In late summer, sometime between cal a.d. 340–405, a hoard of tightly packed, stacked copper-alloy vessels was deposited in the Vale of Pewsey, Wiltshire. The corrosion of the vessels allowed for the preservation of delicate plant macrofossils and pollen. Analysis of this material has provided insights into the date, season and context of this act of structured deposition. A second hoard of similar vessels was deposited in the fourth or fifth century only a few miles away at Wilcot. The hoards and their deposition relate to Romano-British lifeways, at a time when the region was on the cusp of a dramatic period of change. The distribution of late Roman coins and belt fittings offers further insights into the social and economic character of Wiltshire at their times of deposition.

Heat stress due to increasing extremes in ambient temperature and humidity results in reduced semen quality in boars. This has caused reduced efficiency of the swine industry, requiring more boars to breed the same number of sows. Vitamins such as vitamin C (VC) and E (VE) have been shown to improve semen quality in boars. Recently, vitamin D has been shown to improve semen quality in boars. The purpose of this experiment was to evaluate the effects of increased supplemental vitamins on boar reproduction during the summer season in a commercial boar stud. One hundred and sixty Pig Improvement Company (PIC) terminal line boars (n = 32 per treatment) and 39 maternal, heat-sensitive boars (n = 7 or 8 per treatment) were randomly allocated to treatment and fed a corn and soybean meal-based diet adjusted based on individual boar body condition score. A control (CNT) diet was used that met PIC recommendations for boars. Increased supplementation of specific vitamins was given in the form of a top-dress and consisted of CNT wheat middlings, CNT plus VC (560 mg/day), CNT plus 25-hydroxy vitamin D3 (VD) (125 µg/day), CNT plus VE (275 mg/day) and CNT plus VC, VD and VE (CDE). The experiment was split into three periods based on maximum daily high temperatures in the barn, where period 1 was weeks 1 to 4, period 2 was weeks 5 to 11 and period 3 was weeks 12 to 14. Semen was collected from boars as needed using the stud’s normal production schedule and was analyzed for sperm quantity and quality characteristics. There were no dietary effects on semen volume, sperm concentration or total sperm production (P ≥ 0.553). Total motility of sperm was not impacted by diet (P = 0.115); although, VC tended (P = 0.064) to have a greater progressive motility than CDE. Percentages of morphologically normal sperm and normal acrosomes were not affected by dietary supplementation (P ≥ 0.157). Period effects were observed for most semen quality parameters, with quality generally becoming reduced over time. The present study demonstrates that increased supplementation of vitamins beyond PIC recommendations was not beneficial for boar reproduction during the summer.

Seasonal reproduction patterns are typically observed in small ruminants and are a major limitation for production efficiency in most meat- and dairy-type production systems. Indeed, selection for reduced seasonality could be an appealing strategy for the small ruminant industry worldwide, although its genetic background has been poorly analyzed. One of the main limitations relied on the availability of appropriate analytical tools to cope with the circular (i.e. year-round) pattern of lambing and kidding data. The recent development of a heteroskedastic circular mixed model provided the statistical tool to go deeply into the knowledge of seasonality in small ruminants. In this study, 26 005 lambing distribution records from 4764 Ripollesa ewes collected in 20 purebred flocks were analyzed. The model accounted for systematic (lambing interval and ewe age), permanent environmental (flock-year-season and ewe) and additive genetic sources of variation influencing both mean and dispersion pattern (i.e. heteroskedasticity). Systematic effects suggested that first-lambing ewes and short lambing intervals delayed lambing date (~30 days) and increased dispersion of the lambing period. Nevertheless, this was partially compensated by ewe age, given that youngest females tended to concentrate the lambing peak. Flock-year-season, permanent ewe and additive genetic sources of variation reached moderate variance components for direct (and residual) effects on lambing distribution, they being 0.119 (0.156), 0.092 (0.132) and 0.195 (0.170) radians2, respectively. Moreover, all 95% credibility intervals were placed far from the null estimate. Covariances between direct and residual effects where high and positive for additive genetic (posterior mean, 0.814) and permanent ewe effects (posterior mean, 0.917), whereas it was not relevant for flock-year-season. Selection for direct additive genetic effects should be able to advance or delay the lambing peak, whereas selection applied on residual additive genetic effects should increase or reduce seasonality (i.e. concentrate or flatten the lambing peak). Moreover, the positive and relevant genetic covariance between direct and residual effects also suggested correlated genetic responses. As example, genetic selection for earlier lambing peaks must also reduce seasonality, whereas selection for narrower lambing seasons may originate a delay in the lambing peak. These results must be viewed as the first attempt to analyze systematic, environmental and genetic sources of variation of lambing distribution within the circular paradigm, they providing a reliable characterization of these effects within the context of an heteroskedastic model.

