Pennsylvania public schools: The fiscal landscape. A descriptive analysis 2008-2013

Perrin, Jason C The Pennsylvania State University ProQuest Dissert 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This research study examined public school district responses in Pennsylvania, through analysis of fiscal patterns, given decreased revenues and increased mandatory expenditures from 2008-2013. This descriptive quantitative study examined both revenues and expenditures for the aggregate group of Pennsylvania school districts and further explores fiscal patterns by average wealth through the use of deciles. The study was organized around the following four research questions: (1) How did school district revenues change? (2) How did school district expenditures change? (3) Did revenues and expenditure patterns vary by wealth? (4) What were the major legislative events in education and fiscal factors that occurred during this time period and how did they impact the fiscal pattern for revenues and expenditures?. The methodology used was primarily quantitative incorporating descriptive statistics specific to revenue and expenditure data from 2008-2013. Fiscal data was collected from the Pennsylvania Department of Education web site for all five hundred public school districts in the state. Secondary sources were also utilized to determine the impact of policy, legislative actions, and overall economic variables on fiscal elements specific to the public school finance landscape during the period of study. Analysis of key fiscal elements and secondary information was completed for all public school districts and further examined by average district wealth through decile information. This study found that between 2008-2013, fiscal responses and patterns changed due to revenue and expenditure variables for the aggregate group of Pennsylvania districts and differed for these districts based on average wealth. Key findings of this study included: (1) State policy decisions and legislative actions, specifically the reduction of state funding and lack of full restoration that coincided with the infusion and elimination of federal ARRA funding, had adverse effects on total school district revenues, especially 2011-12. (2) The recession of 2007-2009, along with limitations on local real estate tax increases imposed by Act 1 of 2006, restricted the ability for school districts to raise local revenue in order to counterbalance state revenue decreases, especially in 2011-12 when the Act 1 base index reached a five year low of 1.4%. (3) Increased benefit expenditures, due primarily to increased mandatory payments to PSERS, constrained the ability for school districts to meet overall obligations and forced challenging decisions, especially from 2011-13, when employer contribution rates increased from 5.54% to 12.36%. (4) State policy decisions and legislative actions, with regards to the interaction of state and federal revenues, adversely affected poorer districts to a greater degree than wealthy districts, counter to the intent of how those revenues were designed to be allocated. (5) The decrease of total revenue and increase of mandatory expenditures, specific to benefits, adversely affected poorer districts to a greater degree than wealthy districts, in the ability to meet rising costs associated with staff, more often forcing decisions fiscally necessary, but not educationally sound. (6) With mandatory expenditures projected to rise, as employer contribution rates to PSERS continues to rise, school districts will face further challenges in the future in an Act 1 environment, unless future policy and legislative actions provide relief in the form of increased state funding, equitable allocation and overall pension reform. Findings assert that long-range fiscal planning is paramount when addressing school district fiscal needs and that managing costs such as collective bargaining agreements and competing in a choice environment, given Charter School Costs, are important in managing the balance between revenues and expenditures. Future research aligned to further exploration of legislative impacts on school funding along with possible reform efforts specific to the state pension system and revenue generated through local real estate taxes will emerge in the coming years as key focus areas for understanding and practice.

The effect of an educational intervention on small cheese operations: An exploratory study

Machado, Robson A. M The Pennsylvania State University ProQuest Dissert 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The history of dairy is intertwined with our own origins. The processing of milk for cheesemaking was a critical development in early agriculture. Cheesemaking allows for the preservation of milk into a non-perishable and transportable form, and makes it more digestible. After the first cattle were introduced in the United States (U.S.) in the early 1600s, along with the first dairy breeds in the 1800s, mass production of dairy products began with the movement of people from the farms to the cities at the turn of the 20th century. Total milk production steadily increased after the mid-1970s in the U.S., with the parallel increase in milk production per cow. Meanwhile, average cow numbers per farm in the U.S. have decreased with many cows are now concentrated on larger farms. Following the increase in milk production, cheese production also has increased over the last several decades, with the U.S. becoming the top producer. In 2014, Pennsylvania was the sixth producer in the country, with 304 dairies holding Pennsylvania Department of Agriculture (PDA) dairy permits, of which 133 are cheese manufacturing permits. Most of the state's dairy facilities are small-scale, family-oriented businesses with less than five employees. These farms, where the cheesemaker has numerous responsibilities, might find it difficult to have the cheesemaker and other food handlers leave the farm for extended periods of time for food safety training. Given that foodborne diseases are a major health problem in the U.S. and cheese has been involved in foodborne disease outbreaks, the lack of food safety and sanitation training for this audience may pose a risk to consumers. To date, no training program has been developed to address the specific and unique needs of Pennsylvanian cheesemakers. Therefore, the purpose of this study is to improve the safety of farmstead cheese produced in Pennsylvania through a comprehensive food safety needs assessment, and based on the results, develop, deliver, and evaluate a customized educational intervention for cheesemakers in Pennsylvania. The comprehensive needs assessment was accomplished using 4 tools: 1) a survey for Pennsylvania Department of Agriculture (PDA) dairy inspectors; 2) a survey for Pennsylvania farmstead cheesemakers; 3) observations during cheesemaking sessions; and 4) microbiological sampling and analysis of environmental samples from Pennsylvania dairy farm's cheesemaking rooms. An overall comparison and compilation of results from each aspect identified key risk factors and gaps in basic sanitation and food safety. Interestingly, dairy processors indicated that their self-assessed knowledge, attitude, and behavior were "good" or "very good" in the areas of sanitation and food safety. The observations indicated that these processors may lack basic food safety practices and demonstrated gaps in their food safety knowledge, attitudes, and behaviors. As such, there appears to be a need for food safety training, with an emphasis on sanitation, for this underserved audience. Based on those results, a customized, counter-top food safety and sanitation training program was developed, disseminated, and evaluated for farmstead cheesemakers. Using a pre- and post-test knowledge, attitude, behavior, and skill assessment, it was determined that the training program produced significant increases in knowledge and positive changes in the handwashing skill among participants, but no significant changes in attitude and behavior were observed. An environmental microbiological assessment of cheesemaking rooms, with samplings before and after the training, revealed few significant changes in the microbial load, but some overall improvements were observed. This study demonstrated that a comprehensive needs assessment identified gaps in food safety and sanitation, leading to the development of a customized face-to-face training program, which was proven to be effective for improving the food safety and sanitation knowledge and handwashing skills of cheesemakers in Pennsylvania. Future use of this training program in other states could serve to further support and sustain the current local food movement in the U.S., while ensuring public safety and the success of individual farmers.

Perturbation of Rapid Eye Movement (REM) Sleep for Seizure Control in Rodent Model of Temporal Lobe Epilepsy

Parkar, Anjum The Pennsylvania State University ProQuest Dissert 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Seizures are detrimental to the quality of life. Approximately, 1-2% of the US population suffers from epileptic disorders characterized by spontaneous recurrent seizures. Of these, 25% are uncontrolled by pharmacological treatments. For such patients, alternative therapeutic approaches rely on using stimulation of certain brain regions that can assist in seizure control. Currently used open loop stimulation techniques, such as vagal nerve stimulation (VNS) and deep brain stimulation (DBS) have been tested in rodents and humans with some success. Continuous stimulation at regular intervals, such as VNS and DBS can lead to cognitive impairment, brain tissue damage as well as seizure induced epileptogenesis. Hence predicting and preventing seizures seems to be a more favorable approach. Decades of studies have shown that sleep or state of vigilance (SOV) can have an effect on seizures. It has been demonstrated that there is a strong correlation between rapid eye movement (REM) sleep and seizure occurrence. It's also been shown that besides REM state, theta (4-8Hz) associated withWake state is also epileptic. We use the chronic tetanus toxin (TeTx) rodent model of Temporal Lobe Epilepsy (TLE) to investigate if REM state can be perturbed through sensory stimulation of the Trigeminal Ganglion to control seizures. Our results indicate that REM state can be perturbed to control seizures. Fraction of seizures emerging out of stimulated REM state are far lower than REMs that were not stimulated. Since REM state was perturbed and not interrupted, we led to the conclusion that some other dynamic that co-occurs with REM state, makes REM state seizure permissive. Our results also indicated that upon stimulation of the animal during Wake state, when high theta is present, the fraction of seizures emerging from stimulated wake state are also lower compared to unstimulated Wake state. Hence, stimulation of Wake state during high theta, can also assist in seizure control. Taking these findings together, from a clinical standpoint, this novel approach of closed-loop stimulation based on SOV detection, can be used to design neuro-modulatory systems to help design better treatment approaches for patients refractory to AEDs for seizure control.

