Analyzing Movements Development and Evaluation of the Body Awareness Scale Movement Quality (BAS MQ).

PubMed

Sundén, A; Ekdahl, C; Horstman, V; Gyllensten, A L

2016-06-01

Limitations in everyday movements, physical activities are/or pain are the main reasons for seeking help from a physiotherapist. The purpose of this study was to investigate the psychometric properties of the Body Awareness Scale Movement Quality (BAS MQ) focusing on factor structure, validity and reliability and to explore whether BAS MQ could discriminate between healthy individuals and patients. BAS MQ assesses both limitations and resources concerning functional ability and quality of movements. The total sample in the study (n = 172) consisted of individuals with hip osteoarthritis (OA) (n = 132), individuals with psychiatric disorders (n = 33) and healthy individuals (n = 7). A factor analysis of the BAS MQ was performed for the total group. Inter-rater reliability was tested in a group of individuals with hip OA (n = 24). Concurrent validity was tested in a group of individuals with hip OA (n = 89). The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), the 6-Minute Walk Test (6MWT) and the Hip Osteoarthritis Outcome Score (HOOS) were chosen in the validation process. The factor analysis revealed three factors that together explained 60.8% of the total variance of BAS MQ. The inter-rater reliability was considered good or very good with a kappa value of 0.61. Significant correlations between BAS MQ and SF-36, HOOS and 6MWT in the subjects with hip OA confirmed the validity. The BAS MQ was able to discriminate between healthy individuals and individuals with physical and psychiatric limitations. Results of the study revealed that BAS MQ has a satisfactory factor structure. The inter-rater reliability and validity were acceptable in a group of individuals with hip OA. BAS MQ could be a useful assessment tool for physiotherapists when evaluating the quality of everyday movements in different patient groups. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Methylquercetins stimulate melanin biosynthesis in a three-dimensional skin model.

PubMed

Yamauchi, Kosei; Mitsunaga, Tohru

2018-03-01

In a previous study, we found that both synthetic 3-O-methylquercetin (3MQ) and 3,4',7-O-trimethylquercetin (34'7TMQ) increased extracellular melanin content. 34'7TMQ increased the activity of melanogenic enzymes by stimulating the p38 pathway and the expression of microphthalmia-associated transcription factor (MITF). In contrast, 3MQ increased the activity of melanogenic enzymes without the involvement of MITF, which suggests that 3MQ inhibits the degradation of melanogenic enzymes. In the present study, we investigated the effects of 3MQ and 34'7TMQ on melanogenesis in normal human melanocytes and using a commercial three-dimensional (3D) skin model system. Both 3MQ and 34'7TMQ elongated the dendrites of normal human melanocytes from a Caucasian donor, but did not stimulate melanogenesis in the melanocytes. In the 3D skin model, which included melanocytes from an Asian donor, 3MQ and 34'7TMQ increased and elongated the melanocytes and showed a tendency to stimulate melanogenesis. These results suggest that 3MQ and 34'7TMQ could be put to practical use in skin care products and agents aimed at preventing hair graying.

Early body composition, but not body mass, is associated with future accelerated decline in muscle quality

PubMed Central

Chiles Shaffer, Nancy; Gonzalez‐Freire, Marta; Shardell, Michelle D.; Zoli, Marco; Studenski, Stephanie A.; Ferrucci, Luigi

2017-01-01

Abstract Background Muscle quality (MQ) or strength‐to‐mass ratio declines with aging, but the rate of MQ change with aging is highly heterogeneous across individuals. The identification of risk factors for accelerated MQ decline may offer clues to identity the underpinning physiological mechanisms and indicate targets for prevention and treatment. Using data from the Baltimore Longitudinal Study of Aging, we tested whether measures of body mass and body composition are associated with differential rates of changes in MQ with aging. Methods Participants included 511 men and women, aged 50 years or older, followed for an average of 4 years (range: 1–8). MQ was operationalized as ratio between knee‐extension isokinetic strength and CT‐thigh muscle cross‐sectional area. Predictors included body mass and body composition measures: weight (kg), body mass index (BMI, kg/m2), dual‐energy x‐ray absorptiometry‐measured total body fat mass (TFM, kg) and lean mass (TLM, kg), and body fatness (TFM/weight). Covariates were baseline age, sex, race, and body height. Results Muscle quality showed a significant linear decline over the time of the follow up (average rate of decline 0.02 Nm/cm2 per year, P < .001). Independent of covariates, neither baseline body weight (P = .756) nor BMI (P = .777) was predictive of longitudinal rate of decline in MQ. Instead, higher TFM and lower TLM at baseline predicted steeper longitudinal decline in MQ (P = .036 and P < .001, respectively). In particular, participants with both high TFM and low TLM at baseline experienced the most dramatic decline compared with those with low TFM and high TLM (about 3% per year vs. 0.5% per year, respectively). Participants in the higher tertile of baseline body fatness presented a significantly faster decline of MQ than the rest of the population (P = .021). Similar results were observed when body mass, TFM, and TLM were modeled as time‐dependent predictors. Conclusions Body composition, but not weight nor BMI, is associated with future MQ decline, suggesting that preventive strategies aimed at maintaining good MQ with aging should specifically target body composition features. PMID:28198113

Effect of survey instrument on participation in a follow-up study: a randomization study of a mailed questionnaire versus a computer-assisted telephone interview

PubMed Central

2012-01-01

Background Many epidemiological and public health surveys report increasing difficulty obtaining high participation rates. We conducted a pilot follow-up study to determine whether a mailed or telephone survey would better facilitate data collection in a subset of respondents to an earlier telephone survey conducted as part of the National Birth Defects Prevention Study. Methods We randomly assigned 392 eligible mothers to receive a self-administered, mailed questionnaire (MQ) or a computer-assisted telephone interview (CATI) using similar recruitment protocols. If mothers gave permission to contact the fathers, fathers were recruited to complete the same instrument (MQ or CATI) as mothers. Results Mothers contacted for the MQ, within all demographic strata examined, were more likely to participate than those contacted for the CATI (86.6% vs. 70.6%). The median response time for mothers completing the MQ was 17 days, compared to 29 days for mothers completing the CATI. Mothers completing the MQ also required fewer reminder calls or letters to finish participation versus those assigned to the CATI (median 3 versus 6), though they were less likely to give permission to contact the father (75.0% vs. 85.8%). Fathers contacted for the MQ, however, had higher participation compared to fathers contacted for the CATI (85.2% vs. 54.5%). Fathers recruited to the MQ also had a shorter response time (median 17 days) and required fewer reminder calls and letters (median 3 reminders) than those completing the CATI (medians 28 days and 6 reminders). Conclusions We concluded that offering a MQ substantially improved participation rates and reduced recruitment effort compared to a CATI in this study. While a CATI has the advantage of being able to clarify answers to complex questions or eligibility requirements, our experience suggests that a MQ might be a good survey option for some studies. PMID:22849754

Spectroscopic and molecular docking studies on the charge transfer complex of bovine serum albumin with quinone in aqueous medium and its influence on the ligand binding property of the protein.

PubMed

Satheshkumar, Angupillai; Elango, Kuppanagounder P

2014-09-15

The spectral techniques such as UV-Vis, (1)H NMR and fluorescence and electrochemical experiments have been employed to investigate the interaction between 2-methoxy-3,5,6-trichloro-1,4-benzoquinone (MQ; a water soluble quinone) and bovine serum albumin (BSA) in aqueous medium. The fluorescence of BSA was quenched by MQ via formation of a 1:1 BSA-MQ charge transfer adduct with a formation constant of 3.3×10(8) L mol(-1). Based on the Forster's theory the binding distance between them is calculated as 2.65 nm indicating high probability of binding. For the first time, influence of quinone on the binding property of various types of ligands such as aspirin, ascorbic acid, nicotinimide and sodium stearate has also been investigated. The results indicated that the strong and spontaneous binding existing between BSA and MQ, decreased the intensity of binding of these ligands with BSA. Since Tryptophan (Trp) is the basic residue present in BSA, a comparison between binding property of Trp-MQ adduct with that of BSA-MQ with these ligands has also been attempted. 1H NMR titration study indicated that the Trp forms a charge transfer complex with MQ, which reduces the interaction of Trp with the ligands. Molecular docking study supported the fact that the quinone interacts with the Trp212 unit of the BSA and the free energy change of binding (ΔG) for the BSA-MQ complex was found to be -46 kJ mol(-1), which is comparable to our experimental free energy of binding (-49 kJ mol(-1)) obtained from fluorescence study. Copyright © 2014 Elsevier B.V. All rights reserved.

Cotrimoxazole prophylaxis versus mefloquine intermittent preventive treatment to prevent malaria in HIV-infected pregnant women: two randomized controlled trials.

PubMed

Denoeud-Ndam, Lise; Zannou, Djimon-Marcel; Fourcade, Camille; Taron-Brocard, Clément; Porcher, Raphaël; Atadokpede, Felix; Komongui, Didier G; Dossou-Gbete, Lucien; Afangnihoun, Aldric; Ndam, Nicaise T; Girard, Pierre-Marie; Cot, Michel

2014-02-01

Malaria during pregnancy has serious consequences that are worsened by HIV infection. Malaria preventive measures for HIV-infected pregnant women include cotrimoxazole (CTX) prophylaxis given to prevent HIV-related opportunistic infections and also protective against malaria, or intermittent preventive treatment (IPTp) with an antimalarial drug. Here, we present the first study evaluating CTX efficacy versus mefloquine (MQ)-IPTp, alone and in combination, in HIV-infected pregnant women. We conducted 2 randomized, open-label, noninferiority trials in Benin. In the CTX-mandatory trial, HIV-infected women with CD4 counts of <350 per cubic millimeter received CTX either alone or with MQ-IPTp (N = 292). In the CTX-not-mandatory trial (CD4 count >350/mm), CTX was compared with MQ-IPTp (N = 140). In both the trials, the primary end point was microscopic placental parasitemia. At delivery, 1 woman in each CTX-alone treatment group exhibited placental parasitemia, versus no women in the groups receiving MQ. CTX alone demonstrated noninferiority in the CTX-mandatory trial. However, polymerase chain reaction-detected placental parasitemia was markedly reduced in the CTX + MQ group compared with CTX alone (0/105 vs. 5/103, P = 0.03). Because of insufficient recruitment in the CTX-not-mandatory trial, noninferiority could not be conclusively assessed. Dizziness and vomiting of moderate intensity were reported by 34%-37% of women receiving MQ in both the trials, versus 0%-3% in CTX groups (P < 0.0001). No serious adverse events related to these drugs were found. CTX alone provided adequate protection against malaria in HIV-infected pregnant women, although MQ-IPTp showed higher efficacy against placental infection. Although more frequently associated with dizziness and vomiting, MQ-IPTp may be an effective alternative given concerns about parasite resistance to CTX.

Spectroscopic and molecular docking studies on the charge transfer complex of bovine serum albumin with quinone in aqueous medium and its influence on the ligand binding property of the protein

NASA Astrophysics Data System (ADS)

Satheshkumar, Angupillai; Elango, Kuppanagounder P.

2014-09-01

The spectral techniques such as UV-Vis, 1H NMR and fluorescence and electrochemical experiments have been employed to investigate the interaction between 2-methoxy-3,5,6-trichloro-1,4-benzoquinone (MQ; a water soluble quinone) and bovine serum albumin (BSA) in aqueous medium. The fluorescence of BSA was quenched by MQ via formation of a 1:1 BSA-MQ charge transfer adduct with a formation constant of 3.3 × 108 L mol-1. Based on the Forster’s theory the binding distance between them is calculated as 2.65 nm indicating high probability of binding. For the first time, influence of quinone on the binding property of various types of ligands such as aspirin, ascorbic acid, nicotinimide and sodium stearate has also been investigated. The results indicated that the strong and spontaneous binding existing between BSA and MQ, decreased the intensity of binding of these ligands with BSA. Since Tryptophan (Trp) is the basic residue present in BSA, a comparison between binding property of Trp-MQ adduct with that of BSA-MQ with these ligands has also been attempted. 1H NMR titration study indicated that the Trp forms a charge transfer complex with MQ, which reduces the interaction of Trp with the ligands. Molecular docking study supported the fact that the quinone interacts with the Trp212 unit of the BSA and the free energy change of binding (ΔG) for the BSA-MQ complex was found to be -46 kJ mol-1, which is comparable to our experimental free energy of binding (-49 kJ mol-1) obtained from fluorescence study.

Pharmacological characterization of memoquin, a multi-target compound for the treatment of Alzheimer's disease.

PubMed

Capurro, Valeria; Busquet, Perrine; Lopes, Joao Pedro; Bertorelli, Rosalia; Tarozzo, Glauco; Bolognesi, Maria Laura; Piomelli, Daniele; Reggiani, Angelo; Cavalli, Andrea

2013-01-01

Alzheimer's disease (AD) is characterized by progressive loss of cognitive function, dementia and altered behavior. Over 30 million people worldwide suffer from AD and available therapies are still palliative rather than curative. Recently, Memoquin (MQ), a quinone-bearing polyamine compound, has emerged as a promising anti-AD lead candidate, mainly thanks to its multi-target profile. MQ acts as an acetylcholinesterase and β-secretase-1 inhibitor, and also possesses anti-amyloid and anti-oxidant properties. Despite this potential interest, in vivo behavioral studies with MQ have been limited. Here, we report on in vivo studies with MQ (acute and sub-chronic treatments; 7-15 mg/kg per os) carried out using two different mouse models: i) scopolamine- and ii) beta-amyloid peptide- (Aβ-) induced amnesia. Several aspects related to memory were examined using the T-maze, the Morris water maze, the novel object recognition, and the passive avoidance tasks. At the dose of 15 mg/kg, MQ was able to rescue all tested aspects of cognitive impairment including spatial, episodic, aversive, short and long-term memory in both scopolamine- and Aβ-induced amnesia models. Furthermore, when tested in primary cortical neurons, MQ was able to fully prevent the Aβ-induced neurotoxicity mediated by oxidative stress. The results support the effectiveness of MQ as a cognitive enhancer, and highlight the value of a multi-target strategy to address the complex nature of cognitive dysfunction in AD.

Pharmacological Characterization of Memoquin, a Multi-Target Compound for the Treatment of Alzheimer's Disease

PubMed Central

Capurro, Valeria; Busquet, Perrine; Lopes, Joao Pedro; Bertorelli, Rosalia; Tarozzo, Glauco; Bolognesi, Maria Laura; Piomelli, Daniele; Reggiani, Angelo; Cavalli, Andrea

2013-01-01

Alzheimer's disease (AD) is characterized by progressive loss of cognitive function, dementia and altered behavior. Over 30 million people worldwide suffer from AD and available therapies are still palliative rather than curative. Recently, Memoquin (MQ), a quinone-bearing polyamine compound, has emerged as a promising anti-AD lead candidate, mainly thanks to its multi-target profile. MQ acts as an acetylcholinesterase and β-secretase-1 inhibitor, and also possesses anti-amyloid and anti-oxidant properties. Despite this potential interest, in vivo behavioral studies with MQ have been limited. Here, we report on in vivo studies with MQ (acute and sub-chronic treatments; 7–15 mg/kg per os) carried out using two different mouse models: i) scopolamine- and ii) beta-amyloid peptide- (Aβ-) induced amnesia. Several aspects related to memory were examined using the T-maze, the Morris water maze, the novel object recognition, and the passive avoidance tasks. At the dose of 15 mg/kg, MQ was able to rescue all tested aspects of cognitive impairment including spatial, episodic, aversive, short and long-term memory in both scopolamine- and Aβ-induced amnesia models. Furthermore, when tested in primary cortical neurons, MQ was able to fully prevent the Aβ-induced neurotoxicity mediated by oxidative stress. The results support the effectiveness of MQ as a cognitive enhancer, and highlight the value of a multi-target strategy to address the complex nature of cognitive dysfunction in AD. PMID:23441223

MQ-MAC: A Multi-Constrained QoS-Aware Duty Cycle MAC for Heterogeneous Traffic in Wireless Sensor Networks

PubMed Central

Monowar, Muhammad Mostafa; Rahman, Md. Obaidur; Hong, Choong Seon; Lee, Sungwon

2010-01-01

Energy conservation is one of the striking research issues now-a-days for power constrained wireless sensor networks (WSNs) and hence, several duty-cycle based MAC protocols have been devised for WSNs in the last few years. However, assimilation of diverse applications with different QoS requirements (i.e., delay and reliability) within the same network also necessitates in devising a generic duty-cycle based MAC protocol that can achieve both the delay and reliability guarantee, termed as multi-constrained QoS, while preserving the energy efficiency. To address this, in this paper, we propose a Multi-constrained QoS-aware duty-cycle MAC for heterogeneous traffic in WSNs (MQ-MAC). MQ-MAC classifies the traffic based on their multi-constrained QoS demands. Through extensive simulation using ns-2 we evaluate the performance of MQ-MAC. MQ-MAC provides the desired delay and reliability guarantee according to the nature of the traffic classes as well as achieves energy efficiency. PMID:22163439

Design and Development of a Salbutamol Intake Detector for Low Respiratory Treatment

NASA Astrophysics Data System (ADS)

Vui Hin, Tsen; Ilyani Ramli, Nur

2017-08-01

This paper proposed a new salbutamol intake detector design using asthma spacer and gas sensor. The device enable real time monitoring of propellant level inhaled by the infant which will decrease the recovery time of the asthma attack. Microcontroller Arduino UNO is program to control the input and output of the system. MQ6 gas sensor detecting the propellant Hydrofluoroalkane from the metered dose inhaler (MDI) canister and demonstrated the level of propellant inhaled on the LCD in real time. MQ6 gas sensor suitable used to detect concentration of propellant inside the asthma spacer due to it is low sensitive to natural gas where include the carbon dioxide exhaled by the infant. Besides this, MQ6 gas sensor also highly sensitive to propane and the preview aerosol inventor mentioned propane as propellant which used for MDI to push the salbutamol out from MDI canister. Therefore, MQ6 gas sensor is suitable to detect propellant inside asthma spacer. The output voltage of MQ6 in initial state where no propellant inside asthma spacer is between 0.55V and 0.65V. Furthermore, when the MDI canister is been pressed, the concentration of propellant is increased and the output voltage of MQ6 gas sensor also increased in ranged between 1.1V and 1.2V.

Cell Based Metabolic Barriers to Glucose Diffusion: Macrophages and Continuous Glucose Monitoring

PubMed Central

Klueh, Ulrike; Frailey, Jackman; Qiao, Yi; Antar, Omar; Kreutzer, Donald L.

2014-01-01

It is assumed that MQ are central to glucose sensor bio-fouling and therefore have a major negative impact on continuous glucose monitoring (CGM) performance in vivo. However to our knowledge there is no data in the literature to directly support or refute this assumption. Since glucose and oxygen (O2) are key to glucose sensor function in vivo, understanding and controlling glucose and O2 metabolic activity of MQ is likely key to successful glucose sensor performance. We hypothesized that the accumulation of MQ at the glucose sensor-tissue interface will act as “Cell Based Metabolic Barriers” (CBMB) to glucose diffusing from the interstitial tissue compartment to the implanted glucose sensor and as such creating an artificially low sensor output, thereby compromising sensor function and CGM. Our studies demonstrated that 1) direct injections of MQ at in vivo sensor implantation sites dramatically decreased sensor output (measured in nA), 2) addition of MQ to glucose sensors in vitro resulted in a rapid and dramatic fall in sensor output and 3) lymphocytes did not affect sensor function in vitro or in vivo. These data support our hypothesis that MQ can act as metabolic barriers to glucose and O2 diffusion in vivo and in vitro. PMID:24461328

Cell based metabolic barriers to glucose diffusion: macrophages and continuous glucose monitoring.

PubMed

Klueh, Ulrike; Frailey, Jackman T; Qiao, Yi; Antar, Omar; Kreutzer, Donald L

2014-03-01

It is assumed that MQ are central to glucose sensor bio-fouling and therefore have a major negative impact on continuous glucose monitoring (CGM) performance in vivo. However to our knowledge there is no data in the literature to directly support or refute this assumption. Since glucose and oxygen (O2) are key to glucose sensor function in vivo, understanding and controlling glucose and O2 metabolic activity of MQ is likely key to successful glucose sensor performance. We hypothesized that the accumulation of MQ at the glucose sensor-tissue interface will act as "Cell Based Metabolic Barriers" (CBMB) to glucose diffusing from the interstitial tissue compartment to the implanted glucose sensor and as such creating an artificially low sensor output, thereby compromising sensor function and CGM. Our studies demonstrated that 1) direct injections of MQ at in vivo sensor implantation sites dramatically decreased sensor output (measured in nA), 2) addition of MQ to glucose sensors in vitro resulted in a rapid and dramatic fall in sensor output and 3) lymphocytes did not affect sensor function in vitro or in vivo. These data support our hypothesis that MQ can act as metabolic barriers to glucose and O2 diffusion in vivo and in vitro. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intermittent treatment for the prevention of malaria during pregnancy in Benin: a randomized, open-label equivalence trial comparing sulfadoxine-pyrimethamine with mefloquine.

PubMed

Briand, Valérie; Bottero, Julie; Noël, Harold; Masse, Virginie; Cordel, Hugues; Guerra, José; Kossou, Hortense; Fayomi, Benjamin; Ayemonna, Paul; Fievet, Nadine; Massougbodji, Achille; Cot, Michel

2009-09-15

In the context of the increasing resistance to sulfadoxine-pyrimethamine (SP), we evaluated the efficacy of mefloquine (MQ) for intermittent preventive treatment during pregnancy (IPTp). A multicenter, open-label equivalence trial was conducted in Benin from July 2005 through April 2008. Women of all gravidities were randomized to receive SP (1500 mg of sulfadoxine and 75 mg of pyrimethamine) or 15 mg/kg MQ in a single intake twice during pregnancy. The primary end point was the proportion of low-birth-weight (LBW) infants (body weight, <2500 g; equivalence margin, 5%). A total of 1601 women were randomized to receive MQ (n=802)or SP (n=799).In the modified intention-to-treat analysis, which assessed only live singleton births, 59 (8%) of 735 women who were given MQ and 72 (9.8%) of 730 women who were given SP gave birth to LBW infants (difference between low birth weights in treatment groups, -1.8%; 95% confidence interval [CI], -4.8% to 1.1%]), establishing equivalence between the drugs. The per-protocol analysis showed consistent results. MQ was more efficacious than SP in preventing placental malaria (prevalence, 1.7% vs 4.4% of women; P = .005),clinical malaria (incidence rate, 26 cases/10,000 person-months vs. 68 cases/10,000 person-months; P = .007) and maternal anemia at delivery (as defined by a hemoglobin level <10 g/dL) (prevalence, 16% vs 20%; marginally significant at P = .09). Adverse events (mainly vomiting, dizziness, tiredness, and nausea) were more commonly associated with the use of MQ (prevalence, 78% vs 32%; P < 10(-3)) One woman in the MQ group had severe neuropsychiatric symptoms. MQ proved to be highly efficacious--both clinically and parasitologically--for use as IPTp. However, its low tolerability might impair its effectiveness and requires further investigations.

Multiple Genetic Backgrounds of the Amplified Plasmodium falciparum Multidrug Resistance (pfmdr1) Gene and Selective Sweep of 184F Mutation in Cambodia

PubMed Central

Vinayak, Sumiti; Alam, Md Tauqeer; Sem, Rithy; Shah, Naman K.; Susanti, Augustina I.; Lim, Pharath; Muth, Sinuon; Maguire, Jason D.; Rogers, William O.; Fandeur, Thierry; Barnwell, John W.; Escalante, Ananias A.; Wongsrichanalai, Chansuda; Ariey, Frederick; Meshnick, Steven R.; Udhayakumar, Venkatachalam

2011-01-01

Background The emergence of artesunate-mefloquine (AS+MQ)–resistant Plasmodium falciparum in the Thailand-Cambodia region is a major concern for malaria control. Studies indicate that copy number increase and key alleles in the pfmdr1 gene are associated with AS+MQ resistance. In the present study, we investigated evidence for a selective sweep around pfmdr1 because of the spread of adaptive mutation and/or multiple copies of this gene in the P. falciparum population in Cambodia. Methods We characterized 13 microsatellite loci flanking (± 99 kb) pfmdr1 in 93 single-clone P. falciparum infections, of which 31 had multiple copies and 62 had a single copy of the pfmdr1 gene. Results Genetic analysis revealed no difference in the mean (± standard deviation) expected heterozygosity (He) at loci around single (0.75 ± 0.03) and multiple (0.76 ± 0.04) copies of pfmdr1. Evidence of genetic hitchhiking with the selective sweep of certain haplotypes was seen around mutant (184F) pfmdr1 allele, irrespective of the copy number. There was an overall reduction of 28% in mean He (± SD) around mutant allele (0.56 ± 0.05), compared with wild-type allele (0.84 ± 0.02). Significant linkage disequilibrium was also observed between the loci flanking mutant pfmdr1 allele. Conclusion The 184F mutant allele is under selection, whereas amplification of pfmdr1 gene in this population occurs on multiple genetic backgrounds. PMID:20367478

Comparing real-time and conventional PCR to culture-based methods for detecting and quantifying Escherichia coli O157 in cattle feces.

PubMed

Jacob, M E; Bai, J; Renter, D G; Rogers, A T; Shi, X; Nagaraja, T G

2014-02-01

Detection of Escherichia coli O157 in cattle feces has traditionally used culture-based methods; PCR-based methods have been suggested as an alternative. We aimed to determine if multiplex real-time (mq) or conventional PCR methods could reliably detect cattle naturally shedding high (≥10(4) CFU/g of feces) and low (∼10(2) CFU/g of feces) concentrations of E. coli O157. Feces were collected from pens of feedlot cattle and evaluated for E. coli O157 by culture methods. Samples were categorized as (i) high shedders, (ii) immunomagnetic separation (IMS) positive after enrichment, or (iii) culture negative. DNA was extracted pre- and postenrichment from 100 fecal samples from each category (high shedder, IMS positive, culture negative) and subjected to mqPCR and conventional PCR assays based on detecting three genes, rfbE, stx1, and stx2. In feces from cattle determined to be E. coli O157 high shedders by culture, 37% were positive by mqPCR prior to enrichment; 85% of samples were positive after enrichment. In IMS-positive samples, 4% were positive by mqPCR prior to enrichment, while 43% were positive after enrichment. In culture-negative feces, 7% were positive by mqPCR prior to enrichment, and 40% were positive after enrichment. The proportion of high shedder-positive and culture-positive (high shedder and IMS) samples were significantly different from mqPCR-positive samples before and after enrichment (P < 0.01). Similar results were observed for conventional PCR. Our data suggest that mqPCR and conventional PCR are most useful in identifying high shedder animals and may not be an appropriate substitute to culture-based methods for detection of E. coli O157 in cattle feces.

A spherical electron cloud hopping model for studying product branching ratios of dissociative recombination.

PubMed

Yu, Hua-Gen

2008-05-21

A spherical electron cloud hopping (SECH) model is proposed to study the product branching ratios of dissociative recombination (DR) of polyatomic systems. In this model, the fast electron-captured process is treated as an instantaneous hopping of a cloud of uniform spherical fractional point charges onto a target M+q ion (or molecule). The sum of point charges (-1) simulates the incident electron. The sphere radius is determined by a critical distance (Rc eM) between the incoming electron (e-) and the target, at which the potential energy of the e(-)-M+q system is equal to that of the electron-captured molecule M+q(-1) in a symmetry-allowed electronic state with the same structure as M(+q). During the hopping procedure, the excess energies of electron association reaction are dispersed in the kinetic energies of M+q(-1) atoms to conserve total energy. The kinetic energies are adjusted by linearly adding atomic momenta in the direction of driving forces induced by the scattering electron. The nuclear dynamics of the resultant M+q(-1) molecule are studied by using a direct ab initio dynamics method on the adiabatic potential energy surface of M+q(-1), or together with extra adiabatic surface(s) of M+q(-1). For the latter case, the "fewest switches" surface hopping algorithm of Tully was adapted to deal with the nonadiabaticity in trajectory propagations. The SECH model has been applied to study the DR of both CH+ and H3O+(H2O)2. The theoretical results are consistent with the experiment. It was found that water molecules play an important role in determining the product branching ratios of the molecular cluster ion.

Onion quercetin monoglycosides alter microbial activity and increase antioxidant capacity.

PubMed

Grzelak-Błaszczyk, Katarzyna; Milala, Joanna; Kosmala, Monika; Kołodziejczyk, Krzysztof; Sójka, Michał; Czarnecki, Andrzej; Klewicki, Robert; Juśkiewicz, Jerzy; Fotschki, Bartosz; Jurgoński, Adam

2018-06-01

The effects on fermentation processes in the digestive tract, the biochemical parameters and antioxidant capacity of blood in rats fed high-fat diets with quercetin (Q) and quercetin with quercetin monoglycosides (Q+MQ) preparations obtained from onion waste were evaluated. Four groups of eight animals were fed for 4 weeks with a control diet (C), a high-fat diet (HF) and high-fat diets with 0.15% addition of Q and Q+MQ preparations. HF caused an increase in alanine transaminase (ALT), non-high-density lipoprotein (non-HDL) and the atherogenic index AII vs. C and a decrease in the proportion of HDL in total cholesterol (TC). Q and Q+MQ showed a tendency to moderate the values aspartate transaminase (P=.087), ALT (P<.05), TC (P=.068), non-HDL cholesterol (P<.05), triglycerides (P=.064) and the atherogenic index AII (P<.05). Q+MQ significantly increased the activity of α-glucosidase (P<.05 vs. HF), β-glucosidase (P<.05) and β-galactosidase (P<.05 vs. C and Q). Q increased activity of β-glucosidase (P<.001 vs. C and HF). Both increased the activity of β-glucuronidase (P<.05 vs. C and HF). Both increased the antioxidant capacity of the hydrophilic fraction in serum (P<.05 vs. C and HF), and Q enhanced that of the lipid fraction (P<.001). Q preparation contained 70% quercetin, and Q+MQ preparation contained 29% quercetin and 13% quercetin monoglycosides, mainly quercetin-4'-glucoside. Both exhibited high antioxidant capacity. Supplementation with Q and Q+MQ increased the enzymatic activity of the intestinal microbiota and the antioxidant capacity of blood and revealed a tendency to improve the blood lipid profile. MQ were particularly effective in stimulating the bacterial enzymatic activity. Copyright © 2018 Elsevier Inc. All rights reserved.

Weight status is associated with cross-sectional trajectories of motor co-ordination across childhood.

PubMed

Lopes, V P; Stodden, D F; Rodrigues, L P

2014-11-01

Research indicates the development of motor co-ordination (MC) may be an important contributing factor to positive or negative weight trajectories across childhood. To analyse cross-sectional associations between MC and weight status in children (boys n = 3344 - girls n = 3281), aged 6-11 years and assess overweight/obese risk across different ages. Body mass index (BMI) was calculated [body mass (kg)/height (m(2))]. MC was evaluated using the Körperkoordination Test für Kinder (KTK) and a motor quotient (MQ) was calculated. MQ distribution data were split into tertiles. The effect of age, sex and MQ tertiles on BMI and MC was tested with a factorial anova. A logistic regression also was performed to calculate odd ratios (OR) for being overweight/obese at each age. Children with higher MQ demonstrated lower BMI levels (F(2,6224) = 222.09; P < 0.001). Differences in BMI among MQ tertiles became larger across age (F(10,6224) = 4.53; P < 0.001). The OR of being overweight/obese in both sexes within the lowest MQ tertile increased in each age group from 6 to 11 years. Specifically, OR increased from 2.26 to 27.77 and from 1.87 to 6.81 in boys and girls respectively. Children with low levels of MC have a higher risk of being overweight/obese and this risk increases with age. © 2013 John Wiley & Sons Ltd.

Small private key MQPKS on an embedded microprocessor.

PubMed

Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

2014-03-19

Multivariate quadratic (MQ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key MQ scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing MQ on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key MQ scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES) accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012.

Ex Vivo Drug Susceptibility Testing and Molecular Profiling of Clinical Plasmodium falciparum Isolates from Cambodia from 2008 to 2013 Suggest Emerging Piperaquine Resistance

PubMed Central

Chaorattanakawee, Suwanna; Saunders, David L.; Sea, Darapiseth; Chanarat, Nitima; Yingyuen, Kritsanai; Sundrakes, Siratchana; Saingam, Piyaporn; Buathong, Nillawan; Sriwichai, Sabaithip; Chann, Soklyda; Se, Youry; Yom, You; Heng, Thay Kheng; Kong, Nareth; Kuntawunginn, Worachet; Tangthongchaiwiriya, Kuntida; Jacob, Christopher; Takala-Harrison, Shannon; Plowe, Christopher; Lin, Jessica T.; Chuor, Char Meng; Prom, Satharath; Tyner, Stuart D.; Gosi, Panita; Teja-Isavadharm, Paktiya; Lon, Chanthap

2015-01-01

Cambodia's first-line artemisinin combination therapy, dihydroartemisinin-piperaquine (DHA-PPQ), is no longer sufficiently curative against multidrug-resistant Plasmodium falciparum malaria at some Thai-Cambodian border regions. We report recent (2008 to 2013) drug resistance trends in 753 isolates from northern, western, and southern Cambodia by surveying for ex vivo drug susceptibility and molecular drug resistance markers to guide the selection of an effective alternative to DHA-PPQ. Over the last 3 study years, PPQ susceptibility declined dramatically (geomean 50% inhibitory concentration [IC50] increased from 12.8 to 29.6 nM), while mefloquine (MQ) sensitivity doubled (67.1 to 26 nM) in northern Cambodia. These changes in drug susceptibility were significantly associated with a decreased prevalence of P. falciparum multidrug resistance 1 gene (Pfmdr1) multiple copy isolates and coincided with the timing of replacing artesunate-mefloquine (AS-MQ) with DHA-PPQ as the first-line therapy. Widespread chloroquine resistance was suggested by all isolates being of the P. falciparum chloroquine resistance transporter gene CVIET haplotype. Nearly all isolates collected from the most recent years had P. falciparum kelch13 mutations, indicative of artemisinin resistance. Ex vivo bioassay measurements of antimalarial activity in plasma indicated 20% of patients recently took antimalarials, and their plasma had activity (median of 49.8 nM DHA equivalents) suggestive of substantial in vivo drug pressure. Overall, our findings suggest DHA-PPQ failures are associated with emerging PPQ resistance in a background of artemisinin resistance. The observed connection between drug policy changes and significant reduction in PPQ susceptibility with mitigation of MQ resistance supports reintroduction of AS-MQ, in conjunction with monitoring of the P. falciparum mdr1 copy number, as a stop-gap measure in areas of DHA-PPQ failure. PMID:26014942

Application of Differential Colorimetry To Evaluate Anthocyanin-Flavonol-Flavanol Ternary Copigmentation Interactions in Model Solutions.

PubMed

Gordillo, Belén; Rodríguez-Pulido, Francisco J; González-Miret, M Lourdes; Quijada-Morín, Natalia; Rivas-Gonzalo, Julián C; García-Estévez, Ignacio; Heredia, Francisco J; Escribano-Bailón, M Teresa

2015-09-09

The combined effect of anthocyanin-flavanol-flavonol ternary interactions on the colorimetric and chemical stability of malvidin-3-glucoside has been studied. Model solutions with fixed malvidin-3-glucoside/(+)-catechin ratio (MC) and variable quercetin-3-β-d-glucoside concentration (MC+Q) and solutions with fixed malvidin-3-glucoside/quercetin-3-β-d-glucoside ratio (MQ) and variable (+)-catechin concentration (MQ+C) were tested at levels closer to those existing in wines. Color variations during storage were evaluated by differential colorimetry. Changes in the anthocyanin concentration were monitored by HPLC-DAD. CIELAB color-difference formulas were demonstrated to be of practical interest to assess the stronger and more stable interaction of quercetin-3-β-d-glucoside with MC binary mixture than (+)-catechin with MQ mixture. The results imply that MC+Q ternary solutions kept their intensity and bluish tonalities for a longer time in comparison to MQ+C solutions. The stability of malvidin-3-glucoside improves when the concentration of quercetin-3-β-d-glucoside increases in MC+Q mixtures, whereas the addition of (+)-catechin in MQ+C mixtures resulted in an opposite effect.

Quantum attack-resistent certificateless multi-receiver signcryption scheme.

PubMed

Li, Huixian; Chen, Xubao; Pang, Liaojun; Shi, Weisong

2013-01-01

The existing certificateless signcryption schemes were designed mainly based on the traditional public key cryptography, in which the security relies on the hard problems, such as factor decomposition and discrete logarithm. However, these problems will be easily solved by the quantum computing. So the existing certificateless signcryption schemes are vulnerable to the quantum attack. Multivariate public key cryptography (MPKC), which can resist the quantum attack, is one of the alternative solutions to guarantee the security of communications in the post-quantum age. Motivated by these concerns, we proposed a new construction of the certificateless multi-receiver signcryption scheme (CLMSC) based on MPKC. The new scheme inherits the security of MPKC, which can withstand the quantum attack. Multivariate quadratic polynomial operations, which have lower computation complexity than bilinear pairing operations, are employed in signcrypting a message for a certain number of receivers in our scheme. Security analysis shows that our scheme is a secure MPKC-based scheme. We proved its security under the hardness of the Multivariate Quadratic (MQ) problem and its unforgeability under the Isomorphism of Polynomials (IP) assumption in the random oracle model. The analysis results show that our scheme also has the security properties of non-repudiation, perfect forward secrecy, perfect backward secrecy and public verifiability. Compared with the existing schemes in terms of computation complexity and ciphertext length, our scheme is more efficient, which makes it suitable for terminals with low computation capacity like smart cards.

MQ-4C Triton Unmanned Aircraft System (MQ-4C Triton)

DTIC Science & Technology

2015-12-01

will respond to theater level operational or national strategic taskings. MQ-4C Triton December 2015 SAR March 23, 2016 15:26:01 UNCLASSIFIED 6...88% at a mission radius of 2,000 nm Level of Interoperability 1-5 BLOS and LOS from MOB/ FOB (Land Based) MCS BLOS and LOS from MOB/ FOB (Land...MCS UA Mission Radius >=3,000 nm >=3,000 nm >=2,000 nm TBD >=2,000 nm Level Of Interoperability 2 Capability LOS/BLOS multi-ISR payload reception to

MQ-9 Reaper Unmanned Aircraft System (MQ-9 Reaper)

DTIC Science & Technology

2013-12-01

Milestone C ACAT II Block 1 FEB 2008 FEB 2008 FEB 2008 FEB 2008 IOT&E for Block 1 MAY 2008 MAY 2008 MAY 2008 MAY 2008 RAA SEP 2010 JUN 2012 JUN 2012 JUN...milestone change. Memo MQ-9 Reaper December 2013 SAR April 16, 2014 17:17:09 UNCLASSIFIED 9 RAA includes two fixed GCSs, two mobile GCSs...Control Station IOT&E - Initial Operational Test and Evaluation PMAI - Primary Mission Aircraft Inventory PO - Program Office RAA - Required Assets

Disruption of Pyridine Nucleotide Redox Status During Oxidative Challenge at Normal and Low-Glucose States: Implications for Cellular Adenosine Triphosphate, Mitochondrial Respiratory Activity, and Reducing Capacity in Colon Epithelial Cells

PubMed Central

Circu, Magdalena L.; Maloney, Ronald E.

2011-01-01

Abstract We recently demonstrated that menadione (MQ), a redox cycling quinone, mediated the loss of mitochondrial glutathione/glutathione disulfide redox balance. In this study, we showed that MQ significantly disrupted cellular pyridine nucleotide (NAD+/NADH, NADP+/NADPH) redox balance that compromised cellular ATP, mitochondrial respiratory activity, and NADPH-dependent reducing capacity in colonic epithelial cells, a scenario that was exaggerated by low glucose. In the cytosol, MQ induced NAD+ loss concurrent with increased NADP+ and NAD kinase activity, but decreased NADPH. In the mitochondria, NADH loss occurred in conjunction with increased nicotinamide nucleotide transhydrogenase activity and NADP+, and decreased NADPH. These results are consistent with cytosolic NAD+-to-NADP+ and mitochondrial NADH-to-NADPH shifts, but compromised NADPH availability. Thus, despite the sacrifice of NAD+/NADH in favor of NADPH generation, steady-state NADPH levels were not maintained during MQ challenge. Impairments of cellular bioenergetics were evidenced by ATP losses and increased mitochondrial O2 dependence of pyridine nucleotide oxidation–reduction; half-maximal oxidation (P50) was 10-fold higher in low glucose, which was lowered by glutamate or succinate supplementation. This exaggerated O2 dependence is consistent with increased O2 diversion to nonmitochondrial O2 consumption by MQ-semiquinone redox cycling secondary to decreased NADPH-dependent MQ detoxication at low glucose, a situation that was corrected by glucose-sparing mitochondrial substrates. Antioxid. Redox Signal. 14, 2151–2162. PMID:21083422

An Open-Label, Randomised Study of Dihydroartemisinin-Piperaquine Versus Artesunate-Mefloquine for Falciparum Malaria in Asia

PubMed Central

Valecha, Neena; Phyo, Aung Pyae; Mayxay, Mayfong; Newton, Paul N.; Krudsood, Srivicha; Keomany, Sommay; Khanthavong, Maniphone; Pongvongsa, Tiengkham; Ruangveerayuth, Ronnatrai; Uthaisil, Chirapong; Ubben, David; Duparc, Stephan; Bacchieri, Antonella; Corsi, Marco; Rao, Bappanad H. K.; Bhattacharya, Prabash C.; Dubhashi, Nagesh; Ghosh, Susanta K.; Dev, Vas; Kumar, Ashwani; Pukittayakamee, Sasithon

2010-01-01

Background The artemisinin-based combination treatment (ACT) of dihydroartemisinin (DHA) and piperaquine (PQP) is a promising novel anti-malarial drug effective against multi-drug resistant falciparum malaria. The aim of this study was to show non-inferiority of DHA/PQP vs. artesunate-mefloquine (AS+MQ) in Asia. Methods and Findings This was an open-label, randomised, non-inferiority, 63-day follow-up study conducted in Thailand, Laos and India. Patients aged 3 months to 65 years with Plasmodium falciparum mono-infection or mixed infection were randomised with an allocation ratio of 2∶1 to a fixed-dose DHA/PQP combination tablet (adults: 40 mg/160 mg; children: 20 mg/320 mg; n = 769) or loose combination of AS+MQ (AS: 50 mg, MQ: 250 mg; n = 381). The cumulative doses of study treatment over the 3 days were of about 6.75 mg/kg of DHA and 54 mg/kg of PQP and about 12 mg/kg of AS and 25 mg/kg of MQ. Doses were rounded up to the nearest half tablet. The primary endpoint was day-63 polymerase chain reaction (PCR) genotype-corrected cure rate. Results were 87.9% for DHA/PQP and 86.6% for AS+MQ in the intention-to-treat (ITT; 97.5% one-sided confidence interval, CI: >−2.87%), and 98.7% and 97.0%, respectively, in the per protocol population (97.5% CI: >−0.39%). No country effect was observed. Kaplan-Meier estimates of proportions of patients with new infections on day 63 (secondary endpoint) were significantly lower for DHA/PQP than AS+MQ: 22.7% versus 30.3% (p = 0.0042; ITT). Overall gametocyte prevalence (days 7 to 63; secondary endpoint), measured as person-gametocyte-weeks, was significantly higher for DHA/PQP than AS+MQ (10.15% versus 4.88%; p = 0.003; ITT). Fifteen serious adverse events were reported, 12 (1.6%) in DHA/PQP and three (0.8%) in AS+MQ, among which six (0.8%) were considered related to DHA/PQP and three (0.8%) to AS+MQ. Conclusions DHA/PQP was a highly efficacious drug for P. falciparum malaria in areas where multidrug parasites are prevalent. The DHA/PQP combination can play an important role in the first-line treatment of uncomplicated falciparum malaria. Trial Registration Controlled-Trials.com ISRCTN81306618 PMID:20689583

Intermittent Preventive Treatment of Malaria in Pregnancy with Mefloquine in HIV-Infected Women Receiving Cotrimoxazole Prophylaxis: A Multicenter Randomized Placebo-Controlled Trial

PubMed Central

Abdulla, Salim; Aponte, John J.; Bulo, Helder; Kabanywanyi, Abdunoor M.; Katana, Abraham; Maculuve, Sonia; Mayor, Alfredo; Nhacolo, Arsenio; Otieno, Kephas; Pahlavan, Golbahar; Rupérez, María; Sevene, Esperança; Slutsker, Laurence; Vala, Anifa; Williamsom, John; Menéndez, Clara

2014-01-01

Background Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for malaria prevention in HIV-negative pregnant women, but it is contraindicated in HIV-infected women taking daily cotrimoxazole prophylaxis (CTXp) because of potential added risk of adverse effects associated with taking two antifolate drugs simultaneously. We studied the safety and efficacy of mefloquine (MQ) in women receiving CTXp and long-lasting insecticide treated nets (LLITNs). Methods and Findings A total of 1,071 HIV-infected women from Kenya, Mozambique, and Tanzania were randomized to receive either three doses of IPTp-MQ (15 mg/kg) or placebo given at least one month apart; all received CTXp and a LLITN. IPTp-MQ was associated with reduced rates of maternal parasitemia (risk ratio [RR], 0.47 [95% CI 0.27–0.82]; p = 0.008), placental malaria (RR, 0.52 [95% CI 0.29–0.90]; p = 0.021), and reduced incidence of non-obstetric hospital admissions (RR, 0.59 [95% CI 0.37–0.95]; p = 0.031) in the intention to treat (ITT) analysis. There were no differences in the prevalence of adverse pregnancy outcomes between groups. Drug tolerability was poorer in the MQ group compared to the control group (29.6% referred dizziness and 23.9% vomiting after the first IPTp-MQ administration). HIV viral load at delivery was higher in the MQ group compared to the control group (p = 0.048) in the ATP analysis. The frequency of perinatal mother to child transmission of HIV was increased in women who received MQ (RR, 1.95 [95% CI 1.14–3.33]; p = 0.015). The main limitation of the latter finding relates to the exploratory nature of this part of the analysis. Conclusions An effective antimalarial added to CTXp and LLITNs in HIV-infected pregnant women can improve malaria prevention, as well as maternal health through reduction in hospital admissions. However, MQ was not well tolerated, limiting its potential for IPTp and indicating the need to find alternatives with better tolerability to reduce malaria in this particularly vulnerable group. MQ was associated with an increased risk of mother to child transmission of HIV, which warrants a better understanding of the pharmacological interactions between antimalarials and antiretroviral drugs. Trial registration ClinicalTrials.gov NCT 00811421; Pan African Clinical Trials Registry PACTR 2010020001813440 Please see later in the article for the Editors' Summary PMID:25247995

Intermittent preventive treatment of malaria in pregnancy with mefloquine in HIV-infected women receiving cotrimoxazole prophylaxis: a multicenter randomized placebo-controlled trial.

PubMed

González, Raquel; Desai, Meghna; Macete, Eusebio; Ouma, Peter; Kakolwa, Mwaka A; Abdulla, Salim; Aponte, John J; Bulo, Helder; Kabanywanyi, Abdunoor M; Katana, Abraham; Maculuve, Sonia; Mayor, Alfredo; Nhacolo, Arsenio; Otieno, Kephas; Pahlavan, Golbahar; Rupérez, María; Sevene, Esperança; Slutsker, Laurence; Vala, Anifa; Williamsom, John; Menéndez, Clara

2014-09-01

Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for malaria prevention in HIV-negative pregnant women, but it is contraindicated in HIV-infected women taking daily cotrimoxazole prophylaxis (CTXp) because of potential added risk of adverse effects associated with taking two antifolate drugs simultaneously. We studied the safety and efficacy of mefloquine (MQ) in women receiving CTXp and long-lasting insecticide treated nets (LLITNs). A total of 1,071 HIV-infected women from Kenya, Mozambique, and Tanzania were randomized to receive either three doses of IPTp-MQ (15 mg/kg) or placebo given at least one month apart; all received CTXp and a LLITN. IPTp-MQ was associated with reduced rates of maternal parasitemia (risk ratio [RR], 0.47 [95% CI 0.27-0.82]; p=0.008), placental malaria (RR, 0.52 [95% CI 0.29-0.90]; p=0.021), and reduced incidence of non-obstetric hospital admissions (RR, 0.59 [95% CI 0.37-0.95]; p=0.031) in the intention to treat (ITT) analysis. There were no differences in the prevalence of adverse pregnancy outcomes between groups. Drug tolerability was poorer in the MQ group compared to the control group (29.6% referred dizziness and 23.9% vomiting after the first IPTp-MQ administration). HIV viral load at delivery was higher in the MQ group compared to the control group (p=0.048) in the ATP analysis. The frequency of perinatal mother to child transmission of HIV was increased in women who received MQ (RR, 1.95 [95% CI 1.14-3.33]; p=0.015). The main limitation of the latter finding relates to the exploratory nature of this part of the analysis. An effective antimalarial added to CTXp and LLITNs in HIV-infected pregnant women can improve malaria prevention, as well as maternal health through reduction in hospital admissions. However, MQ was not well tolerated, limiting its potential for IPTp and indicating the need to find alternatives with better tolerability to reduce malaria in this particularly vulnerable group. MQ was associated with an increased risk of mother to child transmission of HIV, which warrants a better understanding of the pharmacological interactions between antimalarials and antiretroviral drugs. ClinicalTrials.gov NCT 00811421; Pan African Clinical Trials Registry PACTR 2010020001813440 Please see later in the article for the Editors' Summary.

NEO PI-R Normative Personality Data that Distinguish U.S. Air Force MQ-1 Predator and MQ-9 Reaper Sensor Operators from AC-130 Gunship Sensor Operators and Peers in the General Population

DTIC Science & Technology

2011-06-30

Subscale Scores for MQ-1 Predator (n=56) and AC-130 Gunship (n=59) SOs (◊ = mean, — = median, □ = ±1 SD; TRUST = Trusting , STRAI=Straightforwardness...others have reported Predator/Reaper SOs to be more interpersonally warm, gregarious, and trusting , as well as more imaginative. It is difficult...entertain novel ideas and unconventional values; (d) Agreeableness – general interpersonal tendencies regarding altruism, trust

Efficacy of Artesunate-mefloquine for Chloroquine-resistant Plasmodium vivax Malaria in Malaysia: An Open-label, Randomized, Controlled Trial

PubMed Central

Grigg, Matthew J.; William, Timothy; Menon, Jayaram; Barber, Bridget E.; Wilkes, Christopher S.; Rajahram, Giri S.; Edstein, Michael D.; Auburn, Sarah; Price, Ric N.; Yeo, Tsin W.; Anstey, Nicholas M.

2016-01-01

Background. Chloroquine (CQ)-resistant Plasmodium vivax is increasingly reported throughout southeast Asia. The efficacy of CQ and alternative artemisinin combination therapies (ACTs) for vivax malaria in Malaysia is unknown. Methods. A randomized, controlled trial of CQ vs artesunate-mefloquine (AS-MQ) for uncomplicated vivax malaria was conducted in 3 district hospitals in Sabah, Malaysia. Primaquine was administered on day 28. The primary outcome was the cumulative risk of treatment failure by day 28 by Kaplan–Meier analysis. Results. From 2012 to 2014, 103 adults and children were enrolled. Treatment failure by day 28 was 61.1% (95% confidence interval [CI], 46.8–75.6) after CQ and 0% (95% CI, 0–.08) following AS-MQ (P < .001), of which 8.2% (95% CI, 2.5–9.6) were early treatment failures. All patients with treatment failure had therapeutic plasma CQ concentrations at day 7. Compared with CQ, AS-MQ was associated with faster parasite clearance (normalized clearance slope, 0.311 vs 0.127; P < .001) and fever clearance (mean, 19.0 vs 37.7 hours; P = .001) and with lower risk of anemia at day 28 (odds ratio = 3.7; 95% CI, 1.5–9.3; P = .005). Gametocytes were present at day 28 in 23.8% (10/42) of patients following CQ vs none with AS-MQ (P < .001). AS-MQ resulted in lower bed occupancy: 4037 vs 6510 days/1000 patients (incidence rate ratio 0.62; 95% CI, .60–.65; P < .001). One patient developed severe anemia not regarded as related to their AS-MQ treatment. Conclusions. High-grade CQ-resistant P. vivax is prevalent in eastern Malaysia. AS-MQ is an efficacious ACT for all malaria species. Wider CQ-efficacy surveillance is needed in vivax-endemic regions with earlier replacement with ACT when treatment failure is detected. Clinical Trials Registration. NCT01708876. PMID:27107287

Efficacy of Artesunate-mefloquine for Chloroquine-resistant Plasmodium vivax Malaria in Malaysia: An Open-label, Randomized, Controlled Trial.

PubMed

Grigg, Matthew J; William, Timothy; Menon, Jayaram; Barber, Bridget E; Wilkes, Christopher S; Rajahram, Giri S; Edstein, Michael D; Auburn, Sarah; Price, Ric N; Yeo, Tsin W; Anstey, Nicholas M

2016-06-01

Chloroquine (CQ)-resistant Plasmodium vivax is increasingly reported throughout southeast Asia. The efficacy of CQ and alternative artemisinin combination therapies (ACTs) for vivax malaria in Malaysia is unknown. A randomized, controlled trial of CQ vs artesunate-mefloquine (AS-MQ) for uncomplicated vivax malaria was conducted in 3 district hospitals in Sabah, Malaysia. Primaquine was administered on day 28. The primary outcome was the cumulative risk of treatment failure by day 28 by Kaplan-Meier analysis. From 2012 to 2014, 103 adults and children were enrolled. Treatment failure by day 28 was 61.1% (95% confidence interval [CI], 46.8-75.6) after CQ and 0% (95% CI, 0-.08) following AS-MQ (P < .001), of which 8.2% (95% CI, 2.5-9.6) were early treatment failures. All patients with treatment failure had therapeutic plasma CQ concentrations at day 7. Compared with CQ, AS-MQ was associated with faster parasite clearance (normalized clearance slope, 0.311 vs 0.127; P < .001) and fever clearance (mean, 19.0 vs 37.7 hours; P =001) and with lower risk of anemia at day 28 (odds ratio = 3.7; 95% CI, 1.5-9.3; P =005). Gametocytes were present at day 28 in 23.8% (10/42) of patients following CQ vs none with AS-MQ (P < .001). AS-MQ resulted in lower bed occupancy: 4037 vs 6510 days/1000 patients (incidence rate ratio 0.62; 95% CI, .60-.65; P < .001). One patient developed severe anemia not regarded as related to their AS-MQ treatment. High-grade CQ-resistant P. vivax is prevalent in eastern Malaysia. AS-MQ is an efficacious ACT for all malaria species. Wider CQ-efficacy surveillance is needed in vivax-endemic regions with earlier replacement with ACT when treatment failure is detected.Clinical Trials Registration NCT01708876. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

A novel insulin resistance index to monitor changes in insulin sensitivity and glucose tolerance: the ACT NOW study.

PubMed

Tripathy, Devjit; Cobb, Jeff E; Gall, Walter; Adam, Klaus-Peter; George, Tabitha; Schwenke, Dawn C; Banerji, MaryAnn; Bray, George A; Buchanan, Thomas A; Clement, Stephen C; Henry, Robert R; Kitabchi, Abbas E; Mudaliar, Sunder; Ratner, Robert E; Stentz, Frankie B; Reaven, Peter D; Musi, Nicolas; Ferrannini, Ele; DeFronzo, Ralph A

2015-05-01

The objective was to test the clinical utility of Quantose M(Q) to monitor changes in insulin sensitivity after pioglitazone therapy in prediabetic subjects. Quantose M(Q) is derived from fasting measurements of insulin, α-hydroxybutyrate, linoleoyl-glycerophosphocholine, and oleate, three nonglucose metabolites shown to correlate with insulin-stimulated glucose disposal. Participants were 428 of the total of 602 ACT NOW impaired glucose tolerance (IGT) subjects randomized to pioglitazone (45 mg/d) or placebo and followed for 2.4 years. At baseline and study end, fasting plasma metabolites required for determination of Quantose, glycated hemoglobin, and oral glucose tolerance test with frequent plasma insulin and glucose measurements to calculate the Matsuda index of insulin sensitivity were obtained. Pioglitazone treatment lowered IGT conversion to diabetes (hazard ratio = 0.25; 95% confidence interval = 0.13-0.50; P < .0001). Although glycated hemoglobin did not track with insulin sensitivity, Quantose M(Q) increased in pioglitazone-treated subjects (by 1.45 [3.45] mg·min(-1)·kgwbm(-1)) (median [interquartile range]) (P < .001 vs placebo), as did the Matsuda index (by 3.05 [4.77] units; P < .0001). Quantose M(Q) correlated with the Matsuda index at baseline and change in the Matsuda index from baseline (rho, 0.85 and 0.79, respectively; P < .0001) and was progressively higher across closeout glucose tolerance status (diabetes, IGT, normal glucose tolerance). In logistic models including only anthropometric and fasting measurements, Quantose M(Q) outperformed both Matsuda and fasting insulin in predicting incident diabetes. In IGT subjects, Quantose M(Q) parallels changes in insulin sensitivity and glucose tolerance with pioglitazone therapy. Due to its strong correlation with improved insulin sensitivity and its ease of use, Quantose M(Q) may serve as a useful clinical test to identify and monitor therapy in insulin-resistant patients.

A Novel Insulin Resistance Index to Monitor Changes in Insulin Sensitivity and Glucose Tolerance: the ACT NOW Study

PubMed Central

Tripathy, Devjit; Cobb, Jeff E.; Gall, Walter; Adam, Klaus-Peter; George, Tabitha; Schwenke, Dawn C.; Banerji, MaryAnn; Bray, George A.; Buchanan, Thomas A.; Clement, Stephen C.; Henry, Robert R.; Kitabchi, Abbas E.; Mudaliar, Sunder; Ratner, Robert E.; Stentz, Frankie B.; Reaven, Peter D.; Musi, Nicolas; Ferrannini, Ele

2015-01-01

Objective: The objective was to test the clinical utility of Quantose MQ to monitor changes in insulin sensitivity after pioglitazone therapy in prediabetic subjects. Quantose MQ is derived from fasting measurements of insulin, α-hydroxybutyrate, linoleoyl-glycerophosphocholine, and oleate, three nonglucose metabolites shown to correlate with insulin-stimulated glucose disposal. Research Design and Methods: Participants were 428 of the total of 602 ACT NOW impaired glucose tolerance (IGT) subjects randomized to pioglitazone (45 mg/d) or placebo and followed for 2.4 years. At baseline and study end, fasting plasma metabolites required for determination of Quantose, glycated hemoglobin, and oral glucose tolerance test with frequent plasma insulin and glucose measurements to calculate the Matsuda index of insulin sensitivity were obtained. Results: Pioglitazone treatment lowered IGT conversion to diabetes (hazard ratio = 0.25; 95% confidence interval = 0.13–0.50; P < .0001). Although glycated hemoglobin did not track with insulin sensitivity, Quantose MQ increased in pioglitazone-treated subjects (by 1.45 [3.45] mg·min−1·kgwbm−1) (median [interquartile range]) (P < .001 vs placebo), as did the Matsuda index (by 3.05 [4.77] units; P < .0001). Quantose MQ correlated with the Matsuda index at baseline and change in the Matsuda index from baseline (rho, 0.85 and 0.79, respectively; P < .0001) and was progressively higher across closeout glucose tolerance status (diabetes, IGT, normal glucose tolerance). In logistic models including only anthropometric and fasting measurements, Quantose MQ outperformed both Matsuda and fasting insulin in predicting incident diabetes. Conclusions: In IGT subjects, Quantose MQ parallels changes in insulin sensitivity and glucose tolerance with pioglitazone therapy. Due to its strong correlation with improved insulin sensitivity and its ease of use, Quantose MQ may serve as a useful clinical test to identify and monitor therapy in insulin-resistant patients. PMID:25603459

Tolerability of mefloquine intermittent preventive treatment for malaria in HIV-infected pregnant women in Benin.

PubMed

Denoeud-Ndam, Lise; Clément, Marie-Caroline; Briand, Valérie; Akakpo, Jocelyn; Agossou, Videhouenou K; Atadokpédé, Félix; Dossou-Gbété, Lucien; Komongui, Didier G; Afangnihoun, Aldric; Girard, Pierre-Marie; Zannou, Djimon-Marcel; Cot, Michel

2012-09-01

To investigate the tolerability of mefloquine intermittent preventive treatment (MQ IPTp) for malaria in HIV-infected pregnant women compared with HIV-negative women. Prospective cohort study comparing samples of HIV-negative and HIV-infected pregnant women from 2 clinical trials conducted in Benin. One hundred and three HIV-infected women from the ongoing PACOME trial were compared with 421 HIV-negative women from a former trial, both trials aiming to evaluate the efficacy and tolerability of MQ IPTp, administered at the dose of 15 mg/kg. Descriptive analysis compared the proportion of women reporting at least 1 adverse reaction, according to HIV status. Multilevel logistic regression identified factors associated with the probability of reporting an adverse reaction for each MQ intake. Dizziness and vomiting were the most frequent adverse reactions. Adverse reactions were less frequent in HIV-infected women (65% versus 78%, P = 0.009). In multilevel analysis, HIV infection [odds ratio (OR) = 0.23, 95% confidence interval (CI) = 0.08 to 0.61] decreased the risk for adverse reactions, whereas detectable viral load (OR = 2.46, 95% CI = 1.07 to 5.66), first intake (versus further intakes, OR = 5.26, 95% CI = 3.70 to 7.14), older age (OR = 1.62, 95% CI = 1.13 to 2.32), and higher education level (OR = 1.71, 95% CI = 1.12 to 2.61) increased the risk. Moderate and severe adverse reactions were more frequent when antiretrovirals were started concomitantly with a MQ intake. This study provides reassuring data on the use of MQ IPTp in HIV-infected pregnant women. However frequent, adverse reactions remained moderate and did not impair adherence to MQ IPTp. In this high-risk group, MQ might be an acceptable alternative in case sulfadoxine-pyrimethamine loses its efficacy for intermittent preventive treatment.

Improving Block-level Efficiency with scsi-mq

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

Caldwell, Blake A

2015-01-01

Current generation solid-state storage devices are exposing a new bottlenecks in the SCSI and block layers of the Linux kernel, where IO throughput is limited by lock contention, inefficient interrupt handling, and poor memory locality. To address these limitations, the Linux kernel block layer underwent a major rewrite with the blk-mq project to move from a single request queue to a multi-queue model. The Linux SCSI subsystem rework to make use of this new model, known as scsi-mq, has been merged into the Linux kernel and work is underway for dm-multipath support in the upcoming Linux 4.0 kernel. These piecesmore » were necessary to make use of the multi-queue block layer in a Lustre parallel filesystem with high availability requirements. We undertook adding support of the 3.18 kernel to Lustre with scsi-mq and dm-multipath patches to evaluate the potential of these efficiency improvements. In this paper we evaluate the block-level performance of scsi-mq with backing storage hardware representative of a HPC-targerted Lustre filesystem. Our findings show that SCSI write request latency is reduced by as much as 13.6%. Additionally, when profiling the CPU usage of our prototype Lustre filesystem, we found that CPU idle time increased by a factor of 7 with Linux 3.18 and blk-mq as compared to a standard 2.6.32 Linux kernel. Our findings demonstrate increased efficiency of the multi-queue block layer even with disk-based caching storage arrays used in existing parallel filesystems.« less

Multiplex Quantitative PCR Assays for the Detection and Quantification of the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces.

PubMed

Shridhar, P B; Noll, L W; Shi, X; An, B; Cernicchiaro, N; Renter, D G; Nagaraja, T G; Bai, J

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, called non-O157 STEC, are important foodborne pathogens. Cattle, a major reservoir, harbor the organisms in the hindgut and shed them in the feces. Although limited data exist on fecal shedding, concentrations of non-O157 STEC in feces have not been reported. The objectives of our study were (i) to develop and validate two multiplex quantitative PCR (mqPCR) assays, targeting O-antigen genes of O26, O103, and O111 (mqPCR-1) and O45, O121, and O145 (mqPCR-2); (ii) to utilize the two assays, together with a previously developed four-plex qPCR assay (mqPCR-3) targeting the O157 antigen and three virulence genes (stx1, stx2, and eae), to quantify seven serogroups and three virulence genes in cattle feces; and (iii) to compare the three mqPCR assays to a 10-plex conventional PCR (cPCR) targeting seven serogroups and three virulence genes and culture methods to detect seven E. coli serogroups in cattle feces. The two mqPCR assays (1 and 2) were shown to be specific to the target genes, and the detection limits were 4 and 2 log CFU/g of pure culture-spiked fecal samples, before and after enrichment, respectively. A total of 576 fecal samples collected from a feedlot were enriched in E. coli broth and were subjected to quantification (before enrichment) and detection (after enrichment). Of the 576 fecal samples subjected, before enrichment, to three mqPCR assays for quantification, 175 (30.4%) were quantifiable (≥4 log CFU/g) for at least one of the seven serogroups, with O157 being the most common serogroup. The three mqPCR assays detected higher proportions of postenriched fecal samples (P > 0.01) as positive for one or more serogroups compared with cPCR and culture methods. This is the first study to assess the applicability of qPCR assays to detect and quantify six non-O157 serogroups in cattle feces and to generate data on fecal concentration of the six serogroups.

