Vibration Study for Consolidation of Portland Cement Concrete, Preprint, MLR-95-4, 1997

The Iowa Department of Transportation has discovered an increase in the occurrence of excessively vibrated portland cement concrete (PCC) pavements. The overconsolidation of PCC pavements has been observed in several projects across the state. Overconsolidation is also believed to be a factor in acceleration of premature deterioration of at least two pavement projects in Iowa. To address the problem, a research project in 1995 documented the vibratory practices of PCC slipform paving in Iowa in order to determine the effect of vibration on consolidation and air content of pavement. Paver speed, vibrator frequency, and air content relative to the location of the vibrator were studied. The study concluded that the Iowa Department of Transportation specification of 5,000 to 8,000 vibrations per minute (vpm) for slipform pavers is effective for normal paver speeds on the three projects that were examined. Excessive vibration was clearly identified on one project where a vibrator frequency of 12,000 vpm was discovered. When the paver speed was reduced to half the normal speed, hard air contents indicate that excessive vibration was beginning to occur in the localized area immediately surrounding the vibrator at a frequency of 8,000 vpm. The study also indicates that the radius of influence of the vibrators is smaller than has been claimed.

The use of uniaxial accelerometry for the assessment of physical-activity-related energy expenditure: a validation study against whole-body indirect calorimetry.

Assessing the total energy expenditure (TEE) and the levels of physical activity in free-living conditions with non-invasive techniques remains a challenge. The purpose of the present study was to investigate the accuracy of a new uniaxial accelerometer for assessing TEE and physical-activity-related energy expenditure (PAEE) over a 24 h period in a respiratory chamber, and to establish activity levels based on the accelerometry ranges corresponding to the operationally defined metabolic equivalent (MET) categories. In study 1, measurement of the 24 h energy expenditure of seventy-nine Japanese subjects (40 (SD 12) years old) was performed in a large respiratory chamber. During the measurements, the subjects wore a uniaxial accelerometer (Lifecorder; Suzuken Co. Ltd, Nagoya, Japan) on their belt. Two moderate walking exercises of 30 min each were performed on a horizontal treadmill. In study 2, ten male subjects walked at six different speeds and ran at three different speeds on a treadmill for 4 min, with the same accelerometer. O2 consumption was measured during the last minute of each stage and was expressed in MET. The measured TEE was 8447 (SD 1337) kJ/d. The accelerometer significantly underestimated TEE and PAEE (91.9 (SD 5.4) and 92.7 (SD 17.8) % chamber value respectively); however, there was a significant correlation between the two values (r 0.928 and 0.564 respectively; P<0.001). There was a strong correlation between the activity levels and the measured MET while walking (r(2) 0.93; P<0.001). Although TEE and PAEE were systematically underestimated during the 24 h period, the accelerometer assessed energy expenditure well during both the exercise period and the non-structured activities. Individual calibration factors may help to improve the accuracy of TEE estimation, but the average calibration factor for the group is probably sufficient for epidemiological research. This method is also important for assessing the diurnal profile of physical activity.

Neurophysiological changes during shortening osteotomies of the spine.

BACKGROUND CONTEXT: Kyphotic deformities with sagittal imbalance of the spine can be treated with spinal osteotomies. Those procedures are known to have a high incidence of neurological complications, in particular at the thoracic level. Motor evoked potentials (MEPs) have been widely used in helping to avoid major neurological deficits postoperatively. Previous reports have shown that a significant proportion of such cases present with important transcranial MEP (Tc-MEP) changes during surgery with some of them being predictive of postoperative deficits. PURPOSE: Our aim was to study Tc-MEP changes in a consecutive series of patients and correlate them with clinical parameters and radiological changes. STUDY DESIGN/SETTING: Retrospective case notes study from a prospective patient register. PATIENT SAMPLE: Eighteen patients undergoing posterior shortening osteotomies (nine at thoracic and nine at lumbar levels) for kyphosis of congenital, degenerative, inflammatory, or post-traumatic origin were included. OUTCOME MEASURES: Loss of at least 80% of Tc-MEP signal expressed as the area under the curve percentual change, of at least one muscle. METHODS: We studied the relation between outcome measure (80% Tc-MEP loss in at least one muscle group) and amount of posterior vertebral body shortening as well as angular correction measured on computed tomography scans, occurrence of postoperative deficits, intraoperative blood pressure at the time of the osteotomy, and hemoglobin (Hb) change. RESULTS: All patients showed significant Tc-MEP changes. In particular, greater than 80% MEP loss in at least one muscle group was observed in five of nine patients in the thoracic group and four of nine patients in the lumbar group. No surgical maneuver was undertaken as a result of this loss in an effort to improve motor responses other than verifying the stability of the construct and the extent of the decompression. Four patients developed postoperative deficits of radicular origin, three of them recovering fully at 3 months. No relation was found between intraoperative blood pressure, Hb changes, and Tc-MEP changes. Severity of Tc-MEP loss did not correlate with postoperative deficits. Shortening of more than 10 mm was linked to more severe Tc-MEP changes in the thoracic group. CONCLUSIONS: Transcranial MEP changes during spinal shortening procedures are common and do not appear to predict severe postoperative deficits. Total loss of Tc-MEP (not witnessed in our series) might require a more drastic approach with possible reversal of the correction and wake-up test.

