1,134 research outputs found
Identifying candidate hosts for quantum defects via data mining
Atom-like defects in solid-state hosts are promising candidates for the
development of quantum information systems, but despite their importance, the
host substrate/defect combinations currently under study have almost
exclusively been found serendipitously. Here we systematically evaluate the
suitability of host materials by applying a combined four-stage data mining and
manual screening process to all entries in the Materials Project database, with
literature-based experimental confirmation of band gap values. We identify 580
viable host substrates for quantum defect introduction and use in quantum
information systems. While this constitutes a significant increase in the
number of known and potentially viable material systems, it nonetheless
represents a significant (99.54%) reduction from the total number of known
inorganic phases, and the application of additional selection criteria for
specific applications will reduce their number even further. The screening
principles outlined may easily be applied to previously unrealized phases and
other technologically important materials systems.Comment: Currently under consideration at npj Computational Material
Ocean processes at the Antarctic continental slope
The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean-atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water mass properties of the region. Dynamics at the continental slope are key for correctly modelling climate, yet their small spatial scale presents challenges both for ocean modelling and for observational studies. Cross-slope exchange processes are also vital for the flux of nutrients such as iron from the continental shelf into the mixed layer of the Southern Ocean. An © 2014 The Authors
A VLA Search for Water Masers in Six HII Regions: Tracers of Triggered Low-Mass Star Formation
We present a search for water maser emission at 22 GHz associated with young
low-mass protostars in six HII regions -- M16, M20, NGC 2264, NGC 6357, S125,
and S140. The survey was conducted with the NRAO Very Large Array from 2000 to
2002. For several of these HII regions, ours are the first high-resolution
observations of water masers. We detected 16 water masers: eight in M16, four
in M20, three in S140, and one in NGC 2264. All but one of these were
previously undetected. No maser emission was detected from NGC 6357 or S125.
There are two principle results to our study. (1) The distribution of water
masers in M16 and M20 does not appear to be random but instead is concentrated
in a layer of compressed gas within a few tenths of a parsec of the ionization
front. (2) Significantly fewer masers are seen in the observed fields than
expected based on other indications of ongoing star formation, indicating that
the maser-exciting lifetime of protostars is much shorter in HII regions than
in regions of isolated star formation. Both of these results confirm
predictions of a scenario in which star formation is first triggered by shocks
driven in advance of ionization fronts, and then truncated approximately 10^5
years later when the region is overrun by the ionization front.Comment: 30 pages, 20 figures, 3 tables. Accepted for publication by ApJ. Full
resolution figures and PS and PDF versions with full-res figures available at
http://eagle.la.asu.edu/healy/preprints/hhc0
A Proposal for Stewardship Support to Private Native Forests in NSW
The Southern Cross Group is proposing a completely new approach to private forest management in NSW based on stewardship support. This means that incentives will be used to encourage landholders to manage their forests in a way that maintains their environmental and other values for the community, without compromising their value as a resource to the farming community. Importantly, the Southern Cross Group system will foster good outcomes through innovation rather than through cumbersome and onerous prescriptions. Private forests in NSW are important as a source of timber as well as for the conservation values they provide to the general community. Landholders should be encouraged to manage them in a way that preserves their productive capacity and their conservation values for the long term. At present, however, neither the current regulatory regime, including the Private Native Forest legislation and proposed code of practice, nor the current market regime encourages sustainable management of the State's private timber resources. The Southern Cross Group has designed an effective and simple way of fostering and rewarding good stewardship of private native forests. Good stewardship may be viewed as a 'duty of care' responsibility that should be enforced by legislation, or as an environmental service that should be recognised and rewarded. The distinction is academic: the reality is that incentives are more effective than punitive regulations. Good environmental outcomes for most forests depend on active management and, especially in the case of private native forests, on incentives for continuing management. The challenge is to devise an equitable scheme that sends the right signals for forest management, is cost-effective to administer, and represents a worthwhile investment in terms of the public good generated. We believe the way forward is with simple, transparent indicators that provide an immediate and ongoing incentive. Under our proposal, landholders will receive an annual cash payment as a reward for progress towards specific outcomes. Rather than complicated targets, we are proposing a simple, two-tiered system that will give enough incentive to landholders to provide the environmental services desired by the community. The first tier rewards and encourages landholders to regenerate more forest, to retain big trees, and to stimulate tree growth on private land. The second tier rewards and encourages stewardship of endangered species and ecological communities. These incentives will be simple to apply and audit, and will encourage landholders to learn about and encourage biodiversity on their land, and to consider it part of their income portfolio. This system will contribute to farmers seeing forests as core business, both as part of their income stream and as part of their environmental stewardship responsibilities. When all farmers view forests in this way, Australia will reap the benefit of forests that are more diverse and productive, and a forest estate that no longer continues to shrink
Boolean analysis identifies CD38 as a biomarker of aggressive localized prostate cancer.
