Improved computation of individual ZPD in a distance learning system

This paper builds upon theoretical studies in the field of social constructivism. Lev Vygotsky is considered one of the greatest representatives of this research line, with his theory of the Zone of Proximal Development (ZPD). Our work aims at integrating this concept in the practice of a computer-assisted learning system. For each learner, the system stores a model summarizing the current Student Knowledge (SK). Each educational activity is specified through the deployed content, the skills required to tackle it, and those acquired, and is further annotated by the effort estimated for the task. The latter may change from one student to another, given the already achieved competence. A suitable weighting of the robustness (certainty) of student’s skills, stored in SK, and their combination are used to verify the inclusion of a learning activity in the student’s ZPD. With respect to our previous work, the algorithm for the calculation of the ZPD of the individual student has been optimized, by enhancing the certainty weighting policy, and a graphical display of the ZPD has been added. Thanks to the latter, the student can get a clear vision of the learning paths that he/she can presently tackle. This both facilitates the educational process, and helps developing the metacognitive ability self-assessment

MOND's acceleration scale as a fundamental quantity

Some quantum-cosmic scaling relations indicate that the MOND acceleration parameter a_0 could be a fundamental quantity ruling the self-gravitating structures, ranging from stars and globular clusters up to superclusters of galaxies and the whole observed universe. We discuss such coincidence relations starting from the Dirac quantization condition ruling the masses of primordial black holes.Comment: 6 page

Total thyroidectomy associated to chemotherapy in primary squamous cell carcinoma of the thyroid

Primary squamous cell carcinoma of the thyroid (PSCCT) is a rare malignant disease with rapid fatal prognosis. The onset is generally characterized by sudden bilateral latero-cervical lymphadenopathy. The Authors report patient of 58-year-old who referred for evaluation of rapidly aggravating bilateral latero-cervical lymphadenopathy. The US highlighted the presence of a hypoechoic nodular lesion characterized by peri and intra-nodular vascularization. Multilayer CT showed diffused involvement of mediastinal and bilateral latero-cervical lymph nodes, with no evidence of primary pulmonary neoplasia or elsewhere. The patient underwent total thyroidectomy. The peri-isthmic tissue was removed due to the presence of a small roundish formation, that was due to lymph node metastasis at histological examination. Histological diagnosis: PSCCT. The immunohistochemical panel of the thyroid lesion was indispensable for the differential diagnosis between PSCCT, medullary carcinoma, anaplastic carcinoma, and thyroid metastasis of neoplasia with unknown primitiveness. The patient underwent chemotherapeutic treatment with Carboplatin and Paclitaxel with modest improvement of dysphagia symptoms and reduction of 10-15% of the target lesions. The clinical course was characterized by loco-regional progression of the disease with exitus in 10 months after diagnosis. Survival and quality of life after surgical therapy and chemotherapy were like that of patients undergoing only chemotherapy. Due to the extreme rarity of the neoplasia, 60 cases described in Literature, no exclusive guidelines are reported for PSCCT. More extensive case studies are needed to evaluate the effects of total thyroidectomy with intent R0/R1 on improving survival and quality of life of patients with PSCCT

Guantánamo, una historia inconclusa : la perversión del imperio del derecho, desde la administración Bush hasta nuestros tiempos

El trabajo plantea la evolución de la política de Estados Unidos respecto a la Bahía de Guantánamo a la luz del Imperio del Derecho. Para eso, el trabajo fue dividido en diferentes secciones que facilitaran su comprensión. Mientras que en la primera parte se esbozan distintos hechos que evidencian el poco apego a las leyes y el derecho internacional por parte del presidente George W. Bush ante los ataques terroristas del 11 de septiembre del 2001, la segunda parte demuestra un encaminamiento forzado hacia el mismo. La tercera parte, en cambio, manifiesta los desafíos de los nuevos actores, ya sea de la administración Obama o Trump, y el rol creciente de jugadores poco convencionales como las instituciones. Este trabajo concluye con la idea de que ha habido un paulatino cambio en la percepción del Imperio del Derecho, pese a los reiterados obstáculos, lo cual evita que Estados Unidos vuelva al punto de partida

