scholarly journals Hyper-Nutrient Enrichment Status in the Sabalan Lake, Iran

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2874
Author(s):  
Roohollah Noori ◽  
Elmira Ansari ◽  
Yong-Wook Jeong ◽  
Saber Aradpour ◽  
Mohsen Maghrebi ◽  
...  
Keyword(s):  
Nutrient Enrichment ◽  
Management Practices ◽  
Storage Capacity ◽  
Limiting Factors ◽  
Molar Ratio ◽  
Anthropogenic Factors ◽  
Short Term ◽  
Reservoir Water ◽  
P Deficiency

Lakes/reservoirs are rapidly deteriorating from cultural eutrophication due to anthropogenic factors. In this study, we aimed to (1) explore nutrient levels in the Sabalan dam reservoir (SDR) of northwest Iran, (2) determine the reservoir water fertility using the total phosphorus (TP)based and total nitrogen (TN)based Carlson trophic state indices, and (3) specify primary limiting factors for the reservoir eutrophication. Our field observations showed a state of hyper-nutrient enrichment in the SDR. The highest variation of TN in the reservoir water column happened when the reservoir was severely stratified (in August) while the highest variation of TP took place when the thermocline was attenuated with the deepening of the epilimnion (in October). Both TP and TN based trophic indicators classified the SDR as a hypereutrophic lake. TN:TP molar ratio averaged at the epilimnion indicated a P–deficiency in the reservoir during warm months whilst it suggested a co–deficiency of P and N in cold months. Given the hyper-nutrient enrichment state in the reservoir, other drivers such as water residence time (WRT) can also act as the main contributor of eutrophication in the SDR. We found that WRT in the SDR varied from hundreds to thousands of days, which was much longer than that of other reservoirs/lakes with the same and even much greater storage capacity. Therefore, both hyper-nutrient enrichment and WRT mainly controlled eutrophication in the reservoir. Given time consuming and expensive management practices for reducing nutrients in the watershed, changes in the SDR operation are suggested to somewhat recover its hypereutrophic state in the short-term. However, strategic long-term recovery plans are required to reduce the transition of nutrients from the watershed to the SDR.

scholarly journals Effects of Management and Hillside Position on Soil Organic Carbon Stratification in Mediterranean Centenary Olive Grove

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Quality ◽  
Management Practices ◽  
Soil Management ◽  
Olive Grove ◽  
No Tillage ◽  
Short Term ◽  
Degradation Degree

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.

scholarly journals An Approach toward the Development of a Functional Encoding Model of Short Term Memory during Reading

1978 ◽  
Vol 10 (2) ◽  
pp. 141-148
Author(s):  
Mary Anne Herndon
Keyword(s):  
Cluster Analysis ◽  
Storage Capacity ◽  
Short Term Memory ◽  
Long Term Memory ◽  
Short Term ◽  
Processing Efficiency ◽  
Term Memory ◽  
Information Unit ◽  
Subsequent Storage

In a model of the functioning of short term memory, the encoding of information for subsequent storage in long term memory is simulated. In the encoding process, semantically equivalent paragraphs are detected for recombination into a macro information unit. This recombination process can be used to relieve the limited storage capacity constraint of short term memory and subsequently increase processing efficiency. The results of the simulation give a favorable indication of the success for the use of cluster analysis as a tool to simulate the encoding function in the detection of semantically similar paragraphs.

scholarly journals BrO/SO<sub>2</sub> molar ratios from scanning DOAS measurements in the NOVAC network

2013 ◽  
Vol 5 (2) ◽  
pp. 1845-1870 ◽  
Author(s):  
P. Lübcke ◽  
N. Bobrowski ◽  
S. Arellano ◽  
B. Galle ◽  
G. Garzón ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Optical Absorption Spectroscopy ◽  
Short Term ◽  
Dynamic Changes ◽  
Volcanic System ◽  
Molar Ratios ◽  
Remote Sensing Technique ◽  
Field Campaigns ◽  
Term Field

Abstract. The molar ratio of BrO to SO2 is, like other halogen/sulphur ratios, a~possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique Differential Optical Absorption Spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given and the influence of co-adding spectra on the retrieval error will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia encompassing almost four years of measurements between November 2009 and end of June 2013. This dataset shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

Within-Person Variability in Performance

2017 ◽  
Author(s):  
Amirali Minbashian
Keyword(s):  
Individual Differences ◽  
Management Practices ◽  
Talent Management ◽  
Employee Motivation ◽  
Individual Performance ◽  
Management Systems ◽  
Short Term ◽  
Performance Variability

Understanding individual performance at work is an important element in developing effective talent-management systems. Although research on individual performance has largely addressed between-person differences in performance, more recently, focus has been on within-person variability in performance. This chapter reviews the literature on within-person variability. A model of individual performance is presented that incorporates short-term and long-term within-person performance variability and individual differences. The benefits of the model as a framework for explaining individual performance are outlined, as are its implications for the conceptualization of talent and the development of talent-management systems. Specific talent-management practices with respect to employee assessment and employee motivation are discussed.

Identifying multiple factors limiting long-term success in environmental watering

2020 ◽  
Vol 71 (2) ◽  
pp. 238
Author(s):  
Rebecca E. Lester ◽  
Heather M. McGinness ◽  
Amina E. Price ◽  
Ashley Macqueen ◽  
N. LeRoy Poff ◽  
...  
Keyword(s):  
Limiting Factors ◽  
Migratory Fish ◽  
Short Term ◽  
Major Life ◽  
Life History Stages ◽  
Colonial Nesting ◽  
Management Actions ◽  
Ecological Objectives ◽  
Population Maintenance

Environmental watering is frequently used to achieve specific ecological objectives, such as triggering spawning or seed germination. These short-term objectives are often met, but longer-term objectives, such as population growth, may not be, especially where multiple hydrological and non-hydrological factors influence success. We propose a framework to identify these factors in space and time. Our framework steps users through identifying possible inhibiting (strictures) and supporting (promoters) factors, and placing these factors in their spatial and temporal context. This allows users to identify potential limiting factors that may require additional intervention, or render the original watering action unsustainable. We illustrate the framework with examples of a floodplain tree (black box, Eucalyptus largiflorens), colonial nesting waterbird (royal spoonbill, Platalea regia) and large-bodied migratory fish (golden perch, Macquaria ambigua). The framework explores strictures and promoters for major life-history stages, emphasising the need to support and protect all stages if objectives include population maintenance or growth. In this way, the framework can document existing mental models and can be used as the basis of a risk portfolio, a prioritisation tool or future quantitative models. Thus, the framework enables individual management actions to be better grounded in a broader context, increasing the likelihood of achieving long-term ecological objectives.

scholarly journals Pork Production with Entire Males: Directions for Control of Boar Taint

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1665 ◽  
Author(s):  
E. James Squires ◽  
Christine Bone ◽  
Jocelyn Cameron
Keyword(s):  
Management Practices ◽  
Selective Breeding ◽  
Boar Taint ◽  
Management Approach ◽  
Short Term ◽  
Pork Production ◽  
Metabolomic Profiling ◽  
Number Of Factors ◽  
Synthesis And Degradation

Boar taint is caused by the accumulation of androstenone and skatole and other indoles in the fat; this is regulated by the balance between synthesis and degradation of these compounds and can be affected by a number of factors, including environment and management practices, sexual maturity, nutrition, and genetics. Boar taint can be controlled by immunocastration, but this practice has not been accepted in some countries. Genetics offers a long-term solution to the boar taint problem via selective breeding or genome editing. A number of short-term strategies to control boar taint have been proposed, but these can have inconsistent effects and there is too much variability between breeds and individuals to implement a blanket solution for boar taint. Therefore, we propose a precision livestock management approach to developing solutions for controlling taint. This involves determining the differences in metabolic processes and the genetic variations that cause boar taint in specific groups of pigs and using this information to design custom treatments based on the cause of boar taint. Genetic, proteomic or metabolomic profiling can then be used to identify and implement effective solutions for boar taint for specific populations of animals.

Analysing water quality changes due to reservoir management and climate change for optimization of drinking water treatment

2009 ◽  
Vol 9 (1) ◽  
pp. 99-105 ◽  
Author(s):  
I. Slavik ◽  
W. Uhl
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Drinking Water ◽  
Drinking Water Treatment ◽  
Reservoir Management ◽  
Quality Changes ◽  
Short Term ◽  
Reservoir Water ◽  
Catchment Areas

Reservoir water for drinking water production may undergo major short-term and long-term quality changes. These are results of natural processes in the water body and of the water's quality entering and leaving the reservoir. Long term quality changes are due to management of catchment areas, but also to a considerable extent by external impacts like climate change. Short term quality changes are impacted by extreme events like rain storms after drought periods, which might also be a result of climate change. Furthermore, short- and mid-term quality changes are impacted by reservoir management, which also influences the ecological state of rivers downstream the reservoir. The purpose of our work is to develop a decision support tool for reservoir management which takes into account short-, mid- and long-term factors for water quality change. With the tool it is intended to simulate not only water quality, but also management impact on flood risk prevention and drinking water quality (treatment efficiency and costs) and to assist decision making for reservoir management.

