759 research outputs found
Measurement of with Three-Prong Decays at LHCb
The observable is a probe for Lepton Universality violation, so it is
sensitive to New Physics processes. The current combination of the measurements
of differs from Standard Model predictions with a
significance. A measurement of using
three-prong decays is currently ongoing at LHCb. The statistical
precision of this analysis is 6.7%, i.e. the smallest statistical uncertainty
for a single measurement of this observable. Therefore this measurement will be
important to confirm or disprove the current discrepancy from the theoretical
expectations.Comment: Proceeding of the 52nd Rencontres de Moriond EW 2017, La Thuile,
Italy, March 18-25, 201
CP violation in D0→K+K- and D0→π+π- decays and lepton-flavour universality test with the decay B0→D*-τ+ντ
The LHCb experiment has been designed to exploit the potential of heavy-flavour production in highly energetic pp collisions at the Large Hadron Collider, in order to look for indirect signs of physics beyond the Standard Model of particle physics. This thesis presents two distinct measurements performed using LHCb data. The first is that of the ratio of branching fractions R(D*)=B(B→D*-τ+ντ)/B(B→D*-l+νl), with the τ lepton decaying to final states containing three charged pions, performed using a data sample of pp collisions at the centre-of-mass energies of 7 and 8 Tev, corresponding to 3fb-1 of integrated luminosity. The result is R(D*)=0.291±0.019±0.026±0.013, where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the B(B→D*-π+π-π+) branching fraction, as this decay is used in the analysis as a normalisation for the intermediate measurement of B(B→D*-τ+ντ).
This corresponds to one of the most precise single measurements of R(D*) and to the first performed with the three-prong decay of the Ï„ lepton to date.
The measured value of R(D*) is compatible with previous determinations and with the Standard Model expectation.
The second measurement presented in this thesis is that of the difference between the CP asymmetries in D0→K+K- and D0→π+π- decays, performed using a data sample of pp collisions at the centre-of-mass energy of 13 Tev, corresponding to 6fb-1 of integrated luminosity.
The value of ΔACP=ACP(K+K-)-ACP(π+π-), measured by reconstructing D0 mesons which originate from D*+→D0π+ decays or from B→D0μνX decays, is ΔACP=(-17.1±3.0±1.0)x10-4, where the first uncertainty is statistical and the second systematic. By combining this result with previous LHCb measurements based on Run-1 data, the value of ΔACP results to be ΔACP=(-15.4±2.9)x10-4, which differs from zero by 5.3 standard deviations. This is the first observation of CP violation in the decay of a charm hadron
CBE Clima Tool: a free and open-source web application for climate analysis tailored to sustainable building design
Buildings that are designed specifically to respond to the local climate can
be more comfortable, energy-efficient, and with a lower environmental impact.
However, there are many social, cultural, and economic obstacles that might
prevent the wide adoption of designing climate-adapted buildings. One of the
said obstacles can be removed by enabling practitioners to easily access and
analyse local climate data. The CBE Clima Tool (Clima) is a free and
open-source web application that offers easy access to publicly available
weather files (in EPW format) specifically created for building energy
simulation and design. It provides a series of interactive visualization of the
variables therein contained and several derived ones. It is aimed at students,
educators, and practitioners in the architecture and engineering fields. Since
its launch has been consistently recording over 3000 monthly unique users from
over 70 countries worldwide, both in professional and educational settings.Comment: Submitted to Software
Energy-Constrained Delivery of Goods with Drones Under Varying Wind Conditions
In this paper, we study the feasibility of sending drones to deliver goods
from a depot to a customer by solving what we call the Mission-Feasibility
Problem (MFP). Due to payload constraints, the drone can serve only one
customer at a time. To this end, we propose a novel framework based on
time-dependent cost graphs to properly model the MFP and tackle the delivery
dynamics. When the drone moves in the delivery area, the global wind may change
thereby affecting the drone's energy consumption, which in turn can increase or
decrease. This issue is addressed by designing three algorithms, namely: (i)
compute the route of minimum energy once, at the beginning of the mission, (ii)
dynamically reconsider the most convenient trip towards the destination, and
(iii) dynamically select only the best local choice. We evaluate the
performance of our algorithms on both synthetic and real-world data. The
changes in the drone's energy consumption are reflected by changes in the cost
of the edges of the graphs. The algorithms receive the new costs every time the
drone flies over a new vertex, and they have no full knowledge in advance of
the weights. We compare them in terms of the percentage of missions that are
completed with success (the drone delivers the goods and comes back to the
depot), with delivered (the drone delivers the goods but cannot come back to
the depot), and with failure (the drone neither delivers the goods nor comes
back to the depot).Comment: typo author's nam
Optimal Routing Schedules for Robots Operating in Aisle-Structures
In this paper, we consider the Constant-cost Orienteering Problem (COP) where
a robot, constrained by a limited travel budget, aims at selecting a path with
the largest reward in an aisle-graph. The aisle-graph consists of a set of
loosely connected rows where the robot can change lane only at either end, but
not in the middle. Even when considering this special type of graphs, the
orienteering problem is known to be NP-hard. We optimally solve in polynomial
time two special cases, COP-FR where the robot can only traverse full rows, and
COP-SC where the robot can access the rows only from one side. To solve the
general COP, we then apply our special case algorithms as well as a new
heuristic that suitably combines them. Despite its light computational
complexity and being confined into a very limited class of paths, the optimal
solutions for COP-FR turn out to be competitive even for COP in both real and
synthetic scenarios. Furthermore, our new heuristic for the general case
outperforms state-of-art algorithms, especially for input with highly
unbalanced rewards
Dispatching Point Selection For A Drone-based Delivery System Operating In A Mixed Euclidean–Manhattan Grid
