Duality between imperfect resources and measurements for propagating entanglement in networks

We propose a measurement-based entanglement propagation strategy for networks in which all nodes except two are initially occupied by a suitably chosen single-qubit system and the two nodes share a bipartite noisy entangled state. The connections between the sites are established using unsharp two-qubit measurements. When only a single node performs measurements, we refer to it as a unidirectional protocol while when both parts of the initial entangled states perform measurements, we call it a bidirectional scheme. When the measurement outcome is post-selected, we demonstrate that in the presence of a local amplitude damping channel acting on a single site, entanglement shareability, as measured by the monogamy score, of the resulting state after measurement can be higher for all values of the strength of the noise than that of the scenario without noise. We observe that irrespective of the channel, there exists a range of unsharpness parameter where a higher monogamy score may be obtained starting from the initial nonmaximally entangled states than from the initial maximally entangled state. We report that the effect of noise on the average monogamy score entered from the resource state may be reduced faster with the unidirectional protocol than with the bidirectional one.Comment: 13 pages, 11 figure

Arbitrary Pattern Formation on a Continuous Circle by Oblivious Robot Swarm

In the field of distributed system, Arbitrary Pattern Formation (APF) problem is an extensively studied problem. The purpose of APF is to design an algorithm to move a swarm of robots to a particular position on an environment (discrete or continuous) such that the swarm can form a specific but arbitrary pattern given previously to every robot as an input. In this paper the solvability of the APF problem on a continuous circle has been discussed for a swarm of oblivious and silent robots without chirality under a semi synchronous scheduler. Firstly a class of configurations called \textit{Formable Configuration}($FC$) has been provided which is necessary to solve the APF problem on a continuous circle. Then considering the initial configuration to be an $FC$, an deterministic and distributed algorithm has been provided that solves the APF problem for $n$ robots on a continuous circle of fixed radius within $O(n)$ epochs without collision

Approximation Schemes for Geometric Knapsack for Packing Spheres and Fat Objects

We study the geometric knapsack problem in which we are given a set of $d$-dimensional objects (each with associated profits) and the goal is to find the maximum profit subset that can be packed non-overlappingly into a given $d$-dimensional (unit hypercube) knapsack. Even if $d=2$ and all input objects are disks, this problem is known to be NP-hard [Demaine, Fekete, Lang, 2010]. In this paper, we give polynomial-time $(1+\varepsilon)$-approximation algorithms for the following types of input objects in any constant dimension $d$: - disks and hyperspheres, - a class of fat convex polygons that generalizes regular $k$-gons for $k\ge 5$ (formally, polygons with a constant number of edges, whose lengths are in a bounded range, and in which each angle is strictly larger than $\pi/2$) - arbitrary fat convex objects that are sufficiently small compared to the knapsack. We remark that in our \textsf{PTAS} for disks and hyperspheres, we output the computed set of objects, but for a $O_\varepsilon(1)$ of them we determine their coordinates only up to an exponentially small error. However, it is not clear whether there always exists a $(1+\varepsilon)$-approximate solution that uses only rational coordinates for the disks' centers. We leave this as an open problem which is related to well-studied geometric questions in the realm of circle packing.Comment: 28 pages, 8 figure

A Cytochrome P450 TxtE Model System with Mechanistic and Theoretical Evidence for a Heme Peroxynitrite Active Species

