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1.
Nitrite accumulates during biological denitrification processes when carbon sources are insufficient. Acetate, methanol, and
ethanol were investigated as supplementary carbon sources in the nitrite denitrification process using biogranules. Without
supplementary external electron donors (control), the biogranules degraded 200 mg l−1 nitrite at a rate of 0.27 mg NO2–N g−1 VSS h−1. Notably, 1,500 mg l−1 acetate and 700 mg l−1 methanol or ethanol enhanced denitrification rates for 200 mg l−1 nitrite at 2.07, 1.20, and 1.60 mg NO2–N g−1 VSS h−1, respectively; these rates were significantly higher than that of the control. The sodium dodecyl sulfate polyacrylamide
gel electrophoresis of the nitrite reductase (NiR) enzyme identified three prominent bands with molecular weights of 37–41 kDa.
A linear correlation existed between incremental denitrification rates and incremental activity of the NiR enzyme. The NiR
enzyme activity was enhanced by the supplementary carbon sources, thereby increasing the nitrite denitrification rate. The
capacity of supplementary carbon source on enhancing NiR enzyme activity follows: methanol > acetate > ethanol on molar basis
or acetate > ethanol > methanol on an added weight basis. 相似文献
2.
Spectrofluorimetric Method for the Determination of Doxepin Hydrochloride in Commercial Dosage Forms
A novel spectrofluorimetric method has been developed for the determination of doxepin hydrochloride in commercial dosage
forms. The method is based on the fluorescent ion pair complex formation of the drug with eosin Y in the presence of sodium
acetate–acetic acid buffer solution of pH 4.52 which is extractable in dichloromethane. The extracted complex showed fluorescence
intensity at λem = 567 nm after excitation at 464 nm. The calibration curve was linear over the working range of 0.1–0.8 μg ml−1. Under the optimized experimental conditions, present method is validated as per International Conference on Harmonization
guidelines. The limit of detection for the developed method is 2.95 ng ml−1. The method has been successfully applied to the determination of doxepin hydrochloride in commercial dosage forms. The results
are compared with the reference spectrofluorimetric method. 相似文献
3.
Brent R. Campos Maxfield A. Fish Gardner Jones Rebecca W. Riley Peter J. Allen Peter A. Klimley Joseph J. CechJr John T. Kelly 《Environmental Biology of Fishes》2009,85(1):3-13
Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates
of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and
five female brown smoothhounds and tracked during the period of 29 June to 15 July 2004. Coarse-scale tracking consisted of
locating all tagged individuals multiple times during a single session, while fine-scale tracking consisted of following a
single individual continuously during a session. Coarse-scale tracking suggested movement toward the inner bay with incoming
and high tides and toward the outer bay with outgoing and low tides (P = 0.01), whereas the diel cycle had no apparent effect
on their movement directions. Mean shark movement rate was 0.09 m s−1 (range: 0.01–0.34 m s−1), with diel and tidal cycles both having significant effects on their rates of movement (P = 0.02 and P < 0.01), respectively. We tracked two female sharks on a fine scale over three tracking sessions in July 2004. Both individuals
exhibited higher rates of movement during the night compared to the day (P < 0.01). While one shark’s rate of movement was not significantly affected by tidal stage, the other’s was (P < 0.001). 相似文献
4.
EST-derived single nucleotide polymorphism markers for assembling genetic and physical maps of the barley genome 总被引:2,自引:0,他引:2
Kota R Varshney RK Prasad M Zhang H Stein N Graner A 《Functional & integrative genomics》2008,8(3):223-233
In a panel of seven genotypes, 437 expressed sequence tag (EST)-derived DNA fragments were sequenced. Single nucleotide polymorphisms
(SNPs) that were polymorphic between the parents of three mapping populations were mapped by heteroduplex analysis and a genome-wide
consensus map comprising 216 EST-derived SNPs and 4 InDel (insertion/deletion) markers was constructed. The average frequency of SNPs amounted to 1/130 bp and 1/107.8 bp for a set of randomly selected
and a set of mapped ESTs, respectively. The calculated nucleotide diversities (π) ranged from 0 to 40.0 × 10−3 (average 3.1 × 10−3) and 0.52 × 10−3 to 39.51 × 10–3 (average 4.37 × 10−3) for random and mapped ESTs, respectively. The polymorphism information content value for mapped SNPs ranged from 0.24 to
0.50 with an average of 0.34. As expected, combination of SNPs present in an amplicon (haplotype) exhibited a higher information
content ranging from 0.24 to 0.85 with an average of 0.50. Cleaved amplified polymorphic sequence assays (including InDels) were designed for a total of 87 (39.5%) SNP markers. The high abundance of SNPs in the barley genome provides avenues for
the systematic development of saturated genetic maps and their integration with physical maps.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Both R. Kota and R.K. Varshney contributed equally to this work. 相似文献
5.
Pharmacophore mapping studies were undertaken for a series of molecules belonging to pyrrolopyrimidines, indolopyrimidines
and their congeners as multidrug resistance-associated protein (MRP1) modulators. A five-point pharmacophore with two hydrogen
bond acceptors (A), one lipophilic/hydrophobic group (H), one positive ionic feature (P) and one aromatic ring (R) as pharmacophoric
features was developed. The pharmacophore hypothesis yielded a statistically significant 3D-QSAR model, with a correlation
coefficient of r
2 = 0.799 for training set molecules. The model generated showed excellent predictive power, with a correlation coefficient Q
2 = 0.679 for an external test set of 20 molecules. The pharmacophore was further validated using four structurally diverse
compounds with MRP1 modulatory activity. These compounds mapped well onto four of the five features of the pharmacophore.
The pharmacophore proposed here was then utilised for the successful retrieval of active molecules with diverse chemotypes
from database search. The geometry and features of pharmacophore are expected to be useful for the design of selective MRP1
inhibitors.
Figure Alignment of multidrug resistance-associated protein (MRP1) inhibitors with the developed pharmacophore.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
In order to develop a novel transdermal drug delivery system that facilitates the skin permeation of finasteride encapsulated
in novel lipid-based vesicular carriers (ethosomes)finasteride ethosomes were constructed and the morphological characteristics
were studied by transmission electron microscopy. The particle size, zeta potential and the entrapment capacity of ethosome
were also determined. In contrast to liposomes ethosomes were of more condensed vesicular structure and they were found to
be oppositely charged. Ethosomes were found to be more efficient delivery carriers with high encapsulation capacities. In vitro percutaneous permeation experiments demonstrated that the permeation of finasteride through human cadaver skin was significantly
increased when ethosomes were used. The finasteride transdermal fluxes from ethosomes containing formulation (1.34 ± 0.11 μg/cm2/h) were 7.4, 3.2 and 2.6 times higher than that of finasteride from aqueous solution, conventional liposomes and hydroethanolic
solution respectively (P < 0.01).Furthermore, ethosomes produced a significant (P < 0.01) finasteride accumulation in the skin, especially in deeper layers, for instance in dermis it reached to 18.2 ± 1.8 μg/cm2. In contrast, the accumulation of finasteride in the dermis was only 2.8 ± 1.3 μg/cm2 with liposome formulation. The study demonstrated that ethosomes are promising vesicular carriers for enhancing percutaneous
absorption of finasteride. 相似文献
7.
Staniek H Krejpcio Z Iwanik K Szymusiak H Wieczorek D 《Biological trace element research》2011,143(3):1564-1575
Chromium(III) is considered as an essential element playing a role in carbohydrate and lipid metabolism, and various chemical
forms of this element are widely used in dietary supplements. A new trinuclear chromium(III) glycinate complex [Cr3O(NH2CH2CO2)6(H2O)3]+NO3− (CrGly), an analogue of Cr3 (trinuclear Cr(III) propionate complex) has been synthesized as a potential source of supplementary
Cr. In this study, we evaluated the acute toxicity class of CrGly in Wistar rats applying the OECD 423 procedure. Male and
female Wistar rats (n = 12, 6 ♀ and 6 ♂) were given by gavage either a single dose of CrGly 2,000 mg/kg body mass (equals to 300 mg Cr(III)/kg
body mass; in aqueous solution) or equivalent volumes of distilled water and fed ad libitum commercial Labofeed B diet, and observed carefully for 14 days, then sacrificed to collect blood and internal organs for biochemical and histologic
examination. No death cases were detected. No abnormalities in animal behavior, body mass gains, gross organ histology, or
blood morphology and biochemistry were observed. The results demonstrate that LD50 of CrGly is greater than 2,000 mg/kg when administrated orally to rat; thus, this compound appears to belong to the fifth
category in the GHS system or the fourth class (“unclassified”) in the EU classification system. 相似文献
8.
Summary. Amino acids analysis in single wheat embryonic protoplast was performed using capillary electrophoresis equipped with laser-induced
fluorescence (CE-LIF), combination with tissue culture technique. Reagent fluorescein isothiocyanate (FITC) was introduced
into living protoplasts by electroporation for intracellular derivatization. A special osmotic buffer (0.6 mol/L mannitol,
5 mmol/L CaCl2) was used to keep the osmotic balance of embryonic protoplasts during the protoplasts derivatization. After completion of
the derivatization reaction in the protoplasts, a single protoplast was drawn into the capillary tip by electroosmotic flow.
Then a 0.1 M NaOH lysing solution was injected by diffusion. The derivatized amino acids were separated by capillary electrophoresis
and detected by laser-induced fluorescence detection after the protoplast was lysed Nine amino acids were quantitatively and
qualitatively determined and compared in lysate and single protoplast of wheat embryonic cells respectively, with mean concentrations
of amino acids ranging from 2.68×10−5 mol/L to 18.18×10−5 mol/L in single protoplast. 相似文献
9.
Sarah A. Cocherell Gardner J. Jones Javier B. Miranda Dennis E. Cocherell Joseph J. CechJr. Lisa C. Thompson A. Peter Klimley 《Environmental Biology of Fishes》2010,89(2):105-116
We tracked the movements of ten small (SL = 25.5–31.0 cm) and ten large (SL = 32.0–38.5 cm) radio-tagged domestic rainbow
trout (Oncorhynchus mykiss) in response to frequent pulsed releases of water in the South Fork American River (California) from July to October 2005.
In week one all the small trout moved less than 1 km upstream or downstream of their release sites. Four small trout moved
1–3 km upstream or downstream of their release sites in the following 8 weeks. Seven out of ten large trout moved downstream
after their release. In subsequent weeks most large trout showed smaller upstream and downstream movements, and were observed
between 1 km upstream and 8 km downstream of their release sites. Our results suggest that domestic rainbow trout with SL > 25 cm
are not forced downstream by daily pulsed flow increases from 5 to over 40 m3s−1. 相似文献
10.
Scaling up microbial fuel cells (MFCs) requires the development of compact reactors with multiple electrodes. A scalable single
chamber MFC (130 mL), with multiple graphite fiber brush anodes and a single air-cathode cathode chamber (27 m2/m3), was designed with a separator electrode assembly (SEA) to minimize electrode spacing. The maximum voltage produced in fed-batch
operation was 0.65 V (1,000 Ω) with a textile separator, compared to only 0.18 V with a glass fiber separator due to short-circuiting
by anode bristles through this separator with the cathode. The maximum power density was 975 mW/m2, with an overall chemical oxygen demand (COD) removal of >90% and a maximum coulombic efficiency (CE) of 53% (50 Ω resistor).
When the reactor was switched to continuous flow operation at a hydraulic retention time (HRT) of 8 h, the cell voltage was
0.21 ± 0.04 V, with a very high CE = 85%. Voltage was reduced to 0.13 ± 0.03 V at a longer HRT = 16 h due to a lower average
COD concentration, and the CE (80%) decreased slightly with increased oxygen intrusion into the reactor per amount of COD
removed. Total internal resistance was 33 Ω, with a solution resistance of 2 Ω. These results show that the SEA type MFC can
produce stable power and a high CE, making it useful for future continuous flow treatment using actual wastewaters. 相似文献
11.
Nitrifying granules cultivation in a sequencing batch reactor at a low organics-to-total nitrogen ratio in wastewater 总被引:4,自引:0,他引:4
It is possible to cultivate aerobic granular sludge at a low organic loading rate and organics-to-total nitrogen (COD/N) ratio
in wastewater in the reactor with typical geometry (height/diameter = 2.1, superficial air velocity = 6 mm/s). The noted nitrification
efficiency was very high (99%). At the highest applied ammonia load (0.3 ± 0.002 mg NH4+–N g total suspended solids (TSS)−1 day−1, COD/N = 1), the dominating oxidized form of nitrogen was nitrite. Despite a constant aeration in the reactor, denitrification
occurred in the structure of granules. Applied molecular techniques allowed the changes in the ammonia-oxidizing bacteria
(AOB) community in granular sludge to be tracked. The major factor influencing AOB number and species composition was ammonia
load. At the ammonia load of 0.3 ± 0.002 mg NH4+–N g TSS−1 day−1, a highly diverse AOB community covering bacteria belonging to both the Nitrosospira and Nitrosomonas genera accounted for ca. 40% of the total bacteria in the biomass. 相似文献
12.
