This study examines high-achieving students in Norwegian lower secondary schools who follow accelerated learning trajectories in mathematics, so-called fast-tracks. It asks whether and how fast-tracks improve high-achieving students' learning and performance. The analyses rely on high-quality administrative register data from Norway covering all students who graduated from 2010 to 2017. The results show that fast-track students outperform regular students in mathematics. They are overrepresented with top school grades, so effects are often underestimated using standard methods. To address ceiling effects in grades, we apply Tobit regression and a novel use of correlated-random effects (Mundlak model), embedding fixed-effects and instrumental-variable approaches within nonlinear Tobit models. The results suggest that (1) the fast-tracks improve the students' learning, and (2) the students are selected and self-selected, based on prior performance and background characteristics. When comparing teacher-set grades versus exam grades set by anonymous, randomly assigned examiners, the results suggest that (3) teachers give fast-track students even better grades than regular students. One plausible explanation is that teachers perceive or label fast-track students as more talented than other students. The findings, in particular, suggest that Norwegian teachers compensate disadvantaged fast-track students who originate from homes with limited parental educational resources.

Nociceptors, primary afferent nerve fibers that signal noxious stimuli, are broadly divided into slowly conducting unmyelinated C fibers and fast-conducting myelinated A fibers. Whereas C-nociceptors have been extensively studied, considerably less is known about the function of A-nociceptors. Here we demonstrate, combining genetic targeting of these fibers in mice with observations in human participants, a key involvement of A-nociceptors in mechanical nociceptive withdrawal reflexes and affective pain. In mice, optogenetic stimulation induced rapid and precise withdrawal reflexes as well as place aversion and facial expression changes consistent with pain affect, while inhibition strongly impaired mechanical nociceptive withdrawal reflexes. Prolonged A-nociceptor activation induced mechanical pain hypersensitivity and central sensitization. In a rare individual lacking thickly myelinated Aβ fibers, and in healthy participants during preferential Aβ-fiber nerve block, mechanical withdrawal reflexes were absent and mechanical pain perception reduced. Together, these findings identify fast-conducting mechano-nociceptors as essential drivers of nocifensive behaviors in mice and humans.

Hepatic actinomycosis is a rare infection caused by Actinomyces spp. It is characterized by nonspecific clinical presentation and imaging findings that may mimic hepatic neoplasms. We report the case of a 43-year-old man presenting with a three-month history of right upper quadrant pain and weight loss. Magnetic resonance imaging revealed an infiltrative hepatic mass involving segments IV, V, and VIII, suggestive of malignancy. Percutaneous biopsy was inconclusive; therefore, an extended right hepatectomy with segmental colectomy was performed. The definitive diagnosis was established by histopathological examination, which demonstrated sulfur granules and filamentous structures consistent with Actinomyces spp. The patient received prolonged antibiotic therapy, with favorable clinical evolution and no evidence of recurrence during follow-up. Hepatic actinomycosis is an entity with limited representation in the Latin American literature and should be considered in the differential diagnosis of atypical liver masses, even in the absence of predisposing factors. Its presentation may mimic hepatic malignancy and lead to unnecessary major surgical interventions. In clinical practice, it is essential to maintain a high index of suspicion for infectious etiologies, particularly when initial biopsies are inconclusive.

The hock bone proportions in young Polish Warmblood horses (69) were studied based on x-ray image measurements done during official breeding horse performance testing. Six measurements were used to identify 4 width and length proportion indices. The radiological examinations were done before and after horse training, which consists of work with or without the rider at walk, trot and canter (40-50min) with some light class (< 100cm) jumping (<12 jumps) 6 days a week. The training effect was investigated using analysis of variance (procedure MIXED, Statistical Analysis System). The statistical model included a random horse effect and fixed effects: training (1st, 2nd investigation), training centre (1st, 2nd), sex (19 stallions, 50 mares), limb (left, right), and regression on age in days. Proportion of the widest part of distal tibia to the widest part of proximal metatarsus (shortcut AM in the text; p<0.0001) and proportion of the length of the tarsus (proximal intertarsal to distal tarsometatarsal joint) to tibiotarsal and calcaneus length (shortcut DN; p=0.0288) were greater after training. Distal epiphysis of the tibia (A) seems greater after training than the proximal epiphysis of the 3rd metatarsal epiphysis (M). The width proportions revealed most strongly affected by training compared to the length proportions, the other proportions varied randomly. The correlations between the measured values changed over the course of the training in parallel with the overall values - ranging from -0.2 to 0.2. Repeatabilities of measured indices were mostly high (>0.7).

Cardiac involvement in rheumatoid arthritis (RA) is an uncommon but clinically relevant manifestation that may extend beyond pericardial and valvular disease to involve peri-annular and subvalvular fibrous structures. Aneurysmal and pseudoaneurysmal complications affecting the left ventricular outflow tract (LVOT), aortic root, and adjacent regions are exceptionally rare and largely described in isolated case reports. We performed a systematic review of the reported cases to characterize the clinical, imaging, pathological, and therapeutic features of RA-associated aneurysmal or pseudoaneurysmal cardiac involvement. The review identified a small number of reported cases in which RA-related inflammation involved peri-annular structures, often mimicking infective endocarditis and frequently associated with significant valvular dysfunction. Across cases, multilevel structural involvement, including the aortic root, LVOT, membranous interventricular septum, and cardiac valves, was common. High-grade atrioventricular conduction disturbances were observed in a substantial proportion of patients, reflecting the close anatomical relationship between inflammatory lesions and the cardiac conduction system. Multimodality imaging, combining transthoracic and transesophageal echocardiography with cardiac computed tomography, cardiac magnetic resonance, or FDG-PET/CT, was consistently required to define anatomical extent and guide management. Histopathological examination, when available, proved essential to exclude infection and demonstrated granulomatous inflammation or rheumatoid nodules in autoimmune-mediated cases. Most patients required surgical intervention due to advanced structural disease, while isolated inflammatory involvement without aneurysmal degeneration responded to immunosuppressive therapy. Outcomes were generally favorable. This review underscores that RA-related cardiac inflammation may predispose to aneurysmal degeneration of peri-annular fibrous structures, with complex presentations in which a complete diagnostic pathway, including multimodality imaging and pathological confirmation is critical.

Abdominal angiostrongyliasis (AA) is an emerging infection caused by the nematode Angiostrongylus costaricensis. Human infection occurs through ingestion of food contaminated with infective third-stage larvae (L3). Although endemic in Central and South America, AA remains underdiagnosed and underrecognized in clinical practice. We report the case of a female patient with a history of bariatric surgery, residing in southern Brazil, who presented with right lower quadrant abdominal pain and mild eosinophilia. Initial diagnostic hypotheses included infectious colitis, neoplasia and ischemic processes. Following surgical intervention and histopathological examination, AA was confirmed by identification of the parasite within a mesenteric artery. This case highlights an atypical presentation and definitive diagnosis established by histopathology despite negative polymerase chain reaction (PCR) results. This report underscores the importance of including AA in the differential diagnosis of abdominal conditions particularly in endemic regions. It also emphasizes the need for enhanced specificity of serological and molecular diagnostic methods.