Re-visiting the porter hypothesis.

We provide a new formulation of the Porter hypothesis that we feel is in the spirit of the hypothesis. Under this formulation we find that the Porter hypothesis need not hold universally, and identify conditions under which it may or may not hold. We first consider the case where the abatement costs associated with a technology is exogenously given. In that case stricter government regulation increases the incentive for adopting the new technology if the old and the new technologies are relatively environmentally friendly to begin with. We then consider the case where the abatement costs associated with a technology is endogenously given. We show that the Porter hypothesis is likely to hold if the new technology is significantly more ecient in production compared to the old technology, or if both the technologies are relatively ecient in production. Whereas if both the technologies are relatively inecient, then the Porter hypothesis is unlikely to go through. Thus, under the appropriate conditions, the Porter hypothesis may hold even in a static framework.Porter hypothesis ; Environmental policy ; Research and development

Abortive replication of choleraphage Φ 149 in Vibrio cholerae biotype El Tor

Choleraphage Φ 149 adsorbed irreversibly to Vibrio cholerae biotype el tor cells, and 50% of the injected phage DNA bound to the cell membrane. Although no infectious centers were produced at any time during infection, the host macromolecular syntheses were shut off and the host DNA underwent chloramphenicol-inhibitable degradation. Synthesis of monomeric phage DNA continued similar to that observed in the permissive host. However, the concatemeric DNA intermediates produced were unstable and could not be chased to mature phage DNA. Pulse-labeling of UV-irradiated infected cells at different times during infection allowed identification of phage-specific proteins made in this nonpermissive host. Although most of the early proteins were made, only some of the late proteins were transiently synthesized

Stress response in pathogenic bacteria

Bacterial pathogens survive under two entirely different conditions, namely, their natural environment and in their hosts. Response of these pathogens to stresses encountered during transition from the natural environment to human hosts has been described. The virulence determinants of pathogenic bacteria are under the control of transcriptional activators which respond to fluctuations in growth temperature, osmolarity, metal ion concentration and oxygen tension of the environment. The regulation of stress induced genes may occur at the level of transcription or translation or by post-translational modifications. Under certain stress conditions local changes in the superhelicity of DNA induce or repress genes. In addition to their role in survival of bacteria under stressful situations, the stress induced proteins are also implicated in the manifestation of pathogenicity of bacterial pathogensin vivo

Turbine blade failure in a thermal power plant

The failure of a LP (low pressure) turbine blade of a 220 MW thermal power plant is presented. The blade was made of martensitic stainless steel and the structure was tempered martensite. There was no evidence of degradation of blade material. The fracture took place at the aerofoil region, 113-mm from the root. Throughout the blade surface Si rich phases were detected. Several pits/grooves were found on the edges of the blades and chloride was detected in these pits. These were responsible for the crevice type corrosion. The probable carriers of Cl− were Ca and K, which were found on the blade. The failure mode was intergranular type. Possibly the ultimate failure was due to corrosion-fatigue

Evaluating mild traumatic brain injury in adults: an emergency physician’s dilemma

Background: Mild traumatic brain injury (MTBI) is a common presentation in emergency departments across the globe. A controversy about the policy of evaluating them with CT scan and hospital admission or discharge and for these patients. This study is directed towards correlation of clinical profile with CT brain findings of the patients to predict the possibility of an intracranial lesion and need for early neurosurgical intervention.Methods: This prospective observational study was carried out in the Emergency Department (ED) of a tertiary care government medical college and hospital. All patients aged more than 12 years presenting to the ED with mild traumatic brain injury (MTBI) within 24 hours of injury in whom NCCT head (trauma protocol) was done during the Study. Descriptive and analytical statistics were applied. Multiple logistic regression analysis was used to identify factors related to different outcomes.Results: 178 patients with MTBI were enrolled in the study among which intracranial injuries were found by CT scan in 28 patients (15.7%). Odds of finding intracranial injuries were highest with the presence of post-traumatic vomiting, post traumatic amnesia (PTA), pre-existing alcohol use disorder, GCS≤14, focal neurological deficit and clinical signs of basal skull fracture. 2.8% patients required urgent neurosurgical intervention.Conclusions: Presence of post-traumatic vomiting, PTA, alcohol use disorder, GCS≤14, focal neurodeficit and signs of basal skull fracture in a MTBI patient should be considered as high-risk factors for significant intracranial injuries. 

