scholarly journals Evaluation of the mulch films biodegradation in soil: a methodological review

2021 ◽  
Author(s):  
Matteo Francioni ◽  
Ayaka Wenhong Kishimoto-Mo ◽  
Shun Tsuboi ◽  
Yuko Takada Hoshino
Keyword(s):  
Mass Loss ◽  
Open Field ◽  
Visual Analysis ◽  
Soil Environment ◽  
Plastic Mulch ◽  
Degradation Rates ◽  
Wide Range ◽  
Polybutylene Succinate ◽  
Mulch Films ◽  
Biodegradation In Soil

Plastic mulch films are widely used in agriculture, but most are not biodegradable in soil. Biodegradable mulch films are blends of different polymers whose composition-ratios vary notably from one product to another. Their degradation rates vary greatly according to the physio-chemical characteristics of the product and according to the properties of the soil and its microbial activity. The objective of this review is to provide an overview of the methods used to estimate the biodegradation performances of biodegradable plastics in the soil. In line with this objective, 80 papers were selected and systematically analyzed to extract information on the characteristics of the soil used in the experiments, the type of polymer analyzed, and the methods used to estimate biodegradation in soil environment. Our systematic analysis showed that studies were carried out under both laboratory-controlled and open-field conditions, with different approaches involving visual analysis, mass loss measurements, spectroscopy, and CO2 measurements. A linear estimation of biodegradation performance for four of the most common biodegradable polymers (i.e., polybutylene succinate, polybutylene succinate-co-adipate, polylactic acid, and polybutylene adipate-co-terephthalate), either pure or blended, showed a very wide range of results that appear only partially comparable. Many of the analyzed papers did not report soil characteristics at all, despite soil being one of the most important factors in the biodegradation process. Although methodologies for estimating biodegradation are well developed, at least under laboratory-controlled conditions, there is a need for a shared methodology to make results comparable among different experiments. Within such a shared methodology, visual analysis or mass loss measurements, despite not being able to scientifically prove the biodegradation of polymers, should not be discarded a priori as they might be useful indicators especially for open field experiments. When using indirect biodegradation indicators such as visual analysis or mass loss, it is necessary to couple them with CO2 measurements or to use materials whose biodegradability in the soil environment has already been tested.

scholarly journals Degradation of biodegradable plastic mulch films in soil environment by phylloplane fungi isolated from gramineous plants

AMB Express ◽  
2012 ◽  
Vol 2 (1) ◽  
pp. 40 ◽  
Author(s):  
Motoo Koitabashi ◽  
Masako T Noguchi ◽  
Yuka Sameshima-Yamashita ◽  
Syuntaro Hiradate ◽  
Ken Suzuki ◽  
...  
Keyword(s):  
Biodegradable Plastic ◽  
Soil Environment ◽  
Plastic Mulch ◽  
Phylloplane Fungi ◽  
Mulch Films

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

scholarly journals Insulative effect of plastic mulch systems and comparison between the effects of different plant types

2020 ◽  
Vol 5 (1) ◽  
pp. 317-324
Author(s):  
Kayla Snyder ◽  
Christopher Murray ◽  
Bryon Wolff
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Plastic Mulch ◽  
Root Zone Temperature ◽  
Tomato Plants ◽  
Black Film ◽  
Black And White ◽  
Mulch Film ◽  
Mulch Films ◽  
Zone Temperature

