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Bi-criteria Scheduling in an Assembly Flow Shop with Limited Buffer Storage and Shift Production
Get PDFIn this research, the comparative performance of permutation and non-permutation schedules is investigated in an assembly flow shop (AFS) with shift production, where a limited buffer storage is available between two machines. Most of the traditional scheduling problems consider continuous production, i.e., production occurs for 24 hours (3 * 8-hour shifts) each day, seven days a week. However, some companies operate only one or two shifts each day, which creates a limited availability constraint on the machines. This causes a discontinuity in production between end and start of two successive production days. To mimic real-life industry practice, dynamic job release and dynamic machine availability times have been considered. Each job considered in a problem can have different weight assigned based on customers’ preferences. The setup times between jobs are assumed to be machine- and sequence-dependent. However, at the start of each production day, setup times are not sequence-dependent but depend on machine startup times such as preheating time, pressure build up, etc. The objective of the problem is to minimize the linear combination of total setup time and weighted tardiness. The minimization of total setup time represents producer’s interest whereas the minimization of weighted tardiness represents customers’ interest. Since these two objectives are not evaluated on a commensurate basis, a normalization factor is used.
The problem is formulated as a mixed-integer linear programming (MILP) model, MILP-1 for permutation schedules and MILP-2 for non-permutation schedules. The MILP models for small-size problem instances are solved to optimality using CPLEX. However, the problem is shown to be NP-hard. As a result, it is not possible to find an optimal solution within a reasonable time, as the problem size increases. Hence, a meta-heuristic search algorithm based on short-term Tabu Search (TS) and Tabu Search/Path-Relinking (TS/PR) are developed. TS represents a local search algorithm, whereas TS/PR represents a hybridization of local search enhanced with population-based search algorithm. Two algorithms each, are developed for both, permutation (PN) and non-permutation (NPN) sequences. One of the algorithms is based on short term TS and the other is based on TS/PR. The developed heuristics are tested on sixteen small-size problems and their solution quality are compared with the optimal solution obtained from CPLEX. The evaluations show that the developed heuristics obtain good quality solutions within much less computational time. For PN sequence, the best algorithm obtained an average deviation of 0.49% compared with the optimal solution and for NPN sequence, the deviation is 0.13%. In addition, a slight improvement of 2.68% was obtained by adopting an NPN sequence over PN sequence for these problem instances.
A statistical designed experiment is conducted to evaluate the difference in performance of the developed heuristics, and permutation and non-permutation schedules. The results show that the TS/PR algorithms outperform short-term TS, in the case of both PN and NPN sequences. The comparison between the solutions from the best PN algorithm and the best NPN algorithm shows that an average improvement of 1.64% is obtained by implementing an NPN sequence over PN sequence. The statistical analysis shows that the improvement offered by NPN sequence is statistically significant for problems with large number of product types and small number of jobs in each product. In addition, it is also shown that the NPN sequence performs better for non-continuous production as compared to continuous production. The efficiency of the algorithms was analyzed using the computational time required by the algorithms. The results show that PN algorithms require a significantly less computational time as compared to NPN algorithms. Hence, it is recommended that NPN sequences be considered only for the problems with large number of product types and small number of jobs in each product. For other problems, only PN sequence should be considered. TS/PR algorithm is recommended for both, PN and NPN sequences
Role of Cartilage and Bone Matrix Regulation in Early Equine Osteochondrosis
Get PDFOsteochondrosis (OC) results from disruption of the normal endochondral ossification process during articular cartilage and epiphyseal bone growth. Previous studies have revealed that cartilage canals are often associated with early OC lesions, especially along the ossification front. In early OC, extracellular matrix signaling pathways are expected to be altered, as they control matrix production and degradation associated with endochondral ossification. The aim of this study was to obtain a greater understanding of the role of cellular regulatory mechanisms in the pathogenesis of early equine osteochondrosis by identifying differences in gene and protein expression in both normal and diseased cartilage of adolescent horses. The objective of the study was to define the expression of chondrocyte signaling pathways in two specific regions, the osteochondral junction and in cells surrounding the cartilage canals. The hypothesis of this study was that when evaluating gene and protein expression of chondrocytes in diseased and normal early osteochondrosis samples, it was expected to find an upregulation of matrix metalloproteinases and a decrease in extracellular matrix gene expression within the osteochondral junction and cells surrounding the cartilage canals.
