bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of CLOCK gene polymorphism on circadian mood fluctuation and illness recurrence in bipolar depression
Authors: Benedetti Francesco , Serretti Alessandro , Colombo Cristina , Barbini Barbara , Lorenzi Cristina , Campori Euridice , Smeraldi Enrico
Published: October 2003

Recent studies showed that a polymorphism (T to C nucleotide substitution) in the 3′ flanking region of the human CLOCK gene is associated with diurnal preferences of human healthy subjects, with higher “eveningness” in subjects carrying at least one copy of the C allele. We investigated the possible role of CLOCK gene polymorphism in the regulation of diurnal mood fluctuations during a major depressive episode. Sample (n = 101) was collected, in the context of previously reported trials, among patients affected by bipolar disorder type I, depressive episode without psychotic features, free of psychotropic medications. Perceived mood levels were assessed three times a day with self‐administered visual analogue scales. Genotype groups showed no significant difference in diurnal mood fluctuations. When stratifying the sample by including only patients with an adequate period of observation (duration of illness higher than 5 years, n = 69), we post‐hoc observed a significantly higher recurrence rate in homozygotes for the C variant, which was almost double than that of the other genotype groups. This preliminary observation leads to hypothesize a role for the CLOCK gene polymorphism in the regulation of long‐term illness recurrence in bipolar disorder. Given the post‐hoc nature of the finding, replication in independent samples is necessary to confirm it. © 2003 Wiley‐Liss, Inc.
Comparison of polymorphisms in the α7 nicotinic receptor gene and its partial duplication in schizophrenic and control subjects
Authors: Gault Judith , Hopkins Janet , Berger Ralph , Drebing Carla , Logel Judith , Walton Catherine , Short Margaret , Vianzon Ruby , Olincy Ann , Ross Randal G. , Adler Lawrence E. , Freedman Robert , Leonard Sherry
Published: October 2003

The hypothesis that the 15q13‐15 region of chromosome 15 contains a gene that contributes to the etiology of schizophrenia is supported by multiple genetic linkage studies. The α7 neuronal nicotinic acetylcholine receptor (CHRNA7) gene was selected as the best candidate gene in this region for molecular investigation, based on these linkage findings and biological evidence in both human and rodent models. CHRNA7 receptors are decreased in expression in postmortem brain of schizophrenic subjects. A dinucleotide marker, D15S1360, in intron two of the CHRNA7 gene is genetically linked to an auditory gating deficit found in schizophrenics and half of the first‐degree relatives of patients. Single strand conformation polymorphism (SSCP) and sequence analyses of DNA from schizophrenic and control individuals identified 33 variants in the coding region and intron/exon borders of the CHRNA7 gene and its partial duplication, dupCHRNA7; common polymorphisms were mapped. Twenty‐one variants were found in the exons, but non‐synonymous changes were rare. Although the expression of CHRNA7 is decreased in schizophrenia, the general structure of the remaining receptors is likely to be normal. © 2003 Wiley‐Liss, Inc.
Genome‐wide linkage survey for genetic loci that influence the development of depressive disorders in families with recurrent, early‐onset, major depression
Authors: Zubenko George S. , Maher Brion , Hughes Hugh B. , Zubenko Wendy N. , Stiffler J. Scott , Kaplan Barry B. , Marazita Mary L.
Published: October 2003

In this report, we describe the results of the first genome‐wide linkage survey for genetic loci that influence the development of unipolar Mood Disorders in 81 families identified by individuals with Recurrent, Early‐Onset, Major Depressive Disorder (RE‐MDD). Model‐free linkage analysis was performed using genotypes for 392 highly informative polymorphisms with an average spacing of 9 cM. The highest maximum LOD score observed, 8.19 (genome‐wide adjusted P ≪ 0.0001), occurred for Recurrent Major Depressive Disorder (R‐MDD) at D2S2321 (205 cM), located 121 kb proximal to CREB1. Nineteen chromosomal regions contained linkage peaks that reached genome‐wide statistical significance (genome‐wide adjusted P < 0.05) and ten of these were “highly significant” (adjusted P < 0.001). Six of the 19 linkage peaks were revealed only when the analysis included covariates to control for the effects of sex and linkage to CREB1. Sex‐specific susceptibility loci were common and preferentially affected the vulnerability of women to developing unipolar Mood Disorders. Five loci revealed evidence of interaction with the CREB1 locus in determining susceptibility (epistasis). A systematic candidate gene analysis is presented and potential overlaps of the linkage regions for unipolar Mood Disorders with those reported for other psychiatric disorders are discussed. The findings suggest that genes whose products participate in cellular signaling pathways that converge on CREB, as well as the target genes whose expression they regulate, may also harbor alleles that affect the development of Mood Disorders and related conditions. © 2003 Wiley‐Liss, Inc.
Primates as pets in Mexico City: An assessment of the species involved, source of origin, and general aspects of treatment
Authors: Duarte‐Quiroga Alejandra , Estrada Alejandro
Published: October 2003

The large human populations in cities are an important source of demand for wildlife pets, including primates, and not much is known about the primate species involved in terms of their general origin, the length of time they are kept as pets, and some of the maintenance problems encountered with their use as pets. We report the results of a survey conducted in Mexico City among primate pet owners, which was aimed at providing some of the above information. We used an ethnographic approach, and pet owners were treated as informants to gain their trust so that we could enter their homes and learn about the life of their primate pets. We surveyed 179 owners of primate pets, which included 12 primate species. Of these, three were native species (Ateles geoffroyi,Alouatta pigra, andA. palliata). The rest were other neotropical primate species not native to Mexico, and some paleotropical species. Spider monkeys and two species of howler monkeys native to Mexico accounted for 67% and 15%, respectively, of the primate cases investigated. The most expensive primate pets were those imported from abroad, while the least expensive were the Mexican species. About 45% of the native primate pets were obtained by their owners in a large market in Mexico City, and the rest were obtained in southern Mexico. Although they can provide companionship for children and adults, primate pets are subject to a number of hazards, some of which put their lives at risk. The demand by city dwellers for primate pets, along with habitat destruction and fragmentation, exerts a significant pressure on wild populations in southern Mexico. Am. J. Primatol. 61:53–60, 2003. © 2003 Wiley‐Liss, Inc.
Hormonal changes during the mating and conception seasons of wild northern muriquis (Brachyteles arachnoides hypoxanthus)
Authors: Strier Karen B. , Lynch Jessica W. , Ziegler Toni E.
Published: October 2003