Cómo elaborar, tutorizar y evaluar un trabajo de fin de máster

Los estudios de nivel superior en el marco de la Unión Europea se componen del Grado y del Postgrado (Másters y doctorados). Los Másters son titulaciones producto de una formación avanzada, multidisciplinar o especializada, dirigida a la consecución de logros académicos en profundidad, de especialidades profesionales o de iniciación a la investigación. Los estudios deMaster exigen la evaluación continua del proceso de aprendizaje que se concreta finalmente en el denominado Trabajo de Fin de Máster, verdadera piedra angular de la formación del estudiante. Ese trabajo final está pensado para evidenciar las competencias adquiridas a lolargo de todo el programa formativo y para demostrar el logro de los objetivos globales del aprendizaje. Es la prueba definitiva de la madurez y de la profesionalidad de una carrera hecha a conciencia...

Cómo elaborar, tutorizar y evaluar un trabajo de fin de máster

Los estudios de nivel superior en el marco de la Unión Europea se componen del Grado y del Postgrado (Másters y doctorados). Los Másters son titulaciones producto de una formación avanzada, multidisciplinar o especializada, dirigida a la consecución de logros académicos en profundidad, de especialidades profesionales o de iniciación a la investigación. Los estudios deMaster exigen la evaluación continua del proceso de aprendizaje que se concreta finalmente en el denominado Trabajo de Fin de Máster, verdadera piedra angular de la formación del estudiante. Ese trabajo final está pensado para evidenciar las competencias adquiridas a lolargo de todo el programa formativo y para demostrar el logro de los objetivos globales del aprendizaje. Es la prueba definitiva de la madurez y de la profesionalidad de una carrera hecha a conciencia...

Cómo elaborar, tutorizar y evaluar un trabajo de fin de máster

Los estudios de nivel superior en el marco de la Unión Europea se componen del Grado y del Postgrado (Másters y doctorados). Los Másters son titulaciones producto de una formación avanzada, multidisciplinar o especializada, dirigida a la consecución de logros académicos en profundidad, de especialidades profesionales o de iniciación a la investigación. Los estudios deMaster exigen la evaluación continua del proceso de aprendizaje que se concreta finalmente en el denominado Trabajo de Fin de Máster, verdadera piedra angular de la formación del estudiante. Ese trabajo final está pensado para evidenciar las competencias adquiridas a lolargo de todo el programa formativo y para demostrar el logro de los objetivos globales del aprendizaje. Es la prueba definitiva de la madurez y de la profesionalidad de una carrera hecha a conciencia...

Métodos indiretos para estimar a massa de forragem em pastos de Cynodon spp

O planejamento e o manejo em sistemas de produção animal em pastagens utilizam como informação essencial valores de massa e taxas de acúmulo de forragem. Este trabalho avaliou dois métodos, régua e prato ascendente, para estimar a massa de matéria seca de forragem em pastagens do gênero Cynodon, cultivares Florakirk, Tifton 85 e Coastcross. Os pastos foram mantidos a 5, 10, 15 e 20 cm de altura por meio de lotação contínua de ovinos em um delineamento experimental de blocos completos ao acaso com 4 repetições. Durante 12 meses foram geradas curvas de calibração do tipo y = a + bx entre altura do pasto (x), medida por meio de cada um dos dois métodos, e a massa de matéria seca de forragem correspondente (y), em kg ha-1. Os valores do intercepto (a) foram os mais influenciados por cultivar e época do ano. Houve variação apenas moderada nos valores do coeficiente angular (b). Essa variação esteve relacionada com modificações da estrutura do dossel forrageiro, particularmente a proporção de material morto. Os métodos não diferiram em precisão, porém o método do prato ascendente mostrou-se mais rápido e ágil. A calibração dos métodos deve ser específica para cada cultivar e realizada freqüentemente para que as equações geradas sejam precisas.