Nicola D’Amelio Luca Fontanive Fulvio Uggeri Furio Suggi-Liverani Luciano Navarini 《Food biophysics》2009,4(4):321-330
Caffeine complexation by chlorogenic acid (3-caffeoylquinic acid, CAS Number [327-97-9]) in aqueous solution as well as caffeine–chlorogenate
complex in freshly prepared coffee brews have been investigated by high-resolution 1H-NMR. Caffeine and chlorogenic acid self-associations have also been studied and self-association constants have been determined
resorting to both classical isodesmic model and a recently introduced method of data analysis able to provide also the critical
aggregation concentration (cac). Furthermore, caffeine–chlorogenate association constant was measured. For the caffeine, the
average value of the self-association constant determined by isodesmic model (K
i = 7.6 ± 0.5 M−1) is in good agreement with the average value (K
a = 10 ± 1.8 M−1) determined with the method which permits the determination of the cac (8.43 ± 0.05 mM). Chlorogenic acid shows a slight
decreased tendency to aggregation with a lower average value of association constants (K
i = 2.8 ± 0.6 M−1; K
a = 3.4 ± 0.6 M−1) and a critical concentration equal to 24 ± 1 mM. The value of the association constant of the caffeine–chlorogenate complex
(30 ± 4 M−1) is compatible with previous studies and within the typical range of reported association constants for other caffeine–polyphenol
complexes. Structural features of the complex have also been investigated, and the complex conformation has been rediscussed.
Caffeine chemical shifts comparison (monomeric, complexed, coffee brews) clearly indicates a significant amount of caffeine
is complexed in beverage real system, being chlorogenate ions the main complexing agents. 相似文献
13.
Due to their unique fluorescent properties, quantum dots present a great potential for biolabelling applications; however,
the toxic interactions of quantum dots with biopolymers are little known. The toxic interactions of glutathione-capped CdTe
quantum dots with trypsin were studied in this paper using synchronous fluorescence spectroscopy, fluorescence emission spectra,
and UV–vis absorption spectra. The interaction between CdTe quantum dots and trypsin resulted in structure changes of trypsin
and inhibited trypsin's activity. Fluorescence emission spectra revealed that the quenching mechanism of trypsin by CdTe quantum
dots was a static quenching process. The binding constant and the number of binding sites at 288 and 298 K were calculated
to be 1.98 × 106 L mol−1 and 1.37, and 6.43 × 104 L mol−1 and 1.09, respectively. Hydrogen bonds and van der Waals' forces played major roles in this process. 相似文献
14.
In this study, the characteristics of extracellular polymeric substance (EPS) fractions of biofilm during the process of establishing
a partial nitrification under salt stress were analyzed in terms of concentrations, molecular weight distribution, and three-dimensional
excitation–emission matrix (EEM) fluorescence spectroscopy. A partial nitrification was formed successfully with a salinity
of 1%. Results indicated that the amount of total EPS increased from 54.2 mg g−1 VSS−1 on day 1 to 99.6 mg g−1 VSS−1 on day 55 due to the NaCl concentration changed from 0 to 10.0 g L−1 in a biofilm reactor. The changes of loosely bound EPS (LB-EPS) compounds under different salt concentrations appeared to
be more significant than those of the tightly bound EPS. A clear release of polysaccharides in the LB-EPS fraction was detected
during the enhancement of salinity. This was considered as a protective response of bacteria to the salinity. Three fluorescence
peaks were identified in the EEM fluorescence spectra of the EPS fraction samples. Two peaks were assigned to the protein-like
fluorophores, and the third peak was located at the excitation/emission wavelengths of 275 nm/425–435 nm of the spectra of
EPS fractions till the salinity maintained constant at 1%. This information is valuable for understanding the characteristics
of EPS isolated from biomass in a saline nitrogen removal system. 相似文献
15.
