bluuebunny/crossref_metadata_2025 huggingface dataset:
Psidium guvajava L Leaf Powder — A Potential Low-cost Biosorbent for the Removal of Cadmium(II) Ions from Wastewater
Authors: Rao K.S. , Anand S. , Venkateswarlu P.
Published: October 2010

In the present investigation, an evaluation has been made of the adsorption of Cd(II) ions onto Psidium guvajava L leaf powder (PGL). Scanning electron micrographs of the powder as-prepared showed that PGL possessed an irregular texture consisting of globular and elongated grains. The porosity of the structure was also noted. After adsorption of Cd(II) ions, ca. 30% of the powdered grains on the resulting surface showed a pixel concentration of Cd(II) ions, indicating the adsorption of Cd(II) ions by selective grains. The FT-IR spectra of the as-prepared powder and the Cd(II) ion-loaded powder were similar but the absorption bands were shifted by 5–35 cm−1 after the adsorption process. The experimental parameters chosen for adsorption studies included time, pH, particle size, temperature, adsorbate, biosorbent, anions and Pb(II) ion concentrations.

The kinetic data followed linear and non-linear pseudo-second-order kinetics. The adsorption of Cd(II) ions increased from zero to 60.39% as the pH of the aqueous solution was increased from 2 to 3.5, with a further increase in pH to 5.5 resulting in a marginal increase in the extent of adsorption to 63.7%. The isothermal data were well fitted by the Freundlich adsorption model. On the basis of the Langmuir isotherm model, the maximum loading capacity was calculated as 31.15 mg/g. The presence of chloride or sulphate anions had an adverse effect on the Cd(II) ion uptake by PGL. Lead(II) ions were adsorbed preferentially from binary Cd(II)/Pb(II) ion solutions, thereby decreasing the Cd(II) ion uptake. The thermodynamic parameters for the process were also estimated.
Investments and Energy Efficiency in Colombian Manufacturing Industries
Authors: Martínez Clara Inés Pardo
Published: October 2010

This paper investigates the effects of investments on energy efficiency performance using data from Colombian manufacturing industries. These industries were analysed as a whole and as energy intensive sectors and non-energy intensive sectors between 1998 and 2005. Using a simple factor demand model, we estimate the structural parameters of the model using both time-series and cross-sectional dimensions of the data, and we include the effect that investments have on energy efficiency in Colombian manufacturing industries. The results showed that in Colombian manufacturing industries overall, as well as in non-energy intensive sectors, the main variables that determine energy efficiency performance are energy prices, machinery and equipment investments and foreign investments. Whereas electricity prices show lower significance levels, investments in research and development (R&D) are not statistically significant. In contrast, for energy intensive sectors, only energy prices and foreign investments are statistically significant. Therefore, these results demonstrate the close relationship between energy prices and investments with respect to energy efficiency improvements in Colombian manufacturing industries. These findings have important implications for policy makers aiming to encourage governments to adopt strategies that combine energy prices and technological change, as well as those policy makers wishing to strengthen foreign investment in order to improve technology development, productivity and energy efficiency in manufacturing industries.
Wood Charcoal Supply to Addis Ababa City and its Effect on the Environment
Authors: Alem Shiferaw , Duraisamy Jeevanandhan , Legesse Eyerusalem , Seboka Yishak , Mitiku Eyerusalem
Published: October 2010

Charcoal is a major source of energy for cooking, heating and lightening in sub-Saharan African countries. The livelihood of many rural and urban people also depends on the proceeds obtained from the sell of charcoal. Thus this, study was conducted with the objective to quantify the amount of charcoal supplied to Addis Ababa city, the capital of Ethiopia and its means of transportation. It is a result of a one week follow up study on the inlet of charcoal into the city. The data was analyzed using descriptive statistics and SAS software. The result indicated that about 7,549 different sizes and weights of bags of charcoal were supplied to the city in a day, suggesting an equivalent of about 68,886 tones of charcoal per year and about 899, 818 trees to being cut to this supply, releasing about 125,717 – 167,623 tones of carbon to the atmosphere. About 35% of the total charcoal flowing into the city enters in the morning between 6:00 a.m. and 11:59 a.m. While, about 34%, 21% and 10% enters the city in the afternoon, during the night and evening, respectively. Of the 9,822 vehicles encountered, entering in to the city in a day, about 2,148 of them were coming with loads of charcoal, Isuzus and heavy Trucks such as tank Truck, daf Tractor, Mercedes-Benz Truck etc. being the major ones. The finding of the study also indicated, the high dependency of the city on charcoal as an energy source, negatively affecting the environment.
A Materials Scientist Ponders Global Warming/Cooling
Authors: Kelly Anthony
Published: October 2010

Eminent climatologists support the opinion of the Intergovernmental Panel on Climate Change (IPCC) that rising global average temperature is due to anthropogenic CO2 emissions. A number dispute this. This paper is written by a physical scientist aiming to understand the controversy for himself. An elementary account is given of the physical theory of the Earth's average temperature so as to introduce the principal parameters: solar irradiance; earth's albedo; physics of the factors determining the emissivity of the earth. The rise in mean global temperature observed intermittently over the last one hundred years has markedly slowed over the last ten. This discrepancy with the prediction of accepted models of a secular change of climate, coupled with the known uncertainties concerning the effects of clouds and of water vapour cast doubt on the accuracy of the models. The lead position of CO2 in forcing a change of climate is hence questioned. The apparent neglect of man-made changes in the distribution of water is emphasised. The uncertainties regarding the behaviour of water vapour and cloudiness must be resolved if the cited causes of any climate change are to be fully reliable.
Large-Scale Simulations for Turbine Engine Core Noise
Authors: Van Zante Dale
Published: October 2010

