Using Experimental Economics to Measure the Effects of a Natural Educational Experiment on Altruism

Economic research examining how educational intervention programs affect primary and secondary schooling focuses largely on test scores although the interventions can affect many other outcomes. This paper examines how an educational intervention, a voucher program, affected students' altruism. The voucher program used a lottery to allocate scholarships among low-income applicant families with children in K-8th grade. By exploiting the lottery to identify the voucher effects, and using experimental economic methods, we measure the effects of the intervention on children's altruism. We also measure the voucher program's effects on parents' altruism and several academic outcomes including test scores. We find that the educational intervention positively affects students' altruism towards charitable organizations but not towards their peers. We fail to find statistically significant effects of the vouchers on parents' altruism or test scores.

The Prospect of Responsive Spacecraft Using Aeroassisted, Trans-Atmospheric Maneuvers

Comprised of exo- and trans-atmospheric trajectory segments, atmospheric re-entry represents a complex dynamical event which traditionally signals the mission end-of-life for low-Earth orbit spacecraft. Transcending this paradigm, atmospheric re-entry can be employed as a means of operational maneuver whereby aerodynamic forces can be exploited to create an aeroassisted maneuver. Utilizing a notional trans-atmospheric, lifting re-entry vehicle with L/D =6, the first phase of research demonstrates the terrestrial reachability potential for skip entry aeroassisted maneuvers. By overflying a geographically diverse set of ground targets, comparative analysis indicates a significant savings in delta V expenditure for skip entry compared with exo-atmospheric maneuvers. In the second phase, the Design of Experiments method of orthogonal arrays provides optimal vehicle and skip entry trajectory designs by employing main effects and Pareto front analysis. Depending on re-circularization altitude, the coupled optimal design can achieve an inclination change of 19.91° with 50-85% less delta V than a simple plane change. Finally, the third phase introduces the descent-boost aeroassisted maneuver as an alternative to combined Hohmann and bi-elliptic transfers in order to perform LEO injection. Compared with bi-elliptic transfers, simulations demonstrate that a lifting re-entry vehicle performing a descent-boost maneuver requires 6-12% less for injection into orbits lower than 650 km. In addition, the third phase also introduces the Maneuver Performance Number as a dimensionless means of comparative maneuver effectiveness analysis

Spacecraft Demand Tasking and Skip Entry Responsive Maneuvers

The purpose of this research was to parametrically investigate the viability of skip entry maneuvers as an alternative to vacuum-only maneuvers, and to identify whether skip entry maneuvers can extend spacecraft mission lifetime by limiting propellant expenditure through the exploitation of the aerodynamic interaction between the upper atmosphere and an example entry vehicle and remote-sensing orbital platform. Employing the X-37B Orbital Test Vehicle (OTV) and a notional satellite design as the example entry vehicles, the entry profile dynamics of a skip entry maneuver were characterized with varying trajectory initial conditions such as entry altitude, entry flight-path angle, and vehicle aerodynamics. In addition, the requirements of skip entry maneuvers were characterized, specifically the required to complete one or more successive skip entry trajectories as well as to execute a desired change in orbit inclination angle

The Potentiality of Space Enterprise Force Reconstitution: Nationalizing Civilian Satellites during Kinetic Conflicts

This article will discuss the possibility of employing a policy of civilian satellite nationalization during a space war as a means of US Space Enterprise force re- constitution to ensure continued access to space capabilities necessary for the execution of the national strategy, as well as deterring potential adversaries from initiating counterspace hostilities. In terms of structure, the authors will examine the thesis by answering these questions. First, what historical precedent exists for the rapid military acquisition of civilian assets via nationalization? Second (given the unique nature of space as an operational environment), can that historical precedent be applied to space acquisitions? And, finally, could the nationalization of civilian space assets be used as a deterrent against potential adversaries? This article will answer these questions by utilizing a combination of historical investigation, space environment analysis, and scenario-­driven deterrence theory

An Argument against Satellite Resiliency: Simplicity in the Face of Modern Satellite Design

The US Air Force and the wider US government rely heavily on space-based capabilities in various orbital regimes to project national security and sovereignty. However, these capabilities are enabled by the design, launch, and operation of satellites produced with a design methodology that favors large, monolithic, and technologically exquisite space systems. Despite the ability for these satellites to provide enduring and resilient capabilities, they suffer from a woefully long acquisition process that debilitates any prospect of rapid satellite reconstitution in the event of a space war

Estimación de edades arqueológicas usando la hidratación de obsidianas: dos fuentes de los andes meridionales