Whole-exome analysis in osteosarcoma to identify a personalized therapy

Osteosarcoma is the most common pediatric primary non-hematopoietic bone tumor. Survival of these young patients is related to the response to chemotherapy and development of metastases. Despite many advances in cancer research, chemotherapy regimens for osteosarcoma are still based on non-selective cytotoxic drugs. It is essential to investigate new specific molecular therapies for osteosarcoma to increase the survival rate of these patients. We performed exomic sequence analyses of 8 diagnostic biopsies of patients with conventional high grade osteosarcoma to advance our understanding of their genetic underpinnings and to correlate the genetic alteration with the clinical and pathological features of each patient to identify a personalized therapy. We identified 18,275 somatic variations in 8,247 genes and we found three mutated genes in 7/8 (87%) samples (KIF1B, NEB and KMT2C). KMT2C showed the highest number of variations; it is an important component of a histone H3 lysine 4 methyltransferase complex and it is one of the histone modifiers previously implicated in carcinogenesis, never studied in osteosarcoma. Moreover, we found a group of 15 genes that showed variations only in patients that did not respond to therapy and developed metastasis and some of these genes are involved in carcinogenesis and tumor progression in other tumors. These data could offer the opportunity to get a key molecular target to identify possible new strategies for early diagnosis and new therapeutic approaches for osteosarcoma and to provide a tailored treatment for each patient based on their genetic profile

Astrophysical structures from primordial quantum black holes

The characteristic sizes of astrophysical structures, up to the whole observed Universe, can be recovered, in principle, assuming that gravity is the overall interaction assembling systems starting from microscopic scales, whose order of magnitude is ruled by the Planck length and the related Compton wavelength. This result agrees with the absence of screening mechanisms for the gravitational interaction and could be connected to the presence of Yukawa corrections in the Newtonian potential which introduce typical interaction lengths. This result directly comes out from quantization of primordial black holes and then characteristic interaction lengths directly emerge from quantum field theory.Comment: 11 page

Ultra-Violet Infinities and Counterterms in Higher Dimensional Yang-Mills

In this letter we investigate the ultra-violet behaviour of four-point one-loop gluon amplitudes in dimensions greater than four coupled to various particles types. We discuss the structure of the counterterms and their inherent symmetries.Comment: 14 pages, LateX, axodra

A rare case of omental extra-gastrointestinal stromal tumor showing two coexisting mutations on exon 14 of the PDGFRA gene

Gastrointestinal stromal tumors (GISTs) are neoplasms arising from mesenchymal cells localized into the muscularis propria of the gastrointestinal (GI) tract [1]; 5% of GISTs are extra-GISTs (EGISTs), as they differently originate from adipose tissue adjacent to the GI tract (omentum and mesentery) or from the pancreas [2]. So far, both GISTs and EGISTs have been managed indistinctively by combining surgery, histopathological distinctive features, imaging, and molecular analysis. Moreover, despite the contribution of defined genetic backgrounds whose influence is acknowledged in this type of tumor (i.e. Carney’s triad or familiar form of GIST), the pathobiology of both GISTs and EGISTs is not yet fully understood. We describe an interesting case of an extensively diffuse EGIST involving only omentum and mesocolon with multinodular growth and peculiar histological features, and for which a deeper histopathological/ molecular analysis is reported. Case presentation A 74-year-old female with a historical diagnosis of multiple myeloma was referred for anemia, alvus disorders (diarrhea and constipation), weight loss (15 kg in 6 months), and palpable mass of the right flank that had appeared 8 weeks before. On medication for multiple myeloma since 2016 (melphalan combined with prednisone and bortezomib9; carfilzomib/lenalidomide/ desametasone6 until complete remission), she also had type II diabetes, treated with oral medications and open cholecystectomy in the 1980s. Physical examination revealed the presence of a large mobile non-painful mass in the right flank apparently from the right colon, without signs of occlusion or intestinal bleeding. Blood analysis showed: hemoglobin 7.9 g/dL, white blood cells 2.3103/lL, glycemia 191 mg/dL, and a low potassium level of 2.8 mEq/L. We first treated the glycemia by insulin infusion and, second, we investigated the signs of anemia. By lower GI Submitted: 14 May 2020; Revised: 20 July 2020; Accepted: 28 July 202

Polypoid lesions of the gallbladder in a consecutive series of 2631 patients. A single-center experience

