The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphasis on science and engineering. Its 124-acre primary campus is located approximately 11 mi northeast of downtown Los Angeles.Although founded as a preparatory and vocational school by Amos G. Throop in 1891, the college attracted influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910, and the college assumed its present name in 1921. In 1934, Caltech was elected to the Association of American Universities, and the antecedents of NASA's Jet Propulsion Laboratory, which Caltech continues to manage and operate, were established between 1936 and 1943 under Theodore von Kármán. The university is one among a small group of Institutes of Technology in the United States which tends to be primarily devoted to the instruction of technical arts and applied science.Despite its small size, 33 Caltech alumni and faculty have won a total of 34 Nobel Prizes and 71 have won the United States National Medal of Science or Technology. There are 112 faculty members who have been elected to the National Academies. In addition, numerous faculty members are associated with the Howard Hughes Medical Institute as well as NASA. Caltech managed $332 million in 2011 in sponsored research and $1.85 billion for its endowment in 2013. It also has a long standing rivalry with the Massachusetts Institute of Technology .First year students are required to live on campus, and 95% of undergraduates remain in the on-campus house system. Although Caltech has a strong tradition of practical jokes and pranks, student life is governed by an honor code which allows faculty to assign take-home examinations. The Caltech Beavers compete in 13 intercollegiate sports in the NCAA Division III's Southern California Intercollegiate Athletic Conference. Wikipedia.
California Institute of Technology | Date: 2017-02-22
The invention provides methods and compositions for the expression of small RNA molecules within a cell using a lentiviral vector. The methods can be used to express doubles stranded RNA complexes. Small interfering RNA (siRNA) can be expressed using the methods of the invention within a cell, which are capable of down regulating the expression of a target gene through RNA interference. A variety of cells can be treated according to the methods of the invention including embryos, embryogenic stem cells, allowing for the generation of transgenic animals or animals constituted partly by the transduced cells that have a specific gene or a group of genes down regulated.
California Institute of Technology | Date: 2017-01-11
Technologies are generally described for methods and systems in a machine learning environment. In an example, a method may include receiving training data and test data. The method may also include determining a set of out of sample errors based on the training data and test data. The method may also include determining a set of gradient values based on the out of sample errors. Each gradient value may relate to a first magnitude and to a second magnitude. The first magnitude may be associated with the set of out of sample errors. The second magnitude may be associated with out of sample errors of a portion of the training data excluding a particular point of the test data. The method may also include transforming the set of gradient values into modified density data. The method may also include generating alternative training data based on the modified density data.
Rothenberg E.V.,California Institute of Technology
Annual Review of Immunology | Year: 2014
T and B cells share a common somatic gene rearrangement mechanism for assembling the genes that code for their antigen receptors; they also have developmental pathways with many parallels. Shared usage of basic helix-loop-helix E proteins as transcriptional drivers underlies these common features. However, the transcription factor networks in which these E proteins are embedded are different both in membership and in architecture for T and B cell gene regulatory programs. These differences permit lineage commitment decisions to be made in different hierarchical orders. Furthermore, in contrast to B cell gene networks, the T cell gene network architecture for effector differentiation is sufficiently modular so that E protein inputs can be removed. Complete T cell-like effector differentiation can proceed without T cell receptor rearrangement or selection when E proteins are neutralized, yielding natural killer and other innate lymphoid cells. © 2014 by Annual Reviews. All rights reserved.
Davis M.E.,California Institute of Technology
Chemistry of Materials | Year: 2014
Zeolites and zeolite-like materials are continually finding new applications. Because of the uniformity of these solids, the expression of macroscale materials properties that are controlled by the materials chemistry at the atomic/molecular scale are achievable. In this Perspective, I discuss the following areas of current interest in zeolites and zeolite-like materials that rely on manipulation of the materials chemistry for their preparation and provide new opportunities for application: (i) exploitation of organic structure-directing agents (SDAs) for new materials, (ii) the synthesis of zeolites without SDAs, (iii) the synthesis of very hydrophobic materials, (iv) conversions of two-dimensional (2D) to 3D materials and vice versa, (v) hierarchically organized materials, (vi) chiral materials, and (vii) direction of tetrahedral atoms to specific framework positions. © 2013 American Chemical Society.
Rangel A.,California Institute of Technology
Nature Neuroscience | Year: 2013
To advance our understanding of how the brain makes food decisions, it is essential to combine knowledge from two fields that have not yet been well integrated: the neuro-computational basis of decision-making and the homeostatic regulators of feeding. This Review integrates these two literatures from a neuro-computational perspective, with an emphasis in describing the variables computed by different neural systems and how they affect dietary choice. We highlight what is unique about feeding decisions, the mechanisms through which metabolic and endocrine factors affect the decision-making circuitry, why making healthy food choices is difficult for many people, and key processes at work in the obesity epidemic. © 2013 Nature America, Inc. All rights reserved.
Benson A.J.,California Institute of Technology
Physics Reports | Year: 2010
We review the current theory of how galaxies form within the cosmological framework provided by the cold dark matter paradigm for structure formation. Beginning with the pre-galactic evolution of baryonic material we describe the analytical and numerical understanding of how baryons condense into galaxies, what determines the structure of those galaxies and how internal and external processes (including star formation, merging, active galactic nuclei, etc.) determine their gross properties and evolution. Throughout, we highlight successes and failures of current galaxy formation theory. We include a review of computational implementations of galaxy formation theory and assess their ability to provide reliable modeling of this complex phenomenon. We finish with a discussion of several "hot topics" in contemporary galaxy formation theory and assess future directions for this field. © 2010 Elsevier B.V.
