Foraging behaviour of a blue banded bee, Amegilla chlorocyanea in greenhouses: implications for use as tomato pollinators

© INRA, DIB-AGIB, EDP Sciences 2007Blue-banded bees (Amegilla spp.) are Australian native buzz pollinators that are a promising alternative to the introduction of the bumblebee (Bombus terrestris) for use as pollinators of tomatoes in Australian greenhouses. The foraging behaviour of Amegilla chlorocyanea under greenhouse conditions was monitored in detail. Our results showed that female Amegilla are active foragers that make on average 9 pollen foraging flights per day. Using data about flower visitation, we estimated the number of actively nesting female bees needed for adequate pollination in a commercial greenhouse as 282 per hectare.Katja Hogendoorn, Steven Coventry and Michael Anthony Kelle

Stabilisation of BGK modes by relativistic effects

Context. We examine plasma thermalisation processes in the foreshock region of astrophysical shocks within a fully kinetic and self-consistent treatment. We concentrate on proton beam driven electrostatic processes, which are thought to play a key role in the beam relaxation and the particle acceleration. Our results have implications for the effectiveness of electron surfing acceleration and the creation of the required energetic seed population for first order Fermi acceleration at the shock front. Aims. We investigate the acceleration of electrons via their interaction with electrostatic waves, driven by the relativistic Buneman instability, in a system dominated by counter-propagating proton beams. Methods. We adopt a kinetic Vlasov-Poisson description of the plasma on a fixed Eulerian grid and observe the growth and saturation of electrostatic waves for a range of proton beam velocities, from 0.15c to 0.9c. Results. We can report a reduced stability of the electrostatic wave (ESW) with increasing non-relativistic beam velocities and an improved wave stability for increasing relativistic beam velocities, both in accordance with previous findings. At the highest beam speeds, we find the system to be stable again for a period of ≈160 plasma periods. Furthermore, the high phase space resolution of the Eulerian Vlasov approach reveals processes that could not be seen previously with PIC simulations. We observe a, to our knowledge, previously unreported secondary electron acceleration mechanism at low beam speeds. We believe that it is the result of parametric couplings to produce high phase velocity ESW’s which then trap electrons, accelerating them to higher energies. This allows electrons in our simulation study to achieve the injection energy required for Fermi acceleration, for beam speeds as low as 0.15c in unmagnetised plasma

Axillary Brachial Plexus Block

The axillary approach to brachial plexus blockade provides satisfactory anaesthesia for elbow, forearm, and hand surgery and also provides reliable cutaneous anaesthesia of the inner upper arm including the medial cutaneous nerve of arm and intercostobrachial nerve, areas often missed with other approaches. In addition, the axillary approach remains the safest of the four main options, as it does not risk blockade of the phrenic nerve, nor does it have the potential to cause pneumothorax, making it an ideal option for day case surgery. Historically, single-injection techniques have not provided reliable blockade in the musculocutaneous and radial nerve territories, but success rates have greatly improved with multiple-injection techniques whether using nerve stimulation or ultrasound guidance. Complete, reliable, rapid, and safe blockade of the arm is now achievable, and the paper summarizes the current position with particular reference to ultrasound guidance

Risk Management Strategies by Australian Farmers

Australian farmers operate in one of the most risky environment in the world. They have to cope with various sources of risk in their businesses. This paper reports results of two case studies undertaken to examine the issues of farming risks and risk management strategies in Australia. The first case study found that climate variability, financial risk, marketing risk, and personal risk were regarded as the major sources of farming risk in the Upper Eyre Peninsula of South Australia. The main management strategies used by farmers included diversifying varieties, minimising tillage, minimising area of risky crops and maximising area of the least-risky crop, having high equity, having farm management deposits and other off-farm investments, and "leaving marketing to experts". The second case study revealed that climate variability was ranked as the most important source of farming risk in southwest Queensland. This was then followed by financial risks, government policy, and marketing risks. The main management strategies used were enterprise diversification (having predominantly cattle and farming cash crops), conserving moisture, using zero till planting, diversified sales (selling only part of the farm's production at any one time), and having off-farm investments. The paper then attempts to reconcile the two case studies by comparing the results with studies from the United States of America, Canada, Netherlands, and New Zealand.risk, risk management, strategies, farmers, Australia, Farm Management, Risk and Uncertainty,

Improving evaluation of the distribution and density of immunostained cells in breast cancer using computerized video image analysis

