A novel landscape ecology approach for determining microhabitat correlations and faunal patchiness in extreme environments:pilot study for the Southern East Pacific Rise at 17-18° S

Since their discovery in 1977, hydrothermal vent communities have offered scientists a unique glimpse into a world that is supported primarily by chemically derived energy rather than direct energy from the sun. Furthermore, studies of hydrothermal vent ecosystems have introduced scientists to amazing animals that have successfully adapted to living in extreme environments. Although much has been learned about the life histories of vent organisms, due to the difficulty and expense of performing large scale (spatial and temporal) studies at deep sea hydrothermal vent sites, our knowledge of vent faunal dynamics is largely based on observational studies that often lack the support of sound statistical analysis. Furthermore, data sets can be discordant in space and time, making it difficult to piece together the potentially complex life histories of vent animals. The main goal of this report is to study the applicability of point pattern analysis, a simple spatial statistical method based on principles of landscape ecology, for characterizing the distributions of organisms at hydrothermal vent sites. The study began as a pilot project, and has focused on an existing high resolution, remotely sensed, data set from the superfast-spreading southern East Pacific Rise at 17-18° South (Figure 1). It was accomplished through an integration of remote sensing technology, landscape ecology principles, and geographic information science

Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49\ub74% (95% uncertainty interval [UI] 46\ub74–52\ub70). The TFR decreased from 4\ub77 livebirths (4\ub75–4\ub79) to 2\ub74 livebirths (2\ub72–2\ub75), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83\ub78 million people per year since 1985. The global population increased by 197\ub72% (193\ub73–200\ub78) since 1950, from 2\ub76 billion (2\ub75–2\ub76) to 7\ub76 billion (7\ub74–7\ub79) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2\ub70%; this rate then remained nearly constant until 1970 and then decreased to 1\ub71% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2\ub75% in 1963 to 0\ub77% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2\ub77%. The global average age increased from 26\ub76 years in 1950 to 32\ub71 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59\ub79% to 65\ub73%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1\ub70 livebirths (95% UI 0\ub79–1\ub72) in Cyprus to a high of 7\ub71 livebirths (6\ub78–7\ub74) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0\ub708 livebirths (0\ub707–0\ub709) in South Korea to 2\ub74 livebirths (2\ub72–2\ub76) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0\ub73 livebirths (0\ub73–0\ub74) in Puerto Rico to a high of 3\ub71 livebirths (3\ub70–3\ub72) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2\ub70% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation

Non-viral xylosyltransferase-1 siRNA delivery as an effective alternative to chondroitinase in an in vitro model of reactive astrocytes

Reactive astrocytosis and the subsequent glial scar is ubiquitous to injuries of the central nervous system, especially spinal cord injury (SCI) and primarily serves to protect against further damage, but is also a prominent inhibitor of regeneration. Manipulating the glial scar by targeting chondroitin sulfate proteoglycans (CSPGs) has been the focus of much study as a means to improve axon regeneration and subsequently functional recovery. In this study we investigate the ability of small interfering RNA (siRNA) delivered by a non-viral polymer vector to silence the rate limiting enzyme involved in CSPG synthesis. Gene expression of this enzyme, xylosyltransferase-1, was silenced by 65% in Neu7 astrocytes which conferred a reduced expression of CSPGs. Furthermore, conditioned medium taken from treated Neu7s, or co-culture experiments with dorsal root ganglia (DRG) showed that siRNA treatment resulted in a more permissive environment for DRG neurite outgrowth than treatment with chondroitinase ABC alone. These results indicate that there is a role for targeted siRNA therapy using polymeric vectors to facilitate regeneration of injured axons following central nervous system injury. (C) 2016 IBRO. Published by Elsevier Ltd. All rights reserved.The authors would like to thank Science Foundation Ireland for financial assistance under Grant no. 07/SRC/B1163.peer-reviewe

Boxplots showing levels of explanatory variables determined to significantly explain survival to 28 d for fish that survived 7 d and had recorded metrics on surgical wounds.

