High intermodulation gain in a micromechanical Duffing resonator

In this work we use a micromechanical resonator to experimentally study small signal amplification near the onset of Duffing bistability. The device consists of a PdAu beam serving as a micromechanical resonator excited by an adjacent gate electrode. A large pump signal drives the resonator near the onset of bistability, enabling amplification of small signals in a narrow bandwidth. To first order, the amplification is inversely proportional to the frequency difference between the pump and signal. We estimate the gain to be about 15dB for our device

Dust Formation and He II 4686 emission in the Dense Shell of the Peculiar Type Ib Supernova 2006jc

We present evidence for the formation of dust grains in an unusual Type Ib SN based on late-time spectra of SN 2006jc. The progenitor suffered an LBV-like outburst just 2 yr earlier, and we propose that the dust formation is a consequence of the SN blast wave overtaking that LBV-like shell. The key evidence for dust formation is (a) the appearance of a red/near-IR continuum source fit by 1600 K graphite grains, and (b) fading of the redshifted sides of He I emission lines, yielding progressively more asymmetric blueshifted lines as dust obscures receding material. This provides the strongest case yet for dust formation in any SN Ib/c. Both developments occurred between 51 and 75 d after peak, while other SNe observed to form dust did so after a few hundred days. Geometric considerations indicate that dust formed in the dense swept-up shell between the forward and reverse shocks, and not in the freely expanding SN ejecta. Rapid cooling leading to dust formation may have been aided by extremely high shell densities, as indicated by He I line ratios. The brief epoch of dust formation is accompanied by He II 4686 emission and enhanced X-ray emission. These clues suggest that the unusual dust formation in this object was not due to properties of the SN itself, but instead -- like most peculiarities of SN 2006jc -- was a consequence of the dense environment created by an LBV-like eruption 2 yr before the SN.Comment: ApJ, accepted. added some discussion and 2 figures, better title, conclusions same as previous version. 12 pages, 4 color fig

Metabolomics reveals novel insight on dormancy of aquatic invertebrate encysted embryos

Numerous aquatic invertebrates survive harsh environments by displaying dormancy as encysted embryos. This study aimed at determining whether metabolomics could provide molecular insight to explain the “dormancy syndrome” by highlighting functional pathways and metabolites, hence offering a novel comprehensive molecular view of dormancy. We compared the metabolome of morphologically distinct dormant encysted embryos (resting eggs) and non-dormant embryos (amictic eggs) of a rotifer (Brachionus plicatilis). Metabolome profiling revealed ~5,000 features, 1,079 of which were annotated. Most of the features were represented at significantly higher levels in non-dormant than dormant embryos. A large number of features was assigned to putative functional pathways indicating novel differences between dormant and non-dormant states. These include features associated with glycolysis, the TCA and urea cycles, amino acid, purine and pyrimidine metabolism. Interestingly, ATP, nucleobases, cyclic nucleotides, thymidine and uracil, were not detected in dormant resting eggs, suggesting an impairment of response to environmental and internal cues, cessation of DNA synthesis, transcription and plausibly translation in the dormant embryos. The levels of trehalose or its analogues, with a role in survival under desiccation conditions, were higher in resting eggs. In conclusion, the current study highlights metabolomics as a major analytical tool to functionally compare dormancy across species.Animal science

Statins in Candidemia: clinical outcomes from a matched cohort study

<p>Abstract</p> <p>Background</p> <p>HMG CoA reductase inhibitors (statins) in patients with bacteremic sepsis have shown significant survival benefits in several studies. There is no data on the effect of statins in candidemic patients, however in-vitro models suggest that statins interfere with ergesterol formation in the wall of yeasts.</p> <p>Methods</p> <p>This retrospective matched- cohort study from 1/2003 to 12/2006 evaluated the effects of statins on patients with candidemia within intensive care units. Statin-users had candidemia as a cause of their systemic inflammatory response and were on statins throughout their antifungal therapy, while non-statin users were matched based on age +/- 5 years and co-morbid factors. Primary analysis was 30-day survival or discharge using bivariable comparisons. Multivariable comparisons were completed using conditional logistic regression. All variables with a p-value less than 0.10 in the bivariable comparisons were considered for inclusion in the conditional logistic model.</p> <p>Results</p> <p>There were 15 statin-users and 30 non-statin users that met inclusion criteria, all with similar demographics and co-morbid conditions except the statin group had more coronary artery disease (P < 0.01) and peripheral vascular disease (P = 0.03) and lower median APCAHE II scores (14.6 vs 17, p = 0.03). There were no differences in duration of candidemia, antifungal therapy or <it>Candida </it>species between the groups. Statins were associated with lower mortality on bivariable (OR 0.09, 95% CI 0.11-0.75, p = 0.03) and multivariable (OR 0.22, 95% CI 0.02-2.4, p = 0.21) analyses compared to controls; although, in the latter the protective effect lacked statistical signficance.</p> <p>Conclusion</p> <p>In our small, single-center matched-cohort study, statins may provide a survival benefit in candidemia, however further studies are warranted to validate and further explore this association.</p

Foreign policy and globalization theory: The case of Israel

Since the early 1990s, international relations has witnessed a stimulating debate on globalization. This debate laid the foundations for globalization theory (GT), providing the tools for an empirical examination of the globalization of multiple activities: from politics and organized violence, to finance, trade and production, through culture and environmental degradation. However, examination of what appear to be the best-known works on globalization reveals that foreign policy has been virtually excluded from GT. In this context, based on what is described here as a synergistic transformationalist approach (STA) to globalization, I provide a critique of GT. The critique is geared towards examining why foreign policy hitherto has been overlooked by contemporary GT. I expose the problems this generates and address them by exploring how STA enables GT to incorporate foreign policy. I use the case of Israel heuristically to elicit how incorporating foreign policy into GT may provide a better understanding of the relationship between foreign policy and globalization. Three themes are highlighted: the role of foreign policy in inducing and reproducing globalization; determining the mutually constitutive relationship between globalization and the state; and shaping the interfacing between international politics and globalization