The cytochrome P450 homolog, TxtE, efficiently catalyzes the direct and regioselective aromatic nitration of the indolyl moiety of L-tryptophan to 4-nitro-L-tryptophan, using nitric oxide (NO) and dioxygen (O2) as co-substrates. Pathways for such direct and selective nitration of heteroaromatic motifs present platforms for engineering new nitration biocatalysts for pharmacologically beneficial targets, among a medley of other pivotal industrial applications. Precise mechanistic details concerning this pathway are only weakly understood, albeit a heme iron(III)-peroxynitrite active species has been postulated. To shed light on this unique reaction landscape, we investigated the indole nitration pathway of a series of biomimetic ferric heme superoxide mimics, [(Por)FeIII(O2–•)], in the presence of NO. Therein, our model systems gave rise to three distinct nitroindole products, including 4-nitroindole, the product analogous to that obtained with TxtE. Moreover, 15N and 18O isotope labeling studies, along with meticulously designed control experiments lend credence to a heme peroxynitrite active nitrating agent, drawing close similarities to the tryptophan nitration mechanism of TxtE. All organic and inorganic reaction components have been fully characterized using spectroscopic methods. Theoretical investigation into several mechanistic possibilities deem a unique indolyl radical based reaction pathway as the most energetically favorable, products of which, are in excellent agreement with experimental findings.Scab is a disease situation that causes lesions in root vegetables which drastically reduces their marketability, where potato scab is by far the most economically impactful. Thaxtomin A, which inhibits cellulose biosynthesis[28] is predominantly produced by Streptomyces scabies, and is essentially effected by the condensation of nitrotryptophan and phenylalanine, followed by a hydroxylation step. (Figure 1A).[29-31] The very first step in this particular pathway involves the direct and regioselective nitration of the indolyl moiety of L-tryptophan (L-Trp) to 4-nitro-L-tryptophan (4-NO2-Trp; Figure 1A) using nitric oxide (NO)[32] and dioxygen (O2),[17] which is catalyzed by the aforementioned TxtE P450 enzyme. Indeed, the nitro group of thaxtomin A has been deemed indispensable for its observed virulence against the host. However, the precise mechanistic details surrounding how these primarily monooxygenase enzymes facilitate the high-fidelity insertion of -NO2 groups into various biorelevant organic moieties remain enigmatic to-date.[33] This lack of comprehension in turn severely limits the prospects of corresponding biosynthetic pathways being targeted by prolific bactericides with significant agricultural and health benefits

Ni-sinapic acid nanocomposite in the selective sensing of permanganate ions

A polyphenolic acid assisted synthesis of Ni nano particles for absorption spectrophotometric sensing of MnO4- ions in micro molar range is reported here. The synthesis was carried out using a green approach where sinapic acid acts as a capping agent. The synthesized nano particle was then characterized using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, powder X-ray diffraction analysis, X-ray photoelectron spectroscopy. The particle size is around 5 to 10 nm with the presence of both porosity and nano crystallinity as obtained from the transmission electron microscopic analysis. This nano particle can selectively sense permanganate ions in presence of different co-existing ions with the limit of detection (LOD) 0.413 µM. The sensing mechanism was examined with the isothermal titration calorimetry (ITC) and X-ray photoelectron spectroscopy (XPS). Isothermal titration calorimetric data suggests that the interaction between permanganate and the nano particle is enthalpy driven process with ΔH and ΔG values are −80 kcal/mol and −5.72 kcal/mol respectively. XPS data confirmed the presence of Ni(II) ions in the Ni-SA NPs and the atomic percentage of the same differed in presence of KMnO4. There was no significant interference from the contemporary ions and even in the presence of Mn2+ ion. The method has also been applied for the natural water samples and for vegetable. ∼ 88 to 108 % of the added KMnO4 could be recovered from the tap water sample using our prepared methodology. The limit of detection and the present technique are compared with the previously reported literature and have been found to be comparable, even in solvent-free conditions and using simple instrumentation

The Impact of Weather Change on Honey Bee Populations and Disease

This review provides an overview of the honey bee (Apis mellifera) which is one of the most important pollinators for agriculture and ecosystems, considered a critical yet fragile contributor to world biodiversity and food security among the countless species facing unprecedented challenges due to uneven climate drivers. Scientists are concerned about the impact of climate change on honey bee habitats. This review study looks at the complicated relationship between climate change and honey bees’ health leading to their genetic and behavioural changes. Further, it also mentions how changes in temperature and weather patterns affect foraging, reproduction and colony survival. This study will focus on the different processes that highlight their susceptibility and emphasise the critical need for comprehensive approaches to mitigate the potential consequences through policy implementation. &nbsp

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe