Miracle-dz/UniFAR-FTUs huggingface dataset:
Benchmarking the generalizability of brain age models: Challenges posed by scanner variance and prediction bias

Machine learning has been increasingly applied to neuroimaging data to predict age, deriving a personalized biomarker with potential clinical applications. The scientific and clinical value of these models depends on their applicability to independently acquired scans from diverse sources. Accordingly, we evaluated the generalizability of two brain age models that were trained across the lifespan by applying them to three distinct early‐life samples with participants aged 8–22 years. These models were chosen based on the size and diversity of their training data, but they also differed greatly in their processing methods and predictive algorithms. Specifically, one brain age model was built by applying gradient tree boosting (GTB) to extracted features of cortical thickness, surface area, and brain volume. The other model applied a 2D convolutional neural network (DBN) to minimally preprocessed slices of T1‐weighted scans. Additional model variants were created to understand how generalizability changed when each model was trained with data that became more similar to the test samples in terms of age and acquisition protocols. Our results illustrated numerous trade‐offs. The GTB predictions were relatively more accurate overall and yielded more reliable predictions when applied to lower quality scans. In contrast, the DBN displayed the most utility in detecting associations between brain age gaps and cognitive functioning. Broadly speaking, the largest limitations affecting generalizability were acquisition protocol differences and biased brain age estimates. If such confounds could eventually be removed without post‐hoc corrections, brain age predictions may have greater utility as personalized biomarkers of healthy aging.
RG-2 flow, mass and entropy

The RG-2 flow is the two-loop approximation for the world-sheet non-linear sigma model renormalization group flow. The first truncation of the flow is the well known Ricci flow, at two loops higher order curvature terms appear, changing almost completely the behaviour of the evolution equation. In this article we study the RG-2 flow in the context of general relativity. Contrary to what happens with the Ricci flow the RG-2 flow theory has not been studied exhaustively, and from a mathematical point of view there are big differences between both flows. Considering a time symmetric foliation of an asymptotically flat spacetime, we show that the area A of a closed two dimensional surface S is monotonous under the RG-2 flow, refining and extending the previous results already known for the Ricci flow. We show that the inequality that relates the area of the surface S and the Hawking mass, already found for the Ricci flow, is still satisfied when we make evolve the area under the new flow. Finally, we discuss about Perelman‘s W-entropy for the RG-2 flow and the physically motivated path towards the gradient formulation of the RG-2 flow.
Exponential Convergence and stability of Howards's Policy Improvement Algorithm for Controlled Diffusions

Optimal control problems are inherently hard to solve as the optimization must be performed simultaneously with updating the underlying system. Starting from an initial guess, Howard's policy improvement algorithm separates the step of updating the trajectory of the dynamical system from the optimization and iterations of this should converge to the optimal control. In the discrete space-time setting this is often the case and even rates of convergence are known. In the continuous space-time setting of controlled diffusion the algorithm consists of solving a linear PDE followed by maximization problem. This has been shown to converge, in some situations, however no global rate of is known. The first main contribution of this paper is to establish global rate of convergence for the policy improvement algorithm and a variant, called here the gradient iteration algorithm. The second main contribution is the proof of stability of the algorithms under perturbations to both the accuracy of the linear PDE solution and the accuracy of the maximization step. The proof technique is new in this context as it uses the theory of backward stochastic differential equations.
The accuracy of subhalo detection

With the ever increasing resolution of N-body simulations, accurate subhalo detection is becoming essential in the study of the formation of structure, the production of merger trees and the seeding of semi-analytic models. To investigate the state of halo finders, we compare two different approaches to detecting subhaloes; the first based on overdensities in a halo and the second being adaptive mesh refinement. A set of stable mock Navarro-Frenk-White (NFW) dark matter haloes was produced and a subhalo was placed at different radii within a larger halo. SUBFIND (a friends-of-friends based finder) and AHF (an adaptive mesh based finder) were employed to recover the subhalo. As expected, we found that the mass of the subhalo recovered by SUBFIND has a strong dependence on the radial position and that neither halo finder can accurately recover the subhalo when it is very near the centre of the halo. This radial dependence is shown to be related to the subhalo being truncated by the background density of the halo and originates due to the subhalo being defined as an overdensity. If the subhalo size is instead determined using the peak of the circular velocity profile, a much more stable value is recovered. The downside to this is that the maximum circular velocity is a poor measure of stripping and is affected by resolution. For future halo finders to recover all the particles in a subhalo, a search of phase space will need to be introduced.
THE CENTRAL ENGINES OF TWO UNUSUAL RADIO-INTERMEDIATE/QUIET ACTIVE GALACTIC NUCLEI: III Zw 2 AND PG 1407+265

