866 research outputs found
Rationalising the Interaction of Tax and social Security: Part II: Fundamental Reform Options.
No full textThis paper considers more major structural reforms which could address such problems in a systematic manner, and allow the implementation of a designed set of effective tax rates (ETRs) for social security clients and taxpayers.TAX POLICY ; SOCIAL SECURITY
Rationalising the Interaction ofTax and Social Security: PartI: Specific Problem Areas.
No full textThis paper considers options for addressing problems in the way the tax and social security systems interact.TAX POLICY ; SOCIAL SECURITY
Sustainable Ethanol Production from Common Reed (Phragmites australis) through Simultaneuos Saccharification and Fermentation
No full textPhragmites australis (common reed) is a perennial grass that grows in wetlands or near inland waterways. Due to its fast-growing properties and low requirement in nutrients and water, this arboreal variety is recognized as a promising source of renewable energy although it is one of the least characterized energy crops. In this experiment, the optimization of the bioethanol production process from Phragmites australis was carried out. Raw material was first characterized according to the standard procedure (NREL) to evaluate its composition in terms of cellulose, hemicellulose, and lignin content. Common reed was pretreated by steam explosion process at three different severity factor (R0) values. The pretreatment was performed in order to reduce biomass recalcitrance and to make cellulose more accessible to enzymatic attack. After the pretreatment, a water insoluble substrate (WIS) rich in cellulose and lignin and a liquid fraction rich in pentose sugars (xylose and arabinose) and inhibitors were collected and analyzed. The simultaneous saccharification and fermentation (SSF) of the WIS was performed at three different solid loadings (SL) 10%, 15%, 20% (w/w). The same enzyme dosage, equal to 20% (g enzyme/g cellulose), was used for all the WIS loadings. The efficiency of the whole process was evaluated in terms of ethanol overall yield (g ethanol/100 g raw material). The maximum ethanol overall yields achieved were 16.56 and 15.80 g ethanol/100 g RM dry basis for sample AP10 and sample AP4.4, respectively. The yields were reached working at lower solid loading (10%) and at the intermediate LogR0 value for the former and at intermediate solid loading (15%) and high LogR0 value for the latter, respectively
Fractionation of Lignocellulosic Residues Coupling Steam Explosion and Organosolv Treatments Using Green Solvent γ-Valerolactone
No full textA two-step fractionation of lignocellulosic residues of Phragmites australis in its main components (cellulose-pulp, soluble hemicellulose sugars, and lignin) is described, based on the biomass-derived solvent γ-valerolactone (GVL). The solvent used is an excellent substitute for traditional organic solvents as it is not toxic, it is renewable, and it can be recycled after the extraction process. Prior the GVL-organosolv extraction process, a steam explosion pretreatment was performed in order to break up the tight lignocellulosic structure and partially depolymerise hemicellulose into soluble sugars, making lignin easier to be solubilised. Three common extraction techniques were compared: soxhlet, closed vessel microwave-assisted, and open vessel on a hotplate stirrer. The two-step approach resulted in a cellulose-rich solid, water-soluble hemicellulose sugars and lignin-rich GVL liquor which was further purified for lignin isolation. The two best resulting pulps presented a high cellulose content (75.47% and 78.68%) starting from 38.13% and a content of lignin down to 11.96% and 13.09% starting from 23.02%. Almost all hemicellulose was removed with a final content of 0.72% and 2.20% starting from 20.5%
Rationalising the interaction of tax and social security - Part I: specific problem areas
No full textThe government’s tax package (hereafter referred to as “NTS”: a New Tax System for Australia) addresses a number of issues for families raised in Ingles’ 1997 CEPR Discussion Paper “Low Income Traps for Working Families”, but leaves others unresolved and falls short of full-scale structural reform. For example, it reduces family payment tapers, but the new taper continue to overlap with those under the Youth Allowance Scheme. It reduces the many different family payments to two (three counting childcare), but allows these payments to abate simultaneously in some situations, which will particularly impact on the work decisions of a spouse. This paper proposes measures that address these specific problem areas. However another approach is a full-scale structural reform. The measures herein are all forms of harmonisation of the tax and social security systems; but ultimately more radical options (integration or full separation) might yield a system that is more rational and can produce a designed structure of effective tax rates. These options – along with the option of a Negative Income Tax – are canvassed in a separate paper – Part II (Discussion Paper 424)
David ricardo .
