bluuebunny/crossref_metadata_2025 huggingface dataset:
Oestrogen receptors mediate oestrogen‐induced increases in post‐exercise rat skeletal muscle satellite cells
Authors: Enns D. L. , Iqbal S. , Tiidus P. M.
Published: April 2008

Aim:  Our laboratory recently demonstrated that increases in post‐exercise muscle satellite cell numbers are augmented by oestrogen. We investigated whether muscle oestrogen receptors (ORs) mediate this effect through administration of an OR antagonist, ICI 182,780.

Methods:  Ovariectomized female rats were divided into three groups: sham, oestrogen (0.25 mg pellet) and oestrogen plus OR blocker (ICI 182,780). Each group was divided into control and exercised groups. ICI 182,780 (5 mg kg−1 sc) was administered 1 day prior to and 6 days following oestrogen pellet implantation. After 8 days of oestrogen exposure, animals ran downhill for 90 min (17 m min−1, −13.5° grade) on a treadmill. Soleus and white vastus muscles were removed 24 and 72 h post‐exercise and immunostained for total (Pax7), activated (MyoD) and proliferating (BrdU) satellite cells. Muscle damage was indirectly assessed by measuring β‐glucuronidase activity. Two markers (His48 and ED1) of leucocyte infiltration were also examined.

Results:  β‐Glucuronidase activities and His48+ and ED1+ leucocytes increased post‐exercise, and these increases were attenuated with oestrogen. ICI 182,780 did not influence the attenuating effect of oestrogen on leucocyte infiltration or β‐glucuronidase activities in muscle. Total (Pax7+), activated (MyoD+) and proliferating (BrdU+) satellite cells increased post‐exercise, and these increases were augmented with oestrogen. Interestingly, ICI 182,780 abolished both exercise‐ and oestrogen‐mediated increases in these satellite cell markers.

Conclusion:  Oestrogen may augment increases in muscle satellite cells following exercise through OR‐mediated mechanisms; furthermore, the attenuation of post‐exercise muscle damage and leucocyte infiltration by oestrogen appears to be a non‐OR‐mediated process.
Impacts of Alternative Manure Application Rates on Texas Animal Feeding Operations: A Macro Level Analysis1
Authors: Osei E. , Du B. , Bekele A. , Hauck L. , Saleh A. , Tanter A.
Published: April 2008

Abstract:  An integrated economic and environmental modeling system was developed for evaluating agro‐environmental policies and practices implemented on large scales. The modeling system, the Comprehensive Economic and Environmental Optimization Tool‐Macro Modeling System (CEEOT‐MMS), integrates the Farm‐level Economic Model (FEM) and the Agricultural Policy Environmental eXtender (APEX) model, as well as national databases and clustering and aggregation algorithms. Using micro simulations of statistically derived representative farms and subsequent aggregation of farm‐level results, a wide range of agricultural best management practices can be investigated within CEEOT‐MMS. In the present study, CEEOT‐MMS was used to evaluate the economic and water quality impacts of nitrogen (N) and phosphorus (P) based manure application rates when implemented on all animal feeding operations in the State of Texas. Results of the study indicate that edge‐of‐field total P losses can be reduced by about 0.8 kg/ha/year or 14% when manure applications are calibrated to supply all of the recommended crop P requirements from manure total P sources only, when compared to manure applications at the recommended crop N agronomic rate. Corresponding economic impacts are projected to average a US$4,800 annual cost increase per farm. Results are also presented by ecological subregion, farm type, and farm size categories.
A Comparison of Single and Multiple Habitat Protocols for Collecting Macroinvertebrates in Wadeable Streams1
Authors: Blocksom Karen A. , Autrey Bradley C. , Passmore Margaret , Reynolds Lou
Published: April 2008

Abstract:  In 2003, we compared two benthic macroinvertebrate sampling methods that are used for rapid biological assessment of wadeable streams. A single habitat method using kick sampling in riffles and runs was compared to a multiple habitat method that sampled all available habitats in proportion of occurrence. Both methods were performed side‐by‐side at 41 sites in lower gradient streams of the Piedmont and Northern Piedmont ecoregions of the United States, where riffle habitat is less abundant. Differences in sampling methods were examined using similarity indices, two multimetric indices [the family‐level Virginia Stream Condition Index (VSCI) and the species‐level Macroinvertebrate Biotic Integrity Index (MBII)], their component metrics, and bioassessment endpoints based on each index. Index scores were highly correlated between single and multiple habitat field methods, and sampling method comparability, based on comparison of similarities between and within sampling methods, was particularly high for species level data. The VSCI scores and values of most of its component metrics were not significantly higher for one particular method, but relationships between single and multiple habitat values were highly variable for percent Ephemeroptera, percent chironomids, and percent Plecoptera and Trichoptera (Hydropsychidae excluded). A similar level of variability in the relationship was observed for the MBII and most of its metrics, but Ephemeroptera richness, percent individuals in the dominant five taxa, and Hilsenhoff Biotic Index scores all exhibited differences in values between single and multiple habitat field methods. When applied to multiple habitat samples, the MBII exhibited greater precision, higher index scores, and higher assessment categories than when applied to single habitat samples at the same sites. In streams with limited or no riffle habitats, the multiple habitat method should provide an adequate sample for biological assessment, and at sites with abundant riffle habitat, little difference would be expected between the single and multiple habitat field methods. Thus, in geographic areas with a wide variety of stream types, the multiple habitat method may be more desirable. Even so, the variability in the relationship between single and multiple habitat methods indicates that the data are not interchangeable, and we suggest that any change in sampling method should be accompanied by a recalibration of any existing assessment tool (e.g., multimetric index) with data collected using the new method, regardless of taxonomic level.
Fecal Coliform Export From Four Coastal North Carolina Areas1
Authors: Line D.E. , White N.M. , Kirby‐Smith W.W. , Potts J.D.
Published: April 2008