Samples were previously harvested from the femoropatellar joints of foals ranging in age from 1 to 6 months. Archived paraffin-embedded osteochondral samples (6 osteochondrosis affected, 8 normal controls) and cDNA from chondrocytes captured with laser capture microdissection (4 OC, 5 normal controls) were used in this project. Quantitative real-time PCR was then performed on pre-amplified samples, evaluating 18 target genes from extracellular matrix signaling pathways. The genes included Collagen types I, IIB, and X, Aggrecan, Aggrecanase-1, MMP-1, MMP-3, SOX 5, SOX 9, Jagged 2, COMP, Runx2, Gremlin 1, Ephrin B2, Lubricin (PRG4), Osteocalcin (BGLAP), bFGF, and TGF-ß3. Immunohistochemistry was performed on paraffin-embedded osteochondral samples for osteocalcin, Sox-9, and collagen type IIB using mouse monoclonal α-human antibodies and for lubricin using rabbit polyclonal α-human antibodies.
Downward trends were noted in gene expression of collagen type IIB, aggrecan, and SOX-9 in chondrocytes surrounding the cartilage canals of early osteochondrosis-affected samples compared to normal samples. In chondrocytes along the osteochondral junction, there was a trend of downregulation of lubricin and collagen type IIB in osteochondrosis samples compared to normal samples. No difference in osteocalcin, lubricin, collagen type II B, or SOX9 protein expression was apparent between OC and normal cartilage samples.
Osteochondrosis is a multifactorial developmental disorder with a complex system of closely regulated signaling pathways. Recent studies have explored the early pathogenesis of osteochondrosis, with particular focus on failure of vascular anastomoses at the cartilage canals, alterations in biomechanical forces around the cartilage canals, and regulation of extracellular matrix pathways. An aim of the current study is to extend this knowledge by evaluating expression of components of the extracellular matrix in both normal and osteochondrosis-affected adolescent osteochondral specimens. Results of the current study indicate that several matrix genes may be downregulated, including collagen type IIB, aggrecan, Sox-9, and lubricin in osteochondrosis.
Limitations of this study include a targeted rather than comprehensive evaluation of genes expressed in the extracellular matrix. In addition, only two cell populations were studied due to having a limited time to complete the laser capture procedure prior to sample degradation. It is also important to note that gene and protein expression studies do not address longitudinal changes or activity of molecules within the region. The results of this study contribute to the overall understanding of the pathogenesis of osteochondrosis and aid in identifying the role of cartilage and bone matrix regulation in early equine osteochondrosis
Response of Soil Microbial Activity and Community Composition to Timber Harvest in an Oregon Douglas-Fir Forest
Get PDFForests and forest soils are some of the largest biologically active carbon reservoirs in the world. Therefore, understanding how disturbances, such as forest harvest, influence biogeochemical cycling is particularly important for managing forests sustainably. Timber harvest can have large impacts on forest soils, which may affect the long-term productivity and function of forest ecosystems. Soil microbes are crucial regulators of biogeochemical cycling, and they can be impacted by disturbance of soil organic matter and compaction caused by logging. Despite their vital roles in ecosystem function, few studies have examined both microbial activity and community composition in response to forest harvest, and the link between microbial function and composition remains unclear. The goal of this thesis was to examine the impacts of different harvest intensities on microbial biogeochemical activity and community structure of prokaryotic and fungal communities in a Douglas-fir forest in Oregon. Samples were collected 3 months and 3 years post-harvest in order to determine the short-term impacts of forest harvest on the soil microbial community and to help elucidate the links between microbial function and structure in forest soils.