AbstractTo address agricultural needs of the future, a better understanding of plastic mulch film effects on soil temperature and moisture is required. The effects of different plant type and mulch combinations were studied over a 3.5-month period to better grasp the consequence of mulch on root zone temperature (RZT) and moisture. Measurements of (RZT) and soil moisture for tomato (Solanum lycopersicum), pepper (Capsicum annuum) and carrot (Daucus carota) grown using polyolefin mulch films (black and white-on-black) were conducted in Ontario using a plot without mulch as a control. Black mulch films used in combination with pepper and carrot plants caused similar RZTs relative to uncovered soil, but black mulch film in combination with tomato plants caused a reduction in RZT relative to soil without mulch that increased as plants grew and provided more shade. White-on-black mulch film used in combination with tomatoes, peppers or carrots led to a reduction in RZT relative to soil without mulch that became greater than the temperature of soil without mulch. This insulative capability was similarly observed for black mulch films used with tomato plants. Apart from white-on-black film used in combination with tomatoes, all mulch film and plant combinations demonstrated an ability to stabilize soil moisture relative to soil without mulch. RZT and soil moisture were generally stabilized with mulch film, but some differences were seen among different plant types.

The Sexual and Reproductive Functions, Normal and Perverted, in Relation to Insanity. I. Menstruation: its Commencement, Irregularities, and Cessation. II. the Sexual Instinct and its Abuse. III. Pregnancy, Parturition, etc

1888 ◽  
Vol 34 (147) ◽  
pp. 383-393
Author(s):  
Campbell Clark
Keyword(s):  
Open Field ◽  
Mental Disease ◽  
General Medicine ◽  
Wide Range ◽  
Psychological Medicine ◽  
Collective Experience ◽  
The Subject ◽  
Present Opportunity

In undertaking to introduce a discussion on this very large and important question, I am conscious of my inability to do it justice. No one can possibly cover the wide range of subjects comprised in it; and I am anxious rather to elicit the convictions of more experienced men than to obtrude my own crude and imperfect ideas. My purpose is, therefore, to state the case as briefly as possible, and to introduce questions for discussion in preference to merely ventilating my own ideas. In this way we may arrive at some common points of agreement and materially advance our knowledge of the subject. There can be no two opinions as to the advantage of bringing to a focus the collective experience and conclusions of the various sections of our profession interested in this field of research, and the present opportunity is a particularly good one. The title of the discussion embraces a great deal, and yet does not strictly include topics which might be considered relevant, particularly therapeutics. My aim at the outset will be to invite your special attention to a few questions only, and in order to make the most of our time and concentrate the discussion as much as possible I propose to take each division separately. The subject, viewed as a whole, is so far-reaching and practical as to possess uncommon interest, for it links together medicine and psychological medicine, it gives an open field of discussion to general medicine, obstetrics, and psychology, and it views insanity on its less speculative side, because the more materialistic functions are brought out in strong relief, and sometimes even overshadow the characters of mental disease.

scholarly journals Conservation of Sweet Grape tomatoes using albumin coatings containing phenolic compounds of Spirulina sp. LEB-18.

2017 ◽  
Vol 8 (4) ◽  
pp. 128
Author(s):  
Anelise Christ Ribeiro ◽  
Rui Carlos Zambiazi ◽  
Leonor Almeida de Souza Soares
Keyword(s):  
Phenolic Compounds ◽  
Mass Loss ◽  
Shelf Life ◽  
Visual Analysis ◽  
Water Immersion ◽  
Control Sample ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Edible Coatings ◽  
Phenolic Extracts

The objective of this study was to evaluate the influence of protein globulin-based films and with addition of phenolic compounds extracted from Spirulina sp. LEB-18 in the conservation of tomatoes "Sweet Grape". For this, the tomatoes were immersed for one min in edible coatings, the first based on phenolic extracts derived from Spirulina sp. LEB-18 and ovalbumin (extracted from eggwhite), and the second based just on ovalbumin, beyond the control sample with only water immersion. Tests of pH, of titratable acidity, of color, of soluble solids, of mass loss and visual analysis were taken every 96 h during the 20 day period. The results show that the coating made with phenolic compounds increased the shelf life of tomatoes type "sweet grape".

scholarly journals The nature of the radius valley

2020 ◽  
Vol 643 ◽  
pp. L1 ◽  
Author(s):  
Julia Venturini ◽  
Octavio M. Guilera ◽  
Jonas Haldemann ◽  
María P. Ronco ◽  
Christoph Mordasini
Keyword(s):  
Mass Loss ◽  
Size Distribution ◽  
Point Of View ◽  
Parameter Study ◽  
Type I ◽  
Water Ice ◽  
Wide Range ◽  
Orbital Periods ◽  
Gas Accretion ◽  
Second Peak

