261 research outputs found
MP 2009-09
As the price of traditional fossil fuels escalates, there is
increasing interest in using renewable resources, such as
biomass, to meet our energy needs. Biomass resources are of
particular interest to communities in interior Alaska, where
they are abundant (Fresco, 2006). Biomass has the potential
to partially replace heating oil, in addition to being a possible source for electric power generation (Crimp and Adamian, 2000;
Nicholls and Crimp, 2002; Fresco, 2006). The communities of
Tanana and Dot Lake have already installed small Garn boilers to
provide space heating for homes and businesses (Alaska Energy
Authority, 2009). A village-sized combined heat and power
(CHP) demonstration project has been proposed in North Pole.
In addition, several Fairbanks area organizations are interested in
using biomass as a fuel source. For example, the Fairbanks North
Star Borough is interested in using biomass to supplement coal
in a proposed coal-to-liquids project, the Cold Climate Housing
Research Center is planning to test a small biomass fired CHP
unit, and the University of Alaska is planning an upgrade to
its existing coal-fired power plant that could permit co-firing
with biomass fuels. The challenge for all of these projects is in
ensuring that biomass can be harvested on both an economically
and ecologically sustainable basis
Report of ESCOP Subcommittee on Domestic and International Markets and Policy
International Relations/Trade,
General Spectral Flow Formula for Fixed Maximal Domain
We consider a continuous curve of linear elliptic formally self-adjoint
differential operators of first order with smooth coefficients over a compact
Riemannian manifold with boundary together with a continuous curve of global
elliptic boundary value problems. We express the spectral flow of the resulting
continuous family of (unbounded) self-adjoint Fredholm operators in terms of
the Maslov index of two related curves of Lagrangian spaces. One curve is given
by the varying domains, the other by the Cauchy data spaces. We provide
rigorous definitions of the underlying concepts of spectral theory and
symplectic analysis and give a full (and surprisingly short) proof of our
General Spectral Flow Formula for the case of fixed maximal domain. As a side
result, we establish local stability of weak inner unique continuation property
(UCP) and explain its role for parameter dependent spectral theory.Comment: 22 page
Comprehensive vibrational spectroscopic investigation of trans,trans,trans-[Pt(N3)2(OH)2(py)2], a Pt(IV) diazido anticancer prodrug candidate
We report a detailed study of a promising photoactivatable metal-based anticancer prodrug candidate, trans,trans,trans-[Pt(N3)2(OH)2(py)2] (C1; py = pyridine), using vibrational spectroscopic techniques. Attenuated total reflection Fourier transform infrared (ATR-FTIR), Raman, and synchrotron radiation far-IR (SR-FIR) spectroscopies were applied to obtain highly resolved ligand and Pt-ligand vibrations for C1 and its precursors (trans-[Pt(N3)2(py)2] (C2) and trans-[PtCl2(py)2] (C3)). Distinct IR- and Raman-active vibrational modes were assigned with the aid of density functional theory calculations, and trends in the frequency shifts as a function of changing Pt coordination environment were determined and detailed for the first time. The data provide the ligand and Pt-ligand (azide, hydroxide, pyridine) vibrational signatures for C1 in the mid- and far-IR region, which will provide a basis for the better understanding of the interaction of C1 with biomolecules
Personalized Proteome: Comparing Proteogenomics and Open Variant Search Approaches for Single Amino Acid Variant Detection
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Pulse-Echo Quantitative US Biomarkers for Liver Steatosis: Toward Technical Standardization
Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound Biomarker Committee develops methods to measure biomarkers and reduce biomarker variability. In this article, the authors present the clinical need for quantitative imaging biomarkers of liver steatosis, review the current state of various imaging modalities, and describe the technical state of the art for three key liver steatosis pulse-echo quantitative US biomarkers: attenuation coefficient, backscatter coefficient, and speed of sound. Lastly, a perspective on current challenges and recommendations for clinical translation for each biomarker is offered
Intracranial hypertension and cortical thickness in syndromic craniosynostosis
