bluuebunny/crossref_metadata_2025 huggingface dataset:
Population dynamics of Paratylenchus nanus in soil under pasture: 2. Biotic factors and population modelling
Authors: Watson Richard , Bell Nigel
Published: January 2003

Seasonal and monthly sampling of a Paratylenchus nanus population showed that trends in biomass were similar to those for abundance. A Population Age Index (proportional contribution of each life stage multiplied by stage biomass) showed population age increased from a minimum in spring to maximum in winter. From mid-spring to mid-summer, population age was greater in 0-10 than 10-20 cm depth; this may have been due to a greater proportion of juveniles developing over this period at the deeper depth. The populations at 10-20 cm deep included a greater proportion of fourth stage juveniles than those at 0-10 cm. This may reflect the smaller root resource at 10-20 cm depth limiting population development. Monthly sampling of patches of high vs low P.nanus density indicated that such patches retain their densities relative to each other in most months. Evidence is presented for density-dependence in the P. nanus population at 0-10 cm and density-independence at 10-20 cm depth. Multiple regression models were fitted, taking into account all factors (abiotic and biotic) which were significantly associated with P.nanus abundance, and results are discussed to highlight areas still requiring investigation before a complete model of the population dynamics of this nematode can be achieved.
Dynamics of sympatric Paratylenchus nanus and Paratrichodorus minor populations in soil under pasture
Authors: Watson Richard , Bell Nigel
Published: January 2003

Populations of both Paratrichodorus minor and Paratylenchus nanus in a grazed pasture in Waikato, New Zealand were assessed in single 2.5 cm diam. core samples over six successive seasons. Neither seasonal periodicity nor a consistent vertical distribution pattern was observed in the P.minor population. P.nanus had distinct spring and summer population maxima and was more abundant at 0-10 than 10-20 cm depth. P.minor but not P.nanus abundance was significantly correlated with rainfall and an activity index combining rainfall and soil temperature for the week before sampling. Significant correlations among P.minor, P.nanus and concentrations of some soil nutrients seemed to reflect soil nutrient interactions with other biotic factors such as plant growth. There was no evidence for competition between these two nematodes. Host root resource, spatial aggregation and differences in morphology that indicate niche differences are discussed as possible reasons for the observed lack of competition.
Trichodoridae (Nematoda: Triplonchida) in Spain
Authors: Arias María , López-Pérez Antonio , Bello Antonio
Published: January 2003

A revision has been made of the Trichodoridae family in Spain. Seventy records were determined or confirmed. Reports of Paratrichodorus cf. acutus (one record) and 24 of Trichodorus species were not confirmed and those of eight species were regarded as erroneous. Thirteen species have been found in Spain, five belonging to the genus Paratrichodorus (P.anemones, P.hispanus, P.minor, P.pachydermus, P.teres) and eight to Trichodorus (T. beirensis, T. cylindricus, T. giennensis, T. lusitanicus, T. primitivus, T. similis, T. sparsus, T. viruliferus). P.minor and P.teres appeared in the Canary Islands. No trichodorids have been reported on the Balearic Islands. T.lusitanicus is a new species for Spain and 33 records are new.
Laboratory culture of two Xiphinema americanum-group species (Nematoda: Longidoridae) from Senegal
Authors: Baujard Pierre , Diop Mamadou , Mounport Danamou , Diémé Jacques-Hubert
Published: January 2003

Two Xiphinema americanum-group species from Senegal were successfully cultured on plants in the laboratory and the effects of host plant, temperature and soil moisture were evaluated. Soil temperature had most effect while soil moisture had no effect on multiplication. Greatest reproduction rates were observed for one species on Pennisetum typhoides (millet) and for the other species on Sorghum vulgare. These two gramineous species were better hosts than the legumes Vigna unguiculata (cowpea) and Arachis hypogaea (peanut). Multiplication was greater when plants were inoculated with freshly extracted nematodes.
Cryopreservation and low temperature storage of the pre-parasitic juveniles of Romanomermis culicivorax
Authors: Platzer Edward , Peng Yufang , Song Jinzhang , Song Yi
Published: January 2003

The effects of low temperature storage and cryopreservation on the survival and infectivity of Romanomermis culicivorax were studied in the laboratory. When pre-parasitic juveniles of R. culicivorax were stored at-2 to 2°C, more than 90% survived for 9 days and 50% were motile for 13 days. The infective ability of the pre-parasitic juveniles for mosquitoes remained high (85%) after 5 days of cold storage and the infectivity was reduced only moderately (50 to 78%) after storage for 6 to 10 days. Various cryoprotectants were investigated to develop a cryopreservation procedure for the infectious pre-parasitic juveniles of R. culicivorax. After suspension in 1, 2.5 or 5% dimethylsulphoxide (DMSO), and cryopreservation with a two-step cooling sequence prior to storage in liquid nitrogen, approximately half of the pre-parasitic juveniles of R. culicivorax, cryopreserved in 2.5 and 5% DMSO, regained motility when thawed quickly after storage for 7 and 125 days. However, revived pre-parasitic juveniles were unable to infect mosquito larvae. Pre-parasitic juveniles treated with ethanediol, hydroxyethyl starch, and polyvinylpyrrolidone as cryoprotectants did not survive the cryopreservation procedure. Similar results were obtained with the pre-parasitic juveniles (PPJ) of Romanomermis yunanensis.
Plant parasitic nematodes associated with plantain (Musa spp., AAB-group) in southern Nigeria and their relative importance compared to other biotic constraints
Authors: Rotimi M. Omolara , De Waele Dirk , Speijer Paul R.
Published: January 2003

