The time is out of joint. Teacher subjectivity during COVID‑19

In this study, we address the issue of mathematics teachers' personal and professional responsiveness to changing circumstances, such as the shift in external demands made on teacher practice due to the COVID-19 pandemic. For investigating a such delicate issue, we take a theoretical approach, which is quite novel in the field of mathematics education: Lacan's psychoanalytical lens. Specifically, we will use this psychoanalytical lens to analyze a case study focusing on a primary school teacher during the first lockdown in Italy, during which school was organized exclusively in the form of distance education. The analysis of the teacher’s crisis and the strategies she adopted to overcome this crisis give some suggestions about possible directions and issues to consider for future mathematics teacher training proposals

Nonlinear dynamic analysis of gas turbine combustor leaf seal

The leaf seals are one of the typical sealing systems in gas turbine and jet engines. In Baker Hughes LT family gas turbines, they are used to create sealing between the combustion chamber and the first stage nozzle. The leaf seals are thin metallic plates and subjected to dynamic loads and high temperatures. They have curved contacts, and depending on the inclination, they can experience partial contact. Furthermore, when excited by dynamic loads, the leaf seal can be subject to intermittent contact, possibly triggering wear out or vibratory phenomena. Due to its flexibility and its partial seating, it exhibits a complex nonlinear dynamic behaviour, strongly variable with the operating conditions. This study presents a numerical investigation using coupled static/dynamic harmonic balance method (HBM) frequency-based solution technique. The reported solutions include nonlinear forced response and contact studies for various operating and kinematic conditions along with brief insights

High air temperatures induce temporal, spatial and social changes in the foraging behaviour of wild zebra finches

Understanding how heatwaves affect organisms is becoming an important issue in animal behaviour, given the changing climate. Exposure to high air temperatures can lead to lethal hyperthermia, when individuals are no longer able to maintain body temperature within their optimal physiological range. Animals will rapidly adjust their behaviour, prioritizing heat dissipation through activities such as drinking and sitting in shade to maintain their body temperature over other activities, such as foraging. Here, we used an automated logging system to consider both the spatial and temporal foraging patterns under a range of different air temperatures at an individual level, in a strictly granivorous species in the wild. We continuously monitored individual foraging activity of wild zebra finches, Taeniopygia guttata, a species well adapted to arid conditions, in an Australian arid area across two heatwave events. High air temperatures significantly reduced foraging activity, with the extent of this effect depending on the time of day. They also led to a significant decrease in the number of birds foraging together and to birds spending a higher proportion of their foraging activity close to a water supply. As temperatures exceeded 35 °C we saw a significant escalation of heat dissipation behaviour. Our results indicate that extreme air temperatures significantly affected temporal, social and spatial characteristics of zebra finch foraging behaviour and these are likely to adversely reduce an individual's capacity to forage efficiently, and consequently its food intake in the short term, while also potentially having implications for both reproduction and survival in the long term

A caccia di significati matematici attraverso il confronto: sinergia di algoritmi per la moltiplicazione

L'articolo si occupa di mostrare le potenzialità della sinergia di algoritmi differenti (in questo caso della moltiplicazione), per sviluppare nelle bambine e nei bambini significati matematici specifici (in questo caso legati al pensiero moltiplicativo

Issue about culture, affect and standardized assesment

In this chapter we introduce some literature on the influence of culture on mathematics education, specifying the reasons why the cultural aspects are important in research on educational issues. We use this introduction to address the issue of the lack of studies regarding the cultural beliefs underlying national standardized assessment. A comparison among some features of standardized assessment in different European countries is carried out in order to highlight aspects that could be related to such beliefs, and that we hope will be better investigated in further studie

2876. Esercizio di un apprendista scriba

Prima edizione di un papiro greco databile al 160/161 che conserva formulari per imparare a stilare documenti privati e pubblici

O.Petr.Mus. 516, Lettera?

Ed.pr. del testo greco di età bizantina conservato su una scheggia di calcare; quel che resta sembra adattarsi al testo di una lettera