The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.

The present work expands the existing knowledge on M. mola ecology by assessing, for the first time, its abundance (and body size distribution) in the southern waters of Portugal and relating the associated temporal variations with environmental variables. There were significant seasonal differences in abundance, with peaks in spring and autumn and lower values throughout the summer. Ocean sunfish abundance was positively correlated with sea surface temperature and chlorophyll a, indicating that a combination of both temperature and productivity dictates spatial use. Complementarily, the absence of a relationship between abundance and water transparency may reveal a strategy in spatial use favouring a medium-term steady food supply over short-term improved feeding opportunities. Specimens ranged between 31.8 and 230.0 cm (total length), with 98% of all individuals measuring between 31.8 and 59.9 cm. As the vast majority of specimens analysed were immature, seasonal differences in abundance should not be related to spawning.

The southern Cape of South Africa is important to understanding regional climate because it straddles the transition between the winter and summer rainfall zones. We examine late Quaternary changes in rainfall seasonality and aridity through analysis of micromammal assemblages from three sites: Boomplaas Cave and Nelson Bay Cave in the aseasonal rainfall zone and Byneskranskop 1 in the winter rainfall zone. Our interpretation is based on analysis of 123 modern micromammal assemblages accumulated by barn owls (Tyto alba), which empirically links species composition to climate. The Pleistocene record (∼65 to 12 ka) from Boomplaas Cave, together with the last glacial maximum (LGM) samples from Nelson Bay Cave, indicates enhanced winter rainfall, especially during the LGM. Boomplaas Cave documents progressive aridification from the LGM to the earliest Holocene, followed by a return to moderately humid conditions through the Holocene. Byneskranskop 1 indicates a dominance of winter rains over the last 17 ka and a shift from an arid middle Holocene to a humid later Holocene. Agreement between the micromammal record and other local and regional proxies reinforces the potential of southern African micromammal assemblages as paleoclimate indicators.

It has been reported that foetal death follows a seasonal pattern. Influenza virus infection has been postulated as one possible contributor to this seasonal variation. This ecological study explored the temporal association between the influenza activity and the frequency of foetal death. Time series analysis was conducted using weekly influenza-like illness consultation proportions from the Danish sentinel surveillance system and weekly proportions of spontaneous abortions and stillbirths from hospital registers from 1994 to 2009. The association was examined in an autoregressive (AR) integrated (I) moving average (MA) model and subsequently analysed with cross-correlation functions. Our findings confirmed the well-known seasonality in influenza, but also seasonality in spontaneous abortion. No clear pattern of seasonality was found for stillbirths, although the analysis exposed dependency between observations. One final AR integrated MA model was identified for the influenza-like illness (ILI) series. We found no statistically significant relationship between weekly influenza-like illness consultation proportions and weekly spontaneous abortion proportions (five lags: P = 0.52; 11 lags: P = 0.91) or weekly stillbirths (five lags: P = 0.93; 11 lags: P = 0.40). Exposure to circulating influenza during pregnancy was not associated with rates of spontaneous abortions or stillbirths. Seasonal variations in spontaneous abortion were confirmed and this phenomenon needs further investigation.

Perhaps the world's best-known cetacean, the bottlenose dolphin shows considerable variation in behaviour between and within populations in relation to differences in natural and anthropogenic conditions. Drivers of behavioural variation need to be identified to understand the dynamics of wild dolphin populations. Little research has been published on the bottlenose dolphin population found in the Southern Adriatic Sea. Using a set of spatial, temporal and social predictors, we aimed to investigate what variables are related to the behaviour of an under-studied population of bottlenose dolphins along the coastline of Montenegro. We present the results of a year-long study monitoring the behaviour of bottlenose dolphins along coastal Montenegro. We considered the effect of topography, seasonality and group size. A large proportion of travelling (55%) small groups (mean 4, range 1–9) in shallow waters (<50 m) was observed. We showed that seasonality alone explained behaviour best, with surface-feeding and socializing-resting increasing in autumn and winter. Group size was found to be a result of behavioural choice. We suggest seasonal changes in environmental conditions and anthropogenic pressure may explain the recorded behavioural pattern. This research points to the necessity of increased collaboration in the region to help understand complex patterns in behaviour and habitat use of local dolphin populations if effective conservation measures are to be developed.