The predominant nematode species found on plantain in southern Nigeria was Helicotylenchus multicinctus which occurred at all 68 sites sampled. Hoplolaimus pararobustus, Pratylenchus coffeae and Radopholus similis were found at 64, 50 and 46% of the sites, respectively, while Meloidogyne spp. second stage juveniles were found at 68% of the sites. Other nematode species occurred at less than 5% of the sites and included Helicotylenchus dihystera, P. zeae, P. brachyurus, Rotylenchulus reniformis, Scutellonema and Criconemoides spp. H. multicinctus and P.coffeae occurred at high densities (on average about 10 500 and 3500 nematodes/100 g fresh root weight, respectively), compared to the other species. P.coffeae was more common in the west and mid-west of southern Nigeria, while R. similis was more common in the east. Factors, derived from a principal component analysis of observations of damage caused by nematodes, the banana weevil Cosmopolites sordidus and the fungus Mycosphaerella fijiensis, the cause of Black Sigatoka, were related to plant growth observations. The results suggest that P.coffeae followed by R. similis are the major biotic constraints of plantain production in southern Nigeria. Higher losses are anticipated by these plant parasitic nematodes than by either M. fijienis or C. sordidus.
Plant-parasitic nematodes in field crops in South Africa. 6. Soybean
Authors: McDonald Alexander , Fourie Hendrika , Loots Gideon
Published: January 2003

Twelve plant-parasitic nematode genera and 25 species were identified in soil and root samples collected from 17 localities in the soybean production areas of South Africa during the 1995/96 season. Predominant endoparasites found included Meloidogyne incognita, M. javanica, M. hapla, M. ethiopica, Pratylenchus zeae and P. brachyurus. Meloidogyne species occurred in 91% of all root samples, P. zeae in 87% and P. brachyurus in 33%. The occurrence of the three predominant endoparasites was not restricted to sandy soil, but they were also prevalent in soils with high clay contents. Other endoparasitic nematode species were Pratylenchus crenatus, P. teres, P. neglectus, P. thornei, Rotylenchulus parvus and Ditylenchus africanus. Nematodes found in soil included Helicotylenchus dihystera and Scutellonema brachyurus, which occurred in 78 and 71%, respectively, of all soil samples. Other nematodes found in soil samples were Helicotylenchus pseudorobustus, H. digonicus, H. microcephalus, Scutellonema truncatum, Rotylenchus unisexus, Mesocriconema sphaerocephalum, Paratrichodorus minor, Longidorus pisi, Xiphinema vanderlindei, X. elongatum and Tylenchorhynchus goffarti. Highest prominence values (PV) for Meloidogyne species were recorded on cultivars Prima, Bakgat, Tamboti, Hutcheson and Knap and the lowest on cultivars PAN812, SCS1, Nyala, Gazelle and A7119. Eight nematode genera and 19 species extracted during this study are reported for the first time in association with soybean in South Africa.
Presence of the cerambycid beetles Psacothea hilaris and Monochamus alternatus affecting the life cycle strategy of Bursaphelenchus xylophilus
Authors: Maehara Noritoshi , Futai Kazuyoshi
Published: January 2003

Although fourth-stage dispersal juveniles (JIV) of Bursaphelenchus xylophilus, the pinewood nematode (PWN), developed in the presence of both Monochamus alternatus and Psacothea hilaris, the numbers and the percentage of JIV were far higher in the presence of the former than of the latter. JIV first appeared 7 days after pupation of M. alternatus and the number increased from the day of beetle eclosion to the third day thereafter, then remained stable. We conclude that the presence of specific vectors affects both the life history of the PWN and the numbers of nematodes carried by vectors emerging from killed pine trees.
Invasion, development, growth and egg laying by Meloidogyne javanica in Brassicaceae crops
Authors: Kirkegaard John , McLeod Rod , Steel Christopher
Published: January 2003

Invasion, development and egg laying by Meloidogyne javanica in 11 Brassicaceae and four non-Brassicaceae crop species/subspecies was investigated. At 10 to15 and 15 to 20°C, fodder rape cv. Rangi was invaded less than the good hosts tomato cv. Grosse Lisse and field pea cv. Dun but more than the poor host oat cv. Cooba. With an inoculum of 50 second stage juveniles (J2), invasion of Rangi, and the intermediate host subterranean clover cv. Trikkala, were similarly invaded when inoculated with 50 and 100 J2, cv. Rangi was invaded less than tomato. The intermediate host subterranean clover cv. Trikkala and Rangi were similarly invaded when inoculated with 50 and 100 J2 but cv. Trikkala was less invaded with 200 J2. Oat cv. Cooba was always less invaded than the other hosts. Invasion of 3-week-old seedlings of cv. Rangi and 12 cultivars of seven other Brassicaceae crop species/subspecies were similar. Three weeks after inoculation, more M. javanica had developed to the mature female stage in tomato than in the eight Brassicaceae species/subspecies. Females growing in tomato and field pea were always larger than those in rape cv. Rangi. Females in Rangi were larger but those in oilseed radish cv. Adagio were smaller than in 11 other cultivars of seven Brassicaceae, except in plants grown in winter. Egg masses from four Brassicaceae species contained fewer eggs than egg masses from tomato at 6 weeks after inoculation, but at 7 and 8 weeks only those from fodder rape cv. Korina had consistently fewer than tomato. Results are discussed in relation to host status, glucosinolates and potential use of Brassicaceae for control of Meloidogyne.
Life history of Bursaphelenchus conicaudatus (Nematoda: Aphelenchoididae) in relation to the yellow-spotted longicorn beetle, Psacothea hilaris (Coleoptera: Cerambycidae)
Authors: Kanzaki Natsumi , Futai Kazuyoshi
Published: January 2003

The life history of the nematode Bursaphelenchus conicaudatus and its phoretic relationship to the yellow-spotted longicorn beetle, Psacothea hilaris, were studied, and are discussed by comparison with those of the pinewood nematode B. xylophilus, the pathogen of the pine wilt disease, and its vectors Monochamus species. The life history of B. conicaudatus was found to be very similar to that of B. xylophilus in dispersal pattern, vector selection and feeding preference, although the average number of B. conicaudatus carried by the yellow-spotted longicorn beetle, the proportion of beetles infested with the nematodes, and the nematode release pattern differed from those of B. xylophilus. These findings indicate a close relationship between the two species of Bursaphelenchus and the cerambycid beetles, as well as the adaptability of these two nematode species to the life cycles of their vectors.
Present status and future of nematode systematics
Authors: Coomans August
Published: January 2003

Since phylogenetic systematics became generally accepted and especially since informatics and molecular techniques for phylogenetic analysis were developed, systematics has undergone a conceptual and methodological revolution. Taxonomy, on the contrary, suffered a decline. Poor descriptions, too much routine work and low citation rates hampered it. As a result, the discipline became less attractive to young scientists. With only a small fraction of the biodiversity known, this situation will lead to serious problems in the future in all those fields of nematology depending on a correct identification of species. Phylogenetic analyses of nematodes have been mainly based on morphology, supplemented with developmental characters, but in recent years molecular methods have provided entirely new data sets. Phylogenetic estimates derived from independent data may provide new insights in character homologies through reciprocal illumination. Classifications of nematodes were often biased according to the expertise of the author and were only recently based on the principles of phylogenetic systematics. Recently, molecular and morphological data have been used to support a new overall classification with only (presumably) monophyletic taxa. In this classification plant, as well as animal, parasitic taxa are hierarchically downgraded in accordance with their phylogenetic history. Species occupy an important position in all aspects of biology, therefore the species concept matters. It determines, for example, the outcome of biodiversity assessments, distribution patterns, etc. However, several problems remain to be solved before a consensus will be reached about the choice of a concept. Future research in nematode systematics should comprise well-focused taxonomy based on a combination of classical and modern methods in a way that can raise the interest of young scientists as well as of funding agencies. It should be realised that, with the dwindling present taxonomic expertise, this is a very urgent matter.
Meloidogyne brasilensis n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitising tomato cv. Rossol in Brazil
Authors: Eisenback Jonathan , Charchar João
Published: January 2003

Meloidogyne brasilensis n. sp., Londrina and Brasilia populations, is described and illustrated from specimens from tomato cv. Rossol and pea cv. Mikado, respectively, in Brazil. Characteristically, the perineal pattern is elongated to ovoid with a flattened to very high, squarish dorsal arch with widely spaced, coarse striae. The lateral fields may have wing-like striae on one or both sides. The female stylet is 14 μm long with narrow and elongated knobs that are distinctly set-off from the shaft. The excretory pore is variable in location, but generally opens near the anterior portion of the median bulb about 50 μm from the head end. The male is 1.89 mm long and has a high head cap that slopes posteriorly. The labial disc is separated from the medial lips by a deep, rounded groove. The delicate stylet of the male is 23 μm long and has small, rounded knobs that are distinctly set-off from the shaft which has numerous small, rounded projections. Mean second-stage juvenile length is 434 μm. The juvenile head cap is highly elevated, the medial lips are crescent-shaped and unequal in size, and the head region is not annulated. The stylet is 11 μm long and has small, rounded, posteriorly sloping knobs. The tail is 53 μm long; it is marked with large, irregular annules and ends in a bluntly rounded tip. The hyaline tail terminus is short (13 μm). Reproduction occurred on NC95 tobacco, tomato, pea, and bean, whereas pepper, watermelon, peanut, cotton, corn, and soybean were not hosts.
Free-living nematodes from nature reserves in Costa Rica. 2. Mononchina
Authors: Bongers Tom , Zullini Aldo , Loof Pieter
Published: January 2003

In soil, moss and freshwater habitats of tropical forests in Costa Rica, 20 mononch species were found. Two are described as new species. Mononchus laminatus n. sp. (L = 1.5-1.9 mm, buccal capsule 29-31 × 11-14 μm, c′ = 3.6-4.9, similar to M. aquaticus but with a subventral lamina present in anterior part of buccal cavity, and amphid aperture posterior to the dorsal tooth) and Miconchus gomezi n. sp. (similar to M. digiturus, but with slender body, vulva cuticularised and with a reduced posterior genital branch). The known species are redescribed, the well-known ones briefly, the less known more extensively. Brazilian and Costa Rican specimens of Paracrassibucca paucidentata Lordello, 1970 were studied and a lectotype has been designated. The other species found are: Mononchus truncatus Bastian, 1865; M. aquaticus Coetzee, 1968; M. tunbridgensis Bastian, 1865; Coomansus parvus (de Man, 1880); Coomansus sp. (C. zschokkei-group); Prionchulus muscorum (Dujardin, 1845); P.punctatus Cobb, 1917; Cobbonchus coetzeeae Andrássy, 1970; Mylonchulus contractus Jairajpuri, 1970; M. hawaiiensis (Cassidy, 1931); M. obtusicaudatus (von Daday, 1899); M. parabrachyuris (Thorne, 1924); M. sigmaturus Cobb, 1917; Mulveyellus monhystera (Cobb, 1917); Iotonchus tenuidentatus (Kreis, 1924); I. trichurus Cobb, 1917 and Miconchus digiturus (Cobb, 1893).
A PCR primer set for determination of phylogenetic relationships of Bursaphelenchus species within the xylophilus group
Authors: Kanzaki Natsumi , Futai Kazuyoshi
Published: January 2003