Evaluating the Implementation of and Farmers’ Participation in the Environmental Quality Incentives Program: A Case of Pennsylvania

Assan, Elsie The Pennsylvania State University ProQuest Dissert 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The negative environmental impacts of intensive agricultural production activities across the globe and specifically in the United States (US) is well known. Governments in affected countries including the US have instituted agri-environmental programs to address the negative environmental impacts of agriculture. At the US federal level, a suite of conservation programs referred to as Farm Bill conservation programs (e.g., Environmental Quality Incentives Program (EQIP)) provide technical and financial assistance to farmers and other rural land managers in exchange for their voluntary adoption of best management practices (BMPs) to address resources concern resulting from agriculture. The planning, policy development, and implementation of these programs encourage partnerships among government-sponsored conservation agencies and other public-private conservation agencies as well as public participation at the federal, state, and local levels of decision-making.Partnerships and public participation in conservation program planning and implementation processes are encouraged since it helps to account for public concerns, increase understanding of resource concern priorities, increase acceptance of the resultant program, and improve the efficient use of program resources and achievement of program goals. However, there is limited research conducted to explore the extent of public participation in program planning and implementation as well as how farmers make decisions to either participate or not participate in these government-sponsored agri-environmental programs. Drawing on the environmental governance framework and the diffusion of innovation theory, this dissertation sought to evaluate the implementation of and farmers’ participation in the Environmental Quality Incentives Program in Pennsylvania.This dissertation is built around three essays. The first essay utilizes data from interviews with conservation managers at federal, state, and local levels and program document analysis to explore the extent to which EQIP planning and implementation processes follow four concepts of environmental governance: adaptiveness, flexibility, and learning; knowledge co-production; acknowledgment of new actors and their roles; and accountability and legitimacy, at the federal, state, and local levels. The findings of the study show the presence of certain components of the four concepts in program planning and implementation processes, mainly because program decision-making processes and implementation practices are informed by congressional mandates and legislation. There is the participation of diverse stakeholders and conservation agencies in program processes at all three levels of decision-making and stakeholders play diverse roles in enhancing the achievement of program objectives. The essay also discusses the challenges identified and recommends strategies to enhance the governance of EQIP.The second essay reports the findings from interviews with conservation field staff at the local level regarding their perspectives on diverse stakeholder participation in EQIP planning and implementation practices at the local level, approaches and challenges to outreach, and barriers to EQIP implementation at the local level. The findings revealed a mixed perspective on the participation of diverse stakeholders in program processes. Further, the results showed that mostly government conservation agencies, their partners, and stakeholders work together and sometimes separately to conduct program outreach utilizing a variety of communication channels and delivery methods. The key outreach approach relied on by both government and non-government agencies is “word of mouth” to disseminate program information. The study findings indicate that farmer-related challenges (e.g., costs associated with program participation, anti-government sentiments, bureaucracy, and inadequate awareness about program existence and goals) and program-related challenges (e.g., staff capacity, attitude, and knowledge about agriculture, inadequate funding, bureaucracy, inflexible program rules, regulations, and internal policies, etc.) could hinder program implementation at the local level.The final essay utilizes both qualitative and quantitative data collected from three Pennsylvania counties within the Chesapeake Bay watershed to explore how farmers make decisions to participate in the Environmental Quality Incentives Program. It specifically examined farmers' familiarity with the program and perception of program fit to local farm management practices, farmers' sources of conservation program information, motivators of and barriers to program participation. The findings suggest that both EQIP participants and non-participants have differing levels of familiarity with the program and perceived the program as a good fit for addressing resources concern on the farm and off the farm. Further, EQIP participants and non-participants access program information from multiple sources including formal and informal sources. The findings also revealed program-related characteristics (e.g., cost share, environmental benefits, etc.) and personal reasons (e.g., environmental stewardship, social recognition for conservation efforts, etc.) as motivators for program participation. Self-autonomy and distrust of government conservation agencies, inadequate information on EQIP goals and benefits, religious reasons, and perceived limited knowledge of the heterogeneity of farms among conservation staff were some of the barriers to program participation. The essay also discusses how understanding the differences between the two groups of farmers can help conservation professionals enhance the participation of farmers in conservation programs.Taken together, the three essays highlight program governance issues that could be improved to enhance public participation, support, and buy-in for conservation programs. Overall, this dissertation findings could improve understanding of how national-level decisions about natural resources conservation influence implementation decisions at the state and local level as well as farmer participation in EQIP. More generally the findings could enable states in the northeast region, particularly, Pennsylvania to secure conservation gains and enhance farmer participation in conservation programs such as EQIP over time.

