984 research outputs found
Tango or More - From California\u27s Lesson 9 to the Constitutionality of a Gay-Friendly Curriculum in Public Elementary Schools
In August 2009, a group of parents in California filed a lawsuit, Balde v. Alameda Unified School District, in the Superior Court of California, County of Alameda. They alleged that the Alameda Unified School District refused them the right to excuse their children from a new curriculum, Lesson 9, that would teach public elementary school children about gay, lesbian, bisexual and transgender (GLBT) families. The proposed curriculum included short sessions about GLBT people, incorporated into more general lessons about family and health, once a year from kindergarten through fifth grade. Kindergarteners would learn the harms of teasing, while fifth graders would study sexual orientation stereotypes. One parent alleged that, although an overwhelming majority of parents spoke out against CLBT instruction at numerous school board meetings, the board chairman repeatedly told the public that the curriculum was evenly supported and opposed. Parents suspected the board had a preconceived political agenda behind the proposal. Other parents expressed their full support for the proposed curriculum because, noting that the school is a reflection of the community and the world, children from a very early age should see what the world is like. The parents\u27 petition for a writ of mandamus to require the school district to excuse their children from Lesson 9 was denied by the Court on December 1, 2009, and the pleadings filed do not claim any violation of the children\u27s rights under the Constitution. This Article studies the constitutionality of Lesson 9 in California public elementary schools
Axiomatic design of a customizable pneumatic automotive suspension with hydraulic ride height regulator
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2005."May 2005."Includes bibliographical references (leaf 15).Stiffness has long since governed the way people choose automobiles. Stiffer suspensions allow for the better handling necessary in sporty cars while softer suspensions provide the comfort expected in luxury cars. Automobiles have also been limited by ride height: a higher ride height will yield more clearance from bumps along the ground. However, lower ride height lowers the center of gravity of the car, which is desired for safety. The purpose of this work is to propose a way of using axiomatic design to device a system that uses orifice controlled dampers, pneumatic springs and hydraulic chambers to achieve a fully customizable suspension system and ride height regulation. In addition, a way to create the best possible user experience is proposed by using control theory to keep the car chassis at the same level at all times, thus giving the user the ability to have a smooth ride at any suspension setting, even stiff suspension systems in the case of sporty car settings. To achieve the goals of this work, a short-long arm (SLA) suspension system was modeled and modified. The SLA suspension system is the most common front wheel independent suspension system that is used today.(cont.) By keeping a similar overall design for the proposed system, adaptability of the proposed system is increased. The coil spring of the common SLA suspension system is replaced by an air spring with a fluid chamber in series. The air spring has a variable spring stiffness that is related to the volume of air inside. Because air is compressible, the volume changes with the force applied, yielding a nonlinear relationship that must be compensated for by an active control system that monitors the overall volume of the air spring and compensates for any changes during use by addition or removal of air. The fluid chamber is responsible for keeping the chassis at the same level at all times by taking into account the changing volume of the air spring and the changes in the road by having incompressible fluid pumped in and out of the chamber.by Amy L. Wong.S.B
Determining the dominant degradation mechanisms in Nitrocellulose
Nitrocellulose (NC) is the base component for many modern day propellants and explosives, as well as for everyday items such as printing inks, paint and lacquer coatings. Despite its early beginnings as the first man-made plastic, the decomposition pathways from the bulk material to the products observed from its ambient ageing are still not fully understood. Knowledge of these processes are of critical importance when considering the conservation of NC artefacts, refinement of product formulations, predictions of shelf life and safety improvements. In this study, the dominant degradation pathways of NC were investigated using quantum mechanics (QM) methods to probe the mechanisms leading to the initial cleavage of nitrate groups from the cellulosic backbone. The NC structure was truncated from a polymer chain to monomer, dimer and trimer units. Density functional theory methods (DFT) were used to study the mechanistic detail at individual nitrate sites. Comparison of differently sized units using the quantum theory of atoms in molecules (QTAIM), analysis of the electrostatic potential (ESP) surface and partial charges showed that the most suitable approximation for study of the decomposition reactions was the β-glucopyranose monomer, bi-capped with methoxy groups. The primary thermolytic and hydrolytic denitration routes were explored using transition state (TS) searches and potential energy surface (PES) scans. It was found that the thermolytic behaviour of the NC denitration step matched that of a well studied nitrate ester, pentaerythritol tetranitrate (PETN). The hydrolytic scheme for nitrate cleavage was studied, finding that protonation at the bridging oxygen site was the most likely to lead to denitration. It was not possible to isolate a TS for the hydrolytic reaction, though a number of coordination schemes were tested. Key secondary processes beyond nitrate cleavage were examined to determine the fate of nitrogen in the system and the cause of the transition from a first order reaction rate to autocatalytic decomposition. The energies of reactions in three different decomposition schemes proposed in literature were compared. Ethyl nitrate was used as a test system before extension to the NC monomer. New reaction pathways for decomposition were constructed using the reactions posed in the literature studies. The new schemes revealed that •NO2 was the most likely cause for the experimentally observed autocatalytic rate of degradation
Evaluation of waste materials for pollutant removal
This study was conducted to assess the capability of three waste materials in removing pollutants from synthetic and real wastewater samples. Column experiments with single (egg shells, shrimp shells and coal) and mixed medium (egg shells and coal; shrimp shells and coal) were carried out at room temperature. The removal efficiencies of TSS, PO4 3-, NH3-N, NO3-N, COD and heavy metals (Cd, Zn and Pb) were determined. All the waste materials showed good capability in removing heavy metals (Cd, Zn and Pb) from synthetic and real wastewater with removal efficiencies ranged between 90-100%. Of all the waste materials
studied, egg shells showed the best adsorption and removal capability and this was supported by Langmuir adsorption studies using synthetic wastewater which revealed that egg shells had better capability in removing Cd (II) and Pb (II) ions compared to other waste materials. The influence of particle sizes for all single medium except shrimp shells was pursued and results showed that the smaller the particle size, the better is the removal capability of the waste materials except for the removal of COD using eggs shells. Egg shells with particle size 2 mm (18.67%) showed higher COD removal compared to 1 mm particle size (14.67%). However, statistical analysis showed that there was no significant difference in the removal by the two particle sizes. Waste materials also reduced the concentrations of TSS, PO4 3-, NH3-N, NO3-N, COD and
heavy metals in real wastewater. Results of this study showed the effectiveness and feasibility of the proposed waste materials as treatment medium for wastewater
Student Physical Activity Patterns: Grade, Gender, and Activity Influences
The purpose of this study was to determine how physical education students\u27 cardiovascular responses as determined by mean heart rate, standard deviation of heart rate, and percentage of time in target heart rate zone varied according to student characteristics. Participants were 505 students in Grades 3 through 12. The Polar Accurex Plus heart rate telemetry system was used to measure the physiological load on the cardiovascular system. Three-way ANOVA results suggested that heart rate patterns in physical education varied according to gender, grade, and activity. For example, secondary school girls were more active in individual activities while secondary school boys were more active in team sport activities. Elementary students were the most active group and had the most variability in their heart rate patterns
Social Geographies at Play: Mapping the Spatial Politics of Community-Based Youth Sport Participation
Organized youth sports programs (YSP) provide opportunities for participation in physical activity, and represent an important part of the broader public health agenda in the U.S. YSP not only provide physiological health benefits through active participation, but also promote social relationships within communities. In this study, we (1) investigated participants’ travel to access YSP located in neighborhoods historically delineated by an over/under-representation of socio-economic and/or racial diversity; and (2) examined the neighborhood demographics for those YSP participants who traveled the most/least to participate. Five years of demographic and GIS visualization data from participants in a publically-provisioned youth sport league network were analyzed. Significant differences were found between the travel distances of participants in different sports, and between the travel distances of participants from neighborhoods with different racial and/or socio-economic composition. This research expands understanding of the potential segregation effects of community-based YSP for various stakeholder groups
A Two-Step Approach for Narrowband Source Localization in Reverberant Rooms
This paper presents a two-step approach for narrowband source localization
within reverberant rooms. The first step involves dereverberation by modeling
the homogeneous component of the sound field by an equivalent decomposition of
planewaves using Iteratively Reweighted Least Squares (IRLS), while the second
step focuses on source localization by modeling the dereverberated component as
