Influence of Atomic Surface Structure on the Activity of Ag for the Electrochemical Reduction of CO 2 to CO

The present work was undertaken to elucidate the facet-dependent activity of Ag for the electrochemical reduction of CO to CO. To this end, CO reduction was investigated over Ag thin films with (111), (100), and (110) orientations prepared via epitaxial growth on single-crystal Si wafers with the same crystallographic orientations. This preparation technique yielded larger area electrodes than can be achieved using single-crystals, which enabled the electrocatalytic activity of the corresponding Ag surfaces to be quantified in the Tafel regime. The Ag(110) thin films exhibited higher CO evolution activity compared to the Ag(111) and Ag(100) thin films, consistent with previous single-crystal studies. Density functional theory calculations suggest that CO reduction to CO is strongly facet-dependent, and that steps are more active than highly coordinated terraces. This is the result of both a higher binding energy of the key intermediate COOH as well as an enhanced double-layer electric field stabilization over undercoordinated surface atoms located at step edge defects. As a consequence, step edge defects likely dominate the CO reduction activity observed over the Ag(111) and Ag(100) thin films. The higher activity observed over the Ag(110) thin film is then related to the larger density of undercoordinated sites compared to the Ag(111) and Ag(100) thin films. Our conclusion that undercoordinated sites dominate the CO reduction activity observed over close-packed surfaces highlights the need to consider the contribution of such defects in studies of single-crystal electrodes. 2 2 2 2

Hadronic production of bottom-squark pairs with electroweak contributions

We present the complete computation of the tree-level and the next-to-leading order electroweak contributions to bottom-squark pair production at the LHC. The computation is performed within the minimal supersymmetric extension of the Standard Model. We discuss the numerical impact of these contributions in several supersymmetric scenarios.Comment: 33 pages, v2: preprint numbers correcte

Hadronic production of squark-squark pairs: The electroweak contributions

We compute the electroweak (EW) contributions to squark--squark pair production processes at the LHC within the framework of the Minimal Supersymmetric Standard Model (MSSM). Both tree-level EW contributions, of O(alpha_s alpha + alpha^2), and next-to-leading order (NLO) EW corrections, of O(alpha_s^2 alpha), are calculated. Depending on the flavor and chirality of the produced quarks, many interferences between EW-mediated and QCD-mediated diagrams give non-zero contributions at tree-level and NLO. We discuss the computational techniques and present an extensive numerical analysis for inclusive squark--squark production as well as for subsets and single processes. While the tree-level EW contributions to the integrated cross sections can reach the 20% level, the NLO EW corrections typically lower the LO prediction by a few percent.Comment: 36 pages, 18 figure

The highly rearranged mitochondrial genomes of the crabs Maja crispata and Maja squinado (Majidae) and gene order evolution in Brachyura

Abstract We sequenced the mitochondrial genomes of the spider crabs Maja crispata and Maja squinado (Majidae, Brachyura). Both genomes contain the whole set of 37 genes characteristic of Bilaterian genomes, encoded on both \u3b1- and \u3b2-strands. Both species exhibit the same gene order, which is unique among known animal genomes. In particular, all the genes located on the \u3b2-strand form a single block. This gene order was analysed together with the other nine gene orders known for the Brachyura. Our study confirms that the most widespread gene order (BraGO) represents the plesiomorphic condition for Brachyura and was established at the onset of this clade. All other gene orders are the result of transformational pathways originating from BraGO. The different gene orders exhibit variable levels of genes rearrangements, which involve only tRNAs or all types of genes. Local homoplastic arrangements were identified, while complete gene orders remain unique and represent signatures that can have a diagnostic value. Brachyura appear to be a hot-spot of gene order diversity within the phylum Arthropoda. Our analysis, allowed to track, for the first time, the fully evolutionary pathways producing the Brachyuran gene orders. This goal was achieved by coupling sophisticated bioinformatic tools with phylogenetic analysis

Investigating The Effect Of A Prolonged Gap 1 Phase On Specification Of Progenitors During Zebrafish Embryogenesis

The development of a vertebrate organism requires a single cell to become all of the cells that make up the adult, through the processes of proliferation and differentiation. A relationship has been observed between the cell cycle, specifically the gap phases, and a stem cell’s decision to remain undifferentiated or differentiate into a specific cell type. My research is focused on understanding this relationship by manipulating the cell cycle and observing the effects on vertebrate development. A transgenic line of zebrafish [tg(hsp70l:ccnd1DN)] allowed for prolonging the normally short gap 1 phase observed in stem cells by expressing a mutated form of cyclin D1. I determined the timing of heat induced gene expression from the transgene in order to understand how an altered gap phase affects the critical windows of tissue development during embryogenesis. Using this information, I looked at how expression of a gene involved in differentiation of sensory neurons changed with a manipulated gap 1 phase. The decrease in expression observed in transgenic organisms suggests that there is a relationship between the length of the first gap phase and specification of sensory neurons in zebrafish

Zoltán Kodály’s Op. 9, Öt dal: a historical, textual, and musical analysis with translations and IPA

Zoltán Kodály is primarily known outside of Hungary for his pedagogical work. However, his compositions should also be recognized for their excellence. His art songs for voice and piano, though mostly composed earlier in his career, represent an important contribution to the art song genre. Kodály was able to synthesize elements of foreign art song composers and his own folk culture to create an effective and important contribution to art song. He, along with Bartók, was one of the first and most significant Hungarian contributors to this genre. These works are rarely performed outside of Hungary due to language issues and availability. Through historical, textual, musical analysis, translations, and IPA, this dissertation will provide a performers’ guide for Kodály’s Op. 9 Öt dal. In addition, reasons for choosing Op. 9 include texts written by the contemporary poets Endre Ady and Béla Balázs, a lack of current scholarship, no complete English translations, and more compositional maturity while using Hungarian elements. This dissertation will allow more non-Hungarian musicians to teach and perform Kodály’s art songs

Developmental psychogenic mutism as a cause of severely delayed speech development

The purpose of this descriptive study is to posit information concerning "Developmental Psychogenic Mutism." The study has attempted to apply this descriptive term, Developmental Psychogenic Mutism, to certain children displaying severely delayed speech development of unknown etiology. Three children who were severely delayed in the acquisition of speech were selected as subjects for this study. The similarities they shared were compared and contrasted with four of the recognized causes of severely delayed speech development in an attempt to determine whether or not the descriptive term Developmental Psychogenic Mutism should be applied. Each subject was hospitalized in Amos Cottage for behavioral and diagnostic therapy in an attempt to determine potential. The case histories of each subject were presented, and each subject was studied in diagnostic therapy for a period of not less than four months. Tests of receptive abilities and performance were administered to each subject. The parents were also studied in an attempt to determine the intrafamilial relationships

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

JLab Measurements of the 3He Form Factors at Large Momentum Transfers

The charge and magnetic form factors, FC and FM, of 3He have been extracted in the kinematic range 25 fm-2 < Q2 < 61 fm-2 from elastic electron scattering by detecting 3He recoil nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements are indicative of a second diffraction minimum for the magnetic form factor, which was predicted in the Q2 range of this experiment, and of a continuing diffractive structure for the charge form factor. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem

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