FROM GENES TO SPECIES: ECOLOGICAL SPECIATION WITH GENE FLOW IN \u3cem\u3eNEODIPRION PINETUM\u3c/em\u3e AND \u3cem\u3eN. LECONTEI\u3c/em\u3e

My dissertation focuses on how differences accumulate across the genome during ecological speciation with geneflow. To do this I used two species of Neodiprionpine sawflies, which are plant-feeding hymenopterans with high host specificity. I used experimental crosses to measure both intrinsic and extrinsic postzygotic isolation and to understand the contribution of specific traits to reproductive isolation. Despite substantial genetic divergence and haploid males in which all recessive incompatibilities should be expressed, I found surprisingly little evidence of intrinsic postzygotic isolation. Recombination in hybrid males may reconstitute viable genotypes and counteract the effects of haploidy in males. Nevertheless, hybrids have drastically reduced fitness due to intermediate host-use traits causing strong extrinsic postzygotic isolation. Together, these results suggest that divergent selection on host-use traits is the primary driver of speciation in these, and likely other, plant-feeding insects. Next, I performed a QTL mapping study of the traits under divergent selection that contribute to extrinsic postzygotic isolation to understand how genetic architecture can constrain or promote speciation and adaptation. I found that opposing dominance between host-choice and host-use traits composes the genetic basis of the earlier detected extrinsic postzygotic isolation. This opposing dominance is part of a growing body of work showing that trait mismatch and not hybrid intermediacy is typically how extrinsic postzygotic isolation is formed. My fourth chapter focuses on how haplodiploid sex determination shapes how populations accumulate differences across the genome during speciation. Using a combination of demographic analysis of pine sawflies, population genetic simulations, and a meta-analysis, I found that compared to diploids, haplodiploids have predictably higher and more variable differentiation across the genome when they diverge in the presence of gene flow. Overall, Neodiprion sawflies present a great opportunity to better understand the genetics of adaptation and speciation

Oviposition Traits Generate Extrinsic Postzygotic Isolation Between Two Pine Sawfly Species

Background: Although empirical data indicate that ecological speciation is prevalent in nature, the relative importance of different forms of reproductive isolation and the traits generating reproductive isolation remain unclear. To address these questions, we examined a pair of ecologically divergent pine-sawfly species: while Neodiprion pinetum specializes on a thin-needled pine (Pinus strobus), N. lecontei utilizes thicker-needled pines. We hypothesized that extrinsic postzygotic isolation is generated by oviposition traits. To test this hypothesis, we assayed ovipositor morphology, oviposition behavior, and host-dependent oviposition success in both species and in F1 and backcross females. Results: Compared to N. lecontei, N. pinetum females preferred P. strobus more strongly, had smaller ovipositors, and laid fewer eggs per needle. Additionally, we observed host- and trait-dependent reductions in oviposition success in F1 and backcross females. Hybrid females that had pinetum-like host preference (P. strobus) and lecontei-like oviposition traits (morphology and egg pattern) fared especially poorly. Conclusions: Together, these data indicate that maladaptive combinations of oviposition traits in hybrids contribute to extrinsic postzygotic isolation between N. lecontei and N. pinetum, suggesting that oviposition traits may be an important driver of divergence in phytophagous insects

Dealing with Complexity: Infant Feeding Choices and Experiences for Mothers with Infants in Neonatal Intensive Care Units and Transitional Care Wards

