Miracle-dz/UniFAR-FTUs huggingface dataset:
The leverage effect in stochastic volatility: new models, Bayesian inference, and model selection

A striking empirical feature of many financial time series is that when the price drops, the future volatility increases. This negative correlation between the financial return and future volatility processes was initially addressed in Black 76 and explained based on financial leverage, or a firm's debt-to-equity ratio: when the price drops, financial leverage increases, the firm becomes riskier, and hence, the future expected volatility increases. The phenomenon is, therefore, traditionally been named the leverage effect. In a discrete time Stochastic Volatility (SV) model framework, the leverage effect is often modelled by a negative correlation between the innovation processes of return and volatility equations. These models can be represented as state space models in which the returns and the volatilities are considered as the observed and the latent state variables respectively. Including the leverage effect in the SV model not only results in a better fit of the model to several types of financial time series, but also yields significant improvements in option pricing applications. Statistical inference and model selection for such models are, in general, involved, mainly due to the fact that the model likelihood is not available in analytical closed-form and appears as a high-dimensional integral over the latent volatility vector. In this thesis, we apply Markov chain Monte Carlo (MCMC) methods (based on the influential work of Jacquier Et al 94) for parameter estimation. For model selection purposes, based on the Deviance Information Criterion (DIC) (introduced by Spiegelhalter Et al 02), we utilize a version of the DIC in which the latent volatility variables are integrated out. We then elaborate on new models for the leverage effect. The important contributions of this thesis can be outlined as follows: In Section Bayesian Model Selection we demonstrate, through extensive simulations, that when applying the DIC to the SV model selection problem, the latent volatility variables must be integrated out, otherwise the model selection conclusions will be potentially misleading. We use particle filtering algorithm (based on sequential Monte Carlo methods) to estimate the marginal likelihood of the SV model. We then use numerical maximization techniques to calculate the Akaike/Bayesian information criteria to test for the leverage effect in a selection of real financial time series. This method is applied as an alternative to the DIC model selection method and is shown to yield similar results (Section MLforSV). In order to capture a potential nonlinear extreme value dependence structure between the returns and volatilities, in Chapter 3 we propose a new model that incorporates copulas into SV models. We develop the corresponding Bayesian inference methodology for the new model and show that for a wide selection of stock prices and indices, a Gaussian copula is favoured to the extreme value copulas. In Section SVAL we propose a new model which assumes that the leverage effect is a time-varying stochastic process. …
Antecedents and Outcomes of Hospitality Loyalty

Customer loyalty is vital for hospitality businesses. A large body of literature has accumulated on the topic, requiring integration to form generalizations and to make it accessible to operators. In this research, I provide a conceptual framework for classifying indirect and direct loyalty antecedents and outcomes, and quantifying its components using meta-analysis. I analyze 102 studies that produce 423 effect sizes, which are distilled into a summary effect size for each relationship. The analysis reveals strong relationships between direct loyalty antecedents (satisfaction, emotional commitment, service quality, trust, and switching costs) and overall loyalty. However, the magnitude of effects declines significantly as the outcome moves from attitudinal loyalty to behavioral intentions to behavior. As most of our knowledge about loyalty is based on intention measures, the findings suggest that effects on actual loyalty may be smaller than the research would suggest. Indirect loyalty antecedents include experiential, monetary, and relational attributes. It appears that each of these categories affect loyalty through somewhat different processes, although they all relate to satisfaction. The meta-analysis approach allows operators to glean key findings relevant to their business from a single source. It enables researchers to answer research questions and to summarize relationships from a body of literature that cannot be tested conclusively with a single study.
Reinvestment and Falls in Community-Dwelling Older Adults

Background. Falls are common in older adults and have many adverse consequences. In an attempt to prevent further incidents, elder fallers may consciously monitor and control their movements. Ironically, conscious movement control may be one factor that contributes to disruption of automaticity of walking, increasing the likelihood of subsequent falls. Objective. The Movement Specific Reinvestment Scale (MSRS), which aims to measure the propensity for movement-related self-consciousness and for conscious processing of movement, was used to try to discriminate elder fallers from non-fallers. Methods. Fifty-two volunteer older adults, aged 65 or above, participated. In addition to the 10-item MSRS, participants completed the Mini-Mental State Examination questionnaire, Timed “Up & Go” test, and Four Word Short-Term Memory test. Demographics including age, gender, and history of falling were collected. Results. Elder fallers scored significantly higher than non-fallers on both the movement self-consciousness and conscious motor processing components of the MSRS. Logistic regression revealed a significant association between the MSRS (conscious motor processing component) and “faller or non-faller” status. Conclusions. Elder fallers may have a higher propensity to consciously control their movements. The MSRS shows potential as a clinical tool with which to predict falls in the elderly, as well as to gain insight into the perception of safety during walking in any impaired patient.
Family group conferences, part one: Australia's first project within child protection

Family decision making through Family Group Conferences has been trialled in a pilot project by the Mission of St James and St John, Victoria, for the past 16 months (as of February 1994) in a two year Project. This article, the first of a series of two, intends to briefly explain the technique and how the project was established in Victoria. The theoretical basis, or project assumptions, will be outlined, together with the obstacles which currently prevent the wider implementation of the practice. The project was independently evaluated from October 1992 up to 31 August 1993 (Swain, 1993a; 1993b). Key findings of that evaluation will be discussed in the second article in this series along with practice issues that need further exploration.
Improved results on frequency weighted balanced truncation

In this paper, we present some new results on frequency weighted balanced truncation which is a significant improvement on Lin and Chiu's frequency weighted balanced truncation technique [7]. The reduced order models which are guaranteed to be stable in case of double-sided weighting, are obtained by direct truncation. Two sets of simple, elegant and easily calculatable a priori error bounds are also derived. A numerical example and comparison with other well-known techniques show the effectiveness of the proposed technique.
Speech Intelligibility and Passive, Level-Dependent Earplugs

Objectives:Noise-induced hearing loss is one of the most common occupational diseases. Military personnel are at especially high risk due to the broad range of military noise hazards and the frequency of exposure. Hearing protectors are vital for this particular workforce, yet they can impede the ability to understand necessary communication in the field. Level-dependent hearing protectors are designed to protect the auditory system from the hazards of impulse noise, while preserving the ability to hear speech and other important auditory signals. The aim of this study was to evaluate the effect of two different passive, level-dependent earplugs (Combat Arms Earplugs; Sonic II Ear valves) on speech understanding of normal-hearing listeners in the presence of low-level background noise. The Combat Arms Earplug, developed specifically for use by military personnel, represented devices that attenuate impulse noise using small orifices and the Sonic II ear valve represented devices using an internal diaphragm. Design:This study used a repeated-measures experimental design. Four scrambled lists of each of the four Northwestern University No. 6 50-word lists were presented in random order at 65 dB SPL in the presence of quiet and two different types of background noise: multitalker and military vehicle noise; using three ear conditions: NP (open ear), CA (Combat Arms Earplugs), and SO (Sonic II earplugs); and three signal-to-noise ratios (SNRs): −10, 0, and +10 dB. Word recognition scores (WRSs) of 18 native English-speaking adults with normal hearing sensitivity were measured in all test conditions. The percentage of words correctly repeated was used to determine differences between the two different level-dependent devices, types of background noise, and SNRs. Results:Results showed a statistically significant increase in WRS as SNR increased from −10 to +10 dB. A repeated-measures analysis of variance for ear condition × noise × SNR indicated a significant main effect for SNR but not for type of noise or ear condition. A slight but significant interaction was found for SNR and ear condition. Conclusions:SNR had great impact on the ability of listeners to understand speech in the presence of background noise; however, the type of noise and the type of level-dependent device used did not. The results of the study support the notion that individuals potentially subjected to high-level impulse noise should be able to use level-dependent earplugs in low-level continuous noise without compromising speech understanding. More specifically, the passive, level-dependent earplugs currently used by military personnel do not appear to be detrimental to speech communication for listeners with normal hearing when the speech is at an average conversational level and the listener is actively attending to the signal.
Long-term sickness absence and disability pension with psychiatric diagnoses: A population-based cohort study

