bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle metabolism and acid-base status during exercise in forearm work-related myalgia measured with31P-MRS
Authors: Raymer Graydon H. , Green Howard J. , Ranney Don A. , Marsh Greg D. , Thompson R. Terry
Published: December 2008

In this study, we examined muscle metabolic and acid-base status during incremental wrist extension exercise in the forearm of individuals with work-related myalgia (WRM). Eighteen women employed in full-time occupations involving repetitive forearm labor were recruited in this cross-sectional study. Nine of these women were diagnosed with WRM, while the other nine had no previous WRM history and were used as age-matched controls (Con). Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) was used to noninvasively monitor the intracellular concentrations of phosphocreatine ([PCr]) and inorganic phosphate ([Pi]) as well as intracellular pH (pHi) status during exercise in WRM and Con. We observed a 38% decreased work capacity in WRM compared with Con [0.18 W (SD 0.03) vs. 0.28 W (SD 0.10); P = 0.007]. Piecewise linear regression of the incremental exercise data revealed that the onset of a faster decrease in pHi(i.e., the pH threshold, pHT) and the onset of a faster increase in log([Pi]/[PCr]) (i.e., the phosphorylation threshold, PT) occurred at a 14% relatively lower power output in WRM [pHT: 45.2% (SD 5.3) vs. 59.0% (SD 4.6), P < 0.001; PT: 44.8% (SD 4.3) vs. 57.8% (SD 3.1), P < 0.001; % of peak power output, Con vs. WRM, respectively]. Monoexponential modeling of the kinetics of [PCr] and pHirecovery following exercise demonstrated a slower ( P = 0.005) time constant (τ) for [PCr] in WRM [113 s (SD 25)] vs. Con [77 s (SD 23)] and a slower ( P = 0.007) τ for pHiin WRM [370 s (SD 178)] vs. Con [179 s (SD 52)]. In conclusion, our results suggest that WRM is associated with an increased reliance on nonoxidative metabolism. Possible mechanisms include a reduction in local muscle blood flow and perfusion, an increased ATP cost of force production, or both.
Maximal lengthening contractions induce different signaling responses in the type I and type II fibers of human skeletal muscle
Authors: Tannerstedt Jörgen , Apró William , Blomstrand Eva
Published: December 2008

The molecular mechanisms by which resistance exercise enlarges muscle mass, particularly the mass of fast-twitch type II fibers, are likely to involve enhanced phosphorylation/activation of key enzymes regulating protein synthesis. The hypothesis is that resistance exercise influences the phosphorylation of such key signaling proteins to a greater extent in type II than in type I fibers. Six recreationally active male subjects performed four sets of six maximal lengthening contractions with one leg. Muscle biopsies were taken from the vastus lateralis before and immediately after exercise and following 1 and 2 h of recovery. Samples were freeze-dried, and individual muscle fibers were dissected out and identified as type I or type II after staining for myosin ATPase. Phosphorylation of p70S6kon Thr389and S6 in type II fibers was increased three-to fourfold and six- to ninefold ( P < 0.05), respectively, 1 and 2 h after exercise, whereas phosphorylation in type I fibers remained unchanged. Phosphorylation of Akt, mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) was unaltered in both fiber types, whereas that of eukaryotic elongation factor 2 (eEF2) was attenuated 20–45% ( P < 0.05) in type II fibers during recovery. Phosphorylation of ERK1/2 was elevated six- to sevenfold ( P < 0.05) immediately after exercise, and p38 MAPK phosphorylation was increased three- to fourfold ( P < 0.05) for as long as 1 h after exercise in both types of fibers, although the level was markedly higher in type II fibers ( P < 0.05). In conclusion, the elevation of p70S6kand the reduction of eEF2 phosphorylation in the type II fibers following resistance exercise suggest stimulation of protein synthesis, which may contribute to a more pronounced enlargement of these fibers. Our findings also suggest that p70S6kis activated, at least in part, via pathways not involving Akt-mTOR and MAPK.
LBNP exercise protects aerobic capacity and sprint speed of female twins during 30 days of bed rest
Authors: Lee Stuart M. C. , Schneider Suzanne M. , Boda Wanda L. , Watenpaugh Donald E. , Macias Brandon R. , Meyer R. Scott , Hargens Alan R.
Published: December 2008

We have shown previously that treadmill exercise within lower body negative pressure (LBNPex) maintains upright exercise capacity (peak oxygen consumption, V̇o2peak) in men after 5, 15, and 30 days of bed rest (BR). We hypothesized that LBNPex protects treadmill V̇o2peak and sprint speed in women during a 30-day BR. Seven sets of female monozygous twins volunteered to participate. Within each twin set, one was randomly assigned to a control group (Con) and performed no countermeasures, and the other was assigned to an exercise group (Ex) and performed a 40-min interval (40–80% pre-BR V̇o2peak) LBNPex (51 ± 5 mmHg) protocol, plus 5 min of static LBNP, 6 days per week. Before and immediately after BR, subjects completed a 30.5-m sprint test and an upright graded treadmill test to volitional fatigue. These results in women were compared with previously reported reductions in V̇o2peak and sprint speed in male twins after BR. In women, sprint speed (−8 ± 2%) and V̇o2peak (−6 ± 2%) were not different after BR in the Ex group. In contrast, both sprint speed (−24 ± 5%) and V̇o2peak (−16 ± 3%) were significantly less after BR in the Con group. The effect of BR on sprint speed and V̇o2peak after BR was not different between women and men. We conclude that treadmill exercise within LBNP protects against BR-induced reductions in V̇o2peak and sprint speed in women and should prove effective during long-duration spaceflight.
Angiopoietin-2 Exocytosis Is Stimulated by Sphingosine-1-Phosphate in Human Blood and Lymphatic Endothelial Cells
Authors: Jang Cholsoon , Koh Young Jun , Lim Nam Kyu , Kang Hyun Jung , Kim Duk Hoon , Park Sung Kwang , Lee Gyun Min , Jeon Choon Ju , Koh Gou Young
Published: December 2008

Objective—

Although diverse functions of angiopoietin-2 (Ang2) have been revealed, little is known about upstream signaling molecules regulating Ang2 exocytosis. We therefore investigated the mechanism of Ang2 exocytosis in human blood and lymphatic endothelial cells (BECs and LECs) by stimulation with sphingosine-1-phosphate (S1P).

Methods and Results—

By immunostaining and ELISA analyses using our newly developed human Ang2-specific antibodies, Ang2 exocytosis from human endothelial cells was examined. Both exogenous and endogenous S1P trigger rapid Ang2 exocytosis in time- and dose-dependent manners. Intriguingly, S1P-induced Ang2 exocytosis is higher in LECs than BECs. These effects of S1P are mainly mediated by the endothelial differentiation gene receptor 1, which subsequently activates its downstream phospholipase C and intracellular calcium mobilization to trigger Ang2 exocytosis. Consistently, S1P also dramatically stimulates Ang2 exocytosis from the ECs of ex vivo–incubated blood vessels.

Conclusion—

These results imply that the rapid secretion of Ang2 by exocytosis from endothelial cells is another possible mechanism underlying S1P-induced angiogenesis and inflammation.
Multi-Hit Inhibition of Circulating and Cell-Associated Components of the Toll-Like Receptor 4 Pathway by Oxidized Phospholipids
Authors: von Schlieffen Elena , Oskolkova Olga V. , Schabbauer Gernot , Gruber Florian , Blüml Stephan , Genest Melinda , Kadl Alexandra , Marsik Claudia , Knapp Sylvia , Chow Jesse , Leitinger Norbert , Binder Bernd R. , Bochkov Valery N.
Published: December 2008

Objective—

Oxidized phospholipids (OxPLs) that are abundant in atherosclerotic lesions are increasingly recognized as context-dependent lipid mediators demonstrating both pro- and antiinflammatory activities. Molecular mechanisms of their effects are largely unknown. Here we present novel information on the mechanisms whereby OxPLs modulate activation of TLR4 by lipopolysaccharide (LPS).

Methods and Results—

We show, using several cell types and various inflammatory genes as readouts, that different classes and molecular species of OxPLs do not stimulate TLR4 but exert prominent inhibitory effects on LPS-induced reactions. Our data demonstrate that binding of OxPLs to the LPS-binding protein (LBP) and CD14 prevents recognition of LPS by these proteins, thus impairing activation of TLR4. In addition, OxPLs inhibited LBP- and CD14-independent activation of TLR4 by the synthetic TLR4 agonist E6020 indicating that in parallel with LBP and CD14, OxPLs target cell-associated steps in TLR4 cascade.

Conclusions—

Our data suggest that OxPLs inhibit action of LPS via a multi-hit mechanism. These results support the notion that OxPLs are endogenous inhibitors of TLR4 produced in response to oxidative stress.
Effect of Rimonabant on the High-Triglyceride/ Low–HDL-Cholesterol Dyslipidemia, Intraabdominal Adiposity, and Liver Fat
Authors: Després Jean-Pierre , Ross Robert , Boka Gabor , Alméras Natalie , Lemieux Isabelle
Published: December 2008

Background—

Rimonabant, the first selective cannabinoid type 1 (CB
1
) receptor antagonist, improves cardiometabolic risk factors in overweight/obese patients. ADAGIO-Lipids assessed the effect of rimonabant on cardiometabolic risk factors and intraabdominal and liver fat.

Methods and Results—

803 abdominally obese patients with atherogenic dyslipidemia (increased triglycerides [TG] or reduced high-density lipoprotein–cholesterol [HDL-C]) were randomized to placebo or rimonabant 20 mg/d for 1 year. HDL-C and TG were coprimary end points. Intraabdominal (visceral) and liver fat were measured by computed tomography in a subgroup of 231 patients. In total, 73% of rimonabant- and 70% of placebo-treated patients completed the study treatment. Rimonabant 20 mg produced significantly greater changes from baseline versus placebo in HDL-C (+7.4%) and TG levels (−18%;
P
<0.0001), as well as low-density lipoprotein (LDL) and HDL particle sizes, apolipoprotein A1 and B, HDL
2
, HDL
3
, C-reactive protein, and adiponectin levels (all
P
<0.05). Rimonabant decreased abdominal subcutaneous adipose tissue (AT) cross-sectional area by 5.1% compared to placebo (
P
<0.005), with a greater reduction in visceral AT (−10.1% compared to placebo;
P
<0.0005), thereby reducing the ratio of visceral/subcutaneous AT (
P
<0.05). Rimonabant significantly reduced liver fat content (liver/spleen attenuation ratio;
P
<0.005). Systolic (−3.3 mm Hg) and diastolic (−2.4 mm Hg) blood pressure were significantly reduced with rimonabant versus placebo (
P
<0.0001). The safety profile of rimonabant was consistent with previous studies; gastrointestinal, nervous system, psychiatric, and general adverse events were more common with rimonabant 20 mg.

