Notes on sufficient conditions for a graph to be Hamiltonian

The first part of this paper deals with an extension of Dirac's Theorem to directed graphs. It is related to a result often referred to as the Ghouila-Houri Theorem. Here we show that the requirement of being strongly connected in the hypothesis of the Ghouila-Houri Theorem is redundant. The Second part of the paper shows that a condition on the number of edges for a graph to be hamiltonian implies Ore's condition on the degrees of the vertices.

Network construction and graph theoretical analysis of functional language networks in pediatric epilepsy

This dissertation introduces a new approach for assessing the effects of pediatric epilepsy on the language connectome. Two novel data-driven network construction approaches are presented. These methods rely on connecting different brain regions using either extent or intensity of language related activations as identified by independent component analysis of fMRI data. An auditory description decision task (ADDT) paradigm was used to activate the language network for 29 patients and 30 controls recruited from three major pediatric hospitals. Empirical evaluations illustrated that pediatric epilepsy can cause, or is associated with, a network efficiency reduction. Patients showed a propensity to inefficiently employ the whole brain network to perform the ADDT language task; on the contrary, controls seemed to efficiently use smaller segregated network components to achieve the same task. To explain the causes of the decreased efficiency, graph theoretical analysis was carried out. The analysis revealed no substantial global network feature differences between the patient and control groups. It also showed that for both subject groups the language network exhibited small-world characteristics; however, the patient's extent of activation network showed a tendency towards more random networks. It was also shown that the intensity of activation network displayed ipsilateral hub reorganization on the local level. The left hemispheric hubs displayed greater centrality values for patients, whereas the right hemispheric hubs displayed greater centrality values for controls. This hub hemispheric disparity was not correlated with a right atypical language laterality found in six patients. Finally it was shown that a multi-level unsupervised clustering scheme based on self-organizing maps, a type of artificial neural network, and k-means was able to fairly and blindly separate the subjects into their respective patient or control groups. The clustering was initiated using the local nodal centrality measurements only. Compared to the extent of activation network, the intensity of activation network clustering demonstrated better precision. This outcome supports the assertion that the local centrality differences presented by the intensity of activation network can be associated with focal epilepsy.^

9th Conference on Cuban and Cuban-American Studies, Dispersed Peoples: The Cuban and Other Diasporas [Call for Papers and Panels]

This is the call for papers and panels for the 9th Conference on Cuban and Cuban-American Studies, Dispersed Peoples: The Cuban and Other Diasporas.

Intracranial Volume Estimation and Graph Theoretical Analysis of Brain Functional Connectivity Networks

Understanding pathways of neurological disorders requires extensive research on both functional and structural characteristics of the brain. This dissertation introduced two interrelated research endeavors, describing (1) a novel integrated approach for constructing functional connectivity networks (FCNs) of brain using non-invasive scalp EEG recordings; and (2) a decision aid for estimating intracranial volume (ICV). The approach in (1) was developed to study the alterations of networks in patients with pediatric epilepsy. Results demonstrated the existence of statistically significant (p

Factors Affecting the Adoption of New Technology: the case of 311 Government Call Centers

Government call centers (311) were first created to reduce the volume of non-emergency calls that were being placed to emergency 911 call centers. The number of 311 call centers increased from 57 in 2008 to about 300 in 2013. Considering that there are over 2,700 municipal government units across the United States, the adoption rate of the 311 centers is arguably low in the country. This dissertation is an examination of the adoption of 311 call centers by municipal governments. My focus is specifically on why municipal governments adopt 311 and identifying which barriers result in the non-adoption of 311 call centers. This dissertation is possibly the first study to examine the adoption of 311 call centers in the United States. The dissertation study has identified several significant factors in the adoption and non-adoption of 311 government call centers. The following factors were significant in the adoption of 311 government call centers: managerial support, financial constraints, organizational responsiveness, strategic plan placement, and technology champion. The following factors were significant barriers that resulted in the non-adoption of a 311 government call center; no demand from citizens, start up costs, annual operating costs, unavailability of funding, and no obvious need for one.If local government entities that do not have a 311 government call center decide to adopt one, this study will help them identify the conditions that need to be in place for successful adoption to occur. Local government officials would first need to address the barriers in setting up the 311 call centers.

Factors affecting the adoption of new technology: The case of 311 government call centers

Government call centers (311) were first created to reduce the volume of non-emergency calls that were being placed to emergency 911 call centers. The number of 311 call centers increased from 57 in 2008 to about 300 in 2013. Considering that there are over 2,700 municipal government units across the United States, the adoption rate of the 311 centers is arguably low in the country. This dissertation is an examination of the adoption of 311 call centers by municipal governments. My focus is specifically on why municipal governments adopt 311 and identifying which barriers result in the non-adoption of 311 call centers. This dissertation is possibly the first study to examine the adoption of 311 call centers in the United States. ^ The dissertation study has identified several significant factors in the adoption and non-adoption of 311 government call centers. The following factors were significant in the adoption of 311 government call centers: managerial support, financial constraints, organizational responsiveness, strategic plan placement, and technology champion. The following factors were significant barriers that resulted in the non-adoption of a 311 government call center; no demand from citizens, start up costs, annual operating costs, unavailability of funding, and no obvious need for one. ^ If local government entities that do not have a 311 government call center decide to adopt one, this study will help them identify the conditions that need to be in place for successful adoption to occur. Local government officials would first need to address the barriers in setting up the 311 call centers. ^

The Eliana Rivero Research Scholarship in Cuban Studies- Call for Applications from Graduate Students

This flyer promotes a call for applications from Graduate Students for the Eliana Rivero Research Scholarship in Cuban Studies. The scholarship provides one graduate student the opportunity to conduct research in Cuban studies- with special emphasis in the humanities- at the Cuban Research Institute. The deadline for applications is February 15, 2016.

Network Construction and Graph Theoretical Analysis of Functional Language Networks in Pediatric Epilepsy

This dissertation introduces a new approach for assessing the effects of pediatric epilepsy on the language connectome. Two novel data-driven network construction approaches are presented. These methods rely on connecting different brain regions using either extent or intensity of language related activations as identified by independent component analysis of fMRI data. An auditory description decision task (ADDT) paradigm was used to activate the language network for 29 patients and 30 controls recruited from three major pediatric hospitals. Empirical evaluations illustrated that pediatric epilepsy can cause, or is associated with, a network efficiency reduction. Patients showed a propensity to inefficiently employ the whole brain network to perform the ADDT language task; on the contrary, controls seemed to efficiently use smaller segregated network components to achieve the same task. To explain the causes of the decreased efficiency, graph theoretical analysis was carried out. The analysis revealed no substantial global network feature differences between the patient and control groups. It also showed that for both subject groups the language network exhibited small-world characteristics; however, the patient’s extent of activation network showed a tendency towards more random networks. It was also shown that the intensity of activation network displayed ipsilateral hub reorganization on the local level. The left hemispheric hubs displayed greater centrality values for patients, whereas the right hemispheric hubs displayed greater centrality values for controls. This hub hemispheric disparity was not correlated with a right atypical language laterality found in six patients. Finally it was shown that a multi-level unsupervised clustering scheme based on self-organizing maps, a type of artificial neural network, and k-means was able to fairly and blindly separate the subjects into their respective patient or control groups. The clustering was initiated using the local nodal centrality measurements only. Compared to the extent of activation network, the intensity of activation network clustering demonstrated better precision. This outcome supports the assertion that the local centrality differences presented by the intensity of activation network can be associated with focal epilepsy.