Toward a standardized procedure for charcoal analysis

2020 ◽  
pp. 1-12
Author(s):  
Margarita Tsakiridou ◽  
Laura Cunningham ◽  
Mark Hardiman
Keyword(s):  
Late Glacial ◽  
Sample Volume ◽  
Charcoal Analysis ◽  
Earth System ◽  
Systematic Assessment ◽  
Chemical Treatments ◽  
Treatment Type ◽  
Organic Sediments ◽  
High Concentrations ◽  
Fossil Records

Abstract Sedimentary charcoal records are used for understanding fire as an earth system process; however, no standardized laboratory methodology exists. Varying sample volumes and chemical treatments (i.e., type of chemical for length of time) are used for the deflocculation and extraction of charcoal from sediment samples. Here, we present the first systematic assessment of the effect of commonly used chemicals on charcoal area and number of fragments. In modern charcoal the area of fragments was significantly different depending on the chemical treatment. We subsequently applied H2O2 (33%), NaClO (12.5%), and HNO3 (50%) to a late-glacial–early Holocene paleorecord and tested different sample volumes. The effects of the treatments were consistent between modern and fossil experiments, which demonstrates the validity of applying results from the modern experiment to the fossil records. Based on our experiments we suggest (1) H2O2 33%, especially for highly organic sediments; (2) avoidance of high concentrations of NaClO for prolonged periods of time, and of HNO3; and (3) samples of 1 cm3 provided typically consistent profiles. Our results indicate that charcoal properties can be influenced by treatment type and sample volume, thus emphasizing the need for a common protocol to enable reliable multi-study comparisons or composite fire histories.

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

Measurement of Plasma 1,25 Dihydroxyvitamin D Using a Novel Immunoextraction Technique and Immunoassay with Iodine Labelled Vitamin D Tracer

1997 ◽  
Vol 34 (6) ◽  
pp. 632-637 ◽  
Author(s):  
W D Fraser ◽  
B H Durham ◽  
J L Berry ◽  
E B Mawer
Keyword(s):  
Vitamin D ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Sample Volume ◽  
Cross Reactivity ◽  
Regression Equations ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
High Concentrations

We evaluated a novel assay for the measurement of 1,25 dihydroxyvitamin D (1,25 (OH)2D). Immunoextraction of 1,25 (OH)2D is performed using a mini column containing a solid-phase monoclonal antibody followed by radioimmunoassay (RIA) using an 125I-labelled 1,25 (OH)2D derivative tracer and Sac-cell separation. The mean recovery of 1,25(OH)2D3 was 101%, linearity was excellent, inter- and intra-assay coefficients of variation were 9, 8 and 13% and 11, 10 and 14% at low, medium and high concentrations of 1,25(OH)2D3, respectively. The cross-reactivity of vitamin D metabolites was <0·0015% for 25-hydroxyvitamin D3, 24, 25 dihydroxyvitamin D3 and dihydrotachysterol and 0·54% for lα calcidol. 1,25 dihydroxyvitamin D2 cross-reactivity was 79%. The detection limit of the assay was 5pmol/L. Comparison with a commercial radio receptor assay (RRA) and an in-house RIA gave regression equations of y = 0·94x+11·8 ( r = 0·98) and y = 0·91x-1·7 ( r = 0.95), respectively, with no major discrepancies between the methods in all patient groups studied. Plasma concentrations of 1,25 (OH)2D obtained with the assay were as follows: normal, unsupplemented subjects: mean 88, range 48–155 pmol/L, n = 68, patients with chronic renal failure: mean 11, range 3–36 pmol/L, n = 27, primary hyperparathyroidism: mean 198, range 130–299 pmol/L, n = 23, Paget's disease: mean 92, range 42–149 pmol/L, n = 24, osteomalacia: mean 43, range 27–61 pmol/L, n = 9. A minimum sample volume of 300 μL is required, the hands-on time is significantly less than other commercial assays and the measuring procedure is gamma counting rather than scintillation counting. The assay offers several advantages over previous methods and should allow more laboratories to offer measurement of 1,25 (OH)2D as part of their repertoire.

