Radiological Diagnosis?

A 5-month-old female Collie dog was examined for intermittent gagging and labored respiration of 7 days duration. Physical examination showed good general body condition. Ausculation of the thorax revealed loud heart sounds on the right side and weak heart sounds on the left side. Lung sounds were normal on the right side but on the left side normal lung sounds were absent and intestinal sounds were heard

Misreading the Hybrid Face: The Alienation of Performed and Authentic Self in Danzy Senna’s Caucasia and Chang-Rae Lee’s Native Speaker

Race is epistemological. It shapes worldviews, conceptions of self, and interactions with society. It defines who belongs in the national community and who counts as fully human. The myth of whiteness as a homogenizing and nativist identity creates false personas around and within racialized others. These personas define non-white populations according to exclusionary stereotypes. These stereotypes, in turn, separate populations based on appearance and cultural practice. This thesis applies Critical Race Theory and comparative racialization tools to examine the historical implications of race on the conception of an authentic, or internally true, identity. These implications are illustrated by the dynamics of choice and racial identification for multi-racial and multi-cultural individuals in literature. By comparing African-American and Asian-American racialization in relation to the homogenizing white presence, this thesis explores the performance of race as social legibility in post-civil rights-era discourse

Aquatic food webs and heavy metal contamination in the upper Blackfoot River, Montana

Acid mine drainage (AMD), characterized by low pH and abundant heavy metals, is a widespread problem affecting water quality and fish habitat in Montana. Montana’s upper Blackfoot River exhibits impaired water quality from historic mining that has significantly degraded aquatic habitat and reduced fish and invertebrate abundance in impacted streams. The goal of this study is to investigate the direct and indirect effects of mine-related heavy metals contamination on aquatic ecosystems by examining changes in aquatic community composition, bioaccumulation, and toxicity risk of heavy metals along a contamination gradient in the upper Blackfoot River. Three primary research questions were addressed in this study: 1) How are macro-invertebrate communities influenced by heavy metals contamination? 2) What are the implications of changes in food web structure for exposure pathways? 3) What levels of environmental contamination produce the greatest risk to upper trophic levels? Invertebrate and fish communities impacted by heavy metals in the upper Blackfoot River were sampled in 2009 and 2010 for community composition analyses and metals concentrations. The results of this study indicate that an increase in heavy metals contamination in the upper Blackfoot River results in important changes in exposure pathways of metals entering aquatic food webs through invertebrate food sources, as well as exposure pathways of metals to fish. The greatest exposure risk to upper trophic levels from the pool of bioavailable metals in invertebrates occurred at moderately contaminated sites where moderate invertebrate abundance and moderate sediment metals levels coincided. In addition, the highest metals concentrations in fish tissue were at sites with high exposure values in invertebrates, rather than sites with the highest sediment contamination levels. The results of this study indicate that biological mechanisms influencing the movement of heavy metals in aquatic food webs are important factors for assessing toxicity risk to upper trophic levels that may not be evident when considering environmental contamination alone

Freeform Extrusion of High Solids Loading Ceramic Slurries, Part I: Extrusion Process Modeling

A novel solid freeform fabrication method has been developed for the manufacture of ceramic-based components in an environmentally friendly fashion. The method is based on the extrusion of ceramic slurries using water as the binding media. Aluminum oxide (Al2O3) is currently being used as the part material and solids loading as high as 60 vol. % has been achieved. This paper describes a manufacturing machine that has been developed for the extrusion of high solids loading ceramic slurries. A critical component of the machine is the deposition system, which consists of a syringe, a plunger, a ram actuated by a motor that forces the plunger down to extrude material, and a load cell to measure the extrusion force. An empirical, dynamic model of the ceramic extrusion process, where the input is the commanded ram velocity and the output is the extrusion force, is developed. Several experiments are conducted and empirical modeling techniques are utilized to construct the dynamic model. The results demonstrate that the ceramic extrusion process has a very slow dynamic response, as compared to other non-compressible fluids such as water. A substantial amount of variation exists in the ceramic extrusion process, most notably in the transient dynamics, and a constant ram velocity may either produce a relatively constant steady-state extrusion force or it may cause the extrusion force to steadily increase until the ram motor skips. The ceramic extrusion process is also subjected to significant disturbances such as air bubble release, which causes a dramatic decrease in the extrusion force, and nozzle clogging, which causes the extrusion force to slowly increase until the clog is released or the ram motor skips.Mechanical Engineerin

