bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relationship between structure and the hydraulic conductivity of soil
Authors: CRAWFORD J.W. 
Published: July 2006

SummaryA random fractal matrix comprising a hierarchical aggregation of primary structural elements is used to capture the characteristics of a heterogeneous soil structure with a tortuous pore space. The influence of heterogeneity of both the solid matrix and the pore space, as well as the shape of the pore boundary, on the saturated and unsaturated hydraulic conductivity is studied. For such random structures, the fractal (Hausdorff) dimension alone is not enough to characterize the structure from the point of view of fluid flow and additional characterizations are introduced. The porosity, ρp, of the primary elements has a critical value, ρc. With probability 1, both the saturated and unsaturated conductivities are found to be dependent as a power law on the length scale, L, at which the measurement is made when ρp>ρc. When ρp<ρc, only the unsaturated conductivity is scaling in length scale, while the saturated conductivity becomes dominated, with probability close to 1, by the conductivity of the largest connecting pores in the structure, i.e. preferential pathways. The relationships between the parameters of the power laws and structure are derived and are found to depend on the fractal (Hausdorff) and spectral dimensions of the solid matrix, denoted dm and respectively. A discussion of the importance of these results for the interpretation and extrapolation of measurements is presented, and the implications for variability and predictability of the hydraulic properties of soil is discussed.
The oral health and treatment needs of schoolchildren in Trinidad and Tobago: findings of a national survey
Authors: NAIDU R. , PREVATT I. , SIMEON D. 
Published: July 2006

Summary.  Objective.  To describe the oral health and treatment need of schoolchildren in Trinidad and Tobago.Design and method.  Cross‐sectional survey using stratified cluster sampling. Participants were children in primary (aged 6–8 years) and secondary school (aged 12 and 15 years). Main outcome measures were DMFT/dmft, treatment need, and fluorosis.Results.  Examinations were completed on 1064 children. The dmft of the 6–8‐year‐olds was 2·54 (95% CI = 2·32, 2·76). For 12‐year‐olds, the DMFT was 0·61 (95% CI = 0·51, 0·71), whereas for 15‐year‐olds, the DMFT was 1·06 (95% CI = 0·87, 1·25). Most of the caries experience in 6–8‐year‐olds was from decayed teeth. Sixty‐seven per cent of the sample (95% CI = 64%, 69%) had some type of treatment need. Most frequently occurring need was for fillings at 42% (95% CI = 40%, 44%) with 28% (95% CI = 26%, 31%) of the total sample needing two or more surface fillings, followed by fissure sealants at 33% (95% CI = 30%, 36%) and caries‐arresting care at 12% (95% CI = 10%, 14%). Extraction of one or more teeth was needed in 13% (95% CI = 11%, 15%) of children. Rates of fluorosis were negligible.Conclusion.  The caries experience of 12‐ and 15‐year‐old children were low but was high for schoolchildren aged 6–8 years, in terms of prevalence and severity. Effective oral health promotion strategies need to be implemented to improve the oral health of primary schoolchildren in Trinidad and Tobago.
A model‐independent test for the presence of regulatory equilibrium and non‐random structure in island species trajectories
Authors: Golinski Michael , Boecklen William J. 
Published: July 2006

