Age‐specific fecundity of mammalian populations: A test of three mathematical models

The biotechnological potential for manipulating offspring sex in the rhinoceros and the elephant

Surveys are being conducted to monitor the reproductive health of elephants managed by the TAG/SSP. This study summarizes results of a 2005 survey and compares data to one conducted in 2002. Surveys were returned for 100% and 79.0% of Asian and African elephants, respectively. Of those, 79.3% of Asian and 92.1% of African elephants had weekly progestagen data to assess ovarian cyclicity. For Asian elephants, acyclicity rates were similar between the 2002 and 2005 surveys (13.3% versus 10.9%), whereas irregular cycling increased in 2005 (2.6% versus 7.6%), respectively. For African elephants, the percentages of both acyclicity (22.0% versus 31.2%) and irregular cycling females (5.2% versus 11.8%) increased. In both species, ovarian inactivity was more prevalent in the older age categories (>30 years of age), but for African elephants also occurred in the reproductive aged groups. Reproductive tract pathologies did not account for the majority of acyclicity problems. Several females changed cyclicity status between the two surveys, including from noncycling to cycling, suggesting this is not an irreversible condition. However, seven African females went from cycling to abnormal or no cyclic activity. In summary, the incidence of ovarian acyclicity in Asian elephants is low and stable, but appears to be increasing in African females. These findings reinforce the need for long-term reproductive monitoring programs and continuous reproductive surveys, even for females not being considered for breeding. With more data we hope to determine what factors are related to changes in ovarian status and how to reverse the trend towards acyclicity.

The evolutionary theory of senescence posits that as the probability of extrinsic mortality increases with age, selection should favour early-life over late-life reproduction. Studies on natural vertebrate populations show early reproduction may impair later-life performance, but the consequences for lifetime fitness have rarely been determined, and little is known of whether similar patterns apply to mammals which typically live for several decades. We used a longitudinal dataset on Asian elephants (Elephas maximus) to investigate associations between early-life reproduction and female age-specific survival, fecundity and offspring survival to independence, as well as lifetime breeding success (lifetime number of calves produced). Females showed low fecundity following sexual maturity, followed by a rapid increase to a peak at age 19 and a subsequent decline. High early life reproductive output (before the peak of performance) was positively associated with subsequent age-specific fecundity and offspring survival, but significantly impaired a female's own later-life survival. Despite the negative effects of early reproduction on late-life survival, early reproduction is under positive selection through a positive association with lifetime breeding success. Our results suggest a trade-off between early reproduction and later survival which is maintained by strong selection for high early fecundity, and thus support the prediction from life history theory that high investment in reproductive success in early life is favoured by selection through lifetime fitness despite costs to later-life survival. That maternal survival in elephants depends on previous reproductive investment also has implications for the success of (semi-)captive breeding programmes of this endangered species.

Mammoths

Many mathematical models for the disease transmission dynamics of Ebola have been developed and studied, particularly during and after the 2014 outbreak in West Africa. Most of these models are systems of ordinary differential equations (ODEs). One of the common assumptions made in these ODE models is that the duration of disease stages, such as latent and infectious periods, follows an exponential distribution. Gamma distributions have also been used in some of these models. It has been demonstrated that, when the models are used to evaluate disease control strategies such as quarantine or isolation, the models with exponential and Gamma distribution assumptions may generate contradictory results (Feng et al. in Bull Math Biol 69(5):1511-1536, 2007). Several Ebola models are considered in this paper with various stage distributions, including exponential, Gamma and arbitrary distributions. These models are used to evaluate control strategies such as isolation (or hospitalization) and timely burial and to identify potential discrepancies between the results from models with exponential and Gamma distributions.