Sickness absence certified with psychiatric diagnoses is increasing in many Western countries. A substantial proportion of the sickness absentees never return to work, but ends up with a permanent disability pension (DP). This study investigated the incidence of long-term sickness absence (LTSA) with different psychiatric diagnoses, and tested predictors of the transition to permanent DP. A special objective was to explore previously reported gender differences, using a population-based cohort study. The population at risk of LTSA was 106,674 occupational active men and 89,356 women in a Norwegian county in 1994; 314 women and 203 men with LTSA >8weeks, certified with a psychiatric diagnosis, were followed to the end of 1999, with DP as the endpoint. Diagnoses on sickness certificates, age, gender and income were used as explanatory variables in Cox regression analysis. Annual incidence of LTSA with a psychiatric diagnosis was 7.0/1000/year for women and 3.8/1000 for men; 72% of the women and 50% of the men had a diagnosis indicating depression. During follow-up, 32% of the men and 25% of the women obtained DP. Increasing age, male gender, low income and a diagnosis of psychosis or “other” increased the DP risk. Separate analysis for men indicated a different effect of age and a larger role of serious mental illness. The study verified that women more often than men had LTSA with psychiatric diagnoses, especially with depression. Men were at higher risk of transition to DP, and the study suggested some possible explanations.
In situ detection of AP sites and DNA strand breaks bearing 3'‐phosphate termini in ischemic mouse brain

Our aims were to examine whether oxidative DNA damage was elevated in brain cells of male C57BL/6 mice after oxidative stress, and to determine whether neuronal nitric oxide synthase (nNOS) was involved in such damage. Oxidative stress was induced by occluding both common carotid arteries for 90 min, followed by reperfusion. Escherichia coli exonuclease III (Exo III) removes apyrimidinic or apurinic (AP) sites and 3'‐phosphate termini in single‐strand breaks, and converts these lesions to 3'OH termini. These ExoIII‐sensitive sites (EXOSS) can then be postlabeled using digoxigenin‐11‐dUTP and Klenow DNA polymerase‐I, and detected using fluorescein isothiocyanate‐IgG against digoxigenin. Compared with the non‐ischemia controls, the density of EXOSS‐positive cells was elevated at least 20‐fold (P < 0.01) at 15 min of reperfusion, and remained elevated for another 30 min. EXOSS mainly occurred in the cell nuclei of the astrocytes and neurons. Signs of cell death were detected at 24 h of reperfusion and occurred mostly in the neurons. Both DNA damage and cell death in the cerebral cortical neurons were abolished by treatment with 3‐bromo‐7‐nitroindazole (30 mg/kg, intraperitoneal), which specifically inhibited nNOS. Our results suggest that nNOS, its activator (calcium), and peroxynitrite exacerbate oxidative DNA damage after brain ischemia. —Huang, D. , Shenoy, A. , Cui, J., Huang, W. , Liu, P. In situ detection of AP sites and DNA strand breaks bearing 3′‐phosphate termini in ischemic mouse brain. FASEB J. 14, 407–417 (2000)
The management of chronic ulcers with an acidoxidising solution.

