Exploring the sources of innovation: the case of Hackathon

This paper advances the exploration of the sources of innovation through the characteristics of the objects produced. To achieve a greater openness to the un- known of innovation processes, we choose not to examine final products. While, as put by von Hippel, final products embed in their functions a value (of use or of exchange), they hide the non-deterministic nature of the process, implying that the goal was known from the beginning. Instead, we will examine poten- tial products, that means projects that have not yet concluded to the market, neither have they been used. Investigating the contributions at a Hackathon hosted by Google, we induce three categories of innovative attitude: collective intimacy, entrepreneurial thinking and technological avant-garde

Spectrometry for Analysis of Acylcarnitines in Dried Postmortem Blood Specimens Collected at

7. Feinstein JA, O'Brien K. “Acute metabolic decompensation in an adult patient with isovaleric academia, ” South Med J. 2003 May; 96(5): 500-3. 8. Fries, MH, Rinaldo P, Schmidt-Sommerfeld E, Jurecki E, Packman S. “Isovaleric acidemia: Respons

Gaze-contingent flicker pupil perimetry detects scotomas in patients with cerebral visual impairments or glaucoma

The pupillary light reflex is weaker for stimuli presented inside as compared to outside absolute scotomas. Pupillograph perimetry could thus be an objective measure of impaired visual processing. However, the diagnostic accuracy in detecting scotomas has remained unclear. We quantitatively investigated the accuracy of a novel form of pupil perimetry. The new perimetry method, termed gaze-contingent flicker pupil perimetry, consists of the repetitive on, and off flickering of a bright disk (2 hz; 320 cd/m; 4° diameter) on a gray background (160 cd/m) for 4 seconds per stimulus location. The disk evokes continuous pupil oscillations at the same rate as its flicker frequency, and the oscillatory power of the pupil reflects visual sensitivity. We monocularly presented the disk at a total of 80 locations in the central visual field (max. 15°). The location of the flickering disk moved along with gaze to reduce confounds of eye movements (gaze-contingent paradigm). The test lasted ~5 min per eye and was performed on 7 patients with cerebral visual impairment (CVI), 8 patients with primary open angle glaucoma (age >45), and 14 healthy, age/gender-matched controls. For all patients, pupil oscillation power (FFT based response amplitude to flicker) was significantly weaker when the flickering disk was presented in the impaired as compared to the intact visual field (CVI: 12%, AUC = 0.73; glaucoma: 9%, AUC = 0.63). Differences in power values between impaired and intact visual fields of patients were larger than differences in power values at corresponding locations in the visual fields of the healthy control group (CVI: AUC = 0.95; glaucoma: AUC = 0.87). Pupil sensitivity maps highlighted large field scotomas and indicated the type of visual field defect (VFD) as initially diagnosed with standard automated perimetry (SAP) fairly accurately in CVI patients but less accurately in glaucoma patients. We provide the first quantitative and objective evidence of flicker pupil perimetry's potential in detecting CVI-and glaucoma-induced VFDs. Gaze-contingent flicker pupil perimetry is a useful form of objective perimetry and results suggest it can be used to assess large VFDs with young CVI patients whom are unable to perform SAP

Measurements of flow concentration

In order to identify flaws (porosity-micro delamination) in carbon resin composite materials by ultrasonic testing the amplitudes of the spectrum components of the echographic signal on the transmitted signal are used . The response of the carbon resin complex to an ultrasonic excitation is a sum of ethos due to the reflections at the discontinuities of the propagation medium . Processing of the signal by Fourier analysis enables the type of micro delamination to be identified (square or rectangular) as well as the level of porosity . Two frequency parameters, the band width and the centre frequency of the transfer function seem to give a good indication of the degree ofporosity of the material. This transfer function is calculated using the transmitted signal .Dans le cadre de la caractérisation de défauts (porosites-micro délaminage) dans les matériaux composites carbone-résine par méthode ultrasonore, nous exploitons l'amplitude des composantes spectrales du signal échographique et du signal de double transmission . La réponse d'un complexe carbone-résine à une excitation ultrasonore est une somme d'échos provenant de la réflexion sur les discontinuités du milieu de propagation . Le traitement par analyse de Fourier de ce signal permet de distinguer des formes (carré ou rectangulaire) de micro délaminage ainsi que des taux de porosité . Par ailleurs, deux paramètres fréquentiels : la largeur de la bande et la fréquence centrale de « la fonction de transfert » semblent être un indicateur du taux de porosité . Cette fonction de transfert est calculée à partir des signaux de double transmission

