Island Size Selectivity during 2D Ag Island Coarsening on Ag (111)

We report on early stages of submonolayer Ag island coarsening on Ag(111) surface at room temperature ($300$ K) carried out using realistic kinetic Monte Carlo (KMC) simulations. We find that during early stages, coarsening proceeds as a sequence of selected island sizes creating peaks and valleys in the island size distribution. We find that island-size selectivity is due to formation of kinetically stable islands for certain sizes because of adatom detachment/attachment processes and large activation barrier for kink detachment. In addition, we find that the ratio of number of adatom attachment to detachment processes to be independent of parameters of initial configuration and also on the initial shapes of the islands confirming that island-size selectivity is independent of initial conditions.These simulations were carried out using a very large database of processes identified by their local environment and whose activation barriers were calculated using the embedded-atom method

The use of administrative health care databases to identify patients with Rheumatoid Arthritis

Objective: To validate and compare the decision rules to identify rheumatoid arthritis (RA) in administrative databases. Methods: A study was performed using administrative health care data from a population of 1 million people who had access to universal health care. Information was available on hospital discharge abstracts and physician billings. RA cases in health administrative databases were matched 1:4 by age and sex to randomly selected controls without inflammatory arthritis. Seven case definitions were applied to identify RA cases in the health administrative data, and their performance was compared with the diagnosis by a rheumatologist. The validation study was conducted on a sample of individuals with administrative data who received a rheumatologist consultation at the Arthritis Center of Nova Scotia. Results: We identified 535 RA cases and 2,140 non-RA, noninflammatory arthritis controls. Using the rheumatologist's diagnosis as the gold standard, the overall accuracy of the case definitions for RA cases varied between 68.9% and 82.9% with a kappa statistic between 0.26 and 0.53. The sensitivity and specificity varied from 20.7% to 94.8% and 62.5% to 98.5%, respectively. In a reference population of 1 million, the estimated annual number of incident cases of RA was between 176 and 1,610 and the annual number of prevalent cases was between 1,384 and 5,722. Conclusion: The accuracy of case definitions for the identification of RA cases from rheumatology clinics using administrative health care databases is variable when compared to a rheumatologist's assessment. This should be considered when comparing results across studies. This variability may also be used as an advantage in different study designs, depending on the relative importance of sensitivity and specificity for identifying the population of interest to the research question

Parental perceptions of parent-therapist alliance and adolescent self-disclosure on the perceived efficacy of adolescent psychotherapy treatment

This quantitative study explored the impact of parental perceptions of adolescent therapy disclosures on parental perceptions of therapy and therapist. Questions examined were (1) whether parental perceptions of their adolescent\u27s therapy disclosures, parent-reported closeness, and parent-reported warmth differ as a function of adolescent age and parent gender and (2) if parent-therapist alliance ratings, parent-reported closeness, and parent-reported warmth were associated with parental perceptions of treatment efficacy, and if perceived disclosures moderated this association. Participants were 42 parents who had adolescents (ages 12 to 18) who attended outpatient psychotherapy for a minimum of 6 weeks. Demographic information and perceptions of adolescent therapy disclosures, treatment efficacy, therapeutic alliance, closeness, and warmth were reported in an anonymous online survey. Fathers perceived more closeness with older adolescents than younger adolescents. Therapeutic alliance was significantly associated with treatment efficacy for parents of both genders; disclosure moderated this association when therapeutic alliance was low. Findings indicate gender differences in parental perceptions of parent-adolescent relationships, and suggest adolescent disclosures moderate how parents form perceptions of therapy. Findings have implications for how social workers working with adolescents can balance the facilitation of a client\u27s autonomy with the parental involvement that is so crucial to the therapeutic process

Living A Tattooed Life: The Female Experience

Thesis (M.A.) University of Alaska Fairbanks, 2008The present research is rooted in Human Science, and employed the epistemology of Constructionism, as well as the theoretical perspective of Social Construction of Reality. I used Narrative Inquiry as methodology and conversational interviewing as my method of collecting data. I interviewed six women who provided narratives of their lived experience of constructing their identities through tattoos. Three emergent themes, along with three sub-themes, are discussed in regards to the lived experiences of tattooed women: (1) becoming tattooed constructs who you are; (2) becoming tattooed develops relational identity with (a) friends, (b) the tattoo community, (c) family; and (3) the communication of "tattoo remorse" is differentiated from an earlier recognition of tattoo regret. This research provides insight into the lived human experience of tattooed women through their own natural language

A Study of the Management of Opioid Prescriptions Among Patients with a History of Substance Abuse

