Homotopy hyperbolic 3-manifolds are hyperbolic

This paper introduces a rigorous computer-assisted procedure for analyzing hyperbolic 3-manifolds. This procedure is used to complete the proof of several long-standing rigidity conjectures in 3-manifold theory as well as to provide a new lower bound for the volume of a closed orientable hyperbolic 3-manifold

Magnetic Resonance Spectroscopy of the Brain in Alcohol Abuse.

Magnetic resonance (MR) technology produces data on brain structure and activity without relying on radiation or invasive surgery. Magnetic resonance imaging (MRI) creates images, and magnetic resonance spectroscopy (MRS) produces spectra based on the ability of atomic nuclei in tissues to absorb and release pulses of energy. MRS studies of alcohol in the brain reveal that only a portion of the alcohol in the brain can be detected by MR technology, suggesting that alcohol there exists in multiple pools. The pools not visible using MRS is hypothesized to be bound to cell membranes. Indirect evidence from MR studies of chronic alcohol abusers suggests that tolerance to alcohol's effects results in an increased rigidity of cell membranes that forces more alcohol to remain in the MR-visible pool (i.e., the pool not bound to membranes) compared with alcohol in the brains of nontolerant people

Hecken planen, pflanzen, pflegen. Eine praktische Anleitung für Landwirte

Das Merkblatt bietet interessierten Landwirten Entscheidungsgrundlagen für die Anlage von Hecken und vermittelt zahlreiche Tipps aus der Naturschutzberatung für die Planung, Pflanzung und Pflege dieser Gehölze

The Benefits of Local Forest Recreation in Austria and Its Dependence on Naturalness and Quietude

The benefits of local recreation in the State-owned forests in Austria (i.e., about 15% of all Austrian forests) are ascertained in this paper. A representative survey of households dealt with their local recreation, perceptions of and disturbances in forests. Total annual benefits of local recreation activities in State-owned forests, such as walking, hiking, cycling and wildlife observation, amount to about EUR 500 per person. Based on the respondents’ valuation of the degree of naturalness and quietude, as well as the options of forest management, the current management increases recreation benefits by EUR 13 per person through increased naturalness, and EUR 1.30 per person and year through increased quietude. Emphasis was placed on the benefits of the current management regime of multifunctional forestry compared to the benefits of a baseline scenario that was drafted specifically for this study, assuming higher levels of lumbering up to the limits allowed by existing nature conservation and forestry laws. The results suggest that forest management has a higher impact on recreational benefits through the naturalness of forests than through reducing artificial noise. A more sustainable forest management could further increase the benefits people derive from both naturalness and lower levels of artificial noise

Water entry of a flat elastic plate at high horizontal speed

The two-dimensional problem of an elastic-plate impact onto an undisturbed surface of water of infinite depth is analysed. The plate is forced to move with a constant horizontal velocity component which is much larger than the vertical velocity component of penetration. The small angle of attack of the plate and its vertical velocity vary in time, and are determined as part of the solution, together with the elastic deflection of the plate and the hydrodynamic loads within the potential flow theory. The boundary conditions on the free surface and on the wetted part of the plate are linearized and imposed on the initial equilibrium position of the liquid surface. The wetted part of the plate depends on the plate motion and its elastic deflection. To determine the length of the wetted part we assume that the spray jet in front of the advancing plate is negligible. A smooth separation of the free-surface flow from the trailing edge is imposed. The wake behind the moving body is included in the model. The plate deflection is governed by Euler’s beam equation, subject to free–free boundary conditions. Four different regimes of plate motion are distinguished depending on the impact conditions: (a) the plate becomes fully wetted; (b) the leading edge of the plate touches the water surface and traps an air cavity; (c) the free surface at the forward contact point starts to separate from the plate; (d) the plate exits the water. We could not detect any impact conditions which lead to steady planing of the free plate after the impact. It is shown that a large part of the total energy in the fluid–plate interaction leaves the main bulk of the liquid with the spray jet. It is demonstrated that the flexibility of the plate may increase the hydrodynamic loads acting on it. The impact loads can cause large bending stresses, which may exceed the yield stress of the plate material. The elastic vibrations of the plate are shown to have a significant effect on the fluid flow in the wake

Cigarette smoking history is associated with poorer recovery in multiple neurocognitive domains following treatment for an alcohol use disorder.

Cigarette smoking is associated with neurocognitive dysfunction in various populations, including those seeking treatment for an alcohol use disorder (AUD). This study compared the rate and extent of recovery on measures of processing speed, executive functions, general intelligence, visuospatial skills and working memory in treatment-seeking alcohol dependent individuals (ALC) who were never-smokers (nvsALC), former-smoker (fsALC), and active smokers (asALC), over approximately 8 months of abstinence from alcohol. Methods: ALC participants were evaluated at approximately 1 month of abstinence (AP1; n = 132) and reassessed after 8 months of sobriety (AP2; n = 54). Never-smoking controls (CON; n = 33) completed a baseline and follow-up (n = 19) assessment approximately 9 months later. Domains evaluated were executive functions, general intelligence, processing speed, visuospatial skills and working memory; a domain composite was formed from the arithmetic average of the foregoing domains. nvsALC showed greater improvement than fsALC, asALC and CON on most domains over the AP1-AP2 interval. fsALC demonstrated greater recovery than asALC on all domains except visuospatial skills; fsALC also showed greater improvements than CON on general intelligence, working memory and domain composite. asALC did not show significant improvement on any domain over the AP1-AP2 interval. At 8 months of abstinence, asALC were inferior to CON and nvsALC on multiple domains, fsALC performed worse than nvsALC on several domains, but nvsALC were not different from CON on any domain. Our results provide robust evidence that smoking status influenced the rate and extent of neurocognitive recovery between 1 and 8 months of abstinence in this ALC cohort. Chronic smoking in AUD likely contributes to the considerable heterogeneity observed in neurocognitive recovery during extended abstinence. The findings provide additional strong support for the benefits of smoking cessation and the increasing clinical movement to offer smoking cessation resources concurrent with treatment for AUD