Search results for "season"

Destination engagement on Facebook: Time and seasonality

2019

Abstract This paper studies the influence of time frames (posting day and posting time) and seasonality (low, medium and high) on positive/negative engagement in a Destination Management Organization (DMO) on Facebook. A content analysis was carried out on 639 posts, 178,913 audience reactions to such posts and 5330 comments. These posts were shared 45,194 times by the audience. The data analysis (regression analyses with optimal scaling) suggests that the best times to post are at 8  am , 10  am , 2  pm and 5  pm ; Thursday and Saturday are the best days to post, and the period before summer (from January to June) are the best months. These results have implications for DMOs and National T…

Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest

2012

Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …

Serological Follow-Up Study Indicates High Seasonal Coronavirus Infection and Reinfection Rates in Early Childhood

2022

Seasonal human coronaviruses (HCoVs) cause respiratory infections, especially in children. Currently, the knowledge on early childhood seasonal coronavirus infections and the duration of antibody levels following the first infections is limited. Here we analyzed serological follow-up samples to estimate the rate of primary infection and reinfection(s) caused by seasonal coronaviruses in early childhood. Serum specimens were collected from 140 children at ages of 13, 24, and 36 months (1, 2, and 3 years), and IgG antibody levels against recombinant HCoV nucleoproteins (N) were measured by enzyme immunoassay (EIA). Altogether, 84% (118/140) of the children were seropositive for at least one s…

Comparison between SMOS Vegetation Optical Depth products and MODIS vegetation indices over crop zones of the USA

2014

The Soil Moisture and Ocean Salinity (SMOS) mission provides multi-angular, dual-polarised brightness temperatures at 1.4 GHz, from which global soil moisture and vegetation optical depth (tau) products are retrieved. This paper presents a study of SMOS' tau product in 2010 and 2011 for crop zones of the USA. Retrieved tau values for 504 crop nodes were compared to optical/IR vegetation indices from the MODES (Moderate Resolution Imaging Spectroradiometer) satellite sensor, including the Normalised Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVE), Leaf Area Index (LAI), and a Normalised Difference Water Index (NOW!) product. tau values were observed to increase during the…

Effect of mycorrhizal inoculation on metal accumulation by poplar leaves at phytomanaged sites

2017

Abstract Phytotechnologies for the management of lands contaminated with potentially toxic elements (PTEs) are considered as gentle alternatives to conventional remediation techniques. During the last few years, phytotechnologies have progressively shifted to phytomanagement, a concept that includes the valorization of the plant biomass produced on the contaminated site. This study aimed at evaluating the mid-term effect of ecto- and endomycorrhizal inoculation on the reduction of PTE mobility in soils and foliar accumulation by two poplar clones, Skado ( Populus trichocarpa x P. maximowiczii ) and I-214 ( P. deltoides x P. nigra ), dedicated to bioenergy purposes. The effects of inoculatio…

Seasonal evolution of the quality of fresh glasshouse tomatoes under Mediterranean conditions, as affected by air vapour pressure deficit and plant f…

2000

Abstract Changes in yield and quality of fresh tomatoes in response to air vapour pressure deficit (VPD) and plant fruit load were studied under Mediterranean summer conditions. Plants thinned to three or six fruits per truss were grown in two compartments, one at a VPD below 1.5 kPa, the other without VPD control. The seasonal trend in fruit yield and quality was assessed from April to September by weekly measurement of number, fresh weight and dry matter content of harvested fruits, together with the occurrence of blossom-end-rot (BER) and cracking. On two occasions, in July and September, sugar and acid content was measured at three ripening stages. The seasonal decrease in fresh yield w…

Plant removal disturbance and replant mitigation effects on the abundance and diversity of low-arctic soil biota

2014

Abstract Due to the dependence of soil organisms on plant derived carbon, disturbances in plant cover are thought to be detrimental for the persistence of soil biota. In this work, we studied the disturbance effects of plant removal and soil mixing and the mitigation effects of replanting on soil biota in a low-arctic meadow ecosystem. We set up altogether six replicate blocks, each including three randomized treatment plots, at two distinct fells at Kilpisjarvi, northern Finland. Vegetation was removed in two thirds of the plots: one third was then kept barren (the plant-removal treatment), while the other third was replanted with a local herb Solidago virgaurea. The remaining plots of int…

State-dependent foraging: lactating voles adjust their foraging behavior according to the presence of a potential nest predator and season

2015

Parental care often produces a trade-off between meeting nutritional demands of offspring and the duties of offspring protection, especially in altricial species. Parents have to leave their young unattended for foraging trips, during which nestlings are exposed to predators. We investigated how rodent mothers of altricial young respond to risk of nest predation in their foraging decisions. We studied foraging behavior of lactating bank voles (Myodes glareolus) exposed to a nest predator, the common shrew (Sorex araneus). We conducted the experiment in summer (high resource provisioning for both species) and autumn (less food available) in 12 replicates with fully crossed factors “shrew pre…

Climatic gradients along the windward slopes of Mount Kenya and their implication for crop risks. Part 1: climate variability

2012

In tropical mountains, the way topographical gradients translate in terms of intra-seasonal and interannual climate variability (especially rainfall and evapotranspiration) is relatively unknown, yet it is an important issue for agriculture and food security. The eastern slopes of Mount Kenya, in East Africa, with their wide range of agro-ecological conditions, are appropriate for the study of these aspects. Daily (monthly) rainfall data from 11 (24) stations at different elevations and exposures are collected for the period 1961-2006. For the elevation belts suitable for farming and agro-pastoral activities, mostly below 2000 m, it is found that not all rainfall characteristics co-vary wit…

2017

AbstractFuture changes in the structure of daily rainfall, especially the number of rainy days and the intensity of extreme events, are likely to induce major impacts on rain-fed agriculture in the tropics. In Africa this issue is of primary importance, but the agreement between climate models to simulate such descriptors of rainfall is generally poor. Here, we show that the climate models used for the fifth assessment report of IPCC simulate a marked decrease in the number of rainy days, together with a strong increase in the rainfall amounts during the 1% wettest days, by the end of the 21st century over Southern Africa. These combined changes lead to an apparent stability of seasonal tot…