scholarly journals Evaluating carbonate dissolution and precipitation in a short time-frame using SEM: techniques and preliminary results from Postojna Cave, Slovenia

2021 ◽  
Vol 50 (2-3) ◽  
Author(s):  
Vanessa Johnston ◽  
Adrijan Košir ◽  
Andrea Martín Pérez
Keyword(s):  
Time Frame ◽  
Carbonate Dissolution ◽  
Physical Weathering ◽  
Preliminary Results ◽  
Geological Processes ◽  
Field Environment ◽  
Before And After ◽  
Cave Environment ◽  
Short Time ◽  
Dissolution And Precipitation

Carbonate dissolution and precipitation are important geological processes whose rates often require quantification. In natural settings, these processes may be taking place at a slow rate, and thus, it may not be easily visible which of these processes is occurring. Alternatively, if the effects of precipitation/dissolution are visible, it may not be clear if they are still underway or an artefact of past conditions. Moreover, these two opposing processes may flip states depending on the environmental conditions, such as, on a seasonal basis. Here, we present the technical details and preliminary results of a method using carbonate tablets and Scanning Electron Microscopy (SEM) to evaluate which process (carbonate dissolution or precipitation) is occurring, using as an example, a cave environment. Our method involves making tablets by encasing blocks of carbonate rock into resin and polishing these to form a completely flat and smooth “zero surface”. These tablets are observed under SEM in exactly the same points both before and after exposure to the field environment, using a system of marking lines at specific locations on the resin. Our results show significant differences in the before and after images of the tablet surface after just six weeks in the cave. Furthermore, the use of the insoluble resin zero surface permits a comparison of the starting height with the new dissolved/precipitated surface that can be used to quantitatively estimate the rate of dissolution/precipitation happening at a field location in a relatively short time-frame (weeks/months). This method could be used in numerous natural and industrial settings to identify these processes that can be caused purely geochemically, but also through microbialmediation and physical weathering.

Evaluation of Metal Contents in Correlation with Phytosanitary Treatments at Vineyard

2017 ◽  
Vol 68 (6) ◽  
pp. 1289-1293
Author(s):  
Oana Mihai ◽  
Octav Pantea ◽  
Daniela Roxana Popovici ◽  
Catalina Gabriela Gheorghe
Keyword(s):  
Soil Samples ◽  
Flame Atomic Absorption ◽  
Mobile Forms ◽  
Before And After ◽  
Phytosanitary Treatment ◽  
Zinc Concentrations ◽  
Zinc Levels ◽  
Ph Range ◽  
In The Beginning ◽  
Short Time

The present work aims with the evaluation of copper, manganese and zinc concentrations (mobile forms) from vineyard soil before and after phytosanitary treatment with Curzate Manox and Dithane M-45 compounds, during and after remanence period. Different vineyard soils types were collected at 0-20 cm and 20-40 cm depths. Flame Atomic Absorption Spectroscopy (FAAS) method was used for measurements of the micronutrients. The soil samples were analyzed after 5 and 21 days after treatment application. Since copper is mainly accumulates in the upper layer following fungicidal sprays application, high levels of copper concentrations are obtained. The soil samples exhibits different behavior in terms of manganese and zinc contents. Manganese and zinc levels are classified as medium in the beginning of the experiment (Mn-M0 and Zn-M0), whereas these levels increased in the soil samples (at moments M1- 5 days and M2- 21 days after treatment). This behavior can be due to the Mancozeb decomposition, knowing that Mancozeb decomposes in the pH range 5-9 and it remains short time into the soil.

scholarly journals Polyethylene Migration from Food Packaging on Cheese Detected by Raman and Infrared (ATR/FT-IR) Spectroscopy

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3872
Author(s):  
Klytaimnistra Katsara ◽  
George Kenanakis ◽  
Zacharias Viskadourakis ◽  
Vassilis M. Papadakis
Keyword(s):  
Vibrational Spectroscopy ◽  
Food Packaging ◽  
Time Frame ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ft Ir ◽  
Comparative Results ◽  
Short Time ◽  
And Storage ◽  
Ft Ir Spectroscopy

