Security of quantum key distribution with iterative sifting

Several quantum key distribution (QKD) protocols employ iterative sifting. After each quantum transmission round, Alice and Bob disclose part of their setting information (including their basis choices) for the detected signals. The quantum phase of the protocol then ends when the numbers of detected signals per basis exceed certain pre-agreed threshold values. Recently, however, Pfister et al. [New J. Phys. 18 053001 (2016)] showed that iterative sifting makes QKD insecure, especially in the finite key regime, if the parameter estimation for privacy amplification uses the random sampling theory. This implies that a number of existing finite key security proofs could be flawed and cannot guarantee security. Here, we solve this serious problem by showing that the use of Azuma's inequality for parameter estimation makes QKD with iterative sifting secure again. This means that the existing protocols whose security proof employs this inequality remain secure even if they employ iterative sifting. Also, our results highlight a fundamental difference between the random sampling theorem and Azuma's inequality in proving security.Comment: 9 pages. We have found a flaw in the first version, which we have corrected in the revised versio

Tobacco Induced Priapism in Wister Rat: A Case Report

In an eight-week study on the effect of potash-tobacco dust ingestion on rats, a persistent penile erection for days was observed amongst some of the rats under study. This study involved a total of 42 Wister rats of weights rangingbetween 150-300g and grouped into four groups (A, B, C and D). Group A served as control, while groups B – Dserved as test groups and received 2g, 4g, and 6g of tobacco-dust, as well as 0.4g, 0.8g, and 1.2g of potash respectively, with water given ad libitum. By the 4th week, a persistent penile erection was observed in one of the rats in group C, and by the 6th week, a similar incident occurred in group C and D respectively, prompting serial observation. By the 8 week, gangrenous changes were observed, followed by necrosis and death of the rats on the 10th day from onset. The control rats (group A), which received normal feed and water, remained normal.Keywords: Priapism, Rat, Tobacco, Potash, Penile erectio

Tobacco Induced Renal Function Alterations in Wistar Rats: An 8 Weeks Study

This study investigates the effect of tobacco snuff on renal function using Wistar rat as a model. It involved adult rats (n=42) weighing 150-300g. They were assigned into a control group (A; n=6) and test groups B (n=12), C (n=12) and D (n=12). The groups were further divided into subgroups (1, 2, 3 and 4) representing durations of 2, 4, 6 and 8 weeks respectively. The test groups were fed varying doses of tobacco snuff  (tobacco plus potash).  At  the  end of every 2 weeks, three  randomly  selected rats were prepared for blood sample collection into lithium  heparin containers for laboratory analysis of creatinine, urea and uric acid. Results showed that creatinine levels of the  testrats were higher than the control, but the recorded values were however, duration dependent. Interestingly, a similar but irregular pattern was observed for urea and uric acid levels. Over all, the significant increase (P<0.05) in renal function parameters of the test rats (as compared to the control values), suggests that the ingestion of tobacco snuff has harmful effects on kidney functions.Keywords: Tobacco, Snuff, Kidney function, Nicotine substitute

Security of distributed-phase-reference quantum key distribution

Distributed-phase-reference quantum key distribution stands out for its easy implementation with present day technology. Since many years, a full security proof of these schemes in a realistic setting has been elusive. For the first time, we solve this long standing problem and present a generic method to prove the security of such protocols against general attacks. To illustrate our result we provide lower bounds on the key generation rate of a variant of the coherent-one-way quantum key distribution protocol. In contrast to standard predictions, it appears to scale quadratically with the system transmittance.Comment: 4 pages + appendix, 4 figure

The Effect of Tobacco Snuff Consumption on Liver Enzymes

This study was designed to investigate the changes in liver biochemical profile following oral tobacco dust ingestion. Adult Wistar rats (42) weighing 150-300g were involved. They were divided into four groups; group A serving as control, while groups B, C and D served as the test groups. The test groups were further divided into four groups (B1, C1, D1; B2, C2, D2; B3, C3, D3; and B4, C4, D4) representing four experimental phases/duration of 2, 4, 6 and 8 weeks respectively. The rats were fed with varying doses of tobacco dust mixed with potash. At the end of each phase, the animals were sacrificed and blood sample collected into lithium heparin and EDTA containers. Liver parameters (AST, ALT, ALP and GGT) were assayed and the results obtained showed statistically significant impairment of liver function. There was significant increase (p<0.05) in serum AST, ALT, and GGT levels in the different phases when the test groups were compared with the control. However, ALP shows no statistically significant increase in all the groups throughout the experiment. The results of this study suggest that potash-tobacco dust (local tobacco snuff) is toxic to the liver and the observed changes were dose and duration dependent.Keywords: tobacco, potash, liver function, liver enzymes

Deletion of the GABAA α2-subunit does not alter self dministration of cocaine or reinstatement of cocaine seeking

