Universal Multistream Radial Structures of Cold Dark Matter Halos

Virialized halos of cold dark matter generically exhibit multistream structures of accreted dark matter within an outermost radial caustic known as the splashback radius. By tracking the particle trajectories that accrete onto the halos in cosmological N-body simulations, we count their number of apocenter passages (p) and use them to characterize the multistream structure of dark matter particles. We find that the radial density profile for each stream, classified by the number of apocenter passages, exhibits universal features and can be described by a double power-law function comprising shallow inner slopes and steep outer slopes of indices of −1 and −8, respectively. Surprisingly, these properties hold over a wide range of halo masses. The double power-law feature is persistent when dividing the sample by concentration or accretion rate. The dependence of the characteristic scale and amplitude of the profile on p cannot be replicated by known self-similar solutions, requiring consideration of complexities such as the distribution of angular momentum or mergers

Multi-stream radial structure of cold dark matter haloes from particle trajectories: deep inside splashback radius

By tracking trajectories of dark matter (DM) particles accreting onto haloes in cosmological $N$-body simulations, we investigate the radial phase-space distribution of cold dark matter (CDM) haloes, paying attention to their inner regions deep inside the halo boundary called the splashback radius, where the particles undergo multi-stream flows. Improving the analysis by Sugiura et al., we classify DM particles by the number of apocenter passages, $p$, and count it up to $p=40$ for each halo over a wide mass range. Quantifying the radial density profile for particles having the same value of $p$, we find that it generally exhibits a double-power law feature, whose indices of inner and outer slopes are well-described by $-1$ and $-8$, respectively. Its characteristic scale and density are given as a simple fitting function of $p$, with a weak halo mass dependence. Interestingly, summing up these double-power law profiles beyond $p=40$ reproduces well the total density profile of simulated haloes. The double-power law nature is persistent and generic not only in mass-selected haloes but also in haloes selected in different criteria. Our results are compared with self-similar solutions that describe the stationary and spherical accretion of DM. We find that even when introducing a non-zero angular momentum, none of them explain the radial multi-stream structure. The analysis with particle trajectories tracing back to higher redshifts suggests that the double-power law nature has been established during an early accretion phase and remains stable.Comment: 24 pages, 20 figures. Version consistent with that accepted by MNRA

Multistream radial structure of cold dark matter haloes from particle trajectories: deep inside splashback radius

By tracking trajectories of dark matter (DM) particles accreting on to haloes in cosmological N-body simulations, we investigate the radial phase-space distribution of cold dark matter (CDM) haloes, paying attention to their inner regions deep inside the halo boundary called the splashback radius, where the particles undergo multistream flows. Improving the analysis by Sugiura et al., we classify DM particles by the number of apocentre passages, p, and count it up to p = 40 for each halo over a wide mass range. Quantifying the radial density profile for particles having the same value of p, we find that it generally exhibits a double power-law feature, whose indices of inner and outer slopes are well described by −1 and −8, respectively. Its characteristic scale and density are given as a simple fitting function of p, with a weak halo mass dependence. Interestingly, summing up these double power-law profiles beyond p = 40 reproduces well the total density profile of simulated haloes. The double power-law nature is persistent and generic not only in mass-selected haloes but also in haloes selected in different criteria. Our results are compared with self-similar solutions that describe the stationary and spherical accretion of DM. We find that even when introducing a non-zero angular momentum, none of them explain the radial multistream structure. The analysis with particle trajectories tracing back to higher redshifts suggests that the double power-law nature has been established during an early accretion phase and remains stable

Stress, Microglial Activation, and Mental Disorders

Microglia play a major role in immune response in the brain. Recent progress in studies for microglia suggests that stress causes morphological alterations in microglia and affects microglial humoral release and phagocytosis. In this review, we present a molecular mechanism by which stress impacts microglia. Then, we describe current findings for the involvement of microglia in stress-related mental disorders including posttraumatic stress disorder (PTSD), depression, and pain enhancement. We focus on preclinical and clinical studies. Preclinical PTSD studies using animal models with fear memory dysregulation show neuroinflammation by microglia and altered microglial phagocytosis, two imaging studies and a postmortem study assessing neuroinflammation in PTSD patients show contradictory results. Imaging studies suggest neuroinflammation in depressed patients, postmortem studies show no microglial inflammatory changes in non-suicidal depressed patients. Although it has been established that microglia in the spinal cord play a pivotal role in chronic neuropathic pain, several preclinical studies suggest microglia also participate in stress-induced pain. A clinical study with induced microglia-like (iMG) cells and an imaging study indicate neuroinflammation by microglia in fibromyalgia patients. We believe that progress in interactive research between humans and animals elucidates the role of microglia in the pathophysiology of stress-related mental disorders

Programmable time-multiplexed squeezed light source

One of the leading approaches to large-scale quantum information processing (QIP) is the continuous-variable (CV) scheme based on time multiplexing (TM). As a fundamental building block for this approach, quantum light sources to sequentially produce time-multiplexed squeezed-light pulses are required; however, conventional CV TM experiments have used fixed light sources that can only output the squeezed pulses with the same squeezing levels and phases. We here demonstrate a programmable time-multiplexed squeezed light source that can generate sequential squeezed pulses with various squeezing levels and phases at a time interval below 100 ns. The generation pattern can be arbitrarily chosen by software without changing its hardware configuration. This is enabled by using a waveguide optical parametric amplifier and modulating its continuous pump light. Our light source will implement various large-scale CV QIP tasks.Comment: 14 pages, 7 figure

Sleep Deprivation Influences Diurnal Variation of Human Time Perception with Prefrontal Activity Change: A Functional Near-Infrared Spectroscopy Study

