88 research outputs found
Selective and low temperature transition metal intercalation in layered tellurides
Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80?°C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid
Van der Waals heterostructures
Research on graphene and other two-dimensional atomic crystals is intense and
likely to remain one of the hottest topics in condensed matter physics and
materials science for many years. Looking beyond this field, isolated atomic
planes can also be reassembled into designer heterostructures made layer by
layer in a precisely chosen sequence. The first - already remarkably complex -
such heterostructures (referred to as 'van der Waals') have recently been
fabricated and investigated revealing unusual properties and new phenomena.
Here we review this emerging research area and attempt to identify future
directions. With steady improvement in fabrication techniques, van der Waals
heterostructures promise a new gold rush, rather than a graphene aftershock
Ecological commonalities among pelagic fishes: comparison of freshwater ciscoes and marine herring and sprat
Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace and ciscoes, Coregonus spp.) and marine clupeids (herring, Clupea harengus, and sprat, Sprattus sprattus). We further elucidate potential effects of climate warming on these groups of fish based on the ecological features of coregonids and clupeids documented in the previous parts of the review. These freshwater and marine fishes share a surprisingly high number of similarities. Both groups are relatively short-lived, pelagic planktivorous fishes. The genetic differentiation of local populations is weak and seems to be in part correlated to an astonishing variability of spawning times. The discrete thermal window of each species influences habitat use, diel vertical migrations and supposedly also life history variations. Complex life cycles and preference for cool or cold water make all species vulnerable to the effects of global warming. It is suggested that future research on the functional interdependence between spawning time, life history characteristics, thermal windows and genetic differentiation may profit from a systematic comparison of the patterns found in either coregonids or clupeids
Skeletal abnormalities of acrogeria, a progeroid syndrome
We report the skeletal abnormalities in a 4 1/2-year-old boy with acrogeria, a progeroid syndrome of premature aging of the skin without the involvement of internal organs seen in Hutchinson-Gilford progeria syndrome. Acro-osteolysis of the distal phalanges, delayed cranial suture closure with wormian bones, linear lucent defects of the metaphyses, and antegonial notching of the mandible are the predominant skeletal features of the disorder. The skeletal features described in 21 other reported cases of acrogeria are summarized.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46786/1/256_2004_Article_BF00350541.pd
Addressing food and nutrition insecurity in the Caribbean through domestic smallholder farming system innovation
Structural conditions underlying the development of CARICOM’s two-tiered agricultural innovation system depict diverse drivers of change over time, versus institutional inertia of export-oriented formal institutions and the neglect of informal domestic markets. Key principles of taking an agroecological approach would include: supporting diversity and redundancy, building connectivity, managing slow variables and feedbacks, improving understanding of socioecological systems as complex adaptive systems, and encouraging polycentric governance systems. In this paper, we review the conditions that have been undermining sustainable food and nutrition security in the Caribbean, focusing on issues of history, economy, and innovation
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects
This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searches. The DUNE far detector will be a very large modular liquid argon time-projection chamber (LArTPC) located deep underground, coupled to the LBNF multi-megawatt wide-band neutrino beam. DUNE will also have a high-resolution and high-precision near detector
The Single-Phase ProtoDUNE Technical Design Report
ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report
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