Human color constancy has been studied for over 100 years, and there is extensive experimental data for the case where a spatially diffuse light source illuminates a set of flat matte surfaces. In ...natural viewing, however, three-dimensional objects are viewed in three-dimensional scenes. Little is known about color constancy for three-dimensional objects. We used a forced-choice task to measure the achromatic chromaticity of matte disks, matte spheres, and glossy spheres. In all cases, the test stimuli were viewed in the context of stereoscopically viewed graphics simulations of three-dimensional scenes, and we varied the scene illuminant. We studied conditions both where all cues were consistent with the simulated illuminant change (consistent-cue conditions) and where local contrast was silenced as a cue (reduced-cue conditions). We computed constancy indices from the achromatic chromaticities. To first order, constancy was similar for the three test object types. There was, however, a reliable interaction between test object type and cue condition. In the consistent-cue conditions, constancy tended to be best for the matte disks, while in the reduced-cue conditions constancy was best for the spheres. The presence of this interaction presents an important challenge for theorists who seek to generalize models that account for constancy for flat tests to the more general case of three-dimensional objects.
The James Webb Space Telescope Mission Abney, Faith E; Anderson, Harry James; Anderson, Kristen ...
arXiv (Cornell University),
04/2023
Paper, Journal Article
Odprti dostop
Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope ...with an aperture of at least \(4m\). With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the \(6.5m\) James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.
Aedes aegypti (L.) (Diptera: Culicidae) is a highly invasive mosquito whose global distribution has fluctuated dramatically over the last 100 years. In Australia the distribution of Ae. aegypti once ...spanned the eastern seaboard, for 3,000 km north to south. However, during the 1900s this distribution markedly reduced and the mosquito disappeared from its southern range. Numerous hypotheses have been proffered for this retraction, however quantitative evidence of the mechanisms driving the disappearance are lacking. We examine historical records during the period when Ae. aegypti disappeared from Brisbane, the largest population centre in Queensland, Australia. In particular, we focus on the targeted management of Ae. aegypti by government authorities, that led to local elimination, something rarely observed in large cities. Numerous factors are likely to be responsible including the removal of larval habitat, especially domestic rainwater tanks, in combination with increased mosquito surveillance and regulatory enforcement. This account of historical events as they pertain to the elimination of Ae. aegypti from Brisbane, will inform assessments of the risks posed by recent human responses to climate change and the reintroduction of 300,000 rainwater tanks into the State over the past decade.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aedes aegypti is the primary vector of exotic arboviruses (dengue, chikungunya and Zika) in Australia. Once established across much of Australia, this mosquito species remains prevalent in central ...and northern Queensland. In 2011, Ae. aegypti was re-discovered in the town of Gin Gin, Queensland, by health authorities during routine larval surveillance. This town is situated on a major highway that provides a distribution pathway into the highly vulnerable and populous region of the state where the species was once common. Following the detection, larval habitat and adult control activities were conducted as a public health intervention to eliminate the Ae. aegypti population and reduce the risk of exotic disease transmission. Importantly, genetic analysis revealed a homogenous cluster and small effective population vulnerable to an elimination strategy. By 2015, adult surveillance revealed the population had expanded throughout the centre of the town. In response, a collaboration between research agencies and local stakeholders activated a second control program in 2016 that included extensive community engagement, enhanced entomologic surveillance and vector control activities including the targeting of key containers, such as unsealed rainwater tanks. Here we describe a model of the public health intervention which successfully reduced the Ae. aegypti population below detection thresholds, using source reduction, insecticides and novel, intensive genetic surveillance methods. This outcome has important implications for future elimination work in small towns in regions sub-optimal for Ae. aegypti presence and reinforces the longstanding benefits of a partnership model for public health-based interventions for invasive urban mosquito species.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Xenotransplantation clinical trials may begin soon. A persistent risk of xenotransplantation, known for decades, is the possibility that a xenozoonotic infection could be transferred from a xenograft ...to its recipient and then to other human contacts. Because of this risk, guidelines and commentators have advocated for xenograft recipients to agree to either long-term or lifelong surveillance mechanisms.
For the past few decades, one solution that has been proposed to ensure that xenograft recipients will comply with surveillance protocols is the use of a heavily modified Ulysses contract, which we review.
These contracts are most often used in psychiatry, and their application to xenotransplantation has been espoused several times with minimal criticism.
