Adaptive Re-Segmentation Strategies for Accurate Bright Field Cell Tracking

Understanding complex interactions in cellular systems requires accurate tracking of individual cells observed in microscopic image sequence and acquired from multi-day in vitro experiments. To be effective, methods must follow each cell through the whole experimental sequence to recognize significant phenotypic transitions, such as mitosis, chemotaxis, apoptosis, and cell/cell interactions, and to detect the effect of cell treatments. However, high accuracy long-range cell tracking is difficult because the collection and detection of cells in images is error-prone, and single error in a one frame can cause a tracked cell to be lost. Detection of cells is especially difficult when using bright field microscopy images wherein the contrast difference between the cells and the background is very low. This work introduces a new method that automatically identifies and then corrects tracking errors using a combination of combinatorial registration, flow constraints, and image segmentation repair

Accelerating regional trade integration in Africa through regional value chains: A SADC perspective

Regional integration has been a key ambition, vision and standing agenda of the African continent for the past two decades. The recent signing of the Africa Continental Free Trade Agreement (AfCFTA) (signed by 54 of the 55 members of the African Union as of July 2019) brings to the fore the urgent need to accelerate the implementation of what has been thus far an elongated period of planning and discussion. One of the key mandates of the AfCFTA is to ensure acceleration of intra-African trade and boost Africa's trading position in the global market by strengthening Africa's common voice and policy space in global trade negotiations (African Union, 2018). Intra-regional trade can be considered as a quick avenue for the continent and its respective Regional Economic Communities (RECs) such as the Southern African Development Community (SADC), to implement this agenda by leveraging collective resources and opportunities such as increased focus on the establishment of regional value chains (RVCs). Currently, the SADC region has been at the forefront of driving regional trade integration (RTI) in the continent; however, intra-regional trade is still only but a fraction of the RECs total global trade, averaging 5-7% of total trade in 2015-2017. Because of the myriad of challenges in the region – including but not limited to the low rate of RTI, poor infrastructure, poor institutions, unstable political environments, and slow economic growth – RECs, let alone the continent as a whole, cannot take part in and capitalise on the opportunities from complex trade networks through global and regional value chains. Moreover, when African countries do participate in global value chains, they find themselves at the lower end of the value chain where it is harder to reap the benefits due to the unequal distributional effects of such trade activities. This study therefore examined the key factors that drive RTI, and sought to ascertain the relationship between regional value chains and regional trade integration. Lastly, the study aimed to uncover the contribution to economic growth of such trade activities. Thirteen SADC countries are observed over the period 2000-2017 using panel data analysis and various key estimation techniques to ensure robustness of the models used. The study finds that there are definitely key factors that drive regional trade integration in the REC that require increased focus from policy makers and trade activity participants as they have the potential to change the trajectory of the region and the continent's trade landscape. The study also indisputably finds a two-way relationship between RTI and RVCs, suggesting that if key aspects of these activities are addressed, this would lead to a mutual increase in iv these factors as they are highly complementary activities. Lastly, the study confirms the positive impact that RTI and RVCs would have on economic growth attributed to an increase in the level of productive economic trade activity thereby contributing to the gross domestic product (GDP) of countries as individuals and as a collective. The study therefore concludes that there should be more focus from policy makers and all key trade activity stakeholders on driving regional trade integration and participation in regional value chains as the benefits could prove highly rewarding to the SADC RECs and the continent as a whole. Such increased focus will ensure that the region is fully capitalising on the unique strengths of the African continent and driving collective growth and development

Application of binary logistic regression in credit scoring

Nowadays, demand for loan products is growing day by day. Also, loan applicants have become more demanding, than they were before. They want to receive the response from bank as soon as possible. In order to resist the growing competition banks develop new quantification techniques which accelerate and automate the decision making process. One of these techniques is credit scoring. Credit Scoring is one of the most widely used instruments which is applied by lenders decide whether to approve or reject the loan application. In this Master’s thesis an overview of credit scoring is given. The most essential objective of this thesis is to show the application of logistic regression in Credit score models. Other methods of credit scoring will also be noted, but not in extensive detail. The study ends with a practical application of logistic regression for a credit scoring model on real data of loan applicants

