10,711 research outputs found
Scattering of positrons and electrons by alkali atoms
Absolute total scattering cross sections (Q sub T's) were measured for positrons and electrons colliding with sodium, potassium, and rubidium in the 1 to 102 eV range, using the same apparatus and experimental approach (a beam transmission technique) for both projectiles. The present results for positron-sodium and -rubidium collisions represent the first Q sub T measurements reported for these collision systems. Features which distinguish the present comparisons between positron- and electron-alkali atom Q sub T's from those for other atoms and molecules (room-temperature gases) which have been used as targets for positrons and electrons are the proximity of the corresponding positron- and electron-alkali atom Q sub T's over the entire energy range of overlap, with an indication of a merging or near-merging of the corresponding positron and electron Q sub T's near (and above) the relatively low energy of about 40 eV, and a general tendency for the positron-alkali atom Q sub T's to be higher than the corresponding electron values as the projectile energy is decreased below about 40 eV
Understanding the burden of idiopathic generalized epilepsy in the United States, Europe, and Brazil: An analysis from the National Health and Wellness Survey.
The aim of this study was to understand the current burden of primary generalized tonic-clonic seizures (PGTCS) associated with idiopathic generalized epilepsy (IGE) as a function of seizure frequency. We analyzed data for (IGE) as a proxy measure of PGTCS. Little is known about the quality of life (QoL), health utility, productivity, healthcare resource utilization (HRU), and cost burden of PGTCS or IGE. Patients were identified from the US (2011, 2012, & 2013), 5EU (2011 & 2013), and Brazil (2011 & 2012) National Health and Wellness Survey, a nationally representative, internet-based survey of adults (18+ years). Patients that self-reported a diagnosis of IGE were categorized into seizure frequencies of: ≥1 seizure per week, 1-3 seizures per month, 1-4 seizures per year, or <1 seizure per year. QoL was measured using the SF-36v2 Mental (MCS) and Physical Component Summary (PCS) scores, health utilities with the SF-6D, productivity with the Work Productivity and Activity Impairment (WPAI) questionnaire, and HRU as reported in the past six months. Unit costs were estimated from the literature and multiplied against HRU values to calculate direct costs and WPAI values to calculate indirect costs. Generalized linear regression was utilized to examine the relationship between seizure frequency and each measure of burden with adjustment for covariates. Out of the general population surveyed, IGE was self-reported in 782 of 176,093 (US), 172 of 30,000 (UK), 106 of 30,001 (Germany), 87 of 30,000 (France), 31 of 12,011 (Spain), 22 of 17,500 (Italy), and 34 of 24,000 (Brazil). Persistent seizures (≥1 per year) were reported in over 40% of patients with IGE (10-15% with ≥1 seizure per week, 10-15% with 1-3 seizures per month, 20-25% with 1-4 seizures per year). Over 75% were treated with antiepileptic drugs (AEDs). Compared with those having <1 seizure per year (reference group), patients in the two most frequent seizure categories reported worse MCS and PCS scores. Patients in the three highest seizure frequency groups consistently reported worse health utility scores, and greater presenteeism (attending work while not physically or mentally capable of working), overall work impairment, activity impairment, HRU, indirect costs, and direct costs than the reference group. Despite the availability of AEDs during the year surveyed, a substantial number of patients experienced persistent seizures. Increasing seizure frequency was clearly associated with worse outcomes. The burden of PGTCS and IGE may be proportionally reduced by newer AEDs which may increase the proportion of seizure-free patients or shift more patients into lower seizure frequency categories
Ordered Phases of Itinerant Dzyaloshinsky-Moriya Magnets and Their Electronic Properties
A field theory appropriate for magnets that display helical order due to the
Dzyaloshinsky-Moriya mechanism, a class that includes MnSi and FeGe, is used to
derive the phase diagram in a mean-field approximation. The helical phase, the
conical phase in an external magnetic field, and recent proposals for the
structure of the A-phase and the non-Fermi-liquid region in the paramagnetic
phase are discussed. It is shown that the orientation of the helical pitch
vector along an external magnetic field within the conical phase occurs via two
distinct phase transitions. The Goldstone modes that result from the long-range
order in the various phases are determined, and their consequences for
electronic properties, in particular the specific heat, the single-particle
relaxation time, and the electrical and thermal conductivities, are derived.
