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The relationship between plant and butterfly biodiversity is altered by compound effects of human activities at landscape and regional scales
No full textUnderstanding how human activities influence biodiversity is a pressing challenge. Here, we ask whether obligate biotic interactions between plants and butterflies respond to patterns in anthropogenic disturbance at landscape and regional scales. Here, we used hierarchical models to understand how the relationships between alpha and beta taxonomic diversities of butterflies and plants change across landscapes and regions exposed to a gradient of anthropogenic influence. Analyzing 1682 sampling sites in which butterfly and plant species were both inventoried, from 45 studies identified through a literature review, we found that ecological communities sampled in highly disturbed areas displayed a lower number of butterfly species per plant species, and more homogenized butterfly communities. These responses were exacerbated when human activities affected both the landscape and the region hosting the plant and butterfly communities assessed. Our results suggest that human activities can differentially affect butterflies and plants, two co-evolved groups, thus altering long-term eco-evolutionary dynamics. They also hint at how the negative effects of human activities on biodiversity compound between landscape and regional scales, illustrating the importance of multi-scale analyses and approaches for understanding and protecting biodiversity globally.</p
Effects of expectation, attention, and NMDA receptor blockade on feedforward and feedback processing
No full textPerception is increasingly viewed as an inferential process wherein sensory inputs are integrated with prior expectations. We employed time-resolved decoding on electroencephalography (EEG) data (n = 30 male participants) to investigate how expectations modulate sensory processing across varying levels of stimulus complexity, and tested the effect of attention and NMDA receptor blockade. We designed a visual stimulus containing features of different complexity whose processing relies on distinct neural mechanisms: local contrast, collinearity, and the Kanizsa illusion, involving primarily feedforward, lateral, and feedback processes, respectively. EEG decoding revealed that expectations modulated lateral and feedback processing (better decoding for unexpected stimuli) but not feedforward processing. These expectation effects were confined to attended (task-relevant) features and were not observed for task-irrelevant features. The NMDA receptor antagonist memantine selectively enhanced decoding of the Kanizsa illusion, implicating NMDA-mediated feedback mechanisms in perceptual inference, but it did not modulate the effects of expectation or attention. These findings highlight the differential impact of expectations across different stages of sensory processing and reveal a distinct role of NMDA receptor-mediated feedback mechanisms. Significance statement Perception integrates sensory inputs with prior expectations. Using EEG decoding, we examined how expectations shape sensory processing at different levels of complexity and tested the effects of attention and NMDA receptor blockade. Our visual stimuli were designed to capture EEG markers of feedforward, lateral, and feedback mechanisms. Expectations influenced lateral and feedback processing (better decoding for unexpected stimuli) but not feedforward processing, and these effects were selective to task-relevant stimulus features. Memantine, an NMDA receptor antagonist, selectively improved decoding of the Kanizsa illusion, implicating NMDA-mediated feedback in perceptual integration, but it did not shape expectation or attention effects
Characterization of the brain lipidome associated with frontotemporal lobar degeneration MAPT P301S mutation
No full textMutations in microtubule-associated protein Tau (MAPT), the gene that codes for the protein Tau, cause frontotemporal lobar degeneration (FTLD) with phenotypes ranging from behavioral changes to cognitive impairment and parkinsonism. Recently, lipid changes have been heavily implicated in synucleinopathies and secondary tauopathies such as Alzheimer's disease. Whether mutations in MAPT or accumulation of hyperphosphorylated Tau (pTau) can contribute to lipid changes in primary tauopathies is unknown. Here, we examine the effect of the FTLD-associated mutation MAPT P301S on brain lipid metabolism in a Tau transgenic mouse model. We find that the MAPT P301S mutation drives increased levels of diglycerides and hexosylceramides and lactosylceramides while reducing triglycerides, specifically those triglyceride species containing monounsaturated fatty acids, but does not affect cholesterol metabolism prior to pTau accumulation. Strikingly, with increasing accumulation of pTau, neutral lipids such as cholesteryl esters and triglycerides start to accumulate in the brain of mutant mice, as also reported in the Alzheimer's disease and FTLD brain. Furthermore, with increasing buildup of pTau, we observe decreased cholesterol synthesis and turnover to 24S-hydroxycholesterol. Overall our data indicates that the MAPT P301S mutation and accumulation of pTau are associated with distinct brain lipidomes in vivo.</p
Pushing Boundaries: Domestic Courts and Legislatures as the New Laboratory for War Crimes Law
No full textUncovering Transient Execution Vulnerabilities: Catalysts For Exploitation On Modern Processors
No full textModern processors, engineered for maximum performance, have adopted complex microarchitectural features such as speculative and out-of-order execution. These optimizations, while delivering substantial speedups, have directly enabled a new class of security vulnerabilities: transient execution attacks. Attacks like Spectre and Meltdown exploit these very features, allowing adversaries to bypass architectural security boundaries and exfiltrate sensitive data through microarchitectural side channels. The emergence of these vulnerabilities has fundamentally redefined system security. Early research and industry responses—such as speculation barriers and microcode updates—focused on mitigating specific Spectre and Meltdown variants. However, it is now evident that transient execution vulnerabilities are far more pervasive and intricate than initially recognized. The core issue lies in the disconnect between the architectural guarantees of processors and the exploitable realities of their microarchitectures. This thesis systematically exposes and analyzes a wide spectrum of classes of transient execution vulnerabilities. The complexity of modern CPUs, coupled with evolving software abstractions, has created a landscape rife with novel attack vectors that span every layer of the computing stack. Addressing these threats demands not only the identification of new vulnerabilities but also the development of robust methodologies for their analysis and mitigation across all abstraction levels. To achieve this, the thesis rigorously investigates transient execution vulnerabilities from multiple angles. At the software level, it demonstrates how operating system mechanisms—such as synchronization primitives—are compromised by speculative execution, revealing previously overlooked attack surfaces. At the architecture-microarchitecture boundary, it uncovers how violations of architectural invariants give rise to new transient execution threats. The research further dissects the microcode of complex instructions, exposing for the first time ever transient cross-core leakage even in the presence of all conventional defenses. At the hardware design stage, it introduces directed fuzzing techniques that proactively and automatically detect instances of this class of vulnerabilities before chip design reaches production. The contributions of this work are organized around four comprehensive re- search papers, each targeting a distinct abstraction level: software-level vulnerabili- ties in synchronization primitives in GhostRace (Chapter 2), microarchitectural violations of architectural invariants in Rage Against the Machine Clear (Chap- ter 3), transient cross-core leakage via microcode and off-core instructions in CrossTalk (Chapter 4), and hardware design-level detection using directed fuzzing in BugsBunny (Chapter 5). Collectively, these research papers establish that deep microarchitectural optimizations such as transient execution can be identified and exploited across all abstraction layers, demanding holistic solutions that span the entire computing stack. This thesis also charts clear directions for future research to mitigate, detect, and prevent these vulnerabilities. In the short-term, advancing software gadget discovery and exploitability analysis will systematically eliminate code patterns exploitable by transient execution attacks from existing software running on existing vulnerable processors. While in the long-term, first, developing robust microarchitectural domain isolation will sharply curtail data leakage across microarchitectural security domain boundaries. Second, enhancing pre-silicon design fuzzing will ensure that instances of this class of vulnerabilities are caught early in the hard- ware lifecycle and fixed before tape out. Finally, integrating AI-driven verification into chip design will automate and scale the detection of subtle hardware design security flaws, providing a proactive defense against not only transient execution vulnerabilities, but also emerging hardware-design security threats. In summary, this thesis provides a comprehensive perspective on how transient execution vulnerabilities arise and can be exploited throughout the computing stack. By connecting insights from both software and hardware domains, it aims to contribute to a deeper understanding of these challenges and to offer practical approaches for improving the security of modern systems against this important class of vulnerabilities of the last decade
The Untapped Potential of Food Webs in Systematic Conservation Planning
No full textInternational conservation policy includes the dual aims of protecting biodiversity and nature's contributions to people (NCP). Achieving these goals requires protecting not only species and habitats but also the networks of biotic interactions that sustain them. Food webs, which represent predator-prey interactions between species, are increasingly recognised as a link between ecosystem structure, function, and resilience, which are concepts that are frequently cited in conservation policy. Yet, conservation planning and policy typically focus on individual species and habitats and overlook the interactions that support their persistence. We review the literature at the intersection of food web ecology and conservation, and highlight how food webs can inform three conservation goals: preventing species extinctions, maintaining ecosystem functions and NCP, and fostering ecosystem resilience. Food web data and metrics, such as interaction diversity, trophic diversity, connectance, or modularity, can be used to prioritize species that are key to ecosystem structure and functioning, and to guide spatial prioritization to protect functionally diverse and resilient communities. Given the growing availability of food web data, incorporating food webs in conservation planning can lead to more effective and resilient conservation outcomes that sustain biodiversity and ecosystem functions in the long term.</p
How many points converge to a heteroclinic network in an aperiodic way?
No full textHomoclinic and heteroclinic connections can form cycles and networks in phase space, which organize global phenomena in dynamical systems. On the one hand, stability notions for (omni)cycles give insight into how many initial conditions approach the network along a single given (omni)cycle. On the other hand, the term switching is used to describe situations where there are trajectories that follow any possible sequence of heteroclinic connections along the network. Here we give a notion of asymptotic stability for general sequences along a network of homoclinic and heteroclinic connections. We show that there cannot be uncountably many aperiodic sequences that attract a set with nontrivial measure. Finally, we discuss examples where one may or may not expect aperiodic convergence towards a network and conclude with some open questions.</p
Let Earth Receive Her King:Six Christmas Sermons Picturing God
No full textThis article offers a qualitative analysis of six Christmas sermons from the Christian Reformed Churches in the Netherlands, focusing on their picturing of God. The analysis sheds light on the nature of the knowledge of God conveyed in the sermons and demonstrates that the homiletic theology expressed in preaching offers constructive insight into the image of God.By emphasising divine kingship and relational engagement, the sermons picture God as both sovereign and benevolent. Verbs play a more significant role than traditional attributes in offering insight into the image of God in these sermons. While Jesus is affirmed as divine, there is minimal metaphysical reflection. By emphasising the divinity of Jesus and God’s independent actions in history, the sermons offer subtle criticism on contemporary views of God as evidenced by sociological research in Western society. God as pictured in the sermons is also not solely focused on individual well-being. God’s kingship is presented with a critical attitude towards those in power. This ensures that the sermons remain connected to 21st-century thinking about kingship. Most sermons picture a God who is only marginally interested in contemporary social issues. This questions the sermons’ fundamental proclamation that God is in control of all things and encourages homiletic reflection on the use of images in sermons. Contribution: This article contributes to making homiletic theology more visible in sermons by providing a qualitative analysis of six sermons, with particular attention to the picturing of God. The findings aim to increase homileticians’ sensitivity to the verbs and imagery employed in sermons, encouraging deeper reflection on their relationship to both tradition andcontemporary culture