604 research outputs found
Open Semiclassical Strings and Long Defect Operators in AdS/dCFT Correspondence
We consider defect composite operators in a defect superconformal field
theory obtained by inserting an AdS_4 x S^2-brane in the AdS_5 x S^5
background. The one-loop dilatation operator for the scalar sector is
represented by an integrable open spin chain. We give a description to
construct coherent states for the open spin chain. Then, by evaluating the
expectation value of the Hamiltonian with the coherent states in a long
operator limit, a Landau-Lifshitz type of sigma model action is obtained. This
action is also derived from the string action and hence we find a complete
agreement in both SYM and string sides. We see that an SO(3)_H pulsating string
solution is included in the action and its energy completely agrees with the
result calculated in a different method. In addition, we argue that our
procedure would be applicable to other AdS-brane cases.Comment: 22 pages, 1 figure, LaTeX, minor corrections and references added.
v3) some new results added. shortened and accepted version in PR
Semiclassical Strings in Electric and Magnetic Fields Deformed Spacetimes
We first apply the transformation of mixing azimuthal and internal coordinate
or mixing time and internal coordinate to the 11D M-theory with a stack N
M2-branes to find the spacetime of a stack of N D2-branes with magnetic or
electric flux in 10 D IIA string theory, after the Kaluza-Klein reduction. We
then perform the T duality to the spacetime to find the background of a stack
of N D3-branes with magnetic or electric flux. In the near-horizon limit the
background becomes the magnetic or electric field deformed .
We adopt an ansatz to find the classical string solution which is rotating in
the deformed with three angular momenta in the three rotation planes. The
relations between the classical string energy and its angular momenta are found
and results show that the external magnetic and electric fluxes will increase
the string energy. Therefore, from the AdS/CFT point of view, the corrections
of the anomalous dimensions of operators in the dual SYM theory will be
positive. We also investigate the small fluctuations in these solutions and
discuss the effects of magnetic and electric fields on the stability of these
classical rotating string solutions. Finally, we find the possible solutions of
string pulsating on the deformed spacetimes and show that the corrections to
the anomalous dimensions of operators in the dual SYM theory are non-negative.Comment: Latex 18 pages, correct sec. 3.
Inhibition of the activity of pro-inflammatory secretory phospholipase A2 by acute phase proteins
Pro-Inflammatory non-pancreatic phospholipase A2 (sPLA2) is markedly over-expressed in acute systemic and chronic local inflammatory processes. Since in acute phase reaction sPLA2 is often over-expressed simultaneously with acute phase proteins (APP), it is important to determine whether APP interacts with sPLA2. We tested ten APPs for interaction with sPLA2 using as a substrate multilamellar Hposomes composed either of PC:Lyso PC or PE:Lyso PE. Using PC:Lyso PC substrate, CRP, lactoferrin and SAP were found to inhibit sPLA2 activity with an IC50 of 25 μg/ml, 7.5 μg/ml and 50 μg/ml, respectively, corresponding to 0.21 μM, 0.1 μM and 0.21 μM respectively. Using PE:Lyso PE substrate only SAP was inhibitory, with an IC50 of 10 μg/ml (0.04 μM). Phosphorylcholine abolished the inhibitory activity of CRP but not of SAP or lactoferrin. Addition of phosphorylethanolamine or of excess calcium had no effect on the inhibitory activity of APP. Limulin, lysozyme, transferrin, β2-microglobulin, α2-macroglobulin, human and bovine albumins had no effect on sPLA2 activity. Therefore neither the structure of pentraxins, or ironbinding, bacteriostatic property or amyloidogenic property preclude whether APP modulates sPLA2 activity. Inhibition of pro-inflammatory sPLA2 by APP may be one of the protective mechanisms of the acute phase reaction
Addressing Disciplinary Literacy: An Examination of Teachers’ Instruction in First Grade
Disciplinary literacy instruction during kindergarten through second grade enables students to begin developing facility with consuming, producing, and learning from texts in academic disciplines across their school careers and for full civic participation. Extant intervention studies and descriptions of practice in the primary grades offer understanding of disciplinary literacy instruction when it is enacted with researchers’ help and/or by teachers with expertise in disciplinary literacy. To address disciplinary literacy in the primary grades, insight into what primary teachers focus on and how they support students’ disciplinary literacy learning during their naturally-occurring instruction is needed. This exploratory collective case study examined the disciplinary literacy learning opportunities available in first-grade teachers’ instruction. Participants included four teachers in four