Ecological impacts of Australian Ravens on bush bird communities on Rottnest Island

The Australian Raven Corvus coronoides is a predator of the eggs and nestlings of bush birds on Rottnest Island, Western Australia. Nest predation is a threatening process of island birds, and when combined with other threatening processes, such as habitat fragmentation and degradation, sustained nest predation can cause declines in bush bird communities. The terrestrial habitats on Rottnest Island have been historically fragmented through land clearing, so concern was raised by the Rottnest Island Authority regarding the impact of the Australian Raven on bush bird communities. The aims of this study were to describe the ecology of the Australian Raven on Rottnest Island, in particular the feeding ecology, and to evaluate how important bush birds are in the diet of the Australian Raven. To determine the rate of nest predation by the Australian Raven, an artificial nest experiment was conducted over four months from August to November, over six study sites. The diet of the Australian Raven was analysed by laboratory examination of raven stomach samples. In addition, observational data collected at the study sites during the study period was used to quantify the behaviour, abundance and distribution of ravens, and compared to bush bird distribution on Rottnest Island. During this study, ravens predated 20% of the artificial nests, indicating a high capacity for potential population impacts. Nest predation was confirmed by the presence of birds in the stomach contents of ravens from Rottnest, but plant material and invertebrates were found to be more important in the diet. The Australian Raven prefers the disturbed and urban habitat areas of Rottnest Island for feeding, roosting and breeding. Bush birds avoid these areas, and prefer remnant and revegetated areas. The results of this study have identified the Australian Raven as a potential predator of nesting bush birds on Rottnest Island. However, restoration of island vegetation may be having a positive effect on bush bird communities that outweighs losses of eggs and nestlings to ravens. In view of these results, continued management of the raven population is recommended as a precautionary approach so that the impacts of nest predation on bush birds are limited. Meanwhile, the population dynamics of selected bush birds can be assessed to confirm that they are recovering in response to habitat restoration programs

Defining Landscape Resistance Values in Least-Cost Connectivity Models for the Invasive Grey Squirrel: A Comparison of Approaches Using Expert-Opinion and Habitat Suitability Modelling

Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a leastcost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a leastcost approach to mapping ecological networks.This project was funded by the Forestry Commission GB and the National School of Forestry at the University of Cumbria. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Using GPS telemetry to validate least-cost modeling of gray squirrel ( Sciurus carolinensis) movement within a fragmented landscape

In Britain, the population of native red squirrels Sciurus vulgaris has suffered population declines and local extinctions. Interspecific resource competition and disease spread by the invasive gray squirrel Sciurus carolinensis are the main factors behind the decline. Gray squirrels have adapted to the British landscape so efficiently that they are widely distributed. Knowledge on how gray squirrels are using the landscape matrix and being able to predict their movements will aid management. This study is the first to use global positioning system (GPS) collars on wild gray squirrels to accurately record movements and land cover use within the landscape matrix. This data were used to validate Geographical Information System (GIS) least-cost model predictions of movements and provided much needed information on gray squirrel movement pathways and network use. Buffered least-cost paths and least-cost corridors provide predictions of the most probable movements through the landscape and are seen to perform better than the more expansive least-cost networks which include all possible movements. Applying the knowledge and methodologies gained to current gray squirrel expansion areas, such as Scotland and in Italy, will aid in the prediction of potential movement areas and therefore management of the invasive gray squirrel. The methodologies presented in this study could potentially be used in any landscape and on numerous species

Unravelling the role of α2-adrenoceptors and P2X purinoceptors in vascular sympathetic neurotransmission using a mouse lacking α1-adrenoceptors