We investigated hormonal and behavioral changes in wild male and female northern muriquis (Brachyteles arachnoides hypoxanthus) at the Estação Biológica de Caratinga, Minas Gerais, Brazil, during a 6‐mo period that encompassed the onset of the 1998–1999 mating and conception seasons. Individual females resumed mating with the resumption of ovarian cycling, which was not synchronized among them or related to their cortisol levels. Females experienced two to seven cycles prior to conceiving, and the first conception occurred 2 mo after the onset of the group's mating season. There were no differences in female cortisol levels across their premating, mating, and conception conditions. Cortisol levels were significantly higher in females than in males prior to the conception season, consistent with the prediction that energy reserves may be associated with breeding readiness in females, but not males, in this species. The sustained elevation in male cortisol occurred after the peak in their sexual activity, which resulted in the first conception of the year. Male cortisol levels were positively correlated between years that were similar in rainfall, but differed in the timing of sexual and reproductive events. The timing of cortisol elevations in males appears to be generally regulated by environmental cues, but is responsive to fine‐tuning by social and behavioral cues related to the unpredictable timing of reproductive opportunities within their extended mating season. Am. J. Primatol. 61:85–99, 2003. © 2003 Wiley‐Liss, Inc.
Proximity patterns of female western lowland gorillas (Gorilla gorilla gorilla) during the six months after parturition
Authors: Stoinski T.S. , Hoff M.P. , Maple T.L.
Published: October 2003

Studies of wild mountain gorillas have demonstrated strong preferences among new mothers for the silverback. Protection against infanticide has been theorized to be the primary cause for this attraction. We examined social partner preferences in captive western lowland mothers during the 6 mo after parturition and found that juveniles and females were the primary members of the new mothers' social network. Mothers spent significantly more time in close proximity with both of these subgroups than with the silverback. Proximity patterns changed over time: new mothers spent more time near females in the month after parturition than in the month prior to parturition, and spatial proximity increased again in months 2–6 postparturition. These findings differ from those reported for wild mountain gorillas, which may reflect the lack of infanticide risk in captivity. Given current hypotheses that infanticide may be a limited in western lowland gorillas, the social partner preferences observed here may be indicative of patterns in wild populations. Am. J. Primatol. 61:61–72, 2003. © 2003 Wiley‐Liss, Inc.
Personality influences tetanus‐specific antibody response in adult male rhesus macaques after removal from natal group and housing relocation
Authors: Maninger Nicole , Capitanio John P. , Mendoza Sally P. , Mason William A.
Published: October 2003

Previous research has suggested that personality is related to immune function in macaques. Using a prospective design, we examined whether variation in the personality dimension “Sociability” in adult male rhesus macaques (Macaca mulatta) was related to the in vivo secondary antibody response to a tetanus toxoid booster immunization following removal from natal groups and relocation to individual housing. We also explored whether the timing of the immunization following relocation had an impact on the immune response. Blood was sampled at the time of booster immunization, at 14 and 28 days post‐immunization, and approximately 9 months post‐immunization. Plasma was assayed for tetanus‐specific IgG by enzyme‐linked immunoassay (ELISA). There was no difference between High‐ and Low‐Sociable animals in antibody levels at the time of the booster immunization. Multivariate analysis of variance (MANOVA) revealed that High‐Sociable animals had a significantly higher antibody response following relocation and immunization compared to Low‐Sociable animals. There was no effect of timing of the immunization on the immune response. The results confirm that personality factors can affect animals' immune responses, and that the dimension Sociability may be influential in a male's response to social separation and relocation. Am. J. Primatol. 61:73–83, 2003. © 2003 Wiley‐Liss, Inc.
Membership characteristics of the American society of primatologists through 2002
Authors: Schapiro Steven J.
Published: October 2003

Approximately once a decade, the Treasurer of the American Society of Primatologists (ASP) publishes a report on the current membership characteristics of the society. Each year, when members join the ASP they answer a series of questions designed to evaluate the composition of the society and the interests of its members. In 2002 the society had 691 members (443 full members, 222 student members, and 26 retired members). This represents only a 3.1% increase in overall membership during the past decade, and a decrease of 10.8% from 2001. Over the years, the proportion of student (32.1%) and retired (3.8%) members has grown considerably, while the proportion of full members (64.1%) has decreased correspondingly. Of 691 members, 59 were source‐country primatologists who received complimentary (full or student) memberships. Women now comprise 57.7% of the membership, an increase of 5.9% over the last decade. Recent changes in the assessment and collection of annual dues have resulted in three important membership changes. First, 8.5% of current ASP members are source‐country primatologists who receive complimentary memberships in the ASP and complimentary subscriptions to the American Journal of Primatology (AJP). Second, mandatory subscription to AJP for full and student members in 2000 resulted in an immediate 8.7% decrease in membership, which appears to be continuing. Third, in 2002 approximately 50% of the members opted to pay their ASP dues with a credit card and/or via the Internet. It is hoped that the current decline in membership numbers represents a temporary trend, and that this loss will be reversed by 2004. Am. J. Primatol. 61:45–52, 2003. © 2003 Wiley‐Liss, Inc.
Die Ethylenpolymerisation mit Ziegler‐Katalysatoren 50 Jahre nach der Entdeckung
Authors: Böhm Ludwig L.
Published: October 2003

