Sticky information and sticky prices

In the U.S. and Europe, prices change somewhere between every six months and once a year. Yet nominal macro shocks seem to have real effects lasting well beyond a year. "Sticky information" models, as posited by Sims (2003), Woodford (2003), and Mankiw and Reis (2002), can reconcile micro flexibility with macro rigidity. We simulate a sticky information model in which price setters do not update their information on macro shocks as often as they update their information on micro shocks. Compared to a standard menu cost model, price changes in this model reflect older macro shocks. We then examine price changes in the micro data underlying the U.S. CPI. These price changes do not reflect older information, thereby exhibiting a similar response to that of the standard menu cost model. However, the empirical test hinges on staggered information updating across firms; it cannot distinguish between a full information model and a model where firms have equally old information.Prices

Real rigidities and nominal price changes

A large literature seeks to provide microfoundations of price setting for macro models. A challenge has been to develop a model in which monetary policy shocks have the highly persistent effects on real variables estimated by many studies. Nominal price stickiness has proved helpful but not sufficient without some form of "real rigidity" or "strategic complementarity." We embed a model with a real rigidity a la Kimball (1995), wherein consumers flee from relatively expensive products but do not flock to inexpensive ones. We estimate key model parameters using micro data from the U.S. CPI, which exhibit sizable movements in relative prices of substitute products. When we impose a significant degree of real rigidity, fitting the micro price facts requires very large idiosyncratic shocks and implies large movements in micro quantities.Prices ; Pricing

Migration to next generation access networks: a real option approach

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Properties of Hot Stars in the Wolf-Rayet galaxy NGC5253 from ISO Spectroscopy

ISO-SWS spectroscopy of the WR galaxy NGC5253 is presented, and analysed to provide estimates of its hot young star population. Our approach differs from previous investigations in that we are able to distinguish between the regions in which different infrared fine-structure lines form, using complementary ground-based observations. The high excitation nebular [SIV] emission is formed in a very compact region, which we attribute to the central super-star-nucleus, and lower excitation [NeII] nebular emission originates in the galactic core. We use photo-ionization modelling coupled with the latest theoretical O-star flux distributions to derive effective stellar temperatures and ionization parameters of Teff>38kK, logQ=8.25 for the compact nucleus, with Teff=35kK, logQ<8 for the larger core. Results are supported by more sophisticated calculations using evolutionary synthesis models. We assess the contribution that Wolf-Rayet stars may make to highly ionized nebular lines (e.g. [OIV]). From our Br(alpha) flux, the 2" nucleus contains the equivalent of approximately 1000 O7V star equivalents and the starburst there is 2-3Myr old; the 20" core contains about 2500 O7V star equivalents, with a representative age of 5Myr. The Lyman ionizing flux of the nucleus is equivalent to the 30 Doradus region. These quantities are in good agreement with the observed mid-IR dust luminosity of 7.8x10^8 L(sun) Since this structure of hot clusters embedded in cooler emission may be common in dwarf starbursts, observing a galaxy solely with a large aperture may result in confusion. Neglecting the spatial distribution of nebular emission in NGC5253, implies `global' stellar temperatures (or ages) of 36kK (4.8Myr) and 39kK (2.9 or 4.4Myr) from the observed [NeIII/II] and [SIV/III] line ratios, assuming logQ=8.Comment: 16 pages, 7 figures, uses mn.sty, to appear in MNRA

WP 2015-331

Population aging and attendant pressures on public budgets have spurred considerable interest in understanding factors that influence retirement timing. A range of sociodemographic and economic characteristics have been shown to predict both earlier and later retirement. Less is known about the role of occupations and their characteristics on the work choices of older workers. Knowing more about the occupations that workers seem to stay in longer or leave earlier may point the way to policy interventions that are beneficial to both individuals and system finances. This project uses detailed occupational categories and work characteristics in the Health and Retirement Study (HRS) linked to information in the Occupational Information Network (O*NET) to examine compositional changes in occupations held by older workers over time; to provide some basic and interesting information about relationships between occupations and their characteristics and retirement expectations and outcomes; and to shed some light on which occupations and associated characteristics might encourage or discourage longer working lives. There are large percentage changes (increases in decreases) in the percentage of older workers in occupations over time. Considering detailed as opposed to aggregated occupational categories yields interesting additional information. Jobs that HRS respondents say entail less physical effort, less stress, and jobs that have not increased in difficulty in recent decades, and those in which people can reduce hours if desired, are associated with longer work. While the traditional blue collar-retire earlier and white collar-work longer associations emerge, we find interesting exceptions that suggest fruitful directions for future research.Social Security Administration5 RRC08098401-07http://deepblue.lib.umich.edu/bitstream/2027.42/117396/1/wp331.pd

Slopes To Prevent Trapping of Bubbles in Microfluidic Channels

The idea of designing a microfluidic channel to slope upward along the direction of flow of the liquid in the channel has been conceived to help prevent trapping of gas bubbles in the channel. In the original application that gave rise to this idea, the microfluidic channels are parts of micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. It is necessary to prevent trapping of gas bubbles in these devices because uninterrupted liquid pathways are essential for sustaining the electrical conduction and flows that are essential for CE. The idea is also applicable to microfluidic devices that may be developed for similar terrestrial microCE biotechnological applications or other terrestrial applications in which trapping of bubbles in microfluidic channels cannot be tolerated. A typical microCE device in the original application includes, among other things, multiple layers of borosilicate float glass wafers. Microfluidic channels are formed in the wafers, typically by use of wet chemical etching. The figure presents a simplified cross section of part of such a device in which the CE channel is formed in the lowermost wafer (denoted the channel wafer) and, according to the present innovation, slopes upward into a via hole in another wafer (denoted the manifold wafer) lying immediately above the channel wafer. Another feature of the present innovation is that the via hole in the manifold wafer is made to taper to a wider opening at the top to further reduce the tendency to trap bubbles. At the time of reporting the information for this article, an effort to identify an optimum technique for forming the slope and the taper was in progress. Of the techniques considered thus far, the one considered to be most promising is precision milling by use of femtosecond laser pulses. Other similar techniques that may work equally well are precision milling using a focused ion beam, or a small diamond-tipped drill bit

Can Regenerative Agriculture increase national soil carbon stocks? : Simulated country scale adoption of reduced tillage, cover cropping, and ley-arable integration using RothC

ACKNOWLEDGMENTS We would like to thank Dr Andrew C. Martin for advice on our modelling framework. The authors would like to acknowledge the use of the University of Oxford Advanced Research Computing facility in carrying out this work. This work was supported by funding from the Biotechnology and Biological Sciences Research Council (BBSRC) [grant number BB/M011224/1]. PCB would like to acknowledge funding by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy [EXC 2075 – 390740016]. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Peer reviewedPostprin

Modeling and generating moving trees from video

We present a probabilistic approach for the automatic production of tree models with convincing 3D appearance and motion. The only input is a video of a moving tree that provides us an initial dynamic tree model, which is used to generate new individual trees of the same type. Our approach combines global and local constraints to construct a dynamic 3D tree model from a 2D skeleton. Our modeling takes into account factors such as the shape of branches, the overall shape of the tree, and physically plausible motion. Furthermore, we provide a generative model that creates multiple trees in 3D, given a single example model. This means that users no longer have to make each tree individually, or specify rules to make new trees. Results with different species are presented and compared to both reference input data and state of the art alternatives

Work restructuring and changing craft identity: the Tale of the Disaffected Weavers (or what happens when the rug is pulled from under your feet)

This article explores the changes in worker identity that can occur during manufacturing restructuring – specifically those linked to the declining status of craft work – through an in-depth case study of Weaveco, a UK carpet manufacturer. An analysis of changes in the labour process is followed by employee reactions centred on the demise of the traditional craft identity of male carpet weavers. The voices of the weavers dramatize the tensions involved in reconstructing their masculine identity, and we consider the implications this has for understanding gendered work relations