Yr Period Research Articles

First 5-year TAVR/TAVI Outcomes from the South African SHARE-TAVI national registry and the influence of malignancy on late outcomes

Abstract Introduction The South African (SA) national prospective multicentre observational SHARE-TAVI registry aims to provide local outcomes data on all TAVIs in State & Private sectors, to support local evidence-based policy evaluations, comparing outcomes to international data & identifying local variations. Method All 20 implant centres voluntarily capture all-comers data into the web-based registry. 2266 patients from 1 Sept 2014 to 28 Feb 2022 had pre-TAVI clinical evaluations and 1502 proceeded to TAVI & had procedural data & complications (VARC2 criteria), 30d & annual follow up recorded. The 5-yr cohort of 289 patients have clinical history and profile similar to international data (Table 1). Results Procedural success of 93.43% and 1-year mortality of 15.92% in the 5-yr cohort (STS score 8.85%) are similar to reported international data in early TAVI programmes. All-cause mortality at 5-years is 44.3% (in PARTNER 1 – 67.8%, PARTNER 2.0 – 46.0%), and the greatest proportion of non-cardiac mortality (38.5%) occurs in period >1–2yr post-TAVI (lowest proportion 29.4% in >3–4yr period). Outcomes measures in a more recent 2020 patient cohort (n=219, success 98.63% and 1-yr mortality 8.85%, STS risk score 5.51%) have improved compared to the 5-yr cohort. Patients with “Prior or current malignancy” (POCM) at TAVI evaluation have increased mortality in both the 1-yr outcome (n=637) cohort, 18.7% 1-yr mortality vs 9.3% in those without POCM, and same trend in the 2-year outcome cohort n=443 (28.0% 2-year mortality vs 12.8% without malignancy). Frail patients with POCM in the 2-yr cohort have substantially higher mortality at 2 years, 34.8% than frail patients without POCM 15.9% At evaluation 66% of patients are NYHA class III+IV, post-TAVI only 5.9% at 30d & 8.8% at 1-year, at 1-year 30% of patients have maintained improvement by 2 or 3 NYHA classes. Conclusion 5-yr outcomes in SA are comparable to international data, and procedural outcomes have improved further as to be expected with maturation of the programme and technology. The NYHA class distribution at 1-yr shows improvements which should translate into improved quality of life, future studies should include patient self-reported quality of life assessments to verify this benefit. Malignancy, even if prior, may predict poorer outcomes in the longer term, possibly due to reported higher frailty in these patients. Amongst other factors, prior or current malignancy may be considered relevant when assessing patients for futility for TAVI in SA's severely constrained healthcare resource environment. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Educational and Research Grants from SA Heart Association and Medtronic, Edwards Life Sciences

Cost and emissions pathways towards net-zero climate impacts in aviation

Aviation emissions are not on a trajectory consistent with Paris Climate Agreement goals. We evaluate the extent to which fuel pathways—synthetic fuels from biomass, synthetic fuels from green hydrogen and atmospheric CO2, and the direct use of green liquid hydrogen—could lead aviation towards net-zero climate impacts. Together with continued efficiency gains and contrail avoidance, but without offsets, such an energy transition could reduce lifecycle aviation CO2 emissions by 89–94% compared with year-2019 levels, despite a 2–3-fold growth in demand by 2050. The aviation sector could manage the associated cost increases, with ticket prices rising by no more than 15% compared with a no-intervention baseline leading to demand suppression of less than 14%. These pathways will require discounted investments on the order of US$0.5–2.1 trillion over a 30 yr period. However, our pathways reduce aviation CO2-equivalent emissions by only 46–69%; more action is required to mitigate non-CO2 impacts. Decarbonization of the aviation sector is difficult due to increasing demand and the current lack of scalable mitigation technologies. This Analysis examines pathways towards a net-zero aviation system with improved fuel and aircraft technologies, efficiency gains and contrail avoidance.

