162 research outputs found
Mesonic Wavefunctions in the three-dimensional Gross-Neveu model
We present results from a numerical study of bound state wavefunctions in the
(2+1)-dimensional Gross-Neveu model with staggered lattice fermions at both
zero and nonzero temperature. Mesonic channels with varying quantum numbers are
identified and analysed. In the strongly coupled chirally broken phase at T=0
the wavefunctions expose effects due to varying the interaction strength more
effectively than straightforward spectroscopy. In the weakly coupled chirally
restored phase information on fermion - antifermion scattering is recovered. In
the hot chirally restored phase we find evidence for a screened interaction.
The T=0 chirally symmetric phase is most readily distinguished from the
symmetric phase at high T via the fermion dispersion relation.Comment: 18 page
Critical region of the finite temperature chiral transition
We study a Yukawa theory with spontaneous chiral symmetry breaking and with a
large number N of fermions near the finite temperature phase transition.
Critical properties in such a system can be described by the mean field theory
very close to the transition point. We show that the width of the region where
non-trivial critical behavior sets in is suppressed by a certain power of 1/N.
Our Monte Carlo simulations confirm these analytical results. We discuss
implications for the chiral phase transition in QCD.Comment: 18 page
Critical exponents of the Gross-Neveu model from the effective average action
The phase transition of the Gross-Neveu model with N fermions is investigated
by means of a non-perturbative evolution equation for the scale dependence of
the effective average action. The critical exponents and scaling amplitudes are
calculated for various values of N in d=3. It is also explicitely verified that
the Neveu-Yukawa model belongs to the same universality class as the
Gross-Neveu model.Comment: RevTeX, 4 pages, 2 figures, 1 table. Typos corrected in equation
Current status of clinical outcome measures in inclusion body myositis: a systematised review
OBJECTIVES: Sporadic inclusion body myositis (IBM) is a debilitating idiopathic inflammatory myopathy (IIM) which affects hand function, ambulation, and swallowing. There is no approved pharmacological therapy for IBM, and there is a lack of suitable outcome measure to assess the effect of an intervention. The IBM scientific interest group under IMACS reviewed the previously used outcome measures in IBM clinical studies to lay the path for developing a core set of outcome measures in IBM. METHODS: In this systematised review, we have extracted all outcome measures reported in IBM clinical studies to determine what measures were being used and to assess the need for optimising outcome measures in IBM. RESULTS: We found 13 observational studies, 17 open-label clinical trials, and 15 randomised control trials (RCTs) in IBM. Six-minute walk distance, IBM-functional rating scale (IBM-FRS), quantitative muscle testing, manual muscle testing, maximal voluntary isometric contraction testing, and thigh muscle volume measured by MRI were used as primary outcome measures. Twelve different outcome measures of motor function were used in IBM clinical trials. IBM-FRS was the most used measure of functionality. Swallowing function was reported as a secondary outcome measure in only 3 RCTs. CONCLUSIONS: There are inconsistencies in using outcome measures in clinical studies in IBM. The core set measures developed by the IMACS group for other IIMs are not directly applicable to IBM. As a result, there is an unmet need for an IBM-specific core set of measures to facilitate the evaluation of new potential therapeutics for IBM
Domain wall fermions for planar physics
In 2+1 dimensions, Dirac fermions in reducible, i.e. four-component representations of the spinor algebra form the basis of many interesting model field theories and effective descriptions of condensed matter phenomena. This paper explores lattice formulations which preserve the global U(2N) symmetry present in the massless limit, and its breakdown to U(N)xU(N) implemented by three independent and parity-invariant fermion mass terms. I set out generalisations of the Ginsparg-Wilson relation, leading to a formulation of an overlap operator, and explore the remnants of the global symmetries which depart from the continuum form by terms of order of the lattice spacing. I also define a domain wall formulation in 2+1+1d, and present numerical evidence, in the form of bilinear condensate and meson correlator calculations in quenched non-compact QED using reformulations of all three mass terms, to show that U(2N) symmetry is recovered in the limit that the domain-wall separation L tends to infinity. The possibility that overlap and domain wall formulations of reducible fermions may coincide only in the continuum limit is discussed