AbstractAims  To test a key prevision of the dynamic equilibrium theory of island biogeography, namely that changes in species numbers on islands over time (hereafter, species trajectories) are equilibrial, and to characterize aspects of the dynamical properties of species change over time using a model‐independent test.Methods  We tested for regulatory equilibrium and non‐random structure in species numbers through time by comparing observed correlation coefficients at lag‐k for species trajectories from four true islands and two habitat islands. First, we estimated the shape of the autocorrelation function for each observed species trajectory by calculating correlation coefficients of the observed data between pairs of values Nt−k and Nt separated by lag‐k (k = 1, 2, …, N − 1). Second, we tested the observed correlation coefficients at each lag against a distribution of correlation coefficients generated by randomly ordering observed numbers in the species trajectories.Results  The patterns of autocorrelation functions for all but one of the observed species trajectories did not exhibit evidence of regulatory equilibrium, and, in fact, closely matched what would be expected from a non‐stationary or ‘random walk’ process. The majority of the correlation coefficients generated from the observed species trajectories did not deviate significantly from correlation coefficients produced by the randomized trajectories. However, there was strong evidence of unusual positive autocorrelation at small time lags for birds on islands measured annually (2‐ to 4‐year lags) and for arthropods on islands measured weekly (7‐ to 8‐week lags), suggesting some degree of structure in change in species richness over time.Main conclusions  The autocorrelation function patterns for all but one of the observed species trajectories showed various forms of non‐stationarity. These types of patterns suggest that the numbers of species through time gradually wandered away from their initial sizes. Our model‐independent test of individual correlation coefficients revealed significant structure in the observed species trajectories. These trajectories appear to be non‐random at relatively short lag intervals, indicating a process with short memory.
Transcriptome profiling uncovers metabolic and regulatory processes occurring during the transition from desiccation‐sensitive to desiccation‐tolerant stages in Medicago truncatula seeds
Authors: Buitink Julia , Leger Jean J. , Guisle Isabelle , Vu Benoit Ly , Wuillème Sylvie , Lamirault Guillaume , Bars Alice Le , Meur Nolwenn Le , Becker Anke , Küster Helge , Leprince Olivier 
Published: July 2006

SummaryTo investigate regulatory processes and protective mechanisms leading to desiccation tolerance (DT) in seeds, 16086‐element microarrays were used to monitor changes in the transcriptome of desiccation‐sensitive 3‐mm‐long radicles of Medicago truncatula seeds at different time points during incubation in a polyethylene glycol (PEG) solution at −1.7 MPa, resulting in a gradual re‐establishment of DT. Gene profiling was also performed on embryos before and after the acquisition of DT during maturation. More than 1300 genes were differentially expressed during the PEG incubation. A large number of genes involved in C metabolism are expressed during the re‐establishment of DT. Quantification of C reserves confirms that lipids, starch and oligosaccharides were mobilised, coinciding with the production of sucrose during the early osmotic adjustment. Several clusters of gene profiles were identified with different time‐scales. Genes expressed early during the PEG incubation belonged to classes involved in early stress and adaptation responses. Interestingly, several regulatory genes typically expressed during abiotic/drought stresses were also upregulated during maturation, arguing for the partial overlap of ABA‐dependent and ‐independent regulatory pathways involved in both drought and DT. At later time points, in parallel to the re‐establishment of DT, upregulated genes are comparable with those involved in late seed maturation. Concomitantly, a massive repression of genes belonging to numerous classes occurred, including cell cycle, biogenesis, primary and energy metabolism. The re‐establishment of DT in the germinated radicles appears to concur with a partial return to the quiescent state prior to germination.
DAS VERHALTEN VON RHIZOMEN DER QUECKE (AGROPYRON REPENS) GEGEN TROCKENE LUFT
Authors: GRÜMMER GERHARD 
Published: July 2006

Zusammenfassung. 1. Herausgeschnittene Stücke von Rhizomen der Quecke sind nur dann zur Entwicklung einer neuen Pflanze befähigt, wenn sie eine unbeschädigte und voll ausgebildete Knospe tragen.2. Rhizomteile von 1 cm Länge mit normal ausgebildeter Knospe konnten zu einem hohen Prozentsatz neue Pflanzen bilden. Wurden die Stücke in Längsrichtung halbiert, so kamen nur noch etwa die Hälfte der mit Knospen versehenen Teile zur Entwicklung. Selbst Stücke von nur 3 mm Länge mit intakter Knospe konnten noch zu 30% normale Pflanzen bilden.3. Mit zunehmender Verfärbung der Rhizome nach Braun und Schwarz nahm die Fähigkeit zur Bildung von Sprossen schnell ab.4. Stücke von 1 cm Länge mit normal ausgebildeter Knospe waren nach 6 Tagen ununterbrochenem Aufenthalt bei 56% relativer Feuchte nur noch zu 5% entwicklungsfähig. Bei gleichlangem Aufenthalt unter 66% relativer Feuchte trieben noch 25% aller Knospen aus, während bei 75% oder 88% relativer Feuchte keine Schädigung erkennbar war.5. Dünne Rhizomteile waren empfindlicher gegen trockene Luft als extrem dicke, kurze Stücke etwas empfindlicher als längere.6. Wechsel zwischen Trockenheit und Feuchte im Tag‐Nacht‐Rhythmus hatte eine wesentlich geringere Minderung der Entwicklungsfähigkeit zur Folge als eine ununterbrochene Einwirkung der Trockenheit von etwa gleicher Gesamtdauer.7. Bei extremer Trockenheit wurde die Wirkung durch eine kräftige Luftbewegung (bis zu 5,5 m/sec) wesentlich verstärkt.8. Die praktischen Folgerungen aus den Versuchen werden diskutiert.The reaction of rhizomes of Agropyron repens to dry air
CONTROL OF WEEDS IN MARROWSTEM KALE BY EPTC AND SOME OTHER HERBICIDES
Authors: HAMMERTON J. L. 
Published: July 2006

Summary. Two experiments on chemical weed control in marrowstem kale are reported. In the first of these three herbicides applied before sowing were compared; in the second experiment four herbicides were studied, one applied before sowing and the others applied after emergence. Of all the herbicides examined, EPTC, applied before sowing and incorporated into the seedbed, was the most satisfactory in terms of both weed control and yield of kale. Neither endothal + propham nor dinoseb + TCA proved satisfactory as pre‐sowing treatments. The three herbicides applied post‐emergence (all methylmercapto triazines) were ineffective for the control of Polygonum spp. and Poa annua, although fairly effective against Stellaria media and Chenopodium album. They caused considerable damage to the crop and reduced yields by at least 25%.Le désherbage du chou moellier par l'EPTC et quelques autres herbicides
CHEMICAL INHIBITION OF CROP GERMINATION BY WEED SEEDS AND THE NATURE OF INHIBITION BY ABUTILON THEOPHRASTI
Authors: GRESSEL J. B. , HOLM L. G. 
Published: July 2006

Summary. Aqueous extracts of the ground seeds of thirteen weed species were assayed for their ability to inhibit the germination on filler paper of eight crop species. All of the extracts delayed germination of at least some of the crop species. Germination of some crop species was delayed when the crop seeds were surrounded by weed seeds on filter paper, The seeds of Abutilon theophrasti were inhibitory to tomato (Lycopersicum esculentum) germinated in sterile and non‐sterile soil in the laboratory. The inhibition of germination was apparent under conditions which excluded light, water and minerals as factors in the competition. Chemical studies indicated that the inhibition by Abutilon seeds was due to free amino acids emanating from the seeds. Inhibition chimique de la germination de plantes cultivées par des semences de mauvaises herbes et nature de l'inhibition par Abutilon theophrasti
GENETIC VARIATION IN SIMAZINE RESISTANCE IN WHEAT, RAPE AND MUSTARD
Authors: KARIM A. , BRADSHAW A. D. 
Published: July 2006

Summary. The resistance to simazine of a range of varieties of wheat (Triticum aestivim L.), rape (Brassica napus L.) and mustard (Sinapis alba L.) was assessed in glasshouse tests Varietal differences in survival and final weight of survivors were found in all three crops Variability m the time for which individual plants survived was greatest in the two out‐breeding crops, rape and mustard. The 1 % of mustard plants that survived 10 oz/a csimazine were allowed to produce seed in a polycross. These progenies showed a very marked increase m resistance over the unselected controls.There is thus appreciable genetic variation in resistance to simazine both within and between varieties. This is readily available for selection, and could he valuable in extending the selectivity of herbicides.Variation génétique de la resistance á la simazine chez le blé, le colza et la moutarde
ROOTING CHARACTERISTICS AND VARIETAL TOLERANCE OF SUGARCANE TO DIURON
Authors: And SHENG Y. PENG , YEH HOUNG J. 
Published: July 2006

Summary. The relative susceptibility of six commercial sugarcane varieties to diuron previously described was confirmed in a second similar experiment. A significant correlation was found between the susceptibility of these varieties to 10 kg/ha diuron and their rooting characteristics. The more susceptible varieties were found to produce larger sett‐roots and smaller shoot‐roots, both of which also tended to be more easily injured by diuron. The root injury appeared as‘burnt’root tips resulting from contact with the layer of soil treated by the herbicide. The roots of tolerant varieties seemed to be immune to such injury and continued growing after penetrating the contaminated soil layers. Retarded plant growth appeared to result from the root injury.Uptake of diuron through shoot‐roots of the susceptible variety F 156 resulted in 68·5% growth retardation. This damage was reduced by 15·5% if the plants were allowed to develop sett‐roots from two‐bud cutting. Death of the plant resulted when both root systems received the same dose of herbicide.
THE NATURE AND CONSEQUENCE OF INTERFERENCE BYALOPECURUS MYOSUROIDESHUDS. ON THE GROWTH OF WINTER WHEAT
Authors: NAYLOR ROBERT E. L. 
Published: July 2006

Summary.In a field experiment with different densities ofAlopecurus myosuroides, 10 plants/m2caused no significant reduction in total dry weight of winter wheat at harvest. When autumn‐ or spring‐germinated plants at 100/m2remained until harvest, crop weight was reduced by about 30%. A study of root‐zone competition betweenA. myosuroidesand winter wheat in the glasshouse showed that suppression of the weed by the crop was greater at high nitrogen levels; the practical implications of this are discussed.La nature de l'interférence d'Alopecurus myosuroïdesHuds. sur la croissance du blé d'hiver, et ses conséquences
Differences in the tolerance of metribuzin by varieties of soybeans
Authors: HARDCASTLE W. S. 
Published: July 2006

Summary: Résumé: ZusammenfassungMetribuzin [4‐amino‐6‐tert‐butyl‐3‐(methylthio)‐as‐triazin‐5(4/f)‐one] has shown promise for weed control in Glycine max (L.) Merr. (soybean), but at rates effective for preemergence weed control soybean tolerance has been narrow and field observations indicated that varieties of soybeans differed in their tolerance.Treatments of 0.0,0.56,1,12 and 1,68 kg/ha an location in the Coastal Plain, Piedmont, and Limestone Valley‐area of Georgia indicated that the soybean variety ‘Coker 102’ was Meterially more susceptible to metribuzin injury than were ‘Hardee’, ‘Bragg’, ‘Bienville’, ‘Hampton 266 A’, or ‘Coker 318’. The injury caused smaller soybean stands, heights, and yields. These results confirmed previous observations from field trials using this herbicide. Différences de sensibilités variétales chez le soja vis‐à‐vis de la métribuzine La métribuzine [4‐amino‐6‐tert‐butyl‐3‐(méthylthio)‐as‐triazine‐5(4H)‐one] a donné des résultats prometteurs pour le Désherbage du soja Glycine max (L.) Merr. Aux doses efficacies pour le désherbage en prélevée, la résistance du soja a étéétroite et les observations faites au champ ont mis en évidence des difféarences de sensibilité entre les variétés de soja.Des traitements à raison de 0,0, 0,56, 1,12 et 1,68 kg/ha à des emplacements situfés dans les régions suivantes: Coastal Plain, Piedmont et Limestone Valley, dans l'éatat de Georgie, ont montré que la variété de soja ‘Coker 102’était notablement plus sensible à la métribuzine que les varietés ‘Hardee’, ‘Bragg’, ‘Bienville’, ‘Hampton 266 A’ ou ‘Cocker 318′. Les dégâts se traduisirent par une réduction de Ia vigueur, de lataille et du rendement. Ces résultats confirment les observations antérieures dans des essais au cham pavec cet herbicide.Unterschiede in der Toleranz von Metribuzin gegenüber Sojabohnensorten[4‐Amino‐6‐tert.‐butyl‐3‐(methylthio)‐as‐triazin‐5(4H)‐one] ist ein aussichtsreiches Herbizid für die Unkrautbekämpfung in Glycine max. (L.) Merr. (Sojabohne). Bei wirksamen Aufwandraengen im Vorauflaufverfahren war die Sojabohnentoleranz wenig ausgeprägt und Feldbeobachtungen zeigten, dass Sojabohnensorten unterschiedlich tolerant sind.Behandlungen mit 0,0, 0,56, 1,12 und 1,68 kg/ha an Standorten in der Coastal Plain, Piedmont und der Limestone Valley‐Gegend in Georgia zeigten, dass die Sojabohnensorte ‘Coker 102’ erheblich empfindlicher gegenuber Metribuzinschaden war als ‘Hardee’, ‘Bragg’, ‘Bleinville’, ‘Hampton 266 A’ oder ‘Coker 318′. Der Schaden äusserte sich in geringeren Bestandesdichten, Pflanzenhöhen und niedrigeren Erträgen. Diese Ergebnisse bestätigen die schon früher mit diesem Herbizid gemachten Beobachtungen in Freilandversuchen.
Control of weeds with UHF electromagnetic fields
Authors: WAYLAND J. , MERKLE M. , DAVIS F. , MENGES R. M. , ROBINSON R. 
Published: July 2006