As turbofan engine bypass ratios continue to increase, the contribution of the turbine to the engine and aircraft noise signature is receiving more attention. Understanding the relative importance of the various turbine noise generation mechanisms and the characteristics of the turbine acoustic transmission loss are essential ingredients in developing robust reduced-order models for predicting the turbine noise signature. A computationally based investigation has been undertaken to help guide the development of a turbine noise prediction capability that does not rely on empiricism. Under the auspices of the Fundamental Aeronautics Program, NASA is currently funding core noise research focused on the generation and propagation mechanisms of combustor and turbine noise in the combustor-turbine-nozzle system. Highly detailed numerical simulations of the unsteady flow field inside the first stage of a modern high-pressure turbine were carried out using TURBO. Spectral and modal analysis of the unsteady pressure data from the numerical simulation of the turbine stage show a circumferential modal distribution that is consistent with the Tyler-Sofrin rule, which gives confidence in the approach. Additionally, initial steps have been taken in determining the source strength hierarchy.
The Effect of Approach on Spike Jump Height for Female Volleyball Players
Authors: Hsieh ChengTu , Christiansen Cory L.
Published: October 2010

The purpose of the study was to compare vertical jump height using a four-step approach volleyball spike jump (VBSJ) and a standing counter-movement jump (CMJ) for competitive female volleyball players. Ten NCAA Division I female volleyball players were recruited. Each participant performed jumps using two techniques: a four-step approach VBSJ and a standing CMJ. Mean jump height for the VBSJ (0.38 ± 0.06 m) was significantly greater than the CMJ (0.33 ± 0.05 m). No correlation between jump height and horizontal center of mass (CoM) velocity during the VBSJ approach was found. The results indicate that a four-step approach benefits jump height for elite female volleyball players. However, approach velocity is not a determining factor that makes a four-step approach more beneficial. Other characteristics, such as improved force development and power production may better explain the benefit of the VBSJ approach for female volleyball players.
The Application of Coach Leadership Models to Coaching Practice: Current State and Future Directions
Authors: Vella Stewart A. , Oades Lindsay G. , Crowe Trevor P.
Published: October 2010

The purpose of this concept/review article is to critically discuss the application of sports coaching leadership models to coaching practice. The focus of the discussion will be on the coherence and impact of the numerous models in the current literature, and the accumulated impact that they have on practitioners. This discussion will be framed in current conceptions of sports coaching and expected athlete outcomes. This article can serve an important role in the continuing dialogue about the essence of sports leadership; particularly in relation to how it is defined, how it is measured, and how the leadership literature can be applied in the field.
Effects of the Burner Diameter on the Flame Structure and Extinction Limit of Counterflow Non-Premixed Flames
Authors: Oh Chang Bo , Lee Eui Ju , Park Jeong
Published: October 2010

Experiments and numerical simulations were conducted to investigate the effects of the burner diameter on the flame structure and extinction limit of counterflow non-premixed methane flames in normal gravity and microgravity. Experiments were performed for counterflow flames with a large inner diameter ( d) of 50 mm in normal gravity to compare the extinction limits with those obtained by previous studies where a small burner ( d < 25 mm) was used. Two-dimensional (2D) simulations were performed to clarify the flame structure and extinction limits of counterflow non-premixed flame with a three-step global reaction mechanism. One-dimensional (1D) simulations were also performed with the same three-step global reaction mechanism to provide reference data for the 2D simulation and experiment. For microgravity, the effect of the burner diameter on the flame location at the centerline was negligible at both high ( ag = 50 s−1) and low ( ag = 10 s−1) strain rates. However, a small burner flame ( d = 15 mm) in microgravity showed large differences in the maximum flame temperature and the flame size in radial direction compared to a large burner flame ( d = 50 mm) at low strain rate. In addition, for normal gravity, a small burner flame ( d = 23.4 mm) showed differences in the flame thickness, flame location, local strain rate, and maximum heat release rate compared to a large burner flame ( d = 50 mm) at low strain rate. Counterflow non-premixed flames with low and high strain rates that were established in a large burner were approximated by 1D simulation for normal gravity and microgravity. However, a counterflow non-premixed flame with a low strain rate in a small burner could not be approximated by 1D simulation for normal gravity due to buoyancy effects. The 2D simulations of the extinction limits correlated well with experiments for small and large burner flames. For microgravity, the extinction limit of a small burner flame ( d = 15 mm) was much lower than that of a large burner flame when ag ≤ 20 s−1. For normal gravity, the extinction limit of a small burner flame ( d = 23.4 mm) was also much lower than that of the large burner flame when ag ≤ 35 s−1. The effects of the burner diameter on the flame structure and extinction limit of counterflow non-premixed methane flames were more important in normal gravity than in microgravity.
Indirect Combustion Noise: Noise Generation by Accelerated Vorticity in a Nozzle Flow
Authors: Kings Nancy , Bake Friedrich
Published: October 2010

