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Search Results: 1 - 10 of 31675 matches for " Thomas Blum "
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Lattice Magnetic Walks
Thomas Blum,Yonathan Shapir
Physics , 1993, DOI: 10.1088/0305-4470/27/2/015
Abstract: Sums of walks for charged particles (e.g. Hofstadter electrons) on a square lattice in the presence of a magnetic field are evaluated. Returning loops are systematically added to directed paths to obtain the unrestricted propagators. Expressions are obtained for special values of the magnetic flux-per-plaquette commensurate with the flux quantum. For commensurate and incommensurate values of the flux, the addition of small returning loops does not affect the general features found earlier for directed paths. Lattice Green's functions are also obtained for staggered flux configurations encountered in models of high-Tc superconductors.
Nucleon structure functions with domain wall fermions
Kostas Orginos,Thomas Blum,Shigemi Ohta
Physics , 2005, DOI: 10.1103/PhysRevD.73.094503
Abstract: We present a quenched lattice QCD calculation of the first few moments of the polarized and un-polarized structure functions of the nucleon. Our calculations are done using domain wall fermions and the DBW2 gauge action with inverse lattice spacing ~1.3GeV, physical volume approximatelly (2.4 fm)^3, and light quark masses down to about 1/4 the strange quark mass. Values of the individual moments are found to be significantly larger than experiment, as in past lattice calculations, but interestingly the chiral symmetry of domain wall fermions allows for a precise determination of the ratio of the flavor non-singlet momentum fraction to the helicity distribution, which is in very good agreement with experiment. We discuss the implications of this result. Next, we show that the chiral symmetry of domain wall fermions is useful in eliminating mixing of power divergent lower dimensional operators with twist-3 operators. Finally, we find the isovector tensor charge at renormalization scale 2 GeV in the MS bar scheme to be 1.192(30), where the error is the statistical error only.
Error reduction technique using covariant approximation and application to nucleon form factor
Thomas Blum,Taku Izubuchi,Eigo Shintani
Physics , 2012,
Abstract: We demonstrate the new class of variance reduction techniques for hadron propagator and nucleon isovector form factor in the realistic lattice of $N_f=2+1$ domain-wall fermion. All-mode averaging (AMA) is one of the powerful tools to reduce the statistical noise effectively for wider varieties of observables compared to existing techniques such as low-mode averaging (LMA). We adopt this technique to hadron two-point functions and three-point functions, and compare with LMA and traditional source-shift method in the same ensembles. We observe AMA is much more cost effective in reducing statistical error for these observables.
A new class of variance reduction techniques using lattice symmetries
Thomas Blum,Taku Izubuchi,Eigo Shintani
Physics , 2012, DOI: 10.1103/PhysRevD.88.094503
Abstract: We present a general class of unbiased improved estimators for physical observables in lattice gauge theory computations which significantly reduces statistical errors at modest computational cost. The error reduction techniques, referred to as covariant approximation averaging, utilize approximations which are covariant under lattice symmetry transformations. We observed cost reductions from the new method compared to the traditional one, for fixed statistical error, of 16 times for the nucleon mass at $M_\pi\sim 330$ MeV (Domain-Wall quark) and 2.6-20 times for the hadronic vacuum polarization at $M_\pi\sim 480$ MeV (Asqtad quark). These cost reductions should improve with decreasing quark mass and increasing lattice sizes.
