320 research outputs found
The subpower membership problem for semigroups
Fix a finite semigroup and let be tuples in a direct
power . The subpower membership problem (SMP) asks whether can be
generated by . If is a finite group, then there is a
folklore algorithm that decides this problem in time polynomial in . For
semigroups this problem always lies in PSPACE. We show that the SMP for a full
transformation semigroup on 3 letters or more is actually PSPACE-complete,
while on 2 letters it is in P. For commutative semigroups, we provide a
dichotomy result: if a commutative semigroup embeds into a direct product
of a Clifford semigroup and a nilpotent semigroup, then SMP(S) is in P;
otherwise it is NP-complete
Data-based Collaboration on a Grand Scale
Modern spatial planning strongly relies on computer systems such as Computer-Aided Design tools (CAD) and Geographic Information Systems (GIS). These, in turn, depend upon Database Management Systems: complex computer systems designed to optimize data storage and retrieval. In this paper we try to sketch a short survey of current DBMS technologies for the non-expert by overviewing their history, targets, strengths, and weaknesses. The goal is to make the spatial planning community more aware of the present and developing technologies such that future projects started can take advantage of the most suitable technology
Open Street Map for Multi-Modal Freight Transport Planning
Route planning for transportation of goods is an essential task. Determining a route for e.g. a truck is simple if the road network including the legal and technical limitations like truck ban or weight restriction are known. Planning of multi-modal routes is a bit more complex. The change of mode of transportation is only possible at specific locations. This change takes time and is often subjet to additional technical or legal restrictions. Thus the different networks, e.g., road and rail, need to be connected.
An obvious approach for multi-modal transport planning would be the use of Open Street Map (OSM) data since it does not only contain information about roads but also about trains and rivers. In this paper we first present some existing solutions for multi-modal transport planning and then discuss the use of OSM data in such a process. We identify missing elements in OSM and show opportunities for further development and interventions
Effect of corticosteroids during ongoing drug exposure in pantoprazole-induced interstitial nephritis
Acute interstitial nephritis (AIN) represents a significant cause of acute renal failure in hospital practice. An increasing number of drugs are known to cause AIN. Due to the lack of prospective, randomized clinical trials, the most effective management is still uncertain, especially the role of steroids in the resolution of interstitial nephritis remains to be further defined. We report on a case with pantoprazole-induced interstitial nephritis and on the effect of steroids during ongoing drug exposure. In spite of ongoing drug exposure, steroids led to almost complete resolution of the inflammatory infiltrates. Early diagnosis of interstitial nephritis by renal biopsy and identification of the causative drug and its withdrawal remains the mainstay of treatment. However, the additional use of steroids has the potential to eradicate inflammatory infiltrates more rapidly and completely and may thus be important to minimize subsequent chronic damag
Settling the Syrian Conflict: Legal Pitfalls in a Political Agreement
Markus MayrThe planned Geneva conference will attempt to end the Syrian conflict with a political agreement. Such an agreement has to define a transitional order that accommodates the different groups’ interests. Meanwhile, serious violations of international humanitarian and human rights law by government forces and the armed opposition continue to be documented and pose familiar questions regarding accountability and reparation. The result is well-known: actors that are essential to end the conflict are the ones that have been involved in abuses and are to be held accountable. Therefore, calls for justice, accountability and truth create incentives to resist the conclusion of and adherence to an agreement
Heat diffusion blurs photothermal images with increasing depth
In this tutorial, we aim to directly recreate some of our "aha" moments when
exploring the impact of heat diffusion on the spatial resolution limit of
photothermal imaging. Our objective is also to communicate how this physical
limit can nevertheless be overcome and include some concrete technological
applications. Describing diffusion as a random walk, one insight is that such a
stochastic process involves not only a Gaussian spread of the mean values in
space, with the variance proportional to the diffusion time, but also temporal
and spatial fluctuations around these mean values. All these fluctuations
strongly influence the image reconstruction immediately after the short heating
pulse. The Gaussian spread of the mean values in space increases the entropy,
while the fluctuations lead to a loss of information that blurs the
reconstruction of the initial temperature distribution and can be described
mathematically by a spatial convolution with a Gaussian thermal
point-spread-function (PSF). The information loss turns out to be equal to the
mean entropy increase and limits the spatial resolution proportional to the
depth of the imaged subsurface structures. This principal resolution limit can
only be overcome by including additional information such as sparsity or
positivity. Prior information can be also included by using a deep neural
network with a finite degrees of freedom and trained on a specific class of
image examples for image reconstruction
Rapid adaptation of the intrarenal resistance index after living donor kidney transplantation
Background. Limited data exist concerning changes of renal perfusion directly after kidney transplantation. Colour-coded duplex sonography is the accepted method to assess kidney perfusion after transplantation. A widely used, although unspecific, Doppler parameter is the intrarenal resistance index (RI). The aim of this study was to clarify the influence of different patient- and procedure-related factors on RI before and immediately after living kidney transplantation. Methods. In a prospective study, 80 living kidney transplantation donor-recipient pairs were included. RI was measured in the donor 1 to 3 days before nephrectomy and in the recipient during the first hour after transplantation to examine the influence of age, heart rate, duration of cold and warm ischaemia time and immunosuppressive medications. Results. Mean RI did not differ between donors and recipients. RI correlated with age, both in donors (r = 0.58, P < 0.001) and recipients (r = 0.39, P < 0.001). In recipients, 10 or more years younger than their donors (n = 24), an average decrease of 0.05 in RI compared to the donors' value was observed (P = 0.01). Heart rate, cold and warm ischaemia time and immunosuppressive medications had no influence on the recipient RI. In patients with delayed graft function, a significant increase in RI within 14 days was observed. However, the initial RI was not predictive of graft function. Conclusions. The transplanted kidney seems to be able to adjust its RI within a short time despite several potential harmful factors that can occur during the transplantatio
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