How should emerging economies manage their foreign exchange reserves?

Asia has emerged as the balancing wheel of global finance. The countries of Asia now account for 70 per cent of global foreign exchange reserves, compared to only 30 percent in 1990 and 21 per cent in the early 1970s. This paper explores theoretical interpretations for the relatively high demand for international reserves by developing countries especially in the Far East. This paper provides calculations of the minimal necessary level of international reserves based on benchmarks proposed by Wijnholds and Kapteyn, as well as a discussion of costs of reserves’ holding. It therefore provides empirical proof that exchange reserve levels for many of the developing countries have far exceeded the desirable levels. Paper then discusses the steps that central banks in these developing countries can take for an effective reserve management.Foreign exchange ; emerging economies; reserves; reserve level; east asia

Calf Muscle Strain: Injury of the Gastronemius and Soleus

CLINICAL PRESENTATION & EXAM: Calf strains are usually the result of a sudden pushing off movement or over-stretching of the muscle and usually afflict athletes and others later in life. They occur more in men than women, and afflicted patients tend to report calf tightness days before the injury. During the patient history, the patient usually presents with a sharp pain at the back of the lower leg and has pain and weakness in active plantarflexion. Additionally, the patient should be observed for swelling, bruising, and overpronation. Resisted muscle tests and functional tests can be conducted, and if needed, special tests such as Thompson’s test for complete muscle rupture should be conducted in which the foot will plantar flex if the calf muscle is squeezed and the Achilles tendon is intact. ANATOMY & PATHOLOGY: The calf muscle consists of the big gastrocnemius muscle at the back of the lower leg and the soleus muscle that is smaller and is below and covered by the gastrocnemius. The gastrocnemius originates from the medial and lateral condyles of the femur bone, above the knee joint, and inserts into the heel through the Achilles tendon to the calcaneus. It is innervated by the tibial nerve and has the primary action of plantarflexion of the foot and secondary action of flexion at the knee. The soleus originates below the knee from the tibia and fibula and also inserts to the heel through the Achilles tendon. It shares the same innervation and plantarflexes the foot. Calf strains are commonly found in the medial head of the gastrocnemius, and the muscle as a whole is considered high risk because it crosses both the ankle and knee joints and has a high density of type II fast twitch muscle fibers, causing rapid and forceful contractions. The soleus is considered lower risk for injury and crosses only the ankle joint. Soleus muscle damage usually occurs lower in the leg and is not painful when bending the knee. DIAGNOSTIC TESTING & CONSIDERATIONS: Differential diagnosis of a gastrocnemius versus a soleus injury in a calf strain can be done through palpation and strength and flexibility testing. When palpating, tenderness in the musculotendinous junction indicates a gastrocnemius injury, whereas soleus strain pain is more lateral. Additional, gastrocnemius and soleus strains can be distinguished by plantarflexing the foot at varying degrees of knee flexion. In maximal flexion at the knee the soleus primarily plantarflexes, and in full extension the gastrocnemius is the primary plantarflexor. In addition to resisted, functional, and special tests on the calf muscle, imaging tests such as ultrasound and MRI may be needed as well to see the actual rupture or damage to the muscle. MRI can also show hematomas, which sometimes occur following serious injuries. TREATMENT & RETURN TO ACTIVITY: Calf muscle strains are graded from I-III, representing the degree of muscle fiber tear: \u3c10%, 10%-50%, and \u3e50%, respectively. The treatment depends on the grade; however in general the RICE technique should be utilized – rest, ice, compress, elevate – after which gentle stretching and massage can help ease the swelling and relax the muscle. In addition, a compression bandage or crutches should be used as needed. After some time, calf strain strengthening and rehabilitative exercises should be employed in the order of isometric, isotonic, and then dynamic contractions alongside passive stretching. NSAID’s should be restricted for first few days after which COX-2 inhibitors are an option. Acetaminophen or narcotic pain medication can also be used. If the strain is grade III, surgery may be required to reattach the damaged muscle and tendon

The Effects of Option Expiration on NSE volume and prices

This paper studies the effect of stock options expiration day on the underlying shares traded on the National Stock Exchange (NSE). Overall we tested for abnormal trading volume, abnormal price movement, individual stock reversal and stock pinning on expiration days. To the best of our knowledge, this is a first such study done on the Indian market.option expiration, indian market, nse, abnormal trading volume, abnormal price movement, individual stock reversal, stock pinning, stock price clustering

