Estimation of flexible fuzzy GARCH models for conditional density estimation

In this work we introduce a new flexible fuzzy GARCH model for conditional density estimation. The model combines two different types of uncertainty, namely fuzziness or linguistic vagueness, and probabilistic uncertainty. The probabilistic uncertainty is modeled through a GARCH model while the fuzziness or linguistic vagueness is present in the antecedent and combination of the rule base system. The fuzzy GARCH model under study allows for a linguistic interpretation of the gradual changes in the output density, providing a simple understanding of the process. Such a system can capture different properties of data, such as fat tails, skewness and multimodality in one single model. This type of models can be useful in many fields such as macroeconomic analysis, quantitative finance and risk management. The relation to existing similar models is discussed, while the properties, interpretation and estimation of the proposed model are provided. The model performance is illustrated in simulated time series data exhibiting complex behavior and a real data application of volatility forecasting for the S&P 500 daily returns series

Representation of Multiple Body Parts in the Missing-Hand Territory of Congenital One-Handers.

Individuals born without one hand (congenital one-handers) provide a unique model for understanding the relationship between focal reorganization in the sensorimotor cortex and everyday behavior. We previously reported that the missing hand\u27s territory of one-handers becomes utilized by its cortical neighbor (residual arm representation), depending on residual arm usage in daily life to substitute for the missing hand\u27s function [1, 2]. However, the repertoire of compensatory behaviors may involve utilization of other body parts that do not cortically neighbor the hand territory. Accordingly, the pattern of brain reorganization may be more extensive [3]. Here we studied unconstrained compensatory strategies under ecological conditions in one-handers, as well as changes in activation, connectivity, and neurochemical profile in their missing hand\u27s cortical territory. We found that compensatory behaviors in one-handers involved multiple body parts (residual arm, lips, and feet). This diversified compensatory profile was associated with large-scale cortical reorganization, regardless of cortical proximity to the hand territory. Representations of those body parts used to substitute hand function all mapped onto the cortical territory of the missing hand, as evidenced by task-based and resting-state fMRI. The missing-hand territory also exhibited reduced GABA levels, suggesting a reduction in connectional selectivity to enable the expression of diverse cortical inputs. Because the same body parts used for compensatory purposes are those showing increased representation in the missing hand\u27s territory, we suggest that the typical hand territory may not necessarily represent the hand per se, but rather any other body part that shares the functionality of the missing hand [4]

Forest biodiversity, carbon sequestration, and wood production: modeling synergies and trade-offs for ten forest landscapes across Europe

Original ResearchEurope’s forests provide vital habitat for biodiversity and essential ecosystem services whose provision must be sustained or enhanced over the coming century. However, the potential to secure or increase forest ecosystem services, while securing the habitat requirements of taxa remains unclear, especially within the context of uncertain climate and socio-economic developments. To tease out the associated trade-offs and synergies, we used 10 case study landscapes within nine countries throughout Europe. Starting with the current status of the forests in the case study landscapes, we simulated forest development 100 years into the future. Simulations were embedded in three combined climate and socio-economic frame scenarios based on global and European policies which varied in their climate change mitigation efficiency. Scenarios were translated into country specific projections of climate variables, and resultant demands for wood products. Forest management regimes were projected to vary in response to these scenarios at local scales. The specific combinations of alternative forest management practices were based on parallel research and input from local forest stakeholders. For each case study, a specific forest growth simulator was used. In general, the climate scenarios applied did not cause fundamentally different ecosystem service outputs at the case study level. Our results revealed almost no reduction in outcomes for biodiversity indicators with an increase in wood production, and in some cases synergistic results occurred when diversity was actively promoted as part of the management concept. Net carbon uptake was not strongly correlated with biodiversity, indicating that biodiversity-friendly forest management doesn’t need to curtail carbon sequestration. Notably, we obtained heterogeneous results for the relation between sustainable wood production and net carbon uptake. Most scenarios resulted in a more or less reduced net carbon uptake over the long term, often due to stand age class distribution shifts. Levels of sustainable wood production varied widely during the simulation period, from significant increases (Sweden, Lithuania) to minor changes (Slovakia, Turkey) and slight decreases (Ireland, Netherlands). We place our results within the larger context of European forest policy and the challenges of simulating and contrasting forest biodiversity and the ecosystem services that societies depend on outcomes for biodiversity indicators with an increase in wood production, and in some cases synergistic results occurred when diversity was actively promoted as part of the management concept. Net carbon uptake was not strongly correlated with biodiversity, indicating that biodiversity-friendly forest management doesn’t need to curtail carbon sequestration. Notably, we obtained heterogeneous results for the relation between sustainable wood production and net carbon uptake. Most scenarios resulted in a more or less reduced net carbon uptake over the long term, often due to stand age class distribution shifts. Levels of sustainable wood production varied widely during the simulation period, from significant increases (Sweden, Lithuania) to minor changes (Slovakia, Turkey) and slight decreases (Ireland, Netherlands). We place our results within the larger context of European forest policy and the challenges of simulating and contrasting forest biodiversity and the ecosystem services that societies depend oninfo:eu-repo/semantics/publishedVersio

