The rise of smart cities and the increasing demand for drones has sparked considerable interest in the Internet of Drones (IoD) within the realms of academia and industry. IoD presents a multitude of ...advantages in smart city settings, facilitating services like traffic monitoring, environmental surveillance, and disaster management by harnessing the potential of IoT and Flying Ad-Hoc Networks (FANET) infrastructures. However, the transmission of sensitive messages between drones in IoD-based smart cities is disseminated over insecure channels, leaving them exposed to security vulnerabilities. Furthermore, drones operating in IoD architectures are prone to physical capture attacks as they operate in unattended environments with minimal human intervention. Moreover, the limited resources of drones pose challenges to the practicality of employing computationally intensive cryptographic methods. In response to these challenges, we introduce PAF-IoD, an authentication framework that prioritizes security and efficiency. PAF-IoD leverages physical unclonable functions (PUFs) and the AEGIS authenticated encryption scheme to guarantee trustworthy and secure communication between users and drones in smart cities. In terms of security validation, we perform both random and real model-based formal analyses. Furthermore, we employ the Scyther tool to ensure the resilience of PAF-IoD against different security vulnerabilities. Additionally, an informal analysis is conducted to demonstrate the resilience of PAF-IoD against various attacks. By introducing PAF-IoD, we offer a secure solution that addresses vulnerabilities and resource limitations associated with drone communication. The proposed framework guarantees the integrity and confidentiality of data while optimizing computational and communication resources, thereby enabling reliable and effective IoD operations in smart cities.
The use of underground ring drilling and blasting holes is common, given their compatibility with various mining methods and use in the construction of underground structures like the ore draw bells. ...Working conditions and rock properties can vary significantly, making it essential to monitor and analyze the blasting results. If necessary, the adjustments and optimizations should be made to the drilling and blasting patterns based on the properties of the used explosives. The aim of this paper is to develop a stopping mining method model using the blastholes, as well as a unique drilling and blasting pattern for excavation the initial slot in the Datamine Aegis. The objective was to compare several types of explosives with different properties in this context, predict the blast outcomes in terms of break radius, and highlight the significance of all explosive parameters in selecting and optimizing a drill and blast ring pattern.
DNA polymerases have evolved for billions of years to accept natural nucleoside triphosphate substrates with high fidelity and to exclude closely related structures, such as the analogous ...ribonucleoside triphosphates. However, polymerases that can accept unnatural nucleoside triphosphates are desired for many applications in biotechnology. The focus of this review is on non-standard nucleotides that expand the genetic alphabet. This review focuses on experiments that, by directed evolution, have created variants of DNA polymerases that are better able to accept unnatural nucleotides. In many cases, an analysis of past evolution of these polymerases (as inferred by examining multiple sequence alignments) can help explain some of the mutations delivered by directed evolution.
Understanding the evolution of carbon and iron in the Milky Way's halo is of importance because these two elements play crucial roles in constraining star formation, Galactic assembly, and chemical ...evolution in the early universe. Here we explore the spatial distributions of the carbonicity, C/Fe, and metallicity, Fe/H, of the halo system based on medium-resolution (R ∼ 1300) spectroscopy of ∼58,000 stars in the southern hemisphere from the AAOmega Evolution of Galactic Structure (AEGIS) survey. The AEGIS carbonicity map exhibits a positive gradient with distance, as similarly found for the Sloan Digital Sky Survey carbonicity map of Lee et al. The metallicity map confirms that Fe/H decreases with distance from the inner halo to the outer halo. We also explore the formation and chemical evolution history of the halo by considering the populations of carbon-enhanced metal-poor (CEMP) stars present in the AEGIS sample. The cumulative and differential frequency of CEMP-no stars (as classified by their characteristically lower levels of absolute carbon abundance, A(C) ≤ 7.1, for subgiants and giants) increases with decreasing metallicity and is substantially higher than previous determinations for CEMP stars as a whole. In contrast, that of CEMP-s stars (with higher A(C)) remains almost flat, at a value of ∼10% in the range −4.0 Fe/H −2.0. The distinctly different behaviors of the CEMP-no and CEMP-s stars relieve the tension with population synthesis models assuming a binary mass-transfer origin, which previously struggled to account for the higher reported frequencies of CEMP stars, taken as a whole, at low metallicity.
This article addresses competing visions of sovereignty that underwrite recent debates about monuments. It turns to a well-known monument built to commemorate the loss of British lives in the Sepoy ...Rebellion of 1857–59: the Kanpur (Cawnpore) Memorial Well Monument. The memorial stood over a well in which the bodies of 200 British women and children killed by Indian sepoys lay buried. A large landscaped enclosure was built around the memorial and only European visitors were given access to the site. On August 15, 1947, the day of Indian independence from British rule, a crowd overran the site and defaced the monument. Much of the monument was subsequently dismantled and moved to a more secluded site within the Kanpur cantonment. The desire among the British stakeholders to leave no trace of its former identity focused attention on those aspects of meaning ascribed to the monument that could not be erased. Building on the Hobbesian idea of passion as a key element of sovereignty, this article argues that the monument may be viewed as an aegis — an apotropaion — that deflects gaze more than it enables attentive looking.
