1,931 research outputs found
A Guide to Integrate Plant Cover Data From Two different Methods
There is a lack of consensus on how to monitor (measure) plant cover in tidal marshes. Multiple methods exist to estimate plant cover, which can confound interpretation when making comparisons across methods. Here, we provide a novel and more accurate approach, building off of traditional data transformations designed to integrate the two most common methods: Point Intercept and Ocular Cover
Development and Monitoring of Revegetation Methods: Connecting Students with Restoration Activities at Awcomin Marsh
Five classes in a local elementary school participated in an effort to grow and plant high marsh and upper border vegetation at a salt marsh restoration site in spring 2005. Seeds of six marsh upper edge species were successfully germinated and grown into seedlings by third graders. The seedlings were planted by the students in late spring 2005, but only switchgrass and quackgrass plants appeared to have established and survived after one year. Mature shoots of three high marsh species planted by the third graders (salt hay, salt grass and black grass) established successfully and continue to proliferate. In addition, we assessed an experiment of cordgrass plantings performed by community volunteers in 2002. The experiment was designed to test the effectiveness of three planting techniques at a salt marsh restored by the excavation of old dredge spoil that had been colonized by common reed. After four growing seasons, Plug, Bare Root Shoot, and Seed Head planting techniques exhibited greater cover of cordgrass and total cover of vascular plants when compared with unplanted areas. Cover of perennial plants (e.g., cordgrass), which contributes directly to belowground soil development in salt marshes, dominated the planted plots. Cover of annual species dominated the unplanted plots. Planting cordgrass in areas where dredge spoils and common reed had been excavated from a historic marsh accelerated the development of native vegetation compared with unplanted areas. Performance and evaluation of the two sets of plantings has provided information about appropriate planting techniques for our region and has involved and educated the local community about the values of salt marsh to promote stewardship. Recommendations included the use of bare root shoot and seed head planting techniques where cordgrass is desired. Outside plots or a greenhouse may be needed for successful propagation of upper edge marsh species from seed, and a planting program that includes mature plants as well as seedlings is recommended to ensure success
A PHENOMENOLOGICAL STUDY TO UNDERSTAND THE TRANSFORMATION OF THE EDUCATION SYSTEM IN A RURAL MISSOURI HIGH SCHOOL IN THE WAKE OF THE COVID-19 PANDEMIC
The purpose of this phenomenological study was to explore the transformation of the education system in a rural-distant Missouri high school in the wake of the COVID-19 pandemic. Seven content-area educators participated in the study. Data was collected through interviews and archival documents. The data analysis revealed three themes: transition to virtual learning, the new classroom experience, and emotional impact. Within those themes, participants described specific institutional and curricular changes that were made, and the emotional impact that the COVID-19 teaching experience had on them. Results of the study indicated that teachers felt very alone navigating through all of the educational changes. As schools develop and revise emergency plans, they should consider including a teacher support system and open communication amongst teachers, staff, and administrators. As the COVID-19 pandemic continued, this study may serve as a foundation to compare changes that occurred in schools across the United States (U.S.), as well as any possible trends in the emotional impact on educators
Electrolysis-based diaphragm actuators
This work presents a new electrolysis-based microelectromechanical systems (MEMS) diaphragm actuator. Electrolysis is a technique for converting electrical energy to pneumatic energy. Theoretically electrolysis can achieve a strain of 136 000% and is capable of generating a pressure above 200 MPa. Electrolysis actuators require modest electrical power and produce minimal heat. Due to the large volume expansion obtained via electrolysis, small actuators can create a large force. Up to 100 µm of movement was achieved by a 3 mm diaphragm. The actuator operates at room temperature and has a latching and reversing capability
Integrated parylene-cabled silicon probes for neural prosthetics
Recent advances in the field of neural prosthetics have demonstrated the thought control of a computer cursor. This capability relies primarily on electrode array surgically implanted into the brain as an acquisition source of neural activity. Various technologies have been developed for signal extraction; however most suffer from either fragile electrode shanks and bulky cables or inefficient use of surgical site areas. Here we present a design and initial testing results from high electrode density, silicon based arrays system with an integrated parylene cable. The greatly reduced flexible rigidity of the parylene cable is believed to relief possible mechanical damages due to relative motion between a brain and its skull
Inversion of the body waves from the Borrego Mountain earthquake to the source mechanism
The generalized linear inverse technique has been adapted to the problem of determining an earthquake source model from body-wave data. The technique has been successfully applied to the Borrego Mountain earthquake of April 9, 1968. Synthetic seismograms computed from the resulting model match in close detail the first 25 sec of long-period seismograms from a wide range of azimuths. The main shock source-time function has been determined by a new simultaneous short period-long period deconvolution technique as well as by the inversion technique. The duration and shape of this time function indicate that most of the body-wave energy was radiated from a surface with effective radius of only 8 km. This is much smaller than the total surface rupture length or the length of the aftershock zone. Along with the moment determination of M_o = 11.2 × 10^(25) dyne-cm, this radius implies a high stress drop of about 96 bars. Evidence in the amplitude data indicates that the polarization angle of shear waves is very sensitive to lateral structure
Modeling motor responses of paraplegics under epidural spinal cord stimulation
Epidural spinal cord stimulation (SCS) is a promising therapy for spinal cord injury (SCI). This paper combines experimental data from epidurally-stimulated human paraplegic patients with computational models of SCS to identify the electric field features correlated with the patients' ability to stand. We locate the spinal cord regions most critical to stimulated standing and find that the most informative stimulating features agree with results from nerve fiber theory. Further applications of our work include developing algorithms to optimize stimulation configurations for SCI patients, determining optimal electrode placement, and considering novel electrode array designs
On the periodic motions of simple hopping robots
Discrete dynamical systems theory is applied to the analysis of simplified hopping robot models. A one-dimensional vertical hopping model that captures both the vertical hopping dynamics and nonlinear control algorithm is reviewed. A more complicated two-dimensional model that includes both forward and vertical hopping dynamics and a foot placement algorithm is presented. These systems are analyzed using a Poincare return map and hopping behavior is investigated by constructing the return map bifurcation diagrams with respect to system parameters. The diagrams show period doubling leading to chaotic behavior. Using the vertical model results as a guide, dynamic behaviour of the planar hopping system is interpreted
On a nonstandard two-parametric quantum algebra and its connections with and
A quantum algebra associated with a nonstandard
-matrix with two deformation parameters is studied and, in
particular, its universal -matrix is derived using Reshetikhin's
method. Explicit construction of the -dependent nonstandard -matrix
is obtained through a coloured generalized boson realization of the universal
-matrix of the standard corresponding to a
nongeneric case. General finite dimensional coloured representation of the
universal -matrix of is also derived. This
representation, in nongeneric cases, becomes a source for various
-dependent nonstandard -matrices. Superization of leads to the super-Hopf algebra . A contraction
procedure then yields a -deformed super-Heisenberg algebra
and its universal -matrix.Comment: 17pages, LaTeX, Preprint No. imsc-94/43 Revised version: A note added
at the end of the paper correcting and clarifying the bibliograph
- …