scholarly journals Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland

2021 ◽  
Vol 75 (8) ◽  
Author(s):  
Mònica Arso Civil ◽  
Emily Hague ◽  
Izzy Langley ◽  
Lindesay Scott-Hayward
Keyword(s):  
Additive Model ◽  
Model Framework ◽  
Generalised Additive Model ◽  
Photo Identification ◽  
Separation Time ◽  
Harbour Seals ◽  
Pup Survival ◽  
Lactating Females ◽  
Proximate Causes ◽  
Lactation Duration

AbstractFostering and allo-suckling are widespread among pinnipeds, and several hypotheses have been formulated to explain their occurrence. Here, we describe the occurrence of allo-suckling in harbour seals from photo-identification data of females and pups in Orkney (Scotland) during the pupping seasons between 2016 and 2019. We used a generalised linear model framework to investigate the effect of allo-suckling on the duration of lactation (females) and of nursing period (pups). A generalised additive model framework was used to explore how the probability of allo-suckling varied throughout the pupping season, and with changes in mother-pup separation time. Allo-suckling was observed in 31 females, at higher rates (18–37% of lactating females and 18–47% of the pups every year) than those observed in other phocid populations, with 13 females allo-suckling in multiple years. The duration of the pups’ nursing period was not affected by allo-suckling occurrence. However, females in mother-pup pairs where both mother and pup allo-suckled had longer lactation duration than when only the pup allo-suckled, or than in pairs where no allo-suckling was observed. The probability of allo-suckling increased during the pupping season and with increased mother-pup separation time. However, the proximate causes and the consequences on future reproductive output and pup survival remain unknown.Significance statementAllo-suckling, where females nurse others’ young, is widespread in pinnipeds, particularly among true seals. Given the high costs of lactation in pinnipeds, allo-suckling is a puzzling behaviour. Using photo-identification and field observations, we examined the occurrence of allo-suckling in harbour seals at a colony in Orkney, Scotland. We found that allo-suckling is common among seals at the study site, and at rates higher than reported elsewhere. Our results show that allo-suckling does not appear to affect the duration of the pups’ nursing period but does increase the lactation duration of females who suckle other pups and whose own pups also allo-suckle. This study highlights an area which requires further investigation as the energetic costs and benefits of allo-suckling remain poorly understood.

Growth performance of Acheta domesticus and Gryllus bimaculatus production reared under improvised cage system for increased returns and food security

2020 ◽  
pp. 1-10
Author(s):  
C.A. Ngonga ◽  
C.O. Gor ◽  
E.A. Okuto ◽  
M.A. Ayieko
Keyword(s):  
Relative Humidity ◽  
Growth Performance ◽  
Additive Model ◽  
Acheta Domesticus ◽  
Cotton Wool ◽  
Conventional System ◽  
Gryllus Bimaculatus ◽  
Generalised Additive Model ◽  
Cage System ◽  
Significant Difference

Cricket farming is emerging as a new venture in Kenya poised to help alleviate protein deficiency and improve household living standards. However, competing, limited and unaffordable rearing systems constrain productivity and optimisation of this new enterprise. This study sought to evaluate the growth performance of Acheta domesticus and Gryllus bimaculatus reared in improvised cage system to assess its technical effectiveness. Twenty-day old of both species of crickets were separately reared in improvised and conventional cage systems for comparison purposes. Whereas an improvised cage system is a set of structure devised using locally available materials especially where the standard materials are limited, a conventional cage system is a set of structure made of standard and ordinary materials. The improvised system comprised of bamboo hideouts, clean scrap blankets for drinking and laying, cut bamboo stem as drinking platter and the plywood-based cages while conventional system comprised of egg carton hideouts, cotton-wool for drinking and laying, plastic petri-dishes, and plastic buckets. Each group of crickets (100 live crickets) was daily provided with equal amount of feed and water. Average weekly temperature and relative humidity profiles were recorded using HOBO data loggers. Further, 49 live crickets per treatment were randomly sampled and weighed weekly. Generalised additive model and analysis of variance were adopted to model the data therefrom using R. The cage system had a significant effect on the growth performance of the crickets. The mean weight of the cricket species differed, but not the interaction with the cage system. Similarly, species, temperature and relative humidity also influenced the growth performance. Compared to the conventional system, improvised cage system showed better results in realising high cricket productivity though there was no significant difference in growth performance between the two systems. The focus therefore should be to evaluate the egg productivity in scrap blanket in relation to cotton wool and cost effectiveness in improvised system to inform future farm decisions.

scholarly journals The role of conidia in the dispersal of Ascochyta rabiei

2020 ◽  
Author(s):  
Ihsanul Khaliq ◽  
Joshua Fanning ◽  
Paul Melloy ◽  
Jean Galloway ◽  
Kevin Moore ◽  
...  
Keyword(s):  
Additive Model ◽  
Sprinkler Irrigation ◽  
Ascochyta Rabiei ◽  
Strong Wind ◽  
Generalised Additive Model ◽  
Rainfall Events ◽  
Plant Parts ◽  
Trap Plants ◽  
Further Development

AbstractAscochyta rabiei asexual spores (conidia) were assumed to spread over short distances (∼10 m) in a combination of rain and strong wind. The potential distance of conidial spread was investigated in three rainfall and three sprinkler irrigation events. Chickpea trap plants were distributed at the distances of 0, 10, 25, 50 and 75 m from infected chickpea plots before scheduled irrigation and forecast rainfall events. Trap plants were transferred to a controlled temperature room (20 °C) for 48 h (100% humidity) after being exposed in the field for 2–6 days for rainfall events, and for one day for irrigation events. After a 48 h incubation period, trap plants were transferred to a glasshouse (20 °C) to allow lesion development. Lesions on all plant parts were counted after two weeks, which gave an estimate of the number of conidia released and the distance travelled. Trap plants at all distances were infected in all sprinkler irrigation and rainfall events. The highest number of lesions on trap plants were recorded closest to the infected plots – the numbers decreased as the distance from the infected plots increased. There was a positive relationship between the amount of rainfall and the number of lesions recorded. A generalised additive model was developed that efficiently described spatial patterns of conidial spread. With further development, the model can be used to predict the spread of A. rabiei. This is the first systematic study to show that conidia distribute A. rabiei over longer distances than previously reported.

scholarly journals Acute effects of air pollution on ischaemic stroke onset and deaths: a time-series study in Changzhou, China

BMJ Open ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. e020425 ◽  
Author(s):  
Huibin Dong ◽  
Yongquan Yu ◽  
Shen Yao ◽  
Yan Lu ◽  
Zhiyong Chen ◽  
...  
Keyword(s):  
Time Series ◽  
Ischaemic Stroke ◽  
Statistical Significance ◽  
Additive Model ◽  
The Elderly ◽  
Acute Effect ◽  
Cold Season ◽  
Air Pollutant ◽  
Generalised Additive Model ◽  
Short Term Exposure

ObjectiveTo investigate the acute effect of air pollutants on ischaemic stroke (IS) and IS-related death.SettingFive urban districts in Changzhou, China, between 9 January 2015 and 31 December 2016.ParticipantsA total of 32 840 IS cases and 4028 IS deaths were enrolled.Main outcome measuresA time-series design, generalised additive model and multivariable regression model were used to examine the percentage change (95% CI) in daily IS counts and deaths with an IQR increase in air pollutant levels for different single or multiple lag days in single-pollutant and two-pollutant models.ResultsDaily IS counts increased 0.208% (95% CI 0.036% to 0.381%) with an IQR increment in the levels of nitrogen dioxide (NO2). The estimated risk of NO2was more robust in males and in the cold season. For daily IS counts, the estimated effects of NO2and sulfur dioxide (SO2) were more significant when adjusted for particulate matter with aerodynamic diameters <2.5 µm (PM2.5) and PM10. An IQR increment in the concentration of PM10, SO2and NO2significantly increased IS deaths with 6 days of cumulative effects (0.268%, 95% CI 0.007% to 1.528%; 0.34%, 0.088% to 0.592%; and 0.263%, 0.004% to 0.522%, respectively). Young individuals (<65 years old) had a higher IS mortality risk for PM2.5, PM10, NO2and CO. For IS death, the effect estimates of SO2in the elderly, females and the cold season were more pronounced; statistical significance was also identified for SO2when adjusted for carbon monoxide (CO).ConclusionsThis study suggested that short-term exposure to ambient NO2was associated with increased IS risk. In addition, SO2was associated with increased IS onset and death.

