Thermoluminescence of NaCl:Cu Sintered Phosphors Exposed to Beta Irradiation

R. Bernal,C. Cruz-Vázquez,F. Brown,W. Tostado-García,R. Pérez-Salas,V.M. Castaño 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.4

NaCl:Cu pellet-shaped phosphors were synthesized through a sintering process. Some samples were exposed to beta irradiation in order to investigate their thermoluminescence properties and capabilities to be used in detecting and measuring ionizing radiation. The glow curves reveal at least four thermoluminescence peaks below 250°C, and a main one above 300°C when a 5°C/s heating rate is used. The lowest temperature peak vanishes in less than 3 min after irradiation, giving rise to an intense afterglow luminescence, potentially useful for in situ non-thermoluminescence dosimetry, and the next remains for about 3 h, but the high temperature one exhibits no important changes after that time. The thermoluminescence intensity increased as the radiation dose increased in the 0.417 - 25.0 Gy dose range. Because the position and the remarkable stability of the higher temperature peak, besides the strong afterglow produced by the fast decaying of the lower temperature peak, it is concluded that these phosphors are very suitable candidates to be used in both thermoluminescence and non thermoluminescence dosimetry of ionizing radiation, having advantages over monocrystals of similar composition. The synthesis route here followed can be reproduced in standard college laboratories, and thermoluminescence be measured in home-made systems, allowing design practices for interdisciplinary physics, chemistry electronics, and materials science students.

Quantum conductance fluctuations in semiconductor devices

B.C. Scannell,T.P. Martin,M.S. Fairbanks,H. Linke,C.A. Marlow,T.M. Fromhold,C.V. Brown,K. Ishibashi,R.P. Taylor 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

Magneto-conductance uctuations serve as the traditional method for investigating the dynamics of electrons as they ow throughsolid-state materials. Generated by electron wave interference, their spectral content is critically sensitive to the precise scattering con-gurations in the material. In this paper, we exploit this sensitivity to study the electron dynamics in the diusive regime of semiconduc-tors where the dynamics are determined by material-induced scattering. We show that the spectral content of the uctuations measuredon diusive n+GaAs wires and quasi-ballistic AlGaAs/GaAs wires follow a fractal scaling behaviour similar to that previously observed.

Cholinergic Neurons in the Basal Forebrain Promote Wakefulness by Actions on Neighboring Non-Cholinergic Neurons: An Opto-Dialysis Study

Zant, Janneke C.,Kim, Tae,Prokai, Laszlo,Szarka, Szabolcs,McNally, James,McKenna, James T.,Shukla, Charu,Yang, Chun,Kalinchuk, Anna V.,McCarley, Robert W.,Brown, Ritchie E.,Basheer, Radhika Society for Neuroscience 2016 The Journal of neuroscience Vol.36 No.6

<P>Understanding the control of sleep–wake states by the basal forebrain (BF) poses a challenge due to the intermingled presence of cholinergic, GABAergic, and glutamatergic neurons. All three BF neuronal subtypes project to the cortex and are implicated in cortical arousal and sleep–wake control. Thus, nonspecific stimulation or inhibition studies do not reveal the roles of these different neuronal types. Recent studies using optogenetics have shown that “selective” stimulation of BF cholinergic neurons increases transitions between NREM sleep and wakefulness, implicating cholinergic projections to cortex in wake promotion. However, the interpretation of these optogenetic experiments is complicated by interactions that may occur within the BF. For instance, a recent <I>in vitro</I> study from our group found that cholinergic neurons strongly excite neighboring GABAergic neurons, including the subset of cortically projecting neurons, which contain the calcium-binding protein, parvalbumin (PV) (Yang et al., 2014). Thus, the wake-promoting effect of “selective” optogenetic stimulation of BF cholinergic neurons could be mediated by local excitation of GABA/PV or other non-cholinergic BF neurons. In this study, using a newly designed opto-dialysis probe to couple selective optical stimulation with simultaneous <I>in vivo</I> microdialysis, we demonstrated that optical stimulation of cholinergic neurons locally increased acetylcholine levels and increased wakefulness in mice. Surprisingly, the enhanced wakefulness caused by cholinergic stimulation was abolished by simultaneous reverse microdialysis of cholinergic receptor antagonists into BF. Thus, our data suggest that the wake-promoting effect of cholinergic stimulation requires local release of acetylcholine in the basal forebrain and activation of cortically projecting, non-cholinergic neurons, including the GABAergic/PV neurons.</P><P><B>SIGNIFICANCE STATEMENT</B> Optogenetics is a revolutionary tool to assess the roles of particular groups of neurons in behavioral functions, such as control of sleep and wakefulness. However, the interpretation of optogenetic experiments requires knowledge of the effects of stimulation on local neurotransmitter levels and effects on neighboring neurons. Here, using a novel “opto-dialysis” probe to couple optogenetics and <I>in vivo</I> microdialysis, we report that optical stimulation of basal forebrain (BF) cholinergic neurons in mice increases local acetylcholine levels and wakefulness. Reverse microdialysis of cholinergic antagonists within BF prevents the wake-promoting effect. This important result challenges the prevailing dictum that BF cholinergic projections to cortex directly control wakefulness and illustrates the utility of “opto-dialysis” for dissecting the complex brain circuitry underlying behavior.</P>

