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Oct 14, 2024

Magnetic fields and electric currents around the dayside magnetopause as inferred from data-constrained modeling

Posted by in category: mathematics

Based on a new mathematical framework and large multi-year multi-mission data sets, we reconstruct electric currents and magnetic fields around the dayside magnetopause and their dependence on the incoming solar wind, IMF, and geodipole tilt. The model architecture builds on previously developed mathematical frameworks and includes two separate blocks: for the magnetosheath and for the adjacent outer magnetosphere. Accordingly, the model is developed in two stages: 1) reconstruction of a best-fit magnetopause and underlying dayside magnetosphere, based on a simple shielded configuration, and 2) derivation of the magnetosheath magnetic field, represented by a sum of toroidal and poloidal terms, each expanded into spherical harmonic series of angular coordinates and powers of normal distance from the boundary. The spacecraft database covers the period from 1995 through 2022 and is composed of data from Geotail, Cluster, Themis, and MMS, with the total number of 1-min averages about 3 M. The modeling reveals orderly patterns of the IMF draping around the magnetosphere and of the magnetopause currents, controlled by the IMF orientation, solar wind pressure, and the Earth’s dipole tilt. The obtained results are discussed in terms of the magnetosheath flux pile-up and the dayside magnetosphere erosion during periods of northward or southward IMF, respectively.

The dayside magnetosheath and magnetopause play a principal role in the magnetosphere response to the interplanetary plasma flow. They serve as a main gateway where the first contact occurs between the incoming magnetized solar wind and the geomagnetic field, eventually resulting in a complex chain of magnetospheric processes. Of primary importance here is the mutual orientation of the external IMF and the internal magnetospheric field, defining the reconnection pattern at the boundary. This subject has long been at the center of many studies and extensive debates in the literature, starting from the seminal ideas of Dungey (Dungey, 1961) and followed by a multitude of works, recently summarized in reviews (Trattner et al., 2021; Fuselier et al., 2024). The reconnection geometry has been traditionally addressed in the framework of two basic concepts: the component and antiparallel merging (e.g. (Fuselier et al., 2021), and refs. therein (Qudsi et al., 2023)).

Oct 14, 2024

Critical Veeam Vulnerability Exploited to Spread Akira and Fog Ransomware

Posted by in category: cybercrime/malcode

Cybercriminals exploit CVE-2024–40711 in Veeam to deploy ransomware, targeting unpatched systems and compromised VPNs.

Oct 14, 2024

OilRig Exploits Windows Kernel Flaw in Espionage Campaign Targeting UAE and Gulf

Posted by in category: futurism

OilRig exploits a Windows kernel flaw in a cyber espionage campaign targeting UAE networks, leveraging backdoors and privilege escalation.

Oct 14, 2024

FBI Creates Fake Cryptocurrency to Expose Widespread Crypto Market Manipulation

Posted by in category: cryptocurrencies

U.S. DoJ charges 18 in a $25M cryptocurrency fraud operation, uncovering market manipulation through an FBI-led sting.

Oct 14, 2024

GitHub, Telegram Bots, and ASCII QR Codes Abused in New Wave of Phishing Attacks

Posted by in categories: cybercrime/malcode, law enforcement, robotics/AI

“This makes the scam much harder to spot, as the information provided is personally relevant to the victims, arrives via the expected communication channel, and the linked, fake websites look as expected.”

What’s more, the diversification of the victimology footprint has been complemented by improvements to the toolkit that allow the scammer groups to speed up the scam process using automated phishing page generation, improve communication with targets via interactive chatbots, protecting phishing websites against disruption by competitors, and other goals.

Telekopye’s operations have not been without their fair share of hiccups. In December 2023, law enforcement officials from Czechia and Ukraine announced the arrest of several cybercriminals who are alleged to have used the malicious Telegram bot.

Oct 14, 2024

Can walls of oysters protect shores against hurricanes? DARPA wants to know

Posted by in category: climatology

Colonized artificial reef structures could absorb the power of storms.

Oct 14, 2024

Webb Telescope Unveils an Early Universe Galaxy Growing From the Inside Out

Posted by in category: cosmology

Using the James Webb Space Telescope, astronomers have for the first time observed a galaxy in the early universe growing from the inside out, a mere 700 million years after the Big Bang.