Recent greening of vegetation across the Arctic is associated with warming temperatures, hydrologic change and shorter snow-covered periods. Here we investigated trends for a subset of arctic vegetation on the island of Greenland. Vegetation in Greenland is unique due to its close proximity to the Greenland Ice Sheet and its proportionally large connection to the Greenlandic population through the hunting of grazing animals. The aim of this study was to determine whether or not longer snow-free periods (SFPs) were causing Greenlandic vegetation to dry out and become less productive. If vegetation was drying out, a subsequent aim of the study was to determine how widespread the drying was across Greenland. We utilized a 15-year time-series obtained by the MODerate Resolution Imaging Spectroradiometer (MODIS) to analyze the Greenland vegetation by deriving descriptors corresponding with the SFP, the number of cumulative growing degree-days and the time-integrated Normalized Difference Vegetation Index. While the productivity of most vegetated areas increased in response to longer growing periods, there were localized regions that exhibited signs consistent with the drying hypothesis. In these areas, vegetation productivity decreased in response to longer SFPs and more accumulated growing degree-days.

Middle East respiratory syndrome coronavirus (MERS-CoV) remains a notable disease and poses a significant threat to global public health. The Arabian Peninsula is considered a major global epicentre for the disease and the virus has crossed regional and continental boundaries since 2012. In this study, we focused on exploring the temporal dynamics of MERS-CoV in human populations in the Arabian Peninsula between 2012 and 2017, using publicly available data on case counts and combining two analytical methods. Disease progression was assessed by quantifying the time-dependent reproductive number (TD-Rs), while case series temporal pattern was modelled using the AutoRegressive Integrated Moving Average (ARIMA). We accounted for geographical variability between three major affected regions in Saudi Arabia including Eastern Province, Riyadh and Makkah. In Saudi Arabia, the epidemic size was large with TD-Rs >1, indicating significant spread until 2017. In both Makkah and Riyadh regions, the epidemic progression reached its peak in April 2014 (TD-Rs > 7), during the highest incidence period of MERS-CoV cases. In Eastern Province, one unique super-spreading event (TD-R > 10) was identified in May 2013, which comprised of the most notable cases of human-to-human transmission. Best-fitting ARIMA model inferred statistically significant biannual seasonality in Riyadh region, a region characterised by heavy seasonal camel-related activities. However, no statistical evidence of seasonality was identified in Eastern Province and Makkah. Instead, both areas were marked by an endemic pattern of cases with sporadic outbreaks. Our study suggested new insights into the epidemiology of the virus, including inferences about epidemic progression and evidence for seasonality. Despite the inherent limitations of the available data, our conclusions provide further guidance to currently implement risk-based surveillance in high-risk populations and, subsequently, improve related interventions strategies against the epidemic at country and regional levels.

Large changes in landscape, vegetation, and culture in northwestern (NW) Europe during the first millennium AD seem concurrent with climatic shifts. Understanding of this relation requires high-resolution palaeoclimate reconstructions. Therefore, we compiled available climate reconstructions from sites across NW Europe (extent research area: 10°W–20°E, 45°–60°N) through review of literature and the underlying data, to identify supraregional climatic changes in this region. All reconstructions cover the period from AD 1 to 1000 and have a temporal resolution of ≤50 yr. This resulted in 22 climate reconstructions/proxy records based on different palaeoclimate archives: chironomids (1), pollen (6), Sphagnum mosses (1), stalagmites (8), testate amoebae (4), and tree rings (2). Comparing all temperature reconstructions, we conclude that summer temperatures between AD 1 and 250 were relatively high, and the period between AD 250 and 700 was characterised by colder summer conditions. The period from AD 700 to 1000 was again characterised by warmer summers. These temperature shifts occurred in the whole of NW Europe. In contrast, the compilation of precipitation reconstructions does not show a common pattern across NW Europe either as a result of a heterogeneous precipitation pattern or the lack of suitable and consistent precipitation proxies.

The pathophysiological mechanisms underlying the seasonal dynamic and epidemic occurrence of bacterial meningitis in the African meningitis belt remain unknown. Regular seasonality (seasonal hyperendemicity) is observed for both meningococcal and pneumococcal meningitis and understanding this is critical for better prevention and modelling. The two principal hypotheses for hyperendemicity during the dry season imply (1) an increased risk of invasive disease given asymptomatic carriage of meningococci and pneumococci; or (2) an increased transmission of these bacteria from carriers and ill individuals. In this study, we formulated three compartmental deterministic models of seasonal hyperendemicity, featuring one (model1-‘inv’ or model2-‘transm’), or a combination (model3-‘inv-transm’) of the two hypotheses. We parameterised the models based on current knowledge on meningococcal and pneumococcal biology and pathophysiology. We compared the three models' performance in reproducing weekly incidences of suspected cases of acute bacterial meningitis reported by health centres in Burkina Faso during 2004–2010, through the meningitis surveillance system. The three models performed well (coefficient of determination R2, 0.72, 0.86 and 0.87, respectively). Model2-‘transm’ and model3-‘inv-transm’ better captured the amplitude of the seasonal incidence. However, model2-‘transm’ required a higher constant invasion rate for a similar average baseline transmission rate. The results suggest that a combination of seasonal changes of the risk of invasive disease and carriage transmission is involved in the hyperendemic seasonality of bacterial meningitis in the African meningitis belt. Consequently, both interventions reducing the risk of nasopharyngeal invasion and the bacteria transmission, especially during the dry season are believed to be needed to limit the recurrent seasonality of bacterial meningitis in the meningitis belt.

According to the Centers for Disease Control and Prevention (CDC), from 2000 to 2014, reported cases of legionellosis per 100 000 population increased by 300% in the USA, although reports on disease seasonality are inconsistent. Using two national databases, we assessed seasonal patterns of legionellosis in the USA. We created a monthly time series from 1993 to 2015 of reported cases of legionellosis from the CDC, and from 1997 to 2006 of medical claims of legionellosis-related hospitalisation in older adults from the Centers for Medicaid and Medicare Services (CMS). We split the study time interval into two segments (before and after 2003), and applied a Poisson harmonic regression model to each dataset and each segment. The time series of monthly counts exhibited a significant shift of seasonal peaks from mid-September (9.676 ± 0.164 months) before 2003 to mid-August (8.452 ± 0.042 months) after 2003, along with an alarming increase in the amplitude of seasonal peaks in both CDC and CMS data. The lowest monthly reported cases of legionellosis in 2015 (281) exceed the maximum value reported before 2003 (206). We also observed a discrepancy between CDC and CMS data, suggesting that not all cases of legionellosis diagnosed by hospital-based laboratories were reported to the CDC. Improved reporting of legionellosis is required to better inform the public and organise disease prevention.

To examine the implications of seasonality for the construction of a single-year calibration curve we obtained separate dates on earlywood and latewood fractions of tree rings originating from England and dendrochronologically dated between AD 1352 and AD 1442. These demonstrated that an average difference of 26±15 yr exists between earlywood and latewood and that this difference can be as high as 33±19 yr during periods of high radiocarbon (14C) production. It is argued that this difference is due to both changes in atmospheric 14C and the incorporation of stored carbohydrates into earlywood. Based on this, it was possible to separate an atmospheric and physiological contribution to this difference. Our modeling indicates that storage can produce a difference of up to 10 years between earlywood and latewood. This suggests that full-year tree rings from deciduous trees may be less appropriate for the construction of a single-year calibration curve and that specific atmospheric events can be more easily detected by measuring only latewood.

The variation in CO2 flux from the forest floor is important in understanding the role of mangrove forests as a carbon sink. To clarify the effects of soil temperature and tidal conditions on variation in CO2 flux, sediment–atmosphere CO2 fluxes were measured between June 2012 and May 2013. We used the closed chamber method for two plots, with a 0.5 m difference in elevation (B, high elevation; R-B, low elevation), in a mangrove forest in south-western Japan. CO2 fluxes were highest in the warm season and showed a weak positive correlation with soil temperature in both forests. Estimated monthly CO2 flux showed moderate seasonal variation in accordance with the exposure duration of the soil surface under tidal fluctuation. Additionally, measured CO2 flux and soil temperature were slightly higher in the R-B plot than the B plot, although estimated annual CO2 flux was higher in the B plot than the R-B plot due to different exposure durations. These results suggest that variation in the exposure duration of the forest floor, which changes seasonally and microgeographically, is important in evaluating the annual CO2 flux at a local scale and understanding the role of mangrove ecosystems as regulators of atmospheric CO2.

Depending on conditions, Chinese peasants strategically adopted one of two types of transactions: either a single one-time transaction without reference to any particular buyer, or repeated transactions dependent on one regular broker. Based on the different sizes of market zones and responding to seasonality, Chinese peasant households allotted their labour to maximize income and avert risk. Generally, in early modern China, the volume of exchanges among peasants was much greater than the volume of exchanges between peasants and merchants from towns. One-time transactions were dominant not only by the choice of peasants for concluding local transactions but also by the petit traders who connected villages and towns. Thus, price movements in local currencies such as copper coins in local marketplaces did not follow the movements of inter-regional trade made in silver. Maintaining the independence of local trade, local merchants established a system for settlements through account books and issued native notes to respond to chronic shortages of currency. In Japan, peasant households showed similar characteristics of seasonal allocation and division of intra-household labour, but in the nineteenth century were less dependent on local marketplaces and maintained more continuous relationships among villagers as well as with merchants from towns. The differences between China and Japan during the early modern era, when economies depended heavily on small-size peasant households with less specialization, reveals the inadequacy of conventional conceptions of markets such as Smithian growth, which ignore the differences between local trade and inter-regional trade, and underestimate the importance of proximate exchanges among peasants, which reflected their desire for a higher degree of freedom when making transactions.

