344 research outputs found

    SPECIES AND LIFE-STAGE SPECIFIC DIFFERENCES IN THE SENSITIVITY OF RAINBOW TROUT AND WHITE STURGEON TO CADMIUM AND COPPER: A MECHANISTIC STUDY

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    Marked differences in the sensitivity among fish life-stages and species have been observed for cadmium (Cd) and copper (Cu), two contaminants of particular concern in Canadian surface waters. White sturgeon (Acipenser transmontanus) are highly sensitive to metals such as Cu. Moreover, white sturgeon have also shown significant life-stage-specific differences in sensitivity to metals. When compared to rainbow trout (Oncorhynchus mykiss), white sturgeon are more sensitive to waterborne acute Cu exposure, whereas the trend in sensitivity is reversed with Cd exposure. The mechanisms of life-stage- and species-specific differences in sensitivity among fish species are not well understood, especially for data-poor, non-model species such as white sturgeon. Hence, the overall objective of this study was to characterize the physiological, biochemical and molecular drivers of species-specific differences in the sensitivity of white sturgeon and rainbow trout to Cd and Cu over three different early life-stages. During acute waterborne exposure to Cd and Cu, the most important mechanisms of toxicity are the disruption of calcium (Ca) and sodium (Na) homeostasis, respectively. Therefore, I compared the effect of Cd and Cu on uptake and whole-body levels of Ca and Na, respectively, between rainbow trout and white sturgeon across multiple early life-stages. I showed that the greater sensitivity of white sturgeon to Cu was explained by greater reduction of its sodium Na uptake compared to rainbow trout, when exposed to same waterborne Cu concentration. Similarly, higher sensitivity of rainbow trout to Cd was explained by significantly higher reduction in Ca uptake relative to white sturgeon. With both Cu and Cd, reduction in whole-body ion uptake resulted in reduction of whole-body levels of Na and Ca, respectively, and the response level was significantly higher in the more sensitive species. Additionally, I analysed Cd/Cu accumulation, Cd/Cu induced oxidative stress, metallothionein and heat shock protein responses and compared these parameters between rainbow trout and white sturgeon across multiple early life-stages. Species-specific differences in these parameters were evaluated because they are known to be important pathways through which Cd and Cu cause toxicity. In larval and swim-up life-stages, white sturgeon showed greater Cu-induced oxidative damage (lipid hydroperoxide (LPO) induction) than in rainbow trout, which explained the greater sensitivity of white sturgeon to Cu in early life-stages. Similarly, exposure to Cd showed that rainbow trout, the more sensitive species to Cd, had significantly greater LPO induction at the swim-up and juvenile life-stages as compared to LPO levels in the respective life-stages of white sturgeon. Mechanisms such as antioxidant enzymes, antioxidant molecules, metal accumulation and metallothionein could only partially explain the patterns observed in Cd or Cu induced LPO levels with no consistent response across life-stages. Regardless of the underlying mechanism, LPO seems to be a good indicator of species-specific differences in the sensitivity to Cd and Cu between rainbow trout and white sturgeon in selective life-stages. In conclusion, my study showed that ion physiology parameters such as ion uptake and whole-body ion levels are good indicators of species-specific differences in the sensitivity of rainbow trout and white sturgeon to Cd and Cu, and possibly other metals as well. In addition, LPO levels in the gills also generally explained the species-specific differences in sensitivity to Cd and Cu between rainbow trout and white sturgeon. The parameters identified in this study could be good surrogates for testing species-specific differences in the sensitivity to metals. Moreover, the parameters identified in this study are also good candidates for developing predictive approaches for toxicity testing of metals, after further characterization in more species

    A Security Analysis of IoT Encryption: Side-channel Cube Attack on Simeck32/64

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    Simeck, a lightweight block cipher has been proposed to be one of the encryption that can be employed in the Internet of Things (IoT) applications. Therefore, this paper presents the security of the Simeck32/64 block cipher against side-channel cube attack. We exhibit our attack against Simeck32/64 using the Hamming weight leakage assumption to extract linearly independent equations in key bits. We have been able to find 32 linearly independent equations in 32 key variables by only considering the second bit from the LSB of the Hamming weight leakage of the internal state on the fourth round of the cipher. This enables our attack to improve previous attacks on Simeck32/64 within side-channel attack model with better time and data complexity of 2^35 and 2^11.29 respectively.Comment: 12 pages, 6 figures, 4 tables, International Journal of Computer Networks & Communication

    Development of Friction Flash to Tube (F2T) and application to S355 grade steel

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    Friction Flash to Tube (F2T) is an innovative friction based manufacturing technique to produce seamless tubes based on open die forging, invented at Aalto University. These tubes can be produced economically in small sizes and batches, envisaging applications of high value materials that are not available in the market. The objective of this Master thesis was to develop the experimental condition of F2T as well as the proper parameters in F2T by approaching Taguchi method. The pre-defined parameters to investigate in Taguchi method were established as forging force, tool rotation and initial transient plunging depth and the investigating of geometrical and metallurgical characteristics were done. Cold rolled high strength and low alloy structural steel S355 is the material used in this research work. The parameters of the F2T process were developed based on design of experiments, with geometrical and hardness properties as performance parameters. The optimized conditions and parameters were applied to produce tubes for extensive evalua-tion of the mechanical and metallurgical material properties. The F2T process has specific components and control demands that cannot be met by the existing manufacturing systems. This challenge was overcome by developing one first version of a dedicated system based on an existent Friction Stir Welding equipment. One additional challenge was to produce tubes longer than 40 mm because of buckling. The buckling was prevented by implementing a lateral support system constraining the consumable rod during the initial transient plunging period. The test specimens for extensive mechanical test and metallurgical analysis were extracted from tubes produced with 80 mm in length. These longer tubes were manufactured using the support system to prevent buckling. The results on tensile test, flattening test and flare test of F2T tube reveal that the mechanical properties of produced tubes are as good as tube of similar material produced by another manufacturing technique. The temperature during the application of the F2T process was monitored with thermo-couples. The mechanical properties of produced tubes were evaluated by hardness meas-urement of cross and longitudinal sections. Tensile test were applied to sub-sections of wall of the tubes, and flare and flattening test to the whole tubes. The metallurgical analysis encompasses optical microscopic analysis, and SEM/EBSD with grain size evaluation. The research work demonstrate the feasibility of producing seamless tubes by F2T in structural steel. A correct design of a dedicated system to prevent the buckling, enables to produce long tubes

    Slow breathing has unequal effects on prehypertensives from different ethnic/racial groups: Effect of slow breathing in different ethnic groups

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    In this study, we investigated whether slow breathing reduces blood pressure (BP) in individuals at risk of developing hypertension and if slow breathing has the same effect on Caucasian, African, Arabian and Indian subjects. Also we assessed ethnic/racial differences in low frequency (LF) power and high frequency (HF) power of heart rate variability (HRV). A total of 40 Caucasian men from Ukraine, 39 West African men mostly from Nigeria, 38 Arabic men from Palestine and Israel and 41 South Asian men from India studying at V. N. Karazin Kharkiv National University were recruited in this study. The subjects were further classified into normotensive and prehypertensive groups. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), LF power, HF power of HRV were recorded at spontaneous breathing and at paced breathing of 10 and 6 breaths per minute. It was found that slowing respiratory rate to 6 breaths per minute reduces SBP in prehypertensive Caucasians, Arabs, Indians, but not in Africans. At 6 breaths per minute, natural logarithm of HF (LnHF) power indicating cardiovagal activity was less in normotensive Arabs than in Caucasians, Africans and Indians possibly suggesting an increased risk of developing hypertension; while prehypertensive Africans demonstrated LnHF power higher than Arabs and Indians. When covariates like age and body mass index (BMI) were considered, prehypertensive Africans demonstrated LnHF power higher than in Caucasians also. It is suggested that in prehypertensive Africans the control of autonomic nervous activity is reset to a higher level of parasympathetic outflow

    Sejauh Manakah Kefahaman Guru Mengenai Ciri-ciri Pengurusan Kualiti Menyeluruh (TQM) Dapat Membentuk Amalan Budaya Kerja Kualiti di Kalangan Guru-guru Sekolah Menengah Berasrama Penuh Negeri Kedah

