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A State-of-the-Evidence Review: Impacts of Youth Agricultural Education Programs on Global Poverty, Resilience, and Food Security Results
No full textHistorically underestimated, youth can catalyze change towards positive community development. In developing countries, there is tremendous potential to engage youth, not only as passive participants in programming or as a vulnerable population in need of services, but as potential innovators, early adopters, and effective change agents towards the adoption of innovations to improve family and community well-being. However, the body of evidence exploring how youth agricultural education programs impact the necessary global goals of food security, resilience, and nutrition has yet to be systematically evaluated, synthesized, and mapped. This study, the first systematic review of youth agricultural education programs in low- and middle-income countries, employs a mixed methods, theory-based approach to identify evidence of program outcomes and impact, mapping the current state of the evidence to the U.S. Global Food Security Strategy results framework.
With the aim of greater policy and programmatic relevance, this study employs mixed methods theory-based systematic review methodology. The findings provide evidence of how access to information, innovations, and social systems through well-planned, and locally adapted agricultural education can have significant positive influence on individual and family-level changes. However, rigorous evaluation of the outcome and impact-level results of investments in agricultural education is woefully inadequate, and the majority of evaluations of youth agricultural education programs neglect to address dynamics of gender and social inclusion in the evaluation design or reporting. Going beyond the descriptive quantitative systematic review results with the aim of greater policy and programmatic relevance, this paper discusses the results of the qualitative analysis of the 79 included studies, identifying enablers and barriers to positive program outcomes in agricultural education programs, to summarize the individual-level, program-level, and enabling environment factors influencing program outcomes. Ultimately, the paper presents an emerging conceptual framework for the design of youth agricultural education programs in low- and middle-income countries. The detailed results of this study provide insight to build on what we know (scale what is working), improve what we are currently doing (drawing from the lessons learned), and invest in improved evaluation and measurement, presenting recommendations for future programs, policy, and research
Genetic Ablation of PITPNC1 Impairs Proliferation and Tumor Growth in Murine Melanoma via Mitochondrial Dysregulation
No full textPhosphoinositides (PIPs), the phosphorylated derivatives of phosphoinositols (PtdIns) are critical for eukaryotic cellular signaling. Major dysregulation of PIP signaling pathways has catastrophic effects, as subtle changes can cause neurodegenerative diseases and cancer in mammals. In this context, studying phosphatidylinositol transfer proteins (PITPs) urges our interest. Recent studies have indicated an important role for PITPs in determining the biological outcomes of PIP signaling, via a novel mechanism in which they likely do not function as lipid carriers.
PITPNC1, a member of under-investigated mammalian phosphatidylinositol transfer proteins (PITPs), is overexpressed in several metastatic tumors, including breast, colon, pancreatic, and melanoma. The tumor suppressor micro-RNA miR-126 also identifies PITPNC1 as a crucial target, of disease relevance. However, to date, no studies have emphasized the role of PITPNC1 in a complete knockout and immunocompetent environment. This has left critical gaps in understanding the role of protein in the signaling and metabolism of cancer cells and addressing these issues remain our primary focus. Our research demonstrates that PITPNC1 knockout mice are born alive and do not display overt phenotypes. However, phenotypic characterization of PITPNC1-/- mouse reveals changes in body fat and non-shivering thermogenesis in the females. PITPNC1 is associated with reduced patient survivability in melanoma cancer and its expression correlates with metastatic progression in murine and human melanoma cells. To understand the role of PITPNC1 in the context of melanoma, we employed a syngeneic murine melanoma model in which B16 melanoma cells were introduced to immunocompetent mice by subcutaneous injection. We demonstrated that PITPNC1 overexpression promotes tumor growth and metastasis in melanoma tumors. In