Human short-time perception shows diurnal variation. In general, short-time perception fluctuates in parallel with circadian clock parameters, while diurnal variation seems to be modulated by sleep deprivation per se. Functional imaging studies have reported that short-time perception recruits a neural network that includes subcortical structures, as well as cortical areas involving the prefrontal cortex (PFC). It has also been reported that the PFC is vulnerable to sleep deprivation, which has an influence on various cognitive functions. The present study is aimed at elucidating the influence of PFC vulnerability to sleep deprivation on short-time perception, using the optical imaging technique of functional near-infrared spectroscopy. Eighteen participants performed 10-s time production tasks before (at 21:00) and after (at 09:00) experimental nights both in sleep-controlled and sleep-deprived conditions in a 4-day laboratory-based crossover study. Compared to the sleep-controlled condition, one-night sleep deprivation induced a significant reduction in the produced time simultaneous with an increased hemodynamic response in the left PFC at 09:00. These results suggest that activation of the left PFC, which possibly reflects functional compensation under a sleep-deprived condition, is associated with alteration of short-time perception

Swallowing-like activity elicited in neonatal rat medullary slice preparation

Kondo T., Yamanishi T., Nishio T., et al. Swallowing-like activity elicited in neonatal rat medullary slice preparation. Brain Research 1837, 148955 (2024); https://doi.org/10.1016/j.brainres.2024.148955.Swallowing is induced by a central pattern generator in the nucleus tractus solitarius (NTS). We aimed to create a medullary slice preparation to elucidate the neural architecture of the central pattern generator of swallowing (Sw-CPG) and record its neural activities. Experiments were conducted on 2-day-old Sprague–Dawley rats (n = 46). The brainstem-spinal cord was transected at the pontomedullary and cervicothoracic junctions; the medulla was sliced transversely at thicknesses of 600, 700, or 800 μm. The rostral end of the slice was 100 μm rostral to the vagus nerve. We recorded hypoglossal nerve activity and electrically stimulated the vagus nerve or microinjected bicuculline methiodide (BIC) into the NTS. The 800-μm slices generated both rhythmic respiratory activity and electrically elicited neural activity. The 700-μm slices generated only respiratory activity, while the 600-μm slices did not generate any neural activity. BIC microinjection into the NTS in 800-μm slices resulted in the typical activity that closely resembled the swallowing activity reported in other experiments. This swallowing-like activity consistently lengthened the respiratory interval. Despite complete inhibition of respiratory activity, weak swallowing-like activity was observed under bath application of a non-NMDA receptor antagonist. Contrastingly, bath application of NMDA receptor antagonists resulted in a complete loss of swallowing-like activity and no change in respiratory activity. These results suggest that the 800-μm medullary slice preparation contains both afferent and efferent neural circuits and pattern generators of swallowing activity. Additionally, NMDA receptors may be necessary for generating swallowing activity. This medullary slice preparation can therefore elucidate Sw-CPG neural networks

Verifying the validity and reliability of the Japanese version of the Face, Legs, Activity, Cry, Consolability (FLACC) Behavioral Scale

BackgroundPediatric patients, especially in the preverbal stage, cannot self-report intensity of pain therefore several validated observational tools, including the Face, Legs, Activity, Cry, Consolability (FLACC) Behavioral Scale, have been used as a benchmark to evaluate pediatric pain. Unfortunately, this scale is currently unavailable in Japanese, precluding its widespread use in Japanese hospitals.ObjectivesTo translate and verify the validity and reliability of the Japanese version of the FLACC Behavioral Scale.MethodBack-translation was first conducted by eight medical researchers, then an available sample of patients at the University of Tsukuba Pediatric Intensive Care Unit (from May 2017 to August 2017) was enrolled in a clinical study. Two researchers evaluated the validity of the translated FLACC Behavioral Scale by weighted kappa coefficient and intraclass correlation coefficients (ICC). Observational pain was simultaneously measured by the visual analog scale (VAS obs) and reliability was evaluated by correlation analysis.ResultThe original author approved the translation. For the clinical study, a total of 121 observations were obtained from 24 pediatric patients. Agreement between observers was highly correlated for each of the FLACC categories (Face: κ = 0.85, Leg: κ = 0.74, Activity: κ = 0.89, Cry: κ = 0.93, Consolability: κ = 0.93) as well as the total score (Total: κ = 0.95,). Correlation analysis demonstrated a good criterion validation between the FLACC scale and the VAS obs. (r = 0.96)ConclusionOur Japanese version of the FLACC Behavioral Scale shows high validity and reliability

A Case of Skull Base Osteomyelitis with Multiple Cerebral Infarction

Skull base osteomyelitis is classically documented as an extension of malignant otitis externa. Initial presentation commonly includes aural symptoms and cranial nerve dysfunctions. Here we present a case that emerged with multiple infarctions in the right cerebrum. A male in his 70s with diabetes mellitus and chronic renal failure presented with left hemiparesis. Imaging studies showed that blood flow in the carotid artery remained at the day of onset but was totally occluded 7 days later. However, collateral blood supply prevented severe infarction. These findings suggest that artery-to-artery embolization from the petrous and/or cavernous portion of the carotid artery caused the multiple infarctions observed on initial presentation. Osteomyelitis of the central skull base was diagnosed on the basis of the following findings taken together: laboratory results showing high levels of inflammation, presence of Pseudomonas aeruginosa in the otorrhea and blood culture, multiple cranial nerve palsies that appeared later, the bony erosion observed on CT, and the mass lesion on MRI. Osteomyelitis was treated successfully by long-term antibiotic therapy; however, the patient experienced cefepime-induced neurotoxicity during therapy. The potential involvement of the internal carotid artery in this rare and life-threatening disease is of particular interest in this case