The Equivalence Principle in the Non-baryonic Regime

We consider the empirical validity of the equivalence principle for non-baryonic matter. Working in the context of the TH\epsilon\mu formalism, we evaluate the constraints experiments place on parameters associated with violation of the equivalence principle (EVPs) over as wide a sector of the standard model as possible. Specific examples include new parameter constraints which arise from torsion balance experiments, gravitational red shift, variation of the fine structure constant, time-dilation measurements, and matter/antimatter experiments. We find several new bounds on EVPs in the leptonic and kaon sectors.Comment: 22 pages, late

Testing the Equivalence Principle by Lamb shift Energies

The Einstein Equivalence Principle has as one of its implications that the non-gravitational laws of physics are those of special relativity in any local freely-falling frame. We consider possible tests of this hypothesis for systems whose energies are due to radiative corrections, i.e. which arise purely as a consequence of quantum field theoretic loop effects. Specifically, we evaluate the Lamb shift transition (as given by the energy splitting between the $2S_{1/2}$ and $2P_{1/2}$ atomic states) within the context of violations of local position invariance and local Lorentz invariance, as described by the $T H \epsilon\mu$ formalism. We compute the associated red shift and time dilation parameters, and discuss how (high-precision) measurements of these quantities could provide new information on the validity of the equivalence principle.Comment: 40 pages, latex, epsf, 1 figure, final version which appears in Physical Review

From Ideas to Practice, Pilots to Strategy: Practical Solutions and Actionable Insights on How to Do Impact Investing

This report is the second publication in the World Economic Forum's Mainstreaming Impact Investing Initiative. The report takes a deeper look at why and how asset owners began to include impact investing in their portfolios and continue to do so today, and how they overcame operational and cultural constraints affecting capital flow. Given that impact investing expertise is spread among dozens if not hundreds of practitioners and academics, the report is a curation of some -- but certainly not all -- of those leading voices. The 15 articles are meant to provide investors, intermediaries and policy-makers with actionable insights on how to incorporate impact investing into their work.The report's goals are to show how mainstream investors and intermediaries have overcome the challenges in the impact investment sector, and to democratize the insights and expertise for anyone and everyone interested in the field. Divided into four main sections, the report contains lessons learned from practitioner's experience, and showcases best practices, organizational structures and innovative instruments that asset owners, asset managers, financial institutions and impact investors have successfully implemented

Motesanib inhibits Kit mutations associated with gastrointestinal stromal tumors

<p>Abstract</p> <p>Background</p> <p>Activating mutations in Kit receptor tyrosine kinase or the related platelet-derived growth factor receptor (PDGFR) play an important role in the pathogenesis of gastrointestinal stromal tumors (GIST).</p> <p>Methods</p> <p>This study investigated the activity of motesanib, an inhibitor of vascular endothelial growth factor receptors (VEGFR) 1, 2, and 3; PDGFR; and Kit, against primary activating Kit mutants and mutants associated with secondary resistance to imatinib. Single- and double-mutant isoforms of Kit were evaluated for their sensitivity to motesanib or imatinib in autophosphorylation assays and in Ba/F3 cell proliferation assays.</p> <p>Results</p> <p>Motesanib inhibited Kit autophosphorylation in CHO cell lines expressing primary activating mutations in exon 9 (AYins503-504, IC₅₀= 18 nM) and exon 11 (V560 D, IC₅₀= 5 nM; Δ552-559, IC₅₀= 1 nM). Motesanib also demonstrated activity against kinase domain mutations conferring imatinib resistance (V560D/V654A, IC₅₀= 77 nM; V560D/T670I, IC₅₀= 277 nM; Y823 D, IC₅₀= 64 nM) but failed to inhibit the imatinib-resistant D816V mutant (IC₅₀> 3000 nM). Motesanib suppressed the proliferation of Ba/F3 cells expressing Kit mutants with IC₅₀values in good agreement with those observed in the autophosphorylation assays.</p> <p>Conclusions</p> <p>In conclusion, our data suggest that motesanib possesses inhibitory activity against primary Kit mutations and some imatinib-resistant secondary mutations.</p

The extragalactic sub-mm population: predictions for the SCUBA Half-Degree Extragalactic Survey (SHADES)

We present predictions for the angular correlation function and redshift distribution for SHADES, the SCUBA HAlf-Degree Extragalactic Survey, which will yield a sample of around 300 sub-mm sources in the 850 micron waveband in two separate fields. Complete and unbiased photometric redshift information on these sub-mm sources will be derived by combining the SCUBA data with i) deep radio imaging already obtained with the VLA, ii) guaranteed-time Spitzer data at mid-infrared wavelengths, and iii) far-infrared maps to be produced by BLAST, the Balloon-borne Large-Aperture Sub-millimeter Telescope. Predictions for the redshift distribution and clustering properties of the final anticipated SHADES sample have been computed for a wide variety of models, each constrained to fit the observed number counts. Since we are dealing with around 150 sources per field, we use the sky-averaged angular correlation function to produce a more robust fit of a power-law shape w(theta)=(theta/A)^{-delta} to the model data. Comparing the predicted distributions of redshift and of the clustering amplitude A and slope delta, we find that models can be constrained from the combined SHADES data with the expected photometric redshift information.Comment: updated and improved version, accepted for publication in the MNRA

Measuring gravitational waves from binary black hole coalescences: II. the waves' information and its extraction, with and without templates

