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The objective of this study is to characterize the historical evolution of the improvement of principals´ professional performance in comprehensive schools from Cuba, in the period between 1899 and 2015, considering three indicators: a) the educational context, b) comprehensive schools and their management process, c) conception of the improvement of principals´ performance in comprehensive schools. The study implied the combined use of theoretical methods of (historical-logical and analysis-synthesis methods) and empirical ones (documentary sources and interviews) of educative research. It can be concluded that the study has come to a moment in which the associated process have been most prestiged to its formative and evaluative dimensions in contrass to the its organizational and affective motivational ones, and lacks of an integrative conception that allows to act in favor over the multiplicity of factors that influences the professional performance.

With global warming and rising energy demands, it is important now than ever to transit to renewable energy systems. Thermoelectric (TE) devices can present a feasible alternative to generate clean energy from waste heat. However, to become attractive for large-scale applications, such devices must be cheap, efficient, and based on ecofriendly materials. In this study, the potential of novel silicide-tetrahedrite modules for energy generation was examined. Computer simulations based on the finite element method (FEM) and implicit finite difference method (IFDM) were performed. The developed computational models were validated against data measured on a customized system working with commercial TE devices. The models were capable of predicting the TEGs' behavior with low deviations (≤10%). IFDM was used to study the power produced by the silicide-tetrahedrite TEGs for different ΔT between the sinks, whereas FEM was used to study the temperature distributions across the testing system in detail. To complement these results, the influence of the electrical and thermal contact resistances was evaluated. High thermal resistances were found to affect the devices ΔT up to ~15%, whereas high electrical contact resistances reduced the power output of the silicide-tetrahedrite TEGs by more than ~85%.

Introduction: Large granular lymphocyte (LGL) leukaemia is considered a mature T-cell or natural killer (NK) cell neoplasm, characterised by a clonal proliferation of LGL., Aims: To analyse the characteristics and to establish (if possible) the prognostic parameters of these patients diagnosed in a single centre: University Hospital of Donostia., Methods: We retrospectively studied data about 308 patients with LGL leukaemia diagnosed in our centre., Results: The frequency of T-LGL leukaemia and chronic lymphoproliferative disorder of NK cells was 89% and 6.8% respectively, and no aggressive NK-LGL leukaemia was seen in our population. The median age at diagnosis was 65.7 years and male-to-female ratio was 1.08. 59% of our patients were asymptomatic at the time of diagnosis. Most patients presented lymphocytosis and 63.6% more than 20% LGLs in the peripheral blood count, but it has to be taken into account that these results may be influenced by the selection bias of our study, as we recognised these patients as 'alarms of the laboratory analysers'. Neutropenia was the most common cytopenia, and autoimmune disorders were described in 16.5% of the patients. Only 12 patients (3.9%) required treatment, a much lower percentage that the one reported in the literature, and this is consistent with the fact that patients were less symptomatic than in other series, as we expected. The 5-year and 15-year overall survival was 92% and 87%, respectively., Conclusions: Our patients may represent the even more benign end of the spectrum of clonal T LGL and NK proliferations., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Although there is an important lack of commercial thermoelectric applications mainly due to their low efficiency, there exist some cases in which thermoelectric generators are the best option thanks to their well-known advantages, such as reliability, lack of maintenance and scalability. In this sense, the present paper develops a novel application in order to supply power to volcanic monitoring stations, making them completely autonomous. These stations become indispensable in any volcano since they are able to predict eruptions. Nevertheless, they present energy supply difficulties due to the absence of the power grid, the remote access, and the climatology. As a solution, this work has designed a new integral system composed of thermoelectric generators with high efficiency heat exchangers, and its associated electronics, developed thanks to Internet of Things (IoT) technologies. Thus, the heat emitted from volcanic fumaroles is transformed directly into electricity with thermoelectric generators with passive heat exchangers based on phase change, leading to a continuous generation without moving parts that powers different sensors, the information of which is emitted via LoRa. The viability of the solution has been demonstrated both at the laboratory and at a real volcano, Teide (Canary Islands, Spain), where a compact prototype has been installed in an 82 °C fumarole. The results obtained during more than five months of operation prove the robustness and durability of the developed generator, which has been in operation without maintenance and under all kinds of meteorological conditions, leading to an average generation of 0.54 W and a continuous emission over more than 14 km.