Greice S. Borghetti Ivana S. Lula Ruben D. Sinisterra Valquiria L. Bassani 《AAPS PharmSciTech》2009,10(1):235-242
The present study was designed to investigate the influence of operating conditions (temperature, stirring time, and excess
amount of quercetin) on the complexation of quercetin with β-cyclodextrin using a 23 factorial design. The highest aqueous solubility of quercetin was reached under the conditions 37°C/24 h/6 mM of quercetin.
The stoichiometric ratio (1:1) and the apparent stability constant (Ks = 230 M−1) of the quercetin/β-cyclodextrin complex were determined using phase-solubility diagrams. The semi-industrial production
of a 1:1 quercetin/β-cyclodextrin solid complex was carried out in aqueous solution followed by spray-drying. Although the
yield of the spray-drying process was adequate (77%), the solid complex presented low concentration of quercetin (0.14%, w/w) and, thus, low complexation efficiency. The enhancement of aqueous solubility of quercetin using this method was limited
to 4.6-fold in the presence of 15 mM of β-cyclodextrin. Subsequently, an inclusion complex was prepared via physical mixture
of quercetin with β-cyclodextrin (molar ratio of 1:1 and quercetin concentration of 23% (w/w)) and characterized using infrared spectroscopy, differential scanning calorimetry, nuclear magnetic resonance spectroscopy,
and scanning electron microscopy analyses. The enhancement of aqueous solubility of quercetin using this method was 2.2-fold,
similar to that found in the complex prepared in aqueous solution before the spray-drying process (2.5-fold at a molar ratio
of 1:1, i.e., 6 mM of quercetin and 6 mM of β-cyclodextrin). 相似文献
16.
The detailed reaction mechanism for the water-assisted hydrolysis of isocyanic acid, HNCO + (n + 1) H2O → CO2 + NH3 + nH2O (n = 0−6), taking place in the gas phase, has been investigated. All structures were optimized and characterized at the
MP2/6-31 + G* level of theory, and then re-optimized at MP2/6-311++G**. The seven explicit water molecules participating in
the hydrolysis can be divided into two groups, one directly involved in the proton relay, and the other located in the vicinity
of the substrate playing the cooperative role by engaging in hydrogen-bonding to HN = C = O. Two possible reaction pathways,
the addition of water molecule across the C = N bond or across the C = O bond, are discussed, and the former is proved to
be more favorable energetically. Our calculations suggest that, in the most kinetically favorable pathway for the titled hydrolysis,
three water molecules are directly participating in the hydrogen transfer via an eight-membered cyclic transition state, while
the other four water molecules catalyze the hydrolysis of HN = C = O by forming three eight-membered cooperative loops near
the substrate. This strain-free hydrogen-bond network leads to the best estimated rate-determining activation energy of 24.9 kJ mol−1 at 600 K, in excellent agreement with the gas-phase kinetic experimental result, 25.8 kJ mol−1. 相似文献
17.
