bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal breast‐milk and intestinal bifidobacteria guide the compositional development of the Bifidobacterium microbiota in infants at risk of allergic disease
Authors: Grönlund M.‐M. , Gueimonde M. , Laitinen K. , Kociubinski G. , Grönroos T. , Salminen S. , Isolauri E.
Published: October 2007

Background
The sources and the impact of maternal bacteria on the initial inoculum of the intestinal microflora of newborn infants remain elusive.

Objective
To assess the association between maternal breast‐milk and fecal bifidobacteria and infants' fecal bifidobacteria.

Methods
Sixty‐one mother–infant pairs were included, special emphasis being placed on the maternal allergic status. Bifidobacteria were analysed by a direct PCR method in fecal samples from mothers at 30–35 weeks of gestation and from infants at 1 month of age and from breast‐milk samples 1 month post‐partum.

Results
Fecal Bifidobacterium adolescentis and Bifidobacterium bifidum colonization frequencies and counts among mother–infant pairs correlated significantly (P=0.005 and 0.02 for frequencies, respectively, and P=0.002 and 0.01 for counts, respectively). Only infants of allergic, atopic mothers were colonized with B. adolescentis. Each of the breast‐milk samples contained bifidobacteria [median 1.4 × 103 bacterial cells/mL; interquartile range (IQR) 48.7–3.8 × 103]. Bifidobacterium longum was the most frequently detected species in breast‐milk. Allergic mothers had significantly lower amounts of bifidobacteria in breast‐milk compared with non‐allergic mothers [median 1.3 × 103 bacterial cells/mL (IQR 22.4–3.0 × 103) vs. 5.6 × 103 bacterial cells/mL (1.8 × 103–1.8 × 104), respectively, (P=0.004)], and their infants had concurrently lower counts of bifidobacteria in feces [3.9 × 108 bacterial cells/g (IQR 6.5 × 106–1.5 × 109) in infants of allergic mothers, vs. 2.5 × 109 bacterial cells/g (6.5 × 108–3.2 × 1010) in infants of non‐allergic mothers, P=0.013].

Conclusions
Breast‐milk contains significant numbers of bifidobacteria and the maternal allergic status further deranges the counts of bifidobacteria in breast‐milk. Maternal fecal and breast‐milk bifidobacterial counts impacted on the infants' fecal Bifidobacterium levels. Breast‐milk bacteria should thus be considered an important source of bacteria in the establishment of infantile intestinal microbiota.
Can hypertonic saline inhalation influence preformed chemokine and mediator release in induced sputum of chronic obstructive pulmonary disease patients? Comparison with isotonic saline
Authors: Cianchetti S. , Bacci E. , Bartoli M. L. , Ruocco L. , Pavia T. , Dente F. L. , Di Franco A. , Vagaggini B. , Paggiaro P.
Published: October 2007

Background
Hypertonic saline (HS) has been shown to modulate in vitro cell functions according to the state of cell activation; however, few studies have evaluated the effect of HS in vivo. Chronic airway inflammation, a major feature of chronic obstructive pulmonary disease (COPD), is associated with an activation of inflammatory and resident cells, which in turn makes them more prompt to respond to further stimuli.

Objective
To evaluate whether HS might modulate, also in vivo, the release of preformed mediators and intracellular chemokines from airway cells of COPD patients.

Methods
Sputum was induced by inhalation of either HS (4.5% w/v) or isotonic saline (IS 0.9% w/v) solution and processed by plug selection. We measured eosinophil cationic protein (ECP), neutrophil elastase (NE), IL‐8 and monocyte chemoattractant protein‐1 (MCP‐1) in sputum samples obtained by either HS or IS inhalation in 24 COPD patients.

Results
No significant difference in mediators measured in sputum samples obtained by the two different inductions was observed; also, there was no significant difference in sputum sample volumes, cell viability, total and differential cell counts. Repeatability between the two tests was high for ECP, NE, macrophages, neutrophils and eosinophils, and satisfactory for IL‐8 and MCP‐1.

Conclusions
Hyperosmolarity does not affect the levels of the inflammatory mediators and chemokines examined or the cell counts measured in induced sputum obtained from COPD patients. This study does not support the hypothesis that HS can stimulate chemokine and mediator release from airway cells of COPD patients. Therefore, HS and IS can be interchangeably used to measure inflammatory mediators in the sputum supernatant of COPD patients.
Serum retinol‐binding protein 4 levels are elevated in non‐alcoholic fatty liver disease
Authors: Seo J. A. , Kim N. H. , Park S. Y. , Kim H. Y. , Ryu O. H. , Lee K. W. , Lee J. , Kim D. L. , Choi K. M. , Baik S. H. , Choi D. S. , Kim S. G.
Published: October 2007

Objective  Retinol‐binding protein 4 (RBP4) is a recently identified adipokine that is elevated in the serum in several insulin‐resistant states. We investigated the relationship between non‐alcoholic fatty liver disease (NAFLD) and serum RBP4 in nondiabetic adults.

Methods  One hundred and fifty‐nine nondiabetic, non‐alcoholic subjects (95 males and 64 females) participated in this study. Division of subjects into a NAFLD group (n = 73; 45 males and 28 females) or a normal group (n = 86; 50 males and 36 females) was based on the presence of fatty liver disease determined by sonography.

Results  Serum RBP4 levels in the NAFLD group were significantly higher than those in the normal group (62·8 ± 16·0 mg/l vs. 51·7 ± 14·6 mg/l, P < 0·0001). Multiple logistic regression analysis revealed that the RBP4 level was an independent factor associated with NAFLD (P = 0·0042). In addition, serum RBP4 levels were positively correlated with serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ‐glutamyltranspeptidase (GGT) levels. The significant association between serum RBP4 and GGT levels remained even after adjusting for age, gender, body mass index, the homeostasis model of assessment (HOMA) value and the presence of NAFLD (r = 0·3097, P = 0·0002).

Conclusion  Serum RBP4 levels are significantly associated with NAFLD and liver enzymes.
What is the best method of detecting endometrial cancer in outpatients?‐endometrial sampling, suction curettage, endometrial cytology
Authors: Kondo E. , Tabata T. , Koduka Y. , Nishiura K. , Tanida K. , Okugawa T. , Sagawa N.
Published: October 2007

Objective:  Office methods of endometrial sampling for outpatients with abnormal uterine bleeding should be minimally invasive. The purpose of this study was to determine the best method for detecting endometrial cancer in an outpatients setting.

Methods:  In all, 114 symptomatic women who were suspected of having endometrial disease by their local gynaecologist were enrolled in this study. After pelvic examination and transvaginal ultrasonography, endometrial cytology, suction endometrial curettage, and four‐site endometrial biopsy were performed, in this order without anaesthesia in each patient. After endometrial sampling, the patient was asked to comment on the intensity of any pain experienced during each procedure. Then the final histological diagnosis made from the surgical materials was compared with the results of the three pre‐operative methods.

Results:  Among the 114 consecutive patients, 56 had endometrial carcinoma, three had carcinosarcoma, six had endometrial hyperplasia, and 49 had benign conditions. The sensitivity of detecting malignancy was 88% (52/59) with endometrial cytology, 92% (54/59) with suction curettage, and 88% (52/59) with four‐site biopsy. When endometrial cytology was combined with suction curettage, the sensitivity of detecting malignancy was increased from 92% to 98%, whereas the sensitivity was increased from 88% to 97%, when endometrial cytology was added to four‐site biopsy. Suction curettage was significantly less painful than four‐site biopsy.

Conclusion:  Our data indicated that suction curettage plus endometrial cytology was the best combination for pathological examination of outpatients with abnormal uterine bleeding.
Characteristic cytological features of histological grade one (G1) breast carcinomas in fine needle aspirates
Authors: Sauer T. , Karimzadeh M.
Published: October 2007

Objective:  To analyse the spectrum of nuclear features as well as dissociation pattern found in fine needle aspirates (FNAC) from histological grade 1 breast carcinomas and evaluate the critical cytological features of these lesions.

Material and methods:  The material consisted of FNAC smears from 494 histologically confirmed grade 1 breast carcinomas. All smears were revaluated for cell dissociation pattern, nuclear size, cell uniformity, nucleoli, nuclear margin and chromatin pattern. All features were compared with the histological subtype and cytological grading.

Results:  73.9% of the cases were cytological grade 1, 24.3% were grade 2 and 1.8% were grade 3. The majority of the cases had a cell dissociation pattern showing both a population of single carcinoma cells and cell clusters (65.9%). Practically all tumours had a granular chromatin pattern (94.7%) and a slightly irregular nuclear margin with folds and grooves (94%) irrespective of histological subtype and cytological grading. Nucleoli were mostly indistinct or small (74%), whereas 24.3% were noticeable and 1.7% abnormal. Practically all cases revealed some degree of pleomorphism with 74.3% showing mild and 22.4% a distinct pleomorphism. A small subgroup of IDC was classified as monomorphic (3.3%). Almost all tumours had nuclear sizes in the range of 2–4 × RBC (96.9%).

Conclusion:  Not all histological grade 1 carcinomas are cytological grade 1. About 25% were grade 2, and a small subpopulation reached grade 3. The typical/average findings in FNAC from grade 1 breast carcinomas were a population of both groups and single cells showing mild pleomorphism, granular chromatin, slightly irregular nuclear margin, indistinct nucleolus and nuclear size 2–4 × RBC.
Did elevated atmospheric CO2alter soil mineral weathering?: an analysis of 5‐year soil water chemistry data at Duke FACE study
Authors: OH NEUNG‐HWAN , HOFMOCKEL MICHAEL , LAVINE MICHAEL L. , RICHTER DANIEL D.
Published: October 2007

