274 research outputs found
An analysis of the OPEC and non-OPEC position in the World Oil Market: A fractionally integrated approach.
This paper deals with the analysis of the world, OPEC and non-OPEC oil production by testing the degree of persistence of the series throughout fractional integration. The analysis is relevant in the sense that it allows us to determine if shocks in the series have permanent or transitory effects. The results indicate evidence of mean reversion in the three series, especially for the world and OPEC production. We also notice evidence of multiple breaks though the degree of persistence seems to be relatively stable across the subsamples, with most of the values in the range [0.5, 1) implying non-stationary and mean reverting behavior.pre-print603 K
The validity and reliability of autism behavior checklist in Iran
Objectives: The aim of this study was to evaluate the psychometric features of the Persian version of the Autism Behavior Checklist (ABC). Method: The International Quality of Life Assessment (IQOLA) approach was used to translate the English ABC into Persian. A total sample of 184 parents of children including 114 children with autism disorder (mean age =7.21, SD =1.65) and 70 typically developing children (mean age = 6.82, SD =1.75) completed the ABC. Internal consistency, test-retest reliability, concurrent and discriminant validity, and cut-off score were assessed. Results: The results of this study revealed that the Persian version of the ABC has an acceptable degree of internal consistency (.73). Test-retest comparisons using interclass correlation confirmed the instrument's time stability (.83). The instrument's concurrent validity with Gilliam Autism Rating Scale (GARS) was verified; the correlation between total scores was .94. In the discriminant validity, the autism group had significantly higher scores compared to the normal group. Receiver Operating Characteristic (ROC) analysis revealed that individuals with total scores below 25 are less likely to be in the autism group. Conclusion: The Persian version of the ABC can be used as an initial screening tool in clinical contexts
Antibacterial activity of certain Iranian medicinal plants against methicillin-resistant and sensitive Staphylococcus aureus
Bacterial resistance to antibiotics is a serious global problem and includes strains of beta-lactam-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Novel antimicrobials and/or new approaches to combat the problem are urgently needed. The aim of this study was to investigate the antimicrobial activity of alcoholic and aqueous extract of 23 medical plants species of Golestan province on clinical and standard stains of MRSA and MSSA. Twenty three medicinal plants were collected from their natural habitat in Golestan province in north of Iran. Their ethanolic and aqueous extract obtained by percolation methods. Antibacterial effects were assessed by disk diffusion method and the Minimum Inhibitory Concentration (MIC) of the extracts was determined by the micro broth dilution against 14 clinical and standard strains of methicillin resistant and sensitive of Staphylococcus aureus. The ethanolic and aqueous extract of 8, 3 plants showed best anti staphylococcal effect, respectively. The ethanolic extract of Artemisia, herbaalba, Nigella sativa, Punica granatum, possed the most outstanding in vitro antibacterial activity which the maximum inhibition zone was 22.4-18 mm, respectively and the lowest MIC values was measured in Punica granatum, as 0.01 mg mL-1 against MRSA The results showed that ethanolic extract had better antibacterial effect than aqueous extract and anti staphylococcal activity of Ethanolic extract of plants against MRSA was better than MSSA strains. Ethanolic and aqueous extract of Punica granatum had the best antibacterial activity against the tested microorganisms. The result obtained from these plants might be considered sufficient for further studies. © 2006 Asian Network for Scientific Information
Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation
Mitochondrial activity inhibits proliferation and is required for differentiation of myoblasts. Myoblast proliferation is also inhibited by the ~20% oxygen level used in standard tissue culture. We hypothesize that mitochondrial activity would be greater at hyperoxia (20% O(2)) relative to more physiological oxygen (5% O(2)).Murine primary myoblasts from isolated myofibres and conditionally immortalized H-2K myoblasts were cultured at 5% and 20% oxygen. Proliferation, assayed by cell counts, EdU labeling, and CFSE dilution, was slower at 20% oxygen. Expression of MyoD in primary myoblasts was delayed at 20% oxygen, but myogenicity, as measured by fusion index, was slightly higher. FACS-based measurement of mitochondrial activity indicators and luminometric measurement of ATP levels revealed that mitochondria exhibited greater membrane potential and higher levels of Reactive Oxygen Species (ROS) at 20% oxygen with concomitant elevation of intracellular ATP. Mitochondrial mass was unaffected. Low concentrations of CCCP, a respiratory chain uncoupler, and Oligomycin A, an ATP synthase inhibitor, each increased the rate of myoblast proliferation. ROS were investigated as a potential mechanism of mitochondrial retrograde signaling, but scavenging of ROS levels by N-acetyl-cysteine (NAC) or α-Phenyl-N-tert-butylnitrone (PBN) did not rescue the suppressed rate of cell division in hyperoxic conditions, suggesting other pathways. Primary myoblasts from older mice showed a slower proliferation than those from younger adult mice at 20% oxygen but no difference at 5% oxygen.These results implicate mitochondrial regulation as a mechanistic explanation for myoblast response to oxygen tension. The rescue of proliferation rate in myoblasts of aged mice by 5% oxygen suggests a major artefactual component to age-related decline of satellite cell proliferation in standard tissue culture at 20% oxygen. It lends weight to the idea that these age-related changes result at least in part from environmental factors rather than characteristics intrinsic to the satellite cell