Rationale GABAA receptors containing α2-subunits are highly represented in brain areas that are involved in motivation and reward, and have been associated with addiction to several drugs, including cocaine. We have shown previously that a deletion of the α2-subunit results in an absence of sensitisation to cocaine. Objective We investigated the reinforcing properties of cocaine in GABAA α2-subunit knockout (KO) mice using an intravenous self-administration procedure. Methods α2-subunit wildtype (WT), heterozygous (HT) and KO mice were trained to lever press for a 30 % condensed milk solution. After implantation with a jugular catheter, mice were trained to lever press for cocaine (0.5 mg/kg/infusion) during ten daily sessions. Responding was extinguished and the mice tested for cue- and cocaine-primed reinstatement. Separate groups of mice were trained to respond for decreasing doses of cocaine (0.25, 0.125, 0.06 and 0.03 mg/kg). Results No differences were found in acquisition of lever pressing for milk. All genotypes acquired self-administration of cocaine and did not differ in rates of self-administration, dose dependency or reinstatement. However, whilst WT and HT mice showed a dose-dependent increase in lever pressing during the cue presentation, KO mice did not. Conclusions Despite a reported absence of sensitisation, motivation to obtain cocaine remains unchanged in KO and HT mice. Reinstatement of cocaine seeking by cocaine and cocaine-paired cues is also unaffected. We postulate that whilst not directly involved in reward perception, the α2-subunit may be involved in modulating the “energising” aspect of cocaine’s effects on reward-seeking

Quantitative trait locus analysis of hybrid pedigrees: variance-components model, inbreeding parameter, and power

<p>Abstract</p> <p>Background</p> <p>For the last years reliable mapping of quantitative trait loci (QTLs) has become feasible through linkage analysis based on the variance-components method. There are now many approaches to the QTL analysis of various types of crosses within one population (breed) as well as crosses between divergent populations (breeds). However, to analyse a complex pedigree with dominance and inbreeding, when the pedigree's founders have an inter-population (hybrid) origin, it is necessary to develop a high-powered method taking into account these features of the pedigree.</p> <p>Results</p> <p>We offer a universal approach to QTL analysis of complex pedigrees descended from crosses between outbred parental lines with different QTL allele frequencies. This approach improves the established variance-components method due to the consideration of the genetic effect conditioned by inter-population origin and inbreeding of individuals. To estimate model parameters, namely additive and dominant effects, and the allelic frequencies of the QTL analysed, and also to define the QTL positions on a chromosome with respect to genotyped markers, we used the maximum-likelihood method. To detect linkage between the QTL and the markers we propose statistics with a non-central χ²-distribution that provides the possibility to deduce analytical expressions for the power of the method and therefore, to estimate the pedigree's size required for 80% power. The method works for arbitrarily structured pedigrees with dominance and inbreeding.</p> <p>Conclusion</p> <p>Our method uses the phenotypic values and the marker information for each individual of the pedigree under observation as initial data and can be valuable for fine mapping purposes. The power of the method is increased if the QTL effects conditioned by inter-population origin and inbreeding are enhanced. Several improvements can be developed to take into account fixed factors affecting trait formation, such as age and sex.</p

WNT signaling regulates self-renewal and differentiation of prostate cancer cells with stem cell characteristics

Prostate cancer cells with stem cell characteristics were identified in human prostate cancer cell lines by their ability to form from single cells self-renewing prostaspheres in non-adherent cultures. Prostaspheres exhibited heterogeneous expression of proliferation, differentiation and stem cell-associated makers CD44, ABCG2 and CD133. Treatment with WNT inhibitors reduced both prostasphere size and self-renewal. In contrast, addition of Wnt3a caused increased prostasphere size and self-renewal, which was associated with a significant increase in nuclear Β-catenin, keratin 18, CD133 and CD44 expression. As a high proportion of LNCaP and C4-2B cancer cells express androgen receptor we determined the effect of the androgen receptor antagonist bicalutamide. Androgen receptor inhibition reduced prostasphere size and expression of PSA, but did not inhibit prostasphere formation. These effects are consistent with the androgen-independent self-renewal of cells with stem cell characteristics and the androgen-dependent proliferation of transit amplifying cells. As the canonical WNT signaling effector Β-catenin can also associate with the androgen receptor, we propose a model for tumour propagation involving a balance between WNT and androgen receptor activity. That would affect the self-renewal of a cancer cell with stem cell characteristics and drive transit amplifying cell proliferation and differentiation. In conclusion, we provide evidence that WNT activity regulates the self-renewal of prostate cancer cells with stem cell characteristics independently of androgen receptor activity. Inhibition of WNT signaling therefore has the potential to reduce the self-renewal of prostate cancer cells with stem cell characteristics and improve the therapeutic outcome.Peer reviewe