scholarly journals A generalised additive model to characterise dairy cows’ responses to heat stress – CORRIGENDUM

animal ◽  
2020 ◽  
Vol 14 (2) ◽  
pp. 425
Author(s):  
S. Benni ◽  
M. Pastell ◽  
F. Bonora ◽  
P. Tassinari ◽  
D. Torreggiani
Keyword(s):  
Heat Stress ◽  
Dairy Cows ◽  
Additive Model ◽  
Generalised Additive Model

scholarly journals Developing a novel hybrid model for the estimation of surface 8 h ozone (O<sub>3</sub>) across the remote Tibetan Plateau during 2005–2018

2020 ◽  
Vol 20 (10) ◽  
pp. 6159-6175 ◽  
Author(s):  
Rui Li ◽  
Yilong Zhao ◽  
Wenhui Zhou ◽  
Ya Meng ◽  
Ziyu Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Hybrid Model ◽  
Additive Model ◽  
World Health ◽  
The Tibetan Plateau ◽  
The Novel ◽  
Slow Increase ◽  
Potential Health ◽  
Generalised Additive Model ◽  
Northern Tibetan Plateau

Abstract. We developed a two-stage model called the random-forest–generalised additive model (RF–GAM), based on satellite data, meteorological factors, and other geographical covariates, to predict the surface 8 h O3 concentrations across the remote Tibetan Plateau. The 10-fold cross-validation result suggested that RF–GAM showed excellent performance, with the highest R2 value (0.76) and lowest root-mean-square error (RMSE) (14.41 µg m−3), compared with other seven machine-learning models. The predictive performance of RF–GAM showed significant seasonal discrepancy, with the highest R2 value observed in summer (0.74), followed by winter (0.69) and autumn (0.67), and the lowest one in spring (0.64). Additionally, the unlearning ground-observed O3 data collected from open-access websites were applied to test the transferring ability of the novel model and confirmed that the model was robust in predicting the surface 8 h O3 concentration during other periods (R2=0.67, RMSE = 25.68 µg m−3). RF–GAM was then used to predict the daily 8 h O3 level over the Tibetan Plateau during 2005–2018 for the first time. It was found that the estimated O3 concentration displayed a slow increase, from 64.74±8.30 µg m−3 to 66.45±8.67 µg m−3 from 2005 to 2015, whereas it decreased from the peak to 65.87±8.52 µg m−3 during 2015–2018. Besides this, the estimated 8 h O3 concentrations exhibited notable spatial variation, with the highest values in some cities of the northern Tibetan Plateau, such as Huangnan (73.48±4.53 µg m−3) and Hainan (72.24±5.34 µg m−3), followed by the cities in the central region, including Lhasa (65.99±7.24 µg m−3) and Shigatse (65.15±6.14 µg m−3), and the lowest O3 concentration occurred in a city of the southeastern Tibetan Plateau called Aba (55.17±12.77 µg m−3). Based on the 8 h O3 critical value (100 µg m−3) provided by the World Health Organization (WHO), we further estimated the annual mean nonattainment days over the Tibetan Plateau. It should be noted that most of the cities on the Tibetan Plateau had excellent air quality, while several cities (e.g. Huangnan, Haidong, and Guoluo) still suffered from more than 40 nonattainment days each year, which should be given more attention in order to alleviate local O3 pollution. The results shown herein confirm that the novel hybrid model improves the prediction accuracy and can be applied to assess the potential health risk, particularly in remote regions with few monitoring sites.

