The CFEPS Kuiper Belt Survey: Strategy and Pre-survey Results

We present the data acquisition strategy and characterization procedures for the Canada-France Ecliptic Plane Survey (CFEPS), a sub-component of the Canada-France-Hawaii Telescope Legacy Survey. The survey began in early 2003 and as of summer 2005 has covered 430 square degrees of sky within a few degrees of the ecliptic. Moving objects beyond the orbit of Uranus are detected to a magnitude limit of $m_R$=23 -- 24 (depending on the image quality). To track as large a sample as possible and avoid introducing followup bias, we have developed a multi-epoch observing strategy that is spread over several years. We present the evolution of the uncertainties in ephemeris position and orbital elements as the objects progress through the epochs. We then present a small 10-object sample that was tracked in this manner as part of a preliminary survey starting a year before the main CFEPS project. We describe the CFEPS survey simulator, to be released in 2006, which allows theoretical models of the Kuiper Belt to be compared with the survey discoveries since CFEPS has a well-documented pointing history with characterized detection efficiencies as a function of magnitude and rate of motion on the sky. Using the pre-survey objects we illustrate the usage of the simulator in modeling the classical Kuiper Belt.Comment: to be submitted to Icaru

Molecular modeling and anticholinesterasic activity of novel 2-arylaminocyclohexyl N,N-dimethylcarbamates

This work reports a detailed theoretical and experimental study of the novel isomer series cis- and trans-2-arylaminocyclohexyl N,N-dimethylcarbamates as potential inhibitors of cholinesterases. In vitro inhibition assay by Ellman's method with human blood samples showed that the new carbamates are selective to the inhibition of enzyme butyrylcholinesterase (BuChE) with maximum inhibition of 90% and IC50 of 6 and 8 mmol L-1 for the more actives compounds of the series. Molecular modeling studies point to significant differences for the conformations of the compounds in the active sites of enzymes BuChE and acetylcholinesterase (AChE). The results show that the compounds interact more effectively with the active site of enzyme BuChE since the carbamate group is close to the key residues of the catalytic triad.O presente trabalho reporta um estudo teórico e experimental detalhado das séries inéditas de isômeros cis- e trans-N,N-dimetilcarbamatos de cicloexila 2-arilaminossubstituídos como potenciais inibidores de colinesterases. Os testes de inibição in vitro, realizados através do método de Ellman em amostras de sangue humano, mostraram que os novos carbamatos apresentaram boa seletividade frente à inibição da enzima butirilcolinesterase (BuChE), com um máximo de inibição de 90% e IC50 de 6 e 8 mmol L-1 para os compostos mais ativos da série. Os estudos de modelagem molecular apontaram significantes diferenças entre as orientações destes compostos nos sítios ativos das enzimas BuChE e acetilcolinesterase (AChE). Os resultados mostraram que os compostos interagem de forma mais efetiva com o sítio ativo da enzima BuChE, pois o grupo carbamato está próximo aos resíduos chave da tríade catalítica.17981807Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Possible effects on avionics induced by terrestrial gamma-ray flashes

Terrestrial gamma-ray flashes (TGFs) are impulsive (intrinsically sub-millisecond) events associated with lightning in powerful thunderstorms. TGFs turn out to be very powerful natural accelerators known to accelerate particles and generate radiation up to hundreds of MeV energies. The number ratio of TGFs over normal lightning has been measured in tropical regions to be near 10−4. We address in this Article the issue of the possible susceptibility of typical aircraft electronics exposed to TGF particle, gamma ray and neutron irradiation. We consider possible scenarios regarding the intensity, the duration, and geometry of TGFs influencing nearby aircraft, and study their effects on electronic equipment. We calculate, for different assumptions, the total dose and the dose-rate, and estimate single-event-effects. We find that in addition to the electromagnetic component (electrons/positrons, gamma rays) also secondary neutrons produced by gamma-ray photo production in the aircraft structure substantially contribute to single-event effects in critical semiconductors components. Depending on the physical characteristics and geometry, TGFs may deliver a large flux of neutrons within a few milliseconds in an aircraft. This flux is calculated to be orders of magnitude larger than the natural cosmic-ray background, and may constitute a serious hazard to aircraft electronic equipment. We present a series of numerical simulations supporting our conclusions. Our results suggest the necessity of dedicated measurement campaigns addressing the radiative and particle environment of aircraft near or within thunderstorms

Comparative study on myelotoxic and antineoplastic action of Synadenium umbellatum, Vitis vinifera and Resveratrol

Cancer is one of the pathologies that most challenge medicine, not only because of the complexity of its development, but also because of the difficulty of treatment that is not always effective. Due to the significant toxicity and adverse effects profile presented by the main chemotherapeutic agents used to treat neoplasm, there is a constant interest in the search for new drugs that may be a more effective alternative. Therefore, the search for new compounds of plant origin becomes an interesting tool for the discovery of drugs with antitumor activity. Synadenium umbellatum is a plant native to tropical Africa known as “cola-nota”, “hazel”, “cancerous”, “miraculous”, among others. The plant is used by the Brazilian population as having anti-inflammatory, analgesic, antineoplastic properties, among others. However, the literature is lacking on reports of the toxicity of Synadenium umbellatum macerate. Resveratrol is a polyphenolic compound found in different plant species, mainly in grape species (Vitis) and their seeds. Vitis vinifera is a species of grape easily found in several regions, also containing a high concentrations of phenolic compounds, including resveratrol in its fruits, leaves and seeds. Therefore, this study was aimed to evaluate the myelotoxicity of macerate, extract and resveratrol and their antitumor activity in Balb/c mice with Ehrlich tumor. The hematological evaluation was obtained by flow cytometry and the tumors were measured using a pachymeter and the tumor masses by means of weighing. No statistically significant difference was observed between results from the control group and the treatment groups. It was concluded that macerate, crude extract and resveratrol did not demonstrate a myelotoxic effect and did not cause a decrease in tumor mass1928086sem informaçã

