A Case of Problematic Diffusion

Sex determination techniques have diffused rapidly in India, and are being used to detect female fetuses and subsequently to abort them. This technology has spread rapidly because it imparts knowledge that is of great value within the Indian context, and because it fits in neatly with the modernization dynamic within India, which itself has enmeshed with traditional patriarchal institutions to oppress Indian women. More research needs to be done on ways to stem the adoption of problematic innovations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68396/2/10.1177_107554709401500301.pd

Search for gravitational-wave transients associated with magnetar bursts in advanced LIGO and advanced Virgo data from the third observing run

Gravitational waves are expected to be produced from neutron star oscillations associated with magnetar giant f lares and short bursts. We present the results of a search for short-duration (milliseconds to seconds) and longduration (∼100 s) transient gravitational waves from 13 magnetar short bursts observed during Advanced LIGO, Advanced Virgo, and KAGRA’s third observation run. These 13 bursts come from two magnetars, SGR1935 +2154 and SwiftJ1818.0−1607. We also include three other electromagnetic burst events detected by FermiGBM which were identified as likely coming from one or more magnetars, but they have no association with a known magnetar. No magnetar giant flares were detected during the analysis period. We find no evidence of gravitational waves associated with any of these 16 bursts. We place upper limits on the rms of the integrated incident gravitational-wave strain that reach 3.6 × 10−²³ Hz at 100 Hz for the short-duration search and 1.1 ×10−²² Hz at 450 Hz for the long-duration search. For a ringdown signal at 1590 Hz targeted by the short-duration search the limit is set to 2.3 × 10−²² Hz. Using the estimated distance to each magnetar, we derive upper limits upper limits on the emitted gravitational-wave energy of 1.5 × 1044 erg (1.0 × 1044 erg) for SGR 1935+2154 and 9.4 × 10^43 erg (1.3 × 1044 erg) for Swift J1818.0−1607, for the short-duration (long-duration) search. Assuming isotropic emission of electromagnetic radiation of the burst fluences, we constrain the ratio of gravitational-wave energy to electromagnetic energy for bursts from SGR 1935+2154 with the available fluence information. The lowest of these ratios is 4.5 × 103

Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages

A joint Fermi-GBM and Swift-BAT analysis of gravitational-wave candidates from the third gravitational-wave observing run

We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers

Constraints on the cosmic expansion history from GWTC–3

We use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding ${H}_{0}={68}_{-8}^{+12}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ (68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC–1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of ${H}_{0}={68}_{-6}^{+8}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ with the galaxy catalog method, an improvement of 42% with respect to our GWTC–1 result and 20% with respect to recent H0 studies using GWTC–2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814

Wavelet analysis of finite height grid turbulence over a flat plate

An experimental investigation was carried out in a wind tunnel in order to study the turbulent flow over a flat plate that is a scaledown of a photovoltaic (PV) panel. By inducing turbulence in the flow over a PV panel, its convective heat loss can be increased. The turbulence was generated by a plate with diamond-shaped perforations (grid), which was mounted vertically at the leading edge of the flat plate. Fourier and wavelet transforms are utilized to study the turbulence downstream of the grid at specific points. Results showed that at the height of the upper edge of the grid, turbulence has a higher kinetic energy than at the points behind the grid. For the points behind the grid, at all eddy size ranges, turbulence energy decayed significantly with downstream distance. For the points at grid height, it seems that for large eddies (frequency lower than 100 Hz) the energy increased in the downstream direction and for other ranges it decreased very slightly. This analysis may influence the design of passive flow devices meant to enhance the heat transfer from a PV panel\u27s surface

Turbulent flow over a flat plate downstream of a finite height perforated plate

An experimental investigation was carried out to study the turbulent flow over a flat plate in a wind tunnel. The turbulence was generated by a plate with diamond-shaped perforations mounted perpendicular to and on the leading edge of the flat plate. Unlike conventional grid turbulence studies, this perforated plate had a finite height, and this height was explored as a key independent parameter. Instantaneous velocity measurements were performed with a 1D hot-wire anemometer to reveal the behavior of the flow a short distance downstream of the perforated plate (X/D = 10-30). Different perforated plate heights (H = 3, 7, 11 cm) and free stream velocities (U = 4.5, 5.5, 6.5 m/s) have been studied

Effect of a Triangular Rib on a Flat Plate Boundary Layer

The flow structure downstream of a triangular rib over a thin plate placed in a wind tunnel was experimentally investigated using a boundary layer hotwire anemometer. Flow and boundary layer characteristics, such as thickness, shape, and turbulence parameters, were studied at different freestream velocities and streamwise locations corresponding to ReX of 1.7 × 104-2.8 × 105 for plates without and with a leading edge rib. It was found that the boundary layer of the flow over a ribbed wall was 3-3.5 times thicker and had higher turbulence intensity and smaller turbulence length scales compared to its smooth wall counterpart

Community solar PV projects

In today’s world, global warming (GW) and the resulting climate change are a significant threat to humans, plants and animals. The main contributor to GW is greenhouse gases (GHGs) that are created from the burning of fossil fuels, mainly for electrical power. Hence, the way forward in safeguarding the future of life on planet earth is to reduce on our GHG emissions and move rapidly to the utilization of renewable energy resources that are abundantly available. There are numerous advantages in implementing renewable energy projects versus the use of fossil fuels in meeting individual or community energy demands. With renewable energy, an individual or community will be able to have a more diverse and stable long-term energy supply, considering fossil fuel resources are slowly being depleted. Small-scale renewable energy projects, especially in remote communities which are currently served by diesel-generated electricity, offset the community’s use of diesel fuel. Although there will be times when renewable energy is not available and a back-up source of power is required, the long-term cost of energy may be reduced. And the use of indigenous energy can contribute to a nation (or region’s) energy security by significantly reducing its dependence on imported oil (assuming it is not an oil exporter). There are numerous renewable energy resources available globally (wind, solar, biomass, falling water, geothermal) that can be used for individual or community energy projects. Community energy projects are distinguished from other renewable energy projects in which members of the community are subscribers who use the electricity produced by the project, even though each individual does not solely own the equipment. This chapter presents an overview of how energy captured from the sun can be utilized at the community level by installing solar photovoltaic systems in the form of a solar garden or solar farm or solar power plant to generate electrical energy in meeting some, if not all, of the community total energy demand. In addition, readers will be exposed to three common ownership models and their benefits, barriers affecting the adoption of such projects and selected examples of such projects that have been completed or are in the conceptualization or construction phase within North America, Europe, South America and East Africa