Various aspects of the ferromagnetic limit, and qualitative differences between
the transport properties of helimagnets and ferromagnets, are also discussed.Comment: 22pp, 8 eps fig
Effect of NOx level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes
Secondary organic aerosol (SOA) formation from the photooxidation of one monoterpene (α-pinene) and two sesquiterpenes (longifolene and aromadendrene) is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NOx conditions. The NOx dependence of α-pinene SOA formation follows the same trend as that observed previously for a number of SOA precursors, including isoprene, in which SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) decreases as NOx level increases. The NOx dependence of SOA yield for the sesquiterpenes, longifolene and aromadendrene, however, differs from that determined for isoprene and α-pinene; the aerosol yield under high-NOx conditions substantially exceeds that under low-NOx conditions. The reversal of the NOx dependence of SOA formation for the sesquiterpenes is consistent with formation of relatively low-volatility organic nitrates, and/or the isomerization of large alkoxy radicals leading to less volatile products. Analysis of the aerosol chemical composition for longifolene confirms the presence of organic nitrates under high-NOx conditions. Consequently the formation of SOA from certain biogenic hydrocarbons such as sesquiterpenes (and possibly large anthropogenic hydrocarbons as well) may be more efficient in polluted air
The internal transcribed spacer rDNA specific markers for identification of Zanthoxylum piperitum
Genus Zanthoxylum which has significant medical importance belongs to the family Rutaceae. This investigation was aimed to identify total internal transcribed spacer (ITS) regions among the nuclear ribosomal DNA (nrDNA) to distinguish Zanthoxylum piperitum from Zanthoxylum sichinifolium. The nrDNA ITS sequence markers were developed by using universal ITS5/ITS4 primer pairs. Speciesspecific primers amplified the total ITS region sequence named ITS1-YL1 and ITS1-YL2. These were amplified efficiently when paired with universal primer ITS4 in Z. piperitum, but not in Z. schinifolium. ITS1-YL1/ITS4 or ITS1-YL2/ITS4 preferential amplification was shown to be particularly useful for detection and distribution of Z. piperitum from other plant species, especially Z. schinifolium. These primers are useful to study the structure of Rutaceae family. Such identifications will be helpful for phylogenetic analysis in intraspecies population of the genus Zanthoxylum.Key words: Zanthoxylum piperitum, rDNA Int-sp markers, phylogenetic relationship, ribosomal DNA, internal transcribed spacer
Ribosomal DNA internal transcribed spacer 1 and internal transcribed spacer 2 regions as targets for molecular identification of medically important Zanthoxylum schinifolium
Molecular approaches are now being developed to provide a more rapid and objective identification compared to traditional phenotypic methods. Nuclear ribosomal DNA (nrDNA) targets, especially internal transcribed spacer 1 and 2 (ITS1 and ITS2), have been widely used for molecular identification of some plants and fungi. We therefore conducted an investigation in the identification of the fifth medically important Zanthoxylum schinifolium ecotypes using the common primers of the ITS region. About 620 bp fragments were obtained and the sequences of the polymerase chain reaction (PCR) products were tested. The sequence length, G+C content (%), DNA alignment and pariwise nucleotidecomparisons demonstrated 98.8 to 100% sequence identities in the total ITS region, 98.3 to 100% identities in the ITS1 region and 99.5 to 100% in the ITS2 region. Comparative analysis using GenBank reference data showed that the exclusive reported data showed 100% identities with BEMR, CWDO, HCDC, JDGG and GJGD in the ITS1 region and 100% identities with thirteen ecotypes except BEMR and GRDG in the ITS2 region. The fifth different ecotypes were classified into five groups and theidentification of medically important Z. schinifolium was highly improved due to the augmentation of our current ITS sequences
- …