scholarly journals Density Dependence Influences the Efficacy of Wastewater Remediation by Lemna minor

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1366
Author(s):  
Éamonn Walsh ◽  
Neil E. Coughlan ◽  
Seán O’Brien ◽  
Marcel A. K. Jansen ◽  
Holger Kuehnhold
Keyword(s):  
Surface Coverage ◽  
Production Systems ◽  
Lemna Minor ◽  
High Density ◽  
Wastewater Remediation ◽  
Nutrient Assimilation ◽  
Negative Effect ◽  
Growing Conditions ◽  
Possible Cause ◽  
Media Volume

As part of a circular economy (CE) approach to food production systems, Lemnaceae, i.e., duckweed species, can be used to remediate wastewater due to rapid nutrient assimilation and tolerance of non-optimal growing conditions. Further, given rapid growth rates and high protein content, duckweed species are a valuable biomass. An important consideration for duckweed-mediated remediation is the density at which the plants grow on the surface of the wastewater, i.e., how much of the surface of the medium they cover. Higher duckweed density is known to have a negative effect on duckweed growth, which has implications for the development of duckweed-based remediation systems. In the present study, the effects of density (10–80% plant surface coverage) on Lemna minor growth, chlorophyll fluorescence and nutrient remediation of synthetic dairy processing wastewater were assessed in stationary (100 mL) and re-circulating non-axenic (11.7 L) remediation systems. Overall, L. minor growth, and TN and TP removal rates decreased as density increased. However, in the stationary system, absolute TN and TP removal were greater at higher densities (50–80% coverage). The exact cause of density related growth reduction in duckweed is unclear, especially at densities well below 100% surface coverage. A further experiment comparing duckweed grown at ‘low’ and ‘high’ density conditions with the same biomass and media volume conditions, showed that photosynthetic yield, Y(II), is reduced at high density despite the same nutrient availability at both densities, and arguably similar shading. The results demonstrate a negative effect of high density on duckweed growth and nutrient uptake, and point towards signals from neighbouring duckweed colonies as the possible cause.

Do older workers really reduce firm productivity?

2018 ◽  
Vol 29 (4) ◽  
pp. 521-542 ◽  
Author(s):  
Bokwon Lee ◽  
Joowoong Park ◽  
Jae-Suk Yang
Keyword(s):  
Older Workers ◽  
Value Added ◽  
Manufacturing Firms ◽  
Future Research ◽  
Organisational Performance ◽  
Jel Codes ◽  
Positive Effects ◽  
Financial Conditions ◽  
Negative Effect ◽  
Growing Conditions

In this article, we examine the effect of workforce ageing on company productivity, using an analysis based on Korean firms. We found that an increase in the ratio of workers aged over 50 years to total workers had a negative effect on value added per worker, which was consistent with the findings of most previous studies based on European data. However, the results of the analysis, including various classifications such as size, industry and several financial conditions, revealed that an increase in the ratio of older workers had positive effects on value added per worker in large manufacturing firms under risky or growing conditions. As the productivity of older workers may vary, future research may determine under what conditions – size, industry, region and financial conditions – older workers contribute positively to productivity. Firms with financial troubles or those planning to downsize should be cautious about laying off older workers as an approach to improving organisational performance because these workers contribute positively to productivity under certain conditions. JEL Codes: J24, J54, N3

Comparison of foraging behaviour of small, urban-sensitive insectivores in continuous woodland and woodland remnants in a suburban landscape

2006 ◽  
Vol 33 (7) ◽  
pp. 591 ◽  
Author(s):  
P. Hodgson ◽  
K. French ◽  
R. E. Major
Keyword(s):  
Foraging Behaviour ◽  
Urban Landscape ◽  
High Density ◽  
Native Vegetation ◽  
Urban Landscapes ◽  
Insectivorous Birds ◽  
Behavioural Changes ◽  
Remnant Vegetation ◽  
Negative Effect ◽  
High Density Housing