We use the accretion disk/corona+jet model to fit the multi-band spectral energy distributions (SEDs) of two unusual radio-intermediate/quiet quasars. It is found that the optical/UV emission of III Zw 2 is probably dominated by the emission from the accretion disk. The X-ray emission should be dominated by the radiation from the jet, while the contribution of the disk corona is negligible. The optical/UV component in the SED of PG 1407+265 can be well modeled as the emission from the accretion disk, while the IR component is attributed to the thermal radiation from the dust torus with an opening angle of ∼50°. If the X-ray continuum emission is dominated by the synchrotron emission of the jet, the source should be a “high peak frequency blazar,” which obviously deviates from the normal blazar sequence. The observed SED can also be fitted quite well by the accretion disk/corona model with the viscosity parameter α = 0.5. The spectrum of the accretion disk/corona in PG 1407+265 satisfies the weak-line quasar criterion suggested in Laor & Davis.
Anomalous transport near the Lifshitz transition at the LaAlO 3 / SrTiO 3 interface

The two-dimensional electron liquid, at the (001) interface between band insulators ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$, undergoes Lifshitz transition as the interface is doped with carriers. At a critical carrier density, two additional orbitals populate at the Fermi level, with a concomitant change in the Fermi surface topology. Using dynamical mean-field theory, formulated within a realistic three-orbital model, we study the influence of the Lifshitz transition and local electron correlations on the transport properties. We look at the thermal conductivity, optical conductivity, Seebeck coefficient, and angle-resolved photoemission spectra and find that at a critical density, both the thermal and dc conductivities rise sharply to higher values while the Seebeck coefficient shows a cusp. The interorbital electron-electron interaction transfers spectral weight near the $\mathrm{\ensuremath{\Gamma}}$ point towards lower energy, thereby reducing the critical density. In the presence of external magnetic field, the critical density further reduces due to exchange splitting. Beyond a sufficiently large field, multiple cusps appear in the Seebeck coefficient revealing multiple Lifshitz transitions.
Superenhancer drives a tumor-specific splicing variant of MARCO to promote triple-negative breast cancer progression

Significance Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking targeted therapy. Since the transcript variation in TNBC remains unexplored, we performed systematic analysis of RNA splicing. We identified an oncogenic transcript, macrophage receptor with collagenous structure–tumor-specific transcript (MARCO-TST), which is specifically expressed in TNBC tumor cells and activates the hypoxia pathway. We also illustrated that BRD4-bound superenhancer drives the transcription of MARCO-TST. BET inhibitors result in sustained repression of MARCO-TST function and transcriptional activity. Our study provides a potential therapeutic strategy of TNBC to restrain MARCO-TST activity.
High dispersion spectroscopy of two A supergiant systems in the Small Magellanic Cloud with novel properties

