7,027 research outputs found
Are There Thresholds of Current Account Adjustment in the G7?
We find evidence of threshold behavior in current account adjustment for the G7 countries, such that the dynamics of adjustment towards equilibrium depend upon whether the current-account/ net-output ratio breaches estimated, country specific current account surplus or deficit thresholds. Both the speeds of adjustment and the size of the thresholds are found to differ significantly across countries. In addition, we also find evidence of shifts in means and variances of exchange rate changes, stock returns, and interest differentials that coincide with the current account adjustment regimes identified by the model.
Fractal Analysis of Time-Series Data Sets: Methods and Challenges
Many methods exist for quantifying the fractal characteristics of a structure via a fractal dimension. As a traditional example, a fractal dimension of a spatial fractal structure may be quantified via a box-counting fractal analysis that probes a manner in which the structure fills space. However, such spatial analyses generally are not well-suited for the analysis of so-called “time-series” fractals, which may exhibit exact or statistical self-affinity but which inherently lack well-defined spatial characteristics. In this chapter, we introduce and investigate a variety of fractal analysis techniques directed to time-series structures. We investigate the fidelity of such techniques by applying each technique to sets of computer-generated time-series data sets with well-defined fractal characteristics. Additionally, we investigate the inherent challenges in quantifying fractal characteristics (and indeed of verifying the presence of such fractal characteristics) in time-series traces modeled to resemble physical data sets
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The Term Structure of Forward Exchange Rates and the Forecastability of Spot Exchange Rates: Correcting the Errors
This paper revisits one of the oldest questions in international finance: does the forward exchange rate contain useful information about of the future path of the spot exchange rate? We present a theoretical framework and provide evidence that challenges the common view (Mussa (1979); Dornbusch (1980); Frenkel (1981); Cumby-Obstfeld (1984) that forward premia contain little information regarding subsequent changes in the spot exchange rate. Using weekly dollar-DM and dollar-sterling data on spot exchange rates and 1, 3, 6., and 12 month forward exchange rates, we find that, as predicted by the theoretical framework the term structure of forward exchange rates together with the spot exchange rate comprise a system that is well represented by a vector vector correction model. Employing Johansen's (1991) maximum likelihood approach, we test and confirm for each country the existence of 4 cointegrating relationships as predicted by the theory. We then test and confirm for each country the joint hypothesis that a basis for this cointegrating space is the vector of 4 forward premia. We next test, and reject for each country, the hypothesis that the spot exchange rate is weekly exogenous with respect to the term structure of forward rates. Out-of-sample simulations indicate that the information contained in the term structure of forward premia can be used to reduce the mean squared error in forecasting the spot rate by at least 33 percent at 6 month horizon and 50 percent at a 1 year horizon
Portable dynamic fundus instrument
A portable diagnostic image analysis instrument is disclosed for retinal funduscopy in which an eye fundus image is optically processed by a lens system to a charge coupled device (CCD) which produces recordable and viewable output data and is simultaneously viewable on an electronic view finder. The fundus image is processed to develop a representation of the vessel or vessels from the output data
Development of a tailored, telehealth intervention to address chronic pain and heavy drinking among people with HIV infection: integrating perspectives of patients in HIV care.
BACKGROUND:
Chronic pain and heavy drinking commonly co-occur and can infuence the course of HIV. There have been no interventions designed to address both of these conditions among people living with HIV (PLWH), and none that have used telehealth methods. The purpose of this study was to better understand pain symptoms, patterns of alcohol use, treatment experiences, and technology use among PLWH in order to tailor a telehealth intervention that addresses these conditions
SUBJECTS:
Ten participants with moderate or greater chronic pain and heavy drinking were recruited from a cohort of patients engaged in HIV-care (Boston Alcohol Research Collaborative on HIV/AIDS Cohort) and from an integrated HIV/primary care clinic at a large urban hospital.
METHODS:
One-on-one interviews were conducted with participants to understand experiences and treatment
of HIV, chronic pain, and alcohol use. Participants’ perceptions of the infuence of alcohol on HIV and chronic pain were explored as was motivation to change drinking. Technology use and treatment preferences were examined in the fnal section of the interview. Interviews were recorded, transcribed and uploaded into NVivo® v12 software for analysis. A codebook was developed based on interviews followed by thematic analysis in which specifc meanings were assigned to codes.
RESULTS:
A number of themes were identifed that had implications for intervention tailoring including: resilience
in coping with HIV; autonomy in health care decision-making; coping with pain, stress, and emotion; understanding treatment rationale; depression and social withdrawal; motives to drink and refrain from drinking; technology use and capacity; and preference for intervention structure and style. Ratings of intervention components indicated that participants viewed each of the proposed intervention content areas as “helpful” to “very helpful”. Videoconferencing was viewed as an acceptable modality for intervention delivery
CONCLUSIONS:
Results helped specify treatment targets and provided information about how to enhance intervention
delivery. The interviews supported the view that videoconferencing is an acceptable telehealth method of addressing chronic pain and heavy drinking among PLWH.UH2 AA026192 - NIAAA NIH HHSPublished versio
Connecting Cluster Substructure in Galaxy Cluster Cores at z=0.2 With Cluster Assembly Histories
We use semi-analytic models of structure formation to interpret gravitational
lensing measurements of substructure in galaxy cluster cores (R<=250kpc/h) at
z=0.2. The dynamic range of the lensing-based substructure fraction
measurements is well matched to the theoretical predictions, both spanning
f_sub~0.05-0.65. The structure formation model predicts that f_sub is
correlated with cluster assembly history. We use simple fitting formulae to
parameterize the predicted correlations: Delta_90 = tau_90 + alpha_90 *
log(f_sub) and Delta_50 = tau_50 + alpha_50 * log(f_sub), where Delta_90 and
Delta_50 are the predicted lookback times from z=0.2 to when each theoretical
cluster had acquired 90% and 50% respectively of the mass it had at z=0.2. The
best-fit parameter values are: alpha_90 = (-1.34+/-0.79)Gyr, tau_90 =
(0.31+/-0.56)Gyr and alpha_50 = (-2.77+/-1.66)Gyr, tau_50 = (0.99+/-1.18)Gyr.
