Near-Infrared Integral Field Spectroscopy of Damped Lyman-alpha Systems

We assess the feasibility of detecting star formation in damped Lyman-alpha systems (DLAs) at z>1 through near-infrared spectroscopy using the forthcoming integral field units on 8m-class telescopes. Although their relation to galaxies is not well established, high-z DLAs contain most of the neutral gas in the Universe, and this reservoir is depleted with time - presumably through star formation. Line emission should be an indicator of star formation activity, but searches based on Lyman-alpha are unreliable because of the selective extinction of this resonant UV line. Using more robust lines such as H-alpha forces a move to the near-infrared at z>1. For line emission searches, spectroscopy is more sensitive than imaging, but previous long-slit spectroscopic searches have been hampered by the likelihood that any star forming region in the DLA galaxy disk would fall outside the narrow slit. The new integral field units such as CIRPASS on Gemini will cover sufficient solid angles to intercept these, even in the extreme case of large galactic disks at high redshift. On an 8m-class telescope, star formation rates of <1M_sun/yr will be reached at z~1.4 with H-alpha in the H-band. Such star formation rates are well below L* for the high-z Lyman-break population, and are comparable locally to the luminous giant HII complexes in M101. It appears that instruments such as CIRPASS on Gemini will have both the sensitivity and the survey area to measure star formation rates in z>1 DLAs. These observations will probe the nature of damped Lyman-alpha systems and address their relation to galaxies.Comment: To appear in the proceedings of the ESO/ECF workshop on "Deep Fields", 9-12 October 2000, Garching. 4 page

Peace with strength : developing the conditions of coercive diplomacy

United States policymakers need viable crisis response options – other than war – when deterrence is not able to prevent aggression. This study examines one policy option in the space between deterrence and war: coercive diplomacy. Applied successfully, coercive diplomacy defuses emerging conflicts by persuading an aggressor to change or reverse their behavior. However, attempts at coercive diplomacy fail more often than they succeed, even when applied by global powers like the United States. I build on the work of scholars who have examined policy traits found within effective coercive diplomacy attempts. Alexander George first developed a set of conditions for coercive diplomacy – also described as ingredients or prerequisites – that, when present, increase the policy’s likelihood of success. A critical gap in the literature is a study that helps understand what leads to creating the conditions for coercive diplomacy – or what stands in the way of establishing those conditions. The central research question for this study is what facilitates or inhibits U.S. policymakers from developing favorable conditions for coercive diplomacy? I examine historical cases from the Johnson, Reagan, and Clinton administrations where the United States attempted coercive diplomacy to reveal the messy realities of policymaking. I uncover the complicated relationships, impediments to action, and what subtle factors helped U.S. decision-makers develop policies to compel opponents to change behavior. This research helps establish how policymakers achieve the conditions of coercive diplomacy or what factors prevent them from attaining these benchmarks. The conclusion of this dissertation provides original insights about the eight conditions, both individually and how they interact with one another. Learning how the conditions interact is one of the novel and important contributions of my dissertation to the field of coercion. Understanding how the conditions interact also helps policymakers anticipate the dynamics or tensions between the different conditions. I share seven policy implications that this study reveals about future applications of coercive diplomacy. Lastly, I offer a series of initial questions that policymakers should ask before exercising coercive diplomacy.Public Polic

Management of irrigation maintenance

Management of irrigation maintenanc

Associations between mixtures of urinary phthalate metabolites with gestational age at delivery: a time to event analysis using summative phthalate risk scores

