4,235 research outputs found
A stochastic dominance approach to program evaluation with an application to child nutritional status in arid and semi-arid Kenya
Food Consumption/Nutrition/Food Safety,
Directly detecting sub-GeV dark matter with electrons from nuclear scattering
Dark matter (DM) particles with mass in the sub-GeV range are an attractive
alternative to heavier weakly-interacting massive particles, but direct
detection of such light particles is challenging. If however DM-nucleus
scattering leads to ionisation of the recoiling atom, the resulting electron
may be detected even if the nuclear recoil is unobservable. We demonstrate that
including this effect significantly enhances direct detection sensitivity to
sub-GeV DM. Existing experiments set world-leading limits, and future
experiments may probe the cross sections relevant for thermal freeze-out.Comment: 8 pages revtex4, 5 figures; v2: analysis updated to include
constraints from XENON1T; accepted for publication in PR
The Flavour of Natural SUSY
An inverted mass hierarchy in the squark sector, as in so-called "natural
supersymmetry", requires non-universal boundary conditions at the mediation
scale of supersymmetry breaking. We propose a formalism to define such boundary
conditions in a basis-independent manner and apply it to generic scenarios
where the third-generation squarks are light, while the first two generation
squarks are heavy and near-degenerate. We show that not only is our formalism
particularly well-suited to study such hierarchical squark mass patterns, but
in addition the resulting soft terms at the TeV scale are manifestly compatible
with the principle of minimal flavour violation, and thus automatically obey
constraints from flavour physics.Comment: 19 pages, 4 figures; v2: matches journal versio
An efficient counting method for the colored triad census
The triad census is an important approach to understand local structure in
network science, providing comprehensive assessments of the observed relational
configurations between triples of actors in a network. However, researchers are
often interested in combinations of relational and categorical nodal
attributes. In this case, it is desirable to account for the label, or color,
of the nodes in the triad census. In this paper, we describe an efficient
algorithm for constructing the colored triad census, based, in part, on
existing methods for the classic triad census. We evaluate the performance of
the algorithm using empirical and simulated data for both undirected and
directed graphs. The results of the simulation demonstrate that the proposed
algorithm reduces computational time many-fold over the naive approach. We also
apply the colored triad census to the Zachary karate club network dataset. We
simultaneously show the efficiency of the algorithm, and a way to conduct a
statistical test on the census by forming a null distribution from 1,000
realizations of a mixing-matrix conditioned graph and comparing the observed
colored triad counts to the expected. From this, we demonstrate the method's
utility in our discussion of results about homophily, heterophily, and
bridging, simultaneously gained via the colored triad census. In sum, the
proposed algorithm for the colored triad census brings novel utility to social
network analysis in an efficient package
Very High Energy Gamma-Ray Observations of the Galactic Centre Region
Recent progress in pushing the sensitivity of the Imaging Atmospheric
Cherenkov Technique into the 10 mCrab regime has enabled first sensitive
observations of the innermost few 100 pc of the Milky Way in Very High Energy
(VHE; >100 GeV) gamma rays. These observations are a valuable tool to
understand the acceleration and propagation of energetic particles near the
Galactic Centre. Remarkably, besides two compact gamma-ray sources, faint
diffuse gamma-ray emission has been discovered with high significance. The
current VHE gamma-ray view of the Galactic Centre region is reviewed, and
possible counterparts of the gamma-ray sources and the origin of the diffuse
emission are discussed. The future prospects for VHE Galactic Centre
observations are discussed based on order-of-magnitude estimates for a CTA type
array of telescopes.Comment: 11 pages, 7 figures, Invited talk at the "4th Heidelberg
International Symposium on High Energy Gamma-Ray Astronomy 2008
Lidar Remote Sensing Of Forest Canopy Structure: An Assessment Of The Accuracy Of Lidar And Its Relationship To Higher Trophic Levels
