Kerr metric in Bondi-Sachs form
Bishop, Nigel T.; Venter, Liebrecht R.
2006-04-15
A metric representing the Kerr geometry has been obtained by Pretorius and Israel. We make coordinate transformations on this metric, to bring it into Bondi-Sachs form. We investigate the behavior of the metric near the axis of symmetry and confirm elementary flatness, and we also confirm that it is asymptotic to the Bondi-Sachs form of the Schwarzschild geometry. The results obtained here are needed so that numerical relativity codes based on the characteristic formalism can be applied to a situation that contains a rotating black hole.
Diagnosis and molecular characterization of non-classic forms of Tay-Sachs disease in Brazil.
Rozenberg, R; Kok, F; Burin, M G; Sá Miranda, M C; Vasques, C; Henriques-Souza, A M M; Giugliani, R; Vainzof, Mariz; Pereira, L V
2006-06-01
Molecular analysis of five Brazilian families, including eight patients presenting with nonclassic Tay-Sachs disease, was performed to identify frequent causative mutations and their correlation with clinical course. Three patients were affected by the B1 subacute variant and were shown to carry the R178H mutation (the DN allele), which is also common among Portuguese patients. Two of them were compound heterozygotes, whereas the third presented with the mutation in both alleles. Since Brazil was a Portuguese colony for over two centuries, common ancestry might be the probable explanation. The fourth patient presented with a juvenile phenotype and carries the R499H mutation, which has been reported only once worldwide and is associated with residual enzyme activity, responsible for a slower clinical course. The fifth family, of an Ashkenazi Jewish background, showed an extensive intrafamilial clinical variability among three affected sibs presenting with muscle atrophy, ataxia, and psychiatric symptoms. They were first diagnosed as having atypical spinal muscular atrophy and, subsequently, spinocerebellar ataxia, but, recently, the diagnosis of late-onset Tay-Sachs disease was confirmed based on reduced plasma hexosaminidase A activity and the G269S/InsTATC1278 genotype. It is therefore highly recommended to test patients with a similar clinical history for Tay-Sachs disease. In the same family, one first cousin committed suicide at the age of 24 years, presenting with a clinical phenotype that suggested an undiagnosed case and highlighting the effect of the intrafamilial clinical variability in delaying a prompt diagnosis. It is now recognized that his parents are, in fact, a carrier couple. Additionally, another relative had been previously identified as a heterozygote in a Tay-Sachs disease screening program, but the information was not shared among the family. Since this information might anticipate diagnosis and genetic counseling, it is advisable that
Resources - Tay-Sachs ... The following organizations provide information on Tay-Sachs disease : March of Dimes -- www.marchofdimes.com/pnhec/4439_1227.asp National Tay-Sachs and Allied Diseases Association -- www.ntsad.org
... this page: //medlineplus.gov/ency/article/001417.htm Tay-Sachs disease To use the sharing features on this page, please enable JavaScript. Tay-Sachs disease is a life-threatening disease of the ...
Tay-Sachs disease is a rare, inherited disorder. It causes too much of a fatty substance to build up in the ... mental and physical problems. Infants with Tay-Sachs disease appear to develop normally for the first few ...
Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards
2003-07-22
We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.
Electromagnetic nucleon form factors
Bender, A.; Roberts, C.D.; Frank, M.R.
1995-08-01
The Dyson-Schwinger equation framework is employed to obtain expressions for the electromagnetic nucleon form factor. In generalized impulse approximation the form factor depends on the dressed quark propagator, the dressed quark-photon vertex, which is crucial to ensuring current conservation, and the nucleon Faddeev amplitude. The approach manifestly incorporates the large space-like-q{sup 2} renormalization group properties of QCD and allows a realistic extrapolation to small space-like-q{sup 2}. This extrapolation allows one to relate experimental data to the form of the quark-quark interaction at small space-like-q{sup 2}, which is presently unknown. The approach provides a means of unifying, within a single framework, the treatment of the perturbative and nonperturbative regimes of QCD. The wealth of experimental nucleon form factor data, over a large range of q{sup 2}, ensures that this application will provide an excellent environment to test, improve and extend our approach.
Inelastic Scattering Form Factors
Energy Science and Technology Software Center (ESTSC)
1992-01-01
ATHENA-IV computes form factors for inelastic scattering calculations, using single-particle wave functions that are eigenstates of motion in either a Woods-Saxon potential well or a harmonic oscillator well. Two-body forces of Gauss, Coulomb, Yukawa, and a sum of cut-off Yukawa radial dependences are available.
Nucleon Electromagnetic Form Factors
Kees de Jager
2004-08-01
Although nucleons account for nearly all the visible mass in the universe, they have a complicated structure that is still incompletely understood. The first indication that nucleons have an internal structure, was the measurement of the proton magnetic moment by Frisch and Stern (1933) which revealed a large deviation from the value expected for a point-like Dirac particle. The investigation of the spatial structure of the nucleon, resulting in the first quantitative measurement of the proton charge radius, was initiated by the HEPL (Stanford) experiments in the 1950s, for which Hofstadter was awarded the 1961 Nobel prize. The first indication of a non-zero neutron charge distribution was obtained by scattering thermal neutrons off atomic electrons. The recent revival of its experimental study through the operational implementation of novel instrumentation has instigated a strong theoretical interest. Nucleon electro-magnetic form factors (EMFFs) are optimally studied through the exchange of a virtual photon, in elastic electron-nucleon scattering. The momentum transferred to the nucleon by the virtual photon can be selected to probe different scales of the nucleon, from integral properties such as the charge radius to scaling properties of its internal constituents. Polarization instrumentation, polarized beams and targets, and the measurement of the polarization of the recoiling nucleon have been essential in the accurate separation of the charge and magnetic form factors and in studies of the elusive neutron charge form factor.
Electromagnetic pion form factor
Roberts, C.D.
1995-08-01
A phenomenological Dyson-Schwinger/Bethe-Salpeter equation approach to QCD, formalized in terms of a QCD-based model field theory, the Global Color-symmetry Model (GCM), was used to calculate the generalized impulse approximation contribution to the electromagnetic pion form factor at space-like q{sup 2} on the domain [0,10] GeV{sup 2}. In effective field theories this form factor is sometimes understood as simply being due to Vector Meson Dominance (VMD) but this does not allow for a simple connection with QCD where the VMD contribution is of higher order than that of the quark core. In the GCM the pion is treated as a composite bound state of a confined quark and antiquark interacting via the exchange of colored vector-bosons. A direct study of the quark core contribution is made, using a quark propagator that manifests the large space-like-q{sup 2} properties of QCD, parameterizes the infrared behavior and incorporates confinement. It is shown that the few parameters which characterize the infrared form of the quark propagator may be chosen so as to yield excellent agreement with the available data. In doing this one directly relates experimental observables to properties of QCD at small space-like-q{sup 2}. The incorporation of confinement eliminates endpoint and pinch singularities in the calculation of F{sub {pi}}(q{sup 2}). With asymptotic freedom manifest in the dressed quark propagator the calculation yields q{sup 4}F{sub {pi}}(q{sup 2}) = constant, up to [q{sup 2}]- corrections, for space-like-q{sup 2} {approx_gt} 35 GeV{sup 2}, which indicates that soft, nonperturbative contributions dominate the form factor at presently accessible q{sup 2}. This means that the often-used factorization Ansatz fails in this exclusive process. A paper describing this work was submitted for publication. In addition, these results formed the basis for an invited presentation at a workshop on chiral dynamics and will be published in the proceedings.
D. Day
2007-03-01
The nucleon form factors are still the subject of active investigation even after an experimental effort spanning 50 years. This is because they are of critical importance to our understanding of the electromagnetic properties of nuclei and provide a unique testing ground for QCD motivated models of nucleon structure. Progress in polarized beams, polarized targets and recoil polarimetry have allowed an important and precise set of data to be collected over the last decade. I will review the experimental status of elastic electron scattering from the nucleon along with an outlook for future progress.
Ryong Ji, C.; Pang, A.; Szczepaniak, A.
1994-04-01
It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.
Nucleon Electromagnetic Form Factors
Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi
2007-10-01
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.
Venus - Sag Caldera 'Sachs Patera
NASA Technical Reports Server (NTRS)
1991-01-01
This image of Sachs Patera on Venus is centered at 49 degrees north, 334 degrees east. Defined as a sag-caldera, Sachs is an elliptical depression 130 meters (81 feet) in depth, spanning 40 kilometers (25 miles) in width along its longest axis. The morphology implies that a chamber of molten material drained and collapsed, forming a depression surrounded by concentric scarps spaced 2-to-5 kilometers (1.2- to-3 miles) apart. The arc-shaped set of scarps, extending out to the north from the prominent ellipse, is evidence for a separate episode of withdrawal; the small lobe-shaped extension to the southwest may represent an additional event. Solidified lava flows 10-to-25 kilometers (6-to-16 miles) long, give the caldera its flower-like appearance. The flows are a lighter tone of gray in the radar data because the lava is blockier in texture and consequently returns more radar waves. Much of the lava, which was evacuated from the chamber, probably traveled to other locations underground, while some of it may have surfaced further south. This is unlike calderas on Earth, where a rim of lava builds up in the immediate vicinity of the caldera.
Hou, Y.; Vavougios, G.; Hinek, A.
1996-07-01
Substitution mutations adversely affecting the {alpha}-subunit of {beta}-hexosaminidase A ({alpha}{beta}) (EC 3.2.1.52) result in Tay-Sachs disease. The majority affect the initial folding of the pro-{alpha} chain in the endoplasmic reticulum, resulting in its retention and degradation. A much less common occurrence is a mutation that specifically affects an {open_quotes}active-site{close_quotes} residue necessary for substrate binding and/or catalysis. In this case, hexosaminidase A is present in the lysosome, but it lacks all {alpha}-specific activity. This biochemical phenotype is referred to as the {open_quotes}B1-variant form{close_quotes} of Tay-Sachs disease. Kinetic analysis of suspected B1-variant mutations is complex because hexosaminidase A is heterodimeric and both subunits possess similar active sites. In this report, we examine a previously identified B1-variant mutation, {alpha}-Val{sup 192}Leu. Chinese hamster ovary cells were permanently cotransfected with an {alpha}-cDNA-construct encoding the substitution and a mutant {beta}-cDNA ({beta}-Arg{sup 211}Lys), encoding a {beta}-subunit that is inactive but normal in all other respects. We were surprised to find that the Val{sup 192}Leu substitution produced a pro-{alpha} chain that did not form {alpha}-{beta} dimers and was not transported to the lysosome. Finally, we reexamined the hexosaminidase activity and protein levels in the fibroblasts from the original patient. These data were also not consistent with the biochemical phenotype of the B1 variant of Tay-Sachs disease previously reported to be present. Thus, we conclude that the Val{sup 192}Leu substitution does not specifically affect the {alpha}-active site. 23 refs., 4 figs., 2 tabs.
Dru Renner
2012-04-01
Precision computation of hadronic physics with lattice QCD is becoming feasible. The last decade has seen precent-level calculations of many simple properties of mesons, and the last few years have seen calculations of baryon masses, including the nucleon mass, accurate to a few percent. As computational power increases and algorithms advance, the precise calculation of a variety of more demanding hadronic properties will become realistic. With this in mind, I discuss the current lattice QCD calculations of generalized parton distributions with an emphasis on the prospects for well-controlled calculations for these observables as well. I will do this by way of several examples: the pion and nucleon form factors and moments of the nucleon parton and generalized-parton distributions.
The neutron electric form factor to Q² = 1.45 (GeV/c)²
Bradley Plaster
2004-02-01
The nucleon elastic electromagnetic form factors are fundamental quantities needed for an understanding of nucleon and nuclear electromagnetic structure. The evolution of the Sachs electric and magnetic form factors with Q2, the square of the four-momentum transfer, is related to the distribution of charge and magnetization within the nucleon. High precision measurements of the nucleon form factors are essential for stringent tests of our current theoretical understanding of confinement within the nucleon. Measurements of the neutron form factors, in particular, those of the neutron electric form factor, have been notoriously difficult due to the lack of a free neutron target and the vanishing integral charge of the neutron. Indeed, a precise measurement of the neutron electric form factor has eluded experimentalists for decades; however, with the advent of high duty-factor polarized electron beam facilities, experiments employing polarization degrees of freedom have finally yielded the first precise measurements of this fundamental quantity. Following a general overview of the experimental and theoretical status of the nucleon form factors, a detailed description of an experiment designed to extract the neutron electric form factor from measurements of the neutron's recoil polarization in quasielastic 2H(e, e')1H scattering is presented. The experiment described here employed the Thomas Jefferson National Accelerator Facility's longitudinally polarized electron beam, a magnetic spectrometer for detection of the scattered electron, and a neutron polarimeter designed specifically for this experiment. Measurements were conducted at three Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2, and the final results extracted from an analysis of the data acquired in this experiment are reported and compared with recent theoretical predictions for the nucleon form factors.
Well-posed ADM equivalent of the Bondi-Sachs problem
Frittelli, Simonetta
2006-06-15
Every well-posed hyperbolic problem has an associated characteristic representation. In the case of the Einstein equations, traditionally, characteristic problems have been stated in the Bondi-Sachs form, whereas initial-value problems have been represented in the ADM form, both being looked upon as independent versions of the Einstein equations. Under the restriction of spherical symmetry, we provide an ADM version of the Einstein equations that functions as the initial-value representation of the Bondi-Sachs equations. The ADM version allows us to interpret the Bondi-Sachs variables precisely in terms of characteristic fields of the Cauchy problem. The Bondi-Sachs version thus leads us to a version of the Cauchy problem that is first order in time (with no need for reduction) and automatically well posed.
Analytic parametrization for nuclear form factors
Atkin, G.; Dumbrajs, O.
1982-08-01
A new analytic parametrization of the nuclear form factor is developed using a factorization theorem. We show that the nuclear form factor can be represented in terms of its real zeros and its asymptotic behavior. The parametrization is applied to nuclear form factor data of /sup 3/He and /sup 4/He. Our results suggest that further diffraction minima can be expected at higher momentum transfer where experiments have not yet been made.
On form factors of boundary changing operators
NASA Astrophysics Data System (ADS)
Bajnok, Z.; Hollo, L.
2016-04-01
We develop a form factor bootstrap program to determine the matrix elements of local, boundary condition changing operators. We propose axioms for these form factors and determine their solutions in the free boson and Lee-Yang models. The sudden change in the boundary condition, caused by an operator insertion, can be interpreted as a local quench and the form factors provide the overlap of any state before the quench with any outgoing state after the quench.
Nucleon Form Factors from Generalized Parton Distributions
M. Guidal; Maxim Polyakov; Anatoly Radyushkin; Marc Vanderhaeghen
2004-10-01
We discuss the links between Generalized Parton Distributions (GPDs) and elastic nucleon form factors. These links, in the form of sum rules, represent powerful constraints on parametrizations of GPDs. A Regge parametrization for GPDs at small momentum transfer, is extended to the large momentum transfer region and it is found to describe the basic features of proton and neutron electromagnetic form factor data. This parametrization is used to estimate the quark contribution to the nucleon spin.
Form factor and boundary contribution of amplitude
NASA Astrophysics Data System (ADS)
Huang, Rijun; Jin, Qingjun; Feng, Bo
2016-06-01
The boundary contribution of an amplitude in the BCFW recursion relation can be considered as a form factor involving boundary operator and unshifted particles. At the tree-level, we show that by suitable construction of Lagrangian, one can relate the leading order term of boundary operators to some composite operators of mathcal{N} = 4 superYang-Mills theory, then the computation of form factors is translated to the computation of amplitudes. We compute the form factors of these composite operators through the computation of corresponding double trace amplitudes.
Testing Gravity Against Early Time Integrated Sachs-Wolfe Effect
Zhang, Pengjie; /Shanghai, Astron. Observ. /Fermilab
2005-11-01
A generic prediction of general relativity is that the cosmological linear density growth factor D is scale independent. But in general, modified gravities do not preserve this signature. A scale dependent D can cause time variation in gravitational potential at high redshifts and provides a new cosmological test of gravity, through early time integrated Sachs-Wolfe (ISW) effect-large scale structure (LSS) cross correlation. We demonstrate the power of this test for a class of f(R) gravity, with the form f(R) = {lambda}{sub 1}H{sub 0}{sup 2} exp(-R/{lambda}{sub 2}H{sub 0}{sup 2}). Such f(R) gravity, even with degenerate expansion history to {Lambda}CDM, can produce detectable ISW effect at z {approx}> 3 and l {approx}> 20. Null-detection of such effect would constrain {lambda}{sub 2} to be {lambda}{sub 2} > 1000 at > 95% confidence level. On the other hand, robust detection of ISW-LSS cross correlation at high z will severely challenge general relativity.
Proton form factor effects in hydrogenic atoms
Daza, F. Garcia; Kelkar, N. G.; Nowakowski, M.
2011-10-21
The proton structure corrections to the hyperfine splittings in electronic and muonic hydrogen are evaluated using the Breit potential with electromagnetic form factors. In contrast to other methods, the Breit equation with q{sup 2} dependent form factors is just an extension of the standard Breit equation which gives the hyperfine splitting Hamiltonian. Precise QED corrections are comparable to the structure corrections which therefore need to be evaluated ab initio.
Nucleon and Δ electromagnetic form factors
NASA Astrophysics Data System (ADS)
Bartoš, Erik; Dubnička, Stanislav; Dubničková, Anna-Zuzana
2015-11-01
The unitary and analytic model for nucleons works very well. The model for spin 1 2+ baryons can predict static parameters for Λ, Σ+, Σ0, Σ-, Ξ, Ξ-. We prepared the scheme how to construct the model also for Δ nucleon resonance. It was used to describe transition form factor GM∗ and the experimentally measured ratio RSM with the help of relations for magnetic dipole transition and charge quadrupole form factors.
Magnetic form factors of the trinucleons
Schiavilla, R; Pandharipande, V R; Riska, Dan-Olof
1989-11-01
The magnetic form factors of ^{3}H and ^{3}He are calculated with the Monte Carlo method from variational ground-state wave functions obtained for the Argonne and Urbana two- and three-nucleon interactions. The electromagnetic current operator contains one- and two-body terms that are constructed so as to satisfy the continuity equation with the two-nucleon potential in the Hamiltonian. The results obtained with the Argonne two-nucleon interaction are in overall agreement with the empirical values. It appears that the remaining theoretical uncertainty, in the calculation of these form factors from a given interaction model, is dominated by that in the electromagnetic form factors of the nucleon. It is found that the isovector magnetic form factors are rather sensitive to the details of the isospin-dependent tensor force, and they are much better reproduced with the Argonne than the Urbana potential. The isoscalar magnetic form factors appear to be sensitive to the spin-orbit interactions, and are better reproduced with the Urbana potential. The Argonne potential has a stronger τ1∙τ2 tensor force, while the Urbana one has a shorter-range spin-orbit interaction.
The Form Factors of the Nucleons
Perdrisat, Charles F.
2013-11-01
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has been greatly improved by performing double-polarization experiments, in comparison with with pre-vious unpolarized cross section data. Here we will review the experimental data base in view of the new results for the proton and the neutron, obtained at MIT-Bates, JLab and MAMI. The rapid evolution of phenomenological models triggered by these high- precision experiments will be discussed. In particular, the possibility that the proton is non-spherical in its ground state, and that the transverse charge density are model in- dependently defined in the infinite momentum frame. Likewise, flavor decomposition of the nucleon form factors into dressed u and d quark form factors, may give information about the quark-diquark structure of the nucleon. The current proton radius "crisis" will also be discussed.
Charm form factors in hadronic interactions
Bracco, M. E.; Navarra, F. S.; Nielsen, M.; Chiapparini, M.
2010-12-28
We calculate the form factors and the coupling constants in vertices with charm mesons, such as {rho}D*D*, in the framework of QCD sum rules. We first discuss the applications of these form factors in heavy ion collisions and in B decays. We then present an introduction to the method of QCD sum rules and describe how to work with the three-point function. We give special attention to the procedure employed to extrapolate results obtained in the deep euclidean region to the poles of the particles, located in the time-like region. Finally we present a table of ready-to-use parametrizations of all the form factors, which are relevant for the processes mentioned in the introduction. We also give the coupling constants.
Nucleon Form Factors - A Jefferson Lab Perspective
John Arrington, Kees de Jager, Charles F. Perdrisat
2011-06-01
The charge and magnetization distributions of the proton and neutron are encoded in their elastic electromagnetic form factors, which can be measured in elastic electron--nucleon scattering. By measuring the form factors, we probe the spatial distribution of the proton charge and magnetization, providing the most direct connection to the spatial distribution of quarks inside the proton. For decades, the form factors were probed through measurements of unpolarized elastic electron scattering, but by the 1980s, progress slowed dramatically due to the intrinsic limitations of the unpolarized measurements. Early measurements at several laboratories demonstrated the feasibility and power of measurements using polarization degrees of freedom to probe the spatial structure of the nucleon. A program of polarization measurements at Jefferson Lab led to a renaissance in the field of study, and significant new insight into the structure of matter.
Hadronic form factors in kaon photoproduction
Syukurilla, L. Mart, T.
2014-09-25
We have revisited the effect of hadronic form factors in kaon photoproduction process by utilizing an isobaric model developed for kaon photoproduction off the proton. The model is able to reproduce the available experimental data nicely as well as to reveal the origin of the second peak in the total cross section, which was the main source of confusion for decades. Different from our previous study, in the present work we explore the possibility of using different hadronic form factors in each of the KΛN vertices. The use of different hadronic form factors, e.g. dipole, Gaussian, and generalized dipole, has been found to produce a more flexible isobar model, which can provide a significant improvement in the model.
Electromagnetic charged and neutral kaon form factors
Roberts, C.D.; Burden, C.J.; Thomson, M.J.
1995-08-01
The electromagnetic form factor of the charged and neutral kaon is calculated using the approach applied in the successful study of the pion form factor, described above. The charged kaon form factor will be measured in forthcoming experiments at CEBAF. Our calculation involves the dressed strange quark propagator, to which F{sub {pi}}(q{sup 2}) is not sensitive, and hence it provides us with constraints on the strange-quark sector of QCD. Our preliminary results are encouraging. We find that the strange and up/down quark propagators are not too different, once the change in the current-quark-mass is accounted for. However, the difference that remains is important since it allows {l_angle}{bar s}s{r_angle}<{l_angle}{bar u}u{r_angle}. This calculation is the first to yield a value of f{sub K}/f{sub {pi}} that is in good agreement with experiment and also yields r{sub K+}/r{sub {pi}} in good agreement with experiment. Our calculated charged kaon form factor provides a prediction that will be tested in the forthcoming CEBAF experiments. Our studies also show that K{sup 0} has a negative charge radius, as is to be expected. Our calculated value will be compared with that measured in K{sub s}{sup 0} regeneration from electrons.
Meson-photon transition form factors
Balakireva, Irina; Lucha, Wolfgang; Melikhov, Dmitri
2012-10-23
We present the results of our recent analysis of the meson-photon transition form factors F{sub P{gamma}}(Q{sup 2}) for the pseudoscalar mesons P {pi}{sup 0},{eta},{eta} Prime ,{eta}{sub c}, using the local-duality version of QCD sum rules.
Form Factors and Radii of Light Nuclei
Sick, Ingo
2015-09-15
We discuss the determination of electromagnetic form factors from the world data on electron–nucleus scattering for nuclei Z ≤ 3, with particular emphasis on the derivation of the moments required for comparison with measurements from electronic/muonic atoms and isotope shifts.
Form Factors and Radii of Light Nuclei
NASA Astrophysics Data System (ADS)
Sick, Ingo
2015-09-01
We discuss the determination of electromagnetic form factors from the world data on electron-nucleus scattering for nuclei Z ≤ 3, with particular emphasis on the derivation of the moments required for comparison with measurements from electronic/muonic atoms and isotope shifts.
Nucleon and Elastic and Transition Form Factors
NASA Astrophysics Data System (ADS)
Segovia, Jorge; Cloët, Ian C.; Roberts, Craig D.; Schmidt, Sebastian M.
