570 research outputs found
Hydraulic Fracturing & Water Stress: Growing Competitive Pressures for Water
This Ceres research paper analyzes water use in hydraulic fracturing operations across the United States and the extent to which this activity is taking place in water stressed regions. It provides an overview of efforts underway, such as the use of recycled water and nonfreshwaterresources, to mitigate these impacts and suggests key questions that industry, water managers and investors should be asking. The research is based on well data available at FracFocus.org and water stress indicator maps developed by the World Resources Institute.FracFocus data was collected for more than 25,000 tight oil (sometimes referred to as shaleoil) and shale gas wells in operation from January 2011 through September 2012. The research shows that 65.8 billion gallons of water was used, representing the water use of 2.5 million Americans for a year. Nearly half (47 percent) of the wells were developed in water basinswith high or extremely high water stress. In Colorado, 92 percent of the 3,862 wells were inextremely high water stress areas. In Texas, which accounts for nearly half of the total number of wells analyzed, 5,891 of its 11,634 wells (51 percent) were in high or extremely high waterstress areas. Extremely high water stress means over 80 percent of available water is already being withdrawn for municipal, industrial and agricultural uses.The research paper provides valuable insights about potential water use/water supply conflicts and risks, especially in basins with intense hydraulic fracturing activity and water supply constraints (due to water stress and/or drought). Given projected sharp increases in production in the coming years and the potentially intense nature of local water demands,competition and conflicts over water should be a growing concern for companies, policymakers and investors. Prolonged drought conditions in many parts of Texas and Colorado last summer created increased competition and conflict between farmers, communities and energy developers, which is only likely to continue. In areas such as Colorado and North Dakota,industry has been able to secure water supplies by paying a higher premium for water thanother users or by getting temporary permits. Neither of these practices can be guaranteed to work in the future, however. Even in wetter regions of the northeast United States, dozens of water permits granted to operators had to be withdrawn last summer due to low levels in environmentally vulnerable headwater streams.The bottom line: shale energy development cannot grow without water, but in order to do so the industry's water needs and impacts need to be better understood, measured and managed. A key question investors should be asking is whether water management planning is getting sufficient attention from both industry and regulators
Supporting Novice Teacher Enactments in the Field Class
Teacher preparation programs at NLU are developing practice-centered approaches to teacher education that entail a core set of teaching practices and intentionally designed field-learning opportunities. One addition to prior practice with this approach is the inclusion of a video coaching context where candidates receive feedback from field supervisors on their teaching videos. This study investigated candidate and supervisor perceptions of the feedback in the video coaching context affords in addition to the traditional contexts of face to face field visits and competency appraisal surveys. The findings point to a unique self-regulatory benefit to the video coaching context. They also suggest the need to carefully prepare teacher candidates and field supervisors to effectively utilize each coaching context to ensure they complement one another to best support teacher candidate learning
Evidence for Reduced Specific Star Formation Rates in the Centers of Massive Galaxies at z = 4
We perform the first spatially-resolved stellar population study of galaxies
in the early universe (z = 3.5 - 6.5), utilizing the Hubble Space Telescope
Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS)
imaging dataset over the GOODS-S field. We select a sample of 418 bright and
extended galaxies at z = 3.5 - 6.5 from a parent sample of ~ 8000
photometric-redshift selected galaxies from Finkelstein et al. (2015). We first
examine galaxies at 3.5< z < 4.0 using additional deep K-band survey data from
the HAWK-I UDS and GOODS Survey (HUGS) which covers the 4000A break at these
redshifts. We measure the stellar mass, star formation rate, and dust
extinction for galaxy inner and outer regions via spatially-resolved spectral
energy distribution fitting based on a Markov Chain Monte Carlo algorithm. By
comparing specific star formation rates (sSFRs) between inner and outer parts
of the galaxies we find that the majority of galaxies with the high central
mass densities show evidence for a preferentially lower sSFR in their centers
than in their outer regions, indicative of reduced sSFRs in their central
regions. We also study galaxies at z ~ 5 and 6 (here limited to high spatial
resolution in the rest-frame ultraviolet only), finding that they show sSFRs
which are generally independent of radial distance from the center of the
galaxies. This indicates that stars are formed uniformly at all radii in
massive galaxies at z ~ 5 - 6, contrary to massive galaxies at z < 4.Comment: Accepted to ApJ, 20 pages, 15 figure
CLEAR I: Ages and Metallicities of Quiescent Galaxies at 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 () galaxies selected to have quiescent stellar
populations at . The data include 12--orbit depth coverage with the
WFC3/G102 grism covering ~\AA\, at a spectral
resolution of taken as part of the CANDELS Lyman- Emission
at Reionization (CLEAR) survey. At , 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 ~Gyr,
~Gyr, ~Gyr, and
~Gyr, \editone{for galaxies at , 1.2,
1.3, and 1.6. This} implies that most of the massive quiescent galaxies at
\% of their stellar mass by a redshift of }. The
posteriors give metallicities of \editone{~, ~, ~, and ~}. This is evidence
that massive galaxies had enriched rapidly to approximately Solar metallicities
as early as .Comment: 32 pages, 23 figures, Resubmited to ApJ after revisions in response
to referee repor
Patterns and frequency of anxiety in women undergoing gynaecological surgery
Patterns and frequency of anxiety in women undergoing gynaecological surgery
Aims. Within a gynaecological surgical setting to identify the patterns and frequency
of anxiety pre- and postoperatively; to identify any correlation between raised
anxiety levels and postoperative pain; to identify events, from the patients’ perspective,
that may increase or decrease anxiety in the pre- and postoperative periods.
Background. It is well documented that surgery is associated with increased anxiety,
which has an adverse impact on patient outcomes. Few studies have been conducted
to obtain the patient’s perspective on the experience of anxiety and the events and
situations that aggravate and ameliorate it.
Method. The study used a mixed method approach. The sample consisted of women
undergoing planned gynaecological surgery. Anxiety was assessed using the State
Trait Anxiety Inventory. Trait anxiety was measured at the time of recruitment.
State anxiety was then assessed at six time points during the pre- and postoperative
periods. Postoperative pain was also measured using a 10 cm visual analogue scale.
Taped semi-structured telephone interviews were conducted approximately a week
after discharge.
Results. State anxiety rose steadily from the night before surgery to the point of
leaving the ward to go to theatre. Anxiety then increased sharply prior to the
anaesthetic decreasing sharply afterwards. Patients with higher levels of trait anxiety
were more likely to experience higher levels of anxiety throughout their admission.
Elevated levels of pre- and postoperative anxiety were associated with increased
levels of postoperative pain. Telephone interviews revealed a range of events/situations
that patients recalled distressing them and many were related to inadequate
information.
Conclusion. This study found higher rates of anxiety than previously reported and
anxiety levels appeared raised before admission to hospital. This has important
clinical and research implications.Relevance to clinical practice. Patients with high levels of anxiety may be identified
preoperatively and interventions designed to reduce anxiety could be targeted to this
vulnerable group. Patient experiences can inform the delivery of services to meet
their health needs better
The distribution of satellites around massive galaxies at 1<z<3 in ZFOURGE/CANDELS: dependence on star formation activity
We study the statistical distribution of satellites around star-forming and
quiescent central galaxies at 1<z<3 using imaging from the FourStar Galaxy
Evolution Survey (ZFOURGE) and the Cosmic Assembly Near-IR Deep Extragalactic
Legacy Survey (CANDELS). The deep near-IR data select satellites down to
at z<3. The radial satellite distribution around centrals
is consistent with a projected NFW profile. Massive quiescent centrals,
, have 2 times the number of satellites compared
to star-forming centrals with a significance of 2.7 even after
accounting for differences in the centrals' stellar-mass distributions. We find
no statistical difference in the satellite distributions of intermediate-mass
quiescent and star-forming centrals, . Comparing
to the Guo2011 semi-analytic model, the excess number of satellites indicates
that quiescent centrals have halo masses 0.3 dex larger than star-forming
centrals, even when the stellar-mass distributions are fixed. We use a simple
toy model that relates halo mass and quenching, which roughly reproduces the
observed quenched fractions and the differences in halo mass between
star-forming and quenched galaxies only if galaxies have a quenching
probability that increases with halo mass from 0 for
11 to 1 for 13.5. A single
halo-mass quenching threshold is unable to reproduce the quiescent fraction and
satellite distribution of centrals. Therefore, while halo quenching may be an
important mechanism, it is unlikely to be the only factor driving quenching. It
remains unclear why a high fraction of centrals remain star-forming even in
relatively massive halos.Comment: 19 pages, 17 figures, accepted by ApJ. Information on ZFOURGE can be
found at http://zfourge.tamu.ed
The value of different aspects of person-centred care: a series of discrete choice experiments in people with long-term conditions
Objective: To measure the value the patients place on different aspects of person-centred care.
Design: We systematically identified four attributes of person-centred care. We then measured their value to 923 people with either chronic pain or chronic lung disease over three discrete choice experiments (DCEs) about services to support self-management. We calculated the value of each attribute for all respondents and identified groups of people with similar preferences using latent class modelling.
Setting: DCEs conducted online via a commercial survey company.
Participants: Adults with either chronic pain (two DCEs, n=517 and 206, respectively) or breathlessness due to chronic respiratory disease (n=200).
Results: Participants were more likely to choose services with higher level person-centred attributes. They most valued services that took account of a person’s current situation likelihood of selection increased by 16.9% (95% CI=15.4 to 18.3) and worked with the person on what they wanted to get from life (15.8%; 14.5 to 17.1). More personally relevant information was valued less than these (12.3%; 11.0 to 13.6). A friendly and personal communicative style was valued least (3.8%; 2.7 to 4.8). Latent class models indicated that a substantial minority of participants valued personally relevant information over the other attributes.
Conclusion: This is the first study to measure the value patients place on different aspects of person-centred care. Professional training needs to emphasise the substance of clinical communication—working responsively with individuals on what matters to them—as well as the style of its delivery
RELICS: The Reionization Lensing Cluster Survey and the Brightest High-z Galaxies
Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here the z ~ 6-8 candidate high-redshift galaxies from the Reionization Lensing Cluster Survey (RELICS), a Hubble and Spitzer Space Telescope survey of 41 massive galaxy clusters spanning an area of ≈200 arcmin². These clusters were selected to be excellent lenses, and we find similar high-redshift sample sizes and magnitude distributions as the Cluster Lensing And Supernova survey with Hubble (CLASH). We discover 257, 57, and eight candidate galaxies at z ~ 6, 7, and 8 respectively, (322 in total). The observed (lensed) magnitudes of the z ~ 6 candidates are as bright as AB mag ~23, making them among the brightest known at these redshifts, comparable with discoveries from much wider, blank-field surveys. RELICS demonstrates the efficiency of using strong gravitational lenses to produce high-redshift samples in the epoch of reionization. These brightly observed galaxies are excellent targets for follow-up study with current and future observatories, including the James Webb Space Telescope
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