Electronic excitations stabilized by a degenerate electron gas in semiconductors
Excitons in semiconductors and insulators consist of fermionic subsystems, electrons and holes, whose attractive interaction facilitates bound quasiparticles with quasi-bosonic character. In the presence of a degenerate electron gas, such excitons dissociate due to free carrier screening. Despite their absence, we found pronounced emission traces in the below-band-edge region of bulk, germanium-doped GaN up to a temperature of 100 K, mimicking sharp spectral features at high free electron concentrations (3.4E19–8.9E19 cm−3). Our interpretation of the data suggests that a degenerate, three-dimensional electron gas stabilizes a novel class of quasiparticles, which we name collexons. These many-particle complexes are formed by exchange of electrons with the Fermi gas. The potential observation of collexons and their stabilization with rising doping concentration is enabled by high crystal quality due to the almost ideal substitution of host atoms with dopants.DFG, 43659573, SFB 787: Semiconductor Nanophotonics: Materials, Models, Device
The study of nutrition and feeding position of shrimp, cultured in IRAN
The culture of Iranian Shrimps began in Bushehr in 1372. Early the green or the pink tiger shrimp (Penaeus semisulcatus) which were found in most habitats of the Persian Gulf and Oman Sea were considered in breeding and reproduction, but due to reproduction difficulties, it was rather replaced by the Monodun imported species, then the production of the white shrimp Metapenaeus affinis and Then P.merguensis in some southern areas of the country such as Hormozgan has began in small scale,but none of these species couldn't meet the economical needs of the consumer society and they were not indelible and dominant enough in the shrimp aquaculture industry of the country until breeding of Indian White Shrimp (Fenneropenaeus indicus) has began in large scale in the provinces of Khuzestan and Bushehr, which are seen as the heart of shrimps reproduction and breeding, and in Hormozgan and Sistan. the incidence of white spot viral syndrome (White Spot Syndrom Virus) led to the import of the western white leg shrimp from the USA (P.vannameii) by the Iranian Fisheries Research Organization (IFRO) in 1383, at the present all southern and northern breeding farms of the country (fundamental measures has been carried out in line of shrimp reproduction in Gorgan province in 1386) has put the breeding of this shrimp species as the single breeding species at top of their agenda. The subject of feeding the breeding shrimps is widespread and regarding to the non-proprietary species there are still some species which contain high protein than the other species in studying the different shrimp species requirements. In Iran due to the scarce factories producing the shrimp's food, the alimentary compound of the breeding shrimps during industrializing years of this type of breeding even after the non-aboriginal western white leg shrimp species being inclusive was stable and through different biological processes including: Naplies which feeds from its yalk and by entry into zoa stage start eating only small-sized phytoplankton. And by entry into the stage between zoa and mysis it feeds from phyto and zooplankton simultaneously and entering the post-larva stage it stars sarcophagi. and after 15 post-larva stage entering the growth and transition stage to earthen ponds feeding by concentrated industrial foods in large and small packages depending on young and adult mouth and due to feeding requirements of every stage the alimentary compound is nearly as follows: Digestible protein, energy, fat, carbohydrates, vitamins and minerals will start and the final product will be released in market Or they will be used in the later years of laying eggs and feeding for brood stock. In feeding section the details of every stage and their food's nutritional needs at each stage and will be fully described
Erratum: Incidental Detections Suggestive of COVID-19 in Asymptomatic Patients Undergoing 68Ga-DOTATATE and 68Ga-PSMA-11 PET-CT Scan for Oncological Indications (Nuklearmedizin (2020) DOI: 10.1055/a-1311-2856)
In the above article, an incorrect figure 2 was depicted. The mistake has been fixed in the meantime. The corrected figure presents below. (Figure Presented)
[Incidental Detections Suggestive of COVID-19 in Asymptomatic Patients Undergoing 68Ga-DOTATATE and 68Ga-PSMA-11 PET-CT Scan for Oncological Indications] [COVID-19 Zufallsbefund bei asymptomatischen Patienten mit 68Ga-DOTATATE und 68Ga-PSMA-11 PET-CT-Untersuchung aufgrund onkologischer Indikation]
- …