Conclusions—

In abdominally obese patients with atherogenic dyslipidemia, rimonabant 20 mg significantly improved multiple cardiometabolic risk markers and induced significant reductions in both intraabdominal and liver fat.
Platelet Activation by Low Concentrations of Intact Oxidized LDL Particles Involves the PAF Receptor
Authors: Chen Rui , Chen Xi , Salomon Robert G. , McIntyre Thomas M.
Published: December 2008

Objective—Mitochondrial depolarization aids platelet activation. Oxidized LDL (oxLDL) contains the medium length oxidatively truncated phospholipid hexadecyl azelaoyl-lysoPAF (HAz-LPAF) that disrupts mitochondrial function in nucleated cells, so oxLDL may augment platelet activation.

Methods and Results—Flow cytometry showed intact oxLDL particles synergized with subthreshold amounts of soluble agonists to increase intracellular Ca2+, and initiate platelet aggregation and surface expression of activated gpIIb/IIIa and P-selectin. oxLDL also induced aggregation and increased intracellular Ca2+in FURA2-labeled cells by itself at low, although not higher, concentrations. HAz-LPAF, alone and in combination with substimulatory amounts of thrombin, rapidly increased cytoplasmic Ca2+and initiated aggregation. HAz-LPAF depolarized mitochondria in intact platelets, but this required concentrations beyond those that directly activated platelets. An unexpectedly large series of chemically pure truncated phospholipids generated by oxidative fragmentation of arachidonoyl-, docosahexaneoyl-, or linoleoyl alkyl phospholipids were platelet agonists. The PAF receptor, thought to effectively recognize only phospholipids with very shortsn-2 residues, was essential for platelet activation because PAF receptor agonists blocked signaling by all these medium length phospholipids and oxLDL.

Conclusions—Intact oxLDL particles activate platelets through the PAF receptor, and the PAF receptor responds to a far wider range of oxidized phospholipids in oxLDL than anticipated.
Early Growth Response-1 Regulates Angiopoietin-1-Induced Endothelial Cell Proliferation, Migration, and Differentiation
Authors: Abdel-Malak Nelly A. , Mofarrahi Mahroo , Mayaki Dominique , Khachigian Levon M. , Hussain Sabah N.A.
Published: December 2008

Objective—

Angiopoietin-1 (Ang-1) is an important regulator of angiogenesis in endothelial cells. It promotes migration, proliferation, and differentiation of cells, although the regulating factors involved in these processes remain unclear. In this study, we evaluated the contribution of the transcription factor early growth response-1 (Egr-1) to Ang-1-induced angiogenesis in human umbilical vein endothelial cells (HUVECs).

Methods and Results—

Expression of Egr-1 was evaluated with real-time PCR and immunoblotting, whereas Egr-1 DNA binding activity was monitored with electrophoretic mobility shift assays. Cell migration was measured with wound healing and Boyden chamber assays, whereas cell proliferation and differentiation of cells into capillary-like tube structures were monitored with cell counting, BrdU incorporation and Matrigels. To selectively inhibit Egr-1 expression, we used both siRNA oligonucleotides and specific DNAzymes. Egr-1 mRNA expression rose approximately 9-fold within 2 hours of Ang-1 exposure and declined thereafter. Upregulation of Egr-1 expression was accompanied by an increase in nuclear mobilization and augmented DNA binding. These processes were mediated through the Erk1/2, PI-3 kinase/AKT, and mTOR pathways. Knockdown of Egr-1 expression completely abrogated Ang-1-induced endothelial migration and significantly reduced proliferation and capillary-like tube formation of HUVECs that overexpress Ang-1.

Conclusion—

Ang-1 triggers significant and transient induction of Egr-1, and Egr-1 contributes to Ang-1-induced endothelial cell migration and proliferation.
Allo-restricted CTLs generated by coculturing of PBLs and autologous monocytes loaded with allogeneic peptide/HLA/IgG1-Fc fusion protein
Authors: Weng Xiufang , Lu Shengjun , Zhong Maohua , Liang Zhihui , Shen Guanxin , Chen Jianguo , Wu Xiongwen
Published: December 2008

The graft-versus-leukemia effect of allogeneic marrow transplantation suggests the dramatic effect of the allogeneic T cell to eradicate malignant disease. Preparation and adoptive transfusion of tumor-specific T cells from HLA-mismatched donors might be expected to circumvent CTL tolerance to the tumor. In this study, a soluble, divalent HLA-A2 molecule was constructed with the Fc part of human IgG1 and was pulsed with a peptide related to melanoma tyrosinase 368–376 [Tyr368–376 (Tyr)] to form the Tyr/HLA-A2 dimer, which allowed loading onto monocytes via interaction of the Fc and FcR. The HLA-A2-negative (HLA-A2-ve) monocytes loaded with the Tyr/HLA-A2 dimer acted as allo-APC with copies of a single allogeneic epitope. After coculture of the HLA-A2-ve PBLs and autologous monocytes loaded with the dimer, CD8+ cells in the coculture show an obvious proliferation and increased frequency of Tyr/HLA-A2 tetramer-stained cells. The sorted Tyr/HLA-A2 tetramer-positive CD8+ cells display an elevated cytotoxic activity against HLA-A2-positive melanoma cells expressing tyrosinase endogenously (i.e., SK-Mel-5) but little against tyrosinase-negative melanoma cells (i.e., A375). The coculture of PBLs and autologous monocytes loaded with allogeneic peptide/HLA complexes offers a novel approach to expand allo-restricted, peptide-specific CTLs, which might be a potential arsenal for treatment of patients with malignant disease, if the tumor-related epitope were defined.
Pivotal Advance: Toll-like receptor regulation of scavenger receptor-A-mediated phagocytosis
Authors: Amiel Eyal , Alonso Anselmo , Uematsu Satoshi , Akira Shizuo , Poynter Matthew E , Berwin Brent
Published: December 2008

