High-efficiency degenerate four wave-mixing in triply resonant nanobeam cavities

We demonstrate high-efficiency, degenerate four-wave mixing in triply resonant Kerr $\chi^(3)$ photonic crystal (PhC) nanobeam cavities. Using a combination of temporal coupled mode theory and nonlinear finite-difference time-domain (FDTD) simulations, we study the nonlinear dynamics of resonant four-wave mixing processes and demonstrate the possibility of observing high-efficiency limit cycles and steady-state conversion corresponding to $\approx 100$% depletion of the pump light at low powers, even including effects due to losses, self- and cross-phase modulation, and imperfect frequency matching. Assuming operation in the telecom range, we predict close to perfect quantum efficiencies at reasonably low $\sim$ 50 mW input powers in silicon micrometer-scale cavities

Imaging X-ray spectrometer

An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging

Angiotensin II inhibits growth of cultured embryonic renomedullary interstitial cells through the AT2 receptor

Angiotensin II inhibits growth of cultured embryonic renomedullary interstitial cells through the AT2 receptor. The high abundance of angiotensin II (Ang II) AT2, relative to the AT1 receptor subtype in developing kidneys may be related to their potential as mediators of cell growth, although little evidence exists to support this concept. Renomedullary interstitial cells (RMICs) differentiate early in embryonic kidneys and are important in subsequent nephron development. These cells have been shown in vivo to possess AT2 binding sites, although the functional significance of these sites remains unknown. The aim of the current investigation was to examine the actions of Ang II on cultured embryonic renomedullary interstitial cells (ERMICs). 125I-[Sar1, Ile8]Ang II specifically bound to AT1 and AT2 receptors on ERMICs, and their mRNAs were detected by reverse transcription—polymerase chain reaction (RT-PCR). Angiotensin II (10−6M) increased intracellular IP3 concentrations at 20 seconds, and decreased intracellular cAMP concentrations after 10 minutes. Angiotensin II (10−6M) induced an increase in [3H]thymidine incorporation, mediated through the AT1 receptor subtype. Basic fibroblast growth factor (bFGF; 20 ng/ml) also increased 3[H]thymidine incorporation after 24 hours of treatment, an effect that was attenuated by subsequent addition of Ang II (10−6M). This antiproliferative action of Ang II was blocked by PD 123319 (10−6M), an AT2 receptor antagonist, and was not affected by losartan (10−6M), an AT1 receptor antagonist. These results indicate a dual role for Ang II in regulating ERMIC mitogenesis: a growth stimulating effect mediated by the AT1 receptor subtype, and an antiproliferative effect mediated by the AT2 receptor subtype

The Outstanding Decisions of the United States Supreme Court in 1954

We perform a kinematic and morphological analysis of 44 star-forming galaxies at z ̃ 2 in the COSMOS legacy field using near-infrared spectroscopy from Keck/MOSFIRE and F160W imaging from CANDELS/3D-HST as part of the ZFIRE survey. Our sample consists of cluster and field galaxies from 2.0 < z < 2.5 with K-band multi-object slit spectroscopic measurements of their Hα emission lines. Hα rotational velocities and gas velocity dispersions are measured using the Heidelberg Emission Line Algorithm (HELA), which compares directly to simulated 3D data cubes. Using a suite of simulated emission lines, we determine that HELA reliably recovers input S 0.5 and angular momentum at small offsets, but V 2.2/σ g values are offset and highly scattered. We examine the role of regular and irregular morphology in the stellar mass kinematic scaling relations, deriving the kinematic measurement S 0.5, and finding {log}({S}0.5)=(0.38+/- 0.07){log}(M/{M}☉ -10)+(2.04+/- 0.03) with no significant offset between morphological populations and similar levels of scatter (̃0.16 dex). Additionally, we identify a correlation between M ⋆ and V 2.2/σ g for the total sample, showing an increasing level of rotation dominance with increasing M ⋆, and a high level of scatter for both regular and irregular galaxies. We estimate the specific angular momenta (j disk) of these galaxies and find a slope of 0.36 ± 0.12, shallower than predicted without mass-dependent disk growth, but this result is possibly due to measurement uncertainty at M ⋆ < 9.5 However, through a Kolmogorov-Smirnov test we find irregular galaxies to have marginally higher j disk values than regular galaxies, and high scatter at low masses in both populations

ZFIRE: The Evolution of the Stellar Mass Tully-Fisher Relation to Redshift 2.0 < Z < 2.5 with MOSFIRE

