Radiatively Induced Type II seesaw and Vector-like 5/3 Charge Quarks

Understanding small neutrino masses in type II seesaw models with TeV scale SM triplet Higgs bosons requires that its coupling with the standard model Higgs doublet H be dialed down to be order eV to KeV, which is a fine-tuning by a factor of $10^{-11}-10^{-8}$ with respect to the weak scale. We present a SUSY extension of the type II seesaw model where this dimensionful small coupling is radiatively induced, thus making its smallness natural. This model has an exotic vector-like quark doublet which contains a quark X with electric charge 5/3 and a top partner t'. We discuss in details the phenomenology of the model paying special attention to the consequences of the interactions of the the exotic heavy quarks and the scalars of the model. Implications for neutrinoless double beta decay and for the LHC experiments are discussed in detail. Remarkably, in this model both the seesaw triplet and the heavy quarks can manifest at colliders in a host of different signatures, including some that significantly differ from those of the minimal models. Depending on the choice of the hierarchy of couplings, the decay of the heavy quarks and of the seesaw triplet may be subject to bounds that can be tighter or looser than the bounds from standard LHC searches. Furthermore we point out a new short-distance contribution to neutrinoless double beta decay mediated by the simultaneous propagation of the type II triplet and exotic fermions. Remarkably this contribution to the neutrinoless double beta decay is parametrically quite independent from the scale of the generated neutrino mass.Comment: 25 pages, 2 figure

New Patterns of Natural R-Parity Violation with Supersymmetric Gauged Flavor

We point out that supersymmetric gauged flavor models provide a realization of R-parity violation (RPV) that is natural in the sense that it does not lead to catastrophic proton decay for natural values of parameters in the theory. Within specific realizations of the idea, the relative strengths of the $\Delta B=1$ $u^c d^c d^c$ type RPV operators can be predicted. In particular, we present examples of gauged flavor models where RPV couplings depend on quark masses as $(m_{u_i} m_{d_j} m_{d_k} / m_t^3)^n$ where $n=1$ or $n= 1/2$. Some phenomenological implications of these models are discussed.Comment: 17 pages, 2 figures, 4 table

Proposals for evaluating the regularity of a scientist'sresearch output

Evaluating the career of individual scientists according to their scientific output is a common bibliometric problem. Two aspects are classically taken into account: overall productivity and overall diffusion/impact, which can be measured by a plethora of indicators that consider publications and/or citations separately or synthesise these two quantities into a single number (e.g. h-index). A secondary aspect, which is sometimes mentioned in the rules of competitive examinations for research position/promotion, is time regularity of one researcher's scientific output. Despite the fact that it is sometimes invoked, a clear definition of regularity is still lacking. We define it as the ability of generating an active and stable research output over time, in terms of both publications/ quantity and citations/diffusion. The goal of this paper is introducing three analysis tools to perform qualitative/quantitative evaluations on the regularity of one scientist's output in a simple and organic way. These tools are respectively (1) the PY/CY diagram, (2) the publication/citation Ferrers diagram and (3) a simplified procedure for comparing the research output of several scientists according to their publication and citation temporal distributions (Borda's ranking). Description of these tools is supported by several examples

Combining Physical galaxy models with radio observations to constrain the SFRs of high-z dusty star forming galaxies

We complement our previous analysis of a sample of z~1-2 luminous and ultra-luminous infrared galaxies ((U)LIRGs), by adding deep VLA radio observations at 1.4 GHz to a large data-set from the far-UV to the sub-mm, including Spitzer and Herschel data. Given the relatively small number of (U)LIRGs in our sample with high S/N radio data, and to extend our study to a different family of galaxies, we also include 6 well sampled near IR-selected BzK galaxies at z~1.5. From our analysis based on the radiative transfer spectral synthesis code GRASIL, we find that, while the IR luminosity may be a biased tracer of the star formation rate (SFR) depending on the age of stars dominating the dust heating, the inclusion of the radio flux offers significantly tighter constraints on SFR. Our predicted SFRs are in good agreement with the estimates based on rest-frame radio luminosity and the Bell (2003) calibration. The extensive spectro-photometric coverage of our sample allows us to set important constraints on the SF history of individual objects. For essentially all galaxies we find evidence for a rather continuous SFR and a peak epoch of SF preceding that of the observation by a few Gyrs. This seems to correspond to a formation redshift of z~5-6. We finally show that our physical analysis may affect the interpretation of the SFR-M* diagram, by possibly shifting, with respect to previous works, the position of the most dust obscured objects to higher M* and lower SFRs.Comment: 26 pages, 15 figures, 3 tables, accepted for publication in MNRAS on Dec. 4th, 201

