Private Debt Overhang and the Government Spending Multiplier: Evidence for the United States

Using state-dependent local projection methods and historical U.S. data, we find that government spending multipliers are considerably larger in periods of private debt overhang. In particular, we find significant crowding-out of personal consumption and investment in low-debt states, resulting in multipliers that are significantly below one. Conversely, in periods of private debt overhang, there is a strong crowding-in effect, while multipliers are much larger than one. In high-debt states, more (less) government purchases also reduce (increase) the government debt-to-GDP ratio. These results are robust for the type of government spending shocks, and when we control for the business cycle, government debt overhang and the zero lower bound on the nominal interest rate. Our findings imply that spending multipliers were likely much larger than average during the Great Recession

Heterogeneous Government Spending Multipliers in the Era Surrounding the Great Recession

We use a novel quarterly dataset of U.S. states to examine the dynamics and determinants of relative government spending multipliers in the decade surrounding the Great Recession. We find average multipliers that are similar to those that have been reported for the decades preceding the crisis, but this masks substantial heterogeneity. First, average cumulative multipliers were around 2 in the impact quarter, but declined to less than 1 after one year. Second, implied relative multipliers ranged between 0 and more than 4 across states at particular points in time, as well as for the same state at different moments within the sample period depending on the individual state’s stance of the business cycle, household indebtedness and the interaction of both conditions. Finally, we provide evidence that, controlling for total expenditures, a mere redistribution of government spending across states did also had a significant influence on the aggregate U.S. economy due to cross-state heterogeneity of the effects

Effect of external PEEP in patients under controlled mechanical ventilation with an auto-PEEP of 5 cmH2O or higher.

In some patients with auto-positive end-expiratory pressure (auto-PEEP), application of PEEP lower than auto-PEEP maintains a constant total PEEP, therefore reducing the inspiratory threshold load without detrimental cardiovascular or respiratory effects. We refer to these patients as complete PEEP-absorbers. Conversely, adverse effects of PEEP application could occur in patients with auto-PEEP when the total PEEP rises as a consequence. From a pathophysiological perspective, all subjects with flow limitation are expected to be complete PEEP-absorbers, whereas PEEP should increase total PEEP in all other patients. This study aimed to empirically assess the extent to which flow limitation alone explains a complete PEEP-absorber behavior (i.e., absence of further hyperinflation with PEEP), and to identify other factors associated with it.One hundred patients with auto-PEEP of at least 5 cmH2O at zero end-expiratory pressure (ZEEP) during controlled mechanical ventilation were enrolled. Total PEEP (i.e., end-expiratory plateau pressure) was measured both at ZEEP and after applied PEEP equal to 80 % of auto-PEEP measured at ZEEP. All measurements were repeated three times, and the average value was used for analysis.Forty-seven percent of the patients suffered from chronic pulmonary disease and 52 % from acute pulmonary disease; 61 % showed flow limitation at ZEEP, assessed by manual compression of the abdomen. The mean total PEEP was 7 ± 2 cmH2O at ZEEP and 9 ± 2 cmH2O after the application of PEEP (p < 0.001). Thirty-three percent of the patients were complete PEEP-absorbers. Multiple logistic regression was used to predict the behavior of complete PEEP-absorber. The best model included a respiratory rate lower than 20 breaths/min and the presence of flow limitation. The predictive ability of the model was excellent, with an overoptimism-corrected area under the receiver operating characteristics curve of 0.89 (95 % CI 0.80-0.97).Expiratory flow limitation was associated with both high and complete PEEP-absorber behavior, but setting a relatively high respiratory rate on the ventilator can prevent from observing complete PEEP-absorption. Therefore, the effect of PEEP application in patients with auto-PEEP can be accurately predicted at the bedside by measuring the respiratory rate and observing the flow-volume loop during manual compression of the abdomen

Altered Modulation of Silent Period in Tongue Motor Cortex of Persistent Developmental Stuttering in Relation to Stuttering Severity

Motor balance in developmental stuttering (DS) was investigated with Transcranial Magnetic Stimulation (TMS), with the aim to define novel neural markers of persistent DS in adulthood. Eleven DS adult males were evaluated with TMS on tongue primary motor cortex, compared to 15 matched fluent speakers, in a "state" condition (i.e. stutterers vs. fluent speakers, no overt stuttering). Motor and silent period thresholds (SPT), recruitment curves, and silent period durations were acquired by recording tongue motor evoked potentials. Tongue silent period duration was increased in DS, especially in the left hemisphere (P<0.05; Hedge's g or Cohen's dunbiased = 1.054, i.e. large effect size), suggesting a "state" condition of higher intracortical inhibition in left motor cortex networks. Differences in motor thresholds (different excitatory/inhibitory ratios in DS) were evident, as well as significant differences in SPT. In fluent speakers, the left hemisphere may be marginally more excitable than the right one in motor thresholds at lower muscular activation, while active motor thresholds and SPT were higher in the left hemisphere of DS with respect to the right one, resulting also in a positive correlation with stuttering severity. Pre-TMS electromyography data gave overlapping evidence. Findings suggest the existence of a complex intracortical balance in DS tongue primary motor cortex, with a particular interplay between excitatory and inhibitory mechanisms, also in neural substrates related to silent periods. Findings are discussed with respect to functional and structural impairments in stuttering, and are also proposed as novel neural markers of a stuttering "state" in persistent DS, helping to define more focused treatments (e.g. neuro-modulation)

New Rigidity Results for Critical Metrics of Some Quadratic Curvature Functionals