In this paper, we present a drone-based delivery system that assumes to deal with a mixed-area, i.e., two areas, one rural and one urban, placed side-by-side. In the mixed-areas, called EM-grids, the distances are measured with two different metrics, and the shortest path between two destinations concatenates the Euclidean and Manhattan metrics. Due to payload constraints, the drone serves a single customer at a time returning back to the dispatching point (DP) after each delivery to load a new parcel for the next customer. In this paper, we present the 1 -Median Euclidean–Manhattan grid Problem (MEMP) for EM-grids, whose goal is to determine the drone\u27s DP position that minimizes the sum of the distances between all the locations to be served and the point itself. We study the MEMP on two different scenarios, i.e., one in which all the customers in the area need to be served (full-grid) and another one where only a subset of these must be served (partial-grid). For the full-grid scenario we devise optimal and approximation algorithms, while for the partial-grid scenario we devise an optimal algorithm
A Drone-Based Application for Scouting Halyomorpha Halys Bugs in Orchards with Multifunctional Nets
In this work, we consider the problem of using a drone to collect information within orchards in order to scout insect pests, i.e., the stink bug Halyomorpha halys. An orchard can be modeled as an aisle-graph, which is a regular and constrained data structure formed by consecutive aisles where trees are arranged in a straight line. For monitoring the presence of bugs, a drone flies close to the trees and takes videos and/or pictures that will be analyzed offline. As the drone\u27s energy is limited, only a subset of locations in the orchard can be visited with a fully charged battery. Those places that are most likely to be infested should be selected to promptly detect the pest. We implemented the proposed approach on a DJI drone and evaluated its performance in the real-world environment
Population trends of the fan mussel Pinna nobilis from Portofino MPA (Ligurian Sea, Western Mediterranean Sea) before and after a mass mortality event and a catastrophic storm
Two Pinna nobilis populations thriving inside the borders of the Portofino Marine Protected Area (MPA) (Ligurian Sea, western Mediterranean Sea) were monitored before (2012) and after (September 2018) a dire mass mortality event that, since September 2016, spread through the whole Mediterranean Sea. In Portofino MPA, recorded mortality rates reached values of 91.29% and 43.94% in the two populations. The presence of a Haplosporidium protozoan parasite, considered to be the main cause of the mortality episodes, was confirmed from histological evidence: sporocysts and plasmodia were observed in all the tubules of the digestive glands of the collected specimens. Moreover, a catastrophic storm hit the Ligurian coasts at the end of October 2018, causing considerable damages both below and above the surface; a new survey conducted in November 2018 showed the complete annihilation of the two studied populations, as a probable combination of the continued parasite infections and the mechanical impacts caused by the storm. Finally, in June 2020 the sites were monitored again looking for traces of recovery, but no new specimens were recorded, indicating that P. nobilis became virtually absent from the MPA
Radar detection of pedestrian-induced vibrations on Michelangelo’s David
This paper summarizes the results of a two-day dynamic monitoring of Michelangelo's David subject to environmental loads (city traffic and pedestrian loading induced by tourists visiting the Accademia Gallery). The monitoring was carried out by a no-contact technique using an interferometric radar, whose effectiveness in measuring the resonant frequencies of structures and historic monuments has proved over the last years through numerous monitoring activities. Owing to the dynamic behavior of the measurement system (radar and tripod), an accelerometer has been installed on the radar head to filter out the movement component of the measuring instrument from the measurement of the David's displacement. Measurements were carried out in the presence and absence of visitors, to assess their influence on the dynamic behavior of the statue. A numerical model of the statue was employed to evaluate the experimental results
Facies created by the yellow coral Dendrophyllia cornigera (Lamarck, 1816): Origin, substrate preferences and habitat complexity
The yellow coral Dendrophyllia cornigera (Lamarck, 1816) is a NE Atlantic-Mediterranean scleractinian. It is considered a typical hard bottom species, generally reported on outcropping rocks from mesophotic to upper bathyal depths. Several evidences suggest that this species is able to tolerate a broad range of temperatures, which allows it to colonize numerous environments in a wide depth range.
In the present study, we first provided a detailed ecological characterization of the D. cornigera dense aggregation thriving on the Mantice Shoal (NW Ligurian Sea, Mediterranean Sea). Information on substrate type and inclination, average extension and density, colonies size-class frequency distribution and associated fauna are reported. Then, we presented an extensive review of the available information on the ecology of this species, including 142 new ROV records from the Italian coast (40–1820 m). Results indicated that D. cornigera occurs on a wide range of substrates, including soft bottoms and hardgrounds (outcropping rocks, coralligenous rock and dead cold-water coral frameworks), with significant differences in colony density and size among different substrates.
Dendrophyllia cornigera creates three main facies, each characterized by a specific combination of substrate, inclination, depth, and associated fauna. Scattered living colonies, as well as large thanatocoenoses, display a wide geographical and bathymetric distribution. Differently, the facies represented by dense meadows on horizontal soft-bottoms results rare, being reported only from the Mantice Shoal and the Amendolara Bank (Ionian Sea). The radiocarbon age of the thanatocoenoses varies between 400 (Corsica Channel) and 13000 (Vercelli Seamount) years before present.
This study highlights the wide adaptability of D. cornigera in terms of environmental settings, changing the current view on the ecology of this species and providing essential insights for the implementation of international deep-sea habitat classification schemes and conservation measures
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