Classical and Bayesian estimation of stress-strength reliability of a component having multiple states

PurposeThis article presents the multi-state stress-strength reliability computation of a component having three states namely, working, deteriorating and failed state.Design/methodology/approachThe probabilistic approach is used to obtain the reliability expression by considering the difference between the values of stress and strength of a component, say, for example, the stress (load) and strength of a power generating unit is in terms of megawatt. The range of values taken by the difference variable determines the various states of the component. The method of maximum likelihood and Bayesian estimation is used to obtain the estimators of the parameters and system reliability.FindingsThe maximum likelihood and Bayesian estimates of the reliability approach the actual reliability for increasing sample size.Originality/valueObtained a new expression for the multi-state stress-strength reliability of a component and the findings are positively supported by presenting the general trend of estimated values of reliability approaching the actual value of reliability.</jats:sec

Clinical prognostication of out-of-hospital cardiac arrest: insight from a prospective observational study using the shockable, witnessed, age and pH score

Background: Cardiac arrest remains a leading cause of mortality and morbidity worldwide. Though there are many prognostic tools, the importance of predicting prognosis of out of hospital cardiac arrest in the emergency department (ED) using SWAP (Shockable, witnessed, age and pH) score has not been studied extensively. Methods: We conducted a hospital-based prospective observational study in Kerala, India, focusing on patients who arrived at the ED after experiencing out-of-hospital cardiac arrest (OHCA). For patients who met the inclusion criteria, (all patients who came to ED with OHCA with age more than 18 years) we calculated the SWAP score using historical information and venous blood gas sample analysis. Patients who achieved return of spontaneous circulation (ROSC) were closely monitored, and post-cardiac arrest care was initiated. Patients who achieved sustained ROSC were admitted, and at time of discharge, follow-up was conducted using cerebral performance category (CPC) score. Results: The SWAP score was computed for patients who experienced OHCA. The analysis revealed that patients with favorable outcomes (CPC 1 and 2) had an average SWAP score of 1, while patients with unfavorable outcomes (CPC 3, 4, 5) had an average SWAP score of 1.55. Among the total of 116 patients, 7 individuals (6.03%) survived with positive neurological outcomes (CPC 1 and 2), while 109 patients (93.96%) experienced poor neurological outcomes (CPC 3, 4, 5, and mortality). Conclusions: Patients who had a high SWAP score had a reduced likelihood of survival and sustained ROSC. Conversely, patients with a SWAP score below 2 had a higher probability of experiencing a ROSC and surviving

A Neural Circuit Arbitrates between Persistence and Withdrawal in Hungry Drosophila

In pursuit of food, hungry animals mobilize significant energy resources and overcome exhaustion and fear. How need and motivation control the decision to continue or change behavior is not understood. Using a single fly treadmill, we show that hungry flies persistently track a food odor and increase their effort over repeated trials in the absence of reward suggesting that need dominates negative experience. We further show that odor tracking is regulated by two mushroom body output neurons (MBONs) connecting the MB to the lateral horn. These MBONs, together with dopaminergic neurons and Dop1R2 signaling, control behavioral persistence. Conversely, an octopaminergic neuron, VPM4, which directly innervates one of the MBONs, acts as a brake on odor tracking by connecting feeding and olfaction. Together, our data suggest a function for the MB in internal state-dependent expression of behavior that can be suppressed by external inputs conveying a competing behavioral drive

Molecular and Functional Characterization of the Odorant Receptor2 (OR2) in the Tiger Mosquito Aedes albopictus

In mosquitoes, the olfactory system plays a crucial role in many types of behavior, including nectar feeding, host preference selection and oviposition. Aedes albopictus, known also as the tiger mosquito, is an anthropophilic species, which in the last few years, due to its strong ecological plasticity, has spread throughout the world. Although long considered only a secondary vector of viruses, the potential of its vector capacity may constitute a threat to public health. Based on the idea that an improved understanding of the olfactory system of mosquitoes may assist in the development of control methods that interfere with their behavior, we have undertaken a study aimed at characterizing the A. albopictus Odorant Receptors. Here we report the identification, cloning and functional characterization of the AalOR2 ortholog, that represents the first candidate member of the odorant receptor (OR) family of proteins from A. albopictus. AalOR2 is expressed in the larval heads and antennae of adults. Our data indicate that A. albopictus OR2 (AalOR2) shares a high degree of identity with other mosquito OR2 orthologs characterized to date, confirming that OR2 is one of the most conserved mosquito ORs. Our data indicate that AalOR2 is narrowly tuned to indole, and inhibited by (-)-menthone. In agreement with this results, these two compounds elicit two opposite effects on the olfactory-based behavior of A. albopictus larvae, as determined through a larval behavioral assay. In summary, this work has led to the cloning and de-orphaning of the first Odorant Receptor in the tiger mosquito A. albopictus. In future control strategies this receptor may be used as a potential molecular target

ATOMS : ALMA Three-millimeter Observations of Massive Star-forming regions - XI. From inflow to infall in hub-filament systems

We investigate the presence of hub-filament systems in a large sample of 146 active proto-clusters, using (HCO+)-C-13 J = 1-0 molecular line data obtained from the ATOMS survey. We find that filaments are ubiquitous in proto-clusters, and hub-filament systems are very common from dense core scales (similar to 0.1 pc) to clump/cloud scales (similar to 1-10 pc). The proportion of proto-clusters containing hub-filament systems decreases with increasing dust temperature (T-d) and luminosity-to-mass ratios (L/M) of clumps, indicating that stellar feedback from H ii regions gradually destroys the hub-filament systems as proto-clusters evolve. Clear velocity gradients are seen along the longest filaments with a mean velocity gradient of 8.71 km s(-1) pc(-1) and a median velocity gradient of 5.54 km s(-1) pc(-1). We find that velocity gradients are small for filament lengths larger than similar to 1 pc, probably hinting at the existence of inertial inflows, although we cannot determine whether the latter are driven by large-scale turbulence or large-scale gravitational contraction. In contrast, velocity gradients below similar to 1 pc dramatically increase as filament lengths decrease, indicating that the gravity of the hubs or cores starts to dominate gas infall at small scales. We suggest that self-similar hub-filament systems and filamentary accretion at all scales may play a key role in high-mass star formation.Peer reviewe

Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

Background: DEET, 2-undecanone (2-U), IR3535 and Picaridin are widely used as insect repellents to prevent interactions between humans and many arthropods including mosquitoes. Their molecular action has only recently been studied, yielding seemingly contradictory theories including odorant-dependent inhibitory and odorant-independent excitatory activities on insect olfactory sensory neurons (OSNs) and odorant receptor proteins (ORs). Methodology/Principal Findings: Here we characterize the action of these repellents on two Aedes aegypti ORs, AaOR2 and AaOR8, individually co-expressed with the common co-receptor AaOR7 in Xenopus oocytes; these ORs are respectively activated by the odors indole (AaOR2) and (R)-(2)-1-octen3-ol (AaOR8), odorants used to locate oviposition sites and host animals. In the absence of odorants, DEET activates AaOR2 but not AaOR8, while 2-U activates AaOR8 but not AaOR2; IR3535 and Picaridin do not activate these ORs. In the presence of odors, DEET strongly inhibits AaOR8 but not AaOR2, while 2-U strongly inhibits AaOR2 but not AaOR8; IR3535 and Picaridin strongly inhibit both ORs. Conclusions/Significance: These data demonstrate that repellents can act as olfactory agonists or antagonists, thus modulating OR activity, bringing concordance to conflicting models

Transcriptome profiling of chemosensory appendages in the malaria vector Anopheles gambiae reveals tissue- and sex-specific signatures of odor coding

<p>Abstract</p> <p>Background</p> <p>Chemosensory signal transduction guides the behavior of many insects, including <it>Anopheles gambiae</it>, the major vector for human malaria in sub-Saharan Africa. To better understand the molecular basis of mosquito chemosensation we have used whole transcriptome RNA sequencing (RNA-seq) to compare transcript expression profiles between the two major chemosensory tissues, the antennae and maxillary palps, of adult female and male <it>An. gambiae</it>.</p> <p>Results</p> <p>We compared chemosensory tissue transcriptomes to whole body transcriptomes of each sex to identify chemosensory enhanced genes. In the six data sets analyzed, we detected expression of nearly all known chemosensory genes and found them to be highly enriched in both olfactory tissues of males and females. While the maxillary palps of both sexes demonstrated strict chemosensory gene expression overlap, we observed acute differences in sensory specialization between male and female antennae. The relatively high expression levels of chemosensory genes in the female antennae reveal its role as an organ predominately assigned to chemosensation. Remarkably, the expression of these genes was highly conserved in the male antennae, but at much lower relative levels. Alternatively, consistent with a role in mating, the male antennae displayed significant enhancement of genes involved in audition, while the female enhancement of these genes was observed, but to a lesser degree.</p> <p>Conclusions</p> <p>These findings suggest that the chemoreceptive spectrum, as defined by gene expression profiles, is largely similar in female and male <it>An. gambiae</it>. However, assuming sensory receptor expression levels are correlated with sensitivity in each case, we posit that male and female antennae are perceptive to the same stimuli, but possess inverse receptive prioritizations and sensitivities. Here we have demonstrated the use of RNA-seq to characterize the sensory specializations of an important disease vector and grounded future studies investigating chemosensory processes.</p

Synthesis of Carbon Nanotubes by Single Zone Pyrolysis Technique

Multi-walled carbon nanotube (MWNT) and combination of single-walled (SWNT) and MWNT were synthesized using pyrolysis assisted chemical vapor deposition method. A single hot zone furnace was used for the synthesis of carbon nanotubes at various temperatures in the range of 750-900C. The as-prepared CNT consisted of carbonaceous impurities and traces of transition metal contents. The as-prepared CNT was oxidized at 500C and then treated with hydrochloric acid which resulted in pure CNT with a purity of 95%. The carbon nanotubes were characterized using field emission scanning electron microscopy (FESEM) and micro-Raman spectroscopy techniques. FESEM images clearly showed the presence of carbon nanotubes and the diameters of the MWNT prepared at various temperatures were in the range of 35-100 nm. The Raman spectroscopy data also showed the presence of D, G and 2D peaks which confirm the presence of CNT

Control of infrared emittance of stainless steel using sputtered tungsten thin films for solar thermal power applications

Low infrared (IR) emittance is the key factor of a solar collector. For high temperature solar thermal applications, low emittance is an important parameter, because the thermal radiative losses of the absorbers increase proportionally by T4. Our primary motivation for carrying out this work has been to lower the IR emittance of stainless steel substrate (intrinsic emittance = 0.12-0.13) by coating a thin film of high IR reflecting tungsten (W). Tungsten thin films were deposited on stainless steel substrates using a glow discharge direct current magnetron sputtering system. Emittance as low as 0.03 was obtained by varying the thickness of W coating on stainless steel subsrtae. The influences of structural, morphological and electrical properties of the W coating on its emittance values are studied. The effect of substrate roughness on the emittance of W coating is also examined. Thermal stability of the W coatings is studied in both vacuum and air. Solar selective coatings of AlTiN/AlTiON/AlTiO tandem absorber were deposited on W coated stainless steel substrates, which exhibited absorptance of 0.955 and emittance of 0.08 with a thermal stability of 600°C in vacuum