bluuebunny/crossref_metadata_2025_split huggingface dataset:
The geographical structure of British bird distributions: diversity, spatial turnover and scale
Authors: Lennon Jack J. , Koleff Patricia , GreenwooD J. J. D. , Gaston Kevin J. 
Published: March 2003

Summary

Using data on the spatial distribution of the British avifauna, we address three basic questions about the spatial structure of assemblages: (i) Is there a relationship between species richness (alpha diversity) and spatial turnover of species (beta diversity)? (ii) Do high richness locations have fewer species in common with neighbouring areas than low richness locations?, and (iii) Are any such relationships contingent on spatial scale (resolution or quadrat area), and do they reflect the operation of a particular kind of species–area relationship (SAR)?
For all measures of spatial turnover, we found a negative relationship with species richness. This held across all scales, with the exception of turnover measured as βsim.
Higher richness areas were found to have more species in common with neighbouring areas.
The logarithmic SAR fitted better than the power SAR overall, and fitted significantly better in areas with low richness and high turnover.
Spatial patterns of both turnover and richness vary with scale. The finest scale richness pattern (10 km) and the coarse scale richness pattern (90 km) are statistically unrelated. The same is true of the turnover patterns.
With coarsening scale, locations of the most species‐rich quadrats move north. This observed sensitivity of richness ‘hotspot’ location to spatial scale has implications for conservation biology, e.g. the location of a reserve selected on the basis of maximum richness may change considerably with reserve size or scale of analysis.
Average turnover measured using indices declined with coarsening scale, but the average number of species gained or lost between neighbouring quadrats was essentially scale invariant at 10–13 species, despite mean richness rising from 80 to 146 species (across an 81‐fold area increase). We show that this kind of scale invariance is consistent with the logarithmic SAR.
Tragedy of the commons as a result of root competition
Authors: Gersani Mordechai , Brown Joel s. , O'Brien Erin E. , Maina Godfrey M. , Abramsky Zvika 
Published: March 2003

Summary

We develop and test a game‐theoretic model for considering the effects of intra‐ and interplant competition on root proliferation and reproductive yield.
We predict that if space and resources per individual are held constant, plants should produce more roots per individual and less reproductive yield per individual as the number of plants sharing the combined space increases.
We tested the predictions using soybean plants (Glycine max) cultivated in the glasshouse either as owners or as two individuals sharing twice the space and nutrients.
Sharing individuals produced 85% more root mass than owners. Owners, however, produced 30% more reproductive yield per plant (dry mass of seeds), as a result of significantly more seed pods (8.70 vs. 7.66), more seeds per pod (1.87 vs. 1.72) and larger seeds (0.205 vs. 0.195 g seed−1), than did sharing individuals.
Total plant biomass did not differ between owners and sharing individuals, but owners had significantly higher shoot to root ratios, produced significantly more seeds per unit root mass, and allocated a significantly higher percentage of total biomass production to seeds.
Possession of an evolutionarily stable strategy (ESS) of root competition suggests that different roots and parts of a plant assess and respond to opportunities in a manner that maximizes the good of the whole plant. Thus, plants may be more sophisticated and share more in common with animals in their non‐cognitive behaviours than previously thought. A plant operating as a co‐ordinated whole should, all else being equal, first proliferate roots in unoccupied soil, then in soil occupied by a conspecific competitor, and lastly in soil already occupied by its own roots.
Comparative study of a block copolymer morphology by transmission electron microscopy and scanning force microscopy
Authors: Ott H. , Abetz V. , Altstädt V. , Thomann Y. , Pfau A. 
Published: March 2003

SummaryUsing transmission electron microscopy (TEM) and scanning force microscopy (SFM) together, it was possible to verify important structural features of a nanostructured bulk material such as the kp‐morphology in an ABC triblock copolymer. By applying suitable imaging techniques during the SFM measurements it was possible to determine the morphology without additional manipulation steps in between. In comparison, TEM investigations on this type of material usually require selective staining procedures prior to the measurement. Also electron beam damage is often encountered during TEM measurements especially if components such as poly(methacrylates) are present. In contrast, SFM measurements can be assumed not to significantly change the phase dimensions of the components.
Regenerating temperate forests under elevated CO2and nitrogen deposition: comparing biochemical and stomatal limitation of photosynthesis
Authors: Bauer G. A. , Berntson G. M. , Bazzaz F. A. 
Published: March 2003

SummaryPhotosynthesis of temperate trees growing in a competitive environment was investigated here in a factorial design of community composition (deciduous, coniferous and mixed species), carbon dioxide and nitrogen treatments. This study included seedlings of three deciduous (Betula alleghaniensis,Quercus rubra,Acer rubrum) and three coniferous (Pinus strobus,Picea rubens,Tsuga canadensis) species.Nitrogen partitioning changed significantly in response to the treatments. Higher area‐based nitrogen concentrations (Na) in the conifer needles, however, did not induce higher growth rates.Analysis of biochemical limitations of photosynthesis revealed that deciduous trees invested more nitrogen into carboxylation (Vcmax), electron transport (Jmax) and Piregeneration capacity, but at much lower absolute concentrations for Nathan conifers; consequently conifers maintained much higher rates for all three parameters. Deciduous species showed a strong stomatal limitation, whereas conifers maintained higher stomatal conductance at increasing mesophyll internal carbon dioxide concentration, indicating a much stronger assimilatory response to elevated carbon dioxide.Differences between the biochemical and stomatal response to elevated carbon dioxide and nitrogen indicate that within mixed stands, individual plant responses do not fully characterize community response.
Exploration of retinoid activity and the role of inflammation in acne: issues affecting future directions for acne therapy
Authors: Zouboulis CC 
Published: March 2003

AbstractThe review summarizes new results concerned with several important issues in the treatment of patients with acne. The first section reviews studies which show that 13‐cis retinoic acid, a molecule with strong biological activity but low binding affinity for retinoid receptors and cellular‐binding proteins in sebocytes, undergoes rapid intracellular conversion to all‐trans retinoic acid. This active metabolite exerts its actions on sebocyte gene expression by binding to the nuclear retinoic acid receptor rather than the retinoid X receptor. Importantly, 13‐cis retinoic acid, unlike all‐trans retinoic acid, does not induce cytochrome P450 1A1, an enzyme responsible for the metabolism of xenobiotics. Thus, administration of 13‐cis retinoic acid permits high long‐term intracellular accumulation of its active metabolite. The second section reviews studies which suggest that leukotriene B4 may play a key role in acne‐related inflammation. Results from a preliminary clinical study indicate that therapy with a specific lipoxygenase inhibitor is clinically effective in the treatment of patients with inflammatory acne and that its clinical efficacy is correlated with the drug’s ability to reduce total lipid levels, and especially pro‐inflammatory lipids, in sebum. Interestingly, 13‐cis retinoic acid has been shown to modulate the activities of LTB4 and inflammatory events in the development of acne. Therefore, future compounds targeting acne have to inhibit pro‐inflammatory lipids in sebum, and thus down‐regulate acne‐related inflammatory signals and reduce the LTB4‐induced migration of inflammatory cells.
Demographic and random amplified polymorphic DNA analyses reveal high levels of genetic diversity in a clonal violet
Authors: Auge Harald , Neuffer Barbara , Erlinghagen Friederike , Grupe Rudolf , Brandl Roland 
Published: March 2003

AbstractWe performed demographic and molecular investigations on woodland populations of the clonal herb Viola riviniana in central Germany. We investigated the pattern of seedling recruitment, the amount of genotypic (clonal) variation and the partitioning of genetic variation among and within populations. Our demographic study was carried out in six violet populations of different ages and habitat conditions. It revealed that repeated seedling recruitment takes place in all of these populations, and that clonal propagation is accompanied by high ramet mortality. Our molecular investigations were performed on a subset of three of these six violet populations. Random amplified polymorphic DNA analyses using six primers yielded 45 scorable bands that were used to identify multilocus genotypes, i.e. putative clones. Consistent with our demographic results and independent of population age, we found a large genotypic diversity with a mean proportion of distinguishable genotypes of 0.93 and a mean Simpson’s diversity index of 0.99. Using amova we found a strong genetic differentiation among these violet populations with a ΦST value of 0.41. We suggest that a high selfing rate, limited gene flow due to short seed dispersal distances and drift due to founder effects are responsible for this pattern. Although Viola riviniana is a clonal plant, traits associated with sexual reproduction rather than clonality per se are moulding the pattern of genetic variation in this species.
Comparative population structure and genetic diversity of Arceuthobium americanum (Viscaceae) and its Pinus host species: insight into host–parasite evolution in parasitic angiosperms
Authors: Jerome Cheryl A. , Ford Bruce A. 
Published: March 2003