For multiple years, food packaging migration has been a major concern in food and health sciences. Plastics, such as polyethylene, are continuously utilized in food packaging for preservation and easy handling purposes during transportation and storage. In this work, three types of cheese, Edam, Kefalotyri and Parmesan, of different hardness were studied under two complementary vibrational spectroscopy methods, ATR-FTIR and Raman spectroscopy, to determine the migration of low-density polyethylene from plastic packaging to the surface of cheese samples. The experimental duration of this study was set to 28 days due to the degradation time of the selected cheese samples, which is clearly visible after 1 month in refrigerated conditions at 4 °C. Raman and ATR-FTIR measurements were performed at a 4–3–4–3 day pattern to obtain comparative results. Initially, consistency/repeatability measurement tests were performed on Day0 for each sample of all cheese specimens to understand if there is any overlap between the characteristic Raman and ATR-FTIR peaks of the cheese with the ones from the low-density polyethylene package. We provide evidence that on Day14, peaks of low-density polyethylene appeared due to polymeric migration in all three cheese types we tested. In all cheese samples, microbial outgrowth started to develop after Day21, as observed visually and under the bright-field microscope, causing peak reverse. Food packaging migration was validated using two different approaches of vibrational spectroscopy (Raman and FT-IR), revealing that cheese needs to be consumed within a short time frame in refrigerated conditions at 4 °C.

Deep fluids and their role in hydrocarbon migration and oil deposit formation exemplified by supercritical СO2

2021 ◽  
pp. 1-11
Author(s):  
Sara LIFSHITS
Keyword(s):  
Supercritical Fluid ◽  
Oil And Gas ◽  
Gas Permeability ◽  
Sedimentary Rocks ◽  
Source Rocks ◽  
Reservoir Properties ◽  
Hydrocarbon Migration ◽  
Geological Processes ◽  
Before And After ◽  
Oil Source

ABSTRACT Hydrocarbon migration mechanism into a reservoir is one of the most controversial in oil and gas geology. The research aimed to study the effect of supercritical carbon dioxide (СО2) on the permeability of sedimentary rocks (carbonates, argillite, oil shale), which was assessed by the yield of chloroform extracts and gas permeability (carbonate, argillite) before and after the treatment of rocks with supercritical СО2. An increase in the permeability of dense potentially oil-source rocks has been noted, which is explained by the dissolution of carbonates to bicarbonates due to the high chemical activity of supercritical СО2 and water dissolved in it. Similarly, in geological processes, the introduction of deep supercritical fluid into sedimentary rocks can increase the permeability and, possibly, the porosity of rocks, which will facilitate the primary migration of hydrocarbons and improve the reservoir properties of the rocks. The considered mechanism of hydrocarbon migration in the flow of deep supercritical fluid makes it possible to revise the time and duration of the formation of gas–oil deposits decreasingly, as well as to explain features in the formation of various sources of hydrocarbons and observed inflow of oil into operating and exhausted wells.

scholarly journals High Oxygen Packaging of Atlantic Cod Fillets Inhibits Known Spoilage Organisms, but Sensory Quality Is Not Improved Due to the Growth of Carnobacterium/Carnobacteriaceae

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1754
Author(s):  
Anlaug Ådland Hansen ◽  
Solveig Langsrud ◽  
Ingunn Berget ◽  
Mari Øvrum Gaarder ◽  
Birgitte Moen
Keyword(s):  
Shelf Life ◽  
Sensory Quality ◽  
Atlantic Cod ◽  
Bacterial Load ◽  
Modified Atmosphere Packaging ◽  
Volatile Components ◽  
Spoilage Bacteria ◽  
Before And After ◽  
Thawing Process ◽  
Short Time

