Integrating Fire Risk Considerations in Forest Management Planning in Spain – A Landscape Level Perspective

It is reasonable to assume that there is a relationship between the spatial distribution of forest fuels and fire hazards. Therefore, if fire risk is to be included into numerical forest planning, the spatial distribution of risky and non-risky forest stands should be taken into account. The present study combines a stand-level fire risk model and landscape level optimization to solve forest planning problems in which the fire risk plays an important role. The key point of the method was to calculate forest level fire resistance metrics from stand level indices and use these metrics as objective variables in numerical optimization. This study shows that maximizing different landscape metrics produces very different landscape configurations with respect to the spatial arrangement of resistant and risky stands. The landscapes obtained by maximizing different metrics were tested with a fire spread simulator. These tests suggested that the mean fire resistance of the landscape, which is a non-spatial metric, is the most important factor affecting the burned area. However, spatial landscape metrics that decrease the continuity of fire resistance in the landscape can significantly improve the fire resistance of the landscape when used as additional objective variables.     

Effect of diet and tylosin on chronic diarrhea in beagles

Seven beagles in a colony of dogs had chronic diarrhea for at least 30 days. The dogs were subsequently treated with tylosin 20 mg/kg BW q24h PO for 10 days. During the treatment period, the feces became firmer but remained loose. When the treatment was discontinued, the diarrhea reappeared in 3 weeks. The feces remained abnormally loose in all dogs treated with metronidazole, trimethoprim-sulfadiazine, or doxycycline and prednisone. The diet was then changed for 10 days from a highly digestible moist pet food to a dry food developed for normal adult dogs. The feces again became firmer, although still loose in some dogs. The period was then extended to 3 month, but the fecal consistency continued to fluctuate from ideal to diarrhea. The dogs were treated a 2nd time with tylosin 20 mg/kg BW q24h PO for 10 days. The feces then became significantly firmer and remained so throughout a 3-month follow-up. We conclude that the combination of diet and tylosin was more effective than either agent alone in control of chronic diarrhea.     

Protection of Brucella abortus RB51 revaccinated cows, introduced in a herd with active brucellosis, with presence of atypical humoral response

It is a dogma, that RB51 vaccination does not induce antibodies that interfere with Brucellosis diagnosis, therefore any animal positive to serological test is considered as an infected animal. To determine protection against Brucellosis virulent field strain, 35 pregnant cows from a free-Brucellosis herd, previously vaccinated as calves with 1 x 10(10) CFU of RB51, were revaccinated with RB51 reduced dose, and then introduced into a herd with an active outbreak. Seventeen cows resulted positive in card test after revaccination. All 35 pregnant revaccinated cows had normal parturition; nevertheless, RB51 vaccine strain was isolated from milk and vaginal exudates from two cows after delivery at day 120 post-revaccination. At 150 days post-revaccination, two cows were positives to card and rivanol test and the field virulent strain was isolated. Revaccination with a reduced dose of RB51 in endemic zones did not cause abortion and protected 94% of animals against field infection, but caused an atypical response to conventional serological tests.     

The susceptibility of domestic cats (Felis catus) to experimental infection with Leishmania braziliensis

Over the last few years, several cases of feline leishmaniasis (FL) with cutaneous and visceral forms have been reported around the world. Nonetheless, the real susceptibility of cats to infection with Leishmania spp. and the outcome of leishmaniasis in these animals are poorly understood. Experimental studies on feline models will contribute to the knowledge of natural FL. Thus, in order to determine the susceptibility of domestic cats (Felis catus) to experimental infection with Leishmania braziliensis, 13 stray cats were infected with 10(7) promastigotes by the intradermal route in the ear and nose simultaneously and followed up for 72 weeks. Soon after infection, the earliest indication of a lesion was a papule on the ear at 2 weeks post-infection (w.p.i.). The emergence of satellite papules around the primary lesion was observed about 4 w.p.i. Two weeks later these papules coalesced and formed a huge and irregular nodule. Thereafter, there was lesion dissemination to the external and marginal surface of the ipsilateral ear, and later to the contralateral ear. At 10 w.p.i., some nodules became ulcerated. Nose lesions presented a similar evolution. At both sites, the largest lesion sizes occurred at 10 w.p.i. and started to decrease 15 days later. Ear and nose nodules healed at 32 and 40 w.p.i., respectively. Specific L. braziliensis IgG antibody titers (optical density> or = 0.01 as positive result) were detected as early as 2 w.p.i. (0.09 +/- 0.02) in only three animals (23%), and all cats had positive titers at 20 w.p.i. (0.34 +/- 0.06). Only three animals (38%) continued to show positive serology at 72 w.p.i. (0.08 +/- 0.02). Up to that time, none of the cats had lesion recurrence. In a feline model of cutaneous leishmaniasis, it seems that there is no correlation between active lesions and positive serology. The implications of these data are discussed.     

Is Wolbachia complicating the pathological effects of Dirofilaria immitis infections?

Human and animal parasitic filarial nematodes, which often are the cause of severe disease, harbor intracellular bacteria of the genus Wolbachia (Rickettsiaceae). It is thought that these bacteria play an important role in the pathogenesis and immune response to filarial infection. In order to determine the possible role of Wolbachia in heartworm disease, dogs naturally infected with Dirofilaria immitis were studied for specific antibody response to Wolbachia surface protein (WSP). Antibody subclasses were analyzed to determine immune response polarization. Dogs that died from heartworm disease were necropsied, and various organs were studied by immunohistochemistry to determine whether Wolbachia-derived molecules were present in tissue from infected dogs. Humoral response to the WSP was present in all infected dogs and appeared to be predominantly of the Th1-type. Several organs, including lung, liver, and kidney, contained positive-staining cells for WSP, confirming that the canine host does come into contact with Wolbachia-derived molecules.     

Etude submicroscopique de la structure des reserves nutritives de l'orge

Résumé Dans notre étude submicroscopique des réserves nutritives de l'orge, nous avons pu mettre en évidence d'une façon précise, l'existence des films protéiques longitudinaux et transversaux se trouvant à l'intérieur du grain d'amidon. Un film transversal semble trancher une partie du corps du grain d'amidon, ce qui a été confirmé par l'étude d'une suspension alcoolique (préparée aux Ultra-Sons) et ombragée (métalisée) avec du chrome.Des coupes fines démontrent que les lamelles protéiques sont disposées radialement à l'intérieur des grains d'amidon, et que la structure de l'amidon d'orge est disposée en couches concentriques.Une fissure médiane caractéristique pour les Hordeae a été mise en évidence, ainsi que celle d'une bande pectique à l'intérieur des parois cellulaires. La structure fine de la cellulose en forme de lattice, a pu être ressortie, de même que l'existence de Ponts Intercellulaires avec des Desmosomes.La fixation (OsO₄ suivie de AWP) et l'inclusion dans du methacrylate (buthyl+methyl) 4:1 a été choisie, vu que ce procédé donnait les meilleurs résultats.La fixation avec UO₂ (NO₃)₂ donne aussi de bons résultats, tandis que celle à l'iode doit encore être développée.

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Summary Submicroscopic studies of barley endosperm showed that protein membranes are radialy disposed inside the starch granules. A perpendicular membrane seems to separate a part of the starch granule. The granular consistency of these starch granules has been put into evidence, as well as a medial fissure, caracteristic for Hordeae, well defined.Besides, it was possible to show that the interior of the cell wall consists of a pectic band, and that adjacent cells are connected by intercellular bridges with desmosomes.No great difference was found between fixation with OsO₄ followed by AWP, and the one with H₂ Pt Cl₆.Fixation with uranil nitrate UO₂ (NO₃)₂ was also tried, but the material not yet studied.The fixation with iodide has still to be developped as it is known that iodide, even in dilute concentrations, may form an undesirable coat arround the starch grain.Methacrylate was prefered to araldite, as it can be evaporated under the electronic beam and is well recommended byWykoff (32) andBahr (3). Plexiglas inclusions have still to be tried out.The staining with (O_SO₄+AWP) and evaporation of the inclusion material, gives the possibility to obtain pictures of the cell interior tel quel, which opens new pathways for the future.

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Zusammenfassung Elektronenmikroskopische Studien des Gerstenendosperms zeigten, daß Proteinfilme im Stärkekorn radial gelegen sind. Haftproteine und Lipoproteide konnten besser zur Geltung gebracht werden. Zwickelprotein dagegen nur in einigen Fällen.Ein konzentrischer Aufbau der Stärkekörner, sowie die für die Hordeae charakteristische Medianspalte, wurde nachgewiesen.Es scheint, daß eine Proteinmembran einen Teil der großen Stärkekörner, von der Hauptmasse trennt. Diese Erscheinung konnte außerdem durch Oberflächenstudien hervorgehoben werden.Der Feinbau der Zellwände und das Vorhandensein einer Pektinschicht im Inneren der Zellmembranen konnte durch Fixierung mittels (OsO₄+AWP) und Verdunstung des Methacrylats, hervorgehoben werden.Diese neue Technik erlaubte noch das Vorhandensein von Interzellularbrücken und Desmosomen zu zeigen.Kein großer Unterschied konnte zwischen der Fixierung mit (OsO₄+AWP) und H₂Pt Cl₆, gefunden werden.Wegen Zeitmangel konnte das mit Uranyl-Nitrat UO₂(NO₃)₂ fixierte Material nicht untersucht werden.Methacrylat wurde dem Araldit und Plexiglas als Einbettungsmittel vorgezogen, da es durch Elektronenstrahlen verdampft werden kann.Diese Methode ermöglicht in der Zukunft das Studium der Änderungen, die im Inneren von Zellen durch physikalische und chemische Mittel hervorgerufen werden.

