Gravitational Waves in Bianchi Type-I Universes I: The Classical Theory

The propagation of classical gravitational waves in Bianchi Type-I universes is studied. We find that gravitational waves in Bianchi Type-I universes are not equivalent to two minimally coupled massless scalar fields as it is for the Robertson-Walker universe. Due to its tensorial nature, the gravitational wave is much more sensitive to the anisotropy of the spacetime than the scalar field is and it gains an effective mass term. Moreover, we find a coupling between the two polarization states of the gravitational wave which is also not present in the Robertson-Walker universe.Comment: 34 papers, written in ReVTeX, submitted to Physical Review

The Influence of an Adsorbate Layer on Adatom Diffusion and Island Nucleation: Fe on Si(111)-√3 x √3-Au

Using scanning tunneling microscopy, the influence of a thin Au layer on the diffusion of Fe adatoms and the subsequent island nucleation on a Si(111) surface is investigated. The adsorbate induces thestructure that increases the surface mobility of subsequently deposited Fe atoms, resulting in the formation well-defined nanoclusters. Surprisingly, the domain walls—inherent to the reconstruction—do not influence the surface diffusion, which demonstrates that the passivation is of much more importance for the self-assembly than the surface corrugation. Using the decoupling of the diffusion and nucleationonthe surface and the reactionwiththe surface and conventional nucleation theory, the activation energy for surface diffusionEd = 0.61 eV and the critical cluster sizei = 3 are determined, which reveal the microscopic details of the diffusion and nucleation processes

Does the thermal spike affect low-energy ion-induced interfacial mixing?

Molecular dynamics simulations have been used to obtain the three-dimensional distribution of interfacial mixing and cascade defects in Ti/Pt multilayer system due to single 1 keV $Ar^+$ impacts at grazing angle of incidence. The Ti/Pt system was chosen because of its relatively high heat of mixing in the binary alloy and therefore a suitable candidate for testing the effect of heat of mixing on ion-beam mixing. However, the calculated mixing profile is not sensitive to the heat of mixing. Therefore the thermal spike model of mixing is not fully supported under these irradiation conditions. Instead we found that the majority of mixing occurs after the thermal spike during the relaxation process. These conclusions are supported by liquid, vacancy as well as adatom analysis. The interfacial mixing is in various aspects anomalous in this system: the time evolution of mixing is leading to a phase delay for Ti mixing, and Pt exhibits an unexpected double peaked mixing evolution. The reasons to these effects are discussed.Comment: 7 pages, 12 figures, Nucl. Instr. Meth. B211, 524. (2003

Prognosis and course of work-participation in patients with chronic non-specific low back pain: a 12-month follow-up cohort study

AbstractOBJECTIVE:To investigate the clinical course of, and prognostic factors for, work-participation in patients with chronic non-specific low back pain.METHODS:A total of 1,608 patients with chronic non-specific low back pain received a multidisciplinary therapy and were evaluated at baseline and 2-, 5- and 12-month follow-ups. Recovery was defined as absolute recovery if the patient worked 90% of his contract hours at follow-up. Potential factors were identified using multivariable logistic regression analysis.RESULTS:Patients reported a mean increase in work-participation from 38% at baseline to 82% after 12 months. Prognostic factors for ≥ 90% work-participation at 5 months were being married (odds ratio (OR) 1.72 (95% confidence interval (95% CI) 1.12-2.65)), male (OR 1.99 (95% CI 1.24-3.20)), a higher score on disability (OR 1.00 (95% CI 0.997-1.02)) and physical component scale (Short-Form 36 (SF-36)) (OR 1.05 (95% CI 1.02-1.07)), previous rehabilitation (OR 1.85 (95% CI 1.14-2.98)), not receiving sickness benefits (OR 0.52 (95% CI 0.24-1.10)) and more work-participation (OR 4.86 (95% CI 2.35-10.04)). More work-participation (OR 5.22 (95% CI 3.47-7.85)) and male sex (OR 1.79 (95% CI 1.25-2.55)) were also prognostic factors at 12-month follow-up.CONCLUSION:At 12 months 52% of patients reported ≥ 90% work-participation. The strongest prognostic factor was more work-participation at baseline for the recovery of chronic non-specific low back pai

Price Effects of Energy-Efficient Technologies: A Study of Residential Demand for Heating and Cooling

This paper applies a mixed engineering and econometric model to empirically analyze behavioral interaction with new energy-efficient appliances and thermal improvements. The hypothesis is that energy efficient technologies lower the effective price of the services they provide and consequently reduce electricity consumption by smaller amounts than would be anticipated in engineering estimates. The approach incorporates prior engineering knowledge about the interactive effects of weather, appliance efficiencies, and thermal integrity of dwellings to explore treatment groups in an experiment conducted in Florida

Transient deSUMOylation of IRF2BP proteins controls early transcription in EGFR signaling

Molecular switches are essential modules in signaling networksand transcriptional reprogramming. Here, we describe a role forsmall ubiquitin-related modifier SUMO as a molecular switch inepidermal growth factor receptor (EGFR) signaling. Using quantita-tive mass spectrometry, we compare the endogenous SUMOproteomes of HeLa cells before and after EGF stimulation. Thereby,we identify a small group of transcriptional coregulators includingIRF2BP1, IRF2BP2, and IRF2BPL as novel players in EGFR signaling.Comparison of cells expressing wild type or SUMOylation-deficientIRF2BP1indicates that transient deSUMOylation of IRF2BP proteinsis important for appropriate expression of immediate early genesincludingdual specificity phosphatase1(DUSP1, MKP-1) and thetranscription factor ATF3. We find that IRF2BP1is a repressor,whose transient deSUMOylation on the DUSP1promoter allows—and whose timely reSUMOylation restricts—DUSP1transcription.Our work thus provides a paradigm how comparative SUMOproteome analyses serve to reveal novel regulators in signal trans-duction and transcription

Prediction of parturition in Holstein dairy cattle using electronic data loggers

The objective of the present study was to assess the effect of parturition on behavioral activity [steps, standing time, lying time, lying bouts (LB), and duration of LB] 4 d before calving using electronic data loggers. Animals (n = 132) from 3 herds were housed in similar freestall barns using a prepartum pen 21 d before the expected calving date and were moved into a contiguous individual maternity pen for parturition. Electronic data loggers were placed on a hind leg of prepartum heifers (heifers, n = 33) and cows (cows, n = 99) at 7 ± 3 d before the expected calving date and removed at 14 ± 3 d in milk. Calving ease (scale 1–4), parity, calving date and time, and stillbirth (born dead or died within 24 h) were recorded. The number of steps (no./d), standing time (min/d), lying time (min/d), number of LB (no./d), and duration of LB (min/b) were recorded. Data were analyzed using MIXED procedures of SAS, adjusting for the herd effect. Only cows experiencing unassisted births (calving ease = 1) were included in the study. An activity index was developed to predict calving time. Heifers and cows with unassisted births had significantly higher number of steps and longer standing time, decreased lying time, and more LB of shorter duration 24 h before calving compared with d −4, −3, and −2. Additionally, the number of LB increased as both heifers and cows approached labor starting on d −2 and peaked at the day of calving. The time since the activity index increased over 50% to parturition did not differ between heifers and cows, and the activity index revealed the shift in activity on average 6 h 14 min (range from 2 h to 14 h 15 min) before calf birth. This study provided evidence that heifers and cows approaching parturition showed a similar, but distinct, behavioral pattern that can be observed on average 6 h before calf birth. The potential benefits of electronic data loggers as predictors of parturition along with proactive management practices should improve the overall survival and welfare of both the dam and calf