On the environmental and economic issues associated with the Jatropha curcas shell gasification to heat and electricity for biodiesel production

The present work is focused on the use of Jatropha curcas biomass (shell), as feed to gasification systems coupled to a diesel engine for electricity generation. The scope of this research is to analyze the environmental and economic effects of the integration of a gasification system to a biodiesel plant. The environmental impacts are quantified by a Life Cycle Assessment and the economy is assessed based on the Net Present Value, Internal Rate of Return, Investment Recovery Period models and the Levelized cost of electricity. The results demonstrate that a gasification system, using this biomass as a source of electricity generation, is a promising alternative for energy supply, with good economic effect. Estimated efficiencies are: Net Present Value > 0, Internal Rate of Return > 10%/yr and Investment Recovery Period = 2.08 years, representing very good outcomes for this kind of system. Nevertheless, the project exhibits a very low Levelized Cost of Electricity of 0.054 USD/kWh. From the environmental point of view, there is not critical step during the whole life cycle of electricity generation from Jatropha curcas biomass.negative environmental impacts were found for breathing-inorganics and acidification-eutrophication, but both at negligible levels.

P1169: ELEVATED CRP AT INFUSION OF AXICABTAGENE CILOLEUCEL PREDICTS HIGH-GRADE CAR-T TOXICITY AND OUTPERFORMS MORE COMPLEX SCORES

Background: Predicting CRS and ICANS prior to CAR-T infusion is desirable as it may help to plan management. Two groups1,2 have recently shown that a modification of the Endothelial Activation and Stress Index (EASIX) score, developed to predict toxicity in bone marrow transplant recipients3, can predict CRS and ICANS severity in CAR-T patients, however these have not been externally validated or are difficult to apply in practice. Aims: We aimed to determine whether the EASIX or related scores could predict CAR-T toxicity in our patients and if not, then to identify other potential predictors from the available clinical information. Methods: We reviewed the medical records of adult patients who received axicabtagene ciloleucel (axi-cel) as standard of care at our centre over a 2yr period, collecting data on timing and severity of CRS and ICANS as well as baseline demographic and biochemical factors. We calculated an EASIX score for all patients and an ‘EASIX-F’ score based on the values provided by Greenbaum et al (EASIX-F1) and our own interquartile values (EASIX-F2). We then performed a linear regression of each of: the EASIX score; EASIX-F1; EASIX-F2; and other variables of interest with maximum grade of CRS, with a plan to perform a multivariate analysis with any significant variables (p<0.05). Results: 67 patients were eligible for analysis. Baseline demographics were similar to those described on the licensing trial4. On univariate analysis (UVA), neither EASIX score (p=0.10), nor either iteration of the EASIX-F score (p= 0.08 and 0.15 respectively), was associated with severity of CRS for our patients. Pre-infusion C-Reactive Protein (D0 CRP) however appeared strongly associated with CRS severity, both on UVA (p=0.001) and by multiple linear regression, where it was the only variable identified that showed any association with CRS severity (p=0.003). Given the strength of the D0 CRP and CRS association, we evaluated the association of D0 CRP with ICANS severity which was significant (p=0.012) and D0 CRP with a combined outcome of ‘high grade CAR-T toxicity’ (HGT), defined as development of either grade 3+ CRS or grade 3+ ICANS, where it was again strongly associated (p<0.001). We then dichotomised D0 CRP to determine whether we could identify a practically useful cut-off to predict HGT. We looked at D0 CRP values of ≥50, ≥100 and ≥150 individually and all cut-offs performed well with increasing likelihood of HGT with higher CRP values. With D0 CRP ≥50, probability of developing HGT was 42% vs 13% (OR 5.09, p=0.007); with CRP ≥100 it was 55% vs 14% (OR 7.2, p=0.006); and with CRP ≥150 it was 100% vs 13% (OR undefined, p<0.001). Finally, given these unexpected findings we performed a prospective review of the 19 axi-cel patients treated from our initial data-cut off to 1 Feb 2022 and found that for these patients, a D0 CRP ≥100 or ≥150 predicted HGT well. HGT incidence was 75% vs 7% (OR 42, Fisher’s p=0.016) for both cut-offs because 3 of the 4 patients with HGT had a CRP of >150 (Table 1). The single patient with HGT and D0 CRP <100 interestingly was a non-responder. For the full 86-patient cohort, D0 CRP ≥150 was the best cut-off, predicting a 90% incidence of HGT vs 12% if CRP <150 (OR 42, p<0.001). Image:Summary/Conclusion: On retrospective analysis of 67 axi-cel patients, D0 CRP was more strongly associated with CRS severity than more complex prognostic scores. D0 CRP level, especially if ≥150, showed strong association with high grade CAR-T toxicity and remained predictive in a 19-patient validation cohort. This has potential implications for management of axi-cel patients.

A new power spectrum and stochastic representation for the geomagnetic axial dipole

SUMMARY Earth’s internal magnetic field is dominated by the contribution of the axial dipole whose temporal variations are wide ranging and reflect characteristic timescales associated with geomagnetic reversals and large scale palaeosecular variation, ranging down to decadal and subannual field changes inferred from direct observations. We present a new empirical power spectrum for the axial dipole moment based on composite magnetic records of temporal variations in the axial dipole field that span the frequency range 0.1 to 5 × 105 Myr–1 (periods from 10 million to 2 yr). The new spectrum is used to build a stochastic representation for these time variations, based on an order 3 autoregressive (AR) process and placed in the context of earlier stochastic modelling studies. The AR parameter estimates depend on the frequency of transitions in the spectral regime and may be influenced by Ohmic diffusion, advection and torsional oscillations in Earth’s core. In several frequency ranges across the interval 200–5000 Myr–1(5000 to 200 yr periods) the empirical power spectrum lies above the AR3 model and may be influenced by Magneto–Coriolis (MC) waves in Earth’s core. The spectral shape and parameter estimates provide a potentially useful guide for developing assessments of whether numerical dynamo simulations meet criteria for being considered Earth like.

The Unreasonable Effectiveness of the Air-Fluorescence Technique in Determining the EAS Shower Maximum

We review all existing air-fluorescence measurements of the elongation rate of extensive air showers (slope of mean EAS shower maximum Xmax vs. log of shower energy E) above 1017 eV. We find remarkable agreement for all current and historic experiments over a 30 yr period for the energy range from 1017 to 3 × 1018 eV. The mean elongation rate in this energy interval is near 80 g/cm2/decade. Above this energy, experiments in the Northern hemisphere are in good agreement with an average elongation rate of 48 ± 10 g/cm2/decade while Southern hemisphere experiments have a flatter elongation rate of 26 ± 2 g/cm2/decade. We point out that, given the agreement at lower energies, possible systematic reasons for this difference are unlikely. Given this, the world elongation rate data alone may indicate a composition difference of UHECR in the Northern and Southern hemisphere and thus a diversity of UHECR sources in the Northern and Southern sky.

Short- and Mid-term Periodicities Observed in Neutron Monitor Counting Rates throughout Solar Cycles 20–24

Abstract This paper examines the short- and mid-term periodicities (≲2 yr) in the cosmic-ray flux along 55 yr, from 1964 to 2019. The cosmic-ray flux has been computed by averaging the counting rates, in typified units, of a set of selected neutron monitors. This builds a representative virtual neutron monitor, named the global neutron monitor. The relevant discovered periodicities are ∼13.5, ∼27, ∼46–64, ∼79–83 day; Rieger-type (∼134–190 days); ∼225–309 day; and ∼1.06–1.15, ∼1.31–1.40, and ∼1.75–2.20 yr periods. The same analyses have been applied to the sunspot number (SSN) with the aim to compare the discovered periodicities and look for possible origins of these periodicities. Two main results have been achieved: the periodicities of 77–83 days, 134–190 days (Rieger type), 225–309 days, ∼1.3 yr, and ∼1.7 yr could be related to the solar dynamo, and an inversely linear relationship has been found between the average of the SSN versus the duration time for each solar cycle of the ∼1.75–2.20 yr period.

Mid-infrared Variability of Low-redshift Active Galactic Nuclei: Constraints on a Hot Dust Component with a Variable Covering Factor

Abstract We utilize mid-infrared multiepoch data from the Wide-field Infrared Survey Explorer over a ∼10 yr period in the W1 (3.4 μm) and W2 (4.6 μm) bands to investigate the structure of dusty torus in low-redshift (0.15 &lt; z ≤ 0.4) active galactic nuclei (AGNs). We calculate a Spearman correlation coefficient (r 12) between the W1 magnitude and W1 − W2 color based on the light curve in individual objects. Interestingly, r 12 spans a broad range from −1 to 1 and is detected to be correlated with mean W1 − W2 color and AGN bolometric luminosity, in the sense that objects with a blue W1 − W2 color and low AGN luminosity tend to become redder (bluer) with increasing (decreasing) W1 brightness in the light curve (i.e., r 12 &lt; 0), although the correlation of r 12 with the bolometric luminosity is relatively weak. The fit for the spectral energy distribution reveals a significant contribution from the host galaxy in the W1 and W2 bands. However, the dependencies of r 12 on the W1 − W2 color and AGN luminosity still persist even after careful elimination of the host light contribution. We propose that this result can be explained if the covering factor of the hot dust component decreases as the AGN luminosity increases.

Interaction between chloride and both macro- and micronutrients in annual canarygrass

Annual canarygrass (Phalaris canariensis L.) has a larger response to chloride (Cl−) fertilizer than other cereal crops. This unexpected response prompted further research for unexpected interactions between Cl− and other nutrients in annual canaryseed. The objective of this study was to compare the interaction of macronutrients and micronutrients with Cl− on the development and grain yield of annual canarygrass. Thirteen fertilizer combinations were applied to determine the effect of macro- and micronutrients on annual canarygrass. A field study was conducted at six locations across Saskatchewan over a 4 yr period using a randomize complete block design. Grain yield had a strong chloride response at 7 of the 21 site years with a 70% increase in grain yield over the 7 site-years. A sideband application or surface application of Cl− were both effective. At the responsive sites without the addition of Cl−, the addition of other nutrients is not effective while at the non-responsive sites, responses to the nutrients can be achieved without the addition of Cl−. Chloride impacted canarygrass during reproductive development. Nitrogen is the major nutrient Cl− interacted with in this study. Canarygrass is not more responsive to phosphorus, potassium, sulfur, zinc, copper, manganese, and boron than other cereals. In conclusion, at Cl−-responsive sites the application of nutrients are ineffective in the absence of Cl− fertilizer. In addition, the sensitivity of annual canarygrass to Cl− indicates that it could be used to investigate the role of Cl− in cereal crop development and grain yield.

TRAPPIST-1: Dynamical analysis of the transit-timing variations and origin of the resonant chain

We analyze solutions drawn from the recently published posterior distribution of the TRAPPIST-1 system, which consists of seven Earth-size planets appearing to be in a resonant chain around a red dwarf. We show that all the planets are simultaneously in two-planet and three-planet resonances, apart from the innermost pair for which the two-planet resonant angles circulate. By means of a frequency analysis, we highlight that the transit-timing variation (TTV) signals possess a series of common periods varying from days to decades, which are also present in the variations of the dynamical variables of the system. Shorter periods (e.g., the TTVs characteristic timescale of 1.3 yr) are associated with two-planet mean-motion resonances, while longer periods arise from three-planet resonances. By use of N-body simulations with migration forces, we explore the origin of the resonant chain of TRAPPIST-1 and find that for particular disc conditions, a chain of resonances – similar to the observed one – can be formed which accurately reproduces the observed TTVs. Our analysis suggests that while the 4-yr collected data of observations hold key information on the two-planet resonant dynamics, further monitoring of TRAPPIST-1 will soon provide signatures of three-body resonances, in particular the 3.3 and 5.1 yr periodicities expected for the current best-fit solution. Additional observations would help to assess whether the innermost pair of planets is indeed resonant (its proximity to the 8:5 resonance being challenging to explain), and therefore give additional constraints on formation scenarios.

The Unanticipated Phenomenology of the Blazar PKS 2131–021: A Unique Supermassive Black Hole Binary Candidate

Abstract Most large galaxies host supermassive black holes in their nuclei and are subject to mergers, which can produce a supermassive black hole binary (SMBHB), and hence periodic signatures due to orbital motion. We report unique periodic radio flux density variations in the blazar PKS 2131−021, which strongly suggest an SMBHB with an orbital separation of ∼0.001–0.01 pc. Our 45.1 yr radio light curve shows two epochs of strong sinusoidal variation with the same period and phase to within ≲2% and ∼10%, respectively, straddling a 20 yr period when this variation was absent. Our simulated light curves accurately reproduce the “red noise” of this object, and Lomb–Scargle, weighted wavelet Z-transform and least-squares sine-wave analyses demonstrate conclusively, at the 4.6σ significance level, that the periodicity in this object is not due to random fluctuations in flux density. The observed period translates to 2.082 ± 0.003 yr in the rest frame at the z = 1.285 redshift of PKS 2131−021. The periodic variation in PKS 2131−021 is remarkably sinusoidal. We present a model in which orbital motion, combined with the strong Doppler boosting of the approaching relativistic jet, produces a sine-wave modulation in the flux density that easily fits the observations. Given the rapidly developing field of gravitational-wave experiments with pulsar timing arrays, closer counterparts to PKS 2131−021 and searches using the techniques we have developed are strongly motivated. These results constitute a compelling demonstration that the phenomenology, not the theory, must provide the lead in this field.

