Mobility Monitoring System For Ecological Studies

Radioactive-nuclide system automatically monitors animals in the field, using radioactive tracers affixed to the animals, Geiger-Muller tube radiation detectors, and event-recorders. Four animals can be monitored simultaneously within a 32-m circle, with each animal as far as 1 m from its associated detector

The bearable compositeness of leptons

Partial compositeness as a theory of flavor in the lepton sector is assessed. We begin presenting the first systematic analysis of neutrino mass generation in this context, and identifying the distinctive mass textures. We then update the bounds from charged lepton flavor and CP violating observables. We put forward a U(1)3 × CP symmetry of the composite sector, in order to allow the new physics to be not far above the TeV scale. This hypothesis effectively suppresses the new contributions to the electron EDM and μ → eγ, by far the most constraining observables, and results in a novel pattern of flavor violation and neutrino masses. The CP violation in the elementary-composite mixing is shown to induce a CKM phase of the correct size, as well as order-one phases in the PMNS matrix. We compare with the alternative possibility of introducing multiple scales of compositeness for leptons, that also allow to evade flavor and CP constraints. Finally, we examine violations of lepton flavor universality in B-meson semi-leptonic decays. The neutral-current anomalies can be accommodated, predicting strong correlations among different lepton flavors, with a few channels close to the experimental sensitivity

Two Higgs doublets to explain the excesses pp→γγ(750 GeV)pp\rightarrow \gamma\gamma(750\ {\rm GeV}) and h→τ±μ∓h \to \tau^\pm \mu^\mp

The two Higgs doublet model emerges as a minimal scenario in which to address, at the same time, the $\gamma\gamma$ excess at 750 GeV and the lepton flavour violating decay into $\tau^\pm \mu^\mp$ of the 125 GeV Higgs boson. The price to pay is additional matter to enhance the $\gamma\gamma$ rate, and a peculiar pattern for the lepton Yukawa couplings. We add TeV scale vector-like fermions and find parameter space consistent with both excesses, as well as with Higgs and electroweak precision observables.Comment: 15 pages, 1 figure; v2: discussion of tau-->mu gamma added, leading to an additional constraint. v3: references added, figure 1 recovered and figure 2 adde

Neutron therapy of cancer

Reports relate applications of neutrons to the problem of cancer therapy. The biochemical and biophysical aspects of fast-neutron therapy, neutron-capture and neutron-conversion therapy with intermediate-range neutrons are presented. Also included is a computer program for neutron-gamma radiobiology

Large neutrino mixing and normal mass hierarchy: a discrete understanding

We discuss the possibility of flavor symmetries to explain the pattern of charged lepton and neutrino masses and mixing angles. We emphasize what are the obstacles for the generation of an almost maximal atmospheric mixing and what are the minimal ingredients to obtain it. A model based on the discrete symmetry $S_3$ is constructed, which leads to the dominant $\mu\tau$-block in the neutrino mass matrix, thus predicting normal hierarchy. This symmetry makes it possible to reproduce current data and predicts $0.01\lesssim\theta_{13}\lesssim 0.03$ and strongly suppressed neutrinoless $2\beta$-decay. Moreover, it implies a relation between lepton and quark mixing angles: $\theta_{23}^q \approx 2(\pi/4-\theta_{23})$. The Cabibbo mixing can also be reproduced and $\theta_{13}^q\sim \theta_{12}^q\theta_{23}^q$. $S_3$ is thus a candidate to describe all the basic features of Standard Model fermion masses and mixing.Comment: 9 pages, revtex, 1 eps figure; clarifications and comments added in sections III.A.1. and III.C.; typos corrected; several references adde

1.55 μm direct bandgap electroluminescence from strained n-Ge quantum wells grown on Si substrates

Electroluminescence from strained n-Ge quantum well light emitting diodes grown on a silicon substrate are demonstrated at room temperature. Electroluminescence characterisation demonstrates two peaks around 1.55 μm and 1.8 μm, which correspond to recombination between the direct and indirect transitions, respectively. The emission wavelength can be tuned by around 4% through changing the current density through the device. The devices have potential applications in the fields of optical interconnects, gas sensing, and healthcare

Dinámica del nitrógeno mineral y la biota edáfica durante la descomposición de enmiendas orgánicas en un ambiente semiárido

