Military Expenditure, Endogeneity and Economic Growth

The debate over the economic effects of military spending continues to develop, with no consensus, but a deepening understanding of the issues and limitations of previous work. A recent survey has suggested that the inclusion of post Cold War data has tended to make finding a negative effect more common, but issues remain (Dunne and Tian, 2013). One particularly important issue that has not been adequately dealt with, is the possible endogeneity of military spending in the growth equation, mainly because of the difficulty of finding any variables that would make adequate instruments. This paper considers the likely importance of endogeneity, using conflict onset as an instrument for military spending in an endogenous growth model for a panel of African countries 1989-2010. Following a brief review of the literature the theoretical and empirical models are outlined and the use of conflict onset as an instrumental variable for military spending in the panel estimates is justified. The empirical analysis suggests that endogeneity is likely to be an important issue and using IV estimation provides a larger significant negative effect for military spending on growth than OLS. It also identifies a further potential bias in the same direction in studies not including non-military spending in the growth equation. These results imply that the damaging effects of military spending on growth in Africa are being underestimated in most studies. While it is clear that conflict onset is a suitable and successful instrument in this analysis, the results are not directly generalisable. Conflict onset is unlikely to be applicable to a larger and more diverse panel of countries. What is of general concern is the finding that endogeneity is important and is likely to be influencing the results of studies of military spending and growth. It is important that future research tries to deal with endogeneity and the search for reasonable instruments is one that needs to engage researchers

Military Expenditure, Endogeneity and Economic Growth

The debate over the economic effects of military spending continues to develop, with no consensus, but a deepening understanding of the issues and limitations of previous work. A recent survey has suggested that the inclusion of post Cold War data has tended to make finding a negative effect more common, but issues remain (Dunne and Tian, 2013). One particularly important issue that has not been adequately dealt with, is the possible endogeneity of military spending in the growth equation, mainly because of the difficulty of finding any variables that would make adequate instruments. This paper considers the likely importance of endogeneity, using conflict onset as an instrument for military spending in an endogenous growth model for a panel of African countries 1989-2010. Following a brief review of the literature the theoretical and empirical models are outlined and the use of conflict onset as an instrumental variable for military spending in the panel estimates is justified. The empirical analysis suggests that endogeneity is likely to be an important issue and using IV estimation provides a larger significant negative effect for military spending on growth than OLS. It also identifies a further potential bias in the same direction in studies not including non-military spending in the growth equation. These results imply that the damaging effects of military spending on growth in Africa are being underestimated in most studies. While it is clear that conflict onset is a suitable and successful instrument in this analysis, the results are not directly generalisable. Conflict onset is unlikely to be applicable to a larger and more diverse panel of countries. What is of general concern is the finding that endogeneity is important and is likely to be influencing the results of studies of military spending and growth. It is important that future research tries to deal with endogeneity and the search for reasonable instruments is one that needs to engage researchers

Measurement of the (30)Si Mole Fraction in the New Avogadro Silicon Material by Neutron Activation and High-Resolution γ-Spectrometry

The use of new silicon single crystals highly enriched in (28)Si recently produced for the upcoming redetermination of the Avogadro constant requires knowledge of their molar masses. The isotopic composition data are collected independently in different laboratories but all using the virtual element technique with multicollector inductively coupled plasma mass spectrometers. In this framework, the comparison of the results with an independent measurement of the amount of at least one of the depleted isotopes is useful to limit hidden systematic errors. To this aim, the (30)Si mole fraction of a sample of the new material was measured using a relative measurement protocol based on instrumental neutron activation analysis. The protocol is similar to that previously applied with the AVO28 silicon material used for the last determination of the Avogadro constant value with the exception that unknown and standard samples are not coirradiated. The x((30)Si) = 5.701 × 10(-7) mol mol(-1) estimate is close to the expected one and is given with a standard uncertainty of 8.8 × 10(-9) mol mol(-1). This value, if adopted, gives a contribution to the relative standard uncertainty of the Avogadro constant of 6.3 × 10(-10)

Carotid shunt provides cerebral protection during emergency coronary artery bypass grafting in a patient with bilateral high grade carotid stenosis: a case report

