Energy Efficient Scheduling via Partial Shutdown

Motivated by issues of saving energy in data centers we define a collection of new problems referred to as "machine activation" problems. The central framework we introduce considers a collection of $m$ machines (unrelated or related) with each machine $i$ having an {\em activation cost} of $a_i$. There is also a collection of $n$ jobs that need to be performed, and $p_{i,j}$ is the processing time of job $j$ on machine $i$. We assume that there is an activation cost budget of $A$ -- we would like to {\em select} a subset $S$ of the machines to activate with total cost $a(S) \le A$ and {\em find} a schedule for the $n$ jobs on the machines in $S$ minimizing the makespan (or any other metric). For the general unrelated machine activation problem, our main results are that if there is a schedule with makespan $T$ and activation cost $A$ then we can obtain a schedule with makespan \makespanconstant T and activation cost \costconstant A, for any $\epsilon >0$. We also consider assignment costs for jobs as in the generalized assignment problem, and using our framework, provide algorithms that minimize the machine activation and the assignment cost simultaneously. In addition, we present a greedy algorithm which only works for the basic version and yields a makespan of $2T$ and an activation cost $A (1+\ln n)$. For the uniformly related parallel machine scheduling problem, we develop a polynomial time approximation scheme that outputs a schedule with the property that the activation cost of the subset of machines is at most $A$ and the makespan is at most $(1+\epsilon) T$ for any $\epsilon >0$

SS 433: Results of a Recent Multi-wavelength Campaign

We conducted a multi-wavelength campaign in September-October, 2002, to observe SS 433. We used 45 meter sized 30 dishes of Giant Meter Radio Telescope (GMRT) for radio observation, 1.2 meter Physical Research Laboratory Infra-red telescope at Mt Abu for IR, 1 meter Telescope at the State Observatory, Nainital for Optical photometry, 2.3 meter optical telescope at the Vainu Bappu observatory for spectrum and Rossi X-ray Timing Explorer (RXTE) Target of Opportunity (TOO) observation for X-ray observations. We find sharp variations in intensity in time-scales of a few minutes in X-rays, IR and radio wavelengths. Differential photometry at the IR observation clearly indicated significant intrinsic variations in short time scales of minutes throughout the campaign. Combining results of these wavelengths, we find a signature of delay of about two days between IR and Radio. The X-ray spectrum yielded double Fe line profiles which corresponded to red and blue components of the relativistic jet. We also present the broadband spectrum averaged over the campaign duration.Comment: 17 pages 10 figures MNRAS (submitted

GaAs Growth on Sapphire Substrates (C and R Plane) for Integrated Microwave Photonics (IMWP)

The microwave signal processing in the optical domain creates new opportunities for information and communication technology (ICT) and networks by increasing speed, bandwidth, and processing capability. IMWP incorporates the functions of microwave photonics components/subsystems in monolithic or hybrid photonic circuits to meet future needs. Sapphire platforms have the potential to integrate all-in-one, for instance, light source, analog signal processing, light detection, CMOS control circuit, silicon on sapphire to achieve high-performance, low-cost mixed-signal optical links etc. Molecular beam epitaxy (MBE) has been used to grow GaAs on sapphire substrates to integrate optoelectronic devices in the same platform. The initial stage of GaAs thin film growth has been investigated extensively in both c and r plane sapphire substrates. Direct growth of GaAs on both sapphires results in three-dimensional (3D) islands. In c-plane sapphire, 50% twin volume of GaAs islands, and in r-plane sapphire, two primary domains of GaAs islands are observed. A strong interaction between the growth of GaAs on r-plane sapphire is observed than the growth of GaAs on c-plane sapphire. A thin AlAs nucleation layer improves the wetting of both substrates. After inserting the AlAs nucleation layer, in c- plane sapphire, twin volume is reduced to 16%, and in r-plane sapphire twin is introduced. Further, we investigated the effect of growth temperature, pre-growth sapphire substrate surface treatment, and in-situ annealing on the quality of GaAs epilayer on c-plane sapphire substrates. We have been able to reduce the twin volume to below 2% and an XRD rocking curve linewidth to 223 arcsec in a c-plane sapphire substrate. To grow high quality GaAs (111)A buffers on an atomically flat sapphire substrate, a two-step growth method has been introduced where, at an early stage, a GaAs layer has been grown at low temperature, followed by a second high-temperature GaAs growth layer. In addition to the two-step process, an AlAs nucleation layer and multiple annealing steps have been employed. Relaxed, smooth surface morphology and high-quality GaAs is achieved with the presence of the LT GaAs layer. A two-dimensional InGaAs quantum well (QW) was epitaxially grown on the 70 nm GaAs buffer and compared with a reference to two-dimensional InGaAs QW grown on GaAs (111)A substrate. Along with X-ray and high-resolution cross-section transmission electron microscopy, comparable QW photoluminescence intensity and linewidth confirmed our growth strategies effectiveness to produce high-quality GaAs on sapphire. The film thickness was improved up to almost 500 nm by changing the growth parameters such as growth temperature and annealing temperature. We have achieved the room temperature (RT) photoluminescence. The 16 μm microdisk laser was fabricated on GaAs/sapphire system and characterize by micro-PL measurements. The lasing was not successful. The higher surface roughness needs to be optimized to get lasing. We will fabricate GaAs/sapphire QW for electrically pumped laser and realize the photonic chip on the sapphire platform in a long-term goal