Quantum Attack-Resistent Certificateless Multi-Receiver Signcryption Scheme

PubMed Central

Li, Huixian; Chen, Xubao; Pang, Liaojun; Shi, Weisong

2013-01-01

The existing certificateless signcryption schemes were designed mainly based on the traditional public key cryptography, in which the security relies on the hard problems, such as factor decomposition and discrete logarithm. However, these problems will be easily solved by the quantum computing. So the existing certificateless signcryption schemes are vulnerable to the quantum attack. Multivariate public key cryptography (MPKC), which can resist the quantum attack, is one of the alternative solutions to guarantee the security of communications in the post-quantum age. Motivated by these concerns, we proposed a new construction of the certificateless multi-receiver signcryption scheme (CLMSC) based on MPKC. The new scheme inherits the security of MPKC, which can withstand the quantum attack. Multivariate quadratic polynomial operations, which have lower computation complexity than bilinear pairing operations, are employed in signcrypting a message for a certain number of receivers in our scheme. Security analysis shows that our scheme is a secure MPKC-based scheme. We proved its security under the hardness of the Multivariate Quadratic (MQ) problem and its unforgeability under the Isomorphism of Polynomials (IP) assumption in the random oracle model. The analysis results show that our scheme also has the security properties of non-repudiation, perfect forward secrecy, perfect backward secrecy and public verifiability. Compared with the existing schemes in terms of computation complexity and ciphertext length, our scheme is more efficient, which makes it suitable for terminals with low computation capacity like smart cards. PMID:23967037

Effective stimulation of the biotechnological potential of the medicinal white rot fungus: Phellinus pini by menadione-mediated oxidative stress.

PubMed

Jaszek, Magdalena; Kos, Katarzyna; Matuszewska, Anna; Grąz, Marcin; Stefaniuk, Dawid; Osińska-Jaroszuk, Monika; Prendecka, Monika; Jóźwik, Ewa; Grzywnowicz, Krzysztof

2014-09-01

The effect of menadione (MQ; 2-methyl-1,4-naphtoquinone), a superoxide-generating agent, on the natural biodegradation system in the medicinal white rot fungus Phellinus pini was determined. While measuring the activities of extracellular manganese-dependent peroxidase (MnP) and intracellular chitinase, it was found that the application of MQ (0.75 mM) distinctly stimulated the activities of these enzymes in comparison to the control values (without MQ). Using the capillary electrophoresis (CE) method, an increase in the extracellular oxalic acid (OXA) concentration was detected during the first days after the addition of MQ. It was observed that the rate of intracellular proteolysis at pH 3.5 evidently decreased under oxidative stress conditions. Contrary to these results, the activities of serine proteases at pH 9.5 measured against fluorogenic peptide substrates distinctly increased in stressed cultures. The MQ treatment also caused an evident increase in the catalase (CAT) activity, as well as the levels of superoxide anion radicals (SORs), formaldehyde (FA), and phenolic compounds (PHC) in the experimental cultures. The results obtained confirm that prooxidants may find application as an effective way to stimulate biotechnological production of MnP and chitinase by white rot fungi.

Understanding M-ligand bonding and mer-/fac-isomerism in tris(8-hydroxyquinolinate) metallic complexes.

PubMed

Lima, Carlos F R A C; Taveira, Ricardo J S; Costa, José C S; Fernandes, Ana M; Melo, André; Silva, Artur M S; Santos, Luís M N B F

2016-06-28

Tris(8-hydroxyquinolinate) metallic complexes, Mq3, are one of the most important classes of organic semiconductor materials. Herein, the nature of the chemical bond in Mq3 complexes and its implications on their molecular properties were investigated by a combined experimental and computational approach. Various Mq3 complexes, resulting from the alteration of the metal and substitution of the 8-hydroxyquinoline ligand in different positions, were prepared. The mer-/fac-isomerism in Mq3 was explored by FTIR and NMR spectroscopy, evidencing that, irrespective of the substituent, mer- and fac-are the most stable molecular configurations of Al(iii) and In(iii) complexes, respectively. The relative M-ligand bond dissociation energies were evaluated experimentally by electrospray ionization tandem mass spectrometry (ESI-MS-MS), showing a non-monotonous variation along the group (Al > In > Ga). The results reveal a strong covalent character in M-ligand bonding, which allows for through-ligand electron delocalization, and explain the preferred molecular structures of Mq3 complexes as resulting from the interplay between bonding and steric factors. The mer-isomer reduces intraligand repulsions, being preferred for smaller metals, while the fac-isomer is favoured for larger metals where stronger covalent M-ligand bonds can be formed due to more extensive through-ligand conjugation mediated by metal "d" orbitals.

Pentocin MQ1: A Novel, Broad-Spectrum, Pore-Forming Bacteriocin From Lactobacillus pentosus CS2 With Quorum Sensing Regulatory Mechanism and Biopreservative Potential

PubMed Central

Wayah, Samson B.; Philip, Koshy

2018-01-01

Micrococcus luteus, Listeria monocytogenes, and Bacillus cereus are major food-borne pathogenic and spoilage bacteria. Emergence of antibiotic resistance and consumer demand for foods containing less of chemical preservatives led to a search for natural antimicrobials. A study aimed at characterizing, investigating the mechanism of action and regulation of biosynthesis and evaluating the biopreservative potential of pentocin from Lactobacillus pentosus CS2 was conducted. Pentocin MQ1 is a novel bacteriocin isolated from L. pentosus CS2 of coconut shake origin. The purification strategy involved adsorption-desorption of bacteriocin followed by RP-HPLC. It has a molecular weight of 2110.672 Da as determined by MALDI-TOF mass spectrometry and a molar extinction value of 298.82 M−1 cm−1. Pentocin MQ1 is not plasmid-borne and its biosynthesis is regulated by a quorum sensing mechanism. It has a broad spectrum of antibacterial activity, exhibited high chemical, thermal and pH stability but proved sensitive to proteolytic enzymes. It is potent against M. luteus, B. cereus, and L. monocytogenes at micromolar concentrations. It is quick-acting and exhibited a bactericidal mode of action against its targets. Target killing was mediated by pore formation. We report for the first time membrane permeabilization as a mechanism of action of the pentocin from the study against Gram-positive bacteria. Pentocin MQ1 is a cell wall-associated bacteriocin. Application of pentocin MQ1 improved the microbiological quality and extended the shelf life of fresh banana. This is the first report on the biopreservation of banana using bacteriocin. These findings place pentocin MQ1 as a potential biopreservative for further evaluation in food and medical applications. PMID:29636737

Nanowires of metal (Cd, Cu) halide complexes with 8-hydroxyquinoline for photoelectrochemical and electrochemiluminescence sensing

NASA Astrophysics Data System (ADS)

Huang, Shan; Pang, Guangming; Li, Xiangkui; Li, Jianping; Pan, Hongcheng

2017-12-01

Metal-hydroxyquinoline-halogen (MqX, M = Cd, Cu; q = 8-hydroxyquinoline; X = Cl, Br, I) nanowires are synthesized via a sonochemical-assisted method. The elemental analysis (EA), inductively coupled plasma-optical emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS) support an M/q/X ratio of 1:1:1. The electron microscope images reveal a typical CdqX and CuqX nanowire diameter of 30-50 nm and a nanowire length of 400-600 nm. In addition, the synthesis of the MqX nanowires is only observed when there is an excess of halide ions (X/q molar ratio of 3 or greater). This halide deficiency results in the formation of micrometer-sized Mq2 sheets. We demonstrated the conversion of the MqX nanowires to Mq2 micro-sheets in an ultrasonic bath of 1 M 8-Hq ethanol solutions (50%, w/ w) at 50 °C for 2 h, but not vice versa. The MqX nanowires exhibited excellent properties for photoluminescence, electrochemiluminescence (ECL), and photoelectrochemistry (PEC). The CdqBr and CdqI nanowires were coated onto a glass carbon and a fluorine-doped tin oxide glass electrode to develop the above ECL and PEC methods for the detection of H2O2 and Cu2+, respectively. In the range of 2 to 14 μM, the ECL intensity of the CdqBr nanowires was inversely proportional to the concentration of H2O2 with a detection limit of 0.26 μM. For Cu2+ sensing, the photocurrent of the CdqI nanowires exhibited a linear response to Cu2+ over the range of 2 to 16 μM of which a detection limit of 0.2 μM was observed.

Body mass index and motor coordination: Non-linear relationships in children 6-10 years.

PubMed

Lopes, V P; Malina, R M; Maia, J A R; Rodrigues, L P

2018-05-01

Given the concern for health-related consequences of an elevated body mass index (BMI; obesity), the potential consequences of a low BMI in children are often overlooked. The purpose was to evaluate the relationship between the BMI across its entire spectrum and motor coordination (MC) in children 6-10 years. Height, weight, and MC (Körperkoordinationstest für Kinder, KTK test battery) were measured in 1,912 boys and 1,826 girls of 6-10 years of age. BMI (kg/m 2 ) was calculated. KTK scores for each of the four tests were also converted to a motor quotient (MQ). One-way ANOVA was used to test differences in the BMI, individual test items, and MQ among boys and girls within age groups. Sex-specific quadratic regressions of individual KTK items and the MQ on the BMI were calculated. Girls and boys were also classified into four weight status groups using International Obesity Task Force criteria: thin, normal, overweight, and obese. Differences in specific test items and MQ between weight status groups were evaluated by age group in each sex. Thirty-one percent of the sample was overweight or obese, whereas 5% was thin. On average, normal weight children had the highest MQ in both sexes across the age range with few exceptions. Overweight/obese children had a lower MQ than normal weight and thin children. The quadratic regression lines generally presented an inverted parabolic relationship between the BMI and MC and suggested a decrease in MC with an increase in the BMI. In general, BMI shows a curvilinear, inverted parabolic relationship with MC in children 6-10 years. © 2018 John Wiley & Sons Ltd.

Mortality, Morbidity, and Developmental Outcomes in Infants Born to Women Who Received Either Mefloquine or Sulfadoxine-Pyrimethamine as Intermittent Preventive Treatment of Malaria in Pregnancy: A Cohort Study

PubMed Central

Rupérez, María; González, Raquel; Mombo-Ngoma, Ghyslain; Kabanywanyi, Abdunoor M.; Sevene, Esperança; Ouédraogo, Smaïla; Kakolwa, Mwaka A.; Vala, Anifa; Accrombessi, Manfred; Briand, Valérie; Aponte, John J.; Manego Zoleko, Rella; Adegnika, Ayôla A.; Cot, Michel; Kremsner, Peter G.; Massougbodji, Achille; Abdulla, Salim; Ramharter, Michael; Macete, Eusébio; Menéndez, Clara

2016-01-01

Background Little is known about the effects of intermittent preventive treatment of malaria in pregnancy (IPTp) on the health of sub-Saharan African infants. We have evaluated the safety of IPTp with mefloquine (MQ) compared to sulfadoxine-pyrimethamine (SP) for important infant health and developmental outcomes. Methods and Findings In the context of a multicenter randomized controlled trial evaluating the safety and efficacy of IPTp with MQ compared to SP in pregnancy carried out in four sub-Saharan countries (Mozambique, Benin, Gabon, and Tanzania), 4,247 newborns, 2,815 born to women who received MQ and 1,432 born to women who received SP for IPTp, were followed up until 12 mo of age. Anthropometric parameters and psychomotor development were assessed at 1, 9, and 12 mo of age, and the incidence of malaria, anemia, hospital admissions, outpatient visits, and mortality were determined until 12 mo of age. No significant differences were found in the proportion of infants with stunting, underweight, wasting, and severe acute malnutrition at 1, 9, and 12 mo of age between infants born to women who were on IPTp with MQ versus SP. Except for three items evaluated at 9 mo of age, no significant differences were observed in the psychomotor development milestones assessed. Incidence of malaria, anemia, hospital admissions, outpatient visits, and mortality were similar between the two groups. Information on the outcomes at 12 mo of age was unavailable in 26% of the infants, 761 (27%) from the MQ group and 377 (26%) from the SP group. Reasons for not completing the study were death (4% of total study population), study withdrawal (6%), migration (8%), and loss to follow-up (9%). Conclusions No significant differences were found between IPTp with MQ and SP administered in pregnancy on infant mortality, morbidity, and nutritional outcomes. The poorer performance on certain psychomotor development milestones at 9 mo of age in children born to women in the MQ group compared to those in the SP group may deserve further studies. Trial registration ClinicalTrials.gov NCT00811421 PMID:26905278

Magnetic Field Effect: An Efficient Tool To Investigate The Mechanism Of Reactions Using Laser Flash Photolysis Technique

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

Basu, Samita; Bose, Adity; Dey, Debarati

2008-04-24

Magnetic field effect combined with laser flash photolysis technique have been used to study the mechanism of interactions between two drug-like quinone molecules, Menadione (1,4-naphthoquinone, MQ) and 9, 10 Anthraquinone (AQ) with one of the DNA bases, Adenine in homogeneous acetonitrile/water and heterogeneous micellar media. A switchover in reaction mode from electron transfer to hydrogen abstraction is observed with MQ on changing the solvent from acetonitrile/water to micelle; whereas, AQ retains its mode of interaction towards Adenine as electron transfer in both the media due to its bulky structure compared to MQ.

Magnetic Field Effect: An Efficient Tool To Investigate The Mechanism Of Reactions Using Laser Flash Photolysis Technique

NASA Astrophysics Data System (ADS)

Basu, Samita; Bose, Adity; Dey, Debarati

2008-04-01

Magnetic field effect combined with laser flash photolysis technique have been used to study the mechanism of interactions between two drug-like quinone molecules, Menadione (1,4-naphthoquinone, MQ) and 9, 10 Anthraquinone (AQ) with one of the DNA bases, Adenine in homogeneous acetonitrile/water and heterogeneous micellar media. A switchover in reaction mode from electron transfer to hydrogen abstraction is observed with MQ on changing the solvent from acetonitrile/water to micelle; whereas, AQ retains its mode of interaction towards Adenine as electron transfer in both the media due to its bulky structure compared to MQ.

An Air Force Strategy for the Long Haul

DTIC Science & Technology

2009-01-01

neuver ( MVM ) that suggests a very heavy vertical takeoff and landing (VTOL) plat- form. It is clear from a recent Defense Science Board (DSB...refueling tanker) KC-X Future aerial refueling tanker LEO Low earth orbit MQ-1 Predator (unmanned aerial vehicle) MQ-9 Reaper (unmanned aerial vehicle) MVM

Spinterface between tris(8-hydroxyquinoline)metal(III) molecules and magnetic surfaces: a first-principles study

NASA Astrophysics Data System (ADS)

Jiang, W.; Wang, Jingying; Dougherty, Daniel; Liu, Feng; Feng Liu Team; Daniel Dougherty Team

Using first-principles calculations, we have systematically investigated the hybridization between tris(8-hydroxyquinoline)metal(III) (Mq3, M = Fe, Cr, Al) molecules and magnetic substrates (Co and Cr). Mq3 with different central metal elements but the same organic framework has dramatically different interaction with different magnetic substrates, which affect the interface state significantly. AFM coupling was observed between magnetic Mq3 molecules and ferromagnetic (Co) as well as antiferromagnetic (Cr) substrate, manifested with a superexchange and direct exchange interaction, respectively. Such strong magnetic interfacial coupling may open a gap around the Fermi level and significantly change interface transport properties. Nonmagnetic Alq3 molecule was found to enhance the interface spin polarization due to hybridization between the lowest unoccupied molecular orbitals (LUMO) of Alq3 and metallic surface state. These findings will help better understand spinterface and shed new light on future application of Mq3 molecules in spintronics devices. This work was support by NSF-MRSEC (DMR-1121252) and DOE-BES (DE-FG02-04ER46148).

Optimal designs based on the maximum quasi-likelihood estimator

PubMed Central

Shen, Gang; Hyun, Seung Won; Wong, Weng Kee

2016-01-01

We use optimal design theory and construct locally optimal designs based on the maximum quasi-likelihood estimator (MqLE), which is derived under less stringent conditions than those required for the MLE method. We show that the proposed locally optimal designs are asymptotically as efficient as those based on the MLE when the error distribution is from an exponential family, and they perform just as well or better than optimal designs based on any other asymptotically linear unbiased estimators such as the least square estimator (LSE). In addition, we show current algorithms for finding optimal designs can be directly used to find optimal designs based on the MqLE. As an illustrative application, we construct a variety of locally optimal designs based on the MqLE for the 4-parameter logistic (4PL) model and study their robustness properties to misspecifications in the model using asymptotic relative efficiency. The results suggest that optimal designs based on the MqLE can be easily generated and they are quite robust to mis-specification in the probability distribution of the responses. PMID:28163359

Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

NASA Technical Reports Server (NTRS)

Bendrick, Gregg A.; Kamine, Tovy Haber

2008-01-01

Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. "cones") of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement" (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Methods: Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. Results: The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of "Maximum Eye Movement". However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of "Easy Eye Movement", though all were within the cone of "Maximum Eye Movement". All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Discussion: Most instrument displays in conventional aircraft lay within the cone of "Easy Eye Movement", though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight.

Spectroscopic observations of ATLAS17lcs (SN 2017guv) and ASASSN-17mq (AT 2017gvo) by NUTS (NOT Un-biased Transient Survey)

NASA Astrophysics Data System (ADS)

Dong, Subo; Bose, Subhash; Stritzinger, M.; Holmbo, S.; Fraser, M.; Fedorets, G.

2017-10-01

The Nordic Optical Telescope (NOT) Unbiased Transient Survey (NUTS; ATel #8992) reports the spectroscopic classification of ATLAS17lcs (SN 2017guv) and ASASSN-17mq (AT 2017gvo) in host galaxies 2MASX J19132225-1648031 and CGCG 225-050, respectively.

FairMQ for Online Reconstruction - An example on \\overline{{\\rm{P}}}ANDA test beam data

NASA Astrophysics Data System (ADS)

Stockmanns, Tobias; PANDA Collaboration

2017-10-01

One of the large challenges of future particle physics experiments is the trend to run without a first level hardware trigger. The typical data rates exceed easily hundreds of GBytes/s, which is way too much to be stored permanently for an offline analysis. Therefore a strong data reduction has to be done by selection of only those data, which are physically interesting. This implies that all detector data are read out and have to be processed with the same rate as it is produced. Several different hardware approaches from FPGAs, GPUs to multicore CPUs and mixtures of these systems are under study. Common to all of them is the need to process the data in massive parallel systems. One very convenient way to realize parallel systems on heterogeneous systems is the usage of message queue based multiprocessing. One package that allow development of such application is the FairMQ module in the FairRoot simulation framework developed at GSI. FairRoot is used by several different experiments at and outside the GSI including the \\overline{{{P}}}ANDA experiment. FairMQ is an abstract layer for message queue base application, it has up to now two implementations: ZeroMQ and nanomsg. For the \\overline{{{P}}}ANDA experiment, FairMQ is under test in two different ways. On the one hand side for online processing test beam data of prototypes of sub-detectors of \\overline{{{P}}}ANDA and, in a more generalized way, on time-based simulated data of the complete detector system. The first test on test beam data is presented in this paper.

Development and face validity of a cerebral visual impairment motor questionnaire for children with cerebral palsy.

PubMed

Salavati, M; Waninge, A; Rameckers, E A A; van der Steen, J; Krijnen, W P; van der Schans, C P; Steenbergen, B

2017-01-01

The objectives of this study were (i) to develop two cerebral visual impairment motor questionnaires (CVI-MQ's) for children with cerebral palsy (CP): one for children with Gross Motor Function Classification System (GMFCS) levels I, II and III and one for children with GMFCS levels IV and V; (ii) to describe their face validity and usability; and (iii) to determine their sensitivity and specificity. The initial versions of the two CVI-MQ's were developed based on literature. Subsequently, the Delphi method was used in two groups of experts, one familiar with CVI and one not familiar with CVI, in order to gain consensus about face validity and usability. The sensitivity and specificity of the CVI-MQ's were subsequently assessed in 82 children with CP with (n = 39) and without CVI (n = 43). With the receiver operating curve the cut-off scores were determined to detect possible presence or absence of CVI in children with CP. Both questionnaires showed very good face validity (percentage agreement above 96%) and good usability (percentage agreement 95%) for practical use. The CVI-MQ version for GMFCS levels I, II and III had a sensitivity of 1.00 and specificity of 0.96, with a cut-off score of 12 points or higher, and the version for GMFCS levels IV and V had a sensitivity of 0.97 and a specificity of 0.98, with a cut-off score of eight points or higher. The CVI-MQ is able to identify at-risk children with CP for the probability of having CVI. © 2016 John Wiley & Sons Ltd.

Efficacy and Effectiveness of Mefloquine and Artesunate Combination Therapy for Uncomplicated Plasmodium falciparum Malaria in the Peruvian Amazon

PubMed Central

de Oliveira, Alexandre Macedo; Chavez, Jorge; de Leon, Gabriel Ponce; Durand, Salomon; Arrospide, Nancy; Roberts, Jacquelin; Cabezas, Cesar; Marquiño, Wilmer

2011-01-01

We evaluated the efficacy and effectiveness of mefloquine (MQ) plus artesunate (AS) to treat patients with uncomplicated malaria in the Peruvian Amazon Basin in April 2005–March 2006. Patients ≥ 1 year of age with fever (axillary temperature ≥ 37.5°C) or history of fever and Plasmodium falciparum monoinfection were included. Patients received antimalarial treatment with MQ (12.5 mg/kg/day for two days) and AS (4.0 mg/kg/day for three days) either by directly observed therapy or without directly observed therapy. After a 28-day follow-up, treatment efficacy and effectiveness were assessed on the basis of clinical and parasitologic outcomes. Ninety-six patients were enrolled in each study group; nine patients were lost to follow-up. All patients, except for one in the observed group, demonstrated adequate clinical and parasitologic response; none had detectable parasitemia on day 3. The efficacy of MQ + AS efficacy was 98.9% (95% confidence interval = 94.1–100.0%) and the effectiveness was 100.0% (95% confidence interval = 95.9–100.0%). Our study shows that MQ + AS is highly efficacious in the Peruvian Amazon. PMID:21896825

A Preliminary Investigation into Cognitive Aptitudes Predictive of Overall MQ-1 Predator Pilot Qualification Training Performance

DTIC Science & Technology

2015-11-06

Predator pilot vacancies. The purpose of this study was to evaluate computer-based intelligence and neuropsychological testing on training...high-risk, high-demand occupation. 15. SUBJECT TERMS Remotely piloted aircraft, RPA, neuropsychological screening, intelligence testing , computer...based testing , Predator, MQ-1 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 20 19a. NAME OF

Identifying approaches for assessing methodological and reporting quality of systematic reviews: a descriptive study.

PubMed

Pussegoda, Kusala; Turner, Lucy; Garritty, Chantelle; Mayhew, Alain; Skidmore, Becky; Stevens, Adrienne; Boutron, Isabelle; Sarkis-Onofre, Rafael; Bjerre, Lise M; Hróbjartsson, Asbjørn; Altman, Douglas G; Moher, David

2017-06-19

The methodological quality and completeness of reporting of the systematic reviews (SRs) is fundamental to optimal implementation of evidence-based health care and the reduction of research waste. Methods exist to appraise SRs yet little is known about how they are used in SRs or where there are potential gaps in research best-practice guidance materials. The aims of this study are to identify reports assessing the methodological quality (MQ) and/or reporting quality (RQ) of a cohort of SRs and to assess their number, general characteristics, and approaches to 'quality' assessment over time. The Cochrane Library, MEDLINE®, and EMBASE® were searched from January 1990 to October 16, 2014, for reports assessing MQ and/or RQ of SRs. Title, abstract, and full-text screening of all reports were conducted independently by two reviewers. Reports assessing the MQ and/or RQ of a cohort of ten or more SRs of interventions were included. All results are reported as frequencies and percentages of reports. Of 20,765 unique records retrieved, 1189 of them were reviewed for full-text review, of which 76 reports were included. Eight previously published approaches to assessing MQ or reporting guidelines used as proxy to assess RQ were used in 80% (61/76) of identified reports. These included two reporting guidelines (PRISMA and QUOROM) and five quality assessment tools (AMSTAR, R-AMSTAR, OQAQ, Mulrow, Sacks) and GRADE criteria. The remaining 24% (18/76) of reports developed their own criteria. PRISMA, OQAQ, and AMSTAR were the most commonly used published tools to assess MQ or RQ. In conjunction with other approaches, published tools were used in 29% (22/76) of reports, with 36% (8/22) assessing adherence to both PRISMA and AMSTAR criteria and 26% (6/22) using QUOROM and OQAQ. The methods used to assess quality of SRs are diverse, and none has become universally accepted. The most commonly used quality assessment tools are AMSTAR, OQAQ, and PRISMA. As new tools and guidelines are developed to improve both the MQ and RQ of SRs, authors of methodological studies are encouraged to put thoughtful consideration into the use of appropriate tools to assess quality and reporting.

Economic evaluation of an alternative drug to sulfadoxine-pyrimethamine as intermittent preventive treatment of malaria in pregnancy.

PubMed

Sicuri, Elisa; Fernandes, Silke; Macete, Eusebio; González, Raquel; Mombo-Ngoma, Ghyslain; Massougbodgi, Achille; Abdulla, Salim; Kuwawenaruwa, August; Katana, Abraham; Desai, Meghna; Cot, Michel; Ramharter, Michael; Kremsner, Peter; Slustker, Laurence; Aponte, John; Hanson, Kara; Menéndez, Clara

2015-01-01

Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended in HIV-negative women to avert malaria, while this relies on cotrimoxazole prophylaxis (CTXp) in HIV-positive women. Alternative antimalarials are required in areas where parasite resistance to antifolate drugs is high. The cost-effectiveness of IPTp with alternative drugs is needed to inform policy. The cost-effectiveness of 2-dose IPTp-mefloquine (MQ) was compared with IPTp-SP in HIV-negative women (Benin, Gabon, Mozambique and Tanzania). In HIV-positive women the cost-effectiveness of 3-dose IPTp-MQ added to CTXp was compared with CTXp alone (Kenya, Mozambique and Tanzania). The outcomes used were maternal clinical malaria, anaemia at delivery and non-obstetric hospital admissions. The poor tolerability to MQ was included as the value of women's loss of working days. Incremental cost-effectiveness ratios (ICERs) were calculated and threshold analysis undertaken. For HIV-negative women, the ICER for IPTp-MQ versus IPTp-SP was 136.30 US$ (2012 US$) (95%CI 131.41; 141.18) per disability-adjusted life-year (DALY) averted, or 237.78 US$ (95%CI 230.99; 244.57), depending on whether estimates from Gabon were included or not. For HIV-positive women, the ICER per DALY averted for IPTp-MQ added to CTXp, versus CTXp alone was 6.96 US$ (95%CI 4.22; 9.70). In HIV-negative women, moderate shifts of variables such as malaria incidence, drug cost, and IPTp efficacy increased the ICERs above the cost-effectiveness threshold. In HIV-positive women the intervention remained cost-effective for a substantial (up to 21 times) increase in cost per tablet. Addition of IPTp with an effective antimalarial to CTXp was very cost-effective in HIV-positive women. IPTp with an efficacious antimalarial was more cost-effective than IPTp-SP in HIV-negative women. However, the poor tolerability of MQ does not favour its use as IPTp. Regardless of HIV status, prevention of malaria in pregnancy with a highly efficacious, well tolerated antimalarial would be cost-effective despite its high price. ClinicalTrials.gov NCT 00811421; Pan African Trials Registry PACTR2010020001429343 and PACTR2010020001813440.

Syntheses, crystal structure, and electronic properties of the five ABaMQ{sub 4} compounds RbBaPS{sub 4}, CsBaPS{sub 4}, CsBaVS{sub 4}, RbBaVSe{sub 4}, and CsBaVSe{sub 4}

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

Mesbah, Adel; ICSM, UMR 5257 CEA / CNRS / UM / ENSCM, Site de Marcoule-Bâtiment 426, BP 17171, 30207 Bagnols-sur-Cèze Cedex; Prakash, Jai

Five new compounds belonging to the ABaMQ{sub 4} family were synthesized by solid-state chemistry at 1123 K. The compounds RbBaPS{sub 4}, CsBaPS{sub 4}, CsBaVS{sub 4}, RbBaVSe{sub 4}, and CsBaVSe{sub 4} are isostructural and have the TlEuPS{sub 4} structure type. They crystallize in space group D{sup 16}{sub 2h} – Pnma of the orthorhombic system. Their structure consists isolated MQ{sub 4} tetrahedra separated by A and Ba atoms to form a salt-like structure. Density Functional Theory (DFT) calculations of the electronic structures with the use of the HSE functional suggest that the compounds are semiconductors with calculated band gaps of 3.3 eVmore » (RbBaPS{sub 4}), 3.4 eV (CsBaPS{sub 4}), 2.3 eV (CsBaVS{sub 4}), and 1.6 eV (RbBaVSe{sub 4}). - Graphical abstract: General view of the ABaMQ{sub 4} structure down the a axis. - Highlights: • Five new ABaMQ{sub 4} compounds were synthesized by solid-state chemistry at 1123 K. • RbBaPS{sub 4}, CsBaPS{sub 4}, CsBaVS{sub 4}, RbBaVSe{sub 4}, and CsBaVSe{sub 4} have the TlEuPS{sub 4} structure type. • The compounds are semiconductors with calculated band gaps ranging from 1.6 to 3.4 eV.« less

Tachyonic instability of the scalar mode prior to the QCD critical point based on the functional renormalization-group method in the two-flavor case

NASA Astrophysics Data System (ADS)

Yokota, Takeru; Kunihiro, Teiji; Morita, Kenji

2017-10-01

We establish and elucidate the physical meaning of the appearance of an acausal mode in the sigma mesonic channel, found in the previous work by the present authors, when the system approaches the Z2 critical point. The functional renormalization-group method is applied to the two-flavor quark-meson model with varying current quark mass mq even away from the physical value at which the pion mass is reproduced. We first determine the whole phase structure in the three-dimensional space (T ,μ ,mq) consisting of temperature T , quark chemical potential μ and mq, with the tricritical point, O(4) and Z2 critical lines being located; they altogether make a winglike shape quite reminiscent of those known in the condensed matters with a tricritical point. We then calculate the spectral functions ρσ ,π(ω ,p ) in the scalar and pseudoscalar channel around the critical points. We find that the sigma mesonic mode becomes tachyonic with a superluminal velocity at finite momenta before the system reaches the Z2 point from the lower density, even for mq smaller than the physical value. One of the possible implications of the appearance of such a tachyonic mode at finite momenta is that the assumed equilibrium state with a uniform chiral condensate is unstable toward a state with an inhomogeneous σ condensate. No such anomalous behavior is found in the pseudoscalar channel. We find that the σ -to-2 σ coupling due to finite mq plays an essential role for the drastic modification of the spectral function.

A Persistent Perch: USSOCOMs Use of Organic Space Based ISR

DTIC Science & Technology

2015-05-01

requests, and precious orbits of MQ-1 Predator and MQ-9 Reaper Remotely Piloted Aircraft ( RPA ) are fought over daily by Combatant Commander’s...such a unique mission that simply jockeying for position to share RPA orbits or Satellite time blocks can create gaps in coverage requirements...sic] Eye program will extend the Unmanned Aerial Vehicle ( UAV ) paradigm into space: a dramatically lower unit cost and proliferated numbers of

Longitudinal conductivity in strong magnetic field in perturbative QCD: Complete leading order

NASA Astrophysics Data System (ADS)

Hattori, Koichi; Li, Shiyong; Satow, Daisuke; Yee, Ho-Ung

2017-04-01

We compute the longitudinal electrical conductivity in the presence of a strong background magnetic field in complete leading order of perturbative QCD, based on the assumed hierarchy of scales αse B ≪(mq2,T2)≪e B . We formulate an effective kinetic theory of lowest Landau level quarks with the leading order QCD collision term arising from 1-to-2 processes that become possible due to 1 +1 dimensional Landau level kinematics. In the small mq/T ≪1 regime, the longitudinal conductivity behaves as σz z˜e2(e B )T /(αsmq2log (T /mq)) , where the quark mass dependence can be understood from the chiral anomaly with the axial charge relaxation provided by a finite quark mass mq. We also present parametric estimates for the longitudinal and transverse "color conductivities" in the presence of the strong magnetic field, by computing dominant damping rates for quarks and gluons that are responsible for color charge transportation. We observe that the longitudinal color conductivity is enhanced by the strong magnetic field, which implies that the sphaleron transition rate in perturbative QCD is suppressed by the strong magnetic field due to the enhanced Lenz's law in color field dynamics.

Distance in War: The Experience of MQ-1 and MQ-9 Aircrew

DTIC Science & Technology

2015-01-01

ged, and psychologically impacted by the work they perform. The continuing ethical and moral relativism society uses to place new weapons and methods...outcome of such ignorance results in moral disengagement for the RPA aircrew. Within her article titled, “The End of Military Virtue,” author Laurie...imaginary precipice that we should attempt to turn back from. Based upon centuries of military technological and cultural advancements, we should

Manned-Unmanned Teaming of Aircraft - Literature Search

DTIC Science & Technology

2013-12-01

unmanned aircraft reconnaissance system MQ 8B Fire Scout vertical takeoff and landing unmanned system MQ 5B Hunter medium altitude unmanned aerial...201140, and allows their crew to view sensor data from unmanned aircraft systems (UAS) and send data from the helicopter’s sensors to the ground.35 No...Helicopter, AAI unmanned Aircraft Systems , and Textron Inc. It opened in December 2012 in Huntsville Alabama. It will enable “a software and

Comparative benefit of malaria chemoprophylaxis modelled in United Kingdom travellers.

PubMed

Toovey, Stephen; Nieforth, Keith; Smith, Patrick; Schlagenhauf, Patricia; Adamcova, Miriam; Tatt, Iain; Tomianovic, Danitza; Schnetzler, Gabriel

2014-01-01

Chemoprophylaxis against falciparum malaria is recommended for travellers from non-endemic countries to malarious destinations, but debate continues on benefit, especially with regard to mefloquine. Quantification of benefit for travellers from the United Kingdom (UK) was modelled to assist clinical and public health decision making. The model was constructed utilising: World Tourism Organization data showing total number of arrivals from the UK in countries with moderate or high malaria risk; data from a retrospective UK Clinical Practice Research Datalink (CPRD) drug utilisation study; additional information on chemoprophylaxis, case fatality and tolerability were derived from the travel medicine literature. Chemoprophylaxis with the following agents was considered: atovaquone-proguanil (AP), chloroquine with and without proguanil (C ± P), doxycycline (Dx), mefloquine (Mq). The model was validated for the most recent year with temporally matched datasets for UK travel destinations and imported malaria (2007) against UK Health Protection Agency data on imported malaria. The median (mean) duration of chemoprophylaxis for each agent in weeks (CPRD) was: AP 3.3 (3.5), C ± P 9 (12.1), Dx 8 (10.3), Mq 9 (12.3): the maximum duration of use of all regimens was 52 weeks. The model correctly predicted falciparum malaria deaths and gave a robust estimate of total cases--model: 5 deaths from 1118 cases; UK Health Protection Agency: 5 deaths from 1153 cases. The number needed to take chemoprophylaxis (NNP) to prevent a case of malaria considered against the 'background' reported incidence in non-users of chemoprophylaxis deemed in need of chemoprophylaxis was: C ± P 272, Dx 269, Mq 260, AP 252; the NNP to prevent a UK traveller malaria death was: C ± P 62613, Dx 61923, Mq 59973, AP 58059; increasing the 'background' rate by 50% yielded NNPs of: C ± P 176, Dx 175, Mq 171, AP 168. The impact of substituting atovaquone-proguanil for all mefloquine usage resulted in a 2.3% decrease in estimated infections. The number of travellers experiencing moderate adverse events (AE) or those requiring medical attention or drug withdrawal per case prevented is as follows: C ± P 170, Mq 146, Dx 114, AP 103. The model correctly predicted the number of malaria deaths, providing a robust and reliable estimate of the number of imported malaria cases in the UK, and giving a measure of benefit derived from chemoprophylaxis use against the likely adverse events generated. Overall numbers needed to prevent a malaria infection are comparable among the four options and are sensitive to changes in the background infection rates. Only a limited impact on the number of infections can be expected if Mq is substituted by AP.

On the crystal structure of the vaterite polymorph of CaCO3: a calcium-43 solid-state NMR and computational assessment.

PubMed

Burgess, Kevin M N; Bryce, David L

2015-02-01

The vaterite polymorph of CaCO3 has puzzled crystallographers for decades in part due to difficulties in obtaining single crystals. The multiple proposed structures for the vaterite polymorph of CaCO3 are assessed using a combined (43)Ca solid-state nuclear magnetic resonance (SSNMR) spectroscopic and computational approach. A combination of improved experimental and computational methods, along with a calibrated chemical shift scale and (43)Ca nuclear quadrupole moment, allow for improved insights relative to our earlier work (Bryce et al., J. Am. Chem. Soc. 2008, 130, 9282). Here, we synthesize a (43)Ca isotopically-enriched sample of vaterite and perform high-resolution quadrupolar SSNMR experiments including magic-angle spinning (MAS), double-rotation (DOR), and multiple-quantum (MQ) MAS experiments at magnetic field strengths of 9.4 and 21.1T. We identify one crystallographically unique Ca(2+) site in vaterite with a slight distribution in both chemical shifts and quadrupolar parameters. Both the experimental (43)Ca electric field gradient tensor and the isotropic chemical shift for vaterite are compared to those calculated with the gauge-including projector-augmented-wave (GIPAW) DFT method in an attempt to identify the model that best represents the crystal structure of vaterite. Simulations of (43)Ca DOR and MAS NMR spectra based on the NMR parameters computed for a total of 18 structural models for vaterite allow us to distinguish between these models. Among these 18, the P3221 and C2 structures provide simulated spectra and diffractograms in best agreement with all experimental data. Copyright © 2014 Elsevier Inc. All rights reserved.

Economic Evaluation of an Alternative Drug to Sulfadoxine-Pyrimethamine as Intermittent Preventive Treatment of Malaria in Pregnancy

PubMed Central

Sicuri, Elisa; Fernandes, Silke; Macete, Eusebio; González, Raquel; Mombo-Ngoma, Ghyslain; Massougbodgi, Achille; Abdulla, Salim; Kuwawenaruwa, August; Katana, Abraham; Desai, Meghna; Cot, Michel; Ramharter, Michael; Kremsner, Peter; Slustker, Laurence; Aponte, John; Hanson, Kara; Menéndez, Clara

2015-01-01

Background Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended in HIV-negative women to avert malaria, while this relies on cotrimoxazole prophylaxis (CTXp) in HIV-positive women. Alternative antimalarials are required in areas where parasite resistance to antifolate drugs is high. The cost-effectiveness of IPTp with alternative drugs is needed to inform policy. Methods The cost-effectiveness of 2-dose IPTp-mefloquine (MQ) was compared with IPTp-SP in HIV-negative women (Benin, Gabon, Mozambique and Tanzania). In HIV-positive women the cost-effectiveness of 3-dose IPTp-MQ added to CTXp was compared with CTXp alone (Kenya, Mozambique and Tanzania). The outcomes used were maternal clinical malaria, anaemia at delivery and non-obstetric hospital admissions. The poor tolerability to MQ was included as the value of women’s loss of working days. Incremental cost-effectiveness ratios (ICERs) were calculated and threshold analysis undertaken. Results For HIV-negative women, the ICER for IPTp-MQ versus IPTp-SP was 136.30 US$ (2012 US$) (95%CI 131.41; 141.18) per disability-adjusted life-year (DALY) averted, or 237.78 US$ (95%CI 230.99; 244.57), depending on whether estimates from Gabon were included or not. For HIV-positive women, the ICER per DALY averted for IPTp-MQ added to CTXp, versus CTXp alone was 6.96 US$ (95%CI 4.22; 9.70). In HIV-negative women, moderate shifts of variables such as malaria incidence, drug cost, and IPTp efficacy increased the ICERs above the cost-effectiveness threshold. In HIV-positive women the intervention remained cost-effective for a substantial (up to 21 times) increase in cost per tablet. Conclusions Addition of IPTp with an effective antimalarial to CTXp was very cost-effective in HIV-positive women. IPTp with an efficacious antimalarial was more cost-effective than IPTp-SP in HIV-negative women. However, the poor tolerability of MQ does not favour its use as IPTp. Regardless of HIV status, prevention of malaria in pregnancy with a highly efficacious, well tolerated antimalarial would be cost-effective despite its high price. Trials Registration ClinicalTrials.gov NCT 00811421; Pan African Trials Registry PACTR2010020001429343 and PACTR2010020001813440 PMID:25915616

Covering the Homeland: National Guard Unmanned Aircraft Systems Support for Wildland Firefighting and Natural Disaster Events

DTIC Science & Technology

2008-12-01

OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for...VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington DC 20503. 1 . AGENCY USE ONLY (Leave...National Guard, Unmanned Aircraft System, Wildland Forest Fire, Natural Disaster, MQ- 1 Predator, MQ-9 Reaper, Autonomous Modular Sensor, National

U.S. Special Operations Forces (SOF): Background and Issues for Congress

DTIC Science & Technology

2016-04-08

platforms to include AC-130U, AC-130W, U-28, MQ-1, MQ-9, C-145, C-146 as well as small unmanned aerial systems ( SUAS ), Combat Aviation Advisors, medical...forces can operate in small groups and have the ability to quickly deploy from Navy ships, submarines and aircraft , overseas bases, and forward-based...given greater responsibility for planning and conducting worldwide counterterrorism operations. U.S. Special Operations Command (USSOCOM) has about

Psychological Attributes Critical to the Performance of MQ-1 Predator and MQ-9 Reaper U.S. Air Force Sensor Operators

DTIC Science & Technology

2010-06-25

Deputy, 711 HPW/XP), Roscoe "Yogi" VanCamp,UCa!. USAF, and Mark Marley, M.A., (project manager ) who were critical to the logistical operations of...national security, and international relations. Understanding basic principles of aviation, crew resource management , communicat ion protocols, geo...ain::raft flight controls, instruments, weight, balance), as well as topics in aircrew coordination (e.g., crew resource management and situational

Gallium incorporation into phosphate based glasses: Bulk and thin film properties.

PubMed

Stuart, Bryan W; Grant, Colin A; Stan, George E; Popa, Adrian C; Titman, Jeremy J; Grant, David M

2018-06-01

The osteogenic ions Ca 2+ , P 5+ , Mg 2+ , and antimicrobial ion Ga 3+ were homogenously dispersed into a 1.45 µm thick phosphate glass coating by plasma assisted sputtering onto commercially pure grade titanium. The objective was to deliver therapeutic ions in orthopaedic/dental implants such as cementeless endoprostheses or dental screws. The hardness 4.7 GPa and elastic modulus 69.7 GPa, of the coating were comparable to plasma sprayed hydroxyapatite/dental enamel, whilst superseding femoral cortical bone. To investigate the manufacturing challenge of translation from a target to vapour condensed coating, structural/compositional properties of the target (P51MQ) were compared to the coating (P40PVD) and a melt-quenched equivalent (P40MQ). Following condensation from P51MQ to P40PVD, P 2 O 5 content reduced from 48.9 to 40.5 mol%. This depolymerisation and reduction in the P-O-P bridging oxygen content as determined by 31 P NMR, FTIR and Raman spectroscopy techniques was attributed to a decrease in the P 2 O 5 network former and increases in alkali/alkali-earth cations. P40PVD appeared denser (3.47 vs. 2.70 g cm -3 ) and more polymerised than it's compositionally equivalent P40MQ, showing that structure/ mechanical properties were affected by manufacturing route. Copyright © 2018. Published by Elsevier Ltd.

Role of Pfmdr1 in In Vitro Plasmodium falciparum Susceptibility to Chloroquine, Quinine, Monodesethylamodiaquine, Mefloquine, Lumefantrine, and Dihydroartemisinin

PubMed Central

Wurtz, Nathalie; Fall, Bécaye; Pascual, Aurélie; Fall, Mansour; Baret, Eric; Camara, Cheikhou; Nakoulima, Aminata; Diatta, Bakary; Fall, Khadidiatou Ba; Mbaye, Pape Saliou; Diémé, Yaya; Bercion, Raymond; Wade, Boubacar

2014-01-01

The involvement of Pfmdr1 (Plasmodium falciparum multidrug resistance 1) polymorphisms in antimalarial drug resistance is still debated. Here, we evaluate the association between polymorphisms in Pfmdr1 (N86Y, Y184F, S1034C, N1042D, and D1246Y) and Pfcrt (K76T) and in vitro responses to chloroquine (CQ), mefloquine (MQ), lumefantrine (LMF), quinine (QN), monodesethylamodiaquine (MDAQ), and dihydroartemisinin (DHA) in 174 Plasmodium falciparum isolates from Dakar, Senegal. The Pfmdr1 86Y mutation was identified in 14.9% of the samples, and the 184F mutation was identified in 71.8% of the isolates. No 1034C, 1042N, or 1246Y mutations were detected. The Pfmdr1 86Y mutation was significantly associated with increased susceptibility to MDAQ (P = 0.0023), LMF (P = 0.0001), DHA (P = 0.0387), and MQ (P = 0.00002). The N86Y mutation was not associated with CQ (P = 0.214) or QN (P = 0.287) responses. The Pfmdr1 184F mutation was not associated with various susceptibility responses to the 6 antimalarial drugs (P = 0.168 for CQ, 0.778 for MDAQ, 0.324 for LMF, 0.961 for DHA, 0.084 for QN, and 0.298 for MQ). The Pfmdr1 86Y-Y184 haplotype was significantly associated with increased susceptibility to MDAQ (P = 0.0136), LMF (P = 0.0019), and MQ (P = 0.0001). The additional Pfmdr1 86Y mutation increased significantly the in vitro susceptibility to MDAQ (P < 0.0001), LMF (P < 0.0001), MQ (P < 0.0001), and QN (P = 0.0026) in wild-type Pfcrt K76 parasites. The additional Pfmdr1 86Y mutation significantly increased the in vitro susceptibility to CQ (P = 0.0179) in Pfcrt 76T CQ-resistant parasites. PMID:25199781

The Sensor Irony: How Reliance on Sensor Technology is Limiting Our View of the Battlefield

DTIC Science & Technology

2010-05-10

thermal ) camera, as well as a laser illuminator/range finder.73 Similar to the MQ- 1 , the MQ-9 Reaper is primarily a strike asset for emerging targets...Wescam 14TS. 1 Both systems have an Electro-optical (daylight) TV camera, an Infra-red ( thermal ) camera, as well as a laser illuminator/range finder...Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour

Doomed to Repeat It How the United States Air Force Can Apply History via Counterinsurgency Lessons Learned to Meet Anti-Access/Area Denial Challenges

DTIC Science & Technology

2012-08-01

technology used in the COIN fight are not readily transferable to conflicts against enemies using A2/AD tactics, such as heavy electromagnetic attack...particularly when matched against a technology advanced enemy. Technologies unsuitable for an opposed electromagnetic spectrum are unsurvivable...increased numbers of weapons systems such as the MQ-1, MQ-9, and MC-12. Additionally, open-ended deployments of ISR assets such as the RC-135 RIVET

Important and Critical Psychological Attributes of USAF MQ-1 Predator and MQ-9 Reaper Pilots According to Subject Matter Experts

DTIC Science & Technology

2011-05-01

and skills required for military-specific RPAs such as the Pioneer (e.g., Ref 20,21) and Global Hawk (Nagy JE, Muse K , Eaton G , Phillips A, U.S. Air...Analyses, Predator Pilot Front End Analysis (FEA) Report, SURVIAC-TR-06-203, Feb 2006 ; available through the Defense Technical Information Center to U.S...assessing the critical attributes (e.g., subscales of verbal and performance intelligence quotients ) prior to entering the training pipeline. Aeromedical

Control Infrastructure for a Pulsed Ion Accelerator

NASA Astrophysics Data System (ADS)

Persaud, A.; Regis, M. J.; Stettler, M. W.; Vytla, V. K.

2016-10-01

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

Control Infrastructure for a Pulsed Ion Accelerator

DOE PAGES

Persaud, A.; Regis, M. J.; Stettler, M. W.; ...

2016-07-27

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

Environmental Assessment for the MQ-1 Predator and MQ-9 Reaper Unmanned Aircraft System (UAS) Second Formal Training Unit (FTU-2) Beddown

DTIC Science & Technology

2009-04-01

agreement that the National Aeronautics and Space Administration ( NASA ) has in place. However, with close coordination among all users, C-band...land is owned and administered by the U.S. Bureau of Land Management ( BLM ). White Sands National Monument is located to the southwest. WSMR...for the base. Much of Edwards AFB is surrounded by government lands managed by the BLM , U.S. Forest Service (USFS) and State of California. The

A Comparative Analysis of the Army MQ-8B Fire Scout Vertical Takeoff Unmanned Aerial Vehicle (VTUAV) and Navy MQ-8B Manpower & Training Requirements

DTIC Science & Technology

2009-03-01

manning requirements, Military Occupational Specialty Codes ( MOSC ) are briefly explained. The MOS code ( MOSC ) consists of nine characters and...provides more defined information than a soldier’s MOS. The MOS is used in automated management systems and reports. The MOSC is used in active and...reserve records, reports, authorization documents, and other personnel management systems. The elements of the MOSC are as follows: First three

Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

NASA Astrophysics Data System (ADS)

Bose, Adity; Dey, Debarati; Basu, Samita

2008-04-01

The magnetic field effect (MFE) in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ), with one of the DNA bases, thymine (THN), and its corresponding nucleoside, thymidine (THDN), in acetonitrile (ACN) and sodium dodecylsulfate (SDS) micelles. It has been observed that THN undergoes electron transfer (ET) and hydrogen (H) abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN), and its nucleoside, 2'-deoxyadenosine (ADS), undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.

Development and evaluation of kinetic spectrophotometric assays for horseradish peroxidase by catalytic coupling of paraphenylenediamine and mequinol.

PubMed

Nagaraja, Padmarajaiah; Shivakumar, Anantharaman; Kumar Shrestha, Ashwinee

2009-10-01

This paper presents a novel spectrophotometric method to measure peroxidase activity using paraphenylenediamine dihydrochloride (PPDD) and Mequinol (MQ). The PPDD traps the free radical, and gets oxidized to electrophilic 1,4-diimine; this couples with MQ to an give intense violet-colored chromogenic species with the maximum absorbance at 560 nm. This assay was adopted for the quantification of hydrogen peroxide between 10 x 10(-6) to 80 x 10(-6) M. From the kinetic data, a two-substrate ping-pong mechanism of peroxidase was established. Catalytic efficiency and catalytic power of commercial peroxidase were 0.204 x 10(6) M(-1) min(-1) and 2.86 x 10(-4) min(-1), respectively. The catalytic constant (k(cat)) of the proposed method was 0.2080 x 10(3) min(-1). As a simple, rapid, precise and sensitive technique, PPDD-MQ stands as a potential replacement for the traditional guaiacol method. Applications to the plant extracts increase its relevance in the field of biochemical analysis.

Nuclear Physics and Lattice QCD

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

Beane, Silas

2003-11-01

Impressive progress is currently being made in computing properties and interac- tions of the low-lying hadrons using lattice QCD. However, cost limitations will, for the foreseeable future, necessitate the use of quark masses, Mq, that are signif- icantly larger than those of nature, lattice spacings, a, that are not significantly smaller than the physical scale of interest, and lattice sizes, L, that are not sig- nificantly larger than the physical scale of interest. Extrapolations in the quark masses, lattice spacing and lattice volume are therefore required. The hierarchy of mass scales is: L 1 j Mq j â ºC jmore » a 1 . The appropriate EFT for incorporating the light quark masses, the finite lattice spacing and the lattice size into hadronic observables is C-PT, which provides systematic expansions in the small parame- ters e m L, 1/ Lâ ºC, p/â ºC, Mq/â ºC and aâ ºC . The lattice introduces other unphysical scales as well. Lattice QCD quarks will increasingly be artificially separated« less

Evaluating excited state atomic polarizabilities of chromophores.

PubMed

Heid, Esther; Hunt, Patricia A; Schröder, Christian

2018-03-28

Ground and excited state dipoles and polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine (MQ) and coumarin 153 (C153) in solution have been evaluated using time-dependent density functional theory (TD-DFT). A method for determining the atomic polarizabilities has been developed; the molecular dipole has been decomposed into atomic charge transfer and polarizability terms, and variation in the presence of an electric field has been used to evaluate atomic polarizabilities. On excitation, MQ undergoes very site-specific changes in polarizability while C153 shows significantly less variation. We also conclude that MQ cannot be adequately described by standard atomic polarizabilities based on atomic number and hybridization state. Changes in the molecular polarizability of MQ (on excitation) are not representative of the local site-specific changes in atomic polarizability, thus the overall molecular polarizability ratio does not provide a good approximation for local atom-specific polarizability changes on excitation. Accurate excited state force fields are needed for computer simulation of solvation dynamics. The chromophores considered in this study are often used as molecular probes. The methods and data reported here can be used for the construction of polarizable ground and excited state force fields. Atomic and molecular polarizabilities (ground and excited states) have been evaluated over a range of functionals and basis sets. Different mechanisms for including solvation effects have been examined; using a polarizable continuum model, explicit solvation and via sampling of clusters extracted from a MD simulation. A range of different solvents have also been considered.

Disturbance automated reference toolset (DART): Assessing patterns in ecological recovery from energy development on the Colorado Plateau.

PubMed

Nauman, Travis W; Duniway, Michael C; Villarreal, Miguel L; Poitras, Travis B

2017-04-15

A new disturbance automated reference toolset (DART) was developed to monitor human land surface impacts using soil-type and ecological context. DART identifies reference areas with similar soils, topography, and geology; and compares the disturbance condition to the reference area condition using a quantile-based approach based on a satellite vegetation index. DART was able to represent 26-55% of variation of relative differences in bare ground and 26-41% of variation in total foliar cover when comparing sites with nearby ecological reference areas using the Soil Adjusted Total Vegetation Index (SATVI). Assessment of ecological recovery at oil and gas pads on the Colorado Plateau with DART revealed that more than half of well-pads were below the 25th percentile of reference areas. Machine learning trend analysis of poorly recovering well-pads (quantile<0.23) had out-of-bag error rates between 37 and 40% indicating moderate association with environmental and management variables hypothesized to influence recovery. Well-pads in grasslands (median quantile [MQ]=13%), blackbrush (Coleogyne ramosissima) shrublands (MQ=18%), arid canyon complexes (MQ=18%), warmer areas with more summer-dominated precipitation, and state administered areas (MQ=12%) had low recovery rates. Results showcase the usefulness of DART for assessing discrete surface land disturbances, and highlight the need for more targeted rehabilitation efforts at oil and gas well-pads in the arid southwest US. Published by Elsevier B.V.

Age-related change in handgrip strength in men and women: is muscle quality a contributing factor?

PubMed

Abe, Takashi; Thiebaud, Robert S; Loenneke, Jeremy P

2016-02-01

Age-related changes in muscle quality and muscle mass in the forearm, which relate to decline in handgrip strength (HGS), have not been reported. The purpose of this study was to investigate the relationships between age-related declines in HGS and loss of muscle thickness and/or muscle quality in the forearm of 613 adults (306 men and 307 women) aged 20-89. Anterior forearm muscle thickness (MT-ulna) and HGS were measured using an ultrasound and a hand dynamometer, respectively, in the dominant hand. Muscle quality (fMQ) was defined as a ratio of HGS to MT-ulna. HGS was similar among younger (ages 20-29, 30-39, and 40-49) groups and was progressively lower with increasing age in both sexes. MT-ulna was similar between ages 20-29 and 60-69 in men and between ages 20-29 and 70-79 in women. In men, MT-ulna was lower in ages 70-79 and 80-89 compared with other age groups. In women, MT-ulna was lower in ages 80-89 compared with ages 20-29 and 40-49. In both men and women, fMQ was identical among younger (ages 20-29, 30-39, and 40-49) groups. After that fMQ was progressively lower with age in both men and women. The results indicated that age-related decline in HGS is associated with fMQ, but it appears to be accelerated after the seventh decade due to muscle loss.

Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

NASA Technical Reports Server (NTRS)

Kamine, Tovy Haber; Bendrick, Gregg A.

2008-01-01

Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. cones ) of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of Maximum Eye Movement. However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of Easy Eye Movement, though all were within the cone of Maximum Eye Movement. All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Most instrument displays in conventional aircraft lay within the cone of Easy Eye Movement, though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight. The learning objectives include: 1) Know three physiologic cones of eye/head movement; 2) Understand how instrument displays comply with these design principles in conventional aircraft and an uninhabited aerial vehicle system. Which of the following is NOT a recognized physiologic principle of instrument display design? Cone of Easy Eye Movement 2) Cone of Binocular Eye Movement 3) Cone of Maximum Eye Movement 4) Cone of Head Movement 5) None of the above. Answer: # 2) Cone of Binocular Eye Movement

Untrained consumer assessment of the eating quality of beef: 1. A single composite score can predict beef quality grades.

PubMed

Bonny, S P F; Hocquette, J-F; Pethick, D W; Legrand, I; Wierzbicki, J; Allen, P; Farmer, L J; Polkinghorne, R J; Gardner, G E

2017-08-01

Quantifying consumer responses to beef across a broad range of demographics, nationalities and cooking methods is vitally important for any system evaluating beef eating quality. On the basis of previous work, it was expected that consumer scores would be highly accurate in determining quality grades for beef, thereby providing evidence that such a technique could be used to form the basis of and eating quality grading system for beef. Following the Australian MSA (Meat Standards Australia) testing protocols, over 19 000 consumers from Northern Ireland, Poland, Ireland, France and Australia tasted cooked beef samples, then allocated them to a quality grade; unsatisfactory, good-every-day, better-than-every-day and premium. The consumers also scored beef samples for tenderness, juiciness, flavour-liking and overall-liking. The beef was sourced from all countries involved in the study and cooked by four different cooking methods and to three different degrees of doneness, with each experimental group in the study consisting of a single cooking doneness within a cooking method for each country. For each experimental group, and for the data set as a whole, a linear discriminant function was calculated, using the four sensory scores which were used to predict the quality grade. This process was repeated using two conglomerate scores which are derived from weighting and combining the consumer sensory scores for tenderness, juiciness, flavour-liking and overall-liking, the original meat quality 4 score (oMQ4) (0.4, 0.1, 0.2, 0.3) and current meat quality 4 score (cMQ4) (0.3, 0.1, 0.3, 0.3). From the results of these analyses, the optimal weightings of the sensory scores to generate an 'ideal meat quality 4 score (MQ4)' for each country were calculated, and the MQ4 values that reflected the boundaries between the four quality grades were determined. The oMQ4 weightings were far more accurate in categorising European meat samples than the cMQ4 weightings, highlighting that tenderness is more important than flavour to the consumer when determining quality. The accuracy of the discriminant analysis to predict the consumer scored quality grades was similar across all consumer groups, 68%, and similar to previously reported values. These results demonstrate that this technique, as used in the MSA system, could be used to predict consumer assessment of beef eating quality and therefore to underpin a commercial eating quality guarantee for all European consumers.

Multipolar modes in dielectric disk resonator for wireless power transfer

NASA Astrophysics Data System (ADS)

Song, Mingzhao; Belov, Pavel; Kapitanova, Polina

2017-09-01

We demonstrate a magnetic resonant WPT system based on dielectric disk resonators and investigated the WPT efficiency as a function of separation. It has been demonstrated that the power transfer can be achieved at different multipolar modes. The numerical study shows that the highest WPT efficiency of 99% can be obtained for the MQ mode in an ideal case. However, the efficiency of MQ mode decays much faster than the MD mode which suggests that a trade-off has to be made in the practical WPT system design.

Environmental Assessment for the MQ-1 Predator and MQ-9 Reaper Unmaned Aircraft System (UAS) Second Formal Training Unit (FTU-2) Beddown

DTIC Science & Technology

2009-04-01

Administration ( NASA ) has in place. However, with close coordination among all users, C-band would be available until the primary means to control UAS shifts...Management ( BLM ). White Sands National Monument is located to the southwest. WSMR surrounds the Monument and borders Holloman AFB to the north, west...lands managed by the BLM , U.S. Forest Service (USFS) and State of California. The large population areas of Los Angeles County are located 60 miles

Biochemical measurements of beef are a good predictor of untrained consumer sensory scores across muscles.

PubMed

Bonny, S P F; Gardner, G E; Pethick, D W; Legrand, I; Polkinghorne, R J; Hocquette, J F

2015-01-01

The ability of the biochemical measurements, haem iron, intramuscular fat (IMF%), moisture content, and total, soluble and insoluble collagen contents, to predict untrained consumer sensory scores both across different muscles and within the same muscle from different carcasses were investigated. Sensory scores from 540 untrained French consumers (tenderness, flavour liking, juiciness and overall liking) were obtained for six muscles; outside (m. biceps femoris), topside (m. semimembranosus), striploin (m. longissimus thoracis), rump (m. gluteus medius), oyster blade (m. infraspinatus) and tenderloin (m. psoas major) from each of 18 French and 18 Australian cattle. The four sensory scores were weighted and combined into a single score termed MQ4, which was also analysed. All sensory scores were highly correlated with each other and with MQ4. This in part reflects the fact that MQ4 is derived from the consumer scores for tenderness, juiciness, flavour and overall liking and also reflects an interrelationship between the sensory scores themselves and in turn validates the use of the MQ4 term to reflect the scope of the consumer eating experience. When evaluated across the six different muscles, all biochemical measurements, except soluble collagen, had a significant effect on all of the sensory scores and MQ4. The average magnitude of impact of IMF%, haem iron, moisture content, total and insoluble collagen contents across the four different sensory scores are 34.9, 5.1, 7.2, 36.3 and 41.3, respectively. When evaluated within the same muscle, only IMF% and moisture content had a significant effect on overall liking (5.9 and 6.2, respectively) and flavour liking (6.1 and 6.4, respectively). These results indicate that in a commercial eating quality prediction model including muscle type, only IMF% or moisture content has the capacity to add any precision. However, all tested biochemical measurements, particularly IMF% and insoluble collagen contents, are strong predictors of eating quality when muscle type is not known. This demonstrates their potential usefulness in extrapolating the sensory data derived from these six muscles to other muscles with no sensory data, but with similar biochemical parameters, and therefore reducing the amount of future sensory testing required.

Tensor non-Gaussianity from axion-gauge-fields dynamics: parameter search

NASA Astrophysics Data System (ADS)

Agrawal, Aniket; Fujita, Tomohiro; Komatsu, Eiichiro

2018-06-01

We calculate the bispectrum of scale-invariant tensor modes sourced by spectator SU(2) gauge fields during inflation in a model containing a scalar inflaton, a pseudoscalar axion and SU(2) gauge fields. A large bispectrum is generated in this model at tree-level as the gauge fields contain a tensor degree of freedom, and its production is dominated by self-coupling of the gauge fields. This is a unique feature of non-Abelian gauge theory. The shape of the tensor bispectrum is approximately an equilateral shape for 3lesssim mQlesssim 4, where mQ is an effective dimensionless mass of the SU(2) field normalised by the Hubble expansion rate during inflation. The amplitude of non-Gaussianity of the tensor modes, characterised by the ratio Bh/P2h, is inversely proportional to the energy density fraction of the gauge field. This ratio can be much greater than unity, whereas the ratio from the vacuum fluctuation of the metric is of order unity. The bispectrum is effective at constraining large mQ regions of the parameter space, whereas the power spectrum constrains small mQ regions.

Quercetin derivatives regulate melanosome transportation via EPI64 inhibition and elongate the cell shape of B16 melanoma cells.

PubMed

Yamauchi, Kosei; Mitsunaga, Tohru; Inagaki, Mizuho; Suzuki, Tohru

2015-03-01

4'-O-β-D-glucopyranosyl-quercetin-3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranoside (3C4'GQ), first isolated from Helminthostachys zeylanica root extract, was synthesized as a compound that stimulates intracellular melanogenesis. 3-O-methylquercetin (3MQ) and 3,4',7-O-trimethylquercetin (34'7TMQ) were synthesized as compounds that enhance extracellular melanin formation. The formation of dendrites and the expression of EBP50-PDZ interactor of 64 kDa (EPI64) relating to melanin transportation were investigated using B16 melanoma cells treated with 3C4'GQ, 3MQ, or 34'7TMQ in order to understand the mechanism underlying the observed activities. The influence of 3C4'GQ on the increase of intracellular melanin contents enhanced the expression of EPI64, exhibited no dendrite elongation activity, and inhibited melanin transportation. On the other hand, the increase of extracellular melanin content by 3MQ and 34'7TMQ inhibited the expression of EPI64 and formed elongated cells to stimulate melanin transportation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Identification of a Phytase Gene in Barley (Hordeum vulgare L.)

