On the Feasibility of Extending Social Experiments to Wider Applications

Background: When deciding how to allocate limited funds for social programs, policymakers and program managers increasingly ask for evidence of effectiveness based on studies that rely on solid methodology, providing credible scientific evidence. The basic claim for the “social experiment”—that the “coin flip” of randomization creates two statistically equivalent groups that do not diverge except through an intervention’s effects—makes resulting estimates unbiased. Despite the transparency and conceptual strength of the experimental strategy for revealing the causal connection between an intervention and the outcomes of its participants, the wisdom or feasibility of conducting social experiments is often questioned on a variety of grounds. Purpose: This article defines 15 common concerns about the viability and policy reliability of social experiments, in order to assess how much these issues need constrain the use of the method in providing policy evidence. Setting: NA Intervention: NA Research Design: The research uses the authors’ experience designing and conducting dozens of social experiments to examine the basis for and soundness of each concern.  It  provides examples from the scholarly literature and evaluations in practice of both the problems posed and responses to each issue. Data Collection and Analysis: NA Findings: We conclude that none of the 15 concerns precludes substantially extending the use of randomized experiments as a means of evaluating the impacts of government and foundation social policies and programs

The use of biochar and pyrolysed materials to improve water quality through microcystin sorption separation

Unidad de excelencia María de Maeztu CEX2019-000940-MHarmful algal blooms have increased globally with warming of aquatic environments and increased eutrophication. Proliferation of cyanobacteria (blue-green algae) and the subsequent flux of toxic extracellular microcystins present threats to public and ecosystem health and challenges for remediation and management. Although methods exist, there is currently a need for more environmentally friendly and economically and technologically feasible sorbents. Biochar has been proposed in this regard because of its high porosity, chemical stability, and notable sorption efficiency for removing of cyanotoxins. In light of worsening cyanobacterial blooms and recent research advances, this review provides a timely assessment of microcystin removal strategies focusing on the most pertinent chemical and physical sorbent properties responsible for effective removal of various pollutants from wastewater, liquid wastes, and aqueous solutions. The pyrolysis process is then evaluated for the first time as a method for sorbent production for microcystin removal, considering the suitability and sorption efficiencies of pyrolysed materials and biochar. Inefficiencies and high costs of conventional methods can be avoided through the use of pyrolysis. The significant potential of biochar for microcystin removal is determined by feedstock type, pyrolysis conditions, and the physiochemical properties produced. This review informs future research and development of pyrolysed materials for the treatment of microcystin contaminated aquatic environments

Difficulty of distinguishing product states locally

Non-locality without entanglement is a rather counter-intuitive phenomenon in which information may be encoded entirely in product (unentangled) states of composite quantum systems in such a way that local measurement of the subsystems is not enough for optimal decoding. For simple examples of pure product states, the gap in performance is known to be rather small when arbitrary local strategies are allowed. Here we restrict to local strategies readily achievable with current technology; those requiring neither a quantum memory nor joint operations. We show that, even for measurements on pure product states there can be a large gap between such strategies and theoretically optimal performance. Thus even in the absence of entanglement physically realizable local strategies can be far from optimal for extracting quantum information.Comment: 5 pages, 1 figur

Evolution of Giant Planets in Eccentric Disks

We investigate the interaction between a giant planet and a viscous circumstellar disk by means of high-resolution, two-dimensional hydrodynamical simulations. We consider planet masses that range from 1 to 3 Jupiter masses (Mjup) and initial orbital eccentricities that range from 0 to 0.4. We find that a planet can cause eccentricity growth in a disk region adjacent to the planet's orbit, even if the planet's orbit is circular. Disk-planet interactions lead to growth in a planet's orbital eccentricity. The orbital eccentricities of a 2 Mjup and a 3 Mjup planet increase from 0 to 0.11 within about 3000 orbits. Over a similar time period, the orbital eccentricity of a 1 Mjup planet grows from 0 to 0.02. For a case of a 1 Mjup planet with an initial eccentricity of 0.01, the orbital eccentricity grows to 0.09 over 4000 orbits. Radial migration is directed inwards, but slows considerably as a planet's orbit becomes eccentric. If a planet's orbital eccentricity becomes sufficiently large, e > ~0.2, migration can reverse and so be directed outwards. The accretion rate towards a planet depends on both the disk and the planet orbital eccentricity and is pulsed over the orbital period. Planet mass growth rates increase with planet orbital eccentricity. For e~0.2 the mass growth rate of a planet increases by approximately 30% above the value for e=0. For e > ~0.1, most of the accretion within the planet's Roche lobe occurs when the planet is near the apocenter. Similar accretion modulation occurs for flow at the inner disk boundary which represents accretion toward the star.Comment: 20 pages 16 figures, 3 tables. To appear in The Astrophysical Journal vol.652 (December 1, 2006 issue

Program Applicants as a Comparison Group in Evaluating Training Programs: Theory and a Test