Assessment of the Toxic Effect of Hexavalent Chromium on the Hematological Indices in Nile Tilapia, Oreochromis Niloticus

The presence of heavy metals, which are typically released into water bodies as a result of fast industrialization, causes the aquatic environment to become extremely contaminated. Chromium is one of the most common heavy metals in the environment and is used in several types of industries. The effect of sublethal toxicity of hexavalent chromium Cr (VI) on hematological indices of the Nile tilapia, Oreochromis niloticus has been analyzed following exposure of concentration 9.349 mg/L and 18.698 mg/L (10% & 20% of LC50 value) of potassium dichromate (K2Cr2O7) as hexavalent chromium for 7, 15, 30 days. Hematological parameters are the most important indicators of fish health status. The aim of this study was to determine the effect of Cr (VI) toxicity on hematological parameters in O. niloticus. The results show that hemoglobin percentage (Hb%), red blood cell (RBC), mean corpuscular volume (MCV), and platelet count level were significantly (P > 0.05) decreased and the total count of white blood cell (WBC) was significantly (P > 0.05) increased with increasing time of exposure at a concentration of 9.349 mg/L of K2Cr2O7 in the test groups compared to the control group. At the concentration of 18.69 mg/L, Hb%, RBC, MCV, mean corpuscular hemoglobin concentration (MCHC), and platelet count level were significantly (P > 0.05) decreased and the total count of WBC and erythrocyte sedimentation rate (ESR) value were significantly (P > 0.05) increased with the increasing time of exposure in the test groups compared to the control group. To study the R2 value of the linear regression equation, we found that the trend of the chronic toxic effect of hexavalent chromium at 60 and 90 days of both the sublethal concentrations 9.349 mg/L and 18.69 mg/L of K2Cr2O7, where the value of Hb, RBC, packed volume cell (PCV), MCV are found to drastically decreased and the value ESR and WBC are found to drastically increased in the experimental groups compared to the control group. The investigation recommended that the presence of hexavalent chromium in the aquatic medium has a strong impact on the hematological indices in O. niloticus

Unbiased Metagenomic Sequencing for Pediatric Meningitis in Bangladesh Reveals Neuroinvasive Chikungunya Virus Outbreak and Other Unrealized Pathogens.

