Individual neurons in the primary visual cortex respond selectively to different features of visual stimuli, such as spatial orientation or direction of motion. A longstanding goal in systems neuroscience has been to understand the transformations single cells perform as they integrate synaptic inputs to generate spiking output. Recent technological developments have facilitated these lines of investigation by enabling direct measurement of the functional properties of single synaptic inputs to neurons in the neocortex. It remains an outstanding question as to whether the tuning of single neocortical neurons can be predicted by their excitatory synaptic inputs. Here, I show that excitatory synaptic inputs exhibit significant functional diversity with respect to orientation and direction selectivity. I show that cells can use at least two strategies to overcome this functional diversity to achieve selective responses in the face of broadly tuned excitatory input: enhancing responses to the preferred stimuli and suppressing responses to the non-preferred stimuli. In the case of orientation selectivity, synaptic inputs cluster according to orientation preference and evoke local dendritic nonlinearities, thereby enhancing somatic responses to the preferred direction. For direction selectivity, cells receive excitatory synaptic inputs tuned to the preferred and null directions, but selectively suppress inputs tuned for the null direction to enhance direction selectivity. This suppression comes from direction-tuned GABAergic interneurons that make longrange, intercolumnar projections to enhance direction selectivity. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

In this thesis, I examine the structure of developmental or remedial English education at U. S. two-year community colleges, specifically focusing on the disparities between Florida’s English for Academic Purposes (EAP), an English as a Second Language (ESL) program, and Developmental English (Dev English), a Basic Writing program. Both programs supposedly prepare disadvantaged and/or immigrant students for freshman composition, but they employ very different pedagogies. Drawing on existing research and my own experience as a student and a teacher, I present English as it is employed to assimilate and empower second-language users, investigate the role of Florida’s institution in promoting EAP over Dev English, and discuss issues of identity and the categorization of students. I close by recommending the teaching of English as a Second Language – reading, writing, and basic language skills – to all developmental students, immigrant or native, to equip them for higher learning and a competitive workforce. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

The majority of HIV prevalence is found in Sub-Saharan Africa with 36.9 mil- lion living with HIV/AIDS. The cultural implications such as patient non-compliance or denial of available routine medical care can potentially cause limitations on the ef- fectiveness of detecting such virulent pathogens and manage chronic disease. The lack of access to healthcare and further socioeconomic impacts hinder the ability to ade- quately diagnose and treat infection in resource-limited settings. Intervention through diagnosis and treatment helps prevent the spread of transmission, where pre-exposure prophylaxis or active disease prevention measures are not readily available. The cur- rent gold standard for HIV detection is by molecular detection; Reverse-Transcription Polymerase Chain Reaction is widely used that employs cycles of temperature condi- tions that require a thermal cycling platform and typically laboratory space for RNA extraction separate from RT-PCR space required. Serological detection can be ad- vantageous for surveillance and screening, Lateral Flow Assays and Enzyme-Linked Immunosorbent Assay (ELISA) can detect a viral protein (antigen) or antibodies. The ELISA can require at least 12 hours of assay preparation and takes a diagnostic laboratory many resources to run. There is need to develop Point-of-Care (POC) testing that can potentially be used for decentralized testing that can leverage ex- isting technologies such as smart phone capability and routine medical or diagnostic tests with cutting edge applications leveraging micro uidics, nanotechnology and in- tegrated circuit design. Such technologies allow for automated, rapid turnaround and cost-e ective diagnosis of HIV, where these assays could potentially be read- ily deployed. It is such technology that can potentially change the way diagnostics are performed, as POC technology can be rapidly disseminated, enable decentralized testing and, is user-friendly. A novel smart phone-enabled automated magnetic bead- based platform was developed for a micro uidic ELISA for HIV-1 detection at the POC to meet this demand. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Page 296 blank. Includes bibliographical references.

The aim of this research is to study the formation mechanism of Barrier Layers (BL) in the western tropical Atlantic and their influence on the tropical Atlantic climate at both short and long timescales. Many Coupled General Circulation Models (CGCMs) tend to overestimate the salinity in the Atlantic warm pool or the Northwestern Tropical Atlantic (NWTA) and underestimate the surface salinity in the subtropical salinity maxima region. Most of these models also suffer from a seasurface temperature (SST) bias in the NWTA region, leading to suggestions that the upper ocean salinity stratification may need to be improved in order to improve the BL simulations and thus the SST through BL-SST-Intertropical Convergence Zone (ITCZ) feedbacks. We used a CGCM to perform a set of idealized numerical experiments to understand the sensitivity of the BL and consequently SST in the NWTA region to freshwater flux and hence the upper ocean salinity strati cation. We find that the BL of the western tropical Atlantic is quite sensitive to upper ocean salinity changes in the Amazon River discharge region and the subtropical salinity maxima region. The BL phenomenon is further manifested by the formation of winter temperature inversions in our model simulations. However, in the region of improved BL simulation, the SST response is not statistically significant. SST response to Tropical Cyclones (TCs) is studied for the Atlantic region using a high-resolution coupled regional climate model (CRCM) and observational data sets. The presence of a BL, defined as the layer below the mixed layer that separates the base of the isothermal layer from the base of the isohaline layer, is found to modulate the SST response. The amplitude of TC-induced surface cooling is reduced by more than 35 percent in the presence of a BL, as a consequence of the weak thermal stratification. Furthermore, in locations when the BL exhibits a temperature inversion, TC-induced mixing can result in weak surface warming. BLs considerably reduce the rightward bias for tropical storms, but the effect is less conspicuous for TCs. The enthalpy flux into the atmosphere at the air-sea interface is enhanced by 16 percent and the increase in upper ocean potential energy due to TC-induced mixing is reduced by 25 percent in the presence of BLs. The results from the coupled model are supported by an observational analysis performed using re-analysis data sets, as well as data from Argo floats and TRMM satellite. As previous modeling and observational studies have indicated that the surface cooling caused by TC-induced mixing acts as a negative feedback for its intensity, results from our study suggest that BLs may have potential implications for TC intensity prediction.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Bibliography: leaves 88-95.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references (leaves 125-138). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Georges Bank; Atlantic cod; environmental quality. Includes bibliographical references (p. 38-42).

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