Experience in assessing the dynamic state of vegetation based on a large-scale map of modern vegetation (on the example of the area “Levashovskiy les”, St. Petersburg)

2019 ◽  
pp. 39-56 ◽  
Author(s):  
E. A. Volkova ◽  
V. N. Khramtsov
Keyword(s):  
Plant Communities ◽  
Forest Fires ◽  
Vegetation Cover ◽  
Large Scale ◽  
Anthropogenic Impacts ◽  
Dynamic State ◽  
Anthropogenic Factors ◽  
Natural State ◽  
Short Term

The article is devoted to the vegetation mapping of the “Levashovskiy les”— a large forest-mire massif located in the northern part of St. Petersburg (Fig. 1). It continues a series of articles on the vegetation of existing and proposed specially protected natural areas of St. Petersburg (Volkova, Khramtsov, 2018). Large-scale map of modern vegetation (Fig. 2) is presented; the map legend includes 67 main numbers, the signs and numeric indexes at the numbers made it possible to show 93 mapping units (associations and their variants). Brief description of the main types of plant communities (spruce, pine, birch, aspen, gray alder and black alder forests; raised bogs, transitional mires and fens, floodplain and upland meadows) reveals the content of the legend. Vegetation cover is characterized by the dominance of secondary communities. The main anthropogenic impacts on modern vegetation are following: drainage reclamation, deforestation and former agricultural use, forest fires, gas pipelines, highways. Most of the forest communities are secondary ones; they have grown under the pressure of various anthropogenic factors and at different time. Nowadays an active process of natural regeneration of conife­rous (mainly spruce) trees goes in the forests. Plant community structure and species composition were taken into account as well as their dynamic state. To assess the degree of disturbance of plant communities and the potential for their restoration, the analysis of all mapped vegetation categories with respect to their position in the ranks of restorative successions was made. Then an assessment map “Dynamic state of plant communities” (Fig. 3) was compiled. The map shows following categories of dynamic types of communities: conventionally primary; relatively long-term secondary and stable long-term secondary (Sukachev, 1938; Isachenko, 1964; Karpenko, 1965; Gribova, Isachenko, 1972); short-term secondary that were divided into 3 categories representing different stages of restorative series. Present state of the vegetation cover of the “Levashovskiy les” can be determined by the ratio of the areas of conventionally primary and secondary communities. Areal analysis of dynamic categories of plant communities showed that only a bit more than 20 % of the territory is occupied by conventionally primary communities and about 60 % – by short-term secondary ones with good restorative potential. Without strong anthropogenic and natural disturbances, a significant part of the disturbed plant communities will be able to self-restore to their natural state. The establishment of a specially protected natural area as well as the regulation of conservation regime will support restoration process of nature ecosystems.

scholarly journals Lean Management Practices’ Effects on Brazilian Firms: A Quantitative and Qualitative Analysis

2021 ◽  
Vol 3 (3) ◽  
pp. 84-108
Author(s):  
Filipe Lage de Sousa ◽  
Mauricio Canêdo-Pinheiro ◽  
Bernardo Pereira Cabral ◽  
Glaucia Estefânia de Sousa Ferreira
Keyword(s):  
Management Practices ◽  
Management Practice ◽  
Cost Effective ◽  
Lean Management ◽  
Short Term ◽  
Firm Level ◽  
Basic Principles ◽  
The Impact ◽  
Innovation Outcomes

One of the key drivers for a firm's productivity growth is management. One lean management practice considered cost-effective is Kaizen. Originally from Japan, the Kaizen basic concept is continuous improvement with the involvement of the full workforce. Using a firm-level dataset from Brazil's innovation and manufacturing surveys, this paper evaluates quantitatively whether Kaizen has impacted the performance of domestic firms. Our initial results suggest a productivity premium on Kaizen adopters, yet when it materializes is not detectable in the short term. Moreover, the impact on innovation is observable after Kaizen implementation. Understanding these outcomes with a qualitative approach, our analysis highlights the importance of Kaizen on innovation, especially by improving worker's time at the production line as well as the long-term vision of Kaizen on productivity. In summary, Kaizen is not a magic wand that improves firms’ performance in a wide array of indicators yet it may boost innovation outcomes in the short term aiming to improve productivity in the long term if it is implemented carefully and persistently, as established by its basic principles.

Silicon Contamination in Diatom Nutrient Enrichment Experiments

1983 ◽  
Vol 40 (5) ◽  
pp. 657-664 ◽  
Author(s):  
Stephen J. Tarapchak ◽  
David R. Slavens ◽  
Michael A. Quigley ◽  
Judith S. Tarapchak
Keyword(s):  
Growth Rates ◽  
Nutrient Enrichment ◽  
Lake Michigan ◽  
Pyrex Glass ◽  
Short Term ◽  
Photosynthetic Rates ◽  
Nutrient Bioassay ◽  
Enrichment Experiments ◽  
Silicon Contamination

Large amounts of biologically available silicon (Si) were released into solution from the walls of Pyrex glass reagent bottles and Erlenmeyer flasks during nutrient bioassay experiments using Lake Michigan water. Photosynthetic rates in short-term (4–7 h) incubations and diatom growth rates and maximum yields in long-term incubations (~7 d) were affected by these extraneous Si supplies. The results of conventional nutrient enrichment bioassays performed in low-Si environments can be seriously biased unless Si contamination from glass incubation containers is avoided.

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