Galactic cosmic rays on extrasolar Earth-like planets I. Cosmic ray flux

(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields, especially in the case of planets more massive than Earth (super-Earths). Planetary magnetic fields, however, constitute one of the shielding layers that protect the planet against cosmic-ray particles. In particular, a weak magnetic field results in a high flux of Galactic cosmic rays that extends to the top of the planetary atmosphere. We wish to quantify the flux of Galactic cosmic rays to an exoplanetary atmosphere as a function of the particle energy and of the planetary magnetic moment. We numerically analyzed the propagation of Galactic cosmic-ray particles through planetary magnetospheres. We evaluated the efficiency of magnetospheric shielding as a function of the particle energy (in the range 16 MeV $\le$ E $\le$ 524 GeV) and as a function of the planetary magnetic field strength (in the range 0 ${M}_\oplus$ $\le$ {M} $\le$ 10 ${M}_\oplus$). Combined with the flux outside the planetary magnetosphere, this gives the cosmic-ray energy spectrum at the top of the planetary atmosphere as a function of the planetary magnetic moment. We find that the particle flux to the planetary atmosphere can be increased by more than three orders of magnitude in the absence of a protecting magnetic field. For a weakly magnetized planet (${M}=0.05\,{M}_{\oplus}$), only particles with energies below 512 MeV are at least partially shielded. For a planet with a magnetic moment similar to Earth, this limit increases to 32 GeV, whereas for a strongly magnetized planet ($M=10.0\,{M}_{\oplus}$), partial shielding extends up to 200 GeV. We find that magnetic shielding strongly controls the number of cosmic-ray particles reaching the planetary atmosphere. The implications of this increased particle flux are discussed in a companion article.Comment: 10 pages, 9 figures; accepted in A&

UPAYA PENINGKATAN HASIL BELAJAR SISWA MELALUI PEMANFAATAN LINGKUNGAN BELAJAR PADA MATA PELAJARAN IPS KELAS VII DI SMP N 1 JALAKSANA KABUPATEN KUNINGAN

Atri Khodijah M. (58440944) : “Upaya Peningkatan Hasil Belajar Siswa Melalui Pemanfaatan Lingkungan Belajar Pada Mata Pelajaran IPS Kelas VII Di SMP N 1 Jalaksana Kabupaten Kuningan” Skripsi ini dilatar belakangi oleh temuan di lapangan dimana kondisi kelas VII Sekolah Menengah Pertama Negeri 1 Jalaksana memiliki karakteristik lingkungan belajar yang relatif sangat mendukung untuk proses belajar mengajar. Hal ini dikarenakan letak SMP Negeri 1 Jalaksana tidak jauh dari jalan Kabupaten, lokasi sekolahnya juga tidak begitu ramai dari pemukiman penduduk. Hasil belajar siswa di SMP Negeri 1 Jalaksana khususnya di kelas VII menunjukan hasil belajar yang relatif baik. Namun, dalam tata letak kelas tidak strategis, karena letak kelas VII sangat berdekatan dengan lapangan basket, kondisi di dalam kelas kurang mendukung seperti pengaturan tempat duduk, penempatan alat kebersihan yang kurang baik dan kurangnya kesadaran guru untuk memperhatikan kebersihan lingkungan sebelum memulai kegiatan belajar mengajar. Tujuan peneliti an ini adalah untuk memperoleh kejelasan data tentang (1) Pemanfaatan Lingkungan Belajar dalam proses belajar IPS kelas VII di SMP N 1 Jalaksana-Kuningan (2)Respon siswa kelas VII di SMP N 1 Jalaksana-Kuningan terhadap pembelajaran dengan menggunakan media lingkungan pada mata peajaran IPS (3) Hasil belajar siswa kelas VII pada mata pelajaran IPS di SMP N 1 Jalaksana-Kuningan dengan pemanfaatan lingkungan belajar. Lingkungan belajar merupakan suatu konteks fisik, sosial, dan psikologis yang dalam konteks tersebut anak belajar dan memperoleh perilaku baru. Pengakuan popular akan peran guru dalam memanfaatkan lingkungan belajar baik fisik maupun non fisik dalam proses belajar mengajar khususnya dalam meningkatkan hasil belajar siswa sangatlah lazim dilakukan karena untuk menciptakan kondisi pemebelajaran yang kondusif. Penelitian ini merupakan penelitian kualitatif kuantitatif dengan menggunakan metode deskriptif. Adapun Instrumen yang digunakan dalam penelitian ini adalah data kualitatif didapat melalui observasi, wawancara, studi dokumentasi dan studi kepustakaan. Untuk data kualitatif didapat melalui penyebaran lembar angket. Hasil penelitian menunjukkan bahwa Pemanfaatan lingkungan belajar pada mata pelajaran IPS telah dilakukan dan diterapkan oleh guru IPS di SMP N 1 Jalaksana Kabupaten Kuningan, ini terlihat jelas dengan hasil yang diperoleh adalah 47,25% (cukup). Respon siswa kelas VII di SMP N 1 Jalaksana Kabupaten Kuningan terhadap pembelajaran dengan menggunakan media lingkungan pada mata pelajaran IPS responya baik, ini terlihat jelas dengan hasil yang diperoleh adalah 44,5% (cukup). Hasil belajar siswa kelas VII di SMP N 1 Jalaksana Kabupaten dengan menggunakan lingkungan sebagai sumber belajar lebih meningkat hal ini dinyatakan oleh guru mata pelajaran IPS kelas VII sendiri melalui proses wawancara, dan hal ini juga terlihat jelas dari data hasil belajar siswa

Galactic cosmic rays on extrasolar Earth-like planets: II. Atmospheric implications

(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields. As described in the companion article (Paper I), a weak magnetic field results in a high flux of galactic cosmic rays to the top of the planetary atmosphere. We investigate effects that may result from a high flux of galactic cosmic rays both throughout the atmosphere and at the planetary surface. Using an air shower approach, we calculate how the atmospheric chemistry and temperature change under the influence of galactic cosmic rays for Earth-like (N_2-O_2 dominated) atmospheres. We evaluate the production and destruction rate of atmospheric biosignature molecules. We derive planetary emission and transmission spectra to study the influence of galactic cosmic rays on biosignature detectability. We then calculate the resulting surface UV flux, the surface particle flux, and the associated equivalent biological dose rates. We find that up to 20% of stratospheric ozone is destroyed by cosmic-ray protons. The reduction of the planetary ozone layer leads to an increase in the weighted surface UV flux by two orders of magnitude under stellar UV flare conditions. The resulting biological effective dose rate is, however, too low to strongly affect surface life. We also examine the surface particle flux: For a planet with a terrestrial atmosphere, a reduction of the magnetic shielding efficiency can increase the biological radiation dose rate by a factor of two. For a planet with a weaker atmosphere (with a surface pressure of 97.8 hPa), the planetary magnetic field has a much stronger influence on the biological radiation dose, changing it by up to two orders of magnitude.Comment: 14 pages, 9 figures, published in A&

Warm tachyonic inflation in warped background

We analyze warm tachyonic inflation, proposed in the literature, but from the viewpoint of four dimensional effective action for tachyon field on a non-BPS D3-brane. We find that consistency with observational data on density perturbation and validity of effective action requires warped compactification. The number of background branes which source the flux is found to be of the order of 10 in contrast to the order of $10^{14}$ in the standard cold inflationary scenario.Comment: 9 pages, RevTe

Ultra-high neutrino fluxes as a probe for non-standard physics

We examine how light neutrinos coming from distant active galactic nuclei (AGN) and similar high energy sources may be used as tools to probe non-standard physics. In particular we discuss how studying the energy spectra of each neutrino flavour coming from such distant sources and their distortion relative to each other may serve as pointers to exotic physics such as neutrino decay, Lorentz symmetry violation, pseudo-Dirac effects, CP and CPT violation and quantum decoherence. This allows us to probe hitherto unexplored ranges of parameters for the above cases, for example lifetimes in the range $10^{-3}-10^{4}$ s/eV for the case of neutrino decay. We show that standard neutrino oscillations ensure that the different flavours arrive at the earth with similar shapes even if their flavour spectra at source may differ strongly in both shape and magnitude. As a result, observed differences between the spectra of various flavours at the detector would be signatures of non-standard physics altering neutrino fluxes during propagation rather than those arising during their production at source. Since detection of ultra-high energy (UHE) neutrinos is perhaps imminent, it is possible that such differences in spectral shapes will be tested in neutrino detectors in the near future. To that end, using the IceCube detector as an example, we show how our results translate to observable shower and muon-track event rates.Comment: 16 pages, 10 figure

Universal Scaling of Wave Propagation Failure in Arrays of Coupled Nonlinear Cells

We study the onset of the propagation failure of wave fronts in systems of coupled cells. We introduce a new method to analyze the scaling of the critical external field at which fronts cease to propagate, as a function of intercellular coupling. We find the universal scaling of the field throughout the range of couplings, and show that the field becomes exponentially small for large couplings. Our method is generic and applicable to a wide class of cellular dynamics in chemical, biological, and engineering systems. We confirm our results by direct numerical simulations.Comment: 4 pages, 3 figures, RevTe

Pattern and Outcome of Chest Injuries at Bugando Medical Centre in Northwestern Tanzania.

