4,770 research outputs found
Seglearn: A Python Package for Learning Sequences and Time Series
Seglearn is an open-source python package for machine learning time series or
sequences using a sliding window segmentation approach. The implementation
provides a flexible pipeline for tackling classification, regression, and
forecasting problems with multivariate sequence and contextual data. This
package is compatible with scikit-learn and is listed under scikit-learn
Related Projects. The package depends on numpy, scipy, and scikit-learn.
Seglearn is distributed under the BSD 3-Clause License. Documentation includes
a detailed API description, user guide, and examples. Unit tests provide a high
degree of code coverage
Microelectromechanical Optical Beam Steering Systems
The development of microelectromechanical systems (MEMS) has matured to the point where the fabrication of micron sized devices is feasible. State of the art MEMS construction processes now support the fabrication of novel optical devices that could not previously be built. This dissertation reports on the development of innovative micro optical devices such as Variable Blaze Gratings (VBGs) using state of the art MEMS construction processes. The principle application of the micro optical devices described in this dissertation is steering optical beams; however other applications such as spectral analysis are identified. Specific optical beam steering systems developed and characterized in this work include: optical phased arrays, VBGs, decentered microlens arrays, and integrated Vertical Cavity Surface Emitting Laser (VCSEL) micro mirror systems. Optical power induced damage to micro machined mirrors is also modeled and tested. In addition a number of new MEMS devices were created during this research including: double hot arm thermal actuators, optical hybrid devices such as variable blaze phased arrays and focusing micro mirrors, and non-linear flexures. Extensive Fourier analysis and optical testing of the micro optical devices was used to verify device operation
Requiring Unions to Notify Covered Employees of Their Rights to Be an Agency Fee Payer in the Post Beck Era
John H. Fanning Labor Law Writing Competition Winne
Post-Transcriptional Control of Human Cellular Senescence: A Dissertation
The central dogma of biology asserts that DNA is transcribed into RNA and RNA is translated into protein. However, this overtly simplistic assertion fails to portray the highly orchestrated and regulated mechanisms of transcription and translation. During the process of transcription, RNA provides the template for translation and protein synthesis as well as the structural and sequence specificity of many RNA and protein-based machines. While only 1-5% of the genome will escape the nucleus to be translated as mRNAs, complex, parallel, highly-conserved mechanisms have evolved to regulate specific mRNAs. Trans-acting factors bind cis-elements in both the 5 and 3 untranslated regions of mRNA to regulate their stability, localization, and translation. While a few salient examples have been elucidated over the last few decades, mRNA translation can be reversibly regulated by the shortening and lengthening of the 3 polyadenylate tail of mRNA. CPEB, an important factor that nucleates a complex of proteins to regulate the polyadenylate tail of mRNA, exemplifies a major paradigm of translational control during oocyte maturation and early development. CPEB function is also conserved in neurons and somatic foreskin fibroblasts where it plays an important role in protein synthesis dependent synaptic plasticity and senescence respectively. Focusing on the function of CPEB and its role in mRNA polyadenylation during human cellular senescence, the following dissertation documents the important finding that CPEB is required for the normal polyadenylation of p53 mRNA necessary for its normal translation and onset of senescence. Cells that lack CPEB have abnormal levels of mitochondria and ROS production, which are demonstrated to arise from the direct result of hypomorphic p53 levels. Finally, in an attempt to recapitulate the model of CPEB complex polyadenylation in human somatic cells, I unexpectedly find that Gld-2, a poly(A) polymerase required for CPEB-mediated polyadenylation in Xenopus laevis oocytes, is not required for p53 polyadenylation, but instead regulates the stability of a microRNA that in turn regulates CPEB mRNA translation. Furthermore, I demonstrate that CPEB requires Gld-4 for the normal polyadenylation and translation of p53 mRNA
Helical Engine
A new concept for in-space propulsion is proposed in which propellant is not ejected from the engine, but instead is captured to create a nearly infinite specific impulse. The engine accelerates ions confined in a closed loop to relativistic speeds, and slightly varies their velocity to change their momentum. The engine then moves the ions back and forth along the direction of travel to produce thrust. This in-space engine is intended to be used for long-term satellite station-keeping without refueling or to propel spacecraft across interstellar distances. The engine has no moving parts other than ions traveling in a closed-loop vacuum line, trapped inside electric and magnetic fields
A detailed study on understanding glycopolymer library and Con A interactions
Synthetic glycopolymers are important natural oligosaccharides mimics for many biological applications. To develop glycopolymeric drugs and therapeutic agents, factors that control the receptor-ligand interaction need to be investigated. A library of well-defined glycopolymers has been prepared by the combination of copper mediated living radical polymerization and CuAAC click reaction via post-functionalization of alkyne-containing precursor polymers with different sugar azides. Employing Concanavalin A as the model receptor, we explored the influence of the nature and densities of different sugars residues (mannose, galactose, and glucose) on the stoichiometry of the cluster, the rate of the cluster formation, the inhibitory potency of the glycopolymers, and the stability of the turbidity through quantitative precipitation assays, turbidimetry assays, inhibitory potency assays, and reversal aggregation assays. The diversities of binding properties contributed by different clustering parameters will make it possible to define the structures of the multivalent ligands and densities of binding epitopes tailor-made for specific functions in the lectin-ligand interaction. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2588–259
The Motivation of Students of Color for Pursuing Leadership Positions at Faith-Based Universities
As faith-based universities increasingly diversify the culture of their student body, student leadership roles also diversify. While there is literature on barriers and challenges students of color experience in these roles, there is little to help understand their motivation in pursuing these roles. Using conversations, interviews, and surveys this research was conducted to start such a conversation. The researchers\u27 goal was to go beyond conventional wisdom and begin gathering data reflecting the experiences of students of color on our campuses. While compensation is definitely a motivation, this research suggested there might be a variety of reasons to pursue these roles
Deletion of astroglial CXCL10 delays clinical onset but does not affect progressive axon loss in a murine autoimmune multiple sclerosis model.
Multiple sclerosis (MS) is characterized by central nervous system (CNS) inflammation, demyelination, and axonal degeneration. CXCL10 (IP-10), a chemokine for CXCR3+ T cells, is known to regulate T cell differentiation and migration in the periphery, but effects of CXCL10 produced endogenously in the CNS on immune cell trafficking are unknown. We created floxed cxcl10 mice and crossed them with mice carrying an astrocyte-specific Cre transgene (mGFAPcre) to ablate astroglial CXCL10 synthesis. These mice, and littermate controls, were immunized with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG peptide) to induce experimental autoimmune encephalomyelitis (EAE). In comparison to the control mice, spinal cord CXCL10 mRNA and protein were sharply diminished in the mGFAPcre/CXCL10fl/fl EAE mice, confirming that astroglia are chiefly responsible for EAE-induced CNS CXCL10 synthesis. Astroglial CXCL10 deletion did not significantly alter the overall composition of CD4+ lymphocytes and CD11b+ cells in the acutely inflamed CNS, but did diminish accumulation of CD4+ lymphocytes in the spinal cord perivascular spaces. Furthermore, IBA1+ microglia/macrophage accumulation within the lesions was not affected by CXCL10 deletion. Clinical deficits were milder and acute demyelination was substantially reduced in the astroglial CXCL10-deleted EAE mice, but long-term axon loss was equally severe in the two groups. We concluded that astroglial CXCL10 enhances spinal cord perivascular CD4+ lymphocyte accumulation and acute spinal cord demyelination in MOG peptide EAE, but does not play an important role in progressive axon loss in this MS model
- …