We present the results of a spectroscopic investigation of two novel variable bright blue stars in the SMC, OGLE004336.91-732637.7 (SMC-SC3) and the periodically occulted star OGLE004633.76-731204.3 (SMC-SC4), whose photometric properties were reported by Mennickent et al. (2010). High-resolution spectra in the optical and far-UV show that both objects are actually A + B type binaries. Three spectra of SMC-SC4 show radial velocity variations, consistent with the photometric period of 184.26 d found in Mennickent et al. 2010. The optical spectra of the metallic lines in both systems show combined absorption and emission components that imply that they are formed in a flattened envelope. A comparison of the radial velocity variations in SMC-SC4 and the separation of the V and R emission components in the Hα emission profile indicate that this envelope, and probably also the envelope around SMC-SC3, is a circumbinary disc with a characteristic orbital radius some three times the radius of the binary system. The optical spectra of SMC-SC3 and SMC-SC4 show, respectively, He I emission lines and discrete blue absorption components (BACs) in metallic lines. The high excitations of the He I lines in the SMC-SC3 spectrum and the complicated variations of Fe II emission and absorption components with orbital phase in the spectrum of SMC-SC4 suggests that shocks occur between the winds and various static regions of the stars' corotating binary-disc complexes. We suggest that BACs arise from wind shocks from the A star impacting the circumbinary disc and a stream of former wind-efflux from the B star accreting on to the A star. The latter picture is broadly similar to mass transfer occurring in the more evolved (but less massive) ALGOL (B/A + K) systems, except that we envision transfer occurring in the other direction and not through the inner Lagrangian point. Accordingly, we dub these objects prototype of a small group of Magellanic Cloud wind-interacting A + B binaries.
$\operatorname{GL}_{2}\mathbb{R}$ orbit closures in hyperelliptic components of strata

The object of this paper is to study GL(2,R) orbit closures in hyperelliptic components of strata of abelian differentials. The main result is that all higher rank affine invariant submanifolds in hyperelliptic components are branched covering constructions, i.e. every translation surface in the affine invariant submanifold covers a translation surface in a lower genus hyperelliptic component of a stratum of abelian differentials. This result implies finiteness of algebraically primitive Teichmuller curves in all hyperelliptic components for genus greater than two. A classification of all GL(2, R) orbit closures in hyperelliptic components of strata (up to computing connected components and up to finitely many nonarithmetic rank one orbit closures) is provided. Our main theorem resolves a pair of conjectures of Mirzakhani in the case of hyperelliptic components of moduli space.
Optical pulsations from the anomalous X-ray pulsar 1E 1048.1–5937

We present high-speed optical photometry of the anomalous X-ray pulsar 1E 1048.1-5937 obtained with ULTRACAM on the 8.2-m Very Large Telescope in 2007 June. We detect 1E 1048.1-5937 at a magnitude of i' = 25.3 +/- 0.2, consistent with the values found by Wang et al. and hence confirming their conclusion that the source was approximately 1 mag brighter than in 2003-06 due to an on-going X-ray flare that started in 2007 March. The increased source brightness enabled us to detect optical pulsations with an identical period (6.458 s) to the X-ray pulsations. The root-mean-square (rms) pulsed fraction in our data is 21 +/- 7 per cent, approximately the same as the 2-10 keV X-ray rms pulsed fraction. The optical and X-ray pulse profiles show similar morphologies and appear to be approximately in phase with each other, the latter lagging the former by only 0.06 +/- 0.02 cycles. The optical pulsations in 1E 1048.1-5937 are very similar in nature to those observed in 4U 0142+61. The implications of our observations for models of anomalous X-ray pulsars are discussed.
On the boundedness of multilinear fractional strong maximal operators with multiple weights

In this paper, we investigated the boundedness of multilinear fractional strong maximal operator $\mathcal{M}_{\mathcal{R},\alpha}$ associated with rectangles or related to more general basis with multiple weights $A_{(\vec{p},q),\mathcal{R}}$. In the rectangles setting, we first gave an end-point estimate of $\mathcal{M}_{\mathcal{R},\alpha}$, which not only extended the famous linear result of Jessen, Marcinkiewicz and Zygmund, but also extended the multilinear result of Grafakos, Liu, P\'{e}rez and Torres ($\alpha=0$) to the case $0<\alpha<mn. $ Then, in one weight case, we gave several equivalent characterizations between $\mathcal{M}_{\mathcal{R},\alpha}$ and $A_{(\vec{p},q),\mathcal{R}}$, by applying a different approach from what we have used before. Moreover, a sufficient condition for the two weighted norm inequality of $\mathcal{M}_{\mathcal{R},\alpha}$ was presented and a version of vector-valued two weighted inequality for the strong maximal operator was established when $m=1$. In the general basis setting, we further studied the properties of the multiple weights $A_{(\vec{p},q),\mathcal{R}}$ conditions, including the equivalent characterizations and monotonic properties, which essentially extended one's previous understanding. Finally, a survey on multiple strong Muckenhoupt weights was given, which demonstrates the properties of multiple weights related to rectangles systematically.
Global variational solutions to a class of fractional SPDE’s on unbounded domains

