27,563 research outputs found
A Qualitative Study of Asylum Seekers Experience as Mentees with the Welcoming the Stranger Program
Asylum seekers are foreign nationals who enter the United States legally fleeing danger in their home country. Over 26,000 individuals were granted asylum in 2015, with 3.4% of the State of Maine’s population identifying as immigrants. Portland Maine’s General Assistance (GA) office reports nearly 40% of GA recipients were visa holders seeking asylum during fiscal year 2016. Asylum seekers arrive with psychological and physical burdens and then face hurdles trying to gain legal status while attempting to get their basic needs met in the social service systems. Organizations have been created on a grassroots level to provide support and bypass typical systemic obstacles. Welcoming the Stranger (WTS) is one of those organizations in Portland, Maine that matches friends (mentors) with asylum seeking (mentees) to help mitigate any barriers and bridge the gap for these newcomers. Existing research primarily combines asylum seekers and refugees in one category; therefore, more research is needed that focuses on the lived experiences of asylum seekers. This phenomenological study interviewed WTS mentees ages 18 and older and invited participants to create art collages as an additional way to convey their story. A bioecological perspective theoretical framework grounded the research to explore how participation with WTS may mitigate pressure on asylum seekers’ ecosystems. Research on the experiences of WTS mentees, both their challenges and successes, helps inform policy, practice, advocacy and program development
Optimal Estimation of Several Linear Parameters in the Presence of Lorentzian Thermal Noise
In a previous article we developed an approach to the optimal (minimum
variance, unbiased) statistical estimation technique for the equilibrium
displacement of a damped, harmonic oscillator in the presence of thermal noise.
Here, we expand that work to include the optimal estimation of several linear
parameters from a continuous time series. We show that working in the basis of
the thermal driving force both simplifies the calculations and provides
additional insight to why various approximate (not optimal) estimation
techniques perform as they do. To illustrate this point, we compare the
variance in the optimal estimator that we derive for thermal noise with those
of two approximate methods which, like the optimal estimator, suppress the
contribution to the variance that would come from the irrelevant, resonant
motion of the oscillator. We discuss how these methods fare when the dominant
noise process is either white displacement noise or noise with power spectral
density that is inversely proportional to the frequency ( noise). We also
construct, in the basis of the driving force, an estimator that performs well
for a mixture of white noise and thermal noise. To find the optimal
multi-parameter estimators for thermal noise, we derive and illustrate a
generalization of traditional matrix methods for parameter estimation that can
accommodate continuous data. We discuss how this approach may help refine the
design of experiments as they allow an exact, quantitative comparison of the
precision of estimated parameters under various data acquisition and data
analysis strategies.Comment: 16 pages, 10 figures. Accepted for publication in Classical and
Quantum Gravit
Filler bar heating due to stepped tiles in the shuttle orbiter thermal protection system
An analytical study was performed to investigate the excessive heating in the tile to tile gaps of the Shuttle Orbiter Thermal Protection System due to stepped tiles. The excessive heating was evidence by visible discoloration and charring of the filler bar and strain isolation pad that is used in the attachment of tiles to the aluminum substrate. Two tile locations on the Shuttle orbiter were considered, one on the lower surface of the fuselage and one on the lower surface of the wing. The gap heating analysis involved the calculation of external and internal gas pressures and temperatures, internal mass flow rates, and the transient thermal response of the thermal protection system. The results of the analysis are presented for the fuselage and wing location for several step heights. The results of a study to determine the effectiveness of a half height ceramic fiber gap filler in preventing hot gas flow in the tile gaps are also presented
Evaluation of Fast-Time Wake Vortex Prediction Models
Current fast-time wake models are reviewed and three basic types are defined. Predictions from several of the fast-time models are compared. Previous statistical evaluations of the APA-Sarpkaya and D2P fast-time models are discussed. Root Mean Square errors between fast-time model predictions and Lidar wake measurements are examined for a 24 hr period at Denver International Airport. Shortcomings in current methodology for evaluating wake errors are also discussed
Constraining Anisotropic Baryon Oscillations
We present an analysis of anisotropic baryon acoustic oscillations and
elucidate how a mis-estimation of the cosmology, which leads to incorrect
values of the angular diameter distance, d_A, and Hubble parameter, H, manifest
themselves in changes to the monopole and quadrupole power spectrum of biased
tracers of the density field. Previous work has focused on the monopole power
spectrum, and shown that the isotropic "dilation" combination d_A^2/H is
robustly constrained by an overall shift in the scale of the baryon feature. We
extend this by demonstrating that the quadrupole power spectrum is sensitive to
an anisotropic "warping" mode d_A H, allowing one to break the degeneracy
between d_A and H. We describe a method for measuring this warping, explicitly
marginalizing over the form of redshift space distortions. We verify this
method on N-body simulations and estimate that d_A H can be measured with a
fractional accuracy of ~ 3/sqrt(V) % where the survey volume is estimated in
(Gpc/h)^3.Comment: 4 pages, 2 fig
Influence of Potamogeton crispus growth on nutrients in the sediment and water of Lake Tangxunhu
An incubation experiment was performed on Potamogeton crispus (P. crispus) using sediment collected from Lake Tangxunhu in the center of China, in order to determine the effects of plant growth on Fe, Si, Cu, Zn, Mn, Mg, P, and Ca concentrations in the sediments and overlying waters. After 3 months of incubation, Ca, Mg, and Si concentrations in the water column were significantly lower, and P and Cu concentrations were significantly higher than in unplanted controls. The effect of P. crispus growth on sediment pore waters and water-extractable elements varied. Concentrations of Ca, Mg, Si, Fe, Cu, and Zn were significantly higher, and P was significantly lower, than in pore waters of the control. Water-extracted concentrations of Fe, Mg, and Si in the sediments were lower, and P was higher, than in the control. Presence of P. crispus generally enhanced concentration gradients of elements between pore waters and overlying waters but not for P. The growth of P. crispus was associated with an increase in water pH and formation of root plaques, resulting in complex effects on the sediment nutritional status
Specialization of strategies and herding behavior of trading firms in a financial market
The understanding of complex social or economic systems is an important
scientific challenge. Here we present a comprehensive study of the Spanish
Stock Exchange showing that most financial firms trading in that market are
characterized by a resulting strategy and can be classified in groups of firms
with different specialization. Few large firms overally act as trending firms
whereas many heterogeneous firm act as reversing firms. The herding properties
of these two groups are markedly different and consistently observed over a
four-year period of trading.Comment: 8 pages, 5 figure
Non-ancient solution of the Ricci flow
For any complete noncompact Khler manifold with nonnegative and
bounded holomorphic bisectional curvature,we provide the necessary and
sufficient condition for non-ancient solution to the Ricci flow in this paper.Comment: seven pages, latex fil
Economic impact of ventilator-associated pneumonia in a large matched cohort
Objective.To evaluate the economic impact of ventilator-associated pneumonia (VAP) on length of stay and hospital costs.Design.Retrospective matched cohort study.Setting.Premier database of hospitals in the United States.Patients.Eligible patients were admitted to intensive care units (ICUs), received mechanical ventilation for ≥2 calendar-days, and were discharged between October 1, 2008, and December 31, 2009.Methods.VAP was defined by International Classification of Diseases, Ninth Revision (ICD-9), code 997.31 and ventilation charges for ≥2 calendar-days. We matched patients with VAP to patients without VAP by propensity score on the basis of demographics, administrative data, and severity of illness. Cost was based on provider perspective and procedural cost accounting methods.Results.Of 88,689 eligible patients, 2,238 (2.5%) had VAP; the incidence rate was 1.27 per 1,000 ventilation-days. In the matched cohort, patients with VAP (n = 2,144) had longer mean durations of mechanical ventilation (21.8 vs 10.3 days), ICU stay (20.5 vs 11.6 days), and hospitalization (32.6 vs 19.5 days; all P< .0001) than patients without VAP (n = 2,144). Mean hospitalization costs were 59,770 for patients without VAP (P< .0001), resulting in an absolute difference of $39,828. Patients with VAP had a lower in-hospital mortality rate than patients without VAP (482/2,144 [22.5%] vs 630/2,144 [29.4%]; P<.0001).Conclusions.Our findings suggest that VAP continues to occur as defined by the new specific ICD-9 code and is associated with a statistically significant resource utilization burden, which underscores the need for cost-effective interventions to minimize the occurrence of this complication.Infect Control Hosp Epidemiol 2012;33(3):250-256</jats:sec
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