A graph of dark energy significance on different spatial and mass scales

The current cosmological paradigm sees the formation and evolution of the cosmic large-scale structure as governed by the gravitational attraction of the Dark Matter (DM) and the repulsion of the Dark Energy (DE). We characterize the relative importance of uniform and constant dark energy, as given by the Lambda term in the standard LCDM cosmology, in galaxy systems of different scales, from groups to superclusters. An instructive "Lambda significance graph" is introduced where the matter-DE density ratio /rho_Lambda for different galaxy systems is plotted against the radius R. This presents gravitation and DE dominated regions and shows directly the zero velocity radius, the zero-gravity radius, and the Einstein-Straus radius for any fixed value of mass. Example galaxy groups and clusters from the local universe illustrate the use of the Lambda significance graph. These are generally located deep in the gravity-dominated region /rho_Lambda > 2, being virialized. Extended clusters and main bodies of superclusters can reach down near the border line between gravity-dominated and DE dominated regions /rho_Lambda = 2. The scale--mass relation from the standard 2-point correlation function intersects this balance line near the correlation lenght. The log /rho_Lambda vs. log R diagram is a useful and versatile way to characterize the dynamical state of systems of galaxies within the Lambda dominated expanding universe.Comment: 4 pages, 2 figure

A fast 2D image reconstruction algorithm from 1D data for the Gaia mission

A fast 2-dimensional image reconstruction method is presented, which takes as input 1-dimensional data acquired from scans across a central source in different orientations. The resultant reconstructed images do not show artefacts due to non-uniform coverage in the orientations of the scans across the central source, and are successful in avoiding a high background due to contamination of the flux from the central source across the reconstructed image. Due to the weighting scheme employed this method is also naturally robust to hot pixels. This method was developed specifically with Gaia data in mind, but should be useful in combining data with mismatched resolutions in different directions.Comment: accepted (18 pages, 13 figures) will appear in Experimental Astronom

Shell-like structures in our cosmic neighbourhood

Signatures of the processes in the early Universe are imprinted in the cosmic web. Some of them may define shell-like structures characterised by typical scales. We search for shell-like structures in the distribution of nearby rich clusters of galaxies drawn from the SDSS DR8. We calculate the distance distributions between rich clusters of galaxies, and groups and clusters of various richness, look for the maxima in the distance distributions, and select candidates of shell-like structures. We analyse the space distribution of groups and clusters forming shell walls. We find six possible candidates of shell-like structures, in which galaxy clusters have maxima in the distance distribution to other galaxy groups and clusters at the distance of about 120 Mpc/h. The rich galaxy cluster A1795, the central cluster of the Bootes supercluster, has the highest maximum in the distance distribution of other groups and clusters around them at the distance of about 120 Mpc/h among our rich cluster sample, and another maximum at the distance of about 240 Mpc/h. The structures of galaxy systems causing the maxima at 120 Mpc/h form an almost complete shell of galaxy groups, clusters and superclusters. The richest systems in the nearby universe, the Sloan Great Wall, the Corona Borealis supercluster and the Ursa Major supercluster are among them. The probability that we obtain maxima like this from random distributions is lower than 0.001. Our results confirm that shell-like structures can be found in the distribution of nearby galaxies and their systems. The radii of the possible shells are larger than expected for a BAO shell (approximately 109 Mpc/h versus approximately 120 Mpc/h), and they are determined by very rich galaxy clusters and superclusters with high density contrast while BAO shells are barely seen in the galaxy distribution. We discuss possible consequences of these differences.Comment: Comments: 9 pages, 10 figures, Astronomy and Astrophysics, in pres

PENERAPAN MODEL PEMBELAJARAN STUDENT TEAMS ACHIEVEMENT DIVISION (STAD) MENGGUNAKAN E-MODUL UNTUK MENINGKATKAN HASIL BELAJAR SISWA PADA MATA PELAJARAN MEKANIKA TEKNIK KELAS X TGB SMK NEGERI 2 KRAKSAAN