Abstract In this article, we prove new results regarding the existence and the uniqueness of global variational solutions to Neumann initial-boundary value problems for a class of non-autonomous stochastic parabolic partial differential equations. The equations we consider are defined on unbounded open domains in Euclidean space satisfying certain geometric conditions and are driven by a multiplicative noise derived from an infinite-dimensional fractional Wiener process characterized by a sequence of Hurst parameters H=. These parameters are in fact subject to further constraints that are intimately tied up with the nature of the nonlinearity in the stochastic term of the equations, and with the choice of the functional spaces in which the problem at hand is well-posed. Our method of proof rests on compactness arguments in an essential way.
Quintic algebras over Dedekind domains and their resolvents

In this paper, the parametrization of rings of ranks 2, 3, and 4 over Dedekind domains, found in the author's paper "Rings of small rank over a Dedekind domain and their ideals," is extended to rank 5, following Bhargava's parametrization of quintic Z-algebras.
NEW SIGNATURES OF THE MILKY WAY FORMATION IN THE LOCAL HALO AND INNER-HALO STREAMERS IN THE ERA OF GAIA

We explore the vicinity of the Milky Way through the use of spectrophotometric data from the Sloan Digital Sky Survey and high-quality proper motions derived from multi-epoch positions extracted from the Guide Star Catalog II database. In order to identify and characterize streams as relics of the Milky Way formation, we start with classifying, selecting, and studying 2417 subdwarfs with [ Fe / H ] < − 1.5 ? > up to 3 kpc away from the Sun as tracers of the local halo system. Then, through phase-space analysis, we find statistical evidence of five discrete kinematic overdensities among 67 of the fastest-moving stars and compare them to high-resolution N-body simulations of the interaction between a Milky Way–like galaxy and orbiting dwarf galaxies with four representative cases of merging histories. The observed overdensities can be interpreted as fossil substructures consisting of streamers torn from their progenitors; such progenitors appear to be satellites on prograde and retrograde orbits on different inclinations. In particular, of the five detected overdensities, two appear to be associated, yielding 21 additional main-sequence members, with the stream of Helmi et al. that our analysis confirms is on a high-inclination prograde orbit. The three newly identified kinematic groups could be associated with the retrograde streams detected by Dinescu and Kepley et al.; whatever their origin, the progenitor(s) would be on retrograde orbit(s) and inclination(s) within the range 10 ° ÷ 60 ° ? > . Finally, we use our simulations to investigate the impact of observational errors and compare the current picture to the promising prospect of highly improved data expected from the Gaia mission.
Recognising risk, influencing reality and mental healthcare in a regional emergency department

Mental health presentations to EDs continue to rise with associated challenges increasingly understood and well documented. Despite growing evidence of current and ongoing systemic issues contributing to this increase, there continues to be a lack of administrative engagement to address ED attendance, with avoidance and diversion strategies initiated during the COVID‐19 pandemic no longer prioritised, despite growing need. Clear and well‐documented reports of ED overcrowding and bed boarding is evidence that things need to change. Moreover, if innovative action is not taken, the risk and reality is that long waits, poor outcomes and exposure to unsafe conditions will continue. This is broadly unacceptable to consumers, their carers and the broader ED network. Delayed action in seeking alternative solutions only reinforces the risk and reality that people experiencing mental health concerns have ‘Nowhere Else To Go’.
Albumin to prealbumin ratio in peritoneal dialysis patients: Clinical implication and outcome prediction

