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Subwavelength optical lattices induced by position-dependent dark states

Subwavelength optical lattices induced by position-dependent dark states

A method for the generation of subwavelength optical lattices based on multilevel dark states is proposed. The dark state is formed by a suitable combination of standing wave light fields, leading to position-dependent populations of the ground states.
Inversion of three-stage stress–strain relation for stainless steel in tension and compression

Inversion of three-stage stress–strain relation for stainless steel in tension and compression

Presented in this paper is a new stress–strain relation for stainless steel alloys that provides the stress as an explicit function of the strain. The relation is an approximate inversion of a recently proposed three-stage stress–strain relation based on a modified Ramberg–Osgood equation. The three-stage relation is a much more accurate formulation than the previous two-stage formulations and is applicable to both tensile as well as compressive stresses.
Prevalence of common phobias and their socio-demographic correlates in children and adolescents in a traditional developing society

Prevalence of common phobias and their socio-demographic correlates in children and adolescents in a traditional developing society

Objective: The aim of this study was to identify the most common phobias in children and adolescents and to determine the prevalence, age distribution, and socio-demographic correlates of phobias. Method: This was a prospective cross-sectional study conducted at public and private schools from July 2009 to February 2009. The questionnaire included socio-demographic information, extra-curricular activities and hobbies, behaviour at home and various phobic fears and it was distributed among children aged 6 to 18 years.
Multiple-module high-gain high-voltage dc-dc transformers for offshore wind energy systems

Multiple-module high-gain high-voltage dc-dc transformers for offshore wind energy systems

Renewable energy sources, such as offshore wind farms, require high voltage gains in order to interface with power transmission networks. These conversions are normally made using bulky, complex, and costly transformers and high-voltage ac-dc converters with unnecessary bidirectional power flow capability.
Neuronal ceroid lipofuscinosis in qatar: report of a novel mutation in ceroid-lipofuscinosis, neuronal 5 in the arab population

Neuronal ceroid lipofuscinosis in qatar: report of a novel mutation in ceroid-lipofuscinosis, neuronal 5 in the arab population

This study sought to genetically define the first family diagnosed with neuronal ceroid lipofuscinosis from Qatar. Onset was in late infancy (3 years), and sequencing in the affected children revealed a novel homozygous c.613C>T change in exon 3 of ceroid-lipofuscinosis, neuronal 5, corresponding to a missense mutation of a conserved amino acid, p.Pro205Ser.
Risk analysis of flare flame-out condition in a gas process facility

Risk analysis of flare flame-out condition in a gas process facility

Flaring is a common method of disposal of flammable waste gases in the downstream industries. Flare flame out (flame lift-off or blow-outs) often occurs causing toxic vapors to discharge. The toxic gases released may have hazardous effects on the surrounding environment.
Tumor associated mesenchymal stem cells protects ovarian cancer cells from hyperthermia through CXCL12

Tumor associated mesenchymal stem cells protects ovarian cancer cells from hyperthermia through CXCL12

Abstract: Hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promise in treatment of ovarian carcinosis. Despite its efficiency for the treatment of peritoneal carcinosis from digestive tract neoplasia, it has failed to demonstrate significant benefit in ovarian cancers. It is therefore essential to understand the mechanism underlying resistance to HIPEC in ovarian cancers.
A thermo-viscoelastic-viscoplastic-viscodamage constitutive model for asphaltic materials

A thermo-viscoelastic-viscoplastic-viscodamage constitutive model for asphaltic materials

A temperature-dependent viscodamage model is proposed and coupled to the temperature-dependent Schapery s nonlinear viscoelasticity and the temperature-dependent Perzyna s viscoplasticity constitutive model presented in Abu Al-Rub et al (2009) and Huang et al (in press) in order to model the nonlinear constitutive behavior of asphalt mixes The thermo-viscodamage model is formulated to be a function of temperature total effective strain and the damage driving force which is expressed in terms of the stress invariants of the effective stress in the undamaged configuration This expression for the damage force allows for the distinction between the influence of compression and extension loading conditions on damage nucleation and growth A systematic procedure for obtaining the thermo-viscodamage model parameters using creep test data at different stress levels and different temperatures is presented The recursive-iterative and radial return algorithms are used for the numerical implementation of the nonlinear viscoelasticity and viscoplasticity models respectively whereas the viscodamage model is implemented using the effective (undamaged) configuration concept Numerical algorithms are imple mented in the well-known finite element code Abaqus via the user material subroutine UMAT The model is then calibrated and verified by comparing the model predictions with experimental data that include creep-recovery creep and uniaxial constant strain rate tests over a range of temperatures stress levels and strain rates It is shown that the presented constitutive model is capable of predicting the nonlinear behavior of asphaltic mixes under different loading conditions (C) 2010 Elsevier Ltd All rights reserved.
Urinary Cell Levels of mRNA for OX40, OX40L, PD-1, PD-L1, or PD-L2 and Acute Rejection of Human Renal Allografts

Urinary Cell Levels of mRNA for OX40, OX40L, PD-1, PD-L1, or PD-L2 and Acute Rejection of Human Renal Allografts

Background. The positive costimulatory proteins OX40 and OX40L and negative regulatory proteins programmed death (PD)-1, PD ligand 1, and PD ligand 2 have emerged as significant regulators of acute rejection in experimental transplantation models. Methods. We obtained 21 urine specimens from 21 renal allograft recipients with graft dysfunction and biopsy-confirmed acute rejection and 25 specimens from 25 recipients with stable graft function and normal biopsy results (stable). 
A robust approach for clock offset estimation in wireless sensor networks

A robust approach for clock offset estimation in wireless sensor networks

The maximum likelihood estimators (MLEs) for the clock phase offset assuming a two-way message exchange mechanism between the nodes of a wireless sensor network were recently derived assuming Gaussian and exponential network delays. However, the MLE performs poorly in the presence of non-Gaussian or nonexponential network delay distributions. Currently, there is a need to develop clock synchronization algorithms that are robust to the distribution of network delays. This paper proposes a clock offset estimator based on the composite particle filter (CPF) to cope with the possible asymmetries and non-Gaussianity of the network delay distributions. Also, a variant of the CPF approach based on the bootstrap sampling (BS) is shown to exhibit good performance in the presence of reduced number of observations. Computer simulations illustrate that the basic CPF and its BS-based variant present superior performance than MLE under general random network delay distributions such as asymmetric Gaussian, exponential, Gamma, Weibull as well as various mixtures
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DeSIGN: Guided Practice for Sign Language

DeSIGN: Guided Practice for Sign Language

Children learn and practice their vocabulary through interaction with parents and friends as well as through formal instruction at school. However, for deaf children, sign language is the main method of communication. Despite the importance of strong vocabulary skills for understanding text, effective verbal communication and integration into society, the average deaf student graduates from American high schools with a fourth grade reading level. This can be partially attributed to the fact that 90% of deaf children are born to hearing parents who are rarely fluent in sign language.
Calcium channels determine how life begins, and ends
Calcium channels determine how life begins, and ends

Calcium channels determine how life begins, and ends

Ongoing work at Weill Cornell Medical College in Qatar (WCMC-Q) is investigating how intracellular calcium (Ca2+) signaling pathways are involved in the very beginning of life as they prepare the egg for fertilization and the initiation of embryogenesis. The National Priorities Research Program-funded work also has wider implications. Since all cells use Ca2+ signals, these studies could impact the treatment of various pathological conditions including infertility, hypertension, and cancer.
Cells in the human body need to be able to sense their environment in order to respond to cues to perform some function. Intercellular signaling, using hormones sent from one part of the body to another, allow, for example, the brain to tell your hand to pick up a pen as neurons in the brain fire action potentials to trigger the relevant muscle actions. For other cells, the message may be to divide or to die if infected by a virus.
Taking gas-to-liquid technology to the next level
Taking gas-to-liquid technology to the next level

Taking gas-to-liquid technology to the next level

In the 1920s, two German scientists—Franz Fischer and Hans Tropsch—developed revolutionary chemical reactions that could transform gas into liquid. These reactions proved particularly valuable to natural gas-based fuel processing. Since the Fischer-Tropsch days, engineers around the world have been working on ways to tweak these gas-to-liquid (GTL) reactions to produce more products, more efficiently and with less environmental impact. An international research team headquartered at Texas A&M University at Qatar (TAMUQ) is making remarkable progress along these lines.

Researchers discover a remarkably easy way to make filters at the nano scale
Researchers discover a remarkably easy way to make filters at the nano scale

Researchers discover a remarkably easy way to make filters at the nano scale

From your average spaghetti strainer to the screen on your windows, filters are a part of our every-day life. In their simplest form, they keep debris out of air and water. Yet as filter technology advances, so does the level of precision around what we can keep out.
Today, it’s possible to create membranes that filter a range of substances on a nano (microscopic) scale, and a QNRF, NPRP grant-funded project has made significant progress in doing just that. A member of the team and advanced research fellow in experimental physics in the Biological and Soft Sciences Department at the University of Cambridge, Dr. Easan Sivaniah, explained:
Researchers build the case for wind and wave studies in Qatar
Researchers build the case for wind and wave studies in Qatar

Researchers build the case for wind and wave studies in Qatar

For the first time, fine detail about the wind and wave conditions around the coast of Qatar has been recorded. By arranging the most sophisticated equipment available on the edge of a 500-meter pier extending into the Gulf, a research team at Texas A&M University at Qatar (TAMUQ) has collected detailed readings of air and wave currents around the peninsula. Their findings highlight a dearth of information on coastal conditions that have the potential to offer vital insights into many sectors.
“The actual research started in trying to understand the relationship between the wind and waves,” said Dr. Reza Sadr, Assistant Professor in the Mechanical Engineering Department at TAMUQ. “Why do we need this? Because there are very poor models to track wind current and predict ocean waves, and this information affects, among other things, marine life, the offshore oil and gas industry and renewable energy initiatives.”
Around the world, the methods for measuring the patterns of wind and waves, also known as the atmospheric surface layer (ASL), are so far based on weather and wind models combined with analysis of the ocean dynamics. Dr. Sadr said that these models, however, need to be fortified with more sophisticated data and analysis for each region in the globe.
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