Vor einem halben Jahrhundert entdeckten Karl Ziegler und Mitarbeiter die Synthese von Polyethylenen bei niedrigen Drücken und mäßig hohen Temperaturen mit Übergangsmetallkatalysatoren der 4. Nebengruppe und aluminiumorganischen Verbindungen als Cokatalysatoren. Die 50 Jahre bis heute sind eine Innovationsgeschichte in Wissenschaft und Industrie, der Entwicklung hochaktiver Katalysatoren und eines großtechnischen Prozesses auf der Grundlage eines detaillierten Verständnisses aller relevanter chemischer und physikalischer Vorgänge auf allen Größenskalen. Katalysatoren, Verfahren und Produkte werden auch heute ständig weiterentwickelt, Zeichen dafür, dass das Potenzial dieses Polymerisationsprozesses noch nicht vollständig ausgeschöpft ist. Ziel dieser Forschungs‐ und Entwicklungsarbeiten ist, noch bessere Eigenschaftskombinationen der Produkte bei noch geringeren Herstellkosten zu erreichen und andere Werkstoffe wie Glas, Papier, Stahl, Beton in bestimmten Anwendungen zu ersetzen, da Polyethylene im Hinblick auf Ressourcenschonung die besseren Problemlösungen erbringen.
Cover Picture: The Ethylene Polymerization with Ziegler Catalysts: Fifty Years after the Discovery (Angew. Chem. Int. Ed. 41/2003)
Authors: Böhm Ludwig L.
Published: October 2003

Fifty years ago Karl Ziegler and co‐workers discovered the now‐famous process for the catalytic production of polyethylene at moderate temperatures and pressures. The cover of the patent gives November 18, 1953 as the priority date. Today, 50 years on, as a result of highly active catalysts and a detailed understanding of the system on all scales, it is still an extremely viable process. In his Review on page 5010 ff. L. L. Böhm describes the current industrial process based on Ziegler catalysts.
4‐(5‐Chloro‐2(3H)‐benzoxazolon‐3‐yl) Butanoic Acid Derivatives: Synthesis, Antinociceptive and Anti‐inflammatory Properties
Authors: Gulcan Hayrettin Ozan , Kupeli Esra , Unlu Serdar , Yesilada Erdem , Sahin Mustafa Fethi
Published: October 2003

In this study, 4‐(5‐chloro‐2(3H)‐benzoxazolone‐3‐yl)butanoic acid and its ethyl ester as well as its ten new amide derivatives have been synthesized. Their structures have been elucidated by IR, 1H‐NMR spectra and elemental analysis. The compounds were screened for antinociceptive and anti‐inflammatory activities. The highest antinociceptive and anti‐inflammatory activities were exhibited by Compound 11 which has carboxylic acid structure. A various decrease in antinociceptive and anti‐inflammatory activity was observed by amidation of the carboxylic acid moiety of this compound.
Invesgations on the Influence of Halide Substituents on the Estrogen Receptor Interaction of 2, 4, 5‐Tris(4‐hydroxyphenyl)imidazoles
Authors: Gust Ronald , Busch Sandra , Keilitz Roland , Schmidt Kathrin , von Rauch Moriz
Published: October 2003

Previously, we reported on the synthesis and estrogen receptor (ER) interaction of imidazoles, which had to be 1‐alkyl‐4, 5‐bis(2‐halo‐4‐hydroxyphenyl) substituted for a high relative binding affinity (RBA >1 %). This led to the assumption that a shielding of the polar heterocyclic system is a prerequisite for ER binding. In continuation of this study we synthesized 2, 4, 5‐tris(4‐hydroxyphenyl)imidazoles with Cl‐or F‐atoms in the ortho‐positions of the aromatic rings and evaluated whether they mediate sufficient hydrophobicity for ER interaction. 2‐(2, 6‐Dichloro‐3/4‐hydroxyphenyl)‐4, 5‐bis(2‐halo‐4‐hydroxyphenyl)imidazoles were synthesized by reaction of the respective methoxy‐substituted benzil with either the 2, 6‐dichloro‐4‐methoxy‐or the 2, 6‐dichloro‐3‐methoxybenzaldehyde in ammonium acetate solution. The required ether cleavage was performed subsequently with BBr3. In the competition experiment with [3H]estradiol the imidazoles with the a C2‐standing (2, 6‐dichloro‐4‐hydroxyphenyl) ring showed an RBA >0.02 %, but did not activate the luciferase gene in estrogen receptor positive MCF‐7‐2a breast cancer cells stably transfected with the plasmid EREwtcluc. In the test for antagonistic potency only the 2‐(2, 6‐dichloro‐4‐hydroxyphenyl)‐4, 5‐bis(4‐hydroxyphenyl)imidazole 3 antagonized the effects of 1 nM estradiol slightly. From these data, it can be concluded that a C2‐standing 2, 6‐dichloro‐4‐hydroxyphenyl ring is not appropriate to optimize the ER interaction of 4, 5‐(4‐hydroxyphenyl)imidazoles.
Synthesis, in vitro and in vivo Evaluation of a Delivery System for Targeting Anticancer Drugs to the Brain
Authors: El‐Sherbeny Magda A. , Al‐Salem Huda S. , Sultan Maha A. , Radwan Mahasen A. , Farag Hassan A. , El‐Subbagh Hussein I.
Published: October 2003

