bluuebunny/crossref_metadata_2025_split huggingface dataset:
Barriers to the recovery of aquatic insect communities in urban streams
Authors: BLAKELY TANYA J. , HARDING JON S. , MCINTOSH ANGUS R. , WINTERBOURN MICHAEL J. 
Published: July 2006

Summary1. Worldwide, increasing numbers of stream restoration projects are being initiated to rehabilitate waterways modified by urbanisation. However, many of these projects have limited success in restoring stream communities. Prompted by this, we investigated previously unrecognised barriers to aquatic insect colonisation in urban streams.2. To investigate whether the availability of suitable substrata for oviposition limited the longitudinal distribution of caddisflies, large boulders were added to the upstream reaches of one stream. Prior to the addition, more egg masses were observed downstream and this longitudinal pattern persisted subsequently.3. Malaise trapping revealed that adult caddisfly diversity and abundance was greater downstream than upstream. Furthermore, in a previous study the authors found larval caddisflies reflected the longitudinal distribution of adults.4. The only obvious potential obstructions between reaches were roads beneath which the stream flowed through culverted crossings. Malaise trapping was used to examine the effect of road culverts and bridges on caddisfly dispersal. Numbers of caddisflies caught declined upstream and about 2.5 × more individuals were taken in traps immediately below than above five culverts.4. Bridges, which had a more open structure than culverts, had no significant effect on the size of catches made above and below them.5. Road culverts could act as partial barriers to upstream flight, with consequences for larval recruitment in urban streams. We recommend that urban planners and designers of restoration projects consider possible synergistic effects of poor oviposition habitat and barriers to aquatic insect dispersal, which may be critical for the colonisation of urban headwater streams and for the maintenance of stream insect populations.
Modeling dynamics of stable carbon isotopic exchange between a boreal forest ecosystem and the atmosphere
Authors: CHEN BAOZHANG , CHEN JING M. , HUANG LIN , TANS PIETER P. 
Published: July 2006

AbstractStable isotopes of CO2 contain unique information on the biological and physical processes that exchange CO2 between terrestrial ecosystems and the atmosphere. In this study, we developed an integrated modeling system to simulate dynamics of stable carbon isotope of CO2, as well as moisture, energy, and momentum, between a boreal forest ecosystem and the atmosphere, as well as their transport/mixing processes through the convective boundary layer (CBL), using remotely sensed surface parameters to characterize the surface heterogeneity. It has the following characteristics: (i) it accounts for the influences of the CBL turbulent mixing and entrainment of the air aloft; (ii) it scales individual leaf‐level photosynthetic discrimination up to the whole canopy (Δcanopy) through the separation of sunlit and shaded leaf groups; (iii) it has the capacity to examine the detailed interrelationships among plant water‐use efficiency, isotope discrimination, and vapor pressure deficit; and (iv) it has the potential to investigate how an ecosystem discriminates against 13C at various time and spatial scales. The monthly mean isotopic signatures of ecosystem respiration (i.e. δ13CR) used for isotope flux calculation are retrieved from the nighttime flask data from the intensive campaigns (1998–2000) at 20 m level on Fraserdale tower, and the data from the growing season in 1999 are used for model validation. Both the simulated CO2 mixing ratio and δ13C of CO2 at the 20 m level agreed with the measurements well in different phases of the growing season. On a diurnal basis, the greatest photosynthetic discrimination at canopy level (i.e. Δcanopy) occurred early morning and late afternoon with a varying range of 10–26‰. The diurnal variability of Δcanopy was also associated with the phases of growing season and meteorological variables. The annual mean Δcanopy in 1999 was computed to be 19.58‰. The monthly averages of Δcanopy varied between 18.55‰ and 20.84‰ with a seasonal peak during the middle growing season. Because of the strong opposing influences of respired and photosynthetic fluxes on forest air (both CO2 and 13CO2) on both the diurnal and seasonal time scales, CO2 was consistently enriched with the heavier 13C isotope (less negative δ13C) from July to October and depleted during the remaining months, whereas on a diurnal basis, CO2 was enriched with the heavier 13C in the late afternoon and depleted in early morning. For the year 1999, the model results reveal that the boreal ecosystem in the vicinity of Fraserdale tower was a small sink with net uptake of 29.07 g 12C m−2 yr−1 and 0.34 g 13C m−2 yr−1.
Hypoandrogenaemia is associated with subclinical hypothyroidism in men
Authors: Kumar Anand , Chaturvedi P. K. , Mohanty Bidut P. 
Published: July 2006

