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1.
Ecotoxicol Environ Saf ; 202: 110865, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32570103

RESUMEN

Crop production in acid soils is facing enormous challenges due to low soil quality associated with an increase in the acidification rate and aluminum toxicity. Despite comprehensive prior work with biochar application on nutrient availability and crop productivity in acid soils, little information is available about the recommendation or standardization of biochar application rates that are more suitable for soil fertility improvement under different soil environments (physico-chemical properties) for maximizing the benefits of biochar applications and minimizing the potential environmental risk. Thus, the objective of this study was to investigate the effectiveness of poultry litter (PL) and poultry litter biochar (PLB) in ameliorating the fertility of acid soils through incubation and pot experiments. The soil was amended with different materials as follows; lime (1 g kg-1), PL (5, 10 and 15 g kg-1) and PLB (5, 10 and 15 g kg-1) along with control (non-amended). A pot experiment was also conducted using similar treatments to observe the responses of maize crop to the different amendments. The results indicated an increase in the pH and a decrease in exchangeable acidity in lime, PL and PLB amended soils. Lower soil pH, base cations and soil available phosphorus (P), and higher exchangeable acidity were found in control than the amended soils. Compared to PL and lime, PLB achieved greater increase rate in soil pH and reduction rate in soil exchangeable acidity with increased soil exchangeable base cations. An increase in soil available calcium (Ca) was observed in the lime treatment, while in PL and PLB treatments, there was an increase in soil available Ca, magnesium (Mg), potassium (K) and P. Application of the amendments increased availability of nitrogen (N), P, K, Ca and Mg relative to the control for maize in the pot experiment. When PL and PLB amendments were compared, it was found that the PLB was the best choice for the amelioration of acid soils as well as nutrient uptake by maize plants. It is suggested that application of PLB at the rate of 15 g kg-1 is suitable for maize growth in acid soils.


Asunto(s)
Carbón Orgánico , Restauración y Remediación Ambiental/métodos , Zea mays/fisiología , Ácidos , Animales , Calcio , Compuestos de Calcio , Magnesio , Nitrógeno , Óxidos , Fósforo , Potasio , Aves de Corral , Suelo/química , Contaminantes del Suelo/análisis , Zea mays/crecimiento & desarrollo
2.
Environ Sci Pollut Res Int ; 22(13): 9965-75, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25666472

RESUMEN

The acidity of Ultisols (pH <5) is detrimental to crop production. Technologies should be explored to promote base saturation and liming effect for amelioration of Ultisol pH. Column leaching experiments were conducted to investigate the amelioration effects of canola straw (CS) and peanut straw (PS) in single treatment and in combination whether with alkaline slag (AS) or with lime on Ultisol profile acidity. The treatment without liming materials was set as control, and the AS and lime in single treatment are set for comparison. Results indicated that all the liming materials increase soil profile pH and soil exchangeable base cations at the 0-40-cm depth, except that the lime had amelioration effect just on 0 to 15-cm profile. The amelioration effect of the liming materials on surface soil acidity was mainly dependent on the ash alkalinity in organic materials or acid neutralization capacity of inorganic materials. Specific adsorption of sulfate (SO4(2-)) or organic anions, decarboxylation of organic acids/anions, and the association of H(+) with organic anions induced a "liming effect" of crop residues and AS on subsoil acidity. Moreover, SO4(2-) and chloride (Cl(-)) in PS, CS, and AS primarily induced base cations to move downward to subsoil and exchange with exchangeable aluminum (Al(3+)) and protons (H(+)). These anions also promoted the exchangeable Al to leach out of the soil profile. The CS was more effective than PS in decreasing soil acidity in the subsoil, which mainly resulted from higher sulfur (S) and Cl content in CS compared to PS. The CS combined with AS was the better amendment choice in practical agricultural systems.


Asunto(s)
Compuestos de Calcio/química , Óxidos/química , Preparaciones de Plantas/química , Suelo/química , Adsorción , Agricultura , Aluminio/aislamiento & purificación , Silicatos de Aluminio/química , Arachis/química , Brassicaceae/química , Arcilla , Concentración de Iones de Hidrógeno , Sulfatos/análisis
3.
Chaos ; 24(3): 033130, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25273210

RESUMEN

Positron-acoustic (PA) solitary waves (SWs) and double layers (DLs) in four-component plasmas consisting of immobile positive ions, mobile cold positrons, and superthermal (kappa distributed) hot positrons and electrons are investigated both numerically and analytically by deriving Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and Gardner equations along with their DLs solutions using the reductive perturbation method. It is examined that depending on the plasma parameters, the K-dV SWs, Gardner SWs, and DLs support either compressive or rarefactive structures, whereas mK-dV SWs support only compressive structure. It is also found that the presence of superthermal (kappa distributed) hot positrons and hot electrons significantly modify the basic features of PA SWs as well as PA DLs. Besides, the critical number density ratio of hot positrons and cold positrons play an important role in the polarity of PA SWs and DLs. The implications of our results in different space as well as laboratory plasma environments are briefly discussed.

