285 research outputs found
Estimating evaporation from a wet grassland
International audienceWet grasslands are being restored across the UK and Europe to reinstate their high biodiversity following over 50 years of drainage and conversion to arable agriculture. The water balance of many wet grasslands is dominated by precipitation and evaporation and it is essential to quantify evaporation rates to understand the hydrological functioning of wetlands and the implications for water resources in catchments where wetlands are being restored. This paper considers data from direct measurements of evaporation from the Pevensey Levels wet grassland using the eddy correlation method. Equations are derived to predict actual evaporation using meteorological data on the site or from standard meteorological station observations. It was found that evaporation could be estimated reliably from meteorological variables, such as wind speed, temperature and humidity and by water availability. It was also found that when water availability is high, evaporation is high and may exceed reference evaporation values, raising questions over the deployment of the two-step Penman-Monteith model unless reliable crop coefficients and relative evaporation figures can be determined
Inclusion of higher order terms for small-signal (modal) analysis: Committee report - task force on assessing the need to include higher order terms for small-signal (modal) analysis
© 2005 IEEE.This paper summarizes the work done by the Task Force on Assessing the Need to Include Higher Order Terms for Small-Signal (Modal) Analysis. This Task Force was created by the Power System Dynamic Performance Committee to investigate the need to include higher order terms for small signal (modal) analysis. The focus of the work reported here is on establishing and documenting the practical significance of these terms in stability analysis using the method of Normal Forms. Special emphasis was placed on determining and describing conditions when higher order terms need to be included to accurately describe modal interactions. Test cases were developed on a standard test system to demonstrate the application of appropriate indices to detect the occurrence of nonlinear interaction and hence the need for higher order terms in stability analyzes. The use of the higher order terms in the site selection for a damping controller is also documented.Sanchez-Gasca, Juan J.,Vittal, Vijay; Gibbard, Michael J.; Messina, Arturo Roman; Vowles, David J.; Liu, Shu; Annakkage, Udaya D
La Cantalera: an exceptional window onto the vertebrate biodiversity of the Hauterivian-Barremian transition in the Iberian Peninsula.
La Cantalera is an accumulation site for fossil vertebrates consisting mainly of teeth and isolated postcranial remains. It has the greatest vertebrate biodiversity of any site from the Hauterivian-Barremian transition in the Iberian Peninsula. Up to now, 31 vertebrate taxa have been recognized: an osteichthyan (Teleostei indet.), two amphibians (Albanerpetonidae indet. and Discoglossidae indet.), a chelonian (Pleurosternidae? indet.), a lizard (Paramacellodidae? indet.), four crocodylomorphs (cf. Theriosuchus sp., Bernissartiidae indet., Goniopholididae indet., cf. Lisboasaurus sp.), two pterosaurs (Istiodactylidae? indet., Ornithocheiridae? indet.), four ornithopod dinosaurs (Iguanodontoidea indet., Hadrosauroidea? indet., “Hypsilophodontidae” indet., Rhabdodontidae? indet.), a thyreophoran (Polacanthidae indet.), a sauropod (Euhelopodidae indet.), eleven theropods (Carcharodontosauridae? indet., Baryonychinae indet., aff. Paronychodon sp., Maniraptora indet. 1-3, Dromaeosaurinae indet. 1-3, Velociraptorinae indet., Avialae? indet.) and three or four multituberculate mammals (Cantalera abadi, Eobaatar sp., Plagiaulacidae or Eobaataridae gen. et sp. indet., “Plagiaulacida” indet.). Nine ootaxa have also been distinguished at the site of La Cantalera. Oofamilies assigned to dinosaurs (Elongaloolithidae, Prismatoolithidae, cf. Spheroolithidae), to crocodiles (Krokolithidae) and eggshells of two oofamilies incertidae sedis are represented. This association is consistent with the record of bone and tooth remains from the site. La Cantalera was formed in a marshy environment where there was an intermittent body of water. The great majority of the vertebrate fossil remains lack evidence of transport, so the preserved association is a good representation of the vertebrate ecosystem in or around the marshy area of La Cantalera. The vertebrate association of La Cantalera displays certain differences with respect to those from lacustrine environments of the Hauterivian-Barremian transition of the Iberian Range. These differences include, for example, the absence of Chondrichthyes, the merely token presence of the osteichthyans, the scarcity of chelonians, the presence of exclusively multituberculate mammals, the lower diversity of sauropods and the greater diversity of theropods
Polynomial Heuristic Algorithms for Inconsistency Characterization in Firewall Rule Sets