Therefore (i) observed clusters with f_sub<~0.1 (e.g. A383, A1835) are
interpreted, on average, to have formed at z>~0.8 and to have suffered <=10%
mass growth since z~0.4, (ii) observed clusters with f_sub>~0.4 (e.g. A68,
A773) are interpreted as, on average, forming since z~0.4 and suffering >10%
mass growth in the ~500Myr preceding z=0.2, i.e. since z=0.25. In summary,
observational measurements of f_sub can be combined with structure formation
models to estimate the age and assembly history of observed clusters. The
ability to ``age-date'' approximately clusters in this way has numerous
applications to the large clusters samples that are becoming available.Comment: Accepted by ApJL, 4 pages, 2 figure
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Basal rot of narcissus : understanding pathogenicity in fusarium oxysporum f. sp. narcissi
Fusarium oxysporum is a globally distributed soilborne fungal pathogen causing root rots, bulb rots, crown rots and vascular wilts on a range of horticultural plants. Pathogenic F. oxysporum isolates are highly host specific and are classified as formae speciales. Narcissus is an important ornamental crop and both the quality and yield of flowers and bulbs can be severely affected by a basal rot caused by F. oxysporum f. sp. narcissi (FON); 154 Fusarium isolates were obtained from different locations and Narcissus cultivars in the United Kingdom, representing a valuable resource. A subset of 30 F. oxysporum isolates were all found to be pathogenic and were therefore identified as FON. Molecular characterisation of isolates through sequencing of three housekeeping genes, suggested a monophyletic origin with little divergence. PCR detection of 14 Secreted in Xylem (SIX) genes, previously shown to be associated with pathogenicity in other F. oxysporum f. spp., revealed different complements of SIX7, SIX9, SIX10, SIX12 and SIX13 within FON isolates which may suggest a race structure. SIX gene sequences were unique to FON and SIX10 was present in all isolates, allowing for molecular identification of FON for the first time. The genome of a highly pathogenic isolate was sequenced and lineage specific (LS) regions identified which harboured putative effectors including the SIX genes. Real-time RT-PCR, showed that SIX genes and selected putative effectors were expressed in planta with many significantly upregulated during infection. This is the first study to characterise molecular variation in FON and provide an analysis of the FON genome. Identification of expressed genes potentially associated with virulence provides the basis for future functional studies and new targets for molecular diagnostics
Theoretical studies of the potential surface for the F - H2 greater than HF + H reaction
The F + H2 yields HF + H potential energy hypersurface was studied in the saddle point and entrance channel regions. Using a large (5s 5p 3d 2f 1g/4s 3p 2d) atomic natural orbital basis set, a classical barrier height of 1.86 kcal/mole was obtained at the CASSCF/multireference CI level (MRCI) after correcting for basis set superposition error and including a Davidson correction (+Q) for higher excitations. Based upon an analysis of the computed results, the true classical barrier is estimated to be about 1.4 kcal/mole. The location of the bottleneck on the lowest vibrationally adiabatic potential curve was also computed and the translational energy threshold determined from a one-dimensional tunneling calculation. Using the difference between the calculated and experimental threshold to adjust the classical barrier height on the computed surface yields a classical barrier in the range of 1.0 to 1.5 kcal/mole. Combining the results of the direct estimates of the classical barrier height with the empirical values obtained from the approximation calculations of the dynamical threshold, it is predicted that the true classical barrier height is 1.4 + or - 0.4 kcal/mole. Arguments are presented in favor of including the relatively large +Q correction obtained when nine electrons are correlated at the CASSCF/MRCI level
The Impact of Social Deprivation on Paranoia, Hallucinations, Mania and Depression: The Role of Discrimination Social Support, Stress and Trust
The negative implications of living in a socially unequal society are now well documented. However, there is poor understanding of the pathways from specific environmental risk to symptoms. Here we examine the associations between social deprivation, depression, and psychotic symptoms using the 2007 Adult Psychiatric Morbidity Survey, a cross-sectional dataset including 7,353 individuals. In addition we looked at the mediating role of stress, discrimination, trust and lack of social support. We found that the participants' neighbourhood index of multiple deprivation (IMD) significantly predicted psychosis and depression. On inspection of specific psychotic symptoms, IMD predicted paranoia, but not hallucinations or hypomania. Stress and trust partially mediated the relationship between IMD and paranoid ideation. Stress, trust and a lack of social support fully mediated the relationship between IMD and depression. Future research should focus on the role deprivation and social inequalities plays in specific manifestations of psychopathology and investigate mechanisms to explain those associations that occur. Targeting the mediating mechanisms through appropriate psychological intervention may go some way to dampen the negative consequences of living in an unjust society; ameliorating economic injustice may improve population mental health
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