Macroeconomic framework for an oil-based economy : the case of Bahrain

Bahrain's economy is characterized by producer and consumer subsidies and, possibly misaligned currency. These subsidies have resulted in lower savings rates than would be consistent with the country's endowment in oil and gas. In addition, the misaligned real exchange rate has encouraged imports, at the same time creating incentives biased against the non-oil tradable sectors. So, Bahrain's economy remains largely dependent on a rapidly depleting hydrocarbon resource base. The authors espouse a macroeconomic consistency framework to focus on the behavior of Bahrain's economy along two paths. Part one is based on the assumption that the government's present macroeconomic policy will continue. In that case, the solution exhibits bubbles - fiscal and current account imbalances that would be unsustainable over time. Meanwhile, real appreciation of the dinar would suppress non-oil exports. As a result, the need for foreign borrowing would be more pressing. In an attempt to restore the equilibrium, the government would need to contain aggregate demand by compressing imports and investment, thereby worsening the economic situation. Path two is based on a reform strategy that includes policies to raise the domestic savings rate, improve the fiscal situation (by rationalizing expenditures and introducing income taxes and cost recovery measures), and correct the misaligned exchange rate. The results show that the expenditure-switching effect of the exchange rate alignment would shift resources in favor of the tradable sectors. Non-oil GDP and exports would register high growth rates while economic diversification, in the context of a growing and more dynamic economy, would foster investment efficiency. This would help Bahrainis maintain a high standard of living as the oil income dries up, without too much loss of consumption for the present generation.Economic Stabilization,Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,Macroeconomic Management

Bahrain - Managing a nonrenewable resource : savings and exchange-rate policies

Bahrain's oil-producing economy is vulnerable to terms-of-trade shocks for oil in the short to medium run. But the country's dependence on nonrenewable hydrocarbon resources represents a more basic constraint on Bahrain's prospects for long-term economic growth and welfare. To maintain economic growth and welfare in the post-oil era, Bahrain must save more of its oil revenues and assets and use them to invest abroad and to support economic diversification. The authors derive optimum domestic savings rates for Bahrain in the context of a two-assets (oil and non-oil) intertemporal welfare-maximizing model. Based on these derived rates, they recommend that the current suboptimal savings ratios be raised by about 10 percent of GDP. Achieving such a high savings rate is probably not economically feasible or politically sustainable in a stagnant economy, because it implies significantly reducing absolute levels of real consumption. Such austerity would not be necessary in a growing, efficiently restructured, and diversified economy, in which the real exchange rate policy played a key role by stimulating non-oil tradable sectors that could replace oil when it dries out. But the success of real exchange rate depreciation itself depends on a sufficiently high savings rate, to free up resources to switch to the production of other tradables. The authors present an empirical three-sector model of the real exchange rate, which permits links between the equilibrium real exchange rate and the optimum savings rate. They use this model to compute what real depreciation is required consistent with the derived optimum savings ratios. Their model predicts that a real depreciation of about 31 percent would be needed between 1992 and 2005 to avert serious overvaluation over this period.Macroeconomic Management,Environmental Economics&Policies,Economic Theory&Research,Banks&Banking Reform,Economic Stabilization

Exact solutions for a universal set of quantum gates on a family of iso-spectral spin chains

We find exact solutions for a universal set of quantum gates on a scalable candidate for quantum computers, namely an array of two level systems. The gates are constructed by a combination of dynamical and geometrical (non-Abelian) phases. Previously these gates have been constructed mostly on non-scalable systems and by numerical searches among the loops in the manifold of control parameters of the Hamiltonian.Comment: 1 figure, Latex, 8 pages, Accepted for publication in Physical Review

Hypertrophic pyloric stenosis, an unusual presentation and rare association: case report and literature review