AbstractIn a recent study we revealed that the parasitic angiosperm Arceuthobium americanum is comprised of three distinct genetic races, each associated with a different host in regions of allopatry. In order to assess the role of host identity and geographical isolation on race formation in A. americanum, we compared the genetic population structure of this parasite with that of its three principal hosts, Pinus banksiana, Pinus contorta var. latifolia and Pinus contorta var. murrayana. Despite the fact that A. americanum was divided into three genetic races, hosts were divided into only two genetic groups: (i) Pinus banksiana and hybrids, and (ii) P. contorta var. latifolia and var. murrayana. These findings suggest that factors such as geographical isolation and adaptation to different environmental conditions are important for race formation in the absence of host‐driven selection pressures. To assess factors impacting population structure at the fine‐scale, genetic and geographical distance matrices of host and parasite were compared within A. americanum races. The lack of a relationship between genetic and geographical distance matrices suggests that isolation‐by‐distance plays a negligible role at this level. The effect of geographical isolation may have been diminished because of the influence of factors such as random seed dispersal by animal vectors or adaptation to nongeographically patterned environmental conditions. Host–parasite interactions might also have impacted the fine‐scale structure of A. americanum because the parasite and host were found to have similar patterns of gene flow.
Plasma anti‐oxidant status and lipid profile in non‐gravida women with a history of pre‐eclampsia
Authors: Ozan Hakan , .Ilçöl Yes¸im , Kimya Yalçin , Cengiz Candan , Ediz Bülent 
Published: March 2003

Abstract
Objective:
To investigate the total plasma anti‐oxidant status, the plasma lipid profile and the uterine artery Doppler velocity waveform in formerly pre‐eclamptic women.
Methods:
Thirty‐two formerly pre‐eclamptic, non‐gravida women constituted the study group, while 28 age‐matched non‐gravida women who had never had pre‐eclampsia served as control subjects. On days 17–19 of their menstrual cycle, fasting plasma samples were collected for total anti‐oxidant status (TAS) and lipid profile evaluation, and uterine artery Doppler velocity waveform studies were performed. Results were analyzed with Mann–Whitney U‐test and Pearson correlation analysis.
Results:
There was no significant difference between the groups in means of the uterine artery Doppler velocity waveforms and the plasma lipid levels, but body mass index values were significant (P < 0.005). The TAS value was subnormal in 72% of the formerly pre‐eclamptic group and in 35% of the control group. The mean plasma TAS value was 1.20 ± 0.05 mmol/L and was significantly lower in the study group when compared with the control group (P < 0.05).
Conclusion:
The current study reveals significantly decreased TAS in women with a history of pre‐eclampsia, which may have an important role in pathophysiology.
Current status of prophylactic use of antimicrobial agents for cesarean section in Thailand
Authors: Liabsuetrakul Tippawan , Lumbiganon Pisake , Chongsuvivatwong Virasakdi , Boonsom Krongtip , Wannaro Prawit 
Published: March 2003

Abstract
Aims:
To evaluate actual practices and physician reasons for variation in prophylactic use of antimicrobial agents for cesarean section (CS).
Methods:
The study combined a survey of 2726 medical records and an interview of 50 practicing physicians at the obstetric departments of a university, a regional and a general hospital in Songkhla Province, Southern Thailand.
Results:
Practices that were consistent with systematic reviews were use in 94%, prescription after cord clamping in 86%, and choosing ampicillin in 91%, because physicians believed in the advantages of these practices. Indications for prophylactic use ranged from routine use for all cases to selective use for indicated cases such as ruptured membranes, vaginal examinations, labor, maternal obesity, or unplanned CS. Single‐dose practice was varied greatly across hospitals, from 9% to 84%. The reasons given by physicians for a multiple‐dose regimen were personal experience in this regimen and belief in its superiority under their local conditions. This practice was less common where the hospital had practice recommendations.
Conclusions:
Not all evidence‐based knowledge is adopted in practice. The prophylactic use of antimicrobial agents for CS varies among physicians. Past experience and personal beliefs in the limitation of research generalizability are the barriers to such adoption.
Minimal stimulation protocol for use with intrauterine insemination in the treatment of infertility
Authors: Dhaliwal Lakhbir K. , Sialy Ravinder K. , Gopalan Sarala , Majumdar S. 
Published: March 2003

