Highly Polarized Optically-Selected BL Lacertae Objects

Observations of candidate BL Lacertae objects spectroscopically selected from the Sloan Digital Sky Survey (SDSS) reveal a large fraction with high polarization (P > 3%). This result confirms that synchrotron radiation makes an important contribution to the observed optical continuum for most objects in the sample. The SDSS sample can be divided into separate categories, with objects of undetermined redshift generally having the highest optical polarization. Polarization as high as 23% and the lack of spectral features suggests that the synchrotron continuum completely dominates the spectra of these sources. The mean polarization levels observed for objects having measured redshifts is much lower, with the maximum observed polarization for this group being ~10%. The lower polarizations of these objects are reminiscent of the less spectacular polarization levels shown by BL Lac objects discovered in X-ray surveys. We find no SDSS BL Lac candidates at z > 1 with P > 3%, calling their classification as BL Lac objects into question. In addition, the existence of radio-quiet BL Lac objects is not verified since none of 10 potentially radio-weak BL Lac candidates observed are highly polarized. Regardless of whether the high-redshift and radio-weak objects are included in this optical sample, the overall levels of polarization observed are intermediate between those seen for X-ray and radio-selected BL Lac objects.Comment: 9 pages, 3 figures, 2 table

Psychiatric disorders and risk of transition to chronicity in men with first onset low back pain

OBJECTIVE: To assess whether pre-existing psychiatric diagnoses increase the likelihood of transitioning from sub-acute to chronic back pain. DESIGN: Prospective cohort study. METHODS: Men (N = 140) experiencing a first onset of low back pain (LBP) were examined for lifetime psychiatric disorders approximately 8 weeks post pain-onset using the Diagnostic Interview Schedule (DIS-III-R), then re-evaluated at 6 months after pain onset to determine who did or did not progress to pain chronicity. OUTCOME MEASURE: Transition to chronic pain and disability was based on 6-month self-report measures of pain intensity and perceived disability. RESULTS: Men with a pre-pain lifetime diagnosis of major depressive disorder had 5 times greater risk of transitioning to chronic LBP (odds ratio [OR] = 4.99; 95% confidence interval [CI] 1.49-16.76). Increased risk was also associated with a pre-pain lifetime diagnosis of generalized anxiety (OR = 2.45; 95% CI 1.06-5.68), post-traumatic stress (OR = 3.23; 95% CI 1.11-9.44), and with current nicotine dependence (OR = 2.49; 95% CI 1.15-5.40). There were no statistically significant effects for abuse or dependence of alcohol or other psychoactive substances. DISCUSSION: Lifetime history of major depression or a major anxiety disorder may represent potential psychosocial yellow flags for the transition to chronicity in men with first-onset LBP. Screening for lifetime depressive or anxiety disorders may identify individuals at higher risk, who may benefit from referral for more intensive rehabilitation

Mycobacterium paratuberculosis is recognized by Toll-like receptors and NOD2.

Contains fulltext : 53634.pdf (publisher's version ) (Open Access)Mycobacterium paratuberculosis has been suggested to be involved in the pathogenesis of Crohn's disease (CD). The importance of microorganisms in CD is supported by the association of CD with mutations in the intracellular pathogen recognition receptor (PRR) nucleotide-binding oligomerization domain 2 (NOD2). The aim of this study is to investigate the PRR involved in the recognition of M. paratuberculosis. Methods used include in vitro stimulation of transfected cell lines, murine macrophages, and human PBMC. M. paratuberculosis stimulated human TLR2 (hTLR2)-Chinese hamster ovary (CHO) cells predominantly and hTLR4-CHO cells modestly. Macrophages from TLR2 and TLR4 knockout mice produced less cytokines compared with controls after stimulation with M. paratuberculosis. TLR4 inhibition in human PBMC reduced cytokine production only after stimulation with live M. paratuberculosis. TLR-induced TNF-alpha, IL-1beta, and IL-10 production is mediated through MyD88, whereas Toll-IL-1R domain-containing adaptor inducing IFN-beta (TRIF) promoted the release of IL-1beta. hNOD2-human embryo kidney (HEK) cells, but not hNOD1-HEK cells, responded to stimulation with M. paratuberculosis. PBMC of individuals homozygous for the 3020insC NOD2 mutation showed a 70% defective cytokine response after stimulation with M. paratuberculosis. These results demonstrate that TLR2, TLR4, and NOD2 are involved in the recognition of M. paratuberculosis by the innate immune system

Cyclical variation in the profit-concentration relationship

Profit-concentration relationships, cyclical profit analyses,