Progressive Neural Networks

Learning to solve complex sequences of tasks--while both leveraging transfer and avoiding catastrophic forgetting--remains a key obstacle to achieving human-level intelligence. The progressive networks approach represents a step forward in this direction: they are immune to forgetting and can leverage prior knowledge via lateral connections to previously learned features. We evaluate this architecture extensively on a wide variety of reinforcement learning tasks (Atari and 3D maze games), and show that it outperforms common baselines based on pretraining and finetuning. Using a novel sensitivity measure, we demonstrate that transfer occurs at both low-level sensory and high-level control layers of the learned policy

Rat Race: Insider Advice on Landing Judicial Clerkships

For many, the judicial clerkship application process is, to quote Sir Winston Churchill, a “riddle wrapped in a mystery inside an enigma.” It is a frenzied “Pamplona-like” atmosphere that begins on Labor Day +1 and continues unabated for several weeks. The initial week is the make or break point in the application review process because it is then that the judge starts to read each application and makes a “yes” or “no” evaluation. If his vote is a “no,” then no further action is taken. If it is a “yes,” the application passes to the law clerks, who then begin their evaluation. Our experience reviewing these applications has led us to the unanimous conclusion that many applicants select their list of judges and put together their packets with little or no thought of strategy as to how to get their applications past this initial phase and into the “yes” pile. We would like to guide the judicial clerkship applicant through the application process by discussing how our chambers conducts the interview and selection process. Specifically, we hope to dispel rumors of what goes on behind the curtain, and ultimately shed some light on how a clerkship applicant could improve his or her chances of receiving an offer. Although this article reflects the viewpoint of only one chambers, our collective experience is broad. Judge Ruggero J. Aldisert has been receiving law clerk applications, interviewing candidates and selecting clerks since 1961. From the standpoint of sheer experience in the law clerk selection process, Judge Aldisert must be near the top of the list of current federal appellate judges. His two present law clerks, Ryan Kirkpatrick and James Stevens, each wear two battle stars for action in the application process. Kirkpatrick and Stevens earned their first star in 2004 when they survived the initial post-Labor Day “running of the bulls,” a term which appropriately describes the federal judiciary’s present hiring plan. The two clerks earned their second star a year later when they closely examined each of the 200 applicants in the 2005 “stampede” and ultimately helped to select the two best candidates to go on to future honors. The authors are fully aware that there is a vast amount of literature discussing the clerkship application process. Most of the literature is couched in somber academic tomes, one of which was serious enough to require 334 footnotes. Our treatment of the subject is far less scholarly. We will not be discussing the role of game theory or the use of the “medical-matching model” in law clerk selection. Our purpose is simply to provide an insider’s perspective into the clerkship application process and, in doing so, defend the following theses: Unless you are the Editor-in-Chief of your school’s main law review or one of the top five or ten students in your class, you need to set yourself apart from the competition. Your road to success is through the face-to-face interview with the Judge. In making this point, we depart from the truism in the decision-making process that writing a good brief is more important than oral argument. In your written applications you may have sterling academic records, stunning extracurricular activities, and superb references, but whether you get the job offer depends on how you perform at the personal interview

Uptake and cytotoxicity of citrate-coated gold nanospheres : comparative studies on human endothelial and epithelial cells

The use of gold nanoparticles (AuNPs) for diagnostic applications and for drug and gene-delivery is currently under intensive investigation. For such applications, biocompatibility and the absence of cytotoxicity of AuNPs is essential. Although generally considered as highly biocompatible, previous in vitro studies have shown that cytotoxicity of AuNPs in certain human epithelial cells was observed. In particular, the degree of purification of AuNPs (presence of sodium citrate residues on the particles) was shown to affect the proliferation and induce cytotoxicity in these cells. To expand these studies, we have examined if the effects are related to nanoparticle size (10, 11 nm, 25 nm), to the presence of sodium citrate on the particles' surface or they are due to a varying degree of internalization of the AuNPs. Since two cell types are present in the major barriers to the outside in the human body, we have also included endothelial cells from the vasculature and blood brain barrier. Results Transmission electron microscopy demonstrates that the internalized gold nanoparticles are located within vesicles. Increased cytotoxicity was observed after exposure to AuNPs and was found to be concentration-dependent. In addition, cell viability and the proliferation of both endothelial cells decreased after exposure to gold nanoparticles, especially at high concentrations. Moreover, in contrast to the size of the particles (10 nm, 11 nm, 25 nm), the presence of sodium citrate on the nanoparticle surface appeared to enhance these effects. The effects on microvascular endothelial cells from blood vessels were slightly enhanced compared to the effects on brain-derived endothelial cells. A quantification of AuNPs within cells by ICP-AES showed that epithelial cells internalized a higher quantity of AuNPs compared to endothelial cells and that the quantity of uptake is not correlated with the amount of sodium citrate on the nanoparticles’ surface. Conclusions In conclusion the higher amount of citrate on the particle surface resulted in a higher impairment of cell viability, but did not enhance or reduce the uptake behavior in endothelial or epithelial cells. In addition, epithelial and endothelial cells exhibited different uptake behaviors for citrate-stabilized gold nanoparticles, which might be related to different interactions occurring at the nanoparticle-cell-surface interface. The different uptake in epithelial cells might explain the higher reduction of proliferation of these cells after exposure to AuNPs treatment although more detailed investigations are necessary to determine subcellular events. Nevertheless an extrinsic effect of sodium-citrate stabilized particles could not be excluded. Thus, the amount of sodium citrate should be reduced to a level on which the stability of the particles and the safety for biomedical applications are guaranteed

