1,427 research outputs found
Probing Active to Sterile Neutrino Oscillations in the LENS Detector
Sterile neutrino conversion in meter scale baselines can be sensitively
probed using monoenergetic, sub-MeV, flavor pure e-neutrinos from an artificial
MCi source and the unique technology of LENS designed to oberve the low energy
solar neutrino spectrum via tagged CC e-neutrino capture in 115-In.
Active-sterile oscillations can be directly observed in the granular LENS
detector itself to critically test and extend resuls of short baseline
accelerator and reactor experiments.Comment: 4pages, 4 figures, text and figure change
\u3ci\u3eNon Magis Sed Melior,\u3c/i\u3e âNot More, but Betterâ
As part of the National Collegiate Honors Councilâs (2022) collection of essays about the value of honors to its graduates (1967â2019), the author reflects on the personal and professional impacts of the honors experience.
The year was 1989. I had moved from a rural community in Michigan to South Carolina to attend Columbia College, a private, liberal-arts womenâs college. The culture shock and adjustment were equal parts exhilarating and unnerving. I was welcomed by the warm, Southern charm of campus and was nurtured, personally and academically, by the close-knit community of the honors program. I had a rich college experience in general, but being an honors student changed the entire trajectory of my career and shaped me personally, instilling confidence, motivation, and purpose. The indelible mark stemmed from the programâs motto: Non Magis Sed Melior, âNot More, but Better.â The program was intentionally grounded not in the quantity of coursework but in the quality, delivering a deep academic experience that challenged students to reach their highest potential as scholars and leaders
Book Review: Total Care Management: A Physician Executive\u27s Guide to Medical Management for the 21st Century by Raymond J. Fabius, MD, CPE, FACPE
No abstract available
Study of diversity and function of the marine key group Vis6 with cultivation-independent methods
Phytoplankton in the ocean represents about 0.2% of all photosynthetic biomass on Earth, but is responsible for half of the global CO2 fixation. A large proportion of this produced organic matter is funneled through the microbial loop towards higher trophic levels by heterotrophic microorganisms. These have consequently a great impact on the global carbon cycle, the CO2 concentration in the atmosphere and ultimately our climate. Phytoplankton blooms are short-termed increases in phytoplankton biomass, followed by secondary blooms of heterotrophic bacteria. Taxonomic and ecological studies at the long term ecological research station Helgoland Roads, North Sea, revealed recurring patterns of bacteria on taxonomic and functional level. Members of the phylum Bacteroidetes and in particular of the class Flavobacteriia are among the major responders to phytoplankton blooms. Analyses with both cultivation and cultivation-independent techniques, based on genome sequencing and gene annotations, can reveal the role of individual groups in the degradation of phytoplankton derived organic matter. The focus of this work was the development of a culture-independent pipeline for the targeted access and the subsequent functional genome characterization of bacterial species from the environment. This pipeline combines fluorescence in situ hybridization (FISH) with fluorescence activated cell sorting (FACS) and subsequent genome sequencing. A taxon-specific FISH probe hybridizes to the target cells which are subsequently enriched by cell sorting based on the fluorescence signal. Finally, the DNA of the sorted cells is amplified and sequenced. The development of the pipeline involved an optimization of the recently developed hybridization chain reaction (HCR)-FISH method and the assessment of various cell fixatives concerning their influence on HCR-FISH signal intensity and the quality of genome sequencing and assembly. The developed pipeline was successfully applied on a planktonic seawater sample targeting the so far uncharacterized clade Vis6. This member of the Cryomorphaceae within the Flavobacteriia is recurring during spring phytoplankton blooms off the coast of Helgoland. The description of Vis6 as a novel candidate genus Candidatus Abditibacter with three species was enabled by the combination of the sequences retrieved from targeted sorting pipeline with additional data of North Sea metagenomes and abundance data based on the 16S rRNA identity of Vis6. The growth of Candidatus Abditibacter spp. is likely based on the utilization of phytoplankton-derived polysaccharides and proteins. In the future, the developed pipeline has the potential to be used on low abundance species from highly complex samples, where previous attempts with metagenomics have been unsuccessful so far
Haploinsufficiency of the Myc regulator Mtbp extends survival and delays tumor development in aging mice.
