Species-Specific Settling Behaviors of Benthic Foraminifera: Size, Density and Structure

2021 ◽  
Vol 51 (2) ◽  
pp. 69-80
Author(s):  
Yining Chen ◽  
Yukun Shi ◽  
Silong Huang
Keyword(s):  
Settling Velocity ◽  
Specific Pattern ◽  
Sand Sample ◽  
Relative Importance ◽  
Ct Scanner ◽  
Micro Computed Tomography ◽  
Two Factors ◽  
Species Specific ◽  
Structure Patterns ◽  
Foraminiferal Test

ABSTRACT Settling velocity is a key hydrodynamic parameter to understand the transport behavior of benthic foraminiferal tests. Both size and density are fundamental in predicting settling velocity, but their relative importance is unclear. We used specimens of four benthic foraminiferal species from a carbonate-sand sample collected from Xisha Qundao, South China Sea, to investigate this question. Measurements on foraminiferal test size, shape, and density were combined with settling velocity observations using a laboratory settling tube. In addition, a micro-Computed Tomography (CT) Scanner was used to extract the internal-structure patterns of the tests of four representative specimens. Our study revealed that both size and density are important in affecting settling velocity, but the relative importance is species-specific. Size is more important than density for Amphistegina lobifera and Heterostegina depressa; these two factors are equally important for Peneroplis pertusus, but the settling velocity of Sorites orbiculus is also considerably controlled by their unique structure, besides size and density. This species-specific pattern was further compared with test development to reveal the associated biological mechanisms. As a result, a novel parameter, DT (density*TND2), is proposed as a better variable for predicting the species-specific settling behaviors.

LINE-1 distribution in six rodent genomes follow a species-specific pattern

2016 ◽  
Vol 95 (1) ◽  
pp. 21-33 ◽  
Author(s):  
A. VIEIRA-DA-SILVA ◽  
F. ADEGA ◽  
H. GUEDES-PINTO ◽  
R. CHAVES
Keyword(s):  
Specific Pattern ◽  
Species Specific

scholarly journals Age, but not short-term intensive swimming, affects chondrocyte turnover in zebrafish vertebral cartilage

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5739 ◽  
Author(s):  
Quan-Liang Jian ◽  
Wei-Chun HuangFu ◽  
Yen-Hua Lee ◽  
I-Hsuan Liu
Keyword(s):  
Critical Factor ◽  
The Body ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Short Term ◽  
Cartilage Homeostasis ◽  
Intensive Exercise ◽  
Before And After ◽  
Two Factors ◽  
Brdu Labeling

Both age and intensive exercise are generally considered critical risk factors for osteoarthritis. In this work, we intend to establish zebrafish models to assess the role of these two factors on cartilage homeostasis. We designed a swimming device for zebrafish intensive exercise. The body measurements, bone mineral density (BMD) and the histology of spinal cartilages of 4- and 12-month-old zebrafish, as well the 12-month-old zebrafish before and after a 2-week exercise were compared. Our results indicate that both age and exercise affect the body length and body weight, and the micro-computed tomography reveals that both age and exercise affect the spinal BMD. However, quantitative analysis of immunohistochemistry and histochemistry indicate that short-term intensive exercise does not affect the extracellular matrix (ECM) of spinal cartilage. On the other hand, the cartilage ECM significantly grew from 4 to 12 months of age with an increase in total chondrocytes. dUTP nick end labeling staining shows that the percentages of apoptotic cells significantly increase as the zebrafish grows, whereas the BrdU labeling shows that proliferative cells dramatically decrease from 4 to 12 months of age. A 30-day chase of BrdU labeling shows some retention of labeling in cells in 4-month-old spinal cartilage but not in cartilage from 12-month-old zebrafish. Taken together, our results suggest that zebrafish chondrocytes are actively turned over, and indicate that aging is a critical factor that alters cartilage homeostasis. Zebrafish vertebral cartilage may serve as a good model to study the maturation and homeostasis of articular cartilage.