Hypothesizing “Reward” Gene Polymorphisms May Predict High Rates of Injury and Addiction in the Workforce: A Nutrient and Electrotherapeutic Based Solution  [PDF]
Kenneth Blum, Thomas Simpaatico, Roger L. Waite, Seth H. Blum, Kristina Dushaj, Margaret A. Madigan, Eric R. Braverman, Marlene Oscar-Bermanm
Health (Health) , 2014, DOI: 10.4236/health.2014.616262
Abstract: We hypothesize that individuals with genetic predisposition to Substance Use Disorder (SUD) may have greater likelihood of experiencing work related accidents. We further hypothesize that high risk populations will carry single or multiple polymorphisms associated with brain reward circuitry and/or brain reward cascade, including: Dopaminergic (i.e. DRD2 receptor genes); Serotonergic (i.e. 5-HTT2 receptor genes); Endorphinergic (i.e. pre-enkephalin genes); Gabergic (i.e. GABAA receptor genes); Neurotransmitter Metabolizing genes (i.e. MAO and COMT genes) among others (GARSRXTM). Analgesic addiction as well as “pseudoaddiction” must be treated to improve pain control and its management. We propose that non-pharmacological alternatives to pain relief, in high risk, addiction-prone individuals, are Electrotherapeutic Device(s) and Programs. We further propose patented KB220Z, a nutraceutical designed to release dopamine at the nucleus accumbens, will reduce craving behavior, in genetically programmed individuals. By utilizing both alternatives in DNA analyzed injured workers, a reduction in analgesic addiction (genuine or pseudo) leads to improved health and quicker return to work. We also hypothesize that this novel approach will impact costs related to injuries in the workforce. Effective management of chronic pain, especially in high addiction-prone workforce populations, is possible in spite of being particularly elusive. A series of factors encumber pain assessment and management, including analgesia addiction, pharmacogenomic response to pain medications, and genetically inherited factors involving gene polymorphisms. Additional research is required to test these stipulated hypotheses related to genetic proneness to addiction, but also proneness to accidents in the workplace and reduction of craving behavior. Our hypothesis that genotyping coupled with both KB220ZTM and the pharmaceutical-free Electrotherapy, will reduce iatrogenic induced analgesia addiction. This approach will achieve attainable effective pain management and quicker return to work. We propose outcomes such as the Reward Deficiency System SolutionTM may become an adjunct in the war against iatrogenic pain medication addiction.
Neurogenetic interactions and aberrant behavioral co-morbidity of attention deficit hyperactivity disorder (ADHD): dispelling myths
David E Comings, Thomas JH Chen, Kenneth Blum, Julie F Mengucci, Seth H Blum, Brian Meshkin
Theoretical Biology and Medical Modelling , 2005, DOI: 10.1186/1742-4682-2-50
Abstract: We have reviewed the literature to evaluate some of the claims and counter-claims. The evidence suggests that ADHD is primarily a polygenic disorder involving at least 50 genes, including those encoding enzymes of neurotransmitter metabolism, neurotransmitter transporters and receptors. Because of its polygenic nature, ADHD is often accompanied by other behavioral abnormalities. It is present in adults as well as children, but in itself it does not necessarily impair function in adult life; associated disorders, however, may do so. A range of treatment options is reviewed and the mechanisms responsible for the efficacy of standard drug treatments are considered.The genes so far implicated in ADHD account for only part of the total picture. Identification of the remaining genes and characterization of their interactions is likely to establish ADHD firmly as a biological disorder and to lead to better methods of diagnosis and treatment.ADHD is one of the most well-recognized childhood developmental problems. This condition is characterized by inattention, hyperactivity and impulsiveness. It is now known that these symptoms continue as problems into adulthood for 60% of children with ADHD. That translates into 4% of the US adult population, or 8 million adults. However, few ADHD adults are identified or treated. Adults with ADHD may have difficulty following directions, remembering information, concentrating, organizing tasks or completing work within time limits. If these difficulties are not managed appropriately, they can cause associated behavioral, emotional, social, vocational and academic problems. ADHD afflicts 3% to 7.5% of school-age children [1-4]. An estimated 30% to 70% of those will maintain the disorder into adulthood. Prevalence rates for ADHD in adults are not as well determined as rates for children, but fall in the 1% to 5% range. ADHD affects males at higher rate than females in childhood, but this ratio seems to even out by adulthood.The diagnosis
Composi??o florística e distribui??o altitudinal de epífitas vasculares da Floresta Ombrófila Densa na Serra da Prata, Morretes, Paraná, Brasil
Blum, Christopher Thomas;Roderjan, Carlos Vellozo;Galv?o, Franklin;
Biota Neotropica , 2011, DOI: 10.1590/S1676-06032011000400015
Abstract: the floristic survey of vascular epiphytes was done in the northern part of the prata mountain range (48o 41' 59.39" w and 25o 36' 46.39" s), morretes municipality, comprising 6.3 ha of a slope between 400 and 1,100 m a.s.l., covered by submontane and montane atlantic rainforest. the aims of this study were: 1) characterize the vascular epiphytic flora; 2) discuss the species distribution along the slope and in ecological categories; 3) evaluate the floristic similarity among the study area and other forests of south and southeastern brazil. the present survey was carried out between 2005 and 2010. one hundred twenty phorophytes were climbed and closely examined. two hundred seventy-eight species, 109 genus and 30 families of vascular epiphytes were recorded. pteridophytes comprised 74 species, 30 genus and 10 families. angiosperms comprised 204 species, 79 genus and 20 families. the vascular epiphytic richness was the highest registered in studies of atlantic rainforest in south brazil. seven species were the first records for the paraná state and six are threatened considering the paraná state official list of endangered species. orchidaceae was de richest family, with 103 (37.2%) species and 43 (39.1%) genus, followed by bromeliaceae (38), polypodiaceae (28), hymenophyllaceae (15), araceae (14) and piperaceae (14). the holoepiphytes were the dominant group, comprising 83% of the total. only 54 (19.5%) species were recorded in all altitudinal belts. other 131 (47.3%) species were recorded only under the 700 m a.s.l. and 54 (19.5%) were found just above the 800 m a.s.l. the floristic similarity between the two extremities of the studied slope was low, showing the importance of the altitude for the species distribution. the epiphytic flora of the prata mountain range presented low similarity with others atlantic rainforest communities of paraná and s?o paulo states.
