Burden sharing in NATO

During the period of cold war, NATO alliance was producing defence commodity to protect its members from the common threat of ex-Soviet Union. The paper examines the problem of burden sharing among NATO allies. It is shown that larger countries are benefited more than smaller countries from the production of the public good i.e defence, if the income elasticity of marginal utility of income is greater than one in absolute value. Complete demand systems are employed for estimating the income elasticity of marginal utility of income.peer-reviewe

Simultaneous multi-frequency single-pulse properties of AXP XTE J1810-197

We have used the 76-m Lovell, 94-m equivalent WSRT and 100-m Effelsberg radio telescopes to investigate the simultaneous single-pulse properties of the radio emitting magnetar AXP XTE J1810-197 at frequencies of 1.4, 4.8 and 8.35 GHz during May and July 2006. We study the magnetar's pulse-energy distributions which are found to be very peculiar as they are changing on time-scales of days and cannot be fit by a single statistical model. The magnetar exhibits strong spiky single giant-pulse-like subpulses, but they do not fit the definition of the giant pulse or giant micropulse phenomena. Measurements of the longitude-resolved modulation index reveal a high degree of intensity fluctuations on day-to-day time-scales and dramatic changes across pulse phase. We find the frequency evolution of the modulation index values differs significantly from what is observed in normal radio pulsars. We find that no regular drifting subpulse phenomenon is present at any of the observed frequencies at any observing epoch. However, we find a quasi-periodicity of the subpulses present in the majority of the observing sessions. A correlation analysis indicates a relationship between components from different frequencies. We discuss the results of our analysis in light of the emission properties of normal radio pulsars and a recently proposed model which takes radio emission from magnetars into consideration.Comment: 15 pages, 11 figures, accepted for publication by MNRA

Endothelin receptor antagonists (ERA) in hypertension and chronic kidney disease: A rose with many thorns

The discovery of endothelin created a lot of enthusiasm and paved new therapeutic avenues for the treatment of arterial hypertension. Endothelin plays a significant role in blood pressure regulation through pronounced vasoconstriction and modulation of sodium and water reabsorption in the kidneys. Endothelin receptor antagonists have been tested in many clinical trials in patients with arterial hypertension, heart failure, pulmonary arterial hypertension, systemic sclerosis, chronic kidney disease, and diabetic nephropathy. However, the results were usually disappointing, except in pulmonary hypertension and scleroderma digital ulcers. The future of ERAs for the treatment of arterial hypertension and chronic kidney disease does not seem bright, and only the combination with other classes of antihypertensive drugs might offer a way out

Retro-oesophageal right subclavian artery in association with thyroid ima artery: a case report, clinical impact and review of the literature

A 37-year-old female Caucasian cadaver with an aberrant right subclavian artery extending from the left side of the aortic arch and following a retro-oesophageal course is presented. A non-recurrent right laryngeal nerve and a thyroid ima artery arising from the lower part of the middle third of the right common carotid artery coexisted. The brachiocephalic trunk was absent, while both common carotid arteries and left subclavian artery followed their normal course. The aim of the current study is to highlight the clinical impact of the above abnormalities providing useful and practically applicable knowledge to interventional clinicians, thoracic and neck surgeons, since the vast majority of documented cases with an arteria lusoria are clinically silent and in most cases discovered incidentally. Clinical manifestations such as dysphagia, chronic cough, and acute ischaemia to the right upper limb may occur, leading to misinterpretation in radiographic examination and complications during neck and thoracic surgery. Review of the literature was also performed and the embryological background of the aberration is highlighted

Ancient human genomes suggest three ancestral populations for present-day Europeans

We sequenced the genomes of a 7,000-year-old farmer from Germany and eight 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes¹-₄ with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations:west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians³, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry.We model these populations’ deep relationships and show that early European farmers had 44% ancestry from a ‘basal Eurasian’ population that split before the diversification of other non-African lineage

Isolated descemetorhexis for anterior synechiolysis prior to endothelial keratoplasty - case report and technique.

To describe the utilization of descemetorhexis for reformation of the anterior chamber in eyes with central iridocorneal synechiae before endothelial keratoplasty (EK). A 71-year-old man with a history of trabeculectomy complicated by hypotony presented with bullous keratopathy in the presence of extensive iridocorneal synechiae and a flat anterior chamber. In order to proceed with EK, synechiolysis with the use of viscoelastic and scissors was attempted. Despite successful dissection of the peripheral strands, the pupillary margin of the iris remained attached to the endothelium. Therefore, descemetorhexis was performed to detach the Descemet membrane along with central synechiae and create sufficient space for safe EK at a later stage. Corneal clarity was restored by ultrathin Descemet stripping automated endothelial keratoplasty, leaving a fibrous membrane in the pupillary plane, which was excised 2 months later, allowing an improvement of best-corrected visual acuity to 0.5. Isolated descemetorhexis was successfully employed to reform the anterior chamber and proceed with EK in a case of bullous keratopathy and resistant iridocorneal synechiae. This stepwise approach may be considered in similar cases in order to avoid a more invasive treatment, ie, penetrating keratoplasty and synechiolysis

Updates in the diagnosis and management of small-bowel Crohn's disease

Crohn's disease (CD) can affect any part of the GI tract, but small bowel (SB) involvement is present in 80% of patients with CD; 30% have exclusive SB disease [1] presenting a diagnostic challenge due to the inaccessibility of standard endoscopic techniques. Accurate assessment of treatment response [2] and regular monitoring are crucial to prevent surgery and to identify patients at risk of relapse and/or complications before the onset of clinical symptoms [3]. Ileocolonoscopy (IC) is considered the gold standard for evaluating mucosal healing (MH) in CD, but it is invasive and costly [4] and only allows visualization of the terminal ileum (TI). The CALM study has demonstrated that C-reactive protein (CRP) and faecal calprotectin (FCP) can be effective surrogate markers of MH and help guide treatment [5]. Nonetheless, their efficacy is limited [6] as approximately 30% of patients do not present with elevated CRP levels during relapse [7] and the correlation between FCP and active SB disease is weak [8]. Thus, CD requires a multidisciplinary approach. We aim to provide an overview of recent advances in the diagnosis and management of small bowel CD

Visible light communication based system using high power LED and dicode pulse position modulation technique

In this paper a dicode pulse position modulation (DiPPM) technique has been successfully implemented for an indoor visible light communication (VLC) based system using an FPGA and a commercial high power white LED (30W). A data rate of 13 Mbps has been achieved with a bit error rate (BER) <10-11 at a free space distance of 1.2 m through a basic transceiver circuit, and 14.5 Mbps with 1.15x10-6 of BER. Furthermore, a data rate of 13 Mbps has been successfully transmitted over a distance of 1.8 m with BER of 10-5. This proves that the application of DiPPM is a viable modulation system over free space communication links

Placing limits on the stochastic gravitational-wave background using European Pulsar Timing Array data

Direct detection of low-frequency gravitational waves ($10^{-9} - 10^{-8}$ Hz) is the main goal of pulsar timing array (PTA) projects. One of the main targets for the PTAs is to measure the stochastic background of gravitational waves (GWB) whose characteristic strain is expected to approximately follow a power-law of the form $h_c(f)=A (f/\hbox{yr}^{-1})^{\alpha}$, where $f$ is the gravitational-wave frequency. In this paper we use the current data from the European PTA to determine an upper limit on the GWB amplitude $A$ as a function of the unknown spectral slope $\alpha$ with a Bayesian algorithm, by modelling the GWB as a random Gaussian process. For the case $\alpha=-2/3$, which is expected if the GWB is produced by supermassive black-hole binaries, we obtain a 95% confidence upper limit on $A$ of $6\times 10^{-15}$, which is 1.8 times lower than the 95% confidence GWB limit obtained by the Parkes PTA in 2006. Our approach to the data analysis incorporates the multi-telescope nature of the European PTA and thus can serve as a useful template for future intercontinental PTA collaborations.Comment: 14 pages, 8 figures, 3 tables, mnras accepte