654 research outputs found
Vacuum quark condensate, chiral Lagrangian, and Bose-Einstein statistics
In a series of articles it was recently claimed that the quantum
chromodynamic (QCD) condensates are not the properties of the vacuum but of the
hadrons and are confined inside them. We point out that this claim is
incompatible with the chiral Lagrangian and Bose-Einstein statistics of the
Goldstone bosons (pions) in chiral limit and conclude that the quark condensate
must be the property of the QCD vacuum.Comment: 4 Pages, To appear in Phys. Lett.
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Diffusion of Botulinum Toxins
Background: It is generally agreed that diffusion of botulinum toxin occurs, but the extent of the spread and its clinical importance are disputed. Many factors have been suggested to play a role but which have the most clinical relevance is a subject of much discussion. Methods: This review discusses the variables affecting diffusion, including protein composition and molecular size as well as injection factors (e.g., volume, dose, injection method). It also discusses data on diffusion from comparative studies in animal models and human clinical trials that illustrate differences between the available botulinum toxin products (onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and rimabotulinumtoxinB). Results: Neither molecular weight nor the presence of complexing proteins appears to affect diffusion; however, injection volume, concentration, and dose all play roles and are modifiable. Both animal and human studies show that botulinum toxin products are not interchangeable, and that some products are associated with greater diffusion and higher rates of diffusion-related adverse events than others. Discussion: Each of the botulinum toxins is a unique pharmacologic entity. A working knowledge of the different serotypes is essential to avoid unwanted diffusion-related adverse events. In addition, clinicians should be aware that the factors influencing diffusion may range from properties intrinsic to the drug to accurate muscle selection as well as dilution, volume, and dose injected
What Kallah Rabbati Teaches Us about the Redaction of the Talmud
Kalá Rabati es un texto rabínico amoraíta (c.
350–400 de nuestra era) poco conocido con
una estrecha relación con el Talmud de Babilonia. Hay pasajes en Kalá Rabati que tienen
paralelos en el Talmud con ciertas variantes
que exponen el proceso editorial de ambos
textos. Además, la manera en que el Talmud
se redactó es un enigma para los estudios talmúdicos. Hasta ahora, este análisis ha sido
tautológico: se descifra cómo se redactó el
Talmud por medio de datos que provienen
exclusivamente del Talmud mismo. Este estudio demuestra que Kalá Rabati nos ayuda a
descubrir el proceso de edición del Talmud,
señalando el importante papel que los transmisores desempeñaron en la redacción de algunos pasajes, constituyendo a veces la voz
anónima del mismo.Kallah Rabbati is a little-known late amoraic
(c. 350–400 CE) rabbinic text with a close relationship to the Babylonian Talmud. Passages in Kallah Rabbati parallel passages in the
Talmud with variations that expose the redactional process of both texts. How the Talmud
was redacted is one of the enigmas of Talmudic studies. To date, that analysis has been
tautological: deciphering how the Talmud was
edited from data gathered exclusively from the
Talmud itself. This study shows that Kallah
Rabbati can be an invaluable aid in uncovering that process, pointing to the transmitters
as having played a crucial role in the editing
of some Talmudic passages and even at times
comprising its anonymous voice
Lo que nos enseña Kalá Rabati sobre la redacción del Talmud
Kallah Rabbati is a little-known late amoraic (c. 350–400 CE) rabbinic text with a close relationship to the Babylonian Talmud. Passages in Kallah Rabbati parallel passages in the Talmud with variations that expose the redactional process of both texts. How the Talmud was redacted is one of the enigmas of Talmudic studies. To date, that analysis has been tautological: deciphering how the Talmud was edited from data gathered exclusively from the Talmud itself. This study shows that Kallah Rabbati can be an invaluable aid in uncovering that process, pointing to the transmitters as having played a crucial role in the editing of some Talmudic passages and even at times comprising its anonymous voice.Kalá Rabati es un texto rabínico amoraíta (c. 350–400 de nuestra era) poco conocido con una estrecha relación con el Talmud de Babilonia. Hay pasajes en Kalá Rabati que tienen paralelos en el Talmud con ciertas variantes que exponen el proceso editorial de ambos textos. Además, la manera en que el Talmud se redactó es un enigma para los estudios talmúdicos. Hasta ahora, este análisis ha sido tautológico: se descifra cómo se redactó el Talmud por medio de datos que provienen exclusivamente del Talmud mismo. Este estudio demuestra que Kalá Rabati nos ayuda a descubrir el proceso de edición del Talmud, señalando el importante papel que los transmisores desempeñaron en la redacción de algunos pasajes, constituyendo a veces la voz anónima del mismo
