bluuebunny/crossref_metadata_2025_split huggingface dataset:
Streamlining of plant patches in streams
Authors: SAND‐JENSEN KAJ , PEDERSEN MORTEN LAUGE 
Published: March 2008

Summary1. Plants in shallow streams often grow in well‐defined monospecific patches experiencing a predictable unidirectional flow, though of temporally variable velocity. During maximum patch development in summer we studied: (i) the shape and streamlining of 59 patches of Callitriche cophocarpa, (ii) allometric relationships between canopy size and sediment area colonized by roots (root area) and (iii) fine‐scale flow gradients for a representative patch exposed to a range of velocities to evaluate relationships between patch shape and physical impact.2. Canopy and root area viewed from above were elongated and streamlined in the flow direction, while uniform vegetative growth in all directions from a single colonizing shoot would have generated a circular form. Canopies were slightly wider in the upstream part than in the gradually tapering part downstream and the maximum height to length ratio averaged 0.25. The canopy and root area of the patches were more elongate and slender in sites with shallow water, where currents accelerate alongside patches and restrict lateral expansion, compared to deeper sites where currents can pass above the canopy. Similarly, the frontal area relative to planform area or root area was significantly lower in shallow water . Canopy shape and indices of streamlining did not change significantly with approach velocity (0.02–0.40 m s−1), either because canopy shape is not sensitive to approach velocity or summer velocities were too low to induce such changes.3. Sediment elevation within patches (avg. 4.1 cm) increased significantly with patch length, but did not differ between unstable sand or more stable coarse sediment for the same patch length. Shape of canopy and root area did not change significantly with sediment type.4. Pressure drag on the canopy as a whole is probably reduced by its rounded front, restricted height and overall slender form with a low frontal area, while the downstream overhanging canopy increases drag compared to an ideal streamlined object. Across a 100‐fold range of root areas from 0.01 to 1 m2, the frontal area of the canopy increased 29 times, planform area increased 38 times and volume increased 76 times, suggesting a trade‐off between physical impact of flow, light interception and anchoring strength.5. The canopy was compressed at high approach velocities, with low current velocity within the canopy while steep velocity gradients developed across the exposed outer surfaces as the diverted flow accelerated. Because drag processes are additive, and exist at different spatial scales and Reynolds numbers on the surface and inside of plant canopies, direct measurements on entire canopies under controlled conditions are needed to test the functional importance of their shape, size and porosity to flow.
Abundance and distribution of picoplankton in tropical, oligotrophic Lake Kivu, eastern Africa
Authors: SARMENTO HUGO , UNREIN FERNANDO , ISUMBISHO MWAPU , STENUITE STEPHANE , GASOL JOSEP M. , DESCY JEAN‐PIERRE 
Published: March 2008

Summary1. We used flow cytometry to characterize freshwater photosynthetic picoplankton (PPP) and heterotrophic bacteria (HB) in Lake Kivu, one of the East‐African great lakes. Throughout three cruises run in different seasons, covering the four major basins, phycoerythrin‐rich cells dominated the PPP. Heterotrophic bacteria and PPP cell numbers were always high and spatial variations were modest. This represents an important difference from temperate and high latitude lakes that show high fluctuations in cell abundance over an annual cycle.2. Three populations of picocyanobacteria were identified: one corresponded to single‐cells (identified as Synechococcus by epifluorescence microscopy, molecular methods and pigment content), and the two other that most probably correspond to two and four celled colonies of the same taxon. The proportion of these two subpopulations was greater under stratified conditions, with stronger nutrient limitation.3. High PPP concentrations (c. 105 cell mL−1) relative to HB (c. 106 cell mL−1) were always found. Lake Kivu supports relatively less bacteria than phytoplankton biomass than temperate systems, probably as a consequence of factors such as temperature, oligotrophy, nutrient limitation and trophic structure.4. A review of PPP concentration across aquatic systems suggests that the abundance of Synechococcus‐like cyanobacteria in large, oligotrophic, tropical lakes is very high.5. Photosynthetic picoplankton cell abundances in the oligotrophic tropical lakes Kivu and Tanganyika are comparable to those of eutrophic temperate lakes. This apparently contradicts the view that PPP abundance increases with increasing eutrophy. More data on PPP in tropical lakes are needed to explore further this particular pattern.
The morphological plastic response to water current velocity varies with age and sexual state in juvenile Atlantic salmon, Salmo salar
Authors: PÁEZ DAVID JAMES , HEDGER RICHARD , BERNATCHEZ LOUIS , DODSON JULIAN J. 
Published: March 2008

