Unifying metastasis--Integrating intravasation, circulation and end organ colonization

Recent technological advances that have enabled the measurement of circulating tumour cells (CTCs) in patients have spurred interest in the circulatory phase of metastasis. Techniques that do not solely rely on a blood sample allow substantial biological interrogation beyond simply counting CTCs

Quantum signatures of breather-breather interactions

The spectrum of the Quantum Discrete Nonlinear Schr\"odinger equation on a periodic 1D lattice shows some interesting detailed band structure which may be interpreted as the quantum signature of a two-breather interaction in the classical case. We show that this fine structure can be interpreted using degenerate perturbation theory.Comment: 4 pages, 4 fig

Urban wastewater reuse for crop production in the water-short Guanajuato River Basin, Mexico

Water quality / Waste waters / Water reuse / Water resource management / River basins / Irrigation water / Crop production / Water use / Data collection / Case studies / Mexico / Guanajuato River Basin / Tula Irrigation District

Searches for Long-lived Particles at the Tevatron Collider

Several searches for long-lived particles have been performed using data from p-pbar collisions from Run II at the Tevatron. In most cases, new analysis techniques have been developed to carry out each search and/or estimate the backgrounds. These searches expand the discovery potential of the CDF and D0 experiments to new physics that may have been missed by traditional search techniques. This review discusses searches for (1) neutral, long-lived particles decaying to muons, (2) massive, neutral, long-lived particles decaying to a photon and missing energy, (3) stopped gluinos, and (4) charged massive stable particles. It summarizes some of the theoretical and experimental motivations for such searches.Comment: submitted to Mod. Phys. Lett.

Terrestrial Planet Formation I. The Transition from Oligarchic Growth to Chaotic Growth

We use a hybrid, multiannulus, n-body-coagulation code to investigate the growth of km-sized planetesimals at 0.4-2 AU around a solar-type star. After a short runaway growth phase, protoplanets with masses of roughly 10^26 g and larger form throughout the grid. When (i) the mass in these `oligarchs' is roughly comparable to the mass in planetesimals and (ii) the surface density in oligarchs exceeds 2-3 g/sq cm at 1 AU, strong dynamical interactions among oligarchs produce a high merger rate which leads to the formation of several terrestrial planets. In disks with lower surface density, milder interactions produce several lower mass planets. In all disks, the planet formation timescale is roughly 10-100 Myr, similar to estimates derived from the cratering record and radiometric data.Comment: Astronomical Journal, accepted; 22 pages + 15 figures in ps format; eps figures at http://cfa-www.harvard.edu/~kenyon/dl/ revised version clarifies evolution and justifies choice of promotion masse

Super-alfvenic propagation of cosmic rays: The role of streaming modes

Numerous cosmic ray propagation and acceleration problems require knowledge of the propagation speed of relativistic particles through an ambient plasma. Previous calculations indicated that self-generated turbulence scatters relativistic particles and reduces their bulk streaming velocity to the Alfven speed. This result was incorporated into all currently prominent theories of cosmic ray acceleration and propagation. It is demonstrated that super-Alfvenic propagation is indeed possible for a wide range of physical parameters. This fact dramatically affects the predictions of these models

Impact of layer defects in ferroelectric thin films

Based on a modified Ising model in a transverse field we demonstrate that defect layers in ferroelectric thin films, such as layers with impurities, vacancies or dislocations, are able to induce a strong increase or decrease of the polarization depending on the variation of the exchange interaction within the defect layers. A Green's function technique enables us to calculate the polarization, the excitation energy and the critical temperature of the material with structural defects. Numerically we find the polarization as function of temperature, film thickness and the interaction strengths between the layers. The theoretical results are in reasonable accordance to experimental datas of different ferroelectric thin films.Comment: 17 pages, 8 figure

Radio Foregrounds for the 21cm Tomography of the Neutral Intergalactic Medium at High Redshifts

Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature. This so-called 21cm tomography should reveal important information on the physical state of the intergalactic medium at high redshifts. The fluctuations in the redshifted 21 cm, due to gas density inhomogeneities at early times, should be observed at meter wavelengths by the next generation radio telescopes such as the proposed {\it Square Kilometer Array (SKA)}. Here we show that the extra-galactic radio sources provide a serious contamination to the brightness temperature fluctuations expected in the redshifted 21 cm emission from the IGM at high redshifts. Unless the radio source population cuts off at flux levels above the planned sensitivity of SKA, its clustering noise component will dominate the angular fluctuations in the 21 cm signal. The integrated foreground signal is smooth in frequency space and it should nonetheless be possible to identify the sharp spectral feature arising from the non-uniformities in the neutral hydrogen density during the epoch when the first UV sources reionize the intergalactic medium.Comment: 5 pages emulateapj with 1 figure, accepted to Ap

Generational research: between historical and sociological imaginations

This paper reflects on Julia Brannen’s contribution to the development of theory and methods for intergenerational research. The discussion is contextualised within a contemporary ‘turn to time’ within sociology, involving tensions and synergies between sociological and historical imagination. These questions are informed by a juxtaposition of Brannen’s four-generation study of family change and social historian Angela Davis’s exploration women and the family in England between 1945 and 2000. These two studies give rise to complementary findings, yet have distinctive orientations towards the status and treatment of sources, the role of geography in research design and limits of generalisatio