<p>Abstract</p> <p>Background</p> <p>Management of patients with co-existent coronary and carotid disease is a controversial and challenging issue. The risk for stroke after coronary artery bypass grafting (CABG) in patients with hemodynamically significant carotid stenosis is up to 30%. In these patients a common practice is to proceed first with the restoration of cerebral perfusion and then perform the coronary revascularization. The rationale is that this strategy will reduce perioperative neurological morbidity and mortality. However, what happens when the carotid procedure is acutely complicated by cardiac instability which necessitates the interruption of the carotid procedure?</p> <p>Case report</p> <p>We describe a case of a patient with unstable angina and high grade asymptomatic bilateral carotid stenosis who underwent emergency combined CABG and carotid endarterectomy (CEA). Due to hemodynamic instability, ST-T changes, hypotension and bradycardia, upon completion of endarterectomy we placed a carotid shunt and the patient was put on cardiopulmonary bypass through median sternotomy. After triple CABG (duration of 90 minutes) we concluded the interrupted CEA procedure with primary closure of the carotid arteriotomy with the shunt in place. The postoperative course was uneventful and the patient was discharged after a week. In extreme cases with bilateral severe carotid stenosis and coronary artery disease where the carotid procedure should be interrupted, we suggest the use of carotid shunt which can provide adequate cerebral perfusion giving time to cardiac surgeon to perform the life saving cardiac procedure first.</p

The effect of thoracic kyphosis and sagittal plane alignment on vertebral compressive loading

To better understand the biomechanical mechanisms underlying the association between hyperkyphosis of the thoracic spine and risk of vertebral fracture and other degenerative spinal pathology, we used a previously validated musculoskeletal model of the spine to determine how thoracic kyphosis angle and spinal posture affect vertebral compressive loading. We simulated an age-related increase in thoracic kyphosis (T1-T12 Cobb angle 50° to 75°) during two different activities (relaxed standing and standing with 5 kg weights in the hands) and three different posture conditions: 1) an increase in thoracic kyphosis with no postural adjustment (uncompensated posture), 2) an increase in thoracic kyphosis with a concomitant increase in pelvic tilt that maintains a stable center of mass and horizontal eye gaze (compensated posture), and 3) an increase in thoracic kyphosis with a concomitant increase in lumbar lordosis that also maintains a stable center of mass and horizontal eye gaze (congruent posture). For all posture conditions, compressive loading increased with increasing thoracic kyphosis, with loading increasing more in the thoracolumbar and lumbar regions than in the mid-thoracic region. Loading increased the most for the uncompensated posture, followed by the compensated posture, with the congruent posture almost completely mitigating any increases in loading with increased thoracic kyphosis. These findings indicate that thoracic kyphosis and spinal posture both influence vertebral loading during daily activities, implying that thoracic kyphosis measurements alone are not sufficient to characterize the impact of spinal curvature on vertebral loading

Solvent inhibition in the liquid-phase catalytic oxidation of 1,4-butanediol: understanding the catalyst behaviour from NMR relaxation time measurements

Catalytic reaction studies and Nuclear Magnetic Resonance (NMR) relaxation time measurements have been compared to study the influence of competitive adsorption of reactant and solvent on catalytic conversion. The reaction chosen is the aerobic catalytic oxidation of 1,4-butanediol in methanol over different supported-metal catalysts. From the NMR T1/T2 ratio, where T1 is the longitudinal and T2 the transverse spin relaxation time, the relative affinity of reactant and solvent for different catalytic surfaces is determined. The catalysts with the lowest activity show a preferential surface affinity for the solvent compared to the reactant. Conversely, the catalyst with the highest activity shows a preferential surface affinity for the reactant compared to the solvent. Significantly, Ru/SiO2, which is totally inactive for the oxidation of 1,4-butanediol, exhibited a lower T1/T2 ratio (surface affinity) for 1,4-butanediol (reactant) than for a “weakly-interacting” alkane, indicating a very poor surface affinity for the diol functionality. The results provide direct evidence of the importance of the adsorbate-adsorbent interactions on catalyst activity in liquid-phase oxidations and indicate that the competitive adsorption of the solvent plays an important role in these reactions. This work demonstrates that NMR relaxation time analysis is a powerful method for comparing adsorption of liquids in porous catalysts, providing valuable information on the affinity of different chemical species for a catalyst surface. Moreover, the results demonstrate that NMR relaxation time measurements can be used not only to guide selection of solvent for use with a specific catalyst, but also selection of the catalyst itself. The results suggest that this method may be used to predict catalyst behaviour, enabling improved design and optimisation of heterogeneous catalytic processes