Hypertrophic pyloric stenosis (HPS) is a commonly encountered surgical condition that occurs in infancy, but not in neonates. This report describes a 10-day-old male patient with atypical presentation of HPS, with an incidental diagnosis of eventration of the left diaphragm. The symptoms were present since birth with nonprojectile, nonbilious vomiting and gastric distension. A contrast study showed a gastric outlet obstruction with the possibility of gastric volvulus. Emergency surgery established the diagnosis. To the best of our knowledge, the association of HPS with diaphragmatic defect and gastric volvulus is rare, and few cases have been reported in the literature

Automatic Segmentation of the Left Ventricle in Cardiac CT Angiography Using Convolutional Neural Network

Accurate delineation of the left ventricle (LV) is an important step in evaluation of cardiac function. In this paper, we present an automatic method for segmentation of the LV in cardiac CT angiography (CCTA) scans. Segmentation is performed in two stages. First, a bounding box around the LV is detected using a combination of three convolutional neural networks (CNNs). Subsequently, to obtain the segmentation of the LV, voxel classification is performed within the defined bounding box using a CNN. The study included CCTA scans of sixty patients, fifty scans were used to train the CNNs for the LV localization, five scans were used to train LV segmentation and the remaining five scans were used for testing the method. Automatic segmentation resulted in the average Dice coefficient of 0.85 and mean absolute surface distance of 1.1 mm. The results demonstrate that automatic segmentation of the LV in CCTA scans using voxel classification with convolutional neural networks is feasible.Comment: This work has been published as: Zreik, M., Leiner, T., de Vos, B. D., van Hamersvelt, R. W., Viergever, M. A., I\v{s}gum, I. (2016, April). Automatic segmentation of the left ventricle in cardiac CT angiography using convolutional neural networks. In Biomedical Imaging (ISBI), 2016 IEEE 13th International Symposium on (pp. 40-43). IEE

Automatic calcium scoring in low-dose chest CT using deep neural networks with dilated convolutions

Heavy smokers undergoing screening with low-dose chest CT are affected by cardiovascular disease as much as by lung cancer. Low-dose chest CT scans acquired in screening enable quantification of atherosclerotic calcifications and thus enable identification of subjects at increased cardiovascular risk. This paper presents a method for automatic detection of coronary artery, thoracic aorta and cardiac valve calcifications in low-dose chest CT using two consecutive convolutional neural networks. The first network identifies and labels potential calcifications according to their anatomical location and the second network identifies true calcifications among the detected candidates. This method was trained and evaluated on a set of 1744 CT scans from the National Lung Screening Trial. To determine whether any reconstruction or only images reconstructed with soft tissue filters can be used for calcification detection, we evaluated the method on soft and medium/sharp filter reconstructions separately. On soft filter reconstructions, the method achieved F1 scores of 0.89, 0.89, 0.67, and 0.55 for coronary artery, thoracic aorta, aortic valve and mitral valve calcifications, respectively. On sharp filter reconstructions, the F1 scores were 0.84, 0.81, 0.64, and 0.66, respectively. Linearly weighted kappa coefficients for risk category assignment based on per subject coronary artery calcium were 0.91 and 0.90 for soft and sharp filter reconstructions, respectively. These results demonstrate that the presented method enables reliable automatic cardiovascular risk assessment in all low-dose chest CT scans acquired for lung cancer screening

Comparison of callus induction and somatic embryogenesis of some Iranian cottons (Gossypium Spp.) with Coker 312 and histology of somatic embryogenesis

