The UN in the lab

We consider two alternatives to inaction for governments combating terrorism, which we term Defense and Prevention. Defense consists of investing in resources that reduce the impact of an attack, and generates a negative externality to other governments, making their countries a more attractive objective for terrorists. In contrast, Prevention, which consists of investing in resources that reduce the ability of the terrorist organization to mount an attack, creates a positive externality by reducing the overall threat of terrorism for all. This interaction is captured using a simple 3×3 “Nested Prisoner’s Dilemma” game, with a single Nash equilibrium where both countries choose Defense. Due to the structure of this interaction, countries can benefit from coordination of policy choices, and international institutions (such as the UN) can be utilized to facilitate coordination by implementing agreements to share the burden of Prevention. We introduce an institution that implements a burden-sharing policy for Prevention, and investigate experimentally whether subjects coordinate on a cooperative strategy more frequently under different levels of cost sharing. In all treatments, burden sharing leaves the Prisoner’s Dilemma structure and Nash equilibrium of the game unchanged. We compare three levels of burden sharing to a baseline in a between-subjects design, and find that burden sharing generates a non-linear effect on the choice of the efficient Prevention strategy and overall performance. Only an institution supporting a high level of mandatory burden sharing generates a significant improvement in the use of the Prevention strategy

Global Gene Expression Analysis Identifies Age-Related Differences in Knee Joint Transcriptome during the Development of Post-Traumatic Osteoarthritis in Mice.

Aging and injury are two major risk factors for osteoarthritis (OA). Yet, very little is known about how aging and injury interact and contribute to OA pathogenesis. In the present study, we examined age- and injury-related molecular changes in mouse knee joints that could contribute to OA. Using RNA-seq, first we profiled the knee joint transcriptome of 10-week-old, 62-week-old, and 95-week-old mice and found that the expression of several inflammatory-response related genes increased as a result of aging, whereas the expression of several genes involved in cartilage metabolism decreased with age. To determine how aging impacts post-traumatic arthritis (PTOA) development, the right knee joints of 10-week-old and 62-week-old mice were injured using a non-invasive tibial compression injury model and injury-induced structural and molecular changes were assessed. At six-week post-injury, 62-week-old mice displayed significantly more cartilage degeneration and osteophyte formation compared with young mice. Although both age groups elicited similar transcriptional responses to injury, 62-week-old mice had higher activation of inflammatory cytokines than 10-week-old mice, whereas cartilage/bone metabolism genes had higher expression in 10-week-old mice, suggesting that the differential expression of these genes might contribute to the differences in PTOA severity observed between these age groups

Three types of shopping precincts. Three different ways to influence the public sphere of neighborhoods

Indexación: Scopus.Considerando que en la teoría urbana el mercado y los espacios públicos están históricamente vinculados, este artículo analiza un mercado, una galería comercial y un centro comercial (mall). El fin es ilustrar los factores que son determinantes para que en Santiago de Chile estas tipologías de comercio adquieran carácter público y puedan contribuir a la esfera pública de la ciudad, al menos dentro de las limitaciones que se derivan de su condición privada. Hasta ahora el debate ha reflexionado extensivamente sobre estas tres tipologías, sin embargo, existen aún pocos estudios que miran la vida pública que tiene lugar en estas diferentes tipologías de manera paralela, considerando que hoy todas ellas están presentes simultáneamente en la ciudad y se disputan su espacio en ella. Esta investigación describe características físicoespaciales y de administración de estos tres casos para aportar a las políticas públicas y el diseño urbano. Se estudia el comercio en relación a la accesibilidad a nivel metropolitano y en cuanto a los diferentes tipos de comercio, que pretenden atraer un público diverso y promueven el carácter público de los espacios.According to urban theory, commerce and public spaces are historically related to each other. Based on this premise, this paper analyzes a market, a shopping center and a mall. The goal of this research is to identify the key factors that turn these shopping precincts into public spaces and contribute to the public sphere in Santiago, Chile, at least within the context of the limitations associated with their private nature. To date, these three typologies have been the focus of intense debate. However, there are few studies of the public life that takes place in these spaces, especially when considering that they coexist simultaneously in the city, claiming a space within it. This research describes the physical-spatial and administrative characteristics of these three cases in order to contribute to the strengthening of public policies in urban design. Likewise, commerce is studied in relation to accessibility patterns at metropolitan level and the types of markets that aim to attract different users and promote the public nature of these spaces.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-83582018000100089&lng=en&nrm=iso&tlng=e

Effects of the Vibrational Motion of XHY–ON the Post-Photo Detachment Dissociation Dynamics of the XHY Complex (X, Y = Br, I)

We explore the effects of the transition-state vibrational motions on the dynamics of the reaction X + HY →[XHY]‡→XH + Y with X and Y = Br, I. We performed simulations of the dissociation process of the unstable XHY complex using a classical trajectory methodology, combined with London-Eyring-Polanyi-Sato (LEPS) potentials to approximate the interactions among the atoms in XHY. We employed an almost classical sampling scheme on the stable XHY–species to obtain the initial conditions for the trajectories by assuming a vertical transition to the XHY neutral potential energy surface. To study the effects of the vibrations, we considered different sets of initial conditions reflecting specific XHY normal mode excitations. We found an increase in the rotational energies of the product diatoms with an increase in the energy associated to the bending normal modes of XHY. Analysis of the vibrational distributions of the diatoms shows higher most probable vibrational quantum numbers for HBr when compared to HI. For some initial conditions, we also found approximately thermal rotational distributions in the product diatoms