Obsidian is abundant in archaeological sites throughout Mendoza Province, Argentina but no obsidian hydration rates exist to date these assemblages. Direct dating of obsidian artifacts is particularly important in west-central Argentina because the surface record is extensive but well-defined time marker artifacts are lacking. The costs of non-optical hydration dating techniques currently preclude their regular use in the region, however. We present and evaluate 12 models for age estimation based on optical hydration rim measurements for the two most commonly used obsidian types in the region (Las Cargas and Laguna del Maule). Age estimation equations are derived for each source using observed hydration rim-radiocarbon date pairs, and parameterized by variables known to influence obsidian hydration in experimental settings. The equations advanced here are currently best at predicting the known ages of artifacts independently dated by radiocarbon, and can be cautiously used to estimate the ages of obsidian artifacts.Las obsidianas son abundantes en los sitios arqueológicos de la provincia de Mendoza (Argentina). Sin embargo, hasta el momento no existen estimaciones para las tasas de hidratación de estas rocas que puedan utilizarse para fechar esos conjuntos líticos. La realización de fechados directos sobre artefactos de obsidiana resulta particularmente importante para esta región, dado que existe un vasto registro arqueológico de superficie –compuesto principalmente por artefactos líticos– y solo se cuenta con tipos morfológicos cronológicamente sensibles para el Holoceno Tardío. Aquí se presentan y evalúan 12 modelos para estimar las edades de los artefactos de obsidiana basados en la medición óptica de los anillos de hidratación. Específicamente estos modelos fueron desarrollados para las dos obsidianas más comunes en los contextos arqueológicos de la región, procedentes de las fuentes de Las Cargas y Laguna del Maule. Las edades estimadas son derivadas para cada fuente a partir de pares de medición del espesor de la corteza de hidratación-fechado radiocarbono, y calibradas con variables cuya influencia sobre la hidratación ha sido establecida experimentalmente. Las ecuaciones que presentamos son actualmente las que mejor predicen las edades conocidas de artefactos que han sido fechados independientemente por radiocarbono y, por lo tanto, pueden utilizarse con cautela para estimar la antigüedad de los artefactos de obsidiana procedentes de la región.Fil: Garvey, Raven. University of Michigan; Estados UnidosFil: Carpenter, Tim. Archaeometrics; Estados UnidosFil: Gil, Adolfo Fabian. Universidad Nacional de Cuyo. Facultad de Filosofía y Letras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla; ArgentinaFil: Neme, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla; ArgentinaFil: Bettinger, Robert. University of California at Davis; Estados Unido

Cultural Innovations and Demographic Change

Demography plays a large role in cultural evolution through its effects on the effective rate of innovation. If we assume that useful inventions are rare, then small isolated societies will have low rates of invention. In small populations, complex technology will tend to be lost as a result of random loss or incomplete transmission (the Tasmanian effect). Large populations have more inventors and are more resistant to loss by chance. If human populations can grow freely, then a population-technology-population positive feedback should occur such that human societies reach a stable growth path on which the rate of growth of technology is limited by the rate of invention. This scenario fits the Holocene to a first approximation, but the late Pleistocene is great puzzle. Large-brained hominins existed in Africa and west Eurasia of perhaps 150,000 years with, at best, slow rates of technical innovation. The most sophisticated societies of the last glacial period appear after 50,000 years ago and were apparently restricted to west and north-central Eurasia and North Africa. These patterns have no simple, commonly accepted explanation. We argue that increased high-frequency climate change around 70,000–50,000 years ago may have tipped the balance between humans and their competitor- predators, such as lions and wolves, in favor of humans. At the same time, technically sophisticated hunters would tend to overharvest their prey. Perhaps the ephemeral appearance of complex tools and symbolic artifacts in Africa after 100,000 years ago resulted from hunting inventions that allowed human populations to expand temporarily before prey over exploitation led to human population and technology collapse. Sustained human populations of moderate size using distinctively advanced Upper Paleolithic artifacts may have existed in west Eurasia because cold, continental northeastern Eurasia–Beringia acted as a protected reserve for prey populations

Beyond the High Ground: A Taxonomy for Earth-Moon System Operations

Situational and space domain awareness in the space domain can no longer be confined to that which is found in geosynchronous orbit. International activities—commercial and military—and threats to the planet itself exist and are increasing across the entire Earth-Moon system. This reality requires a new taxonomy to accurately classify space domain awareness missions and better apply resources to and development of the same. This work presents such a taxonomy for the classification of space domain awareness regions

Black Space versus Blue Space: A Proposed Dichotomy of Future Space Operations

This article will examine the proposed space operations structure by first outlining the historical foundations for differences in maritime and air domain military capabilities, specifically brown-w­ater versus blue-w­ater navies, and “local/ regional” versus “global” airpower. Next, the article will present the concept of black space and blue space in terms of an environment-­specific definition, as well as an examination of the technical capability requirements, mission types, and national prestige and geopolitical considerations underpinning the proposed operation types. Finally, the article will explore how the USSF might support future space exploration within the black-­space and blue-s­pace operations structure