addition, CRISPR-Cas9 generated PITPNC1 knock-out melanoma cells inhibit melanoma cancer progression in vivo in both non-cell-autonomous and cell-autonomous manner. Next, our findings indicate that PITPNC1 deletion alters the lipidomic profile in B16F10 melanoma cancer with loss of PIP3 lipid and cholesterol esters and accumulation of acylcarnitine and triglycerides, suggesting compromised fatty acid oxidation, which potentially underlies mitochondrial dysregulation in the PITPNC1 null condition. Lastly, we demonstrated that PITPNC1 null cells have a defective mitochondrial function with increased mitochondrial fragmentation in B16F10 melanoma cells. In this study, we conclude that PITPNC1 overexpression promotes tumor metastasis while genetic ablation of PITPNC1 impairs tumor growth in murine melanoma via mitochondrial dysregulation
Fracture Strength of 3D Printed Resin Interim Fixed Partial Dentures Varying Connector Sizes
No full textThe aim of this in vitro study is to determine the minimum connector size for 3-unit FPD���s comparing two different types of 3D printed resin to zirconia. A mandibular typodont quadrant was prepared for first premolar and molar all ceramic crowns with 0.5mm chamfer margins and total 6-degree convergence angle. The model was scanned via intraoral scanner (3Shape, Trios 4) and uploaded into CAD software (Exocad). 3-unit FPD with various connector sizes 9mm^2, 12mm^2, and 16mm^2 were designed. 3D printed two resins (OnX and Dentca C&B) with SprintRay Pro55. After the prints are completed, the interim FPDs were removed from the build plate, cleaned, and cured using manufacturer recommendations. FPDs were printed at a 0 degree build angle with 100��m layer thickness. 15 samples were printed per test group (N=90). Control group comparison made with a milled 3Y-zirconia 9mm^2 group (n=15). Fracture load tested with Instron machine with vertical pressure applied through pontic site at 1mm/min. FPDs placed onto typodont abutments and mounted on Instron machine. Failure was defined as the moment when the load dropped by 10% under the maximum value. The force (in Newtons) was recorded at the time of failure. Statistical analysis was completed using SPSS software to analyze the differences between the groups. Results were normally distributed, so one-way ANOVA was performed. Descriptive statistics will be added based on the location of fracture, and type of fracture. OnX had significantly higher maximum force at fracture (1236��135N) than Dentca C&B (884��136N, p<.001) and zirconia (456��87N; p<.001). Connector size had a significant difference for OnX for all sizes (p<.001), while significance for Dentca was only between 9 mm^2 and 16mm^2 (p=.006). The resins shattered upon failure, whereas zirconia simply split. Connector size and material type played significant roles in fracture resistance, with both resins withstanding significantly more force than typically generated during chewing
On the Security of End-to-End Encrypted Messaging and Calling Applications
No full textIn recent years, the use of end-to-end encrypted messaging and calling applications has risen, driven by the need for secure communications. While these applications protect against unauthorized access, concerns about potential vulnerabilities have emerged. End-to-end encryption (E2EE) aims to safeguard private communications, yet fears of eavesdropping and communication manipulation linger, especially from government entities or attackers. Despite its effectiveness, E2EE integrity can be compromised, like through key substitution attacks. Worries center on authentication ceremonies and potential user errors leading to man-in-the-middle (MitM) attacks. Additionally, the introduction of client-side scanning (CSS) in secure applications to detect harmful content raises privacy concerns. CSS���s local processing or endpoint filtering could undermine the promised encryption guarantees.
In this dissertation, we delve into the complexities surrounding the use of end-to-end encrypted messaging and calling applications, addressing issues of impersonations, MitM attacks, authenti-cation ceremonies, and the topic of CSS technology. Our work provides a systematic analysis of E2EE functionality and authentication ceremonies in popular applications. We propose an auto-mated approach to enhance and streamline the authentication ceremony within encrypted applications. Our work highlights vulnerabilities in voice-based authentication and stresses the need for stronger security measures. Additionally, we investigate the risks of using social media networks in the authentication ceremony and examine potential threats related to CSS technologies and their impact on E2EE principles.
Our dissertation provides the following contributions: First, we conduct a comprehensive security analysis of existing studies, identifying flaws and vulnerabilities in widely used encrypted applications, particularly focusing on authentication ceremonies. Second, we explore automated methods to enhance the authentication ceremony and reduce reliance on user interaction. Third, we undertake simulated investigations to identify potential vulnerabilities arising from exclusive reliance on a voice channel for the authentication ceremony in a real-world end-to-end encrypted application. This could compromise the security of static media and textual communications. The insights from our study suggest enhancing the security of end-to-end encrypted apps by using phonetically distinct words for codes, implementing warnings for suspicious voice code usage, employing multiple authentication channels, and prioritizing ongoing research for stronger security measures. Fourth, we introduce a novel investigation targeting social media authentication ceremonies, illustrating potential risks associated with user impersonation through counterfeit ac-counts. Our study suggests enhancing social media authentication security by displaying comprehensive user details, promoting hands-on user verification, using visual cues for unique identifiers, advocating continuous monitoring and adaptation, and fortifying end-to-end encrypted applications with multi-channel authentication. Lastly, we introduce an encrypted keyboard to address concerns related to CSS technology
Essays on Belief Updating and Decision-Making
No full textMy dissertation consists of three chapters on belief updating and decision-making.
The first chapter, coauthored with Marco Castillo, aims to understand how to mitigate negative economic consequences that can arise when individuals have biased beliefs about their surroundings. Specifically, we design two task assignment rules in teams based on a theoretical framework of Heidhues et al. (2018), and investigate their causal impact on task allocative efficiency. Using a series of laboratory experiments, we find that equally biased beliefs about team members��� productivities can lead to different efficiency outcomes depending on task assignment rules. The study highlights the importance of institutional designs that ensure economically desirable outcomes even in the presence of biased beliefs.
The second chapter, coauthored with Andy Cao, Marco Castillo, and Ragan Petrie, examines how non-pecuniary costs incurred during college impact college major choices. We conduct a randomized controlled trial to provide truthful information on major-specific teaching quality and inclusive climate to college freshmen and sophomores at Texas A&M University. We find significant effects of teaching and climate information, especially for choosing among business and economics majors. We also find that information has affected the college major choices of women more than it has for men. Our study shows that non-pecuniary aspects of human capital accumulation experienced during college can have an impact on the allocation of talent across fields.
The third chapter, co-authored with Hyundam Je, presents novel evidence that the timing of informativeness affects the level of motivated reasoning. Building upon the primacy effect, our framework predicts that receiving a signal before learning about its informativeness can exacerbate the extent of motivated reasoning compared to receiving it afterward. Our online experiment finds supporting evidence for this prediction. When participants learn about informativeness after receiving a signal, there is a stronger tendency for them to interpret the signal in a way that reinforces their preferred beliefs. These findings suggest the practical importance of structuring information as a strategy to mitigate motivated reasoning in information transmission
Experimental Demonstration of Multiport Multifrequency Power Systems
No full textWith considerable improvement on renewable energy and energy storage has been made, the use of renewable power sources and energy storage devices in the power system and the electrification of transportation are becoming a growing trend in recent years. To meet this need, increasing numbers of power electronics converters are included in these systems, which makes these systems become power electronics rich. In these power electronics rich systems, the interaction among the converters is significantly complicated and thus makes the power flow management challenging. The integration of these power electronics converters could be an appropriate solution to simplify the power flow management and enhance the controllability of the system.
In this research, a novel multiport multi-frequency power transfer system is presented. In this system, several independent virtual power flow channels could be established by introducing different switching frequencies in the power electronics converters. Virtual power isolation among the power flow channels could be built up because of orthogonality of the waveform. Hence, the virtual power flow channels in different frequencies will not interfere with each other. Bidirectional Power flow could happen between each port of the system, and they won���t interfere with each other.
In this research, a prototype multiport multi-frequency circuit based on the proposed theory is built up in the lab. Simulations and experiments with several scenarios are conducted. The basic operation of the prototype circuit is analyzed. And the performance of the simulations and experiments will be investigated and discussed. The feasibility of the multiport multi-frequency power transfer is validated by both simulations and experiments
Spinal Plasticity: Using Spinal Learning to Inform Maladaptive and Adaptive Effects of Nociceptive Input After Spinal Cord Injury
No full textThe traditional dogma of the spinal cord as a rigid conduit of information has been challenged in recent years. Evidence demonstrates that circuitry within the spinal cord can undergo adaptive and maladaptive plasticity particularly after spinal cord injury. Our work has focused on instrumental learning in the spinal cord along with the impact of nociceptive input after spinal cord injury. In this dissertation I explored how spinal cord injury affects plasticity. This work places particular emphasis on the impact of nociceptive input and factors that allow peripheral input to drive adaptive rather than maladaptive plasticity.
