1,501 research outputs found

    Induction of triploidy with caffeine treatment in the African catfish (Clarias gariepinus)

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    Induction of triploidy is one of the biotechnological methods in aquaculture used for genetic manipulation. It refers to a state where organisms have three complete sets of chromosomes instead of two and can result in sterility. Caffeine treatment that is safe and inexpensive, serve to induce triploidy in catfish. To suppress the second meiotic division, fertilized eggs were exposed to three different concentrations (5, 10 and 15 mM) of caffeine solution for 20 min beginning at 3 min after fertilization. After that, the eggs were incubated at ambient temperature until hatching. The induction of triploidy in fry was determined for three concentrations of caffeine by means of flow-cytometric analysis. The lowest rate of triploidy (20.40 ± 1.13%) was obtained in the group treated with 5 mM caffeine and the highest (69.10 ± 2.18%) in the group treated with 15 mM caffeine. Our results suggest that caffeine can be used to induce triploidy in catfish

    Determining the Efficiency of Different Preoperative Difficult Intubation Tests on Patients Undergoing Caesarean Section

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    Background: Pregnancy-induced anatomical and physiological changes in the airway make airway management difficult in obstetric patients; thus, preoperative evaluation of the airway is important for obstetric patients. Aims: To determine the effectiveness of the modified Mallampati test; the interincisor, sternomental and thyromental distances and the upper limb bite test. The second aim was to assess the effectiveness of the combination of the upper limb bite test with the other tests in obstetric patients. Study Design: Cross-sectional study. Methods: Pregnant women (n=250) scheduled for caesarean section were analysed. The patients' ages, heights and weights were collected. Preoperative airway evaluation was done by using a modified version of the Mallampati test. The interincisor, sternomental and thyromental distances were measured, and the upper limb bite test was performed. The laryngoscopy difficulty was evaluated by using Cormack-Lehane classification. Results: No statistically significant differences were found between groups in age, height or weight (p>0.05). The modified Mallampati test and interincisor, sternomental and thyromental distances revealed a lower number of easy intubations than that determined by the Cormack-Lehane classification and a higher number of difficult intubations than the actual number of cases (p<0.05). The sensitivity and specificity of the modified Mallampati test, the upper limb bite test, the interincisor distance test and the sternomental and thyromental distance tests were found to be 73.08, 57.69, 84.62, 80.77 and 88.46 and 90.62, 99.11, 83.04, 84.37 and 87.05, respectively. When the combinations were examined, the sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test were found to be 57.69 and 100, respectively. When the upper limb bite test was combined with the interincisor distance, the sensitivity and specificity were 46.15 and 100, respectively. We found a sensitivity and specificity of 93.75 and 95.30, respectively, for the combination of the upper limb bite test with the thyromental distance test. The sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test and interincisor distance test were found to be 46.15 and 100, respectively. For combination of all the tests, the sensitivity and specificity was 42.31 and 100, respectively. Conclusion: When all combinations are evaluated in the decision of difficult intubation, the combination of the upper limb bite test and thyromental distance test is superior to the use of other methods alone to predict difficult intubation in pregnant women

    Length-weight and length-length relationships of the Mediterranean shad Alosa agone (Scopoli, 1786) from the Northeastern Mediterranean coast of Turkey

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    The relationships between total length (TL), fork length (FL) and standard length (SL), and between TL and weight were investigated for Mediterranenan shad, Alosa agone, from two estuary localities (Karaduvar and Samandag), North-eastern Mediterranean coast of Turkey. A total of 297 specimens, 150 males and 147 females, were captured by gill net and trammel net between September 2006 and May 2007 from the NE Mediterranean Sea coast of Turkey. The values of the exponent b of the length-weight relationships (LWRs) were 3.50 for female and 3.49 for male. The length-length relationship (LLRs) between the three length measurements (TL-FL-SL) were highly correlated (r2>0.99, P<0.001). This study presented the first reference on LWRs and LLRs for Mediterranean shad species from NE Mediterranean coast of Turkey.Key words: Alosa agone, Mediterranean shad, length-weight relationship, length-length relationship, NE Mediterranean Sea

    Financial Performance of Islamic Banks in Turkey and the United Kingdom: A Comparative Study

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    Islamic banks are financial institutions just like conventional banks. However, Islamic banks do not deal with interest and are based on participation. These institutions raise funds and employ them within the scope of Islamic (Shariah) principles where the bank and the depositor share the business, thus sharing the profits and losses. This paper focuses on making a comparative between three Islamic banks in Turkey and five Islamic banks in the United Kingdom in terms of financial performance. More so, it aims to investigate whether or not Islamic banks in Turkey are more profitable, less risky, liquid, operationally efficient, and have a good management quality compared to the Islamic banks in UK. The time span used in this study is one period. The period is four years from 2013 until 2016. Our study used time series data (pooled Least Squares) (PLS) as panel regression on nine financial ratios (CAMEL) to examine the financial performance of these banks according to their profitability, Capital adequacy, Asset quality (riskiness and solvency), Management quality, Earning diversification (operationally efficient), and Liquidity. However, our results are insignificant for UK and significant in Turkey in terms of asset quality and management quality

    Effect of Roughness in the Development of an Adverse Pressure Gradient Turbulent Boundary Layer

