Added benefits of computer-assisted analysis of Hematoxylin-Eosin stained breast histopathological digital slides

This thesis aims at determining if computer-assisted analysis can be used to better understand pathologists’ perception of mitotic figures on Hematoxylin-Eosin (HE) stained breast histopathological digital slides. It also explores the feasibility of reproducible histologic nuclear atypia scoring by incorporating computer-assisted analysis to cytological scores given by a pathologist. In addition, this thesis investigates the possibility of computer-assisted diagnosis for categorizing HE breast images into different subtypes of cancer or benign masses. In the first study, a data set of 453 mitoses and 265 miscounted non-mitoses within breast cancer digital slides were considered. Different features were extracted from the objects in different channels of eight colour spaces. The findings from the first research study suggested that computer-aided image analysis can provide a better understanding of image-related features related to discrepancies among pathologists in recognition of mitoses. Two tasks done routinely by the pathologists are making diagnosis and grading the breast cancer. In the second study, a new tool for reproducible nuclear atypia scoring in breast cancer histological images was proposed. The third study proposed and tested MuDeRN (MUlti-category classification of breast histopathological image using DEep Residual Networks), which is a framework for classifying hematoxylin-eosin stained breast digital slides either as benign or cancer, and then categorizing cancer and benign cases into four different subtypes each. The studies indicated that computer-assisted analysis can aid in both nuclear grading (COMPASS) and breast cancer diagnosis (MuDeRN). The results could be used to improve current status of breast cancer prognosis estimation through reducing the inter-pathologist disagreement in counting mitotic figures and reproducible nuclear grading. It can also improve providing a second opinion to the pathologist for making a diagnosis

Leak-off test (LOT) models combining wellbore and near-wellbore mechanical and thermal behaviors

Considerable efforts to model leak-off test (LOT) and leak-off behaviors have been carried out in the past. Altun presented a model to estimate leak-off volume by dividing the wellbore system into four sub-systems: mud compression, casing expansion, fluid leakage, and borehole expansion (Altun 2001). The volume response from each sub-system is then combined to represent the total volume pumped during a LOT. Most existing leak-off models do not account for mechanical behavior of cement and rock formations around the wellbore. While their compressibilities are small, the cement and rock formation volume changes can be significant. In this research, a mechanical expansion model has been developed, based on a linearly elastic, concentric cylinder theory developed by Norris (Norris 2003). The model is an extension of Lamé equations for multi concentric cylinders and assumes the horizontal stresses on the system’s boundary are applied equally in all directions, i.e., the horizontal, far-field stresses around the system are isotropic. The resulting model simulates the compound radial displacements of casing, cement, and formation along the cased hole, based on pressures inside the wellbore and in the far-field stress region. The volume generated from concentric cylinder expansion is then combined with Altun’s model to simulate the total volume pumped during a LOT. One use of the model is the estimation of minimum horizontal far field stress. Since the model consists of concentric cylinders, the pressure on the outside boundary can approximate the minimum horizontal far field stress, which in turn is related to overburden pressure. The pressure inside the most inner cylinder is calculated from known mud weight. With an initial estimation for the far field stress and iterative methods, the minimum horizontal stress can be estimated. The developed models were then applied to field LOT data from Gulf of Mexico. The results show that leak-off volume along the cased hole should be analyzed as a compound expansion of casing, cement, and formation.Petroleum and Geosystems Engineerin

