APOE2 is associated with longevity independent of Alzheimer’s disease

Although the ε2 allele of apolipoprotein E (APOE2) benefits longevity, its mechanism is not understood. The protective effects of the APOE2 on Alzheimer’s disease (AD) risk, particularly through their effects on amyloid or tau accumulation, may confound APOE2 effects on longevity. Herein, we showed that the association between APOE2 and longer lifespan persisted irrespective of AD status, including its neuropathology, by analyzing clinical datasets as well as animal models. Notably, APOE2 was associated with preserved activity during aging, which also associated with lifespan. In animal models, distinct apoE isoform levels, where APOE2 has the highest, were correlated with activity levels, while some forms of cholesterol and triglycerides were associated with apoE and activity levels. These results indicate that APOE2 can contribute to longevity independent of AD. Preserved activity would be an early-observable feature of APOE2-mediated longevity, where higher levels of apoE2 and its-associated lipid metabolism might be involved.

Post-merger chirps from binary black holes as probes of the final black-hole horizon

The merger of a binary black hole gives birth to a highly distorted final black hole. The gravitational radiation emitted as this black hole relaxes presents us with the unique opportunity to probe extreme gravity and its connection with the dynamics of the black hole horizon. Using numerical relativity simulations, we demonstrate a connection between a concrete observable feature in the gravitational waves and geometrical features on the dynamical apparent horizon of the final black hole. Specifically, we show how the line-of-sight passage of a “cusp”-like defect on the horizon of the final black hole correlates with “chirp”-like frequency peaks in the post-merger gravitational-waves. These post-merger chirps should be observed and analyzed as the sensitivity of LIGO and Virgo increase and as future generation detectors, such as LISA and the Einstein Telescope, become operational.

APOE2 promotes longevity independent of Alzheimer’s disease

ObjectiveAlthough apolipoprotein E (APOE) allele associates with longevity, its mechanism is not understood. The protective effects of APOE2 and the deleterious effects of APOE4 on Alzheimer’s disease (AD) risk may confound APOE effects on longevity.MethodsWe analyzed a large number of subjects from the National Alzheimer’s Coordinating Center (NACC), and animal models expressing human apoE isoforms in the absence of AD.ResultsClinically, the APOE2 allele was associated with longer lifespan, while APOE4 associated with shorter lifespan, compared to the common APOE3 allele. This effect was also seen irrespective of clinical AD status, and in subjects with little amyloid pathology or after adjustment for AD-related pathologies. In animal studies, apoE2-TR mice also exhibited longer lifespan, while apoE4 showed some trends of shorter lifespan. Notably, old apoE2-TR mice kept activity measured by open field assay, associated with longer lifespan. Evidence of preserved activity in APOE2 carrier was also obtained in clinical records. In animal studies, higher levels of apoE2 in brain and plasma were correlated with activity. Moreover, lower levels of total cholesterol in the brain and higher levels of high-density lipoprotein cholesterol and triglycerides in the plasma of apoE2-TR mice were associated with apoE levels and more activity.InterpretationAPOE2 can contribute to longevity independent of AD. Preserved activity would be an early-observable feature of apoE2-mediated longevity, where higher levels of apoE2 and its-associated lipid metabolism might be involved.

The σ-bump in elliptical galaxies – a signature of major mergers?

The stellar radial velocity dispersion profiles of elliptical galaxies can be well described by a power-law σ(r)∝r−β. We analyze a set of elliptical galaxies formed by major mergers of isolated disk galaxies with mass ratios of 1:1 and 3:1 for several orbital configurations (Johansson et al. 2009). The galaxies in our sample show a deviation from the power-law at 1 − 3Reff, which we term the σ-bump (Schauer et al. 2014). This feature is most prominent in remnants of 1:1 mergers and weakens for remnants of mergers with smaller mass ratios, indicating that the σ-bump is a signature of an equal mass merger. The σ-bump does not vanish with time but stays constant once it has formed, in contrast to shells. It can be seen under all projections, making it an observable feature in the outskirts of elliptical galaxies. We indeed identify three possible σ-bump candidates in the sample of 12 SLUGGS-survey ellipticals studied by Pota et al. (2013), who use globular clusters as tracers for the outer stellar halos (see Schauer et al. 2014, for more details). For further comparisons, we here provide for the first time a two dimensional map of the velocity dispersion of one simulated σ-bump galaxy, to identify the σ-bump in observations of kinematic maps out to several Reff. The σ-bump appears as a global ring-like feature if seen face-on and as an extended box-like feature in its edge-on projection.

Translating structural pause in the Qur’an

This study aims to investigate the translation of syntactic pause as an under-researched linguistic observable feature from Arabic into English, with particular reference to Qur’anic examples. Due to the lack of studies in this area, and because the phenomenon has not been treated sufficiently in Qur’anic and non-Qur’anic discourses, Qur’anic verses illustrating the point are sampled, analyzed and discussed so as to uncover the difficulties and to suggest translation solutions. A handful of authentic and authoritative Qur’anic exegeses are consulted, in addition to three translations of the Qur’an, in an attempt to explore the role such interpretations can play in rendering the possible syntactic meanings into English. This makes it possible to provide a solid syntactic-translational ground for assigning syntactic-semantic value to the pause in the selected examples. This also allows the author to point out the problematic aspect of this linguistic phenomenon, where two acceptable readings of one syntactic structure can emerge. This study demonstrates that syntactic pause in the Qur’an presents certain challenges for the translator and requires great effort to render faithfully in the target language. The study also suggests how immediate and broader contexts can guide the translator in prioritizing one interpretation over another

Subgrain boundaries and related microstructural features in EDML (Antarctica) deep ice core

Subgrain boundaries revealed as shallow sublimation grooves on ice sample surfaces are a direct and easily observable feature of intracrystalline deformation and recrystallization. Statistical data obtained from the EPICA Dronning Maud Land (EDML) deep ice core drilled in East Antarctica cannot detect a depth region of increased subgrain-boundary formation. Grain-boundary morphologies show a strong influence of internal strain energy on the microstructure at all depths. The data do not support the classical view of a change of dominating recrystallization regimes with depth. Three major types of subgrain boundaries, reflecting high mechanical anisotropy, are specified in combination with crystal-orientation analysis.

Altruists with Green Beards: Still Kicking?

In earlier work, I proposed the ‘adaptive standard of rationality’, according to which narrow self-interest models can be broadened by positing additional tastes, but only upon a plausible showing that those tastes do not hamper resource acquisition in competitive environments. This proposal is related to the green beard hypothesis from biology, according to which altruism might be adaptive if its presence could be reliably signaled by some observable feature, such as a green beard. In their contribution to this issue Ernst Fehr and Urs Fischbacher offer theoretical arguments and describe laboratory experiments whose results they interpret as refuting my version of the green beard hypothesis. In this response, I argue that their theoretical arguments and experimental evidence pose no threat to the green beard hypothesis.

ON OBSERVABILITY OF 3D CONTINUOUS-TIME AUTONOMOUS CHAOTIC SYSTEMS BASED ON SCALAR OUTPUT MEASUREMENT

In this paper, by means of case studies we discuss an observable feature of 3D continuous-time autonomous chaotic systems through scalar output and its time derivatives. We observe that the Lorenz system, the Rössler system, the Chua circuit and the Chen system are all observable based on scalar output and its derivatives. This leads to our conjecture that chaotic motion described by 3D continuous-time autonomous dynamical system is observable based on a scalar output and its first- and second-order derivatives. Finally, we present some mathematical analysis and put up some theoretical questions for future studies.