1,668 research outputs found
Local and non-local approaches to fatigue crack initiation and propogation
Copyright @ 2003 Kulwer Academic Publishers.A functional form of local strength conditions under fatigue loading is introduced and employed to formulation and analysis of fatigue crack initiation and propagation. For the strength conditions associated with the Palmgren-Miner linear damage accumulation rule and the power-type S-N diagram, the problem is reduced to a non-linear integral Volterra equation, which can be transformed to a linear one for the case of a single crack. An analytical solution of some simple problems are presented for the latter case and shortcomings of the local approach are pointed out. A non-local approach free from the shortcomings is presented along with an example of its implementation.This work was completed under the research grant GR/M24592 "Non-local approach to
high cyclic fatigue: Theoretical basis" of the Engineering and Physical Sciences Research Council, UK
Non-alcoholic fatty liver disease: relationship with cardiovascular risk markers and clinical endpoints
Non-alcoholic fatty liver disease (NAFLD) is a common diagnosis and is increasing in prevalence worldwide. NAFLD is usually asymptomatic at presentation; progression of the
disease is unpredictable, leading to the development of a variety of techniques for screening, diagnosis and risk stratification. Clinical methods in current use include serum biomarker panels, hepatic ultrasound, magnetic resonance imaging, and liver biopsy.
NAFLD is strongly associated with the metabolic syndrome, and the most common cause of death for people with the condition is cardiovascular disease. Whether NAFLD is an independent cardiovascular risk factor needs exploration. NAFLD has been associated with surrogate markers of cardiovascular disease such as carotid intima-media thickness, the presence
of carotid plaque, brachial artery vasodilatory responsiveness and CT coronary artery
calcification score.
There is no effective medical treatment for NAFLD and evidence is lacking regarding the efficacy of interventions in mitigating cardiovascular risk. Health care professionals managing patients with NAFLD should tackle the issue with early identification of risk factors and aggressive modification. Current management strategies therefore comprise lifestyle change,with close attention to known cardiovascular risk factors
Optimum Placement of Post-1PN GW Chirp Templates Made Simple at any Match Level via Tanaka-Tagoshi Coordinates
A simple recipe is given for constructing a maximally sparse regular lattice
of spin-free post-1PN gravitational wave chirp templates subject to a given
minimal match constraint, using Tanaka-Tagoshi coordinates.Comment: submitted to Phys. Rev.
The Effective Action in Gauged Supergravity on Hyperbolic Background and Induced Cosmological Constant
The one-loop effective action for 4-dimensional gauged supergravity with
negative cosmological constant, is investigated in space-times with compact
hyperbolic spatial section. The explicit expansion of the effective action as a
power series of the curvature on hyperbolic background is derived, making use
of heat-kernel and zeta-regularization techniques. The induced cosmological and
Newton constants are computed.Comment: 9 pages, UTF 23
Cardinal characteristics at in a small u (κ) model
We provide a model where u(κ)<2κu(κ)<2κ for a supercompact cardinal κ. [10] provides a sketch of how to obtain such a model by modifying the construction in [6]. We provide here a complete proof using a different modification of [6] and further study the values of other natural generalizations of classical cardinal characteristics in our model. For this purpose we generalize some standard facts that hold in the countable case as well as some classical forcing notions and their properties
A Theory for the Conformal Factor in Quantum Gravity
A new theory for the conformal factor in R-gravity is developed. The
infrared phase of this theory, which follows from the one-loop renormalization
group equations for the whole quantum R-gravity theory is described. The
one-loop effective potential for the conformal factor is found explicitly and a
mechanism for inducing Einstein gravity at the minimum of the effective
potential for the conformal factor is suggested. A comparison with the
effective theory of the conformal factor induced by the conformal anomaly, and
also aiming to describe quantum gravity at large distances, is done.Comment: 10 pages, LaTeX file, June 1-199
Indestructibility of Vopenka's Principle
We show that Vopenka's Principle and Vopenka cardinals are indestructible
under reverse Easton forcing iterations of increasingly directed-closed partial
orders, without the need for any preparatory forcing. As a consequence, we are
able to prove the relative consistency of these large cardinal axioms with a
variety of statements known to be independent of ZFC, such as the generalised
continuum hypothesis, the existence of a definable well-order of the universe,
and the existence of morasses at many cardinals.Comment: 15 pages, submitted to Israel Journal of Mathematic
A bound on 6D N=1 supergravities
We prove that there are only finitely many distinct semi-simple gauge groups
and matter representations possible in consistent 6D chiral (1,0) supergravity
theories with one tensor multiplet. The proof relies only on features of the
low-energy theory; the consistency conditions we impose are that anomalies
should be cancelled by the Green-Schwarz mechanism, and that the kinetic terms
for all fields should be positive in some region of moduli space. This result
does not apply to the case of the non-chiral (1,1) supergravities, which are
not constrained by anomaly cancellation.Comment: 23 pages, no figures; two paragraphs added to the proof in Appendix A
covering the SU(2) and SU(3) case, other minor correction
Liver fat in adults with GH deficiency: comparison to matched controls and the effect of GH replacement
CONTEXT:
Existing data regarding the association between growth hormone deficiency (GHD) and liver fat content are conflicting.
OBJECTIVE:
We aimed i) to assess intrahepatocellular lipid (IHCL) content in hypopituitary adults with GHD compared to matched controls and ii) to evaluate the effect of growth hormone (GH) replacement on IHCL content.
DESIGN:
Cross-sectional comparison and controlled intervention study.
PATIENTS, PARTICIPANTS:
Cross-sectional comparison: 22 hypopituitary adults with GHD and 44 healthy controls matched for age, BMI, gender and ethnicity. Intervention study: 9 GHD patients starting GH replacement (GH Rx group), 9 GHD patients not starting replacement therapy (non-GH Rx group).
INTERVENTION:
Intervention study:GH replacement for 6 months in the GH Rx group, dosage was titrated to achieve normal IGF-1 levels.
MAIN OUTCOME MEASURES:
IHCL content determined by proton magnetic resonance spectroscopy (1 H MRS).
RESULTS:
Cross-sectional comparison: There was no difference in IHCL content between GHD patients and healthy controls (1.89% (0.30, 4.03) vs. 1.14% (0.22, 2.32); p=0.2), the prevalence of patients with hepatic steatosis (IHCL of ≥ 5.56%) was similar in the two groups (22.7% vs. 15.9%; chi square probability = 0.4). Intervention study: The change in IHCL content over 6 months did not differ between the GH Rx group and the non-GH Rx group (-0.63 ± 4.53% vs. +0.11 ± 1.46%; p=0.6).
CONCLUSIONS:
In our study liver fat content and the prevalence of hepatic steatosis did not differ between hypopituitary adults with GHD and matched controls. In GHD patients GH replacement had no effect on liver fat content
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