Influence of moisture content on the vibrational properties of hematoxylin-impregnated wood

The vibrational property of hematoxylinimpregnated wood was investigated from the aspect of moisture content dependence. The specific dynamic Young's modulus (E/) and loss tangent (tan) of hematoxylin-impregnated wood were determined in the relative humidity (RH) range of 0%–97%, and were compared with those of the untreated and some conventional chemically treated woods. The changes in theE/ and tan of wood with increasing RH were suppressed by acetylation and formaldehyde treatment because of a marked reduction in the hygroscopicity of the wood. Although the hematoxylin impregnation did not significantly affect the hygroscopicity of the wood, its influence onE/ and tan were similar to that of formaldehyde treatment at low RH and of acetylation at medium RH. It was supposed that at low to medium RH hematoxylin restrains the molecular motion of amorphous substances in the cell wall because of its bulkiness and rigidity. On the other hand, at high RH it seems to work as a plasticizer with adsorbed water molecules.     

Working mechanism of adsorbed water on the vibrational properties of wood impregnated with extractives of pernambuco (Guilandina echinata Spreng.)

To clarify the lowering mechanism of loss tangen (tan) of sitka spruce (Picea sitchensis Carr.) wood impregnated with extractives of pernambuco (Guilandina echinata Spreng. synCaesalpinia echinata Lam.), we examined the vibrational properties of the impregnated wood in relation to the adsorbed water. The results obtained were as follows: (1) The equilibrium moisture content (EMC) of impregnated sitka spruce decreased to some extent compared with untreated wood. (2) Frequency dependencies of tan a about 400–8000Hz showed that impregnated wood has much lower tan than untreated wood at around 9% mois ture content (MC), except for the high-frequency region. At high relative humidity, impregnated wood has a minimum tan (at around 4000Hz); and at other frequency ranges the tan of impregnated wood did not differ considerably from that of untreated wood. (3) The apparent activation energy of the mechanical relaxation process (E) concerned with adsorbed water molecules was higher for impregnated specimens than for untreated ones at moderately high relative humidity, whereas at high relative humidity the difference was not observed. Based on these results, it is thought that the tan of impregnated wood decreased at low rela tive humidity because of the formation of direct hydrogen bonds between impregnated extractives and wood components. However, when the specimen is at higher relativePart of this work was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998 humidity, the formation of direct hydrogen bonds are disturbed by the existence of a large number of water molecules, and some extractives act as a plasticizer.     

Non-steady state water adsorption of wood

Summary The validity of the following equation of water adsorption into wood substance which was derived in the previous report, is examined: d(W)/dt = k₀(1 – exp(-k₁/t))W(l – W), which can approximately be written as: d(W)/d(logt) = rW(l – W), where W is moisture content; t is time (t > 0); k₀, k₁ and r are constants. After measuring dimensional change with change in time under various relative humidities, the change of moisture content was indirectly calculated from the proportional relationship between dimensional change and moisture content. It was found that the theoretical equation satisfactorily agreed with the experimental results. These results lead to the conclusion that the equation was valid. Furthermore, the properties of the equation, whose constants are determined from experimental results, is discussed. The rate of water adsorption of wood shows interesting and systematical properties, especially near relative humidities corresponding to the fiber-saturation point.     

Modelling the long-term strength of timber columns

Summary This paper studies the influence of the used creep function, and the duration of the experimental sustained loading from which the creep function was derived, in modelling the long-term buckling strength of timber columns. The sensitivity of this buckling strength to creep and initial deflection is numerically studied using an energy approach that takes into account the initial deflection. Various creep functions — power laws as well as exponential laws — derived from bending experiments of different durations are used for the numerical simulation. The crucial need for experimental results issued from very long load period experiments is identified. Such experiments may lead to a more credible creep analysis of timber structures.Symbols i radius of giration - s stress level - E_L effective MOE - E₀ instantaneous MOE - I inertia moment - K,K geometrical matrices - L length of beam or column - L_f effective length - N_cr axial force, buckling load - U elastic strain energy - W external forces work - t time variable - u moisture content (m.c.) - v total deflection - v_c, v_e, v₀ creep, instantaneous elastic and initial deflections respectively Greek Letters (t) time function - , _e, ₀ total, instantaneous and initial strains respectively - twist rotation - (t) creep coefficient or fractional creep or relative creep - (x) shape function - load factor - longitudinal shortening - total potential energy - creep factor - relaxation time     

Die Massenvermehrung des Hagebuchenspanners,Himera pennaria L., 1962 in Niederösterreich und im Burgenland und die Ursachen des Zusammenbruches der Kalamität

Summary The Outbreak of Himera pennaria L. in 1962, in Lower Austria and Burgenland, and Causes of its break-down.The Hornbeam Measuring Worm,Himera pennaria L., hitherto described but once in forest-entomological literature as a bigscale forest pest, performed mass-attacks in 1962 in the Leitha hills (1500 acres) and Maria-Ellend wood, even clean-eating several hardwood species, especially hornbeam and also oak. The outbreak which occurred about mid-May broke perfectly down as soon as early June. The paper characterizes several bionomical and morphological data obtained during the course of the outbreak from individual development stages, also discussing the possible causes of the outbreak illustrated by climatograms. In conclusion, the biotical factors of the breakdown are treated, pointing out a virus disease (cytoplasmic polyhedrosis of mesenteron) as playing the greatest part. Along withH. pennaria L., alsoHibernia defoliaria L.,Hibernia aurantiaria Esp., andCheimatobia brumata L., as well as 4 species ofNoctuidae and 1 species ofArctiidae occurred rather frequently in the above-mentioned area, especially in the marginal zones of the Hornbeam Measuring Worm's mass-attack.

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Résumé La gradation de l'Arpenteuse du Charme —Himera pennaria L. — en 1962, en Basse-Autriche et au Burgenland, et les causes de la débâcle de la calamité.L'Arpenteuse du Charme,Himera pennaria L., signalée une seule fois dans la litérature entomologique forestière comme ravageur en masse, s'est manifestée en dimensions calamiteuses en 1962, dans les montagnes du Leitha (600 ha) et au bois de Maria- Ellend, dépouillant — par endroits même de leur feullage eiitier — différentes espèces de bois feuillus, surtout des charmes mais aussi des chênes. La gradation qui s'était manifestée vers la mi-mai, subit une débacle complète dès le début de juin. Le mémoire présente quelques données bionomiques et morphologigues, obtenues au cours de la gradation, sur les différentes phases du développement, tout en discutant à l'aide de climatogrammes quelles pourraient être les causes de la gradation. En conclusion, on traite spécialement les facteurs biotiques de la débâcle, parmi lesquels une maladie à virus (polyédrose cytoplasmique du mésentère) a joué le premier rôle. Em même temps que l'Himera pennaria L., les insectes suivants ont été trouvés dans le territoire en question, le plus fréquemment dans les zones marginales de l'aire de grádation de l'Arpenteuse du Charme:Hibernia defoliaria L.,Hibernia aurantiaria Esp.,Cheimatobia brumata. L., 4 espèces de Noctuides et l espéce d'Arcttides.

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Himera pennaria L. 1962 . . . . ,Himera pennaria L., -- , 1962 . (600 .) , , . , , . , , , . , ( ). H. Pennaria L. Hiberia defoliaria L., Hibernia aurantiaria Esp., Cheimatobia brumata L., 4 Noctuidade 1 Arctiidae, .

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Herrn Prof. Dr. A. Acatay zum 60. Geburtstag gewidmet.

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Die Untersuchungen erfolgten in Zusammenarbeit mit der Landesforstinspektion für Niederösterreich, speziell mit der Bezirksforstinspektion Wien-Umgebung und der Landesforstinspektion für das Burgenland, wofür an dieser Stelle herzlichst gedankt sei.

