The origin of ultra diffuse galaxies: stellar feedback and quenching

We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies. We show that stellar feedback-generated outflows that dynamically heat galactic stars, together with a passively aging stellar population after imposed quenching (from e.g. infall into a galaxy cluster), naturally reproduce the observed population of red UDGs, without the need for high spin halos or dynamical influence from their host cluster. We reproduce the range of surface brightness, radius and absolute magnitude of the observed z=0 red UDGs by quenching simulated galaxies at a range of different times. They represent a mostly uniform population of dark matter-dominated galaxies with M_star ~1e8 Msun, low metallicity and a broad range of ages. The most massive simulated UDGs require earliest quenching and are therefore the oldest. Our simulations provide a good match to the central enclosed masses and the velocity dispersions of the observed UDGs (20-50 km/s). The enclosed masses of the simulated UDGs remain largely fixed across a broad range of quenching times because the central regions of their dark matter halos complete their growth early. A typical UDG forms in a dwarf halo mass range of Mh~4e10-1e11 Msun. The most massive red UDG in our sample requires quenching at z~3 when its halo reached Mh ~ 1e11 Msun. If it, instead, continues growing in the field, by z=0 its halo mass reaches > 5e11 Msun, comparable to the halo of an L* galaxy. If our simulated dwarfs are not quenched, they evolve into bluer low-surface brightness galaxies with mass-to-light ratios similar to observed field dwarfs. While our simulation sample covers a limited range of formation histories and halo masses, we predict that UDG is a common, and perhaps even dominant, galaxy type around Ms~1e8 Msun, both in the field and in clusters.Comment: 20 pages, 13 figures; match the MNRAS accepted versio

Optical Flow on Evolving Surfaces with an Application to the Analysis of 4D Microscopy Data

We extend the concept of optical flow to a dynamic non-Euclidean setting. Optical flow is traditionally computed from a sequence of flat images. It is the purpose of this paper to introduce variational motion estimation for images that are defined on an evolving surface. Volumetric microscopy images depicting a live zebrafish embryo serve as both biological motivation and test data.Comment: The final publication is available at link.springer.co

Aerothermodynamic Testing and Boundary Layer Trip Sizing of the HIFiRE Flight 1 Vehicle

An experimental wind tunnel test was conducted in the NASA Langley Research Center s 20-Inch Mach 6 Air Tunnel in support of the Hypersonic International Flight Research Experimentation Program. The information in this article is focused on the Flight 1 configuration, the first in a series of flight experiments. The article documents experimental measurements made over a Reynolds numbers range of 2.1x10(exp 6)/ft to 5.6x10(exp 6)/ft and angles of attack of -5 to +5 deg on several scaled ceramic heat transfer models of the Flight 1 configuration. Global heat transfer was measured using phosphor thermography and the resulting images and heat transfer distributions were used to infer the state of the boundary layer on the vehicle windside and leeside surfaces. Boundary layer trips were used to force the boundary layer turbulent and the experimental data highlighted in this article were used to size and place the boundary layer trip for the flight vehicle. The required height of the flight boundary layer trip was determined to be 0.079 in and the trip was moved from the design location of 7.87 in to 20.47 in to ensure that augmented heating would not impact the laminar side of the vehicle. Allowable roughness was selected to be 3.2x10(exp -3) in

Effect of Tai Chi on Vascular Function Among Patients with Peripheral Neuropathy

Foot pain due to Peripheral Neuropathy (PN) is one of the factors affecting walking ability. It has been reported that diminished vascular function contributes to a decrease in physical function in individuals with PN. Microvascular disturbances have been reported in humans with neuropathic pain. Tai Chi, a Chinese conditioning exercise, has been associated with enhanced endothelial function. However, the effect of Tai Chi training on microvascular function in patients with PN has not been studied. This study aimed to assess the effects of Tai Chi on vascular function (i.e., vascular reactivity) and functional exercise capacity among patients with PN. Thirty-seven participants (men = 21, women = 16) were randomly assigned to either Tai Chi exercise (Ex, n = 20, age: 71 ± 9.50 years) or control group (Con, n = 17, age: 75 ± 9.02 years). Exercise training consisted of 12-week progressive Tai Chi (i.e., Yang Style), offered 3 times per week, 60 minutes sessions. The Con group did not participate in any exercise activity. Before and after training, vascular function [finger tip digital thermal monitoring of vascular reactivity] and functional exercise capacity [Six-Minute Walk test (6MW)] were evaluated. The Ex group experienced a significant 25% increase in vascular reactivity index from baseline [1.93 ± 0.43 to 2.41 ± 0.47, (P \u3c 0.05)]. In addition, the 6MW test increased significantly in the Ex group by 28% [pre = 392 ± 93; post = 503 ± 105 m, (P \u3c 0.05)]. In the control group no significant changes were observed in either vascular function [1.83 ± 0.43 to 1.81 ± 0.37] or in the 6MW test [393 ± 142 to 398 ± 149 m]. Participants experienced no complications and/or falls as a result of the intervention. These findings demonstrated that in patients with PN, a 12-week progressive Tai Chi exercise program was capable of increasing not only vascular function, specifically vascular reactivity index, but also of increasing the distance covered during the 6MW test. Clearly, this study underlies the importance of Tai Chi as an effective and safe exercise intervention suitable for patients with PN

