scholarly journals Habitat selection drives dietary specialisation in Sorex minutus

2020 ◽  
Author(s):  
Roselyn L. Ware ◽  
Annie L. Booker ◽  
Francesca R. Allaby ◽  
Robin G. Allaby

AbstractTo meet their demand for food, Eurasian pygmy shrews (Sorex minutus) require large territories, normally in fields, woodlands, and meadows. Their high metabolism and food requirement often leads to high mortality during winter. However, evidence of shrews in the roof voids of residential buildings has recently been observed, contrary to ecological expectations. Here, five faecal samples collected from different locations were studied by metagenomic analysis to gain information about the shrew’s diets and environments. Two of the samples were collected from novel indoor locations, while the other three were from outdoors in ‘traditional’ habitats. Distinct differences were observed between the diets of the two populations, suggesting a commensal niche expansion has occurred in S. minutus. We found that S. minutus exploit man-made spaces for foraging, potentially at the cost of a greater parasite burden.

2019 ◽  
Author(s):  
Flore Zélé ◽  
Mustafa Altintaş ◽  
Inês Santos ◽  
Ibrahim Cakmak ◽  
Sara Magalhães

ABSTRACTMany studies have revealed the ability of the endosymbiotic bacteria Wolbachia to protect its arthropod hosts against diverse pathogens. However, as Wolbachia may also increase the susceptibility of its host to infection, predicting the outcome of a particular Wolbachia-host-pathogen interaction remains elusive. Yet, understanding such interactions is crucial for disease and pest control strategies. Tetranychus urticae spider mites are herbivorous crop pests, causing severe damage on numerous economically important crops. Due to the rapid evolution of pesticide resistance, biological control strategies using generalist entomopathogenic are being developed. However, although spider mites are infected with various Wolbachia strains worldwide, whether this endosymbiont protects them from fungi is as yet unknown. Here, we compared the survival of two populations, treated with antibiotics or harbouring different Wolbachia strains, after exposure to the fungal biocontrol agents Metarhizium brunneum and Beauveria bassiana. In one population, Wolbachia affected survival in absence of fungi but not in their presence, whereas in the other population Wolbachia increased the mortality induced by B. bassiana. To control for potential effects of the bacterial community of spider mites, we also compared the susceptibility of two populations naturally uninfected by Wolbachia, treated with antibiotics or not. The antibiotic treatment increased the susceptibility of spider mites to M. brunneum in one naturally Wolbachia-uninfected population, but it had no effect in the other treatments. These results highlight the complexity of within-host pathogens interactions, and the importance of considering the whole bacterial community of arthropods when assessing the effect of Wolbachia in a particular system.


2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.


2020 ◽  
Vol 3 (1) ◽  
pp. 61
Author(s):  
Kazuhiro Aruga

In this study, two operational methodologies to extract thinned woods were investigated in the Nasunogahara area, Tochigi Prefecture, Japan. Methodology one included manual extraction and light truck transportation. Methodology two included mini-forwarder forwarding and four-ton truck transportation. Furthermore, a newly introduced chipper was investigated. As a result, costs of manual extractions within 10 m and 20 m were JPY942/m3 and JPY1040/m3, respectively. On the other hand, the forwarding cost of the mini-forwarder was JPY499/m3, which was significantly lower than the cost of manual extractions. Transportation costs with light trucks and four-ton trucks were JPY7224/m3 and JPY1298/m3, respectively, with 28 km transportation distances. Chipping operation costs were JPY1036/m3 and JPY1160/m3 with three and two persons, respectively. Finally, the total costs of methodologies one and two from extraction within 20 m to chipping were estimated as JPY9300/m3 and JPY2833/m3, respectively, with 28 km transportation distances and three-person chipping operations (EUR1 = JPY126, as of 12 August 2020).


2021 ◽  
Vol 95 ◽  
Author(s):  
D. Rubel ◽  
N. Flaibani

Abstract The aim of this study was to explore through cross-sectional study the variation in the prevalence of parasitic helminths in canine faeces collected from green spaces of Buenos Aires according to the human density (HD) and economic level (EL) in the surroundings. HD and EL were considered as independent variables with three categories each. Twenty public squares (one hectare of surface) were randomly selected for each existing combination of the two independent variables. Ten random samples of fresh canine faeces were obtained in each square and analysed for helminths by the sedimentation and flotation techniques. The prevalence for each of the species was analysed using generalized linear models (GLM). The prevalence was modelled with a binomial error distribution and a logit link function. Helminth eggs were detected in 45 out of the 200 (22.5%) faecal samples collected and in 18 of the 20 green spaces sampled. The species observed were Ancylostoma caninum (13% of samples), Trichuris vulpis (8%) and Toxocara canis (4.5%). The GLM indicated that the prevalence of A. caninum in the slum areas (very high HD and very low EL) was higher than that in the other areas studied. However, the HD seemed to contribute more than the EL to the variations in the prevalence of A. caninum in faecal samples. The GLM showed no differences in the prevalence of the other parasite species for the different levels of the independent variables.


Games ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 53
Author(s):  
Roberto Rozzi

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough.


2014 ◽  
Vol 665 ◽  
pp. 643-646
Author(s):  
Ying Liu ◽  
Yan Ye ◽  
Chun Guang Li

Metalearning algorithm learns the base learning algorithm, targeted for improving the performance of the learning system. The incremental delta-bar-delta (IDBD) algorithm is such a metalearning algorithm. On the other hand, sparse algorithms are gaining popularity due to their good performance and wide applications. In this paper, we propose a sparse IDBD algorithm by taking the sparsity of the systems into account. Thenorm penalty is contained in the cost function of the standard IDBD, which is equivalent to adding a zero attractor in the iterations, thus can speed up convergence if the system of interest is indeed sparse. Simulations demonstrate that the proposed algorithm is superior to the competing algorithms in sparse system identification.


2010 ◽  
Vol 26 (2) ◽  
pp. 170-174 ◽  
Author(s):  
Shin Yuh Ang ◽  
Rachel Woo Yin Tan ◽  
Mariko Siyue Koh ◽  
Jeremy Lim

Objectives: Endobronchial ultrasound (EBUS), encompassing endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and Endobronchial ultrasound transbronchial lung biopsy (EBUS-TBLB) has been proven to be a useful modality in the staging and diagnosis of lung cancer. However, there are limited publications on the cost-effectiveness of EBUS and no economic evaluations relevant to the Singapore setting. An economic evaluation using our hospital's data was used to assess the cost implications of EBUS substituting where clinically appropriate: transthoracic needle aspiration; (TTNA), fluoroscopy-guided transbronchial lung biopsy (TBLB), and mediastinoscopy in the diagnosis and staging of lung cancer.Methods: Relationship between the clinical and economic implications of alternative modalities was modeled using data inputs that were relevant to the Singapore setting. Two decision analytic models were constructed to evaluate the cost of EBUS compared with TTNA, TBLB, and staging mediastinoscopy. Only direct costs were imputed.Results: In the base–case analysis, TTNA was the most economical strategy (SGD3,335 = US$2,403) where clinically suitable for the diagnosis of lung cancer as compared to the other options: TBLB (SGD4,499) and EBUS-TBLB (SGD4,857). On the other hand, EBUS-TBNA resulted in expected cost savings of SGD1,214 per positive staging of lung cancer as compared to mediastinoscopy.Conclusions: The use of EBUS-TBNA could result in cost savings of SGD1,214 per positive staging of lung cancer as compared to mediastinoscopy. Whereas TTNA was the most economical intervention for the diagnosis of lung cancer as compared to the other options, its main limitation lies in its suitability only for peripheral lung lesions and high complication rate.


PEDIATRICS ◽  
1990 ◽  
Vol 86 (2) ◽  
pp. 323-323
Author(s):  
CHUNG-PIN SHEIH ◽  
CHING-YUANG LIN

In Reply.— In our article, we reported on 645 renal abnormalities found in 132 686 school children screened through the use of renal ultrasonography. Of those with renal abnormalities, 50 patients had surgically correctable lesions. The other 595 cases have been examined fully to establish the correct diagnosis and the prevalence of renal abnormalities in school children. However, in this study, the cost to benefit ratio was determined by total expense to number of surgically treatable diseases.


Author(s):  
Mingwen Yang ◽  
Zhiqiang (Eric) Zheng ◽  
Vijay Mookerjee

Online reputation has become a key marketing-mix variable in the digital economy. Our study helps managers decide on the effort they should use to manage online reputation. We consider an online reputation race in which it is important not just to manage the absolute reputation, but also the relative rating. That is, to stay ahead, a firm should try to have ratings that are better than those of its competitors. Our findings are particularly significant for platform owners (such as Expedia or Yelp) to strategically grow their base of participating firms: growing the middle of the market (firms with average ratings) is the best option considering the goals of the platform and the other stakeholders, namely incumbents and consumers. For firms, we find that they should increase their effort when the mean market rating increases. Another key insight for firms is that, sometimes, adversity can come disguised as an opportunity. When an adverse event strikes the industry (such as a reduction in sales margin or an increase in the cost of effort), a firm’s profit can increase if it can manage this event better than its competitors.


2021 ◽  
Author(s):  
Coen Teunissen ◽  
Isabella Voce

This report estimates the cost of pure cybercrime to individuals in Australia in 2019. A survey was administered to a sample of 11,840 adults drawn from two online panels—one using probability sampling and the other non-probability sampling—with the resulting data weighted to better reflect the distribution of the wider Australian population. Thirty-four percent of respondents had experienced some form of pure cybercrime, with 14 percent being victimised in the last 12 months. This is equivalent to nearly 6.7 million Australian adults having ever been the victim of pure cybercrime, and 2.8 million Australians being victimised in the past year. Drawing on these population estimates, the total economic impact of pure cybercrime in 2019 was approximately $3.5b. This encompasses $1.9b in money directly lost by victims, $597m spent dealing with the consequences of victimisation, and $1.4b spent on prevention costs. Victims recovered $389m.


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