Unexplained Sets of Seismographic Station Reports and A Set Consistent with a Quark Nugget Passage

In 1984 Edward Witten proposed that an extremely dense form of matter composed of up, down, and strange quarks may be stable at zero pressure (Witten, 1984). Massive nuggets of such dense matter, if they exist, may pass through the Earth and be detectable by the seismic signals they generate (de Rujula and Glashow, 1984). With this motivation we investigated over 1 million seismic data reports to the U.S. Geological Survey for the years 1990-1993 not associated with epicentral sources. We report two results: (1) with an average of about 0.16 unassociated reports per minute after data cuts, we found a significant excess over statistical expectation for sets with ten or more reports in ten minutes; and (2) in spite of a very small a priori probability from random reports, we found one set of reports with arrival times and other features appropriate to signals from an epilinear source. This event has the properties predicted for the passage of a nugget of strange quark matter (SQM) through the earth, although there is no direct confirmation from other phenomenologies.Comment: 23 pages, 9 figures, one previously described event eliminated, extensive examination of the second event as a possible association of random reports, additional analysis of the data set, search algorithms, and waveform

Evaluation of Short-Period, Near-Regional M_s Scales for the Nevada Test Site

Surface wave magnitude (M_s) estimation for small events recorded at near-regional distances will often require a magnitude scale designed for Rayleigh waves with periods less than 10 sec. We have examined the performance of applying two previously published M_s scales on 7-sec Rayleigh waves recorded at distances less than 500 km. First, we modified the Marshall and Basham (1972) M_s scale, originally defined for periods greater than 10 sec, to estimate surface wave magnitudes for short-period Rayleigh waves from earthquakes and explosions on or near the Nevada Test Site. We refer to this modification as ^(M+B) M_s(7), and we have used short-period, high-quality dispersion curves to determine empirical path corrections for the 7-sec Rayleigh waves. We have also examined the performance of the Rezapour and Pearce (1998) formula, developed using theoretical distance corrections and surface wave observations with periods greater than 10 sec, for 7-sec Rayleigh waves ^(R+P) (M_S(7)) as recorded from the same dataset. The results demonstrate that both formulas can be used to estimate M_s for nuclear explosions and earthquakes over a wider magnitude distribution than is possible using conventional techniques developed for 20-sec Rayleigh waves. These M_s(7) values scale consistently with other Ms studies at regional and teleseismic distances with the variance described by a constant offset; however, the offset for the ^(M+B) M_s(7) estimates is over one magnitude unit nearer the teleseismic values than the ^(R+P) M_s(7) estimates. Using our technique, it is possible to employ a near-regional single-station or sparse network to estimate surface wave magnitudes, thus allowing quantification of the size of both small earthquakes and explosions. Finally, we used a jackknife technique to determine the false-alarm rates for the ^(M+B) M_s(7)-m_b discriminant for this region and found that the probability of misclassifying an earthquake as an explosion is 10%, while the probability of classifying an explosion as an earthquake was determined to be 1.2%. The misclassification probabilities are slightly higher for the ^(R+P) M_s(7) estimates. Our future research will be aimed at examining the transportability of these methods

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

Millimeter-wave Signature of Strange Matter Stars

One of the most important questions in the study of compact objects is the nature of pulsars, including whether they consist of neutron matter or strange quark matter (SQM). However, few mechanisms for distinguishing between these two possibilities have been proposed. The purpose of this paper is to show that a strange star (one made of SQM) will have a vibratory mode with an oscillation frequency of approximately 250 GHz (millimeter wave). This mode corresponds to motion of the center of the expected crust of normal matter relative to the center of the strange quark core, without distortion of either. Radiation from currents generated in the crust at the mode frequency would be a SQM signature. We also consider effects of stellar rotation, estimate power emission and signal-to-noise ratio, and discuss briefly possible mechanisms for exciting the mode.Comment: 13 pages, Latex, one figur

Biochemical and mutagenic analysis of I-CreII reveals distinct but important roles for both the H-N-H and GIY-YIG motifs

Homing endonucleases typically contain one of four conserved catalytic motifs, and other elements that confer tight DNA binding. I-CreII, which catalyzes homing of the Cr.psbA4 intron, is unusual in containing two potential catalytic motifs, H-N-H and GIY-YIG. Previously, we showed that cleavage by I-CreII leaves ends (2-nt 3′ overhangs) that are characteristic of GIY-YIG endonucleases, yet it has a relaxed metal requirement like H-N-H enzymes. Here we show that I-CreII can bind DNA without an added metal ion, and that it binds as a monomer, akin to GIY-YIG enzymes. Moreover, cleavage of supercoiled DNA, and estimates of strand-specific cleavage rates, suggest that I-CreII uses a sequential cleavage mechanism. Alanine substitution of a number of residues in the GIY-YIG motif, however, did not block cleavage activity, although DNA binding was substantially reduced in several variants. Substitution of conserved histidines in the H-N-H motif resulted in variants that did not promote DNA cleavage, but retained high-affinity DNA binding—thus identifying it as the catalytic motif. Unlike the non-specific H-N-H colicins, however; substitution of the conserved asparagine substantially reduced DNA binding (though not the ability to promote cleavage). These results indicate that, in I-CreII, two catalytic motifs have evolved to play important roles in specific DNA binding. The data also indicate that only the H-N-H motif has retained catalytic ability

Pooling job physical exposure data from multiple independent studies in a consortium study of carpal tunnel syndrome

Pooling data from different epidemiological studies of musculoskeletal disorders (MSDs) is necessary to improve statistical power and to more precisely quantify exposure–response relationships for MSDs. The pooling process is difficult and time-consuming, and small methodological differences could lead to different exposure–response relationships. A subcommittee of a six-study research consortium studying carpal tunnel syndrome: (i) visited each study site, (ii) documented methods used to collect physical exposure data and (iii) determined compatibility of exposure variables across studies. Certain measures of force, frequency of exertion and duty cycle were collected by all studies and were largely compatible. A portion of studies had detailed data to investigate simultaneous combinations of force, frequency and duration of exertions. Limited compatibility was found for hand/wrist posture. Only two studies could calculate compatible Strain Index scores, but Threshold Limit Value for Hand Activity Level could be determined for all studies. Challenges of pooling data, resources required and recommendations for future researchers are discussed

Phylogenomic analysis of the Chlamydomonas genome unmasks proteins potentially involved in photosynthetic function and regulation

Chlamydomonas reinhardtii, a unicellular green alga, has been exploited as a reference organism for identifying proteins and activities associated with the photosynthetic apparatus and the functioning of chloroplasts. Recently, the full genome sequence of Chlamydomonas was generated and a set of gene models, representing all genes on the genome, was developed. Using these gene models, and gene models developed for the genomes of other organisms, a phylogenomic, comparative analysis was performed to identify proteins encoded on the Chlamydomonas genome which were likely involved in chloroplast functions (or specifically associated with the green algal lineage); this set of proteins has been designated the GreenCut. Further analyses of those GreenCut proteins with uncharacterized functions and the generation of mutant strains aberrant for these proteins are beginning to unmask new layers of functionality/regulation that are integrated into the workings of the photosynthetic apparatus

Final Technical Report

This report summarizes many of the projects, and lists all of the publications and persons trained with support from the grant