Chloride Titration in the Dog: The Influence of Extracellular Fluid Expansion on the Pattern of Chloride Reabsorption

1973 ◽  
Vol 44 (4) ◽  
pp. 385-395 ◽  
Author(s):  
J. J. Cohen ◽  
Y. Bar-Khayim ◽  
S. Garella ◽  
J. A. Chazan
Keyword(s):  
Wide Spectrum ◽  
Extracellular Fluid ◽  
Chloride Concentration ◽  
Specific Pattern ◽  
Sodium Reabsorption ◽  
Elevated Plasma ◽  
Chloride Homeostasis ◽  
Threshold Mechanism ◽  
Two Factors ◽  
Plasma Chloride

1. The technique of chloride titration was employed in twenty dogs to determine the pattern of renal chloride handling in response to systematic increases in filtered chloride load. The influence of variations in sodium reabsorption on this pattern was also assessed by producing a wide spectrum of volume expansion during the titration protocols. 2. The results indicate that chloride reabsorption is proportional both to the rate of chloride filtration and to the rate of sodium reabsorption and, hence, that the specific pattern of each chloride titration curve is the fortuitous consequence of the interplay between these two factors. 3. The rate of chloride reabsorption relative to the simultaneous rate of sodium reabsorption was used as an index of the ability of the kidney to maintain chloride homeostasis and indicated that the kidney invariably tends to return depressed. plasma chloride concentration towards normal but, under the conditions of these acute experiments, consistently tends to reduce elevated plasma chloride concentration only when cation reabsorption is markedly depressed. 4. The present observations do not elucidate the mechanism responsible for these findings but suggest that plasma chloride concentration is not regulated through the operation of a threshold mechanism.

Morphogenetic Events in Normal and Synchronously Dividing Tetrahymena

Development ◽  
1959 ◽  
Vol 7 (2) ◽  
pp. 241-256
Author(s):  
Norman E. Williams ◽  
Otto H. Scherbaum
Keyword(s):  
Daughter Cell ◽  
Tetrahymena Pyriformis ◽  
Building Blocks ◽  
Specific Pattern ◽  
Central Position ◽  
Parent Cell ◽  
Ciliated Protozoan ◽  
Mass Cultures ◽  
Synchronous Cell ◽  
Species Specific

Synchronous cell-division has been induced in mass cultures of the small ciliated protozoan Tetrahymena pyriformis (Scherbaum & Zeuthen, 1954). While it is known that cells grow in a characteristic way during the synchronizing treatment the effect on the morphogenetic events associated with the cell cycle is not clear. Studies in ciliate morphogenesis generally have established the central position of the ciliary basal body, or kinetosome, in developmental processes. The kinetosomes are believed to be self-duplicating structures, the kinetosomal population of a daughter cell arising directly by kinetosomal reproduction in the parent cell. The species-specific pattern of the ectoplasmic cortex is largely a matter of the distribution of kinetosomes. Further, the kinetosomes appear to function either as building blocks or ‘local organizers’ in most, if not all, structural syntheses occurring in the cortex, i.e. in the production cilia, cirri, membranelles, trichocysts, and other ciliate structures (see Weisz, 1954).

scholarly journals Electrical Formation Factor of Clean Sand from Laboratory Measurements and Digital Rock Physics

2019 ◽  
Author(s):  
Mohammed Ali Garba ◽  
Stephanie Vialle ◽  
Mahyar Madadi ◽  
Boris Gurevich ◽  
Maxim Lebedev
Keyword(s):  
Rock Physics ◽  
Small Samples ◽  
Sand Sample ◽  
Laboratory Measurements ◽  
Micro Computed Tomography ◽  
Formation Factor ◽  
Digital Rock Physics ◽  
Digital Rock ◽  
Computed Tomography Images ◽  
Average Grain Size

