833 research outputs found

    Studies of the Synthetic Inorganic Ion Exchanger. V. : The Separation of Zirconium-95 and Niobium-95 by Means of a Stannic Phosphate Cation Exchanger

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    With the aim of developing a method for the separation of ^Zr and ^Nb, various eluants were investigated, a sulfuric acid solution was found to be most suitable for this purpose. After the stannic phosphate exchanger column had been conditioned with 1N nitric acid, the sample solution was passed through it to adsorb ^Zr and ^Nb. By using a 2N sulfuric acid solution and a 3N sulfuric acid -0.01N hydrofluoric acid solution as eluants, ^Zr and ^Nb could be eluted respectively. The separation was not quantitative, however, because of the unfavorable tailing of the elution curves. On the basis of the above results, the possibility of the total radiochemical separation of a long-lived fission product and the mechanism of the adsorption of these ions were discussed

    Cryptanalysis of OCB2

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    We present practical attacks against OCB2, an ISO-standard authenticated encryption (AE) scheme. OCB2 is a highly-efficient blockcipher mode of operation. It has been extensively studied and widely believed to be secure thanks to the provable security proofs. Our attacks allow the adversary to create forgeries with single encryption query of almost-known plaintext. This attack can be further extended to powerful almost-universal and universal forgeries using more queries. The source of our attacks is the way OCB2 implements AE using a tweakable blockcipher, called XEX*. We have verified our attacks using a reference code of OCB2. Our attacks do not break the privacy of OCB2, and are not applicable to the others, including OCB1 and OCB3

    GIFT-COFB is Tightly Birthday Secure with Encryption Queries

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    GIFT-COFB is a finalist of NIST Lightweight cryptography project that aims at standardizing authenticated encryption schemes for constrained devices. It is a block cipher-based scheme and comes with a provable security result. This paper studies the tightness of the provable security bounds of GIFT-COFB, which roughly tells that, if instantiated by a secure nn-bit block cipher, we need 2n/22^{n/2} encrypted blocks or 2n/2/n2^{n/2}/n decryption queries to break the scheme. This paper shows that the former condition is indeed tight, by presenting forgery attacks that work with 2n/22^{n/2} encrypted blocks with single decryption query. This fills the missing spot of previous attacks presented by Khairallah, and confirms the tightness of the security bounds with respect to encryption. We remark that our attacks work independent of the underlying block cipher

    Behavioral analysis of the effects of long-term treatment with L-ornithine in mice

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    L-ornithine has recently received considerable attention as an anxiolytic-like or antifatigue agent in both human and animal studies. However, most previous results were obtained from a single administration of L-ornithine. Accordingly, this study was designed to clarify the effects of long-term L-ornithine treatment on psychological stress and locomotor activity in mice using a variety of behavioral pharmacology methods. In a stress-induced hyperthermia test, 10 days of L-ornithine treatment induced hyperthermia elevation. Pentobarbital-induced sleep time was shortened by the treatment. However, no significant effects were detected in the elevated plus-maze, running wheel, or forced swim tests. These results suggest that long-term treatment with L-ornithine elevates stress sensitivity and arousal level in mice

    Parallelizable Authenticated Encryption with Small State Size

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    Authenticated encryption (AE) is a symmetric-key encryption function that provides confidentiality and authenticity of a message. One of the evaluation criteria for AE is state size, which is memory size needed for encryption. State size is especially important when cryptosystem is implemented in constrained devices, while trivial reduction by using a small primitive is not generally acceptable as it leads to a degraded security. In these days, the state size of AE has been very actively studied and a number of small-state AE schemes have been proposed, but they are inherently serial. It would be a natural question if we come up with a parallelizable AE with a smaller state size than the state-of-the-art. In this paper, we study the seminal OCB mode for parallelizable AE and propose a method to reduce its state size without losing the bit security of it. More precisely, while (the most small-state variant of) OCB has 3n3n-bit state, by carefully treating the checksum that is halved, we can achieve 2.5n2.5n-bit state, while keeping the n/2n/2-bit security as original. We also propose an inverse-free variant of it based on OTR. While the original OTR has 4n4n-bit state, ours has 3.5n3.5n-bit state. To our knowledge these numbers are the smallest ones achieved by the blockcipher modes for parallel AE and inverse-free parallel AE

    On-site analysis for nitrogen oxides using a newly developed portable flow injection analyzer

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    A new portable flow injection system was developed for on-site chemical analysis, which allows the rapid analysis of aqueous samples at sampling sites. The system comprises a newly designed double-plunger micro pump, a six-way sample injector, a reaction coil in a thermostated compartment and a detector. All of these units are connected with 0.5 mmi.d. PTFE tubing. A visible detector is assembled using a maximum wavelength of 525 nm of a light-emitting diode (LED) and 540 nm of an interference filter. The system is of the one-box type, whose dimensions are 160(W) x 160(H) x 320(D) mm, and is easy to carry to the analysis site; the weight is 8 kg. A thermostated compartment is incorporated into the proposed system in order to be used outdoors, where temperatures are changeable. The system can workwith DC 12Vas well as AC 100V; therefore, a car battery or a portable battery can be used as the power source. The analytical data can be memorized in IC cards or a note-book personal computer connected with a RS232C cable. Furthermore, software on the market can be easily used. By using the proposed system, the on-site determination of nitrogen oxides, such as nitrate and nitrite, could be carried out. Calibration graphs for nitrate and nitrite ions were linear over ranges of 0 to 1.0ppm and 0 to 100ppb ofN-NOs and N-NO2 with good precision; the sampling rate was 40~50 samples per hour. The detection limit for N-NO3 and N-NO2 was 0.5 ppb. By using the proposed system, the on-site determination of nitrate and nitrite in river water samples was carried out. The relative standard deviations of ten injections were 0.65% for nitrate and 0.15% for nitrite. Furthermore, nitrate and nitrite in biological samples as a metabolic products of nitric oxide, which have attracted a lot of attension as a messenger of diverse physiological processes, were also determined on-site with high sensitivity. By using a car battery as a power source, the proposed system worked continuously. In addition, it worked for about 5 hours continuously with a portable battery.試料採取現場での迅速な分析,すなわちオンサイト分析のための新しいポータブルフローインジェクション分析計の開発を行った・このFIA装置では,160×160誉320(mm)の箱の中にダブルプランジ ャーマイクロポンプ,試料注入語検出器及び反応恒温槽を組み入れ,重量8kgと小型・軽量化を達成し,持ち運び容易な分析計とした.特に,525nmの発光ダイオード(LED)を光源とする新規検出 器を開発することにより,小型,省電力化が可能となった.温度変化の大きな屋外での測定に耐えられるように,反応恒温槽も装備した.本FIA装置は交流100Vでのほか,直流12Vでも稼働し,カーバ ッテリーや市販のポータブルバッテリーを電源とするオンサイト分析に対応できるよう設計した.カーバッテリーを電源とした場合は長時間の連続運転が可能である.測定データはメモリーカードや RS232Cによりノート型パーソナルコンピュータへの通信も可能で,更に市販の表計算ソフトを利用してデータ処理が可能である.本装置を窒素酸化物のオンサイト分析に応用した.硝酸,亜硝酸イオン標準液による検量線は,0~1・Oppm,0~100ppbの範囲で直線性,再現性共に良好で,1時間当たり40~50試料の分析が可能であった・検出限界(5/Ⅳ=3)は硝酸,亜硝酸態窒素として0.5ppbと通常のFIAシステムを用いる場合と全く変わらない優れた性能を有することが分かった.河川水中の硝酸,亜硝酸イオンのオンサイト分析では10回の繰り返し測定における相対標準偏差は0.65%及び0.15%と良好な結果が得られた.また,血清中の一酸化窒素(NO)の酸化代謝物としての硝酸,亜硝酸イオン濃度のオンサイト分析を行い,良好な結果を得た.本研究で検討したポータブルバッテリーでは1回の充電で5時間の連続運転が可能であった

    Spirulina Effectiveness Study on Child Malnutrition in Zambia

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    Ensuring adequate nutrition among vulnerable children has been a serious challenge in Zambia. Chronic child malnutrition is more predominant at 45 per cent while underweight and wasting are at 15 and 5 per cent respectively. This study tested the effectiveness of spirulina on malnourished children in Zambia. The study took place from June 2012 to February 2013. Sixty children were divided into spirulina treatment and control groups. The outcome of taking spirulina was analysed by collecting anthropometric data. The fixed-effect regression result showed that 10g of spirulina dairy intake leads to improvement by producing 0.29 higher points in the height-for-age z-score (HAZ); confidence interval (CI)[0.0404, 0.535]. On the contrary, the weight-for-age z-score (WAZ) and the mid-upper arm circumference z-score (MUACZ) did not show a significant difference, although treated children showed a larger improvement by 0.09 points and 0.38 points, respectively. This study implied the validity of spirulina in reducing chronic malnutrition

    Stress coping of Asian Muslim Workers : Focusing upon Bangladeshi, Pakistani and Iranian Male Workers

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    The number of foreign workers in Japan has been on increase since latter half of 1980\u27s. However, there has been only few studies, which describes foreign workers from psychological point of view. This study focuses on the stress coping of foreign workers by using semi-structural interview. 64 workers from Bangladesh, Pakistan and Iran participated in the interview. 12 stress areas and 6 different coping strategies were found. Motivation of migration and the length of stay affected their stress coping process. There was tendency that maintaining stable identity became at risk when participants continued to stay in Japan under unstable socioeconomical condition with great cultural differences between Japan and their home countries

    The influence of intention in conflict on the interventions and apologies of children in virtual conflict situations

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    To examine the influence of intention in conflict on the interventions and apologies of children in virtual conflict situations, we conducted experiments with 3- and 5-year-old girls and boys. Our findings suggest that the conflict's intention reflected the interventions, apologies and reasons. An age difference was observed. Five-year-old children gave more effective answers to resolve conflict situations, using both interventions and apologies more than the 3 year-old children. When asked about such interventions and apologies, many 5-year-old children suggested reasons that were focused on the victim's feelings and accepted responsibility for the conflict or expressed a sense of guilt. In contrast, many 3-year-olds decided their behaviors based on roles or evaluations of others. Furthermore, gender differences were observed Most of the girls selected an impartial intervention between victim and attacker; in contrast, many of the boys selected an intervention that supported only the victim. As an attacker, most girls answered apologetically. When questioned about such interventions and apologies, many girls made judgements of right and wrong themselves and accepted responsibility for the conflict or expressed a sense of guilt. In contrast, many of the boys decided their behaviors from the evaluations of others

    Analyzing the Provable Security Bounds of GIFT-COFB and Photon-Beetle

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    We study the provable security claims of two NIST Lightweight Cryptography (LwC) finalists, GIFT-COFB and Photon-Beetle, and present several attacks whose complexities contradict their claimed bounds in their final round specification documents. For GIFT-COFB, we show an attack using qeq_e encryption queries and no decryption query to break privacy (IND-CPA). The success probability is O(qe/2n/2)O(q_e/2^{n/2}) for nn-bit block while the claimed bound contains O(qe2/2n)O(q^2_e/2^{n}). This positively solves an open question posed in~[Khairallah, ePrint~2021/648 (also accepted at FSE~2022)]. For Photon-Beetle, we show an attack using qeq_e encryption queries (using a small number of input blocks) followed by a single decryption query and no primitive query to break authenticity (INT-CTXT). The success probability is O(qe2/2b)O(q^2_e/2^{b}) for a bb-bit block permutation, and it is significantly larger than what the claimed bound tells, which is independent of the number of encryption queries. We also show a simple tag guessing attack that violates the INT-CTXT bound when the rate r=32r=32. Then, we analyze other (improved/modified) bounds of Photon-Beetle shown in the subsequent papers~[Chakraborty et al., ToSC 2020(2) and Chakraborty et al., ePrint~2019/1475]. As a side result of our security analysis of Photon-Beetle, we point out that a simple and efficient forgery attack is possible in the related-key setting. We emphasize that our results do not contradict the claimed ``bit security\u27\u27 in the LwC specification documents for any of the schemes that we studied. That is, we do not negate the claims that GIFT-COFB is (n/2logn)(n/2 - \log n)-bit secure for n=128n=128, and Photon-Beetle is (b/2logb/2)(b/2 - \log b/2)-bit secure for b=256b=256 and r=128r=128, where rr is a rate. We also note that the security against related-key attacks is not included in the security requirements of NIST LwC, and is not claimed by the designers
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