Adaptive Threat Modeling for Secure Ad Hoc Routing Protocols

Secure routing protocols for mobile ad hoc networks provide the required functionality for proper network operation. If the underlying routing protocol cannot be trusted to follow the protocol operations, additional trust layers, such as authentication, cannot be obtained. Threat models drive analysis capabilities, affecting how we evaluate trust. Current attacker threat models limit the results obtained during protocol security analysis over ad hoc routing protocols. Developing a proper threat model to evaluate security properties in mobile ad hoc routing protocols presents a significant challenge. If the attacker strength is too weak, we miss vital security flaws. If the attacker strength is too strong, we cannot identify the minimum required attacker capabilities needed to break the routing protocol. In this paper we present an adaptive threat model to evaluate route discovery attacks against ad hoc routing protocols. Our approach enables us to evaluate trust in the ad hoc routing process and allows us to identify minimum requirements an attacker needs to break a given routing protocol

African Rice (Oryza glaberrima Steud.): Lost Crop of the Enslaved Africans Discovered in Suriname1

African Rice (Oryza glaberrimaSteud.): Lost Crop of the Enslaved Africans Discovered in Suriname. African rice (Oryza glaberrima Steud.) was introduced to the Americas during the slave trade years and grown by enslaved Africans for decades before mechanical milling devices facilitated the shift towards Asian rice (O. sativa L.). Literature suggests that African rice is still grown in Guyana and French Guiana, but the most recent herbarium voucher dates from 1938. In this paper, evidence is presented that O. glaberrima is still grown by Saramaccan Maroons both for food and ritual uses. Saramaccan informants claim their forefathers collected their first “black rice” from a mysterious wild rice swamp and cultivated these seeds afterwards. Unmilled spikelets (grains with their husk still attached) are sold in small quantities for ancestor offerings, and even exported to the Netherlands to be used by Maroon immigrants. Little is known of the evolution of O. glaberrima, before and after domestication. Therefore, more research is needed on the different varieties of rice and other “lost crops” grown by these descendants of enslaved Africans who escaped from plantations in the 17th and 18th centuries and maintained much of their African cultural heritage in the deep rainforest

The diverse nature of island isolation and its effect on land bridge insular faunas

Aim: Isolation is a key factor in island biology. It is usually defined as the distance to the geographically nearest mainland, but many other definitions exist. We explored how testing different isolation indices affects the inference of impacts of isolation on faunal characteristics. We focused on land bridge islands and compared the relationships of many spatial and temporal (i.e., through time) isolation indices with community‐, population‐ and individual‐level characteristics (species richness, population density and body size, respectively). Location: Aegean Sea islands, Greece. Time period: Current. Taxon: Many animal taxa. Methods: We estimated 21 isolation indices for 205 islands and recorded species richness data for 15 taxa (invertebrates and vertebrates). We obtained body size data for seven lizard species and population density data for three. We explored how well indices predict each characteristic, in each taxon, by conducting a series of ordinary least squares regressions (controlling for island area when needed) and a meta‐analysis. Results: Isolation was significantly (and negatively) associated with species richness in 10 of 15 taxa. It was significantly (and positively) associated with body size in only one of seven species and was not associated with population density. The effect of isolation on species richness was much weaker than that of island area, regardless of the index tested. Spatial indices generally out‐performed temporal indices, and indices directly related to the mainland out‐performed those related mainly to neighbouring islands. No index was universally superior to others, including the distance to the geographically nearest mainland. Main conclusions: The choice of index can alter our perception of the impacts of isolation on biological patterns. The nearly automatic, ubiquitous use of distance to the geographically nearest mainland misrepresents the complexity of the effects of isolation. We recommend the simultaneous testing of several indices that represent different aspects of isolation, in order to produce more constructive and thorough investigations and avoid imprecise inference

Disclosing physician ratings: performance effects and the difficulty of altering rating consensus

I examine effects of a health care system's policy to publicly disclose patient ratings of its physicians. I find evidence that this policy leads to performance improvement by the disclosed, subjective ratings and also by undisclosed, objective measures of quality. These effects are consistent with multitasking theory, in that physicians respond to the disclosure by providing more of a shared input—time with patients—that benefits performance by ratings and underlying quality. I also find, as predicted by information cascade theory, that the ratings become jammed to some degree near initially disclosed values. Specifically, raters observe the pattern of initial ratings and follow suit by providing similar ratings. Finally, I find evidence that physicians anticipate rating jamming and so concentrate their effort on earlier performance in order to set a pattern of high ratings that later ratings follow. These results demonstrate that the disclosure of subjective ratings can benefit performance broadly but can also shift effort toward earlier performance

Напрями формування та використання доходів місцевих бюджетів

У статті обґрунтовано основні завдання та проблеми у формуванні доходів, їх використання органами місцевого самоврядування і запропоновано напрями їх вирішення. Досліджено фінансову децентралізацію, податковий потенціал регіонів України. Розкрито поняття самостійності місцевих бюджетів.Substantiate the main tasks and challenges and suggested directions for their solution in the formation of revenues and their use by local governments. Investigate the financial decentralization, fiscal capacity of regions of Ukraine and the independence of local budgets

A Pilot Trial of Universal School-Based Mental Health Screening in El Salvador: Traumatic Stress in an Underresourced School Environment

Salvadoran youth have an elevated risk of trauma exposure and related mental health problems. However, investigations of childhood trauma exposure and mental health sequelae in El Salvador are limited. The present study aimed to (a) explore the prevalence of exposure to potentially traumatic events and symptoms of posttraumatic stress, anxiety, and depression and (b) evaluate the associations between specific trauma types and emotional functioning among Salvadoran youth. A total of 1,296 youth aged 8–21 years from seven public schools completed self-report measures of trauma exposure, posttraumatic stress symptoms (PTSS), anxiety, and depression. Participants reported high levels of trauma exposure, endorsing an average of 3.62 (SD = 2.32) trauma types. In total, 34.5% of participants reported clinically elevated PTSS; fewer youths reported elevated depressive (8.7%) and anxiety symptoms (8.6%). Although boys reported exposure to more trauma types than girls, d = 0.22, girls were more likely to endorse elevated PTSS, V = .11; anxiety, V = .06; and depression, V = .10. Adolescents reported exposure to more trauma types than younger children, d = 0.23, and were more likely to endorse elevated PTSS, V = .07; anxiety, V = .13; and depression, V = .16. Undergoing a frightening medical procedure, OR = 2.30; female sex, OR = 1.92; witnessing domestic violence, OR = 1.70; and experiencing war between gangs, OR = 1.61, were strong predictors of elevated PTSS. This broad, school-based screening was a critical step toward better understanding the rate of trauma exposure and trauma-related symptoms among Salvadoran youth

A Hierarchy of Scheduler Classes for Stochastic Automata

Stochastic automata are a formal compositional model for concurrent stochastic timed systems, with general distributions and non-deterministic choices. Measures of interest are defined over schedulers that resolve the nondeterminism. In this paper we investigate the power of various theoretically and practically motivated classes of schedulers, considering the classic complete-information view and a restriction to non-prophetic schedulers. We prove a hierarchy of scheduler classes w.r.t. unbounded probabilistic reachability. We find that, unlike Markovian formalisms, stochastic automata distinguish most classes even in this basic setting. Verification and strategy synthesis methods thus face a tradeoff between powerful and efficient classes. Using lightweight scheduler sampling, we explore this tradeoff and demonstrate the concept of a useful approximative verification technique for stochastic automata