2,537 research outputs found
Water Resources International Development: What On Earth Are We Doing?
Large agencies such as the World Bank, the Millennium Challenge Corporation, the United Nations, regional development banks (such as the Asian Development Bank), and philanthropic organizations (such as the Rockefeller Foundation) are actively engaged in water resources development in low-income countries. Why? And what metrics do they use to decide if the investments of hundreds of millions or billions of dollars in water infrastructure projects are justified? And what accommodations do they tend to make for risks such as climate change? And what attention do they tend to give to questions of equity? I probably have no idea. But I’ve worked with many of these agencies for a decade or so, and I’ll give you what I know, and raise questions for discussion. I’ll plan to use two examples, primarily: Mexico City rural-urban water transfers, and hydropower development in Nepal
Spatially Resolved Observations of the Bipolar Optical Outflow from the Brown Dwarf 2MASSJ12073347-3932540
Studies of brown dwarf (BD) outflows provide information pertinent to
questions on BD formation, as well as allowing outflow mechanisms to be
investigated at the lowest masses. Here new observations of the bipolar outflow
from the 24 M BD, 2MASSJ12073347-3932540 are presented. The outflow was
originally identified through the spectro-astrometric analysis of the
[OI]6300 emission line. Follow-up observations consisting of spectra
and [SII], R-band and I-band images were obtained. The new spectra confirm the
original results and are used to constrain the outflow PA at
65. The [OI]6300 emission line region is spatially resolved
and the outflow is detected in the [SII] images. The detection is firstly in
the form of an elongation of the point spread function along the direction of
the outflow PA. Four faint knot-like features (labelled {\it A-D}) are also
observed to the south-west of 2MASSJ12073347-3932540 along the same PA
suggested by the spectra and the elongation in the PSF. Interestingly, {\it D},
the feature furthest from the source is bow-shaped with the apex pointing away
from 2MASSJ12073347-3932540. A color-color analysis allows us to conclude that
at least feature {\it D} is part of the outflow under investigation while {\it
A} is likely a star or galaxy. Follow-up observations are needed to confirm the
origin of {\it B} and {\it C}. This is a first for a BD, as BD optical outflows
have to date only been detected using spectro-astrometry. This result also
demonstrates for the first time that BD outflows can be collimated and
episodic.Comment: Accepted by ApJ, ref ApJ89096R
Motorcycle Eyes
As technology continues to advance the safety factor has increased for vehicles on the roads. However, not much has been done to help improve the safety of motorcyclist. To help to solve this problem a wireless blind spot indicator for a motorcycle helmet will be designed. It will be powered off the motorcycle and have indication zones for the left, right, and rear blind spots. The system will alert the rider if a vehicle is within 7 meters of the back of the motorcycle in any of the mentioned blind spots. The radar sensors will detect the vehicle and send a signal to a microcontroller on the motorcycle which will wirelessly communicate to another microcontroller in the helmet via Bluetooth. The microcontroller in the helmet will then indicate to the rider which blind spot in occupied. This technology is already being utilized on cars and now it can hopefully be used to help insure the safety of motorcyclist as well
Deep H-band Galaxy Counts and Half-light Radii from HST/NICMOS Parallel Observations
We present deep galaxy counts and half-light radii from F160W
() images obtained with NICMOS on HST. Nearly 9 arcmin
have been imaged with camera 3, with depths ranging from H = 24.3 to
25.5 in a 0.6 diameter aperture. The slope of the counts fainter than H~ is 0.31, and the integrated surface density to H is galaxies per square degree. The half-light radii of the galaxies declines
steeply with apparent magnitude. At H~ we are limited by both the
delivered FWHM and the detection threshold of the images.Comment: 8 pages. Accepted for publication in ApJ Letter
Land Collateral and Labor Market Dynamics in France
The value of land in the balance sheet of French firms correlates positively with their hiring and investment flows. To explore the relationship between these variables, we develop a macroeconomic model with firms that are subject to both credit and labor market frictions. The value of collateral is driven by the forward-looking dynamics of the land price, which reacts endogenously to fundamental and non-fundamental (sunspot) shocks. We calibrate the model to French data and find that land price shocks give rise to significant amplification and hump-shaped responses of investment, vacancies and unemployment that are in line with the data. We show that both the endogenous movements in the firm’s discount factor and the sluggish response of the land price are key elements that drive the results
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