The burden of meningitis in low-and-middle-income countries remains significant, but the infectious causes remain largely unknown, impeding institution of evidence-based treatment and prevention decisions. We conducted a validation and application study of unbiased metagenomic next-generation sequencing (mNGS) to elucidate etiologies of meningitis in Bangladesh. This RNA mNGS study was performed on cerebrospinal fluid (CSF) specimens from patients admitted in the largest pediatric hospital, a World Health Organization sentinel site, with known neurologic infections (n = 36), with idiopathic meningitis (n = 25), and with no infection (n = 30), and six environmental samples, collected between 2012 and 2018. We used the IDseq bioinformatics pipeline and machine learning to identify potentially pathogenic microbes, which we then confirmed orthogonally and followed up through phone/home visits. In samples with known etiology and without infections, there was 83% concordance between mNGS and conventional testing. In idiopathic cases, mNGS identified a potential bacterial or viral etiology in 40%. There were three instances of neuroinvasive Chikungunya virus (CHIKV), whose genomes were >99% identical to each other and to a Bangladeshi strain only previously recognized to cause febrile illness in 2017. CHIKV-specific qPCR of all remaining stored CSF samples from children who presented with idiopathic meningitis in 2017 (n = 472) revealed 17 additional CHIKV meningitis cases, exposing an unrecognized meningitis outbreak. Orthogonal molecular confirmation, case-based clinical data, and patient follow-up substantiated the findings. Case-control CSF mNGS surveys can complement conventional diagnostic methods to identify etiologies of meningitis, conduct surveillance, and predict outbreaks. The improved patient- and population-level data can inform evidence-based policy decisions.IMPORTANCE Globally, there are an estimated 10.6 million cases of meningitis and 288,000 deaths every year, with the vast majority occurring in low- and middle-income countries. In addition, many survivors suffer from long-term neurological sequelae. Most laboratories assay only for common bacterial etiologies using culture and directed PCR, and the majority of meningitis cases lack microbiological diagnoses, impeding institution of evidence-based treatment and prevention strategies. We report here the results of a validation and application study of using unbiased metagenomic sequencing to determine etiologies of idiopathic (of unknown cause) cases. This included CSF from patients with known neurologic infections, with idiopathic meningitis, and without infection admitted in the largest children's hospital of Bangladesh and environmental samples. Using mNGS and machine learning, we identified and confirmed an etiology (viral or bacterial) in 40% of idiopathic cases. We detected three instances of Chikungunya virus (CHIKV) that were >99% identical to each other and to a strain previously recognized to cause systemic illness only in 2017. CHIKV qPCR of all remaining stored 472 CSF samples from children who presented with idiopathic meningitis in 2017 at the same hospital uncovered an unrecognized CHIKV meningitis outbreak. CSF mNGS can complement conventional diagnostic methods to identify etiologies of meningitis, and the improved patient- and population-level data can inform better policy decisions

Transfer of chromium from environment to fish in East Kolkata wetlands – evaluation by structural equation modeling

Chromium (Cr) is a significant pollutant in the effluents from leather industries and domestic city sewage. Cr was determined in water, sediment, and different tissues (gill, muscle, intestine, liver, and kidney) of Nile tilapia, Oreochromis niloticus harvested from wastewater-fed aquaculture (WFA) situated at Bamonghata, Bantala, Chowbaga and Chingrighata of East Kolkata Wetlands (EKW), a Ramsar site in West Bengal, India. The results showed that Cr concentration in surface water ranged between 0.05 to 0.15 mg/L, while Cr was detected at high concentration (100–300 mg/kg) in the sediment soil of the first three WFAs and in moderate concentration (50–110 mg/kg) in Chingrighata WFA. Average Cr concentrations in the tissues were ranked in the following sequence: kidney&gt;liver&gt;intestine&gt;gill&gt;muscle. However, the extent of accumulation of Cr in different tissues varied between the WFAs. We used Structural Equation Modeling (SEM) to determine the route of Cr transfer. The fitness of the model was evaluated by the performance measures. Cr accumulation pathways varied between the sites depending upon the level of Cr in water or sediment. Except for Bamonghata WFA, sediment was found as the principal source of accumulation of Cr in different tissues of O. niloticus. Cr refluxed from sediment into overlying water and accumulated in fish either through the food chain or through direct accumulation from water. In Bamonghata WFA, the role of sediment in the transfer of Cr could not be established due to the high water depth or biological non-availability of Cr in the sediment. It is concluded from this study that fish reared in the WFAs of EKW are still not hazardous in respect to Cr but require proper management to avoid the influx of Cr-containing effluents into the WFAs. Graphical abstract: [Figure not available: see fulltext.].</p