94 research outputs found
On a Generalization of the Frobenius Number
We consider a generalization of the Frobenius Problem where the object of
interest is the greatest integer which has exactly representations by a
collection of positive relatively prime integers. We prove an analogue of a
theorem of Brauer and Shockley and show how it can be used for computation.Comment: 5 page
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Titanium cholla : lightweight, high-strength structures for aerospace applications.
Aerospace designers seek lightweight, high-strength structures to lower launch weight while creating structures that are capable of withstanding launch loadings. Most 'light-weighting' is done through an expensive, time-consuming, iterative method requiring experience and a repeated design/test/redesign sequence until an adequate solution is obtained. Little successful work has been done in the application of generalized 3D optimization due to the difficulty of analytical solutions, the large computational requirements of computerized solutions, and the inability to manufacture many optimized structures with conventional machining processes. The Titanium Cholla LDRD team set out to create generalized 3D optimization routines, a set of analytically optimized 3D structures for testing the solutions, and a method of manufacturing these complex optimized structures. The team developed two new computer optimization solutions: Advanced Topological Optimization (ATO) and FlexFEM, an optimization package utilizing the eXtended Finite Element Method (XFEM) software for stress analysis. The team also developed several new analytically defined classes of optimized structures. Finally, the team developed a 3D capability for the Laser Engineered Net Shaping{trademark} (LENS{reg_sign}) additive manufacturing process including process planning for 3D optimized structures. This report gives individual examples as well as one generalized example showing the optimized solutions and an optimized metal part
Cost-Effectiveness of Early Versus Standard Antiretroviral Therapy in HIV-Infected Adults in Haiti
This cost-effectiveness study comparing early versus standard antiretroviral treatment (ART) for HIV, based on randomized clinical trial data from Haiti, reveals that the new WHO guidelines for early ART initiation can be cost-effective in resource-poor settings
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ALEGRA : version 4.6.
ALEGRA is an arbitrary Lagrangian-Eulerian multi-material finite element code used for modeling solid dynamics problems involving large distortion and shock propagation. This document describes the basic user input language and instructions for using the software
Does Proximity to Retailers Influence Alcohol and Tobacco Use Among Latino Adolescents?
Despite decades of research surrounding determinants of alcohol and tobacco (A&T) use among adolescents, built environment influences have only recently been explored. This study used ordinal regression on 205 Latino adolescents to explore the influence of the built environment (proximity to A&T retailers) on A&T use, while controlling for recognized social predictors. The sample was 45% foreign-born. A&T use was associated with distance from respondents’ home to the nearest A&T retailer (−), acculturation (+), parents’ consistent use of contingency management (−), peer use of A&T (+), skipping school (+), attending school in immediate proximity to the US/Mexico border (+), and the interaction between the distance to the nearest retailer and parents’ consistent use of contingency management (+). The association between decreasing distance to the nearest A&T retailer and increased A&T use in Latino adolescents reveals an additional risk behavior determinant in the US–Mexico border region
Intended Consequences Statement in Conservation Science and Practice
As the biodiversity crisis accelerates, the stakes are higher for threatened plants and animals. Rebuilding the health of our planet will require addressing underlying threats at many scales, including habitat loss and climate change. Conservation interventions such as habitat protection, management, restoration, predator control, trans location, genetic rescue, and biological control have the potential to help threatened or endangered species avert extinction. These existing, well-tested methods can be complemented and augmented by more frequent and faster adoption of new technologies, such as powerful new genetic tools. In addition, synthetic biology might offer solutions to currently intractable conservation problems. We believe that conservation needs to be bold and clear-eyed in this moment of great urgency
A Novel Role for Mc1r in the Parallel Evolution of Depigmentation in Independent Populations of the Cavefish Astyanax mexicanus
The evolution of degenerate characteristics remains a poorly understood phenomenon. Only recently has the identification of mutations underlying regressive phenotypes become accessible through the use of genetic analyses. Focusing on the Mexican cave tetra Astyanax mexicanus, we describe, here, an analysis of the brown mutation, which was first described in the literature nearly 40 years ago. This phenotype causes reduced melanin content, decreased melanophore number, and brownish eyes in convergent cave forms of A. mexicanus. Crosses demonstrate non-complementation of the brown phenotype in F2 individuals derived from two independent cave populations: Pachón and the linked Yerbaniz and Japonés caves, indicating the same locus is responsible for reduced pigmentation in these fish. While the brown mutant phenotype arose prior to the fixation of albinism in Pachón cave individuals, it is unclear whether the brown mutation arose before or after the fixation of albinism in the linked Yerbaniz/Japonés caves. Using a QTL approach combined with sequence and functional analyses, we have discovered that two distinct genetic alterations in the coding sequence of the gene Mc1r cause reduced pigmentation associated with the brown mutant phenotype in these caves. Our analysis identifies a novel role for Mc1r in the evolution of degenerative phenotypes in blind Mexican cavefish. Further, the brown phenotype has arisen independently in geographically separate caves, mediated through different mutations of the same gene. This example of parallelism indicates that certain genes are frequent targets of mutation in the repeated evolution of regressive phenotypes in cave-adapted species