Class-A scavenger receptors (SR-A) and TLR mediate early immune responses against pathogenic bacteria. SR-A and TLR molecules are expressed on phagocytes and interact with common ligands from Gram-negative and Gram-positive bacteria; however, the contribution of TLR activity to SR-A-mediated phagocytosis has not been assessed directly. Herein, we provide genetic and functional evidence that ligand- and TLR-specific stimuli synergize with SR-A to mediate bacterial phagocytosis. Although complete loss of SR-A (SR-A−/−) is known to impair bacterial clearance, here we identify the first deficiency attributable to SR-A heterozygosity: SR-A+/−TLR4+/− cells and mice are impaired significantly in the clearance of Gram-negative Escherichia coli. This phenotype is specific to the TLR signaling event, as SR-A+/−TLR4+/− cells are not deficient for the clearance of Gram-positive Staphylococcus aureus bacteria, which contain cell-surface TLR2 ligands but lack TLR4 ligands. We demonstrate that this is a global, phagocytic mechanism, regulated independently by multiple TLRs, as analogous to the SR-A+/−TLR4+/− deficit, SR-A+/−TLR2+/− cells are impaired for S. aureus uptake. In support of this, we show that SR-A+/−MyD88+/− cells recapitulate the phagocytosis defect observed in SR-A+/−TLR4+/− cells. These data identify for the first time that TLR-driven innate immune responses, via a MyD88 signaling mechanism, regulate SR-A-dependent phagocytosis of bacteria. These findings provide novel insights into how innate immune cells control SR-A-mediated trafficking and are the first demonstration that subtle changes in the expression of SR-A and TLRs can substantially affect host bacterial clearance.
Retinoic acid regulates Fas-induced apoptosis in Jurkat T cells: reversal of mitogen-mediated repression of Fas DISC assembly
Authors: Engedal Nikolai , Auberger Patrick , Blomhoff Heidi Kiil
Published: December 2008

The effect of the immune regulator vitamin A on T cell death has been poorly characterized. In the present study, we demonstrate that an active metabolite of vitamin A, retinoic acid (RA), promotes cell death in Jurkat leukemic T cells by counteracting mitogen-mediated repression of Fas-induced apoptosis. The effect of RA was dose-dependent, and at the optimal concentration of 1 μM, repression of Fas-induced cell death by the mitogens 12-O-tetradecanoylphorbol 13-acetate (TPA) or Con A was reversed by ∼50% and 30%, respectively. RA promoted apoptosis rather than necrosis, as judged by analysis of cell morphology, mitochondrial membrane depolarization, and DNA fragmentation. TPA-mediated protection from Fas-induced apoptosis is dependent on ERK and NF-κB. However, analyses of ERK and NF-κB activities and expression of target genes indicated that RA-mediated counteraction of the protective effect of TPA did not involve negative crosstalk with ERK or NF-κB survival pathways. RA-induced cell death was accompanied by enhanced cleavage of procaspase-3, -6, and -8, as well as enhanced cleavage of DNA fragmentation factor 45. Interestingly, RA-mediated cleavage of procaspase-8 occurred very early and before any effect of RA could be detected on procaspase-3 cleavage, suggesting that RA might act at the level of the Fas death-inducing signaling complex (DISC). Indeed, DISC immunoprecipitation studies revealed that RA treatment reversed the inhibitory effect of TPA on CH11-induced recruitment and processing of procaspase-8 at the DISC. In conclusion, we have identified a role of RA in abrogating mitogen-mediated repression of Fas DISC assembly, thus enhancing Fas-induced apoptosis in leukemic T cells.
Marketing Your Nurse-Managed Practice: Become a “Marketpreneur”
Authors: Mackey Thomas A. , Estala Stephanie
Published: January 2009

Nurse practitioners are finding that the business aspects of practice are difficult to master yet vital to its existence. Unless a practice is based on sound business principles, income suffers and the practice eventually fails. This article discusses one of the most important business aspects of your practice—marketing. It reviews how to develop a marketing plan and what to include in that plan, lists several marketing methods, and finally outlines how to develop an elevator pitch that you can deliver in 30 seconds or less.
A Systematic Review: Dexmedetomidine Versus Placebo to Decrease the Incidence of Emergence Delirium/Emergence Agitation (ED/EA) in Pediatric Patients
Authors: Enlow William M. , Ardizzone Laura L.
Published: January 2009

Background: Emergence delirium/emergence agitation (ED/EA) has a reported incidence of up to 73% after general anesthesia (GA) in children. The implications of ED/EA are broad and include patient complications, increased nursing care intensity, and increased hospital costs. Objective: The objective of this systematic review is to appraise available randomized control trials (RCTs) comparing intravenous dexmedetomidine to placebo in decreasing the incidence of ED/EA among children after GA. Method: We conducted a comprehensive search of the literature using Medline from 1950 through September 2007 and CINHAL from 1982 through September 2007, as well as PubMed and The Cochrane Library. Four RCTs were included in the review and were appraised for methodological quality by each author. Results: Evaluation of the primary study outcomes showed an overall decreased incidence of ED/EA in those groups that received dexmedetomidine versus placebo. Conclusion: Though these RCTs demonstrate statistically significant reduction of ED/EA after GA among children who receive dexmedetomidine, the clinical significance of this pharmacologic intervention is not clear. Further research is necessary to determine cost–benefit of dexmedetomidine to prevent ED/EA in children after GA and the effect of dexmedetomidine on ED/EA compared to other agents.
Weak square bracket relations forPκ(λ)
Authors: Matet Pierre
Published: December 2008

