Non-invasive beam monitoring with harmonic cavities

NON INVASIVE BEAM MONITORING WITH HARMONIC CAVITIES by Brock Franklin Roberts B.S PHYSICS, UNIVERSITY OF CALIFORNIA DAVIS, 1992 DOCTOR OF PHILOSOPHY IN ELECTRICAL ENGINEERING UNIVERSITY OF NEW MEXICO, 2019 ABSTRACT A cavity designed to have multiple harmonic TM0N0 modes can be used to accurately measure the longitudinal profile of a bunched charged particle beam passing through its bore, non-invasively, and in real time. Multi-harmonic TM0N0 cavities were designed, constructed, and beamline tested in a variety of experiments at the Thomas Jefferson National Accelerator Facility (TJNAF or Jlab). Measurements with a sampling oscilloscope provided signals that resemble the profile of electron bunches passing through the cavity’s bore. Straightforward signal processing techniques reduce distortion in the measurement and provide real time profiles of electron bunches with picosecond accuracy. Subharmonic beams having bunch repetition rates of 1/3rd and 1/6th of Jlab’s 1497 MHz bunch frequency, and interleaved sub-harmonic beams were also measured. Comparison between measurements made using a harmonic cavity were corroborated with an established invasive measurement method and with computer models. A harmonic cavity from this effort has been installed within the CEBAF injector, allowing accelerator operators to view, in real time, the shape and duration of electron bunches entering the accelerator. Another harmonic cavity has been installed within Jlab’s Upgraded Injector Test Facility (UITF), and two more are planned for installation there. This effort was awarded the 2016 International Beam Instrumentation Conference’s Faraday Cup Award

3-manifolds efficiently bound 4-manifolds

It is known since 1954 that every 3-manifold bounds a 4-manifold. Thus, for instance, every 3-manifold has a surgery diagram. There are several proofs of this fact, including constructive proofs, but there has been little attention to the complexity of the 4-manifold produced. Given a 3-manifold M of complexity n, we show how to construct a 4-manifold bounded by M of complexity O(n^2). Here we measure ``complexity'' of a piecewise-linear manifold by the minimum number of n-simplices in a triangulation. It is an open question whether this quadratic bound can be replaced by a linear bound. The proof goes through the notion of "shadow complexity" of a 3-manifold M. A shadow of M is a well-behaved 2-dimensional spine of a 4-manifold bounded by M. We prove that, for a manifold M satisfying the Geometrization Conjecture with Gromov norm G and shadow complexity S, c_1 G <= S <= c_2 G^2 for suitable constants c_1, c_2. In particular, the manifolds with shadow complexity 0 are the graph manifolds.Comment: 39 pages, 21 figures; added proof for spin case as wel

An Economic Analysis of Twitching Behaviour and Species Rarity

Avid birdwatchers, or ‘twitchers’, expend a considerable amount of money and time pursuing viewing experiences of rare or vagrant species. By vagrant species we mean a species found outside its normal range/distribution. To enhance our understanding of this form of behaviour, we present results from a UK survey of twitchers. First, we examine the relationship between cost and rarity based on actual viewing experiences. Our statistical results reveal that the relationship between cost and rarity is positive and very inelastic. Second, we present results from a hypothetical Best-Worst Scaling exercise examining aspects of species rarity. We find that rarity is a more nuanced construct than simply the frequency with which a vagrant species has appeared. Our results provide insights into the meaning of rarity, as well as the economic value attach to it and why

The economics of species extinction: An economist’s viewpoint

There is growing evidence to suggest that there is an increase in species extinction occurring globally. In this article, we briefly review the literature on the economics of species extinction, examining what is meant by extinction before explaining how economics has conceptualised this. The initial economics literature on species extinction focuses largely on renewable resources, in particular fisheries, but has subsequently evolved to cover many aspects of biodiversity across all physical scales, employing an increasing array of methodological tools. We also consider aspects of cultural and societal extinctions (e.g. local languages, local knowledge) and how this is positively correlated with loss of biodiversity, as well as an economist’s outlook on the potential to re-capture value post-extinction

Generalized Markoff Maps and McShane's Identity

We study general representations of the free group on two generators into $SL(2,C)$, and the connection with generalized Markoff maps, following Bowditch. We show that Bowditch's Q-conditions for generalized Markoff maps are sufficient for the generalized McShane identity to hold for the corresponding representations and that the subset of representations satisfying these conditions is the largest open subset in the relative character variety on which the mapping class group acts properly discontinuously. Moreover we generalize Bowditch's results on variations of McShane's identity for complete, finite volume hyperbolic 3-manifolds which fiber over the circle, with the fiber a punctured-torus, to identities for incomplete hyperbolic structures on such manifolds, hence obtaining identities for closed hyperbolic 3-manifolds which are obtained by doing hyperbolic Dehn surgery on such manifolds.Comment: 49 pages, 9 figure

An exploratory investigation of endotoxin levels in novice long distance triathletes, and the effects of a multi-strain probiotic/prebiotic, antioxidant intervention.