EXECUTIVE SUMMARY The central aim of the research on which this document reports was: To explore the knowledge, perceptions and experiences of infant feeding of mothers with infants in neonatal intensive care units (NICU) and transitional care wards (TCW) and the support these mothers receive from healthcare professionals and significant others with the aim of contributing to further support of mothers, significant others and healthcare professionals in the future. The objectives were: 1. To explore mothers’ with infants in NICU knowledge and understanding of infant, feeding and how this influences feeding choices. 2. To gain an understanding of mothers experiences of infant feeding, 3. To investigate the challenges of infant feeding in NICU. 4. To explore the significance of their self-identity and perception as ‘good’ or ‘not so good’ mothers in relation to this choice. 5. To ascertain the support women receive from healthcare professionals and significant others. 6. To identify further research needs, develop service provision and inform practice and policy. Background to the study is supported by a review of the clinical and sociologically relevant literature and brief detail on a previous related study (Stenhouse and Letherby 2013) which focused on the experience of mothers’ whose pregnancies were complicated by diabetes. A mixed method ethnographic approach was adopted: • Observations in the NICU and TCW were undertaken (alongside interviewing) amounting to approximately six hours. • One-to-one and dyad/group interviewing were undertaken with mothers and some of their partners. • Questionnaires (consisting of 10 questions, some of which were open to allow more respondent input) were distributed to all healthcare professionals working in NICU and TCW. An audit involving a systematic and independent examination of maternal and infant notes was undertaken at the same time as the primary data was collected. DATA AND DISCUSSION The Audit: This section provides a snapshot of infant feeding and expression of breastmilk from a cohort of mothers and babies who had previously been cared for in NICU, TCW or both. Appendix IV is a copy of a poster presented as part of the Medical Training Special Studies Unit. Interview and Questionnaire Data: This section reports on data collected from women, significant others and healthcare professionals and includes detailed reference to the significance of ‘The Journey’, the mixed experience of ‘Skills and Support’ and the experiences of ‘Pleasure, Pressure and Propaganda’. CONCLUSIONS, IMPLICATIONS AND RECOMMENDATIONS Six summary points 1. Training for staff is mixed and this is linked to confidence in supporting women. 2. Women ‘sensed’ the lack of confidence of some staff and this caused anxiety i.e. if the combination of staff on a shift had little experience/knowledge. 3. Women recognised that certain occupation groups had more time and experience to support them i.e. nursery nurses on TCW, midwives on NICU. 4. The physical environment was an issue for respondents. For example: a. TCW privacy, or not, when expressing and feeding. b. In NICU screens used for expressing or feeding sometimes caused anxiety given that screens are also used when baby is poorly/undergoing a procedure. 5. In TCW, formula feed was linked to early discharge resulting in some experiencing subtle pressure to formula feed. 6. Community outreach team very supportive to some and women respondents felt they would have benefited from longer support. Six recommendations 1. Training needs to be consistent for all grades of staff and a whole day annually is preferred by healthcare professional respondents. 2. Release from service essential to ensure training is undertaken and given the high priority it deserves. 3. Different coloured screens for expressing/feeding AND for procedures would be beneficial and reduce stress for mothers and significant others. 4. Active recruitment of peer supporters with experience of having a baby in NICU. 5. Ensure continued support from peer supporters when moving from breastfeeding to formula feeding. 6. More information related to equipment available in the community on discharge i.e. hospital grade breast pumps

Wildfire and climate impacts tree hollow density in a temperate Australian forest

Tree hollows are an important landscape resource used by fauna for shelter, nesting, and predator avoidance. In fire-prone landscapes, wildfire and climate may impact hollow dynamics; however, assessments of their concurrent impacts are rare. We conducted a field survey at 80 sites in the Sydney Basin bioregion (Australia) to understand how fire frequency, fire severity, mean annual temperature, and mean annual precipitation concurrently impacted the site-density of small- (10 cm entry width) tree hollows and tree basal scars (which mediate hollow formation via invertebrate access to heartwood), when tree-size and dead/live status were considered. A unimodal relationship occurred between medium- and large-sized hollow densities and fire frequency and severity, respectively, with hollow densities greatest at intermediate frequencies/severities. Increases of 1.82, 1.43, and 1.17 hollows per site were observed between the 1 (reference) and 2, 2 and 3, and 3 and >3 fire frequency categories. Increases of 1.26, 1.75 and 0.75 hollows per site were observed between the low (reference) and moderate, moderate and high, and high and very high fire severity categories. Fire severity was also positively associated with basal scar density, with increases of 2.52, 8.15, and 8.47 trees per site between the low (reference) and moderate, moderate and high, and high and very high categories. A weak positive and stronger negative association was observed between mean annual temperature and small-sized hollow and basal scar density, respectively. Dead and medium-sized tree density was positively associated with medium-sized hollow and basal scar tree density, respectively. Collectively, our results suggest that wildfires, and in some cases climate, have diverse and size-specific impacts on tree hollow and basal scar density. Our results imply that fire regimes that allow for moderately severe wildfire will promote larger-sized tree hollows, which are a limiting resource for many fauna species

Force and energy dissipation variations in non-contact atomic force spectroscopy on composite carbon nanotube systems

UHV dynamic force and energy dissipation spectroscopy in non-contact atomic force microscopy were used to probe specific interactions with composite systems formed by encapsulating inorganic compounds inside single-walled carbon nanotubes. It is found that forces due to nano-scale van der Waals interaction can be made to decrease by combining an Ag core and a carbon nanotube shell in the Ag@SWNT system. This specific behaviour was attributed to a significantly different effective dielectric function compared to the individual constituents, evaluated using a simple core-shell optical model. Energy dissipation measurements showed that by filling dissipation increases, explained here by softening of C-C bonds resulting in a more deformable nanotube cage. Thus, filled and unfilled nanotubes can be discriminated based on force and dissipation measurements. These findings have two different implications for potential applications: tuning the effective optical properties and tuning the interaction force for molecular absorption by appropriately choosing the filling with respect to the nanotube.Comment: 22 pages, 6 figure

