Neural Representations of Visual Motion Processing in the Human Brain Using Laminar Imaging at 9.4 Tesla

During natural behavior, much of the motion signal falling into our eyes is due to our own movements. Therefore, in order to correctly perceive motion in our environment, it is important to parse visual motion signals into those caused by self-motion such as eye- or head-movements and those caused by external motion. Neural mechanisms underlying this task, which are also required to allow for a stable perception of the world during pursuit eye movements, are not fully understood. Both, perceptual stability as well as perception of real-world (i.e. objective) motion are the product of integration between motion signals on the retina and efference copies of eye movements. The central aim of this thesis is to examine whether different levels of cortical depth or distinct columnar structures of visual motion regions are differentially involved in disentangling signals related to self-motion, objective, or object motion. Based on previous studies reporting segregated populations of voxels in high level visual areas such as V3A, V6, and MST responding predominantly to either retinal or extra- retinal (‘real’) motion, we speculated such voxels to reside within laminar or columnar functional units. We used ultra-high field (9.4T) fMRI along with an experimental paradigm that independently manipulated retinal and extra-retinal motion signals (smooth pursuit) while controlling for effects of eye-movements, to investigate whether processing of real world motion in human V5/MT, putative MST (pMST), and V1 is associated to differential laminar signal intensities. We also examined motion integration across cortical depths in human motion areas V3A and V6 that have strong objective motion responses. We found a unique, condition specific laminar profile in human area V6, showing reduced mid-layer responses for retinal motion only, suggestive of an inhibitory retinal contribution to motion integration in mid layers or alternatively an excitatory contribution in deep and superficial layers. We also found evidence indicating that in V5/MT and pMST, processing related to retinal, objective, and pursuit motion are either integrated or colocalized at the scale of our resolution. In contrast, in V1, independent functional processes seem to be driving the response to retinal and objective motion on the one hand, and to pursuit signals on the other. The lack of differential signals across depth in these regions suggests either that a columnar rather than laminar segregation governs these functions in these areas, or that the methods used were unable to detect differential neural laminar processing. Furthermore, the thesis provides a thorough analysis of the relevant technical modalities used for data acquisition and data analysis at ultra-high field in the context of laminar fMRI. Relying on our technical implementations we were able to conduct two high-resolution fMRI experiments that helped us to further investigate the laminar organization of self-induced and externally induced motion cues in human high-level visual areas and to form speculations about the site and the mechanisms of their integration

Estimating Environmental Efficiency of the Agricultural Sector

Economic activity is associated with the incidence of some adverse environmental consequences such as global warming, climate change and acid rain. Therefore, it is necessary to analyze these impacts using economic-environmental theories. On this base, it is necessary to correct the efficiency models by combining good and bad outputs in efficiency calculations. In this study, environmental efficiency of agricultural sector is calculated by including data of five pollutants ( ،NOX ، ،CO،  during 1373-1390 using Data Envelopment Analysis. The results show that the efficiency scores by including bad outputs (pollutants) less than the efficiency without the inclusion of bad outputs. By inclusion of bad outputs in the process of calculating efficiency, the average efficiency has fallen from 0.98 to 0.72. This suggests that environmental conditions have significant impact in efficiency measures. On this base, it is proposed to include good and bad outputs in efficiency measures for achieving a realistic view of the situation of firms

The importance of pediatric cancer registries in childhood cancer control

Cancers in children, as the major cause of pediatric deaths, account for one percent of all cancers. Cancer control program is intended to diminish occurrence, morbidity and mortality and to improve the life quality of people with cancer. A key element of any reasonable cancer control program is cancer registry. A registry which serves as the backbone for any treatment plan in childhood oncology. Given the importance of pediatric cancer, the present paper explores the importance of pediatric cancer registry in childhood cancer control

Underground hydrogen storage: a review

: Large-scale underground storage of hydrogen gas is expected to play a key role in the energy transition and in near future renewable energy systems. Despite this potential, experience in underground hydrogenstorage remains limited. This work critically reviews the most important elements of this crucial technology,including hydrogen properties and their significance for subsurface operations, sources for hydrogen and historical hydrogen storage operations, to set the state of the art. The cyclical nature of hydrogen storage operationswill produce pressure and stress changes within the reservoir that could affect the integrity of the well, the reservoir, the caprock and the entire subsurface storage complex. To minimize geomechanical leakage risks andoptimize the storage operation it is crucial to understand the pressure and stress history of the storage site, tooptimize well locations to manage pressure and to identify the reservoir-specific cushion gas to working gasratio. Finally, we outline the major scientific and operational challenges required to ensure the safe and efficientdeployment of underground hydrogen storage at a large scale

Comparing the Effect of Eutectic Mixture of Lidocaine and Prilocaine and Capsaicin on Improving Ischemic Random Skin Flaps: An Animal Model

