1,882 research outputs found

    Design and Cryptanalysis of a Customizable Authenticated Encryption Algorithm

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    It is common knowledge that encryption is a useful tool for providing confidentiality. Authentication, however, is often overlooked. Authentication provides data integrity; it helps ensure that any tampering with or corruption of data is detected. It also provides assurance of message origin. Authenticated encryption (AE) algorithms provide both confidentiality and integrity / authenticity by processing plaintext and producing both ciphertext and a Message Authentication Code (MAC). It has been shown too many times throughout history that encryption without authentication is generally insecure. This has recently culminated in a push for new authenticated encryption algorithms. There are several authenticated encryption algorithms in existence already. However, these algorithms are often difficult to use correctly in practice. This is a significant problem because misusing AE constructions can result in reduced security in many cases. Furthermore, many existing algorithms have numerous undesirable features. For example, these algorithms often require two passes of the underlying cryptographic primitive to yield the ciphertext and MAC. This results in a longer runtime. It is clear that new easy-to-use, single-pass, and highly secure AE constructions are needed. Additionally, a new AE algorithm is needed that meets stringent requirements for use in the military and government sectors. This thesis explores the design and cryptanalysis of a novel, easily customizable AE algorithm based on the duplex construction. Emphasis is placed on designing a secure pseudorandom permutation (PRP) for use within the construction. A survey of state of the art cryptanalysis methods is performed and the resistance of our algorithm against such methods is considered. The end result is an algorithm that is believed to be highly secure and that should remain secure if customizations are made within the provided guidelines

    A Guide to Designing: The Ultimate WPI PAX East Booth

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    Our objective for this project was to plan, design, and execute an exhibitor’s booth representing the WPI IMGD program at the Penny Arcade Expo East 2017. We researched experiences of the past two PAX project groups, extensively collaborated with WPI’s Marketing department to design and create content for the booth, and selected student games to showcase. Our goals to brand WPI and WPI IMGD at the event was overall a success

    Life-history diversity and productivity of Puget Sound Chinook salmon

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    Puget Sound Chinook are listed as threatened under the U.S. Endangered Species Act, and efforts to recover these populations are underway. Effective planning and implementation of conservation measures designed to promote recovery require knowledge of freshwater processes governing smolt production and juvenile rearing strategies. The Washington Department of Fish and Wildlife monitors these viability parameters through a network of smolt trapping sites throughout Puget Sound including the Nisqually River, Green River, Cedar River, Skagit River and Dungeness River. At these locations, we routinely observe two distinct pulses of subyearling migration: an early movement of small fry (\u3c 45 mm) captured immediately following emergence, and a later migration of larger parr (\u3e 45 mm) that rear and grow in freshwater for a variable period of time. Yearling Chinook are occasionally observed, but only at extremely low catches, and only in basins with cold, snow or glacial dominated headwaters. In terms of productivity, Ricker stock-recruit analysis provides evidence for density-dependence of parr but not fry abundance. This suggests limitation in the availability of rearing habitat for parr, and we hypothesize that fry migrants move downstream because they are unable to acquire rearing territories in habitats saturated with conspecifics. In watersheds where this result is observed, habitat restoration efforts that augment parr rearing habitat would have the greatest opportunity to benefit Chinook salmon productivity. We also find evidence for strong effects of stream flow on Chinook productivity, often as a negative relationship between peak flow and survival. Finally, our smolt trapping estimates permit analysis of smolt to adult return rates, which will also be presented

    Season of Prescribed Fire Determines Grassland Restoration Outcomes After Fire Exclusion and Overgrazing

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    Fire exclusion and mismanaged grazing are globally important drivers of environmental change in mesic C4 grasslands and savannas. Although interest is growing in prescribed fire for grassland restoration, we have little long-term experimental evidence of the influence of burn season on the recovery of herbaceous plant communities, encroachment by trees and shrubs, and invasion by exotic grasses. We conducted a prescribed fire experiment (seven burns between 2001 and 2019) in historically fire-excluded and overgrazed grasslands of central Texas. Sites were assigned to one of four experimental treatments: summer burns (warm season, lightning season), fall burns (early cool season), winter burns (late cool season), or unburned (fire exclusion). To assess restoration outcomes of the experiment, in 2019, we identified old-growth grasslands to serve as reference sites. Herbaceous-layer plant communities in all experimental sites were compositionally and functionally distinct from old-growth grasslands, with little recovery of perennial C4 grasses and long-lived forbs. Unburned sites were characterized by several species of tree, shrub, and vine; summer sites were characterized by certain C3 grasses and forbs; and fall and winter sites were intermediate in composition to the unburned and summer sites. Despite compositional differences, all treatments had comparable plot-level plant species richness (range 89–95 species/1000 m2). At the local-scale, summer sites (23 species/m2) and old-growth grasslands (20 species/m2) supported greater richness than unburned sites (15 species/m2), but did not differ significantly from fall or winter sites. Among fire treatments, summer and winter burns most consistently produced the vegetation structure of old-growth grasslands (e.g., mean woody canopy cover of 9%). But whereas winter burns promoted the invasive grass Bothriochloa ischaemum by maintaining areas with low canopy cover, summer burns simultaneously limited woody encroachment and controlled B. ischaemum invasion. Our results support a growing body of literature that shows that prescribed fire alone, without the introduction of plant propagules, cannot necessarily restore old-growth grassland community composition. Nonetheless, this long-term experiment demonstrates that prescribed burns implemented in the summer can benefit restoration by preventing woody encroachment while also controlling an invasive grass. We suggest that fire season deserves greater attention in grassland restoration planning and ecological research

    Early Career Professionals’ (Researchers, Practitioners, and Policymakers) Role in Advocating, Disseminating, and Implementing the Global Action Plan on Physical Activity: ISPAH Early Career Network View

