375 research outputs found
Genesis of Augite-Bearing Ureilites: Evidence From LA-ICP-MS Analyses of Pyroxenes and Olivine
Ureilites are ultramafic achondrites composed primarily of coarse-grained low-Ca pyroxene and olivine with interstitial carbonaceous material, but a number of them contain augite [1]. Ureilites are considered to be restites after partial melting of a chondritic precursor, although at least some augite-bearing ureilites may be partially cumulate [1, 2]. In this scenario, the augite is a cumulus phase derived from a melt that infiltrated a restite composed of typical ureilite material (olivine+low-Ca pyroxene) [2]. To test this hypothesis, we examined the major and trace element compositions of silicate minerals in select augite-bearing ureilites with differing mg#. Polished thick sections of the augite-bearing ureilites ALH 84136 , EET 87511, EET 96293, LEW 88201, and META78008 and augite-free typical ureilite EET 90019 were examined by EPMA for major and minor elements and laser ablation ICP-MS (LA-ICP-MS) for trace elements, REE in particular. Although EET 87511 is reported to contain augite, the polished section that we obtained did not
An Evaluation of the Philippine Population Management Program (PPMP)
Early child-bearing and high fertility still persist especially among the poor, despite the more than two decades of family planning program implementation in the Philippines. Using an evaluation framework that links inputs, outputs, utilization of outputs and outcomes, the paper analyzes the impact of the different components of the Philippine Population Management Program (PPMP), namely: family planning and responsible parenthood, reproductive health, adolescent health and youth development, and integration of population and development. On the inputs and output side, the paper utilizes the expenditures on the different components of the program for the years 1998 and 2000 presented in Racelis and Herrin (2003). Data from the several rounds of the national demographic survey, family planning survey and maternal and child health survey were used to generate utilization and outcomes indicators. The paper highlights the inadequate institutional and financial support as the primary cause of the population programs ineffectual performance
Improving Local Data to Deliver High Quality Maternal and Child Health and Family Planning Services to the Poor in the Philippines
Locally-generated data facilitates strategic provision of high level family planning (FP) and maternal and child health (MCH) services to its constituents. However, generation of such data remains to be a complex undertaking at the local level owing to both financial and technical capacity constraints. The USAIDassisted HealthGov Project, in collaboration with its regional and local counterparts, has facilitated innovations to improve existing information on health program coverage and identification of unmet need for FP and MCH and to generate new information on logistics and service delivery capacity of the supply side. Such innovations motivate the use of information not only in planning but real-time provision of FP and MCH services. The Department of Health (DOH) continues its efforts and technical assistance to sustain such innovations so that generation and analysis of data becomes an inherent part of the provision of services at the local level
Almahata Sitta and Brecciated Ureilites: Insights into the Heterogeneity of Asteroids and Implications for Sample Return
Analysis of samples returned to terrestrial laboratories enables more precise measurements and a wider range of techniques to be utilized than can be achieved with either remote sensing or rover instruments. Furthermore, returning samples to Earth allows them to be stored and re-examined with future technology. Following the success of the Hayabusa mission, returning samples from asteroids should be a high priority for understanding of early solar system evolution, planetary formation and differentiation. Meteorite falls provide us with materials and insight into asteroidal compositions. Almahata Sitta (AS) was the first meteorite fall from a tracked asteroid (2008 TC3) [1] providing a rare opportunity to compare direct geochemical observations with remote sensing data. Although AS is predominantly ureilitic, multiple chondritic fragments have been associated with this fall [2,3]. This is not unique, with chondritic fragments being found in many howardite samples (as described in a companion abstract [4]) and in brecciated ureilites, some of which are known to represent ureilitic regolith [5-7]. The heterogeneity of ureilite samples, which are thought to all originate from a single asteroidal ureilite parent body (UPB) [5], gives us information about both internal and external asteroidal variations. This has implications both for the planning of potential sample return missions and the interpretation of material returned to Earth. This abstract focuses on multiple fragments of two meteorites: Almahata Sitta (AS); and Dar al Gani (DaG) 1047 (a highly brecciated ureilite, likely representative of ureilite asteroidal regolith)
Oxygen Isotope Systematics of Almahata Sitta