We study the partition relationthat is a weakening of the usual partition relation. Our main result asserts that if κ is an uncountable strongly compact cardinal and, thendoes not hold.
Suslin forcing and parametrized ◊ principles
Authors: Minami Hiroaki
Published: December 2008

By using finite support iteration of Suslin c.c.c forcing notions we construct several models which satisfy some ◊-like principles while other cardinal invariants are larger than ω1.
Examples of non-locality
Authors: Baldwin John T. , Shelah Saharon
Published: December 2008

We use κ-free but not Whitehead Abelian groups to construct Abstract Elementary Classes (AEC) which satisfy the amalgamation property but fail various conditions on the locality of Galois-types. We introduce the notion that an AEC admits intersections. We conclude that for AEC which admit intersections, the amalgamation property can have no positive effect on locality: there is a transformation of AEC's which preserves non-locality but takes any AEC which admits intersections to one with amalgamation. More specifically we have: Theorem 5.3. There is an AEC with amalgamation which is not (ℵ0, ℵ1)-tame but is (, ∞)-tame; Theorem 3.3. It is consistent with ZFC that there is an AEC with amalgamation which is not (≤ ℵ2, ≤ ℵ2)-compact.
Selection in the monadic theory of a countable ordinal
Authors: Rabinovich Alexander , Shomrat Amit
Published: December 2008

A monadic formula ψ(Y) is a selector for a formula φ(Y) in a structure if there exists a unique subset P of which satisfies ψ and this P also satisfies φ. We show that for every ordinal α ≥ ωω there are formulas having no selector in the structure (α, <). For α ≤ ω1, we decide which formulas have a selector in (α, <) , and construct selectors for them. We deduce the impossibility of a full generalization of the Büchi-Landweber solvability theorem from (ω, <) to (ωω, <). We state a partial extension of that theorem to all countable ordinals. To each formula we assign a selection degree which measures “how difficult it is to select”. We show that in a countable ordinal all non-selectable formulas share the same degree.
Regular ultrafilters and finite square principles
Authors: Kennedy Juliette , Shelah Saharon , Väänänen Jouko
Published: December 2008

We show that many singular cardinals λ above a strongly compact cardinal have regular ultrafilters D that violate the finite square principle introduced in [3]. For such ultrafilters D and cardinals λ there are models of size λ for which Mλ/D is not λ++-universal and elementarily equivalent models M and N of size λ for which Mλ/D and Nλ/D are non-isomorphic. The question of the existence of such ultrafilters and models was raised in [1].
A note on standard systems and ultrafilters
Authors: Engström Fredrik
Published: December 2008

Let (M,)⊨ ACA0be such that, the collection of all unbounded sets in, admits a definable complete ultrafilter and letTbe a theory extending first order arithmetic coded insuch thatMthinksTis consistent. We prove that there is an end-extensionN⊨TofMsuch that the subsets ofMcoded inNare precisely those in. As a special case we get that any Scott set with a definable ultrafilter coding a consistent theoryTextending first order arithmetic is the standard system of a recursively saturated model ofT.
Internal consistency for embedding complexity
Authors: Friedman Sy-David , Thompson Catherine
Published: December 2008

In a previous paper with M. Džamonja, class forcings were given which fixed the complexity (a universality covering number) for certain types of structures of size λ together with the value of 2λ for every regular λ. As part of a programme for examining when such global results can be true in an inner model, we build generics for these class forcings.
Scott's problem for Proper Scott sets
Authors: Gitman Victoria
Published: December 2008

Some 40 years ago, Dana Scott proved that every countable Scott set is the standard system of a model of PA. Two decades later, Knight and Nadel extended his result to Scott sets of sizeω1. Here, I show that assuming the Proper Forcing Axiom (PFA), every A-proper Scott set is the standard system of a model of PA. I define that a Scott setis proper if the quotient Boolean algebra/Fin is a proper partial order and A-proper ifis additionally arithmetically closed. I also investigate the question of the existence of proper Scott sets.
The 116 reducts of (ℚ, <, a)
Authors: Junker Markus , Ziegler Martin
Published: December 2008

This article aims to classify those reducts of expansions of (ℚ, <) by unary predicates which eliminate quantifiers, and in particular to show that, up to interdefinability, there are only finitely many for a given language. Equivalently, we wish to classify the closed subgroups of Sym(ℚ) containing the group of all automorphisms of (ℚ, <) fixing setwise certain subsets. This goal is achieved for expansions by convex predicates, yielding expansions by constants as a special case, and for the expansion by a dense, co-dense predicate. Partial results are obtained in the general setting of several dense predicates.
Classifying model-theoretic properties
Authors: Conidis Chris J.
Published: December 2008

In 2004 Csima, Hirschfeldt, Knight, and Soare [1] showed that a set A ≤T 0′ is nonlow2 if and only if A is prime bounding, i.e., for every complete atomic decidable theory T, there is a prime model computable in A. The authors presented nine seemingly unrelated predicates of a set A, and showed that they are equivalent for sets. Some of these predicates, such as prime bounding, and others involving equivalence structures and abelian p-groups come from model theory, while others involving meeting dense sets in trees and escaping a given function come from pure computability theory.