We discuss the extraction of information from detected binary black hole (BBH) coalescence gravitational waves, focusing on the merger phase that occurs after the gradual inspiral and before the ringdown. Our results are: (1) If numerical relativity simulations have not produced template merger waveforms before BBH detections by LIGO/VIRGO, one can band-pass filter the merger waves. For BBHs smaller than about 40 solar masses detected via their inspiral waves, the band pass filtering signal to noise ratio indicates that the merger waves should typically be just barely visible in the noise for initial and advanced LIGO interferometers. (2) We derive an optimized (maximum likelihood) method for extracting a best-fit merger waveform from the noisy detector output; one "perpendicularly projects" this output onto a function space (specified using wavelets) that incorporates our prior knowledge of the waveforms. An extension of the method allows one to extract the BBH's two independent waveforms from outputs of several interferometers. (3) If numerical relativists produce codes for generating merger templates but running the codes is too expensive to allow an extensive survey of the merger parameter space, then a coarse survey of this parameter space, to determine the ranges of the several key parameters and to explore several qualitative issues which we describe, would be useful for data analysis purposes. (4) A complete set of templates could be used to test the nonlinear dynamics of general relativity and to measure some of the binary parameters. We estimate the number of bits of information obtainable from the merger waves (about 10 to 60 for LIGO/VIRGO, up to 200 for LISA), estimate the information loss due to template numerical errors or sparseness in the template grid, and infer approximate requirements on template accuracy and spacing.Comment: 33 pages, Rextex 3.1 macros, no figures, submitted to Phys Rev

Model-Independent Comparisons of Pulsar Timings to Scalar-Tensor Gravity

Observations of pulsar timing provide strong constraints on scalar-tensor theories of gravity, but these constraints are traditionally quoted as limits on the microscopic parameters (like the Brans-Dicke coupling, for example) that govern the strength of scalar-matter couplings at the particle level in particular models. Here we present fits to timing data for several pulsars directly in terms of the phenomenological couplings (masses, scalar charges, moment of inertia sensitivities and so on) of the stars involved, rather than to the more microscopic parameters of a specific model. For instance, for the double pulsar PSR J0737-3039A/B we find at the 68% confidence level that the masses are bounded by 1.28 < m_A/m_sun < 1.34 and 1.19 < m_B/m_sun < 1.25, while the scalar-charge to mass ratios satisfy |a_A| < 0.21, |a_B| < 0.21 and |a_B - a_A| < 0.002$. These constraints are independent of the details of the scalar tensor model involved, and of assumptions about the stellar equations of state. Our fits can be used to constrain a broad class of scalar tensor theories by computing the fit quantities as functions of the microscopic parameters in any particular model. For the Brans-Dicke and quasi-Brans-Dicke models, the constraints obtained in this manner are consistent with those quoted in the literature.Comment: 19 pages, 7 figure

An NIH intramural percubator as a model of academic-industry partnerships: from the beginning of life through the valley of death

In 2009 the NIH publicly announced five strategic goals for the institutes that included the critical need to translate research discoveries into public benefit at an accelerated pace, with a commitment to find novel ways to engage academic investigators in the process. The emphasis on moving scientific advancements from the laboratory to the clinic is an opportune time to discuss how the NIH intramural program in Bethesda, the largest biomedical research center in the world, can participate in this endeavor. Proposed here for consideration is a percolator-incubator program, a 'percubator' designed to enable NIH intramural investigators to develop new medical interventions as quickly and efficiently as possible

The scientific potential of space-based gravitational wave detectors

The millihertz gravitational wave band can only be accessed with a space-based interferometer, but it is one of the richest in potential sources. Observations in this band have amazing scientific potential. The mergers between massive black holes with mass in the range 10 thousand to 10 million solar masses, which are expected to occur following the mergers of their host galaxies, produce strong millihertz gravitational radiation. Observations of these systems will trace the hierarchical assembly of structure in the Universe in a mass range that is very difficult to probe electromagnetically. Stellar mass compact objects falling into such black holes in the centres of galaxies generate detectable gravitational radiation for several years prior to the final plunge and merger with the central black hole. Measurements of these systems offer an unprecedented opportunity to probe the predictions of general relativity in the strong-field and dynamical regime. Millihertz gravitational waves are also generated by millions of ultra-compact binaries in the Milky Way, providing a new way to probe galactic stellar populations. ESA has recognised this great scientific potential by selecting The Gravitational Universe as its theme for the L3 large satellite mission, scheduled for launch in ~2034. In this article we will review the likely sources for millihertz gravitational wave detectors and describe the wide applications that observations of these sources could have for astrophysics, cosmology and fundamental physics.Comment: 18 pages, 2 figures, contribution to Gravitational Wave Astrophysics, the proceedings of the 2014 Sant Cugat Forum on Astrophysics; v2 includes one additional referenc

Thermodynamic Gravity and the Schrodinger Equation

We adopt a 'thermodynamical' formulation of Mach's principle that the rest mass of a particle in the Universe is a measure of its long-range collective interactions with all other particles inside the horizon. We consider all particles in the Universe as a 'gravitationally entangled' statistical ensemble and apply the approach of classical statistical mechanics to it. It is shown that both the Schrodinger equation and the Planck constant can be derived within this Machian model of the universe. The appearance of probabilities, complex wave functions, and quantization conditions is related to the discreetness and finiteness of the Machian ensemble.Comment: Minor corrections, the version accepted by Int. J. Theor. Phy