The noise generation by accelerated vorticity waves in a nozzle flow was investigated in a model experiment. This noise generation mechanism belongs, besides entropy noise, to the indirect combustion noise phenomena. Vorticity as well as entropy fluctuations, originating from the highly turbulent combustion zone, are convected with the flow and produce noise during their acceleration in the outlet nozzle of the combustion chamber. In the model experiment, noise generation of accelerated vorticity fluctuations was achieved. The vorticity fluctuations in the tube flow were produced by injecting temporally additional air into the mean flow. As the next step, a parametric study was conducted to determine the major dependencies of the so called vortex noise. A quadratic dependency of the vortex noise on the injected air amount was found. In order to visualise and classify the artificially generated vorticity structures, planar velocity measurements have been conducted applying Particle Image Velocimetry (PIV).
Dynamic Characterization of Candle Flame
Authors: Ghosh Suvojit , Mondal Sirshendu , Mondal Tanmoy , Mukhopadhyay Achintya , Sen Swarnendu
Published: October 2010

The present work focuses on studying the flickering of a candle placed in a hollow cylindrical glass tube. Variations in flame area and intensity have been studied as the oscillating parameters of the flame with a camera and a Photomultiplier tube (PMT), and results have been found to be indicative of the presence of some well defined peaks in the amplitude spectrum of the flame intensity. Tests have been carried out with a range of candle diameters for the same glass tube giving similar results. Fluctuations in fractal dimension of the flame structure have also been studied in the course of the work. The time series data generated by processing camera images and also the PMT voltage output has been studied for existence of periodicity in the signal recorded. The correlation dimension has been determined for a number of experiments to characterize the dynamics of the signal.
Mechanism of translational regulation by miR-2 from sites in the 5′ untranslated region or the open reading frame
Authors: Moretti Francesca , Thermann Rolf , Hentze Matthias W.
Published: October 2010

MicroRNAs (miRs) commonly regulate translation from target mRNA 3′ untranslated regions (UTRs). While effective miR-binding sites have also been identified in 5′ untranslated regions (UTRs) or open reading frames (ORFs), the mechanism(s) of miR-mediated regulation from these sites has not been defined. Here, we systematically investigate how the position of miR-binding sites influences translational regulation and characterize their mechanistic basis. We show that specific translational regulation is elicited in vitro and in vivo not only from the 3′UTR, but equally effectively from six Drosophila miR-2-binding sites in the 5′UTR or the ORF. In all cases, miR-2 triggers mRNA deadenylation and inhibits translation initiation in a cap-dependent fashion. In contrast, single or dual miR-2-binding sites in the 5′UTR or the ORF yield rather inefficient or no regulation. This work represents the first demonstration that 5′UTR and ORF miR-binding sites can function mechanistically similarly to the intensively investigated 3′UTR sites. Using single or dual binding sites, it also reveals a biological rationale for the high prevalence of miR regulatory sites in the 3′UTR.
Nitric oxide stimulates human sperm motility via activation of the cyclic GMP/protein kinase G signaling pathway
Authors: Miraglia Erica , De Angelis Federico , Gazzano Elena , Hassanpour Hossain , Bertagna Angela , Aldieri Elisabetta , Revelli Alberto , Ghigo Dario
Published: October 2010

Nitric oxide (NO), a modulator of several physiological processes, is involved in different human sperm functions. We have investigated whether NO may stimulate the motility of human spermatozoa via activation of the soluble guanylate cyclase (sGC)/cGMP pathway. Sperm samples obtained by masturbation from 70 normozoospermic patients were processed by the swim-up technique. The kinetic parameters of the motile sperm-rich fractions were assessed by computer-assisted sperm analysis. After a 30–90 min incubation, the NO donorS-nitrosoglutathione (GSNO) exerted a significant enhancing effect on progressive motility (77, 78, and 78% vs 66, 65, and 62% of the control at the corresponding time), straight linear velocity (44, 49, and 48 μm/s vs 34, 35, and 35.5 μm/s), curvilinear velocity (81, 83, and 84 μm/s vs 68 μm/s), and average path velocity (52, 57, and 54 μm/s vs 40, 42, and 42 μm/s) at 5 μM but not at lower concentrations, and in parallel increased the synthesis of cGMP. A similar effect was obtained with the NO donor spermine NONOate after 30 and 60 min. The GSNO-induced effects on sperm motility were abolished by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (a specific sGC inhibitor) and mimicked by 8-bromo-cGMP (8-Br-cGMP; a cell-permeating cGMP analog); the treatment with Rp-8-Br-cGMPS (an inhibitor of cGMP-dependent protein kinases) prevented both the GSNO- and the 8-Br-cGMP-induced responses. On the contrary, we did not observe any effect of the cGMP/PRKG1 (PKG) pathway modulators on the onset of hyperactivated sperm motility. Our results suggest that NO stimulates human sperm motility via the activation of sGC, the subsequent synthesis of cGMP, and the activation of cGMP-dependent protein kinases.
A nyitott, feszülésmentes, illetve feszülés mellett végzett lágyéksérvműtét hosszú távú eredményei – retrospektív vizsgálat
Authors: Baracs József , Huszár Orsolya , Gadácsi Melinda , Horváth Örs Péter , Wéber György
Published: October 2010

Absztrakt

A szerzők ismertetik a 2004-ben a Pécsi Tudományegyetem Sebészeti Klinikáján lágyéksérv miatt operált összes beteg hosszú távú utánkövetési eredményeit. Az értékelés során a feszülésmentes és a feszülés mellett végzett, nyitott herniotomiákat vetjük össze a betegek kérdőívre adott válasza alapján. Eredmények: Eredményeinket 155 beteg adatainak elemzése alapján közöljük. Recidívaarány hálóval (H) 3,4% (4/116), háló nélkül (HN) 12,8% (5/39). Teljesen panaszmentes a betegek 83 (97/116 – H), illetve 89%-a (35/39 – HN). Jelentős krónikus fájdalom 1,7% (2/116 – H), illetve 7,7% (3/39 – HN). Korai aktivitás elérése 34% (39/116 – H), illetve 29% (11/39 – HN). Következtetés: Vizsgálatunk igazolta, hogy Lichtenstein-műtét után alacsonyabb a recidíva, azonban a krónikus fájdalom, illetve az aktivitás visszanyerésének tekintetében vizsgálatunk nem talált lényeges különbséget a feszülésmentes és a feszülés mellett végzett, nyitott herniotomia között.
Kedvezőbb műtéti eredmények „onlay” hálóval, mint „sublay” helyzetben beültetettel
Authors: Wéber György , Baracs József , Horváth Örs Péter
Published: October 2010

Absztrakt

Bevezetés:A hasfal rekonstrukciójára számos műtéti megoldás ismert, az eredmények azonban meglehetősen szerények és ellentmondásosak. Vizsgálatunk célja a hasfali sérvek varrattal, illetve hálóbeültetéssel végzett műtéti kezelésének valamint az onlay, illetve sublay helyzetben beültetett hálók műtéti eredményeinek összehasonlítása.Anyag és módszerek:A 2002-ben kezdődött multicentrikus, prospektív, randomizált vizsgálatban az ország 20 sebészeti osztályán (lásd Függelék) 953 beteg hasfali rekonstrukcióját végeztük el. A betegeket, a sérv nagysága szerint két csoportba osztottuk: A csoport (n= 494): a sérvkapu nagysága 5–25 cm2(kis sérv) és B csoport (n= 459): a sérvkapu nagyobb, mint 25 cm2(nagy sérv). A randomizálásnak megfelelően az A csoportban a hasfal-rekonstrukció varrattal (n= 247), illetve hálóbeültetéssel (sublayn= 247) történt. A 25 cm2-nél nagyobb sérvek esetében (B csoport) hálóbeültetés történt, random módon sublay (n= 235), illetve onlay technikával (n= 224). Az utánkövetés öt évig tartott, és 2009 márciusában fejeződött be.Eredmények:Az ötéves utánkövetés során 219 beteget zártunk ki a vizsgálatból, így 734 beteg (a randomizált betegek 77%-a) adatait tudtuk elemezni. Az A csoport varrattal kezelt 184 betegénél 50 esetben (27%), míg a hálóval kezelt 180 betegénél 15 esetben (8%) találtunk recidív sérvet, a különbség szignifikáns (p< 0,001). A nagy sérvek eseté-ben (B csoport) a 189 sublay meshnél 38 esetben (20%), míg a 181 onlay meshnél 22 esetben (12%) találtunk recidív sérvet, a különbség ugyancsak szignifikáns (p< 0,05).Következtetések:A hálóbeültetés jobb, mint a varrattal történő hasfal-rekonstrukció. A 25 cm2-nél nagyobb sérvek esetében – a szakmai vélekedéssel ellentétben – az „onlay” hálóval szignifikánsan jobbak a műtéti eredmények, mint a „sublay” helyzetben beültetett hálóval.

A randomizált vizsgálat ID száma NCT01018524 (www.ClinicalTrials.gov).
A lágyéktáji és hasfali sérvek laparoscopos műtétei – áttekintés
Authors: Bátorfi József
Published: October 2010

Absztrakt

A közlemény áttekinti a laparoscopos sérvsebészet történetét, a lágyéktáji és ventralis sérvek laparoscopos megoldásait, technikáját, eredményeit. Az előnyök és hátrányok mérlegelése alapján megállapítja, hogy a laparoscopos sérvműtétek kiváló eredményekkel járnak a korai rehabilitáció, a közvetlen és távoli posztoperatív fájdalom, valamint az igen alacsony (kevesebb mint 1, illetve 5%) recidívaarány vonatkozásában. Gyakorlott sebész kezében méltán tekinthetők a sérvműtétek gold standardjének.
Parastomalis sérvek
Authors: Nagy Attila , Jánó Zoltán
Published: October 2010

Absztrakt

A parastomalis sérvek gyakorisága 35–50%. A rekonstrukciójukra használt módszerek (helyben hagyott stoma körüli hasfal-rekonstrukció, stomaáthelyezés és sérvkapuzárás, különböző módszerrel beültetett különböző típusú hálók) sem hoztak kielégítő eredményeket.

Az endoscopos módszerek elkerülik a stoma körüli metszést, csökkentik a háló felülfertőződésének veszélyét. A sok próbálkozás ellenére a rekonstrukciók után az újabb recidívaarány még mindig 12–35% között maradt.