As predicates of A, the original nine properties are equivalent for sets; however, they are not equivalent in general. This article examines the (degree-theoretic) relationship between the nine properties. We show that the nine properties fall into three classes, each of which consists of several equivalent properties. We also investigate the relationship between the three classes, by determining whether or not any of the predicates in one class implies a predicate in another class.
Perfect trees and elementary embeddings
Authors: Friedman Sy-David , Thompson Katherine
Published: December 2008

An important technique in large cardinal set theory is that of extending an elementary embedding j: M → N between inner models to an elementary embedding j* : M[G] → N[G*] between generic extensions of them. This technique is crucial both in the study of large cardinal preservation and of internal consistency. In easy cases, such as when forcing to make the GCH hold while preserving a measurable cardinal (via a reverse Easton iteration of α-Cohen forcing for successor cardinals α), the generic G* is simply generated by the image of G. But in difficult cases, such as in Woodin's proof that a hypermeasurable is sufficient to obtain a failure of the GCH at a measurable, a preliminary version of G* must be constructed (possibly in a further generic extension of M[G]) and then modified to provide the required G*. In this article we use perfect trees to reduce some difficult cases to easy ones, using fusion as a substitute for distributivity. We apply our technique to provide a new proof of Woodin's theorem as well as the new result that global domination at inaccessibles (the statement that d(κ) is less than 2κ for inaccessible κ, where d(κ) is the dominating number at κ) is internally consistent, given the existence of 0#.
Strong cut-elimination in sequent calculus using Klop's ι-translation and perpetual reductions
Authors: Sørensen Morten Heine , Urzyczyn PaweŁ
Published: December 2008

There is a simple technique, due to Dragalin. for proving strong cut-elimination for intuitionistic sequent calculus, but the technique is constrained to certain choices of reduction rules, preventing equally natural alternatives. We consider such a natural, alternative set of reduction rules and show that the classical technique is inapplicable. Instead we develop another approach combining two of our favorite tools—Klop's ι-translation and perpetual reductions.

These tools are of independent interest and have proved useful in a variety of settings; it is therefore natural to investigate, as we do here, what they have to offer the field of sequent calculus.
The weak König lemma and uniform continuity
Authors: Berger Josef
Published: December 2008

We prove constructively that the weak König lemma and quantifier-free number–number choice imply that every pointwise continuous function from Cantor space into Baire space has a modulus of uniform continuity.
The modal logic of affine planes is not finitely axiomatisable
Authors: Hodkinson Ian , Hussain Altaf
Published: December 2008

We consider a modal language for affine planes, with two sorts of formulas (for points and lines) and three modal boxes. To evaluate formulas, we regard an affine plane as a Kripke frame with two sorts (points and lines) and three modal accessibility relations, namely the point-line and line-point incidence relations and the parallelism relation between lines. We show that the modal logic of affine planes in this language is not finitely axiomatisable.
On a result of Szemerédi
Authors: Jones Albin L.
Published: December 2008

We provide a short proof that if κ is a regular cardinal with κ < c, then

for any ordinal α < min{, κ}. In particular,

for any ordinal α < . This generalizes an unpublished result of E. Szemerédi that Martin's axiom implies that

for any cardinal κ with κ < c.
Construction d'un groupe dans les structures C-minimales
Authors: Maalouf Fares
Published: December 2008

We will study some aspects of the local structure of models of certain C-minimal theories. We will prove (theorem 19) that, in a sufficiently saturated C-minimal structure in which the algebraic closure has the exchange property and which is locally modular, we can construct an infinite type-definable group around any non trivial point (a term to be defined later).
On Skolemization in constructive theories
Authors: Baaz Matthias , Iemhoff Rosalie
Published: December 2008

In this paper a method for the replacement, in formulas, of strong quantifiers by functions is introduced that can be considered as an alternative to Skolemization in the setting of constructive theories. A constructive extension of intuitionistic predicate logic that captures the notions of preorder and existence is introduced and the method, orderization, is shown to be sound and complete with respect to this logic. This implies an analogue of Herbrand's theorem for intuitionistic logic. The orderization method is applied to the constructive theories of equality and groups.
Hyperimmune-free degrees and Schnorr triviality
Authors: Franklin Johanna N. Y.
Published: December 2008

We investigate the relationship between lowness for Schnorr randomness and Schnorr triviality. We show that a real is low for Schnorr randomness if and only if it is Schnorr trivial and hyperimmune free.
The degree spectra of homogeneous models
Authors: Lange Karen
Published: December 2008

Much previous study has been done on the degree spectra of prime models of a complete atomic decidable theory. Here we study the analogous questions for homogeneous models. We say a countable model has a d-basis if the types realized in are all computable and the Turing degree d can list -indices for all types realized in . We say has a d-decidable copy if there exists a model ≅ such that the elementary diagram of is d-computable. Goncharov, Millar, and Peretyat'kin independently showed there exists a homogeneous with a 0-basis but no decidable copy.

We prove that any homogeneous with a 0′-basis has a low decidable copy. This implies Csima's analogous result for prime models. In the case where all types of the theory T are computable and is a homogeneous model with a 0-basis, we show has copies decidable in every nonzero degree. A degree d is 0-homogeneous bounding if any automorphically nontrivial homogeneous with a 0-basis has a d-decidable copy. We show that the nonlow2 degrees are 0-homogeneous bounding.
Aronszajn lines and the club filter
Authors: Moore Justin Tatch
Published: December 2008

The purpose of this note is to demonstrate that a weak form of club guessing on ω1implies the existence of an Aronszajn line with no Countryman suborders. An immediate consequence is that the existence of a five element basis for the uncountable linear orders does not follow from the forcing axiom for ω-proper forcings.
Motives for perfect PAC fields with pro-cyclic Galois group
Authors: Halupczok Immanuel
Published: December 2008

Denef and Loeser denned a map from the Grothendieck ring of sets definable in pseudo-finite fields to the Grothendieck ring of Chow motives, thus enabling to apply any cohomological invariant to these sets. We generalize this to perfect, pseudo algebraically closed fields with pro-cyclic Galois group.

