Miracle-dz/UniFAR-FTUs huggingface dataset:
Why Botnets Work: Distributed Brute-Force Attacks Need No Synchronization

In September 2017, the McAfee Labs quarterly report estimated that brute-force attacks represent 20% of total network attacks, making them the most prevalent type of attack ex-aequo with browser-based vulnerabilities. These attacks have sometimes catastrophic consequences, and understanding their fundamental limits may play an important role in the risk assessment of password-secured systems and in the design of better security protocols. While some solutions exist to prevent online brute-force attacks that arise from one single IP address, attacks performed by botnets are more challenging. In this paper, we analyze these distributed attacks by using a simplified model. Our aim is to understand the impact of distribution and asynchronization on the overall computational effort necessary to breach a system. Our result is based on guesswork, a measure of the number of queries (guesses) before a correct sequence, such as a password, is found in an optimal attack. Guesswork is a direct surrogate for time and computational effort of guessing a sequence from a set of sequences with the associated likelihoods. We model the lack of synchronization by a worst-case optimization in which the queries made by multiple adversarial agents are received in the worst possible order for the adversary, resulting in a min–max formulation. We show that, even without synchronization, and for sequences of growing length, the asymptotic optimal performance is achievable by using randomized guesses drawn from an appropriate distribution. Therefore, randomization is key for the distributed asynchronous attacks. In other words, asynchronous guessers can asymptotically perform brute-force attacks as efficiently as synchronized guessers.
Exascale Interconnect Topology Characterization and Parameter Exploration

Exascale promotes numerous new challenges in supercomputer designs; Interconnect topology is one of them. Emerging interconnect topologies have been proposed but have not been thoroughly studied at large scale. In this study, we use a cycle-accurate simulator to conduct a design space exploration for both new and traditional interconnect topologies at the scale of 50,000 and 100,000 node networks. For each topology, we evaluate the performance with various network parameters (link latency and bandwidth), routing algorithms and multiple prevalent MPI workloads. Using these, we are able to characterize these topologies with regards to workloads, network parameters, and scalability to provide insights on the network system design for future Exascale systems.
Prohibitin is a positive modulator of mitochondrial function in PC12 cells under oxidative stress

Prohibitin (PHB) is a ubiquitously expressed and evolutionarily conserved mitochondrial protein with multiple functions. We have recently shown that PHB up‐regulation offers robust protection against neuronal injury in models of cerebral ischemia in vitro and in vivo, but the mechanism by which PHB affords neuroprotection remains to be elucidated. Here, we manipulated PHB expression in PC12 neural cells to investigate its impact on mitochondrial function and the mechanisms whereby it protects cells exposed to oxidative stress. PHB over‐expression promoted cell survival, whereas PHB down‐regulation diminished cell viability. Functionally, manipulation of PHB levels did not affect basal mitochondrial respiration, but it increased spare respiratory capacity. Moreover, PHB over‐expression preserved mitochondrial respiratory function of cells exposed to oxidative stress. Preserved respiratory capacity in differentiated PHB over‐expressing cells exposed to oxidative stress was associated with an elongated mitochondrial morphology, whereas PHB down‐regulation enhanced fragmentation. Mitochondrial complex I oxidative degradation was attenuated by PHB over‐expression and increased in PHB knockdown cells. Changes in complex I degradation were associated with alterations of respiratory chain supercomplexes. Furthermore, we showed that PHB directly interacts with cardiolipin and that down‐regulation of PHB results in loss of cardiolipin in mitochondria, which may contribute to destabilizing respiratory chain supercomplexes. Taken together, these data demonstrate that PHB modulates mitochondrial integrity and bioenergetics under oxidative stress, and suggest that the protective effect of PHB is mediated by stabilization of the mitochondrial respiratory machinery and its functional capacity, by the regulation of cardiolipin content.
What Are the Odds? Modern Relevance and Bayes Factor Solutions for MacAlister’s Problem From the 1881 Educational Times

