Identifying who adolescents prefer as source of information within their social network.

Adolescents are highly influenced by their peers within their social networks. This social influence can stem from both unsolicited peer pressure and the active search for guidance. While extensive research examined the mechanisms of peer pressure, little is known about who adolescents prefer as a source of information. To address this gap, we conducted two independent studies using a novel social search paradigm that allows participants to choose which social sources they wish to observe. In both studies, adolescents demonstrated a preference for their friends over non-friends, as well as for peers who were perceived as trustworthy. Across both studies, we found mixed evidence for the role of perceived popularity as a selection criterion. Notable, study 2 revealed the significance of "cool", "admirable" and "acting mean" as additional characteristics of preferred peers, traits that are often associated with elevated peer status. It also revealed an interest for peers perceived as being smart. These findings highlight the active role adolescents have in choosing social sources and emphasize the importance of multiple peer characteristics. Future research should investigate whether adolescents' interest in these types of peers is contingent upon specific social contexts, age groups, and peer cultures.

Adolescents seek social information under uncertainty.

Adolescence is a period of emerging independence, in which adolescents face difficult decisions, including those that involve risk for health and well-being. Previous research suggests that learning from others might be a prominent strategy of adolescents to inform these difficult decisions. However, there is a gap in the literature that addresses the active role adolescents may have in gaining information about others' behavior (i.e., social information search). Here, we investigated when and how much social information adolescents search before making decisions under risk and ambiguity, using a novel social search paradigm. In this paradigm, adolescents were able to reveal real information about their classmates' choices before deciding on their final choice. Our two experiments suggest that social information search can be broken down in two independent decisions: first the decision to initiate search, followed by the decision to continue search. Several factors motivated initiation of search, including: (a) the difficulty of the choice, (b) uncertainty about the outcome, and (c) the magnitude of the reward at stake. Search took generally longer when adolescents faced information not in line with their initial preference. Finally, we observed that adolescents used the sampled social information to inform their risky-choice behavior. Taken together, these results provide novel insights into the dynamics of peer influence in adolescence and stress the importance of treating adolescents not only as receivers, but as active agents searching for social information. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Network distance and centrality shape social learning in the classroom.

Social learning can help individuals to efficiently acquire knowledge and skills. In the classroom, social learning often takes place in structured settings in which peers help, support, and tutor each other. Several protocols have been developed to make peer-assisted learning (PAL) more efficient. However, little attention has been devoted to how the transfer of knowledge is shaped by the social relationship between peers, and their relative positions in the social network. To address this gap, we combined social network analysis with an experimental social learning task, in which pupils (N = 135; aged 11-19) could use social information from their peers to improve their performance. We show that pupils' tendencies to use social information substantially decrease with the peer's distance in the social network. This effect is mediated by subjective closeness: pupils report feeling much closer to their friends than to their non-friends, and closeness strongly enhances social learning. Our results further show that, above and beyond these effects of network distance, social information use increases with the peer's social status (network centrality) and perceived smartness. Our results provide empirical evidence in a naturalistic setting for the role of specific network attributes in shaping pupils' willingness to learn from their peers. These findings illustrate the value of a social network approach for understanding knowledge transfer in the classroom and can be used to structure more effective peer learning. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Relationships between nitrogen cycling microbial community abundance and composition reveal the indirect effect of soil pH on oak decline.

Tree decline is a global concern and the primary cause is often unknown. Complex interactions between fluctuations in nitrogen (N) and acidifying compounds have been proposed as factors causing nutrient imbalances and decreasing stress tolerance of oak trees. Microorganisms are crucial in regulating soil N available to plants, yet little is known about the relationships between soil N-cycling and tree health. Here, we combined high-throughput sequencing and qPCR analysis of key nitrification and denitrification genes with soil chemical analyses to characterise ammonia-oxidising bacteria (AOB), archaea (AOA) and denitrifying communities in soils associated with symptomatic (declining) and asymptomatic (apparently healthy) oak trees (Quercus robur and Q. petraea) in the United Kingdom. Asymptomatic trees were associated with a higher abundance of AOB that is driven positively by soil pH. No relationship was found between AOA abundance and tree health. However, AOA abundance was driven by lower concentrations of NH4+, further supporting the idea of AOA favouring lower soil NH4+ concentrations. Denitrifier abundance was influenced primarily by soil C:N ratio, and correlations with AOB regardless of tree health. These findings indicate that amelioration of soil acidification by balancing C:N may affect AOB abundance driving N transformations, reducing stress on declining oak trees.

Intralesional Injection of Triamcinolone Acetonide for Subcutaneous Lipoma causing Musculoskeletal and Neurologic Symptoms.