Fumaroles represent evidence of volcanic activity, emitting steam and volcanic gases at temperatures between 70 and 100 ∘ C . Due to the well-known advantages of thermoelectricity, such as reliability, reduced maintenance and scalability, the present paper studies the possibilities of thermoelectric generators, devices based on solid-state physics, to directly convert fumaroles heat into electricity due to the Seebeck effect. For this purpose, a thermoelectric generator composed of two bismuth-telluride thermoelectric modules and heat pipes as heat exchangers was installed, for the first time, at Teide volcano (Canary Islands, Spain), where fumaroles arise in the surface at 82 ∘ C . The installed thermoelectric generator has demonstrated the feasibility of the proposed solution, leading to a compact generator with no moving parts that produces a net generation between 0.32 and 0 . 33 W per module given a temperature difference between the heat reservoirs encompassed in the 69- 86 ∘ C range. These results become interesting due to the possibilities of supplying power to the volcanic monitoring stations that measure the precursors of volcanic eruptions, making them completely autonomous. Nonetheless, in order to achieve this objective, corrosion prevention measures must be taken because the hydrogen sulfide contained in the fumaroles reacts with steam, forming sulfuric acid.

Introduction: We evaluated the value of hematopoietic progenitor cells (HPCs) counted in Sysmex XN analyzers to predict the mobilization and collection of CD34+ cells in apheresis for stem cell transplantation., Methods: Eighty patients who underwent stem cell transplantation were enrolled (50 autologous and 30 allogeneic). In the autologous group, patients were considered poor mobilizers when the CD34+ count was <10 × 10 6 /L or <20 × 10 6 /L in patients with multiple myeloma who were going to undergo two transplants. ROC curves were generated, and HPC cutoffs were calculated., Results: The correlation between the HPC and CD34+ cell counts was good. Two algorithms were proposed. In the first algorithm, samples collected the day before apheresis, negative and positive HPC cutoffs were selected to detect poor and good mobilization and, therefore, the need or not to administer plerixafor. In the second algorithm, samples collected pre-apheresis, the negative HPC cutoff was an indication to delay apheresis; an HPC higher than the optimal cutoff was an indication to start apheresis. When the HPC values were between these cutoffs, there was an indication to count CD34+ cells for a better decision-making. Finally, in samples collected pre-apheresis, HPC counts could be used to predict patients who would have poor CD34+ cell collections. In the allogeneic group, all the donors mobilized well, and very few needed two apheresis procedures., Conclusions: The HPC count is useful for decision-making in the management of patients subjected to apheresis procedures to collect peripheral blood stem cells., (© 2019 John Wiley & Sons Ltd.)

B-cell lymphomas represent a heterogeneous collection of more than twenty-five different malignancies. Classification is often challenging as primarily based upon, sometimes subjective, histopathological criteria and misdiagnosis can result in inappropriate treatment decisions. MicroRNAs (miRNAs) hold great promise as novel biomarkers (diagnostic, prognostic and predictive) of B-cell lymphoma in addition to being potential therapeutic targets. The most promising of these miRNAs more often than not play key regulatory roles in lymphopoiesis (development of lymphocytes) when under physiological conditions, and in the pathology of lymphoid malignancies when aberrantly expressed. In this review we consider the identity and functional role of miRNAs in the most common forms of B-cell lymphomas, their role in lymphopoiesis and their potential as biomarkers for these malignancies.

The effective and efficient management of cancer patients relies upon early diagnosis and/or the monitoring of treatment, something that is often difficult to achieve using standard tissue biopsy techniques. Biological fluids such as blood hold great possibilities as a source of non-invasive cancer biomarkers that can act as surrogate markers to biopsy-based sampling. The non-invasive nature of these "liquid biopsies" ultimately means that cancer detection may be earlier and that the ability to monitor disease progression and/or treatment response represents a paradigm shift in the treatment of cancer patients. Below, we review one of the most promising classes of circulating cancer biomarkers: microRNAs (miRNAs). In particular, we will consider their history, the controversy surrounding their origin and biology, and, most importantly, the hurdles that remain to be overcome if they are really to become part of future clinical practice.