Robust procedures in multiple regression: P-subsets and a computational proposal

A number of robust and diagnostic techniques for the linear regression are in terms of p-dimensional subsets of the original sample. In a sample of size n this leads to consider ⁿ C _p subsets. To reduce the computational burden, a limited number of subsets can be selected by means of a sub-sampling scheme. In this paper we suggest and discuss the use of a Balanced Incomplete Block design plan.     

An Innovative Science Gateway for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is currently building the next generation, ground-based, very high-energy gamma-ray instrumentation. CTA is expected to collect very large datasets (in the order of petabytes) which will have to be stored, managed and processed. This paper presents a graphical user interface built inside a science gateway aiming at providing CTA-users with a common working framework. The gateway is WS-PGRADE/gUSE workflow-oriented and is equipped with a flexible SSO (based on SAML) to control user access for authentication and authorization. An interactive desktop environment is provided, called Astronomical & Physics Cloud Interactive Desktop (ACID). Users are able to exploit the graphical interface as provided natively by the tools included in ACID. A cloud data service shares and synchronizes data files and output results between the user desktop and the science gateway. Our solution is a first attempt towards an ecosystem of new technologies with a high level of flexibility to suit present and future requirements of the CTA community.     

The proton iron-sulfur cluster environment of the [FeFe]-hydrogenase maturation protein HydF from Thermotoga neapolitana

[FeFe]-hydrogenases contain a complex [4Fe–4S]-2Fe cluster (H-cluster) and are able to efficiently reduce protons to H₂. Due to their potential exploitation for renewable energy production biotechnologies, significant efforts have been put into understanding the mechanisms driving the H-cluster assembly, which involves three conserved proteins. Among them, HydF works as scaffold upon which the H-cluster precursor is synthesized and carrier to deliver it to the hydrogenase, resulting in its activation. A FeS cluster binding sequence (CxHx₄₆-₅₃HCxxC) is conserved in all HydF proteins and should in principle provide four ligands to coordinate the Fe atom. However, we found that alternative metal coordination may exist in different HydF proteins and that only the three cysteines are strictly required, whereas the fourth ligand may vary and is, in any case, readily exchangeable. In this work we analyzed by EPR/HYSCORE the FeS cluster proton environment of HydF from Thermotoga neapolitana to determine the possible role of surrounding residues in the non-cysteinyl iron ligation of the protein.     

Complexity analysis of blast-induced vibrations in underground mining:A case study

Blasting in geological bodies is an industrial process acting in an environment characterized by high uncertainties (natural joints,faults,voids,abrupt structural changes),which are transposed into the...     

DTG combustion behaviour of charcoals

In this paper, data are reported for the behaviour of some charcoals during combustion and devolatilization in a thermal analyser.     

An accurate calculation model of solar heat gain through glazed surfaces

A model for the calculation of solar heat gain through glazed surfaces, to be used in the simplified calculation of thermal energy requirements in air-conditioned buildings, is proposed. The model uses the effective absorption coefficient of the indoor environment to take into account that the entering energy is in part absorbed by the surfaces of the cavity and in part is dispersed outwards, through the same glazed surfaces. The effective absorption coefficient is calculated by means of a correlation, and is made to depend on the average absorption coefficient of the internal opaque surfaces of the environment, on the glazed fraction and on the transmission coefficient of diffuse radiation of the glazed system. This coefficient permits a more accurate evaluation of solar heat gain through glazed surfaces, obtained adding: the direct optical contribution, produced by solar radiation absorbed by the indoor environment, the direct secondary contribution, produced by external solar radiation absorbed by the glazed surfaces, the indirect secondary contribution, produced by the absorption of reflected radiation exiting the indoor environment. The model, validated by means of comparisons with the TRNSYS 16 code, was used for the verification of the monthly solar heat gain calculation procedure of EN ISO 13790:2008.     

Fish and food safety: Determination of formaldehyde in 12 fish species by SPME extraction and GC–MS analysis

The formaldehyde (FA) content in different fish products was evaluated using a solid phase microextraction (SPME)-GC–MS method based on fiber derivatisation with pentafluorobenzyl-hydroxyl-amine hydrochloride. LOD and LOQ values of 17 and 28 μg kg⁻¹, respectively were calculated. Fish quality was assessed by the analysis of 12 species (sea-fish, freshwater-fish and crustaceans), revealing variable FA levels. Fresh, deep frozen, canned, boiled and roasted fish were analysed; cooking always produced a decrease in the analyte content. Fish belonging to the Gadidae family were the samples with the highest FA concentration (from 6.4 ± 1.2 mg kg⁻¹ to 293 ± 26 mg kg⁻¹), in four cases out of 14 exceeding the value of 60 mg kg⁻¹ proposed by the Italian Ministry of Health. Storage on ice was also investigated, showing moderate FA production also at temperature around 0 °C. FA contents lower than 22 mg kg⁻¹ were finally found in all the other samples.     

Gas chromatographic–mass spectrometric characterisation of the Italian Protected Designation of Origin “Altamura” bread volatile profile

Dynamic headspace extraction technique coupled to the gas chromatography–mass spectrometry analysis was applied to characterize volatile compounds of both crust and crumb of the Protected Designation of Origin Italian durum wheat sourdough “Altamura” bread. Volatile compounds of crust and crumb were characterized and statistically compared and their relative abundance was also calculated. A total of 89 compounds belonging to different chemical classes were identified in the crust. More abundant compounds detected in the crust were ethanol (20 ± 6%), 2-furfural (14 ± 7%) and 3-methyl-1-butanol (9 ± 5%). A lower number of volatile compounds (74) was identified in crumb, among which ethanol (32 ± 7%), 3-methyl-1-butanol (23 ± 6%) and 3-pentanol (7 ± 3) were the most abundant. The influence of different baking modes (wood- or gas-fired) on volatile compounds, macroscopic appearance and selected physico-chemical parameters (colour and texture) of bread samples were also evaluated.

Samples baked in wood-fired oven showed larger amount of volatile compounds such as furans and aldehydes that could positively influence the flavour of the product.

Crust of wood-fired breads showed higher amounts of compounds from Maillard reaction, resulting in harder and browner breads than gas-fired samples. Macroscopic appearance of crumb of wood-fired breads showed higher percentages of larger pores, being also less hard and cohesive than gas-fired samples.