Cerebral Vasomotor Reactivity: Impact of Hyperventilation Induced Hypocapnia on Hypercapnia Induced Vasodilation

Cerebral vasomotor reactivity (CVMR; the relationship of cerebral blood flow responses to changes in arterial carbon dioxide (PCO2)) is used to assess cerebral vascular function. CVMR is generally assessed during either steady-state or transient breathe-by-breathe changes in PCO2. In the transient method, a brief period of hyperventilation hypocapnia is often followed by hypercapnic rebreathing to induce a wide range of change in PCO2 to assess the capacity of CVMR. Assessment of CVMR during transient changes in PCO2 has been reported to be about 30% lower than that under steady-state conditions. One possibility for this discrepancy is that cerebral vasoconstriction during hyperventilation immediately before rebreathing may attenuate cerebral vasodilation and thus, CBF responses during the subsequent hypercapnic rebreathing. PURPOSE: To test the hypothesis that CVMR during rebreathing hypercapnia would be blunted when the rebreathing is preceded by a period of hyperventilation. METHODS: End-tidal carbon dioxide (PETCO2), middle cerebral artery blood velocity (CBFV), cerebral vascular conductance (CVCI; CBFV/mean arterial pressure) and CVMR (slope of the linear regression between changes in CBFV and CVCI vs. PETCO2) were assessed in 8 healthy individuals. CVMR was assessed twice, once immediately following a brief period of hyperventilation (hyperventilation for 1 min + rebreathe 4 min) and once during rebreathing only (rebreathe). The trials were counterbalanced and randomized with a minimum of 15 min elapsing between the protocols. RESULTS: The slope of the linear regression for CBFV vs. PETCO2 was reduced during hyperventilation + rebreathe relative to rebreathe only (hyperventilation + rebreathe: 3.16 ± 0.97 % / Torr, R = 0.93 ± 0.05; rebreathe: 5.03 ± 1.11 % / Torr, R = 0.83 ± 0.25; P CONCLUSION: These results indicate that hyperventilation induced hypocapnia attenuates the cerebral vasodilatory responses during a subsequent period of rebreathing induced hypercapnia

Adrenergic Control of the Cutaneous Circulation during Cryotherapy

Cryotherapy application is a widely clinically used therapeutic technique using ice or cold water applied to the skin surface to reduce local blood flow. While beneficial, cryotherapy treatment does have the potential to induce some detrimental physiological side effects. For example, cryotherapy treatment induces pronounced tissue ischemia that is sustained for hours even during a post-treatment rewarming period. PURPOSE: To investigate the role of adrenergic receptor activation on cutaneous blood flow during 30 min of cryotherapy as well as during the subsequent 1 hr of passive rewarming. We hypothesized that adrenergic-mediated vasoconstriction is involved in pronounced and sustained cutaneous vasoconstriction that occurs during cooling and passive rewarming. METHODS: To date 4 complete data sets have been collected with 2 partial, incomplete datasets. A commercially available cryotherapy unit with a water perfused bladder was used. The bladder was placed on the lateral portion of the calf. Four microdialysis membranes were threaded through the dermis of the skin directly underneath the water bladder. One site was perfused with lactated ringers solution (CON), one with bretylium tosylate (BRE), one with propranolol+yohimbine+BIBP (PBY), and one with propranolol+BIBP (PB). Skin temperature (SkT) and skin vascular conductance (SkVC) was measured at each site. Subjects had 0 °C water perfused through the cryotherapy bladder for 30 min, followed by passive rewarming (i.e. water shut off) for 1 hr, followed by direct heating with 46 °C for 10 min. RESULTS: SkT fell from 33°C to 17.7°C during 30 min of cold water application across all sites. SkVC at CON was reduced ~80% after 30 min of cooling and was not significantly different than PB (p\u3e0.05). Vasoconstriction was attenuated at the BRE and PBY sites during cooling compared the control (SkVC: BRE = 58% reduction, PBY = 37% reduction, CON 80% reduction (p0.05). CONCLUSION: Our preliminary finding was that adrenergic function mediates the vasoconstriction that occurs with cryotherapy application. This is in line with previous literature investigating the adrenergic mechanisms of vasoconstriction with skin cooling