Small patches of remnant vegetation are often considered to have low conservation value. In urban landscapes their value may potentially be higher than in other landscapes because they can be the only representatives of original native vegetation. Despite this potential, many small insectivorous birds that rely on native vegetation demonstrate sensitivities within urban landscapes through reduced numbers or total absence. One reason for this sensitivity may be that remnants are of suboptimal quality, which may be reflected in behavioural changes. Using five insectivorous species that were present (in low numbers) in remnants surrounded by high-density housing, foraging behaviour was examined in relation to vegetation. The proportion of time birds spent on different foraging substrates and plant species was compared with that of conspecifics in continuous vegetation. Canopy and shrub foragers showed minimal behavioural changes. Ground foragers in remnants tended to forage at lower heights than those in continuous vegetation; however, these changes did not appear to reflect a negative effect. These changes were partially explained by structural differences between vegetation in remnants and continuous sites. The number of times a bird attacked prey items was significantly higher in continuous habitat for only two species. Overall, the foraging behaviour of small insectivorous birds in remnants surrounded by high-density housing was not adversely affected by urbanisation and it appears that remnants have potential value as habitat and foraging sources in an urban landscape. Despite this, small insectivores are still sensitive to urbanisation, suggesting that other factors, probably in the matrix, are important.

scholarly journals Plant adaptation to climate change—opportunities and priorities in breeding

2012 ◽  
Vol 63 (3) ◽  
pp. 251 ◽  
Author(s):  
Scott C. Chapman ◽  
Sukumar Chakraborty ◽  
M. Fernanda Dreccer ◽  
S. Mark Howden
Keyword(s):  
Climate Change ◽  
Elevated Co2 ◽  
Abiotic Stresses ◽  
Production Systems ◽  
Pests And Diseases ◽  
Co2 Concentrations ◽  
New Varieties ◽  
Growing Conditions ◽  
Management Changes

Climate change in Australia is expected to influence crop growing conditions through direct increases in elevated carbon dioxide (CO2) and average temperature, and through increases in the variability of climate, with potential to increase the occurrence of abiotic stresses such as heat, drought, waterlogging, and salinity. Associated effects of climate change and higher CO2 concentrations include impacts on the water-use efficiency of dryland and irrigated crop production, and potential effects on biosecurity, production, and quality of product via impacts on endemic and introduced pests and diseases, and tolerance to these challenges. Direct adaptation to these changes can occur through changes in crop, farm, and value-chain management and via economically driven, geographic shifts where different production systems operate. Within specific crops, a longer term adaptation is the breeding of new varieties that have an improved performance in ‘future’ growing conditions compared with existing varieties. In crops, breeding is an appropriate adaptation response where it complements management changes, or when the required management changes are too expensive or impractical. Breeding requires the assessment of genetic diversity for adaptation, and the selection and recombining of genetic resources into new varieties for production systems for projected future climate and atmospheric conditions. As in the past, an essential priority entering into a ‘climate-changed’ era will be breeding for resistance or tolerance to the effects of existing and new pests and diseases. Hence, research on the potential incidence and intensity of biotic stresses, and the opportunities for breeding solutions, is essential to prioritise investment, as the consequences could be catastrophic. The values of breeding activities to adapt to the five major abiotic effects of climate change (heat, drought, waterlogging, salinity, and elevated CO2) are more difficult to rank, and vary with species and production area, with impacts on both yield and quality of product. Although there is a high likelihood of future increases in atmospheric CO2 concentrations and temperatures across Australia, there is uncertainty about the direction and magnitude of rainfall change, particularly in the northern farming regions. Consequently, the clearest opportunities for ‘in-situ’ genetic gains for abiotic stresses are in developing better adaptation to higher temperatures (e.g. control of phenological stage durations, and tolerance to stress) and, for C3 species, in exploiting the (relatively small) fertilisation effects of elevated CO2. For most cultivated plant species, it remains to be demonstrated how much genetic variation exists for these traits and what value can be delivered via commercial varieties. Biotechnology-based breeding technologies (marker-assisted breeding and genetic modification) will be essential to accelerate genetic gain, but their application requires additional investment in the understanding, genetic characterisation, and phenotyping of complex adaptive traits for climate-change conditions.