High Power Gain Guided Index Antiguided Fiber Lasers and Amplifiers

Abstract Increasing the core size of high-power fiber lasers and amplifiers is highly desired in order to mitigate the unwanted nonlinear optical effects and raise the optical damage threshold. If the core size of conventional index-guided (IG) optical fibers increases, the fiber will become multimode, because it is very difficult to control and fine-tune the index step between the core and cladding to satisfy the single mode condition. Siegman proposed Gain-guided index-antiguided (GG-IAG) fibers as a possible platform for ultra-large-core single-mode operation for lasers and amplifiers. In this thesis, the beam-quality factor M2 for the fundamental LP01 mode of a step-index fiber with finite and infinite cladding diameter is calculated in the presence of gain as a function of the complex generalized V number. The numerical results agree with analytical work that obtained in our group. It is shown that the M2 value of a single-mode gain-guided fiber laser can be arbitrarily large. The results are important for the interpretation of the beam-quality measurements in recent experiments on single-mode gain-guided fiber lasers. It is also shown that the conventional infinite cladding diameter approximation cannot be used for index-antiguided gain-guided fibers, and the rigorous analysis is required for accurate prediction of the beam quality factor, as reported in recent experimental measurements. We also highlight the key reasons behind the poor power efficiency observed in multiple experiments in gain guided index-antiguided (GG-IAG) fiber amplifiers and lasers. We show that by properly designing the fiber geometrical characteristics, it is possible to considerably improve the power efficiency of GG-IAG fiber amplifiers in end-pumping schemes

Clearing the confusion about self-directed learning and self-regulated learning

Self-Directed Learning (SDL) and SelfRegulated Learning (SRL) are often used without a clear distinction, leading to confusion in understanding and the use of inappropriate measurement tools. SDL is a general approach to learning and can be identified using ‘aptitude’ questionnaires but SRL is a dynamic and context specific learning process and requires ‘event’ measures, such as microanalysis. These differences have implications for research and remediation

Relationship between Weather Components in Polluted Days and the Number Of Hospitalization Due to Cardiovascular Diseases

Aims: Air is the combination of atmospheric components or physical conditions of the current atmosphere in a certain place and a certain time. The aim of this study was to assess the relationship between weather components, air atmospheric pollutants and the number of individuals that were hospitalized due to cardiovascular diseases in polluted days. Instrument & Methods: In this descriptive study during 2010 to 2013, the weather parameters in ground and upper levels of Isfahan City, Iran, weather stations were studied and air quality data were collected from 11 different points of the city. The number of cardiovascular patient that were hospitalized was determined by collecting the data of medical record department of 3 hospitals of Isfahan City, Iran; Shahid Chamran, Al-Zahra, and Ali-Asghar. Data were analyzed by SPSS 19 software using Pearson correlation. Findings: There were significant correlations between the number of hospitalizations and minimum temperature (r=0.943; p=0.0001), maximum temperature (r=0.973; p=0.0001), average temperature (r=-0.069; p=0.013), rainfall (r=-0.326; p=0.0001), humidity (r=-0.326; p=0.0001), air pressure (r=0.257; p=0.0001), and wind speed (r=-0.011; p=0.021). There was a significant difference between the average numbers of hospitalizations due to cardiovascular diseases according to the range of AQI. Regarding the air pollutant parameters, the only significant relation was observed for PM10 (p=0.004) and other factors showed no significant relation (p<0.05) to the numbers of hospitalizations. Conclusion: The number of hospitalizations due to cardiovascular diseases is just affected by the PM10 factor of air pollution

Optimized site selection for a health themed recreational city

Industrial cities have many issues including people working long hours, environmental pollution, the aging of the population, and consumers demanding to have leisure, recreation and outdoor recreation opportunities. Constructing a place for healthy outdoor recreation can address some of those needs. The primary objective of this study is to test this concept by identifying and prioritizing the potential health recreational sites using Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) in Isfahan City, Iran. This study identifies the following factors as indicators of suitability within a health recreational city: land prices, road system, capitation, distance from industrial areas, the Air Quality Index, distance from a river, recreational sites, access to public transport stations, and distance to medical care. These factors were selected based on the professional expert’s opinions developed through the Delphi method. AHP was effectively used in this study to calculate the details of the factors and class weights. GIS (v10.2), which plays a crucial role in urban planning, was employed. The methodology proposed was useful in identifying health recreational sites by linking the criteria deemed important with the actual resources of the province

