SolarStat: Modeling Photovoltaic Sources through Stochastic Markov Processes

In this paper, we present a methodology and a tool to derive simple but yet accurate stochastic Markov processes for the description of the energy scavenged by outdoor solar sources. In particular, we target photovoltaic panels with small form factors, as those exploited by embedded communication devices such as wireless sensor nodes or, concerning modern cellular system technology, by small-cells. Our models are especially useful for the theoretical investigation and the simulation of energetically self-sufficient communication systems including these devices. The Markov models that we derive in this paper are obtained from extensive solar radiation databases, that are widely available online. Basically, from hourly radiance patterns, we derive the corresponding amount of energy (current and voltage) that is accumulated over time, and we finally use it to represent the scavenged energy in terms of its relevant statistics. Toward this end, two clustering approaches for the raw radiance data are described and the resulting Markov models are compared against the empirical distributions. Our results indicate that Markov models with just two states provide a rough characterization of the real data traces. While these could be sufficiently accurate for certain applications, slightly increasing the number of states to, e.g., eight, allows the representation of the real energy inflow process with an excellent level of accuracy in terms of first and second order statistics. Our tool has been developed using Matlab(TM) and is available under the GPL license at[1].Comment: Submitted to IEEE EnergyCon 201

ASSOCIATION OF CALCIFEDIOL LEVELS WITH VERTEBRAL FRACTURES, VASCULAR CALCIFICATIONS AND MORTALITY.

The best biomarker of Vitamin D status is calcifediol [25(OH)D]. We investigated the relationship between serum calcifediol levels and vertebral fractures (VF), vascular calcifications (VC) and mortality in hemodialysis patients. Within a multicenter, cross-sectional study in 18 hospital based dialysis centers in Italy, we included 387 hemodialysis patients (143 F, 37% ; 244 M, 63%), mean age 64±14 (SD) years, median dialytic age 49 months, BMI 25± 4 Kg/m2. We determined total 25(OH)D using the LIASON® 25 OH Vitamin D kit (DiaSorin Inc., Stillwater MN, USA). We evaluated VF with a computerized analysis of scanned L-L vertebral X-rays (T4 to L5). Reduction of > 20% of vertebral body height was considered a VF, while reductions between 15% and 20% were considered borderline fractures (BF). Fracture severity was estimated as mild, moderate or severe (reduction: 20–25%, 25–40% or >40%, respectively). VC assessments were also centralized. Witteman's method (Lancet, 1994) was used for blinded assessments in duplicate. VC were quantified by measuring the length of calcific deposits along the anterior and posterior wall of the aorta (mild 0.1-5 cm, moderate 5.1-10 cm and severe >10 cm). We also evaluated the presence or absence of calcifications of the iliac arteries in the same radiograph (mild 0.1-3 cm, moderate 3.1-5 cm and severe >5cm). Any differences in VC were resolved by consensus. Follow up was 2.7±0.5 years. Bone markers were: Ca 9.15±0.68 mg/dl, P 4.8± 1.28 mg/dl, median ALP 83 U/L and median PTH 244 pg/ml. We found a median 25(OH)D level of 28.9 ng/ml. Nine ( 2.3%) patients had vitamin D deficiency (30 ng/ml). We found that 55% of patients had VF and 30.9% of patients had BF. Prevalence of VC was 80.6% (mild 20.1%, moderate 30.8%, severe 29.7%) in the aorta and 55,1% in the iliac arteries. Males had more VF than Females (60% versus 48%, P=0.019). No associations were found between VF and biochemical parameters including calcifediol levels (p=0.662), while we found an association between low calcifediol levels and a higher prevalence of severe aortic calcifications (36.8 vs 28.2, p=0.0044). Furthermore, we found a OR 1.85 (1.04-3.29 CI, p=0.0367) for Aortic Calcification in patients with calcifediol levels lower than the median value of 29 ng/ml. During follow-up (2.7±0.5 years) mortality was of 19.9%. No association was found between mortality and calcifediol levels (p=0.5394). In conclusion, despite good control of bone and mineral metabolism parameters, hemodialysis patients showed high prevalence of VF and VC. Our study suggests that high calcifediol levels could be protective against progression of severe aortic calcificatio

Learning from the COVID-19 pandemic in Italy to advance multi-hazard disaster risk management

COVID-19 challenged all national emergency management systems worldwide overlapping with other natural hazards. We framed a ‘parallel phases’ Disaster Risk Management (DRM) model to overcome the limitations of the existing models when dealing with complex multi-hazard risk conditions. We supported the limitations analysing Italian Red Cross data on past and ongoing emergencies including COVID-19 and we outlined three guidelines for advancing multi-hazard DRM: (i) exploiting the low emergency intensity of slow-onset hazards for preparedness actions; (ii) increasing the internal resources and making them available for international support; (iii) implementing multi-hazard seasonal impact-based forecasts to foster the planning of anticipatory actions

Preferential expression of mutant ABCD1 allele is common in adrenoleukodystrophy female carriers but unrelated to clinical symptoms