OBJECTIVE Chronic ulcers are an intractable problem in many patients and are associated with impaired quality of life and high health-care costs. In an attempt to improve outcome, our centre began cleansing wounds with a novel spray acidoxidising solution (Nexodyn) with unique physicochemical features, pH <3.0; oxidation reduction potential >1000mV; and free chlorine content (>95% HClO). METHOD A retrospective analysis was conducted in patients with numerous comorbidities and an unsatisfactory response to standard therapy. The solution was administered for six weeks and the patients' clinical course evaluated using standard measures of wound healing, pain and bioburden. RESULTS We assessed 20 patients with a mean time since ulcer onset of 23.7 months. Complete resolution of the lesion was achieved in 25% of cases (p=0.005). In the group as a whole, wound size decreased significantly (11% mean reduction versus baseline; p=0.039). In the relatively short six-week observation period, significant reductions versus baseline were also observed in control of wound bioburden (p=0.005) and ulcer-related pain score (p<0.001). Furthermore, the wound bed preparation score suggests an improved wound microenvironment with better wound bed cleansing and the presence of granulation tissue. There were no adverse systemic effects of treatment nor adverse local effects in the wound bed or on healthy periwound skin. CONCLUSION Encouraging initial results in a population refractory to standard management provide evidence that this new product may make a helpful contribution to the care of chronic ulcers. The integration of this cleansing solution into standard care contributes to the modulation of local microenvironmental responses that inhibit physiological healing processes while also contributing to the reduction of bacterial load.
Consistency of Likeability of Objects across Views and Time

Subjective impressions of face images (eg personality trait judgments) are consistent across exposure durations and viewpoints. In this study, we investigated whether subjective likeability of common non-face objects would also be consistent. Participants rated the likeability of 32 common objects (eg chair, car, and kettle). Although the rated likeability scores were generally higher for objects shown in three-quarter views than for the same objects shown in full-frontal views, object-wise correlations across the views were significant (experiment 1). The likeability ratings based on brief exposure duration (eg 100 ms) also significantly correlated with those based on unlimited exposure duration (experiment 2). Even when the duration was brief, the consistency across the views was replicated. The findings confirmed that the subjective likeability of common objects is consistent and the process underlying it is efficient, similar to those of faces. However, the mean rated likeability was higher for longer exposure durations, suggesting a negative bias for briefly observed objects. Since this bias is contrary to previously reported findings for faces, the mechanisms for determining subjective likeability of common objects may be partially different from those of faces.
Temporal lobe networks supporting the comprehension of spoken words

&NA; Auditory word comprehension is a cognitive process that involves the transformation of auditory signals into abstract concepts. Traditional lesion‐based studies of stroke survivors with aphasia have suggested that neocortical regions adjacent to auditory cortex are primarily responsible for word comprehension. However, recent primary progressive aphasia and normal neurophysiological studies have challenged this concept, suggesting that the left temporal pole is crucial for word comprehension. Due to its vasculature, the temporal pole is not commonly completely lesioned in stroke survivors and this heterogeneity may have prevented its identification in lesion‐based studies of auditory comprehension. We aimed to resolve this controversy using a combined voxel‐based—and structural connectome—lesion symptom mapping approach, since cortical dysfunction after stroke can arise from cortical damage or from white matter disconnection. Magnetic resonance imaging (T1‐weighted and diffusion tensor imaging‐based structural connectome), auditory word comprehension and object recognition tests were obtained from 67 chronic left hemisphere stroke survivors. We observed that damage to the inferior temporal gyrus, to the fusiform gyrus and to a white matter network including the left posterior temporal region and its connections to the middle temporal gyrus, inferior temporal gyrus, and cingulate cortex, was associated with word comprehension difficulties after factoring out object recognition. These results suggest that the posterior lateral and inferior temporal regions are crucial for word comprehension, serving as a hub to integrate auditory and conceptual processing. Early processing linking auditory words to concepts is situated in posterior lateral temporal regions, whereas additional and deeper levels of semantic processing likely require more anterior temporal regions.
Thickening of the knee joint cartilage in elite weightlifters as a potential adaptation mechanism