Summary: Résumé: ZusammenfassungUltra‐high frequency (UHF) etectromagnetic energy (2450±20 MHz) was applied for the pre‐emergent and post‐emergent control of weeds. Pre‐emergent tests in the field indicated that energy levels above 70 J/cm2 were required for consistent control. There was no consistent selectivity between broad‐leaved weeds and grasses when pre‐emergent applications were made. Post‐emergent tests indicated that broadleaved weeds were more susceptible than grasses to the UHF energy. Established plants were more susceptible than were seedings of the same species.Lutte contre les mauvaises herbes avec des champs magnétiques a ultra hautes fréquencesUne énergie électromagnétique à ultra haute fréquence (UHF) (2450±20 MhZ.) a été utilisée pour la lutte contre les mauvaises herbcs en pre et en post levee. Des essais au champ en prélevée out montré que des niveaux d'énergie supérieurs à 70 joules:cm2étaient nécessaires pour obtenir des résultats satisfaisants. II n'a pas été constaté de sélectivité entre plantes à feuilles larges et graminées vis‐à‐vis des traitements en prélevée, Les essais en posilevée onl montré que les mauvaises herbes à feuilles larges étaient plus sensibles que les graminées. à I'énergie UHF. Les plantes établies se sont révelées plus sensibles que les plantules des mêmes espéces.Unkrautbekämpfung mit elektromagnetischen UHF‐FeldernElektromagnetische Energie im Bereich der Ultrahochfrequenzen (UHF; 2450±20 MHz) wurde zur Unkrautbekämpfung im Vor‐ und Nachauflaufverfahren eingeseizt. Feldversuche im Vorauflauf zeigten, dass für eine brauchbare Bekämpfung, Energien von über 70 joules/cm2 nötig waren. Die Anwendung im Vorauflauf war zwischen dikotylen Unkräutern und Gräsern nicht selektiv. Versuche im Nachauflaufverfahren zeigten, dass dikotyle Unkräuter gegenüber der UHF‐Energie empfindlicher waren als die Gräser. Von der gleichen Species waren grössere Pflanzen jeweils empfindlicher als die Keimpflanzen.
Ecology and control of blackberry (Rubus fruticosus L. agg.) V. Control by picloram granules*
Authors: AMOK R. L. 
Published: July 2006

