MASSACHUSETTS INST OF TECH CAMBRIDGE
Most widely held works by MASSACHUSETTS INST OF TECH CAMBRIDGE
Applications of the Theory of Distributed and Real Time Systems to the Development of Large-Scale Timing Based Systems ( Book )
6 editions published between 1996 and 1998 in English and held by 2 libraries worldwide
We continued our project on the IOA language and toolset, which are designed to support our formal approach to distributed system design and analysis. The design of the IOA language is substantially complete, and appears in a language manual on the web. This quarter, work continued on the development of tools for the IOA language; our toolset will include a parser and static semantic checker, composition routine, support for levels of abstraction interfaces with theorem provers and model checkers, a simulator, and a code generator for real distributed code.
Metabolic Response to Food Restriction in Military-Eligible Women, with a Gender Comparison ( Book )
6 editions published between 1996 and 1999 in English and held by 2 libraries worldwide
Two major series of investigations are being undertaken to explore the metabolic responses of women who meet military standards for body-weight and percent body-fat to the nutritional stressors of food restriction. A comparison of their responses is being made with those occurring in men, who also meet the standards established by the military. The first series (Series 1) has been devoted to the temporal (progressive) changes in lipid, carbohydrate and protein metabolism that occur during a short-term (3 day) fasting period. Data obtained so far for leucine kinetics, nitrogen output, fatty acid kinetics do not reveal any significantly differences, either qualitatively or quantitatively in the metabolic response to an acute total food lack in women versus men. This series of studies will be completed pending further analysis of samples obtained. Work is now underway on the second set of studies. The first phase of this 3-week hypercaloric intake/metabolic study involves the participation of both women and men who receive a hypocaloric diet for 21 days to achieve a 900 Kcal daily dietary deficit that is based on an equal restriction of both lipid and carbohydrate but with keeping protein content at a relatively generous intake of 1.2 g/kg/day. Body composition, metabolic and physical and mental performance changes, are being monitored to asses whether there are gender differences to partial and more prolonged energy restriction.
Role of Ser-Arg Proteins in the Regulation of RNA Processing ( Book )
4 editions published between 1997 and 1998 in English and held by 2 libraries worldwide
Deregulation of alternative splicing has been linked to malignant transformation in breast cancers. Therefore, to fully understand breast cancer, it will be important to identify and characterize factors that regulate the splicing process. We have previously identified a complex of nuclear matrix proteins related to Serine/Arginine- repeat (SR) splicing factors which is required for the splicing of specific pre-niRNAs (Blencowe et al., 1998). This complex contains the SR-matrix proteins of l6OkDa and 3OOkDa (SRml6O and SRm3OO) which, unlike proteins of SR family of splicing factors, lack RNA Recognition Motifs (RRMs). This complex associates with pre-mRNA through multiple interactions involving SR family proteins and small nuclear ribonucleoprotein particles (snRNPs). During the past year, we have completed the sequencing of SRm3OO and have investigated the function of the SRml6O/3OO complex in regulated splicing. We have demonstrated that SRml6O/3OO is required for a purine-rich exonic splicing enhancer (ESE) to promote the splicing of a pre-mRNA containing a weak 3' splice site.
Role of Nuclear Matrix Proteins in the Regulation of Pre-mRNA Splicing ( Book )
3 editions published between 1996 and 1997 in English and held by 2 libraries worldwide
Deregulation of alternative splicing has been linked to malignant transformation in breast cancers. Therefore, to fully understand breast cancer, it will be important to identify and characterize factors that regulate the splicing process. Nuclear matrix proteins (NMp's) containing serine/arginine (SR) rich domains that associate with splicing complexes were isolated and characterized. The NMp's B1C8 (160kDa) and B4Al1 (300kDa) are novel SR phosphoproteins of 820 and 2245 amino acids, respectively. Unlike previously defined SR family proteins (SRp's), which function as constitutive and regulatory splicing factors, B1C8 and B4A11 lack RNA Recognition Motifs (RRMs). B1C8 and B4A11 form a complex (B1C8/B4A11) that associates with SR family proteins SRp40 and SRp75. B1C8/B4A11 is required for the splicing of a subset of pre-mRNAs in vitro. B1C8/B4A11 binds to pre-mRNA and promotes splicing in combination with SR family proteins. The association of B1C8/B4A11 with pre-mRNA also requires binding of U1 snRNP to the 5' splice site and is stabilized by binding of U2 snRNP to the branch site. Thus, B1C8/B4A11 appears to form critical interactions that span intron sequences. These results suggest that B1C8/B4A11 functions as a splicing 'coactivator', by augmenting the activity of factors bound to pre-mRNA. These results are providing new insights into mechanisms by which pre-mRNA splicing may be regulated.
FACTORS AFFECTING DEPTH PERCEPTION ( Book )
2 editions published between 1970 and 1971 in English and held by 2 libraries worldwide
The report describes ongoing work on certain factors that affect depth perception. Research has been directed to a study of the relation between depth and disparity, and to obvious individual differences in these relations. This work has led to the discovery that a sizeable portion of the population is 'stereoblind': many individuals are unable to utilize fully all available disparity cues. The character of these deficits suggests a new basis for depth perception. (Author).
Development of Novel Bifunctional Compounds that Induce Apoptosis in Prostate Cancer Cells ( Book )
6 editions published between 2004 and 2009 in English and held by 1 library worldwide
We have designed and synthesized a novel compound (11beta) that efficiently triggers apoptosis in prostate cancer cells such as LNCaP. This bifunctional compound was designed to form DNA adducts that are camouflaged by the androgen receptor making them less readily repaired in AR+ prostate cancer cells. The aims of our studies are to investigate the mechanisms by which 11 is able to trigger apoptosis in target cells. Methods have been developed that permit us to determine the fates of 11 -DNA adducts in treated cells in culture as well as in tumors growing in animal models. Another objective is to identify the signaling events that lead from DNA adducts to activation of the apoptotic program. Finally we have obtained encouraging results from animal experiments that indicate that molecules such as 11 may have clinical potential for the treatment of human tumors.
Band Structure and Electrical Properties of Amorphous Semiconductors ( Book )
5 editions published between 1970 and 1973 in English and held by 1 library worldwide
Tunneling studies into chalcogenide glasses are reviewed, in order to determine the density of localized states in these materials. Low-temperature (4-77K) switching is investigated in order to determine whether or not trap-filling is a significant feature of the ON-state. The photovoltaic properties of metal-chalcogenide glass junctions is studied. The effects of thermal-neutron irradiation on the physical properties of chalcogenide glasses is investigated in detail. An intensive study of the EPR spectra of memory-type material in both the conducting and non-conducting states is planned. The comparative investigation of crystalline and amorphous Si2Te3 is given. (Author).
Application of weather radar to fallout prediction ( Book )
5 editions published between 1961 and 1962 in English and held by 1 library worldwide
Excellent data were obtained on a variety of weather situations ranging from snowstorms in March to hail and thunderstorms in May. Signal intensity contours on both radars, RHI photographs, R-meter measurements and radiosonde soundings were made. Work was resumed on designing and building a sweep integrater for use with short pulse on the AN/CPS-9 radar. It is probable that frequency modulation rather than amplitude modulation will be employed. A tippingbucket rain gauge was built to operate on the outflow of the Hudson-Jardi gauge and thus monitor its operation. The rainfall data were greatly improved by this addition. The data reduction program and the analysis of storm structure are progressing satisfactorily. The computations on modification of fallout patterns by rain were slowed down by computer and program failures. (Author).
Study of Quantum Mechanical Effects in Deep Submicron, Grating-Gate Field Effect Transistors ( Book )
4 editions published between 1986 and 1991 in English and held by 1 library worldwide
This research program investigates the effect of extreme submicron spatial modulation of the electrostatic potential on the transport in a two-dimensional electron gas (2DEG) in silicon and in III-V compound semiconductor devices. The test vehicle is the so-called grating-gate FET (GGFET). When made to move in a direction perpendicular to the grating gate, electrons experience a surface superlattice (SSL) effect. When moving along the potential modulation electrons are restricted to only one degree of freedom, and thus constitute a quasi-one-dimensional (Q1D) system. Our major achievements in the past year include: In silicon we have fabricated, with high yield, grating gate transistors and measured their current voltage characteristics at liquid helium temperatures. The device mobility at 4 K is about 15000 sq cm/Vs, possibly the highest reported for MOSFETs fabricated using e-beam or x-ray lithographies. Keywords: Surface superlattice, X ray lithography, Deep UV lithography.