Markus Lenz Anne Marie Enright Vincent O’Flaherty Adriaan C. van Aelst Piet N. L. Lens 《Applied microbiology and biotechnology》2009,83(2):377-388
Whole-cell immobilization of selenate-respiring Sulfurospirillum barnesii in polyacrylamide gels was investigated to allow the treatment of selenate contaminated (790 μg Se × L−1) synthetic wastewater with a high molar excess of nitrate (1,500 times) and sulfate (200 times). Gel-immobilized S. barnesii cells were used to inoculate a mesophilic (30°C) bioreactor fed with lactate as electron donor at an organic loading rate
of 5 g chemical oxygen demand (COD) × L−1 day−1. Selenate was reduced efficiently (>97%) in the nitrate and sulfate fed bioreactor, and a minimal effluent concentration
of 39 μg Se × L−1 was obtained. Scanning electron microscopy with energy dispersive X-ray (SEM–EDX) analysis revealed spherical bioprecipitates
of ≤2 μm diameter mostly on the gel surface, consisting of selenium with a minor contribution of sulfur. To validate the bioaugmentation
success under microbial competition, gel cubes with immobilized S. barnesii cells were added to an Upflow Anaerobic Sludge Bed (UASB) reactor, resulting in earlier selenate (24 hydraulic retention
times (HRTs)) and sulfate (44 HRTs) removal and higher nitrate/nitrite removal efficiencies compared to a non-bioaugmented
control reactor. S. barnesii was efficiently immobilized inside the UASB bioreactors as the selenate-reducing activity was maintained during long-term
operation (58 days), and molecular analysis showed that S. barnesii was present in both the sludge bed and the effluent. This demonstrates that gel immobilization of specialized bacterial strains
can supersede wash-out and out-competition of newly introduced strains in continuous bioaugmented systems. Eventually, proliferation
of a selenium-respiring specialist occurred in the non-bioaugmented control reactor, resulting in simultaneous nitrate and
selenate removal during a later phase of operation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Guillermo Quijano María Hernandez Frédéric Thalasso Raúl Muñoz Santiago Villaverde 《Applied microbiology and biotechnology》2009,82(5):829-836
Operation of microbial electrolysis cells (MECs) without an ion exchange membrane could help to lower the construction costs
while lowering the ohmic cell resistance and improving MEC conversion rates by minimizing the pH gradient between anode and
cathode. In this research, we demonstrate that membraneless MECs with plain graphite can be operated for methane production
without pH adjustment and that the ohmic cell resistance could be lowered with approximately 50% by removing the cation exchange
membrane. As a result, the current production increased from 66 ± 2 to 156 ± 1 A m−3 MEC by removing the membrane with an applied voltage of −0.8 V. Methane was the main energetic product despite continuous
operation under carbonate-limited and slightly acidified conditions (pH 6.1–6.2). Our results suggest that continuous production
of hydrogen in membraneless MECs will be challenging since methane production might not be avoided easily. The electrical
energy invested was not always completely recovered under the form of an energy-rich biogas; however, our results indicate
that membraneless MECs might be a viable polishing step for the treatment of the effluent of anaerobic digesters as methane
was produced under low organic loading conditions and at room temperature.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
Peter Clauwaert Schalla Mulenga Peter Aelterman Willy Verstraete 《Applied microbiology and biotechnology》2009,83(2):241-247
Using the anode effluent to compensate the alkalinization in a bio-cathode has recently been proposed as a way to operate
a microbial fuel cell (MFC) in a continuous and pH neutral way. In this research, we successfully demonstrated that the operation
of a MFC without any pH adjustments is possible by completing the liquid loop over cathode and anode. During the complete
loop operation, a stable current production of 23.2 ± 2.5 A m−3 MFC was obtained, even in the presence of 3.2–5.2 mg O2 L−1 in the anode. The use of current collectors and subdivided electrical circuitries for relative large 2.5-L-scale MFCs resulted
in ohmic cell resistances in the order of 1.4–1.7 mΩ m3 MFC, which were comparable to values of ten times smaller MFCs. Nevertheless, the bio-cathode activity still needs to be
improved significantly with a factor 10–50 in order achieve desirable current densities of 1,000 A m−3 MFC.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Dave Parrott Anthony Prickett Stéphane Pietravalle Thomas R. Etherington Mark Fletcher 《European Journal of Wildlife Research》2012,58(1):23-33
Walked spotlight transect surveys with distance sampling were used to estimate regional population densities of badger (Meles meles), fox (Vulpes vulpes) and brown hare (Lepus europaeus) in south-west England (Cornwall, Devon, Gloucestershire, Herefordshire) and Wales (Pembrokeshire, Borders, North Wales).
All regions were surveyed during spring 2006 with English regions re-surveyed in autumn 2006. In each region, surveys were
conducted in a random sample of 19.6 km2 areas (mean areas per region: spring = 19, autumn = 25). Within each survey area, a semi-random transect was established
in each of a random sample of fields (open habitat almost exclusively pasture). Transects were subsequently walked at night
with spotlights (mean transects per survey area: spring = 21, autumn = 21). Each area was surveyed twice during a season.
Total transect length per region ranged from 137 to 193 km in spring and 230 to 250 km in autumn. The mean density of species
per region was: badger 1.5–4.8 km−2, fox 1.0–4.0 km−2, hare 0.4–4.6 km−2. The study has provided baseline estimates of regional densities against which any future equivalent surveys can be compared.
It has also illustrated the practical application of large-scale walked distance sampling to surveys of British mammals. 相似文献