The first objective was to compare microbially mediated nutrient cycling among harvest treatments with different levels of organic matter removal and compaction through examination of extracellular enzyme profiles and carbon and nitrogen mineralization. Enzyme activities generally differed little among harvest treatments but varied more through time. The only significant differences in enzyme activities among treatments occurred 3 years post-harvest: the activities of β-glucosidase, cellobiohydrolase, and peroxidase were elevated in harvest treatments compared to the unharvested reference. Carbon and nitrogen mineralization were determined using soil microcosm incubations. Respiration (carbon mineralization) did not differ among treatments 3 months post-harvest and only small differences were observed among treatments 3 years post-harvest. By contrast, harvest treatments typically had greater nitrate and total mineralized N than the reference both 3 months and 3 years post-harvest. As a whole, changes in activity took longer than 3 months to manifest with some differentiation in activity between harvest treatments visible after 3 years. Furthermore, forest harvest appeared to be the main impact on activity rather than organic matter or soil compaction manipulations.
The second objective was to examine soil microbial communities and identify any alterations in diversity and structure of these communities as a result of different harvest intensities. Communities were examined by extracting DNA from soils and performing amplicon sequencing using Illumina Miseq. Timber harvesting with different levels of organic matter removal and soil compaction led to distinct differences in prokaryotic and fungal communities. Microbial composition and structure varied more between years and compared to the unharvested reference than among harvest treatments. Relative abundance of many bacterial phyla, including the dominant Proteobacteria, Acidobacteria, and Verrucomicrobia, was significantly altered among harvest treatments 3 years post-harvest but not immediately after harvest. Less abundant phyla such as Nitrospirae (bacterial) and Thaumarchaeota (archaeal) were also impacted by harvest. In the fungal communities of harvest treatments, Basidiomycota abundance decreased whereas Ascomycota abundance increased. The unharvested reference had significantly greater ectomycorrhizal fungi, and harvest treatments had an enrichment of saprotrophs.
Finally, alterations in microbial activity were compared with changes in community structure to help identify impacts of harvest on soil microbes that may affect nutrient cycling and long-term productivity. Enzyme activity was generally correlated with bacterial communities more than fungal. Increases in soil nitrate and total mineralized nitrogen were attributed to increased abundance of nitrogen cycling autotrophs, including Nitrospirae and Thaumarchaeota. Neither bacterial nor fungal communities were well correlated with alterations in carbon cycling parameters such as respiration and fast and slow-cycling carbon pool parameters. Overall, concurrent changes in activity and community structure imply that alteration in community structure did impact community function. Although clear links between activity and community composition were difficult to discern, our results suggest that some bacterial and fungal groups have the potential to be used as indicators of disturbance and ecosystem status, at least in the short-term
Changing Mother-Daughter Relationships in Isan Rural Culture in the Context of Women’s Migration
Get PDFThis thesis explores the changes in mother-daughter relations in Northeast Thailand over the last three generations in relation to migration out of this region. Qualitative interviews were done with ten families in two villages; the interviews focused on representatives of three generations of women in each family. In recent decades, in Northeast Thailand (also known as the Isan region) many people have left their hometowns because of economic hardship and agricultural instabilities to find economic opportunities. Rural people have become migrant laborers in Bangkok, regional areas, and overseas. In Northeast Thailand the kinship system is