Abstract:  Fecal coliform (FC) bacteria in coastal waters impair the use of these waters for shellfish harvesting and recreation. This study was designed to quantify and compare FC levels and export in two coastal watersheds with different land uses. Continuous monitoring of rainfall and discharge at three sites in the Jumping Run Creek watershed and one site in the Pettiford Creek watershed were conducted during a 4.5‐year period. Primary land use in the drainage area of one of the three Jumping Run Creek sites is low density industrial, while the other two are residential. Land use in the Pettiford Creek watershed is managed national forest. Nonstorm or base‐flow grab and flow‐proportional storm‐event samples were collected and analyzed for turbidity, conductivity, suspended sediment, nitrogen, phosphorus, and FC. Geometric mean FC levels for the Jumping Run Creek monitoring sites ranged from 593 to 2,096 mpn/100 ml, while the mean level at the Pettiford Creek site was 191 mpn/100 ml. Levels of most other parameters were greater in storm discharge from the Jumping Run Creek sites as compared to Pettiford Creek indicating that pollutant export from a watershed increases with development. Statistical analysis of the monitoring data suggested that FC levels in stormwater samples consistently increased with storm rainfall, but were not consistently correlated with any other parameter, including total suspended solids. Multivariate analysis indicated that the weekly FC export for each of the four sites was lowest during the December‐February quarter. Export was highest during the spring and summer at the Jumping Run Creek sites, while for the Pettiford Creek site, FC export was highest during September‐November. The cause of the seasonal variability was unknown but was thought to be associated with human activity in the watersheds.
Fine‐Sediment Loadings to Lake Tahoe1
Authors: Simon Andrew
Published: April 2008

Abstract:  Over the past 35 years, a trend of decreasing water clarity has been documented in Lake Tahoe, attributable in part to the delivery of fine‐grained sediments emanating from upland and channel sources. The overall objective of the research reported here was to determine the amount of fine sediment delivered to Lake Tahoe from each of the 63 contributing watersheds. The research described in this report used combinations of field‐based observations of channel and bank stability with measured and simulated data on fine‐sediment loadings to estimate fine‐sediment loadings from unmonitored basins throughout the Lake Tahoe Basin. Loadings were expressed in the conventional format of mass per unit time but also in the number of particles finer than 20 μm, the latter for future use in a lake‐clarity model. The greatest contributors of fine sediment happened to be those with measured data, not requiring extrapolation. In descending order, they are as follows: Upper Truckee River [1,010 tonnes per year (T/year)], Blackwood Creek (846 T/year), Trout Creek (462 T/year), and Ward Creek (412 T/year). Summing estimated values from the contributing watersheds provided an average, annual estimate of fine‐sediment (<0.063 mm) loadings to the lake of 5,206 T/year. A total of 7.79E + 19 particles in the 5‐20 μm fraction were calculated to enter Lake Tahoe in an average year with the Upper Truckee River accounting for almost 25% of the total. Contributions from Blackwood, Ward, Trout, and Third creeks account for another 23% of these very fine particles. Thus, these five streams making up about 40% of the basin area, account for almost 50% of all fine‐sediment loadings to the lake. Contribution of fine sediment from streambank erosion were estimated by developing empirical relations between measured or simulated bank‐erosion rates with a field‐based measure of the extent of bank instability along given streams. An average, annual fine‐sediment loading from streambank erosion of 1,305 T/year was calculated. This represents about 25% of the average, annual fine‐sediment load delivered to the lake from all sources. The two largest contributors, the Upper Truckee River (639 T/year) and Blackwood Creek (431 T/year), account for slightly more than 80% of all fines emanating from streambanks, representing about 20% of the fine sediment delivered to Lake Tahoe from all sources. Extrapolations of fine‐sediment loadings to the unmonitored watersheds are based on documented empirical relations, yet contain a significant amount of uncertainty. Except for those values derived directly from measured data, reported results should be considered as estimates.
Isolation and characterization of microsatellite markers from the marine isopodsSerolis paradoxaandSeptemserolis septemcarinata(Crustacea: Peracarida)
Authors: LEESE FLORIAN , KOP ANNA , AGRAWAL SHOBHIT , HELD CHRISTOPH
Published: April 2008

This study reports the successful isolation of highly informative microsatellite marker sets for two marine serolid isopod species. ForSerolis paradoxa(Fabricius, 1775), 13, and forSeptemserolis septemcarinata(Miers, 1875), eight polymorphic microsatellite markers were isolated using the reporter genome enrichment protocol. The number of alleles per locus (NA) and the observed heterozygosity (HO) encompass a wide range of variation withinS. paradoxa(NA3–31,HO6–89%) andS. septemcarinata(NA2–18,HO9–94%). The suitability of the newly isolated markers for population genetic studies is evaluated.
Isolation and characterization of 19 microsatellite markers in a tropical and warm subtropical birch, Betula alnoides Buch.–Ham. ex D. Don
Authors: GUO J. J. , ZENG J. , ZHOU S. L. , ZHAO Z. G.
Published: April 2008

Betula alnoides is an ecologically and economically important species in the tropics and warm subtropics. Nineteen polymorphic microsatellite markers were isolated from this species, which displayed three to 12 alleles per locus. The observed heterozygosities ranged from 0.100 to 0.905, and the expected heterozygosities from 0.510 to 0.893. These markers would be useful tools in genetic resource assessment, molecular marker‐assistant breeding, parentage analysis and genetic diversity studies for this species.
Cross‐amplification and characterization of 13 tetranucleotide microsatellites in multiple species of Neotropical canids
Authors: DA FONTOURA‐RODRIGUES MANOEL L. , LIMA‐ROSA CARLOS ANDRÉ V. , TCHAICKA LIGIA , VALDEZ FERNANDA P. , RODRIGUES FLÁVIO H. G. , DE PAULA ROGÉRIO C. , GOUGH MICHAEL P. , JOHNSON WARREN E. , BONATTO SANDRO L. , EIZIRIK EDUARDO
Published: April 2008

We tested 47 tetranucleotide microsatellite loci developed for the domestic dog in four species of Neotropical canids, aiming to produce a standardized set that could be successfully used even in noninvasive samples across this group. We identified 13 suitable loci, nine of which constitute a standardized set for all species. Considering only the ideal panel of nine loci, the mean expected heterozygosity (averaged across species) per locus ranged from 0.58 to 0.92 (overall mean 0.76), and the maximum probability of identity value was 1.3 × 10−9. This set of loci has a great potential for application in evolutionary, ecological and conservation studies.
incor: a computer program for testing differences among independent correlations
Authors: SILVER N. C. , ZAIKINA H. , HITTNER J. B. , MAY K.
Published: April 2008

An interactive fortran program (incor) performs the Paul (1989) procedure for testing the null hypothesis that more than two independent population correlations are equivalent. The program also performs subsequent range tests for comparing all possible pairwise correlations.
Isolation and characterization of highly polymorphic microsatellites in the chokka squid, Loligo reynaudii
Authors: NAUD MARIE‐JOSÉ , SHAW PAUL W.
Published: April 2008

The chokka squid, Loligo reynaudii, is the target of a commercially valuable fishery in South Africa, but little information is available on population structure and mating system. We developed 11 polymorphic microsatellite markers using both standard nonenrichment and enrichment protocols. Numbers of alleles per locus ranged from 11 to 30, and levels of expected heterozygosity ranged between 0.77 and 0.98. Three loci developed using an enriched library displayed significant departure from Hardy–Weinberg genotype proportions suggesting high frequencies of null alleles. The remaining loci should prove useful for population and parentage studies.
Isolation and characterization of microsatellite loci in Pitcairnia albiflos (Bromeliaceae), an endemic bromeliad from the Atlantic Rainforest, and cross‐amplification in other species
Authors: PAGGI G. M. , PALMA‐SILVA C. , BERED F. , CIDADE F. W. , SOUSA A. C. B. , SOUZA A. P. , WENDT T. , LEXER C.
Published: April 2008

Eight microsatellite markers were isolated from Pitcairnia albiflos, an endangered endemic bromeliad species restricted to ‘inselberg’ rock outcrops in the state of Rio de Janeiro, Brazil. The number of alleles observed for each locus ranged from two to 12. Average observed and expected heterozygosities were 0.408 and 0.663, respectively. The cross‐amplification test in 16 taxa suggests that the markers will be useful in numerous related bromeliad species. The loci will be used to study genetic structure and reproductive biology in fragmented inselberg populations and the origin and maintenance of barriers to gene flow between sympatric Pitcairnia species.
Unravelling below‐ground plant distributions: a real‐time polymerase chain reaction method for quantifying species proportions in mixed root samples
Authors: MOMMER L. , WAGEMAKER C. A. M. , DE KROON H. , OUBORG N. J.
Published: April 2008

Knowledge on below‐ground plant distributions is almost lacking to date, despite the fact that such information would be very valuable in understanding below‐ground competition and species‐specific interactions, processes that are expected to shape community structure. Methods available so far for below‐ground species determination have drawbacks that we tried to challenge. Some methods make use of differences in the chemical composition between species, but this is highly variable upon environmental factors. DNA‐based techniques — far less dependent on chemical composition — such as polymerase chain reaction on internal transcribed spacer (ITS) primers can so far only determine presence–absence of a species in a mixed root sample. Here, we present a quantitative DNA‐based technique that allows investigation of relative species abundances in experimental mixed root samples. We used quantitative real‐time polymerase chain reaction (PCR) on species‐specific markers obtained from intersimple sequence repeat (ISSR) analyses in root samples. This molecular technique is novel in the field of root ecology and its development overcame three challenges: (i) determination of species‐specific DNA fragments, (ii) development and optimization of the real time PCR protocol, (iii) designing a data treatment method based on a modified delta–delta‐cycle threshold (CT) analysis. The method gained robustness from using relative DNA abundances in species mixtures rather than absolute concentration readings. This requires accurate multispecies reference series as a calibration. Test samples with different known biomass ratios of all species showed proof of concept of this method. The pro's and contra's of this method are discussed in the light of its contribution to advancing ecological research on below‐ground plant–plant interactions.
Isolation and characterization of microsatellite markers in Acca sellowiana (Berg) Burret
Authors: SANTOS K. L. , SANTOS M. O. , LABORDA P. R. , SOUZA A. P. , PERONI N. , NODARI R. O.
Published: April 2008

Acca sellowiana has commercial potential due to the quality and the unique flavor of its fruit. Conservation of natural populations and management of breeding programmes would benefit from the availability of molecular markers that could be used to characterize levels and distribution of genetic variability. Thus, 13 microsatellite markers were developed from an enriched genomic library of A. sellowiana. They were characterized using 40 samples. The expected and observed heterozygosities ranged from 0.513 to 0.913 and from 0.200 to 0.889, respectively. These are the first microsatellite loci characterized from A. sellowiana that will contribute to improve researches on its genetic conservation, characterization and breeding.
Coincidence detection of convergent perforant path and mossy fibre inputs by CA3 interneurons
Authors: Calixto Eduardo , Galván Emilio J. , Card J. Patrick , Barrionuevo Germán
Published: April 2008

We performed whole‐cell recordings from CA3 s. radiatum (R) and s. lacunosum‐moleculare (L‐M) interneurons in hippocampal slices to examine the temporal aspects of summation of converging perforant path (PP) and mossy fibre (MF) inputs. PP EPSPs were evoked from the s. lacunosum‐moleculare in area CA1. MF EPSPs were evoked from the medial extent of the suprapyramidal blade of the dentate gyrus. Summation was strongly supralinear when examining PP EPSP with MF EPSP in a heterosynaptic pair at the 10 ms ISI, and linear to sublinear at longer ISIs. This pattern of nonlinearities suggests that R and L‐M interneurons act as coincidence detectors for input from PP and MF. Summation at all ISIs was linear in voltage clamp mode demonstrating that nonlinearities were generated by postsynaptic voltage‐dependent conductances. Supralinearity was not detected when the first EPSP in the pair was replaced by a simulated EPSP injected into the soma, suggesting that the conductances underlying the EPSP boosting were located in distal dendrites. Supralinearity was selectively eliminated with either Ni2+ (30 μm), mibefradil (10 μm) or nimodipine (15 μm), but was unaffected by QX‐314. This pharmacological profile indicates that supralinearity is due to recruitment of dendritic T‐type Ca2+channels by the first subthreshold EPSP in the pair. Results with the hyperpolarization‐activated (Ih) channel blocker ZD 7288 (50 μm) revealed that Ih restricted the time course of supralinearity for coincidently summed EPSPs, and promoted linear to sublinear summation for asynchronous EPSPs. We conclude that coincidence detection results from the counterbalanced activation of T‐type Ca2+ channels and inactivation of Ih.
Cytoplasmic calcium oscillations and store‐operated calcium influx
Authors: Putney James W. , Bird Gary S.
Published: April 2008

Intracellular calcium oscillations have fascinated scientists for decades. They provide an important cellular signal which, unlike most signalling mechanisms, is digitally encoded. While it is generally agreed that oscillations most frequently arise from cyclical release and re‐uptake of intracellularly stored calcium, it is becoming increasingly clear that influx of calcium across the plasma membrane also plays a critical role in their maintenance and even in delivering their signal to the correct cellular locus. In this review we will discuss the role played by Ca2+ entry mechanisms in Ca2+ oscillations, and approaches to understanding the molecular nature of this Ca2+ entry pathway.
Detection and Quantification of Group C Rotaviruses in Communal Sewage
Authors: Meleg Edina , Bányai Krisztián , Martella Vito , Jiang Baoming , Kocsis Béla , Kisfali Péter , Melegh Béla , Szűcs György
Published: April 2008

Group C rotaviruses have been recognized as a cause of acute gastroenteritis in humans, cattle, and swine, although the true epidemiologic and clinical importance of this virus in these hosts has not yet been fully established. A real-time PCR assay based on a broadly reactive primer pair was developed and used to quantitatively determine the viral load of group C rotaviruses in environmental samples. A total of 35 raw and 35 treated sewage samples collected at the same sampling time in four Hungarian sewage treatment plants during a survey in 2005 were tested for the presence of group C rotaviruses. The overall detection rates were 91% (32 of 35) for the influent and 57% (20 of 35) for the effluent samples. Molecular characterization of the amplified partial VP6 gene revealed the cocirculation of human and animal (i.e., bovine and porcine) strains that were easily distinguishable by melting curve analysis. Human strains yielded relatively high viral loads (mean, 1.2 × 10
7
; median, 6.9 × 10
5
genome equivalents per liter influent sewage) and appeared to display seasonal activity over the study period, whereas animal strains appeared to circulate throughout the year at much lower average titers (bovine strains mean, 9.9 × 10
4
; median, 3.0 × 10
4
; porcine strains mean, 3.9 × 10
4
; median, 3.1 × 10
4
genome equivalents per liter influent sewage). Our findings suggest that monitoring of communal sewage may provide a good surrogate for investigating the epidemiology and ecology of group C rotaviruses in humans and animals.
Effects of long-term training on neutrophil function in male university judoists
Authors: Yamamoto Y , Nakaji S , Umeda T , Matsuzaka M , Takahashi I , Tanabe M , Danjo K , Kojima A , Oyama T
Published: April 2008

Objectives:

To clarify the effects of high-intensity and high-frequency long-term/chronic training on neutrophil function and serum levels of myogenic enzymes in male university judoists.