The phylogenetic relationships of Bursaphelenchus conicaudatus with B. abruptus, B. fraudulentus, B. mucronatus and B. xylophilus species were analysed based on the DNA base sequences of 18S, 5.8S, ITS1 and ITS2 of rDNA and the partial code of mitochondrial cytochrome oxidase subunit I (COI) gene. The monophyly of B. abruptus and the other species in the xylophilus group was not supported, and B. abruptus could be excluded from the xylophilus group. The other species, i.e ., B. conicaudatus, B. fraudulentus, B. mucronatus and B. xylophilus were assumed to be monophyletic. The ancestor of these four species is assumed to have originated in the eastern part of the Eurasian continent as a free-living nematode inhabiting broad-leaved trees. First, B. conicaudatus branched from the ancestor in eastern Asia. Then B. fraudulentus and B. mucronatus separated from the ancestor. B. mucronatus changed its host from broad-leaved trees to conifers and spread throughout the coniferous forest over the Eurasian continent and North America. B. xylophilus might originate from a population of B. mucronatus remaining in North America after B. mucronatus had diversified.
Description of Trichodorus gilanensis n. sp. from a forest park in Iran and observations on Paratrichodorus tunisiensis (Siddiqi, 1963) Siddiqi, 1974 (Nematoda: Diphtherophorina)
Authors: Maafi Zahra , Decraemer Wilfrida
Published: January 2003

A new trichodorid species, Trichodorus gilanensis n. sp. is described from a forest park in northern Iran. The new species is characterised in the male by three ventromedian cervical papillae with the anterior two at the level of the onchiostyle region, the posterior-most ventromedian procloacal supplement (SP1) at the level of the retracted spicule head, spicules smooth and manubrium continuous with shaft, and in the female by large triangular vaginal sclerotised pieces close to one another in lateral view, a barrel-shaped vagina, a transverse slit-like vulva in ventral view and a slightly swollen tail region. Three other trichodorid species found, T. primitivus, Paratrichodorus porosus and P.tunisiensis represent new records for Iran.
Isolation of flavipin, a fungus compound antagonistic to plant-parasitic nematodes
Authors: Nitao James , Meyer Susan , Chitwood David , Schmidt Walter , Oliver James
Published: January 2003

An isolate of the fungus Chaetomium globosum produced culture broths that inhibited in vitro egg hatch and juvenile mobility of root-knot nematode (Meloidogyne incognita) and hatch of soybean cyst nematode (Heterodera glycines). Extraction and bioassay-directed fractionation of the culture broth filtrate determined that flavipin, a low molecular weight compound, was the fungus metabolite responsible for most of the nematode-antagonistic activity. Synthesis of flavipin permitted evaluation of the compound as a suppressor of nematode populations on plants in glasshouse studies. Muskmelon (Cucumis melo) plants in steamed and unsteamed soil were inoculated with root-knot nematodes and various concentrations of flavipin were applied to the soil. Contrary to expectations from the in vitro studies, the number of galls per g of roots increased with flavipin treatment at the 14-day harvest. No effect of flavipin on nematode populations was found at the 55-day harvest. In general, plant growth and nematode populations were greater in plants grown in steamed soil.
Use of ammonia-releasing compounds for control of the root-knot nematode Meloidogyne javanica
Authors: Oka Yuji , Pivonia Shimon
Published: January 2003

The nematicidal activities of ammonia-releasing and ammonium compounds were tested against the root-knot nematode Meloidogyne javanica in pot, microplot and field experiments. Among ten compounds tested, NH4OH, (NH4)2HPO4 and NH4HCO3 showed greatest nematicidal activity at concentrations of 300 mg N/kg of NH4 or NH2 in pots. NH4OH was found to be the most nematicidal of these compounds. Enclosure of pots containing NH4OH-treated soils in plastic bags reduced the concentration of NH4OH needed to kill the nematodes from 200 mg N/kg in open pots to only 75 mg N/kg. In a microplot experiment, treatment of nematode-infested soil with NH4OH at 70 mg N/kg reduced the root-galling index to 0. In one field experiment, the nematicidal efficacy of NH4OH on tomato plants at doses of 1000 and 2000 kg N/ha was equivalent to those of Telopic C35® or metham sodium in combination with cadusafos. In another field experiment, NH4OH at 500 and 1000 kg N/ha increased tomato yield and at 1000 kg N/ha reduced the galling index, compared with untreated controls. The results suggest that NH4OH may serve as a nematicide in alkaline sandy soils.
Importance of the O-antigen, core-region and lipid A of rhizobial lipopolysaccharides for the induction of systemic resistance in potato to Globodera pallida
Authors: Reitz Martina , Oger Peter , Farrand Stephen , Hallmann Johannes , Meyer Andreas , Sikora Richard , Niehaus Karsten
Published: January 2003

