Contribution to the inner tracker design and penguin sensitivity studies for the measurement of sin 2ß in LHCb

LHCb is one of the four large experiments hosted at the Large Hadron Collider (LHC) at CERN in Geneva. It will start taking data in September 2008, and will then operate for several years. It consists of a single-arm forward spectrometer dedicated to precise measurements of CP violation and rare decays in the B sector, with the aim of testing the Standard Model and possibly of discovering the first signatures of New Physics. Building such a large experiment as LHCb is a challenge, and many contributions are needed. The Lausanne lab is responsible for the design and the production of the Silicon Inner Tracker (IT) of LHCb. This detector is made of Silicon sensors which need to be cooled to avoid thermal runaway. We present here a contribution to the design of this sub-detector and a description of the production steps. In particular, a study of the cooling of the Inner Tracker is described. It is shown that the cooling abilities of the IT can avoid thermal runaway. CP violation in B meson decays was first observed in the measurement of the so-called "golden channel", in which a Bd0 meson decays into a J/ψ and a Κs0 . The time-dependent CP asymmetry in Bd0 → J/ψΚs0 allows to measure the angle β of the (d, b) unitary triangle. This parameter is now known with 4% accuracy at B factories. However, this determination of sin 2β is made under the assumption that there is only a single amplitude present in this decay : this means that penguin diagrams which might be present have been neglected. In 1999, Robert Fleischer [29] proposed a theoretical method to access those penguin diagrams in the Bd0 → J/ψΚs0 decay, using the Bs0→ J/ψΚs0 channel. This method relies on U-Spin symmetry and also allows to determine the γ angle of the (d, b) unitary triangle. We have developed a selection method for the Bd0 → J/ψΚs0 channel in order to strongly suppress the background and to allow the separation of the Bs0 and Bd0 peaks. We obtained mass resolution of 8 MeV/c2 and a B/S ratio for the channel Bd0 → J/ψΚs0 estimated to belong to [0, 0.039] at 90% confidence level in a ±2σ mass window around the Bd0 mass, after the first level of trigger (L0). For the channel Bs0 → J/ψΚs0 , the B/S ratio is calculated from the result for Bd0 → J/ψΚs0 assuming known branching fractions. It lies in the interval [0, 3.33] at 90% CL. The annual yield is expected to be around 300 events for an integrated luminosity of 2 fb-1. We have simulated with fast Monte Carlo the Bs0 → J/ψΚs0 signal using the parametrization proposed in [29] and taking as input the results of selection obtained for Bd0 → J/ψΚs0 . The simulation has been repeated several times for different integrated luminosities and B/S ratios. We conclude that after 5 years of normal running, LHCb will be able to determine the penguin contribution in the Bd0 → J/ψΚs0 decay with a sensitivity of (0.172 ± 0.004) using this method based on U-spin symmetry

Achieving Food System Resilience Requires Challenging Dominant Land Property Regimes

Although evidence continues to indicate an urgent need to transition food systems away from industrialized monocultures and toward agroecological production, there is little sign of significant policy commitment toward food system transformation in global North geographies. The authors, a consortium of researchers studying the land-food nexus in global North geographies, argue that a key lock-in explaining the lack of reform arises from how most food system interventions work through dominant logics of property to achieve their goals of agroecological production. Doing so fails to recognize how land tenure systems, codified by law and performed by society, construct agricultural land use outcomes. In this perspective, the authors argue that achieving food system “resilience” requires urgent attention to the underlying property norms that drive land access regimes, especially where norms of property appear hegemonic. This paper first reviews research from political ecology, critical property law, and human geography to show how entrenched property relations in the global North frustrate the advancement of alternative models like food sovereignty and agroecology, and work to mediate acceptable forms of “sustainable agriculture.” Drawing on emerging cases of land tenure reform from the authors’ collective experience working in Scotland, France, Australia, Canada, and Japan, we next observe how contesting dominant logics of property creates space to forge deep and equitable food system transformation. Equally, these cases demonstrate how powerful actors in the food system attempt to leverage legal and cultural norms of property to legitimize their control over the resources that drive agricultural production. Our formulation suggests that visions for food system “resilience” must embrace the reform of property relations as much as it does diversified farming practices. This work calls for a joint cultural and legal reimagination of our relation to land in places where property functions as an epistemic and apex entitlement

Achieving food system resilience requires challenging dominant land property regimes

