847 research outputs found
Note: A miniature oscillating microbalance for sampling ice and volcanic ash from a small airborne platform
A lightweight and low power oscillating microbalance for in situ sampling of atmospheric ice and volcanic ash is described for airborne platforms. Using a freely exposed collecting wire fixed at only one end to a piezo transducer, the instrument collects airborne materials. Accumulated mass is determined from the change in natural frequency of the wire. The piezo transducer is used in a dual mode to both drive and detect the oscillation. Three independent frequency measurement techniques are implemented with an on-board microcontroller: a frequency sweep, a Fourier spectral method, and a phase-locked loop. These showed agreement to ±0.3 Hz for a 0.5 mm diameter collecting wire of 120 mm long, flown to 19 km altitude on a weather balloon. The instrument is well suited to disposable use with meteorological radiosondes, to provide high resolution vertical profiles of mass concentration
Confirmation of the classic tris(2,2Ì’-bipyridyl)ruthenium(II) and oxalate electrochemiluminescence mechanism using EPR spectroscopy
A chemically initiated adaptation of the classic [Ru(bipy) ]/oxalate electrochemiluminescence coreactant system has revealed the elusive radical intermediates of the light-producing pathway. Oxalyl (HCO) and hydroxyformyl (HCO) radicals have been captured on a quartz surface and characterised using EPR spectroscopy
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Note: A balloon-borne accelerometer technique for measuring atmospheric turbulence
A weather balloon and its suspended instrument package behave like a pendulum with a moving pivot. This dynamical system is exploited here for the detection of atmospheric turbulence. By adding an accelerometer to the instrument package, the size of the swings induced by atmospheric turbulence can be measured. In test flights, strong turbulence has induced accelerations greater than 5g, where g = 9.81 m s−2. Calibration of the accelerometer data with a vertically orientated lidar has allowed eddy dissipation rate values of between 10−3 and 10−2 m2 s−3 to be derived from the accelerometer data. The novel use of a whole weather balloon and its adapted instrument package can be used as a new instrument to make standardized in situ measurements of turbulence
Oppositional defiant disorder
Oppositional defiant disorder (ODD) is a disruptive behaviour disorder involving an ongoing pattern of angry/irritable mood, argumentative/defiant behaviour and vindictiveness. Onset is typically before 8 years of age, although ODD can be diagnosed in both children and adults. This disorder is associated with substantial social and economic burden, and childhood ODD is one of the most common precursors of other mental health problems that can arise across the lifespan. The population prevalence of ODD is ~3 to 5%. A higher prevalence in males than females has been reported, particularly before adolescence. No single risk factor accounts for ODD. The development of this disorder seems to arise from the interaction of genetic and environmental factors, and mechanisms embedded in social relationships are understood to contribute to its maintenance. The treatment of ODD is often successful, and relatively brief parenting interventions produce large sized treatment effects in early childhood. Accordingly, ODD represents an important focus for research, practice and policy concerning early intervention and prevention in mental health.</p
Oppositional defiant disorder
Oppositional defiant disorder (ODD) is a disruptive behaviour disorder involving an ongoing pattern of angry/irritable mood, argumentative/defiant behaviour and vindictiveness. Onset is typically before 8 years of age, although ODD can be diagnosed in both children and adults. This disorder is associated with substantial social and economic burden, and childhood ODD is one of the most common precursors of other mental health problems that can arise across the lifespan. The population prevalence of ODD is ~3 to 5%. A higher prevalence in males than females has been reported, particularly before adolescence. No single risk factor accounts for ODD. The development of this disorder seems to arise from the interaction of genetic and environmental factors, and mechanisms embedded in social relationships are understood to contribute to its maintenance. The treatment of ODD is often successful, and relatively brief parenting interventions produce large sized treatment effects in early childhood. Accordingly, ODD represents an important focus for research, practice and policy concerning early intervention and prevention in mental health.</p
Use of Lactic Acid Bacteria to Reduce Methane Production in Ruminants, a Critical Review
peer-reviewedEnteric fermentation in ruminants is the single largest anthropogenic source of
agricultural methane and has a significant role in global warming. Consequently,
innovative solutions to reduce methane emissions from livestock farming are required
to ensure future sustainable food production. One possible approach is the use of lactic
acid bacteria (LAB), Gram positive bacteria that produce lactic acid as a major end
product of carbohydrate fermentation. LAB are natural inhabitants of the intestinal tract
of mammals and are among the most important groups of microorganisms used in
food fermentations. LAB can be readily isolated from ruminant animals and are currently
used on-farm as direct-fed microbials (DFMs) and as silage inoculants. While it has been
proposed that LAB can be used to reduce methane production in ruminant livestock,
so far research has been limited, and convincing animal data to support the concept
are lacking. This review has critically evaluated the current literature and provided a
comprehensive analysis and summary of the potential use and mechanisms of LAB as
a methane mitigation strategy. It is clear that although there are some promising results,
more research is needed to identify whether the use of LAB can be an effective methane
mitigation option for ruminant livestock
Theoretical and conceptual issues around equity in healthcare: application to cervical cancer screening in South Australia
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