Metal-Coated <100>-Cut GaAs Coupled to Tapered Parallel-Plate Waveguide for Cherenkov-Phase-Matched Terahertz Detection: Influence of Crystal Thickness

The influence of crystal thickness of metal-coated <100>-cut GaAs (M-G-M) on Cherenkov-phase-matched terahertz (THz) pulse detection was studied. The M-G-M detectors were utilized in conjunction with a metallic tapered parallel-plate waveguide (TPPWG). Polarization-sensitive measurements were carried out to exemplify the efficacy of GaAs in detecting transverse magnetic (TM)- and transverse electric (TE)-polarized THz waves. The reduction of GaAs’ thickness increased the THz amplitude spectra of the detected TM-polarized THz electro-optic (EO) signal due to enhanced electric field associated with a more tightly-focused and well-concentrated THz radiation on the thinner M-G-M. The higher-fluence THz beam coupled to the thinner M-G-M improved the integrated intensity of the detected THz amplitude spectrum. This trend was not observed for TE-polarized THz waves, wherein the integrated intensities were almost comparable. Nevertheless, good agreement of spectral line shapes of the superposed TM- and TE-polarized THz-EO signals with that of elliptically polarized THz-EO signal demonstrates excellent polarization-resolved detection capabilities of M-G-M via Cherenkov-phase-matched EO sampling technique.     

The power law relationship between citation impact and multi-authorship patterns in articles in Information Science &amp; Library Science journals

The aim of this paper is to extend the conversation about the correlation between collaboration and citation impact in articles in Information Science & Library Science journals by analyzing this correlation’s behavior using a power scaling law approach. 28,131 articles that received 215,693 citations were analyzed. The number of these articles that were published through collaboration accounts for 69%. In general, the scaling exponent of multi-authored articles, both international and domestic, increases over time while the exponent of single-authored papers decreases. The citation impact and collaboration patterns exhibit a power law correlation with a scaling exponent of 1.34 ± 0.02. Citations to multi-authored articles increased \(2^{1.34}\) or 2.53 times each time the number of multi-authored papers doubled. The Matthew Effect is stronger for multi-authored papers than for single-authored. The scaling exponent for the power law relationship of domestic multi-authored papers was 1.35 ± 0.02. The citations to domestic multi-authored articles increased \(2^{1.35}\) or 2.55 times each time the number of domestic multi-authored articles doubled. Contrary to previous studies we found that the Matthew Effect is stronger for domestic multi-authored papers than for international multi-authored ones.     

Towards a Sustainable Green Design for Next-Generation Networks

Recently distributed real-time database systems are intended to manage large volumes of dispersed data. To develop distributed real-time data processing, a reality and stay competitive well defined protocols and algorithms must be required to access and manipulate the data. An admission control policy is a major task to access real-time data which has become a challenging task due to random arrival of user requests and transaction timing constraints. This paper proposes an optimal admission control policy based on deep reinforcement algorithm and memetic algorithm which can efficiently handle the load balancing problem without affecting the Quality of Service (QoS) parameters. A Markov decision process (MDP) is formulated for admission control problem, which provides an optimized solution for dynamic resource sharing. The possible solutions for MDP problem are obtained by using reinforcement learning and linear programming with an average reward. The deep reinforcement learning algorithm reformulates the arrived requests from different users and admits only the needed request, which improves the number of sessions of the system. Then we frame the load balancing problem as a dynamic and stochastic assignment problem and obtain optimal control policies using memetic algorithm. Therefore proposed admission control problem is changed to memetic logic in such a way that session corresponds to individual elements of the initial chromosome. The performance of proposed optimal admission control policy is compared with other approaches through simulation and it depicts that the proposed system outperforms the other techniques in terms of throughput, execution time and miss ratio which leads to better QoS.

     

Dietary evaluation of pregnant adolescents during first, second and third trimester

In order to identify risk of inadequate intake of calories and nutrients during pregnancy, 75 pregnant adolescents (14 to 18 years old) apparently healthy, from low socioeconomic level, in their first prenatal control (12 weeks) were studied by two 24 hour recalls and a food frequency questionnaire at each trimester. Nutritional status was assessed by body mass index (pregestation weight/height) and classified according to American Medicine Institute reference. Paired t-test, frequency distribution and ANOVA were used for statistical analysis. Low weight was found in 34.6% of adolescent at the first visit and 5.3% were overweight. Even though, caloric intake was below recommendation, significant increases were observed between first and second trimester for energy, carbohydrates, niacin and zinc (p < 0.001) and for fat, proteins, riboflavin, thiamin, vitamin C, calcium and iron (p < 0.05). From second to third trimester, differences (p < 0.05) were significant only for vitamin A. Between first and third trimester, differences were significant (p < 0.05) for energy, proteins, carbohydrates, niacin, riboflavin, zinc and for thiamin, vitamin A and calcium (p < 0.05). A high proportion of pregnant adolescent did not reach recommendations for energy, folate, calcium and zinc. Food intake pattern did not change significantly among trimesters. Mean total weight gain was 9.2 kg and 0.412 +/- 0.4 g/week. Newborn's mean weight was 3.221 +/- 418 grams. It is concluded that adolescents are at high nutritional risk and deficiency of dietary intake should be followed. Attention should be addressed from the preconceptional period to postpartum in order to improve maternal and fetal conditions.     

Automatic Synthesis of Recursive Programs: The Proof-Planning Paradigm

We describe a proof method that characterises a family of proofs corresponding to the synthesis of recursive functional programs. This method provides a significant degree of automation in the construction of recursive programs from specifications, together with correctness proofs. This method makes use of meta-variables to allow successive refinement of the identity of unknowns, and so allows the program and the proof to be developed hand in hand. We illustrate it with parts of a substantial example—the synthesis of a unification algorithm.     

Antioxidant activity of grapefruit seed extract on vegetable oils

The antioxidant activities of a grapefruit seed extract (GFSE) which contains tocopherols, citric acid and ascorbic acid, were investigated in vegetable oils. Different amounts of GFSE in powder were dissolved in a mixture of soybean oil–sunflower oil. The oxidation was carried out in an AOM equipment at temperatures of 98·7°C, 75°C and 66·5°C. The results indicated prooxidant effects of GFSE at 97·8°C and 75°C possibly due to a blockade effect of a hydroxyl compound by tocopherol. The inhibitor reaction orders at these temperatures were 0·902 and 0·465, respectively, while at 66·5°C the oxidation rate was inverse to GFSE concentration with reaction order of −0·420. These results seem to indicate different reaction mechanisms depending on temperature conditions. The blockade effects were explained on the basis of a proposed complex between tocopherol and citric acid molecules. © 1998 SCI.     

Peimine,an Anti-Inflammatory Compound from Chinese Herbal Extracts,Modulates Muscle-Type Nicotinic Receptors

Fritillaria bulbs are used in Traditional Chinese Medicine to treat several illnesses. Peimine (Pm), an anti-inflammatory compound from Fritillaria, is known to inhibit some voltage-dependent ion channels and muscarinic receptors, but its interaction with ligand-gated ion channels remains unexplored. We have studied if Pm affects nicotinic acetylcholine receptors (nAChRs), since they play broad functional roles, both in the nervous system and non-neuronal tissues. Muscle-type nAChRs were incorporated to Xenopus oocytes and the action of Pm on the membrane currents elicited by ACh (I_AChs) was assessed. Functional studies were combined with virtual docking and molecular dynamics assays. Co-application of ACh and Pm reversibly blocked I_ACh, with an IC₅₀ in the low micromolar range. Pm inhibited nAChR by: (i) open-channel blockade, evidenced by the voltage-dependent inhibition of I_Ach, (ii) enhancement of nAChR desensitization, revealed by both an accelerated I_ACh decay and a decelerated I_ACh deactivation, and (iii) resting-nAChR blockade, deduced from the I_ACh inhibition elicited by Pm when applied before ACh superfusion. In good concordance, virtual docking and molecular dynamics assays demonstrated that Pm binds to different sites at the nAChR, mostly at the transmembrane domain. Thus, Pm from Fritillaria bulbs, considered therapeutic herbs, targets nAChRs with high affinity, which might account for its anti-inflammatory actions.