Project description:IntroductionAlliaria petiolata, an herbaceous plant, has invaded woodlands in North America. Its ecology has been thoroughly studied, but an overlooked aspect of its biology is seed dispersal distances and mechanisms. We measured seed dispersal distances in the field and tested if epizoochory is a potential mechanism for long-distance seed dispersal.MethodsDispersal distances were measured by placing seed traps in a sector design around three seed point sources, which consisted of 15 second-year plants transplanted within a 0.25 m radius circle. Traps were placed at intervals ranging from 0.25-3.25 m from the point source. Traps remained in the field until a majority of seeds were dispersed. Eight probability density functions were fitted to seed trap counts via maximum likelihood. Epizoochory was tested as a potential seed dispersal mechanism for A. petiolata through a combination of field and laboratory experiments. To test if small mammals transport A. petiolata seeds in their fur, experimental blocks were placed around dense A. petiolata patches. Each block contained a mammal inclusion treatment (MIT) and control. The MIT consisted of a wood-frame (31 × 61× 31 cm) covered in wire mesh, except for the two 31 × 31 cm ends, placed over a germination tray filled with potting soil. A pan filled with bait was placed in the center of the tray. The control frame (11 × 31 × 61 cm) was placed over a germination tray and completely covered in wire mesh to exclude animal activity. Treatments were in the field for peak seed dispersal. In March, trays were moved to a greenhouse and A. petiolata seedlings were counted and then compared between treatments. To determine if A. petiolata seeds attach to raccoon (Procyon lotor) and white-tailed deer (Odocoileus virginianus) fur, wet and dry seeds were dropped onto wet and dry fur. Furs were rotated 180 degrees and the seeds that remained attached were counted. To measure seed retention, seeds were dropped on furs and rotated as before, then the furs were agitated for one hour. The seeds retained in the fur were counted.ResultsFor the seed dispersal experiment, the 2Dt function provided the best fit and was the most biologically meaningful. It predicted that seed density rapidly declined with distance from the point source. Mean dispersal distance was 0.52 m and 95% of seeds dispersed within 1.14 m. The epizoochory field experiment showed increased mammal activity and A. petiolata seedlings in germination trays of the MIT compared to control. Laboratory studies showed 3-26% of seeds were attached and retained by raccoon and deer fur. Retention significantly increased if either seed or fur were wet (57-98%).DiscussionWithout animal seed vectors, most seeds fall within a short distance of the seed source; however, long distance dispersal may be accomplished by epizoochory. Our data are consistent with A. petiolata's widespread distribution and development of dense clusters of the species in invaded areas.

Project description:BackgroundWastewater-based epidemiology (WBE) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be an important source of information for coronavirus disease 2019 (COVID-19) management during and after the pandemic. Currently, governments and transportation industries around the world are developing strategies to minimize SARS-CoV-2 transmission associated with resuming activity. This study investigated the possible use of SARS-CoV-2 RNA wastewater surveillance from airline and cruise ship sanitation systems and its potential use as a COVID-19 public health management tool.MethodsAircraft and cruise ship wastewater samples (n = 21) were tested for SARS-CoV-2 using two virus concentration methods, adsorption-extraction by electronegative membrane (n = 13) and ultrafiltration by Amicon (n = 8), and five assays using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and RT-droplet digital PCR (RT-ddPCR). Representative qPCR amplicons from positive samples were sequenced to confirm assay specificity.ResultsSARS-CoV-2 RNA was detected in samples from both aircraft and cruise ship wastewater; however concentrations were near the assay limit of detection. The analysis of multiple replicate samples and use of multiple RT-qPCR and/or RT-ddPCR assays increased detection sensitivity and minimized false-negative results. Representative qPCR amplicons were confirmed for the correct PCR product by sequencing. However, differences in sensitivity were observed among molecular assays and concentration methods.ConclusionsThe study indicates that surveillance of wastewater from large transport vessels with their own sanitation systems has potential as a complementary data source to prioritize clinical testing and contact tracing among disembarking passengers. Importantly, sampling methods and molecular assays must be further optimized to maximize detection sensitivity. The potential for false negatives by both wastewater testing and clinical swab testing suggests that the two strategies could be employed together to maximize the probability of detecting SARS-CoV-2 infections amongst passengers.

