Further experiements on the control of early blight or target spot of potatoes

The effective control of Potato Early Blight or Target Spot by the use of Zineb fungicide (used in the proprietary form Dithane Z.78) has previously been reported in this Journal. It was shown in preliminary spray trials that the foliage blight caused by this disease is very destructive, and by the application of four Dithane sprays yields were increased in the order of 30 per cent., equivalent to approximately four tons per acre. Further experiments have now been conducted and the results indicate that even two applications of Dithane spray may, under conditions of severe blight attack, promote worthwhile higher yields

Plant disease - early blight or target spot of potatoes

Early blight or target spot caused by the fungus Alternaria solani is a widespread disease of potatoes which in Western Australia is most prevalent in crops dug in autumn and early summer. The disease may attack both foliage and tubers, but the tuber rot phase of the disease has hitherto caused most concern to local growers because it causes obvious losses in storage. The less obvious but more serious effects of the foliage blight have generally been overlooked, chiefly because the disease usually develops late in the season when the crops are approaching maturity. However recent spray trials with new fungicides have clearly demonstrated that the destructiveness of the foliage attack has been greatly underestimated, for it may cause considerable reduction in yield

AMPK and TOR:the Yin and Yang of cellular nutrient sensing and growth control

The AMPK (AMP-activated protein kinase) and TOR (target-of-rapamycin) pathways are interlinked, opposing signaling pathways involved in sensing availability of nutrients and energy and regulation of cell growth. AMPK (Yin, or the "dark side") is switched on by lack of energy or nutrients and inhibits cell growth, while TOR (Yang, or the "bright side") is switched on by nutrient availability and promotes cell growth. Genes encoding the AMPK and TOR complexes are found in almost all eukaryotes, suggesting that these pathways arose very early during eukaryotic evolution. During the development of multicellularity, an additional tier of cell-extrinsic growth control arose that is mediated by growth factors, but these often act by modulating nutrient uptake so that AMPK and TOR remain the underlying regulators of cellular growth control. In this review, we discuss the evolution, structure, and regulation of the AMPK and TOR pathways and the complex mechanisms by which they interact

The use of hand-held computers (PDAs) to audit and validate eradication of a post-border detection of Khapra Beetle, Trogoderma granarium, in Western Australia

Most of Australia’s agricultural produce is exported. Demonstrating freedom from certain plant and animal pests and diseases is critical to securing and maintaining market access. Surveillance is an important tool in gaining market access and accordingly exporting countries now need to provide accurate, credible evidence to confirm pest freedom status.In the past nearly all field-collected surveillance information was recorded manually to paper reducing the rate of capture, integrity, conformity as well as security of the data. This paper describes the development of pest surveillance data collection software and hardware using PDAs (Personal Digital Assistants) to provide auditing, validation, chain of evidence and increase the volume of data collected as well as its integrity through relational databases and seamless data transfer to corporate systems. The system’s first deployment was during a T. granarium eradication. The khapra beetle (Trogoderma granarium) is one of the most serious pests of stored grain and is a regulated quarantine pest in most countries around the world. In April 2007, there was a post-border detection of T. granarium larvae and adults in a Western Australian residence. Immediate and uncompromising action was taken to quarantine the home and fumigate it with methyl-bromide at an internationally established rate known to control T. granarium (AQIS T9056). A two-year T. granarium trapping program was undertaken which used PDA software to provide evidence of complete eradication via 1273 trap inspections. This achievement was supported by GPSlocated traps, digital voice navigation itineraries, digital time and date stamps, field printed barcode labels, site imagery, all in a single hand-held unit. Keywords: T. granarium, Khapra beetle, Eradication, Biosecurity, PDA, Surveillanc