matrilineal and matrilocal, characterized by inheritance and care flowing particularly between mother and youngest daughter. Women are the core of the family system, playing an important role in the production activities of the household, trading, and religious rituals. Faced with modernity as they migrate, women change and force transformation in the family and rural villages. The thesis finds conditions of high debt, dependence on remittances, grandchild care by grandmothers, and diminishing landholdings. Although matrilineality continues, with the youngest generation, mother-daughter relationships have weakened in the areas of matrilocality and emotional closeness, but are maintained by remittances faithfully sent
A Decolonial Option for Literary Criticism
Get PDFThe ongoing “method war” in literary criticism that has manifested as the impasse between Critique and Postcritique, which are identified respectively with paranoid and reparative modes of reading, raises existential questions about criticism in the face of its declining social value under neoliberalism. This thesis enters that impasse to suggest a decolonial option for criticism that rewrites modes of reading and critiquing through knowledges that emerge from across the colonial difference, and specifically from indigenous perspectives. The trickster discourse and the aestheSic practice of beadwork, as laid out through the literary exempla of Leslie Marmon Silko’s Almanac of the Dead and Beth Piatote’s The Beadworkers, present decolonial models for criticism where the objective is to write against the domination of the modern/colonial world and posit alternative modes of and knowledges about being with/in the world. This thesis contends that the decolonial option not only bypasses the impasses of neoliberalism but also encourages the healing of colonized people from the colonial wound
Kinesiology’s Knowledge Production, Mass Translation, and Utilization Problem: Critical Appraisal and Theoretical Analysis of Physical Activity Websites
Get PDFThrough this dissertation, the quality of freely available physical activity promotion web articles that lay adults would likely locate online was critically appraised and theoretically analyzed. Three broad categories were considered. They were 1) message consistency with national health guidelines for physical activity; 2) suitability for health-related communication; and 3) use of evidence-based concepts from theories of health behavior. The results of this dissertation indicate that physical activity promotion web articles that communicate primarily through text have multiple qualities that enhance their message appeal and potential to be effective, largely irrespective of production source but not always the case. The results also suggest that the educational value of such web articles is undermined in two ways: 1) correctable suitability issues and 2) the use of messages inconsistent with national physical activity health guidelines. These issues which mitigated web article quality were general to web articles irrespective of production source. Though slow, knowledge translation of kinesiology is happening and the rate may vary depending on the quality indicator. Collaborations between scholars and organizations that produce freely available physical activity resources are needed. From them, safety nets can emerge that works towards two key aims. First, sensitize producers and developers to basic knowledge in kinesiology for achieving health and physical fitness through physical activity. Second, sensitize producers and developers to issues that detract from the educational quality of physical activity resources—then build capacity to address them. Towards these two aims, advice for helping to ensure the quality dissemination of physical activity resources were advanced within the Discussion section, as well as direction for future research aimed at closing the “science gap” in knowledge translation
Fishing for Hypoxia: Exploring Coastal Oxygen Dynamics and Predictability of Low Oxygen Episodes through a Partnership with the Oregon Dungeness Crab Fishing Fleet
