Assessing the invasion potential of non-native branchiobdellidans: experimental studies of survival, reproduction and competition

The impact of invasive species on the recipient ecosystem can be strongly influenced by the presence of associated symbionts. It is therefore important to evaluate the likelihood of co-introduced symbiont establishment, and this requires an understanding of their life history traits. Here, we investigate survival, reproduction and competition in two non-native branchiobdellidan ectosymbionts (Xironogiton victoriensis and Cambarincola aff. okadai) on invasive signal crayfish (Pacifastacus leniusculus). In vivo, X. victoriensis established viable infrapopulations within 10 weeks, whereas C. aff. okadai went extinct within 2 weeks. Both X. victoriensis and C. aff. okadai deposited cocoons in vivo that hatched in 10–27 and 10–11 days, respectively. In vitro, X. victoriensis and C. aff. okadai survived for over 13 and 15 weeks respectively, although both were negatively affected by increased temperature and nitrate, and were absent from kick samples taken in the field. Only C. aff. okadai deposited cocoons in vitro, and this larger species readily predated on X. victoriensis but not vice versa. Both branchiobdellidans possess traits associated with colonisation success, including a relatively fast reproductive rate and extended off-host survival. Given its survival in vivo and known detrimental effect on signal crayfish X. victoriensis is perhaps more likely to influence host invasion dynamics, although its persistence may be affected by the presence of co-occurring symbionts

Influence of parking on train station choice under uncertainty for park-and-ride users

This paper presents a station choice model for park and ride (PnR) users based on uncertain parking attributes, such as parking search time (PST). In order to take into account uncertainty in PnR users’ choice process, a mixed logit model was developed within the framework of the discrete choice theory, the utility function in the model was established using a mean-variance approach under the cumulative prospect theory framework proposed Tversky and Kahneman [1]. A stated preference survey was designed for studying PnR users’ preference of stations, which was influenced by parking conditions at a train station. The experimental design was optimized using the D-optimality criterion. Our results show that the number that parking bays left in PnR facilities at given access time, parking cost including parking fees and fines and the variation of PST are important factors affecting PnR users’ station choice. PnR users were risk averse toward the variation of PST, which means that a PnR user is willing to choose a station with less uncertain or variation of PS

Energy transfer in turbulence under rotation

It is known that rapidly rotating turbulent flows are characterized by the emergence of simultaneous upscale and downscale energy transfer. Indeed, both numerics and experiments show the formation of large-scale anisotropic vortices together with the development of small-scale dissipative structures. However the organization of interactions leading to this complex dynamics remains unclear. Two different mechanisms are known to be able to transfer energy upscale in a turbulent flow. The first is characterized by two-dimensional interactions among triads lying on the two-dimensional, three-component (2D3C) manifold, namely on the Fourier plane perpendicular to the rotation axis. The second mechanism is three-dimensional and consists of interactions between triads with the same sign of helicity (homochiral). Here, we present a detailed numerical study of rotating flows using a suite of high Reynolds number direct numerical simulations within different parameter regimes to analyze both upscale and downscale cascade ranges. We find that the upscale cascade at wave numbers close to the forcing scale is generated by increasingly dominant homochiral interactions which couple the three-dimensional bulk and the 2D3C plane. This coupling produces an accumulation of energy in the 2D3C plane, which then transfers energy to smaller wave numbers thanks to the two-dimensional mechanism. In the forward cascade range, we find that the energy transfer is dominated by heterochiral triads and is dominated primarily by interaction within the fast manifold where $k_z\ne0$. We further analyze the energy transfer in different regions in the real-space domain. In particular, we distinguish high-strain from high-vorticity regions and we uncover that while the mean transfer is produced inside regions of strain, the rare but extreme events of energy transfer occur primarily inside the large-scale column vortices

Agrobiodiversity, Rural Transformations and Household Experiences of Globalised Change: A Case Study from Southern Bolivia

