564 research outputs found
Rules versus discretion in fiscal policy
This paper purports to apply the Kydland-Prescott framework of dynamic inconsistency to the case of fiscal policy, by considering the trade-off between output and debt stabilization. The Government budget constraint provides the link between debt dynamics and the level of activity, influenced by fiscal policy. Contrary to what happens in the monetary policy framework, however, a commitment is not always superior to discretion, even in the absence of uncertainty, but only when the public debt-GDP ratio is sufficiently large. The introduction of uncertainty, as usual, implies a reduction in the net benefit generated by the adoption of a fixed rule.rules, discretion, time inconsistency, fiscal policy
Use of Sperm Proteins as a Putative Fertility Marker
The objectives of this study were to characterize the variation and evaluate whether CD9 and SERPINA5 could be used as fertility markers in bovine sperm
A review on the formation of heteronuclear cold molecules
Is the characterization of biological systems as complex systems in the mathematical sense a fruitful assertion? In this paper we argue in the affirmative, although obviously we do not attempt to confront all the issues raised by this question. We use the fly's visual system as an example and analyse our experimental results of one particular neuron in the fly's visual system from this point of view. We find that the motion-sensitive ‘H1’ neuron, which converts incoming signals into a sequence of identical pulses or ‘spikes’, encodes the information contained in the stimulus into an alphabet composed of a few letters. This encoding occurs on multilayered sets, one of the features attributed to complex systems. The conversion of intervals between consecutive occurrences of spikes into an alphabet requires us to construct a generating partition. This entails a one-to-one correspondence between sequences of spike intervals and words written in the alphabet. The alphabet dynamics is multifractal both with and without stimulus, though the multifractality increases with the stimulus entropy. This is in sharp contrast to models generating independent spike intervals, such as models using Poisson statistics, whose dynamics is monofractal. We embed the support of the probability measure, which describes the distribution of words written in this alphabet, in a two-dimensional space, whose topology can be reproduced by an M-shaped map. This map has positive Lyapunov exponents, indicating a chaotic-like encoding.FAPESPCNP
Purification of a monoclonal antibody using a novel high-capacity multimodal cation exchange nonwoven membrane
A high-capacity, multimodal cation exchange (MMC) chromatographic membrane was developed by conjugating a multimodal ligand – 2-mercaptopyridine-3-carboxylic acid (MPCA) – on a polybutylene terepthalate (PBT) nonwoven fabric. The membrane features an equilibrium binding capacity of ≈ 1000 mg of human polyclonal IgG (IgG) per g of membrane and dynamic binding capacities (DBC10%) ranging from 77.5 to 115.1 mg/mL (residence times of 1 and 5 min, respectively); these values are 2-to-3-fold higher than those of commercial MMC adsorbents. The effects of buffer composition, pH, conductivity on the binding behavior of the MMC-MPCA membrane were investigated in detail. As a moderate cation exchange binder, MPCA enables effective protein elution using buffers with mild pH (8.0–9.0) and conductivity (≈13 mS/cm), thus circumventing the harsh conditions often needed in multimodal chromatography. The MMC-MPCA membrane was evaluated for product capture in bind-and-elute mode on a Chinese hamster ovary (CHO) cell culture harvest containing therapeutic monoclonal antibodies, using commercial multimodal (Capto MMC and MX-Trp-650M) and affinity (AF-rProtein A HC-650F) resins as controls. The MMC-MPCA membrane outperformed the multimodal resins in terms of binding capacity as well as clearance of host cell proteins (HCPs) and aggregates. The membrane was then evaluated by polishing the mAb from a Protein A eluate in bind-and-elute mode. The MMC-MPCA membrane reduced the level of high molecular weight components from 11% to 4% and the HCP content from 1319.7 ppm to 48.7 ppm (LRV of 1.4). Most notably, proteomics analysis of the product demonstrated the clearance of a significant fraction of persistent, high-risk HCPs from the Protein A eluate
value of mr venography for detection of internal jugular vein anomalies in multiple sclerosis a pilot longitudinal study
BACKGROUND AND PURPOSE: CCSVI was recently described in patients with MS. CCSVI is diagnosed noninvasively by Doppler sonography and invasively by catheter venography. We assessed the role of conventional MRV for the detection of IJV anomalies in patients with MS diagnosed with CCSVI and in healthy controls who underwent MRV and Doppler sonography examinations during 6 months. MATERIALS AND METHODS: Ten patients with MS underwent TOF, TRICKS, Doppler sonography, and catheter venography at baseline. They were treated at baseline with percutaneous angioplasty and re-evaluated 6 months9 posttreatment with MRV and Doppler sonography. In addition, 6 healthy controls underwent a baseline and a 6-month follow-up evaluation by Doppler sonography and MRV. RESULTS: At baseline, the sensitivity, specificity, PPV, and NPV of Doppler sonography for detecting IJV abnormalities relative to catheter venography in patients with MS were calculated, respectively, at 82%, 100%, 99%, and 95%. The figures were 99%, 33%, 33%, 99% for TOF and 99%, 39%, 35%, and 99% for TRICKS. Venous anomalies included the annulus, septum, membrane, and malformed valve. No agreement was found between TOF and catheter venography in 70% of patients with MS and between TRICKS and catheter venography in 60% of patients with MS. At follow-up, 50% of the patients with MS presented with abnormalities on Doppler sonography but only 30% were diagnosed with restenosis. CONCLUSIONS: Conventional MRV has limited value for assessing IJV anomalies for both diagnostic and posttreatment purposes
Use of Pregnancy Associated Glycoproteins to determine Fetal Age Throughout Gestation
The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations that would be indicative of stage of pregnancy or fetal age
Formation of ultracold RbCs molecules by photoassociation
The formation of ultracold metastable RbCs molecules is observed in a double
species magneto-optical trap through photoassociation below the
^85Rb(5S_1/2)+^133Cs(6P_3/2) dissociation limit followed by spontaneous
emission. The molecules are detected by resonance enhanced two-photon
ionization. Using accurate quantum chemistry calculations of the potential
energy curves and transition dipole moment, we interpret the observed
photoassociation process as occurring at short internuclear distance, in
contrast with most previous cold atom photoassociation studies. The vibrational
levels excited by photoassociation belong to the 5th 0^+ or the 4th 0^-
electronic states correlated to the Rb(5P_1/2,3/2)+Cs(6S_1/2) dissociation
limit. The computed vibrational distribution of the produced molecules shows
that they are stabilized in deeply bound vibrational states of the lowest
triplet state. We also predict that a noticeable fraction of molecules is
produced in the lowest level of the electronic ground state
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