1,865 research outputs found
Fresh Air Camp Thank You Letter
Form letter from Eartha M.M. White thanking individuals for donations to the Fresh Air Camp. No date given
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The Advanced Photon Source (APS) linear accelerator as a source of slow positrons
The Advanced Photon Source linear accelerator (linac) system consists of a 200-MeV, 2856-MHz S-band electron linac, a 2-radiation-length-thick tungsten target for positron production, and a 450-MeV positron linac. The linac is briefly described, and some possibilities for its use as a slow positron source are discussed
Scaling solutions as Early Dark Energy resolutions to the Hubble tension
A wide class of scalar field models including Quintessence and K-essence have the attractive property of tracker regimes, where the energy density stored in the field evolves so as to mimic that of the dominant background component. During this evolution, for a brief period of time, there is an increase in the energy density of the field as it spirals in towards its attractor solution. We show that when the peak of this energy density occurs around the epoch of equality, we can address a key requirement of early dark energy (EDE), postulated as a solution to the Hubble tension. In particular we demonstrate how this can occur in a wide class of Quintessence, axion and K-essence models, before showing that the Quintessence models suffer in that they generally lead to sound speeds incompatible with the requirements of EDE, whereas the K-essence and axion models can do a better job of fitting the data
Innovative moments and poor outcome in narrative therapy
To analyse a poor outcome case of narrative therapy with a woman victim of intimate violence. Method: The Innovative
Moments Coding System: version 1 was applied to all sessions to track the innovative moments (i-moments) in the therapeutic
process. I moments are the narrative details that occur in psychotherapeutic conversations that are outside the influence of
the problematic narrative. This research aims to describe the processes involved in the stability of meanings in
psychotherapy through a dialogical approach to meaning making. Findings: Contrarily to what usually occurs in good
outcome cases, re-conceptualization i-moments are absent. Moreover, two specific types of i-moments emerged with higher
duration: reflection and protest. Qualitative analysis showed that the potential meanings of these i-moments were surpassed
by a return to the problematic narrative. Conclusion: The therapeutic stability seems to be maintained by a systematic return
to the problematic narrative after the emergence of novelties. This process was referred from a dialogical perspective as a
mutual in-feeding of voices, one that emerges in the i-moment and another one that supports the problematic narrative,
which is maintained by an oscillation between these two types of voices during therapy.This article was supported by the Portuguese Foundation for Science and Technology (FCT), by the Grant PTDC/PSI/72846/2006 (Narrative Processes in Psychotherapy, 2007-2010) and by the PhD Grant SFRH/BD/16995/2004
A method for concentrating lipid peptide DNA and siRNA nanocomplexes that retains their structure and transfection efficiency
Nonviral gene and small interfering RNA (siRNA) delivery formulations are extensively used for biological and therapeutic research in cell culture experiments, but less so in in vivo and clinical research. Difficulties with formulating the nanoparticles for uniformity and stability at concentrations required for in vivo and clinical use are limiting their progression in these areas. Here, we report a simple but effective method of formulating monodisperse nanocomplexes from a ternary formulation of lipids, targeting peptides, and nucleic acids at a low starting concentration of 0.2 mg/mL of DNA, and we then increase their concentration up to 4.5 mg/mL by reverse dialysis against a concentrated polymer solution at room temperature. The nanocomplexes did not aggregate and they had maintained their biophysical properties, but, importantly, they also mediated DNA transfection and siRNA silencing in cultured cells. Moreover, concentrated anionic nanocomplexes administered by convection-enhanced delivery in the striatum showed efficient silencing of the β-secretase gene BACE1. This method of preparing nanocomplexes could probably be used to concentrate other nonviral formulations and may enable more widespread use of nanoparticles in vivo
Block-Spin Approach to Electron Correlations
We consider an expansion of the ground state wavefunction of quantum lattice
many-body systems in a basis whose states are tensor products of block-spin
wavefunctions. We demonstrate by applying the method to the antiferromagnetic
spin-1/2 chain that by selecting the most important many-body states the
technique affords a severe truncation of the Hilbert space while maintaining
high accuracy.Comment: 17 pages, 3 Postscript figure
Sentiment analysis and the impact of employee satisfaction on firm earnings
Prior text mining studies of corporate reputational sentiment based on newswires, blogs and Twitter feeds have mostly captured reputation from the perspective of two groups of stakeholders – the media and consumers. In this study we examine the sentiment of a potentially overlooked stakeholder group, namely, the firm’s employees. First, we present a novel dataset that uses online employee reviews to capture employee satisfaction. We employ LDA to identify salient aspects in employees’ reviews, and manually infer one latent topic that appears to be associated with the firm’s outlook. Second, we create a composite document by aggregating employee reviews for each firm and measure employee sentiment as the polarity of the composite document using the General Inquirer dictionary to count positive and negative terms. Finally, we define employee satisfaction as a weighted combination of the firm outlook topic cluster and employee sentiment. The results of our joint aspect-polarity model suggest that it may be beneficial for investors to incorporate a measure of employee satisfaction into their method for forecasting firm earnings
Tensor network states and geometry
Tensor network states are used to approximate ground states of local
Hamiltonians on a lattice in D spatial dimensions. Different types of tensor
network states can be seen to generate different geometries. Matrix product
states (MPS) in D=1 dimensions, as well as projected entangled pair states
(PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the
lattice model; in contrast, the multi-scale entanglement renormalization ansatz
(MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on
homogeneous tensor networks, where all the tensors in the network are copies of
the same tensor, and argue that certain structural properties of the resulting
many-body states are preconditioned by the geometry of the tensor network and
are therefore largely independent of the choice of variational parameters.
Indeed, the asymptotic decay of correlations in homogeneous MPS and MERA for
D=1 systems is seen to be determined by the structure of geodesics in the
physical and holographic geometries, respectively; whereas the asymptotic
scaling of entanglement entropy is seen to always obey a simple boundary law --
that is, again in the relevant geometry. This geometrical interpretation offers
a simple and unifying framework to understand the structural properties of, and
helps clarify the relation between, different tensor network states. In
addition, it has recently motivated the branching MERA, a generalization of the
MERA capable of reproducing violations of the entropic boundary law in D>1
dimensions.Comment: 18 pages, 18 figure
Upper critical field for underdoped high-T_c superconductors. Pseudogap and stripe--phase
We investigate the upper critical field in a stripe--phase and in the
presence of a phenomenological pseudogap. Our results indicate that the
formation of stripes affects the Landau orbits and results in an enhancement of
. On the other hand, phenomenologically introduced pseudogap leads to a
reduction of the upper critical field. This effect is of particular importance
when the magnitude of the gap is of the order of the superconducting transition
temperature. We have found that a suppression of the upper critical field takes
place also for the gap that originates from the charge--density waves.Comment: 7 pages, 5 figure
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