Laboratory animals and respiratory allergies: The prevalence of allergies among laboratory animal workers and the need for prophylaxis

OBJECTIVE: Subjects exposed to laboratory animals are at a heightened risk of developing respiratory and allergic diseases. These diseases can be prevented by simple measures such as the use of personal protective equipment. We report here the primary findings of the Laboratory Animals and Respiratory Allergies Study regarding the prevalence of allergic diseases among laboratory animal workers, the routine use of preventive measures in laboratories and animal facilities, and the need for prevention programs. METHODS: Animal handlers and non-animal handlers from 2 Brazilian universities (University of São Paulo and State University of Campinas) answered specific questionnaires to assess work conditions and symptoms. These subjects also underwent spirometry, a bronchial challenge test with mannitol, and skin prick tests for 11 common allergens and 5 occupational allergens (rat, mouse, guinea pig, hamster, and rabbit). RESULTS: Four hundred fifty-five animal handlers (32±10 years old [mean±SD], 209 men) and 387 non-animal handlers (33±11 years old, 121 men) were evaluated. Sensitization to occupational allergens was higher among animal handlers (16%) than non-animal handlers (3%,

Debris disk size distributions: steady state collisional evolution with P-R drag and other loss processes

We present a new scheme for determining the shape of the size distribution, and its evolution, for collisional cascades of planetesimals undergoing destructive collisions and loss processes like Poynting-Robertson drag. The scheme treats the steady state portion of the cascade by equating mass loss and gain in each size bin; the smallest particles are expected to reach steady state on their collision timescale, while larger particles retain their primordial distribution. For collision-dominated disks, steady state means that mass loss rates in logarithmic size bins are independent of size. This prescription reproduces the expected two phase size distribution, with ripples above the blow-out size, and above the transition to gravity-dominated planetesimal strength. The scheme also reproduces the expected evolution of disk mass, and of dust mass, but is computationally much faster than evolving distributions forward in time. For low-mass disks, P-R drag causes a turnover at small sizes to a size distribution that is set by the redistribution function (the mass distribution of fragments produced in collisions). Thus information about the redistribution function may be recovered by measuring the size distribution of particles undergoing loss by P-R drag, such as that traced by particles accreted onto Earth. Although cross-sectional area drops with 1/age^2 in the PR-dominated regime, dust mass falls as 1/age^2.8, underlining the importance of understanding which particle sizes contribute to an observation when considering how disk detectability evolves. Other loss processes are readily incorporated; we also discuss generalised power law loss rates, dynamical depletion, realistic radiation forces and stellar wind drag.Comment: Accepted for publication by Celestial Mechanics and Dynamical Astronomy (special issue on EXOPLANETS

Variação do teor de nitrogênio em ramos produtivos de caquizeiro.

O objetivo deste trabalho foi avaliar a resposta do caquizeiro (Diospyros kaki L.) à adubação nitrogenada. O experimento foi conduzido em um pomar comercial no município de Faxinal, Estado do Paraná, nas coordenadas geográfcas S 23º 57' 35", W51º 13' 34", altitude de 999 metros. A cultivar estudada foi "Giombo". Utilizou-se de 9 tratamentos, sendo uma testemunha sem aplicação de nitrogênio (N), e os demais resultante das épocas de aplicação de N (Maturação fisiológica dos frutos, início de poda, final de florescimento e em 15-12-06), combinadas com duas doses de N (80 e 160 kg/ha). O delineamento experimental foi o de blocos casualizados e 4 repetições. A parcela experimental foi constituída de 3 plantas, sendo a planta central usada para avaliação. A cada quarenta e cinco dias após o início da adubação, foram retirados aleatoriamente de cada tratamento oito ramos produtivos em diferentes pontos da planta. Na folha, os tratamentos IP e MF apresentaram os maiores teores de N na primavera e no verão, e uma diminuição significativa na fase final do ciclo antes da senescência e queda. Na folha e no ramo, todos os tratamentos resultaram em teor de N semelhante no final do ciclo. A época de aplicação, início de poda, foi a época que demonstrou menor variação de N, independentemente da dose

The ESA Hera Mission: Detailed Characterization of the DART Impact Outcome and of the Binary Asteroid (65803) Didymos

Hera is a planetary defense mission under development in the Space Safety and Security Program of the European Space Agency for launch in 2024 October. It will rendezvous in late 2026 December with the binary asteroid (65803) Didymos and in particular its moon, Dimorphos, which will be impacted by NASA’s DART spacecraft on 2022 September 26 as the first asteroid deflection test. The main goals of Hera are the detailed characterization of the physical properties of Didymos and Dimorphos and of the crater made by the DART mission, as well as measurement of the momentum transfer efficiency resulting from DART’s impact. The data from the Hera spacecraft and its two CubeSats will also provide significant insights into asteroid science and the evolutionary history of our solar system. Hera will perform the first rendezvous with a binary asteroid and provide new measurements, such as radar sounding of an asteroid interior, which will allow models in planetary science to be tested. Hera will thus provide a crucial element in the global effort to avert future asteroid impacts at the same time as providing world-leading science