101,550 research outputs found
Il dibattito attorno al Ministero per la Ricostruzione delle Terre Liberate dal Nemico: un'esperienza "Salata" o riuscita?
No full textLa conclusione di una guerra devastante come fu il primo conflitto mondiale aprì ad una serie di delicate questioni di gestione amministrativa, che videro coinvolte le cosiddette Terre Redente, unitamente ai luoghi direttamente interessati al combattimento. Una delle soluzioni fu la creazione di un Ministero ad hoc, con il preciso compito di coordinare la ricostruzione e di indennizzare quanti avevano patito perdite. Fu un vero e proprio laboratorio amministrativo ed istituzionale, tra luci ed ombre
Maktabat Al Muthanna Baghdad Feb-May 1962
No full textOn the same date, Ali Al-Mansouri issued an official financial statement confirming that the Al-Khanji Foundation owed a total of 11.375.أصدر علي المنصوري بيانًا ماليًا رسميًا بتاريخ 25 نيسان 1962 يُفيد بأن مؤسسة الخانجي مدينة بمبلغ إجمالي قدره 11,375
Scritti in onore di Luciano Marchi. Vol. 3: Controllo di gestione
No full textNel Volume III, Controllo di gestione, a cura di Stefano Marasca, Nicola Castellano e Claudia Presti, l’argomento del controllo economico, declinato in quello del controllo di gestione, diviene oggetto degli studi del Marchi al punto che l’idea del controllo-guida orienta la sua decisione verso un nuovo ed ambizioso obiettivo: la nascita della Rivista Management Control. I 21 capitoli del volume mostrano le evoluzioni del tema e come gli aspetti della managerialità e della sostenibilità siano centrali anche nella ricerca di nuovi strumenti del controllo
Symmetry-constrained Monte Carlo to predict the experimental crystal structure of small organic molecules
No full textCrystal structure prediction (CSP) remains a pivotal challenge in the field of material science,[1-3] with strong implications that span diverse domains from pharmaceuticals to advanced materials engineering. Despite the strong efforts and the significant progress achieved in the last years, the accurate prediction of the most thermodynamically stable polymorphs remains and intricate endeavour, especially for flexible organic molecules with numerous degrees-of-freedom.[4-5] Many software solutions employ brute force algorithms, to generate putative structures, ranked based on specific criteria such as packing efficiency, cohesive energy and others.
To address this challenge, we presented a novel multi-step method that take into consideration both the thermodynamics and the dynamical stability of crystals.[6] First, we use a symmetry-constrained Monte Carlo (SC-MC) algorithm to produce a set of thermodynamically plausible crystalline structures. This method shares the same philosophy of the Milano Chemistry Molecular Simulation (MiCMoS) platform [7] and, in addition, exploit the presence of the lattice symmetries. In this way, only the symmetry-independent part of the system is refined, with a significant saving in terms of computational time. Subsequently, the selected plausible structures undergo short classical molecular dynamics to assess their mechanical stability. Finally, the remaining stables structures are treated using solid-state Quantum Mechanical software, e.g. CRYSTAL,[8] to extract more reliable cohesive energies.
Our approach is validated through comprehensive testing on various organic molecules intended for pharmaceutical and biological applications. A primary emphasis is placed on the investigation of active pharmaceutical ingredients and their potential phase transitions under diverse experimental conditions, as well as the formation of co-crystals. The obtained results demonstrate a sufficient level of accuracy in the crystal prediction when compared against existing experimental structures, although challenges persist in complex cases. A comparison with the outcomes of other CSP software will be taken into consideration. To further improve the accuracy of the proposed method, future works may focus on developing a new ad hoc force field tailored for the purpose.
[1] Gavezzotti, A. (1991) J. Am. Chem. Soc. 113, 4622.
[2] Price, S. L. (2014) Chem. Soc. Rev. 43, 2098.
[3] Macetti, G., Sironi, L., Lo Presti, L. (2024) Compr. Comput. Chem. 3, 777.
[4] Bowskill, D. H., Sugden, I. J., Konstantinopoulos, S., Adjiman, C. S., Pantelides, C. C. (2021) Annu. Rev. Chem. Biomol. Eng. 12, 593.
[5] Reilly, A. M. et al. (2016) Acta Cryst. B. 72, 439.