Previous studies have concluded that wide variance in changes in insulin sensitivity markers following exercise training demonstrates heterogeneity in individual trainability. However, these studies frequently don’t account for technical, biological, and random within-subject measurement error. We used the standard deviation of individual responses (SDIR) to determine whether interindividual variability in trainability exists for fasting and postprandial insulin sensitivity outcomes following low-volume sprint interval training (SIT). We pooled data from 63 untrained participants who completed 6 weeks of SIT (n = 49; VO2max: 35 (7) mL⋅kg−1⋅min−1) or acted as no-intervention controls (n = 14; VO2max: 34 (6) mL⋅kg−1⋅min−1). Fasting and oral glucose tolerance test (OGTT)-derived measures of insulin sensitivity were measured pre- and post-intervention. SDIR values were positive and exceeded a small effect size threshold for changes in fasting glucose (SDIR = 0.27 [95%CI 0.07,0.38] mmol⋅L−1), 2-h OGTT glucose (SDIR = 0.89 [0.22,1.23] mmol⋅L−1), glucose area-under-the-curve (SDIR = 66.4 [−81.5,124.3] mmol⋅L−1⋅120min−1) and The Cederholm Index (SDIR = 7.2 [−16.0,19.0] mg⋅l2⋅mmol−1⋅mU−1⋅min−1), suggesting meaningful individual responses to SIT, whilst SDIR values were negative for fasting insulin, fasting insulin resistance and insulin AUC. For all variables, the 95% CIs were wide and/or crossed zero, highlighting uncertainty about the existence of true interindividual differences in exercise trainability. Only 2–22% of participants could be classified as responders or non-responders with more than 95% certainty. Our findings demonstrate it cannot be assumed that variation in changes in insulin sensitivity following SIT is attributable to inherent differences in trainability, and reiterate the importance of accounting for technical, biological, and random error when examining heterogeneity in health-related training adaptations. Highlights This study tested whether true interindividual variability exists for changes in insulin sensitivity and glyceamic control following 6-weeks of low volume sprint interval training (SIT). The high level of technical, biological, and random error associated with repeated measurements of insulin sensitivity and glycaemic control, means we can neither confidently conclude that there is evidence of true interindividual differences in the trainability of these outcomes following SIT, nor confidently identify responders or non-responders for such parameters. Researchers contrasting responders vs. non-responders for a given parameter, either to understand mechanisms of adaptation and/or develop physiological/genetic/epigenetic predictors of response, need to be aware that identification of responders and non-responders with sufficient certainty may not be achievable for parameters with a high level of technical, biological, and random error.

Delins, as known as complex indel, is a combined genomic structural variation formed by deleting and inserting DNA fragments at a common genomic location. Recent studies emphasized the importance of delins in cancer diagnosis and treatment. Although the long reads from PacBio CLR sequencing significantly facilitate delins calling, the existing approaches still encounter computational challenges from the high level of sequencing errors, and often introduce errors in genotyping and phasing delins. In this paper, we propose an efficient algorithmic pipeline, named delInsCaller, to identify delins on haplotype resolution from the PacBio CLR sequencing data. delInsCaller design a fault-tolerant method by calculating a variation density score, which helps to locate the candidate mutational regions under a high-level of sequencing errors. It adopts a base association-based contig splicing method, which facilitates contig splicing in the presence of false-positive interference. We conducted a series of experiments on simulated datasets, and the results showed that delInsCaller outperformed several state-of-the-art approaches, e.g., SVseq3, across a wide range of parameter settings, such as read depth, sequencing error rates, etc. delInsCaller often obtained higher f-measures than other approaches; specifically, it was able to maintain advantages at ~15% sequencing errors. delInsCaller was able to significantly improve the N50 values with almost no loss of haplotype accuracy compared with the existing approach as well.