A principal driver of biogeochemical weathering of the Earth's crust is soil CO2, produced mainly by plant roots and soil heterotrophs, a water‐soluble gas that forms carbonic acid which reacts with soil minerals via cation exchange and mineral dissolution. We examined effects of elevated atmospheric CO2(ambient + 200 ppmv) in a young pine forest on belowground carbonic acid chemistry of soil water. Soil water was collected every 2–3 weeks over a 5‐year period from O horizons and at 15, 70, and 200 cm in mineral soils at the Duke free air CO2enrichment facility located in a warm temperate climate in North Carolina, USA. Concentrations of major ions were volume‐weighted and statistically analyzed using linear mixed‐effects models. Experimental interest was placed on interactive effects of CO2treatment and time: to test effects of gradually increasing CO2in deep soil horizons where CO2is highest in concentration, and to protect against inherent plot‐to‐plot differences in soil water chemistry being interpreted as responses to CO2treatments. Although significant time‐dependent interactive effects were reported for soil CO2, interactive effects were not significant for soil water constituents. These data, combined with limited pretreatment sampling of soil water chemistry and recently determined large heterogeneity in soil solid chemistry at this site, indicate that CO2‐weathering response is smaller than the more‐than‐doubling of weathering reported previously and that increases in weathering are masked byin situsoil heterogeneity. Although the hypothesis that elevated CO2increases cation leaching and weathering dissolution is supported in laboratory experiments and field studies, quantifying the stimulation of chemical weathering by elevated atmospheric CO2remains to be tested rigorously in the field.
Quantifying carbon sequestration as a result of soil erosion and deposition: retrospective assessment using caesium‐137 and carbon inventories
Authors: QUINE TIMOTHY ANDREW , Van OOST KRISTOF
Published: October 2007

The role of soil erosion in the global carbon cycle remains a contested subject. A new approach to the retrospective derivation of erosion‐induced quantitative fluxes of carbon between soil and atmosphere is presented and applied. The approach is based on the premise that soil redistribution perturbs the carbon cycle by driving disequilibrium between soil carbon content and input. This perturbation is examined by establishing the difference between measured carbon inventories and the inventories that would be found if input and content were in dynamic equilibrium. The carbon inventory of a profile in dynamic equilibrium is simulated by allowing lateral and vertical redistribution of carbon but treating all other profile inputs as equal to outputs. Caesium‐137 is used to derive rates of vertical and lateral soil redistribution. Both point and field‐scale estimates of carbon exchange with the atmosphere are derived using the approach for a field subject to mechanized agricultural in the United Kingdom. Sensitivity analysis is undertaken and demonstrates that the approach is robust. The results indicate that, despite a 15% decline in the carbon content of the cultivation layer of the eroded part of the field, this area has acted as a net sink of 11 ± 2 g C m−2 yr−1 over the last half century and that in the field as a whole, soil redistribution has driven a sink of 7 ± 2 g C m−2 yr−1 (6 ± 2 g C m−2 yr−1 if all eroded carbon transported beyond the field boundary is lost to the atmosphere) over the same period. This is the first empirical evidence for, and quantification of, dynamic replacement of eroded carbon. The relatively modest field‐scale net sink is more consistent with the identification of erosion and deposition as a carbon sink than a carbon source. There is a clear need to assemble larger databases with which to evaluate critically the carbon sequestration potential of erosion and deposition in a variety of conditions of agricultural management, climate, relief, and soil type. In any case, this study demonstrated that the operation of erosion and deposition processes within the boundaries of agricultural fields must be understood as a key driver of the net carbon cycle consequences of cultivating land.
Latitudinal differentiated water table control of carbon dioxide, methane and nitrous oxide fluxes from hydromorphic soils: feedbacks to climate change
Authors: JUNGKUNST HERMANN F. , FIEDLER SABINE
Published: October 2007

The possibility of carbon (C) being locked away from the atmosphere for millennia is given in hydromorphic soils. However, the water‐table‐dependent feedback from soil organic matter (SOM) decomposition to the climate system is less clear. At least three greenhouse gases are produced: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gases show emission peaks at different water table positions and have different global warming potentials (GWP), for example a factor of 23 for CH4 and 296 for N2O as compared with the equivalent mass of CO2 on a 100‐year time horizon. This review of available annual data on all three gases revealed that the radiative forcing effect of SOM decomposition is principally dictated by CO2 despite its low GWP. Anaerobic SOM decomposition generally has a lower potential feedback to the climatic system than aerobic SOM decomposition. Concrete values are constrained by a lack of data from tropical and subarctic regions. Furthermore, data on N2O and on plant effects are generally rare. However, there is a clear latitudinal differentiation for the GWP of soils under anaerobic conditions compared with aerobic conditions when looking at CO2 and CH4: in the tropical and temperate regions, the anaerobic GWP showed a range of 25–60% of the aerobic value, but values varied between 80% and 110% in the boreal zone. Hence, particularly in the vulnerable boreal zone, the feedback from ecosystems to climate change will highly depend on plant responses to changing water tables at elevated temperatures.
Platelet‐derived growth factor receptors and ligands are up‐regulated in paediatric fibromatoses
Authors: Gibson S , Sebire N J , Anderson J
Published: October 2007

Aims:  Platelet‐derived growth factors (PDGF) and their receptors (PDGFR) play an essential role in pathways involved in the regulation of cell proliferation, growth and function. Overexpression of PDGF/R is reported in a wide range of solid tumours. The aim was to determine levels of PDGF/R expression in paediatric fibromatoses and myofibromatosis.

