Polarized antiquark flavor asymmetry: Pauli blocking vs. the pion cloud

The flavor asymmetry of the unpolarized antiquark distributions in the proton, dbar(x) - ubar(x) > 0, can qualitatively be explained either by Pauli blocking by the valence quarks, or as an effect of the pion cloud of the nucleon. In contrast, predictions for the polarized asymmetry Delta_ubar(x) - Delta_dbar(x) based on rho meson contributions disagree even in sign with the Pauli blocking picture. We show that in the meson cloud picture a large positive Delta_ubar(x) - Delta_dbar(x) is obtained from pi-N - sigma-N interference-type contributions, as suggested by chiral symmetry. This effect restores the equivalence of the 'quark' and 'meson' descriptions also in the polarized case.Comment: 4 pages, revtex, 3 eps figure

Human Transformations of the Swedish Boreal Forestry

A successful production-oriented forestry has influenced nearly all Swedish boreal forests. Accordingly, the standing volume has increased continuously since official data became available in the 1920s. On the other hand, there is very little natural forest left, except in the sub-alpine area. In the pre-industrial era, probably the most important human impact on the Swedish boreal forests (around two-thirds of the country's productive forest land may be considered as boreal) was the conversion of forests to arable land, e.g. on sediments around lakes and in river valleys. In the 19th century, fire suppression had become effective in the whole area. Until the beginning of the present century, the iron industry in the southern part of boreal Sweden needed large quantities of wood and charcoal. To ensure this supply, forest management based on the clear-felling harvest system was introduced in the middle of the 19th century. Today, most sites in this region carry their second or third rotation. North of the mining district, i.e. the major part of boreal Sweden, a logging frontier moved northwards during the 19th century. Initially, large diameter Scots pine was cut in a purely exploitive manner. The standing volume was substantially reduced, probably from a level higher than today's. This selective cutting was replaced by the clear-felling system around 1950, when the state launched a restoration program to regenerate low-stocked sites. Since 1950, around 44% of the productive forest land in boreal Sweden has been cleared. Intensive regeneration measures and stand treatments have generated rather homogeneous stands dominated by conifers. Since 1970, lodgepole pine, introduced from western Canada, has been planted on 4% of the productive forest land in boreal Sweden. These radical changes in the Swedish boreal forests have heavily altered the natural processes and structures at different spatial scales. Fragments of woodland key habitats containing red-listed plants (mainly cryptogams as fungi, lichens, and mosses) and animals (mainly insects) are embedded in a matrix of well-managed forests. From a biodiversity point of view, the most important management measures probably are to increase the number and quality of undisturbed forests and the amounts of coarse woody debris and deciduous trees, and to reintroduce fire

Motor recovery following capsular stroke

The functional anatomy of motor recovery was studied by assessing motor function quantitatively in 23 patients following capsular or striatocapsular stroke. While selective basal ganglia lesions (caudate and/or putamen exclusively) did not affect voluntary movements of the extremities, lesions of the anterior (plus caudate/putamen) or posterior limb of the internal capsule led to an initially severe motor impairment followed by excellent recovery, hand function included. In contrast, lesions of the posterior limb of the internal capsule in combination with damage to lateral thalamus compromised motor outcome. In experimental tracing of the topography of the internal capsule in macaque monkeys, we found axons of primary motor cortex passing through the middle third of the posterior limb of the internal capsule. Axons of premotor cortex (dorsolateral and post-arcuate area 6) passed through the capsular genu, and those of supplementary motor area (mesial area 6) through the anterior limb. Small capsular lesion can therefore disrupt the output of functionally and anatomically distinct motor areas selectively. The clinically similar motor deficits with a similar course of functional restitution following disruption of these different descending motor pathways indicate a parallel operation of cortical motor areas. They may have the further capability of substituting each other functionally in the process of recovery from hemiparesis

American Linguistics And The Teaching Of English

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98286/1/j.1467-1770.1955.tb00828.x.pd

The Expression Of The Future *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98324/1/j.1467-1770.1956.tb01207.x.pd

Preparation Of Teaching Materials, Practical Grammars, And Dictionaries, Especially For Foreign Languages *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98288/1/j.1467-1770.1959.tb01128.x.pd

The Periphrastic Use Of Shall And Will In Modern English

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98215/1/j.1467-1770.1956.tb00858.x.pd

Have As A Function Word

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98375/1/j.1467-1770.1948.tb00883.x.pd

As We See It

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98352/1/j.1467-1770.1948.tb01361.x.pd