Individual life histories: neither slow nor fast, just diverse

The slow-fast continuum is a commonly used framework to describe variation in life-history strategies across species. Individual life histories have also been assumed to follow a similar pattern, especially in the pace-of-life syndrome literature. However, whether a slow-fast continuum commonly explains life-history variation among individuals within a population remains unclear. Here, we formally tested for the presence of a slow-fast continuum of life histories both within populations and across species using detailed long-term individual-based demographic data for 17 bird and mammal species with markedly different life histories. We estimated adult lifespan, age at first reproduction, annual breeding frequency, and annual fecundity, and identified the main axes of life-history variation using principal component analyses. Across species, we retrieved the slow-fast continuum as the main axis of life-history variation. However, within populations, the patterns of individual life-history variation did not align with a slow-fast continuum in any species. Thus, a continuum ranking individuals from slow to fast living is unlikely to shape individual differences in life histories within populations. Rather, individual life-history variation is likely idiosyncratic across species, potentially because of processes such as stochasticity, density dependence, and individual differences in resource acquisition that affect species differently and generate non-generalizable patterns across species.

Current and lagged climate affects phenology across diverse taxonomic groups

The timing of life events (phenology) can be influenced by climate. Studies from around the world tell us that climate cues and species' responses can vary greatly. If variation in climate effects on phenology is strong within a single ecosystem, climate change could lead to ecological disruption, but detailed data from diverse taxa within a single ecosystem are rare. We collated first sighting and median activity within a high-elevation environment for plants, insects, birds, mammals and an amphibian across 45 years (1975-2020). We related 10 812 phenological events to climate data to determine the relative importance of climate effects on species' phenologies. We demonstrate significant variation in climate-phenology linkage across taxa in a single ecosystem. Both current and prior climate predicted changes in phenology. Taxa responded to some cues similarly, such as snowmelt date and spring temperatures; other cues affected phenology differently. For example, prior summer precipitation had no effect on most plants, delayed first activity of some insects, but advanced activity of the amphibian, some mammals, and birds. Comparing phenological responses of taxa at a single location, we find that important cues often differ among taxa, suggesting that changes to climate may disrupt synchrony of timing among taxa.

Temporal correlations among demographic parameters are ubiquitous but highly variable across species

Temporal correlations among demographic parameters can strongly influence population dynamics. Our empirical knowledge, however, is very limited regarding the direction and the magnitude of these correlations and how they vary among demographic parameters and species’ life histories. Here, we use long‐term demographic data from 15 bird and mammal species with contrasting pace of life to quantify correlation patterns among five key demographic parameters: juvenile and adult survival, reproductive probability, reproductive success and productivity. Correlations among demographic parameters were ubiquitous, more frequently positive than negative, but strongly differed across species. Correlations did not markedly change along the slow‐fast continuum of life histories, suggesting that they were more strongly driven by ecological than evolutionary factors. As positive temporal demographic correlations decrease the mean of the long‐run population growth rate, the common practice of ignoring temporal correlations in population models could lead to the underestimation of extinction risks in most species.

Maternal survival costs in an asocial mammal

Maternal characteristics, social dynamics, and environmental factors can all influence reproduction and survival and shape trade‐offs that might arise between these components of fitness. Short‐lived mammals like the golden‐mantled ground squirrel (GMGS; Callospermophilus lateralis) tend to maximize effort toward current reproduction at the expense of survival but may be complicated by other aspects of the species’ life history and environment. Here, we use 25 years of data (1995–2020) collected from a population of GMGS at the Rocky Mountain Biological Research Laboratory in Gothic, Colorado, to test the effect of several maternal characteristics (e.g., age, experience, and timing of litter emergence), social context (e.g., litter sex ratio and kin density), and environmental context (e.g., date of bare ground and length of vegetative growing season) on survival of reproductive female GMGS using Cox proportional hazard models. Our results indicated that social dynamics (i.e., density) and environmental conditions (i.e., standardized first day of permanent snow cover and length of growing season) explained significant variation in annual maternal survival, while maternal characteristics did not. A higher density of related breeding females and the total number of females (both related and unrelated to the focal mother) were associated with an increase in the mortality hazard. A later standardized date of the first day of permanent snow cover and a shorter growing season both reduced the maternal mortality hazard. Together, our results suggest that factors extrinsic to the squirrels affect maternal survival and thus may also influence local population growth and dynamics in GMGS and other short‐lived, territorial mammal species.