Get PDFCoastal hypoxia, or low oxygen episodes pose a threat to marine resources in the Pacific Northwest. Previous research into nearshore oxygen dynamics have linked coastal upwelling to this seasonally occurring phenomenon, however the manifestation of hypoxic waters over coastal fishing grounds was not well understood. Through a partnership with Dungeness crab fishermen, this research documents the pilot use of an experimental dissolved oxygen (DO) sensing system designed to be used in tandem with fishing effort. Through an unprecedented network of coastal oxygen observations deployed throughout the Oregon coast, this partnership allowed researchers to explore the regional variations in DO during the 2020 upwelling season. In addition to better understanding spatial variation in nearshore ocean conditions, I also sought to create statistical models that could be used to generate predictions of hypoxic episodes. Outcomes generated by this research illustrate the value of adding additional DO observations to forecasts, and demonstrate the viability of the collaborative experimental system to supplement traditional ocean observing techniques
Anything You Can Do: The Effect of Observed Model Perseverance on Students' Persistence in an Unrelated Task
Get PDFTask persistence has been associated with task mastery in many different realms of learning, and is thought to be evoked particularly through the observation of positive models; however, the capability of such exposures to transfer across domains is not currently well-understood. The present study sought to examine the effect of observing a model persevere on the observer’s own task persistence and task enjoyment in both related and unrelated tasks. Participants (N = 30) first observed either a video of a model struggling with a puzzle and eventually solving it or no video. Participants then completed a similar or an unrelated challenging learning task, operationalized using either a hand puzzle like the one seen in the video (i.e., related) or a learning guide and evaluation designed to teach and evaluate learning of force calculation (i.e., unrelated). Participants reported their subjective enjoyment of the task and I measured time spent on the task. I expected results to demonstrate that exposure to modeled perseverance improves task persistence (measured as a function of time spent on a puzzle or a learning task) and increases subjective enjoyment, as predicted by Bandura’s social cognitive theory; however, results suggest that modeling has no significant impact on persistence times and is negatively associated with enjoyment. Self-efficacy alone was an effective predictor of persistence
The geology and geochemistry of the Sulphurets district porphyry Au-Cu-Mo deposits, British Columbia, Canada: Insights from a long-lived, gold-enriched porphyry district
Get PDFPorphyry Cu-(Au-Mo) deposits are critical sources of several economically important metals. The processes governing the total metal endowment and relative proportions of ore metals at these large magmatic-hydrothermal deposits remain uncertain. The Sulphurets porphyry district, in northwestern British Columbia, Canada, contains four porphyry Au-Cu-Mo deposits that each feature distinct Cu/Au and Cu/Mo ratios. From north to south, these deposits include the Iron Cap, Mitchell-Snowfield, Sulphurets, and Kerr porphyry deposits. Porphyry mineralization has been recognized in the Sulphurets district since the 1960s. However, extensive drilling campaigns during the last 15 years have significantly expanded the resources and limits of the known deposits. Today, the Sulphurets district represents one of the largest undeveloped gold resources in Canada (>2,300 t Au). This study presents new geochronology data for the district (Chapter 2) and an in-depth petrochemical and zircon geochemical study of porphyry intrusions across the district (Chapter 3). Together, these chapters provide fresh insights into the magmatic controls on the endowment of Au, Cu, and Mo in porphyry Cu-(Au-Mo) deposits. Chapter 4 features the first comprehensive shortwave infrared models of hydrothermal alteration for the Sulphurets district deposits and investigates the effects of post-mineral greenschist facies metamorphism and deformation on phyllosilicate mineralogy, composition, and spectral absorptions as well as base metal dispersal patterns in porphyry Cu-(Au-Mo) deposits.
The Sulphurets district porphyry Au-Cu-Mo deposits are found in the Stikinia terrane of northwestern British Columbia, Canada. The deposits were formed in the Early Jurassic, during a prolific period of arc magmatism in Stikinia. Six new Re-Os molybdenite ages and five new U-Pb zircon ages provide improved constraints on the timing and lifespan of magmatic-hydrothermal activity in the district. These data elucidate the age of mineralization at the Kerr (201.4 ± 0.9 Ma, 203.1 ± 0.9 Ma; Re-Os), Sulphurets (194.8 ± 0.9 Ma, 194.9 ± 0.9 Ma, 195.1 ± 0.9 Ma; Re-Os), and Iron Cap
(194.1 ± 0.9 Ma, 194.3 ± 0.8 Ma; Re-Os) deposits, complementing existing geochronology for mineralization at the Mitchell-Snowfield deposit (190.3 ± 0.8 Ma to 192.0 ± 1.0 Ma; Re-Os). The Re-Os molybdenite geochronology data reveal that the Sulphurets district is exceptionally long-lived, featuring one of the longest known lifespans among worldwide porphyry copper districts (11 ± 3.5 m.y.). U-Pb zircon geochronology for plutonic rocks in the district, including existing U-Pb ages as well as new U-Pb ages presented in Chapter 2, further supports a great time span of Early Jurassic magmatic-hydrothermal processes (189.9 ± 2.9 Ma to 203.7 ± 5.8 Ma). The determination of the chronology of deposit formation within the district reveals several compelling temporal trends. Notably, the Cu/Au and the Cu/Mo metal ratios of the Sulphurets district deposits decrease progressively from the oldest Kerr deposit (Cu/Au ≈ 18,600; Cu/Mo ≈ 850; based on Measured & Indicated resource models) to the youngest Mitchell-Snowfield deposit (Cu/Au ≈ 2,300; Cu/Mo ≈ 20). Furthermore, the volumetrically important syn-mineral plagioclase-hornblende diorite to monzodiorite porphyry intrusions (JDi) of the Texas Creek suite become incrementally more evolved in the district deposits over time, with the Kerr deposit featuring lower whole rock K2O and Ce/V values (average Ce/V = 0.06) relative to the other, younger deposits (Mitchell-Snowfield average Ce/V = 0.13). Additional evidence that the magmatic rocks from the oldest Kerr deposit were slightly more primitive and less alkaline than those from the younger district deposits comes from hydrothermal alteration assemblages, as Kerr features smaller amounts of hydrothermal K-feldspar and more hydrothermal chlorite. The temporal co-variation between decreasing Cu/Au and Cu/Mo ratios with increasingly evolved and K-enriched syn-mineral intrusions among the district deposits suggest an intimate association between magmatic composition and the potential for Au and Mo enrichment in porphyry Cu-(Au-Mo) deposits.
Additional insights into magma petrogenesis were obtained from zircon trace element geochemistry. Zircon samples from 11 ore-related Texas Creek suite intrusions were analyzed by SHRIMP-RG ion microprobe. Critical information gained from zircon geochemistry includes: 1) estimates of zircon formation temperatures from Ti-in-zircon geothermometry; 2) estimates of magmatic oxidation states from Eu anomalies; and 3) insights into magmatic evolution, fractionation, and mixing processes from variations in REE contents, chondrite-normalized REE patterns and parameters such as Th/U ratios. Decreases in Ti-in-zircon temperatures (~950 to 610°C) are accompanied by increases in EuN/EuN* values (~0.2 to 1.0) and decreases in Th/U ratios (~1.5 to 0.1). These shifts document the progressively increasing oxidation state and the shift to more evolved compositions of the parental melts for each deposit, during punctuated periods of cooling over the lifespan of the district. Additionally, zircon REE ratios, such as Yb/Gd, Yb/Nd, and Gd/Nd, track the incremental crystallization of hornblende ± clinopyroxene ± apatite ± titanite in the parental melts. Moreover, the large Au endowment of the district deposits is likely tied to the strongly oxidized nature of the Sulphurets district magmas (average zircon EuN/EuN* > 0.4). High oxidation states suppress the formation of magmatic sulfide melts, which strongly partition Au and, to a lesser extent, Cu, and if removed from the melt via settling or accumulation would reduce the potential for Au-Cu ore formation.
