Diversifying crop rotations for sustainable production and climate change adaptation

Industrial cropping systems are increasingly simplified, with fewer crops being grown, requiring extensive use of inputs, and contributing to environmental pollution and climate change. Solutions are needed to reduce the negative effects, while retaining productivity in the face of increasingly frequent detrimental climatic conditions. Crop rotational diversity has shown promises to increase staple cereal yields, especially under low fertilisation regimes and years of low productivity. However, it is unclear how different levels and types of crop rotational diversity mediate the interaction between productivity, contrasting levels of fertilisation, and explicit climatic conditions. Moreover, crop diversification substitutes staple cereals with alternative crop types, e.g., legumes, broadleaves, and perennial mixtures of grasses and legumes, raising the question whether sufficient and sufficiently nutritious food can be produced with less nitrogen inputs in diverse rotations. Using data from 32 long-term field experiments (10-64 years) from Europe and North America, I show that crop rotational diversity, expressed as species diversity or functional richness, enhances cereal yields over time, particularly under regimes of low fertilisation. I also show that crop rotational diversity can reduce cereal yield losses caused by detrimental climatic conditions. Using a sub-set of the European data, I also show that increasing functional richness can increase the outputs of human-available calories and macronutrients, i.e., carbohydrates, proteins, and fats, with increasing benefits over time, and requiring less nitrogen than cereal-only rotations. In summary, crop rotational diversity can benefit food security and sustainability, and provide climate adaptation to cropping systems

An Inkjet Printed Chipless RFID Sensor for Wireless Humidity Monitoring

A novel chipless RFID humidity sensor based on a finite Artificial Impedance Surface (AIS) is presented. The unit cell of the AIS is composed of three concentric loops thus obtaining three deep and high Q nulls in the electromagnetic response of the tag. The wireless sensor is fabricated using low-cost inkjet printing technology on a thin sheet of commercial coated paper. The patterned surface is placed on a metal backed cardboard layer. The relative humidity information is encoded in the frequency shift of the resonance peaks. Varying the relative humidity level from 50% to 90%, the frequency shift has proven to be up to 270MHz. The position of the resonance peaks has been correlated to the relative humidity level of the environment on the basis of a high number of measurements performed in a climatic chamber, specifically designed for RF measurements of the sensor. A very low error probability of the proposed sensor is demonstrated when the device is used with a 10% RH humidity level discrimination

Android Permissions Unleashed

The Android Security Framework controls the executions of applications through permissions which are statically granted by the user during installation. However, the definition of security policies over permissions is not supported. Security policies must be therefore manually encoded into the application by the developer, which is a dangerous practice and may cause security breaches. We propose an improvement over the Android permission system that supports the specification and enforcement of fine-grained security policies. Enforcement is achieved by reducing policy decision problems to propositional satisfiability and leveraging a state-of-the-art SAT solver. Unlike alternative proposals, our approach does not require changes in the operating system and, therefore, it can be readily deployed in any commercial device

Soliton Turbulence in Shallow Water Ocean Surface Waves

We analyze shallow water wind waves in Currituck Sound, North Carolina and experimentally confirm, for the first time, the presence of $soliton$ $turbulence$ in ocean waves. Soliton turbulence is an exotic form of nonlinear wave motion where low frequency energy may also be viewed as a $dense$ $soliton$ $gas$, described theoretically by the soliton limit of the Korteweg-deVries (KdV) equation, a $completely$ $integrable$ $soliton$ $system$: Hence the phrase "soliton turbulence" is synonymous with "integrable soliton turbulence." For periodic/quasiperiodic boundary conditions the $ergodic$ $solutions$ of KdV are exactly solvable by $finite$ $gap$ $theory$ (FGT), the basis of our data analysis. We find that large amplitude measured wave trains near the energetic peak of a storm have low frequency power spectra that behave as $\sim\omega^{-1}$. We use the linear Fourier transform to estimate this power law from the power spectrum and to filter $densely$ $packed$ $soliton$ $wave$ $trains$ from the data. We apply FGT to determine the $soliton$ $spectrum$ and find that the low frequency $\sim\omega^{-1}$ region is $soliton$ $dominated$. The solitons have $random$ $FGT$ $phases$, a $soliton$ $random$ $phase$ $approximation$, which supports our interpretation of the data as soliton turbulence. From the $probability$ $density$ $of$ $the$ $solitons$ we are able to demonstrate that the solitons are $dense$ $in$ $time$ and $highly$ $non$ $Gaussian$.Comment: 4 pages, 7 figure

A Nonparametric Estimator for Coherent Change Detection: The Permutational Change Detection