The role of emotions on consumers’ satisfaction within the fitness context
Previous studies have suggested that consumption-related emotions are important to understand post-purchase
reactions. This study examines the relationship between fitness consumers’ emotions and overall satisfaction. After an
initial step of free-thought listing and content validity, followed by a pre-test, a survey was conducted among consumers
of five different fitness centers (n=786). The questionnaire included measures to assess positive and negative emotions,
as well as overall satisfaction with the fitness center. The results gathered through a structural equation model provide
evidence that negative emotion experienced by consumers impacts negatively overall satisfaction, while positive emotion
have a positive effect on overall satisfaction. These findings suggest managerial implications, such as the need to collect
consumers’ perceptions of both tangible and intangible aspects of the services, listen costumers’ opinions in a regular
basis, and provide regular training to staff members, in order to identify the triggers of positive emotions and contribute
to increased levels of overall satisfaction. Guidelines for future research within the fitness context are also suggested.Estudos precedentes sugerem
que as emoções relacionadas com o consumo são importantes para compreender as reações dos consumidores após a
compra. Este estudo analisa a relação entre as emoções dos consumidores de fitness e satisfação global. Depois de uma
etapa inicial de listagem de pensamento-livre e validade de conteúdo, seguido de um pré-teste, foi realizada uma pesquisa
entre os consumidores de cinco centros de fitness diferentes (n = 786). O questionário incluiu medidas para avaliar as
emoções positivas e negativas, bem como a satisfação global com o centro de fitness. Os resultados obtidos através de
um modelo de equações estruturais forneceram evidências de que as emoções negativas vivenciadas pelos consumidores
impactam negativamente a satisfação global, enquanto as emoções positivas têm um efeito positivo sobre a satisfação
global. Estes resultados sugerem implicações para os gestores, tais como a necessidade de recolher informação sobre a
perceção dos consumidores dos aspetos tangÃveis e intangÃveis dos serviços, ouvir regularmente as opiniões dos consumidores
e facultar formação regular aos colaboradores. Isto permitirá identificar os aspetos que desencadeiam emoções
positivas e contribuir para o aumento dos nÃveis de satisfação global. Orientações para futuras pesquisas no contexto de
fitness também são sugeridas.Sin financiación0.185 SJR (2015) Q3, 1090/1779 Medicine (miscellaneous); Q4, 177/229 Health (social science), 112/128 Sports scienceUE
Identifying a Window of Vulnerability during Fetal Development in a Maternal Iron Restriction Model
It is well acknowledged from observations in humans that iron deficiency during pregnancy can be associated with a number of developmental problems in the newborn and developing child. Due to the obvious limitations of human studies, the stage during gestation at which maternal iron deficiency causes an apparent impairment in the offspring remains elusive. In order to begin to understand the time window(s) during pregnancy that is/are especially susceptible to suboptimal iron levels, which may result in negative effects on the development of the fetus, we developed a rat model in which we were able to manipulate and monitor the dietary iron intake during specific stages of pregnancy and analyzed the developing fetuses. We established four different dietary-feeding protocols that were designed to render the fetuses iron deficient at different gestational stages. Based on a functional analysis that employed Auditory Brainstem Response measurements, we found that maternal iron restriction initiated prior to conception and during the first trimester were associated with profound changes in the developing fetus compared to iron restriction initiated later in pregnancy. We also showed that the presence of iron deficiency anemia, low body weight, and changes in core body temperature were not defining factors in the establishment of neural impairment in the rodent offspring
Iron Accumulation with Age, Oxidative Stress and Functional Decline
Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects
Self-Objectification Among Physically Active Women
This article discusses self-objectification among physically active women
Spatio-temporal distribution of nitrogen in the undulating littoral zone of Lake Taihu, China
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