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Humid Conditions (humid + condition)
Selected AbstractsKinetics of toluene sorption and desorption in Ca- and Cu-montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2004Yang-Hsin Shih Abstract Clays in soils or groundwater aquifer materials play roles in the sorption of organic pollutants. The intrinsic sorption kinetics of toluene in dry and humid clay films was investigated by tracking the change of infrared absorbance. Under the humid condition, similar toluene-sorbed intensities were found in Ca- and Cu-montmorillonites. However, a higher intensity of sorbed toluene was found in the Cu-form than in the Ca-form under the dry condition, which indicates a stronger interaction occurring in dry Cu-montmorillonite. The general time scale of sorption of toluene on clays is around 100 s. In both forms of montmorillonite, some portion of toluene was desorbed at an extremely slow rate under the dry condition. Some newly identified peaks were persistent against desorption from montmorillonites, suggesting the existence of irreversibly sorbed species and the possibility of toluene transformation occurring in clay systems. [source] A Rb/Sr record of catchment weathering response to Holocene climate change in Inner MongoliaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2006Zhangdong Jin Abstract Variation in the rubidium to strontium (Rb/Sr) ratio of the loess,palaeosol sequences has been proposed to reflect the degree of pedogenesis and weathering in the northwestern region of China. To characterize the Rb/Sr ratio of the dissolved loads of a single catchment, we analysed a 12·08 m sediment core from Daihai Lake in Inner Mongolia, north China. Dating control was provided by 210Pb, 137Cs and AMS- 14C. Sequential extraction experiments were conducted to investigate the concentrations of Rb and Sr on various chemical fractions in the lake sediments. Down-core variation in the Rb/Sr ratios provides a record of Holocene weathering history. From 9 to 3·5 ka bp, accelerated chemical weathering was experienced throughout the Daihai catchment under mainly warm and humid conditions, and this reached a maximum at c. 5 ka bp. However, weathering was reduced between c. 8·25 and 7·90 ka bp, which may reflect the global 8·2 ka cooling event. After c. 2·5 ka bp, increased Rb/Sr ratios with higher frequency of fluctuations indicate reduced weathering within the Daihai catchment. The highest Rb/Sr ratios in the Little Ice Age lake sediments indicate the weakest phase of Holocene chemical weathering, resulting from a marked reduction in Sr flux into the basin. The Rb/Sr record also shows an enhancement of chemical weathering under today's climate, but its intensity is less than that of the Medieval Warm Period. Increased Rb/Sr in lake sediment corresponding to reduced catchment weathering is in striking contrast to Rb/Sr decrease in the glacial loess layers in the loess,palaeosol sequence. Copyright © 2005 John Wiley & Sons, Ltd. [source] The influence of the environment and corrosion on the structural integrity of aircraft materialsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 6 2009S. RUSSO ABSTRACT Fatigue results of 11/2 dog-bone jointed specimens manufactured from 7075-T6 aluminium alloy indicated that the application of corrosion preventative compounds (CPCs) at the faying surfaces slightly decreased the log mean fatigue life at 144 MPa, while the effect was not statistically significant at the higher stress level (210 MPa). The addition of the CPC also reduced fretting corrosion at the faying surfaces and shifted the fatigue initiation sites closer to the edge of fastener holes. Scatter in fatigue life was found to be associated with the location and size of the intermetallics at the initiation site. The presence of corrosion in the bores of the countersunk fastener holes reduced the fatigue life by up to one order of magnitude. Fatigue test results for dog-bone specimens manufactured from 7075-T651 and 2024-T351 aluminium alloys indicated that the presence of exfoliation corrosion reduced the fatigue life under dry conditions, with a greater reduction under humid conditions. The application of a CPC to the corroded region eliminated the influence humidity had on fatigue life. [source] Palaeoecology and depositional environments of the Tendaguru Beds (Late Jurassic to Early Cretaceous, Tanzania)FOSSIL RECORD-MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE, Issue 1 2002Martin Aberhan Abstract The Late Jurassic to Early Cretaceous Tendaguru Beds (Tanzania, East Africa) have been well known for nearly a century for their diverse dinosaur assemblages. Here, we present sedimentological and palaeontological data collected by the German-Tanzanian Tendaguru Expedition 2000 in an attempt to reconstruct the palaeo-ecosystems of the Tendaguru Beds at their type locality. Our reconstructions are based on sedimentological data and on a palaeoecological analysis of macroinvertebrates, microvertebrates, plant fossils and microfossils (ostracods, foraminifera, charophytes, palynomorphs). In addition, we included data from previous expeditions, particularly those on the dinosaur assemblages. The environmental model of the Tendaguru Beds presented herein comprises three broad palaeoenvironmental units in a marginal marine setting: (1) Lagoon-like, shallow marine environments above fair weather wave base and with evidence of tides and storms. These formed behind barriers such as ooid bar and siliciclastic sand bar complexes and were generally subject to minor salinity fluctuations. (2) Extended tidal flats and low-relief coastal plains. These include low-energy, brackish coastal lakes and ponds as well as pools and small fluvial channels of coastal plains in which the large dinosaurs were buried. Since these environments apparently were, at best, poorly vegetated, the main feeding grounds of giant sauropods must have been elsewhere. Presumably, tidal flats and coastal plains were visited by dinosaurs primarily during periods of drought. (3) Vegetated hinterland. Vegetation of this environment can only be inferred indirectly from plant material transported into the other depositional environments. Vegetation was dominated by a diverse conifer flora, which apparently formed part of the food source of large herbivorous sauropods. Evidence from various sources suggests a subtropical to tropical palaeoclimate, characterised by seasonal rainfall alternating with a pronounced dry season during the Late Jurassic. In Early Cretaceous times, sedimentological and palaeontological proxies suggest a climatic shift towards more humid conditions. Die Tendaguru-Schichten von Tansania in Ostafrika (Oberjura bis Unterkreide) sind als Lagerstätte oberjurassischer Dinosaurier seit nahezu einem Jahrhundert weltweit bekannt. Anhand von sedimentologischen und paläontologischen Daten, die während der Deutsch-Tansanischen Tendaguru Expedition 2000 im Typus-Gebiet der Tendaguru-Schichten gewonnen wurden, werden Paläo-Ökosysteme rekonstruiert. Grundlage der Rekonstruktionen sind die Auswertung sedimentologischer Daten sowie die paläo-ökologische Analyse von Makroinvertebraten, Mikrovertebraten, pflanzlichen Fossilien und Mikrofossilien (Ostrakoden, Foraminiferen, Charophyten, Palynomorphen). Darüber hinaus werden Informationen über Dinosaurier berücksichtigt, die bei früheren Expeditionen gewonnen wurden. Das hier vorgestellte Ablagerungsmodell der Tendaguru-Schichten umfaßt drei Teilbereiche eines randlich marinen Sedimentationsraumes, die wie folgt gekennzeichnet werden können: (1) Lagunen-artige, marine Flachwasserbereiche, die oberhalb der Schönwetter-Wellenbasis lagen und unter deutlichem Einfluß von Gezeiten und Stürmen standen. Sie waren vom offenen Meer durch Barrieren, wie Ooidbarren und siliziklastischen Sandbarrenkomplexen, getrennt und wiesen einen leicht schwankenden Salzgehalt auf. (2) Ausgedehnte Wattgebiete und flache Küstenebenen. Dort befanden sich niedrig-energetische, brackische Strandseen und Teiche sowie Tümpel und kleinere Flußrinnen, in denen die großen Dinosaurier eingebettet wurden. Da diese Lebensräume bestenfalls dürftig bewachsen waren, müssen die Nahrungsquellen und der eigentliche Lebensraum der riesigen Sauropoden anderswo gelegen haben. Vermutlich wurden die Wattgebiete und Flachküsten von Dinosauriern vorrangig in den Trockenzeiten aufgesucht. (3 ) Bewachsenes Hinterland. Die Vegetation dieses Lebensraumes kann nur indirekt aus Pflanzenresten erschlossen werden, die in die anderen Ablagerungsraume transportiert wurden. Die Vegetation wurde von einer diversen Koniferenflora dominiert, die zumindest teilweise die Nahrungsgrundlage der großen, herbivoren Sauropoden bildete. Sedimentologische und paläontologische Indikatoren sprechen für ein subtropisches bis tropisches Klima wahrend der späten Jurazeit mit einem jahreszeitlichen Wechsel von Regenfällen und ausgeprägten Trockenzeiten. In der frühen Kreidezeit deutet sich ein Wechsel zu starker humiden Bedingungen an. [source] Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Oscar Larsson Abstract Electrolyte-gated organic field-effect transistors (OFETs) hold promise for robust printed electronics operating at low voltages. The polarization mechanism of thin solid electrolyte films, the gate insulator in such OFETs, is still unclear and appears to limit the transient current characteristics of the transistors. Here, the polarization response of a thin proton membrane, a poly(styrenesulfonic acid) film, is controlled by varying the relative humidity. The formation of the conducting transistor channel follows the polarization of the polyelectrolyte, such that the drain transient current characteristics versus the time are rationalized by three different polarization mechanisms: the dipolar relaxation at high frequencies, the ionic relaxation (migration) at intermediate frequencies, and the electric double-layer formation at the polyelectrolyte interfaces at low frequencies. The electric double layers of polyelectrolyte capacitors are formed in ,1,µs at humid conditions and an effective capacitance per area of 10,µF cm,2 is obtained at 1,MHz, thus suggesting that this class of OFETs might operate at up to 1,MHz at 1,V. [source] Two-step vegetation response to enhanced precipitation in Northeast Brazil during Heinrich event 1GLOBAL CHANGE BIOLOGY, Issue 6 2010LYDIE M. DUPONT Abstract High resolution palynological and geochemical data of sediment core GeoB 3910-2 (located offshore Northeast Brazil) spanning the period between 19 600 and 14 500 calibrated year bp (19.6,14.5 ka) show a land-cover change in the catchment area of local rivers in two steps related to changes in precipitation associated with Heinrich Event 1 (H1 stadial). At the end of the last glacial maximum, the landscape in semi-arid Northeast Brazil was dominated by a very dry type of caatinga vegetation, mainly composed of grasslands with some herbs and shrubs. After 18 ka, considerably more humid conditions are suggested by changes in the vegetation and by Corg and C/N data indicative of fluvial erosion. The caatinga became wetter and along lakes and rivers, sedges and gallery forest expanded. The most humid period was recorded between 16.5 and 15 ka, when humid gallery (and floodplain) forest and even small patches of mountainous Atlantic rain forest occurred together with dry forest, the latter being considered as a rather lush type of caatinga vegetation. During this humid phase erosion decreased as less lithogenic material and more organic terrestrial material were deposited on the continental slope of northern Brazil. After 15 ka arid conditions returned. During the humid second phase of the H1 stadial, a rich variety of landscapes existed in Northeast Brazil and during the drier periods small pockets of forest could probably survive in favorable spots, which would have increased the resilience of the forest to climate change. [source] An in vitro comparison of pH changes in root dentine following canal dressing with calcium hydroxide points and a conventional calcium hydroxide pasteINTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2002S. M. Ardeshna Abstract Aim This study aimed to measure and compare pH changes at apical and cervical sites on the external root surface of extracted teeth dressed with calcium hydroxide in two different formulations. Methodology Root canals of 45 single-rooted extracted human teeth were accessed and shaped using a step-down technique with rotary instrumentation. Standard cavities were prepared on the external root surface at specific apical and cervical sites. The teeth were randomly allocated to three groups. Teeth in group A were dressed with calcium hydroxide points, those in group B were dressed with an aqueous calcium hydroxide paste and teeth in group C were left unfilled. Following storage in humid conditions, the pH of the dentine at apical and cervical sites was measured at baseline and then at 24 h, 72 h, 1 week, 10 days, 2 weeks and 3 weeks. Results The pH of the root dentine at both apical and cervical sites was significantly greater (P < 0.001) in teeth dressed with aqueous calcium hydroxide paste compared with those dressed with calcium hydroxide points, when averaged out across all time periods. For all groups, there was a significant difference between the mean apical and cervical pH values for each tooth with lower values for the apical sites (P < 0.001). Conclusion The results of this study indicate that an aqueous calcium hydroxide paste was more effective than calcium hydroxide points at raising the pH on the external root surface of extracted teeth. [source] A multi-sample design for assessing the comedolytic activity of topical productsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2004H. Knaggs Synopsis Background:, Facial comedolytic studies allow testing of a maximum of two products. The upper back provides a larger area with a more uniform distribution of microcomedones for comedolytic studies. Objective:, To design a multi-sample method for assessing comedolytic activity of topical products on the back. The effect of season on product discrimination was also explored. Methods:, Three cleansing formulations (products B, C and D), a negative water control and 0.025% Retin-A® cream (positive control) were tested. Seven subjects were recruited in summer and nine in fall. Products were applied for 8 weeks, comedolysis was assessed by visually evaluating cyanoacrylate follicular biopsies taken at baseline and post-treatment. Results:, In all data sets (summer, fall and combined), sites treated with Retin-A® had a significantly lower number of microcomedones as compared to the negative water control. In addition, cleansers B and D showed a significant reduction from baseline in the fall and combined (summer and fall) data, but not in summer data alone indicating different responses to treatment during the year. Conclusions:, The design was sensitive enough to detect differences between cleansing formulations under normal washing conditions. Reduced sensitivity observed during summer suggests hot humid conditions may decrease the comedolytic performance of topical products. Résumé Arrière-plan:, Les études d'agents comédolytiques sur le visage permettent de tester un maximum de deux produits. La partie supérieure du dos offre une plus grande surface couverte d'une distribution plus uniforme de micro-comédons. Objectif:, Mettre au point une méthode multi échantillons permettant d'appréhender l'activité comédolytique de produits appliqués de façon topique sur le dos. L'influence de la saison sur la différenciation des produits a également étéétudiée. Méthode:, Trois formulations lavantes (B, C, D), l'eau en tant que témoin négatif, une crème contenant 0,025% de rétina-A® en tant que témoin positif ont été testées. Sept sujets ont été recrutés en été, neuf l'ont été en automne. Les produits ont été appliqués durant 8 semaines. La comédolyse a étéévaluée par observation visuelle de biopsies folliculaires au cyanoacrylate faite avant et après traitement. Résultat:, Dans chaque groupe de résultats (été, automne et cumulé), les zones traitées avec la rétina-A® possèdent un nombre de micro-comédons statistiquement plus faible, comparé au témoin négatif (l'eau). De plus, les produits de nettoyage B et D ont montré une diminution significative par rapport à la situation avant traitement en automne, ainsi qu'en situation cumulé (automne + été), mais pas en été. Ces résultats indiquent des réponses différentes au traitement durant l'année. Conclusion:, La méthode est assez sensible pour détecter la différence entre des formulations nettoyantes utilisées sous condition normale d'utilisation. La diminution de sensibilité observée en été laisse suggérer que des conditions climatiques chaudes et humides diminuent l'efficacité comédolytique des produits appliqués de façon topique. [source] Performance enhancement of gas turbines by inlet air-cooling in hot and humid climatesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2006Majed M. Alhazmy Abstract In this paper, a model to study the effect of inlet air-cooling on gas turbines power and efficiency is developed for two different cooling techniques, direct mechanical refrigeration and an evaporative water spray cooler. Energy analysis is used to present the performance improvement in terms of power gain ratio and thermal efficiency change factors. Relationships are derived for an open gas turbine cycle with irreversible compression and expansion processes coupled to air-cooling systems. The obtained results show that the power and efficiency improvements are functions of the ambient conditions and the gas turbine pressure ratio. The performance improvement is calculated for, ambient temperatures from 30 to 50°C, the whole range of humidity ratio (10,100%) and pressure ratio from 8 to 12. For direct mechanical refrigeration air-cooling, the power improvement is associated with appreciable drop in the thermal efficiency. The maximum power gain can be obtained if the air temperature is reduced to its lowest limit that is the refrigerant evaporation temperature plus the evaporator design temperature difference. Water spray cooling process is sensitive to the ambient relative humidity and is suitable for dry air conditions. The power gain and efficiency enhancement are limited by the wet bulb temperature. The performance of spray evaporative cooler is presented in a dimensionless working graph. The daily performance of the cooling methods is examined for an ABB-11D5 gas turbine operating under the hot humid conditions of Jeddah, Saudi Arabia. The results indicate that the direct mechanical refrigeration increased the daily power output by 6.77% versus 2.57% for the spray air-cooling. Copyright © 2005 John Wiley & Sons, Ltd. [source] Seasonal influenza activity in Hong Kong and its association with meteorological variationsJOURNAL OF MEDICAL VIROLOGY, Issue 10 2009Paul K.S. Chan Abstract Influenza seasons appear consistently in the temperate regions, but are more variable in tropical/subtropical regions. The determinant for such variation remains poorly understood. This study documented the activity of influenza over a 10-year period in Hong Kong; examining its association with changes in temperature and relative humidity. The two types of influenza exhibited different correlations with meteorological variations. Influenza A showed two seasonal peaks occurring respectively in winter/spring and summer months in most years. Influenza B showed a clear winter/spring peak, but its activity during summer months was more variable. Cold and humid conditions were associated with a higher activity of both influenza A and B. In contrast, hot and humid conditions were associated with a higher activity