The Almahata Sitta (hereafter "AHS") meteorite was derived from an impact of asteroid 2008TC3 on Earth and is classified as an anomalous polymict ureilite. More than 600 meteorite fragments have been recovered from the strewnfield. Previous reports indicate that these fragments consist mainly of ureilitic materials with textures and compositions, while some fragments are found to be chondrites of a wide range of chemical classes. Bulk oxygen three isotope analyses of ureilitic fragments from AHS fall close to the CCAM (Carbonaceous Chondrite Anhydrous Mineral) line similar to ureilites. In order to further compare AHS with known ureilites, we performed high precision SIMS (Secondary Ion Mass Spectrometer) oxygen isotope analyses of some AHS sample
Experimental and Mathematical Techniques for Kinetic Studies of Larval Fruit Fly Growth
Techniques have been developed in our laboratory which permit the study of growth patterns under a variety of experimental conditions. The experimental subject under investigation is the larva of the common fruit fly Drosophilia melanogaster. Studies involving exposure of the organism to thermal, gravitational, electromagnetic, and magnetic agents have already been conducted. A particular advantage of employing the larvae is that they possess a relatively rapid and simple growth pattern from which experimental constants can be obtained and statistically analyzed. During their 96-hour growth period, the approximate time from the hatching of the egg to pupae formation, the larvae need only be interrupted for about one-half hour each day for purposes of measurement. Growth patterns have been fitted to curves predicted by Compound-Interest and Verhulst-Reed-Pearl Equations. During the early growth phase excellent fit can be obtained to the exponential curve predicted by the former equation
Globular-shaped variable lymphocyte receptors B antibody multimerized by a hydrophobic clustering in hagfish
In hagfish and lampreys, two representative jawless vertebrates, the humoral immunity is directly mediated by variable lymphocyte receptors B (VLRBs). Both monomeric VLRBs are structurally and functionally similar, but their C-terminal tails differ: lamprey VLRB has a Cys-rich tail that forms disulfide-linked pentamers of dimers, contributing to its multivalency, whereas hagfish VLRB has a superhydrophobic tail of unknown structure. Here, we reveal that VLRBs obtained from hagfish plasma have a globular-shaped multimerized form (approximately 0.6 to 1.7 MDa) that is generated by hydrophobic clustering instead of covalent linkage. Electron microscopy (EM) and single-particle analysis showed that the multimerized VLRBs form globular-shaped clusters with an average diameter of 28.7 ± 2.2 nm. The presence of VLRBs in the complex was confirmed by immune-EM analysis using an anti-VLRB antibody. Furthermore, the hydrophobic hagfish C-terminus (HC) was capable of triggering multimerization and directing the cellular surface localization via a glycophosphatidylinositol linkage. Our results strongly suggest that the hagfish VLRB forms a previously unknown globular-shaped antibody. This novel identification of a structurally unusual VLRB complex may suggest that the adaptive immune system of hagfish differs from that of lamprey
Seismic Search for Strange Quark Nuggets
Bounds on masses and abundances of Strange Quark Nuggets (SQNs) are inferred
from a seismic search on Earth. Potential SQN bounds from a possible seismic
search on the Moon are reviewed and compared with Earth capabilities. Bounds
are derived from the data taken by seismometers implanted on the Moon by the
Apollo astronauts. We show that the Apollo data implies that the abundance of
SQNs in the region of 10 kg to one ton must be at least an order of magnitude
less than would saturate the dark matter in the solar neighborhood.Comment: 7 pages and 4 tables, plus 3 attached figures. Revised version
responds to helpful comments of Phys. Rev. referee by adding 3 figures,
subtracting two tables and taking into account information from QC
Structure, circadian regulation and bioinformatic analysis of the unique sigma factor gene in Chlamydomonas reinhardtii
Abstract In higher plants, the transcription of plastid genes is mediated by at least two types of RNA polymerase (RNAP); a plastid-encoded bacterial RNAP in which promoter specificity is conferred by nuclear-encoded sigma factors, and a nuclear-encoded phage-like RNAP. Green algae, however, appear to possess only the bacterial enzyme. Since transcription of much, if not most, of the chloroplast genome in Chlamydomonas reinhardtii is regulated by the circadian clock and the nucleus, we sought to identify sigma factor genes that might be responsible for this regulation. We describe a nuclear gene (RPOD) that is predicted to encode an 80 kDa protein that, in addition to a predicted chloroplast transit peptide at the N-terminus, has the conserved motifs (2.1-4.2) diagnostic of bacterial sigma-70 factors. We also identified two motifs not previously recognized for sigma factors, adjacent PEST sequences and a leucine zipper, both suggested to be involved in protein-protein interactions. PEST sequences were also found in 40% of sigma factors examined, indicating they may be of general significance. Southern blot hybridization and BLAST searches of the genome and EST databases suggest that RPOD may be the only sigma factor gene in C. reinhardtii. The levels of RPOD mRNA increased 2-3-fold in the mid-to-late dark period of light-dark cycling cells, just prior to, or coincident with, the peak in chloroplast transcription. Also, the dark-period peak in RPOD mRNA persisted in cells shifted to continuous light or continuous dark for at least one cycle, indicating that RPOD is under circadian clock control. These results suggest that regulation of RPOD expression contributes to the circadian clock's control of chloroplast transcription
- …