•Competing visions of sovereignty underwrite the recent debates about monuments.•Analysis of the geography of monuments helps us understand sovereignty and its relation to colonialism.•Colonial sovereignty is a constant state of war.•The test of sovereignty resides in its exercise by those who claim to operate under the aegis of sovereignty.•The Kanpur Memorial Well Monument demonstrates the making/unmaking of the aegis that was intended to tackle fear and failure.
To expand the existing genetic letters beyond the natural four nucleotides, such as G, C, A, and T, it is necessary to design robust nucleotides that can not only produce stable and unperturbed DNA ...but also function naturally in living cells. Although hydrophobic bases, such as d5SICS (2,6-dimethyl-2
-isoquiniline-1-thione) and dNaM (2-methoxy-3-methylnaphthalene) were shown to be replicated in bacterial cells, the d5SICS:dNaM base-pair was found to perturb the structure of the duplex DNA. Therefore, it is necessary to design nucleobases that can form base pairs like the natural G:C and A:T pairs. Here, a reliable dispersion-corrected density functional theory has been used to design several nucleobases that can produce three-hydrogen-bonded base pairs like the G:C pair. In doing so, the Watson-Crick faces of d5SICS and dNaM were modified by replacing the hydrophobic groups with hydrogen bond donors and acceptors. As dNaM contains an unnatural
-glycosidic bond (
-dNaM), it was also modified to contain the natural
-glycosidic bond (
-dNaM). This technique produced 91 new bases (
-d5SICS-X (
= 1-33),
-dNaM-X (
= 1-35), and
-dNaM-X (
= 1-23), where
is the different types of modifications applied to d5SICS and dNaM) and 259 base-pairs. Among these base pairs, 76 base pairs are found to be more stable than the G:C pair. Interestingly, the
-d5SICS-32:
-dNaM-32 and
-d5SICS-32:
-dNaM-20 pairs are found to be the most stable with binding energies of about -28.0 kcal/mol. The base-pair patterns of these pairs are also analogous to that of the G:C pair. Hence, it is proposed that
-d5SICS-32,
-dNaM-32, and
-dNaM-20 would act as efficient new genetic letters to produce stable and unperturbed artificial DNA.Communicated by Ramaswamy H. Sarma.
Intellectual property protection mechanisms (IPPMs) are critical to fostering science, technology, and innovation, and their relevance has grown enormously with the increased trade in goods and ...services involving patentable technologies. Scholars have investigated factors that facilitate or hinder the use of such IP protection strategies by identifying related country, sector, and firm characteristics. However, the extant literature has overlooked the role of the characteristics of a firm’s founding team on the choice of an IPPM strategy. Using data from a large cross-sectional sample of European small, young, and innovative firms, we show that controlling for firm size, R&D intensity, and other firm and market effects, founding team characteristics, such as gender and education, greatly influence the choice of a strategy. In particular, in line with the general finding that women patent less, we find that firms with more women in the founding team patent less than firms with more male founders; but contrary to the literature that has primarily focused on large firms, we find that as the number of female founders increases, small, young entrepreneurial firms tend to use less informal IPPMs rather than formal IPPMs. We also find, within the context of entrepreneurship policy, that the education and
not experience
of founding team members is a main predictor of IP adoption.
The recent outbreak of the SARS-CoV-2 infection has affected the lives and economy of more than 200 countries. The unavailability of virus-specific drugs has created an opportunity to identify ...potential therapeutic agents that can control the rapid transmission of this pandemic. Here, the mechanisms of the inhibition of the RNA-dependent RNA polymerase (RdRp), responsible for the replication of the virus in host cells, are examined by different ligands, such as Remdesivir (RDV), Remdesivir monophosphate (RMP), and several artificially expanded genetic information systems (AEGISs) including their different sequences by employing molecular docking, MD simulations, and MM/GBSA techniques. It is found that the binding of RDV to RdRp may block the RNA binding site. However, RMP would acquire a partially flipped conformation and may allow the viral RNA to enter into the binding site. The internal dynamics of RNA and RdRp may help RMP to regain its original position, where it may inhibit the RNA-chain elongation reaction. Remarkably, AEGISs are found to obstruct the binding site of RNA. It is shown that dPdZ, a two-nucleotide sequence containing P and Z would bind to RdRp very strongly and may occupy the positions of two nucleotides in the RNA strand, thereby denying access of the substrate-binding site to the viral RNA. Thus, it is proposed that the AEGISs may act as novel therapeutic candidates against the SARS-CoV-2. However, in vivo evaluations of their potencies and toxicities are needed before using them against COVID-19.
Communicated by Ramaswamy H. Sarma
AEGIS nucleotides can act as potent inhibitors of the RdRp by denying the access of the viral RNA to the replicative polymerase.
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