An analysis of binocular slant contrast

When a small frontoparallel surface (a test strip) is surrounded by a larger slanted surface (an inducer), the test strip is perceived as slanted in the direction opposite to the inducer. This has been called the depth-contrast effect, but we call it the slant-contrast effect. In nearly all demonstrations of this effect, the inducers slant is specified by stereoscopic signals, and other signals, such as the texture gradient, specify that it is frontoparallel. We present a theory of slant estimation that determines surface slant via linear combination of various slant estimators; the weight of each estimator is proportional to its reliability. The theory explains slant contrast because the absolute slant of the inducer and the relative slant between test strip and inducer are both estimated with greater reliability than the absolute slant of the test strip. The theory predicts that slant contrast will be eliminated if the signals specifying the inducers slant are consistent with one another. It also predicts reversed slant contrast if the inducers slant is specified by nonstereoscopic signals rather than by stereo signals. These predictions were tested and confirmed in three experiments. The first showed that slant contrast is greatly reduced when the stereo- and nonstereo-specified slants of the inducer are made consistent with one another. The second showed that slant contrast is eliminated altogether when the stimulus consists of real planes rather than images on a display screen. The third showed that slant contrast is reversed when the nonstereo-specified slant of the inducer varies and the stereo-specified slant is zero. We conclude that slant contrast is a byproduct of the visual systems reconciliation of conflicting information while it attempts to determine surface slant

Opening a new window to other worlds with spectropolarimetry

A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of SEARCH include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, SEARCH will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 meters along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom

Fifteen new risk loci for coronary artery disease highlight arterial-wall-specific mechanisms

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although 58 genomic regions have been associated with CAD thus far, most of the heritability is unexplained, indicating that additional susceptibility loci await identification. An efficient discovery strategy may be larger-scale evaluation of promising associations suggested by genome-wide association studies (GWAS). Hence, we genotyped 56,309 participants using a targeted gene array derived from earlier GWAS results and performed meta-analysis of results with 194,427 participants previously genotyped, totaling 88,192 CAD cases and 162,544 controls. We identified 25 new SNP-CAD associations (P < 5 × 10(-8), in fixed-effects meta-analysis) from 15 genomic regions, including SNPs in or near genes involved in cellular adhesion, leukocyte migration and atherosclerosis (PECAM1, rs1867624), coagulation and inflammation (PROCR, rs867186 (p.Ser219Gly)) and vascular smooth muscle cell differentiation (LMOD1, rs2820315). Correlation of these regions with cell-type-specific gene expression and plasma protein levels sheds light on potential disease mechanisms

Essays on Trade Credit

<p>This dissertation investigates how variation in trade credit standards play a role in firm maturation. In Chapter 1, I survey existing research in trade credit. Following this, I identify lifecycle trends in supplier trade credit policy in Chapter 2. Young suppliers assume greater risks in trade credit provision early in their lifecycles in order to advance growth and product market agendas. There is a peak around a supplier's IPO in the riskiness of trade credit supplied, measured by doubtful receivables and the length of credit provided (receivables length). I find that young firms in industries where customer-supplier relationships are more significant have higher doubtful receivables, consistent with suppliers varying trade credit standards to build relationships. Additionally, young suppliers with more complex products (as measured by R&D intensity) offer longer duration loans compared to suppliers of similar age. Offering riskier trade credit terms affects economic outcomes. In Chapter 3, I study if varying trade credit standards for the purpose of relationship building is a viable strategy for all firm maturities. I use the incidence of a major free trade agreement to study firm responses to a major disruption in existing supplier-customer relationships. Chapter 3 posits both supplier driven as well as customer driven explanations for the observed responses, finding evidence consistent with older suppliers have a reduced incentive as well as capacity to engage in relationship building.</p>Dissertatio

Nomenclature and taxonomy of Croton glabellus L. (Euphorbiaceae), a widespread Caribbean species

The application of the names Croton glabellus, C. lucidus, and Phyllanthus glabellus has been confusing since the earliest publications that used them. After a thorough review of these publications and corresponding herbarium specimens, we clarify the nomenclatural confusion surrounding these names and their taxonomy. We identify a new name, Phyllanthus glabellus Fawc. & Rendle, that was inadvertently made. We make the new combination Croton glabellus subsp. polytrichus, and we designate lectotypes for Astrocasia tremula, Croton subsect. Astraeopsis, C. glandulifer, C. lucidus var. polytrichus, and C. spicatus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146901/1/tax605029.pd

A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae)

Croton (Euphorbiaceae) is a large and diverse group of plants that is most species‐rich in the tropics. We update the infrageneric classification of the New World species of Croton with new evidence from phylogenetic analyses of DNA sequence data from all three genomes. The relationships of species that were previously placed in conflicting positions by nuclear and chloroplast data, such as C. cupreatus, C. poecilanthus, and C. setiger, are further resolved by adding the nuclear EMB2765 and mitochondrial rps3 genes to the molecular sampling. Analyses of rps3 reveal an accelerated rate of evolution within Croton subg. Geiseleria, the only one of the four subgenera that contains numerous herbaceous, annual species. We provide morphological descriptions, species lists, and a key to the 31 sections and 10 subsections recognized in the New World. New taxa that we describe include C. sects. Alabamenses, Argyranthemi, Cordiifolii, Corinthii, Cupreati, Luetzelburgiorum, Nubigeni, Olivacei, Pachypodi, Prisci, and C. subsects. Cubenses, Jamaicenses, and Sellowiorum. Additional transfers are made to the ranks of subgenus, section, and subsection. A total of 712 species of Croton are currently recognized for the New World, with 702 of them assigned here to section.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146834/1/tax603013.pd

Search for Second-Generation Scalar Leptoquarks in ppˉ\bm{p \bar{p}} Collisions at s\sqrt{s}=1.96 TeV

Results on a search for pair production of second generation scalar leptoquark in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb$^{-1}$. Leptoquarks (LQ) are sought through their decay into (charged) leptons and quarks, with final state signatures represented by two muons and jets and one muon, large transverse missing energy and jets. We observe no evidence for $LQ$ production and derive 95% C.L. upper limits on the $LQ$ production cross sections as well as lower limits on their mass as a function of $\beta$, where $\beta$ is the branching fraction for $LQ \to \mu q$.Comment: 9 pages (3 author list) 5 figure

Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page

Measurement of the B0 anti-B0 oscillation frequency using l- D*+ pairs and lepton flavor tags

The oscillation frequency Delta-md of B0 anti-B0 mixing is measured using the partially reconstructed semileptonic decay anti-B0 -> l- nubar D*+ X. The data sample was collected with the CDF detector at the Fermilab Tevatron collider during 1992 - 1995 by triggering on the existence of two lepton candidates in an event, and corresponds to about 110 pb-1 of pbar p collisions at sqrt(s) = 1.8 TeV. We estimate the proper decay time of the anti-B0 meson from the measured decay length and reconstructed momentum of the l- D*+ system. The charge of the lepton in the final state identifies the flavor of the anti-B0 meson at its decay. The second lepton in the event is used to infer the flavor of the anti-B0 meson at production. We measure the oscillation frequency to be Delta-md = 0.516 +/- 0.099 +0.029 -0.035 ps-1, where the first uncertainty is statistical and the second is systematic.Comment: 30 pages, 7 figures. Submitted to Physical Review

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente