50 research outputs found
Bayesian compressive sensing framework for spectrum reconstruction in Rayleigh fading channels
Compressive sensing (CS) is a novel digital signal processing technique that has found great interest in
many applications including communication theory and wireless communications. In wireless communications, CS
is particularly suitable for its application in the area of spectrum sensing for cognitive radios, where the complete
spectrum under observation, with many spectral holes, can be modeled as a sparse wide-band signal in the frequency
domain. Considering the initial works performed to exploit the benefits of Bayesian CS in spectrum sensing, the fading
characteristic of wireless communications has not been considered yet to a great extent, although it is an inherent feature
for all sorts of wireless communications and it must be considered for the design of any practically viable wireless system.
In this paper, we extend the Bayesian CS framework for the recovery of a sparse signal, whose nonzero coefficients follow
a Rayleigh distribution. It is then demonstrated via simulations that mean square error significantly improves when
appropriate prior distribution is used for the faded signal coefficients and thus, in turns, the spectrum reconstruction
improves. Different parameters of the system model, e.g., sparsity level and number of measurements, are then varied
to show the consistency of the results for different cases
Anomalous Behaviour and Volatility in Stock Returns are still Live - Efficient Markets Hypothesis? : Perspective from Pakistan Stock Exchange (PSX)
Purpose: This empirical study investigates the anomalous behaviour and volatility in stock return of PSX-100 index of Pakistan Stock Exchange (PSX).
Design/Methodology/Approach: The data is taken from January, 2006 to December, 2018 to detect variability and predictability of stock returns. ARCH and GARCH models are applied to check the volatility in stock returns using dummy variable.
Findings: It is found that there exists positive and significant September effect in Pakistani equity market. The returns are high in the month of September than other months. The constant returns do not exist during the whole year so the efficient market hypothesis contradicts.
Implications/Originality/Value: The Efficient Market Hypothesis is question mark due to volatility for mispricing the securities. The mispricing may have implications for undervalue or overvalue the securities and overall economic activity of equity – stock returns
Management of Chili leaf curl disease (ChiLCD) through resistant germplasm and Nutrients in relation to Environmental Factors
Chili (Capsicum annuum L.) is an important commercial spicy crop grown in many regions across the world. Six chili varieties such as Zinia F1, Desi (Jalalpuri), Desi (Jalalpuri 2), Wonder Hot, Summer Queen F1, and Faisalabad Selection was evaluated against the most devastating and catastrophic Chili’s leaf curl disease caused by Begomovirus Chili leaf curl virus (ChiLCV). Out of all six varieties, Wonder Hot and Summer Queen F1 showed moderately resistant (MR) response whereas three varieties including Zinia F1, Desi (Jalalpuri) and Desi (Jalalpuri 2) had a moderately susceptible (MS) response, and only one variety namely Faisalabad Selection, expressed resistant (R) response. Four varieties; Desi (Jalalpuri), Desi (Jalalpuri 2), Zinia F1, and Wonder Hot, were used for management purposes with four micronutrients in combinations, namely T1 (ZnSO4 + CuSO4), T2 (MnSO4 + CuSO4), T3 (Boric Acid + CuSO4) and T4 (ZnSO4 + CuSO4 + MnSO4 + Boric Acid). When compared to control (58.14%), only T4 demonstrated minimum disease severity (11.63%). In the case of disease incidence, T4 gave the best results with minimum disease incidence (35.65%) as compared to control (92.59%). Treatments were able to decrease the disease progression even in the existing of favorable environmental factors.There was significant (p˂0.05) but positive correlation between wind speed and disease severity. Wind speed was highly correlated with the disease severity of variety Wonder Hot (r=0.91). We concluded that the application of micronutrient activate the plant defense system and at the same time suppress the vector populations
GENETIC ANALYSIS FOR GRAIN YIELD AND VARIOUS MORPHOLOGICAL TRAITS IN MAIZE (ZEA MAYS L.) UNDER NORMAL AND WATER STRESS ENVIRONMENTS
ABSTRACT A genetic analysis study was carried out for various morphological traits in a complete 8 × 8 diallel cross of maize inbred lines under normal irrigation and drought conditions. Estimation of genetic components of variation and graphical presentation deduced that most of the traits like days to pollen shed, anthesis-silking interval, ear height, kernel rows per ear, 100-kernel weight, shelling percentage, grain yield per plant showed over-dominance type of inheritance under both normal and drought conditions unlike leaf rolling which showed partial dominance under normal but over-dominance type of inheritance under drought conditions. It can be inferred that because of over-dominance nature of inheritance of most of the yield related traits, heterosis breeding can be pursued to exploit high yielding hybrids with considerable drought tolerance
Safety and efficacy of ketamine xylazine along with atropine anesthesia in BALB/c mice
Anesthetics are an indispensable prerequisite for surgical intervention and pharmacological animal studies. The objective of present study was to optimize the dose of ketamine (K) and xylazine (X) along with atropine sulfate (A) in order to achieve surgical tolerance in BALB/c mice. Several doses of ketamine (100, 150, 200 mg/kg) and xylazine (10, 15, 20 mg/kg) were mixed and combination of nine doses (K/X: 100/10, 100/15, 100/20, 150/10, 150/15, 150/20, 200/10,200/15,200/20) were evaluated (n=9 per combination). A constant dose of atropine (0.05 mg/kg) was also used to counter side effect. Timerelated parameters were evaluated on the basis of reflexes. KX at dose 200/20 mg/kg produced surgical tolerance in all nine mice with duration 55.00±6.87 minutes. The induction time 0.97±0.09 minutes, sleeping time 90.67±5.81 minutes and immobilization time (102.23±6.83 minutes) were significantly higher than all combination. However, this combination was considered unsafe due to 11 % mortality. While, KX at dose 200/15 mg/kg results in none of the mortality, so was considered as safe. Moreover, this combination produces surgical tolerance in 89 % mice with duration (30.00±7.45 minutes). It was concluded that KX at dose 200/15 mg/kg along with atropine 0.05 mg/kg is safe for performing surgical interventions in BALB/c mice