We used 25 years of longitudinal data collected from golden‐mantled ground squirrel females to test the effects of individual characteristics, the social context, and the environment on female mortality using Cox proportional hazard models. Both female kin density and the environmental context explained significant variation in female mortality, while individual characteristics did not. Our results suggest that both kin density and climate metrics related to growing season phenology swamp individual characteristics in explaining variability in maternal mortality. This is an important finding in a rather short‐lived species where every additional active season survived has a lot of weight in improving lifetime reproduction.

Expanding the landscape of opportunity: Professional societies support early-career researchers through community programming and peer coaching

Weaving the future of the field of comparative psychology is dependent on the career advancement of early-career scientists. Despite concerted efforts to increase diversity in science, technology, engineering, and mathematics, scholars from marginalized groups are disproportionately underrepresented in the field-especially at advanced career stages. New approaches to sponsorship, mentoring, and community building are necessary to retain talent from marginalized communities and to create a culture and a system where all individuals can thrive. We describe the unique and supportive role of senior women scientists united through a professional society in initiating peer coaching circles to facilitate the success of a diverse cohort of early-career women scientists. We offer our experiences with the Weaving the Future of Animal Behavior program as a case study that illustrates the cascading impacts of professional societies investing in the success and career development of marginalized scholars. We focus on our peer coaching circle experience and share the products and outcomes after 2 years of meeting. Peer coaching transformed us from a group of loosely organized, anxious individuals into a collective of empowered agents of change with an enhanced sense of belonging. We end by presenting recommendations to institutions seeking to expand the landscape of opportunities to other marginalized scholars. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Pedigree simulations reveal that maternity assignment is reliable in populations with conspecific brood parasitism, incomplete parental sampling and kin structure

Modern genetic parentage methods reveal that alternative reproductive strategies are common in both males and females. Under ideal conditions, genetic methods accurately connect the parents to offspring produced by extra-pair matings or conspecific brood parasitism. However, some breeding systems and sampling scenarios present significant complications for accurate parentage assignment. We used simulated genetic pedigrees to assess the reliability of parentage assignment for a series of challenging sampling regimes that reflect realistic conditions for many brood-parasitic birds: absence of genetic samples from sires, absence of samples from brood parasites and female kin-structured populations. Using 18 microsatellite markers and empirical allele frequencies from two populations of a conspecific brood parasite, the wood duck (Aix sponsa), we simulated brood parasitism and determined maternity using two widely used programs, cervus and colony. Errors in assignment were generally modest for most sampling scenarios but differed by program: cervus suffered from false assignment of parasitic offspring, whereas colony sometimes failed to assign offspring to their known mothers. Notably, colony was able to accurately infer unsampled parents. Reducing the number of markers (nine loci rather than 18) caused the assignment error to slightly worsen with colony but balloon with cervus. One potential error with important biological implications was rare in all cases-few nesting females were incorrectly excluded as the mother of their own offspring, an error that could falsely indicate brood parasitism. We consider the implications of our findings for both a retrospective assessment of previous studies and suggestions for best practices for future studies.

Abundance, density, and social structure of African forest elephants (Loxodonta cyclotis) in a human-modified landscape in southwestern Gabon

Population monitoring is critical to effective conservation, but forest living taxa can be difficult to directly observe. This has been true of African forest elephants (Loxodonta cyclotis), for which we have limited information regarding population size and social behavior despite their threatened conservation status. In this study, we estimated demographic parameters using genetic capture-recapture of forest elephants in the southern Industrial Corridor of the Gamba Complex of Protected Areas in southwestern Gabon, which is considered a global stronghold for forest elephants. Additionally, we examined social networks, predicting that we would find matrilineal structure seen in both savanna and forest elephants. Given 95% confidence intervals, we estimate population size in the sampled area to be between 754 and 1,502 individuals and our best density estimate ranges from 0.47 to 0.80 elephants per km². When extrapolated across the entire Industrial Corridor, this estimate suggests an elephant population size of 3,033 to 6,043 based on abundance or 1,684 to 2,832 based on density, approximately 40–80% smaller than previously suggested. Our social network analysis revealed approximately half of network components included females with different mitochondrial haplotypes suggesting a wider range of variation in forest elephant sociality than previously thought. This study emphasizes the threatened status of forest elephants and demonstrates the need to further refine baseline estimates of population size and knowledge on social behavior in this taxon, both of which will aid in determining how population dynamics in this keystone species may be changing through time in relation to increasing conservation threats.