A Flaring L5 Dwarf: The Nature of H\alpha Emission in Very Low Mass (Sub)Stellar Objects

Time series spectrophotometry of the L5 dwarf 2MASS 01443536-0716142 showed strong H\alpha emission which declined by nearly 75% in four consecutive exposures. The line was not detected in emission on a spectrum obtained eleven months later. This behavior constrasts with that of 2MASSI J1315309-264951, an L5 dwarf which has shown even stronger H\alpha emission on four separate occasions. The observational database suggests that L dwarfs can be found in such strong flares only occasionally, with a duty cycle of order 1%. In contrast, the few, continuously-strong H\alpha emitters, including PC 0025+0447 and 2MASSI J1237392+652615, must either be (1) objects no older than 10-100 Myrs with continuously-active accretion and/or chromospheres, but which apparently formed in isolation from known young stellar clusters and associations, or (2) objects empowered by a different and unknown mechanism for the H\alpha energy.Comment: 11 pages, 2 figures, Astronomical Journal in press -- Jan 2003 issu

WISEA J114724.10-204021.3: A Free-Floating Planetary Mass Member of the TW Hya Association

We present WISEA J114724.10−204021.3, a young, low-mass, high probability member of the TW Hya association. WISEA J114724.10−204021.3 was discovered based on its red AllWISE color (W1−W2 = 0.63 mag) and extremely red 2MASS J−K_S color (> 2.64 mag), the latter of which is confirmed with near-infrared photometry from the VISTA Hemisphere Survey (J−K_S = 2.57±0.03). Follow-up near-infrared spectroscopy shows a spectral type of L7 ± 1 as well as several spectroscopic indicators of youth. These include a peaked H-band shape and a steeper K-band slope, traits typically attributed to low surface gravity. The sky position, proper motion, and distance estimates of WISEA J114724.10−204021.3 are all consistent with membership in the ∼10 Myr old TW Hya association. Using the age of the TW Hya association and evolutionary models, we estimate the mass of WISEA J114724.10−204021.3 to be 5−13 M_(Jup), making it one of the youngest and lowest mass free-floating objects yet discovered in the Solar neighborhood

Resonance modes in the standard piezoceramic shear geometry: A discussion based on finite element analysis

El pdf del artículo es el manuscrito de autor.Several authors developed methods for the complex characterization of piezoceramics from complex impedance measurements at resonance. Alemany et al. developed an automatic iterative method, applied and reported in a first publication to four modes of resonance: (1) the length extensional mode of a thickness poled rectangular bar; (2) the length extensional mode of long rods or rectangular bars, length poled; (3) the thickness extensional mode of a thin plate and (4) the thickness shear mode of a thin plate. In a second publication it was reported the application of the method to (5) the radial mode of a thin disk, thickness poled, the most mathematically complex geometry. The (2), (3), (4) and (5) modes of resonance are sufficient for the purpose of the determination of the full set of complex elastic, dielectric and piezoelectric coefficients of piezoceramics, a 6mm symmetry material. This work presents the results of the FEA modeling of a thin plate based on the characterization of a commercial ceramic. The comparison of the experimental resonance spectra and the FEA results obtained for elastically, dielectrically and piezoelectrically homogeneous samples is presented and discussed. The complex characterization for the first time of the shear mode of a new lead-free piezoceramic is also shown.This work was carried out under the projects PIRAMID (G5RD-CT-2001-00456) of the GROWTH Program of the EC and MAT 2001-4819-E, MAT2002-00463 and the Ramon y Cajal Program, of the Spanish CICyT, and has benefited from the synergy provided by the POlar ELEtroCERamics, POLECER, (G5RT-CT2001-05024) Thematic Network of the EC.Peer reviewe