In this article, we argue against the applicability of Ulysses contracts in xenotransplantation based upon (1) the telos of the advance directive that may not be applicable to this clinical context, (2) the suspect nature of enforcing Ulysses contracts in xenotransplantation, and (3) the ethical and regulatory hurdles that such enforcement would require. Although our focus is on the US regulatory landscape in preparation for clinical trials, there are applications globally.
Xenotransplantation (XTx) presents a potential clinical alternative to the shortage of human organs for transplantation. Before clinical trials occur in the United States, public assessments are ...crucial to understand potential barriers to acceptance. The purpose of this study was to explore barriers and identify characteristics associated with attitudes toward XTx. A survey assessing demographic characteristics and attitudes toward XTx was distributed to a nationally representative sample of adults aged ≥18 years in the United States. Regression analysis was employed to identify characteristics associated with attitudes toward XTx. Between May 25 and June 14, 2023, 5008 respondents completed the survey. Importantly, half of the respondents expressed low or no knowledge of either transplantation or XTx. Approximately 40% expressed discomfort with receiving a pig organ for themselves or a loved one. Despite a lack of xenotransplant outcome data, 36% were open to experimental XTx if they needed a transplant. However, 57% rated lack of current evidence of success or fear of complications as top concerns. Regression models consistently associated being younger, female, not needing an organ, or being a member of a racial minority group with lower acceptance. This survey is the largest to date exploring public attitudes toward XTx. Despite overall acceptance, concerns persist. Increasing public acceptance is key as the field advances.
Salmonella is a major cause of enteric disease in Canada. Cases of salmonellosis were attributed to retail meats, food animal manure contact, and surface water sources using a microbial subtyping ...approach coupled with adjustments for exposure. Results indicated that 64.7% of cases were attributed to chicken breast meat, followed by frozen raw breaded chicken products (12.9%), ground chicken (9.1%), water (3.0%), pork chops and sausage (1.3%), ground beef and veal (0.7%), turkey parts (0.5%), and molluscs (0.0%). The salmonellosis incidence rate in the FoodNet Canada sentinel sites fell by one third with a parallel drop of one third in the percent of cases attributed to chicken breast meat between 2015 and 2019. Decreases in the contribution of many of the top serovars to the percentage of cases attributed to chicken breast meat indicates some emerging success with broiler breeder chicken vaccination programs. In addition, preliminary prevalence results for frozen raw chicken products in late 2019 suggests the Canadian Food Inspection Agency intervention in 2019 requiring any Salmonella on these products to be below a detectable amount may be having an impact, though more data post intervention is needed to be more conclusive.
•Salmonellosis cases were attributed to foodborne, animal contact, water sources yearly to detect the impact of interventions.•Chicken meat was the most important source, with some yearly variations between specific chicken products.•Industry and government interventions having a positive impact in reducing salmonellosis cases and chicken-related serovars.
Background
We performed an analysis of the National Cancer Database (NCDB) to evaluate overall survival (OS) in patients with base of tongue (BOT) cancer treated with external beam radiation therapy ...(EBRT) combined with brachytherapy (BT).
Methods
The tongue NCDB Participant User File was used to obtain demographic and clinical patient data. The Kaplan–Meier method was used to determine OS. Significance was determined using univariable and multivariable Cox proportional hazards models.
Results
At 3 years, OS was 69.6%, 77.1%, and 63.7% for patients treated with EBRT (n = 27 954), EBRT + BT (n = 209), or BT alone (n = 154), respectively (P = .01). On multivariable analysis, the instantaneous hazard of death for patients receiving EBRT + BT was 25% (Hazard ratio HR = 0.75, 95% CI: 0.58‐0.98) lower than patients receiving only EBRT (P = .03).
Conclusions
The addition of BT to EBRT in BOT cancer has an OS benefit.
Using Greener Gels To Explore Rheology Garrett, Brendan; Matharu, Avtar S; Hurst, Glenn A
Journal of chemical education,
04/2017, Letnik:
94, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A laboratory experiment was developed to investigate the rheological properties of a green calcium-cross-linked alginate gel as an alternative to the traditional borax-cross-linked poly(vinyl ...alcohol) gel. As borax is suspected of damaging fertility and the unborn child, a safe, green alternative is necessary. The rheological properties of a sodium alginate solution were examined as a function of temperature using capillary viscometry. Gelation and degelation processes were followed using rotational viscometry. The non-Newtonian shear-thinning properties were also exemplified by determining the viscosity as a function of spindle speed using the rotational viscometer. Students making the transition from a first- to second-year undergraduate chemistry program within a natural sciences degree have successfully conducted this laboratory experiment.
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