3,666 research outputs found
Self-dual solutions of Yang-Mills theory on Euclidean AdS space
We find non-trivial, time-dependent solutions of the (anti) self-dual
Yang-Mills equations in the four dimensional Euclidean Anti-de Sitter space. In
contrast to the Euclidean flat space, the action depends on the moduli
parameters and the charge can take any non-integer value.Comment: 11 pages, 2 figures; version 2: new references added, to appear in
PR
Comment on the new AdS universe
We show that Bonnor's new Anti-de Sitter (AdS) universe and its D-dimensional
generalization is the previously studied AdS soliton.Comment: 2 pages; version 2: major changes including the titl
Project Selection in Facility and Infrastructure Maintenance Organizations
The current Air Force Civil Engineer Center (AFCEC) built infrastructure Facility Sustainment Restoration and Modernization (FSRM) portfolio management methodology results in an unbalanced project portfolio. The consequence of this unbalance is that majority of the funding goes towards buildings on the flightline and Facility Support Services activities do not get adequate funding which leads to further deterioration of those facilities. This research investigates whether decision support framework based on Value-Focused Thinking (VFT) process yields better project selection outcomes for facility and infrastructure maintenance organizations. To accomplish that, the investigation focuses on understanding current AFCEC decision support methodology, building an alternative one based on VFT process, and then applying the result to a sampling of projects. Findings of the investigation prove that the VFT process yields a decision support framework that successfully balances FSRM project portfolio by ranking the projects based on their level of contribution to decision-maker’s values affecting facility and infrastructure maintenance organizations
Workload Balancing in Printed Circuit Board Assembly Shops
Son yıllarda baskı devre kartlarının (BDK) dizgisinde nümerik veya bilgisayar kontrollü elektronik dizgi makinalarının kullanımı yaygın hale gelmiştir. Ancak, bu beraberinde komponent tiplerinin makinalara atanması, kart üretim çizelgelemesi, besleyici düzeni ve dizgi sırası gibi karmaşık yöneylem araştırması problemlerini getirmiştir. Bu çalışmada, birbirinden farklı iki makinanın aynı hatta olması durumu için komponentlerin makinalara atanması problemi ele alınmıştır. Bu problemin çözümü için üç ayrı sezgisel algoritma geliştirilmiş ve performansları örnek veriler üzerinde incelenmiştir.In assembling printed circuit boards (PCB), the use of numerically or computer controlled electronic component placement machines has become quite popular in the last decades. However, serious operations research problems arise through their use such as, allocation of component types to machines, board production schedule, feeder configuration and placement sequencing. In this study, the problem of allocation of component types to machines is taken up where two non-identical machines are deployed serially on a line to complete the assembly process of PCBs. For the solution of this problem three heuristic algorithms are suggested and their performances are investigated on experimental data
Workload Balancing in Printed Circuit Board Assembly Shops
Son yıllarda baskı devre kartlarının (BDK) dizgisinde nümerik veya bilgisayar kontrollü elektronik dizgi makinalarının kullanımı yaygın hale gelmiştir. Ancak, bu beraberinde komponent tiplerinin makinalara atanması, kart üretim çizelgelemesi, besleyici düzeni ve dizgi sırası gibi karmaşık yöneylem araştırması problemlerini getirmiştir. Bu çalışmada, birbirinden farklı iki makinanın aynı hatta olması durumu için komponentlerin makinalara atanması problemi ele alınmıştır. Bu problemin çözümü için üç ayrı sezgisel algoritma geliştirilmiş ve performansları örnek veriler üzerinde incelenmiştir.In assembling printed circuit boards (PCB), the use of numerically or computer controlled electronic component placement machines has become quite popular in the last decades. However, serious operations research problems arise through their use such as, allocation of component types to machines, board production schedule, feeder configuration and placement sequencing. In this study, the problem of allocation of component types to machines is taken up where two non-identical machines are deployed serially on a line to complete the assembly process of PCBs. For the solution of this problem three heuristic algorithms are suggested and their performances are investigated on experimental data
One Juliet and four Romeos: VeA and its methyltransferases
Fungal secondary metabolism has become an important research topic with great
biomedical and biotechnological value. In the postgenomic era, understanding the diversity
and the molecular control of secondary metabolites (SMs) are two challenging tasks
addressed by the research community. Discovery of the LaeA methyltransferase 10 years
ago opened up a new horizon on the control of SM research when it was found
that expression of many SM gene clusters is controlled by LaeA. While the molecular
function of LaeA remains an enigma, discovery of the velvet family proteins as interaction
partners further extended the role of the LaeA beyond secondary metabolism. The
heterotrimeric VelB–VeA–LaeA complex plays important roles in development, sporulation,
secondary metabolism, and pathogenicity. Recently, three other methyltransferases have
been found to associate with the velvet complex, the LaeA-like methyltransferase F and
the methyltransferase heterodimers VipC–VapB. Interaction of VeA with at least four
methyltransferase proteins indicates a molecular hub function for VeA that questions: Is
there a VeA supercomplex or is VeA part of a highly dynamic cellular control network with
many different partners
Effect of the glutenin genes on quality parameters in common wheat
Association of glutenin alleles with bread quality has long been known and identification of glutenin alleles may be very informative for the quality of the breeder’s material. In this study, 64 wheat genotypes were evaluated for high and low molecular weight glutenin alleles (Glu-1 and Glu-3) and some quality parameters. Of the identified glutenin alleles, eleven were at the Glu-1 loci and 15 were at the Glu-3 loci. Highly significant (P<0.001) differences were found among the genotypes for all quality parameters. Associations of glutenin alleles with the quality parameters were also found significant. The positive effective glutenin alleles of Glu loci on quality traits were 1 at Glu-A1, 13+16, 17+18 and 7+8 at Glu-B1 and 5+10 at Glu-D1, and A3d, A3e, A3f and A3b at GluA3, B3a, B3b and B3g at Glu-B3 and D3a at Glu-D3. The negative effective glutenin alleles of Glu loci on quality traits were null allele at Glu-A1, 7, 7+9 and 14+15 at Glu-B1, 2+12 at Glu-D1 loci, and A3a, A3c at Glu-A3, B3f, B3c at Glu-B3 and D3c at Glu-D3
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