No Pulsar Left Behind. I. Timing, Pulse-sequence Polarimetry, and Emission Morphology for 12 pulsars

In this paper we study a set of twelve pulsars that previously had not been characterized. Our timing shows that eleven of them are "normal" isolated pulsars, with rotation periods between 0.22 and 2.65 s, characteristic ages between 0.25 Myr and 0.63 Gyr, and estimated magnetic fields ranging from 0.05 to 3.8x 10^{12} G. The youngest pulsar in our sample, PSR~J0627+0706, is located near the Monoceros supernova remnant (SNR G205.5+0.5), but it is not the pulsar most likely to be associated with it. We also confirmed the existence of a candidate from an early Arecibo survey, PSR~J2053+1718, its subsequent timing and polarimetry are also presented here. It is an isolated pulsar with a spin period of 119 ms, a relatively small magnetic field of 5.8x10^9 G and a characteristic age of 6.7 Gyr; this suggests the pulsar was mildly recycled by accretion from a companion star which became unbound when that companion became a supernova. We report the results of single-pulse and average Arecibo polarimetry at both 327 and 1400 MHz aimed at understanding the basic emission properties and beaming geometry of these pulsars. Three of them (PSRs~J0943+2253, J1935+1159 and J2050+1259) have strong nulls and sporadic radio emission, several others exhibit interpulses (PSRs J0627+0706 and J0927+2345) and one shows regular drifting subpulses (J1404+1159).Comment: 17 pages, 14 figure

Improving Low-Cost Measurement Techniques to Investigate the Connections Between Fossil Fuels and Air Quality: from Oil and Gas Production to Home Heating

Natural gas, as an energy resource can exert both positive and negative influences on air quality where people live, work, and go to school. Air quality in basins where oil and gas are produced from geologic formations can be potentially degraded by industry activities, but using natural gas in place of solid fuels like wood and coal for home heating and in other applications can potentially result in improved air quality. Low- cost gas sensors have emerged recently with great potential to help inform air quality on the scales that people live in ways that traditional instrumentation is not well suited, though the usefulness of these tools is complicated by cross sensitivity to environmental variables like temperature and humidity, as well as potentially confounding gas species. The ability of low-cost gas sensors to yield meaningful information about air quality, with relevance to human and environmental health, is therefore contingent on progress in terms of sensor signal quantification methods, best practices for experimental design and deployment, along with data quality assessment and interpretation.In this dissertation, such methods are developed and applied, employing low-cost gas sensors to characterize air quality in both indoor and ambient environments, in the context of natural gas production and end use as a home heating fuel. Carbon monoxide (CO) measurements are used to characterize how home heating fuels can differentially influence air quality in homes on the Navajo Nation. CO levels in homes are quantified with uncertainty estimation and are employed to estimate air exchange rates in homes and CO emission rates. Methods to measure air quality in oil and gas production basins using arrays of low-cost gas sensors are also developed and analyzed. Field normalization sensor signal quantification methods employing both artificial neural networks and multiple linear regressions are compared. The sensitivity and robustness of each quantification method is explored for each gas species. To further understand how distributed grids of sensor measurements can inform spatial and temporal patterns of air quality in oil and gas production basins, the performance of these sensor quantification methods are assessed when extended to new sampling locations

Dynamic localization of yeast Fus2p to an expanding ring at the cell fusion junction during mating

Fus2p is a pheromone-induced protein associated with the amphiphysin homologue Rvs161p, which is required for cell fusion during mating in Saccharomyces cerevisiae. We constructed a functional Fus2p–green fluorescent protein (GFP), which exhibits highly dynamic localization patterns in pheromone-responding cells (shmoos): diffuse nuclear, mobile cytoplasmic dots and stable cortical patches concentrated at the shmoo tip. In mitotic cells, Fus2p-GFP is nuclear but becomes cytoplasmic as cells form shmoos, dependent on the Fus3p protein kinase and high levels of pheromone signaling. The rapid cytoplasmic movement of Fus2p-GFP dots requires Rvs161p and polymerized actin and is aberrant in mutants with compromised actin organization, which suggests that the Fus2p dots are transported along actin cables, possibly in association with vesicles. Maintenance of Fus2p-GFP patches at the shmoo tip cortex is jointly dependent on actin and a membrane protein, Fus1p, which suggests that Fus1p is an anchor for Fus2p. In zygotes, Fus2p-GFP forms a dilating ring at the cell junction, returning to the nucleus at the completion of cell fusion

Controlled Postpartum-Newborn Simulation With Objective Evaluation Exchanged for Clinical Learning

Background: Simulation is a widely used teaching strategy. A paucity of evidence exist about evaluating acquisition of formal knowledge gained from simulation participation. This study compared practicing simulated assessments in the CSLC to practice in the clinical setting plus simulation, high/low level of student performance, and evaluated performance. Study variables were assessment, intervention, and critical thinking. Methods: Non-equivalent comparison group, post-test only quasi-experimental. 80 undergraduate nursing students individually demonstrated assessments while trained observer scored performance. Students provided written response to 7 questions before debriefing. T-tests, ANOVA, and MANOVA compared scores between the two groups. An outlier analysis operationalized high /low student performance. 92 points on both simulations equated to competent performance; lower scores required remediation. Results: No significant differences between the two groups on three study variables. A significant correlation found between postpartum and newborn psychomotor skills in high and low performing students. Average simulation performance score was 83 points. Conclusion: Well-designed simulation can be exchanged for learning in clinical, identify underperforming students, and evaluate performance qualit

Recurrent Perineal Hernia After Benign Pelvic Reconstructive Surgery

Abstract Background: Secondary acquired perineal hernias are rare events usually associated with extensive pelvic surgery. Although most are asymptomatic, when symptoms are present surgical intervention is warranted. There is currently no consensus regarding the management of these hernias. An unusual case of a recurrent perineal hernia following sacrospinous fixation resulting in large bowel incarceration is reported. Case: A 64-year-old woman presented with an anterior vaginal wall prolapse and multiple pelvic-floor defects. She subsequently underwent a sacrospinous fixation and enterocele repair. The enterocele recurred and she underwent a second enterocele repair. Approximately 6 months later, she presented with a perineal hernia that involved an incarceration of the large bowel. Results: The hernia was reduced, the pelvic-floor defect was repaired, and a biologic, absorbable mesh was applied. Approximately 5 months later, the patient presented with a recurrence of the perineal hernia. The hernia was reduced and this time a synthetic, nonabsorbable mesh was used, and there were no signs of recurrence at 6 months' follow-up. Conclusions: Acquired perineal hernias are extremely rare events, especially when they recur and involve large bowel incarceration. Several factors may influence the development and possible recurrence of secondary acquired perineal hernias, including lifestyle, occupation, gestational history, and past medical and surgical history. The use of a nonabsorbable mesh to prevent recurrence is suggested, although current literature reports success rates that are fairly similar for users of both absorbable and nonabsorbable meshes. (J GYNECOL SURG 28:230)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98451/1/gyn%2E2011%2E0051.pd

CLEAR II: Evidence for Early Formation of the Most Compact Quiescent Galaxies at High Redshift

The origin of the correlations between mass, morphology, quenched fraction, and formation history in galaxies is difficult to define, primarily due to the uncertainties in galaxy star-formation histories. Star-formation histories are better constrained for higher redshift galaxies, observed closer to their formation and quenching epochs. Here we use "non-parametric" star-formation histories and a nested sampling method to derive constraints on the formation and quenching timescales of quiescent galaxies at $0.7<z<2.5$. We model deep HST grism spectroscopy and photometry from the CLEAR (CANDELS Lyman$-\alpha$ Emission at Reionization) survey. The galaxy formation redshifts, $z_{50}$ (defined as the point where they had formed 50\% of their stellar mass) range from $z_{50}\sim 2$ (shortly prior to the observed epoch) up to $z_{50} \simeq 5-8$. \editone{We find that early formation redshifts are correlated with high stellar-mass surface densities, $\log \Sigma_1 / (M_\odot\ \mathrm{kpc}^{-2}) >$10.25, where $\Sigma_1$ is the stellar mass within 1~pkpc (proper kpc). Quiescent galaxies with the highest stellar-mass surface density, $\log\Sigma_1 / (M_\odot\ \mathrm{kpc}^{-2}) > 10.25$, } show a \textit{minimum} formation redshift: all such objects in our sample have $z_{50} > 2.9$. Quiescent galaxies with lower surface density, $\log \Sigma_1 / (M_\odot\ \mathrm{kpc}^{-2}) = 9.5 - 10.25$, show a range of formation epochs ($z_{50} \simeq 1.5 - 8$), implying these galaxies experienced a range of formation and assembly histories. We argue that the surface density threshold$\log\Sigma_1/(M_\odot\ \mathrm{kpc}^{-2})>10.25$ uniquely identifies galaxies that formed in the first few Gyr after the Big Bang, and we discuss the implications this has for galaxy formation models.Comment: 13 pages, 7 figures, accepted for publication in ApJ. Includes an interactive online appendix (https://vince-ec.github.io/appendix/appendix

CLEAR I: Ages and Metallicities of Quiescent Galaxies at 1.0<z<1.8\mathbf{1.0 < z < 1.8} Derived from Deep Hubble Space Telescope Grism Data

We use deep \textit{Hubble Space Telescope} spectroscopy to constrain the metallicities and (\editone{light-weighted}) ages of massive ($\log M_\ast/M_\odot\gtrsim10$) galaxies selected to have quiescent stellar populations at $1.0<z<1.8$. The data include 12--orbit depth coverage with the WFC3/G102 grism covering $\sim$ $8,000<\lambda<11,500$~\AA\, at a spectral resolution of $R\sim 210$ taken as part of the CANDELS Lyman-$\alpha$ Emission at Reionization (CLEAR) survey. At $1.0<z<1.8$, the spectra cover important stellar population features in the rest-frame optical. We simulate a suite of stellar population models at the grism resolution, fit these to the data for each galaxy, and derive posterior likelihood distributions for metallicity and age. We stack the posteriors for subgroups of galaxies in different redshift ranges that include different combinations of stellar absorption features. Our results give \editone{light-weighted ages of $t_{z \sim 1.1}= 3.2\pm 0.7$~Gyr, $t_{z \sim 1.2}= 2.2\pm 0.6$~Gyr, $t_{z\sim1.3}= 3.1\pm 0.6$~Gyr, and $t_{z\sim1.6}= 2.0 \pm 0.6$~Gyr, \editone{for galaxies at $z\sim 1.1$, 1.2, 1.3, and 1.6. This} implies that most of the massive quiescent galaxies at $168$\% of their stellar mass by a redshift of $z>2$}. The posteriors give metallicities of \editone{$Z_{z\sim1.1}=1.16 \pm 0.29$~$Z_\odot$, $Z_{z\sim1.2}=1.05 \pm 0.34$~$Z_\odot$, $Z_{z\sim1.3}=1.00 \pm 0.31$~$Z_\odot$, and $Z_{z\sim1.6}=0.95 \pm 0.39$~$Z_\odot$}. This is evidence that massive galaxies had enriched rapidly to approximately Solar metallicities as early as $z\sim3$.Comment: 32 pages, 23 figures, Resubmited to ApJ after revisions in response to referee repor

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

To cool a high mobility two-dimensional electron gas (2DEG) at a GaAs-AlGaAs heterojunction to milliKelvin temperatures, we have fabricated low resistance Ohmic contacts based on alloys of Au, Ni, and Ge. The Ohmic contacts have a typical contact resistance of R C ≈ 0.8 ω at 4.2 K, which drops to 0.2 ω below 0.9 K. Scanning electron microscope images establish that the contacts have the same inhomogeneous microstructure that has been observed in previous studies. Measurements of the contact resistance R C, the four-terminal resistance along the top of a single contact, and the vertical resistance RV all show that there is a superconductor in the Ohmic contact, which can be turned completely normal with a magnetic field of 0.15 T. We briefly discuss how this superconductivity may be affecting the electrical transport measurements of 2DEGs, especially how it may hinder the cooling of electrons in a 2DEG below 0.1 K

CLEAR: Spatially Resolved Emission Lines and Active Galactic Nuclei at 0.6<z<1.30.6<z<1.3

We investigate spatially-resolved emission-line ratios in a sample of 219 galaxies ($0.6<z<1.3$) detected using the G102 grism on the \emph{Hubble Space Telescope} Wide Field Camera 3, taken as part of the CANDELS Ly$\alpha$ Emission at Reionization (CLEAR) survey, to measure ionization profiles and search for low-luminosity active galactic nuclei (AGN). We analyze \OIII\ and \Hb\ emission-line maps, enabling us to spatially resolve the \OIIIHb\ emission-line ratio across the galaxies in the sample. We compare the \OIIIHb\ ratio in galaxy centers and outer annular regions to measure ionization gradients and investigate the potential of sources with nuclear ionization to host AGN. We investigate some of the individual galaxies that are candidates to host strong nuclear ionization and find that they often have low stellar mass and are undetected in X-rays, as expected for low-luminosity AGN in low-mass galaxies. We do not find evidence for a significant population of off-nuclear AGN or other clumps of off-nuclear ionization. We model the observed distribution of \OIIIHb\ gradients and find that most galaxies are consistent with small or zero gradients, but 6-16\% of galaxies in the sample are likely to host nuclear \OIIIHb\ that is $\sim$0.5~dex higher than in their outer regions. This study is limited by large uncertainties in most of the measured \OIIIHb\ spatial profiles, therefore deeper data, e.g, from deeper \textit{HST}/WFC3 programs or from \textit{JWST}/NIRISS, are needed to more reliably measure the spatially resolved emission-line conditions of individual high-redshift galaxies.Comment: 16 pages, 13 figures, 2 table