Abstract: Gastrointestinal (GI) ischemia during exercise is associated with luminal permeability and increased systemic lipopolysaccharides (LPS). This study aimed to assess the impact of a multistrain pro/prebiotic/ antioxidant intervention on endotoxin unit levels and GI permeability in recreational athletes. Thirty healthy participants (25 males, 5 females) were randomly assigned either a multistrain pro/prebiotic/ antioxidant (LAB4ANTI; 30 billion CFU.d-1 containing 10 billion CFU.d-1 Lactobacillus acidophilus CUL-60 [NCIMB 30157], 10 billion CFU.d-1 Lactobacillus acidophillus CUL-21 [NCIMB 30156], 9.5 billion CFU.d-1 Bifidobacterium bifidum CUL-20 [NCIMB 30172] and 0.5 billion CFU.d-1 Bifidobacterium animalis subspecies lactis CUL-34 [NCIMB 30153]/ 55.8 mg.d-1 fructooligosaccharides/ 400 mg.d-1 α-lipoic acid, 600 mg.d-1 N-acetyl-carnitine); matched pro/prebiotic (LAB4) or placebo (PL) for 12 weeks preceding a long-distance triathlon. Plasma endotoxin units (via Limulus amebocyte lysate chromogenic quantification) and GI permeability (via 5 hour urinary lactulose (L): mannitol (M) recovery) were assessed at baseline, pre-race and 6 days post-race. Endotoxin unit levels were not significantly different between groups at baseline (LAB4ANTI: 8.20±1.60 pg.ml-1; LAB4: 8.92±1.20 pg.ml-1; PL: 9.72± 2.42 pg.ml-1). The use of a 12 week LAB4ANTI intervention significantly reduced endotoxin units both pre-race (4.37± 0.51 pg.ml-1) and 6 days post-race (5.18±0.57 pg.ml-1; p=0.03, ηp2 = 0.35), but only 6 days post-race with LAB4 (5.01± 0.28 pg.ml-1; p=0.01, ηp2 = 0.43). In contrast, endotoxin units remained unchanged with PL. L:M significantly increased from 0.01±0.01 at baseline to 0.06± 0.01 with PL only (p=0.004, ηp2 = 0.51). Mean race times (hr:min:sec) were not statistically different between groups despite faster times with both pro/prebiotoic groups (LAB4ANTI:13:17:07±34:48; LAB4: 12:47:13±25:06; PL: 14:12:51±29:54; p>0.05). Combined multistrain pro/prebiotic use may reduce endotoxin unit levels, with LAB4ANTI potentially conferring an additive effect via combined GI modulation and antioxidant protection

A Critical Phenylalanine Residue in the Respiratory Syncytial Virus Fusion Protein Cytoplasmic Tail Mediates Assembly of Internal Viral Proteins into Viral Filaments and Particles

Respiratory syncytial virus (RSV) is a single-stranded RNA virus in the Paramyxoviridae family that assembles into filamentous structures at the apical surface of polarized epithelial cells. These filaments contain viral genomic RNA and structural proteins, including the fusion (F) protein, matrix (M) protein, nucleoprotein (N), and phosphoprotein (P), while excluding F-actin. It is known that the F protein cytoplasmic tail (FCT) is necessary for filament formation, but the mechanism by which the FCT mediates assembly into filaments is not clear. We hypothesized that the FCT is necessary for interactions with other viral proteins in order to form filaments. In order to test this idea, we expressed the F protein with cytoplasmic tail (CT) truncations or specific point mutations and determined the abilities of these variant F proteins to form filaments independent of viral infection when coexpressed with M, N, and P. Deletion of the terminal three FCT residues (amino acids Phe-Ser-Asn) or mutation of the Phe residue resulted in a loss of filament formation but did not affect F-protein expression or trafficking to the cell surface. Filament formation could be restored by addition of residues Phe-Ser-Asn to an FCT deletion mutant and was unaffected by mutations to Ser or Asn residues. Second, deletion of residues Phe-Ser-Asn or mutation of the Phe residue resulted in a loss of M, N, and P incorporation into virus-like particles. These data suggest that a C-terminal Phe residue in the FCT mediates assembly through incorporation of internal virion proteins into virus filaments at the cell surface

Atmospheric emissions from the deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate

The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas-oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (∼258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air-water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (∼33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (∼14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid-response airborne assessment of future oil spills. Copyright 2011 by the American Geophysical Union

The non-linear response of the magnetosphere: 30 October 1978

Previous efforts to find evidence of deterministic nonlinear dynamics in the global geomagnetic system have treated the geomagnetic system as autonomous. However, the geomagnetic system is strongly driven by the stochastic solar wind. We consider the response of the magnetosphere, as given by the AE index, for one day when the IMF had a nearly constant southward value. Using both a series of non-linear statistics and non-linear prediction of the response to the input signal $v B_s$, we find that there is some evidence for deterministic non-linear response of the Earth's magnetosphere on that day.Comment: 4 pages, Postscript file compressed and uuencoded, made with uufiles scrip