8,733 research outputs found
Unlearned Lessons from Risk, Debt Service, Bank Credit, and Asymmetric Information
This paper presents a model of the economy that explains the economic bubbles, based on bank credit, debt service and risk. In the first period of the model, banks offer too much credit seeking to maximise their expected profits. The excessive debt created in the boom period generates, in the second-period, the expansion of the debt bubble, which induces failures in the financial market and the downturn of the overall economy. Business cycles are inherent in the free market systems. They may be caused by endogenous factors of financial markets and, given the absence of adequate, effective regulation, they may be unavoidable. Credit crunch in the financial market is therefore highly probable. In order to reduce substantially the risk of such occurrences, economic and financial policies are proposed. Key words: Asymmetric information, bank credit, risk, debt service and business cycle
Transient Nucleation near the Mean-Field Spinodal
Nucleation is considered near the pseudospinodal in a one-dimensional
model with a non-conserved order parameter and long-range
interactions. For a sufficiently large system or a system with slow relaxation
to metastable equilibrium, there is a non-negligible probability of nucleation
occurring before reaching metastable equilibrium. This process is referred to
as transient nucleation. The critical droplet is defined to be the
configuration of maximum likelihood that is dynamically balanced between the
metastable and stable wells. Time-dependent droplet profiles and nucleation
rates are derived, and theoretical results are compared to computer simulation.
The analysis reveals a distribution of nucleation times with a distinct peak
characteristic of a nonstationary nucleation rate. Under the quench conditions
employed, transient critical droplets are more compact than the droplets found
in metastable equilibrium simulations and theoretical predictions.Comment: 7 Pages, 5 Figure
Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements
Measurements of coherent radiation at accelerators typically give the
absolute value of the beam profile Fourier transform but not its phase. Phase
reconstruction techniques such as Hilbert transform or Kramers Kronig
reconstruction are used to recover such phase. We report a study of the
performances of these methods and how to optimize the reconstructed profiles.Comment: Presented at IPAC'14 - THPME08
Global aspects of gravitomagnetism
We consider global properties of gravitomagnetism by investigating the
gravitomagnetic field of a rotating cosmic string. We show that although the
gravitomagnetic field produced by such a configuration of matter vanishes
locally, it can be detected globally. In this context we discuss the
gravitational analogue of the Aharonov-Bohm effect.Comment: 10 pages - Typeset using REVTE
Puntos cuĂĄnticos: nueva aportaciĂłn de la nanotecnologĂa en investigaciĂłn y medicina
Los Puntos CuĂĄntico (PCs) son nanocristales mĂĄs fotoestables, monocromĂĄticos y brillantes que cualquier fluorocromo. Estas cualidades y su capacidad de formar mĂșltiples constructos (funcionalizaciĂłn con anticuerpos, oligonucleĂłtidos, Biotina, lectinas, iones magnĂ©ticos, etc.) les otorgan una enorme versatilidad analĂtica y una sensibilidad a nivel de molĂ©cula Ășnica. AdemĂĄs de mejorar determinaciones estĂĄndar como el PSA, los PCs ofrecen nuevas alternativas en Western blotting y citometrĂa de flujo. La manufacturaciĂłn de âlaboratorios en un chipâ es uno de los productos nanotecnolĂłgicos mĂĄs destacados ya que permiten mĂșltiples anĂĄlisis simultĂĄneos, a tiempo real, con un coste reducido y cantidades Ănfimas de muestra. En el campo de la biotecnologĂa los PCs son Ăștiles en la identificaciĂłn gĂ©nica por cĂłdigo de barras multicolor en microchips. Los PCs unidos a ACs especĂficos permiten la detecciĂłn por fluorescencia de diversas dianas en rutas metabĂłlicas intracitoplasmĂĄticas de cĂ©lulas vivas sin alterar su fisiologĂa. MĂĄs aĂșn, permiten comprender, a la vez, el trĂĄfico de proteĂnas, su localizaciĂłn, reciclaje y funciĂłn en lo que se viene llamando ProteĂłmica Visual. Nuevas aplicaciones en oncologĂa clĂnica permiten identificar cĂ©lulas cancerosas aisladas en sangre circulante y una mayor exactitud en el mapeado de Glanglio centinela en neoplasias de mama, asĂ como conseguir discriminar selectivamente el nĂłdulo tumoral en neurocirugĂa cerebral. ÂżEstamos a las puertas del diagnĂłstico y terapia secuenciales por PCs en el mismo acto mĂ©dico; biopsia Ăłptica?. La medicina regenerativa promete terapias sustitutivas de Ăłrganos y tejidos generados âin vitroâ. Los nanotubos de carbono actĂșan mejorando los sustratos para el crecimiento celular diferenciado de cĂ©lulas madre. AdemĂĄs, son Ăștiles para la liberaciĂłn controlada de medicinas, en particular citoestĂĄticos unidos a ACs oncoespecĂficos, y como vehĂculo de vectores genĂ©ticos. La NanotecnologĂa y los Puntos QuĂĄnticos en particular representan el futuro del diagnĂłstico del laboratorio, la biologĂa celular y la terapia oncolĂłgica.Quantum Dots (QDs) are more fotostable, monochromatic and brilliant than any standard fluorocrome. These qualities and their capacity to build different constructors (targeted with antibodies, oligonucleotides, Biotine, lectines, magnetic ions, etc) allow them a wide versatility and sensibility, even to single molecular levels. Furthermore, improving standard PSA and other tests QDs represent a new alternative in Western blotting and flow citometry. Laboratories-on-a-chip, one of the more original nanoproducts, makes possible a wide variety of clinical tests simultaneously at real time, low cost and a minimal amount of sample. QDs are also being employed in biotechnology to genetic identifications through multicolour barcodes on microchips. QDs nanocrystalâlabeled antibodies allow simultaneous and safe detection of multiple molecules in metabolic tracts inside living cells. Even traffic, localization, turnover and function of proteins can be understood at a time, giving birth to Visual Proteomics. New implementations in clinical oncology enable cancer cells recognition in circulating blood, more precise identification of the sentinel node in breast neoplasia as well as selectively delimitate malignant growths in brain surgery. Are we close to a sequential diagnosis and therapy in a single medical act by Quantum Dots; the optical biopsy? Regenerative medicine promises replacement therapy of organs and tissues growth âin vitroâ. Carbon Nanotubes improve the substratum to steam cells differentiation as well as under control drugs release, particularly targeted citostatics or genetic vectors. Nanotechnology and particularly Quantum Dots represent the future tools for laboratory diagnosis, cell biology and cancer therapy
Relevance or irrelevance of capital structure?
