Low thrust orbit determination program

Logical flow and guidelines are provided for the construction of a low thrust orbit determination computer program. The program, tentatively called FRACAS (filter response analysis for continuously accelerating spacecraft), is capable of generating a reference low thrust trajectory, performing a linear covariance analysis of guidance and navigation processes, and analyzing trajectory nonlinearities in Monte Carlo fashion. The choice of trajectory, guidance and navigation models has been made after extensive literature surveys and investigation of previous software. A key part of program design relied upon experience gained in developing and using Martin Marietta Aerospace programs: TOPSEP (Targeting/Optimization for Solar Electric Propulsion), GODSEP (Guidance and Orbit Determination for SEP) and SIMSEP (Simulation of SEP)

Resonance between Noise and Delay

We propose here a stochastic binary element whose transition rate depends on its state at a fixed interval in the past. With this delayed stochastic transition this is one of the simplest dynamical models under the influence of ``noise'' and ``delay''. We demonstrate numerically and analytically that we can observe resonant phenomena between the oscillatory behavior due to noise and that due to delay.Comment: 4 pages, 5 figures, submitted to Phys.Rev.Lett Expanded and Added Reference

TEAMwork: Testing Emotional Attunement and Mutuality During Parent-Adolescent fMRI.

The parent-child relationship and family context influence the development of emotion regulation (ER) brain circuitry and related skills in children and adolescents. Although both parents' and children's ER neurocircuitry simultaneously affect how they interact with one another, neuroimaging studies of parent-child relationships typically include only one member of the dyad in brain imaging procedures. The current study examined brain activation related to parenting and ER in parent-adolescent dyads during concurrent fMRI scanning with a novel task - the Testing Emotional Attunement and Mutuality (TEAM) task. The TEAM task includes feedback trials indicating the other dyad member made an error, resulting in a monetary loss for both participants. Results indicate that positive parenting practices as reported by the adolescent were positively correlated with parents' hemodynamic activation of the ventromedial prefrontal cortex, a region related to empathy, during these error trials. Additionally, during feedback conditions both parents and adolescents exhibited fMRI activation in ER-related regions, including the dorsolateral prefrontal cortex, anterior insula, fusiform gyrus, thalamus, caudate, precuneus, and superior parietal lobule. Adolescents had higher left amygdala activation than parents during the feedback condition. These findings demonstrate the utility of dyadic fMRI scanning for investigating relational processes, particularly in the parent-child relationship

Always on my mind: Cross-brain associations of mental health symptoms during simultaneous parent-child scanning.

How parents manifest symptoms of anxiety or depression may affect how children learn to modulate their own distress, thereby influencing the children's risk for developing an anxiety or mood disorder. Conversely, children's mental health symptoms may impact parents' experiences of negative emotions. Therefore, mental health symptoms can have bidirectional effects in parent-child relationships, particularly during moments of distress or frustration (e.g., when a parent or child makes a costly mistake). The present study used simultaneous functional magnetic resonance imaging (fMRI) of parent-adolescent dyads to examine how brain activity when responding to each other's costly errors (i.e., dyadic error processing) may be associated with symptoms of anxiety and depression. While undergoing simultaneous fMRI scans, healthy dyads completed a task involving feigned errors that indicated their family member made a costly mistake. Inter-brain, random-effects multivariate modeling revealed that parents who exhibited decreased medial prefrontal cortex and posterior cingulate cortex activation when viewing their child's costly error response had children with more symptoms of depression and anxiety. Adolescents with increased anterior insula activation when viewing a costly error made by their parent had more anxious parents. These results reveal cross-brain associations between mental health symptomatology and brain activity during parent-child dyadic error processing

Influences on achieving motor milestones: A twin-singleton study

In order to determine if twinning impacted achievement of motor milestones the attainment of early motor milestones in twins was examined and compared to published data from singletons of the same age from the same culture and birth years. We examined the influence of twinning, sex, zygosity and birth cohort (1987-2001) on the motor development of twins aged 0 to 24 months. Data on the attainment of motor milestones (turn, sit, crawl, stand and walk) of twins were collected from maternal reports. All data were corrected for gestational age. Data from the twin sample were compared to normative data from singletons, which were available from Child Health Clinics (CHC). Analyses across twin data and the CHC singleton data revealed no differences between twins and singletons in achievement of motor milestones. Girls were able to sit without support slightly earlier than boys, otherwise there were no other sex differences. Birth-order analyses revealed minimal but significant differences in turning over from back to belly and for sitting without support between the first- and second-born. Dizygotic (DZ) twins were faster than monozygotic (MZ) twins in achieving the moment of sit, crawl, stand and walk. Twins born in earlier cohorts were faster in reaching the moment of crawl, sit and walk. It is concluded that there are no differences in time of reaching motor milestones between twins and singletons within the normal range. Sex has minimal to no effect on motor development in early childhood. DZ twins achieve motor milestones sooner than MZ twins. Attainment of gross motor milestones (crawl, stand and walk) is delayed in later birth cohorts

VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196

We present results from multiwavelength observations of the BL Lacertae object 1ES 1741+196, including results in the very-high-energy $\gamma$-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well-modelled by a power law with a spectral index of $2.7\pm0.7_{\mathrm{stat}}\pm0.2_{\mathrm{syst}}$. The integral flux above 180 GeV is $(3.9\pm0.8_{\mathrm{stat}}\pm1.0_{\mathrm{syst}})\times 10^{-8}$ m$^{-2}$ s$^{-1}$, corresponding to 1.6% of the Crab Nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state.Comment: 8 pages, 5 figures. Accepted for publication in MNRA

Investigating the TeV Morphology of MGRO J1908+06 with VERITAS

We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away.Comment: To appear in ApJ, 8 page

Effects of Distillers Dried Grains with Solubles Sources and Soybean Meal Level on Growth Performance of Late Nursery Pigs

Two experiments were conducted to determine the effects of distillers dried grains with solubles (DDGS) source and soybean meal (SBM) level on growth performance of late nursery pigs. A total of 1,064 and 1,011 pigs (PIC 280 × 1050), initially 23.1 and 24.1 lb body weight (BW), were used in Exp. 1 and 2, respectively, with 21 to 27 pigs per pen. For approximately 21 days after weaning, pigs were fed common phase 1 and 2 diets. Then, pens were assigned to treatments in a randomized complete block design. There were 6 treatments in each experiment with 7 pens per treatment. Treatments 1 to 5 were replicated in Exp. 1 and 2, whereas treatment 6 was fed only in Exp. 1 and treatment 7 was fed only in Exp. 2. Treatments 1 to 3 consisted of diets with 23% conventional DDGS (Valero, Aurora, SD) and 21, 27, or 35% SBM. Treatments 4 and 5 were corn-SBM-based diets with 27 or 35% SBM. Treatment 6 consisted of a corn-SBM-based diet with 20% high protein DDGS (HP DDGS; Purestream 40, Lincolnway Energy, LLC, Nevada, IA) replacing the 23% conventional DDGS with the same amount of SBM (21%) as treatment 1 and same neutral detergent fiber (NDF) as treatment 2. Finally, treatment 7 consisted of a diet similar to treatment 2 but with 23% Lincolnway DDGS (Lincolnway Energy, LLC, Nevada, IA) replacing the 23% conventional DDGS. Data were analyzed with the GLIMMIX procedure of SAS. There was no evidence for treatment × experiment interactions, thus data from treatments 1 to 5 were combined. In Exp. 1, pigs fed diets containing HP DDGS had decreased (P \u3c 0.01) average daily gain (ADG) and poorer (P \u3c 0.01) feed-to-gain ratio (F/G) compared to pigs fed diets with conventional DDGS at the same NDF level, conventional DDGS at the same SBM level, or corn-SBM diet. In Exp. 2, there was no evidence for differences (P \u3e 0.10) in performance of pigs fed diets with Lincolnway DDGS or conventional DDGS. Feeding diets with 23% conventional DDGS decreased (P = 0.033) average daily feed intake (ADFI) and improved (P = 0.033) F/G compared to corn-SBM-based diets. Finally, ADG increased (linear, P = 0.001) and F/G improved (quadratic, P = 0.007) as SBM level increased from 21 to 35%. In conclusion, decreased growth performance indicates that the nutrient profile of the HP DDGS may have been overestimated. The net energy of conventional and Lincolnway DDGS seemed to be underestimated due to the improved F/G compared to corn-SBM diets. Finally, feeding diets with increasing SBM resulted in improved growth performance in late nursery pigs