Quantitative Comparison of the Variability in Observed and Simulated Shortwave Reflectance

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is a climate observation system that has been designed to monitor the Earth's climate with unprecedented absolute radiometric accuracy and SI traceability. Climate Observation System Simulation Experiments (OSSEs) have been generated to simulate CLARREO hyperspectral shortwave imager measurements to help define the measurement characteristics needed for CLARREO to achieve its objectives. To evaluate how well the OSSE-simulated reflectance spectra reproduce the Earth s climate variability at the beginning of the 21st century, we compared the variability of the OSSE reflectance spectra to that of the reflectance spectra measured by the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY). Principal component analysis (PCA) is a multivariate decomposition technique used to represent and study the variability of hyperspectral radiation measurements. Using PCA, between 99.7%and 99.9%of the total variance the OSSE and SCIAMACHY data sets can be explained by subspaces defined by six principal components (PCs). To quantify how much information is shared between the simulated and observed data sets, we spectrally decomposed the intersection of the two data set subspaces. The results from four cases in 2004 showed that the two data sets share eight (January and October) and seven (April and July) dimensions, which correspond to about 99.9% of the total SCIAMACHY variance for each month. The spectral nature of these shared spaces, understood by examining the transformed eigenvectors calculated from the subspace intersections, exhibit similar physical characteristics to the original PCs calculated from each data set, such as water vapor absorption, vegetation reflectance, and cloud reflectance

Power line electrocution as an overlooked threat to Lear's Macaw (Anodorhynchus leari)

Electrocution can pose a serious threat to large birds, particularly threatened species with low population sizes. However, few studies have focused on the impacts of electrocution on large parrots such as the Endangered Lear's Macaw Anodorhynchus leari, endemic to the Brazilian Caatinga. Here, we compile and describe 31 electrocution events, as reported by villagers, indicating that electrocution may be an important threat to Lear's Macaw. We suggest a research and monitoring agenda to better understand the spatial and temporal patterns of this impact and recommend some immediate mitigation measures for decreasing electrocutions.info:eu-repo/semantics/submittedVersio

Dinâmica da decomposição da serapilheira em plantios de seringueira e em fragmento de Mata Atlântica - Minas Gerais.

A compreensão da dinâmica da decomposição da serapilheira é importante para entender o balanço de carbono em ecossistemas florestais e sistemas agrosilviculturais. O presente trabalho mostra dados preliminares de queda de folhas, estoque de serapilheira e o teor de carbono do solo em plantios de seringueira em relação à Mata Atlântica nativa. As áreas de estudo encontram-se na Fazenda Experimental da EPAMIG. Os plantios tinham 20 e 15 anos e pertenciam, respectivamente, aos clones RRIM 600 e IAN 873. O fragmento florestal era constituído de mata secundária tardia, relativamente preservada há mais ou menos 80 anos. Os dados demonstram que a queda de folhas foi semelhante entre os clones (cerca de 1,5 Mg ha -1 ano -1 ), enquanto no fragmento, a produtividade da floresta era quase o dobro (3,2 Mg ha -1 ano -1 ). O estoque de serapilheira foi maior no clone RRIM 600 (1,4 Mg ha -1 ) que no IAN 873 (1,0 Mg ha -1 ). Na mata, o estoque de serapilheira foi maior do que nos clones (4,9 Mg ha -1 ). A presença do horizonte F 2 na mata somada a um peso específico maior e a um coeficiente de decomposição menor indicam uma menor velocidade de decomposição na mata consequentemente, menor mineralização de C. Esses dados sugerem que a produtividade e o padrão de decomposição diferem entre os sítios. Maiores conteúdos de C também foram observados no solo mineral da mata. Tanto o estoque de serapilheira como o teor de C do solo estão relacionados a maiores concentrações de cálcio. O clone RRIM 600 contribui com maiores quantidades de serapilheira e, supostamente, com uma maior fertilidade, consequentemente, esse clone parece ser o melhor indicado para a recuperação de áreas degradadas.bitstream/item/88550/1/bpd53-2004-serapilheira.pd

Cyclotron Maser Emission from Blazar Jets?

We consider the production of electron cyclotron maser emission by low-density, highly magnetized plasmas in relativistic jets. The population inversion required to drive cyclotron maser instability could occur in localized, transient sites where hydromagnetic instabilities, shocks, and/or turbulence lead to magnetic mirroring along current-carrying flux tubes. The maser is pumped as electrons are accelerated by the parallel electric field that develops as a result of the mirror. We estimate the maximum brightness temperatures that can be obtained in a single maser site and in an array of many masers operating simultaneously, under conditions likely to apply in blazar jets. Synchrotron absorption, by relativistic electrons within the jet, presents the largest obstacle to the escape of the maser radiation, and may render most of it invisible. However, we argue that a high brightness temperature could be produced in a thin boundary layer outside the synchrotron photosphere, perhaps in the shear layer along the wall of the jet. Induced Compton scattering provides additional constraints on the maximum brightness temperature of a masing jet. We suggest that recent observations of diffractive scintillation in the blazar J1819+3845, indicating intrinsic brightness temperatures greater than 10^{14} K at 5 GHz, may be explained in terms of cyclotron maser emission. High brightness temperature maser emission from blazar jets may extend to frequencies as high as ~100 GHz, with the maximum possible T_B scaling roughly as 1/frequency. Less massive relativistic jet sources, such as microquasars, are even better candidates for producing cyclotron maser emission, primarily in the infrared and optical bands.Comment: 22 pages, 1 figure, accepted for publication in The Astrophysical Journa

Cell-cell adhesion proteins in melanocytic pilomatrix carcinoma

Tumors of the matrix of rigid structures include matrical tumors of the hairs, nails, and teeth. These tumors share similar phenotypical and signaling features. Although benign matrical hair tumors are among the most common of these tumors, hair matrix tumors containing pigmented melanocytes are very rare. The malignant variant called melanocytic pilomatrix carcinoma contains benign colonizing dendritic melanocytes admixed with the carcinomatous follicular matrical cells

Observations of large-amplitude, parallel, electrostatic waves associated with the Kelvin-Helmholtz instability by the magnetospheric multiscale mission

On 8 September 2015, the four Magnetospheric Multiscale spacecraft encountered a Kelvin-Helmholtz unstable magnetopause near the dusk flank. The spacecraft observed periodic compressed current sheets, between which the plasma was turbulent. We present observations of large-amplitude (up to 100 mV/m) oscillations in the electric field. Because these oscillations are purely parallel to the background magnetic field, electrostatic, and below the ion plasma frequency, they are likely to be ion acoustic-like waves. These waves are observed in a turbulent plasma where multiple particle populations are intermittently mixed, including cold electrons with energies less than 10 eV. Stability analysis suggests a cold electron component is necessary for wave growth

The NASA Airborne Tropical TRopopause EXperiment (ATTREX): High-Altitude Aircraft Measurements in the Tropical Western Pacific

The February through March 2014 deployment of the NASA Airborne Tropical TRopopause EXperiment (ATTREX) provided unique in situ measurements in the western Pacific Tropical Tropopause Layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the CONTRAST and CAST airborne campaigns based in Guam using lower-altitude aircraft (see companion articles in this issue). The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes as well as for evaluation and improvement of global-model representations of TTL processes. The ATTREX data is openly available at https:espoarchive.nasa.gov

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion