A comparison of strawberry (Fragaria x ananassa) cultivars affected by different cultural practices in two production systems

Strawberry cultivar performance affected by various cultural practices was investigated in two production systems. The first study investigated strawberry yield, fruit quality, and production timing of eight cultivars when using black and red plastic mulches in a high tunnel production system. The high tunnel increased air temperatures and advanced strawberry fruiting by four to six weeks compared to local openield production. The second study investigated plant growth, yield, and fruit quality of 10 cultivars fertilized with organic or conventional fertilizer and irrigated once or twice daily with the same total irrigation volume in a container system. Strawberry cultivars varied in their yield and quality variables including soluble solids contents, firmness, and titratible acidity in the two production systems. Mulch color, fertilizer type, and irrigation frequency had varying effects on the growth microenvironment, fruit yield, and certain quality variables

Utilization of Outdoor Resources to Enhance Understanding of Geosciences

Societal awareness and general understanding of the diversity of geosciences environments and phenomena across regions is vital. The primary method to obtain information about geosciences is through mass media. However, there is little coverage of geosciences information and the public may not trust it because of low geosciences awareness. Geosciences are rarely included as part of K-12 curricula and are optional at the collegiate level, contributing to the public deficiency regarding awareness and understanding of the geosciences. This research study investigated methods utilizing outdoor resources in an effort to increase region-specific understanding and awareness of geosciences among diverse groups. A Mississippi K-12 educator professional development session and two middle-high schools were assessed for impact on understanding and interest related to geosciences. All participants utilized outdoor resources to model erosional processes and potential natural hazard events. Both participating schools have high underrepresented minority populations. Pre assessment evaluated participant awareness of Mississippi natural hazards. Teachers and student participants all demonstrated a low awareness of erosion processes specific to the region. Teachers completed erosion models indoors or outdoors, with indoor participants having a significant increase in earth science interest. All student participants completed the erosion model outside, with pre-post erosion comprehension resulting in significant increases for both the middle and high schools. The middle school had significant gains in earth science interest while the high school had a significant decrease regarding careers in geosciences. Virtual field guides developed by online graduate students demonstrating personal understanding of broad geosciences concepts in their local region were evaluated pre-post for impact on geosciences awareness, understanding, and confidence. Awareness factors included geographical community size and locations included in the field guide to demonstrate participant understanding. Significant increases in awareness regarding geoscience resources, including those outdoors, occurred. Significant increases also occurred in confidence utilizing geosciences resources and communicating about geosciences. The majority agreed that the experience of creating the field guide enhanced understanding of geosciences and interest in outdoor activities. Geographical size of participants’ residential communities was significantly related to awareness of regional locations, with urban residents including fewer outdoor locations in the field guide

Evaluation of dissociated and steam-reformed methanol as automotive engine fuels

Dissociated and steam reformed methanol were evaluated as automotive engine fuels. Advantages and disadvantages in using methanol in the reformed rather than liquid state were discussed. Engine dynamometer tests were conducted with a four cylinder, 2.3 liter, spark ignition automotive engine to determine performance and emission characteristics operating on simulated dissociated and steam reformed methanol (2H2 + CO and 3H2 + CO2 respectively), and liquid methanol. Results are presented for engine performance and emissions as functions of equivalence ratio, at various throttle settings and engine speeds. Operation on dissociated and steam reformed methanol was characterized by flashback (violent propagation of a flame into the intake manifold) which limited operation to lower power output than was obtainable using liquid methanol. It was concluded that: an automobile could not be operated solely on dissociated or steam reformed methanol over the entire required power range - a supplementary fuel system or power source would be necessary to attain higher powers; the use of reformed mechanol, compared to liquid methanol, may result in a small improvement in thermal efficiency in the low power range; dissociated methanol is a better fuel than steam reformed methanol for use in a spark ignition engine; and use of dissociated or steam reformed methanol may result in lower exhaust emissions compared to liquid methanol

