A Faster Triphosphorylation Ribozyme.

In support of the RNA world hypothesis, previous studies identified trimetaphosphate (Tmp) as a plausible energy source for RNA world organisms. In one of these studies, catalytic RNAs (ribozymes) that catalyze the triphosphorylation of RNA 5'-hydroxyl groups using Tmp were obtained by in vitro selection. One ribozyme (TPR1) was analyzed in more detail. TPR1 catalyzes the triphosphorylation reaction to a rate of 0.013 min-1 under selection conditions (50 mM Tmp, 100 mM MgCl2, 22°C). To identify a triphosphorylation ribozyme that catalyzes faster triphosphorylation, and possibly learn about its secondary structure TPR1 was subjected to a doped selection. The resulting ribozyme, TPR1e, contains seven mutations relative to TPR1, displays a previously unidentified duplex that constrains the ribozyme's structure, and reacts at a 24-fold faster rate than the parent ribozyme. Under optimal conditions (150 mM Tmp, 650 mM MgCl2, 40°C), the triphosphorylation rate of TRP1e reaches 6.8 min-1

Photoluminescence-based measurements of the energy gap and diffusion length of Zn_3P_2

The steady-state photoluminescence spectra of zinc phosphide (Zn_3P_2) wafers have revealed a fundamental indirect band gap at 1.38 eV, in close proximity to the direct band gap at 1.50 eV. These values are consistent with the values for the indirect and direct band gaps obtained from analysis of the complex dielectric function deduced from spectroscopic ellipsometric measurements. Bulk minority carrier lifetimes of 20 ns were observed by time-resolved photoluminescence decay measurements, implying minority-carrier diffusion lengths of ≥ 7 µm

Precise B, B_s and B_c meson spectroscopy from full lattice QCD

We give the first accurate results for $B$ and $B_s$ meson masses from lattice QCD including the effect of $u$, $d$ and $s$ sea quarks, and we improve an earlier value for the $B_c$ meson mass. By using the Highly Improved Staggered Quark action for $u/d$, $s$ and $c$ quarks and NRQCD for the $b$ quarks, we are able to achieve an accuracy in the masses of around 10 MeV. Our results are: $m_B$ = 5.291(18) GeV, $m_{B_s}$ = 5.363(11) GeV and $m_{B_c}$ = 6.280(10) GeV. Note that all QCD parameters here are tuned from other calculations, so these are parameter free tests of QCD against experiment. We also give scalar, $B_{s0}^*$, and axial vector, $B_{s1}$, meson masses. We find these to be slightly below threshold for decay to $BK$ and $B^*K$ respectively.Comment: 22 pages, 19 figure

Three Flavor QCD at High Temperatures

We have continued our study of the phase diagram of high temperature QCD with three flavors of improved staggered quarks. We are performing simulations with three degenerate quarks with masses less than or equal to the strange quark mass m_s and with degenerate up and down quarks with masses m_{u,d} less than the strange quark mass. For the quark masses studied to date, we find a crossover that strengthens as m_{u,d} decreases, rather than a bona fide phase transition. We present new results for the crossover temperature extrapolated to the physical value of m_{u,d}, and for quark number susceptibilities.Comment: Poster presented at Lattice 2004 (non-zero), Fermilab, June 21-26, 2004, 3 pages, 3 figure

Analisis Unit Cost Pelayanan Rawat Inap Postpartum Di Rumah Sakit Umum Dewi Sartika Dengan Menggunakan Metode Activity Based Costing (ABC) System

Iklim kompetitif tidak hanya terjadi pada Perusahaan yang berorientasi profit, namun juga berdampak padaperusahaan yang berorientasi nonprofit, salah satunya adalah rumah sakit. Rumah sakit yang berada di SulawesiTenggara pada tahun 2014 berjumlah 36, sedangkan kota Kendari memiliki 13 rumah sakit dan harus melayani347.496 penduduk. Hal ini menjadikan persaingan bisnis rumah sakit baik umum maupun swasta kini semakinketat. Salah satu solusi untuk memenangkan persaingan adalah dengan cara menentukan tarif yang lebih rendahdan kualitas atau jasa yang lebih tinggi dari pada pesaing. Solusi tersebut tentunya menjadikan biaya operasionalrumah sakit akan semakin besar sehingga sistem akuntansi manajemen di rumah sakit harus efektif dan efisiensehingga menghasilkan informasi yang akurat dalam pengambilan keputusan. Rumah sakit cenderung masihmenggunakan system akuntansi tradisional yang memiliki distorsi biaya. Penelitian ini menganalisis perhitungantarif rawat inap pelayanan postpartum di RSU Dewi Sartika menggunakan metode activity based costing system.Penelitian ini menggunakan metode deskriptif komparatif dengan pendekatan kuantitatif, data yang digunakanadalah seluruh data keuangan pada Oktober 2015-September 2016 dan aktivitas yang diobservasi yaitu ruangperawatan kelas VIP, kelas I, kelas II, kelas III dan bangsal. Hasil perhitungan menunjukkan hasil yang berbeda daritarif yang diterapkan. Tarif kelas VIP, kelas I dan kelas III lebih rendah dari tarif rumah sakit sedangkan tarif kelas IIdan bangsal lebih tinggi

