Exploring the Cosmic Evolution of Habitability with Galaxy Merger Trees

We combine inferred galaxy properties from a semi-analytic galaxy evolution model incorporating dark matter halo merger trees with new estimates of supernova and gamma ray burst rates as a function of metallicity from stellar population synthesis models incorporating binary interactions. We use these to explore the stellar mass fraction of galaxies irradiated by energetic astrophysical transients and its evolution over cosmic time, and thus the fraction which is potentially habitable by life like our own. We find that 18 per cent of the stellar mass in the Universe is likely to have been irradiated within the last 260 Myr, with GRBs dominating that fraction. We do not see a strong dependence of irradiated stellar mass fraction on stellar mass or richness of the galaxy environment. We consider a representative merger tree as a Local Group analogue, and find that there are galaxies at all masses which have retained a high habitable fraction (>40 per cent) over the last 6 Gyr, but also that there are galaxies at all masses where the merger history and associated star formation have rendered galaxies effectively uninhabitable. This illustrates the need to consider detailed merger trees when evaluating the cosmic evolution of habitability.Comment: 11 page, 10 figures. MNRAS accepted 13th Dec 2017. Updated to match accepted version, with additional discussion of metallicity effect

Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results

The Binary Population and Spectral Synthesis (BPASS) suite of binary stellar evolution models and synthetic stellar populations provides a framework for the physically motivated analysis of both the integrated light from distant stellar populations and the detailed properties of those nearby. We present a new version 2.1 data release of these models, detailing the methodology by which BPASS incorporates binary mass transfer and its effect on stellar evolution pathways, as well as the construction of simple stellar populations. We demonstrate key tests of the latest BPASS model suite demonstrating its ability to reproduce the colours and derived properties of resolved stellar populations, including well- constrained eclipsing binaries. We consider observational constraints on the ratio of massive star types and the distribution of stellar remnant masses. We describe the identification of supernova progenitors in our models, and demonstrate a good agreement to the properties of observed progenitors. We also test our models against photometric and spectroscopic observations of unresolved stellar populations, both in the local and distant Universe, finding that binary models provide a self-consistent explanation for observed galaxy properties across a broad redshift range. Finally, we carefully describe the limitations of our models, and areas where we expect to see significant improvement in future versions.Comment: 69 pages, 45 figures. Accepted for publication in PASA. Accompanied by a full, documented data release at http://bpass.auckland.ac.nz and http://warwick.ac.uk/bpas

Spectral diffusion and 14N quadrupole splittings in absorption detected magnetic resonance hole burning spectra of photosynthetic reaction centers

Zero field absorption detected magnetic resonance hole burning measurements were performed on photosynthetic reaction centers of the bacteria Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis. Extrapolation to zero microwave power yielded pseudohomogeneous linewidths of 2.0 MHz for Rhodopseudomonas viridis, 1.0 and 0.9 MHz for the protonated forms of Rhodobacter sphaeroides R26 with and without monomer bacteriochlorophyll exchanged, and 0.25 MHz as an upper limit for fully deuterated reaction centers of Rhodobacter sphaeroides R26. The measured linewidths were interpreted as being due to unresolved hyperfine interaction between the nuclear spins and the triplet electron spin, the line shape being determined by spectral diffusion among the nuclei. The difference in linewidths between Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis is then explained by triplet delocalization on the special pair in the former, and localization on one dimer half on the latter. In the fully deuterated sample, four quadrupole satellites were observed in the hole spectra arising from the eight 14N nitrogens in the special pair. The quadrupole parameters seem to be very similar for all nitrogens and were determined to =1.25±0.1 MHz and =0.9±0.1 MHz. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Lizards lack speed-accuracy trade-offs in a quantitative foraging task when unable to sample the reward.

