122 research outputs found
Genomic and gene regulatory signatures of cryptozoic adaptation: Loss of blue sensitive photoreceptors through expansion of long wavelength-opsin expression in the red flour beetle Tribolium castaneum
Abstract
Background
Recent genome sequence analysis in the red flour beetle Tribolium castaneum indicated that this highly crepuscular animal encodes only two single opsin paralogs: a UV-opsin and a long wavelength (LW)-opsin; however, these animals do not encode a blue (B)-opsin as most other insects. Here, we studied the spatial regulation of the Tribolium single LW- and UV-opsin gene paralogs in comparison to that of the five opsin paralogs in the retina of Drosophila melanogaster.
Results
In situ hybridization analysis reveals that the Tribolium retina, in contrast with other insect retinas, constitutes a homogenous field of ommatidia that have seven LW-opsin expressing photoreceptors and one UV-/LW-opsin co-expressing photoreceptor per eye unit. This pattern is consistent with the loss of photoreceptors sensitive to blue wavelengths. It also identifies Tribolium as the first example of a species in insects that co-expresses two different opsins across the entire retina in violation of the widely observed one receptor rule of sensory cells.
Conclusion
Broader studies of opsin evolution in darkling beetles and other coleopteran groups have the potential to pinpoint the permissive and adaptive forces that played a role in the evolution of vision in Tribolium castaneum
MuTent: Dynamic Android Intent Protection with Ownership-Based Key Distribution and Security Contracts
Intents are the plain-text based message object used for ICC by the Android framework. Hence the framework essentially lacks an inbuilt security mechanism to protect the visibility, accessibility, and integrity of Intent\u27s data that facilitates adversaries to intercept or manipulate the data. In this work, we investigate the Intent protection mechanism and propose a security-enhanced Intent library MuTent that allows Android apps to securely exchange sensitive data during ICC. Differently from the existing mechanism, MuTent provides accessibility and visibility of Intent data by validating the receiver\u27s capability and provides integrity by using encryption and the Arc security contract code. Especially, ICC is initiated by exchanging MuTent and follows a novel ownership-based key distribution model, that restricts the malware apps without permission from deciphering data. Through the evaluation, we show that MuTent can improve the security for popular Android apps with minimal performance overheads, demonstrated using F-Droid apps
Probabilistic Naming of Functions in Stripped Binaries
Debugging symbols in binary executables carry the names of functions and global variables. When present, they greatly simplify the process of reverse engineering, but they are almost always removed (stripped) for deployment. We present the design and implementation of punstrip, a tool which combines a probabilistic fingerprint of binary code based on high-level features with a probabilistic graphical model to learn the relationship between function names and program structure. As there are many naming conventions and developer styles, functions from different applications do not necessarily have the exact same name, even if they implement the exact same functionality. We therefore evaluate punstrip across three levels of name matching: exact; an approach based on natural language processing of name components; and using Symbol2Vec, a new embedding of function names based on random walks of function call graphs. We show that our approach is able to recognize functions compiled across different compilers and optimization levels and then demonstrate that punstrip can predict semantically similar function names based on code structure. We evaluate our approach over open source C binaries from the Debian Linux distribution and compare against the state of the art
Devil is Virtual: Reversing Virtual Inheritance in C++ Binaries
Complexities that arise from implementation of object-oriented concepts in
C++ such as virtual dispatch and dynamic type casting have attracted the
attention of attackers and defenders alike.
Binary-level defenses are dependent on full and precise recovery of class
inheritance tree of a given program.
While current solutions focus on recovering single and multiple inheritances
from the binary, they are oblivious to virtual inheritance. Conventional wisdom
among binary-level defenses is that virtual inheritance is uncommon and/or
support for single and multiple inheritances provides implicit support for
virtual inheritance. In this paper, we show neither to be true.
