1,171 research outputs found
Characterization of Atmospheric Pressure Matrix Assisted Laser Desorption Ionization and Electrospray Ionization for a differential mobility spectrometer
No full textThesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (leaves 114-116).The following thesis entails the construction, testing, modification, and analysis of two systems that couple sample ion introduction methods with a Differential Mobility Spectrometer (DMS). The sample ionization methods used with a custom designed interface for the DMS were Electrospray Ionization (ESI) and Atmospheric Pressure Matrix Assisted Laser Desorption Ionization (AP-MALDI). In addition to system development, Fourier transform and decision tree analyses were explored as alternatives to lead-cluster mapping and genetic algorithms for analyzing and classifying data produced by the systems for large biomolecules. Findings from testing and experiments using the prototype system have led to a second generation design of the interface. Results from data analysis have also provided new insights into different methods for classifying data whose form changes drastically for different sample introduction methods.by Priya Agrawal.M.Eng.and S.B
Stratified external mixing at moderate Richardson number
No full textStratified turbulent mixing remains an unsolved problem. Turbulent mixing is complicated by its intermittent nature, its highly vortical motion and the large range of scales of its coherent structures. In order to help reduce the problem to a more tractable form, we consider vortex rings as a reproducible, idealized form of a turbulent coherent structure of a defined length and velocity scale. We generate vortex rings in a stably stratified two-layer fluid of varying Richardson number and observe the vortex ring induced mixing. While previous work has looked at the effect of individual vortex rings on the stratified interface, we analyze the aggregate mixing induced over many vortex ring generations. Over successive vortex rings collisions, the mixing rate converges to a constant for a range of Richardson numbers
Policy Analysis of Special Immigrant Juvenile Status S.B. 873
Full text linkThe purpose of this paper was to conduct a policy analysis on California's S.B. 873 which was enacted in 2014 and focuses on unaccompanied immigrant minors. This population was narrowed to those entering the U.S. from Central American countries Guatemala, Honduras, and El Salvador. This analysis used an Intersectionality-Based Policy Analysis (IBPA) Framework. The results demonstrated that this population has multi-layered needs when going through immigration proceedings to which there are many barriers to being successful in achieving U.S. residency. Some of these barriers include, language barriers and lack of legal representation, economic hardships based on the lack of benefits available to them, and lack of trauma focused care. S.B. 873 challenges and provides money for legal representation to become more available, expands benefits that this population can qualify for, and provides a path to appoint guardianship. This policy analysis explored the gaps in S.B. 873 through an Intersectionality-Based Policy Framework. Through this analysis, the author offers recommendations for future care of unaccompanied minors as they deal with the immigration system.by Carolina Cardoz
Author Correction: New perspectives on Neanderthal dispersal and turnover from Stajnia Cave (Poland)
Full text linkThe Author contributions section now reads:“W.N., A.N. and S.T. designed research; A.P., M.H., W.N., S.B., M.U., A.M., H.F., M.D.B., P.S., K.S., M.Ż., A.W., A.N. and S.T. performed research; A.P., M.H., W.N., S.B., M.U., A.M., H.F., M.D.B., P.S., K.S., M.Ż., A.W., A.N. and S.T. analysed data; A.P., M.H., S.T., W.N. and S.B. wrote the paper with the collaboration of all the co-authors.
Author Correction:A 41,500 year-old decorated ivory pendant from Stajnia Cave (Poland)
No full textCorrection to: Scientific Reports https://doi.org/10.1038/s41598-021-01221-6, published online 25 November 2021The original version of this Article contained errors in the author list where Marjolein D. Bosch was omitted from the author list, and Mikołaj Urbanowski was incorrectly listed as an author of the original Article, and has subsequently been removed.The Author contributions section now reads:“S.T. W.N. and A.N. conceived the project; S.T., W.N., A.P., M.B., S.C., M.D., H.F., A.M., M.D. B., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H., performed research; S.T., A.P., W.N., M.B., M.D.B., S.C., M.D., H.F., A.M., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H. analysed all archaeological data; S.T. and A.P. wrote the paper with the collaboration of all the co-authors.”The original Article and its accompanying Supplementary Information file have been corrected
Pisma Krzysztofa Kluka jako źródło leksykalne do Słownika języka polskiego S.B. Lindego
No full textThe aim of this paper is to discuss the writings by Krzysztof Kluk (1739–1796), a naturalist of the Enlightenment, the author of Dykcjonarz roślinny (Dictionary of plants) and guidebooks in the fi elds of botany, zoology, and mineralogy as lexical sources of Słownik języka polskiego (Dictionary of Polish) by S.B. Linde (LD). The paper presents an analysis of the material excerpted from Volumes 1 and 3 of LD, which has allowed the estimation that K. Kluk is discussed more frequently in the dictionary than J. Kochanowski, P. Kochanowski, J. Przybylski, and only slightly less frequently than M. Rej and W. Potocki. The material has been analysed also with the use of the method of semantic fields, which has enabled identification of the thematic circles that allow the determination of the angle from which S.B. Linde excerpted vocabulary from K. Kluk’s writings. The lexis from Kluk’s works in LD is not limited only to names of plants, animals or minerals; it covers also parts of the body, animal husbandry (e.g. horses, birds, bee-keeping, fishery), gardening, agriculture, animal diseases, metal and mineral working, transport, construction, home appliances, food, clothes, and social life
