Magnetic Order in the 2D Heavy-Fermion System CePt2In7 studied by muSR

The low-temperature microscopic magnetic properties of the quasi-2D heavyfermion compound, CePt2In7 are investigated by using a positive muon-spin rotation and relaxation (?muSR) technique. Clear evidence for the formation of a commensurate antiferromagnetic order below TN=5.40 K is presented. The magnetic order parameter is shown to fit well to a modified BSC gap-energy function in a strong-coupling scenario.Comment: Accepted in Journal of Physics: Conference Series (2014

Sick-leave track record and other potential predictors of a disability pension. A population based study of 8,218 men and women followed for 16 years

<p>Abstract</p> <p>Background</p> <p>A number of previous studies have investigated various predictors for being granted a disability pension. The aim of this study was to test the efficacy of sick-leave track record as a predictor of being granted a disability pension in a large dataset based on subjects sampled from the general population and followed for a long time.</p> <p>Methods</p> <p>Data from five ongoing population-based Swedish studies was used, supplemented with data on all compensated sick leave periods, disability pensions granted, and vital status, obtained from official registers. The data set included 8,218 men and women followed for 16 years, generated 109,369 person years of observation and 97,160 sickness spells. Various measures of days of sick leave during follow up were used as independent variables and disability pension grant was used as outcome.</p> <p>Results</p> <p>There was a strong relationship between individual sickness spell duration and annual cumulative days of sick leave on the one hand and being granted a disability pension on the other, among both men and women, after adjustment for the effects of marital status, education, household size, smoking habits, geographical area and calendar time period, a proxy for position in the business cycle. The interval between sickness spells showed a corresponding inverse relationship. Of all the variables studied, the number of days of sick leave per year was the most powerful predictor of a disability pension. For both men and women 245 annual sick leave days were needed to reach a 50% probability of transition to disability. The independent variables, taken together, explained 96% of the variation in disability pension grantings.</p> <p>Conclusion</p> <p>The sick-leave track record was the most important predictor of the probability of being granted a disability pension in this study, even when the influences of other variables affecting the outcome were taken into account.</p

Spectroscopic evidence for preformed Cooper pairs in the pseudogap phase of cuprates

Angle-resolved photoemission on underdoped La$_{1.895}$Sr$_{0.105}$CuO$_4$ reveals that in the pseudogap phase, the dispersion has two branches located above and below the Fermi level with a minimum at the Fermi momentum. This is characteristic of the Bogoliubov dispersion in the superconducting state. We also observe that the superconducting and pseudogaps have the same d-wave form with the same amplitude. Our observations provide direct evidence for preformed Cooper pairs, implying that the pseudogap phase is a precursor to superconductivity

The dual string sigma-model of the SU_q(3) sector

In four-dimensional N=4 super Yang-Mills (SYM) the SU(3) sub-sector spanned by purely holomorphic fields is isomorphic to the corresponding mixed one spanned by both holomorphic and antiholomorphic fields. This is no longer the case when one considers the marginally deformed N=4 SYM. The mixed SU(3) sector marginally deformed by a complex parameter beta, i.e. SU_q(3) with q=e^{2 i\pi\beta}, has been shown to be integrable at one-loop hep-th/0703150, while it is not the case for the corresponding purely holomorphic one. Moreover, the marginally deformed N=4 SYM also has a gravity dual constructed by Lunin and Maldacena in hep-th/0502086. However, the mixed SU_q(3) sector has not been studied from the supergravity point of view. Hence in this note, for the case of purely imaginary marginal $\beta$-deformations, we compute the superstring SU_q(3) \sigma-model in the fast spinning string limit and show that, for rational spinning strings, it reproduces the energy computed via Bethe equations.Comment: 20 page

Multiple phenotypic changes in mice after knockout of the B3gnt5 gene, encoding Lc3 synthase--a key enzyme in lacto-neolacto ganglioside synthesis

<p>Abstract</p> <p>Background</p> <p>Ganglioside biosynthesis occurs through a multi-enzymatic pathway which at the lactosylceramide step is branched into several biosynthetic series. Lc3 synthase utilizes a variety of galactose-terminated glycolipids as acceptors by establishing a glycosidic bond in the beta-1,3-linkage to GlcNaAc to extend the lacto- and neolacto-series gangliosides. In order to examine the lacto-series ganglioside functions in mice, we used gene knockout technology to generate Lc3 synthase gene <it>B3gnt5-</it>deficient mice by two different strategies and compared the phenotypes of the two null mouse groups with each other and with their wild-type counterparts.</p> <p>Results</p> <p><it>B3gnt5 </it>gene knockout mutant mice appeared normal in the embryonic stage and, if they survived delivery, remained normal during early life. However, about 9% developed early-stage growth retardation, 11% died postnatally in less than 2 months, and adults tended to die in 5-15 months, demonstrating splenomegaly and notably enlarged lymph nodes. Without lacto-neolacto series gangliosides, both homozygous and heterozygous mice gradually displayed fur loss or obesity, and breeding mice demonstrated reproductive defects. Furthermore, <it>B3gnt5 </it>gene knockout disrupted the functional integrity of B cells, as manifested by a decrease in B-cell numbers in the spleen, germinal center disappearance, and less efficiency to proliferate in hybridoma fusion.</p> <p>Conclusions</p> <p>These novel results demonstrate unequivocally that lacto-neolacto series gangliosides are essential to multiple physiological functions, especially the control of reproductive output, and spleen B-cell abnormality. We also report the generation of anti-IgG response against the lacto-series gangliosides 3'-isoLM1 and 3',6'-isoLD1.</p

High-throughput analysis of sulfatides in cerebrospinal fluid using automated extraction and UPLC-MS/MS

Sulfatides (STs) are a group of glycosphingolipids that are highly expressed in brain. Due to their importance for normal brain function and their potential involvement in neurological diseases, development of accurate and sensitive methods for their determination is needed. Here we describe a high-throughput oriented and quantitative method for the determination of STs in cerebrospinal fluid (CSF). The STs were extracted using a fully automated liquid/liquid extraction method and quantified using ultra-performance liquid chromatography coupled to tandem mass spectrometry. With the high sensitivity of the developed method, quantification of 20 ST species from only 100 μl of CSF was performed. Validation of the method showed that the STs were extracted with high recovery (90%) and could be determined with low inter- and intra-day variation. Our method was applied to a patient cohort of subjects with an Alzheimer’s disease biomarker profile. Although the total ST levels were unaltered compared with an age-matched control group, we show that the ratio of hydroxylated/nonhydroxylated STs was increased in the patient cohort. In conclusion, we believe that the fast, sensitive, and accurate method described in this study is a powerful new tool for the determination of STs in clinical as well as preclinical settings

Four-loop anomalous dimensions in Leigh-Strassler deformations

We determine the scalar part of the four-loop chiral dilatation operator for Leigh-Strassler deformations of N=4 super Yang-Mills. This is sufficient to find the four-loop anomalous dimensions for operators in closed scalar subsectors. This includes the SU(2) subsector of the (complex) beta-deformation, where we explicitly compute the anomalous dimension for operators with a single impurity. It also includes the "3-string null" operators of the cubic Leigh-Strassler deformation. Our four-loop results show that the rational part of the anomalous dimension is consistent with a conjecture made in arXiv:1108.1583 based on the three-loop result of arXiv:1008.3351 and the N=4 magnon dispersion relation. Here we find additional zeta(3) terms.Comment: Latex, feynmp, 21 page