Combined impacts of natural recruitment and active propagation for coral population recovery on the Great Barrier Reef

Coral populations on the Great Barrier Reef (GBR) are experiencing long-term shifts in size structure, including steep declines in small colonies, driving major concerns for recovery through the supply of new recruits. Whilst coral restoration began on the GBR in 2018, the combined influence of natural recruitment and outplanting for coral population recovery has not been evaluated. Here, we assessed 2 sites (Rayban and Mojo) at Opal Reef that were subject to intensive outplant efforts over a 3 yr period (2018-2021). Coral cover did not change significantly, with a baseline of 15% in 2018 and a cover of 28 and 25% in Rayban outplant and control areas, respectively, in 2021, while Mojo exhibited a coral cover of 38% in 2018 and 52% (outplant area) and 29% (control area) in 2021. Natural recruitment in 2021 did not vary by site and was characterised by a settlement rate of 5.5 and 3.7 recruits tile-1 at Rayban and Mojo, respectively. Juvenile coral abundance and diversity were similar for control and outplant areas at each site. Over the 3 yr period, coral cover as a metric did not identify differences between control and outplant areas; however, size-frequency distributions of key coral taxa revealed a higher frequency of small to mid-sized colonies in outplant communities compared to controls. Given that no differences were observed in recruitment rates or juvenile abundances, variations in population structure appear to be driven by planting efforts rather than natural recovery. Our results demonstrate the need for combined monitoring of natural versus intervention-based rehabilitation to understand the impact of coral propagation efforts for local site recovery.

Precocial male maturation contributes to the introgression of farmed Atlantic salmon into wild populations

The escape of domesticated Atlantic salmon Salmo salar from aquaculture facilities represents a continued threat to the genetic and demographic stability of wild salmon stocks. Escaped farm-origin salmon have been shown to hybridize with wild conspecifics, yet the long-term genetic impacts are generally unknown. Theoretically, life history variation, specifically precocial maturation of male hybrids, could fast-track introgression, but evidence for this has been sparse. Here, we used empirical and experimental data to examine the role of precocious male maturation in introgression. We examined hybrid class composition using juvenile sampling and genetic assignment over a 5 yr period following an escape event in southern Newfoundland, a region with high rates of natural male precocial maturation. Initially following the escape, the proportion of first-generation (F1) hybrids was high and then decreased annually, contrasting the proportion of backcross wild individuals, which increased over time. The presence and temporal distribution of backcross wild individuals supports the hypothesis that high rates of precocial maturation can fast-track the long-term impacts of escaped farmed salmon on wild populations via interbreeding. This was experimentally tested using lab-created wild, farmed, and F1 parr released and recaptured from a Newfoundland river to assess levels of precocious male maturation. Observed rates of maturation of F1 hybrids were high and similar to wild parr (77 vs. 73%, respectively), indicating that most F1 hybrids mature precocially. Our results suggest that rates of precocial male maturation should be explicitly considered in risk assessments evaluating the genetic impacts of escaped farmed salmon on wild populations.

Evaluation of red snapper Lutjanus campechanus trophic dynamics with simultaneous stomach content and stable isotope analysis

The importance of multiple prey taxa to red snapper Lutjanus campechanus diet was investigated using simultaneous stomach content analysis (SCA) and stable isotope analysis (SIA) over a 2 yr period in the north-central Gulf of Mexico (GOM) across 3 depth strata and 3 artificial structure types. Stable nitrogen isotope values were also used to estimate the trophic positions (TPs) of red snapper and prey items. SCA results showed that a variety of taxonomic prey groups were consumed, but the most frequent prey were stomatopods, portunid crabs and several families of fish. Some isotopic differences were found between red snapper size and age classes and across habitat types and depth strata for each sampling year; however, no consistent differences were found across the entire study period. Stable isotope mixing model results showed that diet varied annually, with sciaenid fishes being the greatest contributor in 2016 and portunid crabs in 2017, with the remaining proportions split across other taxa. Red snapper TP ranged from 3.4 to 4.8, while that of most prey groups was highly variable. The consistency in red snapper isotope values and the isotopic inconsistency of prey groups suggests that individual red snapper feed evenly across a taxonomically and isotopically diverse prey field. These results help develop a better understanding of reef ecology and food web structure in the northern GOM. Future investigations of red snapper diet that characterize reef habitats in terms of the available prey field and environmental conditions would improve our understanding of its trophic role in reef food webs.