Freeform Extrusion of High Solids Loading Ceramic Slurries, Part II: Extrusion Process Control

Part I of this paper provided a detailed description of a novel fabrication machine for high solids loading ceramic slurry extrusion and presented an empirical model of the ceramic extrusion process, with ram velocity as the input and extrusion force as the output. A constant force is desirable in freeform extrusion processes as it correlates with a constant material deposition rate and, thus, good part quality. The experimental results in Part I demonstrated that a constant ram velocity will produce a transient extrusion force. In some instances the extrusion force increased until ram motor skipping occurred. Further, process disturbances, such as air bubble release and nozzle clogging that cause sudden changes in extrusion force, were often present. In this paper a feedback controller for the ceramic extrusion process is designed and experimentally implemented. The controller intelligently adjusts the ram motor velocity to maintain a constant extrusion force. Since there is tremendous variability in the extrusion process characteristics, an on-off controller is utilized in this paper. Comparisons are made between parts fabricated with and without the feedback control. It is demonstrated that the use of the feedback control reduces the effect of process disturbances (i.e., air bubble release and nozzle clogging) and dramatically improves part quality.Mechanical Engineerin

Genetic analysis of amyotrophic lateral sclerosis identifies contributing pathways and cell types

Despite the considerable progress in unraveling the genetic causes of amyotrophic lateral sclerosis (ALS), we do not fully understand the molecular mechanisms underlying the disease. We analyzed genome-wide data involving 78,500 individuals using a polygenic risk score approach to identify the biological pathways and cell types involved in ALS. This data-driven approach identified multiple aspects of the biology underlying the disease that resolved into broader themes, namely, neuron projection morphogenesis, membrane trafficking, and signal transduction mediated by ribonucleotides. We also found that genomic risk in ALS maps consistently to GABAergic interneurons and oligodendrocytes, as confirmed in human single-nucleus RNA-seq data. Using two-sample Mendelian randomization, we nominated six differentially expressed genes (ATG16L2, ACSL5, MAP1LC3A, MAPKAPK3, PLXNB2, and SCFD1) within the significant pathways as relevant to ALS. We conclude that the disparate genetic etiologies of this fatal neurological disease converge on a smaller number of final common pathways and cell types

Development of a scale to assess avoidance behavior due to a fear of falling: the fear of falling avoidance behavior questionnaire

Journal ArticleBackground. A history of falls or imbalance may lead to a fear of falling, which may lead to self-imposed avoidance of activity; this avoidance may stimulate a vicious cycle of deconditioning and subsequent falls. Objective. The purpose of this study was to develop a questionnaire that would quantify avoidance behavior due to a fear of falling. Design. This study consisted of 2 parts: questionnaire development and psychometric testing. Questionnaire development involved an expert panel and 39 residents of an assisted living facility. Sixty-three community-dwelling individuals with various health conditions participated in psychometric testing. Method. Questionnaire development included the evaluation of face and content validity and factor analysis of the initial questionnaire. The final result of questionnaire development was the Fear of Falling Avoidance Behavior Questionnaire (FFABQ). In order to determine its psychometric properties, reliability and construct validity were assessed through administration of the FFABQ to participants twice, 1 week apart, and comparison of the FFABQ with other questionnaires related to fear of falling, functional measures of balance and mobility, and daily activity levels using an activity monitor. Results. The FFABQ had good overall test-retest reliability (intraclass correlation coefficient=.812) and was found to differentiate between participants who were considered ?fallers? (ie, at least one fall in the previous year) and those who were considered ?nonfallers.? The FFABQ predicted time spent sitting or lying and endurance. Limitations. A relatively small number of people with a fear of falling were willing to participate. Conclusion. Results from this study offer evidence for the reliability and validity of the FFABQ and support the notion that the FFABQ measures avoidance behavior rather than balance confidence, self-efficacy, or fear