Efficient-UCBV: An Almost Optimal Algorithm using Variance Estimates

We propose a novel variant of the UCB algorithm (referred to as Efficient-UCB-Variance (EUCBV)) for minimizing cumulative regret in the stochastic multi-armed bandit (MAB) setting. EUCBV incorporates the arm elimination strategy proposed in UCB-Improved \citep{auer2010ucb}, while taking into account the variance estimates to compute the arms' confidence bounds, similar to UCBV \citep{audibert2009exploration}. Through a theoretical analysis we establish that EUCBV incurs a \emph{gap-dependent} regret bound of {\scriptsize $O\left( \dfrac{K\sigma^2_{\max} \log (T\Delta^2 /K)}{\Delta}\right)$} after $T$ trials, where $\Delta$ is the minimal gap between optimal and sub-optimal arms; the above bound is an improvement over that of existing state-of-the-art UCB algorithms (such as UCB1, UCB-Improved, UCBV, MOSS). Further, EUCBV incurs a \emph{gap-independent} regret bound of {\scriptsize $O\left(\sqrt{KT}\right)$} which is an improvement over that of UCB1, UCBV and UCB-Improved, while being comparable with that of MOSS and OCUCB. Through an extensive numerical study we show that EUCBV significantly outperforms the popular UCB variants (like MOSS, OCUCB, etc.) as well as Thompson sampling and Bayes-UCB algorithms

Vulnerability of bangladesh to cyclones in a changing climate : potential damages and adaptation cost

This paper integrates information on climate change, hydrodynamic models, and geographic overlays to assess the vulnerability of coastal areas in Bangladesh to larger storm surges and sea-level rise by 2050. The approach identifies polders (diked areas), coastal populations, settlements, infrastructure, and economic activity at risk of inundation, and estimates the cost of damage versus the cost of several adaptation measures. A 27-centimeter sea-level rise and 10 percent intensification of wind speed from global warming suggests the vulnerable zone increases in size by 69 percent given a +3-meter inundation depth and by 14 percent given a +1-meter inundation depth. At present, Bangladesh has 123 polders, an early warning and evacuation system, and more than 2,400 emergency shelters to protect coastal inhabitants from tidal waves and storm surges. However, in a changing climate, it is estimated that 59 of the 123 polders would be overtopped during storm surges and another 5,500 cyclone shelters (each with the capacity of 1,600 people) to safeguard the population would be needed. Investments including strengthening polders, foreshore afforestation, additional multi-purpose cyclone shelters, cyclone-resistant private housing, and further strengthening of the early warning and evacuation system would cost more than $2.4 billion with an annual recurrent cost of more than$50 million. However, a conservative damage estimate suggests that the incremental cost of adapting to these climate change related risks by 2050 is small compared with the potential damage inthe absence of adaptation measures.Climate Change Mitigation and Green House Gases,Climate Change Economics,Science of Climate Change,Hazard Risk Management,Global Environment Facility

Antimicrobial Evaluation of Dichloro Chromene Isoxazoles and Isoxazoline Derivatives

In the present study, the synthesized benzopyran isoxazolines and isoxazoles were evaluated for antibacterial activity by Agar well diffusion method against multi drug resistance (MDR) clinical isolates of five bacterial strains.i.e., Staphylococcus sp. (2413), Enterococcus sp. (2449), and Escherichia sp. (2461), Acinetobacter sp. (2457) and Serratia sp (2442). MIC (Minimum inhibitory concentration) and MBC (Minimum bactericidal concentration) of the potent derivatives were calculated and tabulated. A partial structure activity relationship (SAR) was done on the basis of microbial inhibition data. Compounds 3, 6, 8, 9, 11, 14 and 20 were the most promising antibacterial molecule. Compound 3, the precursor of isoxazole / isoxazoline found to be most active antibacterial candidate as well as bactericidal too

Climate proofing infrastructure in Bangladesh : the incremental cost of limiting future inland monsoon flood damage

Two-thirds of Bangladesh is less than 5 meters above sea level, making it one of the most flood prone countries in the world. Severe flooding during a monsoon causes significant damage to crops and property, with severe adverse impacts on rural livelihoods. Future climate change seems likely to increase the destructive power of monsoon floods. This paper examines the potential cost of offsetting increased flooding risk from climate change, based on simulations from a climate model of extreme floods out to 2050. Using the 1998 flood as a benchmark for evaluating additional protection measures, the authors calculate conservatively that necessary capital investments out to 2050 would total US$2,671 million (at 2009 prices) to protect roads and railways, river embankments surrounding agricultural lands, and drainage systems and erosion control measures for major towns. With gradual climate change, however, required investments would be phased. Beyond these capital-intensive investments, improved policies, planning and institutions are essential to ensure that such investments are used correctly and yield the expected benefits. Particular attention is needed to the robustness of benefits from large-scale fixed capital investments. Investments in increased understanding of risk-mitigation options and in economic mobility will have especially high returns.Hazard Risk Management,Transport Economics Policy&Planning,Climate Change Mitigation and Green House Gases,Science of Climate Change,Climate Change Economics

The Mitogen-Activated Protein Kinase (MAPK) Pathway: Role in Immune Evasion by Trypanosomatids

Leishrnania spp. and Trypanosome cruzi are the causative agents of leishmaniasis and Chagas disease, respectively, two neglected tropical diseases that affect about 25 million people worldwide. These parasites belong to the family Trypanosomatidae, and are both obligate intracellular parasites that manipulate host signaling pathways and the innate immune system to establish infection. Mitogen-activated protein kinases (MAPKs) are serine and threonine protein kinases that are highly conserved in eukaryotes, and are involved in signal transduction pathways that modulate physiological and pathophysiological cell responses. This mini-review highlights existing knowledge concerning the mechanisms that Leishmania spp. and T. cruzi have evolved to target the host's MAPK signaling pathways and highjack the immune response, and, in this manner, promote parasite maintenance in the host.CNPq fellowshipFAPEMIG fellowshipEAPEMIGFAPESPUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Biol Gera, Belo Horizonte, MG, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilEAPEMIG: APQ-01674-14FAPESP: 07/50551-2Web of Scienc

Loss and damage livelihood resilience

Climate change Loss and Damage has emerged as a key challenge of the 21st century. This Policy Brief first frames the challenge and then introduces the Resilience Academy, highlighting 5 key insights that both feed the debate and inform action. Finally, it provides 5 recommendations to the Executive Committee of the Warsaw International Mechanism (WIM ExCom) for its 5-year work plan

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum