Commodity Price Shocks and the Business Cycle: Structural Evidence for the U.S.

This paper develops a 9-dimensional SVAR to investigate the sources of the U.S. business cycle. We extend the standard set of identified shocks to include unexpected changes in commodity prices. Our main result is that commodity price shocks are a very important driving force of macroeconomic fluctuations, second only to investment-specific technology shocks. In particular, we find that commodity price shocks explain a large share of cyclical movements in inflation. Neutral technology shocks and monetary policy shocks seem less relevant at business cycle frequencies. The impulse response dynamics provide support for medium-scale DSGE models, but not for strong price rigidities.business cycles, commodity price shocks, structural VAR

Commodity Price Shocks and the Business Cycle: Structural Evidence for the U.S.

This paper develops a 9-dimensional SVAR to investigate the sources of the U.S. business cycle. We extend the standard set of identified shocks to include unexpected changes in commodity prices. Our main result is that commodity price shocks are a very important driving force of macroeconomic fluctuations, second only to investment-specific technology shocks. In particular, we find that commodity price shocks explain a large share of cyclical movements in inflation. Neutral technology shocks and monetary policy shocks seem less relevant at business cycle frequencies. The impulse response dynamics provide support for medium-scale DSGE models, but not for strong price rigidities.business cycles, commodity price shocks, structural VAR

Geometric Bogomolov conjecture for abelian varieties and some results for those with some degeneration (with an appendix by Walter Gubler: The minimal dimension of a canonical measure)

In this paper, we formulate the geometric Bogomolov conjecture for abelian varieties, and give some partial answers to it. In fact, we insist in a main theorem that under some degeneracy condition, a closed subvariety of an abelian variety does not have a dense subset of small points if it is a non-special subvariety. The key of the proof is the study of the minimal dimension of the components of a canonical measure on the tropicalization of the closed subvariety. Then we can apply the tropical version of equidistribution theory due to Gubler. This article includes an appendix by Walter Gubler. He shows that the minimal dimension of the components of a canonical measure is equal to the dimension of the abelian part of the subvariety. We can apply this result to make a further contribution to the geometric Bogomolov conjecture.Comment: 30 page

MicroR159 regulation of most conserved targets in Arabidopsis has negligible phenotypic effects

BACKGROUND A current challenge of microRNA (miRNA) research is the identification of biologically relevant miRNA:target gene relationships. In plants, high miRNA:target gene complementarity has enabled accurate target predictions, and slicing of target mRNAs has facilitated target validation through rapid amplification of 5' cDNA ends (5'-RACE) analysis. Together, these approaches have identified more than 20 targets potentially regulated by the deeply conserved miR159 family in Arabidopsis, including eight MYB genes with highly conserved miR159 target sites. However, genetic analysis has revealed the functional specificity of the major family members, miR159a and miR159b is limited to only two targets, MYB33 and MYB65. Here, we examine the functional role of miR159 regulation for the other potential MYB target genes. RESULTS For these target genes, functional analysis failed to identify miR159 regulation that resulted in any major phenotypic impact, either at the morphological or molecular level. This appears to be mainly due to the quiescent nature of the remaining family member, MIR159c. Although its expression overlaps in a temporal and spatial cell-specific manner with a subset of these targets in anthers, the abundance of miR159c is extremely low and concomitantly a mir159c mutant displays no anther defects. Examination of potential miR159c targets with conserved miR159 binding sites found neither their spatial or temporal expression domains appeared miR159 regulated, despite the detection of miR159-guided cleavage products by 5'-RACE. Moreover, expression of a miR159-resistant target (mMYB101) resulted predominantly in plants that are indistinguishable from wild type. Plants that displayed altered morphological phenotypes were found to be ectopically expressing the mMYB101 transgene, and hence were misrepresentative of the in vivo functional role of miR159. CONCLUSIONS This study presents a novel explanation for a paradox common to plant and animal miRNA systems, where among many potential miRNA-target relationships usually only a few appear physiologically relevant. The identification of a quiescent miR159c:target gene regulatory module in anthers provides a likely rationale for the presence of conserved miR159 binding sites in many targets for which miR159 regulation has no obvious functional role. Remnants from the demise of such modules may lead to an overestimation of miRNA regulatory complexity when investigated using bioinformatic, 5'-RACE or transgenic approaches.RSA was funded by an ANU postgraduate scholarship and by a CSIRO Emerging Science Initiative. JL is the recipient of an ANU international student postgraduate scholarship. This research was supported by an Australian Research Council grant DP0773270

Thermoelectric cross-plane properties on p- and n-Ge/SixGe1-x superlattices

Silicon and germanium materials have demonstrated an increasing attraction for energy harvesting, due to their sustainability and integrability with complementary metal oxide semiconductor and micro-electro-mechanical-system technology. The thermoelectric efficiencies for these materials, however, are very poor at room temperature and so it is necessary to engineer them in order to compete with telluride based materials, which have demonstrated at room temperature the highest performances in literature [1]. Micro-fabricated devices consisting of mesa structures with integrated heaters, thermometers and Ohmic contacts were used to extract the cross-plane values of the Seebeck coefficient and the thermal conductivity from p- and n-Ge/SixGe1-x superlattices. A second device consisting in a modified circular transfer line method structure was used to extract the electrical conductivity of the materials. A range of p-Ge/Si0.5Ge0.5 superlattices with different doping levels was investigated in detail to determine the role of the doping density in dictating the thermoelectric properties. A second set of n-Ge/Si0.3Ge0.7 superlattices was fabricated to study the impact that quantum well thickness might have on the two thermoelectric figures of merit, and also to demonstrate a further reduction of the thermal conductivity by scattering phonons at different wavelengths. This technique has demonstrated to lower the thermal conductivity by a 25% by adding different barrier thicknesses per period

Disseminated Invasive Aspergillosis with Cerebral Involvement Successfully Treated with Caspofungin and Voriconazole

We describe a case of cerebral aspergillosis which was successfully treated with a combination of caspofungin and voriconazole. The patient remains in remission 18 months after stopping antifungal treatment. We discuss primary and salvage therapy of invasive aspergillosis with focus on cerebral involvement. Since historical data showed a fatal outcome in most cases, amphotericin B does not cross the blood brain barrier while voriconazole does, we chose a combination of voriconazole plus caspofungin as primary therap

Fuel-cell performance of multiply-crosslinked polymer electrolyte membranes prepared by two-step radiation technique

A multiply-crosslinked polymer electrolyte membrane was prepared by the radiation-induced co-grafting of styrene and a bis(vinyl phenyl)ethane (BVPE) crosslinker into a radiation-crosslinked polytetrafluoroethylene (cPTFE) film. We then investigated its H2/O2 fuel-cell performance at 60 and 80ºC in terms of the effect of radiation and chemical crosslinking. At 60ºC, all the membranes initially exhibited similar performance, but only the cPTFE-based membranes were durable at 80ºC, indicating the necessity of radiation crosslinking in the PTFE main chains. Importantly, cell performance of the multiply-crosslinked membrane was found high enough to reach that of a Nafion112 membrane. This is probably because the BVPE crosslinks in the graft component improved the membrane-electrode interface in addition to membrane durability. After severe OCV hold tests at 80 and 95ºC, the performance deteriorated, while no significant change was observed in ohmic resistivity. Accordingly, our membranes seemed so chemically stable that an influence on overall performance loss could be negligible

Electronic Event–based Surveillance for Monitoring Dengue, Latin America

Dengue, a potentially fatal disease, is spreading around the world. An estimated 2.5 billion people in tropical and subtropical regions are at risk. Early detection of outbreaks is crucial to prevention and control of dengue virus and other viruses. Case reporting may often take weeks or months. Therefore, researchers explored whether electronic sources of real-time information (such as Internet news outlets, health expert mailing lists, social media sites, and queries to online search engines) might be faster, and they were. Although information from unofficial sources should be interpreted with caution, when used in conjunction with traditional case reporting, real-time electronic surveillance can help public health authorities allocate resources in time to avert full-blown epidemics

Air suctioning during colon biopsy acquisition reduces bacterial contamination

Background and Aim: Contamination of endoscopy suites with bacteria during procedures is of concern particularly through droplets during handling of biopsy specimens. It has been advocated that suctioning while removing the biopsy forceps could help to reduce potentially hazardous bioaerosols. The aim of the present study was to evaluate the efficacy of air suctioning during removal of the biopsy forceps. Materials and Methods: Airborne bacteria were collected by an impactor air-sampler (MAS-100). Fifty liters of air were collected continuously for 30 seconds at a 30 cm distance from the colonoscope suction channel. Room air samples were taken in the endoscopy suite in the morning prior to the beginning of the endoscopy program, during colonoscopy with a sham biopsy in the descending colon with and without suctioning and at the end of the procedure day. Standard 90 mm Petri dishes containing a selective medium for gram-positive cocci (CNA blood agar) were used with the impaction sampler and colony forming units/m3 (cfu) were determined. Results: Measurements were performed at fifty consecutive colonoscopies. Prior to the beginning of the endoscopy program, the bioaerosol burden in the colonoscopy suite reached a mean of 4.2 cfu/m3. During colonoscopies performed without suctioning at biopsy the bioaerosol burden increased to 29.4 cfu/m3 whereas this burden increased only to 15.1 cfu/m3 when the suctioning was applied during removal of the biopsy forceps. The difference in bioaerosol burden between suctioning and no suctioning was highly significant (p < 0.0005). At the end of the procedure day the airborne bacteria count dropped to 15.6 cfu/m3. The analysis of the colonies on the CNA blood agar identified predominantly enterococci. Staphylococci spp. and other gram-positive bacteria were rarely isolated. Conclusion: The present study indicates that the bioaerosol burden during handling of biopsy specimens is not neglectable but can be reduced by the simple habit of applying suctioning during acquisition of biopsies. This practice might be an important infection-control measure during gastrointestinal endoscopies