Estimando evapotranspiración en Puerto Rico

The United Nations Food and Agriculture Organization (FAO) has recommended the Penman-Monteith method as the single method for estimating reference evapotranspiration throughout the world. A disadvantage of the method, however, is its relatively high data requirement. Measurements of wind speed, humidity (or dew point temperature) and radiation tend to be the least available of the required parameters; therefore, the FAO has presented estimation procedures for these parameters. The purpose of this study was to evaluate estimation procedures for climate data to be used in the Penman-Monteith method for estimating long-term daily reference evapotranspiration, and to verify the accuracy of the procedures at four locations in Puerto Rico. Comparison of reference evapotranspiration determined by using the estimated and measured climate data shows reasonably good agreement. The methods presented in this paper are potentially valuable for calculating the long-term average daily reference evapotranspiration at any location in Puerto Rico. An example is provided to illustrate the use of the proposed estimation procedures for climate parameters. This study presents a comparison of reference evapotranspiration calculated by the Penman-Monteith method, with estimates previously made by using the Hargreaves-Samani method, for thirty-four locations in Puerto Rico. In addition, estimated peak evapotranspiration from the Soil Conservation Service (SCS) (now Natural Resources Conservation Service) Irrigation Guide for the Caribbean Area, the SCS Blaney-Criddle method and the Penman-Monteith method were compared for six vegetable crops at three locations in Puerto Rico. The results suggest that some irrigation systems may have been under-designed in terms of flow capacity in Puerto Rico.La Organización de Alimentos y Agricultura de las Naciones Unidas (FAO, por sus siglas en inglés) ha recomendado el método de Penman-Monteith como el único método de calculación que se debería usar para estimar evapotranspiración de referencia a través del mundo. Sin embargo, una desventaja del método es que requiere un número alto de datos. Las medidas de la velocidad del viento, la humedad (o la temperatura de punto de rocío) y la radiación tienden a ser los parámetros requeridos más difíciles de obtener; por ello, la FAO ofrece procedimientos alternos de estimación para estos parámetros. El propósito de este estudio fue evaluar los procedimientos de estimación de los datos del clima requeridos por el método de Penman-Monteith para estimar (a evapotranspiración de referencia promedio diaria a largo plazo y verificar la exactitud de los procedimientos en cuatro zonas de Puerto Rico. Se encontró una alta correlación entre la evapotranspiración de referencia calculada con los datos estimados (FAO) y la calculada con los datos observados del clima. Los métodos presentados son potenciatmente valiosos para calcular la evapotranspiración de referencia promedio diaria en cualquier zona de Puerto Rico. Se provee un ejemplo para ilustrar el uso del procedimiento propuesto para estimar parámetros del clima. Se presenta una comparación de la evapotranspiración de referencia calculada por el método de Penman-Monteith y resultados estimados previamente por el método de Hargreaves-Samani para 34 zonas en Puerto Rico. Además, el estimado máximo de evapotranspiración de la Guía de Riego del Servicio de Conservación de Suelos (SCS) (ahora Servicio de Conservación de Recursos Naturales) para el Área def Caribe, el método de Blaney-Criddfe (SCS) y él método de Penman-Monteith se compararon para seis vegetales en tres localidades en Puerto Rico. Los resultados indican que algunos sistemas de riego no tienen suficiente capacidad para suplir agua en Puerto Rico

Bioreduction of Solid Rocket Motors for Planetary Protection

Solid rocket propulsion systems have been used for in-space applications including planetary exploration missions for many years. Current NASA science lander projects require solid rocket propulsion systems to touchdown on the surface of potentially life-supporting planets and moons. A critical requirement of these missions is the prevention of accidental transportation of Earth's microbes to these environments. This mission requirement places an increased importance on the ability to reduce the biological burden that may be on board the solid propulsion systems and potentially deposited in a habitable environment. Some traditional interplanetary spacecraft decontamination operations could reduce the reliability of the solid propulsion system, indicating a need for new decontamination procedures. New techniques for biological burden reduction are being studied and may become the method of choice to ensure adequate reduction has been achieved. These techniques include biocidal elimination through chemical agents already present within the motor and cellular disruption due to assembly and operational environments induced in the motor. Recent investigations into the effectiveness of these techniques have generated promising experimental results. These techniques and current experimental results will be presented

Forward Guidance and Macroeconomic Outcomes since the Financial Crisis

This paper studies the effects of FOMC forward guidance. We begin by using high frequency identification and direct measures of FOMC private information to show that puzzling responses of private sector forecasts to movements in federal funds futures rates on FOMC announcement days can be attributed entirely to Delphic forward guidance. However a large fraction of futures rates' variability on announcement days remains unexplained, leaving open the possibility that the FOMC has successfully communicated Odyssean guidance. We then examine whether the FOMC used Odyssean guidance to improve macroeconomic outcomes since the financial crisis. To this end we use an estimated medium-scale New Keynesian model to perform a counterfactual experiment for the period 2009q1{2014q4, in which we assume the FOMC did not employ any Odyssean guidance and instead followed its reaction function from before the crisis as closely as possible while respecting the effective lower bound. We find that a purely rule-based policy would have delivered a shallower recession and kept inflation closer to target in the years immediately following the crisis than FOMC forward guidance did in practice. However starting toward the end of 2011, after the Fed's introduction of "calendar-based" communications, the FOMC's Odyssean guidance appears to have boosted real activity and moved inflation closer to target. We show that our results do not reflect Del Negro, Giannoni, and Patterson (2015)'s forward guidance puzzle