Genetics and Epigenetics of Bone Remodeling and Metabolic Bone Diseases

Bone metabolism consists of a balance between bone formation and bone resorption, which is mediated by osteoblast and osteoclast activity, respectively. In order to ensure bone plasticity, the bone remodeling process needs to function properly. Mesenchymal stem cells differentiate into the osteoblast lineage by activating different signaling pathways, including transforming growth factor β (TGF-β)/bone morphogenic protein (BMP) and the Wingless/Int-1 (Wnt)/β-catenin pathways. Recent data indicate that bone remodeling processes are also epigenetically regulated by DNA methylation, histone post-translational modifications, and non-coding RNA expressions, such as micro-RNAs, long non-coding RNAs, and circular RNAs. Mutations and dysfunctions in pathways regulating the osteoblast differentiation might influence the bone remodeling process, ultimately leading to a large variety of metabolic bone diseases. In this review, we aim to summarize and describe the genetics and epigenetics of the bone remodeling process. Moreover, the current findings behind the genetics of metabolic bone diseases are also reporte

Product inhibition in the glycerol oxidation over Au/TiO2 catalyst quantified by NMR relaxation

Liquid-phase catalytic oxidation of glycerol in aqueous solutions using porous solid catalysts represents a viable strategy for the sustainable production of fine chemicals from renewable resources. Various aspects of this novel type of reactions are still under investigation. Catalyst deactivation is one of those issues that need to be understood and addressed in order to make these processes commercially viable. In a previous study it has been reported that the catalytic activity of Au/TiO2 catalysts for the oxidation of glycerol with O2 under basic conditions can be severely inhibited by some reaction intermediates or products. It was suggested that the presence of certain species blocks the active sites of the catalyst, preventing the adsorption of glycerol, which in turn results in a decrease of reaction rate. In this work, we used NMR relaxation time measurements in order to assess surface interactions of glycerol in Au/TiO2 catalyst pre-treated with aqueous solutions of various oxygenates, including intermediates and products of glycerol oxidation, under basic conditions, in particular evaluating changes in glycerol adsorption properties. The NMR T1/T2 ratio of glycerol, which is indicative of the strength of interaction of glycerol with the catalyst surface, traces out well the trend in catalytic activity in the presence of different additives, suggesting that adsorption of glycerol onto the catalyst surface play a crucial role in the reaction, which supports the hypothesis previously made in the literature. This experimental approach and the related results represent a significant advance in the understanding of liquid-phase catalytic reactions occurring over solid surfaces, which can be used to understand and optimise catalytic processes and the effect of intermediate and product inhibition

Separation of Test-Free Propositional Dynamic Logics over Context-Free Languages

For a class L of languages let PDL[L] be an extension of Propositional Dynamic Logic which allows programs to be in a language of L rather than just to be regular. If L contains a non-regular language, PDL[L] can express non-regular properties, in contrast to pure PDL. For regular, visibly pushdown and deterministic context-free languages, the separation of the respective PDLs can be proven by automata-theoretic techniques. However, these techniques introduce non-determinism on the automata side. As non-determinism is also the difference between DCFL and CFL, these techniques seem to be inappropriate to separate PDL[DCFL] from PDL[CFL]. Nevertheless, this separation is shown but for programs without test operators.Comment: In Proceedings GandALF 2011, arXiv:1106.081

Age at quitting smoking as a predictor of risk of cardiovascular disease incidence independent of smoking status, time since quitting and pack-years

Background: Risk prediction for CVD events has been shown to vary according to current smoking status, pack-years smoked over a lifetime, time since quitting and age at quitting. The latter two are closely and inversely related. It is not known whether the age at which one quits smoking is an additional important predictor of CVD events. The aim of this study was to determine whether the risk of CVD events varied according to age at quitting after taking into account current smoking status, lifetime pack-years smoked and time since quitting. Findings. We used the Cox proportional hazards model to evaluate the risk of developing a first CVD event for a cohort of participants in the Framingham Offspring Heart Study who attended the fourth examination between ages 30 and 74 years and were free of CVD. Those who quit before the median age of 37 years had a risk of CVD incidence similar to those who were never smokers. The incorporation of age at quitting in the smoking variable resulted in better prediction than the model which had a simple current smoker/non-smoker measure and the one that incorporated both time since quitting and pack-years. These models demonstrated good discrimination, calibration and global fit. The risk among those quitting more than 5 years prior to the baseline exam and those whose age at quitting was prior to 44 years was similar to the risk among never smokers. However, the risk among those quitting less than 5 years prior to the baseline exam and those who continued to smoke until 44 years of age (or beyond) was two and a half times higher than that of never smokers. Conclusions: Age at quitting improves the prediction of risk of CVD incidence even after other smoking measures are taken into account. The clinical benefit of adding age at quitting to the model with other smoking measures may be greater than the associated costs. Thus, age at quitting should be considered in addition to smoking status, time since quitting and pack-years when counselling individuals about their cardiovascular risk