Methods and results:  Quantitative real‐time polymerase chain reaction was used to examine the expression level of α and β isoforms of PDGF/R in 17 fibromatoses, four myofibromatoses and three dermatofibrosarcoma protuberans (DFSP) in children. Fifteen of 17 (88%) fibromatoses and all myofibromatoses and DFSPs demonstrated increased expression of PDGFα and β compared with a panel of normal tissues. In terms of the cognate receptors, 13/17 (76%) fibromatoses demonstrated increased expression for PDGFRα and Rβ, whereas 3/4 myofibromatoses demonstrated increased expression of PDGFRα and all four had increased PDGFRβ expression. All DFSPs were associated with increased expression of both PDGFRα and PDGFRβ compared with normal control tissues.

Conclusions:  Increased expression of PDGF/Rαβ may play an important role in the mechanism of growth of these paediatric fibromatous lesions and warrants further investigation, since novel therapeutic interventions could potentially be developed in the light of the expression patterns.
Angiogenesis and mast cells in human breast cancer sentinel lymph nodes with and without micrometastases
Authors: Ribatti D , Finato N , Crivellato E , Guidolin D , Longo V , Mangieri D , Nico B , Vacca A , Beltrami C A
Published: October 2007

Aims:  An increasing number of mast cells have been reported in angiogenesis associated with solid and haematopoietic tumours. Data concerning the number of mast cells in neoplastic lymph nodes and their relationship with microvessel density are controversial. The aim was to correlate the extent of angiogenesis with the number of mast cells reactive with tryptase in biopsy specimens of sentinel lymph nodes with and without micrometastases obtained from patients with breast cancer.

Methods and results:  Specimens from sentinel lymph nodes obtained from 80 patients (40 with and 40 without micrometastases) were investigated immunohistochemically by using anti‐CD31 and anti‐tryptase antibodies. Angiogenesis, measured as microvessel counts, increased in parallel with the number of tryptase‐positive mast cells and their values were significantly higher in lymph nodes with micrometastases compared with those without.

Conclusions:  Tryptase‐positive mast cells may contribute, at least in part, to angiogenesis occurring in sentinel lymph nodes with micrometastases from patients with breast cancer.
CD4+ T‐cell‐dependent tumour rejection in an immune‐privileged environment requires macrophages
Authors: Dace Dru S. , Chen Peter W. , Niederkorn Jerry Y.
Published: October 2007

Although intraocular tumours reside in an immune‐privileged site, they can circumvent immune privilege and undergo rejection. Ocular tumour rejection typically follows one of two pathways. One pathway involves CD4+ T cells, delayed‐type hypersensitivity (DTH), and culmination in ischemic necrosis of the tumour and phthisis (atrophy) of the eye. The second pathway is DTH‐independent and does not inflict collateral injury to ocular tissues, and the eye is preserved. In this study, we used a well‐characterized tumour, Ad5E1, to investigate the role of CD4+ T cells in the non‐phthisical form of intraocular tumour rejection. It has been previously documented that CD4+ T cells and interferon (IFN)‐γ are necessary for rejection of these tumours in the eye. In this study, we demonstrate that CD4+ T cells can circumvent immune privilege and infiltrate intraocular Ad5E1 tumours. Following tumour rejection, CD4+ T cells from tumour rejector mice could be adoptively transferred to severe combined immunodeficiency (SCID) mice and protect them from intraocular Ad5E1 tumour growth. Tumour‐specific CD4+ T cells produced IFN‐γ in response to Ad5E1 tumour antigens. Macrophages also contributed to rejection, as they were present in intraocular Ad5E1 tumours, and local depletion of macrophages resulted in progressive tumour growth. Ocular macrophages contributed to Ad5E1 tumour rejection, as Ad5E1 tumour rejection did not occur in macrophage‐depleted SCID mice reconstituted with rejector CD4+ T cells. This demonstrates that macrophage and CD4+ T‐cell co‐operation is needed for non‐phthisical rejection of intraocular tumours.
β7‐integrin‐independent enhancement of mucosal and systemic anti‐HIV antibody responses following combined mucosal and systemic gene delivery
Authors: Goodsell Amanda , Zhou Fengmin , Gupta Soumi , Singh Manmohan , Malyala Padma , Kazzaz Jina , Greer Catherine , Legg Harold , Tang Tony , Zur Megede January , Srivastava Ranjana , Barnett Susan W. , Donnelly John J. , Luciw Paul A. , Polo John , O'Hagan Derek T. , Vajdy Michael
Published: October 2007

Vaccination strategies that can block or limit heterosexual human immunodeficiency virus (HIV) transmissions to local and systemic tissues are the goal of much research effort. Herein, in a mouse model, we aimed to determine whether the enhancement of antibody responses through mucosal and systemic immunizations, previously observed with protein‐based vaccines, applies to immunizations with DNA‐ or RNA‐based vectors. Intranasal (i.n.) followed by intramuscular (i.m.) immunizations (i.n./i.m.) with polylactide‐coglycolide (PLG)‐DNA microparticles encoding HIV‐gag (PLG‐DNA‐gag) significantly enhanced serum antibody responses, compared with i.m., i.n. or i.m. followed by i.n. (i.m./i.n.) immunizations. Moreover, while i.n./i.m., i.n. or i.m./i.n. immunizations with PLG‐DNA‐gag resulted in genital tract antibody responses, i.m. immunizations alone failed to do so. Importantly, β7‐deficient mice developed local and systemic antibody responses following i.n./i.m. immunization, or immunization via any other route, similar to those of wild‐type mice. To compare the DNA with an RNA delivery system, immunizations were performed with VEE/SIN‐gag replicon particles, composed of Venezuelan equine encephalitis virus (VEE) replicon RNA and Sindbis surface structure (SIN). i.n./i.m., compared with any other immunizations, i.n./i.m. immunization with VEE/SIN‐gag resulted in enhanced genital tract but not serum antibody responses. These data show for the first time that mucosal followed by systemic immunizations with gene delivery systems enhance B‐cell responses independent of the mucosal homing receptors α4β7 and αEβ7.
The effects of livestock grazing on foliar arthropods associated with bird diet in upland grasslands of Scotland
Authors: Dennis Peter , Skartveit John , McCracken David I. , Pakeman Robin J. , Beaton Katy , Kunaver Anja , Evans Darren M.
Published: October 2007

Upland biotopes have conservation importance for their typical plant and animal species. Recently, the condition of upland habitats has deteriorated with associated declines in many upland birds. Grazing by increased densities of sheep has been implicated in these changes. Studies in lowland agricultural land have shown a link between declines in bird populations and the availability of arthropod prey.

We studied the effect of three grazing regimes and an ungrazed control, each replicated six times in a total of 24 3·3‐ha plots, on the numbers and overall biomass of foliar arthropods in upland grassland in the Southern Highlands.

The three grazed treatments of the experiment were stocked with the commercial stocking density of sheep, one‐third of the commercial stocking density by sheep only and one‐third of the commercial stocking density by sheep and cattle.

Arthropod groups recognized as components of the diet of moorland birds were sampled by motorized suction sampler and sweep net. Arthropod numbers were unaffected by grazing treatments 6 months after grazing commenced. Significant grazing treatment effects on spiders, bugs and beetles were observed in years 2 and 3, with higher numbers in the less‐grazed treatments, but no such effect on brachyceran flies, caterpillars and craneflies.

A residual maximum likelihood (REML) analysis related the numbers of spiders, bugs, beetles, craneflies and caterpillars to either the stocking density of sheep or an interaction of sheep with year. The analysis related bugs and brachyceran flies to an interaction between cattle stocking density and year.

Estimated total biomass of foliar arthropods increased significantly with decreasing grazing intensity in years 2 and 3 and biomass in the ungrazed treatment was approximately twice that in the commercially grazed treatment. The REML analysis related biomass to the stocking density of sheep and both the stocking density of sheep and of cattle in an interaction with year.

Synthesis and applications. We demonstrated that the stocking density and inclusion of cattle grazing affects the numbers and biomass of particular foliar arthropods in the uplands of Scotland. Grazing management is important not only for the conservation of arthropods per se but also as food for insectivorous birds of conservation concern.
Habitat invasions by alien plants: a quantitative comparison among Mediterranean, subcontinental and oceanic regions of Europe
Authors: Chytrý Milan , Maskell Lindsay C. , Pino Joan , Pyšek Petr , Vilà Montserrat , Font Xavier , Smart Simon M.
Published: October 2007

Although invasions by alien plants are major threats to the biodiversity of natural habitats, individual habitats vary considerably in their susceptibility to invasion. Therefore the risk assessment procedures, which are used increasingly by environmental managers to inform effective planning of invasive plant control, require reliable quantitative information on the extent to which different habitats are susceptible to invasion. It is also important to know whether the levels of invasion in different habitats are locally specific or consistent among regions with contrasting climate, flora and history of human impact.

We compiled a database of 52 480 vegetation plots from three regions of Europe: Catalonia (Mediterranean–submediterranean region), Czech Republic (subcontinental) and Great Britain (oceanic). We classified plant species into neophytes, archaeophytes and natives, and calculated the proportion of each group in 33 habitats described by the European Nature Information System (EUNIS) classification.

Of 545 alien species found in the plots, only eight occurred in all three regions. Despite this large difference in species composition, patterns of habitat invasions were highly consistent between regions. None or few aliens were found in environmentally extreme and nutrient‐poor habitats, e.g. mires, heathlands and high‐mountain grasslands. Many aliens were found in frequently disturbed habitats with fluctuating nutrient availability, e.g. in man‐made habitats. Neophytes were also often found in coastal, littoral and riverine habitats.

Neophytes were found commonly in habitats also occupied by archaeophytes. Thus, the number of archaeophytes can be considered as a good predictor of the neophyte invasion risk. However, neophytes had stronger affinity to wet habitats and disturbed woody vegetation while archaeophytes tended to be more common in dry to mesic open habitats.

Synthesis and applications. The considerable inter‐regional consistency of the habitat invasion patterns suggests that habitats can be used as a good predictor for the invasion risk assessment. This finding opens promising perspectives for the use of spatially explicit information on habitats, including scenarios of future land‐use change, to identify the areas of highest risk of invasion.
Vascular plant and Orthoptera diversity in relation to grassland management and landscape composition in the European Alps
Authors: Marini Lorenzo , Fontana Paolo , Scotton Michele , Klimek Sebastian
Published: October 2007

Several recent studies have considered the relative effects of local vs. landscape factors on diversity of several animal taxa in grasslands. However, very few have considered vascular plant or Orthoptera species, both of which are important biotic components of grassland ecosystems. The general aim of this study was to determine the effect of grassland management and landscape composition, and their potential interactions, on diversity patterns of vascular plants and Orthoptera in Alpine hay meadows.

We considered three groups of management regimes defined by different amounts of fertilizer nitrogen applied and cutting frequency: (i) extensive, (ii) low intensive and (iii) intensive meadows situated in different landscape contexts. To evaluate the relative importance of meadow management and landscape composition on diversity patterns, we applied analysis of covariance and variation partitioning analyses.

Diversity patterns of both taxonomic groups were affected primarily by grassland management. The extensive management regime was most suitable for conserving high species richness of both taxonomic groups. The intensive meadows were characterized by plant communities dominated by a few ruderal and competitor species, and by Orthoptera communities composed of only a few abundant Caelifera species (e.g. Chorthippus parallelus), while Ensifera species had very low individual densities.

Regarding the landscape determinants, plant diversity patterns were not significantly related to any landscape composition variables. In contrast, a high proportion of urban elements and grassland in the surrounding landscape (radius 500 m) affected Orthoptera species richness negatively.

Synthesis and applications. The implementation of well‐targeted agri‐environment schemes for compensation payments against intensification and abandonment of extensive hay meadows seems to be a promising tool to protect both taxonomic groups. In this context, we suggest that the existing Swiss ecological compensation area (ECA) hay meadow agri‐environment scheme, which requires at least one cut every year and no fertilizer application, might also be suitable for the Italian Alps. Moreover, the significant influence of landscape composition on Orthoptera diversity suggests that the effectiveness of measures applied at a field scale may be improved by integration of protected area schemes, promoting extensive management at a farm scale.
Fostering elementary school students’ understanding of simple electricity by combining simulation and laboratory activities
Authors: Jaakkola T. , Nurmi S.
Published: October 2007

Abstract  Computer simulations and laboratory activities have been traditionally treated as substitute or competing methods in science teaching. The aim of this experimental study was to investigate if it would be more beneficial to combine simulation and laboratory activities than to use them separately in teaching the concepts of simple electricity. Based on their pre‐test performances, 66 elementary school students were placed into three different learning environments: computer simulation, laboratory exercise and a simulation–laboratory combination. The results showed that the simulation–laboratory combination environment led to statistically greater learning gains than the use of either simulation or laboratory activities alone, and it also promoted students’ conceptual understanding most efficiently. There were no statistical differences between simulation and laboratory environments. The results highlight the benefits of using simulation along with hands‐on laboratory activities to promote students’ understanding of electricity. A simulation can help students to first understand the theoretical principles of electricity; however, in order to promote conceptual change, it is necessary to challenge further students’ intuitive conceptions by demonstrating through testing that the laws and principles that are discovered through a simulation also apply in reality.
WebQuests as perceived by teachers: implications for online teaching and learning
Authors: Zheng R. , Perez J. , Williamson J. , Flygare J.
Published: October 2007

Abstract  The WebQuest as an instructional tool has recently been widely adopted in K‐16 education. However, its underlying principles and functionality are not well understood, which has resulted in an inconsistency in practice. This study identifies the underlying constructs of WebQuests as perceived by teachers and variables affecting their perceptions on WebQuests. A survey was conducted on teachers (n = 226) recruited from one large research university in the USA and a professional listserv. The findings reveal three constructs perceived by teachers as critical to WebQuests: constructivist problem solving, social interaction and scaffolded learning. Results also show that variables like purpose of WebQuest use, years of teaching, years of WebQuest use and gender predict, at various degrees, teachers’ perceptions on WebQuests. Discussions are made on how the constructs identified can be used to improve online teaching and learning. Suggestions for future study are included by examining the influences of social, psychological and affective factors on learners’ learning in WebQuests.
An enhanced Bayesian model to detect students’ learning styles in Web‐based courses
Authors: García P. , Schiaffino S. , Amandi A.
Published: October 2007

Abstract  Students acquire and process information in different ways depending on their learning styles. To be effective, Web‐based courses should guarantee that all the students learn despite their different learning styles. To achieve this goal, we have to detect how students learn: reflecting or acting; steadily or in fits and starts; intuitively or sensitively. In a previous work, we have presented an approach that uses Bayesian networks to detect a student's learning style in Web‐based courses. In this work, we present an enhanced Bayesian model designed after the analysis of the results obtained when evaluating the approach in the context of an Artificial Intelligence course. We evaluated the precision of our Bayesian approach to infer students’ learning styles from the observation of their actions with a Web‐based education system during three semesters. We show how the results from one semester enabled us to adjust our initial model and helped teachers improve the content of the course for the following semester, enhancing in this way students’ learning process. We obtained higher precision values when inferring the learning styles with the enhanced model.
Phylogeography of Iris missouriensis (Iridaceae) based on nuclear and chloroplast markers
Authors: CORNMAN R. SCOTT , ARNOLD MICHAEL L.
Published: October 2007