A nem kielégítő eredmények alapján egyre erőteljesebben vetődik fel a stomakészítéssel egy időben beültetett hálók használata. Szerzők saját speciális, kétrétegű, hengeres összekötőelemmel kiegészített preventív hálóbeültetéssel képzett 17 stoma 5 éves utánvizsgálata során egyetlen parastomalis sérvet sem észleltek, összes szövődményük egy könnyen korrigálható bőrszintű strictura volt. Tapasztalataik alapján megfontolandónak tartják a preventív hálóbeültetést a véglegesnek szánt stoma készítése során.
A különböző szilikonbevonatú polipropilén hálók szöveti integrációja
Authors: Takács Ildikó , Horváth Szabolcs , Balatonyi Borbála , Jávor Szaniszló , Molnár Ágnes , Gáspár Sarolta , Hajós Rebeka , Meczker Ágnes , Lantos János , Rőth Erzsébet , Wéber György
Published: October 2010

Absztrakt

Bevezetés/célkitűzés:A hasfali sérvek laparoscopos megoldásában a sebészi háló intraperitonealis pozícióban kerül beültetésre. Állatmodellekben és a humángyakorlatban egyaránt ígéretesek a kombinált, többrétegű hálók. Jelen kísérlet célja két eltérő szerkezetű, szilikonbevonatú polipropilén háló biológiai viselkedésének összehasonlítása volt.Anyag és módszerek:Új-zélandi fehér nyulak hasfalán egy 3 × 4 cm nagyságú, teljes vastagságú hasfaldefektust készítettünk, melyet összetett hálóval fedtünk. 20 állatba a felszínén lamináris szilikonréteggel bevont hálót (LSPP), a másik 20 nyúl esetében szilikonnal impregnált polipropilén filamentumból szőtt hálót (MSPP) ültettünk be. Az intraperitonealis adhaesioképződés mértékét és a hálók beépülését vizsgáltuk. Immunhisztokémiai módszerrel az osztódó sejtek jelenlétét és eloszlását az idegen anyag környezetében (Ki-67), az érújdonképződést (VEGF) és a kialakuló neoperitoneum-réteget (CK) vizsgáltuk, scanning elektronmikroszkóppal a halók felszínét tanulmányoztuk.Eredmények:Az intraperitonealis adhaesioképződés mértéke az első héten nem mutatott eltérést, míg a harmadik héten az LSPP szignifikánsan kevesebb kitapadást generált. A Ki-67 antitest jelölés szignifikánsan alacsonyabb aktivitású volt a makroporózus hálók csoportjában. Ugyanebben a csoportban a VEGF pozitivitás időarányosan nőtt, míg az LSPP esetében nem változott. A vékony neoperitoneum-réteg csak a makroporózus háló felszínén volt szövettanilag kimutatható (CK jelölés), az LSPP esetében hiányzott.Következtetések:A sebészi háló alapanyaga és textúrája is meghatározó szerepet játszik a befogadó szövetbe történő integrációban, mely arányos a kiváltott idegentest-reakcióval.
Linking Farmer Weed Management Behavior with Weed Pressure: More than Just Technology
Authors: Riemens Marleen M. , Groeneveld Roel M. W. , Kropff Martin J. J. , Lotz Lambertus A. P. , Renes Reint Jan , Sukkel Wijnand , van der Weide Rommie Y.
Published: October 2010

Most studies on weed population dynamics in farming systems have focused on the effects of different weed control strategies. Those studies usually assume that farmers, operating within a particular system, have a uniform management style. However, it is likely that weed management decision making also varies between farmers that operate within a system. In this study, the relationship between weed management behavior and the outcome of that behavior within an organic farming system is studied. It is hypothesized that differences in weed pressure between organic farms can be related to differences in farmers' weed management behavior. We explore which weed and general management factors are of main influence on the weed pressure, and investigate the influence of farmer's beliefs and knowledge on weed control techniques and the observed weed pressure. Preventive measures and timing of main soil tillage operation were identified as the weed management factors most influential for weed pressure. With the increasing number of preventive measures applied, weed pressure decreased, with a stale seedbed being the most important preventive measure. The weed pressure increased with the number of days after September 1st on which the main tillage operation was carried out. Because of this postponement of the tillage treatments, the growing season of weeds was extended and more species were able to reproduce before winter, thereby enhancing weed pressure. Field size, rather than weed pressure, determined the number of hand-weeding hours per ha; with increasing field size the amount of hand weeding per surface area was reduced. On farms with lower weed pressures a higher percentage of competitive crops were grown than on farms with higher weed pressures. The farmer's beliefs and knowledge on weed control techniques differed between farmers with different weed pressures. Market-oriented growers had a higher on-farm weed pressure than crop-growth–oriented growers. It was concluded that studies on weed management behavior and the effect of that behavior can lead to a better understanding of farming systems and to more effective weed management in those systems.
Influence of Winter Annual Weed Removal Timings on Soybean Cyst Nematode Population Density and Plant Biomass
Authors: Mock Valerie A. , Creech J. Earl , Ferris Virginia R. , Hallett Steven G. , Johnson William G.
Published: October 2010

Soybean cyst nematode (SCN) is one of the most yield limiting pathogens in U.S. soybean production. Henbit and purple deadnettle are winter annual weeds shown to facilitate SCN reproduction after crop harvest in the eastern Corn Belt. These weeds, along with volunteer soybean that germinates in autumn after harvest, are common to postharvest soybean production fields and provide an opportunity for SCN reproduction and population increase outside of the typical soybean production season. The objective of this experiment was to determine if autumn removal of these weeds and volunteer soybean can influence the winter weed seedbank, plant biomass, and SCN population densities. Microplots were established with or without Lamium spp. and volunteer soybean, and four winter weed removal timings (none, October, December, and May). Dry weights of autumn Lamium spp. were reduced 50% in October when grown in competition with volunteer soybean. SCN juveniles were found in henbit roots at higher densities in October (42 per gram of root) than December (5 per gram of root) and were also found in the roots of volunteer soybean (14 per gram of root) in October. SCN egg population densities were 50% lower in August after the summer fallow period. The results of this experiment suggest that autumn removal of winter annual weeds and volunteer soybean did not reduce SCN populations.
Efficacy of Flazasulfuron for Control of Annual Bluegrass (Poa annua) and Perennial Ryegrass (Lolium perenne) as Influenced by Nitrogen
Authors: Brosnan James T. , Thoms Adam W. , McCullough Patrick E. , Armel Gregory R. , Breeden Gregory K. , Sorochan John C. , Mueller Thomas C.
Published: October 2010