Results are for estimated fitted values from a linear mixed effects model evaluated by AIC. Boxplots of the fitted estimated survival values show median values surrounded by a box of the 25th to 75th percentiles (i.e. interquartile range) with whiskers at the outlying values, which are 1.5 times the interquartile range extended from the median.</p

Pushing the envelope: Micro-transmitter effects on small juvenile Chinook salmon (Oncorhynchus tshawytscha).

Significant effort has been invested in downsizing telemetry transmitters so they can be used to monitor survival and behavior in a variety of fish species and life stages. Commercially available "micro" transmitters in particular have presented researchers with the opportunity to tag very small fish (< 250 mm fork length). We conducted a release/recapture study in tandem with a laboratory study of tag effects on juvenile yearling spring and subyearling fall Chinook salmon (Oncorhynchus tshawytscha). Fish surgically implanted with both a micro-acoustic transmitter and passive integrated transponder (PIT) tags were compared with fish injected with only a PIT tag. Detections from both tag types showed that during the downstream migration, fish surgically implanted with both a micro-acoustic transmitter and PIT tag did not survive at the same rate or behave in the same manner as those injected with only a PIT tag. Differences in survival were more pronounced in subyearlings than in yearlings. This was likely due to warmer temperatures experienced by migrating subyearlings, their higher metabolic rate, and their smaller size and consequently higher tag-burden. To identify the mechanisms driving these differences, we necropsied migrating study fish recaptured at locations 225-460 km downstream from the release site. Results revealed that compared with PIT-tagged fish, micro-acoustic-tagged fish had heightened inflammatory responses within the body cavity, delayed healing of surgical incision sites, and poor body-condition. For study fish tagged along with those released to the river but held in the laboratory for observation, outcomes revealed that tag effects were similar in direction, but not as pronounced under artificial conditions

List of metrics used to evaluate incision site healing for dip study fish that survived the 24‑h post‑tagging recovery period and transport to the Bonneville fish facility.

List of metrics used to evaluate incision site healing for dip study fish that survived the 24‑h post‑tagging recovery period and transport to the Bonneville fish facility.</p

Rank among surgeons based on percentage mortality for study replicates 1–8.

Mean and overall rank scores are also listed; a lower ranking corresponds with higher mortality. (DOCX)</p

Average survival for subyearling Chinook salmon (<i>Oncorhynchus tshawytscha</i>) held at Bonneville Dam by treatment (all replicates combined) at 7, 14, 21, and 28 d.

Average survival for subyearling Chinook salmon (Oncorhynchus tshawytscha) held at Bonneville Dam by treatment (all replicates combined) at 7, 14, 21, and 28 d.</p

Number of fish tagged by treatment and date.

In an attempt to develop more effective surgical implantation methods for fish, surgical incisions typical of those made for implanting micro-acoustic transmitters into the peritoneal cavity were evaluated on a weekly basis for healing progression using a suite of metrics. Additionally, four chemicals were evaluated at concentrations commonly used in aquaculture for their ability to prevent surgical site infection and thus to promote incision healing and survival. Chemical treatments included hydrogen peroxide (25, 50, and 100 mg l-1), salt (10 and 30 ppt), Argentyne (1:1, Argentyne:water), and PolyAqua (1/2 tsp 36 l-1). For all study fish, the presence of two intact sutures seven days post-surgery (generally associated with good suturing technique) was negatively correlated with survival. A generalized linear mixed effects model indicated that suture presence, increasing tagging temperature, and the presence of foreign material on sutures decreased survival by 0.56, 0.72 and 0.60 respectively. Conversely, evidence of suture tearing and increasing fork length at tagging increased survival by 0.24 and 0.17. The antiseptic treatments tested promoted neither faster healing of surgical incisions nor higher survival for fish held for 28 days compared to a reference group and two of the chemicals may be contraindicated for prophylactic use at published doses. These findings underscore the need for researchers to adopt a decidedly cautious approach to planning and interpretation of study outcomes that rely on telemetry tagging, carefully considering the study subjects, potential effects of the techniques used, and implications of the environmental conditions experienced.</div

Nonparametric Kaplan-Meier estimated mortality for treatments pooled across replicates 1–8.

The mortality curves for the three peroxide treatments were very similar, therefore they were pooled for this analysis. The two salt treatments were also pooled due to having very similar mortality curves.</p