Late Glacial and Holocene records of tree-killing conifer bark beetles in Europe and North America: Implications for forest disturbance dynamics

The Holocene ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Nick Schafstall ◽  
Niina Kuosmanen ◽  
Christopher J Fettig ◽  
Miloš Knižek ◽  
Jennifer L Clear
Keyword(s):  
North America ◽  
Bark Beetle ◽  
Fossil Record ◽  
Bark Beetles ◽  
Late Glacial ◽  
Ips Paraconfusus ◽  
Distribution Data ◽  
Dryocoetes Confusus ◽  
Combining Data ◽  
Fossil Records

Outbreaks of conifer bark beetles in Europe and North America have increased in scale and severity in recent decades. In this study, we identify existing fossil records containing bark beetle remains from the end of the Last Glacial Maximum (~14,000 cal. yr BP) to present day using the online databases Neotoma and BugsCEP and literature searches, and compare these data with modern distribution data of selected tree-killing species. Modern-day observational data from the Global Biodiversity Information Facility (GBIF) database was used to map recorded distributions from AD 1750 to present day. A total of 53 fossil sites containing bark beetle remains, from both geological and archeological sites, were found during our searches. Fossil sites were fewer in Europe ( n = 21) than North America ( n = 32). In Europe, 29% of the samples in which remains were found were younger than 1000 cal. yr BP, while in North America, remains were mainly identified from late Glacial (~14,000–11,500 cal. yr BP) sites. In total, the fossil records contained only 8 of 20 species we consider important tree-killing bark beetles in Europe and North America based on their impacts during the last 100 years. In Europe, Ips sexdentatus was absent from the fossil record. In North America, Dendroctonus adjunctus, Dendroctonus frontalis, Dendroctonus jeffreyi, Dendroctonus pseudotsugae, Dryocoetes confusus, Ips calligraphus, Ips confusus, Ips grandicollis, Ips lecontei, Ips paraconfusus, and Scolytus ventralis were absent. Overall, preserved remains of tree-killing bark beetles are rare in the fossil record. However, by retrieving bulk material from new and existing sites and combining data from identified bark beetle remains with pollen, charcoal, tree rings, and geochemistry, the occurrence and dominance of bark beetles, their outbreaks, and other disturbance events can be reconstructed.

scholarly journals Some aspects of the last glaciation in the Mazury Lake District (north-eastern Poland)

2013 ◽  
Vol 53 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Katarzyna Pochocka-Szwarc
Keyword(s):  
Ice Sheet ◽  
Late Glacial ◽  
Climatic Changes ◽  
Lake District ◽  
Last Glaciation ◽  
North Eastern ◽  
Melt Water ◽  
History Of ◽  
Organic Sediments ◽  
Late Glacial And Holocene

ABSTRACT The morphology of the Mazury Lake District (north-eastern Poland) dates from 24-19 ka (main stadial of the youngest Vistulian glaciation). During this last glacial maximum (MIS 2) a belt with lacustrine basins was formed when the ice sheet retreated at the end of the Pomeranian phase. The ice-sheet retreat is morphologically also expressed by the occurrence of end moraines. The study area is situated in the Skaliska Basin, in the northern part of the Lake District (near the Polish/ Russian border), at the periphery of zone with end moraines. Originally the basin was an ice-dammed depression filled with melt water; the water flowed out into the developing Pregoła valley when the ice retreated and did no longer dam off the depression. The basin, which is surrounded by hill-shaped moraines, is filled now with Late Glacial and Holocene glaciolacustrine sediments. The organic sediments of the basin record the history of the Late Glacial and Holocene climatic changes in this region.

scholarly journals SUSCEPTIBILITY PROFILES TO ANTIBIOTICS IN STRAINS OF THE GENUS BACILLUS ISOLATED FROM EXTREME AQUATIC ENVIRONMENTS OF ECUADOR

2021 ◽  
pp. 27-34
Author(s):  
Marco González ◽  
Francisco Viteri ◽  
Luis Villacís ◽  
Jessica Escobar ◽  
Liliana Araujo ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Sample Volume ◽  
Diffusion Method ◽  
Bacillus Species ◽  
Natural Environments ◽  
Biochemical Tests ◽  
Volcanic Lake ◽  
Antibiotic Resistance Profile ◽  
High Concentrations ◽  
Susceptibility Profiles