Zmuidzinas J.,California Institute of Technology
Annual Review of Condensed Matter Physics | Year: 2012
Interest in superconducting microresonators has grown dramatically over the past decade. Resonator performance has improved substantially through the use of improved geometries and materials as well as a better understanding of the underlying physics. These advances have led to the adoption of superconducting microresonators in a large number of low-temperature experiments and applications. This review outlines these developments, with particular attention given to the use of superconducting microresonators as detectors. Copyright © 2012 by Annual Reviews. All rights reserved.
Dougherty D.A.,California Institute of Technology
Accounts of Chemical Research | Year: 2013
The chemistry community now recognizes the cation-π interaction as a major force for molecular recognition, joining the hydrophobic effect, the hydrogen bond, and the ion pair in determining macromolecular structure and drug-receptor interactions. This Account provides the author's perspective on the intellectual origins and fundamental nature of the cation-π interaction.Early studies on cyclophanes established that water-soluble, cationic molecules would forego aqueous solvation to enter a hydrophobic cavity if that cavity was lined with π systems. Important gas phase studies established the fundamental nature of the cation-π interaction. The strength of the cation-π interaction (Li+ binds to benzene with 38 kcal/mol of binding energy; NH4 + with 19 kcal/mol) distinguishes it from the weaker polar-π interactions observed in the benzene dimer or water-benzene complexes. In addition to the substantial intrinsic strength of the cation-π interaction in gas phase studies, the cation-π interaction remains energetically significant in aqueous media and under biological conditions. Many studies have shown that cation-π interactions can enhance binding energies by 2-5 kcal/mol, making them competitive with hydrogen bonds and ion pairs in drug-receptor and protein-protein interactions.As with other noncovalent interactions involving aromatic systems, the cation-π interaction includes a substantial electrostatic component. The six (four) C δ--Hδ+ bond dipoles of a molecule like benzene (ethylene) combine to produce a region of negative electrostatic potential on the face of the π system. Simple electrostatics facilitate a natural attraction of cations to the surface. The trend for (gas phase) binding energies is Li+ > Na+ > K+ > Rb+: as the ion gets larger the charge is dispersed over a larger sphere and binding interactions weaken, a classical electrostatic effect. On other hand, polarizability does not define these interactions. Cyclohexane is more polarizable than benzene but a decidedly poorer cation binder.Many studies have documented cation-π interactions in protein structures, where lysine or arginine side chains interact with phenylalanine, tyrosine, or tryptophan. In addition, countless studies have established the importance of the cation-π interaction in a range of biological processes. Our work has focused on molecular neurobiology, and we have shown that neurotransmitters generally use a cation-π interaction to bind to their receptors. We have also shown that many drug-receptor interactions involve cation-π interactions. A cation-π interaction plays a critical role in the binding of nicotine to ACh receptors in the brain, an especially significant case. Other researchers have established important cation-π interactions in the recognition of the "histone code," in terpene biosynthesis, in chemical catalysis, and in many other systems. © 2012 American Chemical Society.
Adhikari R.X.,California Institute of Technology
Reviews of Modern Physics | Year: 2014
Gravitational-wave detection has been pursued relentlessly for over 40 years. With the imminent operation of a new generation of laser interferometers, it is expected that detections will become a common occurrence. The research into more ambitious detectors promises to allow the field to move beyond detection and into the realm of precision science using gravitational radiation. In this article, the state of art for the detectors is reviewed and an outlook for the coming decades is described. © 2014 American Physical Society.
Nakayama Y.,California Institute of Technology
Physics Reports | Year: 2015
In this review article, we discuss the distinction and possible equivalence between scale invariance and conformal invariance in relativistic quantum field theories. Under some technical assumptions, we can prove that scale invariant quantum field theories in d= 2 space-time dimensions necessarily possess the enhanced conformal symmetry. The use of the conformal symmetry is well appreciated in the literature, but the fact that all the scale invariant phenomena in d= 2 space-time dimensions enjoy the conformal property relies on the deep structure of the renormalization group. The outstanding question is whether this feature is specific to d= 2 space-time dimensions or it holds in higher dimensions, too. As of January 2014, our consensus is that there is no known example of scale invariant but non-conformal field theories in d= 4 space-time dimensions under the assumptions of (1) unitarity, (2) Poincaré invariance (causality), (3) discrete spectrum in scaling dimensions, (4) existence of scale current and (5) unbroken scale invariance in the vacuum. We have a perturbative proof of the enhancement of conformal invariance from scale invariance based on the higher dimensional analogue of Zamolodchikov's c-theorem, but the non-perturbative proof is yet to come. As a reference we have tried to collect as many interesting examples of scale invariance in relativistic quantum field theories as possible in this article. We give a complementary holographic argument based on the energy-condition of the gravitational system and the space-time diffeomorphism in order to support the claim of the symmetry enhancement. We believe that the possible enhancement of conformal invariance from scale invariance reveals the sublime nature of the renormalization group and space-time with holography.This review is based on a lecture note on scale invariance vs conformal invariance, on which the author gave lectures at Taiwan Central University for the 5th Taiwan School on Strings and Fields. © 2014 Elsevier B.V.