The Sulphurets district was subjected to greenschist facies metamorphism and penetrative cleavage development during the development of the mid-Cretaceous Skeena fold and thrust belt. This post-mineral modification is known to have resulted in widespread argon loss in phyllosilicates that is documented by Ar-Ar muscovite ages from across the Sulphurets district that were universally reset during the mid-Cretaceous (~110 ± 10 Ma). Additional impacts of greenschist metamorphism have not been thoroughly examined in porphyry Cu-(Au-Mo) deposits. However, hydrothermal alteration minerals that are unstable at greenschist temperatures (300 - 450°C), as well as sulfide species that are susceptible to remobilization at these temperatures, could be significantly affected by post-mineral metamorphism. Porphyry Cu-(Au-Mo) deposits typically display vertical and lateral zoning patterns of metals and hydrothermal mineralogy that can be documented by shortwave infrared (SWIR) absorption features, and both are widely used as prospecting and vectoring tools. SWIR absorption features in porphyry Cu-(Au-Mo) rock samples are primarily controlled by variations in the species and compositions of hydrothermal phyllosilicates, and the impact of metamorphism on SWIR reflectance spectra is uncertain. XRD analyses (N = 111) from this study confirm that the bulk of the white micas in the district formed at conditions consistent with lower greenschist metamorphism (>300°C; Kübler index values <0.27). Shortwave infrared measurements (N = 19,562) on drill core samples were analyzed, and numerical models for several absorption features were generated for the Kerr, Mitchell, and Iron Cap porphyry Au-Cu-Mo deposits. On the basis of comparison of these deposit SWIR models with published SWIR zoning studies in non-metamorphosed porphyry deposits, the SWIR zoning patterns appear to persist through, and potentially get enhanced by, greenschist facies metamorphism and extensive deformation. Spatial zoning of the 2200-nm absorption feature (~2190 – 2230 nm) from shorter to longer wavelengths reflects the transition from acidic to more neutral paleo-hydrothermal conditions, whereas zoning of the 2350-nm feature (~2330 – 2355 nm) coincides broadly with the zoning of Cu + Au grades at Kerr, Mitchell, and Iron Cap. In comparison to other deposits, the average position of the 2200-nm absorption feature in the Sulphurets district has been shifted towards higher wavelengths during metamorphism in feldspar-bearing rocks, reflecting post-mineral recrystallization of white micas in near-neutral to alkaline pH conditions, to more phengitic compositions around the deposit peripheries. Finally, the zoning patterns of base metals such as Pb and Zn display considerable scatter and have been remobilized in a set of post-mineral quartz + carbonate ± chlorite ± sphalerite ± galena ± chalcopyrite veins. In summary, our results suggest that SWIR and metal zoning patterns persist in the porphyry Au-Cu-Mo deposits of the Sulphurets district despite modification and partial resetting due to post-ore greenschist metamorphism and deformation, but that potential modifications must be carefully assessed during exploration activities
Implications of Person Perception Across Development: The Reciprocal Influences of Problem Behavior and Facial Trustworthiness
Get PDFPeople of all ages and ethnicities implicitly use others’ facial characteristics to evaluate their personalities. The field of person perception has identified several mechanisms through which one’s facial appearance may be associated with one’s behavior. For example, a person with an untrustworthy-looking face may elicit negative reactions from social partners, which may then cause the person to engage in more delinquency than they otherwise would have (expectancy effects), with negative outcomes for both the actor and those affected by their delinquent behavior. Alternatively, engagement in delinquency may cause a person to develop an untrustworthy appearance (a Dorian Gray effect). Such degradations in facial trustworthiness may in combination with expectancy effects interfere with desistence of delinquency during early adulthood or disadvantage persons who have desisted antisocial behavior. Thus, it is paramount to understand and interrupt both processes across development in order to reduce incidence of delinquency and encourage desistence. Yet the investigation of facial trustworthiness has rarely been generalized to a developmental context. The present project examined both the target of interpersonal perceptions (Study 1) and the processes that lead perceivers to behave differently toward those targets (Study 2). Study 1 leveraged methods from developmental psychology to follow a sample of 206 at risk boys from ages 13 to 38. This was the first study to chart the development of facial trustworthiness across adolescence and into adulthood. Initial levels of facial trustworthiness at age 13 predicted slower escalation in delinquency during adolescence and faster declines in delinquency during adulthood (expectancy effects), and initial levels of delinquency at age 13 predicted more rapid degradations in facial trustworthiness across adolescence (Dorian Gray effects). Study 2 utilized methods from experimental psychology to investigate the extent to which ambiguous behavioral information may intensify the effect of facial trustworthiness on perceivers’ evaluations, a process that may contribute to expectancy effects. However, Study 2 failed to replicate an effect of facial trustworthiness on perceivers’ evaluations of targets, thus, findings were equivocal regarding the primary hypothesis. It is the thesis of this project that 1) highlighting experiences of the perceiver and the target, and 2) utilizing methods from developmental and experimental psychology, are both necessary to understand the broader implications of person perception research