Assessment of Data Quality: Errors of Measurement and Errors of Process

As projects progress from pilot studies with few simple variables and small samples, the research process as a whole becomes qualitatively more complex and subject to an array of contamination by errors and mistakes. Data usually undergo a series of manipulations (e.g., recording, computer entry, transmission) prior to final statistical analysis. The process, then, consists of numerous operations only ending with eventual statistical analysis and write-up. We present a means of estimating the impact of process error in the same terms as psychometric reliability and discuss the implications for reducing the impact of errors on overall data quality.     

Hypoxia-based strategies for angiogenic induction

Therapeutic angiogenesis promises to aid the healing and regeneration of tissues suffering from a compromised vascular supply. Ischaemia therapy has so far primarily focused on delivering isolated angiogenic growth factors. The limited success of these strategies in clinical trials, however, is increasingly forcing researchers to recognize the difficulties associated with trying to mimic the angiogenic process, due to its natural complexity. Instead, a new school of thought is gradually emerging, focusing on how to induce angiogenesis at its onset, by utilizing hypoxia, the primary angiogenic stimulus in physiological, as well pathological states. This shift in therapeutic approach is underlined by the realization of the importance of depressed HIF-1 α-mediated gene programming in non-healing ischemic tissues, which could explain their apparent habituation to chronic hypoxic stress and the limited capacity to generate adaptive angiogenesis. Hypoxia-based strategies, then effectively aim to override the habituated angiogenic cellular response, re-start the regenerative process and drive it to completion. Here we make a distinction between those strategies that utilize hypoxia in vitro as a preconditioning tool to optimize the angiogenic potential of tissue/cells before transplantation, vs. strategies that aim to induce hypoxia-induced signaling in vivo, directly, through pharmacological means or gene transfer. We then discuss possible future directions for the field, as it moves into the phase of clinical trials.     

Trace gas flux and the influence of short-term soil water and temperature dynamics in Australian sheep grazed pastures of differing productivity

Temperate pastures are often managed with P fertilizers and N₂-fixing legumes to maintain and increase pasture productivity which may lead to greater nitrous oxide (N₂O) emissions and reduced methane (CH₄) uptake. However, the diel and inter-daily variation in N₂O and CH₄ flux in pastures is poorly understood, especially in relation to key environmental drivers. We investigated the effect of pasture productivity, rainfall, and changing soil moisture and temperature upon short-term soil N₂O and CH₄ flux dynamics during spring in sheep grazed pasture systems in southeastern Australia. N₂O and CH₄ flux was measured continuously in a High P (23 kg P ha^?1 yr^?1) and No P pasture treatment and in a sheep camp area in a Low P (4 kg P ha^?1 yr^?1) pasture for a four week period in spring 2005 using an automated trace gas system. Although pasture productivity was three-fold greater in the High P than No P treatment, mean CH₄ uptake was similar (?6.3?±?SE 0.3 to ?8.6?±?0.4 μg C m^?2 hr^?1) as were mean N₂O emissions (6.5 to 7.9?±?0.8 μg N m^?2 hr^?1), although N₂O flux in the No P pasture did not respond to changing soil water conditions. N₂O emissions were greatest in the Low P sheep camp (12.4 μg?±?1.1 N m^?2 hr^?1) where there were also net CH₄ emissions of 5.2?±?0.5 μg C m^?2 hr^?1. There were significant, but weak, relationships between soil water and N₂O emissions, but not between soil water and CH₄ flux. The diel temperature cycle strongly influenced CH₄ and N₂O emissions, but this was often masked by the confounding covariate effects of changing soil water content. There were no consistently significant differences in soil mineral N or gross N transformation rates, however, measurements of substrate induced respiration (SIR) indicated that soil microbial processes in the highly productive pasture are more N limited than P limited after >20 years of P fertilizer addition. Increased productivity, through P fertilizer and legume management, did not significantly increase N₂O emissions, or reduce CH₄ uptake, during this 4 week measurement period, but the lack of an N₂O response to rainfall in the No P pasture suggests this may be evident over a longer measurement period. This study also suggests that small compacted and nutrient enriched areas of grazed pastures may contribute greatly to the overall N₂O and CH₄ trace gas balance.     

Analysis of the community structure of abyssal kinetoplastids revealed similar communities at larger spatial scales

Knowledge of the spatial scales of diversity is necessary to evaluate the mechanisms driving biodiversity and biogeography in the vast but poorly understood deep sea. The community structure of kinetoplastids, an important group of microbial eukaryotes belonging to the Euglenozoa, from all abyssal plains of the South Atlantic and two areas of the eastern Mediterranean was studied using partial small subunit ribosomal DNA gene clone libraries. A total of 1364 clones from 10 different regions were retrieved. The analysis revealed statistically not distinguishable communities from both the South-East Atlantic (Angola and Guinea Basin) and the South-West Atlantic (Angola and Brazil Basin) at spatial scales of 1000–3000 km, whereas all other communities were significantly differentiated from one another. It seems likely that multiple processes operate at the same time to shape communities of deep-sea kinetoplastids. Nevertheless, constant and homogenous environmental conditions over large spatial scales at abyssal depths, together with high dispersal capabilities of microbial eukaryotes, maintain best the results of statistically indistinguishable communities at larger spatial scales.     

Salmonella Phage S16 Tail Fiber Adhesin Features a Rare Polyglycine Rich Domain for Host Recognition

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Development of sturgeon catches in German and adjacent waters since 1980

The data of sturgeon catches in German and adjacent waters since 1980 have been collected from the major river systems and coastal waters in Germany and neighbouring countries. Over the past 10 years records on catches of exotic sturgeon species increasingly occur in the commercial and recreational fisheries, including the following species: Acipenser baerii, A. gueldenstaedtii as well as hybrids from different parental species such as H. huso x A. ruthenus, A. baerii x A. ruthenus. A total of 227 records are reported, including data on their distribution. Accidental or deliberate introductions of sturgeons have been mediated by aquaculture and/or petfish-industries. Their occurrence is discussed in relation to plans for the re-establishing of the native A. sturio.     

Polymer networks as actuator and sensor systems to be used for automation of biomedical devices]

Polymer networks are based on molecules which are covalently or physically connected in a three-dimensional network. In presence of an appropriate solvent these networks swell by solvent absorption to form gels. These gels, which are called hydrogels in case of water absorption, are able to change their volume by more than a hundred-fold. During the swelling or shrinking process the hydrogels perform a mechanical work. Their volume standardized working capacity can be ten-times larger than that of an electromagnet. Due to their simple design, miniaturisation properties, and their ability to realize many automatic sensor and actuator functions, smart hydrogels offer new solutions in biomedical technology.     

Die V?gel in der Heilkunde der alten Kulturv?lker. II

Ohne ZusammenfassungTeil I: J. f. O. 1925, p. 46–76.