Cómo elaborar, tutorizar y evaluar un trabajo de fin de máster

Los estudios de nivel superior en el marco de la Unión Europea se componen del Grado y del Postgrado (Másters y doctorados). Los Másters son titulaciones producto de una formación avanzada, multidisciplinar o especializada, dirigida a la consecución de logros académicos en profundidad, de especialidades profesionales o de iniciación a la investigación. Los estudios deMaster exigen la evaluación continua del proceso de aprendizaje que se concreta finalmente en el denominado Trabajo de Fin de Máster, verdadera piedra angular de la formación del estudiante. Ese trabajo final está pensado para evidenciar las competencias adquiridas a lolargo de todo el programa formativo y para demostrar el logro de los objetivos globales del aprendizaje. Es la prueba definitiva de la madurez y de la profesionalidad de una carrera hecha a conciencia...

Linhagens de feijoeiro com resistência à antracnose selecionadas quanto a características agronômicas desejáveis

O objetivo deste trabalho foi identificar entre as linhagens de feijoeiro resistentes à antracnose, aquelas com alta produtividade, tipo de grãos Carioca, resistência à mancha-angular (Phaeoisariopsis griseola) e porte arbustivo. Foram avaliadas 256 linhagens oriundas de um programa de melhoramento genético por retrocruzamentos. Quatro experimentos foram conduzidos em três locais no Estado de Minas Gerais, em que foram avaliadas a produção e o tipo de grãos, o porte e a reação à mancha-angular. Observaram-se acentuadas diferenças genéticas entre as linhagens e, conseqüentemente, as herdabilidades foram também elevadas e propiciaram acentuados ganhos com a seleção. A maioria das correlações fenotípicas estimadas entre os caracteres não foi significativa, indicando a possibilidade de seleção de linhagens superiores em todos os fenótipos de interesse. Foram selecionadas cinco linhagens com alto potencial produtivo, grãos do tipo Carioca, porte arbustivo e maior nível de resistência à mancha-angular, sendo que duas delas possuem uma pirâmide de alelos de resistência à antracnose.

Vanishing Clams on an iberian beach: local consequences and global implication of accelerating loss of shells to tourism

Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of Spain. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. Concomitantly, abundance of mollusk shells along the shoreline decreased almost three-fold (2.62) and displayed a tight inverse correlation with tourist arrivals. A four-fold increase in tourist arrivals observed globally over the last 30 years has likely induced a comparable worldwide acceleration in shell removal from marine shorelines and exerted multiple negative (but currently unquantifiable) habitat changes that may include increased beach erosion, changes in carbon and calcium cycles, and decline in diversity and abundance of organisms dependent on shell availability.

The effect of mountain bike suspensions on vibrations and off-road uphill performance.

AIM: This study evaluates the effect of front suspension (FS) and dual suspension (DS) mountain-bike on performance and vibrations during off-road uphill riding. METHODS: Thirteen male cyclists (27+/-5 years, 70+/-6 kg, VO(2max)59+/-6 mL.kg(-1).min(-1), mean+/-SD) performed, in a random sequence, at their lactate threshold, an off-road uphill course (1.69 km, 212 m elevation gain) with both type of bicycles. Variable measured: a) VO(2) consumption (K4b2 analyzer, Cosmed), b) power output (SRM) c) gain in altitude and d) 3-D accelerations under the saddle and at the wheel (Physilog, EPFL, Switzerland). Power spectral analy- sis (Fourier) was performed from the vertical acceleration data. RESULTS: Respectively for the FS and DS mountain bike: speed amounted to 7.5+/-0.7 km.h(-1) and 7.4+/-0.8 km.h(-1), (NS), energy expenditure 1.39+/-0.16 kW and 1.38+/-0.18, (NS), gross efficiency 0.161+/-0.013 and 0.159+/-0.013, (NS), peak frequency of vibration under the saddle 4.78+/-2.85 Hz and 2.27+/-0.2 Hz (P<0.01) and median-frequency of vertical displacements of the saddle 9.41+/-1.47 Hz and 5.78+/-2.27 Hz (P<0.01). CONCLUSION: Vibrations at the saddle level of the DS bike are of low frequencies whereas those of the FS bike are mostly of high frequencies. In the DS bike, the torque produced by the cyclist at the pedal level may generate low frequency vibrations. We conclude that the DS bike absorbs more high frequency vibrations, is more comfortable and performs as well as the FS bicycle.