A 1, 4‐dihydropyridine ⇌ pyridinium salt type redox system is described as a general and flexible method for site‐specific and sustained delivery of drugs to the brain. This concept was used in the present investigation as a model to deliver an alkylating antitumor agent into the brain. A bis‐(chloroethyl)amine drug was hooked to 1, 4‐dihydropyridine chemical delivery system (CDS) through an amide linkage. Five newtarget compounds (23—27) of the 1, 4‐dihydropyridine CDS type were synthesized through the reduction of five new pyridinium quaternary intermediates (18—22). The synthesized 1, 4‐dihydropyridines were subjected to various chemical and biological investigations to evaluate their ability to cross the blood‐brain barrier (BBB), and to be oxidized biologically into their corresponding quaternary compounds. The in vitro oxidation studies showed that 1‐benzyl‐3‐{N‐[2‐bis(2‐chloroethyl)aminoethyl]‐carbamoyl}‐1, 4‐dihydropyridine (23) and 1‐(4‐nitrobenzyl)‐3‐{N‐[2‐bis(2‐chloroethyl)aminoethyl ]carbamoyl}‐1, 4‐dihydropyridine (27) could be oxidized into their corresponding quaternary compounds 18 and 22 respectively, at an adequate rate, which ensure the release of the carried anticancer drug. The in vivo studies showed that compound 23 was able to cross the BBB at detectable concentrations. On the other hand, the in vitro alkylation activity studies revealed that 1‐(4‐nitrobenzyl)‐3‐{N‐[2‐bis(2‐chloroethyl)aminoethyl]carbamoyl}pyridinium bromide (22) is an alkylating agent with activity comparable to the known drug chlorambucil.
Dopamine Receptor Ligands. Part VII [1]: Novel 3‐Substituted 5‐Phenyl‐1, 2, 3, 4, 5, 6‐hexahydro‐azepino‐[4, 5‐b]indoles as Ligands for the Dopamine Receptors
Authors: Decker Michael , Lehmann Jochen
Published: October 2003

A number of 5‐phenyl‐1, 2, 3, 4, 5, 6‐hexahydro‐azepino‐[4, 5‐b]indoles 3 were synthesized with different substituents at the azepine‐N position (methyl‐, allyl‐, 2‐phenyl‐ethyl‐, cyclopropylmethyl‐ and unsubstituted). Furthermore, the indole‐N‐methylated compound was generated and by using norephedrines and norpseudoephedrines as a chiral pool, 4‐methyl‐5‐phenyl‐1, 2, 3, 4, 5, 6‐hexahydro‐azepino‐[4, 5‐b]indoles were prepared which contained racemisation at the reacting C‐atom. These compounds, as well as the ring‐open amino‐alcohols, were screened for their affinity to the hD1‐, hD5‐, hD2L‐, and hD4‐receptors (ç please check sentence). They had micromolar affinities for the receptors and showed the highest affinity to the D1‐subtype family. The cyclic compounds possessed the highest affinity, with the cyclopropylmethyl‐(3c) and methyl‐substituents (3e) being the most active of the tested compounds. Based on an intracellular cAMP‐assay, the unsubstituted compound (at the azepine‐N position) turned out to be an agonist for the D1‐and D5‐subtype family, whereas the substituted compounds showed (partial) agonistic, or even inverse agonistic activity.
The detached eclipsing binary system GX Geminorum
Authors: Sánchez‐Bajo F. , Garrigós‐Sánchez A. , Gómez‐Forrellad J.M. , Nomen‐Torres J. , Kleikamp W. , Frank P. , Moschner W. , Quester W. , García‐Melendo E.
Published: October 2003

Results of the photometric analysis by means of the Wilson‐Devinney method, combined with an empirical massradius relation for LC IV stars support the hypothesis that GX Gem is a well detached evolved system of subgiant stars. The solution is consistent with the known spectroscopic parameters obtained by Popper (1996) and the photometric data of Lacy (2002a). (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new light‐time effect study of AR Aurigae
Authors: Albayrak B. , Ak T. , Elmasli A.
Published: October 2003

A period study of the young binary AR Aur based on the extensive series of published photoelectric/ccd minima times indicates the cyclic (O – C) variation for the system. This continuous oscillatory variation covers almost three cycles, about 6000 orbital periods, by the present observational data. It can be attributed to the light‐time effect due to a third body with a period of 23.68 ± 0.17 years in the system. The analysis yields a light‐time semi‐amplitude of 0.0084 ± 0.0002 day and an orbital eccentricity of 0.20 ± 0.04. Adopting the total mass of AR Aur, the mass of the third body assumed in the co‐planar orbit with the binary is M3 = 0.54 ± 0.03 M⊙ and the semimajor axis of its orbit is a3 = 13.0 + 0.2 AU. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spot modelling of the flare M4.5 dwarf YZ CMi
Authors: Zboril M.
Published: October 2003

We report on a photometric study of the flareM4.5 dwarf YZ CMi as based on photoelectric observations from the seasons 1972/73, 1979/80 and 1996/97. We suggest spot activity to explain the light and colour curves. Spots are generally 500K cooler than the surrounding photosphere and there are basically two solutions available for the observations: high latitude spot changing slightly basic properties such as radius and latitude or active near‐equatorial (belt‐like) centers represented by three spots. However, the activity centers changed in longitudes (∼180°). The typical spot coverage (inclination i = 60°) is 10‐15% and 5% for the season 1996/97 or ∼25% for the stellar inclination i = 75°. As a by‐product, V curve and (V‐I) and (V‐K) indexes turn out to be most promising in modelling of M‐type stars as far as present calibrations are concerned. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sodium enrichment of the stellar atmospheres. II. Galactic Cepheids
Authors: Andrievsky S.M. , Egorova I.A. , Korotin S.A. , Kovtyukh V.V.
Published: October 2003

The present paper is a continuation of our study of the sodium abundance in supergiant atmospheres (Andrievsky et al. 2002a). We present the results on the NLTE abundance determination in Cepheids, and the derived relation between the sodium overabundance and their masses. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Note on the spatial distribution of old open clusters
Authors: Schmidt K.‐H.
Published: October 2003

Using the sample of 74 old open clusters compiled by Friel (1995) the increase of the mean distance from the galactic plane with cluster age has been determined. The result is in a qualitative agreement with the hypothesis of scattering of the clusters during encounters with massive molecular clouds and by spiral arms. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Velocity dispersion in N‐body simulations of CDM models
Authors: Domínguez A.
Published: October 2003

This work reports on a study of the spatially coarse‐grained velocity dispersion in cosmological N‐body simulations (OCDM and ΛCDM models) as a function of time (redshifts z = 0–4) and of the coarsening length (0.6–20 h−1 Mpc). The main result is the discovery of a polytropic relationship ℐ1 ∝ ϱ2–η between the velocity‐dispersion kinetic energy density of the coarsening cells, ℐ1, and their mass density, ϱ. The exponent η, dependent on time and coarsening scale, is a compact measure of the deviations from the naive virial prediction ηvirial = 0. This relationship supports the “polytropic assumption” which has been employed in theoretical models for the growth of cosmological structure by gravitational instability. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flare stars in the TW Hydrae association: the HIP 57269 system
Authors: König B. , Neuhäuser R. , Guenther E. W. , Hambaryan V.
Published: October 2003

We discuss a new member candidate of the TW Hydrae association (TWA) among the stars of the Gershberg et al. (1999) flare star catalog. TWA is one of the closest known associations of young stars at about 60 pc. Three supposedly young flare stars are located in the same region of the sky as TWA. One of them (HIP 57269) shows strong lithium absorption with spectral type K1/K2V and a high level of chromospheric and coronal activity. It is located at a distance of 48.7 ± 6.3 pc in common with the five TWA members observed with Hipparcos (46.7 to 103.9 pc). HIP 57268 A has a wide companion C which also shows lithium absorption at 6707 Å and which has common proper motion with HIP 57269, as well as a close companion resolved visually by Tycho. HIP 57269 A&C lie above the main sequence and are clearly pre‐main‐sequence stars. The UVW‐space velocity is more consistent with the star system being a Pleiades super cluster member. The two other flare stars in the TWA sky region do not show lithium at all and are, hence, unrelated. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An infrared imaging search for low‐mass companions to members of the young nearby β Pic and Tucana/Horologium associations
Authors: Neuhäuser R. , Guenther E.W. , Alves J. , Huélamo N. , Ott Th. , Eckart A.
Published: October 2003

We present deep high dynamic range infrared images of young nearby stars in the Tucana/Horologium and β Pic associations, all ∼10 to 35 Myrs young and at ∼10 to 60 pc distance. Such young nearby stars are well‐suited for direct imaging searches for brown dwarf and even planetary companions, because young sub‐stellar objects are still self‐luminous due to contraction and accretion. We performed our observations at the ESO 3.5m NTT with the normal infrared imaging detector SofI and the MPE speckle camera Sharp‐I. Three arc sec north of GSC 8047‐0232 in Horologium a promising brown dwarf companion candidate is detected, which needs to be confirmed by proper motion and/or spectroscopy. Several other faint companion candidates are already rejected by second epoch imaging. Among 21 stars observed in Tucana/Horologium, there are not more than one to five brown dwarf companions outside of 75 AU (1.5″ at 50 pc); most certainly only ≤5% of the Tuc/HorA stars have brown dwarf companions (13 to 78 Jupiter masses) outside of 75 AU. For the first time, we can report an upper limit for the frequency of massive planets (∼10 Mjup) at wide separations (∼100 AU) using a meaningfull and homogeneous sample: Of 11 stars observed sufficiently deep in β Pic (12 Myrs), not more than one has a massive planet outside of ∼100 AU, i.e. massive planets at large separations are rare (≤9%). (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Proper motion and X‐ray selected search for new members of the young TW Hya association
Authors: Tachihara K. , Neuhäuser R. , Frink S. , Guenther E.
Published: October 2003

We have searched for new members of the TWHya association (TWA) among unidentified ROSAT X‐ray sources by identifying them in proper motion catalogues and selecting those that would be consistent with kinematical membership to the TWA. Spectroscopic follow‐up observations of 19 member candidates revealed the detection of moderate lithium absorption lines for the following three stars: GSC 7206 845, TYC 7216‐55, and TYC 7247‐12. The isochronal ages of the latter TYC stars are estimated to be ∼20 Myr while the other one has ∼100 Myr age based on a kinematic distance estimate that assumes TWA membership. However, the moderately Li‐rich stars are not likely to be new pre‐main sequence members of TWA partly because of the discrepant radial velocities. Infrared follow‐up imaging in the H‐band for the 3 stars shows companion candidates near two of them.While one system (TYC 7216‐55) is probably a near‐equal‐magnitude stellar binary, our follow‐up H‐band spectrum of the faint companion candidate near GSC 7206 845 shows that it is instead a background K‐type star rather than a companion. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A multiple galaxy collision in compact groups
Authors: Tovmassian H.M.
Published: October 2003

It is shown that the dynamical paradox of the HCG 90, which is treated as an old, and at the same time, as a young system (White et al), may be solved assuming that it is a rotating system in which multiple collisions have occurred during Hubble time. In the frames of the same scenario a multiple collisions in SQ (HCG 92) are naturally explained. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A mass ratio limit for primordial black holes
Authors: Brosche P. , Lentes F.‐Th. , Tassie L. J.
Published: October 2003

We augment our scenario for the formation of astronomical objects from macroscopic superstrings by the assumption that the central matter keeps its identity in the fragmentation. From the condition that the angular momentum per mass squared of this matter should be less than the Kerr limit G/c, we obtain upper limits for the ratio of the mass of central black holes M(BH) to the mass M of the host object. This limit is M(BH)/M ≈ 0.001, and, expressed in observed quantities, approximately M(BH)/M ≈ σ2/(v · c) where σ is the r.m.s. velocity, v the rotational velocity and c the velocity of light. The valuesM(BH) agree with the observed behaviour both in order of magnitude and in the variation with velocity dispersion. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hoch hinaus: Schüler forschen unter Weltraumbedingungen II
Authors: Meissner Klaus , Schwertner Jürgen , Hanke Wolfgang
Published: October 2003

