378 research outputs found
Lute, Vihuela, and Early Guitar
Producción CientíficaLutes, guitars, and vihuelas were the principal plucked instruments in use in Europe until around
1800. Ancient forms of the lute existed in many parts of the ancient world, from Egypt and
Persia through to China. It appears to have become known in Europe, where its earliest
associations were with immigrants such as the legendary Persian lutenist Ziryab (b. c. 790–d.
852), who was established in Moorish Spain by 822. The origins of the various flat-backed
instruments that eventually became guitars are more difficult to trace. The vihuela is one such
instrument that evolved in the mid-15th century and was prolific in Spain and its dominions
throughout the 16th century and beyond. Very few plucked instruments, and only a handful of
fragmentary musical compositions, survive from before 1500. The absence of artifacts and
musical sources prior to 1500 has been a point of demarcation in the study of early plucked
instruments, although current research is seeking to explore the continuity of instrumental
practice across this somewhat artificial divide. In contrast, perhaps as many as thirty thousand
works—perhaps even more—for lute, guitar, and vihuela survive from the period 1500–1800.
The music and musical practices associated with them are not well integrated into general
histories of music. This is due in part to the use of tablature as the principal notation format until
about 1800, and also because writers of general histories of music have for the most part
ignored solo instrumental music in their coverage. (For example, the Oxford Anthology of
Western Music, Vol. 1 (2018), designed to accompany chapters 1–11 of Richard Taruskin’s
Oxford History of Western Music, does not contain a single piece of instrumental music prior to
Frescobaldi [1637]). Contrary to this marginalized image, lutes, vihuelas, and guitars were a
revered part of courtly musical culture until well into the 18th century, and constantly present in
urban contexts. After the development of basso continuo practice after 1600, plucked
instruments also became frequent in Christian church music, although the lute was widely
played by clerics of all levels, particularly during the Renaissance. It was also one of the
principal tools used by composers of liturgical polyphony, in part because tablature was the
most common way of writing music in score. From the beginning of music printing, printed
tablatures played a fundamental role in the urban dissemination of music originally for church
and court, and plucked instruments were used widely by all levels of society for both leisure and
pleasure. After 1800, the lute fell from use, the guitar was transformed into its modern form with
single strings, and tablature ceased to be the preferred notation for plucked instruments.Este trabajo forma parte del proyecto de investigación “La obra musical renacentista: fundamentos, repertorios y prácticas” HAR 2015-70181-P (MINECO/FEDER, UE
Reactive force fields – current status, needs, and challenges
Simulation-based predictive design of materials is a vital strategy towards fulfilling the directive posed by the National Materials Genome Initiative. The key ingredient in classical atomistic simulations is the interaction potential, or force field, which describes the energetic interplay between atomic constituents. Effective simulation-based materials design requires great flexibility in choosing the chemical composition of the material under development. It furthermore entails the ability to generate realistic atomistic structures of bulk materials, defects, and interfaces, in order to predict materials properties and behaviors accurately. Hence, the requirements for force fields used in atomistic simulations are: (1) computational efficiency, (2) adaptability, (3) transferability, and (4) accuracy. As to (1), to generate realistic structures containing extensive features and defects, simulations must include large numbers of atoms and be carried out over extensive periods of time. The more efficiently atomic interactions can be described and computed, the larger can simulate structures and the more detail can be accounted for in the temporal evolution of these structures. Indeed, in some cases structural developments include chemical reactions and phase transformations, which connotes requirement (2), i.e., force fields must be able to account for changes in bonding character, charge transfer, and coordination number change. Requirement (3) refers to ability of force fields to accommodate a wide variety of chemical species, the ensuing bonding types, and local structural symmetries. Finally, requirement (4) indicates that force fields not only need to accurately predict nearest-neighbor distances and bonding energies, but also properties that depend on higher order derivatives, e.g., vibrational properties, thermal expansion coefficients, etc. All these requirements call for the ability to develop force fields describing the interactions between exponentially expanding numbers of species combinations. The computational framework to accommodate this demand of force field features and parameterizations is currently sorely lacking. This presentation provides a summary of the current state-of-the-art, as well as examples of successes and shortcomings, and is intended to spur a dialogue concerning these demands and challenges
Some universal noiseless multiterminal source coding theorems
Fixed and variable-rate block and sliding-block weighted universal noiseless coding theorems are obtained which extend the Slepian-Wolf theorem for a single multiterminal source to a family of finite-alphabet, stationary, ergodic multiterminal sources
Lipoprotein Density Distributions Following Diet and Exercise Interventions
Atherosclerotic-related cardiovascular disease (ASCVD) claims the lives of over 600,000 Americans yearly. Current methodologies of assessment do not distinguish lipoprotein density distributions and instead measure lipoprotein cholesterol, with lowdensity lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDLC) of primary clinical relevance.
Furthermore, the distinction between the effects of diet and exercise interventions on lipoproteins is frequently indiscernible due to the effects of energy deficit induced by interventions. High- performance lipoprotein density profiling (HPLDP) provides a cost-effective way to rapidly assess the efficacy of diet or exercise interventions. The purpose of this study is to characterize density distribution of HDL subclasses in response to diet or exercise using HPLDP.
Eighty-eight untrained subjects (74% male, average age of 54 years) were pooled from two lifestyle intervention studies that met the inclusion criteria. Following 12 weeks of diet or exercise interventions (750 kcal expenditure or 750 kcal deficit), subjects lost an average of 3.72 kg weight (-3.9%), lost 3.9 kg of body fat (-11.6%), increased lean mass 0.62 kg (+1.1%), and reduced body fat percentage by 3.41% (-9.1%). Average absolute VO2 max increased 0.16 liters O2/min (+7.1%) (p<0.05). Several lipoprotein density distributions were significantly different (p<0.05) between diet and exercise interventions (expressed as percent change from baseline): triglyceride-rich lipoproteins (TRL) (-17.14 vs 19.65), low-density lipoprotein subfraction 5 (LDL5) (-26.06 vs 8.14), high-density lipoprotein subfraction 3b (HDL3b) (-21.24 vs -0.71), and high-density lipoprotein subfraction 3c (HDL3c) (-17.88 vs 7.94). To elucidate the effects of cardiorespiratory fitness, subjects were further divided into categories of increased absolute VO2 max and decreased absolute VO2 max, with no changes between groups at baseline. Associations between absolute VO2 max percent change on TRL, LDL-5, HDL-3b, and HDL-3c percent change remained significant after controlling for age, gender, and fat mass percent change. A regression equation was constructed from significant correlations and effectively predicted HDL-3c changes using absolute VO2 max measurements.
A significant linear relationship between improved absolute VO2 max and increased HDL-3c subfraction AUC exists; lipoprotein subfraction quantification may reveal positive effects of exercise overlooked using traditional clinical cholesterol assessment techniques
Lipoprotein Density Distributions Following Diet and Exercise Interventions
Atherosclerotic-related cardiovascular disease (ASCVD) claims the lives of over 600,000 Americans yearly. Current methodologies of assessment do not distinguish lipoprotein density distributions and instead measure lipoprotein cholesterol, with lowdensity lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDLC) of primary clinical relevance.
Furthermore, the distinction between the effects of diet and exercise interventions on lipoproteins is frequently indiscernible due to the effects of energy deficit induced by interventions. High- performance lipoprotein density profiling (HPLDP) provides a cost-effective way to rapidly assess the efficacy of diet or exercise interventions. The purpose of this study is to characterize density distribution of HDL subclasses in response to diet or exercise using HPLDP.
Eighty-eight untrained subjects (74% male, average age of 54 years) were pooled from two lifestyle intervention studies that met the inclusion criteria. Following 12 weeks of diet or exercise interventions (750 kcal expenditure or 750 kcal deficit), subjects lost an average of 3.72 kg weight (-3.9%), lost 3.9 kg of body fat (-11.6%), increased lean mass 0.62 kg (+1.1%), and reduced body fat percentage by 3.41% (-9.1%). Average absolute VO2 max increased 0.16 liters O2/min (+7.1%) (p<0.05). Several lipoprotein density distributions were significantly different (p<0.05) between diet and exercise interventions (expressed as percent change from baseline): triglyceride-rich lipoproteins (TRL) (-17.14 vs 19.65), low-density lipoprotein subfraction 5 (LDL5) (-26.06 vs 8.14), high-density lipoprotein subfraction 3b (HDL3b) (-21.24 vs -0.71), and high-density lipoprotein subfraction 3c (HDL3c) (-17.88 vs 7.94). To elucidate the effects of cardiorespiratory fitness, subjects were further divided into categories of increased absolute VO2 max and decreased absolute VO2 max, with no changes between groups at baseline. Associations between absolute VO2 max percent change on TRL, LDL-5, HDL-3b, and HDL-3c percent change remained significant after controlling for age, gender, and fat mass percent change. A regression equation was constructed from significant correlations and effectively predicted HDL-3c changes using absolute VO2 max measurements.
A significant linear relationship between improved absolute VO2 max and increased HDL-3c subfraction AUC exists; lipoprotein subfraction quantification may reveal positive effects of exercise overlooked using traditional clinical cholesterol assessment techniques
Anomalous thermomechanical properties and laser-induced densification of vitreous silica
The authors studied the anomalous behaviors of vitreous silica under the combined influence of high temperature and pressure, by using molecular dynamics simulations based on a charge-transfer three-body potential. Accordingly, anomalous properties, such as the minimum in the bulk modulus at ∼ 2–3 GPa∼2–3GPa and the negative thermal expansion while under pressure, are inherently connected to the ability of the glass to undergo irreversible densification. Their simulations reveal the structural features responsible for this behavior, as well as the extent to which these properties can be tailored through specific processing routes and hence create glass that is less susceptible to radiation damage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87797/2/141915_1.pd
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