942 research outputs found
A Traditional and Textualist Analysis of the Goals of Antitrust: Efficiency, Preventing Theft from Consumers, and Consumer Choice
This Article ascertains the overall purpose of the antitrust statutes in two very different ways. First, it performs a traditional analysis of the legislative history of the antitrust laws by analyzing relevant legislative debates and committee reports. Second, it undertakes a textualist or “plain meaning” analysis of the purpose of the antitrust statutes, using Justice Scalia’s methodology. It does this by analyzing the meaning of key terms as they were used in contemporary dictionaries, legal treatises, common law cases, and the earliest U.S. antitrust cases, and it does this in light of the history of the relevant times.
Both approaches demonstrate that the overriding purpose of the antitrust statutes is to prevent firms from stealing from consumers by charging them supracompetitive prices. When firms use their market power to raise prices to supracompetitive levels, purchasers pay more for their goods and services, and these overcharges constitute a taking of purchasers’ property. Economic efficiency was only a secondary concern. In addition, the textualist approach leads to the surprising conclusion that neither the Sherman Act nor the Clayton Act contain an exception for monopolies attained by efficient business conduct. A “plain meaning” analysis of the antitrust statutes reveals that they are supposed to prevent and condemn all privately created monopolies
Nicola Masciandaro (ed.): Hideous Gnosis. Black Metal Theory Symposium I
Metal studies is an ever-growing field within academia, with annual conferences being held and new publications appearing fairly regularly. However, theory and methodology are two fields of research that have not yet been much discussed. Frequent criticism of metal studies often focuses on a lack of theoretical as well as methodological engagement – an accusation of being unscientific. There has been some work focusing on this problem and trying to deal with it – mostly sociological and music..
A study on the structure and vibrations of diphenylamine by resonance-enhanced multiphoton ionization spectroscopy and ab initio calculations
Laser‐desorption jet‐cooling has been applied in combination with mass‐selective gas‐phase spectroscopic techniques to study the structure and low‐frequency vibrations of diphenylamine (DPA). Two‐color (1+1′) resonance‐enhanced multiphoton ionization has been used to measure the vibrationally resolved excitation spectrum of the S1←S0 transition in the 305–309 nm region. Ion‐dip measurements have been performed to determine the vibrational structure in the electronic ground state. The electronic spectra of DPA are dominated by long progressions in low‐frequency vibrations involving the motion of the phenyl rings as a whole. For the interpretation of the experimental data ab initio calculations have been performed at the Hartree–Fock level for the S0‐state and using single‐excitation configuration interaction for the S1‐state. The DPA molecule is found to change from a pyramidal geometry around the N‐atom with unequal torsional angles of the phenyl groups in the S0‐state to a planar geometry with equal torsional angles in the S1‐state. The two most prominent vibrational motions are the in‐phase wagging and the in‐phase torsion of the phenyl rings. In addition, the resonance‐enhanced multiphoton ionization spectra of the S1←S0 transition in the DPA‐Ar, DPA‐Kr, and DPA‐Xe van der Waals complexes have been measured. From these spectra it is inferred that there is a coupling between the van der Waals modes and the low‐frequency intra‐molecular modes of DPA
Infrared spectroscopy of jet-cooled neutral and ionized aniline-Ar
We report the infrared (IR) absorption spectrum of the jet-cooled neutral aniline–Ar Van der Waals complex together with that of the aniline–Ar cation in the 350–1700 cm−1 range. The spectra are measured using mass-selective ion detection in two different IR–ultraviolet double-resonance excitation schemes, using a free-electron laser as a source of widely tunable, intense IR radiation. A comparison with calculated IR spectra of the bare neutral aniline and of the cation of aniline allows for an unambiguous assignment of all the observed modes. The dissociation limit of the neutral aniline–Ar complex is bracketed between 273 and 329 cm−1, significantly lower than previously estimated. <br
Nicola Masciandaro (ed.): Hideous Gnosis. Black Metal Theory Symposium I
Metal studies is an ever-growing field within academia, with annual conferences being held and new publications appearing fairly regularly. However, theory and methodology are two fields of research that have not yet been much discussed. Frequent criticism of metal studies often focuses on a lack of theoretical as well as methodological engagement – an accusation of being unscientific. There has been some work focusing on this problem and trying to deal with it – mostly sociological and music..