of influenza A, but were associated with only a moderate, less consistent increase in the activity of influenza B. A trend of increase in the magnitude of summer peaks of influenza A, but not influenza B, was observed. A hypothetical 2°C rise in temperature would decrease the proportion of favorable days for influenza A in December,April from 78% to 57%, but an increase from 58% to 71% in May,November; with a similar effect (from 83% to 62%) for influenza B during December,April, but a modest change (from 17% to 18%) during May,November. The presence of two seasonal peaks of influenza annually emphasizes the need to evaluate the duration of protective immunity offered by vaccination. Further study on the effects of climate change and global warming on the activity of influenza is warranted. J. Med. Virol. 81:1797,1806, 2009. © 2009 Wiley-Liss, Inc. [source] Synthesis of novel moisture-curable polyurethanes end-capped with trialkoxysilane and their application to one-component adhesivesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2007Yukihiro Nomura Abstract Novel silane endcappers and novel polyurethanes end-capped with trimethoxysilane (silylated polyurethanes) were developed as water-curable materials in which the curing reaction occurred under humid conditions in the presence of dioctyltin diversatate as a curing catalyst. A variety of amine-terminated trimethoxysilane compounds were synthesized by the Michael addition reaction of commercially available 3-aminopropyltrimethoxysilane with acrylates, and the resulting silane endcappers were used to react with isocyanate-terminated polyurethanes, providing the silylated polyurethanes. The moisture-curable silylated polyurethanes were used for the preparation of novel one-component and solvent-free adhesives. The evaluated properties were the curing speed, the tensile shear bond strength, and the adherence to some substrates. The longer alkyl chains of the silane endcappers derived from various acrylates led to a slower curing speed, lower tensile strength at break, and longer elongation at break of the silylated polyurethanes. The tensile shear bond strength of the silylated polyurethane-based adhesive decreased with decreasing the trimethoxysilane end-capping ratio, whereas an increase in the adherence was observed. The adherence to the acrylic substrate was improved by changes in the main-chain structure of the polyurethane based on the composition of poly(propylene oxide) and poly(ethylene oxide). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2689,2704, 2007 [source] Solid polymer electrolytes I, preparation, characterization, and ionic conductivity of gelled polymer electrolytes based on novel crosslinked siloxane/poly(ethylene glycol) polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2004Ping-Lin Kuo Abstract A series of crosslinked siloxane/poly(ethylene glycol) (Si,PEG) copolymers were synthesized from the reactive methoxy-functional silicone resin (Si resin) and PEGs with different molecular weights via two kinds of crosslinking reactions during an in situ curing stage. One of the crosslinking reactions is the self-condensation between two methoxy groups in the Si resin, and another one is an alkoxy-exchange reaction between the methoxy group in the Si resin and the OH group in PEG. The synthesized crosslinked copolymers were characterized by Fourier transform infrared spectroscopy, DSC, and 13C NMR. The crosslinked copolymers were stable in a moisture-free environment, but the SiOC linkages were hydrolyzed in humid conditions. The gel-like solid polymer electrolytes (SPEs) were prepared by impregnating these crosslinked Si,PEG copolymers in a propylene carbonate (LiClO4/PC) solution. The highest conductivity reached 2.4 × 10,4 S cm,1 at 25 °C and increased to 8.7 × 10,4 S cm,1 at 85 °C. The conductivities of these gel-type SPEs were affected by the content of LiClO4/PC, the molecular weights of PEGs, and the weight fraction of the Si resin. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2051,2059, 2004 [source] Palaeohydrology of Laguna de Tagua Tagua (34° 30, S) and moisture fluctuations in Central Chile for the last 46,000,yr,JOURNAL OF QUATERNARY SCIENCE, Issue 7-8 2005Blas L. Valero-Garcés Abstract Central Chile (32,35° S) lies at the northern border of the strong influence of the westerly circulation belt and thus exhibits a steep rainfall gradient. A new core from Laguna de Tagua Tagua (34° 30, S) provides a sedimentologic, geochemical and palynological record of regional hydrologic balance for the last 46,000,cal.,yr,BP. According to our age model, relatively humid conditions occurred during glacial times before 43,500,cal.,yr,BP and from 40,000 to 21,500,cal.,yr,BP. Reduced moisture conditions and likely lower temperatures occurred from 42,400,40,100,cal.,yr,BP. Higher lake levels, and pollen assemblages with Valdivian rainforest taxa, imply much higher precipitation during glacial times (40,100,21,000,cal.,yr,BP) compared to today and, therefore, enhanced westerly activity in northern Central Chile. Afterwards, the general decrease in moisture was punctuated by two abrupt arid periods at 21,000,19,500,cal.,yr,BP and 17,000,15,000,cal.,yr,BP, and two more humid intervals: 19,500,17,000 (almost coincident with the global Last Glacial Maximum, LGM) and 13,500,11,500,cal.,yr,BP. The early and mid-Holocene were the most arid periods in Central Chile for the studied time interval. Millennial-scale palaeohydrological reconstructions from Tagua Tagua are consistent with regional climatic records. Copyright © 2005 John Wiley & Sons, Ltd. [source] Phylogeography of sexual Heteronotia binoei (Gekkonidae) in the Australian arid zone: climatic cycling and repetitive hybridizationMOLECULAR ECOLOGY, Issue 9 2005JARED L. STRASBURG Abstract The biota of much of continental Australia have evolved within the context of gradual aridification of the region over several million years, and more recently of climatic cycling between relatively dry and humid conditions. We performed a phylogeographical study of three sexual chromosome races of the Heteronotia binoei complex of geckos found throughout the Australian arid zone. Two of these three races were involved in two separate hybridization events leading to parthenogenetic lineages (also H. binoei), and the third is widespread and broadly sympatric with the parthenogens. Based on our analyses, the three sexual races diversified approximately 6 million years ago in eastern Australia, during a period of aridification, then each moved west through northern, southern, and central dispersal corridors to occupy their current ranges. In each case, the timing of major phylogeographical inferences corresponds to inferred palaeoclimatic changes in continental Australia. This scenario provides a simple explanation for diversification, secondary contact, and hybridization between the races. However, data presented elsewhere indicate that formation of the parthenogens was considerably more recent than the westward expansion of the hybridizing races, and that multiple hybridization events were geographically and temporally distinct. We suggest that cyclical climate changes may have led to regional range changes that facilitated hybridization between the races, which are not currently known to be in sympatry. [source] Occurrence and survival of potato scab pathogens (Streptomyces species) on tuber lesions: quick diagnosis based on a PCR-based assayPLANT PATHOLOGY, Issue 3 2004M. J. Lehtonen A time-saving and cost-effective polymerase chain reaction (PCR)-based method was developed for species-specific detection of the scab pathogens (Streptomyces scabies and S. turgidiscabies) prevalent in potato (Solanum tuberosum) in northern Scandinavia. Species specificity of primers was verified using a collection of previously characterized Streptomyces strains isolated from potato scab lesions in Finland and Sweden. A total of 1245 scab lesions was tested from potato cvs Matilda and Sabina grown in the field in two geographic regions of Finland in 2000 and 2001. Freshly harvested or stored potato tubers were incubated at room temperature (18,21°C) under humid conditions for a few days. Bacterial growth was collected from scab lesions for DNA isolation and PCR. The two scab pathogens were detected in the same potato fields, tubers and scab lesions. The relative incidence of S. scabies was high in freshly harvested tubers but was much lower than that of S. turgidiscabies following storage. Both pathogens were seed-transmitted in Matilda and Sabina after 24 weeks of storage at 4°C. [source] The effect of modified roofing on the milk yield and reproductive performance of heat-stressed dairy cows under hot-humid conditionsANIMAL SCIENCE JOURNAL, Issue 5 2010Sriapa KHONGDEE ABSTRACT The objective was to measure the effects of cooling techniques (shade cloth vs. normal roof) on performance and physiology of 16 Friesian crossbred cows (87.5% Holstein Friesian × 12.5% Brahman) located at Sakol Nakhon Livestock Research and Testing Station, Department of Livestock Development, Ministry of Agriculture and Cooperatives (Sakol Nakhon, Thailand). They were divided randomly into two groups of eight. The two groups were used to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects' milk yield and reproductive performance under hot humid conditions. Results indicated that the modified roofing offered a more efficient way to minimize heat stress than the normal roof. The difference was sufficient to enable the cows to have a significantly lower mean rectal temperature and respiration rate (38.56°C, 61.97 breaths/min) than that of the cows housed under normal roofing (39.86°C; 85.16 breaths/min). The cows housed under modified roofing produced more milk (P < 0.05) but did not differ significantly in reproductive performance from the cows housed under normal roofing. [source] | ||||||||||||||||