Evaluation of Fomesafen for Broadleaf Weed Control, In Soybeans (Glycine Max)

The lack of effective broadleaf weed control represents one of the major factors having detrimental effects on growth and yield of soybeans. Broadleaf weeds are a serious threat to soybean growers in the southeastern United States. A broad range of herbicides is being used in an effort to control broadleaf weeds in soybeans, and research is still being conducted to find new herbicides that can best work for this purpose. This study involved the use of one these herbicides. It was fomesafen, 5-[2-chloro-4-trifluromethyl) phenoxy]-N-(methyl-sulfonyl)-2-nitrobenzamide, which controls a broad spectrum of broadleaf weeds in soybeans. The experiment was conducted in the summers of 1987 and 1988. Broadleaf weed control treatments with fomesafen at rates at 0.07, 0.14, 0.28, and 0.35 kg ai/ha in single early postemergence and late postemergence applications were evaluated using the herbicide with a nonionic surfactant at 0.25% and 0.50% of the solution. All treatments were compared with a check which did not receive herbicide application. Among the most common broadleaf weeds found in the area under study during the summer of 1987 were morningglories (Ipomoea spp), redroot pigweed (Amaranthus retroflexus L.), jimsonweed (Datura stramonium L.), common lambsquarters (Chenopodium album L.), carpetweed (Moliugo verticillata L.), and prickly sida (Sida spinose L.), For the summer of 1988 the most prevalent broadleaf weeds were morningglories, horsenettle (Solanum carolinense L.), horseweed [Conyza canadensis (L.), Cronq.], and prickly sida. The results of the experiment showed no significant differences between early postemergence and late postemergence treatments. There were no significant differences in broadleaf weed control in treatments which received 0.14, 0.28 and 0.35 kg ai/ha of fomesafen for either 1987 or 1988. Poor broadleaf weed control resulted with the application of fomesafen at its lowest rate (0.07 kg ai/ha). No significant differences were found in broadleaf weed control between concentration of 0.25% and 0.50% of the nonionic surfactant added to fomesafen. Statistically significant yield variation did occur among treatments in 1987. No significant differences in yields were found between any of the herbicide treatments in 1988. Soybean yields were significantly higher in 1988 than in 1987

Modelación espacial de la estructura y distribución de la población de caracol rosado (Aliger gigas) en Pedro Bank, Jamaica

The estimation of reliable indices of abundance for sedentary stocks requires the incorporation of the underlying spatial population structure, including issues arising from the sampling design and zero inflation. We applied seven spatial interpolation techniques [ordinary kriging (OK), kriging with external drift (KED), a negative binomial generalized additive model (NBGAM), NBGAM plus OK (NBGAM+OK), a general additive mixed model (GAMM), GAMM plus OK (GAMM+OK) and a zero-inflated negative binomial model (ZINB) ] to three survey datasets to estimate biomass for the gastropod Aliger gigas on the Pedro Bank Jamaica. The models were evaluated using 10-fold cross-validation diagnostics criteria for choosing the best model. We also compared the best model estimations against two common design methods to assess the consequences of ignoring the spatial structure of the species distribution. GAMM and ZINB were overall the best models but were strongly affected by the sampling design, sample size, the coefficient of variation of the sample and the quality of the available covariates used to model the distribution (geographic location, depth and habitat). More reliable abundance indices can help to improve stock assessments and the development of spatial management using an ecosystem approach.Las estimaciones de índices de abundancia relativa para evaluar poblaciones de especies sedentarias requieren tener en cuenta su estructura espacial, el diseño del muestreo y el alto número de ceros registrados a la hora del muestreo. Para obtener un índice confiable de abundancia para el gasterópodo Aliger gigas en Pedro Bank, Jamaica, se aplicaron siete técnicas de interpolación espacial a tres conjuntos de datos: kriging ordinario (OK), kriging con desviación externa (KED), modelo aditivo generalizado binomial negativo (NBGAM), NBGAM más OK (NBGAM+OK), modelo mixto aditivo general (GAMM), GAMM más OK (GAMM+OK) y modelo binomial negativo con ceros inflados (ZINB). La selección de los mejores modelos espaciales se basó en el criterio de validación cruzada con 10 iteraciones; asimismo, se aplicaron métodos de evaluación comúnmente usados, para destacar la importancia de tener en cuenta la estructura espacial de la distribución de la especie. Los mejores modelos fueron GAMM y ZINB, los cuales fueron fuertemente influenciados por el diseño de muestreo, el tamaño de muestra, el coeficiente de variación y la calidad de las covariables empleadas en la modelación (ubicación geográfica, profundidad y hábitat). Los índices de abundancia más confiables pueden contribuir a mejorar las evaluaciones y desarrollar el manejo espacial con enfoque de ecosistema

Heavy charged Higgs boson decaying into top quark in the MSSM

Observing a heavy charged Higgs boson produced in the near future at the Tevatron or at the LHC would be instant evidence of physics beyond the Standard Model. Whether such a Higgs boson would be supersymmetric or not it could only be decided after accurate prediction of its properties. Here we compute the decay width of the dominant decay of such a boson, namely H^+ -> t \bar{b}, including the leading electroweak corrections originating from large Yukawa couplings within the MSSM. These electroweak effects turn out to be of comparable size to the O(alpha_s) QCD corrections in relevant portions of the MSSM parameter space. Our analysis incorporates the stringent low-energy constraints imposed by radiative B-meson decays.Comment: 10 pages, LaTeX, 5 figs included as a separate file, full postscript version available at ftp://ftp.ifae.es/preprint/ft/uabft433.p

Quantum effects on t→H+bt\to H^{+} b in the MSSM: a window to ``virtual'' supersymmetry?

