1,166 research outputs found
On the viability of m**2 phi**2 and natural inflation
In the context of single field inflation, models with a quadratic potential
and models with a natural potential with subplanckian decay constant are in
tension with the Planck data. We show that, when embedded in a two-field model
with an additional super massive field, they can become consistent with
observations. Our results follow if the inflaton is the phase of a complex
field (or an angular variable) protected by a mildly broken U(1) symmetry, and
the radial component, whose mass is much greater than the Hubble scale, is
stabilized at subplanckian values. The presence of the super massive field,
besides modifying the effective single field potential, causes a reduction in
the speed of sound of the inflaton fluctuations, which drives the prediction
for the primordial spectrum towards the allowed experimental values. We discuss
these effects also for the linear potential, and show that this model increases
its agreement with data as wellComment: 14 pages, 7 figures. v2 added missing abstract in the pdf, references
and very minor changes. v3. typos corrected, references adde
Dimethyl fumarate: a new oral treatment option for multiple sclerosis
Multiple Sclerosis (MS) is a slowly progressive, immunologically mediated disease of the CNS. The recent years have witnessed great efforts in establishing new therapeutic options for multiple sclerosis. There is a clear need for more effective, safe and at the same time orally available treatment options. Here we review the recently approved drug Dimethyl fumarate (DMF, Tecfidera®) as a new therapeutic option for MS and its role in context to the existing oral treatment options for MS. Dimethyl fumarate is the methyl ester of fumaric acid and has been claimed to possess immunomodulatory properties and is already in clinical use as Fumaderm for severe systemic psoriasis. In addition, Dimethyl fumarate was also shown to act on the blood-brain barrier and exert neuroprotective properties via activation of anti-oxidative pathways and displayed beneficial effects in experimental autoimmune encephalomyelitis (EAE), a model mimicking many aspects of MS. Based on two global phase III studies. Dimethyl fumarate has been clinically proven to significantly reduce important measures of disease activity, including relapses and development of brain lesions, as well as to slow disability progression over time, while demonstrating a favourable safety and tolerability profile
Primordial black hole formation with non-Gaussian curvature perturbations
In the context of transient constant-roll inflation near a local maximum, we
derive the non-perturbative field redefinition that relates a Gaussian random
field with the true non-Gaussian curvature perturbation. Our analysis shows the
emergence of a new critical amplitude , corresponding to perturbations
that prevent the inflaton from overshooting the local maximum, thus becoming
trapped in the false minimum of the potential. For potentials with a mild
curvature at the local maximum (and thus small non-Gaussianity), we recover the
known perturbative field redefinition. We apply these results to the formation
of primordial black holes, and discuss the cases for which is smaller
or of the same order than the critical value for collapse of spherically
symmetric overdensities. In the latter case, we present a simple potential for
which the power spectrum needs an amplitude 10 times smaller that in the
Gaussian case for producing a sizeable amount of primordial black holes.Comment: 13 pages, 8 figures. v2: expanded explanations + small changes. v3:
small typos correcte
The two-field regime of natural inflation
The simplest two-field completion of natural inflation has a regime in which
both fields are active and in which its predictions are within the Planck
1- confidence contour. We show this for the original model of natural
inflation, in which inflation is achieved through the explicit breaking of a
U(1) symmetry. We consider the case in which the mass coming from explicit
breaking of this symmetry is comparable to that from spontaneous breaking,
which we show is consistent with a hierarchy between the corresponding energy
scales. While both masses are comparable when the observable modes left the
horizon, the mass hierarchy is restored in the last e-foldings of inflation,
rendering the predictions consistent with the isocurvature bounds. For
completeness, we also study the predictions for the case in which there is a
large hierarchy of masses and an initial period of inflation driven by the
(heavy) radial field.Comment: 18 pages, 9 figure
New Century, Old Disparities: Gender and Ethnic Wage Gaps in Latin America
This paper surveys gender and ethnic wage gaps in 18 Latin American countries, decomposing differences using matching comparisons as a non-parametric alternative to the Blinder-Oaxaca (BO) decomposition. It is found that men earn 9-27 percent more than women, with high cross-country heterogeneity. The unexplained pay gap is higher among older, informal and self-employed workers and those in small firms. Ethnic wage differences are greater than gender differences, and educational attainment differentials play an important role in explaining the gap. Higher ethnic wage gaps are found among males, single-income generators of households and full-time workers, and in rural areas. An important share of the ethnic wage gap is due to the scarcity of minorities in high-paid positions.gender, ethnicity, wage gaps, Latin America, matching