Alterations of specific genes can modulate aging. Myc, a transcription factor that regulates the expression of many genes involved in critical cellular functions was shown to have a role in controlling longevity. Decreased expression of Myc inhibited many of the deleterious effects of aging and increased lifespan in mice. Without altering Myc expression, reduced levels of Mtbp, a recently identified regulator of Myc, limit Myc transcriptional activity and proliferation, while increased levels promote Myc-mediated effects. To determine the contribution of Mtbp to the effects of Myc on aging, we studied a large cohort of Mtbp heterozygous mice and littermate matched wild-type controls. Mtbp haploinsufficiency significantly increased longevity and maximal survival in mice. Reduced levels of Mtbp did not alter locomotor activity, litter size, or body size, but Mtbp heterozygous mice did exhibit elevated markers of metabolism, particularly in the liver. Mtbp(+/-) mice also had a significant delay in spontaneous cancer development, which was most prominent in the hematopoietic system, and an altered tumor spectrum compared to Mtbp(+/+) mice. Therefore, the data suggest Mtbp is a regulator of longevity in mice that mimics some, but not all, of the properties of Myc in aging
Design and Analysis of a Reusable N2O-Cooled Aerospike Nozzle for Labscale Hybrid Rocket Motor Testing
A reusable oxidizer-cooled annular aerospike nozzle was designed for testing on a labscale PMMA-N20[1] hybrid rocket motor at Cal Poly-SLO.[2] The detailed design was based on the results of previous research involving cold-flow testing of annular aerospike nozzles and hot-flow testing of oxidizer-cooled converging-diverging nozzles. In the design, nitrous oxide is routed to the aerospike through a tube that runs up the middle of the combustion chamber. The solid fuel is arranged in an annular configuration, with a solid cylinder of fuel in the center of the combustion chamber and a hollow cylinder of fuel lining the circumference of the combustion chamber. The center fuel grain insulates the coolant from the heat of the combustion chamber. The two-phase mixture of nitrous oxide then is routed through channels that cool the copper surface of the aerospike. The outer copper shell is brazed to a stainless steel core that provides structural rigidity. The gaseous N2O flows from the end of aerospike to provide base bleed, compensating for the necessary truncation of the spike. Sequential and fully-coupled thermal-mechanical finite element models developed in Abaqus CAE were used to analyze the design of the cooled aerospike. The stress and temperature distributions in the aerospike were predicted for a 10-sec burn time of the hybrid rocket motor.
[1] PMMA stands for polymethyl methacrylate, a thermoplastic commonly known by the brand name PlexiglasÂź. N2O is the molecular formula for nitrous oxide.