Abstract. Electrical properties of rocks are important parameters for well-log and reservoir interpretation. Laboratory measurements of such properties are time-consuming, difficult, and are impossible in some cases. Being able to compute them from 3-D images of small samples will allow generating massive data in a short time, opening new avenues in applied and fundamental science. To become a reliable method, the accuracy of this technology needs to be tested. In this study, we developed a comprehensive and robust workflow with clean sand from two beaches. Electrical conductivities at 1 kHz were first carefully measured in the laboratory. A range of porosities spanning from a minimum of 0.26 to 0.33 to a maximum of 0.39 to 0.44, depending on the samples. Such range was achieved by compacting the samples in a way that reproduces natural packing of sand. Characteristic electrical formation factor versus porosity relationships were then obtain for each sand type. 3-D micro-computed tomography images of each sand sample from the experimental sand pack were acquired at different resolutions. Image processing was done using global thresholding method and up to 96 sub-samples of sizes from (200)3 to (700)3 voxels. After segmentation, the images were used to compute the effective electrical conductivity of the sub-cubes using a Finite Element electrostatic modelling. For the samples, a good agreement between laboratory measurements and computation from digital cores was found, if the sub-cube size REV is reached that is between (1300 μm)3 and (1820 μm)3, which, with an average grain size of 160 μm, is between 8 and 11 grains. Computed digital rock images of the clean sands have opened a way forward in getting the formation factor within a shortest possible time; laboratory calculations take five (5) to thirty-five (35) days as in the case of clean and shaly sands respectively, whereas, the digital tomography takes just three (3) to five (5) hours.

I. On the physiology of the embryonic heart (preliminary communication)

1893 ◽  
Vol 52 (315-320) ◽  
pp. 461-467 ◽  
Keyword(s):  
Embryonic Heart ◽  
Relative Importance ◽  
Two Factors ◽  
Preliminary Communication ◽  
Contractile Tissue

The object of the following experiments has been to study the effect of varying conditions on the heart previous to the development of a nervous mechanism, and thus to throw some light on the discussion as to the relative importance of the two factors in the heart’s action, viz., the contractile tissue and the nervous elements. The heart I have used is that of the chick at a period of incubation of seventy-two hours at a temperature of 38°C.

Can pay gaps between gay men and lesbians shed light on male–female pay gaps?

2019 ◽  
Vol 40 (2) ◽  
pp. 178-189
Author(s):  
Jing Wang ◽  
Morley Gunderson
Keyword(s):  
Gay Men ◽  
Gender Discrimination ◽  
Comparison Group ◽  
Wage Gap ◽  
Relative Importance ◽  
Lesbian Women ◽  
Pay Gap ◽  
Content Type ◽  
Two Factors ◽  
Shed Light

Purpose The purpose of this paper is to estimate the relative importance of gender discrimination and differences in household responsibilities as determinants of the male–female pay gap. Design/methodology/approach It parses out the relative importance of those two factors by using the pay between gay men vs lesbian women as a comparison group that should reflect only gender discrimination. Subtracting the pay gap between gay men and lesbians (reflecting only gender discrimination) from the male–female pay gap for their heterosexual counterparts (reflecting both gender discrimination and household responsibilities) provides evidence of the relative importance of gender discrimination and household responsibilities in explaining the male–female pay gap. Findings The results show that essentially all of the male–female pay gap is attributed to differences in household responsibilities. Originality/value This paper advances the literature of gender wage gap by using a novel comparison group – gay men vs lesbian women – to estimate the relative importance of gender discrimination and differences in household responsibilities as determinants of the male–female pay gap.

scholarly journals Origins and Evolutionary Patterns of the 1.688 Satellite DNA Family in Drosophila Phylogeny

2020 ◽  
Vol 10 (11) ◽  
pp. 4129-4146
Author(s):  
Leonardo G. de Lima ◽  
Stacey L. Hanlon ◽  
Jennifer L. Gerton
Keyword(s):  
Repetitive Sequences ◽  
Specific Pattern ◽  
Evolutionary Patterns ◽  
Satellite Dnas ◽  
Evolutionary Pattern ◽  
Functional Roles ◽  
Drosophila Phylogeny ◽  
Species Specific ◽  
Future Work ◽  
Eukaryotic Genomes

