6,243 research outputs found
Profit Persistence and Stock Returns
This paper attempts to assemble further empirical evidence on the relationship between the product and the financial market. Drawing back on work in industrial organization, we analyse the relationship between profit persistence and factor adjusted stock returns looking at about 2000 listed US firms over the last 34 years. While the relationship between (current, lagged and unexpected) profits/earnings and returns has been extensively analysed before, to our knowledge this is the first study to look at the relationship between stock returns and profit persistence. We interpret profit persistence as a result of market competition and innovation of the firm. It is shown that firm specific long-run profit persistence after correction for other additional economic fundamentals of the firm have a positive impact on 4-factor adjusted returns and a negative impact on their volatility
No dependence of radio properties of brightest group galaxies on the luminosity gap
We study the radio and optical properties of the brightest group galaxies
(BGGs) in a sample of galaxy groups from the SDSS DR7. The luminosity
difference between the BGG and the second ranked galaxy in the group (known as
the luminosity, or magnitude, gap) has been used as a probe for the level of
galaxy interaction for the BGG within the group. We study the properties of
BGGs with magnitude gaps in the range 0-2.7 magnitudes, in order to investigate
any relation between luminosity gap and the radio properties of the BGG. In
order to eliminate selection biases, we ensure that all variations in stellar
mass are accounted for. We then confirm that, at fixed stellar mass, there are
no significant variations in the optical properties of the BGGs over the full
range of luminosity gaps studied. We compare these optical results with the
EAGLE hydrodynamical simulations and find broad consistency with the
observational data. Using EAGLE we also confirm that no trends begin to arise
in the simulated data at luminosity gaps beyond our observational limits.
Finally, we find that, at fixed stellar mass, the fraction of BGGs that are
radio-loud also shows no trends as a function of luminosity gap. We examine how
the BGG offset from the center of group may affect the radio results and find
no significant trend for the fraction of radio-loud BGGs with magnitude gap in
either the BGG samples with greater or less than 100kpc offset from the center
of group.Comment: Accepted for publication in A
Teleportation-based number state manipulation with number sum measurement
We examine various manipulations of photon number states which can be
implemented by teleportation technique with number sum measurement. The
preparations of the Einstein-Podolsky-Rosen resources as well as the number sum
measurement resulting in projection to certain Bell state may be done
conditionally with linear optical elements, i.e., beam splitters, phase
shifters and zero-one-photon detectors. Squeezed vacuum states are used as
primary entanglement resource, while single-photon sources are not required.Comment: 9 pages, 4 figures, Misprints are corrected. 3 figures for number sum
measurement are added. Discussion on manipulations are expanded. Calculations
for success probabilities are added. Fig.4 is adde
A multicentre integration of a computer-led follow-up of prostate cancer is valid and safe
Background
Prostate cancer (CaP) has a rising number of patients requiring routine follow up. In this study, we aimed to test a computer led follow up service for prostate cancer in two UK hospitals. The testing aimed to validate the computer Expert system in making clinical decisions according to the individual patient’s clinical need. The valid model should accurately identify patients with disease recurrence or treatment failure based on their blood test and clinical picture.
Methods
A clinical decision support system (CDSS) was developed from European (EAU) and national (NICE) guidelines along with knowledge acquired from Urologists. This model was then applied in two UK hospitals to review patients post CaP treatment. These patients’ data (n= 200) were then reviewed by two independent Urology consultants (blinded from the CDSS and other consultant’s rating) and the agreement was calculated by kappa statistics for validation. The second objective aimed to verify the system by estimating the system reliability.
Results
The two individual urology consultants identified 12 % & 15% of the patients to have potential disease progression and recommended their referral to the Urology care. The kappa coefficient for the agreement between the CDSS and the 2 consultants was 0.81 (p < 0.001) and 0.84 (p < 0.001). The agreement among both specialist was also high with k = 0.83 (p < 0.001). The system reliability was estimated on all cases and this demonstrated 100% repeatability of the decisions.
Conclusion
The computer led follow up is a valid model for providing safe follow up for prostate cancer
Individual and group based parenting programmes for improving psychosocial outcomes for teenage parents and their children.