Cumulative effects in inflation with ultra-light entropy modes
In multi-field inflation one or more non-adiabatic modes may become light,
potentially inducing large levels of isocurvature perturbations in the cosmic
microwave background. If in addition these light modes are coupled to the
adiabatic mode, they influence its evolution on super horizon scales. Here we
consider the case in which a non-adiabatic mode becomes approximately massless
("ultralight") while still coupled to the adiabatic mode, a typical situation
that arises with pseudo-Nambu-Goldstone bosons or moduli. This ultralight mode
freezes on super-horizon scales and acts as a constant source for the curvature
perturbation, making it grow linearly in time and effectively suppressing the
isocurvature component. We identify a Stuckelberg-like emergent shift symmetry
that underlies this behavior. As inflation lasts for many e-folds, the
integrated effect of this source enhances the power spectrum of the adiabatic
mode, while keeping the non-adiabatic spectrum approximately untouched. In this
case, towards the end of inflation all the fluctuations, adiabatic and
non-adiabatic, are dominated by a single degree of freedom.Comment: 27 pages, 1 figure; v2: improved discussions, version published in
JCA
New Century, Old Disparities: Gender and Ethnic Wage Gaps in Latin America
This paper surveys gender and ethnic wage gaps in 18 Latin American countries, decomposing differences using matching comparisons as a non-parametric alternative to the Blinder-Oaxaca (BO) decomposition. It is found that men earn 9-27 percent more than women, with high cross-country heterogeneity. The unexplained pay gap is higher among older, informal and self-employed workers and those in small firms. Ethnic wage differences are greater than gender differences, and educational attainment differentials play an important role in explaining the gap. Higher ethnic wage gaps are found among males, singleincome generators of households and full-time workers, and in rural areas. An important share of the ethnic wage gap is due to the scarcity of minorities in highpaid positions.gender, ethnicity, wage gaps, Latin America, matching
The Big Mac Index And Real-Income Disparity
The Big Mac Index was introduced to (semi-humorously) test the theory of purchasing power parity and measure the disparity in currency values. Instead, in this paper, we consider this index to find out the per capita real-income disparity across 54 countries. We find that the per capita real-income can be very low in some countries even when Big Mac burgers are very cheap, like in India. Among these countries, Hong Kong’s per capita Big Mac affordability is the highest with 47 burgers daily whereas Pakistan’s people could afford just one a day. Additionally, we find that Russia and China’s Big Mac affordability has been significantly increasing over the last decade, Brazil’s has remained more or less constant, however USA’s Big Mac affordability has been falling, indicating that per capita real-income of Americans has been decreasing over the last decade. Finally, we find that increased role of the government might be negatively correlated to per capita real-income. Czech Republic has been experiencing increased Big Mac affordability as the country has been reducing the government’s role; whereas Argentina has been experiencing reduced Big Mac affordability as the country has been moving left and increasing the government’s power
COST ANALYSIS OF COMMONLY USED DRUGS UNDER PRICE CONTROL IN INDIA: ASSESSING THE EFFECT OF DRUG PRICE CONTROL ORDER ON BRAND PRICE VARIATION
Objective:Â Rising cost of medical therapy is a major concern for patients, and there is high variability in the prices of numerous branded medicines available in India. Drug Price Control Order (DPCO) 2013 was implemented by the government of India with the aim of bringing down the cost of essential medicines. This cost analysis study was carried out to assess the brand price variation in major classes of common drugs under price control; thus assessing the impact of DPCO and analyse issues related to it.Methods: Latest price list of available brands for cardiovascular drugs, antibacterial, analgesics, drugs for diabetes, asthma, arthritis, convulsions covered under the DPCO, was procured from a leading commercial drug directory. Unit prices of drug formulations available as different brands were compared. Maximum-minimum prices and average prices were found. Price variations between brands were calculated and expressed as percentage variations. Assessment of existing pricing policy and quality norms was done.Results: Significant inter-brand price variations were found for the majority of formulations. These variations ranged from more than 100 % from average to more than 500 % between maximum and minimum brand prices for drugs like amlodipine, atorvastatin, diclofenac, amoxicillin-clavulanic acid, clopidogrel. Out of 60 formulations observed, 40 showed price variations in excess of 50 % from average price and 23 showed variations greater than 200 % between the costliest and cheapest brands.Conclusion: Despite the implementation of price control, brand price variations still exist widely for commonly used drugs. Re-assessment of pricing policy and implementation of quality norms is needed.Keywords: Pharmacoeconomics, Price control, Brands, Price variation, Essential medicine
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