582 research outputs found
Satisfying due-dates in the presence of sequence dependent family setups with a special comedown structure
Cataloged from PDF version of article.This paper addresses a static, n-job, single-machine scheduling problem with sequence dependent family setups. The
setup matrix follows a special structure where a constant setup is required only if a job from a smaller indexed family
is an immediate successor of one from a larger indexed family. The objective is to minimize the maximum lateness (Lmax).
A two-step neighborhood search procedure and an implicit enumeration scheme are proposed. Both procedures exploit the
problem structure. The enumeration scheme produces optimum solutions to small and medium sized problems in
reasonable computational times, yet it fails to perform efficiently in larger instances. Computational results show that
the heuristic procedure is highly effective, and is efficient even for extremely large problems.
2006 Elsevier Ltd. All rights reserved
Redesigning Large-Scale Multimodal Transit Networks with Shared Autonomous Mobility Services
Public transit systems have faced challenges and opportunities from emerging
Shared Autonomous Mobility Services (SAMS). This study addresses a city-scale
multimodal transit network design problem, with shared autonomous vehicles as
both transit feeders and a direct interzonal mode. The framework captures
spatial demand and modal characteristics, considers intermodal transfers and
express services, determines transit infrastructure investment and path flows,
and designs transit routes. A system-optimal multimodal transit network is
designed with minimum total door-to-door generalized costs of users and
operators, while satisfying existing transit origin-destination demand within a
pre-set infrastructure budget. Firstly, the geography, demand, and modes in
each clustered zone are characterized with continuous approximation. Afterward,
the decisions of network link investment and multimodal path flows in zonal
connection optimization are formulated as a minimum-cost multi-commodity
network flow (MCNF) problem and solved efficiently with a mixed-integer linear
programming (MILP) solver. Subsequently, the route generation problem is solved
by expanding the MCNF formulation to minimize intramodal transfers. To
demonstrate the framework efficiency, this study uses transit demand from the
Chicago metropolitan area to redesign a multimodal transit network. The
computational results present savings in travelers' journey time and operators'
costs, demonstrating the potential benefits of collaboration between multimodal
transit systems and SAMS.Comment: 44 pages, 15 figures, under review for the 25th International
Symposium on Transportation and Traffic Theory (ISTTT25
Evaluation of Agricultural Machinery Presence and Usage Activities in Tokat
In this study, the area of influence of agricultural machinery in Tokat, its districts and the size of the cultivated area were compared. Required number of machineries was evaluated. Thus, the machines were divided into seven groups (Soil Tillage Machinery, Sowing and Planting Machinery, Maintenance and Fertilization Machinery, Plant Protection Machinery, Harvesting Machinery, Combine Harvester, Tractors). Data on the number of cultivated areas and agricultural machinery were taken from the Turkish Statistical Institute. The number of machines, daily working time, annual workable days, effective working capacity, and machine impact area for each machine were calculated separately. Based on this data, the number of machines that should be in each district was determined. As a result, it was determined that the number of Subsoiler, Combi Harrow, Stone Collecting Machinery, Rotary Cultivator, Soil levelling Machinery, Rotary Tiller, Seedling Planting Machinery, Arc Opening Plough, Manure Spreading Machinery, Baler, and Combine Harvester is insufficient in the province of Tokat. It was determined that other machines in the groups were more than necessary. Baler had the highest deficit, while tractor had the highest surplus. The importance of planning in enterprises and the machines that should be prioritized in the production of industrialists have been revealed
Landau Expansion for the Kugel-Khomskii Hamiltonian
The Kugel-Khomskii (KK) Hamiltonian for the titanates describes spin and
orbital superexchange interactions between ions in an ideal perovskite
structure in which the three orbitals are degenerate in energy and
electron hopping is constrained by cubic site symmetry. In this paper we
implement a variational approach to mean-field theory in which each site, ,
has its own single-site density matrix \rhov(i), where , the
number of allowed single-particle states, is 6 (3 orbital times 2 spin states).
