scholarly journals Changes of Periphyton Abundance and Biomass Driven by Factors Specific to Flooding Inflow in a River Inlet Area in Erhai Lake, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenjing Ren ◽  
Yiqian Yao ◽  
Zhonghai Zhang ◽  
Yu Cao ◽  
Changbo Yuan ◽  
...  
Keyword(s):  
Current Velocity ◽  
Field Survey ◽  
Influential Factors ◽  
Erhai Lake ◽  
Transitional Area ◽  
Periphyton Community ◽  
Assembly Mechanism ◽  
High Concentrations ◽  
Suspended Matters ◽  
Flooding Events

Periphyton is an ecological essential in freshwater lakes and rivers. Its abundance and biomass are very dynamic in various habitats and subject to various factors, for example, nutrient and light. Following flooding events, the transitional area adjacent to a river inlet and the shallow lake generates diverse habitats for periphyton with gradients in current velocity, suspended matters, nutrients, and light, which would strongly shape the growth and community of periphyton. In this study, three sampling sites were established around a river inlet in Erhai Lake, China, and a field survey was conducted in the sites from April to August (flooding seasons) in 2019 to investigate the abundance and biomass of periphyton and explore influential factors. The results showed that three study areas have different gradients of current velocity depending on the distance to the river inlet, thereby regulating the concentrations of nutrients and suspended matters, which strongly affected the periphyton community; to be specific, the biomass of periphyton was inhibited by the concentration of suspended matters and high concentrations of silicate mainly reduced the diversity of periphyton. Our results imply that the study on the driving factors of periphyton could help to understand its community assembly mechanism and biomass and species composition of periphyton can provide some reference for trophic state of the lake.

On the Mechanism and the Rate of Sub-Ground Erosion in the Loess Material

2011 ◽  
Vol 233-235 ◽  
pp. 2528-2531 ◽  
Author(s):  
Xi An Li ◽  
Qiang Xu ◽  
Hong Zhou Lin ◽  
Wan Jun Ye
Keyword(s):  
Critical Condition ◽  
Theoretical Basis ◽  
Field Survey ◽  
Influential Factors ◽  
The Other ◽  
Initial Water Content ◽  
Key Factors ◽  
Erosion Process ◽  
Initial Water ◽  
The Relationship

Sub-ground erosion often resulted in severe problems in various engineering constructions, most of which is due to the sub-erosion in loess. In this paper, the critical condition of “soil bursting” was analyzed and the formula describing the critical condition of soil bursting was derivated by the analytical method. Furthermore, the velocity of tunnel-erosion in loess and its influential factors were studied. A set of tests are designed to study the relationship between the tunnel-erosion velocity and the key influential factors. The key factors considered in the test include soil density as well as the initial water content. The other purpose is to reveal the characteristics of the tunnel-erosion process. Phenomena observed during the tests together with the data from field survey revealed the mechanism of tunneling in loess very well, and the work in this paper formed a theoretical basis for further study about sub-ground erosion in loess.

The source of nitrogen (NH4+ or NO3–) affects the concentration of oxalate in the shoots and the growth of Atriplex nummularia (oldman saltbush)

2013 ◽  
Vol 40 (10) ◽  
pp. 1057 ◽  
Author(s):  
Hussein Al Daini ◽  
Hayley C. Norman ◽  
Paul Young ◽  
Edward G. Barrett-Lennard
Keyword(s):  
Plant Growth ◽  
Nutritive Value ◽  
Field Survey ◽  
Farming Systems ◽  
Dry Mass ◽  
Calcium Deficiency ◽  
Oxalate Concentration ◽  
N Source ◽  
Atriplex Nummularia ◽  
High Concentrations