Photometric redshifts for the Kilo-Degree Survey : Machine-learning analysis with artificial neural networks

Bilicki, M.,Hoekstra, H.,Brown, M. J. I.,Amaro, V.,Blake, C.,Cavuoti, S.,de Jong, J. T. A.,Georgiou, C.,Hildebrandt, H.,Wolf, C.,Amon, A.,Brescia, M.,Brough, S.,Costa-Duarte, M. V.,Erben, T.,Glazebroo EDP Sciences 2018 Astronomy and astrophysics Vol.616 No.-

<P>We present a machine-learning photometric redshift (ML photo-<I>z</I>) analysis of the Kilo-Degree Survey Data Release 3 (KiDS DR3), using two neural-network based techniques: ANNz2 and MLPQNA. Despite limited coverage of spectroscopic training sets, these ML codes provide photo-<I>z</I>s of quality comparable to, if not better than, those from the Bayesian Photometric Redshift (BPZ) code, at least up to <I>z</I>phot ≲ 0.9 and <I>r</I> ≲ 23.5. At the bright end of <I>r</I> ≲ 20, where very complete spectroscopic data overlapping with KiDS are available, the performance of the ML photo-<I>z</I>s clearly surpasses that of BPZ, currently the primary photo-<I>z</I> method for KiDS. Using the Galaxy And Mass Assembly (GAMA) spectroscopic survey as calibration, we furthermore study how photo-<I>z</I>s improve for bright sources when photometric parameters additional to magnitudes are included in the photo-<I>z</I> derivation, as well as when VIKING and WISE infrared (IR) bands are added. While the fiducial four-band <I>ugri</I> setup gives a photo-<I>z</I> bias 〈<I>δz</I>/(1 + <I>z</I>)〉 = −2 × 10<SUP>−4</SUP> and scatter <I>σδz/(1+z)</I> < 0.022 at mean 〈<I>z</I>〉 = 0.23, combining magnitudes, colours, and galaxy sizes reduces the scatter by ~7% and the bias by an order of magnitude. Once the <I>ugri</I> and IR magnitudes are joined into 12-band photometry spanning up to 12 <I>μ</I>m, the scatter decreases by more than 10% over the fiducial case. Finally, using the 12 bands together with optical colours and linear sizes gives 〈<I>δz</I>/(1 + <I>z</I>)〉 < 4 × 10<SUP>−5</SUP> and <I>σ</I><I>δz</I>/(1+<I>z</I>) < 0.019. This paper also serves as a reference for two public photo-<I>z</I> catalogues accompanying KiDS DR3, both obtained using the ANNz2 code. The first one, of general purpose, includes all the 39 million KiDS sources with four-band <I>ugri</I> measurements in DR3. The second dataset, optimised for low-redshift studies such as galaxy-galaxy lensing, is limited to <I>r</I> ≲ 20, and provides photo-<I>z</I>s of much better quality than in the full-depth case thanks to incorporating optical magnitudes, colours, and sizes in the GAMA-calibrated photo-<I>z</I> derivation.</P>