Abstract Background Preterm birth is a significant public health concern and exposure to phthalates has been shown to be associated with an increased odds of preterm birth. Even modest reductions in gestational age at delivery could entail morbid consequences for the neonate and analyzing data with this additional information may be useful. In the present analysis, we consider gestational age at delivery as our outcome of interest and examine associations with multiple phthalates. Methods Women were recruited early in pregnancy as part of a prospective, longitudinal birth cohort at the Brigham and Women’s Hospital in Boston, Massachusetts. Urine samples were collected at up to four time points during gestation for urinary phthalate metabolite measurement, and birth outcomes were recorded at delivery. From this population, we selected all 130 cases of preterm birth (< 37 weeks of gestation) as well as 352 random controls. We conducted analysis with both geometric average of the exposure concentrations across the first three visits as well as using repeated measures of the exposure. Two different time to event models were used to examine associations between nine urinary phthalate metabolite concentrations and time to delivery. Two different approaches to constructing a summative phthalate risk score were also considered. Results The single-pollutant analysis using a Cox proportional hazards model showed the strongest association with a hazard ratio (HR) of 1.21 (95% confidence interval (CI): 1.09, 1.33) per interquartile range (IQR) change in average log-transformed mono-2-ethyl-5-carboxypentyl phthalate (MECPP) concentration. Using the accelerated failure time model, we observed a 1.19% (95% CI: 0.26, 2.11%) decrease in gestational age in association with an IQR change in average log-transformed MECPP. We next examined associations with an environmental risk score (ERS). The fourth quartile of ERS was significantly associated with a HR of 1.44 (95% CI: 1.19, 1.75) and a reduction of 2.55% (95% CI: 0.76, 4.30%) in time to delivery (in days) compared to the first quartile. Conclusions On average, pregnant women with higher urinary metabolite concentrations of individual phthalates have shorter time to delivery. The strength of the observed associations are amplified with the risk scores when compared to individual pollutants.https://deepblue.lib.umich.edu/bitstream/2027.42/144517/1/12940_2018_Article_400.pd

WFPC2 Observations of the Hubble Deep Field-South

The Hubble Deep Field-South observations targeted a high-galactic-latitude field near QSO J2233-606. We present WFPC2 observations of the field in four wide bandpasses centered at roughly 300, 450, 606, and 814 nm. Observations, data reduction procedures, and noise properties of the final images are discussed in detail. A catalog of sources is presented, and the number counts and color distributions of the galaxies are compared to a new catalog of the HDF-N that has been constructed in an identical manner. The two fields are qualitatively similar, with the galaxy number counts for the two fields agreeing to within 20%. The HDF-S has more candidate Lyman-break galaxies at z > 2 than the HDF-N. The star-formation rate per unit volume computed from the HDF-S, based on the UV luminosity of high-redshift candidates, is a factor of 1.9 higher than from the HDF-N at z ~ 2.7, and a factor of 1.3 higher at z ~ 4.Comment: 93 pages, 25 figures; contains very long table

Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation

BACKGROUND: Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient’s limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated. METHODS: A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/−50 N) and torque (+/− 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles. RESULTS: There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen. CONCLUSIONS: In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness

Biomechanical comparison of different external fixation configurations for posttraumatic pelvic ring instability

Background. External fixation is useful in the primary treatment of pelvic ring injuries. The present study compared the biomechanical stability of five different configurations of an external pelvic ring fixation system. Methods. Five configurations of an anterior external pelvic ring fixation system were tested using a universal testing machine. One single connecting rod was used in group “SINGLE,” two parallel connecting rods in group “DOUBLE,” two and four rods, respectively, in a tent-like configuration in groups “SINGLE TENT” and “DOUBLE TENT,” and a rhomboid-like configuration in group “RHOMBOID.” Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz lateral compression/distraction (±50 N) and torque (±0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700, and 900 cycles. Results. The “SINGLE TENT” and “RHOMBOID” configurations already failed with a preloading of 50 N compression force. The “DOUBLE” configuration had around twice the translational stability compared with the “SINGLE” and “DOUBLE TENT” configurations. Rotational stiffness observed for the “DOUBLE” and “DOUBLE TENT” configurations was about 50% higher compared to the SINGLE configuration. Conclusion. Using two parallel connecting rods provides the highest translational and rotational stability

Mayawaves: Python Library for Interacting with the Einstein Toolkit and the MAYA Catalog

Numerical relativity simulations are crucial for studying black holes and have been instrumental in the detection of gravitational waves by the LVK. However, these simulations produce vast amounts of data that must be processed in order to perform studies, create models, and use them with gravitational wave detection pipelines. This paper introduces mayawaves, an open-source python library for processing, studying, and exporting numerical relativity simulations performed using the Einstein Toolkit and MAYA. Mayawaves streamlines the process of analyzing simulations with an intuitive interface, greatly reducing the learning curve for numerical relativity.Comment: 2 page