997 resultados para Forest influences
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PURPOSE: It is unclear whether sociocultural and socioeconomic factors are directly linked to type 2 diabetes risk in overweight/obese ethnic minority children and adolescents. This study examines the relationships between sociocultural orientation, household social position, and type 2 diabetes risk in overweight/obese African-American (n = 43) and Latino-American (n = 113) children and adolescents. METHODS: Sociocultural orientation was assessed using the Acculturation, Habits, and Interests Multicultural Scale for Adolescents (AHIMSA) questionnaire. Household social position was calculated using the Hollingshead Two-Factor Index of Social Position. Insulin sensitivity (SI), acute insulin response (AIRG) and disposition index (DI) were derived from a frequently sampled intravenous glucose tolerance test (FSIGT). The relationships between AHIMSA subscales (i.e., integration, assimilation, separation, and marginalization), household social position and FSIGT parameters were assessed using multiple linear regression. RESULTS: For African-Americans, integration (integrating their family's culture with those of mainstream white-American culture) was positively associated with AIRG (β = 0.27 ± 0.09, r = 0.48, P < 0.01) and DI (β = 0.28 ± 0.09, r = 0.55, P < 0.01). For Latino-Americans, household social position was inversely associated with AIRG (β = -0.010 ± 0.004, r = -0.19, P = 0.02) and DI (β = -20.44 ± 7.50, r = -0.27, P < 0.01). CONCLUSIONS: Sociocultural orientation and household social position play distinct and opposing roles in shaping type 2 diabetes risk in African-American and Latino-American children and adolescents.
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In 2005, Holy and Guo advanced the idea that male mice produce ultrasonic vocalizations (USV) with some features similar to courtship songs of songbirds. Since then, studies showed that male mice emit USV songs in different contexts (sexual and other) and possess a multisyllabic repertoire. Debate still exists for and against plasticity in their vocalizations. But the use of a multisyllabic repertoire can increase potential flexibility and information, in how elements are organized and recombined, namely syntax. In many bird species, modulating song syntax has ethological relevance for sexual behavior and mate preferences. In this study we exposed adult male mice to different social contexts and developed a new approach of analyzing their USVs based on songbird syntax analysis. We found that male mice modify their syntax, including specific sequences, length of sequence, repertoire composition, and spectral features, according to stimulus and social context. Males emit longer and simpler syllables and sequences when singing to females, but more complex syllables and sequences in response to fresh female urine. Playback experiments show that the females prefer the complex songs over the simpler ones. We propose the complex songs are to lure females in, whereas the directed simpler sequences are used for direct courtship. These results suggest that although mice have a much more limited ability of song modification, they could still be used as animal models for understanding some vocal communication features that songbirds are used for.
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The possibility of encouraging the growth of forests as a means of sequestering carbon dioxide has received considerable attention, partly because of evidence that this can be a relatively inexpensive means of combating climate change. But how sensitive are such estimates to specific conditions? We examine the sensitivity of carbon sequestration costs to changes in critical factors, including the nature of management and deforestation regimes, silvicultural species, relative prices, and discount rates. (C) 2000 Academic Press.
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A cursory glance at cello works by English composers during the twentieth- century yields an unexpected relationship to Russian musicians, history, culture, and religion. One must wonder how this connection or "Russian thread" came to be. When considering the working relationship of Benjamin Britten and Mstislav Rostropovich, the likelihood of such a connection is tangible, since their deeply personal friendship influenced Britten's music for cello. However, what is perhaps more interesting is the emergence of connections to Russia in the works of other English composers of the twentieth-century, featuring works from 1913-1996. This project was conceived after close study and analysis of Benjamin Britten's Third Suite for Solo Cello, Op. 87 (1971). Britten's inclusion of Russian folk tunes and an Orthodox Church hymn signaled the penetrating presence of Russian elements in his works. Britten's First Suite for Solo Cello, Op. 72, Third Suite for Cello, Op. 87, and Sonata for Piano and Cello in C, Op. 65 are presented in this project. Further exploration of works for cello by English composers unveiled similar connections to Russia. The Sonata for Cello and Piano of Frank Bridge is likened to Russian romanticism and the Cello Sonata of Sergei Rachmaninoff. William Walton's Cello Concerto was written for the Russian-American cellist Gregor Piatigorsky. Wake Up ...and die is John Tavener's deeply spiritual work, which is rooted in his Russian Orthodoxy. John Ireland, influenced by models of French and Russian Impressionism, contributed works colored with Russian folk influences, of which his Piano Trio No. 2 is an example. Finally, Arnold Bax traveled to Russia as a young man and his Folk Tale and Legend Sonata are imbued with the spirit of Russian folk music and architecture. This dissertation project is comprised of three recitals featuring English works for cello connected by a "Russian Thread." All events took place on the campus of University of Maryland, College Park: Recital #1 on December 4, 2011 in the Gildenhorn Recital Hall of the Clarice Smith Performing Arts Center, Recital #2 on February 11,2012, and Recital #3 on April 15, 2012, both in the Ulrich Recital Hall.
