A global evaluation of streamflow drought characteristics

How drought is characterised depends on the purpose and region of the study and the available data. In case of regional applications or global comparison a standardisation of the methodology to characterise drought is preferable. In this study the threshold level method in combination with three common pooling procedures is applied to daily streamflow series from a wide range of hydrological regimes. Drought deficit characteristics, such as drought duration and deficit volume, are derived, and the methods are evaluated for their applicability for regional studies. Three different pooling procedures are evaluated: the moving-average procedure (MA-procedure), the inter-event time method (IT-method), and the sequent peak algorithm (SPA). The MA-procedure proved to be a flexible approach for the different series, and its parameter, the averaging interval, can easily be optimised for each stream. However, it modifies the discharge series and might introduce dependency between drought events. For the IT-method it is more difficult to find an optimal value for its parameter, the length of the excess period, in particular for flashy streams. The SPA can only be recommended as pooling procedure for the selection of annual maximum series of deficit characteristics and for very low threshold levels to ensure that events occurring shortly after major events are recognized. Furthermore, a frequency analysis of deficit volume and duration is conducted based on partial duration series of drought events. According to extreme value theory, excesses over a certain limit are Generalized Pareto (GP) distributed. It was found that this model indeed performed better than or equally to other distribution models. In general, the GP-model could be used for streams of all regime types. However, for intermittent streams, zero-flow periods should be treated as censored data. For catchments with frost during the winter season, summer and winter droughts have to be analysed separately

Objectively estimating tropical cyclone intensity and wind structure using the advanced microwave sounding unit

Includes bibliographical references.Estimating tropical cyclone (TC) intensity and structure is becoming increasingly important in light of population expansion along coastal regions. The two most commonly used techniques for estimating TC intensity, the Dvorak Technique and the Objective Dvorak Technique (ODT), utilize visible and infrared satellite imagery. However, both have limitations, as do observing techniques of TC wind structure. Satellite-borne passive microwave radiometers provide an opportune alternative for near real-time assessments of TC maximum sustained winds and wind radii. The first Advanced Microwave Sounding Unit (AMSU), aboard the NOAA-15 polar orbiting satellite, is the first NOAA instrument with sufficient resolution to do so. In this study, data derived from AMSU temperature, pressure, and wind retrievals are used to make objective intensity and wind radii estimates for tropical disturbances in the Atlantic and East Pacific basins. To approximate TC maximum sustained winds and azimuthally averaged wind radii of 34, 50, and 64 kt winds, algorithms are developed via correlations and multiple linear regressions from AMSU data from the 1999 tropical season; they then are tested independently on the 2000 tropical season data Additionally, the AMSU-derived estimates of the azimuthally averaged wind radii are used with a modified Rankine vortex model to assess the wind radii asymmetrically, specifically in the northeast (NE), northwest (NW), southeast (SE), and southwest (SW) quadrants of the TC. Validation data are from the National Hurricane Center (NHC) best track data for the intensity estimates, and from the NHC operational forecast advisories for the average and asymmetric wind radii estimates. Results show the objective AMSU algorithm is comparable to the ODT for estimating TC intensity in the Atlantic, with a root mean square error (RMSE) of 13 kts. The RMSE increases slightly to 16 kts for both basins combined. In general, the AMSU algorithm has a tendency to over (under) approximate the intensity of weak (strong) TCs. For the AMSU-estimated azimuthally averaged 34, 50, and 64 kt wind radii, the mean absolute errors (MAE) are 16, 17, and 8 nautical miles (nm), respectively. With respect to the average radii of each, these correspond to errors of 14.4 percent, 24.6 percent, and 17.8 percent. As with the intensity estimation algorithm, there is a tendency toward over (under) estimation of small (large) azimuthally averaged wind radii by the AMSU. Additionally, the wind radii estimates in the NE, SE, SW, and NW quadrants capture the asymmetric structure well, generally comparing favorably with the NHC operational advisory estimates. In some cases, the AMSU estimates may even be superior to NHC estimates, especially in the Eastern Pacific. Finally, the 1999 and 2000 AMSU data are combined to refine the TC intensity and azimuthally averaged wind radii estimation algorithms. The two-year based algorithms currently are being tested on AMSU data received from the Atlantic and East Pacific basins during the 2001 tropical season.Funding for this research is supplied in part by an American Meteorological Society Graduate Student Fellowship, sponsored by GTE Government Systems, and also by the United States Weather Research Program, NOAA grant NA67RJ0152

Identification of the connections in biologically inspired neural networks

We developed an identification method to find the strength of the connections between neurons from their behavior in small biologically-inspired artificial neural networks. That is, given the network external inputs and the temporal firing pattern of the neurons, we can calculate a solution for the strengths of the connections between neurons and the initial neuron activations if a solution exists. The method determines directly if there is a solution to a particular neural network problem. No training of the network is required. It should be noted that this is a first pass at the solution of a difficult problem. The neuron and network models chosen are related to biology but do not contain all of its complexities, some of which we hope to add to the model in future work. A variety of new results have been obtained. First, the method has been tailored to produce connection weight matrix solutions for networks with important features of biological neural (bioneural) networks. Second, a computationally efficient method of finding a robust central solution has been developed. This later method also enables us to find the most consistent solution in the presence of noisy data. Prospects of applying our method to identify bioneural network connections are exciting because such connections are almost impossible to measure in the laboratory. Knowledge of such connections would facilitate an understanding of bioneural networks and would allow the construction of the electronic counterparts of bioneural networks on very large scale integrated (VLSI) circuits

Online-Informationssystem für die Phytotherapie bei Tieren

Die Phytotherapie gewinnt auch in der Veterinärmedizin zunehmend an Beliebtheit. Um das therapeutische Potenzial der Arzneipflanzen auszuschöpfen und deren sicheren Einsatz zu gewährleisten, bedarf es aber besonderer Kenntnisse der wirksamen Pflanzenteile beziehungsweise Zubereitungen. Unsachgemässe Anwendungen und Überdosierungen von Arzneipflanzen können toxisch sein. Deshalb haben wir mit www.phytoarznei.ch eine Entscheidungshilfe geschaffen, die online einen raschen Zugriff auf das aktuelle Wissen zu Arzneipflanzen und deren Gebrauch bei Tieren erlaubt. Dieses ­Informationssystem basiert auf der verfügbaren Fach­literatur, die nach kritischer Auswertung in eine strukturierte Datenbank eingebracht wurde. Für jede Arz­neipflanze beziehungsweise pflanzliche Droge sind therapeutische Indikationen, Anwendungsarten, organoleptische Eigenschaften, Inhaltsstoffe, pharmakologische Wirkungen, Dosierungen, Behandlungsdauer, Toxizität, gesetzliche Vorschriften bei Nutztieren sowie Dopingrelevanz aufgeführt. Zwei Suchprogramme gewährleisten einen benutzerfreundlichen Zugang, entweder durch die Eingabe des Pflanzennamens, des Drogennamens bzw. der Inhaltsstoffe der Pflanze in einem Suchfeld oder durch die Auswahl der gewünschten Tierspezies sowie therapeutischen Anwendung aus entsprechenden Dropdown-Listen. Diese Datenbank zu Arzneipflanzen ist mit der Giftpflanzendatenbank der Universität Zürich und, falls entsprechende Fertigpräparate vorliegen, mit dem Schweizerischen Tierarzneimittelkompendium sowie einem Verzeichnis von Veterinärprodukten verknüpft

Report of the Task Force on International Assistance for Strengthening National Agricultural Research

Report of a task force established by decision of the CGIAR in September 1977 to study what should be done to strengthen agricultural research capacity in developing countries. The task force consisted of donor representatives, and representatives of developing country agricultural research institution. The report was transmitted to the CGIAR by its chairman, Richard H. Demuth. It recommends establishment of an International Service for National Agricultural Research (ISNAR) under CGIAR auspices. The report makes recommendations with respect to the functions, financing, operations, governance, and location of the proposed service. This is a 40 page document, with eight annexes, including an exchange with the Director General of FAO about the possibility of that organization performing the functions proposed for ISNAR. The report was presented orally to a joint meeting of TAC and center directors in June 1978, and was an agenda document at the TAC Twentieth Meeting in September 1978 and the CGIAR meeting November 1978

Coverage-dependent adsorption sites in the K/Ru(0001) system: a low-energy electron-diffraction analysis

The two ordered phases p(2 × 2) at a coverage θ = 0.25 and (√3 × √3)R30° at θ = 0.33 of potassium adsorbed on Ru(0001) were analyzed by use of low-energy electron-diffraction (LEED). In the (√3 × √3)R30° phase, the K atoms occupy threefold hcp sites, while in the p(2 × 2) phase the fcc site is favoured. In both phases, the K hard-sphere radii are nearly the same and close to the covalent Pauling radius

Simplicity of extremal eigenvalues of the Klein-Gordon equation

We consider the spectral problem associated with the Klein-Gordon equation for unbounded electric potentials. If the spectrum of this problem is contained in two disjoint real intervals and the two inner boundary points are eigenvalues, we show that these extremal eigenvalues are simple and possess strictly positive eigenfunctions. Examples of electric potentials satisfying these assumptions are given

The structure ofAl(111)-K−(√3 × √3)R30° determined by LEED: stable and metastable adsorption sites

It is found that the adsorption of potassium on Al(111) at 90 K and at 300 K both result in a (√3 × √3)R0° structure. Through a detailed LEED analysis it is revealed that at 300 K the adatoms occupy substitutional sites and at 90 K the adatoms occupy on-top sites; both geometries have hitherto been considered as very unusual. The relationship between bond length and coordination is discussed with respect to the present results, and with respect to other quantitative studies of alkali-metal/metal adsorption systems

Design of (ω-N-(O-acyl)hydroxy amid) aminodicarboxylic acid pyrrolidides as potent inhibitors of proline-specific peptidases

AbstractA novel class of competitive, acylating inhibitors for the proline-specific peptidases: dipeptidyl peptidase IV, dipeptidyl peptidase II and prolyl endopeptidase, has been developed. The inhibitor molecules combine the efficacy of aminoacyl pyrrolidides and the potential transacylating capability of diacyl hydroxyl amines. The N-terminal deblocked inhibitors are potent reversible inhibitors of porcine kidney dipeptidyl peptidase IV, human placenta dipeptidyl peptidase II exhibiting K1 values in the μM range. Boc-protected (ω-N-hydroxy acyl amid) aminodiacarboxylic acid pyrrolidides inhibit substrate hydrolysis by prolyl endopeptidases from different sources competitively reaching K, values of 30 nM to 60 μM. Additionally, α-N-BOC-(ω-N-hydroxy acetyl) glutaminyl pyrrolidide modifies human placenta prolyl endopeptidase in a time-dependent reaction

Multilingual assessment of early child development: Analyses from repeated observations of children in Kenya.

In many low- and middle-income countries, young children learn a mother tongue or indigenous language at home before entering the formal education system where they will need to understand and speak a countrys official language(s). Thus, assessments of children before school age, conducted in a nations official language, may not fully reflect a childs development, underscoring the importance of test translation and adaptation. To examine differences in vocabulary development by language of assessment, we adapted and validated instruments to measure developmental outcomes, including expressive and receptive vocabulary. We assessed 505 2-to-6-year-old children in rural communities in Western Kenya with comparable vocabulary tests in three languages: Luo (the local language or mother tongue), Swahili, and English (official languages) at two time points, 5-6 weeks apart, between September 2015 and October 2016. Younger children responded to the expressive vocabulary measure exclusively in Luo (44%-59% of 2-to-4-year-olds) much more frequently than did older children (20%-21% of 5-to-6-year-olds). Baseline receptive vocabulary scores in Luo (β = 0.26, SE = 0.05, p < 0.001) and Swahili (β = 0.10, SE = 0.05, p = 0.032) were strongly associated with receptive vocabulary in English at follow-up, even after controlling for English vocabulary at baseline. Parental Luo literacy at baseline (β = 0.11, SE = 0.05, p = 0.045) was associated with child English vocabulary at follow-up, while parental English literacy at baseline was not. Our findings suggest that multilingual testing is essential to understanding the developmental environment and cognitive growth of multilingual children