"Hard Times, Easy Money? Countercyclical Stabilization in an Uncertain Economy"

The tools of countercyclical monetary policy have been brought fully to bear on a potentially severe recession. This note argues, however, that such a policy is less effective in times such as these--that is, when uncertainty is especially high--and so is likely to be particularly ineffective in combating the current economic slowdown.

Selecting films for sex research: Gender differences in erotic film preference

The official published version can be obtained from the link below.The aim of this study was to explore gender differences in sexual responsiveness to erotic films that had been selected for their differential appeal for men and women. A secondary objective was to identify variables that influence sexual arousal and explore whether these variables differ for men and women. Fifteen men (M age = 26 yrs) and 17 women (M age = 24 yrs) were presented with 20 film clips depicting heterosexual interactions, half of which were female- and the other half male-selected, and were asked to rate the clips on a number of dimensions. Overall, men found the film clips more sexually arousing than did the women. Gender differences in arousal were negligible for female-selected clips but substantial for male-selected clips. Furthermore, men and women experienced higher levels of sexual arousal to clips selected for individuals of their own gender. Cluster regression analyses, explaining 77% of the variance for male and 65% for female participants, revealed that men's sexual arousal was dependent upon the attractiveness of the female actor, feeling interested, and both imagining oneself as a participant and watching as an observer. For women, with all variables entered, only imagining oneself as a participant contributed to sexual arousal ratings. The findings suggest that how films are selected in sex research is an important variable in predicting levels of sexual arousal reported by men and women

Spitzer spectroscopy of circumstellar disks in the 5 Myr old upper Scorpius OB association

We present mid-infrared spectra between 5.2 and 38 μm for 26 disk-bearing members of the ~5 Myr old Upper Scorpius OB association obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. We find clear evidence for changes in the spectral characteristics of dust emission between the early-type (B+A) and late-type (K+M) infrared excess stars. The early-type members exhibit featureless continuum excesses that become apparent redward of ~8 μm. In contrast, 10 and 20 μm silicate features or polycyclic aromatic hydrocarbon emission are present in all but one of the late-type excess members of Upper Scorpius. The strength of silicate emission among late-type Upper Scorpius members is spectral-type dependent, with the most prominent features being associated with K5-M2-type stars. By fitting the spectral energy distributions (SED) of a representative sample of low-mass stars with accretion disk models, we find that the SEDs are consistent with models having inner disk radii ranging from ~0.2 to 1.2 AU. Complementary high-resolution (R ~ 33,000) optical (λλ4800-9200) spectra for the Upper Scorpius excess stars were examined for signatures of gaseous accretion. Of the 35 infrared excess stars identified in Upper Scorpius, only seven (all late-type) exhibit definitive signatures of accretion. Mass-accretion rates (M) for these stars were estimated to range from 10^–11 to 10^–8.9 M⊙ yr^–1. Compared to Class II sources in Taurus-Auriga, the disk population in Upper Scorpius exhibits reduced levels of near- and mid-infrared excess emission and an order of magnitude lower mass-accretion rates. These results suggest that the disk structure has changed significantly over the 2-4 Myr in age separating these two stellar populations. The ubiquity of depleted inner disks in the Upper Scorpius excess sample implies that such disks are a common evolutionary pathway that persists for some time

Italian Corporate Governance, Investment, and Finance

Italian industrial structure and financial markets have several distinct features. Italian firms are relatively small, few trade publicly and no corporate bond market exists. The limited types of external funds available to Italian firms makes them prone to financing constraints. We examine a panel containing over 1100 Italian firms. We find that firm size does not appear correlated with the severity of financing constraints. We also find that small firms are frequently mature. Our results suggest that young firms face financing constraints, while mature firms may develop relationships with lenders that lower the costs of external funds. Small, young firms appear to face the tightest financing constraints. Many firms are affiliated with pyramidal business groups. We find that affiliation with pyramidal business groups appears to reduce the effect of financing constraints. Our results have important implications for government policy to promote small firm growth in Italy.

Controlling Network Latency in Mixed Hadoop Clusters: Do We Need Active Queue Management?