Exploring phospholipase C-coupled Ca(2+) signalling networks using Boolean modelling

In this study, the authors explored the utility of a descriptive and predictive bionetwork model for phospholipase C-coupled calcium signalling pathways, built with non-kinetic experimental information. Boolean models generated from these data yield oscillatory activity patterns for both the endoplasmic reticulum resident inositol-1,4,5-trisphosphate receptor (IP(3)R) and the plasma-membrane resident canonical transient receptor potential channel 3 (TRPC3). These results are specific as randomisation of the Boolean operators ablates oscillatory pattern formation. Furthermore, knock-out simulations of the IP(3)R, TRPC3 and multiple other proteins recapitulate experimentally derived results. The potential of this approach can be observed by its ability to predict previously undescribed cellular phenotypes using in vitro experimental data. Indeed, our cellular analysis of the developmental and calcium-regulatory protein, DANGER1a, confirms the counter-intuitive predictions from our Boolean models in two highly relevant cellular models. Based on these results, the authors theorise that with sufficient legacy knowledge and/or computational biology predictions, Boolean networks can provide a robust method for predictive modelling of any biological system. [Includes supplementary material].

South Thames quality standard for nuclear medicine equipment. South Thames Region Nuclear Medicine Specialty Service Committee

A survey of the quality assurance of the nuclear medicine equipment in use in the South Thames Region was undertaken as part of the clinical audit process within the region. The results revealed the variation in practice across the region and highlighted the need for an agreed quality standard, together with the appropriate level of physics support to provide that standard.

South Thames Nuclear Medicine Survey 1996-97. South Thames Regional Nuclear Medicine Specialty Service Committee

Data on the equipment available, staffing levels, number and type of procedures carried out in the South Thames Region during 1993-94 and 1996-97 are presented. These are compared with national data for 1993. The number of gamma cameras has increased by 5%, overall staffing by 15% and the number of procedures has increased by 31%. There has been a disproportionate increase in the technically more complex procedures, for example cardiac tomography (84%). Regional data have been collated since 1979 and techniques have been established to ensure consistency. Staffing levels, although improving, do not meet the minimum levels recommended by professional bodies. This raises questions about the quality and, possibly, the legality of the service provision.

Radiation dose rates from patients receiving iodine-131 therapy for carcinoma of the thyroid

Patients treated with radioiodine present a radiation hazard and precautions are necessary to limit the radiation dose to family members, nursing staff and members of the public. The precautions advised are usually based on instantaneous dose rates or iodine retention and do not take into account the time spent in close proximity with a patient. We have combined whole-body dose rate measurements taken from 86 thyroid cancer patients after radioiodine administration with published data on nursing and social contact times to calculate the cumulative dose that may be received by an individual in contact with a patient. These dose estimates have been used to calculate restrictions to patients behaviour to limit received doses to less than 1 mSv. We have also measured urinary iodide excretion in 19 patients to estimate the potential risk from the discharge of radioiodide into the domestic drainage system. The dose rate decay was biexponential for patients receiving radioiodine to ablate the thyroid after surgery (the ablation group, A) and monoexponential for these receiving subsequent treatments for residual or recurrent disease (the follow-up group, FU). The faster clearance in the follow-up patients generally resulted in less stringent restrictions than those advised for ablation patients. For typical activities of 1850 MBq for the ablation patients and 3700 MBq or 7400 MBq for the follow-up patients, the following restrictions were advised. Patients could travel in a private car for up to 8h on the day of treatment (for an administered activity of 1850 MBq in group A) or 4 and 2h (for activities of 3700 or 7400 MBq in group FU) respectively. Patients should remain off work for 3 days (1850 MBq/group A) or 2 days (up to 7400 MBq/group FU). Partners should avoid close contact and sleep apart for 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq/group FU). Contact with children should be restricted according to their age, ranging from 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq in group FU) for younger children, down to 10 days (1850 MBq/group A) or 4 days (up to 7400 MBq/group FU) for older children. The cumulative dose to nursing staff for the week after treatment was dependent on patient mobility and was estimated at 0.08 mSv for a self-caring patient to 6.3 mSv for a totally helpless patient (1840 MBq/group A). Corresponding doses to nurses looking after patients in group FU were 0.18-12.3 mSv (3700 MBq) or 0.36-24.6 mSv (7400 MBq). Sensible guidelines can be derived to limit the dose received by members of the public and staff who may come into contact with cancer patient treated with radioiodine to less than 1 mSv. The rapid clearance of radioiodine in patients treated on one or more than one occasion means that therapy could be administered at home to selected patients with suitable domestic circumstances. In most cases the restriction times, despite the high administered activities, are less than those for patients treated for thyrotoxicosis. The concentration of radioiodide in domestic drainage systems should not pose a significant risk.

