Radar sounding using the Cassini altimeter waveform modeling and Monte Carlo approach for data inversion observations of Titan's seas

Recently, the Cassini RADAR has been used as a sounder to probe the depth and constrain the composition of hydrocarbon seas on Saturn's largest moon, Titan. Altimetry waveforms from observations over the seas are generally composed of two main reflections: the first from the surface of the liquid and the second from the seafloor. The time interval between these two peaks is a measure of sea depth, and the attenuation from the propagation through the liquid is a measure of the dielectric properties, which is a sensitive property of liquid composition. Radar measurements are affected by uncertainties that can include saturation effects, possible receiver distortion, and processing artifacts, in addition to thermal noise and speckle. To rigorously treat these problems, we simulate the Ku-band altimetry echo received from Titan's seas using a two-layer model, where the surface is represented by a specular reflection and the seafloor is modeled using a facet-based synthetic surface. The simulation accounts for the thermal noise, speckle, analog-to-digital conversion, and block adaptive quantization and allows for possible receiver saturation. We use a Monte Carlo method to compare simulated and observed waveforms and retrieve the probability distributions of depth, surface/subsurface intensity ratio, and subsurface roughness for the individual double-peaked waveform of Ligeia Mare acquired by the Cassini spacecraft in May 2013. This new analysis provides an update to the Ku-band attenuation and results in a new estimate for its loss tangent and composition. We also demonstrate the ability to retrieve bathymetric information from saturated altimetry echoes acquired over Ontario Lacus in December 2008

Efecto de la defoliación post-quema sobre el crecimiento de dos gramíneas nativas en el Caldenal, Argentina

El crecimiento en los pastizales naturales semiáridos puede ser afectado por la longitud de tiempo que el pastoreo es excluido durante el período de regeneración post-fuego. El objetivo de este trabajo a campo fue estudiar el efecto de la defoliación post-fuego en diferentes estados fenológicos: vegetativo (defoliación temprana) y elongación de entrenudos (defoliación tardía) sobre el crecimiento de Piptochaetium napostaense y Poa ligularis, dos gramíneas nativas perennes muy importantes en la región semiárida templada central de Argentina (Caldenal). En general, los tratamientos de defoliación post-quema no afectaron el número de hojas verdes en las macollas de P. napostaense. La defoliación temprana después del tratamiento de fuego generalmente redujo el número de hojas verdes en las macollas de P. ligularis con respecto a las plantas control. Contrariamente, la defoliación tardía usualmente incrementó el número de hojas verdes en las macollas de P. ligularis. Sin embargo, en ambos casos, muy pocas de las diferencias detectadas fueron significativas (p0,05) a aquellas de las plantas no defoliadas. Inmediatamente después de los tratamientos de defoliación temprana y tardía, las tasas de crecimiento relativas de la altura y la longitud verde total de las macollas de las plantas de ambas especies fueron reducidas (p0.05) than values on non-defoliated plants, respectively. Immediately after early- and late-season defoliation treatments, relative growth rates for tiller height and total green length were reduced (p<0.05) on plants of both species with respect to control plants. Our results suggest that a one-year-period without severe defoliations after fire would be at least necessary for not risking the persistence of these perennial grasses in the Caldenal community.Fil: Pelaez, Daniel Valerio. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Boo, Roberto Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Mayor, M. D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Elia, Omar Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Martinez, S. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Nonlocality of cluster states of qubits

We investigate cluster states of qubits with respect to their non-local properties. We demonstrate that a Greenberger-Horne-Zeilinger (GHZ) argument holds for any cluster state: more precisely, it holds for any partial, thence mixed, state of a small number of connected qubits (five, in the case of one-dimensional lattices). In addition, we derive a new Bell inequality that is maximally violated by the 4-qubit cluster state and is not violated by the 4-qubit GHZ state.Comment: 5 pages; paragraph V.B contains a comparison with Guehne et al., quant-ph/041005

Liquid filled canyons on Titan

In May 2013 the Cassini RADAR altimeter observed channels in Vid Flumina, a drainage network connected to Titan’s second largest hydrocarbon sea, Ligeia Mare. Analysis of these altimeter echoes shows that the channels are located in deep (up to ~570 m), steep-sided, canyons and have strong specular surface reflections that indicate they are currently liquid filled. Elevations of the liquid in these channels are at the same level as Ligeia Mare to within a vertical precision of about 0.7 m, consistent with the interpretation of drowned river valleys. Specular reflections are also observed in lower order tributaries elevated above the level of Ligeia Mare, consistent with drainage feeding into the main channel system

