Camouflage pattern features interact with movement speed to determine human target detectability.

Applied ergonomics research examines not only the fit, form and function of military uniforms, but also their ability to effectively camouflage personnel as they perform job-related tasks. Many of these job-related tasks involve moving through environments, but existing literature examining camouflage effectiveness often assumes that movement effectively "breaks" even the best camouflage patterns, rendering them of limited utility for reducing the visual signature of a moving target. However, recent research demonstrates that animals equipped with adaptive camouflage change their patterning in predictable ways during movement and this adaptation decreases detectability, suggesting that uniform patterning may still hold value for reducing conspicuity during movement. The present experiment examined whether three visual pattern characteristics, local contrast, orientation, and spatial frequency, would influence the detectability of a moving human target. Participants attempted to detect and localize a simulated human target moving across a background scene, and a factorial design varied target movement speed, and the local contrast, spatial frequency, and orientation of its camouflage patterning. Results showed that target detectability was strongly influenced by target movement rate, pattern local contrast, and pattern spatial frequency, and these effects persisted even under conditions of very fast movement. Importantly, we found that the effect of local contrast was most robust under conditions of movement, suggesting its importance for reducing detectability of moving personnel. We conclude that movement is not always sufficient to break the concealment offered by a pattern with low contrast and a spatial frequency match with its background. Results are discussed in the context of visual processing theories and the application of these findings to the design and development of static and adaptive camouflage patterns for military personnel.

Obesity and hospital outcomes following traumatic injury: Associations in 9 years of patient data from a single metropolitan area.

Traumatic injury is a leading cause of death and disability worldwide. Obesity may put trauma patients at risk for complications leading to negative clinical outcomes. Data on all hospital admissions due to traumatic injury in the Detroit metropolitan area between 2006 and 2014 were obtained from the Michigan State Inpatient Database. Generalized linear modelling was used to compare patients with and without obesity on three outcomes: mortality, length of hospital stay and total charges for care. Adjusting for demographics, patients with obesity had 26% longer hospitalization. Adjusting for demographics and length of stay, charges were 8% higher. Obesity was unrelated to mortality. Obesity had greater impact on length of stay among younger adults; its relationship with charges emerged only among older adults. Obesity has significant clinical implications for trauma care. Demands for trauma care resources, and the charges associated with providing care, are likely to increase as obesity rates rise.

Visual salience and biological motion interact to determine camouflaged target detectability.

Target visual salience and biological motion independently influence the accuracy and latency of observer detection. However, it is currently unknown how these target parameters might interact in modulating the detectability of camouflaged human targets. In two experiments, observers performed a visual target detection task. In a pilot experiment, observers detected a static human target with parametrically varied visual salience, superimposed on a complex background scene. As expected, results demonstrated varied target detectability as a function of salience, with observers showing higher hit rates and faster response times as a function of increased salience. In the Main Experiment, observers detected simulated human targets walking across a complex scene at five different speeds and three different levels of visual salience (as validated in the pilot experiment). We found strong effects of both movement rate and visual salience, and the two parameters interacted. Specifically, increasing the rate of biological motion increased detectability for even the least salient camouflage patterns. In other words, biological motion can "break" even the least conspicuous camouflage pattern. In contrast, a very salient pattern was highly detectable under static and moving conditions. Results are considered in relation to theories of camouflage detectability, and trade-offs between camouflage development efforts versus advanced training in military maneuvering.

Masked priming for the comparative evaluation of camouflage conspicuity.

Human observer test and evaluation of camouflage patterns is critical for understanding relative pattern conspicuity against a range of background scenes. However, very few validated methodologies exist for this purpose, and those that do carry several limitations. Five experiments examined whether masked priming with a dot probe could be used to reliably differentiate camouflage patterns. In each experiment, participants were primed with a camouflaged target appearing on the left or right of the screen, and then made a speeded response to a dot probe appearing on the same (congruent) or different (incongruent) side. Across experiments we parametrically varied prime duration between 35, 42, 49, 56, and 63 ms. Results demonstrated that as prime duration increased, a response time disadvantage for incongruent trials emerged with certain camouflage patterns. Interestingly, the most conspicuous patterns showed behavioral differences at a relatively brief (49 ms) prime duration, whereas behavioral differences were only found at longer prime durations for less conspicuous patterns; this overall results pattern matched that predicted by a visual salience model. Together, we demonstrate the viability of masked priming for the test and evaluation of camouflage patterns, and correlated outcomes for saliency models and primed object processing.

