Quantitative patterns in drone wars

Attacks by drones (i.e., unmanned combat air vehicles) continue to generate heated political and ethical debates. Here we examine the quantitative nature of drone attacks, focusing on how their intensity and frequency compare with that of other forms of human conflict. Instead of the power-law distribution found recently for insurgent and terrorist attacks, the severity of attacks is more akin to lognormal and exponential distributions, suggesting that the dynamics underlying drone attacks lie beyond these other forms of human conflict. We find that the pattern in the timing of attacks is consistent with one side having almost complete control, an important if expected result. We show that these novel features can be reproduced and understood using a generative mathematical model in which resource allocation to the dominant side is regulated through a feedback loop.Comment: 5 pages, 3 figure

Effect of Ebola virus proteins GP, NP and VP35 on VP40 VLP morphology

Recently we described a role for Ebola virus proteins, NP, GP, and VP35 in enhancement of VP40 VLP budding. To explore the possibility that VLP structure was altered by co-expression of EBOV proteins leading to the observed enhancement of VP40 VLP budding, we performed density gradient analysis as well as electron microscopy studies. Our data suggest that VP40 is the major determinant of VLP morphology, as co-expression of NP, GP and VP35 did not significantly change VLP density, length, and diameter. Ultra-structural changes were noted in the core of the VLPs when NP was co-expressed with VP40. Overall, these findings indicate that major changes in morphology of VP40 VLPs were likely not responsible for enhanced budding of VP40 VLPs in the presence of GP, NP and/or VP35

Qualitative Factors as Determinants of Continued Success:An Examination of eBusiness Entrepreneurial Firms Using the NewVenture Template

In this study, we analyze eBusiness entrepreneurs nominated by the Ernst & Young Entrepreneur of the Year Award program to ascertain whether qualitative factors are correlated with success. We find qualitative factors are incrementally informative above and beyond the information provided by quantitative factors. More specifically, firms that are able to maintain their innovative strategies by improving upon the product (or service) they offer and are able to meet the long-term needs of the customer are more likely to experience increased sales growth and have greater access to capital which results in a successful harvest strategy

Code wars: steganography, signals intelligence, and terrorism

This paper describes and discusses the process of secret communication known as steganography. The argument advanced here is that terrorists are unlikely to be employing digital steganography to facilitate secret intra-group communication as has been claimed. This is because terrorist use of digital steganography is both technically and operationally implausible. The position adopted in this paper is that terrorists are likely to employ low-tech steganography such as semagrams and null ciphers instead

Late-Summer Abundance and Distribution of Marine Birds in Kasegaluk Lagoon, Chukchi Sea, Alaska

Oil and gas drilling programs in the Alaska Chukchi Sea were carried out on leases offshore from Kasegaluk Lagoon in 1989-91, and further exploration and development activities in this area are likely in future years. We conducted aerial surveys between late July and early September 1989-91 to determine the distribution and abundance of marine birds in the Kasegaluk Lagoon area. We hypothesized that Kasegaluk Lagoon supported an avifauna similar to that found in other lagoon systems in arctic Alaska. In fact, the richness and diversity of bird species using Kasegaluk Lagoon were greater than in lagoon systems in the Beaufort Sea. Brant (Branta bernicla) was the most abundant species in Kasegaluk Lagoon compared to lagoons in the Beaufort Sea, where the Oldsquaw (Clangula hyemalis) is the dominant species. Several other species or species groups, such as Glaucous Gull (Larus hyperboreus), Arctic Tern (Sterna Paradisaea), small shorebirds (mainly Calidris and Phalaropus), and Lesser Snow Goose (Chen caerulescens) were also relatively abundant in Kasegaluk Lagoon.Key words: waterbirds, aerial surveys, lagoon ecosystems, Kasegaluk Lagoon, Chukchi Sea, Beaufort Sea, AlaskaDes programmes de forage pétrolier et gazier ont été exécutés dans la portion alaskienne de la mer des Tchouktches, sur des concessions au large de l'étang côtier Kasegaluk de 1989 à 1991, et on prévoit que d'autres activités reliées à l'exploration et au développement auront lieu à cet endroit dans les années à venir. On a effectué des relevés aériens entre la fin de juillet et le début de septembre de 1989 à 1991, afin de déterminer la distribution et l'abondance des oiseaux marins dans la région de l'étang côtier Kasegaluk. On avait émis l'hypothèse que cet étang était le refuge d'une avifaune semblable à celle qui se trouve dans d'autres systèmes lagunaires dans l'Alaska arctique. En réalité, la richesse et la diversité des espèces d'oiseaux utilisant l'étang Kasegaluk étaient supérieures à celles des systèmes lagunaires de la mer de Beaufort. La bernache cravant (Branta bernicla) représentait l'espèce la plus abondante de l'étang côtier Kasegaluk comparé aux étangs côtiers de la mer de Beaufort, où le canard kakawi (Clangula hyemalis) est l'espèce dominante. Plusieurs autres espèces ou groupes d'espèces, comme le goéland bourgmestre (Larus hyperboreus), la sterne arctique (Sterna paradisaea), les petits oiseaux de rivage (surtout Calidris et Phalaropus) et la petite oie blanche (Chen caerulescens) étaient relativement abondants dans l'étang côtier Kasegaluk.Mots clés : oiseaux aquatiques, relevés aériense,écosystèmes lagunaires, étang côtier Kasegaluk, mer des Tchouktches, mer de Beaufort, Alask