Atriplex nummularia Lindl. (oldman saltbush) is a halophytic shrub used widely as a forage for ruminant production in saline farming systems. However, it can contain high concentrations of oxalate in the leaves, which may cause calcium deficiency in grazing animals. We hypothesised that supplying NH4+ instead of NO3– to a clone of this species would decrease oxalate concentrations in the shoots, and also decrease plant growth. Oxalate concentrations were measured in plants in the field, and a glasshouse experiment was conducted in which plants were grown with 10 mM NO3– or NH4+, with 50, 200 or 500 mM NaCl. The field survey showed effects of site (P < 0.001), with average oxalate concentrations in shoots varying between 2.4 and 6.4% dry mass (DM). In the glasshouse, oxalate concentrations and plant growth were both affected by N-source and salinity (P < 0.001). Averaged across salinities, plants grown with NH4+ for 24 days had only 43% of the shoot DM but 25% of the oxalate concentration of plants grown with NO3–. We discuss the effects of N-source on oxalate concentrations, the implications of this for halophyte growth, and the opportunity to select halophytes with lower oxalate and higher nutritive value for livestock.

scholarly journals Population assessment and species distribution modeling of Paris polyphylla in Sikkim Himalaya, India

2019 ◽  
Vol 20 (5) ◽  
Author(s):  
DAWA LHENDUP LEPCHA ◽  
ADITYA PRADHAN ◽  
DHANI RAJ CHHETRI
Keyword(s):  
Species Distribution ◽  
Field Survey ◽  
Species Distribution Modeling ◽  
Influential Factors ◽  
Sikkim Himalaya ◽  
Population Assessment ◽  
Maxent Model ◽  
Distribution Modeling ◽  
Paris Polyphylla ◽  
In The Wild

Abstract. Lepcha DL, Pradhan A, Chhetri DJ. 2019. Population assessment and species distribution modeling of Paris polyphylla in Sikkim Himalaya, India. Biodiversitas 20: 1299-1305.  Paris polyphylla Smith is an important therapeutic plant that grows in the Indian Himalayan region. In Sikkim, the survival of the species is threatened by illegal extraction of its rhizome. Therefore, immediate conservation initiative is required to conserve the existing species population in the wild. Population assessment through field survey followed by ENM revealed a positive correlation between predicted suitable habitats with the actual sites of its occurrence, except in disturbed habitats. Precipitation of driest month (Bio14) and slope were the most influential factors that contributed 41.9 % and 30 % respectively to the MaxEnt model. Field survey revealed that the density of the plants varied between 0.45 (pl/m2) and 3.89 (pl/m2) and the frequency varied from 36% to 76%. The IVI for P. polyphylla ranged between 2.68 to 8.66 based on locations. On the other hand, the IVI of associated species varied from 3.57 to 18.14 based on species. P. polyphylla is a vulnerable plant in Sikkim Himalaya and it is facing an imminent threat of extinction. Under this situation, it is imperative that works on predictive modeling will help conserve the species. This study identified the potential habitats for P. polyphylla in the higher elevations of Sikkim Himalaya where it could be reintroduced.

scholarly journals ETHYLENE IN STORAGE: AN EVALUATION OF THREE INFLUENTIAL FACTORS ON TULIP BULBS' SENSITIVITY TO ETHYLENE DURING POSTHARVEST SHIPPING AND STORAGE

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 491C-491 ◽  
Author(s):  
Susan S. Liou ◽  
Chris B. Watkins ◽  
William B. Miller
Keyword(s):  
Exposure Duration ◽  
Influential Factors ◽  
Flower Bud ◽  
High Concentrations ◽  
Subsequent Storage ◽  
Tulip Bulbs ◽  
And Storage ◽  
Flower Bud Abortion ◽  
Storage Temperatures ◽  
Post Stress

During transport and the subsequent storage of tulip bulbs, inadvertent failure in ventilation and/or high contamination of Fusarium-infected bulbs may expose healthy bulbs to high concentrations of ethylene. Ethylene is known to cause many detrimental effects on forcing quality, including gummosis, increased respiration, flower bud abortion, bulb splitting and poor rooting. In this work, exposure duration and timing as well as the post-stress storage temperatures were evaluated for their potential effects on ethylene sensitivity in bulbs of four tulip cultivars. Degree of damage in sensitive cultivars `Apeldoorn' and `World's Favourite' increased with days at about 10 ppm ethylene starting at 9 and 16 days respectively. This effect strongly depended on timing of ethylene stress, as late treated bulbs showed more severe responses to ethylene treatment than early treated bulbs. Additionally, bulbs that were cooled immediately after ethylene stress, compared with those stored at 17 °C after stress, have significantly higher flowering quality in all attributes measured. This response was also strongly dependent on timing of ethylene stress and cultivar. Implications of the potential cold reversal of ethylene damage as well as effects of ethylene exposure duration and timing of stress on shipping and storage recommendations will be discussed.