Optic flow based autopilot: From insects to rotorcraft and back

International audienceWhen insects are flying forwards, the image of the ground sweeps backwards across their ventral viewfield, forming an "optic flow", which depends on both the groundspeed and the height of flight. To explain how these animals manage to avoid the ground using this image motion cue, we suggest that insect navigation hinges on a visual feedback loop we have called the optic flow regulator, which controls the vertical lift. To test this idea, we built a micro-helicopter equipped with a fly-inspired optic flow sensor and an optic flow regulator. We showed that this fly-by-sight microrobot can perform exacting tasks such as takeoff , level flight and landing. Our control scheme accounts for many hitherto unexplained findings published during the last 70 years on insects' visually guided performances, including the facts that honeybees descend under headwind conditions, land with a constant slope and drown when travelling over mirror-smooth water. Our control scheme explains how insects manage to fly safely without any of the instruments used onboard aircraft to measure the height of flight, the airspeed, the groundspeed, and the descent speed. An optic flow regulator could be easily implemented neurally. It is just as appropriate for insects (1) as it would be for aircraft (2,3)

Réguler le flux optique latéral pour naviguer dans un corridor

International audienceAs a first step toward an Automatic Flight Control System (AFCS) for Micro-Air Vehicle (MAV) obstacle avoidance, we introduce a vision based autopilot (LORA: Lateral Optic flow Regulation Autopilot), which is able to make a hovercraft automatically follow a wall or centre between the two walls of a corridor. A hovercraft is endowed with natural stabilization in pitch and roll while keeping two translational degrees of freedom (X and Y) and one rotational degree of freedom (yaw). We show the feasibility of an OF regulator that maintains the lateral Optic Flow (OF) on one wall equal to an OF set-point. The OF sensors used are Elementary Motion Detectors (EMDs), whose working was directly inspired by the housefly motion detecting neurons. The properties of these neurons were previously analysed at our laboratory by performing electrophysiological recordings while applying optical microstimuli to single photoreceptor cells of the compound eye. The simulation results show that depending on the OF set-point, the hovercraft either centres along the midline of the corridor or follows one of the two walls, even with local lack of optical texture on one wall, such as caused, for instance, by an open door or a T-junction. All these navigational tasks are performed with one and the same feedback loop, which consists of a lateral OF regulation loop that permits relatively high-speed navigation (1m/s, i.e 3 body lengths per second), with a minimalist visual system (only two EMDs, each EMD uses two pixels). This principle contrasts with the formerly proposed strategy that consists in equalizing the two lateral OFs. The passive visual sensors and the simple processing system are suitable for use with MAVs with an avionic payload of only a few grams. The goal is to achieve MAV automatic guidance or to relieve a remote operator from guiding it in challenging environments such as urban canyons or indoor environments

The success-index: an alternative approach to the h-index for evaluating an individual's research output

Among the most recent bibliometric indicators for normalizing the differences among fields of science in terms of citation behaviour, Kosmulski (J Informetr 5(3):481-485, 2011) proposed the NSP (number of successful paper) index. According to the authors, NSP deserves much attention for its great simplicity and immediate meaning— equivalent to those of the h-index—while it has the disadvantage of being prone to manipulation and not very efficient in terms of statistical significance. In the first part of the paper, we introduce the success-index, aimed at reducing the NSP-index's limitations, although requiring more computing effort. Next, we present a detailed analysis of the success-index from the point of view of its operational properties and a comparison with the h-index's ones. Particularly interesting is the examination of the success-index scale of measurement, which is much richer than the h-index's. This makes success-index much more versatile for different types of analysis—e.g., (cross-field) comparisons of the scientific output of (1) individual researchers, (2) researchers with different seniority, (3) research institutions of different size, (4) scientific journals, etc

Flying in 3D with an Insect based Visual Autopilot

International audienceFlying insects rely on Optic Flow (OF) cues to avoid collisions, control their speed, control their height, and land. Recent studies have shown that the principle of “OF regulation” may account for various behaviors observed in freely flying insects. The aim of the present study was to suggest a visually guided autopilot enabling an insect to navigate in 3D, and to test its robustness to natural images. Using computer-simulation experiments, we simulated a bee that flies through a tunnel wallpapered with natural images, by controlling both its ground speed and clearance all four sides: the lateral walls, the ground, and the ceiling. The simulated bee can translate along three directions (the surge, sway, and heave axes): it is therefore fully actuated. The new visuo-motor control system, called ALIS (AutopiLot using an Insect based vision System), is a dual OF regulator consisting of two interdependent feedback loops: the speed control loop (along the surge axis) and the positioning control loop (along both the sway and heave axes), each of which has its own OF set-point. The experiments show that the simulated bee navigates safely along a straight tunnel, while compensating for the major OF perturbations caused by, e.g., a tapering of the tunnel or the lack of texture on one wall. The minimalistic visual system used here (only eight pixels) is robust to naturally contrasted stimuli and tunnels, and is sufficient to control both the clearance from the four sides and the forward speed jointly, without requiring to measure any speeds or distances. Besides, the ALIS autopilot accounts remarkably for the quantitative results of ethological experiments performed on honeybees flying freely in straight or tapered corridors

In vitro models of bone-forming tumours: from target to treatment

This thesis describes the generation of cell-of-origin based models, using mesenchymal stem cells, to further elucidate the underlying mechanism of molecular alterations of the bone-forming tumours osteoid osteoma, osteoblastoma and osteosarcoma. Furthermore, we describe the identification of novel treatment options for osteosarcoma using 2D and 3D in vitro models.LUMC / Geneeskund