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1 Role of Hox genes in mediating the mammalian body planThis is a 1 hour, 5 minutes, 28 seconds video of a lecture given by Mario Capecchi on the genetic analysis of the Hox complex, or Hox cluster and their role in embryogenesis. Using examples such as the development of the hindbrain (rhombencephalon), facial nerves, and hands Capecchi outlines the re...Transgenic mice; Gene targeting; Genetic engineering; Molecular genetics; Homeobox genes; Histology - Pathological; Gene expression; Gene regulation; Genotype; Phenotype
2 Secret of life module: on the brink, four profiles in groundbreaking scienceThis is a 15 minutes, 12 seconds segment of the WGBH series, Secret of life. Profiles include Dennis Slamon of UCLA and his work on the oncagenes and the creation of excess receptors that play a significant role in breast cancer; Patricia Steeg of the National Cancer Institute (NCI) and her work on...Transgenic mice; Gene targeting; Genetic engineering; Molecular genetics; Cancer - Research; Capecchi, Mario R.; Science - Moral and ethical aspects; Human chromosome abnormalities - Diagnosis; Gene expression; Gene regulation
3 Divergence, convergence, and the ancestry of feral populations in the domestic rock pigeonStringham, Sydney A.; Mulroy, Elisabeth E.; Xing, Jinchuan; Record, David; Guernsey, Michael W.; Aldenhoven, Jaclyn T.; Osborne, Edward J.
4 Divergence, convergence, and the ancestry of feral populations in the domestic rock pigeonStringham, Sydney A.; Mulroy, Elisabeth E.; Xing, Jinchuan; Record, David; Guernsey, Michael W.; Aldenhoven, Jaclyn T.; Osborne, Edward J.
5 Phonon free path in an isotopic mixtureA time-dependent perturbation theory is developed for the classical laws of motion of a crystal lattice. This is applied to the case of a cubic crystal which is chemically pure but contains various isotopic constituents. The random variations in the masses of neighboring atoms scatter plane wave p...Crystal lattice; Thermal conductivity1957-05
6 Theory of the anomalous skin effect in normal and superconducting metalsChambers' expression for the current density in a normal metal in which the electric field varies over a mean free path is derived from a quantum approach in which use is made of the density matrix in the presence of scattering centers but in the absence of the field. An approximate expression use...Skin effect1958-07
7 Anomalous skin effect in a magnetic fieldA classical and quantum mechanical derivation of cyclotron resonance in metals is given. The classical result differs slightly from that obtained by Azbel and Kaner. The quantum derivation yields the same result as the classical calculation except that in the limit of low quantum numbers or high m...Cyclotron resonance; Skin effect; Quantum transport1958-07
8 Theory of negative-mass cyclotron resonanceIn recent communications1'2 Dousmanis et al. suggest that the re-entrant energy contours of the heavy-hole bands in Ge and Si3 could contribute a negative resistivity component to the overall resistivity of these materials, possibly related to a nonequilibrium density of carriers in these re-ent...Cyclotron resonance; Steady state1959-07
9 Steady-state distribution function in dilute electron gasesIt is usually assumed that optically created carriers in a photoconductor rapidly thermalize to a Boltzmann distribution, regardless of the generation and recombination mechanisms. However, it can be shown that this distribution which is characteristic of thermodynamic equilibrium is incompatible w...Photoconductors; Thermal scattering; Steady state; Cyclotron resonance1960-10
10 Exact wave functions in superconductivityThe ground-state wave function and some of the excited states of the BCS reduced Hamiltonian are found. In the limit of large volume, the boundary and continuity conditions on the exact wave function lead directly to the equations which Bardeen, Cooper, and Schrieffer found by a variational techniqu...Ground states1961
11 Ordering energy levels of interacting spin systemsThe total spin S is a good quantum number in problems of interacting spins. We have shown that for rather general antiferromagnetic or ferrimagnetic Hamiltonians, which need not exhibit translational invariance, the lowest energy eigenvalue for each value of S [denoted E(S) ] is ordered in a natural...Interacting spin; Energy levels; Ferrimagnetic arrays1962
12 Theory of ferromagnetism and the ordering of electronic energy levelsConsider a system of N electrons in one dimension subject to an arbitrary symmetric potential, V(xi,…,xN), and let E(S) be the lowest energy belonging to the total spin value S. We have proved the following theorem: E(S) 1962-01
13 Role of Fermi surface and crystal structure in theory of magnetic metalsWe have investigated the magnetic ground state of metals using an idealized theory of magnetism based on the Ruderman-Kittel-Yosida indirect exchange interaction. The preliminary, but suggestive, results reported here are for simple cubic structures and spherical Fermi surface. We find that as the...Magnetic metals; Crystal structure1962-11
