884 research outputs found
From sea to land and beyond : new insights into the evolution of euthyneuran Gastropoda (Mollusca)
Background The Euthyneura are considered to be the most successful and diverse group of Gastropoda. Phylogenetically, they are riven with controversy. Previous morphology-based phylogenetic studies have been greatly hampered by rampant parallelism in morphological characters or by incomplete taxon sampling. Based on sequences of nuclear 18S rRNA and 28S rRNA as well as mitochondrial 16S rRNA and COI DNA from 56 taxa, we reconstructed the phylogeny of Euthyneura utilising Maximum Likelihood and Bayesian inference methods. The evolution of colonization of freshwater and terrestrial habitats by pulmonate Euthyneura, considered crucial in the evolution of this group of Gastropoda, is reconstructed with Bayesian approaches. Results We found several well supported clades within Euthyneura, however, we could not confirm the traditional classification, since Pulmonata are paraphyletic and Opistobranchia are either polyphyletic or paraphyletic with several clades clearly distinguishable. Sacoglossa appear separately from the rest of the Opisthobranchia as sister taxon to basal Pulmonata. Within Pulmonata, Basommatophora are paraphyletic and Hygrophila and Eupulmonata form monophyletic clades. Pyramidelloidea are placed within Euthyneura rendering the Euthyneura paraphyletic. Conclusion Based on the current phylogeny, it can be proposed for the first time that invasion of freshwater by Pulmonata is a unique evolutionary event and has taken place directly from the marine environment via an aquatic pathway. The origin of colonisation of terrestrial habitats is seeded in marginal zones and has probably occurred via estuaries or semi-terrestrial habitats such as mangroves
Pricing of Cyber Insurance Contracts in a Network Model
We develop a novel approach for pricing cyber insurance contracts. The considered cyber threats, such as viruses and worms, diffuse in a structured data network. The spread of the cyber infection is modeled by an interacting Markov chain. Conditional on the underlying infection, the occurrence and size of claims are described by a marked point process. We introduce and analyze a new polynomial approximation of claims together with a mean-field approach that allows to compute aggregate expected losses and prices of cyber insurance. Numerical case studies demonstrate the impact of the network topology and indicate that higher order approximations are indispensable for the analysis of non-linear claims. © 2018 by Astin Bulletin. All rights reserved
Different Outcomes of Experimental Hepatitis E Virus Infection in Diverse Mouse Strains, Wistar Rats, and Rabbits
Hepatitis E virus (HEV) is the causative agent of acute hepatitis E in humans in developing countries, but autochthonous cases of zoonotic genotype 3 (HEV-3) infection also occur in industrialized countries. In contrast to swine, rats, and rabbits, natural HEV infections in mice have not yet been demonstrated. The pig represents a well-established large animal model for HEV-3 infection, but a suitable small animal model mimicking natural HEV-3 infection is currently missing. Therefore, we experimentally inoculated C57BL/6 mice (wild-type, IFNAR−/−, CD4−/−, CD8−/−) and BALB/c nude (nu/nu) mice, Wistar rats, and European rabbits with a wild boar-derived HEV-3 strain and monitored virus replication and shedding, as well as humoral immune responses. HEV RNA and anti-HEV antibodies were detected in one and two out of eight of the rats and all rabbits inoculated, respectively, but not in any of the mouse strains tested. Remarkably, immunosuppressive dexamethasone treatment of rats did not enhance their susceptibility to HEV infection. In rabbits, immunization with recombinant HEV-3 and ratHEV capsid proteins induced protection against HEV-3 challenge. In conclusion, the rabbit model for HEV-3 infection may serve as a suitable alternative to the non-human primate and swine models, and as an appropriate basis for vaccine evaluation studies
Harnessing spatial homogeneity of neuroimaging data: patch individual filter layers for CNNs
Neuroimaging data, e.g. obtained from magnetic resonance imaging (MRI), is
comparably homogeneous due to (1) the uniform structure of the brain and (2)
additional efforts to spatially normalize the data to a standard template using
