Acoustically based fetal heart rate monitor

The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer

Airborne Electronic Ultra-Fast Scanning Spectrometer

An all- electronic scanning spectrometer is described which is capable of scanning the 0.6 to 1 u spectral region at scan rates of up to 10,200 scans /second at a resolution of better than 15 $. An image dissector photoelectron multiplier tube is used as the detection device. The minimum detectable signal of the system is Zess than 1 x 10 -E w cm-2 2-1 at 0.8 u. The instrument occupies a volume of less than half a cubic foot and is designed for operation in a KC -135 aircraft. Video magnetic tape recording is used, and a digital read -out method has been developed so that the data can be programmed into a computer

Passive fetal monitoring sensor

An ambulatory, passive sensor for use in a fetal monitoring system is discussed. The invention is comprised of a piezoelectric polymer film, combined with a metallic mounting plate fastened to a belt, and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted by a fetus inside an expectant mother. Additionally, the monitor will filter out pressure pulses arising from other sources, such as the maternal heart

Low number of mitochondrial pseudogenes in the chicken (Gallus gallus) nuclear genome: implications for molecular inference of population history and phylogenetics

BACKGROUND: Mitochondrial DNA has been detected in the nuclear genome of eukaryotes as pseudogenes, or Numts. Human and plant genomes harbor a large number of Numts, some of which have high similarity to mitochondrial fragments and thus may have been inadvertently included in population genetic and phylogenetic studies using mitochondrial DNA. Birds have smaller genomes relative to mammals, and the genome-wide frequency and distribution of Numts is still unknown. The release of a preliminary version of the chicken (Gallus gallus) genome by the Genome Sequencing Center at Washington University, St. Louis provided an opportunity to search this first avian genome for the frequency and characteristics of Numts relative to those in human and plants. RESULTS: We detected at least 13 Numts in the chicken nuclear genome. Identities between Numts and mitochondrial sequences varied from 58.6 to 88.8%. Fragments ranged from 131 to 1,733 nucleotides, collectively representing only 0.00078% of the nuclear genome. Because fewer Numts were detected in the chicken nuclear genome, they do not represent all regions of the mitochondrial genome and are not widespread in all chromosomes. Nuclear integrations in chicken seem to occur by a DNA intermediate and in regions of low gene density, especially in macrochromosomes. CONCLUSION: The number of Numts in chicken is low compared to those in human and plant genomes, and is within the range found for most sequenced eukaryotic genomes. For chicken, PCR amplifications of fragments of about 1.5 kilobases are highly likely to represent true mitochondrial amplification. Sequencing of these fragments should expose the presence of unusual features typical of pseudogenes, unless the nuclear integration is very recent and has not yet been mutated. Metabolic selection for compact genomes with reduced repetitive DNA and gene-poor regions where Numts occur may explain their low incidence in birds

Single mitochondrial gene barcodes reliably identify sister-species in diverse clades of birds

Abstract Background DNA barcoding of life using a standardized COI sequence was proposed as a species identification system, and as a method for detecting putative new species. Previous tests in birds showed that individuals can be correctly assigned to species in ~94% of the cases and suggested a threshold of 10× mean intraspecific difference to detect potential new species. However, these tests were criticized because they were based on a single maternally inherited gene rather than multiple nuclear genes, did not compare phylogenetically identified sister species, and thus likely overestimated the efficacy of DNA barcodes in identifying species. Results To test the efficacy of DNA barcodes we compared ~650 bp of COI in 60 sister-species pairs identified in multigene phylogenies from 10 orders of birds. In all pairs, individuals of each species were monophyletic in a neighbor-joining (NJ) tree, and each species possessed fixed mutational differences distinguishing them from their sister species. Consequently, individuals were correctly assigned to species using a statistical coalescent framework. A coalescent test of taxonomic distinctiveness based on chance occurrence of reciprocal monophyly in two lineages was verified in known sister species, and used to identify recently separated lineages that represent putative species. This approach avoids the use of a universal distance cutoff which is invalidated by variation in times to common ancestry of sister species and in rates of evolution. Conclusion Closely related sister species of birds can be identified reliably by barcodes of fixed diagnostic substitutions in COI sequences, verifying coalescent-based statistical tests of reciprocal monophyly for taxonomic distinctiveness. Contrary to recent criticisms, a single DNA barcode is a rapid way to discover monophyletic lineages within a metapopulation that might represent undiscovered cryptic species, as envisaged in the unified species concept. This identifies a smaller set of lineages that can also be tested independently for species status with multiple nuclear gene approaches and other phenotypic characters

Stability of trusses by graphic statics.

This paper presents a graphical method for determining the linearized stiffness and stability of prestressed trusses consisting of rigid bars connected at pinned joints and which possess kinematic freedoms. Key to the construction are the rectangular areas which combine the reciprocal form and force diagrams in the unified Maxwell-Minkowski diagram. The area of each such rectangle is the product of the bar tension and the bar length, and this corresponds to the rotational stiffness of the bar that arises due to the axial force that it carries. The prestress stability of any kinematic freedom may then be assessed using a weighted sum of these areas. The method is generalized to describe the out-of-plane stability of two-dimensional trusses, and to describe three-dimensional trusses in general. The paper also gives a graphical representation of the 'product forces' that were introduced by Pellegrino and Calladine to describe the prestress stability of trusses

Reconstructing palaeoflyways of the late Pleistocene and early Holocene Red Knot Calidris canutus

Bird migration systems must have changed dramatically during the glacial–interglacial cycles of the Pleistocene and as novel habitats became available since the last glacial maximum. This study combines molecular dating of population divergence times with a review of polar-centred palaeovegetation and intertidal habitats world-wide to present a hypothesis for the evolution of Red Knot Calidris canutus flyways. Divergence dates from coalescent analysis of mitochondrial control region sequences indicate that C. c. canutus diverged from the most recent common ancestor (MRCA) of Red Knots about 20000 (95% CI 60000–4000) years ago. About 12000 (95% CI 45000–3500) years ago this MRCA diverged into two lineages, now represented by the North American breeding C. c. roselaari, C. c. rufa and C. c. islandica and the Siberian breeding C. c. piersmai and C. c. rogersi, respectively. Divergence times of these two Siberian breeding subspecies are about 6500 (95% CI 25000–1000) years ago, and populations of the North American breeding subspecies are estimated to have diverged within about the last 1000 years. These divergence times suggest that all ancestral populations of knots emerged within the last glacial period of the Pleistocene via an eastward expansion into North America. This scenario implies that, contrary to contemporary opinions, C. c. islandica was not recently derived from C. c. canutus despite the fact that they are morphologically similar and that their contemporary migration routes overlap in the Wadden Sea. Instead, C. c. islandica is most closely related to the other North American breeding subspecies C. c. roselaari and C. c. rufa. Thus, C. c. islandica only recently pioneered its current migration route to Europe, following the amelioration of winter conditions in the Wadden Sea and the formation of staging habitat in Iceland. This implies that, in Red Knots at least, the Greenland/Iceland migratory route was established very recently from breeding grounds in the Americas to wintering grounds in Europe and not vice versa as previously believed.