Methods:

The subjects were 24 male judoists who had stopped judo training for 6 months and then restarted their training. The following parameters were examined before and after a 2 h unified exercise loading (UEL) at the beginning of the restarted quotidian training (pre-training) and at 2 months, 4 months and 6 months thereafter: myogenic enzymes, neutrophil and leucocyte counts, and neutrophil phagocytic activity (PA) and oxidative burst activity as a measure of reactive oxygen species (ROS) production capability.

Results:

Myogenic enzymes that were measured after UEL at all four points significantly increased except for creatine kinase at the 2-month point (p<0.01 in each) and neutrophil counts significantly increased after UEL at the pre-training, 2-month and 4-month points (p<0.01 in each), but these changes became smaller from the 2-month point. PA significantly decreased after UEL at the pre-training and 2-month points (p<0.01 in each), but no change was seen at the 4-month and 6-month points. On the other hand, no change in ROS production per cell after UEL was seen at the pre-training point, but it significantly increased after UEL at the 2-month, 4-month and 6-month points (p<0.01 in each).

Conclusion:

The changing rate of the levels of UEL-mediated myogenic enzymes, neutrophil mobilisation and neutrophil function was seen to decrease at the 2-month, 4-month and 6-month assessments, compared with the pre-training point: these may comprise at least some of the long-term training effects.
Maternal occupational exposures and risk of spontaneous abortion in veterinary practice
Authors: Shirangi A , Fritschi L , Holman C D J
Published: April 2008

Objectives:

To examine the relationship between occupational exposures and spontaneous abortion in female veterinarians.

Methods:

The Health Risks of Australian Veterinarians project (HRAV) was a questionnaire-based survey of all graduates from Australian veterinary schools from 1960 to 2000. Of 5748 eligible veterinarians sent the questionnaires, 2800 replied including 1197 females (42.8%). The response rate was 59% of women veterinarians eligible to participate. The pregnancy of women was defined as the unit of analysis. We restricted analyses to pregnancies of those women who reported being employed when the pregnancy began and were working only in clinical practice. Of 1355 pregnancies, 940 were eligible for the final analysis. Self-reported occupational exposures to anaesthetic gases,xrays, pesticides and long working hours in relation to spontaneous abortion were examined.

Results:

In a multiple logistic regression controlling for 12 potential confounders, there was a more than twofold significant increase (OR 2.49, 95% CI 1.02 to 6.04) in the risk of spontaneous abortion in women exposed to unscavenged anaesthetic gases for ⩾1 h per week. Veterinarians who reported performing more than five radiographic examinations per week had a statistically significant elevated risk of spontaneous abortion compared to those who performed five or less (OR 1.82, 95% CI 1.17 to 2.82). There was also approximately a twofold significant increased risk of spontaneous abortion in women who used pesticides at work (OR 1.88, 95% CI 1.18 to 3.00).

Conclusion:

Female veterinarians, particularly those of childbearing age, should be fully informed of the possible reproductive effects of unscavenged anaesthetic gases, ionising radiation and pesticide exposure and reduce their exposure by using protective devices when they are planning to become pregnant and during pregnancy.
Nectar secretion strategy in three Japanese species: changes in nectar volume and sugar concentration dependent on flower age and flowering order
Authors: Kato Shinya , Sakai Satoki
Published: April 2008

We explored how changes in nectar volume and nectar sugar concentration depend on flower age and flowering order in Gentiana triflora Pallas var. japonica (Kusnez.) Hara, Lobelia sessilifolia Lamb., and Hemerocallis middendorffii Trautv. et Mey. var. esculenta (Koidz.) Ohwi. In G. triflora var. japonica and H. middendorffii var. esculenta, change in nectar volume was small, whereas larger changes in nectar sugar concentration occurred depending on flower age. In L. sessilifolia, both the mean nectar volume and nectar sugar concentration clearly decreased with flower age. In all species, the mean nectar volume of the early-flowering group per plant was high. In terms of the change in sex allocation, the investment in male and female organs of the early-flowering group was high in G. triflora var. japonica and L. sessilifolia. We suggest that plants of G. triflora var. japonica and H. middendorffii var. esculenta secrete floral nectar for up to several days to sustain nectar volume to keep attracting pollinators while simultaneously reducing resource usage. Greater nectar secretion in the early-flowering group, in which flowers have more pollen and ovules, may contribute to greater reproductive success and may be effective for pollinators in learning the location of the plants and flowers. In addition, learning by pollinators should result in increased reproductive success of the later blooming flowers.
Basidiomycetous endophytes in New Zealand Aneuraceae (simple thalloid liverworts, Metzgeriidae) and the derived status of the monotypic genusVerdoornia
Authors: Duckett Jeffrey G. , Ligrone Roberto
Published: April 2008

The ultrastructure of endophytic basidiomycetes in two New Zealand species of Aneura and the endemic genus Verdoornia is compared with that in northern hemisphere members of the Aneuraceae. The discovery of a basidiomycete colonization in Verdoornia and a reappraisal of earlier morphological data confirms molecular evidence that this is a derived genus nested within the Aneuraceae rather than a primitive isolated taxon, as considered previously. Throughout the Aneuraceae, the basidiomycetes exhibit similar colonization patterns; initial proliferation of dikaryotic, non-clamp-forming hyphal coils within the host cells is followed by senescence and aggregation of collapsed hyphae into large masses. Multiple cycles of colonization are common. Dolipores with imperforate parenthesomes indicate that the fungi are all heterobasidiomycetes. In line with earlier cross-colonization experiments showing complete host specificity, differences in hyphal diameters and dolipore dimensions suggest that the fungi belong to different taxa. The New Zealand aneuracean fungi have multilayered walls similar to their northern hemisphere counterparts. Within the Aneuraceae there appears to be a trend from very limited or no endophyte colonization in Riccardia to colonization of the entire thallus in Cryptothallus. The cytology of the fungal associations in Aneura and Verdoornia is highly suggestive of mixotrophy.
Population size effects on germination, growth and symbiotic nitrogen fixation in an actinorhizal plant at the edge of its range
Authors: Markham John H.
Published: April 2008

Populations at the edge of their range are known to have decreased fitness. However, the factors that cause this and the specific plant characters involved are not well understood. To determine whether symbiotic interactions play a role in altering fitness, I examined population age, seed viability, and nodulation in relation to population size of Ceanothus herbaceous Raf. at the northern limit of its range. Tap roots from three populations were grown in each of the three population’s soils to examine the specificity between C. herbaceous and Frankia . Population size ranged from 14 to 7300 individuals. There was a positive exponential relationship between population size, seed germination, and the proportion of plants forming nodules in the field. Populations varied in age by 26 years and age was not related to size. Recruitment into these populations was episodic and was positively correlated to growing season temperatures. Nodulation rates in the growth experiment were similar to those in the field, and plants showed much greater growth when nodulated. Plants from the largest population showed the greatest growth when infected with Frankia from their own soil. These plants also had significantly higher nitrogen-fixing activity per total plant mass than all other plant–soil combinations, suggesting that the plants from this population show some degree of specificity to the Frankia they are normally found with. Plants from the largest population grown in soil from other populations showed lower nitrogen-fixing activity per nodule mass than any other plant–soil combination. There was a positive relationship between nodule mass allocation and plant growth, a trend not seen in other nitrogen-fixing symbioses where nodule allocation is much higher. These results illustrate the importance of considering both the regeneration and growth phases when evaluating the effects of small population size on plant performance
Shifts in morphological traits, seed production, and early establishment ofDesmodium nudiflorumfollowing prescribed fire, alone or in combination with forest canopy thinning
Authors: Huang Jianjun , Boerner Ralph E.J.
Published: April 2008

Reintroduction of periodic dormant-season fire and overstory thinning are currently being employed for forest ecosystem management in deciduous forests of eastern North America. These manipulations usually alter the flux of light and the availability of soil nutrients to the perennial herbaceous plants that dominate the understory. We utilized Bayesian statistical methods to examine the effects of prescribed burning (B) and the combination of burning and overstory thinning (T+B) on the morphology, seed production, and early establishment of Desmodium nudiflorum (L.) DC. (Fabaceae) in mixed-oak ( Quercus spp.) forests in southern Ohio. During the fourth growing season after the first fire, plants from thinned and burned (T+B) plots were 62% larger than plants from control plots (C). Both burning alone (B) and T+B treatments decreased specific leaf area (SLA). T+B also resulted in significantly decreased root mass ratio (RMR), and increased leaf mass ratio (LMR), and specific root length (SRL). During the first growing season after a second fire, both B and T+B resulted in significantly increased plant biomass, LMR, individual seed mass, and total seed production, as well as decreased SLA and plant height; in contrast, neither B nor T+B had significant impacts on leaf area ratio or seedling establishment. Prescribed fire, especially when combined with thinning, can result in increases in total biomass, seed size, and seed production, and hence enhance the fitness of this perennial herb in these mixed-oak forests.
Genetic and morphological analysis of floral homeotic mutantstepal-like bractandfagopyrum apetalaofFagopyrum esculentum
Authors: Logacheva Maria D. , Fesenko Ivan N. , Fesenko Aleksey N. , Penin Aleksey A.
Published: April 2008

The studies on floral homeotic mutants of the model plant species Arabidopsis thaliana (L.) Heynh. and Antirrhinum majus L. have clarified many important aspects of the genetic control of flower development. However, the details of this process can vary in species representing different lineages of flowering plants. The studies on floral homeotic mutants of nonmodel plant species may significantly improve the understanding of the mechanisms of morphological evolution of flowers. We report here the results of the genetic and morphological analysis of two floral homeotic mutants of common buckwheat ( Fagopyrum esculentum Moench.). The mutant, tepal-like bract (tlb), is characterized by the transformation of bracts into petaloid organs, whereas fagopyrum apetala (fap), has a carpelloid perianth. Both mutant phenotypes are caused by a single recessive nuclear mutation. The double mutant fap tlb combines the features of tlb and fap. Our results show that single gene mutations are sufficient to convert the buckwheat bract into a tepal and to confer carpel identity on first whorl organs. These results are consistent with the premise that variations on the ABC model can be used to explain a wide range of floral architectures.
Phylogenetic relationships in the tribe Alysseae (Brassicaceae) based on nuclear ribosomal ITS DNA sequences
Authors: Warwick Suzanne I. , Sauder Connie A. , Al-Shehbaz Ihsan A.
Published: April 2008

Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) region of 85 species (131 accessions) were used to determine the tribal limits, monophyly status, and phylogenetic intra-tribal relationships of genera within the tribe Alysseae (Brassicaceae). Both maximum parsimony and maximum likelihood analyses support the recognition of the tribe Alysseae s. str. (12 genera: Alyssoides , Alyssum , Aurinia , Berteroa , Bornmuellera , Clastopus , Clypeola , Degenia , Fibigia , Galitzkya , Hormathophylla , and Physoptychis ). Six well-supported clades were recognized within the Alysseae clade, including two Alyssum clades (one of which includes Clypeola ), an Alyssoides and allies clade (includes Alyssoides , Bornmuellera , Clastopus , Degenia , Fibigia , Hormathophylla , and Physoptychis ), a Berteroa and allies clade (includes Aurinia , Berteroa , and Galitzkya ), a Bornmuellera clade, and a Hormathophylla clade. Morphological and cytological support for these clades is reviewed. The ITS data support the exclusion of the following taxa from the Alysseae, with appropriate tribal assignment given in parentheses: Alyssum klimesii Al-Shehbaz (Camelineae), Asperuginoides (unresolved), Athysanus (Arabideae), Botschantzevia (Arabideae), Didymophysa (unresolved), Farsetia (Malcolmieae), Lobularia (Malcolmieae), and Ptilotrichum (Arabideae). Farsetia and Lobularia are inferred to be monophyletic, and based on molecular and morphological characters they are assigned to Malcolmieae, a recently described tribe.
Some Characteristics of Winnipeg Clay
Authors: Crawford Carl B
Published: April 2008

Compressibility and strength characteristics of specimens cut from a fairly uniform chunk sample of highly plastic Winnipeg clay are reported. A high cohesion intercept and a low friction angle in terms of effective stresses are confirmed by both undrained and special drained tests. The influence of swelling is shown to be an important factor in interpreting the natural strength in the usual working range of effective stresses.
La compression triaxiale des sols armés
Authors: Chapuis Robert P.
Published: April 2008

For a better understanding of the mechanical behaviour of reinforced soils, the paper presents a study of triaxial compression tests on soils reinforced by identical, equally spaced, plane ties. Soil–reinforcement interactions are considered by using a method similar to the one that resulted in the introduction of the cohesion effect concept in reinforced earth retaining walls. The material's limit-equilibrium equation is established for any tie orientation. These ties give to a reinforced soil a strength higher than the unreinforced soil strength. The difference may be considered as a cohesion term, which usually depends on the strength, concentration, and inclination of the ties, as well as on the radial stress level. The cohesion term given by triaxial tests is different from the cohesion effect term already introduced in reinforced earth walls, as there is no cohesion effect in a triaxial test. The paper also presents a study of adhesion conditions. By examining stress distribution in the soil between the ties, it is established that beyond a given inclination, no traction can be developed in the ties.
The behaviour of embankments on clay foundations
Authors: Tavenas F. , Leroueil S.
Published: April 2008

The present design practice for embankments on clay foundations is reviewed and its shortcomings are evidenced.A detailed analysis of field observations shows that the actual foundation behaviour differs significantly from the postulated sequence of undrained construction reponse and drained long-term consolidation. In particular a significant consolidation occurs during the very first stages of embankment construction.Design methods are reviewed and modified if necessary to account for this phenomenon. The new design approach, while largely empirical, is simpler and more reliable than existing methods.
Geology, mineralogy, and geochemistry of Canadian soft soils: a geotechnical perspective
Authors: Quigley Robert M.
Published: April 2008

A review of the recent research literature concerning the geology, mineralogy, and physicochemistry of soft soils in Canada is presented. Soft clays are considered from three viewpoints: (1) their three-dimensional distribution and chronological evolution, (2) the sedimentological processes critical in their formation, and (3) geochemistry and mineralogy as they directly influence geotechnical behaviour, especially soft soil sensitivity.Canada's soft soils are products of sedimentation in proglacial and postglacial lake basins that existed between 18 000 and 6000 years BP. They consist of both freshwater and marine clays, which usually behave quite differently, due to peptization or dispersion of the marine clays following postglacial crustal rebound that elevated all clay deposits. The evolution of the major lakes and seas is briefly reviewed in a Canada-wide context.The sedimentology review shows clearly that varved clays are normally features of bottom, heavy-density turbidity current origin, probably in very cold, ice-contact glacial lakes. Warmer postglacial lakes were probably characterized by low-density overflows, and thinly laminated clay deposits developed rather than varved clay sequences. Marine clay deposits also developed from low-density freshwater overflows followed by flocculation, organic agglomeration, and sedimentation. Modern examples are given to illustrate the three major sedimentological processes.Mineralogy and physicochemistry are reviewed in terms of their practical relevance to soft soil sensitivity. Factors influencing both the undisturbed strength and the remoulded strength are reviewed with special reference to recent Canadian research. Included are discussions of cementing agents, specific surface, amorphous and smectite contents, and zeta potential controls as they influence depositional flocculation and postdepositional peptization.
Improving the quality of input data for the wave equation analysis of driven piles
Authors: Marchetti Silvano
Published: April 2008