2014-12-01
We present a unified study of nucleon and elastic and transition form factors, and compare predictions made using a framework built upon a Faddeev equation kernel and interaction vertices that possess QCD-like momentum dependence with results obtained using a symmetry-preserving treatment of a vector vector contact-interaction. The comparison emphasises that experiments are sensitive to the momentum dependence of the running couplings and masses in the strong interaction sector of the Standard Model and highlights that the key to describing hadron properties is a veracious expression of dynamical chiral symmetry breaking in the bound-state problem. Amongst the results we describe, the following are of particular interest: possesses a zero at Q 2 = 9.5 GeV2; any change in the interaction which shifts a zero in the proton ratio to larger Q 2 relocates a zero in to smaller Q 2; there is likely a value of momentum transfer above which ; and the presence of strong diquark correlations within the nucleon is sufficient to understand empirical extractions of the flavour-separated form factors. Regarding the -baryon, we find that, inter alia: the electric monopole form factor exhibits a zero; the electric quadrupole form factor is negative, large in magnitude, and sensitive to the nature and strength of correlations in the Faddeev amplitude; and the magnetic octupole form factor is negative so long as rest-frame P- and D-wave correlations are included. In connection with the transition, the momentum-dependence of the magnetic transition form factor, , matches that of once the momentum transfer is high enough to pierce the meson-cloud; and the electric quadrupole ratio is a keen measure of diquark and orbital angular momentum correlations, the zero in which is obscured by meson-cloud effects on the domain currently accessible to experiment. Importantly, within each framework, identical propagators and vertices are sufficient to describe all properties discussed herein. Our
[Tay-Sachs disease in non-Jewish infant in Israel].
Nadim, Nasser
2012-01-01
Tay-Sachs disease, also known as GM2 gangliosidosis or Hexosaminidase A deficiency is an autosomal recessive genetic fatal disorder. The disease is known to appear in East European Ashkenazi Jews, North African Jews, and Quebec French Canadians exclusively, but, with different frequency and type of mutation. Its most common variant is the infantile type Tay-Sachs disease. Juvenile and late-onset forms of the disease are infrequent and slowly progressive. At nearly 3 to 6 months old, a baby with Tay-Sachs progressively loses his motor skills and attentiveness. Startle responses and hyperreflexia become prominent, especially on eliciting deep patellar and Achilles reflexes, as a consequence of neurodegeneration of the upper motor neuron. Other systemic damage ensues gradually; seizures, blindness, spasticity of limbs, inability to swallow and breathe, and eventually the baby dies at 1-4 years of age. All Tay-Sachs patients have a "cherry red spot", easily seen in the macula area of the retina, using an ophthalmoscope. The "cherry red spot" is the only normal part of the retina in these sick babies. The case presented here emphasizes that Tay-Sachs disease is sometimes misdiagnosed at first visits even by an experienced clinician, because of his lack of awareness that this disease is not exclusively a Jewish disease. PMID:22670494
Kantowski-Sachs cosmological solutions in the generalized teleparallel gravity via Noether symmetry
NASA Astrophysics Data System (ADS)
Motavalli, H.; Akbarieh, A. Rezaei; Nasiry, M.
2016-04-01
We study the f(T) theory as an extension of teleparallel gravity and consider the Noether symmetry of Kantowski-Sachs (KS) anisotropic model for this theory. We specify the explicit teleparallel form of f(T) and find the corresponding exact cosmological solutions under the assumption that the Lagrangian admits the Noether symmetry. It is found that the universe experiences a power law expansion for the scale factors in the context of f(T) theory. By deriving equation of state (EOS) parameter, we show that the universe passes through the phantom and ΛCDM theoretical scenarios. In this way, we estimate a lower limit age for the universe in excellent agreement with the value reported from recent observations. When KS model reduces to the flat Friedmann-Robertson-Walker (FRW) metric, our results are properly transformed into the corresponding values.
Burg-Metzner-Sachs symmetry, string theory, and soft theorems
NASA Astrophysics Data System (ADS)
Avery, Steven G.; Schwab, Burkhard U. W.
2016-01-01
We study the action of the Burg-Metzner-Sachs (BMS) group in critical, bosonic string theory living on a target space of the form Md×C . Here Md is d -dimensional (asymptotically) flat spacetime and C is an arbitrary compactification. We provide a treatment of generalized Ward-Takahashi identities and derive consistent boundary conditions for any d from string theory considerations. Finally, we derive BMS transformations in higher-dimensional spacetimes and show that the generalized Ward-Takahashi identity of BMS produces Weinberg's soft theorem in string theory.
Tay-Sachs disease: a case report.
Arisoy, A E; Ozden, S; Ciliv, G; Ozalp, I
1995-01-01
Tay-Sachs disease (GM2 gangliosidosis I) is an autosomal recessive lysosomal-storage disorder confined to the central nervous system, resulting from deficiency of hexosaminidase A. The case presented is of a twelve-month-old girl brought to the hospital because of mental-motor deterioration and convulsions. She was the child of first cousins and had a history of the deaths of two siblings with the same manifestations. Generalized hypotonia, macrocephaly, hyperacusis and a retinal cherry red spot appearance were present. There was no organomegaly. The diagnosis of Tay-Sachs disease was made by means of absence of serum hexosaminidase A activity. PMID:7732608
Brown, C.A.; Mahuran, D.J. )
1993-08-01
In vitro mutagenesis and transient expression in COS cells has been used to associate a missense mutation with a clinical or biochemical phenotype. Mutations affecting the [alpha]-subunit of [beta]-hexosaminidase A ([alpha][beta]) (E.C.3.2.1.52) result in Tay-Sachs disease. Because hexosaminidase A is heterodimeric, analysis of [alpha]-chain mutations is not straightforward. The authors examine three approaches utilizing previously identified mutations affecting [alpha]-chain folding. These involve transfection of (1) the [alpha] cDNA alone; (2) a [beta] cDNA construct encoding a [beta]-subunit substituted at a position homologous to that of the [alpha]-subunit, and (3) both [alpha] and [beta] cDNAs. The latter two procedures amplified residual activity levels over that of patient samples, an effect not previously found with mutations affecting an [open quotes]active[close quotes] [alpha]Arg residue. This effect may help to discriminate between protein-folding and active-site mutations. The authors conclude that, with proper controls, the latter method of cotransfection can be used to evaluate the effects and perhaps to predict the clinical course of some [alpha]-chain mutations. Using this technique, they demonstrate that the adult-onset Tay-Sachs mutation, [alpha]Gly[yields]Ser[sup 269], does not directly affect [alpha][beta] dimerization but exerts an indirect effect on the dimer through destabilizing the folded [alpha]-subunit at physiological temperatures. Two other [alpha] mutations linked to more severe phenotypes appear to inhibit the initial folding of the subunit. 36 refs., 2 figs., 5 tabs.
Unified description of kaon electroweak form factors
A. Afanasev; W. Buck
1996-06-01
A calculation of the semileptonic decays of the kaon (K{sub l3}) is presented. The results are direct predictions of a covariant model of the pion and kaon introduced earlier by Ito, Buck, Gross. The weak form factors for K{sub l3} are predicted with absolutely no parameter adjustments of the model. The authors obtained for the form factor parameters: f{sub {minus}}(q{sup 2}=m{sub l}{sup 2})/f{sub +}(q{sup 2}=m{sub l}{sup 2})={minus}0.28 and {lambda}{sub +}= 0.028, both within experimental error bars. Connections of this approach to heavy quark symmetry will also be discussed.
Nucleon form factor studies at Jlab
Giusa, A; Mammoliti, F; Russo, G; Sperduto, M L; Sutera, C M; Cisbani, E; Garibaldi, F; Urciuoli, G M; Capogni, M; Cates, G D; de Jager, K; Wojtsekhowski, B
2011-08-01
The ratio of the electromagnetic proton elastic form factors, GpE/GpM, has been measured at Jefferson Lab up to View the MathML source, by using the CEBAF 6 GeV electron beam, and revealing an unexpected and challenging physical behaviour. The 2014 scheduled 12 GeV upgrade will allow the measurement of GpE/GpM up to View the MathML source, by taking advantage of the new large-acceptance forward spectrometer Super BigBite (SBS) in Hall A. Measurements of neutron form factors in the region around 10 (GeV/c)2, where quark confinement plays an important role, are expected to show the behaviour already observed in the proton case.
Elastic form factors at higher CEBAF energies
Petratos, G.G.
1994-04-01
The prospects for elastic scattering from few body systems with higher beam energies at CEBAF is presented. The deuteron and{sup 3}He elastic structure functions A(Q{sup 2}) can be measured at sufficiently high momentum transfers to study the transition between the conventional meson-nucleon and the constituent quark-gluon descriptions. Possible improvements in the proton magnetic form factor data are also presented.
Heavy to light baryon transition form factors
Guo, X. |; Huang, T. |; Li, Z.
1996-05-01
Recently, Stech found form factor relations for heavy to light transitions based on two simple dynamical assumptions for a spectator particle. In this paper we generalize his approach to the case of baryons and find that for {Lambda}{sub {ital Q}}{r_arrow}{Lambda} ({ital Q}={ital b} or {ital c}) only one independent form factor remains in the limit {ital m}{sub {ital Q}}{r_arrow}{infinity}. Furthermore, combining with the model of Guo and Kroll we determine both of the two form factors for {Lambda}{sub {ital Q}}{r_arrow}{Lambda} in the heavy quark limit. The results are applied to {Lambda}{sub {ital b}}{r_arrow}{Lambda}+{ital J}/{psi} which is not clarified both theoretically and experimentally. It is found that the branching ratio of {Lambda}{sub {ital b}}{r_arrow}{Lambda}+{ital J}/{psi} is of order 10{sup {minus}5}. {copyright} {ital 1996 The American Physical Society.}
Electric Form Factor of the Neutron
Feuerbach, Robert
2007-10-13
Recent polarization-based precision measurements of the nucleons' elastic electric form factors have led to surprising results. The measurement of the ratio of the proton's electromagnetic form factors, $\\mu_p G_E^p/G_M^p$, was found to drop nearly linearly with $Q^2$ out to at least $5 \\mathrm{GeV}^2$, inconsistent with the older Rosenbluth-type experiments. A recent measurement of $G_E^n$, the neutron's electric form-factor saw $G_E^n$ does not fall off as quickly as commonly expected up to $Q^2 \\approx 1.5 \\mathrm{GeV}^2$. Extending this study, a precision measurement of $G_E^n$ up to $Q^2=3.5 \\mathrm{GeV}^2$ was completed in Hall A at Jefferson Lab. The ratio $G_E^n/G_M^n$ was measured through the beam-target asymmetry $A_\\perp$ of electrons quasi-elastically scattered off polarized neutrons in the reaction ${}^{3}\\overrightarrow{He}(\\overrightarrow{e},e' n)$. The experiment took full advantage of the electron beam, recent target developments, as well as two detectors new to Jefferson Lab. The measurement used the accelerator's 100\\% duty-cycle high-polarization (typically 84\\%) electron beam and a new, hybrid optically-pumped polarized ${}^{3}\\overrightarrow{He}$ target which achieved in-beam polarizations in excess of 50\\%. A medium acceptance (80msr) open-geometry magnetic spectrometer (BigBite) detected the scattered electron, while a geometrically matched neutron detector observed the struck neutron. Preliminary results from this measurement will be discussed and compared to modern calculations of $G_E^n$.
Nucleon Form Factors Using Spin Degrees of Freedom
Mark Jones
2002-04-01
An overview of recent measurements of the neutron and proton electromagnetic form factors from double polarization experiments. Spin observables are sensitive to the product of nucleon form factor which allows access to the small nucleon electric form factors.
Survey of nucleon electromagnetic form factors
Perdrisat, Charles F.; Punjabi, Vina A.
2011-09-20
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has been greatly improved by performing double polarization experiments, in compar- ison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at MIT-Bates, MAMI, and JLab. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed.
Pion form factor from a contact interaction
Gutierrez-Guerrero, L. X.; Bashir, A.; Cloeet, I. C.; Roberts, C. D.
2010-06-15
In a Poincare-covariant vector-boson-exchange theory, the pion possesses components of pseudovector origin, which materially influence its observable properties. For a range of such quantities, we explore the consequences of a momentum-independent interaction, regularized in a symmetry-preserving manner. The contact interaction, while capable of describing pion static properties, produces a form factor whose evolution for Q{sup 2}>0.17 GeV{sup 2} disagrees markedly with experiment and whose asymptotic power-law behavior conflicts strongly with perturbative QCD.
Pion form factor from a contact interaction.
Gutierrez-Guerrero, L. X.; Bashir, A.; Cloet, I. C.; Roberts, C. D.
2010-01-01
In a Poincare-covariant vector-boson-exchange theory, the pion possesses components of pseudovector origin, which materially influence its observable properties. For a range of such quantities, we explore the consequences of a momentum-independent interaction, regularized in a symmetry-preserving manner. The contact interaction, while capable of describing pion static properties, produces a form factor whose evolution for Q{sup 2} > 0.17 GeV{sup 2} disagrees markedly with experiment and whose asymptotic power-law behavior conflicts strongly with perturbative QCD.
Rapid identification of HEXA mutations in Tay-Sachs patients.
Giraud, Carole; Dussau, Jeanne; Azouguene, Emilie; Feillet, François; Puech, Jean-Philippe; Caillaud, Catherine
2010-02-19
Tay-Sachs disease (TSD) is a recessively inherited neurodegenerative disorder due to mutations in the HEXA gene resulting in a beta-hexosaminidase A (Hex A) deficiency. The purpose of this study was to characterize the molecular abnormalities in patients with infantile or later-onset forms of the disease. The complete sequencing of the 14 exons and flanking regions of the HEXA gene was performed with a unique technical condition in 10 unrelated TSD patients. Eleven mutations were identified, including five splice mutations, one insertion, two deletions and three single-base substitutions. Four mutations were novel: two splice mutations (IVS8+5G>A, IVS2+4delAGTA), one missense mutation in exon 6 (c.621T>G (p.D207E)) and one small deletion (c.1211-1212delTG) in exon 11 resulting in a premature stop codon at residue 429. The c.621T>G missense mutation was found in a patient presenting an infantile form. Its putative role in the pathogenesis of TSD is suspected as residue 207 is highly conserved in human, mouse and rat. Moreover, structural modelling predicted changes likely to affect substrate binding and catalytic activity of the enzyme. The time-saving procedure reported here could be useful for the characterization of Tay-Sachs-causing mutations, in particular in non-Ashkenazi patients mainly exhibiting rare mutations. PMID:20100466
Electromagnetic Transition Form Factors of Nucleon Resonances
Burkert, Volker D.
2008-10-13
Recent measurements of nucleon resonance transition form factors with CLAS at Jefferson Lab are discussed. The new data resolve a long-standing puzzle of the nature of the Roper resonance, and confirm the assertion of the symmetric constituent quark model of the Roper as the first radial excitation of the nucleon. The data on high Q{sup 2} n{pi}{sup +} production confirm the slow fall off of the S{sub 11}(1535) transition form factor with Q{sup 2}, and better constrain the branching ratios {beta}{sub N{pi}} = 0.50 and {beta}{sub N{eta}} = 0.45. For the first time, the longitudinal transition amplitude to the S{sub 11}(1535) was extracted from the n{pi}{sup +} data. Also, new results on the transition amplitudes for the D{sub 13}(1520) resonance are presented showing a rapid transition from helicity 3/2 dominance seen at the real photon point to helicty 1/2 dominance at higher Q{sup 2}.
Helium Compton Form Factor Measurements at CLAS
Voutier, Eric J.-M.
2013-07-01
The distribution of the parton content of nuclei, as encoded via the generalized parton distributions (GPDs), can be accessed via the deeply virtual Compton scattering (DVCS) process contributing to the cross section for leptoproduction of real photons. Similarly to the scattering of light by a material, DVCS provides information about the dynamics and the spatial structure of hadrons. The sensitivity of this process to the lepton beam polarization allows to single-out the DVCS amplitude in terms of Compton form factors that contain GPDs information. The beam spin asymmetry of the $^4$He($\\vec {\\mathrm e}$,e$' \\gamma ^4$He) process was measured in the experimental Hall B of the Jefferson Laboratory to extract the real and imaginary parts of the twist-2 Compton form factor of the $^4$He nucleus. The experimental results reported here demonstrate the relevance of this method for such a goal, and suggest the dominance of the Bethe-Heitler amplitude to the unpolarized process in the kinematic range explored by the experiment.
75 FR 44031 - Goldman, Sachs & Co., et al.; Notice of Application and Temporary Order
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... COMMISSION Goldman, Sachs & Co., et al.; Notice of Application and Temporary Order July 21, 2010. AGENCY... injunction entered against Goldman, Sachs & Co. (``Goldman Sachs'') on July 20, 2010 by the United States.... Applicants: Goldman Sachs, Goldman Sachs Asset Management, L.P. (``GSAM, L.P.''), Goldman......
Chiral corrections to hyperon vector form factors
NASA Astrophysics Data System (ADS)
Anderson, Jeffrey; Luty, Markus A.
1993-06-01
We show that the leading chiral corrections to the ΔS=1 f1 vector form factors of hyperons are O(ms) and O(m3/2s), and are expected to be ~20-30 % by dimensional analysis. This is consistent with the Ademollo-Gatto theorem. We compute the O(ms) corrections and a subset of the O(m3/2s) corrections using an effective Lagrangian in which the baryons are treated as heavy particles. All of these corrections are surprisingly small, ~5% combining them, we obtain ~5-10 % corrections. The pattern of corrections is very different from that predicted by quark models.
Elastic and Transition Form Factors in DSEs
NASA Astrophysics Data System (ADS)
Segovia, Jorge
2016-06-01
A symmetry preserving framework for the study of continuum quantum chromodynamics (QCD) is obtained from a truncated solution of the QCD equations of motion or QCD's Dyson-Schwinger equations (DSEs). A nonperturbative solution of the DSEs enables the study of, e.g., hadrons as composites of dressed-quarks and dressed-gluons, the phenomena of confinement and dynamical chiral symmetry breaking, and therefrom an articulation of any connection between them. It is within this context that we present a unified study of Nucleon, Delta and Roper elastic and transition form factors, and compare predictions made using a framework built upon a Faddeev equation kernel and interaction vertices that possess QCD-like momentum dependence with results obtained using a symmetry-preserving treatment of a vector ⊗ vector contact-interaction.
Nucleon Transition Form Factors and New Perspectives
Gothe, R W
2007-10-01
The status of the electro-excitation program to study baryon resonances at Jefferson Lab will be exemplified by the most recent results on resonance parameters and transition form factors in single and double-pion production. These results demonstrate that the separation of resonance and background contributions and therefore the extraction of the electro-coupling amplitudes of resonances become easier and cleaner at higher four-momentum transfers (Q2). Furthermore, the double-pion in comparison to the single-pion channel shows a higher sensitivity to higher excited resonances and a distinctly different Q2 dependence of the background amplitudes. The combined analysis of the single- and double-pion data reduces model dependent uncertainties significantly, which allows us to extract the resonant electrocoupling amplitudes with an unprecedented quality.
Enzyme replacement in Tay-Sachs disease.
von Specht, B U; Geiger, B; Arnon, R; Passwell, J; Keren, G; Goldman, B; Padeh, B
1979-06-01
Enzyme replacement therapy was attempted with two Tay-Sachs-diseased individuals--a 14-month-old child and a 7-week-old infant. Treatment consisted of repeated weekly intrathecal injections of pure hexosaminidase A. Injection of this enzyme resulted in almost complete disappearance of GM2 from the serum, but did not bring about dissolution of the GM2 membranous cytoplasmic bodies in the brain, as detected by electronmicroscopy. Both patients tolerated the treatment without apparent clinical complications, but no clear-cut improvement was noted as a result of prolonged injections of hexosaminidase A. Since this treatment was initiated in both an advanced stage and a very early stage of the disease, we conclude that enzyme replacement treatment by this route is not beneficial for patients with Tay-Sachs disease. PMID:572006
[Tay-Sachs disease: a case report].
Koch, S; Widhalm, K
1991-01-01
After an infection of the respiratory tract at the age of one a male infant showed progressive mental and physical retardation. Outstanding signs (e.g. baby doll face, startle reaction and frog position) as well as results of special investigations (cherry red spots of the maculae, short tubular bones) were suspicious for the presence of a lipidstorage disease, that could be identified as Tay-Sachs disease because of absent hexosaminidase A-activity in the patient's serum. Inspite the very low incidence of Tay-Sachs disease in our population, compared with a frequency of 1: 1200 in Ashkenzi Jews, the importance of establishing a diagnosis, based on typical clinical features and biochemical results, has to be emphasized. Genetic consultation is the only point of influence in positive family history, for attempts of causal therapy are not successful at present. PMID:1838805
Tay Sachs disease: an autopsy case report.
Jadhav, Meenal Vitthal; Landge, Meenal P; Sawaimoon, Satyakam K; Harke, Arun B; Deshmukh, Sanjay D
2005-10-01
This report describes a case report of a postmortem performed on a 5-year old patient of Tay-Sachs disease, presenting with failure to thrive, muscular flaccidity, and cherry-red spots on macula on fundoscopy. There was no history of similarly affected sibling or any other family member. The diagnosis was confirmed by enzyme studies. At postmortem, there was no organomegaly. The brain, on microscopy, showed vacuolated swollen neurons. PMID:16366100
The Dirac form factor predicts the Pauli form factor in the Endpoint Model
NASA Astrophysics Data System (ADS)
Dagaonkar, Sumeet K.; Jain, Pankaj; Ralston, John P.
2016-07-01
We compute the momentum-transfer dependence of the proton Pauli form factor F2 in the Endpoint overlap Model. We find the model correctly reproduces the scaling of the ratio of F2 with the Dirac form factor F1 observed at the Jefferson Laboratory. The calculation uses the leading-power, leading-twist Dirac structure of the quark light-cone wave function and the same endpoint dependence previously determined from the Dirac form factor F1. There are no parameters and no adjustable functions in the Endpoint Model's prediction for the scaling behavior of F2. The model's predicted momentum dependence of the ratio F2(Q2)/F1(Q2) is quite insensitive to the endpoint wave function, which explains why the observed ratio scales like 1 / Q down to rather low momentum transfers. We also fit the magnitude of this ratio by adjusting the parameters of the wave function. The Endpoint Model appears to be the only comprehensive model consistent with all form factor information as well as reproducing fixed-angle proton-proton scattering at large momentum transfer. Any one of the processes is capable of predicting the others.
Optimized perturbation theory: the pion form factor
Gupta, R.
1981-10-01
The order ..cap alpha../sup 2//sub s/(Q/sup 2/) corrections to the pion form-factor F/sub ..pi../(Q/sup 2/) are calculated using perturbative QCD and dimensional regularization. The result is compared in the MS and MOM subtraction schemes and plotted as a function of Q/sup 2//Q/sup 2/ where Q is the subtraction point. There is a large dependence on the scheme, the definition of the running coupling constant ..cap alpha../sub s/(Q/sup 2/) and the subtraction point Q. We find it best to invert the ..beta..-function equation for the definition of ..cap alpha../sub s/ rather than make an expansion in powers of log(Q/sup 2//..lambda../sup 2/). We study two methods to optimize the result with respect to Q: Stevenson's prescription and putting the 0(..cap alpha../sup 2//sub s/) term to zero. Both methods give almost the same value for Q/sup 2/F/sub ..pi../ and this value is scheme independent.
Proton Form Factor Measurements at Jefferson Lab
Charles Perdrisat; Vina Punjabi
2004-09-27
In two experiments at Jefferson Lab in Hall A, the first one in 1998 and the second in 2000, the ratio of the electromagnetic form factors of the proton was obtained by measuring P{sub t} and P{sub ell}, the transverse and longitudinal recoil proton polarization components, respectively, in {rvec e}p {yields} e{rvec p}; the ratio G{sub E{sub p}}/G{sub M{sub p}} is proportional to P{sub t}/P{sub {ell}}. Simultaneous measurement of P{sub t} and P{sub {ell}} provides good control of the systematic uncertainty. The first measurement of G{sub E{sub p}}/G{sub M{sub p}} ratio was made to Q{sup 2} = 3.5 GeV{sup 2} and the second measurement to Q{sup 2} = 5.6 GeV{sup 2}. The results from these two experiments indicate that the ratio scales like 1/Q{sup 2}, in stark contrast with cross section data analyzed by the Rosenbluth separation method which gives a constant value for this ratio. The incompatibility of the recoil polarization results with most of the Rosenbluth separation results appears now well established above Q{sup 2} of about 3 GeV{sup 2}. The consensus at the present time is that the interference of the two-photon exchange with the Born term, which had been deemed negligible until recently, might explain the discrepancy between the results of the two techniques; the possibility that the discrepancy is due to incomplete radiative correction has also been recently discussed.
Camci, Ugur; Kucukakca, Yusuf
2007-10-15
We consider some scalar-coupled theories of gravity, including induced gravity, and study the Noether symmetries of Bianchi I, Bianchi III, and Kantowski-Sachs cosmological models for this theory. For various forms of coupling of the scalar field with gravity, some potentials are found in these cosmological models under the assumption that the Lagrangian admits Noether symmetry. The solutions of the field equations for the considered models are presented by using the results obtained from the Noether symmetry. We also find the explicit form of the scalar field in terms of the conformal time for Bianchi I, III, and Kantowski-Sachs models.
