bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of invertebrate biodiversity across a natural edge
Authors: DANGERFIELD J. MARK , PIK ANTHONY J. , BRITTON DAVID , HOLMES ANDREW , GILLINGS MICHAEL , OLIVER IAN , BRISCOE DAVID , BEATTIE ANDREW J. 
Published: July 2003

Abstract Most ecologists are comfortable with the notion of habitats as recognizable entities and also with situations where the junction between two adjacent habitats forms a discrete edge. Such edges form naturally because of sharp changes in important edaphic, geomorphological, climatic or chemical properties to which plants, in particular, respond. Less clear is the effect of such edges on assemblages of mobile organisms, especially invertebrates that operate at relatively small spatial scales. The objective of the present study was to sample invertebrate composition across a natural edge between a well‐developed riparian habitat on fluvial sands and a saltbush habitat developed on a stony gibber plain in a semi‐arid region of New South Wales, Australia. A total of 150 pitfall traps on five 1‐km‐long transects that straddled the edge produced more than 13 000 adult specimens from 21 ordinal invertebrate taxa. A total of 10 446 beetle, ant, wasp, fly and springtail specimens were further sorted into 426 morphospecies. Comparisons and estimates of trends in abundance and richness were made, along with computation of multivariate dissimilarity and permutation statistics, to determine if the land system edge was coincident with changes in invertebrate abundance and composition. These analyses were unable to detect disjunctions in diversity coincident with the edge. The data suggest that many taxa are either present consistently in both habitats or are mostly found in one habitat but ‘leak’ several hundred metres across into the other. Few taxa were unique to either habitat. The result is that assemblage composition for invertebrates changes gradually over distances of up to 400 m either side of the edge and that the distance to a recognizable change in composition is taxon dependent. Even sharp habitat edges, as defined by discrete changes in soils and plants, are not edges but broad transition zones for many invertebrate taxa. There are several implications of these results, especially for landscape ecology.
Myths and facts on ratadas: Bamboo blooms, rainfall peaks and rodent outbreaks in South America
Authors: JAKSIC FABIAN M. , LIMA MAURICIO 
Published: July 2003

Abstract ‘Ratadas’ are rodent irruptions or outbreaks that have been recorded in South America since the Spanish conquest in the 16th century. The notion that ratadas are associated with bamboo flowering and subsequent mast seeding at cycles of 30 years has appeared in the literature since the late 1800s. Based on 63 well‐documented cases, we show that not only are ratadas associated with bamboo blooming, but also many are associated with rainfall peaks, and that these two outbreak types are geographically interspersed over South America. In addition, we dispel the notion that South American bamboo blooms occur every 30 years, which may only be the case forMerostachys fistulosa. For other species the modal cycles occur every 14 (Merostachysspp.), 12 (Chusquea quilaand/orvaldiviensis) or 14 years (Chusquea coleou). We also propose the hypothesis that rainfall‐associated ratadas are ultimately caused by the occurrence of El Niño, and discuss the possible population dynamic mechanisms underlying rodent outbreaks in South America. Aiming at setting a standardized framework for spatial and temporal comparisons, we propose a trapping protocol and a threshold density for assigning the ‘ratada’ label. Several of the mice implicated in ratadas are reservoirs of emerging diseases, thus emphasizing the need for predictive power to forecast disease epidemics that affect human populations. Further, ratadas may be viewed as pulsed resources, thus enabling us to learn more of the ways communities respond to such intermittent inputs.
Tree heterogeneity, resource availability, and larger scale processes regulating arboreal ant species richness
Authors: RIBAS CARLA R. , SCHOEREDER JOSÉ H. , PIC MIREILLE , SOARES SANDRA M. 
Published: July 2003

