A Collision Avoidance Based Energy Efficient Medium Access Control Protocol for Clustered Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) are typically deployed in energy constrained environments where recharging energy sources and replacing batteries are not viable. This makes energy efficiency in UWSNs a crucial directive to be followed during Medium Access Control (MAC) design. Multiplexing and scheduling based protocols are not ideal for UWSNs because of their strict synchronization requirements, longer latencies and constrained bandwidth.This paper presents the development and simulation analysis of a novel cross-layer communication based MAC protocol called Energy Efficient Collision Avoidance (EECA) MAC protocol. EECA-MAC protocol works on the principle of adaptive power control, controlling the transmission power based on the signal strength at the receiver. EECA-MAC enhances the conventional 4-way handshake to reduce carrier sensing by implementing an enhanced Request to Send (RTS) and Clear to Send (CTS) handshake and an improved back-off algorithm.Simulation analysis shows that the measures taken to achieve energy efficiency have a direct effect on the number of packet retransmissions. Compared to the Medium Access with Collision Avoidance (MACA) protocol, EECA-MAC shows a 40% reduction in the number of packets that are delivered after retransmissions. This reduction, coupled with the reduced signal interference, results in a 16% drop in the energy utilized by the nodes for data transmission

A Quality of Service Aware Source Routing Based Protocol for Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) handle many underwater applications such as environment monitoring, surveillance and navigation. These applications generate varied types of traffic such as continuous bit rate, sporadic and different packet sizes, leading to additional QoS requirements that are traffic and application dependent. This paper presents the development of a Quality of Service Aware Source Routing (QASR) protocol. QASR discovers multiple paths from the sources to the sinks and selects the most QoS compatible route among them. QASR is distinctive because it incorporates multiple QoS parameters such as Signal to Noise Ratio (SNR), latency and residual energy. Depending on which of these parameters are chosen, QASR has three variants, namely, QASR-Latency (QASR-L), QASR-Residual Energy (QASR-RE) and QASR-Signal to Noise Ratio (QASR-SNR). The performance of QASR protocol is compared against traditional source routing protocols, with simulations showing a reduction of about 10% to 20% in latency and about 5% to 10% lesser energy consumption than source routing. QASR protocol exhibits comparable performance to classic source routing protocols while simultaneously adhering to the QoS requirements of the application. It is also worth noting that the performance profile of all the three variants of QASR do not have sudden and drastic variations, with the performance profiles showing consistent trend-lines

Cosmetovigilance: knowledge, attitude and practice study

Background: Adverse reactions due to cosmetics should be reported to avoid similar incidences and is highly required to evaluate the risks and benefits of ingredients used in cosmetics. Methods: This study is to evaluate the knowledge, attitude, and practice of cosmetovigilance among PGs, interns, and consumers of cosmetics. This was a cross-sectional questionnaire- based study conducted among 180 participants of SSMC Tumkur, Karnataka, in India for a period of 1 month. Results: The Results obtained were analysed using descriptive statistics.: About 46.1% of the participants were aware about the concept of cosmetovigilance. Only an average of about 5% of participants practiced this concept but the attitude towards this concept was satisfactory. Conclusions: Overall the participants had a less satisfactory overview of this concept and hence educational interventions can aid in serving the purpose especially among medical students

Study of Vibration Behaviour of Stiffened Polymer Composite Shells for Underwater Structural Applications

This paper presents vibration behavior of ring stiffened polymer composite thick shells used for underwater structures. Filament wound shells stiffened with internal and external rings and with hemispherical ends were tested for vibration in air and water in free-free boundary condition using roving hammer and fixed response method. Modal testing of the shells was performed under hydrostatic loading in a custom designed buckling tester for determining natural frequency at higher sea depths. Accelerometer was mounted on the inner surface of the shell. It was excited using a plumbob, rope and pulley arrangement. Experimental results were validated by modal analysis using Hyperworks and ANSYS. Vibration behavior in water was simulated by Fluid structure interaction approach. Experimental first natural frequency in water was lesser than that in air. With increase in hydrostatic pressure, the shell showed moderate variation in natural frequency. The experimental and numerical results of natural frequency and mode shapes were in good agreement with each other. Natural frequencies were lower in long and thick shells

Cadmium in the purpleback flying squid Sthenoteuthis oualaniensis (Lesson, 1830) along northwest coast of India

The purpleback flying squid Sthenoteuthis oualaniensis (Lesson, 1830) is landed in small quantities along the northwest coast of India. Keeping in view the possibility of utilization of this species for domestic and export markets, the cadmium accumulation in the body tissues, which often causes concern, was studied. The dorsal mantle length of male and female observed during the study ranged from 34 to 47 cm and 30 to 32 cm respectively. The highest mean concentration of 435.22 ± 61.27 μg g-1 (mean ± S.E.) of Cd was found in the liver. Accumulation of Cd was also prominent in the gut, gills and skin. Moderate concentration of Cd (1 to 4 μg g-1) was observed in the nidamental gland, accessory nidamental gland, eyes, tentacles and muscle. In the gonads and arms, the concentration was below the acceptability level of 1.0 μg g-1. Higher accumulation in most of the organs/tissues of larger squids was observed. Significantly higher accumulation (p < 0.05) was noticed in the liver of larger specimens, indicating bioaccumulation. As the mean Cd content in the edible part was more than 1.0 μg g-1, this study highlights the need for detailed investigations to understand the bioaccumulation of Cd in Sthenoteuthis oualaniensi

Fusarium oxysporum f. sp. lycopersici causal agent of vascular wilt disease of tomato: Biology to diversity– A review

Tomato (Lycopersicon esculentum) is one of the widely grown vegetables worldwide. Fusarium oxysporum f. sp. lycopersici (FOL) is the significant contributory pathogen of tomato vascular wilt. The initial symptoms of the disease appear in the lower leaves gradually, trail by wilting of the plants. It has been reported that FOL penetrates the tomato plant, colonizing and leaving the vascular tissue dark brown, and this discoloration extends to the apex, leading to the plants wilting, collapsing and dying. Therefore, it has been widely accepted that wilting caused by this fungus is the result of a combination of various physiological activities, including the accumulation of fungal mycelia in and around xylem, mycotoxin production, inactivation of host defense, and the production of tyloses; however, wilting symptoms are variable. Therefore, the selection of molecular markers may be a more effective means of screening tomato races. Several studies on the detection of FOL have been carried out and have suggested the potency of the technique for diagnosing FOL. This review focuses on biology and variability of FOL, understanding and presenting a holistic picture of the vascular wilt disease of tomato in relation to disease model, biology, virulence. We conclude that genomic and proteomic approachesare greater tools for identification of informative candidates involved in pathogenicity, which can be considered as one of the approaches in managing the disease

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multi-centre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%)

Biochemical defence responses of resistant and susceptible rice genotypes against blast pathogen magnaporthe oryzae

Rice blast is the leading fungal disease which is caused by Magnaporthe oryzae that contributes for the significant decline in the rice yield throughout the globe. There is a need for the understanding of biochemical changes in rice plant during blast infection for the development of novel disease control strategies. In the present study, we isolated M. oryzae from the local paddy fields and the fungal isolates (VCF and PON) were identified by ITS-PCR using genomic DNA samples. Further, we inoculated resistant (BR2655 and TUNGA) and susceptible (INTAN and HR12) rice cultivars with PON and VCF isolates. PON isolate showed relatively high virulence compared to VCF and standard MTCC fungal strains. Therefore, we evaluated the effect of PON on the total protein content and plant defence-related key enzymes (peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, β-glucosidase, chitinase and lipoxygenase) activities between 24- and 120-hour post-inoculation (hpi). The results demonstrated the decrease in total protein content in all the inoculated cultivars. In addition, we observed the variation in the activity of peroxidase, polyphenol oxidase, β-glucosidase, chitinase and lipoxygenase at different time points in all the tested rice plants compared to respective controls. However, no significant difference was observed in the phenylalanine ammonia lyase activity relative to its control. Taken together, this study emphasizes on the variation in the activities of plant defence enzymes in different plant cultivars against the tested fungal pathogen and also implementation of defence enzymes as biochemical markers for resistant breeding

Peptide conformations. Crystal structures of tert-butyloxycarbonylglycyl-L<SUB>-</SUB>proline and its benzyl ester

The crystal structures of tert-butyloxycarbonylglycyl-L-proline and its benzyl ester are respond. Both molecules show similar, extended conformation and there is no hint of the folded conformation that had earlier been suggested for tert-butyloxycarbonylglycyl-L-proline. It us shows that differences in the IR spectra of the two crystals, which had been interpreted in terms of an intramolecular hydrogen bond in the orthombic space group P2<SUB>1</SUB>2<SUB>1</SUB>2<SUB>1</SUB>, with cill dimensions a=5.743 (2), b=23.849 (5), and c=10.440 (2) Å for the free peptide and a=15.381 (3), b=19.112 (4), c=6.638 (2) Å for the benzyl ester. Least-squares refinement led to R indxes of 0.049 and 0.037 for 1344 and 2273 reflections with positive net intensity