We prove a new rigidity result for metrics defined on closed smooth $n$-manifolds that are critical for the quadratic functional $\mathfrak{F}_{t}$, which depends on the Ricci curvature $Ric$ and the scalar curvature $R$, and that satisfy a pinching condition of the form $Sec > \epsilon R$, where $\epsilon$ is a function of $t$ and $n$, while $Sec$ denotes the sectional curvature. In particular, we show that Bach-flat metrics with constant scalar curvature satisfying $Sec > \frac{1}{48} R$ are Einstein and, by a known result, are isometric to $\mathbb{S}^{4}$, $\mathbb{RP}^{4}$ or $\mathbb{CP}^{2}$.Comment: 17 page

Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

International audienceIn this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO 2 and dopant ion implantation. The process entails four successive steps: (i) Ge sputtering on SiO 2 , (ii) implantation preannealing, (iii) high-dose dopant implantation, and (iv) implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions

Association between a genetic variant of type-1 cannabinoid receptor and inflammatory neurodegeneration in multiple sclerosis

Genetic ablation of type-1 cannabinoid receptors (CB1Rs) exacerbates the neurodegenerative damage of experimental autoimmune encephalomyelitis, the rodent model of multiple sclerosis (MS). To address the role on CB1Rs in the pathophysiology of human MS, we first investigated the impact of AAT trinucleotide short tandem repeat polymorphism of CNR1 gene on CB1R cell expression, and secondly on the inflammatory neurodegeneration process responsible for irreversible disability in MS patients. We found that MS patients with long AAT repeats within the CNR1 gene (≥12 in both alleles) had more pronounced neuronal degeneration in response to inflammatory white matter damage both in the optic nerve and in the cortex. Optical Coherence Tomography (OCT), in fact, showed more severe alterations of the retinal nerve fiber layer (RNFL) thickness and of the macular volume (MV) after an episode of optic neuritis in MS patients carrying the long AAT genotype of CNR1. MS patients with long AAT repeats also had magnetic resonance imaging (MRI) evidence of increased gray matter damage in response to inflammatory lesions of the white matter, especially in areas with a major role in cognition. In parallel, visual abilities evaluated at the low contrast acuity test, and cognitive performances were negatively influenced by the long AAT CNR1 genotype in our sample of MS patients. Our results demonstrate the biological relevance of the (AAT)n CNR1 repeats in the inflammatory neurodegenerative damage of MS

Rigidity of critical metrics of some quadratic curvature functionals

LAUREA MAGISTRALELe metriche canoniche su varietà Riemanniane sono metriche che presentano notevoli proprietà ed un alto grado di simmetria. Una naturale linea di ricerca in geometria Riemanniana è quella di dedurre le proprietà topologiche della varietà per mezzo di tali metriche canoniche. Un modo tipico di costruire tali oggetti è quello di studiare i punti critici di funzionali di curvatura. Inerentemente a ciò, la presente tesi investiga il caso di una metrica canonica emersa come punto critico di un funzionale di curvatura quadratico, vincolata a rispettare una condizione sulla sua curvatura sezionale. Questo ha portato sia ad estendere un risultato di G. Catino, che ad ottenerne uno originale. In particolare, abbiamo trovato che una metrica critica per il funzionale mathfrak{F}_{t} soddisfacente una condizione sulla curvatura della forma Sec > epsilon R, per un certo epsilon dipendente sia da t che dalla dimensione n della varietà, è una metrica di Einstein. Questo, in dimensione quattro, forza la varietà ad essere o mathbb{S}^{4}, o mathbb{CP}^{2} oppure mathbb{RP}^{4} con le rispettive metriche standard.Canonical metrics on Riemannian manifolds are metrics that exhibit remarkable properties and a high degree of symmetry. A natural quest in Riemannian geometry is to capture the topology of a manifold through means of such canonical metrics. A typical way of building such objects is to look for them between the critical points of a curvature functional. In this regard, the present thesis investigated the case of a canonical metric emerging as a critical point of a quadratic curvature functional, under a sectional curvature condition, both extending a previous result by G. Catino and providing a new one. We have found that a critical metric for the mathfrak{F}_{t} functional, satisfying a curvature pinching condition of the form Sec > epsilon R, for a proper epsilon depending both on t and the dimension n of the manifold, is an Einstein metric. This, in dimension-four, forces the manifold to be either mathbb{S}^{4}, mathbb{CP}^{2} or mathbb{RP}^{4} with their standard metrics

Oscillating nonlinear large scale structure in growing neutrino quintessence

Growing Neutrino quintessence describes a form of dynamical dark energy that could explain why dark energy dominates the universe only in recent cosmological times. This scenario predicts the formation of large scale neutrino lumps which could allow for observational tests. We perform for the first time N-body simulations of the nonlinear growth of structures for cold dark matter and neutrino fluids in the context of Growing Neutrino cosmologies. Our analysis shows a pulsation - increase and subsequent decrease - of the neutrino density contrast. This could lead to interesting observational signatures, as an enhanced bulk flow in a situation where the dark matter density contrast only differs very mildly from the standard LCDM scenario. We also determine for the first time the statistical distribution of neutrino lumps as a function of mass at different redshifts. Such determination provides an essential ingredient for a realistic estimate of the observational signatures of Growing Neutrino cosmologies. Due to a breakdown of the non-relativistic Newtonian approximation our results are limited to redshifts z > 1.Comment: 17 pages, 1 table, 10 figures; MNRAS in pres