Adaptive Modulation and Coding and Cooperative ARQ in a Cognitive Radio System

In this paper, a joint cross-layer design of adaptive modulation and coding (AMC) and cooperative automatic repeat request (C-ARQ) scheme is proposed for a secondary user in a shared-spectrum environment. First, based on the statistical descriptions of the channel, closed-form expressions of the average spectral efficiency (SE) and the average packet loss rate (PLR) are presented. Then, the cross-layer scheme is designed, with the aim of maximizing the average SE while maintaining the average PLR under a prescribed level. An optimization problem is formed, and a sub-optimal solution is found: the target packet error rates (PER) for the secondary system channels are obtained and the corresponding sub-optimal AMC rate adaptation policy is derived based on the target PERs. Finally, the average SE and the average PLR performance of the proposed scheme are presented

On Amplification by Weak Measurement

We analyze the amplification by the Aharonov-Albert-Vaidman weak quantum measurement on a Sagnac interferometer [P. B. Dixon et al., Phys. Rev. Lett. 102, 173601 (2009)] up to all orders of the coupling strength between the measured system and the measuring device. The amplifier transforms a small tilt of a mirror into a large transverse displacement of the laser beam. The conventional analysis has shown that the measured value is proportional to the weak value, so that the amplification can be made arbitrarily large in the cost of decreasing output laser intensity. It is shown that the measured displacement and the amplification factor are in fact not proportional to the weak value and rather vanish in the limit of infinitesimal output intensity. We derive the optimal overlap of the pre- and post-selected states with which the amplification become maximum. We also show that the nonlinear effects begin to arise in the performed experiments so that any improvements in the experiment, typically with an amplification greater than 100, should require the nonlinear theory in translating the observed value to the original displacement

Volatile Composition and Outgassing in C/2018 Y1 (IWAMOTO): Extending Detection Limits for High-Resolution IR Cometary Spectroscopy at the NASA-IRTF

We used iSHELL, the powerful high-resolution ( /~ 40,000) cross-dispersed IR spectrograph at the NASA-IRTF to measure the native ice composition and outgassing of moderately bright, long-period comet C/2018 Y1 (Iwamoto) (hereafter Y1) within weeks of its discovery. We measured production rates for H2O, and production rates and abundance ratios relative to H2O for eight trace molecules, including the most complete measure of cometary CH4 achieved to date. Compared with mean abundances measured among comets, our study revealed enriched CH3OH and C2H6 yet depleted CO and C2H2, perhaps indicating highly efficient H- atom addition on interstellar grains prior to their incorporation into the nucleus. The combined high spectral resolving power and broad spectral coverage of iSHELL allowed characterizing cometary composition using only three instrument settings, and its long-slit coverage allowed comparing the spatial distributions of molecular emissions and dust continuum

Molecular Modeling Simulation Study of Interactions in Starch/Poly(acrylic acid) Blend

In this work we have studied the nature of interactions between starch and poly(acrylic acid) by using semi-empirical AM1 and PM3 methods. Theoretical computations involved the determination of optimal geometries, binding energies and vibrational frequencies of the blended polymers. Calculations are performed for four pairs of complexes of glucose (Glu) in starch and acrylic acid (mAA) in poly(acrylic acid) PAA. Based on results of calculation, the binding energies show negative values, which indicate that the interactions of glucose and acrylic acid are favorable at the lower energy. This means that the interactions of starch and PAA are stable. Vibrational frequency analysis of hydroxyl OH and carboxyl C=O groups of the 1Glu–1mAA, 1Glu–2mAA and 1Glu–3mAA complexes with single hydrogen bond showed that the stretching of these groups shifts to a lower wave number due to the formation of hydrogen bonds. Keywords:Polymer blends, AM1, PM3

Long-range antiferromagnetic order in the S=1 chain compound LiVGe2O6

The phase transition in the compound LiVGe2O6 has been proposed as a unique example of a spin-Peierls transition in an S=1 antiferromagnetic chain. We report neutron and x-ray diffraction measurements of LiVGe2O6 above and below the phase transition at T=24 K. No evidence is seen for any structural distortion associated with the transition. The neutron results indicate that the low temperature state is antiferromagnetic, driven by ferromagnetic interchain couplings.Comment: 4 pages, 4 ps figures, REVTEX, submitted to PR

Mini-Exon Genotyping of Leishmania Species in Khuzestan Province, Southwest Iran

Background: Leishmaniasis is a protozoan disease cause by Leishmania genus. Anthroponotic and zoonotic cutaneous leishmaniasis are endemic in Iran. The aim of this study was to identify the causative agent of cutaneous leishmaniasis by mini-exon gene in five regions of Khuzestan Province, southwest of Iran. Methods: From 2007 to 2008 in this cross-sectional study, cutaneous samples were collected from patients referred to Health Centers and Hospitals of the Khuzestan Province for cutaneous leishmaniasis diagnosis and cultured in Novy-MacNeal-Nicolle (NNN) and RPMI 1640. The propagated promastigotes were harvested and Leishmania species of cutaneous leishmaniasis were identified by RFLP and DNA sequencing of the PCR generated fragments. Results: L. major and L. tropica were the causative agents of cutaneous leishmaniasis by predominantly of L. major species. The alignment of the mini-exon sequencing isolates with reported sequencing of L. major and L. tropica revealed 92-99 identity. Conclusion: Our study showed that mini-exon PCR-RFLP was useful method to identify the causative species of cutaneous leishmaniasis

Seroprevalence of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular protozoan parasite causing toxoplasmosis in animals and humans. Primary maternal infection with toxoplasmosis during pregnancy is frequently associated with transplacental transmission to the fetus. However it is not certain whether Toxoplasma infection can cause recurrent abortion. The aim of this study was to determine the relationship between Toxoplasma infection and abortion via detection of anti-Toxoplasma gondii antibodies in sera of women with obstetrical problems and compare the results with control group consisting of women with history of normal delivery. Sera from 130 women with abortion and sera of 130 women with normal delivery were tested for IgG and IgM anti-Toxoplasma gondii antibodies by ELISA method. The present study revealed 24.6% of the samples with abortion and 21.5% of the samples with normal delivery were positive for IgG antibodies. However, statistical analysis indicated no significant differences (P>0.05). In addition, IgM antibody was detected in one woman who had aborted but not in women with normal childbirth. This study showed no significant difference between the case and control groups in IgG anti-Toxoplasma antibody but detected one sample with IgM antibodies in woman with abortion during the first trimester of pregnancy. In order to determine the relationship between Toxoplasma infection and abortion, anti-Toxoplasma IgG avidity and PCR to discriminate between recent and prior infections are recommended

Mobility Model for Contact-Aware Data Offloading Through Train-to-Train Communications in Rail Networks

In this paper, we propose a novel mobility model providing train traffic traces essential for train-to-train communication models. As the proposed mobility model works only based on trip timetables and train timetables are currently available in real-time, the produced mobility traces will be also in real-time. Additionally, as no GPS module is used in this method, our proposed model can provide a practical solution when signal from GPS or Assisted GPS is poor or unavailable such as in urban area or inside tunnels. Furthermore, as we used an energy optimization function, the proposed mobility model will provide a guidance trajectory for trains to have an energy-optimized operation. We also develop an algorithm that can determine the specifications of contacts between trains based on the traffic traces obtained from the mobility model. Such specifications includes duration, rate and location of train contacts used for estimation of data exchange capacity between trains through train-to-train communications. We validate our proposed model using data collected from Sydney Trains of Australia. The results obtained from our proposed model show over 98 percent accuracy in comparison with the real data collected via a GPS module from Sydney Trains

Worldwide Analysis of Sedimentary DNA Reveals Major Gaps in Taxonomic Knowledge of Deep-Sea Benthos

International audienceDeep-sea sediments represent the largest but least known ecosystem on earth. With increasing anthropogenic pressure, it is now a matter of urgency to improve our understanding of deep-sea biodiversity. Traditional morpho-taxonomic studies suggest that the ocean floor hosts extraordinarily diverse benthic communities. However, due to both its remoteness and a lack of expert taxonomists, assessing deep-sea diversity is a very challenging task. Environmental DNA (eDNA) metabarcoding offers a powerful tool to complement morpho-taxonomic studies. Here we use eDNA to assess benthic metazoan diversity in 39 deep-sea sediment samples from bathyal and abyssal depths worldwide. The eDNA dataset was dominated by meiobenthic taxa and we identified all animal phyla commonly found in the deep-sea benthos; yet, the diversity within these phyla remains largely unknown. The large numbers of taxonomically unassigned molecular operational taxonomic units (OTUs) were not equally distributed among phyla, with nematodes and platyhelminthes being the most poorly characterized from a taxonomic perspective. While the data obtained here reveal pronounced heterogeneity and vast amounts of unknown biodiversity in the deep sea, they also expose the difficulties in exploiting metabarcoding datasets resulting from the lack of taxonomic knowledge and appropriate reference databases. Overall, our study demonstrates the promising potential of eDNA metabarcoding to accelerate the assessment of deep-sea biodiversity for pure and applied deep-sea environmental research but also emphasizes the necessity to integrate such new approaches with traditional morphology-based examination of deep-sea organisms

Management of tuberculosis of the uterine cervix in the University Hospital Center of Treichville

Genital tuberculosis is a rare entity which is classically presented with nonspecific signs posing diagnostic problems. We report the case of a young patient in genital activity, supported in our hospital for tuberculosis of the uterine cervix. She initially consulted for contact metrorrhagia and speculum examination had found an ulcerative budding cervix making suggest a cervical cancer. Finally, the histology of cervical biopsy confirmed the diagnosis of cervical tuberculosis and the patient was treated with anti-bacillary antibiotics. The evolution was favourable marked by declared healing after 6 months of treatment. The objective of this observation is to discuss the epidemiological, clinical and therapeutic characteristics of this affection