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© 2015 Published by Elsevier B.V.Throughout the southern US, past forest management practices have replaced large areas of native forests with loblolly pine plantations and have resulted in changes in forest response to extreme weather conditions. However, uncertainty remains about the response of planted versus natural species to drought across the geographical range of these forests. Taking advantage of a cluster of unmanaged stands (85-130year-old hardwoods) and managed plantations (17-20year-old loblolly pine) in coastal and Piedmont areas of North Carolina, tree water use, cavitation resistance, whole-tree hydraulic (Ktree) and stomatal (Gs) conductances were measured in four sites covering representative forests growing in the region. We also used a hydraulic model to predict the resilience of those sites to extreme soil drying. Our objectives were to determine: (1) if Ktree and stomatal regulation in response to atmospheric and soil droughts differ between species and sites; (2) how ecosystem type, through tree water use, resistance to cavitation and rooting profiles, affects the water uptake limit that can be reached under drought; and (3) the influence of stand species composition on critical transpiration that sets a functional water uptake limit under drought conditions. The results show that across sites, water stress affected the coordination between Ktree and Gs. As soil water content dropped below 20% relative extractable water, Ktree declined faster and thus explained the decrease in Gs and in its sensitivity to vapor pressure deficit. Compared to branches, the capability of roots to resist high xylem tension has a great impact on tree-level water use and ultimately had important implications for pine plantations resistance to future summer droughts. Model simulations revealed that the decline in Ktree due to xylem cavitation aggravated the effects of soil drying on tree transpiration. The critical transpiration rate (Ecrit), which corresponds to the maximum rate at which transpiration begins to level off to prevent irreversible hydraulic failure, was higher in managed forest plantations than in their unmanaged counterparts. However, even with this higher Ecrit, the pine plantations operated very close to their critical leaf water potentials (i.e. to their permissible water potentials without total hydraulic failure), suggesting that intensively managed plantations are more drought-sensitive and can withstand less severe drought than natural forests.
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The musical period of Neoclassicism began in the 1920's, between the first and second world wars. It was initiated by French composers and eventually spread to other countries. One of the most important themes to emerge from the movement was to escape from the formless, rather emotional music of the Romantic era and instead, emphasize balance, order, objectivity and clarity in musical form. Many popular clarinet repertoires are enjoyed by performers and listeners because the music is enjoyable to play and easy to listen to. In particular, classically influenced clarinet music is quite interesting because it features musical elements from both the past and contemporary musical styles. For instance, some composers have integrated preexisting, more traditional styles of composition with lighter styles of modern culture such as popular music and Jazz. It is difficult to discover purely neoclassical clarinet repertoires even though many composers created their pieces during the neoclassical era. What we most commonly find are both neoclassical and non-neoclassical influences in compositions from that time period. Thus, I aim to trace the influence of neoclassicism in selected clarinet repertoires that exist today. It is my hope that increased awareness and knowledge about accessible clarinet music may encourage the general public to develop a deeper interest in a wider sphere of clarinet music, beyond what is considered popular today. The works performed and discussed in this dissertation are the following: (Recital I) Duo Concertante by Darius Milhaud; Sonata by Leonard Bernstein; Sonata for Two Clarinets by Francis Poulenc; Duos for Flute and Clarinet, Op. 34 by Robert Muczynski; Dance Preludes by Witold Lutoslawski, (Recital II) Sonatine by Arthur Honegger; Time pieces by Robert Muczynski; Suite for Clarinet, Violin and Piano by Darius Milhaud; Sonate for Clarinet, Flute and Piano by Maurice Emmanuel; Tarantelle for Flute, Clarinet and Piano, Op. 6 by Camille Saint-Saëns, (Recital III) Sonatina by Joseph Horovitz; Suite from L'histoire du Soldat for Clarinet, Violin and Piano by Igor Stravinsky; Contrasts for Clarinet, Violin and Piano by Béla Bartók The recitals that took place on December 1, 2012 and on April 25, 2013 were performed in the Ulrich Recital Hall of the Clarice Performing Arts Center in College Park, Maryland. The recital that took place on November 2, 2013 was performed at the Gildenhorn Recital Hall of the same performing arts center.
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p.37-45
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Data from a hilly forest study site at Batang Ule, Sumatra, are organized into 30 100-m × 10-m subplots lying perpendicular to the line of maximal topographic gradient, from the valley to the plateau/ridge. The following methodological question is addressed: what species diversity measures are best used in order to reveal the ecologically distinct regions in the site. The main tool used to answer this question is the α-diversity curve (Hα). Graphical examination of tree and species densities, and α-diversity curves identifies an anomalous species diversity behaviour of the ‘ridge above the slope’ subplots which may have implications on land-facet class definitions. Factor analysis of the α-diversity curves indicates that the diversity space is two-dimensional: i.e. two diversity measures are sufficient to characterize the site; the species density (H0), and the Berger-Parker index (H[infty infinity]). In the two-dimensional diversity-space three distinct species diversity groups are found which relate to the topographic gradient at the Batang Ule site. The results are compared with those for a flat homogeneous site at Pasirmayang, Sumatra. The implications of the results on land-classifications in species-diversity mapping and conservation strategy are discussed.
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Data from three forest sites in Sumatra (Batang Ule, Pasirmayang and Tebopandak) have been analysed and compared for the effects of sample area cut-off, and tree diameter cut-off. An 'extended inverted exponential model' is shown to be well suited to fitting tree-species-area curves. The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 35 for Tebopandak (tree diameter >10cm). It would seem that in terms of species carrying capacity, Tebopandak and Pasirmayang are rather similar, and both less diverse than the hilly Batang Ule site. In terms of conservation policy, this would mean that rather more emphasis should be put on conserving hilly sites on a granite substratum. For Pasirmayang with tree diameter >3cm, the asymptotic species number estimate is 567, considerably higher than the estimate of 387 species for trees with diameter >10cm. It is clear that the diameter cut-off has a major impact on the estimate of the species carrying capacity. A conservative estimate of the total number of tree species in the Pasirmayang region is 632 species! In sampling exercises, the diameter cut-off should not be chosen lightly, and it may be worth adopting field sampling procedures which involve some subsampling of the primary sample area, where the diameter cut-off is set much lower than in the primary plots.