scholarly journals Top predators suppress rather than facilitate plants in a trait-mediated tri-trophic cascade

2011 ◽  
Vol 7 (5) ◽  
pp. 710-713 ◽  
Author(s):  
John N. Griffin ◽  
Jack Butler ◽  
Nicole N. Soomdat ◽  
Karen E. Brun ◽  
Zachary A. Chejanovski ◽  
...  
Keyword(s):  
Salt Marshes ◽  
Spatially Explicit ◽  
Habitat Shift ◽  
Feeding Rates ◽  
Top Predators ◽  
The Mean ◽  
Hunting Mode ◽  
Positive Effect ◽  
Predation Refuge ◽  
Do So

Classical ecological theory states that in tri-trophic systems, predators indirectly facilitate plants by reducing herbivore densities through consumption, while more recent work has revealed that predators can generate the same positive effect on plants non-consumptively by inducing changes in herbivore traits (e.g. feeding rates). Based on observations in US salt marshes dominated by vast monocultures of cordgrass, we hypothesized that sit-and-wait substrate-dwelling predators (crabs) could actually strengthen per capita impacts of potent grazers (snails), by non-consumptively inducing a vertical habitat shift of snails to their predation refuge high on canopy leaves that are vulnerable to grazing. A two-month field experiment supported this hypothesis, revealing that predators non-consumptively increased the mean climbing height of snails on grasses, increased grazing damage per leaf and ultimately suppressed cordgrass biomass, relative to controls. While seemingly counterintuitive, our results can be explained by (i) the vulnerability of refuge resources to grazing, and (ii) universal traits that drove the vertical habitat shift—i.e. relative habitat domains of predator and prey, and the hunting mode of the top predator. These results underline the fact that not only should we continue to incorporate non-consumptive effects into our understanding of top-down predator impacts, but we should do so in a spatially explicit manner.

scholarly journals An Empirical Study of Some Driving Factors of CO2 Emissions: Evidence from Quantile Regression

2020 ◽  
pp. 87-95
Author(s):  
Yaya KEHO
Keyword(s):  
Quantile Regression ◽  
Co2 Emissions ◽  
Environmental Kuznets Curve ◽  
Kuznets Curve ◽  
Regression Methods ◽  
High Pollution ◽  
The Mean ◽  
Openness To Trade ◽  
Positive Effect ◽  
Do So

A growing body of research has examined the determinants of CO2 emissions. This literature has used mean-based regression methods in which only the mean effects of covariates are estimated. In this paper, we use the quantile regression methodology for a panel of 45 countries to investigate whether or not the factors that drive pollution do so in the same way for high and low pollution countries. The Environmental Kuznets Curve is confirmed and the positive effect of economic development is larger in low pollution countries. Energy consumption and financial development increase CO2 emissions and their effects are larger in countries with lower levels of pollution. Industrialization increases pollution especially in countries with higher level of pollution. Openness to trade and urbanization are negatively related to emissions in low pollution countries. All these findings suggest that pollution control policies should be tailored differently across low and high pollution countries.

scholarly journals Behavior Modeling for a Beacon-Based Indoor Location System

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4839
Author(s):  
Aritz Bilbao-Jayo ◽  
Aitor Almeida ◽  
Ilaria Sergi ◽  
Teodoro Montanaro ◽  
Luca Fasano ◽  
...  
Keyword(s):  
Behavior Modeling ◽  
Percentage Error ◽  
Location Prediction ◽  
Indoor Environments ◽  
Prediction System ◽  
Indoor Location ◽  
The Mean ◽  
Locating System ◽  
Monitoring Devices ◽  
Do So

In this work we performed a comparison between two different approaches to track a person in indoor environments using a locating system based on BLE technology with a smartphone and a smartwatch as monitoring devices. To do so, we provide the system architecture we designed and describe how the different elements of the proposed system interact with each other. Moreover, we have evaluated the system’s performance by computing the mean percentage error in the detection of the indoor position. Finally, we present a novel location prediction system based on neural embeddings, and a soft-attention mechanism, which is able to predict user’s next location with 67% accuracy.

62 Feeding Chicory-plantain Silage and Se-yeast to Lactating Ewes Subjected to Intramammary Infection: Effect on the Immune System

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 32-33
Author(s):  
Hunter Ford ◽  
Massimo Bionaz ◽  
Serkan Ates ◽  
Joe Klopfenstein ◽  
Jorge Vanegas ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Complete Blood Count ◽  
Random Effect ◽  
Mean Cell Volume ◽  
Distribution Width ◽  
Intramammary Infection ◽  
Alfalfa Meal ◽  
The Mean ◽  
To Receive ◽  
Positive Effect

Abstract The objective was to test the effect on the immune status by feeding a combination of chicory-plantain and Se-yeast in lactating ewes subjected to intramammary infection (IMI) with 2×107CFU of Strep uberis in both glands. For the purpose we enrolled 28 Polypay lactating sheep from a prior study where they were randomly allocated to receive chicory (CS) or grass (GC) silage and either 3.6 mg of Se/day as Se-yeast (DiaMune, Diamond V) (Y) or isoenergetic-isonitrogenous alfalfa meal (C) for 2 months. For the present study, ewes were kept on the original dietary regiment except the CT group received a chicory-plantain silage(50% each). Blood was collected prior to and for 10 days after IMI for a complete blood count(VetScan HM5), leukocytes migration, and rectal temperature (RT). Data were analyzed using GLIMMIX (SAS)with time, silage type, and Se and their interactions as the fixed effects and ewe as random effect with significance declared at P ≤ 0.05. RT was lower in chicory vs. grass before IMI and Se limited the RT increase after IMI. Total WBC levels tended (P = 0.06) to increase in animals fed with Se after IMI, which was driven by a larger number of lymphocytes. Hematocrit, red blood cells, and hemoglobin were strongly decreased by IMI. The mean cell volume was overall larger in ewes fed with chicory-plantain silage while mean cell hemoglobin was larger in animal fed with grass silage. The platelet distribution width was affected by silage*Se interaction due to a positive effect by Se in grass-fed but negative in chicory-plantain-fed ewes. Migration of neutrophils was larger in animals fed with chicory-plantain before IMI but similar between groups after IMI. Overall, these findings indicate that Se supplementation can increase lymphocytes with no effect on neutrophils while activity of neutrophils is positively affected by feeding chicory-plantain silage.

Results and Complications after Implantation of a Black Iris-Lens Diaphragm in Patients with Traumatically Induced Aphakia and Aniridia

2011 ◽  
Vol 21 (6) ◽  
pp. 754-759 ◽  
Author(s):  
Vasileios Petousis ◽  
Lothar Krause ◽  
Gregor Willerding ◽  
Michael H. Foerster ◽  
Nikolaos E. Bechrakis
Keyword(s):  
Anterior Chamber ◽  
Surgical Repair ◽  
Silicone Oil ◽  
Case Series ◽  
Corrected Visual Acuity ◽  
Time Out ◽  
Anatomic Results ◽  
The Mean ◽  
Positive Effect

Purpose. The black iris-lens diaphragm (ILD) can be used in the treatment of traumatic aniridia and aphakia. The aim of our study was to show postoperative functional and anatomic results and complications in a small case series. Methods. We retrospectively analyzed the files of 16 patients managed with a black ILD or a sole iris diaphragm in the period 1994–2007. Four of them were female and 12 were male. The mean age of the group was 50±17 years. At the time of the implantation, all of the eyes had already undergone primary surgical repair. Results. The preoperative best-corrected visual acuity in half of the patients was ≥0.1 and remained stable after the first postoperative year. During the follow-up years, one eye developed a subluxation of the implant and one eye an anterior chamber hemorrhage. At the same time, out of 8 eyes carrying a silicone tamponade in the vitreous cavity, silicone oil entered the anterior chamber in 3 cases. In one case, enucleation was undertaken due to phthisis. Conclusions. In the case of severely traumatized eyes with aniridia and aphakia, the implantation of a black ILD can have a positive effect on functional and anatomic stabilization.

scholarly journals Survival and osmoregulation of the purple marsh crab (Sesarma reticulatum) at varying salinity and pH

2017 ◽  
Vol 95 (12) ◽  
pp. 985-989 ◽  
Author(s):  
C.A. Shaughnessy ◽  
E.C. Anderson ◽  
M. Kasparian ◽  
J.M. LaMontagne ◽  
J.S. Bystriansky
Keyword(s):  
South Carolina ◽  
Salt Marshes ◽  
Trophic Cascade ◽  
Western Atlantic ◽  
Fundamental Niche ◽  
Ion Concentrations ◽  
Physiological Tolerance ◽  
Physiological Limits ◽  
Top Predators ◽  
Sesarma Reticulatum

