Role of an artefact of Dynamic algebra in the conceptualisation of the algebraic equality

In this contribution, we explore the impact of Alnuset, an artefact of dynamic algebra, on the conceptualisation of algebraic equality. Many research works report about obstacles to conceptualise this notion due to interference of the previous arithmetic knowledge. New meanings need to be assigned to the equal sign and to letters used in algebraic expressions. Based on the hypothesis that Alnuset can be effectively used to mediate the conceptual development necessary to master the algebraic equality notion, two experiments have been designed and implemented in Italy and in France. They are reported in the second part of this pape

Using Alnuset to construct the notions of equivalence and equality in algebra

We analyse the role of technology in the development of algebraic crucial knowledge and competences, such as those involved in the comprehension and use of the notions of equivalence and equality. The hypothesis of our research is that technology can be exploited to make available new operative and representative possibilities which structure a new phenomenological space to investigate the algebraic knowledge and to improve the teaching and learning processes of algebra. We analyse the characteristics of the phenomenological space structured by Alnuset, a system developed by the authors within ReMath European project. Through examples taken from experimentations that we have performed with Alnuset, we illustrate and discuss how such characteristics can be exploited to develop competences and knowledge in the algebraic domain and to improve the teaching of algebra

Morphological and physiological adaptations of wood-boring beetle larvae in timber

Beetles which develop boring tunnels inside and feed on seasoned wood present morphological and physiological adaptations related to the specific activities of their larvae in such a peculiar substrate. As far as protection of antiquarian goods made of wood is concerned, we are dealing mainly with three Coleoptera families, namely Lyctidae, Anobiidae, and Cerambycidae, which include species with wood-boring larvae. The adaptation to wood-boring and wood-feeding activities in beetle larvae was reached independently by phyletic lines not closely related, as a convergent evolution due to feeding behaviour. Among these adaptations, the following are examined with reference to the three families mentioned above. The conformation and activity of the larval mandibles and their possible correlations with the characteristics of the wood attacked are considered together with the presence of body structures for anchoring the larvae to the wood substrate inside the tunnel during the gnawing action. Intracellular endosymbiosis (endocytobiosis) with yeasts or bacteria, capable of supplementing larval diets lacking in some essential nutrients, and its main features are summarized. Last, structural and functional characteristics are discussed as regards tracheal spiracles, provided with filter devices important for preventing intrusion of wood powder into tracheae from larval tunnels as well as useful for avoiding dehydration

Antennal sensilla of Anagrus atomus (L.) (Hymenoptera: Mymaridae) female and their possible behavioural significance

The antennae of a hymenopteran Mymaridae female, Anagrus atomus (L.), have been investigated, through light microscopy as well as through scanning for the first time, and transmission electron microscopy, principally aiming at identification of sensory structures possibly involved in reproductive behaviour. Topographic distribution of the external components (cuticular appendages) of sensilla has been illustrated through “camera lucida” semischematic diagrams of the whole antenna, and especially the club, together with scanning electron micrographs. Topographic location of the same sensilla internal (cellular) components has been shown in the antennal club through transmission electron micrographs from serial cross sections. Seven categories of sensory structures have been identified (i.e., “apical sensilla”, “grooved peg sensilla”, “sensilla trichodea Type 1”, “sensilla trichodea Type 2”, “sensory ridges”, “sunken peg sensilla”, “tactile sensilla”) and illustrated through semischematic diagrams and transmission electron micrographs from fine serial sections. On the basis of the nature of the sensilla and their location on the antennae, together with antennal use during the female reproductive behaviour, the behavioural meaning of the above mentioned sensilla has been hypothesised. INDEX DESCRIPTORS (in addition to those in the title): contact chemoreceptor, olfactory sensilla, reproductive behaviour, sensory neurones, sheath cells, ultrastructure.  SENSILLI ANTENNALI DELLA FEMMINA DI anagrus atomus (L.) (HYMENOPTERA: MYMARIDAE) E RELATIVO PROBABILE SIGNIFICATO COMPORTAMENTALE Le antenne della femmina di un imenottero Mymaridae, Anagrus atomus, vengono studiate in microscopia ottica ed elettronica a scansione e, per la prima volta, a trasmissione, principalmente al fine di identificarne le strutture sensoriali presumibilmente impegnate nel comportamento riproduttivo della specie. La distribuzione topografica degli elementi esterni (appendici cuticolari) dei sensilli viene illustrata con disegni semischematici dell’antenna intera e della clava in particolare, effettuati al microscopio ottico con camera lucida, unitamente a micrografie elettroniche a scansione. La localizzazione topografica delle parti interne (componenti cellulari) degli stessi sensilli viene evidenziata nella clava mediante micrografie elettroniche a trasmissione di sezioni fini trasversali seriate. Sette categorie di sensilli vengono così identificate (“apical sensilla”, “grooved peg sensilla”, “sensilla trichodea Type 1”, “sensilla trichodea Type 2”, “sensory ridges”, “sunken peg sensilla”, “tactile sensilla”) ed illustrate con disegni semischematici riassuntivi e con micrografie elettroniche a trasmissione di sezioni fini seriate. Sulla base della natura dei sensilli e della loro posizione sull’antenna, unitamente al portamento delle antenne medesime durante il comportamento riproduttivo della femmina, viene ipotizzato il significato comportamentale dei sensilli in questione. Parole chiave: cellule avvolgenti, comportamento riproduttivo, neuroni sensoriali, sensilli gustativi, sensilli olfattivi, ultrastruttura