Lipopolysaccharides (LPS) of the rhizobacterium Rhizobium etli strain G12 are involved in the induction of systemic resistance in potato roots towards the potato cyst nematode Globodera pallida. In the present study, the wild type strain G12 and three LPS-mutant strains with truncated O-antigens all reduced nematode infection of potato plants to about 30% that of untreated controls. Therefore, the O-antigen of the bacterial LPS cannot be the sole inducer of the resistance mechanism. In further search of the mode of action, the isolated core-region and lipid A-fraction of the LPS of one O-antigen-mutant strain R. etli #4-153 were tested for elicitor activity. Using a split-root system, which provides spatial separation of the inducing agent from the parasite, it was shown that both the entire LPS and its core-region systemically reduced G. pallida infection to 45% that of the untreated control. In contrast, the lipid A-fraction was less effective; the 20% reduction in nematode infection was not different from the control nor from the LPS and core region treatments. It is concluded that the oligosaccharides of the core-region are the main trigger of systemic resistance in potato roots towards G. pallida infection.
Physiological ageing and behavioural plasticity of Heterorhabditis bacteriophora infective juveniles
Authors: Brown Ian , Cohen Nancy , Gaugler Randy
Published: January 2003

Heterorhabditis bacteriophora is a cruiser strategist that exhibits long distance ranging searches for insect hosts in soil. We characterised age-based variations in constituent behaviours and total lipid reserves of laboratory-aged H. bacteriophora infective juveniles. Individuals demonstrated extensive behavioural variability within the first 7 days, followed by accentuated ranging behaviour during the next 14 days and, finally, a decline in activity during the last 15 days. Frequency, bout duration and total time investment decreased almost 50% for forward crawling but almost doubled for backward crawling and curling. Both pausing and head waving frequency, a theoretical correlate of searching intensity, varied considerably without relation to age. Lipid content declined steadily, decreasing by 56% after 28 days. Behavioural changes became apparent after a 20% reduction in total lipid, and performance continued to decline with further lipid depletion. These findings emphasise the combined influences of environmental and physiological factors on behavioural plasticity in entomopathogenic nematodes.
The effect of osmotic stress on desiccation survival and water content of four nematode species
Authors: Wyss Urs , Fisher John , Charwat Suzanne
Published: January 2003

The effects of osmotic stress on water loss and subsequent desiccation survival of Anguina funesta second stage juveniles (J2), Rhabditis strongyloides (J2-J4), Aphelenchus avenae (J2-adult) and Heterorhabditis bacteriophora (J3) were investigated by incubating nematodes in sucrose gradients before exposure to 0% relative humidity (RH). Survival of A. funesta J2 was unaffected by osmotic stress and subsequent desiccation and juveniles seemed pre-adapted to both forms of dehydration. Heterorhabditis bacteriophora showed high tolerance to osmotic stress but all J3 were killed by exposure to 0% RH. Pre-exposure to osmotic stress improved desiccation tolerance in R. strongyloides and A. avenae but the stress levels that induced protective adaptations against desiccation were different for each species. Osmotically induced water loss was rapid in all four species and nematodes reached equilibrium after 4-12 h, their final water content being dictated by the osmotic pressure of the medium. A unique mechanism of osmotic adaptation occurred in R. strongyloides J2-J4 allowing juveniles to regain their initial hydration level.
Differential chemotactic responses of two plant-parasitic nematodes, Meloidogyne incognita and Rotylenchulus reniformis, to some inorganic ions
Authors: Quénéhervé Patrick , Le Saux Ronan
Published: January 2003

The orientation of juveniles of Meloidogyne incognita and Rotylenchulus reniformis was studied in salt gradients created in a linear agarose gel. Twelve combinations of calcium, potassium, sodium or ammonium cations and chloride, nitrate or sulphate anions were tested. The orientation of juveniles of M. incognita was induced by the constitutive cation of the salt, e.g., calcium salts had no effect while the other salts and especially ammonium salts and ammonium nitrate were strongly repellent. In contrast, the orientation of juveniles of R. reniformis was induced by the constitutive anion of the salt, e.g., chloride salts were found to be repellent while sulphate and nitrate salts were attractive. These results are discussed as possible novel control strategies for economically important plant parasitic nematodes. In other respects, these differences in chemical preferences may partly explain the observed geographical distribution of these nematode species according to the ionic content of the soils.
“German Jews,” “National Jews,” “Jewish Volk” or “Racial Jews”? The Constitution and Contestation of “Jewishness” in Newspapers of Nazi Germany, 1933–1938
Authors: Pegelow Thomas
Published: January 2003

After reading the “Jewish News Bulletin” (Jüdisches Nachrichtenblatt) in early 1939, the Romance language scholar Victor Klemperer wrote: “Until 1933 and for at least a good century before that, the German Jews were entirely German and nothing else … They were and remain (even if now they no longer wish to remain so) Germans …” Klemperer, a convert to Protestantism, but a “full Jew” by Nazi decree, continued, “It is part of the Lingua tertii imperii [LTI, language of the Third Reich] that the expression ‘Jewish people’ [Volk] appears repeatedly in the ‘Jewish News'…”
The Wheels of Justice Turn Slowly: The Pretrial Investigations of the Frankfurt Auschwitz Trial 1963–65
Authors: Wittmann Rebecca Elizabeth
Published: January 2003

The investigations into the crimes of the Auschwitz perpetrators by the Frankfurt public prosecutor's office began in 1958. The trial opened in 1963. Why did it take five years? In the 1960s, scholars such as Theodor Adorno, Alexander and Margarete Mitscherlich, and Hannah Arendt emphasized West German reticence, indifference, or even unwillingness to confront the Nazi past as explanations for the late start of investigations of Nazi criminals. They argued that the 1950s were dominated by a collective silence about Nazism and crimes against the Jews in Germany. According to them, politically, culturally, and also legally, the new West German state refused to acknowledge the Nazi past of anyone but the highest ranking Nazis, whose trial at Nuremberg marked theSchlussstrich(drawing the line) under the topic of National Socialism and its crimes against humanity. Recent historiography of postwar German trials has also pointed to lingering Nazi beliefs not only on the part of judges and lawyers but in the minds of the public as well.
The Question of Validity in Qualitative Research
Authors: Giorgi Amedeo
Published: January 2003

It seems that many qualitative researchers have still not contextualized the role of validity in qualitative analysis.This article enumerates three factors that must be taken into account: (1) The philosophy of science within which one works, (2) the discipline to which one belongs, and (3) the subfield of specialization that one pursues. Most researchers have encountered the question of validity within the context of empirical science, but validity does not have the same role within a phenomenological philosophy of science. Within the discipline of psychology, certain subfields ignore the validity issue for good reasons (e.g., experimentation in psychophysics) and other subfields specialize in developing strategies for validity. This article analyzes the reasons that the specialty of "test construction" focuses so strongly on validity issues and concludes that phenomenological qualitative research is not at all similar to the situation one finds in test construction. Rather, phenomenological qualitative research is closer to experimental situations and so the validity issue is not as pressing as is often supposed. The article ends with two different Husserlian perspectives on a theory of knowledge.
Making Phenomenology Accessible to a Wider Audience
Authors: Halling Steen
Published: January 2003

Phenomenological research is of great value to clinicians, policy makers, and ordinary persons because of its distinctive emphasis on making human behavior and experience intelligible with reference to the point of view of the actor. Unfortunately, the phenomenological tradition is not readily accessible to readers who are unfamiliar with it. This article discusses specific ways that researchers within this tradition can reach more of the readers who might benefit from their findings without compromising the integrity of their scholarship.
An Experience of International Terrorism: Reflections on the Meanings of September 11th
Authors: Wertz Frederick
Published: January 2003

This lecture, delivered in the "Transcending Tragedy" series at Fordham University in New York City, in February, 2002, presents reflections on the recent experience of international terrorism. A temporal unfolding of meanings experienced during and after the September 11th attacks is described beginning with that fateful morning and concluding with the changed post-9/11 world. This analysis reveals the fragility and plasticity of the social dimension of individual experience as well as our responsibility to create a global order of peace in the face of inimical difference.
Psychotherapy and Existential Therapy
Authors: Colaizzi Paul
Published: January 2003

The aim of this essay is to provide an overview of how Existential Therapy is fundamentally different from every kind of psychotherapy, including existential psychotherapy. Existential Therapy is no kind of psychotherapy. Confusing the practicing of the two can harm people and thoughts. Existential Therapy is therapy for existence, whereas psychotherapy is therapy for life, a remedy for the problems of living. The adequate distinction between life and existence is an issue that shamefully has gone unaddressed in existential philosophy, existential psychology and research, and existential psychotherapy. This essay describes the main differences between life and existence, and then takes a look at what is healthy for existence versus what is healthy for life. What is found to be most unhealthy for existence is metacarnalizing, recoiling from carnal limits. Metacarnalizing is a primary existential reversal. Existential therapy unreverses existential reversals. Existential therapy unreverses metacarnalizing. Existential therapy essentially de-metacarnalizes. The issue of metacarnalizing and de-metacarnalizing is absolutely alien to all forms of psychotherapy for life. The essay is followed by an appendix, "An Existential View of Physics," which mainly describes the metacarnalizing basis of physics throughout its history.
The Study of Religious Belief after Donald Davidson
Authors: Schilbrack Kevin
Published: January 2003

Scholars in religious studies are increasingly drawing important insights from Davidson's philosophy of language. Unfortunately, the most prominent of Davidson's interpreters in religious studies have been Rortian neopragmatists who, I argue, have read into Davidson views which are not his own. This essay seeks to disentangle Davidson's stance from its neopragmatist interpretations. The goal is to understand his stance in order to see how one might approach the study of religious beliefs, and in particular religious metaphysical beliefs, from a Davidsonian perspective.
"BUT TOUCH THE LAW AND THE SECT WILL SPLIT:" LEGAL DISPUTE AS THE CAUSE OF SECTARIAN SCHISM
Authors: Baumgarten Albert
Published: January 2003

My intention in this paper is to take issue with a view widely held among scholars in the field, an opinion I shared in the past but that I have also questioned and ultimately come to reject. To set the stage for accomplishing this goal let me begin with a definition of a historian offered by my late teacher, Professor Elias Bickerman. He called a historian a "digger in texts." The comparison to an archeologist, who digs in the ground, is enlightening. Every layer of a site contributes something to the complete history of its occupation, and that total picture can only be drawn on the basis of information from every layer, in which each layer teaches us something about any and all of the other layers. Nevertheless, an archeologist digging at a particular site is usually most interested in the remains from one particular stratum. For that archeologist, these remains are of the greatest importance.
Efectos de la clasificación del comportamiento del modelo simbólico televisado sobre la agresividad infantil
Authors: León José María , Cantero Francisco Javier , Gómez Tomás
Published: January 2003

Se formuló la siguiente hipótesis: el efecto de la exposición a modelos simbólicos televisados sobre la agresividad infantil depende de la clasificación que hacen los niños, en términos de permisibilidad o prohibición, de las conductas agresivas del modelo. Se utilizó un diseño de tres grupos al azar. La variable independiente fue la exposición a un modelo con tres niveles de comportamiento agresivo: permisible, prohibido o neutral. Cada grupo constó de ocho niños con 8 y 9 años de edad, de los cuales 3 eran varones y 5 mujeres, que después de visionar el modelo agresivo fueron observados en una situación de juego libre, durante la cual se registró la frecuencia con la que los niños emitieron los comportamientos agresivos del modelo. Los resultados confirmaron la hipóteis formulada; el modelo agresivo permisible fue más imitado y generó más agresividad que el resto de los modelos.
Arousal psicofisiológico y autoinformado: diferencias entre sujetos con patrón de conducta Tipo A y Tipo B
Authors: Dorado Miguel Angel , Fernández Inmaculada
Published: January 2003

El propósito del presente estudio fue analizar las diferencias en los niveles de arousal entre sujetos Tipo A y Tipo B. Las medidas de arousal consistieron en un cuestionario autoinformado (Escala de Predisposición al Arousal de Coren) y dos medidas psicofisiológicas (tasa cardíaca y nivel de conductancia de la piel) tomadas en estado de reposo. El análisis psicométrico de la Escala de Predisposición al Arousal reveló: una aceptable fiabilidad, un adecuado poder discriminativo de los items y la capacidad de clasificar correctement a los sujetos Tipo A y Tipo B. Los resultados indicaron que los sujetos Tipo A mostraron una mayor predisposición a un mayor estado de activación y unos mayores niveles en la actividad electrodermal.
Situaciones sociales: su poder de transformación
Authors: Zimbardo Philip
Published: January 2003

A través de investigaciones experimentales y análisis socio-históricos, en los cuales hombres y mujeres normales y corrientes son inducidos a comportarse de modo perverso, se muestra una perspectiva situacional sobre las causas de la conducta antisocial de los individuos y sobre la violencia sancionada por las naciones. Esta aproximación socio-psicológica se contrapone al enfoque disposicional más tradicional que se centra en las causas internas, o en la personalidad, para explicar la conducta antisocial. Los resultados de este trabajo confirman el principio lewiniano que postula que es posible investigar, dentro del “mundo real”, fenómenos sociales vitales mediante procedimientos experimentales. El trabajo se centra principalmente en mis propios estudios, tanto en aquellos realizados en el laboratorio como en los de campo, sobre la desindividuación, la agresión y el vandalismo, y el experimento de la “Prisión de Stanford”, junto con un proceso de análisis de los estudios de obediencia de Milgram y el análisis de “Desvinculación Moral” de Bandura. Este corpus de investigación demuestra el poder que tienen las situaciones sociales para modificar las representaciones mentales y la conducta de los individuos, grupos y naciones. Como contexto de referencia inmediato he escogido la epidemia de violencia en los Estados Unidos.
Factores predictores de la autoestima con los iguales y de la intimidad relacional en la adolescencia
Authors: Fuertes Antonio , Carpintero Eugenio , Martínez José Luis , Soriano Sonia , Hernández Amparo
Published: January 2003

El objetivo de la presente investigación es analizar la asociación existente entre diferentes variables personales (instrumentalidad, expresividad, autoconciencia privada, autoestima familiar, ansiedad social y habilidades de comunicación) y dos importantes aspectos de las relaciones de amistad en los adolescentes: la autoestima en relación con los iguales y la intimidad experimentada con el mejor amigo/a. La muestra utilizadapara el estudio ha sido de 610 estudiantes salmantinos (284 chicos y 326 chicas), comprendidos entre los 14 y los 19 años, quienes completaron una serie de autoinformes con objeto de evaluar las diferentes variables predictoras y criterios. Los análisis realizados muestran que, tanto en los chicos como en la chicas, las habilidades de comunicación es la variable que por sí sóla predice un mayor porcentaje de la varianza en la autoestima con los iguales y en la intimidad con el mejor amigo/a. Adicionalmente hay que destacar la importante relación de la instrumentalidad con la autoestima con los iguales, y de la expresividad y la autoestima familiar con la intimidad con el mejor amigo/a.
Sobrevaloración reactiva de las propuestas no ofrecidas en el curso de una negociación
Authors: Garrido Eugenio , Herrero Carmen , Tabernero Carmen
Published: January 2003

En este estudio se propone una interpretación alternativa, teórica y metodológica, a la devaluación reactiva de L. Ross y colaboradores. Esta reintepretación se hace a la luz de la teoría de la reactanciapsicológica de Brehm, a la que se acogen los autores californianos. Tomando como línea base la valoración realizada por un grupo control, a) no se confirma la devaluación reactiva de aquello que no se ofrece en el momento de la negociación; b) se prueba la sobrevaloración reactiva del bien no ofrecido cuando éste es escaso y específico; c) finalmente, se rehabilitan el GRIT de Osgood y los principios de la reciprocidad y la escasez de Cialdini como estrategias de negociación y de persuasión.
Valores personales individualistas y colectivistas y su relación con la autoestima colectiva
Authors: Ros María , Gómez Angel
Published: January 2003

El Individualismoy el Colectivismo como orientaciones generales de valores en los que prima el interés por la persona o el interés por la colectividad ha sido objeto de distintas contribuciones teóricas. Algunas de las más recientes, Triandis y col. (1988), Schwartz (1992) Ros y Schwartz (1995, 1996) divergen en la consideración de la unidimensionalidad o bidimensionalidad de estas orientaciones valorativas. Es más también se encuentran divergencias de matiz entre Hinkle y Brown (1992) y Triandis (1992) en la relación entre identificación endogrupal y la orientación individualista o colectivista de valores.