National Tay-Sachs and Allied Diseases Association, Inc.
ERIC Educational Resources Information Center
Exceptional Parent, 1977
1977-01-01
Reviewed are the history and organization, purpose and programs, and public services of the National Tay-Sachs and Allied Diseases Association, an organization geared toward eradicating Tay-Sachs disease (a hereditary disorder affecting primarily Jewish infants which generally leads to deterioration and death by the child's fifth year). (SBH)
The National Tay Sachs and Allied Diseases Association.
ERIC Educational Resources Information Center
Zeitlin, Paula
1986-01-01
The National Tay-Sachs and Allied Diseases Association is involved in education, research, and prevention of Tay-Sachs, an inherited metabolic disorder which destroys the central nervous system, and over 30 related disorders. The group features a parent peer group network and a support group for carrier couples. (CL)
78 FR 24447 - Goldman Sachs Trust, et al.; Notice of Application
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... COMMISSION Goldman Sachs Trust, et al.; Notice of Application April 19, 2013. AGENCY: Securities and Exchange... the Act to invest in certain financial instruments. Applicants: Goldman Sachs Trust and Goldman Sachs Variable Insurance Trust (each a ``Trust,'' together, the ``Trusts''), Goldman Sachs Asset Management,...
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2013-05-06
... COMMISSION Goldman Sachs Trust II, et al.; Notice of Application April 29, 2013. AGENCY: Securities and... shareholder approval and would grant relief from certain disclosure requirements. APPLICANTS: Goldman Sachs Trust II (the ``Trust''), Goldman Sachs Asset Management L.P. (``GSAM'') and Goldman Sachs...
Virtuality Distributions and Pion Transition Form Factor
Radyushkin, Anatoly V.
2015-03-01
Using the example of hard exclusive transition process γ*γ → π0 at the handbag level, we outline basics of a new approach to transverse momentum dependence in hard processes. In coordinate representation, matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p, are functions of (pz) and z2 parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+=0, we introduce the transverse momentum distribution amplitude (TMDA) Ψ(x, k_perp), and write it in terms of VDA Φ(x,σ). We propose models for softmore » VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data. We also discuss the generation of hard tails of TMDAs from initially soft forms.« less
Virtuality Distributions and Pion Transition Form Factor
NASA Astrophysics Data System (ADS)
Radyushkin, A. V.
2015-02-01
Using the example of hard exclusive transition process γ*γ → π0 at the handbag level, we outline basics of a new approach to transverse momentum dependence in hard processes. In coordinate representation, matrix elements of operators (in the simplest case, bilocal 𝒪(0, z)) describing a hadron with momentum p, are functions of (pz) and z2 parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+ = 0, we introduce the transverse momentum distribution amplitude (TMDA) Ψ(x, k⊥), and write it in terms of VDA Φ(x, σ). We propose models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data. We also discuss the generation of hard tails of TMDAs from initially soft forms.
Julius Sachs (1832–1897) and the Unity of Life
Kutschera, Ulrich; Baluška, František
2015-01-01
In 1865, the German botanist Julius Sachs published a seminal monograph entitled Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) and hence became the founder of a new scientific discipline that originated 150 y ago. Here, we outline the significance of the achievements of Sachs. In addition, we document, with reference to his Vorlesungen über Pflanzen-Physiologie (Lectures on the Physiology of Plants, 1882), that Sachs was one of the first experimentalists who proposed the functional unity of all organisms alive today (humans, animals, plants and other “vegetable” organisms, such as algae, cyanophyceae, fungi, myxomycetes, and bacteria). PMID:26359706
Constant mean curvature slicings of Kantowski-Sachs spacetimes
Heinzle, J. Mark
2011-04-15
We investigate existence, uniqueness, and the asymptotic properties of constant mean curvature (CMC) slicings in vacuum Kantowski-Sachs spacetimes with positive cosmological constant. Since these spacetimes violate the strong energy condition, most of the general theorems on CMC slicings do not apply. Although there are in fact Kantowski-Sachs spacetimes with a unique CMC foliation or CMC time function, we prove that there also exist Kantowski-Sachs spacetimes with an arbitrary number of (families of) CMC slicings. The properties of these slicings are analyzed in some detail.
Julius Sachs (1832-1897) and the Unity of Life.
Kutschera, Ulrich; Baluška, František
2015-01-01
In 1865, the German botanist Julius Sachs published a seminal monograph entitled Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) and hence became the founder of a new scientific discipline that originated 150 y ago. Here, we outline the significance of the achievements of Sachs. In addition, we document, with reference to his Vorlesungen über Pflanzen-Physiologie (Lectures on the Physiology of Plants, 1882), that Sachs was one of the first experimentalists who proposed the functional unity of all organisms alive today (humans, animals, plants and other "vegetable" organisms, such as algae, cyanophyceae, fungi, myxomycetes, and bacteria). PMID:26359706
Virtuality Distributions and Pion Transition Form Factor
Radyushkin, Anatoly V.
2015-03-01
Using the example of hard exclusive transition process γ*γ → π^{0} at the handbag level, we outline basics of a new approach to transverse momentum dependence in hard processes. In coordinate representation, matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p, are functions of (pz) and z^{2} parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z^{2}. For intervals with z^{+}=0, we introduce the transverse momentum distribution amplitude (TMDA) Ψ(x, k_perp), and write it in terms of VDA Φ(x,σ). We propose models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data. We also discuss the generation of hard tails of TMDAs from initially soft forms.
Factor Structure of the Personality Research Form-E: A Maximum Likelihood Analysis.
ERIC Educational Resources Information Center
Fowler, Patrick C.
1985-01-01
Presents a five-factor, structural model of the Personality Research Form-E for 140 university undergraduates. All factors demonstrated an excellent level of similarity to those previously reported for other forms of the PRF, as well as to the conceptual scheme developed by Jackson (1974). (Author/JAC)
Conformal symmetry and pion form factor: Space- and timelike region
Choi, Ho-Meoyng; Ji, Chueng-Ryong
2008-06-01
We extend a recent analysis of the pion electromagnetic form factor constrained by the conformal symmetry to explore the timelike region. We show explicitly that the timelike form factor obtained by the analytic continuation of the spacelike form factor correctly satisfies the dispersion relation. Our results indicate that the quark spin and dynamical mass effects are crucial to yield the realistic features of the vector meson dominance phenomena.
HERMES impact for the access of Compton form factors
NASA Astrophysics Data System (ADS)
Kumerički, K.; Müller, D.; Murray, M.
2014-07-01
We utilize the DVCS asymmetry measurements of the HERMES collaboration for access to Compton form factors in the deeply virtual regime and to generalized parton distributions. In particular, the (almost) complete measurement of DVCS observables allows us to map various asymmetries into the space of Compton form factors, where we still rely in this analysis on dominance of twist-two associated Compton form factors. We compare this one-to-one map with local Compton form factor fits and a model dependent global fit.
Analytical evaluation of atomic form factors: Application to Rayleigh scattering
Safari, L.; Santos, J. P.; Amaro, P.; Jänkälä, K.; Fratini, F.
2015-05-15
Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.
Fragments of Science: Festschrift for Mendel Sachs
NASA Astrophysics Data System (ADS)
Ram, Michael
1999-11-01
The Table of Contents for the full book PDF is as follows: * Preface * Sketches at a Symposium * For Mendel Sachs * The Constancy of an Angular Point of View * Information-Theoretic Logic and Transformation-Theoretic Logic * The Invention of the Transistor and the Realization of the Hole * Mach's Principle, Newtonian Gravitation, Absolute Space, and Einstein * The Sun, Our Variable Star * The Inconstant Sun: Symbiosis of Time Variations of Sunspots, Atmospheric Radiocarbon, Aurorae, and Tree Ring Growth * Other Worlds * Super-Classical Quantum Mechanics * A Probabilistic Approach to the Phase Problem of X-Ray Crystallography * A Nonlinear Twist on Inertia Gives Unified Electroweak Gravitation * Neutrino Oscillations * On an Incompleteness in the General-Relativistic Description of Gravitation * All Truth is One * Ideas of Physics: Correspondence between Colleagues * The Influence of the Physics and Philosophy of Einstein's Relativity on My Attitudes in Science: An Autobiography
Tay Sachs and Related Storage Diseases: Family Planning
ERIC Educational Resources Information Center
Schneiderman, Gerald; And Others
1978-01-01
Based on interviews with 24 families, the article discusses family planning and the choices available to those families in which a child has previously died from Tay-Sachs or related lipid storage diseases. (IM)
Nucleon Form Factors experiments with 12 GeV CEBAF
Wojtsekhowski, B.
2008-10-13
A number of precision form factor experiments at high momentum transfer will be performed with the 11 GeV electron beam of CEBAF. We review the approved proposals and the conceptual schemes of several new suggestions. Form factor data will serve as a major input for the construction of a tomographic image of the nucleon.
Form factors in SU(3)-invariant integrable models
NASA Astrophysics Data System (ADS)
Belliard, S.; Pakuliak, S.; Ragoucy, E.; Slavnov, N. A.
2013-04-01
We study SU(3)-invariant integrable models solvable by a nested algebraic Bethe ansatz. We obtain determinant representations for form factors of diagonal entries of the monodromy matrix. This representation can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.
X-Ray Form Factor, Attenuation and Scattering Tables
National Institute of Standards and Technology Data Gateway
SRD 66 X-Ray Form Factor, Attenuation and Scattering Tables (Web, free access) This database collects tables and graphs of the form factors, the photoabsorption cross section, and the total attenuation coefficient for any element (Z <= 92).
Factors Influencing Students' Achievement in Form 5 Islamic Studies Subject
ERIC Educational Resources Information Center
bin Che Noh, Mohd Aderi; Omar, Noraini binti; bin Kasan, Hasnan
2013-01-01
This study is aimed at analyzing the factors influencing the achievements of students in the subject of Islamic Studies for Form 5 SPM (KBSM) in schools in the area of Samarahan, Sarawak. The factors analysed is attitude and interest. This is a survey based study and data was compiled from the survey forms which had the topic "Factors…
Orthopositronium decay form factors and two-photon correlations
Adkins, Gregory S.; Droz, Daniel R.; Rastawicki, Dominik; Fell, Richard N.
2010-04-15
We give results for the orthopositronium decay form factors through one-loop order. We use the form factors to calculate momentum correlations of the final-state photons
Relativistic quark model for the Omega- electromagnetic form factors
G. Ramalho, K. Tsushima, Franz Gross
2009-08-01
We compute the Omega- electromagnetic form factors and the decuplet baryon magnetic moments using a quark model application of the Covariant Spectator Theory. Our predictions for the Omega- electromagnetic form factors can be tested in the future by lattice QCD simulations at the physical strange quark mass.
ERIC Educational Resources Information Center
bin Pet, Mokhtar; Sihes, Ahmad Johari Hj
2015-01-01
This study aims to examine the external factors of form six teachers who can influence thinking domain form six teachers in their teaching. This study was conducted using a quantitative approach using questionnaires. A total of 300 form six teacher schools in Johor were chosen as respondents. The findings were obtained as student background…
Roaming form factors for the tricritical to critical Ising flow
NASA Astrophysics Data System (ADS)
Horváth, D. X.; Dorey, P. E.; Takács, G.
2016-07-01
We study the massless flows described by the staircase model introduced by Al.B. Zamolodchikov through the analytic continuation of the sinh-Gordon S-matrix, focusing on the renormalisation group flow from the tricritical to the critical Ising model. We show that the properly defined roaming limits of certain sinh-Gordon form factors are identical to the form factors of the order and disorder operators for the massless flow. As a by-product, we also construct form factors for a semi-local field in the sinh-Gordon model, which can be associated with the twist field in the ultraviolet limiting free massless bosonic theory.
Low-energy expansion of meson form factors
NASA Astrophysics Data System (ADS)
Gasser, J.; Leutwyler, H.
We calculate the corrections to various low-energy theorems concerning the behaviour of the pseudoscalar meson form factors near t=0. In particular we discuss (i) the Ademollo-Gatto theorem, (ii) Sirlin's relation between the Kl3 form factor ƒ +Kπ (t) and the electromagnetic form factors, (iii) the Callan-Treiman relation, and (iv) the Dashen-Weinstein relation, which connects the slope λ0 of ƒ 0Kπ (t) with the ratio FK/ Fπ. Furthermore, we point out a remarkable isospin breaking effect which is clearly visible in the experimental rates of the decays K +→ π0e +ν, K 0→ π-e +ν.
Longitudinal vector form factors in weak decays of nuclei
Šimkovic, F.; Kovalenko, S.; Krivoruchenko, M. I.
2015-10-28
The longitudinal form factors of the weak vector current of particles with spin J = 1/2 and isospin I = 1/2 are determined by the mass difference and the charge radii of members of the isotopic doublets. The most promising reactions to measure these form factors are the reactions with large momentum transfers involving the spin-1/2 isotopic doublets with a maximum mass splitting. Numerical estimates of longitudinal form factors are given for nucleons and eight nuclear spin-1/2 isotopic doublets.
The structure of the nucleon: Elastic electromagnetic form factors
Punjabi, V.; Perdrisat, C. F.; Jones, M. K.; Brash, E. J.; Carlson, C. E.
2015-07-10
Precise proton and neutron form factor measurements at Jefferson Lab, using spin observables, have recently made a significant contribution to the unraveling of the internal structure of the nucleon. Accurate experimental measurements of the nucleon form factors are a test-bed for understanding how the nucleon's static properties and dynamical behavior emerge from QCD, the theory of the strong interactions between quarks. There has been enormous theoretical progress, since the publication of the Jefferson Lab proton form factor ratio data, aiming at reevaluating the picture of the nucleon. We will review the experimental and theoretical developments in this field and discuss the outlook for the future.
Exploring strange nucleon form factors on the lattice
NASA Astrophysics Data System (ADS)
Babich, Ronald; Brower, Richard C.; Clark, Michael A.; Fleming, George T.; Osborn, James C.; Rebbi, Claudio; Schaich, David
2012-03-01
We discuss techniques for evaluating sea quark contributions to hadronic form factors on the lattice and apply these to an exploratory calculation of the strange electromagnetic, axial, and scalar form factors of the nucleon. We employ the Wilson gauge and fermion actions on an anisotropic 243×64 lattice, probing a range of momentum transfer with Q2<1GeV2. The strange electric and magnetic form factors, GEs(Q2) and GMs(Q2), are found to be small and consistent with zero within the statistics of our calculation. The lattice data favor a small negative value for the strange axial form factor GAs(Q2) and exhibit a strong signal for the bare strange scalar matrix element ⟨N|s¯s|N⟩0. We discuss the unique systematic uncertainties affecting the latter quantity relative to the continuum, as well as prospects for improving future determinations with Wilson-like fermions.
Personality Research Form: Factor Structure and Response Style Involvement
ERIC Educational Resources Information Center
Stricker, Lawrence J.
1974-01-01
Explores factor structure of the Personality Research Form (PRF) and examines the inventory's relations with response styles. In general, the PRF content scales correlate moderately with each other and with measures of acquiescence, social desirability, and defensiveness response biases. (Author)
Normalization Of Thermal-Radiation Form-Factor Matrix
NASA Technical Reports Server (NTRS)
Tsuyuki, Glenn T.
1994-01-01
Report describes algorithm that adjusts form-factor matrix in TRASYS computer program, which calculates intraspacecraft radiative interchange among various surfaces and environmental heat loading from sources such as sun.
Hadronic Form Factors in Asymptotically Free Field Theories
DOE R&D Accomplishments Database
Gross, D. J.; Treiman, S. B.
1974-01-01
The breakdown of Bjorken scaling in asymptotically free gauge theories of the strong interactions is explored for its implications on the large q{sup 2} behavior of nucleon form factors. Duality arguments of Bloom and Gilman suggest a connection between the form factors and the threshold properties of the deep inelastic structure functions. The latter are addressed directly in an analysis of asymptotically free theories; and through the duality connection we are then led to statements about the form factors. For very large q{sup 2} the form factors are predicted to fall faster than any inverse power of q{sup 2}. For the more modest range of q{sup 2} reached in existing experiments the agreement with data is fairly good, though this may well be fortuitous. Extrapolations beyond this range are presented.
Proton Form Factors Measurements in the Time-Like Region
Anulli, F.; /Frascati
2007-10-22
I present an overview of the measurement of the proton form factors in the time-like region. BABAR has recently measured with great accuracy the e{sup +}e{sup -} {yields} p{bar p} reaction from production threshold up to an energy of {approx} 4.5 GeV, finding evidence for a ratio of the electric to magnetic form factor greater than unity, contrary to expectation. In agreement with previous measurements, BABAR confirmed the steep rise of the magnetic form factor close to the p{bar p} mass threshold, suggesting the possible presence of an under-threshold N{bar N} vector state. These and other open questions related to the nucleon form factors both in the time-like and space-like region, wait for more data with different experimental techniques to be possibly solved.
Vector Meson Form Factors and Wave Functions from Holographic QCD
Hovhannes Grigoryan; Anatoly Radyushkin
2007-10-10
Based on the holographic dual model of QCD, we study 2- and 3-point functions of vector currents and derive form factors as well as wave functions for the vector mesons. As a result, generalized vector-meson dominance representation for form factors is obtained with a very specific VMD pattern. The calculated electric radius of the rho-meson is shown to be in a good agreement with predictions from lattice QCD.
From quarks and gluons to baryon form factors
Eichmann, Gernot
2012-01-01
I briefly summarize recent results for nucleon and Δ(1232) electromagnetic, axial and transition form factors in the Dyson–Schwinger approach. The calculation of the current diagrams from the quark–gluon level enables a transparent discussion of common features such as: the implications of dynamical chiral symmetry breaking and quark orbital angular momentum, the timelike structure of the form factors, and their interpretation in terms of missing pion-cloud effects. PMID:26766879
In-medium modified energy-momentum tensor form factors
NASA Astrophysics Data System (ADS)
Jung, Ju-Hyun; Yakhshiev, Ulugbek; Kim, Hyun-Chul
2014-04-01
In this talk, we report a recent investigation on the energy-momentum tensor form factors of the nucleon in nuclear medium, based on the framework of the in-medium modified chiral soliton model. The model was constructed by taking into account the influence of the surrounding environment to the mesonic sector (π-, ρ- and ω-meson properties). We briefly discuss the results of the energy-momentum tensor form factors.
Breather boundary form factors in sine-Gordon theory
NASA Astrophysics Data System (ADS)
Lencsés, M.; Takács, G.
2011-11-01
A previously conjectured set of exact form factors of boundary exponential operators in the sinh-Gordon model is tested against numerical results from boundary truncated conformal space approach in boundary sine-Gordon theory, related by analytic continuation to sinh-Gordon model. We find that the numerical data strongly support the validity of the form factors themselves; however, we also report a discrepancy in the case of diagonal matrix elements, which remains unresolved for the time being.
Deuteron form factor measurements at low momentum transfers
NASA Astrophysics Data System (ADS)
Schlimme, B. S.; Achenbach, P.; Beričič, J.; Böhm, R.; Bosnar, D.; Correa, L.; Distler, M. O.; Esser, A.; Fonvieille, H.; Friščić, I.; Griffioen, K. A.; Huan, Y.; Kegel, S.; Kohl, Y.; Merkel, H.; Mihovilovič, M.; Müller, J.; Müller, U.; Pochodzalla, J.; Schoth, M.; Schulz, F.; Sfienti, C.; Širca, S.; Štajner, S.; Thiel, M.; Weber, A.
2016-03-01
A precise measurement of the elastic electron-deuteron scattering cross section at four-momentum transfers of 0.24 fm-1 ≤ Q ≤ 2.7 fm-1 has been performed at the Mainz Microtron. In this paper we describe the utilized experimental setup and the necessary analysis procedure to precisely determine the deuteron charge form factor from these data. Finally, the deuteron charge radius rd can be extracted from an extrapolation of that form factor to Q2 = 0.
On Gravitational Form Factors and Transverse Spin Sum Rule
NASA Astrophysics Data System (ADS)
Chakrabarti, D.; Mondal, C.; Mukherjee, A.
2016-06-01
Using the light front wave functions of the scalar quark-diquark model for nucleon predicted by the soft-wall AdS/QCD, we calculate the flavor dependent gravitational form factors. We evaluate the matrix element of Pauli-Lubanski operator in this model and show that the intrinsic spin sum rule involves the higher twist form factor {bar{C}}. The longitudinal momentum densities in the transverse impact parameter space are also discussed for both unpolarized and transversely polarized nucleons.
Charm and bottom hadronic form factors with QCD sum rules
Bracco, M. E.; Rodrigues, B. O.; Cerqueira, A. Jr.
2013-03-25
We present a brief review of some calculations of form factors and coupling constants in vertices with charm and bottom mesons in the framework of QCD sum rules. We first discuss the motivation for this work, describing possible applications of these form factors to charm and bottom decays processes. We first make a summarize of the QCD sum rules method. We give special attention to the uncertainties of the method introducing by the intrinsic variation of the parameters. Finally we conclude.
Online Soil Science Lesson 3: Soil Forming Factors
Technology Transfer Automated Retrieval System (TEKTRAN)
This lesson explores the five major factors of soil formation, namely: 1) climate; 2) organisms; 3) time; 4) topography; and 5) parent material and their influence in forming soil. The distinction between active and passive factors, moisture and temperature regimes, organism and topographic influen...
Plant sulfur nutrition: From Sachs to Big Data
Kopriva, Stanislav
2015-01-01
Together with water and carbon dioxide plants require 14 essential mineral nutrients to finish their life cycle. The research in plant nutrition can be traced back to Julius Sachs, who was the first to experimentally prove the essentiality of mineral nutrients for plants. Among those elements Sachs showed to be essential is sulfur. Plant sulfur nutrition has been not as extensively studied as the nutrition of nitrogen and phosphate, probably because sulfur was not limiting for agriculture. However, with the reduction of atmospheric sulfur dioxide emissions sulfur deficiency has become common. The research in sulfur nutrition has changed over the years from using yeast and algae as experimental material to adopting Arabidopsis as the plant model as well as from simple biochemical measurements of individual parameters to system biology. Here the evolution of sulfur research from the times of Sachs to the current Big Data is outlined. PMID:26305261
A critique of Jeffrey D. Sachs's The end of poverty.
Henwood, Doug
2006-01-01
Jeffrey Sachs's The End of Poverty is a manifesto and how-to guide on ending extreme poverty around the world; it promotes the U.N. Millennium Development Goals. Sachs achieved fame with his policy package for the "stabilization" of Bolivia (which did nothing to relieve Bolivia's poverty), and became advisor to the Yeltsin government in Russia and to Poland, Slovenia, and Estonia as they began their transitions to capitalism (the last three mixed successes; Russia a thorough disaster). Sachs later became more prominent as a critic of development orthodoxy, and was economic advisor to the Jubilee 2000 movement. The End of Poverty is full of sharp critiques of Western imperialism, but his views on the rest of the development business are more conventional. PMID:16524171
Plant sulfur nutrition: From Sachs to Big Data.
Kopriva, Stanislav
2015-01-01
Together with water and carbon dioxide plants require 14 essential mineral nutrients to finish their life cycle. The research in plant nutrition can be traced back to Julius Sachs, who was the first to experimentally prove the essentiality of mineral nutrients for plants. Among those elements Sachs showed to be essential is sulfur. Plant sulfur nutrition has been not as extensively studied as the nutrition of nitrogen and phosphate, probably because sulfur was not limiting for agriculture. However, with the reduction of atmospheric sulfur dioxide emissions sulfur deficiency has become common. The research in sulfur nutrition has changed over the years from using yeast and algae as experimental material to adopting Arabidopsis as the plant model as well as from simple biochemical measurements of individual parameters to system biology. Here the evolution of sulfur research from the times of Sachs to the current Big Data is outlined. PMID:26305261
Tay-Sachs disease in Jacob sheep.
Torres, Paola A; Zeng, Bai Jin; Porter, Brian F; Alroy, Joseph; Horak, Fred; Horak, Joan; Kolodny, Edwin H
2010-12-01
Autopsy studies of four Jacob sheep dying within their first 6-8 months of a progressive neurodegenerative disorder suggested the presence of a neuronal storage disease. Lysosomal enzyme studies of brain and liver from an affected animal revealed diminished activity of hexosaminidase A (Hex A) measured with an artificial substrate specific for this component of β-hexosaminidase. Absence of Hex A activity was confirmed by cellulose acetate electrophoresis. Brain lipid analyses demonstrated the presence of increased concentrations of G(M2)-ganglioside and asialo-G(M2)-ganglioside. The hexa cDNA of Jacob sheep was cloned and sequenced revealing an identical number of nucleotides and exons as in human HexA and 86% homology in nucleotide sequence. A missense mutation was found in the hexa cDNA of the affected sheep caused by a single nucleotide change at the end of exon 11 resulting in skipping of exon 11. Transfection of normal sheep hexa cDNA into COS1 cells and human Hex A-deficient cells led to expression of Hex S but no increase in Hex A indicating absence of cross-species dimerization of sheep Hex α-subunit with human Hex β-subunits. Using restriction site analysis, the heterozygote frequency of this mutation in Jacob sheep was determined in three geographically separate flocks to average 14%. This large naturally occurring animal model of Tay-Sachs disease is the first to offer promise as a means for trials of gene therapy applicable to human infants. PMID:20817517
Flavor Decomposition of the Elastic Nucleon Electromagnetic Form Factors
NASA Astrophysics Data System (ADS)
Cates, G. D.; de Jager, C. W.; Riordan, S.; Wojtsekhowski, B.
2011-06-01
The u- and d-quark contributions to the elastic nucleon electromagnetic form factors have been determined by using experimental data on GEn, GMn, GEp, and GMp. Such a flavor separation of the form factors became possible up to negative four-momentum transfer squared Q2=3.4GeV2 with recent data on GEn from Hall A at Jefferson Lab. For Q2 above 1GeV2, for both the u and the d quark, the ratio of the Pauli and Dirac form factors, F2/F1, was found to be almost constant in sharp contrast to the behavior of F2/F1 for the proton as a whole. Also, again for Q2>1GeV2, both F2d and F1d are roughly proportional to 1/Q4, whereas the dropoff of F2u and F1u is more gradual.
Measurements of the Helium Form Factors at JLab
Khrosinkova, Elena
2007-10-26
An experiment to measure elastic electron scattering off {sup 3}He and {sup 4}He at large momentum transfers is presented. The experiment was carried out in the Hall A Facility of Jefferson Lab. Elastic electron scattering off {sup 3}He was measured at forward and backward electron scattering angles to extract the isotope's charge and magnetic form factors. The charge form factor of {sup 4}He will be extracted from forward-angle electron scattering angle measurements. The data are expected to significantly extend and improve the existing measurements of the three- and four-body form factors. The results will be crucial for the establishment of a canonical standard model for the few-body nuclear systems and for testing predictions of quark dimensional scaling and hybrid nucleon-quark models.
New results on strange form factors of the proton
Richard Holmes
2000-12-12
At the Thomas Jefferson National Accelerator Facility, we have studied the elastic scattering of polarized electrons from hydrogen. The resulting parity-violating electroweak asymmetry is sensitive to the contributions of strange quarks to the nucleon form factors at a level that is of theoretical interest. Using events at a laboratory scattering angle of 12.3{sup o} and (Q{sup 2})=0.477 GeV/c, we measure the linear combination of strange form factors (G{sup n}{sub E}) + 0.39G{sup E}{sub M}/(G{sup py}{sub M}/mu{sub p}) = 0.091+/-0.054+/-0.039, where the first error is the quadratic sum of our systematic and statistical errors and the second error is due to uncertainty in nucleon form factors.
Nucleon to delta electromagnetic transition form factors in lattice QCD
Alexandrou, C.; Koutsou, G.; Neff, H.; Negele, J. W.; Schroers, W.; Tsapalis, A.
2008-04-15
The electromagnetic nucleon to {delta} transition form factors are evaluated using two degenerate flavors of dynamical Wilson fermions and using dynamical sea staggered fermions with domain-wall valence quarks. The two subdominant quadrupole form factors are evaluated for the first time in full QCD to sufficient accuracy to exclude a zero value, which is taken as a signal for deformation in the nucleon-{delta} system. For the Coulomb quadrupole form factor the unquenched results begin to deviate from the quenched results at low q{sup 2} indicating that dynamical lattice results are closer to experiment. This can be taken as a first confirmation of the expected importance of pion cloud contributions on this quantity.
Measuring Form Factors and Structure Functions with CLAS
G.P. Gilfoyle
2007-09-10
The physics program at the Thomas Jefferson National Accelerator Facility includes a strong effort to measure form factors and structure functions to probe the structure of hadronic matter, reveal the nature of confinement, and develop an understanding of atomic nuclei using quark-gluon degrees of freedom. The CLAS detector is a large acceptance device occupying one of the end stations. We discuss here two programs that use CLAS; measuring the magnetic form factor of the neutron and the virtual photon asymmetry of the proton. The form factor has been measured with unprecedented kinematic coverage and precision up to Q2=4.7 GeV2 and is consistent within 5%-10% of the dipole parameterization. The proton virtual photon asymmetry has been measured across a wide range in Bjorken x. The data exceed the SU(6)-symmetric quark prediction and show evidence of a smooth approach to the scaling limit prescribed by perturbative QCD.
The structure of the nucleon: Elastic electromagnetic form factors
Punjabi, V.; Perdrisat, C. F.; Jones, M. K.; Brash, E. J.; Carlson, C. E.
2015-07-10
Precise proton and neutron form factor measurements at Jefferson Lab, using spin observables, have recently made a significant contribution to the unraveling of the internal structure of the nucleon. Accurate experimental measurements of the nucleon form factors are a test-bed for understanding how the nucleon's static properties and dynamical behavior emerge from QCD, the theory of the strong interactions between quarks. There has been enormous theoretical progress, since the publication of the Jefferson Lab proton form factor ratio data, aiming at reevaluating the picture of the nucleon. We will review the experimental and theoretical developments in this field and discussmore » the outlook for the future.« less
The Proton Form Factor Ratio Measurements at Jefferson Lab
Punjabi, Vina A.; Perdrisat, Charles F.
2014-03-01
The ratio of the proton form factors, G{sub Ep}/G{sub Mp}, has been measured from Q{sup 2} of 0.5 GeV{sup 2} to 8.5 GeV{sup 2}, at the Jefferson Laboratory, using the polarization transfer method. This ratio is extracted directly from the measured ratio of the transverse and longitudinal polarization components of the recoiling proton in elastic electron-proton scattering. The discovery that the proton form factor ratio measured in these experiments decreases approximately linearly with four-momentum transfer, Q{sup 2}, for values above ~1 GeV{sup 2}, is one of the most significant results to come out of JLab. These results have had a large impact on progress in hadronic physics; and have required a significant rethinking of nucleon structure. The increasingly common use of the double-polarization technique to measure the nucleon form factors, in the last 15 years, has resulted in a dramatic improvement of the quality of all four nucleon electromagnetic form factors, G{sub Ep}, G{sub Mp}, G{sub En} and G{sub Mn}. There is an approved experiment at JLab, GEP(V), to continue the ratio measurements to 12 GeV{sup 2}. A dedicated experimental setup, the Super Bigbite Spectrometer (SBS), will be built for this purpose. It will be equipped with a focal plane polarimeter to measure the polarization of the recoil protons. The scattered electrons will be detected in an electromagnetic calorimeter. In this presentation, I will review the status of the proton elastic electromagnetic form factors and discuss a number of theoretical approaches to describe nucleon form factors.
Master integrals for the four-loop Sudakov form factor
NASA Astrophysics Data System (ADS)
Boels, Rutger H.; Kniehl, Bernd A.; Yang, Gang
2016-01-01
The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally (N = 4) supersymmetric Yang-Mills theory (SYM) in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. The simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was largely obtained in integrand form in a previous work for N = 4 SYM, up to a free parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP) identities using a modified version of Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. Moreover, two of the integral topologies vanish after reduction. The appearing master integrals are cross-checked using independent algebraic-geometry techniques explored in the Mint package. The latter results provide the basis of master integrals applicable to generic form factors, including those in Quantum Chromodynamics. Discrepancies between explicitly solving the IBP relations and the MINT approach are highlighted. Remaining bottlenecks to completing the computation of the four-loop non-planar cusp anomalous dimension in N = 4 SYM and beyond are identified.
The B → K* form factors on the lattice
NASA Astrophysics Data System (ADS)
Agadjanov, Andria; Bernard, Véronique; Meißner, Ulf-G.; Rusetsky, Akaki
2016-09-01
The extraction of the B →K* transition form factors from lattice data is studied, applying non-relativistic effective field theory in a finite volume. The possible mixing of πK and ηK states is taken into account. The two-channel analogue of the Lellouch-Lüscher formula is reproduced. Due to the resonance nature of the K*, an equation is derived, which allows to determine the form factors at the pole position in a process-independent manner. The infinitely-narrow width approximation of the results is discussed.
Form factor of pNIPAM microgels in overpacked states
Gasser, U.; Hyatt, J. S.; Lietor-Santos, J.-J.; Fernandez-Nieves, A.; Herman, E. S.; Lyon, L. A.
2014-07-21
We study the form factor of thermoresponsive microgels based on poly(N-isopropylacrylamide) at high generalized volume fractions, ζ, where the particles must shrink or interpenetrate to fit into the available space. Small-angle neutron scattering with contrast matching techniques is used to determine the particle form factor. We find that the particle size is constant up to a volume fraction roughly between random close packing and space filling. Beyond this point, the particle size decreases with increasing particle concentration; this decrease is found to occur with little interpenetration. Noteworthily, the suspensions remain liquid-like for ζ larger than 1, emphasizing the importance of particle softness in determining suspension behavior.
Electromagnetic form factors of the Δ with D-waves
Ramalho, Gilberto T.F.; Pena, Maria Teresa; Gross, Franz L.
2010-06-01
The electromagnetic form factors of the Δ baryon are evaluated within the framework of a covariant spectator quark model, where S and D-states are included in the Δ wave function. We predict all the four Δ multipole form factors: the electric charge G_{E0}, the magnetic dipole G_{M1}, the electric quadrupole G_{E2} and the magnetic octupole G_{M3}. We compare our predictions with other theoretical calculations. Our results are compatible with the available experimental data and recent lattice QCD data.
Pion electromagnetic form factor in the Covariant Spectator Theory
Biernat, Elmar P.; Gross, Franz L.; Pena, Teresa; Stadler, Alfred
2014-01-01
The pion electromagnetic form factor at spacelike momentum transfer is calculated in relativistic impulse approximation using the Covariant Spectator Theory. The same dressed quark mass function and the equation for the pion bound-state vertex function as discussed in the companion paper are used for the calculation, together with a dressed quark current that satisfies the Ward-Takahashi identity. The results obtained for the pion form factor are in agreement with experimental data, they exhibit the typical monopole behavior at high momentum transfer and they satisfy some remarkable scaling relations.
Electromagnetic Form Factors of Hadrons in Quantum Field Theories
Dominguez, C. A.
2008-10-13
In this talk, recent results are presented of calculations of electromagnetic form factors of hadrons in the framework of two quantum field theories (QFT), (a) Dual-Large N{sub c} QCD (Dual-QCD{sub {infinity}}) for the pion, proton, and {delta}(1236), and (b) the Kroll-Lee-Zumino (KLZ) fully renormalizable Abelian QFT for the pion form factor. Both theories provide a QFT platform to improve on naive (tree-level) Vector Meson Dominance (VMD). Dual-QCD{sub {infinity}} provides a tree-level improvement by incorporating an infinite number of zero-width resonances, which can be subsequently shifted from the real axis to account for the time-like behaviour of the form factors. The renormalizable KLZ model provides a QFT improvement of VMD in the framework of perturbation theory. Due to the relative mildness of the {rho}{pi}{pi} coupling, and the size of loop suppression factors, the perturbative expansion is well defined in spite of this being a strong coupling theory. Both approaches lead to considerable improvements of VMD predictions for electromagnetic form factors, in excellent agreement with data.
Pseudo-scalar form factors at three loops in QCD
NASA Astrophysics Data System (ADS)
Ahmed, Taushif; Gehrmann, Thomas; Mathews, Prakash; Rana, Narayan; Ravindran, V.
2015-11-01
The coupling of a pseudo-scalar Higgs boson to gluons is mediated through a heavy quark loop. In the limit of large quark mass, it is described by an effective Lagrangian that only admits light degrees of freedom. In this effective theory, we compute the three-loop massless QCD corrections to the form factor that describes the coupling of a pseudo-scalar Higgs boson to gluons. Due to the axial anomaly, the pseudo-scalar operator for the gluonic field strength mixes with the divergence of the axial vector current. Working in dimensional regularization and using the 't Hooft-Veltman prescription for the axial vector current, we compute the three-loop pseudo-scalar form factors for massless quarks and gluons. Using the universal infrared factorization properties, we independently derive the three-loop operator mixing and finite operator renormalisation from the renormalisation group equation for the form factors, thereby confirming recent results in the operator product expansion. The finite part of the three-loop form factor is an important ingredient to the precise prediction of the pseudo-scalar Higgs boson production cross section at hadron colliders. We discuss potential applications and derive the hard matching coefficient in soft-collinear effective theory.
Pion Electromagnetic Form Factor in Virtuality Distribution Formalism
Radyushkin, Anatoly V.
2016-01-01
We discuss two applications of the {\\it Virtuality Distribution Amplitudes} (VDA) formalism developed in our recent papers. We start with an overview of the main properties of the pion distribution amplitude emphasizing the quantitative measures of its width, and possibility to access them through the pion transition form factor studies. We formulate the basic concepts of the VDA approach and introduce the pion {\\it transverse momentum distribution amplitude} (TMDA) which plays, in a covariant Lagrangian formulation, a role similar to that of the pion wave function in the 3-dimensional Hamiltonian light-front approach. We propose simple factorized models for soft TMDAs, and use them to describe existing data on the pion transition form factor, thus fixing the scale determining the size of the transverse-momentum effects. Finally, we apply the VDA approach to the one-gluon exchange contribution for the pion electromagnetic form factor. We observe a very late $Q^2 \\gtrsim 20$ GeV$^2$ onset of transition to the asymptotic pQCD predictions and show that in the $Q^2 \\lesssim 10$ GeV$^2$ region there is essentially no sensitivity to the shape of the pion distribution amplitude. Furthermore, the magnitude of the one-gluon exchange contribution in this region is estimated to be an order of magnitude below the Jefferson Lab data, thus leaving the Feynman mechanism as the only one relevant to the pion electromagnetic form factor behavior for accessible $Q^2$.
Saul R. Korey Lecture. Molecular genetics of Tay-Sachs and related disorders: a personal account.
Suzuki, K
1994-07-01
The history of human genetic lysosomal disorders began in 1881 with the description of what is now known as Tay-Sachs disease. In the early 1960s, when I entered the field while I was a neurology resident, the first phase of studies of lysosomal disorders was being replaced with the second analytical biochemistry phase. Saul Korey, the first Chairman of the Department of Neurology, Albert Einstein College of Medicine, initiated the first integrated approach with a team consisting of clinical neurologists, neuropathologists, electron microscopists, cell biologists, organic chemists, and enzymologists. Despite his tragic death in 1963 in his mid-forties, the field flourished along the line of his vision through the third enzymology phase to the fourth and current molecular biology phase. The concept of Tay-Sachs disease as the only ganglioside storage disease has expanded to two forms of gangliosidoses, GM1- and GM2-gangliosidoses, and the latter into three distinct genetic disorders. Tay-Sachs disease, Sandhoff disease and the GM2 activator protein deficiency. More recently, all three genes coding for the three proteins each responsible for distinct genetic forms of GM2-gangliosidosis--beta-hexosaminidase alpha and beta subunits and the GM2 activator protein--have been cloned and many disease-causing mutations have been identified. We have reached the halfway point in our quest for eventual understanding of the pathogenesis and effective treatment of these disorders, starting from the clinical phenotype through biochemistry to the gene. With this new knowledge on the gene level, we should be tracing the route back to enzymology, biology and pathogenetic mechanism of these disorders in the years to come.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8021707
The Modern description of semileptonic meson form factors
Hill, Richard J.
2006-06-01
I describe recent advances in our understanding of the hadronic form factors governing semileptonic meson transitions. The resulting framework provides a systematic approach to the experimental data, as a means of extracting precision observables, testing nonperturbative field theory methods, and probing a poorly understood limit of QCD.
Delta-Isobar magnetic form factor in QCD
Belyaev, Vladimir
1993-01-01
We consider the QCD sum rules approach for Delta-isobar magnetic form factor in the infra-red region $0
Measurement of the pion form factor at higher energies
Mack, D.J.
1994-04-01
One of the strongest arguments for increasing the nominal CEBAF beam energy to equal or exceed 6 GeV is that one would be able to make quality high Q{sup 2} measurements of the charged pion form factor.
JLAB Measurements of the Deuteron Electric and Magnetic Form Factors
Gerassimos G. Petratos
2000-12-12
Large-momentum transfer JLab measurements of the deuteron electric and magnetic form factors are reported. The data are compared to theoretical models based on the relativistic impulse approximation with the inclusion of meson-exchange currents, and to predictions of quark-dimensional scaling and perturbative QCD.
Personality Research Form: Factor Structure and Response Style Involvement.
ERIC Educational Resources Information Center
Stricker, Lawrence J.
The aims of this study were (1) to explore the factor structure of the Personality Research Form (PRF) and (2) to examine the inventory's relations with response styles. In general the PRF content scales correlated moderately with each other and with measures of acquiesence, social desirability, and defensiveness response Biases. Six oblique…
Factor Content of the Hill Interaction Matrix--Form B
ERIC Educational Resources Information Center
Drummond, Robert J.; McIntire, Walter G.
1976-01-01
Investigates the construct validity of the Hill Interaction Matrix--Form B, a 64-item instrument designed to assess preferred modes of interaction in group settings. A factor analysis was performed by using 134 subjects. Results indicate that the items and the conceptual format are appropriate. (Author)
The Super Bigbite Project: A Study of Nucleon Form Factors
Jager, Kees de
2010-06-01
A proposed set of instrumentation, collectively referred to as the Super Bigbite project, is presented. Used in three different con figurations it will allow measurements of three nucleon electromagnetic form factors GEn, GEp, and GMn with unprecedented precision to Q2-values up to three times higher than existing data.
Nucleon form factors program with SBS at JLAB
Wojtsekhowski, Bogdan B.
2014-12-01
The physics of the nucleon form factors is the basic part of the Jefferson Laboratory program. We review the achievements of the 6-GeV era and the program with the 12- GeV beam with the SBS spectrometer in Hall A, with a focus on the nucleon ground state properties.
The Mainz high-precision proton form factor measurement
NASA Astrophysics Data System (ADS)
Bernauer, Jan
2011-04-01
Form factors offer a direct approach to fundamental properties of the nucleons like the radius and charge distribution. Renewed interest was stirred up by the 5 sigma discrepancy between a recent determination of the proton radius from the Lamb shift in muonic hydrogen and preceding electron scattering results. The low-q shape of the form factors might also contain a direct signal of a pion cloud around the nucleus and is a strong test of hadron models. In my talk, I will discuss the electron scattering experiment performed with the 3-spectrometer-facility of the A1 collaboration at MAMI in Mainz, Germany. The data set covers the Q2-range from 0.004 to 1 (GeV / c) 2 and includes about 1400 separate cross section measurements, spanning the range of scattering angles from below 20° to above 120° at six beam energies between 180 and 855 MeV, with statistical uncertainties below 0.4%. The 3-spectrometer-setup allowed for a simultaneous monitoring of the luminosity and overlapping and redundant measurements of the cross section to achieve stringent control over systematic uncertainties. Beam stabilization systems and redundant current measurements further limit systematic effects. The measured cross sections were analyzed with the standard Rosenbluth separation technique and by employing direct fits of a large set of form factor models. The high redundancy of the data set allowed us to extract the form factors up to 0.6 (GeV / c) 2 with very small uncertainties and to give a new, precise value for the proton radius from electron scattering. From the form factors, the charge distribution and Zemach moments were calculated. The latter constitute important input for the theoretical corrections of the muonic Lamb shift experiment. However, the revised values can not explain the discrepancy. Further possible explanations include higher order QED-corrections, vacuum effects or even physics beyond the standard model.
Rapid detection of fetal Mendelian disorders: Tay-Sachs disease.
Guetta, Esther; Peleg, Leah
2008-01-01
Tay-Sachs disease is an autosomal recessive storage disease caused by the impaired activity of the lysosomal enzyme hexosaminidase A. In this fatal disease, the sphingolipid GM2 ganglioside accumulates in the neurons. Due to high carrier rates and the severity of the disease, population screening and prenatal diagnosis of Tay-Sachs disease are routinely carried out in Israel. Laboratory diagnosis of Tay-Sachs is carried out with biochemical and DNA-based methods in peripheral and umbilical cord blood, amniotic fluid, and chorionic villi samples. The assay of hexosaminidase A (Hex A) activity is carried out with synthetic substrates, 4-methylumbelliferyl-6-sulfo-N-acetyl-beta-glucosaminide (4-MUGS) and 4-methylumbelliferil-N-acetyl-beta-glucosamine (4-MUG), and the DNA-based analysis involves testing for the presence of specific known mutations in the alpha-subunit gene of Hex A. Prenatal diagnosis of Tay-Sachs disease is accomplished within 24-48 h from sampling. The preferred strategy is to simultaneously carry out enzymatic analysis in the amniotic fluid supernatant or in chorionic villi and molecular DNA-based testing in an amniotic fluid cell-pellet or in chorionic villi. PMID:18425478
Tay-Sachs disease carrier screening: a 21-year experience.
D'Souza, G; McCann, C L; Hedrick, J; Fairley, C; Nagel, H L; Kushner, J D; Kessel, R
2000-01-01
This paper presents the findings of a community-based carrier screening program for Tay-Sachs disease, initiated on the University of Wisconsin-Madison campus in 1978. The Madison Community Tay-Sachs Screening Program (MCTSSP) is a collaborative, interdisciplinary program that organizes and conducts periodic screening for Tay-Sachs disease (TSD) for the purpose of identifying Tay-Sachs carriers. We present and analyze data on carrier detection with regard to various demographics, including family history of TSD, ancestry, gender, medication exposure, and illness. Individuals participating in the MCTSSP between 1978 and 1999 were primarily of the target population, and the carrier rate was within the expected range (1/25). Despite aggressive publicity efforts and a well-established program, attendance at the screens has declined. A recent survey of Jewish undergraduate students at the University of Wisconsin-Madison showed poor recall of family screen history and carrier status and reinforced the perception that utilization of the Madison screening program has been low. Ways to increase awareness of and interest in carrier screening for TSD are explored. PMID:11142756
Electromagnetic form factors and charge densities from hadrons to nuclei
Miller, Gerald A.
2009-10-15
A simple exact covariant model in which a scalar particle {psi} is modeled as a bound state of two different particles is used to elucidate relativistic aspects of electromagnetic form factors F(Q{sup 2}). The model form factor is computed using an exact covariant calculation of the lowest order triangle diagram. The light-front technique of integrating over the minus component of the virtual momentum gives the same result and is the same as the one obtained originally by Gunion et al. [Phys. Rev. D 8, 287 (1973)] by using time-ordered perturbation theory in the infinite-momentum frame. The meaning of the transverse density {rho}(b) is explained by providing a general derivation, using three spatial coordinates, of its relationship with the form factor. This allows us to identify a mean-square transverse size ={integral}d{sup 2}b b{sup 2}{rho}(b)=-4(dF/dQ{sup 2})(Q{sup 2}=0). The quantity is a true measure of hadronic size because of its direct relationship with the transverse density. We show that the rest-frame charge distribution is generally not observable by studying the explicit failure to uphold current conservation. Neutral systems of two charged constituents are shown to obey the conventional lore that the heavier one is generally closer to the transverse origin than the lighter one. It is argued that the negative central charge density of the neutron arises, in pion-cloud models, from pions of high longitudinal momentum that reside at the center. The nonrelativistic limit is defined precisely, and the ratio of the binding energy B to the mass M of the lightest constituent is shown to govern the influence of relativistic effects. It is shown that the exact relativistic formula for F(Q{sup 2}) is the same as the familiar one of the three-dimensional Fourier transform of a square of a wave function for very small values of B/M, but this only occurs for values of B/M less than about 0.001. For masses that mimic the quark-diquark model of
Dirac and Pauli form factors from lattice QCD
Collins, S.; Goeckeler, M.; Nobile, A.; Schaefer, A.; Haegler, Ph.; Horsley, R.; Winter, F.; Zanotti, J. M.; Nakamura, Y.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schroers, W.; Stueben, H.
2011-10-01
We present a comprehensive analysis of the electromagnetic form factors of the nucleon from a lattice simulation with two flavors of dynamical O(a)-improved Wilson fermions. A key feature of our calculation is that we make use of an extensive ensemble of lattice gauge field configurations with four different lattice spacings, multiple volumes, and pion masses down to m{sub {pi}{approx}1}80 MeV. We find that by employing Kelly-inspired parametrizations for the Q{sup 2} dependence of the form factors, we are able to obtain stable fits over our complete ensemble. Dirac and Pauli radii and the anomalous magnetic moments of the nucleon are extracted and results at light quark masses provide evidence for chiral nonanalytic behavior in these fundamental observables.
