1,528 research outputs found
A Fiscal Stimulus and Jobless Recovery
We analyse the effects of a government spending expansion in a dynamic stochastic general equilibrium (DSGE) model with Mortensen-Pissarides labour market frictions, deep habits and a constant-elasticity-of-substitution (CES) production function. The combination of deep habits and CES technology is crucial. The presence of deep habits enables the model to deliver output and unemployment multipliers in the high range of recent empirical estimates, while an elasticity of substitution between capital and labour in the range of available estimates allows it to produce a scenario compatible with the observed jobless recovery. An accommodative monetary policy with respect to the output gap alongside sticky prices plays an important role for the stabilisation properties of the fiscal stimulus.Fiscal policy; deep habits; labour market search-match frictions; unemployment; CES production function
Regularized Evolutionary Algorithm for Dynamic Neural Topology Search
Designing neural networks for object recognition requires considerable
architecture engineering. As a remedy, neuro-evolutionary network architecture
search, which automatically searches for optimal network architectures using
evolutionary algorithms, has recently become very popular. Although very
effective, evolutionary algorithms rely heavily on having a large population of
individuals (i.e., network architectures) and is therefore memory expensive. In
this work, we propose a Regularized Evolutionary Algorithm with low memory
footprint to evolve a dynamic image classifier. In details, we introduce novel
custom operators that regularize the evolutionary process of a micro-population
of 10 individuals. We conduct experiments on three different digits datasets
(MNIST, USPS, SVHN) and show that our evolutionary method obtains competitive
results with the current state-of-the-art
A Fiscal Stimulus with Deep Habits and Optimal Monetary Policy
A New-Keynesian model with deep habits and optimal monetary policy delivers a fiscal multiplier above one and the crowding-in effect on private consumption obtainable in a Real Business Cycle model à la Ravn et al. (2006). Optimized Taylor-type or price-level interest rate rules yield results close to optimal policy and dominate a conventional Taylor interest rate rule. Private consumption is crowded out only if the Taylor rule is sub-optimal and then negates the fiscal stimulus by responding strongly to the output gap, or if the ability to commit is absent. At the zero lower bound private consumption is always crowded in across simple rules.Deep habits, Optimal monetary policy, Price-level rule, Zero lower bound
Functional anatomy of 5-HT2A receptors in the amygdala and hippocampal complex : relevance to memory functions
The amygdaloid complex and hippocampal region contribute to emotional activities, learning, and memory. Mounting evidence suggests a primary role for serotonin (5-HT) in the physiological basis of memory and its pathogenesis by modulating directly the activity of these two areas and their cross-talk. Indeed, both the amygdala and the hippocampus receive remarkably dense serotoninergic inputs from the dorsal and median raphe nuclei. Anatomical, behavioral and electrophysiological evidence indicates the 5-HT2A receptor as one of the principal postsynaptic targets mediating 5-HT effects. In fact, the 5-HT2A receptor is the most abundant 5-HT receptor expressed in these brain structures and is expressed on both amygdalar and hippocampal pyramidal glutamatergic neurons as well as on γ-aminobutyric acid (GABA)-containing interneurons. 5-HT2A receptors on GABAergic interneurons stimulate GABA release, and thereby have an important role in regulating network activity and neural oscillations in the amygdala and hippocampal region. This review will focus on the distribution and physiological functions of the 5-HT2A receptor in the amygdala and hippocampal region. Taken together the results discussed here suggest that 5-HT2A receptor may be a potential therapeutic target for those disorders related to hippocampal and amygdala dysfunction.peer-reviewe
P-V-T Behavior of 2,3,3,3-Tetrafluoroprop-1-ene (HFO-1234yf) in the Vapor Phase from (243 to 373) K
The P-V-T properties of 2,3,3,3-tetrafluoroprop-1-ene (CF 3 CFdCH 2 , HFO-1234yf), an environmentally
friendly refrigerant, were measured using a constant volume apparatus. Measurements were carried out at
temperatures from (243 to 373) K and at pressures from (84 to 3716) kPa. A total of 136 experimental
points, taken along 12 isochores, were obtained. Our experimental results were compared with a preliminary
equation of state. The measurements were also regressed to the Martin-Hou equation of state. No other
