1,219 research outputs found
Delineating management zones to apply site-specific irrigation in the Venice lagoon watershed
No full textSmartirrigation Apps: Urban Turf
No full textAs freshwater resources become increasingly scarce, efficient irrigation scheduling methods that allow efficient irrigation water uses are required. Migliaccio et al. (2016) have developed an app called Smartirrigation Turf, an easy-to-use mobile tool that delivers information to improve irrigation scheduling for urban turf. The app was only available for Florida and Georgia, but recently, we have made improvements to the app and made it available to any location throughout the contiguous United States. The 7-page major revision, written by Haimanote K. Bayabil, K. W. Migliaccio, J. H. Debastiani Andreis, C. Fraisse, K. T. Morgan, and G. Vellidis, and published by the UF/IFAS Department of Agricultural and Biological Engineering, describes the changes made on the recently released Smartirrigation Turf app.
https://edis.ifas.ufl.edu/ae499
Originally published: Migliaccio, Kati, J. H. Andreis, Clyde Fraisse, Kelly Morgan, and G. Vellidis. 2013. “Smartirrigation Apps: Urban Turf”. EDIS 2013 (9). https://journals.flvc.org/edis/article/view/121158
Smartirrigation Apps: Urban Turf
No full textWe developed an app called Smartirrigation Turf to provide an easy-to-use mobile tool that delivers information to improve irrigation scheduling for urban turf. Using the app instead of a set time-based schedule for irrigation, homeowners and others can provide irrigation amounts to turf that more closely match water needs. This version of the app is applicable in Florida and Georgia and is available to download in the Apple App Store and Google Play Store. This 5-page fact sheet was written by K. W. Migliaccio, J. H. Debastiani Andreis, C. Fraisse, K. T. Morgan, and G. Vellidis, and published by the UF Department of Agricultural and Biological Engineering, October 2013.
http://edis.ifas.ufl.edu/ae49
Developing a soil moisture Decision Support Tool to quantify the occurrence of flash droughts and saturated soil conditions for pasture grasses in the southeast of the United States
No full textopenI disastri legati all'acqua, come la siccità e le inondazioni, sono stati di fondamentale importanza soprattutto nelle aree con elevate esigenze di evapotraspirazione e scarsa capacità di ritenzione idrica del suolo. Sebbene una siccità lampo possa causare gravi conseguenze sui prodotti agricoli, non è stata studiata in modo appropriato. Per migliorare il sistema del modello di coltura, l'umidità del suolo, come variabile chiave da quantificare, è stata monitorata mediante l'uso dei dati della stazione meteorologica e dei sensori del suolo. Per sviluppare l'applicazione del foraggio per irrigazione intelligente come obiettivo principale della ricerca, sono state determinate quattro specie comuni tra cui Bermudagrasses (Cynodon dactylon e C. dactylon 'C. nlemfuensis), Bahiagrass (Paspalum notatum) e Tall Festuca (Lolium arundinaceum). I valori del coefficiente colturale (Kc) sono stati ricavati calcolando l'evapotraspirazione colturale (ETc) utilizzando le registrazioni dei sensori e l'evapotraspirazione di riferimento (ETo), dalle stazioni meteorologiche. I dati dei sensori del suolo sono stati ottenuti da cinque località erbose in modo diverso con le specie sopra menzionate. Le curve del coefficiente colturale sono la base per prevedere il fabbisogno idrico del foraggio. Il prodotto finale, come sistema di supporto alle decisioni, aiuta il decisore a osservare l'entità dell'umidità del suolo e gli stress vegetativi. Significa che le parti interessate potrebbero avere accesso a dati in tempo reale per determinare le pratiche agricole necessarie per evitare lo stress da siccità. D'altra parte, è stato creato un database che sarà disponibile per qualsiasi altro scopo scientifico o governativo. Inoltre, le implicazioni socio-economiche dell'utilizzo di nuovi strumenti di telerilevamento come l'app Forage Smart Irrigation sono innegabili.Water-related disasters such as droughts and floods have been of high critical importance, especially in the areas with high evapotranspiration demands and poor water holding capacity of the soil. Although a flash drought could cause dire consequences on agricultural commodities, has not been studied appropriately. To improve the cropping model system, soil moisture as a key variable to be quantified was monitored by use of data from the weather stations and ground sensors. To develop the smart irrigation forage application as the main goal of the research, four common species including Bermudagrasses (Cynodon dactylon and C. dactylon ‘C. nlemfuensis), Bahiagrass (Paspalum notatum), and Tall Fescue (Lolium arundinaceum) were determined. Crop coefficient (Kc) values were derived through calculating crop evapotranspiration (ETc) using sensors’ records and reference evapotranspiration (ETo), from weather stations. Soil sensors’ data were obtained from five locations grassed diversely with the aforementioned species. Crop coefficient curves are the basis to forecast the water demands of the forage. The final product as a decision support system, helps the decision-maker to observe the magnitude of the soil moisture as well as vegetative stresses. It means the stakeholders could have access to real-time data to determine necessary agricultural practices to avoid drought stress. On the other hand, a database has been created that will be available for any other scientific or governmental purposes. Besides, the socio-economic implications of using new remote sensing tools such as the Forage Smart Irrigation App are undeniable