In 1881, Donald MacAlister posed a problem in the Educational Times that remains relevant today. The problem centers on the statistical evidence for the effectiveness of a treatment based on a comparison between two proportions. A brief historical sketch is followed by a discussion of two default Bayesian solutions, one based on a one-sided test between independent rates, and one on a one-sided test between dependent rates. We demonstrate the current-day relevance of MacAlister’s original question with a modern-day example about the effectiveness of an educational program.
Association of Multimorbidity with Mortality and Healthcare Utilization in Chronic Kidney Disease

Chronic kidney disease (CKD) almost universally occurs in individuals with other medical problems. However, few studies have described CKD‐related multimorbidity using a framework that identifies chronic conditions as concordant (having overlap in treatment goals) versus discordant (having opposing treatment recommendations) and unrelated (having no overlap, but contributing to complexity via different resource requirements).
Compressive Sensing Imaging of 3-D Object by a Holographic Algorithm

Existing 3-D compressive sensing (CS)-based millimeter-wave (MMW) imaging methods require a large-scale storage of the sensing matrix and immense computations owing to the high dimension matrix-vector model employed in the optimization. To overcome this shortcoming, we propose an efficient CS method based on a holographic algorithm for near-field 3-D MMW imaging. An interpolation-free holographic imaging algorithm is developed and used as a sensing operator, in lieu of the nominal sensing matrix typically used in CS iterative optimization procedures. In so doing, the problem induced by the large-scale sensing matrix is avoided. With no interpolations required, both the computational speed and the image quality can be improved. Simulation and experimental results are provided to demonstrate the performance of the proposed method in comparison with those of the $\omega K$ -based CS and the traditional Fourier-based imaging techniques.
12 Sensory systems and escape behavior

Despite being on opposite sides of the arms race, predators and prey share a common goal: detecting each other as early as possible. Early detection is important for prey so they can initiate their escape behavior and increase their chances of survival. Early detection is also important for predators so they can take advantage of the surprise factor and enhance the chances of prey capture. We can then expect selection pressures on the predator and prey sensory systems to enhance the chances of mutual detection (Cronin 2005). For example, the sand cricket filiform hairs, which detect air movements, are especially sensitive to the frequencies and velocities that its predators produce (Magal et al. 2006). We review, from a mechanistic perspective, how sensory system configuration can influence antipredator behavior. For the sake of space, we focus on the visual system of vertebrate prey (see also the electronic supplementary material for a discussion on other sensory modalities), but some of the fundamental ideas can be extended to other sensory modalities (e.g., Phelps 2007). Within the visual system, several dimensions have been implicated in the responses of prey to predators: configuration of the visual fields (the degree of visual coverage around the prey’s head), spatial visual resolution (visual acuity), temporal visual resolution (how fast the retina can process temporal changes in visual stimuli), the type and number of centers of acute vision in the retina (retinal specialization), visual contrast (ability to resolve a stimulus against the background), motion detection, etc. We will discuss the role of many of these visual dimensions in affecting the decision-making of prey under the risk of predation. This approach will allow us to draw attention to some sensory aspects that behavioral ecologists tend to inadvertently omit when designing and interpreting studies on antipredator behavior.
Observe and Look Further: Achieving Consistent Performance on Atari

Despite significant advances in the field of deep Reinforcement Learning (RL), today's algorithms still fail to learn human-level policies consistently over a set of diverse tasks such as Atari 2600 games. We identify three key challenges that any algorithm needs to master in order to perform well on all games: processing diverse reward distributions, reasoning over long time horizons, and exploring efficiently. In this paper, we propose an algorithm that addresses each of these challenges and is able to learn human-level policies on nearly all Atari games. A new transformed Bellman operator allows our algorithm to process rewards of varying densities and scales; an auxiliary temporal consistency loss allows us to train stably using a discount factor of $\gamma = 0.999$ (instead of $\gamma = 0.99$) extending the effective planning horizon by an order of magnitude; and we ease the exploration problem by using human demonstrations that guide the agent towards rewarding states. When tested on a set of 42 Atari games, our algorithm exceeds the performance of an average human on 40 games using a common set of hyper parameters. Furthermore, it is the first deep RL algorithm to solve the first level of Montezuma's Revenge.
Optimizing the Cost-Performance Tradeoff for Coflows Across Geo-Distributed Datacenters