Unidentified Flying Objects: Implications on Global Peace and Security

Innumerable intricate perilous conundrums have swamped various states across the world threatening international peace and security in the 21st Century These threats to international peace and security range from arms proliferation both small and Weapons of Mass Destruction to terrorism striving in North Africa and the Middle East and intrastate group fights inter alia cyber threats among others These problems are and have been a menace to peaceful existence of states and the securitisation of individuals in the entire international milieu Most authors have written extensively from various windows on these problems which have been facing humanity and states have joined hands in countless multilateral efforts to combat some of these problems Conversely the issue of Unidentified Flying Objects has been snubbed in the international peace and security discourse in spite of the conceivable threats that these objects pose or may pose to humanity The subject of Unidentified Flying Objects has been contentious principally the existence of these unearth like objects despite evidence from various countries that reveal incidences of the manifestation of these unidentifiable humanoids In this way this research seeks to add to the distant voices that have warned states of another threat that could be more extreme than most of the sociopolitico economic and even environmental challenges that have engulfed nation-stations since the times of yore The central argument in the paper is that the continued presence of unidentified flying objects whether as projects of the major powers in the world or as aliens from other planets presents a problem which states should be prepared to decisively deal with in times of need For years unidentified flying objects have been seen around the world but their intention source and what really they are has not been determined and this is a foundation for concern apropos global peace and security The paper also focuses on providing p

The prevalence of recurrent ameloblastoma at the Wits oral health centre

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Dentistry, June 2018Abstract Background Ameloblastoma is a slow growing, locally invasive, benign tumour of odontogenic origin. Ameloblastoma is the most common odontogenic tumour with varying recurrence rates, depending on the adequacy of the tumour removal. A number of factors including inadequate removal of tumour have been associated with recurrence Aim The aim of the study was to determine the prevalence of recurrent ameloblastoma in patients treated at the Wits Oral Health Centre. Methods This study was a retrospective analysis of 246 records of patients diagnosed with ameloblastoma over a 24 year period (January 1992 to December 2015) in order to determine factors associated with recurrence. Descriptive statistics of mean, standard deviation, frequencies, percentages and proportions were used to summarize the data. Chi- squared and multivariate logistic regression was used to determine the association between the variables and recurrence associated with AMB. Results Males (49.6%) and females (50.4%) were equally affected with a mean age of 31 years (range 7-82 years). AMB affected the mandible (96%) more than the maxilla (4%). Multicystic AMB represented the majority (76.8%) of cases. Most AMB’s (92.7%) presented with bone perforation. Nineteen cases (7.7%) recurred, mostly in soft tissues, fifteen of which were treated radically and four conservatively. Fifteen (78.95%) recurrent AMB’s presented within 10 years of surgical treatment with the remainder (2, 1 and 1) presenting 13, 17 and 21 years post-treatment, respectively. AMB’s larger than 4cm in greatest diameter were associated with 84.21% of the recurrences. Multicystic AMB accounted for 84.21% of the recurrences. Conclusions This study is in agreement with most studies with regard to demographic data and clinicopathological features of AMB. Large multicystic AMB with soft tissue encroachment have a high propensity to recur even when treated by radical resection. Recurrence is a significant associated with histological margins and the surgical method of treatment.XL201

Perceptions of nurse educators in Limpopo Province regarding their empowerment

The purpose of this study was to describe the perceptions of nurse educators in Limpopo Province regarding their empowerment. The researcher conducted a quantitative descriptive-correlative research design to describe the perceptions of nurse educators in Limpopo Province regarding their empowerment. Laschinger's Integrated Model of Nurse/Patient Empowerment deduced from Kanter's Theory of Structural Power in organisations and Spreitzer's Psychological Empowerment Theory guided the construction of the data collection instrument. Data collection was carried out using a self-designed structured questionnaire. The population comprised all nurse educators in Nursing Education Institutions in Limpopo Province. The Ethics Committee of the Department of Health in Limpopo Province granted permission to conduct the research in the Limpopo Province. Non-probability convenience sampling was applied to obtain the participant sample for the study. The study shed light on important aspects of nurse educators' perception of their empowerment. The findings demonstrated that nurse educators perceived the concept of empowerment differently. The most incorrect perception of empowerment was that empowerment entailed paternalism rather than democratic (n=73; f=43;58.9%) and that it involved alienation rather than being inclusive, also at 58.9%. The total average scores were of concern to the researcher. The results of respondents' experience of structural empowerment varied as only 0.9%(f=1) did not indicate whether they agreed or disagreed that structural empowerment existed at the NEIs. 40.4% (f=44) indicated/agreed to have experienced psychological empowerment while 57.8% (f=63) have not experienced psychological empowerment. The findings related to association amongst the constructs indicated that gender was not associated with structural empowerment as well as psychological empowerment (p-value less than 0.05). There was no association between the highest qualification and structural empowerment (50.5% (f=55). However, 57% (f=63) agreed that there was an association between the highest qualification and psychological empowerment of respondents. The respondents disagreed that years of teaching experience (50.5% (f=55) was associated with structural empowerment, while 48.6% (f=53) believed it existed. The respondents indicated that no association existed between the campus they were placed at and structural empowerment (50.9% (f=55) while 57.8% (f=62) agreed that the campus placement was associated with structural empowerment as well as being associated with psychological empowerment at 56.5% (f=61). The discipline in which the nurse educators were teaching was not associated with either their structural empowerment (p=843 more than p=0.05) or their psychological empowerment at p=0.955 more than p=0.005). The respondents agreed that the discipline they taught was associated with their psychological empowerment at 55.9% (f=57); however, no statistically significant association existed at p-value 0.665 more than p-value 0.005. As the results indicated, the concept of empowerment yielded various perceptions of nurse educators. The results demonstrated the necessity to develop empowerment programmes for nurse educators at the NEIs.Maikemišetso a dinyakišiso tše e be e le go hlalosa maikutlo a bafahluši ba baoki mo Profentshing ya Limpopo mabapi le ka fao ba boning matlafatšo ya bona. Go šomišitšwe motheo was hlaloso-kamano go hwetša maikutlo a mafahluši ba baoki. Dinyakišišo di be di ithekgilwe ka kgopolo-kgolo ya Laschinger ya matlafatšo ya balwetši, a e tsere go tšwa kgopolong-kgolo ya Kanter ya matlafatšo mo mešomong le matlafatšo ya megopolo ya go ngwalwa ke Spreitzer. Dikgopolo-kgolo tše di šomišitšwe go aga/dira gore monyakišiši a kgone go hwetša maikutlo a mafahloši ba baoki mo kholetšheng ya baoki. Dinyakišišo tše di itheilwe godimo ga mafahloši ba baoki ka moka mo kholetšheng ya baoki ya profense ya Limpopo. Komiti ya maitshwaro a mabotse mo Lefapheng la Maphelo e file monyakišiši tumelelo ya go dira porotšeke ye. Porotšeke ye e laiditše seemo sa matlafatšo ya mafahluši ba baoki mo porofentsheng ya Limpopo. Dipoelo tša dinyakišišo tše di bontšhitše gore mafahluši ba baoki ma na le maikutlo a a fapaneng mabapi le matlafatšo ya bona. Seo se sa kgotsofatšeng ke gore bafahlušhi ba baoki ba (n=73; f=43;58.9%) ga ba laetša maikutlo a a nyakegang ka gore ba bontšhitše gore matlafatšo mo kholetšeng ya baoki ke kgateleo go na le gore ke temokerasi. Mafahluši ba 58.9% ba rile matlafatšo ke go bea motho thoko bakeng sa go dumela polelo ya maikutlo a lokologilego. Taba ye ke yona e tshwentsego monyakisisi. Dipoelo di bontšhitse gore palo ya bafahlušhi ba baoki e lego 0.9% (f=1) ga se e dumele goba go gana gore go na le matlafatšo mo ba šomago. Mafahluši ba 40.4% (f=44) ba bontshitše gore ba bone gore go na le matlafatšo ba mogopolo mola ba 57.8% (f=63) ba bontšhitše gore gab a ikwa ba matlafaditšwe mogopolong. Dipoelo di bontšha gape gore ga go na kamano magareng ga bong le matlafatšo ya mo mošomong. Gape, ga gona matlafatšo magareng ga go rutega le matlafatšo mo mošomong (50.5% (f=55). Ka go le lengwe, mafahluši ba baoki ba 57% (f=63) ba dumetše gore gona le kamano magareng ga go rutega le mafatšo ya mogopolo. Palo ba bona e lego (50.5% (f=55) e bontšhitše gore gona kamano ya matlafatšo le maitemogelo mola ba (48.6% (f=53) bas a kwane le kgopolo ya gore gona le kamanoHealth StudiesD. Litt. et Phil. (Health Studies

Estimation of Zimbabwean migration for the period 1992-2012

International migration is the movement of people across national boundaries, and it is an important mechanism for globalisation and economic development. However, in third world countries, it means a large proportion of the population leaving. It is hard to come by statistics on emigration due to the unavailability of sound administrative data systems that record the number of departures from the country. This research seeks to estimate the net number of Zimbabwean migrants for the period 1992 to 2012, by using census data from Zimbabwe and census data from the major receiving countries of Zimbabwean migrants (South Africa and the UK) and data from the Department of Economic and Social Affairs (United Nations 2017e) for other receiving countries. The research also explores alternative estimates of the net number of Zimbabwean migrants implied by other data sources and how they compare to the estimates derived by this research. This research found that the number of Zimbabweans that left the country during the period 1992 to 2012, is between 761,682 and 1,462,620. Furthermore, the results of this research suggest that Zimbabwe is a net emigration country and the net number of Zimbabwean decreased in the second intercensal period compared to the first intercensal period. In addition, the estimates derived in this research show that migration is concentrated in the economically active age groups. Also, a notable increase in the number of female migrants is observed. A comparison of estimates derived in this study to estimates by other data sources indicated that our estimates for the net number of Zimbabwean migrants for the two intercensal periods are plausible

Efficient Multi-Robot Coverage of a Known Environment

This paper addresses the complete area coverage problem of a known environment by multiple-robots. Complete area coverage is the problem of moving an end-effector over all available space while avoiding existing obstacles. In such tasks, using multiple robots can increase the efficiency of the area coverage in terms of minimizing the operational time and increase the robustness in the face of robot attrition. Unfortunately, the problem of finding an optimal solution for such an area coverage problem with multiple robots is known to be NP-complete. In this paper we present two approximation heuristics for solving the multi-robot coverage problem. The first solution presented is a direct extension of an efficient single robot area coverage algorithm, based on an exact cellular decomposition. The second algorithm is a greedy approach that divides the area into equal regions and applies an efficient single-robot coverage algorithm to each region. We present experimental results for two algorithms. Results indicate that our approaches provide good coverage distribution between robots and minimize the workload per robot, meanwhile ensuring complete coverage of the area.Comment: In proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 201

Synaptic activity is not required for establishing heterogeneity of inner hair cell ribbon synapses

Neural sound encoding in the mammalian cochlea faces the challenge of representing audible sound pressures that vary over six orders of magnitude. The cochlea meets this demand through the use of active micromechanics as well as the diversity and adaptation of afferent neurons and their synapses. Mechanisms underlying neural diversity likely include heterogeneous presynaptic input from inner hair cells (IHCs) to spiral ganglion neurons (SGNs) as well as differences in the molecular profile of SGNs and in their efferent control. Here, we tested whether glutamate release from IHCs, previously found to be critical for maintaining different molecular SGN profiles, is required for establishing heterogeneity of active zones (AZs) in IHCs. We analyzed structural and functional heterogeneity of IHC AZs in mouse mutants with disrupted glutamate release from IHCs due to lack of a vesicular glutamate transporter (Vglut3) or impaired exocytosis due to defective otoferlin. We found the variance of the voltage-dependence of presynaptic Ca2+ influx to be reduced in exocytosis-deficient IHCs of otoferlin mutants. Yet, the spatial gradients of maximal amplitude and voltage-dependence of Ca2+ influx along the pillar-modiolar IHC axis were maintained in both mutants. Further immunohistochemical analysis showed an intact spatial gradient of ribbon size in Vglut3–/– mice. These results indicate that IHC exocytosis and glutamate release are not strictly required for establishing the heterogeneity of IHC AZs