Agri-environmental Regulation on the Back of a Data Envelopment Analysis

A land retirement policy whereby land is taken out of agriculture and converted to natural vegetation or forestry has the potential to reduce environmental damage related to dryland salinity in Western Australia. This paper uses some recent results in the theory of directional distance functions (Chambers and Fare, 2004) to analyse alternative policy designs for a land retirement scheme. The results indicate that a fixed price scheme is inefficient compared with a first-best solution, but performs adequately. A scheme requiring a fixed proportion of area retired by all producers is inefficient. A separating solution, based on mechanism design, gives a small but significant increase in welfare compared to a fixed price scheme.Agri-environmental policy, distance functions, efficiency, mechanism design, Environmental Economics and Policy, Q12,

Formation of terrestrial planets in close binary systems: the case of Alpha Centauri A

At present the possible existence of planets around the stars of a close binary system is still matter of debate. Can planetary bodies form in spite of the strong gravitational perturbations of the companion star? We study in this paper via numerical simulation the last stage of planetary formation, from embryos to terrestrial planets in the Alpha Cen system, the prototype of close binary systems. We find that Earth class planets can grow around Alpha Cen A on a time-scale of 50 Myr. In some of our numerical models the planets form directly in the habitable zone of the star in low eccentric orbits. In one simulation two of the final planets are in a 2:1 mean motion resonance that, however, becomes unstable after 200 Myr. During the formation process some planetary embryos fall into the stars possibly altering their metallicity.Comment: accepted for pubblication in A&A, 13 pages, 9 figure

Developing Professional Vision for Practice: Preservice Teachers using Students' Scientific Ideas in Simulations of Practice.

Learning to teach science is difficult for preservice elementary teachers. It involves adopting the practices and principles valued in the teaching profession. A central challenge novice teachers face is learning to interpret students’ ideas as they construct explanations of phenomena. The particular ways that teachers see and understand instructional interactions has been referred to as professional vision (Goodwin, 1994). This dissertation examined the ways in which a simulation of practice called “Peer Teaching” supported the development of novices’ professional vision in the context of an elementary science methods course. Each novice teacher role-played a “teacher” and taught three science lessons to a team of novices and a teacher educator who acted as “elementary students. ” The central research question in this study was: How do preservice teachers develop professional vision for practice in the context of Peer Teaching feedback discussions? Qualitative data were collected from 16 novice teachers in four Peer Teaching teams. These data included 48 videos of Peer Teaching feedback discussions, Peer Teaching artifacts, and interviews with one novice teacher from each team. The findings of the study suggest that developing professional vision in simulations involves learning to notice and use what is valued in the profession, the professional Discourse. Specifically, my analyses indicated that opportunities for developing professional vision occurred as the novices and the teacher educators (1) established a professional Discourse through tools; (2) approximated the professional Discourse through roles; (3) identified challenges of the professional Discourse; (4) used the professional Discourse to articulate thinking about the challenges; and (5) used the professional Discourse to envision alternatives to the challenges. Novices’ noticing was supported and constrained by the features of the Peer Teaching as located in the interacting contexts of the course and the teacher education program. This was evident in the ways novices expressed a contradiction between two competing objects of developing professional vision: identifying problems of practice and affirming peers’ practice. The concepts of professional Discourse and interacting contexts have implications for the design of teaching simulations to support novices’ development of professional vision.PHDEducational StudiesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/107187/1/mbenedi_1.pd

Expression of CD226 is associated to but not required for NK cell education

AbstractDNAX accessory molecule-1 (DNAM-1, also known as CD226) is an activating receptor expressed on subsets of natural killer (NK) and T cells, interacts with its ligands CD155 or CD112, and has co-varied expression with inhibitory receptors. Since inhibitory receptors control NK-cell activation and are necessary for MHC-I-dependent education, we investigated whether DNAM-1 expression is also involved in NK-cell education. Here we show an MHC-I-dependent correlation between DNAM-1 expression and NK-cell education, and an association between DNAM-1 and NKG2A that occurs even in MHC class I deficient mice. DNAM-1 is expressed early during NK-cell development, precedes the expression of MHC-I-specific inhibitory receptors, and is modulated in an education-dependent fashion. Cd226−/− mice have missing self-responses and NK cells with a normal receptor repertoire. We propose a model in which NK-cell education prevents or delays downregulation of DNAM-1. This molecule endows educated NK cells with enhanced effector functions but is dispensable for education.</jats:p

The architecture of the GJ876 planetary system. Masses and orbital coplanarity for planets b and c