This study set out to identify and analyse trends and seasonal variations of monthly global reported cases of the Middle East respiratory syndrome coronavirus (MERS-CoV). It also made a prediction based on the reported and extrapolated into the future by forecasting the trend. Finally, the study assessed contributions of various risk factors in the reported cases. The motivation for this study is that MERS-CoV remains among the list of blueprint priority and potential pandemic diseases globally. Yet, there is a paucity of empirical literature examining trends and seasonality as the available evidence is generally descriptive and anecdotal. The study is a time series analysis using monthly global reported cases of MERS-CoV by the World Health Organisation between January 2015 and January 2018. We decomposed the series into seasonal, irregular and trend components and identified patterns, smoothened series, generated predictions and employed forecasting techniques based on linear regression. We assessed contributions of various risk factors in MERS-CoV cases over time. Successive months of the MERS-CoV cases suggest a significant decreasing trend (P = 0.026 for monthly series and P = 0.047 for Quarterly series). The MERS-CoV cases are forecast to wane by end 2018. Seasonality component of the cases oscillated below or above the baseline (the centred moving average), but no association with the series over time was noted. The results revealed contributions of risk factors such as camel contact, male, old age and being from Saudi Arabia and Middle East regions to the overall reported cases of MERS-CoV. The trend component and several risk factors for global MERS-CoV cases, including camel contact, male, age and geography/region significantly affected the series. Our statistical models appear to suggest significant predictive capacity and the findings may well inform healthcare practitioners and policymakers about the underlying dynamics that produced the globally reported MERS-CoV cases.

Campylobacter is the primary agent of human bacterial gastroenteritis worldwide. In contrast to temperate zones, weather effects on Campylobacter prevalence in broilers under tropical conditions are under-researched. We examined the association between weather and Campylobacter prevalence in slaughtered broilers in Sri Lanka, a tropical country with weather variations led by monsoons. Each month (October 2009–July 2011), 20–30 broiler batches referring to two semi-automated slaughterhouses from five Sri Lankan provinces were tested for Campylobacter contamination and analysed in relation to temperature, humidity and rainfall. Overall prevalence was 63.8% (95% CI 59.6–67.9%, n = 542), peaking in September–November. Each 1 °C increase in monthly mean temperature up to 26 °C increased Campylobacter-positive batches by 16.4% (95% CI 0.4–35.1%). For each 10 mm increase in monthly total rainfall up to 300 mm, Campylobacter-positive batches increased significantly by 0.8% (0.1–1.5%) at 1-month lag. For each 1% increase in relative humidity up to 80% at 1- and 2-month lags, Campylobacter-positive batches increased of respectively 4.2% (1.9–6.7%) and 4.0% (1.5–6.5), and decreased by 3.6% (2.6–4.6%) and 4.0% (2.6–5.4%) for unit increases above 80%. These results suggest that even in tropical countries without marked seasons, there are weather effects possibly reflecting Campylobacter potential to colonise its preferred host and/or survive in the environment.

The Suape coastal zone has suffered since the 1980s the effects of anthropogenic action due to the construction of the industrial complex of Suape. This work aimed to evaluate the environmental conditions and possible eutrophication processes of the area. Six campaigns were carried out, three in the dry season (November 2015, January and April 2016) and three in the rainy season (July 2015, July and August 2016). Water samples were collected at the surface during low tide and high tide, in neap tides. Salinity ranged from 19.75 to 37.20, the dissolved oxygen rate ranged from 61.75 to 125.90% and chlorophyll-a from 0.02 to 3.48 mg m−3. Water transparency, temperature, nitrate and silicate presented significant seasonal variation, the concentrations of nutrients being higher in the rainy season and the others in the dry season. Water transparency, salinity, dissolved oxygen saturation and chl-a <20 µm showed significant differences for tide, being higher at high tide, and at low tide for chl-a of <20 µm. The low content of dissolved inorganic nutrient salts and chl-a were indicative of an area still free of eutrophication. Anthropogenic changes in the environment have led to greater marine interference and consequently to a reduction of the productive capacity of the system.