Scheduling problems with the effects of deterioration and learning

Author name used in this publication: T. C. E. Cheng2006-2007 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Haar expectations of ratios of random characteristic polynomials

We compute Haar ensemble averages of ratios of random characteristic polynomials for the classical Lie groups K = O(N), SO(N), and USp(N). To that end, we start from the Clifford-Weyl algebera in its canonical realization on the complex of holomorphic differential forms for a C-vector space V. From it we construct the Fock representation of an orthosymplectic Lie superalgebra osp associated to V. Particular attention is paid to defining Howe's oscillator semigroup and the representation that partially exponentiates the Lie algebra representation of sp in osp. In the process, by pushing the semigroup representation to its boundary and arguing by continuity, we provide a construction of the Shale-Weil-Segal representation of the metaplectic group. To deal with a product of n ratios of characteristic polynomials, we let V = C^n \otimes C^N where C^N is equipped with its standard K-representation, and focus on the subspace of K-equivariant forms. By Howe duality, this is a highest-weight irreducible representation of the centralizer g of Lie(K) in osp. We identify the K-Haar expectation of n ratios with the character of this g-representation, which we show to be uniquely determined by analyticity, Weyl group invariance, certain weight constraints and a system of differential equations coming from the Laplace-Casimir invariants of g. We find an explicit solution to the problem posed by all these conditions. In this way we prove that the said Haar expectations are expressed by a Weyl-type character formula for all integers N \ge 1. This completes earlier work by Conrey, Farmer, and Zirnbauer for the case of U(N).Comment: LaTeX, 70 pages, Complex Analysis and its Synergies (2016) 2:

Single-machine scheduling with deteriorating jobs under a series-parallel graph constraint

Author name used in this publication: C. T. NgAuthor name used in this publication: T. C. E. Cheng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Single-machine scheduling with a time-dependent learning effect

Author name used in this publication: J.-B. WangAuthor name used in this publication: C. T. NgAuthor name used in this publication: T. C. E. Cheng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

First-principles study of alkali-metal intercalation in disordered carbon anode materials

The intercalation of alkali metals in disordered carbon anode materials is studied by a combination of first-principles and machine-learning methods.</p

An economical fabrication technique for SIMOX using plasma immersion ion implantation

Buried oxide layers in Si were fabricated using non-mass analyzed plasma immersion ion implantation (PIII). The implantation was carried out by applying a large negative bias to a Si wafer immersed in an oxygen plasma and a dose of 3×1017 cm-2 of oxygen was implanted in about three minutes. Cross section transmission electron microscopy (XTEM) and Rutherford backscattering spectrometry (RES) were used to characterize the wafers. Our results indicate that a continuous buried oxide layer with a single crystal silicon overlayer was synthesizedpublished_or_final_versio

The Primary Enveloped Virion of Herpes Simplex Virus 1: Its Role in Nuclear Egress

Many viruses migrate between different cellular compartments for successive stages of assembly. The HSV-1 capsid assembles in the nucleus and then transfers into the cytoplasm. First, the capsid buds through the inner nuclear membrane, becoming coated with nuclear egress complex (NEC) protein. This yields a primary enveloped virion (PEV) whose envelope fuses with the outer nuclear membrane, releasing the capsid into the cytoplasm. We investigated the associated molecular mechanisms by isolating PEVs from US3-null-infected cells and imaging them by cryo-electron microscopy and tomography. (pUS3 is a viral protein kinase in whose absence PEVs accumulate in the perinuclear space.) Unlike mature extracellular virions, PEVs have very few lycoprotein spikes. PEVs are ~20% smaller than mature virions, and the little space available between the capsid and the NEC layer suggests that most tegument proteins are acquired later in the egress pathway. Previous studies have proposed that NEC is organized as hexamers in honeycomb arrays in PEVs, but we find arrays of heptameric rings in extracts from US3-nullinfected cells. In a PEV, NEC contacts the capsid predominantly via the pUL17/pUL25 complexes which are located close to the capsid vertices. Finally, the NEC layer dissociates from the capsid as it leaves the nucleus, possibly in response to pUS3- mediated phosphorylation. Overall, nuclear egress emerges as a process driven by a program of multiple weak interactions

