Understanding Current Signals Induced by Drifting Electrons

Consider an electron drifting in a gas toward a collection electrode. A common misconception is that the electron produces a detectable signal only upon arrival at the electrode. In fact, the situation is quite the opposite. The electron induces a detectable current in the electrode as soon as it starts moving through the gas. This induced current vanishes when the electron arrives at the plate. To illustrate this phenomenon experimentally, we use a gas-filled parallel plate ionization chamber and a collimated $^{241}$Am alpha source, which produces a track of a fixed number of ionization electrons at a constant distance from the collection electrode. We find that the detected signal from the ionization chamber grows with the electron drift distance, as predicted by the model of charge induction, and in conflict with the idea that electrons are detectable upon arrival at the collection plate.Comment: 21 pages, 12 figure

In Defense of Property

This Article responds to an emerging view, in scholarship and popular society, that it is normatively undesirable to employ property law as a means of protecting indigenous cultural heritage. Recent critiques suggest that propertizing culture impedes the free flow of ideas, speech, and perhaps culture itself. In our view, these critiques arise largely because commentators associate property with a narrow model of individual ownership that reflects neither the substance of indigenous cultural property claims nor major theoretical developments in the broader field of property law. Thus, departing from the individual rights paradigm, our Article situates indigenous cultural property claims, particularly those of American Indians, in the interests of peoples rather than persons, arguing that such cultural properties are integral to indigenous group identity or peoplehood, and deserve particular legal protection. Further, we observe that whereas individual rights are overwhelmingly advanced by property law\u27s dominant ownership model, which consolidates control in the title-holder, indigenous peoples often seek to fulfill an ongoing duty of care toward cultural resources in the absence of title. To capture this distinction, we offer a stewardship model of property to explain and justify indigenous peoples\u27 cultural property claims in terms of non-owners\u27 fiduciary obligations toward cultural resources. We posit that re-envisioning cultural property law in terms of peoplehood and stewardship more fully illuminates both the particular nature of indigenous claims and the potential for property law itself to embrace a broader and more flexible set of interests

MAP7 regulates axon morphogenesis by recruiting kinesin-1 to microtubules and modulating organelle transport.

Neuronal cell morphogenesis depends on proper regulation of microtubule-based transport, but the underlying mechanisms are not well understood. Here, we report our study of MAP7, a unique microtubule-associated protein that interacts with both microtubules and the motor protein kinesin-1. Structure-function analysis in rat embryonic sensory neurons shows that the kinesin-1 interacting domain in MAP7 is required for axon and branch growth but not for branch formation. Also, two unique microtubule binding sites are found in MAP7 that have distinct dissociation kinetics and are both required for branch formation. Furthermore, MAP7 recruits kinesin-1 dynamically to microtubules, leading to alterations in organelle transport behaviors, particularly pause/speed switching. As MAP7 is localized to branch sites, our results suggest a novel mechanism mediated by the dual interactions of MAP7 with microtubules and kinesin-1 in the precise control of microtubule-based transport during axon morphogenesis

Examining the Effectiveness of Explicit, Systematic Mathematics Vocabulary Instruction for Students with Learning Difficulties and Disabilities in a Specialized Setting

Many students in the United States are not proficient in mathematics. Mathematics vocabulary is one area that may impact students’ understanding of and engagement with mathematics. This dissertation investigated the implementation, effectiveness, and teacher’s perceptions of a program for teaching mathematics vocabulary necessary for fourth grade and beyond. This study randomly assigned 30 students (11-14 years old) to receive mathematics vocabulary instruction or not. Three teachers at a school for students with learning difficulties and disabilities administered mathematics vocabulary and mathematics achievement tests to all of their students before teaching the program to 17 of the students. A research assistant and I observed the teachers, and all of the teachers shared their perceptions of the lessons via a survey. Results show that the teachers taught the lessons as intended and that the students who received the lessons did better on the post-test than students who did not receive the lessons. Results from the survey suggest the teachers found the intervention acceptable, easy to use, and plan to use it or something similar to teach mathematics vocabulary in the future

Physical self efficacy, injury, history and locus of control as predictors of athletes\u27 expected recovery actions in response to various levels of injury severity

Athletes and coaches from a university athletic program at the highest level of competition in the National Collegiate Athletic Association and a college athletic program at the lowest level of competition participated in this project designed to study athletes expected recovery actions when presented with various levels of injury. Physical self-efficacy, locus of control and injury history were considered as mediators in the expected recovery processes including expected recovery time, the number of recovery strategies, and reaction to permission for competition after injury. The Physical Self-Efficacy Scale (Ryckman, Robbins, Thorton, & Cantrell, 1982) and the Nowicki-Strickland Locus of Control Scale for Children (Nowicki & Strickland, 1973, adapted for use with college students and adults), were determined to be related to an athlete\u27s predicted recovery actions from specific mild, moderate, and severe injury. Coaches were determined to have the ability to accurately categorize athletes regarding physical self-efficacy and locus of control. Athletes with an internal locus of control were found to predict different recovery actions from athletes with an external locus of control. Likewise, athletes with high physical self-efficacy were found to predict different recovery actions from athletes with a low physical self-efficacy. When athletes, who were classified as having both an internal locus of control and a high physical self-efficacy were compared to athletes classified as having both external locus of control and low self-efficacy, additional differences were observed. The athletes differed on ratings of their own ability, predictions of recovery times, and on level of awareness of the injury site after approval for competition. Repeated injuries were determined to increase extemality of locus of control of athletes. Previous experience with injury, the athlete\u27s perceived level of ability in sport, and the coach\u27s perceptions of the athlete\u27s response to injury were also considered for their predictive ability for injury recovery