Overfishing of top predators along the western Atlantic coastline has led to a trophic cascade in salt marshes, with increases in herbivorous purple marsh crab (Sesarma reticulatum (Say, 1817)) abundances in North American estuaries leading to overgrazing of cordgrass (Spartina alterniflora Loisel.) and shoreline erosion. To evaluate potential physiological limits on the range of S. reticulatum within an estuary, we evaluated survival and physiological tolerance of S. reticulatum from the Ashepoo–Combhee–Edisto (ACE) River Basin in South Carolina, USA, to combinations of salinity (5‰ and 30‰) and pH (pH 6.6, 7.6, and 8.6) challenges, representative of estuarine extremes. Survival, haemolymph ion concentrations, and gill Na+,K+-ATPase (NKA) and vacuolar-type H+-ATPase (VHA) activity were measured after a 48 h exposure to each experimental condition. Survival was nearly 100% and osmoregulatory control was maintained across estuarine salinity and pH ranges. Sesarma reticulatum appeared to be robust to all potential combinations of salinity and pH stressors examined in this study, and therefore are likely unrestricted in their fundamental niche based on these stressors throughout an estuary.

scholarly journals Uncertainty visualization of gaze estimation to support operator-controlled calibration

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Almoctar Hassoumi ◽  
Vsevolod Peysakhovich ◽  
Christophe Hurter
Keyword(s):  
Qualitative Evaluation ◽  
Point Of View ◽  
Angular Error ◽  
Qualitative Assessment ◽  
Gaze Estimation ◽  
Uncertainty Visualization ◽  
Estimation Uncertainty ◽  
The Mean ◽  
Gaze Position ◽  
Do So

      In this paper, we investigate how visualization assets can support the qualitative evaluation of gaze estimation uncertainty. Although eye tracking data are commonly available, little has been done to visually investigate the uncertainty of recorded gaze information. This paper tries to fill this gap by using innovative uncertainty computation and visualization. Given a gaze processing pipeline, we estimate the location of this gaze position in the world camera. To do so we developed our own gaze data processing which give us access to every stage of the data transformation and thus the uncertainty computation. To validate our gaze estimation pipeline, we designed an experiment with 12 participants and showed that the correction methods we proposed reduced the Mean Angular Error by about 1.32 cm, aggregating all 12 participants’ results. The Mean Angular Error is 0.25° (SD=0.15°) after correction of the estimated gaze. Next, to support the qualitative assessment of this data, we provide a map which codes the actual uncertainty in the user point of view. 

scholarly journals THE EFFECT OF TEAM PRODUCT TO IMPROVE STUDENTS’ CREATIVITY IN WRITING AT SMPN 1 JONGGAT

2020 ◽  
Vol 8 (1) ◽  
pp. 40
Author(s):  
Zukhairatunniswah Prayati
Keyword(s):  
Control Group ◽  
Product Method ◽  
8Th Grade ◽  
The Subject ◽  
The Mean ◽  
Inferential Analysis ◽  
And Control ◽  
Academic Year ◽  
Positive Effect ◽  
Experimental Group

This study investigated the effect of team product to improve students’ creativity in writing at the 8th-grade students of SMPN 1 Jonggat, Central Lombok in the academic year 2018/2019. The research was designed as quasi experiment research. The students were divided into the experimental group and control group. The experimental group was treated using the team product method while the control group was subjected to a conventional method. The data were analyzed using descriptive and inferential analysis. The data in this research was taken from the mean scores of students’ achievement and the score percentages. The subject of this research was the 8th-grade students of SMPN 1 Jonggat, which consisted of 54 students. The instruments of this research were tests and questionnaires. The mean score of students’ creativity in the experimental group was 75 and the writing skill was 76. It was higher than the students in the control group. It can be concluded that the team product had a positive effect on students’ writing skills in relation to creativity at SMPN 1 Jonggat.

scholarly journals Analysis of L-carnitine effectiveness in complex treat-ment of pregnant women with placental insufficiency

2021 ◽  
Vol 38 (5) ◽  
pp. 15-23
Author(s):  
G. H. Mamedli ◽  
G. I. Babaeva ◽  
M. E. Azizova ◽  
U. M. Sirajli ◽  
G. G. Hajizade
Keyword(s):  
Pregnant Women ◽  
Fetal Development ◽  
Placental Insufficiency ◽  
Complex Treatment ◽  
Fetal Blood ◽  
Mean Values ◽  
Treat Ment ◽  
The Mean ◽  
Positive Effect ◽  
Basic Treatment

