bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycoconjugates of the urodele amphibian testis shown by lectin cytochemical methods
Authors: Sáez Francisco José , Madrid Juan Francisco , Cardoso Sergio , Gómez Laura , Hernández Francisco 
Published: July 2004

AbstractLectin histochemistry is a useful method that allows the in situ identification of the terminal sugar moieties of the carbohydrates that form the glycoconjugates. Moreover, when it is combined with chemical or enzymatic deglycosylation pretreatments, lectin histochemistry can be employed to determine if carbohydrates are linked to the protein core by means of an N‐ or O‐glycosidic linkage or, indeed, to partially sequence the sugar chains. One of the most interesting model organs for the study of spermatogenesis is the amphibian urodele testis. However, this organ has not been very widely investigated with lectin histochemical research. In the last few years, we have carried out a research project to identify and locate glycoconjugates in the testis of the urodele Pleurodeles waltl, the Spanish newt, as a first approach to identify possible carbohydrates with key roles in spermatogenesis. Our findings reveal some glycan chains located in a fusome‐like structure in early (diploid) germ cells, oligosaccharides with terminal GalNAc in the acrosome, the occurrence of glycan modifications in the acrosomal contents during spermiogenesis, and changes in glycan composition of follicle and interstitial cells during the spermatogenetic cycle. Furthermore, the similar labeling pattern of follicle and duct cells supports the hypothesis for a common origin of both cell types. Microsc. Res. Tech. 64:63–76, 2004. © 2004 Wiley‐Liss, Inc.
When did theropods become feathered?—evidence for pre‐archaeopteryx feathery appendages
Authors: Kundrát Martin 
Published: July 2004

AbstractFilamentous impressions associated with locomotive theropod tracks in the Lower Jurassic Turners Falls Formation of western Massachusetts, U.S.A. represent the oldest evidence of feathered dinosaurs. Feather impressions are preserved with sitting traces which bear integumentary structures along the outlines of the pre‐pubic and ischiadic impressions. Extant palaeognathous down feathers provide a valuable comparative model for these filamentous integumental structures and for similar structures described in Chinese theropods from younger deposits. The described morphologies are congruent with Stage II of Prum ('99) and support that plumulaceous morphologies evolved before the origin of the rhachis and the planar vane. Appearance of feathery appendages in theropods may be linked to evolution of higher metabolic rates, improved locomotory abilities, and/or distinct behavior(s) and visual communication. Development of feathery integument might have also played a crucial role in the competitiveness and successful radiation of maniraptoriform theropods and their actively flying descendants in the Jurassic. J. Exp. Zool. (Mol. Dev. Evol.) 302B:355–364, 2004. © 2004 Wiley‐Liss, Inc.
Preliminary observations on the spawning conditions of the European amphioxus (Branchiostoma lanceolatum) in captivity
Authors: Fuentes Michael , Schubert Michael , Dalfo Diana , Candiani Simona , Benito Elia , Gardenyes Josep , Godoy Laura , Moret Frederic , Illas Margarita , Patten Iain , Permanyer Jon , Oliveri Diana , Boeuf Gilles , Falcon Jack , Pestarino Mario , Fernandez Jordi Garcia , Albalat Ricard , Laudet Vincent , Vernier Philippe , Escriva Hector 
Published: July 2004

AbstractMembers of the subphylum Cephalochordata, which include the genus Branchiostoma (i.e. amphioxus), represent the closest living invertebrate relatives of the vertebrates. To date, developmental studies have been carried out on three amphioxus species (the European Branchiostoma lanceolatum, the East Asian B. belcheri, and Floridian‐Caribbean B. floridae). In most instances, adult animals have been collected from the field during their ripe season and allowed (or stimulated) to spawn in the laboratory. In any given year, dates of laboratory pawning have been limited by two factors. First, natural populations of these three most studied species of amphioxus are ripe, at most, for only a couple of months each year and, second, even when apparently ripe, animals spawn only at unpredictable intervals of every several days. This limited supply of living material hinders the development of amphioxus as a model system because this limitation makes it more difficult to work out protocols for new laboratory techniques. Therefore we are developing laboratory methods for increasing the number of amphioxus spawning dates per year. The present study found that a Mediterranean population of B. lanceolatum living near the Franco‐Spanish border spawned naturally at the end of May and again at the end of June in 2003. Re‐feeding experiments in the laboratory demonstrated that the gonads emptied at the end of May refilled with gametes by the end of June. We also found that animals with large gonads (both, obtained from the field and kept and fed at the laboratory during several weeks) could be induced to spawn in the laboratory out of phase with the field population if they were temperature shocked (spawning occurred 36 hours after a sustained increase in water temperature from 19°C to 25°C). J. Exp. Zool. (Mol. Dev. Evol.) 302B:384–391, 2004. © 2004 Wiley‐Liss, Inc.
The integration of Darwinism and evolutionary morphology: Alexej Nikolajevich Sewertzoff (1866–1936) and the developmental basis of evolutionary change
Authors: Levit George S. , Hoβfeld Uwe , Olsson Lennart 
Published: July 2004

AbstractThe growth of evolutionary morphology in the late 19th and early 20th centuries was inspired by the work of Carl Gegenbaur (1826–1903) and his protégé and friend Ernst Haeckel (1834–1919). However, neither of them succeeded in creating and applying a strictly Darwinian (selectionist) methodology. This task was left to the next generation of evolutionary morphologists. In this paper we present a relatively unknown researcher, Alexej Nikolajevich Sewertzoff (1866–1936) who made important contributions towards a synthesis of Darwinism and evolutionary morphology. J. Exp. Zool. (Mol Dev. Evol.) 302B:343–354, 2004. © 2004 Wiley‐Liss, Inc.
Molecular evolution in the yeast transcriptional regulation network
Authors: Evangelisti Annette M. , Wagner Andreas 
Published: July 2004

AbstractWe analyze the structure of the yeast transcriptional regulation network, as revealed by chromatin immunoprecipitation experiments, and characterize the molecular evolution of both its transcriptional regulators and their target (regulated) genes. We test the hypothesis that highly connected genes are more important to the function of gene networks. Three lines of evidence—the rate of molecular evolution of network genes, the rate at which network genes undergo gene duplication, and the effects of synthetic null mutation in network genes—provide no strong support for this hypothesis. In addition, we ask how network genes diverge in their transcriptional regulation after duplication. Both loss (subfunctionalization) and gain (neofunctionalization) of transcription factor binding play a role in this divergence, which is often rapid. On the one hand, gene duplicates experience a net loss in the number of transcription factors binding to them, indicating the importance of losing transcription factor binding sites after gene duplication. On the other hand, the number of transcription factors that bind to highly diverged duplicates is significantly greater than would be expected if loss of binding played the only role in the divergence of duplicate genes. J. Exp. Zool. (Mol. Dev. Evol.) 302B:392–411, 2004. © 2004 Wiley‐Liss, Inc.
Dermo‐epidermal interactions in reptilian scales: Speculations on the evolution of scales, feathers, and hairs
Authors: Alibardi Lorenzo 
Published: July 2004

AbstractThe dermal influence on the epidermis during scale formation in reptiles is poorly known. Cells of the superficial dermis are not homogeneously distributed beneath the epidermis, but are instead connected to specific areas of the epidermis. Dermal cells are joined temporarily or cyclically through the basement membrane, with the reactive region of the epidermis forming specific regions of dermo‐epidermal interactions. In these regions morphoregulatory molecules may be exchanged between the dermis and the connected epidermis. Possible changes in the localization of these regions in the skin may result in the production of different appendages, in accordance with the genetic makeup of the epidermis in each species. Regions of dermo‐epidermal interactions seem to move their position during development. A hypothesis on the development and evolution of scales, hairs, and feathers from sarcopterigian fish to amniotes is presented, based on the different localization and extension of regions of dermo‐epidermal interactions in the skin. It is hypothesized that, during phylogenesis, possible variations in the localization and extension of these regions, from the large scales of basic amniotes to those of sauropsid amniotes, may have originated scales with hard (beta)‐keratin. In extant reptiles, extended regions of dermo‐epidermal interaction form most of the expanse of outer scale surface. It is hypothesized that the reduction of large regions of dermo‐epidermal interactions into small areas in the skin were the origin of dermal condensations. In mammals, small regions of dermo‐epidermal interactions have invaginated, forming the dermal papilla with the associated hair matrix epidermis. In birds, small regions of dermo‐epidermal interactions have reduced the original scale surface of archosaurian scales, forming the dermal papilla. The latter has invaginated in association with the collar epidermis from which feathers were produced. J. Exp. Zool. (Mol. Dev. Evol.) 302B:365–383, 2004. © 2004 Wiley‐Liss, Inc.
Labelling, purification, and receptor affinity of radioactive iododiethylstilbestrol (*I‐DES) with high specific activity and first structure analysis with natI‐DES
Authors: Fischer Thomas , Schomäcker Klaus , Schicha Harald 
Published: July 2004