AbstractObjective: To determine whether minimal stimulation with clomiphene and one injection of 150 IU of human menopausal gonadotrophin (hMG) provides pregnancy rates comparable with those in a conventional full hMG stimulation protocol for infertile patients undergoing intrauterine insemination (IUI).Methods: A prospective study was carried out at the Infertility Clinic of a teaching institute and tertiary care referral center in Chandigarh, India. Two hundred couples with either unexplained infertility or ovulatory dysfunction cases who ovulated with clomiphene citrate (CC) but failed to conceive were offered ovarian stimulation with CC and hMG along with IUI for 420 cycles. Pregnancy rate, medication and monitoring cost were compared between minimal and conventional stimulation protocols.Results: There was no difference in the couples of the two stimulation protocols regarding their age, duration and type of infertility as well as cause of infertility. Number of ampoules of hMG and monitoring costs were significantly higher in the full hMG stimulation cases whereas pregnancy rate was comparable in both protocols.Conclusion: Minimal stimulation appears to be an effective protocol in cases of unexplained infertility undergoing intrauterine insemination. Reduced cost and minimal monitoring is appealing to patients and the clinician.
Cerebral blood flow distribution and hypoxic–ischemic brain damage in newborn rats
Authors: Xia Yi Xin , Sameshima Hiroshi , Ikeda Tomoaki , Higo Takafumi , Ikenoue Tsuyomu 
Published: March 2003

AbstractObjective: Our purpose was to assess the cerebral blood flow distribution and resulting grade of hypoxic–ischemic brain damage in newborn rats.Methods: Seven‐day‐old Wistar rats (n = 75) underwent left common carotid artery ligation followed by 2 hours hypoxia (8% oxygen in nitrogen) at 33°C. The control animals were exposed to hypoxia without ligation (n = 8). Colored microspheres of 15 µm in diameter were administered into the left cardiac ventricle percutaneously at the end of hypoxia. They were killed 24 hours after induced injury. Brain sections 2 mm in thickness were removed for microtubule‐associated protein 2 (MAP‐2) staining, and remaining parts were separated into left and right hemispheres for counting the microspheres. The blood flow distribution to the ligated side was expressed as the difference from the non‐ligated control side. Severity of MAP‐2 disappearance was ranked as normal, mild or severe.Results: In the control rats, there was no loss of MAP‐2 staining. The blood flow equally distributed into both cerebral hemispheres. The cerebral blood flow distribution on the side of carotid artery ligation decreased by 44.7 ± 21.9% in the mildly damaged group and 65.8 ± 16.8% in the severely damaged group.Conclusion: The greater the percentage difference of blood flow distribution from the non‐ligated side, the more severe the brain damage.
The Retrospective Study of Second‐line Chemotherapy in Ovarian Cancer
Authors: Nishii Hiroshi , Yasuda Makoto , Wachi Toshiki , Kimura Eizo , Ochiai Kazuhiko , Ochiai Kazunori , Tanaka Tadao 
Published: March 2003

Objective:  To evaluate the efficacy of Second‐line Chemotherapy for ovarian cancer not from short term efficacy but from the survival rate.Patients and Methods:  Eighty‐seven patients with epitherial ovarian cancer treated with Second‐line chemotherapy from 1993 were examined retrospectively. All the patients were treated with platinum as first line chemotherapy (≥ 3 courses). Paclitaxel was used for Second‐line Chemotherapy in 25 patients. The Kaplan‐Meier Method and Log‐Rank Test were carried out for the cumulative survival rate and analysis.Results:  The Median Survival Time of all patients after Second‐line Chemotherapy was 23.6 months. Any significant difference in the survival rate was recognized only by the histological diagnosis (p < 0.0001). There was no significant difference in the survival rates whether patients were treated with paclitaxel as second line chemotherapy or not (p = 0.1915). The disease free survival period of the Second Look Laparotomy (SLL) negative group (23.9 months) is longer than that of SLL positive group (6.2 months).Conclusions:  The survival rate after Second‐line Chemotherapy was influenced only by histological diagnosis. ACTA OBST GYNAEC JPN Vol. 54, No. 9, pp. 1429–1436, 2002
Use of an isocitrate lyase promoter–GFP fusion to monitor carbon metabolism of the plant pathogen Tapesia yallundae during infection of wheat
Authors: Bowyer Paul , Mueller Elisabeth , Lucas John 
Published: March 2003