Light detection and ranging (LiDAR) data can provide detailed information about three-dimensional forest horizontal and vertical structure that is important to forest productivity and wildlife habitat. Indeed, LiDAR data have been shown to provide accurate estimates to forest structural parameters and measures of higher trophic levels (e.g., avian abundance and diversity). However, links between forest structure and tree function have not been evaluated using LiDAR. This study was designed and scaled to assess the relationship of LiDAR to multiple aspects of forest structure and higher trophic levels (arthropod and bird populations), which included the ground-based collection of percent crown and understory closure, as well as arthropod and avian abundance and diversity data. Additional plot-based measures were added to assess the relationship of LiDAR to forest health and productivity. High-resolution discrete-return LiDAR data (flown summer of 2009) were acquired for the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA. LiDAR data were classified into four canopy structural categories: 1) high crown and high understory closure, 2) high crown and low understory closure, 3) low crown and high understory closure, and 4) low crown and low understory closure. Nearby plots from each of the four LiDAR categories were grouped into blocks to assess the spatial consistency of data. Ground-based measures of forest canopy structure, site, stand and individual tree measures were collected on nine 50 m-plots from each LiDAR category (36 plots total), during summer of 2012. Analysis of variance was used to assess the relationships between LiDAR and a suite of tree function measures. Our results show the novel ability of LiDAR to assess forest health and productivity at the stand and individual tree level. We found significant correspondence between LiDAR categories and our ground-based measures of tree function, including xylem increment growth, foliar nutrition, crown health, and stand mortality. Furthermore, we found consistent reductions in xylem increment growth, decreases in foliar nutrition and crown health, and increases in stand mortality related to high understory closure. This suggests that LiDAR measures can reflect competitive interactions, not just among overstory trees for light, but also interactions between overstory trees and understory vegetation for resources other than light (e.g., nutrients). High-resolution LiDAR data show promise in the assessment of forest health and productivity related to tree function
Idiosyncratic shocks, risk management and welfare dynamics in rural Ghana
International Development, Risk and Uncertainty,
Practical Leadership In Implementing Online Education Programs
The growing presence of online education can become a challenge for academic leaders and institutions to lead, manage, and explore in higher education. Online education can be complex when considering the social presence (Keast, 2022; Quayson, 2022), course development (Martin et al., 2019; Orlando, 2019), and economic outcomes (Burnett & Conley, 2013; Rubin, 2013; Seaman et al., 2019). However, unraveling the fundamentals of practical leadership can help educational leaders to facilitate, maintain, and implement online education programs. The study found published research studies that helped us to extricate the fundamentals of practical leadership in implementing online education programs in the following ways: the process of implementing online education programs, facilitation of the use of the Internet as the delivery method, and curriculum and instructional design. The study findings indicate that educational leaders should invest in high-speed Internet service and learning technologies, provide professional development trainings for students and faculty members, supply faculty members with certificate of completion after training, focus on technology challenges, and ensure that faculty members are recognized as course content curators
A 5-week Personalized Training Workshop To Assess and Evaluate Faculty Members Teaching Online
The authors developed the Skills of Inquiry (SoI) model accompanied by a logic model to assess and evaluate faculty members teaching online. The Skills of Inquiry is based on faculty members’ abilities to understand the online environments, skills development pertaining to online teaching, and acquisition of specific online skills. The Skills of Inquiry model was used to personalize a 5-week workshop training and development module specifically for faculty members teaching online. The training workshop is effective in training faculty members to acquire specific online teaching skills through customized and individualized professional development learning. The training is a self-paced asynchronous online workshop that is suitable for faculty members who are novice, mid-career, and veteran at online teaching. Faculty members would need personal computers or laptops with camera, high-speed Internet service, and learning management systems (LMS) to access training content including video, audio, and PowerPoint. To recognize specific skill competencies to teach online, faculty members must be awarded a digital badge or a micro-credential badge to culminate the experience of the workshop training as an investment in skills development and achievement
- …