Phytoplankton–zooplankton relationships based on phytoplankton functional groups in two tropical reservoirs

2019 ◽  
Vol 70 (5) ◽  
pp. 721 ◽  
Author(s):  
Anamaria S. Diniz ◽  
Juliana S. Severiano ◽  
Mauro Melo Júnior ◽  
Ênio W. Dantas ◽  
Ariadne N. Moura
Keyword(s):  
Functional Groups ◽  
Subsurface Layer ◽  
Group Iv ◽  
Transparent Plastic ◽  
Group Iii ◽  
In Situ Experiments ◽  
Phytoplankton Functional Groups ◽  
Negative Growth ◽  
Phytoplankton Morphology

The aim of this study was to evaluate the phytoplankton–zooplankton interaction, using phytoplankton morphology-based functional groups, in two reservoirs that have different trophic state indices (TSIs). We hypothesised that the herbivorous relationships of zooplankton with the phytoplankton community would differ between reservoirs with different TSIs. In order to test this hypothesis, field collections to study the phytoplankton, zooplankton and abiotic variables were undertaken between July 2016 and April 2017 from the subsurface layer and in situ experiments were conducted using biomanipulation of the micro- and mesozooplankton. In situ experiments consisted of 18 microcosms in 5-L transparent plastic bottles (in triplicate). The mesotrophic reservoir showed predominance of chlorophytes (Group IV) and mesozooplankton during the study period. In the presence of zooplankton, all phytoplankton groups showed negative growth rates and higher ingestion values, mainly Group IV. In the supereutrophic reservoir, ingestion rates showed that micro- and mesozooplankton reduced the biomass of colonial (Group VII) and filamentous (Group III) cyanobacteria respectively. The findings of the present study reveal that Copepoda Calanoida, as well as small cladocerans, may be the most suitable zooplankton groups for biomass biomanipulation of different morphofunctional phytoplankton groups in mesotrophic reservoirs, and for the control of cyanobacteria in supereutrophic reservoirs.

Nitrogen-fixing communities in an intertidal ecosystem

1978 ◽  
Vol 24 (8) ◽  
pp. 932-938 ◽  
Author(s):  
B. Ben Bohlool ◽  
William J. Wiebe
Keyword(s):  
Nitrogen Fixation ◽  
Photosynthetic Bacteria ◽  
Statistical Significance ◽  
Group Iv ◽  
Group Iii ◽  
Group I ◽  
Mud Flat ◽  
Intertidal Ecosystem ◽  
The Mean

Nitrogen fixation (acetylene reduction) associated with various communities in the intertidal sand and mud flat was measured in situ. Areas which were colonized by algae, plants, and animals generally had significantly higher activities than areas which were visibly uncolonized. The highest activities were measured at sites colonized by a mixed bloom of Oscillatoria–Euglena–photosynthetic bacteria. These areas occupied only about 1% of the surface of the sediments, yet contributed nearly 50% of the biologically fixed nitrogen. Enteromorpha communities also exhibited relatively high activities. Sites were grouped according to the statistical significance of the mean of their activities: group I: uncolonized sand, mud and gravel flats, Eelgrass (Zostera) communities, and snail (Amphibola) beds, with an estimated contribution of 1 g N ha−1 day−1; group II: Cockel (Chione) beds, 3g N ha−1 day−1; group III: Salicornia, Ulva, Juncus, and Enteromorpha, 10 g N ha−1 day−1; and group IV: Oscillatoria–Euglena–photosynthetic bacteria association, 200 g N ha−1 day−1. Enteromorpha and Oscillatoria–Euglena–photosynthetic bacteria communities showed significantly lower rates of nitrogen fixation in the dark than in the light.