Controlled atmospheres against insect pests in museums: a review and some considerations

Controlled atmospheres using nitrogen represent a safe and effective method for both objects and human health. The use of this technique against pests in museums has received an increasing amount of interest during the last twenty years. This paper looks at the researches into anoxic treatments that use nitrogen from the late ‘80s until now. At the moment, the recommended protocol suggests an oxygen percentage below 1% for at least three weeks. Considering that the major practical problems of controlled atmospheres are connected to treatment time and low oxygen percentage, it is very important to develop more flexible protocols that consider higher oxygen percentages or shorter treatment times, exploiting temperature and/or relative humidity. At oxygen percentage higher than those commonly used, temperature and relative humidity are very critical to insects’ development and success. Preliminary data (unpublished) show that it is possible to adapt the application of the controlled atmospheres to different situations, taking advantage of favorable conditions already present in the considered situation and at the same time to use the other parameters at more favorable levels

Tuberculosis and HIV co-infection in children

HIV is the top and tuberculosis is the second leading cause of death from infectious disease worldwide, with an estimated 8.7 million incident cases of tuberculosis and 2.5 million new HIV infections annually. The World Health Organization estimates that HIV prevalence among children with tuberculosis, in countries with moderate to high prevalence, ranges from 10 to 60%. The mechanisms promoting susceptibility of people with HIV to tuberculosis disease are incompletely understood, being likely caused by multifactorial processes. Paediatric tuberculosis and HIV have overlapping clinical manifestations, which could lead to missed or late diagnosis. Although every effort should be made to obtain a microbiologically-confirmed diagnosis in children with tuberculosis, in reality this may only be achieved in a minority, reflecting their paucibacillary nature and the difficulties in obtain samples. Rapid polymerase chain reaction tests, such as Xpert MTB/RIF assay, are increasingly used in children. The use of less or non invasive methods of sample collection, such as naso-pharyngeal aspirates and stool samples for a polymerase chain reaction-based diagnostic test tests and mycobacterial cultures is promising technique in HIV negative and HIV positive children. Anti-tuberculosis treatment should be started immediately at diagnosis with a four drug regimen, irrespective of the disease severity. Moreover, tuberculosis disease in an HIV infected child is considered to be a clinical indication for initiation of antiretroviral treatment. The World Health Organization recommends starting antiretroviral treatment in children as soon as anti-tuberculosis treatment is tolerated and within 2- 8 weeks after initiating it. The treatment of choice depends on the child’s age and availability of age-appropriate formulations, and potential drug interactions and resistance. Treatment of multi-drug resistant tuberculosis in HIV-infected children follows same principles as for HIV uninfected children. There are conflicting results on effectiveness of isoniazid preventive therapy in reducing incidence of tuberculosis disease in children with HIV. CONCLUSION: Data on HIV/TB co-infection in children are still lacking. There are on-going large clinical trials on the prevention and treatment of TB/HIV infection in children that hopefully will help to guide an evidence-based clinical practice in both resource-rich and resource-limited settings

congenital tuberculosis after in vitro fertilization presenting with endobronchial granuloma