International key comparison CCQM-K94: 10 μmol/mol dimethyl sulfide in nitrogen

Lee, S,Heo, G S,Kim, Y,Oh, S,Han, Q,Wu, H,Konopelko, L A,Kustikov, Y A,Kolobova, A V,Efremova, O V,Pankratov, V V,Pavlov, M V,Culleton, L P,Brown, A S,Brookes, C,Li, J,Ziel, P R,van der Veen, A M H IOP 2016 Metrologia Vol.53 No.-

<P></P> <P>Dimethyl sulfide (DMS) is an important compound in monitoring climate change and is monitored by the World Meteorological Organization Global Atmospheric Watch Volatile Organic Compounds (WMO-GAW VOC) program at several monitoring sites. It is essential that measurement results are accurate and consistent among the assigned values for primary gas mixtures to meet the WMO requirement. The purpose of this comparison is to compare the measurement capability of DMS at approximately 10 μ­mol/mol and expectation to contribute the establishment of traceability to single measurement scale for DMS between NMIs.</P> <H2>Main text</H2> <P>To reach the main text of this paper, click on <A HREF='http://www.bipm.org/utils/common/pdf/final_reports/QM/K94/CCQM-K94_Final_Report.pdf'>Final Report</A>. Note that this text is that which appears in Appendix B of the BIPM key comparison database <A HREF='http://kcdb.bipm.org/'>kcdb.bipm.org/</A>.</P> <P>The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).</P>

High temperature operation and stability of phosphorescent OLEDs

V. I. Adamovich,M. S. Weaver,R. C. Kwong,J. J. Brown 한국물리학회 2005 Current Applied Physics Vol.5 No.1

Phosphorescent organic light emitting diodes were fabricated that show high eciencies with commercially viable lifetimes atdisplay brightnesses of tens of thousands of hours at room temperature. We investigate here the performance of theses devices atelevated temperatures. We demonstrate that devices containing phosphorescent dopants can be operated at temperatures up to 130.C. We also demonstrate improved device performance due to thermal treating e.g. a red phosphorescent device that decays by only10% in the rst 5500 h of operation driven with an initial luminance of 300 cd/m2

Biomechanical and Physiological Effects of Plyometric Training on Adolescent Cross-Country Runners

( Mark C. Lathrop ),( Eugene W. Brown ),( Chris J. Womack ),( V. Diarme Ulibarri ),( Chad Paton ),( Pete Osmond ) 한국스포츠정책과학원(구 한국스포츠개발원) 2001 International Journal of Applied Sports Sciences Vol.13 No.2

The purpose of this study was to compare the effectiveness of a traditional high school (14 to 18 years of age) cross-country training regimen typically used in the United States with a training program that includes plyometrics. The results of this study may be generalizable to similar training programs used by cross-country coaches of young athletes. Eighteen male and female cross-country runners were matched according to their previous running experience and randomly assigned to two groups. Participants followed a traditional cross-country training program for six weeks, except that two to three times a week the plyometrics group replaced some of their easy run training with 15-20 minutes of plyometric training. The participants were tested before and after the six-week training period. A treadmill test was used to determine running economy and VO2max. The participants were also evaluated by having them run across a force plate in order to determine support time, braking time, and braking change in velocity. Participants were also timed on a 3200-meter run in order to determine endurance performance. The dependent variables were each analyzed in a Group (PLYO vs. RUN) x Time (Pretest vs. Posttest) two-way mixed ANOVA. Participants in both groups significantly improved their running economy, (F (1, 14) = 44.47, P < .0001) and 3200-meter time, (F (1,14) = 8.13, p = .013), while braking change in velocity decreased significantly (F (1, 14) = 6.19, p = .026) from pretest to posttest. There was a trend of a Group x Time interaction effect for braking change in velocity (F(1, 14) = 3.31, p = .09) although it was not significant. The plyometric group decreased their braking change in velocity over the training period (although it was not significant), while there was no change in the running group. There were no significant differences between groups on any of the other dependent variables. These results suggest that replacing some run training with plyometrics for a short period of time in young cross-country runners does not enhance running performance or performance-related variables more than run-only training. However, the observed decrease in braking change in velocity may suggest biomechanical adaptations occur that could possibly impact performance if a long-term intervention is initiated.

Getting Down to the Bare Bones: Does laminoplasty or laminectomy With Fusion Provide Better Outcomes for Patients With Multilevel Cervical Spondylotic Myelopathy?

Nolan J. Brown,Brian V. Lien,Shane Shahrestani,Elliot H. Choi,Katelynn Tran,Sandra Gattas,Seth C. Ransom,Ali R. Tafreshi,Ryan Chase Ransom,Ronald Sahyouni,Alvin Chan,Michael Oh 대한척추신경외과학회 2021 Neurospine Vol.18 No.1

Objective: Cervical spondylotic myelopathy (CSM) is a degenerative disorder leading to progressive decline in spinal cord function. Cervical laminoplasty (CLP) and cervical laminectomy with fusion (CLF) are standard treatments for multilevel CSM. However, it is still unclear whether one procedure over the other provides better outcomes. Here, we performed a comprehensive review of published articles that compare the clinical outcomes and costs between CLP and CLF for CSM. Methods: A literature search was performed using PubMed, Web of Science, and Cochrane databases. Strict exclusion criteria were applied, and included articles were then assessed for publication year, study design, and significant differences in outcome variables. Results: From 519 studies identified with search terms, 38 studies were included for the qualitative analysis. Statistically significant differences in the clinical outcomes and costs were found in 18 studies. Eleven studies were prospective or retrospective, and 8 studies were meta-analyses. For the outcome variables of interest, results were reported by classifying into prospective studies, retrospective studies, and meta-analyses. Conclusion: CLP and CLF are 2 of the most commonly performed surgical procedures for the treatment of CSM. Although CLP and CLF each provide satisfactory clinical outcomes for patients with CMS, CLP may result in better cervical range of motion and less cost, length of stay, operation time, blood loss, paraspinal muscular atrophy, and rate of nerve palsies as compared to CLF. The major limitation of CLP versus CLF comparison studies includes the heterogeneity in techniques and preoperative criteria. Thus, further validation and investigations in larger cohorts will be required.

Sensitivity and discovery potential of the proposed nEXO experiment to neutrinoless double- β decay

Albert, J. B.,Anton, G.,Arnquist, I. J.,Badhrees, I.,Barbeau, P.,Beck, D.,Belov, V.,Bourque, F.,Brodsky, J. P.,Brown, E.,Brunner, T.,Burenkov, A.,Cao, G. F.,Cao, L.,Cen, W. R.,Chambers, C.,Charlebois, American Physical Society 2018 Physical Review C Vol.97 No.6

SUNSHINE, EARTHSHINE AND CLIMATE CHANGE: II. SOLAR ORIGINS OF VARIATIONS IN THE EARTH'S ALBEDO

GOODE P. R.,PALLE E.,YURCHYSHYN V.,QIU J.,HICKEY J.,RODRIGUEZ P. MONTANES,CHU M.-C.,KOLBE E.,BROWN C.T.,KOONIN S.E. The Korean Astronomical Society 2003 Journal of The Korean Astronomical Society Vol.36 No.suppl1

There are terrestrial signatures of the solar activity cycle in ice core data (Ram & Stoltz 1999), but the variations in the sun's irradiance over the cycle seem too small to account for the signature (Lean 1997; Goode & Dziembowski 2003). Thus, one would expect that the signature must arise from an indirect effect(s) of solar activity. Such an indirect effect would be expected to manifest itself in the earth's reflectance. Further, the earth's climate depends directly on the albedo. Continuous observations of the earthshine have been carried out from Big Bear Solar Observatory since December 1998, with some more sporadic measurements made during the years 1994 and 1995. We have determined the annual albedos both from our observations and from simulations utilizing the Earth Radiation Budget Experiment (ERBE) scene model and various datasets for the cloud cover, as well as snow and ice cover. With these, we look for inter-annual and longer-term changes in the earth's total reflectance, or Bond albedo. We find that both our observations and simulations indicate that the albedo was significantly higher during 1994-1995 (activity minimum) than for the more recent period covering 1999-2001 (activity maximum). However, the sizes of the changes seem somewhat discrepant. Possible indirect solar influences on the earth's Bond albedo are discussed to emphasize that our earthshine data are already sufficiently precise to detect, if they occur, any meaningful changes in the earth's reflectance. Still greater precision will occur as we expand our single site observations to a global network.