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Für Herstellung der mikroskopischen Präparate sei Frl. H. Meldt, für die Freilandaufnahmen und mikroskopischen Aufnahmen Herrn N. Maisner bzw. Herrn O. Baschny der Forstlichen Bundesversuchsanstalt Mariabrunn, für die Aufnahmen der elektronen-mikroskopischen Präparate Herrn Hayek vom Physikalisch-chemischen Institut der Universität Innsbruck gedankt.     

Estimation of evaporation rate from the forest floor using oxygen-18 and deuterium compositions of throughfall and stream water during a non-storm runoff period

Rainwater, throughfall, stream water during a non-storm runoff period, and soil water were sampled about every 10 days at six nested basins within the Hitachi Ohta Experimental Watershed in Japan from 1998 to 2001. Basins HA and HB are covered with an 80-year-old artificial forest of Japanese cypress and Japanese cedar. HC and HV are covered with 12-year-old forest of the same species. HO and HX are covered with various aged stands of the same species. The samples were analyzed for the isotopic compositions of ¹⁸O and deuterium (D). The weighted means of ¹⁸O (D) in HA and HB were –7.35 (–46.7) and –7.38 (–46.8), while they were –7.51 (–48.1) and –7.57 (n/a) in HC and HV, respectively. They were –7.50 (–47.6) and –7.41 (–47.1) in HO and HX, respectively. There was a relative difference of 0.2 (1.4) in ¹⁸O (D) between 80-year-old and 12-year-old forest. The stream water during a non-storm runoff period is considered to reflect the effect of evaporation from the forest floor. The evaporation rates from the forest floor were estimated using values in throughfall and stream water using the Rayleigh distillation equation under equilibrium conditions. They were estimated to be 5.5 (9.1), 5.2 (9.0), and 4.9 (8.7)% of annual throughfall in HA, HB, and HX (mature forests), respectively, using ¹⁸O (D), and 4.0 (7.6), 4.1 (8.1), and 3.5 (n/a)% of annual throughfall in HC, HO, and HV (young forests), respectively.     

Effects of quenching on relaxation properties of wet wood

A new relaxation property is discussed on the basis of creep behavior of wet wood specimens pretreated with heating at various temperatures followed by quenching. The treated samples showed more marked relaxation than that of an untreated sample. The relationship between relaxation time and heating history was represented by an equation ln() = –( _f – k ₁)T + [ln( _g) + k ₂], where ln() is the logarithmic relaxation time of wet samples after quenching, T is the difference between the heating temperature and the glass transition temperature (T _g), ln( _g) is the logarithmic relaxation time at T _g, is a constant, _f is the coefficient of thermal bulk expansion, and k ₁ and k ₂ are constants. It was concluded from the analysis of experimental results that the change in the relaxation property caused by heating and the following quenching is due to the temporary free volume created by freezing of molecular chain motion of wood components, most probably lignin, during quenching.This work was presented at the 52nd Annual Meeting of Japan Wood Research Society, Gifu, April 2002     

Absolute configuration of arylglycerol-β-aryl ethers obtained by asymmetric reduction of the correspondingα-ketonic compound with intactFusarium solani cells

When (±)--oxo-guaiacylglycerol--(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the-ketone is initially reduced to giveerythro andthreo guaiacylglycerol--(vanillic acid) ethers (2), arylglycerol--aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to,-di-(R)--methoxy--trifluoromethylphenylacetates (MTPA esters) (3) oferythro (-)- andthreo (+)-veratrylglycerol--(methyl vanillate) ethers (3), whose¹H nuclear magnetic resonance (NMR) spectra were examined and compared with those of four di-(R)-MTPA ester (3) diastereomers from chemically synthesizederythro (±)-3 andthreo (±)-3. To assign the- and-MTPA-OCH₃ peaks, the¹H NMR scans of several compounds that have substructures of 3 and their 3,4,5-trimethoxyphenyl analogues were examined. When a racemic alcohol reacts with (R)-MTPA to give a pair of (R)-MTPA ester diastereomers, the value was defined as the absolute value of the difference in the¹H chemical shifts of the peak between the diastereomers. It was found that the values of-MTPA-OCH₃ were larger than those of-MTPA-OCH₃ owing to a shielding effect of the veratryl ring located on the-MTPA-OCH₃, and that the-MTPA-OCH₃ peaks in the 3,4,5-trimethoxyphenyl compounds shifted downfield relative to those in the veratryl compounds. On the basis of the¹h NMR data of (R)-MTPA esters, the absolute configuration of the four chemically prepared diastereomers (3) were determined. The catabolicerythro 3 [fromerythro (-)-3] andthreo 3 [fromthreo (+)-3] were identical to (R, S, R)-erythro 3 and (R, S, S)- threo 3, respectively. An hydrogen species in the fungal reduction would attack the-ketone fromre-face of both (R)-1 and (S)-1, givingerythro (S, R)-2 andthreo (S, S)-2, respectively.Part of this paper was presented at the 33rd Lignin Symposium, Tsukuba, November 1988     