Home reporting for the nuclear clinician?

The computer-based 'home office' is becoming a widely accepted mode of operation for modern businesses. It is implausible to believe that a nuclear medicine department can be covered permanently at a distance by a single physician, but it should be possible to provide cover for colleagues during sickness or at night or weekends. We have used a 486 PC with a high-resolution screen and software provided by LINK Medical Ltd to obtain images from hospital sites using a modem link to ADAC, Bartec and Nuclear Diagnostic SUN workstations. The data were transferred via standard telephone lines to the homes of two of the authors. During a trial period lasting several months, 60 lung scans, 20 bone scans, 1 gastrointestinal bleeding study, 4 leukocyte scans, 5 bone tomograms, 9 renograms, 6 myocardial perfusion tomograms and 2 gated cardiac studies were transferred. The system allowed transfer of a 128 x 128 eight-view lung scan to be completed in approximately 2 min. The program on the PC allowed alteration of individual image contrast, image rotation, cine display and a variety of colour scales to enhance image interpretation. A system to transfer chest X-rays has been developed and typical transfer times are approximately 3.5 min. Within the viewing protocol on the PC, a reporting window was available with the ability to fax the report directly to the hospital. The system allowed consultants who live at a distance from their nuclear medicine departments to provide cover and is now used as an integral part of our out-of-hours service. The system also allows cover of satellite units or to provide cover for junior staff at night or weekends.

Gamma camera purchasing

The purchase of a new gamma camera is a major undertaking and represents a long-term commitment for most nuclear medicine departments. The purpose of tendering for gamma cameras is to assess the best match between the requirements of the clinical department and the equipment available and not necessarily to buy the 'best camera' [1-3]. After many years of drawing up tender specifications, this paper tries to outline some of the traps and pitfalls of this potentially perilous, although largely rewarding, exercise.

99Tcm sestamibi--a new agent for parathyroid imaging

Parathyroid imaging using 99Tcm sestamibi has been carried out prior to surgery in five patients with hyperparathyroidism and the results compared with a standard preoperative localization technique using 201Tl (thallous chloride). The 99Tcm sestamibi correctly localized all abnormal glands and showed higher parathyroid to thyroid uptake in three of four parathyroid adenomas. Both agents showed localization in a thyroid adenoma. The higher uptake of sestambi and better imaging properties of its 99Tcm radiolabel means that the agent may replace thallium for routine preoperative parathyroid localization.

99Tcm-MDP, 67Ga-citrate and 111In-leucocytes for detecting prosthetic hip infection

An assessment was made of the roles of 99Tcm-MDP, 67Ga-citrate and 111In-leucocytes in identifying infected hip prostheses. Fifty painful prosthetic hips were investigated with a 99Tcm-MDP bone scan and an 111In-labelled leucocyte scan (ILLS). In 32 cases, a 67Ga-citrate scan was also performed. Normal or focal MDP uptake was obtained only in uninfected hips. Diffuse uptake of MDP was obtained only in infected hips and in one case of non-septic synovitis which also produced a false positive ILLS. A focal MDP uptake superimposed on a diffuse pattern was obtained in both infected and uninfected hips. The ILLS was abnormal in eight out of 11 cases of infection and in two out of 39 cases without infection. The 67Ga scan was abnormal in five out of six cases of infection and in five out of 26 cases without infection. It was concluded that a 99Tcm bone scan should be performed first on a painful prosthetic hip, and that for detecting infection, an ILLS was more specific but less sensitive than a 67Ga-citrate scan.

Liver scintiscanning as a screening test in the detection of alcoholic cirrhosis

Ninety-nine patients with alcohol related problems underwent a liver scintiscan and biopsy. The scan changes were graded and compared with the histological changes found from percutaneous liver biopsy. The overall correlation between scan and biopsy changes was poor. However, scintiscanning was found to be highly sensitive (90%) in detecting cirrhosis and for this reason is useful as a screening test in selecting alcoholic patients for biopsy.