scholarly journals EFEKTIVITAS KOMBINASI MIKROORGANISME DAN TUMBUHAN AIR Lemna minor SEBAGAI BIOREMEDIATOR DALAM MEREDUKSI SENYAWA AMONIAK, NITRIT, DAN NITRAT PADA LIMBAH PENCUCIAN IKAN

2016 ◽  
Vol 5 (3) ◽  
pp. 80-90
Author(s):  
Alfian Dony Saputra ◽  
Haeruddin Haeruddin ◽  
Niniek Widyorini
Keyword(s):  
Waste Water ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Outer Part ◽  
Biological Method ◽  
Fish Processing ◽  
Processing Industry ◽  
Effectiveness Analysis ◽  
Main Variable ◽  
Negative Effect

ABSTRAK Limbah pencucian ikan bersumber dari kegiatan pencucian bagian luar dan dalam tubuh ikan. Limbah pencucian ikan memiliki kandungan senyawa amoniak, nitrit, dan nitrat yang tinggi sehingga kemungkinan mempunyai efek negatif bagi lingkungan. Sebagian besar industri pengolahan ikan belum melakukan pengolahan limbah cairnya dengan baik. Bioremediasi merupakan metode biologi dengan memanfaatkan mikroorganisme dan tumbuhan air Lemna minor dalam pengolahan air limbah. Penelitian ini bertujuan untuk mengetahui efektivitas dan pengaruhdari kombinasi mikroorganisme dan Lemna minor dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Metode penelitian yang digunakan adalah eksperimen skala laboratorium dimana wadah percobaan berisi limbah pencucian ikan dengan volume 1 Liter. Desain penelitian yang digunakan yaitu percobaan faktorial 3 x 3 dengan 2 faktor, sehingga terdapat 9 kombinasi perlakuan M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, dan M10L100, dimana “M” faktor konsentrasi mikroorganisme (1 mL/L, 5 mL/L, 10 mL/L), sedangkan “L” faktor bobot biomassaLemna minor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). Variabel utama penelitian adalah amoniak, nitrit, dan nitrat yang didukung oleh temperatur, pH, dan oksigen terlarut. Analisis data dengan menggunakan analisis efektivitas, uji two way Anova, dan uji Beda Nyata Jujur. Hasil penelitian menunjukkan bahwa nilai efektivitas berkisar antara 40,85% - 74,03% (amoniak), 42,21% - 74,10% (nitrit), dan 3,19% - 34,65% (nitrat). Pengaruh interaksi kombinasi mikroorganisme dan Lemna minor yaitu terdapat pengaruh yang nyata dan efektif dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Kata Kunci: Amoniak; Bioremediasi; Lemna minor; Limbah Pencucian Ikan; Mikroorganisme; Nitrat; Nitrit ABSTRACT Fish washery waste derived from washing inner and outer part of fish body.Fish washery waste containshigh ammonia, nitrite, and nitrate which may have negative effect for the environment.Most of the fish processing industry are not doing the processing of waste water properly yet. Bioremediation is a biological method by using microorganisms and aquatic plant Lemna minor in wastewater treatment. The aims of study is to determine the effectiveness anda effect of the use of microorganism and Lemna minor combination in effort to reduce ammonia, nitrite, and nitrate compound in fish washery waste. The method used is laboratory-scale experiments where the experimental containers containing fish washery waste with a volume of 1 Liter. 3 x 3 factorial with 2 factor method design were used, so there are nine treatment combinations of M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, and M10L100, where "M" forconcentrationof microorganisms factor (1 mL/L, 5mL/L, 10 mL/L), while the "L" for biomass weight of Lemna minorfactor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). The main variable of this study are ammonia, nitrite, and nitrate supported by temperature, pH, and Dissolved Oxygen. The data was analyzed using effectiveness analysis, two way Anova, and Least Signifficant Difference methode. The results show that the concentration of ammonia, nitrite, and nitrate decreased after 96 hours for all treatmentscombination. The effectiveness value, ranged between 40.85% - 74.03% (ammonia), 42.21% - 74.10% (nitrite), and 3.19% - 34.65% (nitrate). There is a signifficant influence and effective in combination of microorganisms and Lemna minor to reduce ammonia, nitrite, and nitrate compound in fish washery waste. Keywords: Ammonia; Bioremediation; Lemna minor; Fish Washery Waste; Microorganism; Nitrate;Nitrite