The variational free energy from this 35 parameter density matrix is shown to
exhibit the unusual symmetries noted previously which lead to a
wavevector-dependent susceptibility for spins in orbitals which is
dispersionless in the -direction. Thus, for the cubic KK model
itself, mean-field theory does not provide wavevector `selection', in agreement
with rigorous symmetry arguments. We consider the effect of including various
perturbations. When spin-orbit interactions are introduced, the susceptibility
has dispersion in all directions in -space, but the resulting
antiferromagnetic mean-field state is degenerate with respect to global
rotation of the staggered spin, implying that the spin-wave spectrum is
gapless. This possibly surprising conclusion is also consistent with rigorous
symmetry arguments. When next-nearest-neighbor hopping is included, staggered
moments of all orbitals appear, but the sum of these moments is zero, yielding
an exotic state with long-range order without long-range spin order. The effect
of a Hund's rule coupling of sufficient strength is to produce a state with
orbital order.Comment: 20 pages, 5 figures, submitted to Phys. Rev. B (2003
Water-stable zirconium-based metal-organic framework material with high-surface area and gas-storage capacities.
We designed, synthesized, and characterized a new Zr-based metal-organic framework material, NU-1100, with a pore volume of 1.53 ccg(-1) and Brunauer-Emmett-Teller (BET) surface area of 4020 m(2) g(-1) ; to our knowledge, currently the highest published for Zr-based MOFs. CH4 /CO2 /H2 adsorption isotherms were obtained over a broad range of pressures and temperatures and are in excellent agreement with the computational predictions. The total hydrogen adsorption at 65 bar and 77 K is 0.092 g g(-1) , which corresponds to 43 g L(-1) . The volumetric and gravimetric methane-storage capacities at 65 bar and 298 K are approximately 180 vSTP /v and 0.27 g g(-1) , respectively.OKF, JTH and RQS thank DOE ARPA-E and the Stanford Global Climate and Energy Project for support of work relevant to methane and CO2, respectively. TY acknowledges support by the U. S. Department of Energy through BES Grant No. DE-FG02-08ER46522. WB acknowledges support from the Foundation for Polish Science through the “Kolumb” Program. DFJ acknowledges the Royal Society (UK) for a University Research Fellowship. This material is based upon work supported by the National Science Foundation (grant CHE-1048773).This is the accepted manuscript. The final version is available as 'Water-Stable Zirconium-Based Metal–Organic Framework Material with High-Surface Area and Gas-Storage Capacities' from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/chem.201402895/abstract
Data sharing and ontology use among agricultural genetics, genomics, and breeding databases and resources of the AgBioData Consortium
Over the last several decades, there has been rapid growth in the number and
scope of agricultural genetics, genomics and breeding (GGB) databases and
resources. The AgBioData Consortium (https://www.agbiodata.org/) currently
represents 44 databases and resources covering model or crop plant and animal
GGB data, ontologies, pathways, genetic variation and breeding platforms
(referred to as 'databases' throughout). One of the goals of the Consortium is
to facilitate FAIR (Findable, Accessible, Interoperable, and Reusable) data
management and the integration of datasets which requires data sharing, along
with structured vocabularies and/or ontologies. Two AgBioData working groups,
focused on Data Sharing and Ontologies, conducted a survey to assess the status
and future needs of the members in those areas. A total of 33 researchers
responded to the survey, representing 37 databases. Results suggest that data
sharing practices by AgBioData databases are in a healthy state, but it is not
clear whether this is true for all metadata and data types across all
databases; and that ontology use has not substantially changed since a similar
survey was conducted in 2017. We recommend 1) providing training for database
personnel in specific data sharing techniques, as well as in ontology use; 2)
further study on what metadata is shared, and how well it is shared among
databases; 3) promoting an understanding of data sharing and ontologies in the
stakeholder community; 4) improving data sharing and ontologies for specific
phenotypic data types and formats; and 5) lowering specific barriers to data
sharing and ontology use, by identifying sustainability solutions, and the
identification, promotion, or development of data standards. Combined, these
improvements are likely to help AgBioData databases increase development
efforts towards improved ontology use, and data sharing via programmatic means.Comment: 17 pages, 8 figure
Systems Biology Approach to Late-Onset Alzheimer\u27s Disease Genome-Wide Association Study Identifies Novel Candidate Genes Validated Using Brain Expression Data and \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e Experiments
Introduction—We sought to determine whether a systems biology approach may identify novel late-onset Alzheimer\u27s disease (LOAD) loci.
Methods—We performed gene-wide association analyses and integrated results with human protein-protein interaction data using network analyses. We performed functional validation on novel genes using a transgenic Caenorhabditis elegans Aβ proteotoxicity model and evaluated novel genes using brain expression data from people with LOAD and other neurodegenerative conditions.
Results—We identified 13 novel candidate LOAD genes outside chromosome 19. Of those, RNA interference knockdowns of the C. elegans orthologs of UBC, NDUFS3, EGR1, and ATP5H were associated with Aβ toxicity, and NDUFS3, SLC25A11, ATP5H, and APP were differentially expressed in the temporal cortex.
Discussion—Network analyses identified novel LOAD candidate genes. We demonstrated a functional role for four of these in a C. elegans model and found enrichment of differentially expressed genes in the temporal cortex
HECTD2, a candidate susceptibility gene for Alzheimer's disease on 10q
Background: Late onset Alzheimer's disease (LOAD) is a neurodegenerative disorder characterised by the deposition of amyloid plaques and neurofibrillary tangles in the brain and is the major cause of dementia. Multiple genetic loci, including 10q, have been implicated in LOAD but to date, with the exception of APOE, the underlying genes have not been identified. HECTD2 maps to 10q and has been implicated in susceptibility to human prion diseases which are also neurodegenerative conditions associated with accumulation of misfolded host proteins. In this study we test whether the HECTD2 susceptibility allele seen in prion disease is also implicated in LOAD.Methods: DNA from 320 individuals with Alzheimer's disease and 601 controls were genotyped for a HECTD2 intronic tagging SNP, rs12249854 (A/T). Groups were further analysed following stratification by APOE genotype.Results: The rs12249854 minor allele (A) frequency was higher (5.8%) in the Alzheimer's disease group as compared to the controls (3.9%), however, this was not statistically significant (P = 0.0668). No significant difference was seen in minor allele frequency in the presence or absence of the APOE epsilon 4 allele.Conclusion: The common haplotypes of HECTD2, tagged by rs12249854, are not associated with susceptibility to LOAD
Position statement for the diagnosis and management of anogenital warts
Background: Anogenital warts (AGW) can cause economic burden on healthcare systems and are associated with emotional, psychological and physical issues.
----- Objective: To provide guidance to physicians on the diagnosis and management of AGW.
----- Methods: Fourteen global experts on AGW developed guidance on the diagnosis and management of AGW in an effort to unify international recommendations. Guidance was developed based on published international and national AGW guidelines and an evaluation of relevant literature published up to August 2016. Authors provided expert opinion based on their clinical experiences.
----- Results: A checklist for a patient's initial consultation is provided to help physicians when diagnosing AGW to get the relevant information from the patient in order to manage and treat the AGW effectively. A number of frequently asked questions are also provided to aid physicians when communicating with patients about AGW. Treatment of AGW should be individualized and selected based on the number, size, morphology, location, and keratinization of warts, and whether they are new or recurrent. Different techniques can be used to treat AGW including ablation, immunotherapy and other topical therapies. Combinations of these techniques are thought to be more effective at reducing AGW recurrence than monotherapy. A simplified algorithm was created suggesting patients with 1-5 warts should be treated with ablation followed by immunotherapy. Patients with >5 warts should use immunotherapy for 2 months followed by ablation and a second 2-month course of immunotherapy. Guidance for daily practice situations and the subsequent action that can be taken, as well as an algorithm for treatment of large warts, were also created.
----- Conclusion: The guidance provided will help physicians with the diagnosis and management of AGW in order to improve the health and quality of life of patients with AGW
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