519 research outputs found
Cost Accounting and Pricing Improvement at Helmond Print: Using Xeikon Digital Colour Printing Equipment: A Case study
Helmond Print B.V., a (fictional) Dutch print provider, is facing competitive problems. The student is expected to step into the role of an independent expert advising Helmond Print''s owner and manager. The first objective is to let the student find out, from a piece of qualitative and quantitative information about Xeikon N.V. machines, that the cost structure is much different than currently assumed. The student should try to improve the cost calculations, which will require linear and both non-linear regression analysis. A second objective is to make the student realize that the incorrect cost calculations affected Helmond Print''s pricing policy and may have lead to the competitive problems faced now. The student should therefore link their investigations to pricing, search for the weak spots in the current pricing policy and make suggestions for improvement. (Note: a solution to the case can be obtained by simple request)management and organization theory ;
Transport properties of strongly correlated electrons in quantum dots using a simple circuit model
Numerical calculations are shown to reproduce the main results of recent
experiments involving nonlocal spin control in nanostructures (N. J. Craig et
al., Science 304, 565 (2004)). In particular, the splitting of the
zero-bias-peak discovered experimentally is clearly observed in our studies. To
understand these results, a simple "circuit model" is introduced and shown to
provide a good qualitative description of the experiments. The main idea is
that the splitting originates in a Fano anti-resonance, which is caused by
having one quantum dot side-connected in relation to the current's path. This
scenario provides an explanation of Craig et al.'s results that is alternative
to the RKKY proposal, which is here also addressed.Comment: 5 pages, 5 figure
Transport through quantum dots: A combined DMRG and cluster-embedding study
The numerical analysis of strongly interacting nanostructures requires
powerful techniques. Recently developed methods, such as the time-dependent
density matrix renormalization group (tDMRG) approach or the embedded-cluster
approximation (ECA), rely on the numerical solution of clusters of finite size.
For the interpretation of numerical results, it is therefore crucial to
understand finite-size effects in detail. In this work, we present a careful
finite-size analysis for the examples of one quantum dot, as well as three
serially connected quantum dots. Depending on odd-even effects, physically
quite different results may emerge from clusters that do not differ much in
their size. We provide a solution to a recent controversy over results obtained
with ECA for three quantum dots. In particular, using the optimum clusters
discussed in this paper, the parameter range in which ECA can reliably be
applied is increased, as we show for the case of three quantum dots. As a
practical procedure, we propose that a comparison of results for static
quantities against those of quasi-exact methods, such as the ground-state
density matrix renormalization group (DMRG) method or exact diagonalization,
serves to identify the optimum cluster type. In the examples studied here, we
find that to observe signatures of the Kondo effect in finite systems, the best
clusters involving dots and leads must have a total z-component of the spin
equal to zero.Comment: 16 pages, 14 figures, revised version to appear in Eur. Phys. J. B,
additional reference
Calculations and Competitive Benchmarking: A Case study: Xeikon N.V.
Xeikon N.V. is a young NASDAQ-listed company in the digital colour printing market. First of all, the student is expected to step into the role of an independent expert advising Xeikon''s CEO. Although it is already clear that digital colour printing is competitive mainly at relatively small order quantities, the student is expected to give more specific information about the quantities for which Xeikon equipment is competitive. This will require different kinds of break-even analysis. Furthermore, students should analyse cost data using a learning curve model. In doing so, they should address the limitations of the model, test the usefulness in this situation and recognize that learning is not the right term in this context. The investigations require the use of regression analysis. (Note: a case solution can be obtained by simple request)management and organization theory ;
Comparison of different enrichment media for the isolation of Salmonella from naturally infected slaughter pigs
The present study aimed to assess the impact of different enrichment media, Reppaport-vassiliadis (RV) broth, Rappaport-Vassiliadis Soya (RVS) broth, Diagnostic semi-solid Salmonella (DIA) agar, Simple Method Salmonella (SMS) agar, Modified Semisolid Rappaport Vassiliadis (MSRV) agar and Mueller Kauffmann Tetrathionate novobiocin (MKTTn) broth, on the detection of Salmonella as well as on the isolated serotype and genotype
Identification campaign of supernova remnant candidates in the Milky Way - I: Chandra observation of G308.3-1.4
ROSAT all-sky survey (RASS) data have provided another window to search for
supernova remnants (SNRs). In reexamining this data archive, a list of
unidentified extended X-ray objects have been suggested as promising SNR
candidate. However, most of these targets have not yet been fully explored by
the state-of-art X-ray observatories. For selecting a pilot target for a
long-term identification campaign, we have observed the brightest candidate,
G308.3-1.4, with Chandra X-ray observatory. An incomplete shell-like X-ray
structure which well-correlated with the radio shell emission at 843 MHz has
been revealed. The X-ray spectrum suggests the presence of a shock-heated
plasma. All these evidences confirm G308.3-1.4 as a SNR. The brightest X-ray
point source detected in this field-of-view is also the one locates closest to
the geometrical center of G308.3-1.4, which has a soft spectrum. The intriguing
temporal variability and the identification of optical/infrared counterpart
rule out the possibility of an isolated neutron star. On the other hand, the
spectral energy distribution from Ks band to R band suggests a late-type star.
Together with a putative periodicity of \sim1.4 hrs, the interesting excesses
in V, B bands and H-alpha suggest this source as a promising candidate of a
compact binary survived in a supernova explosion (SN).Comment: 19 pages, 10 figures, 2 tables, accepted for publication in Ap
Effect of the use of organic acids in drinking water during the last two weeks prior to slaughter on salmonella shedding
In this study we investigated the effect of adding organic acids to the drinking water of finishing pigs two weeks prior to slaughter on the shedding and prevalence rate of Salmonella at slaughter. One hundred animals from 4 Belgian pig herds infected with Salmonella were included. Fifty of these ammals received drinking water supplemented with a mixture of different organic acids during 14 days prior to slaughter. Non-treated animals served as controls. Different samples were taken: contents of ileum and rectum, mesenteric lymph nodes and carcass swabs. All samples were submitted to Salmonella isolation using standard procedures. The results could not reveal a significant difference between both groups. This may be due to the limited power of the study (only 50 animals sampled in each group) or due to the fact that the treatment duration was insufficient to prove the benefit of the used organic acids
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