SummaryHypothyroidism has been shown to be associated with a reduction in serum testosterone level in males. This reduction in testosterone is reversible by thyroxine replacement therapy. However, to the best of our knowledge, it is not yet known, whether a similar reduction in serum testosterone level is observed in subclinically hypothyroid males [thyroid‐stimulating hormone (TSH) < 10 mIU/L] in whom the benefits of thyroxine replacement therapy are still controversial. Our goal was to investigate the putative connections between subclinical hypothyroidism and the circulating levels of gonadotrophins and gonadal steroids in males (mean age ± SEM, 34.67 ± 1.52 years; ranging from 20 to 54 years). The serum samples from patients showing normal euthyroid and subclinical hypothyroid profiles (TSH < 10 mIU/L) were further analysed for the levels of luteinizing hormone, follicle‐stimulating hormone, prolactin, testosterone, sex hormone‐binding globulin, progesterone and oestradiol. Subclinical hypothyroidism was associated with a decrease in the levels of serum testosterone and its precursor progesterone. The data suggest that serum testosterone declines because of the non‐availability of its precursor progesterone. The level of oestradiol was similar in both the groups, suggesting a greater conversion rate of testosterone to oestradiol in subclinically hypothyroid males, in order to maintain the oestradiol levels. Prolactin levels were slightly but significantly increased in subclinical hypothyroidism. To the best of our information this is a novel report, which shows a direct association between subclinical hypothyroidism and hypoandrogenaemia. Testosterone deficiency and its symptoms should be kept in view while managing subclinical hypothyroidism in male patients. Further studies are needed in order to reveal the physiological and molecular mechanisms leading to hypoandrogenaemia in subclinical hypothyroidism (TSH < 10 mIU/L).
Movement trajectories and habitat partitioning of small mammals in logged and unlogged rain forests on Borneo
Authors: WELLS KONSTANS , PFEIFFER MARTIN , LAKIM MAKLARIN B. , KALKO ELISABETH K. V. 
Published: July 2006

Summary

Non‐volant animals in tropical rain forests differ in their ability to exploit the habitat above the forest floor and also in their response to habitat variability. It is predicted that specific movement trajectories are determined both by intrinsic factors such as ecological specialization, morphology and body size and by structural features of the surrounding habitat such as undergrowth and availability of supportive structures.
We applied spool‐and‐line tracking in order to describe movement trajectories and habitat segregation of eight species of small mammals from an assemblage of Muridae, Tupaiidae and Sciuridae in the rain forest of Borneo where we followed a total of 13 525 m path. We also analysed specific changes in the movement patterns of the small mammals in relation to habitat stratification between logged and unlogged forests. Variables related to climbing activity of the tracked species as well as the supportive structures of the vegetation and undergrowth density were measured along their tracks.
Movement patterns of the small mammals differed significantly between species. Most similarities were found in congeneric species that converged strongly in body size and morphology. All species were affected in their movement patterns by the altered forest structure in logged forests with most differences found in Leopoldamys sabanus. However, the large proportions of short step lengths found in all species for both forest types and similar path tortuosity suggest that the main movement strategies of the small mammals were not influenced by logging but comprised generally a response to the heterogeneous habitat as opposed to random movement strategies predicted for homogeneous environments.
Overall shifts in microhabitat use showed no coherent trend among species. Multivariate (principal component) analysis revealed contrasting trends for convergent species, in particular for Maxomys rajah and M. surifer as well as for Tupaia longipes and T. tana, suggesting that each species was uniquely affected in its movement trajectories by a multiple set of environmental and intrinsic features.
Collapse of Asian vulture populations: risk of mortality from residues of the veterinary drug diclofenac in carcasses of treated cattle
Authors: GREEN RHYS E. , TAGGART MARK A. , DAS DEVOJIT , PAIN DEBORAH J. , SASHI KUMAR C. , CUNNINGHAM ANDREW A. , CUTHBERT RICHARD 
Published: July 2006