[6] Macetti, G., Sironi, L., Lo Presti, L. (2024) in preparation.
[7] Gavezzotti, A., Lo Presti, L., Rizzato, S. (2022) CrystEngComm 24, 922.
[8] Erba, A. et al. (2023) J. Chem. Theory Comput. 19, 6891
Qilādat al-jawāhir fī dhikr al-Ghawth al-Rifāʻī wa-atbāʻih al-akābir
No full textA book on Sufism on the Rifa'i way, in which the author collects virtues, conditions, dignity, sayings, behavior, method, and the realizations of the truth of Sheikh Ahmed Muhyi al-Din Abu al-Abbas al-Kabeer al-Rifa'i. Furthermore, the user talked about the widespread support he receives from his followers and the key aspects of his method
Preliminary Validation of a Novel Method for the Assessment of Effective Stress State in Partially Saturated Soils by Cone Penetration Tests
No full textA proper assessment of the soil effective stress state is crucial in many cases to identify a potential geological/geotechnical hazard as shallow landslides or failure of levees that may have a significant impact on human activities and development. This paper is aimed at validating a methodology for the expeditious and economic determination of effective stress state in the vadose zone recently proposed by Lo Presti et al. in 2016. The method is based on the interpretation of cone penetration tests (CPTu). Its validation was carried out by comparing the CPTu predicted values of suction against the measured ones in a well-documented and monitored site. The comparison also includes the prediction of suction that was obtained by using the so-called Modified Kovacs model (MK). Moreover, additional data of water content and saturation degree from another site were used to predict the suction by using the MK model. These values of suction were compared with those inferred by the CPTu
Source function applied to experimental densities reveals subtle electron delocalization effects and appraises their transferability properties in crystals
No full textThe Source Function (SF) [1] enables the electron density (ED) to be seen at a point as determined by source contributions from the atoms of a system, and it is therefore well linked to the chemist’s awareness that any local property and chemical behaviour is to some degree influenced by all the remaining parts of a system [1-3]. The key feature of the SF is that its evaluation requires only knowledge of the ED of a system, enabling a comparison of ab initio and X-ray diffraction derived ED properties on a common, rigorous basis. We here apply the SF descriptor to X-ray derived EDs as a mean to reveal electron-delocalization effects (EDEs) in crystals. Use of the SF to detect them has been firmly assessed for isolated molecules and for theoretically-derived EDs [2,4-5], but extending to crystals and experimental EDs, although being reported at two conferences [6-7] and in two papers discussing heteroaromaticity in a benzothiazol-substituted phosphane [8] or antiaromaticity in cyclopentadienone derivatives [9] needs to be fully demonstrated. Still unanswered questions are whether the EDs from X-ray data may be accurate enough to reveal the subtle features caused by electron pairing and whether these are not only detectable, but also reproducible and transferable, whenever appropriate. To provide an answer we analyse the experimental SF patterns in benzene (BZ), naphthalene (NT) and (+/-)-8’-benzhydrylideneamino-1,1’-binaphtyl-2-ol (BAB) molecular crystals. We find that the SF tool recovers the characteristic SF% patterns caused by pi-electron conjugation in the first two paradigmatic aromatic molecules in almost perfect quantitative accord with those from ab initio periodic calculations [10]. Moreover, the effect of chemical substitution on the transferability of such patterns to the BZ- and NT-like moieties of BAB is neatly spotted by the observed systematic deviations, relative to BZ and NT, of only those SF contributions from the substituted C atoms [10]. The capability of the SF to reveal EDEs by using a promolecule ED (PED), rather than the “true” ED, is then tested; the PED seems unable to reproduce the SF trends anticipated by the increase of electron delocalization [10].
The SF has wider applications than those related to the nature of chemical bonds in more or less conventional situations [2-3]. Detection of EDEs is one such new direction, another being the extension of the SF machinery to retrieve the atomic sources of the spin ED [5,11].
Acknowledgements
Prof. Sine Larsen and Prof. Mark Spackman are both warmly thanked for providing us with, respectively, the 135 K X-ray diffraction dataset of naphthalene crystal and the 110 K X-ray diffraction data set of benzene. The Danish National Research Foundation is also thanked for partial funding of this work through the Center for Materials Crystallography (DNRF93).
References
[1] Bader, R. F. W. & Gatti, C. (1998). Chem. Phys. Lett. 287, 233-238.