Spatially restricted drivers and transitional cell populations cooperate with the microenvironment in untreated and chemo-resistant pancreatic cancer
Pancreatic ductal adenocarcinoma is a lethal disease with limited treatment options and poor survival. We studied 83 spatial samples from 31 patients (11 treatment-naïve and 20 treated) using single-cell/nucleus RNA sequencing, bulk-proteogenomics, spatial transcriptomics and cellular imaging. Subpopulations of tumor cells exhibited signatures of proliferation, KRAS signaling, cell stress and epithelial-to-mesenchymal transition. Mapping mutations and copy number events distinguished tumor populations from normal and transitional cells, including acinar-to-ductal metaplasia and pancreatic intraepithelial neoplasia. Pathology-assisted deconvolution of spatial transcriptomic data identified tumor and transitional subpopulations with distinct histological features. We showed coordinated expression of TIGIT in exhausted and regulatory T cells and Nectin in tumor cells. Chemo-resistant samples contain a threefold enrichment of inflammatory cancer-associated fibroblasts that upregulate metallothioneins. Our study reveals a deeper understanding of the intricate substructure of pancreatic ductal adenocarcinoma tumors that could help improve therapy for patients with this disease
Assessment of gene-by-sex interaction effect on bone mineral density
To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Sexual dimorphism in various bone phenotypes, including bone mineral density (BMD), is widely observed; however, the extent to which genes explain these sex differences is unclear. To identify variants with different effects by sex, we examined gene-by-sex autosomal interactions genome-wide, and performed expression quantitative trait loci (eQTL) analysis and bioinformatics network analysis. We conducted an autosomal genome-wide meta-analysis of gene-by-sex interaction on lumbar spine (LS) and femoral neck (FN) BMD in 25,353 individuals from 8 cohorts. In a second stage, we followed up the 12 top single-nucleotide polymorphisms (SNPs; p < 1 × 10(-5) ) in an additional set of 24,763 individuals. Gene-by-sex interaction and sex-specific effects were examined in these 12 SNPs. We detected one novel genome-wide significant interaction associated with LS-BMD at the Chr3p26.1-p25.1 locus, near the GRM7 gene (male effect = 0.02 and p = 3.0 × 10(-5) ; female effect = -0.007 and p = 3.3 × 10(-2) ), and 11 suggestive loci associated with either FN- or LS-BMD in discovery cohorts. However, there was no evidence for genome-wide significant (p < 5 × 10(-8) ) gene-by-sex interaction in the joint analysis of discovery and replication cohorts. Despite the large collaborative effort, no genome-wide significant evidence for gene-by-sex interaction was found to influence BMD variation in this screen of autosomal markers. If they exist, gene-by-sex interactions for BMD probably have weak effects, accounting for less than 0.08% of the variation in these traits per implicated SNP. © 2012 American Society for Bone and Mineral Research.Medtronic
NIH R01 AG18728
R01HL088119
R01AR046838
U01 HL084756
R01 AR43351
P01-HL45522
R01-MH-078111
R01-MH-083824
Nutrition and Obesity Research Center of Maryland P30DK072488
NIAMS/NIH F32AR059469
Instituto de Salud Carlos III-FIS (Spanish Health Ministry) PI 06/0034
PI08/0183
Canadian Institutes of Health Research (CIHR)
NHLBI HHSN268201200036C
N01-HC-85239
N01-HC-85079
N01-HC-85086
N01-HC-35129
N01 HC15103
N01 HC-55222
N01-HC-75150
N01-HC-45133
HL080295
HL087652
HL105756
NIA AG-023629
AG-15928
AG-20098
AG-027058
N01AG62101
N01AG62103
N01AG62106
1R01AG032098-01A1
National Center of Advancing Translational Technologies CTSI UL1TR000124
National Institute of Diabetes and Digestive and Kidney Diseases DK063491
EUROSPAN (European Special Populations Research Network)
European Commission FP6 STRP grant 018947
LSHG-CT-2006-01947
Netherlands Organisation for Scientific Research
Erasmus MC
Centre for Medical Systems Biology (CMSB)
Netherlands Brain Foundation (HersenStichting Nederland)
US National Institute for Arthritis, Musculoskeletal and Skin Diseases
National Institute on Aging R01 AR/AG41398
R01 AR050066
R21 AR056405
National Heart, Lung, and Blood Institute's Framingham Heart Study N01-HC-25195
Affymetrix, Inc. N02-HL-6-4278
Canadian Institutes of Health Research from Institute of Aging 165446
Institute of Genetics 179433
Institute of Musculoskeletal health 221765
Intramural Research Program of the NIH, National Institute on Aging
National Institutes of Health HHSN268200782096C
Hong Kong Research Grant Council HKU 768610M
Bone Health Fund of HKU Foundation
KC Wong Education Foundation
Small Project Funding 201007176237
Matching Grant
CRCG Grant
Osteoporosis and Endocrine Research Fund
Genomics Strategic Research Theme of The University of Hong Kong
Netherlands Organisation of Scientific Research NWO Investments 175.010.2005.011
911-03-012
Research Institute for Diseases in the Elderly 014-93-015
Netherlands Genomics Initiative (NGI)/Netherlands Consortium for Healthy Aging (NCHA) 050-060-810
Erasmus Medical Center and Erasmus University, Rotterdam
Netherlands Organization for the Health Research and Development (ZonMw)
Research Institute for Diseases in the Elderly (RIDE)
Ministry of Education, Culture and Science
Ministry for Health, Welfare and Sports
European Commission (DG XII)
Municipality of Rotterdam
German Bundesministerium fur Forschung und Technology 01 AK 803 A-H
01 IG 07015
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