Quasinormal Modes Beyond Kerr

The quasinormal modes (QNMs) of a black hole spacetime are the free, decaying oscillations of the spacetime, and are well understood in the case of Kerr black holes. We discuss a method for computing the QNMs of spacetimes which are slightly deformed from Kerr. We mention two example applications: the parametric, turbulent instability of scalar fields on a background which includes a gravitational QNM, and the shifts to the QNM frequencies of Kerr when the black hole is weakly charged. This method may be of use in studies of black holes which are deformed by external fields or are solutions to alternative theories of gravity.Comment: Proceedings of the Sant Cugat Forum on Astrophysics (2014). Session on 'Gravitational Wave Astrophysics.' 7 page

Testing strong gravity with gravitational waves and Love numbers

The LIGO observation of GW150914 has inaugurated the gravitational-wave astronomy era and the possibility of testing gravity in extreme regimes. While distorted black holes are the most convincing sources of gravitational waves, similar signals might be produced also by other compact objects. In particular, we discuss what the gravitational-wave ringdown could tell us about the nature of the emitting object, and how measurements of the tidal Love numbers could help us in understanding the internal structure of compact dark objects

Pengaruh Customer Perception, Perceived Value, Price dan Promotion terhadap Buying Decision pada Tiket Lion Air

Penelitian ini bertujuan untuk mengetahui pengaruh customer perception, perceived value, price dan promotion terhadap buying decision pada tiket Lion Air. Metode yang digunakan dalam penelitian ini yaitu metode penelitian kuantitatif. Sampel dalam penelitian ini sebanyak 100 orang responden yang diambil dengan metode purposive sampling. Analisis data akan dilakukan dengan menggunakan alat uji statistik dengan bantuan aplikasi bernama Statistical Product and Service Solutions (SPSS). Hasil penelitian menunjukkan bahwa customer perception, perceived value, price dan pro- motion berpengaruh positif dan signifikan terhadap buying decision

A multi-layer edge-on single photon counting silicon microstrip detector for innovative techniques in diagnostic radiology

A three-layer detector prototype, obtained by stacking three edge-on single photon counting silicon microstrip detectors, has been developed and widely tested. This was done in the framework of the Synchrotron Radiation for Medical Physics/Frontier Radiology (SYRMEP/FRONTRAD) collaboration activities, whose aim is to improve the quality of mammographic examinations operating both on the source and on the detector side. The active surface of the device has been fully characterized making use of an edge-scanning technique and of a well-collimated laminar synchrotron radiation beam. The obtained data (interlayer distances, channel correspondence, etc.) have then been used to combine information coming from each detector layer, without causing any loss in spatial and contrast resolution of the device. Contrast and spatial resolution have also been separately evaluated for each detector layer. Moreover, imaging techniques (phase contrast, refraction, and scatter imaging), resulting in an increased visibility of low absorbing details, have been implemented, and their effectiveness has been tested on a biological sample. Finally, the possibility of simultaneously acquiring different kind of images with the different detector layers is discussed. This would result in maximizing the information extracted from the sample, while at the same time the high absorption efficiency of the detector device would allow a low dose delivery

Gravitational waves from extreme mass-ratio inspirals in Dynamical Chern-Simons gravity

Dynamical Chern-Simons gravity is an interesting extension of General Relativity, which finds its way in many different contexts, including string theory, cosmological settings and loop quantum gravity. In this theory, the gravitational field is coupled to a scalar field by a parity-violating term, which gives rise to characteristic signatures. Here we investigate how Chern-Simons gravity would affect the quasi-circular inspiralling of a small, stellar-mass object into a large non-rotating supermassive black hole, and the accompanying emission of gravitational and scalar waves. We find the relevant equations describing the perturbation induced by the small object, and we solve them through the use of Green's function techniques. Our results show that for a wide range of coupling parameters, the Chern-Simons coupling gives rise to an increase in total energy flux, which translates into a fewer number of gravitational-wave cycles over a certain bandwidth. For space-based gravitational-wave detectors such as LISA, this effect can be used to constrain the coupling parameter effectively.Comment: RevTex4, 18 pages, 7 figures, 1 tabl

Gravitational instabilities of superspinars

Superspinars are ultracompact objects whose mass M and angular momentum J violate the Kerr bound (cJ/GM^2>1). Recent studies analyzed the observable consequences of gravitational lensing and accretion around superspinars in astrophysical scenarios. In this paper we investigate the dynamical stability of superspinars to gravitational perturbations, considering either purely reflecting or perfectly absorbing boundary conditions at the "surface" of the superspinar. We find that these objects are unstable independently of the boundary conditions, and that the instability is strongest for relatively small values of the spin. Also, we give a physical interpretation of the various instabilities that we find. Our results (together with the well-known fact that accretion tends to spin superspinars down) imply that superspinars are very unlikely astrophysical alternatives to black holes.Comment: 15 pages, 9 figures, 1 table. v2: Fig. 8 and Section I improved. v3: minor changes to match the published versio

Dark photon superradiance quenched by dark matter

Black-hole superradiance has been used to place very strong bounds on avariety of models of ultralight bosons such as axions, new light scalars, anddark photons. It is common lore to believe that superradiance bounds arebroadly model independent and therefore pretty robust. In this work we showhowever that superradiance bounds on dark photons can be challenged by simple,compelling extensions of the minimal model. In particular, if the dark photonpopulates a larger dark sector and couples to dark fermions playing the role ofdark matter, then superradiance bounds can easily be circumvented, depending onthe mass and (dark) charge of the dark matter.<br

ANALISIS MIKROBIOLOGI DAN HIGIENE SANITASI PADA DEPOT AIR MINUM DI WILAYAH KERJA PUSKESMAS BAHU KOTA MANADO

Air merupakan salah satu kebutuhan hidup manusia di bumi, namun seiring dengan perkembangan penduduk, kebutuhan air bersih semakin besar pula, sehingga ketersediaan air bersih sudah mulai berkurang akibat kerusakan lingkungan atau pencemaran lingkungan yang disebabkan oleh penduduk sekitar dan penduduk mencari berbagai alternatif air bersih untuk di minum dengan mengkomsumsi air minum isi ulang dari pengusaha depot air minum dalam memenuhi kebutuhan air minum. Tujuan penelitian ini untuk mengetahui kualitas air minum depot berdasarkan parameter mikrobiologi dan higiene sanitasi DAM di wilayah kerja puskesmas Bahu. Jenis penelitian ini merupakan penelitian deskriptif dengan pendekatan observasional yang menggunakan uji laboratorium dengan jumlah sampel yaitu 11 DAM dan menganalisis kualitas mikrobiologi air minum dan observasi DAM menggunakan kuesioner format pemeriksaan fisik hygiene sanitasi DAM. Hasil penelitian dari pemeriksaan mikrobiologi kualitasi air minum pada 11 DAM terdapat 4 DAM (36,4%) tercemar bakteri Escherichia Coli dan 6 DAM (54,5%) tercemar bakteri Coliform, dinyatakan tidak memenuhi syarat kualitas air minum jika tidak sesuai dengan PERMENKES RI Nomor. 492/MENKES/PER/IV/2010, dimana standar yang di tetapkan adalah bakteri Escherichia Coli, Coliform sama dengan 0/100 ml air. Hasil penilaian higiene sanitasi fisik DAM menunjukkan bahwa dari 11 DAM yang diteliti terdapat 6 DAM (54,5%) tidak memenuhi syarat kelaiakan fisik higiene sanitasi, yang di pengaruhi oleh faktor tempat, peralatan dan pejamah. Dikatakan memenuhi syarat apabila nilai bobot sudah mencapai 70 dan tidak memenuhi syarat apabila nilai bobot <70 sesuai dengan PERMENKES RI No.43 Tahun 2014.Kata Kunci: Kualitas Mikrobiologi, Higiene Sanitasi, DAMABSTRACTWater is one of the necessities of life on earth, but as the population grows, the need for clean water is growing, that the availability of fresh water has begun to decrease as a result of environmental damage or of environmental pollution caused by locals and people are looking for fresh water alternatives to drink by consuming water from the depot while supplying the drinking water needs. The purpose of this study was to determine the quality of DAM drinking water based on microbiology parameters and sanitation hygiene DAM in the area of the Bahu health center. This type of research is a descriptive study with observational approaches that used laboratory tests with the amount of samples that is 11 DAM and analyze the quality of the microbiology of drinking water and of DAM observation using questionnaire for mat examination of DAM sanitation hygiene. Studies show that a microbiology examination of the quality of drinking water at 11 DAM there were 4 DAM (36,4%) contaminated by Escherichia Coli and 6 DAM (54,5%) polluted with Coliform bacteria, it is not eligible for drinking water quality if it does not match with the PERMENKES RI No. 492/MENKES/PER/IV/2010, where the standard established is Escherichia Coli, Coliform is equivalent to 0/100 ml of water. The results of the physical sanitization assessment of the DAM indicate that from the 11 DAM there were 6 DAM (54,5%) physical hygiene does not quality, that are affected by place, equipment and decay. They say they qualify when they can put a weight of 70 and does not meet the requirements if the weigh value is <70 accordance with PERMEKES RI No. 43 of 2014.Keywords: Microbiology Quality, Sanitation Hygiene, DA