In addition, we define some maps between different Grothendieck rings of definable sets which provide additional information, not contained in the associated motive. In particular we infer that the map of Denef-Loeser is not injective.
Examining Fragments of the Quantified Propositional Calculus
Authors: Perron Steven
Published: December 2008

When restricted to proving formulas, the quantified propositional proof system is closely related to the theorems of Buss's theory . Namely, has polynomial-size proofs of the translations of theorems of , and proves that is sound. However, little is known about when proving more complex formulas. In this paper, we prove a witnessing theorem for similar in style to the KPT witnessing theorem for . This witnessing theorem is then used to show that proves is sound with respect to formulas. Note that unless the polynomial-time hierarchy collapses is the weakest theory in the S2 hierarchy for which this is true. The witnessing theorem is also used to show that is p-equivalent to a quantified version of extended-Frege for prenex formulas. This is followed by a proof that Gi, p-simulates with respect to all quantified propositional formulas. We finish by proving that S2 can be axiomatized by plus axioms stating that the cut-free version of is sound. All together this shows that the connection between and does not extend to more complex formulas.
Closed Fragments of Provability Logics of Constructive Theories
Authors: Visser Albert
Published: December 2008

In this paper we give a new proof of the characterization of the closed fragment of the provability logic of Heyting's Arithmetic. We also provide a characterization of the closed fragment of the provability logic of Heyting's Arithmetic plus Markov's Principle and Heyting's Arithmetic plus Primitive Recursive Markov's Principle.
η-representation of sets and degrees
Authors: Harris Kenneth
Published: December 2008

We show that a set has an η-representation in a linear order if and only if it is the range of a 0′-computable limitwise monotonic function. We also construct a Δ3 Turing degree for which no set in that degree has a strong η-representation, answering a question posed by Downey.
Unary primitive recursive functions
Authors: Severin Daniel E.
Published: December 2008

In this article, we study some new characterizations of primitive recursive functions based on restricted forms of primitive recursion, improving the pioneering work of R. M. Robinson and M. D. Gladstone. We reduce certain recursion schemes (mixed/pure iteration without parameters) and we characterize one-argument primitive recursive functions as the closure under substitution and iteration of certain optimal sets.
Measurable chromatic numbers
Authors: Miller Benjamin D.
Published: December 2008

We show that if add(null) = c, then the globally Baire and universally measurable chromatic numbers of the graph of any Borel function on a Polish space are equal and at most three. In particular, this holds for the graph of the unilateral shift on [ℕ]ℕ, although its Borel chromatic number is ℵ0. We also show that if add(null) = c, then the universally measurable chromatic number of every treeing of a measure amenable equivalence relation is at most three. In particular, this holds for “the” minimum analytic graph with uncountable Borel (and Baire measurable) chromatic number. In contrast, we show that for all κ Є6 (2, 3…..ℵ0, c), there is a treeing of E0 with Borel and Baire measurable chromatic number κ. Finally, we use a Glimm–Effros style dichotomy theorem to show that every basis for a non-empty initial segment of the class of graphs of Borel functions of Borel chromatic number at least three contains a copy of (ℝ<ℕ, ⊇).
Analytic and coanalytic families of almost disjoint functions
Authors: Kastermans Bart , Juris Steprāns  , Zhang Yi
Published: December 2008

Ifis an analytic family of pairwise eventually different functions then the following strong maximality condition fails: For any countable, no member of which is covered by finitely many functions from, there issuch that for allthere are infinitely many integersksuch thatf(k) = h(k). However ifV = Lthen there exists a coanalytic family of pairwise eventually different functions satisfying this strong maximality condition.
An example of a polish group
Authors: Malicki Maciej
Published: December 2008

We construct a non-discrete Polish group none of whose non-discrete subgroups admits a complete left-invariant metric.
A la recherche de la definition de la complexite d'espace pour le calcul des polynomes a la maniere de Valiant
Authors: Poizat Bruno
Published: December 2008

Nous définissons une classe de suites de polynômes, calculés par des circuits de complexité polynomiale comprenant des additions, des soustractions. des multiplications et des sommations de Valiant. Nous montrons que cette classe est close pour la prise de la fonction-coefficient. définie au paragraphe 3 de cet article; nous en déduisons l'existence d'un circuit de complexité 72.n2, calculant le coefficient binomial de deux nombres de n chiffres, donnés en base 2. Il est par ailleurs facile de construire un circuit de complexité 17.n + 2 calculant la factorielle d'un nombre de n chiffres. La présence de 2.n sommations d'effet exponentiel dans chacun de ces circuits en affecte gravement l'intérêt pratique. II est peu probable, ou du moins peu souhaitable. qu'on puisse éliminer ces sommations sans explosion, car cela provoquerait la catastrophe cryptographique que redoutent tous les banquiers; néanmoins, nous ne savons pas séparer la classe définie ici de celle des suites de polynômes calculables en un nombre polynomial d'opérations arithmétiques. Cela n'a rien de surprenant, vu la très grande affinité qu'elle a avec la classe PSPACE: nous montrons en effet que cette classe est identique à la classe VPSPACE, définie antérieurement par Koiran et Perifel, qui apparaît ici sous une forme bien plus maniable que l'originale.
P-hierarchy on βω
Authors: Starosolski Andrzej
Published: December 2008