Voice Compression and Communications: Principles and Applications for Fixes and Wireless Channels
No full textUp-to-date, expert coverage of topics in wireless voice communications Voice communication is the most important facet of mobile radio service. Even when the predicted surge of wireless data and Internet services becomes a reality, voice will remain the most natural means of human communication. Voice Compression and Communications details issues in wireless voice communications and treats compression, channel coding, and wireless transmission as a joint subject. Part I covers background material, whereas Part II provides detailed information on both proprietary and standardized analysis-by-synthesis codecs, including the speech codecs of virtually all existing wireline-based and wireless systems. Parts III and IV discuss mainly research-based wideband, audio, as well as very low-rate schemes likely to find their way into future standards. Voice Compression and Communications describes fundamental concepts in a non-mathematical way early in the book for those with only a background knowledge of signal processing and communications. More advanced readers will find detailed discussions of theoretical principles, future concepts, and solutions to various specific wireless voice communications problems
Controls on shallow-marine stratigraphy; a process-response approach
No full textThis thesis is concerned with the interface between land and sea. The interaction of coastal evolution and the sedimentary record, in this case of a wave-dominated coastal system, over geological timescales (< 105 y) is investigated in relation to their forcing parameters such as relative sea-level change, sediment supply, and wave climate. The preserved sediments record the dynamics of the coastal system in stacked but uncomplete sediment packages, which formed as the coastline migrated in landward or seaward direction resulting from erosion and deposition of sand and clay along the shallow parts of the coastal system (< 100 m waterdepth). If we want to understand coastal evolution over geological timescales, we must be able to read or interpret the stratigraphic record. Reconstructing coastal evolution from preserved shallow-marine stratigraphy is very difficult. The sediment record is not complete due to phases of erosion and we know little about past local changes in relative sea level, sediment supply, and wave climate. Also, the individual effects of these variables on coastal evolution and the stratigraphic record are poorly known. As the processes that drive coastal evolution, and therefore the resulting sedimentary record, act over thousands of years it is not possible to simply take measurements and make observations. Nevertheless, the stratigraphic record is the key to understand coastal evolution over geological timecales because it is the only physical evidence. Therefore a two dimensional numerical model has been developed which simulates the processes which are presumably important for coastal evolution and the formation of the stratigraphic record over long timescales. This model, its development and some applications are described in this thesis with the goal of increasing our understanding of coastal dynamics over geological timescales.Civil Engineering and Geoscience
Rapid Caspian Sea-level change and its impact on Iranian coasts
No full textThe Late Pleistocene and Holocene evolution as well as recent developments of the southern coast of the Caspian Sea have been studied using remote sensing and core data. This thesis focuses firstly on recent shoreline shifts during the last rapid sea-level cycle between 1929 and 1995, with an amplitude of three meters. Secondly, it shows a reconstruction of past Caspian Sea-level change and palaeoenvironments in an area very sensitive to such changes. A new tentative Holocene Caspian Sea-level curve has been reconstructed, which might help to predict future Caspian Sea-level. Up to now there has been no consensus on the chronology and amplitudes of Holocene Caspian sea-level oscillations due to problems with sampling strategies, absolute dating, relative tectonics, deformation, different datum levels and absence of data on long-term development of Caspian Sea-level.Geoscience & EngineeringCivil Engineering and Geoscience
The impact of changes in sediment supply and sea-level on fluvio-deltaic stratigraphy
No full textStudies in stratigraphy are often driven by the predicted climate change and possible gains for the oil and gas industry. Because, at present predictions of the development of future deltaic architecture are insufficient. This thesis addresses the problem of qualitative and quantitative understanding of sedimentary systems in two stages. In the first stage the stratigraphy of Holocene delta deposits of the Kura and Mahakam deltas (respectively in Azerbaijan en Indonesia) are studied. Results from these studies provide insights as an analogue to ancient systems and serve as an example for expected future conditions. The results form the Kura delta show a prominent role for the rapid sea-level change of the Caspian Sea, while the results of Mahakam delta suggest an important role for the eustatic Holocene sea-level curve and the absence of floods of the Mahakam River. Information obtained from studies in a similar context have the potential to reduce uncertainties and increase confidence in models. The second stage of this thesis covers the development of a process-response simulation model to assess the impact of changes in sediment supply and sea-level on fluvio-deltaic stratigraphy. Anticipating on the dominant role of sediment supply on fluvial dominated deltas, a choice is made for a detailed investigation in how to incorporate good estimates of sediment supply in the numerical model, that enable to explore the possibilities of using a probabilistic approach instead of a deterministic output or geostatistical analysis.Civil Engineering and Geoscience
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