Elevated Pontine and Putamenal GABA Levels in Mild-Moderate Parkinson Disease Detected by 7 Tesla Proton MRS

Background: Parkinson disease (PD) is characterized by the degeneration of nigrostriatal dopaminergic neurons. However, postmortem evidence indicates that the pathology of lower brainstem regions, such as the pons and medulla, precedes nigral involvement. Consistently, pontomedullary damage was implicated by structural and PET imaging in early PD. Neurochemical correlates of this early pathological involvement in PD are unknown. Methodology/Principal Finding: To map biochemical alterations in the brains of individuals with mild-moderate PD we quantified neurochemical profiles of the pons, putamen and substantia nigra by 7 tesla (T) proton magnetic resonance spectroscopy. Thirteen individuals with idiopathic PD (Hoehn & Yahr stage 2) and 12 age- and gender-matched healthy volunteers participated in the study. c-Aminobutyric acid (GABA) concentrations in the pons and putamen were significantly higher in patients (N = 11, off medications) than controls (N = 11, p,0.001 for pons and p,0.05 for putamen). The GABA elevation was more pronounced in the pons (64%) than in the putamen (32%). No other neurochemical differences were observed between patients and controls. Conclusion/Significance: The GABA elevation in the putamen is consistent with prior postmortem findings in patients with PD, as well as with in vivo observations in a rodent model of PD, while the GABA finding in the pons is novel. The more significant GABA elevation in the pons relative to the putamen is consistent with earlier pathological involvement of th

Brain glutamate in anorexia nervosa: a magnetic resonance spectroscopy case control study at 7 Tesla

RATIONALE: Anorexia nervosa (AN) is a serious psychiatric disorder with high morbidity and mortality. There are no established pharmacological treatments and the neurobiology of the condition is poorly understood. Previous studies using magnetic resonance spectroscopy (MRS) have shown that AN may be associated with reductions in indices of brain glutamate; however, at conventional field strengths (≤3 T), it is difficult to separate glutamate from its precursor and metabolite, glutamine. OBJECTIVES: The objective of the present study was to use high field (7 T) MRS to measure concentrations of glutamate, in three separate brain voxels, in women with AN. METHODS: We studied 13 female participants with AN and 12 healthy female controls who underwent MRS scanning at 7 T with voxels placed in anterior cingulate cortex, occipital cortex and putamen. Neurometabolites were calculated using the unsuppressed water signal as a reference and corrected for individual cerebrospinal fluid concentration in the voxel. RESULTS: We found that participants with AN had significantly lower concentrations of glutamate in all three voxels (mean reduction 8%, p = 0.002) but glutamine levels were not altered. Concentrations of N-acetylaspartate, creatine, GABA and glutathione were also unchanged. However, inositol was lower in AN participants in anterior cingulate (p = 0.022) and occipital cortex (p = 0.002). CONCLUSIONS: Women with AN apparently have widespread reductions in brain glutamate. Further work will be needed to assess if this change has pathophysiological relevance or whether it is a consequence of the many physical changes produced in AN by food restriction

A translation technique: Dimensionless ratings and conversion factors between ISO and AGMA gear standards