Explainable Predictive Modeling and Causal Effect Estimation from Complex Time-Varying Data

Hsieh, Tsung-Yu The Pennsylvania State University ProQuest Dissert 2021 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Time-varying data are prevalent in a wide variety of real-world applications for example health care, environmental study, finance, motion capture among others. Time-varying data possess complex nature and pose unique challenges. For example, time-varying data observed in real-world applications almost always exhibit nonstationary characteristics that challenges ordinary time-series methods with stationary assumptions. In addition, one may only have access to irregularly sampled data which prohibits the models that assume regularly observed samples. On the other hand, as machine learning and data mining algorithms have begun make an impact on real-world applications, merely providing accurate prediction is no longer sufficient. There is a growing need for interpretations and explanations to how the machine learning models make predictions in order for end-users to fully trust and adopt these models. In this thesis, we explore time-varying data in various practical scenarios and aim at enhancing model explainability and understanding of the data.First, we study the problem of building explainable classifiers for multivariate time series data by means of joint variable and time interval selection. We introduce a modular framework, the LAXCAT model, consisting of a convolution-based feature extraction and a dual attention mechanism. The convolution-based feature extraction network produces variable-specific representation by considering local time interval context. The dual attention mechanisms, namely variable attention network and temporal attention network, work in concert to simultaneously select variable and time interval that are discriminative to the classification task. We present results of extensive experiments with several benchmark data sets that show that the proposed method outperforms the state-of-the-art baseline methods on multi-variate time series classification task. The results of our case studies demonstrate that the variables and time intervals identified by the proposed method make sense relative to available domain knowledge.Second, to obtain a better understanding of the input multivariate time series data, we study dynamic structure learning which aims at jointly discovering hidden state transitions and state-dependent inter-variable connectivity structures. To address the research problem, we introduce a novel state-regularized dynamic autoregressive model framework, the SrVARM model, featuring a state-regularized recurrent neural network and a dynamic autoregressive model. The state-regularized recurrent unit learns to discover the hidden state transition dynamics from the data while the autoregressive function learns to encode state-dependent inter-variable dependencies in directed acyclic graph structure. A smooth characterization of the acyclic constraint is exploited to train the model in an efficient and unified framework. We report results of extensive experiments with simulated data as well as a real-world benchmark that show that SrVARM outperforms state-of-the-art baselines in recovering the unobserved state transitions and discovering the state-dependent relationships among variables.Third, functional data analysis provides another promising perspective at dealing with time-vary data. However, the representation learning capability of neural network-based method have not been fully explored for functional data. We study unsupervised representation learning from functional data and introduce the functional autoencoder network which generalizes the standard autoencoder network to the functional data setting. The functional autoencoder copes with functional data input by leveraging functional weights and inner product for real-valued functions. We derive from first principles.

Exotic emergent phenomena in the fractional quantum Hall effect

Coimbatore Balram, Ajit The Pennsylvania State University ProQuest Dissert 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

