the presence of a single vortex is studied in this work. Interactions of second (quadratic, with coupling parameter γ) and fourth (quartic, with coupling parameter γ˜) order between the two superconducting order parameters (fi with i = 1,2) are incorporated in a functional. Terms beyond quadratic gradient contributions are neglected in the corresponding minimized free energy. The solution of the system of coupled equations is solved by numerical methods to obtain the fi-profiles, where our starting point was the calculation of the superconducting critical temperature Tc. With this at hand, we evaluate fi and the magnetic field along the z-axis, B0, as function of γ, γ˜, the radial distance r/λ1(0) and the temperature T, for T ≈ Tc. The self-consistent equations allow us to compute λ (penetration depth) and the healing lengths of fi (Lhi with i = 1,2) as functions of T, γ and γ˜. At the end, relevant discussions about type-1.5 superconductivity in the compounds we have studied are presented.

Exploring the Links in Monthly to Decadal Variability of the Atmospheric Water Balance Over the Wettest Regions in ERA-20C

NASA Astrophysics Data System (ADS)

Nogueira, M.

2017-10-01

Monthly-to-decadal variability of the regional precipitation over Intertropical Convergence Zone and north-Atlantic and north-Pacific storm tracks was investigated using ERA-20C reanalysis. Satellite-based precipitation (P) and evaporation (E) climatological patterns were well reproduced by ERA-20C. Regional P and E monthly time series displayed 20% differences, but these decreased rapidly with time scale ( 10% at yearly time scales). Spectral analysis showed good scale-by-scale statistical agreement between ERA-20C and observations. Using ERA-Interim showed no improvement despite the much wider range of information assimilated (including satellites). Remarkably high Detrended Cross-Correlation Analysis coefficients (ρDCCA > 0.7 and often ρDCCA > 0.9) revealed tight links between the nonperiodic variability of P, moisture divergence (DIV), and pressure velocity (ω) at monthly-to-decadal time scales over all the wet regions. In contrast, ρDCCA was essentially nonsignificant between nonperiodic P and E or sea surface temperature (SST). Thus, the nonperiodic monthly-to-decadal variability of precipitation in these regions is almost fully controlled by dynamics and not by local E or SST (suggested by Clausius-Clapeyron relation). Analysis of regional nonperiodic standard deviations and power spectra (and respective spectral exponents, β) provided further robustness to this conclusion. Finally, clear transitions in β for P, DIV, and ω between tropical and storm track regions were found. The latter is dominated by transient storms, with energy accumulation at synoptic scales and β < 0.1 at monthly-to-decadal time scales, implying that variability and information creation decrease rapidly with time scale. Larger β values (0.2 to 0.4) were found in the tropics, implying longer-range autocorrelations and slower decreasing variability and information creation with time scale, consistent with the important forcing from internal modes of variability (e.g., El Niño-Southern Oscillation).

Demonstrated Efficient Quasi-Monoenergetic Carbon-Ion Beams Approaching Fast Ignition (FI) Requirements

NASA Astrophysics Data System (ADS)

Fernández, Juan C.; Palaniyappan, S.; Huang, C.; Gautier, D. C.; Santiago, M.

2015-11-01

Using massive computer simulations of relativistic laser-plasma interactions, we have identified a self-organizing scheme that exploits persisting self-generated plasma electric (~TV/m) and magnetic (~104 Tesla) fields to reduce the ion energy spread of intense laser-driven ion beams after the laser exits the plasma. Consistent with the scheme, we have demonstrated on the LANL Trident laser carbon-ion beams with narrow spectral peaks at 220 MeV, with high conversion efficiency (~ 5%). These parameters are within a factor of 2 of FI requirements. The remaining gap may be bridged by increasing the laser intensity by a factor of 4, according to our data. We also discuss how this beam may be focused, to address the remaining requirement for FI, besides the total laser energy. This work is sponsored by the LANL LDRD Program.

The Effects of Field Dependent/Field Independent Cognitive Styles and Motivational Styles on Students' Conceptual Understanding about Direct Current Circuits

ERIC Educational Resources Information Center

Karaçam, Sedat; Digilli Baran, Azize

2015-01-01

The purpose of this study is to investigate the effects of Field Dependent (FD)/Field Independent (FI) cognitive styles and motivational styles on high school students' conceptual understandings about direct current circuit concepts. The participants of this study consisted of 295 high school students (male = 127, female = 168) who were enrolled…

Measurements of Radiofrequency Radiation with a Body-Borne Exposimeter in Swedish Schools with Wi-Fi.

PubMed

Hedendahl, Lena K; Carlberg, Michael; Koppel, Tarmo; Hardell, Lennart

2017-01-01

Wireless access to the Internet is now commonly used in schools. Many schools give each student their own laptop and utilize the laptops and wireless fidelity (Wi-Fi) connection for educational purposes. Most children also bring their own mobile phones to school. Since children are obliged by law to attend school, a safe environment is important. Lately, it has been discussed if radiofrequency (RF) radiation can have long-term adverse effects on children's health. This study conducted exposimetric measurements in schools to assess RF emissions in the classroom by measuring the teachers' RF exposure in order to approximate the children's exposure. Teachers in grades 7-12 carried a body-borne exposimeter, EME-Spy 200, in school during 1-4 days of work. The exposimeter can measure 20 different frequency bands from 87 to 5,850 MHz. Eighteen teachers from seven schools participated. The mean exposure to RF radiation ranged from 1.1 to 66.1 µW/m 2 . The highest mean level, 396.6 µW/m 2 , occurred during 5 min of a lesson when the teacher let the students stream and watch YouTube videos. Maximum peaks went up to 82,857 µW/m 2 from mobile phone uplink. Our measurements are in line with recent exposure studies in schools in other countries. The exposure levels varied between the different Wi-Fi systems, and if the students were allowed to use their own smartphones on the school's Wi-Fi network or if they were connected to GSM/3G/4G base stations outside the school. An access point over the teacher's head gave higher exposure compared with a school with a wired Internet connection for the teacher in the classroom. All values were far below International Commission on Non-Ionizing Radiation Protection's reference values, but most mean levels measured were above the precautionary target level of 3-6 µW/m 2 as proposed by the Bioinitiative Report. The length of time wireless devices are used is an essential determinant in overall exposure. Measures to minimize children's exposure to RF radiation in school would include preferring wired connections, allowing laptops, tablets and mobile phones only in flight mode and deactivating Wi-Fi access points, when not used for learning purposes.

Weakly ionized cosmic gas: Ionization and characterization

NASA Technical Reports Server (NTRS)

Rosenberg, M.; Mendis, D. A.; Chow, V. W.

1994-01-01

Since collective plasma behavior may determine important transport processes (e.g., plasma diffusion across a magnetic field) in certain cosmic environments, it is important to delineate the parameter space in which weakly ionized cosmic gases may be characterized as plasmas. In this short note, we do so. First, we use values for the ionization fraction given in the literature, wherein the ionization is generally assumed to be due primarily to ionization by cosmic rays. We also discuss an additional mechanism for ionization in such environments, namely, the photoelectric emission of electrons from cosmic dust grains in an interstellar Far Ultra Violet (FUV) radiation field. Simple estimates suggest that under certain conditions this mechanism may dominate cosmic ray ionization, and possibly also the photoionization of metal atoms by the interstellar FUV field, and thereby lead to an enhanced ionization level.

Seismic Signature of the Continental Crust: What Thermodynamics Says. An Example From the Italian Peninsula

NASA Astrophysics Data System (ADS)

Diaferia, G.; Cammarano, F.

2017-12-01

Unraveling the temperature distribution and composition of Earth's crust is key for understanding its origin, evolution, and mechanical behavior. Models of compressional (VP) and shear wave (VS) velocity are obtained from seismological studies and can be interpreted in terms of temperature and composition, using relationship defined through laboratory experiments. These empirical evidences often do not properly account for the effects driven by temperature, pressure, water content, and phase change of minerals. In this study, we use thermodynamic modeling to properly investigate the role of these variables in affecting seismic properties, as a tool to guide (joint) inversion and interpretation of geophysical data. We find that mineralogical phase transitions can be more seismically relevant than a change in chemical composition. In particular, the α-β quartz transition would cause a jump in acoustic impedance and VP/VS ratio >8%, occurring in the 15-25 km depth range, depending on the thermal gradient. Moreover, in the case of a cold lower crust, the consumption of plagioclase in favor of high-velocity minerals might represent another relevant seismic discontinuity. Different chemical compositions proposed for the Italian crust would be seismically indistinguishable, since they give overlapping seismic properties. Values of VS < 3.6 km s-1 would imply a strong contribution of sediments and/or partial melt. The VS/density ratio shows a narrow variability, suggesting that densities at depth can be directly derived in first approximation from VS.

Are media reports able to cause somatic symptoms attributed to WiFi radiation? An experimental test of the negative expectation hypothesis.

PubMed

Bräscher, Anne-Kathrin; Raymaekers, Koen; Van den Bergh, Omer; Witthöft, Michael

2017-07-01

People suffering from idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) experience numerous non-specific symptoms that they attribute to EMF. The cause of this condition remains vague and evidence shows that psychological rather than bioelectromagnetic mechanisms are at work. We hypothesized a role of media reports in the etiology of IEI-EMF and investigated how somatosensory perception is affected. 65 healthy participants were instructed that EMF exposure can lead to enhanced somatosensory perception. Participants were randomly assigned to watch either a television report on adverse health effects of EMF or a neutral report. During the following experiment, participants rated stimulus intensities of tactile (electric) stimuli while being exposed to a sham WiFi signal in 50% of the trials. Sham WiFi exposure led to increased intensity ratings of tactile stimuli in the WiFi film group, especially in participants with higher levels of somatosensory amplification. Participants of the WiFi group reported more anxiety concerning WiFi exposure than the Control group and tended to perceive themselves as being more sensitive to EMF after the experiment compared to before. Sensational media reports can facilitate enhanced perception of tactile stimuli in healthy participants. People tending to perceive bodily symptoms as intense, disturbing, and noxious seem most vulnerable. Receiving sensational media reports might sensitize people to develop a nocebo effect and thereby contribute to the development of IEI-EMF. By promoting catastrophizing thoughts and increasing symptom-focused attention, perception might more readily be enhanced and misattributed to EMF. Copyright © 2017 Elsevier Inc. All rights reserved.

Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 GPa and 1073 K

NASA Astrophysics Data System (ADS)

Chen, Ting; Liebermann, Robert C.; Zou, Yongtao; Li, Ying; Qi, Xintong; Li, Baosheng

2017-08-01

The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 GPa and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach 34% and 45% for P and S wave velocities, respectively, and 64% and 75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences on silica, d(lnVP)/d(SiO2) = 0.38 (wt %)-1 and d(lnVS)/d(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.

Design and Implementation of a Prototype Microcomputer Database Management System for the Standardization of Data Elements for the Department of Defense

DTIC Science & Technology

1990-09-01

Justification Cat: Left Timeliness Identifier: Qwe (FI] Domain I Def Text: -Press [F3 to nove in/out of the fields below. Use ARROW keys to scroll- Rec: Host...Delete a record Elemont Creator ID: Justification Cat: Left Timeliness Identifier: Qwe [FI) Domain Def Text: - Press (F3) to move in/out of the...Number: 1 Alias Name: Accounting Code Data Value Type ID: QL Max Length Characters: 34 Timeliness ID: Qwe Justification Category: Left Creator ID: Domain

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory.

PubMed

Sissay, Adonay; Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J; Lopata, Kenneth

2016-09-07

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sissay, Adonay; Abanador, Paul; Mauger, François

2016-09-07

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagatingmore » the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.« less

Field Study of all GSM and WiFi Networks in Amman City from Geospatial Perspective

NASA Astrophysics Data System (ADS)

Hawarey, Mosab; Alibrahim, Mustafa; Jetto, Hamza; Salah Mahmoud, Firas

2016-04-01

A thorough field study over multiple months has been conducted in the streets of Amman, the capital city of Jordan, in order to collect massive amounts of GSM and WiFi data and analyze them from geospatial perspective. Some interesting realities have been detected; e.g. the North and West of Amman are much better served by GSM operators than the East, South, and Center. Also, the security measures taken to protect WiFi networks in the North and West are much better than those in the East, South, and Center. This has led to the recognition of an interesting pattern that groups the North and West together, while the East, South, and Center constitute another group. Extremely interesting finding was found; the GSM signals are so strong at certain locations that they constitute direct lethal threat to human health; it is scientifically documented that such strengths would lead to certain human cell mutations and cancer. The exact locations and contributors of such hazards will be disclosed in this paper for the first time. Many tabular and graphical presentations of the data will be presented.

Ionization Study of Isomeric Molecules in Strong-field Laser Pulses

DOE PAGES

Zigo, Stefan; Le, Anh-Thu; Timilsina, Pratap; ...

2017-02-10

Through the use of the technique of time-of-flight mass spectroscopy, we obtain strong-field ionization yields for randomly oriented 1,2-dichloroethylene (1,2-DCE) (C 2H 2Cl 2) and 2-butene (C 4H 8). Here, we are interested in studying the effect of conformal structure in strong-field ionization and, in particular, the role of molecular polarity. That is, we can perform strong-field ionization studies in polar vs non-polar molecules that have the same chemical composition. Here, we report our findings through the ionization yields and the ratio (trans/cis) of each stereoisomer pair as a function of intensity.

USArray Imaging of Continental Crust in the Conterminous United States

NASA Astrophysics Data System (ADS)

Ma, Xiaofei; Lowry, Anthony R.

2017-12-01

The thickness and bulk composition of continental crust provide important constraints on the evolution and dynamics of continents. Crustal mineralogy and thickness both may influence gravity anomalies, topographic elevation, and lithospheric strength, but prior to the inception of EarthScope's USArray, seismic measurements of crustal thickness and properties useful for inferring lithology are sparse. Here we improve upon a previously published methodology for joint inversion of Bouguer gravity anomalies and seismic receiver functions by using parameter space stacking of cross correlations of modeled synthetic and observed receiver functions instead of standard H-κ amplitude stacking. The new method is applied to estimation of thickness and bulk seismic velocity ratio, vP/vS, of continental crust in the conterminous United States using USArray and other broadband network data. Crustal thickness variations are reasonably consistent with those found in other studies and show interesting relationships to the history of North American continental formation. Seismic velocity ratios derived in this study are more robust than in other analyses and hint at large-scale variations in composition of continental crust. To interpret the results, we model the pressure-/temperature-dependent thermodynamics of mineral formation for various crustal chemistries, with and without volatile constituents. Our results suggest that hydration lowers bulk crustal vP/vS and density and releases heat in the shallow crust but absorbs heat in the lowermost crust (where plagioclase breaks down to pyroxene and garnet resulting in higher seismic velocity). Hence, vP/vS variations may provide a useful proxy for hydration state in the crust.

The Relationship of Field Dependent/Independent Cognitive Styles, Stimuli Variability and Time Factor on Student Achievement.

ERIC Educational Resources Information Center

Atang, Christopher I.

The effects of black and white and color illustrations on student achievement were studied to investigate the relationships between cognitive styles and instructional design. Field dependence (FD) and field independence (FI) were chosen as the cognitive style variables. Subjects were 85 freshman students in the Iowa State University Psychology…

Assessment of radio frequency exposures in schools, homes, and public places in Belgium.

PubMed

Verloock, Leen; Joseph, Wout; Goeminne, Francis; Martens, Luc; Verlaek, Mart; Constandt, Kim

2014-12-01

Characterization of exposure from emerging radio frequency (RF) technologies in areas where children are present is important. Exposure to RF electromagnetic fields (EMF) was assessed in three "sensitive" microenvironments; namely, schools, homes, and public places located in urban environments and compared to exposure in offices. In situ assessment was conducted by performing spatial broadband and accurate narrowband measurements, providing 6-min averaged electric-field strengths. A distinction between internal (transmitters that are located indoors) and external (outdoor sources from broadcasting and telecommunication) sources was made. Ninety-four percent of the broadband measurements were below 1 V m(-1). The average and maximal total electric-field values in schools, homes, and public places were 0.2 and 3.2 V m(-1) (WiFi), 0.1 and 1.1 V m(-1) (telecommunication), and 0.6 and 2.4 V m(-1) (telecommunication), respectively, while for offices, average and maximal exposure were 0.9 and 3.3 V m(-1) (telecommunication), satisfying the ICNIRP reference levels. In the schools considered, the highest maximal and average field values were due to internal signals (WiFi). In the homes, public places, and offices considered, the highest maximal and average field values originated from telecommunication signals. Lowest exposures were obtained in homes. Internal sources contributed on average more indoors (31.2%) than outdoors (2.3%), while the average contributions of external sources (broadcast and telecommunication sources) were higher outdoors (97.7%) than at indoor positions (68.8%). FM, GSM, and UMTS dominate the total downlink exposure in the outdoor measurements. In indoor measurements, FM, GSM, and WiFi dominate the total exposure. The average contribution of the emerging technology LTE was only 0.6%.

Permeability and seismic velocity and their anisotropy across the Alpine Fault, New Zealand: An insight from laboratory measurements on core from the Deep Fault Drilling Project phase 1 (DFDP-1)

NASA Astrophysics Data System (ADS)

Allen, M. J.; Tatham, D.; Faulkner, D. R.; Mariani, E.; Boulton, C.

2017-08-01

The Alpine Fault, a transpressional plate boundary between the Australian and Pacific plates, is known to rupture quasiperiodically with large magnitude earthquakes (Mw 8). The hydraulic and elastic properties of fault zones are thought to vary over the seismic cycle, influencing the nature and style of earthquake rupture and associated processes. We present a suite of laboratory permeability and P (Vp) and S (Vs) wave velocity measurements performed on fault lithologies recovered during the first phase of the Deep Fault Drilling Project (DFDP-1), which sampled principal slip zone (PSZ) gouges, cataclasites, and fractured ultramylonites, with all recovered lithologies overprinted by abundant secondary mineralization, recording enhanced fluid-rock interaction. Core material was tested in three orthogonal directions, orientated relative to the down-core axis and, when present, foliation. Measurements were conducted with pore pressure (H2O) held at 5 MPa over an effective pressure (Peff) range of 5-105 MPa. Permeabilities and seismic velocities decrease with proximity to the PSZ with permeabilities ranging from 10-17 to 10-21 m2 and Vp and Vs ranging from 4400 to 5900 m/s in the ultramylonites/cataclasites and 3900 to 4200 m/s at the PSZ. In comparison with intact country rock protoliths, the highly variable cataclastic structures and secondary phyllosilicates and carbonates have resulted in an overall reduction in permeability and seismic wave velocity, as well as a reduction in anisotropy within the fault core. These results concur with other similar studies on other mature, tectonic faults in their interseismic period.

Fusing corn nitrogen recommendation tools for an improved canopy reflectance sensor performance

USDA-ARS?s Scientific Manuscript database

Nitrogen (N) rate recommendation tools are utilized to help producers maximize corn grain yield production. Many of these tools provide recommendations at field scales but often fail when corn N requirements are variable across the field. Canopy reflectance sensors are capable of capturing within-fi...

Partitioning evapotranspiration using long-term carbon dioxide and water vapor fluxes

NASA Astrophysics Data System (ADS)

Scott, Russell L.; Biederman, Joel A.

2017-07-01

The separate components of evapotranspiration (ET) elucidate the pathways and time scales over which water is returned to the atmosphere, but ecosystem-scale measurements of transpiration (T) and evaporation (E) remain elusive. We propose a novel determination of E and T using multiyear eddy covariance estimates of ET and gross ecosystem photosynthesis (GEP). The method is applicable at water-limited sites over time periods during which a linear regression between GEP (abscissa) and ET (ordinate) yields a positive ET axis intercept, an estimate of E. At four summer-rainfall semiarid sites, T/ET increases to a peak coincident with maximum GEP and remains elevated as the growing season progresses, consistent with previous, direct measurements. The seasonal course of T/ET is related to increasing leaf area index and declining frequency of rainy days—an index of the wet surface conditions that promote E—suggesting both surface and climatic controls on ET partitioning.

Effects of Wi-Fi (2.45 GHz) Exposure on Apoptosis, Sperm Parameters and Testicular Histomorphometry in Rats: A Time Course Study.

PubMed

Shokri, Saeed; Soltani, Aiob; Kazemi, Mahsa; Sardari, Dariush; Mofrad, Farshid Babapoor

2015-01-01

In today's world, 2.45-GHz radio-frequency radiation (RFR) from industrial, scientific, medical, military and domestic applications is the main part of indoor-outdoor electromagnetic field exposure. Long-term effects of 2.45-GHz Wi-Fi radiation on male reproductive system was not known completely. Therefore, this study aimed to investigate the major cause of male infertility during short- and long-term exposure of Wi-Fi radiation. This is an animal experimental study, which was conducted in the Department of Anatomical Sciences, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, IRAN, from June to August 2014. Three-month-old male Wistar rats (n=27) were exposed to the 2.45 GHz radiation in a chamber with two Wi-Fi antennas on opposite walls. Animals were divided into the three following groups: I. control group (n=9) including healthy animals without any exposure to the antenna, II. 1-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 1 hour per day during two months and III.7-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 7 hours per day during 2 months. Sperm parameters, caspase-3 concentrations, histomorphometric changes of testis in addition to the apoptotic indexes were evaluated in the exposed and control animals. Both 1-hour and 7-hour groups showed a decrease in sperm parameters in a time dependent pattern. In parallel, the number of apoptosis-positive cells and caspase-3 activity increased in the seminiferous tubules of exposed rats. The seminal vesicle weight reduced significantly in both1-hour or 7-hour groups in comparison to the control group. Regarding to the progressive privilege of 2.45 GHz wireless networks in our environment, we concluded that there should be a major concern regarding the timedependent exposure of whole-body to the higher frequencies of Wi-Fi networks existing in the vicinity of our living places.

Ship and Installation Program: Optimal Stationing of Naval Ships

DTIC Science & Technology

2006-06-01

are those of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government. 12a. DISTRIBUTION...fi fi cf fi cff i c cf facreq STATION f i faccap MILCON VAP CONV CONV ∈ ′ ∀ ≤ + − + − ∑ ∑ ∑ and ’ , i i fu iu u UA u IS fi fi fi cf fi cf facreq...STATION AGREEN MILCON UPGRAD CONV f i ∈ ∉ ′ ≤ + + + ∀ ∑ ∑ 41 ( )’ ’ and , i u fi fi fi cff i cf fi fi uf i u u IS i i i CA AGREEN UPGRAD VAP

Effects of wi-fi signals on the p300 component of event-related potentials during an auditory hayling task.

PubMed

Papageorgiou, Charalabos C; Hountala, Chrissanthi D; Maganioti, Argiro E; Kyprianou, Miltiades A; Rabavilas, Andreas D; Papadimitriou, George N; Capsalis, Christos N

2011-06-01

The P300 component of event-related potentials (ERPs) is believed to index attention and working memory (WM) operation of the brain. The present study focused on the possible gender-related effects of Wi-Fi (Wireless Fidelity) electromagnetic fields (EMF) on these processes. Fifteen male and fifteen female subjects, matched for age and education level, were investigated while performing a modified version of the Hayling Sentence Completion test adjusted to induce WM. ERPs were recorded at 30 scalp electrodes, both without and with the exposure to a Wi-Fi signal. P300 amplitude values at 18 electrodes were found to be significantly lower in the response inhibition condition than in the response initiation and baseline conditions. Independent of the above effect, within the response inhibition condition there was also a significant gender X radiation interaction effect manifested at 15 leads by decreased P300 amplitudes of males in comparison to female subjects only at the presence of EMF. In conclusion, the present findings suggest that Wi-Fi exposure may exert gender-related alterations on neural activity associated with the amount of attentional resources engaged during a linguistic test adjusted to induce WM.

Study Centres: Key to Success of Field Dependent Learners in Africa.

ERIC Educational Resources Information Center

Wilson, Charles D.

The literature indicates that Field Independent (FI) learners are more likely than Field Dependent (FD) learners to succeed at distance education. The question can be raised: How can distance education serve people in the developing world--most of whom are probably FD? It is the author's opinion that in order for FD learners to succeed at distance…

On-body calibration and measurements using personal radiofrequency exposimeters in indoor diffuse and specular environments.

PubMed

Aminzadeh, Reza; Thielens, Arno; Bamba, Aliou; Kone, Lamine; Gaillot, Davy Paul; Lienard, Martine; Martens, Luc; Joseph, Wout

2016-07-01

For the first time, response of personal exposimeters (PEMs) is studied under diffuse field exposure in indoor environments. To this aim, both numerical simulations, using finite-difference time-domain method, and calibration measurements were performed in the range of 880-5875 MHz covering 10 frequency bands in Belgium. Two PEMs were mounted on the body of a human male subject and calibrated on-body in an anechoic chamber (non-diffuse) and a reverberation chamber (RC) (diffuse fields). This was motivated by the fact that electromagnetic waves in indoor environments have both specular and diffuse components. Both calibrations show that PEMs underestimate actual incident electromagnetic fields. This can be compensated by using an on-body response. Moreover, it is shown that these responses are different in anechoic chamber and RC. Therefore, it is advised to use an on-body calibration in an RC in future indoor PEM measurements where diffuse fields are present. Using the response averaged over two PEMs reduced measurement uncertainty compared to single PEMs. Following the calibration, measurements in a realistic indoor environment were done for wireless fidelity (WiFi-5G) band. Measured power density values are maximally 8.9 mW/m(2) and 165.8 μW/m(2) on average. These satisfy reference levels issued by the International Commission on Non-Ionizing Radiation Protection in 1998. Power density values obtained by applying on-body calibration in RC are higher than values obtained from no body calibration (only PEMs) and on-body calibration in anechoic room, by factors of 7.55 and 2.21, respectively. Bioelectromagnetics. 37:298-309, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The development of remote wireless radiation dose monitoring system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jin-woo; Chonbuk National University, Jeonjoo-Si; Jeong, Kyu-hwan

Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Somemore » of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)« less

Negative Aerosol-Cloud re Relationship From Aircraft Observations Over Hebei, China

NASA Astrophysics Data System (ADS)

Zhao, Chuanfeng; Qiu, Yanmei; Dong, Xiaobo; Wang, Zhien; Peng, Yiran; Li, Baodong; Wu, Zhihui; Wang, Yang

2018-01-01

Using six flights observations in September 2015 over Hebei, China, this study shows a robust negative aerosol-cloud droplet effective radius (re) relationship for liquid clouds, which is different from previous studies that found positive aerosol-cloud re relationship over East China using satellite observations. A total of 27 cloud samples was analyzed with the classification of clean and polluted conditions using lower and upper 1/3 aerosol concentration at 200 m below the cloud bases. By normalizing the profiles of cloud droplet re, we found significant smaller values under polluted than under clean condition at most heights. Moreover, the averaged profiles of cloud liquid water content (LWC) show larger values under polluted than clean conditions, indicating even stronger negative aerosol-cloud re relationship if LWC is kept constant. The droplet size distributions further demonstrate that more droplets concentrate within smaller size ranges under polluted conditions. Quantitatively, the aerosol-cloud interaction is found around 0.10-0.19 for the study region.

Continuous time-of-flight ion mass spectrometer

DOEpatents

Funsten, Herbert O.; Feldman, William C.

2004-10-19

A continuous time-of-flight mass spectrometer having an evacuated enclosure with means for generating an electric field located in the evacuated enclosure and means for injecting a sample material into the electric field. A source of continuous ionizing radiation injects ionizing radiation into the electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between arrival of a secondary electron out of said ionized atoms or molecules at a first predetermined location and arrival of a sample ion out of said ionized atoms or molecules at a second predetermined location.

COMAR technical information statement: expert reviews on potential health effects of radiofrequency electromagnetic fields and comments on the bioinitiative report.

PubMed

2009-10-01

The Committee on Man and Radiation (COMAR) is a technical committee of the Engineering in Medicine and Biology Society (EMBS) of the Institute of Electrical and Electronics Engineers (IEEE). Its primary area of interest is biological effects of non-ionizing electromagnetic radiation, including radiofrequency (RF) energy. The public interest in possible health effects attributed to RF energy, such as emitted by mobile phones, wireless telephone base stations, TV and radio broadcasting facilities, Wi-Fi systems and many other sources, has been accompanied by commentary in the media that varies considerably in reliability and usefulness for their audience. The focus of this COMAR Technical Information Statement is to identify quality sources of scientific information on potential health risks from exposure to RF energy. This Statement provides readers with references to expert reports and other reliable sources of information about this topic, most of which are available on the Internet. This report summarizes the conclusions from several major reports and comments on the markedly different conclusions in the BioInitiative Report (abbreviated BIR below). Since appearing on the Internet in August 2007, the BIR has received much media attention but, more recently, has been criticized by several health organizations (see Section titled "Views of health agencies about BIR"). COMAR concludes that the weight of scientific evidence in the RF bioeffects literature does not support the safety limits recommended by the BioInitiative group. For this reason, COMAR recommends that public health officials continue to base their policies on RF safety limits recommended by established and sanctioned international organizations such as the Institute of Electrical and Electronics Engineers International Committee on Electromagnetic Safety and the International Commission on Non-Ionizing Radiation Protection, which is formally related to the World Health Organization.

Scaling properties of observed and simulated satellite visible radiances

NASA Astrophysics Data System (ADS)

Barker, Howard W.; Qu, Zhipeng; Bélair, Stéphane; Leroyer, Sylvie; Milbrandt, Jason A.; Vaillancourt, Paul A.

2017-09-01

Structure functions Sq, which are related to power spectra and used to study turbulence, were computed for GOES-13 visible radiances measured on 16 May 2015 over French Guiana and adjacent Atlantic Ocean. The nested Global Environmental Multiscale (GEM) numerical weather prediction (NWP) model was run for the same time and area. Cloud data generated by GEM over (300 km)2 domains, with one-way nesting ending at horizontal grid-spacing of 0.25 km, were operated on by a 3-D solar radiative transfer model with resulting radiances degraded to GOES-13 resolution ( 1 km) and Sq computed for them, too. For GOES-13 radiances, scaling exponents ζ(2) associated with S2, for separation distances between 5 km and 25 km, were typically >0.6 for deep convective and marine boundary layer clouds and <0.4 for shallow cumuli over land. ζ(2) for GEM agreed well with GOES-13 for deep convective clouds. This suggests that the self-organizing properties of deep convection in GEM exhibit realistic geometric features, a potentially important point given the link between cloud structure and precipitation, with the latter being much more difficult to measure and assess than visible radiances. Regarding radiances for GEM's marine boundary layer clouds, their Sq differed markedly from GOES-13's; better resembling fair-weather cumulus. Likewise, GEM's shallow cumuli over land appear to have bypassed the "scattered" fair-weather stage and went straight into more organized convection. Thus, it appears that comparing time series of Sq for geostationary satellite data and corresponding modeled radiances has the potential to benefit assessment of cloud system-resolving models.

Extreme ionization of Xe clusters driven by ultraintense laser fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidenreich, Andreas; Last, Isidore; Jortner, Joshua

We applied theoretical models and molecular dynamics simulations to explore extreme multielectron ionization in Xe{sub n} clusters (n=2-2171, initial cluster radius R{sub 0}=2.16-31.0 A ring ) driven by ultraintense infrared Gaussian laser fields (peak intensity I{sub M}=10{sup 15}-10{sup 20} W cm{sup -2}, temporal pulse length {tau}=10-100 fs, and frequency {nu}=0.35 fs{sup -1}). Cluster compound ionization was described by three processes of inner ionization, nanoplasma formation, and outer ionization. Inner ionization gives rise to high ionization levels (with the formation of (Xe{sup q+}){sub n} with q=2-36), which are amenable to experimental observation. The cluster size and laser intensity dependence of themore » inner ionization levels are induced by a superposition of barrier suppression ionization (BSI) and electron impact ionization (EII). The BSI was induced by a composite field involving the laser field and an inner field of the ions and electrons, which manifests ignition enhancement and screening retardation effects. EII was treated using experimental cross sections, with a proper account of sequential impact ionization. At the highest intensities (I{sub M}=10{sup 18}-10{sup 20} W cm{sup -2}) inner ionization is dominated by BSI. At lower intensities (I{sub M}=10{sup 15}-10{sup 16} W cm{sup -2}), where the nanoplasma is persistent, the EII contribution to the inner ionization yield is substantial. It increases with increasing the cluster size, exerts a marked effect on the increase of the (Xe{sup q+}){sub n} ionization level, is most pronounced in the cluster center, and manifests a marked increase with increasing the pulse length (i.e., becoming the dominant ionization channel (56%) for Xe{sub 2171} at {tau}=100 fs). The EII yield and the ionization level enhancement decrease with increasing the laser intensity. The pulse length dependence of the EII yield at I{sub M}=10{sup 15}-10{sup 16} W cm{sup -2} establishes an ultraintense laser pulse length control mechanism of extreme ionization products.« less

Systems and methods for cylindrical hall thrusters with independently controllable ionization and acceleration stages

DOEpatents

Diamant, Kevin David; Raitses, Yevgeny; Fisch, Nathaniel Joseph

2014-05-13

Systems and methods may be provided for cylindrical Hall thrusters with independently controllable ionization and acceleration stages. The systems and methods may include a cylindrical channel having a center axial direction, a gas inlet for directing ionizable gas to an ionization section of the cylindrical channel, an ionization device that ionizes at least a portion of the ionizable gas within the ionization section to generate ionized gas, and an acceleration device distinct from the ionization device. The acceleration device may provide an axial electric field for an acceleration section of the cylindrical channel to accelerate the ionized gas through the acceleration section, where the axial electric field has an axial direction in relation to the center axial direction. The ionization section and the acceleration section of the cylindrical channel may be substantially non-overlapping.

Directed Field Ionization

NASA Astrophysics Data System (ADS)

Gregoric, Vincent C.; Kang, Xinyue; Liu, Zhimin Cheryl; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.

2017-04-01

Selective field ionization is an important experimental technique used to study the state distribution of Rydberg atoms. This is achieved by applying a steadily increasing electric field, which successively ionizes more tightly bound states. An atom prepared in an energy eigenstate encounters many avoided Stark level crossings on the way to ionization. As it traverses these avoided crossings, its amplitude is split among multiple different states, spreading out the time resolved electron ionization signal. By perturbing the electric field ramp, we can change how the atoms traverse the avoided crossings, and thus alter the shape of the ionization signal. We have used a genetic algorithm to evolve these perturbations in real time in order to arrive at a target ionization signal shape. This process is robust to large fluctuations in experimental conditions. This work was supported by the National Science Foundation under Grants No. 1607335 and No. 1607377 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number OCI-1053575.

Novel Chemical Methodology for Identifying Origin of Archeological Bitumen: Chasing the Trade Routes along the Japanese Archipelago and Sakhalin Island in Prehistory

NASA Astrophysics Data System (ADS)

Ogasawara, M.; Kato, K.

2009-04-01

We invented a novel methodology for identifying origin of archaeological bitumen by use of field-ionization mass spectrometry (FI-MS). In the FI-MS method, fragmentation of molecular ions is minimal and there is a unit charge on each molecule. Thus, the observed mass spectra directly reflect the distribution of the molecular weights of the alkane components in bitumen. The distribution could be a molecular criterion for characterizing the bitumen sources from which each bitumen sample was derived. Actually, we decomposed the FI-MS spectra by Z-numbers into several components: the Z-number refers to z in the formula CnH2n+z and 2n-z is equivalent to the deficit number of H atoms when compared to the corresponding saturated hydrocarbon, which, in turn, is correlated to the ring number in alkanes. The integrated intensities of the component spectra corresponding to the Z-number were compared to each other. The difference in the observed spectra is reflected by the difference in concentration of alkane groups with different Z-number. In this way, the intensities data of the component spectra were used as indexes to search for the origin of the bitumen. FI-MS measurements were performed on 67 samples from five different bitumen sources and 41 bitumen samples excavated from archaeological sites in Honshu and Hokkaido, the largest and the second largest island in Japan, and Sakhalin island in Russia. By use of the spectral intensities of the seven alkane components in each sample, multiple discriminant analysis was employed for the data of raw bitumen samples and excavated samples from archaeological sites. The GC-MS chromatograms obtained from the archaeological samples from the Honshu area were all consistent with the results obtained by multivariate analysis, and thus the validity of the newly developed Z-number analysis was confirmed. As for the archaeological bitumen samples in Hokkaido, It was found that bitumen from Niigata, one of the main sources in Honshu, spread to the north in 2000 BC. It reached a small island near the north end of Hokkaido. Bitumen from Sakhalin reached the central lowland in Hokkaido, but it did not go into Honshu. Bitumen from Akita, another main source in Honshu, was predominated in the northeastern part of Honshu and the Oshima peninsula located at the southeastern end of Hokkaido. The story is consistent with a strong cultural tie between the Oshima peninsula and the northern Honshu throughout the Jomon period, the long lasting cultural period in Japanese prehistory. The long trade route along the coast of the Sea of Japan is being argued due to the recent archaeological findings obtained by excavations. Our results will shed more light on the geopolitical situation in the Jomon period of the area.

Influence of field ionization effect on the divergence of laser-driven fast electrons

NASA Astrophysics Data System (ADS)

Lang, Y.; Yang, X. H.; Xu, H.; Jin, Z.; Zhuo, H. B.

2018-07-01

The effect of field ionization on the divergence of fast electrons (E k ≥ 50 keV), driven by ultrashort-ultraintense laser pulse interaction with plasma, is studied by using 2D3V particle-in-cell simulations. It is found that, due to temperature anisotropy of the fast electrons in the ionizing target, strong fluctuant magnetic fields in the preplasma region is generated through Weibel instability. In turn, the field induces an enhancement of the hot electron divergence for the target with ionization process. Meanwhile, compared with the target without an ionization process, larger divergence of hot electrons can also be seen in the ionizing target with laser intensity varying from 5 × 1019 W/cm2 to 5 × 1020 W/cm2 and the divergence is weakly dependent on target materials for a fixed profile of preplasma. The results here are useful for the application of laser-driven fast electron beams.

Correlated electron and nuclear dynamics in strong field photoionization of H(2)(+).

PubMed

Silva, R E F; Catoire, F; Rivière, P; Bachau, H; Martín, F

2013-03-15

We present a theoretical study of H(2)(+) ionization under strong IR femtosecond pulses by using a method designed to extract correlated (2D) photoelectron and proton kinetic energy spectra. The results show two distinct ionization mechanisms-tunnel and multiphoton ionization-in which electrons and nuclei do not share the energy from the field in the same way. Electrons produced in multiphoton ionization share part of their energy with the nuclei, an effect that shows up in the 2D spectra in the form of energy-conservation fringes similar to those observed in weak-field ionization of diatomic molecules. In contrast, tunneling electrons lead to fringes whose position does not depend on the proton kinetic energy. At high intensity, the two processes coexist and the 2D plots show a very rich behavior, suggesting that the correlation between electron and nuclear dynamics in strong field ionization is more complex than one would have anticipated.

3D electrostatic gyrokinetic electron and fully kinetic ion simulation of lower-hybrid drift instability of Harris current sheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhenyu; Lin, Yu; Wang, Xueyi

The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current sheet with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic electron and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-electron mass ratio m i/m e. In contrast to the fully kinetic PIC simulation scheme, the fast electron cyclotron motion and plasma oscillations are systematically removed in the GeFi model, and hence one can employ the realistic m i/m e. The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location wheremore » $$\\vec{k}$$• $$\\vec{B}$$ =0, consistent with previous analytical and simulation studies. Here, $$\\vec{B}$$ is the equilibrium magnetic field and $$\\vec{k}$$ is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at $$\\vec{k}$$ •$$\\vec{B}$$ ≠0. Additionally, the simulation results indicate that varying m i/m e, the current sheet width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.« less

3D electrostatic gyrokinetic electron and fully kinetic ion simulation of lower-hybrid drift instability of Harris current sheet

DOE PAGES

Wang, Zhenyu; Lin, Yu; Wang, Xueyi; ...

2016-07-07

The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current sheet with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic electron and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-electron mass ratio m i/m e. In contrast to the fully kinetic PIC simulation scheme, the fast electron cyclotron motion and plasma oscillations are systematically removed in the GeFi model, and hence one can employ the realistic m i/m e. The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location wheremore » $$\\vec{k}$$• $$\\vec{B}$$ =0, consistent with previous analytical and simulation studies. Here, $$\\vec{B}$$ is the equilibrium magnetic field and $$\\vec{k}$$ is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at $$\\vec{k}$$ •$$\\vec{B}$$ ≠0. Additionally, the simulation results indicate that varying m i/m e, the current sheet width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.« less

Electron spin resonance observation of charge carrier concentration in organic field-effect transistors during device operation

NASA Astrophysics Data System (ADS)

Tanaka, Hisaaki; Hirate, Masataka; Watanabe, Shun-ichiro; Kaneko, Kazuaki; Marumoto, Kazuhiro; Takenobu, Taishi; Iwasa, Yoshihiro; Kuroda, Shin-ichi

2013-01-01

Charge carrier concentration in operating organic field-effect transistors (OFETs) reflects the electric potential within the channel, acting as a key quantity to clarify the operation mechanism of the device. Here, we demonstrate a direct determination of charge carrier concentration in the operating devices of pentacene and poly(3-hexylthiophene) (P3HT) by field-induced electron spin resonance (FI-ESR) spectroscopy. This method sensitively detects polarons induced by applying gate voltage, giving a clear FI-ESR signal around g=2.003 in both devices. Upon applying drain-source voltage, carrier concentration decreases monotonically in the FET linear region, reaching about 70% of the initial value at the pinch-off point, and stayed constant in the saturation region. The observed results are reproduced well from the theoretical potential profile based on the gradual channel model. In particular, the carrier concentration at the pinch-off point is calculated to be β/(β+1) of the initial value, where β is the power exponent in the gate voltage (Vgs) dependence of the mobility (μ), expressed as μ∝Vgsβ-2, providing detailed information of charge transport. The present devices show β=2.6 for the pentacene and β=2.3 for the P3HT cases, consistent with those determined by transfer characteristics. The gate voltage dependence of the mobility, originating from the charge trapping at the device interface, is confirmed microscopically by the motional narrowing of the FI-ESR spectra.

The Relationship between the Learning Strategies and Learning Styles in a Hypermedia Environment.

ERIC Educational Resources Information Center

Liu, Min; Reed, W. Michael

Different learning strategies that are used by field-independent (FI) and field-dependent (FD) people in a hypermedia-assisted instructional setting were studied with 63 international college students for whom English was a second language. The treatment was a semantic network-based hypermedia-assisted language-learning environment to help…

Low-Pressure, Field-Ionizing Mass Spectrometer

NASA Technical Reports Server (NTRS)

Hartley, Frank; Smith, Steven

2009-01-01

A small mass spectrometer utilizing a miniature field ionization source is now undergoing development. It is designed for use in a variety of applications in which there are requirements for a lightweight, low-power-consumption instrument that can analyze the masses of a wide variety of molecules and ions. The device can operate without need for a high-vacuum, carrier-gas feed radioactive ionizing source, or thermal ionizer. This mass spectrometer can operate either in the natural vacuum of outer space or on Earth at any ambient pressure below 50 torr (below about 6.7 kPa) - a partial vacuum that can easily be reached by use of a small sampling pump. This mass spectrometer also has a large dynamic range - from singly charged small gas ions to deoxyribonucleic acid (DNA) fragments larger than 104 atomic mass units - with sensitivity adequate for detecting some molecules and ions at relative abundances of less than one part per billion. This instrument (see figure) includes a field ionizer integrated with a rotating-field mass spectrometer (RFMS). The field ionizer effects ionization of a type characterized as "soft" in the art because it does not fragment molecules or initiate avalanche arcing. What makes the "soft" ionization mode possible is that the distance between the ionizing electrodes is less than mean free path for ions at the maximum anticipated operating pressure, so that the ionizer always operates on the non-breakdown side of the applicable Paschen curve (a standard plot of breakdown potential on the ordinate and pressure electrode separation on the abscissa). The field ionizer in this instrument is fabricated by micromachining a submicron-thick membrane out of an electrically nonconductive substrate, coating the membrane on both sides to form electrodes, then micromachining small holes through the electrodes and membrane. Because of the submicron electrode separation, even a potential of only 1 V applied between the electrodes gives rise to an electric field with a strength of in excess of a megavolt per meter strong enough to ionize any gas molecules passing through the holes. An accelerator grid and an electrostatic deflector focus the ions from the field ionizer into the rotating-field cell of the RFMS. The potentials applied to the electrodes of the cell to generate the rotating electric field typically range from 1 to 13 V. The ions travel in well-defined helices within this cell, after which they are collected in a Faraday cup. The mass of most of the molecules reaching the Faraday cup decreases with increasing frequency of rotation of the electric field in the cell. Therefore, the frequency of rotation of the electric field is made to vary in order to scan through a desired range of ion masses: For example, lightweight gas molecules are scanned at frequencies in the megahertz range, while DNA and other large organic molecules are scanned at kilohertz frequencies.

Nonsequential double ionization with mid-infrared laser fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ying -Bin; Wang, Xu; Yu, Ben -Hai

Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Here, some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the finalmore » energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.« less

Nonsequential double ionization with mid-infrared laser fields

DOE PAGES

Li, Ying -Bin; Wang, Xu; Yu, Ben -Hai; ...

2016-11-18

Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Here, some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the finalmore » energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.« less

A spatiotemporal analysis of the relationship between near-surface air temperature and satellite land surface temperatures using 17 years of data from the ATSR series

NASA Astrophysics Data System (ADS)

Good, Elizabeth J.; Ghent, Darren J.; Bulgin, Claire E.; Remedios, John J.

2017-09-01

The relationship between satellite land surface temperature (LST) and ground-based observations of 2 m air temperature (T2m) is characterized in space and time using >17 years of data. The analysis uses a new monthly LST climate data record (CDR) based on the Along-Track Scanning Radiometer series, which has been produced within the European Space Agency GlobTemperature project (http://www.globtemperature.info/). Global LST-T2m differences are analyzed with respect to location, land cover, vegetation fraction, and elevation, all of which are found to be important influencing factors. LSTnight ( 10 P.M. local solar time, clear-sky only) is found to be closely coupled with minimum T2m (Tmin, all-sky) and the two temperatures generally consistent to within ±5°C (global median LSTnight-Tmin = 1.8°C, interquartile range = 3.8°C). The LSTday ( 10 A.M. local solar time, clear-sky only)-maximum T2m (Tmax, all-sky) variability is higher (global median LSTday-Tmax = -0.1°C, interquartile range = 8.1°C) because LST is strongly influenced by insolation and surface regime. Correlations for both temperature pairs are typically >0.9 outside of the tropics. The monthly global and regional anomaly time series of LST and T2m—which are completely independent data sets—compare remarkably well. The correlation between the data sets is 0.9 for the globe with 90% of the CDR anomalies falling within the T2m 95% confidence limits. The results presented in this study present a justification for increasing use of satellite LST data in climate and weather science, both as an independent variable, and to augment T2m data acquired at meteorological stations.

Numerical Investigation on Absorption Enhancement of Black Carbon Aerosols Partially Coated With Nonabsorbing Organics

NASA Astrophysics Data System (ADS)

Zhang, Xiaolin; Mao, Mao; Yin, Yan; Wang, Bin

2018-01-01

This study numerically evaluates the effects of aerosol microphysics, including coated volume fraction of black carbon (BC), shell/core ratio, and size distribution, on the absorption enhancement (Eab) of polydisperse BC aggregates partially coated by organics, which is calculated by the exact multiple-sphere T-matrix method. The coated volume fraction of BC plays a substantial role in determining the absorption enhancement of partially coated BC aggregates, which typically have an Eab in the range of 1.0-2.0 with a larger value for larger coated volume fraction of BC as the shell/core ratio, BC geometry, and size distribution are fixed. The shell/core ratio, BC geometry, and size distribution have little impact on the Eab of coated BC with small coated volume fraction of BC, while they become significant for large coated volume fraction of BC. The Eab of partially coated BC particles can be slightly less than 1.0 for the large BC in the accumulation mode exhibiting large shell/core ratio and small coated volume fraction of BC, indicating that the absorption shows even slight decrease relative to uncoated BC particles. For partially coated BC aggregates in the accumulation and coarse modes, the refractive index uncertainties of BC result in the Eab differences of less than 9% and 2%, respectively, while those of organics can induce larger variations with the maximum differences up to 22% and 18%, respectively. Our study indicates that accounting for particle coating microphysics, particularly the coated volume fraction of BC, can potentially help to understand the differences in observations of largely variable absorption enhancements over various regions.

Satellite Evidence that E. huxleyi Phytoplankton Blooms Weaken Marine Carbon Sinks

NASA Astrophysics Data System (ADS)

Kondrik, D. V.; Pozdnyakov, D. V.; Johannessen, O. M.

2018-01-01

Phytoplankton blooms of the coccolithophore Emiliania huxleyi are known to produce CO2, causing less uptake of atmospheric CO2 by the ocean, but a global assessment of this phenomenon has so far not been quantified. Therefore, here we quantify the increase in CO2 partial pressure (ΔpCO2) at the ocean surface within E. huxleyi blooms for polar and subpolar seas using an 18 year ocean color time series (1998-2015). When normalized to pCO2 in the absence of bloom, the mean and maximum ΔpCO2 values within the bloom areas varied between 21.0%-43.3% and 31.6%-62.5%, respectively. These results might have appreciable implications for climatology, marine chemistry, and ecology.

A frailty index based on laboratory deficits in community-dwelling men predicted their risk of adverse health outcomes.

PubMed

Blodgett, Joanna M; Theou, Olga; Howlett, Susan E; Wu, Frederick C W; Rockwood, Kenneth

2016-07-01

abnormal laboratory test results accumulate with age and can be common in people with few clinically detectable health deficits. A frailty index (FI) based entirely on common physiological and laboratory tests (FI-Lab) might offer pragmatic and scientific advantages compared with a clinical FI (FI-Clin). to compare the FI-Lab with the FI-Clin and to assess their individual and combined relationships with mortality and other adverse health outcomes. secondary analysis of the eight-centre, longitudinal European Male Ageing Study (EMAS) of community-dwelling men aged 40-79 at baseline. Follow-up assessment occurred 4.4 ± 0.3 (mean ± SD) years later. we constructed a 23-item FI using common laboratory tests, blood pressure and pulse (FI-Lab), compared it with a previously validated 39-item FI using self-report and performance-based measures (FI-Clin) and finally combined both FIs to create a 62-item FI-Combined. Outcomes were all-cause mortality, institutionalisation, doctor visits, medication use, self-reported health, falls and fractures. the mean FI-Lab score was 0.28 ± 0.11, the FI-Clin was 0.13 ± 0.11 and FI-Combined was 0.19 ± 0.09. Age-adjusted models demonstrated that each FI was associated with mortality [HR (CI) FI-Lab: 1.04 (1.03-1.06); FI-Clin: 1.05 (1.04-1.06); FI-Combined: 1.07 (1.06-1.09)], institutionalisation, doctor visits, medication use, self-reported health and falls. Combined in a model with FI-Clin, the FI-Lab remained independently associated with mortality, institutionalisation, doctor visits, medication use and self-reported health. the FI-Lab detected an increased risk of adverse health outcomes alone and in combination with a clinical FI; further evaluation of the feasibility of the FI-Lab as a frailty screening tool within hospital care settings is needed. © The Author 2016. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Probing electron delays in above-threshold ionization

DOE PAGES

Zipp, Lucas J.; Natan, Adi; Bucksbaum, Philip H.

2014-11-21

Recent experiments have revealed attosecond delays in the emission of electrons from atoms ionized by extreme UV light, offering a glimpse into the ultrafast nature of light-induced electron dynamics. In this work, we extend these measurements to the strong-field above-threshold ionization (ATI) regime, by measuring delays in the photoemission of electrons from argon in the presence of an intense laser field. We probe the ATI process with a weak coherent reference, at half the laser frequency. The interfering ionization signal reveals the relative spectral phase of adjacent ATI channels, with an equivalent resolution of a few attoseconds. These relative delaysmore » depend on the strong field, and approach zero at higher intensity. Our phase measurements of ATI electrons show how strong fields alter ionization dynamics in atoms.« less

Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique.

PubMed

Dupuis, Alexandre; Mazhorova, Anna; Désévédavy, Frédéric; Rozé, Mathieu; Skorobogatiy, Maksim

2010-06-21

We report two novel fabrication techniques, as well as THz spectral transmission and propagation loss measurements of subwavelength plastic wires with highly porous (up to 86%) and non-porous transverse geometries. The two fabrication techniques we describe are based on the microstructured molding approach. In one technique the mold is made completely from silica by stacking and fusing silica capillaries to the bottom of a silica ampoule. The melted material is then poured into the silica mold to cast the microstructured preform. Another approach uses a microstructured mold made of a sacrificial plastic which is co-drawn with a cast preform. Material from the sacrificial mold is then dissolved after fi ber drawing. We also describe a novel THz-TDS setup with an easily adjustable optical path length, designed to perform cutback measurements using THz fibers of up to 50 cm in length. We fi nd that while both porous and non-porous subwavelength fibers of the same outside diameter have low propagation losses (alpha

Exposure to radio frequency electromagnetic fields from wireless computer networks: duty factors of Wi-Fi devices operating in schools.

PubMed

Khalid, M; Mee, T; Peyman, A; Addison, D; Calderon, C; Maslanyj, M; Mann, S

2011-12-01

The growing use of wireless local area networks (WLAN) in schools has prompted a study to investigate exposure to the radio frequency (RF) electromagnetic fields from Wi-Fi devices. International guidelines on limiting the adverse health effects of RF, such as those of ICNIRP, allow for time-averaging of exposure. Thus, as Wi-Fi signals consist of intermittent bursts of RF energy, it is important to consider the duty factors of devices in assessing the extent of exposure and compliance with guidelines. Using radio packet capture methods, the duty factor of Wi-Fi devices has been assessed in a sample of 6 primary and secondary schools during classroom lessons. For the 146 individual laptops investigated, the range of duty factors was from 0.02 to 0.91%, with a mean of 0.08% (SD 0.10%). The duty factors of access points from 7 networks ranged from 1.0% to 11.7% with a mean of 4.79% (SD 3.76%). Data gathered with transmit time measuring devices attached to laptops also showed similar results. Within the present limited sample, the range of duty factors from laptops and access points were found to be broadly similar for primary and secondary schools. Applying these duty factors to previously published results from this project, the maximum time-averaged power density from a laptop would be 220 μW m(-2), at a distance of 0.5 m and the peak localised SAR predicted in the torso region of a 10 year old child model, at 34 cm from the antenna, would be 80 μW kg(-1). Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Near- and far-field infrasound monitoring in the Mediterranean area

NASA Astrophysics Data System (ADS)

Campus, Paola; Marchetti, Emanuele; Le Pichon, Alexis; Wallenstein, Nicolau; Ripepe, Maurizio; Kallel, Mohamed; Mialle, Pierrick

2013-04-01

The Mediterranean area is characterized by a number of very interesting sources of infrasound signals and offers a promising playground for the development of a deeper understanding of such sources and of the associated propagation models. The progress in the construction and certification of infrasound arrays belonging to the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in the vicinity of this area has been complemented, in the last decade, by the construction of infrasound arrays established by several European research groups. The University of Florence (UniFi) plays a crucial role for the detection of infrasound signals in the Mediterranean area, having deployed since several years two infrasound arrays on Stromboli and Etna volcanoes, and, more recently, three infrasound arrays in the Alpine area of NW Italy and one infrasound array on the Apennines (Mount Amiata), designed and established in the framework of the ARISE Project. The IMS infrasound arrays IS42 (Graciosa, Azores, Portugal) and IS48 (Kesra, Tunisia) recorded, since the time of their certification, a number of far-field events which can be correlated with some near-field records of the infrasound arrays belonging to UniFi. An analysis of the results and potentialities of infrasound source's detections in near and far-field realized by IS42, IS48 and UniFi arrays in the Mediterranean area, with special focus on volcanic events is presented. The combined results deriving from the analysis of data recorded by the Unifi arrays and by the IS42 and IS48 arrays, in collaboration with the Department of Analyse et Surveillance (CEA/DASE), will generate a synergy which will certainly contribute to the progress of the ARISE Project.

Interpretation of the electric fields measured in an ionospheric critical ionization velocity experiment

NASA Technical Reports Server (NTRS)

Brenning, N.; Faelthammar, C.-G.; Marklund, G.; Haerendel, G.; Kelley, M. C.; Pfaff, R.

1991-01-01

The quasi-dc electric fields measured in the CRIT I ionospheric release experiment are studied. In the experiment, two identical barium shaped charges were fired toward a main payload, and three-dimensional measurements of the electric field inside the streams were made. The relevance of proposed mechanisms for electron heating in the critical ionization velocity (CIV) mechanism is addressed. It is concluded that both the 'homogeneous' and the 'ionizing front' models probably are valid, but in different parts of the streams. It is also possible that electrons are directly accelerated by a magnetic field-aligned component of the electric field. The coupling between the ambient ionosphere and the ionized barium stream is more complicated that is usually assumed in CIV theories, with strong magnetic-field-aligned electric fields and probably current limitation as important processes.

Design and construction of shoulder recesses into the beam aperture shields for improved patient positioning at the FiR 1 BNCT facility.

PubMed

Auterinen, I; Kotiluoto, P; Hippeläinen, E; Kortesniemi, M; Seppälä, T; Serén, T; Mannila, V; Pöyry, P; Kankaanranta, L; Collan, J; Kouri, M; Joensuu, H; Savolainen, S

2004-11-01

Improvements have been made at the FiR 1 BNCT facility to ease the positioning of the patient with a tumor in the head and neck region into a lateral neutron beam. Shoulder recesses were constructed horizontally on both sides of the beam aperture. When shoulder recesses are not needed, they are filled with neutron attenuating filling blocks. MCNP simulations using an anthropomorphic human model BOMAB phantom showed that the main contribution to the increase in the effective dose to the patient's body due to the shoulder recesses was from the neutron dose of the arm. In a position when one arm is inside the shoulder recess, the maximal effective dose of the patient was estimated to be 0.7Sv/h. Dose measurements using the twin ionization chamber technique showed that the neutron dose increased on the sides as predicted by the MCNP model but there was no noticeable change in the gamma doses. When making the recesses into the lithium containing neutron shield material tritium contamination was confined using an underpressurized glove box and machine tools with local exhaust. The shoulder recesses give space for more flexible patient positioning and can be considered as a significant improvement of the Finnish BNCT facility.

Observation of ionization enhancement in two-color circularly polarized laser fields

NASA Astrophysics Data System (ADS)

Mancuso, Christopher A.; Dorney, Kevin M.; Hickstein, Daniel D.; Chaloupka, Jan L.; Tong, Xiao-Min; Ellis, Jennifer L.; Kapteyn, Henry C.; Murnane, Margaret M.

2017-08-01

When atoms are irradiated by two-color circularly polarized laser fields the resulting strong-field processes are dramatically different than when the same atoms are irradiated by a single-color ultrafast laser. For example, electrons can be driven in complex two-dimensional trajectories before rescattering or circularly polarized high harmonics can be generated, which was once thought impossible. Here, we show that two-color circularly polarized lasers also enable control over the ionization process itself and make a surprising finding: the ionization rate can be enhanced by up to 700 % simply by switching the relative helicity of the two-color circularly polarized laser field. This enhancement is experimentally observed in helium, argon, and krypton over a wide range of intensity ratios of the two-color field. We use a combination of advanced quantum and fully classical calculations to explain this ionization enhancement as resulting in part due to the increased density of excited states available for resonance-enhanced ionization in counter-rotating fields compared with co-rotating fields. In the future, this effect could be used to probe the excited state manifold of complex molecules.

Level crossings in the ionization of H(2) Rydberg molecules at a metal surface.

PubMed

McCormack, E A; Ford, M S; Softley, T P

2010-10-28

The ionization of H(2) Rydberg states at a metal surface is investigated using a molecular beam incident at grazing incidence on a gold surface. The H(2) molecules, excited by stepwise two-color laser excitation, are selected in each of the accessible Stark eigenstates of the N(+) = 2, n = 17 Rydberg manifold in turn and the ionization at the surface is characterized by applying a field to extract the ions formed. Profiles of extracted ion signal versus applied field show resonances that can be simulated by assuming an enhancement of surface ionization at fields corresponding to energy-level crossings between the populated N(+) = 2 manifold and the near-degenerate N(+) = 0 Stark manifolds. It is concluded that the slow (microsecond time scale) rotation-electronic energy transfer to N(+) = 0 states occurring at these crossings takes place in the time interval following application of the field ramp when the molecule is still distant from, and unperturbed by, the surface. However, the energy levels are strongly perturbed by image-dipole interactions as the molecule approaches close to the surface, leading to additional energy-level crossings. Adiabatic behavior at such crossings affects the intensity of the observed resonances in the surface ionization signal but not their field positions. Resonances are also observed in the surface ionization profiles at fields above the field-ionization threshold; some of these show asymmetric "Fano-type" line shapes due to quantum interference in the nonradiative coupling to degenerate bound and continuum states.

High-Pressure Granulite Facies Overprinting During the Exhumation of Eclogites in the Bangong-Nujiang Suture Zone, Central Tibet: Link to Flat-Slab Subduction

NASA Astrophysics Data System (ADS)

Zhang, Xiu-Zheng; Wang, Qiang; Dong, Yong-Sheng; Zhang, Chunfu; Li, Qing-Yun; Xia, Xiao-Ping; Xu, Wang

2017-12-01

The geometric transformation of a descending plate, such as from steep to flat subduction in response to a change from normal to overthickened oceanic crust during subduction, is a common and important geological process at modern or fossil convergent margins. However, the links between this process and the metamorphic evolution of the exhumation of oceanic (ultra)high-pressure eclogites are poorly understood. Here we report detailed petrological, mineralogical, phase equilibria, and secondary ion mass spectrometry zircon and rutile U-Pb age data for the Dong Co eclogites at the western segment of the Bangong-Nujiang suture zone, central Tibet. Our data reveal that the Dong Co eclogites experienced peak eclogite-facies metamorphism (T = 610-630°C, P = 2.4-2.6 GPa) and underwent multiple stages of retrograde metamorphism. P-T pseudosections and compositional isopleths of garnet define a complex clockwise P-T-t path (including two stages of decompression-dominated P-T path and one of isobaric heating), suggesting varying exhumation velocities. Combining previous studies with our new results, we suggest that the transformation from rapid to slow exhumation is dominated by the transition from steep to flat subduction. The flat-slab segment, caused by subduction of buoyant oceanic plateau, led to an extremely slow exhumation and a strong overprinting of HP granulite facies at a depth of 50 km at 177 Ma. The slab rollback that followed in response to a substantial density increase of the eclogitized oceanic plateau resulted in another rapid exhumation process at 168 Ma and triggered the formation of abundant near-simultaneous or later magmatic rocks.

Investigation of the Electron Density Variation During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Reinisch, B. W.; Dandenault, P. B.; Galkin, I. A.; Hamel, R.; Richards, P. G.

2018-02-01

This paper presents a comparison of modeled and measured electron densities for the 21 August 2017 solar eclipse across the USA. The location of the instrument was (43.81°N, 247.32°E) where the maximum obscuration of 99.6% occurred at 17.53 hr UT on 21 August. The solar apparent time was 9.96 hr, and the duration of the eclipse was 2.7 hr. It was found that if it is assumed that there are no chromosphere emissions at totality, 30% coronal emission remaining at totality gave the best fit to the electron density variation at 150 km. The 30% coronal emission estimate has uncertainties associated with respect to uncertainties in the solar spectrum, the measured electron density, and the amount of chromosphere emissions remaining at totality. The agreement between the modeled and measured electron densities is excellent at 150 km with the assumed 30% coronal emission at totality. At other altitudes, the agreement is very good, but the altitude profile would be improved if the model peak electron density (NmF2) decayed more slowly to better match the data. The minimum NmF2 in the model occurs 10 min after totality when it decreases to 0.55 from its noneclipse value. The minimum of the NmF2 data occurs between 6 and 10 min after totality but is 15% larger. The total electron content decreases to 0.65 of its preeclipse value. These relative changes agree well with those predicted by others prior to the eclipse.

Do the Eyes Have It? Using Eye Tracking to Assess Students Cognitive Dimensions

ERIC Educational Resources Information Center

Nisiforou, Efi A.; Laghos, Andrew

2013-01-01

Field dependence/independence (FD/FI) is a significant dimension of cognitive styles. The paper presents results of a study that seeks to identify individuals' level of field independence during visual stimulus tasks processing. Specifically, it examined the relationship between the Hidden Figure Test (HFT) scores and the eye tracking metrics.…

Effects of Field Instructor Training on Student Competencies and the Supervisory Alliance

ERIC Educational Resources Information Center

Deal, Kathleen Holtz; Bennett, Susanne; Mohr, Jonathan; Hwang, Jeongha

2011-01-01

Objectives: This study of a field instructor (FI) training model, offered at two universities, focused on the relationship between student competencies, the supervisory alliance, and students' attachment styles. Method: The study used a pretest-posttest follow-up design of 100 randomly assigned FIs (training group = 48; control group = 52) and 64…

Ionization of Rydberg atoms colliding with a metal surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjakste, J.; Borisov, A. G.; Gauyacq, J. P.

2006-04-15

We report on a theoretical study of the ionization process of Xe* Rydberg atoms colliding with a metal surface, in the presence of an external electric field. The evolution of the Xe* outer electron is studied by a wave packet propagation approach, allowing to include all dynamical aspects of the collision, in particular nonadiabatic inter-Rydberg transitions. We investigate how the different Xe* Stark states formed in the external field couple together and ionize on the surface and how the different polarizations of the electronic cloud in the Xe* states are reflected in their ionization properties. We show that the presencemore » of the external electric field can significantly perturb the dynamics of the ionization process. Our results account for recent results from Dunning et al. [Nucl. Inst. Meth. B 203, 69 (2003)]. In particular, it is explained how the external electric field present in the experimental procedure of Dunning et al. leads to the apparent absence of a polarization effect in the ionization process.« less

Exposure to radio-frequency electromagnetic waves alters acetylcholinesterase gene expression, exploratory and motor coordination-linked behaviour in male rats.

PubMed

Obajuluwa, Adejoke Olukayode; Akinyemi, Ayodele Jacob; Afolabi, Olakunle Bamikole; Adekoya, Khalid; Sanya, Joseph Olurotimi; Ishola, Azeez Olakunle

2017-01-01

Humans in modern society are exposed to an ever-increasing number of electromagnetic fields (EMFs) and some studies have demonstrated that these waves can alter brain function but the mechanism still remains unclear. Hence, this study sought to investigate the effect of 2.5 Ghz band radio-frequency electromagnetic waves (RF-EMF) exposure on cerebral cortex acetylcholinesterase (AChE) activity and their mRNA expression level as well as locomotor function and anxiety-linked behaviour in male rats. Animals were divided into four groups namely; group 1 was control (without exposure), group 2-4 were exposed to 2.5 Ghz radiofrequency waves from an installed WI-FI device for a period of 4, 6 and 8 weeks respectively. The results revealed that WiFi exposure caused a significant increase in anxiety level and affect locomotor function. Furthermore, there was a significant decrease in AChE activity with a concomitant increase in AChE mRNA expression level in WiFi exposed rats when compared with control. In conclusions, these data showed that long term exposure to WiFi may lead to adverse effects such as neurodegenerative diseases as observed by a significant alteration on AChE gene expression and some neurobehavioral parameters associated with brain damage.

Indocyanine green fluorescence-guided surgery after IV injection in metastatic colorectal cancer: A systematic review.

PubMed

Liberale, G; Bourgeois, P; Larsimont, D; Moreau, M; Donckier, V; Ishizawa, T

2017-09-01

Indocyanine green fluorescence-guided surgery (ICG-FGS) has emerged as a potential new imaging modality for improving the detection of hepatic, lymph node (LN), and peritoneal metastases in colorectal cancer (CRC) patients. The aim of this paper is to review the available literature in the clinical setting of ICG-FGS for tumoral detection in various fields of metastatic colorectal disease. PubMed and Medline literature databases were searched for original articles on the use of ICG in the setting of clinical studies on colorectal cancer. The search terms used were "near-infrared fluorescence", "intraoperative imaging", "indocyanine green", "human" and "colorectal cancer". ICG fluorescence imaging (ICG-FI) is clearly supported as an intraoperative technique that allows the detection of additional superficial hepatic metastases of CRC. Data on the role of ICG-FI in the intraoperative detection of peritoneal metastases and LN metastases are scarce but encouraging and ICG-FI could potentially improve the staging and treatment of these patients. ICG-FI is a promising imaging technique in the detection of small infraclinic LN, hepatic, and peritoneal metastatic deposits that may allow better staging and more complete surgical resection with a potential prognostic benefit for patients. Copyright © 2017 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Seismotectonics of the 2014 Chiang Rai, Thailand, earthquake sequence

NASA Astrophysics Data System (ADS)

Pananont, P.; Herman, M. W.; Pornsopin, P.; Furlong, K. P.; Habangkaem, S.; Waldhauser, F.; Wongwai, W.; Limpisawad, S.; Warnitchai, P.; Kosuwan, S.; Wechbunthung, B.

2017-08-01

On 5 May 2014, a Mw 6.2 strike-slip earthquake occurred in the Mae Lao region of Chiang Rai province in Thailand. This earthquake took place in a region of known faults and caused substantial damage and injuries, although the region had been previously identified as having a relatively low earthquake hazard. Detailed field reconnaissance and deployment of a dense, temporary, network of broadband seismometers allowed details of the damage and its relationship to seismicity to be analyzed. The aftershock sequence associated with this main shock occurs on two well-defined trends, reflecting the two potential fault planes in earthquake mechanisms for the main shock and the majority of the aftershocks. The damage area was relatively large for an event of this magnitude, but building damage was largely limited to the primary rupture region, while liquefaction and other ground failure are spatially associated with the rupture area and along regional rivers. Stress modeling, combined with the time series and pattern of aftershock activity, leads us to propose that slip near the northern termination of the main shock rupture continued slightly onto a conjugate fault, helping to trigger the distinct pattern of two discrete, conjugate trends of aftershock activity that mirror the kinematics of the main shock fault mechanism.

How much have California winters warmed over the last century?

NASA Astrophysics Data System (ADS)

Wang, K. J.; Williams, A. P.; Lettenmaier, D. P.

2017-09-01

Extraordinarily warm 2013-2014 and 2014-2015 winter temperatures in California accompanied by drought conditions contributed to low snow accumulations and stressed water resources, giving rise to the question: how much has California's climate warmed over the last century? We examine long-term trends in maximum (Tmax) and minimum (Tmin) daily temperatures in winter estimated from five gridded data sets. Resulting trends show some consistent features, such as higher trends in Tmin than Tmax; however, substantial differences exist in the trend magnitudes and spatial patterns due mostly to the nature of spatial interpolation employed in the different data sets. Averaged across California over 1920-2015, Tmax trends vary from -0.30 to 1.2°C/century, while Tmin trends range from 1.2 to 1.9°C/century. The differences in temperature strongly impact modeled changes in snow water equivalent over the last century (from -5.0 to -7.6 km3/century).

Effectiveness of crack sealing on pavement serviceability and life.

DOT National Transportation Integrated Search

2011-06-01

This report presents the details of a study to evaluate effectiveness of Ohio Department of Transportations prevailing crack sealing program. Evaluation was performed through field monitoring a large number of crack sealed and control sections. Fi...

Individual and population intake fractions of diesel particulate matter (DPM) in bus stop microenvironments.

PubMed

Xu, Jia; Jin, Taosheng; Miao, Yaning; Han, Bin; Gao, Jiajia; Bai, Zhipeng; Xu, Xiaohong

2015-12-01

Diesel particulate matter (DPM) is associated with adverse human health effects. This study aims to investigate the relationship between DPM exposure and emissions by estimating the individual intake fraction (iFi) and population intake fraction (iFp) of DPM. Daily average concentrations of particulate matter at two bus stops during rush hours were measured, and then they were apportioned to DPM due to heavy-duty diesel bus emissions using Chemical Mass Balance Model. The DPM emissions of diesel buses for different driving conditions (idling, creeping and traveling) were estimated on the basis of field observations and published emission factors. The median iFi of DPM was 0.67 and 1.39 per million for commuters standing at the bus stop and pedestrians/cyclists passing through the bus stop during rush hours, respectively. The median iFp of DPM was 94 per million. Estimations of iFi and iFp of DPM are potentially significant for exposure assessment and risk management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fayet-Iliopoulos terms in supergravity and D-term inflation

NASA Astrophysics Data System (ADS)

Antoniadis, I.; Chatrabhuti, A.; Isono, H.; Knoops, R.

2018-05-01

We analyse the consequences of a new gauge invariant Fayet-Iliopoulos (FI) term proposed recently to a class of inflation models driven by supersymmetry breaking with the inflaton being the superpartner of the goldstino. We first show that charged matter fields can be consistently added with the new term, as well as the standard FI term in supergravity in a Kähler frame where the U(1) is not an R-symmetry. We then show that the slow-roll conditions can be easily satisfied with inflation driven by a D-term depending on the two FI parameters. Inflation starts at initial conditions around the maximum of the potential where the U(1) symmetry is restored and stops when the inflaton rolls down to the minimum describing the present phase of our Universe. The resulting tensor-to-scalar ratio of primordial perturbations can be even at observable values in the presence of higher order terms in the Kähler potential.

Effects of Wi-Fi (2.45 GHz) Exposure on Apoptosis, Sperm Parameters and Testicular Histomorphometry in Rats: A Time Course Study

PubMed Central

Shokri, Saeed; Soltani, Aiob; Kazemi, Mahsa; Sardari, Dariush; Mofrad, Farshid Babapoor

2015-01-01

Objective In today’s world, 2.45-GHz radio-frequency radiation (RFR) from industrial, scientific, medical, military and domestic applications is the main part of indoor-outdoor electromagnetic field exposure. Long-term effects of 2.45-GHz Wi-Fi radiation on male reproductive system was not known completely. Therefore, this study aimed to investigate the major cause of male infertility during short- and long-term exposure of Wi-Fi radiation. Materials and Methods This is an animal experimental study, which was conducted in the Department of Anatomical Sciences, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, IRAN, from June to August 2014. Three-month-old male Wistar rats (n=27) were exposed to the 2.45 GHz radiation in a chamber with two Wi-Fi antennas on opposite walls. Animals were divided into the three following groups: I. control group (n=9) including healthy animals without any exposure to the antenna, II. 1-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 1 hour per day during two months and III.7-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 7 hours per day during 2 months. Sperm parameters, caspase-3 concentrations, histomorphometric changes of testis in addition to the apoptotic indexes were evaluated in the exposed and control animals. Results Both 1-hour and 7-hour groups showed a decrease in sperm parameters in a time dependent pattern. In parallel, the number of apoptosis-positive cells and caspase-3 activity increased in the seminiferous tubules of exposed rats. The seminal vesicle weight reduced significantly in both1-hour or 7-hour groups in comparison to the control group. Conclusion Regarding to the progressive privilege of 2.45 GHz wireless networks in our environment, we concluded that there should be a major concern regarding the timedependent exposure of whole-body to the higher frequencies of Wi-Fi networks existing in the vicinity of our living places. PMID:26199911

Relation of Bowel Habits to Fecal Incontinence in Women

PubMed Central

Bharucha, Adil E.; Seide, Barbara M.; Zinsmeister, Alan R.; Melton, L. Joseph

2008-01-01

BACKGROUND Though most women with fecal incontinence (FI) have anorectal dysfunctions, a majority have intermittent symptoms. Variations in bowel habits and daily routine may partly explain this. AIM To compare bowel habits and daily routine between controls and FI, and between continent and incontinent stools among women with FI. METHOD Using a mailed questionnaire, we identified 507 women with FI among 5,300 women in Olmsted County, MN. Bowel habits were compared among 127 randomly selected controls and 154 women with self-reported FI, who did (“active” FI, N = 106) or did not (“inactive” FI, N = 48) have an incontinent episode during a 2-wk bowel diary period. RESULTS Independent risk factors for FI were: rectal urgency (odds ratio [OR] for inactive FI vs controls 5.6, 95% confidence interval [CI] 2.3–13.3; and OR for active FI vs inactive FI 2.0, 95% CI 0.9–4.3) and a sense of incomplete evacuation (OR for inactive FI vs controls 3.5, 95% CI 1.4–8.8; and OR for active FI vs inactive FI 2.2, 95% CI 1.1–4.9). Similar results were found for stool frequency and form. Among incontinent women, incontinent stools (versus continent stools) were less formed, more likely to occur at work, and to be preceded by rectal urgency. CONCLUSIONS Bowel patterns, rectal urgency, and daily routine influence the occurrence of FI. Stool characteristics explained 46% of the likelihood for incontinence episodes, emphasizing that anorectal sensorimotor dysfunctions must also contribute to FI in women. PMID:18510612

Effects of the magnetic field gradient on the wall power deposition of Hall thrusters

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Li, Peng; Zhang, Xu; Wei, Liqiu; Sun, Hezhi; Peng, Wuji; Yu, Daren

2017-04-01

The effect of the magnetic field gradient in the discharge channel of a Hall thruster on the ionization of the neutral gas and power deposition on the wall is studied through adopting the 2D-3V particle-in-cell (PIC) and Monte Carlo collisions (MCC) model. The research shows that by gradually increasing the magnetic field gradient while keeping the maximum magnetic intensity at the channel exit and the anode position unchanged, the ionization region moves towards the channel exit and then a second ionization region appears near the anode region. Meanwhile, power deposition on the walls decreases initially and then increases. To avoid power deposition on the walls produced by electrons and ions which are ionized in the second ionization region, the anode position is moved towards the channel exit as the magnetic field gradient is increased; when the anode position remains at the zero magnetic field position, power deposition on the walls decreases, which can effectively reduce the temperature and thermal load of the discharge channel.

Prebreakdown characteristics of weakly ionized liquid and gaseous media in the strongly nonuniform electric field

NASA Astrophysics Data System (ADS)

Apfelbaum, M. S.; Syrovatka, R. A.; Vladimirov, V. I.

2018-01-01

A theoretical model of electrohydrodynamic prebreakdown phenomena in slightly ionized (weakly conductive) media is proposed. The electric high voltage conduction of weakly conductive liquids and slightly ionized gases in intense electric fields using this model is considered. The formula for the calculations of volt-ampere characteristics under high voltage spherical capacitor field is analytically obtained. The experimental corona discharge volt-ampere characteristics of air are presented. It was found that the size of the ionization region in the case of corona discharge in air increases monotonically with increasing discharge voltage.

Coupled-cluster treatment of molecular strong-field ionization

NASA Astrophysics Data System (ADS)

Jagau, Thomas-C.

2018-05-01

Ionization rates and Stark shifts of H2, CO, O2, H2O, and CH4 in static electric fields have been computed with coupled-cluster methods in a basis set of atom-centered Gaussian functions with a complex-scaled exponent. Consideration of electron correlation is found to be of great importance even for a qualitatively correct description of the dependence of ionization rates and Stark shifts on the strength and orientation of the external field. The analysis of the second moments of the molecular charge distribution suggests a simple criterion for distinguishing tunnel and barrier suppression ionization in polyatomic molecules.

Selectivity of Electronic Coherence and Attosecond Ionization Delays in Strong-Field Double Ionization

NASA Astrophysics Data System (ADS)

Kobayashi, Yuki; Reduzzi, Maurizio; Chang, Kristina F.; Timmers, Henry; Neumark, Daniel M.; Leone, Stephen R.

2018-06-01

Experiments are presented on real-time probing of coherent electron dynamics in xenon initiated by strong-field double ionization. Attosecond transient absorption measurements allow for characterization of electronic coherences as well as relative ionization timings in multiple electronic states of Xe+ and Xe2 + . A high degree of coherence g =0.4 is observed between P3 2 0-P3 0 0 of Xe2 + , whereas for other possible pairs of states the coherences are below the detection limits of the experiments. A comparison of the experimental results with numerical simulations based on an uncorrelated electron-emission model shows that the coherences produced by strong-field double ionization are more selective than predicted. Surprisingly short ionization time delays, 0.85 fs, 0.64 fs, and 0.75 fs relative to Xe+ formation, are also measured for the P2 3 , P0 3 , and P1 3 states of Xe2 + , respectively. Both the unpredicted selectivity in the formation of coherence and the subfemtosecond time delays of specific states provide new insight into correlated electron dynamics in strong-field double ionization.

Control of embankment settlement field verification on PCPT prediction methods : tech summary.

DOT National Transportation Integrated Search

2011-07-01

Depending on loading and embankment height, the magnitude and progression of settlement can signifi cantly impact the safety and : serviceability of the infrastructures that are constructed on saturated fi ne-grained soils. Therefore, the constructio...

Relativistic Ionization with Intense Linearly Polarized Light

NASA Astrophysics Data System (ADS)

Crawford, Douglas Plummer

The Strong Field Approximation (SFA) method is used to derive relativistic ionization rate expressions for ground state hydrogen-like atoms in the presence of an intense electromagnetic field. The emitted particle, which is initially bound to a hydrogen nucleus, is either an electron described by the Dirac equation, with spin effects fully included, or a spinless "electron" described by the Klein-Gordon equation. The derivations and subsequent calculations for both particles are made assuming a linearly polarized electromagnetic field which is monochromatic and which exhibits neither diffraction nor temporal dependence. From each of the relativistic ionization rate expressions, the corresponding expression in the nonrelativistic limit is derived. The resultant expressions are found to be equivalent to those derived using the SFA with the nonrelativistic formalism. This comparison provides the first check of the validity for the core results of this dissertation. Intensity-dependent ionization rates are then calculated for two ultraviolet frequencies using a numerical implementation of the derived expressions. Calculations of ionization rates and related phenomena demonstrate that there are negligible differences between relativistic and nonrelativistic predictions for low intensities. In addition, the differences in behavior between linearly and circularly polarized ionizing fields and between particles with and without spin are explored. The spin comparisons provide additional confidence in the derivations by showing negligible differences between ionization rates for Dirac and Klein -Gordon particles in strong linearly-polarized fields. Also of interest are the differential transition rates which exhibit dynamic profiles as the intensity is increased. This behavior is interpreted as an indication of more atomic influence for linearly polarized electromagnetic (em) fields than for circularly polarized em fields.

Organic matter composition at intact biopore and crack surfaces of Luvisol B-horizons analyzed by FTIR spectroscopy and Pyrolysis-Field Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Leue, Martin; Eckhardt, Kai-Uwe; Ellerbrock, Ruth H.; Gerke, Horst H.; Leinweber, Peter

2015-04-01

In the B-horizons of Luvisols, surfaces of biopores and aggregates can be enriched in clay and organic matter (OM), relative to the bulk of the soil matrix. The OM composition of these coatings determines their bio-physico-chemical properties and is relevant for transport and transformation processes but is largely unknown at the molecular scale. The objective of this study was an extended characterization of the OM composition at intact biopore and aggregate surfaces. Specifically, we aimed to improve the interpretation of data obtained with Fourier transform infrared spectroscopy in diffuse reflectance mode (DRIFT) by combining the signals from DRIFT spectra with data from pyrolysis-field ionization mass spectrometry (Py-FIMS) as a more detailed molecular-scale analysis. Samples were manually separated from the outermost surfaces of earthworm burrows, coated and uncoated cracks, root channels, and pinhole fillings of the B-horizons of Luvisols developed from loess and glacial till. The OM at earthworm burrow walls was characterized by a mix of chemically labile aliphatic C-rich and more stable lignin and alkylaromatic compounds whereas the OM of coated cracks and pinholes was dominated by relatively stable heterocylic N and nitriles, and high-molecular aromatic compounds (benzonitrile and naphthalene). This more recalcitrant OM likely originated from the combustion of biomass and, in case of the till-derived Luvisol, from diesel exhausts. The OM composition of pore walls reflected the differences between biopores (i.e., topsoil and plant residual, worm activity) and cracks (i.e., solutes and colloids, rapid percolation). The information of Py-FI mass spectra enabled the assignment of OM functional groups also from spectral regions of overlapping DRIFT signal intensities to specific OM compound classes. In particular, bands from C=O and C=C bonds in the infrared range of wave number 1688 … 1565 cm-1 were related to highly stable, chemically recalcitrant OM components such as heterocyclic N-compounds, benzonitrile and naphthalene. Based on such relations, the OM composition at intact soil structural surfaces relevant for sorption and wettability could be characterized in more detail even by using DRIFT spectroscopy.

Local shear instabilities in weakly ionized, weakly magnetized disks

NASA Technical Reports Server (NTRS)

Blaes, Omer M.; Balbus, Steven A.

1994-01-01

We extend the analysis of axisymmetric magnetic shear instabilities from ideal magnetohydrodynamic (MHD) flows to weakly ionized plasmas with coupling between ions and neutrals caused by collisions, ionization, and recombination. As part of the analysis, we derive the single-fluid MHD dispersion relation without invoking the Boussinesq approximation. This work expands the range of applications of these instabilities from fully ionized accretion disks to molecular disks in galaxies and, with somewhat more uncertainty, to protostellar disks. Instability generally requires the angular velocity to decrease outward, the magnetic field strengths to be subthermal, and the ions and neutrals to be sufficiently well coupled. If ionization and recombination processes can be neglected on an orbital timescale, adequate coupling is achieved when the collision frequency of a given neutral with the ions exceeds the local epicyclic freqency. When ionization equilibrium is maintained on an orbital timescale, a new feature is present in the disk dynamics: in contrast to a single-fluid system, subthermal azimuthal fields can affect the axisymmetric stability of weakly ionized two-fluid systems. We discuss the underlying causes for this behavior. Azimuthal fields tend to be stabilizing under these circumstances, and good coupling between the neutrals and ions requires the collision frequency to exceed the epicyclic frequency by a potentially large secant factor related to the magnetic field geometry. When the instability is present, subthermal azimuthal fields may also reduce the growth rate unless the collision frequency is high, but this is important only if the field strengths are very subthermal and/or the azimuthal field is the dominant field component. We briefly discuss our results in the context of the Galactic center circumnuclear disk, and suggest that the shear instability might be present there, and be responsible for the observed turbulent motions.

Department of the Navy Fiscal Year (FY) 2000/2001 Biennial Budget Estimates, Justification of Estimates, February 1999 Research, Development, Test & Evaluation, Navy Budget Activity 6.

DTIC Science & Technology

1999-02-01

g o o rd-H S 4-1 O M o id o ■H fi u a-H CDrH •H tn Q H >i fc ftU ■H i tn O o g o a o) o „ fi-H Ä-0 - $ H * H 01 O H 4J 4J 0 u...CJ CO fi fi-H g E> Q \\ fi S fi 1 <D,fi T) CDrH ^ Id W rH CO * o • _ Q o H O fi co „, <" •H O 4-1 x! o> fi JJ (D a o 0 >H in i

Carrier-envelope phase-dependent ionization of Xe in intense, ultrafast (two-cycle) laser fields

NASA Astrophysics Data System (ADS)

Vasa, Parinda; Dharmadhikari, Aditya K.; Mathur, Deepak

2018-01-01

We report an experimental study that shows the dependence of the tunnel ionization of Xe by two-cycle, intense, near infrared light on the carrier-envelope-phase (CEP) of incident laser pulses. At low values of the optical field (E), the ionization yield is found to be maximum for cos-like pulses; the CEP dependence of the ion yield becomes stronger for higher charge states. At higher E-values, the CEP dependence either washes out or flips. A simple phenomenological model is used to confirm that our results fall within the ambit of the current understanding of ionization dynamics in strong, ultrashort optical fields. In the observed tunnel ionization of Xe, CEP effects appear to persist for longer, eight-cycle, pulses. Electron rescattering is observed to play a relatively unimportant role in the observed CEP dependence. These results provide fresh perspectives in the ionization mechanisms of multielectron systems in the few-cycle regime.

Fecal incontinence knowledge, attitudes, and help-seeking behaviors among community-dwelling adults in Korea.

PubMed

Joh, Hee-Kyung; Seong, Moo-Kyung; Ahn, Hyun-Jun

2018-04-01

Fecal incontinence (FI) is a common debilitating disorder that tends to be underreported. Although low health literacy likely contributes to the underreporting, studies on FI knowledge among the general population remain scarce. We investigated how FI knowledge is associated with attitudes and help-seeking behaviors. We conducted a cross-sectional survey among community-dwelling adults undergoing national health screening in Korea. A structured, self-administered questionnaire was used to assess FI knowledge, attitudes, and help-seeking behaviors. Odds ratios (ORs; 95% confidence intervals, CIs) were estimated using logistic regression with adjustment for covariables. Of the 601 participants completing the survey, only 29.8% were aware of the term FI, and their knowledge levels were insufficient. As for FI-related attitudes, 24.6% considered FI to be very rare, and 22.3% considered it to be moderately or less distressing. Individuals who knew the term FI tended to consider FI more common (OR: 2.45; 95%CI: 1.49-4.02) and distressing (OR: 1.68; 95%CI: 1.07-2.63) than those without knowledge. Assuming future FI occurrence, those considering FI to be distressing were less willing to ignore or self-manage the condition (OR: 0.25; 95%CI: 0.11-0.58). Among patients with FI (n = 83), only 30.1% had sought help and 8.4% had consulted doctors. Knowing the term FI was significantly associated with overall help-seeking behavior (OR: 9.23; 95%CI: 2.09-40.77). FI knowledge levels and help-seeking rates were low among community-dwelling adults. FI knowledge was significantly associated with attitudes and help-seeking behaviors. Future public education programs are warranted to improve FI knowledge, attitudes, and help-seeking behaviors. © 2018 Wiley Periodicals, Inc.

Examining Coherency Scales, Substructure, and Propagation of Whistler Mode Chorus Elements With Magnetospheric Multiscale (MMS)

NASA Astrophysics Data System (ADS)

Turner, D. L.; Lee, J. H.; Claudepierre, S. G.; Fennell, J. F.; Blake, J. B.; Jaynes, A. N.; Leonard, T.; Wilder, F. D.; Ergun, R. E.; Baker, D. N.; Cohen, I. J.; Mauk, B. H.; Strangeway, R. J.; Hartley, D. P.; Kletzing, C. A.; Breuillard, H.; Le Contel, O.; Khotyaintsev, Yu. V.; Torbert, R. B.; Allen, R. C.; Burch, J. L.; Santolik, O.

2017-11-01

Whistler mode chorus waves are a naturally occurring electromagnetic emission observed in Earth's magnetosphere. Here, for the first time, data from NASA's Magnetospheric Multiscale (MMS) mission were used to analyze chorus waves in detail, including the calculation of chorus wave normal vectors, fi>k. A case study was examined from a period of substorm activity around the time of a conjunction between the MMS constellation and NASA's Van Allen Probes mission on 07 April 2016. Chorus wave activity was simultaneously observed by all six spacecraft over a broad range of L shells (5.5 < L < 8.5), magnetic local time (06:00 < MLT < 09:00), and magnetic latitude (-32° < MLAT < -15°), implying a large chorus active region. Eight chorus elements and their substructure were analyzed in detail with MMS. These chorus elements were all lower band and rising tone emissions, right-handed and nearly circularly polarized, and propagating away from the magnetic equator when they were observed at MMS (MLAT -31°). Most of the elements had "hook"-like signatures on their wave power spectra, characterized by enhanced wave power at flat or falling frequency following the peak, and all the elements exhibited complex and well-organized substructure observed consistently at all four MMS spacecraft at separations up to 70 km (60 km perpendicular and 38 km parallel to the background magnetic field). The waveforms in field-aligned coordinates also demonstrated that these waves were all phase coherent, allowing for the direct calculation of fi>k. Error estimates on calculated fi>k revealed that the plane wave approximation was valid for six of the eight elements and most of the subelements. The wave normal vectors were within 20-30° from the direction antiparallel to the background field for all elements and changed from subelement to subelement through at least two of the eight elements. The azimuthal angle of fi>k in the perpendicular plane was oriented earthward and was oblique to that of the Poynting vector, which has implications for the validity of cold plasma theory.

A study of the security technology and a new security model for WiFi network

NASA Astrophysics Data System (ADS)

Huang, Jing

2013-07-01

The WiFi network is one of the most rapidly developing wireless communication networks, which makes wireless office and wireless life possible and greatly expands the application form and scope of the internet. At the same time, the WiFi network security has received wide attention, and this is also the key factor of WiFi network development. This paper makes a systematic introduction to the WiFi network and WiFi network security problems, and the WiFi network security technology are reviewed and compared. In order to solve the security problems in WiFi network, this paper presents a new WiFi network security model and the key exchange algorithm. Experiments are performed to test the performance of the model, the results show that the new security model can withstand external network attack and ensure stable and safe operation of WiFi network.

The inception of pulsed discharges in air: simulations in background fields above and below breakdown

NASA Astrophysics Data System (ADS)

Sun, Anbang; Teunissen, Jannis; Ebert, Ute

2014-11-01

We investigate discharge inception in air, in uniform background electric fields above and below the breakdown threshold. We perform 3D particle simulations that include a natural level of background ionization in the form of positive and \\text{O}2- ions. In background fields below breakdown, we use a strongly ionized seed of electrons and positive ions to enhance the field locally. In the region of enhanced field, we observe the growth of positive streamers, as in previous simulations with 2D plasma fluid models. The inclusion of background ionization has little effect in this case. When the background field is above the breakdown threshold, the situation is very different. Electrons can then detach from \\text{O}2- and start ionization avalanches in the whole volume. These avalanches together create one extended discharge, in contrast to the ‘double-headed’ streamers found in many fluid simulations.

The Effects of Students' Cognitive Styles on Conceptual Understandings and Problem-Solving Skills in Introductory Mechanics

ERIC Educational Resources Information Center

Ates, Salih; Cataloglu, Erdat

2007-01-01

The purpose of this study was to determine if there are relationships among freshmen students' Field depended or field independent (FD/FI) cognitive style, conceptual understandings, and problem solving skills in mechanics. The sample consisted of 213 freshmen (female = 111, male = 102; age range 17-21) who were enrolled in an introductory physics…

Foreign Language Achievement in Relation to Student-Teacher Cognitive Styles: A Preliminary Study.

ERIC Educational Resources Information Center

Hansen, Jacqueline; Stansfield, Charles

Research has shown student field-independent cognitive style (FI), as opposed to field-dependent cognitive style (FD), to be correlated moderately with success on selected second language tasks. A trait-treatment interaction approach was utilized in this study to examine the role of FD/I among 236 college students enrolled in six sections of an…

The Thinking Process Of Field Independent Cognitive Style Of Junior High School Student In Defining Quadrilateral Concept

NASA Astrophysics Data System (ADS)

Rahaju, E. B.

2018-01-01

Defining a quadrilateral concept is one part of mathematics learning in junior high school. Defining a concept can be influenced by the concept’s image. While the image of the concept is influenced by the experience associated with the concept, the characteristics of the concept, the mental picture of the concept, and the reconstruction of the definition made by the person against a concept. The thinking process of a person in defining a concept is influenced by cognitive style. This study aimed to describe the thinking process of a student in defining the quadrilateral concept based on her cognitive style. The subject of this research was a student on grade VII with Field Independent cognitive style (FI). This research concludes that the subject of FI in defining quadrilateral concepts, begins by forming a sense through listing the characteristics of quadrilateral. In determining the characteristics of a quadrilateral, subjects tend to organize all quadrilateral models that have been grouped. This suggests that the subject of FI is easier to capture the similarities found in the models that have been grouped. Based on the characteristics, the subject can conclude to make a simple definition of a quadrilateral by eliminating one by one characteristic are not essential. Subjects can make definitions that meet necessary and sufficient conditions on square, rectangular, parallelogram and trapezoid.

Analysis of algebraic reasoning ability of cognitive style perspectives on field dependent field independent and gender

NASA Astrophysics Data System (ADS)

Rosita, N. T.

2018-03-01

The purpose of this study is to analyse algebraic reasoning ability using the SOLO model as a theoretical framework to assess students’ algebraic reasoning abilities of Field Dependent cognitive (FD), Field Independent (FI) and Gender perspectives. The method of this study is a qualitative research. The instrument of this study is the researcher himself assisted with algebraic reasoning tests, the problems have been designed based on NCTM indicators and algebraic reasoning according to SOLO model. While the cognitive style of students is determined using Group Embedded Figure Test (GEFT), as well as interviews on the subject as triangulation. The subjects are 15 female and 15 males of the sixth semester students of mathematics education, STKIP Sebelas April. The results of the qualitative data analysis is that most subjects are at the level of unistructural and multi-structural, subjects at the relational level have difficulty in forming a new linear pattern. While the subjects at the extended abstract level are able to meet all the indicators of algebraic reasoning ability even though some of the answers are not perfect yet. Subjects of FI tend to have higher algebraic reasoning abilities than of the subject of FD.

Numerical analysis for infant's unintentional exposure to 3.5 GHz plane wave radiofrequency electromagnetic fields by field test of fifth generation wireless technologies

NASA Astrophysics Data System (ADS)

Liu, Dan; Li, Congsheng; Kang, Yangyang; Zhou, Zhou; Xie, Yi; Wu, Tongning

2017-09-01

In this study, the plane wave exposure of an infant to radiofrequency electromagnetic fields of 3.5 GHz was numerically analyzed to investigate the unintentional electromagnetic field (EMF) exposure of fifth generation (5G) signals during field test. The dosimetric influence of age-dependent dielectric properties and the influence of an adult body were evaluated using an infant model of 12 month old and an adult female model. The results demonstrated that the whole body-averaged specific absorption rate (WBASAR) was not significantly affected by age-dependent dielectric properties and the influence of the adult body did not enhance WBASAR. Taking the magnitude of the in situ E field strength into consideration, realistic WBASAR was far below the basic restriction. Age-dependent dielectric properties could significantly change the tissue specified specific absorption rate (TSSAR) of internal organs. However, the variation was not significant because the absolute values were marginal. Among the factors that influenced TSSAR variation, change in dielectric properties demonstrated a close correlation. In general, at 3.5 GHz, the infant did not absorb more power than the case of EMF exposure to third generation (3G) and fourth generation (4G) signals. The work was helpful for network operators and device manufactures to estimate the potential exposure risk during the field test, especially for the infant.

Acadia National Park ITS field operational test : evaluation strategic plan

DOT National Transportation Integrated Search

2000-07-01

This document provides a strategy for evaluating technologies known as Intelligent Transportation Systems (ITS) that will be implemented in Acadia National Park and Mount Desert Island, Maine. Acadia National Park was selected as a site for an ITS Fi...

Mechanisms of two-color laser-induced field-free molecular orientation.

PubMed

Spanner, Michael; Patchkovskii, Serguei; Frumker, Eugene; Corkum, Paul

2012-09-14

Two mechanisms of two-color (ω+2ω) laser-induced field-free molecular orientation, based on the hyperpolarizability and ionization depletion, are explored and compared. The CO molecule is used as a computational example. While the hyperpolarizability mechanism generates small amounts of orientation at intensities below the ionization threshold, ionization depletion quickly becomes the dominant mechanism as soon as ionizing intensities are reached. Only the ionization mechanism leads to substantial orientation (e.g., on the order of ≳0.1). For intensities typical of laser-induced molecular alignment and orientation experiments, the two mechanisms lead to robust, characteristic timings of the field-free orientation wave-packet revivals relative to the alignment revivals and the revival time. The revival timings can be used to detect the active orientation mechanism experimentally.

Sequential and direct ionic excitation in the strong-field ionization of 1-butene molecules.

PubMed

Schell, Felix; Boguslavskiy, Andrey E; Schulz, Claus Peter; Patchkovskii, Serguei; Vrakking, Marc J J; Stolow, Albert; Mikosch, Jochen

2018-05-18

We study the Strong-Field Ionization (SFI) of the hydrocarbon 1-butene as a function of wavelength using photoion-photoelectron covariance and coincidence spectroscopy. We observe a striking transition in the fragment-associated photoelectron spectra: from a single Above Threshold Ionization (ATI) progression for photon energies less than the cation D0-D1 gap to two ATI progressions for a photon energy greater than this gap. For the first case, electronically excited cations are created by SFI populating the ground cationic state D0, followed by sequential post-ionization excitation. For the second case, direct sub-cycle SFI to the D1 excited cation state contributes significantly. Our experiments access ionization dynamics in a regime where strong-field and resonance-enhanced processes can interplay.

Optimizing the 391-nm lasing intensity from ionized nitrogen molecules in 800-nm femtosecond laser fields

NASA Astrophysics Data System (ADS)

Zhong, Xunqi; Miao, Zhiming; Zhang, Linlin; Jiang, Hongbing; Liu, Yunquan; Gong, Qihuang; Wu, Chengyin

2018-03-01

We investigate the 391-nm lasing dynamics from ionized nitrogen molecules in 800-nm femtosecond laser fields. By comparing the radiation intensity, spectrum shape, and temporal profile of the 391-nm lasing at various experimental conditions, we conclude that the lasing dynamics contains not only the generation and the decay of ionized nitrogen molecules, but also the seed-built coherence among emitters as well as the propagation effect in the plasma filamentation. These results provide reliable guidance for optimizing the 391-nm lasing from ionized nitrogen molecules in 800-nm femtosecond laser fields, which have potential applications for remote sensing in the atmosphere.

The Technology of LiFi: A Brief Introduction

NASA Astrophysics Data System (ADS)

Ramadhani, E.; Mahardika, G. P.

2018-03-01

Light Fidelity (LiFi) is a Visible Light Communication (VLC) based technology that making a light as a media of communication replacing the cable wire communication. LiFi is evolve to overcome the rate speed in WiFi, while using LiFi the rate speed can reach until 14 Gbps. This paper presents an introduction of the LiFi technology including the architecture, modulation, performance, and the challenges. The result of this paper can be used as a reference and knowledge to develop some of the LiFi technology.

Directed Field Ionization: A Genetic Algorithm for Evolving Electric Field Pulses

NASA Astrophysics Data System (ADS)

Kang, Xinyue; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.

2017-04-01

When an ionizing electric field pulse is applied to a Rydberg atom, the electron's amplitude traverses many avoided crossings among the Stark levels as the field increases. The resulting superposition determines the shape of the time resolved field ionization spectrum at a detector. An engineered electric field pulse that sweeps back and forth through avoided crossings can control the phase evolution so as to determine the electron's path through the Stark map. In the region of n = 35 in rubidium there are hundreds of potential avoided crossings; this yields a large space of possible pulses. We use a genetic algorithm to search this space and evolve electric field pulses to direct the ionization of the Rydberg electron in rubidium. We present the algorithm along with a comparison of simulated and experimental results. This work was supported by the National Science Foundation under Grants No. 1607335 and No. 1607377 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number OCI-1053575.

Identifying the Tunneling Site in Strong-Field Ionization of H_{2}^{+}.

PubMed

Liu, Kunlong; Barth, Ingo

2017-12-15

The tunneling site of the electron in a molecule exposed to a strong laser field determines the initial position of the ionizing electron and, as a result, has a large impact on the subsequent ultrafast electron dynamics on the polyatomic Coulomb potential. Here, the tunneling site of the electron of H_{2}^{+} ionized by a strong circularly polarized (CP) laser pulse is studied by numerically solving the time-dependent Schrödinger equation. We show that the electron removed from the down-field site is directly driven away by the CP field and the lateral photoelectron momentum distribution (LPMD) exhibits a Gaussian-like distribution, whereas the corresponding LPMD of the electron removed from the up-field site differs from the Gaussian shape due to the Coulomb focusing and scattering by the down-field core. Our current study presents the direct evidence clarifying a long-standing controversy over the tunneling site in H_{2}^{+} and raises the important role of the tunneling site in strong-field molecular ionization.

Eclogitization of the Subducted Oceanic Crust and Its Implications for the Mechanism of Slow Earthquakes

NASA Astrophysics Data System (ADS)

Wang, Xinyang; Zhao, Dapeng; Suzuki, Haruhiko; Li, Jiabiao; Ruan, Aiguo

2017-12-01

The generating mechanism and process of slow earthquakes can help us to better understand the seismogenic process and the petrological evolution of the subduction system, but they are still not very clear. In this work we present robust P and S wave tomography and Poisson's ratio images of the subducting Philippine Sea Plate beneath the Kii peninsula in Southwest Japan. Our results clearly reveal the spatial extent and variation of a low-velocity and high Poisson's ratio layer which is interpreted as the remnant of the subducted oceanic crust. The low-velocity layer disappears at depths >50 km, which is attributed to crustal eclogitization and consumption of fluids. The crustal eclogitization and destruction of the impermeable seal play a key role in the generation of slow earthquakes. The Moho depth of the overlying plate is an important factor affecting the depth range of slow earthquakes in warm subduction zones due to the transition of interface permeability from low to high there. The possible mechanism of the deep slow earthquakes is the dehydrated oceanic crustal rupture and shear slip at the transition zone in response to the crustal eclogitization and the temporal stress/strain field. A potential cause of the slow event gap existing beneath easternmost Shikoku and the Kii channel is the premature rupture of the subducted oceanic crust due to the large tensional force.

Impact of the semidiurnal lunar tide on the midlatitude thermospheric wind and ionosphere during sudden stratosphere warmings

NASA Astrophysics Data System (ADS)

Pedatella, N. M.; Maute, A.

2015-12-01

Variability of the midlatitude ionosphere and thermosphere during the 2009 and 2013 sudden stratosphere warmings (SSWs) is investigated in the present study using a combination of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations and thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) simulations. Both the COSMIC observations and TIME-GCM simulations reveal perturbations in the F region peak height (hmF2) at Southern Hemisphere midlatitudes during SSW time periods. The perturbations are ˜20-30 km, which corresponds to 10-20% variability of the background mean hmF2. The TIME-GCM simulations and COSMIC observations of the hmF2 variability are in overall good agreement, and the simulations can thus be used to understand the physical processes responsible for the hmF2 variability. Through comparison of simulations with and without the migrating semidiurnal lunar tide (M2), we conclude that the midlatitude hmF2 variability is primarily driven by the propagation of the M2 into the thermosphere where it modulates the field-aligned neutral winds, which in turn raise and lower the F region peak height. Though there are subtle differences, the consistency of the behavior between the 2009 and 2013 SSWs suggests that variability in the Southern Hemisphere midlatitude ionosphere and thermosphere is a consistent feature of the SSW impact on the upper atmosphere.