For data analytics jobs running across geographically distributed datacenters, coflows have to go through the inter-datacenter network over relatively low bandwidth and high cost links. In this case, optimizing cost-performance tradeoffs for such coflows becomes crucial. Ideally, decreasing the coflow completion time (CCT) can significantly improve the network performance, meanwhile, reducing the transmission cost introduced by these coflows is another fundamental goal for datacenter operators. Unfortunately, minimizing both the CCT and the transmission cost are conflicting objectives that cannot be achieved concurrently. Prior methods have significant limitations when exploring such tradeoffs, because they either merely decrease the average CCT or reduce the transmission cost independently. In this paper, we focus on a cost-performance tradeoff problem for coflows running across the inter-datacenter network. Specifically, we formulate an optimization problem, so as to minimize a combination of both the average CCT and the average transmission cost. This problem is inherently hard to solve due to the unknown information of future coflows. Therefore, we present Lever, an online coflow-aware optimization framework, to balance these two conflicting objectives. Without any prior knowledge of future coflows, Lever has been proved to have a non-trivial competitive ratio in solving this cost-performance tradeoff problem. Results from large-scale simulations demonstrate that Lever can significantly reduce the average transmission cost, and at the same time, speed up the completion of these coflows, compared with the state-of-the-art solutions.
How Important Is a Neuron?

The problem of attributing a deep network's prediction to its \emph{input/base} features is well-studied. We introduce the notion of \emph{conductance} to extend the notion of attribution to the understanding the importance of \emph{hidden} units. Informally, the conductance of a hidden unit of a deep network is the \emph{flow} of attribution via this hidden unit. We use conductance to understand the importance of a hidden unit to the prediction for a specific input, or over a set of inputs. We evaluate the effectiveness of conductance in multiple ways, including theoretical properties, ablation studies, and a feature selection task. The empirical evaluations are done using the Inception network over ImageNet data, and a sentiment analysis network over reviews. In both cases, we demonstrate the effectiveness of conductance in identifying interesting insights about the internal workings of these networks.
Effect of More vs Less Frequent Follow-up Testing on Overall and Colorectal Cancer–Specific Mortality in Patients With Stage II or III Colorectal Cancer: The COLOFOL Randomized Clinical Trial