Prescription opioid abuse is the fastest-growing drug problem in the United States and has been declared an epidemic by the U.S. White House Office of National Drug Control Policy. Immediate release (IR) opioids, especially hydrocodone and oxycodone, are abused or misused most commonly. Dentists are only second to family physicians in the number of IR opioid prescriptions written. Just under ten percent of the population in the United States in 2010 were classified with substance dependence or abuse in 2009. This study poses the following questions: 1. Do patients with a personal or family history of substance abuse manage prescription opioids differently than patients without a personal or family history of substance abuse? 2. Are they more or less likely to lend, borrow, save and/or properly dispose of leftover pills? 3. Do differences exist between their pre­knowledge and post-knowledge of prescription safety behaviors after going through a prescription safety intervention? Opioid analgesics were prescribed to sixty-two consenting adult outpatients treated at the Medical University of South Carolina Post-Doctoral Periodontic program or at the pain management clinic. Participants completed a brief, interactive, patient-tailored, web-based Script Safety intervention, which provided patient education regarding the hazards of prescription opioid misuse, and safe use, storage and disposal of prescription opioids. At one-week and one-month post intervention, participants were contacted via telephone to assess knowledge change and/or retention, medication misuse behaviors, and patient satisfaction. Forty-eight point four percent (N =30) of participants qualified for a positive personal or familial history of addiction. Participants with a positive history of addiction were more likely than chance to lend their prescriptions to other people. These participants were also more likely to borrow pills from other people. Therefore, identification of these patients is essential for the dental community to offer proper counseling and prescribing practices tailored to their individual needs. In doing so, it is likely that fewer drugs will be diverted

Revealing the X-ray source in IRAS 13224-3809 through flux-dependent reverberation lags

IRAS 13224-3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3 - 1 keV) and hard (1.2 - 5 keV) energies. The hard band lags the soft at low frequencies (i.e. hard lag), while the opposite (i.e. soft lag) is observed at high frequencies. In this paper, we study the lag during flaring and quiescent periods. We find that the frequency and absolute amplitude of the soft lag is different during high-flux and low-flux periods. During the low flux intervals, the soft lag is detected at higher frequencies and with smaller amplitude. Assuming that the soft lag is associated with the light travel time between primary and reprocessed emission, this behaviour suggests that the X-ray source is more compact during low-flux intervals, and irradiates smaller radii of the accretion disc (likely because of light bending effects). We continue with an investigation of the lag dependence on energy, and find that isolating the low-flux periods reveals a strong lag signature at the Fe K line energy, similar to results found using 1.3 Ms of data on another well known Narrow-Line Seyfert I galaxy, 1H0707-495.Comment: 6 pages, 8 figures, accepted for publication in MNRA

A comparative study of CO adsorption on flat, stepped and kinked Au surfaces using density functional theory

Our ab initio calculations of CO adsorption energies on low miller index (111), (100), stepped (211), and kinked (532) gold surfaces show a strong dependence on local coordination with a reduction in Au atom coordination leading to higher binding energies. We find trends in adsorption energies to be similar to those reported in experiments and calculations for other metal surfaces. The (532) surface provides insights into these trends because of the availability of a large number of kink sites which naturally have the lowest coordination (6). We also find that, for all surfaces, an increase in CO coverage triggers a decrease in the adsorption energy. Changes in the work-function upon CO adsorption, as well as the frequencies of the CO vibrational modes are calculated, and their coverage dependence is reported.Comment: 18 pages, 4 figure

Concrete Sawing Waste Recycling As Microfiller in Concrete Production

The main idea of the presented work is to find the ways of recycling the sawing waste/sludge in production of the new concrete. The aim of the study is to examine application of the dust-water suspension as micro filler in self-compacting concrete. In the process of sawing concrete elements a lot of dust waste is produced, the average amount being approximately 0.5-1% of the total amount of concrete. To avoid dust pollution in a production plant the sawing process is accompanied by a water stream, as a result, concrete dust as dust-water suspension is stored in special reservoirs. Recycling of such concrete dust suspension and its utilization as a material pose a significant challenge

The changing X-ray time lag in MCG-6-30-15

MCG-6-30-15 is one of the most observed Narrow Line Seyfert 1 galaxies in the X-ray band. In this paper we examine the X-ray time lags in this source using a total of 600 ks in observations (440 ks exposure) taken with the XMM-Newton telescope (300 ks in 2001 and 300 ks in 2013). Both the old and new observations show the usual hard lag that increases with energy, however, the hard lag turns over to a soft lag at frequencies below ~1e-4 Hz. The highest frequencies (~1e-3 Hz) in this source show a clear soft lag, as previously presented for the first 300 ks observation, but no clear iron K lag is detected in either the old or new observation. The soft lag is more significant in the old observation than the new. The observations are consistent with a reverberation interpretation, where the soft, reflected emission is delayed with respect to the hard powerlaw component. These spectral timing results suggest that two distinct variability mechanisms are important in this source: intrinsic coronal variations (which lead to correlated variability in the reprocessed emission), and geometrical changes in the corona. Variability due to geometrical changes does not result in correlated variability in the reflection, and therefore inhibits the clear detection of an iron K lag.Comment: Resubmitted to MNRAS after minor corrections. 11 pages, 10 figure

FPGA-based data partitioning

Implementing parallel operators in multi-core machines often involves a data partitioning step that divides the data into cache-size blocks and arranges them so to allow concurrent threads to process them in parallel. Data partitioning is expensive, in some cases up to 90% of the cost of, e.g., a parallel hash join. In this paper we explore the use of an FPGA to accelerate data partitioning. We do so in the context of new hybrid architectures where the FPGA is located as a co-processor residing on a socket and with coherent access to the same memory as the CPU residing on the other socket. Such an architecture reduces data transfer overheads between the CPU and the FPGA, enabling hybrid operator execution where the partitioning happens on the FPGA and the build and probe phases of a join happen on the CPU. Our experiments demonstrate that FPGA-based partitioning is significantly faster and more robust than CPU-based partitioning. The results open interesting options as FPGAs are gradually integrated tighter with the CPU