Project description:ImportanceObjectively measuring how Mohs defect reconstruction changes casual observer attention has important implications for patients and facial plastic surgeons.ObjectiveTo use eye-tracking technology to objectively measure the ability of Mohs facial defect reconstruction to normalize facial attention.Design, setting, and participantsThis observational outcomes study was conducted at an academic tertiary referral center from January to June 2016. An eye-tracking system was used to record how 82 casual observers directed attention to photographs of 32 patients with Mohs facial defects of varying sizes and locations before and after reconstruction as well as 16 control faces with no facial defects. Statistical analysis was performed from November 2018 to January 2019.Main outcomes and measuresFirst, the attentional distraction caused by facial defects was quantified in milliseconds of gaze time using eye tracking. Second, the eye-tracking data were analyzed using mixed-effects linear regression to assess the association of facial defect reconstruction with normalized facial attention.ResultsThe 82 casual observers (63 women and 19 men; mean [SD] age, 34 [12] years) viewed control faces in a similar and consistent fashion, with most attention (65%; 95% CI, 62%-69%) directed at the central triangle, which includes the eyes, nose, and mouth. The eyes were the most visually important feature, capturing a mean of 60% (95% CI, 57%-64%) of fixation time within the central triangle and 39% (95% CI, 36%-43%) of total observer attention. The presence of Mohs defects was associated with statistically significant alterations in this pattern of normal facial attention. The larger the defect and the more centrally a defect was located, the more attentional distraction was observed, as measured by increased attention on the defect and decreased attention on the eyes, ranging from 729 (95% CI, 526-931) milliseconds for small peripheral defects to 3693 (95% CI, 3490-3896) milliseconds for large central defects. Reconstructive surgery was associated with improved gaze deviations for all faces and with normalized attention directed to the eyes for all faces except for those with large central defects.Conclusions and relevanceMohs defects are associated with altered facial perception, diverting attention from valuable features such as the eyes. Reconstructive surgery was associated with normalized attentional distraction for many patients with cutaneous Mohs defects. These data are important to patients who want to know how reconstructive surgery could change the way people look at their face. The data also point to the possibility of outcomes prediction based on facial defect size and location before reconstruction. Eye tracking is a valuable research tool for outcomes assessment that lays the foundation for understanding how reconstructive surgery may change perception and normalize facial deformity.

Project description:Background and objectivesTechnology has the potential to provide assistance and enrichment to older people; however, the desired outcomes are dependent on users' acceptance and usage. The senior technology acceptance model (STAM) was developed as a multidimensional measure assessing older people's acceptance of general technology. It contained 11 constructs measured by 38 items and had shown satisfactory psychometric properties. However, the length of the questionnaire increased respondent burden and limited its utilization. The study aimed to develop a brief, reliable, and valid version of scale to measure older people's technology acceptance by shortening the full, 38-item STAM questionnaire.Research design and methodsThe research method included (1) a sequential item-reduction strategy maximizing internal consistency, (2) convergent and discriminant validity analysis based on confirmative factor analysis, and (3) an expert review of resultant items. Data previously collected for developing the original STAM questionnaire were used to create the brief version. The data were collected from 1,012 community-dwelling individuals aged 55 and older in Hong Kong. Internal consistency and construct validity of the shortened questionnaire were examined. Two experts were invited for reviewing content validity.ResultsThe final 14-item, brief version of the STAM questionnaire consisted of a 4-factor structure, representing classical technology acceptance constructs and age-related health characteristics. Theoretical relationships in the brief version showed similar patterns to the original STAM. The 14-item STAM demonstrated robustness in psychometrics by preserving the reliability and validity of the original STAM questionnaire.Discussion and implicationsThe availability of a reliable and valid assessment tool of the short STAM can help researchers and practitioners to measure older adults' acceptance of technology and its effective usage. The short STAM could save administration time, reduce the burden on respondents, and be included in large-scale surveys.

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Measuring cruise passenger dispersal through technology.

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Measuring cruise passenger dispersal through technology.

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