Intermittent maser flare around the high mass young stellar object G353.273+0.641 I: data & overview

We have performed VLBI and single-dish monitoring of 22 GHz H$_{2}$O maser emission from the high mass young stellar object G353.273+0.641 with VERA (VLBI Exploration of Radio Astrometry) and Tomakamai 11-m radio telescope. Two maser flares have been detected, separated almost two years. Frequent VLBI monitoring has revealed that these flare activities have been accompanied by structural change of the prominent shock front traced by H2O maser alignments. We have detected only blue-shifted emissions and all maser features have been distributed within very small area of 200 $\times$ 200 au$^{2}$ in spite of wide velocity range (> 100 km s$^{-1}$). The light curve shows notably intermittent variation and suggests that the H$_{2}$O masers in G353.273+0.641 are excited by episodic radio jet. The time-scale of \sim2 yr and characteristic velocity of \sim500 km s$^{-1}$ also support this interpretation. Two isolated velocity components of C50 (-53 \pm 7 km s$^{-1}$) and C70 (-73 \pm 7 km s$^{-1}$) have shown synchronised linear acceleration of the flux weighted V_{\rmn{LSR}} values (\sim-5 km s$^{-1}$ yr$^{-1}$) during the flare phase. This can be converted to the lower-limit momentum rate of 1.1 \times 10$^{-3}$ M_{\sun} km s$^{-1}$ yr$^{-1}$. Maser properties are quite similar to that of IRAS 20126+4104 especially. This corroborates the previous suggestion that G353.273+0.641 is a candidate of high mass protostellar object. The possible pole-on geometry of disc-jet system can be suitable for direct imaging of the accretion disc in this case.Comment: 13 pages, 5 figures accepted for publication in MNRA

Recent developments in GEANT 4

Fil: Depaola, Gerardo Osvaldo. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.GEANT4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made to the toolkit in order to accommodate the needs of these user communities, and to efficiently exploit the growth of computing power made available by advances in technology. The adaptation of GEANT4 to multithreading, advances in physics, detector modeling and visualization, extensions to the toolkit, including biasing and reverse Monte Carlo, and tools for physics and release validation are discussed here.info:eu-repo/semantics/publishedVersionFil: Depaola, Gerardo Osvaldo. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Física de Partículas y Campo

TMC-1C: an accreting starless core

We have mapped the starless core TMC-1C in a variety of molecular lines with the IRAM 30m telescope. High density tracers show clear signs of self-absorption and sub-sonic infall asymmetries are present in N2H+ (1-0) and DCO+ (2-1) lines. The inward velocity profile in N2H+ (1-0) is extended over a region of about 7,000 AU in radius around the dust continuum peak, which is the most extended ``infalling'' region observed in a starless core with this tracer. The kinetic temperature (~12 K) measured from C17O and C18O suggests that their emission comes from a shell outside the colder interior traced by the mm continuum dust. The C18O (2-1) excitation temperature drops from 12 K to ~10 K away from the center. This is consistent with a volume density drop of the gas traced by the C18O lines, from ~4x10^4 cm^-3 towards the dust peak to ~6x10^3 cm^-3 at a projected distance from the dust peak of 80" (or 11,000 AU). The column density implied by the gas and dust show similar N2H+ and CO depletion factors (f_D < 6). This can be explained with a simple scenario in which: (i) the TMC-1C core is embedded in a relatively dense environment (H2 ~10^4 cm^-3), where CO is mostly in the gas phase and the N2H+ abundance had time to reach equilibrium values; (ii) the surrounding material (rich in CO and N2H+) is accreting onto the dense core nucleus; (iii) TMC-1C is older than 3x10^5 yr, to account for the observed abundance of N2H+ across the core (~10^-10 w.r.t. H2); and (iv) the core nucleus is either much younger (~10^4 yr) or ``undepleted'' material from the surrounding envelope has fallen towards it in the past 10,000 yr.Comment: 29 pages, including 5 tables and 15 figure

Unification of the conditional probability and semiclassical interpretations for the problem of time in quantum theory

We show that the time-dependent Schr\"odinger equation (TDSE) is the phenomenological dynamical law of evolution unraveled in the classical limit from a timeless formulation in terms of probability amplitudes conditioned by the values of suitably chosen internal clock variables, thereby unifying the conditional probability interpretation (CPI) and the semiclassical approach for the problem of time in quantum theory. Our formalism stems from an exact factorization of the Hamiltonian eigenfunction of the clock plus system composite, where the clock and system factors play the role of marginal and conditional probability amplitudes, respectively. Application of the Variation Principle leads to a pair of exact coupled pseudoeigenvalue equations for these amplitudes, whose solution requires an iterative self-consistent procedure. The equation for the conditional amplitude constitutes an effective "equation of motion" for the quantum state of the system with respect to the clock variables. These coupled equations also provide a convenient framework for treating the back-reaction of the system on the clock at various levels of approximation. At the lowest level, when the WKB approximation for the marginal amplitude is appropriate, in the classical limit of the clock variables the TDSE for the system emerges as a matter of course from the conditional equation. In this connection, we provide a discussion of the characteristics required by physical systems to serve as good clocks. This development is seen to be advantageous over the original CPI and semiclassical approach since it maintains the essence of the conventional formalism of quantum mechanics, admits a transparent interpretation, avoids the use of the Born-Oppenheimer approximation, and resolves various objections raised about them.Comment: 10 pages. Typographical errors correcte