Objective. To increase the effectiveness of treatment of placental insufficiency in pregnant women with the inclusion of L-carnitine (Inestom) in complex therapy. Materials and methods. A total of 76 pregnant women aged 18 to 39 years were examined at 2240 weeks of gestation. All the examined patients were divided into two groups. Patients of the first group (n = 37) received only basic treatment, which included the use of a complex of vasodilators, tocolytics, drugs that improve microcirculation and rheological properties of blood. Patients of the second group (n = 39) received L-carnitine along with basic therapy (Inestom, Help SA Pharmaceuticals, Greece). Results. The use of the drug Inestom as a part of the complex treatment of placental insufficiency led to the normalization of utero-placental-fetal blood flow and intrauterine fetal development in 94.7 % of pregnant women. After the course of drug therapy, there was an increase in the total score of cardiotography, which in the first group of patients was 7.08 0.06 before treatment and 7.13 0.11 after treatment (p 0.05), and in the second group 7.12 0.11 before treatment and 7.95 0.05 after (p 0.05). The results of antenatal dopplerometry showed that in pregnant women who received Inestom as a part of the complex treatment, there was a decrease in the mean values of all vascular resistance indices. Conclusions. The use of Inestom in the complex treatment of placental insufficiency has a positive effect on the state of hemodynamics in the "mother-placenta-fetus" system, and affects the intrauterine state of the fetus.

scholarly journals LINK OF MOMENTS BEFORE AND AFTER TRANSFORMATIONS, WITH AN APPLICATION TO RESAMPLING FROM FAT-TAILED DISTRIBUTIONS

2018 ◽  
Vol 35 (03) ◽  
pp. 630-652 ◽  
Author(s):  
Karim M. Abadir ◽  
Adriana Cornea-Madeira
Keyword(s):  
Finite Number ◽  
Confidence Intervals ◽  
Characteristic Functions ◽  
Infinite Variance ◽  
Fundamental Relation ◽  
Bootstrap Confidence Intervals ◽  
Finite Samples ◽  
Before And After ◽  
The Mean ◽  
Do So

Let x be a transformation of y, whose distribution is unknown. We derive an expansion formulating the expectations of x in terms of the expectations of y. Apart from the intrinsic interest in such a fundamental relation, our results can be applied to calculating E(x) by the low-order moments of a transformation which can be chosen to give a good approximation for E(x). To do so, we generalize the approach of bounding the terms in expansions of characteristic functions, and use our result to derive an explicit and accurate bound for the remainder when a finite number of terms is taken. We illustrate one of the implications of our method by providing accurate naive bootstrap confidence intervals for the mean of any fat-tailed distribution with an infinite variance, in which case currently available bootstrap methods are asymptotically invalid or unreliable in finite samples.

Burbot: Ecology, Management, and Culture

2008 ◽  
Keyword(s):  
Home Range ◽  
Maximum Distance ◽  
Home Ranges ◽  
High Fidelity ◽  
Lota Lota ◽  
Acoustic Tags ◽  
The Mean ◽  
General Movement ◽  
Kootenai River ◽  
Do So

Abstract.—Adult burbot <em>Lota lota </em>from Koocanusa Reservoir, Montana, USA were surgically implanted with acoustic (<em>n </em>= 28) and combined radio/acoustic tags (<em>n </em>= 12) to quantify movements and home range. Fish were tagged from November 2003 to April 2004, and tracking efforts were conducted approximately weekly during daylight hours on Koocanusa Reservoir using a motor boat during the period of mid-December 2003 to July 2005, which spanned two burbot spawning seasons. Six (15%) tagged burbot were never relocated after release, and an additional seven (17.5%) of the tagged burbot either died or shed their tag within 60 d after release. We relocated 34 marked burbot (85%) on at least three occasions (mean = 10.0). Burbot frequently used the deepest portions of the reservoir, especially during the summer months. We estimated that the mean 50%, 75%, and 90% kernel home ranges were 14.6, 22.6 and 32.3 km<sup>2</sup>, respectively. We found no evidence that burbot home range differed within the 2 years of this study. Although we did observe burbot moving a maximum distance of up to 64.3 km, we were unable to discern any general movement patterns by month or capture location. Individual burbot tagged in this study had relatively high fidelity to the original capture side of the reservoir, and almost half of our marked burbot were never relocated on the opposite side of the remnant Kootenai River thalweg, and those that did cross the thalweg do so infrequently. One burbot was entrained through Libby Dam approximately 134–276 d after capture and tagging.

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