Electrical coupling of neuro-ommatidial photoreceptor cells in the blowfly

A new method of microstimulation of the blowfly eye using corneal neutralization was applied to the 6 peripheral photoreceptor cells (R1-R6) connected to one neuro-ommatidium (and thus looking into the same direction), whilst the receptor potential of a dark-adapted photoreceptor cell was recorded by means of an intracellular microelectrode. Stimulation of the photoreceptor cells not impaled elicited responses in the recorded cell of about 20% of the response elicited when stimulating the recorded cell. This is probably caused by gap junctions recently found between the axon terminals of these cells. Stimulation of all 6 cells together yielded responses that were larger and longer than those obtained with stimulation of just the recorded cell, and intensity-response curves that deviated more strongly from linearity. Evidence is presented that the resistance of the axon terminal of the photoreceptor cells quickly drops in response to a light flash, depending on the light intensity. Incorporating the cable properties of the cell body and the axon, the resistance of the gap junctions, and the (adapting) terminal resistance, a theoretical model is presented that explains the measurements well. Finally, it is argued that the gap junctions between the photoreceptor cells may effectively uncouple the synaptic responses of the cells by counteracting the influence of field potentials.

Surprising variations in the rotation of the chemically peculiar stars CU Virginis and V901 Orionis

CU Vir and V901 Ori belong among these few magnetic chemically peculiar stars whose rotation periods vary on timescales of decades. We aim to study the stability of the periods in CU Vir and V901 Ori using all accessible observational data containing phase information. We collected all available relevant archived observations supplemented with our new measurements of these stars and analysed the period variations of the stars using a novel method that allows for the combination of data of diverse sorts. We found that the shapes of their phase curves were constant, while the periods were changing. Both stars exhibit alternating intervals of rotational braking and acceleration. The rotation period of CU Vir was gradually shortening until the year 1968, when it reached its local minimum of 0.52067198 d. The period then started increasing, reaching its local maximum of 0.5207163 d in the year 2005. Since that time the rotation has begun to accelerate again. We also found much smaller period changes in CU Vir on a timescale of several years. The rotation period of V901 Ori was increasing for the past quarter-century, reaching a maximum of 1.538771 d in the year 2003, when the rotation period began to decrease. A theoretically unexpected alternating variability of rotation periods in these stars would remove the spin-down time paradox and brings a new insight into structure and evolution of magnetic upper-main-sequence stars.Comment: 5 pages, 3 figure

A semi-classical over-barrier model for charge exchange between highly charged ions and one-optical electron atoms

Absolute total cross sections for electron capture between slow, highly charged ions and alkali targets have been recently measured. It is found that these cross sections follow a scaling law with the projectile charge which is different from the one previously proposed basing on a classical over-barrier model (OBM) and verified using rare gases and molecules as targets. In this paper we develop a "semi-classical" (i.e. including some quantal features) OBM attempting to recover experimental results. The method is then applied to ion-hydrogen collisions and compared with the result of a sophisticated quantum-mechanical calculation. In the former case the accordance is very good, while in the latter one no so satisfactory results are found. A qualitative explanation for the discrepancies is attempted.Comment: RevTeX, uses epsf; 6 pages text + 3 EPS figures Journal of Physics B (scehduled March 2000). This revision corrects fig.

Outdoor Mental Health Interventions and Outdoor Therapy: A statement of good practice

Health, well-being and self-development has been a cornerstone of the impact and value of outdoor learning practices for many decades. Over recent years, we have seen an exponential growth in therapeutic outdoor initiatives and programmes being developed and utilised for mental health and well-being benefits. Traditional terms such as adventure therapy, wilderness therapy, nature therapy and outdoor counselling, have more recently been joined with a plethora of wider terms, such as eco-therapy, forest bathing, and a Natural Health Service, to name a few. All of these terms are taking claim to some kind of health benefit (physical or psychological) for getting outdoors. This Institute for Outdoor Learning (IOL) statement purposefully sets out a view on competence when combining mental health and well-being interventions with outdoor learning: o The primary goal was to develop a model that could support organisations and individuals who provide and utilise services for mental health and well-being in an outdoor setting. The statement has been strongly informed by mapping current practice in the UK. o It has been created to ensure that those engaging outdoor learning services to improve mental health and well-being can do so with confidence and trust in what they are offered