A Group Signature Scheme Based on an RSA-Variant

The concept of group signatures allows a group member to sign messages anonymously on behalf of the group. However, in the case of a dispute, the identity of a signature’s originator can be revealed by a designated entity. In this paper we propose a new group signature scheme that is well suited for large groups, i.e., the length of the group’s public key and of signatures do notdepend on the size of the group. Our scheme is based on a variation of the RSA problem called strong RSA assumption. It is also more efficient than previous ones satisfying these requirements

Entwicklung eines Konzepts zur Quantifizierung der Nachfragestruktur und -entwicklung nach ökologisch erzeugten Produkten in Deutschland, unter Einbeziehung vorhandener Panel-Daten

Ziel des Projekts war es, Daten über produktspezifische Ausgaben nach Haushaltstypen, Regionen, Einkaufsstätten sowie über das Bio-Siegel zu erhalten. Dieses Ziel wurde erreicht. Durch eine kontinuierliche Berichterstattung über das Verbraucherverhalten über mehr als ein Jahr hinweg, konnten Schwachpunkte bisheriger Befragungen überwunden werden. Die im folgenden dargestellten Nachfragestrukturen beziehen sich auf den Zeitraum Oktober 2002 bis September 2003. • Die beiden wichtigsten Vertriebskanäle für Öko-Lebensmittel sind der Lebensmitteleinzelhandel (29%) und Naturkostfachgeschäfte (31%), aber auch die Erzeugervermarktung (16%) spielt im Vergleich zur konventionellen Ware eine bedeutende Rolle. • Die wichtigsten Produkte sind Molkereiprodukte, Gemüse/Salate, Brot/Backwaren und Getränke. • In Süddeutschland ist die Nachfrage stark über-, in Ostdeutschland stark unterproportional. • Die Kernzielgruppen sind Haushaltsführende mit hohem Bildungsniveau zwischen 35 und 44 Jahren (besonders wichtig für: Naturkostläden, Erzeuger, Frischmilch, Brotaufstriche) und zwischen 55 und 65 Jahren (besonders wichtig für: LEH, Reformhaus, O+G, Kartoffeln, Fleisch, Wurst und Käse). • Entscheidend für die Einkaufshäufigkeit von Lebensmitteln aus dem ökologischen Landbau sind Differenziale bei den folgenden Einstellungen: Höchste Zustimmung und hohe Diskriminierungskraft hat das Ernährungsbewusstsein gefolgt von Affinitäten für regionale Produkte, aktive Hinterfragung von möglichen Schadstoffbelastungen. Große Diskriminierungsfähigkeit hat auch die Zahlungsbereitschaft für hochwertige Lebensmittel. • Die Ergebnisse quantifizieren den Erfolg des Biosiegels. 43 % aller im Jahr 2003 getätigten Ausgaben für Öko-Produkte entfielen auf solche, die das Bio-Siegel trugen. Die Auslobung von Bio über dieses Zeichen wird vor allem vom LEH und insbesondere von den Drogeriemärkten genutzt: Bei letzteren entfielen 86 % aller Ausgaben auf Öko-Produkte mit dem staatlichen Zeichen

Contrastive Language-Image Pretrained (CLIP) Models are Powerful Out-of-Distribution Detectors

We present a comprehensive experimental study on pretrained feature extractors for visual out-of-distribution (OOD) detection. We examine several setups, based on the availability of labels or image captions and using different combinations of in- and out-distributions. Intriguingly, we find that (i) contrastive language-image pretrained models achieve state-of-the-art unsupervised out-of-distribution performance using nearest neighbors feature similarity as the OOD detection score, (ii) supervised state-of-the-art OOD detection performance can be obtained without in-distribution fine-tuning, (iii) even top-performing billion-scale vision transformers trained with natural language supervision fail at detecting adversarially manipulated OOD images. Finally, we argue whether new benchmarks for visual anomaly detection are needed based on our experiments. Using the largest publicly available vision transformer, we achieve state-of-the-art performance across all $18$ reported OOD benchmarks, including an AUROC of 87.6\% (9.2\% gain, unsupervised) and 97.4\% (1.2\% gain, supervised) for the challenging task of CIFAR100 $\rightarrow$ CIFAR10 OOD detection. The code will be open-sourced

Exploring the Limits of Deep Image Clustering using Pretrained Models

We present a general methodology that learns to classify images without labels by leveraging pretrained feature extractors. Our approach involves self-distillation training of clustering heads, based on the fact that nearest neighbors in the pretrained feature space are likely to share the same label. We propose a novel objective to learn associations between images by introducing a variant of pointwise mutual information together with instance weighting. We demonstrate that the proposed objective is able to attenuate the effect of false positive pairs while efficiently exploiting the structure in the pretrained feature space. As a result, we improve the clustering accuracy over $k$-means on $17$ different pretrained models by $6.1$\% and $12.2$\% on ImageNet and CIFAR100, respectively. Finally, using self-supervised pretrained vision transformers we push the clustering accuracy on ImageNet to $61.6$\%. The code will be open-sourced

Mediastinal goiter diagnosed by functional imaging

A 63-year-old asymptomatic woman with cured Hodgkin diseases presented for restaging. The chest computed tomography showed a mass at the right side of the upper mediastinum. The benignity and the origin of the tissue were unknown. First, we performed a bronchoscopy-guided biopsy but without success. In the next step, we initiated radionuclide imaging with technetium-99m pertechnetate (Tc-99m) and radioiodine (I-123). Low uptake of Tc-99m and intense accumulation of I-123 after 2 and 24 h to the mediastinal mass suggested that the mass was a mediastinal goiter. Based on iodine uptake and the fact that our patient had no symptoms of tracheal compression, we decide to go for a radioiodine therapy

Interaction of the Psychiatric Risk Gene Cacna1c With Post-weaning Social Isolation or Environmental Enrichment Does Not Affect Brain Mitochondrial Bioenergetics in Rats

The pathophysiology of neuropsychiatric disorders involves complex interactions between genetic and environmental risk factors. Confirmed by several genome-wide association studies, Cacna1c represents one of the most robustly replicated psychiatric risk genes. Besides genetic predispositions, environmental stress such as childhood maltreatment also contributes to enhanced disease vulnerability. Both, Cacna1c gene variants and stressful life events are associated with morphological alterations in the prefrontal cortex and the hippocampus. Emerging evidence suggests impaired mitochondrial bioenergetics as a possible underlying mechanism of these regional brain abnormalities. In the present study, we simulated the interaction of psychiatric disease-relevant genetic and environmental factors in rodents to investigate their potential effect on brain mitochondrial function using a constitutive heterozygous Cacna1c rat model in combination with a four-week exposure to either post-weaning social isolation, standard housing, or social and physical environmental enrichment. Mitochondria were isolated from the prefrontal cortex and the hippocampus to evaluate their bioenergetics, membrane potential, reactive oxygen species production, and respiratory chain complex protein levels. None of these parameters were considerably affected in this particular gene-environment setting. These negative results were very robust in all tested conditions demonstrating that Cacna1c depletion did not significantly translate into altered bioenergetic characteristics. Thus, further investigations are required to determine the disease-related effects on brain mitochondria

Free Fatty Acids in Bone Pathophysiology of Rheumatic Diseases

Obesity—in which free fatty acid (FFA) levels are chronically elevated—is a known risk factor for different rheumatic diseases, and obese patients are more likely to develop osteoarthritis (OA) also in non-weight-bearing joints. These findings suggest that FFA may also play a role in inflammation-related joint damage and bone loss in rheumatoid arthritis (RA) and OA. Therefore, the objective of this study was to analyze if and how FFA influence cells of bone metabolism in rheumatic diseases. When stimulated with FFA, osteoblasts from RA and OA patients secreted higher amounts of the proinflammatory cytokine interleukin (IL)-6 and the chemokines IL-8, growth-related oncogene α, and monocyte chemotactic protein 1. Receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin, and osteoblast differentiation markers were not influenced by FFA. Mineralization activity of osteoblasts correlated inversely with the level of FFA-induced IL-6 secretion. Expression of the Wnt signaling molecules, axin-2 and β-catenin, was not changed by palmitic acid (PA) or linoleic acid (LA), suggesting no involvement of the Wnt signaling pathway in FFA signaling for osteoblasts. On the other hand, Toll-like receptor 4 blockade significantly reduced PA-induced IL-8 secretion by osteoblasts, while blocking Toll-like receptor 2 had no effect. In osteoclasts, IL-8 secretion was enhanced by PA and LA particularly at the earliest time point of differentiation. Differences were observed between the responses of RA and OA osteoclasts. FFA might therefore represent a new molecular factor by which adipose tissue contributes to subchondral bone damage in RA and OA. In this context, their mechanisms of action appear to be dependent on inflammation and innate immune system rather than Wnt-RANKL pathways

Functional connectivity and amplitude of low-frequency fluctuations changes in people with complete subacute and chronic spinal cord injury.

After spinal cord injury (SCI), reorganization processes and changes in brain connectivity occur. Besides the sensorimotor cortex, the subcortical areas are strongly involved in motion and executive control. This exploratory study focusses on the cerebellum and vermis. Resting-state functional magnetic resonance imaging (fMRI) was performed. Between-group differences were computed using analysis of covariance and post-hoc tests for the seed-based connectivity measure with vermis and cerebellum as regions of interest. Twenty participants with complete SCI (five subacute SCI, 15 with chronic SCI) and 14 healthy controls (HC) were included. Functional connectivity (FC) was lower in all subjects with SCI compared with HC in vermis IX, right superior frontal gyrus (pFDR = 0.008) and right lateral occipital cortex (pFDR = 0.036). In addition, functional connectivity was lower in participants with chronic SCI compared with subacute SCI in bilateral cerebellar crus I, left precentral- and middle frontal gyrus (pFDR = 0.001). Furthermore, higher amplitude of low-frequency fluctuations (ALFF) was found in the left thalamus in individuals with subacute SCI (pFDR = 0.002). Reduced FC in SCI indicates adaptation with associated deficit in sensory and motor function. The increased ALFF in subacute SCI might reflect reorganization processes in the subacute phase