Comparison of Advanced Battery Technologies for Electric Vehicles

Battery technologies of different chemistries, manufacture and geometry were evaluated as candidates for use in Electric Vehicles (EV). The candidate batteries that were evaluated include four single cell and seven multi-cell modules representing four technologies: Lead-Acid, Nickel-Cadmium, Nickel-Metal Hydride and Zinc-Bromide. A standard set of testing procedures for electric vehicle batteries, based on industry accepted testing procedures, and any tests which were specific to individual battery types were used in the evaluations. The batteries were evaluated by conducting performance tests, and by subjecting them to cyclical loading, using a computer controlled charge--discharge cycler, to simulate typical EV driving cycles. Criteria for comparison of batteries were: performance, projected vehicle range, cost, and applicability to various types of EVs. The four battery technologies have individual strengths and weaknesses and each is suited to fill a particular application. None of the batteries tested can fill every EV application

The Absence of Pyruvate Kinase Affects Glucose-Dependent Carbon Catabolite Repression in Bacillus subtilis

Pyruvate is a key intermediate of diverse metabolic pathways of central carbon metabolism. In addition to being the end product of glycolysis, pyruvate is an essential carbon distribution point to oxidative metabolism, amino acid and fatty acid syntheses, and overflow metabolite production. Hence, a tight regulation of pyruvate kinase (Pyk) activity is of great importance. This study aimed to analyze targeted metabolites from several pathways and possible changes in Bacillus subtilis lacking Pyk. Wild type and Δpyk cells were cultivated in chemically defined medium with glucose and pyruvate as carbon sources, and the extracted metabolites were analyzed by 1H-NMR, GC-MS, HPLC-MS, and LC-MS/MS. The results showed that the perturbation created in the pyruvate node drove an adaptation to new conditions by altering the nutritional compounds’ consumption. In Δpyk, pyruvate, which is subject to glucose-dependent carbon catabolite repression, did not comply with the hierarchy in carbon source utilization. Other metabolic alterations were observed such as the higher secretion of the overflow metabolites acetoin and 2,3-butanediol by Δpyk. Our results help to elucidate the regulatory transport of glucose and pyruvate in B. subtilis and possible metabolic reroute to alternative pathways in the absence of Pyk

Self-assembled mono- and bilayers on gold electrodes to assess antioxidants—a comparative study

Oxidative stress is considered as an imbalance of reactive species over antioxidants, leading to diseases and cell death. Various methods have been developed to determine the antioxidant potential of natural or synthetic compounds based on the ability to scavenge free radicals. However, most of them lack biological relevance. Here, a gold-based self-assembled monolayer (SAM) was compared with a gold-supported lipid bilayer as models for the mammalian cell membrane to evaluate the free radical scavenging activity of different antioxidants. The oxidative damage induced by reactive species was verified by cyclic and differential pulse voltammetry and measured by the increase of electrochemical peak current of a redox probe. Trolox, caffeic acid (CA), epigallocatechin gallate (EGCG), ascorbic acid (AA), and ferulic acid (FA) were used as model antioxidants. The change in the decrease of the electrochemical signal reflecting oxidative membrane damage confirms the expected protective role. Both model systems showed similar efficacies of each antioxidant, the achieved order of radical scavenging potential is as follows: Trolox > CA > EGCG > AA > FA. The results showed that the electrochemical assay with SAM-modified electrodes is a stable and powerful tool to estimate qualitatively the antioxidative activity of a compound with respect to cell membrane protection against biologically relevant reactive species. © 2020, The Author(s)

Fed-batch process for the psychrotolerant marine bacterium Pseudoalteromonas haloplanktis