Characterization of GaAs and Ge Films on (100) Silicon

1987 ◽  
Vol 91 ◽  
Author(s):  
J.-M. Baribeau ◽  
D.C. Houghton ◽  
P. MaignÉ ◽  
W.T. Moore ◽  
R.L.S. Devine ◽  
...  
Keyword(s):  
Surface Preparation ◽  
Group Iv ◽  
Ex Situ ◽  
Rapid Thermal Anneal ◽  
Defect Reduction ◽  
Group Iii ◽  
Superlattice Dislocation ◽  
Strained Layer Superlattice

ABSTRACTA UHV MBE apparatus in which the deposition of both group IV and group III-V components is possible without breaking vacuum has been utilized to compare the growth of GaAs epilayers on non-polar Si(100) and Ge coated Si(100) substrates. In addition, a comparison of GaAs epilayers grown on substrates cleaned by ex-situ techniques and on substrates given all UHV in-situ surface preparation was made. Defect reduction by the incorporation of strained-layer superlattice dislocation filters and by post-growth rapid thermal anneal (RTA) thermal cycles was also investigated. Optical and material properties comparable to MBE grown GaAs/GaAs were obtained for GaAs grown on Ge coated Si(100) substrates.

Squamous endometrial neoplasia—are Fluhmann's postulates still relevant?

1995 ◽  
Vol 5 (6) ◽  
pp. 421-425 ◽  
Author(s):  
J. C. Dalrymple ◽  
P. Russell
Keyword(s):  
Group Iv ◽  
Fourth Group ◽  
Group Iii ◽  
Anatomical Variants ◽  
Group I ◽  
Similar Disease ◽  
Group Ii

A review of squamous neoplasia of the endometrium (in situand/or invasive) with or without coexistent similar disease of the cervix, revealed four anatomical variants in 22 patients. The patterns were: Group (i), endometrial squamous neoplasia only; Group (ii), discontiguous endometrial and cervical squamous neoplasia; Group (iii), possibly discontiguous endometrial and squamous neoplasia; and Group (iv), contiguous endometrial and squamous disease. The details of the histology, management and outcome are discussed, the latter being much poorer for the fourth group. The criteria for diagnosing squamous neoplasia involving the endometrium are re-examined and a recommendation for these criteria is suggested.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

A computer-control program for TEM in situ fatigue experiments

1989 ◽  
Vol 47 ◽  
pp. 620-621
Author(s):  
Kenneth S. Vecchio ◽  
John A. Hunt
Keyword(s):  
Slow Crack Growth ◽  
Computer Control ◽  
Control Program ◽  
Video Tape ◽  
Computer Control System ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Tremendous Amount ◽  
And Control

In-situ experiments conducted within a transmission electron microscope provide the operator a unique opportunity to directly observe microstructural phenomena, such as phase transformations and dislocation-precipitate interactions, “as they happen”. However, in-situ experiments usually require a tremendous amount of experimental preparation beforehand, as well as, during the actual experiment. In most cases the researcher must operate and control several pieces of equipment simultaneously. For example, in in-situ deformation experiments, the researcher may have to not only operate the TEM, but also control the straining holder and possibly some recording system such as a video tape machine. When it comes to in-situ fatigue deformation, the experiments became even more complicated with having to control numerous loading cycles while following the slow crack growth. In this paper we will describe a new method for conducting in-situ fatigue experiments using a camputer-controlled tensile straining holder.The tensile straining holder used with computer-control system was manufactured by Philips for the Philips 300 series microscopes. It was necessary to modify the specimen stage area of this holder to work in the Philips 400 series microscopes because the distance between the optic axis and holder airlock is different than in the Philips 300 series microscopes. However, the program and interfacing can easily be modified to work with any goniometer type straining holder which uses a penrmanent magnet motor.

Reductive Cleavage of Secondary Sulfonamides: Converting Terminal Functional Groups into Versatile Synthetic Handles

2019 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Kevin M. Maloney
Keyword(s):  
Functional Groups ◽  
Late Stage ◽  
Reductive Cleavage ◽  
Bioactive Molecules ◽  
General Method

Sulfonamides are pervasive in drugs and agrochemicals, yet are typically considered as terminal functional groups rather than synthetic handles. To enable the general late-stage functionalization of secondary sulfonamides, we have developed a mild and general method to reductively cleave the N-S bonds of sulfonamides to generate sulfinates and amines, components which can further react <i>in-situ</i> to access a variety of other medicinally relevant functional groups. The utility of this platform is highlighted by the selective manipulation of several complex bioactive molecules.