Isoflurane cracks the polycarbonate connector of extra-corporeal circuit -A case report-

Cardiopulmonary bypass (CPB) is widely used for cardiac surgery by virtue of its proven safety over the course of its use during the past half century. Even though perfusion is safer, incidents still occur. During the repair of a ventricular-septal defect in an 11-month-old infant, we experienced a critical incident related to the potential hazardous effect of volatile anesthetics on the polycarbonate connector of extra-corporeal circuit. The damage to the polycarbonate connector had occurred after spillage of isoflurane during the filling of the vaporizer, causing it to crack and leak. The incident was managed by replacement of the cracked connector during a temporary circulatory arrest. The patient was hypothermic and the time off bypass was less than 1.5 min. There were no neurologic sequelae, the patient made an uneventful recovery. In conclusion, the spillage of volatile anesthetics can cause cracks in the polycarbonate connector of the extra-corporeal circuit, leading to potentially interruption of CPB

Tai Chi Exercise on Muscle Strength and Physical Function in Peripheral Neuropathy Patients

This poster was presented at the American College of Sports Medicine\u27s (ACSM) 63rd Annual Meeting and World Congresses, Boston, MA.https://scholarworks.uttyler.edu/fac_posters/1016/thumbnail.jp

Level Set Segmentation with Shape and Appearance Models Using Affine Moment Descriptors

We propose a level set based variational approach that incorporates shape priors into edge-based and region-based models. The evolution of the active contour depends on local and global information. It has been implemented using an efficient narrow band technique. For each boundary pixel we calculate its dynamic according to its gray level, the neighborhood and geometric properties established by training shapes. We also propose a criterion for shape aligning based on affine transformation using an image normalization procedure. Finally, we illustrate the benefits of the our approach on the liver segmentation from CT images

Perilipin A is essential for the translocation of hormone-sensitive lipase during lipolytic activation

Akey step in lipolytic activation of adipocytes is the translocation of hormone-sensitive lipase (HSL) from the cytosol to the surface of the lipid storage droplet. Adipocytes from perilipin-null animals have an elevated basal rate of lipolysis compared with adipocytes from wild-type mice, but fail to respond maximally to lipolytic stimuli. This defect is downstream of the β-adrenergic receptor–adenylyl cyclase complex. Now, we show that HSL is basally associated with lipid droplet surfaces at a low level in perilipin nulls, but that stimulated translocation from the cytosol to lipid droplets is absent in adipocytes derived from embryonic fibroblasts of perilipin-null mice. We have also reconstructed the HSL translocation reaction in the nonadipocyte Chinese hamster ovary cell line by introduction of GFP-tagged HSL with and without perilipin A. On activation of protein kinase A, HSL-GFP translocates to lipid droplets only in cells that express fully phosphorylatable perilipin A, confirming that perilipin is required to elicit the HSL translocation reaction. Moreover, in Chinese hamster ovary cells that express both HSL and perilipin A, these two proteins cooperate to produce a more rapidly accelerated lipolysis than do cells that express either of these proteins alone, indicating that lipolysis is a concerted reaction mediated by both protein kinase A–phosphorylated HSL and perilipin A

Doing gender locally: The importance of ‘place’ in understanding marginalised masculinities and young men’s transitions to ‘safe’ and successful futures

Observable anxieties have been developing about the position of boys and young men in contemporary society in recent years. This is expressed as a crisis of masculinity, in which place is often implicitly implicated, but is rarely considered for its role in the shaping of young men’s practices, trajectories and aspirations. Drawing on research conducted with young people who accessed a range of social care support services, this article argues that transition means different things for young men in different locales and that local definitions of masculinity are required to better understand young men’s lives and the opportunities available to them. The authors argue that home life, street life, individual neighbourhoods, regions and nations all shaped the young men’s identities and the practices they (and the staff working with them) drew on in order to create successful futures and ‘safe’ forms of masculinity. It is suggested that this place-based approach has the potential to re-shape the ‘crisis’ discourse surrounding masculinity and the anxieties associated with young men