Cannabinoid Withdrawal Produces Altered Somatic and Emotionality-related Behavior in Mice

Cannabis sativa is the most commonly abused illicit drug in the United States. An estimated 9 percent of those who use cannabis will develop some level of cannabinoid use disorder (CUD). Although behavioral therapy has some success in treating CUD, many users still relapse. Moreover, there are no FDA approved pharmacological treatments available to complement behavioral therapy. The need for appropriate treatments highlights the need for nonhuman animal models to test target compounds. The current study aimed to (1) evaluate the MAGL inhibitor JZL184 as a possible treatment for cannabinoid withdrawal, and (2) to develop a spontaneous model of cannabinoid withdrawal in mice. Mice were treated with the primary psychoactive component of cannabis, Delta 9-tetrahydrocannabinol (THC; 50 mg/kg) or vehicle for 5.5 days. On the 6th day, withdrawal was precipitated using the cannabinoid receptor antagonist rimonabant (3 mg/kg), and behavior was scored in marble burying and somatic signs tests. THC withdrawal significantly decreased marble burying, however, JZL184 pretreatment did not attenuate withdrawal-related changes marble burying. JZL184 attenuated withdrawal-induced somatic behaviors as demonstrated in previous studies. A second set of experiments was used to evaluate spontaneous (i.e., not precipitated) THC withdrawal, as measured through marble burying and somatic signs. THC withdrawal caused significant increases in paw tremors and head twitches 24--48 h after abstinence, and JZL184 significantly attenuated these somatic signs of withdrawal. These data support the use of endocannabinoid manipulation to reduce symptoms of THC withdrawal

Effects of Charter School Laws on Charter School Performance

Problem Statement Many issues exist in the public school system in the United States today. The main problems are: 1) American students are performing below their peers in other developed nations; 2) American high school graduates have trouble competing in the global economy; 3) Large achievement gaps exist between subgroups of American students. One of the many recommended policy solutions is to create charter schools to induce innovation and competition into the public school system. Research Question While many researchers have looked at charter school outcomes, few consider the effects of charter school laws on student achievement. My research question asks how various components of charter school laws affect the performance of charter school students relative to a matched sample of their traditional public school counterparts. Literature Review Research shows mixed reviews of charter school student performance. Comparability between states is often difficult due to variability between charter schools in each state. This study addresses that problem. Methodology This study looks at a sample of 1,153 matched pairs of charter school schools and traditional public schools. Differences in reading and math proficiency levels are reported for fourth graders whenever possible. A regression was estimated using the difference in proficiency levels between charter school students and their matched public school counterparts as the dependent variable. Independent variables pertained to state law components and other important school level variables. Key Results Allowing for multiple issuing authorities and some non certified teachers is associated with positive outcomes for charter school students. Being very flexible in the number of charter schools making new starts (as opposed to converting public schools to charter schools) and not requiring local support is associated with negative outcomes for charter school students. Some state monitoring of charter school staffing improves student outcomes. Recommendations States should ensure that they are allowing for innovation in schools while providing a basic oversight function. Results from this study should be replicated in the future to verify policy implications. Charter school researchers should control for the effects of charter school laws in future evaluations of charter school performance

HOW BLACK STUDENTS EXPERIENCE SCHOOL IN A PREDOMINANTLY WHITE SUBURBAN HIGH SCHOOL: A PHENOMENOLOGICAL STUDY TO EXAMINE STUDENT PERCEPTIONS OF SELF-EFFICACY, SENSE OF BELONGINGNESS, AND PERCEIVED EDUCATIONAL OPPORTUNITY

This study used critical race theory to examine the lived experiences of Black students attending a predominantly White, high-performing, suburban high school. The researcher used a phenomenological approach to examine student perceptions of sense of belongingness, self-efficacy, and educational opportunity. Eight students participated in a focus study group, and seven students participated in semi-structured individual interviews. The data analysis showed the students did not experience a sense of belongingness in their schools, but they did exhibit high levels of self-efficacy and felt they were provided the same educational opportunities as other students. Six themes emerged from this study: (a) Social Isolation, (b) School Responsibilities, (c) Self-Efficacy, (d) Racism, (e) Relationships, and (f) Academic Opportunity. The participants expressed their struggles attending a predominately White school, including social isolation, conforming to the majority to fit in, difficulty forming relationships with their peers, racism, battling Black stereotypes, and the emotional harm it caused them. They demonstrated high self-efficacy and Black pride, and developed coping strategies and resiliency to be academically successful. The participants valued the academic opportunity the school provided and felt prepared for college. Six areas of school improvement were identified by the participants to create equitable school experiences for all students: (a) evaluate curricula and instructional practices; (b) give students a voice; (c) combat racism in schools; (d) provide anti-bias and anti-racist education; (e) foster inclusivity and acceptance; and (f) increase diversity of faculty and staff. Recommendations for practice and research are discussed