This galaxy, significantly smaller yet more mature than expected, demonstrates unique growth patterns with its dense core and rapidly forming star outskirts.

Astronomers have employed the NASA /ESA James Webb Space Telescope (JWST) to observe the ‘inside-out’ growth of a galaxy in the early universe, a mere 700 million years after the Big Bang.

Oct 14, 2024

Frontiers: Neuromodulatory inputs from brainstem systems modulate the normal function of spinal motoneurons by altering the activation properties of persistent inward currents (PICs) in their dendrites

Posted by in category: biotech/medical

However, the effect of the PIC on firing outputs also depends on its location in the dendritic tree. To investigate the interaction between PIC neuromodulation and PIC location dependence, we used a two-compartment model that was biologically realistic in that it retains directional and frequency-dependent electrical coupling between the soma and the dendrites, as seen in multi-compartment models based on full anatomical reconstructions of motoneurons. Our two-compartment approach allowed us to systematically vary the coupling parameters between the soma and the dendrite to accurately reproduce the effect of location of the dendritic PIC on the generation of nonlinear (hysteretic) motoneuron firing patterns. Our results show that as a single parameter value for PIC activation was either increased or decreased by 20% from its default value, the solution space of the coupling parameter values for nonlinear firing outputs was drastically reduced by approximately 80%. As a result, the model tended to fire only in a linear mode at the majority of dendritic PIC sites. The same results were obtained when all parameters for the PIC activation simultaneously changed only by approximately ±10%. Our results suggest the democratization effect of neuromodulation: the neuromodulation by the brainstem systems may play a role in switching the motoneurons with PICs at different dendritic locations to a similar mode of firing by reducing the effect of the dendritic location of PICs on the firing behavior.

Spinal motoneurons have large, highly branched dendrites and voltage-gated ion channels that generate strong persistent inward currents (PICs) (Schwindt and Crill, 1980). Over the past 30 years, the impact of PICs on the firing output of the motoneurons has been extensively investigated in various species, including turtles (Hounsgaard and Kiehn, 1985, 1989), rats (Bennett et al., 2001; Li and Bennett, 2003), mice (Carlin et al., 2000; Meehan et al., 2010) and cats (Lee and Heckman, 1998, 1999). There has been a consensus in the motoneuron physiology community that in the presence of monoamines (i.e., norepinephrine and serotonin), the activation of the L-type Ca2+ PIC channels is facilitated, producing a long-lasting membrane depolarization (i.e., plateau potential) (reviewed in Powers and Binder, 2001; Heckman et al., 2008).

Oct 14, 2024

Illusionism and types of physicalism

Posted by in category: neuroscience

Can we in principle ever deduce the mental from the physical?

Christopher Devlin Brown and David Papineau have a new paper out in the Journal of Consciousness Studies titled: Illusionism and A Posteriori Physicalism; No Fact of the Matter. (Note: the link is to a free version.) As the title makes clear, the overall gist is that the difference between illusionism and a posteriori physicalism amounts to a definitional dispute.

A quick primer. Illusionism is the stance that consciousness exists, but only in the sense of functional capabilities such as modeling the self in its environment, attention, learning, episodic memory, self monitoring, etc. What’s thought to be illusory is phenomenal consciousness, the “what it’s like” nature of subjective experience, but particularly in the strong sense as something distinct from functional capabilities, and with properties, such as fundamental subjectivity, that imply it’s non-physical.

Oct 14, 2024

Susan Blackmore’s illusionism

Posted by in category: neuroscience

Susan Blackmore’s Consciousness: A Very Short Introduction may have been the first book I read on consciousness many years ago. Recent conversations rekindled my interest in her views.

I’m pretty sure her discussion of consciousness as an illusion was the first time I had encountered that idea. Strong illusionists such as Keith Frankish and Daniel Dennett generally take the stance that phenomenal consciousness doesn’t exist. Blackmore’s illusionism seems like a weaker form, that consciousness exists but isn’t what it seems. And by “consciousness” she stipulates in one of her books that she usually means phenomenal consciousness.

Continue reading “Susan Blackmore’s illusionism” »

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