No full textDavid Ricardo dio un gran impulso e hizo las contribuciones más importantes a la Teoría clásica fundada por Adam Smith, la cual cimentó el enfoque ortodoxo de los problemas económicos y de la política económica hasta el último cuarto del siglo XIX. Analizó sistemáticamente la economía en términos de unos cuantos principios fundamentales y estudió las consecuencias de diversas medidas de política económica dentro del marco teórico por él establecido convirtiendo de esta manera, a la economía en la primera ciencia social. A continuación intentaremos la compleja tarea de dar una visión sucinta de la vasta y polifacética obra del gran autor ingles, puntualizando en la problemática económica que se acaba de mencionar y, además, deteniéndonos un poco en la vida del economista y en los acontecimientos teóricos que sucedieron a ella
Aprendizaje colaborativo y su influencia en la expresión oral en ingles 2° B secundaria – I.E. “David León” - Contumaza 2018
No full textEl presente trabajo de investigación se titula “APRENDIZAJE COLABORATIVO Y SU INFLUENCIA EN LA EXPRESION ORAL EN INGLES 2° B SECUNDARIA - I.E. “DAVID LEON” - CONTUMAZA 2018”, y tuvo como objetivo general conocer en qué medida el aprendizaje colaborativo influye en la expresión oral en inglés en los estudiantes de 2º B de secundaria de la I.E. “David León” – Contumazá 2018".
Para el estudio de la investigación se utilizó el diseño pre-experimental, por lo que se trabajó con un solo grupo, pre y post test y la población estuvo conformada por 55 estudiantes de 2 grado de educación secundaria, cuya muestra ha sido seleccionada de manera intencional eligiendo la sección “B”, la cual constó de 16 estudiantes, a quienes se les aplicó un pre test, antes de emplear la estrategia del Aprendizaje Colaborativo; posteriormente se desarrollaron las 10 sesiones de aprendizaje colaborativo, y finalmente se aplicó un post test.
La razón del trabajo fue hacer uso de una estrategia didáctica innovadora, como es el aprendizaje colaborativo con el fin de desarrollar la expresión oral del idioma inglés en los estudiantes mencionados, y a la vez brindarles la motivación requerida para hacer su aprendizaje más significativo y divertido.
Para la obtención de datos se empleó las técnicas de procesamiento y análisis, así como la estadística descriptiva; finalmente para la obtención e interpretación de los resultados, se hizo uso de cuadros, gráficos y distribución porcentual.
Los resultados del análisis de datos obtenidos, mostraron que el aprendizaje colaborativo influyó significativamente en la expresión oral en inglés en estudiantes de 2°B secundaria de la I.E. “David León” – Contumazá 2018, debido a que las puntuaciones posteriores a la prueba evidenciaron una puntuación media creciente de 7.94 (pre test) a 16.13 (post test), rindiendo de esta manera una diferencia altamente significativa (p < 0,05).Tesi
One-pot lignin extraction and modification in γ-valerolactone from steam explosion pre-treated lignocellulosic biomass
No full textA one-pot route to extract and chemically modify lignin from a pre-treated Phragmites australis lignocellulosic biomass is proposed herein. The lignocellulosic biomass was first pre-treated through steam explosion at two different severity factors. Lignin was then extracted from the steam-exploded biomasses through a microwave-assisted organosolv extraction method, solely using γ-valerolactone as solvent. The most severe steam explosion condition yielded a delignification of 78%. Morphological analysis, spectroscopic investigation and thermal characterization showed that essentially pure lignin was extracted through this process. Lignin was then chemically modified in the γ-valerolactone extraction solution, through acetylation and Mannich condensation. This work provides proof-of-evidence that pure lignin can be solvent-extracted in high yields from a pre-treated biomass without the addition of any further chemicals and successfully modified in a one-pot route through a cleaner process. The modified lignin could be used as building block for the development of novel bio-based polymer materials
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