The Living Elephants is the authoritative resource for information on both Asian and African elephants. From the ancient origins of the proboscideans to the present-day crisis of the living elephants, this volume synthesizes the behavior, ecology and conservation of elephants, while covering also the history of human interactions with elephants, all within the theoretical framework of evolutionary biology. The book begins with a survey of the 60-million year evolutionary history of the proboscideans emphasizing the role of climate and vegetation change in giving rise to a bewildering array of species, but also discussing the possible role of humans in the late Pleistocene extinction of mastodonts and mammoths. The latest information on the molecular genetics of African and Asian elephants and its taxonomic implications are then presented. The rise of the elephant culture in Asia, and its early demise in Africa are traced along with an original interpretation of this unique animal-human relationship. The book then moves on to the social life of elephants as it relates to reproductive strategies of males and females, development of behavior in young, communication, ranging patterns, and societal organization. The foraging strategies of elephants, their impact on the vegetation and landscape are then discussed. The dynamics of elephant populations in relation to hunting for ivory and their population viability are described with the aid of mathematical models. A detailed account of elephant-human interactions includes a treatment of crop depredation by elephants in relation to their natural ecology, manslaughter by elephants, habitat manipulation by humans, and a history of the ivory trade and poaching in the two continents. The ecological information is brought together in the final chapter to formulate a set of pragmatic recommendations for the long-term conservation of elephants. The broadest treatment of the subject yet undertaken, by one of the leading workers in the field, Raman Sukumar, the book promises to bring the understanding of elephants to a new level. It should be of interest not only to biologists but also a broader audience including field ecologists, wildlife administrators, historians, conservationists and all those interested in elephants and their future.

Dental microwear variation in complete molars of Loxodonta africana and Elephas maximus

Head muscles of Loxodonta africana and Elephas maximus with comments on Mammuthus primigenius muscles

The use of elephant ivory as a commodity is a factor in declining elephant populations. Despite recent worldwide elephant ivory trade bans, mammoth ivory trade remains unregulated. This complicates law enforcement efforts, as distinguishing between ivory from extant and extinct species requires costly, destructive and time consuming methods. Elephant and mammoth ivory mainly consists of dentine, a mineralized connective tissue that contains an organic collagenous component and an inorganic component of calcium phosphate minerals, similar in structure to hydroxyapatite crystals. Raman spectroscopy is a non-invasive laser-based technique that has previously been used for the study of bone and mineral chemistry. Ivory and bone have similar biochemical properties, making Raman spectroscopy a promising method for species identification based on ivory. This study aimed to test the hypothesis that it is possible to identify differences in the chemistry of mammoth and elephant ivory using Raman spectroscopy. Mammoth and elephant tusks were obtained from the Natural History Museum in London, UK. Included in this study were eight samples of ivory from Mammuthus primigenius, two samples of carved ivory bangles from Africa (Loxodonta species), and one cross section of a tusk from Elephas maximus. The ivory was scanned using an inVia Raman micro spectrometer equipped with a x50 objective lens and a 785nm laser. Spectra were acquired using line maps and individual spectral points were acquired randomly or at points of interest on all samples. The data was then analysed using principal component analysis (PCA) with use of an in-house MATLAB script. Univariate analysis of peak intensity ratios of phosphate to amide I and III peaks, and carbonate to phosphate peaks showed statistical differences (p<0.0001) in the average peak intensity ratios between Mammuthus primigenius, Loxodonta spp. and Elephas maximus. Full width at half maximum hight (FWHM)analysis of the phosphate peak demonstrated higher crystal maturity of Mammuthus primigenius compared to living elephant species. The results of the study have established that spectra acquired by Raman spectroscopy can be separated into distinct classes through PCA. In conclusion, this study has shown that well-preserved mammoth and elephant ivory has the potential to be characterized using Raman spectroscopy, providing a promising method for species identification. The results of this study will be valuable in developing quick and non-destructive methods for the identification of ivory, which will have direct applications in archaeology and the regulation of international trade.

Motion analysis technology is used in various settings to assess human kinematics. Assessing human movement underwater presents many challenges, making it important to understand measurement error associated with the setup and calibration of the system ensuring accuracy in resulting kinematics. This study assessed the accuracy across the entire domain of a submerged motion capture methodology. Six Qualisys cameras created an underwater capture volume of 6.9 × 2.1 × 2.1 m3. Average error levels were acceptable in four uncertainty trials (< ± 5 mm error). By selecting an area of interest that excluded areas with low accuracy near domain borders, measurement error reduced by up to 0.13 mm, up to 1.27 mm lower than outside this area. Interpolated error indicated that intracyclic measurement error may alter measured kinematics by up to 13.80 mm, with error greater than 5 mm affecting over 50% of the kick cycle. Investigating error levels across the domain can inform researchers whether a recalibration is necessary or help to identify areas where high error levels would affect kinematics. This study highlights the need to investigate error levels across a motion capture domain, particularly when this is a large volume, to ensure results obtained from investigations are reliable.