We analyze the one-loop effects (strong and electroweak) on the unconventional top quark decay mode $t\rightarrow H^{+} b$ within the MSSM. The results are presented in the on-shell renormalization scheme with a physically well motivated definition of $\tan\beta$. The study of this process at the quantum level is useful to unravel the potential supersymmetric nature of the charged Higgs emerging from that decay. As compared with the standard mode $t\rightarrow W^{+} b$, the corrections to $t\rightarrow H^{+} b$ are large, slowly decoupling and persist at a sizeable level even for all sparticle masses well above the LEP 200 discovery range. As a matter of fact, the potential size of the SUSY effects, which amount to corrections of several ten percent, could counterbalance the standard QCD corrections and even make them to appear with the ``wrong'' sign. Therefore, if the charged Higgs decay of the top quark is kinematically allowed -a possibility which is not excluded by the recent measurements of the branching ratio $BR(t\rightarrow W^{+} b)$ at the Tevatron - it could be an invaluable laboratory to search for ``virtual'' supersymmetry. While a first significant test of these effects could possibly be performed at the upgraded Tevatron, a more precise verification would most likely be carried out in future experiments at the LHC.Comment: 60 pages, LaTeX, 25 figs included as a separate file, full postscript version avaliable at ftp://ftp.ifae.es/preprint/ft/uabft397.ps . In this improved version we give an extended discussion of our renormalization framework and of the numerical analysis. Two additional figures are included. Some missprints have been correcte

An Observer-based Switching Algorithm for Safety under Sensor Denial-of-Service Attacks

The design of safe-critical control algorithms for systems under Denial-of-Service (DoS) attacks on the system output is studied in this work. We aim to address scenarios where attack-mitigation approaches are not feasible, and the system needs to maintain safety under adversarial attacks. We propose an attack-recovery strategy by designing a switching observer and characterizing bounds in the error of a state estimation scheme by specifying tolerable limits on the time length of attacks. Then, we propose a switching control algorithm that renders forward invariant a set for the observer. Thus, by satisfying the error bounds of the state estimation, we guarantee that the safe set is rendered conditionally invariant with respect to a set of initial conditions. A numerical example illustrates the efficacy of the approach.Comment: Accepted at the 2023 American Control Conference (ACC

Parameter identification of periodical signals: Application to measurement and analysis of ocean wave forces

This article presents an approach based on state observers to identify the parameters of an unknown periodic force exerted on a mechanical system. This approach comprises two stages and can be executed in real time by using only displacement measurements. The first stage goal is the estimation of the coefficients of a Fourier series that approximates the periodic force. From the estimated coefficients, the phase and the amplitude of the signal can be simultaneously computed; and from the estimated force, in a second stage, the frequencies of the signal can be estimated. To perform the tasks at each stage, two state observers were designed. To show the applicability of the proposed approach, the reconstruction of a wave force affecting a marine structure as well as the computation of the amplitude and phase of its spectral components was taken as case of study. The performance of the state observer was examined by means of simulations and off-line tests carried out with experimental data. Such data were obtained by executing laboratory tests and measuring waves in the Caribbean sea

Dexmedetomidine Clearance Decreases with Increasing Drug Exposure:Implications for Current Dosing Regimens and Target-controlled Infusion Models Assuming Linear Pharmacokinetics

Background: Numerous pharmacokinetic models have been published aiming at more accurate and safer dosing of dexmedetomidine. The vast majority of the developed models underpredict the measured plasma concentrations with respect to the target concentration, especially at plasma concentrations higher than those used in the original studies. The aim of this article was to develop a dexmedetomidine pharmacokinetic model in healthy adults emphasizing linear versus nonlinear kinetics. Methods: The data of two previously published clinical trials with stepwise increasing dexmedetomidine target-controlled infusion were pooled to build a pharmacokinetic model using the NONMEM software package (ICON Development Solutions, USA). Data from 48 healthy subjects, included in a stratified manner, were utilized to build the model. Results: A three-compartment mamillary model with nonlinear elimination from the central compartment was superior to a model assuming linear pharmacokinetics. Covariates included in the final model were age, sex, and total body weight. Cardiac output did not explain between-subject or within-subject variability in dexmedetomidine clearance. The results of a simulation study based on the final model showed that at concentrations up to 2 ng center dot ml(-1), the predicted dexmedetomidine plasma concentrations were similar between the currently available Hannivoort model assuming linear pharmacokinetics and the nonlinear model developed in this study. At higher simulated plasma concentrations, exposure increased nonlinearly with target concentration due to the decreasing dexmedetomidine clearance with increasing plasma concentrations. Simulations also show that currently approved dosing regimens in the intensive care unit may potentially lead to higher-than-expected dexmedetomidine plasma concentrations. Conclusions: This study developed a nonlinear three-compartment pharmacokinetic model that accurately described dexmedetomidine plasma concentrations. Dexmedetomidine may be safely administered up to target-controlled infusion targets under 2 ng center dot ml(-1) using the Hannivoort model, which assumed linear pharmacokinetics. Consideration should be taken during long-term administration and during an initial loading dose when following the dosing strategies of the current guidelines