Introduction. The water of aquatic ecosystems considered extreme, given the values of its physicochemical and chemical parameters, such as high concentrations of salts, oligotrophic environments, extreme pH, high radiation and extreme temperatures, there is a bacterial population that has adapted to these conditions and that they can be an important reservoir of natural resistomes. Objective. The objective of the present work was to know the profiles of susceptibility to various antibiotics in strains of the Bacillus genus isolated from mineromedicinal water spas and water from a volcanic crater lake in Ecuador. Materials and methods. A total of 16 mineromedicinal water samples and 32 samples of crater volcanic lake water were analyzed. The isolation of the Bacillus colonies was carried out by the membrane filtration technique, using Millipore filters of 0.45 μm pore, a sample volume of 100 mL and R2A agar. The isolated strains were identified following the schemes of MacFaddin (2004), complemented with the biochemical tests of the Microgen galleries for Bacillus. The antibiotic resistance profile was determined by the plate diffusion method of Kirby and Bauer (1966), interpreted according to the CLSI (2019). Results. 19 Bacillus strains were identified. Most of the strains were resistant and multi-resistant to the antibiotic clindamycin, erythromycin, gentamicin, oxacillin, and penicillin. Conclusions. The results indicate the presence of Bacillus species and resistomes associated with this genus in the water of extreme natural environments in Ecuador, which suggests that these environments may be an important reservoir of bacteria resistant to antibiotics.

A new reagent strip (Visidex) for determination of glucose in whole blood.

1983 ◽  
Vol 29 (3) ◽  
pp. 438-446 ◽  
Author(s):  
M J Sherwood ◽  
M E Warchal ◽  
S T Chen
Keyword(s):  
Whole Blood ◽  
Solid Phase ◽  
Sample Volume ◽  
Operator Technique ◽  
Good Precision ◽  
Visual Resolution ◽  
Color Development ◽  
Color Scale ◽  
High Concentrations

Abstract A new solid-phase reagent strip for determination of glucose in whole blood, Visidex, has been developed specifically for visual use in conjunction with a calibrated color scale. Two reagent pads are used, each formulated for a different portion of the range of clinical values, to maximize the visual resolution available to the user. Colorimetric examination of reacted reagent pads indicated that the label color blocks match closely the appearance of the reagent pads; that the reagent pads exhibit good precision; and that the colors of the reagent pads are independent of operator technique, sample volume (20-50 microL), and effects of potential interferents studied (although high concentrations of fluoride slightly inhibited color development). Glucose measurements obtained visually with the Visidex system correlated well with values obtained with a YSI Glucose Analyzer (for two separate studies, slope = 0.96 and 1.04, r = 0.99 and 0.96, and n = 172 and 543, respectively).

A glacial refugium and zoogeographic boundary in the Slovak eastern Carpathians

2018 ◽  
Vol 91 (1) ◽  
pp. 383-398 ◽  
Author(s):  
Lucie Juřičková ◽  
Jitka Horáčková ◽  
Anna Jansová ◽  
Jiří Kovanda ◽  
Ján Harčár ◽  
...  
Keyword(s):  
Late Glacial ◽  
Glacial Refugium ◽  
Small Scale ◽  
Snail Species ◽  
The Holocene ◽  
Eastern Carpathians ◽  
Molluscan Fauna ◽  
Fossil Records ◽  
Glacial Periods ◽  
First Time

AbstractAlthough the Carpathians in Europe have often been considered a glacial refugium for temperate plants, vertebrates, and molluscs, the fossil records, the only indisputable evidence surviving glacial periods, are as yet scarce. Moreover, the distribution of fossil records is uneven, and some areas have remained unstudied. We present here three molluscan successions from such an area—the border between the western and eastern Carpathians. This area is not only a geographic border but also a border between the oceanic and continental climate in Europe, and the molluscan fauna reflects this. We found a fluctuation of this zoogeographical border during the late glacial period and the Holocene for several snail species with their easternmost or westernmost distribution situated at this border. Such a fluctuation could reflect a small-scale shifting of climate character during the Holocene. For the first time, we recorded the fossil shells of three local endemics, Carpathica calophana, Petasina bielzi, and Perforatella dibothrion. We also found a fully developed woodland snail fauna radiocarbon dated to the Bølling period. This early occurrence of canopy forest snails indicates a possible eastern Carpathian glacial refugium for them, including local endemics, and may reflect a more moderate glacial impact on local biota than expected.