Summary

The populations of three species of South Asian vultures (Gyps bengalensis, Gyps indicus and Gyps tenuirostris) have declined rapidly within the last decade and all are now critically endangered. Veterinary use of the non‐steroidal anti‐inflammatory drug diclofenac appears to be a major cause of the declines. Vultures are likely to be exposed to the drug when they feed on carcasses of livestock that were treated with diclofenac before death.
We measured the concentration of diclofenac in the tissues of treated Indian humped and European cattle (Bos indicus and Bos taurus) in relation to the interval between dosing and death. We used a dose–response model to assess the risk posed to wild vultures if they feed on carcasses of treated livestock.
Diclofenac concentrations in fat, intestine, kidney and liver were considerably higher than those in muscle, but concentrations in the first four tissues initially depleted more rapidly (half‐life 6–8 h) with time since the last injection of the drug, compared with muscle (half‐life 15 h). Depletion rates became much slower in all tissues 25–98 h after the last injection.
Diclofenac concentration, averaged across the carcass, was enough to cause appreciable mortality (> 10% of birds per meal) if oriental white‐backed vultures G. bengalensis were to take a large meal from the carcass of an animal that was given its last dose of the drug within a day or two before death. Vultures that feed selectively on tissues with high concentrations of the drug, such as kidney, liver and intestine, would be exposed to a higher risk and for longer after dosing.
Synthesis and applications. The tissues of cattle treated with diclofenac are a hazard to wild vultures that feed on an animal that dies within a few days after treatment. Intestine, kidney and liver have the highest diclofenac concentrations, but the concentration averaged across all the edible tissues of the carcass is also hazardous. Withdrawal of diclofenac from veterinary use on animals whose carcasses may become available to scavenging vultures is recommended. In ex situ and in situ conservation projects, vultures should be fed on carcasses of animals that are known not to have been treated with diclofenac in the week before death.
DNA barcoding reveals extraordinary cryptic diversity in an amphipod genus: implications for desert spring conservation
Authors: WITT JONATHAN D. S. , THRELOFF DOUG L. , HEBERT PAUL D. N. 
Published: July 2006

AbstractDNA barcoding has revealed unrecognized species in several animal groups. In this study we have employed DNA barcoding to examine Hyalella, a taxonomically difficult genus of amphipod crustaceans, from sites in the southern Great Basin of California and Nevada, USA. We assessed the extent of species diversity using a species screening threshold (SST) set at 10 times the average intrapopulation cytochrome c oxidase subunit I (COI) haplotype divergence. Despite the fact that this threshold approach is more conservative in delineating provisional species than the phylogenetic species concept, our analyses revealed extraordinary levels of cryptic diversity and endemism. The SST discriminated two provisional species within Hyalella sandra, and 33 provisional species within Hyalella azteca. COI nucleotide divergences among these provisional species ranged from 4.4% to 29.9%. These results have important implications for the conservation of life in desert springs — habitats that are threatened as a result of groundwater over‐exploitation.
Thresholds for health insurance in Rwanda: who should pay how much?
Authors: Schmidt Jean‐Olivier , Mayindo Jean K. , Kalk Andreas 
Published: July 2006