PubMed Central

Dai, Fei; Qiu, Long; Ye, Lingzhen; Wu, Dezhi; Zhou, Meixue; Zhang, Guoping

2011-01-01

Background Endogenous phytase plays a crucial role in phytate degradation and is thus closely related to nutrient efficiency in barley products. The understanding of genetic information of phytase in barley can provide a useful tool for breeding new barley varieties with high phytase activity. Methodology/Principal Findings Quantitative trait loci (QTL) analysis for phytase activity was conducted using a doubled haploid population. Phytase protein was purified and identified by the LC-ESI MS/MS Shotgun method. Purple acid phosphatase (PAP) gene was sequenced and the position was compared with the QTL controlling phytase activity. A major QTL for phytase activity was mapped to chromosome 5 H in barley. The gene controlling phytase activity in the region was named as mqPhy. The gene HvPAP a was mapped to the same position as mqPhy, supporting the colinearity between HvPAP a and mqPhy. Conclusions/Significance It is the first report on QTLs for phytase activity and the results showed that HvPAP a, which shares a same position with the QTL, is a major phytase gene in barley grains. PMID:21533044

Dynamics of photogenerated carriers near magnetic field driven quantum phase transition in aperiodic multiple quantum wells

NASA Astrophysics Data System (ADS)

Tito, M. A.; Pusep, Yu A.

2018-01-01

Time-resolved magneto-photoluminescence was employed to study the magnetic field induced quantum phase transition separating two phases with different distributions of electrons over quantum wells in an aperiodic multiple quantum well, embedded in a wide AlGaAs parabolic quantum well. Intensities, broadenings and recombination times attributed to the photoluminescence lines emitted from individual quantum wells of the multiple quantum well structure were measured as a function of the magnetic field near the transition. The presented data manifest themselves to the magnetic field driven migration of the free electrons between the quantum wells of the studied multiple quantum well structure. The observed charge transfer was found to influence the screening of the multiple quantum well and disorder potentials. Evidence of the localization of the electrons in the peripheral quantum wells in strong magnetic field is presented.

Evaluating excited state atomic polarizabilities of chromophores† †Electronic supplementary information (ESI) available: Basis set dependence, definition of bond charges, Romberg differentiation, python script to calculate atomic polarizabilities, influence of the cavity radius, atomic polarizabilities of coumarin 153, all tables in atomic units. See DOI: 10.1039/c7cp08549d

PubMed Central

Heid, Esther

2018-01-01

Ground and excited state dipoles and polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine (MQ) and coumarin 153 (C153) in solution have been evaluated using time-dependent density functional theory (TD-DFT). A method for determining the atomic polarizabilities has been developed; the molecular dipole has been decomposed into atomic charge transfer and polarizability terms, and variation in the presence of an electric field has been used to evaluate atomic polarizabilities. On excitation, MQ undergoes very site-specific changes in polarizability while C153 shows significantly less variation. We also conclude that MQ cannot be adequately described by standard atomic polarizabilities based on atomic number and hybridization state. Changes in the molecular polarizability of MQ (on excitation) are not representative of the local site-specific changes in atomic polarizability, thus the overall molecular polarizability ratio does not provide a good approximation for local atom-specific polarizability changes on excitation. Accurate excited state force fields are needed for computer simulation of solvation dynamics. The chromophores considered in this study are often used as molecular probes. The methods and data reported here can be used for the construction of polarizable ground and excited state force fields. Atomic and molecular polarizabilities (ground and excited states) have been evaluated over a range of functionals and basis sets. Different mechanisms for including solvation effects have been examined; using a polarizable continuum model, explicit solvation and via sampling of clusters extracted from a MD simulation. A range of different solvents have also been considered. PMID:29542743

Z -boson decays to a vector quarkonium plus a photon

NASA Astrophysics Data System (ADS)

Bodwin, Geoffrey T.; Chung, Hee Sok; Ee, June-Haak; Lee, Jungil

2018-01-01

We compute the decay rates for the processes Z →V +γ , where Z is the Z -boson, γ is the photon, and V is one of the vector quarkonia J /ψ or ϒ (n S ), with n =1 , 2, or 3. Our computations include corrections through relative orders αs and v2 and resummations of logarithms of mZ2/mQ2, to all orders in αs, at next-to-leading-logarithmic accuracy. (v is the velocity of the heavy quark Q or the heavy antiquark Q ¯ in the quarkonium rest frame, and mZ and mQ are the masses of Z and Q , respectively.) Our calculations are the first to include both the order-αs correction to the light-cone distributions amplitude and the resummation of logarithms of mZ2/mQ2 and are the first calculations for the ϒ (2 S ) and ϒ (3 S ) final states. The resummations of logarithms of mZ2/mQ2 that are associated with the order-αs and order-v2 corrections are carried out by making use of the Abel-Padé method. We confirm the analytic result for the order-v2 correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for Z →J /ψ +γ and Z →ϒ (1 S )+γ differ by 2.0 σ and -4.0 σ , respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.

Therapeutic efficacy test in malaria falciparum in Antioquia, Colombia

PubMed Central

Blair, Silvia; Carmona-Fonseca, Jaime; Piñeros, Juan G; Ríos, Alexandra; Álvarez, Tania; Álvarez, Gonzalo; Tobón, Alberto

2006-01-01

Objective Evaluate the frequency of failure of eight treatments for non-complicated malaria caused by Plasmodium falciparum in patients from Turbo (Urabá region), El Bagre and Zaragoza (Bajo Cauca region), applying the 1998 protocol of the World Health Organization (WHO). Monotherapies using chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ) and sulphadoxine-pyrimethamine (SP), and combinations using chloroquine-sulphadoxine-pyrimethamine (CQ-SP), amodiaquine-sulphadoxine-pyrimethamine (AQ-SP), mefloquine-sulphadoxine-pyrimethamine (MQ-SP) and artesunate-sulphadoxine-pyrimethamine (AS-SP), were examined. Methodology A balanced experimental design with eight groups. Samples were selected based on statistical and epidemiological criteria. Patients were followed for 21 to 28 days, including seven or eight parasitological and clinical evaluations, with an active search for defaulting patients. A non-blinded evaluation of the antimalarial treatment response (early failure, late failure, adequate response) was performed. Results Initially, the loss of patients to follow-up was higher than 40%, but the immediate active search for the cases and the monetary help for transportation expenses of patients, reduced the loss to 6%. The treatment failure was: CQ 82%, AQ 30%, MQ 4%, SP 24%, CQ-SP 17%, AQ-SP 2%, MQ-S-P 0%, AS-SP 3%. Conclusion The characteristics of an optimal epidemiological monitoring system of antimalarial treatment response in Colombia are discussed. It is proposed to focus this on early failure detection, by applying a screening test every two to three years, based on a seven to 14-day follow-up. Clinical and parasitological assessment would be carried out by a general physician and a field microscopist from the local hospital, with active measures to search for defaulter patients at follow-up. PMID:16504002

Evidence for methane and ammonia in the coma of comet P/Halley

NASA Technical Reports Server (NTRS)

Allen, M.; Delitsky, M.; Huntress, W.; Yung, Y.; Ip, W.-H.

1987-01-01

Methane and ammonia abundances in the coma of Halley are derived from Giotto ion mass spectrometer data using an Eulerian model of chemical and physical processes inside the contact surface to simulate Giotto high-intensity spectrometer ion mass spectral data for mass-to-charge ratios (m/q) from 15 to 19. The ratio m/q = 19/18 as a function of distance from the nucleus is not reproduced by a model for a pure water coma. It is necessary to include the presence of NH3, and uniquely NH3, in coma gases in order to explain the data. A ratio of production rates Q(NH3)/Q(H2O) = 0.01 = 0.02 results in model values approximating the Giotto data. Methane is identified as the most probable source of the distinct peak at m/q = 15. The observations are fit best with Q(CH4)/Q(Q2O) = 0.02. The chemical composition of the comet nucleus implied by these production rate ratios is unlike that of the outer planets. On the other hand, there are also significant differences from observations of gas phase interstellar material.

Assessing movement quality in persons with severe mental illness - Reliability and validity of the Body Awareness Scale Movement Quality and Experience.

PubMed

Hedlund, Lena; Gyllensten, Amanda Lundvik; Waldegren, Tomas; Hansson, Lars

2016-05-01

Motor disturbances and disturbed self-recognition are common features that affect mobility in persons with schizophrenia spectrum disorder and bipolar disorder. Physiotherapists in Scandinavia assess and treat movement difficulties in persons with severe mental illness. The Body Awareness Scale Movement Quality and Experience (BAS MQ-E) is a new and shortened version of the commonly used Body Awareness Scale-Health (BAS-H). The purpose of this study was to investigate the inter-rater reliability and the concurrent validity of BAS MQ-E in persons with severe mental illness. The concurrent validity was examined by investigating the relationships between neurological soft signs, alexithymia, fatigue, anxiety, and mastery. Sixty-two persons with severe mental illness participated in the study. The results showed a satisfactory inter-rater reliability (n = 53) and a concurrent validity (n = 62) with neurological soft signs, especially cognitive and perceptual based signs. There was also a concurrent validity linked to physical fatigue and aspects of alexithymia. The scores of BAS MQ-E were in general higher for persons with schizophrenia compared to persons with other diagnoses within the schizophrenia spectrum disorders and bipolar disorder. The clinical implications are presented in the discussion.

Bayesian estimation of true prevalence, sensitivity and specificity of three diagnostic tests for detection of Escherichia coli O157 in cattle feces.

PubMed

Ekong, Pius S; Sanderson, Michael W; Bello, Nora M; Noll, Lance W; Cernicchiaro, Natalia; Renter, David G; Bai, Jianfa; Nagaraja, T G

2017-12-01

Cattle are a reservoir for Escherichia coli O157 and they shed the pathogen in their feces. Fecal contaminants on the hides can be transferred onto carcasses during processing at slaughter plants, thereby serving as a source of foodborne infection in humans. The detection of E. coli O157 in cattle feces is based on culture, immunological, and molecular methods We evaluated the diagnostic sensitivity and specificity of one culture- and two PCR-based tests for the detection of E. coli O157 in cattle feces, and its true prevalence using a Bayesian implementation of latent class models. A total of 576 fecal samples were collected from the floor of pens of finishing feedlot cattle in the central United States during summer 2013. Samples were enriched and subjected to detection of E. coli O157 by culture (immunomagnetic separation, plating on a selective medium, latex agglutination, and indole testing), conventional PCR (cPCR), and multiplex quantitative PCR (mqPCR). The statistical models assumed conditional dependence of the PCR tests and high specificity for culture (mode=99%; 5th percentile=97%). Prior estimates of test parameters were elicited from three experts. Estimated posterior sensitivity (posterior median and 95% highest posterior density intervals) of culture, cPCR, and mqPCR was 49.1% (44.8-53.4%), 59.7% (55.3-63.9%), and 97.3% (95.1-99.0%), respectively. Estimated posterior specificity of culture, cPCR, and mqPCR were 98.7% (96.8-99.8%), 94.1% (87.4-99.1%), and 94.8% (84.1-99.9%), respectively. True prevalence was estimated at 91.3% (88.1-94.2%). There was evidence of a weak conditional dependence between cPCR and mqPCR amongst test positive samples, but no evidence of conditional dependence amongst test negative samples. Sensitivity analyses showed that overall our posterior inference was rather robust to the choice of priors, except for inference on specificity of mqPCR, which was estimated with considerable uncertainty. Our study evaluates performance of three diagnostic tests for detection of E. coli O157 in feces of feedlot cattle which is important for quantifying true fecal prevalence and adjusting for test error in risk modeling. Copyright © 2017 Elsevier B.V. All rights reserved.

Therapeutic efficacy and artemisinin resistance in northern Myanmar: evidence from in vivo and molecular marker studies.

PubMed

Myint, Moe Kyaw; Rasmussen, Charlotte; Thi, Aung; Bustos, Dorina; Ringwald, Pascal; Lin, Khin

2017-04-07

In Myanmar, three types of artemisinin-based combination therapy (ACT) are recommended as first-line treatment of uncomplicated falciparum malaria: artemether-lumefantrine (AL), artesunate-mefloquine (AS + MQ), and dihydroartemisinin-piperaquine (DP). Resistance to both artemisinins and ACT partner drugs has been reported from the Greater Mekong Sub-region, and regular efficacy monitoring of the recommended ACT is conducted in Myanmar. This paper reports on results from studies to monitor the efficacy of the three forms of ACT in sentinel sites in northern Myanmar, and investigations of mutations in the Kelch13 (k13) propeller domain. Seven therapeutic efficacy studies were conducted in 2011-12 and 2014 in three sentinel sites in Myanmar (Tamu, Muse, Tabeikkyin). Three studies were done for the evaluation of AL (204 patients), two studies for AS + MQ (119 patients) and two studies for DP (147 patients). These studies were done according to 2009 standard WHO protocol. Polymorphisms in the k13 propeller domain were examined in dried blood spots collected on day 0. The primary endpoint was adequate clinical and parasitological response (ACPR) on day 28 for AL and on day 42 for DP and AS + MQ, corrected to exclude re-infection using polymerase chain reaction (PCR) genotyping. Safety data were collected through self-reporting. PCR-corrected ACPR was 97.2-100% for AL, 98.6-100% for AS + MQ and 100% for DP across the study sites and years. All studies found a prevalence of k13 mutations (>440) above 23% in the day-0 samples. The F446I mutation was the most common mutation, making up 66.0% of the mutations found. Seven out of nine day-3 positive patients were infected with k13 wild type parasites. The remaining two cases with day-3 parasitaemia had the P574L mutation. The efficacy of AL, AS + MQ and DP remains high in northern Myanmar despite widespread evidence of k13 mutations associated with delayed parasite clearance. This study showed that already in 2012 there was a high frequency of k13 mutations in Myanmar on the border with India. The high efficacy of the recommended ACT gives confidence in the continued recommendation of the use of these treatments in Myanmar. Trial registration numbers ACTRN12611001245987 (registered 06-12-2011) and ACTRN12614000216617 (registered 28-02-2014).

Interface and photoluminescence characteristics of graphene-(GaN/InGaN){sub n} multiple quantum wells hybrid structure

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

Wang, Liancheng, E-mail: wanglc@semi.ac.cn, E-mail: lzq@semi.ac.cn, E-mail: zh.zhang@hebut.edu.cn; Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083; Mind Star

The effects of graphene on the optical properties of active system, e.g., the InGaN/GaN multiple quantum wells, are thoroughly investigated and clarified. Here, we have investigated the mechanisms accounting for the photoluminescence reduction for the graphene covered GaN/InGaN multiple quantum wells hybrid structure. Compared to the bare multiple quantum wells, the photoluminescence intensity of graphene covered multiple quantum wells showed a 39% decrease after excluding the graphene absorption losses. The responsible mechanisms have been identified with the following factors: (1) the graphene two dimensional hole gas intensifies the polarization field in multiple quantum wells, thus steepening the quantum well bandmore » profile and causing hole-electron pairs to further separate; (2) a lower affinity of graphene compared to air leading to a weaker capability to confine the excited hot electrons in multiple quantum wells; and (3) exciton transfer through non-radiative energy transfer process. These factors are theoretically analysed based on advanced physical models of semiconductor devices calculations and experimentally verified by varying structural parameters, such as the indium fraction in multiple quantum wells and the thickness of the last GaN quantum barrier spacer layer.« less

Perfect quantum multiple-unicast network coding protocol

NASA Astrophysics Data System (ADS)

Li, Dan-Dan; Gao, Fei; Qin, Su-Juan; Wen, Qiao-Yan

2018-01-01

In order to realize long-distance and large-scale quantum communication, it is natural to utilize quantum repeater. For a general quantum multiple-unicast network, it is still puzzling how to complete communication tasks perfectly with less resources such as registers. In this paper, we solve this problem. By applying quantum repeaters to multiple-unicast communication problem, we give encoding-decoding schemes for source nodes, internal ones and target ones, respectively. Source-target nodes share EPR pairs by using our encoding-decoding schemes over quantum multiple-unicast network. Furthermore, quantum communication can be accomplished perfectly via teleportation. Compared with existed schemes, our schemes can reduce resource consumption and realize long-distance transmission of quantum information.

Interactions between Carotenoids from Marine Bacteria and Other Micronutrients: Impact on Stability and Antioxidant Activity.

PubMed

Sy, Charlotte; Dangles, Olivier; Borel, Patrick; Caris-Veyrat, Catherine

2015-11-19

Recently isolated spore-forming pigmented marine bacteria Bacillus indicus HU36 are sources of oxygenated carotenoids with original structures (about fifteen distinct yellow and orange pigments with acylated d-glucosyl groups). In this study, we evaluated the stability (sensitivity to iron-induced autoxidation) and antioxidant activity (inhibition of iron-induced lipid peroxidation) of combinations of bacterial HU36 carotenoids with the bacterial vitamin menaquinone MQ-7 and with phenolic antioxidants (vitamin E, chlorogenic acid, rutin). Unexpectedly, MQ-7 strongly improves the ability of HU36 carotenoids to inhibit Fe(II)-induced lipid peroxidation, although MQ-7 was not consumed in the medium. We propose that their interaction modifies the carotenoid antioxidant mechanism(s), possibly by allowing carotenoids to scavenge the initiating radicals. For comparison, β-carotene and lycopene in combination were shown to exhibit a slightly higher stability toward iron-induced autoxidation, as well as an additive antioxidant activity as compared to the carotenoids, individually. HU36 carotenoids and phenolic antioxidants displayed synergistic activities in the inhibition of linoleic acid peroxidation induced by heme iron, but not by free iron. Synergism could arise from antioxidants interacting via electron transfer through the porphyrin nucleus of heme iron. Overall, combining antioxidants acting via complementary mechanisms could be the key for optimizing the activity of this bacterial carotenoid cocktail.

Frequency of functional bowel disorders among healthy volunteers in Mexico City.

PubMed

Schmulson, Max; Ortíz, Orianna; Santiago-Lomeli, Mariana; Gutiérrez-Reyes, Gabriela; Gutiérrez-Ruiz, María Concepción; Robles-Díaz, Guillermo; Morgan, Douglas

2006-01-01

The frequency of functional bowel disorders (FBD) in Mexico using the Rome II criteria is unknown. The Rome II Modular Questionnaire (RII-MQ) was translated into Spanish in coordination with the Rome Committee and their Latin American program. Volunteers were recruited by advertisement in Mexico City, and administered the RII-MQ. The study population consisted of 324 healthy volunteers, with a mean age of 35.7; 66% were female. The most prevalent disorders were heartburn 35%, irritable bowel syndrome (IBS) 35%, functional bloating 21%, proctalgia fugax 21%, and functional constipation 19%. Based on gender, IBS-C was 4 times more frequent in females than males (19 vs. 4.6%) and functional bloating 3 times more frequent (10 vs. 3.7%). Differences according to occupation included a higher prevalence of ulcer-like dyspepsia (p = 0.04), IBS-C (p = 0.018) and proctalgia fugax (p = 0.034) among students. This is the first study to use RII-MQ to determine the prevalence of FBD in urban Mexico. The prevalence of IBS was significant and is related to a number of factors, including the stress of living in an overpopulated city. Selection bias is likely operative. A community-based study is warranted. Copyright 2006 S. Karger AG, Basel

Synthesis, Structure, and Optical Properties of Antiperovskite-Derived Ba2MQ3X (M = As, Sb; Q = S, Se; X = Cl, Br, I) Chalcohalides.

PubMed

Wang, Ruiqi; Zhang, Xian; He, Jianqiao; Bu, Kejun; Zheng, Chong; Lin, Jianhua; Huang, Fuqiang

2018-02-05

Six isostructural antiperovskite-derived chalcohalides, Ba 2 MQ 3 X (M = As, Sb; Q = S, Se; X = Cl, Br, I), crystallizing in the space group Pnma, have been synthesized by solid-state reactions. The crystal structure features a 3D framework with the [XBa 5 ] 9+ disordered square pyramids as building blocks and [MQ 3 ] 3- units filling the interspace. [XBa 5 ] 9+ disordered square pyramids are edge-sharing along [010], derived from the fusing of the two pyramids in octahedral [XBa 6 ] 11+ . Surprisingly, Ba 2 AsS 3 X (X = Cl, Br, I) show almost the same optical band gap of 2.80 eV, and Ba 2 AsSe 3 X (X = Br, I) also have a similar band gap of 2.28 eV. The optical band gap of Ba 2 SbS 3 I is 2.64 eV. First-principles calculations reveal that the optical absorption is attributed to the transitions between Q np at the valence band maximum (VBM) and M np-Q np at the conduction band minimum (CBM). These compounds also possess interesting photoluminescence properties with splitting emission peaks on excitation at 200 nm.

Searching for light dark matter with the SLAC millicharge experiment.

PubMed

Diamond, M; Schuster, P

2013-11-27

New sub-GeV gauge forces ("dark photons") that kinetically mix with the photon provide a promising scenario for MeV-GeV dark matter and are the subject of a program of searches at fixed-target and collider facilities around the world. In such models, dark photons produced in collisions may decay invisibly into dark-matter states, thereby evading current searches. We reexamine results of the SLAC mQ electron beam dump experiment designed to search for millicharged particles and find that it was strongly sensitive to any secondary beam of dark matter produced by electron-nucleus collisions in the target. The constraints are competitive for dark photon masses in the ~1-30 MeV range, covering part of the parameter space that can reconcile the apparent (g-2)(μ) anomaly. Simple adjustments to the original SLAC search for millicharges may extend sensitivity to cover a sizable portion of the remaining (g-2)(μ) anomaly-motivated region. The mQ sensitivity is therefore complementary to ongoing searches for visible decays of dark photons. Compared to existing direct-detection searches, mQ sensitivity to electron-dark-matter scattering cross sections is more than an order of magnitude better for a significant range of masses and couplings in simple models.

The effect of d-lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-methylamphetamine (DOM), pentobarbital and methaqualone on punished responding in control and 5,7-dihydroxytryptamine-treated rats.

PubMed

Commissaris, R L; Lyness, W H; Rech, R H

1981-05-01

The purpose of the present study was to determine the role of central 5-hydroxytryptamine (5-HT) neuronal systems in the effects of d-lysergic acid diethylamide (LSD), 2,5-methoxy-4-methylamphetamine (DOM), pentobarbital (PB) and methaqualone (MQ) on punished responding in rats. Water-deprived rats were trained to drink from a tube that was electrified at intervals (variable interval 21 sec; 0.03 mA current intensity), electrification being signalled by a tone. In daily 10-min control sessions, these animals accepted a relatively constant number of shocks; water consumption was also quite stable. At maximally effective doses PB, and to a lesser extent MQ, produced large (400-600 percent of control) increases in punished responding with little decrease in water intake. Higher doses of these agents produced a significant depression of unpunished responding (water intake). The hallucinogens, on the other hand, produced only moderate (125-175 percent of control) increases in the number of shock received, yet a similar depression of unpunished responding. Selective destruction of 5-HT neurons by intracerebroventricular administration of the neurotoxin 5,7-dihydroxytryptamine per se produced little change in the number of shocks received or water consumed in controls sessions. This destruction of 5-HT neurons failed to alter the effects of PB or MQ on punished or unpunished responding. The increase in punished responding produced by the hallucinogens, however, was blocked by this destruction of 5-HT neurons. Furthermore, the capacity of the hallucinogens to decrease water intake was significantly potentiated by the neurotoxin pretreatment. These data demonstrate that the effects of the hallucinogens LSD and DOM on conditioned suppression are quite different from those of PB and MQ, and that this difference may be due to the extent of 5-HT involvement in the effects of these agents.

Phenotypic and genotypic characterization of Thai isolates of Plasmodium falciparum after an artemisinin resistance containment project.

PubMed

Thita, Thunyapit; Jadsri, Pimrat; Thamkhantho, Jarupatr; Ruang-Areerate, Toon; Suwandittakul, Nantana; Sitthichot, Naruemon; Mahotorn, Kittiya; Tan-Ariya, Peerapan; Mungthin, Mathirut

2018-05-15

In Thailand, artemisinin-based combination therapy (ACT) has been used to treat uncomplicated falciparum malaria since 1995. Unfortunately, artemisinin resistance has been reported from Thailand and other Southeast Asian countries since 2003. Malarone ® , a combination of atovaquone-proguanil (ATQ-PG), has been used to cease artemisinin pressure in some areas along Thai-Cambodia border, as part of an artemisinin resistance containment project since 2009. This study aimed to determine genotypes and phenotypes of Plasmodium falciparum isolates collected from the Thai-Cambodia border after the artemisinin resistance containment project compared with those collected before. One hundred and nine of P. falciparum isolates collected from Thai-Cambodia border from Chanthaburi and Trat provinces during 1988-2016 were used in this study. Of these, 58 isolates were collected after the containment. These parasite isolates were characterized for in vitro antimalarial sensitivities including chloroquine (CQ), quinine (QN), mefloquine (MQ), piperaquine (PPQ), artesunate (AS), dihydroartemisinin (DHA), ATQ and PG and genetic markers for drug resistance including the Kelch13 (k13), Plasmodium falciparum chloroquine resistance transporter (pfcrt), P. falciparum multidrug resistance 1 (pfmdr1) and cytochrome b (cytb) genes. Mean CQ, QN, MQ, PPQ and AS IC 50 s of the parasite isolates collected from 2009 to 2016 exhibited significantly higher than those of parasites collected before 2009. Approximately 57% exhibited in vitro MQ resistance. Approximately 94% of the isolates collected from 2009 to 2016 contained the pfmdr1 184F allele. Mutations of the k13 gene were detected in approximately 90% of the parasites collected from 2009 to 2016 which were significantly higher than the parasite isolates collected before. No ATQ-resistant genotype and phenotype of P. falciparum were found among the isolates collected after the containment project. Although the containment project had been implemented in this area, the expansion of artemisinin-resistant parasites did not decline. In addition, reduced sensitivity of the partner drugs of ACT including MQ and PPQ were identified.

Efficacy and safety of a combination of azithromycin and chloroquine for the treatment of uncomplicated Plasmodium falciparum malaria in two multi-country randomised clinical trials in African adults.

PubMed

Sagara, Issaka; Oduro, Abraham R; Mulenga, Modest; Dieng, Yemou; Ogutu, Bernhards; Tiono, Alfred B; Mugyenyi, Peter; Sie, Ali; Wasunna, Monique; Kain, Kevin C; Djimdé, Abdoulaye A; Sarkar, Shirsendu; Chandra, Richa; Robbins, Jeffery; Dunne, Michael W

2014-11-25

Given increasing rates of resistance to existing therapy, new options for treatment and prophylaxis of malaria are needed. Two randomised, comparative, non-inferiority studies were conducted in Africa, one double-blinded and one open-label. Adults with fever, a positive peripheral blood smear, and a positive rapid diagnostic test for Plasmodium falciparum were randomised in both studies to either azithromycin (AZ) 1,000 mg plus chloroquine (CQ) 600-mg base (AZCQ 1,000 mg) once daily for three days or mefloquine hydrochloride (MQ) 1,250 mg (split dose). In the first study, an additional regimen of AZ 500 mg plus CQ 600-mg base (AZCQ 500 mg) once daily for three days was included. All study participants were hospitalised until three consecutive daily blood smears were negative for asexual P. falciparum parasitaemia. Study participants were evaluated weekly for 42 days, with Day 28 polymerase chain reaction (PCR)-corrected parasitological clearance rate as primary endpoint. A total of 467 subjects were randomised in the two studies. At 28 days' follow-up, PCR-corrected parasitological clearance rates in the per protocol population in the first study were 101/103 (98%) with AZCQ 1,000 mg compared with 102/103 (99%) with MQ (95% confidence interval [CI]: -5.2, 3.3). The AZCQ 500-mg regimen was stopped during an interim study review (six [86%] clearance of seven evaluable; two lost to follow-up). In the second study, clearance rates were similar: AZCQ 1,000 mg 107/107 (100%) vs MQ 111/112 (99%; 95% CI: -1.8, 3.6). Among the participating countries, in vitro CQ resistance based on pfcrt mutation frequency in the baseline isolates across both studies ranged from 20.8% (Zambia) to 96.1% (Uganda). Serious adverse events (AEs; all causality) were observed more frequently with MQ compared with AZCQ (four vs one, respectively), though discontinuations for AEs were similar (four vs three, respectively). Common AEs in the AZ-containing arms included pruritus, vomiting, dizziness, and headache. Among adults with symptomatic uncomplicated falciparum malaria in Africa, the combination of AZ 1,000 mg and CQ 600-mg base once daily for three days resulted in Day 28 PCR-corrected parasitological clearance rates of ≥98% and was non-inferior to treatment with MQ. AZCQ was well tolerated. ClinicalTrials.gov identifiers NCT00082576 and NCT00367653.

Quantum internet using code division multiple access

PubMed Central

Zhang, Jing; Liu, Yu-xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

2013-01-01

A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels. PMID:23860488

Interactions between Carotenoids from Marine Bacteria and Other Micronutrients: Impact on Stability and Antioxidant Activity

PubMed Central

Sy, Charlotte; Dangles, Olivier; Borel, Patrick; Caris-Veyrat, Catherine

2015-01-01

Recently isolated spore-forming pigmented marine bacteria Bacillus indicus HU36 are sources of oxygenated carotenoids with original structures (about fifteen distinct yellow and orange pigments with acylated d-glucosyl groups). In this study, we evaluated the stability (sensitivity to iron-induced autoxidation) and antioxidant activity (inhibition of iron-induced lipid peroxidation) of combinations of bacterial HU36 carotenoids with the bacterial vitamin menaquinone MQ-7 and with phenolic antioxidants (vitamin E, chlorogenic acid, rutin). Unexpectedly, MQ-7 strongly improves the ability of HU36 carotenoids to inhibit FeII-induced lipid peroxidation, although MQ-7 was not consumed in the medium. We propose that their interaction modifies the carotenoid antioxidant mechanism(s), possibly by allowing carotenoids to scavenge the initiating radicals. For comparison, β-carotene and lycopene in combination were shown to exhibit a slightly higher stability toward iron-induced autoxidation, as well as an additive antioxidant activity as compared to the carotenoids, individually. HU36 carotenoids and phenolic antioxidants displayed synergistic activities in the inhibition of linoleic acid peroxidation induced by heme iron, but not by free iron. Synergism could arise from antioxidants interacting via electron transfer through the porphyrin nucleus of heme iron. Overall, combining antioxidants acting via complementary mechanisms could be the key for optimizing the activity of this bacterial carotenoid cocktail. PMID:26610529

Changes in physical fitness and sports participation among children with different levels of motor competence: a 2-year longitudinal study.

PubMed

Fransen, Job; Deprez, Dieter; Pion, Johan; Tallir, Isabel B; D'Hondt, Eva; Vaeyens, Roel; Lenoir, Matthieu; Philippaerts, Renaat M

2014-02-01

The goal of this study was to investigate differences in physical fitness and sports participation over 2 years in children with relatively high, average, and low motor competence. Physical fitness and gross motor coordination of 501 children between 6-10 years were measured at baseline and baseline+2 years. The sample compromised 2 age cohorts: 6.00-7.99 and 8.00-9.99 years. An age and sex-specific motor quotient at baseline testing was used to subdivide these children into low (MQ < P33), average (P33 ≤ MQ < P66) and high (MQ ≥ P66) motor competence groups. Measures of sports participation were obtained through a physical activity questionnaire in 278 of the same children. Repeated Measures MANCOVA and two separate ANOVAs were used to analyze differences in changes in physical fitness and measures of sports participation respectively. Children with high motor competence scored better on physical fitness tests and participated in sports more often. Since physical fitness levels between groups changed similarly over time, low motor competent children might be at risk for being less physically fit throughout their life. Furthermore, since low motor competent children participate less in sports, they have fewer opportunities of developing motor abilities and physical fitness and this may further prevent them from catching up with their peers with an average or high motor competence.

Validity of an Athletic Skills Track among 6- to 12-year-old children.

PubMed

Hoeboer, Joris; De Vries, Sanne; Krijger-Hombergen, Michiel; Wormhoudt, René; Drent, Annelies; Krabben, Kay; Savelsbergh, Geert

2016-11-01

The purpose of this study was to examine the feasibility and validity of an Athletic Skills Track (AST) to assess fundamental movement skills among 6- to 12-year-old children in a physical education setting. Four hundred sixty-three Dutch children (211 girls, 252 boys) completed three tests: the Körperkoordinationstest für Kinder (KTK) and two Athletic Skills Tracks (AST-1, AST-2). The validity of AST-1 and AST-2 was examined by correlating the time (s) needed to complete the tracks and the KTK Motor Quotient (MQ). Overall, there was a low correlation between AST-1 and the KTK MQ (r = -0.474 (P < 0.01)) and a moderate correlation between AST-2 and the KTK MQ (r = -0.502 (P < 0.01)). When split up by age group the associations were much higher and ranged between r = -0.469 and r = -0.767), with the exception of the low correlation coefficient of the AST-2 in 7-year-olds. The results indicate that fundamental movement skills of 6- to 12-year-old children can be assessed with a quick, convenient and low-cost motor competence test in a physical education setting, i.e., an Athletic Skills Track. Future studies should further assess the reliability, discriminative ability and validity of age-specific versions of the AST.

Orthogonal time-of-flight mass spectrometry of an ion beam with a broad kinetic energy profile.

PubMed

Miller, S W; Prince, B D; Bemish, R J

2017-10-01

A combined experimental and modeling effort is undertaken to assess a detection system composed of an orthogonal extraction time-of-flight (TOF) mass spectrometer coupled to a continuous ion source emitting an ion beam with kinetic energy of several hundred eV. The continuous ion source comprises an electrospray capillary system employing an undiluted ionic liquid emitting directly into vacuum. The resulting ion beam consists of ions with kinetic energy distributions of width greater than a hundred of eV and mass-to-charge (m/q) ratios ranging from 111 to 500 000 amu/q. In particular, the investigation aims to demonstrate the kinetic energy resolution along the ion beam axis (axial) of orthogonally extracted ions in measurements of the axial kinetic energy-specific mass spectrum, mass flow rate, and total ion current. The described instrument is capable of simultaneous measurement of a broad m/q range in a single acquisition cycle with approximately 25 eV/q axial kinetic energy resolution. Mass resolutions of ∼340 (M/ΔM, FWHM) were obtained for ions at m/q = 1974. Comparison of the orthogonally extracted TOF mass spectrum to mass flow and ion current measurements obtained with a quartz-crystal microbalance and Faraday cup, respectively, shows reasonable numeric agreement and qualitative agreement in the trend as a function of energy defect.

Secure Multiparty Quantum Computation for Summation and Multiplication.

PubMed

Shi, Run-hua; Mu, Yi; Zhong, Hong; Cui, Jie; Zhang, Shun

2016-01-21

As a fundamental primitive, Secure Multiparty Summation and Multiplication can be used to build complex secure protocols for other multiparty computations, specially, numerical computations. However, there is still lack of systematical and efficient quantum methods to compute Secure Multiparty Summation and Multiplication. In this paper, we present a novel and efficient quantum approach to securely compute the summation and multiplication of multiparty private inputs, respectively. Compared to classical solutions, our proposed approach can ensure the unconditional security and the perfect privacy protection based on the physical principle of quantum mechanics.

Secure Multiparty Quantum Computation for Summation and Multiplication

PubMed Central

Shi, Run-hua; Mu, Yi; Zhong, Hong; Cui, Jie; Zhang, Shun

2016-01-01

As a fundamental primitive, Secure Multiparty Summation and Multiplication can be used to build complex secure protocols for other multiparty computations, specially, numerical computations. However, there is still lack of systematical and efficient quantum methods to compute Secure Multiparty Summation and Multiplication. In this paper, we present a novel and efficient quantum approach to securely compute the summation and multiplication of multiparty private inputs, respectively. Compared to classical solutions, our proposed approach can ensure the unconditional security and the perfect privacy protection based on the physical principle of quantum mechanics. PMID:26792197

Experimental realization of entanglement in multiple degrees of freedom between two quantum memories.

PubMed

Zhang, Wei; Ding, Dong-Sheng; Dong, Ming-Xin; Shi, Shuai; Wang, Kai; Liu, Shi-Long; Li, Yan; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2016-11-14

Entanglement in multiple degrees of freedom has many benefits over entanglement in a single one. The former enables quantum communication with higher channel capacity and more efficient quantum information processing and is compatible with diverse quantum networks. Establishing multi-degree-of-freedom entangled memories is not only vital for high-capacity quantum communication and computing, but also promising for enhanced violations of nonlocality in quantum systems. However, there have been yet no reports of the experimental realization of multi-degree-of-freedom entangled memories. Here we experimentally established hyper- and hybrid entanglement in multiple degrees of freedom, including path (K-vector) and orbital angular momentum, between two separated atomic ensembles by using quantum storage. The results are promising for achieving quantum communication and computing with many degrees of freedom.

Superlattice photoelectrodes for photoelectrochemical cells

DOEpatents

Nozik, Arthur J.

1987-01-01

A superlattice or multiple-quantum-well semiconductor is used as a photoelectrode in a photoelectrochemical process for converting solar energy into useful fuels or chemicals. The quantum minibands of the superlattice or multiple-quantum-well semiconductor effectively capture hot-charge carriers at or near their discrete quantum energies and deliver them to drive a chemical reaction in an electrolyte. The hot-charge carries can be injected into the electrolyte at or near the various discrete multiple energy levels quantum minibands, or they can be equilibrated among themselves to a hot-carrier pool and then injected into the electrolyte at one average energy that is higher than the lowest quantum band gap in the semiconductor.

High charge-carrier mobility enables exploitation of carrier multiplication in quantum-dot films

PubMed Central

Sandeep, C. S. Suchand; Cate, Sybren ten; Schins, Juleon M.; Savenije, Tom J.; Liu, Yao; Law, Matt; Kinge, Sachin; Houtepen, Arjan J.; Siebbeles, Laurens D. A.

2013-01-01

Carrier multiplication, the generation of multiple electron–hole pairs by a single photon, is of great interest for solar cells as it may enhance their photocurrent. This process has been shown to occur efficiently in colloidal quantum dots, however, harvesting of the generated multiple charges has proved difficult. Here we show that by tuning the charge-carrier mobility in quantum-dot films, carrier multiplication can be optimized and may show an efficiency as high as in colloidal dispersion. Our results are explained quantitatively by the competition between dissociation of multiple electron–hole pairs and Auger recombination. Above a mobility of ~1 cm2 V−1 s−1, all charges escape Auger recombination and are quantitatively converted to free charges, offering the prospect of cheap quantum-dot solar cells with efficiencies in excess of the Shockley–Queisser limit. In addition, we show that the threshold energy for carrier multiplication is reduced to twice the band gap of the quantum dots. PMID:23974282

Phosphor-Free Apple-White LEDs with Embedded Indium-Rich Nanostructures Grown on Strain Relaxed Nano-epitaxy GaN.

PubMed

Soh, C B; Liu, W; Yong, A M; Chua, S J; Chow, S Y; Tripathy, S; Tan, R J N

2010-08-01

Phosphor-free apple-white light emitting diodes have been fabricated using a dual stacked InGaN/GaN multiple quantum wells comprising of a lower set of long wavelength emitting indium-rich nanostructures incorporated in multiple quantum wells with an upper set of cyan-green emitting multiple quantum wells. The light-emitting diodes were grown on nano-epitaxially lateral overgrown GaN template formed by regrowth of GaN over SiO(2) film patterned with an anodic aluminum oxide mask with holes of 125 nm diameter and a period of 250 nm. The growth of InGaN/GaN multiple quantum wells on these stress relaxed low defect density templates improves the internal quantum efficiency by 15% for the cyan-green multiple quantum wells. Higher emission intensity with redshift in the PL peak emission wavelength is obtained for the indium-rich nanostructures incorporated in multiple quantum wells. The quantum wells grown on the nano-epitaxially lateral overgrown GaN has a weaker piezoelectric field and hence shows a minimal peak shift with application of higher injection current. An enhancement of external quantum efficiency is achieved for the apple-white light emitting diodes grown on the nano-epitaxially lateral overgrown GaN template based on the light -output power measurement. The improvement in light extraction efficiency, η(extraction,) was found to be 34% for the cyan-green emission peak and 15% from the broad long wavelength emission with optimized lattice period.

Phosphor-Free Apple-White LEDs with Embedded Indium-Rich Nanostructures Grown on Strain Relaxed Nano-epitaxy GaN

NASA Astrophysics Data System (ADS)

Soh, C. B.; Liu, W.; Yong, A. M.; Chua, S. J.; Chow, S. Y.; Tripathy, S.; Tan, R. J. N.

2010-11-01

Phosphor-free apple-white light emitting diodes have been fabricated using a dual stacked InGaN/GaN multiple quantum wells comprising of a lower set of long wavelength emitting indium-rich nanostructures incorporated in multiple quantum wells with an upper set of cyan-green emitting multiple quantum wells. The light-emitting diodes were grown on nano-epitaxially lateral overgrown GaN template formed by regrowth of GaN over SiO2 film patterned with an anodic aluminum oxide mask with holes of 125 nm diameter and a period of 250 nm. The growth of InGaN/GaN multiple quantum wells on these stress relaxed low defect density templates improves the internal quantum efficiency by 15% for the cyan-green multiple quantum wells. Higher emission intensity with redshift in the PL peak emission wavelength is obtained for the indium-rich nanostructures incorporated in multiple quantum wells. The quantum wells grown on the nano-epitaxially lateral overgrown GaN has a weaker piezoelectric field and hence shows a minimal peak shift with application of higher injection current. An enhancement of external quantum efficiency is achieved for the apple-white light emitting diodes grown on the nano-epitaxially lateral overgrown GaN template based on the light -output power measurement. The improvement in light extraction efficiency, ηextraction, was found to be 34% for the cyan-green emission peak and 15% from the broad long wavelength emission with optimized lattice period.

Probing a new strongly interacting sector via composite diboson resonances

NASA Astrophysics Data System (ADS)

Ko, P.; Yu, Chaehyun; Yuan, Tzu-Chiang

2017-06-01

Diphoton resonance was a crucial discovery mode for the 125 GeV Standard Model Higgs boson at the Large Hadron Collider (LHC). This mode or the more general diboson modes may also play an important role in probing for new physics beyond the Standard Model. In this paper, we consider the possibility that a diphoton resonance is due to a composite scalar or pseudoscalar boson, whose constituents are either new hyperquarks Q or scalar hyperquarks Q ˜ confined by a new hypercolor force at a confinement scale Λh. Assuming the mass mQ (or mQ ˜) ≫Λh, a diphoton resonance could be interpreted as either a Q Q ¯ (1S0) state ηQ with JP C=0-+ or a Q ˜ Q˜ †(1S0) state ηQ ˜ with JP C=0++. For the Q Q ¯ scenario, there will be a spin-triplet partner ψQ which is slightly heavier than ηQ due to the hyperfine interactions mediated by hypercolor gluon exchange; while for the Q ˜Q˜† scenario, the spin-triplet partner χQ ˜ arises from higher radial excitation with nonzero orbital angular momentum. We consider productions and decays of ηQ, ηQ ˜, ψQ, and χQ ˜ at the LHC using the nonrelativistic QCD factorization approach. We discuss how to test these scenarios by using the Drell-Yan process and the forward dijet azimuthal angular distributions to determine the JP C quantum number of the diphoton resonance. Constraints on the parameter space can be obtained by interpreting some of the small diphoton "excesses" reported by the LHC as the composite scalar or pseudoscalar of the model. Another important test of the model is the presence of a nearby hypercolor-singlet but color-octet state like the 1S0 state ηQ8 or ηQ˜8, which can also be constrained by dijet or monojet plus monophoton data. Both possibilities of a large or small width of the resonance can be accommodated, depending on whether the hyper-glueball states are kinematically allowed in the final state or not.

Efficient quantum transmission in multiple-source networks.

PubMed

Luo, Ming-Xing; Xu, Gang; Chen, Xiu-Bo; Yang, Yi-Xian; Wang, Xiaojun

2014-04-02

A difficult problem in quantum network communications is how to efficiently transmit quantum information over large-scale networks with common channels. We propose a solution by developing a quantum encoding approach. Different quantum states are encoded into a coherent superposition state using quantum linear optics. The transmission congestion in the common channel may be avoided by transmitting the superposition state. For further decoding and continued transmission, special phase transformations are applied to incoming quantum states using phase shifters such that decoders can distinguish outgoing quantum states. These phase shifters may be precisely controlled using classical chaos synchronization via additional classical channels. Based on this design and the reduction of multiple-source network under the assumption of restricted maximum-flow, the optimal scheme is proposed for specially quantized multiple-source network. In comparison with previous schemes, our scheme can greatly increase the transmission efficiency.

Experimental realization of entanglement in multiple degrees of freedom between two quantum memories

PubMed Central

Zhang, Wei; Ding, Dong-Sheng; Dong, Ming-Xin; Shi, Shuai; Wang, Kai; Liu, Shi-Long; Li, Yan; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2016-01-01

Entanglement in multiple degrees of freedom has many benefits over entanglement in a single one. The former enables quantum communication with higher channel capacity and more efficient quantum information processing and is compatible with diverse quantum networks. Establishing multi-degree-of-freedom entangled memories is not only vital for high-capacity quantum communication and computing, but also promising for enhanced violations of nonlocality in quantum systems. However, there have been yet no reports of the experimental realization of multi-degree-of-freedom entangled memories. Here we experimentally established hyper- and hybrid entanglement in multiple degrees of freedom, including path (K-vector) and orbital angular momentum, between two separated atomic ensembles by using quantum storage. The results are promising for achieving quantum communication and computing with many degrees of freedom. PMID:27841274

Southern African Phanerozoic Carbonatites: Perspectives on Their Sources and Petrogeneses

NASA Astrophysics Data System (ADS)

Janney, P. E.; Ogungbuyi, P. I.; Marageni, M.; Harris, C.; Reid, D. L.

2017-12-01

Found worldwide, carbonatites are particularly numerous in southern Africa and reflect one expression of abundant intraplate alkaline magmatism of Proterozoic to Paleogene age in the region. Phanerozoic southern African carbonatites tend to be concentrated near the margins of the continent (especially the western margin), and near the East African Rift, and often occur in discrete magmatic lineations also containing kimberlites, melilitites, nephelinites and differentiated silica-undersaturated rocks such as phonolites and syenites. We present a synthesis of geochemical and radiogenic and stable isotope results for southern African carbonatites, including new trace element and isotope data from four Phanerozoic carbonatite complexes in South Africa and Namibia: Marinkas Quellen (MQ; southernmost Namibia, ≈525 Ma), Saltpeterkop (SPK; near Sutherland, South Africa, 74 Ma), Zandkopsdrift (ZKD; near Garies, South Africa, 55 Ma, a major REE deposit in development), and Dicker Willem (DW; near Aus, southern Namibia, 49 Ma). All are located in the Early-mid Proterozoic Namaqua-Natal mobile belt. These carbonatite complexes are each associated with linear, NE-SW oriented magmatic provinces, i.e., the Kuboos-Bremen Line of felsic alkaline intrusions and ultramafic lamprophyres (MQ); the Western Cape olivine melilitite province (SPK); the Namaqualand-Bushmanland-Warmbad province of olivine melilitites and kimberlites (ZKD) and the Schwarzeberg-Klinghardt-Gibeon swarm of nephelinites, phonolites and kimberlites (DW), the latter three provinces are of Paleogene to Late Cretaceous age and are clearly age progressive. Each of the four carbonatite complexes contain silica-undersaturated igneous rocks such as potassic trachyte (MQ, SPK & DW), alkaline lamprophyre (ZKD), ijolite (MQ & DW) and olivine melilitite (ZKD and SPK). Most also contain hybrid silicate-carbonate igneous rocks with <35 wt.% SiO2 and ≥20 wt.% CO2 such as nepheline sövite (DW), aillikite (ZKD) and other carbonated ultramafic lamprophyre types (SPK) that could represent magmas parental to the carbonatites. Like the magmatic provinces that host them, the carbonatites span a range of isotopic compositions from strong HIMU to EM1. We will present a model of carbonatite origin and source evolution related to lithospheric setting.

A lightweight messaging-based distributed processing and workflow execution framework for real-time and big data analysis

NASA Astrophysics Data System (ADS)

Laban, Shaban; El-Desouky, Aly

2014-05-01

To achieve a rapid, simple and reliable parallel processing of different types of tasks and big data processing on any compute cluster, a lightweight messaging-based distributed applications processing and workflow execution framework model is proposed. The framework is based on Apache ActiveMQ and Simple (or Streaming) Text Oriented Message Protocol (STOMP). ActiveMQ , a popular and powerful open source persistence messaging and integration patterns server with scheduler capabilities, acts as a message broker in the framework. STOMP provides an interoperable wire format that allows framework programs to talk and interact between each other and ActiveMQ easily. In order to efficiently use the message broker a unified message and topic naming pattern is utilized to achieve the required operation. Only three Python programs and simple library, used to unify and simplify the implementation of activeMQ and STOMP protocol, are needed to use the framework. A watchdog program is used to monitor, remove, add, start and stop any machine and/or its different tasks when necessary. For every machine a dedicated one and only one zoo keeper program is used to start different functions or tasks, stompShell program, needed for executing the user required workflow. The stompShell instances are used to execute any workflow jobs based on received message. A well-defined, simple and flexible message structure, based on JavaScript Object Notation (JSON), is used to build any complex workflow systems. Also, JSON format is used in configuration, communication between machines and programs. The framework is platform independent. Although, the framework is built using Python the actual workflow programs or jobs can be implemented by any programming language. The generic framework can be used in small national data centres for processing seismological and radionuclide data received from the International Data Centre (IDC) of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Also, it is possible to extend the use of the framework in monitoring the IDC pipeline. The detailed design, implementation,conclusion and future work of the proposed framework will be presented.

Experimental characterization of quantum correlated triple beams generated by cascaded four-wave mixing processes

NASA Astrophysics Data System (ADS)

Qin, Zhongzhong; Cao, Leiming; Jing, Jietai

2015-05-01

Quantum correlations and entanglement shared among multiple modes are fundamental ingredients of most continuous-variable quantum technologies. Recently, a method used to generate multiple quantum correlated beams using cascaded four-wave mixing (FWM) processes was theoretically proposed and experimentally realized by our group [Z. Qin et al., Phys. Rev. Lett. 113, 023602 (2014)]. Our study of triple-beam quantum correlation paves the way to showing the tripartite entanglement in our system. Our system also promises to find applications in quantum information and precision measurement such as the controlled quantum communications, the generation of multiple quantum correlated images, and the realization of a multiport nonlinear interferometer. For its applications, the degree of quantum correlation is a crucial figure of merit. In this letter, we experimentally study how various parameters, such as the cell temperatures, one-photon, and two-photon detunings, influence the degree of quantum correlation between the triple beams generated from the cascaded two-FWM configuration.

Experimental characterization of quantum correlated triple beams generated by cascaded four-wave mixing processes

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

Qin, Zhongzhong; Cao, Leiming; Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn

2015-05-25

Quantum correlations and entanglement shared among multiple modes are fundamental ingredients of most continuous-variable quantum technologies. Recently, a method used to generate multiple quantum correlated beams using cascaded four-wave mixing (FWM) processes was theoretically proposed and experimentally realized by our group [Z. Qin et al., Phys. Rev. Lett. 113, 023602 (2014)]. Our study of triple-beam quantum correlation paves the way to showing the tripartite entanglement in our system. Our system also promises to find applications in quantum information and precision measurement such as the controlled quantum communications, the generation of multiple quantum correlated images, and the realization of a multiportmore » nonlinear interferometer. For its applications, the degree of quantum correlation is a crucial figure of merit. In this letter, we experimentally study how various parameters, such as the cell temperatures, one-photon, and two-photon detunings, influence the degree of quantum correlation between the triple beams generated from the cascaded two-FWM configuration.« less

Quantum filtering for multiple diffusive and Poissonian measurements

NASA Astrophysics Data System (ADS)

Emzir, Muhammad F.; Woolley, Matthew J.; Petersen, Ian R.

2015-09-01

We provide a rigorous derivation of a quantum filter for the case of multiple measurements being made on a quantum system. We consider a class of measurement processes which are functions of bosonic field operators, including combinations of diffusive and Poissonian processes. This covers the standard cases from quantum optics, where homodyne detection may be described as a diffusive process and photon counting may be described as a Poissonian process. We obtain a necessary and sufficient condition for any pair of such measurements taken at different output channels to satisfy a commutation relationship. Then, we derive a general, multiple-measurement quantum filter as an extension of a single-measurement quantum filter. As an application we explicitly obtain the quantum filter corresponding to homodyne detection and photon counting at the output ports of a beam splitter.

Time-domain multiple-quantum NMR

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

Weitekamp, Daniel P.

1982-11-01

The development of time-domain multiple-quantum nuclear magnetic resonance is reviewed through mid 1982 and some prospects for future development are indicated. Particular attention is given to the problem of obtaining resolved, interpretable, many-quantum spectra for anisotropic magnetically isolated systems of coupled spins. New results are presented on a number of topics including the optimization of multiple-quantum-line intensities, analysis of noise in two-dimensional spectroscopy, and the use of order-selective excitation for cross polarization between nuclear-spin species.

Efficient Quantum Transmission in Multiple-Source Networks

PubMed Central

Luo, Ming-Xing; Xu, Gang; Chen, Xiu-Bo; Yang, Yi-Xian; Wang, Xiaojun

2014-01-01

A difficult problem in quantum network communications is how to efficiently transmit quantum information over large-scale networks with common channels. We propose a solution by developing a quantum encoding approach. Different quantum states are encoded into a coherent superposition state using quantum linear optics. The transmission congestion in the common channel may be avoided by transmitting the superposition state. For further decoding and continued transmission, special phase transformations are applied to incoming quantum states using phase shifters such that decoders can distinguish outgoing quantum states. These phase shifters may be precisely controlled using classical chaos synchronization via additional classical channels. Based on this design and the reduction of multiple-source network under the assumption of restricted maximum-flow, the optimal scheme is proposed for specially quantized multiple-source network. In comparison with previous schemes, our scheme can greatly increase the transmission efficiency. PMID:24691590

Exciton multiplication from first principles.

PubMed

Jaeger, Heather M; Hyeon-Deuk, Kim; Prezhdo, Oleg V

2013-06-18

Third-generation photovolatics require demanding cost and power conversion efficiency standards, which may be achieved through efficient exciton multiplication. Therefore, generating more than one electron-hole pair from the absorption of a single photon has vast ramifications on solar power conversion technology. Unlike their bulk counterparts, irradiated semiconductor quantum dots exhibit efficient exciton multiplication, due to confinement-enhanced Coulomb interactions and slower nonradiative losses. The exact characterization of the complicated photoexcited processes within quantum-dot photovoltaics is a work in progress. In this Account, we focus on the photophysics of nanocrystals and investigate three constituent processes of exciton multiplication, including photoexcitation, phonon-induced dephasing, and impact ionization. We quantify the role of each process in exciton multiplication through ab initio computation and analysis of many-electron wave functions. The probability of observing a multiple exciton in a photoexcited state is proportional to the magnitude of electron correlation, where correlated electrons can be simultaneously promoted across the band gap. Energies of multiple excitons are determined directly from the excited state wave functions, defining the threshold for multiple exciton generation. This threshold is strongly perturbed in the presence of surface defects, dopants, and ionization. Within a few femtoseconds following photoexcitation, the quantum state loses coherence through interactions with the vibrating atomic lattice. The phase relationship between single excitons and multiple excitons dissipates first, followed by multiple exciton fission. Single excitons are coupled to multiple excitons through Coulomb and electron-phonon interactions, and as a consequence, single excitons convert to multiple excitons and vice versa. Here, exciton multiplication depends on the initial energy and coupling magnitude and competes with electron-phonon energy relaxation. Multiple excitons are generated through impact ionization within picoseconds. The basis of exciton multiplication in quantum dots is the collective result of photoexcitation, dephasing, and nonadiabatic evolution. Each process is characterized by a distinct time-scale, and the overall multiple exciton generation dynamics is complete by about 10 ps. Without relying on semiempirical parameters, we computed quantum mechanical probabilities of multiple excitons for small model systems. Because exciton correlations and coherences are microscopic, quantum properties, results for small model systems can be extrapolated to larger, realistic quantum dots.

Characterization of melt-quenched and milled amorphous solids of gatifloxacin.

PubMed

Hattori, Yusuke; Suzuki, Ayumi; Otsuka, Makoto

2016-11-01

The objectives of this study were to characterize and investigate the differences in amorphous states of gatifloxacin. We prepared two types of gatifloxacin amorphous solids coded as M and MQ using milling and melt-quenching methods, respectively. The amorphous solids were characterized via X-ray diffraction (XRD), nonisothermal differential scanning calorimetry (DSC) and time-resolved near-infrared (NIR) spectroscopy. Both the solids displayed halo XRD patterns, the characteristic of amorphous solids; however, in the non-isothermal DSC profiles, these amorphous solids were distinguished by their crystallization and melting temperatures. The Kissinger-Akahira-Sunose plots of non-isothermal crystallization temperatures at various heating rates indicated a lower activation energy of crystallization for the amorphous solid M than that of MQ. These results support the differentiation between two amorphous states with different physical and chemical properties.

Nonadditivity of quantum and classical capacities for entanglement breaking multiple-access channels and the butterfly network

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

Grudka, Andrzej; National Quantum Information Centre of Gdansk, PL-81-824 Sopot; Horodecki, Pawel

2010-06-15

We analyze quantum network primitives which are entanglement breaking. We show superadditivity of quantum and classical capacity regions for quantum multiple-access channels and the quantum butterfly network. Since the effects are especially visible at high noise they suggest that quantum information effects may be particularly helpful in the case of the networks with occasional high noise rates. The present effects provide a qualitative borderline between superadditivities of bipartite and multipartite systems.

Modeling of Air-to-Air Refueling for an Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Spears, Brian Raul

Air-to-air refueling is important to the military for enabling aircraft to remain in the air for long periods of time, reducing the need for forward bases, and allowing aircraft to stay on mission for longer intervals. Although this has been available for traditional military aircraft for several decades, it has not been implemented for the use of Unmanned Aerial Vehicles (UAV). This thesis uses a panel method, VSAERO, to examine the effects that a large tanker aircraft will have on a small unmanned aerial vehicle during a refueling process. The primary cause of conditions behind the tanker aircraft is the wake generated by the wingtip vortices of the aircraft. The planes used for this analysis were an Airbus A320 as the tanker, and a General Atomic MQ-9 as the receiver. The techniques used were to examine literature on aerial refueling, and analyze the aerodynamic characteristics of the UAV. The most important properties that were examined were the rolling moment, pitching moment, and lift. These characteristics were used to determine the feasibility of the UAV being able to withstand the conditions behind the A320. Through the analysis of the MQ-9's aerodynamic characteristics when in ideal conditions, along with its maximum rolling moment, and those same characteristics when flying behind the tanker, it was determined that the MQ-9 would be able to maintain position behind an A320 in order to complete the aerial refueling process.

Reduced CMRO₂ and cerebrovascular reserve in patients with severe intracranial arterial stenosis: a combined multiparametric qBOLD oxygenation and BOLD fMRI study.

PubMed

Bouvier, Julien; Detante, Olivier; Tahon, Florence; Attye, Arnaud; Perret, Thomas; Chechin, David; Barbieux, Marianne; Boubagra, Kamel; Garambois, Katia; Tropres, Irène; Grand, Sylvie; Barbier, Emmanuel L; Krainik, Alexandre

2015-02-01

Multiparametric quantitative blood oxygenation level dependent (mqBOLD) magnetic resonance Imaging (MRI) approach allows mapping tissular oxygen saturation (StO2 ) and cerebral metabolic rate of oxygen (CMRO2 ). To identify hemodynamic alteration related to severe intracranial arterial stenosis (SIAS), functional MRI of cerebrovascular reserve (CVR BOLD fMRI) to hypercapnia has been proposed. Diffusion imaging suggests chronic low grade ischemia in patients with impaired CVR. The aim of the present study was to evaluate how oxygen parameters (StO2 and CMRO2 ), assessed with mqBOLD approach, correlate with CVR in patients (n = 12) with SIAS and without arterial occlusion. The perfusion (dynamic susceptibility contrast), oxygenation, and CVR were compared. The MRI protocol conducted at 3T lasted approximately 1 h. Regions of interest measures on maps were delineated on segmented gray matter (GM) of middle cerebral artery territories. We have shown that decreased CVR is spatially associated with decreased CMRO2 in GM of patients with SIAS. Further, the degree of ipsilateral CVR reduction was well-correlated with the amplitude of the CMRO2 deficit. The altered CMRO2 suggests the presence of a moderate ischemia explained by both a decrease in perfusion and in CVR. CVR and mqBOLD method may be helpful in the selection of patients with SIAS to advocate for medical therapy or percutaneous transluminal angioplasty-stenting. © 2014 Wiley Periodicals, Inc.

Multiple-state quantum Otto engine, 1D box system

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

Latifah, E., E-mail: enylatifah@um.ac.id; Purwanto, A.

2014-03-24

Quantum heat engines produce work using quantum matter as their working substance. We studied adiabatic and isochoric processes and defined the general force according to quantum system. The processes and general force are used to evaluate a quantum Otto engine based on multiple-state of one dimensional box system and calculate the efficiency. As a result, the efficiency depends on the ratio of initial and final width of system under adiabatic processes.

An efficient quantum circuit analyser on qubits and qudits

NASA Astrophysics Data System (ADS)

Loke, T.; Wang, J. B.

2011-10-01

This paper presents a highly efficient decomposition scheme and its associated Mathematica notebook for the analysis of complicated quantum circuits comprised of single/multiple qubit and qudit quantum gates. In particular, this scheme reduces the evaluation of multiple unitary gate operations with many conditionals to just two matrix additions, regardless of the number of conditionals or gate dimensions. This improves significantly the capability of a quantum circuit analyser implemented in a classical computer. This is also the first efficient quantum circuit analyser to include qudit quantum logic gates.

Optical properties of a-plane (Al, Ga)N/GaN multiple quantum wells grown on strain engineered Zn1-xMgxO layers by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Xia, Y.; Brault, J.; Nemoz, M.; Teisseire, M.; Vinter, B.; Leroux, M.; Chauveau, J.-M.

2011-12-01

Nonpolar (112¯0) Al0.2Ga0.8N/GaN multiple quantum wells (MQWs) have been grown by molecular beam epitaxy on (112¯0) Zn0.74Mg0.26O templates on r-plane sapphire substrates. The quantum wells exhibit well-resolved photoluminescence peaks in the ultra-violet region, and no sign of quantum confined Stark effect is observed in the complete multiple quantum well series. The results agree well with flat band quantum well calculations. Furthermore, we show that the MQW structures are strongly polarized along the [0001] direction. The origin of the polarization is discussed in terms of the strain anisotropy dependence of the exciton optical oscillator strengths.

Critical side channel effects in random bit generation with multiple semiconductor lasers in a polarization-based quantum key distribution system.

PubMed

Ko, Heasin; Choi, Byung-Seok; Choe, Joong-Seon; Kim, Kap-Joong; Kim, Jong-Hoi; Youn, Chun Ju

2017-08-21

Most polarization-based BB84 quantum key distribution (QKD) systems utilize multiple lasers to generate one of four polarization quantum states randomly. However, random bit generation with multiple lasers can potentially open critical side channels that significantly endangers the security of QKD systems. In this paper, we show unnoticed side channels of temporal disparity and intensity fluctuation, which possibly exist in the operation of multiple semiconductor laser diodes. Experimental results show that the side channels can enormously degrade security performance of QKD systems. An important system issue for the improvement of quantum bit error rate (QBER) related with laser driving condition is further addressed with experimental results.

Quantum theory of multiple-input-multiple-output Markovian feedback with diffusive measurements

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

Chia, A.; Wiseman, H. M.

2011-07-15

Feedback control engineers have been interested in multiple-input-multiple-output (MIMO) extensions of single-input-single-output (SISO) results of various kinds due to its rich mathematical structure and practical applications. An outstanding problem in quantum feedback control is the extension of the SISO theory of Markovian feedback by Wiseman and Milburn [Phys. Rev. Lett. 70, 548 (1993)] to multiple inputs and multiple outputs. Here we generalize the SISO homodyne-mediated feedback theory to allow for multiple inputs, multiple outputs, and arbitrary diffusive quantum measurements. We thus obtain a MIMO framework which resembles the SISO theory and whose additional mathematical structure is highlighted by the extensivemore » use of vector-operator algebra.« less

Multiple-exciton generation in lead selenide nanorod solar cells with external quantum efficiencies exceeding 120%

PubMed Central

Davis, Nathaniel J. L. K.; Böhm, Marcus L.; Tabachnyk, Maxim; Wisnivesky-Rocca-Rivarola, Florencia; Jellicoe, Tom C.; Ducati, Caterina; Ehrler, Bruno; Greenham, Neil C.

2015-01-01

Multiple-exciton generation—a process in which multiple charge-carrier pairs are generated from a single optical excitation—is a promising way to improve the photocurrent in photovoltaic devices and offers the potential to break the Shockley–Queisser limit. One-dimensional nanostructures, for example nanorods, have been shown spectroscopically to display increased multiple exciton generation efficiencies compared with their zero-dimensional analogues. Here we present solar cells fabricated from PbSe nanorods of three different bandgaps. All three devices showed external quantum efficiencies exceeding 100% and we report a maximum external quantum efficiency of 122% for cells consisting of the smallest bandgap nanorods. We estimate internal quantum efficiencies to exceed 150% at relatively low energies compared with other multiple exciton generation systems, and this demonstrates the potential for substantial improvements in device performance due to multiple exciton generation. PMID:26411283

A DFT investigation on geometry and chemical bonding of isoelectronic Si8N6V-, Si8N6Cr, and Si8N6Mn+ clusters

NASA Astrophysics Data System (ADS)

Tam, Nguyen Minh; Pham, Hung Tan; Cuong, Ngo Tuan; Tung, Nguyen Thanh

2017-10-01

The geometric feature and chemical bonding of isoelectronic systems Si8N6Mq (M = V, Cr, Mn and q = -1, 0, 1, respectively) are investigated by means of density-functional-theory calculations. The encapsulated form is found for all ground-state structures, where the metal atom locates at the central site of the hollow Si8N6 cage. The Si8N6 cage is established by adding two Si atoms to a distorted Si6N6 prism, which is a combination of Si4N2 and Si2N4 strings. Chemical bonding of Si8N6Mq systems is explored by using the electron localization indicator and theory of atom in molecule, revealing the vital role of metal center in stabilizing the clusters.