Coliform transport in a pristine reservoir: modeling and field studies

1998 ◽  
Vol 37 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Elisa Garvey ◽  
John E. Tobiason ◽  
Michael Hayes ◽  
Evelyn Wolfram ◽  
David A. Reckhow ◽  
...  
Keyword(s):  
Model Development ◽  
Fate And Transport ◽  
Field Studies ◽  
Meteorological Conditions ◽  
Reservoir Modeling ◽  
Vertical Circulation ◽  
Quality Model ◽  
Circulation Patterns ◽  
In Situ Experiments

This paper reports on field studies and model development aimed at understanding coliform fate and transport in the Quabbin Reservoir, an oligotrophic drinking water supply reservoir. An investigation of reservoir currents suggested the importance of wind driven phenomena, and that both lateral and vertical circulation patterns exist. In-situ experiments of coliform decay suggested dependence on light intensity and yielded an appropriate decay coefficient to be used in CE-QUAL-W2, a two-dimensional hydrodynamic and water quality model. Modeling confirmed the sensitivity of reservoir outlet concentration to vertical variability within the reservoir, meteorological conditions, and location of coliform source.

scholarly journals Upscaling THM modeling from small-scale to full-scale in-situ experiments in the Callovo-Oxfordian claystone

2021 ◽  
Vol 144 ◽  
pp. 104582
Author(s):  
D.M. Seyedi ◽  
C. Plúa ◽  
M. Vitel ◽  
G. Armand ◽  
J. Rutqvist ◽  
...  
Keyword(s):  
Full Scale ◽  
Small Scale ◽  
In Situ Experiments

Analysis of surface conditioning methods on core-veneer bond strength of CAD/CAM zirconia restorations

2020 ◽  
pp. 1-11
Author(s):  
Anip K. Roy ◽  
Govind N. Prasad ◽  
Tushar V. Bhagat ◽  
Saurabh Chaturvedi ◽  
Vishwanath Gurumurthy ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Group Iv ◽  
Control Group ◽  
Group Iii ◽  
Surface Conditioning ◽  
Group I ◽  
Alumina Particles ◽  
Scanning Electron

BACKGROUND: The increased strength of zirconia has resulted in its widespread application in clinical dentistry. Nevertheless, the fracture of veneering porcelains remains one of the key reasons of failure. OBJECTIVE: The objective of this study was to compare and analyze the influence of surface conditioning methods on the core-veneer bond strength of zirconia restorations. METHODS: Thirty specimens of zirconia core with sizes 10 × 5 × 5 mm were layered with porcelain of sizes 5 × 3 × 3 mm. On the basis of different surface conditioning methods, four groups were made: Group I: abrasion with airborne alumina particles of 110 μm size, Group II: sandblasting with silica coated alumina particles of 50 μm in size, Group III (modified group): alteration with a coating of zirconia powder prior to sintering, and Group IV (control group): metal core specimens. The shear force of all specimens was tested using a universal testing machine with a 0.5 mm/min crosshead speed. One-way analysis of variance (ANOVA) and Tukey’s post hoc pair wise comparison (p= 0.05) were performed to analyze the shear bond strength. A scanning electron microscope was used to assess the fractured specimens. RESULTS: A statistically significant difference was noted between the groups. The mean value of shear bond strength was 40.25 MPa for Group I, 41.93 MPa for Group II, 48.08 MPa for Group III and 47.01 MPa for Group IV. CONCLUSIONS: The modified zirconia group and control group demonstrated a significantly higher mean bond strength than that of Group I, where airborne particle abrasion was used. The scanning electron microscope showed that cohesive fracture in the porcelain veneers was the main problem of failure in altered zirconia. The modified zirconia specimens in Group III demonstrated significantly improved values of shear bond strength.

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