Nowadays, synthetic aperture radar (SAR) is widely used in heterogeneous fields with aims strictly dependent on the objectives of the application. One of the most common is the exploitation of the interferometric-SAR (InSAR) to measure millimeter movements on the Earth's surface, aiming to monitor failures (e.g., landslides) or to measure the health state of infrastructures (e.g., mining assets, bridges, and buildings). In this article, developing algorithms to detect temporal and spatial changes in the radar targets becomes very important. This article focuses on the temporal change detection framework, proposing a nonparametric coherent change detection (CCD) algorithm called permutational change detection (PCD), a purely statistical algorithm whose core is the permutational test. The PCD estimates the temporal change points (CPs) of a radar target recognizing blocks structure in the coherence matrix, namely, new radar objects. The algorithm has been fine-tuned for small SAR datasets, with the specific aim of prioritizing the analysis of the latest changes. A rigorous mathematical derivation of the algorithm is carried out, explaining how some limits have been addressed. Then, the performance analysis on the simulated data is deeply accomplished, carried out for the stand-alone PCD and the PCD compared with a parametric CCD algorithm based on the generalized likelihood ratio test (GLRT), and with the Omnibus and REACTIV detectors. The comparison with these other algorithms and the stand-alone performance analysis point out the robustness of the PCD in dealing with very noisy environments, even in the case of a single block. Finally, the PCD is validated by processing two Sentinel I data stacks, ascending and descending geometries, of the 2016 Central Italy earthquake

Accelerated carbonation of steel slags using CO2 diluted sources: CO2 uptakes and energy requirements

This work presents the results of carbonation experiments performed on Basic Oxygen Furnace (BOF) steel slag samples employing gas mixtures containing 40 and 10% CO2 vol. simulating the gaseous effluents of gasification and combustion processes respectively, as well as 100% CO2 for comparison purposes. Two routes were tested, the slurry-phase (L/S = 5 l/kg, T = 100°C and Ptot = 10 bar) and the thin-film (L/S = 0.3–0.4 l kg, T = 50°C and Ptot = 7–10 bar) routes. For each one, the CO2 uptake achieved as a function of the reaction time was analyzed and on this basis, the energy requirements associated with each carbonation route and gas mixture composition were estimated considering to store the CO2 emissions of a medium size natural gas fired power plant (20 MW). For the slurry-phase route, maximum CO2 uptakes ranged from around 8% at 10% CO2, to 21.1% (BOF-a) and 29.2% (BOF-b) at 40% CO2 and 32.5% (BOF-a) and 40.3% (BOF-b) at 100% CO2. For the thin-film route, maximum uptakes of 13% (BOF-c) and 19.5% (BOF-d) at 40% CO2, and 17.8% (BOF-c) and 20.2% (BOF-d) at 100% were attained. The energy requirements of the two analyzed process routes appeared to depend chiefly on the CO2 uptake of the slag. For both process route, the minimum overall energy requirements were found for the tests with 40% CO2 flows (i.e., 1400−1600 MJ/tCO2 for the slurry-phase and 2220 – 2550 MJ/tCO2 for the thin-film route)

Crop rotational diversity can mitigate climate-induced grain yield losses

Diversified crop rotations have been suggested to reduce grain yield losses from the adverse climatic conditions increasingly common under climate change. Nevertheless, the potential for climate change adaptation of different crop rotational diversity (CRD) remains undetermined. We quantified how climatic conditions affect small grain and maize yields under different CRDs in 32 long-term (10-63 years) field experiments across Europe and North America. Species-diverse and functionally rich rotations more than compensated yield losses from anomalous warm conditions, long and warm dry spells, as well as from anomalous wet (for small grains) or dry (for maize) conditions. Adding a single functional group or crop species to monocultures counteracted yield losses from substantial changes in climatic conditions. The benefits of a further increase in CRD are comparable with those of improved climatic conditions. For instance, the maize yield benefits of adding three crop species to monocultures under detrimental climatic conditions exceeded the average yield of monocultures by up to 553 kg/ha under non-detrimental climatic conditions. Increased crop functional richness improved yields under high temperature, irrespective of precipitation. Conversely, yield benefits peaked at between two and four crop species in the rotation, depending on climatic conditions and crop, and declined at higher species diversity. Thus, crop species diversity could be adjusted to maximize yield benefits. Diversifying rotations with functionally distinct crops is an adaptation of cropping systems to global warming and changes in precipitation.Industrial agriculture often relies on one or few crop species grown in monocultures or short crop rotations, making them vulnerable to changes in climatic conditions. Using data from several agricultural experiments in Europe and North America, we show that including more crop species or crop types in rotation can mitigate cereal yield losses caused by increasingly common shifts in climatic conditions, such as increasing temperatures and decreasing precipitation. Hence, increasing crop rotational diversity can support the climate adaptation of the way we produce our food.imag

O educador em seu ‘quefazer’ ambiental: uma análise a partir da dialética materialista

Este texto tem como objetivo contribuir para o ‘quefazer’ de educadores ambientais trazendo a proposta da dialética materialista dentro do método marxista que une teoria e prática para a formação do homem em sua totalidade. Pois um processo educativo se define enquanto conseguem apreender, educador e educando, a estrutura da sociedade. Elencamos neste texto, as categorias contradições, movimento e totalidade para uma análise crítica da sociedade determinada pelo sistema capitalista

Indoor channel characterization for future 5G applications

The shortage of frequency band below 6 GHz available for communications and data transfer has recently fostered the interest toward the millimeter wave (mmW) spectrum. In fact, mmW carrier frequencies allow for larger bandwidth allocations thus higher data transfer rates. It is therefore useful to evaluate the channel propagation properties of mmW within an indoor environment. In particular, the statistical parameters such as path loss exponent and shadowing have been examined by using a reliable numerical solver based on a ray-tracing (RT) technique. The results for both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions at 28 GHz and 72 GHz are reported for the case of an office environment