Environment Suitable (environment + suitable)

Distribution by Scientific Domains

Selected Abstracts

A Model-Based Method for an Online Diagnostic Knowledge-Based System

EXPERT SYSTEMS, Issue 3 2001
Chrissanthi Angeli
Fault diagnosis is very important for modern production technology and has received increasing theoretical and practical attention during the last few years. This paper presents a model-based diagnostic method for industrial systems. An online, real-time, deep knowledge based fault detection system has been developed by combining different development environments and tools. The system diagnoses, predicts and compensates faults by coupling symbolic and numerical data in a new environment suitable for the interaction of different sources of knowledge and has been successfully implemented and tested on a real hydraulic system. [source]

Female zebra finches compromise clutch temperature in energetically demanding incubation conditions

Andreas Nord
Summary 1.,Avian embryos depend on the incubating parent to provide a thermal environment suitable for embryogenesis, but as the maintenance of optimal incubation temperatures is energetically costly, an incubating bird often must trade off embryonic investment against self-maintenance. 2.,We manipulated the energetic cost of incubation in female zebra finches (Taeniopygia guttata Vieillot) by varying ambient temperature and clutch size during nocturnal incubation and recorded the corresponding effects on incubation metabolic rate and clutch temperature. 3.,Females increased their night-time incubation metabolic rate more than twofold when incubating at 10 C compared to when incubating close to thermoneutrality (28 C). Furthermore, clutch enlargement caused females to elevate their metabolic rate with 28% per additional egg added to the clutch. 4.,However, despite spending more energy, females did not fully cover the increased costs of incubation, because clutch temperature decreased with decreasing ambient temperature and increasing clutch size. 5.,These findings suggest that parental investment in incubation can be energetically constrained and sometimes result in clutch temperatures below the optimal level for embryonic development, at least during nocturnal incubation. [source]

Novel dimer structure of a membrane-bound protease with a catalytic Ser,Lys dyad and its linkage to stomatin

Hideshi Yokoyama
Membrane-bound proteases are involved in various regulatory functions. A previous report indicates that the N-terminal region of PH1510 (1510-N) from the hyperthermophilic archaeon Pyrococcus horikoshii is a serine protease with a catalytic Ser,Lys dyad (Ser97 and Lys138), and specifically cleaves the C-terminal hydrophobic region of the p-stomatin PH1511. According to the crystal structure of the wild-type 1510-N in dimeric form, the active site around Ser97 is in a hydrophobic environment suitable for the hydrophobic substrates. This article reports the crystal structure of the K138A mutant of 1510-N at 2.3, resolution. The determined structure contains one molecule per asymmetric unit, but 1510-N is active in dimeric form. Two possible sets of dimer were found from the symmetry-related molecules. One dimer is almost the same as the wild-type 1510-N. Another dimer is probably in an inactive form. The L2 loop, which is disordered in the wild-type structure, is significantly kinked at around A-138 in the K138A mutant. Thus Lys138 probably has an important role on the conformation of L2. [source]

Continuous perfusion microfluidic cell culture array for high-throughput cell-based assays

Paul J. Hung
Abstract We present for the first time a microfluidic cell culture array for long-term cellular monitoring. The 10 10 array could potentially assay 100 different cell-based experiments in parallel. The device was designed to integrate the processes used in typical cell culture experiments on a single self-contained microfluidic system. Major functions include repeated cell growth/passage cycles, reagent introduction, and real-time optical analysis. The single unit of the array consists of a circular microfluidic chamber, multiple narrow perfusion channels surrounding the main chamber, and four ports for fluidic access. Human carcinoma (HeLa) cells were cultured inside the device with continuous perfusion of medium at 37C. The observed doubling time was 1.4 0.1 days with a peak cell density of ,2.5*105 cells/cm2. Cell assay was demonstrated by monitoring the fluorescence localization of calcein AM from 1 min to 10 days after reagent introduction. Confluent cell cultures were passaged within the microfluidic chambers using trypsin and successfully regrown, suggesting a stable culture environment suitable for continuous operation. The cell culture array could offer a platform for a wide range of assays with applications in drug screening, bioinformatics, and quantitative cell biology. 2004 Wiley Periodicals, Inc. [source]

Palaeovegetational and palaeoenvironmental trends in the summit of the Guaiquinima massif (Venezuelan Guayana) during the Holocene,

Valent Rull
Abstract The summits of the table mountains (tepuis) from the Neotropical Guayana region are remote environments suitable for palaeoecological studies with evolutionary, biogeographical and palaeoclimatic implications. Here, using palynological analyses of two radiocarbon-dated peat bogs from a tepui summit, the Holocene palaeovegetational trends are reconstructed, and related to possible forcing factors. Because of the pristine character of the Guaiquinima summit, the recorded palaeoenvironmental changes are probably due to natural causes, which makes them valuable archives of the natural component of climatic change at a millennial time scale. The sequence begins with pioneer communities or meadows similar to present-day ones, between about 8.4 and 4.5,ky BP. After this date, and until about 2,kyr BP the expansion of gallery forests suggests an increase in precipitation, documented also at regional (Neotropical) level. Between ca. 2,kyr BP and the last century, gallery forests are replaced by forests characteristic of the upper Guaiquinima altitudes, coinciding with a regional phase of reduced moisture. The present-day meadows, established relatively quickly during the last century, substituted the former upland forests. In the locality studied, the main controlling factor of the vegetation during the Holocene seems to have been the moisture balance. In contrast to other tepui summits, there is no clear evidence for changes linked to temperature oscillations. This could be due to the elevation of the site, far from any characteristic ecological boundary, that makes it insensitive to this parameter. Copyright 2005 John Wiley & Sons, Ltd. [source]

Sensitivity of tropical forests to climate change in the humid tropics of north Queensland

David W. Hilbert
Abstract An analysis using an artificial neural network model suggests that the tropical forests of north Queensland are highly sensitive to climate change within the range that is likely to occur in the next 50,100 years. The distribution and extent of environments suitable for 15 structural forest types were estimated, using the model, in 10 climate scenarios that include warming up to 1C and altered precipitation from ,10% to +20%. Large changes in the distribution of forest environments are predicted with even minor climate change. Increased precipitation favours some rainforest types, whereas decreased rainfall increases the area suitable for forests dominated by sclerophyllous genera such as Eucalyptus and Allocasuarina. Rainforest environments respond differentially to increased temperature. The area of lowland mesophyll vine forest environments increases with warming, whereas upland complex notophyll vine forest environments respond either positively or negatively to temperature, depending on precipitation. Highland rainforest environments (simple notophyll and simple microphyll vine fern forests and thickets), the habitat for many of the region's endemic vertebrates, decrease by 50% with only a 1C warming. Estimates of the stress to present forests resulting from spatial shifts of forest environments (assuming no change in the present forest distributions) indicate that several forest types would be highly stressed by a 1C warming and most are sensitive to any change in rainfall. Most forests will experience climates in the near future that are more appropriate to some other structural forest type. Thus, the propensity for ecological change in the region is high and, in the long term, significant shifts in the extent and spatial distribution of forests are likely. A detailed spatial analysis of the sensitivity to climate change indicates that the strongest effects of climate change will be experienced at boundaries between forest classes and in ecotonal communities between rainforest and open woodland. [source]