The WLCG Messaging Service and its Future

NASA Astrophysics Data System (ADS)

Cons, Lionel; Paladin, Massimo

2012-12-01

Enterprise messaging is seen as an attractive mechanism to simplify and extend several portions of the Grid middleware, from low level monitoring to experiments dashboards. The production messaging service currently used by WLCG includes four tightly coupled brokers operated by EGI (running Apache ActiveMQ and designed to host the Grid operational tools such as SAM) as well as two dedicated services for ATLAS-DDM and experiments dashboards (currently also running Apache ActiveMQ). In the future, this service is expected to grow in numbers of applications supported, brokers and technologies. The WLCG Messaging Roadmap identified three areas with room for improvement (security, scalability and availability/reliability) as well as ten practical recommendations to address them. This paper describes a messaging service architecture that is in line with these recommendations as well as a software architecture based on reusable components that ease interactions with the messaging service. These two architectures will support the growth of the WLCG messaging service.

MESSENGER observations of the composition of Mercury's ionized exosphere and plasma environment.

PubMed

Zurbuchen, Thomas H; Raines, Jim M; Gloeckler, George; Krimigis, Stamatios M; Slavin, James A; Koehn, Patrick L; Killen, Rosemary M; Sprague, Ann L; McNutt, Ralph L; Solomon, Sean C

2008-07-04

The region around Mercury is filled with ions that originate from interactions of the solar wind with Mercury's space environment and through ionization of its exosphere. The MESSENGER spacecraft's observations of Mercury's ionized exosphere during its first flyby yielded Na+, O+, and K+ abundances, consistent with expectations from observations of neutral species. There are increases in ions at a mass per charge (m/q) = 32 to 35, which we interpret to be S+ and H2S+, with (S+ + H2S+)/(Na+ + Mg+) = 0.67 +/- 0.06, and from water-group ions around m/q = 18, at an abundance of 0.20 +/- 0.03 relative to Na+ plus Mg+. The fluxes of Na+, O+, and heavier ions are largest near the planet, but these Mercury-derived ions fill the magnetosphere. Doubly ionized ions originating from Mercury imply that electrons with energies less than 1 kiloelectron volt are substantially energized in Mercury's magnetosphere.

Double Parton Fragmentation Function and its Evolution in Quarkonium Production

NASA Astrophysics Data System (ADS)

Kang, Zhong-Bo

2014-01-01

We summarize the results of a recent study on a new perturbative QCD factorization formalism for the production of heavy quarkonia of large transverse momentum pT at collider energies. Such a new factorization formalism includes both the leading power (LP) and next-to-leading power (NLP) contributions to the cross section in the mQ2/p_T^2 expansion for heavy quark mass mQ. For the NLP contribution, the so-called double parton fragmentation functions are involved, whose evolution equations have been derived. We estimate fragmentation functions in the non-relativistic QCD formalism, and found that their contribution reproduce the bulk of the large enhancement found in explicit NLO calculations in the color singlet model. Heavy quarkonia produced from NLP channels prefer longitudinal polarization, in contrast to the single parton fragmentation function. This might shed some light on the heavy quarkonium polarization puzzle.

Storage of multiple single-photon pulses emitted from a quantum dot in a solid-state quantum memory.

PubMed

Tang, Jian-Shun; Zhou, Zong-Quan; Wang, Yi-Tao; Li, Yu-Long; Liu, Xiao; Hua, Yi-Lin; Zou, Yang; Wang, Shuang; He, De-Yong; Chen, Geng; Sun, Yong-Nan; Yu, Ying; Li, Mi-Feng; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Li, Chuan-Feng; Guo, Guang-Can

2015-10-15

Quantum repeaters are critical components for distributing entanglement over long distances in presence of unavoidable optical losses during transmission. Stimulated by the Duan-Lukin-Cirac-Zoller protocol, many improved quantum repeater protocols based on quantum memories have been proposed, which commonly focus on the entanglement-distribution rate. Among these protocols, the elimination of multiple photons (or multiple photon-pairs) and the use of multimode quantum memory are demonstrated to have the ability to greatly improve the entanglement-distribution rate. Here, we demonstrate the storage of deterministic single photons emitted from a quantum dot in a polarization-maintaining solid-state quantum memory; in addition, multi-temporal-mode memory with 1, 20 and 100 narrow single-photon pulses is also demonstrated. Multi-photons are eliminated, and only one photon at most is contained in each pulse. Moreover, the solid-state properties of both sub-systems make this configuration more stable and easier to be scalable. Our work will be helpful in the construction of efficient quantum repeaters based on all-solid-state devices.

Storage of multiple single-photon pulses emitted from a quantum dot in a solid-state quantum memory

PubMed Central

Tang, Jian-Shun; Zhou, Zong-Quan; Wang, Yi-Tao; Li, Yu-Long; Liu, Xiao; Hua, Yi-Lin; Zou, Yang; Wang, Shuang; He, De-Yong; Chen, Geng; Sun, Yong-Nan; Yu, Ying; Li, Mi-Feng; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Li, Chuan-Feng; Guo, Guang-Can

2015-01-01

Quantum repeaters are critical components for distributing entanglement over long distances in presence of unavoidable optical losses during transmission. Stimulated by the Duan–Lukin–Cirac–Zoller protocol, many improved quantum repeater protocols based on quantum memories have been proposed, which commonly focus on the entanglement-distribution rate. Among these protocols, the elimination of multiple photons (or multiple photon-pairs) and the use of multimode quantum memory are demonstrated to have the ability to greatly improve the entanglement-distribution rate. Here, we demonstrate the storage of deterministic single photons emitted from a quantum dot in a polarization-maintaining solid-state quantum memory; in addition, multi-temporal-mode memory with 1, 20 and 100 narrow single-photon pulses is also demonstrated. Multi-photons are eliminated, and only one photon at most is contained in each pulse. Moreover, the solid-state properties of both sub-systems make this configuration more stable and easier to be scalable. Our work will be helpful in the construction of efficient quantum repeaters based on all-solid-state devices. PMID:26468996

Rapid response of a marine mammal species to holocene climate and habitat change.

PubMed

de Bruyn, Mark; Hall, Brenda L; Chauke, Lucas F; Baroni, Carlo; Koch, Paul L; Hoelzel, A Rus

2009-07-01

Environmental change drives demographic and evolutionary processes that determine diversity within and among species. Tracking these processes during periods of change reveals mechanisms for the establishment of populations and provides predictive data on response to potential future impacts, including those caused by anthropogenic climate change. Here we show how a highly mobile marine species responded to the gain and loss of new breeding habitat. Southern elephant seal, Mirounga leonina, remains were found along the Victoria Land Coast (VLC) in the Ross Sea, Antarctica, 2,500 km from the nearest extant breeding site on Macquarie Island (MQ). This habitat was released after retreat of the grounded ice sheet in the Ross Sea Embayment 7,500-8,000 cal YBP, and is within the range of modern foraging excursions from the MQ colony. Using ancient mtDNA and coalescent models, we tracked the population dynamics of the now extinct VLC colony and the connectivity between this and extant breeding sites. We found a clear expansion signal in the VLC population approximately 8,000 YBP, followed by directional migration away from VLC and the loss of diversity at approximately 1,000 YBP, when sea ice is thought to have expanded. Our data suggest that VLC seals came initially from MQ and that some returned there once the VLC habitat was lost, approximately 7,000 years later. We track the founder-extinction dynamics of a population from inception to extinction in the context of Holocene climate change and present evidence that an unexpectedly diverse, differentiated breeding population was founded from a distant source population soon after habitat became available.

Plasmon-Assisted Selective and Super-Resolving Excitation of Individual Quantum Emitters on a Metal Nanowire.

PubMed

Li, Qiang; Pan, Deng; Wei, Hong; Xu, Hongxing

2018-03-14

Hybrid systems composed of multiple quantum emitters coupled with plasmonic waveguides are promising building blocks for future integrated quantum nanophotonic circuits. The techniques that can super-resolve and selectively excite contiguous quantum emitters in a diffraction-limited area are of great importance for studying the plasmon-mediated interaction between quantum emitters and manipulating the single plasmon generation and propagation in plasmonic circuits. Here we show that multiple quantum dots coupled with a silver nanowire can be controllably excited by tuning the interference field of surface plasmons on the nanowire. Because of the period of the interference pattern is much smaller than the diffraction limit, we demonstrate the selective excitation of two quantum dots separated by a distance as short as 100 nm. We also numerically demonstrate a new kind of super-resolution imaging method that combines the tunable surface plasmon interference pattern on the NW with the structured illumination microscopy technique. Our work provides a novel high-resolution optical excitation and imaging method for the coupled systems of multiple quantum emitters and plasmonic waveguides, which adds a new tool for studying and manipulating single quantum emitters and single plasmons for quantum plasmonic circuitry applications.

Spiral Plating Method To Quantify the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces.

PubMed

Shridhar, Pragathi B; Noll, Lance W; Cull, Charley A; Shi, Xiaorong; Cernicchiaro, Natalia; Renter, David G; Bai, Jianfa; Nagaraja, T G

2017-04-17

Cattle are a major reservoir of the six major Shiga toxin-producing non-O157 Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) responsible for foodborne illnesses in humans. Besides prevalence in feces, the concentrations of STEC in cattle feces play a major role in their transmission dynamics. A subset of cattle, referred to as super shedders, shed E. coli O157 at high concentrations (≥4 log CFU/g of feces). It is not known whether a similar pattern of fecal shedding exists for non-O157. Our objectives were to initially validate the spiral plating method to quantify the six non-O157 E. coli serogroups with pure cultures and culture-spiked fecal samples and then determine the applicability of the method and compare it with multiplex quantitative PCR (mqPCR) assays for the quantification of the six non-O157 E. coli serogroups in cattle fecal samples collected from commercial feedlots. Quantification limits of the spiral plating method were 3 log, 3 to 4 log, and 3 to 5 log CFU/mL or CFU/g for individual cultures, pooled pure cultures, and cattle fecal samples spiked with pooled pure cultures, respectively. Of the 1,152 cattle fecal samples tested from eight commercial feedlots, 122 (10.6%) and 320 (27.8%) harbored concentrations ≥4 log CFU/g of one or more of the six serogroups of non-O157 by spiral plating and mqPCR methods, respectively. A majority of quantifiable samples, detected by either spiral plating (135 of 137, 98.5%) or mqPCR (239 of 320, 74.7%), were shedding only one serogroup. Only one of the quantifiable samples was positive for a serogroup carrying Shiga toxin (stx 1 ) and intimin (eae) genes; 38 samples were positive for serogroups carrying the intimin gene. In conclusion, the spiral plating method can be used to quantify non-O157 serogroups in cattle feces, and our study identified a subset of cattle that was super shedders of non-O157 E. coli . The method has the advantage of quantifying non-O157 STEC, unlike mqPCR that quantifies serogroups only.

Risks of Hemolysis in Glucose-6-Phosphate Dehydrogenase Deficient Infants Exposed to Chlorproguanil-Dapsone, Mefloquine and Sulfadoxine-Pyrimethamine as Part of Intermittent Presumptive Treatment of Malaria in Infants.

PubMed

Poirot, Eugenie; Vittinghoff, Eric; Ishengoma, Deus; Alifrangis, Michael; Carneiro, Ilona; Hashim, Ramadhan; Baraka, Vito; Mosha, Jacklin; Gesase, Samwel; Chandramohan, Daniel; Gosling, Roland

2015-01-01

Chlorproguanil-dapsone (CD) has been linked to hemolysis in symptomatic glucose-6-phosphate dehydrogenase deficient (G6PDd) children. Few studies have explored the effects of G6PD status on hemolysis in children treated with Intermittent Preventive Treatment in infants (IPTi) antimalarial regimens. We sought to examine the joint effects of G6PD status and IPTi antimalarial treatment on incidence of hemolysis in asymptomatic children treated with CD, sulfadoxine-pyrimethamine (SP), and mefloquine (MQ). A secondary analysis of data from a double-blind, placebo-controlled trial of IPTi was conducted. Hemoglobin (Hb) measurements were made at IPTi doses, regular follow-up and emergency visits. G6PD genotype was determined at 9 months looking for SNPs for the A- genotype at coding position 202. Multivariable linear and logistic regression models were used to examine hemolysis among children with valid G6PD genotyping results. Hemolysis was defined as the absolute change in Hb or as any post-dose Hb <8 g/dL. These outcomes were assessed using either a single follow-up Hb on day 7 after an IPTi dose or Hb obtained 1 to 14 or 28 days after each IPTi dose. Relative to placebo, CD reduced Hb by approximately 0.5 g/dL at day 7 and within 14 days of an IPTi dose, and by 0.2 g/dL within 28 days. Adjusted declines in the CD group were larger than in the MQ and SP groups. At day 7, homo-/hemizygous genotype was associated with higher odds of Hb <8 g/dL (adjusted odds ratio = 6.7, 95% CI 1.7 to 27.0) and greater absolute reductions in Hb (-0.6 g/dL, 95% CI -1.1 to 0.003). There was no evidence to suggest increased reductions in Hb among homo-/hemizygous children treated with CD compared to placebo, SP or MQ. While treatment with CD demonstrated greater reductions in Hb at 7 and 14 days after an IPTi dose compared to both SP and MQ, there was no evidence that G6PD deficiency exacerbated the adverse effects of CD, despite evidence for higher hemolysis risk among G6PDd infants.

Multiple quantum coherence spectroscopy.

PubMed

Mathew, Nathan A; Yurs, Lena A; Block, Stephen B; Pakoulev, Andrei V; Kornau, Kathryn M; Wright, John C

2009-08-20

Multiple quantum coherences provide a powerful approach for studies of complex systems because increasing the number of quantum states in a quantum mechanical superposition state increases the selectivity of a spectroscopic measurement. We show that frequency domain multiple quantum coherence multidimensional spectroscopy can create these superposition states using different frequency excitation pulses. The superposition state is created using two excitation frequencies to excite the symmetric and asymmetric stretch modes in a rhodium dicarbonyl chelate and the dynamic Stark effect to climb the vibrational ladders involving different overtone and combination band states. A monochromator resolves the free induction decay of different coherences comprising the superposition state. The three spectral dimensions provide the selectivity required to observe 19 different spectral features associated with fully coherent nonlinear processes involving up to 11 interactions with the excitation fields. The different features act as spectroscopic probes of the diagonal and off-diagonal parts of the molecular potential energy hypersurface. This approach can be considered as a coherent pump-probe spectroscopy where the pump is a series of excitation pulses that prepares a multiple quantum coherence and the probe is another series of pulses that creates the output coherence.

76 FR 34124 - Civil Supersonic Aircraft Panel Discussion

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-10

... and continuing to the second line in the second column, the Web site address should read as follows: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dEFEdlRnYzBiaHZtTUozTHVtbkF4d0E6MQ . [FR...

Luminescence of quantum-well exciton polaritons from microstructured AlxGa1-xAs-GaAs multiple quantum wells

NASA Astrophysics Data System (ADS)

Kohl, M.; Heitmann, D.; Grambow, P.; Ploog, K.

1988-06-01

Periodic multiple-quantum-well wires have been prepared by etching five-layer quantum-well structures through a holographically prepared mask. The periodicity was 380 nm, the lateral confinement 180 nm, and the quantum-well width 13, nm. The luminescence from these microstructured systems in the frequency regime of the one-electron-one-heavy-hole transition was strongly polarized with the electric field perpendicular to the periodic structure. This effect was caused by the resonantly enhanced emission of quantum-well-exciton (QWE) polaritons. Excitation of QWE polaritons was also observed in reflection measurements on the microstructured samples.

On-chip coherent conversion of photonic quantum entanglement between different degrees of freedom

PubMed Central

Feng, Lan-Tian; Zhang, Ming; Zhou, Zhi-Yuan; Li, Ming; Xiong, Xiao; Yu, Le; Shi, Bao-Sen; Guo, Guo-Ping; Dai, Dao-Xin; Ren, Xi-Feng; Guo, Guang-Can

2016-01-01

In the quantum world, a single particle can have various degrees of freedom to encode quantum information. Controlling multiple degrees of freedom simultaneously is necessary to describe a particle fully and, therefore, to use it more efficiently. Here we introduce the transverse waveguide-mode degree of freedom to quantum photonic integrated circuits, and demonstrate the coherent conversion of a photonic quantum state between path, polarization and transverse waveguide-mode degrees of freedom on a single chip. The preservation of quantum coherence in these conversion processes is proven by single-photon and two-photon quantum interference using a fibre beam splitter or on-chip beam splitters. These results provide us with the ability to control and convert multiple degrees of freedom of photons for quantum photonic integrated circuit-based quantum information process. PMID:27321821

On-chip coherent conversion of photonic quantum entanglement between different degrees of freedom.

PubMed

Feng, Lan-Tian; Zhang, Ming; Zhou, Zhi-Yuan; Li, Ming; Xiong, Xiao; Yu, Le; Shi, Bao-Sen; Guo, Guo-Ping; Dai, Dao-Xin; Ren, Xi-Feng; Guo, Guang-Can

2016-06-20

In the quantum world, a single particle can have various degrees of freedom to encode quantum information. Controlling multiple degrees of freedom simultaneously is necessary to describe a particle fully and, therefore, to use it more efficiently. Here we introduce the transverse waveguide-mode degree of freedom to quantum photonic integrated circuits, and demonstrate the coherent conversion of a photonic quantum state between path, polarization and transverse waveguide-mode degrees of freedom on a single chip. The preservation of quantum coherence in these conversion processes is proven by single-photon and two-photon quantum interference using a fibre beam splitter or on-chip beam splitters. These results provide us with the ability to control and convert multiple degrees of freedom of photons for quantum photonic integrated circuit-based quantum information process.

Quantum Double of Yangian of strange Lie superalgebra Qn and multiplicative formula for universal R-matrix

NASA Astrophysics Data System (ADS)

Stukopin, Vladimir

2018-02-01

Main result is the multiplicative formula for universal R-matrix for Quantum Double of Yangian of strange Lie superalgebra Qn type. We introduce the Quantum Double of the Yangian of the strange Lie superalgebra Qn and define its PBW basis. We compute the Hopf pairing for the generators of the Yangian Double. From the Hopf pairing formulas we derive a factorized multiplicative formula for the universal R-matrix of the Yangian Double of the Lie superalgebra Qn . After them we obtain coefficients in this multiplicative formula for universal R-matrix.

Effects of quantum well growth temperature on the recombination efficiency of InGaN/GaN multiple quantum wells that emit in the green and blue spectral regions

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

Hammersley, S.; Dawson, P.; Kappers, M. J.

2015-09-28

InGaN-based light emitting diodes and multiple quantum wells designed to emit in the green spectral region exhibit, in general, lower internal quantum efficiencies than their blue-emitting counter parts, a phenomenon referred to as the “green gap.” One of the main differences between green-emitting and blue-emitting samples is that the quantum well growth temperature is lower for structures designed to emit at longer wavelengths, in order to reduce the effects of In desorption. In this paper, we report on the impact of the quantum well growth temperature on the optical properties of InGaN/GaN multiple quantum wells designed to emit at 460 nmmore » and 530 nm. It was found that for both sets of samples increasing the temperature at which the InGaN quantum well was grown, while maintaining the same indium composition, led to an increase in the internal quantum efficiency measured at 300 K. These increases in internal quantum efficiency are shown to be due reductions in the non-radiative recombination rate which we attribute to reductions in point defect incorporation.« less

Frequency doubling of an InGaAs multiple quantum wells semiconductor disk laser

NASA Astrophysics Data System (ADS)

Lidan, Jiang; Renjiang, Zhu; Maohua, Jiang; Dingke, Zhang; Yuting, Cui; Peng, Zhang; Yanrong, Song

2018-01-01

We demonstrate a good beam quality 483 nm blue coherent radiation from a frequency doubled InGaAs multiple quantum wells semiconductor disk laser. The gain chip is consisted of 6 repeats of strain uncompensated InGaAs/GaAs quantum wells and 25 pairs of GaAs/AlAs distributed Bragg reflector. A 4 × 4 × 7 mm3 type I phase-matched BBO nonlinear crystal is used in a V-shaped laser cavity for the second harmonic generation, and 210 mW blue output power is obtained when the absorbed pump power is 3.5 W. The M2 factors of the laser beam in x and y directions are about 1.04 and 1.01, respectively. The output power of the blue laser is limited by the relatively small number of the multiple quantum wells, and higher power can be expected by increasing the number of the multiple quantum wells and improving the heat management of the laser.

Quantum Sets and Clifford Algebras

NASA Astrophysics Data System (ADS)

Finkelstein, David

1982-06-01

The mathematical language presently used for quantum physics is a high-level language. As a lowest-level or basic language I construct a quantum set theory in three stages: (1) Classical set theory, formulated as a Clifford algebra of “ S numbers” generated by a single monadic operation, “bracing,” Br = {…}. (2) Indefinite set theory, a modification of set theory dealing with the modal logical concept of possibility. (3) Quantum set theory. The quantum set is constructed from the null set by the familiar quantum techniques of tensor product and antisymmetrization. There are both a Clifford and a Grassmann algebra with sets as basis elements. Rank and cardinality operators are analogous to Schroedinger coordinates of the theory, in that they are multiplication or “ Q-type” operators. “ P-type” operators analogous to Schroedinger momenta, in that they transform the Q-type quantities, are bracing (Br), Clifford multiplication by a set X, and the creator of X, represented by Grassmann multiplication c( X) by the set X. Br and its adjoint Br* form a Bose-Einstein canonical pair, and c( X) and its adjoint c( X)* form a Fermi-Dirac or anticanonical pair. Many coefficient number systems can be employed in this quantization. I use the integers for a discrete quantum theory, with the usual complex quantum theory as limit. Quantum set theory may be applied to a quantum time space and a quantum automaton.

Rapid Response of a Marine Mammal Species to Holocene Climate and Habitat Change

PubMed Central

de Bruyn, Mark; Hall, Brenda L.; Chauke, Lucas F.; Baroni, Carlo; Koch, Paul L.; Hoelzel, A. Rus

2009-01-01

Environmental change drives demographic and evolutionary processes that determine diversity within and among species. Tracking these processes during periods of change reveals mechanisms for the establishment of populations and provides predictive data on response to potential future impacts, including those caused by anthropogenic climate change. Here we show how a highly mobile marine species responded to the gain and loss of new breeding habitat. Southern elephant seal, Mirounga leonina, remains were found along the Victoria Land Coast (VLC) in the Ross Sea, Antarctica, 2,500 km from the nearest extant breeding site on Macquarie Island (MQ). This habitat was released after retreat of the grounded ice sheet in the Ross Sea Embayment 7,500–8,000 cal YBP, and is within the range of modern foraging excursions from the MQ colony. Using ancient mtDNA and coalescent models, we tracked the population dynamics of the now extinct VLC colony and the connectivity between this and extant breeding sites. We found a clear expansion signal in the VLC population ∼8,000 YBP, followed by directional migration away from VLC and the loss of diversity at ∼1,000 YBP, when sea ice is thought to have expanded. Our data suggest that VLC seals came initially from MQ and that some returned there once the VLC habitat was lost, ∼7,000 years later. We track the founder-extinction dynamics of a population from inception to extinction in the context of Holocene climate change and present evidence that an unexpectedly diverse, differentiated breeding population was founded from a distant source population soon after habitat became available. PMID:19593366

Hydration effects on the electronic properties of eumelanin building blocks

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

Assis Oliveira, Leonardo Bruno; Departamento de Física - CEPAE, Universidade Federal de Goiás, 74690-900 Goiânia, GO; Escola de Ciências Exatas e da Computação, Pontifícia Universidade Católica de Goiás, 74605-010 Goiânia, GO

2016-08-28

Theoretical results for the electronic properties of eumelanin building blocks in the gas phase and water are presented. The building blocks presently investigated include the monomeric species DHI (5,6-dihydroxyindole) or hydroquinone (HQ), DHICA (5,6-dihydroxyindole-2-carboxylic acid), indolequinone (IQ), quinone methide (MQ), two covalently bonded dimers [HM ≡ HQ + MQ and IM ≡ IQ + MQ], and two tetramers [HMIM ≡ HQ + IM, IMIM ≡ IM + IM]. The electronic properties in water were determined by carrying out sequential Monte Carlo/time dependent density functional theory calculations. The results illustrate the role played by hydrogen bonding and electrostatic interactions in themore » electronic properties of eumelanin building blocks in a polar environment. In water, the dipole moments of monomeric species are significantly increased ([54–79]%) relative to their gas phase values. Recently, it has been proposed that the observed enhancement of the higher-energy absorption intensity in eumelanin can be explained by excitonic coupling among eumelanin protomolecules [C.-T. Chen et al., Nat. Commun. 5, 3859 (2014)]. Here, we are providing evidence that for DHICA, IQ, and HMIM, the electronic absorption toward the higher-energy end of the spectrum ([180–220] nm) is enhanced by long-range Coulombic interactions with the water environment. It was verified that by superposing the absorption spectra of different eumelanin building blocks corresponding to the monomers, dimers, and tetramers in liquid water, the behaviour of the experimental spectrum, which is characterised by a nearly monotonic decay from the ultraviolet to the infrared, is qualitatively reproduced. This result is in keeping with a “chemical disorder model,” where the broadband absorption of eumelanin pigments is determined by the superposition of the spectra associated with the monomeric and oligomeric building blocks.« less

Qatar Exoplanet Survey : Qatar-3b, Qatar-4b, and Qatar-5b

NASA Astrophysics Data System (ADS)

Alsubai, Khalid; Mislis, Dimitris; Tsvetanov, Zlatan I.; Latham, David W.; Bieryla, Allyson; Buchhave, Lars A.; Esquerdo, Gilbert A.; Bramich, D. M.; Pyrzas, Stylianos; Vilchez, Nicolas P. E.; Mancini, Luigi; Southworth, John; Evans, Daniel F.; Henning, Thomas; Ciceri, Simona

2017-04-01

We report the discovery of Qatar-3b, Qatar-4b, and Qatar-5b, three new transiting planets identified by the Qatar Exoplanet Survey. The three planets belong to the hot Jupiter family, with orbital periods of {P}{{Q}3{{b}}} = 2.50792 days, {P}{{Q}4{{b}}} = 1.80539 days, and {P}{{Q}5{{b}}} = 2.87923 days. Follow-up spectroscopic observations reveal the masses of the planets to be {M}{{Q}3{{b}}} = 4.31 ± 0.47 {M}{{J}}, {M}{{Q}4{{b}}} = 6.10 ± 0.54 {M}{{J}}, and {M}{{Q}5{{b}}} = 4.32 ± 0.18 {M}{{J}}, while model fits to the transit light curves yield radii of {R}{{Q}3{{b}}} = 1.096 ± 0.14 {R}{{J}}, {R}{{Q}4{{b}}} = 1.135 ± 0.11 {R}{{J}}, and {R}{{Q}5{{b}}} = 1.107 ± 0.064 {R}{{J}}. The host stars are low-mass main sequence stars with masses and radii M Q3 = 1.145 ± 0.064 M ⊙, M Q4 = 0.896 ± 0.048 M ⊙, M Q5 = 1.128 ± 0.056 M ⊙ and R Q3 = 1.272 ± 0.14 R ⊙, R Q4 = 0.849 ± 0.063 R ⊙, and R Q5 = 1.076 ± 0.051 R ⊙ for Qatar-3, 4, and 5 respectively. The V magnitudes of the three host stars are V Q3 = 12.88, V Q4 = 13.60, and V Q5 = 12.82. All three new planets can be classified as heavy hot Jupiters (M > 4 M J).

Hydration effects on the electronic properties of eumelanin building blocks.

PubMed

Assis Oliveira, Leonardo Bruno; L Fonseca, Tertius; Costa Cabral, Benedito J; Coutinho, Kaline; Canuto, Sylvio

2016-08-28

Theoretical results for the electronic properties of eumelanin building blocks in the gas phase and water are presented. The building blocks presently investigated include the monomeric species DHI (5,6-dihydroxyindole) or hydroquinone (HQ), DHICA (5,6-dihydroxyindole-2-carboxylic acid), indolequinone (IQ), quinone methide (MQ), two covalently bonded dimers [HM ≡ HQ + MQ and IM ≡ IQ + MQ], and two tetramers [HMIM ≡ HQ + IM, IMIM ≡ IM + IM]. The electronic properties in water were determined by carrying out sequential Monte Carlo/time dependent density functional theory calculations. The results illustrate the role played by hydrogen bonding and electrostatic interactions in the electronic properties of eumelanin building blocks in a polar environment. In water, the dipole moments of monomeric species are significantly increased ([54-79]%) relative to their gas phase values. Recently, it has been proposed that the observed enhancement of the higher-energy absorption intensity in eumelanin can be explained by excitonic coupling among eumelanin protomolecules [C.-T. Chen et al., Nat. Commun. 5, 3859 (2014)]. Here, we are providing evidence that for DHICA, IQ, and HMIM, the electronic absorption toward the higher-energy end of the spectrum ([180-220] nm) is enhanced by long-range Coulombic interactions with the water environment. It was verified that by superposing the absorption spectra of different eumelanin building blocks corresponding to the monomers, dimers, and tetramers in liquid water, the behaviour of the experimental spectrum, which is characterised by a nearly monotonic decay from the ultraviolet to the infrared, is qualitatively reproduced. This result is in keeping with a "chemical disorder model," where the broadband absorption of eumelanin pigments is determined by the superposition of the spectra associated with the monomeric and oligomeric building blocks.

Hydration effects on the electronic properties of eumelanin building blocks

NASA Astrophysics Data System (ADS)

Assis Oliveira, Leonardo Bruno; L. Fonseca, Tertius; Costa Cabral, Benedito J.; Coutinho, Kaline; Canuto, Sylvio

2016-08-01

Theoretical results for the electronic properties of eumelanin building blocks in the gas phase and water are presented. The building blocks presently investigated include the monomeric species DHI (5,6-dihydroxyindole) or hydroquinone (HQ), DHICA (5,6-dihydroxyindole-2-carboxylic acid), indolequinone (IQ), quinone methide (MQ), two covalently bonded dimers [HM ≡ HQ + MQ and IM ≡ IQ + MQ], and two tetramers [HMIM ≡ HQ + IM, IMIM ≡ IM + IM]. The electronic properties in water were determined by carrying out sequential Monte Carlo/time dependent density functional theory calculations. The results illustrate the role played by hydrogen bonding and electrostatic interactions in the electronic properties of eumelanin building blocks in a polar environment. In water, the dipole moments of monomeric species are significantly increased ([54-79]%) relative to their gas phase values. Recently, it has been proposed that the observed enhancement of the higher-energy absorption intensity in eumelanin can be explained by excitonic coupling among eumelanin protomolecules [C.-T. Chen et al., Nat. Commun. 5, 3859 (2014)]. Here, we are providing evidence that for DHICA, IQ, and HMIM, the electronic absorption toward the higher-energy end of the spectrum ([180-220] nm) is enhanced by long-range Coulombic interactions with the water environment. It was verified that by superposing the absorption spectra of different eumelanin building blocks corresponding to the monomers, dimers, and tetramers in liquid water, the behaviour of the experimental spectrum, which is characterised by a nearly monotonic decay from the ultraviolet to the infrared, is qualitatively reproduced. This result is in keeping with a "chemical disorder model," where the broadband absorption of eumelanin pigments is determined by the superposition of the spectra associated with the monomeric and oligomeric building blocks.

Ex Vivo Susceptibility of Plasmodium falciparum to Antimalarial Drugs in Western, Northern, and Eastern Cambodia, 2011-2012: Association with Molecular Markers

PubMed Central

Lim, Pharath; Dek, Dalin; Try, Vorleak; Eastman, Richard T.; Chy, Sophy; Sreng, Sokunthea; Suon, Seila; Mao, Sivanna; Sopha, Chantha; Sam, Baramey; Ashley, Elizabeth A.; Miotto, Olivo; Dondorp, Arjen M.; White, Nicholas J.; Su, Xin-zhuan; Char, Meng Chuor; Anderson, Jennifer M.; Amaratunga, Chanaki; Menard, Didier

2013-01-01

In 2008, dihydroartemisinin (DHA)-piperaquine (PPQ) became the first-line treatment for uncomplicated Plasmodium falciparum malaria in western Cambodia. Recent reports of increased treatment failure rates after DHA-PPQ therapy in this region suggest that parasite resistance to DHA, PPQ, or both is now adversely affecting treatment. While artemisinin (ART) resistance is established in western Cambodia, there is no evidence of PPQ resistance. To monitor for resistance to PPQ and other antimalarials, we measured drug susceptibilities for parasites collected in 2011 and 2012 from Pursat, Preah Vihear, and Ratanakiri, in western, northern, and eastern Cambodia, respectively. Using a SYBR green I fluorescence assay, we calculated the ex vivo 50% inhibitory concentrations (IC50s) of 310 parasites to six antimalarials: chloroquine (CQ), mefloquine (MQ), quinine (QN), PPQ, artesunate (ATS), and DHA. Geometric mean IC50s (GMIC50s) for all drugs (except PPQ) were significantly higher in Pursat and Preah Vihear than in Ratanakiri (P ≤ 0.001). An increased copy number of P. falciparum mdr1 (pfmdr1), an MQ resistance marker, was more prevalent in Pursat and Preah Vihear than in Ratanakiri and was associated with higher GMIC50s for MQ, QN, ATS, and DHA. An increased copy number of a chromosome 5 region (X5r), a candidate PPQ resistance marker, was detected in Pursat but was not associated with reduced susceptibility to PPQ. The ex vivo IC50 and pfmdr1 copy number are important tools in the surveillance of multidrug-resistant (MDR) parasites in Cambodia. While MDR P. falciparum is prevalent in western and northern Cambodia, there is no evidence for PPQ resistance, suggesting that DHA-PPQ treatment failures result mainly from ART resistance. PMID:23939897

Thermo-Responsive Amphiphilic Block Copolymers Stablilized Gold Nanoparticles: Synthesis and High Catalytic Properties.

PubMed

Lü, Jianhua; Yang, Yu; Gao, Junfang; Duan, Haichao; Lü, Changli

2018-06-19

A series of novel well-defined 8-hydroxyquinoline (HQ)-containing thermo-responsive amphiphilic diblock copolymers poly(styrene-co-5-(2-methacryloylethyloxy- methyl)-8-quinolinol)-b-poly(N-isopropylacrylamide) P(St-co-MQ)-b-PNIPAm (P1,2), P(NIPAm- co-MQ)-b-PSt (P3,4) and triblock copolymer poly(N-isopropylacrylamide)-b-poly(methyl- methacrylate-co-5-(2-methacryloylethyloxymethyl)-8-quinolinol)-b-polystyrene PNIPAm-b- P(MMA-co-MQ)-b-PSt (P5) were prepared by reversible addition fragmentation chain transfer (RAFT) polymerization, and their self-assembly behaviors were studied. The block copolymers P1-P5 stabilized gold nanoparticles (Au@P1-Au@P5) with small size and narrow distribution were obtained through in situ reduction of gold precursors in aqueous solution of polymer micelles with HQ as the coordination groups. The resulting Au@P nanohybrids possessed excellent catalytic activities for the reduction of nitrophenols using NaBH4. The size, morphology and surface chemistry of Au NPs could be controlled by adjusting the structure of block polymers with HQ in different block positions, which plays an important role in the catalytic properties. It was found that longer chain length of hydrophilic or hydrophobic segments of block copolymers were beneficial to elevate the catalytic activity of Au NPs for the reduction of nitrophenols, and the spherical nanoparticles (Au@P5) stabilized with triblock copolymer exhibit higher catalytic performance. Surprisingly, the gold nanowires (Au@P4) produced with P4 have a highest catalytic activity due to large abundance of grain boundaries. Excellent thermo-responsive behaviors for catalytic reaction make the as-prepared Au@P hybrids become an environmentally responsive nano-catalytic materials.

[Second neoplasm after treatment of localized prostate cancer].

PubMed

Arias, E; Astudillo, P; Manterola, C

2012-01-01

Prostate cancer (PC) treatment in early stages is radical prostatectomy (RP) or external radiotherapy (ER). There is some uncertainty regarding the development of new ER induced malignant tumors or second primary tumor (SPT), a fact influencing the choice of therapy. The purpose of this study is to determine the best therapeutic alternative for localized PC, in regards to incidence and time of development of. A systematic review of the literature is proposed by means of evaluation of studies conducted with localized PC and treated with RP or ER, published between 1990 and 2010. The Mega searchers used were Cochrane Library and Trip Database, and the data bases used were MEDLINE, OVID, Science Direct, SciELO and LiLACS, using MeSH terms and free words. The studies selected were analyzed using the MINCIR score of methodological quality (MQ) to compare articles with different design. The variables were considered to be number of patients treated, localization of lesions, global incidence of STP and MQ of the studies. Averages, medians and weighted averages (WA) were calculated. The study groups were compared using the 95% confidence intervals of the medians. Eleven articles fulfilled the screening criteria (retrospective cohorts and case series); providing 13 series for the study. The average of MQ was 14.7 points (13 and 16 points). The most frequent localizations of STP were bladder, rectum and long. The WA of the global incidence of STP for the series was 3.6% (4.1% for ER and 2.2% RP) CONCLUSION: The information existing did not make it possible to demonstrated an association between the appearance of STP and therapies for localized PC, it even though there was a superior tendency in irradiated patients. Copyright © 2011 AEU. Published by Elsevier Espana. All rights reserved.

The study of azaarene behavior over atmosphere of subtropical city(Keelung)

NASA Astrophysics Data System (ADS)

Liu, Chih Yun

2017-04-01

In this study, we collected the Total Suspended Particulates (TSP) from July 2014 to February 2016 in the subtropical city (Keelung), and researched azaarene behavior over atmosphere. Polycyclic Aromatic Compounds (PAHs) are ubiquitous pollutants in the environment; they have known carcinogens and/or mutagens, mainly produce from incomplete combustion. Azaarenes are polycyclic aromatic hydrocarbon derivative compounds in which a carbon atom in one of the aromatic rings is substituted by a nitrogen atom. Organism exposure to azaarenes occurs through inhalation of polluted air and by ingestion of food and/or water containing combustion products and accumulate in the body. Total azaarene concentration (16 individual compound concentration of the aggregate) is between 0.92 to 3.76 μg/m3, results showed that the concentration of azaarenes have significant seasonal variation, they have higher concentration in the cold month. In molecular weight, the highest proportion is the molecular weight equal to 143(ΣMQ) and then the molecular weight equal to 179(BAP), ΣMQ would rise from 30% 40% to 40% 50% during the cold month and warm months. Compared to ring number, 2-rings are biggest part, the smallest is 4-rings, its ratio has slight variation, but primary species is 2-rings. Emissions from transportation, local housing heating, factories burning fossil fuels and dust from Mainland south air mass are pollutant, their sources and climate conditions can affect concentration and composition of compound. There are highly significant correlation between 3-rings and 4-rings, which suggests that there are similar source strengths and transport mechanisms for these compounds. Correlation between concentration of azaarenes and ambient temperature is negative moderation, with concentration of atmospheric suspended particles is positive moderate correlation. Finally, we establish the relationship between the three parameters to predict concentration of azaarenes over atmosphere of subtropical regions. Key words: azaarenes, atmospheric suspended particles, subtropical city, multiple regression analysis.

Multi-dimensional photonic states from a quantum dot

NASA Astrophysics Data System (ADS)

Lee, J. P.; Bennett, A. J.; Stevenson, R. M.; Ellis, D. J. P.; Farrer, I.; Ritchie, D. A.; Shields, A. J.

2018-04-01

Quantum states superposed across multiple particles or degrees of freedom offer an advantage in the development of quantum technologies. Creating these states deterministically and with high efficiency is an ongoing challenge. A promising approach is the repeated excitation of multi-level quantum emitters, which have been shown to naturally generate light with quantum statistics. Here we describe how to create one class of higher dimensional quantum state, a so called W-state, which is superposed across multiple time bins. We do this by repeated Raman scattering of photons from a charged quantum dot in a pillar microcavity. We show this method can be scaled to larger dimensions with no reduction in coherence or single-photon character. We explain how to extend this work to enable the deterministic creation of arbitrary time-bin encoded qudits.

USAF Posture Statement 2013

DTIC Science & Technology

2013-04-12

request maintains investments in the DCGS, the MQ-1 Predator, the RC-135 Rivet Joint, the RQ-4 Global Hawk Block 40, and U-2 programs, and makes internal... electromagnetic jamming. Our potential adversaries are also making advances by electronically linking their own combat capabilities, creating new military

A Theoretical Reassessment of Microbial Maintenance and Implications for Microbial Ecology Modeling

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

Wang, Gangsheng; Post, Wilfred M

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a critical reassessment. We provided a rigorous proof that the true growth yield coefficient (YG) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert ( max,H) is higher than those in the other twomore » models ( max,P and max,C), and the difference is the physiological maintenance factor (mq = a); and (3) the overall maintenance coefficient (mT) is more sensitive to mq than to the specific growth rate ( G) and YG. Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models.« less

Molecular complexes of L-phenylalanine with substituted 1,4-benzoquinones in aqueous medium: Spectral and theoretical investigations

NASA Astrophysics Data System (ADS)

Ganesh, K.; El-Mossalamy, E. H.; Satheshkumar, A.; Balraj, C.; Elango, K. P.

2013-12-01

Various spectral techniques such as UV-Vis, FT-IR, and fluorescence have been employed to investigate the charge transfer interaction of L-phenylalanine (LPA) with substituted 1,4-benzoquinones (MQ1-4). Kinetic and thermodynamic properties of the complexes were determined in aqueous medium at physiological condition (pH = 7). The interaction of MQ1-4 with L-phenylalanine (LPA) was found to proceed through the formation of donor-acceptor complex, yielding a radical anion. The stoichiometry of the complexes was determined by Jobs continuous variation method and was found to be 1:1 in all the cases. Fluorescence quenching studies showed that the interaction between the donor and the acceptors is spontaneous. The results indicated that the progressive replacement of chlorine atom (-I effect) by methoxy group (+M effect) in the quinone decreased the electron acceptor property of the quinone. The order of the experimentally measured association constant of these complexes was well supported by DFT/B3LYP calculations.

Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

DOE PAGES

Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

2015-09-08

In carrier multiplication, the absorption of a single photon results in two or more electron–hole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. We report ultra-fast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects ofmore » electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices.« less

Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

PubMed Central

Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

2015-01-01

In carrier multiplication, the absorption of a single photon results in two or more electron–hole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. Here we report ultrafast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects of electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices. PMID:26345390

Single-shot secure quantum network coding on butterfly network with free public communication

NASA Astrophysics Data System (ADS)

Owari, Masaki; Kato, Go; Hayashi, Masahito

2018-01-01

Quantum network coding on the butterfly network has been studied as a typical example of quantum multiple cast network. We propose a secure quantum network code for the butterfly network with free public classical communication in the multiple unicast setting under restricted eavesdropper’s power. This protocol certainly transmits quantum states when there is no attack. We also show the secrecy with shared randomness as additional resource when the eavesdropper wiretaps one of the channels in the butterfly network and also derives the information sending through public classical communication. Our protocol does not require verification process, which ensures single-shot security.

An elementary quantum network using robust nuclear spin qubits in diamond

NASA Astrophysics Data System (ADS)

Kalb, Norbert; Reiserer, Andreas; Humphreys, Peter; Blok, Machiel; van Bemmelen, Koen; Twitchen, Daniel; Markham, Matthew; Taminiau, Tim; Hanson, Ronald

Quantum registers containing multiple robust qubits can form the nodes of future quantum networks for computation and communication. Information storage within such nodes must be resilient to any type of local operation. Here we demonstrate multiple robust memories by employing five nuclear spins adjacent to a nitrogen-vacancy defect centre in diamond. We characterize the storage of quantum superpositions and their resilience to entangling attempts with the electron spin of the defect centre. The storage fidelity is found to be limited by the probabilistic electron spin reset after failed entangling attempts. Control over multiple memories is then utilized to encode states in decoherence protected subspaces with increased robustness. Furthermore we demonstrate memory control in two optically linked network nodes and characterize the storage capabilities of both memories in terms of the process fidelity with the identity. These results pave the way towards multi-qubit quantum algorithms in a remote network setting.

76 FR 11308 - Notification of Pilot-in-Command; Notice of Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-01

...://spreadsheets.google.com/viewform?formkey=dExRVGF5WmtOSzZuZWxBSTdBQ2VCR1E6MQ . Specific information will be... Dangerous Goods by Air (ICAO TI). The Department of Transportation has a history and statutory mandate to...

Intelligence and Neuropsychological Aptitude Testing of U.S. Air Force MQ-1 Predator Pilot Training Candidates

DTIC Science & Technology

2012-11-01

of cognitive difficulties (e.g., memory, attention, reasoning, information processing) stemming from a head injury, medical illness (e.g., bacterial ... meningitis ), developmental disorder (e.g., attention deficit and hyperactivity, learning disorder), or emotional problems (e.g., depression, anxiety

Remote Entanglement by Coherent Multiplication of Concurrent Quantum Signals

NASA Astrophysics Data System (ADS)

Roy, Ananda; Jiang, Liang; Stone, A. Douglas; Devoret, Michel

2015-10-01

Concurrent remote entanglement of distant, noninteracting quantum entities is a crucial function for quantum information processing. In contrast with the existing protocols which employ the addition of signals to generate entanglement between two remote qubits, the continuous variable protocol we present is based on the multiplication of signals. This protocol can be straightforwardly implemented by a novel Josephson junction mixing circuit. Our scheme would be able to generate provable entanglement even in the presence of practical imperfections: finite quantum efficiency of detectors and undesired photon loss in current state-of-the-art devices.

Optically induced excitonic electroabsorption in a periodically delta-doped InGaAs/GaAs multiple quantum well structure

NASA Technical Reports Server (NTRS)

Larsson, A.; Maserjian, J.

1991-01-01

Large optically induced Stark shifts have been observed in a periodically delta-doped InGaAs/GaAs multiple quantum well structure. With an excitation intensity of 10 mW/sq cm, an absolute quantum well absorption change of 7000/cm was measured with a corresponding differential absorption change as high as 80 percent. The associated maximum change in the quantum well refractive index is 0.04. This material is promising for device development for all-optical computing and signal processing.

Gametocyte carriage in uncomplicated Plasmodium falciparum malaria following treatment with artemisinin combination therapy: a systematic review and meta-analysis of individual patient data.

PubMed

2016-05-24

Gametocytes are responsible for transmission of malaria from human to mosquito. Artemisinin combination therapy (ACT) reduces post-treatment gametocyte carriage, dependent upon host, parasite and pharmacodynamic factors. The gametocytocidal properties of antimalarial drugs are important for malaria elimination efforts. An individual patient clinical data meta-analysis was undertaken to identify the determinants of gametocyte carriage and the comparative effects of four ACTs: artemether-lumefantrine (AL), artesunate/amodiaquine (AS-AQ), artesunate/mefloquine (AS-MQ), and dihydroartemisinin-piperaquine (DP). Factors associated with gametocytaemia prior to, and following, ACT treatment were identified in multivariable logistic or Cox regression analysis with random effects. All relevant studies were identified through a systematic review of PubMed. Risk of bias was evaluated based on study design, methodology, and missing data. The systematic review identified 169 published and 9 unpublished studies, 126 of which were shared with the WorldWide Antimalarial Resistance Network (WWARN) and 121 trials including 48,840 patients were included in the analysis. Prevalence of gametocytaemia by microscopy at enrolment was 12.1 % (5887/48,589), and increased with decreasing age, decreasing asexual parasite density and decreasing haemoglobin concentration, and was higher in patients without fever at presentation. After ACT treatment, gametocytaemia appeared in 1.9 % (95 % CI, 1.7-2.1) of patients. The appearance of gametocytaemia was lowest after AS-MQ and AL and significantly higher after DP (adjusted hazard ratio (AHR), 2.03; 95 % CI, 1.24-3.12; P = 0.005 compared to AL) and AS-AQ fixed dose combination (FDC) (AHR, 4.01; 95 % CI, 2.40-6.72; P < 0.001 compared to AL). Among individuals who had gametocytaemia before treatment, gametocytaemia clearance was significantly faster with AS-MQ (AHR, 1.26; 95 % CI, 1.00-1.60; P = 0.054) and slower with DP (AHR, 0.74; 95 % CI, 0.63-0.88; P = 0.001) compared to AL. Both recrudescent (adjusted odds ratio (AOR), 9.05; 95 % CI, 3.74-21.90; P < 0.001) and new (AOR, 3.03; 95 % CI, 1.66-5.54; P < 0.001) infections with asexual-stage parasites were strongly associated with development of gametocytaemia after day 7. AS-MQ and AL are more effective than DP and AS-AQ FDC in preventing gametocytaemia shortly after treatment, suggesting that the non-artemisinin partner drug or the timing of artemisinin dosing are important determinants of post-treatment gametocyte dynamics.

Competency-based teacher training: A systematic revision of a proven programme in medical didactics.

PubMed

Griewatz, Jan; Simon, Melanie; Lammerding-Koeppel, Maria

2017-01-01

Objectives: Competency-based medical education (CBME) requires factual knowledge to be practically applied together with skills and attitudes. With the National Competence-Based Learning Objectives for Undergraduate Medical Education (NKLM) representing a strong official demand for competence-orientation, it is generally important to explicitly outline its characteristics and review its realisation in teacher trainings. Further requirements are given by the core competencies for medical teachers (KLM). As an example the MQ programme ("Medizindidaktische Qualifikation") in Baden-Wuerttemberg, a long established and well-accepted training, has been critically revised on this basis, concerning its suitability for the demands of CBME, its needs for adjustment and the efforts to be undertaken for its implementation. Methods: In a systematic quality management process the MQ curriculum and its organisational framing were analysed and further developed in a step-wise comprehensive approach, using the six-step cycle by Kern. The procedures included a thorough needs assessment (e.g. literature research, programme mapping), strategic decisions on structure and content, piloting and evaluation. During the process essential elements of project and change management were considered. Results: The experiences of the MQ example revealed helpful information for key factors to be considered in the pending change process any training provider will be confronted with. Guiding questions were developed related to the process phases. Our analyses showed persistent key points of proven value as stable foundation for change, as well as components needing special consideration to foster competence-oriented aims and transfer into practice: reflection, feedback, application-oriented methods and transparent competence development. These aspects have to be consciously perceived and experienced by participants. Taking this into account, we re-designed the course evidence-based. Besides visualising competencies and their progress, the occasions for reflection and feedback as well as the number of typical, practice-oriented tasks were extended to facilitate self-directed learning, critical self-reflection and individualised solutions. It is shown at what point, in what form and with which purpose these aspects were integrated in the MQ programme. Piloting showed good acceptance by participants, trainers. Preliminary assessment of the outcome is promising. Conclusion: Respecting the high workload, most likely medical teachers will not put CBME concepts into practice without impulses and support. Therefore, in didactical trainings, medical teachers should practice in a competency-based teaching setting and reflect themselves in different professional roles to be able to transfer the experiences to their own educational approach. Trainers and training can serve as models for CBME realisation.

Competency-based teacher training: A systematic revision of a proven programme in medical didactics

PubMed Central

Griewatz, Jan; Simon, Melanie; Lammerding-Koeppel, Maria

2017-01-01

Objectives: Competency-based medical education (CBME) requires factual knowledge to be practically applied together with skills and attitudes. With the National Competence-Based Learning Objectives for Undergraduate Medical Education (NKLM) representing a strong official demand for competence-orientation, it is generally important to explicitly outline its characteristics and review its realisation in teacher trainings. Further requirements are given by the core competencies for medical teachers (KLM). As an example the MQ programme (“Medizindidaktische Qualifikation”) in Baden-Wuerttemberg, a long established and well-accepted training, has been critically revised on this basis, concerning its suitability for the demands of CBME, its needs for adjustment and the efforts to be undertaken for its implementation. Methods: In a systematic quality management process the MQ curriculum and its organisational framing were analysed and further developed in a step-wise comprehensive approach, using the six-step cycle by Kern. The procedures included a thorough needs assessment (e.g. literature research, programme mapping), strategic decisions on structure and content, piloting and evaluation. During the process essential elements of project and change management were considered. Results: The experiences of the MQ example revealed helpful information for key factors to be considered in the pending change process any training provider will be confronted with. Guiding questions were developed related to the process phases. Our analyses showed persistent key points of proven value as stable foundation for change, as well as components needing special consideration to foster competence-oriented aims and transfer into practice: reflection, feedback, application-oriented methods and transparent competence development. These aspects have to be consciously perceived and experienced by participants. Taking this into account, we re-designed the course evidence-based. Besides visualising competencies and their progress, the occasions for reflection and feedback as well as the number of typical, practice-oriented tasks were extended to facilitate self-directed learning, critical self-reflection and individualised solutions. It is shown at what point, in what form and with which purpose these aspects were integrated in the MQ programme. Piloting showed good acceptance by participants, trainers. Preliminary assessment of the outcome is promising. Conclusion: Respecting the high workload, most likely medical teachers will not put CBME concepts into practice without impulses and support. Therefore, in didactical trainings, medical teachers should practice in a competency-based teaching setting and reflect themselves in different professional roles to be able to transfer the experiences to their own educational approach. Trainers and training can serve as models for CBME realisation. PMID:29085888

A comparison of the optical properties of InGaN/GaN multiple quantum well structures grown with and without Si-doped InGaN prelayers

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

Davies, M. J., E-mail: Matthew.Davies-2@Manchester.ac.uk; Hammersley, S.; Dawson, P.

In this paper, we report on a detailed spectroscopic study of the optical properties of InGaN/GaN multiple quantum well structures, both with and without a Si-doped InGaN prelayer. In photoluminescence and photoluminescence excitation spectroscopy, a 2nd emission band, occurring at a higher energy, was identified in the spectrum of the multiple quantum well structure containing the InGaN prelayer, originating from the first quantum well in the stack. Band structure calculations revealed that a reduction in the resultant electric field occurred in the quantum well immediately adjacent to the InGaN prelayer, therefore leading to a reduction in the strength of themore » quantum confined Stark effect in this quantum well. The partial suppression of the quantum confined Stark effect in this quantum well led to a modified (higher) emission energy and increased radiative recombination rate. Therefore, we ascribed the origin of the high energy emission band to recombination from the 1st quantum well in the structure. Study of the temperature dependent recombination dynamics of both samples showed that the decay time measured across the spectrum was strongly influenced by the 1st quantum well in the stack (in the sample containing the prelayer) leading to a shorter average room temperature lifetime in this sample. The room temperature internal quantum efficiency of the prelayer containing sample was found to be higher than the reference sample (36% compared to 25%) which was thus attributed to the faster radiative recombination rate of the 1st quantum well providing a recombination pathway that is more competitive with non-radiative recombination processes.« less

Scanning gate imaging of two coupled quantum dots in single-walled carbon nanotubes.

PubMed

Zhou, Xin; Hedberg, James; Miyahara, Yoichi; Grutter, Peter; Ishibashi, Koji

2014-12-12

Two coupled single wall carbon nanotube quantum dots in a multiple quantum dot system were characterized by using a low temperature scanning gate microscopy (SGM) technique, at a temperature of 170 mK. The locations of single wall carbon nanotube quantum dots were identified by taking the conductance images of a single wall carbon nanotube contacted by two metallic electrodes. The single electron transport through single wall carbon nanotube multiple quantum dots has been observed by varying either the position or voltage bias of a conductive atomic force microscopy tip. Clear hexagonal patterns were observed in the region of the conductance images where only two sets of overlapping conductance rings are visible. The values of coupling capacitance over the total capacitance of the two dots, C(m)/C(1(2)) have been extracted to be 0.21 ∼ 0.27 and 0.23 ∼ 0.28, respectively. In addition, the interdot coupling (conductance peak splitting) has also been confirmed in both conductance image measurement and current-voltage curves. The results show that a SGM technique enables spectroscopic investigation of coupled quantum dots even in the presence of unexpected multiple quantum dots.

Enhancement of optical Kerr effect in quantum-cascade lasers with multiple resonance levels.

PubMed

Bai, Jing; Citrin, D S

2008-08-18

In this paper, we investigated the optical Kerr lensing effect in quantum-cascade lasers with multiple resonance levels. The Kerr refractive index n2 is obtained through the third-order susceptibility at the fundamental frequency chi(3)( omega; omega, omega,-omega). Resonant two-photon processes are found to have almost equal contributions to chi(3)( omega; omega, omega,-omega) as the single-photon processes, which result in the predicted enhancement of the positive nonlinear (Kerr) refractive index, and thus may enhance mode-locking of quantum-cascade lasers. Moreover, we also demonstrate an isospectral optimization strategy for further improving n2 through the band-structure design, in order to boost the multimode performance of quantum-cascade lasers. Simulation results show that the optimized stepwise multiple-quantum-well structure has n2 approximately 10-8 cm2/W, a twofold enhancement over the original flat quantum-well structure. This leads to a refractive-index change (delta)n of about 0.01, which is at the upper bound of those reported for typical Kerr medium. This stronger Kerr refractive index may be important for quantum-cascade lasers ultimately to demonstrate self-mode-locking.

Simultaneous entanglement swapping of multiple orbital angular momentum states of light.

PubMed

Zhang, Yingwen; Agnew, Megan; Roger, Thomas; Roux, Filippus S; Konrad, Thomas; Faccio, Daniele; Leach, Jonathan; Forbes, Andrew

2017-09-21

High-bit-rate long-distance quantum communication is a proposed technology for future communication networks and relies on high-dimensional quantum entanglement as a core resource. While it is known that spatial modes of light provide an avenue for high-dimensional entanglement, the ability to transport such quantum states robustly over long distances remains challenging. To overcome this, entanglement swapping may be used to generate remote quantum correlations between particles that have not interacted; this is the core ingredient of a quantum repeater, akin to repeaters in optical fibre networks. Here we demonstrate entanglement swapping of multiple orbital angular momentum states of light. Our approach does not distinguish between different anti-symmetric states, and thus entanglement swapping occurs for several thousand pairs of spatial light modes simultaneously. This work represents the first step towards a quantum network for high-dimensional entangled states and provides a test bed for fundamental tests of quantum science.Entanglement swapping in high dimensions requires large numbers of entangled photons and consequently suffers from low photon flux. Here the authors demonstrate entanglement swapping of multiple spatial modes of light simultaneously, without the need for increasing the photon numbers with dimension.

Unmanned Systems Integrated Roadmap, FY2013-2038

DTIC Science & Technology

2014-01-01

29 4.1.7 Sensor Air Drop...Force MQ-1/9 Pilot & Sensor Operator Training Flow ...................................... 106 Figure 39. UAS Training Objectives...the Nation’s 10 years of war wind down, DoD inventories and funding of UGS are expected to decrease in 2014, followed by a gradual upward trend in 2016

Harmonic Quantum Coherence of Multiple Excitons in PbS/CdS Core-Shell Nanocrystals

NASA Astrophysics Data System (ADS)

Tahara, Hirokazu; Sakamoto, Masanori; Teranishi, Toshiharu; Kanemitsu, Yoshihiko

2017-12-01

The generation and recombination dynamics of multiple excitons in nanocrystals (NCs) have attracted much attention from the viewpoints of fundamental physics and device applications. However, the quantum coherence of multiple exciton states in NCs still remains unclear due to a lack of experimental support. Here, we report the first observation of harmonic dipole oscillations in PbS/CdS core-shell NCs using a phase-locked interference detection method for transient absorption. From the ultrafast coherent dynamics and excitation-photon-fluence dependence of the oscillations, we found that multiple excitons cause the harmonic dipole oscillations with ω , 2 ω , and 3 ω oscillations, even though the excitation pulse energy is set to the exciton resonance frequency, ω . This observation is closely related to the quantum coherence of multiple exciton states in NCs, providing important insights into multiple exciton generation mechanisms.

Nonadiabatic quantum path analysis of high-order harmonic generation: Role of the carrier-envelope phase on short and long paths

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

Sansone, G.; Stagira, S.; Nisoli, M.

2004-07-01

High-order harmonic generation process in the few- and multiple-optical-cycle regime is theoretically investigated, using the saddle-point method generalized to account for nonadiabatic effects. The influence of the carrier-envelope phase of the driving pulses on the various electron quantum paths is analyzed. We demonstrate that the short and long quantum paths are influenced in different ways by the carrier-envelope phase. In particular, we show that clear phase effects are visible on the long quantum paths even in the multiple-optical-cycle regime, while the short quantum paths are significantly influenced by the carrier-envelope phase only in the few-optical-cycle regime.

The set of triple-resonance sequences with a multiple quantum coherence evolution period

NASA Astrophysics Data System (ADS)

Koźmiński, Wiktor; Zhukov, Igor

2004-12-01

The new pulse sequence building block that relies on evolution of heteronuclear multiple quantum coherences is proposed. The particular chemical shifts are obtained in multiple quadrature, using linear combinations of frequencies taken from spectra measured at different quantum levels. The pulse sequences designed in this way consist of small number of RF-pulses, are as short as possible, and could be applied for determination of coupling constants. The examples presented involve 2D correlations H NCO, H NCA, H N(CO) CA, and H(N) COCA via heteronuclear zero and double coherences, as well as 2D H NCOCA technique with simultaneous evolution of triple and three distinct single quantum coherences. Applications of the new sequences are presented for 13C, 15N-labeled ubiquitin.

Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: second-order quadrupolar and resonance offset effects.

PubMed

Ashbrook, Sharon E; Wimperis, Stephen

2009-11-21

Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of small resonance offset and second-order quadrupolar interactions has been investigated using both exact and approximate theoretical and experimental nuclear magnetic resonance (NMR) approaches. In the presence of second-order quadrupolar interactions, we show that the initial rapid dephasing that arises from the noncommutation of the state prepared by the first pulse and the spin-locking Hamiltonian gives rise to tensor components of the spin density matrix that are antisymmetric with respect to inversion, in addition to those symmetric with respect to inversion that are found when only a first-order quadrupolar interaction is considered. We also find that spin-locking of multiple-quantum coherence in a static solid is much more sensitive to resonance offset than that of single-quantum coherence and show that good spin-locking of multiple-quantum coherence can still be achieved if the resonance offset matches the second-order shift of the multiple-quantum coherence in the appropriate reference frame. Under magic angle spinning (MAS) conditions, and in the "adiabatic" limit, we demonstrate that rotor-driven interconversion of central-transition single- and three-quantum coherences for a spin I=3/2 nucleus can be best achieved by performing the spin-locking on resonance with the three-quantum coherence in the three-quantum frame. Finally, in the "sudden" MAS limit, we show that spin I=3/2 spin-locking behavior is generally similar to that found in static solids, except when the central-transition nutation rate matches a multiple of the MAS rate and a variety of rotary resonance phenomena are observed depending on the internal spin interactions present. This investigation should aid in the application of spin-locking techniques to multiple-quantum NMR of quadrupolar nuclei and of cross-polarization and homonuclear dipolar recoupling experiments to quadrupolar nuclei such as (7)Li, (11)B, (17)O, (23)Na, and (27)Al.

Photovoltaic driven multiple quantum well optical modulator

NASA Technical Reports Server (NTRS)

Maserjian, Joseph (Inventor)

1990-01-01

Multiple quantum well (MQW) structures (12) are utilized to provide real-time, reliable, high-performance, optically-addressed spatial-light modulators (SLM) (10). The optically-addressed SLM comprises a vertical stack of quantum well layers (12a) within the penetration depth of an optical write signal 18, a plurality of space charge barriers (12b) having predetermined tunneling times by control of doping and thickness. The material comprising the quantum well layers has a lower bandgap than that of the space charge barrier layers. The write signal modulates a read signal (20). The modulation sensitivity of the device is high and no external voltage source is required. In a preferred embodiment, the SLM having interleaved doped semiconductor layers for driving the MQW photovoltaically is characterized by the use of a shift analogous to the Moss-Burnstein shift caused by the filling of two-dimensional states in the multiple quantum wells, thus allowing high modulation sensitivity in very narrow wells. Arrays (30) may be formed with a plurality of the modulators.

Evolution of multiple quantum coherences with scaled dipolar Hamiltonian

NASA Astrophysics Data System (ADS)

Sánchez, Claudia M.; Buljubasich, Lisandro; Pastawski, Horacio M.; Chattah, Ana K.

2017-08-01

In this article, we introduce a pulse sequence which allows the monitoring of multiple quantum coherences distribution of correlated spin states developed with scaled dipolar Hamiltonian. The pulse sequence is a modification of our previous Proportionally Refocused Loschmidt echo (PRL echo) with phase increment, in order to verify the accuracy of the weighted coherent quantum dynamics. The experiments were carried out with different scaling factors to analyze the evolution of the total magnetization, the time dependence of the multiple quantum coherence orders, and the development of correlated spins clusters. In all cases, a strong dependence between the evolution rate and the weighting factor is observed. Remarkably, all the curves appeared overlapped in a single trend when plotted against the self-time, a new time scale that includes the scaling factor into the evolution time. In other words, the spin system displayed always the same quantum evolution, slowed down as the scaling factor decreases, confirming the high performance of the new pulse sequence.