     

Spatial patterns of fire occurrence in Catalonia,NE, Spain

In this paper, we analyse spatial patterns of fire occurrence in Catalonia (NE Spain) during 1975–98. Fire scar maps, discriminated by means of 30–60 m resolution remote sensing imagery, have been used as a source of fire occurrence. We employ several visual or analytical approaches to interpret fire occurrence in this region, such as those of Minnich and Chou (1997), Ricotta et al. (2001) or Krummel et al. (1987). Crucial spatial patterns such as fire size distribution, fire frequency distribution, spots and residual vegetation islands are documented. In addition, several geographical layers were overlaid with burned area maps in order to determine interactions between fire occurrence and environmental parameters such as altitude, slope, solar radiation, and burned land cover. Assuming that fire occurrence is well determined by such a posteriori empirical factors we detect areas most prone to fire in this region and aim to enhance the local forest management and conservation plans.     

Bird assemblages in forest fragments within Mediterranean mosaics created by wild fires

The role of habitat heterogeneity as a key factor in determining species pools in habitat mosaics has been acknowledged, but we still know little on the relative importance of the different ecological processes acting within such complex landscapes. We compared species richness and distribution in forest fragments imbedded in shrub-lands to those in continuous forests or in continuous shrublands. We examined the consistency of our data with the predictions of two hypotheses: 1) the Habitat fragmentation hypothesis which states that fragmentation has negative effects on the species from the original continuous habitat; 2) the Habitat supplementation /complementation hypothesis which stipulates that the presence of a matrix habitat around the fragments will mitigate negative effects on the species from the original habitat (supplementation) or allow the presence of species that depend on the presence of both the fragment and matrix habitats (complementation). We show that: 1) species richness in forest fragments did not differ from species richness in segments of continuous forests of equal area; 2) the bird community of forest fragments got impoverished in some forest species but a higher proportion of species common in continuous forests were not affected by fragmentation; 3) fragment communities had a significant proportion of common species that were scarce in, or absent from both continuous forests and shrublands. While, a few forest species supported predictions from the fragmentation hypothesis, occurrence patterns observed in several other species were consistent with either the supplementation or the complementation hypotheses. Our results suggest that there is no single hypothesis that properly captures the consequences of a shift from continuous forests to a mosaic of forest fragments and shrublands and that different ecological mechanisms act in conjunction to determine species pools in habitat mosaics. Habitat heterogeneity at a local scale appears a key factor in maintaining bird diversity in fire driven Mediterranean landscapes.     

Host-parasite relationships in tobacco plants infected with a root-knot nematode (<Emphasis Type="Italic">Meloidogyne incognita</Emphasis>) population from the Azores

During a nematode survey, severe infections of tobacco feeder roots and heavy soil infestations byMeloidogyne incognita race 1 were found in S. Miguel (Azores islands, Portugal). This is the first record ofM. incognita infection of tobacco in Azores. Morphology of various life stages, analysis of the esterase electrophoretic pattern and differential host tests were used for nematode characterization and identification. Nematode-induced mature galls were spherical and/or ellipsoidal and usually contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode population density and growth of tobacco plants was tested in a glasshouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles (J₂) cm⁻³ of soil. Seinhorst’s model was fitted to height and top fresh weight data of the inoculated and control plants. Tolerance limits with respect to plant height and fresh top weight of tobacco cv. ‘Erzegovina’ plants toM. incognita race 1 were estimated as 1.25 eggs and J₂ cm⁻³ of soil. The maximum nematode reproduction rate was 404.7 at an initial population density of 4 eggs and J₂ cm⁻³ of soil. http://www.phytoparasitica.org posting March 2, 2004.     

Preservation of cadavers for surgical technique training

OBJECTIVE: To evaluate a technique for preservation of organoleptic tissue characteristics (color, odor, texture, and flexibility) in cadavers used for surgical instruction. STUDY DESIGN: Experimental study. ANIMALS: Forty-three canine cadavers. METHODS: Cadavers were preserved with a modified Larssen solution of the Hospital Cochim, Paris and cryopreservation. Tissue handling qualities were evaluated in surgical laboratory sessions. RESULTS: All cadavers kept texture and tissues consistency, especially skin and muscle, similar to those of live animals. Some skin desquamation and pallor of the mucous membranes occurred with repetitive freeze-thaw cycles. CONCLUSIONS: This preservation technique provides acceptable cadaver quality and tissue handling for use in surgical instruction. CLINICAL RELEVANCE: Preparation of patient cadavers by intravascular injection of modified Larssen solution yielded suitable instructional models for surgical training.