The experiments presented in this thesis describe the roles of the post-junctional α1, α2-adrenoceptors (AR) and P2X purinoceptors in response to sympathetic nerve stimulation in mouse mesenteric and tail arteries. Such roles were determined by combining wire myography techniques and nerve stimulation alongside various selective antagonists. The influence of each receptor on the response to nerve stimulation was first defined in wild type (WT) mice before analysis of α1-AR knock out (KO) mice. Therefore the effect that genetic removal of the α1-ARs had on vascular response could be investigated. The response is the force generated in milligrams/tension when the nerves are stimulated and correspond to activation of post-junctional receptors and subsequent smooth muscle cell contraction. Systolic Blood Pressure and the α1-ARs The aim of the first study (Chapter Three) was to determine whether systolic blood pressure (BP) was different in the KO mice compared to WT controls. Tail cuff measurements of systolic BP were recorded in WT and AR KO mice. It was found that BP was not affected by loss of the α1A- and α1D¬-AR subtypes (ADKO) or by loss of all three α1-AR subtypes (α1-null). Therefore, the α1-AR role in maintaining BP may not be as crucial as previously understood or, the remaining receptors may have compensated for the loss. Calcitonin Gene Related Peptide (CGRP) in Mouse mesenteric and tail arteries The second study (Chapter Four) examined whether, under the stimulation parameters used, the potent vasodilator CGRP masked the vasoconstrictor response to nerve stimulation in mouse mesenteric and tail arteries. The potent neurotoxin capsaicin depletes the sensory nerves of CGRP. Responses prior to capsaicin incubation were compared with those following capsaicin treatment in WT, ADKO and α1-null mice. In mesenteric artery from each mouse strain, capsaicin incubation had no significant effect on the peak response to nerve stimulation. Furthermore, in the tail artery, capsaicin treatment had no significant effects on the responses in WT and α1-null mice. However, in the ADKO mouse tail artery preparations, capsaicin treatment significantly increased the peak response at low frequency stimulation. These findings may indicate an interaction between the α1-AR subtypes and the release of CGRP whereby the presence of all or none of the subtypes (WT and α1-null) has no effect on CGRP release but loss of the α1A- and α1D-AR subtypes alters the balance and reveals a CGRP induced effect. Response to perivascular nerve stimulation in Mouse mesenteric and tail arteries from Wild Type mice The aim of Chapter Five was to determine which receptors were involved in the response to nerve stimulation in mouse mesenteric and tail arteries. These results would then act as a comparison with the ADKO and α1-null responses in the later chapters. A contractile response to nerve stimulation was recorded in each of the studied vessels and abolished by combined blocked with antagonists for the α1-, α2¬-ARs and P2X receptors. Individual receptor blockade and component analysis then revealed the roles of the individual receptors. In the mesenteric arteries, the α1-ARs were the main contributors to the response followed by the P2X receptors and finally the α2-ARs which displayed both pre- and post-junctional effects. No interactions were discovered between the α1-ARs and the other receptors. The P2X receptors initiated the contraction and prolonged the response at the low frequency and contributed to the contractile response at the high frequency. In the tail artery, the α2-ARs were the dominant receptors but required the presence of the α1-ARs, and to some extent the P2X receptors in order to produce a full contractile response upon activation. The P2X receptors alone initiated the response at low frequency stimulation with both α1-ARs and P2X receptors involved in initiation of the contraction at the high frequency. Response to perivascular nerve stimulation in mesenteric and tail arteries from mice lacking α1A- and α1D-AR subtypes (ADKO) Chapter Six determined the role of the α1B-ARs in the response to nerve stimulation and therefore examined whether loss of the α1A- and α1D-AR subtypes (ADKO) affected the response. In the mesenteric arteries, at the low frequency, there was a potential interaction between the receptors. However, no single receptor was responsible for the contraction although there was a trend for the P2X receptors to be active at the beginning of the response and the α2-ARs to be active at the latter stage of the response. This was also true at the higher frequency. The ADKO vessels displayed no evidence of pre-junctional α2-ARs. In the mesenteric arteries, there is little role for the α1B-ARs. The overall contribution in the tail artery was reduced in the ADKO, particularly at the higher frequency. Similar to the WT mice, the α2-ARs were the main contributor to the response. The P2X receptors initiated the contraction but required the α2-ARs to be active at the low frequency. The α1B-ARs also required an interaction with the other receptors at low frequency stimulation in order to contribute to the initiation of the response. The α1B-ARs also contributed to the initiation of the response at the high frequency without requiring the presence of the other receptors. Response to perivascular nerve stimulation in mesenteric and tail arteries from mice lacking α1A-, α1B- and α1D-AR subtypes (α1-null) In the final study (Chapter Seven), α1-null mice were utilised in order to determine whether loss of the α1-ARs had a significant effect on the response to nerve stimulation in mouse mesenteric and tail arteries. Furthermore, the influence of the α2-ARs and P2X receptors were compared with the response in the WT vessels to determine whether they compensate for the loss of the α1-ARs. The removal of the α1-ARs dramatically reduced the response to nerve stimulation in the mesenteric arteries, with no apparent compensation from the α2-ARs or P2X receptors. There was no evidence of pre-junctional α2-ARs. The small response recorded at the high frequency was initiated by the P2X receptors and maintained by the α2-ARs and P2X receptors. The tail artery response was smaller in the α1-null mice compared with WT, particularly at the higher frequency. However, the response was still mediated largely by the α2-ARs with an interaction with the P2X receptors likely. A potential compensatory mechanism was recorded at the lower frequency as the response to P2X receptor antagonism was greater in the α1-null than in the WT mice. As was shown in the WT, activation of the P2X receptors initiated the contraction, particularly at the high frequency. Findings and Results Collectively, the findings of the studies presented in this thesis demonstrate that the α1-, α2-ARs and P2X receptors are involved in the response to nerve stimulation in the mouse mesenteric and tail arteries. Genetic removal of the α1-ARs in the ADKO and α1-null is most effective in the mesenteric arteries with little evidence of any compensatory mechanisms. In the mouse tail artery, the α2-ARs are the main contributors to the response and so loss of the α1-ARs has less of an effect. Interactions between the receptors were most clearly shown in the tail artery with little interaction between the α1-ARs and the other receptors demonstrated in the mesentery. Furthermore, it has been demonstrated here that systolic BP is unaffected in the KO mice and there is little input from the CGRP nerves using the parameters tested. From these results, the importance of α1-AR activation in nerve mediated responses was determined. The absence of a compensatory mechanism to match the response lost in the ADKO and α1-null mice, and the presentation of a normal BP alongside the survival of these transgenic mice challenges the importance of the α1-ARs being crucial in the maintenance of vascular tone. This therefore complements the knowledge that treatment of primary hypertension with α1-AR antagonists is largely unsuccessful. The contractile response mediated by α2-ARs and P2X receptors may be used as potential therapeutic targets in controlling hypertension