scholarly journals Efficiency of date marketing system in Sistan & Bluchestan of Iran; a marketing margin approach

2010 ◽  
Vol 56 (No. 1) ◽  
pp. 43-50
Author(s):  
M. Abassian ◽  
F. Shirani Bidabadi ◽  
H. Ebrahimzadeh
Keyword(s):  
Field Survey ◽  
Wholesale Price ◽  
Marketing Channels ◽  
Influential Factors ◽  
Relative Price ◽  
Cost Calculation ◽  
Factors Affecting ◽  
Market Transparency ◽  
Marketing Costs ◽  
Economic Function

As Sistan and Blouchistan province is one of the most important date producers in Iran, an attempt is made to estimate the economic function of factors affecting the date marketing margin in the province. The data required in this research have been collected through the field survey and document analysis. The results of the estimation of marketing margin functions was obtained through utilizing of the combination of models including the Price Increase Model, Relative Price and Marketing Margin. The data analysis indicates that the farm-gate price and the harvest margin of dates are among the highly influential factors on the entire marketing margin. The retail-margin function is influenced by the retail price and the retailer cost and the wholesale margin function is affected by the wholesale price and the wholesaler cost. Calculation of the market transparency determination criteria shows that due to the fact that the total of the farm-gate price and marketing costs are less than the retail sale, there is a lack of transparency in the studied marketing channels which in turn resulted in the declining market efficiency.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

Effect of verapamil on cytoplasmic distribution of granules and microfilaments in amphibian urinary bladder

1988 ◽  
Vol 46 ◽  
pp. 324-325
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Morphological Changes ◽  
Granular Cell ◽  
Cytosolic Calcium ◽  
Calcium Storage ◽  
Amphibian Urinary Bladder ◽  
Vesicular Membrane ◽  
High Concentrations ◽  
Cytoskeletal System

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.

Hair cell changes after cationic stimulation of corti's organ

1989 ◽  
Vol 47 ◽  
pp. 798-799
Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner
Keyword(s):  
Organ Of Corti ◽  
Cross Sectional ◽  
Surface Areas ◽  
High K ◽  
Anatomical Arrangement ◽  
Cell Cytosol ◽  
High Concentrations ◽  
K Concentration ◽  
Cell Changes

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.

How to Evaluate Remote Tower Metrics in Connection With Weather Observations

2018 ◽  
Vol 8 (2) ◽  
pp. 100-111 ◽  
Author(s):  
Maik Friedrich ◽  
Christoph Möhlenbrink
Keyword(s):  
Traffic Control ◽  
Air Traffic Control ◽  
Influential Factors ◽  
Air Traffic ◽  
Weather Event ◽  
Evaluation Of Performance ◽  
Weather Events ◽  
Weather Observations ◽  
Validation Experiment ◽  
Remote Controller

Abstract. Owing to the different approaches for remote tower operation, a standardized set of indicators is needed to evaluate the technical implementations at a task performance level. One of the most influential factors for air traffic control is weather. This article describes the influence of weather metrics on remote tower operations and how to validate them against each other. Weather metrics are essential to the evaluation of different remote controller working positions. Therefore, weather metrics were identified as part of a validation at the Erfurt-Weimar Airport. Air traffic control officers observed weather events at the tower control working position and the remote control working position. The eight participating air traffic control officers answered time-synchronized questionnaires at both workplaces. The questionnaires addressed operationally relevant weather events in the aerodrome. The validation experiment targeted the air traffic control officer’s ability to categorize and judge the same weather event at different workplaces. The results show the potential of standardized indicators for the evaluation of performance and the importance of weather metrics in relation to other evaluation metrics.

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