Numerical modelling of liquid droplet dynamics in microgravity

Microgravity provides ideal experimental conditions for studying highly reactive and under-cooled materials where there is no contact between the sample and the other experimental apparatus. The non-contact conditions allow material properties to be measured from the oscillating liquid droplet response to perturbations. This work investigates the impact of a strong magnetic field on these measurement processes for weakly viscous, electrically conducting droplets. We present numerical results using an axisymmetric model that employs the pseudo-spectral collocation method and a recently developed 3D model. Both numerical models have been developed to solve the equations describing the coupled electromagnetic and fluid flow processes. The models represent the changing surface shape that results from the interaction between forces inside the droplet and the surface tension imposed boundary conditions. The models are used to examine the liquid droplet dynamics in a strong DC magnetic field. In each case the surface shape is decomposed into a superposition of spherical harmonic modes. The oscillation of the individual mode coefficients is then analysed to determine the oscillation frequencies and damping rates that are then compared to the low amplitude solutions predicted by the published analytical asymptotic theory

Impact of cloud-borne aerosol representation on aerosol direct and indirect effects

International audienceAerosol particles attached to cloud droplets are much more likely to be removed from the atmosphere and are much less efficient at scattering sunlight than if unattached. Models used to estimate direct and indirect effects of aerosols employ a variety of representations of such cloud-borne particles. Here we use a global aerosol model with a relatively complete treatment of cloud-borne particles to estimate the sensitivity of simulated aerosol, cloud and radiation fields to various approximations to the representation of cloud-borne particles. We find that neglecting transport of cloud-borne particles introduces little error, but that diagnosing cloud-borne particles produces global mean biases of 20% and local errors of up to 40% for aerosol, droplet number, and direct and indirect radiative forcing. Aerosol number, aerosol optical depth and droplet number are significantly underestimated in regions and seasons where and when wet removal is primarily by stratiform rather than convective clouds (polar regions during winter), but direct and indirect effects are less biased because of the limited sunlight there and then. A treatment that predicts the total mass concentration of cloud-borne particles for each mode yields smaller errors and runs 20% faster than the complete treatment. The errors are much smaller than current estimates of uncertainty in direct and indirect effects of aerosols, which suggests that the treatment of cloud-borne aerosol is not a significant source of uncertainty in estimates of direct and indirect effects

The impact of childbirth-related post-traumatic stress on a couple's relationship: a systematic review and meta-synthesis

Objective: This review aimed to identify the impact of childbirth-related post-traumatic stress disorder (PTSD) or symptoms (PTSS) on a couple’s relationship. Background: Childbirth can be psychologically traumatic, and can lead to PTSD. There is emerging evidence that experiencing a traumatic birth can affect the quality of the couple’s relationship. This is an important issue as poor quality relationships can impact on the well-being of partners, their parenting, and the welfare of the infant. Methods: A systematic search was conducted of Amed, CENTRAL, Cinahl, Embase, Maternity and Infant Care, Medline, MITCognet, POPLINE, PsycARTICLES, PsycBITE, PsycINFO, Pubmed, and Science Direct. Additionally, grey literature, citation, and reference searches were conducted. Papers were eligible for inclusion if they reported qualitative data about parents who had experienced childbirth and measures of PTSD or PTSS and the relationship were taken. Analysis was conducted using meta-ethnography. Results: Seven studies were included in the meta-synthesis. Results showed that childbirth-related PTSD or PTSS can have a perceived impact on the couple’s relationship and five themes were identified: negative emotions; lack of understanding and support; loss of intimacy; strain on the relationship; and strengthened relationships. A model of proposed interaction between these themes is presented. Conclusions: The impact of childbirth-related PTSD or PTSS on the couple’s relationships is complex. As the quality of the couple relationship is important to family wellbeing, it is important that health care professionals are aware of the impact of experiencing psychologically traumatic childbirth as impetus for prevention and support

Retinal synaptic arrays: Continuing development in the adult goldfish

We report a light- and electron-microscopic examination of the inner plexiform layer of the central retina of young (c. 1 year) and old (3–4 year) goldfish. There were no new neurons added to this region during the growth period. Nonetheless, there were substantially more synapses (per cell, per mm 2 , or per degree 2 ) in the older retinas. This result is discussed in the contexts of retinal function and neural development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50006/1/901850210_ftp.pd

Liquid Droplet Dynamics in Gravity Compensating High Magnetic Field

Numerical models are used to investigate behavior of liquid droplets suspended in high DC magnetic fields of various configurations providing microgravity-like conditions. Using a DC field it is possible to create conditions with laminar viscosity and heat transfer to measure viscosity, surface tension, electrical and thermal conductivities, and heat capacity of a liquid sample. The oscillations in a high DC magnetic field are quite different for an electrically conducting droplet, like liquid silicon or metal. The droplet behavior in a high magnetic field is the subject of investigation in this paper. At the high values of magnetic field some oscillation modes are damped quickly, while others are modified with a considerable shift of the oscillating droplet frequencies and the damping constants from the non-magnetic case