Importance Intensive follow-up of patients after curative surgery for colorectal cancer is common in clinical practice, but evidence of a survival benefit is limited. Objective To examine overall mortality, colorectal cancer–specific mortality, and colorectal cancer–specific recurrence rates among patients with stage II or III colorectal cancer who were randomized after curative surgery to 2 alternative schedules for follow-up testing with computed tomography and carcinoembryonic antigen. Design, Setting, and Participants Unblinded randomized trial including 2509 patients with stage II or III colorectal cancer treated at 24 centers in Sweden, Denmark, and Uruguay from January 2006 through December 2010 and followed up for 5 years; follow-up ended on December 31, 2015. Interventions Patients were randomized either to follow-up testing with computed tomography of the thorax and abdomen and serum carcinoembryonic antigen at 6, 12, 18, 24, and 36 months after surgery (high-frequency group; n = 1253 patients) or at 12 and 36 months after surgery (low-frequency group; n = 1256 patients). Main Outcomes and Measures The primary outcomes were 5-year overall mortality and colorectal cancer–specific mortality rates. The secondary outcome was the colorectal cancer–specific recurrence rate. Both intention-to-treat and per-protocol analyses were performed. Results Among 2555 patients who were randomized, 2509 were included in the intention-to-treat analysis (mean age, 63.5 years; 1128 women [45%]) and 2365 (94.3%) completed the trial. The 5-year overall patient mortality rate in the high-frequency group was 13.0% (161/1253) compared with 14.1% (174/1256) in the low-frequency group (risk difference, 1.1% [95% CI, −1.6% to 3.8%]; P = .43). The 5-year colorectal cancer–specific mortality rate in the high-frequency group was 10.6% (128/1248) compared with 11.4% (137/1250) in the low-frequency group (risk difference, 0.8% [95% CI, −1.7% to 3.3%]; P = .52). The colorectal cancer–specific recurrence rate was 21.6% (265/1248) in the high-frequency group compared with 19.4% (238/1250) in the low-frequency group (risk difference, 2.2% [95% CI, −1.0% to 5.4%]; P = .15). Conclusions and Relevance Among patients with stage II or III colorectal cancer, follow-up testing with computed tomography and carcinoembryonic antigen more frequently compared with less frequently did not result in a significant rate reduction in 5-year overall mortality or colorectal cancer–specific mortality. Trial Registration clinicaltrials.gov Identifier: NCT00225641
Retrospective autopsy based study of fatal road traffic accidents in Fiji

Objective: To describe the demographic profile and distribution of injuries from autopsy cases due to fatal Road Traffic Accidents (RTA) in Fiji. Methods: This is a retrospective autopsy based study consisting of 102 medico-legal autopsies performed by the Fiji Institute of Forensic Science, Fiji Police Force during the period of two calendar years from January 1st 2011 to December 31st 2012. Results: Out of the 1454 medico-legal autopsies performed during the study period, 102 (7%) were due to fatal RTA. There were 72 (70.5%) males and 30 (29.5%) female fatalities with an overall male and female ratio of 2.3:1 and the 30 to 44 years age group showed highest number of victims of 30 (29.4%). The months of October in 2011 and August in 2012 took the maximum toll of road traffic deaths of 9 (8.8%) and 12 (11.6%) respectively. The highest number within the road user group were the passengers of 53 (51.9%) followed by the pedestrians and drivers of 32 (31.2%) and 16 (15.6%) respectively. Human behavioural errors or factors by all the road users of 95 (93.1%) was the highest contributing factor and pre-hospital mortality was most common, particularly road traffic death at the scene (51.9%) and those whilst en route to hospital (29.4%). Highest number of injuries were head injuries of 67 (65.7%), followed by multiple injuries of 57 (55.6%), thoracic injuries of 56 (54.9%), abdominal injuries of 31 (30.3%), vertebral injuries 21 (20.5%) and major vessel injuries of 12 (11.7%). The most common mechanism of death was haemorrhagic shock of 90 (88.2%) followed by asphyxia of 7 (6.8%), arrhythmias of 3 (2.9%) and finally septic shock of 2 (1.9%). Conclusion: This study emphasizes the need for better pre-hospital and hospital trauma management, improved traffic law enforcement, effective traffic related and health policy creation, and the establishment of a national traffic traumatic injury surveillance registry in Fiji.
tRNA fragments (tRFs) guide Ago to regulate gene expression post-transcriptionally in a Dicer-independent manner

tRNA related RNA fragments (tRFs), also known as tRNA-derived RNAs (tdRNAs), are abundant small RNAs reported to be associated with Argonaute proteins, yet their function is unclear. We show that endogenous 18 nucleotide tRFs derived from the 3′ ends of tRNAs (tRF-3) post-transcriptionally repress genes in HEK293T cells in culture. tRF-3 levels increase upon parental tRNA overexpression. This represses target genes with a sequence complementary to the tRF-3 in the 3′ UTR. The tRF-3-mediated repression is Dicer-independent, Argonaute-dependent, and the targets are recognized by sequence complementarity. Furthermore, tRF-3:target mRNA pairs in the RNA induced silencing complex associate with GW182 proteins, known to repress translation and promote the degradation of target mRNAs. RNA-seq demonstrates that endogenous target genes are specifically decreased upon tRF-3 induction. Therefore, Dicer-independent tRF-3s, generated upon tRNA overexpression, repress genes post-transcriptionally through an Argonaute-GW182 containing RISC via sequence matches with target mRNAs.
Nitrogen and carbon uptake kinetics and the influence of irradiance for a red tide bloom off southern California

