ORCID Profile
0000-0002-8412-4945
Current Organisation
University of Oxford
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Publisher: Oxford University Press (OUP)
Date: 10-05-2023
Abstract: We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z & 7 galaxies in the Early Release Observations JWST/NIRCam and JWST/NIRSpec data of the SMACS J0723.3−7327 cluster. We use the Bayesian spectral energy distribution-fitting code prospector with a flexible star formation history (SFH), a variable dust attenuation law, and a self-consistent model of nebular emission (continuum and emission lines). Importantly, we self-consistently fit both the emission line fluxes from JWST/NIRSpec and the broad-band photometry from JWST/NIRCam, taking into account slit-loss effects. We find that these three z=7.6–8.5 galaxies (M⋆ ≈ 108 M⊙) are young with rising SFHs and mass-weighted ages of 3–4 Myr, though we find indications for underlying older stellar populations. The inferred gas-phase metallicities broadly agree with the direct metallicity estimates from the auroral lines. The galaxy with the lowest gas-phase metallicity (Zgas= 0.06 Z⊙) has a steeply rising SFH, is very compact (& .2 kpc), and has a high star formation rate surface density (ΣSFR ≈ 22 M⊙ yr−1 kpc−2), consistent with rapid gas accretion. The two other objects with higher gas-phase metallicities show more complex multicomponent morphologies on kpc scales, indicating that their recent increase in star formation rate is driven by mergers or internal, gravitational instabilities. We discuss effects of assuming different SFH priors or only fitting the photometric data. Our analysis highlights the strength and importance of combining JWST imaging and spectroscopy for fully assessing the nature of galaxies at the earliest epochs.
Publisher: MDPI AG
Date: 05-03-2022
DOI: 10.3390/ANI12050658
Abstract: The morphological measures, crown-to-rump length (CR), and abdominal circumference (AC) have been suggested to be as good, if not better, than birth weight for predicting piglet performance. We explored the relationships between CR and AC, and piglet weights at birth and 24 h, to investigate their predictive value for piglet survival. Piglet weight and AC at birth and 24 h, and CR at 24 h were recorded for 373 piglets born to 31 sows. Morphological measures were categorised into two levels for weight and three levels for AC and CR. Further, AC and CR groupings were concatenated to create a new variable (PigProp) to describe the proportionality of piglet morphology. Proportionate piglets had equal CR and AC levels, and disproportionate piglets had contrasting levels. Birth AC was a good predictor of colostrum intake (p 0.001) when accounting for birth weight, but 24 h weight and PigProp were good indicators of actual colostrum intake (p 0.001 for both). The significant interaction of colostrum and PigProp showed that within the smaller piglet groups, those who had greater than 200 g of colostrum had higher 24 h weight and survival (p 0.001 both). As expected, as body weight and colostrum intake increased, so did weight change to d 21 (P = 0.03 and trend at p = 0.1, respectively). A similar pattern was seen with increasing PigProp group (p 0.001) however, piglets from the disproportionate group 1,3 had the greatest observed weight change (5.15 ± 0.06 kg). Our data show morphological measures may be more predictive of piglet viability in terms of both performance and survival than weight and there may be subgroups that have higher than expected chances of survival.
Publisher: Informa UK Limited
Date: 06-03-2023
Publisher: MDPI AG
Date: 06-10-2021
DOI: 10.3390/ANI11102902
Abstract: Increased attention on the effects of the global push for a larger litter size has focused on the increased occurrence of piglets with decreased viability, which have lighter birthweights and a reduced ability to thrive in early life. To improve their odds of survival, interventions must be timely and targeted. This requires the early identification of low-viability pigs and appropriate strategies to manage them. Using novel measures such as abdominal circumference and crown to the rump length in conjunction with birth weight may provide an improved protocol for the identification of those at most risk of preweaning mortality. Further, identifying these at-risk piglets allows interventions to increase their colostrum intake and heat provisions shortly following birth. The appropriate management of the pre- and post-partum sows will improve the chances of decreasing the number of piglets born with lower viability. However, this outcome is constrained by limitations in resources such as technology and staffing. If these challenges can be overcome, it will allow for greater control and increased effectiveness in the implementation of current and new management strategies.
Publisher: MDPI AG
Date: 19-10-2023
DOI: 10.3390/ANI13203259
Publisher: American Astronomical Society
Date: 12-2022
Abstract: We compare 500 pc scale, resolved observations of ionized and molecular gas for the z ∼ 0.02 starbursting disk galaxy IRAS08339+6517, using measurements from KCWI and NOEMA. We explore the relationship of the star-formation-driven ionized gas outflows with colocated galaxy properties. We find a roughly linear relationship between the outflow mass flux ( Σ ̇ out ) and star formation rate surface density (Σ SFR ), Σ ̇ out ∝ Σ SFR 1.06 ± 0.10 , and a strong correlation between Σ ̇ out and the gas depletion time, such that Σ ̇ out ∝ t dep − 1.1 ± 0.06 . Moreover, we find these outflows are so-called breakout outflows, according to the relationship between the gas fraction and disk kinematics. Assuming that ionized outflow mass scales with total outflow mass, our observations suggest that the regions of highest Σ SFR in IRAS08 are removing more gas via the outflow than through the conversion of gas into stars. Our results are consistent with a picture in which the outflow limits the ability of a region of a disk to maintain short depletion times. Our results underline the need for resolved observations of outflows in more galaxies.
Publisher: American Astronomical Society
Date: 30-08-2021
Publisher: MDPI AG
Date: 10-11-2020
DOI: 10.3390/ANI10112080
Abstract: The backfat of pig carcasses is greater in spring than summer in Australia. The unexplained seasonal variation in carcass backfat creates complications for pig producers in supplying consistent lean carcasses. As a novel explanation, we hypothesised that the increased carcass fatness in spring was due to a greater percentage of born-light progeny from sows that were mated in summer and experienced hot conditions during early gestation. The first part of our experiment compared the birth weight of piglets born to the sows mated in summer (February, the Southern Hemisphere) with those born to sows mated in autumn (May the Southern Hemisphere), and the second part of the experiment compared the growth performance and carcass fatness of the progeny that were stratified as born-light (0.7–1.1 kg) and born-normal (1.3–1.7 kg) from the sows mated in these two seasons. The results showed that the sows mated in summer experienced hotter conditions during early gestation as evidenced by an increased respiration rate and rectal temperature, compared with those mated in autumn. The sows mated in summer had a greater proportion of piglets that were born ≤1.1 kg (24.2% vs. 15.8%, p 0.001), lower average piglet birth weight (1.39 kg vs. 1.52 kg, p 0.001), lower total litter weights (18.9 kg vs. 19.5 kg, p = 0.044) and lower average placental weight (0.26 vs. 0.31 kg, p = 0.011) than those mated in autumn, although litter sizes were similar. Feed intake and growth rate of progeny from 14 weeks of age to slaughter (101 kg live weight) were greater for the born-normal than born-light pigs within the progeny from sows mated in autumn, but there was no difference between the born-light and normal progeny from sows mated in summer, as evidenced by the interaction between piglet birth weight and sow mating season (Both p 0.05). Only the born-light piglets from the sows mated in summer had a greater backfat thickness and loin fat% than the progeny from the sows mated in autumn, as evidenced by a trend of interaction between piglet birth weight and sow mating season (Both p 0.10). In conclusion, the increased proportion of born-light piglets (0.7–1.1 kg range) from the sows mated in summer contributed to the increased carcass fatness observed in spring.