Abstract Processes acting on different spatial and temporal scales may influence local species richness. Ant communities are usually described as interactive and therefore determined by local processes. In this paper we tested two hypotheses linked to the question of why there is local variation in arboreal ant species richness in the Brazilian savanna (‘cerrado’). The hypotheses are: (i) there is a positive relationship between ant species richness and tree species richness, used as a surrogate of heterogeneity; and (ii) there is a positive relationship between ant species richness and tree density, used as a surrogate of resource availability. Arboreal ants were sampled in two cerrado sites in Brazil using baited pitfall traps and manual sampling, in quadrats of 20 m × 50 m. Ant species richness in each quadrat was used as the response variable in regression tests, using tree species richness and tree density as explanatory variables. Ant species richness responded positively to tree species richness and density. Sampling site also influenced ant species richness, and the relationship between tree density and tree species richness was also positive and significant. Tree species richness may have influenced ant species richness through three processes: (i) increasing the variety of resources and allowing the existence of a higher number of specialist species; (ii) increasing the amount of resources to generalist species; and (iii) some other unmeasured factor may have influenced both ant and tree species richness. Tree density may also have influenced ant species richness through three processes: (i) increasing the amount of resources and allowing a higher ant species richness; (ii) changing habitat conditions and dominance hierarchies in ant communities; and (iii) increasing the area and causing a species–area pattern. Processes acting on larger scales, such as disturbance, altitude and evolutionary histories, as well as sampling effect may have caused the difference between sites.
Comparison of a common and rare species of Mimosa (Mimosaceae) in Central Brazil
Authors: SIMON MARCELO FRAGOMENI , DU VALL HAY JOHN 
Published: July 2003

Abstract  The aim of this study was to verify differences in the biology of a common widespread species (Mimosa claussenii Benth.) and three rare endemics (Mimosa decorticans Barneby, M. heringeri Barneby, and M. setosissima Taub.). We studied three populations of M. claussenii and one population of each rare species at four localities in central Brazil. We compared the population structure, phenology, fruit set, seed predation, germination, establishment and root/shoot ratio in these six populations. The endemic species occurred in higher densities and smaller individuals were more abundant. When in sympatry, the rare and common species showed a significant negative correlation of density. Mimosa claussenii occurred in drier and rocky environments, whereas M. decorticans and M. setosissima occurred in moister habitats. Rare species had higher levels of fruit set, more viable seeds per individual, and heavier seeds. Mimosa setosissima had the highest level of germination and establishment rate, but did not survive away from its endemism centre. The common species had a higher root/shoot ratio. Overall, the biological aspects studied indicated an advantage in reproductive biology for the rare in relation to the common species. The small geographical range of the rare species may be related to edaphic isolation and climatic changes in the Quaternary.
Effect of fire regime on plant abundance in a tropical eucalypt savanna of north‐eastern Australia
Authors: WILLIAMS PAUL R. , CONGDON ROBERT A. , GRICE ANTHONY C. , CLARKE PETER J. 
Published: July 2003

Abstract  Changes in plant abundance within a eucalypt savanna of north‐eastern Australia were studied using a manipulative fire experiment. Three fire regimes were compared between 1997 and 2001: (i) control, savanna burnt in the mid‐dry season (July) 1997 only; (ii) early burnt, savanna burnt in the mid‐dry season 1997 and early dry season (May) 1999; and (iii) late burnt, savanna burnt in the mid‐dry season 1997 and late dry season (October) 1999. Five annual surveys of permanent plots detected stability in the abundance of most species, irrespective of fire regime. However, a significant increase in the abundance of several subshrubs, ephemeral and twining perennial forbs, and grasses occurred in the first year after fire, particularly after late dry season fires. The abundance of these species declined toward prefire levels in the second year after fire. The dominant grass Heteropogon triticeus significantly declined in abundance with fire intervals of 4 years. The density of trees (>2 m tall) significantly increased in the absence of fire for 4 years, because of the growth of saplings; and the basal area of the dominant tree Corymbia clarksoniana significantly increased over the 5‐year study, irrespective of fire regime. Conservation management of these savannas will need to balance the role of regular fires in maintaining the diversity of herbaceous species with the requirement of fire intervals of at least 4‐years for allowing the growth of saplings >2 m in height. Whereas late dry season fires may cause some tree mortality, the use of occasional late fires may help maintain sustainable populations of many grasses and forbs.
Extended gestation with late‐autumn births in a cool‐climate viviparous gecko from southern New Zealand (Reptilia: Naultinus gemmeus)
Authors: WILSON JACKIE L. , CREE ALISON 
Published: July 2003