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    Few programmes have been organised by the Ministry of Education Malaysia in the attempt to inculcate the quality culture among the teachers. One of the culture that has been in the practice is Total Quality of Management. The study was designed to assess the perception of teachers on the implementation of TQM elements as the seven qualities of working culture. They are top management commitment, strategic planning, customers satisfaction, rewards and trainings, quality assurance , teamwork and teachers involvement. Demography factors such as gender, academic qualifications, years of service as a teacher, school factor and exposure to TQM courses are used as a measurement to see the respondents perception towards the qualities. The research instrument consists of a total of 54 questions was designed based on "Pekeliling Kemajuan Perkhidmatan Awam, bil. 1/1992", to test the teachers understanding and opinion towards quality management aspects and the implementation of the TQM elements. Statistical analysis of "t-test" and One-way Anova have been used to test the differences while Pearson Correlation 'r' was used to test on the relationship. Findings showed that strategic planning, followed by management responsibility practiced by the school achieved the highest ranking among the seven qualities mentioned. Findings also found that there was no differences in perception based on demography and school factors on the quality of working culture

    Fault Analysis of the KATAN Family of Block Ciphers

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    In this paper, we investigate the security of the KATAN family of block ciphers against differential fault attacks. KATAN consists of three variants with 32, 48 and 64-bit block sizes, called KATAN32,KATAN48 and KATAN64, respectively. All three variants have the same key length of 80 bits. We assume a single-bit fault injection model where the adversary is supposed to be able to corrupt a single random bit of the internal state of the cipher and this fault injection process can be repeated (by resetting the cipher); i.e., the faults are transient rather than permanent. First, we determine suitable rounds for effective fault injections by analyzing distributions of low-degree (mainly, linear and quadratic) polynomial equations obtainable using the cube and extended cube attack techniques. Then, we show how to identify the exact position of faulty bits within the internal state by precomputing difference characteristics for each bit position at a given round and comparing these characteristics with ciphertext differences (XOR of faulty and non-faulty ciphertexts) during the online phase of the attack. The complexity of our attack on KATAN32 is 2^59 computations and about 115 fault injections. For KATAN48 and KATAN64, the attack requires 2^55 computations (for both variants), while the required number of fault injections is 211 and 278, respectively

    Soft Skills Of Engineering Students

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    Soft skills are a combination of personal qualities and interpersonal abilities that enable individuals to work effectively with others, communicate clearly, and collectively solve problems. Soft skills are required for effective problem-solving and decision-making. Soft skills, such as communication, teamwork, and empathy, are essential for developing a collaborative culture that encourages high order thinking and building relationships. By developing these soft skills, engineering students can improve their chances of success both in their academic pursuits and in their future careers. The goal of the study was to evaluate soft skills among engineering students, to provide insight to educators that can help in designing better activities which integrate both skillsets holistically and efficiently. 92 Students were asked to fill out anonymous Likert-like questionnaire about their self-reported soft skills. The findings 1 Corresponding Author S.A. Aziz [email protected] indicate no significant differences between students based on extrinsic factors (gender, campus, department and class), which may lead to both theoretical and educational implications. These findings can be utilized to formulate recommendations for combine soft skills into the engineering curriculum

    Migrating From SQL to NoSQL Database: Practices and Analysis

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    Most of the enterprises that are dealing with big data are moving towards using NoSQL data structures to represent data. Converting existing SQL structures to NoSQL structure is a very important task where we should guarantee both better Performance and accurate data. The main objective of this thesis is to highlight the most suitable NoSQL structure to migrate from relational Database in terms of high performance in reading data. Different combinations of NoSQL structures have been tested and compared with SQL structure to be able to conclude the best design to use.For SQL structure, we used the MySQL data that is stored in five tables with different types of relationships among them. For NoSQL, we implemented three different MongoDB structures. We considered combinations of different levels of embedding documents and reference relationships between documents. Our experiments showed that using a mix of one level embedded document with a reference relationship with another document is the best structure to choose. We have used a database that contains five tables with a variety of relationships many-to-one, and many-to-many. Also the huge amount of data stored in all the structures about 2 millions record/document. The research compares clearly between the performances of retrieving data from different MongDB representation of data and the result shows that in some cases using more than one collection to represent huge data with complex relationships is better than keeping all the data in one document

    Dyeing Chemicals

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    Dyeing auxiliaries play an important role in the determination of the final dyeing quality. The formation of additional complexes with dyes and auxiliary agents enhances the exhaustion of dyes on textile substrates. For aqueous-based dyeing, dye auxiliaries such as chelating agents, dispersing agents, leveling agents, electrolyte, pH control agents, and surfactants form complexes with the dye on natural and synthetic fibers. A growing awareness of the impact of industrial pollution on the environment became crucial for the dyeing industry in the closing decades of the twentieth century. These chapters discuss the characteristics of dyeing chemicals and how auxiliary substances can assist in achieving outstanding dyeing performance
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