Abstrak Pembelajaran kooperatif tipe Student Teams Achievement Divisio (STAD) merupakan model pembelajaran kooperatif dengan cara membentuk kelompok-kelompok kecil secara heterogen agar memacu siswa untuk saling mendorong dan membantu satu sama lain. E-modul merupakan suatu unit lengkap program pengajaran yang disajikan melalui perangkat elektronik dan software pembuka khusus, yang berisi komponen-komponen kegiatan belajar yang disusun untuk membantu siswa mencapai sejumlah tujuan yang khusus dan jelas secara mandiri. Tujuan penelitian untuk mengetahui peningkatan hasil belajar siswa, kegiatan mengajar guru, dan kegiatan belajar siswa di kelas dengan menerapkan model pembelajaran STAD menggunakan e-modul pada mata pelajaran mekanika teknik. Penelitian difokuskan pada aspek kognitif menganalisis gaya batang pada konstruksi rangka batang sederhana. Metode penelitian menggunakan Penelitian Tindakan Kelas (PTK), dengan menggunakan siklus dalam proses pembelajaran sampai nilai hasil belajar siswa mencapai kriteria ketuntasan minimum. Subjek penelitian adalah siswa kelas X TGB2 SMKN 2 Kraksaan. Teknik pengumpulan data yang digunakan adalah tes hasil belajar dan metode observasi. Hasil penelitian pada siklus 1 didapatkan nilai hasil belajar siswa 76,43 dengan persentase 58,33% siswa tuntas, meningkat pada siklus 2 nilai hasil belajar siswa 80,17 dengan persentase 86,11% siswa tuntas. Hasil kegiatan mengajar guru pada siklus 1 memperoleh skor rerata 3,35 (cukup baik), meningkat pada siklus 2 memperoleh skor rerata 3,70 (baik). Hasil kegiatan belajar siswa pada siklus 1 memperoleh skor rerata 3,23 (cukup baik), meningkat pada siklus 2 memperoleh skor rerata 3,69 (baik). Kesimpulan penelitian yaitu terjadi peningkatan pada hasil belajar siswa, kegiatan mengajar guru, dan kegiatan belajar siswa. Kata Kunci: STAD, e-modul, hasil belajar siswa, kegiatan mengajar guru, kegiatan belajar siswa. Abstract Student Teams Achievement Division (STAD) cooperative learning is a cooperative learning model by forming heterogeneous small groups in order to encourage students to encourage and help one another. E-module is a complete unit of teaching program that is presented through electronic devices and special opening software, which contains components of learning activities that are arranged to help students achieve a number of specific and clear objectives independently. The research objective is to determine the improvement of student learning outcomes, teacher teaching activities, and student learning activities in the classroom by applying the STAD learning model using e-modules in engineering mechanics subjects. The study focused on the cognitive aspects of analyzing rod style in simple truss construction. The research method uses Classroom Action Research (CAR), by using cycles in the learning process until the students learning outcomes reach the minimum completeness criteria. The research subjects were students of class X TGB2 of SMK 2 Kraksaan. Data collection techniques used are learning outcomes tests and observation methods. The results of the study in cycle 1 obtained the value of 76.43 student learning outcomes with a percentage of 58.33% of students completed, increasing in cycle 2 the value of student learning outcomes 80.17 with a percentage of 86.11% of students completed. The results of teacher teaching activities in cycle 1 gained a mean score of 3.35 (good enough), increasing in cycle 2 to obtain a mean score of 3.70 (good). The results of student learning activities in cycle 1 obtained a mean score of 3.23 (good enough), increasing in cycle 2 to obtain a mean score of 3.69 (good). The conclusion of the study is an increase in student learning outcomes, teacher teaching activities, and student learning activities. Keywords: STAD, e-module, student learning outcomes, teacher teaching activities, student learning activitie

Evaluation of minimal fracture liaison service resource : costs and survival in secondary fracture prevention-a prospective one-year study in South-Finland

