Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches

The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize likely low-z interlopers in an optical/NIR search for high-z galaxies. We analyze the FIR SEDs of two galaxies that are proposed to be very high-redshift (z > 7) dropout candidates based on deep Hawk-I/VLT observations. The FIR SEDs are sampled with PACS/Herschel at 100 and 160 μm, with SPIRE/Herschel at 250, 350 and 500 μm and with LABOCA/APEX at 870 μm. We find that redshifts > 7 would imply extreme FIR SEDs (with dust temperatures >100 K and FIR luminosities >10^(13) L_⊙). At z ~ 2, instead, the SEDs of both sources would be compatible with those of typical ultra luminous infrared galaxies or submillimeter galaxies. Considering all available data for these sources from visible to FIR we re-estimate the redshifts and find z ~ 1.6–2.5. Owing to the strong spectral breaks observed in these galaxies, standard templates from the literature fail to reproduce the visible-to-near-IR part of the SEDs even when additional extinction is included. These sources strongly resemble dust-obscured galaxies selected in Spitzer observations with extreme visible-to-FIR colors, and the galaxy GN10 at z = 4. Galaxies with similar SEDs could contaminate other high-redshift surveys

Nanomechanical detection of the spin Hall effect

The spin Hall effect creates a spin current in response to a charge current in a material that has strong spin-orbit coupling. The size of the spin Hall effect in many materials is disputed, requiring independent measurements of the effect. We develop a novel mechanical method to measure the size of the spin Hall effect, relying on the equivalence between spin and angular momentum. The spin current carries angular momentum, so the flow of angular momentum will result in a mechanical torque on the material. We determine the size and geometry of this torque and demonstrate that it can be measured using a nanomechanical device. Our results show that measurement of the spin Hall effect in this manner is possible and also opens possibilities for actuating nanomechanical systems with spin currents.Comment: 5 pages + 2 pages supplementary material, 4 figures tota

Tax Policy in a Model of Search with Training

This paper develops a model of search on the labour market with training. The model reveals how the tax system can restore the social optimum if the Hosio s condition is not satisfied in the private equilibrium. Furthermore, the effects are explored of a second-best reform from average to marginal taxes when a given amount of public revenue has to be raised. We find that (i) a marginal wage tax is less distortionary to raise revenue than is an average tax per job, provided that training is not distorted initially; (ii) this conclusion may reverse in the presence of training distortions; (iii) marginal wage taxes are less distortionary in economies characterized by commitment in wage bargaining, such as the European labour market. Hence, tax reforms that reduce the average tax per job and raise the marginal wage tax, such as an EITC or a negative income tax, are more attractive in Europe than in the US.

Experiments on Unemployment Benefit Sanctions and Job Search Behavior

experiments;unemployment benefits;sanctions;job search

ABC\u27s of Behavioral Objectives--Putting Them to Work for Evaluation

With shrinking budgets, evaluation and accountability become increasing important in the justification and impact of Extension programs and faculty. The key to solving the accountability issue is to develop clear, concise behavioral objectives as a part of each educational activity. This article discusses how to write measurable behavioral objectives that should be used for both planning and evaluation of Extension programs. Examples of well written behavioral objectives that can be used to measure impact are included

Development of an Instrument to Identify Unique Supply Officer Knowledge

Air Force supply officers possess a unique body of knowledge. This unique body of supply officer knowledge is an Air Force intellectual asset. The value of these intellectual assets depends on the value created by the application of the organization\u27s knowledge and the value his knowledge creates. This thesis establishes a process for measuring the value created by unique supply officer knowledge. The first step in the methodology is to identify mandatory supply knowledge. This was accomplished through review of Air Force guidance and se of a knowledge audit questionnaire. The knowledge audit provides a means for assessing what knowledge is needed or contained within an organization. The knowledge audit conducted as part of this research effort resulted in the development of 11 mandatory supply knowledge categories consisting of 49 sub-categories. The second phase of the methodology requires the identification of unique supply officer knowledge. The identification of unique supply officer knowledge is necessary so that the contributions, or value, of the knowledge to the accomplishment of the Air Force mission can be determined. This research concludes with the development and testing of a survey instrument for use in identifying unique supply officer knowledge