Summary1. Salmonids, like many other fish species, exhibit morphological plasticity to variations in water current velocity. However, little is known about how this response varies with age and alternative sexual tactics that usually coexist in the same area. We therefore sampled immature 1‐ and 2‐year‐old and sexually mature Salmo salar parr to determine how the morphological response to slow and rapid water currents varies across these groups.2. Both 1‐ and 2‐year‐old immature parr in rapid habitats can be distinguished from individuals in slow habitats using a combination of fin measurements. In contrast, body shape measurements were useful only to distinguish 2‐year‐old individuals in the different habitat types. We also showed that mature parr are notably robust, irrespective of habitat type. For these individuals, only their body length differed between slow and rapid water currents, being bigger in slow water currents.3. Our results imply that fins are the first structures to respond to water current velocity, followed by changes in body shape as individuals grow bigger. The robust phenotype observed for mature parr is likely to pose extra limitations on movement due to an increase in drag forces, thus contributing to their smaller size in rapid water currents.
Role of vegetation in determining carbon sequestration along ecological succession in the southeastern United States
Authors: STOY PAUL C. , KATUL GABRIEL G. , SIQUEIRA MARIO B. S. , JUANG JEHN‐YIH , NOVICK KIMBERLY A. , McCARTHY HEATHER R. , OISHI A. CHRISTOPHER , OREN RAM 
Published: March 2008

AbstractVegetation plays a central role in controlling terrestrial carbon (C) exchange, but quantifying its impacts on C cycling on time scales of ecological succession is hindered by a lack of long‐term observations. The net ecosystem exchange of carbon (NEE) was measured for several years in adjacent ecosystems that represent distinct phases of ecological succession in the southeastern USA. The experiment was designed to isolate the role of vegetation – apart from climate and soils – in controlling biosphere–atmosphere fluxes of CO2 and water vapor. NEE was near zero over 5 years at an early successional old‐field ecosystem (OF). However, mean annual NEE was nearly equal, approximately −450 g C m−2 yr−1, at an early successional planted pine forest (PP) and a late successional hardwood forest (HW) due to the sensitivity of the former to drought and ice storm damage. We hypothesize that these observations can be explained by the relationships between gross ecosystem productivity (GEP), ecosystem respiration (RE) and canopy conductance, and long‐term shifts in ecosystem physiology in response to climate to maintain near‐constant ecosystem‐level water‐use efficiency (EWUE). Data support our hypotheses, but future research should examine if GEP and RE are causally related or merely controlled by similar drivers. At successional time scales, GEP and RE observations generally followed predictions from E. P. Odum's ‘Strategy of Ecosystem Development’, with the surprising exception that the relationship between GEP and RE resulted in large NEE at the late successional HW. A practical consequence of this research suggests that plantation forestry may confer no net benefit over the conservation of mature forests for C sequestration.
Extinction vulnerability of tropical montane endemism from warming and upslope displacement: a preliminary appraisal for the highest massif in Madagascar
Authors: RAXWORTHY CHRISTOPHER J. , PEARSON RICHARD G. , RABIBISOA NIRHY , RAKOTONDRAZAFY ANDRY M. , RAMANAMANJATO JEAN‐BAPTISTE , RASELIMANANA ACHILLE P. , WU SHENGHAI , NUSSBAUM RONALD A. , STONE DÁITHÍ A. 
Published: March 2008

AbstractOne of the predicted biological responses to climate warming is the upslope displacement of species distributions. In the tropics, because montane assemblages frequently include local endemics that are distributed close to summits, these species may be especially vulnerable to experiencing complete habitat loss from warming. However, there is currently a dearth of information available for tropical regions. Here, we present a preliminary appraisal of this extinction threat using the herpetological assemblage of the Tsaratanana Massif in northern Madagascar (the island's highest massif), which is rich with montane endemism. We present meteorological evidence (individual and combined regional weather station data and reanalysis forecast data) for recent warming in Madagascar, and show that this trend is consistent with recent climate model simulations. Using standard moist adiabatic lapse rates, these observed meteorological warming trends in northern Madagascar predict upslope species displacement of 17–74 m per decade between 1993 and 2003. Over this same period, we also report preliminary data supporting a trend for upslope distribution movements, based on two surveys we completed at Tsaratanana. For 30 species, representing five families of reptiles and amphibians, we found overall mean shifts in elevational midpoint of 19–51 m upslope (mean lower elevation limit 29–114 m; mean upper elevation limit −8 to 53 m). We also found upslope trends in mean and median elevational observations in seven and six of nine species analysed. Phenological differences between these surveys do not appear to be substantial, but these upslope shifts are consistent with the predictions based on meteorological warming. An elevational range displacement analysis projects complete habitat loss for three species below the 2 °C ‘dangerous’ warming threshold. One of these species is not contracting its distribution, but the other two were not resampled in 2003. A preliminary review of the other massifs in Madagascar indicates potential similar vulnerability to habitat loss and upslope extinction. Consequently, we urgently recommend additional elevational surveys for these and other tropical montane assemblages, which should also include, when possible, the monitoring of local meteorological conditions and habitat change.
Rates of orchiopexies in Sweden: 1977–1991
Authors: Richiardi L. , Vizzini L. , Nordenskjöld A. , Pettersson A. , Akre O. 
Published: March 2008

SummaryCryptorchidism is a known risk factor for testicular cancer and the secular increase in testicular cancer incidence might have been paralleled by a similar increase in cryptorchidism. Data on trends in prevalence of cryptorchidism are however conflicting and decreases have recently been reported. To analyse Swedish trends in rates of orchiopexy, we used the Swedish Hospital Discharge Register to identify all cases of orchiopexy carried out for cryptorchidism between 1977 and 1991, that is, before the era of outpatient orchiopexies in Sweden. Observed trends were analysed in 5‐year age groups. The estimated average annual per cent changes (EAPCs) and the years in which the EAPC significantly changed were estimated using Joinpoint Regression. Finally, we estimated the cumulative incidence of orchiopexy by birth cohort. Among boys aged less than 10, the orchiopexy rate started to decrease in the early 1980s. EAPCs were −2.88 (95% confidence interval (CI): −5.48, −0.21) among boys aged 5–9 and −6.63 among those aged 0–4 (95% CI: −8.84, −4.37). Among subjects aged at least 10, the rate decreased over the whole study period. Although the use of orchiopexy rates to measure prevalence of cryptorchidism has limitations, our findings may suggest that cryptorchidism prevalence decreased in Sweden starting from the early 1980s.
Expression and arrangement of extracellular matrix proteins in the lungs of mice infected with Paracoccidioides brasiliensis conidia
Authors: González Angel , Lenzi Henrique Leonel , Motta Ester Maria , Caputo Luzia , Restrepo Angela , Cano Luz Elena 
Published: March 2008

SummaryExtracellular matrix (ECM) proteins are important modulators of migration, differentiation and proliferation for the various cell types present in the lungs; they influence the immune response as well as participate in the adherence of several fungi including Paracoccidioides brasiliensis. The expression, deposition and arrangement of ECM proteins such as laminin, fibronectin, fibrinogen, collagen and proteoglycans in the lungs of mice infected with P. brasiliensis conidia has been evaluated in this study, together with the elastic fibre system. Lungs of BALB/c mice infected with P. brasiliensis conidia were analysed for the different ECM proteins by histological and immunohistochemical procedures at different times of infection. In addition, laser scanning confocal microscopy and scanning electron microscopy were used. During the early periods, the lungs of infected animals showed an inflammatory infiltrate composed mainly of polymorphonuclear neutrophils (PMNs) and macrophages, while during the later periods, mice presented a chronic inflammatory response with granuloma formation. Re‐arrangement and increased expression of all ECM proteins tested were observed throughout all studied periods, especially during the occurrence of inflammatory infiltration and formation of the granuloma. The elastic fibre system showed an elastolysis process in all experiments. In conclusion, this study provides new details of pulmonary ECM distribution during the course of paracoccidioidomycosis.
Enhanced proliferation of aortal smooth muscle cells treated by 1,25(OH)2D3in vitro coincides with impaired formation of elastic fibres
Authors: Tukaj Cecylia 
Published: March 2008