a sparse representation of point-source distribution using Orthogonal Matching
Pursuit (OMP). The proposed method enhances localization accuracy with fewer
measurements, particularly in environments with strong reverberation. A
numerical simulation in a conference room scenario, using a uniform microphone
array affixed to the wall, demonstrates real-world feasibility. Notably, the
proposed method and microphone placement effectively localize sound sources
within the 2D-horizontal plane without requiring prior knowledge of boundary
conditions and room geometry, making it versatile for application in different
room types
Impact of Probe Substrate Selection on Cytochrome P450 Reaction Phenotyping Using the Relative Activity Factor
ABSTRACT Accurately assessing the contribution of cytochrome P450 (P450) isoforms to overall metabolic clearance is important for prediction of clinical drug-drug interactions (DDIs). The relative activity factor (RAF) approach in P450 reaction phenotyping assumes that the interaction between P450-selective probes and testing systems is the same as the interaction of drug candidate with those systems. To test this assumption, an intersystem clearance ratio (ICR) was created to evaluate the difference in values between RAF-scaled intrinsic clearance (CL int ) and measured CL int in human liver microsomes (HLMs). The RAF value for CYP3A4 or CYP2C9 derived from a particular P450-selective probe reaction was applied to calculate RAF-scaled CL int for other probe reactions of the same P450 isoform in a crossover manner and compared with the measured HLM CL int . When RAF derived from midazolam or nifedipine was used for CYP3A4, the ICR for testosterone 6b-hydroxylation was 31 and 25, respectively, suggesting significantly diverse interactions of CYP3A4 probes with the testing systems. Such ICR differences were less profound among probes for CYP2C9. In addition, these RAF values were applied to losartan and meloxicam, whose metabolism is mostly CYP2C9 mediated. Only using the RAF derived from testosterone for CYP3A4 produced the expected CYP2C9 contribution of 72%-87% and 47%-69% for metabolism of losartan and meloxicam, respectively. RAF derived from other CYP3A4 probes would have attributed predominantly to CYP3A4 and led to incorrect prediction of DDIs. Our study demonstrates a significant impact of probe substrate selection on P450 phenotyping using the RAF approach, and the ICR may provide a potential solution
Perkembangan Industri Minyak dan Gas Sabah (1881–1980): Penelitian Terhadap Eksplorasi di Laut China Selatan
Kajian ini memfokuskan tentang eksplorasi minyak dan gas di Laut China Selatan (LCS) dari tahun 1881 ketika British North Borneo Company (BNBC) mentadbir Borneo Utara dan terbatas sehingga pengenalan Dasar Kabotaj Negara (Malaysia) pada 1 Januari 1980. Rentetan sejarah yang menarik berkenaan eksplorasi minyak dan gas Sabah perlu diamati semula khususnya setelah Petroliam Nasional Berhad atau Petronas ditubuhkan pada tahun 1974 yang membolehkan Sabah dibekalkan dengan sumber minyak dan gas yang dihasilkan dari telaga luar pantai Sabah pada tahun 1980. Kajian ini banyak bergantung kepada sumber primer dalam bentuk dokumen rasmi, laporan dan akhbar yang diperolehi dari Arkib Negeri Sabah (ANS), Malaysia. Kajian mendapati bahawa walaupun percubaan eksplorasi minyak Borneo Utara atau Sabah kemudiannya telah dilaksanakan oleh BNBC semenjak tahun 1881, kegiatan tersebut hanya diperkukuh selepas tamat tempoh pendudukan Jepun. Perkembangan ini semakin ketara apabila berlaku perubahan dalam sistem antarabangsa yang bersifat rule-based yakni pengenalan undang-undang kelautan bermula dari tahun 1950-an yang telah memberi peluang kepada British dan kerajaan Sabah, melalui pelbagai syarikat yang dilantik, untuk menjalankan eksplorasi minyak ke kawasan luar pantai di LCS. Kegiatan cari gali minyak sehingga ke kawasan LCS terbukti membuahkan hasil khususnya dalam memakmurkan ekonomi Malaysia
Perkembangan industri minyak dan gas Sabah (1881-1980): Penelitian terhadap eksplorasi di Laut China Selatan
This study focuses on oil and gas exploration in the South China Sea (SCS) from the period of the British North Borneo Company’s (BNBC) administration of North Borneo in 1881 until the introduction of the National Cabotage Policy (Malaysia) on 1st January 1980. The interesting history of Sabah’s oil and gas exploration needs to be revisited especially following the establishment of Petroliam Nasional Berhad or Petronas in 1974 which has enabled Sabah to be supplied with oil and gas resources produced from the offshore wells in 1980. This analysis relies heavily on primary sources in the form of official documents, reports and newspapers obtained from the Sabah State Archives (SSA), Malaysia. The study found that, although oil exploration of North Borneo or Sabah was initially carried out by BNBC since 1881, it was only strengthened after the end of the Japanese occupation. This development became more pronounced following the changes in the rule-based international system, notably the introduction of maritime law starting from the 1950s, which provided opportunities to both the British and Sabah governments through various companies, to conduct offshore oil exploration in the SCS. Oil exploration activities in the SCS area have proven to be lucrative, especially in terms of its contribution to the Malaysian economy
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