A Two-Dimensional Mesh Refinement Method for Problems with One-Dimensional Singularities

This paper introduces a method for resolving internal layers that can occur in the solutions of time-dependent differential equations in two space dimensions. Singular features in these solutions that are essentially one-dimensional in nature but are not oriented with the computational mesh are resolved using one-dimensional mesh refinement techniques with a procedure that is similar to an ADI method. A careful interpolation procedure assures that the resolution obtained in each ADI step is not lost in the succeeding ADI step

Hydrologic Modeling Study to Determine Hydrologic Impact of Resacas on the Lower Laguna Madre Watershed

During a high intensity storm events, a series of catastrophic events occur. These catastrophic events include flooding and destruction of infrastructure. Engineers have determined a method to design for high intensity storms based off hydrologic analysis of previous storms. With this data engineers can determine the outflow of major rivers and streams that may impact infrastructure. By determining the watershed engineers can predict the flow of the water and as well as the location of the outfall. In the Rio Grande Valley, water quality is very important because after rain events stormwater from cities is carried out towards the Laguna Madre, which is home to an array on environmental habitats and wildlife. With the determination of the watershed boundaries of this region, engineers and environmentalists can use this data to determine where pollution source points that can affect the environment are located. This project will simulate the watershed boundaries for the region of the Lower Laguna Madre using ArcGIS in conjunction with the extension HEC-GeoHMS, a tool developed by the Hydrologic Engineering Core. With the use of a Digital Elevation Model (DEM) provided by the United States Geologic Survey, the watershed boundaries were delineated using both ArcGIS and the HEC-GeoHMS extension. These watershed boundaries were then compared to existing watershed boundaries in the region to check the validity. The Rio Grande Valley is considered a flat region that does not have a very erratic change in slope, it is also covered by a series of canals and streams; because of these factors found in the terrain, an exact delineation is hard to determine. With the completion of the watershed delineation and the development of the hydrologic model in the area will developed to simulate the impact of the resacas in the region

EEG Correlates of Song Prosody: A New Look at the Relationship between Linguistic and Musical Rhythm

Song composers incorporate linguistic prosody into their music when setting words to melody, a process called “textsetting.” Composers tend to align the expected stress of the lyrics with strong metrical positions in the music. The present study was designed to explore the idea that temporal alignment helps listeners to better understand song lyrics by directing listeners’ attention to instances where strong syllables occur on strong beats. Three types of textsettings were created by aligning metronome clicks with all, some or none of the strong syllables in sung sentences. Electroencephalographic recordings were taken while participants listened to the sung sentences (primes) and performed a lexical decision task on subsequent words and pseudowords (targets, presented visually). Comparison of misaligned and well-aligned sentences showed that temporal alignment between strong/weak syllables and strong/weak musical beats were associated with modulations of induced beta and evoked gamma power, which have been shown to fluctuate with rhythmic expectancies. Furthermore, targets that followed well-aligned primes elicited greater induced alpha and beta activity, and better lexical decision task performance, compared with targets that followed misaligned and varied sentences. Overall, these findings suggest that alignment of linguistic stress and musical meter in song enhances musical beat tracking and comprehension of lyrics by synchronizing neural activity with strong syllables. This approach may begin to explain the mechanisms underlying the relationship between linguistic and musical rhythm in songs, and how rhythmic attending facilitates learning and recall of song lyrics. Moreover, the observations reported here coincide with a growing number of studies reporting interactions between the linguistic and musical dimensions of song, which likely stem from shared neural resources for processing music and speech

On the smallest scale for the incompressible Navier-Stokes equations

It is proven that for solutions to the two- and three-dimensional incompressible Navier-Stokes equations the minimum scale is inversely proportional to the square root of the Reynolds number based on the kinematic viscosity and the maximum of the velocity gradients. The bounds on the velocity gradients can be obtained for two-dimensional flows, but have to be assumed to be three-dimensional. Numerical results in two dimensions are given which illustrate and substantiate the features of the proof. Implications of the minimum scale result to the decay rate of the energy spectrum are discussed

Total cross sections for positrons scattered elastically from helium based on new measurements of total ionization cross sections

An improved technique is presented for employing the 2.3m spectrometer to measure total ionization cross sections, Q sub ion, for positrons incident on He. The new ionization cross section agree with the values reported earlier. Estimates are also presented of total elastic scattering cross section, Q sub el, obtained by subtracting from total scattering cross sections, Q sub tot, reported in the literature, the Q sub ion and Q sub Ps (total positronium formation cross sections) and total excitation cross sections, Q sub ex, published by another researcher. The Q sub ion and Q sub el measured with the 3m high resolution time-of-flight spectrometer for 54.9eV positrons are in accord with the results from the 2.3m spectrometer. The ionization cross sections are in fair agreement with theory tending for the most part to be higher, especially at 76.3 and 88.5eV. The elastic cross section agree quite well with theory to the vicinity of 50eV, but at 60eV and above the experimental elastic cross sections climb to and remain at about 0.30 pi a sub o sq while the theoretical values steadily decrease