Controlling the timbre of wooden musical instruments by chemical modification

Summary A method to control the tone quality of wooden string instruments by chemical modification is proposed. Sitka spruce specimens impregnated with saligenin solutions of various concentrations were allowed to react with gaseous formaldehyde using SO₂ as a catalyst. In the frequency range where shearing deformation is negligible, the values of specific dynamic Young's modulus (E/) in the radial direction increased with increasing saligenin concentration by up to 27%, whereas the values of dynamic loss tangent (tan ) decreased as much as 40% in the longitudinal direction and 50% in the radial direction along with small increases in air-dry specific gravity. The degree of increase of tan with increasing frequency was inversely proportional to the saligenin content. The frequency dependence of E/ did not change as a result of treatment. From these results, it is considered that the sound level radiated from wooden string instruments changes at high frequencies according to the saligenin content.     

Vibrational property changes of spruce wood by impregnation with watersoluble extractives of pernambuco (Guilandina echinata Spreng.) II: structural analysis of extractive components

Heartwood of pernambuco (Guilandina echinata Spreng, synCaesalpinia echinata Lam.), which has been used as material for violin bows, was extracted by soaking in water, and the obtained extractives were analyzed. The main components of the extractives were identified to be protosappanin B and brazilin. In particular, protosappanin B occupied about 40% of the pernambuco extractives. The loss tangent (tan) of spruce wood impregnated with protosappanin B decreased markedly, the same as that of specimens impregnated with extractives before being purified. It is expected that protosappanin B can make a contribution to the decrease in tan due to impregnation with extractives.Part of this work was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998; and the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 1999     

Inhibition ofTrichoderma cellulase activity by a stilbene glucoside fromPicea glehnii bark

The stilbene glucoside isorhapontin (5,4-dihydroxy-3-methoxystilbene-3--D-glucoside) is the major constituent of the ethyl acetate extracts fromPicea glehnii bark. Isorhapontin inhibited the hydrolytic activity ofTrichoderma cellobiohydrolase I (CBH I) for both bacterial microcrystalline cellulose and the soluble cellooligosaccharide celloheptaitol. The inhibitory effect for celloheptaitol, however, was more drastic than that for bacterial microcrystalline cellulose. The hydrolytic activity of the CBH I core domain for celloheptaitol was also inhibited by isorhapontin to a similar extent, suggesting that the interaction between isorhapontin and the core domain of CBH I is the reason for this phenomenon. The inhibition of CBH I activity by isorhapontin showed mixed noncompetitive and uncompetitive types in a concentration of the inhibitor of less than 125M. TheK _i andK _i values were estimated to be 57.2 and 33.3M, respectively. Whereas isorhapontin strongly inhibited CBH I activity, its aglycone isorhapontigenin (3-methoxy-3,5,4-trihydroxystilbene) showed almost no inhibition. Consequently, both the stilbenic and the-glucosidic structures in isorhapontin are essential for the inhibitory effect on CBH I activity. Isorhapontin also inhibited the activity ofTrichoderma endoglucanase I for celloheptaitol, whereas almost no effect was observed for the activities of both endoglucanases II and III.An outline of this work was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999     

Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,Australia

Aboveground and belowground root biomasses (Babove and Broot) were measured for young, isolated Rhizophorastylosa on Iriomote Island, Japan. The relationship between these two parameters was significant and given as the equation, Broot(g dry weight) = 0.394 × Babove(g dry weight) – 485 (r = 0.986). Multiple regression analyses also revealed good correlation between diameter and biomass of prop roots (Dprop and Bprop) and between prop root and root biomasses. Consequently, root biomass could be estimated from the measurements of diameter and biomass of prop roots using the multiple regression equation, Broot(g dry weight) = 80.0 ×Dprop(cm) + 0.86 ×Bprop (g dry weight) – 251. The relationship between DBH (diameter at breast height) and prop root biomass was also adequately described using an allometric equation.In Hinchinbrook Channel, Australia, redox potential (measured as Eh) and organic carbon stocks in the top 5cm of mangrove sediments were measured along a 600m transect from the frequently inundated, Rhizophora dominated zone on the creek edge, towards higher grounds, where Ceriops spp. became increasingly dominant. Eh values were about –60mV near the creek edge and increased to 260mV on higher grounds. Organic carbon stocks showed an opposite trend to Eh, with the values decreasing from about 360tCha–1 to 160tCha–1. At 18 sites, representing six different habitats, organic carbon stocks were also measured along with the DBH of mangrove trees. DBH was converted into aboveground biomass and then into root biomass using the equations obtained in the study on Iriomote Island. The average organic carbon stocks in the top 50 cm of sediments, aboveground biomass and root biomass were 296tCha–1, 123 tCha–1 and 52 tCha–1, respectively, and accounted for 64%, 25% and 11% of the total organic carbon stock.     

Holzangriff durch Larven der AmpferblattwespeAmetastegia glabrata Fall.(Hym., Tenthredinidae)

Zusammenfassung Die Altlarven 2. Generation der AmpferblattwespeAmetastegia glabrata Fall. sind im Obstbau als Schädling bekannt. Die Schäden entstehen bei dem Versuch der Larven, in Früchten Puppenkammern anzulegen.Üblicherweise verpuppen sich die Larven in den trockenen Stengeln der Nährpflanzen(Polygonaceae) oder anderem trockenem oder verholzten Pflanzenmaterial.Es wird über einen gesicherten Fall berichtet, in demAmetastegia glabrata-Larven in verarbeitetem Nutzholz (Plakattafel) schädlich geworden sind. Ein weiterer Fall konnte nicht völlig geklärt werden; jedoch waren auch hier Blaltwespen-Larven in einer Wohnung in verarbeitetes Nutzholz (Türrahmen) eingedrungen.Nach dem geringen Umfang der Schäden, die nur durch die Anlage kurzer Puppenkammern in weichen Holzteilen entstehen, istAmetastegia glabrata in die Gruppe der gelegentlichen Holzzerstörer einzureihen. Allerdings kann durch diese Art völlig gesundes Holz im Freiland angegriffen werden.Holzschutzsalze vom U-Typ genügen zur Vorbeugung nicht. Vorbeugungs- und Bekämpfungsmaßnahmen werden besprochen.

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Summary Attack on wood by larvae of the dock sawfly Ametastegia glabiata Fall. (Hym., Tenthiedinidae) Normally the mature larvae of the last brood of the dock sawfly bore themselves for pupation into dry stems of plants.By the gnawing efforts in certain years of appearance in masses, however, they may attack fruit too, especially apples, and cause considerable damage by numerous gnawing spots.Besides these known injuries on fruitA. glabrata has now been stated in two cases as an occasionally dangerous animal to dry timber too.The damage caused is described by word and picture; preventive and curative measures are discussed.

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Résumé Attaque du bois par des larves de la Tenthrenidé Ametastegia glabrata Fall. (Hym., Tenthredinidae) Normalment les larves adultes de l'A. glabrata se forent dans les tiges sèches des plantes pour la mé tamorphose.Cependant aussi des fruits, surtout des pommes, sont attaqués par le ronger pendant les anées quand ces insectes paraîssent en masse. Des dommages considérables sont provoqués aux points d'attaque nombreux.A côté de ces dommages connus aux fruits l'A. glabrata a été constaté en deux cas comme causeur de dommage par occasion en bois sec de construction.Les dommages sont décrits et figurés; des methodes preventives et curatives sont discutées.

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? Ametastegia glabrata Fall. (Hym., Tenthredinidae) . , , , . Ametastegia glabrata Fall. ( ) . , .

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Mitteilung aus dem Holzschutzlaboratorium der Farbenfabriken Bayer AG., Werb Uerdingen     

Zur Wirkung von Sevin auf Regenwürmer

Zusammenfassung In Freiland- und Laborversuchen wurde die Wirkung des Pflanzenschutzmittels Sevin auf Regenwürmer untersucht. Dieser Stoff ist in Pulverform und als Suspension für diese Organismen außerordentlich gefährlich. Schon der Kontakt mit sehr geringen Mengen bewirkt schwere Lähmungserscheinungen und irreversible histopathologische Schäden.

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Summary Experiments in the field as well as in the laboratory showed up the effect of the pesticide Sevin on rainworms. In the form of powder as well as a suspension this material is extremely toxic for them. Contact with smallest quantities even causes severe paralysis and irreversible histopathologic damages.

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Résumé Aussi bien dans la nature que au laboratoire nous avons étudié l'activité de l'insecticide Sevin sur les vers de terre. Ce produit est en poudre ou en suspension extrémement dangereux pour ces organismes. Le seul contact avec des quantités minimes de ce produit provoquent des phénomènes de paralysie et des troubles histopathologiques irreversibles.

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SEVIN . . .

     

Preparation of liquid polyesterpolyols from glucose and its methyl derivative

Preparation of liquid polyols from d-(+)-glucose (Glc) and its derivative, methyl--d-glucoside (m-Glc), has been studied. Direct reaction of -caprolactone (CL) with Glc (CL:Glc = 2:1–5:1 in weight ratio) at 150°C using tin(II) 2-ethyl hexanoate (SnEht₂) (series A), in which melted Glc was suspended in CL, resulted in a dark-brown coloration of the reactants. The reaction was accompanied by formation of high molecular weight resins, a pH drop, production of water, and a considerable decrease in the hydroxyl value from the theoretically expected one. In the case of Glc/ethylene glycol (EG)/CL reaction system with SnEht₂ catalyst at 150°C (series B), in which the weight ratio of Glc to EG was fixed at 1:1, Glc dissolved in the EG/CL mixture, but the brown coloration of the reactant mixture still occurred. In this case, the formation of water was enhanced, but the other effects found in series A were suppressed to a considerable extent. In the m-Glc/CL/SnEht₂ reaction system (series C), in which m-Glc reacted with two to five times weight amounts of CL under the same conditions adopted in series A, development of the color, the production of high molecular weight materials and water, and the changes in pH and hydroxyl value were not observed. These results are discussed based on the chemical structural differences: Glc exists mostly in the hemiacetal form, but tautomerizes to the aldehyde, whereas m-Glc is an acetal and is protected from reversion to the aldehyde.     

Structure of xylan from culms of bamboo grass (Sasa senanensis Rehd.)

Xylan prepared from culms of kumaizasa (Sasa senanensis Rehd.), a representative species of bamboo grass, was hydrolyzed with-xylanase ofStreptomyces olivaceoviridis E-86. Four arabinoxylo-oligosaccharides and two glucuronoxylo-oligosaccharides were isolated from the enzymatic hydrolysate of the xylan by chromatography on a charcoal column, a Dowex 1-x8 column, a Toyo-pearl HW-40S column, and a LiChrospher 100 NH₂ column and on preparative paper chromatography. The results of the structural analyses of the saccharides showed that the isolated oligosaccharides had the structures of 3²--l-arabinofuranosyl-xylobiose, 3²--l-arabinofuranosyl-xylotriose, 3²--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylobiose, 3³--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylotriose, 2³--4-O-methyl-d-glucuronosyl-xylotriose, and 2³--d-glucuronosyl-xylotriose. From the structural analysis of the oligosaccharides derived from the xylan, kumaizasa xylan was concluded to be a kind of arabinoglucuronoxylan having not only stubs of singlel-arabinose and singled-glucuronic acid but also stubs of disaccharide units such as-d-xylopyranosyl-(1 2)-l-arabinofuranose.     

Richtungen der angewandten Entomologie in Bulgarien

Summary For protection of agricultural crops, archards, forests and stored products a system of institutes for vegetative protection have been gradually built in Bulgaria within the last fifteen years. Now a leading part in the study of pests and diseases of plants are taking the Academy of Rural Economy Sciences and the Institutes for Plant Protection, for Forest Protection, the Zoological Institute by the Bulgarian Academy of Science, the Higher Rural Economy Institute and the Higher Forest Institute. Specialists of all ranks are working at these institutes: academicians, member correspondents, professors, senior and junior scientific collaborators and a great number of experts and assistants. Parallel with the studies of specific composition of pestilent insects, their biology is being explored and experiments are being made with insecticides. An inquiry is also being undertaken for utilization biologic combat against noxious insects. In aid of scientific institutes a dense network of services for heading the research work and combat on the terrain has been organized.

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Résumé Pour la défense des cultures agricoles, des vergers, des forêts et des produits récoltés, un système d'instituts pour la défense végétale a été successivement dé veloppé en Bulgarie pendant les dernières quinze années. Actuellement l'Academie des sciences de l'economie rurale et les Instituts pour la défense végétale ont le rôle dirigeant dans les recherches de la nocivité et des maladies sur les plantes. Dans ces instituts travaillent des spécialistes de toutes les catégories scientifiques: des académiciens, des membres-correspondants, des professeurs, des travailleurs scientifiques supérieurs et plus jeunes, avec un grand nombre d'aides-spécialistes. Parallèllement à l'étude de composition specifique des insectes nuisibles on étudie sa biologie, de même on fait des expériences avec des insecticides. Aussi on cherche à utiliser la lutte biologique contre les insectes nuisibles. Pour faciliter les instituts scientifiques dans cette lutte et leur recherche sur le terrain, un immense service est organisé dans tous les plus grands emplacements peuplés du pays.

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. , 15 , , , . . - , , , . - , , - . : , , , . , . . , . - , . .

     

Nahrungsaufnahme und Natalität bei palaearktischen Simuliiden (Diptera) 1. Blutfütterung vonBoophthora erythrocephala De Geer 1776 undWilhelmia lineata Meigen 1804 am Kaninchen

Zusammenfassung Während mehrer r Monate wurden Weibchen vonBoophthora erythrocephala undWilhelmia lineata am Kaninchenohr gefüttert und die Überlebensrate während der Eireifungsphase,

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Nutrition and Reproduction in Palaearctic Blackflies (Simuliidae: Diptera). I. Bloodfeeding ofBoophthora erythrocephala De Geer andWilhelmia lineata Meigen on RabbitsFemales of the mammalophilic species,Boophthora erythrocephala andWilhelmia lineata, feed on cattle and horses in the field. When fed on the rabbit's ear under laboratory conditions, they differ considerably in bloodsucking activity, in mortality during digestion of blood, natality, and hatching rates of first instar larvae. InB. erythrocephala 641 wild-caught- fed in 74,1% without seasonal variation. When females were kept up to four days before feeding their bloodsucking activity did not decrease. Laboratory-emerged- usually fed in even higher rates (416/533) and 4–6 days old flies fed more frequently than younger or older females. Survival rates during digestion of blood in 4 days were 60% in wild-caught, 40% in laboratory-emerged-, and 74% in cattle-fed-. Only 29% of wild-caught and the cattle-fed- but 50% of the laboratory-emerged flies could be induced to lay eggs on wet substrate. Natality of cattle- (219 eggs/) and laboratory-emerged fed on the rabbit (225 eggs/) were significantly higher than in wild-caught rabbit-fed- (191 eggs/). The number of eggs developing to first instar larvae generally was low (42%). InW. lineata wild-caught- fed less successfully (162/407) and showed considerable seasonal variation. The best results were obtained in September and October. Keeping them in the laboratory for 1–4 days reduced the bloodsucking activity. In laboratory-emerged- the best feeding result (347/724) were obtained with 4–6 day old flies but their survival during maturation of eggs remained low (55%). It was higher with wild-caught (67%) and cattle-fed- (78%). In all cases 60% of them could be induced to oviposit. The rabbit-fed wildcaught or laboratory-emerged flies produced significantly more eggs (183 resp. 197 eggs/) than cattle-fed ones (138 eggs/). Most egg batches contained only 16% fertilized eggs. In laboratory-emerged- ofB. erythrocephala andW. lineata the potential natality was highest in spring, lowest in summer and increased again in autumn. The number of eggs/ was affected by the blood volume. Starting with laboratory-emerged flies fed on the rabbit a production factor of 10.9 is calculated forB. erythrocephala and of 5.4 forW. lineata rearing from the imago to the first instar larva. When the larvae are reated to adults with 44% efficiency a reproduction of 2.4 resp. 1.2 per generation of females results.