Measurement of the gamma gamma* -> pi0 transition form factor
Aubert, B.
2009-06-02
We study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -}{pi}{sup 0} in the single tag mode and measure the differential cross section d{sigma}/dQ{sup 2} and the {gamma}{gamma}* {yields} {pi}{sup 0} transition form factor in the mometum transfer range from 4 to 40 GeV{sup 2}. At Q{sup 2} > 10 GeV{sup 2} the measured form factor exceeds the asymptotic limit predicted by perturbative QCD. The analysis is based on 442 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.
Octet Baryon Electromagnetic Form Factors in a Relativistic Quark Model
Gilberto Ramalho, Kazuo Tsushima
2011-09-01
We study the octet baryon electromagnetic properties by applying the covariant spectator quark model, and provide covariant parametrization that can be used to study baryon electromagnetic reactions. While we use the lattice QCD data in the large pion mass regime (small pion cloud effects) to determine the parameters of the model in the valence quark sector, we use the nucleon physical and octet baryon magnetic moment data to parameterize the pion cloud contributions. The valence quark contributions for the octet baryon electromagnetic form factors are estimated by extrapolating the lattice parametrization in the large pion mass regime to the physical regime. As for the pion cloud contributions, we parameterize them in a covariant, phenomenological manner, combined with SU(3) symmetry. We also discuss the impact of the pion cloud effects on the octet baryon electromagnetic form factors and their radii.
Reanalysis of Rosenbluth measurements of the proton form factors
NASA Astrophysics Data System (ADS)
Gramolin, A. V.; Nikolenko, D. M.
2016-05-01
We present a reanalysis of the data from Stanford Linear Accelerator Center (SLAC) experiments E140 [R. C. Walker et al., Phys. Rev. D 49, 5671 (1994), 10.1103/PhysRevD.49.5671] and NE11 [L. Andivahis et al., Phys. Rev. D 50, 5491 (1994), 10.1103/PhysRevD.50.5491] on elastic electron-proton scattering. This work is motivated by recent progress in calculating the corresponding radiative corrections and by the apparent discrepancy between the Rosenbluth and polarization transfer measurements of the proton electromagnetic form factors. New, corrected values for the scattering cross sections are presented, as well as a new form factor fit in the Q2 range from 1 to 8.83 GeV2. We also provide a complete set of revised formulas to account for radiative corrections in single-arm measurements of unpolarized elastic electron-proton scattering.
Small form factor full parallax tiled light field display
NASA Astrophysics Data System (ADS)
Alpaslan, Zahir Y.; El-Ghoroury, Hussein S.
2015-03-01
With the recent introduction of Ostendo's Quantum Photonic Imager (QPI) display technology, a very small pixel pitch, emissive display with high brightness and low power consumption became available. We used QPI's to create a high performance light field display tiles with a very small form factor. Using 8 of these QPI light field displays tiled in a 4x2 array we created a tiled full parallax light field display. Each individual light field display tile combines custom designed micro lens array layers with monochrome green QPIs. Each of the light field display tiles can address 1000 x 800 pixels placed under an array of 20 x 16 lenslets with 500 μm diameters. The light field display tiles are placed with small gaps to create a tiled display of approximately 46 mm (W) x 17 mm (H) x 2 mm (D) in mechanical dimensions. The prototype tiled full parallax light field display demonstrates small form factor, high resolution and focus cues.
Bs→Kℓν form factors from lattice QCD
NASA Astrophysics Data System (ADS)
Bouchard, C. M.; Lepage, G. Peter; Monahan, Christopher; Na, Heechang; Shigemitsu, Junko
2014-09-01
We report the first lattice QCD calculation of the form factors for the standard model tree-level decay Bs→K ℓν. In combination with future measurement, this calculation will provide an alternative exclusive semileptonic determination of |Vub|. We compare our results with previous model calculations, make predictions for differential decay rates and branching fractions, and predict the ratio of differential branching fractions between Bs→Kτν and Bs→Kμν. We also present standard model predictions for differential decay rate forward-backward asymmetries and polarization fractions and calculate potentially useful ratios of Bs→K form factors with those of the fictitious Bs→ηs decay. Our lattice simulations utilize nonrelativistic QCD b and highly improved staggered light quarks on a subset of the MILC Collaboration 2+1 asqtad gauge configurations, including two lattice spacings and a range of light quark masses.
Nonlocal form factors for curved-space antisymmetric fields
NASA Astrophysics Data System (ADS)
Netto, Tibério de Paula; Shapiro, Ilya L.
2016-07-01
In a recent paper, Buchbinder, Kirillova, and Pletnev presented formal arguments concerning the quantum equivalence of free massive antisymmetric tensor fields of the second and third rank to the free Proca theory and massive scalar field with minimal coupling to gravity, respectively. We confirm this result using explicit covariant calculations of nonlocal form factors based on the heart-kernel technique and discuss the discontinuity of quantum contributions in the massless limit.
Axial form factor of the nucleon at large momentum transfers
NASA Astrophysics Data System (ADS)
Anikin, I. V.; Braun, V. M.; Offen, N.
2016-08-01
Motivated by the emerging possibilities to study threshold pion electroproduction at large momentum transfers at Jefferson Laboratory following the 12 GeV upgrade, we provide a short theory summary and an estimate of the nucleon axial form factor for large virtualities in the Q2=1 - 10 GeV2 range using next-to-leading-order light-cone sum rules.
Theoretical and Experimental Review on Proton Form Factors
NASA Astrophysics Data System (ADS)
Baldini Ferroli, Rinaldo; Pacetti, Simone
2014-12-01
During the last three lustra nucleon form factors experiments have lived a golden age, full of interesting results, that likely will continue and culminate when new data will come from BESIII, SND, CMD3 and PANDA, in the time-like region and, Jefferson Lab and A1 in the space-like region. On the other hand, from theoretical point of view, mainly concerning the possibility of descriptions in all kinematical regions, no great breakthrough has been made.
Stackable Form-Factor Peripheral Component Interconnect Device and Assembly
NASA Technical Reports Server (NTRS)
Somervill, Kevin M. (Inventor); Ng, Tak-kwong (Inventor); Torres-Pomales, Wilfredo (Inventor); Malekpour, Mahyar R. (Inventor)
2013-01-01
A stackable form-factor Peripheral Component Interconnect (PCI) device can be configured as a host controller or a master/target for use on a PCI assembly. PCI device may comprise a multiple-input switch coupled to a PCI bus, a multiplexor coupled to the switch, and a reconfigurable device coupled to one of the switch and multiplexor. The PCI device is configured to support functionality from power-up, and either control function or add-in card function.
Two-photon exchange corrections to the pion form factor
Peter G. Blunden; Melnitchouk, Wally; Tjon, John A.
2010-01-06
Here, we compute two-photon exchange corrections to the electromagnetic form factor of the pion, taking into account the finite size of the pion. Compared to the soft-photon approximation for the infrared divergent contribution which neglects hadron structure effects, the corrections are found to be ≲ 1% for small Q2 (Q2 < 0.1 GeV2), but increase to several percent for Q2 ≳ 1 GeV2 at extreme backward angles.
Helicity non-conserving form factor of the proton
Voutier, E.; Furget, C.; Knox, S.
1994-04-01
The study of the hadron structure in the high Q{sup 2} range contributes to the understanding of the mechanisms responsible for the confinement of quarks and gluons. Among the numerous experimental candidates sensitive to these mechanisms, the helicity non-conserving form factor of the proton is a privileged observable since it is controlled by non-perturbative effects. The authors investigate here the feasibility of high Q{sup 2} measurements of this form factor by means of the recoil polarization method in the context of the CEBAF 8 GeV facility. For that purpose, they discuss the development of a high energy proton polarimeter, based on the H({rvec p},pp) elastic scattering, to be placed at the focal plane of a new hadron spectrometer. It is shown that this experimental method significantly improves the knowledge of the helicity non-conserving form factor of the proton up to 10 GeV{sup 2}/c{sup 2}.
Strange vector form factors from parity-violating electron scattering
Kent Paschke, Anthony Thomas, Robert Michaels, David Armstrong
2011-06-01
The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and qbar q pairs which binds it. Early indications of a particularly large contribution from strange quarks in this sea to the spin and mass of the nucleon motivated an experimental program examining the role of these strange quarks in the nucleon vector form factors. The strangeness form factors can be extracted from the well-studied electromagnetic structure of the nucleon using parity-violation in electron-nuclear scattering to isolate the effect of the weak interaction. With high luminosity and polarization, and a very stable beam due to its superconducting RF cavities, CEBAF at Jefferson Lab is a precision instrument uniquely well suited to the challenge of measurements of the small parity-violating asymmetries. The techniques and results of the two major Jefferson Lab experimental efforts in parity-violation studies, HAPPEX and G0, as well as efforts to describe the strange form factors in QCD, will be reviewed.
Pion transverse charge density from timelike form factor data
Gerald Miller, Mark Strikman, Christian Weiss
2011-01-01
The transverse charge density in the pion can be represented as a dispersion integral of the imaginary part of the pion form factor in the timelike region. This formulation incorporates information from e+e- annihilation experiments and allows one to reconstruct the transverse density much more accurately than from the spacelike pion form factor data alone. We calculate the transverse density using an empirical parametrization of the timelike pion form factor and estimate that it is determined to an accuracy of ~10% at a distance b ~ 0.1 fm, and significantly better at larger distances. The density is found to be close to that obtained from a zero-width rho meson pole over a wide range and shows a pronounced rise at small distances. The resulting two-dimensional image of the fast-moving pion can be interpreted in terms of its partonic structure in QCD. We argue that the singular behavior of the charge density at the center requires a substantial presence of pointlike configurations in the pion's partonic wave function, which can be probed in other high-momentum transfer processes.
The proton form factor ratio results from Jefferson Lab
Vina Punjabi
2012-09-01
The ratio of the proton form factors, GE p/GMp, has been measured extensively, from Q2 of 0.5 GeV2 to 8.5 GeV2, at the Jefferson Laboratory, using the polarization transfer method. This ratio is extracted directly from the measured ratio of the transverse and longitudinal polarization components of the recoiling proton in elastic electron-proton scattering. The polarization transfer results are of unprecedented high precision and accuracy, due in large part to the small systematic uncertainties associated with the experimental technique. There is an approved experiment at JLab, GEP(5), to continue the ratio measurements to 12 GeV2. A dedicated experimental setup, the Super Bigbite Spectrometer (SBS), will be built for this purpose. It will be equipped with a focal plane polarimeter to measure the polarization of the recoil protons. The scattered electrons will be detected in an electromagnetic calorimeter. In this presentation, I will review the status of the proton elastic electromagnetic form factors and discuss a number of theoretical approaches to describe nucleon form factors.
Meson Transition Form Factors in Light-Front Holographic QCD
Brodsky, Stanley J.; Cao, Fu-Guang; de Teramond, Guy F.; /Costa Rica U.
2011-06-22
We study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the q{bar q} component of the pion wavefunction, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0} {yields} {gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the q{bar q} component of the pion wavefunction P{sub q{bar q}} = 0.5 is required; thus giving indication that the contributions from higher Fock states in the pion light-front wavefunction need to be included in the analysis. The probability for the Fock state containing four quarks (anti-quarks) which follows from analyzing the hadron matrix elements, P{sub q{bar q}q{bar q}} {approx} 10%, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wavefunction. The results for the TFFs for the {eta} and {eta}{prime} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{prime} TFFs.
Neutron charge radius and the neutron electric form factor
Gentile, T. R.; Crawford, C. B.
2011-05-15
For nearly forty years, the Galster parametrization has been employed to fit existing data for the neutron electric form factor, G{sub E}{sup n}, vs the square of the four-momentum transfer, Q{sup 2}. Typically this parametrization is constrained to be consistent with experimental data for the neutron charge radius. However, we find that the Galster form does not have sufficient freedom to accommodate reasonable values of the radius without constraining or compromising the fit. In addition, the G{sub E}{sup n} data are now at sufficient precision to motivate a two-parameter fit (or three parameters if we include thermal neutron data). Here we present a modified form of a two-dipole parametrization that allows this freedom and fits both G{sub E}{sup n} (including recent data at both low and high four-momentum transfer) and the charge radius well with simple, well-defined parameters. Analysis reveals that the Galster form is essentially a two-parameter approximation to the two-dipole form but becomes degenerate if we try to extend it naturally to three parameters.
Electric and magnetic form factors of the proton
NASA Astrophysics Data System (ADS)
Bernauer, J. Â. C.; Distler, M. Â. O.; Friedrich, J.; Walcher, Th.; Achenbach, P.; Ayerbe Gayoso, C.; Böhm, R.; Bosnar, D.; Debenjak, L.; Doria, L.; Esser, A.; Fonvieille, H.; Gómez Rodríguez de la Paz, M.; Friedrich, J. Â. M.; Makek, M.; Merkel, H.; Middleton, D. Â. G.; Müller, U.; Nungesser, L.; Pochodzalla, J.; Potokar, M.; Sánchez Majos, S.; Schlimme, B. Â. S.; Širca, S.; Weinriefer, M.; A1 Collaboration
2014-07-01
This paper describes a precise measurement of electron scattering off the proton at momentum transfers of 0.003≲Q2≲1 GeV2. The average point-to-point error of the cross sections in this experiment is ˜0.37%. These data are used for a coherent new analysis together with all world data of unpolarized and polarized electron scattering from the very smallest to the highest momentum transfers so far measured. The extracted electric and magnetic form factors provide new insight into their exact shape, deviating from the classical dipole form, and of structure on top of this gross shape. The data reaching very low Q2 values are used for a new determination of the electric and magnetic radii. An empirical determination of the two-photon-exchange correction is presented. The implications of this correction on the radii and the question of a directly visible signal of the pion cloud are addressed.
Scattering form factors for self-assembled network junctions
NASA Astrophysics Data System (ADS)
Foster, T.; Safran, S. A.; Sottmann, T.; Strey, R.
2007-11-01
The equilibrium microstructures in microemulsions and other self-assembled systems show complex, connected shapes such as symmetric bicontinuous spongelike structures and asymmetric bicontinuous networks formed by cylinders interconnected at junctions. In microemulsions, these cylinder network microstructures may mediate the structural transition from a spherical or globular phase to the bicontinuous microstructure. To understand the structural and statistical properties of such cylinder network microstructures as measured by scattering experiments, models are needed to extract the real-space structure from the scattering data. In this paper, we calculate the scattering functions appropriate for cylinder network microstructures. We focus on such networks that contain a high density of network junctions that connect the cylindrical elements. In this limit, the network microstructure can be regarded as an assembly of randomly oriented, closed packed network junctions (i.e., the cylinder scattering contributions are neglected). Accordingly, the scattering spectrum of the network microstructure can be calculated as the product of the junction number density, the junction form factor, which describes the scattering from the surface of a single junction, and a structure factor, which describes the local correlations of different junctions due to junction interactions (including their excluded volume). This approach is applied to analyze the scattering data from a bicontinuous microemulsion with equal volumes of water and oil. In a second approach, we included the cylinder scattering contribution in the junction form factor by calculating the scattering intensity of Y junctions to which three rods with spherical cross section are attached. The respective theoretical predictions are compared with results of neutron scattering measurements on a water-in-oil microemulsion with a connected microstructure.
Proton Form Factor Measurements Using Polarization Method: Beyond Born Approximation
Pentchev, Lubomir
2008-10-13
Significant theoretical and experimental efforts have been made over the past 7 years aiming to explain the discrepancy between the proton form factor ratio data obtained at JLab using the polarization method and the previous Rosenbluth measurements. Preliminary results from the first high precision polarization experiment dedicated to study effects beyond Born approximation will be presented. The ratio of the transferred polarization components and, separately, the longitudinal polarization in ep elastic scattering have been measured at a fixed Q{sup 2} of 2.5 GeV{sup 2} over a wide kinematic range. The two quantities impose constraints on the real part of the ep elastic amplitudes.
CEBAF at higher energies and the kaon electromagnetic form factor
Baker, O.K.
1994-04-01
The electromagnetic production of strangeness, the physics of exciting systems having strangeness degrees of freedom (production of hadrons with one or more strange constituent quarks) using electromagnetic probes (real or virtual photons), is one of the frontier areas of research which will be investigated at the Continuous Electron Beam Accelerator Facility (CEBAF) when it becomes operational. CEBAF is expected to have an important impact upon this field of research using its specialized set of detection instruments and high quality electron beam. This paper focusses upon one aspect of the associated production of strangeness - the determination of the kaon electromagnetic form factor at high squared momentum transfers.
Baryon octet electromagnetic form factors in a confining NJL model
NASA Astrophysics Data System (ADS)
Carrillo-Serrano, Manuel E.; Bentz, Wolfgang; Cloët, Ian C.; Thomas, Anthony W.
2016-08-01
Electromagnetic form factors of the baryon octet are studied using a Nambu-Jona-Lasinio model which utilizes the proper-time regularization scheme to simulate aspects of colour confinement. In addition, the model also incorporates corrections to the dressed quarks from vector meson correlations in the t-channel and the pion cloud. Comparison with recent chiral extrapolations of lattice QCD results shows a remarkable level of consistency. For the charge radii we find the surprising result that rEp < rEΣ+ and | rEn | < | rEΞ0 |, whereas the magnetic radii have a pattern largely consistent with a naive expectation based on the dressed quark masses.
gamma* p ---> Delta form-factors in QCD
V. M. Belyaev; A. V. Radyushkin
1995-05-01
We use local quark-hadron duality to estimate the purely nonperturbative soft contribution to the {gamma}*p {yields} {Delta} form factors. Our results are in agreement with existing experimental data. We predict that the ratio G*{sub E}(Q{sup 2})/G*{sub M}(Q{sup 2}) is small for all accessible Q{sup 2}, in contrast to the perturbative QCD expectations that G*{sub E}(Q{sup 2}) {yields} -G*{sub M}(Q{sup 2}).
Nucleon strangeness form factors and moments of PDF
Doi, Takumi; Deka, Mridupawan; Dong, Shao-Jing; Draper, Terrence; Liu, Keh-Fei; Mankame, Devdatta; Mathur, Nilmani; Streuer, Thomas
2011-10-24
The calculation of the nucleon strangeness form factors from N{sub f} = 2+1 clover fermion lattice QCD is presented. Disconnected insertions are evaluated using the Z(4) stochastic method, along with unbiased subtractions from the hopping parameter expansion. We find that increasing the number of nucleon sources for each configuration improves the signal significantly. We obtain G{sub M}{sup s}(0) = -0.017(25)(07), which is consistent with experimental values, and has an order of magnitude smaller error. Preliminary results for the strangeness contribution to the second moment of the parton distribution function are also presented.
Two-photon exchange corrections to the pion form factor
Peter G. Blunden; Melnitchouk, Wally; Tjon, John A.
2010-01-06
Here, we compute two-photon exchange corrections to the electromagnetic form factor of the pion, taking into account the finite size of the pion. Compared to the soft-photon approximation for the infrared divergent contribution which neglects hadron structure effects, the corrections are found to be ≲ 1% for small Q^{2} (Q^{2} < 0.1 GeV^{2}), but increase to several percent for Q^{2} ≳ 1 GeV^{2} at extreme backward angles.
Minimal form factor digital-image sensor for endoscopic applications
NASA Astrophysics Data System (ADS)
Wäny, Martin; Voltz, Stephan; Gaspar, Fabio; Chen, Lei
2009-02-01
This paper presents a digital image sensor SOC featuring a total chip area (including dicing tolerances) of 0.34mm2 for endoscopic applications. Due to this extremely small form factor the sensor enables integration in endoscopes, guide wires and locater devices of less than 1mm outer diameter. The sensor embeds a pixel matrix of 10'000 pixels with a pitch of 3um x 3um covered with RGB filters in Bayer pattern. The sensor operates fully autonomous, controlled by an on chip ring oscillator and readout state machine, which controls integration AD conversion and data transmission, thus the sensor only requires 4 pin's for power supply and data communication. The sensor provides a frame rate of 40Frames per second over a LVDS serial data link. The endoscopic application requires that the sensor must work without any local power decoupling capacitances at the end of up to 2m cabling and be able to sustain data communication over the same wire length without deteriorating image quality. This has been achieved by implementation of a current mode successive approximation ADC and current steering LVDS data transmission. An band gap circuit with -40dB PSRR at the data frequency was implemented as on chip reference to improve robustness against power supply ringing due to the high series inductance of the long cables. The B&W versions of the sensor provides a conversion gain of 30DN/nJ/cm2 at 550nm with a read noise in dark of 1.2DN when operated at 2m cable. Using the photon transfer method according to EMVA1288 standard the full well capacity was determined to be 18ke-. According to our knowledge the presented work is the currently world smallest fully digital image sensor. The chip was designed along with a aspheric single surface lens to assemble on the chip without increasing the form factor. The extremely small form factor of the resulting camera permit's to provide visualization with much higher than state of the art spatial resolution in sub 1mm endoscopic
INTEGRATED SACHS-WOLFE EFFECT FOR GRAVITATIONAL RADIATION
Laguna, Pablo; Larson, Shane L.; Spergel, David; Yunes, Nicolas
2010-05-20
Gravitational waves (GWs) are messengers carrying valuable information about their sources. For sources at cosmological distances, the waves will also contain the imprint left by the intervening matter. The situation is in close analogy with cosmic microwave photons, for which the large-scale structures the photons traverse contribute to the observed temperature anisotropies, in a process known as the integrated Sachs-Wolfe effect. We derive the GW counterpart of this effect for waves propagating on a Friedman-Robertson-Walker background with scalar perturbations. We find that the phase, frequency, and amplitude of the GWs experience Sachs-Wolfe-type integrated effects, in addition to the magnification effects on the amplitude from gravitational lensing. We show that for supermassive black hole binaries, the integrated effects could account for measurable changes on the frequency, chirp mass, and luminosity distance of the binary, thus unveiling the presence of inhomogeneities, and potentially dark energy, in the universe.
ρ γ*→π (ρ ) transition form factors in the perturbative QCD factorization approach
NASA Astrophysics Data System (ADS)
Zhang, Ya-Lan; Cheng, Shan; Hua, Jun; Xiao, Zhen-Jun
2015-11-01
In this paper, we studied the ρ γ*→π and ρ γ*→ρ transition processes and made the calculations for the ρ π transition form factor Q4Fρ π(Q2) and the ρ -meson electromagnetic form factors, FLL ,LT ,TT(Q2) and F1 ,2 ,3(Q2), by employing the perturbative QCD (PQCD) factorization approach. For the ρ γ*→π transition, we found that the contribution to form factor Q4Fρ π(Q2) from the term proportional to the distribution amplitude combination ϕρT(x1)ϕπP(x2) is absolutely dominant, and the PQCD predictions for both the size and the Q2-dependence of this form factor Q4Fρ π(Q2) agree well with those from the extended anti-de Sitter/QCD models or the light-cone QCD sum rule. For the ρ γ*→ρ transition and in the region of Q2≥3 GeV2 , furthermore, we found that the PQCD predictions for the magnitude and their Q2-dependence of the F1(Q2) and F2(Q2) form factors agree well with those from the QCD sum rule, while the PQCD prediction for F3(Q2) is much larger than the one from the QCD sum rule.
Choroidal coloboma in a case of tay-sachs disease.
Ahmed, Nasreen Raees; Tripathy, Koushik; Kumar, Vivek; Gogia, Varun
2014-01-01
Coloboma as an ocular finding has been documented in various syndromes. Here we have a case of infantile Tay-Sachs disease associated with unilateral choroidal coloboma. To the best of our knowledge, such an association has not been documented in the literature. Whether such an association is a matter of chance or signifies the involvement of ganglioside metabolism in ocular embryogenesis remains to be elucidated. PMID:25295204
Distribution of a pseudodeficiency allele among Tay-Sachs carriers
Tomczak, J.; Grebner, E.E. ); Boogen, C. )
1993-08-01
Recently Triggs-Raine et al. (1992) identified a new mutation in the gene coding for the [alpha]-subunit of [beta]-hexosaminidase A (hex A), the enzyme whose deficiency causes Tay-Sachs disease. This mutation, a C[sub 739]-to-T transition in exon 7, results in an altered enzyme that is active (albeit at reduced levels) in cells but that has essentially no activity in serum. This so-called pseudodeficient allele was first detected in compound heterozygotes who also carried a Tay-Sachs disease allele and therefore had no detectable hex A in their serum but who were in good health. Carriers of this apparently benign mutation are generally indistinguishable from carriers of a lethal mutation by means of routine enzyme-based screening tests, because the product of the pseudodeficient allele is not detectable in serum and has decreased activity in cells. This suggests that some individuals who have been classified as Tay-Sachs carriers are actually carriers of the pseudodeficient allele and are not at risk to have a child affected with Tay-Sachs disease. The pseudodeficient allele may also be responsible for some inconclusive diagnoses, where leukocyte values fall below the normal range but are still above the carrier range. The fact that there are now two mutant alleles (the psuedodeficient and the adult) that are indistinguishable from the lethal infantile mutations by means of enzyme assay yet that are phenotypically very different and that together may account for as much as 12% of enzyme-defined carriers on the basis of the data here suggests that DNA analysis should be part of a comprehensive screening program. It will be particularly useful to identify the mutations in couples at risk, before they undergo prenatal diagnosis. DNA analysis will also resolve some inconclusive diagnoses.