Strong-field ionization of H{sub 2} from ultraviolet to near-infrared wavelengths: Photoelectron energy and angular identifications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilbois, Timo; Helm, Hanspeter

2011-11-15

Strong-field ionization of molecular hydrogen is studied at wavelengths ranging from 300 to 800 nm using pulses of 100-fs duration. We find that over this wide wavelength range, from nominally 4-photon to 11-photon ionization, resonance features dominate the ionization probability at intensities below 10{sup 14} W/cm{sup 2}. Photoelectron momentum maps recorded by an imaging spectrometer are analyzed to identify the wavelength-dependent ionization pathways in single ionization of molecular hydrogen. A number of models, some empirical, which are appropriate for a quantitative interpretation of the spectra and the ionization yield are introduced. A near-absolute comparison of measured ionization yields at 398more » nm is made with the predictions based on a numerical solution [Y. V. Vanne and A. Saenz, Phys. Rev. A 79, 023421 (2009)] of the time-dependent Schroedinger equation for two correlated electrons.« less

The alanine detector in BNCT dosimetry: Dose response in thermal and epithermal neutron fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitz, T., E-mail: schmito@uni-mainz.de; Bassler, N.; Blaickner, M.

Purpose: The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different neutron beams to explore the alanine dose response behavior and to validate model predictions. Additionally, application in medical neutron fields for boron neutron capture therapy is discussed. Methods: Alanine detectors have been irradiated in the thermal neutron field of the research reactor TRIGA Mainz, Germany, in five experimental conditions, generating different secondary particlemore » spectra. Further irradiations have been made in the epithermal neutron beams at the research reactors FiR 1 in Helsinki, Finland, and Tsing Hua open pool reactor in HsinChu, Taiwan ROC. Readout has been performed with electron spin resonance spectrometry with reference to an absorbed dose standard in a {sup 60}Co gamma ray beam. Absorbed doses and dose components have been calculated using the Monte Carlo codes FLUKA and MCNP. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using the Hansen and Olsen alanine response model. Results: The measured dose response of the alanine detector in the different experiments has been evaluated and compared to model predictions. Therefore, a relative effectiveness has been calculated for each dose component, accounting for its dependence on particle type and energy. Agreement within 5% between model and measurement has been achieved for most irradiated detectors. Significant differences have been observed in response behavior between thermal and epithermal neutron fields, especially regarding dose composition and depth dose curves. The calculated dose components could be verified with the experimental results in the different primary and secondary particle fields. Conclusions: The alanine detector can be used without difficulty in neutron fields. The response has been understood with the model used which includes the relative effectiveness. Results and the corresponding discussion lead to the conclusion that application in neutron fields for medical purpose is limited by its sensitivity but that it is a useful tool as supplement to other detectors and verification of neutron source descriptions.« less

Final Technical Report for DOE DE-FG02-05ER54831 "Laboratory Studies of Dynamos."

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forest, Cary B.

Laboratory Studies of Dynamos: Executive Summary. The self-generation of magnetic fields by astrophysical bodies like planets, stars, accretion disks, galaxies, and even galaxy clusters arises due to a mechanism referred to as a homogeneous dynamo. It is quite simple to demonstrate the generation of a magnetic fi eld from a rotating copper disk coupled with a coil of wire, a device known as the homopolar dynamo. The device works like a magnetic fi eld ampli er with a feedback circuit: the differential rotation of a metal disk past an infinitesimally small seed magnetic field induces currents in the disk which,more » when coupled to a coil winding, can amplify the field until it becomes strong enough to slow the rotation of the disk. What is remarkable is that the same type of circuit may be achieved in a flowing conducting fluid such as a liquid metal in the case of planetary dynamos or a plasma in the case of astrophysical dynamos. The complexity of describing planetary and stellar dynamos despite their ubiquity and the plethora of observational data from the Earth and the Sun motivates the demonstration of a laboratory homogenous dynamo. To create a homogenous dynamo, one first needs a su fficiently large, fast flow of a highly conducting fluid that the velocity shear in the fluid can bend magnetic field lines. With a high Rm-flow, the magnetic fi eld can be ampli ed by the stretching action provided by di fferential rotation. The other critical ingredient is a flow geometry that provides feedback so that the ampli ed eld reinforces the initial in nitesimal seed field - a mechanism that recreates the feedback provided by the coil of wire in the homopolar dynamo. In the Madison Dynamo Experiment, this combination of magnetic ampli cation and feedback is feasible in the simple geometry of two counter-rotating helical vortices in a 1 meter-diameter spherical vessel lled with liquid sodium. For an optimal helical pitch of the flow the threshold for exciting a dynamo is predicted from laminar flow modeling to be at peak flow speeds of 5 m/s. Liquid metals tend to have viscosities similar to that of water yielding inviscid flows. Whereas the timescale for the dynamo instability is on the resistive dissipation time, the timescale for hydrodynamic instability of the shear layer is quite short meaning that the shear layer required to generate the magnetic eld is broken up by Kelvin-Helmholtz instabilities. The eddies generated by large-scale flow drive instabilities at progressively smaller scale giving rise to a cascade of turbulent eddies driven at the largest scale of the experiment. The major contribution of the Madison Dynamo Experiment has been quantifying the role this turbulence plays in the generation of magnetic elds. Overall, the Madison Dynamo Experiment has now operated for about 1 decade and carried out experiments related to magnetic fi eld generation by turbulent flows of liquid metal. The principle thrust of research and indeed the main scienti fic outcomes are related to how turbulent flows create and transport magnetic fi elds.« less

Field Evaluation of Innovative Wastewater Collection System Condition Assessment Technologies

EPA Science Inventory

As part of an effort to address aging infrastructure needs, the U.S. Environmental Protection Agency (USEPA) initiated research under the Aging Water Infrastructure program, part of the USEPA Office of Water’s Sustainable Infrastructure Initiative. This presentation discusses fi...

ENVIRONMENTAL CARCINOGENESIS IN THE MUMMICHOG, FUNDULUS HETEROCLITUS: FIELD AND LABORATORY INVESTIGATIONS

EPA Science Inventory

The mummichog, Fundulus heteroclitus, is a small estuarine teleost inhabiting coastal embayments along much of the eastern seaboard of the US. We have been investigating an association between chemical contaminant exposure and adverse health impacts in this small cyprinodontid fi...

The Effects of Cognitive Styles on Naïve Impetus Theory Application Degrees of Pre-Service Science Teachers

ERIC Educational Resources Information Center

Cataloglu, Erdat; Ates, Salih

2014-01-01

The purpose of this study was to determine whether there is a relationship between pre-service science teachers' Field Dependent or Field Independent (FD/FI) cognitive styles and the application of degrees of naive impetus theory. The sample consisted of 122 pre-service science teachers (97 females and 25 males) who were enrolled in the…

Partially ionized hydrogen plasma in strong magnetic fields.

PubMed

Potekhin, A Y; Chabrier, G; Shibanov, Y A

1999-08-01

We study the thermodynamic properties of a partially ionized hydrogen plasma in strong magnetic fields, B approximately 10(12)-10(13) G, typical of neutron stars. The properties of the plasma depend significantly on the quantum-mechanical sizes and binding energies of the atoms, which are strongly modified by thermal motion across the field. We use new fitting formulas for the atomic binding energies and sizes, based on accurate numerical calculations and valid for any state of motion of the atom. In particular, we take into account decentered atomic states, neglected in previous studies of thermodynamics of magnetized plasmas. We also employ analytic fits for the thermodynamic functions of nonideal fully ionized electron-ion Coulomb plasmas. This enables us to construct an analytic model of the free energy. An ionization equilibrium equation is derived, taking into account the strong magnetic field effects and the nonideality effects. This equation is solved by an iteration technique. Ionization degrees, occupancies, and the equation of state are calculated.

Ion Densities in the Nightside Ionosphere of Mars: Effects of Electron Impact Ionization

NASA Astrophysics Data System (ADS)

Girazian, Z.; Mahaffy, P.; Lillis, R. J.; Benna, M.; Elrod, M.; Fowler, C. M.; Mitchell, D. L.

2017-11-01

We use observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to show how superthermal electron fluxes and crustal magnetic fields affect ion densities in the nightside ionosphere of Mars. We find that due to electron impact ionization, high electron fluxes significantly increase the CO2+, O+, and O2+ densities below 200 km but only modestly increase the NO+ density. High electron fluxes also produce distinct peaks in the CO2+, O+, and O2+ altitude profiles. We also find that superthermal electron fluxes are smaller near strong crustal magnetic fields. Consequently, nightside ion densities are also smaller near strong crustal fields because they decay without being replenished by electron impact ionization. Furthermore, the NO+/O2+ ratio is enhanced near strong crustal fields because, in the absence of electron impact ionization, O2+ is converted into NO+ and not replenished. Our results show that electron impact ionization is a significant source of CO2+, O+, and O2+ in the nightside ionosphere of Mars.

Tunneling ionization and Wigner transform diagnostics in OSIRIS

NASA Astrophysics Data System (ADS)

Martins, S.; Fonseca, R. A.; Silva, L. O.; Deng, S.; Katsouleas, T.; Tsung, F.; Mori, W. B.

2004-11-01

We describe the ionization module implemented in the PIC code OSIRIS [1]. Benchmarks with previously published tunnel ionization results were made. Our ionization module works in 1D, 2D and 3D simulations with barrier suppression ionization or the ADK ionization model, and allows for moving ions. Several illustrative 3D numerical simulations were performed, namely of the propagation of a SLAC beam in a Li gas cell, for the parameters of [2]. We compare the performance of OSIRIS with/without the ionization module, concluding that much less simulation time is usually required when using the ionization module. A novel diagnostic over the electric field is implemented, the Wigner transform, that provides information on the local spectral content of the field. This diagnostic is applied to the analysis of the chirp induced in an ionizing laser pulse. [1] R. A. Fonseca et al., LNCS 2331, 342-351, (Springer, Heidelberg, 2002). [2] S. Deng et al., Phys. Rev. E 68, 047401 (2003).

Dosimetry for Small and Nonstandard Fields

NASA Astrophysics Data System (ADS)

Junell, Stephanie L.

The proposed small and non-standard field dosimetry protocol from the joint International Atomic Energy Agency (IAEA) and American Association of Physicist in Medicine working group introduces new reference field conditions for ionization chamber based reference dosimetry. Absorbed dose beam quality conversion factors (kQ factors) corresponding to this formalism were determined for three different models of ionization chambers: a Farmer-type ionization chamber, a thimble ionization chamber, and a small volume ionization chamber. Beam quality correction factor measurements were made in a specially developed cylindrical polymethyl methacrylate (PMMA) phantom and a water phantom using thermoluminescent dosimeters (TLDs) and alanine dosimeters to determine dose to water. The TLD system for absorbed dose to water determination in high energy photon and electron beams was fully characterized as part of this dissertation. The behavior of the beam quality correction factor was observed as it transfers the calibration coefficient from the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) 60Co reference beam to the small field calibration conditions of the small field formalism. TLD-determined beam quality correction factors for the calibration conditions investigated ranged from 0.97 to 1.30 and had associated standard deviations from 1% to 3%. The alanine-determined beam quality correction factors ranged from 0.996 to 1.293. Volume averaging effects were observed with the Farmer-type ionization chamber in the small static field conditions. The proposed small and non-standard field dosimetry protocols new composite-field reference condition demonstrated its potential to reduce or remove ionization chamber volume dependancies, but the measured beam quality correction factors were not equal to the standard CoP's kQ, indicating a change in beam quality in the small and non-standard field dosimetry protocols new composite-field reference condition relative to the standard broad beam reference conditions. The TLD- and alanine-determined beam quality correction factors in the composite-field reference conditions were approximately 3% greater and differed by more than one standard deviation from the published TG-51 kQ values for all three chambers.

Antigen-induced inhibition of autoimmune response to rat male accessory glands: distinct characteristics of I-A- and I-E-positive peritoneal cells.

PubMed

Rivero, V E; Ferro, M E; Romero-Piffiguer, M; Correa, S; Yranzo-Volonté, N; Riera, C M

1991-05-01

The present report describes different aspects of two populations of peritoneal cells (PC) obtained from rats injected i.p. 2 h or 24 h previously with a suppressor dose of a purified fraction (FI) of rat male accessory glands (RAG) (FI-PC2h and FI-PC24h, respectively). The FI-PC2h, which are mainly I-E (OX17) positive and can suppress the autoimmune response to RAG autoantigens, have an elevated phagocytic activity against Candida albicans and capacity to reduce the dye nitroblue tetrazolium. In contrast, FI-PC24h, which are mainly I-A (OX6) positive and can potentiate the autoimmunity to RAG autoantigens, have a diminished capacity to reduce the dye and a diminished phagocytic activity. Moreover, the Toxoplasma gondii appear to have a different effect on both populations. The parasites can invade FI-PC2h while FI-PC24h offer resistance to T. gondii aggression. FI-PC2h cultured during 22 h (FI-PC2-24h in vitro), or PC obtained from syngeneic recipients injected i.p. 22 h previously with FI-PC2h (FI-PC2-24h in vivo) show, as FI-PC2h, an increase of the I-E+ cells and capacity to induce suppression of the delayed-type hypersensitivity response to RAG autoantigens when they are injected to syngeneic rats 10 and 3 days prior to the immunization with chemically modified (diazotized arsanilic and sulfanilic acid) RAG in complete Freund's adjuvant. The PC obtained 24 h after injection of irradiated rats with N-PC plus FI show an increase of I-E+ cells whereas an enhancement of I-A+ cells can be observed when the PC are obtained 24 h after injection of irradiated and bone marrow-reconstituted rats with N-PC plus FI. These findings appear to indicate that FI-PC2h and FI-PC24h are functionally different and that the population obtained 24 h after injection of FI of RAG could not originate from either the population present 2 h after injection of FI of RAG injection nor from normal PC. They appear to require bone marrow precursors.

Food Insecurity and Mental Health Status: A Global Analysis of 149 Countries.

PubMed

Jones, Andrew D

2017-08-01

This study sought to determine the association of individual-level food insecurity (FI) with mental health status across all global regions. Cross-sectional data were analyzed in 2016 from the 2014 Gallup World Poll, a series of globally implemented, nationally representative surveys. FI was assessed using the Food Insecurity Experience Scale Survey Module for Individuals, an eight-question psychometric scale reporting individuals' experiences of FI. Individual-level composite indices of mental health, the Negative Experience Index and Positive Experience Index (0-100 scale), were calculated based on responses to five questions of respondents' recent negative and positive experiences, respectively, associated with depression and mental distress. The prevalence of any FI ranged from 18.3% in East Asia to 76.1% in Sub-Saharan Africa. In global analyses (149 countries) using adjusted multiple regression analyses, FI was associated in a dose-response fashion with poorer scores on the mental health indices (coefficient [95% CI]: Negative Experience Index: mild FI, 10.4 [9.5, 11.2]; moderate FI, 17.7 [16.4, 19.0]; severe FI, 24.5 [22.7, 26.3]; Positive Experience Index: mild FI, -8.3 [-9.3, -7.4]; moderate FI, -12.6 [-13.8, -11.3]; severe FI, -16.2 [-17.9, -14.5]). Within-region analyses (11 regions) consistently demonstrated the same trends. FI is associated with poorer mental health and specific psychosocial stressors across global regions independent of SES. The numerous pathways via which FI may contribute to common mental disorders, and the broad social implications of FI linked to cultural norms and self-efficacy, may contribute to the cross-cultural consistency of the findings. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Diet and Eating Pattern Modifications Used by Community Living Adults to Manage Their Fecal Incontinence

PubMed Central

Croswell, Emily; Bliss, Donna Z.; Savik, Kay

2010-01-01

Purpose The study aimed to describe modifications in diet and eating patterns made by community-living people to manage fecal incontinence (FI) and to compare these differences according to sex, age, and FI severity. Subjects and Setting Subjects were 188 community-living adults (77% female, 92% white, 34% ≥ 65 years of age) in the upper Midwest who participated in a study about managing FI with dietary fiber. Methods Subjects were interviewed about diet and eating pattern changes that they made to manage FI and self reported demographic data. FI severity was recorded daily. Results Fifty-five percent of participants perceived that some foods worsen their FI (e.g., fatty or spicy foods and dairy products). More women than men (40 vs 18%, p=.008) reported avoiding foods in order to manage FI. A greater percentage of younger than older people believed that fatty/greasy foods (15% vs. 4%,) and alcohol (14% vs. 3%,) worsened their FI. Subjects with a higher FI severity score appeared to wait until FI was more severe before restricting caffeine than those with lower severity scores (22.2 ± 9.8 vs 11.69 ± 8.3, p = .034). One-third of subjects consumed foods rich in dietary fiber to prevent FI. Subjects also reported altered eating or cooking patterns; skipping meals, or eating at consistent times to manage FI. Conclusions Diet modification for managing FI incorporates involves restriction of some foods, along with adding others foods to the diet. Nursing assessments of self-care practices for FI should include diet and eating pattern changes when developing a plan of care. PMID:21076267

Recollision induced excitation-ionization with counter-rotating two-color circularly polarized laser field

NASA Astrophysics Data System (ADS)

Ben, Shuai; Guo, Pei-Ying; Pan, Xue-Fei; Xu, Tong-Tong; Song, Kai-Li; Liu, Xue-Shen

2017-07-01

Nonsequential double ionization of Ar by a counter-rotating two-color circularly polarized laser field is theoretically investigated. At the combined intensity in the "knee" structure range, the double ionization occurs mainly through recollision induced excitation followed by subsequent ionization of Ar+∗ . By tracing the history of the recollision trajectories, we explain how the relative intensity ratio of the two colors controls the correlated electron dynamics and optimizes the ionization yields. The major channels contributing to enhancing the double ionization are through the elliptical trajectories with smaller travel time but not through the triangle shape or the other long cycle trajectories. Furthermore, the correlated electron dynamics could be limited to the attosecond time scale by adjusting the relative intensity ratio. Finally, the double ionization from doubly excited complex at low laser intensity is qualitatively discussed.

Gas dispersal potential of infant bedding of sudden death cases (II): Mathematical simulation of O2 deprivation around the face of infant mannequin model.

PubMed

Sakai, Jun; Takahashi, Shirushi; Funayama, Masato

2009-04-01

We assessed O(2) gas deprivation potential of bedding that had actually been used by 26 infants diagnosed with sudden unexpected infant death using FiCO(2) time course of baby mannequin model. All cases were the same ones in our poster paper (I). Mathematically, time-FiCO(2) (t) graphs were given as FiCO(2) (t)=C(1-e(Dt)). Here, "C" approximates the maximum FiCO(2) value, while "D" is the velocity to reach maximum FiCO(2). FiO(2) in a potential space around the mannequin's nares was estimated using a formula: FiO(2)=0.21-FiCO(2)/RQ. RQ is the respiratory quotient, and the normal human value is 0.8. The graph pattern of FiO(2) is roughly the inverse of the FiCO(2) time course. Four cases showed the bottom of estimated FiO(2) to be more than 15%, 15 were 15-6%, and the other seven were 6% or less. Considering the minimal tissue stores of O(2), changes in FiO(2) may be affected by both CO(2) production and gas movement around the infant's face. Especially, the latter seven cases may suggest the participation of the role not only of CO(2) accumulation but also of the decrease of O(2) around the face.

First-principles prediction of Si-doped Fe carbide as one of the possible constituents of Earth's inner core

NASA Astrophysics Data System (ADS)

Das, Tilak; Chatterjee, Swastika; Ghosh, Sujoy; Saha-Dasgupta, Tanusri

2017-09-01

We perform a computational study based on first-principles calculations to investigate the relative stability and elastic properties of the doped and undoped Fe carbide compounds at 200-364 GPa. We find that upon doping a few weight percent of Si impurities at the carbon sites in Fe7C3 carbide phases, the values of Poisson's ratio and density increase while VP, and VS decrease compared to their undoped counterparts. This leads to marked improvement in the agreement of seismic parameters such as P wave and S wave velocity, Poisson's ratio, and density with the Preliminary Reference Earth Model (PREM) data. The agreement with PREM data is found to be better for the orthorhombic phase of iron carbide (o-Fe7C3) compared to hexagonal phase (h-Fe7C3). Our theoretical analysis indicates that Fe carbide containing Si impurities can be a possible constituent of the Earth's inner core. Since the density of undoped Fe7C3 is low compared to that of inner core, as discussed in a recent theoretical study, our proposal of Si-doped Fe7C3 can provide an alternative solution as an important component of the Earth's inner core.

Sexual behaviour and sexual and reproductive health education: a cross-sectional study in Romania.

PubMed

Rada, Cornelia

2014-06-23

Up-to-date, genuine sexual and reproductive health (SRH) education programmes have been possible in Romania only since communism collapsed in 1990. Since 2006, Romania has had no national strategy in this field. Under current global circumstances (high labour mobility, internationally mixed marriages), issues previously considered solely national have become worldwide concerns. In 2011-2012, 1215 respondents homogeneously distributed on background, gender, educational level and age group (18-74) were sampled. This article uses a 96-item questionnaire about family and SRH, presenting results on nine items: first intercourse (FI), virginity, knowing first sexual partner, safe sex, number of sexual partners and sexual education. The data were analysed using Pearson chi-square tests and latent class analysis. Some participants (7.2%) engaged in FI at age 15 or earlier. The average age at FI was lower for men (18.08), for individuals with a lower education level (18.07) and for those in rural areas (18.27), compared with that for women, those with more education and those in urban areas, respectively. The average age at FI was over 2.5 years lower for people aged 18-24 (16.99) than for those aged 60-74 (p < 0.001). More than 60% were not married or partnered with their FI partner, and 17.8% engaged in FI less than a month after meeting their partner. Less than one-fourth practiced safe sex at FI, with higher proportions for the urban sample, those with an average level of education and those aged 18-35 (p < 0.001). Higher average numbers of sexual partners were found among men (6.56, compared with 2.37 among women), in urban areas (5.07, compared with 3.75 in rural areas) and among those with higher levels of education (p < 0.005). On average, subjects first received information on SRH at 15.39 years of age, with only 10% listing the school, doctors or medics as a source. Unsafe sex, early initiation of sexual activity and poor SRH education from schools, experts and parents require a multidisciplinary approach within prevention programmes, especially among the populations at risk: rural residents, those with low levels of education and youth.

Sexual behaviour and sexual and reproductive health education: a cross-sectional study in Romania

PubMed Central

2014-01-01

Background Up-to-date, genuine sexual and reproductive health (SRH) education programmes have been possible in Romania only since communism collapsed in 1990. Since 2006, Romania has had no national strategy in this field. Under current global circumstances (high labour mobility, internationally mixed marriages), issues previously considered solely national have become worldwide concerns. Methods In 2011–2012, 1215 respondents homogeneously distributed on background, gender, educational level and age group (18–74) were sampled. This article uses a 96-item questionnaire about family and SRH, presenting results on nine items: first intercourse (FI), virginity, knowing first sexual partner, safe sex, number of sexual partners and sexual education. The data were analysed using Pearson chi-square tests and latent class analysis. Results Some participants (7.2%) engaged in FI at age 15 or earlier. The average age at FI was lower for men (18.08), for individuals with a lower education level (18.07) and for those in rural areas (18.27), compared with that for women, those with more education and those in urban areas, respectively. The average age at FI was over 2.5 years lower for people aged 18–24 (16.99) than for those aged 60–74 (p < 0.001). More than 60% were not married or partnered with their FI partner, and 17.8% engaged in FI less than a month after meeting their partner. Less than one-fourth practiced safe sex at FI, with higher proportions for the urban sample, those with an average level of education and those aged 18–35 (p < 0.001). Higher average numbers of sexual partners were found among men (6.56, compared with 2.37 among women), in urban areas (5.07, compared with 3.75 in rural areas) and among those with higher levels of education (p < 0.005). On average, subjects first received information on SRH at 15.39 years of age, with only 10% listing the school, doctors or medics as a source. Conclusions Unsafe sex, early initiation of sexual activity and poor SRH education from schools, experts and parents require a multidisciplinary approach within prevention programmes, especially among the populations at risk: rural residents, those with low levels of education and youth. PMID:24957900

The X-ray evolution of inflows and outflows in active galactic nuclei

NASA Astrophysics Data System (ADS)

Saez, Cristian

The evolution of the space density of AGNs might have spectral counterparts which could be observable in X-rays. The main objective of this thesis is to study the spectral properties of AGNs in X-rays in order to increase our current knowledge of AGN evolution. In chapter 2, we present results from a statistical analysis of 173 bright radio-quiet AGNs selected from the Chandra Deep Field-North and Chandra Deep Field-South surveys (hereafter, CDFs) in the redshift range of 0.1 ≲z≲ 4. We find that the X-ray power-law photon index (Gamma) of radio-quiet AGNs is correlated with their 2--10 keV rest-frame X-ray luminosity ( LX) at the > 99.5% confidence level in two redshift bins, 0.3 ≲z≲ 0.96, and 1.5 ≲z≲ 3.3 and is slightly less significant in the redshift bin 0.96 ≲z≲ 1.5. The X-ray spectral slope steepens as the X-ray luminosity increases for AGNs in the luminosity range 1042 to 1045 erg s-1. Combining our results from the CDFs with those from previous studies in the redshift range 1.5 ≲z≲ 3.3, we find that the Gamma -- L X correlation has a null-hypothesis probability of 1.6 x 10 -9. We investigate the redshift evolution of the correlation between the power-law photon index and the hard X-ray luminosity and find that the slope and offset of a linear fit to the correlation change significantly (at the > 99.9% confidence level) between redshift bins of 0.3 ≲z≲ 0.96 and 1.5 ≲z≲ 3.3. We explore physical scenarios explaining the origin of this correlation and its possible evolution with redshift in the context of steady corona models focusing on its dependency on variations of the properties of the hot corona with redshift. In chapter 3, we present results from three Suzaku observations of the z = 3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of ≲ 2 keV (low-energy) and 7--12 keV (high-energy). The detection of these features confirms the results of previous long-exposure (80--90 ks) Chandra and XMM-Newton observations. The low and high-energy absorption is detected in both the back-illuminated (BI) and front-illuminated (FI) Suzaku XIS spectra (with an F-test significance of ≳ 99%). We interpret the low-energy absorption as arising from a low-ionization absorber with log (NH/cm-2) ˜ 23 and the high-energy absorption as due to lines arising from highly ionized (2.75 ≲ log xi ≲ 4.0; where xi is the ionization parameter) iron in a near-relativistic outflowing wind. Assuming this interpretation we find that the velocities in the outflow range between 0.1c and 0.6c. We constrain the angle between the outflow direction of the X-ray absorber and our line of sight to be ≲ 36°. We also detect likely variability of the absorption lines (at the ≳ 99.9% and ≳ 98% significance levels in the FI and BI spectra, respectively) with a rest-frame time scale of ˜1 month. Assuming that the detected high-energy absorption features arise from Fe XXV, we estimate that the fraction of the total bolometric energy injected over the quasar's lifetime into the intergalactic medium in the form of kinetic energy to be ≳ 10%. In chapter 4, we present an expansion of our previous work on the study of X-ray outflows on APM 08279+5255. The main conclusions from our multi-epoch spectral analysis of Chandra, XMM-Newton and Suzaku observations of the z = 3.91 gravitationally lensed broad absorption line (BAL) quasar APM 08279+5255 are: (1) In every observation we confirm the presence of two strong features, one at rest-frame energies between 1--4 keV, and the other between 7--18 keV. (2) The low-energy absorption is interpreted as arising (1--4 keV rest-frame) from a low-ionization absorber with log (N H/cm-2) ˜ 23 and the high-energy absorption (7--18 keV rest-frame) as due to lines arising from highly ionized (3 ≲ log xi ≲ 4; where xi is the ionization parameter) iron in a near-relativistic outflowing wind. Assuming this interpretation, we find that the velocities on the outflow could get up to ˜ 0.7c. We also present results obtained from fits to all the long exposure observations of APM 08279+5255 with a new outflow model. (Abstract shortened by UMI.)

Strong-field ionization of Li and Be: a time-dependent density functional theory with self-interaction correction

NASA Astrophysics Data System (ADS)

Telnov, Dmitry A.; Heslar, John T.; Chu, Shih-I.

2011-11-01

In the framework of the time-dependent density functional theory, we have performed 3D calculations of multiphoton ionization of Li and Be atoms by strong near-infrared laser fields. The results for the intensity-dependent probabilities of single and double ionization are presented. We make use of the time-dependent Krieger-Li-Iafrate exchange-correlation potential with self-interaction correction (TD-KLI-SIC). Such a potential possesses an integer discontinuity which improves description of the ionization process. However, we have found that the discontinuity of the TD-KLI-SIC potential is not sufficient to reproduce characteristic feature of double ionization.

Tunnel ionization of highly excited atoms in a noncoherent laser radiation field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krainov, V.P.; Todirashku, S.S.

1982-10-01

A theory is developed of the ionization of highly excited atomic states by a low-frequency field of noncoherent laser radiation with a large number of modes. Analytic formulas are obtained for the probability of the tunnel ionization in such a field. An analysis is made of the case of the hydrogen atom when the parabolic quantum numbers are sufficiently good in the low-frequency limit, as well as of the case of highly excited states of complex atoms when these states are characterized by a definite orbital momentum and parity. It is concluded that the statistical factor representing the ratio ofmore » the probability in a stochastic field to the probability in a monochromatic field decreases, compared with the case of a short-range potential, if the ''Coulomb tail'' is included. It is shown that at a given field intensity the statistical factor decreases on increase in the principal quantum number of the state being ionized.« less

Plant Wax n-Alkane and n-Alkanoic Acid Signatures Overprinted by Microbial Contributions and Old Carbon in Meromictic Lake Sediments

NASA Astrophysics Data System (ADS)

Makou, Matthew; Eglinton, Timothy; McIntyre, Cameron; Montluçon, Daniel; Antheaume, Ingrid; Grossi, Vincent

2018-01-01

Specific n-alkanes and n-alkanoic acids are commonly used as biomarkers in paleoenvironmental reconstruction, yet any individual homologue may originate from multiple biological sources. Here we improve source and age controls for these compounds in meromictic systems by measuring the radiocarbon (14C) ages of specific homologues preserved in twentieth century Lake Pavin (France) sediments. In contrast to many studies, 14C ages generally decreased with increasing carbon chain length, from 7.3 to 2.6 ka for the C14-C30 n-alkanoic acids and from 9.2 to 0.3 ka for the C21-C33 n-alkanes. Given a known hard water effect, these values suggest that aquatic microbial sources predominate and contributed to most of the homologues measured. Only the longest chain n-alkanes exclusively represent inputs of higher plant waxes, which were previously sequestered in soils over centennial to millennial timescales prior to transport and deposition. These findings suggest that biomarker source and age should be carefully established for lacustrine settings.

Dynamic target ionization using an ultrashort pulse of a laser field

NASA Astrophysics Data System (ADS)

Makarov, D. N.; Matveev, V. I.; Makarova, K. A.

2014-09-01

Ionization processes under the interaction of an ultrashort pulse of an electromagnetic field with atoms in nonstationary states are considered. As an example, the ionization probability of the hydrogen-like atom upon the decay of quasi-stationary state is calculated. The method developed can be applied to complex systems, including targets in collisional states and various chemical reactions.

[Epidemiology of food insecurity in Mexico].

PubMed

Mundo-Rosas, Verónica; Shamah-Levy, Teresa; Rivera-Dommarco, Juan A

2013-01-01

To estimate the proportion of Mexican households in food insecurity (FI) and their distribution in relation to nutrition and socioeconomic conditions. We evaluated information from 40 809 households. FI was measured using a harmonized version for Mexico of the Latin American and Caribbean food Security Scale. Households were classified according to the level of food insecurity as follows: Food security, mild, moderate and severe FI. We describe the distribution of FI according to some household socioeconomic variables. Nationally, 28.2% of households had moderate or severe FI. Rural, indigenous ethnicity and household deprivation were risk factors moderate to severe FI (35.4, 42.2 and 45.9%, respectively). Severe FI was also associated with lower children height and weight. Multi-sectorial actions are needed to address the basic needs of households with moderate and severe FI.

Applied research of embedded WiFi technology in the motion capture system

NASA Astrophysics Data System (ADS)

Gui, Haixia

2012-04-01

Embedded wireless WiFi technology is one of the current wireless hot spots in network applications. This paper firstly introduces the definition and characteristics of WiFi. With the advantages of WiFi such as using no wiring, simple operation and stable transmission, this paper then gives a system design for the application of embedded wireless WiFi technology in the motion capture system. Also, it verifies the effectiveness of design in the WiFi-based wireless sensor hardware and software program.

Pollination Research Methods with Apis mellifera

USDA-ARS?s Scientific Manuscript database

This chapter describes field and lab procedures for doing experiments on honey bee pollination. Most of the methods apply to any insect for whom pollen vectoring capacity is the question. What makes honey bee pollination distinctive is its historic emphasis on agricultural applications; hence one fi...

Ambient Ionization Mass Spectrometry for Cancer Diagnosis and Surgical Margin Evaluation

PubMed Central

Ifa, Demian R.; Eberlin, Livia S.

2017-01-01

Background There is a clinical need for new technologies that would enable rapid disease diagnosis based on diagnostic molecular signatures. Ambient ionization mass spectrometry has revolutionized the means by which molecular information can be obtained from tissue samples in real time and with minimal sample pretreatment. New developments in ambient ionization techniques applied to clinical research suggest that ambient ionization mass spectrometry will soon become a routine medical tool for tissue diagnosis. Content This review summarizes the main developments in ambient ionization techniques applied to tissue analysis, with focus on desorption electrospray ionization mass spectrometry, probe electrospray ionization, touch spray, and rapid evaporative ionization mass spectrometry. We describe their applications to human cancer research and surgical margin evaluation, highlighting integrated approaches tested for ex vivo and in vivo human cancer tissue analysis. We also discuss the challenges for clinical implementation of these tools and offer perspectives on the future of the field. Summary A variety of studies have showcased the value of ambient ionization mass spectrometry for rapid and accurate cancer diagnosis. Small molecules have been identified as potential diagnostic biomarkers, including metabolites, fatty acids, and glycerophospholipids. Statistical analysis allows tissue discrimination with high accuracy rates (>95%) being common. This young field has challenges to overcome before it is ready to be broadly accepted as a medical tool for cancer diagnosis. Growing research in new, integrated ambient ionization mass spectrometry technologies and the ongoing improvements in the existing tools make this field very promising for future translation into the clinic. PMID:26555455

Ionization chamber-based reference dosimetry of intensity modulated radiation beams.

PubMed

Bouchard, Hugo; Seuntjens, Jan

2004-09-01

The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the absorbed dose to water calibration coefficient N(D, w)Q for fluence perturbation effects in individual segments of an IMRT delivery and developed a calculation method to evaluate the factor. The method consists of precalculating, using accurate Monte Carlo techniques, ionization chamber, type-dependent cavity air dose, and in-phantom dose to water at the reference point for zero-width pencil beams as a function of position of the pencil beams impinging on the phantom surface. These precalculated kernels are convolved with the IMRT fluence distribution to arrive at the dose-to-water-dose-to-cavity air ratio [D(a)w (IMRT)] for IMRT fields and with a 10x10 cm2 open-field fluence to arrive at the same ratio D(a)w (Q) for the 10x10 cm2 reference field. The correction factor C(Q)IMRT is then calculated as the ratio of D(a)w (IMRT) and D(a)w (Q). The calculation method was experimentally validated and the magnitude of chamber correction factors in reference dose measurements in single static and dynamic IMRT fields was studied. The results show that, for thimble-type ionization chambers the correction factor in a single, realistic dynamic IMRT field can be of the order of 10% or more. We therefore propose that for accurate reference dosimetry of complete n-beam IMRT deliveries, ionization chamber fluence perturbation correction factors must explicitly be taken into account.

Quasistatic limit of the strong-field approximation describing atoms in intense laser fields: Circular polarization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Jaroslaw H.

2011-03-15

In the recent work of Vanne and Saenz [Phys. Rev. A 75, 063403 (2007)] the quasistatic limit of the velocity gauge strong-field approximation describing the ionization rate of atomic or molecular systems exposed to linearly polarized laser fields was derived. It was shown that in the low-frequency limit the ionization rate is proportional to the laser frequency {omega} (for a constant intensity of the laser field). In the present work I show that for circularly polarized laser fields the ionization rate is proportional to {omega}{sup 4} for H(1s) and H(2s) atoms, to {omega}{sup 6} for H(2p{sub x}) and H(2p{sub y})more » atoms, and to {omega}{sup 8} for H(2p{sub z}) atoms. The analytical expressions for asymptotic ionization rates (which become nearly accurate in the limit {omega}{yields}0) contain no summations over multiphoton contributions. For very low laser frequencies (optical or infrared) these expressions usually remain with an order-of-magnitude agreement with the velocity gauge strong-field approximation.« less

Miniature Bipolar Electrostatic Ion Thruster

NASA Technical Reports Server (NTRS)

Hartley, Frank T.

2006-01-01

The figure presents a concept of a bipolar miniature electrostatic ion thruster for maneuvering a small spacecraft. The ionization device in the proposed thruster would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several mega-volts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. In a thruster-based on this concept, one or more propellant gases would be introduced into such a membrane ionizer. Unlike in larger prior ion thrusters, all of the propellant molecules would be ionized. This thruster would be capable of bipolar operation. There would be two accelerator grids - one located forward and one located aft of the membrane ionizer. In one mode of operation, which one could denote the forward mode, positive ions leaving the ionizer on the backside would be accelerated to high momentum by an electric field between the ionizer and an accelerator grid. Electrons leaving the ionizer on the front side would be ejected into free space by a smaller accelerating field. The equality of the ion and electron currents would eliminate the need for an additional electron- or ion-emitting device to keep the spacecraft charge-neutral. In another mode of operation, which could denote the reverse mode, the polarities of the voltages applied to the accelerator grids and to the electrodes of the membrane ionizer would be the reverse of those of the forward mode. The reversal of electric fields would cause the ion and electrons to be ejected in the reverse of their forward mode directions, thereby giving rise to thrust in the direction opposite that of the forward mode.

Simulation study of the ionizing front in the critical ionization velocity phenomenon

NASA Technical Reports Server (NTRS)

Machida, S.; Goertz, C. K.; Lu, G.

1988-01-01

The simulation of the critical ionization velocity for a neutral gas cloud moving across the static magnetic field is presented. A low-beta plasma is studied, using a two and a half-dimensional electrostatic code linked with the Plasma and Neutral Interaction Code (Goertz and Machida, 1987). The physics of the ionizing front and the instabilities which occur there are discussed. Results are presented from four numerical runs designed so that the effects of the charge separation field can be distinguished from the wave heating.

Definition, prevalence, and outcome of feeding intolerance in intensive care: a systematic review and meta-analysis.

PubMed

Blaser, A Reintam; Starkopf, J; Kirsimägi, Ü; Deane, A M

2014-09-01

Clinicians and researchers frequently use the phrase 'feeding intolerance' (FI) as a descriptive term in enterally fed critically ill patients. We aimed to: (1) determine what is the most accepted definition of FI; (2) estimate the prevalence of FI; and (3) evaluate whether FI is associated with important outcomes. Systematic searches of peer-reviewed publications using PubMed, MEDLINE, and Web of Science were performed with studies reporting FI extracted. We identified 72 studies defining FI. In 33 studies, the definition was based on large gastric residual volumes (GRVs) together with other gastrointestinal symptoms, while 30 studies relied solely on large GRVs, six studies used inadequate delivery of enteral nutrition (EN) as a threshold, and three studies gastrointestinal symptoms without reference to GRV. The median volume used to define a 'large' GRV was 250 ml (ranges from 75 to 500 ml). The pooled proportion (n = 31 studies) of FI was 38.3% (95% CI 30.7-46.2). Five studies reported outcomes, all of them observed adverse outcome in FI patients. In three studies, respectively, FI was associated with increased mortality and ICU length-of-stay. In summary, FI is inconsistently defined but appears to occur frequently. There are preliminary data indicating that FI is associated with adverse outcomes. A standard definition of FI is required to determine the accuracy of these preliminary data. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Fecal incontinence in irritable bowel syndrome (IBS): Prevalence and associated factors in Swedish and American patients

PubMed Central

Simrén, Magnus; Palsson, Olafur S.; Heymen, Steve; Bajor, Antal; Törnblom, Hans; Whitehead, William E.

2016-01-01

Background Fecal incontinence (FI) is a prevalent but poorly recognized problem in the general population with profound negative effects on daily life. The prevalence of FI in IBS and its association with clinical, demographic and pathophysiological factors are largely unknown. Methods One US (n=304) and one Swedish (n=168) patient cohort fulfilling Rome III criteria for IBS completed Rome III diagnostic questions on FI and IBS symptoms, and questionnaires on IBS symptom severity, quality of life, anxiety and depression, and work productivity impairment. The patients also underwent assessments of colorectal sensitivity and motility. Key Results FI ≥ one day per month was reported by 19.7% (USA) and 13.7% (Sweden) of IBS patients. These proportions rose to 43.4% and 29.8% if patients with less frequent FI were included. FI prevalence was higher in older age groups, with a clear increase above age 40. IBS patients with FI reported greater overall IBS symptom severity, more frequent and loose stools, and greater urgency. Negative effects of FI on quality of life, psychological distress, and work productivity were demonstrated. No associations were found between colorectal physiology and FI. Conclusions & Inferences FI is common in IBS patients, and similar to previous general population reports, the major risk factors for FI in IBS are older age, rectal urgency, and loose, frequent stools. When IBS patients have comorbid FI, the impact on quality of life, psychological symptoms, and work impairment appears greater. PMID:27581702

Robust generation of Fourier-synthesized laser fields and their estimation of the optical phase by using quantum control of molecular tunneling ionization

NASA Astrophysics Data System (ADS)

Yoshida, Tsuyoshi; Saito, Naoaki; Ohmura, Hideki

2018-03-01

Intense (5.0 × 1012 W cm-2) nanosecond Fourier-synthesized laser fields consisting of fundamental, second-, third-, and fourth-harmonic light generated by an interferometer-free Fourier-synthesized laser field generator induce orientation-selective ionization based on directionally asymmetric molecular tunneling ionization (TI). The laser field generator ensures adjustment-free operation, high stability, and high reproducibility. Phase-sensitive, orientation-selective molecular TI provides a simple way to estimate the relative phase differences between the fundamental light and each harmonic by data-fitting analysis. This application of Fourier-synthesized laser fields will facilitate not only lightwave engineering but also the control of matter.

TET Offensive II Field Force Vietnam After Action Report 31 January - 18 February 1968

DTIC Science & Technology

1968-03-01

and the 5th VC Division. V During this same period of time there were no majur shifts in ARVN forces . However III Corps shifted three...8217-".•: ’ ’SSIFJED U.S. ARMY. VIETNAM. II FIELD FORCE . TET OFFENSIVE II FIELD FORCE VIETNAM AFTER ACTION REPORT, 31 JANUARY-18 FEB- RUARY 1968...H FIELD FORCE VIETNAM AFTER ACTION REPORT 31 January-18 February 1968 RECORD K0- ! FlSjl fi-.-A-,>-•: it tT*\\ : *si h s» -wP Mr-, £< St

Creativity of Field-dependent and Field-independent Students in Posing Mathematical Problems

NASA Astrophysics Data System (ADS)

Azlina, N.; Amin, S. M.; Lukito, A.

2018-01-01

This study aims at describing the creativity of elementary school students with different cognitive styles in mathematical problem-posing. The posed problems were assessed based on three components of creativity, namely fluency, flexibility, and novelty. The free-type problem posing was used in this study. This study is a descriptive research with qualitative approach. Data collections were conducted through written task and task-based interviews. The subjects were two elementary students. One of them is Field Dependent (FD) and the other is Field Independent (FI) which were measured by GEFT (Group Embedded Figures Test). Further, the data were analyzed based on creativity components. The results show thatFD student’s posed problems have fulfilled the two components of creativity namely fluency, in which the subject posed at least 3 mathematical problems, and flexibility, in whichthe subject posed problems with at least 3 different categories/ideas. Meanwhile,FI student’s posed problems have fulfilled all three components of creativity, namely fluency, in which thesubject posed at least 3 mathematical problems, flexibility, in which thesubject posed problems with at least 3 different categories/ideas, and novelty, in which the subject posed problems that are purely the result of her own ideas and different from problems they have known.

Turbulence scaling study in an MHD wind tunnel on the Swarthmore Spheromak Experiment

NASA Astrophysics Data System (ADS)

Schaffner, D. A.; Brown, M. R.; Wan, A.

2013-12-01

The turbulence of colliding plasmas is explored in an MHD wind tunnel on the SSX in an effort to understand solar wind physics in a laboratory setting. Fully ionized hydrogen plasma is produced by two plasma guns on opposite sides of a 1m by 15cm copper cylinder creating plasma with L/ρi ~ 75-150, β ~ 0.1-0.2 and Lundquist number ~ 1000. Modification of B-field, Ti and β are made through stuffing flux variation of the plasma guns. Presented here are turbulent f-/k-spectra and correlation times and lengths of B-field fluctuations as measured by a 16 channel B-dot radial probe array at the chamber midplane using both FFT and wavelet analysis techniques. Power-law behavior is observed spanning about two decades of frequencies [100kHz-10MHz] and about one decade of wavelength [10cm-1cm]. Power-law fits to spectra show scaling in these regions to be robust to changes in stuffing flux; fits are on the order of f-4 and k-2 for all flux variations. Low frequency fluctuations [<100kHz] can vary significantly suggesting a range of energy injection at large scales. Evidence for dissipation range modification of the spectra is also observed; divergence from power-law behavior is seen in f-spectra for frequencies around f=fci while changes in k-spectra slopes appear around 1/k ~ 5ρi. Dissipation range fits are made with an exponentially modified power-law model [Terry et al, PoP 2012]. Fluctuation measurements in axial velocity are made using a Mach probe with edge flows reaching M ~ 0.4. Both B-field and velocity fluctuations persist on the same timescale in these experiments, though Mach velocity f-spectra show power-laws slightly shallower than those for B-field. Comparison of spectra from MHD and Hall MHD simulations of SSX performed within the HiFi modeling framework are made to the experimental results.

Internuclear separation dependent ionization of the valence orbitals of I2 by strong laser fields.

PubMed

Chen, H; Tagliamonti, V; Gibson, G N

2012-11-09

Using a pump-dump-probe technique and Fourier-transform spectroscopy, we study the internuclear separation R dependence and relative strength of the ionization rates of the π and σ electrons of I2, whose valence orbitals are σ(g)(2)π(u)(4)π(g)(4)σ(u)(0). We find that ionization of the highest occupied molecular orbital (HOMO)-2 (σ(g)) has a strong dependence on R while the HOMO and HOMO-1 do not. Surprisingly, the ionization rate of the HOMO-2 exceeds the combined ionization rate of the less bound orbitals and this branching ratio increases with R. Since our technique produces target molecules that are highly aligned with the laser polarization, the σ orbitals will be preferentially ionized and undergo enhanced ionization at larger R compared to the π orbitals. Nevertheless, it is highly unusual that an inner orbital provides the dominant strong field ionization pathway in a small molecule.

Internuclear Separation Dependent Ionization of the Valence Orbitals of I2 by Strong Laser Fields

NASA Astrophysics Data System (ADS)

Chen, H.; Tagliamonti, V.; Gibson, G. N.

2012-11-01

Using a pump-dump-probe technique and Fourier-transform spectroscopy, we study the internuclear separation R dependence and relative strength of the ionization rates of the π and σ electrons of I2, whose valence orbitals are σg2πu4πg4σu0. We find that ionization of the highest occupied molecular orbital (HOMO)-2 (σg) has a strong dependence on R while the HOMO and HOMO-1 do not. Surprisingly, the ionization rate of the HOMO-2 exceeds the combined ionization rate of the less bound orbitals and this branching ratio increases with R. Since our technique produces target molecules that are highly aligned with the laser polarization, the σ orbitals will be preferentially ionized and undergo enhanced ionization at larger R compared to the π orbitals. Nevertheless, it is highly unusual that an inner orbital provides the dominant strong field ionization pathway in a small molecule.

Bound and continuum energy distributions of nuclear fragments resulting from tunneling ionization of molecules

NASA Astrophysics Data System (ADS)

Svensmark, Jens; Tolstikhin, Oleg I.; Madsen, Lars Bojer

2018-03-01

We present the theory of tunneling ionization of molecules with both electronic and nuclear motion treated quantum mechanically. The theory provides partial rates for ionization into the different final states of the molecular ion, including both bound vibrational and dissociative channels. The exact results obtained for a one-dimensional model of H2 and D2 are compared with two approximate approaches, the weak-field asymptotic theory and the Born-Oppenheimer approximation. The validity ranges and compatibility of the approaches are identified formally and illustrated by the calculations. The results quantify that at typical field strengths considered in strong-field physics, it is several orders of magnitude more likely to ionize into bound vibrational ionic channels than into the dissociative channel.

Field-scale modeling of center pivot irrigated cotton: Oullman clay loam series

USDA-ARS?s Scientific Manuscript database

Regulatory ground water pumping restrictions continue to be debated in the Southern Ogallala Aquifer region and will eventually result in allocation of irrigation resources becoming more important. Models that address the temporal and spatial variability of water, energy, and nutrient balances at fi...

Coherent control of strong-field two-pulse ionization of Rydberg atoms.

PubMed

Fedorov, M; Poluektov, N

2000-02-28

Strong-field ionization of Rydberg atoms is investigated in its dependence on phase features of the initial coherent population of Rydberg levels. In the case of a resonance between Rydberg levels and some lower-energy atomic level (V-type transitions), this dependence is shown to be very strong: by a proper choice of the initial population an atom can be made either completely or very little ionized by a strong laser pulse. It is shown that phase features of the initial coherent population of Rydberg levels and the ionization yield can be efficiently controlled in a scheme of ionization by two strong laser pulses with a varying delay time between them.

High-frequency, high-intensity photoionization

NASA Astrophysics Data System (ADS)

Reiss, H. R.

1996-02-01

Two analytical methods for computing ionization by high-frequency fields are compared. Predicted ionization rates compare well, but energy predictions for the onset of ionization differ radically. The difference is shown to arise from the use of a transformation in one of the methods that alters the zero from which energy is measured. This alteration leads to an apparent energy threshold for ionization that can, especially in the stabilization regime, differ strongly from the laboratory measurement. It is concluded that channel closings in intense-field ionization can occur at high as well as low frequencies. It is also found that the stabilization phenomenon at high frequencies, very prominent for hydrogen, is absent in a short-range potential.

Strategic competence of senior secondary school students in solving mathematics problem based on cognitive style

NASA Astrophysics Data System (ADS)

Syukriani, Andi; Juniati, Dwi; Siswono, Tatag Yuli Eko

2017-08-01

The purpose of this study was to explore the strategic competence of senior secondary school students in solving mathematics problems. Terdapat dua subjek, satu bergaya kognitif field-independent dan satu bergaya kognitif field-dependent tetapi keduanya memiliki tingkat prestasi belajar matematika yang setara. There were two subjects, one field-independent cognitive style and one field-dependent cognitive style. They had an equivalent high level of mathematics achievement. Keduanya dipilih berdasarkan hasil tes kompetensi matematika dan GEFT (Group Embedded Figures Test). Subjects were selected based on the test results of mathematics competence and GEFT (Group Embedded Figures Test). Kompetensi strategis dapat merangsang perkembangan otonomi dan fleksibilitas dalam diri siswa karena merupakan keterampilan yang sangat dibutuhkan di sepanjang abad 21. Gaya kognitif merupakan kecenderungan siswa dalam mengolah informasi sangat mempengaruhi performance dalam menyelesaikan masalah matematika. Strategic competence can stimulate the development of autonomy and flexibility of students and they are skills which are needed in the 21st century. Cognitive style is the tendency of students in processing informations and it greatly affects the performance in solving mathematics problems. Hasil penelitian menunjukkan bahwa subjek FI cenderung analitis baik pada pembentukan bayangannya maupun pada gambar yang dibuatnya untuk memproses informasi berdasarkan dengan struktur pengetahuannya sendiri (Internally directed). The research result showed that subject FI tended to be analytical both in forming the mental imagination and the picture to process information in accordance with his own knowledge structure (internally directed). Subjek FD kurang analitis dan tidak dapat mengenal bentuk sederhana (konsep matematika) dari bentuk yang kompleks (Exeternally directed) sehingga menerima ide sebagaimana yang disajikan. Subject FD was less analytical and unable to recognize simple form (mathematical concept) of a complex form (Externally directed), so he received the idea as presented. Hasil penelitian ini penting sebagai bahan masukan untuk guru dan pengembang ilmu pendidikan matematika untuk meningkatkan fleksibilitas (Flexibility) siswa dalam keberagaman karakteristiknya melalui penelitian terkait dengan pengembangan bahan instruksi, perangkat dan model pembelajaran matematika. The results of this research are important as input for teachers and mathematics education developers to increase the flexibility of students in the characteristics diversity through the research related to the development of instruction materials and mathematics learning model. Penelitian selanjutnya, sebaiknya melihat bagaimana FI dan FD dapat memberikan penjelasan dan pembenaran atas strategi yang telah diusahakan supaya terlihat lebih jelas bagaimana perbedaan FI dan FD dalam mengkontruksi konsep matematika pada pengalaman belajarnya Further research should study about how the explanation and justification for the strategy that has been attempted in order to look more clearly how constructing mathematical concepts in their learning experience.

Carbon dioxide and methane dynamics in a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Yu, Zhongjie; Wang, Dongqi; Li, Yangjie; Deng, Huanguang; Hu, Beibei; Ye, Mingwu; Zhou, Xuhui; Da, Liangjun; Chen, Zhenlou; Xu, Shiyuan

2017-07-01

Evasion of carbon dioxide (CO2) and methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CO2 and CH4 dynamics in lowland coastal rivers profoundly modified by anthropogenic perturbations. Here we report results from a long-term, large-scale study of CO2 and CH4 partial pressures (pCO2 and pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variabilities of pCO2 and pCH4 were examined along a land use gradient, and the annual CO2 and CH4 evasion were estimated to assess its role in regional C budget. During the study period (August 2009 to October 2011), the overall mean pCO2 and median pCH4 from 87 surveyed rivers were 5846 ± 2773 μatm and 241 μatm, respectively. Internal metabolic CO2 production and dissolved inorganic carbon input via upstream runoff were the major sources sustaining the widespread CO2 supersaturation, coupling pCO2 to biogeochemical and hydrological controls, respectively. While CH4 was oversaturated throughout the river network, CH4 hot spots were concentrated in the small urban rivers and highly discharge-dependent. The Shanghai river network played a disproportionately important role in regional C budget, offsetting up to 40% of the regional terrestrial net ecosystem production and 10% of net C uptake in the river-dominated East China Sea fueled by anthropogenic nutrient input. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

[Food insecurity in the state of Nayarit, Mexico, and its association with socioeconomic factors].

PubMed

Haro-Mota, Rebeca de; Marceleño-Flores, Susana; Bojórquez-Serrano, José Irán; Nájera-González, Oyolsi

2016-08-01

Objetive: To estimate the proportion of households with food insecurity (FI) in twenty municipalities in the state of Nayarit, Mexico, and to identify the factors that determine it. FI was estimated using the harmonized version for Mexico of the Latin American and Caribbean household food security scale (ELCSA). Households were classified according to FI level: mild, moderate and severe. The distribution of FI was described by type of locality and prevalence of FI was analyzed by associated variables. 76.2% of households were identified with some FI level.The prevalence of FI was higher in rural households. Food insecurity situation was focused on households with the highest number of children under five years, highest number of older than 64 years, highest number of household members, female headship and less schooling of the household head. ELCSA can be useful to associate FI with socioeconomic factors.

Questioning the Influence of Sunspots on Amazon Hydrology: Even a Broken Clock Tells the Right Time Twice a Day

NASA Astrophysics Data System (ADS)

Baker, J. C. A.; Gloor, M.; Boom, A.; Neill, D. A.; Cintra, B. B. L.; Clerici, S. J.; Brienen, R. J. W.

2018-02-01

It was suggested in a recent article that sunspots drive decadal variation in Amazon River flow. This conclusion was based on a novel time series decomposition method used to extract a decadal signal from the Amazon River record. We have extended this analysis back in time, using a new hydrological proxy record of tree ring oxygen isotopes (δ18OTR). Consistent with the findings of Antico and Torres, we find a positive correlation between sunspots and the decadal δ18OTR cycle from 1903 to 2012 (r = 0.60, p < 0.001). However, the relationship does not persist into the preceding century and even becomes weakly negative (r = -0.30, p = 0.11, 1799-1902). This result casts considerable doubt over the mechanism by which sunspots are purported to influence Amazon hydrology.

Miniature Oxidizer Ionizer for a Fuel Cell

NASA Technical Reports Server (NTRS)

Hartley, Frank

2006-01-01

A proposed miniature device for ionizing the oxygen (or other oxidizing gas) in a fuel cell would consist mostly of a membrane ionizer using the same principles as those of the device described in the earlier article, Miniature Bipolar Electrostatic Ion Thruster (NPO-21057). The oxidizing gas would be completely ionized upon passage through the holes in the membrane ionizer. The resulting positively charged atoms or molecules of oxidizing gas could then, under the influence of the fringe fields of the ionizer, move toward the fuel-cell cathode that would be part of a membrane/electrode assembly comprising the cathode, a solid-electrolyte membrane, and an anode. The electro-oxidized state of the oxidizer atoms and molecules would enhance transfer of them through the cathode, thereby reducing the partial pressure of the oxidizer gas between the ionizer and the fuel-cell cathode, thereby, in turn, causing further inflow of oxidizer gas through the holes in the membrane ionizer. Optionally the ionizer could be maintained at a positive electric potential with respect to the cathode, in which case the resulting electric field would accelerate the ions toward the cathode.

Hot interstellar gas and ionization of embedded clouds

NASA Technical Reports Server (NTRS)

Cheng, K.-P.; Bruhweiler, F.

1990-01-01

Researchers present detailed photoionization calculations for the instellar cloud in which the Sun is embedded. They consider the EUV radiation field with contribution from discrete stellar sources and from a thermal bremsstrahlung-radiative recombination spectrum emitted from the surrounding 10 to the 6th power k coronal substrate. They establish lower limits to the fractional ionization of hydrogen and helium of 0.17 and 0.29 respectively. The high He ionization fraction results primarily from very strong line emission below 500 A originating in the surrounding coronal substrate while the H ionization is dominated by the EUV radiation from the discrete stellar sources. The dual effects of thermal conduction and the EUV spectrum of the 10 to the 6th k plasma on ionization in the cloud skin are explored. The EUV radiation field and Auger ionization have insignificant effects on the resulting ionic column densities of Si IV, C IV, N V and O VI through the cloud skin. Calculations show that the abundances of these species are dominated by collisional ionization in the thermal conduction front. Because of a low charge exchange rate with hydrogen, the ionic column density ratios of N (CIII)/N (CII) and N (NII)/N (NI) are dominated by the EUV radiation field in the local interstellar medium. These ratios should be important diagnostics for the EUV radiation field and serve as surrogate indicators of the interstellar He and H ionization fraction respectively. Spacecraft such as Lyman which is designed to obtain high resolution spectral data down to the Lyman limit at 912 A could sample interstellar lines of these ions.

Double ionization of nitrogen molecules in orthogonal two-color femtosecond laser fields

NASA Astrophysics Data System (ADS)

Song, Qiying; Li, Hui; Wang, Junping; Lu, Peifen; Gong, Xiaochun; Ji, Qinying; Lin, Kang; Zhang, Wenbin; Ma, Junyang; Li, Hanxiao; Zeng, Heping; He, Feng; Wu, Jian

2018-04-01

Double ionization of nitrogen molecules in orthogonally polarized two-color femtosecond laser fields is investigated by varying the relative intensity between the fundamental wave (FW) and its second harmonic (SH) components. The yield ratios of the double ionization channels, i.e., the non-dissociative {{{{N}}}2}2+ and Coulomb exploded (N+, N+), to the singly charged N2 + channel exhibit distinct dependences on the relative strength between the FW and SH fields. As the intensity ratio of SH to FW increases, the yield ratio of (N+, N+)/N2 + gradually increases, while the ratio of {{{{N}}}2}2+/N2 + first descends and then increases constituting a valley shape which is similar to the behavior of Ar2+/Ar+ observed in the same experimental condition. Based on the classical trajectory simulations, we found that the different characteristics of the two doubly ionized channels stem from two mechanisms, i.e., the {{{{N}}}2}2+ is mostly accessed by the (e, 2e) impact ionization while the recollision-induced excitation with subsequent ionization plays an important role in producing the (N+, N+) channel.

Comparison study for multiple ionization of carbonyl sulfide by linearly and circularly polarized intense femtosecond laser fields using Coulomb explosion imaging

NASA Astrophysics Data System (ADS)

Ma, Pan; Wang, Chuncheng; Luo, Sizuo; Yu, Xitao; Li, Xiaokai; Wang, Zhenzhen; Hu, Wenhui; Yu, Jiaqi; Yang, Yizhang; Tian, Xu; Cui, Zhonghua; Ding, Dajun

2018-05-01

We studied the relative yields and dissociation dynamics for two- and three-body Coulomb explosion (CE) channels from highly charged carbonyl sulfide molecules in intense laser fields using the CE imaging technique. The electron recollision contributions are evaluated by comparing the relative yields for the multiple ionization process in linearly polarized and circularly polarized (LP and CP) laser fields. The nonsequential multiple ionization is only confirmed for the charge states of 2 to 4 because the energy for further ionization from the inner orbital is much larger than the maximum recollision energy, 3.2U p . The novel deviations of kinetic energy releases distributions between LP and CP pulses are observed for the charge states higher than 4. It can be attributed to the stronger molecular bending in highly charged states before three-body CE with CP light, in which the bending wave packet is initialed by the triple or quartic ionization and spread along their potential curves. Compared to LP light, CP light ionizes a larger fraction of bending molecules in the polarization plane.

Influence of field emission on the propagation of cylindrical fast ionization wave in atmospheric-pressure nitrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levko, Dmitry; Raja, Laxminarayan L.

2016-04-21

The influence of field emission of electrons from surfaces on the fast ionization wave (FIW) propagation in high-voltage nanosecond pulse discharge in the atmospheric-pressure nitrogen is studied by a one-dimensional Particle-in-Cell Monte Carlo Collisions model. A strong influence of field emission on the FIW dynamics and plasma parameters is obtained. Namely, the accounting for the field emission makes possible the bridging of the cathode–anode gap by rather dense plasma (∼10{sup 13 }cm{sup −3}) in less than 1 ns. This is explained by the generation of runaway electrons from the field emitted electrons. These electrons are able to cross the entire gap pre-ionizingmore » it and promoting the ionization wave propagation. We have found that the propagation of runaway electrons through the gap cannot be accompanied by the streamer propagation, because the runaway electrons align the plasma density gradients. In addition, we have obtained that the field enhancement factor allows controlling the speed of ionization wave propagation.« less

Implications of food insecurity on global health policy and nursing practice.

PubMed

Kregg-Byers, Claudia M; Schlenk, Elizabeth A

2010-09-01

The purpose is to discuss the concept of food insecurity (FI) and its impact on current global health policy and nursing practice. Food insecurity. Literature review. FI means a nonsustainable food system that interferes with optimal self-reliance and social justice. Individuals experiencing FI lack nutritionally adequate and safe foods in their diet. Resources play a significant role in FI by affecting whether or not people obtain culturally, socially acceptable food through regular marketplace sources as opposed to severe coping strategies, such as emergency food sources, scavenging, and stealing. Persons who are living in poverty, female heads of household, single parents, people living with many siblings, landless people, migrants, immigrants, and those living in certain geographical regions constitute populations at risk and most vulnerable to FI. FI influences economics through annual losses of gross domestic product due to reduced human productivity. FI affects individuals and households and is largely an unobservable condition, making data collection and analysis challenging. Policy and research have focused on macronutrient sufficiency and deprivation, making it difficult to draw attention and research dollars to FI. Persons experiencing FI exhibit clinical signs such as less healthy diets, poor health status, poor diabetes and chronic disease management, and impaired cognitive function. Nurses can recognize the physical, psychosocial, and personal consequences that those with FI face and manage daily.

TEMPEST simulations of the neoclassical transport in a single-null tokamak geometry

NASA Astrophysics Data System (ADS)

Xu, X. Q.; Cohen, R. H.; Rognlien, T. D.

2009-05-01

TEMPEST simulations were carried out for plasma transport and flow dynamics in a single-null tokamak geometry. The core radial boundary ion distribution is a fixed Maxwellian FM with N0=N(ψ0) and Ti0=Ti(ψ0)=300eV, and exterior radial boundary ion distribution is Neumann boundary condition with Fi(,,μ)/ψ|ψw=0 during a simulation. Given boundary conditions and initial profiles, the interior plasmas in the simulations should evolve into a neoclassical steady state. A volume source term in the private flux region is included, representing the ionization in the private flux region to achieve the neoclassical steady state. A series of TEMPEST simulations are conducted to investigate the scaling characteristics of the neoclassical transport and flow as a function of ν*i via a density scan. Here ν*i is the effective collision frequency, defined by ν*i=&-3/2circ;νii√2qR0/vTi, νii is the ion-ion collision, and vTi the ion thermal velocity. Simulation results show significant poloidal variation of density and ion temperature profiles due to the endloss machanism at the divertor plates. Each region (Edge, the SOL and private flux) achieves the dynamical steady state at its own time scale due to the different physical processes. The impact of self-consistent electric field on transport and flow will be presented.

Identifying drought adaptive traits in upland cotton using a proximal sensing cart for high-throughput phenotyping

USDA-ARS?s Scientific Manuscript database

Field-based high-throughput phenotyping is an emerging approach to characterize difficult, time-sensitive plant traits in relevant growing conditions. Proximal sensing carts have been developed as an alternative platform to more costly high-clearance tractors for phenotyping dynamic traits in the fi...

Evaluation of a New Fracture Toughness Measuring Technique, and Adaptation of the Technique to Use Ultra-Small Specimens

DTIC Science & Technology

1979-09-01

University of Michigan, 2046 East Engineering, Ann Arbor, Michigan 48109 1 Dr. R.Foye, Army Research and Technology Lab, Air Movility R&D Lab, Ames Research Center, Moffett Field, California 94035 fI nu l nmIl l l l l

Regional assemblages of Lygus (Heteroptera: Miridae) in Montana canola fields

USDA-ARS?s Scientific Manuscript database

Sweep net sampling of canola (Brassica napus L.) was conducted in 2002 and 2003 to determine Lygus (Heteroptera: Miridae) species composition and parasitism levels in four regions of Montana. Regardless of region or seasonal change, Lygus elisus (Van Duzee) was the dominant species in all canola fi...

RELATIONSHIP BETWEEN DEHALOCOCCOIDES DNA IN GROUND WATER AND RATES OF REDUCTIVE DECHLORINATION AT FIELD SCALE

EPA Science Inventory

Certain strains of Dehalococcodies bacteria can dechlorinate chlorinated ethylenes to harmless products. This study was conducted to determine if there is a valid association between the amount of DNA of Dehalococcodies sp. in ground water and useful rates of dechlorination in fi...

Progress and prospects for an FI relevant point design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Key, M; Amendt, P; Bellei, C

The physics issues involved in scaling from sub ignition to high gain fast ignition are discussed. Successful point designs must collimate the electrons and minimize the stand off distance to avoid multi mega-joule ignition energies. Collimating B field configurations are identified and some initial designs are explored.

Suburban Families' Experience With Food Insecurity Screening in Primary Care Practices.

PubMed

Palakshappa, Deepak; Doupnik, Stephanie; Vasan, Aditi; Khan, Saba; Seifu, Leah; Feudtner, Chris; Fiks, Alexander G

2017-07-01

Food insecurity (FI) remains a major public health problem. With the rise in suburban poverty, a greater understanding of parents' experiences of FI in suburban settings is needed to effectively screen and address FI in suburban practices. We conducted 23 semistructured interviews with parents of children <4 years of age who presented for well-child care in 6 suburban pediatric practices and screened positive for FI. In the interviews, we elicited parents' perceptions of screening for FI, how FI impacted the family, and recommendations for how practices could more effectively address FI. All interviews were audio recorded and transcribed. We used a modified grounded theory approach to code the interviews inductively and identified emerging themes through an iterative process. Interviews continued until thematic saturation was achieved. Of the 23 parents interviewed, all were women, with 39% white and 39% African American. Three primary themes emerged: Parents expressed initial surprise at screening followed by comfort discussing their unmet food needs; parents experience shame, frustration, and helplessness regarding FI, but discussing FI with their clinician helped alleviate these feelings; parents suggested practices could help them more directly access food resources, which, depending on income, may not be available to them through government programs. Although most parents were comfortable discussing FI, they felt it was important for clinicians to acknowledge their frustrations with FI and facilitate access to a range of food resources. Copyright © 2017 by the American Academy of Pediatrics.

Incompressible inelasticity as an essential ingredient for the validity of the kinematic decomposition F =FeFi

NASA Astrophysics Data System (ADS)

Reina, Celia; Conti, Sergio

2017-10-01

The multiplicative decomposition of the total deformation F =FeFi between an elastic (Fe) and an inelastic component (Fi) is standard in the modeling of many irreversible processes such as plasticity, growth, thermoelasticity, viscoelasticty or phase transformations. The heuristic argument for such kinematic assumption is based on the chain rule for the compatible scenario (CurlFi = 0) where the individual deformation tensors are gradients of deformation mappings, i.e. F = D φ = D (φe ∘φi) = (Dφe) ∘φi (Dφi) =FeFi . Yet, the conditions for its validity in the general incompatible case (CurlFi ≠ 0) has so far remained uncertain. We show in this paper that detFi = 1 and CurlFi bounded are necessary and sufficient conditions for the validity of F =FeFi for a wide range of inelastic processes. In particular, in the context of crystal plasticity, we demonstrate via rigorous homogenization from discrete dislocations to the continuum level in two dimensions, that the volume preserving property of the mechanistics of dislocation glide, combined with a finite dislocation density, is sufficient to deliver F =FeFp at the continuum scale. We then generalize this result to general two-dimensional inelastic processes that may be described at a lower dimensional scale via a multiplicative decomposition while exhibiting a finite density of incompatibilities. The necessity of the conditions detFi = 1 and CurlFi bounded for such systems is demonstrated via suitable counterexamples.

Interplay between Coulomb-focusing and non-dipole effects in strong-field ionization with elliptical polarization

NASA Astrophysics Data System (ADS)

Daněk, J.; Klaiber, M.; Hatsagortsyan, K. Z.; Keitel, C. H.; Willenberg, B.; Maurer, J.; Mayer, B. W.; Phillips, C. R.; Gallmann, L.; Keller, U.

2018-06-01

We study strong-field ionization and rescattering beyond the long-wavelength limit of the dipole approximation with elliptically polarized mid-IR laser pulses. Full three-dimensional photoelectron momentum distributions (PMDs) measured with velocity map imaging and tomographic reconstruction revealed an unexpected sharp ridge structure in the polarization plane (2018 Phys. Rev. A 97 013404). This thin line-shaped ridge structure for low-energy photoelectrons is correlated with the ellipticity-dependent asymmetry of the PMD along the beam propagation direction. The peak of the projection of the PMD onto the beam propagation axis is shifted from negative to positive values when the sharp ridge fades away with increasing ellipticity. With classical trajectory Monte Carlo simulations and analytical analysis, we study the underlying physics of this feature. The underlying physics is based on the interplay between the lateral drift of the ionized electron, the laser magnetic field induced drift in the laser propagation direction, and Coulomb focusing. To apply our observations to emerging techniques relying on strong-field ionization processes, including time-resolved holography and molecular imaging, we present a detailed classical trajectory-based analysis of our observations. The analysis leads to the explanation of the fine structure of the ridge and its non-dipole behavior upon rescattering while introducing restrictions on the ellipticity. These restrictions as well as the ionization and recollision phases provide additional observables to gain information on the timing of the ionization and recollision process and non-dipole properties of the ionization process.

Evaluating the patterns of spatiotemporal trends of root zone soil moisture in major climate regions in East Asia

NASA Astrophysics Data System (ADS)

Zohaib, Muhammad; Kim, Hyunglok; Choi, Minha

2017-08-01

Root zone soil moisture (RZSM) is a crucial variable in land-atmosphere interactions. Evaluating the spatiotemporal trends and variability patterns of RZSM are essential for discerning the anthropogenic and climate change effects on the regional and global hydrological cycles. In this study, the trends of RZSM, computed by the exponential filter from the European Space Agency's Climate Change Initiative soil moisture, were evaluated in major climate regions of East Asia from 1982 to 2014. Moreover, the trends of RZSM were compared to the trends of precipitation (P), skin temperature (Tskin), and actual evapotranspiration (AET) to investigate how they influence the RZSM trends in each climate region. Drying trends were predominant in arid and continental regions, whereas wetting trends were found in the tropical and temperate regions. The increasing trends of Tskin and AET cause drying in arid and continental regions, whereas in tropical regions, these cause wetting trends, which might be due to convective P. In temperate regions, despite decreasing P and increasing Tskin, the RZSM trend was increasing, attributed to the intensive irrigation activities in these regions. This is probably the first time to analyze the long-term trends of RZSM in different climate regions. Hence, the results of this study will improve our understanding of the regional and global hydrological cycles. Despite certain limitations, the results of this study may be useful for improving and developing climate models and predicting long-term vast scale natural disasters such as drought, dust outbreaks, floods, and heat waves.

Stress-dependent permeability and wave dispersion in tight cracked rocks: Experimental validation of simple effective medium models

NASA Astrophysics Data System (ADS)

Sarout, Joel; Cazes, Emilie; Delle Piane, Claudio; Arena, Alessio; Esteban, Lionel

2017-08-01

We experimentally assess the impact of microstructure, pore fluid, and frequency on wave velocity, wave dispersion, and permeability in thermally cracked Carrara marble under effective pressure up to 50 MPa. The cracked rock is isotropic, and we observe that (1) P and S wave velocities at 500 kHz and the low-strain (<10-5) mechanical moduli at 0.01 Hz are pressure-dependent, (2) permeability decreases asymptotically toward a small value with increasing pressure, (3) wave dispersion between 0.01 Hz and 500 MHz in the water-saturated rock reaches a maximum of 26% for S waves and 9% for P waves at 1 MPa, and (4) wave dispersion virtually vanishes above 30 MPa. Assuming no interactions between the cracks, effective medium theory is used to model the rock's elastic response and its permeability. P and S wave velocity data are jointly inverted to recover the crack density and effective aspect ratio. The permeability data are inverted to recover the cracks' effective radius. These parameters lead to a good agreement between predicted and measured wave velocities, dispersion and permeability up to 50 MPa, and up to a crack density of 0.5. The evolution of the crack parameters suggests that three deformation regimes exist: (1) contact between cracks' surface asperities up to 10 MPa, (2) progressive crack closure between 10 and 30 MPa, and (3) crack closure effectively complete above 30 MPa. The derived crack parameters differ significantly from those obtained by analysis of 2-D electron microscope images of thin sections or 3-D X-ray microtomographic images of millimeter-size specimens.

CIFOG: Cosmological Ionization Fields frOm Galaxies

NASA Astrophysics Data System (ADS)

Hutter, Anne

2018-03-01

CIFOG is a versatile MPI-parallelised semi-numerical tool to perform simulations of the Epoch of Reionization. From a set of evolving cosmological gas density and ionizing emissivity fields, it computes the time and spatially dependent ionization of neutral hydrogen (HI), neutral (HeI) and singly ionized helium (HeII) in the intergalactic medium (IGM). The code accounts for HII, HeII, HeIII recombinations, and provides different descriptions for the photoionization rate that are used to calculate the residual HI fraction in ionized regions. This tool has been designed to be coupled to semi-analytic galaxy formation models or hydrodynamical simulations. The modular fashion of the code allows the user to easily introduce new descriptions for recombinations and the photoionization rate.

Ionizing potential waves and high-voltage breakdown streamers.

NASA Technical Reports Server (NTRS)

Albright, N. W.; Tidman, D. A.

1972-01-01

The structure of ionizing potential waves driven by a strong electric field in a dense gas is discussed. Negative breakdown waves are found to propagate with a velocity proportional to the electric field normal to the wavefront. This causes a curved ionizing potential wavefront to focus down into a filamentary structure, and may provide the reason why breakdown in dense gases propagates in the form of a narrow leader streamer instead of a broad wavefront.

Direct Simulation of Reentry Flows with Ionization

NASA Technical Reports Server (NTRS)

Carlson, Ann B.; Hassan, H. A.

1989-01-01

The Direct Simulation Monte Carlo (DSMC) method is applied in this paper to the study of rarefied, hypersonic, reentry flows. The assumptions and simplifications involved with the treatment of ionization, free electrons and the electric field are investigated. A new method is presented for the calculation of the electric field and handling of charged particles with DSMC. In addition, a two-step model for electron impact ionization is implemented. The flow field representing a 10 km/sec shock at an altitude of 65 km is calculated. The effects of the new modeling techniques on the calculation results are presented and discussed.

An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones.

PubMed

Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

2015-12-11

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel "quasi-dynamic" Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the "process-level" fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move.

Signature of charge migration in modulations of double ionization

NASA Astrophysics Data System (ADS)

Mauger, François; Abanador, Paul M.; Bruner, Adam; Sissay, Adonay; Gaarde, Mette B.; Lopata, Kenneth; Schafer, Kenneth J.

2018-04-01

We present a theoretical investigation of charge migration following strong-field ionization in a multielectron system. We study a model homonuclear molecule with two electrons, each restricted to one dimension (1 +1 D ), interacting with a strong, static electric field. We show that in this system charge migration results from the interplay between multiple ionization channels that overlap in space, creating a coherent electron-hole wave packet in the cation. We also find that, in our case, charge migration following the first ionization manifests as a modulation of the subsequent double-ionization signal. We derive a parametrized semiclassical model from the full multielectron system and we discuss the importance of the choice of cation electronic-structure basis for the efficacy of the semiclassical representation. We use the ab initio solution of the full 1 +1 D system as a reference for the qualitative and quantitative results of the parametrized semiclassical model. We discuss the extension of our model to long-wavelength time-dependent fields with full-dimension, many-electron targets.

Ionization in the local interstellar and intergalactic media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, K.

1990-01-01

Detailed photoionization calculations for the local interstellar medium (LISM) and the intergalactic medium (IGM) are presented. Constraints in the LISM are imposed by H I column density derived from IUE and Copernicus data toward nearby B stars and hot white dwarfs. The EUV radiation field is modeled including contributions from discrete stellar sources and from a thermal bremsstrahlung-radiative recombination spectrum emitted from the surrounding 10(exp 6) K coronal substrate. Lower limits to the fractional ionization of hydrogen and helium of 0.17 and 0.30 respectively are established. The derived limits have important implications for the interpretation of the H I andmore » He I backscattering results. The high He ionization fraction results primarily from very strong line emission below 500 A originating in the surrounding coronal substrate while the H ionization is dominated by the EUV radiation from the discrete stellar sources. The dual effects of thermal conduction and the EUV spectrum of the 10(exp 6) K plasma on ionization in the cloud skin are explored. The EUV radiation field and Auger ionization have insignificant effects on the resulting ionic column densities of Si IV, C IV, N V and O VI through the cloud skin. Calculations show that the abundances of these species are dominated by collisional ionization in the thermal conduction front. Because of a low charge exchange rate with hydrogen, the ionic column density ratios of N(C III)/N(C II) and N(N II)/N(N I) are dominated by the EUV radiation field in the local interstellar medium. These ratios should be important diagnostics for the EUV radiation field and serve as surrogate indicators of the interstellar He and H ionization fraction respectively. The same photoionization model is applied to the intergalactic medium.« less

L. V. Keldysh’s “Ionization in the Field of a Strong Electromagnetic Wave” and modern physics of atomic interaction with a strong laser field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedorov, M. V., E-mail: fedorov@gmail.com

2016-03-15

Basic premises, approximations, and results of L.V. Keldysh’s 1964 work on multiphoton ionization of atoms are discussed, as well as its influence on the modern science of the interaction of atomic–molecular systems with a strong laser field.

Effects of repeated restraint stress and WiFi signal exposure on behavior and oxidative stress in rats.

PubMed

Othman, Haifa; Ammari, Mohamed; Sakly, Mohsen; Abdelmelek, Hafedh

2017-10-01

Today, due to technology development and aversive events of daily life, Human exposure to both radiofrequency and stress is unavoidable. This study investigated the co-exposure to repeated restraint stress and WiFi signal on cognitive function and oxidative stress in brain of male rats. Animals were divided into four groups: Control, WiFi-exposed, restrained and both WiFi-exposed and restrained groups. Each of WiFi exposure and restraint stress occurred 2 h (h)/day during 20 days. Subsequently, various tests were carried out for each group, such as anxiety in elevated plus maze, spatial learning abilities in the water maze, cerebral oxidative stress response and cholinesterase activity in brain and serum. Results showed that WiFi exposure and restraint stress, alone and especially if combined, induced an anxiety-like behavior without impairing spatial learning and memory abilities in rats. At cerebral level, we found an oxidative stress response triggered by WiFi and restraint, per se and especially when combined as well as WiFi-induced increase in acetylcholinesterase activity. Our results reveal that there is an impact of WiFi signal and restraint stress on the brain and cognitive processes especially in elevated plus maze task. In contrast, there are no synergistic effects between WiFi signal and restraint stress on the brain.

Dietary Fiber Supplementation for Fecal Incontinence: A Randomized Clinical Trial

PubMed Central

Bliss, Donna Z.; Savik, Kay; Jung, Hans-Joachim G.; Whitebird, Robin; Lowry, Ann; Sheng, Xioayan

2014-01-01

Dietary fiber supplements are used to manage fecal incontinence (FI), but little is known about the fiber type to recommend or the level of effectiveness of such supplements, which appear related to the fermentability of the fiber. The aim of this single-blind, randomized controlled trial was to compare the effects of three dietary fiber supplements (carboxymethylcellulose [CMC], gum arabic [GA], or psyllium) with differing levels of fermentability to a placebo in community-living individuals incontinent of loose/liquid feces. The primary outcome was FI frequency; secondary outcomes included FI amount and consistency, supplement intolerance, and quality of life (QoL). Possible mechanisms underlying supplement effects were also examined. After a 14-day baseline, 189 subjects consumed a placebo or 16g total fiber/day of one of the fiber supplements for 32 days. FI frequency significantly decreased after psyllium supplementation versus placebo, in both intent-to-treat and per-protocol mixed model analyses. CMC increased FI frequency. In intent-to-treat analysis, the number of FI episodes/week after supplementation was estimated to be 5.5 for Placebo, 2.5 for Psyllium, 4.3 for GA, and 6.2 for CMC. Only psyllium consumption resulted in a gel in feces. Supplement intolerance was low. QoL scores did not differ among groups. Patients with FI may experience a reduction in FI frequency after psyllium supplementation, and decreased FI frequency has been shown to be an important personal goal of treatment for patients with FI. Formation of a gel in feces appears to be a mechanism by which residual psyllium improved FI. PMID:25155992

Measurements of the time constant for steady ionization in shaped-charge barium releases

NASA Technical Reports Server (NTRS)

Hoch, Edward L.; Hallinan, Thomas J.

1993-01-01

Quantitative measurements of three solar illuminated shaped-charge barium releases injected at small angles to the magnetic field were made using a calibrated color television camera. Two of the releases were from 1989. The third release, a reanalysis of an event included in Hallinan's 1988 study of three 1986 releases, was included to provide continuity between the two studies. Time constants for ionization, measured during the first 25 s of each release, were found to vary considerably. The two 1989 time constants differed substantially, and both were significantly less than any of the 1986 time constants. On the basis of this variability, we conclude that the two 1989 releases showed evidence of continuous nonsolar ionization. One release showed nonsolar ionization which could not he attributed to Alfven's critical ionization velocity process, which requires a component of velocity perpendicular to the magnetic field providing a perpendicular energy greater than the ionization potential.

Threats to ultra-high-field MRI

NASA Astrophysics Data System (ADS)

Le Bihan, Denis

2009-08-01

In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are necessary to prevent workers from suffering any undue acute health effects. But although not initially intended, the biggest impact of the directive could be on magnetic resonance imaging (MRI), which is used in hospitals worldwide to produce images of unrivalled quality of the brain and other soft tissues.

Forensic applications of ambient ionization mass spectrometry.

PubMed

Ifa, Demian R; Jackson, Ayanna U; Paglia, Giuseppe; Cooks, R Graham

2009-08-01

This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques--to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin--are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents.

Synchronization and long-time memory in neural networks with inhibitory hubs and synaptic plasticity

NASA Astrophysics Data System (ADS)

Bertolotti, Elena; Burioni, Raffaella; di Volo, Matteo; Vezzani, Alessandro

2017-01-01

We investigate the dynamical role of inhibitory and highly connected nodes (hub) in synchronization and input processing of leaky-integrate-and-fire neural networks with short term synaptic plasticity. We take advantage of a heterogeneous mean-field approximation to encode the role of network structure and we tune the fraction of inhibitory neurons fI and their connectivity level to investigate the cooperation between hub features and inhibition. We show that, depending on fI, highly connected inhibitory nodes strongly drive the synchronization properties of the overall network through dynamical transitions from synchronous to asynchronous regimes. Furthermore, a metastable regime with long memory of external inputs emerges for a specific fraction of hub inhibitory neurons, underlining the role of inhibition and connectivity also for input processing in neural networks.

Holography of Wi-fi Radiation.

PubMed

Holl, Philipp M; Reinhard, Friedemann

2017-05-05

Wireless data transmission systems such as wi-fi or Bluetooth emit coherent light-electromagnetic waves with a precisely known amplitude and phase. Propagating in space, this radiation forms a hologram-a two-dimensional wave front encoding a three-dimensional view of all objects traversed by the light beam. Here we demonstrate a scheme to record this hologram in a phase-coherent fashion across a meter-sized imaging region. We recover three-dimensional views of objects and emitters by feeding the resulting data into digital reconstruction algorithms. Employing a digital implementation of dark-field propagation to suppress multipath reflection, we significantly enhance the quality of the resulting images. We numerically simulate the hologram of a 10-m-sized building, finding that both localization of emitters and 3D tomography of absorptive objects could be feasible by this technique.

Holography of Wi-fi Radiation

NASA Astrophysics Data System (ADS)

Holl, Philipp M.; Reinhard, Friedemann

2017-05-01

Wireless data transmission systems such as wi-fi or Bluetooth emit coherent light—electromagnetic waves with a precisely known amplitude and phase. Propagating in space, this radiation forms a hologram—a two-dimensional wave front encoding a three-dimensional view of all objects traversed by the light beam. Here we demonstrate a scheme to record this hologram in a phase-coherent fashion across a meter-sized imaging region. We recover three-dimensional views of objects and emitters by feeding the resulting data into digital reconstruction algorithms. Employing a digital implementation of dark-field propagation to suppress multipath reflection, we significantly enhance the quality of the resulting images. We numerically simulate the hologram of a 10-m-sized building, finding that both localization of emitters and 3D tomography of absorptive objects could be feasible by this technique.

Field camp: Using traditional methods to train the next generation of petroleum geologists

USGS Publications Warehouse

Puckette, J.O.; Suneson, N.H.

2009-01-01

The summer field camp experience provides many students with their best opportunity to learn the scientific process by making observations and collecting, recording, evaluating, and interpreting geologic data. Field school projects enhance student professional development by requiring cooperation and interpersonal interaction, report writing to communicate interpretations, and the development of project management skills to achieve a common goal. The field school setting provides students with the opportunity to observe geologic features and their spatial distribution, size, and shape that will impact the student's future careers as geoscientists. The Les Huston Geology Field Camp (a.k.a. Oklahoma Geology Camp) near Ca??on City, Colorado, focuses on time-tested traditional methods of geological mapping and fieldwork to accomplish these goals. The curriculum consists of an introduction to field techniques (pacing, orienteering, measuring strike and dip, and using a Jacob's staff), sketching outcrops, section measuring (one illustrating facies changes), three mapping exercises (of increasing complexity), and a field geophysics project. Accurate rock and contact descriptions are emphasized, and attitudes and contacts are mapped in the field. Mapping is done on topographic maps at 1:12,000 and 1:6000 scales; air photos are provided. Global positioning system (GPS)-assisted mapping is allowed, but we insist that locations be recorded in the field and confirmed using visual observations. The course includes field trips to the Cripple Creek and Leadville mining districts, Floris-sant/Guffey volcano area, Pikes Peak batholith, and the Denver Basin. Each field trip is designed to emphasize aspects of geology that are not stressed in the field exercises. Students are strongly encouraged to accurately describe geologic features and gather evidence to support their interpretations of the geologic history. Concise reports are a part of each major exercise. Students are grouped into teams to (1) introduce the team concept and develop interpersonal skills that are fundamental components of many professions, (2) ensure safety, and (3) mix students with varying academic backgrounds and physical strengths. This approach has advantages and disadvantages. Students with academic strengths in specific areas assist those with less experience, thereby becoming engaged in the teaching process. However, some students contribute less to fi nal map projects than others, and assigning grades to individual team members can be diffi cult. The greatest challenges we face involve group dynamics and student personalities. We continue to believe that traditional fi eld methods, aided by (but not relying upon) new technologies, are the key to constructing and/or interpreting geologic maps. The requirement that students document fi eld evidence using careful observations teaches skills that will be benefi cial throughout their professional careers. ??2009 The Geological Society of America. All rights reserved.

Field ionizing elements and applications thereof

NASA Technical Reports Server (NTRS)

Hartley, Frank T. (Inventor)

2003-01-01

A field ionizing element formed of a membrane that houses electrodes therein that are located closer to one another than the mean free path of the gas being ionized. The membrane includes a supporting portion, and a non supporting portion where the ions are formed. The membrane may be used as the front end for a number of different applications including a mass spectrometer, a thruster, an ion mobility element, or an electrochemical device such as a fuel cell.

Impact ionization and transport properties of hexagonal boron nitride in a constant-voltage measurement

NASA Astrophysics Data System (ADS)

Hattori, Yoshiaki; Taniguchi, Takashi; Watanabe, Kenji; Nagashio, Kosuke

2018-01-01

The electrical evaluation of the crystallinity of hexagonal boron nitride (h -BN) is still limited to the measurement of dielectric breakdown strength, in spite of its importance as the substrate for two-dimensional van der Waals heterostructure devices. In this study, physical phenomena for degradation and failure in exfoliated single-crystal h -BN films were investigated using the constant-voltage stress test. At low electrical fields, the current gradually reduced and saturated with time, while the current increased at electrical fields higher than ˜8 MV /cm and finally resulted in the catastrophic dielectric breakdown. These transient behaviors may be due to carrier trapping to the defect sites in h -BN because trapped carriers lower or enhance the electrical fields in h -BN depending on their polarities. The key finding is the current enhancement with time at the high electrical field, suggesting the accumulation of electrons generated by the impact ionization process. Therefore, a theoretical model including the electron generation rate by an impact ionization process was developed. The experimental data support the expected degradation mechanism of h -BN. Moreover, the impact ionization coefficient was successfully extracted, which is comparable to that of Si O2 , even though the fundamental band gap for h -BN is smaller than that for Si O2 . Therefore, the dominant impact ionization in h -BN could be band-to-band excitation, not defect-assisted impact ionization.

Avalanche multiplication and impact ionization in amorphous selenium photoconductive target

NASA Astrophysics Data System (ADS)

Park, Wug-Dong; Tanioka, Kenkichi

2014-03-01

The avalanche multiplication factor and the hole ionization coefficient in the amorphous selenium (a-Se) high-gain avalanche rushing amorphous photoconductor (HARP) target depend on the electric field. The phenomenon of avalanche multiplication and impact ionization in the 0.4-µm-thick a-Se HARP target is investigated. The hot carrier energy in the 0.4-µm-thick a-Se HARP target increases linearly as the target voltage increases. The energy relaxation length of hot carriers in the a-Se photoconductor of the 0.4-µm-thick HARP target saturates as the electric field increases. The average energy Eav of a hot carrier and the energy relaxation length λE in the a-Se photoconductor of the 0.4-µm-thick HARP target at 1 × 108 V/m were 0.25 eV and 2.5 nm, respectively. In addition, the hole ionization coefficient β and the avalanche multiplication factor M are derived as a function of the electric field, the average energy of a hot carrier, and the impact ionization energy. The experimental hole ionization coefficient β and the avalanche multiplication factor M in the 0.4-µm-thick a-Se HARP target agree with the theoretical results.

20-Gbps optical LiFi transport system.

PubMed

Ying, Cheng-Ling; Lu, Hai-Han; Li, Chung-Yi; Cheng, Chun-Jen; Peng, Peng-Chun; Ho, Wen-Jeng

2015-07-15

A 20-Gbps optical light-based WiFi (LiFi) transport system employing vertical-cavity surface-emitting laser (VCSEL) and external light injection technique with 16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) modulating signal is proposed. Good bit error rate (BER) performance and clear constellation map are achieved in our proposed optical LiFi transport systems. An optical LiFi transport system, delivering 16-QAM-OFDM signal over a 6-m free-space link, with a data rate of 20 Gbps, is successfully demonstrated. Such a 20-Gbps optical LiFi transport system provides the advantage of a free-space communication link for high data rates, which can accelerate the visible laser light communication (VLLC) deployment.

Geomagnetism-Aided Indoor Wi-Fi Radio-Map Construction via Smartphone Crowdsourcing.

PubMed

Li, Wen; Wei, Dongyan; Lai, Qifeng; Li, Xianghong; Yuan, Hong

2018-05-08

Wi-Fi radio-map construction is an important phase in indoor fingerprint localization systems. Traditional methods for Wi-Fi radio-map construction have the problems of being time-consuming and labor-intensive. In this paper, an indoor Wi-Fi radio-map construction method is proposed which utilizes crowdsourcing data contributed by smartphone users. We draw indoor pathway map and construct Wi-Fi radio-map without requiring manual site survey, exact floor layout and extra infrastructure support. The key novelty is that it recognizes road segments from crowdsourcing traces by a cluster based on magnetism sequence similarity and constructs an indoor pathway map with Wi-Fi signal strengths annotated on. Through experiments in real world indoor areas, the method is proved to have good performance on magnetism similarity calculation, road segment clustering and pathway map construction. The Wi-Fi radio maps constructed by crowdsourcing data are validated to provide competitive indoor localization accuracy.

Geomagnetism-Aided Indoor Wi-Fi Radio-Map Construction via Smartphone Crowdsourcing

PubMed Central

Li, Wen; Wei, Dongyan; Lai, Qifeng; Li, Xianghong; Yuan, Hong

2018-01-01

Wi-Fi radio-map construction is an important phase in indoor fingerprint localization systems. Traditional methods for Wi-Fi radio-map construction have the problems of being time-consuming and labor-intensive. In this paper, an indoor Wi-Fi radio-map construction method is proposed which utilizes crowdsourcing data contributed by smartphone users. We draw indoor pathway map and construct Wi-Fi radio-map without requiring manual site survey, exact floor layout and extra infrastructure support. The key novelty is that it recognizes road segments from crowdsourcing traces by a cluster based on magnetism sequence similarity and constructs an indoor pathway map with Wi-Fi signal strengths annotated on. Through experiments in real world indoor areas, the method is proved to have good performance on magnetism similarity calculation, road segment clustering and pathway map construction. The Wi-Fi radio maps constructed by crowdsourcing data are validated to provide competitive indoor localization accuracy. PMID:29738454

Optical field ionization of atoms and ions using ultrashort laser pulses

NASA Astrophysics Data System (ADS)

Fittinghoff, D. N.

1993-12-01

This dissertation research is an investigation of the strong optical field ionization of atoms and ions by 120-fs, 614-run laser pulses and 130-fs, 800-nm laser pulses. The experiments have shown ionization that is enhanced above the predictions of sequential tunneling models for He(+2), Ne(+2), and Ar(+2). The ion yields for He(+1), Ne(sup +1) and Ar(sup +1) agree well with the theoretical predictions of optical tunneling models. Investigation of the polarization dependence of the ionization indicates that the enhancements are consistent with a nonsequential ionization mechanism in which the linearly polarized field drives the electron wavefunction back toward the ion core and causes double ionization through inelastic e-2e scattering. These investigations have initiated a number of other studies by other groups and are of current scientific interest in the fields of high-irradiance laser-matter interactions and production of high-density plasmas. This work involved the following: (1) Understanding the characteristic nature of the ion yields produced by tunneling ionization through investigation of analytic solutions for tunneling at optical frequencies. (2) Extensive characterization of the pulses produced by 614-nm and 800-ran ultrashort pulse lasers. Absolute calibration of the irradiance scale produced shows the practicality of the inverse problem--measuring peak laser irradiance using ion yields. (3) Measuring the ion yields for three noble gases using linear, circular and elliptical polarizations of laser pulses at 614-nm and 800-nm. The measurements are some of the first measurements for pulse widths as low as 120-fs.

Testing Earthquake Links in Mexico From 1978 to the 2017 M = 8.1 Chiapas and M = 7.1 Puebla Shocks

NASA Astrophysics Data System (ADS)

Segou, Margarita; Parsons, Tom

2018-01-01

The M = 8.1 Chiapas and the M = 7.1 Puebla earthquakes occurred in the bending part of the subducting Cocos plate 11 days and 600 km apart, a range that puts them well outside the typical aftershock zone. We find this to be a relatively common occurrence in Mexico, with 14% of M > 7.0 earthquakes since 1900 striking more than 300 km apart and within a 2 week interval, not different from a randomized catalog. We calculate the triggering potential caused by crustal stress redistribution from large subduction earthquakes over the last 40 years. There is no evidence that static stress transfer or dynamic triggering from the 8 September Chiapas earthquake promoted the 19 September earthquake. Both recent earthquakes were promoted by past thrust events instead, including delayed afterslip from the 2012 M = 7.5 Oaxaca earthquake. A repeated pattern of shallow thrust events promoting deep intraslab earthquakes is observed over the past 40 years.

Wifi-friendly building, enabling wifi signal indoor: an initial study

NASA Astrophysics Data System (ADS)

Suherman; Mubarakah, Naemah; Sagala, Romulo S.; Prayitno, Hendra

2018-03-01

The 802.11 network (wireless fidelity/WiFi) is the most common wireless infrastructure applied for internet access indoor. Widespread devices and installation simplicity make it better than similar technologies such as 802.16 and other 802.xx series. The access points are the most influential devices for indoor access. However, building indoor architectures contribute to the signal quality. Since WiFi installation in buildings becomes prevalent, the architecture should consider WiFi-friendliness into consideration. The more friendly the building to WiFi signal, the more efficient the 802.11 based wireless infrastructure. This paper present preliminary study how the building, specially the obstacle material, effects the WiFi signal propagation indoor. The study was performed by using ESP8266-based WiFi signal reader, to determine the impact indoor obstacles to WiFi signal propagation. The initial study shows that simple reflecting materials increase signal level about 1.14 dBm. WiFi-friendly building can be achieved by transforming building properties into signal interconnector. A simple photo frame with aluminium sheet insertion increase signal level on the second floor up to 6.56dBm.

Adaptation of Timing Behavior to a Regular Change in Criterion

PubMed Central

Sanabria, Federico; Oldenburg, Liliana

2013-01-01

This study examined how operant behavior adapted to an abrupt but regular change in the timing of reinforcement. Pigeons were trained on a fixed interval (FI) 15-s schedule of reinforcement during half of each experimental session, and on an FI 45-s (Experiment 1), FI 60-s (Experiment 2), or extinction schedule (Experiment 3) during the other half. FI performance was well characterized by a mixture of two gamma-shaped distributions of responses. When a longer FI schedule was in effect in the first half of the session (Experiment 1), a constant interference by the shorter FI was observed. When a shorter FI schedule was in effect in the first half of the session (Experiments 1, 2, and 3), the transition between schedules involved a decline in responding and a progressive rightward shift in the mode of the response distribution initially centered around the short FI. These findings are discussed in terms of the constraints they impose to quantitative models of timing, and in relation to the implications for information-based models of associative learning. PMID:23962672

Loading Rate Variations Along a Midcrustal Shear Zone Preceding the Mw6.0 Earthquake of 24 August 2016 in Central Italy

NASA Astrophysics Data System (ADS)

Vuan, A.; Sugan, M.; Chiaraluce, L.; Di Stefano, R.

2017-12-01

To identify greater detail in the seismicity pattern preceding the 24 August 2016 Mw6.0 earthquake in Central Italy, we apply waveform matching using 1,028 events as templates. In the 8 months before the mainshock, we find 2,000 additional earthquakes mostly located along a subhorizontal shear zone (SZ) bounding at depth the extensional fault system. Asynchrony is observed in the occurrence of events nucleating along the SZ compared to the ones on fault portions embedded in the shallower upper crust, with the former anticipating the latter. Within the SZ, we also observe along-strike seismic migration episodes with earthquakes pointing toward the Mw6.0 mainshock nucleation zone. These episodes are followed by an apparent quiescence within the main fault area. We suggest that the variations in the seismic activity along the SZ represent the brittle signature of the tectonic loading process enabling portions of the overlaying normal faults to become unlocked.

An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones

PubMed Central

Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

2015-01-01

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel “quasi-dynamic” Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the “process-level” fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move. PMID:26690447

Translating Policy to Practice: Initiating RTI in Urban Schools

ERIC Educational Resources Information Center

Dougherty Stahl, Katherine A.; Keane, Annette E.; Simic, Ognjen

2013-01-01

This mixed methods study explores the pilot implementation of a Response to Intervention framework in the first grade classrooms in three urban schools. Two schools in a fully implemented condition (FI) with a facilitator and a partially implemented condition (PI) without a facilitator were investigated using student achievement data, field notes,…

Sensitivity of the vitellogenin assay to diagnose exposure of fathead minnows to 17α-ethynylestradiol

EPA Science Inventory

Vitellogenin is frequently used as a biomarker of exposure to environmental estrogens. When designing an experiment using vitellogenin, investigators must decide whether to deploy fish in the field or expose fish in the lab, how many fish to expose, and how long to expose the fi...

Interfacial exchange coupling and magnetization reversal in perpendicular [Co/Ni]N/TbCo composite structures.

PubMed

Tang, M H; Zhang, Zongzhi; Tian, S Y; Wang, J; Ma, B; Jin, Q Y

2015-06-15

Interfacial exchange coupling and magnetization reversal characteristics in the perpendicular heterostructures consisting of an amorphous ferrimagnetic (FI) TbxCo(100-x) alloy layer exchange-coupled with a ferromagnetic (FM) [Co/Ni]N multilayer have been investigated. As compared with pure TbxCo(100-x) alloy, the magnetization compensation composition of the heterostructures shift to a higher Tb content, implying Co/Ni also serves to compensate the Tb moment in TbCo layer. The net magnetization switching field Hc⊥ and interlayer interfacial coupling field Hex, are not only sensitive to the magnetization and thickness of the switched TbxCo(100-x) or [Co/Ni]N layer, but also to the perpendicular magnetic anisotropy strength of the pinning layer. By tuning the layer structure we achieve simultaneously both large Hc⊥ = 1.31 T and Hex = 2.19 T. These results, in addition to the fundamental interest, are important to understanding of the interfacial coupling interaction in the FM/FI heterostructures, which could offer the guiding of potential applications in heat-assisted magnetic recording or all-optical switching recording technique.

Food Insecurity and the Negative Impact on Brazilian Children's Health-Why Does Food Security Matter for Our Future Prosperity? Brazilian National Survey (PNDS 2006/07).

PubMed

Poblacion, Ana Paula; Cook, John T; Marín-León, Leticia; Segall-Corrêa, Ana Maria; Silveira, Jonas A C; Konstantyner, Tulio; Taddei, José Augusto A C

2016-12-01

Food insecurity (FI) refers to limited or uncertain access to food resulting from financial constraints. Numerous studies have shown association between FI and adverse health outcomes among adults and children around the world, but in Brazil, such information is scarce, especially if referring to nationally representative information. To test for an independent association between FI and health outcomes. Most recent Brazilian Demographic and Health Survey using nationally representative complex probability sampling. Participants were 3923 children <5 years of age, each representing a household. Data from the validated Brazilian Food Insecurity Scale were dichotomized as food secure (food security/mild FI) or food insecure (moderate FI/severe FI). Poisson regression was used to test for associations between FI and various health indicators. Models adjusted for socioeconomic and demographic variables showed that children hospitalized for pneumonia or diarrhea were 30% more prevalent in FI households (adjusted prevalence ratio [aPR]: 1.3; 1.1-1.6). Underweight children were 40% more prevalent in FI households (aPR: 1.4; 1.1-1.7). Children who didn't eat meat and fruits and vegetables every day were 20% and 70% more prevalent in FI households (aPR: 1.2; 1.1-1.4 and aPR: 1.7; 1.3-2.3), respectively. Children who grow up in food-insecure households have been shown to have worse health conditions than those in food-secure households. Consequently, their human capital accumulation and work-life productivity are likely to be reduced in the future, leading them into adulthood less capable of generating sufficient income, resulting in a cycle of intergenerational poverty and FI. © The Author(s) 2016.

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

NASA Astrophysics Data System (ADS)

Weber, T. E.; Intrator, T. P.; Smith, R. J.

2015-04-01

Injection of plasma via an annular array of coaxial plasma guns during the pre-ionization phase of field-reversed configuration (FRC) formation is shown to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. This approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ˜350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densities and higher temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.

Vortex focusing of ions produced in corona discharge.

