Updated CMB constraints on Dark Matter annihilation cross-sections

The injection of secondary particles produced by Dark Matter (DM) annihilation at redshift 100<z<1000 affects the process of recombination, leaving an imprint on Cosmic Microwave Background (CMB) anisotropies. Here we provide a new assessment of the constraints set by CMB data on the mass and self-annihilation cross-section of DM particles. Our new analysis includes the most recent WMAP (7-year) and ACT data, as well as an improved treatment of the time-dependent coupling between the DM annihilation energy with the thermal gas. We show in particular that the improved measurement of the polarization signal places already stringent constraints on light DM particles, ruling out 'thermal' WIMPs with mass less then about 10 GeV.Comment: 4 pages, 1 figur

CMB constraints on Dark Matter models with large annihilation cross-section

The injection of secondary particles produced by Dark Matter (DM) annihilation around redshift 1000 would inevitably affect the process of recombination, leaving an imprint on Cosmic Microwave Background (CMB) anisotropies and polarization. We show that the most recent CMB measurements provided by the WMAP satellite mission place interesting constraints on DM self-annihilation rates, especially for models that exhibit a large Sommerfeld enhancement of the annihilation cross-section, as recently proposed to fit the PAMELA and ATIC results. Furthermore, we argue that upcoming CMB experiments such as Planck, will improve the constraints by at least one order of magnitude, thus providing a sensitive probe of the properties of DM particles

Using the Oxford Cognitive Screen to detect cognitive impairment in stroke patients: a comparison with the Mini-Mental State Examination

Background: The Oxford Cognitive Screen (OCS) was recently developed with the aim of describing the cognitive deficits after stroke. The scale consists of 10 tasks encompassing five cognitive domains: attention and executive function, language, memory, number processing, and praxis. OCS was devised to be inclusive and un-confounded by aphasia and neglect. As such, it may have a greater potential to be informative on stroke cognitive deficits of widely used instruments, such as the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment, which were originally devised for demented patients. Objective: The present study compared the OCS with the MMSE with regards to their ability to detect cognitive impairments post-stroke. We further aimed to examine performance on the OCS as a function of subtypes of cerebral infarction and clinical severity. Methods: 325 first stroke patients were consecutively enrolled in the study over a 9-month period. The OCS and MMSE, as well as the Bamford classification and NIHSS, were given according to standard procedures. Results: About a third of patients (35.3%) had a performance lower than the cutoff (<22) on the MMSE, whereas 91.6% were impaired in at least one OCS domain, indicating higher incidences of impairment for the OCS. More than 80% of patients showed an impairment in two or more cognitive domains of the OCS. Using the MMSE as a standard of clinical practice, the comparative sensitivity of OCS was 100%. Out of the 208 patients with normal MMSE performance 180 showed impaired performance in at least one domain of the OCS. The discrepancy between OCS and MMSE was particularly strong for patients with milder strokes. As for subtypes of cerebral infarction, fewer patients demonstrated widespread impairments in the OCS in the Posterior Circulation Infarcts category than in the other categories. Conclusion: Overall, the results showed a much higher incidence of cognitive impairment with the OCS than with the MMSE and demonstrated no false negatives for OCS vs MMSE. It is concluded that OCS is a sensitive screen tool for cognitive deficits after stroke. In particular, the OCS detects high incidences of stroke-specific cognitive impairments, not detected by the MMSE, demonstrating the importance of cognitive profiling

A quantitative approach in the treatment of hemiplegic patients using an electropneumatic platform

Exercise is the central feature in the rehabilitative treatment of hemiplegic patients. In cognitive rehabilitation, great importance is attributed to the recovery of a sufficient number of proprioceptive channels before expecting the patient to regain voluntary control. The PERM [Piattaforma (Platform), Elettropneumatica (Electropneumatic) per (for) Riabilitazione (Rehabilitation) Motoria (Motor)] is a new device that can be used in the treatment of the lower limbs to provide the patient with controlled and quantifiable mechanical stimuli, thus enabling the therapist to adopt a more rigourous approach to treatment even in the very early stages of rehabilitation. Alternatively, the system can be used in a different operating mode as a normal biofeedback system capable of displaying on-screen the extent to which voluntary load has been transferred to the lower limb. Exercise is the central feature in the rehabilitative treatment of hemiplegic patients. In cognitive rehabilitation, great importance is attributed to the recovery of a sufficient number of proprioceptive channels before expecting the patient to regain voluntary control. The PERM [Piattaforma (Platform), Elettropneumatica (Electropneumatic) per (for) Riabilitazione (Rehabilitation) Motoria (Motor)] is a new device that can be used in the treatment of the lower limbs to provide the patient with controlled and quantifiable mechanical stimuli, thus enabling the therapist to adopt a more rigorous approach to treatment even in the very early stages of rehabilitation. Alternatively, the system can be used in a different operating mode as a normal biofeedback system capable of displaying on-screen the extent to which voluntary load has been transferred to the lower limb

Handling the Uncertainties in the Galactic Dark Matter Distribution for Particle Dark Matter Searches

International audienceIn this work we characterize the distribution of Dark Matter (DM) in the Milky Way (MW), and its uncertainties, adopting the well known "Rotation Curve" method. We perform a full marginalization over the uncertainties of the Galactic Parameters and over the lack of knowledge on the morphology of the baryonic components of the Galaxy. The local DM density ρ0 is constrained to the range 0.3– 0.8 GeV/cm3 at the 2 σ level, and has a strong positive correlation to R0, the local distance from the Galactic Center. The not well-known value of R0 is thus, at the moment, a major limitation in determining ρ0. Similarly, we find that the inner slope of the DM profile, γ, is very weakly constrained, showing no preference for a cored profile (γ  0) or a cuspy one (γ [1.0,1.4]). Some combination of parameters can be, however, strongly constrained. For example the often used standard ρ0=0.3 GeV/cm3, R0=8.5 kpc is excluded at more than 4 σ. We release the full likelihood of our analysis in a tabular form over a multidimensional grid in the parameters characterizing the DM distribution, namely the scale radius Rs, the scale density ρs, the inner slope of the profile γ, and R0. The likelihood can be used to include the effect of the DM distribution uncertainty on the results of searches for an indirect DM signal in gamma-rays or neutrinos, from the Galactic Center (GC), or the Halo region surrounding it. As one example, we study the case of the GC excess in gamma rays. Further applications of our tabulated uncertainties in the DM distribution involve local DM searches, like direct detection and anti-matter observations, or global fits combining local and GC searches