Determination of light quark masses from the electromagnetic splitting of pseudoscalar meson masses computed with two flavors of domain wall fermions
Blum, Thomas;Doi, Takumi;Hayakawa, Masashi;Izubuchi, Taku;Yamada, Norikazu
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.76.114508
Abstract: We determine the light quark masses from lattice QCD simulations incorporating the electromagnetic interaction of valence quarks. The meson masses are calculated on lattice QCD configurations generated by the RBC Collaboration for two flavors of dynamical domain wall fermions, which are combined with QED configurations generated via quenched non-compact lattice QED. The electromagnetic part of the pion mass splitting is found to be $m_{\pi^+}-m_{\pi^0}=4.12(21)$ MeV, where only the statistical error is quoted, and similarly for the kaon, 1.443(55) MeV. Our results for the light quark masses are $m_u^{\rm\bar{MS}}$(2 GeV)=$3.02(27)(19)$ MeV, $m_d^{\rm\bar{MS}}$(2 GeV)=$5.49(20)(34)$ MeV, and $m_s^{\rm\bar{MS}}$(2 GeV)=$119.5(56)(74)$ MeV, where the first error is statistical and the second systematic. By averaging over $\pm e$ to cancel ${\cal O}(e)$ noise exactly on each combined gauge field configuration, we are able to work at physical $\alpha=1/137$ and obtain very small statistical errors. In our calculation, several sources of systematic error remain, including finite volume, non-zero lattice spacing, chiral extrapolation, quenched QED, and quenched strange quark, which may be more significant than the errors quoted above.
Service Requirements-Knowing and Managing the whole End-to-End Service Lifecycle
Abd-El-Kader Sahraoui,Thomas Blum
ARPN Journal of Systems and Software , 2012,
Abstract: There is an ongoing pressure on IT service prices based on efficient and effective processes and IT infrastructure onmarket. The client demands more (web-based)services that are available on-demand from an optimised, and highlyscalable, service provider. For example cloud services especially are not only a technical challenge. They capture the attention of the business and they are the source of growth for the business. Clients and suppliers are searching for the right In-/ Outsourcing level to fulfil these demands. In focus are the business processes and the supporting IT services along the whole supply chain. IT services have also an end-to-end lifecycle with interfaces and different layers (organizations, processes, IT/infrastructure, legal, finance). Existing requirements engineering and management models concentrate only on parts of the IT service requirement lifecycle. There is a need for an end-to-end lifecycle model and the practical management of the IT services. The article regards the definition of service requirements and develops a model for the end-to-end lifecycle management of service requirements and their different layers. The main focus is set on servicerequirement engineering also as basis of Continual Service Improvement and Knowledge Management. Other parts are topic of the current investigation.
February 2013 critical care case of the month: thoracentesis through the looking glass
Singarajah CU,Blum JE,Thomas AR,Luedy H
Southwest Journal of Pulmonary and Critical Care , 2013,
Abstract: No abstract available. Article truncated at 150 words. A 62 year old male was recently diagnosed with Stage 4 squamous cell left lung cancer with metastases to the pleura, brain and mediastinum. He also had known chronic obstructive pulmonary disease (COPD) with a FEV1 = 1.96 L and a known left side pleural effusion (see Figure 1). Figure 1. Baseline chest radiograph showing left pleural effusion (red arrow). He was seen as an outpatient for symptomatic shortness of breath and underwent real time ultrasound guided left sided thoracentesis removing 500 ml of straw-colored fluid. The procedure was uneventful except that near the end, the patient started to cough. He denied any symptoms post procedure apart from some minor puncture site pain. A routine post procedure chest x-ray was performed (Figure 2). Figure 2. Post-thoracentesis x-ray (Panel A) and its negative image (Panel B). What new abnormality is identified on the post-procedure chest x-ray?1.Left pneumothorax2.Right pneumothorax …
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