674 research outputs found
Modelling clumpy PDRs in 3D - Understanding the Orion Bar stratification
Context. Models of photon-dominated regions (PDRs) still fail to fully
reproduce some of the observed properties, in particular the combination of the
intensities of different PDR cooling lines together with the chemical
stratification, as observed e.g. for the Orion Bar PDR. Aims. We aim to
construct a numerical PDR model, KOSMA-\tau 3D, to simulate full spectral cubes
of line emission from arbitrary PDRs in three dimensions (3D). The model is to
reproduce the intensity of the main cooling lines from the Orion Bar PDR and
the observed layered structure of the different transitions. Methods. We build
up a 3D compound, made of voxels ("3D pixels") that contain a discrete mass
distribution of spherical "clumpy" structures, approximating the fractal ISM.
To analyse each individual clump the new code is combined with the KOSMA-\tau
PDR model. Probabilistic algorithms are used to calculate the local FUV flux
for each voxel as well as the voxel-averaged line emissivities and optical
depths, based on the properties of the individual clumps. Finally, the
computation of the radiative transfer through the compound provides full
spectral cubes. To test the new model we try to simulate the structure of the
Orion Bar PDR and compare the results to observations from HIFI/Herschel and
from the Caltech Submillimetre Observatory (CSO). In this context new Herschel
data from the HEXOS guaranteed-time key program is presented. Results. Our
model is able to reproduce the line integrated intensities within a factor 2.5
and the observed stratification pattern within 0.016 pc for the [Cii] 158 \mu m
and different 12/13 CO and HCO+ transitions, based on the representation of the
Orion Bar PDR by a clumpy edge-on cavity wall. In the cavity wall, a large
fraction of the total mass needs to be contained in clumps. The mass of the
interclump medium is constrained by the FUV penetration. Furthermore, ...Comment: Major changes compared to v1. Also several references have been adde
Pengaruh Kemampuan Dan Motivasi Terhadap Kinerja Karyawan
The main fokus of this research was to find out the effect of motivation and ability on employee\u27s performance at PNPM Mandiri Perdesaan Office of Central Java Province. The respondents in this study were all employees there were 25 employees. Statistic analysis that used to test the hypothesis was multiple linier regression, and to be counted with SPSS for Window program. Due to the study, it was found that there were significant positif effects of ability and motivation on employee\u27s performance at PNPM Mandiri Perdesaan Office of Central Java Province. So it is important to improve ability and motivation in order to improve employee\u27s performance
(M-theory-)Killing spinors on symmetric spaces
We show how the theory of invariant principal bundle connections for
reductive homogeneous spaces can be applied to determine the holonomy of
generalised Killing spinor covariant derivatives of the form in a purely algebraic and algorithmic way, where is a left-invariant homomorphism. Specialising this
to the case of symmetric M-theory backgrounds (i.e. with a
symmetric space and an invariant closed 4-form), we derive several criteria
for such a background to preserve some supersymmetry and consequently find all
supersymmetric symmetric M-theory backgrounds.Comment: Updated abstract for clarity. Added missing geometries to section 6.
Main result stand
Pengaruh Berat Molekul Kitosan terhadap Sifat Fisis Kertas Daur Ulang
Pada penelitian ini, dilakukan proses pembuatan kertas dari
campuran kertas daur ulang dan serat jerami padi yang telah mengalami proses
penghilangan lignin, dengan rasio perbandingan 9:1. Biopolimer kitosan ditambahkan ke
dalam formulasi untuk meningkatkan mutu kertas daur ulang yang ditinjau dari sifat
fisisnya. Untuk mendapatkan kitosan dengan berbagai berat molekul (Mv = 3,52.105-
2,55.10) dilakukan proses hidrolisis kimia dengan larutan HCl pada berbagai variasi
konsentrasi dan waktu hidrolisis. Tujuan dari penelitian ini adalah untuk mempelajari
pengaruh berat molekul dan konsentrasi kitosan yang ditambahkan terhadap sifat fisis
kertas ditinjau dari kekuatan tarik dan daya serap terhadap air. Hasil penelitian
menunjukkan bahwa kitosan dengan berat molekul rendah dapat meningkatkan kekuatan
tarik dan menurunkan daya serap air kertas daur ulang. Kekuatan tarik maksimum dan
daya serap air minimum dicapai dengan penambahan kitosan pada berat molekul (Mv =
4,95.10) dan konsentrasi 8% bera
Studi Kasus Pekerjaan Produksi Dan Pemasangan Dinding Precast Pada Proyek Apartemen
Kesuksesan suatu proyek konstruksi dipengaruhi oleh beberapa faktor. Salah satunya adalah manajemen sumber daya, baik material maupun tenaga kerja. Hal ini dapat ditinjau dari besarnya produktivitas masing - masing pekerjaan.Penelitian ini bertujuan untuk mengukur besarnya produktivitas pekerjaan dinding precast pada 2 tower yang berbeda dalam proses produksi maupun pemasangan. Metode yang digunakan untuk mengukur produktivitas adalah pengamatan langsung di lapangan. Dari data tersebut lalu dilakukan analisis dengan metode Level of Effort sehingga dapat diketahui nilai produktivitas harian (daily productivity) pada masing - masing pekerjaan.Hasil perhitungan menunjukkan bahwa pada tower X, daily productivity pekerjaan produksi sebesar 3,529 m2/manday sedangkan pemasangan sebesar 3,631 buah /manday. Pada tower Y untuk pekerjaan produksi sebesar 3,485 m2/manday dan pekerjaan pemasangan sebesar 6,605 buah/manda