We explore when group interactions will have a positive effect on the accuracy of quantitative judgments. The results from two laboratory experiments revealed that the value of group interactions, compared to a statistical aggregation of individual judgments, depends strongly on how a group is structured, and that this effect is moderated by the level of systematic error among group members. In particular, when there was a low level of systematic error, group interactions generally provided little value and group structure did not have a significant effect on the value of group interactions. However, when the level of systematic error was high, the value of interactions in groups with a designated group leader was strongly positive and significantly higher than in consensus groups where interactions still provided only little value. Moreover, our analysis showed that this effect was mediated by information elaboration—which was generally higher in leader groups but only had a significant effect on the value of group interactions when there was a high level of systematic error among group members, and not otherwise. Consistent with these findings, we also found that when the level of systematic error was high, leader groups made more judgments that were outside of the range of initial individual judgments than consensus groups. Furthermore, members of leader groups in general spent more time discussing their task, and reported a higher motivation to process information systematically.

Error analysis is considered as a significant part in second and foreign language teaching. It helps teachers in understanding the better approaches for instructing by giving the input on the errors produced by students because students can learn from their errors. This study aimed at analyzing the errors produced by students in using do/does, have/has, and had. The methodology employed in this study was qualitative design. The population in this study was 149 students from all study programs. During the data collection, random sampling was utilized and there were 19 female students and 19 male students involved as the sample of this study. The instrument of this study was the instrument of this research adapted from Harald (2011). Later, the data were analyzed using Taxonomic Analysis. The result of the test showed that from the 38 students as the sample, 12 students were in high level of error, 8 students were in the level of fair, and 18 students were considered in the low level of error. These errors are assumed due to the interference of students’ first language structure to English. DOI: 10.26905/enjourme.v7i1.6684

There is evidence that low doses of convulsant agents may enhance acquisition under various behavioral procedures. The following experiments were undertaken to establish whether the putative GABA(A) antagonist pentylenetetrazole, and known GABA(A) receptor antagonists picrotoxin, picrotoxinin and bicuculine, might also enhance acquisition. Learning was studied under two different schedules of food presentation using the technique of repeated acquisition. Under this procedure, subject were required to acquire a different three-response sequence each session. Sequence completions were reinforced under a fixed-ratio five (FR 5) schedule, which engendered a low level of errors. A chain strained-ratio schedule was also studied because it engendered a high level of errors. Pentylenetetrazole (PTZ) (0.32-32mg/kg) generally produced a dose-related decrease in responding at higher doses (10-32mg/kg), while at lower doses (0.32-5.6mg/kg) response rate was not affected. PTZ generally disrupted accuracy of responding only at doses that decreased the rate of responding. Like PTZ, the noncompetitive GABA(A) receptor antagonist picrotoxin decreased the overall rate of responding and disrupted accuracy only at the higher doses tested (0.13-0.32mg/kg) in three of four subjects. At low doses (0.0032-0.1mg/kg), response rates and accuracy were unaffected when compared to the control ranges. Picrotoxinin, an active metabolite of picrotoxin, increased errors at doses that decreased the overall rate of responding. Conversely, the competitive GABA(A) receptor antagonist bicuculline (0.0032-0.56mg/kg) had no effect on accuracy and only decreased the rate of responding at doses that produced convulsions. Under the chain strained-ratio schedule, PTZ and picrotoxinin failed to enhance acquisition. These data suggest that pentylenetetrazole, picrotoxin, picrotoxinin and bicuculline do not reliably enhance acquisition in the squirrel monkey, and that differences exist between competitive and noncompetitive GABA(A) antagonists with regard to their effects on acquisition processes in the squirrel monkey. d-amphetamine, on the other hand, disrupted acquisition under the fixed-ratio schedule while at certain doses it enhanced acquisition under the strained-ratio schedule. The data also suggest that classical brain stem and cortical stimulants differ in terms of their ability to enhance acquisition under a strained-ratio schedule and that these differences may relate to their effects on conditioned reinforcement.