Certain sulfonylurea (SU) herbicides are used to remove overseeded cool-season species from bermudagrass. The effects of nitrogen (N) on the efficacy of a new SU herbicide, flazasulfuron, have not been determined. Field and laboratory studies were conducted in 2008 and 2009 evaluating the efficacy of flazasulfuron for control of overseeded perennial ryegrass contaminated with annual bluegrass. Flazasulfuron was applied at rates of 4.4, 8.8, and 17.5 g ha−1alone, and in between sequential applications of N fertilizer at 73 kg N ha−1. N was granularly applied immediately prior to herbicide treatment and 4 wk later. In both years, the level of annual bluegrass control with flazasulfuron and two applications of N at 73 kg N ha−1was significantly greater than following treatment with flazasulfuron alone. This response was observed for all application rates of flazasulfuron on every rating date. The level of annual bluegrass control with flazasulfuron at 4.4 g ha−1and two applications of N at 73 kg ha−1was greater than flazasulfuron at 17.5 g ha−1alone each year. No significant differences in perennial ryegrass control were observed for flazasulfuron with and without N fertility. In laboratory studies with annual bluegrass, treatment with N fertilizer at 73 kg N ha−1increased translocation of14C flazasulfuron (and any potential metabolites) from treated annual bluegrass leaves to other shoot tissues by 18% at 1 h after treatment and 22% at 4 h after treatment compared to plants not treated with N fertilizer. This increase in translocation may explain the increased level of annual bluegrass control observed in the field.
Annual Changes in Temperature and Light Requirements for Germination of Palmer Amaranth (Amaranthus palmeri) Seeds Retrieved from Soil
Authors: Jha Prashant , Norsworthy Jason K. , Riley Melissa B. , Bridges William
Published: October 2010

Experiments were conducted on Palmer amaranth seeds collected in 2004 and 2006 from a natural population near Pendleton, SC, to determine the temperature and light requirements for germination of seeds retrieved from soil surface or from 10-cm depth in the field. A cyclic change in seed germination of Palmer amaranth in response to temperature and light occurred during a 12-mo after-ripening period. Freshly matured seeds collected in November required mean temperatures ≥ 25 C, and natural or red (R) light for increased germination. Following after-ripening in winter, seeds experienced a reduction in dormancy and germinated higher at 25 to 35 C mean compared with 10 to 15 C mean. With after-ripening for an additional 3 mo in May, seeds experienced a broadening of thermal range (10 to 40 C mean), and germination in natural light or R light was more than twice the germination in the absence of light. Fluctuating temperatures (7.5 C amplitude) improved germination over constant temperatures, except in summer and fall (9 and 12 mo after seed maturation). Exposure of seeds to high temperatures during summer caused secondary dormancy induction. Averaged over thermal amplitudes, seeds retrieved in fall required mean temperatures > 25 C for increased germination. Burial in spring for 3 to 6 mo induced seed dormancy, and the relative germination in fall (12 mo after seed maturation) was at least 50% higher for seeds retrieved from soil surface compared to seeds exhumed from 10-cm soil depth. Seeds retrieved in late summer and fall required natural light or R light for promoting germination, whereas far-red (FR) light or darkness inhibited germination. Furthermore, the effect of R and FR light was reversible, indicating a partially phytochrome-mediated germination response of Palmer amaranth seeds following 9 to 12 mo of after-ripening in the field.
Effect of Soil pH and Previous Atrazine Use History on Atrazine Degradation in a Tennessee Field Soil
Authors: Mueller Thomas C. , Steckel Lawrence E. , Radosevich Mark
Published: October 2010

Field studies examined the interaction of soil pH with differing levels of atrazine exposure over 4 yr. Soil pH was 5.2 to 7.1 with atrazine exposures ranging from none (0) to eight applications over a 4-yr period (for each year, one application at planting and one early postemergence). The entire plot area was uniformly managed to reduce potential confounding effects due to cropping history, tillage, and other factors. Soil from all plots previously treated with atrazine displayed rapid atrazine dissipation, with half-lives under laboratory conditions being less than 4 d in plots of pH 5.5 or greater and less than 8 d in the field. Soil pH had a marked effect, with slower atrazine dissipation in those plots that had a pH 5.5 or less. This effect of pH and previous atrazine history was consistent in laboratory and field environments. Implications of these findings include probable reduction in weed control due to more rapid atrazine dissipation and potentially reduced loadings into surface water due to this phenomenon.
Assessing Genetic Diversity of Canada Thistle (Cirsium arvense) in North America with Microsatellites
Authors: Bodo Slotta Tracey A. , Foley Michael E. , Chao Shaioman , Hufbauer Ruth A. , Horvath David P.
Published: October 2010

Invasive species such as Canada thistle pose a significant threat to ecosystems. The risk of introducing invasive species has increased with human activities, and the effects of such events have economic and aesthetic impacts. Native to Europe, Canada thistle is now established throughout temperate North America. Although there is documentation of early occurrences to North America, little is known on how it has become established in diverse habitats or how it continues to spread. We examined genetic diversity within and among nearly 1,700 Canada thistle individuals from 85 North American locations with the use of seven microsatellite markers in order to address these questions. PAUP and STRUCTURE programs were used to assess genetic diversity and relationships within and between populations. Populations exhibited greater within-population diversity (> 60%) than expected for a reported clonally reproducing species. Total diversity of sampled locations in North America (0.183) was less than previously reported for European locations (0.715), but the greater mean difference between North American populations (0.264 relative to 0.246 from England) suggests strong founder effects or restriction of gene flow influencing individual populations. Furthermore, analyses identified numerous instances where individuals from geographically distant regions clustered together, indicating long-distance translocation of propogules. However, isolation by distance analysis showed significant correlation between location and population genetic distances (r= 0.1917, P = 0.006). Within populations, nearly 92% of individuals sampled harbored unique multilocus genotypes, strongly suggesting that sexual reproduction is common. Within populations, analysis of genetic structure indicated significant admixture of genotypes throughout the invasive range in North America. The recurrent distribution of seed throughout North America has led to a highly diverse gene pool and increased the adaptive success Canada thistle to a wide variety of habitats. Future technologies developed for control of Canada thistle should consider this diversity.
Picloram and Aminopyralid Sorption to Soil and Clay Minerals
Authors: Fast Brandon J. , Ferrell Jason A. , MacDonald Gregory E. , Krutz L. Jason , Kline William N.
Published: October 2010

Research was conducted to determine picloram and aminopyralid sorption in five soils and three clay minerals and to determine if the potential for off-target movement of aminopyralid in soil is less than that of picloram. Nearly all sorption of picloram and aminopyralid occurred between 0 and 8 h, and the maximum theoretical sorption of picloram and aminopyralid were 10.3 and 15.2%, respectively. Freundlich distribution coefficients (Kf) for picloram ranged from 0.12 in a Cecil sandy loam to 0.81 in an Arredondo fine sand, whileKfvalues for aminopyralid ranged from 0.35 in a Cecil sandy loam to 0.96 in an Arredondo fine sand. Furthermore,Kfvalues of aminopyralid were higher than those of picloram in all soils tested.Kfvalues of picloram in clay minerals were 0.25 (kaolinite), 1.17 (bentonite), and 1,016.4 (montmorillonite), and those of aminopyralid were 5.63 (kaolinite), 2.29 (bentonite), and 608.90 (montmorillonite). It was concluded that soil sorption of aminopyralid was greater than that of picloram and that the potential for off-target movement of aminopyralid is less than that of picloram.
Diffuse Knapweed (Centaurea diffusa) Seed Germination
Authors: Clements Charlie D. , Harmon Daniel , Young James A.
Published: October 2010

The objective of this study was to define further the environmental requirements for safe sites for germination of diffuse knapweed achenes (seeds). Germination temperature profiles were developed for diffuse knapweed seeds collected from sites in the Great Basin and Colorado. Each profile consisted of seeds germinated at 55 constant or alternating temperatures from 0 through 40 C. The resulting germination was used to develop quadratic response surfaces with regression analysis. Some germination occurred from 71 to 96% of the temperature regimes, depending on the accession being tested. Maximum observed germination ranged from 85 to 98%. Optimum germination, defined as the maximum observed minus one half the confidence interval at the 0.01 level of probability, occurred at a wide range of temperatures from cold periods of 0 through 20 C, alternating with warm periods of 10 through 35 C. The temperature regimes that most frequently supported optimum germination were 5/25 C (5 C for 16 h and 25 C for 8 h in each 24-h period) and 10/25 C. Germination of diffuse knapweed seeds was generally higher at alternating than constant temperatures.
Growth and Seed Production of Horseweed (Conyza canadensis) Populations after Exposure to Postemergence 2,4-D
Authors: Kruger Greg R. , Davis Vince M. , Weller Stephen C. , Johnson William G.
Published: October 2010

Horseweed can be a problematic weed in no-till soybean fields and populations can vary in their response to 2,4-D. The objective of this study was to evaluate the growth and seed production of four horseweed populations after exposure to 2,4-D. 2,4-D amine was applied at 0, 140, 280, and 560 g ae ha−1 to 5- to 10-cm-tall horseweed plants. An additional treatment of 280 g ha−1 of 2,4-D + 840 g ae ha−1 of glyphosate was included in the study. At 2 wk after treatment (WAT), injury ranged from 47 to 98%, but by 6 WAT the injury ranged from 89 to 100% for all four populations. Between 6 and 12 WAT some individual horseweed plants started to recover. No differences in dry weights were observed between the four populations in the untreated checks at 0, 2, 6, and 12 WAT. At 280 g ha−1 of 2,4-D amine, seed production was reduced by greater than 95%. However, three of the four horseweed populations had plants that survived and produced seed after exposure to 840 g ha−1 of glyphosate + 280 g ha−1 of 2,4-D. One plant produced seed after exposure to 560 g ha−1 of 2,4-D. These results suggest that horseweed can evolve resistance to 2,4-D and no fitness penalities were observed in populations that had higher levels of tolerance to 2,4-D.
Time of Emergence Affects Survival and Development of Wild Radish (Raphanus raphanistrum) in South Carolina
Authors: Norsworthy Jason K. , Malik Mayank S. , Riley Melissa B. , Bridges William
Published: October 2010