Summary: Résumé: ZusammenfassungThe response of blackberry (Rubus fruticosus L. agg.) thickets and of pastures to picloram granules applied in winter or spring was studied in Victoria, Australia.A dose of 10–12 kg ha−1 killed the thickets provided that the litter was no more than 2–3 cm deep. 5·6 kg ha−1 was equally effective if the top growth was mown before the granules were applied. The reason for the greater effectiveness of picloram on mown thickets is not clear, but may involve reduced carbohydrate reserves, reduced dilution of picloram in the roots, or greater accumulation of picloram at sites of meristematic activity.The value of picloram granules for the control of blackberry is discussed in terms of soil residues and cost. Ecologie et destruction des ronces (Rubus fruticosus L. agg.) V. Lutte au moyen du piclorame granulé.La réaction des ronces à l'état de buissons ou dans les pâtures, après traitement au piclorame granulé, appliqué en hiver ou au printemps, a étéétudiée dans l'Etat de Victoria, Australie.Une dose de 10 à 12 kg/ha a détruit les buissons à condition que la litière n'ait pas plus de 2 à 3 cm de profondeur. La dose de 5,6 kg/ha a étéégalement efficace, à condition que les tiges aient été fauchées avant que les granulés n'aient étéépandus. La raison de la meilleure efficacité du piclorame sur les plantes fauchées n'est pas claire, mais il se peut que la fauchaison provoque la réduction des réserves en hydrates de carbone, réduise la dilution du piclorame dans les racines ou provoque une accumulation plus forte de piclorame dans les sites d'activité méristématiques.La valeur des granules de piclorame pour la lutte contre les ronces est discutée en tenant compte desrésidus dans le sol et du prix de revient. Ökologie und Bekämpfung der Brombeere (Rubus fruticosus L. agg.) V. Bekämpfung mit Picloram‐GranulatIn Victoria (Australien), wurde im Winter und im Frühjahr Picloram‐Granulat in Brombeerdickichten und auf Weideland angewendet, um die Wirkung auf die Brombeere (Rubus fruticosus L. agg.) zu untersuchen.10–12 kg ha−1 brachten die Dickichte zum Absterben, vorausgesetzt, dass die Streu nicht stärker als 2–3 cm war. Die gleiche Wirkung wurde mit 5.6 kg ha−1 erzielt, wenn vor der Granulatanwendung die Spitzen der Pflanzen abgemáht wurden. Die Ursache für die bessere Wirkung von Picloram bei den derartig gemähten Dickichten ist unklar. Möglicherweise ist diese Wirkung im Zusammenhang mit verringerten Kohlenhydratrcserven, einer weniger starken Verdüinnung von Picloram in den Wurzeln, oder einer starkeren Anreicher‐ung des Herbizids an Orten meristematischer Aktivität zu sehen.Die Brauchbarkeit von Picloram‐Granular für die Brom‐beerbekämpfung wird unter dem Gesichtspunkt der Rückstände im Boden und der Kosten besprochen.
Cinétique de dissolution dans l'eau de l'atrazine, de la propazine et de la simazine
Authors: CALVET R. , TERCE M. , LERENARD J. 
Published: July 2006

RésuméLa solubitilé et les cinétiques de dissolution dans l'eau de I'atrazine, de la propazine et de la simazine ont étéétudiées à différentes températures. L'ordre apparent des réactions de dissolution est de I pour l'atrazine et la propazine, 2 pour la simazine. La solubilité et les constantes de vitesse sont des fonctions croissantes de la température. Les énergies d'activation de la vitesse de dissolution sont de l'ordre de 4,1 à 4,8 kcal mole‐1. Elles correspondent à une diminution de 30% ilti temps de demie‐réaction pour une augmentation de température de 10°C. II apparaît ainsi que l'eflicacité d'un traitement peut dépendre en partie de l'importanee des pluies et de la température du sol.
A novel approach to Striga and Orobanche control using synthetic germination stimulants
Authors: JOHNSON A. W. , ROSEBERY G. , PARKER C. 
Published: July 2006

Summary:A series of synthetic germination stimulants for the plant parasites Striga and Orobanche has been prepared. These compounds, analogues of the natural Striga germination stimulant, strigol (I), (Cook et al., 1966, 1972) cause signiticant germination of Striga hermonthica (Del.) Benth. seed at concentrations as low as 10−9 M, and an even greater activity against species of Orobanche has been demonstrated. Initial outdoor box trials of the compounds against Striga asiatica (L.) O. Ktze. in Hyderabad, India, have shown a reduction of up to 65% of the seed after a single treatment of the soil 6 weeks before the planting of the sorghum host.