Abstract  Female viviparous lizards from temperate locations in the Southern Hemisphere (New Zealand, Tasmania (Australia), South Africa and South America) often have reproductive activity spanning many months of the year. In contrast, vitellogenesis and pregnancy are often confined to the spring/summer months in viviparous species from temperate zones of the Northern Hemisphere. An extreme Southern Hemisphere example is the nocturnal common gecko from New Zealand, Hoplodactylus maculatus (Gray 1845), in which females exhibit biennial reproduction with pregnancy lasting up to 14 months in a cool‐climate population. Here, we examined whether such an extended reproductive cycle also occurs in a diurnal species, the jewelled gecko Naultinus gemmeus (McCann 1955), at a similar latitude. Palpation was used to assess reproductive condition non‐invasively. In contrast to the nearby higher‐altitude population of H. maculatus, N. gemmeus reproduces annually. Vitellogenesis occurs from autumn to spring in both species, but pregnancy ends after about 7 months in N. gemmeus. Birth occurs in the seemingly unpropitious season of mid‐ to late autumn, a pattern that may be unique for lizards from cool‐temperate zones. We hypothesize that there are major differences between populations of N. gemmeus and H. maculatus with respect to survival of autumn‐born neonates and/or costs to females from remaining pregnant over winter. Museum specimens of N. gemmeus support anatomical inferences from palpation; they also suggest that vitellogenesis may begin before the end of pregnancy (which may be essential to completing each reproductive cycle within a year) and that some populations may show gestation in utero over winter, as in H. maculatus. Extended gestation appears to be a common response to cool climates for Southern Hemisphere lizards that have independently evolved viviparity.
Evaluating the role of imaging methods in the diagnosis of chronic pancreatitis
Authors: GUO Tao , QIAN Jia Ming , YANG Ai Ming , LI Jing Nan , LU Xing Hua 
Published: July 2003

OBJECTIVE:  To evaluate the role of imaging methods in the diagnosis of chronic pancreatitis (CP) in improving the accuracy of a clinical diagnosis of CP.METHODS:  The results of the imaging methods used for 129 cases diagnosed as CP in Peking Union Medical College Hospital from 1991 to 2000 were retrospectively analyzed. The imaging methods included ultrasonography (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasonography (EUS).RESULTS:  The sensitivity of EUS and MRCP was high and was in good agreement with ERCP in the diagnosis of CP. The sensitivity of ERCP was superior to US and CT (P < 0.05). The sensitivity of US and CT for diagnosing dilation of the pancreatic duct was 59.4% and 60%, respectively, the specificity was 93.8% and 95.7%, respectively. BT‐PABA had a better correlation with ERCP in the group with severe changes of the pancreatic duct than in the mild or moderate group. The more complications of CP that were present, the more severe the lesions of the pancreatic duct.CONCLUSION:  Among the traditional imaging modalities for diagnosing CP, ERCP is the most sensitive. MRCP and EUS, the promising and novel examination techniques, have high sensitivity and good agreement with ERCP.
Gastric mucosa‐associated lymphoid tissue lymphoma and Helicobacter pylori infection
Authors: Sheng Jian Qiu , Li Shi Rong , Wang Lu Ping , Gao Lan Xiang , Zhao Xiao Jun , Tian Yu Wang , Deng Yong Jiang 
Published: July 2003

OBJECTIVE:  Numerous studies have demonstrated the role of Helicobacter pylori infection in the pathogenesis of gastric MALT lymphoma and the present study aimed to analyze this correlation in Chinese patients.METHODS:  Thirty‐five cases of primary gastrointestinal non‐Hodgkin's lymphoma that had been surgically resected and pathologically examined during the past 20 years were collected. The tissue samples were re‐examined by a physician from the pathology department. Immunohistochemical staining and H. pylori tests were conducted. The clinical diagnosis of gastric MALT lymphoma and the results of therapy were analyzed.RESULTS:  According to the immunohistochemistry results, 21 cases were MALT lymphoma, and of these 16 were gastric MALT lymphoma, one was intestinal MALT lymphoma and four were colonic MALT lymphoma. Of the 16 samples of gastric MALT lymphoma, 13 were positive for H. pylori infection and three could not be evaluated because the sample was full of cancer cells. Of the cases of gastric MALT lymphoma, two were stage I1, five were stage II1, and nine were stage IIE. Eleven patients underwent endoscopy: three were misinterpreted as gastric carcinoma, one was diagnosed as Menetrier's disease, one as chronic atrophic gastritis, and only six cases were correctly diagnosed before surgery. Eradication of H. pylori in one patient with gastric MALT lymphoma resulted in regression of the lesion; that patient was followed up for 3 years without relapse. Fifteen cases underwent surgery and 10 were followed up for 5 years: four relapsed within 1−2 years after operation and six remained well.CONCLUSION:  There is a close relationship between H. pylori infection and gastric MALT lymphoma. Early gastric MALT lymphoma can be cured after eradication of H. pylori. The depth of the lesion should be diagnosed by echoendoscopy and therapy should be chosen on the basis of the stage of the disease.
Experimental study of the safety of the selective COX‐2 inhibitor, celecoxib, for gastric mucosa
Authors: LI Jun Ting , LI Zhao Shen , ZHAN Xian Bao , CUI Zhong Min , NIE Shi Nan 
Published: July 2003