PubMed

Kolomiets, Yuri N; Pervukhin, Viktor V

2013-06-15

Completeness of the ion transportation into an analytical path defines the efficiency of ionization analysis techniques. This is of particular importance for atmospheric pressure ionization sources like corona discharge, electrospray, ionization with radioactive ((3)H, (63)Ni) isotopes that produce nonuniform spatial distribution of sample ions. The available methods of sample ion focusing are either efficient at reduced pressure (~1Torr) or feature high sample losses. This paper deals with experimental research into atmospheric pressure focusing of unipolar (positive) ions using a highly swirled air stream with a well-defined vortex core. Effects of electrical fields from corona needle and inlet capillary of mass spectrometer on collection efficiency is considered. We used a corona discharge to produce an ionized unipolar sample. It is shown experimentally that with an electrical field barrier efficient transportation and focusing of an ionized sample are possible only when a metal plate restricting the stream and provided with an opening covered with a grid is used. This gives a five-fold increase of the transportation efficiency. It is shown that the electric field barrier in the vortex sampling region reduces the efficiency of remote ionized sample transportation two times. The difference in the efficiency of light ion focusing observed may be explained by a high mobility and a significant effect of the electric field barrier upon them. It is possible to conclude based on the experimental data that the presence of the field barrier narrows considerably (more than by one and half) the region of the vortex sample ion focusing. Copyright © 2013 Elsevier B.V. All rights reserved.

Efficient pre-ionization by direct X-B mode conversion in VEST

NASA Astrophysics Data System (ADS)

Jo, JongGab; Lee, H. Y.; Kim, S. C.; Kim, S. H.; An, Y. H.; Hwang, Y. S.

2017-01-01

Pre-ionization experiments with pure toroidal field have been carried out in VEST (Versatile Experiment Spherical Torus) to investigate the feasibility of direct XB mode conversion from perpendicular LFS (Low Field Side) injection for efficient pre-ionization. Pre-ionization plasmas are studied by measuring the electron density and temperature profiles with respect to microwave power and toroidal field strength, and 2D full wave cold plasma simulation using the COMSOL Multiphysics is performed for the comparison. It is experimentally figured out that exceeding the threshold microwave power (>3 kW), the parametric decay and localized collisional heating is observed near the UHR (Upper Hybrid Resonance), and the efficient XB mode conversion can be achieved in both short density scale length (Ln) and magnetic scale length (LB) region positioned at outboard and inboard sides, respectively. From the 2D full wave simulations, the reflection and tunneling of X-wave near the R-cutoff layer according to the measured electron density profiles are analyzed with electric field polarization and power flow. Threshold electric field and wave power density for parametric decay are evaluated at least more than 4.8 × 104 V/m and 100 W/cm2, respectively. This study shows that efficient pre-ionization schemes using direct XB mode conversion can be realized by considering the key factors such as Ln, LB, and transmitted wave power at the UHR. Application to Ohmic start-up experiment is carried out to confirm the effect of the pre-ionization schemes on tokamak plasma start-up in VEST.

Circumstances of fall-related injuries by age and gender among community-dwelling adults in the United States

PubMed Central

Timsina, Lava R.; Willetts, Joanna L.; Brennan, Melanye J.; Marucci-Wellman, Helen; Lombardi, David A.; Courtney, Theodore K.; Verma, Santosh K.

2017-01-01

Introduction Falls are the leading cause of injury in almost all age-strata in the U.S. However, fall-related injuries (FI) and their circumstances are under-studied at the population level, particularly among young and middle-aged adults. This study examined the circumstances of FI among community-dwelling U.S. adults, by age and gender. Methods Narrative texts of FI from the National Health Interview Survey (1997–2010) were coded using a customized taxonomy to assess place, activity, initiating event, hazards, contributing factors, fall height, and work-relatedness of FI. Weighted proportions and incidence rates of FI were calculated across six age-gender groups (18–44, 45–64, 65+ years; women, men). Results The proportion of FI occurring indoors increased with age in both genders (22%, 30%, and 48% among men, and 40%, 49% and 62% among women for 18–44, 45–64, 65+ age-groups, respectively). In each age group the proportion of indoor FI was higher among women as compared to men. Among women, using the stairs was the second leading activity (after walking) at the time of FI (19%, 14% and 10% for women in 18–44, 45–64, 65+ age groups, respectively). FI associated with tripping increased with age among both genders, and women were more likely to trip than men in every age group. Of all age-gender groups, the rate of FI while using ladders was the highest among middle-aged men (3.3 per 1000 person-year, 95% CI 2.0, 4.5). Large objects, stairs and steps, and surface contamination were the three most common hazards noted for 15%, 14% and 13% of fall-related injuries, respectively. Conclusions The rate and the circumstances of FI differ by age and gender. Understanding these differences and obtaining information about circumstances could be vital for developing effective interventions to prevent falls and FI. PMID:28472065

Electromagnetic radiation (Wi-Fi) and epilepsy induce calcium entry and apoptosis through activation of TRPV1 channel in hippocampus and dorsal root ganglion of rats.

PubMed

Ghazizadeh, Vahid; Nazıroğlu, Mustafa

2014-09-01

Incidence rates of epilepsy and use of Wi-Fi worldwide have been increasing. TRPV1 is a Ca(2+) permeable and non-selective channel, gated by noxious heat, oxidative stress and capsaicin (CAP). The hyperthermia and oxidant effects of Wi-Fi may induce apoptosis and Ca(2+) entry through activation of TRPV1 channel in epilepsy. Therefore, we tested the effects of Wi-Fi (2.45 GHz) exposure on Ca(2+) influx, oxidative stress and apoptosis through TRPV1 channel in the murine dorsal root ganglion (DRG) and hippocampus of pentylentetrazol (PTZ)-induced epileptic rats. Rats in the present study were divided into two groups as controls and PTZ. The PTZ groups were divided into two subgroups namely PTZ + Wi-Fi and PTZ + Wi-Fi + capsazepine (CPZ). The hippocampal and DRG neurons were freshly isolated from the rats. The DRG and hippocampus in PTZ + Wi-Fi and PTZ + Wi-Fi + CPZ groups were exposed to Wi-Fi for 1 hour before CAP stimulation. The cytosolic free Ca(2+), reactive oxygen species production, apoptosis, mitochondrial membrane depolarization, caspase-3 and -9 values in hippocampus were higher in the PTZ group than in the control although cell viability values decreased. The Wi-Fi exposure induced additional effects on the cytosolic Ca(2+) increase. However, pretreatment of the neurons with CPZ, results in a protection against epilepsy-induced Ca(2+) influx, apoptosis and oxidative damages. In results of whole cell patch-clamp experiments, treatment of DRG with Ca(2+) channel antagonists [thapsigargin, verapamil + diltiazem, 2-APB, MK-801] indicated that Wi-Fi exposure induced Ca(2+) influx via the TRPV1 channels. In conclusion, epilepsy and Wi-Fi in our experimental model is involved in Ca(2+) influx and oxidative stress-induced hippocampal and DRG death through activation of TRPV1 channels, and negative modulation of this channel activity by CPZ pretreatment may account for the neuroprotective activity against oxidative stress.

Food insecurity and Mediterranean diet adherence among Greek university students.

PubMed

Theodoridis, X; Grammatikopoulou, M G; Gkiouras, K; Papadopoulou, S E; Agorastou, T; Gkika, I; Maraki, M I; Dardavessis, T; Chourdakis, M

2018-05-01

To assess Mediterranean diet (MD) adherence and food insecurity (FI) among university students in Greece. A non-probability sample of 236 students was recruited from Athens and Thessaloniki during 2016. FI was assessed with the Household Food Insecurity Access Scale and MD adherence with the MEDAS questionnaire. Mean MEDAS score of the sample was 6.4 ± 1.9, with women demonstrating greater MD adherence compared to men (p = 0.016) and Dietetics students exhibiting increased score compared to the rest (p ≤ 0.001). A low proportion of participants were food-secure (17.8%), 45.3% were severely food-insecure, 22.0% experienced moderate FI and the remaining 14.8% had low FI. Participants studying in the city they grew up exhibited lower FI compared to those studying in other cities (p = 0.009), while, additionally, a trend was noted for increased FI among students with an unemployed family member (p = 0.05). Students working night shifts had lower MD adherence and increased FI compared to the rest (p = 0.004 and p = 0.003, respectively). The same pattern was observed among participants who smoked (p = 0.003 for MD adherence and p = 0.009 for FI, respectively). Multivariate regression analyses did not reveal any connections between FI categories, waist circumference or BMI, but showed an inverse relationship between severe FI and MD adherence. The majority of the surveyed university students from Greece demonstrate some degree of FI, with a great proportion being severely food-insecure. Increased FI is inversely associated with MD adherence. Copyright © 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data

NASA Astrophysics Data System (ADS)

Song, Xia; Hoffman, Forrest M.; Iversen, Colleen M.; Yin, Yunhe; Kumar, Jitendra; Ma, Chun; Xu, Xiaofeng

2017-09-01

Earth system models (ESMs) have been widely used for projecting global vegetation carbon dynamics, yet how well ESMs performed for simulating vegetation carbon density remains untested. We compiled observational data of vegetation carbon density from literature and existing data sets to evaluate nine ESMs at site, biome, latitude, and global scales. Three variables—root (including fine and coarse roots), total vegetation carbon density, and the root:total vegetation carbon ratios (R/T ratios), were chosen for ESM evaluation. ESM models performed well in simulating the spatial distribution of carbon densities in root (r = 0.71) and total vegetation (r = 0.62). However, ESM models had significant biases in simulating absolute carbon densities in root and total vegetation biomass across the majority of land ecosystems, especially in tropical and arctic ecosystems. Particularly, ESMs significantly overestimated carbon density in root (183%) and total vegetation biomass (167%) in climate zones of 10°S-10°N. Substantial discrepancies between modeled and observed R/T ratios were found: the R/T ratios from ESMs were relatively constant, approximately 0.2 across all ecosystems, along latitudinal gradients, and in tropic, temperate, and arctic climatic zones, which was significantly different from the observed large variations in the R/T ratios (0.1-0.8). There were substantial inconsistencies between ESM-derived carbon density in root and total vegetation biomass and the R/T ratio at multiple scales, indicating urgent needs for model improvements on carbon allocation algorithms and more intensive field campaigns targeting carbon density in all key vegetation components.

SpO2/FiO2 ratio on hospital admission is an indicator of early acute respiratory distress syndrome development among patients at risk.

PubMed

Festic, Emir; Bansal, Vikas; Kor, Daryl J; Gajic, Ognjen

2015-05-01

Oxygen saturation to fraction of inspired oxygen ratio (SpO(2)/FiO(2)) has been validated as a surrogate marker for partial pressure of oxygen to fraction of inspired oxygen ratio among mechanically ventilated patients with acute respiratory distress syndrome (ARDS). The validity of SpO(2)/FiO(2) measurements in predicting ARDS has not been studied. Recently, a Lung Injury Prediction Score (LIPS) has been developed to help identify patients at risk of developing ARDS. This was a secondary analysis of the LIPS-1 cohort. A multivariate logistic regression included all established variables for LIPS, Acute Physiology and Chronic Health Evaluation 2, age, and comorbid conditions that could affect SpO(2)/FiO(2). The primary outcome was development of ARDS in the hospital. The secondary outcomes included hospital mortality, hospital day of ARDS development, and hospital day of death. Of the 5584 patients, we evaluated all 4646 with recorded SpO(2)/FiO(2) values. Median SpO(2)/FiO(2) in those who did and did not develop ARDS was 254 (100, 438) and 452 (329, 467), respectively. There was a significant association between SpO(2)/FiO(2) and ARDS (P ≤ .001). The SpO(2)/FiO(2) was found to be an independent predictor of ARDS in a "dose-dependent" manner; for SpO(2)/FiO(2) < 100--odds ratios (OR) 2.49 (1.69-3.64, P < .001), for SpO(2)/FiO(2) 100 < 200--OR 1.75 (1.16-2.58, P = .007), and for SpO(2)/FiO(2) 200 < 300--OR 1.62 (1.06-2.42, P = .025). The discriminatory characteristics of the multivariable model and SpO2/FiO2 as a single variable demonstrated area under the curve (AUC) of 0.81 and AUC of 0.74, respectively. The SpO2/FiO2, measured within the first 6 hours after hospital admission, is an independent indicator of ARDS development among patients at risk. © The Author(s) 2013.

Fluence inhomogeneities due to a ripple filter induced Moiré effect.

PubMed

Ringbæk, Toke Printz; Brons, Stephan; Naumann, Jakob; Ackermann, Benjamin; Horn, Julian; Latzel, Harald; Scheloske, Stefan; Galonska, Michael; Bassler, Niels; Zink, Klemens; Weber, Uli

2015-02-07

At particle therapy facilities with pencil beam scanning, the implementation of a ripple filter (RiFi) broadens the Bragg peak, so fewer energy steps from the accelerator are required for a homogeneous dose coverage of the planning target volume (PTV). However, sharply focusing the scanned pencil beams at the RiFi plane by ion optical settings can lead to a Moiré effect, causing fluence inhomogeneities at the isocenter. This has been experimentally proven at the Heidelberg Ionenstrahl-Therapiezentrum (HIT), Universitätsklinikum Heidelberg, Germany. 150 MeV u(-1) carbon-12 ions are used for irradiation with a 3 mm thick RiFi. The beam is focused in front of and as close to the RiFi plane as possible. The pencil beam width is estimated to be 0.78 mm at a 93 mm distance from the RiFi. Radiographic films are used to obtain the fluence profile 30 mm in front of the isocenter, 930 mm from the RiFi. The Monte Carlo (MC) code SHIELD-HIT12A is used to determine the RiFi-induced inhomogeneities in the fluence distribution at the isocenter for a similar setup, pencil beam widths at the RiFi plane ranging from σχ(RiFi to 1.2 mm and for scanning step sizes ranging from 1.5 to 3.7 mm. The beam application and monitoring system (BAMS) used at HIT is modelled and simulated. When the width of the pencil beams at the RiFi plane is much smaller than the scanning step size, the resulting inhomogeneous fluence distribution at the RiFi plane interfers with the inhomogeneous RiFi mass distribution and fluence inhomogeneity can be observed at the isocenter as large as an 8% deviation from the mean fluence. The inverse of the fluence ripple period at the isocenter is found to be the difference between the inverse of the RiFi period and the inverse of the scanning step size. We have been able to use MC simulations to reproduce the spacing of the ripple stripes seen in films irradiated at HIT. Our findings clearly indicate that pencil beams sharply focused near the RiFi plane result in fluence inhomogeneity at the isocenter. In the normal clinical application, such a setting should generally be avoided.

Risk stratification using SpO2/FiO2 and PEEP at initial ARDS diagnosis and after 24 h in patients with moderate or severe ARDS.

PubMed

Pisani, Luigi; Roozeman, Jan-Paul; Simonis, Fabienne D; Giangregorio, Antonio; van der Hoeven, Sophia M; Schouten, Laura R; Horn, Janneke; Neto, Ary Serpa; Festic, Emir; Dondorp, Arjen M; Grasso, Salvatore; Bos, Lieuwe D; Schultz, Marcus J

2017-10-25

We assessed the potential of risk stratification of ARDS patients using SpO 2 /FiO 2 and positive end-expiratory pressure (PEEP) at ARDS onset and after 24 h. We used data from a prospective observational study in patients admitted to a mixed medical-surgical intensive care unit of a university hospital in the Netherlands. Risk stratification was by cutoffs for SpO 2 /FiO 2 and PEEP. The primary outcome was in-hospital mortality. Patients with moderate or severe ARDS with a length of stay of > 24 h were included in this study. Patients were assigned to four predefined risk groups: group I (SpO 2 /FiO 2  ≥ 190 and PEEP < 10 cm H 2 O), group II (SpO 2 /FiO 2  ≥ 190 and PEEP ≥ 10 cm), group III (SpO 2 /FiO 2  < 190 and PEEP < 10 cm H 2 O) and group IV (SpO 2 /FiO 2  < 190 and PEEP ≥ 10 cm H 2 O). The analysis included 456 patients. SpO 2 /FiO 2 and PaO 2 /FiO 2 had a strong relationship (P < 0.001, R 2  = 0.676) that could be described in a linear regression equation (SpO 2 /FiO 2  = 42.6 + 1.0 * PaO 2 /FiO 2 ). Risk stratification at initial ARDS diagnosis resulted in groups that had no differences in in-hospital mortality. Risk stratification at 24 h resulted in groups with increasing mortality rates. The association between group assignment at 24 h and outcome was confounded by several factors, including APACHE IV scores, arterial pH and plasma lactate levels, and vasopressor therapy. In this cohort of patients with moderate or severe ARDS, SpO 2 /FiO 2 and PaO 2 /FiO 2 have a strong linear relationship. In contrast to risk stratification at initial ARDS diagnosis, risk stratification using SpO 2 /FiO 2 and PEEP after 24 h resulted in groups with worsening outcomes. Risk stratification using SpO 2 /FiO 2 and PEEP could be practical, especially in resource-limited settings.

Field ionization characteristics of an ion source array for neutron generators

NASA Astrophysics Data System (ADS)

Bargsten Johnson, B.; Schwoebel, P. R.; Resnick, P. J.; Holland, C. E.; Hertz, K. L.; Chichester, D. L.

2013-11-01

A new deuterium ion source is being developed to improve the performance of existing compact neutron generators. The ion source is a microfabricated array of metal tips with an integrated gate (i.e., grid) and produces deuterium ions by field ionizing (or field desorbing) a supply of deuterium gas. Deuterium field ion currents from arrays at source temperatures of 77 K and 293 K are studied. Ion currents from single etched-wire tips operating under the same conditions are used to help understand array results. I-F characteristics of the arrays were found to follow trends similar to those of the better understood single etched-wire tip results; however, the fields achieved by the arrays are limited by electrical breakdown of the structure. Neutron production by field ionization at 293 K was demonstrated for the first time from microfabricated array structures with integrated gates.

The importance of Rydberg orbitals in dissociative ionization of small hydrocarbon molecules in intense laser fields.

PubMed

Jochim, Bethany; Siemering, R; Zohrabi, M; Voznyuk, O; Mahowald, J B; Schmitz, D G; Betsch, K J; Berry, Ben; Severt, T; Kling, Nora G; Burwitz, T G; Carnes, K D; Kling, M F; Ben-Itzhak, I; Wells, E; de Vivie-Riedle, R

2017-06-30

Much of our intuition about strong-field processes is built upon studies of diatomic molecules, which typically have electronic states that are relatively well separated in energy. In polyatomic molecules, however, the electronic states are closer together, leading to more complex interactions. A combined experimental and theoretical investigation of strong-field ionization followed by hydrogen elimination in the hydrocarbon series C 2 D 2 , C 2 D 4 and C 2 D 6 reveals that the photofragment angular distributions can only be understood when the field-dressed orbitals rather than the field-free orbitals are considered. Our measured angular distributions and intensity dependence show that these field-dressed orbitals can have strong Rydberg character for certain orientations of the molecule relative to the laser polarization and that they may contribute significantly to the hydrogen elimination dissociative ionization yield. These findings suggest that Rydberg contributions to field-dressed orbitals should be routinely considered when studying polyatomic molecules in intense laser fields.

Impact of local electrostatic field rearrangement on field ionization

NASA Astrophysics Data System (ADS)

Katnagallu, Shyam; Dagan, Michal; Parviainen, Stefan; Nematollahi, Ali; Grabowski, Blazej; Bagot, Paul A. J.; Rolland, Nicolas; Neugebauer, Jörg; Raabe, Dierk; Vurpillot, François; Moody, Michael P.; Gault, Baptiste

2018-03-01

Field ion microscopy allows for direct imaging of surfaces with true atomic resolution. The high charge density distribution on the surface generates an intense electric field that can induce ionization of gas atoms. We investigate the dynamic nature of the charge and the consequent electrostatic field redistribution following the departure of atoms initially constituting the surface in the form of an ion, a process known as field evaporation. We report on a new algorithm for image processing and tracking of individual atoms on the specimen surface enabling quantitative assessment of shifts in the imaged atomic positions. By combining experimental investigations with molecular dynamics simulations, which include the full electric charge, we confirm that change is directly associated with the rearrangement of the electrostatic field that modifies the imaging gas ionization zone. We derive important considerations for future developments of data reconstruction in 3D field ion microscopy, in particular for precise quantification of lattice strains and characterization of crystalline defects at the atomic scale.

PIC simulations of post-pulse field reversal and secondary ionization in nanosecond argon discharges

NASA Astrophysics Data System (ADS)

Kim, H. Y.; Gołkowski, M.; Gołkowski, C.; Stoltz, P.; Cohen, M. B.; Walker, M.

2018-05-01

Post-pulse electric field reversal and secondary ionization are investigated with a full kinetic treatment in argon discharges between planar electrodes on nanosecond time scales. The secondary ionization, which occurs at the falling edge of the voltage pulse, is induced by charge separation in the bulk plasma region. This process is driven by a reverse in the electric field from the cathode sheath to the formerly driven anode. Under the influence of the reverse electric field, electrons in the bulk plasma and sheath regions are accelerated toward the cathode. The electron movement manifests itself as a strong electron current generating high electron energies with significant electron dissipated power. Accelerated electrons collide with Ar molecules and an increased ionization rate is achieved even though the driving voltage is no longer applied. With this secondary ionization, in a single pulse (SP), the maximum electron density achieved is 1.5 times higher and takes a shorter time to reach using 1 kV 2 ns pulse as compared to a 1 kV direct current voltage at 1 Torr. A bipolar dual pulse excitation can increase maximum density another 50%–70% above a SP excitation and in half the time of RF sinusoidal excitation of the same period. The first field reversal is most prominent but subsequent field reversals also occur and correspond to electron temperature increases. Targeted pulse designs can be used to condition plasma density as required for fast discharge applications.

Individual differences in the ability to identify, select and use appropriate frames of reference for perceptuo-motor control.

PubMed

Isableu, B; Ohlmann, T; Cremieux, J; Vuillerme, N; Amblard, B; Gresty, M A

2010-09-01

The causes of the interindividual differences (IDs) in how we perceive and control spatial orientation are poorly understood. Here, we propose that IDs partly reflect preferred modes of spatial referencing and that these preferences or "styles" are maintained from the level of spatial perception to that of motor control. Two groups of experimental subjects, one with high visual field dependency (FD) and one with marked visual field independency (FI) were identified by the Rod and Frame Test, which identifies relative dependency on a visual frame of reference (VFoR). FD and FI subjects were tasked with standing still in conditions of increasing postural difficulty while visual cues of self-orientation (a visual frame tilted in roll) and self-motion (in stroboscopic illumination) were varied and in darkness to assess visual dependency. Postural stability, overall body orientation and modes of segmental stabilization relative to either external (space) or egocentric (adjacent segments) frames of reference in the roll plane were analysed. We hypothesized that a moderate challenge to balance should enhance subjects' reliance on VFoR, particularly in FD subjects, whereas a substantial challenge should constrain subjects to use a somatic-vestibular based FoR to prevent falling in which case IDs would vanish. The results showed that with increasing difficulty, FD subjects became more unstable and more disoriented shown by larger effects of the tilted visual frame on posture. Furthermore, their preference to coalign body/VFoR coordinate systems lead to greater fixation of the head-trunk articulation and stabilization of the hip in space, whereas the head and trunk remained more stabilized in space with the hip fixed on the leg in FI subjects. These results show that FD subjects have difficulties at identifying and/or adopting a more appropriate FoR based on proprioceptive and vestibular cues to regulate the coalignment of posturo/exocentric FoRs. The FI subjects' resistance in the face of altered VFoR and balance challenge resides in their greater ability to coordinate movement by coaligning body axes with more appropriate FoRs (provided by proprioceptive and vestibular co-variance). Copyright (c) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Rotationally resolved pulsed field ionization photoelectron study of CO[sup +](X[sup 2][Sigma][sup +],v[sup +]=0[endash]42) in the energy range of 13. 98[endash]21. 92 eV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, M.; Ng, C.Y.

1999-11-01

We have obtained rotationally resolved pulsed field ionization[endash]photoelectron (PFI-PE) spectra of CO in the energy range of 13.98[endash]21.92 eV, covering the ionization transitions CO[sup +](X hthinsp;[sup 2][Sigma][sup +],v[sup +]=0[endash]42,N[sup +])[l arrow]CO(X hthinsp;[sup 1][Sigma][sup +],v[sup [double prime

Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy

NASA Astrophysics Data System (ADS)

Weilbacher, Peter M.; Monreal-Ibero, Ana; Verhamme, Anne; Sandin, Christer; Steinmetz, Matthias; Kollatschny, Wolfram; Krajnović, Davor; Kamann, Sebastian; Roth, Martin M.; Erroz-Ferrer, Santiago; Marino, Raffaella Anna; Maseda, Michael V.; Wendt, Martin; Bacon, Roland; Dreizler, Stefan; Richard, Johan; Wisotzki, Lutz

2018-04-01

The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae. FITS images and Table of HII regions are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A95 and at http://muse-vlt.eu/science/antennae/

Fixed-Time Schedule Effects in Combination with Response-Dependent Schedules

ERIC Educational Resources Information Center

Borrero, John C.; Bartels-Meints, Jamie A.; Sy, Jolene R.; Francisco, Monica T.

2011-01-01

We evaluated the effects of fixed-interval (FI), fixed-time (FT), and conjoint (combined) FI FT reinforcement schedules on the responding of 3 adults who had been diagnosed with schizophrenia. Responding on vocational tasks decreased for 2 of 3 participants under FT alone relative to FI alone. Responding under FI FT resulted in response…

Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory.

PubMed

Pellegrino, J; Wright, S; Ranvill, J; Amy, G

2005-01-01

Flow-Field Flow Fractionation (FI-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating FI-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide 'ideal' (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with 'real' RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract "effective" characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis-that an analysis of a residence time distribution using FI-FFF can describe 'effective' solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer mass transfer coefficient and the specific resistance of cake or adsorption layers demonstrated that RTD analysis is potentially useful technique to describe colloid properties but requires improvements.

Using the Mini-Session Course Format to Train Students in the Practical Aspects of Modern Mass Spectrometry

ERIC Educational Resources Information Center

Rosado, Dale A., Jr.; Masterson, Tina S.; Masterson, Douglas S.

2011-01-01

Mass spectrometry (MS) has been gaining in popularity in recent years owing in large part to the development of soft-ionization techniques such as matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI). These soft-ionization techniques have opened up the field of MS analysis to biomolecules, polymers, and other high…

Effect of the corrected ionization potential and spatial distribution on the angular and energy distribution in tunnel ionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrović, V. M.; Miladinović, T. B., E-mail: tanja.miladinovic@gmail.com

2016-05-15

Within the framework of the Ammosov–Delone–Krainov theory, we consider the angular and energy distribution of outgoing electrons due to ionization by a circularly polarized electromagnetic field. A correction of the ground ionization potential by the ponderomotive and Stark shift is incorporated in both distributions. Spatial dependence is analyzed.

Pulsed ion beam source

DOEpatents

Greenly, John B.

1997-01-01

An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

Central-cell corrections and shallow donor states in strong magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jayam, Sr. Gerardin; Navaneethakrishnan, K.

2001-06-01

Ionization energies and the central-cell corrections have been calculated for a few shallow donors in Si, GaP, and GaAs. We have assumed a short range potential with two parameters for the strength and the range for each donor, representing the central-cell effects. These parameters are fixed using the experimentally available ionization energies for each donor in a semiconductor. In the presence of a magnetic field the donor ionization energies are estimated using a variational procedure. Our results show that the ionization energies and the central-cell corrections increase with magnetic field. Our results are compared for GaAs with the recent workmore » by Heron et al. [R. J. Heron, R. A. Lewis, P. E. Simmonds, R. P. Starret, A. V. Skougarevsky, R. G. Clark, and C. R. Stanley, J. Appl. Phys. 85, 893 (1999)]. {copyright} 2001 American Institute of Physics.« less

Subcycle dynamics of Coulomb asymmetry in strong elliptical laser fields.

PubMed

Li, Min; Liu, Yunquan; Liu, Hong; Ning, Qicheng; Fu, Libin; Liu, Jie; Deng, Yongkai; Wu, Chengyin; Peng, Liang-You; Peng, Liangyou; Gong, Qihuang

2013-07-12

We measure photoelectron angular distributions of noble gases in intense elliptically polarized laser fields, which indicate strong structure-dependent Coulomb asymmetry. Using a dedicated semiclassical model, we have disentangled the contribution of direct ionization and multiple forward scattering on Coulomb asymmetry in elliptical laser fields. Our theory quantifies the roles of the ionic potential and initial transverse momentum on Coulomb asymmetry, proving that the small lobes of asymmetry are induced by direct ionization and the strong asymmetry is induced by multiple forward scattering in the ionic potential. Both processes are distorted by the Coulomb force acting on the electrons after tunneling. Lowering the ionization potential, the relative contribution of direct ionization on Coulomb asymmetry substantially decreases and Coulomb focusing on multiple rescattering is more important. We do not observe evident initial longitudinal momentum spread at the tunnel exit according to our simulation.

Etiology and management of esophageal food impaction: a population based study.

PubMed

Gretarsdottir, Helga M; Jonasson, Jon Gunnlaugur; Björnsson, Einar S

2015-05-01

Esophageal food impaction (FI) is a common clinical problem with limited information on incidence. Previous population based studies are lacking. The incidence, main etiological factors, recurrence and outcome of FI was determined in the present study in a population based setting. This was a study of consecutive adult patients who presented with FI from 2008 to 2013 at the National University Hospital of Iceland. The mean crude incidence rate of FI was calculated. Retrospective analysis was undertaken on relevant clinical data such as type of bolus, management, complications, recurrence rate, risk factors for recurrence, and outcome. Overall 308 patients had endoscopically confirmed FI, males 199/308 (65%), median age 62 years. The mean crude incidence was 25 per 100,000 inhabitants per year. The types of FI was meat (68%), fish (12%), vegetable (4%) and other food/objects (16%). Causes for the FI included: esophageal strictures (45%), hiatal hernia (22%), eosinophilic esophagitis (EoE) (16%) and esophageal carcinoma (2%). Recurrence appeared in 21%, in which 24/48 (50%) had EoE vs. 40/260 (15%) in others (p = 0.0001). The removal of the foreign body was successful in 98% of the cases during the first endoscopy. Endoscopic associated complications included four (1.3%) aspirations, one (0.3%) esophageal perforation and one Boerhaave syndrome at presentation (both had EoE). The incidence of FI is the highest reported to date. EoE was strongly associated with recurrence of FI. In a population based setting endoscopy is a safe and effective procedure for removing FI.

Fecal Incontinence in Adolescents Is Associated With Child Abuse, Somatization, and Poor Health-related Quality of Life.

PubMed

Rajindrajith, Shaman; Devanarayana, Niranga Manjuri; Benninga, Marc Alexander

2016-05-01

The aim of this study was to evaluate the association between fecal incontinence (FI), child abuse, somatization, and health-related quality of life (HRQoL) in adolescents. Adolescents (ages 13-18 years) were selected from 4 semi-urban schools in the Gampaha district, Sri Lanka. A validated, self-administered questionnaire was used for data collection. FI was defined as at least 1 episode of leakage of feces per month. A total of 1807 adolescents were analyzed (boys 973 [53.8%], mean age 14.4 years, standard deviation [SD] 1.4 years). A total of 47 (2.6%) had FI. Prevalence of sexual abuse (17% vs 2.3% in controls, P < 0.0001), emotional abuse (40.4% vs 22.7%, P < 0.0001), and physical abuse (51% vs 24.3%, P < 0.0001) was significantly higher in children with FI. Adolescents with FI had higher mean somatization scores [mean 20.1, (SD 14.5) vs mean 9.3, (SD 9.2)] compared with those without FI (P < 0.0001). Those with FI also had lower HRQoL scores for physical functioning, social functioning, emotional functioning domains, and performances at school, together with a lower overall HRQoL score compared with those without FI (74.6 vs 87.1, P < 0.0001). There is a significant association between FI and physical, sexual, and emotional abuse. They also have a higher somatization score and a poor HRQoL score in physical, emotional, social, and school functioning domains compared with those without FI.

A limit to frailty in very old, community-dwelling people: a secondary analysis of the Chinese longitudinal health and longevity study.

PubMed

Bennett, Stephanie; Song, Xiaowei; Mitnitski, Arnold; Rockwood, Kenneth

2013-05-01

it has been observed that a frailty index (FI) is limited by the value of 0.7. Whether this holds in countries with higher mortality rates is not known. to test for and quantify a limit in very old Chinese adults and to relate mortality risk to the FI. secondary analysis of four waves (1998, 2000, 2002 and 2005) of the Chinese Longitudinal Health and Longevity Study (CLHLS). a total of 6,300 people from 22 of 31 provinces in China, aged 80-99 years at baseline and followed up to 7 years. an FI was calculated as the ratio of actual to 38 possible health deficits. Frequency distributions were used to evaluate the limit to the FI. Logistic regression and survival analysis were used to evaluate the relationship between the FI and mortality. at each wave, a 99% submaximal limit to frailty was observed at FI = 0.7, despite consecutive losses to death. The death rate for those who were healthiest at baseline (i.e. those in whom the baseline FI = 0) increased from 0.18 at the 2-year follow-up to 0.69 by 7 years. At each wave, 100% mortality at 2 years was observed at FI close to 0.67. A baseline FI >0.45 was associated with 100% 7-year mortality. a limit to frailty occurred with FI = 0.7 which was not exceeded at any age or in any wave. There appears to be a demonstrable limit to the number of health problems that people can tolerate.

Assessment of SMAP soil moisture for global simulation of gross primary production

NASA Astrophysics Data System (ADS)

He, Liming; Chen, Jing M.; Liu, Jane; Bélair, Stéphane; Luo, Xiangzhong

2017-07-01

In this study, high-quality soil moisture data derived from the Soil Moisture Active Passive (SMAP) satellite measurements are evaluated from a perspective of improving the estimation of the global gross primary production (GPP) using a process-based ecosystem model, namely, the Boreal Ecosystem Productivity Simulator (BEPS). The SMAP soil moisture data are assimilated into BEPS using an ensemble Kalman filter. The correlation coefficient (r) between simulated GPP from the sunlit leaves and Sun-induced chlorophyll fluorescence (SIF) measured by Global Ozone Monitoring Experiment-2 is used as an indicator to evaluate the performance of the GPP simulation. Areas with SMAP data in low quality (i.e., forests), or with SIF in low magnitude (e.g., deserts), or both are excluded from the analysis. With the assimilated SMAP data, the r value is enhanced for Africa, Asia, and North America by 0.016, 0.013, and 0.013, respectively (p < 0.05). Significant improvement in r appears in single-cropping agricultural land where the irrigation is not considered in the model but well captured by SMAP (e.g., 0.09 in North America, p < 0.05). With the assimilation of SMAP, areas with weak model performances are identified in double or triple cropping cropland (e.g., part of North China Plain) and/or mountainous area (e.g., Spain and Turkey). The correlation coefficient is enhanced by 0.01 in global average for shrub, grass, and cropland. This enhancement is small and insignificant because nonwater-stressed areas are included.

Determination of structure parameters in strong-field tunneling ionization theory of molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao Songfeng; Jin Cheng; College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070

2010-03-15

In the strong field molecular tunneling ionization theory of Tong et al. [Phys. Rev. A 66, 033402 (2002)], the ionization rate depends on the asymptotic wave function of the molecular orbital from which the electron is removed. The orbital wave functions obtained from standard quantum chemistry packages in general are not good enough in the asymptotic region. Here we construct a one-electron model potential for several linear molecules using density functional theory. We show that the asymptotic wave function can be improved with an iteration method and after one iteration accurate asymptotic wave functions and structure parameters are determined. Withmore » the new parameters we examine the alignment-dependent tunneling ionization probabilities for several molecules and compare with other calculations and with recent measurements, including ionization from inner molecular orbitals.« less

Comparison of recall and daily self-report of fecal incontinence severity.

PubMed

Fisher, Katharine; Bliss, Donna Z; Savik, Kay

2008-01-01

Fecal incontinence (FI) severity is determined by self-report, and most tools rely on recall of symptoms. This study examined whether recall of FI severity differed from daily reports on a diary and the factors influencing any difference. INSTRUMENTS AND DESIGN: Data of 96 participants (mean age 59 years, 78% female) reported on 3 data collection forms (a demographics form, a bowel history, and a stool diary) were analyzed. Data collected during an initial bowel history when participants reported FI severity using recall were compared to similar data participants recorded on a 14-day daily stool diary during a baseline period of a study investigating the effects of different types of dietary fiber on FI. The total FI severity score from the daily stool diary (median 5.0, range 1.2-15.5; P = .04) was significantly higher (worse FI) than the recalled bowel history (median 3.0, range 0.36-27.5). A higher, more positive difference in scores between recall and daily diary reporting indicated greater underreporting on recall. Caregivers underreported FI severity on recall compared to noncaregivers (P = .003). Reasons for underreporting FI are probably multifactorial; findings suggest that being a caregiver and having double incontinence are contributing factors. Clinicians should inquire about FI with a discerning yet sensitive approach. Use of a daily stool diary is recommended in research and may be useful in practice.

Aminopyridinate-FI hybrids, their hafnium and titanium complexes, and their application in the living polymerization of 1-hexene.

PubMed

Haas, Isabelle; Dietel, Thomas; Press, Konstantin; Kol, Moshe; Kempe, Rhett

2013-10-11

Based on two well-established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap-FI hybrid ligands were developed. Four different Ap-FI hybrid ligands were synthesized through a simple condensation reaction and fully characterized. The reaction of hafnium tetrabenzyl with all four Ap-FI hybrid ligands exclusively led to mono(Ap-FI) complexes of the type [(Ap-FI)HfBn2 ]. The ligands acted as tetradentate dianionic chelates. Upon activation with tris(pentafluorophenyl)borane, the hafnium-dibenzyl complexes led to highly active catalysts for the polymerization of 1-hexene. Ultrahigh molecular weights and extremely narrow polydispersities support the living nature of this polymerization process. A possible deactivation product of the hafnium catalysts was characterized by single-crystal X-ray analysis and is discussed. The coordination modes of these new ligands were studied with the help of model titanium complexes. The reaction of titanium(IV) isopropoxide with ligand 1 led to a mono(Ap-FI) complex, which showed the desired fac-mer coordination mode. Titanium (IV) isopropoxide reacted with ligand 4 to give a complex of the type [(ApH-FI)2 Ti(OiPr)2 ], which featured the ligand in its monoanionic form. The two titanium complexes were characterized by X-ray crystal-structure analysis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Assessment of Fixed Interval Timing in Free-Flying Honey Bees (Apis mellifera ligustica): An Analysis of Individual Performance

PubMed Central

Craig, David Philip Arthur; Varnon, Christopher A.; Sokolowski, Michel B. C.; Wells, Harrington; Abramson, Charles I.

2014-01-01

Interval timing is a key element of foraging theory, models of predator avoidance, and competitive interactions. Although interval timing is well documented in vertebrate species, it is virtually unstudied in invertebrates. In the present experiment, we used free-flying honey bees (Apis mellifera ligustica) as a model for timing behaviors. Subjects were trained to enter a hole in an automated artificial flower to receive a nectar reinforcer (i.e. reward). Responses were continuously reinforced prior to exposure to either a fixed interval (FI) 15-sec, FI 30-sec, FI 60-sec, or FI 120-sec reinforcement schedule. We measured response rate and post-reinforcement pause within each fixed interval trial between reinforcers. Honey bees responded at higher frequencies earlier in the fixed interval suggesting subject responding did not come under traditional forms of temporal control. Response rates were lower during FI conditions compared to performance on continuous reinforcement schedules, and responding was more resistant to extinction when previously reinforced on FI schedules. However, no “scalloped” or “break-and-run” patterns of group or individual responses reinforced on FI schedules were observed; no traditional evidence of temporal control was found. Finally, longer FI schedules eventually caused all subjects to cease returning to the operant chamber indicating subjects did not tolerate the longer FI schedules. PMID:24983960

Radiofrequency radiation emitted from Wi-Fi (2.4 GHz) causes impaired insulin secretion and increased oxidative stress in rat pancreatic islets.

PubMed

Masoumi, Ali; Karbalaei, Narges; Mortazavi, S M J; Shabani, Mohammad

2018-06-18

There is a great concern regarding the possible adverse effects of electromagnetic radiation (EMR). This study investigated the effects of EMR induced by Wi-Fi (2.45GHz) on insulin secretion and antioxidant redox systems in the rat pancreas. Adult male Sprague-Dawley rats in the weight range of 230 to 260 g were divided into control, sham, Wi-Fi exposed groups. After long term exposure (4 h/day for 45 days) to Wi-Fi electromagnetic radiation, plasma levels of glucose and insulin during intraperitoneal glucose tolerance test were measured. Islet insulin secretion and content, lipid peroxidation and antioxidant status in pancreas of rats were determined. Our data showed that the weight gain in the WI-FI exposed group was significantly lower than the control group (p<0.05). Wi-Fi (2.45 GHz) exposed group showed hyperglycemia. Plasma insulin level and glucose-stimulated insulin secretion from pancreatic islet were significantly reduced in the Wi-Fi exposed group. EMR emitted from Wi-Fi caused a significant increase in lipid peroxidation and a significant decrease in GSH level, SOD and GPx activities of the pancreas. these data showed that EMR of Wi-Fi leads to hyperglycemia, increased oxidative stress and impaired insulin secretion in the rat pancreatic islets.

Food security status among grade 5 students in Nova Scotia, Canada and its association with health outcomes.

PubMed

Kirk, Sara F L; Kuhle, Stefan; McIsaac, Jessie-Lee D; Williams, Patty L; Rossiter, Melissa; Ohinmaa, Arto; Veugelers, Paul J

2015-11-01

Food security (FS) exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their needs. The present research sought to determine whether students from households experiencing moderate or severe food insecurity (FI) had poorer diet quality, higher body weights and poorer psychosocial outcomes than students from households classed as having high FS or marginal FI status. Population-based survey conducted in schools. Multiple regression analysis was used to explore associations between FS status (high FS; marginal, moderate, severe FI), dietary behaviours and intake, and health-related outcomes (body weight, quality of life, mood, peer relationships, externalizing problems). Nova Scotia, Canada. Grade 5 students (n 5853), aged 10-11 years, with complete information on FS status and student outcomes. In this sample, rates of household FS were 73·5% (high FS), 8·3% (marginal FI) 10·2% (moderate FI) and 7·1% (severe FI status). Students living in households experiencing moderate or severe FI had poorer diet quality, higher BMI and poorer psychosocial outcomes than students classed as having high FS or marginal FI. These findings provide important evidence for policy makers on the prevalence of FI among families in Nova Scotia with grade 5 children and its relationship with childhood nutrition, psychosocial and quality of life factors, and weight status.

Quantum state-resolved probing of strong-field-ionized xenon atoms using femtosecond high-order harmonic transient absorption spectroscopy.

PubMed

Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E; Santra, Robin; Buth, Christian; Leone, Stephen R

2007-04-06

Femtosecond high-order harmonic transient absorption spectroscopy is used to resolve the complete |j,m quantum state distribution of Xe+ produced by optical strong-field ionization of Xe atoms at 800 nm. Probing at the Xe N4/5 edge yields a population distribution rhoj,|m| of rho3/2,1/2ratiorho1/2,1/2ratiorho3/2,3/2=75+/-6 :12+/-3 :13+/-6%. The result is compared to a tunnel ionization calculation with the inclusion of spin-orbit coupling, revealing nonadiabatic ionization behavior. The sub-50-fs time resolution paves the way for tabletop extreme ultraviolet absorption probing of ultrafast dynamics.

Changing fire regimes and the avifauna of California oak woodlands

Treesearch

Kathryn L. Purcell; Scott L. Stephens

2005-01-01

Abstract. Natural and anthropogenic fi re once played an important role in oak woodlands of California. Although lightning-ignited fi res were infrequent, the California Indians used fi re to modify oak woodland vegetation for at least 3,000 yr. These high-frequency, low-intensity fi res likely resulted in little mortality of mature oaks, low but continuous tree...

Influence of ionization on ultrafast gas-based nonlinear fiber optics.

PubMed

Chang, W; Nazarkin, A; Travers, J C; Nold, J; Hölzer, P; Joly, N Y; Russell, P St J

2011-10-10

We numerically investigate the effect of ionization on ultrashort high-energy pulses propagating in gas-filled kagomé-lattice hollow-core photonic crystal fibers by solving an established uni-directional field equation. We consider the dynamics of two distinct regimes: ionization induced blue-shift and resonant dispersive wave emission in the deep-UV. We illustrate how the system evolves between these regimes and the changing influence of ionization. Finally, we consider the effect of higher ionization stages.

Characterization of Pelvic Floor Symptoms in Women of Northeastern Liberia

PubMed Central

Bowling, C. Bryce; Munoz, Oxana; Gerten, Kimberly A.; Mann, MerryLynn; Taryor, Rebecca; Norman, Andy M.; Szychowski, Jeff M.; Richter, Holly E.

2013-01-01

Objective To characterize prevalence and quality of life (QoL) impact of urinary incontinence (UI), fecal incontinence (FI), and pelvic organ prolapse (POP) symptoms in women of Liberia. Methods A questionnaire addressing symptoms and QoL impact of UI, FI and POP was administered to women in a community setting in Ganta, Liberia. Questionnaires were analyzed to determine prevalence rates, QoL impact, and risk factors for these conditions. Results 424 participants were surveyed; 1.7% reported UI, 0.10% reported any form of FI, and 3.3% reported some degree of POP symptoms. QoL responses varied among symptom groups. Previous hysterectomy, cesarean delivery, vaginal deliveries, and body mass index had no significant association with UI, FI, or POP. Participants with UI symptoms were more likely to report FI symptoms (p=0.002). Conclusion Prevalence rates for UI, FI and POP in this population are low; there was a significant association of FI symptoms in subjects with UI. PMID:20206351

Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks

PubMed Central

Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

2016-01-01

To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning. PMID:27608019

Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks.

PubMed

Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

2016-09-05

To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning.

Reduced oxygen concentration for the resuscitation of infants with congenital diaphragmatic hernia.

PubMed

Riley, John S; Antiel, Ryan M; Rintoul, Natalie E; Ades, Anne M; Waqar, Lindsay N; Lin, Nan; Herkert, Lisa M; D'Agostino, Jo Ann; Hoffman, Casey; Peranteau, William H; Flake, Alan W; Adzick, N Scott; Hedrick, Holly L

2018-06-11

To evaluate whether infants with congenital diaphragmatic hernia (CDH) can be safely resuscitated with a reduced starting fraction of inspired oxygen (FiO 2 ) of 0.5. A retrospective cohort study comparing 68 patients resuscitated with starting FiO 2 0.5 to 45 historical controls resuscitated with starting FiO 2 1.0. Reduced starting FiO 2 had no adverse effect upon survival, duration of intubation, need for ECMO, duration of ECMO, or time to surgery. Furthermore, it produced no increase in complications, adverse neurological events, or neurodevelopmental delay. The need to subsequently increase FiO 2 to 1.0 was associated with female sex, lower gestational age, liver up, lower lung volume-head circumference ratio, decreased survival, a higher incidence of ECMO, longer time to surgery, periventricular leukomalacia, and lower neurodevelopmental motor scores. Starting FiO 2 0.5 may be safe for the resuscitation of CDH infants. The need to increase FiO 2 to 1.0 during resuscitation is associated with worse outcomes.

Wi-Fi/MARG Integration for Indoor Pedestrian Localization.

PubMed

Tian, Zengshan; Jin, Yue; Zhou, Mu; Wu, Zipeng; Li, Ze

2016-12-10

With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG) sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR) and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF) based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely.

Tracking Human Mobility Using WiFi Signals.

PubMed

Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

2015-01-01

We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking.

A highly sensitive electron spectrometer for crossed-beam collisional ionization: A retarding-type magnetic bottle analyzer and its application to collision-energy resolved Penning ionization electron spectroscopy

NASA Astrophysics Data System (ADS)

Yamakita, Yoshihiro; Tanaka, Hideyasu; Maruyama, Ryo; Yamakado, Hideo; Misaizu, Fuminori; Ohno, Koichi

2000-08-01

A highly sensitive electron energy analyzer which utilizes a "magnetic bottle" combined with a retarding electrostatic field has been developed for Penning ionization electron spectroscopy. A beam of metastable rare-gas atoms is crossed with a continuous supersonic sample beam in the source region of the analyzer. The emitted electrons are collected by an inhomogeneous magnetic field (the magnetic bottle effect) with a high efficiency of nearly 4π solid angle, which is more than 103 times higher than that of a conventional hemispherical analyzer. The kinetic energy of electrons is analyzed by scanning the retarding field in a flight tube of the analyzer in the presence of a weak magnetic field. The velocity of the metastable atoms can also be resolved by a time-of-flight method in the present instrument. Examples of Penning ionization electron energy spectra as a function of collision energy are presented for Ar and N2 with metastable He*(2 3S) atoms. This instrument has opened the possibility for extensive studies of Penning ionization electron spectroscopy for low-density species, such as clusters, ions, electronically excited species, unstable or transient species, and large molecules with low volatility.

Wi-Fi technology--an uncontrolled global experiment on the health of mankind.

PubMed

Markov, Marko; Grigoriev, Yuri G

2013-06-01

The twenty-first century is marked with exponentially increasing development of technologies that provide wireless communications. To the pollution of the atmosphere with radio and TV signals, not only satellite communications but also any varieties of the Wi-Fi networks are added. By 2010 in the USA, 285 million mobile phone subscribers have been registered (for a little bit more than 300 million inhabitants). The estimate for the world is more than 5 billion mobile phone users at approximately 7 billion people living on this planet. Approximately 2 years ago, the International Agency of Research on Cancer (IARC) classified the electromagnetic fields used in mobile communication as a possible cancerogene. This paper discusses the potential health hazard and lack of scientific assessment and regulatory actions in protection of the life on the planet.

Laser-based methods for the analysis of low molecular weight compounds in biological matrices.

PubMed

Kiss, András; Hopfgartner, Gérard

2016-07-15

Laser-based desorption and/or ionization methods play an important role in the field of the analysis of low molecular-weight compounds (LMWCs) because they allow direct analysis with high-throughput capabilities. In the recent years there were several new improvements in ionization methods with the emergence of novel atmospheric ion sources such as laser ablation electrospray ionization or laser diode thermal desorption and atmospheric pressure chemical ionization and in sample preparation methods with the development of new matrix compounds for matrix-assisted laser desorption/ionization (MALDI). Also, the combination of ion mobility separation with laser-based ionization methods starts to gain popularity with access to commercial systems. These developments have been driven mainly by the emergence of new application fields such as MS imaging and non-chromatographic analytical approaches for quantification. This review aims to present these new developments in laser-based methods for the analysis of low-molecular weight compounds by MS and several potential applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Miniature Free-Space Electrostatic Ion Thrusters

NASA Technical Reports Server (NTRS)

Hartley, Frank T.; Stephens, James B.

2006-01-01

A miniature electrostatic ion thruster is proposed for maneuvering small spacecraft. In a thruster based on this concept, one or more propellant gases would be introduced into an ionizer based on the same principles as those of the device described in an earlier article, "Miniature Bipolar Electrostatic Ion Thruster". On the front side, positive ions leaving an ionizer element would be accelerated to high momentum by an electric field between the ionizer and an accelerator grid around the periphery of the concave laminate structure. On the front side, electrons leaving an ionizer element would be ejected into free space by a smaller accelerating field. The equality of the ion and electron currents would eliminate the need for an additional electron- or ion-emitting device to keep the spacecraft charge-neutral. In a thruster design consisting of multiple membrane ionizers in a thin laminate structure with a peripheral accelerator grid, the direction of thrust could then be controlled (without need for moving parts in the thruster) by regulating the supply of gas to specific ionizer.

Two-color ionization injection using a plasma beatwave accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, C. B.; Benedetti, C.; Esarey, E.

Two-color laser ionization injection is a method to generate ultra-low emittance (sub-100 nm transverse normalized emittance) beams in a laser-driven plasma accelerator. A plasma beatwave accelerator is proposed to drive the plasma wave for ionization injection, where the beating of the lasers effectively produces a train of long-wavelength pulses. The plasma beatwave accelerator excites a large amplitude plasma wave with low peak laser electric fields, leaving atomically-bound electrons with low ionization potential. A short-wavelength, low-amplitude ionization injection laser pulse (with a small ponderomotive force and large peak electric field) is used to ionize the remaining bound electrons at a wakemore » phase suitable for trapping, generating an ultra-low emittance electron beam that is accelerated in the plasma wave. Using a plasma beatwave accelerator for wakefield excitation, compared to short-pulse wakefield excitation, allows for a lower amplitude injection laser pulse and, hence, a lower emittance beam may be generated.« less

Two-color ionization injection using a plasma beatwave accelerator

DOE PAGES

Schroeder, C. B.; Benedetti, C.; Esarey, E.; ...

