Weak coin flipping with small bias

This paper presents a quantum protocol that demonstrates that weak coin flipping with bias ≈0.239, less than 1/4, is possible. A bias of 1/4 was the smallest known, and followed from the strong coin flipping protocol of Ambainis in [33rd STOC, 2001] (also proposed by Spekkens and Rudolph [Phys. Rev. A 65 (2002) 012310]). Protocols with yet smaller bias ≈0.207 have independently been discovered by Ambainis (2001) and Spekkens and Rudolph [Phys. Rev. Lett. 89 (2002) 227901]. We also present an alternative strong coin flipping protocol with bias 1/4 with analysis simpler than that of Ambainis [33rd STOC, 2001].     

Quantum commitments from complexity assumptions

Bit commitment schemes are at the basis of modern cryptography. Since information-theoretic security is impossible both in the classical and in the quantum regime, we examine computationally secure commitment schemes. In this paper we study worst-case complexity assumptions that imply quantum bit commitment schemes. First, we show that QSZK \({\not\subseteq}\) QMA implies a computationally hiding and statistically binding auxiliary-input quantum commitment scheme. We then extend our result to show that the much weaker assumption QIP \({\not\subseteq}\) QMA (which is weaker than PSPACE \({\not\subseteq}\) PP) implies the existence of auxiliary-input commitment schemes with quantum advice. Finally, to strengthen the plausibility of the separation QSZK \({\not\subseteq}\) QMA, we find a quantum oracle relative to which honest-verifier QSZK is not contained in QCMA, the class of languages that can be verified using a classical proof in quantum polynomial time.     

Electrochemical reduction of thermally prepared oxides of iron and iron-chromium alloys studied by in situ Raman spectroscopy

Pure Fe and Fe/Cr alloys (3% and 12% Cr) were oxidized at 250–260°C and subsequently electrochemically reduced in borate buffer, pH 8.4. The reduction was followed by in situ Raman spectroscopy as well as chronopotentiometric and chronoamperometric measurements. At several time intervals ex situ Raman control investigations and ESCA analyses were undertaken. Although at −0.7 V vs sce partial reduction of the oxide film was observed, -Fe₂O₃ remained unchanged and reduced at −0.9 V. A mixture of spinel structured oxide, possibly Fe₃O₄, and a ferrous deposit were observed when the oxide film was galvanostatically reduced at 100 μA cm⁻²; after prolonged reduction the bare metal resulted. The thermally created oxide of the Cr alloy possessed an inner Cr rich layer which during the galvanostatic reduction of the oxide film at 50 μA cm⁻² is most likely responsible for an increase in the overpotential of more than 80 mV.     

Decidual Macrophages Are Significantly Increased in Spontaneous Miscarriages and Over-Express FasL: A Potential Role for Macrophages in Trophoblast Apoptosis

Decidual macrophages (DM) are the second most abundant population in the fetal-maternal interface. Their role has been so far identified as being local immuno-modulators favoring the maternal tolerance to the fetus. Herein we investigated tissue samples from 11 cases of spontaneous miscarriages and from 9 cases of elective terminations of pregnancy. Using immunohistochemistry and dual immunofluorescence we have demonstrated that in spontaneous miscarriages the DM are significantly increased. Additionally, we noted a significant up-regulation of macrophage FasL expression. Our results further support a dual role for DM during pregnancy and miscarriages. We hypothesize that the baseline DM population in normal pregnancy is in line with an M2 phenotype supporting the ongoing gestation. In contrast, during spontaneous miscarriages, the increased FasL-expressing population could be a part of an M1 phenotype participating in Fas/FasL-related apoptosis. Our results highlight a new aspect of macrophage biology in pregnancy physiology and pathophysiology. Further studies with larger samples are needed to verify the current results and evaluate their clinical impact.     

The three isentropic exponents of wet steam

Real gas isentropic changes may be described using the three well known ideal gas relations,pv ^k =const, p^(1−k)T^k=const andTv ^k-1=const, where exponent k has for each equation a different value k_{p, ν}, k_{p, T} and k_{T, ν} respectively. In this paper the three isentropic exponents theory for real gases is extended to the two phase region. As an application the numerical values of the three exponents are calculated for wet steam.     

Determination of triterpenic acids in natural and alkaline-treated Greek table olives throughout the fermentation process

Maslinic and oleanolic acids are among the most abundant triterpenic acids found in olive fruits. Both acids are considered to be important bioactive compounds which can confer multiple beneficial health effects to the consumer. In the present work, we have monitored and quantified maslinic and oleanolic acids throughout processing in alkaline-treated green olives (Spanish-style) and in natural green olives of the Conservolea variety that is particularly popular in Greece. Our findings clearly demonstrate that the fast de-bittering process with NaOH treatment in Spanish-style olives has a profound negative effect on the concentration of both acids. This decrease of concentration was more prominent regarding maslinic acid when compared to oleanolic acid. In contrast, the slow de-bittering during natural fermentation of green olives had no effect on the content of maslinic or oleanolic acid. To verify the broad applicability of our observation we have also looked into the natural processing of the Kalamon variety (Greek-style). Our findings were consistent, since once again, natural fermentation did not influence the concentration of both acids.     

