Associahedron, cyclohedron, and permutohedron as compactifications of configuration spaces

As in the case of the associahedron and cyclohedron, the permutohedron can also be defined as an appropriate compactification of a configuration space of points on an interval or on a circle. The construction of the compactification endows the permutohedron with a projection to the cyclohedron, and the cyclohedron with a projection to the associahedron. We show that the preimages of any point via these projections might not be homeomorphic to (a cell decomposition of) a disk, but are still contractible. We briefly explain an application of this result to the study of knot spaces from the point of view of the Goodwillie-Weiss manifold calculus.Comment: 27 pages The new version gives a more detailed exposition for the projection from the cyclohedron to the associahedron as maps of compactifications of configuration spaces. We also develop a similar picture for the projection from the permutohedron to the cyclohedron/associahedro

An analysis of inventory turnover in the Belgian manufacturing industry, wholesale and retail and the financial impact on inventory reduction.

Various inventory studies have been published in the last decades. Some studies emphasize the importance of low inventories, other examine the evolution of inventories over time and especially focus on the impact of the just-in-time (JIT) revolution. The aim of this paper is to investigate the level of inventories held by Belgian companies at one moment in time, namely May 2004. First we examine differences in inventory ratios between manufacturing industry sectors as well as between wholesale and retail. We find empirical evidence that the type of production process is the most important driver for work in process inventory. The finished goods inventory ratio also differs significantly among industry sectors, but here the reasons for the difference are harder to distinguish. Finally we find the inventory ratio to be significantly higher in retail than in wholesale. Furthermore, we examine the financial impact of inventories in the manufacturing industry. We find that companies with very high inventory ratios have more chance to be bad financial performers. Regression analyses partially support the hypothesis of a negative relationship between inventory ratio and financial performance but significant results could not be obtained for all sectors.Inventory; Manufacturing;

Données sur les transferts du 137Cs et du 60Co dans un écosystème fluvial : le Rhône