2018-01-10

Two-color laser ionization injection is a method to generate ultra-low emittance (sub-100 nm transverse normalized emittance) beams in a laser-driven plasma accelerator. A plasma beatwave accelerator is proposed to drive the plasma wave for ionization injection, where the beating of the lasers effectively produces a train of long-wavelength pulses. The plasma beatwave accelerator excites a large amplitude plasma wave with low peak laser electric fields, leaving atomically-bound electrons with low ionization potential. A short-wavelength, low-amplitude ionization injection laser pulse (with a small ponderomotive force and large peak electric field) is used to ionize the remaining bound electrons at a wakemore » phase suitable for trapping, generating an ultra-low emittance electron beam that is accelerated in the plasma wave. Using a plasma beatwave accelerator for wakefield excitation, compared to short-pulse wakefield excitation, allows for a lower amplitude injection laser pulse and, hence, a lower emittance beam may be generated.« less

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

DOE PAGES

Weber, T. E.; Intrator, T. P.; Smith, R. J.

2015-04-29

We show through injection of plasma via an annular array of coaxial plasma guns, during the pre-ionization phase of field-reversed configuration (FRC) formation how to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. Our approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ~350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densitiesmore » and higher temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.« less

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, T. E., E-mail: tweber@lanl.gov; Intrator, T. P.; Smith, R. J.

2015-04-15

Injection of plasma via an annular array of coaxial plasma guns during the pre-ionization phase of field-reversed configuration (FRC) formation is shown to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. This approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ∼350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densities and highermore » temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.« less

Tunneling ionization and harmonic generation in two-color fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondo, K.; Kobayashi, Y.; Sagisaka, A.

1996-02-01

Tunneling ionization and harmonic generation in two-color fields were studied with a fundamental beam ({omega}) and its harmonics (2{omega},3{omega}), which were generated by a 100-fs Ti:sapphire laser. Ion yields of atoms and molecules were successfully controlled by means of a change in the relative phase between {omega} and 3{omega} pulses. Two-color interference was clearly observed in photoelectron spectra and harmonic spectra. In the {omega}{endash}2{omega} field even-order harmonics were observed in which the intensity was almost equal to that of the odd harmonics because of an asymmetric optical field. These results were compared with the quasi-static model for ionization and withmore » the quantum theory for harmonic generation. {copyright} {ital 1996 Optical Society of America.}« less

7TH International Symposium: Nanostructure: Physics and Technology

DTIC Science & Technology

1999-01-01

within the density functional theory [8]. The Hamiltonian (fit and/H 4 for spin 4" and spin 4. electrons, respectively) is given by: fi) - i2--V[ + E,(r...population of higher energy levels by electrons with spin -1/2. This results in increased polarization of luminescence which may exceed 50% (see curve 1 in...that higher energy lines quench at high field. In addition a change in the linewidth of the emission is found for high electric fields. Introduction

Single Event Test Methodologies and System Error Rate Analysis for Triple Modular Redundant Field Programmable Gate Arrays

NASA Technical Reports Server (NTRS)

Allen, Gregory; Edmonds, Larry D.; Swift, Gary; Carmichael, Carl; Tseng, Chen Wei; Heldt, Kevin; Anderson, Scott Arlo; Coe, Michael

2010-01-01

We present a test methodology for estimating system error rates of Field Programmable Gate Arrays (FPGAs) mitigated with Triple Modular Redundancy (TMR). The test methodology is founded in a mathematical model, which is also presented. Accelerator data from 90 nm Xilins Military/Aerospace grade FPGA are shown to fit the model. Fault injection (FI) results are discussed and related to the test data. Design implementation and the corresponding impact of multiple bit upset (MBU) are also discussed.

Labor Resource Audit and Analysis: A Tool for Management Planning and Control

DTIC Science & Technology

1989-06-01

RM(onn17 COSA~ CODES B 5OBJECT TERMS (Continge pn rev@rj !~cea and f, entfa y.block R V FIELD GROUP SUB-GROUP re-; P anning; labor; ugLr og; a e...David 1 hplr., chairman Department of Admi srtv Sine KnealeT-Mg;fi Dea ofInformation and-ln sine ii ABSTRACT This study was conducted in an effort to...Audit ---------------------------------- 84 viii ACKNOWLEDGMENTS A wide variety of authorities in their field have contributed material to this study. I

Gas dispersal potential of bedding as a cause for sudden infant death.

PubMed

Sakai, Jun; Kanetake, Jun; Takahashi, Shirushi; Kanawaku, Yoshimasa; Funayama, Masato

2008-09-18

We assessed the gas dispersal potential of bedding articles used by 14 infants diagnosed with sudden unexpected infant death at autopsy. Of these cases, eight exhibited FiCO(2) values greater than 10% within 2.5 min, six of which were found prone and two supine. The results demonstrated that these eight beddings had a high rebreathing potential if they covered the babies' faces. We did not, however, take into account in our model the large tissue stores of CO(2). As some bicarbonate pools will delay or suppress the increase of FiCO(2), the time-FiCO(2) graphs of this study are not true for living infants. This model, however, demonstrated the potential gas dispersal ability of bedding. The higher the FiCO(2) values, the more dangerous the situation for rebreathing infants. In addition, FiO(2) in the potential space around the model's face can be estimated mathematically using FiCO(2) values. The FiO(2) graph pattern for each bedding item corresponded roughly to the inverse of the FiCO(2) time course. The FiO(2) of the above eight cases decreased by 8.5% within 2.5 min. Recent studies using living infants placed prone to sleep reported that some babies exhibited larger decreases in FiO(2) than increases observed in FiCO(2). While the decrease of FiO(2) in our model is still theoretical, CO(2) accumulation and O(2) deprivation are closely related. If a striking O(2) deficiency occurs in a short period, babies can lose consciousness before an arousal response is evoked and all infants could be influenced by the poor gas dispersal of bedding; the main cause of sudden death in infancy would thus be asphyxia. When the bedding is soft, the potential for trapping CO(2) seems to be high; however, it is impossible to assess it by appearance alone. We sought to provide some objective indices for the assessment of respiratory compromise in relation to bedding using our model. When a baby is found unresponsive with his/her face covered with poor gas dispersal bedding, we should consider the possibility of asphyxia.

A universal definition of ARDS: the PaO2/FiO2 ratio under a standard ventilatory setting--a prospective, multicenter validation study.

PubMed

Villar, Jesús; Pérez-Méndez, Lina; Blanco, Jesús; Añón, José Manuel; Blanch, Lluís; Belda, Javier; Santos-Bouza, Antonio; Fernández, Rosa Lidia; Kacmarek, Robert M

2013-04-01

The PaO2/FiO2 is an integral part of the assessment of patients with acute respiratory distress syndrome (ARDS). The American-European Consensus Conference definition does not mandate any standardization procedure. We hypothesized that the use of PaO2/FiO2 calculated under a standard ventilatory setting within 24 h of ARDS diagnosis allows a more clinically relevant ARDS classification. We studied 452 ARDS patients enrolled prospectively in two independent, multicenter cohorts treated with protective mechanical ventilation. At the time of ARDS diagnosis, patients had a PaO2/FiO2 ≤ 200. In the derivation cohort (n = 170), we measured PaO2/FiO2 with two levels of positive end-expiratory pressure (PEEP) (≥ 5 and ≥ 10 cmH2O) and two levels of FiO2 (≥ 0.5 and 1.0) at ARDS onset and 24 h later. Dependent upon PaO2 response, patients were reclassified into three groups: mild (PaO2/FiO2 > 200), moderate (PaO2/FiO2 101-200), and severe (PaO2/FiO2 ≤ 100) ARDS. The primary outcome measure was ICU mortality. The standard ventilatory setting that reached the highest significance difference in mortality among these categories was tested in a separate cohort (n = 282). The only standard ventilatory setting that identified the three PaO2/FiO2 risk categories in the derivation cohort was PEEP ≥ 10 cmH2O and FiO2 ≥ 0.5 at 24 h after ARDS onset (p = 0.0001). Using this ventilatory setting, patients in the validation cohort were reclassified as having mild ARDS (n = 47, mortality 17 %), moderate ARDS (n = 149, mortality 40.9 %), and severe ARDS (n = 86, mortality 58.1 %) (p = 0.00001). Our method for assessing PaO2/FiO2 greatly improved risk stratification of ARDS and could be used for enrolling appropriate ARDS patients into therapeutic clinical trials.

Worlds apart? A scoping review addressing different stakeholder perspectives on barriers to family involvement in the care for persons with severe mental illness.

PubMed

Landeweer, Elleke; Molewijk, Bert; Hem, Marit Helene; Pedersen, Reidar

2017-05-15

Empirical evidence shows that family involvement (FI) can play a pivotal role in the coping and recovery of persons with severe mental illness (SMI). Nevertheless, various studies demonstrate that FI in mental healthcare services is often not (sufficiently) realized. In order to develop more insights, this scoping review gives an overview of how various stakeholders conceptualize, perceive and experience barriers to FI. Central questions are: 1) What are the main barriers to FI reported by the different key stakeholders (i.e. the persons with SMI, their families and the professionals, and 2) What are the differences and similarities between the various stakeholders' perspectives on these barriers. A systematic search into primary studies regarding FI was conducted in four databases: Medline/Pubmed, Cinahl, PsychInfo and Web of Knowledge with the use of a PICO scheme. Thematic analysis focused on stakeholder perspectives (i.e. which stakeholder group reports the barrier) and types of barriers (i.e. which types of barriers are addressed). Thirty three studies were included. The main barriers reported by the stakeholder groups reveal important similarities and differences between the stakeholder groups and were related to: 1) the person with SMI, 2) the family, 3) the professionals, 4) the organization of care and 5) the culture-paradigm. Our stakeholder approach elicits the different stakeholders' concepts, presuppositions and experiences of barriers to FI, and gives fundamental insights on how to deal with barriers to FI. The stakeholders differing interpretations and perceptions of the barriers related to FI is closely related to the inherent complexity involved in FI in itself. In order to deal better with these barriers, openly discussing and reflecting upon each other's normative understandings of barriers is needed. Differences in perceptions of barriers to FI can itself be a barrier. To deal with barriers to FI, a dialogical approach on how the different stakeholders perceive and value FI and its barriers is required. Methods such as moral case deliberation or systematic ethics reflections can be useful.

Robin Hood Effects on Motivation in Math: Family Interest Moderates the Effects of Relevance Interventions

ERIC Educational Resources Information Center

Häfner, Isabelle; Flunger, Barbara; Dicke, Anna-Lena; Gaspard, Hanna; Brisson, Brigitte M.; Nagengast, Benjamin; Trautwein, Ulrich

2017-01-01

Using a cluster randomized field trial, the present study tested whether 2 relevance interventions affected students' value beliefs, self-concept, and effort in math differently depending on family background (socioeconomic status, family interest (FI), and parental utility value). Eighty-two classrooms were randomly assigned to either 1 of 2…

Longitudinal measurements of tarnished plant bug (Hemiptera: Miridae) susceptibility to insecticides in Arkansas, Louisiana and Mississippi: Associations with insecticide use and insect control recommendations

USDA-ARS?s Scientific Manuscript database

Dose-response assays were conducted from 2008 through 2015 to measure the susceptibility of field populations of Lygus lineolaris (Palisot de Beauvois) from the Delta regions of Arkansas, Louisiana and Mississippi to acephate, imidacloprid, thiamethoxam, permethrin and sulfoxaflor. A total of 229 fi...

USV Path Planning Using Potential Field Model

DTIC Science & Technology

2017-09-01

control system and hardware used. Figure 24. Control System Block Diagram The course commands are passed via Wi - Fi to the USV where the low...plane about the center. The estimated moment of inertia is 2 2 2 2 2( ) 36(1.35 0.98 ) 8.35 12 12 m b wI kg m+ += = = • . (41) b. Added

Comparison between Frailty Index of Deficit Accumulation and Phenotypic Model to Predict Risk of Falls: Data from the Global Longitudinal Study of Osteoporosis in Women (GLOW) Hamilton Cohort

PubMed Central

Thabane, Lehana; Ioannidis, George; Kennedy, Courtney; Papaioannou, Alexandra

2015-01-01

Objectives To compare the predictive accuracy of the frailty index (FI) of deficit accumulation and the phenotypic frailty (PF) model in predicting risks of future falls, fractures and death in women aged ≥55 years. Methods Based on the data from the Global Longitudinal Study of Osteoporosis in Women (GLOW) 3-year Hamilton cohort (n = 3,985), we compared the predictive accuracy of the FI and PF in risks of falls, fractures and death using three strategies: (1) investigated the relationship with adverse health outcomes by increasing per one-fifth (i.e., 20%) of the FI and PF; (2) trichotomized the FI based on the overlap in the density distribution of the FI by the three groups (robust, pre-frail and frail) which were defined by the PF; (3) categorized the women according to a predicted probability function of falls during the third year of follow-up predicted by the FI. Logistic regression models were used for falls and death, while survival analyses were conducted for fractures. Results The FI and PF agreed with each other at a good level of consensus (correlation coefficients ≥ 0.56) in all the three strategies. Both the FI and PF approaches predicted adverse health outcomes significantly. The FI quantified the risks of future falls, fractures and death more precisely than the PF. Both the FI and PF discriminated risks of adverse outcomes in multivariable models with acceptable and comparable area under the curve (AUCs) for falls (AUCs ≥ 0.68) and death (AUCs ≥ 0.79), and c-indices for fractures (c-indices ≥ 0.69) respectively. Conclusions The FI is comparable with the PF in predicting risks of adverse health outcomes. These findings may indicate the flexibility in the choice of frailty model for the elderly in the population-based settings. PMID:25764521

Injection Drug Use, Unemployment, and Severe Food Insecurity Among HIV-HCV Co-Infected Individuals: A Mediation Analysis.

PubMed

McLinden, Taylor; Moodie, Erica E M; Hamelin, Anne-Marie; Harper, Sam; Walmsley, Sharon L; Paradis, Gilles; Aibibula, Wusiman; Klein, Marina B; Cox, Joseph

2017-12-01

Severe food insecurity (FI), which indicates reduced food intake, is common among HIV-hepatitis C virus (HCV) co-infected individuals. Given the importance of unemployment as a proximal risk factor for FI, this mediation analysis examines a potential mechanism through which injection drug use (IDU) is associated with severe FI. We used biannual data from the Canadian Co-infection Cohort (N = 429 with 3 study visits, 2012-2015). IDU in the past 6 months (exposure) and current unemployment (mediator) were self-reported. Severe FI in the following 6 months (outcome) was measured using the Household Food Security Survey Module. An overall association and a controlled direct effect were estimated using marginal structural models. Among participants, 32% engaged in IDU, 78% were unemployed, and 29% experienced severe FI. After adjustment for confounding and addressing censoring through weighting, the overall association (through all potential pathways) between IDU and severe FI was: risk ratio (RR) = 1.69 (95% confidence interval [CI] = 1.15-2.48). The controlled direct effect (the association through all potential pathways except that of unemployment) was: RR = 1.65 (95% CI = 1.08-2.53). We found evidence of an overall association between IDU and severe FI and estimated a controlled direct effect that is suggestive of pathways from IDU to severe FI that are not mediated by unemployment. Specifically, an overall association and a controlled direct effect that are similar in magnitude suggests that the potential impact of IDU on unemployment is not the primary mechanism through which IDU is associated with severe FI. Therefore, while further research is required to understand the mechanisms linking IDU and severe FI, the strong overall association suggests that reductions in IDU may mitigate severe FI in this vulnerable subset of the HIV-positive population.

Comparison between frailty index of deficit accumulation and phenotypic model to predict risk of falls: data from the global longitudinal study of osteoporosis in women (GLOW) Hamilton cohort.

PubMed

Li, Guowei; Thabane, Lehana; Ioannidis, George; Kennedy, Courtney; Papaioannou, Alexandra; Adachi, Jonathan D

2015-01-01

To compare the predictive accuracy of the frailty index (FI) of deficit accumulation and the phenotypic frailty (PF) model in predicting risks of future falls, fractures and death in women aged ≥55 years. Based on the data from the Global Longitudinal Study of Osteoporosis in Women (GLOW) 3-year Hamilton cohort (n = 3,985), we compared the predictive accuracy of the FI and PF in risks of falls, fractures and death using three strategies: (1) investigated the relationship with adverse health outcomes by increasing per one-fifth (i.e., 20%) of the FI and PF; (2) trichotomized the FI based on the overlap in the density distribution of the FI by the three groups (robust, pre-frail and frail) which were defined by the PF; (3) categorized the women according to a predicted probability function of falls during the third year of follow-up predicted by the FI. Logistic regression models were used for falls and death, while survival analyses were conducted for fractures. The FI and PF agreed with each other at a good level of consensus (correlation coefficients ≥ 0.56) in all the three strategies. Both the FI and PF approaches predicted adverse health outcomes significantly. The FI quantified the risks of future falls, fractures and death more precisely than the PF. Both the FI and PF discriminated risks of adverse outcomes in multivariable models with acceptable and comparable area under the curve (AUCs) for falls (AUCs ≥ 0.68) and death (AUCs ≥ 0.79), and c-indices for fractures (c-indices ≥ 0.69) respectively. The FI is comparable with the PF in predicting risks of adverse health outcomes. These findings may indicate the flexibility in the choice of frailty model for the elderly in the population-based settings.

Effect of FiO2 in the measurement of VO2 and VCO2 using the E-COXV metabolic monitor.

PubMed

Ferreruela, M; Raurich, J M; Llompart-Pou, J A; Colomar, A; Ayestarán, I

2017-11-01

We evaluated the effect of changes in FiO 2 on the bias and accuracy of the determination of oxygen consumption (V˙O 2 ) and carbon dioxide production (V˙CO 2 ) using the E-COVX monitor in patients with mechanical ventilation. Descriptive of concordance. Intensive Care Unit. Patients with mechanical ventilation. We measured V˙O 2 and V˙CO 2 using the E-COVX monitor. Values recorded were the average in 5min. Two groups of 30 patients. We analyzed: 1) the reproducibility in the measurement of V˙O 2 and V˙CO 2 at FiO 2 0.4, and 2) the effect of the changes in FiO 2 on the measurement of V˙O 2 and V˙CO 2 . Statistical analysis was performed using Bland and Altman test. Bias and accuracy. 1) FiO 2 0.4 reproducibility: The bias in the measurement of V˙O 2 and V˙CO 2 was 1.6 and 2.1mL/min, respectively, and accuracy was 9.7 to -8.3% and 7.2 to -5.2%, respectively, and 2) effect of FiO 2 on V˙O 2 : The bias of V˙O 2 measured at FiO 2 0.4 and 0.6 was -4.0mL/min and FiO 2 0.4 and 0.8 was 5.2mL/min. Accuracy between FiO 2 0.4 and 0.6 was 11.9 to -14.1%, and between FiO 2 0.4 and 0.8 was 43.9 to -39.7%. The E-COVX monitor evaluates V˙O 2 and V˙CO 2 in critical patients with mechanical ventilation with a clinically acceptable accuracy until FiO 2 0.6. Copyright © 2017 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Novel high power impulse magnetron sputtering enhanced by an auxiliary electrical field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chunwei, E-mail: lcwnefu@126.com, E-mail: xiubotian@163.com; State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001; Tian, Xiubo, E-mail: lcwnefu@126.com, E-mail: xiubotian@163.com

2016-08-15

The high power impulse magnetron sputtering (HIPIMS) technique is a novel highly ionized physical vapor deposition method with a high application potential. However, the electron utilization efficiency during sputtering is rather low and the metal particle ionization rate needs to be considerably improved to allow for a large-scale industrial application. Therefore, we enhanced the HIPIMS technique by simultaneously applying an electric field (EF-HIPIMS). The effect of the electric field on the discharge process was studied using a current sensor and an optical emission spectrometer. Furthermore, the spatial distribution of the electric potential and electric field during the EF-HIPIMS process wasmore » simulated using the ANSYS software. The results indicate that a higher electron utilization efficiency and a higher particle ionization rate could be achieved. The auxiliary anode obviously changed the distribution of the electric potential and the electric field in the discharge region, which increased the plasma density and enhanced the degree of ionization of the vanadium and argon gas. Vanadium films were deposited to further compare both techniques, and the morphology of the prepared films was investigated by scanning electron microscopy. The films showed a smaller crystal grain size and a denser growth structure when the electric field was applied during the discharge process.« less

Applicability of post-ionization theory to laser-assisted field evaporation of magnetite

DOE PAGES

Schreiber, Daniel K.; Chiaramonti, Ann N.; Gordon, Lyle M.; ...

2014-12-15

Analysis of the mean Fe ion charge state from laser-assisted field evaporation of magnetite (Fe3O4) reveals unexpected trends as a function of laser pulse energy that break from conventional post-ionization theory for metals. For Fe ions evaporated from magnetite, the effects of post-ionization are partially offset by the increased prevalence of direct evaporation into higher charge states with increasing laser pulse energy. Therefore the final charge state is related to both the field strength and the laser pulse energy, despite those variables themselves being intertwined when analyzing at a constant detection rate. Comparison of data collected at different base temperaturesmore » also show that the increased prevalence of Fe2+ at higher laser energies is possibly not a direct thermal effect. Conversely, the ratio of 16O+:16O2+ is well-correlated with field strength and unaffected by laser pulse energy on its own, making it a better overall indicator of the field evaporation conditions than the mean Fe charge state. Plotting the normalized field strength versus laser pulse energy also elucidates a non-linear dependence, in agreement with previous observations on semiconductors, that suggests a field-dependent laser absorption efficiency. Together these observations demonstrate that the field evaporation process for laser-pulsed oxides exhibits fundamental differences from metallic specimens that cannot be completely explained by post-ionization theory. Further theoretical studies, combined with detailed analytical observations, are required to understand fully the field evaporation process of non-metallic samples.« less

Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields

NASA Astrophysics Data System (ADS)

Kim, Ki-Yong; Glownia, James H.; Taylor, Antoinette J.; Rodriguez, George

2007-04-01

A transient photocurrent model is developed to explain coherent terahertz emission from air irradiated by a symmetry-broken laser field composed of the fundamental and its second harmonic laser pulses. When the total laser field is asymmetric across individual optical cycles, a nonvanishing electron current surge can arise during optical field ionization of air, emitting a terahertz electromagnetic pulse. Terahertz power scalability is also investigated, and with optical pump energy of tens of millijoules per pulse, peak terahertz field strengths in excess of 150 kV/cm are routinely produced.

Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields.

PubMed

Kim, Ki-Yong; Glownia, James H; Taylor, Antoinette J; Rodriguez, George

2007-04-16

A transient photocurrent model is developed to explain coherent terahertz emission from air irradiated by a symmetry-broken laser field composed of the fundamental and its second harmonic laser pulses. When the total laser field is asymmetric across individual optical cycles, a nonvanishing electron current surge can arise during optical field ionization of air, emitting a terahertz electromagnetic pulse. Terahertz power scalability is also investigated, and with optical pump energy of tens of millijoules per pulse, peak terahertz field strengths in excess of 150 kV/cm are routinely produced.

Soft ionization device with characterization systems and methods of manufacture

NASA Technical Reports Server (NTRS)

Hartley, Frank T. (Inventor)

2004-01-01

Various configurations of characterization systems such as ion mobility spectrometers and mass spectrometers are disclosed that are coupled to an ionization device. The ionization device is formed of a membrane that houses electrodes therein that are located closer to one another than the mean free path of the gas being ionized. Small voltages across the electrodes generate large electric fields which act to ionize substantially all molecules passing therethrough without fracture. Methods to manufacture the mass spectrometer and ion mobility spectrometer systems are also described.

Seasonal Progression of the Deposition of Black Carbon by Snowfall at Ny-Ålesund, Spitsbergen

NASA Astrophysics Data System (ADS)

Sinha, P. R.; Kondo, Y.; Goto-Azuma, K.; Tsukagawa, Y.; Fukuda, K.; Koike, M.; Ohata, S.; Moteki, N.; Mori, T.; Oshima, N.; Førland, E. J.; Irwin, M.; Gallet, J.-C.; Pedersen, C. A.

2018-01-01

Deposition of black carbon (BC) aerosol in the Arctic lowers snow albedo, thus contributing to warming in the region. However, the processes and impacts associated with BC deposition are poorly understood because of the scarcity and uncertainties of measurements of BC in snow with adequate spatiotemporal resolution. We sampled snowpack at two sites (11 m and 300 m above sea level) at Ny-Ålesund, Spitsbergen, in April 2013. We also collected falling snow near the surface with a windsock from September 2012 to April 2013. The size distribution of BC in snowpack and falling snow was measured using a single-particle soot photometer combined with a characterized nebulizer. The BC size distributions did not show significant variations with depth in the snowpack, suggesting stable size distributions in falling snow. The BC number and mass concentrations (CNBC and CMBC) at the two sites agreed to within 19% and 10%, respectively, despite the sites' different snow water equivalent (SWE) loadings. This indicates the small influence of the amount of SWE (or precipitation) on these quantities. Average CNBC and CMBC in snowpack and falling snow at nearly the same locations agreed to within 5% and 16%, after small corrections for artifacts associated with the sampling of the falling snow. This comparison shows that the dry deposition was a small contributor to the total BC deposition. CMBC were highest (2.4 ± 3.0 μg L-1) in December-February and lowest (1.2 ± 1.2 μg L-1) in September-November.

Reference data set of volcanic ash physicochemical and optical properties

NASA Astrophysics Data System (ADS)

Vogel, A.; Diplas, S.; Durant, A. J.; Azar, A. S.; Sunding, M. F.; Rose, W. I.; Sytchkova, A.; Bonadonna, C.; Krüger, K.; Stohl, A.

2017-09-01

Uncertainty in the physicochemical and optical properties of volcanic ash particles creates errors in the detection and modeling of volcanic ash clouds and in quantification of their potential impacts. In this study, we provide a data set that describes the physicochemical and optical properties of a representative selection of volcanic ash samples from nine different volcanic eruptions covering a wide range of silica contents (50-80 wt % SiO2). We measured and calculated parameters describing the physical (size distribution, complex shape, and dense-rock equivalent mass density), chemical (bulk and surface composition), and optical (complex refractive index from ultraviolet to near-infrared wavelengths) properties of the volcanic ash and classified the samples according to their SiO2 and total alkali contents into the common igneous rock types basalt to rhyolite. We found that the mass density ranges between ρ = 2.49 and 2.98 g/cm3 for rhyolitic to basaltic ash types and that the particle shape varies with changing particle size (d < 100 μm). The complex refractive indices in the wavelength range between λ = 300 nm and 1500 nm depend systematically on the composition of the samples. The real part values vary from n = 1.38 to 1.66 depending on ash type and wavelength and the imaginary part values from k = 0.00027 to 0.00268. We place our results into the context of existing data and thus provide a comprehensive data set that can be used for future and historic eruptions, when only basic information about the magma type producing the ash is known.

[Patient exposure to electromagnetic fields in magnetic resonance scanners: a review].

PubMed

Guibelalde del Castillo, E

2013-12-01

The use of non-ionizing electromagnetic fields in the low frequency end of the electromagnetic spectrum and static fields, radiofrequencies (RF), and microwaves is fundamental both in modern communication systems and in diagnostic medical imaging techniques like magnetic resonance imaging (MRI). The proliferation of these applications in recent decades has led to intense activity in developing regulations to guarantee their safety and to the establishment of guidelines and legal recommendations for the public, workers, and patients. In April 2012 it was foreseen that the European Parliament and Council would approve and publish a directive on the minimum health and safety requirements regarding the exposure of workers to the risks arising from electromagnetic fields, which would modify Directive 2004/40/EC. New studies related to the exposure to electromagnetic radiation and its impact on health published in recent years have led to a new postponement, and it is now foreseen that the directive will come into effect in October 2013. One of the most noteworthy aspects of the new version of the directive is the exclusion of the limits of occupational exposure to electromagnetic fields in the clinical use of MRI. In exchange for this exception, physicians and experts in protection against non-ionizing radiation are asked to make additional efforts to train workers exposed to non-ionizing radiation and to establish mechanisms to guarantee the correct application of non-ionizing electromagnetic fields in patients, along similar lines to the principles of justification and optimization established for ionizing radiation. On the basis of the most recently published studies, this article reviews some safety-related aspects to take into account when examining patients with MRI with high magnetic fields. Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.

Transit dosimetry in IMRT with an a-Si EPID in direct detection configuration

NASA Astrophysics Data System (ADS)

Sabet, Mahsheed; Rowshanfarzad, Pejman; Vial, Philip; Menk, Frederick W.; Greer, Peter B.

2012-08-01

In this study an amorphous silicon electronic portal imaging device (a-Si EPID) converted to direct detection configuration was investigated as a transit dosimeter for intensity modulated radiation therapy (IMRT). After calibration to dose and correction for a background offset signal, the EPID-measured absolute IMRT transit doses for 29 fields were compared to a MatriXX two-dimensional array of ionization chambers (as reference) using Gamma evaluation (3%, 3 mm). The MatriXX was first evaluated as reference for transit dosimetry. The accuracy of EPID measurements was also investigated by comparison of point dose measurements by an ionization chamber on the central axis with slab and anthropomorphic phantoms in a range of simple to complex fields. The uncertainty in ionization chamber measurements in IMRT fields was also investigated by its displacement from the central axis and comparison with the central axis measurements. Comparison of the absolute doses measured by the EPID and MatriXX with slab phantoms in IMRT fields showed that on average 96.4% and 97.5% of points had a Gamma index<1 in head and neck and prostate fields, respectively. For absolute dose comparisons with anthropomorphic phantoms, the values changed to an average of 93.6%, 93.7% and 94.4% of points with Gamma index<1 in head and neck, brain and prostate fields, respectively. Point doses measured by the EPID and ionization chamber were within 3% difference for all conditions. The deviations introduced in the response of the ionization chamber in IMRT fields were<1%. The direct EPID performance for transit dosimetry showed that it has the potential to perform accurate, efficient and comprehensive in vivo dosimetry for IMRT.

TH-CD-BRA-05: First Water Calorimetric Dw Measurement and Direct Measurement of Magnetic Field Correction Factors, KQ,B, in a 1.5 T B-Field of An MRI Linac

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prez, L de; Pooter, J de; Jansen, B

2016-06-15

Purpose: Reference dosimetry in MR-guided radiotherapy is performed in the presence of a B-field. As a consequence the response of ionization chambers changes considerably and depends on parameters not considered in traditional reference dosimetry. Therefore future Codes of Practices need ionization chamber correction factors to correct for both the change in beam quality and the presence of a B-field. The objective was to study the feasibility of water calorimetric absorbed-dose measurements in a 1.5 T B-field of an MRLinac and the direct measurement of kQ,B calibration of ionization chambers. Methods: Calorimetric absorbed dose to water Dw was measured with amore » new water calorimeter in the bore of an MRLinac (TPR20,10 of 0.702). Two waterproof ionization chambers (PTW 30013, IBA FC-65G) were calibrated inside the calorimeter phantom (ND,w,Q,B). Both measurements were normalized to a monitor ionization chamber. Ionization chamber measurements were corrected for conventional influence parameter. Based on the chambers’ Co-60 calibrations (ND,w,Q0), measured directly against the calorimeter. In this study the correction factors kQ,B was determined as the ratio of the calibration coefficients in the MRLinac and in Co-60. Additionally, kB was determined based on kQ values obtained with the IAEA TRS-398 Code of Practice. Results: The kQ,B factors of the ionization chambers mentioned above were respectively 0.9488(8) and 0.9445(8) with resulting kB factors of 0.961(13) and 0.952(13) with standard uncertainties on the least significant digit(s) between brackets. Conclusion: Calorimetric Dw measurements and calibration of waterproof ionization chambers were successfully carried out in the 1.5 T B-field of an MRLinac with a standard uncertainty of 0.7%. Preliminary kQ,B and kB factors were determined with standard uncertainties of respectively 0.8% and 1.3%. The kQ,B agrees with an alternative method within 0.4%. The feasibility of water calorimetry in the presence of B-fields was demonstrated by the direct determination of Dw and kQ,B. This work was supported by EMRP grant HLT06. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.« less

Processes of ionization of atoms in nonstationary states by the field of an attosecond pulse

NASA Astrophysics Data System (ADS)

Makarov, D. N.; Matveev, V. I.

2015-02-01

Processes of ionization at the interaction of attosecond pulses of an electromagnetic field with atoms in nonstationary states have been considered. The probabilities and ionization cross section at the radiative relaxation of an excited state of a single-electron atom and at the Auger decay of the autoionization state of a two-electron atom have been calculated. The developed method allows the expansion to the case of more complex targets, including those in the collision state, and to various chemical reactions.

Ionization and expansion of barium clouds in the ionosphere

NASA Technical Reports Server (NTRS)

Ma, T.-Z.; Schunk, R. W.

1993-01-01

A recently envelope 3D model is used here to study the motion of the barium clouds released in the ionosphere, including the ionization stage. The ionization and the expansion of the barium clouds and the interaction between the clouds and the background ions are investigated using three simulations: a cloud without a directional velocity, a cloud with an initial velocity of 5 km/s across the B field, and a cloud with initial velocity components of 2 km/s both along and across the B field.

Study of np{sup 2}P{sub 1/2,3/2} Rydberg series of AlI by the method of laser stepwise excitation and ionization by electric field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasimov, A.K.; Tursunov, A.T.; Tukhlibaev, O.

Frequencies of the 4s{sup 2}S{sub 1/2}-np{sup 2}P{sub 1/2, 3/2} transitions are measured and the energies of high-lying P states, as well as the ionization energy of aluminum atoms, are determined by the method of two-step laser excitation and ionization of excited atoms of AlI by an electric field. 4 refs., 3 figs., 1 tab.

Radiofrequency-electromagnetic field exposures in kindergarten children.

PubMed

Bhatt, Chhavi Raj; Redmayne, Mary; Billah, Baki; Abramson, Michael J; Benke, Geza

2017-09-01

The aim of this study was to assess environmental and personal radiofrequency-electromagnetic field (RF-EMF) exposures in kindergarten children. Ten children and 20 kindergartens in Melbourne, Australia participated in personal and environmental exposure measurements, respectively. Order statistics of RF-EMF exposures were computed for 16 frequency bands between 88 MHz and 5.8 GHz. Of the 16 bands, the three highest sources of environmental RF-EMF exposures were: Global System for Mobile Communications (GSM) 900 MHz downlink (82 mV/m); Universal Mobile Telecommunications System (UMTS) 2100MHz downlink (51 mV/m); and GSM 900 MHz uplink (45 mV/m). Similarly, the three highest personal exposure sources were: GSM 900 MHz downlink (50 mV/m); UMTS 2100 MHz downlink, GSM 900 MHz uplink and GSM 1800 MHz downlink (20 mV/m); and Frequency Modulation radio, Wi-Fi 2.4 GHz and Digital Video Broadcasting-Terrestrial (10 mV/m). The median environmental exposures were: 179 mV/m (total all bands), 123 mV/m (total mobile phone base station downlinks), 46 mV/m (total mobile phone base station uplinks), and 16 mV/m (Wi-Fi 2.4 GHz). Similarly, the median personal exposures were: 81 mV/m (total all bands), 62 mV/m (total mobile phone base station downlinks), 21 mV/m (total mobile phone base station uplinks), and 9 mV/m (Wi-Fi 2.4 GHz). The measurements showed that environmental RF-EMF exposure levels exceeded the personal RF-EMF exposure levels at kindergartens.

E-beam ionized channel guiding of an intense relativistic electron beam

DOEpatents

Frost, Charles A.; Godfrey, Brendon B.; Kiekel, Paul D.; Shope, Steven L.

1988-01-01

An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path.

Tracking Human Mobility Using WiFi Signals

PubMed Central

Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

2015-01-01

We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking. PMID:26132115

Impact of Food Insecurity on Depressive Symptoms Among HIV-HCV Co-infected People.

PubMed

Aibibula, Wusiman; Cox, Joseph; Hamelin, Anne-Marie; Moodie, Erica E M; Naimi, Ashley I; McLinden, Taylor; Klein, Marina B; Brassard, Paul

2017-12-01

Food insecurity (FI) is associated with depressive symptoms among HIV mono-infected people. Our objective was to examine to what extent this association holds among HIV-hepatitis C virus (HCV) co-infected people. We used data from a prospective cohort study of HIV-HCV co-infected people in Canada. FI was measured using the ten-item adult scale of Health Canada's Household Food Security Survey Module and was classified into three categories: food secure, moderate FI, and severe FI. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale (CES-D-10) and was classified into absence or presence of depressive symptoms. FI, depressive symptoms, and other covariates were updated every 6 months. The association between FI and depressive symptoms was assessed using a stabilized inverse probability weighted marginal structural model. The study sample included 725 HIV-HCV co-infected people with 1973 person-visits over 3 years of follow up. At baseline, 23% of participants experienced moderate food insecurity, 34% experienced severe food insecurity and 52% had depressive symptoms. People experiencing moderate FI had 1.63 times (95% CI 1.44-1.86) the risk of having depressive symptoms and people experiencing severe FI had 2.01 times (95% CI 1.79-2.25) the risk of having depressive symptoms compared to people who were food secure. FI is a risk factor for developing depressive symptoms among HIV-HCV co-infected people. Food supplementation, psychosocial support and counseling may improve patient health outcomes.

Smooth-pursuit eye movements without head movement disrupt the static body balance.

PubMed

Kim, Sang-Yeob; Moon, Byeong-Yeon; Cho, Hyun Gug

2016-04-01

[Purpose] To investigate the changes of body balance in static posture in smooth-pursuit eye movements (SPEMs) without head movement. [Subjects and Methods] Forty subjects (24 males, 16 females) aged 23.24 ± 2.58 years participated. SPEMs were activated in three directions (horizontal, vertical, and diagonal movements); the target speed was set at three conditions (10°/s, 20°/s, and 30°/s); and the binocular visual field was limited to 50°. To compare the body balance changes, the general stability (ST) and the fall risk index (FI) were measured with TETRAX. The subjects wore a head-neck collar and stood on a balance plate for 32 s during each measurement in three directions. SPEMs were induced to each subject with nine target speeds and directions. All measured values were compared with those in stationary fixation. [Results] The ST and FI increased significantly in all SPEMs directions, with an increased target speed than that in stationary fixation. In the same condition of the target speed, the FI had the highest value relative to diagonal SPEMs. [Conclusion] SPEMs without head movement disrupt the stability of body balance in a static posture, and diagonal SPEMs may have a more negative effect in maintaining body balance than horizontal or vertical SPEMs.

Interval timing under a behavioral microscope: Dissociating motivational and timing processes in fixed-interval performance.

PubMed

Daniels, Carter W; Sanabria, Federico

2017-03-01

The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30 s and FI 90 s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies is sensitive to the periodicity of reinforcement, and prefeeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Prefeeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, latency and IRT models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI schedules fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance. These processes may be obscured, however, when performance in timing tasks is analyzed in terms of mean response rates.

Development and initial evaluation of the SCI-FI/AT

PubMed Central

Jette, Alan M.; Slavin, Mary D.; Ni, Pengsheng; Kisala, Pamela A.; Tulsky, David S.; Heinemann, Allen W.; Charlifue, Susie; Tate, Denise G.; Fyffe, Denise; Morse, Leslie; Marino, Ralph; Smith, Ian; Williams, Steve

2015-01-01

Objectives To describe the domain structure and calibration of the Spinal Cord Injury Functional Index for samples using Assistive Technology (SCI-FI/AT) and report the initial psychometric properties of each domain. Design Cross sectional survey followed by computerized adaptive test (CAT) simulations. Setting Inpatient and community settings. Participants A sample of 460 adults with traumatic spinal cord injury (SCI) stratified by level of injury, completeness of injury, and time since injury. Interventions None Main outcome measure SCI-FI/AT Results Confirmatory factor analysis (CFA) and Item response theory (IRT) analyses identified 4 unidimensional SCI-FI/AT domains: Basic Mobility (41 items) Self-care (71 items), Fine Motor Function (35 items), and Ambulation (29 items). High correlations of full item banks with 10-item simulated CATs indicated high accuracy of each CAT in estimating a person's function, and there was high measurement reliability for the simulated CAT scales compared with the full item bank. SCI-FI/AT item difficulties in the domains of Self-care, Fine Motor Function, and Ambulation were less difficult than the same items in the original SCI-FI item banks. Conclusion With the development of the SCI-FI/AT, clinicians and investigators have available multidimensional assessment scales that evaluate function for users of AT to complement the scales available in the original SCI-FI. PMID:26010975

Food Insecurity, Socioeconomic Status, and HIV-Related Risk Behavior Among Women in Farming Households in Tanzania

PubMed Central

Ralph, Lauren J.; Njau, Prosper F.; Msolla, Mbette Mshindo; Padian, Nancy S.

2013-01-01

Food insecurity (FI) is associated with higher-risk sexual behavior in some studies. However, the overlap between FI and socioeconomic status (SES) has been poorly described. The study objectives were to: (1) determine the relationship between household FI and four dimensions of SES among sexually active Tanzanian women in farming households: expenditures, assets, flooring material of the home, and land ownership; and (2) determine whether FI is associated with higher-risk sexual behavior and relationship power. In male-headed households, FI was associated with assets, flooring material, and land ownership but not expenditures. There was no association between FI and the four dimensions of SES in female-headed households. Among women in male-headed households, but not female household heads themselves, severe FI was associated with a non-significant increase in the likelihood of being in a relationship because of material goods [adjusted prevalence ratio (PRa) = 1.76, 95 % confidence interval (CI) 0.81, 3.81] and was inversely associated with being able to ask partners to use condoms (PRa = 0.47, 95 % CI 0.25, 0.88). There was not a strong association between food security and relationship power. Our findings suggest that the association between FI and HIV risk behavior may differ depending on the type of household. PMID:24097335

Development and initial evaluation of the SCI-FI/AT.

PubMed

Jette, Alan M; Slavin, Mary D; Ni, Pengsheng; Kisala, Pamela A; Tulsky, David S; Heinemann, Allen W; Charlifue, Susie; Tate, Denise G; Fyffe, Denise; Morse, Leslie; Marino, Ralph; Smith, Ian; Williams, Steve

2015-05-01

To describe the domain structure and calibration of the Spinal Cord Injury Functional Index for samples using Assistive Technology (SCI-FI/AT) and report the initial psychometric properties of each domain. Cross sectional survey followed by computerized adaptive test (CAT) simulations. Inpatient and community settings. A sample of 460 adults with traumatic spinal cord injury (SCI) stratified by level of injury, completeness of injury, and time since injury. None SCI-FI/AT RESULTS: Confirmatory factor analysis (CFA) and Item response theory (IRT) analyses identified 4 unidimensional SCI-FI/AT domains: Basic Mobility (41 items) Self-care (71 items), Fine Motor Function (35 items), and Ambulation (29 items). High correlations of full item banks with 10-item simulated CATs indicated high accuracy of each CAT in estimating a person's function, and there was high measurement reliability for the simulated CAT scales compared with the full item bank. SCI-FI/AT item difficulties in the domains of Self-care, Fine Motor Function, and Ambulation were less difficult than the same items in the original SCI-FI item banks. With the development of the SCI-FI/AT, clinicians and investigators have available multidimensional assessment scales that evaluate function for users of AT to complement the scales available in the original SCI-FI.

Was breaking the taboo on research on climate engineering via albedo modification a moral hazard, or a moral imperative?

NASA Astrophysics Data System (ADS)

Lawrence, Mark G.; Crutzen, Paul J.

2017-02-01

The topic of increasing the reflectivity of the Earth as a measure to counteract global warming has been the subject of high-level discussions and preliminary research since several decades, though prior to the early 2000s there was only very limited research on the topic. This changed in the mid-2000s, particularly following the publication of a special section of Climatic Change with a lead paper by Crutzen [2006], which posited the idea of stratospheric aerosol injections as a possible solution to a policy dilemma. The discussions around the publication of Crutzen [2006] demonstrated how contentious the topic was at that time. The special section of Climatic Change contributed to breaking the "taboo" on albedo modification research that was perceived at that time, and scientific publications on the topic have since proliferated, including the development of several large national and international projects, and the publication of several assessment reports over the last decade. Here we reflect on the background and main conclusions of the publications in 2006, the developments since then, and on some of the main developments over the next decade that we anticipate for research and dialogue in support of decision-making and policy development processes.

Acquisition of Complement Inhibitor Serine Protease Factor I and Its Cofactors C4b-Binding Protein and Factor H by Prevotella intermedia

PubMed Central

Malm, Sven; Jusko, Monika; Eick, Sigrun; Potempa, Jan; Riesbeck, Kristian; Blom, Anna M.

2012-01-01

Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP) and Factor H (FH). Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with 125I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases. PMID:22514678

Acquisition of complement inhibitor serine protease factor I and its cofactors C4b-binding protein and factor H by Prevotella intermedia.

PubMed

Malm, Sven; Jusko, Monika; Eick, Sigrun; Potempa, Jan; Riesbeck, Kristian; Blom, Anna M

2012-01-01

Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP) and Factor H (FH). Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with (125)I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases.

Household food insecurity and symptoms of neurologic disorder in Ethiopia: an observational analysis.

PubMed

El-Sayed, Abdulrahman M; Hadley, Craig; Tessema, Fasil; Tegegn, Ayelew; Cowan, John A; Galea, Sandro

2010-12-31

Food insecurity (FI) has been shown to be associated with poor health both in developing and developed countries. Little is known about the relation between FI and neurological disorder. We assessed the relation between FI and risk for neurologic symptoms in southwest Ethiopia. Data about food security, gender, age, household assets, and self-reported neurologic symptoms were collected from a representative, community-based sample of adults (N = 900) in Jimma Zone, Ethiopia. We calculated univariate statistics and used bivariate chi-square tests and multivariate logistic regression models to assess the relation between FI and risk of neurologic symptoms including seizures, extremity weakness, extremity numbness, tremors/ataxia, aphasia, carpal tunnel syndrome, vision dysfunction, and spinal pain. In separate multivariate models by outcome and gender, adjusting for age and household socioeconomic status, severe FI was associated with higher odds of seizures, movement abnormalities, carpal tunnel, vision dysfunction, spinal pain, and comorbid disorders among women. Severe FI was associated with higher odds of seizures, extremity numbness, movement abnormalities, difficulty speaking, carpal tunnel, vision dysfunction, and comorbid disorders among men. We found that FI was associated with symptoms of neurologic disorder. Given the cross-sectional nature of our study, the directionality of these associations is unclear. Future research should assess causal mechanisms relating FI to neurologic symptoms in sub-Saharan Africa.

Primordial non-Gaussianity and reionization

NASA Astrophysics Data System (ADS)

Lidz, Adam; Baxter, Eric J.; Adshead, Peter; Dodelson, Scott

2013-07-01

The statistical properties of the primordial perturbations contain clues about their origins. Although the Planck collaboration has recently obtained tight constraints on primordial non-Gaussianity from cosmic microwave background measurements, it is still worthwhile to mine upcoming data sets in an effort to place independent or competitive limits. The ionized bubbles that formed at redshift z˜6-20 during the epoch of reionization were seeded by primordial overdensities, and so the statistics of the ionization field at high redshift are related to the statistics of the primordial field. Here we model the effect of primordial non-Gaussianity on the reionization field. The epoch and duration of reionization are affected, as are the sizes of the ionized bubbles, but these changes are degenerate with variations in the properties of the ionizing sources and the surrounding intergalactic medium. A more promising signature is the power spectrum of the spatial fluctuations in the ionization field, which may be probed by upcoming 21 cm surveys. This has the expected 1/k2 dependence on large scales, characteristic of a biased tracer of the matter field. We project how well upcoming 21 cm observations will be able to disentangle this signal from foreground contamination. Although foreground cleaning inevitably removes the large-scale modes most impacted by primordial non-Gaussianity, we find that primordial non-Gaussianity can be separated from foreground contamination for a narrow range of length scales. In principle, futuristic redshifted 21 cm surveys may allow constraints competitive with Planck.

Miniature Ion-Mobility Spectrometer

NASA Technical Reports Server (NTRS)

Hartley, Frank T.

2006-01-01

The figure depicts a proposed miniature ion-mobility spectrometer that would be fabricated by micromachining. Unlike prior ion-mobility spectrometers, the proposed instrument would not be based on a time-of-flight principle and, consequently, would not have some of the disadvantageous characteristics of prior time-of-flight ion-mobility spectrometers. For example, one of these characteristics is the need for a bulky carrier-gas-feeding subsystem that includes a shutter gate to provide short pulses of gas in order to generate short pulses of ions. For another example, there is need for a complex device to generate pulses of ions from the pulses of gas and the device is capable of ionizing only a fraction of the incoming gas molecules; these characteristics preclude miniaturization. In contrast, the proposed instrument would not require a carrier-gas-feeding subsystem and would include a simple, highly compact device that would ionize all the molecules passing through it. The ionization device in the proposed instrument would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several megavolts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. Ionization (but not avalanche arcing) would occur because the distance between the ionizing electrodes would be less than the mean free path of gas molecules at the operating pressure of instrument. An accelerating grid would be located inside the instrument, downstream from the ionizing membrane. The electric potential applied to this grid would be negative relative to the potential on the inside electrode of the ionizing membrane and would be of a magnitude sufficient to generate a moderate electric field. Positive ions leaving the membrane holes would be accelerated in this electric field. The resulting flux of ions away from the ionization membrane would create a partial vacuum that would draw more of the gas medium through the membrane. The figure depicts a filter electrode and detector electrodes located along the sides of a drift tube downstream from the accelerator electrode. These electrodes would apply a transverse AC electric field superimposed on a ramped DC electric field. The AC field would effect differential transverse dispersal of ions. At a given instant of time, the trajectories of most of the ions would be bent toward the electrodes, causing most of the ions to collide with the electrodes and thereby become neutralized. The DC field would partly counteract the dispersive effect of the AC field, straightening the trajectories of a selected species of ions; the selection would vary with the magnitude of the applied DC field. The straightening of the trajectories of the selected ions would enable them to pass into the region between the detector electrodes. Depending on the polarity of the voltage applied to the detector electrodes, the electric field between the detector electrodes would draw the selected ions to one of these electrodes. Hence, the current collected by one of the detector electrodes would be a measure of the abundance of ions of the selected species. The ramping of the filter- electrode DC voltage would sweep the selection of ions through the spectrum of ionic species.

Ultrafast Electron Plasma Index: An Ionization Perspective

DTIC Science & Technology

2014-05-29

picture in mind, the derivation of the index was a combination of the principle of least action and Fermat’s principle. In the current textbook ...multiphoton ionization. Phys Rev Lett 71: 1994-1997. 27. Ivanov MY, Spanner M, Smirnova O (2005) Anatomy of strong field ionization. J. Mod.Phys 52

Transference effects of prior non-contingent reinforcement on the acquisition of temporal control on fixed-interval schedules.

PubMed

López, Florente; Menez, Marina

2012-07-01

In two experiments we examined the influence of response and time factors on the speed of acquisition of temporal control on FI schedules. In Experiment 1, prior exposure to FT accelerated the development of temporal control on FI schedules of the same temporal value. It was also found that the slower acquisition on FI with prior RT was similar to that of rats with prior standard training. In Experiment 2, prior exposure to FT accelerated the development of temporal control on a FI schedule with a threefold increase in temporal value. Additionally, it was found that with prior FI 30s training, acquisition of temporal control on FI 90s was even faster than with prior FT 30s. Measures of head-entries into the feeder along the experiments indicated that temporal control was already developed during the periodic but not during the non-periodic histories and that this control transferred to lever press during FI testing phase. Copyright © 2012 Elsevier B.V. All rights reserved.

Wi-Fi/MARG Integration for Indoor Pedestrian Localization

PubMed Central

Tian, Zengshan; Jin, Yue; Zhou, Mu; Wu, Zipeng; Li, Ze

2016-01-01

With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG) sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR) and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF) based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely. PMID:27973412

Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism

NASA Technical Reports Server (NTRS)

Markson, R.

1980-01-01

The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.

TL dosimetry for quality control of CR mammography imaging systems

NASA Astrophysics Data System (ADS)

Gaona, E.; Nieto, J. A.; Góngora, J. A. I. D.; Arreola, M.; Enríquez, J. G. F.

The aim of this work is to estimate the average glandular dose with thermoluminescent (TL) dosimetry and comparison with quality imaging in computed radiography (CR) mammography. For a measuring dose, the Food and Drug Administration (FDA) and the American College of Radiology (ACR) use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, full field digital mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium flourohalideE We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated X-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose greater than 3.0 mGy without demonstrating improved image quality. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement for X-rays with a HVL (0.35-0.38 mmAl) and kVp (24-26) used in quality control procedures with ACR Mammography Accreditation Phantom.

How important are diapycnal mixing and geothermal heating for the deep circulation of the Western Mediterranean?

NASA Astrophysics Data System (ADS)

Ferron, B.; Bouruet Aubertot, P.; Cuypers, Y.; Schroeder, K.; Borghini, M.