scholarly journals Late Glacial organic sediments in palaeogeographical reconstructions (cases from the Łódź region)

2015 ◽  
Vol 8 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Danuta Dzieduszyńska ◽  
Jacek Forysiak
Keyword(s):  
Environmental Changes ◽  
Riparian Forest ◽  
Younger Dryas ◽  
Late Glacial ◽  
Abiotic Conditions ◽  
Organic Sediments ◽  
Multiproxy Approach ◽  
Insight Into ◽  
Resolution Study

Abstract Late Glacial organic succession is recorded at the Żabieniec and Koźmin Las sites, in the Łódź region. A multiproxy approach provides a palaeogeographical assessment and yields a new insight into the old morainic area of the Polish Lowland. Additionally, the key profile Witów contributes in the reconstruction. It is demonstrated that the Late Glacial organic sediments of the Łódź region contain signs of environmental changes, starting from the first warming just after the Weichselian ice-sheet retreat from the Polish territory. Records at Żabieniec, apart from registering biotic and abiotic conditions which influenced functioning of a peatbog, provides information on the permafrost behaviour throughout the Late Glacial. At Koźmin Las, a unique discovery of the in situ riparian forest accompanied by organic sediments led to a high-resolution study of a series of events taking place on the floodplain during the Younger Dryas.

Radiocarbon Dating of Quaternary Loess Deposits, Banks Peninsula, Canterbury, New Zealand

1977 ◽  
Vol 7 (2) ◽  
pp. 177-196 ◽  
Author(s):  
K.M. Goh ◽  
B.P.J. Molloy ◽  
T.A. Rafter
Keyword(s):  
Organic Matter ◽  
New Zealand ◽  
Late Glacial ◽  
Radiocarbon Age ◽  
Chemical Treatments ◽  
Before And After ◽  
Loess Deposits ◽  
Physical And Chemical ◽  
Apparent Conflict

Quaternary loess deposits containing charcoal and in situ organic matter constituents from Banks Peninsula, New Zealand, were subjected to various physical and chemical treatments before radiocarbon assay. A stepwide procedure was used in which each component was radiocarbon dated before and after the treatments were applied. The criterion adopted for judging the effectiveness of a treatment is an increase in the radiocarbon age of loess layer. On this basis the oldest and therefore the most reliable date was obtained from the intra-loess charcoal and its humic acid extract. By comparison, the radiocarbon ages of organic matter constituents of the whole or partitioned loess were much younger, and are considered to represent only average ages for the particular layers concerned. No advantage was gained by dating the carbon-enriched clay-humus fraction as opposed to whole loess samples. There is an apparent conflict between our dates and current interpretation of loess stratigraphy and chronology in the South Island of New Zealand, which requires further investigation. This uncertainty apart, the upper layers of multiple loess deposits are clearly much older than earlier reports indicate, and it follows that the correlation of these deposits with late-glacial events both within and beyond New Zealand is even more tenuous and unreliable than previously thought to be the case.

scholarly journals Assessment of Soil Chemical Properties and Rice Yield in Tidal Submergence Ecosystem

2016 ◽  
Vol 18 (2) ◽  
pp. 79-87 ◽  
Author(s):  
MAA Mamun ◽  
MM Haque ◽  
QA Khaliq ◽  
MA Karim ◽  
AJMS Karim ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Rice Yield ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Soil Parameters ◽  
Yield Data ◽  
Total N ◽  
Systematic Assessment ◽  
Coefficients Of Variation ◽  
High Concentrations

Spatial variability of soil chemical properties is critical for improving rice productivity and sustainable farming techniques. However, a systematic assessment on the spatial variability of tidal ecosystem has not been conducted. So, 144 soil samples were collected across Barisal, Borguna and Jalkhati districts and analyzed for six common chemical properties. Rice yield data was obtained by surveying farmers during crop harvest. Soil parameters and rice yield varied considerably throughout the study areas and their coefficients of variation ranged from 8.77 to 71.04%. Slight variability was observed for soil organic matter (SOM) and available K. The pH of the soils was slightly acidic to alkaline. These paddy fields were characterized by high concentrations of SOM, available P, K and S; but low total N. Rice yield was significantly and positively correlated with pH, available K and S, but negatively correlated with SOM.Bangladesh Agron. J. 2015, 18(2): 79-87

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