High female desert tortoise mortality in the western Sonoran Desert during California’s epic 2012-2016 drought

We conducted population surveys for desert tortoisesGopherus agassiziiat 2 nearby sites in the western Sonoran Desert of California, USA, from 2015-2018, during the driest ongoing 22 yr period (2000-2021) in the southwestern USA in over 1200 yr. We hypothesized that drought-induced mortality would be female-biased due to water and energy losses attributable to egg production during protracted periods of resource limitation. At the higher-elevation, cooler, wetter Cottonwood site from 2015-2016, the sex ratio of live adult tortoises was biased toward males and the sex ratio of tortoises estimated to have died during the intensified drought conditions from 2012-2016 was essentially even. At the lower-elevation, warmer, drier Orocopia site from 2017-2018, the sex ratio of live adult tortoises was biased toward males and the sex ratio of tortoises with estimated times of death from 2012-2016 was biased toward females. High female mortality at the Orocopia site may have resulted from the interaction of drought effects and the bet-hedging reproductive strategy of tortoises wherein they continue to produce clutches of eggs in drought years. Annual reproductive output results in an estimated loss of up to 13.5% of female tortoise body mass including over 0.20 l of water. Combined with dehydration during severe droughts, these losses may compromise their ability to survive droughts lasting more than 2 yr. The low tortoise density and high mortality of females observed may reflect reduced survival of tortoises near the southern edge of their range due to climate change, including protracted and intensified droughts.

North American rain-on-snow ablation climatology

Rain-on-snow ablation events carry a relatively high risk for rapid snowmelt and runoff due to the combination of liquid precipitation and generally high turbulent fluxes into the snowpack. Determining the variability in rain-on-snow ablation is critical in describing local hydroclimate. This study uses a gridded observational snow dataset to examine spatiotemporal variations in North American rain-on-snow ablation over a 50 yr period. Here we show rain-on-snow ablation represents approximately 33% of all ablation events in the eastern third of the continent, compared to &lt;20% in its interior. Rain-on-snow ablation was most frequent along the western and eastern coasts of the continent, with &gt;10 events observed per year on average. A central band of enhanced event frequencies propagated meridionally during the calendar year, most prominently in the eastern half of the continent. Seasonal (September to August) event frequency from 1960-2009 significantly decreased by approximately 50% across much of northern Quebec and in the southern Appalachians, while it significantly increased in portions of British Columbia and southeastern Quebec. Interannual variations in event frequency were primarily forced by variations in seasonal-scale snowfall and snow depth, and only moderately associated with variations in air temperatures.

Distribution and prevalence of the myxozoan parasite Tetracapsuloides bryosalmonae in northernmost Europe: analysis of three salmonid species.

Global climate change is altering the abundance and spread of many aquatic parasites and pathogens. Proliferative kidney disease (PKD) of salmonids caused by the myxozoan Tetracapsuloides bryosalmonae is one such emerging disorder, and its impact is expected to increase with rising water temperature. Yet, the distribution and prevalence of T. bryosalmonae in Northern Europe remain poorly characterized. Here, we studied 43 locations in 27 rivers in northernmost Norway and Finland to describe T. bryosalmonae infection frequency and patterns in 1389 juvenile salmonids. T. bryosalmonae was discovered in 12 out of 27 rivers (44%) and prevalence ranged from 4.2 to 55.5% in Atlantic salmon and from 5.8 to 75% in brown trout among infected rivers. In sympatric populations, brown trout was more frequently infected with T. bryosalmonae than was salmon. Age-specific parasite prevalence patterns revealed that in contrast to lower latitudes, the infection of juvenile fish predominantly occurs during the second summer or later. Temperature monitoring over 2 yr indicated that the mean water temperature in June was 2.1 to 3.2°C higher in rivers containing T. bryosalmonae compared to parasite-free rivers, confirming the important role of temperature in parasite occurrence. Temporal comparison in T. bryosalmonae prevalence over a 10 yr period in 11 rivers did not reveal any signs of contemporary parasite spread to previously uninfected rivers. However, the wide distribution of T. bryosalmonae in rivers flowing to the Barents Sea indicates that climate change and heat waves may cause new disease outbreaks in northern regions.