This dissertation explored spinal plasticity after injury in a complete thoracic (T2) transection in order to clarify the properties of the spinal cord itself. The first series of experiments show that the consequences of training vary with duration. These experiments also revealed two unexpected findings that motivated the following two chapters.
The second series identified a previously unknown effect of exposure to controllable
stimulation. An extended exposure to controllable stimulation altered how later stimulation is
interpreted, causing it to be read as adaptive (controllable) regardless of how it was presented.
This series also identified the anatomical locus of this shift and began to clarify its mechanistic
underpinnings.
The next series of experiments clarified the impact of proprioceptive signaling on the effects of uncontrollable noxious input. These experiments found that limb position modulates how nociceptive stimulation affects spinal cord plasticity. This series revealed that noxious stimulation only impairs plastic potential when applied while the hind limbs are extended.
The final set of experiments explored the role of ionic plasticity in spinal plasticity after injury. These experiments focused on the importance of the release of the GABAergic break on adaptive plasticity. They also identified pharmacological manipulations that can be used to manipulate ionic plasticity and, as a result, spinal plasticity. This suggests the potential of harnessing ionic plasticity to drive adaptive over maladaptive change.
Collectively, these experiments highlight the potential of harnessing plasticity after spinal cord injury for good. The studies show how the consequences of nociceptive stimulation vary with duration, order of presentation, limb position, and changes in GABA-dependent inhibition
Framework for Interactive, Individualized Feedback Design to Improve Thinking Skills in Construction Education
No full textOrganizational improvement relies heavily on having a competent workforce. To facilitate continuous improvement in the construction industry, this study examined the weaknesses in problem-solving skills among today's students (the future workforce). Based on these findings, a new educational approach was proposed, taking today���s student characteristics such as Acquired Attention Deficit Disorder (AADD) into consideration. This proposed educational approach was proved to have immediate and lasting effects beyond class periods on students��� learning through improved thinking skill exercises.
Initial investigations focused on identifying weaknesses in exercising adequate thinking skills in problem-solving and determining the cause beyond the weaknesses. Weaknesses were identified when faced with information processing, locating inputs from multiple sources, repeating the same cognitive processes over extended periods, unfamiliar calculation direction, and ignoring industry common sense due to a calculation-oriented mindset. The lack of fundamentals was identified as the primary cause of the weakness.
To resolve the weaknesses by addressing the cause behind the weaknesses, a new educational approach was proposed and validated through a mixed method. First, a feedback framework was designed which functions for knowledge delivery. Feedback was designed to deliver highly relevant knowledge to the problem at hand and to be presented in a size to allow easy information consumption in real-time considering the target students��� characteristics and learning preferences, Generation Z.
Feedback, a knowledge delivery tool, had immediate effects on exercising thinking skills in problem-solving on a sample of 13 graduate-level students in the Department of Construction Science at Texas A&M University who volunteered for the experiment and the following interview. Especially, two factors of feedback were counted as the key to improving thinking skills, and they are the feedback that was given immediately in real-time when it was in need (when in need) and the feedback that matched the target knowledge in question (what is needed).
The design feedback also had a lasting impact on exercising adequate thinking skills, by which improved academic achievement was demonstrated in a sample of 24 students enrolled in a construction estimating course for undergraduate students at Western Kentucky University. The result of the paired t-test evidenced the effectiveness of feedback on knowledge retention and academic achievement. Additionally, 71% of 24 study participants responded to the self-confidence survey, and the positive self-confidence in exercising thinking skills in each category in Bloom���s Taxonomy also denoted the efficacy of knowledge feeding in feedback.
This study theoretically expanded types of feedback by adding knowledge delivery to the existing feedback types. With this addition, feedback now functions not only giving confirmation or correction for the performance, but it also functions as a vehicle for knowledge delivery. Pragmatically, this study proposed a novel educational approach which aligns with today���s students��� learning preferences and weaknesses
Effects of Information on Markets and Behavioral Economics
No full textThe dissertation systematically analyzed the effect of information in various aspects of economic and social systems. Specifically, it focused on tax information on food markets, market information on strategic decisions, and social information on decision-making in economic games.
