Institutional effects as determinants of learning outcomes : exploring state variations in Mexico

This paper uses the OECD's Program for International Student Assessment student-level achievement database for Mexico to estimate state education production functions, controlling for student characteristics, family background, home inputs, resources, and institutions. The authors take advantage of the state-level variation and representative sample to analyze the impact of institutional factors such as state accountability systems and the role of teachers'unions in student achievement. They argue that accountability, through increased use of state assessments, will improve learning outcomes. The authors also cast light on the role of teachers'unions, namely their strength through appointments to the school and relations with state governments. The analysis shows the importance of good relations between states and unions. Furthermore, it demonstrates that accountability systems are cost-effective measures for improving outcomes.Tertiary Education,Education For All,Teaching and Learning,Secondary Education,Primary Education

Weyl anomalies and the nature of the gravitational field

The presence of gravity generalizes the notion of scale invariance to Weyl invariance, namely, invariance under local rescalings of the metric. In this work, we have computed the Weyl anomaly for various classically scale or Weyl invariant theories, making particular emphasis on the differences that arise when gravity is taken as a dynamical fluctuation instead of as a non-dynamical background field. We find that the value of the anomaly for the Weyl invariant coupling of scalar fields to gravity is sensitive to the dynamical character of the gravitational field, even when computed in constant curvature backgrounds. We also discuss to what extent those effects are potentially observable.Comment: 37 pages, 1 tabl

Weighing the Vacuum Energy

We discuss the weight of vacuum energy in various contexts. First, we compute the vacuum energy for flat spacetimes of the form $\mathbb{T}^3 \times \mathbb{R}$, where $\mathbb{T}^3$ stands for a general 3-torus. We discover a quite simple relationship between energy at radius $R$ and energy at radius $\frac{l_s^2}{ R}$. Then we consider quantum gravity effects in the vacuum energy of a scalar field in $\mathbb{M}_3 \times S^1$ where $\mathbb{M}_3$ is a general curved spacetime, and the circle $S^1$ refers to a spacelike coordinate. We compute it for General Relativity and generic transverse {\em TDiff} theories. In the particular case of Unimodular Gravity vacuum energy does not gravitate.Comment: 32 pages. Minor correction

Information-driven persistent sensing of a non-cooperative mobile target using UAVs

This paper addresses the persistent sensing problem of moving ground targets of interest using a group of fixed wing UAVs. Especially, we aim to overcome the challenge of physical obscuration in complex mission environments. To this end, the persistent sensing problem is formulated under an optimal control framework, i.e. deploying and managing UAVs in a way maximising the visibility to the non-cooperative target.The main issue with such a persistent sensing problem is that it generally requires the knowledge of future target positions, which is uncertain. To mitigate this issue, a probabilistic map of the future target position is widely utilised. However, most of the probabilistic models use only limited information of the target. This paper proposes an innovative framework that can make the best use of all available information, not only limited information. For the validation of the feasibility, the performance of the proposed framework is tested in a Manhattan-type controlled urban environment. All the simulation tests use the same framework proposed, but utilise different level of information. The simulation results confirm that the performance of the persistent sensing significantly improves, up to 30%, when incorporating all available target information

Septic Pelvic Thrombophlebitis: Diagnosis and Management

Septic pelvic thrombophlebitis (SPT) was initially diagnosed and described in the late 1800's. The entity had a high incidence and mortality during this period of time, and a surgical therapeutic approach was the treatment of choice. Since then, the diagnosis, incidence, and management of the entity evolved. This evolution followed the development of newer diagnostic tools such as computed tomography (CT), magnetic resonance imaging (MRI), and a better understanding of the pathophysiology of the disease. The treatment of SPT has had significant changes as well, from a surgical approach at the end of the 19th century to a medical approach after the 1960's. By using an adequate broad-spectrum antibiotic therapy, mortality has decreased. However, controversy in the management of this entity remains even till today