scholarly journals Estimating the impact of vaccination using age–time-dependent incidence rates of hepatitis B

2007 ◽  
Vol 136 (3) ◽  
pp. 341-351 ◽  
Author(s):  
N. HENS ◽  
M. AERTS ◽  
Z. SHKEDY ◽  
P. KUNG'U KIMANI ◽  
M. KOJOUHOROVA ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Generalized Additive Models ◽  
Additive Model ◽  
Penalized Regression ◽  
Incidence Rates ◽  
Additive Models ◽  
Time Dependent ◽  
Model Framework ◽  
Penalized Regression Splines ◽  
The Impact

SUMMARYThe objective of this study was to model the age–time-dependent incidence of hepatitis B while estimating the impact of vaccination. While stochastic models/time-series have been used before to model hepatitis B cases in the absence of knowledge on the number of susceptibles, this paper proposed using a method that fits into the generalized additive model framework. Generalized additive models with penalized regression splines are used to exploit the underlying continuity of both age and time in a flexible non-parametric way. Based on a unique case notification dataset, we have shown that the implemented immunization programme in Bulgaria resulted in a significant decrease in incidence for infants in their first year of life with 82% (79–84%). Moreover, we have shown that conditional on an assumed baseline susceptibility percentage, a smooth force-of-infection profile can be obtained from which two local maxima were observed at ages 9 and 24 years.

scholarly journals Epidemiology of dengue and the effect of seasonal climate variation on its dynamics: a spatio-temporal descriptive analysis in the Chao-Shan area on China’s southeastern coast

BMJ Open ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. e024197 ◽  
Author(s):  
Qin Zhang ◽  
Yuliang Chen ◽  
Yu Fu ◽  
Tao Liu ◽  
Qingying Zhang ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Temporal Dynamics ◽  
Descriptive Analysis ◽  
Additive Model ◽  
Climate Variation ◽  
Generalised Additive Model ◽  
Seasonal Climate ◽  
Southeastern Coast ◽  
Climatic Drivers ◽  
Spatio Temporal

ObjectiveDengue is a mosquito-transmitted virus infection that remains rampant across the tropical and subtropical areas worldwide. However, the spatial and temporal dynamics of dengue transmission are poorly understood in Chao-Shan area, one of the most densely populated regions on China’s southeastern coast, limiting disease control efforts. We aimed to characterise the epidemiology of dengue and assessed the effect of seasonal climate variation on its dynamics in the area.DesignA spatio-temporal descriptive analysis was performed in three cities including Shantou, Chaozhou and Jieyang in Chao-Shan area during the period of 2014–2017.SettingData of dengue cases of three cities including Shantou, Chaozhou and Jieyang in Chao-Shan area during 2014–2017 were extracted. Data for climatic variables including mean temperature, relative humidity and rainfall were also compiled.MethodologyThe epidemiology and dynamics of dengue were initially depicted, and then the temporal dynamics related to climatic drivers was assessed by a wavelet analysis method. Furthermore, a generalised additive model for location, scale and shape model was performed to study the relationship between seasonal dynamics of dengue and climatic drivers.ResultsAmong the cities, the number of notified dengue cases in Chaozhou was greatest, accounting for 78.3%. The median age for the notified cases was 43 years (IQR: 27.0–58.0 years). Two main regions located in Xixin and Chengxi streets of Chaozhou with a high risk of infection were observed, indicating that there was substantial spatial heterogeneity in intensity. We found an annual peak incidence occurred in autumn across the region, most markedly in 2015. This study reveals that periods of elevated temperatures can drive the occurrence of dengue epidemics across the region, and the risk of transmission is highest when the temperature is between 25°C and 28°C.ConclusionOur study contributes to a better understanding of dengue dynamics in Chao-Shan area.

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