Mit Unterstützung des DLR nahmen Stuttgarter Schüler an einer Parabelflugmission teil. Durch ihr Engagement und den erfolgreich durchgeführten Regenwurmversuch haben sie bewiesen, dass derartige Projekte für alle Beteiligten von Vorteil sein können. Die Untersuchung der Schwerkraftabhängigkeit biologischer Systeme wird auch in Zukunft Kernpunkt der Zusammenarbeit zwischen der Universität Hohenheim und dem Wilhelms‐Gymnasium in Stuttgart bleiben.
Die funktionelle Bedeutung der Artenvielfalt: Biodiversität
Authors: Schmid Bernhard
Published: October 2003

Ein Zusammenhang zwischen Artenzahl und Funktionsfähigkeit von Ökosystemen lässt sich nur nachweisen, wenn die Artenzahl in Versuchen experimentell reduziert (oder erhöht) wird. Solche Versuche wurden in den vergangenen zehn Jahren durchgeführt und zeigten zahlreiche positive Effekte der Biodiversität auf Ökosysteme. Die Erklärung für diese Effekte reicht von einem einfachen statistischen Auswahl‐Mechanismus, bei dem artenreiche Systeme mit größerer Wahrscheinlichkeit besonders leistungsfähige, dominante Arten enthalten, bis zu einer vollständigen Arbeitsteilung zwischen Arten, die gemeinsam eine höhere Leistung erbringen können, als es die einzelnen Monokulturen tun würden. Die Wirklichkeit liegt zwischen diesen beiden Extremen und hängt sowohl von der Größe des Biotopraumes wie dem Grad der Nischendifferenzierung zwischen den Arten ab. Die funktionelle Bedeutung der Artenvielfalt stellt ein immenses Potential dar, das in Zukunft auch landwirtschaftlich genutzt werden sollte.
Zwischen glasklar und grauem Star: Augenlinse
Authors: Dahm Ralf
Published: October 2003

Die Linse des Auges ist vollkommen durchsichtig. Durchsichtigkeit ist in der Natur ein sehr seltenes Phänomen, das in den meisten Fällen auf einer von zwei Anpassungen beruht: Das durchsichtige Gewebe ist sehr dünn oder es besteht fast nur aus Wasser. Die Linse musste andere Wege finden, um durchsichtig zu werden. Ihre Zellen sind außerordentlich hoch spezialisiert, um Licht ungehindert durchfallen zu lassen. Doch diese Spezialisierung birgt auch immer die Gefahr, dass die Zellen sich trüben und ein grauer Star entsteht. Graue Stare können das Sehvermögen stark einschränken. Sogar das Werk des Impressionisten Claude Monet wurde nachhaltig durch seine getrübten Linsen beeinflusst. Die einzige Möglichkeit, graue Stare zu behandeln ist die operative Entfernung der Linse.
Das Kambrium: Als das Leben „explodierte”︁ und eine völlig neue Welt entstand
Authors: Elicki Olaf
Published: October 2003

Das Kambrium repräsentiert den frühesten Zeitabschnitt der Erdgeschichte, welcher uns durch die Überlieferung von Fossilien eine detaillierte Rekonstruktion der damaligen Lebens‐ und Sedimentationsräume ermöglicht. Nach oberproterozoischen Vereisungsphasen stellte sich mit dem Kambrium ein „warm house”︁‐Klima ein; bedeutende globale Meeresspiegelanstiege und paläogeographische Veränderungen schufen den Rahmen für die „Kambrische Explosion”︁. Während dieser innovativsten Phase der Evolution erschienen innerhalb eines geologische relativ kurzen Zeitraumes alle heute bekannten (zuzüglich kurz darauf wieder erloschener) tierischen Baupläne — einschließlich der ersten Chordaten. Diese explosionsartige Diversifizierung der Lebewelt führte zu grundlegenden Neustrukturierungen globaler Stoffkreisläufe und veränderte die Sphären unseres Planeten nachhaltig. Mit dem Einsetzen des Kambriums entstanden die uns heute noch vertrauten Grundmuster ökologischer Zusammenhänge sowie — mit der Räuber‐Beute‐Beziehung — ein neuer hocheffizienter Evolutionsmotor.
Weltweites Netzwerk von Baumkronen‐Observatorien
Authors: Irsch Wilhelm
Published: October 2003

Die Artenvielfalt in den Baumkronen der Wälder ist immens. Ein weltweites Netzwerk aus 20 Baumkronen‐Observatorien soll in den kommenden 20 Jahren die Biodiversität und die Auswirkungen der globalen Veränderungen in den Baumkronen beobachten.
Magenbakterium mit Langstreckenwaffe
Authors: Gebert Bettina
Published: October 2003

Das Bakterium Helicobacter pylori nistet sich in die Magenschleimhaut ein und löst eine meist symptomlose Gastritis aus. Etwa 50 Prozent der Weltbevölkerung sind chronisch mit H. pylori infiziert, 15 bis 20 Prozent der Infizierten entwickeln im Laufe der Jahre Folgekrankheiten wie Magen‐ und Zwölffingerdarmgeschwüre oder ein Magenkarzinom. Weitgehend unverstanden war bisher die Frage, warum H. pylori den Magen auf Dauer besiedeln kann und nicht durch das Immunsystem eliminiert wird. Forscher am Max‐von‐Pettenkofer Institut für Hygiene und Medizinische Mikrobiologie in München fanden heraus, dass ein Toxin von H. pylori die Aktivierung der T‐Zellen hemmt.
Zum Fressen gern
Authors: Wendler Silke
Published: October 2003

Üblicherweise werden Hochzeitsgeschenke wie bereits fertig gestellte Nester, Beutetiere oder Drüsensekrete von den Männchen dargeboten. Bei dem Wasserläufer Phoreticovelia disparata, der tropische Flüsse Australiens bewohnt, ist das anders: Hier füttern die Weibchen die Männchen durch.
Anpassungen und Vielfalt im Pikoplankton
Authors: Brennicke Axel
Published: October 2003

Als „Pikoplankton”︁ werden die kleinsten photosynthetisch aktiven Bewohner der Meere bezeichnet. Erst vor gut zwanzig Jahren wurden diese enorm wichtigen Zwerge entdeckt, die den Anfang der Nahrungskette im Meer bilden. Die jetzt veröffentlichten vollständigen Genomsequenzen von verschiedenen Vertretern dieser Bakterien zeigen eine erstaunliche genetische Anpassung der Winzlinge an die Lebensbedingungen in unterschiedlichen Wassertiefen durch Mutation, Genverdoppelung und sogar durch Transfer von genetischen Informationen zwischen verschiedenen Spezies.
Karl August Möbius und Friedrich Dahl
Authors: Buschbaum Christian , Saier Bettina , Reise Karsten
Published: October 2003

„Biozönose”︁ und „Biotop”︁ sind heute für jeden Biologiestudenten feste Begriffe und haben spätestens mit der Umweltbewegung in den 1980er Jahren auch Einzug in unsere Umgangssprache gefunden. Ihr Ursprung geht aber weit zurück und ist untrennbar mit dem deutschen Lehrer und Zoologen Karl August Möbius und seinem Schüler Friedrich Dahl verbunden.
Gap junctions in the inner ear: Comparison of distribution patterns in different vertebrates and assessement of connexin composition in mammals
Authors: Forge Andrew , Becker David , Casalotti Stefano , Edwards Jill , Marziano Nerissa , Nevill Graham
Published: October 2003

The distribution and size of gap junctions (GJ) in the sensory epithelia of the inner ear have been examined in a reptile (gecko), birds (chicken and owl), and mammals (mouse, guinea pig, gerbil, and bat), and the connexin composition of GJs in the mammalian inner ear has been assessed. Freeze fracture revealed a common pattern of GJ distribution in auditory and vestibular sensory epithelia in the different vertebrate classes. In all these tissues, GJs are numerous, often occupying more than 25% of the plasma membrane area of supporting cells and sometimes composed of more than 100,000 channels. Screening for 12 members of the connexin family in the mammalian inner ear by RT‐PCR, Western blotting, and immunohistochemistry revealed four connexin isotypes, cx26, cx30, cx31, and cx43, in the cochlea and three, cx26, cx30, and cx43, in the vestibular organs. With antibodies characterised for their specificity, cx26 and cx30 colocalised in supporting cells of the organ of Corti, in the basal cell region of the stria vascularis, and in type 1 fibrocytes of the spiral ligament. No other connexin was detected in these regions. Cx31 was localised among type 2 fibrocytes below the spiral prominence, a region where cx30 was not expressed and cx26 expression appeared to be low. Cx43 was detected only in the region of “tension fibrocytes” lining the inner aspect of the otic capsule. This suggests separate functional compartments in the cochlea. In addition to cx26 and cx30, cx43 was detected in supporting cells of the vestibular sensory epithelia. Where cx26 and cx30 were colocalised, double immunogold labelling of thin sections showed both cx26 and cx30 evenly distributed in individual GJ plaques, a pattern consistent with the presence of heteromeric connexons. Coimmunoprecipitation of cochlear membrane proteins solubilised with a procedure that preserves the oligomeric structure of connexons confirmed the presence of heteromeric cx26/cx30 connexons. Heteromeric cx26/cx30 connexons may be unique to the inner ear, which could be one factor underlying the non‐syndromic character of the deafness caused by mutations in cx26. J. Comp. Neurol. 467:207–231, 2003. © 2003 Wiley‐Liss, Inc.
Localization of trigeminal, spinal, and reticular neurons involved in the rat blink reflex
Authors: Zerari‐Mailly Fawzia , Dauvergne Céline , Buisseret Pierre , Buisseret‐Delmas Catherine
Published: October 2003

Electrical stimulation of the supraorbital nerve (SO) induces eyelid closure by activation of orbicularis oculi muscle motoneurons located in the facial motor nucleus (VII). Neurons involved in brainstem central pathways implicated in rat blink reflex were localized by analyzing c‐Fos protein expression after SO stimulation in conjunction with tracing experiments. A retrograde tracer (gold‐horseradish peroxidase [HRP]) was injected into the VII. The distribution patterns of activated c‐Fos‐immunoreactive neurons and of neurons exhibiting both c‐Fos immunoreactivity and gold‐HRP labeling were determined in the sensory trigeminal complex (STC), the cervical spinal cord (C1), and the pontomedullary reticular formation. Within the STC, c‐Fos immunoreactivity labeled neurons in the ipsilateral ventral part of the principal nucleus, the pars oralis and interpolaris, and bilaterally in the pars caudalis. Colocalization of gold‐HRP and c‐Fos immunoreactivity was observed in neurons of ventral pars caudalis layers I–IV and ventral pars interpolaris. In C1, SO stimulation revealed c‐Fos neurons in laminae I–V. After additional injections in VII, the double‐labeled c‐Fos/gold‐HRP neurons were concentrated in laminae IV and V. Although c‐Fos neurons were found throughout the pontomedullary reticular formation, most appeared rostrally around the motor trigeminal nucleus and in the ventral parvocellular reticular nucleus medial to the fiber bundles of the seventh nerve. Caudally, c‐Fos neurons were in the lateral portion of the dorsal medullary reticular field. In addition, these reticular areas contained double‐labeled neurons in electrically stimulated rats that had received gold‐HRP injections in the VII. The presence of double‐labeled neurons in the STC, C1, and the reticular formation implies that these neurons receive sensory information from eyelids and project to the VII. These double‐labeled neurons could then be involved in di‐ or trisynaptic pathways contributing to the blink reflex. J. Comp. Neurol. 467:173–184, 2003. © 2003 Wiley‐Liss, Inc.
Distribution and development of calretinin‐like immunoreactivity in the telencephalon of the brown trout, Salmo trutta fario
Authors: Castro Antonio , Becerra Manuela , Manso María Jesús , Anadón Ramón
Published: October 2003

Immunocytochemical techniques were used to investigate the distribution of calretinin (CR) in the telencephalon of adult and developing brown trout (Salmo trutta fario L.). Previous immunoblotting analysis of trout brain extracts with a CR antibody revealed a single protein band of 29 kDa, similar to that observed in rat brain extracts. In the forebrain of adult trout, CR immunoreactivity was distributed in well‐defined cell groups, which allowed us to analyze the CR‐immunoreactive (ir) neuronal populations in terms of their respective regions of origin. Our results show that the CR‐ir populations of the dorsal and ventral telencephalon are differentially distributed along the rostrocaudal axis, indicating the existence of four main populations of pallial origin and several ventral (subpallial) populations. A highly specific pattern of innervation by CR‐ir fibers of different telencephalic regions was observed from alevins to adults. The first CR‐ir cell groups of the telencephalic hemispheres were observed in the ventral telencephalic area and preoptic region of 7–8‐mm embryos. In later embryos and in alevins, further CR‐ir cell groups appeared in the ventral and dorsal telencephalic areas, showing a dorsoventrally banded pattern at precommissural levels. Study of CR expression provided new criteria for understanding the organization of the telencephalon of trout, and hence of teleosts. J. Comp. Neurol. 467:254–269, 2003. © 2003 Wiley‐Liss, Inc.
Conserved and convergent organization in the optic lobes of insects and isopods, with reference to other crustacean taxa
Authors: Sinakevitch I. , Douglass J.K. , Scholtz G. , Loesel R. , Strausfeld N.J.
Published: October 2003

The shared organization of three optic lobe neuropils—the lamina, medulla, and lobula—linked by chiasmata has been used to support arguments that insects and malacostracans are sister groups. However, in certain insects, the lobula is accompanied by a tectum‐like fourth neuropil, the lobula plate, characterized by wide‐field tangential neurons and linked to the medulla by uncrossed axons. The identification of a lobula plate in an isopod crustacean raises the question of whether the lobula plate of insects and isopods evolved convergently or are derived from a common ancestor. This question is here investigated by comparisons of insect and crustacean optic lobes. The basal branchiopod crustacean Triops has only two visual neuropils and no optic chiasma. This finding contrasts with the phyllocarid Nebalia pugettensis, a basal malacostracan whose lamina is linked by a chiasma to a medulla that is linked by a second chiasma to a retinotopic outswelling of the lateral protocerebrum, called the protolobula. In Nebalia, uncrossed axons from the medulla supply a minute fourth optic neuropil. Eumalacostracan crustaceans also possess two deep neuropils, one receiving crossed axons, the other uncrossed axons. However, in primitive insects, there is no separate fourth optic neuropil. Malacostracans and insects also differ in that the insect medulla comprises two nested neuropils separated by a layer of axons, called the Cuccati bundle. Comparisons suggest that neuroarchitectures of the lamina and medulla distal to the Cuccati bundle are equivalent to the eumalacostracan lamina and entire medulla. The occurrence of a second optic chiasma and protolobula are suggested to be synapomorphic for a malacostracan/insect clade. J. Comp. Neurol. 467:150–172, 2003. © 2003 Wiley‐Liss, Inc.
EUROCVD‐14 and CVD XVI
Authors: Krumdieck S.
Published: October 2003

One of the largest CVD conferences ever held with over 230 papers and numerous posters was the combined fourteenth EUROCVD‐14 and sixteenth international CVD conferences held in Paris are in the focus of this essay. The author does not only give an overview of sessions and highlights but also brings the atmosphere of the conference alive.
Low‐Pressure Metal–Organic Chemical Vapor Deposition of Transparent and p‐Type Conducting CuCrO2 Thin Films with High Conductivity
Authors: Mahapatra S. , Shivashankar S.A.
Published: October 2003

The growth of CuCrO2 films on glass substrate by LP‐MOCVD is reported. Unlike nearly all transparent conducting oxides which exhibit only n‐type conductivity, CuCrO2 crystalline thin films deposited from Cu(acac)2 and Cr(acac)3 precursors exhibit positive Hall co‐efficient with the highest carrier Hall mobility reported to date for any p‐type transparent conducting oxide based on Cu‐delafossite structure. The deposition, performed at 823 K, grows at a rate of 13 nm min–1. XRD analysis indicates diffraction peaks corresponding to the (101), (012), (104), and (110) planes. The direct optical bandgap is calculated to be 3.08 eV.
Structure and Unusual Substitution Reaction of Oligoether‐Appended β‐Diketonato Strotium Complex
Authors: Min Y.‐S. , Cho Y.J. , Lee J.‐H. , Kim D. , Yoon I. , Park K.‐M. , Lee S.S. , Cho B.R.
Published: October 2003

The structure of a potential strontium MOCVD precursor is studied. Sr(methd)2 [methd = 1‐(2‐methoxyethoxy)‐2,2,6,6‐tetramethyl‐3,5‐heptadionate], an oligoether‐appended strontium complex is shown to be a dimer in solution and liquid state. However, the complex is converted to another dimer during crystallization. A plausible equilibrium mechanism for this reaction is proposed (see Figure).
Growth of Praseodymium Oxide Thin Films by Liquid Injection MOCVD Using a Novel Praseodymium Alkoxide Precursor
Authors: Aspinall H.C. , Gaskell J. , Williams P.A. , Jones A.C. , Chalker P.R. , Marshall P.A. , Bickley J.F. , Smith L.M. , Critchlow G.W.
Published: October 2003

Praseodymium oxide thin films are prepared using a new volatile precursor (for structure of precursor LiCl complex, see Figure) by liquid injection MOCVD. The oxide, a wide‐bandgap (3.9 eV) and high‐κ material, which is currently being investigated as a possible alternative to SiO2 films in silicon‐based field‐effect transistors, is deposited from [Pr(mmp)3] (mmp = OCMe2CH2OMe) in the presence of oxygen over the temperature range 350–600 °C.