Efficient unified Montgomery inversion with multibit shifting

Computation of multiplicative inverses in finite fields GF(p) and GF(2/sup n/) is the most time-consuming operation in elliptic curve cryptography, especially when affine co-ordinates are used. Since the existing algorithms based on the extended Euclidean algorithm do not permit a fast software implementation, projective co-ordinates, which eliminate almost all of the inversion operations from the curve arithmetic, are preferred. In the paper, the authors demonstrate that affine co-ordinate implementation provides a comparable speed to that of projective co-ordinates with careful hardware realisation of existing algorithms for calculating inverses in both fields without utilising special moduli or irreducible polynomials. They present two inversion algorithms for binary extension and prime fields, which are slightly modified versions of the Montgomery inversion algorithm. The similarity of the two algorithms allows the design of a single unified hardware architecture that performs the computation of inversion in both fields. They also propose a hardware structure where the field elements are represented using a multi-word format. This feature allows a scalable architecture able to operate in a broad range of precision, which has certain advantages in cryptographic applications. In addition, they include statistical comparison of four inversion algorithms in order to help choose the best one amongst them for implementation onto hardware

Purification and characterization of a thermostable glucoamylase produced by Aspergillus flavus HBF34

Glucoamylase (GA) from Aspergillus flavus HBF34 strain was partially purified 120 folds using starch affinity chromatography. Two isoenzymes (GA1 and GA2) were identified by polyacrylamide gel electrophoresis (PAGE) zymography. Sodium dodecyl sulfate (SDS)-PAGE analysis revealed that one of the enzymes consist of one subunit and the other, two subunits. The optimum pH of the purified GA was 6.0 and the optimum temperature was 60°C. GA was found to be stable at temperatures up to 50°C and at a pH range between 3.0 and 9.0. Km and Vmax values of the enzymes were determined using soluble potato starch, glycogen, amylopectin and amylose as substrates and calculated to be 0.046,0.075, 0.1 and 0.125 mg/ml and 769, 1250, 3333 and 2500 U/mg protein, respectively. While GA was activated by Mn2+, Ca2+, Co2+ and Ba2+, it was inhibited by Hg2+, Fe3+, Al3+, Zn2+ and Cu2+. The activity ofGA was found to be tolerant up to 5 M NaCl concentration.  N-bromosuccinimide (NBS) and phenylmethanesulfonylfluoride (PMSF) inhibited the enzyme, suggesting the involvement of tryptophan and serine residues in the catalytic process. Raw corn starch adsorption of GA was found to be 93%. Thin-layer chromatography (TLC) results showed that amylase was in fact a glucoamylase

N-fold Supersymmetry in Quantum Systems with Position-dependent Mass

We formulate the framework of N-fold supersymmetry in one-body quantum mechanical systems with position-dependent mass (PDM). We show that some of the significant properties in the constant-mass case such as the equivalence to weak quasi-solvability also hold in the PDM case. We develop a systematic algorithm for constructing an N-fold supersymmetric PDM system. We apply it to obtain type A N-fold supersymmetry in the case of PDM, which is characterized by the so-called type A monomial space. The complete classification and general form of effective potentials for type A N-fold supersymmetry in the PDM case are given.Comment: 18 pages, no figures; Refs. updated, typos correcte

Fast computation of continued fractions

AbstractWe give an O(log n) algorithm to compute the nth convergent of a periodic continued fraction. The algorithm is based on matrix representation of continued fractions, due to Milne-Thomson. This approach also allows for the computation of first n convergents of a general continued fraction in O(log n) time using O(nlog n) processors

The effects of nitrogen deficiencies on the lipid and protein contents of Spirulina platensis

Nitrogen deficiencies were studied in Spirulina platensis (Cyanophyceae) with the aim of determining the effects of the 50 and 100% deficient nitrogen on the lipid and protein contents of the cell under laboratory conditions. S. platensis cultures were grown in Spirulina medium and kept at the constantroom temperature of 26 ± 2°C, illuminated with fluorescent lamps at an irradiance level of 80 ìmol m-2 s-1 with photoperiod 16:8 (L:D) and aerated continuously. In the Spirulina biomass harvested at the stationary phase, 67.4, 53.5, 5.6% protein and 5.78, 13.66, 17.05% lipid were recorded for the groups of control, 50% N(-) and 100% N(-), respectively. The highest lipid content and 1.00 gL-1 dry-weight were recorded from the culture to which treated 100% N(-).Key words: Spirulina platensis, lipid, nitrogen deficiencies, protein

Position-dependent mass models and their nonlinear characterization

We consider the specific models of Zhu-Kroemer and BenDaniel-Duke in a sech$^{2}$-mass background and point out interesting correspondences with the stationary 1-soliton and 2-soliton solutions of the KdV equation in a supersymmetric framework.Comment: 8 Pages, Latex version, Two new references are added, To appear in J.Phys.A (Fast Track Communication

Measurement, profiles, prevalence, and psychological risk factors of problematic gaming among the Turkish community: a large-scale national study

The present study investigated the prevalence, the potential different profiles, and the associated psychological factors of disordered gaming using data from a large-scale epidemiological study (TURBAHAR [Turkey’s Addiction and Mental Health Risk Profile Map Project]) carried out in Turkey in 2018 with 24,494 participants aged 18–81 years. Participants completed a comprehensive survey comprising a demographic questionnaire, Gaming Addiction Risk Questionnaire, Brief Symptom Inventory, Personal Well-Being Index Adult Form, Positive and Negative Affect Schedule, Toronto Alexithymia Scale, and Experiences in Close Relationships-Revised Scale. Latent class analysis showed the existence of eight different game profiles, which differed in relation to the intensity and specific features of the behavior. Results showed that 1.6% of the participants were problematic gamers. Being male, being younger, lower education level, being single, using alcohol and cigarettes, psychiatric distress, positive and negative affect, and anxious adult attachment were positively associated with problematic gaming

Effects of Apple Vinegar Addition on Aerobic Deterioration of Fermented High Moisture Maize Using Infrared Thermography as an Indicator

This study was carried out to determine the effects of apple vinegar and sodium diacetate addition on the aerobic stability of fermented high moisture maize grain (HMM) silage after opening. In the study, the effect of three different levels (0%, 0.5% and 1%) of apple vinegar (AV) and sodium diacetate (SDA) supplementation to fermented HMM at two different storage conditions (27–29?C, 48% Humidity; 35–37?C, 26% Humidity) were investigated. The material of the study was fermented rolled maize grain with 62% moisture content stored for about 120 days. Silage samples were subjected to aerobic stability test with three replicates for each treatment group. Wendee and microbiological analyses were made at 0, 2, 4, 7, and 12 days. Meanwhile, samples were displayed in the T200 IR brand thermal camera. According to the thermogram results, 1% SDA addition positively affected HMM silages at the second and fourth days of aerobic stability at both storage conditions (p < 0.05). Aerobic stability and infrared thermography analysis indicated that 1% AV, 0.5%, and 1% SDA additions to HMM silages had promising effects. Due to our results, we concluded that thermal camera images might be used as an alternative quality indicator for silages in laboratory conditions. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The authors are grateful to the technical support of the Agricultural Faculty, Tekirdag Namik Kemal University, Turkey