Multiphoton radiative recombination of electron assisted by laser field

In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons represents an equidistant pattern with the spacing equal to the laser frequency. The distribution of intensities in this spectrum is studied employing the Keldysh-type approximation, i.e. neglecting interaction of the impact electron with the atomic core in the initial continuum state. Within the adiabatic approximation the scale of emitted photon frequencies is subdivided into classically allowed and classically forbidden domains. The highest intensities correspond to emission frequencies close to the edges of classically allowed domain. The total cross section of electron recombination summed over all emitted photon channels exhibits negligible dependence on the laser field intensity.Comment: 14 pages, 5 figures (Figs.2-5 have "a" and "b" parts), Phys.Rev.A accepted for publication. Fig.2b is presented correctl

Técnica de avaliação da habilidade combinatória para a seleção eficiente de genitores de híbridos de arroz.

O uso dessa técnica levará a uma maior eficiência dos programas de criação de variedades híbridas e diminuirá globalmente os custos da pesquisa, reduzindo drasticamente o número de combinações híbridas a serem avaliadas. Adicionalmente, o ganho genético para habilidade combinatória em cada população, R ou B, será elevado e constante, garantindo a sustentabilidade do programa

Comparative biology of two populations of Lutzomyia umbratilis (Diptera: Psychodidae) of Central Amazonia, Brazil, under laboratory conditions.

Lutzomyia umbratilis is the main vector of cutaneous leishmaniasis due to Leishmania guyanensis in northern South America. It has been found naturally infected with this species of Leishmania only east of the Rio Negro and north of the Rio Amazonas. However, populations of this sand fly species are also present in areas south of the Amazon river system, which may act as a geographical barrier to the Leishmania guyanensis cycle. With the aim of looking for possible biological differences between populations of L. umbratilis from each side of this river system, their biology in the laboratory was investigated. Progenitors collected on tree bases in Manaus and Manacapuru (east and west, respectively, of the Rio Negro) were reared in the laboratory. Results from observations of the life cycle, fecundity, fertility, and adult longevity at 27 degrees C and 92% RH were analyzed by descriptive statistics and z, t, U, and chi2 tests. Although the Manaus and Manacapuru colonies showed a longer developmental time than most Lutzomyia species reared at similar temperatures, length of time of egg and 4th instar larva of the two populations differed significantly (p < 0.01). Females of the latter retained significantly (p < 0.001) less mature oocytes, and the general productivity (% adults from a known number of eggs) of the colony was significantly (p < 0.01) higher than that of the former. These results show that the L. umbratilis population of Manaus is more productive, and thus a better candidate for future mass-rearing attempts. The two populations differ in their life cycle, fecundity, fertility, adult longevity, and emergence. These differences may reflect some divergence of intrinsic biological features evolved as a result of their geographical isolation by the Rio Negro. It is expected that further investigations on morphometry, cuticular hydrocarbon, isoenzyme, molecular and chromossomal analyses, infection, and cross-mating experiments with these and other allopatric populations of both margins of the Amazon river system will help reveal whether or not L. umbratilis has genetically diverged into two or more reproductively isolated populations of vectors or non-vectors of Leishmania guyanensis

PloS one

The vasculoprotective properties of delphinidin are driven mainly by its action on endothelial cells. Moreover, delphinidin displays anti-angiogenic properties in both in vitro and in vivo angiogenesis models and thereby might prevent the development of tumors associated with excessive vascularization. This study was aimed to test the effect of delphinidin on melanoma-induced tumor growth with emphasis on its molecular mechanism on endothelial cells. Delphinidin treatment significantly decreased in vivo tumor growth induced by B16-F10 melanoma cell xenograft in mice. In vitro, delphinidin was not able to inhibit VEGFR2-mediated B16-F10 melanoma cell proliferation but it specifically reduced basal and VEGFR2-mediated endothelial cell proliferation. The anti-proliferative effect of delphinidin was reversed either by the MEK1/2 MAP kinase inhibitor, U-0126, or the PI3K inhibitor, LY-294002. VEGF-induced proliferation was reduced either by U-0126 or LY-294002. Under these conditions, delphinidin failed to decrease further endothelial cell proliferation. Delphinidin prevented VEGF-induced phosphorylation of ERK1/2 and p38 MAPK and decreased the expression of the transcription factors, CREB and ATF1. Finally, delphinidin was more potent in inhibiting in vitro cyclic nucleotide phosphodiesterases (PDEs), PDE1 and PDE2, compared to PDE3-PDE5. Altogether delphinidin reduced tumor growth of melanoma cell in vivo by acting specifically on endothelial cell proliferation. The mechanism implies an association between inhibition of VEGF-induced proliferation via VEGFR2 signalling, MAPK, PI3K and at transcription level on CREB/ATF1 factors, and the inhibition of PDE2. In conjunction with our previous studies, we demonstrate that delphinidin is a promising compound to prevent pathologies associated with generation of vascular network in tumorigenesis