Thickening and increase of area of cartilage have been proposed as two alternative mechanisms of cartilage functional adaptation. The latter has been reported in endurance sportsmen. In weightlifters, extreme strain applied to the articular surfaces can result in other forms of adaptation. The aim of this research is to determine whether cartilage thickness is greater in elite weightlifters than in physically inactive men. Weightlifters (13) and 20 controls [age and body mass index (BMI) matched] underwent knee Magnetic Resonance Imaging (MRI). A single sagittal slice of the knee was taken and cartilage thickness was measured in five and six regions of the medial and lateral femoral condyles, respectively. The analyzed segments represented weight‐bearing and nonweight‐bearing regions. The tibia cartilage in the weight‐bearing area was also measured. The time of training onset and its duration in the weightlifter group were recorded. The cartilage was found to be significantly thicker in weightlifters in most of the analyzed regions. The distribution of cartilage thickness on the medial and lateral femoral condyles was similar in both groups. The duration of training was not associated with cartilage thickness, but the time of training onset correlated inversely with cartilage thickness. It is possible that in high‐strain sports, joint cartilage can undergo functional adaptation by thickening. Thus, mechanical loading history could exert a postnatal influence on cartilage morphology. Clin. Anat. 27:920–928, 2014. © 2014 Wiley Periodicals, Inc.
Thin Bandstop Frequency-Selective Structures Based on Loop Resonator

Circular and elliptical loop resonators are proposed as the unit cell of 3-D frequency-selective structure aiming to reduce the structure thickness. The structure exhibits a pseudoelliptic response by utilizing the coupling between the two quasi-TEM modes, which are concentrated in air and substrate regions of the unit cell. Using elliptical loop with stepped-impedance resonator (SIR), the thickness of the structure can be reduced by 80% compared to previous structures. A comparison between the response of the structure employing the microstrip line as the resonator and the structure using the proposed loop resonators is performed. Three prototypes are designed, fabricated, and tested. The first structure is designed to have a dual-band bandstop response using two half-circular loops with end via holes; it has center frequencies at 10 and 14.3 GHz with −3 dB fractional bandwidths of 6.7% and 6.6%, respectively. A half-elliptical loop with SIR is employed in the second structure to achieve more thickness reduction. The third structure is designed to exhibit a dual-polarized bandstop response. Stable frequency response under various angles of incidence is obtained.
Spring Mass Characteristics of the Fastest Men on Earth

The spring mass model has widely been used to characterize the whole body during running and sprinting. However the spring mass characteristics of the world's fastest men are still unknown. Thus the aim of this study was to model these characteristics for currently the 3 fastest men on earth (Usain Bolt, Tyson Gay and Asafa Powell). This was done by using data collected during the 2009 World championships in Berlin and the modelling method of Morin et al. 21. Even though Bolt achieved the greatest velocity (12.3 m.s - 1) over the 60-80 m split compared to his competitors, his estimated vertical stiffness (355.8 kN.m - 1) and leg stiffness (21.0 kN.m - 1) were significantly lower than his competitors. This reduction in stiffness is a consequence of Bolt's longer contact time (0.091 s) [corrected] and lower step frequency (4.49 Hz). Thus Bolt is able to run at a greater velocity but with lower stiffness compared to his competitors.
The Naive versus the Adaptive Boston Mechanism

The Boston mechanism is often criticized for its manipulability and the resulting negative implications for welfare and fairness. Nonetheless, it is one of the most popular school choice mechanisms used in practice. In this paper, we first study the traditional (naive) Boston mechanism (NBM) in a setting with no priority structure and single uniform tie-breaking. We show that it imperfectly rank dominates the strategyproof Random Serial Dictatorship (RSD). We then formalize an adaptive variant of the Boston mechanism (ABM), which is also sometimes used in practice. We show that ABM has significantly better incentive properties than NBM (it is partially strategyproof), while it shares most of NBM's efficiency advantages over RSD as markets get large. However, while a direct efficiency comparison of NBM and ABM via imperfect dominance is inconclusive, numerical simulations suggest that NBM is still somewhat more efficient than ABM, which can be interpreted as the cost of partial strategyproofness one pays when choosing ABM over NBM. Our results highlight the subtle trade-off between efficiency and strategyproofness a market designer must make when choosing between the two Boston mechanisms and RSD.