2017-08-01

The dissipation rate of turbulent kinetic energy ɛ and the associated diapycnal turbulent mixing is inferred from a set of microstructure observations collected over several cruises from year 2012 to 2014. The geographical distribution of ɛ highlights several regions of enhanced levels of turbulence ranging from 10-9 to 10-6 W kg-1: the Sicily Channel, the Corsica Channel, and the Ligurian Sea. Elsewhere, ɛ was small, often below 10-10 W kg-1. Below 1300 m, geothermal heating provides three-fold more buoyancy than small-scale turbulence. Geothermal heating and turbulent diffusion provide enough buoyancy to balance 15% to 50% of a mean yearly deep water formation rate of 0.9 to 0.3 sverdrup (106 m3/s), respectively. The remaining part has to eventually overflow through the Strait of Gibraltar.

The Audacity of Fiber-Wireless (FiWi) Networks

NASA Astrophysics Data System (ADS)

Maier, Martin; Ghazisaidi, Navid; Reisslein, Martin

A plethora of enabling optical and wireless technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi) broadband access networks. After overviewing key enabling radio-over-fiber (RoF) and radio-and-fiber (R&F) technologies and briefly surveying the state of the art of FiWi networks, we introduce an Ethernet-based access-metro FiWi network, called SuperMAN, that integrates next-generation WiFi and WiMAX networks with WDM-enhanced EPON and RPR networks. Throughout the paper we pay close attention to the technical challenges and opportunities of FiWi networks, but also elaborate on their societal benefits and potential to shift the current research focus from optical-wireless networking to the exploitation of personal and in-home computing facilities to create new unforeseen services and applications as we are about to enter the Petabyte age.

Clinical interpretation of the Spinal Cord Injury Functional Index (SCI-FI).

PubMed

Fyffe, Denise; Kalpakjian, Claire Z; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Kirshblum, Steven C; Tulsky, David S; Jette, Alan M

2016-09-01

To provide validation of functional ability levels for the Spinal Cord Injury - Functional Index (SCI-FI). Cross-sectional. Inpatient rehabilitation hospital and community settings. A sample of 855 individuals with traumatic spinal cord injury enrolled in 6 rehabilitation centers participating in the National Spinal Cord Injury Model Systems Network. Not Applicable. Spinal Cord Injury-Functional Index (SCI-FI). Cluster analyses identified three distinct groups that represent low, mid-range and high SCI-FI functional ability levels. Comparison of clusters on personal and other injury characteristics suggested some significant differences between groups. These results strongly support the use of SCI-FI functional ability levels to document the perceived functional abilities of persons with SCI. Results of the cluster analysis suggest that the SCI-FI functional ability levels capture function by injury characteristics. Clinical implications regarding tracking functional activity trajectories during follow-up visits are discussed.

10 m/25 Gbps LiFi transmission system based on a two-stage injection-locked 680 nm VCSEL transmitter.

PubMed

Lu, Hai-Han; Li, Chung-Yi; Chu, Chien-An; Lu, Ting-Chien; Chen, Bo-Rui; Wu, Chang-Jen; Lin, Dai-Hua

2015-10-01

A 10  m/25  Gbps light-based WiFi (LiFi) transmission system based on a two-stage injection-locked 680 nm vertical-cavity surface-emitting laser (VCSEL) transmitter is proposed. A LiFi transmission system with a data rate of 25 Gbps is experimentally demonstrated over a 10 m free-space link. To the best of our knowledge, it is the first time a two-stage injection-locked 680 nm VCSEL transmitter in a 10  m/25  Gbps LiFi transmission system has been employed. Impressive bit error rate performance and a clear eye diagram are achieved in the proposed systems. Such a 10  m/25  Gbps LiFi transmission system provides the advantage of a communication link for higher data rates that could accelerate the deployment of visible laser light communication.

Flash ionization signature in coherent cyclotron emission from brown dwarfs

NASA Astrophysics Data System (ADS)

Vorgul, I.; Helling, Ch.

2016-05-01

Brown dwarfs (BDs) form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in the form of lightning resulting in substantial sudden increase of local ionization. BDs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionization events (flash ionization) can be imprinted on a pre-existing radiation. Detection of such flash ionization events will open investigations into the ionization state and atmospheric dynamics. Such events can also result from explosion shock waves, material outbursts or (volcanic) eruptions. We present an analytical model that describes the modulation of a pre-existing electromagnetic radiation by a time-dependent (flash) conductivity that is characteristic for flash ionization events like lightning. Our conductivity model reproduces the conductivity function derived from observations of terrestrial gamma-ray flashes, and is applicable to astrophysical objects with strong temporal variations in the local ionization, as in planetary atmospheres and protoplanetary discs. We show that the field responds with a characteristic flash-shaped pulse to a conductivity flash of intermediate intensity. More powerful ionization events result in smaller variations of the initial radiation, or in its damping. We show that the characteristic damping of the response field for high-power initial radiation carries information about the ionization flash magnitude and duration. The duration of the pulse amplification or the damping is consistently shorter for larger conductivity variations and can be used to evaluate the intensity of the flash ionization. Our work suggests that cyclotron emission could be probe signals for electrification processes inside BD atmosphere.

Assessment of PaO2/FiO2 for stratification of patients with moderate and severe acute respiratory distress syndrome

PubMed Central

Villar, Jesús; Blanco, Jesús; del Campo, Rafael; Andaluz-Ojeda, David; Díaz-Domínguez, Francisco J; Muriel, Arturo; Córcoles, Virgilio; Suárez-Sipmann, Fernando; Tarancón, Concepción; González-Higueras, Elena; López, Julia; Blanch, Lluis; Pérez-Méndez, Lina; Fernández, Rosa Lidia; Kacmarek, Robert M

2015-01-01

Objectives A recent update of the definition of acute respiratory distress syndrome (ARDS) proposed an empirical classification based on ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) at ARDS onset. Since the proposal did not mandate PaO2/FiO2 calculation under standardised ventilator settings (SVS), we hypothesised that a stratification based on baseline PaO2/FiO2 would not provide accurate assessment of lung injury severity. Design A prospective, multicentre, observational study. Setting A network of teaching hospitals. Participants 478 patients with eligible criteria for moderate (100300). Primary and secondary outcomes Group severity and hospital mortality. Results At ARDS onset, 173 patients had a PaO2/FiO2≤100 but only 38.7% met criteria for severe ARDS at 24 h under SVS. When assessed under SVS, 61.3% of patients with severe ARDS were reclassified as moderate, mild and non-ARDS, while lung severity and hospital mortality changed markedly with every PaO2/FiO2 category (p<0.000001). Our model of risk stratification outperformed the stratification using baseline PaO2/FiO2 and non-standardised PaO2/FiO2 at 24 h, when analysed by the predictive receiver operating characteristic (ROC) curve: area under the ROC curve for stratification at baseline was 0.583 (95% CI 0.525 to 0.636), 0.605 (95% CI 0.552 to 0.658) at 24 h without SVS and 0.693 (95% CI 0.645 to 0.742) at 24 h under SVS (p<0.000001). Conclusions Our findings support the need for patient assessment under SVS at 24 h after ARDS onset to assess disease severity, and have implications for the diagnosis and management of ARDS patients. Trial registration numbers NCT00435110 and NCT00736892. PMID:25818272

Assessment of PaO₂/FiO₂ for stratification of patients with moderate and severe acute respiratory distress syndrome.

PubMed

Villar, Jesús; Blanco, Jesús; del Campo, Rafael; Andaluz-Ojeda, David; Díaz-Domínguez, Francisco J; Muriel, Arturo; Córcoles, Virgilio; Suárez-Sipmann, Fernando; Tarancón, Concepción; González-Higueras, Elena; López, Julia; Blanch, Lluis; Pérez-Méndez, Lina; Fernández, Rosa Lidia; Kacmarek, Robert M

2015-03-27

A recent update of the definition of acute respiratory distress syndrome (ARDS) proposed an empirical classification based on ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂) at ARDS onset. Since the proposal did not mandate PaO₂/FiO₂ calculation under standardised ventilator settings (SVS), we hypothesised that a stratification based on baseline PaO₂/FiOv would not provide accurate assessment of lung injury severity. A prospective, multicentre, observational study. A network of teaching hospitals. 478 patients with eligible criteria for moderate (100300). Group severity and hospital mortality. At ARDS onset, 173 patients had a PaO₂/FiO₂≤100 but only 38.7% met criteria for severe ARDS at 24 h under SVS. When assessed under SVS, 61.3% of patients with severe ARDS were reclassified as moderate, mild and non-ARDS, while lung severity and hospital mortality changed markedly with every PaO₂/FiO₂ category (p<0.000001). Our model of risk stratification outperformed the stratification using baseline PaO₂/FiO₂ and non-standardised PaO₂/FiO₂ at 24 h, when analysed by the predictive receiver operating characteristic (ROC) curve: area under the ROC curve for stratification at baseline was 0.583 (95% CI 0.525 to 0.636), 0.605 (95% CI 0.552 to 0.658) at 24 h without SVS and 0.693 (95% CI 0.645 to 0.742) at 24 h under SVS (p<0.000001). Our findings support the need for patient assessment under SVS at 24 h after ARDS onset to assess disease severity, and have implications for the diagnosis and management of ARDS patients. NCT00435110 and NCT00736892. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Measurements of the energy distribution of a high brightness rubidium ion beam.

PubMed

Ten Haaf, G; Wouters, S H W; Nijhof, D F J; Mutsaers, P H A; Vredenbregt, E J D

2018-07-01

The energy distribution of a high brightness rubidium ion beam, which is intended to be used as the source for a focused ion beam instrument, is measured with a retarding field analyzer. The ions are created from a laser-cooled and compressed atomic beam by two-step photoionization in which the ionization laser power is enhanced in a build-up cavity. Particle tracing simulations are performed to ensure the analyzer is able to resolve the distribution. The lowest achieved full width 50% energy spread is (0.205 ± 0.006) eV, which is measured at a beam current of 9 pA. The energy spread originates from the variation in the ionization position of the ions which are created inside an extraction electric field. This extraction field is essential to limit disorder-induced heating which can decrease the ion beam brightness. The ionization position distribution is limited by a tightly focused excitation laser beam. Energy distributions are measured for various ionization and excitation laser intensities and compared with calculations based on numerical solutions of the optical Bloch equations including ionization. A good agreement is found between measurements and calculations. Copyright © 2018 Elsevier B.V. All rights reserved.

Modeling of Microplasmas with Nano-Engineered Electrodes

NASA Astrophysics Data System (ADS)

Macheret, Sergey; Tholeti, Siva Shashank; Alexeenko, Alina

2015-09-01

Microplasmas can potentially be used as unique tunable dielectrics for reconfigurable radio-frequency systems, if electron densities of 1010-1012 cm-3 can be sustained in cavities smaller than 100 micron. However, for low loss tangent, gas pressures below 10 mTorr would be required, whereas the physics of electron impact ionization dictates the pd scaling so that microplasmas must operate at high gas pressures, hundreds of Torr, and also high voltages. We analyze a new principle of plasma generation that goes well beyond the pd scaling by eliminating electron impact ionization. In the new concept, electrons are generated at the cathode by field emission from nanotubes, and ions are independently produced in field ionization at atomically-sharp tips on the anode. The electrons and ions then move in the opposite directions, mix, and create a plasma. The low pressure results in collisionless motion with no electron-impact ionization. One-dimensional PIC/MCC calculations show that emitters such as carbon nanotubes placed sparsely on the cathode, combined with field ionization nanorods at the anode, can indeed ensure steady-state electron densities of up to 1012 cm-3 at gas pressure lower than 10 mTorr with only 50-100 Volts applied cross a 40-50 μm gap.

Unraveling nonadiabatic ionization and Coulomb potential effect in strong-field photoelectron holography.

PubMed

Song, Xiaohong; Lin, Cheng; Sheng, Zhihao; Liu, Peng; Chen, Zhangjin; Yang, Weifeng; Hu, Shilin; Lin, C D; Chen, Jing

2016-06-22

Strong field photoelectron holography has been proposed as a means for interrogating the spatial and temporal information of electrons and ions in a dynamic system. After ionization, part of the electron wave packet may directly go to the detector (the reference wave), while another part may be driven back and scatters off the ion(the signal wave). The interference hologram of the two waves may be used to extract target information embedded in the collision process. Unlike conventional optical holography, however, propagation of the electron wave packet is affected by the Coulomb potential as well as by the laser field. In addition, electrons are emitted over the whole laser pulse duration, thus multiple interferences may occur. In this work, we used a generalized quantum-trajectory Monte Carlo method to investigate the effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram. We showed that photoelectron hologram can be well described only when the effect of nonadiabatic ionization is accounted for, and Coulomb potential can be neglected only in the tunnel ionization regime. Our results help paving the way for establishing photoelectron holography for probing spatial and dynamic properties of atoms and molecules.

Unraveling nonadiabatic ionization and Coulomb potential effect in strong-field photoelectron holography

PubMed Central

Song, Xiaohong; Lin, Cheng; Sheng, Zhihao; Liu, Peng; Chen, Zhangjin; Yang, Weifeng; Hu, Shilin; Lin, C. D.; Chen, Jing

2016-01-01

Strong field photoelectron holography has been proposed as a means for interrogating the spatial and temporal information of electrons and ions in a dynamic system. After ionization, part of the electron wave packet may directly go to the detector (the reference wave), while another part may be driven back and scatters off the ion(the signal wave). The interference hologram of the two waves may be used to extract target information embedded in the collision process. Unlike conventional optical holography, however, propagation of the electron wave packet is affected by the Coulomb potential as well as by the laser field. In addition, electrons are emitted over the whole laser pulse duration, thus multiple interferences may occur. In this work, we used a generalized quantum-trajectory Monte Carlo method to investigate the effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram. We showed that photoelectron hologram can be well described only when the effect of nonadiabatic ionization is accounted for, and Coulomb potential can be neglected only in the tunnel ionization regime. Our results help paving the way for establishing photoelectron holography for probing spatial and dynamic properties of atoms and molecules. PMID:27329071

Unraveling nonadiabatic ionization and Coulomb potential effect in strong-field photoelectron holography

DOE PAGES

Song, Xiaohong; Lin, Cheng; Sheng, Zhihao; ...

2016-06-22

Strong field photoelectron holography has been proposed as a means for interrogating the spatial and temporal information of electrons and ions in a dynamic system. After ionization, part of the electron wave packet may directly go to the detector (the reference wave), while another part may be driven back and scatters off the ion(the signal wave). The interference hologram of the two waves may be used to extract target information embedded in the collision process. Unlike conventional optical holography, however, propagation of the electron wave packet is affected by the Coulomb potential as well as by the laser field. Inmore » addition, electrons are emitted over the whole laser pulse duration, thus multiple interferences may occur. In this work, we used a generalized quantum-trajectory Monte Carlo method to investigate the effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram. Here, we showed that photoelectron hologram can be well described only when the effect of nonadiabatic ionization is accounted for, and Coulomb potential can be neglected only in the tunnel ionization regime. Our results help paving the way for establishing photoelectron holography for probing spatial and dynamic properties of atoms and molecules.« less

E-beam ionized channel guiding of an intense relativistic electron beam

DOEpatents

Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

1988-05-10

An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path. 2 figs.

Dark Matter Detection Using Helium Evaporation and Field Ionization

NASA Astrophysics Data System (ADS)

Maris, Humphrey J.; Seidel, George M.; Stein, Derek

2017-11-01

We describe a method for dark matter detection based on the evaporation of helium atoms from a cold surface and their subsequent detection using field ionization. When a dark matter particle scatters off a nucleus of the target material, elementary excitations (phonons or rotons) are produced. Excitations which have an energy greater than the binding energy of helium to the surface can result in the evaporation of helium atoms. We propose to detect these atoms by ionizing them in a strong electric field. Because the binding energy of helium to surfaces can be below 1 meV, this detection scheme opens up new possibilities for the detection of dark matter particles in a mass range down to 1 MeV /c2 .

Dark Matter Detection Using Helium Evaporation and Field Ionization.

PubMed

Maris, Humphrey J; Seidel, George M; Stein, Derek

2017-11-03

We describe a method for dark matter detection based on the evaporation of helium atoms from a cold surface and their subsequent detection using field ionization. When a dark matter particle scatters off a nucleus of the target material, elementary excitations (phonons or rotons) are produced. Excitations which have an energy greater than the binding energy of helium to the surface can result in the evaporation of helium atoms. We propose to detect these atoms by ionizing them in a strong electric field. Because the binding energy of helium to surfaces can be below 1 meV, this detection scheme opens up new possibilities for the detection of dark matter particles in a mass range down to 1  MeV/c^{2}.

Pulsed ion beam source

DOEpatents

Greenly, J.B.

1997-08-12

An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

Separation of Opiate Isomers Using Electrospray Ionization and Paper Spray Coupled to High-Field Asymmetric Waveform Ion Mobility Spectrometry

NASA Astrophysics Data System (ADS)

Manicke, Nicholas E.; Belford, Michael

2015-05-01

One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphone, and norcodeine. These isomers cannot be distinguished by tandem mass spectrometry. Separation prior to MS analysis is, therefore, required to distinguish these compounds, which are important in clinical chemistry and toxicology. FAIMS was coupled to a triple quadrupole mass spectrometer, and ionization was performed using either a pneumatically assisted heated electrospray ionization source (H-ESI) or paper spray, a direct analysis method that has been applied to the direct analysis of dried blood spots and other complex samples. We found that FAIMS was capable of separating the three opiate structural isomers using both H-ESI and paper spray as the ionization source.

ETP-0492, Measured Residual Stresses in CYL S/N 53 Fretted Area

NASA Technical Reports Server (NTRS)

Webster, Ronald L.

1998-01-01

This test report presents the results of a residual stress survey of the inner clevis leg of lightweight cylinder SIN 053 as described by ETP-0492. The intent of this testing was to evaluate the residual stresses that occur in and around the inner clevis leg at the capture feature contact zone during a normal flight cycle. Lightweight case cylinder segment IU50717, S/N L053 from Flight STS-27 exhibited fretting around the contact zone of the inner clevis leg and the capture feature of the field joint. Post flight inspection revealed several large fitting pits on the inside of the inner clevis leg. This cylinder was assigned for both residual stress and metallurgical evaluation. This report is concerned only with the residual so= evaluations. The effects of glass bead cleaning and fi=ing were evaluated using the x-ray diffraction method.

Sensory empathy and enactment.

PubMed

Zanocco, Giorgio; De Marchi, Alessandra; Pozzi, Francesco

2006-02-01

The authors propose the concept of sensory empathy which emerges through contact between analyst and patient as they get in touch with an area concerning the primary bond. This area is not so much based on thoughts and fantasies as it is on physical sensations. Sensory empathy has to do with that instrument described by Freud as pertaining to the unconscious of any human, which enables one person to interpret unconscious communications of another person. The authors link this concept to that of enactment precisely because the latter concerns unconscious, early elements that fi nd in the act a fi rst meaningful expression. It involves both analyst and patient. In other words, the authors wish to emphasize the importance of the analytical process maintaining contact with that immense field of human interaction that can be defined as primary sensory area and which becomes intertwined with the evolution of affects. Clinical examples are provided to clarify these hypotheses.

Exploitation of Ubiquitous Wi-Fi Devices as Building Blocks for Improvised Motion Detection Systems.

PubMed

Soldovieri, Francesco; Gennarelli, Gianluca

2016-02-27

This article deals with a feasibility study on the detection of human movements in indoor scenarios based on radio signal strength variations. The sensing principle exploits the fact that the human body interacts with wireless signals, introducing variations of the radiowave fields due to shadowing and multipath phenomena. As a result, human motion can be inferred from fluctuations of radiowave power collected by a receiving terminal. In this paper, we investigate the potentialities of widely available wireless communication devices in order to develop an improvised motion detection system (IMDS). Experimental tests are performed in an indoor environment by using a smartphone as a Wi-Fi access point and a laptop with dedicated software as a receiver. Simple detection strategies tailored for real-time operation are implemented to process the received signal strength measurements. The achieved results confirm the potentialities of the simple system here proposed to reliably detect human motion in operational conditions.

The Fundamental Reasons Why Laptop Computers should not be Used on Your Lap.

PubMed

Mortazavi, S A R; Taeb, S; Mortazavi, S M J; Zarei, S; Haghani, M; Habibzadeh, P; Shojaei-Fard, M B

2016-12-01

As a tendency to use new technologies, gadgets such as laptop computers are becoming more popular among students, teachers, businessmen and office workers. Today laptops are a great tool for education and learning, work and personal multimedia. Millions of men, especially those in the reproductive age, are frequently using their laptop computers on the lap (thigh). Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and Magnetic Resonance Imaging (MRI). Our own studies as well as the studies performed by other researchers indicate that using laptop computers on the lap adversely affects the male reproductive health. When it is placed on the lap, not only the heat from a laptop computer can warm men's scrotums, the electromagnetic fields generated by laptop's internal electronic circuits as well as the Wi-Fi Radiofrequency radiation hazards (in a Wi-Fi connected laptop) may decrease sperm quality. Furthermore, due to poor working posture, laptops should not be used on the lap for long hours.

The Fundamental Reasons Why Laptop Computers should not be Used on Your Lap

PubMed Central

Mortazavi, S.A.R.; Taeb, S.; Mortazavi, S.M.J.; Zarei, S.; Haghani, M.; Habibzadeh, P.; Shojaei-fard, M.B.

2016-01-01

As a tendency to use new technologies, gadgets such as laptop computers are becoming more popular among students, teachers, businessmen and office workers. Today laptops are a great tool for education and learning, work and personal multimedia. Millions of men, especially those in the reproductive age, are frequently using their laptop computers on the lap (thigh). Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and Magnetic Resonance Imaging (MRI). Our own studies as well as the studies performed by other researchers indicate that using laptop computers on the lap adversely affects the male reproductive health. When it is placed on the lap, not only the heat from a laptop computer can warm men’s scrotums, the electromagnetic fields generated by laptop’s internal electronic circuits as well as the Wi-Fi Radiofrequency radiation hazards (in a Wi-Fi connected laptop) may decrease sperm quality. Furthermore, due to poor working posture, laptops should not be used on the lap for long hours. PMID:28144597

The Use of Classroom Assessment to Explore Problem Solving Skills Based on Pre-Service Teachers’ Cognitive Style Dimension in Basic Physics Course

NASA Astrophysics Data System (ADS)

Rahmawati; Rustaman, Nuryani Y.; Hamidah, Ida; Rusdiana, Dadi

2017-02-01

The aim of this study was to explore the use of assessment strategy which can measure problem solving skills of pre-service teachers based on their cognitive style in basic physics course. The sample consisted of 95 persons (male = 15, female = 75). This study used an exploratory research with observation techniques by interview, questionnaire, and test. The results indicated that the lecturer only used paper-pencil test assessment strategy to measure pre-service teachers’ achievement and also used conventional learning strategy. It means that the lecturer did not measure pre-services’ thinking process in learning, like problem solving skills. One of the factors which can influence student problem solving skills is cognitive style as an internal factor. Field Dependent (FD) and Field Independent (FI) are two cognitive styles which were measured with using Group Embedded Figure Test (GEFT) test. The result showed that 82% of pre-service teachers were FD cognitive style and only 18% of pre-service teachers had FI cognitive style. Furthermore, these findings became the fundamental design to develop a problem solving assessment model to measure pre-service teachers’ problem solving skills and process in basic physics course.

From Not-So-Great to Worse: The Myth of Best Practice Methodologies

DTIC Science & Technology

2016-09-13

Collins’ arguments and suggested principled commonalities about great fi rms were unsupported. Resnick and Smunt conducted a fi nancial analysis over... market performance according to Collins’ measure, and that none do so when measured according to a metric based on modern portfolio theory. We...applying the fi ve principles to other fi rms or time periods will lead to anything other than average results.” By the way, Col- lins’ list of 11 great

A Unified Access Model for Interconnecting Heterogeneous Wireless Networks

DTIC Science & Technology

2015-05-01

Defined Networking, OpenFlow, WiFi, LTE 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 18 19a. NAME OF...Machine Configurations with WiFi and LTE 4 2.3 Three Virtual Machine Configurations with WiFi and LTE 5 3. Results and Discussion 5 4. Summary and...WiFi and long-term evolution ( LTE ), and created a communication pathway between them via a central controller node. Our simulation serves as a

Wintertime Overnight NOx Removal in a Southeastern United States Coal-fired Power Plant Plume: A Model for Understanding Winter NOx Processing and its Implications

NASA Astrophysics Data System (ADS)

Fibiger, Dorothy L.; McDuffie, Erin E.; Dubé, William P.; Aikin, Kenneth C.; Lopez-Hilfiker, Felipe D.; Lee, Ben H.; Green, Jaime R.; Fiddler, Marc N.; Holloway, John S.; Ebben, Carlena; Sparks, Tamara L.; Wooldridge, Paul; Weinheimer, Andrew J.; Montzka, Denise D.; Apel, Eric C.; Hornbrook, Rebecca S.; Hills, Alan J.; Blake, Nicola J.; DiGangi, Josh P.; Wolfe, Glenn M.; Bililign, Solomon; Cohen, Ronald C.; Thornton, Joel A.; Brown, Steven S.

2018-01-01

Nitric oxide (NO) is emitted in large quantities from coal-burning power plants. During the day, the plumes from these sources are efficiently mixed into the boundary layer, while at night, they may remain concentrated due to limited vertical mixing during which they undergo horizontal fanning. At night, the degree to which NO is converted to HNO3 and therefore unable to participate in next-day ozone (O3) formation depends on the mixing rate of the plume, the composition of power plant emissions, and the composition of the background atmosphere. In this study, we use observed plume intercepts from the Wintertime INvestigation of Transport, Emissions and Reactivity campaign to test sensitivity of overnight NOx removal to the N2O5 loss rate constant, plume mixing rate, background O3, and background levels of volatile organic compounds using a 2-D box model of power plant plume transport and chemistry. The factor that exerted the greatest control over NOx removal was the loss rate constant of N2O5. At the lowest observed N2O5 loss rate constant, no other combination of conditions converts more than 10% of the initial NOx to HNO3. The other factors did not influence NOx removal to the same degree.

Time-dependent density-functional theory with optimized effective potential and self-interaction correction and derivative discontinuity for the treatment of double ionization of He and Be atoms in intense laser fields

NASA Astrophysics Data System (ADS)

Heslar, John; Telnov, Dmitry A.; Chu, Shih-I.

2013-05-01

We present a self-interaction-free time-dependent density-functional theory (TDDFT) for the treatment of double-ionization processes of many-electron systems. The method is based on the extension of the Krieger-Li-Iafrate (KLI) treatment of the optimized effective potential (OEP) theory and the incorporation of an explicit self-interaction correction (SIC) term. In the framework of the time-dependent density functional theory, we have performed three-dimensional (3D) calculations of double ionization of He and Be atoms by intense near-infrared laser fields. We make use of the exchange-correlation potential with the integer discontinuity which improves the description of the double-ionization process. We found that a proper description of the double ionization requires the TDDFT exchange-correlation potential with the discontinuity with respect to the variation of the total particle number (TPN). The results for the intensity-dependent rates of double ionization of He and Be atoms are presented.

Blocking of opioid receptors in experimental formaline-inactivated respiratory syncytial virus (FI-RSV) immunopathogenesis: from beneficial to harmful impacts.

PubMed

Salimi, Vahid; Mirzaei, Habib; Ramezani, Ali; Tahamtan, Alireza; Jamali, Abbas; Shahabi, Shahram; Golaram, Maryam; Minaei, Bagher; Gharagozlou, Mohammad Javad; Mahmoodi, Mahmood; Bont, Louis; Shokri, Fazel; Mokhtari-Azad, Talat

2018-04-01

Opioid system plays a significant role in pathophysiological processes, such as immune response and impacts on disease severity. Here, we investigated the effect of opioid system on the immunopathogenesis of respiratory syncytial virus (RSV) vaccine (FI-RSV)-mediated illness in a widely used mouse model. Female Balb/c mice were immunized at days 0 and 21 with FI-RSV (2 × 10 6  pfu, i.m.) and challenged with RSV-A2 (3 × 10 6  pfu, i.n.) at day 42. Nalmefene as a universal opioid receptors blocker administered at a dose of 1 mg/kg in combination with FI-RSV (FI-RSV + NL), and daily after live virus challenge (RSV + NL). Mice were sacrificed at day 5 after challenge and bronchoalveolar lavage (BAL) fluid and lungs were harvested to measure airway immune cells influx, T lymphocyte subtypes, cytokines/chemokines secretion, lung histopathology, and viral load. Administration of nalmefene in combination with FI-RSV (FI-RSV + NL-RSV) resulted in the reduction of the immune cells infiltration to the BAL fluid, the ratio of CD4/CD8 T lymphocyte, the level of IL-5, IL-10, MIP-1α, lung pathology, and restored weight loss after RSV infection. Blocking of opioid receptors during RSV infection in vaccinated mice (FI-RSV-RSV + NL) had no significant effects on RSV immunopathogenesis. Moreover, administration of nalmefene in combination with FI-RSV and blocking opioid receptors during RSV infection (FI-RSV + NL-RSV + NL) resulted in an increased influx of the immune cells to the BAL fluid, increases the level of IFN-γ, lung pathology, and weight loss in compared to control condition. Although nalmefene administration within FI-RSV vaccine decreases vaccine-enhanced infection during subsequent exposure to the virus, opioid receptor blocking during RSV infection aggravates the host inflammatory response to RSV infection. Thus, caution is required due to beneficial/harmful functions of opioid systems while targeting as potentially therapies.

Drug discrimination under two concurrent fixed-interval fixed-interval schedules.

PubMed

McMillan, D E; Li, M

2000-07-01

Pigeons were trained to discriminate 5.0 mg/kg pentobarbital from saline under a two-key concurrent fixed-interval (FI) 100-s FI 200-s schedule of food presentation, and later tinder a concurrent FI 40-s FI 80-s schedule, in which the FI component with the shorter time requirement reinforced responding on one key after drug administration (pentobarbital-biased key) and on the other key after saline administration (saline-biased key). After responding stabilized under the concurrent FI 100-s FI 200-s schedule, pigeons earned an average of 66% (after pentobarbital) to 68% (after saline) of their reinforcers for responding under the FI 100-s component of the concurrent schedule. These birds made an average of 70% of their responses on both the pentobarbital-biased key after the training dose of pentobarbital and the saline-biased key after saline. After responding stabilized under the concurrent FI 40-s FI 80-s schedule, pigeons earned an average of 67% of their reinforcers for responding under the FI 40 component after both saline and the training dose of pentobarbital. These birds made an average of 75% of their responses on the pentobarbital-biased key after the training dose of pentobarbital, but only 55% of their responses on the saline-biased key after saline. In test sessions preceded by doses of pentobarbital, chlordiazepoxide, ethanol, phencyclidine, or methamphetamine, the dose-response curves were similar under these two concurrent schedules. Pentobarbital, chlordiazepoxide, and ethanol produced dose-dependent increases in responding on the pentobarbital-biased key as the doses increased. For some birds, at the highest doses of these drugs, the dose-response curve turned over. Increasing doses of phencyclidine produced increased responding on the pentobarbital-biased key in some, but not all, birds. After methamphetamine, responding was largely confined to the saline-biased key. These data show that pigeons can perform drug discriminations under concurrent schedules in which the reinforcement frequency under the schedule components differs only by a factor of two, and that when other drugs are substituted for the training drugs they produce dose-response curves similar to the curves produced by these drugs under other concurrent interval schedules.

Wi-Fi is an important threat to human health.

PubMed

Pall, Martin L

2018-07-01

Repeated Wi-Fi studies show that Wi-Fi causes oxidative stress, sperm/testicular damage, neuropsychiatric effects including EEG changes, apoptosis, cellular DNA damage, endocrine changes, and calcium overload. Each of these effects are also caused by exposures to other microwave frequency EMFs, with each such effect being documented in from 10 to 16 reviews. Therefore, each of these seven EMF effects are established effects of Wi-Fi and of other microwave frequency EMFs. Each of these seven is also produced by downstream effects of the main action of such EMFs, voltage-gated calcium channel (VGCC) activation. While VGCC activation via EMF interaction with the VGCC voltage sensor seems to be the predominant mechanism of action of EMFs, other mechanisms appear to have minor roles. Minor roles include activation of other voltage-gated ion channels, calcium cyclotron resonance and the geomagnetic magnetoreception mechanism. Five properties of non-thermal EMF effects are discussed. These are that pulsed EMFs are, in most cases, more active than are non-pulsed EMFs; artificial EMFs are polarized and such polarized EMFs are much more active than non-polarized EMFs; dose-response curves are non-linear and non-monotone; EMF effects are often cumulative; and EMFs may impact young people more than adults. These general findings and data presented earlier on Wi-Fi effects were used to assess the Foster and Moulder (F&M) review of Wi-Fi. The F&M study claimed that there were seven important studies of Wi-Fi that each showed no effect. However, none of these were Wi-Fi studies, with each differing from genuine Wi-Fi in three distinct ways. F&M could, at most conclude that there was no statistically significant evidence of an effect. The tiny numbers studied in each of these seven F&M-linked studies show that each of them lack power to make any substantive conclusions. In conclusion, there are seven repeatedly found Wi-Fi effects which have also been shown to be caused by other similar EMF exposures. Each of the seven should be considered, therefore, as established effects of Wi-Fi. Copyright © 2018 The Author. Published by Elsevier Inc. All rights reserved.

Mass-loss rates, ionization fractions, shock velocities, and magnetic fields of stellar jets

NASA Technical Reports Server (NTRS)

Hartigan, Patrick; Morse, Jon A.; Raymond, John

1994-01-01

In this paper we calculate emission-line ratios from a series of planar radiative shock models that cover a wide range of shock velocities, preshock densities, and magnetic fields. The models cover the initial conditions relevant to stellar jets, and we show how to estimate the ionization fractions and shock velocities in jets directly from observations of the strong emission lines in these flows. The ionization fractions in the HH 34, HH 47, and HH 111 jets are approximately 2%, considerably smaller than previous estimates, and the shock velocities are approximately 30 km/s. For each jet the ionization fractions were found from five different line ratios, and the estimates agree to within a factor of approximately 2. The scatter in the estimates of the shock velocities is also small (+/- 4 km/s). The low ionization fractions of stellar jets imply that the observed electron densities are much lower than the total densities, so the mass-loss rates in these flows are correspondingly higher (approximately greater than 2 x 10(exp -7) solar mass/yr). The mass-loss rates in jets are a significant fraction (1%-10%) of the disk accretion rates onto young stellar objects that drive the outflows. The momentum and energy supplied by the visible portion of a typical stellar jet are sufficient to drive a weak molecular outflow. Magnetic fields in stellar jets are difficult to measure because the line ratios from a radiative shock with a magnetic field resemble those of a lower velocity shock without a field. The observed line fluxes can in principle indicate the strength of the field if the geometry of the shocks in the jet is well known.

Atomic physics effects on tokamak edge drift-tearing modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahm, T.S.

1993-03-01

The effects of ionization and charge exchange on the linear stability of drift-tearing modes are analytically investigated. In particular, the linear instability threshold {Delta}{sup Th}, produced by ion sound wave coupling is modified. In the strongly collisional regime, the ionization breaks up the near cancellation of the perturbed electric field and the pressure gradient along the magnetic field, and increases the threshold. In the semi-collisional regime, both ionization and charge exchange act as drag on the ion parallel velocity, and consequently decrease the threshold by reducing the effectiveness of ion sound wave propagation.

Atomic physics effects on tokamak edge drift-tearing modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahm, T.S.

1993-03-01

The effects of ionization and charge exchange on the linear stability of drift-tearing modes are analytically investigated. In particular, the linear instability threshold [Delta][sup Th], produced by ion sound wave coupling is modified. In the strongly collisional regime, the ionization breaks up the near cancellation of the perturbed electric field and the pressure gradient along the magnetic field, and increases the threshold. In the semi-collisional regime, both ionization and charge exchange act as drag on the ion parallel velocity, and consequently decrease the threshold by reducing the effectiveness of ion sound wave propagation.

Ionizing gas breakdown waves in strong electric fields.

NASA Technical Reports Server (NTRS)

Klingbeil, R.; Tidman, D. A.; Fernsler, R. F.

1972-01-01

A previous analysis by Albright and Tidman (1972) of the structure of an ionizing potential wave driven through a dense gas by a strong electric field is extended to include atomic structure details of the background atoms and radiative effects, especially, photoionization. It is found that photoionization plays an important role in avalanche propagation. Velocities, electron densities, and temperatures are presented as a function of electric field for both negative and positive breakdown waves in nitrogen.

Improved field emission properties of carbon nanotubes grown on stainless steel substrate and its application in ionization gauge

NASA Astrophysics Data System (ADS)

Li, Detian; Cheng, Yongjun; Wang, Yongjun; Zhang, Huzhong; Dong, Changkun; Li, Da

2016-03-01

Vertically aligned carbon nanotube (CNT) arrays were fabricated by chemical vapor deposition (CVD) technique on different substrates. Microstructures and field emission characteristics of the as-grown CNT arrays were investigated systematically, and its application in ionization gauge was also evaluated preliminarily. The results indicate that the as-grown CNT arrays are vertically well-aligned relating to the substrate surfaces, but the CNTs grown on stainless steel substrate are longer and more crystalline than the ones grown on silicon wafer substrate. The field emission behaviors of the as-grown CNT arrays are strongly dependent upon substrate properties. Namely, the CNT array grown on stainless steel substrate has better field emission properties, including lower turn on and threshold fields, better emission stability and repeatability, compared with the one grown on silicon wafer substrate. The superior field emission properties of the CNT array grown on stainless steel substrate are mainly attributed to low contact resistance, high thermal conductivity, good adhesion strength, etc. In addition, the metrological behaviors of ionization gauge with the CNT array grown on stainless steel substrate as an electron source were investigated, and this novel cathode ionization gauge extends the lower limit of linear pressure measurement to 10-8 Pa, which is one order of magnitude lower than the result reported for the same of gauge with CNT cathode.

Manometric and ultrasonographic characteristics of patients with coexisting fecal incontinence and constipation.

PubMed

Somers, M; Peleman, C; Van Malderen, K; Verlinden, W; Francque, S; De Schepper, H

2017-01-01

The treatment of fecal incontinence (FI) depends upon the dominant pathophysiology: impaired sphincter contractility or overflow due to pelvic floor dyssynergia and insufficient rectal emptying. In this study, we aimed to define the manometric and anorectal ultrasound characteristics in FI patients with and without constipation. We did a retrospective study of 365 anal manometries, performed between October 2012 and July 2015, in patients with FI. Clinical information was obtained from questionnaires. In 220 of these patients an anorectal ultrasound was also available. Key results : A high prevalence of self-reported constipation was seen in the total population of FI patients (66%). This number was lower (31%) when Rome IV criteria were applied. A very high percentage of manometric pelvic floor dyssynergia was seen in the total population with FI (81%). However, patients with FI and constipation did not show pelvic floor dyssynergia more often than patients without constipation. Anal resting pressure, squeeze pressure and anorectal pressure sensitivity were not different when comparing patients without and with constipation. The prevalence of a functional defecation disorder (FDD) in our study population of FI patients was 20%. Wexner score in this subgroup was lower compared with patients without FDD. Anal sphincter defects were more prevalent in women than men, and were associated with diminished sphincter contractility. A very high percentage of FI patients showed manometric pelvic floor dyssynergia. The coexistence of fecal incontinence and constipation did not increase this percentage. Constipation is a frequent and underestimated cause of FI. A correct diagnosis has a major impact on treatment. We aimed to characterize the manometric and transrectal ultrasound profile of FI patients with and without signs of coexisting constipation. - A very high percentage of incontinent patients showed pelvic floor dyssynergia, however no significant difference between the group with and the group without constipation was seen. Anal resting pressure, squeeze pressure and anorectal pressure sensitivity did not differ significantly either. © Acta Gastro-Enterologica Belgica.

Exercise modality modulates body temperature regulation during exercise in uncompensable heat stress.

PubMed

Schlader, Zachary J; Raman, Aaron; Morton, R Hugh; Stannard, Stephen R; Mündel, Toby

2011-05-01

This study evaluated exercise modality [i.e. self-paced (SP) or fixed-intensity (FI) exercise] as a modulator of body temperature regulation under uncompensable heat stress. Eight well-trained male cyclists completed (work-matched) FI and SP cycling exercise bouts in a hot (40.6 ± 0.2°C) and dry (relative humidity 23 ± 3%) environment estimated to elicit 70% of [Formula: see text]O(2)max. Exercise intensity (i.e. power output) decreased over time in SP, which resulted in longer exercise duration (FI 20.3 ± 3.4 min, SP 23.2 ± 4.1 min). According to the heat strain index, the modification of exercise intensity in SP improved the compensability of the thermal environment which, relative to FI, was likely a result of the reductions in metabolic heat production (i.e. [Formula: see text]O(2)). Consequently, the rate of rise in core body temperature was higher in FI (0.108 ± 0.020°C/min) than in SP (0.082 ± 0.016°C/min). Interestingly, cardiac output, stroke volume, and heart rate during exercise were independent of exercise modality. However, core body temperature (FI 39.4 ± 0.3°C, SP 39.1 ± 0.4°C), blood lactate (FI 2.9 ± 0.8 mmol/L, SP 2.3 ± 0.7 mmol/L), perceived exertion (FI 18 ± 2, SP 16 ± 2), and physiological strain (FI 9.1 ± 0.9, SP 8.3 ± 1.1) were all higher in FI compared to SP at exhaustion/completion. These findings indicate that, when exercise is SP, behavioral modification of metabolic heat production improves the compensability of the thermal environment and reduces thermoregulatory strain. Therefore, under uncompensable heat stress, exercise modality modulates body temperature regulation.

Food insecurity and maternal mental health in León, Nicaragua: Potential limitations on the moderating role of social support.

PubMed

Piperata, Barbara A; Schmeer, Kammi K; Rodrigues, Andres Herrera; Salazar Torres, Virgilio Mariano

2016-12-01

Poor mental health among those living in poverty is a serious global public health concern. Food insecurity (FI) is recognized as an important, yet critically understudied social determinant of mental health. The relationship between FI and mothers' mental health in low- and middle-income countries (LMIC) is especially important to understand considering the high rates of poverty and associated FI in these settings. For these mothers, social support may serve as a buffer in ameliorating the impact of FI on mental distress. However, data required to understand these relationships in LMIC remain sparse. To address this gap we used quantitative and qualitative data and convergence parallel analysis to assess: the association between FI and maternal mental distress; and, whether three forms of social support - mother's general social network support and family support (spouse/partner living in the home, parents/in-laws living in the home) - moderated the association. A survey that included data on FI (ELCSA) and mental distress (SRQ-20) was administered to a population-based sample of mothers in León, Nicaragua (n = 434) in 2012. The survey was complemented by data from 6 focus groups. Regression models identified a strong positive relationship between household-level FI and maternal distress. Evidence of social support moderation was mixed: while maternal social network and spousal/partner support did not moderate this relationship, parental support did. Our ethnographic data revealed three themes that help explain these findings: FI is embarrassing/shameful, close family is the most appropriate source of social support and, fear of gossip and ridicule limit the buffering capacity of the social support network. Our findings contribute to a growing literature demonstrating that FI is an important social determinant of maternal mental distress in LMIC; and that some forms of social support may reduce (but not eliminate) the impact of FI on mental distress. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Design of WORKER'S Behavior Analysis Method in Workplace Using Indoor Positioning Technology

NASA Astrophysics Data System (ADS)

Tabata, K.; Konno, H.; Nakajima, M.

2016-06-01

This study presents a method for analyzing workers' behavior using indoor positioning technology and field test in the workplace. Recently, various indoor positioning methods, such as Wi-Fi, Bluetooth low energy (BLE), visible light communication, Japan's indoor messaging system, ultra-wide band (UWB), and pedestrian dead reckoning (PDR), have been investigated. The development of these technologies allows tracking of movement of both people and/or goods in indoor spaces, people and/or goods behavior analysis is expected as one of the key technologies for operation optimization. However, when we use these technologies for human tracking, there are some problem as follows. 1) Many cases need to use dedicated facilities (e.g. UWB). 2) When we use smartphone as sensing device, battery depletion is one of the big problem (especially using PDR). 3) the accuracy is instability for tracking (e.g. Wi-Fi). Based on these matters, in this study we designed and developed an indoor positioning system using BLE positioning. And, we adopted smartphone for business use as sensing device, developed a smartphone application runs on android OS. Moreover, we conducted the field test of developed system at Itoki Corporation's ITOKI Tokyo Innovation Center, SYNQA, office (Tokyo, Japan). Over 40 workers participated in this field test, and worker tracking log data were collected for 6 weeks. We analyzed the characteristics of the workers' behavior using this log data as a prototyping.

Design and analysis of a flux intensifying permanent magnet embedded salient pole wind generator

NASA Astrophysics Data System (ADS)

Guo, Yujing; Jin, Ping; Lin, Heyun; Yang, Hui; Lyu, Shukang

2018-05-01

This paper presents an improved flux intensifying permanent magnet embedded salient pole wind generator (FI-PMESPWG) with mirror symmetrical magnetizing directions permanent magnet (PM) for improving generator's performances. The air-gap flux densities, the output voltage, the cogging torque and the d- and q-axis inductances of FI-PMESPWG are all calculated and analyzed by using the finite element method (FEM). To highlight the advantages of the proposed FI-PMESPWG, an original permanent magnet embedded salient pole wind generator (PMESPWG) model is adopted for comparison under the same operating conditions. The calculating results show that the air-gap flux densities of FI-PMESPWG are intensified with the same magnet amounts because the PMs are set in a form of V shape in each pole. The difference between d-axis inductance and q-axis inductance of the proposed FI-PMESPWG is reduced. Thus, the output power of the proposed FI-PMESPWG reaches a higher value than that of the original PMESPWG at the same current phase angle. The cogging torque is diminished because the flux path is changed. All the analysis results indicate that the electromagnetic characteristics of the proposed FI-PMESPWG are significantly better than that of the original PMESPWG.

Influence of feedstock-to-inoculum ratio on performance and microbial community succession during solid-state thermophilic anaerobic co-digestion of pig urine and rice straw.

PubMed

Meng, Lingyu; Xie, Li; Kinh, Co Thi; Suenaga, Toshikazu; Hori, Tomoyuki; Riya, Shohei; Terada, Akihiko; Hosomi, Masaaki

2018-03-01

This study investigated the effect of the feedstock-to-inoculum (F/I) ratio on performance of the solid-state anaerobic co-digestion of pig urine and rice straw inoculated with a solid digestate, and clarified the microbial community succession. A 44-day biochemical methane potential test at F/I ratios of 0.5, 1, 2 and 3 at 55 °C and a 35-day large-scale batch test at F/I ratios of 0.5 and 3 at 55 °C were conducted to investigate the effects of F/I ratio on anaerobic digestibility and analyze microbial community succession, respectively. The highest cumulative methane yield was 353.7 m 3 /t VS in the large-scale batch test. Volatile fatty acids did not accumulate at any F/I ratios. The volatile solids reduction rate was highest at a F/I ratio of 0.5. Microbial community structures were similar between F/I ratios of 3 and 0.5, despite differences in digestion performance, suggesting that stable operation can be achieved at these ratios. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Saccharomyces cerevisiae as a model organism for studying the carcinogenicity of non-ionizing electromagnetic fields and radiation].

PubMed

Voĭchuk, S I

2014-01-01

Medical and biological aspects of the effects of non-ionizing electromagnetic (EM) fields and radiation on human health are the important issues that have arisen as a result of anthropogenic impact on the biosphere. Safe use of man-made sources of non-ionizing electromagnetic fields and radiation in a broad range of frequencies--static, radio-frequency and microwave--is a subject of discussions and speculations. The main problem is the lack of understanding of the mechanism(s) of reception of EMFs by living organisms. In this review we have analyzed the existing literature data regarding the effects of the electromagnetic radiation on the model eukaryotic organism--yeast Saccharomyces cerevisiae. An attempt was made to estimate the probability of induction of carcinogenesis in humans under the influence of magnetic fields and electromagnetic radiation of extremely low frequency, radio frequency and microwave ranges.

Carrier-envelope-phase control of asymmetries in the multiphoton ionization of xenon atoms by ultrashort bichromatic fields

NASA Astrophysics Data System (ADS)

Kerbstadt, S.; Pengel, D.; Englert, L.; Bayer, T.; Wollenhaupt, M.

2018-06-01

We report on bichromatic multiphoton ionization of xenon atoms (Xe) to demonstrate carrier-envelope-phase (CEP) control of lateral asymmetries in the photoelectron momentum distribution. In the experiments, we employ a 4 f polarization pulse shaper to sculpture bichromatic fields with commensurable center frequencies ω1:ω2=7 :8 from an over-octave-spanning CEP-stable white light supercontinuum by spectral amplitude and phase modulation. The bichromatic fields are spectrally tailored to induce controlled interferences of 7- vs 8-photon quantum pathways in the 5 P3 /2 ionization continuum of Xe. The CEP sensitivity of the asymmetric final-state wave function arises from coherent superposition of continuum states with opposite parity. Our results demonstrate that shaper-generated bichromatic fields with tailored center frequency ratio are a suitable tool to localize CEP-sensitive asymmetries in a specific photoelectron kinetic-energy window.

Ionospheric modification using relativistic electron beams

NASA Technical Reports Server (NTRS)

Banks, Peter M.; Fraser-Smith, Anthony C.; Gilchrist, B. E.

1990-01-01

The recent development of comparatively small electron linear accelerators (linacs) now makes possible a new class of ionospheric modification experiments using beams of relativistic electrons. These experiments can potentially provide much new information about the interactions of natural relativistic electrons with other particles in the upper atmosphere, and it may also make possible new forms of ionization structures extending down from the lower ionosphere into the largely un-ionized upper atmosphere. The consequences of firing a pulsed 1 A, 5 Mev electron beam downwards into the upper atmosphere are investigated. If a small pitch angle with respect to the ambient geomagnetic field is selected, the beam produces a narrow column of substantial ionization extending down from the source altitude to altitudes of approximately 40 to 45 km. This column is immediately polarized by the natural middle atmosphere fair weather electric field and an increasingly large potential difference is established between the column and the surrounding atmosphere. In the regions between 40 to 60 km, this potential can amount to many tens of kilovolts and the associated electric field can be greater than the field required for breakdown and discharge. Under these conditions, it may be possible to initiate lightning discharges along the initial ionization channel. Filamentation may also occur at the lower end to drive further currents in the partially ionized gases of the stratosphere. Such discharges would derive their energy from the earth-ionosphere electrical system and would be sustained until plasma depletion and/or electric field reduction brought the discharge under control. It is likely that this artificially-triggered lightning would produce measurable low-frequency radiation.

[Uncertainty of cross calibration-applied beam quality conversion factor for the Japan Society of Medical Physics 12].

PubMed

Kinoshita, Naoki; Kita, Akinobu; Takemura, Akihiro; Nishimoto, Yasuhiro; Adachi, Toshiki

2014-09-01

The uncertainty of the beam quality conversion factor (k(Q,Q0)) of standard dosimetry of absorbed dose to water in external beam radiotherapy 12 (JSMP12) is determined by combining the uncertainty of each beam quality conversion factor calculated for each type of ionization chamber. However, there is no guarantee that ionization chambers of the same type have the same structure and thickness, so there may be individual variations. We evaluated the uncertainty of k(Q,Q0) for JSMP12 using an ionization chamber dosimeter and linear accelerator without a specific device or technique in consideration of the individual variation of ionization chambers and in clinical radiation field. The cross calibration formula was modified and the beam quality conversion factor for the experimental values [(k(Q,Q0))field] determined using the modified formula. It's uncertainty was calculated to be 1.9%. The differences between (k(Q,Q0))field of experimental values and k(Q,Q0) for Japan Society of Medical Physics 12 (JSMP12) were 0.73% and 0.88% for 6- and 10-MV photon beams, respectively, remaining within ± 1.9%. This showed k(Q,Q0) for JSMP12 to be consistent with (k(Q,Q0))field of experimental values within the estimated uncertainty range. Although inter-individual differences may be generated, even when the same type of ionized chamber is used, k(Q,Q0) for JSMP12 appears to be consistent within the estimated uncertainty range of (k(Q,Q0)field.