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    Increasing population levels of physical activity (PA) can assist in achieving the United Nations sustainable development goals,benefiting multiple sectors and contributing to global prosperity. Practices and policies to increase PA levels exist at thesubnational, national, and international levels. In 2018, the World Health Organization launched the first Global Action Plan onPhysical Activity (GAPPA). The GAPPA provides guidance through a framework of effective and feasible policy actions forincreasing PA, and requires engagement and advocacy from a wide spectrum of stakeholders for successful implementationof the proposed actions. Early career professionals, including researchers, practitioners, and policymakers, can play a majorrole with helping “all people being regularly active” by contributing to 4 overarching areas: (1) generation—of evidence,(2) dissemination—of key messages and evidence, (3) implementation—of the evidence-based actions proposed in the GAPPA,and (4) contributing to advocacy for robust national action plans on PA. The contribution of early career professionals can beachieved through 5 pathways: (1) research, (2) workplace/practice, (3) business, (4) policy, and (5) professional and publicopinion. Recommendations of how early career professionals can contribute to the generation, dissemination, and implementation of the evidence and actions proposed by the GAPPA are provided

    Dance Exposure, Individual Characteristics, and Injury Risk over Five Seasons in a Professional Ballet Company

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    PURPOSE: To describe the relationships between dance exposure, dancer characteristics, and injury risk across five seasons in a professional ballet company. METHODS: Dance exposure time and clinician-reported time-loss and medical attention injury data were prospectively collected from 118 professional dancers of The Royal Ballet between 2015/16 and 2019/20. Cox proportional hazards and shared frailty models were fitted to overuse and traumatic injuries; individualized robust Z-scores for 7-day and 28-day accumulated exposure, and week-to-week change in exposure, age, sex, company rank, and injury history were included as time-varying covariates. RESULTS: Across 381,710 h of exposure, 1332 medical attention and 427 time-loss injuries were observed. Positive relationships were observed between week-to-week change in exposure and overuse time-loss (+1 Z-score hazard ratio (HR): 1.27, 95% confidence interval (CI): 1.06-1.53) and medical attention injury risk (+1 Z-score HR: 1.17, 95% CI: 1.06-1.28). A negative relationship was observed between 7-day accumulated exposure and overuse medical-attention injury risk (+1 Z-score HR: 0.74, 95% CI: 0.66-0.84). Overuse time-loss injury risk was greater in soloists compared to the corps de ballet (HR: 1.47, 95% CI: 1.01-2.15), and in dancers with a higher previous injury rate (+1 injury.1000 h-1 HR: 1.06, 95% CI: 1.02-1.10). Only age was associated with traumatic time-loss (+1-year HR: 1.05, 95% CI: 1.01-1.09) or medical attention injury risk (+1-year HR: 1.04, 95% CI: 1.01-1.07). CONCLUSION: Professional ballet companies should implement training principles such as periodization and progression, particularly in the case of senior-ranking dancers, older dancers, and dancers with high rates of previous injury. These findings provide a basis for future prospective investigations into specific causal injury pathways

    Sustained expansion of NKT cells and antigen-specific T cells after injection of α-galactosyl-ceramide loaded mature dendritic cells in cancer patients

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    Natural killer T (NKT) cells are distinct glycolipid reactive innate lymphocytes that are implicated in the resistance to pathogens and tumors. Earlier attempts to mobilize NKT cells, specifically, in vivo in humans met with limited success. Here, we evaluated intravenous injection of monocyte-derived mature DCs that were loaded with a synthetic NKT cell ligand, α-galactosyl-ceramide (α-GalCer; KRN-7000) in five patients who had advanced cancer. Injection of α-GalCer–pulsed, but not unpulsed, dendritic cells (DCs) led to >100-fold expansion of several subsets of NKT cells in all patients; these could be detected for up to 6 mo after vaccination. NKT activation was associated with an increase in serum levels of interleukin-12 p40 and IFN-γ inducible protein-10. In addition, there was an increase in memory CD8(+) T cells specific for cytomegalovirus in vivo in response to α-GalCer–loaded DCs, but not unpulsed DCs. These data demonstrate the feasibility of sustained expansion of NKT cells in vivo in humans, including patients who have advanced cancer, and suggest that NKT activation might help to boost adaptive T cell immunity in vivo

    Within-Compound Versus Public Latrine Access and Child Feces Disposal Practices in Low-Income Neighborhoods of Accra, Ghana.

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    In crowded urban settlements in low-income countries, many households rely on shared sanitation facilities. Shared facilities are not currently considered "improved sanitation" because of concerns about whether hygiene conditions sufficiently protect users from the feces of others. Prevention of fecal exposure at a latrine is only one aspect of sanitary safety. Ensuring consistent use of latrines for feces disposal, especially child feces, is required to reduce fecal contamination in households and communities. Household crowding and shared latrine access are correlated in these settings, rendering latrine use by neighbors sharing communal living areas as critically important for protecting one's own household. This study in Accra, Ghana, found that household access to a within-compound basic latrine was associated with higher latrine use by children of ages 5-12 years and for disposal of feces of children < 5 years, compared with households using public latrines. However, within-compound access was not associated with improved child feces disposal by other caregivers in the compound. Feces was rarely observed in household compounds but was observed more often in compounds with latrines versus compounds relying on public latrines. Escherichia coli and human adenovirus were detected frequently on household surfaces, but concentrations did not differ when compared by latrine access or usage practices. The differences in latrine use for households sharing within-compound versus public latrines in Accra suggest that disaggregated shared sanitation categories may be useful in monitoring global progress in sanitation coverage. However, compound access did not completely ensure that households were protected from feces and microbial contamination
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