Element redistribution along hydraulic and redox gradients of low-centered polygons, Lena Delta, northern Siberia

Wetland soils affected by permafrost are extensive in subarctic and arctic tundra. However, this fact does not imply these soils have been sufficiently investigated. In particular, studies of element translocation processes are scarce. This study was conducted (i) to determine the relationship between water and redox regimes in wetland soils in the Siberian tundra, and (ii) to investigate their influence on the distribution of redox sensitive and associate elements (Mn, Fe, P). Major geomorphic units were chosen (microhigh, polygon rim and slope; microlow, polygon center) from two low-centered polygons in the Lena Delta. Within polygons, redox potential, permafrost, and water level were measured during summer in 1999 and 2000 and (related) compared with element distribution. Manganese, Fe, and P accumulations were preferentially observed in aerobic microhighs. Anaerobic conditions in the microlows lead to a mobilization of Mn, Fe, and P. The elements migrate via water and are immobilized at the microhigh, which acts as an oxidative barrier. The element pattern, indicating an upward flux via water along redox gradients, is explained by higher evapotranspiration from soils and vegetation of the microhighs (Typic Aquiturbel) compared with soils and vegetation of the microlows (Typic Historthel). However, in further research this upward transport should be validated using labeled elements

Therapeutic implications of improved molecular diagnostics for rare CNS-embryonal tumor entities: results of an international, retrospective study

BACKGROUND: Only few data are available on treatment-associated behavior of distinct rare CNS-embryonal tumor entities previously treated as "CNS-primitive neuroectodermal tumors" (CNS-PNET). Respective data on specific entities, including CNS neuroblastoma, FOXR2 activated (CNS NB-FOXR2), and embryonal tumor with multi-layered rosettes (ETMR) are needed for development of differentiated treatment strategies. METHODS: Within this retrospective, international study, tumor samples of clinically well-annotated patients with the original diagnosis of CNS-PNET were analyzed using DNA methylation arrays (n=307). Additional cases (n=66) with DNA methylation pattern of CNS NB-FOXR2 were included irrespective of initial histological diagnosis. Pooled clinical data (n=292) were descriptively analyzed. RESULTS: DNA methylation profiling of "CNS-PNET" classified 58(19%) cases as ETMR, 57(19%) as HGG, 36(12%) as CNS NB-FOXR2, and 89(29%) cases were classified into 18 other entities. Sixty-seven (22%) cases did not show DNA methylation patterns similar to established CNS tumor reference classes. Best treatment results were achieved for CNS NB-FOXR2 patients (5-year PFS: 63%±7%, OS: 85%±5%, n=63), with 35/42 progression-free survivors after upfront craniospinal irradiation (CSI) and chemotherapy. The worst outcome was seen for ETMR and HGG patients with 5-year PFS of 18%±6% and 22%±7%, and 5-year OS of 24%±6% and 25%±7%, respectively. CONCLUSION: The historically reported poor outcome of CNS-PNET patients becomes highly variable when tumors are molecularly classified based on DNA methylation profiling. Patients with CNS NB-FOXR2 responded well to current treatments and a standard-risk-CSI based regimen may be prospectively evaluated. The poor outcome of ETMR across applied treatment strategies substantiates the necessity for evaluation of novel treatments

Not on my phone: Exploring users conception of related permissions

Many smartphone security mechanisms prompt users to decide on sensitive resource requests. This approach fails if corresponding implications are not understood. Prior work identified ineffective user interfaces as a cause for insufficient comprehension and proposed augmented dialogs. We hypothesize that, prior to interface-design, efficient security dialogs require an underlying permission model based on user demands. We believe, that only an implementation which corresponds to users» mental models, in terms of the handling, granularity and grouping of permission requests, allows for informed decisions. In this work, we propose a study design which leverages materialization for the extraction of the mental models. We present preliminary results of three Focus Groups. The findings indicate that the materialization provided sufficient support for non-experts to understand and discuss this complex topic. In addition to this, the results indicate that current permission approaches do not match users» demands for information and control

My scrawl hides it all: Protecting text messages against shoulder surfing with handwritten fonts

We present a novel concept for protecting text messages (e.g. notifications) on mobile devices from shoulder surfing. We propose to display the text in the user's handwriting, assuming that people can read their own handwriting easier and faster than strangers. Our approach was evaluated in a proof-of-concept user study that revealed significant differences in reading time: Participants were indeed slower when reading the unfamiliar handwriting of the other participants compared to their own, and they tended to make more errors. Even though this effect was not present for all participants, we argue that our results may provide the basis for protection mechanisms applicable in real-world scenarios

"Get a Free Item Pack with Every Activation!". Do Incentives Increase the Adoption Rates of Two-Factor Authentication?

Account security is an ongoing issue in practice. Two-Factor Authentication (2FA) is a mechanism which could help mitigate this problem, however adoption is not very high in most domains. Online gaming has adopted an interesting approach to drive adoption: Games offer small rewards such as visual modifications to the player’s avatar’s appearance, if players utilize 2FA. In this paper, we evaluate the effectiveness of these incentives and investigate how they can be applied to non-gaming contexts. We conducted two surveys, one recruiting gamers and one recruiting from a general population. In addition, we conducted three focus group interviews to evaluate various incentive designs for both, the gaming context and the non-gaming context. We found that visual modifications, which are the most popular type of gaming-related incentives, are not as popular in non-gaming contexts. However, our design explorations indicate that well-chosen incentives have the potential to lead to more users adopting 2FA, even outside of the gaming context

"If you want, I can store the encrypted password". A Password-Storage Field Study with Freelance Developers

In 2017 and 2018, Naiakshina et al. [21, 22] studied in a lab setting whether computer science students need to be told to write code that stores passwords securely. The authors' results showed that, without explicit prompting, none of the students implemented secure password storage. When asked about this oversight, a common answer was that they would have implemented secure storage - if they were creating code for a company. To shed light on this possible confusion, we conducted a mixed-methods field study with developers. We hired free-lance developers online and gave them a similar password storage task followed by a questionnaire to gain additional insights into their work. From our research, we offer two contributions. First of all, we reveal that, similar to the students, freelancers do not store passwords securely unless prompted, they have misconceptions about secure password storage, and they use outdated methods. Secondly, we discuss the methodological implications of using freelancers and students in developer studies

You can't watch this! Privacy-respectful photo browsing on smartphones

We present an approach to protect photos on smartphones from unwanted observations by distorting them in a way that makes it hard or impossible to recognize their content for an onlooker who does not know the photographs. On the other hand, due to the chosen way of distortion, the device owners who know the original images have no problems recognizing photos. We report the results of a user study (n=18) that showed very high usability properties for all tested graphical filters (only 11 out of 216 distorted photos were not correctly identified by their owners). At the same time, two of the filters significantly reduced the observability of the image contents

SwiPIN: Fast and secure PIN-entry on smartphones

In this paper, we present SwiPIN, a novel authentication system that allows input of traditional PINs using simple touch gestures like up or down and makes it secure against human observers. We present two user studies which evaluated different designs of SwiPIN and compared it against traditional PIN. The results show that SwiPIN performs adequately fast (3.7 s) to serve as an alternative input method for risky situations. Furthermore, SwiPIN is easy to use, significantly more secure against shoulder surfing attacks and switching between PIN and SwiPIN feels natural