RNA interference knockdown of BRASSINOSTEROID INSENSITIVE1 in maize reveals novel functions for brassinosteroid signaling in controlling plant architecture
Brassinosteroids (BRs) are plant hormones involved in various growth and developmental processes. The BR signaling system is well established in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) but poorly understood in maize (Zea mays). BRASSINOSTEROID INSENSITIVE1 (BRI1) is a BR receptor, and database searches and additional genomic sequencing identified five maize homologs including duplicate copies of BRI1 itself. RNA interference (RNAi) using the extracellular coding region of a maize zmbril complementary DNA knocked down the expression of all five homologs. Decreased response to exogenously applied brassinolide and altered BR marker gene expression demonstrate that zmbriI-RNAi transgenic lines have compromised BR signaling. zmbriI-RNAi plants showed dwarf stature due to shortened internodes, with upper internodes most strongly affected. Leaves of zmbriI-RNAi plants are dark green, upright, and twisted, with decreased auricle formation. Kinematic analysis showed that decreased cell division and cell elongation both contributed to the shortened leaves. A BRASSINOSTEROID INSENSITIVE1-ETHYL METHANESULFONATE-SUPPRESSOR1-yellow fluorescent protein (BES1-YFP) transgenic line was developed that showed BR-inducible BES1-YFP accumulation in the nucleus, which was decreased in zmbriI-RNAi. Expression of the BES1-YFP reporter was strong in the auricle region of developing leaves, suggesting that localized BR signaling is involved in promoting auricle development, consistent with the zmbriI-RNAi phenotype. The blade-sheath boundary disruption, shorter ligule, and disrupted auricle morphology of RNAi lines resemble KNOTTED1-LIKE HOMEOBOX (KNOX) mutants, consistent with a mechanistic connection between KNOX genes and BR signaling
Hubungan Metilasi DNA dengan Ekspresi Gen MADS-box pada Buah Mantel Tanaman Kelapa Sawit (Elaeis Guineensis Jacq.)
The presence of mantled fruit on large-scale clonal production of oil palm had trully decreased the oil productivity. Mantled phenotype is likely to be that of an epigenetic change involving DNA methylation and the MADS-box transcription factor gene which encoded floral organ homeotic transformation. The objectives of this research were to quantify the degree of methylation which determined fruit abnormality through Ultra Performance Liquid Chromatography (UPLC) and to study its correlation with the MADS-box EgAGL6, EgAG2, and EgAGA genes expressed on mantled fruit derived from oil palm clonal plants which have been quantified using Quantitative Real-Time PCR (qPCR). This research was arranged in two replications for each gene and cDNA. The expression of the target genes were compared to EF1-α1 as the reference gene. Through the Least Significant Difference (LSD) Test at 95% confidence level of qPCR result, EgAGL6 expression was significantly lower in mantled fruit which decreased from 1.88 fold in Abn m to 0.46 fold in Abn. EgAG2 expression was increased non-significantly from 0.91 fold in Abn m to 1.13 fold in Abn, while EgAGA expression was higher in mantled which increased significantly from 1.48 fold in Abn m to 1.71 fold in Abn. Nuclease S1 digestion and UPLC revealed the genome-wide increase in DNA methylation on mantled fruit (18.33-19.55%) compared to its normal counterparts (5.67%). This increased in global DNA methylation was showed by the significant decreased in EgAGL6 transcript level of mantled fruit. This gene assumed to be involved in the development of mantled fruit
Relationships among Members of the Genus Myxobolus (Myxozoa: Bilvalvidae) Based on Small Subunit Ribosomal DNA Sequences
Sequences representing similar to 1,700 base pairs of the 18S rRNA gene from 10 different species in the genus Myxobulus were found to group them into 3 clusters that showed little correlation with spore morphology and size or host specificity, criteria currently used for both higher and lower taxonomic placements in the Myxozoa. Of the phenotypic criteria examined, tissue tropism was most correlated with the rRNA groupings observed. Spores of similar size and shape (Myxobolus cerebralis vs. Myxobolus squamalis) were distantly related in some instances, whereas spores with divergent morphology and size were some times found to be closely related (M. cerebralis and Myxobolus insidiosus). These initial investigations into the phylogenetic relationships of putative members of the genus Myxobolus clearly indicate the potential limitations of groupings based on size and morphological properties of the spores and host species infected. We propose that 18S rRNA gene sequences, combined with information on tissue tropism, host species infected, and developmental cycles in the fish and alternate host (when and if known) be given greater consideration in taxonomic placements of myxosporeans
Standard methods for Apis mellifera anatomy and dissection
An understanding of the anatomy and functions of internal and external structures is fundamental to many studies on the honey bee Apis mellifera. Similarly, proficiency in dissection techniques is vital for many more complex procedures. In this paper, which is a prelude to the other papers of the COLOSS BEEBOOK, we outline basic honey bee anatomy and basic dissection techniques
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