American Society of Mechanical Engineers (ASME)ASME 2016 International Mechanical Engineering Congress and Exposition, IMECE 2016 --11 November 2016 through 17 November 2016 -- --ISO and AGMA Standards are the most commonly used accurate approaches while designing a gear. But the most important gear design outputs that are module (m) and face width (b) are obtained from both of the approaches always differ from each other even under the same input parameters. Therefore, gear designers require detailed knowledge on the relative comparison of design outputs including cost. And a translation technique using conversion factors in between the standards are demanded as a stated need in the literature. Hence, this paper firstly obtains dimensionless gear rating numbers (GRi) to rate the design results of spur gears determined from both ISO 6336 and ANSI/AGMA 2101-D04 Standards, and then derives correlation equations to generate dimensionless conversion factors (CFs) to convert the design results obtained from ISO to AGMA. The CFs allow designers to move from one standard to another very easily. This enables engineering students and designers to meet the ever changing needs of global market. Copyright © 2016 by ASME

Mechanical engineering and issues on teaching mechanical engineering design in Turkey

Students with relatively low affinity and/or weak ability for science and mathematics have been presently acknowledged into Mechanical Engineering (ME) departments around the world. This has resulted in apparent lowering of fully competent graduate engineers, due to insufficient comprehension and its concomitant cognitive issues. Now, the complexity and the demand of ME education have been extremely unbalanced with recruited students. This conflict between the education process and less knowledgeable students has been adequately acknowledged, but remedies for this global issue are not yet available. This is no longer sustainable. The paper gives insight into (individual and combined) plausible reasons for fewer fully competent graduate engineers, taking the specific case study in Turkey. It proposes a generic approach, which can be extended to courses of any university/degree subject. Findings on student learning are provided using a hierarchical decomposition. A proposed remedy for this issue has been thoroughly evaluated, and accountability measures, qualitative data and a survey has been conducted for the ME design course taught in Turkey. The findings indicate that the new recruits are not fully to blame for the conflict, because there have also been other reasons for the issues within teaching. It identified multiple instances of the reasons such as unnecessary complexity of textbooks, unsolved contradictions even between the technical component design standards and etc. If these are considered by educators, this will help to reduce the perceived degree of teaching difficulty, and have a positive effect on the quality of graduates. It may even assist in attracting higher ability students into ME. © 2017, Springer Science+Business Media Dordrecht

Introducing gear ratings and AGMA conversion factors for the steel spur gear design under bending fatigue

The design approaches are not rated for gear tooth volume, the designers are not aware of the loss or gain on the cost, and failure or success of the design. This study provides a novel method to rate and convert textbook gear design approaches into ANSI/AGMA standard. The steel pinions with lowest and highest strengths covering minimum and maximum strengths available for the gear design meshing with cast iron gear were used in order to ensure that the method presented is generic. The method relies on obtaining design data (module m (mm) and face width F (mm)) for the most common design approaches considering bending fatigue. The gear design approaches are rated for the loss or gain using dimensionless geometric rating numbers, and then dimensionless conversion factors are obtained. Mean values of conversion factors independent of input power for the desired speed ratio are used to derive correlation equations for converting the design results of the selected approach to ANSI/AGMA standard. The method verified by case studies is generic and applicable to any gear design approach. Now, the most commonly used spur gear design approaches are rated by considering the gear volume. Furthermore, m and F obtained from the easiest textbook design approaches can be easily converted into the most accurate but more complicated, challenging and time-consuming ANSI/AGMA standard with minimum effort and error. It does not only allow saving time and resources but also provides safer and reliable designs for designers who are not bound to use a specific gear standard. © Carl Hanser Verlag, München

Effect of post-curing heat treatment on mechanical properties of fiber reinforced polymer (FRP) composites

Fiber reinforced polymer (FRP) composites have significant potential for applications in many engineering fields in place of metallic materials, due to their low density, high strength to weight ratio, high stiffness, better corrosion resistance and durability. The fabrication of these composites requires careful design and appropriate process developments to improve the mechanical properties. This study aims to investigate the effect of the post-cure heat treatment on the tensile and impact toughness of FRP composites. FRP composites were fabricated by using woven carbon and glass fiber fabric plies and their respective hybrid laminates. Hand lay-up using vacuum bagging method was used for manufacturing the laminated composites. After curing, the specimens were subjected to the post-curing process at temperatures of 25, 62.5 and 100°C for 1 hour. Impact toughness and tensile strength of post-cured FRP composite specimens were investigated by the Charpy impact test and tensile test, respectively. Statistical analyses were also performed to compare the effect of both, the post-curing temperature and the FRP type, on the mechanical properties of composite specimens by using two-way ANOVA analysis. The results showed that post-curing has a favorable effect on energy absorption capacity and tensile properties of FRP. © 2017 Carl Hanser Verlag, München