Objective: Benign subcutaneous lipomas can cause musculoskeletal pain and nerve impingement. We hypothesized that the potent lipolytic and atrophic effect of 40mg/mL triamcinolone acetonide would atrophy symptomatic lipomas so surgical excision could be avoided. Design: This was a cohort study. Setting: This study took place in an ultrasound injection clinic. Participants: Eight subjects with painful symptomatic lipoma were included. Measurements: Preprocedurally, the margins of the lipomas were palpated and marked with ink, then measured in centimeters (cm). Small lipomas (1-3cm) were injected with 40mg triamcinolone acetonide, while large lipomas (4-6cm) were injected with 80mg of triamcinolone acetonide. The subjects were reassessed at a four-month follow-up appointment and then again at one year and two years after the procedure. Results: Pre-injection, all eight subjects had symptoms related to impingement or pain with compression of the lipoma. At four months post-injection, none of the patients had symptoms attributable to the lipoma (p<0.001). The mean lipoma palpable dimension was 5.0±1.2cm prior to the injection and was 2.0±1.1cm at four months after the injection, with a significant mean 3.0±0.3cm (60%) reduction in lipoma dimensions (p<0.001). Two subjects demonstrated some mild hypopigmentation of the skin at four months post-injection. Within two years, three lipomas had symptomatically recurred, one of which was removed surgically and the two of which were reinjected. There were no infections or other serious adverse reactions that occurred. Conclusions: For individuals with painful subcutaneous lipoma, intralesional injection of 40mg/mL of triamcinolone acetonide is an effective and safe alternative to surgical excision or injection of sclerosing agents and should be considered as a reasonable therapeutic alternative in select patients.

Can Diagnostic and Therapeutic Arthrocentesis Be Successfully Performed in the Flexed Knee?

BACKGROUND/OBJECTIVE: The objective of this study was to determine whether the extended or flexed knee positioning was superior for arthrocentesis and whether the flexed knee positioning could be improved by mechanical compression. METHODS: Fifty-five clinically effusive knees underwent arthrocentesis in a quality improvement intervention: 20 consecutive knees in the extended knee position using the superolateral approach, followed by 35 consecutive knees in the flexed knee position with and without an external compression brace placed on the suprapatellar bursa. Arthrocentesis success and fluid yield in milliliters were measured. RESULTS: Fluid yield for the extended knee was greater (191% greater) than the flexed knee (extended knee, 16.9 ± 15.7 mL; flexed knee, 5.8 ± 6.3 mL; P < 0.007). Successful diagnostic arthrocentesis (≥2 mL) was 95% (19/20) in the extended knee and 77% (27/35) in the flexed knee (P = 0.08). After mechanical compression was applied to the suprapatellar bursa and patellofemoral joint of the flexed knee, fluid yields were essentially identical (extended knee, 16.9 ± 15.7 mL; flexed knee, 16.7 ± 11.3 mL; P = 0.73), as were successful diagnostic arthrocentesis (≥2 mL) (extended knee 95% vs. flexed knee 100%, P = 0.12). CONCLUSIONS: The extended knee superolateral approach is superior to the flexed knee for conventional arthrocentesis; however, the extended knee positioning and flexed knee positioning have identical arthrocentesis success when mechanical compression is applied to the superior knee. This new flexed knee technique for arthrocentesis is a useful alternative for patients who are in wheelchairs, have flexion contractures, cannot be supine, or cannot otherwise extend their knee.

Improvement in diagnostic and therapeutic arthrocentesis via constant compression.

We hypothesized that constant compression of the knee would mobilize residual synovial fluid and promote successful arthrocentesis. Two hundred and ten knees with grade II-III osteoarthritis were included in this paired design study: (1) conventional arthrocentesis was performed with manual compression and success and volume (milliliters) determined; and (2) the intra-articular needle was left in place, and a circumferential elastomeric brace was tightened on the knee to provide constant compression. Arthrocentesis was attempted again and additional fluid volume was determined. Diagnostic procedural cost-effectiveness was determined using 2017 US Medicare costs. No serious adverse events were noted in 210 subjects. In the 158 noneffusive (dry) knees, sufficient synovial fluid for diagnostic purposes (≥ 2 ml) was obtained in 5.0% (8/158) without compression and 22.8% (36/158) with compression (p = 0.0001, z for 95% CI = 1.96), and the absolute volume of arthrocentesis fluid obtained without compression was 0.28 ± 0.79 versus 1.10 ± 1.81 ml with compression (293% increase, p = 0.0001). In the 52 effusive knees, diagnostic synovial fluid (≥ 2 ml) was obtained in 75% (39/52) without compression and 100% (52/52) with compression (p = 0.0001, z for 95% CI = 1.96), and the absolute volume of arthrocentesis without compression was 14.7 ± 13.8 versus 25.3 ± 15.5 ml with compression (72.1% increase, p = 0.0002). Diagnostic procedural cost-effectiveness was $655/sample without compression and $387/sample with compression. The new technique of constant compression via circumferential mechanical compression mobilizes residual synovial fluid beyond manual compression improving the success, cost-effectiveness, and yield of diagnostic and therapeutic arthrocentesis in both the effusive and noneffusive knee.