The existence of a radius valley in the Kepler size distribution stands as one of the most important observational constraints to understand the origin and composition of exoplanets with radii between those of Earth and Neptune. In this work we provide insights into the existence of the radius valley, first from a pure formation point of view and then from a combined formation-evolution model. We run global planet formation simulations including the evolution of dust by coagulation, drift, and fragmentation, and the evolution of the gaseous disc by viscous accretion and photoevaporation. A planet grows from a moon-mass embryo by either silicate or icy pebble accretion, depending on its position with respect to the water ice line. We include gas accretion, type I–II migration, and photoevaporation driven mass-loss after formation. We perform an extensive parameter study evaluating a wide range of disc properties and initial locations of the embryo. We find that due to the change in dust properties at the water ice line, rocky cores form typically with ∼3 M⊕ and have a maximum mass of ∼5 M⊕, while icy cores peak at ∼10 M⊕, with masses lower than 5 M⊕ being scarce. When neglecting the gaseous envelope, the formed rocky and icy cores account naturally for the two peaks of the Kepler size distribution. The presence of massive envelopes yields planets more massive than ∼10 M⊕ with radii above 4 R⊕. While the first peak of the Kepler size distribution is undoubtedly populated by bare rocky cores, as shown extensively in the past, the second peak can host half-rock–half-water planets with thin or non-existent H-He atmospheres, as suggested by a few previous studies. Some additional mechanisms inhibiting gas accretion or promoting envelope mass-loss should operate at short orbital periods to explain the presence of ∼10–40 M⊕ planets falling in the second peak of the size distribution.

Abstract 17361: How Leptin Harms the Heart in High Fat Diet-Induced Obesity

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Maria Pini
Keyword(s):  
Body Weight ◽  
Mass Loss ◽  
Fat Mass ◽  
High Fat Diet ◽  
Cardiac Fibroblasts ◽  
High Fat ◽  
Wide Range ◽  
Plasma Leptin ◽  
Fat Mass Loss

Introduction: Sedentary lifestyle and excessive calorie intake are risk factors for CVD. We have demonstrated the cardioprotective effect of exercise in aged mice and the critical role of visceral adiposity and its profibrotic secretome in increasing cardiovascular risks in obesity and aging. The association between exercise, lowered plasma leptin and reduced inflammatory leukocytes has been recently shown in patients with atherosclerosis. It remains unclear whether elevated plasma leptin can preserve or alter cardiovascular function in obesity. Methods: We analyzed the effect of high fat diet (HFD) in C57BL/6J male mice on the heart in terms of function, structure, histology and key molecular markers. Two interventions were used: 1) active fat mass loss via exercise (daily swimming) during HFD; 2) passive fat mass loss via surgical removal of the visceral adipose tissue (VAT lipectomy) followed by HFD. Results: HFD increased body weight and adiposity, leading to higher plasma leptin, glucose and insulin levels, compared to control diet (CD) mice. HFD impaired left ventricle (LV) structure (hypertrophy, interstitial fibrosis) and cardiac function (echocardiography, in vivo hemodynamics). Atria of HFD mice had enhanced pro-inflammatory protein production. Exercise reduced circulating leptin levels in HFD mice by 50%, in line with fat mass loss. In contrast, lipectomy reduced visceral fat mass, but body weight, adiposity and plasma leptin did not change. Both exercise and VAT lipectomy improved cardiac contractility, reversed collagen deposition and oxidative stress in HFD mice. Both interventions downregulated LV pro-inflammatory markers. We proved the role of leptin in cardiac remodeling in vitro by incubating primary cardiac fibroblasts with hyperleptinemic plasma from HFD mice. Remarkably, plasma from HFD-EX (exercise) suppressed the fibro-proliferative and pro-inflammatory responses of cardiac fibroblasts. Conclusions: Leptin directly contribute to cardiac fibrosis in obesity via activation and proliferation of cardiac fibroblasts. Understanding how leptin signals to the heart might have implications in a wide range of CVD, potentially helping early stratification and personalized care.