When two-dimensional electron systems are subjected to a perpendicular magnetic field, they exhibit the marvelous phenomenon known as the fractional quantum Hall effect (FQHE). This arises as a result of the formation of composite fermions (CFs), which are bound states of electrons and an even number of vortices. The FQHE of electrons is understood as arising from the integer QHE (IQHE) of CFs. Alongside superconductivity, Bose-Einstein condensation and spin-liquids, the CF quantum fluid provides a model system for understanding strongly correlated systems and their collective behavior. Although it has been more than three decades since the experimental discovery of FQHE, the field continues to produce profound insights and pose interesting problems some of which have been addressed in this thesis. A major unanswered question in the field of FQHE is the mechanism of FQHE for the 1/3 state in the second Landau level (7/3 state). Numerical studies of this state have brought out the following puzzle: exact diagonalization studies suggest that the ground state and excitations of 1/3 state in the second Landau level are different from its counterpart in the lowest Landau level (LLL), while entanglement spectra of the two states point to the fact that they fall in the same universality class. Using methods from CF theory we show that the excitations of the 7/3 FQHE lie in the same universality class as those of the 1/3 state but are strongly modified due to screening by CF excitons, thereby settling the above discrepancy. Armed with the exciton calculation, we illustrate that by imposing certain exclusion rules for CF excitons one can build the full spectrum of FQHE in the lowest Landau level. Equipped with the techniques to calculate the spectra of FQHE systems, we carry out an extensive study of FQHE of multi-component CFs (systems possessing degrees of freedom for eg: valley and spin degeneracy), which is applicable to FQHE in systems such as graphene, AlAs and GaAs quantum wells. We provide a comprehensive list of the possible fractions, their ground state energies and the critical "Zeeman" energies for the "spin" transitions between the states and compare them with the experimental observations. In the lowest Landau level of graphene, we find an excellent agreement between theory and experiments. However, in the second Landau level of graphene we find an unexpected spontaneous spin polarization of CFs. We predict that there are no spin transitions to be expected in the second Landau level of graphene, a result that could be tested out in experiments. We reanalyzed some old experimental data showing excitation modes below the Zeeman energy in the vicinity of 1/3 filling of the lowest Landau level whose theoretical origin was unexplained. Using methods of exact diagonalization and CF theory we demonstrate that these modes arise as a result of formation of trions of CFs which have sub-Zeeman energy due to skyrmion-like physics. In the past couple of years, the Fermi wave vector of CFs has been measured very accurately in pioneering experiments at Princeton University. Motivated by these experiments we address the issue of the validity of Luttinger's theorem (which is a fundamental tenet of Landau Fermi liquid theory) for the Fermi sea of CFs. Our calculations suggest that the CF Fermi sea may violate Luttinger's theorem slightly. This not only provides a nontrivial example of a non-Fermi liquid, but gives new insight into the nature of the CF Fermi sea state and opens a new line of inquiry in the field of FQHE.

A New Deal for Historic Preservation: The Impact of Relief Funding on the Cultural Landscape of Pennsylvania, 1932-1941

Calamia, Lynne M The Pennsylvania State University ProQuest Dissert 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

As one of only a handful of states to have a government agency responsible for historic matters, Pennsylvania was well-positioned to benefit from funding made available through New Deal relief programs. New Deal labor and funding played a pivotal role during the formative years of the field of historic preservation, but its impact is often overlooked on both a regional and national level. Through analysis of the records of the Pennsylvania Historical Commission, this dissertation explores the significance of historic preservation undertaken using New Deal relief funds and its relationship to the national urge to celebrate, remember, and commemorate history. Recent scholarship has identified that historic sites are shaped by the ideals of the groups that rallied to preserve and interpret them. This study identifies how the Pennsylvania Historical Commission affected the development of the state's cultural landscape using New Deal relief funds. Moreover, it explores the ways in which a legacy of political influence remains imprinted on state historical landmarks. The effect New Deal funding had on heritage management systems in Pennsylvania can offer broad insights into the formation of the character of the cultural landscape of the United States and the development of the field of historic preservation. This research expands on previous findings and contributes additional evidence that the history of historic preservation needs to be revisited in order to reveal fully the political and cultural dynamics of preservation and commemoration.

Colloidal Thermal Fluids

Lotzadeh, Saba The Pennsylvania State University ProQuest Dissert 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

