The Complexity of Reasoning for Fragments of Default Logic

Default logic was introduced by Reiter in 1980. In 1992, Gottlob classified the complexity of the extension existence problem for propositional default logic as \SigmaPtwo-complete, and the complexity of the credulous and skeptical reasoning problem as SigmaP2-complete, resp. PiP2-complete. Additionally, he investigated restrictions on the default rules, i.e., semi-normal default rules. Selman made in 1992 a similar approach with disjunction-free and unary default rules. In this paper we systematically restrict the set of allowed propositional connectives. We give a complete complexity classification for all sets of Boolean functions in the meaning of Post's lattice for all three common decision problems for propositional default logic. We show that the complexity is a hexachotomy (SigmaP2-, DeltaP2-, NP-, P-, NL-complete, trivial) for the extension existence problem, while for the credulous and skeptical reasoning problem we obtain similar classifications without trivial cases.Comment: Corrected versio

Oxazepam and temazepam attenuate paroxetine-induced elevation of serotonin levels in guinea-pig hippocampus

Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are used as a first-line treatment in depression. However, many depressed patients are also treated with benzodiazepines to alleviate increased anxiety and sleep disturbances normally associated with depression. Since benzodiazepines inhibit 5-HT neuronal firing activity, they might attenuate SSRI-induced increase in extracellular 5-HT levels. This study aimed to assess, using in-vivo microdialysis, the effects of the benzodiazepines oxazepam or temazepan on the SSRI paroxetine-induced 5-HT increase in the hippocampus of freely moving guinea-pigs. It was found that the acute systemic administration of paroxetine increased extracellular 5-HT levels. Pre-administration of oxazepam or temazepam significantly diminished the paroxetine-induced elevation of extracellular 5-HT levels (from 350% to 200% of baseline). It was concluded that benzodiazepines attenuate the ability of SSRIs to elevate hippocampal 5-HT levels. Thus, co-administration of benzodiazepines might affect the therapeutic efficacy of SSRI treatment

High-resolution microwave frequency dissemination on an 86-km urban optical link

We report the first demonstration of a long-distance ultra stable frequency dissemination in the microwave range. A 9.15 GHz signal is transferred through a 86-km urban optical link with a fractional frequency stability of 1.3x10-15 at 1 s integration time and below 10-18 at one day. The optical link phase noise compensation is performed with a round-trip method. To achieve such a result we implement light polarisation scrambling and dispersion compensation. This link outperforms all the previous radiofrequency links and compares well with recently demonstrated full optical links.Comment: 11 pages, 5 figure

Correlations in Transmission of Light through a Disordered Amplifying Medium

The angular and frequency correlation functions of the transmission coefficient for light propagation through a strongly scattering amplifying medium are considered. It is found that just as in the case of an elastic scattering medium the correlation function consists of three terms. However, the structure of the terms is rather different. Angular correlation has a power-law decay and exhibits oscillations. There is no "memory effect" as in the case of an elastic medium. Interaction between diffusion modes is strongly enhanced near the lasing threshold. Frequency correlation scale decreases close to the lasing threshold. We also consider time correlations of the transmission in the case of nonstationary inhomogeneities. We find short- and long-range time correlations. The scale of the short-range correlation decreases, while the long-range correlation scale becomes infinite near the threshold.Comment: 16 pages, 7 postscript figure

Characterization of Liposomes for Cancer Cell Transfection

We have characterized a broad range of liposome formulations with varying DcChol:DOPE ratio. Subsequent addition of DcChol to liposomes increases its positive surface charge. However, loading the nuclear acids did not neutralize the overall negative surface potential to a similar extent. The liposomes were tested by transfection of DNA in living cancer cells

Do Stress Responses Promote Leukemia Progression? An Animal Study Suggesting a Role for Epinephrine and Prostaglandin-E2 through Reduced NK Activity

In leukemia patients, stress and anxiety were suggested to predict poorer prognosis. Oncological patients experience ample physiological and psychological stress, potentially leading to increased secretion of stress factors, including epinephrine, corticosteroids, and prostaglandins. Here we tested whether environmental stress and these stress factors impact survival of leukemia-challenged rats, and studied mediating mechanisms. F344 rats were administered with a miniscule dose of 60 CRNK-16 leukemia cells, and were subjected to intermittent forced swim stress or to administration of physiologically relevant doses of epinephrine, prostaglandin-E2 or corticosterone. Stress and each stress factor, and/or their combinations, doubled mortality rates when acutely applied simultaneously with, or two or six days after tumor challenge. Acute administration of the β-adrenergic blocker nadolol diminished the effects of environmental stress, without affecting baseline survival rates. Prolonged β-adrenergic blockade or COX inhibition (using etodolac) also increased baseline survival rates, possibly by blocking tumor-related or normal levels of catecholamines and prostaglandins. Searching for mediating mechanisms, we found that each of the stress factors transiently suppressed NK activity against CRNK-16 and YAC-1 lines on a per NK basis. In contrast, the direct effects of stress factors on CRNK-16 proliferation, vitality, and VEGF secretion could not explain or even contradicted the in vivo survival findings. Overall, it seems that environmental stress, epinephrine, and prostaglandins promote leukemia progression in rats, potentially through suppressing cell mediated immunity. Thus, patients with hematological malignancies, which often exhibit diminished NK activity, may benefit from extended β-blockade and COX inhibition

