149 research outputs found
Optimal block cosine transform image coding for noisy channels
The two dimensional block transform coding scheme based on the discrete cosine transform was studied extensively for image coding applications. While this scheme has proven to be efficient in the absence of channel errors, its performance degrades rapidly over noisy channels. A method is presented for the joint source channel coding optimization of a scheme based on the 2-D block cosine transform when the output of the encoder is to be transmitted via a memoryless design of the quantizers used for encoding the transform coefficients. This algorithm produces a set of locally optimum quantizers and the corresponding binary code assignment for the assumed transform coefficient statistics. To determine the optimum bit assignment among the transform coefficients, an algorithm was used based on the steepest descent method, which under certain convexity conditions on the performance of the channel optimized quantizers, yields the optimal bit allocation. Comprehensive simulation results for the performance of this locally optimum system over noisy channels were obtained and appropriate comparisons against a reference system designed for no channel error were rendered
Stabilisation of Deep Soil Cut Using Micropiles and Soil Nailing
The Railway route through south-west part of India (Konkan Railway) is passing through a hilly terrain. The route is developed by cutting the mountains in slopes and construction of tunnels. Many slopes along this route are very deep and steep. The region is characterized by lateritic soil. A heavy monsoon initiates some of the deep slope failures resulting in large magnitude of loss – both in money and life. The initial failure of one of the slope at Chainage 344/900 Km was stabilized by Gabion walls. West side of the Soil cutting was about 100 m long and a lateritic hilly slope steeply rises to 20 m above the track level at the collapse location. Initially the cutting line was 15m away from external track edge. However, after the heavy monsoon in June 2000, the soil slope collapses causing the lateral movement of the gabion wall and lateral shifting of the nearby railway track. The investigation was carried out to study the failure. The scheme of combination of conventional Soil Nails and Micropiles in addition to Gabion wall was proposed. The scheme was executed in Jan 2001 to May 2001. Load Tests were performed on Micropiles and Nails to verify the design. The slope is successfully stable for last 10 years
A user's guide for the signal processing software for image and speech compression developed in the Communications and Signal Processing Laboratory (CSPL), version 1
A complete documentation of the software developed in the Communication and Signal Processing Laboratory (CSPL) during the period of July 1985 to March 1986 is provided. Utility programs and subroutines that were developed for a user-friendly image and speech processing environment are described. Additional programs for data compression of image and speech type signals are included. Also, programs for the zero-memory and block transform quantization in the presence of channel noise are described. Finally, several routines for simulating the perfromance of image compression algorithms are included
The Gut as Reservoir of Antibiotic Resistance: Microbial Diversity of Tetracycline Resistance in Mother and Infant
The microbiota in the human gastrointestinal tract (GIT) is highly exposed to antibiotics, and may be an important reservoir of resistant strains and transferable resistance genes. Maternal GIT strains can be transmitted to the offspring, and resistances could be acquired from birth. This is a case study using a metagenomic approach to determine the diversity of microorganisms conferring tetracycline resistance (Tcr) in the guts of a healthy mother-infant pair one month after childbirth, and to investigate the potential for horizontal transfer and maternal transmission of Tcr genes. Fecal fosmid libraries were functionally screened for Tcr, and further PCR-screened for specific Tcr genes. Tcr fosmid inserts were sequenced at both ends to establish bacterial diversity. Mother and infant libraries contained Tcr, although encoded by different genes and organisms. Tcr organisms in the mother consisted mainly of Firmicutes and Bacteroidetes, and the main gene detected was tet(O), although tet(W) and tet(X) were also found. Identical Tcr gene sequences were present in different bacterial families and even phyla, which may indicate horizontal transfer within the maternal GIT. In the infant library, Tcr was present exclusively in streptococci carrying tet(M), tet(L) and erm(T) within a novel composite transposon, Tn6079. This transposon belongs to a family of broad host range conjugative elements, implying a potential for the joint spread of tetracycline and erythromycin resistance within the infant's gut. In addition, although not found in the infant metagenomic library, tet(O) and tet(W) could be detected in the uncloned DNA purified from the infant fecal sample. This is the first study to reveal the diversity of Tcr bacteria in the human gut, to detect a likely transmission of antibiotic resistance from mother to infant GITs and to indicate the possible occurrence of gene transfers among distantly related bacteria coinhabiting the GIT of the same individual
Responses of Neomegalotomus parvus (Hemiptera: Alydidae) to color and male-lured traps
A Laboratory of Extremophiles: Iceland Coordination Action for Research Activities on Life in Extreme Environments (CAREX) Field Campaign