Ricci inheritance collineations in Kantowski-Sachs spacetimes
NASA Astrophysics Data System (ADS)
Hussain, Tahir; Musharaf, Aisha; Khan, Suhail
2016-03-01
In this paper, we investigate Ricci Inheritance Collineations (RICs) in Kantowski-Sachs spacetimes. RICs are discussed in detail when Ricci tensor is degenerate and nondegenerate. In both the cases, RICs are obtained and it turns out that the dimension of Lie algebra of RICs is finite when Ricci tensor is nondegenerate. In the case when Ricci tensor is degenerate, we get finite as well as infinite dimensional group of RICs.
Choroidal Coloboma in a Case of Tay-Sachs Disease
Ahmed, Nasreen Raees; Kumar, Vivek; Gogia, Varun
2014-01-01
Coloboma as an ocular finding has been documented in various syndromes. Here we have a case of infantile Tay-Sachs disease associated with unilateral choroidal coloboma. To the best of our knowledge, such an association has not been documented in the literature. Whether such an association is a matter of chance or signifies the involvement of ganglioside metabolism in ocular embryogenesis remains to be elucidated. PMID:25295204
Kantowski-Sachs universes sourced by a Skyrme fluid
NASA Astrophysics Data System (ADS)
Parisi, Luca; Radicella, Ninfa; Vilasi, Gaetano
2015-03-01
The Kantowski-Sachs cosmological model sourced by a Skyrme field and a cosmological constant is considered in the framework of general relativity. Assuming a constant radial profile function α =π /2 for the hedgehog ansatz, the Skyrme contribution to Einstein equations is shown to be equivalent to an anisotropic fluid. Using dynamical system techniques, a qualitative analysis of the cosmological equations is presented. Physically interesting features of the model such as isotropization, bounce and recollapse are discussed.
a Study of Kantowski-Sachs Model in Ashtekar Variables
NASA Astrophysics Data System (ADS)
Chakraborty, Subenoy; Chakravarty, Nabajit
In this paper we study classical and quantum cosmology in Kantowski-Sachs model using Ashtekar variables. Classical solutions are obtained for the above model with a cosmological term and Hamilton-Jacobi (HJ) equations have been studied to obtain inflationary solutions. In quantum cosmology, the wave function of the Universe is obtained using path integral formalism as well as by solving the Wheeler-DeWitt (WD) equation.
Meson transition form factors in light-front holographic QCD
Brodsky, Stanley J.; Cao Fuguang; de Teramond, Guy F.
2011-10-01
We study the photon-to-meson transition form factors (TFFs) F{sub M}{gamma}(Q{sup 2}) for {gamma}{gamma}{sup *}{yields}M using light-front holographic methods. The Chern-Simons action, which is a natural form in five-dimensional anti-de Sitter (AdS) space, is required to describe the anomalous coupling of mesons to photons using holographic methods and leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the qq component of the pion wave function, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0}{yields}{gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the qq component of the pion wave function P{sub qq}=0.5 is required, thus giving indication that the contributions from higher Fock states in the pion light-front wave function need to be included in the analysis. The probability for the Fock state containing four quarks P{sub qqqq}{approx}10%, which follows from analyzing the hadron matrix elements for a dressed current model, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wave function. The results for the TFFs for the {eta} and {eta}{sup '} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{sup '} TFFs.
Measurement of the Neutral Weak Form Factors of the Proton
Deur, Alexandre; Fleck, Andre; Saha, Arunava; Gasparian, Ashot; Frois, Bernard; Wojtsekhowski, Bogdan; Vlahovic, Branislav; Perdrisat, Charles; Cavata, Christian; Jutier, Christophe; De Jager, Cornelis; Neyret, Damien; Dale, Daniel; Armstrong, David; Lhuillier, David; Prout, David; Margaziotis, Demetrius; Kim, Donghee; Burtin, Etienne; Chudakov, Eugene; Hersman, F.; Garibaldi, Franco; Marie, Frederic; Miller, Greg; Rutledge, Gary; Gerstner, George; Petratos, Gerassimos; Quemener, Gilles; Cates, Gordon; Thompson, J.; Martino, Jacques; Gomez, Javier; Jorda, Jean-Paul; Hansen, Jens-Ole; Chen, Jian-Ping; Jardillier, Johann; Calarco, John; LeRose, John; Price, John; Gao, Juncai; McIntyre, Justin; McCormick, Kathy; Fissum, Kevin; Kramer, Kevin; Aniol, Konrad; Kumar, Krishna; Wijesooriya, Krishni; Ewell, Lars; Todor, Luminita; Spradlin, Marcus; Jones, Mark; Leuschner, Mark; Epstein, Martin; Baylac, Maud; Holtrop, Maurik; Finn, Michael; Kuss, Michael; Kim, Min; Falletto, Nicolas; Liyanage, Nilanga; Glamazdin, Oleksandr; Rutt, Paul; Souder, Paul; Ulmer, Paul; Mastromarino, Peter; Djawotho, Pibero; Wilson, Richard; Suleiman, Riad; Holmes, Richard; Madey, Richard; Lourie, Robert; Michaels, Robert; Pomatsalyuk, Roman; Gilman, Ronald; Incerti, Sebastien; Escoffier, Stephanie; Pussieux, Thierry; Humensky, Thomas; Gorbenko, Viktor; Punjabi, Vina; Kahl, William; Meziani, Zein-Eddine
1999-02-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point [(Theta_{lab}) = 12.3r and (Q^{2}) = 0.48 (GeV/c)^{2}] is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G^{s}_{E}. The result, A = - 14.5 + or - 2.2 ppm, is consistent with the electroweak standard model and no additional contributions from strange quarks. In particular, the measurement implies G^{s}_{E} + 0.39G^{s}_{M} = 0.023 + or - 0.034(stat) + or - 0.022(syst) + or - 0.026(delta-G^{n}_{E}), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor.
Nucleon electromagnetic form factors in two-flavor QCD
NASA Astrophysics Data System (ADS)
Capitani, S.; Della Morte, M.; Djukanovic, D.; von Hippel, G.; Hua, J.; Jäger, B.; Knippschild, B.; Meyer, H. B.; Rae, T. D.; Wittig, H.
2015-09-01
We present results for the nucleon electromagnetic form factors, including the momentum transfer dependence and derived quantities (charge radii and magnetic moment). The analysis is performed using O (a ) improved Wilson fermions in Nf=2 QCD measured on the Coordinated Lattice Simulations ensembles. Particular focus is placed on a systematic evaluation of the influence of excited states in three-point correlation functions, which lead to a biased evaluation, if not accounted for correctly. We argue that the use of summed operator insertions and fit Ansätze including excited states allow us to suppress and control this effect. We employ a novel method to perform joint chiral and continuum extrapolations, by fitting the form factors directly to the expressions of covariant baryonic chiral effective field theory. The final results for the charge radii and magnetic moment from our lattice calculations include, for the first time, a full error budget. We find that our estimates are compatible with experimental results within their overall uncertainties.
Improved semileptonic form factor calculations in lattice QCD
Evans, Richard; Bali, Gunnar; Collins, Sara
2010-11-01
We investigate the computational efficiency of two stochastic based alternatives to the sequential propagator method used in lattice QCD calculations of heavy-light semileptonic form factors. In the first method, we replace the sequential propagator, which couples the calculation of two of the three propagators required for the calculation, with a stochastic propagator so that the calculations of all three propagators are independent. This method is more flexible than the sequential propagator method but introduces stochastic noise. We study the noise to determine when this method becomes competitive with the sequential propagator method, and find that for any practical calculation it is competitive with or superior to the sequential propagator method. We also examine a second stochastic method, the so-called 'one-end trick', concluding it is relatively inefficient in this context. The investigation is carried out on two gauge field ensembles, using the nonperturbatively improved Wilson-Sheikholeslami-Wohlert action with N{sub f}=2 mass-degenerate sea quarks. The two ensembles have similar lattice spacings but different sea-quark masses. We use the first stochastic method to extract O(a)-improved, matched lattice results for the semileptonic form factors on the ensemble with lighter sea quarks, extracting f{sub +}(0).
Small form factor optical fiber connector evaluation for harsh environments
NASA Astrophysics Data System (ADS)
Ott, Melanie N.; Thomes, W. Joe, Jr.; Chuska, Richard F.; Switzer, Robert; Blair, Diana E.
2011-09-01
For the past decade NASA programs have utilized the Diamond AVIM connector for optical fiber assemblies on space flight instrumentation. These connectors have been used in communications, sensing and LIDAR systems where repeatability and high performance are required. Recently Diamond has released a smaller form factor optical fiber connector called the "Mini-AVIM" which although more compact still includes the tight tolerances and the ratcheting feature of the heritage AVIM. NASA Goddard Space Flight Center Photonics Group in the Parts, Packaging and Assembly Technologies Office has been performing evaluations of this connector to determine how it compares to the performance of the AVIM connector and to assess its feasibility for harsh environmental applications. Vibration and thermal testing were performed on the Mini-AVIM with both multi-mode and single-mode optical fiber using insitu optical transmission monitoring. Random vibration testing was performed using typical launch condition profiles for most NASA missions but extended to 35 Grms, which is much higher than most requirements. Thermal testing was performed incrementally up to a range of -55°C to +125°C. The test results include both unjacketed fiber and cabled assembly evaluations. The data presented here indicate that the Mini-AVIM provides a viable option for small form factor applications that require a high performance optical fiber connector.
Measurement of the neutral weak form factors of the proton
Aniol, K.A.; Epstein, M.B.; Margaziotis, D.J.; Deur, A.; Spradlin, M.; Wilson, R.; Garibaldi, F.; Chen, J.; Chudakov, E.; de Jager, C.W.; Deur, A.; Gomez, J.; Hansen, O.; Kuss, M.; LeRose, J.; Michaels, R.; Price, J.S.; Rutt, P.M.; Saha, A.; Wojtsekhowski, B.; Madey, R.; Petratos, G.G.; Prout, D.; Suleiman, R.; Dale, D.; Glamazdin, A.; Gorbenko, V.; Pomatsalyuk, R.; Kim, D.H.; Kim, M.S.; Ewell, L.; Fissum, K.; Gao, J.; Liyanage, N.; Calarco, J.; Hersman, F.; Holtrop, M.; Leuschner, M.; Punjabi, V.; Vlahovic, B.; Jutier, C.; McCormick, K.; Todor, L.; Ulmer, P.E.; Cates, G.D.; Humensky, B.; Kumar, K.S.; Mastromarino, P.; Miller, G.W.; Spradlin, M.; Fleck, A.; Gilman, R.; McIntyre, J.; and others
1999-02-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point [{l_angle}{theta}{sub lab }{r_angle}=12.3{degree} and {l_angle}Q{sup 2}{r_angle}=0.48 (GeV /c){sup 2} ] is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G{sup s}{sub E} . The result, A={minus}14.5{plus_minus}2.2 ppm , is consistent with the electroweak standard model and no additional contributions from strange quarks. In particular, the measurement implies G{sup s}{sub E}+0.39G{sup s}{sub M}=0.023 {plus_minus}0.034(stat){plus_minus}0.022( syst){plus_minus}0.026({delta}G{sup n}{sub E}) , where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor. {copyright} {ital 1999} {ital The American Physical Society}
Electroweak form factors of the Δ (1232 ) resonance
NASA Astrophysics Data System (ADS)
Graczyk, Krzysztof M.; Żmuda, Jakub; Sobczyk, Jan T.
2014-11-01
Nucleon →Δ (1232 ) transition electroweak form factors are discussed in a single pion production model with nonresonant background terms originating from a chiral perturbation theory. Fits to electron-proton scattering F2 as well as neutrino scattering bubble chamber experimental data are performed. Both ν -proton and ν -neutron channel data are discussed in a unified statistical model. A new parametrization of the N →Δ (1232 ) vector form factors is proposed. In the case of model with deuteron nuclear effects fit to neutrino scattering data gives the axial mass MA Δ=0.85-0.08+0.09 GeV and C5A(0 )=1.10-0.14+0.15 in accordance with the Goldberger-Treiman relation. However, the consistency is spoiled when the deuteron effects are omitted; i.e., in this case the fit gives the axial mass MA Δ=0.8 1-0.09+0.09 GeV and C5A(0 )=0.9 3-0.13+0.13 .
Myerowitz, R. )
1988-06-01
Tay-Sachs disease is an inherited disorder in which the {alpha} chain of the lysosomal enzyme {beta}-N-acetylhexosaminidase A bears the mutation. Ashkenazi Jews are found to be carriers for a severe type of Tay-Sachs disease, the classic form, 10 times more frequently than the general population. Ashkenazi Jewish patients with classic Tay-Sachs disease have appeared to be clinically and biochemically identical, and the usual assumption has been that they harbor the same {alpha}-chain mutation. The author has isolated the {alpha}-chain gene from an Ashkenazi Jewish patient, GM2968, with classic Tay-Sachs disease and compared its nucleotide sequences with that of the normal {alpha}-chain gene in the promoter region, exon and splice junction regions, and polyadenylylation signal area. Only one difference was observed between these sequences. The alteration is presumed to be functionally significant and to result in aberrant mRNA splicing. Utilizing the polymerase chain reaction to amplify the region encompassing the mutation, the author developed an assay to screen patients and heterozygote carriers for this mutation. Surprisingly, in each of two Ashkenazi patients, only one {alpha}-chain allele harbored the splice junction mutation. Only one parent of each of these patients was positive for the defect. Another Ashkenazi patient did not bear this mutation at all nor did either of the subject's parents. The data are consistent with the presence of more than one mutation underlying the classic form of Tay-Sachs disease in the Ashkenazi Jewish population.
Thin and small form factor cells : simulated behavior.
Clews, Peggy Jane; Pluym, Tammy; Grubbs, Robert K.; Cruz-Campa, Jose Luis; Zubia, David; Young, Ralph Watson; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James
2010-07-01
Thin and small form factor cells have been researched lately by several research groups around the world due to possible lower assembly costs and reduced material consumption with higher efficiencies. Given the popularity of these devices, it is important to have detailed information about the behavior of these devices. Simulation of fabrication processes and device performance reveals some of the advantages and behavior of solar cells that are thin and small. Three main effects were studied: the effect of surface recombination on the optimum thickness, efficiency, and current density, the effect of contact distance on the efficiency for thin cells, and lastly the effect of surface recombination on the grams per Watt-peak. Results show that high efficiency can be obtained in thin devices if they are well-passivated and the distance between contacts is short. Furthermore, the ratio of grams per Watt-peak is greatly reduced as the device is thinned.
The Pion Charge Form Factor Through Pion Electroproduction
Horn, Tanja
2006-04-01
The goal of Jefferson Lab experiment E01-004 (F?-2) was the measurement of the longitudinal and transverse cross sections via pion electroproduction from hydrogen and deuterium for the purpose of extracting the charged pion form factor using pole dominance. The data were taken at two values of Q2 (1.60 and 2.45 GeV/c)2. In order to attain full coverage in R?, charged pions were detected in parallel kinematics (along the direction of momentum transfer, q), and at Â±3 degrees off the direction of momentum transfer. For each Q2 data were taken for two values of the virtual photon polarization, ?, respectively. All data were taken at a fixed center of mass energy, W=2.22 GeV. The longitudinal and transverse pieces of the cross section were separated using the Rosenbluth separation method.
Deuteron Electromagnetic Form Factors in AdS/QCD
NASA Astrophysics Data System (ADS)
Lyubovitskij, Valery E.; Gutsche, Thomas; Schmidt, Ivan; Vega, Alfredo
2016-07-01
We extend a soft-wall AdS/QCD approach to a description of deuteron properties. Our framework is based an effective action formulated in terms of AdS fields, which are holographically equivalent to the deuteron and photon fields. This action produces the equation of motion for the deuteron wave function and the Q^2-dependent electromagnetic current, which are then used to calculate the deuteron electromagnetic form factors and structure functions in the Euclidean region. We show that the predicted deuteron quantities are expressed through a universal function, which is defined by a single scale parameter κ and which has the correct 1/Q^{10} power scaling at large Q^2.
Finite-lattice form factors in free-fermion models
NASA Astrophysics Data System (ADS)
Iorgov, N.; Lisovyy, O.
2011-04-01
We consider the general {Z}_2 -symmetric free-fermion model on the finite periodic lattice, which includes as special cases the Ising model on the square and triangular lattices and the {Z}_n -symmetric BBS τ(2)-model with n = 2. Translating Kaufman's fermionic approach to diagonalization of Ising-like transfer matrices into the language of Grassmann integrals, we determine the transfer matrix eigenvectors and observe that they coincide with the eigenvectors of a square lattice Ising transfer matrix. This allows us to find exact finite-lattice form factors of spin operators for the statistical model and the associated finite-length quantum chains, of which the most general is equivalent to the XY chain in a transverse field.
Deuteron Electromagnetic Form Factors in AdS/QCD
NASA Astrophysics Data System (ADS)
Lyubovitskij, Valery E.; Gutsche, Thomas; Schmidt, Ivan; Vega, Alfredo
2016-03-01
We extend a soft-wall AdS/QCD approach to a description of deuteron properties. Our framework is based an effective action formulated in terms of AdS fields, which are holographically equivalent to the deuteron and photon fields. This action produces the equation of motion for the deuteron wave function and the Q^2 -dependent electromagnetic current, which are then used to calculate the deuteron electromagnetic form factors and structure functions in the Euclidean region. We show that the predicted deuteron quantities are expressed through a universal function, which is defined by a single scale parameter κ and which has the correct 1/Q^{10} power scaling at large Q^2.
Chiral corrections to the hyperon vector form factors
NASA Astrophysics Data System (ADS)
Villadoro, Giovanni
2006-07-01
We present a complete calculation of the SU(3)-breaking corrections to the hyperon vector form factors up to O(p4) in heavy baryon chiral perturbation theory. Because of the Ademollo-Gatto theorem, at this order the results do not depend on unknown low energy constants and allow to test the convergence of the chiral expansion. We complete and correct previous calculations and find that O(p3) and O(1/M0) corrections are important. We also study the inclusion of the decuplet degrees of freedom, showing that in this case the perturbative expansion is jeopardized. These results raise doubts on the reliability of the chiral expansion for hyperons.
Longitudinal electron scattering form factors for 54,56Fe
NASA Astrophysics Data System (ADS)
Salman, A. D.; Kadhim, D. R.
2014-09-01
In this paper, inelastic longitudinal electron scattering form factors for C2 transition have been studied in 54Fe and 56Fe with the aid of shell model calculations. The GX1 effective interaction for the fp-shell is used with the nucleon-nucleon realistic interaction Michigan three-range Yukawa and Modified surface delta interaction as a two-body interactions. The core polarization effects is taken into account through the first-order perturbation theory with the effective charge, which is taken to the proton and the neutron. The effective charge along with the core effects up to 6 ℏw enhanced the calculation very well and improving good agreement with the experimental data.
Lattice calculation of composite dark matter form factors
NASA Astrophysics Data System (ADS)
Appelquist, T.; Brower, R. C.; Buchoff, M. I.; Cheng, M.; Cohen, S. D.; Fleming, G. T.; Kiskis, J.; Lin, M. F.; Neil, E. T.; Osborn, J. C.; Rebbi, C.; Schaich, D.; Schroeder, C.; Syritsyn, S.; Voronov, G.; Vranas, P.; Wasem, J.
2013-07-01
Composite dark matter candidates, which can arise from new strongly-coupled sectors, are well-motivated and phenomenologically interesting, particularly in the context of asymmetric generation of the relic density. In this work, we employ lattice calculations to study the electromagnetic form factors of electroweak-neutral dark-matter baryons for a three-color, QCD-like theory with Nf=2 and 6 degenerate fermions in the fundamental representation. We calculate the (connected) charge radius and anomalous magnetic moment, both of which can play a significant role for direct detection of composite dark matter. We find minimal Nf dependence in these quantities. We generate mass-dependent cross sections for dark matter-nucleon interactions and use them in conjunction with experimental results from XENON100, excluding dark matter candidates of this type with masses below 10 TeV.
Baryon Transition Form Factors at JLab: Status and Outlook
Ralf Gothe
2009-12-01
The measurements of exclusive single-meson and double-pion electro-production cross sections off the proton to study nucleon resonances will be extended to higher momentum transfers with the CLAS12 detector and the energy upgraded CEBAF beam. Based on new theoretical developments to extract and interpret the electromagnetic transition form factors and on the experience gained from the most recent results, the newly formed collaboration of experimentalists and theorists shall enable us to provide unprecedented high-precision data, high-quality analyses, and state-of-the-art model and QCD based calculations in a Q domain up to 10 GeV{sup 2}. For the first time nucleon resonance structures will be studied at still unexplored distance scales, where the dressed quark contributions are the dominating degrees of freedom and their strong interaction is responsible for the ground and excited nucleon state formation. These studies also open up a promising opportunity to understand the origin of more than 98% of the nucleon mass that is created by strong fields predominantly at these distance scales by dressing the current quarks.
Factors Governing Surface Form Accuracy In Diamond Machined Components
NASA Astrophysics Data System (ADS)
Myler, J. K.; Page, D. A.
1988-10-01
simple spheres. It is important however to realise that a diamond turning process will possess a new set of criteria which limit the accuracy of the surface profile created corresponding to a completely new set of specifications. The most important factors are:- tool centring accuracy, surface waviness, conical form error, and other rotationally symmetric non spherical errors. The fixturing of the workpiece is very different from that of a conventional lap, since in many cases the diamond machine resembles a conventional lathe geometry where the workpiece rotates at a few thousand R.P.M. Substrates must be held rigidly for rotation at such speeds as compared with more delicate mounting methods for conventional laps. Consequently the workpiece may suffer from other forms of deformation which are non-rotationally symmetric due to mounting stresses (static deformation) and stresses induced at the speed of rotation (dynamic deformation). The magnitude of each of these contributions to overall form error will be a function of the type of machine, the material, substrate, and testing design. The following sections describe each of these effects in more detail based on experience obtained on a Pneumo Precision MSG325 XY CNC machine. Certain in-process measurement techniques have been devised to minimise and quantify each contribution.
The white matter of the human cerebrum: Part I The occipital lobe by Heinrich Sachs
Forkel, Stephanie J.; Mahmood, Sajedha; Vergani, Francesco; Catani, Marco
2015-01-01
This is the first complete translation of Heinrich Sachs' outstanding white matter atlas dedicated to the occipital lobe. This work is accompanied by a prologue by Prof Carl Wernicke who for many years was Sachs' mentor in Breslau and enthusiastically supported his work. PMID:25527430
Phenomenological dynamics of loop quantum cosmology in Kantowski-Sachs spacetime
Chiou, D.-W.
2008-08-15
The fundamental theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this paper investigates the cosmological model of Kantowski-Sachs spacetime with a free massless scalar field at the level of phenomenological dynamics with the LQC discreteness corrections. The LQC corrections are implemented in two different improved quantization schemes. In both schemes, the big bang and big crunch singularities of the classical solution are resolved and replaced by the big bounces when the area or volume scale factor approaches the critical values in the Planck regime measured by the reference of the scalar field momentum. Symmetries of scaling are also noted and suggest that the fundamental spatial scale (area gap) may give rise to a temporal scale. The bouncing scenarios are in an analogous fashion of the Bianchi I model, naturally extending the observations obtained previously.
Quaternions, Torsion and the Physical Vacuum: Theories of M. Sachs and G. Shipov Compared
NASA Astrophysics Data System (ADS)
Cyganski, David; Page, William S.
Of several developments of unified field theories in the spirit of Einstein's original objective of a fully geometric description of all classical fields as well as quantum mechanics, two are particularly noteworthy. The works of Mendel Sachs and Gennady Shipov stand apart as major life works comprising tens of papers, several monographs and decades of effort. Direct comparison of these theories is hampered however by differences in notation and conceptual view-point. Despite these differences, there are many parallels between the fundamental mathematical structures appearing in each. In this paper we discuss the main tenets of the two approaches and demonstrate that they both give rise to a factorization of the invariant interval of general relativity.
Sialidase-mediated depletion of GM2 ganglioside in Tay-Sachs neuroglia cells.
