Spin and orbital quantum numbers play a key role in the physics of Mott insulators, but in most systems they are connected only indirectly--via the Pauli exclusion principle and the Coulomb ...interaction. Iridium-based oxides (iridates) introduce strong spin-orbit coupling directly, such that these numbers become entwined together and the Mott physics attains a strong orbital character. In the layered honeycomb iridates this is thought to generate highly spin-anisotropic magnetic interactions, coupling the spin to a given spatial direction of exchange and leading to strongly frustrated magnetism. Here we report a new iridate structure that has the same local connectivity as the layered honeycomb and exhibits striking evidence for highly spin-anisotropic exchange. The basic structural units of this material suggest that a new family of three-dimensional structures could exist, the 'harmonic honeycomb' iridates, of which the present compound is the first example.
Here, we report a structure–function study of imine covalent organic frameworks (COFs) comparing a series of novel fluorine‐containing monomers to their non‐fluorinated analogues. We found that the ...fluorine‐containing monomers produced 2D‐COFs with not only greatly improved surface areas (over 2000 m2 g−1 compared to 760 m2 g−1 for the non‐fluorinated analogue), but also with improved crystallinity and larger, more defined pore diameters. We then studied the formation of these COFs under varying reaction times and temperatures to obtain a greater insight into their mechanism of formation.
Stack ‘em up: A strategy to significantly improve the crystallinity and the surface area of 2D covalent organic frameworks (COFs), by simple variation in the electronic structure of non‐planar precursors through fluorination, is presented (see figure).
Context.
We present results from the first recorded stellar occultation by the large trans-Neptunian object (174567) Varda that was observed on September 10, 2018. Varda belongs to the ...high-inclination dynamically excited population, and has a satellite, Ilmarë, which is half the size of Varda.
Aims.
We determine the size and albedo of Varda and constrain its 3D shape and density.
Methods.
Thirteen different sites in the USA monitored the event, five of which detected an occultation by the main body. A best-fitting ellipse to the occultation chords provides the instantaneous limb of the body, from which the geometric albedo is computed. The size and shape of Varda are evaluated, and its bulk density is constrained using Varda’s mass as is known from previous works.
Results.
The best-fitting elliptical limb has semi-major (equatorial) axis of (383 ± 3) km and an apparent oblateness of 0.066 ± 0.047, corresponding to an apparent area-equivalent radius
R
′
equiv
= (370±7) km and geometric albedo
p
v
= 0.099 ± 0.002 assuming a visual absolute magnitude
H
V
= 3.81 ± 0.01. Using three possible rotational periods for the body (4.76, 5.91, and 7.87 h), we derive corresponding MacLaurin solutions. Furthermore, given the low-amplitude (0.06 ± 0.01) mag of the single-peaked rotational light-curve for the aforementioned periods, we consider the double periods. For the 5.91 h period (the most probable) and its double (11.82 h), we find bulk densities and true oblateness of
ρ
= (1.78 ± 0.06) g cm
−3
,
ɛ
= 0.235 ± 0.050, and
ρ
= (1.23 ± 0.04) g cm
−3
,
ɛ
= 0.080 ± 0.049. However, it must be noted that the other solutions cannot be excluded just yet.
The purpose of this article is to provide information on the history, accomplishments, and future direction of the Bt brinjal (eggplant) program in Bangladesh, formerly under the Agricultural ...Biotechnology Support Project II, now the South Asia Eggplant Improvement Partnership (SAEIP). The India-based Maharashtra Hybrid Seed Company (Mahyco) developed an eggplant expressing Cry1Ac (EE-1) for control of the eggplant fruit and shoot borer (EFSB). In a partnership among Mahyco, USAID, Sathguru Management Consultants and Cornell University EE-1 was provided to the Bangladesh Agricultural Research Institute (BARI) who bred it into local varieties. After regulatory approval, four varieties were distributed to 20 farmers who harvested Bt brinjal in 2014. Adoption in subsequent years has increased rapidly so that, in 2018, 27,012 farmers used this technology. This article provides background information on the process leading up to current adoption levels, the level of control of EFSB achieved and the economic benefits of Bt brinjal. Efforts on stewardship, farmer training and communication are discussed. In order to ensure the long-term future of the partnership, we discuss the need to enhance involvement of the private sector in the production and stewardship of Bt eggplant. Bt brinjal is the first genetically engineered crop to be commercially released in Bangladesh, and other GE crops are in the pipeline. Hence, success of the Bt brinjal partnership is likely to affect the future of other GE crops in Bangladesh, as well as other parts of the world where biotechnology is needed for food security and environmental safety.
2D covalent organic frameworks (COFs) are a class of crystalline, porous, polymeric materials that have demonstrated promise in a variety of energy storage applications. The use of ...fluorine‐containing monomers produces 2D‐COFs with not only greatly improved surface areas (over 2000 m2 g−1 compared to 760 m2 g−1 for the non‐fluorinated analogue), but also with improved crystallinity and larger, better defined pore diameters. In their Communication on page 4255 ff., R. A. Smaldone et al. report on the formation of these COFs under varying reaction times and temperatures to obtain a greater insight into their mechanism of formation.
As an increasing number of individuals go to work in the nonprofit sector, nonprofit managers need support on how best to build their human resource management (HRM) capacity. They need to know which ...systems to examine, what questions to ask, and how to ensure they are managing people in a legal manner and as effectively as possible, given their particular resource constraints. Important questions include: Do we have a clear philosophy, one that aligns with our nonprofit mission and values and allows us to treat our employees as the professionals they are? How do we select, develop, and retain the best people who will produce high-value, high performance work, and how do we do so with limited resources? How do we effectively manage our mix of volunteers and paid staff? What do we need to consider to ensure diverse people work together in a harmonious fashion? With all-new chapters written by the top scholars in the field of nonprofit HRM, these are but a few of the many questions that are addressed in this timely volume.