Tuning the Composition and Nanostructure of Pt/Ir Films via Anodized Aluminum Oxide Templated Atomic Layer Deposition

DTIC Science & Technology

2010-01-01

12 ] to dictate fi lm morphology. Such templated deposition is typically con- ducted by either electrodeposition or elec- troless deposition, with...non-enzymatic glucose sensing. [ 34–36 ] In particular, the syn- thesis of such nanostructured fi lms is delineated with a focus on the precise...deposited using alternating exposures to trimethylaluminum and H 2 O to provide a uniform nucleation layer for Pt and Ir fi lms. Nanostructured Pt fi

Localization Grid for Accurate Positioning Onboard a Carrier

DTIC Science & Technology

2017-06-30

the fi r t I 00 reads. It is clear that the RSSI measurement varies significantly over the different reads. It hould also be noted that, fo r the...yield a complete characterization of RSSI with respect to di stance and tag direction. By fi tting equation ( l .5) to the experimental data for di...For each observation in tant t, we feed the ML estimates of the instantaneous reader position as a fi fi [ " T T ]T h " T measurement to the Kalman

Ionization, photoelectron dynamics and elastic scattering in relativistic, ultra-strong field

NASA Astrophysics Data System (ADS)

Luo, Sui

Ultrastrong laser-matter interaction has direct bearing to next generation technologies including plasma acceleration, laser fusion and attosecond X-ray generation. The commonly known physics in strong field becomes different as one progress to ultrastrong field. The works presented in this dissertation theoretically study the influence of relativistic effect and magnetic component of the laser field on the ionization, photoelectron dynamics and elastic scattering processes. The influence of magnetic component (B laser) of circularly polarized (CP) ultrastrong fields (up to3 x 1022 W/cm2) on atomic bound state dynamics is investigated. The Poincare plots are used to find the changes in trajectory energies are on the order of a few percent for intensities up to1 x 1022 W/cm2. It is found that at intensities where ionization approaches 50% for the bound state, the small changes from Blaser of the circular polarized light can actually result in a several-fold decrease in ionization probability. The force on the bound electron exerted by the Lorentz force from B laser is perpendicular to the rotating plane of the circular polarized light, and this nature makes those trajectories which are aligned away from the minimum in the potential barrier stabilized against tunneling ionization. Our results provide a classical understanding for ionization in ultrastrong fields and indicate that relativistic effects in ultrastrong field ionization may most easily be seen with CP fields. The photoelectron energy spectra from elastic rescattering in ultrastrong laser fields (up to 2x1019 W/cm2) is studied by using a relativistic adaption of a semi-classical three-step recollision model. The Hartree-Fock scattering potentials are used in calculating the elastic rescattering for both hydrogenlike and noble gas species. It is found that there is a reduction in elastic rescattering for intensities beyond 6 x 1016 W/cm2 when the laser Lorentz deflection of the photoelectron exceeds its wave-function spread. A relativistic rescattering enhancement occurs at 2 x 1018 W/cm2, commensurate with relativistic motion of a classical electron in a single field cycle. The good comparison between the results with available experiments suggests the theory approach is well suited to modeling scattering in the ultrastrong intensity regime. We investigate the elastic scattering process as it changes from strong to ultrastrong fields with the photoelectron angular distributions from Ne, Ar, and Xe. Noble gas species with Hartree-Fock scattering potentials show a reduction in elastic rescattering with the increasing energy of ultrastrong fields. It is found that as one increases the returning photoelectron energy, rescattering becomes the dominating mechanism behind the yield distribution as the emission angle for all the species extends from 0° to 90°. The relativistic effects and the magnetic field do not change the angular distribution until one is well into the Gamma r "1 regime where the Lorentz defection significantly reduces the yield. As we proceed to the highest energy, the angular emission range narrows as the mechanism changes over to backscattering into narrow angles along the electric field.

Phase Structure of Strong-Field Tunneling Wave Packets from Molecules.

PubMed

Liu, Ming-Ming; Li, Min; Wu, Chengyin; Gong, Qihuang; Staudte, André; Liu, Yunquan

2016-04-22

We study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo model to describe the laser-driven dynamics of photoelectron momentum distributions of molecules. Using our model, we reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N_{2} reported by M. Meckel et al. [Nat. Phys. 10, 594 (2014)]. In addition to modeling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both the initial transverse momentum distribution and the molecular internuclear distance. We further show that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. The phase structure of the photoelectron wave packet is a key ingredient for modeling strong-field molecular photoelectron holography, high-harmonic generation, and molecular orbital imaging.

The fragility of statistically significant findings from randomized trials in head and neck surgery.

PubMed

Noel, Christopher W; McMullen, Caitlin; Yao, Christopher; Monteiro, Eric; Goldstein, David P; Eskander, Antoine; de Almeida, John R

2018-04-23

The Fragility Index (FI) is a novel tool for evaluating the robustness of statistically significant findings in a randomized control trial (RCT). It measures the number of events upon which statistical significance depends. We sought to calculate the FI scores for RCTs in the head and neck cancer literature where surgery was a primary intervention. Potential articles were identified in PubMed (MEDLINE), Embase, and Cochrane without publication date restrictions. Two reviewers independently screened eligible RCTs reporting at least one dichotomous and statistically significant outcome. The data from each trial were extracted and the FI scores were calculated. Associations between trial characteristics and FI were determined. In total, 27 articles were identified. The median sample size was 67.5 (interquartile range [IQR] = 42-143) and the median number of events per trial was 8 (IQR = 2.25-18.25). The median FI score was 1 (IQR = 0-2.5), meaning that changing one patient from a nonevent to an event in the treatment arm would change the result to a statistically nonsignificant result, or P > .05. The FI score was less than the number of patients lost to follow-up in 71% of cases. The FI score was found to be moderately correlated with P value (ρ = -0.52, P = .007) and with journal impact factor (ρ = 0.49, P = .009) on univariable analysis. On multivariable analysis, only the P value was found to be a predictor of FI score (P = .001). Randomized trials in the head and neck cancer literature where surgery is a primary modality are relatively nonrobust statistically with low FI scores. Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

Coexistence of ZigBee-Based WBAN and WiFi for Health Telemonitoring Systems.

PubMed

Kim, Yena; Lee, SeungSeob; Lee, SuKyoung

2016-01-01

The development of telemonitoring via wireless body area networks (WBANs) is an evolving direction in personalized medicine and home-based mobile health. A WBAN consists of small, intelligent medical sensors which collect physiological parameters such as electrocardiogram, electroencephalography, and blood pressure. The recorded physiological signals are sent to a coordinator via wireless technologies, and are then transmitted to a healthcare monitoring center. One of the most widely used wireless technologies in WBANs is ZigBee because it is targeted at applications that require a low data rate and long battery life. However, ZigBee-based WBANs face severe interference problems in the presence of WiFi networks. This problem is caused by the fact that most ZigBee channels overlap with WiFi channels, severely affecting the ability of healthcare monitoring systems to guarantee reliable delivery of physiological signals. To solve this problem, we have developed an algorithm that controls the load in WiFi networks to guarantee the delay requirement for physiological signals, especially for emergency messages, in environments with coexistence of ZigBee-based WBAN and WiFi. Since WiFi applications generate traffic with different delay requirements, we focus only on WiFi traffic that does not have stringent timing requirements. In this paper, therefore, we propose an adaptive load control algorithm for ZigBee-based WBAN/WiFi coexistence environments, with the aim of guaranteeing that the delay experienced by ZigBee sensors does not exceed a maximally tolerable period of time. Simulation results show that our proposed algorithm guarantees the delay performance of ZigBee-based WBANs by mitigating the effects of WiFi interference in various scenarios.

Socio-economic characteristics, living conditions and diet quality are associated with food insecurity in France.

PubMed

Bocquier, Aurélie; Vieux, Florent; Lioret, Sandrine; Dubuisson, Carine; Caillavet, France; Darmon, Nicole

2015-11-01

To assess the prevalence of household food insecurity (FI) in France and to describe its associations with socio-economic factors, health behaviours, diet quality and cost (estimated using mean food prices). Cross-sectional nationally representative survey. FI was assessed using an adapted version of the US Department of Agriculture's Food Insufficiency Indicator; dietary intake was assessed using a 7 d open-ended food record; and individual demographic, socio-economic and behavioural variables were assessed using self-administered questionnaires and interviews. Individuals experiencing FI were compared with food-secure individuals, the latter being divided into four categories according to quartiles of their income per consumption unit (FS1 to FS4). Differences among categories were analysed using χ² tests, ANOVA and tests for trend. Individual and National Dietary Survey (INCA2), 2006-2007. Adults aged 18-79 years (n 2624). Individuals experiencing FI represented 12·2% of the population. They were on average younger, more frequently women and single parents with children compared with those in the other four categories. Their mean income per consumption unit was higher than that in the FS1 category, but they reported poorer material and housing conditions. The prevalence of smoking and the mean daily time spent watching television were also higher in the FI category. No significant difference among categories was found for energy intake, but mean intakes of fruits, vegetables and fish were lower, and diet quality was slightly but significantly poorer in the FI category. Daily diet cost was also lower in the FI category. France is not spared by FI. FI should be routinely monitored at the national level and research should be promoted to identify effective strategies to reduce nutrition inequalities in France.

Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis

PubMed Central

Wang, Xiaogang; Jia, Yali; Spain, Rebecca; Potsaid, Benjamin; Liu, Jonathan J; Baumann, Bernhard; Hornegger, Joachim; Fujimoto, James G; Wu, Qiang; Huang, David

2015-01-01

Aims To investigate swept-source optical coherence tomography (OCT) angiography in the optic nerve head (ONH) and parafoveal regions in patients with multiple sclerosis (MS). Methods Fifty-two MS eyes and 21 healthy control (HC) eyes were included. There were two MS subgroups: 38 MS eyes without an optic neuritis (ON) history (MS −ON), and 14 MS eyes with an ON history (MS +ON). The OCT images were captured by high-speed 1050 nm swept-source OCT. The ONH flow index (FI) and parafoveal FI were quantified from OCT angiograms. Results The mean ONH FI was 0.160±0.010 for the HC group, 0.156±0.017 for the MS−ON group, and 0.140±0.020 for the MS+ON group. The ONH FI of the MS+ON group was reduced by 12.5% compared to HC eyes (p=0.004). A higher percentage of MS+ON eyes had abnormal ONH FI compared to HC patients (43% vs 5%, p=0.01). Mean parafoveal FIs were 0.126±0.007, 0.127±0.010, and 0.129±0.005 for the HC, MS−ON, and MS +ON groups, respectively, and did not differ significantly among them. The coefficient of variation (CV) of intravisit repeatability and intervisit reproducibility were 1.03% and 4.53% for ONH FI, and 1.65% and 3.55% for parafoveal FI. Conclusions Based on OCT angiography, the FI measurement is feasible, highly repeatable and reproducible, and it is suitable for clinical measurement of ONH and parafoveal perfusion. The ONH FI may be useful in detecting damage from ON and quantifying its severity. PMID:24831719

Mortality in Relation to Frailty in Patients Admitted to a Specialized Geriatric Intensive Care Unit

PubMed Central

Zeng, An; Song, Xiaowei; Dong, Jiahui; Mitnitski, Arnold; Liu, Jian; Guo, Zhenhui; Rockwood, Kenneth

2015-01-01

Background. In older adults admitted to intensive care units (ICUs), frailty influences prognosis. We examined the relationship between the frailty index (FI) based on deficit accumulation and early and late survival. Methods. Older patients (≥65 years) admitted to a specialized geriatric ICU at the Liuhuaqiao Hospital, Guangzhou, China between July–December 2011 (n = 155; age 82.7±7.1 y; 87.1% men) were followed for 300 days. The FI was calculated as the proportion present of 52 health deficits. FI performance was compared with that of several prognostic scores. Results. The 90-day death rate was 38.7% (n = 60; 27 died within 30 days). The FI score was correlated with the Glasgow Coma Scale, Karnofsky Scale, Palliative Performance Scale, Acute Physiology Score—APACHE II and APACHE IV (r 2 = 0.52 to 0.72, p < 0.001). Patients who died within 30 days had higher mean FI scores (0.41±0.11) than those who survived to 300 days (0.22±0.11; F = 38.91, p < 0.001). Each 1% increase in the FI from the previous level was associated with an 11% increase in the 30-day mortality risk (95% CI: 7%–15%) adjusting for age, sex, and the prognostic scores. The FI discriminated patients who died in 30 days from those who survived with moderately high accuracy (AUC = 0.89±0.03). No one with an FI score >0.46 survived past 90 days. Conclusion. ICU survival was strongly associated with the level of frailty at admission. An FI based on health deficit accumulation may help improve critical care outcome prediction in older adults. PMID:26400736

Hepatoprotective effects of Flagellaria indica are mediated through the suppression of pro-inflammatory cytokines and oxidative stress markers in rats.

PubMed

Gnanaraj, Charles; Shah, Muhammad Dawood; Makki, Jaafar Sadeq; Iqbal, Mohammad

2016-08-01

Context The antioxidative properties of plants or plant derivative products are well known for their free radical scavenging effects. Flagellaria indica L. (Flagellariaceae) (FI) is a tropical medicinal plant used by the natives of Sabah as medication for semi-paralysis. Objective This study evaluates the hepatoprotective mechanism of FI against carbon tetrachloride (CCl4)-mediated liver damage. Materials and methods Aqueous extract of FI leaves was orally administered to adult Sprague-Dawley rats once daily for 14 consecutive days at 300, 400, and 500 mg/kg b.w. prior to CCl4 treatment (1.0 mL/kg b.w.) on the 13th and 14th days. Results Total phenolic content in the aqueous extract of FI leaves was 65.88 ± 1.84 mg gallic acid equivalent/g. IC50 value for free radical scavenging activity of FI aqueous extract was reached at the concentration of 400 μg/mL. Biochemical studies show that the aqueous extract of FI was able to prevent the increase in levels of serum transaminases, alanine aminotransferase, and aspartate aminotransferase (38-74% recovery), and malondialdehyde formation (25-87% recovery) in a dose-dependent manner. Immunohistochemical results evidenced the suppression of oxidative stress markers (4-hydroxynonenal and 8-hydroxydeoxyguanosine) and pro-inflammatory markers (tumour necrosis factor-α, interleukin-6, prostaglandin E2). Histopathological and hepatocyte ultrastructural alterations proved that there were protective effects in FI against CCl4-mediated liver injury. Signs of toxicity were not present in rats treated with FI alone (500 mg/kg b.w.). Discussion and conclusion It can be concluded that the presence of phenolic constituents and their antioxidative effects can be credited to the hepatoprotective activity of FI.

FiO2 delivered by a turbine portable ventilator with an oxygen concentrator in an Austere environment.

PubMed

Bordes, Julien; Erwan d'Aranda; Savoie, Pierre-Henry; Montcriol, Ambroise; Goutorbe, Philippe; Kaiser, Eric

2014-09-01

Management of critically ill patients in austere environments is a logistic challenge. Availability of oxygen cylinders for the mechanically ventilated patient may be difficult in such a context. A solution is to use a ventilator able to function with an oxygen concentrator. We tested the SeQual Integra™ (SeQual, San Diego, CA) 10-OM oxygen concentrator paired with the Pulmonetic System(®) LTV 1000 ventilator (Pulmonetic Systems, Minneapolis, MN) and evaluated the delivered fraction of inspired oxygen (FiO2) across a range of minute volumes and combinations of ventilator settings. Two LTV 1000 ventilators were tested. The ventilators were attached to a test lung and FiO2 was measured by a gas analyzer. Continuous-flow oxygen was generated by the OC from 0.5 L/min to 10 L/min and injected into the oxygen inlet port of the LTV 1000. Several combinations of ventilator settings were evaluated to determine the factors affecting the delivered FiO2. The LTV 1000 ventilator is a turbine ventilator that is able to deliver high FiO2 when functioning with an oxygen concentrator. However, modifications of the ventilator settings such as increase in minute ventilation affect delivered FiO2 even if oxygen flow is constant on the oxygen concentrator. The ability of an oxygen concentrator to deliver high FiO2 when used with a turbine ventilator makes this method of oxygen delivery a viable alternative to cylinders in austere environments when used with a turbine ventilator. However, FiO2 has to be monitored continuously because delivered FiO2 decreases when minute ventilation is increased. Copyright © 2014 Elsevier Inc. All rights reserved.

Frailty Change and Major Osteoporotic Fracture in the Elderly: Data from the Global Longitudinal Study of Osteoporosis in Women 3-Year Hamilton Cohort.

PubMed

Li, Guowei; Papaioannou, Alexandra; Thabane, Lehana; Cheng, Ji; Adachi, Jonathan D

2016-04-01

Investigating the cumulative rate of deficits and the change of a frailty index (FI) chronologically is helpful in clinical and research settings in the elderly. However, limited evidence for the change of frailty before and after some nonfatal adverse health event such as a major osteoporotic fracture (MOF) is available. Data from the Global Longitudinal Study of Osteoporosis in Women 3-Year Hamilton cohort were used in this study. The changes of FI before and after onset of MOF were compared between the women with and without incident MOF. We also evaluated the relationship between risk of MOF, falls, and death and the change of FI and the absolute FI measures. There were 3985 women included in this study (mean age 69.4 years). The change of FI was significantly larger in the women with MOF than those without MOF at year 1 (0.085 versus 0.067, p = 0.036) and year 2 (0.080 versus 0.052, p = 0.042) post-baseline. The FI change was not significantly related with risk of MOF independently of age. However, the absolute FI measures were significantly associated with increased risk of MOF, falls, and death independently of age. In summary, the increase of the FI is significantly larger in the elderly women experiencing a MOF than their peer controls, indicating their worsening frailty and greater deficit accumulation after a MOF. Measures of the FI change may aid in the understanding of cumulative aging nature in the elderly and serve as an instrument for intervention planning and assessment. © 2015 American Society for Bone and Mineral Research.

Frailty Change and Major Osteoporotic Fracture in the Elderly: Data from the Global Longitudinal Study of Osteoporosis in Women 3-Year Hamilton Cohort

PubMed Central

Li, Guowei; Papaioannou, Alexandra; Thabane, Lehana; Cheng, Ji; Adachi, Jonathan D

2016-01-01

Investigating the cumulative rate of deficits and the change of a frailty index (FI) chronologically is helpful in clinical and research settings in the elderly. However, limited evidence for the change of frailty before and after some nonfatal adverse health event such as a major osteoporotic fracture (MOF) is available. Data from the Global Longitudinal Study of Osteoporosis in Women 3-Year Hamilton cohort were used in this study. The changes of FI before and after onset of MOF were compared between the women with and without incident MOF. We also evaluated the relationship between risk of MOF, falls, and death and the change of FI and the absolute FI measures. There were 3985 women included in this study (mean age 69.4 years). The change of FI was significantly larger in the women with MOF than those without MOF at year 1 (0.085 versus 0.067, p = 0.036) and year 2 (0.080 versus 0.052, p = 0.042) post-baseline. The FI change was not significantly related with risk of MOF independently of age. However, the absolute FI measures were significantly associated with increased risk of MOF, falls, and death independently of age. In summary, the increase of the FI is significantly larger in the elderly women experiencing a MOF than their peer controls, indicating their worsening frailty and greater deficit accumulation after a MOF. Measures of the FI change may aid in the understanding of cumulative aging nature in the elderly and serve as an instrument for intervention planning and assessment. PMID:26547825

Terahertz field-induced ionization and perturbed free induction decay of excitons in bulk GaAs

NASA Astrophysics Data System (ADS)

Murotani, Yuta; Takayama, Masayuki; Sekiguchi, Fumiya; Kim, Changsu; Akiyama, Hidefumi; Shimano, Ryo

2018-03-01

We investigated the interaction between an intense terahertz (THz) pulse and excitons in bulk GaAs by using THz pump near-infrared (NIR) optical probe spectroscopy. We observed a clear spectral oscillation in the NIR transient absorption spectra at low temperature, which is interpreted as the THz pump-induced perturbed free induction decay (PFID) of the excitonic interband polarization. We performed a numerical simulation based on a microscopic theory and identified that the observed PFID signal originates from the THz field-induced ionization of excitons. Using a real-space representation of the excitonic wave function, we visualized how the ionization of an exciton proceeds under the intense single-cycle THz electric field. We also calculated the nonlinear susceptibility with the lowest-order perturbation theory assuming a weak THz pump, which showed a similar spectral feature with that obtained by the full treatment to field-induced ionization process. This coincidence is attributed to the fact that 1s-excitonic interband polarization is modified predominantly through interactions with the p-wave component of the excitonic wave function. A simple phenomenological expression of the PFID signal is presented to discuss effects of the THz pump pulse duration on the spectral oscillation.

Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones.

PubMed

Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

2015-07-20

This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications.

Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones

PubMed Central

Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

2015-01-01

This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications. PMID:26205269

The influence of bremsstrahlung on electric discharge streamers in N2, O2 gas mixtures

NASA Astrophysics Data System (ADS)

Köhn, C.; Chanrion, O.; Neubert, T.

2017-01-01

Streamers are ionization filaments of electric gas discharges. Negative polarity streamers propagate primarily through electron impact ionization, whereas positive streamers in air develop through ionization of oxygen by UV photons emitted by excited nitrogen; however, experiments show that positive streamers may develop even for low oxygen concentrations. Here we explore if bremsstrahlung ionization facilitates positive streamer propagation. To discriminate between effects of UV and bremsstrahlung ionization, we simulate the formation of a double headed streamer at three different oxygen concentrations: no oxygen, 1 ppm O2 and 20% O2, as in air. At these oxygen levels, UV-relative to bremsstrahlung ionization is zero, small, and large. The simulations are conducted with a particle-in-cell code in a cylindrically symmetric configuration at ambient electric field magnitudes three times the conventional breakdown field. We find that bremsstrahlung induced ionization in air, contrary to expectations, reduces the propagation velocity of both positive and negative streamers by about 15%. At low oxygen levels, positive streamers stall; however, bremsstrahlung creates branching sub-streamers emerging from the streamer front that allow propagation of the streamer. Negative streamers propagate more readily forming branching sub-streamers. These results are in agreement with experiments. At both polarities, ionization patches are created ahead of the streamer front. Electrons with the highest energies are in the sub-streamer tips and the patches.

2017 Valparaíso earthquake sequence and the megathrust patchwork of central Chile

NASA Astrophysics Data System (ADS)

Nealy, Jennifer L.; Herman, Matthew W.; Moore, Ginevra L.; Hayes, Gavin P.; Benz, Harley M.; Bergman, Eric A.; Barrientos, Sergio E.

2017-09-01

In April 2017, a sequence of earthquakes offshore Valparaíso, Chile, raised concerns of a potential megathrust earthquake in the near future. The largest event in the 2017 sequence was a M6.9 on 24 April, seemingly colocated with the last great-sized earthquake in the region—a M8.0 in March 1985. The history of large earthquakes in this region shows significant variation in rupture size and extent, typically highlighted by a juxtaposition of large ruptures interspersed with smaller magnitude sequences. We show that the 2017 sequence ruptured an area between the two main slip patches during the 1985 earthquake, rerupturing a patch that had previously slipped during the October 1973 M6.5 earthquake sequence. A significant gap in historic ruptures exists directly to the south of the 2017 sequence, with large enough moment deficit to host a great-sized earthquake in the near future, if it is locked.

Advanced Integration of WiFi and Inertial Navigation Systems for Indoor Mobile Positioning

NASA Astrophysics Data System (ADS)

Evennou, Frédéric; Marx, François

2006-12-01

This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS) are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

Clinical interpretation of the Spinal Cord Injury Functional Index (SCI-FI)

PubMed Central

Fyffe, Denise; Kalpakjian, Claire Z.; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Kirshblum, Steven C.; Tulsky, David S.; Jette, Alan M.

2016-01-01

Objective: To provide validation of functional ability levels for the Spinal Cord Injury – Functional Index (SCI-FI). Design: Cross-sectional. Setting: Inpatient rehabilitation hospital and community settings. Participants: A sample of 855 individuals with traumatic spinal cord injury enrolled in 6 rehabilitation centers participating in the National Spinal Cord Injury Model Systems Network. Interventions: Not Applicable. Main Outcome Measures: Spinal Cord Injury-Functional Index (SCI-FI). Results: Cluster analyses identified three distinct groups that represent low, mid-range and high SCI-FI functional ability levels. Comparison of clusters on personal and other injury characteristics suggested some significant differences between groups. Conclusions: These results strongly support the use of SCI-FI functional ability levels to document the perceived functional abilities of persons with SCI. Results of the cluster analysis suggest that the SCI-FI functional ability levels capture function by injury characteristics. Clinical implications regarding tracking functional activity trajectories during follow-up visits are discussed. PMID:26781769

Alcohol Use and Food Insecurity among People Living with HIV in Mbarara, Uganda and St. Petersburg, Russia

PubMed Central

Patts, Gregory J.; Cheng, Debbie M.; Emenyonu, Nneka; Bridden, Carly; Gnatienko, Natalia; Lloyd-Travaglini, Christine A.; Ngabirano, Christine; Yaroslavtseva, Tatiana; Muyindike, Winnie R.; Weiser, Sheri D.; Krupitsky, Evgeny M.; Hahn, Judith A.; Samet, Jeffrey H.

2016-01-01

Food insecurity (FI) is a documented problem associated with adverse health outcomes among HIV-infected populations. Little is known about the relationship between alcohol use and FI. We assessed whether heavy alcohol use was associated with FI among HIV-infected, antiretroviral therapy (ART)-naïve cohorts in Uganda and Russia. Inverse probability of treatment weighted logistic regression models were used to evaluate the association using cross-sectional baseline data. FI was experienced by half of the Russia cohort (52%) and by a large majority of the Uganda cohort (84%). We did not detect an association between heavy alcohol use and FI in either cohort (Russia: AOR = 0.80, 95% CI = 0.46, 1.40; Uganda: AOR = 1.00, 95% CI = 0.57, 1.74) or based on the overall combined estimate (AOR = 0.89, 95% CI = 0.60, 1.33). Future studies should explore the determinants of FI in HIV-infected populations to inform strategies for its mitigation. PMID:27699595

Accumulation in coastal West Antarctic ice core records and the role of cyclone activity

NASA Astrophysics Data System (ADS)

Hosking, J. Scott; Fogt, Ryan; Thomas, Elizabeth R.; Moosavi, Vahid; Phillips, Tony; Coggins, Jack; Reusch, David

2017-09-01

Cyclones are an important component of Antarctic climate variability, yet quantifying their impact on the polar environment is challenging. We assess how cyclones which pass through the Bellingshausen Sea affect accumulation over Ellsworth Land, West Antarctica, where we have two ice core records. We use self-organizing maps (SOMs), an unsupervised machine learning technique, to group cyclones into nine SOM nodes differing by their trajectories (1980-2015). The annual frequency of cyclones associated with the first SOM node (SOM1, which generally originate from lower latitudes over the South Pacific Ocean) is significantly (p < 0.001) correlated with annual accumulation, with the highest seasonal correlations (p < 0.001) found during autumn. While significant (p < 0.01) increases in vertically integrated water vapor over the South Pacific Ocean coincide with this same group of cyclones, we find no indication that this has led to an increase in moisture advection into, nor accumulation over, Ellsworth Land over this short time period.

Wi-Fi and health: review of current status of research.

PubMed

Foster, Kenneth R; Moulder, John E

2013-12-01

This review summarizes the current state of research on possible health effects of Wi-Fi (a commercial name for IEEE 802.11-compliant wireless networking). In response to public concerns about health effects of Wi-Fi and wireless networks and calls by government agencies for research on possible health and safety issues with the technology, a considerable amount of technology-specific research has been completed. A series of high quality engineering studies have provided a good, but not complete, understanding of the levels of radiofrequency (RF) exposure to individuals from Wi-Fi. The limited number of technology-specific bioeffects studies done to date are very mixed in terms of quality and outcome. Unequivocally, the RF exposures from Wi-Fi and wireless networks are far below U.S. and international exposure limits for RF energy. While several studies report biological effects due to Wi-Fi-type exposures, technical limitations prevent drawing conclusions from them about possible health risks of the technology. The review concludes with suggestions for future research on the topic.

Frailty prevalence and factors associated with the Frailty Phenotype and Frailty Index: Findings from the North West Adelaide Health Study.

PubMed

Thompson, Mark Q; Theou, Olga; Yu, Solomon; Adams, Robert J; Tucker, Graeme R; Visvanathan, Renuka

2018-06-01

To determine the prevalence of frailty and associated factors in the North West Adelaide Health Study (2004-2006) using the Frailty Phenotype (FP) and Frailty Index (FI). Frailty was measured in 909 community-dwelling participants aged ≥65 years using the FP and FI. The FP classified 18% of participants as frail and the FI 48%. The measures were strongly correlated (r = 0.76, P < 0.001) and had a kappa agreement of 0.38 for frailty classification, with 37% of participants classified as non-frail by the FP being classified as frail by the FI. Being older, a current smoker, and having multimorbidity and polypharmacy were associated with higher frailty levels by both tools. Female, low income, obesity and living alone were associated with the FI. Frailty prevalence was higher when assessed using the FI. Socioeconomic factors and other health determinants contribute to higher frailty levels. © 2017 AJA Inc.

Single and double multiphoton ionization of Li and Be atoms by strong laser fields

NASA Astrophysics Data System (ADS)

Telnov, Dmitry; Heslar, John; Chu, Shih-I.

2011-05-01

The time-dependent density functional theory with self-interaction correction and proper asymptotic long-range potential is extended for nonperturbative treatment of multiphoton single and double ionization of Li and Be atoms by strong 800 nm laser fields. We make use of the time-dependent Krieger-Li-Iafrate (TDKLI) exchange-correlation potential with the integer discontinuity which improves the description of the double ionization process. However, we have found that the discontinuity of the TDKLI potential is not sufficient to reproduce the characteristic feature of double ionization. This may happen because the discontinuity of the TDKLI potential is related to the spin particle numbers only and not to the total particle number. Introducing a discontinuity with respect to the total particle number to the exchange-correlation potential, we were able to obtain the knee structure in the intensity dependence of the double ionization probability of Be. This work was partially supported by DOE and NSF and by NSC-Taiwan.

Temporal correlation and correlated momentum distribution in nonsequential double ionization of Mg by circularly polarized laser fields

NASA Astrophysics Data System (ADS)

Xu, Tong-Tong; Ben, Shuai; Guo, Pei-Ying; Song, Kai-Li; Zhang, Jun; Liu, Xue-Shen

2017-07-01

We use the classical ensemble method to investigate the nonsequential double ionization (NSDI) process of Mg atoms in circularly polarized laser fields at a lower laser intensity. We illustrate the temporal correlation of the ‘side-by-side’ and the ‘back-to-back emission’. It indicates that the two electrons are more likely to be emitted at the same time for the ‘side-by-side emission’. We demonstrate the electronic trajectories from recollision-induced ionization (RII) and recollision-induced excitation with subsequent ionization (RESI). The distribution of the angle between the two ionized directions of the two electrons and the ion momentum distribution show that the anticorrelation distribution is dominant in the RESI mechanism and correlation distribution is dominant in the RII mechanism. The momentum distributions of Mg atoms for the slow and the fast electrons present a similar structure to the experimental observation of Ar atoms by Liu et al 2014 (Phys. Rev. Lett. 112 013003).

Strong-field ionization of xenon dimers: The effect of two-equivalent-center interference and of driving ionic transitions

NASA Astrophysics Data System (ADS)

Zhang, C.; Feng, T.; Raabe, N.; Rottke, H.

2018-02-01

Strong-field ionization (SFI) of the homonuclear noble gas dimer Xe2 is investigated and compared with SFI of the Xe atom and of the ArXe heteronuclear dimer by using ultrashort Ti:sapphire laser pulses and photoelectron momentum spectroscopy. The large separation of the two nuclei of the dimer allows the study of two-equivalent-center interference effects on the photoelectron momentum distribution. Comparing the experimental results with a new model calculation, which is based on the strong-field approximation, actually reveals the influence of interference. Moreover, the comparison indicates that the presence of closely spaced gerade and ungerade electronic state pairs of the Xe2 + ion at the Xe2 ionization threshold, which are strongly dipole coupled, affects the photoelectron momentum distribution.

Design and commissioning of a high magnetic field muon spin relaxation spectrometer at the ISIS pulsed neutron and muon source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lord, J. S.; McKenzie, I.; Baker, P. J.

2011-07-15

The high magnetic field (HiFi) muon instrument at the ISIS pulsed neutron and muon source is a state-of-the-art spectrometer designed to provide applied magnetic fields up to 5 T for muon studies of condensed matter and molecular systems. The spectrometer is optimised for time-differential muon spin relaxation studies at a pulsed muon source. We describe the challenges involved in its design and construction, detailing, in particular, the magnet and detector performance. Commissioning experiments have been conducted and the results are presented to demonstrate the scientific capabilities of the new instrument.

Design and Installation of a Field Ionization Test Chamber for Ion Thrusters

DTIC Science & Technology

2011-12-01

where F is thrust, m& is the mass flow rate of the propellant, and go is the standard acceleration due to gravity at sea level [1]. It provides a...only one graphene wall, and multi- walled CNT ( MWCNT ), which consist of multiple, concentric walls of graphene (Figure 9). One of the most unique...ionization chamber to ensure the mass flow rate going into the chamber matches the mass flow rate leaving it. 46 B. FIELD EMISSION AND FIELD

Effect of macronutrient composition on short-term food intake and weight loss.

PubMed

Bellissimo, Nick; Akhavan, Tina

2015-05-01

The purpose of this review is to describe the role of macronutrient composition on the suppression of short-term food intake (FI) and weight loss. The effects of macronutrient composition on short-term FI will be reviewed first, followed by a brief examination of longer-term clinical trials that vary in effects of dietary macronutrient composition on weight loss. The objectives were: 1) to examine the effect of macronutrient composition on the suppression of short-term FI, 2) to determine whether some macronutrient sources suppress FI beyond their provision of energy, 3) to assess the combined effects of macronutrients on FI and glycemic response, and 4) to determine whether knowledge of the effect of macronutrients on short-term FI has led to greater success in spontaneous weight loss, adherence to energy-restricted diets, and better weight maintenance after weight loss. Although knowledge of macronutrient composition on short-term FI regulation has advanced our understanding of the role of diet composition on energy balance, it has yet to lead to greater success in long-term weight loss and weight maintenance. It is clear from this review that many approaches based on manipulating dietary macronutrient composition can help people lose weight as long as they follow the diets. However, only by evaluating the interaction between the physiologic systems that govern FI and body weight may the benefits of dietary macronutrient composition be fully realized. © 2015 American Society for Nutrition.

Alum Adjuvant Enhances Protection against Respiratory Syncytial Virus but Exacerbates Pulmonary Inflammation by Modulating Multiple Innate and Adaptive Immune Cells

PubMed Central

Kim, Ki-Hye; Lee, Young-Tae; Hwang, Hye Suk; Kwon, Young-Man; Jung, Yu-Jin; Lee, Youri; Lee, Jong Seok; Lee, Yu-Na; Park, Soojin; Kang, Sang-Moo

2015-01-01

Respiratory syncytial virus (RSV) is well-known for inducing vaccine-enhanced respiratory disease after vaccination of young children with formalin-inactivated RSV (FI-RSV) in alum formulation. Here, we investigated alum adjuvant effects on protection and disease after FI-RSV immunization with or without alum in comparison with live RSV reinfections. Despite viral clearance, live RSV reinfections caused weight loss and substantial pulmonary inflammation probably due to high levels of RSV specific IFN-γ+IL4-, IFN-γ-TNF-α+, IFN-γ+TNF-α- effector CD4 and CD8 T cells. Alum adjuvant significantly improved protection as evidenced by effective viral clearance compared to unadjuvanted FI-RSV. However, in contrast to unadjuvanted FI-RSV, alum-adjuvanted FI-RSV (FI-RSV-A) induced severe vaccine-enhanced RSV disease including weight loss, eosinophilia, and lung histopathology. Alum adjuvant in the FI-RSV-A was found to be mainly responsible for inducing high levels of RSV-specific IFN-γ-IL4+, IFN-γ-TNF-α+ CD4+ T cells, and proinflammatory cytokines IL-6 and IL-4 as well as B220+ plasmacytoid and CD4+ dendritic cells, and inhibiting the induction of IFN-γ+CD8 T cells. This study suggests that alum adjuvant in FI-RSV vaccines increases immunogenicity and viral clearance but also induces atypical T helper CD4+ T cells and multiple inflammatory dendritic cell subsets responsible for vaccine-enhanced severe RSV disease. PMID:26468884

Does CT evidence of a flat inferior vena cava indicate hypovolemia in blunt trauma patients with solid organ injuries?

PubMed

Liao, Yu-Ying; Lin, Hung-Jung; Lu, Yu-Hui; Foo, Ning-Ping; Guo, How-Ran; Chen, Kuo-Tai

2011-06-01

Nonoperative management for selective patients with solid organ injuries from blunt trauma has gained wide acceptance. However, for trauma surgeons, it is often difficult to estimate a patient's circulatory volume. Some authors have proposed that the presence of a collapsed inferior vena cava (IVC) on computed tomography (CT) scan correlates with inadequate circulatory volume. Our aim was to verify whether CT evidence of a flat IVC (FI) is an indicator of hypovolemia in blunt trauma patients with solid organ injuries. We conducted a retrospective chart review of all blunt trauma patients with solid organ injuries admitted to our Medical Center from July 2003 to September 2006. Of the 226 patients reviewed, 29 had CT evidence of FI. We compared Injury Severity Scores, hemodynamic parameters, fluid and blood transfusion requirements, mortality rate, and hospital course between patients with (FI group) and without FI (non-FI [NFI] group). The FI group had higher rates of intensive care unit admission and mortality, in addition to longer intensive care unit stays, when compared with the NFI group. In addition, the patients in the FI group needed larger amounts of fluid and blood transfusions and presented lower hemoglobin levels during the first week of admission; furthermore, the majority deteriorated to a state of shock in the emergency department. CT evidence of FI is a good indicator of hypovolemia and an accurate predictor for prognosis in trauma patients with blunt solid organ injuries.

Lung ventilation strategies for acute respiratory distress syndrome: a systematic review and network meta-analysis

PubMed Central

Wang, Changsong; Wang, Xiaoyang; Chi, Chunjie; Guo, Libo; Guo, Lei; Zhao, Nana; Wang, Weiwei; Pi, Xin; Sun, Bo; Lian, Ailing; Shi, Jinghui; Li, Enyou

2016-01-01

To identify the best lung ventilation strategy for acute respiratory distress syndrome (ARDS), we performed a network meta-analysis. The Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, CINAHL, and the Web of Science were searched, and 36 eligible articles were included. Compared with higher tidal volumes with FiO2-guided lower positive end-expiratory pressure [PEEP], the hazard ratios (HRs) for mortality were 0.624 (95% confidence interval (CI) 0.419–0.98) for lower tidal volumes with FiO2-guided lower PEEP and prone positioning and 0.572 (0.34–0.968) for pressure-controlled ventilation with FiO2-guided lower PEEP. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning had the greatest potential to reduce mortality, and the possibility of receiving the first ranking was 61.6%. Permissive hypercapnia, recruitment maneuver, and low airway pressures were most likely to be the worst in terms of all-cause mortality. Compared with higher tidal volumes with FiO2-guided lower PEEP, pressure-controlled ventilation with FiO2-guided lower PEEP and lower tidal volumes with FiO2-guided lower PEEP and prone positioning ventilation are associated with lower mortality in ARDS patients. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning ventilation and lower tidal volumes with pressure-volume (P–V) static curve-guided individual PEEP are potential optimal strategies for ARDS patients. PMID:26955891

Results from Evaluation of Proposed ASME AG-1 Section FI Metal Media Filters - 13063

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, John A.; Giffin, Paxton K.; Parsons, Michael S.

High efficiency particulate air (HEPA) filtration technology is commonly used in Department of Energy (DOE) facilities that require control of radioactive particulate matter (PM) emissions due to treatment or management of radioactive materials. Although HEPA technology typically makes use of glass fiber media, metal and ceramic media filters are also capable of filtering efficiencies beyond the required 99.97%. Sintered metal fiber filters are good candidates for use in DOE facilities due to their resistance to corrosive environments and resilience at high temperature and elevated levels of relative humidity. Their strength can protect them from high differential pressure or pressure spikesmore » and allow for back pulse cleaning, extending filter lifetime. Use of these filters has the potential to reduce the cost of filtration in DOE facilities due to life cycle cost savings. ASME AG-1 section FI has not been approved due to a lack of protocols and performance criteria for qualifying section FI filters. The Institute for Clean Energy Technology (ICET) with the aid of the FI project team has developed a Section FI test stand and test plan capable of assisting in the qualification ASME AG-1 section FI filters. Testing done at ICET using the FI test stand evaluates resistance to rated air flow, test aerosol penetration and resistance to heated air of the section FI filters. Data collected during this testing consists of temperature, relative humidity, differential pressure, flow rate, upstream particle concentration, and downstream particle concentration. (authors)« less

Non-CO2 Greenhouse Gas Emissions in China 2012: Inventory and Supply Chain Analysis

NASA Astrophysics Data System (ADS)

Zhang, Bo; Zhang, Yaowen; Zhao, Xueli; Meng, Jing

2018-01-01

Reliable inventory information is critical in informing emission mitigation efforts. Using the latest officially released emission data, which is production based, we take a consumption perspective to estimate the non-CO2 greenhouse gas (GHG) emissions for China in 2012. The non-CO2 GHG emissions, which cover CH4, N2O, HFCs, PFCs, and SF6, amounted to 2003.0 Mt. CO2-eq (including 1871.9 Mt. CO2-eq from economic activities), much larger than the total CO2 emissions in some developed countries. Urban consumption (30.1%), capital formation (28.2%), and exports (20.6%) derived approximately four fifths of the total embodied emissions in final demand. Furthermore, the results from structural path analysis help identify critical embodied emission paths and key economic sectors in supply chains for mitigating non-CO2 GHG emissions in Chinese economic systems. The top 20 paths were responsible for half of the national total embodied emissions. Several industrial sectors such as Construction, Production and Supply of Electricity and Steam, Manufacture of Food and Tobacco and Manufacture of Chemicals, and Chemical Products played as the important transmission channels. Examining both production- and consumption-based non-CO2 GHG emissions will enrich our understanding of the influences of industrial positions, final consumption demands, and trades on national non-CO2 GHG emissions by considering the comprehensive abatement potentials in the supply chains.

The effect of Wi-Fi electromagnetic waves in unimodal and multimodal object recognition tasks in male rats.

PubMed

Hassanshahi, Amin; Shafeie, Seyed Ali; Fatemi, Iman; Hassanshahi, Elham; Allahtavakoli, Mohammad; Shabani, Mohammad; Roohbakhsh, Ali; Shamsizadeh, Ali

2017-06-01

Wireless internet (Wi-Fi) electromagnetic waves (2.45 GHz) have widespread usage almost everywhere, especially in our homes. Considering the recent reports about some hazardous effects of Wi-Fi signals on the nervous system, this study aimed to investigate the effect of 2.4 GHz Wi-Fi radiation on multisensory integration in rats. This experimental study was done on 80 male Wistar rats that were allocated into exposure and sham groups. Wi-Fi exposure to 2.4 GHz microwaves [in Service Set Identifier mode (23.6 dBm and 3% for power and duty cycle, respectively)] was done for 30 days (12 h/day). Cross-modal visual-tactile object recognition (CMOR) task was performed by four variations of spontaneous object recognition (SOR) test including standard SOR, tactile SOR, visual SOR, and CMOR tests. A discrimination ratio was calculated to assess the preference of animal to the novel object. The expression levels of M1 and GAT1 mRNA in the hippocampus were assessed by quantitative real-time RT-PCR. Results demonstrated that rats in Wi-Fi exposure groups could not discriminate significantly between the novel and familiar objects in any of the standard SOR, tactile SOR, visual SOR, and CMOR tests. The expression of M1 receptors increased following Wi-Fi exposure. In conclusion, results of this study showed that chronic exposure to Wi-Fi electromagnetic waves might impair both unimodal and cross-modal encoding of information.

The mechanism of detection of air pollution by an ionization chamber.

PubMed

Novković, D; Vukanac; Milosević, Z

2000-01-01

The mechanism of detection of chemical vapors in air by an ionization chamber supplied by DC and AC voltage has been described. The theoretical explanation is based on numerical solutions of the differential equations of the cylindrical ionization chamber. The current of the ionization chamber operating in the AC regime has two components: a conductive component, caused by the ions drifts, and a capacitive component, caused by the distortion of the electric field. The ionization chamber operating in the DC regime has only the first component; hence the AC supplied chamber has larger response than the DC supplied chamber.

Self-organization and self-limitation in high power impulse magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anders, Andre

The plasma over the racetrack in high power impulse magnetron sputtering develops in traveling ionization zones. Power densities can locally reach 10{sup 9} W/m{sup 2}, which is much higher than usually reported. Ionization zones move because ions are 'evacuated' by the electric field, exposing neutrals to magnetically confined, drifting electrons. Drifting secondary electrons amplify ionization of the same ionization zone where the primary ions came from, while sputtered and outgassing atoms are supplied to the following zone(s). Strong density gradients parallel to the target disrupt electron confinement: a negative feedback mechanism that stabilizes ionization runaway.

Structure factors for tunneling ionization rates of molecules: General Hartree-Fock-based integral representation

NASA Astrophysics Data System (ADS)

Madsen, Lars Bojer; Jensen, Frank; Dnestryan, Andrey I.; Tolstikhin, Oleg I.

2017-07-01

In the leading-order approximation of the weak-field asymptotic theory (WFAT), the dependence of the tunneling ionization rate of a molecule in an electric field on its orientation with respect to the field is determined by the structure factor of the ionizing molecular orbital. The WFAT yields an expression for the structure factor in terms of a local property of the orbital in the asymptotic region. However, in general quantum chemistry approaches molecular orbitals are expanded in a Gaussian basis which does not reproduce their asymptotic behavior correctly. This hinders the application of the WFAT to polyatomic molecules, which are attracting increasing interest in strong-field physics. Recently, an integral-equation approach to the WFAT for tunneling ionization of one electron from an arbitrary potential has been developed. The structure factor is expressed in an integral form as a matrix element involving the ionizing orbital. The integral is not sensitive to the asymptotic behavior of the orbital, which resolves the difficulty mentioned above. Here, we extend the integral representation for the structure factor to many-electron systems treated within the Hartree-Fock method and show how it can be implemented on the basis of standard quantum chemistry software packages. We validate the methodology by considering noble-gas atoms and the CO molecule, for which accurate structure factors exist in the literature. We also present benchmark results for CO2 and for NH3 in the pyramidal and planar geometries.

CRIT II electric, magnetic, and density measurements within an ionizing neutral stream

NASA Technical Reports Server (NTRS)

Swenson, C. M.; Kelley, M. C.; Primdahl, F.; Baker, K. D.

1990-01-01

Measurements from rocket-borne sensors inside a high-velocity neutral barium beam show a-factor-of-six increase in plasma density in a moving ionizing front. This region was colocated with intense fluctuating electric fields at frequencies well under the lower hybrid frequency for a barium plasma. Large quasi-dc electric and magnetic field fluctuations were also detected with a large component of the current and the electric field parallel to B(0). An Alfven wave with a finite electric field component parallel to the geomagnetic field was observed to propagate along B(0), where it was detected by an instrumented subpayload.

Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saheed, M. Shuaib M.; Muti Mohamed, Norani; Arif Burhanudin, Zainal, E-mail: zainabh@petronas.com.my

2014-03-24

Ionization gas sensors using vertically aligned multi-wall carbon nanotubes (MWCNT) are demonstrated. The sharp tips of the nanotubes generate large non-uniform electric fields at relatively low applied voltage. The enhancement of the electric field results in field emission of electrons that dominates the breakdown mechanism in gas sensor with gap spacing below 14 μm. More than 90% reduction in breakdown voltage is observed for sensors with MWCNT and 7 μm gap spacing. Transition of breakdown mechanism, dominated by avalanche electrons to field emission electrons, as decreasing gap spacing is also observed and discussed.

An Introduction to Atmospheric Radiation: Review for the Bulletin of AMS

NASA Technical Reports Server (NTRS)

Marshak, Alexander

2003-01-01

Whether you like a certain geophysical book or not, largely depends on your background. The field of radiative transfer and atmospheric radiation, in particular, combines people with a wide range of mathematical skills: from theoretical astrophysicists and nuclear physicists to meteorologists and ecologists. There is always a delicate balance between physical explanations and their mathematical interpretations. This balance is very personal and is based on your background. I came to the field of atmospheric radiative transfer as a mathematician with little knowledge of atmospheric physics. After being in the field for more than a decade, I still have gaps in my atmospheric science education. Thus I assess a radiative transfer book fi-om two main criteria: how well does it describe the material that is familiar to me (the radiative transfer equation and its numerical solutions) and how well does it help me to fill the gaps in my personal knowledge. So I present this review fi-om the perspective of a former mathematician working in the field of atmospheric radiation. . After being asked to review the book, my first intention was to compare the new edition with the previous one (Liou, 1980). In doing so, you can clearly follow the progress made in the field of atmospheric radiation over the past two decades. If there are few changes (as in Fundamental Radiative Transfer) or no changes at all (as in the Maxwell s equations), then the field has not seen much development. To the contrary, many differences between the two editions illustrate areas of major progress in the field, such as evidenced in Thermal Ineared Radiative Transfer and even in the creations of completely new fields like Three-Dimensional Radiative Transfer or Light Scattering by Nonspherical Particles. Obviously, the major changes happened not in the theory, which is at least half a century old, but in data quality and completely new measurements (mostly due to new satellite data) with higher accuracy and more reliability. The new edition illustrates this progress well.

Prenatal exposure to radiofrequencies: effects of WiFi signals on thymocyte development and peripheral T cell compartment in an animal model.

PubMed

Laudisi, Federica; Sambucci, Manolo; Nasta, Francesca; Pinto, Rosanna; Lodato, Rossella; Altavista, Pierluigi; Lovisolo, Giorgio Alfonso; Marino, Carmela; Pioli, Claudio

2012-12-01

Wireless local area networks are an increasing alternative to wired data networks in workplaces, homes, and public areas. Concerns about possible health effects of this type of signal, especially when exposure occurs early in life, have been raised. We examined the effects of prenatal (in utero) exposure to wireless fidelity (WiFi) signal-associated electromagnetic fields (2450 MHz center-frequency band) on T cell development and function. Pregnant mice were exposed whole body to a specific absorption rate of 4 W/kg, 2 h per day, starting 5 days after mating and ending 1 day before the expected delivery. Sham-exposed and cage control groups were used as controls. No effects on cell count, phenotype, and proliferation of thymocytes were observed. Also, spleen cell count, CD4/CD8 cell frequencies, T cell proliferation, and cytokine production were not affected by the exposure. These findings were consistently observed in the male and female offspring at early (5 weeks of age) and late (26 weeks of age) time points. Nevertheless, the expected differences associated with aging and/or gender were confirmed. In conclusion, our results do not support the hypothesis that the exposure to WiFi signals during prenatal life results in detrimental effects on the immune T cell compartment. Copyright © 2012 Wiley Periodicals, Inc.

The effects of light emitting diode therapy following high intensity exercise.

PubMed

Denis, Romain; O'Brien, Christopher; Delahunt, Eamonn

2013-05-01

To determine the effects of light emitting diode therapy (LEDT) irradiation on blood lactate concentration ([La]) clearance, peak power output and fatigue index (FI) following high intensity fatiguing exercise. Single-blinded randomised cross-over placebo controlled trial. University College Dublin, Institute for Sport and Health, Human performance laboratory. Eighteen healthy male athletes were recruited from field-based sports (including soccer, hockey and rugby union) and participated in the present study. Dependent variables were the peak power output elicited during the Wingate Anaerobic Test (WAnT), FI and [La] before and after each exercise. WAnT performance was measured prior to high intensity fatiguing exercise (Yo-Yo IR2), prior to LEDT or placebo, and following LEDT or placebo. [La] was measured at baseline, immediately after the Yo-Yo IR2, and in the 3rd, 9th, and 15th min following LEDT or placebo condition. No significant group by treatment interactions were observed for any outcome measures (P > 0.05). We conclude that LEDT irradiation applied following high intensity exercise was not effective and has no immediate effect on [La] clearance, peak power and FI, and thus has no significant effect on muscle recovery in athletes at the intensity and irradiation parameters used in the present study. Further research using different parameters is required to determine how LEDT may contribute to post-exercise recovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temperature dependence of electron impact ionization coefficient in bulk silicon

NASA Astrophysics Data System (ADS)

Ahmed, Mowfaq Jalil

2017-09-01

This work exhibits a modified procedure to compute the electron impact ionization coefficient of silicon for temperatures between 77 and 800K and electric fields ranging from 70 to 400 kV/cm. The ionization coefficients are computed from the electron momentum distribution function through solving the Boltzmann transport equation (BTE). The arrangement is acquired by joining Legendre polynomial extension with BTE. The resulting BTE is solved by differences-differential method using MATLAB®. Six (X) equivalent ellipsoidal and non-parabolic valleys of the conduction band of silicon are taken into account. Concerning the scattering mechanisms, the interval acoustic scattering, non-polar optical scattering and II scattering are taken into consideration. This investigation showed that the ionization coefficients decrease with increasing temperature. The overall results are in good agreement with previous experimental and theoretical reported data predominantly at high electric fields.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samedov, V. V., E-mail: v-samedov@yandex.ru

Fluctuations of charge induced by charge carriers on the detector electrodes make a significant contribution to the energy resolution of ionization detectors, namely, semiconductor detectors and gas and liquid ionization chambers. These fluctuations are determined by the capture of charge carriers, as they drift in the bulk of the detector under the action of an electric field, by traps. In this study, we give a correct mathematical description of charge induction on electrodes of an ionization detector for an arbitrary electric field distribution in the detector with consideration of charge carrier capture by traps. The characteristic function obtained in thismore » study yields the general expression for the distribution function of the charge induced on the detector electrodes. The formulas obtained in this study are useful for analysis of the influence of charge carrier transport on energy resolution of ionization detectors.« less