Callus induction and somatic embryogenesis from hypocotyl explants of some Iranian cottons spp. (Hashem abad, Kerman, Termez and Sepid) were compared with Coker 312 through induction and formation of embryogenic calli on medium of Murashige and Skoog (MS) with Gamborg vitamins (B5) supplemented with the following compositions: MSB1 (0.5 mg/l zeatin), MSB2 (1 mg/l zeatin), MSB3 (0.5 mg/l 2,4-dichlorophenoxyacetic acid, 0.1 mg/l kinetin), MSB4 (1 mg/l 2,4-D, 0.5 mg/l kinetin, 0.5 mg/l zeatin) and MSB5 (2 mg/l α-naphtalene-3-acetic acid, 1 mg/l kinetin, 0.75 mg/l MgCl2). The optimum medium for the proliferation of embryogenic calli was MS medium containing B5 vitamins, 1 mg/l 2,4-D, 0.5 mg/l kinetin and 0.5 mg/l zeatin and the optimum medium for the development of somatic embryos was MS medium (NH4NO3 was removed and KNO3 amount doubled) containing B5 vitamins, 40 g/l sucrose and without hormone. Media MSB1, MSB2 and MSB4 gave the highest percentage (100%) of calli induction in Coker 312 but the lowest induction (46.66%) was observed when Hashem abad explants were cultured in the MSB3 medium. Embryogenesis percentage of Termez (2.22  to 24.40%), Hashemabad (1.85 to 9.73%) and Sepid (9.06 to 22.28%) genotypes were significantly lower than that of Coker 312 (66.66 to 94.33%). The Kerman genotype did not show embryogenesis. In the histological studies, the different development stages of the embryos (globular, heart, torpedo and cotyledonary) together with callus cells were showed.Key words: Hypocotyl explants, somatic embryo, in vitro regeneration, germination, somatic embryogenesis histology

Deep learning analysis of the myocardium in coronary CT angiography for identification of patients with functionally significant coronary artery stenosis

In patients with coronary artery stenoses of intermediate severity, the functional significance needs to be determined. Fractional flow reserve (FFR) measurement, performed during invasive coronary angiography (ICA), is most often used in clinical practice. To reduce the number of ICA procedures, we present a method for automatic identification of patients with functionally significant coronary artery stenoses, employing deep learning analysis of the left ventricle (LV) myocardium in rest coronary CT angiography (CCTA). The study includes consecutively acquired CCTA scans of 166 patients with FFR measurements. To identify patients with a functionally significant coronary artery stenosis, analysis is performed in several stages. First, the LV myocardium is segmented using a multiscale convolutional neural network (CNN). To characterize the segmented LV myocardium, it is subsequently encoded using unsupervised convolutional autoencoder (CAE). Thereafter, patients are classified according to the presence of functionally significant stenosis using an SVM classifier based on the extracted and clustered encodings. Quantitative evaluation of LV myocardium segmentation in 20 images resulted in an average Dice coefficient of 0.91 and an average mean absolute distance between the segmented and reference LV boundaries of 0.7 mm. Classification of patients was evaluated in the remaining 126 CCTA scans in 50 10-fold cross-validation experiments and resulted in an area under the receiver operating characteristic curve of 0.74 +- 0.02. At sensitivity levels 0.60, 0.70 and 0.80, the corresponding specificity was 0.77, 0.71 and 0.59, respectively. The results demonstrate that automatic analysis of the LV myocardium in a single CCTA scan acquired at rest, without assessment of the anatomy of the coronary arteries, can be used to identify patients with functionally significant coronary artery stenosis.Comment: This paper was submitted in April 2017 and accepted in November 2017 for publication in Medical Image Analysis. Please cite as: Zreik et al., Medical Image Analysis, 2018, vol. 44, pp. 72-8

Seasonal change of thyroid histomorphological structure and hormone production in yellowfin seabream (Acanthopagrus latus) in the Persian Gulf

Seasonal changes of the thyroid gland structure and hormones secretion was examined in yellowfin seabream (Acanthopagrus latus) in the northwest of Persian Gulf (Musa creek). Thyroid gland composed of follicles scattered around the ventral aorta, near the gills. Follicular cells varied according to secretion of the gland during warm and cold seasons. Thyroid hormones (Triidothyronine [T3] and Thyroxine [T4]) were detected in the fish serum in levels ranged from 4.09-1.30 ng/mL for T3 and from 1.10-0.21 ng/mL for (T4) in the warm and cold seasons, respectively. The results showed that the height of thyroid epithelium and plasma concentration of thyroid hormones (thyroid activity) in A. latus increased significantly during spring and summer. The peak of these factors occurred in midsummer (August). Then, the thyroid activity decreased significantly during autumn and early winter from October to December according to decrease of temperature. T3 and T4 increased significantly from January to April