The Impact of Oil Shocks on Exchange Rates: The Case of Selected OPEC Countries

OPEC countries are heavily dependent on oil dollar revenues through which impact on exchange rates. The purpose of this study is to investigate the effect of oil shocks on the real exchange rates for selected OPEC countries for the period 1980-2018. The oil shocks are first obtained using the vector auto-regression model and then their effects on the exchange rates are estimated using a panel quantile regression model. The results show that effect of oil shocks on exchange rates varies across quantiles. The oil specific-demand shock and global demand shock have a negative and significant effect on the real exchange rates while the oil supply shock has a positive and significant effect on the real exchange rates in OPEC countries. Furthermore, oil specific-demand shock has the most impact on the real exchange rates

Genetic, magnetic resonance imaging and body fluid biomarker associations with severity of multiple sclerosis

Multiple sclerosis is a chronic and progressive neuroinflammatory disease that leads to demyelination and neurodegeneration in the central nervous system (CNS). Previous research has identified a wide range of environmental, lifestyle and genetic factors which increase MS susceptibility. However, the pathomechanisms that influence the severity of MS are largely unknown, and adequate biomarkers of disease severity are consequently lacking. Therefore, the aim of my thesis was to; 1) assess associations between the nerve injury biomarker neurofilament light (NfL) and brain atrophy and lesion volumes; 2) assess which brain/lesion volume measures show the strongest longitudinal association with clinical MS disability measures and to what degree these associations were affected by age; and to 3) identify genetic variants associated with brain atrophy, lesion volumes and plasma NfL (pNfL) levels in persons with MS. In Study I, we assessed how cerebrospinal fluid (CSF) and pNfL levels were associated with T1- and T2-lesion volumes as well as whole-brain, cortical and subcortical grey matter, white matter and thalamic volume fractions of total intracranial volume based on magnetic resonance imaging (MRI). High baseline CSF and pNfL levels were associated with lower whole-brain, subcortical grey matter, thalamic, white matter and corpus callosal volume fractions over time. A further analysis showed that there was an association between baseline pNfL and baseline cortical grey matter fractions also in absence of radiological signs of inflammatory disease activity. A topographic analysis of cortical thickness showed that loss of cortical volume preferentially involved frontotemporal cortical regions. These findings indicate that NfL levels contribute information about MS severity not provided by traditional MRI lesion metrics. In Study II, we showed that associations between baseline MRI variables, and baseline physical disability and self-reported impact of MS rapidly increased in strength in individuals beyond approximately 40-50 years of age. In separate longitudinal analyses using linear mixed-effects models, we showed that among the recorded brain volume measures, cortical and subcortical grey matter and thalamic volume fractions at baseline were the strongest predictors of future worsening in clinical disability over a median of approximately ten years’ follow-up time. They were also stronger predictors than T1- and T2-lesion volumes. In Study III, we assessed if a weighted risk score comprising 12 known MS risk human leukocyte antigen (HLA) alleles was associated with baseline and longitudinal MRI measures as described in Studies I and II. While this risk score was not significantly associated with baseline MRI measures, we found that a high score was associated with lower cortical grey matter fractions longitudinally. A further analysis showed that this effect was primarily driven by the HLA-DRB1*15:01 allele. These results suggest that MS HLA risk variants not only affect inflammatory, but also neurodegenerative aspects of the disease. In Studies IV and V, we performed genome-wide association studies of pNfL levels and whole-brain volume fractions, respectively, in persons with MS (and controls in Study IV). While no genome-wide significant associations were found in Study IV, gene set analyses highlighted a neural crest and odontogenesis development pathway in the regulation of pNfL levels, and a weighted MS susceptibility polygenic risk score was associated with higher pNfL levels in MS with statistical significance. These findings suggest that there is some degree of genetic regulation of pNfL levels, which partially overlap with MS risk. In Study V, we identified a genome-wide significant locus upstream of the glycerol kinase 2 (GK2) gene, previously implicated in the propensity for tobacco smoking, which is a known MS risk and severity factor. Gene set analyses in Study V also implicated Hypoxia Inducible Factor-1 (HIF1) in the regulation of whole-brain volume fractions, indicating that iron metabolism and response to hypoxia play a role in the neurodegenerative processes in MS

The Effect of Financial Leverage on the Growth of the Companies Listed in Tehran Stock Exchange

This study examines the effect of financial leverage on the growth of companies listed in Tehran Stock Exchange. The study population includes pharmaceutical companies listed in Tehran Stock Exchange. The study interval is 2010-2014. Using variable data software brings a new approach, and is calculated by Excel. Variables of the study were calculated by data of Rahavard Novin Software and Excel. Data was analyzed by SPSS using descriptive and inferential statistics such as the Kolmogorov-Smirnov test, Pearson correlation and linear regression in order to test hypotheses of the study. According to the tests and analyses, it could be concluded that hypotheses were accepted. Thus, we can claim that there was an inverse relationship between leverage and company's growth

Underground Mining Monitoring and Communication Systems based on ZigBee and GIS

ZigBee as a wireless sensor network (WSN) was developed for underground mine monitoring and communication systems. The radio wave attenuations between ZigBee nodes were investigated to measure underground communication distances. Various sensor node arrangements of ZigBee topologies were evaluated. A system integration of a WSN-assisted GIS for underground mining monitoring and communication from a surface office was proposed. The controllable and uncontrollable parameters of underground environments were assessed to establish a reliable ZigBee network

Annotation of grammatical function in the Persian treebank

AbstractIn this paper we present and justify methodological principles and syntactic criteria to design an annotation scheme for a Persian Treebank. The advantages of the proposed scheme for annotation of the Persian Treebank will be discussed. At the same time, we present the way that different types of linguistic knowledge (morphological, syntactic and semantic) are encoded in the structures of the schema. We will show how this scheme can account for many of the syntactic constructions that appear to be unique to the Persian language

Reversible supramolecular modification of surfaces

Enzymes are biocatalysts widely used in a large number of industrial biotech processes as they offer clear advantages over their chemical counterparts. Indeed, enzymes often show high substrate selectivity along with elevated turnover rates. Enzymatic catalysis usually functions under mild conditions of temperature, pressure and acidity. However, the industrial application of enzymes is often limited by their limited stability under operational conditions. Moreover, due to high water solubility of enzymes it is challenging to confined them in a flow reactor system. In order to circumvent these limitations, we have developed a supramolecular strategy that allows the reversible immobilization of active enzyme-polymer conjugates at the surface of filtration membranes. It is based on multivalent host-guest inclusion interactions between the membrane surface and a soluble enzyme-polymer conjugate. Cyclodextrins (CDs) as "host" molecules are covalently attached at the surface of polyethersulfone membranes and a multivalent water-soluble polymer is synthesized as a "guest" molecule. We demonstrate that while this supramolecular surface modification is stable under operational conditions and allows for efficient bio-catalysis, it can be straightforwardly reverse by competitive host-guest interactions. The first part of this manuscript is dedicated to a literature review on selected topics. As the supramolecular strategy we have developed in the course of this PhD research work is based on the use of cyclodextrins as supramolecular host molecules, the first part of this literature review focuses on the physico-chemical characteristics of this class of macrocycles. A special emphasis is done on their ability to form host-guest multivalent inclusion complexes. In this context, we describe the concept of multivalency and the underpinning essential thermodynamic principles, which can be apply to design controllable, directional, and selective self-assemblies. In the second part of this manuscript, we present our strategy to bio-functionalize polymeric membrane surfaces using multivalent reversible inclusion reactions. In more details, the chemical strategy to introduce CD macrocycles, in a covalent fashion, at the surface of the polymeric material is discussed. The synthesis and characterization of an enzyme-polymer conjugate, possessing multiple chemical functional groups (i.e. adamantyl) able to form inclusion complexes with CDs, is presented. It is demonstrated that this supramolecular strategy could be applied to the reversible immobilization of an active enzyme at the surface of polyethersulfone membranes. A similar strategy is applied to the reversible bio-functionalization of gold surfaces and used to prepare sensor chips for surface plasmon resonance (SPR) experiments. Self-assembled monolayers of CDs derivatives are prepared on the surface of a gold sensor chip. A water-soluble protein-polymer conjugate, possessing multiple adamantyl moieties, is synthesized. The supramolecular reversible binding of this new conjugate on the chemically modified SPR chip is demonstrated. The possibility to use this system for antigen/antibody biosensing experiment is successfully confirmed

Management of Molar Pregnancy During COVID-19 Pandemic

Molar pregnancy is a group of diseases called gestational trophoblastic disease (GTD) that originates in the placenta and has the potential to invade the uterus and metastasize locally1, 2. During the past months, the novel coronavirus disease 2019 (COVID-19) has been responsible for the worldwide pandemic3.  Patients usually go to the hospital only if they need high emergency aid or have a high-risk condition in this quarantine situation. Hence, this situation can impact diagnosing and managing benign and malignant molar pregnancy, and the diagnosis might be delayed