Aquatic macroinvertebrate responses to native and non-native predators

Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus), sympatric native crayfish (Austropotamobius pallipes), and novel invasive crayfish (Pacifastacus leniusculus). G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P. jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts

Remote Extraction of Latent Fingerprints (RELF)

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordLatent fingerprints are the kind left on objects after direct contact with a person’s finger, often unwittingly at crime scenes. Most current techniques for extracting these types of fingerprint are invasive and involve contaminating the fingerprint with chemicals which often renders the fingerprint unusable for further forensic testing. We propose a novel and robust method for extracting latent fingerprints from surfaces without the addition of contaminants or chemicals to the evidence. We show our technique works on notoriously difficult to image surfaces, using off-the-shelf cameras and statistical analysis. In particular, we extract images of latent fingerprints from surfaces which are transparent, curved and specular such as glass lightbulbs and jars, which are challenging due to the curvature of the surface. Our method produces results comparable to more invasive methods and leaves the fingerprint sample unaffected for further forensic analysis. Our technique uses machine learning to identify partial fingerprints between successive images and mosaics them

A strategic framework for social impact assessment : an application to greenhouse gas mitigation strategies in Canadian prairie agriculture

Social Impact Assessment (SIA) is the process of assessing the social consequences that are likely to follow specific policy actions or project development. SIA has not been widely adopted and is said to be the ‘orphan’ of the assessment process. Using Environmental Assessment (EA) however, there are two primary limitations to EA: first, EA is inherently biased toward the biophysical environment, and social impacts, when considered, are only considered in an indirect or secondary manner; second, EA is targeted at the project level, where many alternatives that may have met the larger goals have been rejected. These limitations are reflected in Canada’s agricultural sector where SIAs are rarely, if ever, undertaken. Agriculture is responsible for approximately ten percent of total greenhouse gas (GHG) emissions in Canada, and several better management practices (BMP) have been suggested for managing these emissions in Canadian agriculture. However, there has not been a strategic assessment of the on-farm socioeconomic effects of such programs, nor the geographic implications of a ‘one-size-fits-all’ policy solution. This paper presents a ‘higher level’ strategic assessment of alternative policy options for managing greenhouse gas emissions in Canadian agriculture. Data are collected using a stakeholder survey assessment, and the process is guided by a seven-phase strategic environmental assessment framework. Using this strategic framework, the on-farm social impacts of alternative greenhouse gas mitigation programs are assessed. Data are aggregated using multi-criteria weighting techniques. Stakeholder preference structures for the alternatives set are identified as well, the results of the SIA identified adoption of zero till practices as the most socially acceptable alternative. The research results suggest that a ‘one-size-fits-all’ GHG mitigation policy would not be acceptable from a social perspective. The implications of include such issues as: the applicability of regional policies based on soil zone, alternatives to governmental ‘top down’ hierarchical’ policies, and the necessity for collaboration and meaningful dialogue between on-farm individuals and policy makers. Adoption of a GHG mitigation policy in Canada will require education and collaboration between all affected stakeholders and decision makers. The application of a strategic framework illustrates how the SIA process is enhanced when an assessment is completed at the plan, policy, and program level – it enables proactive consideration of the social effects on par with the biophysical effects, and it facilitates consideration of a broad range of alternatives, in support of sustainable development principles

