Improvement in Organogenesis and the Development of a Transformation Procedure for Cucumber and Muskmelon

A comprehensive study was carried out to optimise and improve a direct shoot organogenesis system to facilitate the transfer of reporter genes (GUSINT and nptII into cucumber (Cucumis sativus L.) and muskmelon (C. melo L.) plants. The studies carried out were: (i) a comparative study on direct and indirect shoot regeneration (ii) the improvement of a direct shoot regeneration system by using an ethylene action inhibitor, silver nitrate and an ethylene biosynthesis inhibitor, cobalt chloride (iii) identification of suitable strains of Agrobacterium tumefaciens and A. rhizogenes that are able to infect cucumber and muskmelon plants (iv) development of an intron containing gene transformation system for both cucurbit species through A. tumefaciens and (v) analysis of transformants. For the comparative study of direct and indirect shoot regeneration, four different types of explants from five elite commercial cucumber cultivars namely Spring Swallow, Suyo Cross, Suyo Long, Tasty Glory. Tasty Green and one muskmelon cultivar called Birdie were used. Explants from both species were cultured onto Murashige and Skoog medium containing different concentrations of 6-benzylaminopurine alone and in combination with either 2,4-dichlorophenoxyacetic acid or naphthalene acetic acid. 6-benzylaminopurine alone at 1.0 or 2.0 mg/L significantly (p<0.05) induced shoot primordia from the largest number of proximal cotyledon and hypocotyl explants of all cucumber cultivars and muskmelon explants tested. However, the addition of either 2,4-dichlorophenoxyacetic acid or naphthalene acetic acid to 6-benzylaminopurine, resulted in a reduction of the shoot primordia induction rate. Higher number of shoots induced from ex plants as well as high numbers of morphological normal shoots were obtained when explants were cultured on. medium containing 6-benzylaminopurine alone. Specific concentrations of indole-butyric acid and naphthalene acetic acid significantly (p<0.05) contributed to root initiation from the largest number of cucumber and muskmelon shoots, respectively. Dark treatment was sufficient to significantly induce root formation from the non-rooting cucumber and muskmelon shoots. The addition of either silver nitrate or cobalt chloride to the seed germination medium or shoot primordia induction medium caused a significant (p<0.05) enhancement of shoot regeneration rate from cucumber cv. SS and TG explants compared to the control. The regeneration rate was further enhanced when these two ethylene inhibitors were added to both SGM and SPI media. Furthermore, the number of shoots induced from explants of both Spring Swallow and Tasty Green cultivars was also enhanced upon the same treatment. However, muskmelon shoot induction and regeneration were reduced when the same treatment was employed

Mechanisms of Corrosion-Induced Cracks in Concrete

Corrosion-induced cracks was simulated in expansion tests.   Kinematical mechanisms of micro-cracks were identified by theSiGMA analysis of acoustic emission (AE).   By applying the boundary element method (BEM), extension of the corrosion-induced crack in an arbitrary direction was analyzed.   It is demonstrated that extension of the corrosion-induced crack is governed by the mode-I failure, although all kinds of micro-cracks are observed  in results of AE analysis

Impacts of Salinity on Soil Properties of Coastal Areas in Bangladesh

Sea level rise is a growing threat for the coastal regions of Bangladesh. It is one of the most densely populated countries of the world where 28% of the population are living in the coastal area. Bangladesh has already been affected by sea level rise through land erosion, salinity intrusion and loss in biodiversity. Saline soil has a detrimental effect upon soil physical and chemical properties. The dominant soil textural classes that occur in the saline areas of these regions are silty clay. In both of the soils pH value of the surface horizon is slightly lower than those of the subsoil and sub stratums. Cation Exchange Capacity (CEC) of all these soils varies from 12.0 to 27.6 meq/100 g soil expressing medium to high status. The organic matter content is medium to high at Asasuni and pretty low at Kalapara. In both areas, nutrient deficiencies of total nitrogen, phosphorous and potassium were quite dominant but sulphur was high. Exchangeable sodium, potassium, calcium and magnesium were in high level. The dominant water soluble cations were Na+, Ca2+, Mg2+ and K+ and anions Cl- and SO4 2-.The amount of accumulated salt was found higher at the surface and decreases with depth

Does Regulatory Change Improve Financial Reporting Timeliness? Evidence from Bangladeshi Listed Companies