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Vitamin D and tuberculosis: A multicenter study in children

BACKGROUND: The aim of this study is to evaluate vitamin D levels in children with latent and active TB compared to healthy controls of the same age and ethnical background. METHODS: A multicenter observational study has been conducted in three tertiary care paediatric centres: Anna Meyer Children's University Hospital, Florence, Italy; Evelina London Children's Hospital, London, United Kingdom and Great Ormond Street Hospital, London, United Kingdom. Vitamin D was considered deficient if the serum level was <25 nmol/L, insufficient between 25 and 50 nmol/L and sufficient for a level >50 nmol/L. RESULTS: The study population included 996 children screened for TB, which have been tested for vitamin D. Forty-four children (4.4%) had active TB, 138 (13.9%) latent TB and 814 (81.7%) were controls. Our study confirmed a high prevalence of hypovitaminosis D in the study population. A multivariate analysis confirmed an increased risk of hypovitaminosis D in children with latent and active TB compared to controls [(P = 0.018; RR = 1.61; 95% CI: 1.086-2.388), (P < 0.0001; RR = 4.587; 95% CI:1.190-9.608)]. CONCLUSIONS: Hypovitaminosis D was significantly associated with TB infection in our study. Further studies are needed to evaluate a possible role of vitamin D in the treatment and prevention of tuberculosis in children. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-014-0652-7) contains supplementary material, which is available to authorized users

Discomfort relief after paracetamol administration in febrile children admitted to a third level paediatric emergency department

Backgroundinternational guidelines recommend treating fever in children not at a predefined body temperature limit but based on the presence of discomfort. However few studies evaluated discomfort relief after administration of antipyretics in children.MethodsBetween 1st January and 30th September 2021 a single-center prospective observational study was performed in febrile children consecutively admitted to a pediatric emergency department and treated with paracetamol orally. For each child, body temperature, presence and severity of discomfort, defined using a previously published semiquantitative likert scale, were evaluated at baseline and 60 min after administration of paracetamol, and differences were analyzed.Results172 children (males: 91/172; 52.9%; median age: 41.7 months) were included. Significant reductions in body temperature (median body temperature at T0: 38.9 °C; IQR: 38.3–39.4, median body temperature at T60: 36.9 °C; IQR: 36.4–37.5; P Conclusionsparacetamol in febrile children is associated not only with significantly reduction in body temperature but also with discomfort relief.</p

Tuberculosis in childhood: a systematic review of national and international guidelines

BACKGROUND: Paediatric tuberculosis (TB) represents a major public health concern worldwide. About 1 million children aged less than 15 years develop TB each year, contributing to 3-25% of the total TB caseload. The aim of this review is to evaluate national and international guidelines concerning tuberculosis in childhood and compare them in terms of diagnosis and treatment strategies. METHODS: A literature search of the Pubmed database was performed from January 2000 to August 2013, using the terms “tuberculosis” and “children”. The search was limited to guidelines and consensus conferences, human species and full text availability, with no language restrictions. RESULTS: Twenty-seven national and international guidelines are identified. Several discrepancies on the diagnosis workup of TB are underlined. The main points of disagreement are represented by the interpretation of tuberculin skin test (TST) result and the recommendations on the use of TST and/or interferon-gamma release assay (IGRA) for the diagnosis of TB infection. Otherwise, all guidelines are in agreement that a microbiological confirmation should always be sought. Similarly, susceptibility drug testing and genotyping should be performed whenever it is possible on the basis of resources availability. On the contrary, the use of nucleic acid amplification tests (NAATs) for the M. tuberculosis detection is still controversial. A general consensus exists, otherwise, on TB treatment and only minor discrepancies are evidenced, such as the recommendations on daily or intermittent treatment regimens. CONCLUSIONS: Despite advances in TB diagnostic tools have been reached during the last decade, a lack of uniformity in their availability, indication and interpretation has relevant consequences for clinical practice. Further studies need to be performed to clarify this issue and identify a reliable and reproducible diagnostic workup. Moreover, future studies should analyze the drug metabolism and the efficacy of intermittent dosing regimes in childhood, as well as new treatment regimens in order to improve the therapy compliance