Thermoporoelastic wellbore stability model with local thermal non-equilibrium

Wellbore stability is a key challenge for the exploration and production industry since it adds a great deal of additional cost. Traditional wellbore stability models such as elastic and poroelastic models are not sufficient in modeling the stability and produce erroneous results since they consider an isothermal condition. The industry also overlooks the potential impact of thermal effects on wellbore stability and utilizes a trivial approach in modeling the thermal stresses. During the drilling phase, the drilling fluid temperature is different from the formation temperature due to geothermal gradient and circulation of the mud inside the wellbore. Therefore, the assumption of an isothermal condition will not predict the correct wellbore stability condition, especially for high pressure and high temperature wells. The knowledge of in-situ stresses, breakout, and breakdown is vital to oil and gas industry, affecting wellbore stability, well location, production rate, completion and casing designs. Determination of breakout pressure helps avoid wellbore enlargement and shear failure, while, breakdown pressure aids in knowledge of the formation fracture gradient and the limits for the drilling mud weight window. Estimations of breakout and breakdown gradients can substantially be affected by the induced thermal stresses that occur during the drilling phase of a wellbore. The fully coupled thermoporoelastic model developed in this dissertation reveals the importance of induced thermal stress in stress resolution and wellbore stability evaluation. It produces reasonable results compared to uncoupled models and models with isothermal assumption. Most existing thermoporoelastic models utilize the assumption of local thermal equilibrium. The local thermal equilibrium assumption ignores additional pore and thermal stresses in the porous medium caused by temperature variations of the fluid and solid phases. This dissertation investigates the effect of thermal stresses on stress resolution around a wellbore and wellbore stability in a fully coupled condition with consideration of local thermal non-equilibrium heat transfer. The model is applicable for any wellbore trajectories in low and high permeable formations with consideration of conductive and convective heat transfersPetroleum and Geosystems Engineerin

Leadership behaviors in health care action teams: a systematized review

Background: Effective leadership is critical for the performance of health care teams and their intended outcomes for patient care. Given that team leadership is a modifiable and teachable skill, there is a need for a better understanding of this multidimensional behavior to inform future leadership training for health care action (HCA) teams. This systematized review identifies reported observed leadership behaviors in HCA teams, defined as interdisciplinary teams which complete vital tasks in complex, time-pressured, and dynamic situations. Methods: We searched CINAHL, MEDLINE, Scopus, PsycINFO, and Web of Science for peer-reviewed, English language articles using single and combinations of keywords including leadership, health care action team, and teamwork, individually. We included articles published until June 2021 without any specific beginning date. Results: From 242 records, 13 articles were included in the review. We categorized our findings of team leadership behaviors in HCAs based on an existing framework of three dimensions: transition processes, action processes, and interpersonal skills. The most-reported behaviors for transition processes were encouraging team members’ input, (re)assessing the team’s situation, and confirming team members’ understandings. The action processes dimension consisted of behaviors that included monitoring the progress of the patient, managing resources, asking for help when needed, coaching/supervising, and assisting team members as needed. Finally, closed-loop communication and facilitating team members speaking up behaviors were categorized as interpersonal skills. Conclusion: Although team leadership has been an area of focus in the field of health professions education, little attention has been paid to identifying the observable behaviors of effective team leaders in an HCA team. The study identified several new essential team leadership behaviors that had not been previously described, including seeking feedback, shared decision making, and aspects of interpersonal communication. The findings can inform educators in planning and implementing strategies to enhance HCA team leadership training, with the ultimate potential to improve health care

On the Beam Profile and Beam Quality of Gain-Guided Index-Antiguided Fibers with Finite Cladding Boundary

The beam quality factor $M^2$ for the fundamental LP01 mode of a step-index fiber with a finite cladding diameter is calculated in the presence of gain, in a closed form, as a function of the complex generalized V-number. It is shown that the conventional infinite cladding diameter approximation cannot be used for index-antiguided gain-guided fibers, and the rigorous analysis presented in this paper is required for accurate prediction of the beam quality factor, as reported in recent experimental measurements