scholarly journals Comparison of Four Production Systems for Dutch Iris in a Tobacco Transplant Greenhouse

2005 ◽  
Vol 15 (1) ◽  
pp. 173-176
Author(s):  
Carl E. Niedziela ◽  
Christopher D. Mullins ◽  
T. David Reed ◽  
William H. Swallow ◽  
Eric Eberly
Keyword(s):  
Nicotiana Tabacum ◽  
Economic Analysis ◽  
Production Systems ◽  
The Other ◽  
Local Market ◽  
Cut Flowers ◽  
Growing Conditions

Pre-cooled bulbs of two dutch iris (Iris ×hollandica) cultivars, Ideal and White Wedgewood, were grown and harvested as cut flowers in four production systems in a tobacco (Nicotiana tabacum) transplant greenhouse from late October until late January in two consecutive production years (2000-01 and 2001-02). All production systems (lily crates, lay-flat bags, pots, and float trays) utilized the same commercial peat-vermiculite, tobacco germination substrate. Stems developed more quickly but were shorter and lighter in 2001-02 than 2000-01 due to warmer growing conditions. Stems grown in float trays were shorter and lighter than other treatments in 2000-01 but similar to the others in 2001-02. Stems grown in lay-flat bags flowered earlier with similar or greater stem lengths and fresh weights as the other systems. Stems of `White Wedgewood' were longer and heavier than `Ideal'. In general, `White Wedgewood' provided more consistent production than `Ideal' in both production seasons. An economic analysis in this study concludes that a grower is unlikely to make money growing dutch iris in a tobacco transplant greenhouse using these production systems unless there is a targeted local market.

scholarly journals Micro-Living: Learning to Live Large in Small Spaces

2021 ◽  
Author(s):  
◽  
Simon Richmond
Keyword(s):  
New Zealand ◽  
Public Perception ◽  
Design Research ◽  
Design Method ◽  
High Density ◽  
Design Strategies ◽  
Spatial Design ◽  
The Future ◽  
Negative Effect ◽  
Living Environments

<p>High-density living has always been proclaimed as a way of the future, but the future is now here and we are plagued by inadequate, uninviting city-living environments. This design research paper aims to produce an alternate design method that can be applied to apartment living in New Zealand to produce positive, affordable apartment designs.  The late 20th and early 21st centuries has seen urban New Zealand become an increasingly popular place to live. Large numbers are drawn to the cities by the convenience of closer proximity to amenities and greater job prospects. This urbanisation overlaps with the constant growth of the country’s overall population which, combined, puts pressure on cities as land becomes an increasingly rare commodity. In response, cities often expand outward. The negative effect of this has been heavily documented.  The introduction of high density living solutions has attempted to combat the ever increasing ‘suburban sprawl.’ Many apartment complexes have risen in response to this demand, especially in the cities of Auckland and Wellington. However, this is where the problem develops. A large proportion of smaller, more affordable apartments have been identifi ed to be poorly designed, producing low quality spaces and unsatisfactory living environments. Moreover, the public perception of these ‘shoebox’ apartments is highly negative.  This research not only investigates the issues associated with the small apartments in New Zealand but seeks to improve upon them by learning from an international precedent. The Japanese architectural movement of Kyosho-Jutaku or Micro-living provides urban accommodation through space effi cient stand-alone dwellings. These dwellings were developed in response to the harsh urban and economic conditions in the early 1990s and continue to be built throughout Japan’s urban prefectures. The architects of Japanese micro-architecture approach small spaces with design strategies resulting in interiors which appear expansive beyond their physical limits and produce quality living environments. Through the analysis and diagrammatic formulation of these Japanese micro-architecture design strategies, this research aims to produce an applicable technique for ‘micro’ design in New Zealand. The contexts are removed allowing the singular strategies to be understood and manipulated, expanding the design possibilities for each technique. Ultimately, this thesis tests the applicability of planning and spatial design strategies, adapted from Japanese micro-architecture, to a New Zealand context in the development of small, high quality urban apartments.</p>