4.
Chaos ; 23(1): 013147, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23556984

RESUMEN

A rigorous theoretical investigation has been performed on dust-acoustic (DA) solitary structures in an unmagnetized dusty plasma, consisting of negatively charged mobile dust grains, Boltzmann distributed electrons, and nonthermally distributed ions of two distinct temperatures. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV) and Gardner equations, and their solitary waves (SWs) and double layer (DL) (in case of Gardner equation) solutions are derived by using the reductive perturbation technique. The basic features of the DA Gardner solitons (GSs) and DLs are studied analytically as well as numerically. It has been observed that the GSs significantly differ from K-dV and mK-dV solitons, and only positive potential DLs exist in the system. It is also studied that two-temperature nonthermal ions significantly modify the nature and basic properties of the DA SWs. The present investigation can be very effective for understanding and studying the nonlinear characteristics of the DA waves in laboratory and space dusty plasmas.


Asunto(s)
Acústica , Polvo , Dinámicas no Lineales , Temperatura , Simulación por Computador , Electrones , Iones , Movimiento (Física) , Análisis Numérico Asistido por Computador , Sonido , Factores de Tiempo
6.
Psychooncology ; 10(6): 541-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11747066

RESUMEN

The purpose of this study is to examine the relationship between psychological factors, regional brain activity and natural killer cell activity (NKA). Eight patients with malignant diseases were studied by FDG-PET under a resting condition. NKA and degree of anxiety and depression were measured using Taylor's manifest anxiety scale (MAS) and Zung's self-rating depression scale (SDS). Linear correlation of NKA and psychological measures to the regional brain metabolism in cancer patients was examined using statistical parametric mapping (SPM). Positive linear correlation between NKA and regional metabolic rate ratios was identified in the visual association cortex, anterior cingulate gyrus (CG) and sensorimotor area, and negative correlation was identified in the inferolateral prefrontal cortex (ILPFC), prefrontal cortex (PFC), orbitofrontal cortex (OFC) and anterior temporal cortex. Positive linear correlation to the MAS score was identified in the visual association cortex, anterior CG, primary sensorimotor area and the posterior parietal cortex, and negative correlation was detected in the ILPFC, PFC, OFC and anterior temporal cortex. The NKA and MAS scores positively correlated with each other (p<0.001). The result might serve as supporting data for a hypothesis that psycho-immune interaction is also mediated by the cerebral cortex and limbic system.


Asunto(s)
Ansiedad , Encéfalo/metabolismo , Células Asesinas Naturales/inmunología , Neoplasias/inmunología , Neoplasias/psicología , Tomografía Computarizada de Emisión , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Depresión , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Escala de Ansiedad Manifiesta , Persona de Mediana Edad , Neoplasias/diagnóstico por imagen
7.
Nucleic Acids Res Suppl ; (1): 21-2, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-12836244

RESUMEN

We synthesized various 5'-triphosphates of C5-substituted 2'-deoxyuridine derivatives bearing methylene linker at C5-alpha position. We examined whether the C5-substituted 2'-deoxyuridine 5'-triphosphates (dUTP) can work as a substrate for the modified DNA synthesis by PCR. We found that only KOD dash DNA polymerase, a thermostable DNA polymerase from extremely thermophilic archaeum, accepted the modified substrates in place of TTP for PCR forming the corresponding modified DNAs. On the other hand, no other DNA polymerase could accept these TTP analogues.


Asunto(s)
ADN/biosíntesis , Oligodesoxirribonucleótidos/biosíntesis , Reacción en Cadena de la Polimerasa , Secuencia de Bases , ADN/química , ADN Polimerasa Dirigida por ADN/metabolismo , Nucleótidos de Desoxiuracil/síntesis química , Nucleótidos de Desoxiuracil/química , Oligodesoxirribonucleótidos/química
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