The infrared spectrum of the benzene–Ar cation
The infrared (IR) absorption spectra of the jet-cooled C6H6 and C6D6 cations, complexed with Ar, are measured throughout the 450–1500 cm−1 region via IR-laser-induced vibrational dissociation spectroscopy. The IR spectrum of the C6H6–Ar cation is dominated by a Fermi resonance between the IR active v11 mode and two components of the combination mode of the lowest frequency modes v6 and v16 . A stringent upper limit of 316 cm−1 is found for the value of the dissociation limit D0 of the neutral C6D6–Ar complex
The role of the mobile proton in fucose migration
Fucose migration reactions represent a substantial challenge in the analysis of fucosylated glycan structures by mass spectrometry. In addition to the well-established observation of transposed fucose residues in glycan-dissociation product ions, recent experiments show that the rearrangement can also occur in intact glycan ions. These results suggest a low-energy barrier for migration of the fucose residue and broaden the relevance of fucose migration to include other types of mass spectrometry experiments, including ion mobility-mass spectrometry and ion spectroscopy. In this work, we utilize cold-ion infrared spectroscopy to provide further insight into glycan scrambling in intact glycan ions. Our results show that the mobility of the proton is a prerequisite for the migration reaction. For the prototypical fucosylated glycans Lewis x and blood group antigen H-2, the formation of adduct ions or the addition of functional groups with variable proton affinity yields significant differences in the infrared spectra. These changes correlate well with the promotion or inhibition of fucose migration through the presence or absence of a mobile proton
The structure and energetics of He and He nanodroplets doped with alkaline earth atoms
We present systematic results, based on density functional calculations, for
the structure and energetics of He and He nanodroplets doped with
alkaline earth atoms. We predict that alkaline earth atoms from Mg to Ba go to
the center of He drops, whereas Ca, Sr, and Ba reside in a deep dimple at
the surface of He drops, and Mg is at their center. For Ca and Sr, the
structure of the dimples is shown to be very sensitive to the He-alkaline earth
pair potentials used in the calculations. The transition
of strontium atoms attached to helium nanodroplets of either isotope has been
probed in absorption experiments. The spectra show that strontium is solvated
inside He nanodroplets, supporting the calculations. In the light of our
findings, we emphasize the relevance of the heavier alkaline earth atoms for
analyzing mixed He-He nanodroplets, and in particular, we suggest their
use to experimentally probe the He-He interface.Comment: Typeset using Revtex, 20 pages and 8 Postscript file
IR SPECTROSCOPY ON PEPTIDES AND PROTEINS AFTER ION MOBILITY SELECTION AND IN LIQUID HELIUM DROPLETS
IR spectroscopy has become a frequently used tool to characterize gas-phase peptides and proteins. In many experiments, ions are m/z selected, irradiated by intense and tunable IR light and fragmentation is monitored as a function of IR wavelength. The presence of different conformers can, however, complicate the interpretation, as the resulting spectra represent the sum of the spectra of the individual components. We constructed a setup, in which ion mobility methods are used to obtain m/z selected ions of defined shape on which are then further investigated by IR spectroscopy. First results on peptide aggregates are presented and for some of those, the IR spectra show a transition from helical or random coil to beta sheet structures.\
In a different experiment, peptide or protein ions are captures in liquid helium droplets prior to IR spectroscopic investigation. The conditions inside a helium droplet are isothermal at 0.38 K and the interaction between the helium matrix and the molecules are weak so that only small perturbations on the molecule are expected. IR spectra for m/z selected peptides with up to 10 aminoacids and proteins containing more than 100 aminoacids have been measured. The spectra of the smaller species show resolved bands of individual oscillators, which can be used for structure assignment. For the larger species, band envelopes are obtained and for the case of highly charged proteins, a transition form helical to extended structures is observed
Efeito de partículas metálicas liberadas dos implantes dentários sobre os tecidos periimplantares
TCC (graduação) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Odontologia.Atualmente o uso de implantes dentários é uma alternativa terapêutica de grande relevância para o tratamento de ausências dentárias e a tendência é que esse tratamento se torne cada vez mais frequente, devido ao aumento da previsibilidade, segurança e taxa de sobrevida dos implantes nos últimos anos. O material mais utilizado para a produção de implantes dentários é o titânio comercialmente puro, devido à sua alta resistência mecânica, alta resistência à corrosão e ótima biocompatibilidade, que confere grande chance de osseointegração. Entretanto partículas metálicas liberadas a partir dos implantes após contato com substâncias terapêuticas e/ou orais corrosivas tem potencial de causar danos aos tecidos peri-implantares. O objetivo deste trabalho foi realizar uma revisão da literatura a respeito dos efeitos das partículas metálicas liberadas sobre os tecidos periimplantares como consequência do uso de técnicas terapêuticas empregadas no tratamento de doenças peri-implantares e/ou pela degradação do implante. Para a elaboração deste trabalho, foi realizado um levantamento bibliográfico, por meio de pesquisas em livros textos e pesquisas nas bases de dados Scielo e Pubmed. Foram selecionados 91 artigos científicos publicados entre os anos de 1977 e 2015. Os principais resultados encontrados nos estudos foram: a liberação de citocinas pró-inflamatórias, infiltrado de células de resposta inflamatória e ativação da atividade de osteoclastos nos tecidos periimplantares em contato com partículas e íons metálicos; alterações degenerativas em macrófagos e neutrófilos que fagocitaram micropartículas de titânio; mutações em células humanas em cultura contendo nanopartículas de TiO2. Conclui-se a partir dos dados encontrados na literatura que as partículas metálicas liberadas a partir do sistema de implantes têm potencial citotóxico e genotóxico e são capazes de induzir resposta inflamatória nos tecidos periimplantares
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