SummaryElastin is the major extracellular matrix component synthesized, secreted and deposited by vascular smooth muscle cells (SMCs) in the arterial media and thus plays an important role in vascular homeostasis. Results of our previous studies showed that 1α,25‐dihydroxycholecalciferol [1,25(OH)2D3‐calcitriol] accelerates proliferation of SMCs and modulates their growth in vitro. The aim of this study was to find ultrastructural support for the idea that 1,25(OH)2D3‐calcitriol affects elastic fibre formation due to accelerated proliferation of aortal SMCs in vitro. SMCs exposed 10 days to supraphysiological concentration (10 nM) of calcitriol in primary culture were examined by fluorescence and transmission electron microscopy. Morphological studies revealed that calcitriol altered elastin maturation by favouring accumulation of immature rather than fully processed elastic fibres. A substantial decrease in the amorphous elastin deposition and abnormal accumulation of microfibrillar component, in thickened multilayer culture, were observed. These studies suggest that 1,25(OH)2D3 affect formation of elastic fibres due to enhanced proliferation of SMCs in culture.
A SURVEY OF THE RESULTS OF ROUTINE BACTERIOLOGICAL TESTS OF PASTEURISED MILK
Authors: MCKENZIE D. A. , BOOTH C. E. 
Published: March 2008

SummaryThe survey indicates that seasonal variations in the proportion of failing samples is greater with the 1/2 hr. methylene blue than with the colony count test. The incidence of thermoduric organisms in the raw milk will no longer be important since such bacteria have little effect on the methylene blue test, but there will be a greater need for adequate cooling, efficient cold storage and avoidance of post‐pasteurisation contamination. Plate count and coliform tests will, however, still be useful in the dairy laboratory.The methylene blue results for samples stored at atmospheric temperature or at 18° C. show good agreement. It is not known whether the agreement would be equally as good in very cold weather, as the results presented here do not cover such conditions.A small percentage of samples (1.7%) which by previous standards would have been regarded as highly satisfactory may fail the dye test; in addition, approximately 5.0% of samples showing high coliform contamination may satisfy the new standard.
ROPY CONTAMINATION IN PASTEURIZED MILK
Authors: Murray J. G. 
Published: March 2008

SummaryAn outbreak of ropy milk in bottled pastuerized milk was traced to Bact. aerogenes types I and IT and possibly Alkaligenes species gaining access through the filler bowl from some of the washed milk bottles. Most of the bottles were of low count by the standard rinse technique, but the majority were capable of producing rope when filled with sterile milk. The standard rinse technique seems inadequate for the detection of this kind of contamination.
A STATISTICAL EXAMINATION OF CONDUCTIVITY VALUES FOR ASEPTICALLY DRAWN MILK SUPPLIES
Authors: Jones G. Elis 
Published: March 2008

Summary1. The electrical conductivity of quarter milk samples was compared with a number of indirect tests.2. The differences between the conductivities of four quarters of an udder were assessed by deducting the lowest value recorded from the other three values. (degrees above normal, D.A.N.)
THE EFFECT OF OVERNIGHT REFRIGERATION ON THE RESULTS OF THE BACTERIOLOGICAL EXAMINATION OF FARM WATER SUPPLIES
Authors: JONES G. ELIS , FRANKLIN PATRICIA M. , THOMAS S. B. 
Published: March 2008

Summary:About 20% of water samples examined 20 hr. after sampling, this period including 18 hr. storage at 3–5°, had coli‐aerogenes and Bact. coli contents significantly lower than those determined after 2 hr. at air temperature. Samples with over 50 such organisms/100 ml. at the earlier testing time seldom showed an increased content after refrigeration overnight. The results of statistical analysis of the data confirmed the findings of other workers that coli‐aerogenes bacteria are less abundant in samples of water stored before analysis. Colony counts at 37° and 22° did not reflect this reduction in numbers.
THE EXPERIMENTAL EVALUATION OF ANTI‐T.B. DRUGS
Authors: CROSHAW BETTY 
Published: March 2008

