Pulse-pressure variation and hemodynamic response in patients with elevated pulmonary artery pressure: a clinical study

Pulse-pressure variation (PPV) due to increased right ventricular afterload and dysfunction may misleadingly suggest volume responsiveness. We aimed to assess prediction of volume responsiveness with PPV in patients with increased pulmonary artery pressure.

Pulse pressure variation and volume responsiveness during acutely increased pulmonary artery pressure: an experimental study

We found that pulse pressure variation (PPV) did not predict volume responsiveness in patients with increased pulmonary artery pressure. This study tests the hypothesis that PPV does not predict fluid responsiveness during an endotoxin-induced acute increase in pulmonary artery pressure and right ventricular loading.

Mountains and Climate Change: A Global Concern

Editor's note: The text of this article originally appeared as the final chapter of a brochure entitled Mountains and Climate Change—From Understanding to Action, prepared at the Centre for Development and Environment, University of Bern, Switzerland, for presentation by the Swiss Agency for Development and Cooperation (SDC) at a side event at the United Nations Climate Change Conference in Copenhagen on 12 December 2009. Chapters of the brochure deal with various aspects of climate change and its impact in mountain regions. In light of the significance of the Copenhagen COP 15 conference, the editors of this publication believe MRD's readers will be interested in reading this summary written from the perspective of Swiss researchers and development experts. The full brochure may be viewed and downloaded at www.cde.unibe.ch/Research/MA_Re.asp

Effects of timbre and tempo change on memory for music

We investigated the effects of different encoding tasks and of manipulations of two supposedly surface parameters of music on implicit and explicit memory for tunes. In two experiments, participants were first asked to either categorize instrument or judge familiarity of 40 unfamiliar short tunes. Subsequently, participants were asked to give explicit and implicit memory ratings for a list of 80 tunes, which included 40 previously heard. Half of the 40 previously heard tunes differed in timbre (Experiment 1) or tempo (Experiment 2) in comparison with the first exposure. A third experiment compared similarity ratings of the tunes that varied in timbre or tempo. Analysis of variance (ANOVA) results suggest first that the encoding task made no difference for either memory mode. Secondly, timbre and tempo change both impaired explicit memory, whereas tempo change additionally made implicit tune recognition worse. Results are discussed in the context of implicit memory for nonsemantic materials and the possible differences in timbre and tempo in musical representations.

Seasonal variation and sources of low molecular weight organic acids in precipitation in the rural area of Anshun

Low mol. wt. (LMW) org. acids are important and ubiquitous chem. constituents in the atm. A comprehensive study of the chem. compn. of pptn. was carried out from June 2007 to June 2008 at a rural site in Anshun, in the west of Guizhou Province, China. During this period, 118 rainwater samples were collected and the main LMW carboxylic acids were detd. using ion chromatog. The av. pH of rainwater was 4.89 which is a typical acidic value. The most abundant carboxylic acids were formic acid (vol. wt. mean concn.: 8.77 μmol L-1) and acetic acid (6.90 μmol L-1), followed by oxalic acid (2.05 μmol L-1). The seasonal variation of concns. and wet deposition fluxes of org. acids indicated that direct vegetation emissions were the main sources of the org. acids. Highest concns. were obsd. in winter and were ascribed to the low winter rainfall and the contribution of other air pollution sources northeast of the study area. The ratio of formic and acetic acids in the pptn. ([F/A]T) was proposed as an indicator of pollution source. This suggested that the pollution resulted from direct emissions from natural or anthropogenic sources. Comparison with acid pptn. in other urban and rural areas in Guizhou showed that there was a decreasing contribution of LMW org. acids to free acidity and all anions in rainwater from urban to remote rural areas. Consequently, it is necessary to control emissions of org. acids to reduce the frequency of acid rain, esp. in rural and remote areas. [on SciFinder(R)]

Measuring Correlation Between HIV Sequence Variation and Disease Stage of HIV-Infected Individuals

With a virus such as Human Immunodeficiency Virus (HIV) that has infected millions of people worldwide, and with many unaware that they are infected, it becomes vital to understand how the virus works and how it functions at the molecular level. Because there currently is no vaccine and no way to eradicate the virus from an infected person, any information about how the virus interacts with its host greatly increases the chances of understanding how HIV works and brings scientists one step closer to being able to combat such a destructive virus. Thousands of HIV viruses have been sequenced and are available in many online databases for public use. Attributes that are linked to each sequence include the viral load within the host and how sick the patient is currently. Being able to predict the stage of infection for someone is a valuable resource, as it could potentially aid in treatment options and proper medication use. Our approach of analyzing region-specific amino acid composition for select genes has been able to predict patient disease state up to an accuracy of 85.4%. Moreover, we output a set of classification rules based on the sequence that may prove useful for diagnosing the expected clinical outcome of the infected patient.

Scales of Impact: Settlement History and Landscape Change in the Gordion Region, Central Anatolia

The expansion of agriculture in the Near East during the middle Holocene significantly altered the physical landscape. However, the relationship between the scale of agriculture and the magnitude and timing of the environmental impacts is not well known. The Gordion Regional Survey provides a novel dataset to compare settlement density during archaeological periods to rates of environmental disruption. Sediment samples from alluvial cores directly date the environmental disruption, which can be matched to period-specific settlement intensities in the watershed as constructed from archaeological survey ceramics. Degradation rates rose sharply within a millennium of the earliest Chalcolithic occupation. Early Bronze Age (EBA) land use induced the greatest rates of environmental degradation, although settlement density was relatively low on the landscape. The degradation rate subsequently decreased to one-third its early peak by the Iron Age, even as settlement intensity climbed. This trajectory reveals how complex interaction effects can amplify or subdue the responses of the landscape-land use system. Prior to settlement, landscape soil reservoirs were highly vulnerable, easily tipped by early agricultural expansion. Subsequent reduced rates of erosion are tied both to changes in sociopolitical organization and to depletion of the vulnerable soil supply.