The impact of letter spacing on reading: a test of the bigram coding hypothesis

Identifying letters and their relative positions is the basis of reading in literate adults. The Local Combinations Detector model hypothesizes that this ability results from the general organization of the visual system, whereby object encoding proceeds through a hierarchy of neural detectors that, in the case of reading, would be tuned to letters, bigrams, or other letter combinations. Given the increase of receptive fields by a factor of 2 to 3 from one neural level to the next, detectors should integrate information only for letters separated by at most 2 other characters. We test this prediction by measuring the impact of letter spacing on reading, purifying this effect from confounding variables. We establish that performance deteriorates non-linearly whenever letters are separated by at least 2 blank spaces, with the concomitant emergence of a word length effect. We then show that this cannot be reduced to an effect of physical size nor of visual eccentricity. Finally, we demonstrate that the threshold of about 2 spaces is constant across variations in font size. Those results support the hypothesis that the fast recognition of combinations of nearby letters plays a central role in the coding of words, such that interfering with this representation prevents the parallel analysis of letter strings.

Consent to advanced imaging in antenatal pulmonary embolism diagnostics: Prevalence, outcomes of nonconsent and opportunities to mitigate delayed diagnosis risk

BACKGROUND

Nonconsent to pulmonary vascular (or advanced) imaging for suspected pulmonary embolism (PE) in pregnancy can delay diagnosis and treatment, increasing risk of adverse outcomes. We sought to understand factors associated with consent and understand outcomes after nonconsent.

METHODS

This retrospective cohort study was undertaken across 21 community hospitals from October 1, 2021, through March 31, 2023. We included gravid patients undergoing diagnostics for suspected PE who were recommended advanced imaging. The primary outcome was verbal consent to advanced imaging. Diagnostic settings were nonobstetric (99% emergency departments [EDs]) and obstetrics (labor and delivery and outpatient clinics). Using quasi-Poisson regression, we calculated adjusted relative risks (aRRs) of consenting with 95% confidence intervals (CIs). We also reported symptom resolution and delayed imaging at follow-up and 90-day PE outcomes.

RESULTS

Imaging was recommended for 405 outpatients: median age was 30.5 years; 50% were in the third trimester. Evaluation was more common in nonobstetric (83%) than obstetric settings (17%). Overall, 314 (78%) agreed to imaging and 91 (22%) declined imaging. Consenting was more prevalent in obstetric settings compared with nonobstetric settings: 99% versus 73% (p < 0.001). When adjusted for demographic and clinical variables, including pretest probability, only obstetric setting was independently associated with consenting: aRR 1.26 (95% CI 1.09-1.44). Seventy-nine (87%) patients declining imaging had 30-day follow-up. Eight of 12 who reported persistent or worsening symptoms on follow-up were again recommended advanced imaging and consented. Imaging was negative. None who initially declined imaging were diagnosed with PE or died within 90 days.

CONCLUSIONS

One in five gravid patients suspected of PE declined advanced imaging, more commonly in nonobstetric (principally ED) settings than obstetric settings. Patients symptomatic on follow-up responded favorably to subsequent imaging recommendations without 90-day outcomes. Improving the communication and documentation of informed consent and securing close follow-up for nonconsenters may mitigate risks of missed and delayed PE diagnosis.

Optimization of Intercropping Modes in Placodon grandiflorus

Intercropping enhances plant growth, increases yield, and boosts the accumulation of secondary metabolites. Platycodon grandiflorus (P. grandiflorus), a traditional Chinese medicinal herb, has limited research available regarding its intercropping practices. We aimed to (1) examine the changes in the physiological and biochemical indicators of plant growth during the intercropping process of P. grandiflorus, (2) assess the quality of P. grandiflorus when intercropped with different crops, and (3) evaluate the optimal intercropping mode for P. grandiflorus. This study utilized the two-year seedlings of P. grandiflorus as the test material in a field study. The intercropping treatments included P. grandiflorus monoculture (JG-JG), intercropping with Achyranthes bidentata (JG-NX), Saposhnikovia divaricata (JG-FF), Adenophora stricta (JG-SS), Zea mays (JG-YM), Setaria italica (JG-GZ), and Glycine max (JG-DD). We investigated the effects of these different intercropping modes on the growth, physiological and biochemical indicators, and the accumulation of five saponins in P. grandiflorus at various growth and development stages. Compared with JG-JG, the chlorophyll and the MDA contents significantly increased and decreased, respectively, in the JG-YM, JG-DD, and JG-NX treatments. All the three treatments enhanced the biomass and exhibited the higher levels of antioxidant enzyme activity and osmoregulatory substance content. JG-YM and JG-SS significantly (p < 0.05) improved the quality of P. grandiflorus, with JG-SS intercropping notably maintaining a high content of platycodin D. The results of this study provide a scientific basis for optimizing intercropping planting systems and advancing the sustainable development of the traditional Chinese medicine industry.

Long-term follow-up of resection of primary benign right ventricular tumours: a 10-year surgical experience

INTRODUCTION

Primary benign right ventricular tumours are rare. They can cause significant mortality without appropriate and timely treatment. We investigated surgical treatment and survival characteristics for right ventricular tumours.

MATERIALS AND METHODS

From 2007 to 2017, 21 patients with primary benign right ventricular tumours who underwent tumour resection were retrospectively reviewed. Clinical findings and follow-up results were analysed.

RESULTS

Thirteen men and eight women were enrolled, with a mean age of 42.3 ± 15.3 years. The most frequent histotypes were myxoma, haemangioma and papillary fibroelastoma. Eight patients underwent concomitant tricuspid valvuloplasty and one had tricuspid valve replacement. No major adverse events or death occurred during the perioperative period. One patient with haemangioma underwent partial tumour resection; however, the tumour regressed gradually during follow-up. Within the 10-year follow-up period (mean 4.8 ± 2.6 years), the recurrence-free and overall survival rates were 81.0% and 85.7%, respectively.

CONCLUSIONS

Tumour resection for primary benign right ventricular tumours is safe and effective, and has a good prognosis. Tricuspid valvuloplasty or tricuspid valve replacement may be necessary for the resection of right ventricular tumours to improve the haemodynamics. Haemangiomas naturally undergo spontaneous regression.