Background Serum prealbumin level is slightly higher, whereas albumin is lower in peritoneal dialysis (PD) than hemodialysis (HD) patients. It is unknown whether albumin to prealbumin ratio (APR) is associated with mortality risk among PD patients. This study aimed to evaluate the clinical implications of APR and its prediction value on long-term outcomes of PD patients. Methods The study population were prevalent PD patients at a tertiary hospital. Based on APR, a total of 220 PD patients were divided into 3 groups: group 1: top tertile, median APR: 121.1; IQR:109.5–131.9 (n = 73, male: 37%; age: 59±13); group 2: middle tertile, median APR: 97.1; IQR 93.5–100.0 (n = 73, male:37%; age: 54±14), and group3: bottom tertile, median APR: 81.3; IQR:76.8–85.0 (n = 74, male:38%; 54±11). Patients were followed up for a maximum of 5 years. Outcome of interest was all-cause mortality. Results Group 1 was characterized by older age, higher prevalence of diabetes, lower nPCR, higher Davies score and hs-CRP level. APR positively correlated to hs-CRP (β = 0.149, p = 0.045), but negatively correlated to nPCR (β = -0.161, p = 0.034). Hyperprealbuminemia, accounting for 0%, 23.3%, and 82.4% in groups 1,2, and 3, was associated with a lower risk for mortality (HR:0.41, 95%CI = 0.23–0.73). The cumulative survival is significantly lower in group 1 than the other two groups. By multivariable Cox regression, APR (HR:1.02; 95%CI:1.01–1.03) was found to be an independent predictor of long-term mortality. Conclusion PD patients with high APR are characterized by having more comorbidities and marked malnutrition-inflammation status, and are associated with long-term mortality, whereas hyperprealbuminemia and lower APR are favorable prognostic factors.
Influence of social jetlag on daytime sleepiness in obstructive sleep apnea

Social jetlag is the discrepancy between socially determined sleep timing on workdays and biologically determined sleep timing on days free of social obligation. Poor circadian timing of sleep may worsen sleep quality and increase daytime sleepiness in obstructive sleep apnea (OSA). We analysed de‐identified data from 2,061 participants (75.2% male, mean [SD] age 48.6 [13.4] years) who completed Sleep Apnea Global Interdisciplinary Consortium (SAGIC) research questionnaires and underwent polysomnography at 11 international sleep clinic sites. Social jetlag was calculated as the absolute difference in the midpoints of sleep between weekdays and weekends. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS). Linear regression analyses were performed to estimate the association between social jetlag and daytime sleepiness, with consideration of age, sex, body mass index, ethnicity, insomnia, alcohol consumption, and habitual sleep duration as confounders. Of the participants, 61.5% had <1 h of social jetlag, 27.5% had 1 to <2 h, and 11.1% had ≥2 h. Compared to those with <1 h of social jetlag, those with ≥2 h of social jetlag had 2.07 points higher ESS (95% confidence interval [CI] 0.77–3.38, p = 0.002), and those with 1 to <2 h of social jetlag had 0.80 points higher ESS (95% CI 0.04–1.55, p = 0.04) after adjustment for potential confounding. Interaction with OSA severity was observed; social jetlag appeared to have the greatest effect on daytime sleepiness in mild OSA. As social jetlag exacerbates daytime sleepiness in OSA, improving sleep timing may be a simple but novel therapeutic target for reducing the impact of OSA.
ANALYSIS OF SPIN–ORBIT MISALIGNMENT IN THE ECLIPSING BINARY DI HERCULIS

The eclipsing binary DI Herculis (DI Her) is known to exhibit anomalously slow apsidal precession below the rate predicted by general relativity. Recent measurements of the Rossiter–McLaughlin effect indicate that stellar spins in DI Her are almost orthogonal to the orbital angular momentum, which explains the anomalous precession in agreement with the earlier theoretical suggestion by Shakura. However, these measurements yield only projections of the spin–orbit angles onto the sky plane, leaving the spin projection onto our line of sight unconstrained. Here we describe a method for determining the full three-dimensional spin orientation of the binary components relying on the use of the gravity-darkening effect, which is significant for the rapidly rotating stars in DI Her. Gravity darkening gives rise to a nonuniform brightness distribution over the stellar surface, the pattern of which depends on the stellar spin orientation. Using archival photometric data obtained during multiple eclipses over several decades, we are able to constrain the unknown spin angles in DI Her with this method, finding that the spin axes of both stars lie close to the plane of the sky. Our procedure fully accounts for the precession of stellar spins over the long time span of observations.