The Tevatron legacy
No full textThe Tevatron p¯p collider was shut down in 2011, after almost 10 years of high-performance operation at a center-of-mass energy of 1.96TeV. The two experiments, CDF and D0, continue to analyze the collected data, aiming to extract all possible information on validation of the standard model and on searches for new physics. A short review of some legacy measurements at the Tevatron, and of the impact of the Tevatron program in high-energy physics, is presented
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Top quark mass: Latest CDF results, Tevatron combination and electroweak implications
No full textA summary of the most up-to-date top quark mass measurements at CDF is presented. These analyses use top-antitop candidate events detected in the CDF experiment at the Tevatron collider with an integrated luminosity of up to {approx}3/fb. The combination of all those measurements together with the corresponding top mass measurements from the concurrently running D0 experiment at the Tevatron yields a world average of M{sub t} = [173.1 {+-} 0.6(stat.) {+-} 1.1(syst.)] GeV/c{sup 2}
Tevatron greatest hits
No full textThe Tevatron collider led the World energy frontier program in particle physics during the late 20th and early 21st centuries. During this exciting period the standard model of particle physics was in its final stages of development and the search for physics beyond the standard model became one of the main research topics. In this review article we summarize the design and performance of the Tevatron collider and its two detectors, CDF and D0, as well as their evolution. Highlights of the Tevatron scientific results are provided, including the discovery of the top quark and measurements of its properties, studies and discoveries of the particles containing heavy quarks, precision studies of the strong and electroweak forces, searches for beyond the standard model particles and interactions, as well as the hunt for the Higgs boson. © 2022 IOP Publishing Ltd
Approaching the CDF Top Quark Mass Legacy Measurement in the Lepton+Jets channel with the Matrix Element Method
No full textThe discovery of the bottom quark in 1977 at the Tevatron Collider triggered the search for its partner in the third fermion isospin doublet, the top quark, which was discovered 18 years later in 1995 by the CDF and D0 experiments during the Tevatron Run I. By 1990, intensive efforts by many groups at several accelerators had lifted to over 90 GeV the lower mass limit, such that since then the Tevatron became the only accelerator with high-enough energy to possibly discover this amazingly massive quark. After its discovery, the determination of top quark properties has been one of the main goals of the Fermilab Tevatron Collider, and more recently also of the Large Hadron Collider (LHC) at CERN. Since the mass value plays an important role in a large number of theoretical calculations on fundamental processes, improving the accuracy of its measurement has been at any time a goal of utmost importance.
Predominantly produced in ttbar pairs at the Tevatron through strong interactions in ppbar collisions, the top quark mass was measured for the first time by CDF with a value of 176 ± 13 GeV/c^2, showing that this particle was by far the heaviest known elementary particle. This has raised many questions on whether the top quark may play a special role in the Standard Model (SM), in particular in the electroweak symmetry breaking. Due to the huge mass and the very short lifetime (∼ 5 × 10−25 s), about six times shorter than the strong interaction timescale, the top quark decays weakly before hadronization into a W boson and a b quark , giving the chance to study the properties of a bare quark. Top quark pair events are thus characterized by the decay of their two final state W bosons. This leads the ttbar pairs to generate the experimental signatures of two jets associated with the hadronization of the bottom quarks and either a single lepton (e, μ, τ), one undetected neutrino and two light quark jets (lepton+jets channel), or four light quark jets (all-jets channel), or two leptons (ee, eμ, μμ, eτ, μτ, ττ) and two undetected neutrinos (dilepton channels). Up to now, because of its difficult experimental signatures the τ lepton was not exploited in the mass studies.