linear and non-linear transformations. Convolutional neural networks (CNNs), in
contrast, have been specifically designed for highly heterogeneous data, such
as natural images, by sliding convolutional filters over different positions in
an image. Here, we suggest a new CNN architecture that combines the idea of
hierarchical abstraction in neural networks with a prior on the spatial
homogeneity of neuroimaging data: Whereas early layers are trained globally
using standard convolutional layers, we introduce for higher, more abstract
layers patch individual filters (PIF). By learning filters in individual image
regions (patches) without sharing weights, PIF layers can learn abstract
features faster and with fewer samples. We thoroughly evaluated PIF layers for
three different tasks and data sets, namely sex classification on UK Biobank
data, Alzheimer's disease detection on ADNI data and multiple sclerosis
detection on private hospital data. We demonstrate that CNNs using PIF layers
result in higher accuracies, especially in low sample size settings, and need
fewer training epochs for convergence. To the best of our knowledge, this is
the first study which introduces a prior on brain MRI for CNN learning
Comparing validation of four ELISAsystems for detection of Salmonella Derby- and Salmonella Infantis-infected pigs
The objective of this study was the comparative evaluation of four indirect
Salmonella ELISA tests at study time approved in Germany to detect Salmonella
infection in pigs. Three tests are based on a LPS-antigen mix and directed
against specific IgG antibodies. The fourth test is based on a purified S.
Typhimurium whole-cell lysate antigen and discriminates between Salmonella-
specific IgM-, IgA-, and IgG- antibodies. In a longitudinal study, two groups
of six weeks old hybrid piglets were orally infected with a porcine S.
Infantis or S. Derby strain. Clinical and bacteriological parameters were
monitored weekly during an observation period of 130 days after infection and
serum samples were investigated in parallel with the respective ELISAs.
Apparently, the LPS-based ELISA systems used in this study failed to recognize
S. Infantis-infected pigs although those animals shed the pathogen in high
amounts throughout the study until day 81 post infection (p. i.). In contrast,
the isotype-specific Salmonella Typhimurium whole-cell-lysate based ELISA was
capable of detecting Salmonella-infected pigs from day ten p. i. at all tested
serotypes and revealed the highest sensitivity in detection of S. Infantis-
infected pigs. Furthermore, it became apparent that the often used
surveillance cut-off value of 40 OD% is not appropriate for intra-vitam
detection of S. Infantis- and S. Derbyinfected pigs. In contrast, the cut-off
values of the ELISAs given by the suppliers result in considerable higher
detection rates
Reconciling the control of the native invasive Jacobaea aquatica and ecosystem multifunctionality in wet grasslands
Grasslands are managed to provide multiple goods and services. During recent decades, abandonment of marginal grasslands and intensification of the most productive sites resulted in biodiversity losses and reduced ecosystem services (ESs). Moreover, invasion by unwanted plants impaired ESs, as seen in Jacobaea aquatica, a poisonous native invader in pre-alpine grasslands of Central Europe. Invasion by this plant compromises fodder quality and endangers animal health, resulting in abandonment of grassland use. We tested different management regimes to reduce J. aquatica in wet grasslands of Southern Germany and assessed how its regulation affects grassland multifunctionality. We monitored indicators associated with productivity and conservation, such as the abundance of J. aquatica, forage quality, yield, abundance of specialists, and pollinator-relevant plants. Intensive management favoured multifunctionality by promoting productivity and biodiversity, yet also increasing the abundance of J. aquatica. Reduced management regulates J. aquatica cover close to an acceptable threshold while also reducing ESs. Thus, we conclude that moderate management strikes a balance between the control of the poisonous plant and the supply of grassland multifunctionality.publishedVersio
Pathogen Screening for Possible Causes of Meningitis/Encephalitis in Wild Carnivores From Saxony-Anhalt
