131 research outputs found
Census and ear-notching of black rhinos (Diceros bicornis michaeli) in Tsavo East National Park, Kenya
This paper updates the status of the black rhino population in Tsavo East National Park (NP). Data were acquired through aerial counts of the black rhino between 3 and 9 October 2010 using three fixed-wing husky aircrafts and a Bell 206L helicopter in an area of about 3,300 km2. Based on previous sightings of rhinos, the area was divided into 14 blocks, with each block subdivided into 400 m transects. An aircraft flying at about 500 m above the ground was assigned to carry out the aerial survey following these transects within each block. Observers scanned for rhinos about 200 m on either sides of the flight paths. Intensive searches in areas with dense vegetation, especially along the Galana and Voi Rivers and other known rhino range areas was also carried out by both the huskies and the helicopter. The count resulted in sighting of 11 black rhinos. Seven of these individuals were ear notched and fitted with radio transmitters and the horns were tipped off to discourage poaching. Three of the seven captured rhinos were among the 49 animals translocated to Tsavo East between 1993 and 1999. The other four animals were born in Tsavo East. Two female rhinos and their calves were not ear-notched or fitted with transmitters. It is recommended that another count be carried out immediately after the wet season as the rhinos spend more time in the open areas while the vegetation is still green. The repeat aerail count is to include blocks north of River Galana
Сіверські князі Наримунтовичі
У статті досліджується генеалогія та діяльність сіверських Наримунтовичів – однієї з гілок литовсько-руської династії Гедиміновичів, представники якої наприкінці XIV – початку XV ст. володіли кількома удільними князівствами у Сіверській землі.В статье исследуется генеалогия и деятельность северских Наримунтовичей – одной из ветвей литовско-русской династии Гедиминовичей, представители которой в конце XIV – начале XV вв. владели несколькими удельными княжествами в Северской земле.The article deals with genealogy and activity of the seversky Narimuntoviches as one of branches of the Lithuanian-Russian dynasty of the Gediminoviches, representatives of which at the end XIV – beginning of XV centuries owned some specific principalities in the Seversky land
Complex hydrides for energy storage
In the past decades, complex hydrides and complex hydrides-based materials have been thoroughly investigated as materials for energy storage, owing to their very high gravimetric and volumetric hydrogen capacities and interesting cation and hydrogen diffusion properties. Concerning hydrogen storage, the main limitations of this class of materials are the high working temperatures and pressures, the low hydrogen absorption and desorption rates and the poor cyclability. In the past years, research in this field has been focused on understanding the hydrogen release and uptake mechanism of the pristine and catalyzed materials and on the characterization of the thermodynamic aspects, in order to rationally choose the composition and the stoichiometry of the systems in terms of hydrogen active phases and catalysts/destabilizing agents. Moreover, new materials have been discovered and characterized in an attempt to find systems with properties suitable for practical on-board and stationary applications. A significant part of this rich and productive activity has been performed by the research groups led by the Experts of the International Energy Agreement Task 32, often in collaborative research projects. The most recent findings of these joint activities and other noteworthy recent results in the field are reported in this paper
MgH2 nanoparticles confined in reduced graphene oxide pillared with organosilica: a novel type of hydrogen storage material
Hydrogen is a promising energy carrier that can push forward the energy
transition because of its high energy density (142 MJ kg-1), variety of
potential sources, low weight and low environmental impact, but its storage for
automotive applications remains a formidable challenge. MgH2, with its high
gravimetric and volumetric density, presents a compelling platform for hydrogen
storage; however, its utilization is hindered by the sluggish kinetics of
hydrogen uptake/release and high temperature operation. Herein we show that a
novel layered heterostructure of reduced graphene oxide and organosilica with
high specific surface area and narrow pore size distribution can serve as a
scaffold to host MgH2 nanoparticles with a narrow diameter distribution around
~2.5 nm and superior hydrogen storage properties to bulk MgH2. Desorption
studies showed that hydrogen release starts at 50 {\deg}C, with a maximum at
348 {\deg}C and kinetics dependent on particle size. Reversibility tests
demonstrated that the dehydrogenation kinetics and re-hydrogenation capacity of
the system remains stable at 1.62 wt.% over four cycles at 200 {\deg}C. Our
results prove that MgH2 confinement in a nanoporous scaffold is an efficient
way to constrain the size of the hydride particles, avoid aggregation and
improve kinetics for hydrogen release and recharging
Історико-правові аспекти інформаційного протиборства в умовах воєнного стану (1941 – 1942 рр.)
Щодо впливу на людину засобів інформаційно-пропагандистської зброї.О влиянии на человека средств информационно-пропагандистского оружия.On influence of the methods of informative propagandistic weapon on the human
Corrigendum: Three spatially separate records confirm the presence of and provide a range extension for the giant pangolin Smutsia gigantea in Kenya (Oryx (2022) DOI: 10.1017/S0030605322000126)
In the original publication of this article, the list of authors was incomplete, with only the following authors listed: Tommy Sandri, Claire Okell, Stuart Nixon, Naomi Matthews, Fred Omengo, James Mathenge, Stephen Ndambuki, Daniel W.S. Challender and Bradley Cain. The correct author list is: Tommy Sandri, Claire Okell, Stuart Nixon, Naomi Matthews, Fred Omengo, James Mathenge, Stephen Ndambuki, Daniel W.S. Challender, Richard Chepkwony, Patrick Omondi, Shadrack Ngene and Bradley Cain The article has been updated to include the correct author details and add the ORCID iD of Shadrack Ngene
Comparison of efavirenz levels in blood and hair with pharmacy refills as measures of adherence and predictors of viral suppression among people living with HIV in Nigeria
BackgroundStrategies to support adherence are constrained by the lack of tools to objectively monitor medication intake in low-resource settings. Pharmacologic measures are objective, but pharmacy refill data is more accessible and cost-efficient. This study compared short-term and long-term efavirenz (EFV) drug levels with pharmacy refill adherence data (PRA) and evaluated their ability to predict viral suppression among people living with HIV in Nigeria.MethodsPaired hair and dried blood spot (DBS) samples were obtained from 91 adults living with HIV receiving 600 mg EFV-based antiretroviral therapy (ART) and EFV concentrations were measured via validated methods using liquid-chromatography-mass-spectrometry. PRA was estimated from pharmacy records, based on the number of days a patient collected medication before or after the scheduled pick-up date. PRA was categorized into ≤ 74%, 75-94% and ≥ 95%, defined as poor, medium and high adherence, respectively. HIV viral loads closest to the hair sampling time (within 6 months) were also abstracted. Receiver Operating Characteristics (ROC) curve analyses compared the ability of adherence metrics to predict viral suppression.ResultsBased on PRA, 81% of participants had high adherence while 11% and 8% had medium and poor adherence, respectively. The median (IQR) EFV concentrations were 6.85 ng/mg (4.56-10.93) for hair and 1495.6 ng/ml (1050.7-2365.8) for DBS. Of the three measures of adherence, hair EFV concentration had the highest Area Under Curve (AUC) to predict viral suppression. Correlations between EFV concentrations in DBS and hair with PRA were positive (r = 0.12, P = 0.27 and r = 0.21, P = 0.05, respectively) but not strong.ConclusionsEFV concentrations in hair were the strongest predictor of viral suppression and only weakly correlated with pharmacy refill adherence data in Nigeria. This study suggests that resource-limited settings may benefit from objective adherence metrics to monitor and support adherence
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