14 Theory of magnetothermomechanicsWe show that in both ferromagnetic and antiferromagnetic systems with weak magnetostrictive coupling the coefficient of thermal expansion gives a useful measure of the magnetic specific heat. We also analyze the strong coupling situation by means of our simplified, but soluble model, and find it pos...Magnetothermomechanics; Magnetostriction1963-01
15 Ground state of interacting spinsThe question is posed of how the ground state of the Heisenberg Hamiltonian H= - ΣFij Si-Sj depends on the magnitude s of N interacting spins, particularly in the case of long-ranged oscillatory interactions Fij. It is discussed whether fixing the geometry and the bond strengths Fij suffices to d...Ground states; Interacting spin; Ruderman-Kittel interaction1963-04
16 Thermal screening effects in a ferromagnetIn considering the theory of spin waves,1 we have examined elementary excitations of the Hamiltonian and lowest-order interactions among these excitations, in cases when j(Rij) is a very long-ranged, oscillatory interaction.2 As numerical computation is required, we are preparing to program the I...Ferromagnet; Thermal screening1963-06
17 Ferromagnetism and spin waves in the band theoryIntra-atomic exchange (Hund's rule mechanism) and Heisenberg nearest-neighbor exchange are examined for their role in the ferromagnetism of metals with degenerate bands. We examine the ground state, and find there is ferromagnetism once the largest eigenvalue j00 of the exchange matrix exceeds 1/2...Band theory; Hund's rule1963-12
18 Low-field relaxation and the study of ultraslow atomic motions by magnetic resonanceConventional resonance enables one to study motion of atoms by measurement of line width when the mean time r between jumps is less than 1/Aco, where Aa> is the rigid lattice line width, or by measurement of the spin-lattice relaxation time, Ti, when r ^ l / coo , where coo is the Larmor frequency. ...Ultraslow atomic motion; Magnetic resonance1964
19 Band theory of ferromagnetism, antiferromagnetism, and spin wavesIntra-atomic exchange (Hund's rule mechanism) and Heisenberg nearest-neighbor exchange are examined for their role in the ferromagnetism of metals with degenerate bands. The equations of motion of spin waves valid near T=0°K are derived, and a number of branches are found. When the equations are ...Orbital degeneracy; Indirect exchange theory; Band theory1964
20 Study of utraslow atomic motions by magnetic resonanceMagnetic resonance has been widely used to study phenomena such as atomic diffusion and molecular reorientation. It is applicable when the mean time, r, between atomic jumps is either (a) sufficiently short to narrow the resonance line width or (b) of the correct magnitude to produce spin-lattice ...Atomic motion; Magnetic resonance; Ultraslow atomic motion1964
21 Long-ranged magnetic polarization effectsTwo years ago a group1 at Bell Telephone Laboratories discovered an exceedingly long-ranged magnetic interaction among rare earth (RE) atoms dissolved in palladium. It is the purpose of the present note to suggest a theory for this phenomenon, which, it will be recalled, could not be explained by t...Indirect exchange theory1964-05
22 Exact solution of a many-fermion system and its associated boson fieldLuttinger's exactly soluble model of a one-dimensional many-fermion system is discussed. We show that he did not solve his model properly because of the paradoxical fact that the density operator commutators [p(p), p(-p')], which always vanish for any finite number of particles, no longer vanish in ...Many-electron problem; Fermi surface; Boson field; Dirac sea1965
23 Observation of ultraslow translational diffusion in metallic lithium by magnetic resonanceThe theory of a new magnetic-resonance technique for studying the ultra slow motion of atoms was presented in a previous paper. In this paper, we present its experimental confirmation for the case of translational diffusion in lithium metal. By this technique the mean time between atomic jumps r can...Ultraslow atomic motion; Magnetic resonance1965
24 Localized magnetic moments in dilute metallic alloys: correlation effectsWe discuss qualitatively the importance of the correlation energy in determining the ground state of a metal with an impurity atom. For a single, partly occupied impurity Estate orbital, the correlation energy acts to prevent the appearance of a nonvanishing ground-state spin, so that this simple no...Magnetic moments; Metallic alloys; Correlation energy; Magnetic impurities; Orbital degeneracy1965-11
25 Using fissionAtoms are just like people, both are lazy. Energy is a measure of work, i.e., more work implies more energy. Atoms do not like to work, hence they try to reduce the energy in their atomic system. For different elements the energy reduction occurs by reaction, e.g., an energetic sodium atom reacts w...Uranium-235; Uranium-2381966
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