elementary schools situated in a large city in the Midwest. Audio records and field notes were collected over a period of five months during teachers’ literacy instruction. Open coding, progressive refinement of codes, and categorical analyses revealed limited instructional emphasis on disciplinary literacy. When learning opportunities were observed, teachers’ foci and support centered on the social foundations of disciplinary literacy and included sharing of information and student practice. Also, problematic disciplinary literacy learning opportunities were noted. This study underscores the urgent need for additional attention to disciplinary literacy as it is situated within the primary grades, with particular import for how first-grade teachers enact disciplinary literacy instruction
Temperature and leaf nitrogen affect performance of plant species at range overlap
Plant growth and survival near range limits are likely sensitive to small changes in environmental conditions. Warming temperatures are causing range shifts and thus changes in species composition within range-edge ecotones; however, it is often not clear how temperature alters performance. Through an observational field study, we assessed temperature and nitrogen effects on survival and growth of co-occurring temperate (Acer saccharum) and boreal (Abies balsamea) saplings across their overlapping range limits in the Great Lakes region, USA. Across sampled ranges of soil texture, soil pH, and precipitation, it appears that temperature affects leaf nitrogen for A. saccharum near its northern range limit (R2=0.64), whereas there was no significant leaf N ~ temperature relationship for A. balsamea. Higher A. saccharum leaf N at warm sites was associated with increased survival and growth. Abies balsamea survival and growth were best modeled with summer temperature (negative relationship); performance at warm sites depended upon light availability, suggesting the shade-tolerance of this species near its southern range limits may be mediated by temperature. The ranges of these two tree species overlap across millions of hectares, and temperature and temperature-mediated nitrogen likely play important roles in their relative performance
Tenidap sodium inhibits secretory non-pancreatic phospholipase A2 synthesis by foetal rat calvarial osteoblasts
Tenidap (TD) was initially defined as a dual inhibitor of cyclooxygenase and lipoxygenase. This study was designed to assess its inhibitory activity against proinflammatory phospholipase A2. This study shows that TD inhibits the synthesis of pro-inflammatory secretory non-pancreatic phospholipase A2 (sPLA2). Concentrations as low as 0.25 μg/ml (0.725 μM) reduced the release of sPLA2 by 40% from foetal rat calvarial osteoblasts stimulated with IL-1β and TNFα, whereas a concentration of 2.5 μg/ml (7.25 μM) reduced the release by over 80%. TD also markedly reduced the release of sPLA2 from unstimulated cells. There was no direct inhibition of sPLA2 enzymatic activity by TD in vitro. Northern blot analysis showed that TD did not affect the sPLA2 mRNA levels; however, immunoblotting showed a dose-dependent reduction in sPLA2 enzyme. These results, together with a marked reduction in sPLA2 enzymatic activity, suggest that TD inhibits sPLA2 synthesis at the post-transcriptional level. Therefore TD seems to inhibit the arachidonic acid cascade proximally to cyclooxygenase and lipoxygenase and its anti-inflammatory activity may be related at least in part to the inhibition of sPLA2 synthesis
Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment
We present a phenomenological model which describes the formation of a
Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and
at the LHC, and its decay to non-strange baryons and Strangelets. We describe
the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in
an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta <
7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations
for the response of the CASTOR calorimeter, and in particular to the traversal
of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR
Three-Point Functions in N=4 SYM Theory at One-Loop
We analyze the one-loop correction to the three-point function coefficient of
scalar primary operators in N=4 SYM theory. By applying constraints from the
superconformal symmetry, we demonstrate that the type of Feynman diagrams that
contribute depends on the choice of renormalization scheme. In the planar
limit, explicit expressions for the correction are interpreted in terms of the
hamiltonians of the associated integrable closed and open spin chains. This
suggests that at least at one-loop, the planar conformal field theory is
integrable with the anomalous dimensions and OPE coefficients both obtainable
from integrable spin chain calculations. We also connect the planar results
with similar structures found in closed string field theory.Comment: 34 pages, 9 figures, harvmac; references adde
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