Background Fracture liaison service (FLS) is a secondary prevention model for identification of patients at risk for fragility fractures. Aims This study was conducted to evaluate the number and costs of secondary prevention of low-energy fractures in the city of Kouvola in Finland. Methods Women aged >= 45 years and men >= 60 years treated in the emergency department with a low-energy fracture were identified. Laboratory testing, BMI, and DXA scans were performed. Fracture Risk Assessment Tool was used. The direct FLS costs were calculated. Survival was analyzed using univariate and multivariate analysis and the life-table method. Results 525 patients with 570 fractures were identified. The mean age of women was 73.8 years and of men 75.9 years. Most patients sustained wrist (31%), hip (21%) or proximal humerus (12%) fractures. 41.5% of the patients had osteoporosis according to DXA scans. 62% of patients used calcium and vitamin D daily and 38% started anti-osteoporotic medication. Protective factors for survival were: age <80 years, female sex, and S-25OHD concentration of 50-119 nmol/L. Excess mortality was highest among patients with a fracture of the femur. The total annual direct costs of FLS were 1.3% of the costs of all fractures. Discussion Many low-energy fracture types were associated with excess mortality. The use of anti-osteoporotic medication was not optimal. Conclusions FLS increased the catchment of low-energy fracture patients and was inexpensive. However, identification, evaluation and post-fracture assessment of patients should be expedited. Rehabilitation of hip fracture patients needs to be improved.Peer reviewe

Shining primordial black holes

We study the well-motivated mixed dark matter (DM) scenario composed of a dominant thermal WIMP, highlighting the case of SU(2)(L) triplet fermion "winos," with a small fraction of primordial black holes (PBHs). After the wino kinetic decoupling, the DM particles are captured by PBHs leading to the presence of PBHs with dark minihalos in the Milky Way today. The strongest constraints for the wino DM come from the production of narrow line gamma rays from wino annihilation in the Galactic Center. We analyse in detail the viability of the mixed wino DM scenario, and determine the constraints on the fraction of DM in PBHs assuming a cored halo profile in the Milky Way. We show that already with the sensitivity of current indirect searches, there is a significant probability for detecting a gamma ray signal characteristic for the wino annihilation in a single nearby dressed PBH when M-PBH similar to M-circle dot, which we refer to as a "shining black hole." Similar results should apply also in more general setups with ultracompact minihalos or other DM models, since the accretion of DM around large overdensities and DM annihilation are both quite generic processes.Peer reviewe

A 10-Year Retrospective Study of 490 Hip Fracture Patients: Reoperations, Direct Medical Costs, and Survival

Background and Aims: Reoperations after operative treatment of hip fracture patients may be associated with higher costs and inferior survival. We examined the acute hospital costs, long-term reoperation rates, and survival of patients with a new hip fracture. Materials and Methods: A total of 490 consecutive new hip fracture patients treated at a single center between 31 December 2004 and 6 December 2006 were analyzed retrospectively. Fractures were classified according to Garden and AO. All medical records were checked manually. The costs of reoperations were calculated using the diagnosis-related groups (DRG)-based prices. Survival analysis was performed using the life-table method. The follow-up time was 10 years. Results: In all, 70/490 patients (14.3%) needed reoperations. Of all reoperations, 34.2% were performed during the first month and 72.9% within 1 year after the primary operation. The hemiarthroplasty dislocation rate was 8.5%, and mechanical failures of osteosynthesis occurred in 6.2%. Alcohol abuse was associated with a heightened risk of reoperation. The mean direct costs of primary fracture care were lower than the mean costs of reoperations (euro7500 vs euro9800). The mortality rate at 10 years was 79.8% among non-reoperated patients and 62.9% among reoperated patients. Conclusions: According to our hypothesis, the cost per patient of reoperation in acute care was 31% higher than the corresponding cost of a primary operation. Reoperations increased the overall immediate costs of index fractures by nearly 20%. One-third of all reoperations were performed during the first month and almost 75% within 1 year after the primary operation.Peer reviewe