AbstractDiethylstilbestrol 1 is a well known, non‐steroidal estrogen with high affinity for the estrogen receptor (ER). When labelled with an Auger‐electron emitter such as 123I, 125I or 77Br 1 would be an useful radiopharmaceutical for therapy of ER‐positive mamma tumours. In the present work 1 was labelled easily and quickly with iodine by a modified chloramin T method (methanolic instead of aqueous solution), which leads to the desired product 2 in good yields (50–74%), with high radiochemical purity (>98%) and – in opposite to former attempts – very high specific activities (123I‐DES: 8800 TBq/mmol, 125I‐DES: 80 TBq/mmol, 131I‐DES: 870 TBq/mmol). After separation by RP‐HPLC all products were characterized by NMR‐techniques (1H‐, 13C‐NMR, H,H‐COSY, and HMBC) for the very first time and the main product 3′‐Iodo‐DES 2 as well as some by‐products like the p‐toluol‐sulfonic acid amide 3, 1, and 1‐chloro‐1‐(4′‐hydroxy‐phenyl)‐propene‐1 4 could be identified. The complex dissociation constant for 125I‐DES with ER was determined by Scatchard plot and is comparable with that of 16α‐[125I]‐iodoestradiol (125I‐DES: KD=(2.67±1.02) × 10−9 mol/l, 16α‐[125I]‐iodoestradiol: KD=(3.92±2.27) × 10−9 mol/l). Copyright © 2004 John Wiley & Sons, Ltd.
An analysis of Icelandic climate since the nineteenth century
Authors: Hanna Edward , Jónsson Trausti , Box Jason E. 
Published: July 2004

AbstractNew, long monthly series of Icelandic air pressure, temperature, precipitation and sunshine data are presented and analysed to determine possible evidence of recent climatic changes in Iceland. Climatic series are compared with the North Atlantic oscillation (NAO) indices; Icelandic temperature and precipitation are moderately but significantly correlated with the NAO. An updated south–north Iceland temperature index is discussed in relation to 20th century reductions in sea‐ice coverage. Net warming over Iceland occurred over all long‐term records from the mid19th century to the present, consistent with observed global warming trends, but superimposed on this was a marked cooling between the 1940s and early 1980s; Icelandic warming resumed around 1985. The mid–late 20th century cooling is in agreement with observed cooling in southern Greenland, suggesting that large‐scale changes in atmospheric circulation were probably responsible. The 1930s was the warmest decade of the 20th century in Iceland, in contrast to the Northern Hemisphere land average. There was a distinct 20th century dipole in temperatures between Iceland and northwestern Europe, with 1941 serving as an extreme year, i.e. cold Europe and warm Iceland and Greenland. There are also signs of a precipitation increase since the late 19th century, although this is significant for only one out of three stations. Moreover, precipitation rates exhibit a positive correlation with temperature. There were no statistically significant overall long‐term changes in pressure or sunshine duration. However, there are statistically significant negative correlations of precipitation with the sunshine data. There is evidence of possible solar forcing of Icelandic temperature and pressure. Results from the analysis aid our understanding of recent and ongoing changes in Icelandic and North Atlantic climate. The results should help us interpret these changes in the context of larger scale atmospheric/subpolar variability and future climate‐change predictions. Copyright © 2004 Royal Meteorological Society
REGEOTOP: New climatic data fields for East Asia based on localized relief information and geostatistical methods
Authors: Thomas Axel , Herzfeld Ute C. 
Published: July 2004

AbstractClimate data fields represent essential tools for climate, biogeographical and agricultural research to run models and to provide observational data for the verification of global climate models (GCM). Climate data fields are generated through interpolation of observations taken at meteorological stations. Most current interpolation procedures try to describe the influence of topography on spatial climatic variations by relating them directly to absolute elevation or by introducing simple relief variables such as exposure. In both cases this may not properly describe spatial climatic variations, particularly not those of precipitation.This paper describes a regionalization procedure (REGEOTOP) that was applied to generate monthly spatial climatic data fields of temperature, precipitation and potential evapotranspiration (1951–90) for East Asia at 0.25° resolution from a new climate data base. REGEOTOP proceeds in several steps, combining statistical and geostatistical methods. First, basic relief types are determined by application of principal component analysis to moving windows in a digital elevation model (DEM) of the study area. Second, climatic variables are related to relief parameters by regression analysis with respect to basic relief types, location, and elevation. To account for large‐scale variation of climate variables, geostatistical variogram analysis (step three) and interpolation (step four) are applied to the regression residuals. Finally, maps of regression estimates plus kriged residuals are calculated, for a total of 1440 cases.The relief parameterization retains about 90% of the variance of a DEM in 10–18 principal components, depending on input parameters. The REGEOTOP method is computationally expensive, but results justify the effort. Owing to the thorough analysis in the REGEOTOP method and its application to the most comprehensive climate databases that exist outside China to date, the resultant maps provide a solid basis for GCM verification or hydrological and agro‐ecologic investigations and prognoses for East Asia. Copyright © 2004 Royal Meteorological Society
Occurrence and quantity of precipitation can be modelled simultaneously
Authors: Dunn Peter K. 
Published: July 2004

