THE OGONI OF SOUTHEASTERN NIGERIA AN ANALYSIS OF ART AND IDENTITY (AFRICA, IKPONG, O U OLU, AMANIKPO SOCIETY)

COBB, SARAH TRAVIS Columbia University 1995 국내박사

Control and connection : themes in the plays of Edward Albee

Cobb, Mary Elizabeth U. M. I. 1984 국내박사

Coral records of the el nino-southern oscillation and tropical pacific climate over the last millennium

Cobb, Kim M. UMI 2002 국내박사

Dynamic simulations of suspensions of rod-like polymers and colloids

Cobb, Philip D University of Florida 2006 해외박사(DDOD)

Simulations presented in this dissertation advance knowledge of the dynamics of suspensions of rigid and semi-rigid Brownian fibers. This work resolves competing claims concerning the power-law scaling for the concentration dependence of the rotational diffusivities. The power-law scaling states that the rotational diffusivity DR scales as DR/ DR0 ∼ (nL3)nu, where DR0 is the rotational diffusivity of a single fiber in infinite dilution, n is the number density (number of fibers per unit volume), and L is the fiber length. The choice of hydrodynamic model, with an intrinsic ratio of the rotational to translational diffusivities at infinite dilution L2DR0/DT0 , sets the value of the exponent nu in the scaling. The aspect ratio of the fibers also affects the scalings, with strong variations for ratios less than fifty; ratios of fifty or higher can considered infinitely thin. An analysis of the numerical integration method was performed, resulting in a new algorithm with less error and higher efficiency. Adding flexibility delays the number density at which fibers become significantly hindered by their neighbors and enter the regime where a strong decrease in the rotational diffusivity occurs. Once within this semi-dilute regime, the power-law scalings of the semi-rigid fibers closely match those of rigid fibers with corresponding hydrodynamic models and aspect ratios. Comparing simulations of rigid and semi-rigid fibers to experimental results demonstrates that different micro-mechanical models can produce results which are indistinguishable within measurement capabilities. Consequently, proper models cannot be distinguished based solely on their rotational diffusivities, so other measures are needed to identify the appropriate model. Including hydrodynamic interactions into the simulations will provide further insights into the dynamics of fiber suspensions. Investigations of a parallel computation of the pair interactions and Cholesky decomposition indicate that simulating systems of over one hundred fibers is feasible.

A state estimation framework for ultrasonic structural health monitoring of fastener hole fatigue cracks

Cobb, Adam Georgia Institute of Technology 2008 해외박사(DDOD)

The development of structural monitoring systems is a critical research area because of the age and sustainment costs associated with many aircraft in use today. Specifically, integrated structural health monitoring (SAM) systems are advantageous because they allow for automated, near real-time assessment of the state of the structure, where the automation improves both the accuracy of the measurements and allows for more frequent system interrogation than possible with traditional nondestructive evaluation methods. Ultrasonic techniques are particularly well-suited for SHM systems because of their potential to detect and track damage well before structural failure using in situ sensors. The research problem considered in this thesis is detection and tracking of fatigue cracks emanating from fastener holes in metallic structural components. The sensing method utilizes attached ultrasonic transducers, and tracking of damage is achieved by employing a state estimation framework that incorporates a well-known empirical model for crack growth and a measurement model relating the ultrasonic response to crack size. The state estimation process is preceded by an automated crack detection algorithm, and can be followed by a prediction of remaining life assuming future usage. The state estimation framework provides a better estimate of crack size than either the ultrasonic measurement model or crack growth model alone. Although the example application is monitoring of fastener holes, the general approach is applicable to a variety of SHM problems.

Water relations of rattans

Cobb, Alexander Ruggles Harvard University 2006 해외박사(DDOD)

Rattans have the longest aerial stems of any plant, yet lack secondary growth. As vines, they must convey water to a large area of leaves through a narrow stem. The unusual vascular structure of rattans relative to other palms suggests adaptation to these hydraulic demands. But unlike most other vines, which are optimized for transport, rattans have a modified vascular model that would seem to increase their hydraulic resistance. Their large axial vessels are interconnected only by small transverse vessels. In addition, water is forced to flow through a layer of living parenchyma to reach the leaves. The work presented here examined the consequences of rattans' vascular model for the efficiency and safety of water transport in their stems, based on experiments in Malaysia and Australia on Calamus caesius, Daemonorops sparsiflora, and Calamus caryotoides. Single-vessel and whole stem measurements in the rattan Daemonorops sparsiflora showed that the small transverse vessels separating axial vessels increase the contribution of resistance between vessels in the rattan stem compared to this resistance in most other plants. However, all three study species had sufficiently wide vessels that their stems' area-normalized conductances were as high as those of other tropical vines. The parenchyma layer separating leaf and stem xylem contributed little to the resistance between stem and leaves. Water potential measurements showed that a smaller proportion of the hydraulic resistance between soil and atmosphere occurred in the crown of the rattan Calamus caryotoides than previously measured in the palm Rhapis excelsa. The large area of overlap between metaxylem and protoxylem in the leaf trace may allow a low resistance in spite of the high resistivity of the parenchyma barrier. Because rattans have no vascular cambium, their vascular system must be robust against cavitation, spontaneous vaporization of water in the xylem. I explored whether the rattan vascular system remains functional by successfully avoiding cavitation or through some mechanism removing gas bubbles, or emboli, caused by cavitation. Patterns in stem embolism in Calamus caryotoides in Queensland suggested that rattans may be unable to reverse embolism in their stems.

"Who can I run to?" Stereotypes, attributions of culpability and help-giving to battered African American women

Cobb, Maisha Jamila University of California, Los Angeles 2001 해외박사(DDOD)

Family violence remains the cause of a significant number of injuries and homicides in America. Despite growing incidences involving black families, a paucity of research exists regarding beliefs and responses to black victims of abuse. The purpose of the present research was to apply attribution theory to an investigation of reactions to victims of domestic violence and determine potential effects of race on help giving to abuse victims. The theoretical framework states that causal beliefs give rise to inferences about personal responsibility, which in turn generate emotions, which then guide behavioral responses. The cognitive-affective-behavioral model was used to test assumptions that stereotypes about victims based on race would impact culpability inferences, elicit negative emotions and result in decreased helping behavior toward black victims. Three studies were conducted: Study 1 investigated the stereotypes held by 88 college students about battered women, black women and white women; Study 2 examined the cognitive and affective judgments of 150 college students concerning battered women's victimization and explored how these attributions influenced helping behaviors offered to black and white abuse victims; and Study 3 explored the attributional processes of 71 female social service providers who work with battered women, to determine how their attributions and intent to help black and white victims mirrored or differed from those of lay respondents. Findings revealed the use of negative stereotypes to depict black women, as well as higher culpability inferences and negative emotion directed at black abuse victims. The results are discussed in terms of their significance to attribution theory, stereotyping and the delivery of domestic violence services.

Marriage and family therapists' endorsement of couples treatment for intimate partner violence

Cobb, Rebecca Ann The Florida State University 2014 해외박사(DDOD)

A six-group randomized experimental study was used to investigate the factors that are associated with a marriage and family therapist's decision to work with clients individually or as a couple when they present with intimate partner violence (IPV). Investigated factors included the type of IPV experienced by the clients, the therapist's accuracy in identifying the type of violence experienced by clients, and the therapist's experience with IPV in their own romantic relationships, as moderated by levels of differentiation. Participants included 275 members of the American Association for Marriage and Family Therapy. A chi square test revealed that participants who received vignettes portraying situational couple violence were more likely to endorse couples treatment as the preferred treatment modality than participants who received vignettes portraying intimate terrorism. Additional chi square tests revealed that among participants who received vignettes portraying situational couple violence, those who were accurately able to identify the type of violence portrayed in the vignette were more likely to endorse couples treatment as the preferred treatment modality than those who did not accurately identify the type of violence. Additional analyses, however, suggest that accurate identification and appropriate treatment choice may be more difficult in situations in which intimate terrorism is taking place, especially when women are the perpetrators of this abuse. Logistic regression indicated that there was not a significant relationship between therapists' personal experience with IPV and endorsement of treatment type. In addition, differentiation did not moderate the relationship between IPV experienced in participants' own romantic relationships and their endorsement of couples treatment. The current study indicates that marriage and family therapists are likely to make IPV treatment choices primarily based on the type of violence experienced by the couple. It appears that IPV treatment choice is not influenced by personal experience with IPV, but rather by the therapist's accurate identification of IPV type and the gender of the perpetrator of abuse. These findings ultimately highlight the need continued education on IPV, IPV types, gender biases with regards to IPV, and the importance of taking safety into consideration when making treatment decisions.