Background: Ischemia of skin flaps is an important complication in reconstructive surgery. This study evaluated the effectiveness of eutectic mixture of lidocaine and prilocaine (EMLA) and capsaicin on improving flap survival.Methods: A number of 39 white-albino male rats were divided randomly into three groups: EMLA, capsaicin, and control groups. A standard rectangular, distally based dorsal random pattern skin flap was elevated on each rat. Intraperitoneal cefazolin was administered to prevent infection. No pharmaceutical agent was administered for the control group except for pure Vaseline cream. In EMLA group, EMLA cream was administrated daily after surgery for 10 days. In capsaicin group, capsaicin cream was rubbed on the flap surface daily. The rats were evaluated 10 days after the operation for viable and necrotic portions of flaps.Results: The mean values of necrosis in the flaps were 603.33 ± 116.00 mm2, 665.00 ± 220.26 mm2, and 920.00 ± 247.31 mm2 in the EMLA, capsaicin and control groups, respectively. Both EMLA and capsaicin were effective on flap survival significantly (P = 0.002 and P = 0.011, respectively). Despite advantages, EMLA was not significantly better than capsaicin (P = 0.739).Conclusions: EMLA and capsaicin are effective pharmaceutical agents that significantly increase the viability of random skin flaps in rats. They can be added to other vasoactive topical agents to reach better results and be used as a medical workhorse in reconstructive wards

Developing a Conceptual Model of Cultural Policy-making in District 8 Payame Noor Universities based on Piety

The present study aimed to provide a conceptual model of cultural policy-making in Payame Noor universities in District 8 based on piety and virtue. In this study, the components of cultural policy based on piety were first identified through exploratory studies and surveys of knowledge-aware experts using the Delphi technique, and then these factors were tested in the form of a model designed in the statistical population. The statistical population of the study was 30 experts to test the model and to measure the research variables according to the managers of District 8 Payame Noor University; the head of cultural affairs of the university and clerics and professors of Islamic education department of Payame Noor Universities District 8 were used, which were 110 individuals. Due to the limited statistical population, the census method was used. The present study is a descriptive-correlational research that has been done by survey method. Furthermore, this research is development-applied in terms of purpose. The data collection method in this study is a combination of library and field studies and the tools of data collection are review of documents, interviews and questionnaires, which confirmed the validity and reliability of the questionnaires. In order to analyze the data, descriptive statistics (types of indicators, statistical tables and graphs) and inferential statistics (structural equation modeling) have been used. The research findings, while confirming the proposed model of research, showed that piety and its components: God-centeredness and monotheism, promoting the need to obey divine sovereignty, expediency in Islamic culture and meritocracy (Imam Ali's biography) have a positive and significant effect on cultural planning. At the end, research suggestions were presented

New Insight into Mechanical and Thermal Properties of Geomaterials: A Molecular Dynamics Study

Due to the recent dramatic increase in computing power available for mathematical modeling and simulation, modern numerical methods play an important role in the analysis of various structural types. Molecular dynamics (MD) and finite element (FE) analysis are one of the most well-developed and popular applications of numerical methods.Silicates are of considerable technological importance because of forming more than 90% of the minerals in the earth’s crust. In addition, the quartz mineral is the major ingredient of silicate particles. In this regard, no published literature has yet investigated the effect of rock particles' crystal structure on their constitutive behavior in nanoscale to explore the effect of particles and fabric on the constitutive behavior of rocks such as crack growth, creep, and fatigue. Molecular dynamics (MD) simulation strives to reinforce experimental predictions and provide insight into the atomistic processes that control examined phenomena as a support of the experimental work and also as a method to fill out the gaps left by laboratory tests. In this dissertation, the analysis of thermo-mechanical properties and the fracture mechanism of crystalline alpha quartz are performed over a wide range of temperatures using MD simulations. For this purpose, a well-known molecular dynamics package (LAMMPS) is employed to investigate the fracture mechanics and crack propagation behavior of 2-D and 3-D crystalline alpha quartz at the atomistic scale. By creating an edge and central crack in the samples and applying uniaxial tensile stress on the material, crack propagation is examined. Moreover, stress-strain behavior of the material, Young’s modulus, fracture toughness, and the effect of grain boundary are identified for different strain rates and crack sizes. According to the results, crystalline alpha quartz shows an anisotropic behavior at the nanoscale, and this anisotropy is regulated by a complicated mechanical process. This knowledge could be utilized to control the crack path and fracture toughness while designing in laboratory experiments and field tests. Besides mechanical properties, crystalline quartz's thermal properties, including thermal conductivity and thermal expansion coefficient, are predicted by using both equilibrium and non-equilibrium molecular dynamics simulations. Also, to explore the effect of forcefields on the results, several interatomic potentials are employed, and the findings are compared.Release after 12/21/202

Molecular dynamics simulation of edge crack propagation in single crystalline alpha quartz

Edge crack propagation of single-crystalline alpha quartz under mode I loading condition was investigated using a molecular dynamics simulation. Five different crack lengths are used to analyze the effects of crack length on each sample's crack growth behavior. The effect of crack length was studied in terms of the material's stress-strain curve, strain energy, fracture toughness, atomic analysis of crack propagation, and crack opening deformation. The results revealed that during tensile loading, the pre-cracked crystalline quartz samples are fractured in a brittle approach. The fracture stress in the pre-cracked sample (40 Å length) is dropped about 70% compared to pristine quartz. Moreover, the effect of loading velocity on the mechanical properties is investigated. According to the findings, maximum stress rises by enhancing the loading velocity, and fracture toughness improves. The fracture surface energy of the single crystalline alpha quartz is calculated, and based on the results, there is a good agreement with experimental data.24 month embargo; available online 21 November 2021This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]