We present a combined analysis of previously published high-precision radial velocities and astrometry for the GJ876 planetary system using a self-consistent model that accounts for the planet-planet interactions. Assuming the three planets so far identified in the system are coplanar, we find that including the astrometry in the analysis does not result in a best-fit inclination significantly different than that found by Rivera and collaborators from analyzing the radial velocities alone. In this unique case, the planet-planet interactions are of such significance that the radial velocity data set is more sensitive to the inclination of the system through the dependence of the interactions on the true masses of the two gas giant planets in the system (planets b and c). The astrometry does allow determination of the absolute orbital inclination (i.e. distinguishing between i and 180-i) and longitude of the ascending node for planet b, which allows us to quantify the mutual inclination angle between its orbit and planet c's orbit when combined with the dynamical considerations. We find that the planets have a mutual inclination of 5.0 +3.9 -2.3 degrees. This result constitutes the first determination of the degree of coplanarity in an exoplanetary system around a normal star. That we find the two planets' orbits are nearly coplanar, like the orbits of the Solar System planets, indicates that the planets likely formed in a circumstellar disk, and that their subsequent dynamical evolution into a 2:1 mean motion resonance only led to excitation of a small mutual inclination. This investigation demonstrates how the degree of coplanarity for other exoplanetary systems could also be established using data obtained from existing facilities.Comment: 9 pages, accepted for publication in A&

Exploiting Mass Spectrometry to Unlock the Mechanism of Nanoparticle-Induced Inflammasome Activation

Nanoparticles (NPs) elicit sterile inflammation, but the underlying signaling pathways are poorly understood. Here, we report that human monocytes are particularly vulnerable to amorphous silica NPs, as evidenced by single-cell-based analysis of peripheral blood mononuclear cells using cytometry by time-of-flight (CyToF), while silane modification of the NPs mitigated their toxicity. Using human THP-1 cells as a model, we observed cellular internalization of silica NPs by nanoscale secondary ion mass spectrometry (nanoSIMS) and this was confirmed by transmission electron microscopy. Lipid droplet accumulation was also noted in the exposed cells. Furthermore, time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed specific changes in plasma membrane lipids, including phosphatidylcholine (PC) in silica NP-exposed cells, and subsequent studies suggested that lysophosphatidylcholine (LPC) acts as a cell autonomous signal for inflammasome activation in the absence of priming with a microbial ligand. Moreover, we found that silica NPs elicited NLRP3 inflammasome activation in monocytes, whereas cell death transpired through a non-apoptotic, lipid peroxidation-dependent mechanism. Together, these data further our understanding of the mechanism of sterile inflammation

"I'm not proud, I'm just gay": lesbian and gay youths' discursive negotiation of otherness

This article outlines the shared identity construction of five gay and lesbian members of an LGBT youth group, situated in a conservative, working-class, Northern English town. It is shown that the young people’s identity work emerges in response to the homophobia and ‘othering’ they have experienced from those in their local community. Through ethnography and discourse analysis, and using theoretical frameworks from interactional sociolinguistics, the strategies that the young people employ to negotiate this othering are explored; they reject certain stereotypes of queer culture (such as Gay Pride or being ‘camp’), and aim to minimise the relevance of their sexuality to their social identity. It is argued this reflects both the influence of neoliberal, ‘homonormative’ ideology, which casts sexuality in the private rather than public domain, and the stigma their sexuality holds in their local community. These findings point to the need to understand identity construction intersectionally

Population genetic structure of Aedes polynesiensis in the Society Islands of French Polynesia: implications for control using a Wolbachia-based autocidal strategy

Abstract Background Aedes polynesiensis is the primary vector of Wuchereria bancrofti in the South Pacific and an important vector of dengue virus. An improved understanding of the mosquito population genetics is needed for insight into the population dynamics and dispersal, which can aid in understanding the epidemiology of disease transmission and control of the vector. In light of the potential release of a Wolbachia infected strain for vector control, our objectives were to investigate the microgeographical and temporal population genetic structure of A. polynesiensis within the Society Islands of French Polynesia, and to compare the genetic background of a laboratory strain intended for release into its population of origin. Methods A panel of eight microsatellite loci were used to genotype A. polynesiensis samples collected in French Polynesia from 2005-2008 and introgressed A. polynesiensis and Aedes riversi laboratory strains. Examination of genetic differentiation was performed using F-statistics, STRUCTURE, and an AMOVA. BAYESASS was used to estimate direction and rates of mosquito movement. Results FST values, AMOVA, and STRUCTURE analyses suggest low levels of intra-island differentiation from multiple collection sites on Tahiti, Raiatea, and Maupiti. Significant pair-wise FST values translate to relatively minor levels of inter-island genetic differentiation between more isolated islands and little differentiation between islands with greater commercial traffic (i.e., Tahiti, Raiatea, and Moorea). STRUCTURE analyses also indicate two population groups across the Society Islands, and the genetic makeup of Wolbachia infected strains intended for release is similar to that of wild-type populations from its island of origin, and unlike that of A. riversi. Conclusions The observed panmictic population on Tahiti, Raiatea, and Moorea is consistent with hypothesized gene flow occurring between islands that have relatively high levels of air and maritime traffic, compared to that of the more isolated Maupiti and Tahaa. Gene flow and potential mosquito movement is discussed in relation to trials of applied autocidal strategies.</p