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    An experimental study was conducted to examine the effect of surface roughness on the development of an adverse pressure gradient turbulent boundary layer. Hot-wire anemometry measurements were carried out using single and x-wire probes in the APG region of an open return type wind tunnel test section. The same experimental conditions (i.e. T∞, Uref, and Cp) are maintained between the smooth, k+= 0, and rough, k+= 41-60, cases. Results indicate that the mean velocity deficit and Reynolds stress profiles tend to increase with surface roughness. These effects of roughness were successfully removed from the outer mean velocity profiles using the Zagarola and Smits scaling, U∞δ*/δ. Using the integrated boundary layer equation, the skin friction was computed and showed a 58% increase due to the surface roughness effect. The effects of pressure gradient were found to be significant, of which, different profile trends with similar magnitudes were found for outer Reynolds normal stresses scaled with U∞

    Maxing Out: Stocks as Lotteries and the Cross-Section of Expected Returns

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    Motivated by existing evidence of a preference among investors for assets with lottery-like payoffs and that many investors are poorly diversified, we investigate the significance of extreme positive returns in the cross-sectional pricing of stocks. Portfolio-level analyses and firm-level cross-sectional regressions indicate a negative and significant relation between the maximum daily return over the past one month (MAX) and expected stock returns. Average raw and risk-adjusted return differences between stocks in the lowest and highest MAX deciles exceed 1% per month. These results are robust to controls for size, book-to-market, momentum, short-term reversals, liquidity, and skewness. Of particular interest, including MAX reverses the puzzling negative relation between returns and idiosyncratic volatility recently documented in Ang et al. (2006, 2008).

    Numerical Investigation of Shallow Depth Sloshing Absorbers for Structural Control

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    A liquid sloshing absorber consists of a container, partially filled with liquid. The absorber is attached to the structure to be controlled, and relies on the structure’s motion to excite the liquid. Consequently, a sloshing wave is produced at the liquid free surface within the absorber, possessing energy dissipative qualities. The behaviour of liquid sloshing absorbers has been well documented, although their use in structural control applications has attracted considerably less attention. Generally it is accepted that sloshing absorbers with lower liquid levels are more effective energy dissipaters than those with higher levels, although there has not yet been a study to reveal an ‘optimum’ design mechanism. The main limitation of numerically modelling such circumstances is the inherent complexity in the free surface behaviour, predictions of which are limited when using grid-based modelling techniques. Considering such limitations, Smoothed Particle Hydrodynamics (SPH) is used in this study to model a 2-dimensional rectangular liquid sloshing absorber. SPH is a Lagrangian method of solving the equations of fluid flow that is suitable to model liquid sloshing due its grid-free nature, and inherent ability to model complex free surface behaviour. The primary objective of this paper is to numerically demonstrate the effect of tuning a container's width, to complement previous work [6] on the effect of liquid depth. This study is in an attempt to reveal geometry that enables both effective energy transfer to sloshing liquid and to dissipate this energy quickly

    Production of Single Heavy Charged Leptons at a Linear Collider

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    A sequential fourth generation of quarks and leptons is allowed by precision electroweak constraints if the mass splitting between the heavy quarks is between 50 and 80 GeV. Although heavy quarks can be easily detected at the LHC, it is very difficult to detect a sequential heavy charged lepton, L, due to large backgrounds. Should the L mass be above 250 GeV, it can not be pair-produced at a 500 GeV ILC. We calculate the cross section for the one-loop process e+e- -> L tau. Although the cross section is small, it may be detectable. We also consider contributions from the two Higgs doublet model and the Randall-Sundrum model, in which case the cross section can be substantially higher.Comment: 14 pages, 7 figure

    Solid oxide fuel cell hybrid system: A detailed review of an environmentally clean and efficient source of energy

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    This paper reports a review of an environmentally clean and efficient source of energy such as solid oxide fuel cell hybrid systems. Due to climate concerns, most nations are seeking alternative means of generating energy from a clean, efficient and environmental-friendly method. However, this has proven a big hurdle for both academic and industry researchers over many years. Currently, practical and technically feasible solution can be obtained via an integration of a microturbine and a fuel cell (hybrid systems). Combining the two distinct systems in a hybrid arrangement the efficiency of the microturbine increases from 25 to 30% to the 60-65% range. Hence, this paper outlines an engineering power generation solution towards the acute global population growth, the growing need, environmental concerns, intelligent use of energy with attendant environmental and hybrid system layouts concerning arising problems and tentative proposed solutions. Furthermore, advantages of a solid oxide fuel cell hybrid systems with respect to the other technologies are identified and discussed rationally. Special attention is devoted to modelling with software and emulator rigs and system prototypes. The paper also reviews the limitations and the benefits of these hybrid systems in relationship with energy, environment and sustainable development. Few potential applications, as long-term potential actions for sustainable development, and the future of such devices are further discussed

    Prevalence and distribution of the fabella: a radiographic study in Turkish subjects

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    Background: The purpose of this study is to examine the plain knee radiographs in Turkish subjects in order to determine the prevalence of the fabella and analyse the differences between age, gender, laterality and its symmetry pattern. Materials and methods: Bilateral antero-posterior and lateral knee radiographs of 500 patients (250 male and 250 female subjects, 1000 knee radiographs) were randomly selected from the clinical database and retrospectively evaluated. Data on patient age, gender, and knee laterality (right–left) were evaluated from hospital records. The differences between the sesamoid bones at a particular location and the side, sex and age groups were analysed. Results: The overall prevalence of the fabella (unilateral or bilateral) was 22.8% (114 subjects). The fabella was present unilaterally in 38 (7.6%) subjects, while it was present bilaterally in 76 (15.2%) subjects. The prevalence of the fabella was similar between the body sides. The prevalence of the fabella was also similar between genders (unilateral or bilateral cases) and age groups. Conclusions: We examined the prevalence, symmetry pattern, age and gender differences in Turkish population. It is the first study performed on Turkish population with the largest sample in current literature. Prevalence of fabella is found to be 22.8% which is quite similar with other Caucasian ethnic populations
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