On Leibniz cohomology

In this paper we prove the Leibniz analogue of Whitehead's vanishing theorem for the Chevalley-Eilenberg cohomology of Lie algebras. As a consequence, we obtain the second Whitehead lemma for Leibniz algebras. Moreover, we compute the cohomology of several Leibniz algebras with adjoint or irreducible coefficients. Our main tool is a Leibniz analogue of the Hochschild-Serre spectral sequence, which is an extension of (the dual of) a spectral sequence of Pirashvili for Leibniz homology from symmetric bimodules to arbitrary bimodules.Comment: We correct here an error in an earlier versio

Changes in sensory profile and microbiological quality during chill storage of cured and uncured cooked sliced emulsion-type sausages

Nine batches of cooked sliced emulsion type sausages, produced from organic meat with or without the use of nitrite, were packed under N2/CO2 (7:3) and vacuum, respectively, and stored at 8°C. During two weeks of storage, the microbiological quality was determined, as well as the sensory quality by using profile analysis. The spoilage flora consisted of lactic acid bacteria and Brochothrix thermosphacta, without clear evidence of an inhibitory effect of nitrite on the growth of these organisms. The sensory profile showed an increase of the sour and rancid aroma and flavour, in parallel to the growth of these microorganisms. These changes were more pronounced in the batches prepared without nitrite. Spots of red discolourations were occasionally observed during storage of uncured sausage slices. These may have been caused by reduction of traces of nitrate from spices by psychrotrophic Enterobacteriaceae

Electron Energy-Loss Spectroscopy: A versatile tool for the investigations of plasmonic excitations

The inelastic scattering of electrons is one route to study the vibrational and electronic properties of materials. Such experiments, also called electron energy-loss spectroscopy, are particularly useful for the investigation of the collective excitations in metals, the charge carrier plasmons. These plasmons are characterized by a specific dispersion (energy-momentum relationship), which contains information on the sometimes complex nature of the conduction electrons in topical materials. In this review we highlight the improvements of the electron energy-loss spectrometer in the last years, summarize current possibilities with this technique, and give examples where the investigation of the plasmon dispersion allows insight into the interplay of the conduction electrons with other degrees of freedom

ON LEIBNIZ COHOMOLOGY

In this paper we prove the Leibniz analogues of several vanishing theorems for the Chevalley-Eilenberg cohomology of Lie algebras. In particular , we obtain the second Whitehead lemma for Leibniz algebras. Our main tools are three spectral sequences. Two are Leibniz analogues of the Hochschild-Serre spectral sequence, one of which is an extension of the dual of a spectral sequence of Pirashvili for Leibniz homology from symmetric bi-modules to arbitrary bimodules, and the other one is due to Beaudouin. A third spectral sequence (also due to Pirashvili in homology) relates the Leibniz cohomology of a Lie algebra to its Chevalley-Eilenberg cohomology

SEMS vs cSEMS in duodenal and small bowel obstruction : high risk of migration in the covered stent group

Aim: To compare clinical success and complications of uncovered self-expanding metal stents (SEMS) vs covered SEMS (cSEMS) in obstruction of the small bowel. Methods: Technical success, complications and outcome of endoscopic SEMS or cSEMS placement in tumor related obstruction of the duodenum or jejunum were retrospectively assessed. The primary end points were rates of stent migration and overgrowth. Secondary end points were the effect of concomitant biliary drainage on migration rate and overall survival. The data was analyzed according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Results: Thirty-two SEMS were implanted in 20 patients. In all patients, endoscopic stent implantation was successful. Stent migration was observed in 9 of 16 cSEMS (56%) in comparison to 0/16 SEMS (0%) implantations (P = 0.002). Stent overgrowth did not significantly differ between the two stent types (SEMS: 3/16, 19%; cSEMS: 2/16, 13%). One cSEMS dislodged and had to be recovered from the jejunum by way of laparotomy. Time until migration between SEMS and cSEMS in patients with and without concomitant biliary stents did not significantly differ (HR = 1.530, 95%CI 0.731-6.306; P = 0.556). The mean follow-up was 57 ± 71 d (range: 1-275 d). Conclusion: SEMS and cSEMS placement is safe in small bowel tumor obstruction. However, cSEMS is accompanied with a high rate of migration in comparison to uncovered SEMS

Local twistors and the conformal field equations

This note establishes the connection between Friedrich's conformal field equations and the conformally invariant formalism of local twistors.Comment: LaTeX2e Minor corrections of misprints et

Serial stereotactic biopsy of brainstem lesions in adults improves diagnostic accuracy compared with MRI only.

Objective: The aim of the current prospective study was to analyse the validity of MRI based diagnosis of brainstem gliomas which was verified by stereotactic biopsy and follow-up evaluation as well as to assess prognostic factors and risk profile. Methods: Between 1998 and 2007, all consecutive adult patients with radiologically suspected brainstem glioma were included. The MRI based diagnosis of the lesions was made independently by an experienced neuroradiologist. Histopathological evaluation was performed in all patients from paraffin embedded specimens obtained by multimodal image guided stereotactic serial biopsy technique. Histopathological results were compared with prior radiological assessment. Length of survival was estimated with the Kaplan–Meier method and prognostic factors were calculated using the Cox model. Results: 46 adult patients were included. Histological evaluation revealed pilocytic astrocytoma (n=2), WHO grade II glioma (n=14), malignant glioma (n=12), metastasis (n=7), lymphoma (n=5), cavernoma (n=1), inflammatory disease (n=2) or no tumour/ gliosis (n=3). Perioperative morbidity was 2.5% (n=1). There was no permanent morbidity and no mortality. All patients with ‘‘no tumour’’ or ‘‘inflammatory disease’’ survived. Patients with low grade glioma and malignant glioma showed a 1 year survival rate of 75% and 25%, respectively; the 1 year survival rate for patients with lymphoma or metastasis was 30%. In the subgroup with a verified brainstem glioma, negative predictors for length of survival were higher tumour grade (p=0.002) and Karnofsky performance score (70 (p=0.004). Conclusion: Intra-axial brainstem lesions with a radiological pattern of glioma represent a very heterogeneous tumour group with completely different outcomes. Radiological features alone are not reliable for diagnostic classification. Stereotactic biopsy is a safe method to obtain a valid tissue diagnosis, which is indispensible for treatment decision

Integrating a Method for Achieving Activity-Oriented Sustainability into the Design Science Research Methodology

Sustainability increasingly becomes an effective argument in the public and academic discourse. However, in the scientific design process of IT artifacts, the notion of sustainability is often misused. IT artifacts and consequences resulting from their operation are characterized to be sustainable without truly reflecting the meaning of the characteristics of sustainability. By subscribing to a view of sustainability as a characteristic of an activity, we propose a method for the systematic integration of sustainability into the design of IT artifacts. Our so-called “activity-oriented sustainability method” is situated within the design science research methodology (DSRM) and allows to perform an ex-ante domain-specific sustainability analysis of activities, which are supported by an IT artifact. This article contributes to research and praxis by spurring discourse on the consideration of sustainability in design research endeavors and by providing a method for the systematic integration of sustainable activities into IT artifacts

Design Principles for Digital Community Currencies

Community currencies are alternative currencies, which enable the mobilization of local resources for local needs and building resilient communities. They allow community members to perform economic transactions like buying products and paying for services using an alternative currency as a medium of exchange. For decades, regional, paper-based community currencies have been in use across the world. With the advent of the digital age, community currencies are increasingly moving into the digital space. Digital Community Currencies (DCCs) create opportunities for addressing challenges that traditional community currencies are facing, such as the inconvenience of handling two currencies in one wallet and the geographic limitation to a limited user population. This research builds upon characteristics and challenges of community currencies and derives six design principles from a literature review, an analysis of 16 community currency projects and an interview with a community currency project manager at the end of the project’s life. The design principles serve as a basis for establishing resilient and scalable DCCs. They contribute to the limited IS research on phenomena of social sustainability and have major practical implications when implemented in existing community currency systems

Failure in generating hemopoietic stem cells is the primary cause of death from cytomegalovirus disease in the immunocompromised host

We have shown in a murine model system for cytomegalovirus (CMV) disease in the immunocompromised host that CMV infection interferes with the earliest detectable step in hemopoiesis, the generation of the stem cell CFU-S-I, and thereby prevents the autoreconstitution of bone marrow after sublethal irradiation. The antihemopoietic effect could not be ascribed to a direct infection of stem cells. The failure in hemopoiesis was prevented by adoptive transfer of antiviral CD8+ T lymphocytes and could be overcome by syngeneic bone marrow transplantation. CD8+ T lymphocytes and bone marrow cells both mediated survival, although only CD8+ T lymphocytes were able to limit virus multiplication in host tissues. We concluded that not the cytopathic effect of virus replication in host tissues, but the failure in hemopoiesis, is the primary cause of death in murine CMV disease