data on this fluid were found in the literature for the superheated region
Daily rhythm of salivary and serum urea concentration in sheep
BACKGROUND: In domestic animals many biochemical and physiological processes exhibit daily rhythmicity. The aim of the present study was to investigate the rhythmic pattern of salivary and serum urea concentrations in sheep. METHODS: Six 3-year-old female sheep kept in the same environmental conditions were used. Sheep were sampled at 4 hour intervals for 48 consecutive hours starting at 08:00 of the first day and finishing at 04:00 of the second day. Blood samples were collected via intravenous cannulae inserted into the jugular vein; saliva samples were collected through a specific tube, the "Salivette". Salivary and serum urea concentrations were assayed by means of UV spectrophotometer. ANOVA was used to determine significant differences. The single Cosinor procedure was applied to the results showing significant differences over time. RESULTS: ANOVA showed a significant effect of time on salivary and serum urea concentrations. Serum and salivary urea peaked during the light phase. In the dark phase serum and salivary urea concentrations decreased, and the diurnal trough occurred at midnight. Cosinor analysis showed diurnal acrophases for salivary and serum urea concentrations. Daily mean levels were significantly higher in the serum than in the saliva. CONCLUSION: In sheep both salivary and serum urea concentrations showed daily fluctuations. Urea is synthesized in the liver and its production is strongly influenced by food intake. Future investigation should clarify whether daily urea rhythms in sheep are endogenous or are simply the result of the temporal administration of food
Probing the large-scale homogeneity of the universe with galaxy redshift surveys
Modern cosmological observations clearly reveal that the universe contains a hierarchy of clustering. However, recent surveys show a transition to homogeneity on large scales. The exact scale at which this transition occurs is still a topic of much debate. There has been much work done in trying to characterise the galaxy distribution using multifractals. However, for a number of years the size, depth and accuracy of galaxy surveys was regarded as insufficient to give a definitive answer. One of the main problems which arises in a multifractal analysis is how to deal with observational selection effects: i.e. 'masks' in the survey region and a geometric boundary to the survey itself. In this thesis I will introduce a volume boundary correction which is rather similar to the approach developed by Pan and Coles in 2001, but which improves on their angular boundary correction in two important respects: firstly, our volume correction 'throws away' fewer galaxies close the boundary of a given data set and secondly it is computationally more efficient. After application of our volume correction, I will then show how the underlying generalised dimensions of a given point set can be computed. I will apply this procedure to calculate the generalised fractal dimensions of both simulated fractal point sets and mock galaxy surveys which mimic the properties of the recent IRAS PSCz catalogue
Developmental changes of GABA immunoreactivity in cortico-thalamic networks of an absence seizure model
Absence seizures (ASs) are associated with abnormalities in gamma-aminobutyric acid (GABA) neurotransmission in the thalamus and the cortex. In the present study, we used light microscopy GABA immunocytochemistry to quantify the GABA-immunoreactive (GABA-IR) neurons and neuropil in the thalamic ventral basal (VB) nucleus, the nucleus reticularis thalami (NRT), the dorsal lateral geniculate (dLGN), the primary motor cortex (M1) and perioral region of the somatosensory cortex (S1po) of genetic absence epilepsy rats from Strasbourg (GAERS). We used both the relative non-epileptic control (NEC) and normal Wistar rats as control strains, and investigated GABA immunostaining at postnatal day 15 (P15), P25, and P90. The main findings were i) an increase in GABA-IR neuropil in the VB at P25 and P90 in GAERS but not in NEC and Wistar rats; ii) an increase in NRT GABA-IR neurons in GAERS and NEC, but not Wistar, rats at both P25 and P90; and iii) an increase in GABA-IR neuron density in S1po of GAERS at P25 and P90 and in Wistar at P90. These results indicate that the increased GABAergic innervation in the VB at P25 most likely contributes to the enhanced tonic inhibition observed in GAERS prior to AS onset, whereas the lack of any anatomo-morphological GABAergic differences in GAERS S1po suggests that functional more than structural abnormalities underlie the origin of cortical paroxysms in S1po of this AS model
- …