Pressure Ulcers in the United States' Inpatient Population From 2008 to 2012: Results of a Retrospective Nationwide Study.

Pressure ulcers are common, increase patient morbidity and mortality, and costly for patients, their families, and the health care system. A retrospective study was conducted to evaluate the impact of pressure ulcers on short-term outcomes in United States inpatient populations and to identify patient characteristics associated with having 1 or more pressure ulcers. The US Nationwide Inpatient Sample (NIS) database was analyzed using the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9 CM) diagnosis codes as the screening tool for all inpatient pressure ulcers recorded from 2008 to 2012. Patient demographics and comorbid conditions, as identified by ICD-9 code, were extracted, along with primary outcomes of length of stay (LOS), total hospital charge (TC), inhospital mortality, and discharge disposition. Continuous variables with normal distribution were expressed in terms of mean and standard deviation. Group comparisons were performed using t-test or ANOVA test. Continuous nonnormal distributed variables such as LOS and TC were expressed in terms of median, and nonparametric tests were used to compare the differences between groups. Categorical data were presented in terms of percentages of the number of cases within each group. Chi-squared tests were used to compare categorical data in different groups. For multivariate analysis, linear regressions (for continuous variable) and logistic regression (for categorical variables) were used to analyze the possible risk factors for the investigated outcomes of LOS, TC, inhospital mortality, and patient disposition. Coefficients were calculated with multivariate regression with all included patients versus patients with pressure ulcers alone. The 5-year average number of admitted patients with at least 1 pressure ulcer was determined to be 670 767 (average overall rate: 1.8%). Statistically significant differences between patients with and without pressure ulcers were observed for median LOS (7 days [mean 11.1 ± 15] compared to 3 days [mean 4.6 ± 6.8]) and median TC ($36 500 [mean $72 000 ± $122 900] compared to $17 200 [mean $32 200 ± $57 500]). The mortality rate in patients with a pressure ulcer was significantly higher than in patients without a pressure ulcer (9.1% versus 1.8%, OR = 5.08, CI: 5.03-5.1, P <0.001). Pressure ulcers were significantly more common in patients who were older or had malnutrition. The results of this study confirm the importance of prevention initiatives to help reduce the negative impact of pressure ulcers on patient outcomes and costs of care.

Trends in bariatric surgery from 2008 to 2012.

BACKGROUND: Obesity is a global epidemic that has been increasing in prevalence. The only treatment method for durable weight loss is bariatric surgery. The aim of this study was to observe trends in usage and outcomes of bariatric operations used in the United States from 2008 to 2012. METHODS: Analysis was performed on bariatric surgery admissions from 2008 to 2012 based off of the Nationwide Inpatient Sample database. Data were selected from using International Classification of Disease, 9th Revision codes correlating to bariatric procedures for the purpose of obesity. Annual estimates and trends were reviewed for patient demographics, procedure type, patient outcomes, and length of stay (LOS). RESULTS: A total of 598,756 bariatric procedures were examined. Laparoscopic gastric bypass was the most commonly used surgical method in 2008 (58.2%). A decreasing trend in its use, and the use of laparoscopic gastric banding (LGB), was equipoised with increasing use of laparoscopic sleeve gastrectomy (LSG). Use of LSG accounted for 8.2% of procedures in 2011 and 39.6% in 2012. LGB and LSG had the lowest rates of complications, in-hospital morbidity and mortality, and the shortest LOS whereas open bypass and duodenal switch had the highest rates of complications, in-hospital morbidity and mortality, and longest LOSs. Overall rates of venous thromboembolism increased from .08% in 2008 to .215% in 2012. Respiratory complications decreased from 6.1% to 3.9%. There were no observed trends in rates of renal complications, visceral injury, bleeding, and infections. In-hospital morbidity decreased, whereas mortality rates were stable at .1%. CONCLUSIONS: The utilization of bariatric procedures has reached a plateau in the United States. Changes in the composition of procedural types suggest that LSG has become a popular alternative to gastric bypass and LGB.