Device-independent bounds for Hardy's experiment

In this Letter we compute an analogue of Tsirelson's bound for Hardy's test of nonlocality, that is, the maximum violation of locality constraints allowed by the quantum formalism, irrespective of the dimension of the system. The value is found to be the same as the one achievable already with two-qubit systems, and we show that only a very specific class of states can lead to such maximal value, thus highlighting Hardy's test as a device-independent self-test protocol for such states. By considering realistic constraints in Hardy's test, we also compute device-independent upper bounds on this violation and show that these bounds are saturated by two-qubit systems, thus showing that there is no advantage in using higher-dimensional systems in experimental implementations of such test.Comment: 4 pages, 2 figure

Security Proof for Quantum Key Distribution Using Qudit Systems

We provide security bounds against coherent attacks for two families of quantum key distribution protocols that use $d$-dimensional quantum systems. In the asymptotic regime, both the secret key rate for fixed noise and the robustness to noise increase with $d$. The finite-key corrections are found to be almost insensitive to $d\lesssim 20$.Comment: 5 pages, 1 figure, version 3 corrects equations (9) and (11), and slightly modifies the figure to reflect the change to equation (11

Live Demonstration: Wireless Device for Clinical Pulse Wave Velocity Evaluations

This Live Demonstration presents a low-cost wireless integrated device for clinically evaluating Pulse Wave Velocity (PWV). The system comprises two pen-shaped probes with a high-precision MEMS force sensor on their tips and a base/charging station. The two probes are placed on the femoral and carotid arterial sites and send the pulse wave signals to the base/charging station via Bluetooth. A PC GUI displays the signals and calculates in real-time the PVW value. The visitors can see a real PWV measurement on a dedicated test subject or experience, in the first person, the arterial pulse assessment on their carotid after proper probe sterilization

Pancreatic cancer-derived S-100A8 N-terminal peptide: a diabetes cause?

BACKGROUND: Our aim was to identify the pancreatic cancer diabetogenic peptide. METHODS: Pancreatic tumor samples from patients with (n=15) or without (n=7) diabetes were compared with 6 non-neoplastic pancreas samples using SDS-PAGE. RESULTS: A band measuring approximately 1500 Da was detected in tumors from diabetics, but not in neoplastic samples from non-diabetics or samples from non-neoplastic subjects. Sequence analysis revealed a 14 amino acid peptide (1589.88 Da), corresponding to the N-terminal of the S100A8. At 50 nmol/L and 2 mmol/L, this peptide significantly reduced glucose consumption and lactate production by cultured C(2)C(12) myoblasts. The 14 amino acid peptide caused a lack of myotubular differentiation, the presence of polynucleated cells and caspase-3 activation. CONCLUSIONS: The 14 amino acid peptide from S100A8 impairs the catabolism of glucose by myoblasts in vitro and may cause hyperglycemia in vivo. Its identification in biological fluids might be helpful in diagnosing pancreatic cancer in patients with recent onset diabetes mellitus

WhatsApp Messenger use in oncology: a narrative review on pros and contras of a flexible and practical, non-specific communication tool

The spread of instant messenger systems provides an excellent opportunity and a helpful tool to healthcare professionals. WhatsApp instant messenger use is widely prevalent among health professionals, cancer patients, caregivers and the general population. It is a quick and easy communication tool that may also be used on personal computers and business purposes. WhatsApp instant messenger and other similar tools may be a very useful complement for e-medicine. Instant messaging systems may be helpful, especially in rural areas, in medium- or low-income countries, or to avoid unnecessary travels, improve knowledge and awareness of cancer, monitor home care and support the delivery of home care. The unregulated use of WhatsApp instant messenger requires sound and shared guidelines to assure impeccable professional service. Although a significant number of papers have investigated the roles of social networks in connecting patients to health professionals, there is still a lack of information and scientific data about their uses, benefits and limitations in connecting health providers only for professional communication. The role of instant messenger systems in cancer practice and research needs to be clarified. In this paper, we report a focus on available data, pros and contras of the unregulated use of WhatsApp instant messaging, in the context of e-medicine, as an interprofessional and doctor/patient communication tool in oncology