We classify ultrafilters on ω with respect to sequential contours (see [4]. [5]) of different ranks. In this way we obtain an ω1 sequence of disjoint classes. We prove that non-emptiness of for successor α ≥ 2 is equivalent to the existence of P-point. We investigate relations between P-hierarchy and ordinal ultrafilters (introduced by J. E. Baumgartner in [1]). we prove that it is relatively consistent with ZFC that the successor classes (for α ≥ 2) of P-hierarchy and ordinal ultrafilters intersect but are not the same.
Strongly unfoldable cardinals made indestructible
Authors: Johnstone Thomas A.
Published: December 2008

I provide indestructibility results for large cardinals consistent with V = L, such as weakly compact, indescribable and strongly unfoldable cardinals. The Main Theorem shows that any strongly unfoldable cardinal κ can be made indestructible by <κ-closed, κ-proper forcing. This class of posets includes for instance all <κ-closed posets that are either κ−-c.c. or <κ-strategically closed as well as finite iterations of such posets. Since strongly unfoldable cardinals strengthen both indescribable and weakly compact cardinals, the Main Theorem therefore makes these two large cardinal notions similarly indestructible. Finally. I apply the Main Theorem to obtain a class forcing extension preserving all strongly unfoldable cardinals in which every strongly unfoldable cardinal κ is indestructible by <κ-closed, κ-proper forcing.
There exists an uncountable set of pretabular extensions of the relevant logic R and each logic of this set is generated by a variety of finite height
Authors: Swirydowicz Kazimierz
Published: December 2008

In Handbook of Philosophical Logic M. Dunn formulated a problem of describing pretabular extensions of relevant logics (cf. M. Dunn [1984], p. 211; M. Dunn, G. Restall [2002], p. 79). The main result of this paper is described in the title.
Combinatorial images of sets of reals and semifilter trichotomy
Authors: Tsaban Boaz , Zdomskyy Lyubomyr
Published: December 2008

Using a dictionary translating a variety of classical and modern covering properties into combinatorial properties of continuous images, we get a simple way to understand the interrelations between these properties in ZFC and in the realm of the trichotomy axiom for upward closed families of sets of natural numbers. While it is now known that the answer to the Hurewicz 1927 problem is positive, it is shown here that semifilter trichotomy implies a negative answer to a slightly stronger form of this problem.
Splitting families and the Noetherian type of βω / ω
Authors: Milovich David
Published: December 2008

Extending some results of Malykhin, we prove several independence results about base properties of βω / ω and its powers, especially the Noetherian type Nt(βω / ω), the least κ for which βω / ω has a base that is κ-like with respect to containment. For example, Nt(βω / ω) is at least s, but can consistently be ω1, c, c+, or strictly between ω1 and c. Nt(βω / ω) is also consistently less than the additivity of the meager ideal. Nt(βω / ω) is closely related to the existence of special kinds of splitting families.
Completeness and incompleteness for intuitionistic logic
Authors: Mccarty Charles
Published: December 2008

We call a logicregularfor a semantics when the satisfaction predicate for at least one of its nontheorems is closed under double negation. Such intuitionistic theories as second-order Heyting arithmeticHASand the intuitionistic set theoryIZFprove completeness for no regular logics, no matter how simple or complicated. Any extensions of those theories proving completeness for regular logics are classical, i.e., they derive thetertium non datur. When an intuitionistic metatheory features anticlassical principles or recognizes that a logic regular for a semantics is nonclassical, it proves explicitly that the logic is incomplete with respect to that semantics. Logics regular relative to Tarski, Beth and Kripke semantics form a large collection that includes propositional and predicate intuitionistic, intermediate and classical logics. These results are corollaries of a single theorem. A variant of its proof yields a generalization of the Gödel-Kreisel Theorem linking weak completeness for intuitionistic predicate logic to Markov's Principle.
Borel complexity of isomorphism between quotient Boolean algebras
Authors: Gao Su , Oliver Michael Ray
Published: December 2008

In response to a question of Farah, “How many Boolean algebras are there?” [Far04], one of us (Oliver) proved that there are continuum-many nonisomorphic Boolean algebras of the form with I a Borel ideal on the natural numbers, and in fact that this result could be improved simultaneously in two directions:

(i) “Borel ideal” may be improved to “analytic P-ideal”

(ii) “continuum-many” may be improved to “E0-many”; that is, E0 is Borel reducible to the isomorphism relation on quotients by analytic P-ideals.

See [Oli04].

In [AdKechOO], Adams and Kechris showed that the relation of equality on Borel sets (and therefore, any Borel equivalence relation whatsoever) is Borel reducible to the equivalence relation of Borel bireducibility. (In somewhat finer terms, they showed that the partial order of inclusion on Borel sets is Borel reducible to the quasi-order of Borel reducibility.) Their technique was to find a collection of, in some sense, strongly mutually ergodic equivalence relations, indexed by reals, and then assign to each Borel set B a sort of “direct sum” of the equivalence relations corresponding to the reals in B. Then if B1, ⊆ B2 it was easy to see that the equivalence relation thus induced by B1 was Borel reducible to the one induced by B2, whereas in the opposite case, taking x to be some element of B / B2, it was possible to show that the equivalence relation corresponding to x, which was part of the equivalence relation induced by B1, was not Borel reducible to the equivalence relation corresponding to B2.
Π10 classes with complex elements
Authors: Binns Stephen
Published: December 2008

An infinite binary sequence is complex if the Kolmogorov complexity of its initial segments is bounded below by a computable function. We prove that a class P contains a complex element if and only if it contains a wtt-cover for the Cantor set. That is, if and only if for every Y ⊆ ω there is an X in P such that X ≥wttY. We show that this is also equivalent to the class's being large in some sense. We give an example of how this result can be used in the study of scattered linear orders.