Model reduction for analysis of cascading failures in power systems

In this paper, we apply a principal-orthogonal decomposition based method to the model reduction of a hybrid, nonlinear model of a power network. The results demonstrate that the sequence of fault events can be evaluated and predicted without necessarily simulating the whole system

Virial series for inhomogeneous fluids applied to the Lennard-Jones wall-fluid surface tension at planar and curved walls

We formulate a straightforward scheme of statistical mechanics for inhomogeneous systems that includes the virial series in powers of the activity for the grand free energy and density distributions. There, cluster integrals formulated for inhomogeneous systems play a main role. We center on second order terms that were analyzed in the case of hard-wall confinement, focusing in planar, spherical and cylindrical walls. Further analysis was devoted to the Lennard-Jones system and its generalization the 2k-k potential. For this interaction potentials the second cluster integral was evaluated analytically. We obtained the fluid-substrate surface tension at second order for the planar, spherical and cylindrical confinement. Spherical and cylindrical cases were analyzed using a series expansion in the radius including higher order terms. We detected a $\ln R^{-1}/R^{2}$ dependence of the surface tension for the standard Lennard-Jones system confined by spherical and cylindrical walls, no matter if particles are inside or outside of the hard-walls. The analysis was extended to bending and Gaussian curvatures, where exact expressions were also obtained.Comment: 15 pages, 6 figure

Temporal and Spatial Aspects of Gas Release During the 2010 Apparition of Comet 103P/Hartley-2

We report measurements of eight primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, C2H2, H2CO, and NH3) and two product species (OH and NH2) in comet 103P/Hartley-2 using high dispersion infrared spectroscopy. We quantified the long- and short-term behavior of volatile release over a three-month interval that encompassed the comet's close approach to Earth, its perihelion passage, and flyby of the comet by the Deep Impact spacecraft during the EPOXI mission. We present production rates for individual species, their mixing ratios relative to water, and their spatial distributions in the coma on multiple dates. The production rates for water, ethane, HCN, and methanol vary in a manner consistent with independent measures of nucleus rotation, but mixing ratios for HCN, C2H6, & CH3OH are independent of rotational phase. Our results demonstrate that the ensemble average composition of gas released from the nucleus is well defined, and relatively constant over the three-month interval (September 18 through December 17). If individual vents vary in composition, enough diverse vents must be active simultaneously to approximate (in sum) the bulk composition of the nucleus. The released primary volatiles exhibit diverse spatial properties which favor the presence of separate polar and apolar ice phases in the nucleus, establish dust and gas release from icy clumps (and also, directly from the nucleus), and provide insights into the driver for the cyanogen (CN) polar jet. The spatial distributions of C2H6 & HCN along the near-polar jet (UT 19.5 October) and nearly orthogonal to it (UT 22.5 October) are discussed relative to the origin of CN. The ortho-para ratio (OPR) of water was 2.85 \pm 0.20; the lower bound (2.65) defines Tspin > 32 K. These values are consistent with results returned from ISO in 1997.Comment: 18 pages, 3 figures, to be published in: Astrophysical Journal Letter

Análise de custo e benefício de duas tecnologias na cafeicultura, Ouro Preto d'Oeste, RO, 2007.

O presente trabalho avalia o retorno econômico da adoção das tecnologias da poda e da adubação em unidades de produção do município de Ouro Preto do Oeste, RO.bitstream/CPAF-RO-2010/13274/1/cot331-cafeicultura.pd

Systematic review of reduced therapy regimens for children with low risk febrile neutropenia

PURPOSE: Reduced intensity therapy for children with low-risk febrile neutropenia may provide benefits to both patients and the health service. We have explored the safety of these regimens and the effect of timing of discharge. METHODS: Multiple electronic databases, conference abstracts and reference lists were searched. Randomised controlled trials (RCT) and prospective observational cohorts examining the location of therapy and/or the route of administration of antibiotics in people younger than 18 years who developed low-risk febrile neutropenia following treatment for cancer were included. Meta-analysis using a random effects model was conducted. I (2) assessed statistical heterogeneity not due to chance. Registration: PROSPERO (CRD42014005817). RESULTS: Thirty-seven studies involving 3205 episodes of febrile neutropenia were included; 13 RCTs and 24 prospective observational cohorts. Four safety events (two deaths, two intensive care admissions) occurred. In the RCTs, the odds ratio for treatment failure (persistence, worsening or recurrence of fever/infecting organisms, antibiotic modification, new infections, re-admission, admission to critical care or death) with outpatient treatment was 0.98 (95% confidence interval (95%CI) 0.44-2.19, I (2) = 0 %) and with oral treatment was 1.05 (95%CI 0.74-1.48, I (2) = 0 %). The estimated risk of failure using outpatient therapy from all prospective data pooled was 11.2 % (95%CI 9.7-12.8 %, I (2) = 77.2 %) and using oral antibiotics was 10.5 % (95%CI 8.9-12.3 %, I (2) = 78.3 %). The risk of failure was higher when reduced intensity therapies were used immediately after assessment, with lower rates when these were introduced after 48 hours. CONCLUSIONS: Reduced intensity therapy for specified groups is safe with low rates of treatment failure. Services should consider how these can be acceptably implemented

Adaptive forest governance to face land use change impacts in Italy: a review

Il cambiamento dell’uso del suolo è uno dei driver principali della riduzione della resilienza ecosistemica, così come della perdita di biodiversità e approvvigionamento di servizi. Rappresenta una sfida peculiare, specialmente negli ambienti mediterranei, dove i fenomeni di abbandono e ricolonizzazione naturale stanno minacciando in modo sempre più crescente la capacità delle foreste di fornire benefici alle comunità locali. In queste condizioni, il sistema di governance forestale è chiamato a bilanciare gli impatti del cambiamento dell’uso del suolo con l’assicurazione della salute e della stabilità degli ecosistemi forestali, al fine di garantire la sostenibilità a lungo termine degli ambienti, soprattutto di quelli marginali. Questo lavoro si propone di analizzare in modo più approfondito gli impatti del cambiamento dell’uso del suolo sugli ecosistemi forestali negli ambienti montani italiani. In primo luogo, esegue un’analisi bibliografica dei concetti legati al cambiamento dell’uso del suolo e all’approvvigionamento dei servizi ecosistemici, dalla scala globale a quella locale. In seguito, indaga le relazioni fra le potenzialità adattive di gestione e pianificazione forestali e il cambiamento dell’uso del suolo. Infine, vengono proposte alcune strategie future di possibili strumenti di governance adattiva per affrontare i cambiamenti dell’uso del suolo. Questa infatti può migliorare la resilienza degli ecosistemi forestali riducendo il gap nel campo della ricerca tra il contesto nazionale e quello globale, utilizzando strumenti di valutazione e monitoraggio per simulare cambiamenti e disturbi esterni, e adottando strategie e misure politiche coerenti a scala locale.Land use change is one of the most important drivers for the reduction of ecosystem resilience, and the loss ofbiodiversity and services provision. This is a peculiar challenge, especially in Mediterranean mountain environments,where abandonment and forest transition phenomena increasingly threaten the forest capacity to provide benefits for local communities. Under these conditions, forest governance is called to balance the landuse change impacts and the health and stability of forest ecosystems, in order to ensure the long-term sustainabilityof such marginal environments. This paper aims at deeper understanding the impacts of land use change on forest ecosystem on mountain environments in Italy. At first, a downscaled review on the conceptsof land use change and ecosystem services provision is carried out. Then, according to the review results, therelationships between adaptive capacity of forest management and planning, and land use change is deeply described. Finally, future-oriented strategies of adaptive governance to face land use change are proposed. Inthe context of land use change, adaptive governance can improve forest resilience through filling the researchgaps between the national and the global contexts, adopting monitoring and assessment tools to simulate external changes and disturbances, and effectively implement consistent policy measures and strategies at localscale

Interpreting Methanol v(sub 2)-Band Emission in Comets Using Empirical Fluorescence g-Factors