To make decisions, animals gather information from the environment in order to avoid costs (e.g., reduced survival) and increase benefits (e.g., foraging success). When time is limited or information is insufficient, most animals face a speed-accuracy trade-off (SAT) - they have to balance the benefits of making quick decisions against the costs of inaccurate decisions. Here, we investigated the relationship between decision accuracy and decision speed in gidgee skinks (Egernia stokesii) performing a food-based spontaneous quantity discrimination task. Rather than a SAT we found a speed-accuracy alignment; lizards made decisions that were fast and accurate, rather than inaccurate. Furthermore, we found only within-, but no between-individual, differences in decision making indicating behavioural plasticity in the absence of individual decision styles. Finally, latency to choice was highly repeatable, more so than choice accuracy. Previous work has shown that learning, the costs of a bad decision and task difficulty frequently result in SATs. The lack of a SAT in our lizards might be a direct consequence of our simple testing methodology which prevented learning by not allowing lizards to consume the chosen quantity. To fully understand how SATs develop, different methodologies that control the costs and benefits of decisions should be compared

Prediksi Harga Saham PT. Bri, Tbk. Menggunakan Metode Arima (Autoregressive Integrated Moving Average)

PREDIKSI HARGA SAHAM PT. BRI, Tbk. MENGGUNAKAN METODE ARIMA (Autoregressive Integrated Moving Average) Greis S. Lilipaly1) , Djoni Hatidja1) , John S. Kekenusa1) ABSTRAK Metode ARIMA adalah salah satu metode yang dapat digunakan dalam memprediksi Perubahan harga saham. Tujuan dari penelitian ini adalah untuk membuat model ARIMA dan memprediksi harga saham PT. BRI, Tbk. bulan November 2014. Penelitian menggunakan data harga saham harian maksimum dan minimum PT. BRI, Tbk. Data yang digunakan yaitu data sekunder yang diambil dari website Perusahaan PT. BRI, Tbk. sejak 3 Januari 2011 sampai 20 Oktober 2014 untuk memprediksi harga saham bulan November 2014. Dari hasil penelitian menunjukkan bahwa data tahun 2011 sampai Oktober 2014 bisa digunakan untuk memprediksi harga saham bulan November 2014. Hasilnya model ARIMA untuk harga saham maksimum adalah ARIMA (2,1,3) dan harga saham minimum adalah model (2,1,3) yang dapat digunakan untuk memprediksi data bulan November 2014 dengan validasi prediksi yang diambil pada bulan Oktober 2014 untuk selanjutnya dilakukan prediksi bulan November 2014. Kata Kunci: Metode ARIMA, PT. BRI, Tbk., Saham THE PREDICTION STOCK PRICE OF PT. BRI, Tbk. USE ARIMA METHOD (Autoregressive Integrated Moving Average) ABSTRACT ARIMA method is one of the method that used to prediction the change of stock price. The purpose of this research is to make model of ARIMA and predict stock price of PT. BRI, Tbk. in November 2014. The research use maximum and minimum data of stock price daily of PT. BRI, Tbk. Data are used is secondary data that taking from website of PT. BRI, Tbk. since January 3rd 2011 until October 20th 2014 to predict stock price in November 2014. From this research show that data from 2011 until October 2014 can be used to predict the stock price in November 2014. The result of ARIMA\u27s model for the maximum stock price is ARIMA (2,1,3) and the minimum stock price is (2,1,3) can use to predict the data on November 2014 with predict validation that take on October 2014 and with that predict November 2014

Beban Kerja, Organizational Citizenship Behavior, dan Keterlibatan Kerja Pengaruhnya terhadap Kinerja Karyawan PT. Pln (Persero) Wilayah Suluttenggo Area Manado