Publisher: MDPI AG
Date: 16-01-2021
DOI: 10.3390/ANI11010214
Abstract: Previous positive interactions with humans may ameliorate the stress response of farm animals to aversive routine practices such as painful or stressful procedures, particularly those associated with stockpeople. We studied the effects of positive handling by providing younger (parity 1–2) and older (parity 3–8) sows housed in pens of fifteen (n = 24 pens in total) with either positive human contact (+HC) or routine human contact (control) during gestation. The +HC treatment involved a familiar stockperson patting and scratching sows and was imposed at a pen-level for 2 min daily. Measurements studied included behavioural, physiological and productivity variables. The +HC sows showed reduced avoidance of the stockperson conducting pregnancy testing and vaccination in the home pens, however the behavioural and cortisol responses of sows in a standard unfamiliar human approach test did not differ. There were no effects of +HC on aggression between sows, serum cortisol or serum brain-derived neurotrophic factor concentrations during gestation, or on the behavioural and cortisol response to being moved to farrowing crates. There were also no effects of +HC on the maternal responsiveness of sows, farrowing rate or the number of piglets born alive, stillborn or weaned. Sows in the +HC pens reduced their physical interaction with the stockpeople imposing the treatment after 2 weeks, which suggests the sows may have habituated to the novel or possible rewarding elements of the handling treatment. This experiment shows that regular positive interaction with stockpeople does reduce sows’ fear of stockpeople, but does not always confer stress resilence.
Publisher: MDPI AG
Date: 30-05-2021
DOI: 10.3390/ANI11061619
Abstract: This experiment studied the effects of lactation housing systems and human interaction on piglets’ responses to routine stressors. Forty litters of piglets were reared in either a standard farrowing crate (FC) or a loose farrowing and lactation pen (LP PigSAFE pen) and received either routine contact with humans (C) or regular opportunities for positive human contact (+HC 3 min of patting, stroking and scratching 5 times/week). Behavioural and physiological responses to routine husbandry procedures, weaning, novelty and humans were studied in addition to effects on piglet growth, injuries and survival. Compared to C piglets, +HC piglets vocalised for shorter durations (p = 0.018) during husbandry procedures and showed a lower intensity of escape behaviour during iron injection (p = 0.042) and oral vaccination (p = 0.026) at 3 d of age, capture at 2 wk of age (p 0.001), and intramuscular vaccination (p = 0.005) at 3 wk of age. +HC piglets at 2 wk of age were faster than C piglets to approach (p = 0.048) and interact (p = 0.042) with a stationary unfamiliar human. Compared to LP piglets, FC piglets showed a lower intensity of escape behaviour during capture and iron administration by a stockperson at 3 d of age (p = 0.043). FC piglets at 2 wk of age were faster than LP piglets to approach (p = 0.005) and interact (p = 0.027) with a novel object and approach (p = 0.009) and interact (p = 0.008) with an unfamiliar human. FC piglets had fewer injuries than LP piglets at 2 wk of age (p = 0.004). +HC pigs had fewer injuries than C pigs after weaning (p = 0.003). After weaning there were more pigs from LP than FC observed to be upright (both stationary, p = 0.002 and walking, p = 0.024), vocalizing (p = 0.004), nosing another pig (p = 0.035) and nosing the pen floor (p = 0.038). There were no significant effects on neutrophil:lymphocyte ratios or plasma cortisol concentrations 1.5 h after weaning. However, 25 h after weaning +HC pigs had higher haptoglobin concentrations than C pigs (p = 0.002), and C/LP pigs had higher cortisol concentrations than +HC/LP and C/FC pigs (p = 0.012). There were no significant effects on piglet growth, the number of piglets born alive or the number stillborn, however there were more piglets weaned from FC than LP (p = 0.035). The results from this experiment raise questions that require further research on the ability of pigs reared in loose pens to cope with stressors such as exposure to humans, novelty, husbandry procedures and weaning. This experiment also provides evidence that regular positive human interaction reduces pigs’ fear of humans and husbandry procedures imposed by stockpeople. More research is required to determine if any of these effects are sustained long-term.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Rebecca Morrison.