Spatio-temporal trend and frequency analysis of precipitation in South-southern Nigeria (SSN)

Precipitation is one of the key climatic parameters that have a significant impact on the spatial and temporal trends of available water resources in a region. Therefore, carrying out a long-term analysis on its seasonal and annual trends and variability is imperative for viable water resources management. This study investigates the seasonal and annual precipitation data for South-southern Nigeria (SSN) between 1951 and 2016. Over the 66 yr period, SSN witnessed a region-wide decrease in annual and DJF, MAM and JJA seasonal precipitation; while in SON, precipitation was reduced in 81.2% of the stations. On the regional level, station-specific trend analysis confirmed a region-wide decrease; however, a greater number of significant declines were found for annual and MAM precipitation records for all 6 states within SSN. The degree of wetness and dryness within the states indicate that all experienced more periods of extreme dryness than extreme wetness during the study duration. This may be attributed to evident changes in climate that are also reflected in the decreasing trends reported for the annual and seasonal timescales. The only significant cycle was detected at 1 yr timescale throughout the study period for precipitation time series in all the six states in SSN.. The major results of this study show that SSN may have challenges in securing the water required for agriculture and other domestic needs if adequate measures are not in place to fully harness other water sources within the crop-growing season of MAM.

Influence of environmental and population factors on Prince William Sound herring spawning phenology

Shifts in spawning phenology may impact the early life stages of small pelagic fishes, affecting their first-year survival and recruitment. In Prince William Sound, Pacific herring is a key forage species that once supported commercial and subsistence fisheries for many decades, but collapsed in 1993 and has yet to recover. Starting in 1980, spawn timing shifted earlier by approximately 2-4 wk over a 27 yr period, then abruptly shifted later by approximately 3 wk over the next 7 yr. We quantified the influence of 15 environmental and population-level covariates on these spawn timing shifts using generalized linear models. Earlier spawn timing was associated with higher biomass in the eastern sound and older mean age in the western sound. Across the entire sound, earlier spawning was associated with weaker downwelling, weaker meridional winds, and the positive phase of the Pacific-North American teleconnection pattern, which is characterized by warmer North Pacific waters. These results are a critical first step towards assessing how changes in spawning phenology impact first-year survival of herring offspring and potentially contribute to persistent poor recruitment that has inhibited the recovery of the Prince William Sound population.

Insights into the trophic ecology of white-beaked dolphins Lagenorhynchus albirostris and harbour porpoises Phocoena phocoena in Iceland

Sympatric organisms can avoid competition by occupying different ecological niches, a mechanism known as niche partitioning. In Iceland, white-beaked dolphinsLagenorhynchus albirostrisand harbour porpoisesPhocoena phocoenaare the most common small cetaceans observed but their trophic ecology remains understudied, including the potential for resource competition. In this study, we measured δ15N and δ13C values from white-beaked dolphin (n = 28) and harbour porpoise (n = 29) muscle samples collected over a 33 yr period (1987-2019) to compare isotopic niche width and overlap of both species, as well as diet composition. We also tested for within-species effects of sex, age class, body length, year of sampling and origin (bycatch vs. stranding) on the δ13C and δ15N values. Intra-species variations included differences between stranded and bycaught white-beaked dolphins and ontogenetic variations in both species, but further studies are necessary to investigate the factors that might explain these results. Inter-species comparisons showed that harbour porpoises and white-beaked dolphins had non-overlapping isotopic niches, with harbour porpoises exhibiting smaller niche widths (corrected standard ellipse area, SEAc: 1.25 vs. 2.13‰2). While white-beaked dolphins had a broader diet, composed primarily of gadoids but with contributions of other fish species, harbour porpoises fed almost exclusively on capelinMallotus villosus, suggesting niche segregation and width is largely maintained by targeting different prey resources. Both species also showed no long-term changes in trophic ecology, despite recent ecosystem changes in this region, possibly a result of adapting to spatial changes in prey distribution or shifts to other prey at similar trophic levels.