Self-assembly of vertically aligned quantum ring-dot structure by Multiple Droplet Epitaxy

NASA Astrophysics Data System (ADS)

Elborg, Martin; Noda, Takeshi; Mano, Takaaki; Kuroda, Takashi; Yao, Yuanzhao; Sakuma, Yoshiki; Sakoda, Kazuaki

2017-11-01

We successfully grow vertically aligned quantum ring-dot structures by Multiple Droplet Epitaxy technique. The growth is achieved by depositing GaAs quantum rings in a first droplet epitaxy process which are subsequently covered by a thin AlGaAs barrier. In a second droplet epitaxy process, Ga droplets preferentially position in the center indentation of the ring as well as attached to the edge of the ring in [ 1 1 bar 0 ] direction. By designing the ring geometry, full selectivity for the center position of the ring is achieved where we crystallize the droplets into quantum dots. The geometry of the ring and dot as well as barrier layer can be controlled in separate growth steps. This technique offers great potential for creating complex quantum molecules for novel quantum information technologies.

Message Brokering Evaluation for Live Spacecraft Telemetry Monitoring, Recorded Playback, and Analysis

NASA Technical Reports Server (NTRS)

Lee, Daren; Pomerantz, Marc

2015-01-01

Live monitoring and post-flight analysis of telemetry data play a vital role in the development, diagnosis, and deployment of components of a space flight mission. Requirements for such a system include low end-to-end latency between data producers and visualizers, preserved ordering of messages, data stream archiving with random access playback, and real-time creation of derived data streams. We evaluate the RabbitMQ and Kafka message brokering systems, on how well they can enable a real-time, scalable, and robust telemetry framework that delivers telemetry data to multiple clients across heterogeneous platforms and flight projects. In our experiments using an actively developed robotic arm testbed, Kafka yielded a much higher message throughput rate and a consistent publishing rate across the number of topics and consumers. Consumer message rates were consistent across the number of topics but can exhibit bursty behavior with an increase in the contention for a single topic partition with increasing number of consumers.

Strong quantum-confined Stark effect in a lattice-matched GeSiSn/GeSn multi-quantum-well structure

NASA Astrophysics Data System (ADS)

Peng, Ruizhi; Chunfuzhang; Han, Genquan; Hao, Yue

2017-06-01

This paper presents modeling and simulation of a multiple quantum well structure formed with Ge0.95Sn0.05 quantum wells separated by Ge0.51Si0.35Sn0.14 barriers for the applications. These alloy compositions are chosen to satisfy two conditions simultaneously: type-I band alignment between Ge0.95Sn0.05/Ge0.51Si0.35Sn0.14 and a lattice match between wells and barriers. This lattice match ensures that the strain-free structure can be grown upon a relaxed Ge0.51Si0.35Sn0.14 buffer on a silicon substrate - a CMOS compatible process. A electro-absorption modulator with the Ge0.95Sn0.05/Ge0.51Si0.35Sn0.14 multiple quantum well structure based on quantum-confined Stark effect(QCSE) is demonstrated in theory. The energy band diagrams of the GeSiSn/GeSn multi-quantum-well structure at 0 and 0.5V bias are calculated, respectively. And the corresponding absorption coefficients as a function of cut-off energy for this multiple quantum well structure at 0 and 0.5Vbias are also obtained, respectively. The reduction of cut-off energy is observed with the applying of the external electric field, indicating a strong QCSE in the structure.

Controlled quantum perfect teleportation of multiple arbitrary multi-qubit states

NASA Astrophysics Data System (ADS)

Shi, Runhua; Huang, Liusheng; Yang, Wei; Zhong, Hong

2011-12-01

We present an efficient controlled quantum perfect teleportation scheme. In our scheme, multiple senders can teleport multiple arbitrary unknown multi-qubit states to a single receiver via a previously shared entanglement state with the help of one or more controllers. Furthermore, our scheme has a very good performance in the measurement and operation complexity, since it only needs to perform Bell state and single-particle measurements and to apply Controlled-Not gate and other single-particle unitary operations. In addition, compared with traditional schemes, our scheme needs less qubits as the quantum resources and exchanges less classical information, and thus obtains higher communication efficiency.

Joint measurement of multiple noncommuting parameters

NASA Astrophysics Data System (ADS)

Li, Jiamin; Liu, Yuhong; Cui, Liang; Huo, Nan; Assad, Syed M.; Li, Xiaoying; Ou, Z. Y.

2018-05-01

Although quantum metrology allows us to make precision measurements beyond the standard quantum limit, it mostly works on the measurement of only one observable due to the Heisenberg uncertainty relation on the measurement precision of noncommuting observables for one system. In this paper, we study the schemes of joint measurement of multiple observables which do not commute with each other using the quantum entanglement between two systems. We focus on analyzing the performance of a SU(1,1) nonlinear interferometer on fulfilling the task of joint measurement. The results show that the information encoded in multiple noncommuting observables on an optical field can be simultaneously measured with a signal-to-noise ratio higher than the standard quantum limit, and the ultimate limit of each observable is still the Heisenberg limit. Moreover, we find a resource conservation rule for the joint measurement.

Band-edge absorption coefficients from photoluminescence in semiconductor multiple quantum wells

NASA Technical Reports Server (NTRS)

Kost, Alan; Zou, Yao; Dapkus, P. D.; Garmire, Elsa; Lee, H. C.

1989-01-01

A novel approach to determining absorption coefficients in thin films using luminescence is described. The technique avoids many of the difficulties typically encountered in measurements of thin samples, Fabry-Perot effects, for example, and can be applied to a variety of materials. The absorption edge for GaAs/AlGaAs multiple quantum well structures, with quantum well widths ranging from 54 to 193 A is examined. Urbach (1953) parameters and excitonic linewidths are tabulated.

Quantum Dots for Molecular Pathology

PubMed Central

True, Lawrence D.; Gao, Xiaohu

2007-01-01

Assessing malignant tumors for expression of multiple biomarkers provides data that are critical for patient management. Quantum dot-conjugated probes to specific biomarkers are powerful tools that can be applied in a multiplex manner to single tissue sections of biopsies to measure expression levels of multiple biomarkers. PMID:17251330

Analysis of KC-46 Live-Fire Risk Mitigation Program Testing

DTIC Science & Technology

2012-03-01

the use of real hardware such as electrohydraulic actuators , electrical units, and converter regulators (Andrus, 2010). The only feasible method for...worked with the MQ-9 as a test engineer and analyst for the programs IOT &E, RQ-4 as lead engineer and program lead for the block 3 and the block 4

A theoretical reassessment of microbial maintenance and implications for microbial ecology modeling.

PubMed

Wang, Gangsheng; Post, Wilfred M

2012-09-01

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a theoretical reassessment. We provided a rigorous proof that the true growth yield coefficient (Y(G)) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert (μ(max,H)) is higher than those in the other two models (μ(max,P) and μ(max,C)), and the difference is the physiological maintenance factor (m(q) = a); and (3) the overall maintenance coefficient (m(T)) is more sensitive to m(q) than to the specific growth rate (μ(G)) and Y(G). Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models. © This article is a US government work and is in the public domain in the USA.

Heavy quarkonium hybrids: Spectrum, decay, and mixing

NASA Astrophysics Data System (ADS)

Oncala, Ruben; Soto, Joan

2017-07-01

We present a largely model-independent analysis of the lighter heavy quarkonium hybrids based on the strong coupling regime of potential nonrelativistic QCD. We calculate the spectrum at leading order, including the mixing of static hybrid states. We use potentials that fulfill the required short and long distance theoretical constraints and fit well the available lattice data. We argue that the decay width to the lower lying heavy quarkonia can be reliably estimated in some cases and provide results for a selected set of decays. We also consider the mixing with heavy quarkonium states. We establish the form of the mixing potential at O (1 /mQ) , mQ being the mass of the heavy quarks, and work out its short and long distance constraints. The weak coupling regime of potential nonrelativistic QCD and the effective string theory of QCD are used for that goal. We show that the mixing effects may indeed be important and produce large spin symmetry violations. Most of the isospin zero XYZ states fit well in our spectrum, either as a hybrid or standard quarkonium candidate.

Molecular complexes of l-phenylalanine with substituted 1,4-benzoquinones in aqueous medium: spectral and theoretical investigations.

PubMed

Ganesh, K; El-Mossalamy, E H; Satheshkumar, A; Balraj, C; Elango, K P

2013-12-01

Various spectral techniques such as UV-Vis, FT-IR, and fluorescence have been employed to investigate the charge transfer interaction of L-phenylalanine (LPA) with substituted 1,4-benzoquinones (MQ(1-4)). Kinetic and thermodynamic properties of the complexes were determined in aqueous medium at physiological condition (pH=7). The interaction of MQ(1-4) with L-phenylalanine (LPA) was found to proceed through the formation of donor-acceptor complex, yielding a radical anion. The stoichiometry of the complexes was determined by Jobs continuous variation method and was found to be 1:1 in all the cases. Fluorescence quenching studies showed that the interaction between the donor and the acceptors is spontaneous. The results indicated that the progressive replacement of chlorine atom (-I effect) by methoxy group (+M effect) in the quinone decreased the electron acceptor property of the quinone. The order of the experimentally measured association constant of these complexes was well supported by DFT/B3LYP calculations. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral collocation method with a flexible angular discretization scheme for radiative transfer in multi-layer graded index medium

NASA Astrophysics Data System (ADS)

Wei, Linyang; Qi, Hong; Sun, Jianping; Ren, Yatao; Ruan, Liming

2017-05-01

The spectral collocation method (SCM) is employed to solve the radiative transfer in multi-layer semitransparent medium with graded index. A new flexible angular discretization scheme is employed to discretize the solid angle domain freely to overcome the limit of the number of discrete radiative direction when adopting traditional SN discrete ordinate scheme. Three radial basis function interpolation approaches, named as multi-quadric (MQ), inverse multi-quadric (IMQ) and inverse quadratic (IQ) interpolation, are employed to couple the radiative intensity at the interface between two adjacent layers and numerical experiments show that MQ interpolation has the highest accuracy and best stability. Variable radiative transfer problems in double-layer semitransparent media with different thermophysical properties are investigated and the influence of these thermophysical properties on the radiative transfer procedure in double-layer semitransparent media is also analyzed. All the simulated results show that the present SCM with the new angular discretization scheme can predict the radiative transfer in multi-layer semitransparent medium with graded index efficiently and accurately.

Masses and ages of Delta Scuti stars in eclipsing binary systems

NASA Astrophysics Data System (ADS)

Tsvetkov, Ts. G.; Petrova, Ts. C.

1993-05-01

By using data mainly from Frolov et al. (1982) for four Delta Scuti stars in eclipsing binary systems, AB Cas, Y Cam, RS Cha, and AI Hya, their physical parameters, distances, and radial pulsation modes are determined. The evolutionary track systems of Iben (1967), Paczynski (1970), and Maeder and Meynet (1988) are interpolated in order to estimate evolutionary masses Me and ages t of these variables. Their pulsation masses MQ are estimated from the fitting formulae of Faulkner (1977) and Fitch (1981). Our estimates of evolutionary masses M(e) and pulsation masses M(Q) are close to the masses M determined by Frolov et al. from the star binarity. The only exception is AB Cas, for which there is no agreement between certain star parameters. Another, independent approach is also applied to the stars RS Cha and AI Hya: by using their photometric indices b - y and c(1) from the catalog of Lopez de Coca et al. (1990) and appropriate photometric calibrations, other sets of physical parameters, distances, modes, ages, and evolutionary and pulsation masses of both variables are obtained.

Investigation of Photoluminescence and Photocurrent in InGaAsP/InP Strained Multiple Quantum Well Heterostructures

NASA Technical Reports Server (NTRS)

Raisky, O. Y.; Wang, W. B.; Alfano, R. R.; Reynolds, C. L., Jr.; Swaminathan, V.

1997-01-01

Multiple quantum well InGaAsP/InP p-i-n laser heterostructures with different barrier thicknesses have been investigated using photoluminescence (PL) and photocurrent (PC) measurements. The observed PL spectrum and peak positions are in good agreement with those obtained from transfer matrix calculations. Comparing the measured quantum well PC with calculated carrier escape rates, the photocurrent changes are found to be governed by the temperature dependence of the electron escape time.

Low-level (submicromole) environmental 14C metrology

NASA Astrophysics Data System (ADS)

Currie, L. A.; Kessler, J. D.; Marolf, J. V.; McNichol, A. P.; Stuart, D. R.; Donoghue, J. C.; Donahue, D. J.; Burr, G. S.; Biddulph, D.

2000-10-01

Accelerator mass spectrometry (AMS) measurements of environmental 14C have been employed during the past decade at the several micromole level (tens of μg carbon), but advanced research in the atmospheric and marine sciences demands still higher (μg) sensitivity, an extreme example being the determination of 14C in elemental or "black" carbon (BC) at levels of 2-10 μg per kg of Greenland snow and ice (Currie et al., 1998). A fundamental limitation for 14C AMS is Poisson counting statistics, which sets in at about 1 μg modern-C. Using the small sample (25 μg) AMS target preparation facility at NOSAMS (Pearson et al., 1998), and the microsample combustion-dilution facility at NIST, we have demonstrated an intrinsic modern-C quantification limit ( mQ) of ca. 0.9 μg, based on a 1-parameter fit to the empirical AMS variance function. (For environmental 14C, the modern carbon quantification limit is defined as that mass ( mQ) corresponding to 10% relative standard deviation (rsd) for the fraction of modern carbon, σ( fM)/ fM.) Stringent control, required for quantitative dilution factors (DL), is achieved with the NIST on-line manometric/mass spectrometry facility that compensates also for unsuspected trace impurities from vigorous chemical processing (e.g., acid digestion). Our current combustion blank is trivial (mean: 0.16 ± 0.02 μg C, n=13) but lognormally distributed (dispersion [σ]: 0.07 ± 0.01 μg). An iterative numerical expression is introduced to assess the quantitative impacts of fossil and modern carbon blank components on mQ; and a new "clean chemistry" BC processing system is described for the minimization of such blanks. For the assay of soot carbon in Greenland snow/ice, the overall processing blank has been reduced from nearly 7 μg total carbon to less than 1 μg, and is undetectable for BC.

Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences.

PubMed

Gärttner, Martin; Hauke, Philipp; Rey, Ana Maria

2018-01-26

Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has been derived, the latter only quantifies entanglement in pure systems and is hard to access experimentally. In this work, we formally demonstrate that the multiple-quantum coherence spectra, a specific family of OTOCs well known in NMR, can be used as an entanglement witness and as a direct probe of multiparticle entanglement. Our results open a path to experimentally testing the fascinating idea that entanglement is the underlying glue that links thermodynamics, statistical mechanics, and quantum gravity.

Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences

NASA Astrophysics Data System (ADS)

Gärttner, Martin; Hauke, Philipp; Rey, Ana Maria

2018-01-01

Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has been derived, the latter only quantifies entanglement in pure systems and is hard to access experimentally. In this work, we formally demonstrate that the multiple-quantum coherence spectra, a specific family of OTOCs well known in NMR, can be used as an entanglement witness and as a direct probe of multiparticle entanglement. Our results open a path to experimentally testing the fascinating idea that entanglement is the underlying glue that links thermodynamics, statistical mechanics, and quantum gravity.

On the effect of ballistic overflow on the temperature dependence of the quantum efficiency of InGaN/GaN multiple quantum well light-emitting diodes

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

Prudaev, I. A., E-mail: funcelab@gmail.com; Kopyev, V. V.; Romanov, I. S.

The dependences of the quantum efficiency of InGaN/GaN multiple quantum well light-emitting diodes on the temperature and excitation level are studied. The experiment is performed for two luminescence excitation modes. A comparison of the results obtained during photo- and electroluminescence shows an additional (to the loss associated with Auger recombination) low-temperature loss in the high-density current region. This causes inversion of the temperature dependence of the quantum efficiency at temperatures lower than 220–300 K. Analysis shows that the loss is associated with electron leakage from the light-emitting-diode active region. The experimental data are explained using the ballistic-overflow model. The simulationmore » results are in qualitative agreement with the experimental dependences of the quantum efficiency on temperature and current density.« less

Lead Telluride Quantum Dot Solar Cells Displaying External Quantum Efficiencies Exceeding 120%

PubMed Central

2015-01-01

Multiple exciton generation (MEG) in semiconducting quantum dots is a process that produces multiple charge-carrier pairs from a single excitation. MEG is a possible route to bypass the Shockley-Queisser limit in single-junction solar cells but it remains challenging to harvest charge-carrier pairs generated by MEG in working photovoltaic devices. Initial yields of additional carrier pairs may be reduced due to ultrafast intraband relaxation processes that compete with MEG at early times. Quantum dots of materials that display reduced carrier cooling rates (e.g., PbTe) are therefore promising candidates to increase the impact of MEG in photovoltaic devices. Here we demonstrate PbTe quantum dot-based solar cells, which produce extractable charge carrier pairs with an external quantum efficiency above 120%, and we estimate an internal quantum efficiency exceeding 150%. Resolving the charge carrier kinetics on the ultrafast time scale with pump–probe transient absorption and pump–push–photocurrent measurements, we identify a delayed cooling effect above the threshold energy for MEG. PMID:26488847

The Misapplication of Probability Theory in Quantum Mechanics

NASA Astrophysics Data System (ADS)

Racicot, Ronald

2014-03-01

This article is a revision of two papers submitted to the APS in the past two and a half years. In these papers, arguments and proofs are summarized for the following: (1) The wrong conclusion by EPR that Quantum Mechanics is incomplete, perhaps requiring the addition of ``hidden variables'' for completion. Theorems that assume such ``hidden variables,'' such as Bell's theorem, are also wrong. (2) Quantum entanglement is not a realizable physical phenomenon and is based entirely on assuming a probability superposition model for quantum spin. Such a model directly violates conservation of angular momentum. (3) Simultaneous multiple-paths followed by a quantum particle traveling through space also cannot possibly exist. Besides violating Noether's theorem, the multiple-paths theory is based solely on probability calculations. Probability calculations by themselves cannot possibly represent simultaneous physically real events. None of the reviews of the submitted papers actually refuted the arguments and evidence that was presented. These analyses should therefore be carefully evaluated since the conclusions reached have such important impact in quantum mechanics and quantum information theory.

Tuning diagonal components of static linear and first nonlinear polarizabilities of doped quantum dots by Gaussian white noise

NASA Astrophysics Data System (ADS)

Ganguly, Jayanta; Ghosh, Manas

2015-07-01

We investigate the modulation of diagonal components of static linear (αxx, αyy) and first nonlinear (βxxx, βyyy) polarizabilities of quantum dots by Gaussian white noise. Quantum dot is doped with impurity represented by a Gaussian potential and repulsive in nature. The study reveals the importance of mode of application of noise (additive/multiplicative) on the polarizability components. The doped system is further exposed to a static external electric field of given intensity. As important observation we have found that the strength of additive noise becomes unable to influence the polarizability components. However, the multiplicative noise influences them conspicuously and gives rise to additional interesting features. Multiplicative noise even enhances the magnitude of the polarizability components immensely. The present investigation deems importance in view of the fact that noise seriously affects the optical properties of doped quantum dot devices.

Entropic formulation for the protein folding process: Hydrophobic stability correlates with folding rates

NASA Astrophysics Data System (ADS)

Dal Molin, J. P.; Caliri, A.

2018-01-01

Here we focus on the conformational search for the native structure when it is ruled by the hydrophobic effect and steric specificities coming from amino acids. Our main tool of investigation is a 3D lattice model provided by a ten-letter alphabet, the stereochemical model. This minimalist model was conceived for Monte Carlo (MC) simulations when one keeps in mind the kinetic behavior of protein-like chains in solution. We have three central goals here. The first one is to characterize the folding time (τ) by two distinct sampling methods, so we present two sets of 103 MC simulations for a fast protein-like sequence. The resulting sets of characteristic folding times, τ and τq were obtained by the application of the standard Metropolis algorithm (MA), as well as by an enhanced algorithm (Mq A). The finding for τq shows two things: (i) the chain-solvent hydrophobic interactions {hk } plus a set of inter-residues steric constraints {ci,j } are able to emulate the conformational search for the native structure. For each one of the 103MC performed simulations, the target is always found within a finite time window; (ii) the ratio τq / τ ≅ 1 / 10 suggests that the effect of local thermal fluctuations, encompassed by the Tsallis weight, provides to the chain an innate efficiency to escape from energetic and steric traps. We performed additional MC simulations with variations of our design rule to attest this first result, both algorithms the MA and the Mq A were applied to a restricted set of targets, a physical insight is provided. Our second finding was obtained by a set of 600 independent MC simulations, only performed with the Mq A applied to an extended set of 200 representative targets, our native structures. The results show how structural patterns should modulate τq, which cover four orders of magnitude; this finding is our second goal. The third, and last result, was obtained with a special kind of simulation performed with the purpose to explore a possible connection between the hydrophobic component of protein stability and the native structural topology. We simulated those same 200 targets again with the Mq A, only. However, this time we evaluated the relative frequency {ϕq } in which each target visits its corresponding native structure along an appropriate simulation time. Due to the presence of the hydrophobic effect in our approach we obtained a strong correlation between the stability and the folding rate (R = 0 . 85). So, as faster a sequence found its target, as larger is the hydrophobic component of its stability. The strong correlation fulfills our last goal. This final finding suggests that the hydrophobic effect could not be a general stabilizing factor for proteins.

Ultrafast carrier capture and Auger recombination in single GaN/InGaN multiple quantum well nanowires

DOE PAGES

Boubanga-Tombet, Stephane; Wright, Jeremy B.; Lu, Ping; ...

2016-11-04

Ultrafast optical microscopy is an important tool for examining fundamental phenomena in semiconductor nanowires with high temporal and spatial resolution. In this paper, we used this technique to study carrier dynamics in single GaN/InGaN core–shell nonpolar multiple quantum well nanowires. We find that intraband carrier–carrier scattering is the main channel governing carrier capture, while subsequent carrier relaxation is dominated by three-carrier Auger recombination at higher densities and bimolecular recombination at lower densities. Finally, the Auger constants in these nanowires are approximately 2 orders of magnitude lower than in planar InGaN multiple quantum wells, highlighting their potential for future light-emitting devices.

Measuring out-of-time-order correlations and multiple quantum spectra in a trapped-ion quantum magnet

NASA Astrophysics Data System (ADS)

Gärttner, Martin; Bohnet, Justin G.; Safavi-Naini, Arghavan; Wall, Michael L.; Bollinger, John J.; Rey, Ana Maria

2017-08-01

Controllable arrays of ions and ultracold atoms can simulate complex many-body phenomena and may provide insights into unsolved problems in modern science. To this end, experimentally feasible protocols for quantifying the buildup of quantum correlations and coherence are needed, as performing full state tomography does not scale favourably with the number of particles. Here we develop and experimentally demonstrate such a protocol, which uses time reversal of the many-body dynamics to measure out-of-time-order correlation functions (OTOCs) in a long-range Ising spin quantum simulator with more than 100 ions in a Penning trap. By measuring a family of OTOCs as a function of a tunable parameter we obtain fine-grained information about the state of the system encoded in the multiple quantum coherence spectrum, extract the quantum state purity, and demonstrate the buildup of up to 8-body correlations. Future applications of this protocol could enable studies of many-body localization, quantum phase transitions, and tests of the holographic duality between quantum and gravitational systems.

Classical system boundaries cannot be determined within quantum Darwinism

NASA Astrophysics Data System (ADS)

Fields, Chris

Multiple observers who interact with environmental encodings of the states of a macroscopic quantum system S as required by quantum Darwinism cannot demonstrate that they are jointly observing S without a joint a priori assumption of a classical boundary separating S from its environment E. Quantum Darwinism cannot, therefore, be regarded as providing a purely quantum-mechanical explanation of the "emergence" of classicality.

Multiple lobes in the far-field distribution of terahertz quantum-cascade lasers due to self-interference

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

Röben, B., E-mail: roeben@pdi-berlin.de; Wienold, M.; Schrottke, L.

2016-06-15

The far-field distribution of the emission intensity of terahertz (THz) quantum-cascade lasers (QCLs) frequently exhibits multiple lobes instead of a single-lobed Gaussian distribution. We show that such multiple lobes can result from self-interference related to the typically large beam divergence of THz QCLs and the presence of an inevitable cryogenic operation environment including optical windows. We develop a quantitative model to reproduce the multiple lobes. We also demonstrate how a single-lobed far-field distribution can be achieved.

Highly efficient multiple-layer CdS quantum dot sensitized III-V solar cells.

PubMed

Lin, Chien-Chung; Han, Hau-Vei; Chen, Hsin-Chu; Chen, Kuo-Ju; Tsai, Yu-Lin; Lin, Wein-Yi; Kuo, Hao-Chung; Yu, Peichen

2014-02-01

In this review, the concept of utilization of solar spectrum in order to increase the solar cell efficiency is discussed. Among the three mechanisms, down-shifting effect is investigated in detail. Organic dye, rare-earth minerals and quantum dots are three most popular down-shift materials. While the enhancement of solar cell efficiency was not clearly observed in the past, the advances in quantum dot fabrication have brought strong response out of the hybrid platform of a quantum dot solar cell. A multiple layer structure, including PDMS as the isolation layer, is proposed and demonstrated. With the help of pulse spray system, precise control can be achieved and the optimized concentration can be found.

Roles of V-shaped pits on the improvement of quantum efficiency in InGaN/GaN multiple quantum well light-emitting diodes

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

Quan, Zhijue, E-mail: quanzhijue@ncu.edu.cn; Wang, Li, E-mail: wl@ncu.edu.cn; Zheng, Changda

2014-11-14

The roles of V-shaped pits on the improvement of quantum efficiency in InGaN/GaN multiple quantum well (MQW) light-emitting diodes are investigated by numerical simulation. The simulation results show that V-shaped pits cannot only screen dislocations, but also play an important role on promoting hole injection into the MQWs. It is revealed that the injection of holes into the MQW via the sidewalls of the V-shaped pits is easier than via the flat region, due to the lower polarization charge densities in the sidewall structure with lower In concentration and (10–11)-oriented semi-polar facets.

Quantum key distribution network for multiple applications

NASA Astrophysics Data System (ADS)

Tajima, A.; Kondoh, T.; Ochi, T.; Fujiwara, M.; Yoshino, K.; Iizuka, H.; Sakamoto, T.; Tomita, A.; Shimamura, E.; Asami, S.; Sasaki, M.

2017-09-01

The fundamental architecture and functions of secure key management in a quantum key distribution (QKD) network with enhanced universal interfaces for smooth key sharing between arbitrary two nodes and enabling multiple secure communication applications are proposed. The proposed architecture consists of three layers: a quantum layer, key management layer and key supply layer. We explain the functions of each layer, the key formats in each layer and the key lifecycle for enabling a practical QKD network. A quantum key distribution-advanced encryption standard (QKD-AES) hybrid system and an encrypted smartphone system were developed as secure communication applications on our QKD network. The validity and usefulness of these systems were demonstrated on the Tokyo QKD Network testbed.

Multi-strategy based quantum cost reduction of linear nearest-neighbor quantum circuit

NASA Astrophysics Data System (ADS)

Tan, Ying-ying; Cheng, Xue-yun; Guan, Zhi-jin; Liu, Yang; Ma, Haiying

2018-03-01

With the development of reversible and quantum computing, study of reversible and quantum circuits has also developed rapidly. Due to physical constraints, most quantum circuits require quantum gates to interact on adjacent quantum bits. However, many existing quantum circuits nearest-neighbor have large quantum cost. Therefore, how to effectively reduce quantum cost is becoming a popular research topic. In this paper, we proposed multiple optimization strategies to reduce the quantum cost of the circuit, that is, we reduce quantum cost from MCT gates decomposition, nearest neighbor and circuit simplification, respectively. The experimental results show that the proposed strategies can effectively reduce the quantum cost, and the maximum optimization rate is 30.61% compared to the corresponding results.

Time Division Multiplexing of Semiconductor Qubits

NASA Astrophysics Data System (ADS)

Jarratt, Marie Claire; Hornibrook, John; Croot, Xanthe; Watson, John; Gardner, Geoff; Fallahi, Saeed; Manfra, Michael; Reilly, David

Readout chains, comprising resonators, amplifiers, and demodulators, are likely to be precious resources in quantum computing architectures. The potential to share readout resources is contingent on realising efficient means of time-division multiplexing (TDM) schemes that are compatible with quantum computing. Here, we demonstrate TDM using a GaAs quantum dot device with multiple charge sensors. Our device incorporates chip-level switches that do not load the impedance matching network. When used in conjunction with frequency multiplexing, each frequency tone addresses multiple time-multiplexed qubits, vastly increasing the capacity of a single readout line.

Multiple multicontrol unitary operations: Implementation and applications

NASA Astrophysics Data System (ADS)

Lin, Qing

2018-04-01

The efficient implementation of computational tasks is critical to quantum computations. In quantum circuits, multicontrol unitary operations are important components. Here, we present an extremely efficient and direct approach to multiple multicontrol unitary operations without decomposition to CNOT and single-photon gates. With the proposed approach, the necessary two-photon operations could be reduced from O( n 3) with the traditional decomposition approach to O( n), which will greatly relax the requirements and make large-scale quantum computation feasible. Moreover, we propose the potential application to the ( n- k)-uniform hypergraph state.

Detection of electromagnetic radiation using micromechanical multiple quantum wells structures

DOEpatents

Datskos, Panagiotis G [Knoxville, TN; Rajic, Slobodan [Knoxville, TN; Datskou, Irene [Knoxville, TN

2007-07-17

An apparatus and method for detecting electromagnetic radiation employs a deflectable micromechanical apparatus incorporating multiple quantum wells structures. When photons strike the quantum-well structure, physical stresses are created within the sensor, similar to a "bimetallic effect." The stresses cause the sensor to bend. The extent of deflection of the sensor can be measured through any of a variety of conventional means to provide a measurement of the photons striking the sensor. A large number of such sensors can be arranged in a two-dimensional array to provide imaging capability.

Optimum testing of multiple hypotheses in quantum detection theory

NASA Technical Reports Server (NTRS)

Yuen, H. P.; Kennedy, R. S.; Lax, M.

1975-01-01

The problem of specifying the optimum quantum detector in multiple hypotheses testing is considered for application to optical communications. The quantum digital detection problem is formulated as a linear programming problem on an infinite-dimensional space. A necessary and sufficient condition is derived by the application of a general duality theorem specifying the optimum detector in terms of a set of linear operator equations and inequalities. Existence of the optimum quantum detector is also established. The optimality of commuting detection operators is discussed in some examples. The structure and performance of the optimal receiver are derived for the quantum detection of narrow-band coherent orthogonal and simplex signals. It is shown that modal photon counting is asymptotically optimum in the limit of a large signaling alphabet and that the capacity goes to infinity in the absence of a bandwidth limitation.

Uncertainty relation for non-Hamiltonian quantum systems

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

Tarasov, Vasily E.

2013-01-15

General forms of uncertainty relations for quantum observables of non-Hamiltonian quantum systems are considered. Special cases of uncertainty relations are discussed. The uncertainty relations for non-Hamiltonian quantum systems are considered in the Schroedinger-Robertson form since it allows us to take into account Lie-Jordan algebra of quantum observables. In uncertainty relations, the time dependence of quantum observables and the properties of this dependence are discussed. We take into account that a time evolution of observables of a non-Hamiltonian quantum system is not an endomorphism with respect to Lie, Jordan, and associative multiplications.

A programmable quantum current standard from the Josephson and the quantum Hall effects

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

Poirier, W., E-mail: wilfrid.poirier@lne.fr; Lafont, F.; Djordjevic, S.

We propose a way to realize a programmable quantum current standard (PQCS) from the Josephson voltage standard and the quantum Hall resistance standard (QHR) exploiting the multiple connection technique provided by the quantum Hall effect (QHE) and the exactness of the cryogenic current comparator. The PQCS could lead to breakthroughs in electrical metrology like the realization of a programmable quantum current source, a quantum ampere-meter, and a simplified closure of the quantum metrological triangle. Moreover, very accurate universality tests of the QHE could be performed by comparing PQCS based on different QHRs.

Quantum Optimal Multiple Assignment Scheme for Realizing General Access Structure of Secret Sharing

NASA Astrophysics Data System (ADS)

Matsumoto, Ryutaroh

The multiple assignment scheme is to assign one or more shares to single participant so that any kind of access structure can be realized by classical secret sharing schemes. We propose its quantum version including ramp secret sharing schemes. Then we propose an integer optimization approach to minimize the average share size.

Use of external cavity quantum cascade laser compliance voltage in real-time trace gas sensing of multiple chemicals

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

Phillips, Mark C.; Taubman, Matthew S.; Kriesel, Jason M.

2015-02-08

We describe a prototype trace gas sensor designed for real-time detection of multiple chemicals. The sensor uses an external cavity quantum cascade laser (ECQCL) swept over its tuning range of 940-1075 cm-1 (9.30-10.7 µm) at a 10 Hz repetition rate.

Theoretical investigations of quantum correlations in NMR multiple-pulse spin-locking experiments

NASA Astrophysics Data System (ADS)

Gerasev, S. A.; Fedorova, A. V.; Fel'dman, E. B.; Kuznetsova, E. I.

2018-04-01

Quantum correlations are investigated theoretically in a two-spin system with the dipole-dipole interactions in the NMR multiple-pulse spin-locking experiments. We consider two schemes of the multiple-pulse spin-locking. The first scheme consists of π /2-pulses only and the delays between the pulses can differ. The second scheme contains φ-pulses (0<φ <π ) and has equal delays between them. We calculate entanglement for both schemes for an initial separable state. We show that entanglement is absent for the first scheme at equal delays between π /2-pulses at arbitrary temperatures. Entanglement emerges after several periods of the pulse sequence in the second scheme at φ =π /4 at milliKelvin temperatures. The necessary number of the periods increases with increasing temperature. We demonstrate the dependence of entanglement on the number of the periods of the multiple-pulse sequence. Quantum discord is obtained for the first scheme of the multiple-pulse spin-locking experiment at different temperatures.

Determination of dipole coupling constants using heteronuclear multiple quantum NMR

NASA Astrophysics Data System (ADS)

Weitekamp, D. P.; Garbow, J. R.; Pines, A.

1982-09-01

The problem of extracting dipole couplings from a system of N spins I = 1/2 and one spin S by NMR techniques is analyzed. The resolution attainable using a variety of single quantum methods is reviewed. The theory of heteronuclear multiple quantum (HMQ) NMR is developed, with particular emphasis being placed on the superior resolution available in HMQ spectra. Several novel pulse sequences are introduced, including a two-step method for the excitation of HMQ coherence. Experiments on partially oriented [1-13C] benzene demonstrate the excitation of the necessary HMQ coherence and illustrate the calculation of relative line intensities. Spectra of high order HMQ coherence under several different effective Hamiltonians achievable by multiple pulse sequences are discussed. A new effective Hamiltonian, scalar heteronuclear recoupled interactions by multiple pulse (SHRIMP), achieved by the simultaneous irradiation of both spin species with the same multiple pulse sequence, is introduced. Experiments are described which allow heteronuclear couplings to be correlated with an S-spin spreading parameter in spectra free of inhomogeneous broadening.

Quantum-enhanced metrology for multiple phase estimation with noise

PubMed Central

Yue, Jie-Dong; Zhang, Yu-Ran; Fan, Heng

2014-01-01

We present a general quantum metrology framework to study the simultaneous estimation of multiple phases in the presence of noise as a discretized model for phase imaging. This approach can lead to nontrivial bounds of the precision for multiphase estimation. Our results show that simultaneous estimation (SE) of multiple phases is always better than individual estimation (IE) of each phase even in noisy environment. The utility of the bounds of multiple phase estimation for photon loss channels is exemplified explicitly. When noise is low, those bounds possess the Heisenberg scale showing quantum-enhanced precision with the O(d) advantage for SE, where d is the number of phases. However, this O(d) advantage of SE scheme in the variance of the estimation may disappear asymptotically when photon loss becomes significant and then only a constant advantage over that of IE scheme demonstrates. Potential application of those results is presented. PMID:25090445

Mapping from multiple-control Toffoli circuits to linear nearest neighbor quantum circuits

NASA Astrophysics Data System (ADS)

Cheng, Xueyun; Guan, Zhijin; Ding, Weiping

2018-07-01

In recent years, quantum computing research has been attracting more and more attention, but few studies on the limited interaction distance between quantum bits (qubit) are deeply carried out. This paper presents a mapping method for transforming multiple-control Toffoli (MCT) circuits into linear nearest neighbor (LNN) quantum circuits instead of traditional decomposition-based methods. In order to reduce the number of inserted SWAP gates, a novel type of gate with the optimal LNN quantum realization was constructed, namely NNTS gate. The MCT gate with multiple control bits could be better cascaded by the NNTS gates, in which the arrangement of the input lines was LNN arrangement of the MCT gate. Then, the communication overhead measurement model on inserted SWAP gate count from the original arrangement to the new arrangement was put forward, and we selected one of the LNN arrangements with the minimum SWAP gate count. Moreover, the LNN arrangement-based mapping algorithm was given, and it dealt with the MCT gates in turn and mapped each MCT gate into its LNN form by inserting the minimum number of SWAP gates. Finally, some simplification rules were used, which can further reduce the final quantum cost of the LNN quantum circuit. Experiments on some benchmark MCT circuits indicate that the direct mapping algorithm results in fewer additional SWAP gates in about 50%, while the average improvement rate in quantum cost is 16.95% compared to the decomposition-based method. In addition, it has been verified that the proposed method has greater superiority for reversible circuits cascaded by MCT gates with more control bits.

Carrier multiplication and charge transport in artificial quantum-dot solids probed by ultrafast photocurrent spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Klimov, Victor I.

2017-05-01

Understanding and controlling carrier transport and recombination dynamics in colloidal quantum dot films is key to their application in electronic and optoelectronic devices. Towards this end, we have conducted transient photocurrent measurements to monitor transport through quantum confined band edge states in lead selenide quantum dots films as a function of pump fluence, temperature, electrical bias, and surface treatment. Room temperature dynamics reveal two distinct timescales of intra-dot geminate processes followed by non-geminate inter-dot processes. The non-geminate kinetics is well described by the recombination of holes with photoinjected and pre-existing electrons residing in mid-gap states. We find the mobility of the quantum-confined states shows no temperature dependence down to 6 K, indicating a tunneling mechanism of early time photoconductance. We present evidence of the importance of the exciton fine structure in controlling the low temperature photoconductance, whereby the nanoscale enhanced exchange interaction between electrons and holes in quantum dots introduces a barrier to charge separation. Finally, side-by-side comparison of photocurrent transients using excitation with low- and high-photon energies (1.5 vs. 3.0 eV) reveals clear signatures of carrier multiplication (CM), that is, generation of multiple excitons by single photons. Based on photocurrent measurements of quantum dot solids and optical measurements of solution based samples, we conclude that the CM efficiency is unaffected by strong inter-dot coupling. Therefore, the results of previous numerous spectroscopic CM studies conducted on dilute quantum dot suspensions should, in principle, be reproducible in electronically coupled QD films used in devices.

Computationally Efficient Nonlinear Bell Inequalities for Quantum Networks

NASA Astrophysics Data System (ADS)

Luo, Ming-Xing

2018-04-01

The correlations in quantum networks have attracted strong interest with new types of violations of the locality. The standard Bell inequalities cannot characterize the multipartite correlations that are generated by multiple sources. The main problem is that no computationally efficient method is available for constructing useful Bell inequalities for general quantum networks. In this work, we show a significant improvement by presenting new, explicit Bell-type inequalities for general networks including cyclic networks. These nonlinear inequalities are related to the matching problem of an equivalent unweighted bipartite graph that allows constructing a polynomial-time algorithm. For the quantum resources consisting of bipartite entangled pure states and generalized Greenberger-Horne-Zeilinger (GHZ) states, we prove the generic nonmultilocality of quantum networks with multiple independent observers using new Bell inequalities. The violations are maximal with respect to the presented Tsirelson's bound for Einstein-Podolsky-Rosen states and GHZ states. Moreover, these violations hold for Werner states or some general noisy states. Our results suggest that the presented Bell inequalities can be used to characterize experimental quantum networks.

Quantum teleportation of multiple degrees of freedom of a single photon

NASA Astrophysics Data System (ADS)

Wang, Xi-Lin; Cai, Xin-Dong; Su, Zu-En; Chen, Ming-Cheng; Wu, Dian; Li, Li; Liu, Nai-Le; Lu, Chao-Yang; Pan, Jian-Wei

2015-02-01

Quantum teleportation provides a `disembodied' way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom--internal and external--and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin-orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

Quantum teleportation of multiple degrees of freedom of a single photon.

PubMed

Wang, Xi-Lin; Cai, Xin-Dong; Su, Zu-En; Chen, Ming-Cheng; Wu, Dian; Li, Li; Liu, Nai-Le; Lu, Chao-Yang; Pan, Jian-Wei

2015-02-26

Quantum teleportation provides a 'disembodied' way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom--internal and external--and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin-orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

Effect of broad recombination zone in multiple quantum well structures on lifetime and efficiency of blue organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Lee, Seok Jae; Lee, Song Eun; Lee, Dong Hyung; Koo, Ja Ryong; Lee, Ho Won; Yoon, Seung Soo; Park, Jaehoon; Kim, Young Kwan

2014-10-01

Blue phosphorescent organic light-emitting diodes with multiple quantum well (MQW) structures (from one to four quantum wells) within an emitting layer (EML) are fabricated with charge control layers (CCLs) to control carrier movement. The distributed recombination zone and balanced charge carrier injection within EML are achieved through the MQW structure with CCLs. Remarkably, the half-decay lifetime of a blue device with three quantum wells, measured at an initial luminance of 500 cd/m2, is 3.5 times longer than that using a conventional structure. Additionally, the device’s efficiency improved. These results are explained with the effects of triplet exciton confinement and triplet-triplet annihilation within each EML.

Quantum caustics in resonance-fluorescence trajectories

NASA Astrophysics Data System (ADS)

Naghiloo, M.; Tan, D.; Harrington, P. M.; Lewalle, P.; Jordan, A. N.; Murch, K. W.

2017-11-01

We employ phase-sensitive amplification to perform homodyne detection of the resonance fluorescence from a driven superconducting artificial atom. Entanglement between the emitter and its fluorescence allows us to track the individual quantum state trajectories of the emitter conditioned on the outcomes of the field measurements. We analyze the ensemble properties of these trajectories by considering trajectories that connect specific initial and final states. By applying the stochastic path-integral formalism, we calculate equations of motion for the most-likely path between two quantum states and compare these predicted paths to experimental data. Drawing on the mathematical similarity between the action formalism of the most-likely quantum paths and ray optics, we study the emergence of caustics in quantum trajectories: places where multiple extrema in the stochastic action occur. We observe such multiple most-likely paths in experimental data and find these paths to be in reasonable quantitative agreement with theoretical calculations.

Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage.

PubMed

Kano, Shinya; Fujii, Minoru

2017-03-03

We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

Simultaneous detection of multiple DNA targets by integrating dual-color graphene quantum dot nanoprobes and carbon nanotubes.

PubMed

Qian, Zhaosheng; Shan, Xiaoyue; Chai, Lujing; Chen, Jianrong; Feng, Hui

2014-12-01

Simultaneous detection of multiple DNA targets was achieved based on a biocompatible graphene quantum dots (GQDs) and carbon nanotubes (CNTs) platform through spontaneous assembly between dual-color GQD-based probes and CNTs and subsequently self-recognition between DNA probes and targets. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PSA Converts Parathyroid Hormone-Related Protein (THrP) from an Osteolytic to an Osteoblastic Factor: Role in Bone Metastasis

DTIC Science & Technology

2004-12-01

bone density associated with DLX3 mutation in the tricho-dento-osseous syndrome . Bone. 35:988-997. Hassan MQ, Javed A, Morasso MI, Karlin J, Montecino M...putative role in hydrolysis of osteogenic peptides. J Bone Miner Res. 15:1266-1274. Ryan CW, Vogelzang NJ, Vokes EE, Kindler HL, Undevia SD, Humerickhouse

78 FR 67216 - Norfolk Southern Railway Company-Abandonment Exemption-in Lake County, Ind.

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... Junction Avenue in the City of Schererville, Ind.) and milepost MQ 283.10 (near the line's crossing of E... 14, 2014, or 10 days after service of a decision granting the petition for exemption, whichever occurs sooner. Each OFA must be accompanied by a $1,600 filing fee. See 49 CFR 1002.2(f)(25). All...

Extending Quad-Rotor UAV Autonomy with Onboard Image Processing

DTIC Science & Technology

2015-03-01

of this collection of information, including suggestions for reducing this burden, to Washington headquarters Services , Directorate for Information...vehicles perform a variety of tasks, from strike to surveillance to communications . Some vehicles, like the MQ-1 Predator, are operated remotely by...a human operator; others, like the BGM-109 Tomahawk cruise missile, can maneuver autonomously by following pre-programmed control law . Unmanned

Ion composition and upstream solar wind observations at comet Giacobini-Zinner

NASA Astrophysics Data System (ADS)

Coplan, M. A.; Ogilvie, K. W.; A'Hearn, M. F.; Bochsler, P.; Geiss, J.

1987-01-01

The observations by the ion composition instrument (ICI) on the ICE spacecraft made during the encounter with comet P/Giacobini-Zinner (Ogilvie et al., 1986) are discussed in detail. Solar wind He-4(2+) kinetic temperatures, densities, and velocities before, during, and after the encounter are presented. These data combined with He-4(2+) velocity distributions provide evidence for the existence of a thick diffuse shock. Relative abundances of water group ions and CO(+) are derived along with an estimate of the abundance of an ion with M/Q = 24 + or - 1 amu/e. The ICI data are compared with electron data from two other experiments (Bame et al., 1986; Meyer-Vernet et al., 1986) and found to be in reasonable agreement in the region outside the tail. Spectroscopic data for several neutral and ionic species are compared with the ICI results for the water group ions and CO(+). The spectroscopic data are also used to eliminate Mg(+) and CN(+) as candidates for the M/Q = 24 peak. The two most likely candidates are C2(+) and Na(+), but neither photoionization of parent neutrals nor sputtering from dust grains is sufficient to explain the observed abundance relative to H2O(+).

Survey of pickup ion signatures in the vicinity of Titan using CAPS/IMS

NASA Astrophysics Data System (ADS)

Regoli, L. H.; Coates, A. J.; Thomsen, M. F.; Jones, G. H.; Roussos, E.; Waite, J. H.; Krupp, N.; Cox, G.

2016-09-01

Pickup ion detection at Titan is challenging because ion cyclotron waves are rarely detected in the vicinity of the moon. In this work, signatures left by freshly produced pickup heavy ions (m/q ˜ 16 to m/q ˜ 28) as detected in the plasma data by the Cassini Plasma Spectrometer/Ion Mass Spectrometer (CAPS/IMS) instrument on board Cassini are analyzed. In order to discern whether these correspond to ions of exospheric origin, one of the flybys during which the reported signatures were observed is investigated in detail. For this purpose, ion composition data from time-of-flight measurements and test particle simulations to constrain the ions' origin are used. After being validated, the detection method is applied to all the flybys for which the CAPS/IMS instrument gathered valid data, constraining the region around the moon where the signatures are observed. The results reveal an escape region located in the anti-Saturn direction as expected from the nominal corotation electric field direction. These findings provide new constraints for the area of freshly produced pickup ion escape, giving an approximate escape rate of 3.3-2+3×1023 ions· s-1.

Thermal behavior of Charmonium in the vector channel from QCD sum rules

NASA Astrophysics Data System (ADS)

Dominguez, C. A.; Loewe, M.; Rojas, J. C.; Zhang, Y.

2010-11-01

The thermal evolution of the hadronic parameters of charmonium in the vector channel, i.e. the J/Ψ resonance mass, coupling (leptonic decay constant), total width, and continuum threshold are analyzed in the framework of thermal Hilbert moment QCD sum rules. The continuum threshold s0 has the same behavior as in all other hadronic channels, i.e. it decreases with increasing temperature until the PQCD threshold s0 = 4mQ2 is reached at T≃1.22Tc (mQ is the charm quark mass). The other hadronic parameters behave in a very different way from those of light-light and heavy-light quark systems. The J/Ψ mass is essentially constant in a wide range of temperatures, while the total width grows with temperature up to T≃1.04Tc beyond which it decreases sharply with increasing T. The resonance coupling is also initially constant beginning to increase monotonically around T≃Tc. This behavior of the total width and of the leptonic decay constant is a strong indication that the J/Ψ resonance might survive beyond the critical temperature for deconfinement, in agreement with some recent lattice QCD results.

Methodological quality is underrated in systematic reviews and meta-analyses in health psychology.

PubMed

Oliveras, Isabel; Losilla, Josep-Maria; Vives, Jaume

2017-06-01

In this paper, we compile and describe the main approaches proposed in the literature to include methodological quality (MQ) or risk of bias (RoB) into research synthesis. We also meta-review how the RoB of observational primary studies is being assessed and to what extent the results are incorporated in the conclusions of research synthesis. Electronic databases were searched for systematic reviews or meta-analyses related to health and clinical psychology. A random sample of 90 reviews published between January 2010 and May 2016 was examined. A total of 46 reviews (51%) performed a formal assessment of the RoB of primary studies. Only 17 reviews (19%) linked the outcomes of quality assessment with the results of the review. According to the previous literature, our results corroborate the lack of guidance to incorporate the RoB assessment in the results of systematic reviews and meta-analyses. Our recommendation is to appraise MQ according to domains of RoB to rate the degree of credibility of the results of a research synthesis, as well as subgroup analysis or meta-regression as analytical methods to incorporate the quality assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

Partially entangled states bridge in quantum teleportation

NASA Astrophysics Data System (ADS)

Cai, Xiao-Fei; Yu, Xu-Tao; Shi, Li-Hui; Zhang, Zai-Chen

2014-10-01

The traditional method for information transfer in a quantum communication system using partially entangled state resource is quantum distillation or direct teleportation. In order to reduce the waiting time cost in hop-by-hop transmission and execute independently in each node, we propose a quantum bridging method with partially entangled states to teleport quantum states from source node to destination node. We also prove that the designed specific quantum bridging circuit is feasible for partially entangled states teleportation across multiple intermediate nodes. Compared to two traditional ways, our partially entanglement quantum bridging method uses simpler logic gates, has better security, and can be used in less quantum resource situation.

Two new constructions of approximately SIC-POVMs from multiplicative characters

NASA Astrophysics Data System (ADS)

Luo, Gaojun; Cao, Xiwang

2017-12-01

In quantum information theory, symmetric informationally complete positive operator-valued measures (SIC-POVMs) are relevant to quantum state tomography [8], quantum cryptography [15], and foundational studies [16]. In general, it is hard to construct SIC-POVMs and only a few classes of them existed, as we know. Moreover, we do not know whether there exists an infinite class of them. Many researchers tried to construct approximately symmetric informationally complete positive operator-valued measures (ASIC-POVMs). In this paper, we propose two new constructions of ASIC-POVMs for prime power dimensions only by using multiplicative characters over finite fields.

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

Baart, T. A.; Vandersypen, L. M. K.; Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft

We report the computer-automated tuning of gate-defined semiconductor double quantum dots in GaAs heterostructures. We benchmark the algorithm by creating three double quantum dots inside a linear array of four quantum dots. The algorithm sets the correct gate voltages for all the gates to tune the double quantum dots into the single-electron regime. The algorithm only requires (1) prior knowledge of the gate design and (2) the pinch-off value of the single gate T that is shared by all the quantum dots. This work significantly alleviates the user effort required to tune multiple quantum dot devices.

Students' Conceptual Difficulties in Quantum Mechanics: Potential Well Problems

ERIC Educational Resources Information Center

Ozcan, Ozgur; Didis, Nilufer; Tasar, Mehmet Fatih

2009-01-01

In this study, students' conceptual difficulties about some basic concepts in quantum mechanics like one-dimensional potential well problems and probability density of tunneling particles were identified. For this aim, a multiple choice instrument named Quantum Mechanics Conceptual Test has been developed by one of the researchers of this study…

Quantum communication beyond the localization length in disordered spin chains.

PubMed

Allcock, Jonathan; Linden, Noah

2009-03-20

We study the effects of localization on quantum state transfer in spin chains. We show how to use quantum error correction and multiple parallel spin chains to send a qubit with high fidelity over arbitrary distances, in particular, distances much greater than the localization length of the chain.

Electrically Tunable Terahertz Quantum-Cascade Lasers

NASA Technical Reports Server (NTRS)

Gunapala, Sarath; Soidel, Alexander; Mansour, Kamjou

2006-01-01

Improved quantum-cascade lasers (QCLs) are being developed as electrically tunable sources of radiation in the far infrared spectral region, especially in the frequency range of 2 to 5 THz. The structures of QCLs and the processes used to fabricate them have much in common with those of multiple- quantum-well infrared photodetectors.

Simultaneous nano-tracking of multiple motor proteins via spectral discrimination of quantum dots.

PubMed

Kakizuka, Taishi; Ikezaki, Keigo; Kaneshiro, Junichi; Fujita, Hideaki; Watanabe, Tomonobu M; Ichimura, Taro

2016-07-01

Simultaneous nanometric tracking of multiple motor proteins was achieved by combining multicolor fluorescent labeling of target proteins and imaging spectroscopy, revealing dynamic behaviors of multiple motor proteins at the sub-diffraction-limit scale. Using quantum dot probes of distinct colors, we experimentally verified the localization precision to be a few nanometers at temporal resolution of 30 ms or faster. One-dimensional processive movement of two heads of a single myosin molecule and multiple myosin molecules was successfully traced. Furthermore, the system was modified for two-dimensional measurement and applied to tracking of multiple myosin molecules. Our approach is useful for investigating cooperative movement of proteins in supramolecular nanomachinery.

Simultaneous nano-tracking of multiple motor proteins via spectral discrimination of quantum dots

PubMed Central

Kakizuka, Taishi; Ikezaki, Keigo; Kaneshiro, Junichi; Fujita, Hideaki; Watanabe, Tomonobu M.; Ichimura, Taro

2016-01-01

Simultaneous nanometric tracking of multiple motor proteins was achieved by combining multicolor fluorescent labeling of target proteins and imaging spectroscopy, revealing dynamic behaviors of multiple motor proteins at the sub-diffraction-limit scale. Using quantum dot probes of distinct colors, we experimentally verified the localization precision to be a few nanometers at temporal resolution of 30 ms or faster. One-dimensional processive movement of two heads of a single myosin molecule and multiple myosin molecules was successfully traced. Furthermore, the system was modified for two-dimensional measurement and applied to tracking of multiple myosin molecules. Our approach is useful for investigating cooperative movement of proteins in supramolecular nanomachinery. PMID:27446684

Quantum cryptography and applications in the optical fiber network

NASA Astrophysics Data System (ADS)

Luo, Yuhui

2005-09-01

Quantum cryptography, as part of quantum information and communications, can provide absolute security for information transmission because it is established on the fundamental laws of quantum theory, such as the principle of uncertainty, No-cloning theorem and quantum entanglement. In this thesis research, a novel scheme to implement quantum key distribution based on multiphoton entanglement with a new protocol is proposed. Its advantages are: a larger information capacity can be obtained with a longer transmission distance and the detection of multiple photons is easier than that of a single photon. The security and attacks pertaining to such a system are also studied. Next, a quantum key distribution over wavelength division multiplexed (WDM) optical fiber networks is realized. Quantum key distribution in networks is a long-standing problem for practical applications. Here we combine quantum cryptography and WDM to solve this problem because WDM technology is universally deployed in the current and next generation fiber networks. The ultimate target is to deploy quantum key distribution over commercial networks. The problems arising from the networks are also studied in this part. Then quantum key distribution in multi-access networks using wavelength routing technology is investigated in this research. For the first time, quantum cryptography for multiple individually targeted users has been successfully implemented in sharp contrast to that using the indiscriminating broadcasting structure. It overcomes the shortcoming that every user in the network can acquire the quantum key signals intended to be exchanged between only two users. Furthermore, a more efficient scheme of quantum key distribution is adopted, hence resulting in a higher key rate. Lastly, a quantum random number generator based on quantum optics has been experimentally demonstrated. This device is a key component for quantum key distribution as it can create truly random numbers, which is an essential requirement to perform quantum key distribution. This new generator is composed of a single optical fiber coupler with fiber pigtails, which can be easily used in optical fiber communications.

Optoelectronic Performance Variations in InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes: Effects of Potential Fluctuation.

PubMed

Islam, Abu Bashar Mohammad Hamidul; Shim, Jong-In; Shin, Dong-Soo

2018-05-07

We investigate the cause of the optoelectronic performance variations in InGaN/GaN multiple-quantum-well blue light-emitting diodes, using three different samples from an identical wafer grown on a c -plane sapphire substrate. Various macroscopic measurements have been conducted, revealing that with increasing strain in the quantum wells (QWs), the crystal quality improves with an increasing peak internal quantum efficiency while the droop becomes more severe. We propose to explain these variations using a model where the in-plane local potential fluctuation in QWs is considered. Our work is contrasted with prior works in that macroscopic measurements are utilized to find clues on the microscopic changes and their impacts on the device performances, which has been rarely attempted.

Code-division multiple-access multiuser demodulator by using quantum fluctuations.

PubMed

Otsubo, Yosuke; Inoue, Jun-Ichi; Nagata, Kenji; Okada, Masato

2014-07-01

We examine the average-case performance of a code-division multiple-access (CDMA) multiuser demodulator in which quantum fluctuations are utilized to demodulate the original message within the context of Bayesian inference. The quantum fluctuations are built into the system as a transverse field in the infinite-range Ising spin glass model. We evaluate the performance measurements by using statistical mechanics. We confirm that the CDMA multiuser modulator using quantum fluctuations achieve roughly the same performance as the conventional CDMA multiuser modulator through thermal fluctuations on average. We also find that the relationship between the quality of the original information retrieval and the amplitude of the transverse field is somehow a "universal feature" in typical probabilistic information processing, viz., in image restoration, error-correcting codes, and CDMA multiuser demodulation.

Code-division multiple-access multiuser demodulator by using quantum fluctuations

NASA Astrophysics Data System (ADS)

Otsubo, Yosuke; Inoue, Jun-ichi; Nagata, Kenji; Okada, Masato

2014-07-01

We examine the average-case performance of a code-division multiple-access (CDMA) multiuser demodulator in which quantum fluctuations are utilized to demodulate the original message within the context of Bayesian inference. The quantum fluctuations are built into the system as a transverse field in the infinite-range Ising spin glass model. We evaluate the performance measurements by using statistical mechanics. We confirm that the CDMA multiuser modulator using quantum fluctuations achieve roughly the same performance as the conventional CDMA multiuser modulator through thermal fluctuations on average. We also find that the relationship between the quality of the original information retrieval and the amplitude of the transverse field is somehow a "universal feature" in typical probabilistic information processing, viz., in image restoration, error-correcting codes, and CDMA multiuser demodulation.

Local Gate Control of a Carbon Nanotube Double Quantum Dot

DTIC Science & Technology

2016-04-04

Nanotube Double Quantum Dot N. Mason,*† M. J. Biercuk,* C. M. Marcus† We have measured carbon nanotube quantum dots with multiple electro- static gates and...computation. Carbon nanotubes have been considered lead- ing candidates for nanoscale electronic applica- tions (1, 2). Previous measurements of nano- tube...electronics have shown electron confine- ment (quantum dot) effects such as single- electron charging and energy-level quantization (3–5). Nanotube

Controllably releasing long-lived quantum memory for photonic polarization qubit into multiple spatially-separate photonic channels.

PubMed

Chen, Lirong; Xu, Zhongxiao; Zeng, Weiqing; Wen, Yafei; Li, Shujing; Wang, Hai

2016-09-26

We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple spatially-separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel. By changing the propagating directions of the read laser beam, we controllably release the retrieved PPQs into 7 different photonic output channels, respectively. At a storage time of δt = 5 μs, the least quantum-process fidelity in 7 different output channels is ~89%. At one of the output channels, the measured maximum quantum-process fidelity for the PPQs is 94.2% at storage time of δt = 0.85 ms. At storage time of 6 ms, the quantum-process fidelity is still beyond the bound of 78% to violate the Bell's inequality. The demonstrated controllable release of the stored PPQs may extend the capabilities of the quantum information storage technique.

Coherent optical pulse sequencer for quantum applications.

PubMed

Hosseini, Mahdi; Sparkes, Ben M; Hétet, Gabriel; Longdell, Jevon J; Lam, Ping Koy; Buchler, Ben C

2009-09-10

The bandwidth and versatility of optical devices have revolutionized information technology systems and communication networks. Precise and arbitrary control of an optical field that preserves optical coherence is an important requisite for many proposed photonic technologies. For quantum information applications, a device that allows storage and on-demand retrieval of arbitrary quantum states of light would form an ideal quantum optical memory. Recently, significant progress has been made in implementing atomic quantum memories using electromagnetically induced transparency, photon echo spectroscopy, off-resonance Raman spectroscopy and other atom-light interaction processes. Single-photon and bright-optical-field storage with quantum states have both been successfully demonstrated. Here we present a coherent optical memory based on photon echoes induced through controlled reversible inhomogeneous broadening. Our scheme allows storage of multiple pulses of light within a chosen frequency bandwidth, and stored pulses can be recalled in arbitrary order with any chosen delay between each recalled pulse. Furthermore, pulses can be time-compressed, time-stretched or split into multiple smaller pulses and recalled in several pieces at chosen times. Although our experimental results are so far limited to classical light pulses, our technique should enable the construction of an optical random-access memory for time-bin quantum information, and have potential applications in quantum information processing.

Progress on Ultra-Dense Quantum Communication Using Integrated Photonic Architecture

DTIC Science & Technology

2013-01-01

entanglement based quantum key distribution . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Extended dispersive-optics QKD (DO-QKD) protocol...2 2.3 Analysis of non-local correlations of entangled photon pairs for arbitrary dis- persion...Section 3). 2 Protocol Development 2.1 Achieving multiple secure bits per coincidence in time-energy entanglement based quantum key distribution High

The operator algebra approach to quantum groups

PubMed Central

Kustermans, Johan; Vaes, Stefaan

2000-01-01

A relatively simple definition of a locally compact quantum group in the C*-algebra setting will be explained as it was recently obtained by the authors. At the same time, we put this definition in the historical and mathematical context of locally compact groups, compact quantum groups, Kac algebras, multiplicative unitaries, and duality theory. PMID:10639116

Quantum game application to spectrum scarcity problems

NASA Astrophysics Data System (ADS)

Zabaleta, O. G.; Barrangú, J. P.; Arizmendi, C. M.

2017-01-01

Recent spectrum-sharing research has produced a strategy to address spectrum scarcity problems. This novel idea, named cognitive radio, considers that secondary users can opportunistically exploit spectrum holes left temporarily unused by primary users. This presents a competitive scenario among cognitive users, making it suitable for game theory treatment. In this work, we show that the spectrum-sharing benefits of cognitive radio can be increased by designing a medium access control based on quantum game theory. In this context, we propose a model to manage spectrum fairly and effectively, based on a multiple-users multiple-choice quantum minority game. By taking advantage of quantum entanglement and quantum interference, it is possible to reduce the probability of collision problems commonly associated with classic algorithms. Collision avoidance is an essential property for classic and quantum communications systems. In our model, two different scenarios are considered, to meet the requirements of different user strategies. The first considers sensor networks where the rational use of energy is a cornerstone; the second focuses on installations where the quality of service of the entire network is a priority.

Beverage Selections and Impact on Healthy Eating Index Scores in Elementary Children's Lunches from School and from Home

ERIC Educational Resources Information Center

Bergman, Ethan A.; Englund, Tim; Ogan, Dana; Watkins, Tracee; Barbee, Mary; Rushing, Keith

2016-01-01

Purpose/Objectives: The purposes of this study were to: 1) analyze beverage selections of elementary students consuming National School Lunch Program meals (NSLP) and lunches brought from home (LBFH), 2) compare overall meal quality (MQ) of NSLP and LBFH by food components using Healthy Eating Index 2010 (HEI-2010), and 3) investigate the impact…

Statistical Methods, Some Old, Some New: A Tutorial Survey.