Nickel and chromium release in vitro from newly engineered brackets
Thesis (MSD)--Boston University, Goldman School of Dental Medicine, 2005 (Orthodontics).Includes bibliographical references: leaves 88-91.Orthodontic brackets are susceptible to corrosion in the oral environment. This corrosion manifests itself by releasing ions from its alloy into solution. If these ions are released at sufficient quantities, they have the potential to cause allergic reactions in sensitive patients. The first purpose of this study was to compare the release of chromium and nickel ions into artificial saliva between brackets marketed as highly biocompatible and older brackets which did not attempt to limit corrosion. The second purpose of this study was to determine if electrogalvanic corrosion takes place between a bracket and a wire while ligated. Prior to experimentation, all brackets were examined under SEM with an energy dispersive x-ray microanalyzer to determine composition. Twelve brackets from each brand were immersed in artificial saliva for 24 hours, 7 (1+6) days, and 28 (1+6+21) days at which times they were analyzed by ICP MS for chromium and nickel ions. In addition, Ni-Ti wire, Ni-Ti wire ligated to a Cr- Co bracket, and Cr-Co brackets alone were immersed in artificial saliva for one week and then analyzed by ICP-MS. The results were as follows: (1) The newly engineered brackets tested (with the exception of GAC's Platina bracket) release fewer Cr & Ni ions than the original AISI 303 Diamond bracket by Ormco. (2) GAC's Platina palladium covered brackets exhibit a significant surge of Cr (P=0.01) & Ni (P=0.02) release in the first 24 hours after placement in artificial saliva due to voids discovered in the plating. (3) Maximum release of chromium and nickel ions occurred in the first 24 hours after placement in artificial saliva. (4) On average, the one-piece brackets used in this study, released less nickel ions over time than did two-piece brackets. (5) The Ovation Platina and Diamond brackets released the largest amount of nickel ions over the course of the experiment, while the Sprint, Elite Opti-MIM, Elite Opti-MIM NL and Nu-Edge MBT brackets released less nickel ions. (6) The Ovation Platina released the largest amount of chromium ions over the course of the experiment, while the Diamond, Elite Opti-MIM NL and Nu-Edge MBT brackets released an intermediate amount of chromium ions, while the Sprint and Elite Opti-MIM brackets released the fewest amount of ions. (7) No evidence of galvanic corrosion has been shown between a Cr Co bracket and a Ni-Ti wire while ligated by a plastic ligature
Mesonic Form Factors
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.Comment: 7 pages, 6 figures, Workshop on Lattice Hadron Physics 2003 (LHP2003
An appreciation of the prescience of Don Gilbert (1930‐2011): master of the theory and experimental unraveling of biochemical and cellular oscillatory dynamics
We review Don Gilbert's pioneering seminal contributions that both detailed the mathematical principles and the experimental demonstration of several of the key dynamic characteristics of life. Long before it became evident to the wider biochemical community, Gilbert proposed that cellular growth and replication necessitate autodynamic occurrence of cycles of oscillations that initiate, coordinate, and terminate the processes of growth, during which all components are duplicated and become spatially re‐organized in the progeny. Initiation and suppression of replication exhibit switch‐like characteristics: i.e., bifurcations in the values of parameters that separate static and autodynamic behavior. His limit cycle solutions present models developed in a series of papers reported between 1974 and 1984, and these showed that most or even all of the major facets of the cell division cycle could be accommodated. That the cell division cycle may be timed by a multiple of shorter period (ultradian) rhythms, gave further credence to the central importance of oscillatory phenomena and homeodynamics as evident on multiple time scales (seconds to hours). Further application of the concepts inherent in limit cycle operation as hypothesized by Gilbert more than 50 years ago are now validated as being applicable to oscillatory transcript, metabolite and enzyme levels, cellular differentiation, senescence, cancerous states, and cell death. Now, we reiterate especially for students and young colleagues, that these early achievements were even more exceptional, as his own lifetime's work on modeling was continued with experimental work in parallel with his predictions of the major current enterprises of biological research
The Structure of the QCD Potential in 2+1 Dimensions
We calculate the screening and anti-screening contributions to the
inter-quark potential in 2+1 dimensions, which is relevant to the high
temperature limit of QCD. We demonstrate that the relative strength of
screening to anti-screening agrees with the 3+1 dimensional theory to better
than one percent accuracy.Comment: 9 pages, LaTeX, no figures, version to appear in Journa
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