Different approaches have been followed by the Tevatron experiments to determine the top quark mass. A very powerful technique is the Matrix Element (ME) method which determines the likelihood of observing an event under both ttbar and background hypotheses. The hypotheses are determined from the entire kinematic information associated to every single event by integrating the matrix element of the process over the multidimensional phase space describing the final state. For a given sample of selected events, the parameters to be measured are then determined as those values that maximize the overall likelihood. The superior statistical sensitivity of this method, with respect to other methods based on distribution-fitting, is due to the completeness of the information exploited in each event.
Since the top quark mass is a fundamental parameter of the SM, the CDF Collaboration has decided to make a major effort in order to produce its most precise measurement as a "legacy" of the experiment. A number of improvements over previous measurements are still possible as mentioned below, noticeably comparing the signal candidates not only to the signal expectation, but also to the expectation of the dominant background process (W +jets), whose SM matrix element is now made available to the Collaboration. This thesis provides an overview of the preparatory studies to the final CDF measurement of the top quark mass. We investigate the lepton + jets channel with the full integrated luminosity of Run II (9.0 fb−1). Our analysis uses the ME method to calculate a ttbar likelihood as a bi-dimensional function of the assumed top mass mt and ∆JES. ∆JES parametrizes the uncertainty in our knowledge of the jet energy scale. It is a shift applied to all jet energies in units of the jet-dependent systematic error. By introducing this parameter into the likelihood, we can use as a constraint the known W mass to determine the optimal ∆JES and thereby reduce the final systematic error on the measured top quark mass. For the first time in CDF analyses, we include the background ME modeling in the likelihood integration, with an expected significant reduction of the systematic error of the final result.
The massive calculations required by this double ME method imposed to develop an unconventional, less time-consuming, integration method over the phase space of the events kinematics. In order to evaluate the multidimensional integrals, we employ the "Quasi Monte Carlo" (QMC) technique, based on deterministic sequences generated by choosing points approximately equally spaced in the integration space, such that equal phase space volumes contain approximately equal number of points. This technique significantly reduces the time required to integrate an event, allowing us to reduce greatly the integration time needed to reach the required precision. It also imposes extensive studies to make sure that no bias is introduced relative to a standard MC calculation.
The present thesis describes in detail the contributions given by the candidate to the massive preparation work needed to make the new analysis possible, during her 8 months long stay at Fermilab. These include selection of the candidates within looser cuts than in the past, estimate of the expected number of signal and background events, evaluation of the acceptance, model comparison of the final validation plots, optimization of the integration method and of its systematic error, and more as described in chapters 4 to 7.
Chapter 1 gives a brief introduction of top quark physics. Some previous mass measurements, as well as the refinements introduced in our analysis, are discussed.
Chapter 2 contains the description of the Tevatron accelerator complex and the CDF II detector.
Chapter 3 describes the reconstruction of the physical objects on which the event analysis relies.
The event selection is described in Chapter 4, where the complete list of the selection requirements and the estimation of the sample composition are presented, as well as the comparison between model and data.
Chapter 5 explains the ME method in detail, examining each part of the likelihood expression, and Chapter 6 deals with the QMC integration employed in the analysis.
In Chapter 7 the current status of the analysis and the future steps required to perform the measurement are described. Preliminarily to the final analysis of real data, future studies will include a calibration procedure and evaluation of systematic errors by means of pseudo-experiments. The goal of the measurement is to reach a total error of about 0.6 GeV/c^2, about 20% less than the present error of the world-averaged mass value. The candidate is planning to contribute from a distance to this final part of the measurement
Water quality monitoring, control and management (WQMCM) framework using collaborative wireless sensor networks
No full textImproving water quality is of global concern, with agricultural practices being the major contributors to reduced water quality. The reuse of nutrient-rich drainage water can be a valuable strategy to gain economic-environmental benefits. However, currently the tools and techniques to allow this do not exist. Therefore, we have proposed a framework, WQMCM, which utilises increasingly common local farm-scale networks across a catchment, adding provision for collaborative information sharing. Using this framework, individual sub-networks can learn their environment and predict the impact of catchment events on their locality, allowing dynamic decision making for local irrigation strategies. Since resource constraints of network nodes (e.g. power consumption, computing power etc.) require a simplified predictive model for discharges, therefore low-dimensional model parameters are derived from the existing National Resource Conservation Method (NRCS), utilising real-time field values. Evaluation of the predictive models, developed using M5 decision trees, demonstrates accuracy of 84-94% compared with the traditional NRCS curve number model. The discharge volume and response time model was tested to perform with 6% relative root mean square error (RRMSE), even for a small training set of around 100 samples; however the discharge response time model required a minimum of 300 training samples to show reasonable performance with 16% RRMS
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