[2] California Polytechnic State University, San Luis Obisp
An Experimental Investigation of the Effect on Interest of Reading Childrenâs Literature to Sixth Grade Students in Aberdeen, Washington
To determine the effect of a teacher\u27s reading literature upon the interest in reading books among sixth grade students, one group (experimental) participated in a twenty-eight week program of scheduled daily time during which they listened to literature read by their teacher. A second group (control) were not exposed to literature in this manner but otherwise participated in a similar school program
Anisotropic galaxy clustering measurements in Fourier space and cosmological implications from the BOSS DR12 sample
Moderne Rotverschiebungs-Galaxiendurchmusterungen können mittels Mehrfach-Faser-Spektroskopie groĂe Bereiche des Himmels abdecken. Dank der immer gröĂer werdenden DatensĂ€tze hat sich die Analyse der groĂskaligen Galaxienverteilung im Universum zu einer unschĂ€tzbaren Wissensquelle fĂŒr die Kosmologie entwickelt. Zusammen mit den Beobachtungen des kosmischen Mikrowellenhintergrunds (MWH) und Entfernungsbestimmungen anhand von groĂen Typ-Ia-Supernova-DatensĂ€tzen (SN) bilden die Galaxiendurchmusterungen ausschlaggebende Indikatoren fĂŒr die Korrektheit der Paradigmen des kosmologischen Weltbilds, des ÎCDM-Modells. Die Auswertung der Galaxienverteilung erlaubt mit Hilfe des Standardlineals, das durch die Baryonisch-akustischen Oszillationen gegeben ist, Entfernungsmessungen von ungesehener PrĂ€zision. Dies gewĂ€hrt Einblick in die zugrundeliegende physikalische Natur der Dunklen Energie (DE), welche fĂŒr die Beschleunigung der Ausdehung unseres Universums verantwortlich gemacht wird, indem die zeitliche Entwicklung der DE-Zustandsgleichung einge-
schrÀnkt werden kann. Zudem kann aus dem Signal der Verzerrungen im Rotverschiebungsraum die Wachstumsrate von kosmologischer Struktur bestimmt werden. Dies stellt einen Test der RelativitÀtstheorie dar, weil mögliche erweiterte Gravitationstheorien abweichende Wachstumsraten vorhersagen können.
Die abgeschlossenen Rotverschiebungsmessungen des âBaryon Acoustic Oscillation Surveyâ-Programms (kurz BOSS) brachten einen Galaxienkatalog hervor, der ein bisher unerreichtes Volumen abdeckt. In dieser Dissertation wird die kosmologische Information, die im rĂ€umlichen Leistungsdichtespektrum (LDS) der Rotverschiebungsraum-Galaxienverteilung des BOSS-Katalogs enthalten ist, genutzt, um den Parameterraum des ÎCDM-Modells und der wichtigsten möglichen Erweiterungen einzuschrĂ€nken. Vorherige Analysen des anisotropen Galaxien-LDS waren auf die Messung der Multipolzerlegung beschrĂ€nkt. FĂŒr die hier prĂ€sentierte Analyse wurde das Konzept der sogenannten âClustering Wedgesâ auf den Fourierraum ĂŒbertragen, um einen komplementĂ€ren Ansatz zur Vermessung des anisotropen LDS zu verfolgen. Dazu wird der varianzoptimierte SchĂ€tzer fĂŒr LDS-Wedges definiert und an die Galaxiengewichtung, die unvermeidbare Beobachtungsfehler im BOSS-Katalog behebt, angepasst. Zudem wird auch der Formalismus zur Beschreibung der Fensterfunktion auf die Wedges erweitert.
Das verwendete Modell fĂŒr das anistrope Galaxien-LDS ist auf neuartigen AnsĂ€tzen zur Modellierung der nichtlinearen Gravitationsdynamik und der Verzerrungen im Rotverschiebungsraum aufgebaut, welche die Genauigkeit der Modellvorhersagen speziell im Ăbergang in den nichtlinearen Bereich signifikant verbessern. Daher kann das LDS bis zu kleineren Skalen als in vorherigen Analysen ausgewertet werden, wodurch engere EinschrĂ€nkungen des kosmologischen Parameterraums erreicht werden. Die Modellierung wurde mit Hilfe von synthetischen Katalogen, die auf groĂvolumigen Mehrkörpersimulationen basieren, verifiziert. Dazu ist eine theoretische Vorhersage der Kovarianzmatrix der anisotropischen Vermessung der Galaxienverteilung nötig, wofĂŒr ein GauĂsches Vorhersagemodell entwickelt wurde. Dieses ist neben den Wedges auch fĂŒr die komplementĂ€re Multipolzerlegung sowohl des LDS als auch dessen Fouriertransformierten, der Zwei-Punkt-Korrelationsfunktion, anwendbar.
