Acceleration of cosmic rays and gamma-ray emission from supernova remnant/molecular cloud associations

The gamma-ray observations of molecular clouds associated with supernova remnants are considered one of the most promising ways to search for a solution of the problem of cosmic ray origin. Here we briefly review the status of the field, with particular emphasis on the theoretical and phenomenological aspects of the problem.Comment: Invited talk at SUGAR201

Dynamic structure factor for 3He in two-dimensions

Recent neutron scattering experiments on 3He films have observed a zero-sound mode, its dispersion relation and its merging with -and possibly emerging from- the particle-hole continuum. Here we address the study of the excitations in the system via quantum Monte Carlo methods: we suggest a practical scheme to calculate imaginary time correlation functions for moderate-size fermionic systems. Combined with an efficient method for analytic continuation, this scheme affords an extremely convincing description of the experimental findings.Comment: 5 pages, 5 figure

Tying Odysseus to the Mast: Evidence from a Commitment Savings Product in the Philippines

We designed a commitment savings product for a Philippine bank and implemented it using a randomized control methodology. The savings product was intended for individuals who want to commit now to restrict access to their savings, and who were sophisticated enough to engage in such a mechanism. We conducted a baseline survey on 1777 existing or former clients of a bank. One month later, we offered the commitment product to a randomly chosen subset of 710 clients; 202 (28.4 percent) accepted the offer and opened the account. In the baseline survey, we asked hypothetical time discounting questions. Women who exhibited a lower discount rate for future relative to current tradeoffs, and hence potentially have a preference for commitment, were indeed significantly more likely to open the commitment savings account. After twelve months, average savings balances increased by 81 percentage points for those clients assigned to the treatment group relative to those assigned to the control group. We conclude that the savings response represents a lasting change in savings, and not merely a short-term response to a new product.Savings, commitment, hyperbolic preferences, microfinance, development economics, program evaluation, field experiment, self-control

Los Nava: Testimonios of three first-generation siblings and their college going decisions

Abstract La familia Nava originates with two hard working immigrant parents that came to the United States seeking educational opportunities for their children. This is the testimony of the three eldest siblings, Arturo, Maria, and Lucero, and their college search and application process. We follow them and the challenges they face as first-generation college students from low-income backgrounds. Using Yosso’s theory of Community Cultural Wealth and Iloh’s Model of College-Going Decisions and Trajectories as the frameworks, one can investigate the ways in which first-generation college students navigate this process and expose real barriers on their paths towards higher education. Resumen La familia Nava se originó con dos padres inmigrantes y trabajadores que llegaron a los Estados Unidos en busca de oportunidades educativas para sus hijos. Este texto cuenta los testimonios de tres hermanos, Arturo, María y Lucero, y sus procesos de solicitud a las universidades como estudiantes de primera generación, de bajos ingresos, y de origen mexicano. Las formas en las cuales los estudiantes universitarios de primera generación navegan este proceso se pueden investigar usando la teoría de la riqueza cultural comunitaria de Yosso y el modelo de decisiones y trayectorias de ir a la universidad de Iloh como marcos teóricos. Con estas historias se exponen las barreras y los desafíos reales que enfrentan los estudiantes de primera generación en su camino hacia la educación universitaria

Non-linear diffusion of cosmic rays escaping from supernova remnants - I. The effect of neutrals

Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs are released and the way in which they propagate still remain open issues. The main difficulty is the high non-linearity of the problem: CRs themselves excite the magnetic turbulence that confines them close to their sources. We solve numerically the coupled differential equations describing the evolution in space and time of the escaping particles and of the waves generated through the CR streaming instability. The warm ionized and warm neutral phases of the interstellar medium are considered. These phases occupy the largest fraction of the disc volume, where most supernovae explode, and are characterised by the significant presence of neutral particles. The friction between those neutrals and ions results in a very effective wave damping mechanism. It is found that streaming instability affects the propagation of CRs even in the presence of ion-neutral friction. The diffusion coefficient can be suppressed by more than a factor of $\sim 2$ over a region of few tens of pc around the remnant. The suppression increases for smaller distances. The propagation of $\approx 10$ GeV particles is affected for several tens of kiloyears after escape, while $\approx 1$ TeV particles are affected for few kiloyears. This might have a great impact on the interpretation of gamma-ray observations of molecular clouds located in the vicinity of supernova remnants.Comment: Revised to match the version published in MNRA

The Importance of Validation in Latine Student Success

Latine students are the fastest growing ethnic group currently in higher education and yet they experience lower undergraduate completion rates than their white peers. In this paper I explore Validation theory, in combination with community cultural wealth and the Bicultural Orientation Model and Influences on Latino Identity, and the ways in which they can be used to support Latine students. Validation is defined as a positive external affirmation to students that positively impacts their own belief to succeed. With the Latine undergraduate student population growing, validation theory can be an important tool to address the issues relevant to students from this demographic

A lock-in Transboundary Water Management Regime: the case of the Rio Grande/Bravo Basin

The study of the Rio Grande/Bravo (RGB) Basin water management demonstrates how the United States (US) and Mexico have consolidated a transboundary water regime based on groundwater sharing. Despite the lack of water management integration and common sustainable practices, both countries have succeeded in sharing groundwater resources in the past, but not for long. The transboundary water regime in RGB Basin is based on fixed groundwater extractions which do not match the ever increasing water demands and current adjustments for human and environmental needs, and the potential future natural conditions for a sustainable river system. The aim of this paper is to discuss that despite the fact that the US – Mexico water regime has given good results in terms of water allocation; the system is imperfect due to a lack of consideration of current and future environmental, economic and socio-political drivers, as well as seeing the system as a whole, promoting a conjunctive use of surface water and groundwater. Findings of this study are based on a qualitative interview study conducted with stakeholders in the RGB Basin and an analysis of historic water demands. Our sample included 54 respondents across the basin, they addressed a multitude of concerns in the context of environmental problems, fragmented water management, and citizen participation. This presentation elaborates on three key questions: (1) How the RGB water allocation regime can last with fixed water demands and without adapting to current changes in natural conditions? (2) What is the impact of this regime in the river ecosystem? (3) Does the RGB Basin water regime reflect a lock in situation that is blocking changes toward new water management practices? If so, how stakeholders can promote changes in the decision-making process? The situation of the RGB water regime can be explained through the concept of long-term predominance which results in a path-dependent process. This process helps to address sustained persistence and processes of institutions leading to a lock-in state. The RGB water regime needs major transformations, specifically in considering environmental, economical, and socio-political variables in groundwater management across the river basin, as well as the conjunctive use of surface and groundwater. A list of recommendations to enhance and optimize current water management regime is presented with a discussion of possibilities of dissolving binational organizational paths