SummaryCommunity‐based health insurance schemes were introduced in Rwanda in 1999 and now cover 27% of the population. Due to widespread poverty, it remains unclear to what degree poorer population strata can be anticipated to pay into the system. This study investigates the extent to which the Rwandan population can financially contribute to obtain health insurance. More specifically, researchers explored the relationship between resource mobilization for the health system and the ability to provide community‐based health insurance across socio‐economic strata. Data from six household surveys are analysed revealing a consistent pattern: the goals of maximizing health revenue and maximizing participation in community‐based health insurance are mutually exclusive. However, the upper three quartiles of the Rwandan population are able to contribute US$1 per capita per year. In order to extend coverage to the poorest quartile, a corresponding subsidy for the coming years has to be considered.
Predictors of treatment error for children with uncomplicated malaria seen as outpatients in Blantyre district, Malawi
Authors: Osterholt Dawn M. , Rowe Alexander K. , Hamel Mary J. , Flanders William D. , Mkandala Christopher , Marum Lawrence H. , Kaimila Nyokase 
Published: July 2006

SummaryBackground  Past studies have shown that health workers in developing countries often do not follow clinical guidelines, though few studies have explored with appropriate methods why errors occur. To develop interventions that improve health worker performance, factors affecting treatment practices must be better understood.Methods  We analysed data from a health facility survey in Blantyre District, Malawi, in which health workers were observed treating ill children, and then children were independently re‐examined by ‘gold‐standard’ study clinicians. The analysis was limited to children with uncomplicated malaria (defined according to Malawi's guidelines as fever or anaemia without signs of severe illness), and a treatment error was defined as failure to treat with an effective antimalarial.Results  Twenty‐eight health workers and 349 ill‐child consultations were evaluated; 247 (70.8%) children were treated with an effective antimalarial, and 102 (29.2%) were subject to treatment error. Logistic regression analysis revealed that in‐service malaria training was not associated with treatment quality (univariate odds ratio (OR) = 1.16, 95% confidence interval (CI): 0.46–2.93); whereas acute respiratory infections training was associated with making an error (adjusted OR (aOR) = 2.42, 95% CI: 1.23–4.76). High fever and chief complaint of fever were associated with fewer errors (aOR = 0.25, 95% CI: 0.10–0.60 and aOR = 0.25, 95% CI: 0.13–0.48, respectively). Errors were more likely to occur in consultations starting before 1 p.m. (aOR = 1.88, 95% CI: 1.07–3.31). Supervision was not associated with better treatment quality.Conclusions  These results suggest that the disease‐specific training and supervision, performed before the survey, did not lead to long‐term improvements in health care quality. Furthermore, case management training for one specific disease may have worsened quality of care for another disease. These results support integration of guidelines for multiple conditions. Interventions should be evaluated for unintended negative effects on overall quality of care.
Maintenance of soil functioning following erosion of microbial diversity
Authors: Wertz Sophie , Degrange Valérie , Prosser James I. , Poly Franck , Commeaux Claire , Freitag Thomas , Guillaumaud Nadine , Roux Xavier Le 
Published: July 2006

