Towards a Queueing-Based Framework for In-Network Function Computation

We seek to develop network algorithms for function computation in sensor networks. Specifically, we want dynamic joint aggregation, routing, and scheduling algorithms that have analytically provable performance benefits due to in-network computation as compared to simple data forwarding. To this end, we define a class of functions, the Fully-Multiplexible functions, which includes several functions such as parity, MAX, and k th -order statistics. For such functions we exactly characterize the maximum achievable refresh rate of the network in terms of an underlying graph primitive, the min-mincut. In acyclic wireline networks, we show that the maximum refresh rate is achievable by a simple algorithm that is dynamic, distributed, and only dependent on local information. In the case of wireless networks, we provide a MaxWeight-like algorithm with dynamic flow splitting, which is shown to be throughput-optimal

Coulomb screening in graphene with topological defects

We analyze the screening of an external Coulomb charge in gapless graphene cone, which is taken as a prototype of a topological defect. In the subcritical regime, the induced charge is calculated using both the Green's function and the Friedel sum rule. The dependence of the polarization charge on the Coulomb strength obtained from the Green's function clearly shows the effect of the conical defect and indicates that the critical charge itself depends on the sample topology. Similar analysis using the Friedel sum rule indicates that the two results agree for low values of the Coulomb charge but differ for the higher strengths, especially in the presence of the conical defect. For a given subcritical charge, the transport cross-section has a higher value in the presence of the conical defect. In the supercritical regime we show that the coefficient of the power law tail of polarization charge density can be expressed as a summation of functions which vary log periodically with the distance from the Coulomb impurity. The period of variation depends on the conical defect. In the presence of the conical defect, the Fano resonances begin to appear in the transport cross-section for a lower value of the Coulomb charge. For both sub and supercritical regime we derive the dependence of LDOS on the conical defect. The effects of generalized boundary condition on the physical observables are also discussed.Comment: 14 pages, 11 figure

Universal near-horizon conformal structure and black hole entropy

It is shown that a massless scalar probe reveals a universal near-horizon conformal structure for a wide class of black holes, including the BTZ. The central charge of the corresponding Virasoro algebra contains information about the black hole. With a suitable quantization condition on the central charge, the CFT associated with the black hole in our approach is consistent with the recent observation of Witten, where the dual theory for the BTZ in the AdS/CFT framework has been identified with the construction of Frenkel, Lepowsky and Meurman. This CFT admits the Fischer-Griess monster group as its symmetry. The logarithm of the dimension of a specific representation of the monster group has been identified by Witten as the entropy of the BTZ black hole. Our algebraic approach shows that a wide class of black holes share the same near-horizon conformal structure as that for the BTZ. With a suitable quantization condition, the CFT's for all these black holes in our formalism can be identified with the FLM model, although not through the AdS/CFT correspondence. The corresponding entropy for the BTZ provides a lower bound for the entropy of this entire class of black holes.Comment: References updated, text rearrange

Turbulent flow in graphene

We demonstrate the possibility of a turbulent flow of electrons in graphene in the hydrodynamic region, by calculating the corresponding turbulent probability density function. This is used to calculate the contribution of the turbulent flow to the conductivity within a quantum Boltzmann approach. The dependence of the conductivity on the system parameters arising from the turbulent flow is very different from that due to scattering.Comment: 4 pages, Latex file, Journal versio

Antimicrobial prescribing patterns in surgical inpatient of tertiary care hospital in Eastern India

Background: Antimicrobials form the cornerstone of prescriptions for treating infection. Surgical management cannot be possible without the use of antibiotics. Severity of infection, suspected spectrum of organisms and their sensitivity, co-morbidities of the patient, route of antibiotic administration are the important parameter to consider before selecting antibiotic.Methods: Cross-sectional, hospital based, descriptive study was conducted in the ward of Surgery Department of IQ City Medical college, Durgapur over a period of 1 year. The relevant information was entered into the pretested preformats (containing name, age, sex, diagnosis, ongoing treatment as recorded from patients’ prescription slips or CRFs) and analyzed. Necessary permission was granted by the Institutional Ethical Committee and written informed consent was obtained from the patients prior to collecting their prescription slips/CRF.Results: Commonest cause of hospitalization was cholelithiasis (318 (32.7%)). Antimicrobials were the most commonly prescribed drugs (1626 (31.6%)). Single antibiotic prescribing frequency are similar to two antibiotic prescribing (both 44%). Piperacillin+Tazobactum combination most commonly prescribe antibiotic.Conclusions: Beta lactam antibiotic specifically Piperacillin (ATC class: J01D) were the most commonly prescribed antibiotic agents both before and after surgical procedures

Comparison of intramedullary nailing versus proximal locking plating in the management of closed extra-articular proximal tibial fracture

Background: To compare the outcomes of closed reduction and expert tibial nailing (ETN) versus minimally invasive proximal tibial plating in treating proximal extraarticular tibial fractures.Methods: This study included 30 cases of extraarticular proximal tibial shaft fractures. They were admitted to our department between March 2014 and June 2016 and treated respectively by closed reduction and ETN (group A, n=15) or minimally invasive proximal tibial plating (group B, n=15). To compare the therapeutic effects between two groups, the intraoperative condition, post-operative function, related complications and malalignment were investigated.Results: All the patients were successfully followed up till radiological union. The average union time for group A was 14.2 months and for group B was 16.7 months. 3 patients in group A developed delayed union and was treated with dynamization and ultimately lead to union whereas 1 patient developed non-union in group B. There were 3 cases of superficial infection in group B cured by antibiotics and repeated dressing change. Moreover, group A showed better result in terms of intraoperative blood loss, operation time, postoperative weight bearing time and fracture union time. Functional scores as calculated by the knee rating scale of the hospital for special surgery, 12 (80%) had excellent results in group A compared to 10 (66.66%) in group B which was not statistically significant.Conclusions: Compared with plate and screw fixation, ETN fixation has the advantages of fewer complications, shorter operation time, being less invasive, earlier postoperative rehabilitation and weight bearing, quicker fracture union and better functional recovery, thus being an effective way to treat extra articular proximal tibial fractures