Nitrogen, science, and environmental change: the politics of the Green Revolution in Chile and the global nitrogen challenge

Abstract The widespread use of nitrogen (N) fertilizers during the second half of the 20th century radically transformed agricultural production and ecosystems on a global scale. Although the "N challenge" or the "N problem" has had limited public attention compared to biodiversity loss and climate change, scientists consider N pollution a leading ecological concern for the 21st century. Accordingly, a major challenge for scientists and policymakers around the world today is how to meet food production demands while also protecting the environment. Using Chile as a case study—one of the highest consumers of N fertilizer per hectare in the Americas—this article examines the transnational politics of production and destruction in this process of agricultural modernization. In the Cold War context, a transnational network of scientists, agencies, and authorities created an institutional framework for the transference of knowledge and technology in Chile during the 1960s. Paradoxically, as local and global reliance on N fertilizers increased, scientists were able to generate a narrative about the negative environmental effects of intensive N use and highlight the ecological limits of the Green Revolution. After 1973, however, this knowledge network suffered as a result of the Chilean government's anti-communist crackdown and adoption of market-based agricultural policies. Understanding this history of how politics shaped N consumption, science, and policy is critical to current efforts to create new of agricultural production on a regional and global scale. Keywords: nitrogen, fertilizers, the Green Revolution, Cold War, Chile, science, environment, policy, Global Nitrogen Challenge, agriculture, United State

The role of ArlRS and VraSR in regulating ceftaroline hypersusceptibility in methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus infections are a global health problem. New control strategies, including fifth-generation cephalosporins such as ceftaroline, have been developed, however rare sporadic resistance has been reported. Our study aimed to determine whether disruption of two-component environmental signal systems detectably led to enhanced susceptibility to ceftaroline in S. aureus CA-MRSA strain MW2 at sub-MIC concentrations where cells normally continue to grow. A collection of sequential mutants in all fifteen S. aureus non-essential two-component systems (TCS) was first screened for ceftaroline sub-MIC susceptibility, using the spot population analysis profile method. We discovered a role for both ArlRS and VraSR TCS as determinants responsible for MW2 survival in the presence of sub-MIC ceftaroline. Subsequent analysis showed that dual disruption of both arlRS and vraSR resulted in a very strong ceftaroline hypersensitivity phenotype. Genetic complementation analysis confirmed these results and further revealed that arlRS and vraSR likely regulate some common pathway(s) yet to be determined. Our study shows that S. aureus uses particular TCS environmental sensing systems for this type of defense and illustrates the proof of principle that if these TCS were inhibited, the efficacy of certain antibiotics might be considerably enhanced.This work was supported by the Swiss National Science Foundation grants (AR 310030-169404), (WLK 10030-146540 and 10030-192784). MV was supported by FNS (Fonds National Suisse) through project funding 10030-146540. The funders had no role in study design, data collection, and interpretation or the decision to submit the work for publication

Relatively compatible operations in BCK-algebras and some related algebras

Let A be a BCK-algebra and f : Ak → A a function. The main goal of this paper is to give a necessary and sufficient condition for ƒ to be compatible with respect to every relative congruence of A. We extend this result in some related algebras, as for example in pocrims.Facultad de Ciencias Exacta

An Experimental Approach to Vibro-Acoustic Study of Beam-Type Structures

In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method-FEM, showing a good agreement

First survey of centimeter-scale AC-LGAD strip sensors with a 120 GeV proton beam

We present the first beam test results with centimeter-scale AC-LGAD strip sensors, using the Fermilab Test Beam Facility and sensors manufactured by the Brookhaven National Laboratory. Sensors of this type are envisioned for applications that require large-area precision 4D tracking coverage with economical channel counts, including timing layers for the Electron Ion Collider (EIC), and space-based particle experiments. A survey of sensor designs is presented, with the aim of optimizing the electrode geometry for spatial resolution and timing performance. Several design considerations are discussed towards maintaining desirable signal characteristics with increasingly larger electrodes. The resolutions obtained with several prototypes are presented, reaching simultaneous 18 micron and 32 ps resolutions from strips of 1 cm length and 500 micron pitch. With only slight modifications, these sensors would be ideal candidates for a 4D timing layer at the EIC

EFFECT OF SUPPLEMENTATION OF A PROBIOTIC STRAIN ON THE PRODUCTIVE PERFORMANCE OF THE GUINEA PIG (CAVIA PORCELLUS)

El objetivo del presente estudio fue evaluar el efecto de la suplementación de una cepa probiótica aislada de la microbiota intestinal del cuy sobre sus parámetros productivos.Se utilizaron 80 cuyes machos desde el primer día de edad, distribuidos en 40 unidades experimentales. Se emplearon cinco tratamientos con ocho repeticiones por tratamiento: T1, T2 y T3 recibieron 100, 150 y 200 ml de probiótico, respectivamente, y T4 y T5 fueron los controles positivo y negativo, respectivamente. Se evaluó el consumo de materia seca, ganancia de peso, índice de conversión alimenticia (ICA) y rendimiento de carcasa. T2 presentó el menor consumo de materia seca (2564 g) y el menor ICA (3.90) y T5 el mayor consumo (3293 g) y el mayor ICA (5.04). La ganancia de peso y el peso y rendimiento de carcasa no se vieron afectados por el probiótico. La inclusión en la dieta de cepas probióticas provenientes de la microbiota intestinal del cuy afectó (p<0.05) el índice de conversión alimenticia en la etapa de crecimiento y engorde de cuyes.The aim of this study was to evaluate the effect of supplementing a probiotic strainisolated from guinea pig intestinal microbiota on its performance during the growing andfattening period. A total of 80 male guinea pigs of one day old were distributed in 40experimental units. Five treatments with eight replicates per treatment were used: T1, T2,and T3 received 100, 150 and 200 ml of probiotic respectively, and T4 y T5 were thepositive and negative controls respectively. Dry matter intake (DMI), body weight gain,feed conversion ratio (FCR) and carcass yield were evaluated. T2 showed the lowestDMI (2564 g) and FCR (3.90) whereas T5 had the highest DMI (3293 g) and FCR (5.04).Body weight gain and weight and carcass yield were not affected by the probiotic. Thedietary inclusion of probiotic strains from guinea pig intestinal microbiota significantlyaffect (p<0.05) feed conversion ratio in growing and fattening guinea pigs

Characterization of BNL and HPK AC-LGAD sensors with a 120 GeV proton beam

We present measurements of AC-LGADs performed at the Fermilab's test beam facility using 120 GeV protons. We studied the performance of various strip and pad AC-LGAD sensors that were produced by BNL and HPK. The measurements are performed with our upgraded test beam setup that utilizes a high precision telescope tracker, and a simultaneous readout of up to 7 channels per sensor, which allows detailed studies of signal sharing characteristics. These measurements allow us to assess the differences in designs between different manufacturers, and optimize them based on experimental performance. We then study several reconstruction algorithms to optimize position and time resolutions that utilize the signal sharing properties of each sensor. We present a world's first demonstration of silicon sensors in a test beam that simultaneously achieve better than 6-10 micron position and 30 ps time resolution. This represents a substantial improvement to the spatial resolution than would be obtained with binary readout of sensors with similar pitch

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele