301 research outputs found
Inventory management with advance capacity information
One of the important aspects of supply chain management is dealing with demand and supply uncertainty. The uncertainty of future supply can be reduced, if a company is able to obtain advance capacity information (ACI) on future supply/production capacity availability from its supplier. We address a periodic-review inventory system under stochastic demand and stochastic limited supply, for which ACI is available. We show that the optimal ordering policy is a state-dependent base stock policy characterized by a base stock level that is a function of ACI. We establish a link to inventory models using advance demand information (ADI) by developing a capacitated inventory system with ADI, and showing that the model is closely related to the proposed ACI model. Our numerical results reveal several managerial insights. In particular, we show that ACI is most beneficial when there exists sufficient flexibility to react to anticipated demand and supply capacity mismatches. Further, most of the benefits can be reached with only limited future visibility. We also show that the system parameters affecting the value of ACI interact in a complex way, and therefore need to be considered in an integrated manner
Review of Antlions (Insecta: Neuroptera: Myrmeleontidae) in North Macedonia
We present the state of knowledge on the family Myrmeleontidae occurring in North Macedonia based on published records, museum specimens and new samples, and provide a comprehensive species list. North Macedonia represents only 3.9% of the area of the Balkan Peninsula but harbours 19 species belonging to 14 antlion genera, i.e., 61% of the peninsular fauna. We report collection localities, literature records and biological data for each species. Three species, Nemoleon poecilopterus, Neuroleon assimilis and Myrmeleon inconspicuus, are reported for the first time in North Macedonia. The genus Nemoleon Navás is also reported for the first time in the country
An Adiabatic Theorem without a Gap Condition
The basic adiabatic theorems of classical and quantum mechanics are
over-viewed and an adiabatic theorem in quantum mechanics without a gap
condition is described.Comment: Talk at QMath 7, Prague, 1998. 10 pages, 7 figure
Intermixture of extended edge and localized bulk energy levels in macroscopic Hall systems
We study the spectrum of a random Schroedinger operator for an electron
submitted to a magnetic field in a finite but macroscopic two dimensional
system of linear dimensions equal to L. The y direction is periodic and in the
x direction the electron is confined by two smooth increasing boundary
potentials. The eigenvalues of the Hamiltonian are classified according to
their associated quantum mechanical current in the y direction. Here we look at
an interval of energies inside the first Landau band of the random operator for
the infinite plane. In this energy interval, with large probability, there
exist O(L) eigenvalues with positive or negative currents of O(1). Between each
of these there exist O(L^2) eigenvalues with infinitesimal current
O(exp(-cB(log L)^2)). We explain what is the relevance of this analysis to the
integer quantum Hall effect.Comment: 29 pages, no figure
AN INVENTORY OF PHOTOGRAPHS OF ZINC ELECTRODEPOSITED FROM ACID ELECTROLYTES
Electrodeposition of zinc from acid electrolytes has been studied by several investigators in this laboratory. A large number of zinc deposits have been observed and photographs (SEM, micrographs, experimental equipment, and line drawings) have been prepared over the years 1976-1983. These photos are compiled in this LBL report to facilitate their future use by others. The tables in this report list the experimental conditions and corresponding identification numbers of photographs that are on file in the Photography Services Laboratory at the Lawrence Berkeley Laboratory. Several samples of these zinc deposits are shown
Obstructive jaundice secondary to pancreatic head adenocarcinoma in a young teenage boy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Pancreatic adenocarcinoma is extremely rare in childhood. We report a case of metastatic pancreatic adenocarcinoma in a 13-year-old boy, revealed by jaundice.</p> <p>Case presentation</p> <p>A 13-year-old Moroccan boy was admitted with obstructive jaundice to the children's Hospital of Rabat, Department of Pediatric Oncology. Laboratory study results showed a high level of total and conjugated bilirubin. Computerized tomography of the abdomen showed a dilatation of the intra-hepatic and extra-hepatic bile ducts with a tissular heterogeneous tumor of the head of the pancreas and five hepatic lesions. Biopsy of a liver lesion was performed, and a histopathological examination of the sample confirmed the diagnosis of metastatic ductal adenocarcinoma of the pancreas. Our patient underwent a palliative biliary derivation. After that, chemotherapy was administered (5-fluorouracil and epirubicin), however no significant response to treatment was noted and our patient died six months after diagnosis.</p> <p>Conclusion</p> <p>Malignant pancreatic tumors, especially ductal carcinomas, are exceedingly rare in the pediatric age group and their clinical features and treatment usually go unappreciated by most pediatric oncologists and surgeons.</p
Genotyping of invasive Ponto-Caspian gobies in Croatia
The biology and ecology of non-native freshwater Ponto-Caspian (P-C) gobies: monkey goby, Neogobius fluviatilis
(Pallas, 1814), round goby, Neogobius melanostomus (Pallas, 1814) and bighead goby, Ponticola kessleri (Günther, 1861)
have been studied in Croatia, but the genetic structure of populations in the Sava River catchment remains unknown. Only
a single mitochondrial DNA cytochrome b haplotype, consistent with native Black Sea populations, has been detected
within Croatian populations. Based on emerging molecular evidence, the invasive potential (e.g. upstream migration and
environmental plasticity) of individual non-native gobies within the Sava River catchment, may be influenced by genetic
structuring
Normal transport properties for a classical particle coupled to a non-Ohmic bath
We study the Hamiltonian motion of an ensemble of unconfined classical
particles driven by an external field F through a translationally-invariant,
thermal array of monochromatic Einstein oscillators. The system does not
sustain a stationary state, because the oscillators cannot effectively absorb
the energy of high speed particles. We nonetheless show that the system has at
all positive temperatures a well-defined low-field mobility over macroscopic
time scales of order exp(-c/F). The mobility is independent of F at low fields,
and related to the zero-field diffusion constant D through the Einstein
relation. The system therefore exhibits normal transport even though the bath
obviously has a discrete frequency spectrum (it is simply monochromatic) and is
therefore highly non-Ohmic. Such features are usually associated with anomalous
transport properties
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