Aim: To evaluate the impact of risk factors for intracranial hypertension (ICH) on cerebral cortex thickness in syndromic craniosynostosis. Method: ICH risk factors including papilloedema, hydrocephalus, obstructive sleep apnea (OSA), cerebellar tonsillar position, occipitofrontal circumference (OFC) curve deflection, age, and sex were collected from the records of patients with syndromic craniosynostosis (Apert, Crouzon, Pfeiffer, Muenke, Saethre-Chotzen syndromes) and imaging. Magnetic resonance images were analysed and exported for statistical analysis. A linear mixed model was developed to determine correlations with cerebral cortex thickness changes. Results: In total, 171 scans from 107 patients (83 males, 88 females, mean age 8y 10mo, range 1y 1mo–34y, SD 5y 9mo) were evaluated. Mean cortical thickness in this cohort was 2.78mm (SD 0.17). Previous findings of papilloedema (p=0.036) and of hydrocephalus (p=0.007) were independently associated with cortical thinning. Cortical thickness did not vary significantly by sex (p=0.534), syndrome (p=0.896), OSA (p=0.464), OFC (p=0.375), or tonsillar position (p=0.682). Interpretation: Detection of papilloedema or hydrocephalus in syndromic craniosynostosis is associated with significant changes in cortical thickness, supporting the need for preventative rather than reactive treatment strategies
Cost-effectiveness of introducing a rotavirus vaccine in developing countries: The case of Mexico
<p>Abstract</p> <p>Background</p> <p>In developing countries rotavirus is the leading cause of severe diarrhoea and diarrhoeal deaths in children under 5. Vaccination could greatly alleviate that burden, but in Mexico as in most low- and middle-income countries the decision to add rotavirus vaccine to the national immunisation program will depend heavily on its cost-effectiveness and affordability. The objective of this study was to assess the cost-effectiveness of including the pentavalent rotavirus vaccine in Mexico's national immunisation program.</p> <p>Methods</p> <p>A cost-effectiveness model was developed from the perspective of the health system, modelling the vaccination of a hypothetical birth cohort of 2 million children monitored from birth through 60 months of age. It compares the cost and disease burden of rotavirus in an unvaccinated cohort of children with one vaccinated as recommended at 2, 4, and 6 months.</p> <p>Results</p> <p>Including the pentavalent vaccine in the national immunisation program could prevent 71,464 medical visits (59%), 5,040 hospital admissions (66%), and 612 deaths from rotavirus gastroenteritis (70%). At US13.70 per 3-dose regimen, vaccination would cost US4,383 per discounted life-year saved, at a total net cost of US15 per dose, the cost per life-year saved is estimated to be lower than one GNP per capita and hence highly cost effective by the WHO Commission on Macroeconomics and Health criteria. The cost-effectiveness estimates are highly dependent upon the mortality in the absence of the vaccine, which suggests that the vaccine is likely to be significantly more cost-effective among poorer populations and among those with less access to prompt medical care – such that poverty reduction programs would be expected to reduce the future cost-effectiveness of the vaccine.</p
The Maslov index in weak symplectic functional analysis
We recall the Chernoff-Marsden definition of weak symplectic structure and
give a rigorous treatment of the functional analysis and geometry of weak
symplectic Banach spaces. We define the Maslov index of a continuous path of
Fredholm pairs of Lagrangian subspaces in continuously varying Banach spaces.
We derive basic properties of this Maslov index and emphasize the new features
appearing.Comment: 34 pages, 13 figures, 45 references, to appear in Ann Glob Anal Geom.
The final publication will be available at http://www.springerlink.com. arXiv
admin note: substantial text overlap with arXiv:math/040613
Time quasi-periodic gravity water waves in finite depth
We prove the existence and the linear stability of Cantor families of small amplitude time quasi-periodic standing water wave solutions\u2014namely periodic and even in the space variable x\u2014of a bi-dimensional ocean with finite depth under the action of pure gravity. Such a result holds for all the values of the depth parameter in a Borel set of asymptotically full measure. This is a small divisor problem. The main difficulties are the fully nonlinear nature of the gravity water waves equations\u2014the highest order x-derivative appears in the nonlinear term but not in the linearization at the origin\u2014and the fact that the linear frequencies grow just in a sublinear way at infinity. We overcome these problems by first reducing the linearized operators, obtained at each approximate quasi-periodic solution along a Nash\u2013Moser iterative scheme, to constant coefficients up to smoothing operators, using pseudo-differential changes of variables that are quasi-periodic in time. Then we apply a KAM reducibility scheme which requires very weak Melnikov non-resonance conditions which lose derivatives both in time and space. Despite the fact that the depth parameter moves the linear frequencies by just exponentially small quantities, we are able to verify such non-resonance conditions for most values of the depth, extending degenerate KAM theory
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