OBJECTIVE:  To compare the gastric mucosal damage induced by a COX‐2 inhibitor, celecoxib, and a conventional NSAID, indomethacin.METHODS:  A rat model of NSAID‐induced gastric mucosal damage was prepared for indomethacin and celecoxib separately (n = 8). After gastric damage was induced by 100% ethanol, celecoxib was administered by gastric gavage (n = 8). Gastric mucosal concentrations of 6‐keto‐PGF1α and TXB2 and the lesion index (LI) were measured. Morphological changes of the gastric mucosa were assessed under light and scanning electron microscopy.RESULTS:  Indomethacin caused marked gastric damage (LI: 13.38 ± 2.06) and significant reduction of the concentrations of 6‐keto‐PGF1α and TXB2 (P < 0.01), Celecoxib did not produce necrotic injuries on healthy gastric mucosa (LI: 0), but the mucosal injuries previously induced by ethanol worsened after its administration (LI: 37.19 ± 3.34 vs 19.90 ± 2.28, P < 0.01).CONCLUSIONS:  Inhibition of COX‐1 is the major mechanism of NSAIDs in producing gastric mucosal damage. As a selective COX‐2 inhibitor, celecoxib does not produce toxic injuries of the healthy gastric mucosa, and is thus safer than conventional NSAID. However, when administered in the presence of an altered gastric mucosa, gastric injuries were worsened.
Effect of SU5416 on the inhibition of growth and metastasis of human gastric cancer implanted in nude mice
Authors: ZHANG Guo Feng , WANG Yuan He , WANG Qiang , ZHANG Min Gao , HAN Ce Ran , Yang RAO Ying 
Published: July 2003

OBJECTIVE:  To study the effects of the angio­genesis inhibitor SU5416 on the growth and liver metastasis of gastric cancer and to investigate its effects on the apoptosis of gastric cancer cells.METHODS:  A model simulating the metastasis of human gastric cancer was established by orthotopic implantation of histologically intact human tumor tissue into the gastric wall of nude mice, which were randomly divided into four groups: control group (saline solution), 5‐FU group (fluorouracil 30 mg/kg per day i.p), SU5416 group (SU5416 15 mg/kg per day i.p.), and combined treatment with 5‐Fu and SU5416. Eight weeks after implantation, the tumor weight, inhibition rate, intratumoral microvessel density (MVD), apoptotic index (AI), and the status of metastasis were evaluated after the mice were killed.RESULTS:  Compared with the control group, the growth of the orthotopically‐implanted tumors was significantly inhibited, with reduced weight, and the tumor inhibition rate was 44.5%, 79.3%, and 84.4%, respectively, in the mice treated with 5‐FU, SU5416 and both. The incidence of liver metastasis was also significantly decreased in the 5‐Fu, SU5416, and combination groups compared with the control group (36.4%, 25.0%, and 0% vs 90.0%). The MVD of the 5‐FU group, the SU5416 group and the combined group was 13.1 ± 4.7, 3.9 ± 1.8 and 2.1 ± 1.5, respectively, which was decreased significantly compared with the control group (14.6 ± 5.8). The AI was increased significantly in the treated mice (6.81 ± 4.92%, 9.82 ± 3.76% and 17.65 ± 9.85% vs 3.76 ± 2.25%). The growth of and liver metastasis of the human gastric cancer implanted in the nude mice were both more significantly inhibited in the SU5416 group and the combined group than in the control and 5‐FU groups (P < 0.05).CONCLUSIONS:  SU5416 can induce apoptosis in gastric cancer by inhibiting tumor angiogenesis and has a strong inhibitory effect on both the growth and liver metastasis of gastric cancer implanted in nude mice. The combination of SU5416 with other cytotoxic agents is more effective.
Clinical and endoscopic features of ischemic colitis
Authors: YANG Xue Song , LU Yu Min , YU Chang Fu , WANG Chang Wu 
Published: July 2003

OBJECTIVE:  To review the clinical and endoscopic features, and outcome of ischemic colitis.METHODS:  Sixty cases with the diagnosis of ischemic colitis were retrospectively analyzed. All the patients were under observation in hospital and most of them underwent colonoscopy at least twice: once for diagnosis and then follow‐up after treatment. The demographic data, presenting symptoms, endoscopic findings, laboratory tests, and treatment were reviewed.RESULTS:  Fifty‐two of the 60 cases were over 50 years old (87%; mean age, 59.9 years): 40 female, 20 male (2 : 1); 76.0% of these patients had a coexistent disease such as a cardio‐cerebrovascular disorder, diabetes, hematologic diseases or a previous history of abdominal surgery. Abdominal pain (57/60, 95%), hematochezia (55/60, 91.7%), and diarrhea (26/60, 43.3%) were the main complaints. Lesions seen on colonoscopy were more commonly located in the left colon (46/60, 79.3%) and rectum (5/60, 8.6%), and were characteristically segment‐distributed, including hemorrhagic edematous mucosa, erosions, ulcerations, pseudopolyps, and stricture. Ultrasonography revealed colonic wall thickening in 13 cases (13/55, 21.7%), and small to moderate ascites was detected in 4 cases (4/55, 7.3%). In this cohort, most of the patients recovered (49/60, 81.7%) or improved (10/60, 16.7%) after conservative treatment. Only one patient who had a myocardial infarction prior to the onset of the ischemic colitis, died from peritonitis complicated with septic shock. Progress and outcome were associated with the patient's age, severity of the lesions, clinical course, underlying diseases and the complications.CONCLUSION:  Colonoscopy is safe and helpful in the early diagnosis of ischemic colitis. Nongangrenous colonic ischemia usually requires only medical management and is associated with a good prognosis.
Clinical application of wireless capsule endoscopy
Authors: GE Zhi Zheng , HU Yun Biao , GAO Yun Jie , XIAO Shu Dong 
Published: July 2003

BACKGROUND:  Diagnostic modalities for identifying lesions within the small bowel have been quite limited. Wireless capsule endoscopy (WCE) is a new, innovative technique that can detect very small mucosal lesions in the entire small bowel and can be used in the outpatient setting. The present study explored the diagnostic value, tolerance and safety of WCE in the identification of small bowel pathology that was not detected with conventional small bowel imaging studies.METHODS:  From May through September 2002, 15 patients with suspected small bowel diseases were prospectively examined, Of them, 12 presented with persistent obscure gastrointestinal bleeding and negative findings on upper endoscopy, colonoscopy, small bowel radiography, and bleeding‐scan scintig‐raphy or mesenteric angiography.RESULTS:  Wireless capsule endoscopy identified pathologic small bowel findings in 11 of the 15 patients (73%): angioectasias, Dieulafoy's lesion, polypoid lesion, submucosal mass, Crohn's disease, carcinoid tumor, lipoma, aphthous ulcer, and hemorrhagic gastritis; four of the patients had two lesions. The images displayed were considered to be good. The capsule endoscopes remained in the stomach for an average of 82 min (range 6−311 min) and the mean transit time in the small bowel was 248 min (range 104−396 min). The mean time of recording was 7 h 29 min (from 5 h to 8 h 30 min). The mean time to reach the cecum was 336 min (180−470 min). The average number of the images transmitted by the capsule was 57 919 and the average time the physician took to review the images transmitted by the capsule was 82 min (range 30−120 min). The average time of elimination of the capsule was 33 h (range 24−48 h). All 15 patients reported that the capsule was easy to swallow, painless, and preferable to conventional endoscopy. No complications were observed.CONCLUSIONS:  Wireless capsule endoscopy is safe, well tolerated, and useful for identifying occult lesions of the small bowel, especially in patients who present with obscure gastrointestinal bleeding.