Dos grupos, uno de estudiantes jugadores de baloncesto y otro sólo estudiantes, ambos de distintos institutos y de la misma edad y nivel socio-cultural contestaron la escala de los tres factores de Triandis (1988) así como el SVS, cuestionario de valores personales de Schwartz (1987) y la escala de Autoestima Colectiva de Luthanen y Croker (1992). Nuestra investigación muestra que los valores individualistas y colectivistas siguen la orientación bidimensional propuesta por Schwartz y que la Autoestima colectiva, a través del factor de identificación grupal, está asociada a un perfil de valores tanto individualistas, como colectivistas y de orientación mixta.
Crítica al enfoque metodológico tradicional para el estudio de la polarización grupal: acercamiento desde el análisis categórico de datos
Authors: Meliá José Luis , Rodrigo Ma Florencia , Sesé Alberto , Sospedra Ma José
Published: January 2003

El presente artículo revisa el paradigma experimental de contraste de la polarización grupal desde el punto de vista del análisis estadístico, discute e ilustra las serias deficiencias metodológicas del análisis estadístico utilizado comúnmente en la literatura para contrastar el fenómeno de la polarización grupal (pruebas t y ANOVAS) y propone una vía alternativa de análisis para establecer la prevalencia del fenómeno utilizando análisis para datos categóricos. A la luz de la crítica efectuada la evidencia sobre polarización grupal necesita ser reanalizada desde el nuevo enfoque de análisis propuesto.
La comunicación mural: análisis de contenido de graffiti universitarios
Authors: Goikoetxea Edurne
Published: January 2003

El presente artículo examina graffiti universitarios recogidos en aseos de varones y mujeres de una Universidaden el País Vasco. Los graffiti fueron clasificados por un juez independienteen un total de 18 categorías de contenidos. El análisis de contenido reveló que la temática política y la sexual fueron las más frecuentes. Se encontró que los varones produjeron más graffiti que las mujeres, con el 79,1% del total. Los graffiti de aseos masculinos mostraron un rango de temáticas más amplio que los graffiti de aseos femeninos, así como diferencias en la frecuencia con que se trataron los diversos contenidos. Contenidos tales como política, insultopolítico y sexualidad fueron los más frecuentes en aseos masculinos, mientras que temáticas tales como sexualidad, nombres e insulto general lo fueron en los aseos femeninos. Estos resultados se comparan con otros de estudios precedentes. La alta frecuencia de la temática política se discute en relación con el contexto y el momento social en que se recogieron los graffiti del presente estudio.
Representaciones sociales o la orientación hermenéutica en la Psicología
Authors: Rojas José Oriol
Published: January 2003

En este trabajo se va a intentar determinar la utilidad de las representaciones sociales para la Psicología. Para ello, en primer lugar se analizan las metodologías más utilizadas para su estudio, destacando la técnica del análisis del discurso, técnica que se aplica a un texto deJodelet en el que se define la entidad de las representaciones sociales.

De este estudio se concluye que la noción de representación social que se maneja en la comunidad científica es difusa y poco operativa, por lo que, en primer lugar, se propone una definición alternativa, y en segundo lugar se procede a dividirla en tres entidades: construcciones representacionales, construcciones personales y construcciones circunstanciales. Señalando finalmente su constitución semiótica que incorpora tanto al lenguaje como a las prácticas sociales.
Discursos y prácticas socio-urbanas en Río de Janeiro
Authors: de Souza Filho Edson Alves
Published: January 2003

A partir del Análisis Proposicional del Discurso (Ghiglioni y Blanchet, 1991), de dos grupos de habitantes de Río de Janeiro situados cultural y socio-economicamente, hemos intentado delimitar condiciones psicosociales para la implicación en acciones sociales de cambio urbano. La primera condición psicosocial observada es la producción de una representación social específica y particular sobre el objeto urbano a cambiar; la segunda, la identificación con el grupo de pertenencia urbana; y, finalmente, la tercera, la producción de una representación del grupo como si fuese un sujeto activo y valorizado positivamente. La observación de dos grupos en Rio de Janeiro nos ha aportado una validación inicial de estas predicciones.
Influencia de las expectativas estereotípicas en la espontaneidad del proceso inferencial
Authors: Betancort Verónica
Published: January 2003

Esta investigación analiza la influencia de la información congruente vs. incongruente con las expectativas estereotípicas en el grado de espontaneidad del proceso inferencial. Con este objetivo se realizó un experimento en el que participaron 31 sujetos distribuidos en varios grupos según el tipo de información asociada a la categoría (congruente vs. incongruente), el tipo de rasgo (fáciles para imaginar conductas y necesitan pocas conductas para ser confirmados o desmentidos vs. fáciles y necesitan muchas conductas vs. difíciles y necesitan pocas conductas vs. difíciles y necesitan muchas conductas), y la pista que se proporcionaba en la prueba de recuerdo (relacionada con el actor, con la conducta o sin pista). La variable dependientefue el recuerdo total de la frase o de partes de la misma. Los resultados muestran que no se produce una inferencia espontánea de rasgos en todos los casos. Concretamente, se obtienen más inferencias espontáneas con informaciones congruentes con el estereotipo que con informaciones incongruentes. Además, la inferencia espontánea solo se da cuando los rasgos son fáciles de imaginar necesiten muchas o pocas conductas para confirmarse o desmentirse. Esto lleva a concluir que los dos factores estudiados inciden en la espontaneidaddelproceso de inferencia de rasgos.