El uso de leguminosas como abonos verdes, puede proveer una cantidad importante de nitrógeno para el cultivo posterior, dependiendo de la velocidad de descomposición de los residuos. La necesidad de siembra directa (SD) en los suelos frágiles no permite el enterramiento de los residuos, dificultando su descomposición y la liberación de nitrógeno inorgánico (Ni). En este trabajo se estudió la relación entre descomposición de abonos verdes de vicia con y sin adición de estiércol, la liberación de Ni y la dinámica de las poblaciones microbianas asociadas a estos procesos en el semiárido de la provincia de San Luis, Argentina. En macetas con suelo de la región se incubó suelo solo, dos dosis de vicia y dos dosis de vicia+estiércol durante un año en condiciones reales de temperatura y humedad. Bolsas conteniendo residuos de planta entera de vicia con y sin estiércol fueron ubicadas en superficie (simulando SD) y a 10 cm de profundidad (simulando una labranza mínima) en el suelo de las macetas. Se tomaron muestras de suelo para medir Ni (Nitratos y Amonio) y grupos funcionales microbianos (amonificantes, nitrificantes y celulolíticos). Al mismo tiempo, se retiraron bolsas para medir la velocidad de descomposición del residuo. El contenido de amonio en el suelo aumentó en 6,7 (D1), 28 (D2), 7,3 (D3) y 26 (D4) mg/Kg en un año; por otra parte, el contenido de nitratos aumentó 17 (D1), 32 (D2), 23 (D3) y 41 (D4) mg/Kg. El aumento en el contenido de Ni coincidió con la evolución de las poblaciones de microorganismos amonificantes y nitrificantes. La descomposición en los residuos enterrados (p una importante cantidad de Ni en el primer año (aún en presencia del estiércol que influye en los equilibrios de mineralización inmovilización por su alta relación C/N), pero para su mayor disponibilidad es recomendable realizar una labranza minim

Alexander quandle lower bounds for link genera

We denote by Q_F the family of the Alexander quandle structures supported by finite fields. For every k-component oriented link L, every partition P of L into h:=|P| sublinks, and every labelling z of such a partition by the natural numbers z_1,...,z_n, the number of X-colorings of any diagram of (L,z) is a well-defined invariant of (L,P), of the form q^(a_X(L,P,z)+1) for some natural number a_X(L,P,z). Letting X and z vary in Q_F and among the labellings of P, we define a derived invariant A_Q(L,P)=sup a_X(L,P,z). If P_M is such that |P_M|=k, we show that A_Q(L,P_M) is a lower bound for t(L), where t(L) is the tunnel number of L. If P is a "boundary partition" of L and g(L,P) denotes the infimum among the sums of the genera of a system of disjoint Seifert surfaces for the L_j's, then we show that A_Q(L,P) is at most 2g(L,P)+2k-|P|-1. We set A_Q(L):=A_Q(L,P_m), where |P_m|=1. By elaborating on a suitable version of a result by Inoue, we show that when L=K is a knot then A_Q(K) is bounded above by A(K), where A(K) is the breadth of the Alexander polynomial of K. However, for every g we exhibit examples of genus-g knots having the same Alexander polynomial but different quandle invariants A_Q. Moreover, in such examples A_Q provides sharp lower bounds for the genera of the knots. On the other hand, A_Q(L) can give better lower bounds on the genus than A(L), when L has at least two components. We show that in order to compute A_Q(L) it is enough to consider only colorings with respect to the constant labelling z=1. In the case when L=K is a knot, if either A_Q(K)=A(K) or A_Q(K) provides a sharp lower bound for the knot genus, or if A_Q(K)=1, then A_Q(K) can be realized by means of the proper subfamily of quandles X=(F_p,*), where p varies among the odd prime numbers.Comment: 36 pages; 16 figure

The use of silicon-germanium superlattices for thermoelectric devices and microfabricated generators

Low dimensional structures such as superlattices have the potential to improve the thermoelectric properties of materials by engineering the scattering of phonons to reduce the thermal conductivity and therefore improve the thermeoelectric performance. Here we demonstrate the reduction in thermal conductivity in Ge/SiGe superlattices using multiple barrier engineering to scatter acoustic phonons at the key wavelengths for thermal transport. The approach allows ZT to be increased in wide quantum well superlattices through the reduction of heterointerfaces which scatter both electrons and phonons

The Averaging Method for Asymptotic Evolutions I: Stochastic Differential Equations

Asymptotic evolutions of open systems are studied. Conditions are given under which successive approximate evolutions obtained by the method of averaging are asymptotic to the exact evolution of the open system. It is shown that these conditions are satisfied in the case of stochastic differential equations which describe the evolution of spins in random magnetic fields