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Young stellar objects (YSOs) are protostars that exhibit bipolar outflows fed by accretion disks. Theories of the transition between disk and outflow often involve a complex magnetic field structure thought to be created by the disk coiling field lines at the jet base; however, due to limited resolution, these theories cannot be confirmed with observation and thus may benefit from laboratory astrophysics studies. We create a dynamically similar laboratory system by driving a $\sim$1 MA current pulse with a 200 ns rise through a $\approx$2 mm-tall Al cylindrical wire array mounted to a three-dimensional (3-D)-printed, stainless steel scaffolding. This system creates a plasma that converges on the centre axis and ejects cm-scale bipolar outflows. Depending on the chosen 3-D-printed load path, the system may be designed to push the ablated plasma flow radially inwards or off-axis to make rotation. In this paper, we present results from the simplest iteration of the load which generates radially converging streams that launch non-rotating jets. The temperature, velocity and density of the radial inflows and axial outflows are characterized using interferometry, gated optical and ultraviolet imaging, and Thomson scattering diagnostics. We show that experimental measurements of the Reynolds number and sonic Mach number in three different stages of the experiment scale favourably to the observed properties of YSO jets with $Re\sim 10^5\unicode{x2013}10^9$ and $M\sim 1\unicode{x2013}10$, while our magnetic Reynolds number of $Re_M\sim 1\unicode{x2013}15$ indicates that the magnetic field diffuses out of our plasma over multiple hydrodynamical time scales. We compare our results with 3-D numerical simulations in the PERSEUS extended magnetohydrodynamics code.
From early on, infants show a preference for infant-directed speech (IDS) over adult-directed speech (ADS), and exposure to IDS has been correlated with language outcome measures such as vocabulary. The present multi-laboratory study explores this issue by investigating whether there is a link between early preference for IDS and later vocabulary size. Infants’ preference for IDS was tested as part of the ManyBabies 1 project, and follow-up CDI data were collected from a subsample of this dataset at 18 and 24 months. A total of 341 (18 months) and 327 (24 months) infants were tested across 21 laboratories. In neither preregistered analyses with North American and UK English, nor exploratory analyses with a larger sample did we find evidence for a relation between IDS preference and later vocabulary. We discuss implications of this finding in light of recent work suggesting that IDS preference measured in the laboratory has low test-retest reliability.
While mentors can learn general strategies for effective mentoring, existing mentorship curricula do not comprehensively address how to support marginalized mentees, including LGBTQIA+ mentees. After identifying best mentoring practices and existing evidence-based curricula, we adapted these to create the Harvard Sexual and Gender Minority Health Mentoring Program. The primary goal was to address the needs of underrepresented health professionals in two overlapping groups: (1) LGBTQIA+ mentees and (2) any mentees focused on LGBTQIA+ health. An inaugural cohort (N = 12) of early-, mid-, and late-career faculty piloted this curriculum in spring 2022 during six 90-minute sessions. We evaluated the program using confidential surveys after each session and at the program’s conclusion as well as with focus groups. Faculty were highly satisfied with the program and reported skill gains and behavioral changes. Our findings suggest this novel curriculum can effectively prepare mentors to support mentees with identities different from their own; the whole curriculum, or parts, could be integrated into other trainings to enhance inclusive mentoring. Our adaptations are also a model for how mentorship curricula can be tailored to a particular focus (i.e., LGBTQIA+ health). Ideally, such mentor trainings can help create more inclusive environments throughout academic medicine.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Eight species of the Gobiidae were recorded in weekly samples taken between July 1972 and June 1977 from the intake screens of Oldbury Power Station in the inner Severn Estuary. Buenia jeffreysii, Aphia minuta, Gobius paganellus and Gobius niger occurred infrequently and Crystallogobius linearis was only common in the late spring and summer of 1975 and 1976. Pomatoschistus microps, which peaked in numbers in the winter, increased in abundance each year between 1972 and 1977. The most numerous gobies were those belonging to the Pomatoschistus minutus complex which were separated into P. minutus and P. lozanoi only between June 1974 and July 1975. Seasonal trends in the abundance of these two species were similar, with elevated numbers occurring between July and September 1974 and in January 1975. Gonadosomatic indices and other data indicate that the decline in numbers after the latter month represented an emigration to spawning areas further down the estuary or in the Bristol Channel. Although P. minutus attained a larger body size than P. lozanoi, both these species and P. microps typically had a one year life cycle with only a small number of individuals surviving for a further few months. The fecundity of P. lozanoi, which ranged from 410–2453 (mean 1270), was lower than that reported for P. minutus in this and other studies. Analysis of stomach contents showed that the diet of both species was similar, consisting predominantly of gammarids and mysids. While both species were infected with Ligula intestinalis, the incidence of infection and the parasite index was greater in P. lozanoi than in P. minutus.
A range of “single source” Sr-Nb and Sr-Ta heterometal alkoxides precursors are investigated as potential sources for liquid injection MOCVD (metalorganic chemical vapour deposition) and ALD (atomic layer deposition) of SrBi2Ta2O9 (SBT) and SrBi2(TxNb1-x)2O9 (SBTN). These “single source” precursors are designed to alleviate the mis-match between conventional Sr and Ta or Sr and Nb sources. Strontium-tantalate and strontium-niobate thin films were deposited on silicon using the “single source” alkoxide precursors [Sr{Ta(OEt)5(dmae}2] and [Sr{Nb(OEt)5(dmae)}2] (dmae = OCH2CH2NMe2), and the optimum temperatures for deposition of stoichiometric SrTa2O6 and SrNb2O6 were determined. Separate ALD studies of [Sr{Ta(OEt)5(dmae)}2] and [Sr{Ta(OEt)5(mee)}2] (mee = OCH2CH2OMe) for the growth of strontium-tantalate were carried out to assess precursor suitability for this technique. Liquid injection MOCVD of Bi-oxide films using Bi(mmp)3 indicates similar decomposition behaviour to the Sr-Ta and Sr-Nb alkoxides, demonstrating its suitability as a complementary source of Bi for SBT, SBN and SBTN.
The principles embodied in the Nonproliferation Treaty (NPT) and the strengthening of the nonproliferation regime internationally, including Africa, would serve international peace and security. Nonproliferation is an area of common interest between the U.S. and the U.S.S.R., in which the two countries have a good record of cooperation.
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