SummaryThe paradigm that soil microbial communities, being very diverse, have high functional redundancy levels, so that erosion of microbial diversity is less important for ecosystem functioning than erosion of plant or animal diversity, is often taken for granted. However, this has only been demonstrated for decomposition/respiration functions, performed by a large proportion of the total microbial community, but not for specialized microbial groups. Here, we determined the impact of a decrease in soil microbial diversity on soil ecosystem processes using a removal approach, in which less abundant species were removed preferentially. This was achieved by inoculation of sterile soil microcosms with serial dilutions of a suspension obtained from the same non‐sterile soil and subsequent incubation, to enable recovery of community size. The sensitivity to diversity erosion was evaluated for three microbial functional groups with known contrasting taxonomic diversities (ammonia oxidizers < denitrifiers < heterotrophs). Diversity erosion within each functional group was characterized using molecular fingerprinting techniques: ribosomal intergenic spacer analysis (RISA) for the eubacterial community, denaturing gradient gel electrophoresis (DGGE) analysis ofnirKgenes for denitrifiers, and DGGE analysis of 16S rRNA genes for betaproteobacterial ammonia oxidizers. In addition, we simulated the impact of the removal approach by dilution on the number of soil bacterial species remaining in the inoculum using values of abundance distribution of bacterial species reported in the literature. The reduction of the diversity of the functional groups observed from genetic fingerprints did not impair the associated functioning of these groups, i.e. carbon mineralization, denitrification and nitrification. This was remarkable, because the amplitude of diversity erosion generated by the dilution approach was huge (level of bacterial species loss was estimated to be around 99.99% for the highest dilution). Our results demonstrate that the vast diversity of the soil microbiota makes soil ecosystem functioning largely insensitive to biodiversity erosion even for functions performed by specialized groups.
Long‐term exposure to elevated zinc concentrations induced structural changes and zinc tolerance of the nitrifying community in soil
Authors: Mertens Jelle , Springael Dirk , De Troyer Inne , Cheyns Karlien , Wattiau Pierre , Smolders Erik 
Published: July 2006

SummaryA series of long‐term Zn‐contaminated soils was sampled around a galvanized pylon. The potential nitrification rate (PNR) was unaffected by the soil total Zn concentrations up to 25 mmol Zn kg−1 whereas spiking the uncontaminated control soil with ZnCl2 to identical total concentrations completely eliminated nitrification. The larger sensitivity of the PNR to spiked ZnCl2 than to the Zn added in the field was equally found when relating the PNR to the Zn concentrations in the pore water of these soils, suggesting differences in Zn tolerance of the nitrifying communities. Zinc tolerance in the long‐term Zn‐contaminated soil was demonstrated by showing that (i) the nitrifying community of long‐term Zn‐contaminated soil samples was less sensitive to Zn than that of the uncontaminated control soil when both communities were inoculated in sterile ZnCl2‐contaminated soil samples, and, that (ii) addition of ZnCl2 to the long‐term Zn‐contaminated soil samples affected nitrification less than equal additions of ZnCl2 to uncontaminated control samples. Denaturing gradient gel electrophoresis fingerprinting of polymerase chain reaction amplified 16SrRNA gene fragments of ammonia‐oxidizing bacteria showed that the community structure in uncontaminated and long‐term contaminated soil samples was different and could be related to soil Zn concentrations.
Insect diversity in Cape fynbos and neighbouring South African vegetation
Authors: Procheş Şerban , Cowling Richard M. 
Published: July 2006

ABSTRACTAim  It has often been suggested that South Africa's Cape fynbos shrublands, although extremely rich in plant species, are poor in insects, thus representing a notable exception from the broad plant–insect diversity relationship. The aims of this study were to compare the diversity patterns of plant‐inhabiting insects in fynbos and the vegetation of three neighbouring biomes (grassland, subtropical thicket, and Nama‐karoo), and to test for a general relationship between plant diversity and insect diversity across these biomes.Location  South‐western to south‐eastern South Africa.Methods  We conducted seasonal plant surveys and sweep insect sampling in 10 × 10 m plots in the Baviaanskloof Conservation Area (Eastern Cape), where all four biomes occur. We also conducted once‐only collections in the core area of each biome.Results  Fynbos plots had insect diversity values similar to those of grassland and subtropical thicket (a dense, evergreen and spinescent shrubland with a high abundance of succulents and climbers), and significantly higher than Nama‐karoo (an open, semiarid shrubland). A remarkably strong positive relationship was found between plant and insect species richness.Main conclusions  Previous generalizations were based on a few insect groups (e.g. butterflies, under‐represented in fynbos), but ignored published results on other groups (e.g. galling insects, which are in fact over‐represented in this vegetation). We show that, overall, insect diversity in fynbos is comparable to that of neighbouring biomes. Fynbos vegetation does not represent a significant exception from the broad positive relationship between plant diversity and insect diversity.