Field experiments were conducted from 2004 through 2006 at Pendleton and Clemson, SC, to determine the influence of seasonal emergence of wild radish on phenological development, survival, and seed and biomass production in a noncompetitive environment. The duration of four developmental phases, emergence to bolting, bolting to flowering, flowering to silique production, and silique production to maturity, were recorded following wild radish sowing at monthly intervals from October 2004 through September 2006. Seedling emergence occurred 2 to 4 wk after sowing. Mortality of seedlings that emerged from December through March was greater than that of seedlings that emerged in all other months. Wild radish that emerged from April through August completed its life cycle by summer or early autumn. Wild radish that emerged from September through November was able to survive the winter and complete its life cycle the following spring. The developmental phases most affected by time of emergence were emergence to bolting and bolting to flowering. The duration of emergence to bolting ranged from 249 to 479 growing degree days (GDD), and bolting to flowering from 270 to 373 GDD, depending on the month of emergence. The total life cycle of wild radish varied from a low of 1,267 GDD following June emergence to 1,503 GDD following November emergence. Multiple regression analysis revealed that emergence to bolting and silique production to maturity phases were dependent on accumulated heat units and photoperiod. Seed and biomass production were influenced by month of emergence. An average of 1,470 seeds plant−1was produced when emergence occurred in July and 10,170 seeds plant−1when emergence occurred in November. Plants that emerged in autumn exhibited minimal growth during the winter months, but conditions were conducive for growth in mid-March and April, with biomass production of 809 g plant−1at silique production.
‘In the interests of safety…’
Authors: Warren Alan
Published: October 2010

Since the Environment Agency took over the role as the enforcement authority for the Reservoirs Act 1975 in 2004, all periodical (section 10) inspection reports for large raised reservoirs in England and Wales containing statutory safety recommendations have been copied to the Agency's reservoir safety team in Exeter. It is now possible to benefit from the centralisation of several hundred reports. This article gives some insight to the areas of concern raised by inspecting engineers over the last 5 years.
Reassessment of Scottish and Southern Energy dams for PMF conditions
Authors: Morison Tony , Dempster Kenny
Published: October 2010

Since 2003, Halcrow Group has carried out seismic and, where appropriate, probable maximum flood (PMF) stability analyses on all Scottish and Southern Energy's dams in Scotland. Initial screening studies identified a number of concrete gravity dams where conventional stability and preliminary finite-element analyses indicated potential instability under PMF conditions. This paper describes a range of different approaches taken to address these issues, including hydrological reassessment, more sophisticated structural analysis and foundation anchoring. Development of evacuation plans is also under consideration for one intractable case.
Shrinkage-induced strains on cross-sections of reinforced concrete prisms
Authors: Al-Saleh S.A. , Al-Zaid R.Z.
Published: October 2010

This paper describes experimental testing to investigate the effects of steel reinforcement on the distribution of shrinkage strains over cross-sections of reinforced concrete (RC) prisms. Measurements were taken in a harsh environment (50°C and 5% relative humidity (RH) and a moderate environment (28°C and 50% RH) on prisms of dimensions (80 × 150 × 500 mm). The research provides experimental measurements that supplement the scarce database for the distribution of induced drying shrinkage strains over RC cross-sections. As expected, the presence of steel restrains the development of shrinkage strains and the degree of restraint depends on the amount of steel. The effect of reinforcing steel on induced strains at the upper levels of the cross-sections increases as the steel ratio increases, particularly for specimens cured in the harsh environment. Over time, the distributions of total strains over cross-sections were found to approach linearity, with a higher rate towards linearity as the steel ratio was increased.
The influence of concrete substrate preparation on overlay bond strength
Authors: Beushausen H.
Published: October 2010

Repair and strengthening of concrete structures often include the application of a concrete overlay to the existing substrate. Sufficient bond strength between substrate and overlay is a prerequisite for the durability and serviceability of the repaired or strengthened structure. Factors considered most important for good bond strength between substrate and overlay are cleanliness and texture of the substrate concrete surface, as well as overlay placement and curing techniques. In terms of substrate moisture condition prior to overlay application, a saturated, surface-dry substrate is generally considered best practice to achieve high bond strength. In some cases, bonding agents are specified, which may consist of commercial products or site-made cement slurries. Despite the extensive application of bonded concrete overlays, the usefulness of bonding agents is still the subject of much debate among researchers, specifiers and practitioners. Conflicting opinions also still exist as to whether pre-wetting the substrate concrete can be expected to have a positive influence on bond strength. The laboratory-based research described in this paper identified that a saturated, surface-dry substrate concrete has generally no beneficial influence on overlay bond strength. In many instances, the use of substrate surfaces prepared to what is commonly considered the optimum moisture condition resulted in significantly lower bond strength, compared with non-preconditioned substrates. This phenomenon was ascribed to better mechanical interlock, which exists when the fresh overlay material can flow into the unsaturated cavities and pores of the substrate. Bonding agents were found to enhance bond strength only when an overlay of low workability was applied, both commercial and self-made bonding agents performing equally well. For overlays with workability characteristics of conventional concretes (slump values between 70 and 110 mm), bonding agents were found to have no noticeable influence on bond strength. This relates to the circumstance that overlays of sufficient fluidity can fill the pores and cavities of the substrate without the help of a bonding agent.