Market Illiquidity and the Bid-Ask Spread of Derivatives

This paper analyzes the impact of illiquidity of a stock on the pricing of derivatives. In particular, it is shown how illiquidity generates a bid-ask spread in an option on this stock, even in the absence of other imperfections, such as transaction costs and asymmetry of information. Moreover, the spread is shown to be asymmetric with respect to the option price under perfect liquidity. This fact explains the appearance of a smile e$ect when the implied volatility is estimated from the mid-quote.

Bank performance and noninterest income: evidence from countries in the Asian region

Noninterest income (NII) is income generated by banks from sources other than interest payments. Studies conducted on the relationship between NII and bank risk for the USA and Europe have found that emphasis on income diversification lowers risk in European banks but exacerbates it in American banks. Current research on Asian banks has not led to a coherent view of the relationship between NII and bank risk. We employ data over 25 years for 24 Asian countries to examine this relationship. Using the GMM estimation approach we estimate equations for two time-periods, 1996–2007 and 2008–2018, to examine the NII-bank risk relationship in the presence of some controlling financial, macroeconomic and policy variables. Our results show that non-interest income worsens bank risk for all 24 countries as well as for sub-groups of countries. We also find that, by and large, economic growth improves bank risk while inflation above a threshold worsens it. Finally, our proxy measure for monetary policy improves bank risk though fiscal policy seems to have no effect

Neural activity dissociation between thought-based and perception-based response conflict

Based on the idea that intentions have different penetrability to perception and thought (Fodor, 1983), four Stroop-like tasks, AA, AW, WA, and WW are used, where the A represents an arrow and the CPPR (closest processing prior to response) is perception, and the W represents a word and the CPPR is thought. Event-related brain potentials were recorded as participants completed these tasks, and sLORETA (standardized low resolution brain electromagnetic tomography) was used to localize the sources at specific time points. These results showed that there is an interference effect in the AA and WA tasks, but not in the AW or WW tasks. The activated brain areas related to the interference effect in the AA task were the PFC and ACC, and PFC activation took place prior to ACC activation; but only PFC in WA task. Combined with previous results, a new neural mechanism of cognitive control is proposed

The Shape of Species Abundance Distributions Across Spatial Scales

Species abundance distributions (SADs) describe community structure and are a key component of biodiversity theory and research. Although different distributions have been proposed to represent SADs at different scales, a systematic empirical assessment of how SAD shape varies across wide scale gradients is lacking. Here, we examined 11 empirical large-scale datasets for a wide range of taxa and used maximum likelihood methods to compare the fit of the logseries, lognormal, and multimodal (i.e., with multiple modes of abundance) models to SADs across a scale gradient spanning several orders of magnitude. Overall, there was a higher prevalence of multimodality for larger spatial extents, whereas the logseries was exclusively selected as best fit for smaller areas. For many communities the shape of the SAD at the largest spatial extent (either lognormal or multimodal) was conserved across the scale gradient, despite steep declines in area and taxonomic diversity sampled. Additionally, SAD shape was affected by species richness, but we did not detect a systematic effect of the total number of individuals. Our results reveal clear departures from the predictions of two major macroecological theories of biodiversity for SAD shape. Specifically, neither the Neutral Theory of Biodiversity (NTB) nor the Maximum Entropy Theory of Ecology (METE) are able to accommodate the variability in SAD shape we encountered. This is highlighted by the inadequacy of the logseries distribution at larger scales, contrary to predictions of the NTB, and by departures from METE expectation across scales. Importantly, neither theory accounts for multiple modes in SADs. We suggest our results are underpinned by both inter- and intraspecific spatial aggregation patterns, highlighting the importance of spatial distributions as determinants of biodiversity patterns. Critical developments for macroecological biodiversity theories remain in incorporating the effect of spatial scale, ecological heterogeneity and spatial aggregation patterns in determining SAD shape.Peer reviewe

Real-Time Manipulation with Magnetically Tunable Structures

Magnetically tunable micropillar arrays with uniform, continuous and extreme tilt angles for real-time manipulation are reported. We experimentally show uniform tilt angles ranging from 0° to 57°, and develop a model to accurately capture the behavior. Furthermore, we demonstrate that the flexible uniform responsive microstructures (μFUR) can dynamically manipulate liquid spreading directionality, control fluid drag, and tune optical transmittance over a large range.United States. Air Force Office of Scientific Research (AFOSR, Grant FA9550-11-1-0059