Com elaborar, tutoritzar i avaluar um treball de fi de màster

Els estudis de nivell superior en el marc de la Unió Europea es componen del Grau i delPostgrau (Màsters i Doctorats). Els Màsters són titulacions producte d’una formació avançada, multidisciplinària o especialitzada, dirigida a la consecució d’assoliments acadèmics enprofunditat, d’especialitats professionals o d’iniciació a la recerca. Els estudis de Màster exigeixen l’avaluació continuada del procés d’aprenentatge que es concreta finalment en el denominat Treball de Fi de Màster (TFM), vertadera pedra angular de la formació de l’estudiant. Aquest treball final està pensat per evidenciar les competències adquirides al llarg de tot elprograma formatiu i demostrar l’assoliment dels objectius globals de l’aprenentatge. És la prova definitiva de la maduresa i de la professionalitat d’una carrera feta a consciència...

Com elaborar, tutoritzar i avaluar um treball de fi de màster

Els estudis de nivell superior en el marc de la Unió Europea es componen del Grau i delPostgrau (Màsters i Doctorats). Els Màsters són titulacions producte d’una formació avançada, multidisciplinària o especialitzada, dirigida a la consecució d’assoliments acadèmics enprofunditat, d’especialitats professionals o d’iniciació a la recerca. Els estudis de Màster exigeixen l’avaluació continuada del procés d’aprenentatge que es concreta finalment en el denominat Treball de Fi de Màster (TFM), vertadera pedra angular de la formació de l’estudiant. Aquest treball final està pensat per evidenciar les competències adquirides al llarg de tot elprograma formatiu i demostrar l’assoliment dels objectius globals de l’aprenentatge. És la prova definitiva de la maduresa i de la professionalitat d’una carrera feta a consciència...

Com elaborar, tutoritzar i avaluar um treball de fi de màster

Els estudis de nivell superior en el marc de la Unió Europea es componen del Grau i delPostgrau (Màsters i Doctorats). Els Màsters són titulacions producte d’una formació avançada, multidisciplinària o especialitzada, dirigida a la consecució d’assoliments acadèmics enprofunditat, d’especialitats professionals o d’iniciació a la recerca. Els estudis de Màster exigeixen l’avaluació continuada del procés d’aprenentatge que es concreta finalment en el denominat Treball de Fi de Màster (TFM), vertadera pedra angular de la formació de l’estudiant. Aquest treball final està pensat per evidenciar les competències adquirides al llarg de tot elprograma formatiu i demostrar l’assoliment dels objectius globals de l’aprenentatge. És la prova definitiva de la maduresa i de la professionalitat d’una carrera feta a consciència...

Com elaborar, tutoritzar i avaluar um treball de fi de màster

Els estudis de nivell superior en el marc de la Unió Europea es componen del Grau i delPostgrau (Màsters i Doctorats). Els Màsters són titulacions producte d’una formació avançada, multidisciplinària o especialitzada, dirigida a la consecució d’assoliments acadèmics enprofunditat, d’especialitats professionals o d’iniciació a la recerca. Els estudis de Màster exigeixen l’avaluació continuada del procés d’aprenentatge que es concreta finalment en el denominat Treball de Fi de Màster (TFM), vertadera pedra angular de la formació de l’estudiant. Aquest treball final està pensat per evidenciar les competències adquirides al llarg de tot elprograma formatiu i demostrar l’assoliment dels objectius globals de l’aprenentatge. És la prova definitiva de la maduresa i de la professionalitat d’una carrera feta a consciència...