Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Broussonetia papyrifera is an exotic tree widely grown for paper production. Due to its prolific regeneration it has invaded forestcanopy gaps and degraded farmlands and has now become an invasive species in Ghana. In enhancing its value for use the plantwas evaluated as potential forage for grazing animals vis-à-vis other two existing forage plants: Ficus exasperata and Leucaenaleucocephala.The study assessed the palatability and preference of Broussonetia papyrifera using sheep and goats for the wet anddry seasons.The species were assessed in indoor pen feeding trials using eight-unit (3×3 m) pens with the cafeteria method.The amount of forage offered was 100g (fresh material) in all instances for each species and for ten minutes. Adesign basedon 3×2×2 factorial in Randomized Complete Block Design (RCBD) was used to test the differences in palatability betweenthe three forage species.Results revealed that palatability was higher (P<0.05) in Leucaena leucocephala compared with Ficusexasperata and Broussonetia papyrifera for sheep and goats across seasons. The trend shown might be the result of the effectsof familiarity with the Leucaena leucocephala since animals tend to select plants that are familiar than newly introduced andunfamiliar plants. The study also revealed high level of condensed tannin (CT) in Broussonetia papyrifera which might haveinterfered with forage intake by the animals.There were no significant differences in palatability of Broussonetia papyrifera forgoat in both dry and wet season interactions and Ficus exasperata for goat in both dry and wet season interactions (P>0.05).Thestudy concluded that Broussonetia papyrifera could be a potential feed for both sheep and goats across seasons.The researchrecommended that livestock farmers should incorporate Broussonetia papyrifera feed into their programmes for both sheep andgoats and should be introduced to animals from infancy so that it may become a familiar feed for them.

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Vietnamese Historical Writing

10.1093/oso/9780199225996.003.0028 ◽

2018 ◽

Author(s):

Patricia Pelley

Keyword(s):

Cold War ◽

East Asian ◽

History Writing ◽

Southern State ◽

The Past ◽

South Vietnam ◽

Political Function ◽

Different Types ◽

The Cold War ◽

North Vietnam

This chapter demonstrates how the process of decolonization and the ensuing separation of Vietnam into a northern and southern state as part of the Cold War in Asia led to different types of history-writing. In both Vietnamese regimes, the writing of history had to serve the state, and in both countries historians emphasized its political function. Whereas North Vietnam located itself in an East Asian and Marxist context, historians of South Vietnam positioned it within a Southeast Asian setting and took a determinedly anti-communist position. After 1986—over a decade after reunification—with past tensions now relaxed, the past could be revaluated more openly under a reformist Vietnamese government that now also permitted much greater interaction with foreign historians.

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Contrasting capabilities of two ungulate species to cope with extremes of aridity

Scientific Reports ◽

10.1038/s41598-021-83732-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Melinda Boyers ◽

Francesca Parrini ◽

Norman Owen-Smith ◽

Barend F. N. Erasmus ◽

Robyn S. Hetem

Keyword(s):

Climate Change ◽

High Water ◽

Future Climate Change ◽

Body Temperatures ◽

Wet Season ◽

Trade Off ◽

Ambient Temperatures ◽

Mammalian Herbivores ◽

Dry Seasons ◽

Connochaetes Taurinus

AbstractSouthern Africa is expected to experience increased frequency and intensity of droughts through climate change, which will adversely affect mammalian herbivores. Using bio-loggers, we tested the expectation that wildebeest (Connochaetes taurinus), a grazer with high water-dependence, would be more sensitive to drought conditions than the arid-adapted gemsbok (Oryx gazella gazella). The study, conducted in the Kalahari, encompassed two hot-dry seasons with similar ambient temperatures but differing rainfall patterns during the preceding wet season. In the drier year both ungulates selected similar cooler microclimates, but wildebeest travelled larger distances than gemsbok, presumably in search of water. Body temperatures in both species reached lower daily minimums and higher daily maximums in the drier season but daily fluctuations were wider in wildebeest than in gemsbok. Lower daily minimum body temperatures displayed by wildebeest suggest that wildebeest were under greater nutritional stress than gemsbok. Moving large distances when water is scarce may have compromised the energy balance of the water dependent wildebeest, a trade-off likely to be exacerbated with future climate change.

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Sensitivity Analysis of Sentinel-1 Backscatter to Oil Palm Plantations at Pluriannual Scale: A Case Study in Gabon, Africa

Remote Sensing ◽

10.3390/rs13112075 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2075

Author(s):

J. David Ballester-Berman ◽

Maria Rastoll-Gimenez

Keyword(s):

Time Series ◽

Sensitivity Analysis ◽

Oil Palm ◽

Time Interval ◽

Potential Candidate ◽

Initial Growth ◽

Natural Forests ◽

Wet Season ◽

Radar Signatures ◽

The Times

The present paper focuses on a sensitivity analysis of Sentinel-1 backscattering signatures from oil palm canopies cultivated in Gabon, Africa. We employed one Sentinel-1 image per year during the 2015–2021 period creating two separated time series for both the wet and dry seasons. The first images were almost simultaneously acquired to the initial growth stage of oil palm plants. The VH and VV backscattering signatures were analysed in terms of their corresponding statistics for each date and compared to the ones corresponding to tropical forests. The times series for the wet season showed that, in a time interval of 2–3 years after oil palm plantation, the VV/VH ratio in oil palm parcels increases above the one for forests. Backscattering and VV/VH ratio time series for the dry season exhibit similar patterns as for the wet season but with a more stable behaviour. The separability of oil palm and forest classes was also quantitatively addressed by means of the Jeffries–Matusita distance, which seems to point to the C-band VV/VH ratio as a potential candidate for discrimination between oil palms and natural forests, although further analysis must still be carried out. In addition, issues related to the effect of the number of samples in this particular scenario were also analysed. Overall, the outcomes presented here can contribute to the understanding of the radar signatures from this scenario and to potentially improve the accuracy of mapping techniques for this type of ecosystems by using remote sensing. Nevertheless, further research is still to be done as no classification method was performed due to the lack of the required geocoded reference map. In particular, a statistical assessment of the radar signatures should be carried out to statistically characterise the observed trends.

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The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽

10.1186/s12864-021-07372-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Xue Zhu ◽

Jiyue Qin ◽

Chongyang Tan ◽

Kang Ning

Keyword(s):

Gut Microbiome ◽

Seasonal Changes ◽

Dry Season ◽

Urban Setting ◽

Snp Analysis ◽

Wet Season ◽

Human Gut ◽

Human Gut Microbiome ◽

Genome Level ◽

Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

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Cloud Radar Observations of Diurnal and Seasonal Cloudiness over Reunion Island

Atmosphere ◽

10.3390/atmos12070868 ◽

2021 ◽

Vol 12 (7) ◽

pp. 868

Author(s):

Jonathan Durand ◽

Edouard Lees ◽

Olivier Bousquet ◽

Julien Delanoë ◽

François Bonnardot

Keyword(s):

Sea Breeze ◽

Satellite System ◽

Research Infrastructure ◽

Weather Data ◽

Reunion Island ◽

Wet Season ◽

Trade Winds ◽

Cloud Radar ◽

Réunion Island ◽

Global Navigation Satellite

In November 2016, a 95 GHz cloud radar was permanently deployed in Reunion Island to investigate the vertical distribution of tropical clouds and monitor the temporal variability of cloudiness in the frame of the pan-European research infrastructure Aerosol, Clouds and Trace gases Research InfraStructure (ACTRIS). In the present study, reflectivity observations collected during the two first years of operation (2016–2018) of this vertically pointing cloud radar are relied upon to investigate the diurnal and seasonal cycle of cloudiness in the northern part of this island. During the wet season (December–March), cloudiness is particularly pronounced between 1–3 km above sea level (with a frequency of cloud occurrence of 45% between 12:00–19:00 LST) and 8–12 km (with a frequency of cloud occurrence of 15% between 14:00–19:00 LST). During the dry season (June–September), this bimodal vertical mode is no longer observed and the vertical cloud extension is essentially limited to a height of 3 km due to both the drop-in humidity resulting from the northward migration of the ITCZ and the capping effect of the trade winds inversion. The frequency of cloud occurrence is at its maximum between 13:00–18:00 LST, with a probability of 35% at 15 LST near an altitude of 2 km. The analysis of global navigation satellite system (GNSS)-derived weather data also shows that the diurnal cycle of low- (1–3 km) and mid-to-high level (5–10 km) clouds is strongly correlated with the diurnal evolution of tropospheric humidity, suggesting that additional moisture is advected towards the island by the sea breeze regime. The detailed analysis of cloudiness observations collected during the four seasons sampled in 2017 and 2018 also shows substantial differences between the two years, possibly associated with a strong positive Indian Ocean Southern Dipole (IOSD) event extending throughout the year 2017.

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Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽

10.3390/d13070319 ◽

2021 ◽

Vol 13 (7) ◽

pp. 319

Author(s):

Cristian Pérez-Granados ◽

Karl-L. Schuchmann

Keyword(s):

Air Temperature ◽

Daily Rainfall ◽

Climatic Conditions ◽

Dry Season ◽

Climate Impacts ◽

Calling Behavior ◽

Wet Season ◽

Focal Species ◽

Calling Activity ◽

Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

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Biomass Burning and Water Balance Dynamics in the Lake Chad Basin in Africa

Earth ◽

10.3390/earth2020020 ◽

2021 ◽

Vol 2 (2) ◽

pp. 340-356

Author(s):

Forrest W. Black ◽

Jejung Lee ◽

Charles M. Ichoku ◽

Luke Ellison ◽

Charles K. Gatebe ◽

...