<p>Abstract</p> <p>Background</p> <p><it>Pseudoalteromonas haloplanktis </it>is a cold-adapted γ-proteobacterium isolated from Antarctic sea ice. It is characterized by remarkably high growth rates at low temperatures. <it>P. haloplanktis </it>is one of the model organisms of cold-adapted bacteria and has been suggested as an alternative host for the soluble overproduction of heterologous proteins which tend to form inclusion bodies in established expression hosts. Despite the progress in establishing <it>P. haloplanktis </it>as an alternative expression host the cell densities obtained with this organism, which is unable to use glucose as a carbon source, are still low. Here we present the first fed-batch cultivation strategy for this auspicious alternative expression host.</p> <p>Results</p> <p>The key for the fed-batch cultivation of <it>P. haloplanktis </it>was the replacement of peptone by casamino acids, which have a much higher solubility and allow a better growth control. In contrast to the peptone medium, on which <it>P. haloplanktis </it>showed different growth phases, on a casamino acids-containing, phosphate-buffered medium <it>P. haloplanktis </it>grew exponentially with a constant growth rate until the stationary phase. A fed-batch process was established by feeding of casamino acids with a constant rate resulting in a cell dry weight of about 11 g l^-1(OD₅₄₀= 28) which is a twofold increase of the highest densities which have been obtained with <it>P. haloplanktis </it>so far and an eightfold increase of the density obtained in standard shake flask cultures.</p> <p>The cell density was limited in the fed-batch cultivation by the relatively low solubility of casamino acids (about 100 g l^-1), which was proven by pulse addition of casamino acid powder which increased the cell density to about 20 g l^-1(OD₅₄₀= 55).</p> <p>Conclusion</p> <p>The growth of <it>P. haloplanktis </it>to higher cell densities on complex medium is possible. A first fed-batch fermentation strategy could be established which is feasible to be used in lab-scale or for industrial purposes. The substrate concentration of the feeding solution was found to influence the maximal biomass yield considerably. The bottleneck for growing <it>P. haloplanktis </it>to high cell densities still remains the availability of a highly concentrated substrate and the reduction of the substrate complexity. However, our results indicate glutamic acid as a major carbon source, which provides a good basis for further improvement of the fed-batch process.</p

Innovative Schematic Concept Analysis for a Space Suit Portable Life Support Subsystem

Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power. The PLSS concepts were evaluated using the ExtraVehicular Activity System Sizing Analysis Tool, software created by NASA to analyze integrated system mass, volume, power and thermal loads. The assessment resulted in the Texas Engineering Experiment Station recommending to NASA an evolution path from the existing PLSS to a long duration, low mass PLSS suitable for Martian missions

A case study of climate variability effects on wind resources in South Africa

The wind energy sector is one of the most prominent sectors of the renewable energy industry. However, its dependence on meteorological factors subjects it to climate change. Studies analysing the impact of climate change on wind resources usually only model changes in wind speed. Two elements that have to be calculated in addition to wind speed changes are Annual Energy Production (AEP) and Power Density (PD). This is not only because of the inherent variability between wind speed and wind power generated, but also because of the relative magnitudes of change in energy potentially generated at different areas under varied wind climates. In this study, it was assumed that two separate locations would experience a 10% wind speed increase after McInnes et al. (2010). Given the two locations’ different wind speed distributions, a wind speed increase equal in magnitude is not equivalent to similar magnitudes of change in potential energy production in these areas. This paper demonstrates this fact for each of the case studies. It is of general interest to the energy field and is of value since very little literature exists in the Southern African context on climate change- or variability-effects on the (wind) energy sector. Energy output is therefore dependent not only on wind speed, but also wind turbine characteristics. The importance of including wind power curves and wind turbine generator capacity in wind resource analysis is emphasised

A case study of climate variability effects on wind resources in South Africa

The wind energy sector is one of the most prominent sectors of the renewable energy industry. However, its dependence on meteorological factors subjects it to climate change. Studies analysing the impact of climate change on wind resources usually only model changes in wind speed. Two elements that have to be calculated in addition to wind speed changes are Annual Energy Production (AEP) and Power Density (PD). This is not only because of the inherent variability between wind speed and wind power generated, but also because of the relative magnitudes of change in energy potentially generated at different areas under varied wind climates. In this study, it was assumed that two separate locations would experience a 10% wind speed increase after McInnes et al. (2010). Given the two locations’ different wind speed distributions, a wind speed increase equal in magnitude is not equivalent to similar magnitudes of change in potential energy production in these areas. This paper demonstrates this fact for each of the case studies. It is of general interest to the energy field and is of value since very little literature exists in the Southern African context on climate change- or variability-effects on the (wind) energy sector. Energy output is therefore dependent not only on wind speed, but also wind turbine characteristics. The importance of including wind power curves and wind turbine generator capacity in wind resource analysis is emphasised.http://www.erc.uct.ac.za/jesa/jesa-contents.htm2015-08-30am201