Expansion of the half retinal projection to the tectum in goldfish: An electrophysiological and Anatomical study

The topographical retino-tectal projection of goldfish was electrophysiologically mapped at various intervals after surgical removal of the nasal half of the retina and pigment epithelium. The remaining projection was initially restricted to the appropriate rostral half of the tectum, even if the nerve was crushed and allowed to regenerate. But later, after 137 days or more, it showed a progressive expansion onto the foreign caudal half of the tectum. The magnification factor, the number of micrometers of tectum per degree in the visual field, doubled in the rostro-caudal but not in the medio-lateral direction. Analysis of the sequence of the expansion showed that a few fibers originally projecting nearest the denervated area were the first to spread over it. Then, progressively more fibers moved caudally until a nearly uniform representation of the half retina was established on the tectum. Radioautography also demonstrated that retinal fiber terminals had invaded the caudal tectum. The retinae of these fish were also examined histologically. The density of ganglion cells had not increased, but they consistently showed the axonal reaction. This was not found to be associated with any initial surgical trauma, but rather with the movement of their fiber terminals within the tectum. Frozen sections, through half retinal and normal eyes, were cut and photographed for comparison of ocular geometry. Operated eyes were normal except for a slight but consistent loss of ocular volume. Analysis of the optical geometry showed that recording with fish in air produced two effects: Myopia (10° blur circle, or less) and enlargement of the visual field by 15% to 20%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50003/1/901770206_ftp.pd

STUDI EKOLOGI OSEANOGRAFI TELUK MANADO UNTUK PENENTUAN STRUKTUR ARTIFICIAL CORAL GARDEN DAN AREA MANGROVE SEBAGAI DESTINASI WISATA BARU

The purpose of this study is to investigate the ecological conditions of mangrove ecosystems in the Manado Bay and analyze the suitability of the mangrove ecosystems as a new tourist destination, examine the oceanographic conditions in the Manado Bay area, study the data on the development of coral reef ecosystems to be able to produce artificial coral reefs and produce mangrove areas and coral reefs artificial as a new tourist destination. This research was conducted in April - September 2019 with the location of Manado Bay and the location of the Manado Bay coral reef ecosystem survey set at 3 sample points, equipped with 3 points in front of the BOBOCA Malalayang monument, in front of the Malalayang gas station and ANTRA Sario. Retrieval of coral reef data is by using the Line Intercept Transect (LIT) method. LIT observations were carried out with SCUBA diving at a depth of 6m. Observations were made by recording coral lifeforms found along the transect line, and calculating the percentage of the selection. The data taken is the percentage of dead coral cover, live coral, and type of life form, diversity index taken at 3 sample points. From field observations found on Site 2 (Front of Malalayang gas station) the condition of coral reefs is included in the good category, with the percentage of live coral cover (Hard Coral) of 55%. At this station found various types of coral growth, but the highest at this station is a form of growth of Coral Masive (CM) of 19.2%, while the least found were corals in the form of Coral Mushrooms (Mushroom Coral) with a percentage of 0.4 %. Then Site 3, namely in ANTRA Sario obtained from coral reefs is included in the bad category, with the percentage of live coral cover (Hard Coral) only 7.1%. Coral Diversity in the three survey stations is different. Of the three stations determined above the Tugu Boboca Malalayang site with an index value of 2.54, followed at site 2 namely the Malalayang gas station with an index value of 2.36 and the lowest at site 3 at ANTRA Sario with an index value of 1.33. Furthermore, oceanographic conditions in the Gulf of Manado region are seen in the receding period, most of the air moves westward at the beginning of the period, then moves northeastward in the next period. While in the tide period the water moves northward, starting the period and then it is seen moving northeast and at the end of the period, the east direction.Key words : Coral reef, Oceanographic conditio

Birth of olfactory neurons: Lifelong neurogenesis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24850/1/0000277.pd

A comment on the "glissade"

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33915/1/0000180.pd

Automated retinotectology

The retinotectal projection has been the principal battleground, since the 1930s, for the experimental investigation of the factors determining specific neural connections. Since the late 1950s, the electrophysiological determination of the retinotectal map has been the dominant experimental method. Many of the conclusions derived with this method have been questioned (by other investigators using the same method), and some of these disputes remain unresolved even today. Recently, David Northmore and his associates have developed two automated methods for assessing retinotectal function which are described below. In different ways, these methods correct some of the deficiencies of the old method.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25889/1/0000452.pd