DTIC Science & Technology

1981-01-01

Ext I Z - MExt I Ext SExt \\2 Ext-Ext The quartile (eighth, extreme) means MQ(ME,.MExt) can be quickly compared to M to detect systematic asymmetry or...summary then is 3! Q r2 31 1 60_ 30 -6 0.43 I 11 - 130 - 656 I ill SExt III-1 = 0.45 The numbers suggest positive skewness, but closer examination reveals

Geometric descriptions of entangled states by auxiliary varieties

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

Holweck, Frederic; Luque, Jean-Gabriel; Thibon, Jean-Yves

2012-10-15

The aim of the paper is to propose geometric descriptions of multipartite entangled states using algebraic geometry. In the context of this paper, geometric means each stratum of the Hilbert space, corresponding to an entangled state, is an open subset of an algebraic variety built by classical geometric constructions (tangent lines, secant lines) from the set of separable states. In this setting, we describe well-known classifications of multipartite entanglement such as 2 Multiplication-Sign 2 Multiplication-Sign (n+ 1), for n Greater-Than-Or-Slanted-Equal-To 1, quantum systems and a new description with the 2 Multiplication-Sign 3 Multiplication-Sign 3 quantum system. Our results complete themore » approach of Miyake and make stronger connections with recent work of algebraic geometers. Moreover, for the quantum systems detailed in this paper, we propose an algorithm, based on the classical theory of invariants, to decide to which subvariety of the Hilbert space a given state belongs.« less

Guidelines on "Standards of management of idiopathic scoliosis with corrective braces in everyday clinics and in clinical research": SOSORT Consensus 2008

PubMed Central

Negrini, Stefano; Grivas, Theodoros B; Kotwicki, Tomasz; Rigo, Manuel; Zaina, Fabio

2009-01-01

Background Reported failure rates,(defined based on percentage of cases progressing to surgery) of corrective bracing for idiopathic scoliosis are highly variable. This may be due to the quality of the brace itself, but also of the patient care during treatment. The latter is sometimes neglected, even though it is considered a main determinant of good results among conservative experts of SOSORT. The aim of this paper was to develop and verify the Consensus on management of scoliosis patients treated with braces Methods We followed a Delphi process in four steps, distributing and gradually changing according to the results a set of recommendations: we involved the SOSORT Board twice, then all SOSORT members twice, with a Pre-Meeting Questionnaire (PMQ), and during a Consensus Session at the SOSORT Athens Meeting with a Meeting Questionnaire (MQ). We set a 90% agreement as the minimum to be reached. Results We had a 71% response rate to PMQ, and 66.7% to MQ. Since the PMQ we had a good agreement (no answers below 72% – 70.2% over 90%). With the MQ the agreement consistently increased for all the answers previously below 90% (no answers below 83%, 75% over 90%). With increasing experience in bracing all numerical criteria tended to become more strict. We finally produced a set of 14 recommendations, grouped in 6 Domains (Experience/competence, Behaviours, Prescription, Construction, Brace Check, Follow-up). Conclusion The Consensus permits establishment of recommendations concerning the standards of management of idiopathic scoliosis with bracing, with the aim to increase efficacy and compliance to treatment. The SOSORT recommends to professionals engaged in patient care to follow the guidelines of this Consensus in their clinical practice. The SOSORT criteria should also be followed in clinical research studies to achieve a minimum quality of care. If the aim is to verify the efficacy of bracing these criteria should be companions of the methodological research criteria for bracing proposed by other societies. PMID:19149877

Effects of elastic resistance exercise on body composition and physical capacity in older women with sarcopenic obesity

PubMed Central

Liao, Chun-De; Tsauo, Jau-Yih; Lin, Li-Fong; Huang, Shih-Wei; Ku, Jan-Wen; Chou, Lin-Chuan; Liou, Tsan-Hon

2017-01-01

Abstract Background: Sarcopenia is associated with loss of muscle mass and an increased risk of physical disability in elderly people. However, the prevalence of sarcopenia has increased in obese elderly populations. The purpose of this study was to identify the clinical efficacy of elastic resistance exercise training (RET) in patients with sarcopenic obesity. Methods: This study was conducted at the rehabilitation center of a university-based teaching hospital and was designed as a prospective and randomized controlled trial with an intention-to-treat analysis. A total of 46 women aged 67.3 (5.2) years were randomly assigned to an experimental group (EG) and control group (CG). The EG underwent elastic RET for 12 weeks, and the CG received no RET intervention. All outcome measures were assessed at the baseline and posttest, including body composition measured using dual-energy X-ray absorptiometry, muscle quality (MQ) defined as a ratio of muscular strength to muscle mass, and physical capacity assessed using functional mobility tests. One-way analysis of covariance and Pearson correlation were used to compare outcomes between the 2 groups and to identify the relationship between changes in body composition and physical outcomes, respectively. A chi-square test was performed to identify differences in qualitative data between the 2 groups. Results: At the posttest, a significant between-group difference was observed in fat-free mass, MQ, and physical capacity (all P < .05); and a significant correlation was found between leg-lean-mass change and gait speed (r = 0.36; P < .05). After 12 weeks of elastic RET intervention, the EG had significantly fewer patients exhibiting sarcopenia (P < .05) and experiencing physical difficulty (P < .001) than the CG. Conclusion: The present data suggest that elastic resistance exercise exerted benefits on the body composition, MQ, and physical function in patients with sarcopenic obesity. Regular exercise incorporating elastic RET should be used to attenuate muscle mass loss and prevent physical difficulty in obese older adults with sarcopenia on reconditioning therapy. Trial Registration: Chinese Clinical Trial Registry, ChiCTR-IPR-15006069. PMID:28591061

Statistical precision of the intensities retrieved from constrained fitting of overlapping peaks in high-resolution mass spectra

DOE PAGES

Cubison, M. J.; Jimenez, J. L.

2015-06-05

Least-squares fitting of overlapping peaks is often needed to separately quantify ions in high-resolution mass spectrometer data. A statistical simulation approach is used to assess the statistical precision of the retrieved peak intensities. The sensitivity of the fitted peak intensities to statistical noise due to ion counting is probed for synthetic data systems consisting of two overlapping ion peaks whose positions are pre-defined and fixed in the fitting procedure. The fitted intensities are sensitive to imperfections in the m/Q calibration. These propagate as a limiting precision in the fitted intensities that may greatly exceed the precision arising from counting statistics.more » The precision on the fitted peak intensity falls into one of three regimes. In the "counting-limited regime" (regime I), above a peak separation χ ~ 2 to 3 half-widths at half-maximum (HWHM), the intensity precision is similar to that due to counting error for an isolated ion. For smaller χ and higher ion counts (~ 1000 and higher), the intensity precision rapidly degrades as the peak separation is reduced ("calibration-limited regime", regime II). Alternatively for χ < 1.6 but lower ion counts (e.g. 10–100) the intensity precision is dominated by the additional ion count noise from the overlapping ion and is not affected by the imprecision in the m/Q calibration ("overlapping-limited regime", regime III). The transition between the counting and m/Q calibration-limited regimes is shown to be weakly dependent on resolving power and data spacing and can thus be approximated by a simple parameterisation based only on peak intensity ratios and separation. A simple equation can be used to find potentially problematic ion pairs when evaluating results from fitted spectra containing many ions. Longer integration times can improve the precision in regimes I and III, but a given ion pair can only be moved out of regime II through increased spectrometer resolving power. As a result, studies presenting data obtained from least-squares fitting procedures applied to mass spectral peaks should explicitly consider these limits on statistical precision.« less

Effects of elastic resistance exercise on body composition and physical capacity in older women with sarcopenic obesity: A CONSORT-compliant prospective randomized controlled trial.

PubMed

Liao, Chun-De; Tsauo, Jau-Yih; Lin, Li-Fong; Huang, Shih-Wei; Ku, Jan-Wen; Chou, Lin-Chuan; Liou, Tsan-Hon

2017-06-01

Sarcopenia is associated with loss of muscle mass and an increased risk of physical disability in elderly people. However, the prevalence of sarcopenia has increased in obese elderly populations. The purpose of this study was to identify the clinical efficacy of elastic resistance exercise training (RET) in patients with sarcopenic obesity. This study was conducted at the rehabilitation center of a university-based teaching hospital and was designed as a prospective and randomized controlled trial with an intention-to-treat analysis. A total of 46 women aged 67.3 (5.2) years were randomly assigned to an experimental group (EG) and control group (CG). The EG underwent elastic RET for 12 weeks, and the CG received no RET intervention. All outcome measures were assessed at the baseline and posttest, including body composition measured using dual-energy X-ray absorptiometry, muscle quality (MQ) defined as a ratio of muscular strength to muscle mass, and physical capacity assessed using functional mobility tests. One-way analysis of covariance and Pearson correlation were used to compare outcomes between the 2 groups and to identify the relationship between changes in body composition and physical outcomes, respectively. A chi-square test was performed to identify differences in qualitative data between the 2 groups. At the posttest, a significant between-group difference was observed in fat-free mass, MQ, and physical capacity (all P < .05); and a significant correlation was found between leg-lean-mass change and gait speed (r = 0.36; P < .05). After 12 weeks of elastic RET intervention, the EG had significantly fewer patients exhibiting sarcopenia (P < .05) and experiencing physical difficulty (P < .001) than the CG. The present data suggest that elastic resistance exercise exerted benefits on the body composition, MQ, and physical function in patients with sarcopenic obesity. Regular exercise incorporating elastic RET should be used to attenuate muscle mass loss and prevent physical difficulty in obese older adults with sarcopenia on reconditioning therapy. Chinese Clinical Trial Registry, ChiCTR-IPR-15006069.

Upper bounds on the error probabilities and asymptotic error exponents in quantum multiple state discrimination

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

Audenaert, Koenraad M. R., E-mail: koenraad.audenaert@rhul.ac.uk; Department of Physics and Astronomy, University of Ghent, S9, Krijgslaan 281, B-9000 Ghent; Mosonyi, Milán, E-mail: milan.mosonyi@gmail.com

2014-10-01

We consider the multiple hypothesis testing problem for symmetric quantum state discrimination between r given states σ₁, …, σ{sub r}. By splitting up the overall test into multiple binary tests in various ways we obtain a number of upper bounds on the optimal error probability in terms of the binary error probabilities. These upper bounds allow us to deduce various bounds on the asymptotic error rate, for which it has been hypothesized that it is given by the multi-hypothesis quantum Chernoff bound (or Chernoff divergence) C(σ₁, …, σ{sub r}), as recently introduced by Nussbaum and Szkoła in analogy with Salikhov'smore » classical multi-hypothesis Chernoff bound. This quantity is defined as the minimum of the pairwise binary Chernoff divergences min{sub j« less

Microwave spectroscopic observation of multiple phase transitions in the bilayer electron solid in wide quantum wells

NASA Astrophysics Data System (ADS)

Hatke, Anthony; Engel, Lloyd; Liu, Yang; Shayegan, Mansour; Pfeiffer, Loren; West, Ken; Baldwin, Kirk

2015-03-01

The termination of the low Landau filling factor (ν) fractional quantum Hall series for a single layer two dimensional system results in the formation of a pinned Wigner solid for ν < 1 / 5. In a wide quantum well the system can support a bilayer state in which interlayer and intralayer interactions become comparable, which is measured in traditional transport as an insulating state for ν < 1 / 2. We perform microwave spectroscopic studies of this bilayer state and observe that this insulator exhibits a resonance, a signature of a solid phase. Additionally, we find that as we increase the density of the well at fixed ν this bilayer solid exhibits multiple sharp reductions in the resonance amplitude vs ν. This behavior is characteristic of multiple phase transitions, which remain hidden from dc transport measurements.

A noise immunity controlled quantum teleportation protocol

NASA Astrophysics Data System (ADS)

Li, Dong-fen; Wang, Rui-jin; Zhang, Feng-li; Baagyere, Edward; Qin, Zhen; Xiong, Hu; Zhan, Huayi

2016-11-01

With the advent of the Internet and information and communication technology, quantum teleportation has become an important field in information security and its application areas. This is because quantum teleportation has the ability to attain a timely secret information delivery and offers unconditional security. And as such, the field of quantum teleportation has become a hot research topic in recent years. However, noise has serious effect on the safety of quantum teleportation within the aspects of information fidelity, channel capacity and information transfer. Therefore, the main purpose of this paper is to address these problems of quantum teleportation. Firstly, in order to resist collective noise, we construct a decoherence-free subspace under different noise scenarios to establish a two-dimensional fidelity quantum teleportation models. And also create quantum teleportation of multiple degree of freedom, and these models ensure the accuracy and availability of the exchange of information and in multiple degree of freedom. Secondly, for easy preparation, measurement and implementation, we use super dense coding features to build an entangled quantum secret exchange channel. To improve the channel utilization and capacity, an efficient super dense coding method based on ultra-entanglement exchange is used. Thirdly, continuous variables of the controlled quantum key distribution were designed for quantum teleportation; in addition, we perform Bell-basis measurement under the collective noise and also prepare the storage technology of quantum states to achieve one-bit key by three-photon encoding to improve its security and efficiency. We use these two methods because they conceal information, resist a third party attack and can detect eavesdropping. Our proposed methods, according to the security analysis, are able to solve the problems associated with the quantum teleportation under various noise environments.

Quantum partial search for uneven distribution of multiple target items

NASA Astrophysics Data System (ADS)

Zhang, Kun; Korepin, Vladimir

2018-06-01

Quantum partial search algorithm is an approximate search. It aims to find a target block (which has the target items). It runs a little faster than full Grover search. In this paper, we consider quantum partial search algorithm for multiple target items unevenly distributed in a database (target blocks have different number of target items). The algorithm we describe can locate one of the target blocks. Efficiency of the algorithm is measured by number of queries to the oracle. We optimize the algorithm in order to improve efficiency. By perturbation method, we find that the algorithm runs the fastest when target items are evenly distributed in database.

Quantum Darwinism

NASA Astrophysics Data System (ADS)

Zurek, Wojciech Hubert

2009-03-01

Quantum Darwinism describes the proliferation, in the environment, of multiple records of selected states of a quantum system. It explains how the quantum fragility of a state of a single quantum system can lead to the classical robustness of states in their correlated multitude; shows how effective `wave-packet collapse' arises as a result of the proliferation throughout the environment of imprints of the state of the system; and provides a framework for the derivation of Born's rule, which relates the probabilities of detecting states to their amplitudes. Taken together, these three advances mark considerable progress towards settling the quantum measurement problem.

Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics

NASA Astrophysics Data System (ADS)

Kockum, Anton Frisk; Johansson, Göran; Nori, Franco

2018-04-01

In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2N states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.

Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics.

PubMed

Kockum, Anton Frisk; Johansson, Göran; Nori, Franco

2018-04-06

In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2^{N} states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.

Triazatruxene: A Rigid Central Donor Unit for a D-A3 Thermally Activated Delayed Fluorescence Material Exhibiting Sub-Microsecond Reverse Intersystem Crossing and Unity Quantum Yield via Multiple Singlet-Triplet State Pairs.

PubMed

Dos Santos, Paloma L; Ward, Jonathan S; Congrave, Daniel G; Batsanov, Andrei S; Eng, Julien; Stacey, Jessica E; Penfold, Thomas J; Monkman, Andrew P; Bryce, Martin R

2018-06-01

By inverting the common structural motif of thermally activated delayed fluorescence materials to a rigid donor core and multiple peripheral acceptors, reverse intersystem crossing (rISC) rates are demonstrated in an organic material that enables utilization of triplet excited states at faster rates than Ir-based phosphorescent materials. A combination of the inverted structure and multiple donor-acceptor interactions yields up to 30 vibronically coupled singlet and triplet states within 0.2 eV that are involved in rISC. This gives a significant enhancement to the rISC rate, leading to delayed fluorescence decay times as low as 103.9 ns. This new material also has an emission quantum yield ≈1 and a very small singlet-triplet gap. This work shows that it is possible to achieve both high photoluminescence quantum yield and fast rISC in the same molecule. Green organic light-emitting diode devices with external quantum efficiency >30% are demonstrated at 76 cd m -2 .

Polarizabilities of Impurity Doped Quantum Dots Under Pulsed Field: Role of Multiplicative White Noise

NASA Astrophysics Data System (ADS)

Saha, Surajit; Ghosh, Manas

2016-02-01

We perform a rigorous analysis of the profiles of a few diagonal and off-diagonal components of linear ( α xx , α yy , α xy , and α yx ), first nonlinear ( β xxx , β yyy , β xyy , and β yxx ), and second nonlinear ( γ xxxx , γ yyyy , γ xxyy , and γ yyxx ) polarizabilities of quantum dots exposed to an external pulsed field. Simultaneous presence of multiplicative white noise has also been taken into account. The quantum dot contains a dopant represented by a Gaussian potential. The number of pulse and the dopant location have been found to fabricate the said profiles through their interplay. Moreover, a variation in the noise strength also contributes evidently in designing the profiles of above polarizability components. In general, the off-diagonal components have been found to be somewhat more responsive to a variation of noise strength. However, we have found some exception to the above fact for the off-diagonal β yxx component. The study projects some pathways of achieving stable, enhanced, and often maximized output of linear and nonlinear polarizabilities of doped quantum dots driven by multiplicative noise.

A multi-pathway model for photosynthetic reaction center

NASA Astrophysics Data System (ADS)

Qin, M.; Shen, H. Z.; Yi, X. X.

2016-03-01

Charge separation occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine. Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem II reaction center (PSII RC) to describe the charge separation. Our model mainly considers two charge-separation pathways which is more than that typically considered in the published literature. We explore how these cross-couplings increase the current and power of the charge separation and discuss the effects of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PSII RC and dephasing induced by environments is also explored, and extension from two pathways to multiple pathways is made. These results suggest that noise-induced quantum coherence helps to suppress the influence of acceptor-to-donor charge recombination, and besides, nature-mimicking architectures with engineered multiple pathways for charge separations might be better for artificial solar energy devices considering the influence of environments.

Interface circuit for a multiple-beam tuning-fork gyroscope with high quality factors

NASA Astrophysics Data System (ADS)

Wang, Ren

This research work presents the design, theoretical analysis, fabrication, interface electronics, and experimental results of a Silicon-On-Insulator (SOI) based Multiple-Beam Tuning-Fork Gyroscope (MB-TFG). Based on a numerical model of Thermo-Elastic Damping (TED), a Multiple-Beam Tuning-Fork Structure (MB-TFS) is designed with high Quality factors (Qs) in its two operation modes. A comprehensive theoretical analysis of the MB-TFG design is conducted to relate the design parameters to its operation parameters and further performance parameters. In conjunction with a mask that defines the device through trenches to alleviate severe fabrication effect on anchor loss, a simple one-mask fabrication process is employed to implement this MB-TFG design on SOI wafers. The fabricated MB-TFGs are tested with PCB-level interface electronics and a thorough comparison between the experimental results and a theoretical analysis is conducted to verify the MB-TFG design and accurately interpret the measured performance. The highest measured Qs of the fabricated MB-TFGs in vacuum are 255,000 in the drive-mode and 103,000 in the sense-mode, at a frequency of 15.7kHz. Under a frequency difference of 4Hz between the two modes (operation frequency is 16.8kHz) and a drive-mode vibration amplitude of 3.0um, the measured rate sensitivity is 80mVpp/°/s with an equivalent impedance of 6MQ. The calculated overall rate resolution of this device is 0.37/hrhiElz, while the measured Angle Random Walk (ARW) and bias instability are 6.67°/'vhr and 95°/hr, respectively.

Steering of quantum waves: Demonstration of Y-junction transistors using InAs quantum wires

NASA Astrophysics Data System (ADS)

Jones, Gregory M.; Qin, Jie; Yang, Chia-Hung; Yang, Ming-Jey

2005-06-01

In this paper we demonstrate using an InAs quantum wire Y-branch switch that the electron wave can be switched to exit from the two drains by a lateral gate bias. The gating modifies the electron wave functions as well as their interference pattern, causing the anti-correlated, oscillatory transconductances. Our result suggests a new transistor function in a multiple-lead ballistic quantum wire system.

M-plane core-shell InGaN/GaN multiple-quantum-wells on GaN wires for electroluminescent devices.

PubMed

Koester, Robert; Hwang, Jun-Seok; Salomon, Damien; Chen, Xiaojun; Bougerol, Catherine; Barnes, Jean-Paul; Dang, Daniel Le Si; Rigutti, Lorenzo; de Luna Bugallo, Andres; Jacopin, Gwénolé; Tchernycheva, Maria; Durand, Christophe; Eymery, Joël

2011-11-09

Nonpolar InGaN/GaN multiple quantum wells (MQWs) grown on the {11-00} sidewalls of c-axis GaN wires have been grown by organometallic vapor phase epitaxy on c-sapphire substrates. The structural properties of single wires are studied in detail by scanning transmission electron microscopy and in a more original way by secondary ion mass spectroscopy to quantify defects, thickness (1-8 nm) and In-composition in the wells (∼16%). The core-shell MQW light emission characteristics (390-420 nm at 5 K) were investigated by cathodo- and photoluminescence demonstrating the absence of the quantum Stark effect as expected due to the nonpolar orientation. Finally, these radial nonpolar quantum wells were used in room-temperature single-wire electroluminescent devices emitting at 392 nm by exploiting sidewall emission.

Quantum-Well Thermophotovoltaic Cells

NASA Technical Reports Server (NTRS)

Freudlich, Alex; Ignatiev, Alex

2009-01-01

Thermophotovoltaic cells containing multiple quantum wells have been invented as improved means of conversion of thermal to electrical energy. The semiconductor bandgaps of the quantum wells can be tailored to be narrower than those of prior thermophotovoltaic cells, thereby enabling the cells to convert energy from longer-wavelength photons that dominate the infrared-rich spectra of typical thermal sources with which these cells would be used. Moreover, in comparison with a conventional single-junction thermophotovoltaic cell, a cell containing multiple narrow-bandgap quantum wells according to the invention can convert energy from a wider range of wavelengths. Hence, the invention increases the achievable thermal-to-electrical energy-conversion efficiency. These thermophotovoltaic cells are expected to be especially useful for extracting electrical energy from combustion, waste-heat, and nuclear sources having temperatures in the approximate range from 1,000 to 1,500 C.

2.8 {mu}m emission from type-I quantum wells grown on InAs{sub x}P{sub 1-x}/InP metamorphic graded buffers

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

Jung, Daehwan; Song, Yuncheng; Larry Lee, Minjoo

We report 2.8 {mu}m emission from compressively strained type-I quantum wells (QWs) grown on InP-based metamorphic InAs{sub x}P{sub 1-x} step-graded buffers. High quality metamorphic graded buffers showed smooth surface morphology and low threading dislocation densities of approximately 2.5 Multiplication-Sign 10{sup 6} cm{sup -2}. High-resolution x-ray diffraction scans showed strong satellites from multiple quantum wells grown on metamorphic buffers, and cross-sectional transmission electron microscopy revealed smooth and coherent quantum well interfaces. Room-temperature photoluminescence emission at 2.8 {mu}m with a narrow linewidth ({approx}50 meV) shows the promise of metamorphic growth for mid-infrared laser diodes on InP.

Thick-shell nanocrystal quantum dots

DOEpatents

Hollingsworth, Jennifer A [Los Alamos, NM; Chen, Yongfen [Eugene, OR; Klimov, Victor I [Los Alamos, NM; Htoon, Han [Los Alamos, NM; Vela, Javier [Los Alamos, NM

2011-05-03

Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

Quantum light in coupled interferometers for quantum gravity tests.

PubMed

Ruo Berchera, I; Degiovanni, I P; Olivares, S; Genovese, M

2013-05-24

In recent years quantum correlations have received a lot of attention as a key ingredient in advanced quantum metrology protocols. In this Letter we show that they provide even larger advantages when considering multiple-interferometer setups. In particular, we demonstrate that the use of quantum correlated light beams in coupled interferometers leads to substantial advantages with respect to classical light, up to a noise-free scenario for the ideal lossless case. On the one hand, our results prompt the possibility of testing quantum gravity in experimental configurations affordable in current quantum optics laboratories and strongly improve the precision in "larger size experiments" such as the Fermilab holometer; on the other hand, they pave the way for future applications to high precision measurements and quantum metrology.

Triple-Quantum Filtered NMR Imaging of Sodium -23 in the Human Brain

NASA Astrophysics Data System (ADS)

Keltner, John Robinson

In the past multiple-quantum filtered imaging of biexponential relaxation sodium-23 nuclei in the human brain has been limited by low signal to noise ratios; this thesis demonstrates that such imaging is feasible when using a modified gradient-selected triple-quantum filter at a repetition time which maximizes the signal to noise ratio. Nuclear magnetic resonance imaging of biexponential relaxation sodium-23 (^{23}Na) nuclei in the human brain may be useful for detecting ischemia, cancer, and pathophysiology related to manic-depression. Multiple -quantum filters may be used to selectively image biexponential relaxation ^{23}Na signals since these filters suppress single-exponential relaxation ^{23}Na signals. In this thesis, the typical repetition times (200 -300 ms) used for in vivo multiple-quantum filtered ^{23}Na experiments are shown to be approximately 5 times greater than the optimal repetition time which maximizes multiple-quantum filtered SNR. Calculations and experimental verification show that the gradient-selected triple-quantum (GS3Q) filtered SNR for ^ {23}Na in a 4% agarose gel increases by a factor of two as the repetition time decreases from 300 ms to 55 ms. It is observed that a simple reduction of repetition time also increases spurious single-quantum signals from GS3Q filtered experiments. Irreducible superoperator calculations have been used to design a modified GS3Q filter which more effectively suppresses the spurious single-quantum signals. The modified GS3Q filter includes a preparatory crusher gradient and two-step-phase cycling. Using the modified GS3Q filter and a repetition time of 70 ms, a three dimensional triple-quantum filtered image of a phantom modelling ^{23} Na in the brain was obtained. The phantom consisted of two 4 cm diameter spheres inside of a 8.5 cm x 7 cm ellipsoid. The two spheres contained 0.012 and 0.024 M ^{23}Na in 4% agarose gel. Surrounding the spheres and inside the ellipsoid was 0.03 M aqueous ^{23}Na. The image dimensions were 16 x 16 x 16 voxels with the dimension of a voxel being 1.5 x 1.5 x 1.5 cm^3. The signal to noise ratio for the GS3Q filtered ^ {23}Na signal from the 0.012 and 0.024 M ^{23}Na spheres was 17 and 30 for a 54 minute experiment at 2.35 T. (Abstract shortened by UMI.).

High-fidelity gates towards a scalable superconducting quantum processor

NASA Astrophysics Data System (ADS)

Chow, Jerry M.; Corcoles, Antonio D.; Gambetta, Jay M.; Rigetti, Chad; Johnson, Blake R.; Smolin, John A.; Merkel, Seth; Poletto, Stefano; Rozen, Jim; Rothwell, Mary Beth; Keefe, George A.; Ketchen, Mark B.; Steffen, Matthias

2012-02-01

We experimentally explore the implementation of high-fidelity gates on multiple superconducting qubits coupled to multiple resonators. Having demonstrated all-microwave single and two qubit gates with fidelities > 90% on multi-qubit single-resonator systems, we expand the application to qubits across two resonators and investigate qubit coupling in this circuit. The coupled qubit-resonators are building blocks towards two-dimensional lattice networks for the application of surface code quantum error correction algorithms.

In vivo single-shot three-dimensionally localized multiple quantum spectroscopy of GABA in the human brain with improved spectral selectivity

NASA Astrophysics Data System (ADS)

Choi, In-Young; Lee, Sang-Pil; Shen, Jun

2005-01-01

A single-shot multiple quantum filtering method is developed that uses two double-band frequency selective pulses for enhanced spectral selectivity in combination with a slice-selective 90°, a slice-selective universal rotator 90°, and a spectral-spatial pulse composed of two slice-selective universal rotator 45° pulses for single-shot three-dimensional localization. The use of this selective multiple quantum filtering method for C3 and C4 methylene protons of GABA resulted in improved spectral selectivity for GABA and effective suppression of overlapping signals such as creatine and glutathione in each single scan, providing reliable measurements of the GABA doublet in all subjects. The concentration of GABA was measured to be 0.7 ± 0.2 μmol/g (means ± SD, n = 15) in the fronto-parietal region of the human brain in vivo.

Direct evaluation of boson dynamics via finite-temperature time-dependent variation with multiple Davydov states.

PubMed

Fujihashi, Yuta; Wang, Lu; Zhao, Yang

2017-12-21

Recent advances in quantum optics allow for exploration of boson dynamics in dissipative many-body systems. However, the traditional descriptions of quantum dissipation using reduced density matrices are unable to capture explicit information of bath dynamics. In this work, efficient evaluation of boson dynamics is demonstrated by combining the multiple Davydov Ansatz with finite-temperature time-dependent variation, going beyond what state-of-the-art density matrix approaches are capable to offer for coupled electron-boson systems. To this end, applications are made to excitation energy transfer in photosynthetic systems, singlet fission in organic thin films, and circuit quantum electrodynamics in superconducting devices. Thanks to the multiple Davydov Ansatz, our analysis of boson dynamics leads to clear revelation of boson modes strongly coupled to electronic states, as well as in-depth description of polaron creation and destruction in the presence of thermal fluctuations.

Theoretical study of polarization insensitivity of carrier-induced refractive index change of multiple quantum well.

PubMed

Miao, Qingyuan; Zhou, Qunjie; Cui, Jun; He, Ping-An; Huang, Dexiu

2014-12-29

Characteristics of polarization insensitivity of carrier-induced refractive index change of 1.55 μm tensile-strained multiple quantum well (MQW) are theoretically investigated. A comprehensive MQW model is proposed to effectively extend the application range of previous models. The model considers the temperature variation as well as the nonuniform distribution of injected carrier in MQW. Tensile-strained MQW is expected to achieve polarization insensitivity of carrier-induced refractive index change over a wide wavelength range as temperature varies from 0°C to 40°C, while the magnitude of refractive index change keeps a large value (more than 3 × 10^-3). And that the polarization insensitivity of refractive index change can maintain for a wide range of carrier concentration. Multiple quantum well with different material and structure parameters is anticipated to have the similar polarization insensitivity of refractive index change, which shows the design flexibility.

Memory-assisted quantum key distribution resilient against multiple-excitation effects

NASA Astrophysics Data System (ADS)

Lo Piparo, Nicolò; Sinclair, Neil; Razavi, Mohsen

2018-01-01

Memory-assisted measurement-device-independent quantum key distribution (MA-MDI-QKD) has recently been proposed as a technique to improve the rate-versus-distance behavior of QKD systems by using existing, or nearly-achievable, quantum technologies. The promise is that MA-MDI-QKD would require less demanding quantum memories than the ones needed for probabilistic quantum repeaters. Nevertheless, early investigations suggest that, in order to beat the conventional memory-less QKD schemes, the quantum memories used in the MA-MDI-QKD protocols must have high bandwidth-storage products and short interaction times. Among different types of quantum memories, ensemble-based memories offer some of the required specifications, but they typically suffer from multiple excitation effects. To avoid the latter issue, in this paper, we propose two new variants of MA-MDI-QKD both relying on single-photon sources for entangling purposes. One is based on known techniques for entanglement distribution in quantum repeaters. This scheme turns out to offer no advantage even if one uses ideal single-photon sources. By finding the root cause of the problem, we then propose another setup, which can outperform single memory-less setups even if we allow for some imperfections in our single-photon sources. For such a scheme, we compare the key rate for different types of ensemble-based memories and show that certain classes of atomic ensembles can improve the rate-versus-distance behavior.

Multidimensional Aptitude Battery-Second Edition Intelligence Testing of Remotely Piloted Aircraft Training Candidates Compared with Manned Airframe Training Candidates

DTIC Science & Technology

2015-03-01

assessing the general intelligence and neuropsychological aptitudes of USAF RPA pilot training candidates. Chappelle et al. obtained comprehensive...computer-based intelligence testing (Multidimensional Aptitude Battery-Second Edition [MAB-II]) and neuropsychological screening (MicroCog) on USAF MQ-1... schizophrenia , attention deficit hyperactivity disorder, and autism spectrum disorders) and not on very high functioning populations such as aviators

War in the Caucasus is Inevitable

DTIC Science & Technology

2011-06-16

develop a Pan-Turkish state and eliminate internal threats. The Young Turks considered Armenians as a threat to their regime. In 1914, at the...the cars, the music , the storms, the flooding, head wounds, respiratory problems, hospital runs, bicycles, finances, making friends and country... music awards are all what have made Norfolk an unforgettable experience for all of us. KT, ZD and MQ, I couldn’t have done this without you

HOW THE MILITARY CAN INTEGRATE UNMANNED AERIAL SYSTEMS IN THE CIVIL RESERVE AIR FLEET

DTIC Science & Technology

2016-10-01

brings new capabilities and continues to fundamentally impact military doctrine and strategy, particularly in how civilian operators or contractors ...missions has stretched military personnel and resources thin. General Atomics, a California-based defense contractor , produces the highly successful MQ-1...and a large number of support personnel required to operate UAS missions. An already established civilian contractor presence AU/ACSC/2016 5

Recycled water sources influence the bioavailability of copper to earthworms.

PubMed

Kunhikrishnan, Anitha; Bolan, Nanthi S; Naidu, Ravi; Kim, Won-Il

2013-10-15

Re-use of wastewaters can overcome shortfalls in irrigation demand and mitigate environmental pollution. However, in an untreated or partially treated state, these water sources can introduce inorganic contaminants, including heavy metals, to soils that are irrigated. In this study, earthworms (Eisenia fetida) have been used to determine copper (Cu) bioavailability in two contrasting soils irrigated with farm dairy, piggery and winery effluents. Soils spiked with varying levels of Cu (0-1,000 mg/kg) were subsequently irrigated with recycled waters and Milli-Q (MQ) water and Cu bioavailability to earthworms determined by mortality and avoidance tests. Earthworms clearly avoided high Cu soils and the effect was more pronounced in the absence than presence of recycled water irrigation. At the highest Cu concentration (1,000 mg/kg), worm mortality was 100% when irrigated with MQ-water; however, when irrigated with recycled waters, mortality decreased by 30%. Accumulation of Cu in earthworms was significantly less in the presence of recycled water and was dependent on CaCl2-extractable free Cu(2+) concentration in the soil. Here, it is evident that organic carbon in recycled waters was effective in decreasing the toxic effects of Cu on earthworms, indicating that the metal-organic complexes decreased Cu bioavailability to earthworms. Copyright © 2012 Elsevier B.V. All rights reserved.

The Prodiguer Messaging Platform

NASA Astrophysics Data System (ADS)

Greenslade, Mark; Denvil, Sebastien; Raciazek, Jerome; Carenton, Nicolas; Levavasseur, Guillame

2014-05-01

CONVERGENCE is a French multi-partner national project designed to gather HPC and informatics expertise to innovate in the context of running French climate models with differing grids and at differing resolutions. Efficient and reliable execution of these models and the management and dissemination of model output (data and meta-data) are just some of the complexities that CONVERGENCE aims to resolve. The Institut Pierre Simon Laplace (IPSL) is responsible for running climate simulations upon a set of heterogenous HPC environments within France. With heterogeneity comes added complexity in terms of simulation instrumentation and control. Obtaining a global perspective upon the state of all simulations running upon all HPC environments has hitherto been problematic. In this presentation we detail how, within the context of CONVERGENCE, the implementation of the Prodiguer messaging platform resolves complexity and permits the development of real-time applications such as: 1. a simulation monitoring dashboard; 2. a simulation metrics visualizer; 3. an automated simulation runtime notifier; 4. an automated output data & meta-data publishing pipeline; The Prodiguer messaging platform leverages a widely used open source message broker software called RabbitMQ. RabbitMQ itself implements the Advanced Message Queue Protocol (AMPQ). Hence it will be demonstrated that the Prodiguer messaging platform is built upon both open source and open standards.

Fragment molecular orbital study on electron tunneling mechanisms in bacterial photosynthetic reaction center.

PubMed

Kitoh-Nishioka, Hirotaka; Ando, Koji

2012-11-01

The tunneling mechanisms of electron transfers (ETs) in photosynthetic reaction center of Blastochloris viridis are studied by the ab initio fragment molecular orbital (FMO) method combined with the generalized Mulliken-Hush (GMH) and the bridge Green function (GF) calculations of the electronic coupling T(DA) and the tunneling current method for the ET pathway analysis at the fragment-based resolution. For the ET from batctriopheophytin (H(L)) to menaquinone (MQ), a major tunneling current through Trp M250 and a minor back flow via Ala M215, Ala M216, and His M217 are quantified. For the ET from MQ to ubiquinone, the major tunneling pathway via the nonheme Fe(2+) and His L190 is identified as well as minor pathway via His M217 and small back flows involving His L230, Glu M232, and His M264. At the given molecular structure from X-ray experiment, the spin state of the Fe(2+) ion, its replacement by Zn(2+), or its removal are found to affect the T(DA) value by factors within 2.2. The calculated T(DA) values, together with experimentally estimated values of the driving force and the reorganization energy, give the ET rates in reasonable agreement with experiments.

Role of redox signaling in the autonomous proliferative response of endothelial cells to hypoxia.

PubMed

Schäfer, M; Schäfer, C; Ewald, N; Piper, H M; Noll, Th

2003-05-16

Endothelial cells exhibit an autonomous proliferative response to hypoxia, independent of paracrine effectors. In cultured endothelial cells of porcine aorta, we analyzed the signaling of this response, with a focus on the roles of redox signaling and the MEK/ERK pathway. Transient hypoxia (1 hour) stimulated proliferation by 61+/-4% (n=16; P<0.05 versus control), quantified after 24 hours normoxic postincubation. Hypoxia induced an activation of ERK2 and of NAD(P)H oxidase and a burst of reactive oxygen species (ROS), determined by DCF fluorescence. To inhibit the MEK/ERK pathway, we used PD 98059 (PD, 20 micromol/L); to downregulate NAD(P)H oxidase, we applied p22phox antisense oligonucleotides; and to inhibit mitochondrial ROS generation, we used the ubiquinone derivate mitoQ (MQ, 10 micromol/L). All three inhibitions suppressed the proliferative response: PD inhibited NAD(P)H oxidase activation; p22phox antisense transfection did not inhibit ERK2 activation, but suppressed ROS production; and MQ inhibited ERK2 activation and ROS production. The autonomous proliferative response depends on the MEK/ERK pathway and redox signaling steps upstream and downstream of ERK. Located upstream is ROS generation by mitochondria, downstream is NAD(P)H oxidase.

Controllably releasing long-lived quantum memory for photonic polarization qubit into multiple spatially-separate photonic channels

PubMed Central

Chen, Lirong; Xu, Zhongxiao; Zeng, Weiqing; Wen, Yafei; Li, Shujing; Wang, Hai

2016-01-01

We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple spatially-separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel. By changing the propagating directions of the read laser beam, we controllably release the retrieved PPQs into 7 different photonic output channels, respectively. At a storage time of δt = 5 μs, the least quantum-process fidelity in 7 different output channels is ~89%. At one of the output channels, the measured maximum quantum-process fidelity for the PPQs is 94.2% at storage time of δt = 0.85 ms. At storage time of 6 ms, the quantum-process fidelity is still beyond the bound of 78% to violate the Bell’s inequality. The demonstrated controllable release of the stored PPQs may extend the capabilities of the quantum information storage technique. PMID:27667262

Modeling techniques for quantum cascade lasers

NASA Astrophysics Data System (ADS)

Jirauschek, Christian; Kubis, Tillmann

2014-03-01

Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband transitions between quantized states in specifically designed multiple-quantum-well heterostructures. A systematic improvement of quantum cascade lasers with respect to operating temperature, efficiency, and spectral range requires detailed modeling of the underlying physical processes in these structures. Moreover, the quantum cascade laser constitutes a versatile model device for the development and improvement of simulation techniques in nano- and optoelectronics. This review provides a comprehensive survey and discussion of the modeling techniques used for the simulation of quantum cascade lasers. The main focus is on the modeling of carrier transport in the nanostructured gain medium, while the simulation of the optical cavity is covered at a more basic level. Specifically, the transfer matrix and finite difference methods for solving the one-dimensional Schrödinger equation and Schrödinger-Poisson system are discussed, providing the quantized states in the multiple-quantum-well active region. The modeling of the optical cavity is covered with a focus on basic waveguide resonator structures. Furthermore, various carrier transport simulation methods are discussed, ranging from basic empirical approaches to advanced self-consistent techniques. The methods include empirical rate equation and related Maxwell-Bloch equation approaches, self-consistent rate equation and ensemble Monte Carlo methods, as well as quantum transport approaches, in particular the density matrix and non-equilibrium Green's function formalism. The derived scattering rates and self-energies are generally valid for n-type devices based on one-dimensional quantum confinement, such as quantum well structures.

Modeling techniques for quantum cascade lasers

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

Jirauschek, Christian; Kubis, Tillmann

2014-03-15

Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband transitions between quantized states in specifically designed multiple-quantum-well heterostructures. A systematic improvement of quantum cascade lasers with respect to operating temperature, efficiency, and spectral range requires detailed modeling of the underlying physical processes in these structures. Moreover, the quantum cascade laser constitutes a versatile model device for the development and improvement of simulation techniques in nano- and optoelectronics. This review provides a comprehensive survey and discussion of the modeling techniques used for the simulation ofmore » quantum cascade lasers. The main focus is on the modeling of carrier transport in the nanostructured gain medium, while the simulation of the optical cavity is covered at a more basic level. Specifically, the transfer matrix and finite difference methods for solving the one-dimensional Schrödinger equation and Schrödinger-Poisson system are discussed, providing the quantized states in the multiple-quantum-well active region. The modeling of the optical cavity is covered with a focus on basic waveguide resonator structures. Furthermore, various carrier transport simulation methods are discussed, ranging from basic empirical approaches to advanced self-consistent techniques. The methods include empirical rate equation and related Maxwell-Bloch equation approaches, self-consistent rate equation and ensemble Monte Carlo methods, as well as quantum transport approaches, in particular the density matrix and non-equilibrium Green's function formalism. The derived scattering rates and self-energies are generally valid for n-type devices based on one-dimensional quantum confinement, such as quantum well structures.« less

Optically controlled reflection modulator using GaAs-AlGaAs n-i-p-i/multiple-quantum-well structures

NASA Technical Reports Server (NTRS)

Law, K.-K.; Simes, R. J.; Coldren, L. A.; Gossard, A. C.; Maserjian, J.

1989-01-01

An optically controlled reflection modulator has been demonstrated that consists of a combination of a GaAs-AlGaAs n-i-p-i doping structure with a multiple-quantum-well structures on top of a distributed Bragg reflector, all grown by MBE. A modulation of approximately 60 percent is obtained on the test structure, corresponding to a differential change of absorption coefficient in the quantum wells of approximately 7500/cm. Changes in reflectance can be observed with a control beam power as low as 1.5 microW. This device structure has the potential of being developed as an optically addressed spatial light modulator for optical information processing.

Effect of hexagonal hillock on luminescence characteristic of multiple quantum wells structure

NASA Astrophysics Data System (ADS)

Du, Jinjuan; Xu, Shengrui; Li, Peixian; Zhang, Jincheng; Zhao, Ying; Peng, Ruoshi; Fan, Xiaomeng; Hao, Yue

2018-04-01

GaN based ultraviolet multiple quantum well structures grown on a c-plane sapphire substrate by metal organic chemical deposition showed a microstructure with a large amount of huge hexagonal hillocks. The polarity of the sample is confirmed by etching with sodium hydroxide solution. The luminous intensity distribution of a typical hexagonal hillock was investigated by the phototluminescent mapping and the luminous intensity at hillock top regions was found to be 15 times higher than that of the regions around hillocks. The reduction of dislocations, the decreasing of the quantum confirmed stack effect caused by semipolar plane and the inclination of the sidewalls of the hexagonal hillock were responsible for the enhancement of luminous intensity.

Performance analysis of GeSn-alloy-based multiple quantum well transistor laser

NASA Astrophysics Data System (ADS)

Ranjan, Ravi; Pareek, Prakash; Anwer Askari, Syed Sadique; Das, Mukul K.

2018-02-01

The Group IV Photonics (GFP) which include an alloy of Si, Ge & Sn that gives a direct bandgap material (GeSn, SiGeSn) in near and mid-IR region used as an active material in photonics devices. The multiple quantum well SiGeSn/GeSn transistor laser structure is considered in this paper and performance parameters are evaluated for the same. The result shows that the threshold base current density (2.6 kA/cm2) for the proposed device initially decreases with increasing number of quantum well (QW) and later on it saturates. The current gain and output photon density of the device decreases and increases respectively, with increasing number of QW.

Resonance fluorescence trajectories in superconducting qubit

NASA Astrophysics Data System (ADS)

Naghiloo, Mahdi; Tan, Dian; Harrington, Patrick; Lewalle, Philippe; Jordan, Andrew; Murch, Kater

We employ phase-sensitive amplification to perform homodyne detection of the resonance fluorescence from a driven superconducting artificial atom. Entanglement between the emitter and its fluorescence allows us to track the individual quantum state trajectories of the emitter. We analyze the ensemble properties of these trajectories by considering paths that connect specific initial and final states. By applying a stochastic path integral formalism, we calculate equations of motion for the most likely path between two quantum states and compare these predicted paths to experimental data. Drawing on the mathematical similarity between the action formalism of the most likely quantum paths and ray optics, we study the emergence of caustics in quantum trajectories-situations where multiple extrema in the stochastic action occur. We observe such multiple most likely paths in experimental data and find these paths to be in reasonable quantitative agreement with theoretical calculations. Supported by the John Templeton Foundation.

Multiple exciton generation for photoelectrochemical hydrogen evolution reactions with quantum yields exceeding 100%

DOE PAGES

Yan, Yong; Crisp, Ryan W.; Gu, Jing; ...

2017-04-03

Multiple exciton generation (MEG) in quantum dots (QDs) has the potential to greatly increase the power conversion efficiency in solar cells and in solar-fuel production. During the MEG process, two electron-hole pairs (excitons) are created from the absorption of one high-energy photon, bypassing hot-carrier cooling via phonon emission. Here we demonstrate that extra carriers produced via MEG can be used to drive a chemical reaction with quantum efficiency above 100%. We developed a lead sulfide (PbS) QD photoelectrochemical cell that is able to drive hydrogen evolution from aqueous Na 2S solution with a peak external quantum efficiency exceeding 100%. QDmore » photoelectrodes that were measured all demonstrated MEG when the incident photon energy was larger than 2.7 times the bandgap energy. Finally, our results demonstrate a new direction in exploring high-efficiency approaches to solar fuels.« less

A multiple-scattering polaritonic-operator method for hybrid arrays of metal nanoparticles and quantum emitters

NASA Astrophysics Data System (ADS)

Chatzidakis, Georgios D.; Yannopapas, Vassilios

2018-05-01

We present a new technique for the study of hybrid collections of quantum emitters (atoms, molecules, quantum dots) with nanoparticles. The technique is based on a multiple-scattering polaritonic-operator formalism in conjunction with an electromagnetic coupled dipole method. Apart from collections of quantum emitters and nanoparticles, the method can equally treat the interaction of a collection of quantum emitters with a single nano-object of arbitrary shape in which case the nano-object is treated as a finite three-dimensional lattice of point scatterers. We have applied our method to the case of linear array (chain) of dimers of quantum emitters and metallic nanoparticles wherein the corresponding (geometrical and physical) parameters of the dimers are chosen so as the interaction between the emitter and the nanoparticle lies in the strong-coupling regime in order to enable the formation of plexciton states in the dimer. In particular, for a linear chain of dimers, we show that the corresponding light spectra reveal a multitude of plexciton modes resulting from the hybridization of the plexciton resonances of each individual dimer in a manner similar to the tight-binding description of electrons in solids.

Quantum Feynman Ratchet

NASA Astrophysics Data System (ADS)

Goyal, Ketan; Kawai, Ryoichi

As nanotechnology advances, understanding of the thermodynamic properties of small systems becomes increasingly important. Such systems are found throughout physics, biology, and chemistry manifesting striking properties that are a direct result of their small dimensions where fluctuations become predominant. The standard theory of thermodynamics for macroscopic systems is powerless for such ever fluctuating systems. Furthermore, as small systems are inherently quantum mechanical, influence of quantum effects such as discreteness and quantum entanglement on their thermodynamic properties is of great interest. In particular, the quantum fluctuations due to quantum uncertainty principles may play a significant role. In this talk, we investigate thermodynamic properties of an autonomous quantum heat engine, resembling a quantum version of the Feynman Ratchet, in non-equilibrium condition based on the theory of open quantum systems. The heat engine consists of multiple subsystems individually contacted to different thermal environments.

Towards a Quantum Memory assisted MDI-QKD node

NASA Astrophysics Data System (ADS)

Namazi, Mehdi; Vallone, Giuseppe; Jordaan, Bertus; Goham, Connor; Shahrokhshahi, Reihaneh; Villoresi, Paolo; Figueroa, Eden

2017-04-01

The creation of large quantum network that permits the communication of quantum states and the secure distribution of cryptographic keys requires multiple operational quantum memories. In this work we present our progress towards building a prototypical quantum network that performs the memory-assisted measurement device independent QKD protocol. Currently our network combines the quantum part of the BB84 protocol with room-temperature quantum memory operation, while still maintaining relevant quantum bit error rates for single-photon level operation. We will also discuss our efforts to use a network of two room temperature quantum memories, receiving, storing and transforming randomly polarized photons in order to realize Bell state measurements. The work was supported by the US-Navy Office of Naval Research, Grant Number N00141410801, the National Science Foundation, Grant Number PHY-1404398 and the Simons Foundation, Grant Number SBF241180.

Joining the quantum state of two photons into one

NASA Astrophysics Data System (ADS)

Vitelli, Chiara; Spagnolo, Nicolò; Aparo, Lorenzo; Sciarrino, Fabio; Santamato, Enrico; Marrucci, Lorenzo

2013-07-01

Photons are the ideal carriers of quantum information for communication. Each photon can have a single or multiple qubits encoded in its internal quantum state, as defined by optical degrees of freedom such as polarization, wavelength, transverse modes and so on. However, as photons do not interact, multiplexing and demultiplexing the quantum information across photons has not been possible hitherto. Here, we introduce and demonstrate experimentally a physical process, named `quantum joining', in which the two-dimensional quantum states (qubits) of two input photons are combined into a single output photon, within a four-dimensional Hilbert space. The inverse process is also proposed, in which the four-dimensional quantum state of a single photon is split into two photons, each carrying a qubit. Both processes can be iterated, and hence provide a flexible quantum interconnect to bridge multiparticle protocols of quantum information with multidegree-of-freedom ones, with possible applications in future quantum networking.

Origins and optimization of entanglement in plasmonically coupled quantum dots

DOE PAGES

Otten, Matthew; Larson, Jeffrey; Min, Misun; ...

2016-08-11

In this paper, a system of two or more quantum dots interacting with a dissipative plasmonic nanostructure is investigated in detail by using a cavity quantum electrodynamics approach with a model Hamiltonian. We focus on determining and understanding system configurations that generate multiple bipartite quantum entanglements between the occupation states of the quantum dots. These configurations include allowing for the quantum dots to be asymmetrically coupled to the plasmonic system. Analytical solution of a simplified limit for an arbitrary number of quantum dots and numerical simulations and optimization for the two- and three-dot cases are used to develop guidelines formore » maximizing the bipartite entanglements. For any number of quantum dots, we show that through simple starting states and parameter guidelines, one quantum dot can be made to share a strong amount of bipartite entanglement with all other quantum dots in the system, while entangling all other pairs to a lesser degree.« less

Entropic Uncertainty Relation and Information Exclusion Relation for multiple measurements in the presence of quantum memory

NASA Astrophysics Data System (ADS)

Zhang, Jun; Zhang, Yang; Yu, Chang-Shui

2015-06-01

The Heisenberg uncertainty principle shows that no one can specify the values of the non-commuting canonically conjugated variables simultaneously. However, the uncertainty relation is usually applied to two incompatible measurements. We present tighter bounds on both entropic uncertainty relation and information exclusion relation for multiple measurements in the presence of quantum memory. As applications, three incompatible measurements on Werner state and Horodecki’s bound entangled state are investigated in details.

Corrigendum to "Multiple-quantum spin counting in magic-angle-spinning NMR via low-power symmetry-based dipolar recoupling" [J. Magn. Reson. 236 (2013) 31-40

NASA Astrophysics Data System (ADS)

Teymoori, Gholamhasan; Pahari, Bholanath; Viswanathan, Elumalai; Edén, Mattias

2017-03-01

The authors regret that an inappropriate NMR data processing, not known to all authors at the time of publication, was used to produce the multiple-quantum coherence (MQC) spin counting data presented in our article: this lead to artificially enhanced results, particularly concerning those obtained at long MQC excitation intervals (τexc). Here we reproduce Figs. 4-7 with correctly processed data.

An analytical derivation of MC-SCF vibrational wave functions for the quantum dynamical simulation of multiple proton transfer reactions: Initial application to protonated water chains

NASA Astrophysics Data System (ADS)

Drukker, Karen; Hammes-Schiffer, Sharon

1997-07-01

This paper presents an analytical derivation of a multiconfigurational self-consistent-field (MC-SCF) solution of the time-independent Schrödinger equation for nuclear motion (i.e. vibrational modes). This variational MC-SCF method is designed for the mixed quantum/classical molecular dynamics simulation of multiple proton transfer reactions, where the transferring protons are treated quantum mechanically while the remaining degrees of freedom are treated classically. This paper presents a proof that the Hellmann-Feynman forces on the classical degrees of freedom are identical to the exact forces (i.e. the Pulay corrections vanish) when this MC-SCF method is used with an appropriate choice of basis functions. This new MC-SCF method is applied to multiple proton transfer in a protonated chain of three hydrogen-bonded water molecules. The ground state and the first three excited state energies and the ground state forces agree well with full configuration interaction calculations. Sample trajectories are obtained using adiabatic molecular dynamics methods, and nonadiabatic effects are found to be insignificant for these sample trajectories. The accuracy of the excited states will enable this MC-SCF method to be used in conjunction with nonadiabatic molecular dynamics methods. This application differs from previous work in that it is a real-time quantum dynamical nonequilibrium simulation of multiple proton transfer in a chain of water molecules.

Colloidal 2D nanosheets of MoS2 and other transition metal dichalcogenides through liquid-phase exfoliation.

PubMed

Grayfer, Ekaterina D; Kozlova, Mariia N; Fedorov, Vladimir E

2017-07-01

This review focuses on the exfoliation of transition metal dichalcogenides MQ 2 (TMD, M=Mo, W, etc., Q=S, Se, Te) in liquid media, leading to the formation of 2D nanosheets dispersed in colloids. Nowadays, colloidal dispersions of MoS 2 , MoSe 2 , WS 2 and other related materials are considered for a wide range of applications, including electronic and optoelectronic devices, energy storage and conversion, sensors for gases, catalysts and catalyst supports, biomedicine, etc. We address various methods developed so far for transferring these materials from bulk to nanoscale thickness, and discuss their stabilization and factors influencing it. Long-time known exfoliation through Li intercalation has received renewed attention in recent years, and is recognized as a method yielding highest dispersed concentrations of single-layer MoS 2 and related materials. Latest trends in the intercalation/exfoliation approach include electrochemical lithium intercalation, experimenting with various intercalating agents, multi-step intercalation, etc. On the other hand, direct sonication in solvents is a much simpler technique that allows one to avoid dangerous reagents, long reaction times and purifying steps. The influence of the solvent characteristics on the colloid formation was closely investigated in numerous recent studies. Moreover, it is being recognized that, besides solvent properties, sonication parameters and solvent transformations may affect the process in a crucial way. The latest data on the interaction of MoS 2 with solvents evidence that not only solution thermodynamics should be employed to understand the formation and stabilization of such colloids, but also general and organic chemistry. It appears that due to the sonolysis of the solvents and cutting of the MoS 2 layers in various directions, the reactive edges of the colloidal nanosheets may bear various functionalities, which participate in their stabilization in the colloidal state. In most cases, direct exfoliation of MQ 2 into colloidal nanosheets is conducted in organic solvents, while a small amount of works report low-concentrated colloids in pure water. To improve the dispersion abilities of transition metal dichalcogenides in water, various stabilizers are often introduced into the reaction media, and their interactions with nanosheets play an important role in the stabilization of the dispersions. Surfactants, polymers and biomolecules usually interact with transition metal dichalcogenide nanosheets through non-covalent mechanisms, similarly to the cases of graphene and carbon nanotubes. Finally, we survey covalent chemical modification of colloidal MQ 2 nanosheets, a special and different approach, consisting in the functionalization of MQ 2 surfaces with help of thiol chemistry, interaction with electrophiles, or formation of inorganic coordination complexes. The intentional design of surface chemistry of the nanosheets is a very promising way to control their solubility, compatibility with other moieties and incorporation into hybrid structures. Although the scope of the present review is limited to transition metal dichalcogenides, the dispersion in colloids of other chalcogenides (such as NbS 3 , VS 4 , Mo 2 S 3 , etc.) in many ways follows similar trends. We conclude the review by discussing current challenges in the area of exfoliation of MoS 2 and its related materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Adiabatic Quantum Computation: Coherent Control Back Action.

PubMed

Goswami, Debabrata

2006-11-22

Though attractive from scalability aspects, optical approaches to quantum computing are highly prone to decoherence and rapid population loss due to nonradiative processes such as vibrational redistribution. We show that such effects can be reduced by adiabatic coherent control, in which quantum interference between multiple excitation pathways is used to cancel coupling to the unwanted, non-radiative channels. We focus on experimentally demonstrated adiabatic controlled population transfer experiments wherein the details on the coherence aspects are yet to be explored theoretically but are important for quantum computation. Such quantum computing schemes also form a back-action connection to coherent control developments.

Generation of Nonclassical Biphoton States through Cascaded Quantum Walks on a Nonlinear Chip

NASA Astrophysics Data System (ADS)

Solntsev, Alexander S.; Setzpfandt, Frank; Clark, Alex S.; Wu, Che Wen; Collins, Matthew J.; Xiong, Chunle; Schreiber, Andreas; Katzschmann, Fabian; Eilenberger, Falk; Schiek, Roland; Sohler, Wolfgang; Mitchell, Arnan; Silberhorn, Christine; Eggleton, Benjamin J.; Pertsch, Thomas; Sukhorukov, Andrey A.; Neshev, Dragomir N.; Kivshar, Yuri S.

2014-07-01

We demonstrate a nonlinear optical chip that generates photons with reconfigurable nonclassical spatial correlations. We employ a quadratic nonlinear waveguide array, where photon pairs are generated through spontaneous parametric down-conversion and simultaneously spread through quantum walks between the waveguides. Because of the quantum interference of these cascaded quantum walks, the emerging photons can become entangled over multiple waveguide positions. We experimentally observe highly nonclassical photon-pair correlations, confirming the high fidelity of on-chip quantum interference. Furthermore, we demonstrate biphoton-state tunability by spatial shaping and frequency tuning of the classical pump beam.

Quantum Communication without Alignment using Multiple-Qubit Single-Photon States

NASA Astrophysics Data System (ADS)

Aolita, L.; Walborn, S. P.

2007-03-01

We propose a scheme for encoding logical qubits in a subspace protected against collective rotations around the propagation axis using the polarization and transverse spatial degrees of freedom of single photons. This encoding allows for quantum key distribution without the need of a shared reference frame. We present methods to generate entangled states of two logical qubits using present day down-conversion sources and linear optics, and show that the application of these entangled logical states to quantum information schemes allows for alignment-free tests of Bell’s inequalities, quantum dense coding, and quantum teleportation.

Investigating and Improving Student Understanding of Key Ideas in Quantum Mechanics throughout Instruction

NASA Astrophysics Data System (ADS)

Emigh, Paul Jeffrey

This dissertation describes research on student understanding of quantum mechanics across multiple levels of instruction. The primary focus has been to identify patterns in student reasoning related to key concepts in quantum mechanics. The specific topics include quantum measurements, time dependence, vector spaces, and angular momentum. The research has spanned a variety of different quantum courses intended for introductory physics students, upper-division physics majors, and graduate students in physics. The results of this research have been used to develop a set of curriculum, Tutorials in Physics: Quantum Mechanics, for addressing the most persistent student difficulties. We document both the development of this curriculum and how it has impacted and improved student understanding of quantum mechanics.

Toward real-time quantum imaging with a single pixel camera

DOE PAGES

Lawrie, B. J.; Pooser, R. C.

2013-03-19

In this paper, we present a workbench for the study of real-time quantum imaging by measuring the frame-by-frame quantum noise reduction of multi-spatial-mode twin beams generated by four wave mixing in Rb vapor. Exploiting the multiple spatial modes of this squeezed light source, we utilize spatial light modulators to selectively pass macropixels of quantum correlated modes from each of the twin beams to a high quantum efficiency balanced detector. Finally, in low-light-level imaging applications, the ability to measure the quantum correlations between individual spatial modes and macropixels of spatial modes with a single pixel camera will facilitate compressive quantum imagingmore » with sensitivity below the photon shot noise limit.« less

Quantum CSMA/CD Synchronous Communication Protocol with Entanglement

NASA Astrophysics Data System (ADS)

Zhou, Nanrun; Zeng, Binyang; Gong, Lihua

By utilizing the characteristics of quantum entanglement, a quantum synchronous communication protocol for Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is presented. The proposed protocol divides the link into the busy time and leisure one, where the data frames are sent via classical channels and the distribution of quantum entanglement is supposed to be completed at leisure time and the quantum acknowledge frames are sent via quantum entanglement channels. The time span between two successfully delivered messages can be significantly reduced in this proposed protocol. It is shown that the performance of the CSMA/CD protocol can be improved significantly since the collision can be reduced to a certain extent. The proposed protocol has great significance in quantum communication.

Generation of multiphoton entangled quantum states by means of integrated frequency combs.

PubMed

Reimer, Christian; Kues, Michael; Roztocki, Piotr; Wetzel, Benjamin; Grazioso, Fabio; Little, Brent E; Chu, Sai T; Johnston, Tudor; Bromberg, Yaron; Caspani, Lucia; Moss, David J; Morandotti, Roberto

2016-03-11

Complex optical photon states with entanglement shared among several modes are critical to improving our fundamental understanding of quantum mechanics and have applications for quantum information processing, imaging, and microscopy. We demonstrate that optical integrated Kerr frequency combs can be used to generate several bi- and multiphoton entangled qubits, with direct applications for quantum communication and computation. Our method is compatible with contemporary fiber and quantum memory infrastructures and with chip-scale semiconductor technology, enabling compact, low-cost, and scalable implementations. The exploitation of integrated Kerr frequency combs, with their ability to generate multiple, customizable, and complex quantum states, can provide a scalable, practical, and compact platform for quantum technologies. Copyright © 2016, American Association for the Advancement of Science.

Multipulse addressing of a Raman quantum memory: configurable beam splitting and efficient readout.

PubMed

Reim, K F; Nunn, J; Jin, X-M; Michelberger, P S; Champion, T F M; England, D G; Lee, K C; Kolthammer, W S; Langford, N K; Walmsley, I A

2012-06-29

Quantum memories are vital to the scalability of photonic quantum information processing (PQIP), since the storage of photons enables repeat-until-success strategies. On the other hand, the key element of all PQIP architectures is the beam splitter, which allows us to coherently couple optical modes. Here, we show how to combine these crucial functionalities by addressing a Raman quantum memory with multiple control pulses. The result is a coherent optical storage device with an extremely large time bandwidth product, that functions as an array of dynamically configurable beam splitters, and that can be read out with arbitrarily high efficiency. Networks of such devices would allow fully scalable PQIP, with applications in quantum computation, long distance quantum communications and quantum metrology.

Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

PubMed Central

Ciotta, Erica; Paoloni, Stefano; Richetta, Maria; Tagliatesta, Pietro; Lorecchio, Chiara; Casciardi, Stefano

2017-01-01

A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu2+, Pb2+ and As(III) was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements and transmission electron microscope (TEM) images we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III) and the formation of precipitate with Pb2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor. PMID:29135946

Quantum spin chains with multiple dynamics

NASA Astrophysics Data System (ADS)

Chen, Xiao; Fradkin, Eduardo; Witczak-Krempa, William

2017-11-01

Many-body systems with multiple emergent time scales arise in various contexts, including classical critical systems, correlated quantum materials, and ultracold atoms. We investigate such nontrivial quantum dynamics in a different setting: a spin-1 bilinear-biquadratic chain. It has a solvable entangled ground state, but a gapless excitation spectrum that is poorly understood. By using large-scale density matrix renormalization group simulations, we find that the lowest excitations have a dynamical exponent z that varies from 2 to 3.2 as we vary a coupling in the Hamiltonian. We find an additional gapless mode with a continuously varying exponent 2 ≤z <2.7 , which establishes the presence of multiple dynamics. In order to explain these striking properties, we construct a continuum wave function for the ground state, which correctly describes the correlations and entanglement properties. We also give a continuum parent Hamiltonian, but show that additional ingredients are needed to capture the excitations of the chain. By using an exact mapping to the nonequilibrium dynamics of a classical spin chain, we find that the large dynamical exponent is due to subdiffusive spin motion. Finally, we discuss the connections to other spin chains and to a family of quantum critical models in two dimensions.

Optimization of carrier multiplication for more effcient solar cells: the case of Sn quantum dots.

PubMed

Allan, Guy; Delerue, Christophe

2011-09-27

We present calculations of impact ionization rates, carrier multiplication yields, and solar-power conversion efficiencies in solar cells based on quantum dots (QDs) of a semimetal, α-Sn. Using these results and previous ones on PbSe and PbS QDs, we discuss a strategy to select QDs with the highest carrier multiplication rate for more efficient solar cells. We suggest using QDs of materials with a close to zero band gap and a high multiplicity of the bands in order to favor the relaxation of photoexcited carriers by impact ionization. Even in that case, the improvement of the maximum solar-power conversion efficiency appears to be a challenging task. © 2011 American Chemical Society

Quantum state sharing against the controller's cheating

NASA Astrophysics Data System (ADS)

Shi, Run-hua; Zhong, Hong; Huang, Liu-sheng

2013-08-01

Most existing QSTS schemes are equivalent to the controlled teleportation, in which a designated agent (i.e., the recoverer) can recover the teleported state with the help of the controllers. However, the controller may attempt to cheat the recoverer during the phase of recovering the secret state. How can we detect this cheating? In this paper, we considered the problem of detecting the controller's cheating in Quantum State Sharing, and further proposed an effective Quantum State Sharing scheme against the controller's cheating. We cleverly use Quantum Secret Sharing, Multiple Quantum States Sharing and decoy-particle techniques. In our scheme, via a previously shared entanglement state Alice can teleport multiple arbitrary multi-qubit states to Bob with the help of Charlie. Furthermore, by the classical information shared previously, Alice and Bob can check whether there is any cheating of Charlie. In addition, our scheme only needs to perform Bell-state and single-particle measurements, and to apply C-NOT gate and other single-particle unitary operations. With the present techniques, it is feasible to implement these necessary measurements and operations.

Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions.

PubMed

Weng, Z F; Smidman, M; Jiao, L; Lu, Xin; Yuan, H Q

2016-09-01

Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.

Performance analysis of quantum access network using code division multiple access model

NASA Astrophysics Data System (ADS)

Hu, Linxi; Yang, Can; He, Guangqiang

2017-06-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 61475099 and 61102053), the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices (Grant No. KF201405), the Open Fund of IPOC (BUPT) (Grant No. IPOC2015B004), and the Program of State Key Laboratory of Information Security (Grant No. 2016-MS-05).

Massive quantum regions for simulations on bio-nanomaterials: synthetic ferritin nanocages.

PubMed

Torras, Juan; Alemán, Carlos

2018-02-22

QM/MM molecular dynamics simulations on the 4His-ΔC* protein cage have been performed using multiple active zones (up to 86 quantum regions). The regulation and nanocage stability exerted by the divalent transition metal ions in the monomer-to-cage conversion have been understood by comparing high level quantum trajectories obtained using Cu 2+ and Ni 2+ coordination ions.

Optimal quantum control of multimode couplings between trapped ion qubits for scalable entanglement.

PubMed

Choi, T; Debnath, S; Manning, T A; Figgatt, C; Gong, Z-X; Duan, L-M; Monroe, C

2014-05-16

We demonstrate entangling quantum gates within a chain of five trapped ion qubits by optimally shaping optical fields that couple to multiple collective modes of motion. We individually address qubits with segmented optical pulses to construct multipartite entangled states in a programmable way. This approach enables high-fidelity gates that can be scaled to larger qubit registers for quantum computation and simulation.

Massive Photons: An Infrared Regularization Scheme for Lattice QCD+QED.

PubMed

Endres, Michael G; Shindler, Andrea; Tiburzi, Brian C; Walker-Loud, André

2016-08-12

Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions.

Wavevector multiplexed atomic quantum memory via spatially-resolved single-photon detection.

PubMed

Parniak, Michał; Dąbrowski, Michał; Mazelanik, Mateusz; Leszczyński, Adam; Lipka, Michał; Wasilewski, Wojciech

2017-12-15

Parallelized quantum information processing requires tailored quantum memories to simultaneously handle multiple photons. The spatial degree of freedom is a promising candidate to facilitate such photonic multiplexing. Using a single-photon resolving camera, we demonstrate a wavevector multiplexed quantum memory based on a cold atomic ensemble. Observation of nonclassical correlations between Raman scattered photons is confirmed by an average value of the second-order correlation function [Formula: see text] in 665 separated modes simultaneously. The proposed protocol utilizing the multimode memory along with the camera will facilitate generation of multi-photon states, which are a necessity in quantum-enhanced sensing technologies and as an input to photonic quantum circuits.

Optimal Measurements for Simultaneous Quantum Estimation of Multiple Phases

NASA Astrophysics Data System (ADS)

Pezzè, Luca; Ciampini, Mario A.; Spagnolo, Nicolò; Humphreys, Peter C.; Datta, Animesh; Walmsley, Ian A.; Barbieri, Marco; Sciarrino, Fabio; Smerzi, Augusto

2017-09-01

A quantum theory of multiphase estimation is crucial for quantum-enhanced sensing and imaging and may link quantum metrology to more complex quantum computation and communication protocols. In this Letter, we tackle one of the key difficulties of multiphase estimation: obtaining a measurement which saturates the fundamental sensitivity bounds. We derive necessary and sufficient conditions for projective measurements acting on pure states to saturate the ultimate theoretical bound on precision given by the quantum Fisher information matrix. We apply our theory to the specific example of interferometric phase estimation using photon number measurements, a convenient choice in the laboratory. Our results thus introduce concepts and methods relevant to the future theoretical and experimental development of multiparameter estimation.

Engineering of lead chalcogenide nanostructures for carrier multiplication: Core/shell, 1D, and 2D

NASA Astrophysics Data System (ADS)

Lin, Qianglu

Near infrared emitting semiconductors have been used widely in industry especially in solar-cell fabrications. The efficiency of single junction solar-cell can reach the Shockley-Queisser limit by using optimum band gap material such as silicon and cadmium telluride. The theoretical efficiency can be further enhanced through carrier multiplication, in which a high energy photon is absorbed and more than one electron-hole pair can be generated, reaching more than 100% quantum efficiency in the high energy region of sunlight. The realization of more than unity external quantum efficiency in lead selenide quantum dots solar cell has motivated vast investigation on lowering the carrier multiplication threshold and further improving the efficiency. This dissertation focuses on synthesis of lead chalcogenide nanostructures for their optical spectroscopy studies. PbSe/CdSe core/shell quantum dots were synthesized by cation exchange to obtain thick shells (up to 14 monolayers) for studies of visible and near infrared dual band emissions and carrier multiplication efficiency. By examining the reaction mechanism, a thermodynamic and a kinetic model are introduced to explain the vacancy driven cation exchange. As indicated by the effective mass model, PbSe/CdSe core/shell quantum dots has quasi-type-II band alignment, possessing electron delocalized through the entire quantum dot and hole localized in the core, which breaks down the symmetry of energy levels in the conduction and valence band, leading to hot-hole-assisted efficient multi-exciton generation and a lower carrier multiplication threshold to the theoretical value. For further investigation of carrier multiplication study, PbTe, possessing the highest efficiency among lead chalcogenides due to slow intraband cooling, is synthesized in one-dimensional and two-dimensional nanostructures. By using dodecanethiol as the surfactant, PbTe NRs can be prepared with high uniformity in width and resulted in fine quantum confinement features. The reaction can be explained by a soft-template assisted process, in which the lamellar lead-thiolate precursor transforms into rod-shape micelle in the existence of telluride anions by electrostatic attraction. Fine tuning the reaction condition by changing the solvent to oleylamine, lead telluride nanowires with length up to 200 nm can be prepared, which bundled together because of the strong dipole-dipole attraction between nanowires. Decreasing the amount of surfactant dodecanethiol in the synthesis produces lead telluride nanorings, which formed by attaching four small particles together, leaving the center void. To prepare two-dimensional nanoplatelets, mixture ligands containing two amines with different carbon chain length were used, which initiate oriented attachment of the nanoparticles to form square-shape nanoplatelets. By further adopting stronger binding ligands such as phosphonic acid, PbTe nanoplatelets with micrometer lateral dimension were prepared with extremely sharp near infrared photoluminescence (less than 40 meV), which has never be achieved in quantum dots and other nanostructures.

Competition Between Pairing and Ferromagnetic Instabilities in Ultracold Fermi Gases Near Feshbach Resonances

DTIC Science & Technology

2010-05-13

see the inset of Fig. 1). Thus, the two-body pairing process becomes for- bidden when the binding energy ∼ 1/ ma2 exceeds the maxi- mum energy that can...matrix in vacuum. For each value of the scattering length, the T-matrix has a line of poles on the BEC side located at ωq = Ωq+i∆q = −1/ ma2 + mq2/4

Posturing Tactical ISR Beyond The Umbilical Cord

DTIC Science & Technology

2017-02-03

intelligence sensors, it carries a lethal payload of ordinance for strike and or close air support missions. In fact, world media have discussed the MQ-9’s...awareness all their visual and signal intelligence sensors provide is a force multiplier that enhances mission success significantly. For example, when...on C-17 Photo Source http://www.aircav.com/dodphoto/dod98/mh60-002rs.jpg 407MRH multirole armed ISR ( intelligence , surveillance, reconnaissance

From A Distance: The Psychology Of Killing With Remotely Piloted Aircraft

DTIC Science & Technology

2015-01-01

community. The continuing ethical and moral relativism society uses to place new weapons and methods on the battlefield are in plain view with the MQ-1... cultural , social, moral , and technological sub-categories.44 Cultural distancing is a method most commonly used to dehumanize an enemy, effectively...psychological response, emotional distance retains a key role in the overall process. On Killing states, “Factors such as cultural distance, moral

Injection current dependences of electroluminescence transition energy in InGaN/GaN multiple quantum wells light emitting diodes under pulsed current conditions

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

Zhang, Feng; Ikeda, Masao, E-mail: mikeda2013@sinano.ac.cn; Liu, Jianping

2015-07-21

Injection current dependences of electroluminescence transition energy in blue InGaN/GaN multiple quantum wells light emitting diodes (LEDs) with different quantum barrier thicknesses under pulsed current conditions have been analyzed taking into account the related effects including deformation caused by lattice strain, quantum confined Stark effects due to polarization field partly screened by carriers, band gap renormalization, Stokes-like shift due to compositional fluctuations which are supposed to be random alloy fluctuations in the sub-nanometer scale, band filling effect (Burstein-Moss shift), and quantum levels in finite triangular wells. The bandgap renormalization and band filling effect occurring at high concentrations oppose one another,more » however, the renormalization effect dominates in the concentration range studied, since the band filling effect arising from the filling in the tail states in the valence band of quantum wells is much smaller than the case in the bulk materials. In order to correlate the carrier densities with current densities, the nonradiative recombination rates were deduced experimentally by curve-fitting to the external quantum efficiencies. The transition energies in LEDs both with 15 nm quantum barriers and 5 nm quantum barriers, calculated using full strengths of theoretical macroscopic polarization given by Barnardini and Fiorentini [Phys. Status Solidi B 216, 391 (1999)] are in excellent accordance with experimental results. The LED with 5 nm barriers has been shown to exhibit a higher transition energy and a smaller blue shift than those of LED with 15 nm barriers, which is mainly caused by the smaller internal polarization field in the quantum wells.« less

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

Huang, Yang; Liu, Zhiqiang, E-mail: lzq@semi.ac.cn, E-mail: spring@semi.ac.cn; Yi, Xiaoyan, E-mail: lzq@semi.ac.cn, E-mail: spring@semi.ac.cn

To evaluate electron leakage in InGaN/GaN multiple quantum well (MQW) light emitting diodes (LEDs), analytic models of ballistic and quasi-ballistic transport are developed. With this model, the impact of critical variables effecting electron leakage, including the electron blocking layer (EBL), structure of multiple quantum wells (MQWs), polarization field, and temperature are explored. The simulated results based on this model shed light on previously reported experimental observations and provide basic criteria for suppressing electron leakage, advancing the design of InGaN/GaN LEDs.

Nuclear Magnetic Resonance Nondestructive Evaluation of Composite Materials

DTIC Science & Technology

1990-04-09

Pat. Appl. EP 26265, 8 Apr 1981, 13 pp. (1981). 9. A. N. Garroway , J. Baum, M. G. Munowitz, and A. Pines, NMR Imaging in Solids by Multiple-Quantum...Resonance, J. Magn. Reson. 60(2), 337-41 (1984). 10. J. Baum, A. N. Garroway , M. Munowitz, and A. Pines, Multiple-Quantum NMR in Solids: Application to... Garroway , NMR Images of Solids, J. Magn. Reson. 66(3), 530-5 (1986). 28. J. B. Miller and A. N. Garroway , Removal of Static Field Inhomogeneity and

Entropic Uncertainty Relation and Information Exclusion Relation for multiple measurements in the presence of quantum memory

PubMed Central

Zhang, Jun; Zhang, Yang; Yu, Chang-shui

2015-01-01

The Heisenberg uncertainty principle shows that no one can specify the values of the non-commuting canonically conjugated variables simultaneously. However, the uncertainty relation is usually applied to two incompatible measurements. We present tighter bounds on both entropic uncertainty relation and information exclusion relation for multiple measurements in the presence of quantum memory. As applications, three incompatible measurements on Werner state and Horodecki’s bound entangled state are investigated in details. PMID:26118488

Low loss InGaAs/InP multiple quantum well waveguides

NASA Astrophysics Data System (ADS)

Koren, U.; Miller, B. I.; Koch, T. L.; Boyd, G. D.; Capik, R. J.

1986-12-01

Double heterostructure planar waveguides with an InGaAs/InP multiple quantum well (MQW) core and InP cladding layers were grown by atmospheric pressure metalorganic chemical vapor deposition. Ridge waveguides had a low propagation loss of 0.8 dB/cm for 1.52 micron input light. The indices of refraction for the guided TE and TM modes have been measured and the bulk dispersion curves of the MQW material for the 1.46-1.55 micron wavelength region were derived.

Emission wavelength of AlGaAs-GaAs multiple quantum well lasers

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

Blood, P.; Fletcher, E.D.; Hulyer, P.J.

1986-04-28

We have recorded spontaneous emission spectra from multiple quantum well lasers grown by molecular beam epitaxy with 25-A-wide GaAs wells by opening a window in the top contact stripe. These spectra have a low-energy tail and consequently the gain spectra derived from them show that laser emission occurs at a lower photon energy than the lowest energy confined particle transition. The observed laser wavelength and threshold current are consistent with the position of the peak in the gain spectrum.

Quantum coherence via skew information and its polygamy

NASA Astrophysics Data System (ADS)

Yu, Chang-shui

2017-04-01

Quantifying coherence is a key task in both quantum-mechanical theory and practical applications. Here, a reliable quantum coherence measure is presented by utilizing the quantum skew information of the state of interest subject to a certain broken observable. This coherence measure is proven to fulfill all the criteria (especially the strong monotonicity) recently introduced in the resource theories of quantum coherence. The coherence measure has an analytic expression and an obvious operational meaning related to quantum metrology. In terms of this coherence measure, the distribution of the quantum coherence, i.e., how the quantum coherence is distributed among the multiple parties, is studied and a corresponding polygamy relation is proposed. As a further application, it is found that the coherence measure forms the natural upper bounds for quantum correlations prepared by incoherent operations. The experimental measurements of our coherence measure as well as the relative-entropy coherence and lp-norm coherence are studied finally.

Photoluminescence of ZnTe/ZnMgTe multiple quantum well structures grown on ZnTe substrates by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Tanaka, Tooru; Ohshita, Hiroshi; Saito, Katsuhiko; Guo, Qixin

2018-02-01

Photoluminescence (PL) properties of ZnTe/ZnMgTe quantum well (QW) structures grown by molecular beam epitaxy (MBE) were investigated systematically with respect to well widths and Mg contents. Observed PL peak energies were consistent well with the calculated emission energies of the QWs considering a lattice distortion in the ZnTe well. From the temperature dependence of PL intensity, it was found that a suppression of a carrier escape from QW is crucial to obtain a PL at higher temperature in the ZnTe/ZnMgTe QW. Based on the results, multiple quantum well structures were designed and fabricated, which exhibited a green PL at room temperature.

Robust Multiple-Range Coherent Quantum State Transfer.

PubMed

Chen, Bing; Peng, Yan-Dong; Li, Yong; Qian, Xiao-Feng

2016-07-01

We propose a multiple-range quantum communication channel to realize coherent two-way quantum state transport with high fidelity. In our scheme, an information carrier (a qubit) and its remote partner are both adiabatically coupled to the same data bus, i.e., an N-site tight-binding chain that has a single defect at the center. At the weak interaction regime, our system is effectively equivalent to a three level system of which a coherent superposition of the two carrier states constitutes a dark state. The adiabatic coupling allows a well controllable information exchange timing via the dark state between the two carriers. Numerical results show that our scheme is robust and efficient under practically inevitable perturbative defects of the data bus as well as environmental dephasing noise.

Design and Synthesis of Antiblinking and Antibleaching Quantum Dots in Multiple Colors via Wave Function Confinement.

PubMed

Cao, Hujia; Ma, Junliang; Huang, Lin; Qin, Haiyan; Meng, Renyang; Li, Yang; Peng, Xiaogang

2016-12-07

Single-molecular spectroscopy reveals that photoluminescence (PL) of a single quantum dot blinks, randomly switching between bright and dim/dark states under constant photoexcitation, and quantum dots photobleach readily. These facts cast great doubts on potential applications of these promising emitters. After ∼20 years of efforts, synthesis of nonblinking quantum dots is still challenging, with nonblinking quantum dots only available in red-emitting window. Here we report synthesis of nonblinking quantum dots covering most part of the visible window using a new synthetic strategy, i.e., confining the excited-state wave functions of the core/shell quantum dots within the core quantum dot and its inner shells (≤ ∼5 monolayers). For the red-emitting ones, the new synthetic strategy yields nonblinking quantum dots with small sizes (∼8 nm in diameter) and improved nonblinking properties. These new nonblinking quantum dots are found to be antibleaching. Results further imply that the PL blinking and photobleaching of quantum dots are likely related to each other.

Emulation of complex open quantum systems using superconducting qubits

NASA Astrophysics Data System (ADS)

Mostame, Sarah; Huh, Joonsuk; Kreisbeck, Christoph; Kerman, Andrew J.; Fujita, Takatoshi; Eisfeld, Alexander; Aspuru-Guzik, Alán

2017-02-01

With quantum computers being out of reach for now, quantum simulators are alternative devices for efficient and accurate simulation of problems that are challenging to tackle using conventional computers. Quantum simulators are classified into analog and digital, with the possibility of constructing "hybrid" simulators by combining both techniques. Here we focus on analog quantum simulators of open quantum systems and address the limit that they can beat classical computers. In particular, as an example, we discuss simulation of the chlorosome light-harvesting antenna from green sulfur bacteria with over 250 phonon modes coupled to each electronic state. Furthermore, we propose physical setups that can be used to reproduce the quantum dynamics of a standard and multiple-mode Holstein model. The proposed scheme is based on currently available technology of superconducting circuits consist of flux qubits and quantum oscillators.

Hybrid Toffoli gate on photons and quantum spins

PubMed Central

Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

2015-01-01

Quantum computation offers potential advantages in solving a number of interesting and difficult problems. Several controlled logic gates, the elemental building blocks of quantum computer, have been realized with various physical systems. A general technique was recently proposed that significantly reduces the realization complexity of multiple-control logic gates by harnessing multi-level information carriers. We present implementations of a key quantum circuit: the three-qubit Toffoli gate. By exploring the optical selection rules of one-sided optical microcavities, a Toffoli gate may be realized on all combinations of photon and quantum spins in the QD-cavity. The three general controlled-NOT gates are involved using an auxiliary photon with two degrees of freedom. Our results show that photons and quantum spins may be used alternatively in quantum information processing. PMID:26568078

Hybrid Toffoli gate on photons and quantum spins.

PubMed

Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

2015-11-16

Quantum computation offers potential advantages in solving a number of interesting and difficult problems. Several controlled logic gates, the elemental building blocks of quantum computer, have been realized with various physical systems. A general technique was recently proposed that significantly reduces the realization complexity of multiple-control logic gates by harnessing multi-level information carriers. We present implementations of a key quantum circuit: the three-qubit Toffoli gate. By exploring the optical selection rules of one-sided optical microcavities, a Toffoli gate may be realized on all combinations of photon and quantum spins in the QD-cavity. The three general controlled-NOT gates are involved using an auxiliary photon with two degrees of freedom. Our results show that photons and quantum spins may be used alternatively in quantum information processing.

A quantum extended Kalman filter

NASA Astrophysics Data System (ADS)

Emzir, Muhammad F.; Woolley, Matthew J.; Petersen, Ian R.

2017-06-01

In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements.

Influence of Silver and Gold Nanoparticles and Thin Layers on Charge Carrier Generation in InGaN/GaN Multiple Quantum Well Structures and Crystalline Zinc Oxide Films

NASA Astrophysics Data System (ADS)

Mezdrogina, M. M.; Vinogradov, A. Ya.; Kozhanova, Yu. V.; Levitskii, V. S.

2018-04-01

It has been shown that Ag and Au nanoparticles and thin layers influence charge carrier generation in InGaN/GaN multiple quantum well structures and crystalline ZnO films owing to the surface morphology heterogeneity of the semiconductors. When nanoparticles 10 < d < 20 nm in size are applied on InGaN/GaN multiple quantum well structures with surface morphology less nonuniform than that of ZnO films, the radiation intensity has turned out to grow considerably because of a plasmon resonance with the participation of localized plasmons. The application of Ag or Au layers on the surface of the structures strongly attenuates the radiation. When Ag and Au nanoparticles are applied on crystalline ZnO films obtained by rf magnetron sputtering, the radiation intensity in the short-wavelength part of the spectrum increases insignificantly because of their highly heterogeneous surface morphology.

Monolithic integration of InGaAs/InP multiple quantum wells on SOI substrates for photonic devices

NASA Astrophysics Data System (ADS)

Li, Zhibo; Wang, Mengqi; Fang, Xin; Li, Yajie; Zhou, Xuliang; Yu, Hongyan; Wang, Pengfei; Wang, Wei; Pan, Jiaoqing

2018-02-01

A direct epitaxy of III-V nanowires with InGaAs/InP multiple quantum wells on v-shaped trenches patterned silicon on insulator (SOI) substrates was realized by combining the standard semiconductor fabrication process with the aspect ratio trapping growth technique. Silicon thickness as well as the width and gap of each nanowire were carefully designed to accommodate essential optical properties and appropriate growth conditions. The III-V element ingredient, crystalline quality, and surface topography of the grown nanowires were characterized by X-ray diffraction spectroscopy, photoluminescence, and scanning electron microscope. Geometrical details and chemical information of multiple quantum wells were revealed by transmission electron microscopy and energy dispersive spectroscopy. Numerical simulations confirmed that the optical guided mode supported by one single nanowire was able to propagate 50 μm with ˜30% optical loss. This proposed integration scheme opens up an alternative pathway for future photonic integrations of III-V devices on the SOI platform at nanoscale.

Implementation of generalized quantum measurements for unambiguous discrimination of multiple non-orthogonal coherent states.

PubMed

Becerra, F E; Fan, J; Migdall, A

2013-01-01

Generalized quantum measurements implemented to allow for measurement outcomes termed inconclusive can perform perfect discrimination of non-orthogonal states, a task which is impossible using only measurements with definitive outcomes. Here we demonstrate such generalized quantum measurements for unambiguous discrimination of four non-orthogonal coherent states and obtain their quantum mechanical description, the positive-operator valued measure. For practical realizations of this positive-operator valued measure, where noise and realistic imperfections prevent perfect unambiguous discrimination, we show that our experimental implementation outperforms any ideal standard-quantum-limited measurement performing the same non-ideal unambiguous state discrimination task for coherent states with low mean photon numbers.

Electroreflectance spectra from multiple InGaN/GaN quantum wells in the nonuniform electric field of a p–n junction

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

Avakyants, L. P.; Aslanyan, A. E.; Bokov, P. Yu., E-mail: pavel-bokov@physics.msu.ru

A line at E = 2.77 eV (with a width of Γ = 88 meV) related to interband transitions in the region of multiple quantum wells in the active region is detected in the electroreflectance spectra of the GaN/InGaN/AlGaN heterostructure. As the modulation bias is reduced from 2.9 to 0.4 V, the above line is split into two lines with energies of E{sub 1} = 2.55 eV and E{sub 2} = 2.75 eV and widths of Γ{sub 1} = 66 meV and Γ{sub 2} = 74 meV, respectively. The smaller widths of separate lines indicate that these lines are causedmore » by interband transitions in particular quantum wells within the active region. The difference between the interband transition energies E{sub 1} and E{sub 2} in identical quantum wells in the active region is related to the fact that the quantum wells are in an inhomogeneous electric field of the p–n junction. The magnitudes of the electric-field strengths in particular quantum wells in the active region of the heterostructure are estimated to be 1.6 and 2.2 MV/cm.« less

Single-photon three-qubit quantum logic using spatial light modulators.

PubMed

Kagalwala, Kumel H; Di Giuseppe, Giovanni; Abouraddy, Ayman F; Saleh, Bahaa E A

2017-09-29

The information-carrying capacity of a single photon can be vastly expanded by exploiting its multiple degrees of freedom: spatial, temporal, and polarization. Although multiple qubits can be encoded per photon, to date only two-qubit single-photon quantum operations have been realized. Here, we report an experimental demonstration of three-qubit single-photon, linear, deterministic quantum gates that exploit photon polarization and the two-dimensional spatial-parity-symmetry of the transverse single-photon field. These gates are implemented using a polarization-sensitive spatial light modulator that provides a robust, non-interferometric, versatile platform for implementing controlled unitary gates. Polarization here represents the control qubit for either separable or entangling unitary operations on the two spatial-parity target qubits. Such gates help generate maximally entangled three-qubit Greenberger-Horne-Zeilinger and W states, which is confirmed by tomographical reconstruction of single-photon density matrices. This strategy provides access to a wide range of three-qubit states and operations for use in few-qubit quantum information processing protocols.Photons are essential for quantum information processing, but to date only two-qubit single-photon operations have been realized. Here the authors demonstrate experimentally a three-qubit single-photon linear deterministic quantum gate by exploiting polarization along with spatial-parity symmetry.

Hippocampal Volume Reduction in Humans Predicts Impaired Allocentric Spatial Memory in Virtual-Reality Navigation

PubMed Central

Dzieciol, Anna M.; Gadian, David G.; Jentschke, Sebastian; Doeller, Christian F.; Burgess, Neil; Mishkin, Mortimer

2015-01-01

The extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated allocentric spatial recall using a virtual environment in a group of patients with severe hippocampal damage (SHD), a group of patients with “moderate” hippocampal damage (MHD), and a normal control group. Through four learning blocks with feedback, participants learned the target locations of four different objects in a circular arena. Distal cues were present throughout the experiment to provide orientation. A circular boundary as well as an intra-arena landmark provided spatial reference frames. During a subsequent test phase, recall of all four objects was tested with only the boundary or the landmark being present. Patients with SHD were impaired in both phases of this task. Across groups, performance on both types of spatial recall was highly correlated with memory quotient (MQ), but not with intelligence quotient (IQ), age, or sex. However, both measures of spatial recall separated experimental groups beyond what would be expected based on MQ, a widely used measure of general memory function. Boundary-based and landmark-based spatial recall were both strongly related to bilateral hippocampal volumes, but not to volumes of the thalamus, putamen, pallidum, nucleus accumbens, or caudate nucleus. The results show that boundary-based and landmark-based allocentric spatial recall are similarly impaired in patients with SHD, that both types of recall are impaired beyond that predicted by MQ, and that recall deficits are best explained by a reduction in bilateral hippocampal volumes. SIGNIFICANCE STATEMENT In humans, bilateral hippocampal atrophy can lead to profound impairments in episodic memory. Across species, perhaps the most well-established contribution of the hippocampus to memory is not to episodic memory generally but to allocentric spatial memory. However, the extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated spatial recall using a virtual environment in two groups of patients with hippocampal damage (moderate/severe) and a normal control group. The results showed that patients with severe hippocampal damage are impaired in learning and recalling allocentric spatial information. Furthermore, hippocampal volume reduction impaired allocentric navigation beyond what can be predicted by memory quotient as a widely used measure of general memory function. PMID:26490854

Hippocampal Volume Reduction in Humans Predicts Impaired Allocentric Spatial Memory in Virtual-Reality Navigation.

PubMed

Guderian, Sebastian; Dzieciol, Anna M; Gadian, David G; Jentschke, Sebastian; Doeller, Christian F; Burgess, Neil; Mishkin, Mortimer; Vargha-Khadem, Faraneh

2015-10-21

The extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated allocentric spatial recall using a virtual environment in a group of patients with severe hippocampal damage (SHD), a group of patients with "moderate" hippocampal damage (MHD), and a normal control group. Through four learning blocks with feedback, participants learned the target locations of four different objects in a circular arena. Distal cues were present throughout the experiment to provide orientation. A circular boundary as well as an intra-arena landmark provided spatial reference frames. During a subsequent test phase, recall of all four objects was tested with only the boundary or the landmark being present. Patients with SHD were impaired in both phases of this task. Across groups, performance on both types of spatial recall was highly correlated with memory quotient (MQ), but not with intelligence quotient (IQ), age, or sex. However, both measures of spatial recall separated experimental groups beyond what would be expected based on MQ, a widely used measure of general memory function. Boundary-based and landmark-based spatial recall were both strongly related to bilateral hippocampal volumes, but not to volumes of the thalamus, putamen, pallidum, nucleus accumbens, or caudate nucleus. The results show that boundary-based and landmark-based allocentric spatial recall are similarly impaired in patients with SHD, that both types of recall are impaired beyond that predicted by MQ, and that recall deficits are best explained by a reduction in bilateral hippocampal volumes. In humans, bilateral hippocampal atrophy can lead to profound impairments in episodic memory. Across species, perhaps the most well-established contribution of the hippocampus to memory is not to episodic memory generally but to allocentric spatial memory. However, the extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated spatial recall using a virtual environment in two groups of patients with hippocampal damage (moderate/severe) and a normal control group. The results showed that patients with severe hippocampal damage are impaired in learning and recalling allocentric spatial information. Furthermore, hippocampal volume reduction impaired allocentric navigation beyond what can be predicted by memory quotient as a widely used measure of general memory function. Copyright © 2015 Guderian et al.

New approach to the resummation of logarithms in Higgs-boson decays to a vector quarkonium plus a photon

NASA Astrophysics Data System (ADS)

Bodwin, Geoffrey T.; Chung, Hee Sok; Ee, June-Haak; Lee, Jungil

2017-03-01

We present a calculation of the rates for Higgs-boson decays to a vector heavy-quarkonium state plus a photon, where the heavy-quarkonium states are the J /ψ and the ϒ (n S ) states, with n =1 , 2, or 3. The calculation is carried out in the light-cone formalism, combined with nonrelativistic QCD factorization, and is accurate at leading order in mQ2/mH2, where mQ is the heavy-quark mass and mH is the Higgs-boson mass. The calculation contains corrections through next-to-leading order in the strong-coupling constant αs and the square of the heavy-quark velocity v , and includes a resummation of logarithms of mH2/mQ2 at next-to-leading logarithmic accuracy. We have developed a new method, which makes use of Abel summation, accelerated through the use of Padé approximants, to deal with divergences in the resummed expressions for the quarkonium light-cone distribution amplitudes. This approach allows us to make definitive calculations of the resummation effects. Contributions from the order-αs and order-v2 corrections to the light-cone distribution amplitudes that we obtain with this new method differ substantially from the corresponding contributions that one obtains from a model light-cone distribution amplitude [M. König and M. Neubert, J. High Energy Phys. 08 (2015) 012, 10.1007/JHEP08(2015)012]. Our results for the real parts of the direct-process amplitudes are considerably smaller than those from one earlier calculation [G. T. Bodwin, H. S. Chung, J.-H. Ee, J. Lee, and F. Petriello, Phys. Rev. D 90, 113010 (2014), 10.1103/PhysRevD.90.113010], reducing the sensitivity to the Higgs-boson-heavy-quark couplings, and are somewhat smaller than those from another earlier calculation [M. König and M. Neubert, J. High Energy Phys. 08 (2015) 012, 10.1007/JHEP08(2015)012]. However, our results for the standard-model Higgs-boson branching fractions are in good agreement with those in M. König and M. Neubert, J. High Energy Phys. 08 (2015) 012, 10.1007/JHEP08(2015)012.

Bovine Teat Microbiome Analysis Revealed Reduced Alpha Diversity and Significant Changes in Taxonomic Profiles in Quarters with a History of Mastitis

PubMed Central

Falentin, Hélène; Rault, Lucie; Nicolas, Aurélie; Bouchard, Damien S.; Lassalas, Jacques; Lamberton, Philippe; Aubry, Jean-Marc; Marnet, Pierre-Guy; Le Loir, Yves; Even, Sergine

2016-01-01

Mastitis is a mammary gland inflammatory disease often due to bacterial infections. Like many other infections, it used to be considered as a host-pathogen interaction driven by host and bacterial determinants. Until now, the involvement of the bovine mammary gland microbiota in the host-pathogen interaction has been poorly investigated, and mainly during the infectious episode. In this study, the bovine teat microbiome was investigated in 31 quarters corresponding to 27 animals, which were all free of inflammation at sampling time but which had different histories regarding mastitis: from no episode of mastitis on all the previous lactations (Healthy quarter, Hq) to one or several clinical mastitis events (Mastitic quarter, Mq). Several quarters whose status was unclear (possible history of subclinical mastitis) were classified as NDq. Total bacterial DNA was extracted from foremilk samples and swab samples of the teat canal. Taxonomic profiles were determined by pyrosequencing on 16s amplicons of the V3-4 region. Hq quarters showed a higher diversity compared to Mq ones (Shannon index: ~8 and 6, respectively). Clustering of the quarters based on their bacterial composition made it possible to separate Mq and Hq quarters into two separate clusters (C1 and C2, respectively). Discriminant analysis of taxonomic profiles between these clusters revealed several differences and allowed the identification of taxonomic markers in relation to mastitis history. C2 quarters were associated with a higher proportion of the Clostridia class (including genera such as Ruminococcus, Oscillospira, Roseburia, Dorea, etc.), the Bacteroidetes phylum (Prevotella, Bacteroides, Paludibacter, etc.), and the Bifidobacteriales order (Bifidobacterium), whereas C1 quarters showed a higher proportion of the Bacilli class (Staphylococcus) and Chlamydiia class. These results indicate that microbiota is altered in udders which have already developed mastitis, even far from the infectious episode. Microbiome alteration may have resulted from the infection itself and or the associated antibiotic treatment. Alternatively, differences in microbiome composition in udders with a history of mastitis may have occurred prior to the infection and even contributed to infection development. Further investigations on the dynamics of mammary gland microbiota will help to elucidate the contribution of this endogenous microbiota to the mammary gland health. PMID:27242672

Effect of artesunate-mefloquine fixed-dose combination in malaria transmission in amazon basin communities

PubMed Central

2012-01-01

Background Studies in South-East Asia have suggested that early diagnosis and treatment with artesunate (AS) and mefloquine (MQ) combination therapy may reduce the transmission of Plasmodium falciparum malaria and the progression of MQ resistance. Methods The effectiveness of a fixed-dose combination of AS and MQ (ASMQ) in reducing malaria transmission was tested in isolated communities of the Juruá valley in the Amazon region. Priority municipalities within the Brazilian Legal Amazon area were selected according to pre-specified criteria. Routine national malaria control programmatic procedures were followed. Existing health structures were reinforced and health care workers were trained to treat with ASMQ all confirmed falciparum malaria cases that match inclusion criteria. A local pharmacovigilance structure was implemented. Incidence of malaria and hospitalizations were recorded two years before, during, and after the fixed-dose ASMQ intervention. In total, between July 2006 and December 2008, 23,845 patients received ASMQ. Two statistical modelling approaches were applied to monthly time series of P. falciparum malaria incidence rates, P. falciparum/Plasmodium vivax infection ratio, and malaria hospital admissions rates. All the time series ranged from January 2004 to December 2008, whilst the intervention period span from July 2006 to December 2008. Results The ASMQ intervention had a highly significant impact on the mean level of each time series, adjusted for trend and season, of 0.34 (95%CI 0.20 – 0.58) for the P. falciparum malaria incidence rates, 0.67 (95%CI 0.50 – 0.89) for the P. falciparum/P. vivax infection ratio, and 0.53 (95%CI 0.41 – 0.69) for the hospital admission rates. There was also a significant change in the seasonal (or monthly) pattern of the time series before and after intervention, with the elimination of the malaria seasonal peak in the rainy months of the years following the introduction of ASMQ. No serious adverse events relating to the use of fixed-dose ASMQ were reported. Conclusions In the remote region of the Juruá valley, the early detection of malaria by health care workers and treatment with fixed-dose ASMQ was feasible and efficacious, and significantly reduced the incidence and morbidity of P. falciparum malaria. PMID:22905900

Quantum demultiplexer of quantum parameter-estimation information in quantum networks

NASA Astrophysics Data System (ADS)

Xie, Yanqing; Huang, Yumeng; Wu, Yinzhong; Hao, Xiang

2018-05-01

The quantum demultiplexer is constructed by a series of unitary operators and multipartite entangled states. It is used to realize information broadcasting from an input node to multiple output nodes in quantum networks. The scheme of quantum network communication with respect to phase estimation is put forward through the demultiplexer subjected to amplitude damping noises. The generalized partial measurements can be applied to protect the transferring efficiency from environmental noises in the protocol. It is found out that there are some optimal coherent states which can be prepared to enhance the transmission of phase estimation. The dynamics of state fidelity and quantum Fisher information are investigated to evaluate the feasibility of the network communication. While the state fidelity deteriorates rapidly, the quantum Fisher information can be enhanced to a maximum value and then decreases slowly. The memory effect of the environment induces the oscillations of fidelity and quantum Fisher information. The adjustment of the strength of partial measurements is helpful to increase quantum Fisher information.

Minimum Dimension of a Hilbert Space Needed to Generate a Quantum Correlation.

PubMed

Sikora, Jamie; Varvitsiotis, Antonios; Wei, Zhaohui

2016-08-05

Consider a two-party correlation that can be generated by performing local measurements on a bipartite quantum system. A question of fundamental importance is to understand how many resources, which we quantify by the dimension of the underlying quantum system, are needed to reproduce this correlation. In this Letter, we identify an easy-to-compute lower bound on the smallest Hilbert space dimension needed to generate a given two-party quantum correlation. We show that our bound is tight on many well-known correlations and discuss how it can rule out correlations of having a finite-dimensional quantum representation. We show that our bound is multiplicative under product correlations and also that it can witness the nonconvexity of certain restricted-dimensional quantum correlations.

Quantum cascade light emitting diodes based on type-2 quantum wells

NASA Technical Reports Server (NTRS)

Lin, C. H.; Yang, R. Q.; Zhang, D.; Murry, S. J.; Pei, S. S.; Allerman, A. A.; Kurtz, S. R.

1997-01-01

The authors have demonstrated room-temperature CW operation of type-2 quantum cascade (QC) light emitting diodes at 4.2 (micro)m using InAs/InGaSb/InAlSb type-2 quantum wells. The type-2 QC configuration utilizes sequential multiple photon emissions in a staircase of coupled type-2 quantum wells. The device was grown by molecular beam epitaxy on a p-type GaSb substrate and was compared of 20 periods of active regions separated by digitally graded quantum well injection regions. The maximum average output power is about 250 (micro)W at 80 K, and 140 (micro)W at 300 K at a repetition rate of 1 kHz with a duty cycle of 50%.

Superposing pure quantum states with partial prior information

NASA Astrophysics Data System (ADS)

Dogra, Shruti; Thomas, George; Ghosh, Sibasish; Suter, Dieter

2018-05-01

The principle of superposition is an intriguing feature of quantum mechanics, which is regularly exploited in many different circumstances. A recent work [M. Oszmaniec et al., Phys. Rev. Lett. 116, 110403 (2016), 10.1103/PhysRevLett.116.110403] shows that the fundamentals of quantum mechanics restrict the process of superimposing two unknown pure states, even though it is possible to superimpose two quantum states with partial prior knowledge. The prior knowledge imposes geometrical constraints on the choice of input states. We discuss an experimentally feasible protocol to superimpose multiple pure states of a d -dimensional quantum system and carry out an explicit experimental realization for two single-qubit pure states with partial prior information on a two-qubit NMR quantum information processor.

Quantum molecular dynamics and multistep-direct analyses of multiple preequilibrium emission

NASA Astrophysics Data System (ADS)

Chadwick, M. B.; Chiba, S.; Niita, K.; Maruyama, T.; Iwamoto, A.

1995-11-01

We study multiple preequilibrium emission in nucleon induced reactions at intermediate energies, and compare quantum molecular dynamics (QMD) calculations with multistep-direct Feshbach-Kerman-Koonin results [M. B. Chadwick, P. G. Young, D. C. George, and Y. Watanabe, Phys. Rev. C 50, 996 (1994)]. When the theoretical expressions of this reference are reformulated so that the definitions of primary and multiple emission correspond to those used in QMD, the two theories yield similar results for primary and multiple preequilibrium emission. We use QMD as a tool to determine the multiplicities of fast preequilibrium nucleons as a function of incident energy. For fast particle cross sections to exceed 5% of the inclusive preequilibrium emission cross sections we find that two particles should be included in reactions above 50 MeV, three above about 180 MeV, and four are only needed when the incident energy exceeds about 400 MeV.

An Integrated Development Environment for Adiabatic Quantum Programming

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

Humble, Travis S; McCaskey, Alex; Bennink, Ryan S

2014-01-01

Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware raises the question of how well quantum programs perform. Benchmarking behavior is challenging since the multiple steps to synthesize an adiabatic quantum program are highly tunable. We present an adiabatic quantum programming environment called JADE that provides control over all the steps taken during program development. JADE captures the workflow needed to rigorously benchmark performance while also allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation enginemore » that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its use for benchmarking adiabatic quantum programs.« less

Quantum Secure Group Communication.

PubMed

Li, Zheng-Hong; Zubairy, M Suhail; Al-Amri, M

2018-03-01

We propose a quantum secure group communication protocol for the purpose of sharing the same message among multiple authorized users. Our protocol can remove the need for key management that is needed for the quantum network built on quantum key distribution. Comparing with the secure quantum network based on BB84, we show our protocol is more efficient and securer. Particularly, in the security analysis, we introduce a new way of attack, i.e., the counterfactual quantum attack, which can steal information by "invisible" photons. This invisible photon can reveal a single-photon detector in the photon path without triggering the detector. Moreover, the photon can identify phase operations applied to itself, thereby stealing information. To defeat this counterfactual quantum attack, we propose a quantum multi-user authorization system. It allows us to precisely control the communication time so that the attack can not be completed in time.

[Imaging of surface cell antigens on the tumor sections of lymph nodes using fluorescence quantum dots].

PubMed

Rafalovskaia-Orlovskaia, E P; Gorgidze, L A; Gladkikh, A A; Tauger, S M; Vorob'ev, I A

2012-01-01

The usefulness of quantum dots for the immunofluorescent detection of surface antigens on the lymphoid cells has been studied. To optimize quantum dots detection we have upgraded fluorescent microscope that allows obtaining multiple images from different quantum dots from one section. Specimens stained with quantum dots remained stable over two weeks and practically did not bleach under mercury lamp illumination during tens of minutes. Direct conjugates of primary mouse monoclonal antibodies with quantum dots demonstrated high specificity and sufficient sensitivity in the case of double staining on the frozen sections. Because of the high stability of quantum dots' fluorescence, this method allows to analyze antigen coexpression on the lymphoid tissue sections for diagnostic purposes. The spillover of fluorescent signals from quantum dots into adjacent fluorescent channels, with maxima differing by 40 nm, did not exceed 8%, which makes the spectral compensation is practically unnecessary.

High-fidelity quantum gates on quantum-dot-confined electron spins in low-Q optical microcavities

NASA Astrophysics Data System (ADS)

Li, Tao; Gao, Jian-Cun; Deng, Fu-Guo; Long, Gui-Lu

2018-04-01

We propose some high-fidelity quantum circuits for quantum computing on electron spins of quantum dots (QD) embedded in low-Q optical microcavities, including the two-qubit controlled-NOT gate and the multiple-target-qubit controlled-NOT gate. The fidelities of both quantum gates can, in principle, be robust to imperfections involved in a practical input-output process of a single photon by converting the infidelity into a heralded error. Furthermore, the influence of two different decay channels is detailed. By decreasing the quality factor of the present microcavity, we can largely increase the efficiencies of these quantum gates while their high fidelities remain unaffected. This proposal also has another advantage regarding its experimental feasibility, in that both quantum gates can work faithfully even when the QD-cavity systems are non-identical, which is of particular importance in current semiconductor QD technology.

Manipulation of nanoscale V-pits to optimize internal quantum efficiency of InGaN multiple quantum wells

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

Chang, Chiao-Yun; Li, Heng; Shih, Yang-Ta

2015-03-02

We systematically investigated the influence of nanoscale V-pits on the internal quantum efficiency (IQE) of InGaN multiple quantum wells (MQWs) by adjusting the underlying superlattices (SLS). The analysis indicated that high barrier energy of sidewall MQWs on V-pits and long diffusion distance between the threading dislocation (TD) center and V-pit boundary were crucial to effectively passivate the non-radiative centers of TDs. For a larger V-pit, the thicker sidewall MQW on V-pit would decrease the barrier energy. On the contrary, a shorter distance between the TD center and V-pit boundary would be observed in a smaller V-pit, which could increase themore » carrier capturing capability of TDs. An optimized V-pit size of approximately 200–250 nm in our experiment could be concluded for MQWs with 15 pairs SLS, which exhibited an IQE value of 70%.« less

Redshift and blueshift of GaNAs/GaAs multiple quantum wells induced by rapid thermal annealing

NASA Astrophysics Data System (ADS)

Sun, Yijun; Cheng, Zhiyuan; Zhou, Qiang; Sun, Ying; Sun, Jiabao; Liu, Yanhua; Wang, Meifang; Cao, Zhen; Ye, Zhi; Xu, Mingsheng; Ding, Yong; Chen, Peng; Heuken, Michael; Egawa, Takashi

2018-02-01

The effects of rapid thermal annealing (RTA) on the optical properties of GaNAs/GaAs multiple quantum wells (MQWs) grown by chemical beam epitaxy (CBE) are studied by photoluminescence (PL) at 77 K. The results show that the optical quality of the MQWs improves significantly after RTA. With increasing RTA temperature, PL peak energy of the MQWs redshifts below 1023 K, while it blueshifts above 1023 K. Two competitive processes which occur simultaneously during RTA result in redshift at low temperature and blueshift at high temperature. It is also found that PL peak energy shift can be explained neither by nitrogen diffusion out of quantum wells nor by nitrogen reorganization inside quantum wells. PL peak energy shift can be quantitatively explained by a modified recombination coupling model in which redshift nonradiative recombination and blueshift nonradiative recombination coexist. The results obtained have significant implication on the growth and RTA of GaNAs material for high performance optoelectronic device application.

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

Yamashita, G.; Nagai, M., E-mail: mnagai@mp.es.osaka-u.ac.jp, E-mail: ashida@mp.es.osaka-u.ac.jp; Ashida, M., E-mail: mnagai@mp.es.osaka-u.ac.jp, E-mail: ashida@mp.es.osaka-u.ac.jp

We estimated the carrier multiplication efficiency in the most common solar-cell material, Si, by using optical-pump/terahertz-probe spectroscopy. Through close analysis of time-resolved data, we extracted the exact number of photoexcited carriers from the sheet carrier density 10 ps after photoexcitation, excluding the influences of spatial diffusion and surface recombination in the time domain. For incident photon energies greater than 4.0 eV, we observed enhanced internal quantum efficiency due to carrier multiplication. The evaluated value of internal quantum efficiency agrees well with the results of photocurrent measurements. This optical method allows us to estimate the carrier multiplication and surface recombination of carriersmore » quantitatively, which are crucial for the design of the solar cells.« less

Command, Control and Integration of Weaponized Unmanned Aircraft into the Air-to-Ground System

DTIC Science & Technology

2007-02-23

munitions. A synthetic aperture radar (SAR) payload is also available for the MQ-1 which allows the system to see through weather and clouds but the...SOF) can pull mensurated or “ sweetened ” coordinates for PGM engagement.70 The ISR deck should be serviced by traditional assets such as F-16s with...Operating Zone RSTA Reconnaissance, Surveillance and Target Acquisition SAR Synthetic Aperture Radar SIAP Standard Integrated Air Picture SDB

Locus Coeruleus, Vigilance and Stress: Brain Mechanisms of Adaptive Behavioral Responsiveness

DTIC Science & Technology

1991-12-14

RroFn r nnrCIMENTATION PAGE AD-A265 724 . .. 1 , ,,IIA-%,NUAL 15 Dec 90 TO 14 Dec 91 mqJ 3OUIIILC 5 FLNONG- LOCUS COERULEUS, VIGILANCE AND STRESS ...the autonomic nervous system (reflected in pupillary diameter), a measure of stress response during the task and a possibly important concomitant of...vigilance performance during normative as well as during stressful conditions. Results of these experiments will open the way to examination of afferents

Mining for Data

NASA Technical Reports Server (NTRS)

1998-01-01

AbTech Corporation used an F-18 HARV (High Alpha Research Vehicle) simulation developed by NASA to create an interactive computer-based prototype of the MQ (Model Quest) SV (System Validator) tool. Dryden Flight Research Center provided support to develop, test, and rapidly reprogram the validation function. AbTech's ModelQuest Enterprises highly automated and outperforms other modeling techniques to quickly discover meaningful relationships, patterns, and trends in databases. Applications include technical and business professionals in finance, marketing, business, banking, retail, healthcare, and aerospace.

Quark-mass dependence of two-nucleon observables

NASA Astrophysics Data System (ADS)

Chen, Jiunn-Wei; Lee, Tze-Kei; Liu, C.-P.; Liu, Yu-Sheng

2012-11-01

We study the potential implications of lattice QCD determinations of the S-wave nucleon-nucleon scattering lengths with unphysical light quark masses. If the light quark masses are small enough such that nuclear effective field theory (NEFT) can be used to perform quark-mass extrapolations, then the leading quark-mass dependence of not only the effective range and the two-body current, but also all the low-energy deuteron matrix elements up to next-to-leading-order in NEFT can be obtained. As a proof of principle, we compute the quark-mass dependence of the deuteron charge radius, magnetic moment, polarizability, and the deuteron photodisintegration cross section using the lattice calculation of the scattering lengths at 354 MeV pion mass by the ``Nuclear Physics with Lattice QCD'' (NPLQCD) collaboration and the NEFT power counting scheme of Beane, Kaplan, and Vuorinen (BKV), even though it is not yet established that the 354 MeV pion mass is within the radius of convergence of the BKV scheme. Once the lattice result with quark mass within the NEFT radius of convergence is obtained, our observation can be used to constrain the time variation of isoscalar combination of u and d quark mass mq, to help the anthropic principle study to find the mq range that allows the existence of life, and to provide a weak test of the multiverse conjecture.

[Anthropometrical profile of Brazilian junior volleyball players for different sports requirement levels].

PubMed

Fonseca-Toledo, Cláudio; Roquetti, Paula; Fernandes-Filho, José

2010-12-01

This study was aimed at investigating the anthropometrics characteristics of male Brazilian junior volleyball players, organised into 3 sports requirement groups: high qualification (HQ) formed by the national team, middle qualification (MQ) formed by athletes playing in the Brazilian national championships and low qualification (LQ) formed by players at school level. 101 athletes were observed, HQ (n=16), MQ (n=68) and LQ (n=17), aged 16.7 ± 0.5; 16.6 ± 0.5 and 16.2 ± 0.7 years, respectively. There following were evaluated: body mass, height, standing reach height, % body fat and Heath & Carter somatotype. The statistical analysis was descriptive and inferential, the Kruskal Wallis test being used for detecting differences between groups (p<0.05 significance) and Spearman correlation coefficient for establishing association between anthropometric characteristics and requirement levels, considering p<0,05 e p<0.01 to be significant and highly significant, respectively. Significant differences (p<0.05) were detected between athlete groups for body mass, height, standing reach height and ectomorphy. A "strong" correlation for height and "regular" correlation for standing reach height, body mass and ectomorphy were observed, according to players' height or classification. The results gave normative data for athletes which will allow coaches and physical instructors to use such information during training as a sports' selection instrument for young talented volleyball players.

Titan's Topside Ionospheric Composition: Cassini Plasma Spectrometer Ion Mass Spectrometer Measurements

NASA Astrophysics Data System (ADS)

Sittler, Edward; Hartle, Richard; Ali, Ashraf; Cooper, John; Lipatov, Alexander; Simpson, David; Sarantos, Menelaos; Chornay, Dennis; Smith, Todd

2017-01-01

We present ion composition measurements of Titan's topside ionosphere using both T9 and T15 Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS) measurements. The IMS is able to make measurements of Titan's ionosphere due to ionospheric outflows as originally reported for the T9 flyby. This allows one to take advantage of the unique capabilities of the CAPS IMS which measures both the mass-per-charge (M/Q) of the ions and the fragments of the ions produced inside the sensor such as carbon, nitrogen and oxygen fragments. Specific attention will be given to such ions as NH4 +, N +, O +, CH4 +, CxHy +, and HCNH + ions as examples. The CAPS IMS uses a time-of-flight (TOF) technique which accelerates ions up to 14.6 kV, so they can pass through ultra-thin carbon foils. Neutral fragments are used to measure the ion M/Q and positive fragments to measure the atomic components. We preliminarily find, by using IMS measurements of T9 and T15 ionospheric outflows, evidence for methane group ions, nitrogen ions, ammonium ions, water group ions and CnHm + ions with n = 2, 3, and 4 within Titan's topside ionosphere. E.C. Sittler acknowledges support at Goddard Space Flight Center by the CAPS Cassini Project from JPL funds under contract # NAS703001TONMO711123/1405851.

On the decay of stratified wake: A numerical study

NASA Astrophysics Data System (ADS)

Chongsiripinyo, Karu; Sarkar, Sutanu

2017-11-01

In stratified fluids, wakes are longer lived with a significant reduction of mean velocity defect. G.R. Spedding (1997) and K.A. Brucker & S. Sarkar (2010) quantify decay rates in 3 phases, namely a near-wake (NW), a non-equilibrium (NEQ), and a quasi-two-dimensional (Q2D) region. Given U0 x-m , where U0 is centerline mean defect velocity and m is a decay rate, both studies observe mNW 2 / 3 , mNEQ 1 / 4 , and mQ 2 D 3 / 4 . Here, U∞, D, and N are the free-stream velocity, length scale of a wake generator, and constant background buoyancy frequency, respectively. However, M. Bonnier and O. Eiff (2002) observe mNEQ = 0.38 in their experiment and K. Chongsiripinyo and S. Sarkar (TSFP10) find mNEQ = 0.4 in their simulation. In the far wake, M. Bonnier and O. Eiff (2002) obtain mQ 2 D = 0.9 close to the value of m = 0.88 from Spedding et al. (1996) at similar flow conditions. Due to the lack of consistency, more evidence is required. The present study utilizes advantages of both body-inclusive (BI) and temporal-model (TF) simulations to not only resolve near-body statistics, but also to reduce computational expense needed. Decay rates of mean velocity defect and turbulence dissipation will be presented.

Efficient quantum computing using coherent photon conversion.

PubMed

Langford, N K; Ramelow, S; Prevedel, R; Munro, W J; Milburn, G J; Zeilinger, A

2011-10-12

Single photons are excellent quantum information carriers: they were used in the earliest demonstrations of entanglement and in the production of the highest-quality entanglement reported so far. However, current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed, single photons, and linear optics gates are inherently probabilistic. Here we introduce a deterministic process--coherent photon conversion (CPC)--that provides a new way to generate and process complex, multiquanta states for photonic quantum information applications. The technique uses classically pumped nonlinearities to induce coherent oscillations between orthogonal states of multiple quantum excitations. One example of CPC, based on a pumped four-wave-mixing interaction, is shown to yield a single, versatile process that provides a full set of photonic quantum processing tools. This set satisfies the DiVincenzo criteria for a scalable quantum computing architecture, including deterministic multiqubit entanglement gates (based on a novel form of photon-photon interaction), high-quality heralded single- and multiphoton states free from higher-order imperfections, and robust, high-efficiency detection. It can also be used to produce heralded multiphoton entanglement, create optically switchable quantum circuits and implement an improved form of down-conversion with reduced higher-order effects. Such tools are valuable building blocks for many quantum-enabled technologies. Finally, using photonic crystal fibres we experimentally demonstrate quantum correlations arising from a four-colour nonlinear process suitable for CPC and use these measurements to study the feasibility of reaching the deterministic regime with current technology. Our scheme, which is based on interacting bosonic fields, is not restricted to optical systems but could also be implemented in optomechanical, electromechanical and superconducting systems with extremely strong intrinsic nonlinearities. Furthermore, exploiting higher-order nonlinearities with multiple pump fields yields a mechanism for multiparty mediation of the complex, coherent dynamics.

Robust Multiple-Range Coherent Quantum State Transfer

PubMed Central

Chen, Bing; Peng, Yan-Dong; Li, Yong; Qian, Xiao-Feng

2016-01-01

We propose a multiple-range quantum communication channel to realize coherent two-way quantum state transport with high fidelity. In our scheme, an information carrier (a qubit) and its remote partner are both adiabatically coupled to the same data bus, i.e., an N-site tight-binding chain that has a single defect at the center. At the weak interaction regime, our system is effectively equivalent to a three level system of which a coherent superposition of the two carrier states constitutes a dark state. The adiabatic coupling allows a well controllable information exchange timing via the dark state between the two carriers. Numerical results show that our scheme is robust and efficient under practically inevitable perturbative defects of the data bus as well as environmental dephasing noise. PMID:27364891

Optical properties and carrier dynamics of GaAs/GaInAs multiple-quantum-well shell grown on GaAs nanowire by molecular beam epitaxy

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

Park, Kwangwook; Ravindran, Sooraj; Ju, Gun Wu

GaAs/GaInAs multiple-quantum-well (MQW) shells having different GaInAs shell width formed on the surface of self-catalyzed GaAs core nanowires (NWs) are grown on (100) Si substrate using molecular beam epitaxy. The photoluminescence emission from GaAs/GaInAs MQW shells and the carrier lifetime could be varied by changing the width of GaInAs shell. Time-resolved photoluminescence measurements showed that the carrier lifetime had a fast and slow decay owing to the mixing of wurtzite and zinc-blende structures of the NWs. Furthermore, strain relaxation caused the carrier lifetime to decrease beyond a certain thickness of GaInAs quantum well shells.

Protected Quantum Computation with Multiple Resonators in Ultrastrong Coupling Circuit QED

NASA Astrophysics Data System (ADS)

Nataf, Pierre; Ciuti, Cristiano

2011-11-01

We investigate theoretically the dynamical behavior of a qubit obtained with the two ground eigenstates of an ultrastrong coupling circuit-QED system consisting of a finite number of Josephson fluxonium atoms inductively coupled to a transmission line resonator. We show a universal set of quantum gates by using multiple transmission line resonators (each resonator represents a single qubit). We discuss the intrinsic “anisotropic” nature of noise sources for fluxonium artificial atoms. Through a master equation treatment with colored noise and many-level dynamics, we prove that, for a general class of anisotropic noise sources, the coherence time of the qubit and the fidelity of the quantum operations can be dramatically improved in an optimal regime of ultrastrong coupling, where the ground state is an entangled photonic “cat” state.

Entanglement of spin waves among four quantum memories.

PubMed

Choi, K S; Goban, A; Papp, S B; van Enk, S J; Kimble, H J

2010-11-18

Quantum networks are composed of quantum nodes that interact coherently through quantum channels, and open a broad frontier of scientific opportunities. For example, a quantum network can serve as a 'web' for connecting quantum processors for computation and communication, or as a 'simulator' allowing investigations of quantum critical phenomena arising from interactions among the nodes mediated by the channels. The physical realization of quantum networks generically requires dynamical systems capable of generating and storing entangled states among multiple quantum memories, and efficiently transferring stored entanglement into quantum channels for distribution across the network. Although such capabilities have been demonstrated for diverse bipartite systems, entangled states have not been achieved for interconnects capable of 'mapping' multipartite entanglement stored in quantum memories to quantum channels. Here we demonstrate measurement-induced entanglement stored in four atomic memories; user-controlled, coherent transfer of the atomic entanglement to four photonic channels; and characterization of the full quadripartite entanglement using quantum uncertainty relations. Our work therefore constitutes an advance in the distribution of multipartite entanglement across quantum networks. We also show that our entanglement verification method is suitable for studying the entanglement order of condensed-matter systems in thermal equilibrium.

CUGatesDensity—Quantum circuit analyser extended to density matrices

NASA Astrophysics Data System (ADS)

Loke, T.; Wang, J. B.

2013-12-01

CUGatesDensity is an extension of the original quantum circuit analyser CUGates (Loke and Wang, 2011) [7] to provide explicit support for the use of density matrices. The new package enables simulation of quantum circuits involving statistical ensemble of mixed quantum states. Such analysis is of vital importance in dealing with quantum decoherence, measurements, noise and error correction, and fault tolerant computation. Several examples involving mixed state quantum computation are presented to illustrate the use of this package. Catalogue identifier: AEPY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEPY_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5368 No. of bytes in distributed program, including test data, etc.: 143994 Distribution format: tar.gz Programming language: Mathematica. Computer: Any computer installed with a copy of Mathematica 6.0 or higher. Operating system: Any system with a copy of Mathematica 6.0 or higher installed. Classification: 4.15. Nature of problem: To simulate arbitrarily complex quantum circuits comprised of single/multiple qubit and qudit quantum gates with mixed state registers. Solution method: A density matrix representation for mixed states and a state vector representation for pure states are used. The construct is based on an irreducible form of matrix decomposition, which allows a highly efficient implementation of general controlled gates with multiple conditionals. Running time: The examples provided in the notebook CUGatesDensity.nb take approximately 30 s to run on a laptop PC.

Quantum origin of quantum jumps: Breaking of unitary symmetry induced by information transfer in the transition from quantum to classical

NASA Astrophysics Data System (ADS)

Zurek, Wojciech Hubert

2007-11-01

Measurements transfer information about a system to the apparatus and then, further on, to observers and (often inadvertently) to the environment. I show that even imperfect copying essential in such situations restricts possible unperturbed outcomes to an orthogonal subset of all possible states of the system, thus breaking the unitary symmetry of its Hilbert space implied by the quantum superposition principle. Preferred outcome states emerge as a result. They provide a framework for “wave-packet collapse,” designating terminal points of quantum jumps and defining the measured observable by specifying its eigenstates. In quantum Darwinism, they are the progenitors of multiple copies spread throughout the environment—the fittest quantum states that not only survive decoherence, but subvert the environment into carrying information about them—into becoming a witness.

Quantum engineering. Confining the state of light to a quantum manifold by engineered two-photon loss.

PubMed

Leghtas, Z; Touzard, S; Pop, I M; Kou, A; Vlastakis, B; Petrenko, A; Sliwa, K M; Narla, A; Shankar, S; Hatridge, M J; Reagor, M; Frunzio, L; Schoelkopf, R J; Mirrahimi, M; Devoret, M H

2015-02-20

Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. We have confined the state of a superconducting resonator to the quantum manifold spanned by two coherent states of opposite phases and have observed a Schrödinger cat state spontaneously squeeze out of vacuum before decaying into a classical mixture. This experiment points toward robustly encoding quantum information in multidimensional steady-state manifolds. Copyright © 2015, American Association for the Advancement of Science.

A review on quantum search algorithms

NASA Astrophysics Data System (ADS)

Giri, Pulak Ranjan; Korepin, Vladimir E.

2017-12-01

The use of superposition of states in quantum computation, known as quantum parallelism, has significant advantage in terms of speed over the classical computation. It is evident from the early invented quantum algorithms such as Deutsch's algorithm, Deutsch-Jozsa algorithm and its variation as Bernstein-Vazirani algorithm, Simon algorithm, Shor's algorithms, etc. Quantum parallelism also significantly speeds up the database search algorithm, which is important in computer science because it comes as a subroutine in many important algorithms. Quantum database search of Grover achieves the task of finding the target element in an unsorted database in a time quadratically faster than the classical computer. We review Grover's quantum search algorithms for a singe and multiple target elements in a database. The partial search algorithm of Grover and Radhakrishnan and its optimization by Korepin called GRK algorithm are also discussed.

Genuine Quantum Signatures in Synchronization of Anharmonic Self-Oscillators.

PubMed

Lörch, Niels; Amitai, Ehud; Nunnenkamp, Andreas; Bruder, Christoph

2016-08-12

We study the synchronization of a Van der Pol self-oscillator with Kerr anharmonicity to an external drive. We demonstrate that the anharmonic, discrete energy spectrum of the quantum oscillator leads to multiple resonances in both phase locking and frequency entrainment not present in the corresponding classical system. Strong driving close to these resonances leads to nonclassical steady-state Wigner distributions. Experimental realizations of these genuine quantum signatures can be implemented with current technology.

Nanometric summation architecture based on optical near-field interaction between quantum dots.

PubMed

Naruse, Makoto; Miyazaki, Tetsuya; Kubota, Fumito; Kawazoe, Tadashi; Kobayashi, Kiyoshi; Sangu, Suguru; Ohtsu, Motoichi

2005-01-15

A nanoscale data summation architecture is proposed and experimentally demonstrated based on the optical near-field interaction between quantum dots. Based on local electromagnetic interactions between a few nanometric elements via optical near fields, we can combine multiple excitations at a certain quantum dot, which allows construction of a summation architecture. Summation plays a key role for content-addressable memory, which is one of the most important functions in optical networks.

Imagery, intuition and imagination in quantum physics education

NASA Astrophysics Data System (ADS)

Stapleton, Andrew J.

