Miniaturized Laser Heterodyne Radiometer (LHR) for Measurements of Greenhouse Gases in the Atmospheric Column

This passive laser heterodyne radiometer (LHR) instrument simultaneously measures multiple trace gases in the atmospheric column including carbon dioxide (CO2) and methane (CH4), and resolves their concentrations at different altitudes. This instrument has been designed to operate in tandem with the passive aerosol sensor currently used in AERONET (an established network of more than 450 ground aerosol monitoring instruments worldwide). Because aerosols induce a radiative effect that influences terrestrial carbon exchange, simultaneous detection of aerosols with these key carbon cycle gases offers a uniquely comprehensive measurement approach. Laser heterodyne radiometry is a technique for detecting weak signals that was adapted from radio receiver technology. In a radio receiver, a weak input signal from a radio antenna is mixed with a stronger local oscillator signal. The mixed signal (beat note, or intermediate frequency) has a frequency equal to the difference between the input signal and the local oscillator. The intermediate frequency is amplified and sent to a detector that extracts the audio from the signal. In the LHR instrument described here, sunlight that has undergone absorption by the trace gas is mixed with laser light at a frequency matched to a trace gas absorption feature in the infrared (IR). Mixing results in a beat signal in the RF (radio frequency) region that can be related to the atmospheric concentration. For a one-second integration, the estimated column sensitivities are 0.1 ppmv for CO2, and <1 ppbv for CH4. In addition to producing a standalone ground measurement product, this instrument could be used to calibrate/validate four Earth observing missions: ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons), OCO-2 (Orbiting Carbon Observatory), OCO-3, and GOSAT (Greenhouse gases Observational SATellite). The only network that currently measures CO2 and CH4 in the atmospheric column is TCCON (Total Carbon Column Observing Network), and only two of its 16 operational sites are in the United States. TCCON data is used for validation of GOSAT data, and will be used for OCO-2 validation. While these Fourier-transform spectrometers (FTS) can measure the largest range of trace gases, the network is severely limited due to the high cost and extreme size of these instruments (these occupy small buildings and require personnel for operation). The LHR/AERONET instrument offers a significantly smaller (carry-on luggage size) autonomous instrument that can be incorporated into AERONET s much larger (450 instruments) global network

Hybrid photonic circuit for multiplexed heralded single photons

A key resource for quantum optics experiments is an on-demand source of single and multiple photon states at telecommunication wavelengths. This letter presents a heralded single photon source based on a hybrid technology approach, combining high efficiency periodically poled lithium niobate waveguides, low-loss laser inscribed circuits, and fast (>1 MHz) fibre coupled electro-optic switches. Hybrid interfacing different platforms is a promising route to exploiting the advantages of existing technology and has permitted the demonstration of the multiplexing of four identical sources of single photons to one output. Since this is an integrated technology, it provides scalability and can immediately leverage any improvements in transmission, detection and photon production efficiencies.Comment: 5 pages, double column, 3 figure

3,3′-Dibromo-5,5′-di-tert-butyl-2,2′-dimethoxy­biphen­yl

The title compound, C22H28Br2O2, crystallizes in a staggered arrangement to minimize the inter­actions of its ortho substituents, with a dihedral angle of 84.2 (3)° between the two aromatic rings. Short C—H⋯O hydrogen-bonding inter­actions between meth­oxy groups result in a one-dimensional polymeric chain of mol­ecules lying parallel to the b axis. One tert-butyl group is disordered equally over two positions

Content is not Context: Radical Transparency and the Acknowledgement of Informational Palimpsests in Online Display.

Whether for print or for the internet, dividing structure and content—the layer approach used in modern web development—has influenced our modern notions of textual presentation. Conscious of it or not, popular conceptions of “content” treat the text as a Platonic ideal loating in the cloud, divorced from any mechanisms of production or display. Since the presentation and display layers are handled separately in most modern web and publishing tools, the underlying assumption is that content can fluidly it any container it is placed into, like water poured into beakers of differing shape, but similar volume. As scholars of medieval manuscript and early print culture can attest, however, this is ultimately a dangerous misconception

Integrated spatial multiplexing of heralded single photon sources

The non-deterministic nature of photon sources is a key limitation for single photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon correlated photon pair sources, demonstrating a 62.4% increase in the heralded single photon output without an increase in unwanted multi-pair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two photon interference, required at the core of optical quantum computing and quantum communication protocols.Comment: 10 pages, 3 figures, comments welcom

Strong cardiovascular prognostic implication of quantitative left atrial contractile function assessed by cardiac magnetic resonance imaging in patients with chronic hypertension

