Peer-to-Peer Network: Kantian Cooperation Discourage Free Riding

The problem of how to achieve cooperation among rational peers in order to discourage free riding is one that has received a lot of attention in peer-to-peer computing and is still an important one. The field of game theory is applied to the task of finding solutions that will encourage cooperation while discouraging free riding. The cooperative conduct of peers is typically portrayed as a traditional version of the game known as the "Prisoners' Dilemma." It is common knowledge that if two peers engage in a situation known as the Prisoner's Dilemma more than once, collaboration can be achieved through the use of punishment. Nevertheless, this is not the case when there is only one interaction between peers. This short article demonstrates that Kantian peers prefer to cooperate and attain social welfare even when they interacted only once. This, dissuade peers from freeriding.Comment: 1

The Distance and Median Problems in the Single-Cut-Or-Join Model with Single-Gene Duplications

Background. In the field of genome rearrangement algorithms, models accounting for gene duplication lead often to hard problems. For example, while computing the pairwise distance is tractable in most duplication-free models, the problem is NP-complete for most extensions of these models accounting for duplicated genes. Moreover, problems involving more than two genomes, such as the genome median and the Small Parsimony problem, are intractable for most duplication-free models, with some exceptions, for example the Single-Cut-or-Join (SCJ) model. Results. We introduce a variant of the SCJ distance that accounts for duplicated genes, in the context of directed evolution from an ancestral genome to a descendant genome where orthology relations between ancestral genes and their descendant are known. Our model includes two duplication mechanisms: single-gene tandem duplication and the creation of single-gene circular chromosomes. We prove that in this model, computing the directed distance and a parsimonious evolutionary scenario in terms of SCJ and single-gene duplication events can be done in linear time. We also show that the directed median problem is tractable for this distance, while the rooted median problem, where we assume that one of the given genomes is ancestral to the median, is NP-complete. We also describe an Integer Linear Program for solving this problem. We evaluate the directed distance and rooted median algorithms on simulated data. Conclusion. Our results provide a simple genome rearrangement model, extending the SCJ model to account for single-gene duplications, for which we prove a mix of tractability and hardness results. For the NP-complete rooted median problem, we design a simple Integer Linear Program. Our publicly available implementation of these algorithms for the directed distance and median problems allow to solve efficiently these problems on large instances

The Rooted SCJ Median with Single Gene Duplications

The median problem is a classical problem in genome rearrangements. It aims to compute a gene order that minimizes the sum of the genomic distances to  k>=3  given gene orders. This problem is intractable except in the related Single-Cut-or-Join and breakpoint rearrangement models. Here we consider the rooted median problem, where we assume one of the given genomes to be ancestral to the median, which is itself ancestral to the other genomes. We show that in the Single-Cut-or-Join model with single gene duplications, the rooted median problem is NP-hard. We also describe an Integer Linear Program for solving this problem, which we apply to simulated data, showing high accuracy of the reconstructed medians

Higher excitations of ω\omega and ϕ\phi in dilepton spectra

We consider lepton pair production via two-hadron annihilation through various isoscalar vector mesons within hot, baryon-free matter. This is tantamount to constructing effective form factors which we model using a vector-meson-dominance approach and compare with experiment. In particular, we consider the reactions $\pi\rho\to e^+e^-$ and $\bar K K^{*}(892)$ + c.c. $\to e^+e^-$. We find that $\omega(1390)$ and $\phi(1680)$ are visible in the mass spectrum for the thermal production rate above the $\pi^{+}\pi^{-} \to e^+e^-$ tail and even above the $\pi a_{1}\to e^+e^-$ results---both of which were considered important in their respective mass regions.Comment: RevTeX, 9 pages, 6 (uuencoded) figures; to appear in Phys. Rev

Cortical venous thrombosis – a rare complication of tuberculous meningitis

Occlusion of the central veins and sinuses occurs owing to thrombus, thrombophlebitis, or tumours. Cerebral venous thrombosis (CVT) is less frequent than arterial thrombosis, but can produce a cascade of sequelae and may be fatal. The usual predisposing factors for CVT include infections, pregnancy and puerperium, hypercoagulable states, etc. Many infectious causes are related to CVT, but a review of literature showed only few cases related to tuberculosis. Vascular changes consisting of arterial narrowing with or without occlusion are frequently seen at autopsy in cases of tuberculous meningitis. We report one such case of tuberculous meningitis where the patient developed cortical venous thrombosis after 5 days of illness. She was treated empirically, initially, till confirmation of the diagnosis and later was put on antitubercular drugs along with prednisolone therapy and anticoagulation, which led to complete recovery. Thus, if treated aggressively and in time, tuberculous meningitis and its complications are completely curable. Keywords: Tuberculous meningitis; Cortical venous thrombosis; Magnetic resonance venogram; Rare complication of TBMInternet Journal of Medical Update. 2013 January;8(1):31-3

Radial-Electric-Field Piezoelectric Diaphragm Pumps

In a recently invented class of piezoelectric diaphragm pumps, the electrode patterns on the piezoelectric diaphragms are configured so that the electric fields in the diaphragms have symmetrical radial (along-the-surface) components in addition to through-the-thickness components. Previously, it was accepted in the piezoelectric-transducer art that in order to produce the out-of-plane bending displacement of a diaphragm needed for pumping, one must make the electric field asymmetrical through the thickness, typically by means of electrodes placed on only one side of the piezoelectric material. In the present invention, electrodes are placed on both sides and patterned so as to produce substantial radial as well as through-the-thickness components. Moreover, unlike in the prior art, the electric field can be symmetrical through the thickness. Tests have shown in a given diaphragm that an electrode configuration according to this invention produces more displacement than does a conventional one-sided electrode pattern. The invention admits of numerous variations characterized by various degrees of complexity. Figure 1 is a simplified depiction of a basic version. As in other piezoelectric diaphragm pumps of similar basic design, the prime mover is a piezoelectric diaphragm. Application of a suitable voltage to the electrodes on the diaphragm causes it to undergo out-of-plane bending. The bending displacement pushes a fluid out of, or pulls the fluid into, a chamber bounded partly by the diaphragm. Also as in other diaphragm pumps in general, check valves ensure that the fluid flows only in through one port and only out through another port

Snake Bite Complicated By Bacterial Meningitis

Background: Neurotoxic snake bite envenomation is a common life threatening medical emergency in India, especially in the rural areas. Case Presentation: We report a case of a neurotoxic snake envenomation presenting with abdominal pain and neuromuscular paralysis, which developed bacterial meningitis during her stay in the hospital. Possibly, secondary to the snake bite, a very rare incidence. Conclusion: Our case is a step towards the direction pointing to the rare possibility of bacterial meningitis complicating snake bites which needs further research