Selective Employment Subsidies: Can Okun’s Law Be Repealed?

[Excerpt] Concern that structural factors impede efficient labor market performance is evidenced in both statistical analyses of economic potential and policy proposals for selective employment subsidies. Estimates of the level and expected growth of full-employment GNP have recently been revised downward, as has the 3.2 unemployment multiplier implicit in Okun\u27s Law (see U.S. Council of Economic Advisers and George Perry). These indications of structural changes in labor markets reinforce statistics showing excessively high unemployment rates for youths and blacks, and labor force participation rates that are increasing for women and decreasing for men. The simultaneous concern with high inflation and high measured unemployment, in the context of major changes in labor force composition and increased variance in sectoral unemployment rates (see Perry), has brought forth numerous and sizable selective employment subsidy policies (SESP) in both the United States and Western Europe. The SESP, changes in potential GNP, and Okun\u27s Law are not unrelated phenomena. This paper explores that relationship. Section I presents a brief taxonomy of the primary SESPs which are currently being discussed in Western industrialized countries. Section II provides the economic rationale underlying these measures. Section III explores the relationship of SESP to the prospective growth of aggregate output, in the context of Okun\u27s Law. Evidence on the existence and magnitude of changes in employment decisions in response to the New Jobs Tax Credit (NJTC) is presented in Section IV

Does the Targeted Jobs Tax Credit Create Jobs at Subsidized Firms?

This paper uses the results of a survey of more than 3,500 private employers to determine whether use of the Targeted Jobs Tax Credit (TJTC) alters the level of a firm\u27s employment and/or whom the firm hires. We estimate that each subsidized hire generates between .13 and .3 new jobs at a participating firm. Use of the program also appears to induce employers to hire more young workers (age 25 and under). Our results suggest, however, that at least 70 percent of the tax credits granted employers are payments for workers who would have been hired even without the subsidy. Such payments represent mere transfers to employers

Inter-frequency Bias Estimation for the GPS Monitor Station Network

The inter-frequency bias (IFB) is present in all dual frequency combinations of GPS pseudorange and carrier phase observables. It is caused by the path dependent signal delays in both the satellite and receiver. That delay can be directly measured for a space vehicle prior to launch, or for a ground based receiver prior to its being used in the field. However the bias is known to drift, and monitoring the delay estimate by direct measurement is time consuming for ground based receivers and impossible for deployed space vehicles. Hansen (2002) examined the observability of IFB through a global model of ionosphere total electron content (TEC). Variation in the receiver portion of the IFB can also be observed in receivers with antennae in a zero-baseline configuration. This is referred to as an inter-receiver bias (IRB). In this study a Kalman filter is formulated to observe IFBs and IRBs. Process noise is used to allow the filter to track changes in the IFBs and IRBs. The filter also implements constraints to reflect the fact that a given IRB is not linearly independent of the IFBs. Because the receivers are distributed on a global scale, the Kalman filter requires a globally observable phenomenon by which to tie the IFBs. In this case ionosphere delay provides such a phenomenon. The filter was applied to observations collected by GPS monitor stations that comprise the National Geospatial- Intelligence Agency Monitor Station Network (MSN). Each monitor station contains two geodetic quality receivers in a zero-baseline configuration and continuously collects GPS observations. The GPS observations collected by this network are used to produce both precise ephemeris and the broadcast ephemeris. GPS observations made through the network are incorporated into the GPS Master Control Station (MCS) Kalman filter of the Operational Control System (OCS) (Wiley, 2006). The Kalman filter in the OCS estimates the orbital parameters that are transmitted via the navigation message. If estimated effectively, knowledge of the receiver portion of the IFB can aid in achieving better ionosphere models. IFBs are made observable using a global ionosphere delay model. A ninth order spherical harmonic model derived by Y.C. Chao (1997) was used in this study for ionosphere delay. Chao used this spherical harmonic model to capture ionospheric variations that occurred over a smaller global region in his IFB estimation process. In this study a similar model was used but was verified using observations that span a global coverage. The receiver portion of the IFB is observed precisely using the IRB. In this study error terms were introduced into the Kalman filter design to realign the IRB estimates to the IFB estimates produced for each of the two receivers in a zero baseline configuration. For a nominal epoch of measurement, there were 198 noisy measurements used each epoch to generate twelve monitor station specific IRBs. The IRB estimates showed small, decimeter level dynamic variation over the period of a day. The quality of the IFB estimate directly affects the quality of the ionospheric model formed during the estimation process. Results verify that the filter is operating properly. The ionosphere model, though simple, demonstrates that the total electron content (TEC) peaks during local noon and is at a minimum during local night. IRB estimates are roughly constant over time and have a magnitude of less than 2.5 meters. Similar estimates are formed for the IFBs, however when processing one day of observations, the IFB estimates are less stable than those of the IRBs. Future effort will involve tuning the filter, and establishing criteria for its convergence

Resonances, Unstable Systems and Irreversibility: Matter Meets Mind

The fundamental time-reversal invariance of dynamical systems can be broken in various ways. One way is based on the presence of resonances and their interactions giving rise to unstable dynamical systems, leading to well-defined time arrows. Associated with these time arrows are semigroups bearing time orientations. Usually, when time symmetry is broken, two time-oriented semigroups result, one directed toward the future and one directed toward the past. If time-reversed states and evolutions are excluded due to resonances, then the status of these states and their associated backwards-in-time oriented semigroups is open to question. One possible role for these latter states and semigroups is as an abstract representation of mental systems as opposed to material systems. The beginnings of this interpretation will be sketched.Comment: 9 pages. Presented at the CFIF Workshop on TimeAsymmetric Quantum Theory: The Theory of Resonances, 23-26 July 2003, Instituto Superior Tecnico, Lisbon, Portugal; and at the Quantum Structures Association Meeting, 7-22 July 2004, University of Denver. Accepted for publication in the Internation Journal of Theoretical Physic

