Diurnal activity patterns, habitat use and foraging habits of Egyptian goose (Alopochena egyptiacus Linnaeus, 1766) in the Boyo wetland, southern Ethiopia

Egyptian goose (Alopochena egyptiacus) is a resident bird species in Africa South of the Sahara occurring throughout the entire Nile Valley. Despite the wide distribution, the available information on its behavioral ecology is limited in Ethiopia. A study on the activity patterns, habitat use and foraging  habits  of Egyptian goose was carried out in and around Boyo wetland, Ethiopia, during the dry and wet seasons. Scan sampling method was used to study the activity patterns and habitat use of Egyptian goose in  grassland, mudflat and shallow water habitats of the wetland. The feeding behavior of Egyptian goose was also observed in the surrounding farmland habitats using scan sampling method.  Generally,  Egyptian geese spent most of their time resting (39.81%) followed by foraging (32.64%). They spent 10.43% of their time in comfort movement preening or stretching. The rest of their time was allocated for locomotion (6.63%), vigilance (5.75%), and social behavior (1.59%), and other activities (2.86%). Most of the birds were engaged in foraging activity in the morning (07:00-9:00 h) and afternoon (16:00 - 18:00 h) hours both during the wet and dry seasons.  About 39% of Egyptian geese were scanned in mudflat, 31.5% in grassland, and 30.05% in shallow water habitats engaged in different activities. Most individuals  used the grassland habitat for foraging during the dry (59.5%) and wet (74%) seasons, while they used shallow water and mudflat habitats for resting both during the wet and dry seasons seasons. The birds were observed foraging  mainly  grass during the dry (93.62%) and wet (59.52%) seasons. The Egyptian geese show diurnal activity pattern with feeding peaks in early morning and late afternoon hours as is observed in many other avian taxa. The Boyo wetland is also as an important foraging ground for this species and other birds in the area. Further ecological studies on the species and impact of human activities on the Boyo wetland should be conducted for the conservation of the avifauna

The Toxicity of plant material, Drimia Altissima (Urginea Altissima), Against the Field Rat, Arvicanthis Abyssinicus: A potential non-synthetic rodenticide

Background: Rodents are important pests of public health and agricultural importance, capable of transmitting diseases to humans and causing crop damage. The present rodent control strategy depends primarily on synthetic rodenticides, which are highly toxic, affect non-target species, and are expensive. Naturally produced organic pesticides may be more desirable as they are less toxic to non-target animals and are  economically sustainable.Objective: The objective of the study is to explore the toxicity and palatability of the bulbs of Drimia altissima against the field rat, Arvicanthis abyssincus with the aim of developing locally based organic rodenticides.Method: This is a laboratory study for evaluating the toxicity of D. altissimia bait against the field rat, Arvicanthis abyssincus. In the study, field rats were randomly assigned to treatment and control groups. The treatment groups received different concentrations of D. altissimia poison bait prepared in the lab. The control groups received the plain bait. Mortality was recorded during the test period.Results: Of the treatment groups, 80%-100% of the rats receiving the poison bait died, while none of the rats offered a choice between the plain bait and the poisoned bait died. It is estimated that 8% of the powdered bulb would produce 50% mortality.Conclusion: The powdered bulb of D. altissima resulted in rat mortality in the test but not in the control group. The liberation of the toxic substance from the poisoned bait might have been slowed by the presence of the plain bait in the choice test. The result of this study suggests that further work is needed for understanding the toxicological properties of the active agents in the bulb

Secondary charging effects due to icy dust particle impacts on rocket payloads

We report measurements of dust currents obtained with a small probe and a larger probe during the flight of the ECOMA-4 rocket through the summer polar mesosphere. The payload included two small dust probes behind a larger dust probe located centrally at the front. For certain phases of the payload rotation, the current registered by one of the small dust probes was up to 2 times the current measured with the larger probe, even though the effective collection area of the larger probe was 4 times that of the small one. We analyze the phase dependence of the currents and their difference with a model based on the assumption that the small probe was hit by charged dust fragments produced in collisions of mesospheric dust with the payload body. Our results confirm earlier findings that secondary charge production in the collision of a noctilucent cloud/Polar Summer Mesospheric Echo (NLC/PMSE) dust particle with the payload body must be several orders of magnitude larger than might be expected from laboratory studies of collisions of pure ice particles with a variety of clean surfaces. An important consequence is that for some payload configurations, one should not assume that the current measured with a detector used to study mesospheric dust is simply proportional to the number density of ambient dust particles. The higher secondary charge production may be due to the NLC/PMSE particles containing multiple meteoric smoke particles

A comparison of the neuroprotective efficacy of newly developed oximes (K117, K127) and currently available oxime (obidoxime) in tabun-poisoned rats

The potency of newly developed bispyridinium compounds (K117, K127) to reduce tabun-induced acute neurotoxic signs and symptoms was compared with currently available oxime (obidoxime) using functional observational battery. The neuroprotective effects of atropine alone and atropine combined with one of three bispyridinium oximes (K117, K127, obidoxime) on rats poisoned with tabun at a sublethal dose (180 μg/kg i.m.; 80% of LD50 value) were studied. Tabun-induced neurotoxicity was monitored using a functional observational battery and automatic measurement of motor activity at 24 h following tabun challenge. The results indicated that all tested oximes combined with atropine enabled tabun-poisoned rats to survive 24 h following tabun challenge while one tabun-poisoned rats died within 24 h after tabun poisoning when the rats were treated with atropine alone. Newly developed oxime K127 combined with atropine was the most effective in decreasing tabun-induced neurotoxicity in the case of sublethal poisonings among all oximes tested. Nevertheless, the differences of neuroprotective efficacy between K127 and obidoxime are not sufficient to replace obidoxime by K127 for the treatment of acute tabun poisonings

On modeling and measuring viscoelasticity with dynamic Atomic Force Microscopy

The interaction between a rapidly oscillating atomic force microscope tip and a soft material surface is described using both elastic and viscous forces with a moving surface model. We derive the simplest form of this model, motivating it as a way to capture the impact dynamics of the tip and sample with an interaction consisting of two components: interfacial or surface force, and bulk or volumetric force. Analytic solutions to the piece-wise linear model identify characteristic time constants, providing a physical explanation of the hysteresis observed in the measured dynamic force quadrature curves. Numerical simulation is used to fit the model to experimental data and excellent agreement is found with a variety of different samples. The model parameters form a dimensionless impact-rheology factor, giving a quantitative physical number to characterize a viscoelastic surface that does not depend on the tip shape or cantilever frequency.Comment: 13 pages, 7 figure

A- and D-optimal row-column designs for two-colour cDNA microarray experiments using linear mixed effects models

Microarray experiments help scientists to study the expression level of thousands of genes simultaneously. These experiments have many design challenges, such as, for example, whichmRNA samples should be co-hybridized together and which treatments should be labelled with which fluorescent dye. Therefore a carefully designed microarray experiment to obtain efficient and reliable data so as to ensure the precise estimate of comparisons of interest is required. The present paper is concerned with A- and D-optimal row-column designs for two-colour microarray experiments, with the array and dye effects treated as the column and row effects, respectively. Linear mixed effects models were used to describe experiments for which a comparison of all possible pairs of treatments is of particular interest by taking the arrays as random column effects. The results of this study show that the optimal row-column designs under the linear fixed effects model are not necessarily optimal under the linear mixed effects model setting