Intraâ abdominal chylovenous bypass treats retroperitoneal lymphangiomatosis

BackgroundRetroperitoneal lymphangiomatosis (RL) is a rare form of primary lymphedema featuring aberrant retroperitoneal lymphatic proliferation. It causes recurrent cellulitis, repeated interventions, and poor life quality. This study aimed to investigate proper diagnositc criteria and surgical outcomes for RL with extremity lymphedema.MethodsBetween 2012 and 2018, 44 primary lowerâ extremity lymphedema cases received lymphoscintigraphy, magnetic resonance imaging, and singleâ photon electron computed tomography to detect RL. RL patients underwent vascularized lymph node transfers (VLNT) for extremity lymphedema and intraâ abdominal sideâ toâ end chylovenous bypasses (CVB) for chylous ascites. Complications, CVB patency, and quality of life were evaluated postoperatively.ResultsSix RL patients (mean age of 30.3 years) had chylous ascites with five had lowerâ extremity lymphedema. All CVBs remained patent, though one required reâ anastomosis, giving a 100% patency rate. Four unilateral and one bilateral extremity lymphedema underwent six VLNTs with 100% flap survival. Patients reported improved quality of life (Pâ =â 0.023), decreased cellulitis incidence (Pâ =â 0.041), and improved mean lymphedema circumference (Pâ =â 0.043). All patients resumed a normal diet and activity.ConclusionsEvaluating primary lowerâ extremity lymphedema patients with MRI and SPECT could reveal a 13.6% prevalence of RL and guide treatment of refractory extremity lymphedema. Intraâ abdominal CVB with VLNT effectively treated RL with chylous ascites and extremity lymphedema.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152842/1/jso25514.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152842/2/jso25514_am.pd

Fundamental studies of copper anode passivation during electrorefining: Part III The effect of thiourea

Thiourea has been extensively used as a grain refiner in industrial copper electrorefining processes. The influence of thiourea on deposit structure and morphology has received considerable study; however, the effect of thiourea and its degradation chemistry on the passivation behavior of commercial copper anodes is still not fully understood. This study was conducted to provide useful information regarding the electrochemical response of a commercial copper anode in the absence and presence of thiourea. Chronopotentiometry measurements were performed in synthetic electrolytes containing different thiourea concentrations and in industrial electrolytes obtained directly from a commercial tank house. Passivation time (t(p)) and periodic passivation phenomena were found to be closely associated with thiourea concentration and degradation

Cefotaxime/sulbactam plus gentamicin as a potential carbapenem- and amikacin-sparing first-line combination for neonatal sepsis in high ESBL prevalence settings

BACKGROUND: Infection with ESBL-producing Enterobacteriaceae infection is ubiquitous in some neonatal ICUs and increasing levels of antibiotic resistance are a cause for urgent concern. Delineation of bacterial and viral sepsis can be challenging, often leading to patients receiving empirical antibiotics without or whilst waiting for a definitive causal diagnosis. Empirical therapy is often dependent on broad-spectrum ‘Watch’ antibiotics, contributing to further resistance. METHODS: ESBL-producing Enterobacteriaceae clinical isolates found to have caused neonatal sepsis and meningitis underwent a detailed in vitro screening including susceptibility testing, chequerboard combination analysis and hollow-fibre infection model dynamic analyses using combinations of cefotaxime, ampicillin and gentamicin in combination with β-lactamase inhibitors. RESULTS: Additivity or synergy was found for all antibiotic combinations against seven Escherichia coli and three Klebsiella pneumoniae clinical isolates. Cefotaxime or ampicillin plus sulbactam combined with gentamicin was able to consistently inhibit the growth of ESBL-producing isolates at typical neonatal doses, and the combination cleared the hollow-fibre infection model system of organisms resistant to each agent alone. The combination of cefotaxime/sulbactam and gentamicin was consistently bactericidal at clinically achievable concentrations (Cmax of 180, 60 and 20 mg/L for cefotaxime, sulbactam and gentamicin, respectively). CONCLUSIONS: The addition of sulbactam to cefotaxime or ampicillin to the typical first-line empirical therapy could obviate the need for carbapenems and amikacin in settings with high ESBL-infection prevalence