With the advent of big data, data center applications are processing vast amounts of unstructured and semi-structured data, in parallel on large clusters, across hundreds to thousands of nodes. The highest performance for these batch big data workloads is achieved using expensive network equipment with large buffers, which accommodate bursts in network traffic and allocate bandwidth fairly even when the network is congested. Throughput-sensitive big data applications are, however, often executed in the same data center as latency-sensitive workloads. For both workloads to be supported well, the network must provide both maximum throughput and low latency. Progress has been made in this direction, as modern network switches support Active Queue Management (AQM) and Explicit Congestion Notifications (ECN), both mechanisms to control the level of queue occupancy, reducing the total network latency. This paper is the first study of the effect of Active Queue Management on both throughput and latency, in the context of Hadoop and the MapReduce programming model. We give a quantitative comparison of four different approaches for controlling buffer occupancy and latency: RED and CoDel, both standalone and also combined with ECN and DCTCP network protocol, and identify the AQM configurations that maintain Hadoop execution time gains from larger buffers within 5%, while reducing network packet latency caused by bufferbloat by up to 85%. Finally, we provide recommendations to administrators of Hadoop clusters as to how to improve latency without degrading the throughput of batch big data workloads.The research leading to these results has received funding from the European Unions Seventh Framework Programme (FP7/2007–2013) under grant agreement number 610456 (Euroserver). The research was also supported by the Ministry of Economy and Competitiveness of Spain under the contracts TIN2012-34557 and TIN2015-65316-P, Generalitat de Catalunya (contracts 2014-SGR-1051 and 2014-SGR-1272), HiPEAC-3 Network of Excellence (ICT- 287759), and the Severo Ochoa Program (SEV-2011-00067) of the Spanish Government.Peer ReviewedPostprint (author's final draft

Investment behavior, observable expectations, and internal funds: a comment on Cummins et al. (AER, 2006)

Cummins et al. (2006) construct a new measure of fundamentals, and show that the positive cash flow effects typically found in investment-Q models disappear when traditional Q is replaced with their new measure. Their results are not robust to small changes in their specification or in the dataset used to estimate their model. The explanatory power of cash flow does not disappear when replacing traditional Q with their new measure of Q; it is never there to begin with. Investment’s lack of sensitivity to cash flow may be because their data is biased towards firms with positive cash flow (it is negative for only 242 observations of 11431). This bias and our results mute their argument that the positive cash-flow effects obtained in such models may reflect a failure to control properly for fundamentals rather than the presence of financial constraints.Investment, Cash flow, Financial constraints.

Interconnect Energy Savings and Lower Latency Networks in Hadoop Clusters: The Missing Link

An important challenge of modern data centres running Hadoop workloads is to minimise energy consumption, a significant proportion of which is due to the network. Significant network savings are already possible using Energy Efficient Ethernet, supported by a large number of NICs and switches, but recent work has demonstrated that the packet coalescing settings must be carefully configured to avoid a substantial loss in performance. Meanwhile, Hadoop is evolving from its original batch concept to become a more iterative type of framework. Other recent work attempts to reduce Hadoop's network latency using Explicit Congestion Notifications. Linking these studies reveals that, surprisingly, even when packet coalescing does not hurt performance, it can degrade network latency much more than previously thought. This paper is the first to analyze the impact of packet coalescing in the context of network latency. We investigate how to design and configure interconnects to provide the maximum energy savings without degrading cluster throughput performance or network latency.The research leading to these results has received funding from the European Unions Seventh Framework Programme (FP7/2007–2013) under grant agreement number 610456 (Euroserver). The research was also supported by the Ministry of Economy and Competitiveness of Spain under the contracts TIN2012-34557 and TIN2015-65316-P, Generalitat de Catalunya (contracts 2014-SGR-1051 and 2014-SGR-1272), HiPEAC-3 Network of Excellence (ICT- 287759), and the Severo Ochoa Program (SEV-2011-00067) of the Spanish Government.Peer ReviewedPostprint (author's final draft

Investment in Infectious Disease Control Capacity: The Case of a Potential Foot-and-Mouth Disease Outbreak in California

Health Economics and Policy,

Ejection Forces and Friction Coefficients from Injection Molding Experiments Using Rapid Tooling Inserts

Experiments have been performed with injection mold inserts made using solid freeform fabrication processes in an effort to further study such applications for economic production of small quantities of parts. Static friction coefficients were determined for HDPE and HIPS against P-20 steel, sintered LaserForm ST-100, and stereolithography SL 5170 using the ASTM D 1894 standard. Injection mold inserts were constructed of the same three materials and were used to inject cylindrical parts using HDPE and HIPS. Ejection forces were measured, and a model was used to calculate ejection forces and apparent coefficients of static friction. Statistical analyses were used to determine the effects of packing time, cooling time and packing pressure on ejection force for the three insert types. This paper compares experimental and calculated ejection forces, compares standard friction test results to calculated apparent coefficients of friction, summarizes the statistical results, and comments on the feasibility of using rapid tooled inserts for injection molding.Mechanical Engineerin