The first essay investigated the effects of sugar-sweetened beverages (SSBs) tax in the city of Berkeley and Philadelphia. We constructed a difference-in-difference (DID) model to examine the effects of the tax on the consumption and retail prices using Nielsen retail scanner data. The finding suggested that SSBs tax had no significant effect on consumption and prices in Berkeley, while the tax significantly increased the price and decreased the consumption of SSBs in Philadelphia. The opposite results in the city of Berkeley and Philadelphia suggested that geographical and social demographic characteristics would affect the effectiveness of a policy, and SSBs tax works better in large territories with diverse population.
The second essay analyzed transaction data from eBay to explore sellers��� strategies in online auctions. We focused on three selling formats on eBay: fixed-price listings, auctions, and BIN(Buy it Now)-auctions, comparing new products and outdated products for electronics. A probit model and Heckman correction procedure were applied to examine the effect of seller���s selling strategy on transaction success rate, final transaction price, and the seller���s revenue. Results indicate that fixed-price listings are preferred. Selling formats significantly influence outcomes for new products, while they show minimal effects for outdated ones. Moreover, we identify key price determinants for each listing format. The BIN price is crucial for fixed-price listings. For auctions and BIN-auctions, the duration and starting price emerge as key factors influencing transaction outcomes.
The third essay explores cooperation in social dilemmas, focusing on the impact of inequality on cooperation in public goods dilemmas. Our study evaluate cooperation in metrics of efficiency (total contribution) and equality (contribution from the wealthy). Incorporating 32 articles with 50 experiments, we found that heterogeneous endowments do not significantly affect equality, but it negatively impact efficiency, leading to decreased total contributions. Overall, heterogeneous endowments detrimentally affect cooperation. Furthermore, moderator analyses show that iteration numbers could negatively moderate the relationship between heterogeneous endowments and cooperation, indicating a greater detrimental effect on cooperation in public goods games with more iterations
Thermal Management and Defect Engineering in Reversible Transformations
No full textThis study delves into the nucleation behavior of thermoelastic martensitic transformations in Ni45Co5Mn36.7In13.3 microparticles, examining the influence of mesoscale order-disorder domains and phase boundaries between L21 and B2 phases on nucleation kinetics. The study compares microparticles with varying L21 domain interfacial area densities by employing solution heat treatment and secondary annealing. Characterization of 131 single particles reveals a range of undercooling from 11.3 to 59.4 K, with smaller volumes exhibiting the largest magnitude and variance. Surprisingly, nucleation site potency distributions between different domain sizes are statistically similar, suggesting that anti-site defects do not significantly impact nucleation at the length scales examined.
Additionally, our study explores the effects of helium and localized gallium irradiation on nucleation behavior. Helium irradiation induces Frenkel-pairs at our low doses (��� 0.1 dpa) and penetrates to about 4 ��m at 2 MeV. In comparison, localized gallium irradiation creates high-order defects (��� 140 dpa) and gallium implantation at depths of approximately 10 nm at 5 keV. Interestingly, helium irradiation and associated Frenkel-pairs do not statistically alter nucleation. In contrast, gallium irradiation leads to a notable reduction in the undercooling mean, indicating the potency of localized Ga+ irradiation to create potent nucleation sites.
Furthermore, this dissertation develops a theoretical framework based on thermal impedance to improve the melting efficiency of phase change material composites in transient power systems. The framework highlights the importance of the storage fraction in determining thermal impedance, offering insights into thermal design strategies for pulsed power systems. Finally, the study investigates the thermal impedance of PCM-intercalated copper foams with different pores per inch (40 ��� 90 PPI). Results show that at sufficiently small pores, the time for maximum thermal buffering decreased, peaking near on-times of 7.5 to 8 s, with diminishing returns observed for decreasing pore radii, independent of heat flux. However, the thickness of the foams was found to be a more prominent factor in reducing the observed timescales. This research contributes valuable insights into nucleation phenomena and thermal management strategies in materials science and engineering applications