Improved quality control and prolonged shelf life are important actions in preventing food waste. To get an overview of the bacterial diversity of fillets from live stored mature Atlantic cod, bacterial isolates were identified before and after storage (air and vacuum) and freezing/thawing. Based on the load of dominating bacteria, the effect of different packaging methods and a short freezing/thawing process on prolonged shelf-life was evaluated (total viable counts, bacteriota, sensory attributes, and volatile components). Hand filleted (strict hygiene) cod fillets had a low initial bacterial load dominated by the spoilage organism Photobacterium, whereas industrially produced fillets had higher bacterial loads and diversity (Pseudomonas, Arthrobacter, Psychrobacter, Shewanella). The identified bacteria after storage in vacuum or air were similar to the initially identified bacteria. Bacteriota analysis showed that a short time freezing/thawing process reduced Photobacterium while modified atmosphere packaging (MAP; 60%CO2/40%O2 or 60%CO2/40%N2) inhibited the growth of important spoilage bacteria (Photobacterium, Shewanella, Pseudomonas) and allowed the growth of Carnobacterium/Carnobacteriaceae and Acinetobacter. Despite being dominated by Photobacterium, fresh fillets stored in MAP 60%CO2/40%N2 demonstrated better sensory quality after 13 days of storage than fillets stored in MAP 60%CO2/40%O2 (dominated by Carnobacterium/Carnobacteriaceae). Carnobacterium spp. or other members of Carnobacteriaceae may therefore be potential spoilage organisms in cod when other spoilage bacteria are reduced or inhibited.

scholarly journals Breeding Strategies to Improve Miscanthus as a Sustainable Source of Biomass for Bioenergy and Biorenewable Products

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 673 ◽  
Author(s):  
John Clifton-Brown ◽  
Kai-Uwe Schwarz ◽  
Danny Awty-Carroll ◽  
Antonella Iurato ◽  
Heike Meyer ◽  
...  
Keyword(s):  
Significant Contribution ◽  
Perennial Grass ◽  
Time Frame ◽  
Eastern Asia ◽  
Germplasm Collections ◽  
Naturally Occurring ◽  
Wide Range ◽  
Yield Quality ◽  
Short Time ◽  
Commercial Expansion

Miscanthus, a C4 perennial grass native to Eastern Asia, is being bred to provide biomass for bioenergy and biorenewable products. Commercial expansion with the clonal hybrid M. × giganteus is limited by low multiplication rates, high establishment costs and drought sensitivity. These limitations can be overcome by breeding more resilient Miscanthus hybrids propagated by seed. Naturally occurring fast growing indigenous Miscanthus species are found in diverse environments across Eastern Asia. The natural diversity provides for plant breeders, the genetic resources to improve yield, quality, and resilience for a wide range of climates and adverse abiotic stresses. The challenge for Miscanthus breeding is to harness the diversity through selections of outstanding wild types, parents, and progenies over a short time frame to deploy hybrids that make a significant contribution to a world less dependent on fossil resources. Here are described the strategies taken by the Miscanthus breeding programme at Aberystwyth, UK and its partners. The programme built up one of the largest Miscanthus germplasm collections outside Asia. We describe the initial strategies to exploit the available genetic diversity to develop varieties. We illustrate the success of combining diverse Miscanthus germplasm and the selection criteria applied across different environments to identify promising hybrids and to develop these into commercial varieties. We discuss the potential for molecular selections to streamline the breeding process.

Hydrothermal Sintering under Mild Temperature Conditions: Preparation of Calcium-deficient Hydroxyapatite Compacts

2010 ◽  
Vol 65 (8) ◽  
pp. 1038-1044 ◽  
Author(s):  
Kazumichi Yanagisawa ◽  
Jae-Hyen Kim ◽  
Chisato Sakata ◽  
Ayumu Onda ◽  
Eri Sasabe ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Hot Pressing ◽  
Reaction Parameter ◽  
High Bulk Density ◽  
Temperature And Pressure ◽  
Mild Temperature ◽  
Short Time ◽  
High Bulk ◽  
Dissolution And Precipitation

