From Homeschool to the Community College: A Multiple Case Study

The number of U.S. homeschooled students has steadily risen from the 1980\u27s to the present, and many eventually choose to attend community colleges (Cogan, 2010; Mason, 2004; Ray, 2004a; Sorey & Duggan, 2008a). Homeschoolers who make community colleges their first structured educational setting outside the home do so for various reasons: (a) to obtain skills to prepare for a chosen career path or educational goal; (b) for economic reasons; and (c) to stay close to home (Ray, 2004b; Sorey & Duggan, 2008a). Presently, limited research explores the homeschooled population\u27s transition during the first year of college experience. Community colleges are very different educational settings from four year colleges (AACC, 2012). A comprehensive examination of community college homeschooled student transition is needed. Tinto\u27s theory of college adjustment served as the theoretical framework for a multiple case study of three community college students who completed secondary school as homeschoolers. This study describes how they transitioned from the home environment to a mid-sized, Mid Atlantic community college setting, using Tinto\u27s framework of separation, transition, and incorporation. (Tinto, 1993, 1997). While one student definitely achieved incorporation, it can be argued that the remaining students showed signs of incorporation by the conclusion of the study. The data collection used in this study consisted of interviews, observations, journal analysis, and finally, a focus group. The participants found services such as academic advising, disabilities services, and many teachers and classmates to be helpful to them. The participants overcame challenges including medical conditions, demanding curricula, and relocating while attending Mid Atlantic Community College. Recommendations for recruiting homeschooled students include online, community, and campus initiatives. Some suggestions for campus initiatives included may also serve to retain homeschooled students. Future research should examine many aspects of homeschooling community college student populations, such as demographics, work/school interactions, homeschooling approaches, and faith-based comparisons

On the Apparent Nulls and Extreme Variability of PSR J1107-5907

We present an analysis of the emission behaviour of PSR J1107-5907, a source known to exhibit separate modes of emission, using observations obtained over approximately 10 yr. We find that the object exhibits two distinct modes of emission; a strong mode with a broad profile and a weak mode with a narrow profile. During the strong mode of emission, the pulsar typically radiates very energetic emission over sequences of ~200-6000 pulses (~60 s-24 min), with apparent nulls over time-scales of up to a few pulses at a time. Emission during the weak mode is observed outside of these strong-mode sequences and manifests as occasional bursts of up to a few clearly detectable pulses at a time, as well as low-level underlying emission which is only detected through profile integration. This implies that the previously described null mode may in fact be representative of the bottom-end of the pulse intensity distribution for the source. This is supported by the dramatic pulse-to-pulse intensity modulation and rarity of exceptionally bright pulses observed during both modes of emission. Coupled with the fact that the source could be interpreted as a rotating radio transient (RRAT)-like object for the vast majority of the time, if placed at a further distance, we advance that this object likely represents a bridge between RRATs and extreme moding pulsars. Further to these emission properties, we also show that the source is consistent with being a near-aligned rotator and that it does not exhibit any measurable spin-down rate variation. These results suggest that nulls observed in other intermittent objects may in fact be representative of very weak emission without the need for complete cessation. As such, we argue that longer (> 1 h) observations of pulsars are required to discern their true modulation properties.Comment: 15 pages, 10 figures, accepted for publication in MNRA

Feedback Control for Systems with Uncertain Parameters Using Online-Adaptive Reduced Models

We consider control and stabilization for large-scale dynamical systems with uncertain, time-varying parameters. The time-critical task of controlling a dynamical system poses major challenges: using large-scale models is prohibitive, and accurately inferring parameters can be expensive, too. We address both problems by proposing an offine-online strategy for controlling systems with time- varying parameters. During the offine phase, we use a high-fidelity model to compute a library of optimal feedback controller gains over a sampled set of parameter values. Then, during the online phase, in which the uncertain parameter changes over time, we learn a reduced-order model from system data. The learned reduced-order model is employed within an optimization routine to update the feedback control throughout the online phase. Since the system data naturally reects the uncertain parameter, the data-driven updating of the controller gains is achieved without an explicit parameter estimation step. We consider two numerical test problems in the form of partial differential equations: a convection-diffusion system, and a model for ow through a porous medium. We demonstrate on those models that the proposed method successfully stabilizes the system model in the presence of process noise.DARPA EQUiPS program (award number UTA15-001067)United States. Department of Energy. Office of Advanced Scientific Computing Research (grant DE-FG02-08ER2585)United States. Department of Energy. Office of Advanced Scientific Computing Research (grant DE-SC000929

Where should livestock graze? Integrated modeling and optimization to guide grazing management in the Cañete basin, Peru

Integrated watershed management allows decision-makers to balance competing objectives, for example agricultural production and protection of water resources. Here, we developed a spatially-explicit approach to support such management in the Cañete watershed, Peru. We modeled the effect of grazing management on three services – livestock production, erosion control, and baseflow provision – and used an optimization routine to simulate landscapes providing the highest level of services. Over the entire watershed, there was a trade-off between livestock productivity and hydrologic services and we identified locations that minimized this trade-off for a given set of preferences. Given the knowledge gaps in ecohydrology and practical constraints not represented in the optimizer, we assessed the robustness of spatial recommendations, i.e. revealing areas most often selected by the optimizer. We conclude with a discussion of the practical decisions involved in using optimization frameworks to inform watershed management programs, and the research needs to better inform the design of such programs

Core Actuation Promotes Self-Manipulability on a Direct-Drive Quadrupedal Robot

For direct-drive legged robots operating in unstructured environments, workspace volume and force generation are competing, scarce resources. In this paper we demonstrate that introducing geared core actuation (i.e., proximal to rather than distal from the mass center) increases workspace volume and can provide a disproportionate amount of work-producing force to the mass center without affecting leg linkage transparency. These effects are analytically quantifiable up to modest assumptions, and are demonstrated empirically on a spined quadruped performing a leap both on level ground and from an isolated foothold (an archetypal feature of unstructured terrain)