Session A6: Timing, Frequency and Environmental Conditions Associated with Mainstem-Tributary Movement by a Lowland River Fish, Golden Perch

Abstract: Tributary and mainstem connections represent important corridors for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in southeastern Australia, using acoustic telemetry over four years. Golden perch moved freely between mainstem and tributary habitats. The results of the study indicate that a spatially and temporally complex relationship between adult golden perch movement, river discharge and water temperature plays a key role in connecting mainstem and tributary populations of the species. The relatively common occurrence of movement across the mainstem–tributary junction suggests that this geographic feature does not function as an impermeable behavioural or demographic boundary between populations in the two rivers. This finding highlights the fact that fish populations do not necessarily conform to artificially constrained management units, and demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across riverscapes. Although they are often complex, the behavioural mechanisms and associated environmental conditions that influence connectivity across mainstem– tributary interfaces need to be understood and accounted for during development of models that underpin management actions for riverine fishes

Vacuum-UV negative photoion spectroscopy of CH4

Using synchrotron radiation in the range 12-35 eV, negative ions are detected by mass spectrometry following vacuum-UV photoexcitation of methane. Ion yields for H$^-$, CH$^-$ and CH$_2^-$ are recorded, the spectra of CH$^-$ and CH$_2^-$ for the first time. All ions display a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation. Cross sections for ion-pair formation are put onto an absolute scale by calibrating the signal strengths with those of F$^-$ from SF$_6$ and CF$_4$. Following normalisation to total vacuum-UV absorption cross sections, quantum yields for anion production are reported. There is a major discrepancy in the H$^-$ cross section with an earlier measurement, which remains unresolved. The anions arise from both direct and indirect ion-pair mechanisms. For a generic polyatomic molecule AB, the former is defined as AB $\rightarrow$ A$^-$ + B$^+$ (+ neutrals), the latter as the predissociative crossing of an initially-excited Rydberg state of AB by an ion-pair state. In a separate experiment, the threshold photoelectron spectrum of the second valence band of CH$_4$, ionisation to CH$_4^+$ A $^2$A$_1$ at 22.4 eV, is recorded with an instrumental resolution of 0.004 eV; many of the Rydberg states observed in indirect ion-pair formation converge to this state. The widths of the peaks are lifetime limited, increasing with increasing $v$ in the $v_1$ (a$_1$) vibrational ladder. They are the first direct measurement of an upper value to the dissociation rate of these levels into fragment ions

Experimental multi-scale characterization of mode-II interlaminar fracture in geometrically scaled stitched and unstitched resin-infused composites

This work is focused on investigating the impact of out-of-plane stitches on enhancing mode-II interlaminar fracture toughness (or energy) and characterizing damage progression and crack arrestment in stitched resin-infused composites. For the experimental work, End-Notched Flexure (ENF) quasi-isotropic specimens were manufactured using +/-45 non-crimp carbon-fiber fabrics through a resin-infusion process. Both stitched and unstitched specimen sets were designed for comparison. For a size effect study, the ENF specimens were geometrically scaled with three scaling levels. Based on the load-displacement data (i.e., global analysis), the fracture energy of the specimen material was analyzed using the compliance calibration method and a size effect theory. The fracture energy values were compared between the stitched and unstitched cases to characterize the enhanced fracture toughness of stitched composites. For local analysis, two types of digital image correlation (DIC) systems were employed: microscopic and macroscopic (i.e., coupon-scale) DIC systems. By analyzing in-plane displacement through the thickness, separation development was characterized along predicted fracture process zones. The impact of out-of-plane stitches on separation propagation along fracture process zones was discussed based on the DIC analysis. This work will contribute to developing a high-fidelity damage model for stitched resin-infused composites in the form of a traction-separation for high-speed aircraft applications

Assessing the Relevancy of National Culture in Predicting the Efficacy of Constraints in the Information Systems Consulting Domain

Opportunism is present in professional services and, as a result, organizations adopt mechanisms to constrain it. Despite the work on constraining opportunistic consultants, researchers have generally ignored the potential impact of national culture on the efficacy of constraint mechanisms. Using the theory of relationship constraints (TRC), this study examines the effectiveness of different constraint mechanisms for information systems (IS) consultants in the United States and China based on different levels of information asymmetry, tacit and explicit knowledge. While we found support in both cultures for the salience of these dimensions, we also found important distinctions for the effectiveness of different constraints between the cultures. Legal constraints are more effective in China while social constraints are more effective in the United States. While TRC is relevant in both cultures, national culture moderates the effectiveness of various constraint mechanisms and highlights the need for additional study