AbstractGreen fluorescent protein (GFP) has been used as a vital marker in a variety of species. Here, we present the use of a GFP–promoter fusion to visualize carbon metabolism in a pathogenic fungus during growth on defined medium and during infection of plants. Isocitrate lyase (ICL), a key enzyme in carbon metabolism, is tightly regulated at the transcriptional level, with high levels of expression during 2‐carbon growth and no expression during growth on glucose. A GFP–ICL promoter fusion was used to visualize carbon metabolism in the plant pathogenic fungus Tapesia yallundae during growth in vitro and in the host plant. The ICL promoter from Neurospora crassa retained its native induction and repression characteristics in T. yallundae. Loss of GFP fluorescence from hyphae after repression of the ICL promoter suggested a rapid turnover rate for GFP in T. yallundae. Regulation of this promoter was observed during infection, with expression occurring only on the plant surface, suggesting that 2‐carbon metabolism occurs during this phase. These data suggest that GFP is a useful vital marker for the in planta imaging of fungal metabolism.
Applications of the microbiopsy technique in non‐cervical cytology: where cytology and histology meet
Authors: Mravunac M , Verbeek D , Van Heusden C , Reuterink A , Hop G , Smedts F 
Published: March 2003

AimTo evaluate a recently developed technique allowing the removal and processing for histology of thick tissue fragments, called microbiopsies, from non‐cervical cytology specimens.Methods and resultsForty‐five non‐cervical smears from malignant tumours which contained microbiopsies were selected and processed. Sufficient sections could be cut in most cases for haematoxylin and eosin and an extensive panel of immunostaining. Seventy‐one per cent of histological slides from the microbiopsies were representative of the tumour and confirmed the diagnosis. In 29% of the cases they were too small, contained non‐representative tissue or showed extensive necrosis. Surprisingly, immunostaining results were at least the same and often better than those observed in routine formalin‐fixed, paraffin‐embedded tissue. Immunostaining profiles allowed distinction of tumour subtypes. Antigen retrieval techniques could be avoided in all cases.ConclusionsApplication of the microbiopsy technique in routine cytology smears containing microbiopsies is helpful, particularly in those cases in which the diagnosis is not clear on the basis of the cytology smear and in cases in which there are not enough cytology slides for immunohistochemical examination.
Origin of primary gastric T‐cell lymphomas from intraepithelial T‐lymphocytes: report of two cases
Authors: Foss  , Schmitt‐Gräff  , Daum  , Anagnostopoulos  , Assaf  , Hummel  , Stein  
Published: March 2003

AimsThe classification of primary gastric T‐cell lymphomas is uncertain due to the exceeding rarity of these tumours; many of the reported cases were felt to be similar to node‐based lymphomas. We describe two cases of primary gastric T‐cell lymphoma with evidence of origination from intraepithelial T‐lymphocytes.Methods and resultsBoth tumours were restricted to the stomach; one displaying a large ulcerated mass, the other a widespread superficial tumour manifestation. Histologically the first tumour was composed of sheets of medium‐sized lymphoid cells showing marked epitheliotropism at the edge of the ulcer, and a CD3+ , CD4−, CD8−, CD20−, CD56−, CD103+ , βF1+ phenotype. The second case differed histologically and immunophenotypically from the first case. In addition to lamina propria and submucosal infiltration, the lymphoma contained an extensive intraepithelial component even in large areas without other evidence of tumour. The neoplastic cells ranged in size from small to medium and large. Immunohistology disclosed a CD3+, CD4+, CD8−, CD20−, CD56−, βF1+ phenotype. Staining for CD103 could not be performed in this case since frozen material was not available.ConclusionsThe prominent epitheliotropism, the marked intraepithelial growth and the expression of CD103 strongly imply a derivation of these primary gastric lymphomas from intraepithelial T‐lymphocytes. Additional studies of larger series will clarify whether the findings described here are typical of primary gastric T‐cell lymphomas.