These scholars delve into their particular areas of expertise, offering a comprehensive look at theories and trends; legal and ethical issues; how to build HRM from recruitment, management, labor relations, to training and appraisal; as well as topics in diversity, technology, and paid versus volunteer workforce management. This essential handbook offers all core topic coverage as well as countless insider insights, additional resource lists, and tool sets for practical application. With chapters grounded in existing research, but also connecting research to practice for those in the field, The Nonprofit Human Resource Management Handbook will be required reading for a generation of scholars, students, and practitioners of nonprofit human resource management.
“If I were to make a list of scholars who we should hire to assemble current thinking on human resource management in the nonprofit sector, Sowa and Word would be at the top of my list. Lo, it seems that these two have been doing just that. They have organized an impressive panoply of both young and established nonprofit sector scholars who represent our best current thinking on strategic human resource management. Interested readers will be able to pick and choose among its offerings. Some teachers will assign the entire volume in their college courses on nonprofit HRM.”
Mark Hager, Arizona State University, USA
“Sowa and Word have contributed an outstanding new guide for both nonprofit managers and scholars, in The Nonprofit Resource Management Handbook. This book offers an impressive collection of thoughtfully-written and practical pieces by leading voices in the field. Comprehensive in scope, Sowa and Word cover critical topics ranging from how to attract the best and brightest employees and volunteers into the sector, to managing and cultivating diversity, to applications of technology in human resource management, and everything in between. This book serves as a valuable resource that I look forward to sharing with my students undertaking careers in the nonprofit sector.”
Kelly LaRoux, The University of Chicago at Illinois, USA
“The Nonprofit Human Resource Management Handbook is an excellent confluence of the state-of-art research on human resources in nonprofit organizations and the practical matters confronting nonprofit managers seeking to effectively deploy their human capital. Sowa and Word and their outstanding colleagues have compiled an accessible, yet rigorous, resource that benefits both scholars and practitioners by highlighting critical issues that nonprofit organizations must successfully navigate to recruit and retain talented workers in the current environment. This will certainly be a much-used textbook in nonprofit management courses. I wish I would have had this book when I was a student!”
Rebecca Nesbit, University of Georgia, USA
Herein we report a combined experimental and computational study on the effect of fluorine atom incorporation on the materials properties of azine-linked COFs. We found that increasing the ratio of ...fluorinated to non-fluorinated monomers led to substantial improvements in both crystallinity and porosity. Computational models suggest that this improvement might be explained by a substantial energetic stabilization in the face-to-face stacking interaction of the fluorinated COF monomers.
Despite recent advances in field research on white sharks (Carcharodon carcharias) in several regions around the world, opportunistic capture and sighting records remain the primary source of ...information on this species in the northwest Atlantic Ocean (NWA). Previous studies using limited datasets have suggested a precipitous decline in the abundance of white sharks from this region, but considerable uncertainty in these studies warrants additional investigation. This study builds upon previously published data combined with recent unpublished records and presents a synthesis of 649 confirmed white shark records from the NWA compiled over a 210-year period (1800-2010), resulting in the largest white shark dataset yet compiled from this region. These comprehensive records were used to update our understanding of their seasonal distribution, relative abundance trends, habitat use, and fisheries interactions. All life stages were present in continental shelf waters year-round, but median latitude of white shark occurrence varied seasonally. White sharks primarily occurred between Massachusetts and New Jersey during summer and off Florida during winter, with broad distribution along the coast during spring and fall. The majority of fishing gear interactions occurred with rod and reel, longline, and gillnet gears. Historic abundance trends from multiple sources support a significant decline in white shark abundance in the 1970s and 1980s, but there have been apparent increases in abundance since the 1990s when a variety of conservation measures were implemented. Though the white shark's inherent vulnerability to exploitation warrants continued protections, our results suggest a more optimistic outlook for the recovery of this iconic predator in the Atlantic.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Herein we report a combined experimental and computational study on the effect of fluorine atom incorporation on the materials properties of azine-linked COFs. We found that increasing the ratio of ...fluorinated to non-fluorinated monomers led to substantial improvements in both crystallinity and porosity. Computational models suggest that this improvement might be explained by a substantial energetic stabilization in the face-to-face stacking interaction of the fluorinated COF monomers.
Herein we report a combined experimental and computational study on the effect of fluorine atom incorporation on the materials properties of azine-linked COFs.
When identifying potential trophic cascades, it is important to clearly establish the trophic linkages between predators and prey with respect to temporal abundance, demographics, distribution, and ...diet. In the northwest Atlantic Ocean, the depletion of large coastal sharks was thought to trigger a trophic cascade whereby predation release resulted in increased cownose ray abundance, which then caused increased predation on and subsequent collapse of commercial bivalve stocks. These claims were used to justify the development of a predator-control fishery for cownose rays, the "Save the Bay, Eat a Ray" fishery, to reduce predation on commercial bivalves. A reexamination of data suggests declines in large coastal sharks did not coincide with purported rapid increases in cownose ray abundance. Likewise, the increase in cownose ray abundance did not coincide with declines in commercial bivalves. The lack of temporal correlations coupled with published diet data suggest the purported trophic cascade is lacking the empirical linkages required of a trophic cascade. Furthermore, the life history parameters of cownose rays suggest they have low reproductive potential and their populations are incapable of rapid increases. Hypothesized trophic cascades should be closely scrutinized as spurious conclusions may negatively influence conservation and management decisions.
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