Nuevo concepto de vehículo

En el siguiente documento se va a exponer un nuevo concepto de automoción. El proyecto abarca el desarrollo de un vehículo asequible por su bajo coste y mas eficiente cualquier otro del mercado cuya característica más salientable es su capacidad de adaptación a las necesidades puntuales del usuario. Esto se debe a su composición estructural modular.Departamento de Ciencias de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodesia y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de FabricaciónGrado en Ingeniería en Diseño Industrial y Desarrollo de Product

Stabilization of Bilateral Progressive Rheumatoid Corneal Melt with Infliximab

Purpose. To report the use of infliximab in the rapid stabilization of a case of progressive, bilateral rheumatoid peripheral ulcerative keratitis (PUK) that failed to respond to conventional immunosuppressive therapy. Methods. A single interventional case report. Results. A patient with rheumatoid arthritis presented with bilateral PUK following a 2-month history of ocular discomfort and redness. His systemic prednisolone (PDN) and methotrexate (MTX) were increased and, despite an initial favorable response, bilateral recurrent corneal perforations ensued. Both eyes underwent cyanoacrylate glue repair, amniotic membrane transplantation (AMT), and penetrating keratoplasty (PKP). Recurrence of the disease and bilateral perforations of the second PKP in both eyes prompted administration of intravenous infliximab immediately after the fourth PKP. The disease activity rapidly settled in both eyes, and at eighteen-month followup, after 12 infliximab infusions, the PUK remains quiescent with no further graft thinning or perforation. Conclusion. Infliximab can be used to arrest the progression of severe bilateral rheumatoid PUK in cases that are refractory to conventional treatment

job tenure as a potential protective factor

Funding Information: The authors would like to thank Patricia Soares, PhD, from the Portuguese School of Public Health, Lisbon, Portugal, for her assistance in planning and reviewing the statistical analysis of the study and for her contribution to the manuscript scientific writing. Funding Information: The article processing fee has been supported by Lundbeck Portugal. Publisher Copyright: Copyright © 2022 Antao, Sacadura-Leite, Correia and Figueira.Burnout is an impactful occupational health phenomenon to which doctors and nurses have been more exposed during the COVID-19 pandemic. The objectives of this study were to measure the dimensions of burnout—emotional exhaustion, depersonalization and personal accomplishment—in a hospital healthcare population after the second COVID-19 wave and to study their association with sociodemographic variables and previous COVID-19 infection. We invited 112 healthcare professionals (doctors and nurses) who attended the occupational health department of a tertiary hospital in March–July 2021. Emotional exhaustion, depersonalization and personal accomplishment were measured by the Maslach Burnout Inventory. Linear-regression analyses were conducted to explore relationships between burnout dimensions and sociodemographic variables. Differences between groups according to previous COVID-19 infection were verified using the t-test and when appropriate the Mann–Whitney test (for continuous variables), the chi-square test and when appropriate the Fisher exact test (for categorical variables). We surveyed 106 subjects (95% response rate). High emotional exhaustion and depersonalization were reported by 33.0 and 18.4% of participants, respectively; 21.4% reported low personal accomplishment. Job tenure was associated with depersonalization and personal accomplishment. For each 1-year increase in job tenure, depersonalization decreases 0.14 (95% CI [−0.23, −0.04]) and personal accomplishment increases 0.16 (95% CI [0.06, 0.25]). Gender was associated with emotional exhaustion (being male increases emotional exhaustion 5.62-fold [95% CI: 1.33; 9.92]). The prevalence of high emotional exhaustion, high depersonalization and low personal accomplishment after the second COVID-19 wave was relevant and should not be overlooked. Our findings suggest that job tenure may play a protective role in healthcare workers’ burnout.publishersversionpublishe

Flow and Heat Transfer Processes in an Inertance Type Pulse Tube Refrigerator

Presented at the 16th International Cryocooler Conference, held May 17-20, 2008 in Atlanta, Georgia.A time-dependent axisymmetric (r-z) numerical study is reported here for the investigation of the fundamental flow and heat transfer processes found in an inertance type pulse tube refrigerator (IPTR). The general design of an IPTR incorporates a pressure wave generator, a transfer line, an aftercooler, a regenerator, a pulse tube, a pair of heat exchangers for the cold and hot ends of the pulse tube, an inertance tube and a reservoir. The performance of the IPTR system is simulated using computational fluid dynamics (CFD). The IPTR is driven by a cyclically moving piston at one end of the system operating at a fixed frequency with helium as the working fluid. Both constant temperature and convective heat transfer boundary conditions are examined along the external walls of the hot heat exchangers. The simulations reveal interesting time-dependent flow patterns that develop in the pulse tube due to the fluctuations caused by the piston and the presence of the inertance tube. The secondary-flow recirculation patterns in the pulse tube reduce the heat pumping effect from the low-temperature heat exchanger to the high-temperature heat exchangers