Inhomogeneous magnesium hydride synthesized by low temperature ion implantation: weak localization effect

Metastable MgHx hydride was prepared by H ion implantation into Mg films at 5 K. The resistivity and magnetoresistance temperature dependence reveal weak localization effects due to atomic disorder. At low hydrogen concentrations, x ≤0.3, the conductivity varies as σ∼log (T), typical of two-dimensional weak localization behaviour. The resistivity is also very sensitive to the sample inhomogeneity, due to H diffusion, which can be modelled by introducing a temperature-dependent geometrical percolating factor G. At higher H concentrations, 0.7 ≤x ≤3, after annealing at 20 K, 50 K and 110 K, the samples also exhibit weak localization but with three-dimensional behaviour i.e. a $\sigma \sim \sqrt{T}$. Our analysis is consistent with the existence of an inhomogeneous system formed by a mixture of two phases with contrasted conduction properties, one of which is a well-behaved metal, while the other displays the localization properties. The results lead us to identify the former phase to a non percolating superconducting phase at low temperature

Rejection of randomly coinciding events in Li2_2100^{100}MoO4_4 scintillating bolometers using light detectors based on the Neganov-Luke effect

Random coincidences of nuclear events can be one of the main background sources in low-temperature calorimetric experiments looking for neutrinoless double-beta decay, especially in those searches based on scintillating bolometers embedding the promising double-beta candidate $^{100}$Mo, because of the relatively short half-life of the two-neutrino double-beta decay of this nucleus. We show in this work that randomly coinciding events of the two-neutrino double decay of $^{100}$Mo in enriched Li$_2$$^{100}$MoO$_4$ detectors can be effectively discriminated by pulse-shape analysis in the light channel if the scintillating bolometer is provided with a Neganov-Luke light detector, which can improve the signal-to-noise ratio by a large factor, assumed here at the level of $\sim 750$ on the basis of preliminary experimental results obtained with these devices. The achieved pile-up rejection efficiency results in a very low contribution, of the order of $\sim 6\times10^{-5}$ counts/(keV$\cdot$kg$\cdot$y), to the background counting rate in the region of interest for a large volume ($\sim 90$ cm$^3$) Li$_2$$^{100}$MoO$_4$ detector. This background level is very encouraging in view of a possible use of the Li$_2$$^{100}$MoO$_4$ solution for a bolometric tonne-scale next-generation experiment as that proposed in the CUPID project

Background suppression in massive TeO2_2 bolometers with Neganov-Luke amplified light detectors

Bolometric detectors are excellent devices for the investigation of neutrinoless double-beta decay (0$\nu\beta\beta$). The observation of such decay would demonstrate the violation of lepton number, and at the same time it would necessarily imply that neutrinos have a Majorana character. The sensitivity of cryogenic detectors based on TeO$_2$ is strongly limited by the alpha background in the region of interest for the 0$\nu\beta\beta$ of $^{130}$Te. It has been demonstrated that particle discrimination in TeO$_2$ bolometers is possible measuring the Cherenkov light produced by particle interactions. However an event-by-event discrimination with NTD-based light detectors has to be demonstrated. We will discuss the performance of a highly-sensitive light detector exploiting the Neganov-Luke effect for signal amplification. The detector, being operated with NTD-thermistor and coupled to a 750 g TeO$_2$ crystal, shows the ability for an event-by-event identification of electron/gamma and alpha particles. The extremely low detector baseline noise, RMS 19 eV, demonstrates the possibility to enhance the sensitivity of TeO$_2$-based 0$\nu\beta\beta$ experiment to an unprecedented level

Gap States in Dilute Magnetic Alloy Superconductors

We study states in the superconducting gap induced by magnetic impurities using self-consistent quantum Monte Carlo with maximum entropy and formally exact analytic continuation methods. The magnetic impurity susceptibility has different characteristics for T_{0} \alt T_{c0} and T_{0} \agt T_{c0} ($T_{0}$: Kondo temperature, $T_{c0}$: superconducting transition temperature) due to the crossover between a doublet and a singlet ground state. We systematically study the location and the weight of the gap states and the gap parameter as a function of $T_{0}/T_{c0}$ and the concentration of the impurities.Comment: 4 pages in ReVTeX including 4 encapsulated Postscript figure