Oceanographic Research at M.I.T. in the Department of Earth and Planetary Sciences and the Department of Meteorology ( Book )
4 editions published between 1970 and 1974 in English and held by 1 library worldwide
Contents: Ocean physics; Ocean circulation model studies; Observations of the Equatorial undercurrent in the Indian Ocean; Ocean bottom pressure fluctuations; Mechanics of bottom sediment movement; Marine geochemistry; Marine magnetism; Structural evolution of an oceanic plate; Marine geophysics; Marine gravity.
RESEARCH IN MATERIALS ( Book )
4 editions published between 1969 and 1971 in English and held by 1 library worldwide
This is the eighth in the series of Annual Reports on Research in Materials at the Massachusetts Institute of Technology, issued on behalf of the Institute by the Center for Materials Science and Engineering. The report describes the research conducted at MIT in the field of materials in the academic departments of the Schools of Science and Engineering, the Research Laboratory for Electronics, the National Magnet Laboratory, the Instrumentation Laboratory, and the Lincoln Laboratory. The work in the academic departments and the Research Laboratory of Electronics, Professor H.J. Zimmermann, Director, has been grouped for convenience under the following section headings: Section A - Chemical and Solid State Physics; Section B - Electrical, Magnetic, and Optical Properties of Materials and Application to Devices; Section C - Metallurgy and Materials Science; and Section D - Materials Engineering.
Atmospheric Pressure Gas Lasers ( Book )
4 editions published between 1973 and 1974 in English and held by 1 library worldwide
A single short pulse of width less than the round-trip transit time of a transversely excited laser can be produced by means of simultaneously mode locking and cavity dumping of the laser. Using the above method, single pulses less than 4-nsec wide, with peak power greater than 10 kW have been produced from a TEA CO2 laser. (Author).
Research in materials science and engineering ( Book )
4 editions published between 1965 and 1968 in English and held by 1 library worldwide
This is the sixth in the series of annual reports on research in materials science and engineering at MIT to be issued on behalf of the Institute by the Center for Materials Science and Engineering. The subject matter covered in the report is as follows: chemical and solid state physics; electric, magnetic, and optical properties of materials and applications to devices; metallurgy and material science; and materials engineering.
Application of radar to measurement of surface precipitation ( Book )
4 editions published between 1966 and 1968 in English and held by 1 library worldwide
Work in instrumentation was primarily concerned with installation of new radars and auxiliary equipment. The 10-cm WR-66 radar has an 18-ft parabolic dish which provides high resolution and sensitivity. The signal is averaged by a digital sweep integrator, range-normalized, and quantized into intensity levels which can be displayed on the scope in three shades of gray. A data processor for digital mapping in Cartesian coordinates has been designed. The instruments and techniques which have been developed and are now in operation have overcome many of the limitations in the earlier models. A comprehensive study of mesoscale precipitation patterns and their relation to marcroscale parameters, based on all the storms which occurred during 1962-1963, is in progress. These storms have been grouped according to synoptic type, and analysis of air mass storms and coastal cyclones has been completed. Some preliminary computations have been made on a numerical model for aggregation of snowflakes, a process of importance in the development of raindrop size distributions. (Author).
SOLID-STATE AND MOLECULAR THEORY GROUP ( Book )
47 editions published between 1953 and 1970 in English and held by 1 library worldwide
Contents: Analytic Hartree-Fock wave functions for the 2-P atoms, C.M. Sonnenschein Integrals involving zeta functions, D.E. Ellis Methane, B.J. Woznick The H6 Ring, J.W. Moskowitz Scattering from a diatomic molecule, C.S. Roberts Symmetry properties of the gallium energy bands: the effect of spin orbit interaction, G.F. Koster nergy bands in gallium, J.H. Wood Energy bands in nickel, J.G. Hanus Energy bands in chromium, L.F. Mattheiss Bound states in the spin wave problem, J.G. Hanus The change in the force constants in a molecule or a crystal, R. Englman.
Vortex Simulation of Turbulent Combustion ( Book )
3 editions published between 1990 and 1992 in English and held by 1 library worldwide
This activity focused on the effect of density variation due to temperature/molecular weight difference and/or heat release in a reacting shear layer in two and three dimensional configurations. In the spatially growing 2D layer, results confirm mixing asymmetry due to density difference between the two streams. A light fast stream has a destabilization effect on the early stages of development; it promotes early roll-up; induces stronger winding inside the eddies, and initiates the pairing at earlier stages. However, the overall spatial growth rate of the layer increases as the density ratio becomes higher; bigger eddies are formed and pairing is completed faster. In 3D simulations, density difference continues to impart a convection velocity on the structures in the direction of heavy stream. That influences the evolution of the streamwise mixing modes and spanwise preferential entrainment is observed. 3D reacting shear layer simulations confirmed earlier 2D observations that although the reaction zone structure depends on the Damkohler number, product distribution is independent of the kinetic parameters and exhibit strong resemblance to the vorticity field. (JHD).
Basic Instability Mechanisms in Chemically Reacting Subsonic and Supersonic Flows ( Book )
3 editions published between 1985 and 1987 in English and held by 1 library worldwide
Both theoretical and experimental studies were conducted to determine and elucidate major mechanisms governing turbulence-combustion interactions. The theoretical study showed the importance of wrinkling-like effects as well as the effects of the chemical reaction rate on the evolution of fluctuations in streamwise- and transverse-velocity, temperature, concentration, and vorticity in a shear layer. The wrinkling-like effects were induced by the transverse-velocity fluctuations in nonuniform mean flows. The direct rate-augmentation effects due to reaction led to changes in phase relationships between the various fluctuations, resulting in turbulent energy and mass transport in a direction opposite to that suggested by the gradient model in that part of the shear layer nearer the unreacted region. The experimental study showed the effects of adding ethane (at the same overall equivalence ratio) on the thermal structure of methane/air flames. Temperature fluctuations were augmented by ethane addition, the highest augmentation being observed at 10%-ethane addition. A one-component Laser-Doppler-Velocimetry system was installed and tested.
Oceanographic research at m.i.t. in the department of geology and geophysics and the department of meteorology ( Book )
3 editions published between 1966 and 1969 in English and held by 1 library worldwide
Topics include the following: (1) Heat flow; gravity; magnetics; seismic. (2) magnitude of gravity; vibrating string accelerometer. (3) atmospheric chemistry; sea-air interaction; marine aerosols; trace gaseous constituents. (4) oceanic particulates; light scattering. (5) ocean currents; horizontal velocity; inertial system. (6) ocean currents; neutrally buoyant floats; permanent sound channel. (7) internal waves.
Research on the physical properties of marine soils ( Book )
3 editions published between 1959 and 1962 in English and held by 1 library worldwide
This report describes in detail a method for quantitatively measuring fabric of clay. Wet clay is impregnated with a polyalcohol which permits grinding a very flat surface (without disrupting the original fabric) for quantitative X-ray measurement. In the specific procedure discussed, a Norelco diffractometer equipped with a pole figure device and a Geiger detector was employed to measure by reflection the diffracted intensity of selected peaks (002 and 020) on kaolinite clay. The amplitude of the 002 peak to the amplitude of the 020 peak is called the peak ratio which quantitatively expresses particle orientation on a given surface. Heterogeneity of particle orientation on a surface is expressed in terms of the observed standard deviation relative to the standard deviation expected from counting statistics for peaks of the appropriate amplitude.
Mode of deformation and fracture near the melting point, i - the iron-chromium-nickel ternary system, ii - sub-structure studies, iii ( Book )
3 editions published between 1955 and 1956 in English and held by 1 library worldwide