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Saved by the Rook: A case of matchings and hamiltonian cycles
No full textThe rook graph is a graph whose edges represent all the possible legal moves of the rook chess piece on a chessboard. The problem we consider is the following. Given any set M containing pairs of cells such that each cell of the m1×m2 chessboard is in exactly one pair, we determine the values of the positive integers m1 and m2 for which it is possible to construct a closed tour of all the cells of the chessboard which uses all the pairs of cells in M and some edges of the rook graph. This is an alternative formulation of a graph-theoretical problem presented in [Electron. J. Combin. 28(1) (2021), #P1.7] involving the Cartesian product G of two complete graphs Km1 and Km2, which is, in fact, isomorphic to the m1 × m2 rook graph. The problem revolves around determining the values of the parameters m1 and m2 that would allow any perfect matching of the complete graph on the same vertex set of G to be extended to a Hamiltonian cycle by using only edges in G
Special properties of transonic flows in a channel with a lenticular bump
Full text linkThe present study focuses on particular properties of transonic flows through a planar channel featuring a circular bump on the lower wall. The selected geometry is reminiscent of the region surrounding the trailing edge of an airfoil at zero angle of attack and the resulting flow pattern is indeed similar to the fishtail shock-pattern that characterizes airfoils flying at nearly sonic speed. Numerical simulations have been conducted by solving the inviscid Euler equations using both a
commercial and an in-house CFD code; discontinuities are modeled using shock-capturing in the former and shock-fitting in the latter. Numerical experiments reveal different shock-patterns obtained by independently varying the inlet Mach number and the outlet-to-inlet static pressure ratio. When shock-interactions occur, shock-polar analysis reveals that the branching point can be modeled using either von Neumann’s three-shock-theory or Guderley’s four-wave-theory, depending on the inlet
Mach number. Furthermore, for certain pairs of boundary conditions, multiple solutions have been observed
Soil organic matter quality in an olive orchard differently managed for 21 years: Insights into its distribution through soil aggregates and depth
No full textAmong the current global challenges, the research of new practices aimed at mitigating soil impoverishment, exacerbated by the pressing climate changes, is the most urgent. Studying soil organic matter (SOM) ecological dynamics and comparing the conventional intensive farming practices with the emerging alternative sustainable ones can represent a key indicator in soil health investigation, helping to find new guidelines for conservative agrosystems management. In this study, the soil from a Mediterranean olive orchard, with both sustainable (Smng) and conventional (Cmng) land use for 21 years, was investigated for its physicochemical properties, with a particular attention to the soil organic matter from aggregates (SOM-A) and its interaction and distribution at different soil depths. Significantly higher amounts of total carbon (+50.7 %) and nitrogen (+74.9 %), as well as of SOM-A aromatic component (+76.0 %), were detected in the topsoil layer (0–5 cm) of the Smng, compared to the Cmng, a sign that the organic matter from surface deeply seeps slowly. This evidence was highlighted espe-cially in micro-aggregates (< 0.063 mm) of the Smng, compared to the Cmng (C = +59.3 %; N = +86.7 %; SOM-A aromatic component = +87.7 % in the Smng). This trend was also reflected in an increase in the bacterial abundance and in a different accumulation of organic compounds deriving from microbial fermentation pro-cesses in Smng soil, as highlighted by the SOM-A qualitative characterization by metabolomics. The soil miner-alogical analysis showed that minerals maintained a higher crystallinity in the Smng than in the Cmng, where soil tillage promoted their alteration. Moreover, Fourier-transform infrared (FTIR) spectroscopy analysis highlighted that soil disturbance in the Cmng can affect SOM distribution, creating different spatial distributions in the particle aggregates and soil depths. Distinguishing SOM quantity, quality, and interaction with mineral com-ponents can help to understand its degradability and dynamics, both essential for mitigating the effects of climate change and promoting land protection
Search for the Higgs boson decays to a ρ0, φ, or K∗0 meson and a photon in proton-proton collisions at √s = 13 TeV
No full textThree rare decay processes of the Higgs boson to a ρ (770)0, φ(1020), or K∗(892)0 me-
son and a photon are searched for using √s = 13 TeV proton-proton collision data col-
lected by the CMS experiment at the LHC. Events are selected assuming the mesons
decay into a pair of charged pions, a pair of charged kaons, or a charged kaon and
pion, respectively. Depending on the Higgs boson production mode, different trigger-
ing and reconstruction techniques are adopted. The analyzed data sets correspond to
integrated luminosities up to 138 fb−1, depending on the reconstructed final state. Af-
ter combining various data sets and categories, no significant excess above the back-
ground expectations is observed. Upper limits at 95% confidence level on the Higgs
boson branching fractions into ρ (770)0γ, φ(1020)γ, and K∗(892)0γ are determined
to be 3.7 × 10−4, 3.0 × 10−4, and 3.0 × 10−4, respectively. In case of the ρ (770)0γ and
φ(1020)γ channels, these are the most stringent experimental limits to date
From Rationalism to Brutalism: An Architectural Heritage to Be Sustainability Transformed. Intervention Strategies
No full textThe landscape of destruction that characterized Europe after World War II prompted architects, first and foremost British architects, to search for a new language that would depart from the sentimentalist language of Neo Empiricism and Neo Realism. In a context marked by a serious social emergency and a strong need for renewal linked to the problem of post-war reconstruction, the architects Alison and Peter Smithson coined the term Brutalism in 1954, an architectural phenomenon destined to spread shortly afterwards to the rest of Europe and America, becoming a true architectural current. Their main intent was to create great works at a reduced cost, bringing out the authenticity of the materials used in construction through a simple and repetitive architecture, made of raw materials, that could receive great approval from society and mark the overcoming of the Modern Movement. Many architects in Italy and around the world in the 1980s—even the most representative ones in terms of public use, size and archi-tectural solemnity—turned to “brutalist” architecture [1] derived from the works of Le Corbusier and later James Stirling, Denys Lasdun, Louis Kahn and Paul Rudolph, and as Zaha Hadid and Tadao Ando continued to do in the buildings of the Vitra Museum in Weil am Rhein until 1993. The extremism of the poetics of béton brut has led to the construction of buildings with perimeter walls and roof ceilings, as well as floors on unheated spaces, lacking thermal insulation, which today are extremely costly to manage, at least when they do not present serious thermo-hygrometric pathologies [2]. The challenge is to identify intervention solutions that achieve the objectives of economic feasibility, energy efficiency and sustainability of the project, while respecting the original architectural configuration, proposing strategies that can be applied in all similar cases
Carbon neutrality and beef production in the marginal areas: A case study of Podolian cattle system
Full text linkCONTEXT
The Sixth Assessment Report of the Intergovernmental Panel on Climate Change stated that human activities caused global warming, mainly through emissions of greenhouse gases (GHGs); livestock supply chains contribute 14.5 % of global anthropogenic GHG emissions, with cattle (beef, milk) accounting for about two-thirds of that total, mainly due to methane emissions resulting from enteric fermentation.
OBJECTIVE
This study aimed to assess the environmental sustainability of the Podolian beef production system in marginal areas of Southern Italy (specifically the Basilicata region) through the Life Cycle Assessment (LCA) approach and identify suitable mitigation strategies.
METHODS
The environmental impact of Podolian beef production was assessed using the following indicators: Global warming potential (GWP100, kg CO2 eq), Freshwater eutrophication (FEP, g P eq), Terrestrial acidification (TAP, g SO2 eq), Marine eutrophication (MEP, g N eq), Land use (LOP, m2 year crop eq), Fossil resource scarcity (FFP, g oil eq), Mineral resource scarcity (SOP, g Cu eq), and Fine particulate matter formation (PMFP, g PM 2.5 eq). The boundaries of the beef production systems encompassed a cradle-to-farm gate analysis. Three functional units (FU) were used: kg of live weight (LW) at slaughter, kg of carcass weight (CW) and hectare of land. Additionally, carbon sequestration from permanent pasture and woodland was calculated.
RESULTS AND CONCLUSIONS
Our case study evaluated the main impact categories of livestock farming for beef production. The results of GWP100 were higher than the European average for the three functional units considered. As the overall outcome is the total deducted the 39 % due to grassland management. Achieving carbon neutrality would require 16.7 ± 4.9 m2 of woodland per kg of LW or 30.8 ± 9.0 m2 of woodland per kg of CW.
SIGNIFICANCE
Our study indicates that the environmental impact per kilogram of beef produced in marginal contexts is generally higher than in intensive livestock farming systems. However, delving deeper into the specific context and accounting for carbon sequestration from pastures used in this cattle farming allows to achieve environmental performance comparable to the most efficient intensive systems. Specifically, we identified the wooded area resource within the Podolian cattle farming system as an existing mitigation strategy which requires effective management and preservation. This study provides more explicit guidance to policymakers and consumers on the environmental implications of different meat production practices, supporting more informed planning of regional, national, and European resources
May the Extensive Farming System of Small Ruminants Be Smart?
No full textPrecision Livestock Farming (PLF) applies a complex of sensor technology, algorithms, and multiple tools for individual, real-time livestock monitoring. In intensive livestock systems, PLF is now quite widespread, allowing for the optimisation of management, thanks to the early recognition of diseases and the possibility of monitoring animals’ feeding and reproductive behaviour, with an overall improvement of their welfare. Similarly, PLF systems represent an opportunity to improve the profitability and sustainability of extensive farming systems, including those of small ruminants, rationalising the use of pastures by avoiding overgrazing and controlling animals. Despite the livestock distribution in several parts of the world, the low profit and the relatively high cost of the devices cause delays in implementing PLF systems in small ruminants compared to those in dairy cows. Applying these tools to animals in extensive systems requires customisation compared to their use in intensive systems. In many cases, the unit prices of sensors for small ruminants are higher than those developed for large animals due to miniaturisation and higher production costs associated with lower production numbers. Sheep and goat farms are often in mountainous and remote areas with poor technological infrastructure and ineffective electricity, telephone, and internet services. Moreover, small ruminant farming is usually associated with advanced age in farmers, contributing to poor local initiatives and delays in PLF implementation. A targeted literature analysis was carried out to identify technologies already applied or at an advanced stage of development for the management of grazing animals, particularly sheep and goats, and their effects on nutrition, production, and animal welfare. The current technological developments include wearable, non-wearable, and network technologies. The review of the technologies involved and the main fields of application can help identify the most suitable systems for managing grazing sheep and goats and contribute to selecting more sustainable and efficient solutions in line with current environmental and welfare concerns