Existence of life in extreme environments has been known for a long time, and their habitants have been investigated by different scientific disciplines for decades. However, reports of multidisciplinary research are uncommon. In this paper, we report an interdisciplinary three-day field campaign conducted in the framework of the Coordination Action for Research Activities on Life in Extreme Environments (CAREX) FP7EU program, with participation of experts in the fields of life and earth sciences. In situ experiments and sampling were performed in a 20 m long hot springs system of different temperature (57 \ub0C to 100 \ub0C) and pH (2 to 4). Abiotic factors were measured to study their influence on the diversity. The CO2 and H2S concentration varied at different sampling locations in the system, but the SO2 remained the same. Four biofilms, mainly composed by four different algae and phototrophic protists, showed differences in photosynthetic activity. Varying temperature of the sampling location affects chlorophyll fluorescence, not only in the microbial mats, but plants (Juncus), indicating selective adaptation to the environmental conditions. Quantitative polymerase chain reaction (PCR), DNA microarray and denaturing gradient gel electrophoresis (DGGE)-based analysis in laboratory showed the presence of a diverse microbial population. Even a short duration (30 h) deployment of a micro colonizer in this hot spring system led to colonization of microorganisms based on ribosomal intergenic spacer (RISA) analysis. Polyphasic analysis of this hot spring system was possible due to the involvement of multidisciplinary approaches
Cabozantinib Versus Mitoxantrone-prednisone in Symptomatic Metastatic Castration-resistant Prostate Cancer: A Randomized Phase 3 Trial with a Primary Pain Endpoint
Background: Bone metastases in patients with metastatic castration-resistant prostate cancer (mCRPC) are associated with debilitating pain and functional compromise. Objective: To compare pain palliation as the primary endpoint for cabozantinib versus mitoxantrone-prednisone in men with mCRPC and symptomatic bone metastases using patient-reported outcome measures. Design, setting, and participants: A randomized, double-blind phase 3 trial (COMET-2; NCT01522443) in men with mCRPC and narcotic-dependent pain from bone metastases who had progressed after treatment with docetaxel and either abiraterone or enzalutamide. Intervention: Cabozantinib 60 mg once daily orally versus mitoxantrone 12 mg/m2 every 3 wk plus prednisone 5 mg twice daily orally. Outcome measurements and statistical analysis: The primary endpoint was pain response at week 6 confirmed at week 12 (≥30% decrease from baseline in patient-reported average daily worst pain score via the Brief Pain Inventory without increased narcotic use). The planned sample size was 246 to achieve ≥90% power. Results and limitations: Enrollment was terminated early because cabozantinib did not demonstrate any survival benefit in the companion COMET-1 trial. At study closure, 119 participants were randomized (cabozantinib: N =61; mitoxantrone-prednisone: N = 58). Complete pain and narcotic use data were available at baseline, week 6, and week 12 for 73/106 (69%) patients. There was no significant difference in the pain response with cabozantinib versus mitoxantrone-prednisone: the proportions of responders were 15%versus 17%,a −2%difference(95%confidenceinterval:−16%to11%, p = 0.8). Barriers to accrual included pretreatment requirements for a washout period of prior anticancer therapy and a narcotic optimization period to maximize analgesic dosing. Conclusions: Cabozantinib treatment did not demonstrate better pain palliation than mitoxantrone-prednisone in heavily pretreated patients with mCRPC and symptomatic bone metastases. Future pain-palliation trials should incorporate briefer timelines from enrollment to treatment initiation. Patient summary: Cabozantinib was not better than mitoxantrone-prednisone for pain relief in patients with castration-resistant prostate cancer and debilitating pain from bone metastases
Comparative Metagenomics and Population Dynamics of the Gut Microbiota in Mother and Infant
Colonization of the gastrointestinal tract (GIT) of human infants with a suitable
microbial community is essential for numerous aspects of health, but the
progression of events by which this microbiota becomes established is poorly
understood. Here, we investigate two previously unexplored areas of microbiota
development in infants: the deployment of functional capabilities at the
community level and the population genetics of its most abundant genera. To
assess the progression of the infant microbiota toward an adult-like state and
to evaluate the contribution of maternal GIT bacteria to the infant gut, we
compare the infant’s microbiota with that of the mother at 1 and 11
months after delivery. These comparisons reveal that the infant’s
microbiota rapidly acquires and maintains the range of gene functions present in
the mother, without replicating the phylogenetic composition of her microbiota.
Microdiversity analyses for Bacteroides and
Bifidobacterium, two of the main microbiota constituents,
reveal that by 11 months, the phylotypes detected in the infant are distinct
from those in the mother, although the maternal Bacteroides
phylotypes were transiently present at 1 month of age. The configuration of
genetic variants within these genera reveals populations far from equilibrium
and likely to be undergoing rapid growth, consistent with recent population
turnovers. Such compositional turnovers and the associated loss of maternal
phylotypes should limit the potential for long-term coadaptation between
specific bacterial and host genotypes
Detection and Characterization of Wolbachia Infections in Natural Populations of Aphids: Is the Hidden Diversity Fully Unraveled?
Aphids are a serious threat to agriculture, despite being a rather small group of insects. The about 4,000 species worldwide engage in highly interesting and complex relationships with their microbial fauna. One of the key symbionts in arthropods is Wolbachia, an α-Proteobacterium implicated in many important biological processes and believed to be a potential tool for biological control. Aphids were thought not to harbour Wolbachia; however, current data suggest that its presence in aphids has been missed, probably due to the low titre of the infection and/or to the high divergence of the Wolbachia strains of aphids. The goal of the present study is to map the Wolbachia infection status of natural aphids populations, along with the characterization of the detected Wolbachia strains. Out of 425 samples from Spain, Portugal, Greece, Israel and Iran, 37 were found to be infected. Our results, based mainly on 16S rRNA gene sequencing, indicate the presence of two new Wolbachia supergroups prevailing in aphids, along with some strains belonging either to supergroup B or to supergroup A
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