The influence of clothing on first impressions : Rapid and positive responses to minor changes in male attire

Clothing communicates information about the wearer and first impressions can be heavily influenced by the messages conveyed by attire. The purpose of this paper is to investigate the effect of minor changes in clothing on the perception of a male model, in the absence of facial information with limited time exposurePeer reviewe

Event-related GARCH: the impact of stock dividends in Turkey

Cash dividends and rights issues on the Istanbul Stock Exchange are commonly accompanied by large stock dividend payments. This paper tests the proposition that stock dividends have no effect on company value, using a novel GARCH process with event-related intercept terms to capture induced changes in the volatility of stock prices. Returns rise in advance of stock dividend payments, but this effect becomes statistically insignificant when proper allowance is made for heteroscedasticity. Volatility rises after stock dividend payments, and this is attributed to persistence following exceptionally large price movements around the ex dividend day, rather than to any transitory rise in the unconditional returns variance. The study does document some irrationality in responses to cash dividends, with prices rising/ falling after increased/ decreased dividend payments, rather than after the much earlier dividend announcements

Efficiency and volatility on the Istanbul Stock Exchange

This thesis investigates characteristics of the prices of shares traded on the Istanbul Stock Exchange (ISE), an important and fast-growing market. We look at five issues: the shape of the distribution of daily returns the predictability of these returns the presence of day-of-the-week effects in the mean and variance of returns the behaviour of the mean and variance of returns around stock split and dividend dates and the predictability of variances, and in particular the performance of adaptive models relative to the GARCH models. Our main findings can be summarised as follows. First, the hypothesis of normality is rejected, mainly due to excess kurtosis. To explain excess kurtosis, we used an autoregressive conditional heteroskedastic (ARCH) model, and a GARCH(1,1) model is found to fit the ISE index data well. A significant further finding, based on a t-GARCH-M model is that in the early years of the exchange, mean returns were significantly influenced by the returns variance. Second, standard tests for serial correlation, and for runs of same-sign returns, show that the hypothesis of a random walk can be rejected, with index returns showing significant first and second order serial correlation. Again, these effects are stronger in the early years of the exchange. Third, using a GARCH model, we find no strong evidence of the day of the week effect in mean returns on the index or on the 20 actively traded companies. But there is evidence to suggest that the market is more volatile on Mondays and after holidays. Again, these effects are not stable over time. Taken together, these results point to the market becoming progressively more efficient and more integrated with the international capital market over the period of the study. Fourth, the results from the EV-GARCH model, a GARCH model with event dependent intercept terms, a technical novelty, show that there is no effect on mean returns from stock dividends. Surprisingly, cash dividends do cause returns to rise/fall after their payment. On the other hand, stock dividends do significantly increase the variance of returns around the event day, and for several weeks thereafter. Finally, although we have characterised the daily returns series by an autoregressive model with a GARCH process for volatility, it turns out that the GARCH model does not unambiguously dominate alternatives in forecasting and trading applications. In 5- to 20-day ahead forecasts, the GARCH model is slightly more accurate than four alternatives, including exponential smoothing models (RiskMetrics) and historic volatility. However, it is (inevitably) less accurate than a model which pools forecasts from all models. In a simulated options market - another technical innovation of the thesis - we find that traders using a GARCH model would on balance lose money to traders using other methods, in spite of the apparently greater accuracy of the GARCH forecasts. This confirms for volatility forecasts an important result which is already know to hold for mean forecasts - that in forecasting financial markets, there is little correlation between meansquare accuracy and trading profitability

Intracranial dermoid cysts: variations of radiological and clinical features

Background: Intracranial dermoid cysts are uncommon, and their clinical features as well as surgical management differ from patient to patient. Dermoids are generally benign lesions, but may cause spontaneous complications such as meningitis and/or hydrocephalus due to rupture and epileptic seizures depending on their location. Little has been reported about characteristic imaging findings with resulting therapeutic considerations, and only a few reports exist about associated hydrocephalus. Imaging modalities have changed and can facilitate differential diagnosis and follow-up if applied correctly. In this paper, we attempt to contribute our clinical experience with the management of dermoid cysts. Patients and methods: The charts of five men and two women with intracranial dermoid cysts were retrospectively reviewed. The patients were treated between September 1993 and September 2006. Selected patients are presented in detail. Results: Tumour location, size and radiographic characteristics varied in each patient. Clinical presentations comprised focal neurological deficits as well as epileptic seizures, persistent headache, mental changes and psycho-organic syndromes. One patient underwent delayed ventriculo-peritoneal shunting after ruptured fatty particles caused obstructive hydrocephalus. Despite dermoid rupture into the subarachnoid space, three patients never developed hydrocephalus. Diffuse vascular supra-tentorial lesions were seen in one patient as a result of aseptic meningitis. Diffusion-weighted imaging (DWI) hyperintensity in dermoids is related to decrease of water proton diffusion and should be used for both the diagnosis and follow-up of this lesion. Conclusion: Although dermoid cysts are known to be benign entities per se, their rupture can cause a wide range of symptoms including aseptic meningitis and/or hydrocephalus. This may be due to intraventricular obstruction and/or paraventricular compression. While rupture does not necessarily bring about hydrocephalus, radical removal of the tumour and close monitoring of ventricular size is required. Although not widely recognised as such, DWI is considered to be a useful imaging modality in the diagnosis and follow-up of dermoid

Intracranial Vertebral Artery Aneurysms : Clinical Features and Outcome of 190 Patients

BACKGROUND: Vertebral artery (VA) aneurysms comprise approximately one-third of posterior circulation aneurysms. They are morphologically variable, and located critically close to the cranial nerves and the brainstem. We aim to represent the characteristics of these aneurysms and their treatment, and to analyze the outcome. METHODS: We reviewed retrospectively 9709 patients with intracranial aneurysms. Of these, we included 190 with aneurysms at the VA or VA posterior inferior cerebellar artery junction. The patients were treated in the Department of Neurosurgery, Helsinki, Finland, between 1934 and 2011. RESULTS: The 190 patients had 193 VA aneurysms, among which 131 (68%) were ruptured, The VA aneurysm caused a mass effect in 7 and ischemia in 2 patients. Compared to 4387 patients with a ruptured aneurysm in other locations, those with a VA aneurysm were older, their aneurysms were more often fusiform, and more often caused intraventricular hemorrhages. Among surgically treated aneurysms, clipping was the treatment in 91 (88%) saccular and 11 (50%) fusiform aneurysms. Treatment was endovascular in 13 (9%), and multimodal in 6 (4%) aneurysms, Within a year after aneurysm diagnosis, 53 (28%) patients died. Among the survivors, 104 (93%) returned to an independent or to their previous state of life; only 2 (2%) were unable to return home. CONCLUSIONS: Microsurgery is a feasible treatment for VA aneurysms, although cranial nerve deficits are more common than in endovascular surgery. Despite the challenge of an often severe hemorrhage, of challenging morphology, and risk for laryngeal palsy, most patients surviving the initial stage return to normalcy.Peer reviewe