PU learning-based recognition of structural elements in architectural floor plans

Multimedia Tools and Applications - This work introduces a computational method for the recognition of structural elements in architectural floor plans. The proposed method requires minimal user...     

AN ASSESSMENT OF THE MANAGEMENT OF A RAILWAY ENTERPRISE FROM A MANAGEMENT CYBERNETICS PERSPECTIVE

A project was undertaken in order to identify structural and cultural causes of ineffectiveness in a state-owned railway enterprise. The methodology employed was based on Stafford Beer's Model of the Viable System. An “ethnographic type” preliminary study was undertaken, aiming at highlighting organizational problems from a management cybernetics perspective. Problems in the structuring of operational activities were diagnosed and reported in a previous publication (Paradissopoulos, 1991). This paper examines the structure and the functioning of the headquarters of the Greek Railway. The study demonstrates structural problems associated with a certain organizational culture. Being the outcome of both published material and the author's participation within the enterprise for more than ten years, the study reflects a subjective interpretation of organizational reality. It should therefore be supplemented by a survey within the enterprise, in order to derive the real dimensions of these problems from an analysis of managerial responses.     

Statistical Zero Knowledge and quantum one-way functions

One-way functions are a fundamental notion in cryptography, since they are the necessary condition for the existence of secure encryption schemes. Most examples of such functions, including Factoring, Discrete Logarithm or the RSA function, however, can be inverted with the help of a quantum computer. Hence, it is very important to study the possibility of quantum one-way functions, i.e. functions which are easily computable by a classical algorithm but are hard to invert even by a quantum adversary. In this paper, we provide a set of problems that are good candidates for quantum one-way functions. These problems include Graph Non-Isomorphism, Approximate Closest Lattice Vector and Group Non-Membership. More generally, we show that any hard instance of Circuit Quantum Sampling gives rise to a quantum one-way function. By the work of Aharonov and Ta-Shma [D. Aharonov, A. Ta-Shma, Adiabatic quantum state generation and statistical zero knowledge, in: Proceedings of STOC02 — Symposium on the Theory of Computing, 2001], this implies that any language in Statistical Zero Knowledge which is hard-on-average for quantum computers leads to a quantum one-way function. Moreover, extending the result of Impagliazzo and Luby [R. Impagliazzo, M. Luby, One-way functions are essential for complexity based cryptography, in: Proceedings of FOCS89 — Symposium on Foundations of Computer Science, 1989] to the quantum setting, we prove that quantum distributionally one-way functions are equivalent to quantum one-way functions.     

Modelling the effect of temperature and water activity on the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea

The purpose of the present study was to apply a modelling approach to define the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea on a synthetic medium as a function of temperature and water activity. Both fungal species were grown on malt extract agar at different temperatures (10, 15, 20, 25, 30, 35, 40 and 45 °C) and a_w levels (0.88, 0.90, 0.92, 0.94, 0.96 and 0.99) for a period of 30 days. Growth responses were evaluated over time in terms of colony diameter changes. Growth data were fitted to the primary model of Baranyi and the resulting growth rates were further modeled as a function of temperature and water activity using the cardinal model with inflection (CMI) ( Rosso et al., 1993). A logistic regression quadratic polynomial model was also employed to predict the probability of growth over storage time. Estimated parameters for minimum, maximum and optimum temperatures for growth were 9.1 °C, 46.4 °C and 32.1 °C for B. fulva and 10.5 °C, 43.2 °C and 32.1 °C for B. nivea. The respective values for a_w were 0.893, 0.993 and 0.985 for B. fulva and 0.892, 0.992 and 0.984 for B. nivea. No growth was observed at 0.88 a_w regardless of temperature for both species, whereas B. nivea ascospores could not grow at 10 and 45 °C irrespective of a_w. Regarding growth boundaries, the degree of agreement between predictions and observations was >98% concordant for both species. The erroneously predicted growth cases were 1.4–4.2% false positive and 2.1–3.5% false negative for B. nivea and B. fulva, respectively. The developed logistic model was validated with two literature data sets as well as with data from independent experiments carried out on fruit juices. Validation results showed that agreement with literature data for growth was 25 out of 36 (69.4%) cases, whereas validation on fruit juice data failed in only 6 cases (5 false positives and 1 false negative) out of 128 cases.