INTRODUZIONE: La diagnosi ultrasonografica (US) delle lesioni polipoidi della colecisti (PLG) è difficile per la bassa sensibilità (SE) della metodica. Non sono stati ancora completamenti definiti i criteri di selezione dei pazienti con PLG da indirizzare al trattamento chirurgico o al follow-up. L’indagine istopatologica (EI) rappresenta il gold standard per la diagnosi di polipi non-neoplastici (colesterolotici, infiammatori, fibroepiteliali, adenomiomatosici), di polipi neoplastici (carcinomi, carcinoidi), di lesioni precancerose non polipoidi (displasia dibasso ed alto grado, metaplasia intestinale di tipo muciparo, metaplasia gastrica di tipo pilorico) e di irregolarità nodulari parietali della colecistite xanto-granulomatosa. Gli scopi dello studio sono stati quelli di valutare in un campione di pazienti sottoposti a colecistectomia, la prevalenza dei polipi non neoplastici e neoplastici e la sensibilità dell’US tradizionale trans-addominale rispetto all’EI nell’identificazione delle PLG. MATERIALI E METODI: Studio osservazionale retrospettivo, condotto su un campione di 2631 pazienti, sottoposti a colecistectomia laparoscopica e open, in elezione e in urgenza, identificati mediante il codice ICD-9-CM 51.2, nel periodo Aprile 2005 - Marzo 2018, presso l’ospedale universitario “A. Fiorini” di Terracina - Polo Pontino, “Sapienza” Università di Roma. Tutti i pazienti erano stati sottoposti a US. RISULTATI: Il campione esaminato era costituito da 1175(44.6%) M, età media 56 anni, range 25-95 anni, 1456(55.4%) F, età media 46anni, range 17-90 anni. La diagnosi US di PLG veniva posta in 38/2631(1.4%) pazienti. All’esame istologico i polipi erano identificati in 68/2631(2.6%) pazienti, associati a litiasi biliare in 28/2631 (1.1%) casi. Dal confronto US e EI la diagnosi ecografica risultava gravata da falsi positivi (FP) (8/38; 21%) e falsi negativi (FN) (38/2631; 1.45%), con SE 44% (95% c.i.:32.2-55.7). L’incidenza istologica di PLG neoplastiche è stata dello 0.38% (10/2631), 3M e 7F, età media 64 anni, (range 49-80 anni). In 3 casi le neoplasie erano state identificate all’US (3/10; 30 % VP); nei restanti 7 casi costituivano reperto istologico incidentale (7/10; 70 % FN), di cui 5 con diametro >1cm nel contesto di un quadro clinico di colecistite acuta litiasica e 2 con diametro <1cm in un quadro di litiasi non complicata. DISCUSSIONE: L’US tradizionale trans-addominale sottostimava l’incidenza delle PLG rispetto all’EI (p=0.021) e i FP per PLG isolate sono stati causa di errata indicazione al trattamento chirurgico. Il confronto fra diagnosi US ed EI conferma la bassa SE della metodica ecografica nell’identificazione delle PLG, sia in presenza che in assenza di litiasi biliare. Il sesso femminile si è dimostrato specifico fattore di rischio per PLG benigne e maligne e lesioni mucosali non polipoidi (p=0.041). Nel nostro studio, probabilmente, le cause della mancata identificazione US delle irregolarità parietali maligne erano l’oscuramento della lesione dall’esordio clinico della neoplasia in colecistite acuta litiasica (in 5 pazienti) e le dimensioni <1cm in presenza di litiasi non complicata (in 2 pazienti). La dimensione della lesione parietale <0.5cm non escludeva la loro natura neoplastica. Attualmente la prevenzione e la diagnosi di GBC è basata sul precoce riscontro e trattamento delle lesioni polipoidi potenzialmente evolutive nell’arco di circa 15 anni. CONCLUSIONI: Probabilmente la colecistectomia precoce in tutti i pz con PLG di diametro <1cm, isolate o associate a calcoli, sintomatici e asintomatici, può contribuire alla riduzione dell’incidenza del GBC.BACKGROUND: Challenges in the diagnosis of polypoid gallbladder lesion (PLG) is due to the low sensibility (SE) of ultrasound scan (US), and the selection criteria of patients with PLG to be addressed to surgical treatment or followup are not yet fully defined. MATERIALS AND METHODS: Retrospective observational study was conducted on 2631 patients, 1175(44.6%) M, mean age 56 years, 1456(55.4%) F, mean age 46 years, who underwent laparoscopic and open cholecystectomy. RESULTS: The US diagnosis for PLG was placed in 38/2631(1.4%) patients. On histological examination (HE) the polyps were identified in 68/2631(2.6%) patients and it was associated with biliary lithiasis in 28/2631 (1.1%) cases. From the US and HE comparison, the ultrasound diagnosis was burdened by false positives (8/38; 21%) and false negatives (38/2631;1.45%), with SE 44% (95% c.i.:32.2-55.7). The histological incidence of gall bladder cancer (GBC) was 0.38%(10/2631). DISCUSSION: US survey underestimated the incidence of PLG compared to the histological finding (p=0.021). Female gender has been shown to be a specific risk factor for benign and malignant PLG and non-polypoid mucosal lesions (p=0.041). The parietal lesion size <0.5cm does not exclude the neoplastic nature. Currently the prevention and diagnosis of GBC is based on the early detection and treatment of potentially evolutionary polypoid lesions over a period of about 15 years. CONCLUSIONS: It is probably that early cholecystectomy in all the patients with PLG of diameter <1cm, isolated or associated with lithiasis, symptomatic and asymptomatic, can contribute to the reduction of the incidence of GBC