The kinetics of nitrogen (nitrate, ammonium, urea) and carbon uptake by a red tide bloom consisting almost exclusively of the dinoflagellate Lingulodinium polyedrum (Stein) Dodge were determined with "Nand 13C-tracer techniques, as a function of substrate concentration (for nitrogen) and irradiance (for both carbon and nitrogen). Samples were collected from Newport Beach, California, in late March 1995, during a massive red tide bloom which occurred off the California coast. At the collection site, surface concentrations of L. polyedrum reached 1 1 X 106 cells 1-', with chlorophyll a = 125 pg 1-l. Maximal uptake rates of urea-N were approximately twice the maximal rates for either ammonium or nitrate during both the uptake versus substrate and uptake versus irradiance expenments, and the affinity for nitrate was much greater than previously demonstrated: half-saturation constant (K,) = 0.47 pg-at N 1-'. Carbon and nitrogen uptake rates as a function of irradiance were well described by a 3-parameter P versus E relationship (photosynthesis vs irradiance) proposed by Platt & Gallegos (1980), although dark-uptake of nitrogen compounds accounted for ca 50% of V,,,,,. These results demonstrate that L. polyedrum is capable of utilizing a broad range of both nitrogen concentrations and hght fluences, and that urea could potentially provide a large percentage of the nitrogen demand at ambient urea concentrations and across the entire spectrum of hght fluences. These data represent a more complete quantification of the N uptake dynamics of thls bloom-formlng species and contrast markedly compared to previous studies of L. polyedrum.
Lagoa Santa's contribution to the origins and life of early Americans

The region of Lagoa Santa, Central‐Eastern Brazil, provides an exceptional archeological record about Late Pleistocene/Early Holocene occupation of the Americas. Since the first interventions made by the Danish naturalist Peter Lund in the 19th century, hundreds of human skeletons have been exhumed in the region. These skeletons are complemented by a rich botanic, faunal, technological, and geomorphological archeological record. We explore here the contributions of Lagoa Santa material to the origins and lifestyle of early Americans, providing an historic background. Cranial morphology of Lagoa Santa skeletons allowed the proposition of a model of two biological components for the occupation of the Americas, in which early Americans are morphologically similar to people of African and Australo‐Melanesian origin. Furthermore, the archeological record in the region has revealed an intense use of plant resources, a restricted spatial distribution, and the symbolic elaboration of local hunter‐gatherers, unveiling a distinct lifestyle compared to early North American populations.
Synsacra of the Eocene Antarctic penguins : new data on spinal maturation and an insight into their role in the control of walking

The synsacrum is an important element of the axial skeleton in birds, both volant and flightless. Little is known about the maturation of this complex bone in penguins. In this work, the supposedly ontogenetically youngest known synsacrum of early penguins was described. The analysis of this specimen, collected within the Eocene La Meseta Formation of Seymour (Marambio) Island, Antarctic Peninsula, revealed that this bird had attained at least the fledging stage of growth. Studies of three mature synsacra recovered from the same formation focused on the synsacral canals and, using indirect reasoning, their contents. These analyses revealed that the lumbosacral intumescence of the spinal cord and its exten− sions, the transverse canals, had been developed roughly like those in extant penguins (and also swifts and cormorants). The neural spine extensions (a non−nervous tissue) tracing the transverse grooves of the dorsal wall of the synsacral canal are currently considered as in− volved in the control of walking. The presented data suggest that such a sense organ gained its current penguin configuration by the late Eocene.