Overdamped van Hove function of atomic liquids

Using the generalized Langevin equation formalism and the process of contraction of the description we derive a general memory function equation for the thermal fluctuations of the local density of a simple atomic liquid. From the analysis of the long-time limit of this equation, a striking equivalence is suggested between the long-time dynamics of the atomic liquid and the dynamics of the corresponding \emph{Brownian} liquid. This dynamic equivalence is confirmed here by comparing molecular and Brownian dynamics simulations of the self-intermediate scattering function and the long-time self-diffusion coefficient for the hard-sphere liquid.Comment: 4 Figures, 23 page

Dilatometer Based Liquefaction Potential of Sites in the Imperial Valley

The liquefaction potential of several sites in the Imperial Valley, south California, is evaluated on the basis of standard penetration, cone, and dilatometer test data. The performance of the soil deposits at these sites during past earthquakes has been documented in earlier studies. Since the dilatometer parameter Kd is expected to reflect factors (e.g. fabric, prestress, preshaking, aging) affecting liquefaction potential to a certain extent (Marchetti, 1982), this paper primarily focuses on this parameter as an index for evaluating liquefaction potential. A tentative boundary curve (in terms of stress ratio vs. Kd) for evaluating liquefaction potential that takes advantage of earlier boundaries is proposed. A promising index which combines dynamic and static dilatometer tests is also proposed

The Relationship Between Self-Focus and Anxiety

Researchers have linked self-focus with multiple psychological disorders and forms of maladaptive cognition, such as anxiety and depression. Throughout their lifetime, around 33% of U.S. adults suffer from an anxiety disorder, making it the most prevalent mental illness in the country. Anxiety symptoms often co-occur with depressive symptoms, therefore depression and anxiety are often consolidated together in research scenarios. Past studies have shown a positive correlation between negative self-focus and depressive symptoms. However, with anxiety prevalence on the rise, it is worthy of attention independent from depression. This study will look at the relationship between anxiety and negative self-focus. Previous research has shown that anxiety is correlated with higher reports of self-focus, and more severe levels of anxiety are related to negative self-focus specifically. The present study examines self-focused responses on a language task in relation to anxiety. Additionally, this study will consider whether depression mediates the relationship between anxiety and negative self-focus, which has yet to be analyzed in the literature. The Sentence Completion Task (SCT) is an open-ended language task that typically provides participants with beginnings of sentences, known as stems , and participants then complete the sentences in ways that are meaningful to them. Responses to the SCT are coded for focus (e.g.. self, other, both, or neither) and valence (positive, negative, or neutral). A sample of 188 college students were recruited to complete the SCT and the Beck Anxiety Inventory (BAI). This study predicted that (1) a positive correlation exists between anxiety symptoms and amount of self-focus, (2) negative self-focus is related to higher anxiety levels, and (3) there will be a strong correlation between anxiety and negative self-focus once depression is controlled for. Interestingly, our results showed that anxiety did not correlate with self-focus (r(155)=.121, p=.130) or negative self-focus (r(155)=.071, p=.375), which does not support findings from previous studies. Since the results from our first two hypotheses were not significant, we did not test the correlation between anxiety and negative self-focus while controlling for depression. This study discusses possible reasons behind the non-significant findings, and suggests that future research could evaluate if anxiety has a strong relationship with external-focused attention

What’s A Quail Worth? A Longitudinal Assessment of Quail Hunter Demographics, Attitudes, and Spending Habits In Texas

Funds generated and spent on the pursuit of quail (Colinus virginianus, Callipepla squamata) hunting in Texas are sizable. We surveyed a population of quail hunters in Texas in 2000 and 2011 to assess hunter demographics and spending habits. The population of hunters for the 2000 survey consisted of members of Quail Unlimited who lived in Texas while the 2011 population consisted of the former group’s successor in Texas—Quail Coalition. The initial (2000) survey was a mail questionnaire while the 2011 survey instrument was delivered electronically. We achieved response rates of 47% in 2000 but only 9% in 2011. The number of resident quail hunters in Texas decreased 72% from 1981 to 2010. Quail hunters in Texas can be characterized as white males (97%) and affluent (65% reported annual household incomes above $125,000 in 2010). Survey respondents documented an average expenditure of$8,606 in pursuit of quail during an average of 8.8 days of hunting during the 2010–2011 season. This resulted in a cost of $254 per quail bagged when combined with harvest estimates provided by respondents; an estimated increase of 23% over the last 10 years