Keyword(s):

Water Balance ◽

Biomass Burning ◽

Water Cycle ◽

Potential Evapotranspiration ◽

Southern Oscillation ◽

Wet Season ◽

Lake Chad ◽

Chad Basin ◽

Lake Chad Basin ◽

Logone Catchment

The present study investigated the effect of biomass burning on the water cycle using a case study of the Chari–Logone Catchment of the Lake Chad Basin (LCB). The Chari–Logone catchment was selected because it supplies over 90% of the water input to the lake, which is the largest basin in central Africa. Two water balance simulations, one considering burning and one without, were compared from the years 2003 to 2011. For a more comprehensive assessment of the effects of burning, albedo change, which has been shown to have a significant impact on a number of environmental factors, was used as a model input for calculating potential evapotranspiration (ET). Analysis of the burning scenario showed that burning grassland, which comprises almost 75% of the total Chari–Logone land cover, causes increased ET and runoff during the dry season (November–March). Recent studies have demonstrated that there is an increasing trend in the LCB of converting shrubland, grassland, and wetlands to cropland. This change from grassland to cropland has the potential to decrease the amount of water available to water bodies during the winter. All vegetative classes in a burning scenario showed a decrease in ET during the wet season. Although a decrease in annual precipitation in global circulation processes such as the El Niño Southern Oscillation would cause droughts and induce wildfires in the Sahel, the present study shows that a decrease in ET by the human-induced burning would cause a severe decrease in precipitation as well.

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An update on the distribution of Glossina (tsetse flies) at the wildlife-human-livestock interface of Akagera National Park, Rwanda

Parasites & Vectors ◽

10.1186/s13071-021-04786-3 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Richard S. Gashururu ◽

Samuel M. Githigia ◽

Methode N. Gasana ◽

Richard Habimana ◽

Ndichu Maingi ◽

...

Keyword(s):

National Park ◽

Control Strategies ◽

Glossina Pallidipes ◽

Distribution Patterns ◽

Tsetse Flies ◽

Wet Season ◽

Chi Square ◽

Large Numbers ◽

Surrounding Areas ◽

Biconical Traps

Abstract Background Glossina (tsetse flies) biologically transmit trypanosomes that infect both humans and animals. Knowledge of their distribution patterns is a key element to better understand the transmission dynamics of trypanosomosis. Tsetse distribution in Rwanda has not been well enough documented, and little is known on their current distribution. This study determined the current spatial distribution, abundance, diversity, and seasonal variations of tsetse flies in and around the Akagera National Park. Methods A longitudinal stratified sampling following the seasons was used. Biconical traps were deployed in 55 sites for 6 consecutive days of each study month from May 2018 to June 2019 and emptied every 48 h. Flies were identified using FAO keys, and the number of flies per trap day (FTD) was used to determine the apparent density. Pearson chi-square (χ2) and parametrical tests (t-test and ANOVA) were used to determine the variations between the variables. The significance (p < 0.05) at 95% confidence interval was considered. Logistic regression was used to determine the association between tsetse occurrence and the associated predictors. Results A total of 39,516 tsetse flies were collected, of which 73.4 and 26.6% were from inside Akagera NP and the interface area, respectively. Female flies accounted for 61.3 while 38.7% were males. Two species were identified, i.e. G. pallidipes [n = 29,121, 7.4 flies/trap/day (FTD)] and G. morsitans centralis (n = 10,395; 2.6 FTD). The statistical difference in numbers was significant between the two species (p = 0.000). The flies were more abundant during the wet season (15.8 FTD) than the dry season (4.2 FTD). Large numbers of flies were trapped around the swamp areas (69.1 FTD) inside the park and in Nyagatare District (11.2 FTD) at the interface. Glossina morsitans was 0.218 times less likely to occur outside the park. The chance of co-existing between the two species reduced outside the protected area (0.021 times). Conclusions The occurrence of Glossina seems to be limited to the protected Akagera NP and a narrow band of its surrounding areas. This finding will be crucial to design appropriate control strategies. Glossina pallidipes was found in higher numbers and therefore is conceivably the most important vector of trypanosomosis. Regional coordinated control and regular monitoring of Glossina distribution are recommended. Graphic Abstract

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Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽

10.3390/w13030320 ◽

2021 ◽

Vol 13 (3) ◽

pp. 320

Author(s):

Qianyao Si ◽

Mary G. Lusk ◽

Patrick W. Inglett

Keyword(s):

Removal Efficiency ◽

N Mineralization ◽

Inorganic Nitrogen ◽

Dry Season ◽

Pollutant Removal ◽

Net N Mineralization ◽

Wet Season ◽

Inorganic N ◽

N Removal ◽

Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

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