L'étude radioécologique du Rhône permet d'évaluer qualitativement et quantitativement les radionucléides présents dans le fleuve. Les études menées in situ posent des questions concernant les modalités de transfert des radionucléides. Dans ce travail des expériences sont mises au point, afin d'analyser les mécanismes de bioconcentration dans les écosystèmes aquatiques. Pour le césium-137 les échanges entre l'eau, le sédiment et divers organismes aquatiques ont permis d'élaborer un modèle mathématique que l'on peut confronter aux valeurs mesurées sur le terrain. En ce qui concerne le Cobalt-60 les auteurs décrivent des expériences permettant l'évaluation de la contribution relative de l'eau et de la nourriture dans l'accumulation du radionucléide par un poisson.The radioecology of the Rhone Basin has been studied for the last 15 years. This has been an opportunity to make a quantitative and qualitative evaluation of radionuclides as a function of their different sources. Special attention is given to 137Cs (present both in fallout and liquid wastes) and 60Co, which characterize the liquid wastes of pressurised water reactors. In order to assess the transfer and bioconcentration of these two radionuclides in freshwater ecosystems, several experimental studies were undertaken.The 137Cs transfer studies were carried out with a 5-component experimental ecosystem and the data were included in a mathematical model. For 60Co, the experimental study concerns the relative contribution of water and food in the accumulation of the radionuclide by Cyprinus carpio.Water, sediment, plants and fishes were taken from 60 sampling stations set up along the river (figure 1). Water was filtrated, then percolated on resin columns. Sediment, plants and fishes were dried and burnt to ashes in an oven at 500° C. Radioactivity was measured by gamma spectrometry and radiochemistry.137Cs experimental transfers were studied between water, sediment, midge larvae, daphnid and carp. These components were taken in pairs in order to estimate the radionuclide transfer from one to the other. Thus ten experiments were carried out (figure 2). In order to study the relative importance of food and water as 60Co sources for the carp, an experiment was carried out simultaneously on three homogeneous groups of ten juvenile fishes. The individuals of the first group were maintained in separate aquaria and offered 45 daily rations of labelled food over a 63-day period. Bach carp of the other two groups was placed in a compartment of a large tank with contaminated water. One group was fed with radioactive food, the other with non-radioactive food (table 1).Natural radioactivity remained steady all along the river. It ranged around 1 Bq.l-1 in water, 2250 Bq.kg-1 DW in sediment, 1700 Bq.kg-1 DW in aquatic plants, 110 Bq.kg-1 WW in fish. The fallout impact was characterized by 137Cs presence. PWR liquid wastes contained mainly, 58Co, 60Co, 134 Cs, 137Cs. The Chernobyl fallout gave an increase of Cs and the presence of 103Ru and 106RU+Rh specially during May and June 1986 which later decreased (tables 2, 3 and 4).137Cs transfer between water and sediment was very fast and important. Less than 2 % of the radionuclide was released from sediment into a non-radioactive water. During the transfer from water to chironomids the larvae radioactivity increased steadily (figure 3). Conversely, the transfer from the sediment to larvae did not seem to depend on the contact time. The transfer from water to carp was regular without any steady state during the 63 days of the experiment (figure 3). Then the fish concentration factor was less than 5. For 42 days, the transfer factor from sediment to carp was 3.6.10-3. The retention factor from food to carp was 0.03 when fishes were fed with daphnids and 0.13 with chironomids. An experiment showed that the various ways of 137Cs transfer could have an added impact. Thus the carp radioactivity was the sum of the separate transfers. Water was responsible for 4 % of the fish 137 Cs concentration, sediment for 45 % and chironomids for 51 %.It is possible to include the different kinetic equations in a mathematical model. If the radioactivity of one of the components is known, the nuclide concentration can be computed in others, as a relation of the contact time, the quantity and quality of ingested food, etc... This model gives a concentration factor for juvenile carp of 1000 in 180 days and 500 for 3-year old fish. Considering the field conditions (e.g. seasonal nutritive cycles) the computed concentration factor in fish was between 200 and 350. For a 1 mBq.l-1 137Cs concentration in water, the model gave a concentration of 0.2 to 0.35 Bq.kg-1 WW in carp, which was the 137Cs radioactivity level measured in the Rhone fish before the Chernobyl accident.During the 60Co accumulation phase, the mean weight of the fish in the three groups increased exponentially and the resultant relative weight gain was 52-59 % after 63 days (table 5).The 60Co accumulation kinetics showed that the steady state should be reached after 165 days for fish exposed to 60Co in food, 92 days for fish exposed to radiocobalt in water and 120 days for fish exposed to 60Co in both sources (figure 4). According to the 60Co concentration in the fish in the three treated groups, the accumulation from water accounted for 75 % of the total radioactivity and the accumulation of the radionuclide from both water and food was in addition.Depuration of 60Co from carp was a relatively intensive process reflecting a high Co turnover. Biological half-lives for loss from the long-lived compartment ranged from 35d in fish previously contaminated by food, to 87d in fish previously contaminated by food, to 87d in fish previously contaminated by water (figure 5).137Cs and 60Co are the most concentrated radionuclides in liquid wastes of the pressurised water reactors, and they are often measured in the aquatic ecosystem components. Though it accounts for the highest fraction of total radioactivity in the liquid wastes, 60Co cobalt is not the most concentrated radionuclide in fish. Experimental studies show that it is primarily transferred from the water so it is logical that its concentration in fish remains at a low level. Conversely the 137Cs has a low concentration in water but as it is transferred simultaneously from water, sediment and food, its concentration in fish is still important. Moreover its 30 years half-life means that the cesium contamination of fish is a long and important process, all the more so as the source terms can add their own effects during time and space

Downregulation of genes with a function in axon outgrowth and synapse formation in motor neurones of the VEGF(delta/delta) mouse model of amyotrophic lateral sclerosis

Background: Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that stimulates vasculogenesis. It has also been shown to act as a neurotrophic factor in vitro and in vivo. Deletion of the hypoxia response element of the promoter region of the gene encoding VEGF in mice causes a reduction in neural VEGF expression, and results in adult-onset motor neurone degeneration that resembles amyotrophic lateral sclerosis (ALS). Investigating the molecular pathways to neurodegeneration in the VEGF(delta/delta) mouse model of ALS may improve understanding of the mechanisms of motor neurone death in the human disease. Results: Microarray analysis was used to determine the transcriptional profile of laser captured spinal motor neurones of transgenic and wild-type littermates at 3 time points of disease. 324 genes were significantly differentially expressed in motor neurones of presymptomatic VEGF(delta/delta) mice, 382 at disease onset, and 689 at late stage disease. Massive transcriptional downregulation occurred with disease progression, associated with downregulation of genes involved in RNA processing at late stage disease. VEGF(delta/delta) mice showed reduction in expression, from symptom onset, of the cholesterol synthesis pathway, and genes involved in nervous system development, including axonogenesis, synapse formation, growth factor signalling pathways, cell adhesion and microtubule-based processes. These changes may reflect a reduced capacity of VEGF(delta/delta) mice for maintenance and remodelling of neuronal processes in the face of demands of neural plasticity. The findings are supported by the demonstration that in primary motor neurone cultures from VEGF(delta/delta) mice, axon outgrowth is significantly reduced compared to wild-type littermates. Conclusions: Downregulation of these genes involved in axon outgrowth and synapse formation in adult mice suggests a hitherto unrecognized role of VEGF in the maintenance of neuronal circuitry. Dysregulation of VEGF may lead to neurodegeneration through synaptic regression and dying-back axonopathy

The Influence of Different Winemaking Techniques on the Extraction of Grape Tannins and Anthocyanins

The aim of this study was to determine the effect of different maceration techniques on the extractionof grape tannins and anthocyanins. Two cultivars (Cabernet Sauvignon and Shiraz) were harvested intwo different climatic regions (Durbanville and Simondium) at two different ripeness levels for the 2008and 2009 harvest seasons. Five basic winemaking processes were applied, namely a normal alcoholicfermentation (C), enzyme treatment (E), cold soaking (CM), post-maceration (PM), and a combinationof cold and post-maceration (CM+PM). At harvest the phenolic ripeness was determined with the Gloriesmethod, while the tannin concentration was determined with the methyl cellulose (MCP) method. Thegrapes in the warmer area had higher tannin levels than grapes harvested in the cooler area in both years.In the 2009 harvest season, the enzyme treatment extracted the highest levels of tannin. CM+PM showedthe best results of tannin extraction with early ripeness (Cabernet Sauvignon), and CM with fuller ripenessin the warm area. CM showed the best results with both early and fuller ripeness levels in the cooler area.PM showed the best results with the early ripeness levels, and the E treatment with the fuller ripenesslevels, in the warm area. CM+PM showed the best results with the early ripeness level in the cooler area,and varied results with the fuller ripeness levels. In both years, grapes from the cooler area containedmore anthocyanin than those from the warmer area. At a fuller ripeness level (2009) the treatments hadno effect

Endovascular Treatment of the Descending Thoracic Aorta

AbstractObjectives: to report our initial experience with endovascular stent graft repair of a variety of thoracic aortic pathology.Design: retrospective single center study.Material and methods: between February 2000 and January 2002, endovascular stent graft repair was performed in 26 patients: traumatic aortic isthmus rupture (n=3), Type B dissection (n=11) and descending thoracic aortic aneurysm (n=12). The deployed stent graft systems were AneuRx-Medtronic (n=1), Talent-Medtronic (n=13) and Excluder-Gore (n=12).Results: successful deployment of the stent grafts in the intended position was achieved in all patients. No hospital mortality neither paraplegia were observed. Late, non procedure related, death occurred in four patients (15%). Access artery complications with rupture of the iliac artery occurred in two patients and were managed by iliac-femoral bypass. The left subclavian artery was overstented in seven patients (27%). Only the first patient received a carotido-subclavian bypass. The mean maximal aortic diameter decreased significantly in patients treated for descending thoracic aneurysm. Only one patient had an endoleak type II after 6 months without enlargement of the aneurysm. Complete thrombosis of the thoracic false lumen occurred in all but one patient treated for Type B dissection 6 months postoperatively. Two patients underwent a consecutive stent graft placement, due to a large re-entry tear distal to the first stent graft.Conclusions: endovascular stent graft repair for Type B dissection, descending thoracic aneurysm and aortic isthmus rupture is a promising less-invasive alternative to surgical repair. Further studies are mandatory to determine its long-term efficacy

Fingermark age determinations: Legal considerations, review of the literature and practical propositions.