Igdoura, S A; Mertineit, C; Trasler, J M; Gravel, R A
1999-06-01
Tay-Sachs disease is a severe, inherited disease of the nervous system caused by accumulation of the brain lipid GM2 ganglioside. Mouse models of Tay-Sachs disease have revealed a metabolic bypass of the genetic defect based on the more potent activity of the enzyme sialidase towards GM2. To determine whether increasing the level of sialidase would produce a similar effect in human Tay-Sachs cells, we introduced a human sialidase cDNA into neuroglia cells derived from a Tay-Sachs fetus and demonstrated a dramatic reduction in the accumulated GM2. This outcome confirmed the reversibility of GM2 accumulation and opens the way to pharmacological induction or activation of sialidase for the treatment of human Tay-Sachs disease. PMID:10332044
Nucleon form factors and hidden symmetry in holographic QCD
Hong, Deog Ki; Rho, Mannque; Yee, Ho-Ung; Yi, Piljin
2008-01-01
The vector dominance of the electromagnetic form factors both for mesons and baryons arises naturally in holographic QCD, where both the number of colors and the 't Hooft coupling are taken to be very large, offering a bona-fide derivation of the notion of vector dominance. The crucial ingredient for this is the infinite tower of vector mesons in the approximations made which share features that are characteristic of the quenched approximation in lattice QCD. We approximate the infinite sum by contributions from the lowest four vector mesons of the tower which turn out to saturate the charge and magnetic moment sum rules within a few percent and compute them totally free of unknown parameters for momentum transfers Q{sup 2} < or approx. 1 GeV{sup 2}. We identify certain observables that can be reliably computed within the approximations and others that are not, and discuss how the improvement of the latter can enable one to bring holographic QCD closer to QCD proper.
A nursing challenge: adult-onset Tay-Sachs disease.
Hamilton, D
1991-12-01
Adult-onset GM2 gangliosidosis (AOG), also labelled Adult-Onset Tay-Sachs disease, is a slowly progressing disease caused by a gradual accumulation of the GM2 ganglioside in neurons due to defective hexosaminidase A. Recent research findings and clinical experiences suggest that AOG may be more widespread than previously believed. Moreover, the diagnosis of AOG is often delayed because patients present with psychotic symptoms that mimic dementia, schizophrenia, mania, and depression. Because AOG patients typically respond poorly to psychiatric drug therapy and the symptomatology is so diverse, nurses must design and implement nursing care that ensures safety, structure, and comfort. PMID:1759864
Nucleon Structure and hyperon form factors from lattice QCD
Lin, Huey-Wen
2007-06-11
In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point to be 1.23(5), consistant with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(26), consistent with the Adelaide-JLab Collaboration's result. The hyperon Sigma and Xi axial coupling constants are also performed for the first time in a lattice calculation, g_SigmaSigma = 0.441(14) and g_XiXi = -0.277(11).
Nucleon Structure and Hyperon Form Factors from Lattice QCD.
Lin,H.W.
2007-06-11
In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point. to be 1.23(5), consistent with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(2G), consistent with the Adelaide-JLab Collaboration's result. The hyperon {Sigma} and {Xi} axial coupling constants are also performed for the first time in a lattice calculation, g{sub {Sigma}{Sigma}} = 0.441(14) and g{sub {Xi}{Xi}} = -0.277(11).
A human factors approach to waste form design
Rodriguez, M.A.
1994-04-01
The current study consist of two experiments and an example of a revised waste form to demonstrate the necessity of careful form design and provide guidance in obtaining accurate information through written solicitation of any kind. In Experiment 1, two differently designed forms were used to solicit the same list of specific information. The data suggest that the more clearly designed form significantly produced more of the specific information required than the form that just listed the questions. Experiment 2, which is to be conducted during the spring semester 1994, is designed to address three specific aspects of form design. The results of this Experiment 2 will be interpreted and presented at the 1994 International High-Level Radioactive Waste Management Conference, May 22--26. Guidelines and examples of form design are given.
Next-to-leading-order correction to pion form factor in k{sub T} factorization
Li Hsiangnan; Shen Yuelong; Wang Yuming; Zou Hao
2011-03-01
We calculate the next-to-leading-order (NLO) correction to the pion electromagnetic form factor at leading twist in the k{sub T} factorization theorem. Partons off-shell by k{sub T}{sup 2} are considered in both quark diagrams and effective diagrams for the transverse-momentum-dependent pion wave function. The light-cone singularities in the transverse-momentum-dependent pion wave function are regularized by rotating the Wilson lines away from the light cone. The soft divergences from gluon exchanges among initial- and fal-state partons cancel exactly. We derive the infrared-finite k{sub T}-dependent NLO hard kernel for the pion electromagnetic form factor by taking the difference of the above two sets of diagrams. Varying the renormalization and factorization scales, we find that the NLO correction is smaller, when both the scales are set to the invariant masses of internal particles: it becomes lower than 40% of the leading-order contribution for momentum transfer squared Q{sup 2}>7 GeV{sup 2}. It is observed that the NLO leading-twist correction does not play an essential role in explaining the experimental data, but the leading-order higher-twist contribution does.
Integrated Sachs-Wolfe effect in interacting dark energy models
Olivares, German; Pavon, Diego; Atrio-Barandela, Fernando
2008-05-15
Models with dark energy decaying into dark matter have been proposed in cosmology to solve the coincidence problem. We study the effect of such coupling on the cosmic microwave background temperature anisotropies. The interaction changes the rate of evolution of the metric potentials and the growth rate of matter density perturbations and modifies the integrated Sachs-Wolfe component of cosmic microwave background temperature anisotropies, enhancing the effect. Cross correlation of galaxy catalogs with cosmic microwave background maps provides a model-independent test to constrain the interaction. We particularize our analysis for a specific interacting model and show that galaxy catalogs with median redshifts z{sub m}=0.1-0.9 can rule out models with an interaction parameter strength of c{sup 2}{approx_equal}0.1 better than 99.95% confidence level. Values of c{sup 2}{<=}0.01 are compatible with the data and may account for the possible discrepancy between the fraction of dark energy derived from Wilkinson microwave anisotropy probe 3 yr data and the fraction obtained from the integrated Sachs-Wolfe effect. Measuring the fraction of dark energy by these two methods could provide evidence of an interaction.
NASA Astrophysics Data System (ADS)
Rezaei, B.; Dashtimoghadam, A.
2014-09-01
The basic properties and form factors of the deuteron system are investigated for the different forms of the Wood-Saxon potential. We have used the Nikiforov-Uvarov (NU) method for analytical solution of the radial Schrodinger equation. A comparison of the calculated values with experimental results are given. It is shown that the obtained results for the modified form of the Wood-Saxon potential are very close to the experimental results in comparison with other forms of the potential.
Structural consequences of amino acid substitutions causing Tay-Sachs disease.
Ohno, Kazuki; Saito, Seiji; Sugawara, Kanako; Sakuraba, Hitoshi
2008-08-01
To determine the structural changes in the alpha-subunit of beta-hexosaminidase due to amino acid substitutions causing Tay-Sachs disease, we built structural models of mutant alpha-subunits resulting from 33 missense mutations (24 infantile and 9 late-onset), and analyzed the influence of each amino acid replacement on the structure by calculating the number of atoms affected and determining the solvent-accessible surface area of the corresponding amino acid residue in the wild-type alpha-subunit. In the infantile Tay-Sachs group, the number of atoms influenced by a mutation was generally larger than that in the late-onset Tay-Sachs group in both the main chain and the side chain, and residues associated with the mutations found in the infantile Tay-Sachs group tended to be less solvent-accessible than those in the late-onset Tay-Sachs group. Furthermore, color imaging determined the distribution and degree of the structural changes caused by representative amino acid substitutions, and that there were also differences between the infantile and late-onset Tay-Sachs disease groups. Structural study is useful for elucidating the basis of Tay-Sachs disease. PMID:18490185
Pion form factor using domain wall valence quarks and asqtad sea quarks
George Fleming; Frederic Bonnet; Robert Edwards; Randal Lewis; David Richards
2004-09-01
We compute the pion electromagnetic form factor in a hybrid calculation with domain wall valence quarks and improved staggered (asqtad) sea quarks. This method can easily be extended to rho-to-gamma-pi transition form factors.
'Cherry red spot' in a patient with Tay-Sachs disease: case report.
Aragão, Ricardo Evangelista Marrocos de; Ramos, Régia Maria Gondim; Pereira, Felipe Bezerra Alves; Bezerra, Andreya Ferreira Rodrigues; Fernandes, Daniel Nogueira
2009-01-01
Tay-Sachs disease is an autosomal recessive disorder of sphingolipid metabolism, caused by enzyme hexosaminidase A deficiency that leads to an accumulation of GM2 in neurocytes which results in progressive loss of neurological function. The accumulation of lipid in retinal ganglion cells that leads to a chalk-white appearance of the fundus called 'cherry red spot' is the hallmark of Tay-Sachs disease. It is also seen in others neurometabolic diseases as well as in central retinal artery occlusion. This case reports a child with Tay-Sachs disease in a family with four previous similar deaths without diagnostic. PMID:19820796
Iso-vector form factors of the delta and nucleon in QCD sum rules
Ozpineci, A.
2012-10-23
Form factors are important non-perturbative properties of hadrons. They give information about the internal structure of the hadrons. In this work, iso-vector axial-vector and iso-vector tensor form factors of the nucleon and the iso-vector axial-vector {Delta}{yields}N transition form factor calculations in QCD Sum Rules are presented.
Richard, M.; Triggs-Raine, B.; Natowicz, M.
1994-09-01
Tay-Sachs disease is an autosomal recessive lysosomal storage disorder resulting from mutations in the HEXA gene that cause a deficiency in the activity of that enzyme {beta}-hexosaminidase A (Hex A). This deficiency leads to the build-up of G{sub M2} ganglioside, resulting in neurodegeneration and death. Biochemical analysis of a non-Jewish patient with a late-infantile form of Tay-Sachs disease revealed a substantial level of Hex A activity (38.4%) when 4-MUG was used as the substrate. However, when a substrate (4-MUGS) specific for the {alpha}-subunit of Hex A ({alpha}{beta}) was used, almost no activity was detected in the HEXA gene of the patient using SSCP analysis followed by sequencing. The first mutation, a G533A substitution in exon 5, is previously described and associated with the B1 form of Tay-Sachs disease. The second mutation is a novel a-to-g base change at the +3 position of intron 8. This was confirmed using the AIRS method, whereby a MaeIII site was created in the presence of the mutation. Normal and patient mRNA was reverse transcribed and exons 7 to 9 were PCR-amplified from the cDNA. An abnormally sized amplification product detected only in the patient cDNA was sequenced; exon 8 had been deleted and exons 7 and 9 were spliced together. A substantial level of normally-sized PCR product was also detected in the patient`s cDNA. Experiments are in progress to determine if this is produced from the allele harboring the G533A mutation. Given that previous mutations of this type have been associated with 97-100% abnormal splicing, this mutation is likely to be the cause, together with the G533A mutation, of Tay-Sachs disease in this patient.
Box products in nilpotent normal form theory: The factoring method
NASA Astrophysics Data System (ADS)
Murdock, James
2016-01-01
Let N be a nilpotent matrix and consider vector fields x ˙ = Nx + v (x) in normal form. Then v is equivariant under the flow eN*t for the inner product normal form or eMt for the sl2 normal form. These vector equivariants can be found by finding the scalar invariants for the Jordan blocks in N* or M; taking the box product of these to obtain the invariants for N* or M itself; and then boosting the invariants to equivariants by another box product. These methods, developed by Murdock and Sanders in 2007, are here given a self-contained exposition with new foundations and new algorithms yielding improved (simpler) Stanley decompositions for the invariants and equivariants. Ideas used include transvectants (from classical invariant theory), Stanley decompositions (from commutative algebra), and integer cones (from integer programming). This approach can be extended to covariants of sl2k for k > 1, known as SLOCC in quantum computing.
Bound Nucleon Form Factors, Quark-Hadron Duality, and the Nuclear EMC Effect
K. Tsushima; D.H. Lu; W. Melnitchouk; K. Saito; A.W. Thomas
2002-09-13
We discuss the electromagnetic form factors, axial form factors, and structure functions of a nucleon bound in the quark-meson coupling (QMC) model. Free space nucleon form factors are calculated using the improved cloudy bag model (ICBM). After describing finite nuclei and nuclear matter in the quark-based (EMC) model, the in-medium modification of the bound nucleon form factors is calculated in the same model. Finally, the bound nucleon structure function, F2, is extracted using the calculated in-medium electromagnetic form factors and Bloom-Gilman (quark-hadron) duality.
Tay-Sachs disease: current perspectives from Australia.
Lew, Raelia M; Burnett, Leslie; Proos, Anné L; Delatycki, Martin B
2015-01-01
Tay-Sachs disease (TSD) is a fatal, recessively inherited neurodegenerative condition of infancy and early childhood. Although rare in most other populations, the carrier frequency is one in 25 in Ashkenazi Jews. Australian high-school-based TSD preconception genetic screening programs aim to screen, educate, and optimize reproductive choice for participants. These programs have demonstrated high uptake, low psychological morbidity, and have been shown to result in fewer than expected Jewish TSD-affected births over 18 years of operation. The majority of Jewish individuals of reproductive age outside of the high school screening program setting in Australia have not accessed screening. Recent recommendations advocate supplementing the community high school screening programs with general practitioner- and obstetrician-led genetic screening of Ashkenazi Jewish individuals for TSD and other severe recessive diseases for which this group is at risk. Massively parallel DNA sequencing is expected to become the testing modality of choice over the coming years. PMID:25653550
INTEGRATED SACHS-WOLFE IMPRINT OF SUPERSTRUCTURES ON LINEAR SCALES
Papai, Peter; Szapudi, Istvan; Granett, Benjamin R.
2011-05-01
We build a model for the density and integrated Sachs-Wolfe (ISW) profile of supervoid and supercluster structures. Our model assumes that fluctuations evolve linearly from an initial Gaussian random field. We find these assumptions capable of describing N-body simulations and simulated ISW maps remarkably well on large scales. We construct an ISW map based on locations of superstructures identified previously in the Sloan Digital Sky Survey Luminous Red Galaxy sample. A matched filter analysis of the cosmic microwave background confirms a signal at the 3.2{sigma} confidence level and estimates the radius of the underlying structures to be 55 {+-} 28 h{sup -1} Mpc. The amplitude of the signal, however, is 2{sigma} higher than {Lambda}CDM predictions.
ATYPICAL PRESENTATION OF LATE-ONSET TAY-SACHS DISEASE
DEIK, ANDRES; SAUNDERS-PULLMAN, RACHEL
2015-01-01
Introduction Late-onset Tay-Sachs disease (LOTS) is a lysosomal storage disease caused by deficient Beta-hexosaminidase A activity. Methods We describe a 53-year-old woman who presented with adult-onset leg weakness, and whose initial diagnosis was progressive muscular atrophy without identifiable etiology. Development of cerebellar ataxia in mid-life prompted reassessment. Results Beta-hexosaminidase A quantification assay demonstrated absence of the isozyme. Genetic testing identified compound heterozygous mutations in the HEXA gene, confirming the diagnosis of LOTS. Conclusions The phenotypic spectrum of LOTS includes motor neuronopathy, ataxia, choreoathetosis, neuropathy, and psychiatric symptoms in various combinations. This patient highlights the emergence of different clinical features over many years and emphasizes the need to consider LOTS in the differential diagnosis of progressive muscular atrophy. PMID:24327357
Tay-Sachs disease: current perspectives from Australia
Lew, Raelia M; Burnett, Leslie; Proos, Anné L; Delatycki, Martin B
2015-01-01
Tay-Sachs disease (TSD) is a fatal, recessively inherited neurodegenerative condition of infancy and early childhood. Although rare in most other populations, the carrier frequency is one in 25 in Ashkenazi Jews. Australian high-school-based TSD preconception genetic screening programs aim to screen, educate, and optimize reproductive choice for participants. These programs have demonstrated high uptake, low psychological morbidity, and have been shown to result in fewer than expected Jewish TSD-affected births over 18 years of operation. The majority of Jewish individuals of reproductive age outside of the high school screening program setting in Australia have not accessed screening. Recent recommendations advocate supplementing the community high school screening programs with general practitioner- and obstetrician-led genetic screening of Ashkenazi Jewish individuals for TSD and other severe recessive diseases for which this group is at risk. Massively parallel DNA sequencing is expected to become the testing modality of choice over the coming years. PMID:25653550
[Physician satire and patient scorn in Hans Sachs' old Nürnberg and the physicians].
Sauerbeck, K O
1993-01-01
Among the best poems of Hans Sachs quite a few describe patient-physician relationships in 16th century Nuremberg. These poems offer a vivid impression of the technical aspects as well as of the social context of medical treatment at the time. Hans Sachs ridiculed the doctors and their patients, implying that everybody attempted to cheat the other side, and he provides evidence of a great influence of charlatans on the country population. The poems of Hans Sachs are extraordinary pieces or art; their aesthetics, though, appear unusual to us today. Medical satire is part of all European cultures, and has been written throughout medical history. Most motives of later satires focussing on physicians may be traced to Hans Sachs' poetry. PMID:8310473
Tomita, Kenji
2010-03-15
On the basis of the Gerlach-Sengupta theory of gauge-invariant perturbations, a formula of the integrated Sachs-Wolfe effect for a central observer is derived on general spherically symmetric spacetimes. It will be useful for comparative studies of theoretical and observational aspects of the integrated Sachs-Wolfe effect in the Lemaitre-Tolman-Bondi cosmological models which have been noticed by explaining the apparent acceleration without cosmological constant.
Tay-Sach disease with "cherry-red spot"--first reported case in Malaysia.
Chan, L Y; Balasubramaniam, S; Sunder, R; Jamalia, R; Karunakar, T V N; Alagaratnam, J
2011-12-01
We present a rare case of Tay-Sachs disease with retinal 'cherry-red spots' in a 19-month-old Malay child. Molecular genetic studies confirmed the diagnosis. The case highlights that 'cherry-red spot' is a useful clinical clue in Tay-Sachs disease and several other lysosomal storage disorders. It serves as an ideal illustration of the eye as a window to inborn error of metabolism. PMID:22390110
Chiral perturbation theory and off-shell electromagnetic form factors
Rudy, T.E.; Fearing, H.W.; Scherer, S.
1995-05-10
The off-shell electromagnetic vertex of pions and kaons is calculated to {ital O}({ital p}{sup 4}) in the momentum expansion within the framework of chiral perturbation theory to one loop. The formalism of Gasser and Leutwyler is extended to accommodate the most general form for off-shell Green`s functions in the pseudoscalar meson sector. To that end we identify the structures at {ital O}({ital p}{sup 4}) which were initially removed by using the equation of motion of the lowest-order lagrangian. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
Mark, Brian L.; Mahuran, Don J.; Cherney, Maia M.; Zhao, Dalian; Knapp, Spencer; James, Michael N.G.
2010-12-01
In humans, two major {beta}-hexosaminidase isoenzymes exist: Hex A and Hex B. Hex A is a heterodimer of subunits {alpha} and {beta} (60% identity), whereas Hex B is a homodimer of {beta}-subunits. Interest in human {beta}-hexosaminidase stems from its association with Tay-Sachs and Sandhoff disease; these are prototypical lysosomal storage disorders resulting from the abnormal accumulation of G{sub M2}-ganglioside (G{sub M2}). Hex A degrades G{sub M2} by removing a terminal N-acetyl-D-galactosamine ({beta}-GalNAc) residue, and this activity requires the G{sub M2}-activator, a protein which solubilizes the ganglioside for presentation to Hex A. We present here the crystal structure of human Hex B, alone (2.4 {angstrom}) and in complex with the mechanistic inhibitors GalNAc-isofagomine (2.2 {angstrom}) or NAG-thiazoline (2.5 {angstrom}). From these, and the known X-ray structure of the G{sub M2}-activator, we have modeled Hex A in complex with the activator and ganglioside. Together, our crystallographic and modeling data demonstrate how {alpha} and {beta}-subunits dimerize to form either Hex A or Hex B, how these isoenzymes hydrolyze diverse substrates, and how many documented point mutations cause Sandhoff disease ({beta}-subunit mutations) and Tay-Sachs disease ({alpha}-subunit mutations).
Nucleon tensor form factors induced by isovector and isoscalar currents in QCD
Aliev, T. M.; Savci, M.; Azizi, K.
2011-10-01
Using the most general form of the nucleon interpolating current, we calculate the tensor form factors of the nucleon within light cone QCD sum rules. A comparison of our results on tensor form factors with those of the chiral-soliton model and lattice QCD is given.
Resource Form Factor and Installation of GFA Controllers
DeSteese, John G.; Hammerstrom, Donald J.
2009-11-15
The focus of this task is to optimize the form and placement of a controller comprising the Grid Friendly™ appliance (GFA) controller, power supply and power relay (and/or a solid-state power electronic switch) that would command a domestic water heater to shed its load in response to stress on the electric power grid. The GFA controller would disconnect the water heater from its supply circuit whenever it senses a low voltage signal or other indicators of system stress communicated via the electric power distribution system. Power would be reconnected to the appliance when the GFA controller senses the absence of these signals. This project has also considered more frequent cycling of this controller’s relay switch to perform demand-side frequency regulation. The principal criteria considered in this optimization are reliability, cost and life expectancy of the GFA components. The alternative embodiments of the GFA equipment under consideration are: Option 1- installation inside the insulation space of the water heater between the tank and jacket Option 2 containment in a separate nearby electrical enclosure Option 3 - as a modification or adjunct to the distribution panel housing and/or the breaker that protects the water heater supply circuit.
Highly Efficient Small Form Factor LED Retrofit Lamp
Steven Allen; Fred Palmer; Ming Li
2011-09-11
This report summarizes work to develop a high efficiency LED-based MR16 lamp downlight at OSRAM SYLVANIA under US Department of Energy contract DE-EE0000611. A new multichip LED package, electronic driver, and reflector optic were developed for these lamps. At steady-state, the lamp luminous flux was 409 lumens (lm), luminous efficacy of 87 lumens per watt (LPW), CRI (Ra) of 87, and R9 of 85 at a correlated color temperature (CCT) of 3285K. The LED alone achieved 120 lumens per watt efficacy and 600 lumen flux output at 25 C. The driver had 90% electrical conversion efficiency while maintaining excellent power quality with power factor >0.90 at a power of only 5 watts. Compared to similar existing MR16 lamps using LED sources, these lamps had much higher efficacy and color quality. The objective of this work was to demonstrate a LED-based MR16 retrofit lamp for replacement of 35W halogen MR16 lamps having (1) luminous flux of 500 lumens, (2) luminous efficacy of 100 lumens per watt, (3) beam angle less than 40{sup o} and center beam candlepower of at least 1000 candelas, and (4) excellent color quality.
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
Code of Federal Regulations, 2010 CFR
2010-10-01
... of Transportation Cost Factors. 247.372 Section 247.372 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors....
Up- and Down-Quark Contributions to the Nucleon Form Factors
NASA Astrophysics Data System (ADS)
Qattan, I. A.; Arrington, J.
2014-03-01
Recent measurements of the neutron s electric to magnetic form factors ratio, Rn = µnGnE/GnM, up to 3.4 (GeV/c)2 combined with existing Rp = µpGpE/GpM measurements in the same Q2 range allowed, for the first time, a separation of the up- and downquark contributions to the form factors at high Q2, as presented by Cates, et al.. Our analysis expands on the original work by including additional form factor data, applying two-photon exchange (TPE) corrections, and accounting for the uncertainties associated with all of the form factor measurements.
On soft theorems and form factors in N=4 SYM theory
NASA Astrophysics Data System (ADS)
Bork, L. V.; Onishchenko, A. I.
2015-12-01
Soft theorems for the form factors of 1/2-BPS and Konishi operator super-multiplets are derived at tree level in N=4 SYM theory. They have a form identical to the one in the amplitude case. For MHV sectors of stress tensor and Konishi operator supermultiplets loop corrections to soft theorems are considered at one loop level. They also appear to have universal form in the soft limit. Possible generalization of the on-shell diagrams to the form factors based on leading soft behavior is suggested. Finally, we give some comments on inverse soft limit and integrability of form factors in the limit q 2 → 0.
Factor Structure and Construct Validity of the Counselor Skills Personal Development Rating Form.