In this dissertation, a reversible system with a well controlled degree of particle aggregation was developed. By surface modification of colloidal silica with aminosilanes, interactions among the particles were tuned in a controlled way to produce stable sized clusters at different pH values ranges from well-disposed to a colloidal gel. N-[3-(trimethoxysilyl)propyl]ethylenediamine (TMPE) monolayer on particle surface not only removes all the reactive sites to prevent chemical aggregation, also provides steric stabilization in the absence of any repulsion. After surface modification, electrokinetic behavior of silica particles were changed to that of amino groups, positive in acidic pH and neutral at basic pH values. By tuning the pH, the balance between electrostatic repulsion and hydrophobic interactions was reversibly controlled. As a result, clusters with different sizes were developed. The effect of clustering on the thermal conductivity of colloidal dispersions was quantified using silane-treated silica, a system engineered to exhibit reversible clustering under well-controlled conditions. Thermal conductivity of this system was measured by transient hot wire, the standard method of thermal conductivity measurements in liquids. We show that the thermal conductivity increases monotonically with cluster size and spans the entire range between the two limits of Maxwell's theory. The results, corroborated by numerical simulation, demonstrate that large increases of the thermal conductivity of colloidal dispersions are possible, yet fully within the predictions of classical theory. Numerical calculations were performed to evaluate the importance of structural properties of particles/aggregates on thermal conduction in colloidal particles. Thermal conductivity of non-spherical particles including hollow particles, cubic particles and rods was studied using a Monte Carlo algorithm. We show that anisotropic shapes, increase conductivity above that of isotropic particles where Maxwell's theory is reliable. This method also provides an accurate tool for evaluation of conductivity in colloidal suspensions between Maxwell's limits where theory is inadequate and experiments are limited due to colloidal difficulties. The effect of cluster configuration and degree of aggregation was investigated and showed that clusters of about the same size, but with different structures increases conductivity by different degree. We also showed that even small structural details such as the size of the neck that particles form during aggregation, can change the enhancement significantly. Colloidal clusters conduct heat more efficiently compared to fully dispersed particles at the same volume fraction. We present a predictive model to calculate the thermal conductivity of clusters by extending Maxwell's theory to non-spherical particles. We treat the clusters as spheres with effective thermal conductivity kc and volume fraction &phis;c. We calculate conductivity of the cluster from the upper bound of Maxwell's theory, and the conductivity of a dispersion of such clusters from the lower limit of the theory. We show that structural effects can be represented by a single parameter and a method was provided to obtain this parameter from numerical simulations. We test the theory against simulations as well as dispersions of colloidal cluster and find it to be in very good agreement with both. The results suggest that the variability of literature data and the unusually high values of thermal conductivity that have been reported in the literature can be fully accounted by the presence of clusters. (Abstract shortened by ProQuest.).

Active Interrogation of Fresh Nuclear Fuel in Shipping Containers

Sarnoski, Sarah E The Pennsylvania State University ProQuest Dissert 2019 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The International Atomic Energy Agency (IAEA) monitors States' adherence to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) through the application of nuclear safeguards. With a system of inspections and verification, nuclear safeguards ensures that nuclear material is being used for peaceful purposes. The current IAEA method for measuring fresh nuclear fuel requires the removal of the fuel assembly from its shipping container prior to either passive gamma-ray or active neutron measurements. Neither of these measurement techniques can be employed while the fuel assembly is in its shipping container.In this dissertation, a novel technique to measure fresh fuel in a shipping container was investigated. This active nondestructive assay technique interrogates the fuel with neutrons and induces fission in the fuel, thus creating subsequent fission products. These fission products decay and release gamma rays with energies higher than the passive gamma rays that the IAEA currently uses to measure fresh fuel assemblies. The high-energy gamma rays from fission products can escape the shipping container and be measured by a High Purity Germanium (HPGe) detector.The resultant measured gamma-ray spectrum can provide spectroscopic detail about the entire fuel assembly. The nondestructive interrogation technique was tested by designing an experiment to interrogate bare fresh fuel. The experiment interrogated a Low Enriched Uranium (LEU), Depleted Uranium (DU), and a challenge assembly comprised of an unknown combination of LEU and DU fuel rods. A total of 17 unique fission product gamma rays were identified in the LEU fuel. Simulations of the fission product ingrowth and decay confirmed the observation of these fission products. The gamma-ray spectrum was simulated in Monte Carlo N-Particle (MNCP) to predict the measured spectrum. The MCNP model proved to be a useful tool to benchmark the predictive capability of simulating measurement data and established confidence in the full shipping container simulation.Ratios of each fission product peak area were calculated for each fuel type and used in a Χ2 statistical analysis. The analysis proved that the LEU and DU fuel types were statistically different. Furthermore, with a reduced dataset of the measured fission products gamma rays, the Χ2 test proved that the challenge assembly was statistically different from both the LEU and DU assemblies. The results from the statistical analysis demonstrated that the active nondestructive assay technique can be used to differentiate between enrichment and identify missing LEU fuel rods. The composition of the challenge fuel assembly was determined using the activity of measured fission products and the known number of fuel rods. It was estimated to be 37 ± 7 DU rods and 71 ± 7 LEU rods, and the true composition was 40 DU rods and 68 LEU rods. Different configurations were analyzed to investigate the configuration of the LEU and DU rods in the challenge assembly. Simulations and a least squares analysis postulated the assembly was configured with replacement DU rods in the center of the assembly, which was revealed to be the true configuration.The fresh fuel was simulated inside a shipping container in MCNP. Simulations demonstrated fission product gamma rays contributed to the measured spectrum and were distinguishable above background signatures. This dissertation proved the active nondestructive assay of fresh fuel through a shipping container can be performed by neutron interrogation and measurement of gamma rays from induced short-lived fission products. This technique can be implemented by the IAEA to measure fresh fuel in a shipping container.