Die LDS-Analyse anhand von Clustering Wedges, wie in dieser Arbeit prĂ€sentiert, ist Teil der kombinierten Analyse des finalen Galaxienkatalogs im Rahmen der BOSS-Kollaboration. Unter Verwendung von zwei sich nicht ĂŒberschneidenden Rotverschiebungsbereichen wird die Winkeldurchmesserentfernung zu D_M(z_eff = 0.38) (rfid_d / r_d) = 1525 +-24 h^-1 Mpc und D_M(z_eff = 0.61) (rfid_d / r_d) = 2281 +42 -43 h^-1 Mpc bestimmt. Weiterhin wird der Hubbleparameter zu H(z_eff = 0.38) (r_d / rfid_d) = 81.2 +2.2 â2.3 km s^-1 Mpc^-1 und H(z_eff = 0.61) (r_d / rfid_d) = 94.9 +-2.5 km s^-1 Mpc^-1 vermessen (alle hier angegebenen Bereiche entsprechen einem Konfidenzintervall von 68%). Die
Wachstumsrate wird eingeschrĂ€nkt auf fÏ_8 (z_eff = 0.38) = 0.498 +0.044 -0.045 und fÏ_8 (z_eff = 0.61) = 0.409 +-0.040. Zusammen mit den Ergebnissen der komplementĂ€ren Methoden, die innerhalb der BOSS-Kollaboration zur Clustering-Analyse des finalen Galaxienkatalogs eingesetzt werden, werden diese Resultate zu einem abschlieĂenden Konsensergebnis zusammengefasst.
Nur mit den Clustering-Weges-Messungen im Fourierraum, kombiniert mit MWH- und SN-Daten, kann der Materiedichteparameter auf Ω_M = 0.311 +0.009
-0.010 und die Hubble-Konstante auf H_0 = 67.6 +0.7 -0.6 km s^-1 Mpc^â1 unter Annahme des ÎCDM-Modells eingeschrĂ€nken werden. Wird ein Nichtstandard-Modell fĂŒr DE angenommen, so ergibt sich ein DE-Zustandsgleichungsparameter von w_DE = 1.019 +0.048 -0.039. Modifikationen der Wachstumsrate, parametrisiert durch f(z) = [Ω_M(z)]^Îł, werden auf Îł = 0.52 +- 0.10 eingeschrĂ€nkt. Diese beiden Messungen sind in perfekter Ăbereinstimmung mit den Vorhersagen des ÎCDM-Modells, ebenso wie weitere Ergebnisse, die sich unter der Annahme eines noch groĂzĂŒgigeren DE-Modells (welches eine zeitliche Entwicklung von w_DE erlaubt) ergeben. Daher wird das ÎCDM-Modell durch die hier beschriebene Analyse weiter gefestigt.
Die Summe der Neutrinomassen wird zu sum(m_Îœ) < 0.143 eV bestimmt. Dieses obere Limit befindet sich nicht weit entfernt von der unteren Schranke, die sich aus Teilchenphysik-Experimenten ergibt. Somit ist zu erwarten, dass die kosmologische Signatur, die massebehaftete Neutrinos in der groĂskaligen Struktur des Universums hinterlassen, in naher Zukunft detektiert werden kann.Galaxy surveys cover a large fraction of the celestial sphere using modern multi-fibre spectrographs. Thanks to ever increasing datasets, the analysis of the large-scale structure (LSS) of the Universe has become a prolific source of cosmological information. Together with the observations of the cosmic microwave background (CMB) and samples of supernova (SN) of type Ia, they helped to establish the standard cosmological paradigm, the ÎCDM model. From the analysis of redshift-space galaxy clustering, the expansion history of the Universe can be inferred using the feature of Baryon Acoustic Oscillations (BAO) as a standard ruler to measure cosmic distances. The growth rate of cosmic structure can also be determined using redshift-space distortions (RSD). These measurements provide insight into competing alternatives of the ÎCDM model. The nature of the Dark Energy (DE), a strange component that is believed to be responsible for the current phase of accelerating expansion of the Universe, can be unravelled from BAO measurements of the late-time expansion. Modified theories of gravity can be constrained from the growth rate extracted from RSD, which can deviate from the prediction of general relativity.