Chest injuries constitute a continuing challenge to the trauma or general surgeon practicing in developing countries. This study was conducted to outline the etiological spectrum, injury patterns and short term outcome of these injuries in our setting. This was a prospective study involving chest injury patients admitted to Bugando Medical Centre over a six-month period from November 2009 to April 2010 inclusive. A total of 150 chest injury patients were studied. Males outnumbered females by a ratio of 3.8:1. Their ages ranged from 1 to 80 years (mean = 32.17 years). The majority of patients (72.7%) sustained blunt injuries. Road traffic crush was the most common cause of injuries affecting 50.7% of patients. Chest wall wounds, hemothorax and rib fractures were the most common type of injuries accounting for 30.0%, 21.3% and 20.7% respectively. Associated injuries were noted in 56.0% of patients and head/neck (33.3%) and musculoskeletal regions (26.7%) were commonly affected. The majority of patients (55.3%) were treated successfully with non-operative approach. Underwater seal drainage was performed in 39 patients (19.3%). One patient (0.7%) underwent thoracotomy due to hemopericardium. Thirty nine patients (26.0%) had complications of which wound sepsis (14.7%) and complications of long bone fractures (12.0%) were the most common complications. The mean LOS was 13.17 days and mortality rate was 3.3%. Using multivariate logistic regression analysis, associated injuries, the type of injury, trauma scores (ISS, RTS and PTS) were found to be significant predictors of the LOS (P < 0.001), whereas mortality was significantly associated with pre-morbid illness, associated injuries, trauma scores (ISS, RTS and PTS), the need for ICU admission and the presence of complications (P < 0.001). Chest injuries resulting from RTCs remain a major public health problem in this part of Tanzania. Urgent preventive measures targeting at reducing the occurrence of RTCs is necessary to reduce the incidence of chest injuries in this region

Pengaruh Motivasi Bermain Sepak Bola Melalui Representasi Serial Animasi Captain Tsubasa The Movie Terhadap Siswa

Tujuan penelitian ini adalah untuk Pengaruh motivasi bermain sepak bola melalui representasi dalam serial animasi Captain Tsubasa The Movie terhadap siswa kelas VII SMP N 22 Kota Jambi. Jenis penelitian yang digunakan adalah kualitatif deskriptif. Dengan menggunakan metode analisis atau disebut juga Content analysis yang berarti mengkaji pesan-pesan dalam media yang akan menghasilkan suatu kesimpulan tentang kecenderungan isi, tema dan lain sebagainya. Penelitian kualitatif deskriptif merupakan analisis isi yang menggambarkan secara detail suatu teks tertentu. Hasil perhitungan di atas dapat disimpulkan bahwa representasi motivasi bermain sepak bola yang terkandung dalam serial animasi Captain Tsubasa The Movie 1-2 terhadap siswa termasuk dalam kategori sangat baik dengan besaran persentase sebesar 85% yang mana nilai tersebut berada dalam rentang interval antara 81-100%. Kesimpulan dalam penelitian ini adalah representasi motivasi bermain sepak bola yang terkandung dalam serial animasi Captain Tsubasa The Movie 1-2 terhadap siswa kelas VII SMP N 22 Kota Jambi termasuk dalam kategori sangat baik dengan besaran persentase sebesar 85% yang mana nilai tersebut berada dalam rentang interval antara 81-100%. Kata kunci: Motivasi, Sepak bola, Captain Tsubasa The MovieTujuan penelitian ini adalah untuk Pengaruh motivasi bermain sepak bola melalui representasi dalam serial animasi Captain Tsubasa The Movie terhadap siswa kelas VII SMP N 22 Kota Jambi. Jenis penilitian yang digunakan adalah kualitatif deskriptif. Dengan menggunakan metode analisis atau disebut juga Content analysis yang berarti mengkaji pesan-pesan dalam media yang akan menghasilkan suatu kesimpulan tentang kecenderungan isi, tema dan lain sebagainya. Penilitian kualitatif deskriptif merupakan analisis isi yang menggambarkan secara detail suatu teks tertentu. Hasil perhitungan di atas dapat disimpulkan bahwa representasi motivasi bermain sepak bola yang terkandung dalam serial animasi Captain Tsubasa The Movie 1-2 terhadap siswa termasuk dalam kategori sangat baik dengan besaran porsentase sebesar 85% yang mana nilai tersebut berada dalam rentang interval antara 81-100%. Kesimpulan dalam penelitian ini adalah representasi motivasi bermain sepak bola yang terkandung dalam serial animasi Captain Tsubasa The Movie 1-2 terhadap siswa kelas VII SMP N 22 Kota Jambi termasuk dalam kategori sangat baik dengan besaran porsentase sebesar 85% yang mana nilai tersebut berada dalam rentang interval antara 81-100%. Kata kunci: Motivasi, Sepak bola, Captain Tsubasa The Movi

Non-minimally Coupled Tachyonic Inflation in Warped String Background

We show that the non-minimal coupling of tachyon field to the scalar curvature, as proposed by Piao et al, with the chosen coupling parameter does not produce the effective potential where the tachyon field can roll down from T=0 to large $T$ along the slope of the potential. We find a correct choice of the parameters which ensures this requirement and support slow-roll inflation. However, we find that the cosmological parameter found from the analysis of the theory are not in the range obtained from observations. We then invoke warped compactification and varying dilaton field over the compact manifold, as proposed by Raeymaekers, to show that in such a setup the observed parameter space can be ensured.Comment: minor typos corrected and references adde