170,053 research outputs found
Effects of Wrack Burial in Salt-Stressed Habitats: Batis Maritima in a Southwest Atlantic Salt Marsh
No full textIn coastal salt marshes, mats of wrack (dead plant stems) that are deposited on the marsh by high tides can kill underlying vegetation and initiate secondary succession. The importance of wrack disturbance in northwest Atlantic salt marshes has been a topic of recent debate. The importance of wrack disturbance in southwest Atlantic salt marshes, which experience a very different climate regime than do northern marshes, has rarely been examined. Working in a Georgia salt marsh, we documented a pattern of positive association between wrack and Batis maritima biomass, and conducted experiments that indicated that wrack was beneficial to Batis maritima. Sampling indicated that natural wrack deposition was correlated with areas of vigorous Batis growth and mild soil conditions. Natural wrack deposition occurred primarily at the highest elevations occupied by Batis maritima (the high Batis zone). Batis plants in the high zone were taller, with more and larger leaves, and contained several times the biomass/unit area than Batis plants at lower elevations. High zone soils had lower salinities, better percolation rates, and a lower organic content than did soils from lower elevations. Experimental manipulations demonstrated that deposition of wrack was partially responsible for these patterns. In each of two experiments, soil salinities were lower and plants taller and larger in the presence of wrack compared to in its absence. Although wrack lowered salinities and enhanced plant growth, the effects were not large enough to completely explain the differences between Batis zones. Instead, wrack probably reinforced pre-existing gradients in flooding and salinity caused by differences in elevation and terrestrial runoff. Our results contrast with previous studies from northern marshes. Because of geographic differences in climate and plant phenology, northern marshes are more likely than southern marshes to receive patches of wrack thick enough to kill underlying vegetation. Plants covered by thin layers of wrack, as commonly occurs in southern marshes, may often grow through the wrack rather than suffer mortality. Also because of climatic differences, wrack is more likely to benefit plants by ameliorating salinity stress in southern marshes, where soil salinities are often hypersaline, than in northern marshes where soils are rarely hypersaline. Although ecological processes may differ between northern and southern salt marshes, these differences may be predictable based on an understanding of geographic variation in climate
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Presidents of three Ardmore banks, c!970.
No full textPresidents of three Ardmore banks, c!970. (left to right) Bill Grissom, Lincoln Bank, Ford Simmons, Exchange Natl. Bank, and Robert Batis, First Natl. Bank
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Investigations of cultivar differences for uptake and utilization of nitrogen in winter wheat (Triticum aestivum L., cv. Batis and cv. Toronto)
No full textDie Winterweizensorten Batis und Toronto zeigten in mehrjährigen Feldversuchen regelmäßige Sortenunterschiede in der Aufnahme und Verwertung von Stickstoff. Dabei traten auch signifikante Wechselwirkungen Sorte x N-Düngung auf, die mit einfachen Annahmen zur negativen Beziehung zwischen Kornertrag und Kornprotein-Konzentration von Winterweizen nicht übereinstimmen. Ziel der vorliegenden Arbeit war es, Einblicke in die möglichen Ursachen der sortenbedingten Unterschiede zwischen Batis und Toronto zu gewinnen. Im Mittelpunkt der Untersuchungen stand die Aufklärung der während der Jugendentwicklung feststellbaren Unterschiede in der N-Konzentration der oberirdischen Biomasse und der Auswirkungen einer unterschiedlichen Handhabung der N-Düngung, insbesondere der N-Spätdüngung, im weiteren Vegetationsverlauf. Einen weiteren Schwerpunkt bildete die Untersuchung der sortenbedingten Abstufungen in der Ertragsstruktur, die sich unter dem Einfluss eines differenzierten N-Angebotes entwickelten. In einem zweijährigen Feldversuch wurden deshalb die Sorten Batis und Toronto in Abhängigkeit einer nach Menge und Applikationszeitpunkt variierten mineralischen N-Düngung geprüft. Das N-Angebot variierte von 60 bis 240 kg/ha N und wurde in bis zu vier Teilgaben (VB, EC 30, EC 32, EC 49) ausgebracht. Darüber hinaus waren ungedüngte Kontrollparzellen in den Versuch integriert. Zur Beschreibung der Ertragsbildung erfolgten zu insgesamt acht Terminen Zwischenernten der oberirdischen Biomasse und neben dem Verlauf der Trockenmassebildung und der Entwicklung der Pflanzen- und Triebzahlen, wurde die Aufnahme und Assimilation von N sowie dessen Verwertung untersucht. Hierzu wurden charakteristische Merkmale des C/N-Stoffwechsels bestimmt und in den Pflanzenproben die Gehalte an N, Nitrat-N, wasserlöslichen Kohlenhydraten sowie die Aktivität an Nitratreduktase ermittelt. Die Ertragsermittlung erfolgte anhand von Parzellenerträgen und mittels Ertragsstrukturanalyse von Einzelpflanzen. Bereits im Jugendstadium zeigten sich signifikante Sortenunterschiede in der N-Konzentration der oberirdischen Biomasse, denen hauptsächlich Differenzierungen im Aneignungsvermögen des in der Bodenlösung verfügbaren Nitrat-N zu Grunde lagen. Toronto wies eine deutlich höhere Nitratreduktaseaktivität während der Jugendentwicklung auf und war in der Lage, den während der Bestockungsphase pflanzenverfügbaren N schneller als Batis zu assimilieren. Als Sink für den zusätzlich aufgenommenen N diente Toronto vor allem eine ansteigende Nebentriebbildung. Im weiteren Vegetationsverlauf konnten Sortenunterschiede in der N-Akkumulation vor allem bei hoher N-Düngung festgestellt werden, die auf zunehmend geringerer N-Ausnutzung des pflanzenverfügbaren N-Angebotes durch Batis beruhte. Bei geringer und mittlerer N-Versorgung zeigten sich dagegen kaum Unterschiede in der N-Aufnahme, da die höhere N-Konzentration von Toronto durch zunehmend ähnlichen Verlauf der Biomassebildung beider Sorten maskiert wurde. Für die Sortenunterschiede im Korn-N-Ertrag waren neben Unterschieden in der N-Aufnahme auch Differenzierungen in der Mobilisation von vorblütlichem N aus der vegetativen Biomasse verantwortlich. Die Variation in der Gesamt-N-Aufnahme beider Sorten beruhte vor allem auf Differenzierungen der N-Einlagerung ins Korn, während die Variation der Stroh-N-Masse deutlich geringer ausfiel. Mit Verringerung des N-Angebotes nahm die Bedeutung sortenbedingter Unterschiede im Kornertrag zu und überlagerte schließlich bei fehlender ergänzender N-Düngung die Differenzierungen in der N-Konzentration des Korns. Die regelmäßig angedeuteten höheren N-Entzüge von Batis unter stark limitiertem N-Angebot beruhten vor allem auf diesem Effekt. Auf die sortenspezifische Ausbildung der Ertragsstruktur wirkte sich insbesondere die Handhabung der N-Düngung in frühen Vegetationsstadien aus. Hierbei zeigte sich, dass bei Toronto in höherem Maße als bei Batis Kompensationsmechanismen zwischen Start- und Schossergabe wirksam waren. Differenzierungen in den Reduktionsprozessen von Ertragsorganen waren dagegen gegenüber düngungsabhängigen Unterschieden in der Organanlage von untergeordneter Bedeutung. Die höheren Kornertragsleistungen von Batis bei limitiertem N-Angebot beruhten vor allem auf hoher Tausendkornmasse, während für die Sortendifferenzierungen bei höherer N-Düngung die Kornzahl je Fläche zunehmende Bedeutung erlangte. Unter sehr günstigen Bedingungen während der Abreife hat Toronto trotz absinkender Tausendkornmasse bei ausreichend hoher N-Versorgung damit ähnliche Ertragsleistungen wie Batis erzielt. Die Ergebnisse dieser Arbeit zeigen, dass die feststellbaren Sortenunterschiede in der N-Verwertung während später Vegetationsphasen noch ergänzende Untersuchungen zu den Mechanismen der sortenunterschiedlichen Verwertung der N-Spätdüngung erfordern, bevor hieraus potenziell wichtige Schlussfolgerungen für eine systematische Verbesserung der N-Effizienz in der Weizenzüchtung gezogen werden können.During a previous field trial series significant differences for uptake and utilization of nitrogen fertilizer were observed between winter wheat cultivars Batis and Toronto. Significant cultivar x fertilizer interactions occurred which disagree with simple assumptions of negative relations between grain yield and grain protein concentration. The overall objective of this study was to examine possible causes of cultivar differences between Batis and Toronto. The primary objective of this study was to classify the basis of cultivar differences in biomass nitrogen concentrations during early growth stages and cultivar response to different nitrogen applications especially in later plant development stages. A secondary objective was to explore cultivar specific differences in yield components that were observed in response to nitrogen application. Winter wheat cultivars Batis and Toronto were tested in a two-year field trial under ten nitrogen regimes, varying in rate (0, 60, 120, 180, 240 kg/ha N) and timing of nitrogen application (early spring, EC 30, EC 32, EC 49). Canopy biomass, stand density, and N-uptake have been determined eight times prior to harvest. In addition to total N-uptake content of nitrate, soluble carbohydrates concentration and nitrate reductase activity. Total grain yield and yield components were assessed from plot wide harvests and individual plant measurements. During the early stages of development, significant differences between cultivars were observed for nitrogen concentrations and canopy biomass. The differences observed indicate cultivar differentiation in the ability to acquire available soil nitrogen. Cv. Toronto exhibited significantly higher nitrate reductase activity during early growth stages and higher assimilation of available nitrogen during tillering. Increase in number of tillers may represent the sink for increased nitrogen uptake of cv. Toronto. Cultivar differences in nitrogen uptake into the canopy also occurred during later development stages, especially with higher doses of nitrogen fertilization, indicating a decrease in utilization of plant available nitrogen by cv. Batis. At low and medium levels of nitrogen application only slight differences in nitrogen uptake were observed because higher biomass nitrogen concentration of cv. Toronto was masked by similar growth rates of canopy biomass for both cultivars. Distinct cultivar differences in grain nitrogen content were based on differences in mobilization of preanthesis nitrogen in addition to continuing differences in postanthesis nitrogen uptake. Variation of canopy nitrogen uptake related mainly to differences in grain nitrogen, while variation of straw nitrogen content was of minor importance. With lower nitrogen doses cultivar differences in grain yield increased, and finally surpassed differences in grain nitrogen concentration in regimes without nitrogen fertilization. Higher levels of nitrogen accumulation of cv. Batis under conditions of limited nitrogen availability are closely associated with this effect. Cultivar specific differences in yield structure were subjected to modifications in early growth stages. Compensation mechanisms between nitrogen application at early spring and at shooting stage were more effective in cv. Toronto than in cv. Batis. Differences in the reduction processes were of minor importance as compared to cultivar differences in the initiation of yield organs. Higher grain yields of cv. Batis under conditions of limited nitrogen application were mainly caused by high 1000 kernel weight, while differences between cultivars in the number of kernel per area favored cv. Toronto and were more important at higher nitrogen doses. With favourable conditions during grain filling cv. Toronto reached similar levels of yield as cv. Batis; inspite of lower 1000 kernel weight associated with high nitrogen application. In conclusion, the results obtained that cultivar differences in nitrogen utilization during later plant development stages need further investigations on mechanism of cultivar specific regulations in utilization of late nitrogen application, since potentially important implications may be derived for systematic improvements of nitrogen efficiency in wheat breeding
An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post
No full textAn article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp
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