Robust autoregression: Student-t innovations using variational Bayes

Copyright © 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Autoregression (AR) is a tool commonly used to understand and predict time series data. Traditionally the excitation noise is modelled as a Gaussian. However, real-world data may not be Gaussian in nature, and it is known that Gaussian models are adversely affected by the presence of outliers. We introduce a Bayesian AR model in which the excitation noise is assumed to be Student-t distributed. Variational Bayesian approximations to the posterior distributions of the model parameters are used to overcome the intractable integrations inherent in the Bayesian model. Independent automatic relevance determination (ARD) priors over each of the AR coefficients are used to estimate the model order. Using synthetic data, we show that the Student-t model performs well against both Gaussian and leptokurtic data, in terms of parameter estimation (including the model order) and is much more robust to outliers than either Gaussian or finite mixtures of Gaussian models. We apply the model to strongly leptokurtic EEG signals and show that the Student-t model makes more accurate one-step-ahead predictions than the Gaussian model and provides more consistent estimates of the AR coefficients over simultaneously recorded EEG channels

Transcriptome sequencing, annotation and polymorphism detection in the hop bush, Dodonaea viscosa

The hop bush, Dodonaea viscosa, is a trans-oceanic species distributed oversix continents. It evolved in Australia where it is found over a wide range of habitat types and is an ecologically important species. Limited genomic resources are currently available for this species, thus our understanding of its evolutionary history and ecological adaptation is restricted. Here, we present a comprehensive transcriptome dataset for future genomic studies into this species.We performed Illumina sequencing of cDNA prepared from leaf tissue collected from seven populations of D. viscosa ssp. angustissima and spatulata distributed along an environmental gradient in South Australia. Sequenced reads were assembled to provide a transcriptome resource. Contiguous sequences (contigs) were annotated using BLAST searches against the NCBI non-redundant database and gene ontology definitions were assigned. Single nucleotide polymorphisms were detected for the establishment of a genetic marker set. A comparison between the two subspecies was also carried out.Illumina sequencing returned 268,672,818 sequence reads, which were de novoassembled into 105,125 contigs. Contigs with significant BLAST alignments (E value < 1e(-5))numbered at 44,191, with 38,311 of these having their most significant hits to sequences from land plant species. Gene Ontology terms were assigned to 28,440 contigs and KEGG analysis identified 146 pathways that the gene products from 5,070 contigs are potentially involved in. The subspecies comparison identified 8,494 fixed SNP differences across 3,979 contiguous sequences, indicating a level of genetic differentiation between them. Across all samples, 248,235 SNPs were detected.We have established a significant genomic data resource for D. viscosa,providing a comprehensive transcriptomic reference. Genetic differences among morphologically distinct subspecies were found. A wide range of putative gene regions were identified along with a large set of variable SNP markers, providing a basis for studies into the evolution and ecological adaptation of D. viscosa.Matthew J. Christmas, Ed Biffin and Andrew J. Low

Targeted capture to assess neutral genomic variation in the narrow-leaf hopbush across a continental biodiversity refugium

The Adelaide geosyncline, a mountainous region in central southern Australia, is purported to be an important continental refugium for Mediterranean and semi-arid Australian biota, yet few population genetic studies have been conducted to test this theory. Here, we focus on a plant species distributed widely throughout the region, the narrow-leaf hopbush, Dodonaea viscosa ssp. angustissima, and examine its genetic diversity and population structure. We used a hybrid-capture target enrichment technique to selectively sequence over 700 genes from 89 individuals across 17 sampling locations. We compared 815 single nucleotide polymorphisms among individuals and populations to investigate population genetic structure. Three distinct genetic clusters were identified; a Flinders/Gammon ranges cluster, an Eastern cluster, and a Kangaroo Island cluster. Higher genetic diversity was identified in the Flinders/Gammon Ranges cluster, indicating that this area is likely to have acted as a refugium during past climate oscillations. We discuss these findings and consider the historical range dynamics of these populations. We also provide methodological considerations for population genomics studies that aim to use novel genomic approaches (such as target capture methods) on non-model systems. The application of our findings to restoration of this species across the region are also considered.Matthew J. Christmas, Ed Biffin, Martin F. Breed & Andrew J. Low