In this paper we examine the effects of asymmetric information on the nature of financial equilibrium and on the capital structure of firms. In the first model presented, the financial contracts on offer involve pooling equilibrium with no adverse selection. However, in the special case analyzed, where contracts are of mixed form, there may be a separating equilibrium and also equilibrium may not exist. Interesting result is that the separating equilibrium found is not economically efficient since aggregate investments falls short of first-best level. More importantly, capital structure does matter. The relative magnitude of outside equity makes a real difference to the quantity of aggregate investment in equilibrium
Clival chordomas: The endoscopic transnasal transsphenoidal approach
Os cordomas da base do crĂąnio sĂŁo tumores raros, localmente destrutivos, que constituem um desafio cirĂșrgico pela proximidade a estruturas neurovasculares vitais e ao elevado potencial de recidiva.
Os autores descrevem o caso de uma mulher de 45 anos, com quadro de cefaleias, anisocória e diplopia, com cinco meses de evolução, cujos exames complementares de diagnóstico revelaram uma volumosa lesão expansiva dos 2/3 superiores do clivus, com preenchimento do seio esfenoidal, destruição
selar e extensĂŁo para ambos os seios cavernosos. Procedeu-se a excisĂŁo da lesĂŁo, apĂłs biopsia diagnĂłstica compatĂvel com cordoma, por abordagem endoscĂłpica endonasal transesfenoidal (EET), guiada por neuronavegação. Com 3 meses de seguimento, a doente encontra-se clinicamente bem e a ressonĂąncia magnĂ©tica revela eventual resĂduo tumoral no seio cavernoso direito. A cirurgia EET constitui uma alternativa minimamente invasiva na abordagem de lesĂ”es expansivas da base do crĂąnio, possibilitando, em casos seleccionados, resultados similares e com menor morbilidade, relativamente Ă s tĂ©cnicas cirĂșrgicas clĂĄssicas.info:eu-repo/semantics/publishedVersio
The GREATS H+[OIII] Luminosity Function and Galaxy Properties at : Walking the Way of JWST
The James Webb Space Telescope will allow to spectroscopically study an
unprecedented number of galaxies deep into the reionization era, notably by
detecting [OIII] and H nebular emission lines. To efficiently prepare
such observations, we photometrically select a large sample of galaxies at
and study their rest-frame optical emission lines. Combining data from
the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS) survey and
from HST, we perform spectral energy distribution (SED) fitting, using
synthetic SEDs from a large grid of photoionization models. The deep
Spitzer/IRAC data combined with our models exploring a large parameter space
enables to constrain the [OIII]+H fluxes and equivalent widths for our
sample, as well as the average physical properties of galaxies, such
as the ionizing photon production efficiency with
. We
find a relatively tight correlation between the [OIII]+H and UV
luminosity, which we use to derive for the first time the [OIII]+H
luminosity function (LF) at . The [OIII]+H LF is higher
at all luminosities compared to lower redshift, as opposed to the UV LF, due to
an increase of the [OIII]+H luminosity at a given UV luminosity from
to . Finally, using the [OIII]+H LF, we make
predictions for JWST/NIRSpec number counts of galaxies. We find that
the current wide-area extragalactic legacy fields are too shallow to use JWST
at maximal efficiency for spectroscopy even at 1hr depth and JWST
pre-imaging to mag will be required.Comment: 13 pages, 9 figures, accepted for publication in MNRA
Influence of the concrete mechanical properties on the efficacy of the shear strengthening intervention on RC beams by NSM technique
The occurrence of a failure mode, different from debonding, consisting on the detachment, from the beam core,
of âtwo concrete lateral wallsâ containing the glued laminates, highlights the paramount importance of concrete
mechanical properties on the effectiveness of NSM shear strengthening technique. A new mechanical-analytical
interpretation of the phenomenon affecting the ultimate behaviour of RC beams NSM-strengthened in shear is
presented along with the main findings. This approach takes into account the possibility that the shear
strengthening contribution of the NSM laminates can be limited by the three following failure modes: debonding,
concrete tensile fracture and laminatesâ tensile rupture. The interaction between laminates can be also accounted
for. The proposed mechanical interpretation of the NSM laminates behaviour can be extended to NSM rods.Fundação para a CiĂȘncia e a Tecnologia (FCT) -
programa âCUTINSHEAR - Performance assessment of an innovative structural FRP strengthening technique
using an integrated system based on optical fiber sensorsâ s, POCTI/ECM/59033/2004. This
work has been partially carried out under the program âDipartimento di Protezione Civile â Consorzio RELUISâ,
signed on 2005-07-11 (n. 540), Research Line 8, whose financial support is greatly appreciatePrograma âDipartimento di Protezione Civile â Consorzio RELUISâ nÂș 540Research Line 8Empreiteiros CasaisS&PÂźSecil (UnibetĂŁo, Braga)Degussa
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