This paper examines reconfigurations of household economies and agrobiodiversity through the experiences and responses of rural households to local manifestations of globalisation and environmental change in the Central Valley of Tarija, Bolivia, from the 1950s to the present. Research participant narratives from seven study communities document a widely experienced regional shift from rain-fed agriculture and pastured livestock production for household consumption to market-oriented production of regionally-specialised commodities. Particularly important to this reconfiguration are changing land access and use regimes, household responses to changing opportunities, discourses and social requirements related with ‘modernising lifestyles’, market integration and dependence, changing environmental and ecological conditions, and greater availability of consumer goods and technologies. We analyse how these processes have combined to reconfigure the range of livelihood possibilities available to rural households, or their ‘landscapes of possibility’, in ways that favour transition to specialised commodity production. Patterns of change in household agrobiodiversity use, however, are entwined with threads of persistence, underscoring the contingent nature of rural transitions and the role of local agency and creativity in responding to and sometimes shaping how globalisation unfolds. Examining rural transition through the experiences of households in particular contexts over time offers insights for development policy and practice to support producers’ ability to respond to globalisation and environmental change in ways they see as desirable and beneficial to their livelihoods and wellbeing

Expression and genomic organization of zonadhesin-like genes in three species of fish give insight into the evolutionary history of a mosaic protein

BACKGROUND: The mosaic sperm protein zonadhesin (ZAN) has been characterized in mammals and is implicated in species-specific egg-sperm binding interactions. The genomic structure and testes-specific expression of zonadhesin is known for many mammalian species. All zonadhesin genes characterized to date consist of meprin A5 antigen receptor tyrosine phosphatase mu (MAM) domains, mucin tandem repeats, and von Willebrand (VWD) adhesion domains. Here we investigate the genomic structure and expression of zonadhesin-like genes in three species of fish. RESULTS: The cDNA and corresponding genomic locus of a zonadhesin-like gene (zlg) in Atlantic salmon (Salmo salar) were sequenced. Zlg is similar in adhesion domain content to mammalian zonadhesin; however, the domain order is altered. Analysis of puffer fish (Takifugu rubripes) and zebrafish (Danio rerio) sequence data identified zonadhesin (zan) genes that share the same domain order, content, and a conserved syntenic relationship with mammalian zonadhesin. A zonadhesin-like gene in D. rerio was also identified. Unlike mammalian zonadhesin, D. rerio zan and S. salar zlg were expressed in the gut and not in the testes. CONCLUSION: We characterized likely orthologs of zonadhesin in both T. rubripes and D. rerio and uncovered zonadhesin-like genes in S. salar and D. rerio. Each of these genes contains MAM, mucin, and VWD domains. While these domains are associated with several proteins that show prominent gut expression, their combination is unique to zonadhesin and zonadhesin-like genes in vertebrates. The expression patterns of fish zonadhesin and zonadhesin-like genes suggest that the reproductive role of zonadhesin evolved later in the mammalian lineage

Readmission to intensive care: development of a nomogram for individualising risk

Background: Readmission to intensive care during the same hospital stay has been associated with a greater risk of in-hospital mortality and has been suggested as a marker ofquality of care. There is lack of published research attempting to develop clinical prediction tools that individualise the risk of readmission to the intensive care unit during the same hospital stay. Objective: To develop a prediction model using an inception cohort of patients surviving an initial ICU stay. Design, setting and participants: The study was conducted at Liverpool Hospital, Sydney. An inception cohort of 14 952 patients aged 15 years or more surviving an initial ICU stay and transferred to general wards in the study hospital between 1 January 1997 and 31 December 2007 was used to develop the model. Binary logistic regression was used to develop the prediction model and anomogram was derived to individualise the risk of readmission to the ICU during the same hospital stay. Main outcome measure: Readmission to the ICU during the same hospital stay.Results: Among members of the study cohort there were 987 readmissions to ICU during the study period. Compared with patients not readmitted to the ICU, patients who were readmitted were more likely to have had ICU stays of at least 7 days (odds ratio [OR], 2.2 [95% CI, 1.85-2.56]); non-elective initial admission to the ICU (OR, 1.7[95% CI, 1.44-2.08]); and acute renal failure (OR, 1.6 [95%CI, 0.97-2.47]). Patients admitted to the ICU from the operating theatre or recovery ward had a lower risk of readmission to ICU than those admitted from general wards, the emergency department or other hospitals. The maximum error between observed frequencies and predicted probabilities of readmission to ICU was estimatedto be 3%. The area under the receiver operating characteristic curve of the final model was 0.66.Conclusion: We have developed a practical clinical tool toindividualise the risk of readmission to the ICU during the same hospital stay in patients who survive an initial episodeof intensive care

Molecular markers applied to evaluation of environmental services in the araucaria forest in Southern Brazil.

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