Satellite DNAs (satDNAs) are a ubiquitous feature of eukaryotic genomes and are usually the major components of constitutive heterochromatin. The 1.688 satDNA, also known as the 359 bp satellite, is one of the most abundant repetitive sequences in Drosophila melanogaster and has been linked to several different biological functions. We investigated the presence and evolution of the 1.688 satDNA in 16 Drosophila genomes. We find that the 1.688 satDNA family is much more ancient than previously appreciated, being shared among part of the melanogaster group that diverged from a common ancestor ∼27 Mya. We found that the 1.688 satDNA family has two major subfamilies spread throughout Drosophila phylogeny (∼360 bp and ∼190 bp). Phylogenetic analysis of ∼10,000 repeats extracted from 14 of the species revealed that the 1.688 satDNA family is present within heterochromatin and euchromatin. A high number of euchromatic repeats are gene proximal, suggesting the potential for local gene regulation. Notably, heterochromatic copies display concerted evolution and a species-specific pattern, whereas euchromatic repeats display a more typical evolutionary pattern, suggesting that chromatin domains may influence the evolution of these sequences. Overall, our data indicate the 1.688 satDNA as the most perduring satDNA family described in Drosophila phylogeny to date. Our study provides a strong foundation for future work on the functional roles of 1.688 satDNA across many Drosophila species.

Preservation potential assessment of central Atlantic biogenic carbonate deposits using X-ray micro-computed tomography (XMCT)

2020 ◽  
Author(s):  
Stergios Zarkogiannis ◽  
George Kontakiotis ◽  
Assimina Antonarakou
Keyword(s):  
Planktonic Foraminifera ◽  
Carbonate Sediments ◽  
Ct Scanner ◽  
Micro Computed Tomography ◽  
The North ◽  
Preservation Potential ◽  
Globorotalia Truncatulinoides ◽  
Mid Atlantic Ridge ◽  
Average Water ◽  
Central Atlantic

<p>Dissolution of foraminiferal calcite above the lysocline can occur within the water column, at the sediment-water interface, and/or within the sediment column as a result of low in-situ carbonate ion concentrations. The dissolution of foraminiferal shells, which are widely used for paleoceanographic studies, has the potential to influence the weight and the chemical composition of the whole test. Their partial dissolution has been suggested to significantly bias their δ<sup>18</sup>O and δ<sup>13</sup>C signals, while the trace element ratios decrease as dissolution progresses. Despite the significant Atlantic importance on the climate system, and that of the carbonate system on atmospheric CO<sub>2</sub> concentration, there have been only a few studies examining carbonate preservation along depth transects in the North and South Atlantic, and mostly by indirect means.</p><p>In order to assess the preservation potential of the central Atlantic basins, a set of 16 Atlantic surface sediment (core-top) samples along the mid-Atlantic Ridge was deployed. The samples span from approximately 30°N to 30°S and are situated along the mid-Atlantic Ridge from an average water depth of 3700 m, well above the 4200 m modern lysocline, with roughly equal bottom water ΔCO<sub>3</sub><sup>2−</sup> values (23 ±4 μmol/kg). Typically 15 pre-weighed shells of three different planktonic foraminifera species, widely used in paleoceanographic research, were picked from each sample (300-355 μm) and scanned using a GE vtomex s high-resolution micro-CT scanner. The species under consideration, namely <em>Globigerinoides ruber</em> s.s. (white), <em>Trilobatus trilobus</em> and <em>Globorotalia truncatulinoides</em>, inhabit different water depths and are known to have different geochemistries and thus preservation potentials. The preliminary analysis of the tomographs suggests that although carbonate sediments from the eastern basins below from the south equatorial upwelling zone are more corroded their initial geochemistry is not greatly altered by dissolution.</p>

scholarly journals Identification and susceptibility of clinical isolates of Candida spp. to killer toxins

2018 ◽  
Vol 78 (4) ◽  
pp. 742-749
Author(s):  
E. Robledo-Leal ◽  
L. G. Rivera-Morales ◽  
M. P. Sangorrín ◽  
G. M. González ◽  
G. Ramos-Alfano ◽  
...  
Keyword(s):  
Specific Pattern ◽  
Pcr Analysis ◽  
Its2 Region ◽  
Candida Spp ◽  
5.8S Rdna ◽  
Killer Toxins ◽  
Killer Yeasts ◽  
Invasive Infections ◽  
Pichia Kluyveri ◽  
Species Specific

Abstract Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp.

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