scholarly journals Kinetic and Mechanistic Study of Rhodamine B Degradation by H2O2 and Cu/Al2O3/g-C3N4 Composite

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 317 ◽  
Author(s):  
Chunsun Zhou ◽  
Zhongda Liu ◽  
Lijuan Fang ◽  
Yulian Guo ◽  
Yanpeng Feng ◽  
...  
Keyword(s):  
Rate Constant ◽  
Rhodamine B ◽  
Active Sites ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Mechanistic Study ◽  
Al2o3 Composite ◽  
Degradation Rates ◽  
Wide Range ◽  
Alkaline Conditions

The classic Fenton reaction, which is driven by iron species, has been widely explored for pollutant degradation, but is strictly limited to acidic conditions. In this work, a copper-based Fenton-like catalyst Cu/Al2O3/g-C3N4 was proposed that achieves high degradation efficiencies for Rhodamine B (Rh B) in a wide range of pH 4.9–11.0. The Cu/Al2O3 composite was first prepared via a hydrothermal method followed by a calcination process. The obtained Cu/Al2O3 composite was subsequently stabilized on graphitic carbon nitride (g-C3N4) by the formation of C−O−Cu bonds. The obtained composites were characterized through FT-IR, XRD, TEM, XPS, and N2 adsorption/desorption isotherms, and the immobilized Cu+ was proven to be active sites. The effects of Cu content, g-C3N4 content, H2O2 concentration, and pH on Rh B degradation were systematically investigated. The effect of the catalyst dose was confirmed with a specific reaction rate constant of (5.9 ± 0.07) × 10−9 m·s−1 and the activation energy was calculated to be 71.0 kJ/mol. In 100 min 96.4% of Rh B (initial concentration 20 mg/L, unadjusted pH (4.9)) was removed in the presence of 1 g/L of catalyst and 10 mM of H2O2 at 25 °C, with an observed reaction rate constant of 6.47 × 10−4 s−1. High degradation rates are achieved at neutral and alkaline conditions and a low copper leaching (0.55 mg/L) was observed even after four reaction cycles. Hydroxyl radical (HO·) was identified as the reactive oxygen species by using isopropanol as a radical scavenger and by ESR analysis. HPLC-MS revealed that the degradation of Rh B on Cu/Al2O3/CN composite involves N-de-ethylation, hydroxylation, de-carboxylation, chromophore cleavage, ring opening, and the mineralization process. Based on the results above, a tentative mechanism for the catalytic performance of the Cu/Al2O3/g-C3N4 composite was proposed. In summary, the characteristics of high degradation rate constants, low ion leaching, and the excellent applicability in neutral and alkaline conditions prove the Cu/Al2O3/g-C3N4 composite to be a superior Fenton-like catalyst compared to many conventional ones.

Biodegradation Rate of Chloroethylene in Soil Environment

1992 ◽  
Vol 25 (11) ◽  
pp. 419-424 ◽  
Author(s):  
O. Yagi ◽  
H. Uchiyama ◽  
K. Iwasaki
Keyword(s):  
Soil Solution ◽  
Substrate Concentration ◽  
Material Balance ◽  
Field Soil ◽  
Soil Environment ◽  
Biodegradation Rate ◽  
Vegetable Field ◽  
Degradation Rates ◽  
Field Soils ◽  
Degradation Time

Degradation rates of PCE and TCE were determined in lotus, rice and vegetable field soils. The lotus field soil had the highest ability to degrade tetrachloroethylene(PCE) and trichloroethylene(TCE). The values of T50(50% degradation time) in L-1 lotus soil were 8 and 15 days for PCE and TCE under the substrate concentration of 5 µg in 50ml of soil solution. PCE was biologically transformed to TCE in all soils. The material balance of PCE depletion and TCE production were determined. The degradation rates of PCE and TCE were significantly influenced by temperature and substrate concentration.

scholarly journals Bloated Stars as BLR Clouds: Numeric Results

1994 ◽  
Vol 159 ◽  
pp. 437-437
Author(s):  
Tal Alexander ◽  
Hagai Netzer
Keyword(s):  
Mass Loss ◽  
Stellar Population ◽  
Line Emission ◽  
Distribution Functions ◽  
Solar Neighborhood ◽  
High Mass ◽  
Line Spectrum ◽  
Edge Density ◽  
Cloud Models ◽  
Wide Range

The ‘Bloated Stars Scenario’ proposes that AGN broad line emission originates in the winds or envelopes of bloated stars (BS) (see e.g. Kazanas 1989 and references therein). Its main advantage over BLR cloud models is the gravitational confinement of the gas and its major difficulty the large estimated number of BSs and the resulting high collisional and evolutionary mass loss rates (see e.g. Begelman & Sikura 1991). Previous work on this model did not include detailed calculations of the line spectrum, modeled solar neighborhood super giants (SG) and used very simplified stellar distribution functions for the nucleus. Here (Alexander & Netzer, 1993) we calculate the emission line ratios by applying a detailed numerical photoionization code (Rees, Netzer & Ferland, 1989) to the wind and by assuming a detailed nucleus model (Murphy, Cohn & Durisen, 1990). Allowing for the yet unknown effects of the AGN's extreme conditions on stars and stellar evolution, we study a wide range of simplified wind structures rather than confine ourselves to normal SGs. Our model consists of a spherically symmetric outflowing wind that emanates from the surface of the BS (R∗ = 1013 cm, M∗ = 0.8M⊙, M = 10−6M⊙/yr) whose size and edge density are determined by various processes: Comptonization by the central continuum source (calculated self consistently for our Lion = 1046 erg/s model continuum by the photoionization code), tidal disruption by the black hole (Mbh = 8 × 107M⊙) and the limit set by the assumption that the wind's mass ≤ 0.2M⊙. This results in a large range of wind sizes, from 1013 to 1016 cm. We find that the line emission spectrum is mainly determined by the conditions at the edge of the wind rather than by its internal structure. Comptonization results in a very high ionization parameter at the edge which produces an excess of unobserved broad high excitation forbidden lines. The finite mass constraint limits the wind's size, increases the edge density and thus improves the results. Studying power-law wind structures (v(R) = v∗(R/R∗)−α where v∗ is the wind's base velocity at the BS's surface), we find that slow, decelerating, mass-constrained flows (v∗ = 50 m/s, α = 0.5) with high gas densities (108 to 1012 cm−3) are as successful as cloud models in reproducing the overall observed line spectrum. The Mg II λ2798 and N V λ1240 lines are however under-produced in our models. The denser the winds, the more efficient they are as BLR clouds. By calculating the Lα emission from the wind we adjust the number of BSs so as to obtain the BLR's observed EW(Lα). We find that only ∼ 5 × 104 BSs with dense winds (v∗ = 50 m/s, α = 0.5) are required in the inner 1/3 pc (∼ 0.005 of the total stellar population). This small fraction approaches that of SGs in the solar neighborhood. The calculated mass loss from such a small number of BSs is consistent with the observational constraints. We find that the required number of BSs, and consequently their mass loss rate, are a very sensitive functions of the wind's density structure (a ∼ 104 factor between the slow v∗ = 50 m/s, α = 0.5 model and the fast v∗ = 50 km/s, α = −2 model). In particular, high mass loss rules out SG-like BSs (v∗ = 10 km/s, α = 0). We conclude that BSs with dense winds can reproduce the BLR line spectrum and be supported by the stellar population without excessive mass loss and collisional destruction rates. The question whether such hitherto unobserved stars actually exist in the BLR remains open.

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