AbstractMany statistical models exist for modelling precipitation. One difficulty is that two issues need to be addressed: the probability of precipitation occurring, and then the quantity of precipitation recorded. This paper considers a family of distributions for modelling the quantity of precipitation, including those observations in which exactly no precipitation is recorded. Two examples are then discussed showing the distributions model the precipitation patterns well. Copyright © 2004 Royal Meteorological Society
Vegetation as an urban climate control in the subtropical city of Gaborone, Botswana
Authors: Jonsson Per 
Published: July 2004

AbstractThe influence of vegetation on the urban climate was studied in the subtropical city Gaborone, the rapidly expanding capital of Botswana with approximately 200 000 inhabitants. Temperature records from an urban and a rural station were analysed for the period 1985–96. In an attempt to explain possible seasonal change in vegetation, NOAA satellite normalized difference vegetation index imagery was analysed. The present urban influence was investigated with temperature loggers at selected urban and rural sites. In addition, mobile measurements revealed spatial patterns in temperature and humidity for different land uses.Seasonal patterns of urban–rural differences in minimum temperatures emerge during the period 1994–96, especially during the winter when the heat island effect is largest. It is shown that differences in urban and rural vegetation over the year partly explain this variation. Mobile measurements reveal a weak nocturnal heat island of 2–3 °C during clear and calm nights. There are intra‐urban temperature differences that are in the same range as the urban–rural relationship due to the role of vegetation. Evapotranspiration lowers the temperature, which was detected by high humidity in areas of lush vegetation. This becomes apparent at midday, when densely vegetated areas were up to 2 °C cooler than rural sites. An oasis effect, therefore, only exists on a highly local basis. In contrast, parts of the city with sparse vegetation are warmer than the countryside.There is an apparent opposed effect of rural and urban vegetation, whereby the former is hindering the temperature from falling and the latter is cooling the environment through evapotranspiration. This can be explained by the overwhelming amounts of imported water in the city promoting evaporative cooling. Copyright © 2004 Royal Meteorological Society
Skill assessment of the existing capacity for extended‐range weather forecasting in Nigeria
Authors: Adejuwon James O. , Odekunle Theophilus O. 
Published: July 2004

AbstractThe need for skilful weather forecasting as a strategy for adapting food production to a variable and changing climate is recognized. Frequent assessment of the existing tools provides the needed feedback to encourage the growth of a more reliable weather forecasting capacity. A scheme designed for the assessment of the skill demonstrated by published weather forecasts is presented. The existing products of four weather forecasting organizations with interests in West Africa are assessed using the observed weather during the period from 1996 to 2000. The weather forecasting organizations concerned are NOAA (USA), Met Office (UK), CNRS (France) and the Nigerian Central Forecasting Office. The forecast skills of the various organizations appear not to have witnessed any significant improvement between 1996 and 2000. Overall, the low proportion of the forecasts falling into the ‘low skill’ category is encouraging. However, the relatively high percentage of the ‘moderate skill’ and low percentage of the ‘high skill’ categories suggest that there is considerable room for improvement. One may have to give the various organizations more time to perfect the existing tools. However, this review has not come too early, because it is the type of feedback needed to hasten the emergence of more skilful forecasts. It has been established in this study that better rainfall forecasts could be achieved with higher resolution sea‐surface temperature anomaly data and the inclusion of more predictor variables, especially those of a synoptic nature. Copyright © 2004 Royal Meteorological Society.
Impact of the North Atlantic oscillation on winter convection: convective precipitation and cloud‐to‐ground lightning
Authors: Rivas Soriano Luis , De Pablo Fernando , Tomas Clemente 
Published: July 2004

AbstractThe relationship between the North Atlantic oscillation (NAO) and winter (November to March) convection is analysed using two convective parameters: convective precipitation (CP) and cloud‐to‐ground (CG) lightning. Using winter CP values from 1950 to 2000 over the North Atlantic and western European area (30–70 °N, 60 °W–10 °E), positive correlations were found between the NAO index values and CP at latitudes higher than ∼50 °N, whereas negative correlations were found for latitudes lower than 50 °N. The spatial pattern of correlation coefficients at latitudes higher (lower) than ∼50 °N suggests that the advection of temperature (moisture) is the main factor contributing to the relationship between the NAO and CP. The NAO accounts for 47% (25%) of the first principal component of CP interannual variance at latitudes higher (lower) than 50 °N.The monthly winter CG lightning‐flash density for 9 years (1992–2000) over the Iberian Peninsula was analysed in relation to the NAO on a small spatial scale (0.4° longitude × 0.4° latitude). The results were consistent with those found for the CP over the same zone. The correlation coefficient between the monthly NAO index value and the monthly CG flash number is r = −0.6, suggesting a relationship between them. Spatial variations in this relationship were also studied. The results indicated that the impact of the NAO on CG lightning is stronger on the western Iberian Peninsula and decreases eastwards. Copyright © 2004 Royal Meteorological Society