The authors begin with a thorough assessment of the many nonexperimental employment and training program evaluation techniques based on non-random comparison groups. These techniques typically use econometric methods to estimate the effects of employment and training programs by using comparison groups from non-program external sources. Then, recognizing the inherent drawbacks in these methods, Bell, Orr, Blomquist and Cain respond by reintroducing an evaluation method first implemented in the 1960s, the use of internal comparison groups consisting of nonparticipating program applicants. These groups include withdrawals, screen-outs and no-shows of the programs being evaluated in order to solve the selection bias problem. By applying to the program, say the authors, nonparticipating applicants reveal themselves to have some of the same difficult-to-measure, personal characteristics that inspire participants to seek help in response to their current economic situation. The methodology of this technique is updated, then tested against the random experimental findings derived from a controlled job training experiment, the AFDC Homemaker-Home Health Aide Demonstrations. Encouraging results are presented along with useful suggestions for designers and implementers of all types of program evaluations.https://research.upjohn.org/up_press/1080/thumbnail.jp

Methods Used to Evaluate Employment and Training Programs in the Past

The authors begin with a thorough assessment of the many nonexperimental employment and training program evaluation techniques based on non-random comparison groups. These techniques typically use econometric methods to estimate the effects of employment and training programs by using comparison groups from non-program external sources. Then, recognizing the inherent drawbacks in these methods, Bell, Orr, Blomquist and Cain respond by reintroducing an evaluation method first implemented in the 1960s, the use of internal comparison groups consisting of nonparticipating program applicants. These groups include withdrawals, screen-outs and no-shows of the programs being evaluated in order to solve the selection bias problem. By applying to the program, say the authors, nonparticipating applicants reveal themselves to have some of the same difficult-to-measure, personal characteristics that inspire participants to seek help in response to their current economic situation. The methodology of this technique is updated, then tested against the random experimental findings derived from a controlled job training experiment, the AFDC Homemaker-Home Health Aide Demonstrations. Encouraging results are presented along with useful suggestions for designers and implementers of all types of program evaluations.https://research.upjohn.org/up_press/1080/thumbnail.jp

Three-dimensional Disk-Planet Torques in a Locally Isothermal Disk

We determine an expression for the Type I planet migration torque involving a locally isothermal disk, with moderate turbulent viscosity (~0.0005 < alpha < ~0.05), based on three-dimensional nonlinear hydrodynamical simulations. The radial gradients (in a dimensionless logarithmic form) of density and temperature are assumed to be constant near the planet. We find that the torque is roughly equally sensitive to the surface density and temperature radial gradients. Both gradients contribute to inward migration when they are negative. Our results indicate that two-dimensional calculations with a smoothed planet potential, used to account for the effects of the third dimension, do not accurately determine the effects of density and temperature gradients on the three-dimensional torque. The results suggest that substantially slowing or stopping planet migration by means of changes in disk opacity or shadowing is difficult and appears unlikely for a disk that is locally isothermal. The scalings of the torque and torque density with planet mass and gas sound speed follow the expectations of linear theory. We also determine an improved formula for the torque density distribution that can be used in one-dimensional long-term evolution studies of planets embedded in locally isothermal disks. This formula can be also applied in the presence of mildly varying radial gradients and of planets that open gaps. We illustrate its use in the case of migrating super-Earths and determine some conditions sufficient for survival.Comment: 20 pages, 16 figures. To appear in The Astrophysical Journal. Updated with changes and corrections added in proo

Joint measurements of spin, operational locality and uncertainty

Joint, or simultaneous, measurements of non-commuting observables are possible within quantum mechanics, if one accepts an increase in the variances of the jointly measured observables. In this paper, we discuss joint measurements of a spin 1/2 particle along any two directions. Starting from an operational locality principle, it is shown how to obtain a bound on how sharp the joint measurement can be. We give a direct interpretation of this bound in terms of an uncertainty relation.Comment: Accepted for publication in Phys. Rev.

Preparation and characterization of novel magnesium composite/walnut shells-derived biochar for as and p sorption from aqueous solutions

Unidad de excelencia María de Maeztu CEX2019-000940-MElevated or unnatural levels of arsenic (As) and phosphorus (P) concentrations in soils and waterbodies from anthropogenic sources can present significant hazards for both natural ecosystems and human food production. Effective, environmentally friendly, and inexpensive materials, such as biochar, are needed to reduce mobility and bioavailability of As and P. While biochar features several physicochemical properties that make it an ideal contaminant sorbent, certain modifications such as mineral-impregnation can improve sorption efficiencies for targeted compounds. Here, we conducted sorption experiments to investigate and quantify the potential utility of magnesium (Mg) for improving biochar sorption efficiency of P and As. We synthesized a Mg-modified walnut shells-derived biochar and characterized its ability to remove As and P from aqueous solutions, thereby mitigating losses of valuable P when needed while, at the same time, immobilizing hazardous As in ecosystems. SEM-EDX, FTIR and elemental analysis showed morphological and functional changes of biochar and the formation of new Mg-based composites (MgO, MgOHCl) responsible for improved sorption potential capacity by 10 times for As and 20 times for P. Sorption efficiency was attributed to improved AEC, higher SSA, chemical forms of sorbates and new sorption site formations. Synthetized Mg-composite/walnut shell-derived biochar also removed >90% of P from real samples of wastewater, indicating its potential suitability for contaminated waterbody remediation