B658: Susceptibility and Vulnerability of Forests to the Pine Leaf Aphid Pineus Pinilolile (Fitch) (Adelgidae)

In the late 1950s, early 1960s, Maine and surrounding regions experienced an outbreak of the pine leaf aphid (or adelgid). The population progression began about 1955, as indicated by tree growth reductions (2), a peak was reached about 1961, after which populations gradually regressed through the late 1960s. As a result of the outbreak, there was considerable growth reduction of white pine in some regions and scattered tree mortality. Among the many observations on the insect made during the outbreak were (a) the aphid was abundant in only certain portions of Maine and remained uncommon in the remainder of the state, and (b) in those regions where the insect was abundant, some stands of pine suffered relatively severe damage while others were largely unaffected. This study sought to provide explanations for differences in the abundance of aphids throughout the state and the varying amount of damage between stands. Information gained in a study of this sort is useful in explaining the distribution and abundance of the insect and in suggesting silvicultural procedures designed to increase resistance of stands to insect damage.https://digitalcommons.library.umaine.edu/aes_bulletin/1015/thumbnail.jp

Reducing Orbit Covariance for Continuous Thrust Spacecraft Transfers

The calculus of variations is used to develop the necessary theory and derive the optimality conditions for a spacecraft to transfer between a set of initial and final conditions, while minimizing a combination of fuel consumption and a function of the estimation error covariance matrix associated with the spacecraft state. The theory is developed in a general manner that allows for multiple observers, moving observers, covariance associated with an arbitrary frame, a wide variety of observation types, multiple gravity bodies, and uncertainties in the spacecraft equations of motion based on the thrusting status of the engine. A series of example trajectories from low Earth orbit (LEO) to a near geosynchronous Earth orbit (GEO) shows that either the trace of the covariance at the final time or the integral of the trace of the covariance matrix associated with the error in the Cartesian position and velocity can be reduced significantly with a small increase in the fuel consumption. An additional example illustrates the covariance associated with the semimajor axis can be significantly reduced for a transfer from Earth orbit to lunar orbit. This example illustrates multiple, moving observers as well as a transfer in a multi-body gravitational field

Homologous Recombination and Its Role in Carcinogenesis

Cancer develops when cells no longer follow their normal pattern of controlled growth. In the absence or disregard of such regulation, resulting from changes in their genetic makeup, these errant cells acquire a growth advantage, expanding into precancerous clones. Over the last decade, many studies have revealed the relevance of genomic mutation in this process, be it by misreplication, environmental damage, or a deficiency in repairing endogenous and exogenous damage. Here, we discuss homologous recombination as another mechanism that can result in a loss of heterozygosity or genetic rearrangements. Some of these genetic alterations may play a primary role in carcinogenesis, but they are more likely to be involved in secondary and subsequent steps of carcinogenesis by which recessive oncogenic mutations are revealed. Patients, whose cells display an increased frequency of recombination, also have an elevated frequency of cancer, further supporting the link between recombination and carcinogenesis

Analysis and Design of a Sub-Optimal MEKF for Low Earth Orbit Attitude Estimation Using a Radically Inexpensive MEMS IMU

A previous study investigated the feasibility in using a radically inexpensive MEMS IMU with a GPS and a model of Earth’s magnetic field for attitude determination. A Multiplicative Extended Kalman Filter was designed to estimate the biases and errors associated with the IMU and reduce attitude uncertainty. States with large influence on overall uncertainty were identified through error budget and sensitivity analysis. It was determined that the complexity of the Kalman filter could be significantly reduced by removing 18 of the 42-element state vector. In this study, the sub- optimal filter is designed and its feasibility for attitude determination is demonstrated through Monte Carlo simulations. The primary mission is inertial attitude control in support of spacecraft mission operations in low Earth orbit. Our challenge is to create a radically inexpensive spacecraft using commercially available and bespoke subsystems. This inhibits the use of expensive and larger attitude sensors such as star cameras and sun sensors. While the proposed system uses a Raspberry Pi as the main flight computer, reducing computational complexity enhances the ability to provide near-real-time attitude solutions. This sub-optimal MEKF therefore improves mission capabilities by reducing computational load

Shifting the Intertial Navigation Paradigm with the MEMS Technology

"Why don't you use MEMS?" is of the most common questions posed to navigation systems engineers designing inertial navigation solutions in the modern era. The question stems from a general understanding that great strides have been made in terrestrial MEMS accelerometers and attitude rate sensors in terms of accuracy, mass, and power. Yet, when compared on a unit-to-unit basis, MEMS devices do not provide comparable performance (accuracy) to navigation grade sensors in several key metrics. This paper will propose a paradigm shift where the comparison in performance is between multiple MEMS devices and a single navigation grade sensor. The concept is that systematically, a sufficient number of MEMS sensors may mathematically provide comparable performance to a single navigation grade device and be competitive in terms power and mass allocations when viewed on a systems level. The implication is that both inertial navigation system design and fault detection, identification, and recovery could benefit from a system of MEMS devices in the same way that swarm sensing has benefited Earth observation and astronomy. A survey of the state of the art in inertial sensor accuracy scaled by mass and power will be provided to show the scaled error in MEMS and navigation graded devices, a mathematical comparison of multi-unit to single-unit sensor errors will be developed, and preliminary application to an Orion lunar skip atmospheric entry trajectory will be explored