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Mit 4 Abbildungen und 4 Tabellen     

Versuche zur Bekämpfung der ObstbaumspinnmilbePanonychus ulmi Koch im Libanon

Summary During the application of several acaricides to manifest their effectivness againstPanonychus ulmi Koch living on the apple trees in Lebanon, it could be clearly noticed that a kind of resistance to the phosphoric acid organic preparations occurs, where these mentioned chemicals are regularly used against the mites. The control succes by means of some acaricides and ovicides combinations is here discussed. AsTetranychus urticae Koch in some apple plantations infests the different weeds growing together with the trees there and it wanders in summer to overrun the apple trees; the question of the mite control by means of respective sprays or by means of weed eradication is also discussed.

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Résumé L'étude de l'efficacité d'une série d'acaricides dePanonychus ulmi Koch sur pomme en Liban a démontré une certaine résistance de groupes des parathions, lá où ceux — ci sont appliqués régulièrement depuis des années. Les résultats de combat de quelques acaricides et combinaisons par des ovicides sont discutés. PuisqueTetranychus urticae Koch occupe les herbes, les plus différentes, et depuis — là en été change sur les pommiers la question d'un combat de cet acarien nuisible par des application ultérieures ou par l'extermination d'herbes est discuté e.

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, Pannonychus ulmi Phosphorsäureester. Akarizide Ovizide. Tetranychus urticae , .

     

Reaktionen der Kiefernrinden-Wanze (Aradus cinnamomeus Panz.) auf die Terpemoide

Zusammenfassung In dem für die Besonderheiten der Kiefernrindenwanze konstruierten Olfaktometer, wurden die Chemotaxie des Schädlings auf die Terpenoide aus ätherischen Ölen der Gemeinen Kiefer untersucht. Es wurden dabei Terpenoide mit vorwiegend anlockender und abschreckender Wirkung isoliert. Einige Terpenoide (-Pinen und Limonen) verwandeln bei einer Änderung ihrer Konzentration ihre anlockenden Eigenschaften in abschreckende. Bei der Verdampfung von der Oberfläche der pflanzlichen Gewebe der Kiefer bilden die Terpenoide eine Schutzwolke — ein äußeres Schutzsystem (R-System). Bei Überwiegen der anlockenden Stoffe wird in den Dä mpfen der wirksamen Stoffe das System lockend (A-System). Es wurde ein Modell des äußeren Systems aufgebaut und ihre ungefähre mathematische Erklärung gebracht, die erlaubt, die Anlockung der pflanzlichen Gewebe der Kiefer für die Rindenwanze nach den Ergebnissen der chromatographischen Analyse der atherischen Öle zu ermitteln. Das äußere Schutzsystem der Kiefer ist eines von den Systemkomplexen, welches als Schutzfunktion die Widerstandfähigkeit der Kiefer gegen Schadinsekten erfüllt und gewährleistet.

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