The present study is an attempt to empirically test a research question: whether regulatory change can improve financial reporting timeliness in developing countries. Financial reporting delays in Bangladesh have historically been long. In some cases companies are found to publish results of as many as five financial years at a time. Even in 2003, company audits in many cases can be found to take longer than eighteen months. Long audit delay is one of the main causes behind chronic delay observed in issuing financial statements to shareholders. In a significant move to reduce such delays, the country’s Securities and Exchange Commission (SEC), in the year 2000, imposed a mandatory maximum of 120 days to complete audits of listed companies. This provides an interesting setting to examine the research question set out at the beginning. The paper reports the results of multiple linear regressions to test the possible association between financial reporting timeliness and regulatory change while controlling for relevant corporate and auditor attributes. Two levels of analyses were carried out. First, using observations from 1999 and 2001, and then using the observations from 1999 and 2003. The results show that audit delays could be reduced by effective regulatory change. Subsidiaries of MNCs demonstrate significantly shorter delay while companies who do not pay dividends show significantly longer delays. Company size, audit complexity, return on equity, and audit fees (except for one model) do not appear to have any bearing on audit delay

Determinants of IAS Disclosure Compliance in Emerging Economies: Evidence from Exchangelisted Companies in Bangladesh

The study is an attempt to examine empirically the level of disclosure of financial information upon adoption of International Accounting Standards (IASs) in Bangladesh and the association between a number of corporate attributes and levels of disclosure in corporate annual reports in Bangladesh. An unweighted disclosure index comprising 411 items was prepared and applied to 188 corporate annual reports for years ending between January and December 2003. The association between the extent of disclosure and various corporate characteristics was examined using multiple linear regression models. It was found that corporate size, profitability, stock exchange security category (Zcategory or not), size and international link of company's auditor, and multinational subsidiary are all significantly associated with the extent of disclosure. The results were consistent with some previous studies while they contradict with the findings of some other studies

Development and investigation of a cooling system for a parked vehicle using solar energy

The temperature of the interior of a car gets increased substantially during day time when parked under un-shaded parking area for long duration. It is very uncomfortable for the passengers and driver during the start of the driving as the air conditioner will take time to fully cool the interior of the vehicle. This paper mainly focuses on ways to reduce the interior temperature of the parked vehicle. A system has been designed that employs the solar panel, battery, inlet and exhaust fans, temperature sensor and an electric control circuit. The experiment was performed on a car cabin prototype model made using CPU casing of a desktop computer. The inlet air fan is located lower than the exhaust air fan at the car model as the hot air moves up and to have a better air flow distribution. It was observed that the interior temperature of the car model decreased significantly when the system was installed. The simulation was done by using ANSYS FLUENT R15 to investigate the airflow distribution inside the car cabin when inlet and outlet fans were in action. The results showed that the car interior has a better airflow distribution when the inlet fan is positioned lower than the outlet fan

Factors affecting thermosyphon performance- A review of studies

The utilization of the two-phase thermosyphons (TPTs) is expanding for some warmth exchange applications. This paper reviews the performance of thermosyphon TPT systems. The impact of the influencing parameters on the execution of TPTs for example geometry, filling ratio ,working liquid and the inclination angle by different researchers are discussed. The various working limits happening in a thermosyphon that includes dry out, and flooding affects likewise examined. Based on many factors reviewed it shows that the filling ratio exerts small influence in heat transfer and influence is more noticeable for inclination angles. Circulation of working fluid that aided by effects of gravity disable thermosyphon to perform in horizontal position .In addition, it is expected dry out effect could easily occur in the case of high power input, low fill ratio and high inclination angle. This paper could utilize as the beginning point for the researches keen on the TPTs and their renewable energy applications

Empirical model for the electron-impact K-shell-ionization cross sections

The total cross sections of electron-impact single-K-shell ionization of 14 atomic targets ranging from H to U (1 \u3c= Z \u3c= 92) are calculated using a modified version of the BELI formula [Bell , J. Phys. Chem. Ref. Data 12, 891 (1983)] by incorporating both ionic and relativistic corrections in it. The proposed modified Bell model with a single set of parameters is found to provide an excellent description of the experimental data in the reduced energy range 1 \u3c= E/I-K \u3c= 10(6) (E and I-K are, respectively, the incident energy and ionization potential) with a performance level at least as good as any of the existing methods and models