Bounds on Dark Matter decay from 21 cm line

The observation of the cosmic 21-cm spectrum can serve as a probe for Dark Matter properties. We point out that the knowledge of the signal amplitude at a given redshift allows one to put conservative bounds on the DM decay rate which are independent of astrophysical parameters. These limits are valid for the vast majority of DM models, those without extra IGM cooling or additional background radiation. Using the experimental results reported by the EDGES collaboration, we derive bounds that are stronger than the ones derived from other CMB observations and competitive with the ones from indirect detection.Comment: 9 pages, 2 figures. v3: Improved discussion of the assumptions, matching to the published version. Bounds for different decay channels included. References adde

Gluequark Dark Matter

We introduce the gluequark Dark Matter candidate, an accidentally stable bound state made of adjoint fermions and gluons from a new confining gauge force. Such scenario displays an unusual cosmological history where perturbative freeze-out is followed by a non-perturbative re-annihilation period with possible entropy injection. When the gluequark has electroweak quantum numbers, the critical density is obtained for masses as large as PeV. Independently of its mass, the size of the gluequark is determined by the confinement scale of the theory, leading at low energies to annihilation rates and elastic cross sections which are large for particle physics standards and potentially observable in indirect detection experiments.Comment: 39 pages, 7 figures. v2: improved discussion of theoretical uncertainties, matching to the published version. References added and typos fixe

Study the effect of beam energy spread and detector resolution on the search for Higgs boson decays to invisible particles at a future e+^+e−^- circular collider

We study the expected sensitivity to measure the branching ratio of Higgs boson decays to invisible particles at a future circular \epem collider (FCC-ee) in the process $e^+e^-\to HZ$ with $Z\to \ell^+\ell^-$ ($\ell=e$ or $\mu$) using an integrated luminosity of 3.5 ab$^{-1}$ at a center-of-mass energy $\sqrt{s}=240$ GeV. The impact of the energy spread of the FCC-ee beam and of the resolution in the reconstruction of the leptons is discussed. %Two different detector concepts are considered: a detector corresponding to the CMS reconstruction performances and the expected design of the ILC detector. The minimum branching ratio for a $5\sigma$ observation after 3.5ab$^{-1}$ of data taking is $1.7\pm 0.1\%(stat+syst)$. The branching ratio exclusion limit at 95\% CL is $0.63 \pm 0.22\%((stat+syst))$.Comment: 17 pages, submitted to EPJ

Changes in total choline concentration in the breast of healthy fertile young women in relation to menstrual cycle or use of oral contraceptives: a 3-T 1H-MRS study

BACKGROUND: To evaluate changes in total choline (tCho) absolute concentration ([tCho]) in the breast of healthy fertile women in relation to menstrual cycle (MC) or use of oral contraceptives (OC). METHODS: After institutional review board approval, we prospectively evaluated 40 healthy fertile volunteers: 20 with physiological MC, aged 28 ± 3 years (mean ± standard deviation; nOC group); 20 using OC, aged 26 ± 3 years (OC group). Hormonal assays and water-suppressed single-voxel 3-T proton magnetic resonance spectroscopy (1H-MRS) were performed on MC days 7, 14, and 21 in the nOC group and only on MC day 14 in the OC group. [tCho] was measured versus an external phantom. Mann-Whitney U test and Spearman coefficient were used; data are given as median and interquartile interval. RESULTS: All spectra had good quality. In the nOC group, [tCho] (mM) did not change significantly during MC: 0.8 (0.3-2.4) on day 7, 0.9 (0.4-1.2) on day 14, and 0.4 (0.2-0.8) on day 21 (p = 0.963). In the OC group, [tCho] was 0.7 (0.2-1.7) mM. The between-groups difference was not significant on all days (p ≥ 0.411). All hormones except prolactin changed during MC (p ≤ 0.024). In the OC group, [tCho] showed a borderline correlation with estradiol (r = 0.458, p = 0.056), but no correlation with other hormones (p ≥ 0.128). In the nOC group, [tCho] negatively correlated with prolactin (r = -0.587, p = 0.006) on day 7; positive correlation was found with estradiol on day 14 (r = 0.679, p = 0.001). CONCLUSIONS: A tCho peak can be detected in the normal mammary gland using 3-T 1H-MRS. The [tCho] in healthy volunteers was 0.4-0.9 mM, constant over the MC and independent of OC use

Pengaruh Terapi Pijat Refleksi Kaki Terhadap Ankle Brachial Index (Abi) Pada Pasien Diabetes Melitus Tipe 2