Flood Routing on the Illinois River in Oklahoma

Sanitary and Public Health Engineerin

10261 Abstracts Collection -- Algorithm Engineering

From June 27 to July 2, the Dagstuhl Seminar 10261 ``Algorithm Engineering \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Ebola Virus Localization in the Macaque Reproductive Tract during Acute Ebola Virus Disease.

Sexual transmission of Ebola virus (EBOV) has been demonstrated more than a year after recovery from the acute phase of Ebola virus disease (EVD). The mechanisms underlying EBOV persistence and sexual transmission are not currently understood. Using the acute macaque model of EVD, we hypothesized EBOV would infect the reproductive tissues and sought to localize the infection in these tissues using immunohistochemistry and transmission electron microscopy. In four female and eight male macaques that succumbed to EVD between 6 and 9 days after EBOV challenge, we demonstrate widespread EBOV infection of the interstitial tissues and endothelium in the ovary, uterus, testis, seminal vesicle, epididymis, and prostate gland, with minimal associated tissue immune response or organ pathology. Given the widespread involvement of EBOV in the reproductive tracts of both male and female macaques, it is reasonable to surmise that our understanding of the mechanisms underlying sexual transmission of EVD and persistence of EBOV in immune-privileged sites would be facilitated by the development of a nonhuman primate model in which the macaques survived past the acute stage into convalescence

Receiver Performance for an Enhanced DGPS Data Channel

The Coast Guard currently operates a maritime differential GPS service consisting of two control centers and over 85 remote broadcast sites. This service broadcasts GPS correction information on marine radiobeacon frequencies to improve the accuracy and integrity of GPS. The existing system provides differential corrections over a medium frequency carrier using minimum shift keying (MSK) as the modulation method. MSK is a version of the Continuous Phase Frequency Shift Keying (CPFSK) modulation technique that is spectrally compact, meaning that it is a narrow band modulation scheme. In a binary signaling channel, the two instantaneous frequencies for this modulation method are chosen in such a way so as to produce orthogonal signaling with a minimum modulation index. Current DGPS corrections are transmitted at a relatively low data rate, with message structures designed in an era when Selective Availability was in full operation. Greater demands for accuracy coupled with current operations in a post SA environment have prompted a reexamination of the DGPS data and signal structure, with an eye towards improving information rate while minimizing legacy user impact. A two-phased plan for a new generation of DGPS capability can be envisioned. In the first phase (near-term) new ionospheric messages would be introduced to allow greater DGPS accuracy at larger distances from the beacons. This capability could support both double (LI/L2) and triple (L1/L2/L5) frequency operation. This phase requires only the definition of the new message type(s) and the commitment of receiver manufacturers to implement the usage of the new data. In the second phase (intermediate future) a new signal would come on line to support RTK using two and three frequencies and homeland security messaging. This signal would have the capacity to send 500 bps or so without disrupting the legacy signal or legacy receiver performance. This new signal could be one of the new modulation techniques that we have been investigating; phase trellis overlay and orthogonal frequency division multiplexing. Preliminary examinations of both of these techniques have shown the potential for increased bandwidth usage (ION NTM Jan. 2004), the effects on legacy receiver performance through a modulator test-bed (ION AM June 2004), and some effects of an actual transmitter (including antenna and coupler) on the signal (ION GNSS Sept 2004). The current paper describes recent investigations into the architecture of the receivers for these modulation methods including details of the demodulation and decoding methods. We also establish receiver performance measures and present preliminary performance results. Reprinted with permission from The Institute of Navigation (http://ion.org/) and The Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation, (pp. 788-800). Fairfax, VA: The Institute of Navigation