We investigated the phylogeography of Iris missouriensis (Iridaceae), which is widely distributed in western North America. We utilized transposon display and DNA sequencing to quantify nuclear and chloroplast genetic structure. Our objectives were (i) to characterize the geographic structure of genetic variation throughout the species range, (ii) to test whether both margins of the range show reduced genetic diversity as predicted by north–south expansion and contraction associated with climate change, and (iii) to determine whether the subspecies Iris missouriensis ssp. longipetala is genetically distinct. We found that genetic diversity was significantly lower in the northern part of the range but was not significantly different between the central and southern regions, indicating greater stability of the southern margin vs. the northern. Among‐population differentiation was high (ΦPT = 0.52). The largest divisions in each marker set were concordant and separated the southern Rocky Mountains and Basin and Range provinces from the remainder of the range. The boundaries of this phylogeographic break do not coincide with gaps in present‐day distributions or phylogeographic breaks identified in other species, and may indicate a measure of reproductive isolation. Consistent with current treatments, we did not find support for the taxonomic placement of I. missourienis ssp. longipetala as a distinct species. Although transposon display has been used to investigate relationships among crop accessions and their wild relatives, to our knowledge, this is the first use of these markers for population‐level phylogeography of a nonmodel species and further demonstrates their utility in species recalcitrant to amplified fragment length polymorphism protocols.
Genetic analysis of potential postglacial watershed crossings in Central Europe by the bullhead (Cottus gobioL.)
Authors: VONLANTHEN P. , EXCOFFIER L. , BITTNER D. , PERSAT H. , NEUENSCHWANDER S. , LARGIADÈR C. R.
Published: October 2007

Natural colonizations across watersheds have been frequently proposed to explain the present distributions of many freshwater fish species. However, detailed studies of such potential watershed crossings are still missing. Here, we investigated potential postglacial watershed crossings of the widely distributed European bullhead (Cottus gobioL.) in two different areas along the Rhine–Rhône watershed using detailed genetic analysis. The main advantage of studying bullheads vs. other freshwater fish species is that their distribution has been lightly influenced by human activities and as such, interpretations of colonization history are not confounded by artificial transplantations. The genetic analyses of eight microsatellite loci revealed strong genetic similarities between populations of both sides of the Rhine–Rhône watershed in the Lake Geneva area, giving strong evidence for a natural watershed crossing of bullheads from the upper Rhine drainage into the Rhône drainage in the Lake Geneva area likely facilitated by the retreat of the glaciers after the last glacial maximum some 20 000 years ago. Populations from the Lake Geneva basin were genetically more similar to populations from across the watershed in the upper Rhine drainage than to populations further downstream in the lower Rhône. In contrast, populations from Belfort, an area, which was not covered by ice during the last glacial maximum, showed strong genetic differentiation between populations of the upper Rhine and Rhône drainages. Based on our results on the bullhead, we propose that glacial retreat may have eased the dispersal of numerous European freshwater fish species across several geological boundaries.
Standardizing methods to address clonality in population studies
Authors: ARNAUD‐HAOND S. , DUARTE C. M. , ALBERTO F. , SERRÃO E. A.
Published: October 2007

Although clonal species are dominant in many habitats, from unicellular organisms to plants and animals, ecological and particularly evolutionary studies on clonal species have been strongly limited by the difficulty in assessing the number, size and longevity of genetic individuals within a population. The development of molecular markers has allowed progress in this area, and although allozymes remain of limited use due to their typically low level of polymorphism, more polymorphic markers have been discovered during the last decades, supplying powerful tools to overcome the problem of clonality assessment. However, population genetics studies on clonal organisms lack a standardized framework to assess clonality, and to adapt conventional data analyses to account for the potential bias due to the possible replication of the same individuals in the sampling. Moreover, existing studies used a variety of indices to describe clonal diversity and structure such that comparison among studies is difficult at best. We emphasize the need for standardizing studies on clonal organisms, and particularly on clonal plants, in order to clarify the way clonality is taken into account in sampling designs and data analysis, and to allow further comparison of results reported in distinct studies. In order to provide a first step towards a standardized framework to address clonality in population studies, we review, on the basis of a thorough revision of the literature on population structure of clonal plants and of a complementary revision on other clonal organisms, the indices and statistics used so far to estimate genotypic or clonal diversity and to describe clonal structure in plants. We examine their advantages and weaknesses as well as various conceptual issues associated with statistical analyses of population genetics data on clonal organisms. We do so by testing them on results from simulations, as well as on two empirical data sets of microsatellites of the seagrasses Posidonia oceanica and Cymodocea nodosa. Finally, we also propose a selection of new indices and methods to estimate clonal diversity and describe clonal structure in a way that should facilitate comparison between future studies on clonal plants, most of which may be of interest for clonal organisms in general.
Diversity of fungi in hair roots of Ericaceae varies along a vegetation gradient
Authors: BOUGOURE DAMIAN S. , PARKIN PAMELA I. , CAIRNEY JOHN W. G. , ALEXANDER IAN J. , ANDERSON IAN C.
Published: October 2007