scholarly journals Micro-Living: Learning to Live Large in Small Spaces

2021 ◽  
Author(s):  
◽  
Simon Richmond
Keyword(s):  
New Zealand ◽  
Public Perception ◽  
Design Research ◽  
Design Method ◽  
High Density ◽  
Design Strategies ◽  
Spatial Design ◽  
The Future ◽  
Negative Effect ◽  
Living Environments

<p>High-density living has always been proclaimed as a way of the future, but the future is now here and we are plagued by inadequate, uninviting city-living environments. This design research paper aims to produce an alternate design method that can be applied to apartment living in New Zealand to produce positive, affordable apartment designs.  The late 20th and early 21st centuries has seen urban New Zealand become an increasingly popular place to live. Large numbers are drawn to the cities by the convenience of closer proximity to amenities and greater job prospects. This urbanisation overlaps with the constant growth of the country’s overall population which, combined, puts pressure on cities as land becomes an increasingly rare commodity. In response, cities often expand outward. The negative effect of this has been heavily documented.  The introduction of high density living solutions has attempted to combat the ever increasing ‘suburban sprawl.’ Many apartment complexes have risen in response to this demand, especially in the cities of Auckland and Wellington. However, this is where the problem develops. A large proportion of smaller, more affordable apartments have been identifi ed to be poorly designed, producing low quality spaces and unsatisfactory living environments. Moreover, the public perception of these ‘shoebox’ apartments is highly negative.  This research not only investigates the issues associated with the small apartments in New Zealand but seeks to improve upon them by learning from an international precedent. The Japanese architectural movement of Kyosho-Jutaku or Micro-living provides urban accommodation through space effi cient stand-alone dwellings. These dwellings were developed in response to the harsh urban and economic conditions in the early 1990s and continue to be built throughout Japan’s urban prefectures. The architects of Japanese micro-architecture approach small spaces with design strategies resulting in interiors which appear expansive beyond their physical limits and produce quality living environments. Through the analysis and diagrammatic formulation of these Japanese micro-architecture design strategies, this research aims to produce an applicable technique for ‘micro’ design in New Zealand. The contexts are removed allowing the singular strategies to be understood and manipulated, expanding the design possibilities for each technique. Ultimately, this thesis tests the applicability of planning and spatial design strategies, adapted from Japanese micro-architecture, to a New Zealand context in the development of small, high quality urban apartments.</p>

Diagnostics of Errors at Component Surface by Vision Recognition in Production Systems

2014 ◽  
Vol 616 ◽  
pp. 227-235 ◽  
Author(s):  
Kamil Židek ◽  
Vladislav Maxim ◽  
Radoslav Sadecký
Keyword(s):  
Production Line ◽  
Surface Coverage ◽  
Production Systems ◽  
Conveyor Belt ◽  
Camera System ◽  
C Language ◽  
Edge Detectors ◽  
Part Surface ◽  
Imperfect Coverage ◽  
Scratch Detection

The article deals with the diagnostics of components surface after painting by camera system in real-time. This solution is especially suitable for implementation to automatized production line above the conveyor belt. The faults on the part surface can be detected as scratches, imperfect surface coverage and dirt stuck to the surface. The scratch detection is based on edge detectors, imperfect coverage are checked by histogram comparison and all other errors are detected by counter detectors. The developed software uses open source library OpenCV and is written in C++ language. The software solution is platform independent. Final algorithm is implemented to embedded device based on SoC.

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