Summary:Some of the chief methods used in the screening of new compounds against tuberculosis are briefly reviewed. Streptomycin, p‐aminosalicylic acid, p‐acetamidobenzaldehyde thiosemicarbazone, p‐ethylsulphonylbenzaldehyde thiosemicarbazone and p‐anisaldehyde thiosemicarbazone have been tested against mice infected intracerebrally and the results compared with those obtained using the ordinary guinea‐pig test. All were active in mice and all except p‐anisaldehyde thiosemicarbazone in guinea‐pigs. A suitable strain of mice is essential and a Table is given showing the susceptibility of several strains to tubercle bacilli inoculated intracerebrally.
THE SURVIVAL OF BACTERIA IN HIGH‐FREQUENCY ELECTRIC FIELDS
Authors: JACOBS S. E. , THORNLEY MARGARET J. , MAURICE P. 
Published: March 2008

Summary:Various bacteria, but principally Bact. coli and Staph. aureus, have been exposed in glass containers to high‐frequency electric fields at frequencies of 1–65 Mc./s., the electrodes being external. Various periods and intensities of treatment were tried, but in no case was a lethal temperature allowed to develop. There was no evidence that any mortality was caused by the treatments, even when voltage stresses high enough to induce rapid heat development in poorly conducting treatment fluids were used.
BACTERIOLOGICAL ASPECTS OF IN‐BOTTLE PASTEURIZATION OF MILK, WITH A SIMPLE METHOD OF ASSESSING THE HEATING EQUIVALENT
Authors: CLEGG L. F. L. , LOMAX KATHLEEN L. 
Published: March 2008

Summary:In collaboration with the National Physical Laboratory temperature distribution in an in‐bottle pasteurization plant was studied by means of thermocouples, and the coolest point in the coolest bottles located. A simple method is given for assessing the heat‐treatment in comparison with orthodox holder pasteurization. The results of bacteriological and phosphatase activity tests of in‐bottle pasteurized milk compared very favourably with those of the holder and H.T.S.T. processes. The safety margin is similar to that of the holder process and the efficiency of destruction of tubercle bacilli in milk has been calculated to be over 100%. The heating curve follows a straight line on inverted semi‐logarithmic paper, and linear relationships are shown to exist between the ‘slope’of this line, the maximum milk temperature reached in the coolest part of the coolest bottles and the heating equivalent. It is suggested that the process can be controlled by knowing this maximum temperature.
THE USE OF CALCIUM ALGINATE WOOL FOR SWABBING DAIRY EQUIPMENT
Authors: TREDINNICK J. E. , TUCKER J. 
Published: March 2008

Summary:Seventy‐three comparative tests of dairy plant were made using swabs of ribbon gauze and calcium alginate wool, the latter being dissolved before plating in dilute sodium hexametaphosphate solution. The colony counts obtained with alginate swabs were in the great majority of cases much higher than those with gauze. When both types of swab were inoculated with known numbers of Bact. coli, the recovery was again much greater with alginate wool.
NOTES ON THE BIOLOGY OF AZOTOBACTER
Authors: JENSEN H. L. 
Published: March 2008

Summary:Forty strains of A. chroococcum from Danish soils showed a rather uniform power of nitrogen fixation in mannitol solution where the mean gain of nitrogen after 12 days corresponded to 17.1 mg./g. of mannitol, with a standard deviation of ±9.1%. In agreement with the statement of Fischer (1949) the strains could be divided into two groups with different rates of nitrogen fixation. Ten strains fixed in 3 days less than 30% and 30 strains from 45 to 100% of the final amount of nitrogen after 12 days, which was almost the same in both groups. In glucose medium a rapid nitrogen fixation was shown by some of the strains that grew slowly with mannitol. Strains which fixed rapidly with mannitol did so with glucose also.Ten strains of A. beijerinckii grew slowly with glucose as well as mannitol, and two strains apparently failed to utilize the latter compound.In media sterilized by autoclaving, the gain of nitrogen was approximately one‐third higher with mannitol than with glucose, owing to deterioration of the glucose on heating. When glucose and mannitol were sterilized by filtration, the difference in nitrogen fixation corresponded closely to the difference in heat of combustion of the two compounds.Some strains of both A. chroococcum and A. beijerinkii could grow on nitrogen‐free agar containing sodium benzoate as the sole source of carbon, while others could not.