Quantitation of cell density in tissues has proven problematic over the years. The manual microscopic methodology, where an investigator visually samples multiple areas within slides of tissue sections, has long remained the basic ‘standard’ for many studies and for routine histopathologic reporting. Nevertheless, novel techniques that may provide a more standardized approach to quantitation of cells in tissue sections have been made possible by computerized video image analysis methods over recent years. The present study describes a novel, computer-assisted video image analysis method of quantitating immunostained cells within tissue sections, providing continuous graphical data. This technique enables the measurement of both distribution and density of cells within tissue sections. Specifically, the study considered immunoperoxidase-stained tumor infiltrating lymphocytes within breast tumor specimens, using the number of immunostained pixels within tissue sections to determine cellular density and number. Comparison was made between standard manual graded quantitation methods and video image analysis, using the same tissue sections. The study demonstrates that video image techniques and computer analysis can provide continuous data on cell density and number in immunostained tissue sections, which compares favorably with standard visual quantitation methods, and may offer an alternative

Isolated limb infusion chemotherapy for melanoma: an overview of early experience at the Adelaide Melanoma Unit

Background: Isolated limb infusion (ILI) using cytotoxic agents has been demonstrated to be an effective and less invasive alternative modality than isolated limb perfusion for the treatment of melanoma localized to a limb. Percutaneous catheters were inserted into the axial artery and vein of the affected limb while using a pneumatic cuff to restrict limb vascular flow proximally to "isolate" the limb from the body and enable delivery of high-dose intra-arterial chemotherapy selectively to the limb. The ILI technique was developed at the Sydney Melanoma Unit (now renamed the Melanoma Institute Australia), and only a few other centers have reported separate results. We report our early results using the ILI technique for management of locally recurrent surgically nonresectable melanoma. Methods and results: Twenty-eight ILI procedures were performed in 20 patients treated with one or more procedures between 1997 and 2007. Patient parameters and clinical responses were evaluated. The median follow-up duration was 15.9 months after the first ILI, with an overall response rate after one or more infusions of 70%, of which 35% were complete responders and 35% were partial responders, with a further 20% showing stable disease, giving a "clinically significant" response rate of 90%. After one ILI (n = 20), the overall response rate was 70%, with 20% complete responders and 50% partial responders, and 20% with stable disease. Low limb toxicities were generally observed, and no amputations were required. Conclusion: ILI chemotherapy is a useful technique, which can be readily repeated for control of melanoma in the limb. It is generally well tolerated, and is capable of achieving a cure, delayed progression, or effective palliation in selected cases. The longest survivors in this series were 8 and 10 years from the last ILI.Mitchell H Giles, Brendon J Coventr

The 20th anniversary of interleukin-2 therapy: Bimodal role explaining longstanding random induction of complete clinical responses

Background: This year marks the twentieth anniversary of the approval by the US Food and Drug Administration of interleukin-2 (IL2) for use in cancer therapy, initially for renal cell carcinoma and later for melanoma. IL2 therapy for cancer has stood the test of time, with continued widespread use in Europe, parts of Asia, and the US. Clinical complete responses are variably reported at 5%–20% for advanced malignant melanoma and renal cell carcinoma, with strong durable responses and sustained long-term 5–10-year survival being typical if complete responses are generated. Methods: The literature was reviewed for the actions and clinical effects of IL2 on subsets of T cells. The influence of IL2 on clinical efficacy was also sought. Results: The review revealed that IL2 is capable of stimulating different populations of T cells in humans to induce either T effector or T regulatory responses. This apparent "functional paradox" has confounded a clear understanding of the mechanisms behind the clinical effects that are observed during and following administration of IL2 therapy. An average complete response rate of around 7% in small and large clinical trials using IL2 for advanced renal cell carcinoma and malignant melanoma has been shown from a recent review of the literature. Conclusion: This review considers the published literature concerning the actions and emerging clinical effects of IL2 therapy, spanning its 20-year period in clinical use. It further details some of the recently described "bimodal" effects of IL2 to explain the apparent functional paradox, and how IL2 might be harnessed to emerge rapidly as a much more effective and predictable clinical agent in the near future.Brendon J Coventry, Martin L Ashdow

Markers of success: A study of twins' instructed second language acquisition

We examined the association between proficiency in instructed second language acquisition (ISLA) and previous bilingualism, starting age of ISLA, language anxiety and attitude. The analyses were conducted on 564 adolescent Australian twins. Additionally, by examining discrepancies within approximately 100 pairs of monozygotic twins, we sought to specifically identify the environmental effects related to attitude and anxiety on achievement (i.e. with genetic effects removed). We found a clear relationship between attitude towards language learning and proficiency in the second language. Furthermore, the analyses on the monozygotic twins point to the possibility that higher language anxiety is associated with higher proficiency. On the other hand, bilingualism and starting age of ISLA appear to be unrelated to proficiency in the language being learned.</p