Kesuksesan usaha dalam meningkatkan kualitas dan produktivitasnya melibatkan karyawan, karyawan menjadi penentu utama. Kinerja karyawan adalah kualitas dan kuantitas yang dicapai oleh seorang karyawan dalam melaksanakan tugasnya sesuai dengan tanggung jawab yang diberikan. Tujuan penelitian ini untuk mengetahui apakah Beban Kerja, Organizational Citizenship Behavior, dan Keterlibatan Kerja berpengaruh terhadap Kinerja Karyawan PT. PLN (Persero) Suluttenggo Area Manado dengan sampel sebanyak 51 karyawan tetap, menggunakan metode probability sampling khususnya proportionate stratified random sampling. Penelitian ini merupakan penelitian asosiatif dengan menggunakan analisis Regresi Berganda. Hasil penelitian menunjukan secara simultan Beban Kerja, Organizational Citizenship Behavior, dan Keterlibatan Kerja berpengaruh terhadap Kinerja Karyawan. Lebih lanjut, Beban Kerja tidak berpengaruh terhadap Kinerja Karyawan, namun Organizational Citizenship Behavior dan Keterlibatan Kerja berpengaruh positif terhadap Kinerja Karyawan. Sebaiknya para karyawan PT. PLN (Persero) Suluttenggo Area Manado lebih efisien dalam menyelesaikan Beban Kerja yang diterima dengan lebih fokus pada manajemen waktu sehingga tugas pekerjaan mereka dapat terselesaikan sesuai dengan waktu yang ditetapkan. Para karyawan juga diharapkan mempertahankan bahkan meningkatkan Organizational Citizenship Behavior dan Keterlibatan Kerja yang tinggi agar tercipta kinerja para karyawan menjadi lebih baik. Kata kunci: beban kerja, organizational citizenship behavior, keterlibatan kerja, kinerja karyawa

Pengaruh Kompetensi, Komitmen Organisasi dan Keterlibatan Kerja terhadap Kinerja Karyawan pada PT. Pln (Persero) Wilayah Suluttenggo

Karyawan sebagai sumber daya utama Perusahaan dituntut untuk memberikan pelayanan terbaik kepada konsumen dan memberikan kinerja yang optimal. Hal ini menunjukkan bahwa sumber daya manusia sangat berpengaruh terhadap kesuksesan Perusahaan dalam pencapaian tujuannya. Tujuan penelitian adalah untuk mengetahui apakah Kompetensi, Komitmen Organisasi dan Keterlibatan Kerja berpengaruh terhadap Kinerja Karyawan. Populasi Penelitian Merupakan Karyawan PT. PLN, dan sampel sebanyak 63 Karyawan. Metode penelitian yang digunakan adalah jenis penelitian asosiatif dengan teknik Analisa data menggunakan regresi linear berganda. Hasil penelitian menunjukan secara simultan Kompetensi, Keterlibatan Kerja berpengaruh terhadap Kinerja Karyawan, secara parsial Komitmen Organisasi tidak berpengaruh terhadap Kinerja Karyawan sedangkan Kompetensi dan Komitmen Organisasi berpengaruh positif dan signifikan terhadap Kinerja Karyawan. Pimpinan PT. PLN sebaiknya meningkatkan Kesejateraan karyawan, agar karyawan dapat merasa nyaman bekerja di Perusahaan. Kata kunci: kompetensi, komitmen, keterlibatan kerja, kinerj

Radio observations confirm young stellar populations in local analogues to z ~5 Lyman break galaxies

We present radio observations at 1.5 GHz of 32 local objects selected to reproduce the physical properties of z .5 star-forming galaxies. We also report non-detections of five such sources in the sub-millimetre. We find a radio-derived star formation rate which is typically half that derived from Hα emission for the same objects. These observations support previous indications that we are observing galaxies with a young dominant stellar population, which has not yet established a strong supernova-driven synchrotron continuum. We stress caution when applying star formation rate calibrations to stellar populations younger than 100 Myr. We calibrate the conversions for younger galaxies, which are dominated by a thermal radio emission component. We improve the size constraints for these sources, compared to previous unresolved ground-based optical observations. Their physical size limits indicate very high star formation rate surface densities, several orders of magnitude higher than the local galaxy population. In typical nearby galaxies, this would imply the presence of galaxy-wide winds. Given the young stellar populations, it is unclear whether a mechanism exists in our sources that can deposit sufficient kinetic energy into the interstellar medium to drive such outflows