Calcium-deficient hydroxyapatite (CDHA) prepared by the coprecipitation method was solidified by the hydrothermal hot-pressing technique, and compacts of CDHA with high bulk density beyond 80% were obtained at 200 ℃. Each reaction parameter, viz. reaction temperature, pressure, and time, was systematically changed from the standard conditions to investigate its effects on density, Vickers hardness, and Ca/P ratio of the compacts obtained. The reaction temperature and pressure had a large effect on densification, but not the reaction time because the densification proceeds in a short time. The densification by hydrothermal hot-pressing involved dissolution and precipitation of the starting CDHA powder, so that the Ca/P ratio changed from 1.52 of the starting powders to 1.61 of the compact obtained by hydrothermal hot-pressing at 200 ℃ and 35 MPa for 24 h with the addition of 10 wt.-% water

Ranking the explanatory power of factors associated with worldwide new Covid-19 cases

2021 ◽  
Author(s):  
Aristides Moustakas
Keyword(s):  
Explanatory Power ◽  
Interdisciplinary Approach ◽  
Time Frame ◽  
Variance Partitioning ◽  
Total Variance ◽  
Disease Spread ◽  
Spatial Spread ◽  
Global Pandemic ◽  
Governmental Intervention ◽  
Short Time

Abstract Disease spread is a complex phenomenon requiring an interdisciplinary approach. Covid-19 exhibited a global spatial spread in a very short time frame resulting in a global pandemic. Data of new Covid-19 cases per million were analysed worldwide at the spatial scale of a country and time replicated from the end of December 2019 to late May 2020. Data driven analysis of epidemiological, economic, public health, and governmental intervention variables was performed in order to select the optimal variables in explaining new Covid-19 cases across all countries in time. Sequentially, hierarchical variance partitioning of the optimal variables was performed in order to quantify the independent contribution of each variable in the total variance of new Covid-19 cases per million. Results indicated that from the variables available new tests per thousand explained the vast majority of the total variance in new cases (51.6%) followed by the governmental stringency index (15.2%). Availability of hospital beds per 100k inhabitants explained 9% extreme poverty explained 8.8%, hand washing facilities 5.3%, the fraction of the population aged 65 or older explained 3.9%, and other disease prevalence (cardiovascular diseases plus diabetes) explained 2.9%. The percentage of smokers within the population explained 2.6% of the total variance, while population density explained 0.6%.

Crossword Puzzles: Active Learning in Undergraduate Pathology and Medical Education

2009 ◽  
Vol 133 (9) ◽  
pp. 1457-1462
Author(s):  
Anurag Saxena ◽  
Raenelle Nesbitt ◽  
Punam Pahwa ◽  
Sheryl Mills
Keyword(s):  
Student Perceptions ◽  
Small Groups ◽  
Time Frame ◽  
Teaching Tool ◽  
Internet Resource ◽  
Cooperative Groups ◽  
Key Concepts ◽  
Second Year ◽  
Peer Teachers ◽  
Short Time

Abstract Context.—Second-year medical students are introduced to many new terms and concepts in a short time frame in the hematology system and the neoplasia section of the undergraduate pathology course. It is a challenge to provide adequate practice and necessary repetition to reinforce key concepts. Objective.—To determine student perceptions of the usefulness of crosswords as a quick and effective way to reinforce essential concepts and vocabulary. Design.—Crosswords with ensured content validity built on a free Internet resource were completed by the students in collaborative and cooperative groups of 6 to 7 with a reward for the first group to successfully complete the puzzle. Student perceptions of the value of crosswords for their learning were examined in 2003 (39 students) with a survey of yes or no responses and in 2004 (41 students) with a survey using questions with a 5-point Likert scale. Results.—Many students (37 of 39 in 2003 and 24 of 41 in 2004) indicated that crosswords were useful and contributed to their learning. Specifically, crosswords were found to be useful for identifying key concepts and vocabulary and for their collaborative and competitive aspects. Written and informal comments indicated student enthusiasm for and a desire to participate in more of these exercises. Students have transferred this review strategy to other classes and the peer teachers have expressed an interest in it as an adjunct teaching tool. Conclusions.—The judicious use of crosswords was useful for near transfer content and provided an opportunity to discuss and recall essential concepts, think critically, and collaborate in small groups.

scholarly journals Cognitive Vocal Program applied to individuals with signals presbylarynx: preliminary results