Dynamic Reconfiguration of the Language Network Preceding Onset of Speech in Picture Naming

Peer reviewe

Pursuing Inclusion and Justice While Affirming the Mental Health of Marginalized Students

This article provides best practices that instructors can use to affirm and support marginalized students’ mental health with a specific focus on students of color. Recently, campuses have witnessed renewed calls for diversity and inclusion in the wake of anti-Black violence. Advocates have called for needed structural changes. To build upon these calls for change, this article provides instructors with tools they can use in the interim to navigate questions of diversity, inclusion, and justice in the classroom. The essay centers the mental health needs of students from marginalized populations to hedge against the possibility that efforts to foster inclusion, including advocating for structural reform, contribute additional trauma to these students

Solving ARC visual analogies with neural embeddings and vector arithmetic: A generalized method

Analogical reasoning derives information from known relations and generalizes this information to similar yet unfamiliar situations. One of the first generalized ways in which deep learning models were able to solve verbal analogies was through vector arithmetic of word embeddings, essentially relating words that were mapped to a vector space (e.g., king - man + woman = __?). In comparison, most attempts to solve visual analogies are still predominantly task-specific and less generalizable. This project focuses on visual analogical reasoning and applies the initial generalized mechanism used to solve verbal analogies to the visual realm. Taking the Abstraction and Reasoning Corpus (ARC) as an example to investigate visual analogy solving, we use a variational autoencoder (VAE) to transform ARC items into low-dimensional latent vectors, analogous to the word embeddings used in the verbal approaches. Through simple vector arithmetic, underlying rules of ARC items are discovered and used to solve them. Results indicate that the approach works well on simple items with fewer dimensions (i.e., few colors used, uniform shapes), similar input-to-output examples, and high reconstruction accuracy on the VAE. Predictions on more complex items showed stronger deviations from expected outputs, although, predictions still often approximated parts of the item's rule set. Error patterns indicated that the model works as intended. On the official ARC paradigm, the model achieved a score of 2% (cf. current world record is 21%) and on ConceptARC it scored 8.8%. Although the methodology proposed involves basic dimensionality reduction techniques and standard vector arithmetic, this approach demonstrates promising outcomes on ARC and can easily be generalized to other abstract visual reasoning tasks.Comment: Data and code can be found on https://github.com/foger3/ARC_DeepLearnin

Third graders’ verbal reports of multiplication strategy use: How valid are they?

This study investigates whether children’s verbal reports accurately represent their thinking processes when solving simple multiplication problems. A total of 106 third graders in Dutch mainstream primary schools solved simple multiplication problems and retrospectively reported how they had done this. The degree to which verbal reports predict children’s problem-solving performance in ways that correspond to known patterns of response latency, accuracy, errors and strategy choice was assessed. The analyses took account of relevant problem characteristics and child cognitive characteristics (i.e., math ability, verbal ability, phonological decoding speed) known to affect the relation between strategy use and multiplication performance. The verbal reports were largely consistent with known patterns, supporting the use of verbal reports in assessing multiplication strategy use. Moreover, verbal reports provide valuable information that can alert teachers and educational researchers to specific issues that students face when solving simple multiplication problems. Considerations for soliciting reliable verbal reports are suggested

Dynamic telomerase gene suppression via network effects of GSK3 inhibition

<b>Background</b>: Telomerase controls telomere homeostasis and cell immortality and is a promising anti-cancer target, but few small molecule telomerase inhibitors have been developed. Reactivated transcription of the catalytic subunit hTERT in cancer cells controls telomerase expression. Better understanding of upstream pathways is critical for effective anti-telomerase therapeutics and may reveal new targets to inhibit hTERT expression. <b>Methodology/Principal Findings</b>: In a focused promoter screen, several GSK3 inhibitors suppressed hTERT reporter activity. GSK3 inhibition using 6-bromoindirubin-3′-oxime suppressed hTERT expression, telomerase activity and telomere length in several cancer cell lines and growth and hTERT expression in ovarian cancer xenografts. Microarray analysis, network modelling and oligonucleotide binding assays suggested that multiple transcription factors were affected. Extensive remodelling involving Sp1, STAT3, c-Myc, NFκB, and p53 occurred at the endogenous hTERT promoter. RNAi screening of the hTERT promoter revealed multiple kinase genes which affect the hTERT promoter, potentially acting through these factors. Prolonged inhibitor treatments caused dynamic expression both of hTERT and of c-Jun, p53, STAT3, AR and c-Myc. <b>Conclusions/Significance</b>: Our results indicate that GSK3 activates hTERT expression in cancer cells and contributes to telomere length homeostasis. GSK3 inhibition is a clinical strategy for several chronic diseases. These results imply that it may also be useful in cancer therapy. However, the complex network effects we show here have implications for either setting