Circulating Amino Acids and Risk of Peripheral Artery Disease in the PREDIMED Trial

Effective prevention and risk prediction are important for peripheral artery disease (PAD) due to its poor prognosis and the huge disease burden it produces. Circulating amino acids (AA) and their metabolites may serve as biomarkers of PAD risk, but they have been scarcely investigated. The objective was to prospectively analyze the associations of baseline levels of plasma AA (and their pathways) with subsequent risk of PAD and the potential effect modification by a nutritional intervention with the Mediterranean diet (MedDiet). A matched case-control study was nested in the PREDIMED trial, in which participants were randomized to three arms: MedDiet with tree nut supplementation group, MedDiet with extra-virgin olive oil (EVOO) supplementation group or control group (low-fat diet). One hundred and sixty-seven PAD cases were matched with 250 controls. Plasma AA was measured with liquid chromatography/mass spectrometry at the Broad Institute. Baseline tryptophan, serine and threonine were inversely associated with PAD (ORfor 1 SD increase = 0.78 (0.61–0.99); 0.67 (0.51–0.86) and 0.75 (0.59–0.95), respectively) in a multivariable-adjusted conditional logistic regression model. The kynurenine/tryptophan ratio was directly associated with PAD (ORfor 1 SD increase = 1.50 (1.14–1.98)). The nutritional intervention with the MedDiet+nuts modified the association between threonine and PAD (p-value interaction = 0.018) compared with the control group. However, subjects allocated to the MedDiet+EVOO group were protected against PAD independently of baseline threonine. Plasma tryptophan, kynurenine/tryptophan ratio, serine and threonine might serve as early biomarkers of future PAD in subjects at a high risk of cardiovascular disease. The MedDiet supplemented with EVOO exerted a protective effect, regardless of baseline levels of threonine

Employment generation by small firms in Spain

Despite the relevance in terms of policy, we still know little in Spain about where and by whom jobs are created, and how that is affecting the size distribution of firms. The main innovation of this paper is to use a rich database that overcomes the problems encountered by other firm-level studies to shed some light on the employment generation of small firms in Spain. We find that small firms contribute to employment disproportionately across all sectors of the economy although the difference between their employment and job creation share is largest in the manufacturing sector. The job creators in that sector are both new and established firms whereas only new small firms outperform their larger counterparts in the service sector. The large annual job creation of the small firm size class is shifting the firm size distribution towards the very small production units, although not uniformly across industries of different technology intensit

Wage inequality, segregation by skill and the price of capital in an assignment model

Some pieces of empirical evidence suggest that in the U.S., over the last few decades, (i) wage inequality between-plants has risen much more than wage inequality within-plants and (ii) there has been an increase in the segregation of workers by skill into separate plants. This paper presents a frictionless assignment model in which these two features can be explained simultaneously as the result of the decline in the relative price of capital. Additional implications of the model regarding the skill premium and the dispersion in labor productivity across plants are also consistent with the empirical evidence. [resumen de autor

The labor market effects of technology shocks

We analyze the effects of neutral and investment-specific technology shocks on hours worked and unemployment. We characterize the response of unemployment in terms of job separation and job finding rates. We find that job separation rates mainly account for the impact response of unemployment while job finding rates for movements along its adjustment path. Neutral shocks increase unemployment and explain a substantial portion of unemployment and output volatilityinvestment-specific shocks expand employment and hours worked and mostly contribute to hours worked volatility. We show that this evidence is consistent with the view that neutral technological progress prompts Schumpeterian creative destruction, while investment specific technological progress has standard neoclassical feature

Elongated magnetic nanoparticles with high-aspect ratio: a nuclear relaxation and specific absorption rate investigation

Medical application of nanotechnology implies the development of nanomaterials capable of being functional in different biological environments. In this sense, elongated nanoparticles (e-MNPs) with high-aspect ratio have demonstrated more effective particle cellular internalization, which is favoured by the increased surface area. This paper makes use of an environmentally friendly hydrothermal method to produce magnetic iron oxide e-MNPs, starting from goethite precursors. At high temperatures (Td) goethite transforms into hematite, which subsequently reduces to magnetite when exposed to a hydrogen atmosphere for a certain time. It is shown that by adjusting Td it is possible to obtain Fe3O4 e-MNPs with partially controlled specific surface area and magnetic properties, attributed to different porosity of the samples. The particles' efficiencies for diagnostic and therapeutic purposes (in magnetic resonance imaging and magnetic fluid hyperthermia, respectively) are very good in terms of clinical standards, some samples showing transversal proton nuclear relaxivity r2 (B0 = 1.33 T) = 340 s-1 mM-1 and specific absorption rate SAR > 370 W g-1 at high field amplitudes (B0 = 55 mT). Direct correlations between the SAR, relaxivity, magnetic properties and porosity of the samples are found, and the physico-chemical processes underneath these correlations are investigated. Our results open the possibility of using very efficient high-aspect ratio elongated nanoparticles with optimized chemico-physical properties for biomedical applications

Joint Response to the House Judiciary Committee on the State of Antitrust Law and Implications for Protecting Competition in Digital Markets

Economic research establishes that market power is now a serious problem. Growing market power harms consumers and workers, slows innovation, and limits productivity growth. Market power is on the rise in a number of major industries, including, for example, airlines, brewing, and hospitals, where multiple horizontal mergers that were allowed to proceed without antitrust challenge have markedly increased concentration in important markets and facilitated the exercise of market power. Exclusionary conduct by dominant companies that stifles competition from actual and potential rivals — including nascent rivals with capabilities for challenging a dominant firm’s market power and firms with competing R&D efforts — impairs what is often the most important economic force creating competitive pressure for dominant firms. This concern exists in digital marketplaces. Platforms are often insulated from platform competition to a substantial extent by substantial scale economies in supply and demand (network effects) combined with customer switching costs.Courts have contributed to increased monopoly power through decisions that have weakened the prohibitions against anticompetitive exclusionary conduct and anticompetitive mergers. The antitrust laws, as interpreted and enforced today, are inadequate to confront and deter growing market power in the U.S. economy and unnecessarily limit the ability of antitrust enforcers to address anticompetitive conduct. Many key antitrust precedents — particularly those precedents governing exclusionary conduct — rely on unsound economic theories or unsupported empirical claims about the competitive effects of certain practices. In part for this reason, the antitrust rules constructed by the courts reflect a systematically skewed error cost balance: they are too concerned to avoid both chilling procompetitive conduct and the high costs of litigation, and too dismissive of the costs of failing to deter harmful conduct. Excessively permissive precedents and unsound or unsupported economic claims have, in turn, encouraged overly cautious enforcement policies and overly demanding proof requirements and have discouraged government enforcers and private plaintiffs from bringing meritorious exclusionary conduct cases. The statement discusses a number of legal rules that are unsupported by or inconsistent with sound economic research that have contributed to overly permissive rules.The signatories to this letter strongly believe that antitrust enforcement has become too lax, in large part because of the courts and that Congress must act to correct this problem. The statement suggests a number of reforms could be considered. We do not collectively or unanimously endorse any of these, though some of us have done so in other contexts. We do believe that Congress has a historic opportunity to identify adverse trends in judicial interpretation of the antitrust and correct problems—not just by overriding damaging precedents, but also by reshaping the antitrust laws more broadly to enhance deterrence of anticompetitive conduct