International audienceAlthough evidence continues to indicate an urgent need to transition food systems away from industrialized monocultures and toward agroecological production, there is little sign of significant policy commitment toward food system transformation in global North geographies. The authors, a consortium of researchers studying the land-food nexus in global North geographies, argue that a key lock-in explaining the lack of reform arises from how most food system interventions work through dominant logics of property to achieve their goals of agroecological production. Doing so fails to recognize how land tenure systems, codified by law and performed by society, construct agricultural land use outcomes. In this perspective, the authors argue that achieving food system “resilience” requires urgent attention to the underlying property norms that drive land access regimes, especially where norms of property appear hegemonic. This paper first reviews research from political ecology, critical property law, and human geography to show how entrenched property relations in the global North frustrate the advancement of alternative models like food sovereignty and agroecology, and work to mediate acceptable forms of “sustainable agriculture.” Drawing on emerging cases of land tenure reform from the authors' collective experience working in Scotland, France, Australia, Canada, and Japan, we next observe how contesting dominant logics of property creates space to forge deep and equitable food system transformation. Equally, these cases demonstrate how powerful actors in the food system attempt to leverage legal and cultural norms of property to legitimize their control over the resources that drive agricultural production. Our formulation suggests that visions for food system “resilience” must embrace the reform of property relations as much as it does diversified farming practices. This work calls for a joint cultural and legal reimagination of our relation to land in places where property functions as an epistemic and apex entitlement

Atom probe tomographic study of L10 martensite in a Pt-modified NiCoCrAlYTa bond coating

The L10 martensite formed in a Pt-modified NiCoCrAlYTa bond coating has been investigated by atom probe tomography. It was found that obvious segregation of Co and Cr occurred in the micro-twins zone inside the martensite lath. Based upon the compositional analysis, it is known that Pt destabilizes the β phase and Co and Cr act as β stabilizers with respect to the β→L10 martensitic transformation. In addition, some α-Cr particles precipitated inside the martensite lath

Th1 Disabled Function in Response to TLR4 Stimulation of Monocyte-Derived DC from Patients Chronically-Infected by Hepatitis C Virus

Background: Lack of protective antibodies and inefficient cytotoxic responses are characteristics of chronic hepatitis C infection. A defect in dendritic cell (DC) function has thus been suspected, but this remains a controversial issue. Methods and Findings: Here we show that monocyte-derived DC (MoDC) from chronically-infected patients can mature in response to TLR1/2, TLR2/6 or TLR3 ligands. In contrast, when stimulated with the TLR4 ligand LPS, MoDC from patients show a profound defect in inducing IFNc secretion by allogeneic T cells. This defect is not due to defective phenotypic maturation or to the presence of HCV-RNA in DC or monocytes but is correlated to reduced IL-12 secretion by DC. Restoration of DC ability to stimulate IFNc secretion can be obtained by blocking MEK activation in DC, indicating that MEK/ ERK pathway is involved in the Th1 defect of MoDC. Monocytes from HCV patients present increased spontaneous secretion of cytokines and chemokines, especially MIP-1b. Addition of MIP-1b on healthy monocytes during differentiation results in DC that have Th1 defect characteristic of MoDC from HCV patients, suggesting that MIP-1b secretion by HCV monocytes participates in the Th1 defect of DC. Conclusions: Our data indicate that monocytes from HCV patients are activated in vivo. This interferes with their differentiation into DC, leading to deficient TLR4 signaling in these cells that are enable to induce a Th1 response. Thi

Favoriser l’insertion professionnelle et l’accès à l’emploi

Cherchant à adapter leurs services à l’actualité sociale et aux besoins réels de leur public, de plus en plus de bibliothèques se préoccupent d’offrir des services orientés vers l’insertion professionnelle et la recherche d’emploi. Qu’elle soit universitaire ou publique, la bibliothèque constitue une ressource essentielle de la formation tout au long de la vie, élément primordial à l’adaptation permanente au monde du travail. Cet ouvrage aborde cette nouvelle problématique pour les établissements sous trois angles différents, selon les besoins des publics : travailler, se former, entreprendre. Les conditions d’accueil des publics concernés, l’adaptation de l’offre suivant la dimension de la bibliothèque, la constitution des collections spécialisées dans ce domaine, la qualité des propositions en matière d’autoformation, les atouts des différents partenariats dans le domaine de la recherche d’emploi, tels sont les éléments traités ici pour favoriser le succès de la mise en place et du développement d’une offre propre à élargir avec efficacité les champs d’intervention des bibliothèques aujourd’hui. Coordonné par Georges Perrin, inspecteur général honoraire des bibliothèques, ce volume collectif réunit des professionnels spécialisés dans le domaine éducatif, social et culturel