Using observations made with MOSFIRE on Keck I as part of the ZFIRE survey, we present the stellar mass Tully-Fisher relation at 2.0 < z < 2.5. The sample was drawn from a stellar mass limited, Ks-band selected catalog from ZFOURGE over the CANDELS area in the COSMOS field. We model the shear of the Halpha emission line to derive rotational velocities at 2.2X the scale radius of an exponential disk (V2.2). We correct for the blurring effect of a two-dimensional PSF and the fact that the MOSFIRE PSF is better approximated by a Moffat than a Gaussian, which is more typically assumed for natural seeing. We find for the Tully-Fisher relation at 2.0 < z < 2.5 that logV2.2 =(2.18 +/- 0.051)+(0.193 +/- 0.108)(logM/Msun - 10) and infer an evolution of the zeropoint of Delta M/Msun = -0.25 +/- 0.16 dex or Delta M/Msun = -0.39 +/- 0.21 dex compared to z = 0 when adopting a fixed slope of 0.29 or 1/4.5, respectively. We also derive the alternative kinematic estimator S0.5, with a best-fit relation logS0.5 =(2.06 +/- 0.032)+(0.211 +/- 0.086)(logM/Msun - 10), and infer an evolution of Delta M/Msun= -0.45 +/- 0.13 dex compared to z < 1.2 if we adopt a fixed slope. We investigate and review various systematics, ranging from PSF effects, projection effects, systematics related to stellar mass derivation, selection biases and slope. We find that discrepancies between the various literature values are reduced when taking these into account. Our observations correspond well with the gradual evolution predicted by semi-analytic models.Comment: 21 pages, 14 figures, 1 appendix. Accepted for publication by Apj, February 28, 201

ZFIRE: Using Hα\alpha equivalent widths to investigate the in situ initial mass function at z~2

We use the ZFIRE survey (http://zfire.swinburne.edu.au) to investigate the high mass slope of the initial mass function (IMF) for a mass-complete (log10(M$_*$/M$_\odot$)~9.3) sample of 102 star-forming galaxies at z~2 using their H$\alpha$ equivalent widths (H$\alpha$-EW) and rest-frame optical colours. We compare dust-corrected H$\alpha$-EW distributions with predictions of star-formation histories (SFH) from PEGASE.2 and Starburst99 synthetic stellar population models. We find an excess of high H$\alpha$-EW galaxies that are up to 0.3--0.5 dex above the model-predicted Salpeter IMF locus and the H$\alpha$-EW distribution is much broader (10--500 \AA) than can easily be explained by a simple monotonic SFH with a standard Salpeter-slope IMF. Though this discrepancy is somewhat alleviated when it is assumed that there is no relative attenuation difference between stars and nebular lines, the result is robust against observational biases, and no single IMF (i.e. non-Salpeter slope) can reproduce the data. We show using both spectral stacking and Monte Carlo simulations that starbursts cannot explain the EW distribution. We investigate other physical mechanisms including models with variations in stellar rotation, binary star evolution, metallicity, and the IMF upper-mass cutoff. IMF variations and/or highly rotating extreme metal poor stars (Z~0.1Z$_\odot$) with binary interactions are the most plausible explanations for our data. If the IMF varies, then the highest H$\alpha$-EWs would require very shallow slopes ($\Gamma$>-1.0) with no one slope able to reproduce the data. Thus, the IMF would have to vary stochastically. We conclude that the stellar populations at z~2 show distinct differences from local populations and there is no simple physical model to explain the large variation in H$\alpha$-EWs at z~2.Comment: Accepted to MNRAS. 43 pages, 27 Figures. Survey website: http://zfire.swinburne.edu.au

ZFIRE: A KECK/MOSFIRE Spectroscopic Survey of Galaxies in Rich Environments at z~2