The introduction of serum Prostate Specific Antigen (PSA) testing nearly 30 years ago has been associated with a significant shift towards localized disease and decreased deaths due to prostate cancer. Recognition that PSA testing has caused over diagnosis and over treatment of prostate cancer has generated considerable controversy over its value, and has spurred efforts to identify prognostic biomarkers to distinguish patients who need treatment from those that can be observed. Recent studies show that cancer is heterogeneous and forms a hierarchy of tumor cell populations. We developed a method of identifying prostate cancer differentiation states related to androgen signaling using Boolean logic. Using gene expression data, we identified two markers, CD38 and ARG2, that group prostate cancer into three differentiation states. Cancers with CD38-, ARG2- expression patterns, corresponding to an undifferentiated state, had significantly lower 10-year recurrence-free survival compared to the most differentiated group (CD38+ARG2+). We carried out immunohistochemical (IHC) staining for these two markers in a single institution (Stanford; n = 234) and multi-institution (Canary; n = 1326) cohorts. IHC staining for CD38 and ARG2 in the Stanford cohort demonstrated that combined expression of CD38 and ARG2 was prognostic. In the Canary cohort, low CD38 protein expression by IHC was significantly associated with recurrence-free survival (RFS), seminal vesicle invasion (SVI), extra-capsular extension (ECE) in univariable analysis. In multivariable analysis, ARG2 and CD38 IHC staining results were not independently associated with RFS, overall survival, or disease-specific survival after adjusting for other factors including SVI, ECE, Gleason score, pre-operative PSA, and surgical margins
Restricting sugar or carbohydrate intake does not impact physical activity level or energy intake over 24 h despite changes in substrate use : A randomised crossover study in healthy men and women
Purpose
To determine the effects of dietary sugar or carbohydrate restriction on physical activity energy expenditure, energy intake, and physiological outcomes across 24 h.
Methods
In a randomized, open-label crossover design, twenty-five healthy men (n = 10) and women (n = 15) consumed three diets over a 24-h period: moderate carbohydrate and sugar content (MODSUG = 50% carbohydrate [20% sugars], 15% protein, 35% fat); low sugar content (LOWSUG = 50% carbohydrate [< 5% sugars], 15% protein, 35% fat); and low carbohydrate content (LOWCHO = 8% carbohydrate [< 5% sugars], 15% protein, 77% fat). Postprandial metabolic responses to a prescribed breakfast (20% EI) were monitored under laboratory conditions before an ad libitum test lunch, with subsequent diet and physical activity monitoring under free-living conditions until blood sample collection the following morning.
Results
The MODSUG, LOWSUG and LOWCHO diets resulted in similar mean [95%CI] rates of both physical activity energy expenditure (771 [624, 919] vs. 677 [565, 789] vs. 802 [614, 991] kcal·d−1; p = 0.29] and energy intake (2071 [1794, 2347] vs. 2195 [1918, 2473] vs. 2194 [1890, 2498] kcal·d−1; P = 0.34), respectively. The LOWCHO condition elicited the lowest glycaemic and insulinaemic responses to breakfast (P < 0.01) but the highest 24-h increase in LDL-cholesterol concentrations (P < 0.001), with no differences between the MODSUG and LOWSUG treatments. Leptin concentrations decreased over 24-h of consuming LOWCHO relative to LOWSUG (p < 0.01).
Conclusion
When energy density is controlled for, restricting either sugar or total dietary carbohydrate does not modulate physical activity level or energy intake over a 24-h period (~ 19-h free-living) despite substantial metabolic changes.
Clinical trials registration ID
NCT03509610, https://clinicaltrials.gov/show/NCT0350961
Narrow optical linewidths in erbium implanted in TiO
Atomic and atom-like defects in the solid-state are widely explored for
quantum computers, networks and sensors. Rare earth ions are an attractive
class of atomic defects that feature narrow spin and optical transitions that
are isolated from the host crystal, allowing incorporation into a wide range of
materials. However, the realization of long electronic spin coherence times is
hampered by magnetic noise from abundant nuclear spins in the most widely
studied host crystals. Here, we demonstrate that Er ions can be
introduced via ion implantation into TiO, a host crystal that has not been
studied extensively for rare earth ions and has a low natural abundance of
nuclear spins. We observe efficient incorporation of the implanted Er
into the Ti site (40% yield), and measure narrow inhomogeneous spin and
optical linewidths (20 and 460 MHz, respectively) that are comparable to
bulk-doped crystalline hosts for Er. This work demonstrates that ion
implantation is a viable path to studying rare earth ions in new hosts, and is
a significant step towards realizing individually addressed rare earth ions
with long spin coherence times for quantum technologies
Effect of Plain Versus Sugar-Sweetened Breakfast on Energy Balance and Metabolic Health : A Randomized Crossover Trial
We would like to thank Pippa Heath for her help with randomization, our participants, and Dr. Graham Horgan for statistical advice. Funding Information Economic and Social Research Council. Grant Number: ES/J50015X/1 Biotechnology and Biological Sciences Research Council (BBSRC) GlaxoSmithKline Lucozade Ribena Suntory Kellogg’s Nestlé PepsiCo Sugar Nutrition UK Danone Baby Nutrition the Alpro Foundation Kellogg Europe Unilever Volac International The Collagen Research Institute British Summer FruitsPeer reviewedPublisher PD
Strong Purcell enhancement of an optical magnetic dipole transition
Engineering the local density of states with nanophotonic structures is a
powerful tool to control light-matter interactions via the Purcell effect. At
optical frequencies, control over the electric field density of states is
typically used to couple to and manipulate electric dipole transitions.
However, it is also possible to engineer the magnetic density of states to
control magnetic dipole transitions. In this work, we experimentally
demonstrate the optical magnetic Purcell effect using a single rare earth ion
coupled to a nanophotonic cavity. We engineer a new single photon emitter,
Er in MgO, where the electric dipole decay rate is strongly suppressed
by the cubic site symmetry, giving rise to a nearly pure magnetic dipole
optical transition. This allows the unambiguous determination of a magnetic
Purcell factor . We further extend this technique to realize a
magnetic dipole spin-photon interface, performing optical spin initialization
and readout of a single Er electron spin. This work demonstrates the
fundamental equivalence of electric and magnetic density of states engineering,
and provides a new tool for controlling light-matter interactions for a broader
class of emitters
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