2018-03-01

In response to the authors, I demonstrate how threshold concepts offer a means to both contextualise teaching and learning of quantum physics and help transform students into the culture of physics, and as a way to identify particularly troublesome concepts within quantum physics. By drawing parallels from my own doctoral research in another area of contemporary physics—special relativity—I highlight concepts that require an ontological change, namely a shift beyond the reality of everyday Newtonian experience such as time dilation and length contraction, as being troublesome concepts that can present barriers to learning with students often asking "is it real?". Similarly, the domain of quantum physics requires students to move beyond "common sense" perception as it brings into sharp focus the difference between what is experienced via the sense perceptions and the mental abstraction of phenomena. And it's this issue that highlights the important role imagery and creativity have both in quantum physics and in the evolution of physics more generally, and lies in stark contrast to the apparent mathematical focus and lack of opportunity for students to explore ontological issues evident in the authors' research. By reflecting on the authors' observations of a focus on mathematical formalisms and problem solving at the expense of alternative approaches, I explore the dialectic between Heisenberg's highly mathematical approach and Schrödinger's mechanical wave view of the atom, together with its conceptual imagery, at the heart of the evolution of quantum mechanics. In turn, I highlight the significance of imagery, imagination and intuition in quantum physics, together with the importance of adopting an epistemological pluralism—multiple ways of knowing and thinking—in physics education. Again drawing parallels with the authors' work and my own, I identify the role thought experiments have in both quantum physics education and in physics more generally. By introducing the notion of play, I advocate adopting and celebrating multiple approaches of teaching and learning, including thought experiments, play, dialogue and a more conceptual approach inclusive of multiple forms of representation, that complements the current instructional, mathematical approach so as to provide better balance to learning, teaching and the curriculum.

X-ray imaging using avalanche multiplication in amorphous selenium: investigation of intrinsic avalanche noise.

PubMed

Hunt, D C; Tanioka, Kenkichi; Rowlands, J A

2007-12-01

The flat-panel detector (FPD) is the state-of-the-art detector for digital radiography. The FPD can acquire images in real-time, has superior spatial resolution, and is free of the problems of x-ray image intensifiers-veiling glare, pin-cushion and magnetic distortion. However, FPDs suffer from poor signal to noise ratio performance at typical fluoroscopic exposure rates where the quantum noise is reduced to the point that it becomes comparable to the fixed electronic noise. It has been shown previously that avalanche multiplication gain in amorphous selenium (a-Se) can provide the necessary amplification to overcome the electronic noise of the FPD. Avalanche multiplication, however, comes with its own intrinsic contribution to the noise in the form of gain fluctuation noise. In this article a cascaded systems analysis is used to present a modified metric related to the detective quantum efficiency. The modified metric is used to study a diagnostic x-ray imaging system in the presence of intrinsic avalanche multiplication noise independently from other noise sources, such as electronic noise. An indirect conversion imaging system is considered to make the study independent of other avalanche multiplication related noise sources, such as the fluctuations arising from the depth of x-ray absorption. In this case all the avalanche events are initiated at the surface of the avalanche layer, and there are no fluctuations in the depth of absorption. Experiments on an indirect conversion x-ray imaging system using avalanche multiplication in a layer of a-Se are also presented. The cascaded systems analysis shows that intrinsic noise of avalanche multiplication will not have any deleterious influence on detector performance at zero spatial frequency in x-ray imaging provided the product of conversion gain, coupling efficiency, and optical quantum efficiency are much greater than a factor of 2. The experimental results show that avalanche multiplication in a-Se behaves as an intrinsic noise free avalanche multiplication, in accordance with our theory. Provided good coupling efficiency and high optical quantum efficiency are maintained, avalanche multiplication in a-Se has the potential to increase the gain and make negligible contribution to the noise, thereby improving the performance of indirect FPDs in fluoroscopy.

X-ray imaging using avalanche multiplication in amorphous selenium: Investigation of intrinsic avalanche noise

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

Hunt, D. C.; Tanioka, Kenkichi; Rowlands, J. A.

2007-12-15

The flat-panel detector (FPD) is the state-of-the-art detector for digital radiography. The FPD can acquire images in real-time, has superior spatial resolution, and is free of the problems of x-ray image intensifiers--veiling glare, pin-cushion and magnetic distortion. However, FPDs suffer from poor signal to noise ratio performance at typical fluoroscopic exposure rates where the quantum noise is reduced to the point that it becomes comparable to the fixed electronic noise. It has been shown previously that avalanche multiplication gain in amorphous selenium (a-Se) can provide the necessary amplification to overcome the electronic noise of the FPD. Avalanche multiplication, however, comesmore » with its own intrinsic contribution to the noise in the form of gain fluctuation noise. In this article a cascaded systems analysis is used to present a modified metric related to the detective quantum efficiency. The modified metric is used to study a diagnostic x-ray imaging system in the presence of intrinsic avalanche multiplication noise independently from other noise sources, such as electronic noise. An indirect conversion imaging system is considered to make the study independent of other avalanche multiplication related noise sources, such as the fluctuations arising from the depth of x-ray absorption. In this case all the avalanche events are initiated at the surface of the avalanche layer, and there are no fluctuations in the depth of absorption. Experiments on an indirect conversion x-ray imaging system using avalanche multiplication in a layer of a-Se are also presented. The cascaded systems analysis shows that intrinsic noise of avalanche multiplication will not have any deleterious influence on detector performance at zero spatial frequency in x-ray imaging provided the product of conversion gain, coupling efficiency, and optical quantum efficiency are much greater than a factor of 2. The experimental results show that avalanche multiplication in a-Se behaves as an intrinsic noise free avalanche multiplication, in accordance with our theory. Provided good coupling efficiency and high optical quantum efficiency are maintained, avalanche multiplication in a-Se has the potential to increase the gain and make negligible contribution to the noise, thereby improving the performance of indirect FPDs in fluoroscopy.« less

Two-walker discrete-time quantum walks on the line with percolation

NASA Astrophysics Data System (ADS)

Rigovacca, L.; di Franco, C.

2016-02-01

One goal in the quantum-walk research is the exploitation of the intrinsic quantum nature of multiple walkers, in order to achieve the full computational power of the model. Here we study the behaviour of two non-interacting particles performing a quantum walk on the line when the possibility of lattice imperfections, in the form of missing links, is considered. We investigate two regimes, statical and dynamical percolation, that correspond to different time scales for the imperfections evolution with respect to the quantum-walk one. By studying the qualitative behaviour of three two-particle quantities for different probabilities of having missing bonds, we argue that the chosen symmetry under particle-exchange of the input state strongly affects the output of the walk, even in noisy and highly non-ideal regimes. We provide evidence against the possibility of gathering information about the walkers indistinguishability from the observation of bunching phenomena in the output distribution, in all those situations that require a comparison between averaged quantities. Although the spread of the walk is not substantially changed by the addition of a second particle, we show that the presence of multiple walkers can be beneficial for a procedure to estimate the probability of having a broken link.

On the Making of Quantum Chemistry in Germany

NASA Astrophysics Data System (ADS)

Karachalios, Andreas

During the 1990s several historians of science have studied the emergence of quantum chemistry as an autonomous discipline in different national contexts (Nye, 1993; Simões, 1993; Simões, forthcoming; Gavroglu and Simões, 1994; Karachalios, 1997a). Beyond these disciplinary studies, a number of contributions to special aspects of this theme have appeared (Schweber, 1990; Gavroglu, 1995; Simões and Gavroglu, 1997, 1999a,b; Schwarz et al., 1999). In this literature the birth of quantum chemistry has generally been associated with two dates: the 1927 paper of Walter Heitler and Fritz London and the year 1931 in which Linus Pauling and John Clarke Slater independently explained the tetrahedral orientation of the four bonds of the carbon atom. To these dates we might also add a third: in 1928 London published a paper, 'Zur Quantentheorie der homöopolaren Valenzzahlen' (London, 1928), in which he gave a quantum mechanical explanation of the classical chemical notion of valency. There he showed a relationship between the valency numbers and the spectroscopical multiplicity, namely that valency=multiplicity-1. This relation established a bridge between physical and chemical facts. Taken together, these developments constitute important events for the international development of quantum chemistry.

Unified quantum no-go theorems and transforming of quantum pure states in a restricted set

NASA Astrophysics Data System (ADS)

Luo, Ming-Xing; Li, Hui-Ran; Lai, Hong; Wang, Xiaojun

2017-12-01

The linear superposition principle in quantum mechanics is essential for several no-go theorems such as the no-cloning theorem, the no-deleting theorem and the no-superposing theorem. In this paper, we investigate general quantum transformations forbidden or permitted by the superposition principle for various goals. First, we prove a no-encoding theorem that forbids linearly superposing of an unknown pure state and a fixed pure state in Hilbert space of a finite dimension. The new theorem is further extended for multiple copies of an unknown state as input states. These generalized results of the no-encoding theorem include the no-cloning theorem, the no-deleting theorem and the no-superposing theorem as special cases. Second, we provide a unified scheme for presenting perfect and imperfect quantum tasks (cloning and deleting) in a one-shot manner. This scheme may lead to fruitful results that are completely characterized with the linear independence of the representative vectors of input pure states. The upper bounds of the efficiency are also proved. Third, we generalize a recent superposing scheme of unknown states with a fixed overlap into new schemes when multiple copies of an unknown state are as input states.

Highly efficient organic light-emitting diodes with a quantum dot interfacial layer.

PubMed

Ryu, Seung Yoon; Hwang, Byoung Har; Park, Ki Wan; Hwang, Hyeon Seok; Sung, Jin Woo; Baik, Hong Koo; Lee, Chang Ho; Song, Seung Yong; Lee, Jun Yeob

2009-02-11

Advanced organic light-emitting diodes (OLEDs), based on a multiple structure, were achieved in combination with a quantum dot (QD) interfacial layer. The authors used core/shell CdSe/ZnS QDs passivated with trioctylphosphine oxide (TOPO) and TOPO-free QDs as interlayers. Multiple-structure OLEDs (MOLEDs) with TOPO-free QDs showed higher device efficiency because of a well-defined interfacial monolayer formation. Additionally, the three-unit MOLED showed high performance for device efficiency with double-structured QD interfacial layers due to the enhanced charge balance and recombination probability.

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

Damtie, Fikeraddis A., E-mail: Fikeraddis.Damtie@teorfys.lu.se; Wacker, Andreas, E-mail: Andreas.Wacker@fysik.lu.se; Karki, Khadga J., E-mail: Khadga.Karki@chemphys.lu.se

Multiple exciton generation (MEG) is a process in which more than one electron hole pair is generated per absorbed photon. It allows us to increase the efficiency of solar energy harvesting. Experimental studies have shown the multiple exciton generation yield of 1.2 in isolated colloidal quantum dots. However real photoelectric devices require the extraction of electron hole pairs to electric contacts. We provide a systematic study of the corresponding quantum coherent processes including extraction and injection and show that a proper design of extraction and injection rates enhances the yield significantly up to values around 1.6.

Hybrid quantum-classical modeling of quantum dot devices

NASA Astrophysics Data System (ADS)

Kantner, Markus; Mittnenzweig, Markus; Koprucki, Thomas

2017-11-01

The design of electrically driven quantum dot devices for quantum optical applications asks for modeling approaches combining classical device physics with quantum mechanics. We connect the well-established fields of semiclassical semiconductor transport theory and the theory of open quantum systems to meet this requirement. By coupling the van Roosbroeck system with a quantum master equation in Lindblad form, we introduce a new hybrid quantum-classical modeling approach, which provides a comprehensive description of quantum dot devices on multiple scales: it enables the calculation of quantum optical figures of merit and the spatially resolved simulation of the current flow in realistic semiconductor device geometries in a unified way. We construct the interface between both theories in such a way, that the resulting hybrid system obeys the fundamental axioms of (non)equilibrium thermodynamics. We show that our approach guarantees the conservation of charge, consistency with the thermodynamic equilibrium and the second law of thermodynamics. The feasibility of the approach is demonstrated by numerical simulations of an electrically driven single-photon source based on a single quantum dot in the stationary and transient operation regime.

Silicon CMOS architecture for a spin-based quantum computer.

PubMed

Veldhorst, M; Eenink, H G J; Yang, C H; Dzurak, A S

2017-12-15

Recent advances in quantum error correction codes for fault-tolerant quantum computing and physical realizations of high-fidelity qubits in multiple platforms give promise for the construction of a quantum computer based on millions of interacting qubits. However, the classical-quantum interface remains a nascent field of exploration. Here, we propose an architecture for a silicon-based quantum computer processor based on complementary metal-oxide-semiconductor (CMOS) technology. We show how a transistor-based control circuit together with charge-storage electrodes can be used to operate a dense and scalable two-dimensional qubit system. The qubits are defined by the spin state of a single electron confined in quantum dots, coupled via exchange interactions, controlled using a microwave cavity, and measured via gate-based dispersive readout. We implement a spin qubit surface code, showing the prospects for universal quantum computation. We discuss the challenges and focus areas that need to be addressed, providing a path for large-scale quantum computing.

Multi-functional quantum router using hybrid opto-electromechanics

NASA Astrophysics Data System (ADS)

Ma, Peng-Cheng; Yan, Lei-Lei; Chen, Gui-Bin; Li, Xiao-Wei; Liu, Shu-Jing; Zhan, You-Bang

2018-03-01

Quantum routers engineered with multiple frequency bands play a key role in quantum networks. We propose an experimentally accessible scheme for a multi-functional quantum router, using photon-phonon conversion in a hybrid opto-electromechanical system. Our proposed device functions as a bidirectional, tunable multi-channel quantum router, and demonstrates the possibility to route single optical photons bidirectionally and simultaneously to three different output ports, by adjusting the microwave power. Further, the device also behaves as an interswitching unit for microwave and optical photons, yielding probabilistic routing of microwave (optical) signals to optical (microwave) outports. With respect to potential application, we verify the insignificant influence from vacuum and thermal noises in the performance of the router under cryogenic conditions.

Multi-bit dark state memory: Double quantum dot as an electronic quantum memory

NASA Astrophysics Data System (ADS)

Aharon, Eran; Pozner, Roni; Lifshitz, Efrat; Peskin, Uri

2016-12-01

Quantum dot clusters enable the creation of dark states which preserve electrons or holes in a coherent superposition of dot states for a long time. Various quantum logic devices can be envisioned to arise from the possibility of storing such trapped particles for future release on demand. In this work, we consider a double quantum dot memory device, which enables the preservation of a coherent state to be released as multiple classical bits. Our unique device architecture uses an external gating for storing (writing) the coherent state and for retrieving (reading) the classical bits, in addition to exploiting an internal gating effect for the preservation of the coherent state.

Strategies in a symmetric quantum Kolkata restaurant problem

NASA Astrophysics Data System (ADS)

Sharif, Puya; Heydari, Hoshang

2012-12-01

The Quantum Kolkata restaurant problem is a multiple-choice version of the quantum minority game, where a set of n non-communicating players have to chose between one of m choices. A payoff is granted to the players that make a unique choice. It has previously been shown that shared entanglement and quantum operations can aid the players to coordinate their actions and acquire higher payoffs than is possible with classical randomization. In this paper the initial quantum state is expanded to a family of GHZ-type states and strategies are discussed in terms of possible final outcomes. It is shown that the players individually seek outcomes that maximize the collective good.

The Strange (Hi)story of Particles and Waves

NASA Astrophysics Data System (ADS)

Zeh, H. Dieter

2016-03-01

This is an attempt of a non-technical but conceptually consistent presentation of quantum theory in a historical context. While the first part is written for a general readership, Section 5 may appear a bit provocative to some quantum physicists. I argue that the single-particle wave functions of quantum mechanics have to be correctly interpreted as field modes that are "occupied once" (i.e. first excited states of the corresponding quantum oscillators in the case of boson fields). Multiple excitations lead to apparent many-particle wave functions, while the quantum states proper are defined by wave function(al)s on the "configuration" space of fundamental fields, or on another, as yet elusive, fundamental local basis.

Quantum speedup of Monte Carlo methods.

PubMed

Montanaro, Ashley

2015-09-08

Monte Carlo methods use random sampling to estimate numerical quantities which are hard to compute deterministically. One important example is the use in statistical physics of rapidly mixing Markov chains to approximately compute partition functions. In this work, we describe a quantum algorithm which can accelerate Monte Carlo methods in a very general setting. The algorithm estimates the expected output value of an arbitrary randomized or quantum subroutine with bounded variance, achieving a near-quadratic speedup over the best possible classical algorithm. Combining the algorithm with the use of quantum walks gives a quantum speedup of the fastest known classical algorithms with rigorous performance bounds for computing partition functions, which use multiple-stage Markov chain Monte Carlo techniques. The quantum algorithm can also be used to estimate the total variation distance between probability distributions efficiently.

50-GHz-spaced comb of high-dimensional frequency-bin entangled photons from an on-chip silicon nitride microresonator

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

Imany, Poolad; Jaramillo-Villegas, Jose A.; Odele, Ogaga D.

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-binmore » encoded quantum computing, as well as dense quantum key distribution.« less

50-GHz-spaced comb of high-dimensional frequency-bin entangled photons from an on-chip silicon nitride microresonator

DOE PAGES

Imany, Poolad; Jaramillo-Villegas, Jose A.; Odele, Ogaga D.; ...

2018-01-18

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-binmore » encoded quantum computing, as well as dense quantum key distribution.« less

Confining the state of light to a quantum manifold by engineered two-photon loss

NASA Astrophysics Data System (ADS)

Leghtas, Z.; Touzard, S.; Pop, I. M.; Kou, A.; Vlastakis, B.; Petrenko, A.; Sliwa, K. M.; Narla, A.; Shankar, S.; Hatridge, M. J.; Reagor, M.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

2015-02-01

Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. We have confined the state of a superconducting resonator to the quantum manifold spanned by two coherent states of opposite phases and have observed a Schrödinger cat state spontaneously squeeze out of vacuum before decaying into a classical mixture. This experiment points toward robustly encoding quantum information in multidimensional steady-state manifolds.

Quantum speedup of Monte Carlo methods

PubMed Central

Montanaro, Ashley

2015-01-01

Monte Carlo methods use random sampling to estimate numerical quantities which are hard to compute deterministically. One important example is the use in statistical physics of rapidly mixing Markov chains to approximately compute partition functions. In this work, we describe a quantum algorithm which can accelerate Monte Carlo methods in a very general setting. The algorithm estimates the expected output value of an arbitrary randomized or quantum subroutine with bounded variance, achieving a near-quadratic speedup over the best possible classical algorithm. Combining the algorithm with the use of quantum walks gives a quantum speedup of the fastest known classical algorithms with rigorous performance bounds for computing partition functions, which use multiple-stage Markov chain Monte Carlo techniques. The quantum algorithm can also be used to estimate the total variation distance between probability distributions efficiently. PMID:26528079

Novel Approaches to Quantum Computation Using Solid State Qubits

DTIC Science & Technology

2007-12-31

hysteretic DC-SQUIDs, Phys. Rev. B 71, 220509(R) (2005). 18. C.-P. Yang and S. Han, Generation of Greenberger-Horne- Zeilinger entangled states with three SQUID...Horne- Zeilinger entangled states with multiple superconducting quantum interference device qubits/atoms in cavity QED, Phys. Rev. A 70, 062323 (2004

Coherent Control of Diamond Defects for Quantum Information Science and Quantum Sensing

DTIC Science & Technology

2014-04-18

beam steering in micromirror systems [192]. Furthermore, by eliminating require- ments for cryogenic temperatures, our blueprint aims to make the...Isenhower, A. T. Gill, F. P. Lu, M. Saffman, and J. Kim. Independent individual addressing of multiple neutral atom qubits with a micromirror -based

Interfacial relaxation analysis of InGaAs/GaAsP strain-compensated multiple quantum wells and its optical property

NASA Astrophysics Data System (ADS)

Dong, Hailiang; Sun, Jing; Ma, Shufang; Liang, Jian; Jia, Zhigang; Liu, Xuguang; Xu, Bingshe

2018-02-01

InGaAs/GaAsP strain-compensated multiple quantum wells were prepared by metal organic chemical vapor deposition on GaAs (100) substrates with misorientation of 15° toward [111]. In order to obtain better strain-compensated abrupt heterojunction interfaces, the compressive strain and relaxation of different quantum well and the total accumulated strain were investigated by adjusting In composition and the thickness of InxGa1-xAs well and GaAs1-yPy barrier keep constant. High resolution X-ray diffraction results indicate the crystal and interfacial structures of In0.18Ga0.82As (7 nm)/GaAs1-yPy with the least relaxation and total strain mismatch are better than others. From in-situ surface reflectivity curves, we observed the slope of reflectivity curve of multiple quantum wells increases with increasing lattice relaxation. Atomic force microscopic results show surface morphologies of three samples are Volmer-Weber mode. Indium segregation at heterointerface between well and barrier were investigated by secondary ion mass spectrometry which indicate indium diffusion width increase with the increasing total strain mismatch. Finally, a shoulder peak was observed from Gaussian fitting of photoluminescence, stemming from the lattice relaxation. These results demonstrate that the relaxation process is introduced and indium segregation length widens as the relaxation increases. The experimental results will be favorable for optimizing the epitaxial growth of InGaAs/GaAsP strain-compensated quantum wells in order to obtain high quality smooth heterointerface.

A Bowtie Antenna Coupled Tunable Photon-Assisted Tunneling Double Quantum Well (DQW) THz Detector

DTIC Science & Technology

2002-01-01

Proc. Vol. 692 © 2002 Materials Research Society H4.2 A Bowtie Antenna Coupled Tunable Photon-Assisted Tunneling Double Quantum Well (DQW) THz Detector ...on photon-assisted tunneling (PAT) between the two electron layers in a double quantum well (DQW) heterostructure, will be explained. The detector is...the frequency and strength of that radiation. The THz detector discussed in this paper makes use of photon- assisted tunnelling (PAT) between multiple

Experimental Demonstration of a Hybrid-Quantum-Emitter Producing Individual Entangled Photon Pairs in the Telecom Band

PubMed Central

Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can

2016-01-01

Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems. PMID:27225881

Experimental Demonstration of a Hybrid-Quantum-Emitter Producing Individual Entangled Photon Pairs in the Telecom Band.

PubMed

Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can

2016-05-26

Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems.

III-V quantum light source and cavity-QED on silicon.

PubMed

Luxmoore, I J; Toro, R; Del Pozo-Zamudio, O; Wasley, N A; Chekhovich, E A; Sanchez, A M; Beanland, R; Fox, A M; Skolnick, M S; Liu, H Y; Tartakovskii, A I

2013-01-01

Non-classical light sources offer a myriad of possibilities in both fundamental science and commercial applications. Single photons are the most robust carriers of quantum information and can be exploited for linear optics quantum information processing. Scale-up requires miniaturisation of the waveguide circuit and multiple single photon sources. Silicon photonics, driven by the incentive of optical interconnects is a highly promising platform for the passive optical components, but integrated light sources are limited by silicon's indirect band-gap. III-V semiconductor quantum-dots, on the other hand, are proven quantum emitters. Here we demonstrate single-photon emission from quantum-dots coupled to photonic crystal nanocavities fabricated from III-V material grown directly on silicon substrates. The high quality of the III-V material and photonic structures is emphasized by observation of the strong-coupling regime. This work opens-up the advantages of silicon photonics to the integration and scale-up of solid-state quantum optical systems.

Emulating weak localization using a solid-state quantum circuit.

PubMed

Chen, Yu; Roushan, P; Sank, D; Neill, C; Lucero, Erik; Mariantoni, Matteo; Barends, R; Chiaro, B; Kelly, J; Megrant, A; Mutus, J Y; O'Malley, P J J; Vainsencher, A; Wenner, J; White, T C; Yin, Yi; Cleland, A N; Martinis, John M

2014-10-14

Quantum interference is one of the most fundamental physical effects found in nature. Recent advances in quantum computing now employ interference as a fundamental resource for computation and control. Quantum interference also lies at the heart of sophisticated condensed matter phenomena such as Anderson localization, phenomena that are difficult to reproduce in numerical simulations. Here, employing a multiple-element superconducting quantum circuit, with which we manipulate a single microwave photon, we demonstrate that we can emulate the basic effects of weak localization. By engineering the control sequence, we are able to reproduce the well-known negative magnetoresistance of weak localization as well as its temperature dependence. Furthermore, we can use our circuit to continuously tune the level of disorder, a parameter that is not readily accessible in mesoscopic systems. Demonstrating a high level of control, our experiment shows the potential for employing superconducting quantum circuits as emulators for complex quantum phenomena.

Designing Novel Quaternary Quantum Reversible Subtractor Circuits

NASA Astrophysics Data System (ADS)

Haghparast, Majid; Monfared, Asma Taheri

2018-01-01

Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

A Statistical Approach for Determining Subsurface Thermal Structure from Sea Surface Temperature in the Northeast Pacific Ocean.

DTIC Science & Technology

1983-06-01

DE ERMIuIATIC1N OF SUBSUEFACZE THERMAL STRUCTURE * The study of the oceans by satellites has become a sajc: *arena for sc-intific scrutiny and...between *satellite- de ~ived sea surface temperatu-res and vsrt.-cal *temperature profiles, then the areas of acoust-ical oceanicg- raphy and naval...based on dynamical principles and will ulti-mately provide the basis for pred-icting ocear,-c processes. Emp rical mq4thods have been de -termined i n the

Ocean Magnetics: 1. Fundamental Survey and Estimates of Induction Phenomena

DTIC Science & Technology

1977-10-01

sensitivities of /i0-• /Hz only in the far infra - sonic regime. We may note that, for a noise souce at great distances (R) such that its radiation...Various Ocean Depths (D), Pycnocline Depths (d), and Density Changes (6p/p), Sonic Mode (0), with IW Truncated at Brunt-Vaisala Frequency for aJ 25-m...Changes (6p/p), Sonic Mode MQ, with 1WI ~Truncated at Brunt Vaisala Frequency for a 25-rn-Thick Pycnocline.I Dashed line separates quasi-static (left

Performance of the Defense Acquisition System. 2014 Annual Report

DTIC Science & Technology

2014-06-13

for Goods and Services Competition—or at least creating competitive environments—is a central tenet of our Better Buying Power initiatives...percentages despite our stated goals. Various Better Buying Power initiatives have been established to turn this trend around. Table 2-1 provided a...64E New Build JASSM/JASSM-ER MQ-1C Gray Eagle JASSM/JASSM Baseline SBIRS High/Block Buy (GEO 5-6) AIM-9X Blk II JDAM AEHF/AEHF SV 5-6 WIN-T Inc 3 SDB

Tumor Registry Follow-Up at Army Medical Centers.

DTIC Science & Technology

1983-06-03

7a. NAME OF MONITORING ORGANIZATION U.S. AIW-BAYL) R UNIVERSITY (If applicable) GRAD PGM4 IN HEALTH CARE ADMIN HSHA-IHC 6c. ADDRESS (City, State, and...Cancer Program," The Hospital Medical Staff 11, No. 2 (February 1982): 12. 3Charles R . Smart, "The Commission on Cancer," Bulletin, American College of...Mq. 5- a- _ , . . . . - -, uo-----. *_ . . < -% - ’ . ’.- ."-. b-" -" ... ." .. .- r ’° ... V .r’v" - 36 Tumor Registry Letterman Army Medical Center

Radial basis function and its application in tourism management

NASA Astrophysics Data System (ADS)

Hu, Shan-Feng; Zhu, Hong-Bin; Zhao, Lei

2018-05-01

In this work, several applications and the performances of the radial basis function (RBF) are briefly reviewed at first. After that, the binomial function combined with three different RBFs including the multiquadric (MQ), inverse quadric (IQ) and inverse multiquadric (IMQ) distributions are adopted to model the tourism data of Huangshan in China. Simulation results showed that all the models match very well with the sample data. It is found that among the three models, the IMQ-RBF model is more suitable for forecasting the tourist flow.

Pharmacological Protection of the Retina against Damaging Laser Exposures: A Feasibility Study

DTIC Science & Technology

1988-09-01

subsequently administered through this route. Because rabbits can easily be lethally overdosed with barbiturates, surgical plane anesthesia was achieved by...adequately anesthetized. After removal of the second eye, the rabbit was euthanatized by barbiturate overdose . The eye was excised from the rabbit as quickly...Component mq/L uM L-glutamine 73 500 taurine 0.75 6 choline Cl 0.6 4.3 myo-inositol 27 150 Na pyruvate 22 200 ascorbate 18 100 glucose 1800 10,000

Any Time, Every Place: The Networked Societies of War Fighters in a Battlespace of Flows

DTIC Science & Technology

2015-10-01

Power Journal Blair Notes 1. William H. McRaven, Spec Ops: Case Studies in Special Operations Warfare: Theory and Practice (New York: Presidio Press...and Dr. William Thiesen and others, various interviews by the author, US Coast Guard Historian’s Office, Spring 2013. 14. James C. Scott, Seeing... Cullen , “The MQ-9 Reaper Remotely Piloted Aircraft: Humans and Machines in Ac- tion” (PhD diss., Massachusetts Institute of Technology, 2011), 129, 216

Airframe/Propulsion Interference

DTIC Science & Technology

1975-03-01

elancee, en incidence, est prcsenic figure 14. L’intrados se caracterise par une divergence des lignes dc courant, et par une reducti.in ’es nombres...ale de la zone dissipative en R et A/S une fonction du nombre de Hach au recollement Mq et d’un parametre de forme Hiq caracterisant le...extralte d’une Etude expE- rimentale prEsentEe rEf. [13]. Bile se caractErise par un elancement assez important et un rapport de tronoature ft^ /\\M.t

Environmental Assessment for MQ-1 Launch and Recovery Element Training Operations at Southern California Logistics Airport Victorville, California

DTIC Science & Technology

2008-02-01

be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT...LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 176 19a. NAME OF RESPONSIBLE PERSON a . REPORT unclassified b. ABSTRACT...Water Act dBA A -weighted decibel DoD Department of Defense DTSC Department of Toxic Substances Control EA Environmental Assessment EIAP Environmental

Eigenvalue Problems.

DTIC Science & Technology

1987-06-01

Vibration of an Elastic Bar We are interested in studying the small, longitudinal vibra- tions of a longitudinally loaded, elastically supported, elastic...u 2 + + 2u O(( m,Q Uk .(J- MO In the study of eigenvalue problems, central use will be made of Rellich’s theorem (cf. Agmon [19651), which states...H , where a > 0. Sufficient conditions for (4.2) - (4.4) to hold were given in Section 3; cf. (3.15) -(3.17). For the study of (4.1) it is useful to

Demographic Shifts in the United States Air Force: 1994-2007

DTIC Science & Technology

2008-02-15

experience includes F-15C, F-15E, A-10, F-16, RC-135, RQ-4 “Global Hawk”, MQ-9 “Predator” and U-2. He is married to the former Deanna Pacansky of...manpower is relied upon to keep this operational tempo, the retention of personnel in whom the USAF invested heavily through training and equipping will...continue to examine the demographics of both the US and USAF population to be alert to possible changes as they affect recruitment, retention , and

Quantum Gravity in Cyclic (ekpyrotic) and Multiple (anthropic) Universes with Strings And/or Loops

NASA Astrophysics Data System (ADS)

Chung, T. J.

2008-09-01

This paper addresses a hypothetical extension of ekpyrotic and anthropic principles, implying cyclic and multiple universes, respectively. Under these hypotheses, from time immemorial (t = -∞), a universe undergoes a big bang from a singularity, initially expanding and eventually contracting to another singularity (big crunch). This is to prepare for the next big bang, repeating these cycles toward eternity (t = +∞), every 30 billion years apart. Infinity in time backward and forward (t = ±∞) is paralleled with infinity in space (Xi = ±∞), allowing multiple universes to prevail, each undergoing big bangs and big crunches similarly as our own universe. It is postulated that either string theory and /or loop quantum gravity might be able to substantiate these hypotheses.

Vibration-translation energy transfer in anharmonic diatomic molecules. 2: The vibrational quantum number dependence

NASA Technical Reports Server (NTRS)

Mckenzie, R. L.

1975-01-01

A semiclassical model of the inelastic collision between a vibrationally excited anharmonic oscillator and a structureless atom was used to predict the variation of thermally averaged vibration-translation rate coefficients with temperature and initial-state quantum number. Multiple oscillator states were included in a numerical solution for collinear encounters. The results are compared with CO-He experimental values for both ground and excited initial states using several simplified forms of the interaction potential. The numerical model was also used as a basis for evaluating several less complete but analytic models. Two computationally simple analytic approximations were found that successfully reproduced the numerical rate coefficients for a wide range of molecular properties and collision partners. Their limitations were also identified. The relative rates of multiple-quantum transitions from excited states were evaluated for several molecular types.

Optical levitation of a microdroplet containing a single quantum dot

NASA Astrophysics Data System (ADS)

Minowa, Yosuke; Kawai, Ryoichi; Ashida, Masaaki

2015-03-01

We demonstrate the optical levitation or trapping in helium gas of a single quantum dot (QD) within a liquid droplet. Bright single photon emission from the levitated QD in the droplet was observed for more than 200 s. The observed photon count rates are consistent with the value theoretically estimated from the two-photon-action cross section. This paper presents the realization of an optically levitated solid-state quantum emitter. This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: https://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-40-6-906. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.

Electron-electron interaction in Multiple Quantum Wells

NASA Astrophysics Data System (ADS)

Zybert, M.; Marchewka, M.; Tomaka, G.; Sheregii, E. M.

2012-07-01

The complex investigation of the magneto-transport effects in structures containing multiple quantum well (MQWs) based on the GaAs/AlGaAs-heterostructures has been performed. The MQWs investigated have different electron densities in QWs. The parameters of 2DEG in MQWs were determined from the data of the Integer Quantum Hall Effect (IQHE) and Shubnikov-de Haas oscillations (SdH) observed at low temperatures (0.6-4.2 K). The method of calculation of the electron states energies in MQWs has been developed which is based on the splitting of these states due to the exchange interaction (SAS-splitting, see D. Płoch et al., Phys. Rev. B 79 (2009) 195434) including the screening of this interaction. The IQHE and SdH observed in these multilayer structures with the third degree of freedom for electrons are interpreted from this.

Impact of biexcitons on the relaxation mechanisms of polaritons in III-nitride based multiple quantum well microcavities

NASA Astrophysics Data System (ADS)

Corfdir, P.; Levrat, J.; Rossbach, G.; Butté, R.; Feltin, E.; Carlin, J.-F.; Christmann, G.; Lefebvre, P.; Ganière, J.-D.; Grandjean, N.; Deveaud-Plédran, B.

2012-06-01

We report on the direct observation of biexcitons in a III-nitride based multiple quantum well microcavity operating in the strong light-matter coupling regime by means of nonresonant continuous wave and time-resolved photoluminescence at low temperature. First, the biexciton dynamics is investigated for the bare active medium (multiple quantum wells alone) evidencing localization on potential fluctuations due to alloy disorder and thermalization between both localized and free excitonic and biexcitonic populations. Then, the role of biexcitons is considered for the full microcavity: in particular, we observe that for specific detunings the bottom of the lower polariton branch is directly fed by the radiative dissociation of either cavity biexcitons or excitons mediated by one LO-phonon. Accordingly, minimum polariton lasing thresholds are observed, when the bottom of the lower polariton branch corresponds in energy to the exciton or cavity biexciton first LO-phonon replica. This singular observation highlights the role of excitonic molecules in the polariton condensate formation process as being a more efficient relaxation channel when compared to the usually assumed acoustical phonon emission one.

Quantum walks: The first detected passage time problem

NASA Astrophysics Data System (ADS)

Friedman, H.; Kessler, D. A.; Barkai, E.

2017-03-01

Even after decades of research, the problem of first passage time statistics for quantum dynamics remains a challenging topic of fundamental and practical importance. Using a projective measurement approach, with a sampling time τ , we obtain the statistics of first detection events for quantum dynamics on a lattice, with the detector located at the origin. A quantum renewal equation for a first detection wave function, in terms of which the first detection probability can be calculated, is derived. This formula gives the relation between first detection statistics and the solution of the corresponding Schrödinger equation in the absence of measurement. We illustrate our results with tight-binding quantum walk models. We examine a closed system, i.e., a ring, and reveal the intricate influence of the sampling time τ on the statistics of detection, discussing the quantum Zeno effect, half dark states, revivals, and optimal detection. The initial condition modifies the statistics of a quantum walk on a finite ring in surprising ways. In some cases, the average detection time is independent of the sampling time while in others the average exhibits multiple divergences as the sampling time is modified. For an unbounded one-dimensional quantum walk, the probability of first detection decays like (time)(-3 ) with superimposed oscillations, with exceptional behavior when the sampling period τ times the tunneling rate γ is a multiple of π /2 . The amplitude of the power-law decay is suppressed as τ →0 due to the Zeno effect. Our work, an extended version of our previously published paper, predicts rich physical behaviors compared with classical Brownian motion, for which the first passage probability density decays monotonically like (time)-3 /2, as elucidated by Schrödinger in 1915.

Polyad quantum numbers and multiple resonances in anharmonic vibrational studies of polyatomic molecules

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

Krasnoshchekov, Sergey V.; Stepanov, Nikolay F.

2013-11-14

In the theory of anharmonic vibrations of a polyatomic molecule, mixing the zero-order vibrational states due to cubic, quartic and higher-order terms in the potential energy expansion leads to the appearance of more-or-less isolated blocks of states (also called polyads), connected through multiple resonances. Such polyads of states can be characterized by a common secondary integer quantum number. This polyad quantum number is defined as a linear combination of the zero-order vibrational quantum numbers, attributed to normal modes, multiplied by non-negative integer polyad coefficients, which are subject to definition for any particular molecule. According to Kellman's method [J. Chem. Phys.more » 93, 6630 (1990)], the corresponding formalism can be conveniently described using vector algebra. In the present work, a systematic consideration of polyad quantum numbers is given in the framework of the canonical Van Vleck perturbation theory (CVPT) and its numerical-analytic operator implementation for reducing the Hamiltonian to the quasi-diagonal form, earlier developed by the authors. It is shown that CVPT provides a convenient method for the systematic identification of essential resonances and the definition of a polyad quantum number. The method presented is generally suitable for molecules of significant size and complexity, as illustrated by several examples of molecules up to six atoms. The polyad quantum number technique is very useful for assembling comprehensive basis sets for the matrix representation of the Hamiltonian after removal of all non-resonance terms by CVPT. In addition, the classification of anharmonic energy levels according to their polyad quantum numbers provides an additional means for the interpretation of observed vibrational spectra.« less

Frequency-encoded photonic qubits for scalable quantum information processing

DOE PAGES

Lukens, Joseph M.; Lougovski, Pavel

2016-12-21

Among the objectives for large-scale quantum computation is the quantum interconnect: a device that uses photons to interface qubits that otherwise could not interact. However, the current approaches require photons indistinguishable in frequency—a major challenge for systems experiencing different local environments or of different physical compositions altogether. Here, we develop an entirely new platform that actually exploits such frequency mismatch for processing quantum information. Labeled “spectral linear optical quantum computation” (spectral LOQC), our protocol offers favorable linear scaling of optical resources and enjoys an unprecedented degree of parallelism, as an arbitrary Ν-qubit quantum gate may be performed in parallel onmore » multiple Ν-qubit sets in the same linear optical device. Here, not only does spectral LOQC offer new potential for optical interconnects, but it also brings the ubiquitous technology of high-speed fiber optics to bear on photonic quantum information, making wavelength-configurable and robust optical quantum systems within reach.« less

Frequency-encoded photonic qubits for scalable quantum information processing

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

Lukens, Joseph M.; Lougovski, Pavel

Among the objectives for large-scale quantum computation is the quantum interconnect: a device that uses photons to interface qubits that otherwise could not interact. However, the current approaches require photons indistinguishable in frequency—a major challenge for systems experiencing different local environments or of different physical compositions altogether. Here, we develop an entirely new platform that actually exploits such frequency mismatch for processing quantum information. Labeled “spectral linear optical quantum computation” (spectral LOQC), our protocol offers favorable linear scaling of optical resources and enjoys an unprecedented degree of parallelism, as an arbitrary Ν-qubit quantum gate may be performed in parallel onmore » multiple Ν-qubit sets in the same linear optical device. Here, not only does spectral LOQC offer new potential for optical interconnects, but it also brings the ubiquitous technology of high-speed fiber optics to bear on photonic quantum information, making wavelength-configurable and robust optical quantum systems within reach.« less

Quantum chi-squared and goodness of fit testing

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

Temme, Kristan; Verstraete, Frank

2015-01-15

A quantum mechanical hypothesis test is presented for the hypothesis that a certain setup produces a given quantum state. Although the classical and the quantum problems are very much related to each other, the quantum problem is much richer due to the additional optimization over the measurement basis. A goodness of fit test for i.i.d quantum states is developed and a max-min characterization for the optimal measurement is introduced. We find the quantum measurement which leads both to the maximal Pitman and Bahadur efficiencies, and determine the associated divergence rates. We discuss the relationship of the quantum goodness of fitmore » test to the problem of estimating multiple parameters from a density matrix. These problems are found to be closely related and we show that the largest error of an optimal strategy, determined by the smallest eigenvalue of the Fisher information matrix, is given by the divergence rate of the goodness of fit test.« less

Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask.

PubMed

Ji, Qingbin; Li, Lei; Zhang, Wei; Wang, Jia; Liu, Peichi; Xie, Yahong; Yan, Tongxing; Yang, Wei; Chen, Weihua; Hu, Xiaodong

2016-08-24

The existence of high threading dislocation density (TDD) in GaN-based epilayers is a long unsolved problem, which hinders further applications of defect-sensitive GaN-based devices. Multiple-modulation of epitaxial lateral overgrowth (ELOG) is used to achieve high-quality GaN template on a novel serpentine channel patterned sapphire substrate (SCPSS). The dislocation blocking brought by the serpentine channel patterned mask, coupled with repeated dislocation bending, can reduce the dislocation density to a yet-to-be-optimized level of ∼2 × 10(5) to 2 × 10(6) cm(-2). About 80% area utilization rate of GaN with low TDD and stress relaxation is obtained. The periodical variations of dislocation density, optical properties and residual stress in GaN-based epilayers on SCPSS are analyzed. The quantum efficiency of InGaN/GaN multiple quantum wells (MQWs) on it can be increased by 52% compared with the conventional sapphire substrate. The reduced nonradiative recombination centers, the enhanced carrier localization, and the suppressed quantum confined Stark effect, are the main determinants of improved luminous performance in MQWs on SCPSS. This developed ELOG on serpentine shaped mask needs no interruption and regrowth, which can be a promising candidate for the heteroepitaxy of semipolar/nonpolar GaN and GaAs with high quality.

Multiple exciton generation in cluster-free alloy Cd(x)Hg(1-x)Te colloidal quantum dots synthesized in water.

PubMed

Kershaw, Stephen V; Kalytchuk, Sergii; Zhovtiuk, Olga; Shen, Qing; Oshima, Takuya; Yindeesuk, Witoon; Toyoda, Taro; Rogach, Andrey L

2014-12-21

A number of different composition CdxHg1-xTe alloy quantum dots have been synthesized using a modified aqueous synthesis and ion exchange method. The benefits of good stoichiometric control and high emission quantum yield were retained whilst also ensuring that the tendency to form gel-like clusters and adsorb excess cations in the stabilizing ligand shells was mitigated using a sequestering method to remove excess ionic material during and after the synthesis. This was highly desirable for ultrafast carrier dynamics measurements, avoiding strong photocharging effects which may mask fundamental carrier signals. Transient grating measurements revealed a composition dependent carrier multiplication process which competes with phonon mediated carrier cooling to deplete the initial hot carrier population. The interplay between these two mechanisms is strongly dependent on the electron effective mass which in these alloys has a marked composition dependence and may be considerably lower than the hole effective mass. For a composition x = 0.52 we measured a maximum carrier multiplication quantum yield of 199 ± 19% with pump photon energy 3 times the bandgap energy, Eg, whilst the threshold energy is calculated to be just 2.15Eg. There is some evidence to suggest an impact ionization process analogous to the inverse Auger S mechanism seen in bulk CdxHg1-xTe.

In-plane, commensurate GaN/AlN junctions: single-layer composite structures, multiple quantum wells and quantum dots

NASA Astrophysics Data System (ADS)

Durgun, Engin; Onen, Abdullatif; Kecik, Deniz; Ciraci, Salim

In-plane composite structures constructed of the stripes or core/shells of single-layer GaN and AlN, which are joined commensurately display diversity of electronic properties, that can be tuned by the size of their constituents. In heterostructures, the dimensionality of electrons change from 2D to 1D upon their confinements in wide constituent stripes leading to the type-I band alignment and hence multiple quantum well structure in the direct space. The δ-doping of one wide stripe by other narrow stripe results in local narrowing or widening of the band gap. The direct-indirect transition of the fundamental band gap of composite structures can be attained depending on the odd or even values of formula unit in the armchair edged heterojunction. In a patterned array of GaN/AlN core/shells, the dimensionality of the electronic states are reduced from 2D to 0D forming multiple quantum dots in large GaN-cores, while 2D electrons propagate in multiply connected AlN shell as if they are in a supercrystal. These predictions are obtained from first-principles calculations based on density functional theory on single-layer GaN and AlN compound semiconductors which were synthesized recently. This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No 115F088.

Tunable quantum criticality and super-ballistic transport in a "charge" Kondo circuit.

PubMed

Iftikhar, Z; Anthore, A; Mitchell, A K; Parmentier, F D; Gennser, U; Ouerghi, A; Cavanna, A; Mora, C; Simon, P; Pierre, F

2018-05-03

Quantum phase transitions (QPTs) are ubiquitous in strongly-correlated materials. However the microscopic complexity of these systems impedes the quantitative understanding of QPTs. Here, we observe and thoroughly analyze the rich strongly-correlated physics in two profoundly dissimilar regimes of quantum criticality. With a circuit implementing a quantum simulator for the three-channel Kondo model, we reveal the universal scalings toward different low-temperature fixed points and along the multiple crossovers from quantum criticality. Notably, an unanticipated violation of the maximum conductance for ballistic free electrons is uncovered. The present charge pseudospin implementation of a Kondo impurity opens access to a broad variety of strongly-correlated phenomena. Copyright © 2018, American Association for the Advancement of Science.

Toward protocols for quantum-ensured privacy and secure voting

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

Bonanome, Marianna; Buzek, Vladimir; Ziman, Mario

2011-08-15

We present a number of schemes that use quantum mechanics to preserve privacy, in particular, we show that entangled quantum states can be useful in maintaining privacy. We further develop our original proposal [see M. Hillery, M. Ziman, V. Buzek, and M. Bielikova, Phys. Lett. A 349, 75 (2006)] for protecting privacy in voting, and examine its security under certain types of attacks, in particular dishonest voters and external eavesdroppers. A variation of these quantum-based schemes can be used for multiparty function evaluation. We consider functions corresponding to group multiplication of N group elements, with each element chosen by amore » different party. We show how quantum mechanics can be useful in maintaining the privacy of the choices group elements.« less

Modulating emission intensity of GaN-based green light emitting diodes on c-plane sapphire

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

Du, Chunhua; Ma, Ziguang; Zhou, Junming

2014-04-14

The asymmetric dual-wavelength (green/blue) coupled InGaN/GaN multiple quantum wells were proposed to modulate the green emission intensity. Electroluminescent measurements demonstrate the conspicuous increment of the green light intensity by decreasing the coupled barrier thickness. This was partly attributed to capture of more carriers when holes tunnel across the thinner barrier from the blue quantum wells, as a hole reservoir, to the green quantum wells. While lower effective barrier height of the blue quantum wells benefits improved hole transportation from p-GaN to the active region. Efficiency droop of the green quantum wells was partially alleviated due to the enhanced injection efficiencymore » of holes.« less

Quantum-enhanced sensing from hyperentanglement

NASA Astrophysics Data System (ADS)

Walborn, S. P.; Pimentel, A. H.; Davidovich, L.; de Matos Filho, R. L.

2018-01-01

Hyperentanglement—simultaneous entanglement between multiple degrees of freedom of two or more systems—has been used to enhance quantum information tasks such as quantum communication and photonic quantum computing. Here we show that hyperentanglement can lead to increased quantum advantage in metrology, with contributions from the entanglement in each degree of freedom, allowing for Heisenberg scaling in the precision of parameter estimation. Our experiment employs photon pairs entangled in polarization and spatial degrees of freedom to estimate a small tilt angle of a mirror. Precision limits beyond shot noise are saturated through a simple binary measurement of the polarization state. The dynamics considered here have broad applicability, implying that similar strategies based on hyperentanglement can offer improvement in a wide variety of physical scenarios and metrological tasks.

Frustration and quantum criticality

NASA Astrophysics Data System (ADS)

Vojta, Matthias

2018-06-01

This review article is devoted to the interplay between frustrated magnetism and quantum critical phenomena, covering both theoretical concepts and ideas as well as recent experimental developments in correlated-electron materials. The first part deals with local-moment magnetism in Mott insulators and the second part with frustration in metallic systems. In both cases, frustration can either induce exotic phases accompanied by exotic quantum critical points or lead to conventional ordering with unconventional crossover phenomena. In addition, the competition of multiple phases inherent to frustrated systems can lead to multi-criticality.

Optical devices featuring textured semiconductor layers

DOEpatents

Moustakas, Theodore D [Dover, MA; Cabalu, Jasper S [Cary, NC

2011-10-11

A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

Optical devices featuring textured semiconductor layers

DOEpatents

Moustakas, Theodore D [Dover, MA; Cabalu, Jasper S [Cary, NC

2012-08-07

A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

Protecting quantum memories using coherent parity check codes

NASA Astrophysics Data System (ADS)

Roffe, Joschka; Headley, David; Chancellor, Nicholas; Horsman, Dominic; Kendon, Viv

2018-07-01

Coherent parity check (CPC) codes are a new framework for the construction of quantum error correction codes that encode multiple qubits per logical block. CPC codes have a canonical structure involving successive rounds of bit and phase parity checks, supplemented by cross-checks to fix the code distance. In this paper, we provide a detailed introduction to CPC codes using conventional quantum circuit notation. We demonstrate the implementation of a CPC code on real hardware, by designing a [[4, 2, 2

Topical Meeting on Picosecond Electronics and Optoelectronics

DTIC Science & Technology

1987-10-10

Gee, G. D Thurmond, H. W 8-00 AM (Invited Paper) Yen, Hughes Research Laboratories Design and fabrica- FA1 High-Speed Phenomena In GaAs Quantum Wells...D.H. Auston, P.R. Smith, J.C. Bean, J.P. Harbison, and D. Kaplan , "Picosecond Photoconciuctivity in Amorphous Silicon," in Picosecond Phenomena 1980... FA1 -4 QUANTUM-WELL PHYSICS AND DEVICES C. Weisbuch, Thomson CSF, Presider IA 155 , ,Ii : Al-1 High-Speed Phenomena in GaAs Multiple-Quantum-Wells A

Quantum particles in general spacetimes: A tangent bundle formalism

NASA Astrophysics Data System (ADS)

Wohlfarth, Mattias N. R.

2018-06-01

Using tangent bundle geometry we construct an equivalent reformulation of classical field theory on flat spacetimes which simultaneously encodes the perspectives of multiple observers. Its generalization to curved spacetimes realizes a new type of nonminimal coupling of the fields and is shown to admit a canonical quantization procedure. For the resulting quantum theory we demonstrate the emergence of a particle interpretation, fully consistent with general relativistic geometry. The path dependency of parallel transport forces each observer to carry their own quantum state; we find that the communication of the corresponding quantum information may generate extra particles on curved spacetimes. A speculative link between quantum information and spacetime curvature is discussed which might lead to novel explanations for quantum decoherence and vanishing interference in double-slit or interaction-free measurement scenarios, in the mere presence of additional observers.

Quantum origins of objectivity

NASA Astrophysics Data System (ADS)

Horodecki, R.; Korbicz, J. K.; Horodecki, P.

2015-03-01

In spite of all of its successes, quantum mechanics leaves us with a central problem: How does nature create a bridge from fragile quanta to the objective world of everyday experience? Here we find that a basic structure within quantum mechanics that leads to the perceived objectivity is a so-called spectrum broadcast structure. We uncover this based on minimal assumptions, without referring to any dynamical details or a concrete model. More specifically, working formally within the decoherence theory setting with multiple environments (called quantum Darwinism), we show how a crucial for quantum mechanics notion of nondisturbance due to Bohr [N. Bohr, Phys. Rev. 48, 696 (1935), 10.1103/PhysRev.48.696] and a natural definition of objectivity lead to a canonical structure of a quantum system-environment state, reflecting objective information records about the system stored in the environment.

A Quantum Chemistry Concept Inventory for Physical Chemistry Classes

ERIC Educational Resources Information Center

Dick-Perez, Marilu; Luxford, Cynthia J.; Windus, Theresa L.; Holme, Thomas

2016-01-01

A 14-item, multiple-choice diagnostic assessment tool, the quantum chemistry concept inventory or QCCI, is presented. Items were developed based on published student misconceptions and content coverage and then piloted and used in advanced physical chemistry undergraduate courses. In addition to the instrument itself, data from both a pretest,…

Zn1-xCdxSe/ZnSe multiple quantum well photomodulators

NASA Astrophysics Data System (ADS)

Tang, Jiuyao; Kawakami, Yoichi; Fujita, Shizuo; Fujita, Shigeo

1996-10-01

ZnCdSe/ZnSe multiple quantum well (MQW) transmission and reflection photomodulators operating at room temperature were fabricated employing quantum-confined Stark effect on the exciton absorption. Samples were grown on p-type GaAs substrates by MBE with an i-Zn0.87Cd0.13Se/ZnSe MQW heterostructure sandwiched by a ZnSe p-n junction. The transmission modulator was constructed with a Zn0.87Cd0.13Se/ZnSe MQW glued onto a piece of ITO film-covered glass with silver paste and epoxy. To avoid absorption in GaAs substrates, a window with a diameter of about 2 mm was opened using a selective etch. For the reflective use an Al mirror was deposited on the glass back surface, the device then operates in reflection with the light to be modulated making a double pass through the active quantum well region, thereby increasing the modulation amplitude. Measurement results are given in this paper for transmission, reflection, differential transmission, differential absorption, and differential reflection as a function of the incident photon wavelength and the applied field.

Efficient Carrier Multiplication in Colloidal Silicon Nanorods

DOE PAGES

Stolle, Carl Jackson; Lu, Xiaotang; Yu, Yixuan; ...

2017-08-01

In this study, auger recombination lifetimes, absorption cross sections, and the quantum yields of carrier multiplication (CM), or multiexciton generation (MEG), were determined for solvent-dispersed silicon (Si) nanorods using transient absorption spectroscopy (TAS). Nanorods with an average diameter of 7.5 nm and aspect ratios of 6.1, 19.3, and 33.2 were examined. Colloidal Si nanocrystals of similar diameters were also studied for comparison. The nanocrystals and nanorods were passivated with organic ligands by hydrosilylation to prevent surface oxidation and limit the effects of surface trapping of photoexcited carriers. All samples used in the study exhibited relatively efficient photoluminescence. The Auger lifetimesmore » increased with nanorod length, and the nanorods exhibited higher CM quantum yield and efficiency than the nanocrystals with a similar band gap energy E g. Beyond a critical length, the CM quantum yield decreases. Finally, nanorods with the aspect ratio of 19.3 had the highest CM quantum yield of 1.6 ± 0.2 at 2.9E g, which corresponded to a multiexciton yield that was twice as high as observed for the spherical nanocrystals.« less

Multiparameter Estimation in Networked Quantum Sensors

NASA Astrophysics Data System (ADS)

Proctor, Timothy J.; Knott, Paul A.; Dunningham, Jacob A.

2018-02-01

We introduce a general model for a network of quantum sensors, and we use this model to consider the following question: When can entanglement between the sensors, and/or global measurements, enhance the precision with which the network can measure a set of unknown parameters? We rigorously answer this question by presenting precise theorems proving that for a broad class of problems there is, at most, a very limited intrinsic advantage to using entangled states or global measurements. Moreover, for many estimation problems separable states and local measurements are optimal, and can achieve the ultimate quantum limit on the estimation uncertainty. This immediately implies that there are broad conditions under which simultaneous estimation of multiple parameters cannot outperform individual, independent estimations. Our results apply to any situation in which spatially localized sensors are unitarily encoded with independent parameters, such as when estimating multiple linear or nonlinear optical phase shifts in quantum imaging, or when mapping out the spatial profile of an unknown magnetic field. We conclude by showing that entangling the sensors can enhance the estimation precision when the parameters of interest are global properties of the entire network.

Quantum-enhanced spectroscopy with entangled multiphoton states

NASA Astrophysics Data System (ADS)

Dinani, Hossein T.; Gupta, Manish K.; Dowling, Jonathan P.; Berry, Dominic W.

2016-06-01

Traditionally, spectroscopy is performed by examining the position of absorption lines. However, at frequencies near the transition frequency, additional information can be obtained from the phase shift. In this work we consider the information about the transition frequency obtained from both the absorption and the phase shift, as quantified by the Fisher information in an interferometric measurement. We examine the use of multiple single-photon states, NOON states, and numerically optimized states that are entangled and have multiple photons. We find the optimized states that improve over the standard quantum limit set by independent single photons for some atom number densities.

Hierarchical structures consisting of SiO2 nanorods and p-GaN microdomes for efficiently harvesting solar energy for InGaN quantum well photovoltaic cells.

PubMed

Ho, Cheng-Han; Lien, Der-Hsien; Chang, Hung-Chih; Lin, Chin-An; Kang, Chen-Fang; Hsing, Meng-Kai; Lai, Kun-Yu; He, Jr-Hau

2012-12-07

We experimentally and theoretically demonstrated the hierarchical structure of SiO(2) nanorod arrays/p-GaN microdomes as a light harvesting scheme for InGaN-based multiple quantum well solar cells. The combination of nano- and micro-structures leads to increased internal multiple reflection and provides an intermediate refractive index between air and GaN. Cells with the hierarchical structure exhibit improved short-circuit current densities and fill factors, rendering a 1.47 fold efficiency enhancement as compared to planar cells.

Combined atomic force microscopy and photoluminescence imaging to select single InAs/GaAs quantum dots for quantum photonic devices.

PubMed

Sapienza, Luca; Liu, Jin; Song, Jin Dong; Fält, Stefan; Wegscheider, Werner; Badolato, Antonio; Srinivasan, Kartik

2017-07-24

We report on a combined photoluminescence imaging and atomic force microscopy study of single, isolated self-assembled InAs quantum dots. The motivation of this work is to determine an approach that allows to assess single quantum dots as candidates for quantum nanophotonic devices. By combining optical and scanning probe characterization techniques, we find that single quantum dots often appear in the vicinity of comparatively large topographic features. Despite this, the quantum dots generally do not exhibit significant differences in their non-resonantly pumped emission spectra in comparison to quantum dots appearing in defect-free regions, and this behavior is observed across multiple wafers produced in different growth chambers. Such large surface features are nevertheless a detriment to applications in which single quantum dots are embedded within nanofabricated photonic devices: they are likely to cause large spectral shifts in the wavelength of cavity modes designed to resonantly enhance the quantum dot emission, thereby resulting in a nominally perfectly-fabricated single quantum dot device failing to behave in accordance with design. We anticipate that the approach of screening quantum dots not only based on their optical properties, but also their surrounding surface topographies, will be necessary to improve the yield of single quantum dot nanophotonic devices.

Dissipation, dephasing and quantum Darwinism in qubit systems with random unitary interactions

NASA Astrophysics Data System (ADS)

Balaneskovic, Nenad; Mendler, Marc

2016-09-01

We investigate the influence of dissipation and decoherence on quantum Darwinism by generalizing Zurek's original qubit model of decoherence and the establishment of pointer states [W.H. Zurek, Nat. Phys. 5, 181 (2009); see also arXiv: quant-ph/0707.2832v1, pp. 14-19.]. Our model allows for repeated multiple qubit-qubit couplings between system and environment which are described by randomly applied two-qubit quantum operations inducing entanglement, dissipation and dephasing. The resulting stationary qubit states of system and environment are investigated. They exhibit the intricate influence of entanglement generation, dissipation and dephasing on this characteristic quantum phenomenon.

Nano-scale luminescence characterization of individual InGaN/GaN quantum wells stacked in a microcavity using scanning transmission electron microscope cathodoluminescence

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

Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Müller, Marcus; Veit, Peter

2014-07-21

Using cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope at liquid helium temperatures, the optical and structural properties of a 62 InGaN/GaN multiple quantum well embedded in an AlInN/GaN based microcavity are investigated at the nanometer scale. We are able to spatially resolve a spectral redshift between the individual quantum wells towards the surface. Cathodoluminescence spectral linescans allow directly visualizing the critical layer thickness in the quantum well stack resulting in the onset of plastic relaxation of the strained InGaN/GaN system.

Implementation of single-photon quantum routing and decoupling using a nitrogen-vacancy center and a whispering-gallery-mode resonator-waveguide system.

PubMed

Cao, Cong; Duan, Yu-Wen; Chen, Xi; Zhang, Ru; Wang, Tie-Jun; Wang, Chuan

2017-07-24

Quantum router is a key element needed for the construction of future complex quantum networks. However, quantum routing with photons, and its inverse, quantum decoupling, are difficult to implement as photons do not interact, or interact very weakly in nonlinear media. In this paper, we investigate the possibility of implementing photonic quantum routing based on effects in cavity quantum electrodynamics, and present a scheme for single-photon quantum routing controlled by the other photon using a hybrid system consisting of a single nitrogen-vacancy (NV) center coupled with a whispering-gallery-mode resonator-waveguide structure. Different from the cases in which classical information is used to control the path of quantum signals, both the control and signal photons are quantum in our implementation. Compared with the probabilistic quantum routing protocols based on linear optics, our scheme is deterministic and also scalable to multiple photons. We also present a scheme for single-photon quantum decoupling from an initial state with polarization and spatial-mode encoding, which can implement an inverse operation to the quantum routing. We discuss the feasibility of our schemes by considering current or near-future techniques, and show that both the schemes can operate effectively in the bad-cavity regime. We believe that the schemes could be key building blocks for future complex quantum networks and large-scale quantum information processing.

Using time reversal to detect entanglement and spreading of quantum information

NASA Astrophysics Data System (ADS)

Gaerttner, Martin

2017-04-01

Characterizing and understanding the states of interacting quantum systems and their non-equilibrium dynamics is the goal of quantum simulation. For this it is crucial to find experimentally feasible means for quantifying how entanglement and correlation build up and spread. The ability of analog quantum simulators to reverse the unitary dynamics of quantum many-body systems provides new tools in this quest. One such tool is the multiple-quantum coherence (MQC) spectrum previously used in NMR spectroscopy which can now be studied in so far inaccessible parameter regimes near zero temperature in highly controllable environments. I present recent progress in relating the MQC spectrum to established entanglement witnesses such as quantum Fisher information. Recognizing the MQC as out-of-time-order correlation functions, which quantify the spreading, or scrambling, of quantum information, allows us to establish a connection between these quantities and multi-partite entanglement. I will show recent experimental results obtained with a trapped ion quantum simulator and a spinor BEC illustrating the power of time reversal protocols. Supported by: JILA-NSF-PFC-1125844, NSF-PHY-1521080, ARO, AFOSR, AFOSR-MURI, DARPA, NIST.

Satellite-Based Quantum Communications

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

Hughes, Richard J; Nordholt, Jane E; McCabe, Kevin P

2010-09-20

Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secretmore » keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.« less

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

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

Urban, Jeffry Todd

Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics.more » The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.« less

Simultaneous detection of multiple chemical residues in milk using broad-specifity antibodies in a hybrid immunosorbent assay

USDA-ARS?s Scientific Manuscript database

The wide array of applications using quantum dots (QDs) for detection of multiple analytes reflects the versatility of the technology. In this study, a novel immunoassay using 2 types of sensors (QDs and an enzyme) were simultaneously used for detecting multiple structurally different low-molecular...

Timed sequential chemotherapy of cytoxan-refractory multiple myeloma with cytoxan and adriamycin based on induced tumor proliferation.

PubMed

Karp, J E; Humphrey, R L; Burke, P J

1981-03-01

Malignant plasma cell proliferation and induced humoral stimulatory activity (HSA) occur in vivo at a predictable time following drug administration. Sequential sera from 11 patients with poor-risk multiple myeloma (MM) undergoing treatment with Cytoxan (CY) 2400 mq/sq m were assayed for their in vitro effects on malignant bone marrow plasma cell tritiated thymidine (3HTdR) incorporation. Peak HSA was detected day 9 following CY. Sequential changes in marrow malignant plasma cell 3HTdR-labeling indices (LI) paralleled changes in serum activity, with peak LI occurring at the time of peak HS. An in vitro model of chemotherapy demonstrated that malignant plasma cell proliferation was enhanced by HSA, as determined by 3HTdR incorporation assay, 3HTdR LI, and tumor cells counts, and that stimulated plasma cells were more sensitive to cytotoxic effects of adriamycin (ADR) than were cells cultured in autologous pretreatment serum. Based on these studies, we designed a clinical trial to treat 12 CY-refractory poor-risk patients with MM in which ADR (60 mg/sq m) was administered at the time of peak HSA and residual tumor cell LI (day 9) following initial CY, 2400 mg/m (CY1ADR9). Eight of 12 (67%) responded to timed sequential chemotherapy with a greater than 50% decrement in monoclonal protein marker and a median survival projected to be greater than 8 mo duration (range 4-21+ mo). These clinical results using timed sequential CY1ADR9 compare favorably with results obtained using ADR in nonsequential chemotherapeutic regimens.