The redshift measurements of the Baryon Acoustic Oscillation Survey (BOSS) program that was completed in 2014 yielded a galaxy sample that covers an unprecedented volume. In this thesis, the standard model and its most important extensions are analysed using the cosmological information in the full-shape of the redshift-space two-point statistics measured from the final BOSS galaxy sample. So far, anisotropic clustering analyses in Fourier space relied on power spectrum multipole measurements. For this work, the concept of clustering wedges was extended to Fourier space to establish a complementary approach to measure clustering anisotropies: we introduce the optimal-variance estimator for clustering wedges, which is designed to account for systematic weights that correct the observational incompleteness of the BOSS sample, and also develop the window function formalism for the wedges.
Our modelling of the anisotropic galaxy clustering is based on novel approaches for the description of non-linear gravitational dynamics and redshift-space distortions. This improved modelling allows us to include smaller scales in our full-shape fits than in previous BAO+RSD studies, resulting in tighter cosmological constraints. The galaxy clustering model is verified using synthetic catalogues based on large-volume N -body simulations. As this test requires a theoretical description for the anisotropic clustering covariance matrix, a Gaussian formalism was developed for that purpose. As a side project, this formalism is extended to describe clustering wedges and multipoles in Fourier and configuration space.
The Fourier-space clustering measurements presented in this thesis are part of the joint analysis of the final BOSS sample. Using two non-overlapping redshift bins, we measure an angular diameter distance of D_M(z_eff = 0.38) (rfid_d / r_d) = 1525 +-24 h^-1 Mpc and D_M(z_eff = 0.61) (rfid_d / r_d) = 2281 +42 -43 h^-1 Mpc, as well as a Hubble parameter of H(z_eff = 0.38) (r_d / rfid_d) = 81.2 +2.2 â2.3 km s^-1 Mpc^-1 and H(z_eff = 0.61) (r_d / rfid_d) = 94.9 +-2.5 km s^-1 Mpc^-1 (all limits correspond to the statistical error of a confidence level of 68%). The growth rate is constrained to fÏ_8 (z_eff = 0.38) = 0.498 +0.044 -0.045 und fÏ_8 (z_eff = 0.61) = 0.409 +-0.040. These measurements will be combined with the complementary results from other galaxy clustering methods in configuration and Fourier space in order to determine the final BOSS consensus measurements.
From our analysis alone, in combination with CMB and SN Ia data, we obtain a matter density parameter of Ω_M = 0.311 +0.009
-0.010 and a local Hubble parameter of H_0 = 67.6 +0.7 -0.6 km s^-1 Mpc^â1 assuming a ÎCDM cosmology. Allowing for a non-standard DE model, we find an equation-of-state parameter of w_DE = 1.019 +0.048 -0.039. Modifications of the growth rate, parametrized as f(z) = [Ω_M(z)]^Îł, are constrained to Îł = 0.52 ± 0.10. These two results, along with those obtained using a more general DE model to identify a time-evolution of w_DE, are in perfect agreement with the ÎCDM predictions. Thus, the standard paradigm is further consolidated by our analysis.
The sum of neutrino masses is found to be sum(m_Îœ) < 0.143 eV. As this limit is close to the lower bound from particle physics, a detection of the cosmological signature of massive neutrinos from LSS analyses can be expected in the near future.Deutsche Ăbersetzung des Titels: Anisotrope Messungen der Galaxien-HĂ€ufungsverteilung im Fourierraum und kosmologische Implikationen des BOSS-DR12-Galaxiensample
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