The Detectability of Transit Depth Variations due to Exoplanetary Oblateness and Spin Precession

Knowledge of an exoplanet's oblateness and obliquity would give clues about its formation and internal structure. In principle, a light curve of a transiting planet bears information about the planet's shape, but previous work has shown that the oblateness-induced signal will be extremely difficult to detect. Here we investigate the potentially larger signals due to planetary spin precession. The most readily detectable effects are transit depth variations (T$\delta$V) in a sequence of light curves. For a planet as oblate as Jupiter or Saturn, the transit depth will undergo fractional variations of order 1%. The most promising systems are those with orbital periods of approximately 15--30 days, which is short enough for the precession period to be less than about 40 years, and long enough to avoid spin-down due to tidal friction. The detectability of the T$\delta$V signal would be enhanced by moons (which would decrease the precession period) or planetary rings (which would increase the amplitude). The Kepler mission should find several planets for which precession-induced T$\delta$V signals will be detectable. Due to modeling degeneracies, Kepler photometry would yield only a lower bound on oblateness. The degeneracy could be lifted by observing the oblateness-induced asymmetry in at least one transit light curve, or by making assumptions about the planetary interior.Comment: Accepted for publication in The Astrophysical Journa

Axial performance of self-consolidating concrete-filled fiber tubes

Concrete filled fiber tubes can be used to increase ductility and strength of a concrete member and self-consolidating concrete is an ideal material to use in practical applications of concrete-filled fiber tubular columns. However, the propensity of self-consolidating concrete to autogenous shrinkage could reduce the effectiveness of the concrete confinement. This research investigates the use of self-consolidating concrete in pre-cast FRP tubes and various methods of shrinkage reduction and compensation to increase the axial performance of said self-consolidating concrete-filled fiber tubes. Axial compression tests were performed under monotonic and cyclic conditions to determine the stress-strain relationship of the self-consolidating concrete filled fiber tubes. The test results obtained from the compression tests are presented and examined”--Abstract, page iv

Analytic Approximations for Transit Light Curve Observables, Uncertainties, and Covariances

The light curve of an exoplanetary transit can be used to estimate the planetary radius and other parameters of interest. Because accurate parameter estimation is a non-analytic and computationally intensive problem, it is often useful to have analytic approximations for the parameters as well as their uncertainties and covariances. Here we give such formulas, for the case of an exoplanet transiting a star with a uniform brightness distribution. We also assess the advantages of some relatively uncorrelated parameter sets for fitting actual data. When limb darkening is significant, our parameter sets are still useful, although our analytic formulas underpredict the covariances and uncertainties.Comment: 33 pages, 14 figure

Parameter Estimation from Time-Series Data with Correlated Errors: A Wavelet-Based Method and its Application to Transit Light Curves

We consider the problem of fitting a parametric model to time-series data that are afflicted by correlated noise. The noise is represented by a sum of two stationary Gaussian processes: one that is uncorrelated in time, and another that has a power spectral density varying as $1/f^\gamma$. We present an accurate and fast [O(N)] algorithm for parameter estimation based on computing the likelihood in a wavelet basis. The method is illustrated and tested using simulated time-series photometry of exoplanetary transits, with particular attention to estimating the midtransit time. We compare our method to two other methods that have been used in the literature, the time-averaging method and the residual-permutation method. For noise processes that obey our assumptions, the algorithm presented here gives more accurate results for midtransit times and truer estimates of their uncertainties.Comment: Accepted in ApJ. Illustrative code may be found at http://www.mit.edu/~carterja/code/ . 17 page

Comparing Dominant and Non-Dominant Torque and Work Using Biodex 3 Isokinetic Protocol for Knee Flexors and Extensors

INTRODUCTION. There is often a misconception when looking at comparing dominant and non-dominant limbs of any sort. Although there will be a lack of control in non-dominant limbs compared to dominant, the amount of torque and power associated with each limb may be equal; even so, there may be an instance of bilateral deficit, where even though the dominant limb may be used to do work on a specific limb, the non-dominant limb may still receive strength benefits. PURPOSE. The main purpose of this study is to directly relate ability (torque and total work) in both dominant and non-dominate limbs with a focus on knee flexion and extension. METHODS. Participants: Four (N = 4; 4 males, 0 females) volunteers were utilized for this study. The average age of the participants were 24.5 + 1.73 years old, average height was 71.75 + 3.20” (inches or 182.245 centimeters), and average weight was 183.26 + 45.78 pounds (83.3 kilograms). Methodology: Upon arriving to the lab, each participant was measured for height (recorded in inches) and weight (recorded in kilograms), as well as age was recorded (years). Each participant was added into the system when they attempted to perform the protocol. The protocol utilized isokinetic concentric/concentric contractions on the knee for three separate speeds or sets (30/s, 60/s, and 90/s); each set included 5 repetitions. Upon completion of each set (5 repetitions) the participant would be allowed 10 seconds of rest. Following the same protocol, all participants would complete the test using their non-dominate leg. RESULTS. The value and percent difference associated with dominant and non-dominant extension (both torque and work) were rather large. As seen in the percent difference section, the value of each percent difference were at least 7.83% (min) and as high as 27.43% (max). There was also a noticeable percent difference associated with 90/s in flexion for both torque and work between dominant and non-dominant with values at torque = 19.97% and work = 16.23%. DISCUSSION. This study may help provide insight into how dominant and non-dominant limbs may be trained and how they may be equal even without training. This may be untrue due to many variables, but this study has allowed a certain insight into how dominant and non-dominant limbs may be equal in gross motor movements. Results that find non-dominant to dominant differences may be errors due the tester and/or the participant; it may be due to the participant because of situational awareness, they may learn the protocol and movements with one leg and adjust using the other

Congregational Social Work: An Experiential Sharing

Congregational social work is professional social work practice that takes place in the setting of a congregation. This term was first coined and used by Garland and Yancey in the year 2012. "Congregational Social Work" is defined as those social work services that are offered in and through a religious congregation, whether the employer is the congregation itself or a social service or denominational agency working in collaboration with congregations. In this paper "Congregational Social Work" is defined as those social work services that are offered in and through a religious congregation – a slum church in Chennai with the help and financial aid of the slum people and network with different stake holders. The topic itself is a new area for explosion. Social work collaboration with faith-based establishments, such as churches, has great potential to optimize internal functions and service to the community. Social Work has been practiced through churches as an expression of the love of Jesus Christ for many years. Social welfare programmes have been introduced through church mission agencies. The paper briefly presents about the background of the slum community, about the slum church and the methods applied as part of Congregational social work. Seven dimensions have been presented in this paper 1. Use of Appreciative Enquiry to discover the abilities of the community 2. Creation of Endowment fund for Education with the support of Slum people 3. Micro-Enterprise initiatives to provide job opportunities 4. Educational Initiatives 5. Exposure to Foreign countries for the slum people 6. Advocating and Lobbying for the rights of slum people 7. Shelter home during Natural disaster. This paper is based on personal experience of applying Social work in a congregation based in a slum community and the members belong to the same community. Keywords: Congregational Social Work, Church Social Work