Heavy metals and arsenic in the biosphere

Non-Peer Reviewe

Does biased gene conversion influence polymorphism in the circumsporozoite protein-encoding gene of Plasmodium vivax?

Variation between North Korean and Latin American isolates in the circumsporozoite (CS) protein encoding gene of the human malaria parasite Plasmodium vivax was studied. Polymorphic positions are confined to the central tandemly repeated sequences. Nucleotide substitutions in the tandem repeats produce variants; these substituted positions within the repeat array tend to be conserved between genes. The North Korean CS gene has a short insertion after the repeats encoding a 4-amino acid repeat (Ala-Gly-Gly-Asn) not found in the New World P. vivax genes. This sequence is found both flanking and within the tandem repeats of the CS genes of several strains of the Southeast Asian simian malaria parasite, Plasmodium cynomolgi. The intraspecific conservation of positions of variants within tandem repeat arrays and the interspecific conservation of probably ancestral repeat motifs at the end of these arrays are consistent with the occurrence of nonreciprocal genetic exchanges between the tandem repeats of these genes. However, a striking asymmetry in strand nucleotide composition within the tandem repeats of all CS genes leads us to suggest that biased correction of heteroduplexes formed during recombination plays a role in the evolution of these genes

Managing Insect and Mite Pests of Texas Corn.

20 p

Doppler colour flow mapping of fetal intracerebral arteries in the presence of central nervous system anomalies

The adjunctive role of Doppler colour flow mapping in the evaluation of intracerebral morphology and arterial blood flow in the presence of normal and abnormal central nervous system morphology was determined. A total of 59 fetuses with suspected central nervous system pathology between 14 and 37 weeks of gestation was studied (median 31 weeks). One hundred and one fetuses with normal central nervous system anatomy between 14 and 37 weeks (median 19 weeks) served as controls. Visualisation of blood flow in one or more intracerebral arterial vessels was successful in more than 80% of normal fetuses. For the anterior, middle and posterior cerebral artery, the percentages were 63%, 89% and 45%, respectively, at 14–25 weeks and 74%, 100% and 55%, respectively, at 26–37 weeks of gestation. Intracerebral arterial flow identification was attempted in 52/59 (88%) affected fetuses. Identification of blood flow in one or more intracerebral arterial vessels was successful in (77%) fetuses. End-diastolic flow velocities were present in at least one of the intracerebral arteries in fetuses, absent in one case of hydrocephaly and raised in the presence of an intracerebral vascular tumour. Doppler colour flow mapping seems to provide only limited additional information on intracranial structural pathology

Internal Gravity Wave Detection During The 21 August 2017 Total Solar Eclipse

Total solar eclipses supply both visual captivation and a controlled meteorological experiment through a sudden decrease in solar radiation. However, along with commonly expected changes in weather conditions, prior research suggests an adjustment of atmospheric dynamics caused by both a decrease in local incident solar radiation and the Moon’s sweeping shadow across the Earth at supersonic speed. The result is the potential production of internal gravity waves, which transfer both energy and momentum vertically to and from the upper levels of the atmosphere. A series of radiosondes were launched before, during, and after the 21 August 2017 eclipse in Batesburg, South Carolina. Observations of internal gravity waves and low level meteorological conditions are reported. Finally, the eclipse event is compared to model output which accounts for the solar eclipse. On this occasion, it is concluded that internal gravity waves were sourced from both localized convection to the southeast of the field site location as well as the total solar eclipse. Furthermore, the wave period of the proposed solar eclipse induced internal gravity waves fall in line with previous studies

Prenatal diagnosis by ultrasound in pregnancies at risk for autosomal recessive polycystic kidney disease

Abstract In 15 pregnancies at risk of the autosomal recessive type of polycystic kidney disease (ARPKD), there were six recurrences (40%), five of which were diagnosed prenatally between 17 and 26 weeks (mean, 22 weeks). In the remaining affected case, normal kidney size and echogenicity were still present at 30 weeks of gestation. Fetal kidney enlargement and increased echogenicity are the key ultrasonographic signs for the detection of ARPKD. Absent fetal bladder filling and oligohydramnios were only documented in two of the six affected pregnancies. The variability in onset, the intrafamilial variability and the limitations of excluding ARPKD by second trimester ultrasound have to be considered when counselling a couple at risk for this particular disorder