Timing, frequency and environmental conditions associated with mainstem-tributary movement by a lowland river fish, golden perch (Macquaria ambigua)

Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers

Effect of rhizome exposure to contrasting abiotic conditions on the performance of the invasive macrophyte Hedychium coronarium J. Koenig (Zingiberaceae)

Although invasive species are often better competitors than native species, broad environmental tolerance may also drive invasion success. Tolerance to abiotic heterogeneity in riparian ecosystems tends to favour the establishment of alien clonal species, as well as their dispersion by vegetative fragments. Hedychium coronarium J. Koenig is a rhizomatous emergent macrophyte native to Asia and has invaded Neotropical riparian ecosystems. We assessed the effect of H. coronarium rhizome exposure to distinct abiotic conditions on ramet growth. We exposed rhizomes to different desiccation periods (1–90 days), temperatures (15, 25 and 35 °C), and light regimes (0, 12, 16 h) and then assessed the effect of each of these variables on subsequent clonal growth (aboveground biomass production per plant and per ramet, and number and height of ramets) under ambient conditions. While no rhizome survived desiccation periods longer than 30 days, ramet growth among surviving rhizomes was not affected by the period of desiccation. Biomass production per rhizome, ramet biomass, and ramet height were significantly lower at 35 °C than at 25 °C. Constant darkness increased rhizome survival, but decreased ramet growth. Although rhizome exposure to extremes of each abiotic variable may hinder the invasion success of H. coronarium, the subsequent aboveground biomass production of surviving rhizomes did not decrease strongly in response to any treatment. This resilience may contribute to successful establishment of H. coronarium after dispersal through rhizome fragments and to varying abiotic conditions

The prevalence of cannabis use disorders in people who use medicinal cannabis : A systematic review and meta-analysis

Background The prevalence of cannabis use disorders (CUDs) in people who use cannabis recreationally has been estimated at 22%, yet there is a dearth of literature exploring CUDs among people who use medicinal cannabis. We aimed to systematically review the prevalence of CUDs in people who use medicinal cannabis. Methods In our systematic review and meta-analysis, we followed PRISMA guidelines and searched three databases (PsychInfo, Embase and PubMed) to identify studies examining the prevalence of CUDs in people who use medicinal cannabis. Meta-analyses were calculated on the prevalence of CUDs. Prevalence estimates were pooled across different prevalence periods using the DSM-IV and DSM-5. Results We conducted a systematic review of 14 eligible publications, assessing the prevalence of CUDs, providing data for 3681 participants from five different countries. The systematic review demonstrated that demographic factors, mental health disorders and the management of chronic pain with medicinal cannabis were associated with an elevated risk of CUDs. Meta-analyses were conducted on the prevalence of CUDs. For individuals using medicinal cannabis in the past 6–12 months, the prevalence of CUDs was 29% (95% CI: 21-38%) as per DSM-5 criteria. Similar prevalence was observed using DSM-IV (24%, CI: 14–38%) for the same period. When including all prevalence periods and using the DSM-5, the prevalence of CUDs in people who use medicinal cannabis was estimated at 25% (CI: 18-33%). Conclusions The prevalence of CUDs in people who use medicinal cannabis is substantial and comparable to people who use cannabis for recreational reasons, emphasizing the need for ongoing research to monitor the prevalence of CUDs in people who use medicinal cannabis

Rocks Associated With the Mississippian-Pennsylvanian Unconformity in Southwestern Indiana

The purpose of this field conference is to acquaint participants with strata that are associated with the Mississippian-Pennsylvanian unconformity in southwestern Indiana. Criteria which aid in distinguishing between Mansfield strata of Pottsville (early Pennsylvanian) age and classic formations of Chester (late Mississippian) age will receive considerable attention in discussions at evening meetings and on the outcrop. Inspection of limestone and sandstone quarries will afford an insight into the economic products of Chester and Mansfield rocks

Rocks Associated with the Mississippian-Pennsylvanian Unconformity in Southwestern Indiana

Indiana Geological Survey Guidebook 9The purpose of this field conference is to acquaint participants with strata that are associated with the Mississippian-Pennsylvanian boundary in southwestern Indiana. Criteria which aid in distinguishing between Mansfield strata of Pottsville (early Pennsylvanian) age and clastic formations of Chester (late Mississippian) age will receive considerable attention in discussions at evening meetings and on the outcrop. Inspection of limestone and sandstone quarries will afford an insight into the economic products of Chester and Mansfield rocks. Participants may collect fossils at many of the stops.Indiana Geological Survey; Indiana Department of Conservation Department of Geology, Indiana Universit