Genome-wide characterization of copy number variations in the host genome in genetic resistance to Marek’s disease using next generation sequencing

Marek’s disease (MD) is a highly neoplastic disease primarily affecting chickens, and remains as a chronic infectious disease that threatens the poultry industry. Copy number variation (CNV) has been examined in many species and is recognized as a major source of genetic variation that directly contributes to phenotypic variation such as resistance to infectious diseases. Two highly inbred chicken lines, 63 (MD-resistant) and 72 (MD-susceptible), as well as their F1 generation and six recombinant congenic strains (RCSs) with varied susceptibility to MD, are considered as ideal models to identify the complex mechanisms of genetic and molecular resistance to MD. In the present study, to unravel the potential genetic mechanisms underlying resistance to MD, we performed a genome-wide CNV detection using next generation sequencing on the inbred chicken lines with the assistance of CNVnator. As a result, a total of 1649 CNV regions (CNVRs) were successfully identified after merging all the nine datasets, of which 90 CNVRs were overlapped across all the chicken lines. Within these shared regions, 1360 harbored genes were identified. In addition, 55 and 44 CNVRs with 62 and 57 harbored genes were specifically identified in line 63 and 72, respectively. Bioinformatics analysis showed that the nearby genes were significantly enriched in 36 GO terms and 6 KEGG pathways including JAK/STAT signaling pathway. Ten CNVRs (nine deletions and one duplication) involved in 10 disease-related genes were selected for validation by using quantitative real-time PCR (qPCR), all of which were successfully confirmed. Finally, qPCR was also used to validate two deletion events in line 72 that were definitely normal in line 63. One high-confidence gene, IRF2 was identified as the most promising candidate gene underlying resistance and susceptibility to MD in view of its function and overlaps with data from previous study. Our findings provide valuable insights for understanding the genetic mechanism of resistance to MD and the identified gene and pathway could be considered as the subject of further functional characterization.https://doi.org/10.1186/s12863-020-00884-

Opportunities for high-energy neutron- and deuteron-induced measurements for fusion technology at the Soreq applied research accelerator facility (SARAF)

The Soreq Applied Research Accelerator Facility (SARAF) will be based on a 40 MeV, 5 mA CW (continuous wave) proton/deuteron superconducting linear accelerator, currently under construction at Soreq Nuclear Research Center in Yavne, Israel. It is planned to commence operation during 2025. Experiments at SARAF could provide data on high-energy deuteron- and neutron-induced cross-sections, yields and radiation damage, which are invaluable for the design and operation of the International Fusion Materials Irradiation Facility-DEMO-Oriented NEutron Source (IFMIF-DONES), and fusion technology in general. Pulsed beams (∼1 nsec) of variable energy deuterons will irradiate a lithium target and generate pulsed neutron beams with energy up to ∼55 MeV, which will be used to measure energy-dependent neutron-induced differential cross-sections, utilizing time of flight techniques. Impinging continuous wave (CW) 40 MeV deuteron beams on a unique gallium-indium (GaIn) liquid-jet target, will generate a neutron rate of more than 1 × 1015 n/sec, with energies up to ∼45 MeV. We plan to use this high rate to measure integral neutron-induced reaction yields of all channels simultaneously, employing an original novel method that will identify the reaction-produced nuclei via accurate mass measurement. The neutron-energy dependence of the yields could be deduced by combining measurements at various deuteron energies. The measured cross-sections and yields at SARAF may predict the activation characteristics of construction materials of IFMIF-DONES and future fusion reactors. The deuteron beams will also be used directly to measure cross-sections via in-beam and offline methods. The high neutron and deuteron rates will extend SARAF’s reach to rare materials. The deuteron beam power density on the liquid GaIn target will be 100 kW/cm2 (similar to IFMIF-DONES) on a 2 cm2 spot. The resulting neutron flux on small secondary samples will be in the 1013 n/cm2/s level, only an order of magnitude less than IFMIF-DONES. Therefore, SARAF may serve as a pilot facility for fusion-related radiation damage studies, providing important information towards the design of IFMIF-DONES