Diabetes melitus adalah suatu penyakit kronis yang merupakan masalah kesehatan dunia yang serius. World Health Organization (WHO) memperkirakan di Asia Tenggara ada 30 juta penderita DM pada tahun 2000 dan diprediksi akan meningkat sampai 80 juta pada tahun 2025. Jumlah ini merupakan yang tertinggi di dunia (Wild, et al., 2009). Diabetes melitus merupakan sekelompok kelainan heterogen yang ditandai oleh kenaikan kadar glukosa dalam darah atau hiperglikemia (Smeltzer & Bare, 2010). Saat ini angka pasien diabetes melitus bertambah banyak, WHO memprediksi bahwa pada tahun 2000 jumlah pengidap diabetes di atas umur 20 tahun berjumlah 150 juta orang di dunia dan dalam kurun waktu 25 tahun kemudian, pada tahun 2025 jumlah tersebut akan membengkak menjadi 300 juta orang. Diabetes melitus di Indonesia diprediksi mengalami kenaikan jumlah pasien dari 8,4 juta pada tahun 2000 menjadi sekitar 21,3 juta pada tahun 2030Penelitian ini bertujuan untuk mengetahui pengaruh terapi pijat refleksi kaki terhadap ankle brachial index (ABI) pada pasien diabetesmelitus tipe 2.Penelitian ini menggunakan rancangan eksperimen semu dengan desain pre test- post test design. Respondennya 64 pasien diabetes melitus tipe 2 yang dirawat jalan di RS PKU Muhammadiyah Gombong pada bulan Mei 2014, terdiri dari 32 responden kontrol dan 32 responden intervensi. Teknik pengumpulan datanya menggunakan pengukuran dan dokumentasi dengan bantuan instrumen doppler Ultrasound 8MHz dan Sphygnomano meter, lembar dokumentasi karakteristik responden, lembar pengukuran ABI, panduan pemeriksaan ABI, dan panduan pijat refleksi kaki. Teknik analisis datanya menggunakan Paired t Test dan t Test, yang sebelumnya telah dilakukan uji prasyarat analisis meliputi uji normalitas, homogenitas, dan kesetaraan.Setelah dilakukan analisis diperoleh hasil terapi pijat refleksi kaki berpengaruh signifikan dalam meningkatkan ankle brachial index (ABI) pada pasien diabetes melitus tipe 2 di RS PKU Muhammadiyah Gombong, terbukti dari: (a) terjadi peningkatan ABI yang signifikan pada kelompok intervensi; (b) tidak terjadi peningkatan ABI yang signifikan pada kelompok kontrol; (c) sesudah penelitian ABI kelompok intervensi secara signifikan lebih tinggi dibandingkan ABI kelompok kontrol; (d) peningkatan ABI kelompok intervensi secara signifikan lebih tinggi dibandingkan peningkatan ABI kelompok kontrol

Topics in composite models and dark matter phenomenology

We investigate models of composite dark matter in which the dark matter candidate arises naturally as an accidentally stable bound state of a confining dynamics and with observable signatures in a wide variety of experiments. In the first part of the thesis we introduce and explore a new class of models with dark fermions in the adjoint repre- sentation of the confining gauge group. The low energy dynamics and the cosmological history are peculiar and provide a dark matter candidate with properties much different from that of a canonical WIMP. The dark matter is heavy but has a large interaction range and can be tested primarily with indirect searches. In the second part of the thesis we classify and study models of composite dark matter with a strongly interacting chiral dark sector, in which all the mass scales are generated dynamically. In this case the candidate is a SM singlet dark pion with a thermal abundance whose low energy phenomenology can be thoroughly studied through chiral lagrangian techniques. We present an analysis of the low energy phenomenology, compute the radiatively generated masses of the light states and study the cosmological history of the model. The presence of partner states interacting with the SM offers the opportunity to test the model at colliders. In the last part of the thesis we present the phenomenological signatures of the models previously introduced and determine the current bounds. In doing so we also present a strategy to derive a limit on the lifetime of dark matter particles in generic models of particle dark matter from the observation of the 21 cm cosmological signal

Fermions at finite density in the path integral approach

We study relativistic fermionic systems in $3+1$ spacetime dimensions at finite chemical potential and zero temperature, from a path-integral point of view. We show how to properly account for the $i\varepsilon$ term that projects on the finite density ground state, and compute the path integral analytically for free fermions in homogeneous external backgrounds, using complex analysis techniques. As an application, we show that the ${\rm U}(1)$ symmetry is always linearly realized for free fermions at finite charge density, differently from scalars. We study various aspects of finite density QED in a homogeneous magnetic background. We compute the free energy density, non-perturbatively in the electromagnetic coupling and the external magnetic field, obtaining the finite density generalization of classic results of Euler--Heisenberg and Schwinger. We also obtain analytically the magnetic susceptibility of a relativistic Fermi gas at finite density, reproducing the de Haas--van Alphen effect. Finally, we consider a (generalized) Gross--Neveu model for $N$ interacting fermions at finite density. We compute its non-perturbative effective potential in the large-$N$ limit, and discuss the fate of the ${\rm U}(1)$ vector and $\mathbb{Z}_2^A$ axial symmetries.Comment: 34 pages, 6 figures. v2: one reference added, matches published versio

Automatic quality assessment in structural brain magnetic resonance imaging

MRI has evolved into an important diagnostic technique in medical imaging. However, reliability of the derived diagnosis can be degraded by artifacts, which challenge both radiologists and automatic computer-aided diagnosis. This work proposes a fully-automatic method for measuring image quality of three-dimensional (3D) structural MRI. Quality measures are derived by analyzing the air background of magnitude images and are capable of detecting image degradation from several sources, including bulk motion, residual magnetization from incomplete spoiling, blurring, and ghosting. The method has been validated on 749 3D T(1)-weighted 1.5T and 3T head scans acquired at 36 Alzheimer's Disease Neuroimaging Initiative (ADNI) study sites operating with various software and hardware combinations. Results are compared against qualitative grades assigned by the ADNI quality control center (taken as the reference standard). The derived quality indices are independent of the MRI system used and agree with the reference standard quality ratings with high sensitivity and specificity (>85%). The proposed procedures for quality assessment could be of great value for both research and routine clinical imaging. It could greatly improve workflow through its ability to rule out the need for a repeat scan while the patient is still in the magnet bore