Specifically, (1) we present an efficient technique to detect virtual
inheritance in C++ binaries and show through a study that virtual inheritance
can be found in non-negligible number (more than 10\% on Linux and 12.5\% on
Windows) of real-world C++ programs including Mysql and libstdc++. (2) we show
that failure to handle virtual inheritance introduces both false positives and
false negatives in the hierarchy tree. These false positves and negatives
either introduce attack surface when the hierarchy recovered is used to enforce
CFI policies, or make the hierarchy difficult to understand when it is needed
for program understanding (e.g., during decompilation). (3) We present a
solution to recover virtual inheritance from COTS binaries. We recover a
maximum of 95\% and 95.5\% (GCC -O0) and a minimum of 77.5\% and 73.8\% (Clang
-O2) of virtual and intermediate bases respectively in the virtual inheritance
tree.Comment: Accepted at CCS20. This is a technical report versio
Incidence of acute cerebrovascular events in patients with rheumatic or calcific mitral stenosis: a systematic review and meta-analysis
Background
Patients with mitral stenosis (MS) may be predisposed to acute cerebrovascular events (ACE) and peripheral thromboembolic events (TEE). Concomitant atrial fibrillation (AF), mitral annular calcification (MAC) and rheumatic heart disease (RHD) are independent risk factors. Our aim was to evaluate the incidence of ACEs in MS patients and the implications of AF, MAC, and RHD on thromboembolic risks.
Methods
This systematic review was registered on PROSPERO (CRD42021291316). Six databases were searched from inception to 19th December 2021. The clinical outcomes were composite ACE, ischaemic stroke/transient ischaemic attack (TIA), and peripheral TEE.
Results
We included 16 and 9 papers, respectively, in our qualitative and quantitative analyses. The MS cohort with AF had the highest incidence of composite ACE (31.55%; 95%CI 3.60-85.03; I
2
=99%), followed by the MAC (14.85%; 95%CI 7.21-28.11; I
2
=98%), overall MS (8.30%; 95%CI 3.45-18.63; I
2
=96%) and rheumatic MS population (4.92%; 95%CI 3.53-6.83; I
2
=38%). Stroke/TIA were reported in 29.62% of the concomitant AF subgroup (95%CI 2.91-85.51; I
2
=99%) and in 7.11% of the overall MS patients (95%CI 1.91-23.16; I
2
=97%). However, the heterogeneity of the pooled incidence of clinical outcomes in all groups, except the rheumatic MS group, were substantial and significant. The logit-transformed proportion of composite ACE increased by 0.0141 (95% CI 0.0111-0.0171; p<0.01) per year of follow-up.
Conclusion
In the MS population, MAC and concomitant AF are risk factors for the development of ACE. The scarcity of data in our systematic review reflects the need for further studies to explore thromboembolic risks in all MS subtypes
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2âto end preventable child deaths by 2030âwe need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000â2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
Burden of injury along the development spectrum : associations between the Socio-demographic Index and disability-adjusted life year estimates from the Global Burden of Disease Study 2017
Background The epidemiological transition of non-communicable diseases replacing infectious diseases as the main contributors to disease burden has been well documented in global health literature. Less focus, however, has been given to the relationship between sociodemographic changes and injury. The aim of this study was to examine the association between disability-adjusted life years (DALYs) from injury for 195 countries and territories at different levels along the development spectrum between 1990 and 2017 based on the Global Burden of Disease (GBD) 2017 estimates. Methods Injury mortality was estimated using the GBD mortality database, corrections for garbage coding and CODEm-the cause of death ensemble modelling tool. Morbidity estimation was based on surveys and inpatient and outpatient data sets for 30 cause-of-injury with 47 nature-of-injury categories each. The Socio-demographic Index (SDI) is a composite indicator that includes lagged income per capita, average educational attainment over age 15 years and total fertility rate. Results For many causes of injury, age-standardised DALY rates declined with increasing SDI, although road injury, interpersonal violence and self-harm did not follow this pattern. Particularly for self-harm opposing patterns were observed in regions with similar SDI levels. For road injuries, this effect was less pronounced. Conclusions The overall global pattern is that of declining injury burden with increasing SDI. However, not all injuries follow this pattern, which suggests multiple underlying mechanisms influencing injury DALYs. There is a need for a detailed understanding of these patterns to help to inform national and global efforts to address injury-related health outcomes across the development spectrum.Peer reviewe
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