While many books have been written on the naval history of the Revolution, this is one of the first to treat it in its entirety as an Atlantic-wide conflict. While its geographical scope is vast, it ...features overlooked aspects of the war in which sloops and barges fought, actions which proved to be as decisive as the familiar ship of the line confrontations. It is also history from the bottom up, emphasizing the role of the crew as much the not always heroic officers. From naval perspective the rebellious colonies did not gain a military victory, though Benjamin Franklin was able to secure their independence at the peace table in Europe. The final chapter on the Royal Navy's evacuation of white and black loyalists, will be examined in more detail in the author's forthcoming Pen & Sword book.
According to the accepted wisdom in security studies, unmanned aerial vehicles, also known as drones, have revolutionizing effects on war and world politics. Drones allegedly tilt the military ...balance in favor of the offense, reduce existing asymmetries in military power between major and minor actors, and eliminate close combat from modern battlefields. A new theory about the hider-finder competition between air penetration and air defense shows that drones are vulnerable to air defenses and electronic warfare systems, and that they require support from other force structure assets to be effective. This competition imposes high costs on those who fail to master the set of tactics, techniques, procedures, technologies, and capabilities necessary to limit exposure to enemy fire and to detect enemy targets. Three conflicts that featured extensive employment of drones—the Western Libya military campaign of the second Libyan civil war (2019–2020), the Syrian civil war
(2011–2021), and the Armenia-Azerbaijan conflict over Nagorno-Karabakh (2020)—probe the mechanisms of the theory. Drones do not by themselves produce the revolutionary effects that many have attributed to them.
With the growing use of underwater acoustic communications (UWAC) for both industrial and military operations, there is a need to ensure communication security. A particular challenge is represented ...by underwater acoustic networks (UWANs), which are often left unattended over long periods of time. Currently, due to the physical and performance limitations, the UWAC packets rarely include encryption, leaving the UWAN exposed to external attacks faking legitimate messages. In this paper, we propose a new algorithm for message authentication in a UWAN setting. We begin by observing that, due to the strong spatial dependency of the underwater acoustic channel, an attacker can attempt to mimic the channel associated with the legitimate transmitter only for a small set of receivers, typically just for a single one. Taking this into account, our scheme relies on trusted nodes that independently help a sink node in the authentication process. For each incoming packet, the sink fuses beliefs evaluated by the trusted nodes to reach an authentication decision. These beliefs are based on the estimated statistics of the channel parameters, which are chosen to be the most sensitive to the transmitter-receiver displacement. Our simulation results show accurate identification of an attacker's packet. We also report results from a sea experiment demonstrating the effectiveness of our approach.
Drones have expanded from military operations to performing a broad range of civilian applications. As drone usage increases, humans will interact with such systems more often, therefore, it is ...important to achieve a natural human-drone interaction. Although some knowledge can be derived from the field of human-robot interaction, drones can fly in a 3D space, which essentially changes how humans can interact with them, making human-drone interaction a field of its own. This paper is the first survey on the emerging field of human-drone interaction focusing on multi-rotor systems, providing an overview of existing literature and the current state of the art in the field. This work begins with an analysis and comparison of the drone models that are commonly used by end-users and researchers in the field of human-drone interaction. Following, the current state of the field is discussed, including the roles of humans in HDI, innovative control methods, remaining aspects of interaction, and novelty drone prototypes and applications. This paper concludes by presenting a discussion of current challenges and future work in the field of human-drone interaction.
This paper aims to be an overview of the scientific approach on the development of an inventory of operational stress assessment, specific to the military operations theatre, in order to make it ...available to practicing psychologists. Conclusive scientific data and evidence have been obtained from empirical studies over several years, and the resulting tool can be used with confidence.
Strenuous physical activity promotes inflammation and depletes muscle glycogen, which may increase the iron regulatory hormone hepcidin. Hepcidin reduces dietary iron absorption and may contribute to ...declines in iron status frequently observed following strenuous physical activity.
To determine the effects of strenuous physical activity on hepcidin and dietary iron absorption and whether energy deficit compared with energy balance modifies those effects.
This was a randomized, cross-over, controlled-feeding trial in healthy male subjects (n = 10, mean ± SD age: 22.4 ± 5.4 y, weight: 87.3 ± 10.9 kg) with sufficient iron status (serum ferritin 77.0 ± 36.7 ng/mL). Rest measurements were collected before participants began a 72-h simulated sustained military operation (SUSOPS), designed to elicit high energy expenditure, glycogen depletion, and inflammation, followed by a 7-d recovery period. Two 72-h SUSOPS trials were performed where participants were randomly assigned to consume either energy matched (±10%) to their individual estimated total daily energy expenditure (BAL) or energy at 45% of total daily energy expenditure to induce energy deficit (DEF). On the rest day and at the completion of BAL and DEF, participants consumed a beverage containing 3.8 mg of a stable iron isotope, and plasma isotope appearance was measured over 6 h.
Muscle glycogen declined during DEF and was preserved during BAL (−188 ± 179 mmol/kg, P-adjusted < 0.01). Despite similar increases in interleukin-6, plasma hepcidin increased during DEF but not BAL, such that hepcidin was 108% greater during DEF compared with BAL (7.8 ± 12.2 ng/mL, P-adjusted < 0.0001). Peak plasma isotope appearance at 120 min was 74% lower with DEF (59 ± 38% change from 0 min) and 49% lower with BAL (117 ± 81%) compared with rest (230 ± 97%, P-adjusted < 0.01 for all comparisons).
Strenuous physical activity decreases dietary iron absorption compared with rest. Energy deficit exacerbates both the hepcidin response to physical activity and declines in dietary iron absorption compared with energy balance. This trial was registered at clinicaltrials.gov as NCT03524690.
Abstract
Although Unmanned Aerial Vehicles (UAVs) are developed for military missions originally, they have been used widely in civil activities for several decades globally. In agricultural, UAVs ...have been developed as an efficient sprayer for pesticide application since 1987. UAV-based sprayers are popular for the prevention and control of pests and diseases in field crop in many countries recently. Some of the UAV-based sprayers are developed to be equipped with fruit tree mode aiming at solving droplet penetration in the inside and bottom part of the fruit tree canopy. In this study, a newly released UAV-based sprayer (i.e., T30) equipped fruit tree mode is chosen as spraying platform to optimize the spraying parameters for practical application. The flight velocity and application rate are the variables, while droplet coverage, density, size, and penetration are the observed metrics. Three treatments with different flight velocities (2 m s
-1
or 3 m s
-1
) or application rates (60 L ha
-1
or 75 L ha
-1
) are arranged to collect the droplets for assessment. Water Sensitive Papers (WSPs) are placed in the outside, bottom, and inside layers of the canopy to collect droplets. The results show that the treatment combined a flight velocity of 2 m s
-1
and an application rate of 60 L ha
-1
obtains the most droplets among all the variables based on the values of droplet coverage and density. The treatment with a flight velocity of 2 m s
-1
and an application rate of 75 L ha
-1
has the best penetration, while the treatment with a velocity of 2 m s
-1
and an application rate of 60 L ha
-1
takes the second place according to the percentages of droplet deposition in the three layers. Overall consideration of the total droplet distribution and penetration of the application parameters, a flight velocity of 2 m s
-1
and an application rate of 60 L ha
-1
are recommended to get an ideal droplet distribution in tree canopy when UAV-based sprayer T30 equipped with fruit tree mode flies at 1.6∼2 m above the citrus tree canopy.
Background
Current procedures for thawing and issuing of cryopreserved platelets (CPPs) are laborious and have remained challenging in emergency settings such as blood banks and military operations. ...In this prospective study, a novel processing method designed to facilitate the rapid issuance of CPPs with no postthaw handling required was developed and functionally characterized in parallel with standard CPPs manufactured.
Study Design and Methods
Double‐dose plateletpheresis units (n = 42) were cryopreserved at −80°C in 5%–6% dimethyl sulfoxide to produce matched pairs thawed successively over a 27‐month period for comparison between two processing arms. In contrast to the standard CPPs manufactured as standalone units, platelets were frozen in tandem with resuspending plasma in a distinct partition as a single unit in the novel method, herein referred to as tandem CPPs. Postthaw (PT) CPPs from both arms were assessed at PT0‐, 12‐, and 24‐h to measure platelet recovery, R‐time (time to clot initiation; min), and maximum amplitude (MA; clot strength; mm) using thromboelastography.
Results
In the overall dataset, mean platelet recovery was higher (p < .0005) for tandem CPPs (83.9%) compared with standard CPPs (73.3%) at PT0; mean R‐times were faster (p < .0005) for tandem CPPs (2.5–3.6 min) compared with standard CPPs (3.0–3.8 min); mean MA was higher for tandem CPPs (57.8–59.5 mm) compared with standard CPPs (52.1–55.8 mm) at each postthaw time point (p < .05).
Conclusion
Robust temporal dynamics of superior hemostatic functionality were established for tandem CPPs over extended cryopreservation up to 27 months and 24 h of postthaw storage.
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