Effect of slow-release nitrogenous fertilizers on dry matter accumulation, grain nutritional quality, water productivity and wheat yield under an arid environment
Slow release nitrogenous fertilizers can improve crops production and reduce the environmental challenges in agro-ecosystem. There is a need to test the efficiency and performance under arid climatic conditions. The study investigates the effect of slow-release fertilizers (urea, neem coated urea (NCU), sulfur coated urea (SCU) and bioactive sulfur coated urea (BSCU)) on the growth, productivity and grain nutritional qualities of wheat crop. Slow-release fertilizers (SRF) with nitrogen levels (130,117,104 and 94 kg ha−1) were applied with equal splits at sowing, 20 and 60 days after sowing (DAS). Research showed that the BSCU with 130 kg ha−1 increased dry matter accumulation (1989 kg ha−1) after anthesis and grain yield 4463 kg ha−1. The higher plant height (102 cm) was attained by 130 kg N ha−1 SCU while the minimum (77.67 cm) recorded for 94 kg N ha−1 as urea source. Maximum grain NPK concentrations (3.54, 0.66 and 1.07%) were recorded by BSCU 130 kg N ha−1 application. While, the minimum NPK (0.77, 0.19 and 0.35%) were observed by Urea 94 kg N ha−1. The high irrigation water use efficiency (WUE) recorded (20.92 kg ha−1 mm−1) and a crop index of 25.52% by BSCU 130 kg N ha−1 application. Research findings show that generally all SRF but particularly BSCU proved effective and can be recommended for wheat crop under arid environmen
Developing A Synthetic Composite Membrane For Cleft Palate Repair
An oronasal fistula is a passage between the oral and nasal cavity. Currently, surgical procedures use mucosal flaps or collagen grafts to make a barrier between oral and nasal cavities. Our aim was to develop a cell-free synthetic repair material for closure of nasal fistulas. We surface functionalized electrospun polyurethane (PU) and poly-L-lactic acid (PLLA) and composite polymer (PU-PLLA) membranes with acrylic acid through plasma polymerization. Membranes were treated in a layer-by-layer approach to develop highly charged electrostatic layer that could bind heparin as a pro-angiogenic glycosaminoglycan. The properties were evaluated through physical, chemical, and mechanical characterization techniques. Cytotoxicity was tested with MC3T3 pre-osteoblast cell lines for 3, 7, and 14 days, and vasculogenesis was assessed by implantation into the chorio-allantoic membrane in chick embryos for 7 days. In vivo biocompatibility was assessed by subcutaneous implantation in rats for 1, 3, and 6 weeks. The membranes consisted of random fibers of PLLA-PU with fiber diameters of 0.47 and 0.12 μm, respectively. Significantly higher cell proliferation and migration of MC3T3 cells at 3, 7, and 14 days were shown on plasma-coated membranes compared with uncoated membranes. Further, it was found that plasma-coated membranes were more angiogenic than controls. In vivo implantation of membranes in rats did not reveal any gross toxicity to the materials, and wound healing was comparable with the native tissue repair (sham group). We therefore present a plasma-functionalized electrospun composite polymer membrane for use in the treatment of fistulas. These membranes are flexible, non-cytotoxic, and angiogenic, and we hope it should lead to permanent closure of oronasal fistula
Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial
Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma.
Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We
aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding.
Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries.
Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the
minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and
had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were
randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical
apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to
100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a
maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h
for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to
allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients
who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable.
This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124.
Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid
(5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated
treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the
tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18).
Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and
placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein
thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of
5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98).
Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our
results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a
randomised trial
Photosensitization of TiO2 nanofibers by Ag2S with the synergistic effect of excess surface Ti3+ states for enhanced photocatalytic activity under simulated sunlight
TiO2 nanofibers, with mean diameter similar to 200 nm, were fabricated by electrospinning and successfully photosensitized with low bandgap Ag2S nanoparticles of 11, 17, 23 and 40 nm mean sizes, with corresponding loading of 4, 10, 18 and 29 wt.% Ag2S, respectively. 17 nm Ag2S@ TiO2 nanofibers exhibited optimal activity in the photodegradation of methylene blue under simulated sunlight with pseudo-first order rate constant of 0.019 min(-1) compared to 0.009 min(-1) for pure TiO2 nanofibers. In spite of greater visible-light absorption and reduced bandgap, larger than 17 nm Ag2S nanoparticles exhibited sluggish photodegradation kinetics probably due to less photo-induced carriers generation in TiO2 and reduced electron injection rates from the larger sized Ag2S into TiO2. Furthermore, a UVO3 surface treatment induced excess Ti3+ surface states and oxygen vacancies which synergistically enhanced the photodegradation rate constant to 0.030 min(-1) for 17 nm Ag2S@ TiO2 sample which is similar to 70% better than the previously reported for Ag2S/TiO2 hierarchical spheres. This was attributed to the efficient charge separation and transfer driven by increased visible-light absorption, bandgap narrowing and reduced electron-hole recombination rates. The present study demonstrate the potential utilization of Ag2S@ TiO2 nanofibers in filtration membranes for removal of organic pollutants from wastewater