Firewalls provide the first line of defence of nearly all networked institutions today. However, Firewall ACLs could have inconsistencies, allowing traffic that should be denied or vice versa. In this paper, we analyze the inconsistency characterization problem as a separate problem of the diagnosis one, and propose formal definitions in order to characterize one-to-many inconsistencies. We identify the combinatorial part of the problem that generates exponential complexities in combined diagnosis and characterization algorithms proposed by other authors. Then we propose a decomposition of the combinatorial problem in several smaller combinatorial ones, which can effectively reduce the complexity of the problem. Finally, we propose an approximate heuristic and algorithms to solve the problem in worst case polynomial time. Although many algorithms have been proposed to address this problem, all of them are combinatorial. The presented algorithms are an heuristic way to solve the problem with polynomial complexity. There are no constraints on how rule field ranges are expressed
Focused ultrasound for opening blood-brain barrier and drug delivery monitored with positron emission tomography
Focused ultrasound (FUS) is a minimally-invasive technology used for treatment of many diseases, including diseases related to the colon, uterus, prostate, and brain. Although it has been mainly used for ablative procedures, the ability of FUS to open the blood-brain barrier (BBB) presents a promising new application. However, the mechanism of BBB opening by FUS remains unclear. This review focuses on the use of FUS to open the BBB for enhancing drug delivery and investigating how Positron Emission Tomography (PET) provides insight into the underlying mechanism
Análisis fenológico en pastizales de dehesa
P. 17-30Se estudia la dinámica de los pastizales desde el punto de vista de las
manifestaciones fenológicas en la zona de dehesas de la provincia de
Salamanca, y a lo largo de los períodos prever nal, vernal, y estival.
Dichos períodos pueden considerarse los más significativos y los que
poseen mayor número de matices diferenciales entre los distintos tipos de
pastizal. Se controlaron 21 parcelas pertenecientes a las comunidades más
representativas de la zona.
La información obtenida se ha simplificado, con objeto de ofrecer una
visión más general de los aspectos fenológicos de cada tipo de pastizal,
resumiendo las observaciones realizadas por especie para el conjunto de los
pastizales de semejante categoría fenológica. Para este trabajo se han
seleccionado las especies dominantes y las características. Los resultados de
este estudio —fundamentalmente descriptivo —se representan gráficamente
distinguiendo los tipos fundamentales de pastizal en función del
gradiente oligotrofia eutrofiaN
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Development and Validation of WECC Variable Speed Wind Turbine Dynamic Models for Grid Integration Studies
This paper describes reduced-order, simplified wind turbine models for analyzing the stability impact of large arrays of wind turbines with a single point of network interconnection
The state of art of the drought studies in Spain
Póster elaborado para el WCRP Workshop on Drought Predictability and Prediction in a Changing Climate celebrado en Barcelona del 2 al 4 de marzo de 201
Addressing the high cervical cancer rates along the Texas-Mexico border through community outreach, patient navigation, and provider training/telementoring
Objective: Cervical cancer incidence and mortality rates are 68% and 57% higher, respectively, along the Texas-Mexico border compared with the rest of the United States. This is likely due to a combination of low health literacy, limited access to affordable screening, and a lack of trained personnel to perform colposcopy, loop electrosurgical excision procedures (LEEP), and appropriate management of women with pre-invasive disease. The objective of our study was to increase cervical cancer screening, diagnosis, and treatment rates in the Rio Grande Valley (RGV).
Method: We initiated a comprehensive program at two health centers and one mobile clinic in the RGV consisting of (1) a public education program designed for community health workers to teach women about cervical cancer screening and HPV vaccination coupled with patient navigation to participating clinics; (2) colposcopy and LEEP training for physicians and advanced-practice providers through locally held hands-on courses and mentoring program; and (3) implementation of Project ECHO (Extension for Community Health Outcomes), a well-established telementoring program using video conferencing to connect academic specialists with community providers for case-based learning. We compared screening, diagnosis, and treatment rates pre- and post-program implementation.
Results: From November 2014 to June 2018, local providers screened 19,028 women with Pap ± HPV testing (baseline 12,460, 53% increase); performed colposcopy on 2,644 women with abnormal screening results (baseline 945, 180% increase); and performed 483 LEEP procedures for treatment of cervical dysplasia (baseline 0). Ten women were diagnosed with invasive cancer and navigated to one of the participating gynecologic oncologists for treatment (baseline N/A). Five additional providers in the RGV completed the mentoring program to be certified to perform colposcopy (100% increase from baseline of 5) and two additional providers to perform LEEP (baseline 0). ECHO telementoring video conferences have been held every two weeks for a total 94 sessions (average of 22 participants/session) with 182 patient cases presented and discussed.
Conclusion: Our comprehensive approach has led to an increase in the number of women undergoing cervical cancer screening and diagnosis/treatment of dysplasia. If sustained, we anticipate these efforts will decrease cervical cancer rates in the RGV. The program is currently being expanded to additional medically underserved regions of Texas
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