Discrete Element Study Mixing in an Industrial Sized Mixer

The mixing quality as function of the operating time is one major parameter to be considered for the design of industrial sized mixers. Different mixer types with different operating principles can be found for different special tasks, and the question about the proper quantity that quantifies mixing is still open.\ud \ud Computer simulations based on the Discrete Element Method (DEM) provide a close,\ud detailed look inside the mixing device and process and thus a better understanding of the particle flow in the mixer. Therefore such simulations can be used for an improvement of the mixer design or operating conditions.\ud \ud DEM simulations allow the “online”- and “inline”-measurement of the mixing quality over time. But in mixers with a complex design it is not only interesting at which time a certain mixing quality is reached. It is also interesting to analyse which part of the mixing (either location in the device or process conditions) are of special importance due to a strong effect on the mixing process.\ud \ud Therefore, a time- and space-dependent analysis was developed, using several approaches for mixing-quality that can be found in literature. More explicitly, the particle numbers, the number of contacts between different particle-types, and the generalized mean mixing index (GMMI) have been examined. All have their regimes of reasonable use that will be discussed - the most promising approaches will be compared

Multimapper: Data Density Sensitive Topological Visualization

Mapper is an algorithm that summarizes the topological information contained in a dataset and provides an insightful visualization. It takes as input a point cloud which is possibly high-dimensional, a filter function on it and an open cover on the range of the function. It returns the nerve simplicial complex of the pullback of the cover. Mapper can be considered a discrete approximation of the topological construct called Reeb space, as analysed in the $1$-dimensional case by [Carriere et al.,2018]. Despite its success in obtaining insights in various fields such as in [Kamruzzaman et al., 2016], Mapper is an ad hoc technique requiring lots of parameter tuning. There is also no measure to quantify goodness of the resulting visualization, which often deviates from the Reeb space in practice. In this paper, we introduce a new cover selection scheme for data that reduces the obscuration of topological information at both the computation and visualisation steps. To achieve this, we replace global scale selection of cover with a scale selection scheme sensitive to local density of data points. We also propose a method to detect some deviations in Mapper from Reeb space via computation of persistence features on the Mapper graph.Comment: Accepted at ICDM

A Null-model Exhibiting Synchronized Dynamics in Uncoupled Oscillators

The phenomenon of phase synchronization of oscillatory systems arising out of feedback coupling is ubiquitous across physics and biology. In noisy, complex systems, one generally observes transient epochs of synchronization followed by non-synchronous dynamics. How does one guarantee that the observed transient epochs of synchronization are arising from an underlying feedback mechanism and not from some peculiar statistical properties of the system? This question is particularly important for complex biological systems where the search for a non-existent feedback mechanism may turn out be an enormous waste of resources. In this article, we propose a null model for synchronization motivated by expectations on the dynamical behaviour of biological systems to provide a quantitative measure of the confidence with which one can infer the existence of a feedback mechanism based on observation of transient synchronized behaviour. We demonstrate the application of our null model to the phenomenon of gait synchronization in free-swimming nematodes, C. elegans

Direct Observation of Unusual Interfacial Dzyaloshinskii-Moriya Interaction in Graphene/NiFe/Ta Heterostructure

Graphene/ferromagnet interface promises a plethora of new science and technology. The interfacial Dzyaloshinskii Moriya interaction (iDMI) is essential for stabilizing chiral spin textures, which are important for future spintronic devices. Here, we report direct observation of iDMI in graphene/Ni80Fe20/Ta heterostructure from non-reciprocity in spin-wave dispersion using Brillouin light scattering (BLS) technique. Linear scaling of iDMI with the inverse of Ni80Fe20 thicknesses suggests primarily interfacial origin of iDMI. Both iDMI and spin-mixing conductance increase with the increase in defect density of graphene obtained by varying argon pressure during sputter deposition of Ni80Fe20. This suggests that the observed iDMI originates from defect-induced extrinsic spin-orbit coupling at the interface. The direct observation of iDMI at graphene/ferromagnet interface without perpendicular magnetic anisotropy opens new route in designing thin film heterostructures based on 2-D materials for controlling chiral spin structure such as skyrmions and bubbles, and magnetic domain-wall-based storage and memory devices