This note describes a velocity sensor for monitoring directly the particle velocity of driven piles during the impact. A typical velocity pulse obtained by the sensor mounted on a model pile is shown and commented upon.The sensor coupled to a peak voltage indicator forms a very simple and inexpensive system for measuring the peak pile velocity. A procedure is outlined for using the measured value of the peak pile velocity for improving the quality of the input data for the wave equation analysis.
Effect of test pit size on vibrations of footings
Authors: Sankaran K. S. , Krishnaswamy N. R. , Nair P. G. Bhaskaran
Published: April 2008

The effect of the test pit size and the backfill density on the dynamic response of footings is studied. Results of steady-state torsional field vibration tests with and without backfill on a footing kept in an excavated pit of varying lateral dimensions are presented and discussed. The influence of backfill density on the response is also investigated. It is observed that the dynamic response is practically unaffected if the lateral dimensions of the test pit are equal to or more than 2.25 times the corresponding dimensions of the footing. The resonant amplitude of rotation decreases and the resonant frequency of vibration increases with increasing backfill density.
VSA: a new fast size analysis technique for low sample weight based on Stokes' settling velocity
Authors: Syvitski J. P. M. , Swinbanks D. D.
Published: April 2008

A new technique, VSA, provides a rapid, accurate, and precise method of determining the grain-size distribution of low weight samples. Its name, VSA, stands for volume size analysis. The apparatus is inexpensive and the proposed system can analyze four samples simultaneously in 85 min when used down to 0.45 μm size. The results are provided in sedimentation diameters. A set of equations, which discretely define the increasing volume of a homogeneous sediment sample settling in an enclosed volume of water, is solved to adequately approximate the continuous distribution. The final distribution is in terms of weight percent when bulk densities of discrete settled volumes are calculated. This additional calculation has only a marginal effect on the grain-size distribution of samples having means greater than 3 μm.VSA was compared with the pipette method and found to produce "statistically identical" size distributions.
Pneumatic piezometers: multiple and single installations in vertical and inclined boreholes
Authors: Deardorff G. B. , Lumsden A. M. , Hefferon W. M.
Published: April 2008

A large-scale slope optimization program was undertaken in the Twin Buttes open-pit mine in Arizona, USA. A key element of this program was the depressurization of a fault zone, which intersects the pit wall. In order to monitor the effectiveness of the depressurization program and to establish water pressure gradients within the fault zone affected by surface and underground mining and drilling, multiple installations of up to three sealed pneumatic piezometers in one borehole were installed to depths in excess of 274 m. Special tools were devised to enable installations in angle holes from surface and underground locations. Unstable ground conditions necessitated extensive use of biodegradable drilling muds during the installation of the piezometers. The purpose of the installations and the techniques used to complete them are discussed, and opinions are offered on the effectiveness of the instruments.
ON OBSERVABILITY OF DIRAC'S STRING
Authors: NESTEROV ALEXANDER I. , DE LA CRUZ FERMÍN ACEVES
Published: April 2008

The nonrelativistic scattering of charged particles by non-quantized Dirac's monopole is explored. It is shown that the singular Dirac "string" should be observed in the quantum scattering experiment, if the Dirac quantization condition is discarded.
SOME REMARKS ON THE EINSTEIN AND MØLLER PSEUDOTENSORS FOR STATIC AND SPHERICALLY-SYMMETRIC CONFIGURATIONS
Authors: MATYJASEK JERZY
Published: April 2008

It is shown that for the spherically-symmetric and static systems the hypotheses posed by Yang and Radinschi and by Vagenas can be related to the particular distribution of the source. Simple proofs are given and a number of examples are discussed with the special emphasis put on the quantum corrected Schwarzschild black hole.
AN UNEVEN VACUUM ENERGY FLUID AS Λ, DARK MATTER, MOND AND LENS
Authors: ZHAO HONG SHENG
Published: April 2008

Various TeVeS-inspired and f(R)-inspired theories of gravity have added an interesting twist to the search for dark matter and vacuum energy, modifying the landscape of astrophysics day by day. These theories can be together called a Non-uniform Dark Energy fluid (a Nu-Lambda fluid or a VΛ fluid); a common thread of these theories, according of an up-to-date summary by HZL1, is a non-uniform vector field, describing an uneven vacuum energy fluid. The so-called "alternative" gravity theories are in fact in the standard GR gravity framework except that the cosmological "constant" is replaced by a nontrivial non-uniform vacuum energy, which couples the effects of Dark Matter and Dark Energy together by a single field. Built initially bottom-up rather than top-down as most gravity theories, TeVeS-inspired theories are healthily rooted on empirical facts. Here we attempt a review of some sanity checks of these fast-developing theories from galaxy rotation curves, solar system constraints, and gravitational lensing. We will also discuss some theoretical aspects of these theories related to the vacuum energy, and point out some analogies with electromagnetism and the Casimir effect.