Leucocyte and contaminant cell-bound activities resulting from the labelling of leucocytes with 111In-oxine

A simple method is described for estimating the activities bound to leucocytes, erythrocytes, platelets and the free activity, as resulted from the preparation and labelling of leucocytes with 111In-oxine. Measurements are required only of 111In activity, suspension volumes, and platelet concentrations. The limitations of the method are discussed. When blood from a normal volunteer was labelled by an 111In-oxine manufacturer's recommended technique, the greatest proportion of activity was bound to leucocytes, and in addition, a significant proportion of the activity was found to be associated with platelets. If the number of centrifugations between sedimentation and labelling was reduced from two to one, the proportion of free activity increased at the expense of a reduction in leucocyte activity, but the platelet activity remained unchanged. The relative distribution of cell-bound and free activities was independent of the relative centrifugal force (85-450 g), and of the time (15-30 min) and the suspension volume (5-10 ml) used to incubate the cells with 111In-oxine.

A study of leucocyte labelling efficiencies obtained with 111In-oxine

The range of leucocyte labelling efficiencies with 111In-oxine for a group of patients extended significantly (P = 0.05) below that obtained for a series of labellings of the same normal blood from a volunteer. A retrospective analysis was made of the results in the two groups to identify the cause of this difference in range. The labelling efficiency for patients did not vary with the volume of 111In-oxine, and was independent of the whole blood leucocyte concentration. The difference between the average labelling efficiencies obtained for a group of patients and the normal series labelled by the same operator was more significant than the difference in average labelling efficiencies obtained by different operators. It was concluded that biological variation in patients' blood, rather than operator technique, must have been a more important cause to the difference in the labelling efficiency range between patients and normal. It was also concluded that variations of contaminant platelet-bound activity and of plasma viscosity were greater in the patient group than the normal series, and contributed to this difference in labelling efficiency range.

Is the skull view necessary in routine gamma camera bone scanning?

Bone scans were reviewed in 478 patients, 237 with carcinoma of the breast, 47 with carcinoma of the lung, 43 with carcinoma of the prostate, 56 with other malignancies and 95 in whom scans were performed for basic screening purposes. In only 11 of the scans reviewed were abnormalities of the skull alone observed and in only one of the 11 scans was the finding of an abnormality thought to be clinically useful. This study suggests that in patients with known malignant disease, the skull view adds little useful information. However, when performing bone scans for screening purposes, the skull view may well give helpful information.

Breast-milk radioactivity after a Tc-99m DTPA aerosol/Tc-99m MAA lung study

Measurements were made of the concentration of Tc-99m activity in samples of breast milk following an administration of Tc-99m DTPA aerosol for a lung ventilation image and one of Tc-99m MAA for lung perfusion. The activity was 222 nCi/ml of milk (8.2 kBq/ml) at 2 hr after the MAA injection, and it was found to be excreted exponentially with an effective half-life of 4.6 hr. There was a small incorporation of Tc-99m into breast-milk protein. We conclude that the combined use of these two Tc-99m agents did not indicate the interruption of breast feeding beyond 24 hr after administration of the MAA, and that for an aerosol ventilation study alone, breast feeding need not be interrupted for more than 4 hr after the test.

Potential radiation dose to a breast-fed infant following administration of sodium 32P-phosphate to the mother

A 32P uptake test to diagnose an intraocular tumour was performed on a lactating woman. Breast feeding of her infant had been stopped and after injection of the 32P, a sample of breast milk on two consecutive days was collected. The concentration of 32P in the milk was greater in the second sample than the first, but it was calculated that the potential whole body radiation dose to her infant on the second day would not have exceeded 180 microSv (18 mrem).

Dual radionuclide subtraction imaging of vertebral disc infection using an 111In-labelled leucocyte scan and a 99mTc-tin colloid scan

Interpretation of the posterior view of an 111In-labelled leucocyte scan is difficult when infection is suspected in that region of the spine overlaid by the left lobe of the liver. A case is reported of the successful localisation of infection in this region by combining an 111In-labelled leucocyte scan with a 99mTc-tin colloid scan in a dual radionuclide subtraction technique.

111In-labelled leucocyte and 99mTc-methylene diphosphonate bone scanning in pelvic osteomyelitis

A positive 99mTc-methylene diphosphonate bone scan was obtained in a case of pelvic osteomyelitis in a 15-year-old girl. An 111In-labelled leucocyte scan confirmed the presence of pus, gave a more accurate anatomical location than was obtained by the bone scan, and enabled the most suitable surgical route to be selected.

Location of parathyroid adenomas by 201Tl and 99mTc subtraction scanning

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Location of parathyroid adenomas by thallium-201 and technetium-99m subtraction scanning

Solitary parathyroid adenomas were correctly located before surgery in 20 out of 21 cases by using 201mT1 and 99mTc in a subtraction technique. The technique was not useful in identifying hyperplastic parathyroid glands. The technique is recommended as a useful procedure before surgery for primary hyperparathyroidism.