The question of the age of fingermarks is often raised in investigations and trials when suspects admit that they have left their fingermarks at a crime scene but allege that the contact occurred at a different time than the crime and for legal reasons. In the first part of this review article, examples from American appellate court cases will be used to demonstrate that there is a lack of consensus among American courts regarding the admissibility and weight of testimony from expert witnesses who provide opinions about the age of fingermarks. Of course, these issues are not only encountered in America but have also been reported elsewhere, for example in Europe. The disparity in the way fingermark dating cases were managed in these examples is probably due to the fact that no methodology has been validated and accepted by the forensic science community so far. The second part of this review article summarizes the studies reported on fingermark dating in the literature and highlights the fact that most proposed methodologies still suffer from limitations preventing their use in practice. Nevertheless, several approaches based on the evolution of aging parameters detected in fingermark residue over time appear to show promise for the fingermark dating field. Based on these approaches, the definition of a formal methodological framework for fingermark dating cases is proposed in order to produce relevant temporal information. This framework identifies which type of information could and should be obtained about fingermark aging and what developments are still required to scientifically address dating issues

Three-year randomised clinical trial to evaluate the clinical performance, quantitative and qualitative wear patterns of hybrid composite restorations

The aim of the study was to compare the clinical performance, quantitative and qualitative wear patterns of conventional hybrid (Tetric Ceram), micro-filled hybrid (Gradia Direct Posterior) and nano-hybrid (Tetric EvoCeram, TEC) posterior composite restorations in a 3-year randomised clinical trial. Sixteen Tetric Ceram, 17 TEC and 16 Gradia Direct Posterior restorations were placed in human molars and evaluated at baseline, 6, 12, 24 and 36 months of clinical service according to US Public Health Service criteria. The gypsum replicas at each recall were used for 3D laser scanning to quantify wear, and the epoxy resin replicas were observed under scanning electron microscope to study the qualitative wear patterns. After 3 years of clinical service, the three hybrid restorative materials performed clinically well in posterior cavities. Within the observation period, the nano-hybrid and micro-hybrid restorations evolved better in polishability with improved surface gloss retention than the conventional hybrid counterpart. The three hybrid composites showed enamel-like vertical wear and cavity-size dependant volume loss magnitude. Qualitatively, while the micro-filled and nano-hybrid composite restorations exhibited signs of fatigue similar to the conventional hybrid composite restorations at heavy occlusal contact area, their light occlusal contact areas showed less surface pitting after 3 years of clinical service

Interactive visualization of cell expansion process performance

As cell-based technologies are rapidly evolving beyond the laboratory scale, the demand for mass production of high quality cells is increasing. Unfortunately, only limited amounts of cells can be sourced from (human) donors. Therefore sequences of cell expansion steps are required to multiply the original number of cells taken from the donor biopsy to the amounts required for clinical application. Currently a large variety of expansion processes are used and described in literature. However, it is extremely difficult to compare them as many mesenchymal stem cell (MSC) subtypes are used in different culture vessels, with different medium compositions, etc. Moreover, adding to this variation in expansion strategies, within one process there can be significant fluctuations in outcome due to process variability and inherent donor-to-donor related variability. The aim of this work was to analyze the performance of a range of expansion processes for large-scale MSC expansion. Therefore a literature-based study was performed, currently resulting in a database of 73 individual cell expansion processes in 5 different types of culture vessels (microcarrier, (layered) flasks, hollow fiber-, multiplate-, and packed bed-bioreactor), 6 different types of MSCs and many different media compositions. The scale of the processes in terms of final cell numbers ranged between 7.5x106 and 1.1x1010 cells. An interactive process map was created where the scale, efficiency, cell type, culture method and load on downstream processing can be explored (see figure below). This interactive visualization tool provides an integrated perspective on the different culture processes and is able to increase the understanding on process comparability, attainable cell yield, scale-up strategies and the effect of certain critical process parameters on the expansion result. Please click Additional Files below to see the full abstract

M. Kontsevich's graph complex and the Grothendieck-Teichmueller Lie algebra

We show that the zeroth cohomology of M. Kontsevich's graph complex is isomorphic to the Grothendieck-Teichmueller Lie algebra grt_1. The map is explicitly described. This result has applications to deformation quantization and Duflo theory. We also compute the homotopy derivations of the Gerstenhaber operad. They are parameterized by grt_1, up to one class (or two, depending on the definitions). More generally, the homotopy derivations of the (non-unital) E_n operads may be expressed through the cohomology of a suitable graph complex. Our methods also give a second proof of a result of H. Furusho, stating that the pentagon equation for grt_1-elements implies the hexagon equation