The kinematic effects of custom molded orthotics on the stance phase of gait using a multi-segment foot model

Cobb, Stephen C Georgia State University 2005 해외박사(DDOD)

The effect of foot structure and custom molded functional orthotic (FO) intervention on walking kinematics was investigated using a novel multi-segment three-dimensional (3D) foot model. Eighteen participants with low and mobile arch structures (LAMF) and 11 participants with "typical" arch structure and mobility (TYPF) were recruited. The LAMF participants were randomly assigned to one of two different FOs. Following a semi-weightbearing anatomical calibration procedure, subjects completed 5 walking trials along a 10 m walkway at a speed of 3--3.15 mph. Three-dimensional data were captured using 8 optical electronic cameras sampling at 120 Hz (Peak Performance Technologies, Inc.). The LAMF group performed trials during no FO and FO conditions while the TYPF group only performed no FO condition trials. A software program written in Matlab (MathWorks) was used to compute joint angles and discrete kinematic stance phase variables. The LAMF group (no FO condition) demonstrated less rearfoot complex (RC) sagittal plane angular displacement (p = 0.012), slower time-to-peak (TTP) inversion (p = 0.043) and greater inversion velocity (p = 0.049) compared to the TYPF group. LAMF group no FO versus FO condition comparisons revealed increased RC inversion (p = 0.001) and internal rotation (p = 0.016) angles and decreased eversion (p = 0.001) angles during the FO condition. At the calcaneonavicular complex, later TTP plantarflexion angle (p = 0.001) and eversion velocity (p = 0.045) and earlier adduction angular velocity (p = 0.012) were observed during the FO condition. At the medial forefoot, decreased plantarflexion (p = 0.002) and inversion (p = 0.001) angles and sagittal plane angular displacements (p < 0.001) were observed during the FO condition while eversion angles were increased (p = 0.012). Decreased plantarflexion (p = 0.004) and eversion (p = 0.003) velocities were also observed during the FO condition. Finally, decreased eversion angles (p = 0.046) and sagittal (p = 0.008) and frontal plane (p = 0.001) angular displacements were observed at the first metatarsophalangeal joint during the FO condition. The results of the study suggest significant kinematic differences do exist between subjects with "typical" foot structures and those with low and mobile arch structures. It also demonstrated that FO intervention significantly affects walking gait kinematics in persons with low and mobile arch structures.

Sisterly love and sibling rivalry: The poetic response to painting in Spain's Golden Age

Cobb, Erica McClellan The University of North Carolina at Chapel Hill 2005 해외박사(DDOD)

Poetry and painting have long been described as sister arts. Since Antiquity the belief that these two arts share a closer connection than all other arts has remained steadfast. The number of treatises on the subject is vast and varied, yet few studies have focused specifically on the relationship between painting and poetry of the Spanish Golden Age. This dissertation explores the interaction between the sister arts in Spain at that time, which produced a large corpus of poetry dedicated specifically to painting. My study analyzes poetry written in response to both narrative painting and portraiture in the Spanish Golden Age. In the first Chapter, I examine the cultural climate that allowed and encouraged the sharing of ideas between poet and painter. I also address the paragone, or rivalry between the arts, as interactions between painting and poetry were not always of a positive nature, but were critical and denunciatory. Thus poetry that reflects upon art allows the modern reader to understand how it was perceived during the Golden Age, informs about which artists were lauded and admired, as well as which artists were censured, and why. In addition, various poems allude to the close friendships between poet and painter. Subsequent chapters analyze those poems composed in response to specific paintings. Such poems reveal which art works were familiar to the poet, which drew the poet's attention, and which artists the poet admired or scorned. Contemplation of the images on the part of the poets tends to produce wither satisfaction or disgust. This dissertation sheds light on a long-neglected body of work, which represents the poet's views on art and artists. Each poem, though initially a response to a specific painting, expands to express related concerns, be they political, religious, or personal in nature. By concentrating on these individual poems and the works of art to which they respond, we learn not only of the poet's own artistic sensibilities, but of the importance art played in the culture of Golden Age Spain as a whole and how poetry gave voice to a certain segment of that society.