We present an overview and the first data release of ZFIRE, a spectroscopic redshift survey of star-forming galaxies that utilizes the MOSFIRE instrument on Keck-I to study galaxy properties in rich environments at $1.5<z<2.5$. ZFIRE measures accurate spectroscopic redshifts and basic galaxy properties derived from multiple emission lines. The galaxies are selected from a stellar mass limited sample based on deep near infra-red imaging ($\mathrm{K_{AB}<25}$) and precise photometric redshifts from the ZFOURGE and UKIDSS surveys as well as grism redshifts from 3DHST. Between 2013--2015 ZFIRE has observed the COSMOS and UDS legacy fields over 13 nights and has obtained 211 galaxy redshifts over $1.57<z<2.66$ from a combination of nebular emission lines (such as \Halpha, \NII, \Hbeta, \OII, \OIII, \SII) observed at 1--2\micron. Based on our medium-band NIR photometry, we are able to spectrophotometrically flux calibrate our spectra to \around10\% accuracy. ZFIRE reaches $5\sigma$ emission line flux limits of \around$\mathrm{3\times10^{-18}~erg/s/cm^2}$ with a resolving power of $R=3500$ and reaches masses down to \around10$^{9}$\msol. We confirm that the primary input survey, ZFOURGE, has produced photometric redshifts for star-forming galaxies (including highly attenuated ones) accurate to $\Delta z/(1+z\mathrm{_{spec})}=0.015$ with $0.7\%$ outliers. We measure a slight redshift bias of $<0.001$, and we note that the redshift bias tends to be larger at higher masses. We also examine the role of redshift on the derivation of rest-frame colours and stellar population parameters from SED fitting techniques. The ZFIRE survey extends spectroscopically-confirmed $z\sim 2$ samples across a richer range of environments, here we make available the first public release of the data for use by the community.\footnote{\url{http://zfire.swinburne.edu.au}}Comment: Published in ApJ. Data available at http://zfire.swinburne.edu.au, Code for figures at https://github.com/themiyan/zfire_survey, 31 pages, 24 figure

ZFOURGE: Extreme 5007A˚\AA emission may be a common early-lifetime phase for star-forming galaxies at z>2.5z > 2.5

Using the \prospector\ spectral energy distribution (SED) fitting code, we analyze the properties of 19 Extreme Emission Line Galaxies (EELGs) identified in the bluest composite SED in the \zfourge\ survey at $2.5 \leq z \leq 4$. \prospector\ includes a physical model for nebular emission and returns probability distributions for stellar mass, stellar metallicity, dust attenuation, and nonparametric star formation history (SFH). The EELGs show evidence for a starburst in the most recent 50 Myr, with the median EELG having a specific star formation rate (sSFR) of 4.6 Gyr$^{-1}$ and forming 15\% of its mass in this short time. For a sample of more typical star-forming galaxies (SFGs) at the same redshifts, the median SFG has a sSFR of 1.1 Gyr$^{-1}$ and forms only $4\%$ of its mass in the last 50 Myr. We find that virtually all of our EELGs have rising SFHs, while most of our SFGs do not. From our analysis, we hypothesize that many, if not most, star-forming galaxies at $z \geq 2.5$ undergo an extreme H$\beta$+[\hbox{{\rm O}\kern 0.1em{\sc iii}}] emission line phase early in their lifetimes. In a companion paper, we obtain spectroscopic confirmation of the EELGs as part of our {\sc MOSEL} survey. In the future, explorations of uncertainties in modeling the UV slope for galaxies at $z>2$ are needed to better constrain their properties, e.g. stellar metallicities.Comment: 11 pages, 5 figures (main figure is fig 5), accepted for publication in Ap

Appropriateness of antibiotic prescribing in the Emergency Department

Background Antibiotics are some of the most commonly prescribed drugs in the Emergency Department (ED) and yet data describing the overall appropriateness of antibiotic prescribing in the ED is scarce. Objectives To describe the appropriateness of antibiotic prescribing in the ED. Methods A retrospective, observational study of current practice. All patients who presented to the ED during the study period and were prescribed at least one antibiotic were included. Specialists from Infectious Disease, Microbiology and Emergency Medicine and a Senior Pharmacist assessed antibiotic appropriateness against evidence-based guidelines. Results A total of 1019 (13.6%) of patient presentations involved the prescription of at least one antibiotic. Of these, 640 (62.8%) antibiotic prescriptions were assessed as appropriate, 333 (32.7%) were assessed as inappropriate and 46 (4.5%) were deemed to be not assessable. Adults were more likely to receive an inappropriate antibiotic prescription than children (36.9% versus 22.9%; difference 14.1%, 95% CI 7.2%–21.0%). Patients who met quick Sepsis-related Organ Failure Assessment (qSOFA) criteria were more likely to be prescribed inappropriate antibiotics (56.7% versus 36.1%; difference 20.5%, 95% CI, 2.4%–38.7%). There was no difference in the incidence of appropriate antibiotic prescribing based on patient gender, disposition (admitted/discharged), reason for antibiotic administration (treatment/prophylaxis) or time of shift (day/night). Conclusions Inappropriate administration of antibiotics can lead to unnecessary adverse events, treatment failure and antimicrobial resistance. With over one in three antibiotic prescriptions in the ED being assessed as inappropriate, there is a pressing need to develop initiatives to improve antibiotic prescribing to prevent antibiotic-associated patient and community harms.No Full Tex