Ericaceous dwarf shrubs including Calluna vulgaris and Vaccinium spp. occur both in open heathland communities and in forest ecosystems as understorey vegetation. Ericaceous shrubs were once thought to form ericoid mycorrhizal associations with a relatively narrow range of ascomycetous fungi closely related to, and including, Rhizoscyphus ericae. However, perceptions have recently changed since the realization that a broader range of ascomycete fungi, and in some cases basidiomycete fungi, can also form associations with the roots of ericaceous plants. We used a combination of molecular approaches, including denaturing gradient gel electrophoresis, terminal restriction fragment length polymorphism, cloning and sequencing, to investigate the diversity of fungi associated with C. vulgaris roots collected across a heathland/native Scots pine forest vegetation gradient. We also determined differences in fungal community composition between roots of co‐occurring C. vulgaris and Vaccinium myrtillus in the forest understorey. Collectively, the data show that a large diversity of potentially ericoid mycorrhizal fungal taxa associate with roots of C. vulgaris and V. myrtillus, and that ascomycetes were about 2.5 times more frequent than basidiomycetes. The assemblages of fungi associated with C. vulgaris and V. myrtillus were different. In addition, the community of fungi associated with C. vulgaris hair roots was different for samples collected from the forest, open heathland and a transition zone between the two. This separation was partly, but not entirely, due to the occurrence of typical ectomycorrhizal basidiomycetes associated with the hair roots of C. vulgaris in the forest understorey. These data demonstrate that forest understorey ericaceous shrubs associate with a diverse range of ascomycete and basidiomycete taxa, including typical ectomycorrhizal basidiomycetes.
Population genetics and phylogeography of sea turtles
Authors: BOWEN B. W. , KARL S. A.
Published: October 2007

The seven species of sea turtles occupy a diversity of niches, and have a history tracing back over 100 million years, yet all share basic life‐history features, including exceptional navigation skills and periodic migrations from feeding to breeding habitats. Here, we review the biogeographic, behavioural, and ecological factors that shape the distribution of genetic diversity in sea turtles. Natal homing, wherein turtles return to their region of origin for mating and nesting, has been demonstrated with mtDNA sequences. These maternally inherited markers show strong population structure among nesting colonies while nuclear loci reveal a contrasting pattern of male‐mediated gene flow, a phenomenon termed ‘complex population structure’. Mixed‐stock analyses indicate that multiple nesting colonies can contribute to feeding aggregates, such that exploitation of turtles in these habitats can reduce breeding populations across the region. The mtDNA data also demonstrate migrations across entire ocean basins, some of the longest movements of marine vertebrates. Multiple paternity occurs at reported rates of 0–100%, and can vary by as much as 9–100% within species. Hybridization in almost every combination among members of the Cheloniidae has been documented but the frequency and ultimate ramifications of hybridization are not clear. The global phylogeography of sea turtles reveals a gradient based on habitat preference and thermal regime. The cold‐tolerant leatherback turtle (Dermochelys coriacea) shows no evolutionary partitions between Indo‐Pacific and Atlantic populations, while the tropical green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and ridleys (Lepidochelys olivaceavs.L. kempi) have ancient separations between oceans. Ridleys and loggerhead (Caretta caretta) also show more recent colonization between ocean basins, probably mediated by warm‐water gyres that occasionally traverse the frigid upwelling zone in southern Africa. These rare events may be sufficient to prevent allopatric speciation under contemporary geographic and climatic conditions. Genetic studies have advanced our understanding of marine turtle biology and evolution, but significant gaps persist and provide challenges for the next generation of sea turtle geneticists.
Population history of Berthelot's pipit: colonization, gene flow and morphological divergence in Macaronesia
Authors: ILLERA JUAN CARLOS , EMERSON BRENT C. , RICHARDSON DAVID S.
Published: October 2007

The fauna of oceanic islands provide exceptional models with which to examine patterns of dispersal, isolation and diversification, from incipient speciation to species level radiations. Here, we investigate recent differentiation and microevolutionary change in Berthelot's pipit (Anthus berthelotii), an endemic bird species inhabiting three Atlantic archipelagos. Mitochondrial DNA sequence data and microsatellite markers were used to deduce probable colonization pathway, genetic differentiation, and gene flow among the 12 island populations. Phenotypic differentiation was investigated based on eight biologically important morphological traits. We found little mitochondrial DNA variability, with only one and four haplotypes for the control region and cytochromeb, respectively. However, microsatellite data indicated moderate population differentiation (FST = 0.069) between the three archipelagos that were identified as genetically distinct units with limited gene flow. Both results, combined with the estimated time of divergence (2.5 millions years ago) from theAnthus campestris(the sister species), suggest that this species has only recently dispersed throughout these islands. The genetic relationships, patterns of allelic richness and exclusive alleles among populations suggest the species originally colonized the Canary Islands and only later spread from there to the Madeiran archipelago and Selvagen Islands. Differentiation has also occurred within archipelagos, although to a lesser degree. Gene flow was observed more among the eastern and central islands of the Canaries than between these and the western islands or the Madeiran Islands. Morphological differences were also more important between than within archipelagos. Concordance between morphological and genetic differentiation provided ambiguous results suggesting that genetic drift alone was not sufficient to explain phenotypic differentiation. The observed genetic and morphological differences may therefore be the result of differing patterns of selection pressures between populations, with Berthelot's pipit undergoing a process of incipient differentiation.