Mining for nonribosomal peptide synthetase and polyketide synthase genes revealed a high level of diversity in the sphagnum bog metagenome

Sphagnum bog ecosystems are one of the oldest vegetation forms harbouring a specific microbial community, which is known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome indicate a rich secondary metabolism, the genes are not yet explored. To analyse non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) the diversity of NRPS and PKS genes in Sphagnum-associated metagenome was investigated by in silico data mining and sequence-based screening (PCR-amplification of 9500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPS, 346 PKS, as well as 40 PKS-NRPS hybrid gene sequences. Occurrence of NRPS sequences was strongly dominated by the phyla Protebacteria, especially by the genus Burkholderia, while PKS sequences were mainly affiliated to Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR-amplification screening, displaying amino acid sequence identities of 48 to 91% to annotated sequences of the phyla Proteobacteria, Actinobacteria and Cyanobacteria. Some of the identified metagenomic clones showed closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of yet undescribed bioactive metabolites. This study highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications

Middle Miocene Tectonic Boundary Conditions for Use in Climate Models

Utilizing general circulation models (GCMs) for paleoclimate study requires the construction of appropriate model boundary conditions. We present a middle Miocene paleotopographic and paleobathymetric reconstruction geographically constrained at 15 Ma for use in GCMs. Paleotopography and paleogeography are reconstructed using a published global plate rotation model and published geological data. Paleobathymetry is reconstructed through application of an age-depth relationship to a middle Miocene global digital isochron map, followed by the overlay of reconstructed sediment thickness and large igneous provinces. Adjustments are subsequently made to ensure our reconstruction may be utilized in GCMs

The formation of voids in a universe with cold dark matter and a cosmological constant

A spherical Lagrangian hydrodynamical code has been written to study the formation of cosmological structures in the early Universe. In this code we take into account the presence of collisionless non-baryonic cold dark matter (CDM), the cosmological constant and a series of physical processes present during and after the recombination era, such as photon drag resulting from the cosmic background radiation and hydrogen molecular production. We follow the evolution of the structure since the recombination era until the present epoch. As an application of this code we study the formation of voids starting from negative density perturbations which evolved during and after the recombination era. We analyse a set of COBE-normalized models, using different spectra to see their influence on the formation of voids. Our results show that large voids with diameters ranging from 10h^{-1} Mpc up to 50h^{-1} Mpc can be formed in a universe model dominated by the cosmological constant (\Omega_\Lambda ~ 0.8). This particular scenario is capable of forming large and deep empty regions (with density contrasts \delta < -0.6). Our results also show that the physical processes acting on the baryonic matter produce a transition region where the radius of the dark matter component is greater than the baryonic void radius. The thickness of this transition region ranges from about tens of kiloparsecs up to a few megaparsecs, depending on the spectrum considered. Putative objects formed near voids and within the transition region would have a different amount of baryonic/dark matter when compared with \Omega_b/\Omega_d. If one were to use these galaxies to determine, by dynamical effects or other techniques, the quantity of dark matter present in the Universe, the result obtained would be only local and not representative of the Universe as a whole.Comment: MNRAS (in press); 9 pages, no figure

Passivation of Zn_3P_2 substrates by aqueous chemical etching and air oxidation

Surface recombination velocities measured by time-resolved photoluminescence and compositions of Zn_(3)P_2 surfaces measured by x-ray photoelectron spectroscopy (XPS) have been correlated for a series of wet chemical etches of Zn_(3)P_2 substrates. Zn_(3)P_2 substrates that were etched with Br_2 in methanol exhibited surface recombination velocity values of 2.8 × 10^4 cm s^(−1), whereas substrates that were further treated by aqueous HF–H_(2)O_2 exhibited surface recombination velocity values of 1.0 × 10^4 cm s^(−1). Zn_(3)P_2 substrates that were etched with Br_2 in methanol and exposed to air for 1 week exhibited surface recombination velocity values of 1.8 × 10^3 cm s^(−1), as well as improved ideality in metal/insulator/semiconductor devices

Cosmic-Ray Positrons: Are There Primary Sources?

Cosmic rays at the Earth include a secondary component originating in collisions of primary particles with the diffuse interstellar gas. The secondary cosmic rays are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.Comment: 15 pages, Latex, epsfig and aasms4 macros required, to appear in Astroparticle Physics (1999