BACKGROUND: Parenting programmes are a potentially important means of supporting teenage parents and improving outcomes for their children, and parenting support is a priority across most Western countries. This review updates the previous version published in 2001. OBJECTIVES: To examine the effectiveness of parenting programmes in improving psychosocial outcomes for teenage parents and developmental outcomes in their children. SEARCH STRATEGY: We searched to find new studies for this updated review in January 2008 and May 2010 in CENTRAL, MEDLINE, EMBASE, ASSIA, CINAHL, DARE, ERIC, PsycINFO, Sociological Abstracts and Social Science Citation Index. The National Research Register (NRR) was last searched in May 2005 and UK Clinical Research Network Portfolio Database in May 2010. SELECTION CRITERIA: Randomised controlled trials assessing short-term parenting interventions aimed specifically at teenage parents and a control group (no-treatment, waiting list or treatment-as-usual). DATA COLLECTION AND ANALYSIS: We assessed the risk of bias in each study. We standardised the treatment effect for each outcome in each study by dividing the mean difference in post-intervention scores between the intervention and control groups by the pooled standard deviation. MAIN RESULTS: We included eight studies with 513 participants, providing a total of 47 comparisons of outcome between intervention and control conditions. Nineteen comparisons were statistically significant, all favouring the intervention group. We conducted nine meta-analyses using data from four studies in total (each meta-analysis included data from two studies). Four meta-analyses showed statistically significant findings favouring the intervention group for the following outcomes: parent responsiveness to the child post-intervention (SMD -0.91, 95% CI -1.52 to -0.30, P = 0.04); infant responsiveness to mother at follow-up (SMD -0.65, 95% CI -1.25 to -0.06, P = 0.03); and an overall measure of parent-child interactions post-intervention (SMD -0.71, 95% CI -1.31 to -0.11, P = 0.02), and at follow-up (SMD -0.90, 95% CI -1.51 to -0.30, P = 0.004). The results of the remaining five meta-analyses were inconclusive. AUTHORS' CONCLUSIONS: Variation in the measures used, the included populations and interventions, and the risk of bias within the included studies limit the conclusions that can be reached. The findings provide some evidence to suggest that parenting programmes may be effective in improving a number of aspects of parent-child interaction both in the short- and long-term, but further research is now needed
Impact of student choice on academic performance:cross-sectional and longitudinal observations of a student cohort
BACKGROUND: Student choice plays a prominent role in the undergraduate curriculum in many contemporary medical schools. A key unanswered question relates to its impact on academic performance. METHODS: We studied 301 students who were in years 2 and 3 of their medical studies in 2005/06. We investigated the relationship between SSC grade and allocated preference. Separately, we examined the impact of ‘self-proposing’ (students designing and completing their own SSC) on academic performance in other, standard-set, summative assessments throughout the curriculum. The chi-squared test was used to compare academic performance in SSC according to allocated preference. Generalised estimating equations were used to investigate the effect of self-proposing on performance in standard-set examinations. RESULTS: (1) Performance in staff-designed SSC was not related to allocated preference. (2) Performance in year 1 main examination was one of the key predictors of performance in written and OSCE examinations in years 2, 3 and 4 (p<0.001). (3) The higher the score in the year 1 examination, the more likely a student was to self-propose in subsequent years (OR [CI] 1.07 [1.03-1.11], p<0.001). (4) Academic performance of students who self-proposed at least once in years 2 and/or 3 varied according to gender and year of course. CONCLUSION: In this study, no association was observed between allocated preference and SSC grade. The effect of self-proposing on academic performance in standard-set examinations was small. Our findings suggest instead that academically brighter students are more likely to design their own modules. Although student choice may have educational benefits, this report does not provide convincing evidence that it improves academic performance
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Asymptotics for Panel Models with Common Shocks
This article develops a novel asymptotic theory for panel models with common shocks. We assume that contemporaneous correlation can be generated by both the presence of common regressors among units and weak spatial dependence among the error terms. Several characteristics of the panel are considered: cross-sectional and time-series dimensions can either be fixed or large; factors can either be observable or unobservable; the factor model can describe either a cointegration relationship or a spurious regression, and we also consider the stationary case. We derive the rate of convergence and the limit distributions for the ordinary least square (OLS) estimates of the model parameters under all the aforementioned cases
Macroscopically distinct quantum superposition states as a bosonic code for amplitude damping
We show how macroscopically distinct quantum superposition states
(Schroedinger cat states) may be used as logical qubit encodings for the
correction of spontaneous emission errors. Spontaneous emission causes a bit
flip error which is easily corrected by a standard error correction circuit.
The method works arbitrarily well as the distance between the amplitudes of the
superposed coherent states increases.Comment: 4 pages, 2 postscript figures, LaTeX2e, RevTeX, minor changes, 1
reference adde
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