<p>Abstract</p> <p>Background</p> <p>Progressive left ventricular (LV) diastolic dysfunction due to hypertension (HTN) alters left atrial (LA) contractile function in a predictable manner. While increased LA size is a marker of LV diastolic dysfunction and has been shown to be predictive of adverse cardiovascular outcomes, the prognostic significance of altered LA contractile function is unknown.</p> <p>Methods</p> <p>A consecutive group of patients with chronic hypertension but without significant valvular disease or prior MI underwent clinically-indicated CMR for assessment of left ventricular (LV) function, myocardial ischemia, or viability. Calculation of LA volumes used in determining LA emptying functions was performed using the biplane area-length method.</p> <p>Results</p> <p>Two-hundred and ten patients were included in this study. During a median follow-up of 19 months, 48 patients experienced major adverse cardiac events (MACE), including 24 deaths. Decreased LA contractile function (LAEF_Contractile) demonstrated strong unadjusted associations with patient mortality, non-fatal events, and all MACE. For every 10% reduction of LAEF_Contractile, unadjusted hazards to MACE, all-cause mortality, and non-fatal events increased by 1.8, 1.5, and 1.4-folds, respectively. In addition, preservation of the proportional contribution from LA contraction to total diastolic filling (Contractile/Total ratio) was strongly associated with lower MACE and patient mortality. By multivariable analyses, LAEF_Contractilewas the strongest predictor in each of the best overall models of MACE, all-cause mortality, and non-fatal events. Even after adjustment for age, gender, left atrial volume, and LVEF, LAEF_Contractilemaintained strong independent associations with MACE (p < 0.0004), all-cause mortality (p < 0.0004), and non-fatal events (p < 0.0004).</p> <p>Conclusions</p> <p>In hypertensive patients at risk for left ventricular diastolic dysfunction, a decreased contribution of LA contractile function to ventricular filling during diastole is strongly predictive of adverse cardiac events and death.</p

Comparative genomics of flowering behavior in Cannabis sativa

Cannabis sativa L. is a phenotypically diverse and multi-use plant used in the production of fiber, seed, oils, and a class of specialized metabolites known as phytocannabinoids. The last decade has seen a rapid increase in the licit cultivation and processing of C. sativa for medical end-use. Medical morphotypes produce highly branched compact inflorescences which support a high density of glandular trichomes, specialized epidermal hair-like structures that are the site of phytocannabinoid biosynthesis and accumulation. While there is a focus on the regulation of phytocannabinoid pathways, the genetic determinants that govern flowering time and inflorescence structure in C. sativa are less well-defined but equally important. Understanding the molecular mechanisms that underly flowering behavior is key to maximizing phytocannabinoid production. The genetic basis of flowering regulation in C. sativa has been examined using genome-wide association studies, quantitative trait loci mapping and selection analysis, although the lack of a consistent reference genome has confounded attempts to directly compare candidate loci. Here we review the existing knowledge of flowering time control in C. sativa, and, using a common reference genome, we generate an integrated map. The co-location of known and putative flowering time loci within this resource will be essential to improve the understanding of C. sativa phenology

Interventions to Improve Social Climate in Acute Mental Health Inpatient Settings: Systematic Review of Content and Outcomes

Introduction: Quantification of the social climate of mental health care environments has received considerable attention. Investigations of the resulting measures indicate that social climate is associated with individual outcomes including patient satisfaction and staff burnout. Interest has grown in developing interventions to improve social climate in anticipation of subsequent related benefits. This study aimed to identify and critically review research about the effectiveness of interventions for improving social climate in inpatient adult acute mental health settings. Methods: Systematic review reported in line with the Preferred Reporting Items for Systematic reviews and Meta-Analyses. Comprehensive terms were used to search multiple electronic databases from inception to July 2019. Information about intervention type(s), complexity was extracted and study quality was assessed. Results: Twenty-three papers met inclusion criteria of which 20 used a pretest–posttest study design and three employed randomized and/or controlled designs. Interventions were environmental/structural, operational/process-oriented and developmental/person-oriented in nature and they ranged in complexity. The Ward Atmosphere Scale was the most common outcome measure used. Following quality assessment, six studies were judged to be sufficiently robust in terms of quality, theory-base, user-inclusion, and outcomes evaluation to contribute credibly to the evidence base. Of these, four complex person- and process-oriented intervention studies and two less complex structural/environmental intervention studies resulted in positive outcomes. Conclusion: There is limited strong evidence that interventions positively influence measures of ward social climate in acute adult mental health settings. Such measures should not be the sole criterion of success when evaluating change. Decisions about implementing change to improve social climate should be informed by meaningful proxy measures including the views and preferences of service users and other stakeholders. Studies using stronger designs are required to establish the ability of interventions to improve social climate