<p>Abstract</p> <p>Background</p> <p>Approximately 20% of adrenoleukodystrophy (X-ALD) female carriers may develop clinical manifestations, typically consisting of progressive spastic gait, sensory deficits and bladder dysfunctions. A skewing in X Chromosome Inactivation (XCI), leading to the preferential expression of the X chromosome carrying the mutant <it>ABCD1 </it>allele, has been proposed as a mechanism influencing X-linked adrenoleukodystrophy (X-ALD) carrier phenotype, but reported data so far are conflicting.</p> <p>Methods</p> <p>To shed light into this topic we assessed the XCI pattern in peripheral blood mononuclear cells (PBMCs) of 30 X-ALD carriers. Since a frequent problem with XCI studies is the underestimation of skewing due to an incomplete sample digestion by restriction enzymes, leading to variable results, we developed a pyrosequencing assay to identify samples completely digested, on which to perform the XCI assay. Pyrosequencing was also used to quantify <it>ABCD1 </it>allele-specific expression. Moreover, very long-chain fatty acid (VLCFA) levels were determined in the same patients.</p> <p>Results</p> <p>We found severely (≥90:10) or moderately (≥75:25) skewed XCI in 23 out of 30 (77%) X-ALD carriers and proved that preferential XCI is mainly associated with the preferential expression of the mutant <it>ABCD1 </it>allele, irrespective of the manifestation of symptoms. The expression of mutant <it>ABCD1 </it>allele also correlates with plasma VLCFA concentrations.</p> <p>Conclusions</p> <p>Our results indicate that preferential XCI leads to the favored expression of the mutant <it>ABCD1 </it>allele. This emerges as a general phenomenon in X-ALD carriers not related to the presence of symptoms. Our data support the postulated growth advantage of cells with the preferential expression of the mutant <it>ABCD1 </it>allele, but argue against the use of XCI pattern, <it>ABCD1 </it>allele-specific expression pattern and VLCFA plasma concentration as biomarkers to predict the development of symptoms in X-ALD carriers.</p

Building design capabilities: a focus on knowledge systematisation within firms

Trabajo presentado a la 35th DRUID Celebration Conference on Innovation, Strategy and Entrepreneurship celebrada en Barcelona (España) del 17 al 19 de Junio de 2013.Scholarly efforts within the evolutionary theories of the firm are increasingly attempting to bridge the micro and macro perspectives of capabilities research to learn more about the growth of the firm. This paper tackles this challenge by proposing a focus on the mechanisms of knowledge systematisation within firms, that is, those mechanisms of knowledge abstraction and transmission through different levels of aggregation. Traditional approaches have focused on the how routines and capabilities can trigger further learning. In this paper it is argued that a focus on learning events as a way to capture emerging knowledge can provide a better understanding of firms’ learning dynamics. By analysing in-depth interview data regarding design-intensive home furnishing sectors in Italy, we focus on identifying those events that trigger relevant learning experiences. By ‘relevant’ we refer here to those events that express a coherent sequence of activities enabling the articulation of new product development-related knowledge. The findings yield an understanding of how a knowledgeintensive activity like design that cuts across a firm’s organisational structure fosters the emergence of capabilities, which originate from one-off solutions for a particular problem and can be further replicated to solve other types of problems.Peer reviewe

The evolutionary dynamics underlying the emergence and development of design as a business function

Trabajo presentado al DRUID Society Conference on Innovation, Startegy and structure - Organizations, Institutions, Systems and Regions celebrado en Copenhagen (Dinamarca) del 15 al 17 de junio de 2011.Despite broad consensus that ´design´ escapes easy categorisations few studies tackle the question of how design practices become embedded within the portfolio of firms’ activities and how they bear upon decision-making. This is relevant because the domain of influence of design activities potentially cuts across the whole organisational spectrum thereby suggesting significant organisational and strategic consequences. The objective of this paper is to analyse critically the ascent of design activities from being relatively peripheral to becoming a key asset for competitive strategy. It will do so by exploring the interdependencies between processes of knowledge creation and systematisation and the division of labour. The case of the furniture sector in Italy will support our argument by illustrating the extent to which technological developments in the 20th century contributed to the progressive emergence of design as driving force for firms’ innovation strategies.Peer Reviewe

Knowledge systematisation, reconfiguration and the organisation of firms and industry: The case of design

The paper explores two pathways that are crucial for making knowledge economically useful knowledge systematisation and knowledge reconfiguration and analyses how their interplay enables the emergence of a new business function or activity. Knowledge systematisation is the abstraction and diffusion of operative principles to the effect of expanding to broader remits practices that had been initially conceived for a narrow purpose. Knowledge reconfiguration involves the conversion and formalisation of these novel practices within existing firm and industry organisation. Using the design activity as a lens, and drawing on primary and secondary interviews and archival data on the home furnishing sectors in Italy, our case study articulates the processes that facilitate the abstraction of general rules from novel practices and the changes that are necessary, both within firm and industry organisation, to foster their diffusion.D'ippolito, B.; Miozzo, M.; Consoli, D. (2014). Knowledge systematisation, reconfiguration and the organisation of firms and industry: The case of design. Research Policy. 43(8):1334-1352. doi:10.1016/j.respol.2014.03.013S1334135243