71 research outputs found
Certainty Closure: Reliable Constraint Reasoning with Incomplete or Erroneous Data
Constraint Programming (CP) has proved an effective paradigm to model and
solve difficult combinatorial satisfaction and optimisation problems from
disparate domains. Many such problems arising from the commercial world are
permeated by data uncertainty. Existing CP approaches that accommodate
uncertainty are less suited to uncertainty arising due to incomplete and
erroneous data, because they do not build reliable models and solutions
guaranteed to address the user's genuine problem as she perceives it. Other
fields such as reliable computation offer combinations of models and associated
methods to handle these types of uncertain data, but lack an expressive
framework characterising the resolution methodology independently of the model.
We present a unifying framework that extends the CP formalism in both model
and solutions, to tackle ill-defined combinatorial problems with incomplete or
erroneous data. The certainty closure framework brings together modelling and
solving methodologies from different fields into the CP paradigm to provide
reliable and efficient approches for uncertain constraint problems. We
demonstrate the applicability of the framework on a case study in network
diagnosis. We define resolution forms that give generic templates, and their
associated operational semantics, to derive practical solution methods for
reliable solutions.Comment: Revised versio
Grasp It Loudly! Supporting Actions with Semantically Congruent Spoken Action Words
Evidence for cross-talk between motor and language brain structures has accumulated over the past several years. However, while a significant amount of research has focused on the interaction between language perception and action, little attention has been paid to the potential impact of language production on overt motor behaviour
APOBEC3A Is a Specific Inhibitor of the Early Phases of HIV-1 Infection in Myeloid Cells
Myeloid cells play numerous roles in HIV-1 pathogenesis serving as a vehicle for viral spread and as a viral reservoir. Yet, cells of this lineage generally resist HIV-1 infection when compared to cells of other lineages, a phenomenon particularly acute during the early phases of infection. Here, we explore the role of APOBEC3A on these steps. APOBEC3A is a member of the APOBEC3 family that is highly expressed in myeloid cells, but so far lacks a known antiviral effect against retroviruses. Using ectopic expression of APOBEC3A in established cell lines and specific silencing in primary macrophages and dendritic cells, we demonstrate that the pool of APOBEC3A in target cells inhibits the early phases of HIV-1 infection and the spread of replication-competent R5-tropic HIV-1, specifically in cells of myeloid origins. In these cells, APOBEC3A affects the amount of vDNA synthesized over the course of infection. The susceptibility to the antiviral effect of APOBEC3A is conserved among primate lentiviruses, although the viral protein Vpx coded by members of the SIVSM/HIV-2 lineage provides partial protection from APOBEC3A during infection. Our results indicate that APOBEC3A is a previously unrecognized antiviral factor that targets primate lentiviruses specifically in myeloid cells and that acts during the early phases of infection directly in target cells. The findings presented here open up new venues on the role of APOBEC3A during HIV infection and pathogenesis, on the role of the cellular context in the regulation of the antiviral activities of members of the APOBEC3 family and more generally on the natural functions of APOBEC3A
Pushing the high count rate limits of scintillation detectors for challenging neutron-capture experiments
One of the critical aspects for the accurate determination of neutron capture
cross sections when combining time-of-flight and total energy detector
techniques is the characterization and control of systematic uncertainties
associated to the measuring devices. In this work we explore the most
conspicuous effects associated to harsh count rate conditions: dead-time and
pile-up effects. Both effects, when not properly treated, can lead to large
systematic uncertainties and bias in the determination of neutron cross
sections. In the majority of neutron capture measurements carried out at the
CERN n\_TOF facility, the detectors of choice are the CD
liquid-based either in form of large-volume cells or recently commissioned sTED
detector array, consisting of much smaller-volume modules. To account for the
aforementioned effects, we introduce a Monte Carlo model for these detectors
mimicking harsh count rate conditions similar to those happening at the CERN
n\_TOF 20~m fligth path vertical measuring station. The model parameters are
extracted by comparison with the experimental data taken at the same facility
during 2022 experimental campaign. We propose a novel methodology to consider
both, dead-time and pile-up effects simultaneously for these fast detectors and
check the applicability to experimental data from Au(,),
including the saturated 4.9~eV resonance which is an important component of
normalization for neutron cross section measurements
Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF
This article presents a few selected developments and future ideas related to the measurement of (n,Îł) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with Îł-ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area
Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF
This article presents a few selected developments and future ideas related to the measurement of (n,Îł) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with Îł-ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area
Analyse des pratiques de gestion de l'eau d'irrigation dans des exploitations des hauts de l'Ouest à la Réunion en vue de la création d'un outil d'aide à la décision
Dans les hauts de l'Ouest de la Réunion, la distribution hétérogène des pluies et leurs intensités imposent un stockage d'eau pendant la saison humide, en vue de son utilisation pendant la saison sèche. A cet effet, des retenues collinaires individuelles ou collectives ont été construites. La gestion stratégique de cette offre en eau limitée en volume est problématique. La démarche engagée utilise la méthodologie d'analyse des pratiques. Cette méthode a pu être appliquée grâce à deux outils méthodologiques : le cadre de représentation et les modèles d'actions des agriculteurs, qui ont permis d'analyser et de comparer les pratiques de gestion de l'eau d'irrigation de l'échantillon. L'analyse comparative de cette diversité a permis de faire émerger différentes stratégies basées sur une relation entre l'offre et la demande en eau d'irrigation. Les simulations de l'évolution de l'offre et de la demande en eau d'irrigation ont été élaborées en vue de poser les bases de la création d'un outil d'aide à la décision. Si la validation des simulations peut être effective, cet outil correspond aux attentes des différents acteurs. Mais elle ne doit être employée de façon unique, il faut développer une nouvelle fonction de conseil qui permettra d'utiliser les simulation
La gestion de l'eau d'irrigation en conditions de ressource limitée (retenues collinaires). Analyse des pratiques et proposition d'outils d'aide à la décision pour les exploitations des Hauts de la Réunion
L'étude s'intéresse à la diversité des situations de gestion de l'eau d'irrigation de retenues collinaires et à la création d'une fonction de conseil d'aide à la gestion de cette eau. Les produits de cette étude peuvent être regroupés en quatre volets : -en premier lieu un cadre de représentation de la gestion de l'eau sur l'exploitation; -un ensemble de références sur les pratiques et les stratégies des agriculteurs en matière d'irrigation; -puis, un outil d'aide à la décision automatisé, permettant de simuler l'évolution de l'équilibre entre l'offre et la demande en eau d'irrigation; -enfin, la proposition de quelques outils adaptés aux différentes situations décrites, visant au pilotage sécurisé et autonome de l'irrigation par les producteurs eux-mêmes. Après une présentation de la zone d'étude et de la méthodologie utilisée, l'analyse s'articule autour des points suivants : l'analyse des contextes d'action d'un panel d'agriculteurs en comparant les situations d'offres et de demandes en eau entre elles, l'étude du mode de gestion de l'eau d'irrigation, la simulation de l'évolution entre l'offre et le demande en ea
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