Endothelial-specific Nox2 overexpression increases vascular superoxide and macrophage recruitment in ApoE−/− mice

AIMS: Vascular disease states are associated with endothelial dysfunction and increased production of reactive oxygen species derived from NADPH oxidases. However, it remains unclear whether a primary increase in superoxide production specifically in the endothelium alters the initiation or progression of atherosclerosis. METHODS AND RESULTS: Mice overexpressing Nox2 specifically in the endothelium (Nox2-Tg) were crossed with ApoE(-/-) mice to produce Nox2-Tg ApoE(-/-) mice and ApoE(-/-) littermates. Endothelial overexpression of Nox2 in ApoE(-/-) mice did not alter blood pressure, but significantly increased vascular superoxide production compared with ApoE(-/-) littermates, measured using both lucigenin chemiluminescence and 2-hydroxyethidium production (ApoE(-/-), 19.9 ± 6.3 vs. Nox2-Tg ApoE(-/-), 47.0 ± 7.0 nmol 2-hydroxyethidium/aorta, P< 0.05). Increased endothelial superoxide production increased endothelial levels of vascular cell adhesion protein 1 and enhanced macrophage recruitment in early lesions in the aortic roots of 9-week-old mice, indicating increased atherosclerotic plaque initiation. However, endothelial-specific Nox2 overexpression did not alter native or angiotensin II-driven atherosclerosis in either the aortic root or the descending aorta. CONCLUSION: Endothelial-targeted Nox2 overexpression in ApoE(-/-) mice is sufficient to increase vascular superoxide production and increase macrophage recruitment possible via activation of endothelial cells. However, this initial increase in macrophage recruitment did not alter the progression of atherosclerosis. These results indicate that Nox-mediated reactive oxygen species signalling has important cell-specific and distinct temporal roles in the initiation and progression of atherosclerosis

Expression of plastocyanin and cytochrome f of the cyanobacterium Phormidium laminosum in escherichia coli and Paracoccus denitrificans and the role of leader peptides

Macromolecular Biochemistr

Severe and Short Interval Fires Rearrange Dry Forest Fuel Arrays in South-Eastern Australia

Fire regimes have shaped extant vegetation communities, and subsequently fuel arrays, in fire-prone landscapes. Understanding how resilient fuel arrays are to fire regime attributes will be key for future fire management actions, given global fire regime shifts. We use a network of 63-field sites across the Sydney Basin Bioregion (Australia) to quantify how fire interval (short: last three fires 10 years apart) and severity (low: understorey canopy scorched, high: understorey and overstorey canopy scorched), impacted fuel attribute values 2.5 years after Australia’s 2019–2020 Black Summer fires. Tree bark fuel hazard, herbaceous (near-surface fuels; grasses, sedges <50 cm height) fuel hazard, and ground litter (surface fuels) fuel cover and load were higher in areas burned by low- rather than high-severity fire. Conversely, midstorey (elevated fuels: shrubs, trees 50 cm–200 m in height) fuel cover and hazard were higher in areas burned by high- rather than low-severity fire. Elevated fuel cover, vertical connectivity, height and fuel hazard were also higher at long rather than short fire intervals. Our results provide strong evidence that fire regimes rearrange fuel arrays in the years following fire, which suggests that future fire regime shifts may alter fuel states, with important implications for fuel and fire management

Broadband 180 degree universal rotation pulses for NMR spectroscopy designed by optimal control

Broadband inversion pulses that rotate all magnetization components 180 degrees about a given fixed axis are necessary for refocusing and mixing in high-resolution NMR spectroscopy. The relative merits of various methodologies for generating pulses suitable for broadband refocusing are considered. The de novo design of 180 degree universal rotation pulses using optimal control can provide improved performance compared to schemes which construct refocusing pulses as composites of existing pulses. The advantages of broadband universal rotation by optimized pulses (BURBOP) are most evident for pulse design that includes tolerance to RF inhomogeneity or miscalibration. We present new modifications of the optimal control algorithm that incorporate symmetry principles and relax conservative limits on peak RF pulse amplitude for short time periods that pose no threat to the probe. We apply them to generate a set of pulses suitable for widespread use in Carbon-13 spectroscopy on the majority of available probes