[2] Gatti, C. (2012). Struct. Bond. 147, 193-286.
[3] Gatti, C. (2013). Phys. Scripta 87, 048102 (38pp).
[4] Monza, E., Gatti, C., Lo Presti, L. & Ortoleva, E. (2011). J. Phys. Chem. A 115, 12864–12878.
[5] Gatti, C., Orlando, A. M., Monza, E. & Lo Presti, L. (2016). Applications of Topological Methods in Molecular Chemistry, edited by R. Chauvin, C. Lepetit, B. Silvi & E. Alikhani, p. XXXX-YYYY, in Springer series Challenges and Advances in Computational Chemistry and Physics 22, Springer International Publishing, DOI 10.1007/978-3-319-29022-5_5
[6] Gatti, C., Saleh, G., Lo Presti, L. et al. (2012). In: Abstracts (page 42) of the Sagamore meeting XVII on Charge Spin and Momentum Densities, Daini Meisui Tei, Sapporo, Hokkaido, Japan, 15-20 July.
[7] Gatti, C. (2013). In: Abstracts of Natta’s Seeds Grow, From the crystallography and modelling of stereoregular polymers to the challenges of complex systems, International symposium on occasion of the 50th anniversary of the award of the Nobel Prize for Chemistry to Giulio Natta and Ziegler, Politecnico di Milano, Italy, 21-22 November.
[8] Hey, J., Leusser, D., Kratzert, D., Fliegl, H., Dieterich, J. M., Mata, R. A. & Stalke, D. (2013). Phys. Chem. Chem. Phys. 15, 20600-20610.
[9] Pal, R., Mukherjee, S., Chandrasekhar, S. & Guru Row, T. N. (2014). J. Phys. Chem. A, 118, 3479–3489.
[10] Gatti, C., Saleh, G. & Lo Presti, L. (2016). Acta Cryst. B72, doi:10.1107/S2052520616003450
[11] Gatti, C., Orlando, A. M. & Lo Presti, L. (2015). Chem. Sci. 6, 3845-3852
MITO per la città - Alessandro Molinaro e Carlo Lo Presti al Teatro della Divina Provvidenza
No full textAlessandro Molinaro, flautoCarlo Lo Presti, chitarr
A novel quasi-open loop architecture for GNSS carrier recovery systems
No full textThe problem of designing robust systems to track global navigation satellite system (GNSS) signals in harsh environments has gained high attention. The classical closed loop architectures, such as phase locked loops, have been used for many years for tracking, but in challenging applications their design procedure becomes intricate. This paper proposes and demonstrates the use of a quasi-open loop architecture to estimate the time varying carrier frequency of GNSS signals. Simulation results show that this scheme provides an additional degree of freedom to the design of the whole architecture. In particular, this additional degree of freedom eases the design of the loop filter in harsh environment
Self-Assessment Tools and Participatory Techniques. A Zoom on the Dyad “Rubrics” and “Online Focus Groups”
No full textIn the methodologies for evaluation the use of rubrics as a specific tool for competences assessment (Cortoni & Lo Presti, 2018) is supported by a wide research tradition, especially in the pedagogical field, that has circumscribed their application within dynamic learning contexts (Davidson, 2005). In didactic-educational environments, the administration of self-assessment rubrics can accompany and assist the learning process of students, stimulating in them the acquisition of critical self-reflection skills and drawing attention to those fields of experience that are traditionally connected to the teacher’s evaluative sphere (performance assessment, learning tasks, innovative teaching processes, etc.) (Dawson, 2015). In the research The Social Impact Assessment of DaD after COVID-19, promoted and funded by Sapienza University of Rome, combining tools for competences self-assessment (rubrics) and participatory research techniques (focus groups) has been particularly fruitful since it has helped students discuss themain changes experienced because of the pandemic regarding: i. learning styles; ii. leisure activities; iii. relationships with classmates and teachers. Combined with online participatory techniques, rubrics have maintained their nature as a non-reactive tool (Ametranoet al.,2001). In particular, the dialogic dimension generated by the focus group has made possible to neutralize the distorting effects associated with the concept of performance, preventing respondents from providing answers conditioned bysocial desirability. This has made possible to focus the discussion on specific aspects of the individual’s experience, making the scoring process more closely aligned with the lived experience
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