For many years we have been developing the ability, through high-resolution spectroscopy targeting ro-vibrational emission in the approximately 3 - 5 micrometer region, to quantify a suite of (approximately 10) parent volatiles in comets using quantum mechanical fluorescence models. Our efforts are ongoing and our latest includes methanol (CH3OH). This is unique among traditionally targeted species in having lacked sufficiently robust models for its symmetric (v(sub 3) band) and asymmetric (v(sub 2) and v(sub 9) bands) C-H3 stretching modes, required to provide accurate predicted intensities for individual spectral lines and hence rotational temperatures and production rates. This has provided the driver for undertaking a detailed empirical study of line intensities, and has led to substantial progress regarding our ability to interpret CH3OH in comets. The present study concentrates on the spectral region from approximately 2970 - 3010 per centimeter (3.367 - 3.322 micrometer), which is dominated by emission in the (v(sub 7) band of C2H6 and the v(sub 2) band of CH3OH, with minor contributions from CH3OH (v(sub 9) band), CH4 (v(sub 3)), and OH prompt emissions (v(sub 1) and v(sub 2)- v(sub 1)). Based on laboratory jet-cooled spectra (at a rotational temperature near 20 K)[1], we incorporated approximately 100 lines of the CH3OH v(sub 2) band, having known frequencies and lower state rotational energies, into our model. Line intensities were determined through comparison with several comets we observed with NIRSPEC at Keck 2, after removal of continuum and additional molecular emissions and correcting for atmospheric extinction. In addition to the above spectral region, NIRSPEC allows simultaneous sampling of the CH3OH v(sub 3) band (centered at 2844 per centimeter, or 3.516 micrometers and several hot bands of H2O in the approximately 2.85 - 2.9 micrometer region, at a nominal spectral resolving power of approximately 25,000 [2]. Empirical g-factors for v(sub 2) lines were based on the production rate as determined from the v(sub 3) Q-branch intensity; application to comets spanning a range of rotational temperatures (approximately 50 - 90 K) will be reported. This work represents an extension of that presented for comet 21P/Giacobini-Zinner at the 2010 Division for Planetary Sciences meeting [3]. Our empirical study also allows for quantifying CH3OH in comets using IR spectrometers for which the v(sub 3) and v(sub 2) bands are not sampled simultaneously, for example CSHELL/NASA IRTF or CRIRES/VLT

The Volatile Fraction of Comets as Quantified at Infrared Wavelengths - An Emerging Taxonomy and Implications for Natal Heritage

It is relatively easy to identify the reservoir from which a given comet was ejected. But dynamical models demonstrate that the main cometary reservoirs (Kuiper Belt, Oort Cloud) each contain icy bodies that formed in a range of environments in the protoplanetary disk, and the Oort Cloud may even contain bodies that formed in disks of sibling stars in the Sun s birth cluster. The cometary nucleus contains clues to the formative region(s) of its individual components. The composition of ices and rocky grains reflect a range of processes experienced by material while on the journey from the natal interstellar cloud core to the cometary nucleus. For that reason, emphasis is placed on classifying comets according to their native ices and dust (rather than orbital dynamics). Mumma & Charnley [1] reviewed the current status of taxonomies for comets and relation to their natal heritage

C/2013 R1 (Lovejoy) at IR Wavelengths and the Variability of CO Abundances among Oort Cloud Comets

We report production rates, rotational temperatures, and related parameters for gases in C/2013 R1 (Lovejoy) using the Near InfraRed SPECtrometer at the Keck Observatory, on six UT dates spanning heliocentric distances (R_h ) that decreased from 1.35 AU to 1.16 AU (pre-perihelion). We quantified nine gaseous species (H_2O, OH^*, CO, CH^4, HCN, C_2H_6, CH_3OH, NH_3, and NH_2) and obtained upper limits for two others (C_2H_2 and H_2CO). Compared with organics-normal comets, our results reveal highly enriched CO, (at most) slightly enriched CH_3OH, C_2H_6, and HCN, and CH_4 consistent with "normal", yet depleted, NH_3, C_2H_2, and H_2CO. Rotational temperatures increased from ~50 K to ~70 K with decreasing R_h , following a power law in R_h of –2.0 ± 0.2, while the water production rate increased from 1.0 to 3.9 × 10^(28) molecules s^(–1), following a power law in R_h of –4.7 ± 0.9. The ortho-para ratio for H_2O was 3.01 ± 0.49, corresponding to spin temperatures (T_(spin)) ≥ 29 K (at the 1σ level). The observed spatial profiles for these emissions showed complex structures, possibly tied to nucleus rotation, although the cadence of our observations limits any definitive conclusions. The retrieved CO abundance in Lovejoy is more than twice the median value for comets in our IR survey, suggesting this comet is enriched in CO. We discuss the enriched value for CO in comet C/2013 R1 in terms of the variability of CO among Oort Cloud comets