CoDAS ◽  
2014 ◽  
Vol 26 (6) ◽  
pp. 503-508 ◽  
Author(s):  
Katia Nemr ◽  
Glaucia Verena Sampaio de Souza ◽  
Marcia Simões-Zenari ◽  
Domingos Hiroshi Tsuji ◽  
Adriana Hachiya ◽  
...  
Keyword(s):  
High Speed ◽  
Vocal Production ◽  
Maximum Phonation Time ◽  
Preliminary Results ◽  
Perceptual Evaluation ◽  
Articulatory Movements ◽  
Before And After ◽  
Screening Protocol ◽  
Program Intervention ◽  
Vocal Quality

PURPOSE: To propose and verify the feasibility of a vocal program intervention in patients with presbylarynx signs with or without vocal complaints. METHOD: Among 20 elder participants of the current research, 3 female patients with median age of 67 years were chosen for the pilot study. Laryngological examination, vocal recording with CAPE-V (Consensus Auditory-Perceptual Evaluation of Voice) protocol, and Screening Protocol of Risk of Dysphonia (SPRD) were conducted before and after the program intervention. They joined the Cognitive Vocal Program for presbyphonia based on the genetic epistemology by Jean Piaget associated with vocal techniques based on scientific literature. This program is structured with six sessions and each one of them is focused in different aspects of vocal production. RESULTS: After the program intervention, some aspects such as loudness, coordination between breathing and speaking, accuracy in articulatory movements, jitter, and harmonics-to-noise ratio improved with parameters within the expected range for the age group. Three female participants were observed for better vocal quality, higher fundamental frequency, and better maximum phonation time. In two cases, tension related to loudness elevation and better scores on SPRD was observed. Using by high-speed laryngeal image, we also observed reduction of presbylarynx signs, and remarkable improvement in glottis closure competence and mucosal wave movement of the patients with and without vocal complaints. CONCLUSION: The preliminary results suggest encouraging prospects for the proposal with improvement in the aspects analyzed. This program was well designed and did not require any further adjustments.

scholarly journals Effects of bamboo dominance and palm-heart harvesting on the phylogenetic structure of the seed and seedling communities in an old-growth Atlantic Forest

2017 ◽  
Vol 33 (5) ◽  
pp. 309-316
Author(s):  
Daniella Schweizer ◽  
Débora Cristina Rother ◽  
Ana Elena Muler ◽  
Ricardo Ribeiro Rodrigues ◽  
Marco Aurélio Pizo ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Atlantic Forest ◽  
Time Frame ◽  
Seed Rain ◽  
Old Growth ◽  
Phylogenetic Structure ◽  
Palm Heart ◽  
Forest Remnant ◽  
Before And After ◽  
Seedling Community

Abstract:A comprehensive assessment of the effect of disturbances on tropical and subtropical forests is needed to better understand their impacts on forest structure and diversity. Although taxonomic and functional diversity measures have been successfully adopted in this context, phylogenetic diversity metrics are still poorly explored. We compared the phylogenetic structure of the seed rain and regenerating seedling community in patches of an old-growth Atlantic Forest remnant dominated or not by a ruderal bamboo species, Guadua tagoara. We sampled those patches before and after illegal harvesting of the palm Euterpe edulis thus assessing if the harvesting led to changes in the phylogenetic structure of the seed rain and the regenerating community in both patches. Bamboo-dominated patches showed a significantly higher presence of species in the seed rain that were more distantly related to each other in the phylogeny than expected by chance compared with patches without bamboos, but this difference disappeared after palm-heart harvesting. Contrary to what we expected, we did not find significant changes in the phylogenetic structure of seedlings before or after palm-heart harvesting. The phylogenetic structure at the tips of the phylogeny was random overall. The maintenance of a higher presence of far relatives in the phylogeny of the seedling community suggests, assuming trait conservatism, that despite bamboo dominance and palm-heart harvesting, functional diversity is being preserved at least in the early regenerating stages and in the time frame of the study. However, higher presence of pioneer taxa after palm-heart harvest indicates that this disturbance may lead old-growth areas to earlier successional stages.

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