Inadmissible Class of Boolean Functions under Stuck-at Faults

Many underlying structural and functional factors that determine the fault behavior of a combinational network, are not yet fully understood. In this paper, we show that there exists a large class of Boolean functions, called root functions, which can never appear as faulty response in irredundant two-level circuits even when any arbitrary multiple stuck-at faults are injected. Conversely, we show that any other Boolean function can appear as a faulty response from an irredundant realization of some root function under certain stuck-at faults. We characterize this new class of functions and show that for n variables, their number is exactly equal to the number of independent dominating sets (Harary and Livingston, Appl. Math. Lett., 1993) in a Boolean n-cube. We report some bounds and enumerate the total number of root functions up to 6 variables. Finally, we point out several open problems and possible applications of root functions in logic design and testing

Genetic variability, characters association and path analysis for yield and fruit quality components in Brinjal

The experiment was done at AB District Seed Farm, BCKV, Kalyani Simanta, West-Bengal, India during autumn-winter 2013-14 and 2014-15. The characters that exhibited higher Phenotypic and Genotypic Co-efficient of variation values were number of fruits per plant (76.86, 75.63%), fruit weight (43.88, 41.34%), harvest index (23.57, 22.29%), fruit yield per plant (53.61, 51.17%), anthocyanin in peel, total phenols and DPPH (2,2-diphenyl-l-picryl hydrazyl) free radical scavenging (FRS) capacity indicating that a greater amount of genetic variability was present for these characters which provide greater scope for selection. High heritability coupled with high genetic advance as percent of mean was observed for the characters like plant height, days to 1st flowering, days to 50% flowering, number of fruits per plant, fruit weight, harvest index, fruit yield per plant, total sugar, anthocyanin in peel, total phenols and DPPH FRS capacity depicting that these traits were under the strong influence of additive gene action and hence simple selection based on phenotypic performance of these traits would be more effective. Fruit yield per plant showed highly positive significant correlation with number of primary branches per plant, number of fruits per plant, harvest index, vitamin-A and total phenols and significant negative correlation with days to 1st flowering, TSS, total sugars and total protein. Number of fruits per plant imparted the highest positive direct effect on yield followed by harvest index, fruit weight, days to 50% flowering and anthocyanin in peel. Number of fruits per plant and days to flowering were emerged as the main casual factors for positive or negative association of several characters with fruit yield per plant. Therefore, selection for fruit yield per plant based on these characters would be reliable

Influence of Austempering Temperature on Microstructure and Mechanical Properties of Cast Fe-Si-Mn-VSteel

The present investigation was carried out to examine the influence of austempering temperature on the micro-structure and mechanical properties of a low carbon, high silicon (C-0.13%, Si-1.2%, Mn-1%, V-0.08%) cast steels. The Induction melted casting block was homogenized at 1000°C for 6 hrs. The samples for microstructure and the tens-ile specimens were prepared from the cast steel block according to ASTM standards and were imparted three diff-erent austempering heat treatments to produce different microstructure. The samples are austenitisation at 900°C for 30 minute and then rapidly quenched to a salt bath maintained at temperature 350/400/450°C for 10 minute and then finally air cooled. The microstructure were observed under optical and TEM microscopy. show that UTS decreases but % El increases with increasing apstempering tempe-rature. The 400°C austempering temperature exhibited the best combination of UTS and %EI at room temperature (UTS-663 MPa, EL-26%) with revealing microstructure of bainite and retained austenite