113,503 research outputs found
Aspects of Neutrino Interactions (Scattering at small - Region)
The article begins with a description of chiral symmetry and its application
to neutrino induced reactions. For small (forward direction) the process
is dominated by the amplitute with helicity zero where the pion pole disappears
when multiplied with the polarization vector. The remaining part of the
amplitude is determined by PCAC. For GeV the computed cross
sections are in good agreement with data. In coherent pion production we expect
equal yields for neutrinos and antineutrinos a relation which for
GeV is fulfilled. We discuss specific features of the data and suggest methods
for improving them by presenting new estimates for the incoherent background.Comment: Presented at the CETUP-Workshop on Neutrino Interactions, July 22-31,
2014 at Lead/Dead Wood, South Dakota, USA. The resubmission contains minor
correction
Gamma-ray spectrometry in the field: Radioactive heat production in the Central Slovakian Volcanic Zone
We report 62 sets of measurements from central-southern Slovakia, obtained using a modern portable gamma-ray spectrometer, which reveal the radioactive heat production in intrusive and extrusive igneous rocks of the Late Cenozoic Central Slovakian Volcanic Zone. Sites in granodiorite of the Štiavnica pluton are thus shown to have heat production in the range ~ 2.2–4.9 μW m− 3, this variability being primarily a reflection of variations in content of the trace element uranium. Sites in dioritic parts of this pluton have a lower, but overlapping, range of values, ~ 2.1–4.4 μW m− 3. Sites that have been interpreted in adjoining minor dioritic intrusions of similar age have heat production in the range ~ 1.4–3.3 μW m− 3. The main Štiavnica pluton has zoned composition, with potassium and uranium content and radioactive heat production typically increasing inward from its margins, reflecting variations observed in other granodioritic plutons elsewhere. It is indeed possible that the adjoining dioritic rocks, hitherto assigned to other minor intrusions of similar age, located around the periphery of the Štiavnica pluton, in reality provide further evidence for zonation of the same pluton. The vicinity of this pluton is associated with surface heat flow ~ 40 mW m− 2 above the regional background. On the basis of our heat production measurements, we thus infer that the pluton has a substantial vertical extent, our preferred estimate for the scale depth for its downward decrease in radioactive heat production being ~ 8 km. Nonetheless, this pluton lacks any significant negative Bouguer gravity anomaly. We attribute this to the effect of the surrounding volcanic caldera, filled with relatively low-density lavas, ‘masking’ the pluton's own gravity anomaly. We envisage that emplacement occurred when the pluton was much hotter, and thus of lower density, than at present, its continued uplift, evident from the local geomorphology, being the isostatic consequence of localized erosion. The heat production in this intrusion evidently plays a significant role, hitherto unrecognized, in the regional geothermics
Comparing Heterogeneous Consumption in US and Japanese Meat and Fish Demand
This article uses national, quarterly data to conduct an empirical analysis of pre-committed meat and fish demand by US and Japanese households using the Generalized Almost Ideal Demand System (GAIDS). US consumers are found to hold pre-committed demand for beef and pork, while Japanese consumers appear to possess significant pre-committed demand for beef and fish. This provides evidence to partly explain observed differences in Japanese and US consumer reactions to non-price and non-income effects in beef, pork, poultry, and fish. In addition, the first known empirical comparison of how the GAIDS and more traditional AIDS models assess meat and fish demand is offered with both in- and out-of-sample evaluations.US/Japanese meat demand, demand forecasting, food safety, Generalized Almost Ideal Demand System, pre-committed consumption, Demand and Price Analysis,
Studies of low-energy ionic collisions Final report, 1 Oct. 1965 - 30 Sep. 1967
Ionic-molecular collisions, and collision induced dissociation of ion
A consistent spatial differencing scheme for the transonic full-potential equation in three dimensions
A full-potential steady transonic wing flow solver has been modified so that freestream density and residual are captured in regions of constant velocity. This numerically precise freestream consistency is obtained by slightly altering the differencing scheme without affecting the implicit solution algorithm. The changes chiefly affect the fifteen metrics per grid point, which are computed once and stored. With this new method, the outer boundary condition is captured accurately, and the smoothness of the solution is especially improved near regions of grid discontinuity
Spatial control of irreversible protein aggregation
Liquid cellular compartments spatially segregate from the cytoplasm and can
regulate aberrant protein aggregation, a process linked to several medical
conditions, including Alzheimer's and Parkinson's diseases. Yet the mechanisms
by which these droplet-like compartments affect protein aggregation remain
unknown. Here, we combine kinetic theory of protein aggregation and
liquid-liquid phase separation to study the spatial control of irreversible
protein aggregation in the presence of liquid compartments. We find that, even
for weak interactions between the compartment constituents and the aggregating
monomers, aggregates are strongly enriched inside the liquid compartment
relative to the surrounding cytoplasm. We show that this enrichment is caused
by a positive feedback mechanism of aggregate nucleation and growth which is
mediated by a flux maintaining the phase equilibrium between the compartment
and the cytoplasm. Our model predicts that the compartment volume that
maximizes aggregate enrichment in the compartment is determined by the reaction
orders of aggregate nucleation. The underlying mechanism of aggregate
enrichment could be used to confine cytotoxic protein aggregates inside
droplet-like compartments suggesting potential new avenues against aberrant
protein aggregation. Our findings could also represent a common mechanism for
the spatial control of irreversible chemical reactions in general
Did the Bundesbank React to Stock Price Movements?
In this paper, we investigate the relationship between stock returns and short-term interest rates. Identification of the stock return-interest rate relation is solved by using a new technique that relies on the heteroskedasticity of shocks to stock market returns. We suggest some improvements to the identification technique and its justification, as well as providing some new findings. In particular, we ask whether the Bundesbank, prior to the European Central Bank taking responsibility for monetary policy in 1999, reacted systematically to stock price movements. In contrast to the results for the US, our empirical findings for the 1985 - 1998 period show a positive, but statistically insignificant, parameter for the relationship between German stock returns and short-term interest rates at the daily frequency. The same result is found at the monthly frequency. Nevertheless, the confidence bands are wide enough that we cannot entirely exclude the possibility of a reaction at lower frequencies. The results are extremely robust to alternative methods used to identify changes in heteroskedasticity. The evidence is, therefore, inconsistent with the hypothesis of a systematic reaction of the Bundesbank to every wiggle in German stock prices. Both the historical and institutional evidence are supportive of this conclusion. -- In diesem Diskussionspapier untersuchen wir den Zusammenhang zwischen Aktienkursveränderungen und Veränderungen der kurzfristigen Zinssätze. Die ökonometrische Identifikation dieses Zusammenhangs erfolgt mit Hilfe eines neuen Verfahrens, das die Heteroskedastie von Aktienkursveränderungen ausnutzt. Wir schlagen einige Verbesserungen und Rechtfertigungen zu diesem Verfahren vor und liefern neue empirische Befunde. Im Vordergrund der Betrachtungen steht die Frage, ob die Bundesbank vor der Übernahme der geldpolitischen Entscheidungen durch die Europäische Zentralbank im Jahre 1999 systematisch auf Veränderungen der Aktienkurse reagiert hat. Im Unterschied zu den verfügbaren Ergebnissen für die Vereinigten Staaten von Amerika, finden wir auf Basis von Tagesdaten zwar einen positiven, aber statistisch nicht signifikanten Parameter für die Reaktion des kurzfristigen Zinssatzes auf Änderungen des Aktienkurses. Auf der Grundlage von Monatsdaten ist der Parameter ebenfalls positiv und statistisch insignifikant. Die Konfidenzintervalle sind aber sehr breit, so dass eine Reaktion auf der niedrigeren Frequenz nicht völlig ausgeschlossen werden kann. Die empirischen Resultate sind sehr robust gegenüber unterschiedlichen Modellspezifikationen. Die empirische Evidenz widerspricht somit der These einer systematischen Reaktion der Bundesbank auf jede Bewegung am Aktienmarkt, was durch die historischen und institutionellen Gegebenheiten gestützt wird.
Asset Prices in Taylor Rules: Specification, Estimation, and Policy Implications for the ECB
This paper estimates standard and extended Taylor rules for core countries in the euro area, namely France, Germany and Italy, as well as for the ECB. Forward, backward and forecast-based rules are estimated for a variety of samples since the late 1970s. We are particularly interested in the impact of adding asset prices to the standard Taylor rule specification. Since forward-looking Taylor rules are usually estimated via GMM we perform extensive tests for over-identifying restrictions and instrument relevance, a practice generally eschewed in previous work. We find that asset prices can be highly relevant as instruments rather than as separate arguments in policy rules. Backwardlooking Taylor rules, however, cannot be rejected outright. Forecast-based rules perform best using the root mean squared error metric but produce coefficients implying that central banks may be too aggressive at fighting inflation. Encompassing tests are therefore required to select the ?best? policy rule and these suggest that policy rules need to have a mix of forward and forecast-based elements. Furthermore too aggressive reactions to stock prices in particular would have led to an implausible monetary policy. Hence, asset prices appear at best to serve as indicators of the direction of interest rates and not as a variable that the ECB directly reacts to. --reaction function,asset prices
- …