The Zinc Transporter ZNT2 (SLC30A2) as a Regulator of the Lactation Cycle: Implications in Suboptimal Lactation

Rivera, Olivia C The Pennsylvania State University ProQuest Dissert 2019 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The benefits of breastmilk on infant and maternal health are well understood. Although breastfeeding initiation rates are high (~84% of infants in the United States), the percentage of women that exclusively breastfeed for the recommended 6 months period of time remains below 30%. Concern regarding poor milk production is among the top reasons for early infant weaning. Moreover, the prevalence of women who fail to lactate despite supportive intervention may be as high as 15%. Collectively, this suggests that biological factors play a greater role in poor lactation performance than currently recognized.To perform the highly coordinated and energetically demanding task of milk production and secretion, the mammary gland must undergo proper development and maturation. Following embyronic and postnatal development, the gland enters a cyclic pattern of development that repeats with each pregnancy. This cycle of lactation is characterized by expansion and proliferation of the gland during pregnancy, further morphological maturation and molecular coordination of milk production and secretion during lactation, and extensive cell death and tissue remodelling during involution, returning the gland to the pre-pregnancy state. Dysregulation of any stage along the lactation cycle can negatively impact milk production.The zinc transporter ZnT2 (SLC30A2) is critical for progression through the lactation cycle. ZnT2-mediated zinc transport is required for appropriate development of the mammary gland during puberty, establishment of polarity in mammary epithelial cells and expansion of the secretory system during lactation, and activation of programmed cell death in response to involution signals. Several polymorphisms in SLC30A2/ZnT2 have been identified in breastfeeding women, many of which compromise or augment ZnT2 function, suggesting that defects in ZnT2 function may play a role in poor lactation performance. Here we used genetic, physiologic, and epidemiologic approaches to assess the role of ZnT2 in lactation performance. We hypothesized that ZnT2-mediated regulation of lysosome function drives progression of the gland from a lactating to an involuting state. We further hypothesized that mutations in혻SLC30A2/ZnT2 alter lysosome function thereby impairing mammary epithelial cell function during lactation, resulting in suboptimal lactation.In study 1, we showed that ZnT2 is required for lysosome biogenesis and activity and is a key driver of mammary gland involution. Using ZnT2-null mice, we determined involution is delayed in the absence of ZnT2. Furthermore, we showed that ZnT2 interacts with the proton pump vesicular-ATPase (v-ATPase), and is required for assembly of v-ATPase on the lysosome membrane and acidification of the lysosome. This demonstrated that ZnT2 is required for the inititation of mammary epithelial cell death during involution, thereby regulating cessation of lactation.In study 2, we determined the impact of a mutation in SLC30A2/ZnT2 on milk volume. We found a common SLC30A2 mutation, substituting threonine for serine at amino acid residue 288 (S288), was found in women with low milk volume. Studies in vitro showed, S288 promoted ZnT2 phosphporylation and upregulated lysosome biogenesis and acidification. Furthermore, the mutation drives ZnT2 localization to the lysosome and lysosomal zinc accumulation, but interestingly, did not activate cell death. Instead, expression of S288 was associated with a reduction in cellular ATP. These findings suggest women harboring the S288 mutation may have defects in mammary epithelial cell energy metabolism, which may lead to reduced milk volume.Collectively, my dissertation addresses the influence of normal and dysregulated ZnT2 function on key mammary eptihelial cell properties that define breast function during the lactation cycle. Although numerous mutations and genetic variants in SLC30A2/ZnT2 have been identified in humans, our research provides the only direct evidence they cause mammary epithelial cell dysfunction in the context of lactation. Importantly, our findings demonstrate that genetic variation in SLC30A2/ZnT2 is a biological factor contributing to low milk supply, thereby providing a barrier to continued lactation success. Furthermore, my dissertation provides the first evidence of a genetic component that contributes to performance of the mammary gland during lactation in humans. Ultimately, these findings may aid in the development of screening methods or interventions to address lactation complications, thereby improving maternal and infant health.