ERIC Educational Resources Information Center
Torres-Rivera, Edil; Wilbur, Michael P.; Maddux, Cleborne D.; Smaby, Marlowe H.; Phan, Loan T.; Roberts-Wilbur, Janice
2002-01-01
Presents an exploratory factor analysis of the scores of 248 counselors-in-training on the Counselor Skills Personal Development Rating Form (CSPD-RF). Authors of the test hypothesized that the CPSD-RF measured 2 factors, personal development and skills development. Factor analysis revealed 4 factors accounting for 58.4% of the total variance,…
Flavor decomposition of the nucleon electromagnetic form factors at low Q2
NASA Astrophysics Data System (ADS)
Qattan, I. A.; Arrington, J.; Alsaad, A.
2015-06-01
Background: The spatial distribution of charge and magnetization within the proton is encoded in the elastic form factors. These have been precisely measured in elastic electron scattering, and the combination of proton and neutron form factors allows for the separation of the up- and down-quark contributions. Purpose: In this work, we extract the proton and neutron form factors from worldwide data with an emphasis on precise new data covering the low-momentum region, which is sensitive to the large-scale structure of the nucleon. From these, we separate the up- and down-quark contributions to the proton form factors. Method: We combine cross section and polarization measurements of elastic electron-proton scattering to separate the proton form factors and two-photon exchange (TPE) contributions. We combine the proton form factors with parametrization of the neutron form factor data and uncertainties to separate the up- and down-quark contributions to the proton's charge and magnetic form factors. Results: The extracted TPE corrections are compared to previous phenomenological extractions, TPE calculations, and direct measurements from the comparison of electron and positron scattering. The flavor-separated form factors are extracted and compared to models of the nucleon structure. Conclusions: With the inclusion of the precise new data, the extracted TPE contributions show a clear change of sign at low Q2, which is necessary to explain the high-Q2 form factor discrepancy while being consistent with the known Q2→0 limit. We find that the new Mainz data yield a significantly different result for the proton magnetic form factor and its flavor-separated contributions. We also observe that the rms radius of both the up- and down-quark distributions are smaller than the rms charge radius of the proton.
Integrated Sachs-Wolfe effect in time varying vacuum model
Wang, Y. T.; Gui, Y. X.; Xu, L. X.; Lu, J. B.
2010-04-15
The integrated Sachs-Wolfe (ISW) effect is an important implication for dark energy. In this paper, we have calculated the power spectrum of the ISW effect in the time varying vacuum cosmological model, where the model parameter {beta}=4.407 is obtained by the observational constraint of the growth rate. It is found that the source of the ISW effect is not only affected by the different evolutions of the Hubble function H(a) and the dimensionless matter density {Omega}{sub m}(a), but also by the different growth function D{sub +}(a), all of which are changed due to the presence of a matter production term in the time varying vacuum model. However, the difference of the ISW effect in the {Lambda}(t)CDM model and the {Lambda}CDM model is lessened to a certain extent because of the integration from the time of last scattering to the present. It is implied that the observations of the galaxies with high redshift are required to distinguish the two models.
Reconstructing the integrated Sachs-Wolfe map with galaxy surveys
NASA Astrophysics Data System (ADS)
Muir, Jessica; Huterer, Dragan
2016-08-01
The integrated Sachs-Wolfe (ISW) effect is a large-angle modulation of the cosmic microwave background (CMB), generated when CMB photons traverse evolving potential wells associated with large scale structure (LSS). Recent efforts have been made to reconstruct maps of the ISW signal using information from surveys of galaxies and other LSS tracers, but investigation into how survey systematics affect their reliability has so far been limited. Using simulated ISW and LSS maps, we study the impact of galaxy survey properties and systematic errors on the accuracy of a reconstructed ISW signal. We find that systematics that affect the observed distribution of galaxies along the line of sight, such as photo-z and bias-evolution related errors, have a relatively minor impact on reconstruction quality. In contrast, however, we find that direction-dependent calibration errors can be very harmful. Specifically, we find that, in order to avoid significant degradation of our reconstruction quality statistics, direction-dependent number density fluctuations due to systematics must be controlled so that their variance is smaller than 10-6 (which corresponds to a 0.1% calibration). Additionally, we explore the implications of our results for attempts to use reconstructed ISW maps to shed light on the origin of large-angle CMB alignments. We find that there is only a weak correlation between the true and reconstructed angular momentum dispersion, which quantifies alignment, even for reconstructed ISW maps which are fairly accurate overall.
The integrated Sachs-Wolfe signal from BOSS superstructures
NASA Astrophysics Data System (ADS)
Granett, B. R.; Kovács, A.; Hawken, A. J.
2015-12-01
Cosmic structures leave an imprint on the microwave background radiation through the integrated Sachs-Wolfe (ISW) effect. We construct a template map of the linear signal using the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey at redshift 0.43 < z < 0.65. We verify the imprint of this map on the Planck cosmic microwave background (CMB) temperature map at the 97 per cent confidence level and show consistency with the density-temperature cross-correlation measurement. Using this ISW reconstruction as a template, we investigate the presence of ISW sources and further examine the properties of the Granett-Neyrinck-Szapudi supervoid and supercluster catalogue. We characterize the three-dimensional density profiles of these structures for the first time and demonstrate that they are significant structures. Model fits demonstrate that the supervoids are elongated along the line of sight and we suggest that this special orientation may be picked out by the void-finding algorithm in photometric redshift space. We measure the mean temperature profiles in Planck maps from public void and cluster catalogues. In an attempt to maximize the stacked ISW signal, we construct a new catalogue of superstructures based upon local peaks and troughs of the gravitational potential. However, we do not find a significant correlation between these structures and the CMB temperature.
Tay-Sachs disease and HEXA mutations among Moroccan Jews.
Kaufman, M; Grinshpun-Cohen, J; Karpati, M; Peleg, L; Goldman, B; Akstein, E; Adam, A; Navon, R
1997-01-01
Moroccan Jewry (N>750,000) is the only non-Ashkenazi Jewish community in which Tay-Sachs disease (TSD) is not extremely rare. Previous studies among Moroccan Jewish TSD families identified three HEXA mutations. In this study, extended to enzyme-defined and new obilgate TSD carriers, we found four additional mutations. One of them is a novel, IVS5-2(A-->G) substitution, resulting in exon skipping, and it was found only among enzyme-defined carriers. The seven HEXA identified mutations among Moroccan Jews are: deltaF(304/305), R170Q, IVS-2(A-->G), Y180X, E482K, 1278+TATC, and IVS12+1(G-->C). Their respective distribution among 51 unrelated enzyme-defined and obligate carriers is 22:19:6:1:1:1:1. The mutation(s) remain unknown in only three enzyme-defined carriers. Five of the seven Moroccan mutations, including the three most common ones, were not found among Ashkenazi Jews. Compared with the much larger and relatively homogeneous Ashkenazi population, the finding among Moroccan Jews probably reflects their much longer history. PMID:9338583
Lyddane-Sachs-Teller Analysis of Electronic Transitions
NASA Astrophysics Data System (ADS)
Karstens, William; Smith, David Y.
2015-03-01
We have explored the use of the Lyddane-Sachs-Teller (LST) relation for analysis of electronic optical spectra. This relation originated in the theory of IR lattice absorption and, in analogy with the high IR reflectivity of polar crystals, we demonstrate a substantial region of almost-metallic UV reflectivity above the fundamental electronic absorption in selected solids; it is especially pronounced in group IV elements. This electronic Reststrahlen is terminated by a well-defined longitudinal plasmon and may be understood within LST theory. The original LST formulation neglects dissipation; we show it reflects the geometric symmetry of a normalized dispersion curve based on relative frequencies and polarizabilities. If dissipation is included, absorption widths enter only in second order, so the original LST relation applies to optical spectra that can be approximated by the Lorentz model. The Kramers-Kronig based moments formulation of Noh and Sievers holds generally. The normalized curve is specified by a single strength parameter that may be used as an approximate index to characterize optical response. The dielectric response of covalent semiconductors will be discussed as examples of the LST relation and the dependence of energy-loss spectra on electronic properties. Supported in part by the US Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC02-06CH11357.
Nucleon form factors from high statistics mixed-action calculations with 2+1 flavors
Schroers, Wolfram; Edwards, Robert G; Engelhardt, Michael; Fleming, George Taminga; Hagler, Philipp; Lin, Huey-Wen; Lin, Mei-Feng; Meyer, Harvey B; Musch, Bernhard; Negele, John W; Orginos, Kostas; Pochinsky, Andrew V; Procura, Massimiliano; Renner, Dru B; Richards, David G; Syritsyn, Sergey N; Walker-Loud, Andre P
2009-12-01
We present new high-statistics results for nucleon form factors at pion masses of approximately 290, 350, 500, and 600 MeV using a mixed action of domain wall valence quarks on an improved staggered sea. We perform chiral fits to both vector and axial form factors and compare our results to experiment.
Skyrme model πNN form factor and the sea quark distribution of the nucleon
NASA Astrophysics Data System (ADS)
Fries, R. J.; Schäfer, A.
1998-06-01
We calculate the sea quark distribution of the nucleon in a meson cloud model. The novel feature of our calculation is the implementation of a special πNN form factor recently obtained by Holzwarth and Machleidt. This form factor is hard for small and soft for large momentum transfers. We show that this feature leads to a substantial improvement.
Form factors in quantum integrable models with GL(3)-invariant R-matrix
NASA Astrophysics Data System (ADS)
Pakuliak, S.; Ragoucy, E.; Slavnov, N. A.
2014-04-01
We study integrable models solvable by the nested algebraic Bethe ansatz and possessing GL(3)-invariant R-matrix. We obtain determinant representations for form factors of off-diagonal entries of the monodromy matrix. These representations can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.
Basic versus applied research: Julius Sachs (1832–1897) and the experimental physiology of plants
Kutschera, Ulrich
2015-01-01
The German biologist Julius Sachs was the first to introduce controlled, accurate, quantitative experimentation into the botanical sciences, and is regarded as the founder of modern plant physiology. His seminal monograph Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) was published 150 y ago (1865), when Sachs was employed as a lecturer at the Agricultural Academy in Poppelsdorf/Bonn (now part of the University). This book marks the beginning of a new era of basic and applied plant science. In this contribution, I summarize the achievements of Sachs and outline his lasting legacy. In addition, I show that Sachs was one of the first biologists who integrated bacteria, which he considered to be descendants of fungi, into the botanical sciences and discussed their interaction with land plants (degradation of wood etc.). This “plant-microbe-view” of green organisms was extended and elaborated by the laboratory botanist Wilhelm Pfeffer (1845–1920), so that the term “Sachs-Pfeffer-Principle of Experimental Plant Research” appears to be appropriate to characterize this novel way of performing scientific studies on green, photoautotrophic organisms (embryophytes, algae, cyanobacteria). PMID:26146794
Effective gene therapy in an authentic model of Tay-Sachs-related diseases.
Cachón-González, M Begoña; Wang, Susan Z; Lynch, Andrew; Ziegler, Robin; Cheng, Seng H; Cox, Timothy M
2006-07-01
Tay-Sachs disease is a prototypic neurodegenerative disease. Lysosomal storage of GM2 ganglioside in Tay-Sachs and the related disorder, Sandhoff disease, is caused by deficiency of beta-hexosaminidase A, a heterodimeric protein. Tay-Sachs-related diseases (GM2 gangliosidoses) are incurable, but gene therapy has the potential for widespread correction of the underlying lysosomal defect by means of the secretion-recapture cellular pathway for enzymatic complementation. Sandhoff mice, lacking the beta-subunit of hexosaminidase, manifest many signs of classical human Tay-Sachs disease and, with an acute course, die before 20 weeks of age. We treated Sandhoff mice by stereotaxic intracranial inoculation of recombinant adeno-associated viral vectors encoding the complementing human beta-hexosaminidase alpha and beta subunit genes and elements, including an HIV tat sequence, to enhance protein expression and distribution. Animals survived for >1 year with sustained, widespread, and abundant enzyme delivery in the nervous system. Onset of the disease was delayed with preservation of motor function; inflammation and GM2 ganglioside storage in the brain and spinal cord was reduced. Gene delivery of beta-hexosaminidase A by using adeno-associated viral vectors has realistic potential for treating the human Tay-Sachs-related diseases. PMID:16801539
Basic versus applied research: Julius Sachs (1832-1897) and the experimental physiology of plants.
Kutschera, Ulrich
2015-01-01
The German biologist Julius Sachs was the first to introduce controlled, accurate, quantitative experimentation into the botanical sciences, and is regarded as the founder of modern plant physiology. His seminal monograph Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) was published 150 y ago (1865), when Sachs was employed as a lecturer at the Agricultural Academy in Poppelsdorf/Bonn (now part of the University). This book marks the beginning of a new era of basic and applied plant science. In this contribution, I summarize the achievements of Sachs and outline his lasting legacy. In addition, I show that Sachs was one of the first biologists who integrated bacteria, which he considered to be descendants of fungi, into the botanical sciences and discussed their interaction with land plants (degradation of wood etc.). This "plant-microbe-view" of green organisms was extended and elaborated by the laboratory botanist Wilhelm Pfeffer (1845-1920), so that the term "Sachs-Pfeffer-Principle of Experimental Plant Research" appears to be appropriate to characterize this novel way of performing scientific studies on green, photoautotrophic organisms (embryophytes, algae, cyanobacteria). PMID:26146794
Axial form factors of the octet baryons in a covariant quark model
NASA Astrophysics Data System (ADS)
Ramalho, G.; Tsushima, K.
2016-07-01
We study the weak interaction axial form factors of the octet baryons, within the covariant spectator quark model, focusing on the dependence of four-momentum transfer squared, Q2. In our model the axial form factors GA(Q2) (axial-vector form factor) and GP(Q2) (induced pseudoscalar form factor) are calculated based on the constituent quark axial form factors and the octet baryon wave functions. The quark axial current is parametrized by the two constituent quark form factors, the axial-vector form factor gAq(Q2), and the induced pseudoscalar form factor gPq(Q2). The baryon wave functions are composed of a dominant S -state and a P -state mixture for the relative angular momentum of the quarks. First, we study in detail the nucleon case. We assume that the quark axial-vector form factor gAq(Q2) has the same function form as that of the quark electromagnetic isovector form factor. The remaining parameters of the model, the P -state mixture and the Q2 dependence of gPq(Q2), are determined by a fit to the nucleon axial form factor data obtained by lattice QCD simulations with large pion masses. In this lattice QCD regime the meson cloud effects are small, and the physics associated with the valence quarks can be better calibrated. Once the valence quark model is calibrated, we extend the model to the physical regime and use the low Q2 experimental data to estimate the meson cloud contributions for GA(Q2) and GP(Q2). Using the calibrated quark axial form factors and the generalization of the nucleon wave function for the other octet baryon members, we make predictions for all the possible weak interaction axial form factors GA(Q2) and GP(Q2) of the octet baryons. The results are compared with the corresponding experimental data for GA(0 ) and with the estimates of baryon-meson models based on S U (6 ) symmetry.
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false DD Form 1654, Evaluation... Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors. Contracting personnel may use the DD Form 1654 to furnish information to the transportation office for development...
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false DD Form 1654, Evaluation... Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors. Contracting personnel may use the DD Form 1654 to furnish information to the transportation office for development...
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false DD Form 1654, Evaluation... Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors. Contracting personnel may use the DD Form 1654 to furnish information to the transportation office for development...
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false DD Form 1654, Evaluation... Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors. Contracting personnel may use the DD Form 1654 to furnish information to the transportation office for development...
Off-shell electromagnetic form factors of pions and kaons in chiral perturbation theory
Rudy, T.E.; Fearing, H.W.; Scherer, S. )
1994-07-01
The off-shell electromagnetic vertex of a (pseudo)scalar particle contains, in general, two form factors [ital F] and [ital G] which depend, in addition to the squared momentum transfer, on the invariant masses associated with the initial and final legs of the vertex. Chiral perturbation theory to one loop is used to calculate the off-shell form factors of pions and kaons. The formalism of Gasser and Leutwyler, which was previously used to calculate the on-shell limit of the form factor [ital F], is extended to accommodate the most general form for off-shell Green's functions in the pseudoscalar meson sector. We find that chiral symmetry predicts that the form factors [ital F] of the charged pions and kaons go off-shell in the same way, i.e., the off-shell slope at the real photon point is given by the same new phenomenological constant [beta][sub 1]. Furthermore, it is shown that at order [ital p][sup 4] the form factor [ital F] of the [ital K][sup 0] does not show any off-shell dependence. The form factors [ital G] are all related to the form factors [ital F] in the correct fashion as required by the Ward-Takahashi identity. Numerical results for different off-shell kinematics are presented.
A Factor Analytic Study of the Coopersmith Self-Esteem Inventory Adult Short Form.
ERIC Educational Resources Information Center
Haines, Janet; Wilson, George V.
1988-01-01
A factor analysis was conducted on the Coopersmith Self-Esteem Inventory-Adult Short Form using 237 college students and 43 female office workers in Australia. Factors were found corresponding with three of the four subscales: general self, social self-peers, and home-parents (family). No factor related to the school-academic (work) subscale. (SLD)
ERIC Educational Resources Information Center
Samuel, Douglas B.; Mullins-Sweatt, Stephanie N.; Widiger, Thomas A.
2013-01-01
The Five-Factor Model Rating Form (FFMRF) is a one-page measure designed to provide an efficient assessment of the higher order domains of the Five Factor Model (FFM) as well as the more specific, lower order facets proposed by McCrae and Costa. Although previous research has suggested that the FFMRF's assessment of the lower order facets converge…
On-shell diagrams, Graßmannians and integrability for form factors
NASA Astrophysics Data System (ADS)
Frassek, Rouven; Meidinger, David; Nandan, Dhritiman; Wilhelm, Matthias
2016-01-01
We apply on-shell and integrability methods that have been developed in the context of scattering amplitudes in {N}=4 SYM theory to tree-level form factors of this theory. Focussing on the colour-ordered super form factors of the chiral part of the stress-tensor multiplet as an example, we show how to systematically construct on-shell diagrams for these form factors with the minimal form factor as further building block in addition to the three-point amplitudes. Moreover, we obtain analytic representations in terms of Graßmannian integrals in spinor helicity, twistor and momentum twistor variables. While Yangian invariance is broken by the operator insertion, we find that the form factors are eigenstates of the integrable spin-chain transfer matrix built from the monodromy matrix that yields the Yangian generators. Constructing them via the method of R operators allows to introduce deformations that preserve the integrable structure. We finally show that the integrable properties extend to minimal tree-level form factors of generic composite operators as well as certain leading singularities of their n-point loop-level form factors.
An experimental survey of the factors that affect leaching from low-level radioactive waste forms
Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.
1988-09-01
This report represents the results of an experimental survey of the factors that affect leaching from several types of solidified low-level radioactive waste forms. The goal of these investigations was to determine those factors that accelerate leaching without changing its mechanism(s). Typically, although not in every case,the accelerating factors include: increased temperature, increased waste loading (i.e., increased waste to binder ratio), and decreased size (i.e., decreased waste form volume to surface area ratio). Additional factors that were studied were: increased leachant volume to waste form surface area ratio, pH, leachant composition (groundwaters, natural and synthetic chelating agents), leachant flow rate or replacement frequency and waste form porosity and surface condition. Other potential factors, including the radiation environment and pressure, were omitted based on a survey of the literature. 82 refs., 236 figs., 13 tabs.
Can Nonrelativistic QCD Explain the γ γ*→ηc Transition Form Factor Data?
NASA Astrophysics Data System (ADS)
Feng, Feng; Jia, Yu; Sang, Wen-Long
2015-11-01
Unlike the bewildering situation in the γ γ*→π form factor, a widespread view is that perturbative QCD can decently account for the recent BABAR measurement of the γ γ*→ηc transition form factor. The next-to-next-to-leading-order perturbative correction to the γ γ*→ηc ,b form factor, is investigated in the nonrelativistic QCD (NRQCD) factorization framework for the first time. As a byproduct, we obtain, by far, the most precise order-αs2 NRQCD matching coefficient for the ηc ,b→γ γ process. After including the substantial negative order-αs2 correction, the good agreement between NRQCD prediction and the measured γ γ*→ηc form factor is completely ruined over a wide range of momentum transfer squared. This eminent discrepancy casts some doubts on the applicability of the NRQCD approach to hard exclusive reactions involving charmonium.
Interaction between droplets in a ternary microemulsion evaluated by the relative form factor method
Nagao, Michihiro; Seto, Hideki; Yamada, Norifumi L.
2007-06-15
This paper describes the concentration dependence of the interaction between water droplets coated by a surfactant monolayer using the contrast variation small-angle neutron scattering technique. In the first part, we explain the idea of how to extract a relatively model free structure factor from the scattering data, which is called the relative form factor method. In the second part, the experimental results for the shape of the droplets (form factor) are described. In the third part the relatively model free structure factor is shown, and finally the concentration dependence of the interaction potential between droplets is discussed. The result indicates the validity of the relative form factor method, and the importance of the estimation of the model free structure factor to discuss the nature of structure formation in microemulsion systems.
Measurements of the elastic electromagnetic form factor ratio {mu}pGEp/GMp via polarization transfer
Olivier Gayou; Oleksandr Glamazdin; Andrei Afanasev; Arunava Saha; Brendan Fox; Bogdan Wojtsekhowski; C. Chang; Cathleen Jones; Charles Glashausser; Charles Perdrisat; D. Crovelli; Daniel Simon; David Meekins; Demetrius Margaziotis; Dipangkar Dutta; Edgar Kooijman; Elaine Schulte; Edward Brash; Edward Kinney; Eugene Chudakov; Feng Xiong; Franco Garibaldi; Garth Huber; Gerfried Kumbartzki; Guido Urciuoli; Haiyan Gao; Jordan Hovdebo; James Kelly; Javier Gomez; Jens-Ole Hansen; Jian-Ping Chen; John Calarco; John LeRose; Joseph Mitchell; Juncai Gao; Konrad Aniol; Kamal Benslama; Kathy McCormick; Cornelis De Jager; Cornelis de Jager; Kevin Fissum; Krishni Wijesooriya; Louis Bimbot; Ludyvine Morand; Luminita Todor; Moskov Amarian; Marat Rvachev; Mark Jones; Martin Epstein; Meihua Liang; Michael Kuss; Nilanga Liyanage; Adam Sarty; Paul Ulmer; Pete Markowitz; Peter Bosted; R. Holt; Riad Suleiman; Richard Lindgren; Rikki Roche; Robert Michaels; Roman Pomatsalyuk; Ronald Gilman; Ronald Ransome; Stephen Becher; Scott Dumalski; Salvatore Frullani; Seonho Choi; Sergey Malov; Sonja Dieterich; Steffen Strauch; Steve Churchwell; Ting Chang; Viktor Gorbenko; Vina Punjabi; Wang Xu; Xiangdong Ji; Zein-Eddine Meziani; Zhengwei Chai
2001-09-01
We present measurements of the ratio of the proton elastic electromagnetic form factors, {mu}pGEp/GMp. The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine the longitudinal and transverse components of the recoil proton polarization in ep elastic scattering; the ratio of these polarization components is proportional to the ratio of the two form factors. These data reproduce the observation of Jones et al. [Phys. Rev. Lett. 84, 1398 (2000)], that the form factor ratio decreases significantly from unity above Q2 = 1 GeV2.
NASA Astrophysics Data System (ADS)
Jung, Ju-Hyun; Yakhshiev, Ulugbek; Kim, Hyun-Chul
2016-03-01
We investigate the medium modification of the generalized vector form factors of the nucleon, which include the electromagnetic and energy-momentum tensor form factors, based on an in-medium modified π -ρ -ω soliton model. We find that the vector form factors of the nucleon in nuclear matter fall off faster than those in free space, which implies that the charge radii of the nucleon become larger in nuclear medium than in free space. We also compute the corresponding transverse charge densities of the nucleon in nuclear matter, which clearly reveal the increasing of the nucleon size in nuclear medium.
Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach
Diana Nicmorus, Gernot Eichmann, Reinhard Alkofer
2010-12-01
We investigate the electromagnetic form factors of the Delta and the Omega baryons within the Poincare-covariant framework of Dyson-Schwinger and Bethe-Salpeter equations. The three-quark core contributions of the form factors are evaluated by employing a quark-diquark approximation. We use a consistent setup for the quark-gluon dressing, the quark-quark bound-state kernel and the quark-photon interaction. Our predictions for the multipole form factors are compatible with available experimental data and quark-model estimates. The current-quark mass evolution of the static electromagnetic properties agrees with results provided by lattice calculations.
Armstrong, David S.; McKeown, Robert
2012-11-01
Measurement of the neutral weak vector form factors of the nucleon provides unique access to the strange quark content of the nucleon. These form factors can be studied using parity-violating electron scattering. A comprehensive program of experiments has been performed at three accelerator laboratories to determine the role of strange quarks in the electromagnetic form factors of the nucleon. This article reviews the remarkable technical progress associated with this program, describes the various methods used in the different experiments, and summarizes the physics results along with recent theoretical calculations.