Inflammation in meninges and/or brain is regularly noticed in red foxes and other wild
carnivores during rabies control programs. Despite negative rabies virus (RABV) results,
the etiologies of these cases remain unknown. Thus, the aim of this study was to provide
an overview of the occurrence of pathogens that may cause diseases in the brains of
wild carnivores and pose a risk to humans and other animals. In addition to RABV and
canine distemper virus (CDV), a variety of pathogens, including members of Flaviviridae,
Bornaviridae, Herpesviridae, Circoviridae, as well as bacteria and parasites can also
cause brain lesions. In 2016 and 2017, brain samples of 1,124 wild carnivores were
examined by direct fluorescent antibody test for RABV as well as (reverse-transcriptase)
quantitative polymerase chain reaction (PCR) for the presence of CDV as part of a
monitoring program in Saxony-Anhalt, Germany. Here, we applied similar methods to
specifically detect suid herpesvirus 1 (SuHV-1), West Nile virus (WNV), Borna disease
virus 1 (BoDV-1), canid alphaherpesvirus 1 (CaHV-1), canine parvovirus type 2 (CPV-2),
fox circovirus (FoxCV), and Neospora caninum (N. caninum). Further, bacteriogical
examination for the existence of Listeria monocytogenes (L. monocytogenes) and
immunohistochemistry of selected cases to detect Toxoplasma gondii (T. gondii) antigen
were performed. Of all pathogens studied, CDV was found most frequently (31.05%),
followed by FoxCV (6.80%), CPV-2 (6.41%), T. gondii (4/15; 26.67%), nematode larvae
(1.51%), L. monocytogenes (0.3%), and various other bacterial pathogens (1.42%). In 68
of these cases (6.05%), multiple pathogen combinations were present simultaneously.
However, RABV, WNV, BoDV-1, SuHV-1, CaHV-1, and N. caninum were not detected.
The majority of the histopathological changes in 440 animals were inflammation
(320/440; 72.73%), predominantly non-suppurative in character (280/320; 87.50%), and
in many cases in combination with gliosis, satellitosis, neuronophagia, neuronal necrosis,
and/or vacuolization/demyelination, or in single cases with malacia. Thus, it could be
shown that wild carnivores in Saxony-Anhalt are carriers mainly for CDV and sometimes
also for other, partly zoonotic pathogens. Therefore, the existing monitoring program
should be expanded to assess the spill-over risk from wild carnivores to humans and
other animals and to demonstrate the role of wild carnivores in the epidemiology of these
zoonotic pathogens
Long-Term Relapse-Free Survival by Interdisciplinary Collaboration in a Patient with Metastatic Pancreatic Cancer (UICC IV)
Introduction: The prognostic outlook for patients suffering from pancreatic cancer is generally poor. Particularly in cases of advanced and metastatic disease, long-term relapse-free survival may be achieved only in a few cases. Case Report: A 45-year-old patient presented with metastatic pancreatic cancer. Liver metastases had been intra-operatively confirmed by histology. Prior to initiating treatment, a portacath was surgically implanted. Subsequently, the patient received a weekly dose of 1,000 mg/m2 gemcitabine combined with 2,000 mg/m2 high-dose 5-fluorouracil as a 24-hour infusion for palliative treatment. As the patient was suffering from a stenosis of the ductus hepaticus communis, an endoprosthesis was primarily implanted. After 18 applications of chemotherapy during which only low toxic side effects such as nausea, vomiting and alopecia (NCI-CTC grade 1) presented, a partial remission of the primary tumor was observed. In the course of chemotherapy treatment, the carbohydrate antigen 19-9 tumor marker value normalized. Thus, the interdisciplinary tumor board of the University of Erlangen decided to perform a laparoscopy to evaluate the status of liver metastases after palliative chemotherapy treatment. Subsequently, the primary tumor could be completely resected (pT2, pN0, pM0, L0, V0, G2, R0); liver metastases were not observed. Eight years after the initial diagnosis, the patient is relapse-free, professionally fully integrated and presents with an excellent performance status. Conclusion: Patients suffering from metastatic pancreatic cancer may benefit from treatment combinations with palliative intent. In singular cases, patients may even have a curative treatment option, provided a close interdisciplinary collaboration exists
- …