Sugarbeet Production Under Reduced Tillage Prospects And Problems

A study was initiated in the fall of 1977 to obtain base line data on the applicability of reduced tillage sugarbeet production in the Red River Valley. Three reduced tillage systems were compared to a conventional system which consisted of fall plow plus secondary tillage. Results indicated warmer early spring soil temperatures, better seedling emergence, lower ground-level wind speed and no significant yield loss under reduced tillage as compared to the conventional system

Study of fuel cells using storable rocket propellants Final report, 18 Aug. 1965 - 23 Jun. 1969

Operating fuel cells on gaseous nitrogen tetroxide and aerozine 5

The environmental security debate and its significance for climate change

Policymakers, military strategists and academics all increasingly hail climate change as a security issue. This article revisits the (comparatively) long-standing “environmental security debate” and asks what lessons that earlier debate holds for the push towards making climate change a security issue. Two important claims are made. First, the emerging climate security debate is in many ways a re-run of the earlier dispute. It features many of the same proponents and many of the same disagreements. These disagreements concern, amongst other things, the nature of the threat, the referent object of security and the appropriate policy responses. Second, given its many different interpretations, from an environmentalist perspective, securitisation of the climate is not necessarily a positive development

Restricting digital sites of dissent: commercial social media and free expression

The widespread use of commercial social media platforms by protesters and activists has enhanced protest mobilisation and reporting but it has placed social media providers in the intermediary role as facilitators of dissent and has thereby created new challenges. Companies like Google and Facebook are increasingly restricting content that is published on or distributed through their platforms; they have been subject to obstruction by governments; and their services have been at the core of large-scale data collection and surveillance. This article analyses and categorises forms of infrastructure-based restrictions on free expression and dissent. It shows how private intermediaries have been incorporated into state-led content policies; how they set their own standards for legitimate online communication and intervene accordingly; and how state-based actions and commercial self-regulation intersect in the specific area of online surveillance. Based on a broad review of cases, it situates the role of social media in the wider trend of the privatisation of communications policy and the complex interplay between state-based regulation and commercial rule-making

Phosphodiesterase-5 inhibitors have distinct effects on the hemodynamics of the liver

<p>Abstract</p> <p>Background</p> <p>The NO - cGMP system plays a key role in the regulation of sinusoidal tonus and liver blood flow with phosphodiesterase-5 (PDE-5) terminating the dilatory action of cGMP. We, therefore, investigated the effects of PDE-5 inhibitors on hepatic and systemic hemodynamics in rats.</p> <p>Methods</p> <p>Hemodynamic parameters were monitored for 60 min. after intravenous injection of sildenafil and vardenafil [1, 10 and 100 μg/kg (sil1, sil10, sil100, var1, var10, var100)] in anesthetized rats.</p> <p>Results</p> <p>Cardiac output and heart rate remained constant. After a short dip, mean arterial blood pressure again increased. Systemic vascular resistance transiently decreased slightly. Changes in hepatic hemodynamic parameters started after few minutes and continued for at least 60 min. Portal (var10 -31%, sil10 -34%) and hepatic arterial resistance (var10 -30%, sil10 -32%) decreased significantly (p < 0.05). At the same time portal venous (var10 +29%, sil10 +24%), hepatic arterial (var10 +34%, sil10 +48%), and hepatic parenchymal blood flow (var10 +15%, sil10 +15%) increased significantly (p < 0.05). The fractional liver blood flow (total liver flow/cardiac output) increased significantly (var10 26%, sil10 23%). Portal pressure remained constant or tended to decrease. 10 μg/kg was the most effective dose for both PDE-5 inhibitors.</p> <p>Conclusion</p> <p>Low doses of phosphodiesterase-5 inhibitors have distinct effects on hepatic hemodynamic parameters. Their therapeutic use in portal hypertension should therefore be evaluated.</p

The Digitalization of Russian Politics and Political Participation

Peer reviewe

Next Generation Cryptographic Ransomware

We are assisting at an evolution in the ecosystem of cryptoware - the malware that encrypts files and makes them unavailable unless the victim pays up. New variants are taking the place once dominated by older versions; incident reports suggest that forthcoming ransomware will be more sophisticated, disruptive, and targeted. Can we anticipate how such future generations of ransomware will work in order to start planning on how to stop them? We argue that among them there will be some which will try to defeat current anti-ransomware; thus, we can speculate over their working principle by studying the weak points in the strategies that seven of the most advanced anti-ransomware are currently implementing. We support our speculations with experiments, proving at the same time that those weak points are in fact vulnerabilities and that the future ransomware that we have imagined can be effective

Homogeneous search for helium in the atmosphere of 11 gas giant exoplanets with SPIRou

The metastable helium triplet in the near-infrared (10833{\AA}) is among the most important probes of exoplanet atmospheres. It can trace their extended outer layers and constrain mass-loss. We use the near-infrared high-resolution spectropolarimeter SPIRou on the CFHT to search for the spectrally resolved helium triplet in the atmospheres of eleven exoplanets, ranging from warm mini-Neptunes to hot Jupiters and orbiting G, K, and M dwarfs. Observations were obtained as part of the SPIRou Legacy Survey and complementary open-time programs. We apply a homogeneous data reduction to all datasets and set constraints on the presence of metastable helium, despite the presence of systematics in the data. We confirm published detections for HAT-P-11b, HD189733b, and WASP-69b and set upper limits for the other planets. We apply the p-winds open source code to set upper limits on the mass-loss rate for the non-detections and to constrain the thermosphere temperature, mass-loss rate, line-of-sight velocity, and the altitude of the thermosphere for the detections. We confirm that the presence of metastable helium correlates with the stellar mass and the XUV flux received by the planets. We investigated the correlation between the mass-loss rate and the presence of metastable helium, but it remains difficult to draw definitive conclusions. Finally, some of our results are in contradiction with previous results in the literature, therefore we stress the importance of repeatable, homogeneous, and larger-scale analyses of the helium triplet to obtain robust statistics, study temporal variability, and better understand how the helium triplet can be used to explore the evolution of exoplanets.Comment: 28 pages, 13 figures, Accepted in A&A for publicatio

A genealogy of hacking

Hacking is now a widely discussed and known phenomenon, but remains difficult to define and empirically identify because it has come to refer to many different, sometimes incompatible, material practices. This paper proposes genealogy as a framework for understanding hacking by briefly revisiting Foucault’s concept of genealogy and interpreting its perspectival stance through the feminist materialist concept of the situated observer. Using genealogy as a theoretical frame a history of hacking will be proposed in four phases. The first phase is the ‘pre-history’ of hacking in which four core practices were developed. The second phase is the ‘golden age of cracking’ in which hacking becomes a self-conscious identity and community and is for many identified with breaking into computers, even while non-cracking practices such as free software mature. The third phase sees hacking divide into a number of new practices even while old practices continue, including the rise of serious cybercrime, hacktivism, the division of Open Source and Free Software and hacking as an ethic of business and work. The final phase sees broad consciousness of state-sponsored hacking, the re-rise of hardware hacking in maker labs and hack spaces and the diffusion of hacking into a broad ‘clever’ practice. In conclusion it will be argued that hacking consists across all the practices surveyed of an interrogation of the rationality of information techno-cultures enacted by each hacker practice situating itself within a particular techno-culture and then using that techno-culture to change itself, both in changing potential actions that can be taken and changing the nature of the techno-culture itself