bluuebunny/crossref_metadata_2025 huggingface dataset:
Ozone generation by negative direct current corona discharges in dry air fed coaxial wire-cylinder reactors
Authors: Yehia Ashraf , Mizuno Akira
Published: May 2013

An analytical study was made in this paper for calculating the ozone generation by negative dc corona discharges. The corona discharges were formed in a coaxial wire-cylinder reactor. The reactor was fed by dry air flowing with constant rates at atmospheric pressure and room temperature, and stressed by a negative dc voltage. The current-voltage characteristics of the negative dc corona discharges formed inside the reactor were measured in parallel with concentration of the generated ozone under different operating conditions. An empirical equation was derived from the experimental results for calculating the ozone concentration generated inside the reactor. The results, that have been recalculated by using the derived equation, have agreed with the experimental results over the whole range of the investigated parameters, except in the saturation range for the ozone concentration. Therefore, the derived equation represents a suitable criterion for expecting the ozone concentration generated by negative dc corona discharges in dry air fed coaxial wire-cylinder reactors under any operating conditions in range of the investigated parameters.
Electronic and elastic properties of yttrium gallium garnet under pressure from ab initio studies
Authors: Monteseguro V. , Rodríguez-Hernández P. , Lavín V. , Manjón F. J. , Muñoz A.
Published: May 2013

In this paper, we present an ab initio study within the framework of density functional theory employing the generalized gradient approximation applied to the study of the structural, elastic, and electronic properties of yttrium gallium garnet, Y3Ga5O12, under hydrostatic pressure. The calculated structural ground state properties are in good agreement with the available experimental data. Pressure dependence of the elastic constants and the mechanical stability are analysed up to 90 GPa, showing that the garnet is mechanically unstable above 84 GPa. We also present the electronic band structure calculations which show that upon compression the fundamental direct gap first increases up to 63 GPa and later monotonically decreases under pressure.
Growing string method with interpolation and optimization in internal coordinates: Method and examples
Authors: Zimmerman Paul M.
Published: May 2013

The growing string method (GSM) has proven especially useful for locating chemical reaction paths at low computational cost. While many string methods use Cartesian coordinates, these methods can be substantially improved by changes in the coordinate system used for interpolation and optimization steps. The quality of the interpolation scheme is especially important because it determines how close the initial path is to the optimized reaction path, and this strongly affects the rate of convergence. In this article, a detailed description of the generation of internal coordinates (ICs) suitable for use in GSM as reactive tangents and in string optimization is given. Convergence of reaction paths is smooth because the IC tangent and orthogonal directions are better representations of chemical bonding compared to Cartesian coordinates. This is not only important quantitatively for reducing computational cost but also allows reaction paths to be described with smoothly varying chemically relevant coordinates. Benchmark computations with challenging reactions are compared to previous versions of GSM and show significant speedups. Finally, a climbing image scheme is included to improve the quality of the transition state approximation, ensuring high reliability of the method.
Enhanced magnetoresistance in graphene nanostructure modulated by effective exchange field and Fermi velocity
Authors: Liu Zheng-Fang , Wu Qing-Ping , Xiao Xian-Bo , Liu Nian-Hua
Published: May 2013

We investigate the spin-dependent transport properties of graphene nanostructures modulated by effective exchange field and Fermi velocity. The Brewster-like angle of spin transport becomes large and the spin-precession length becomes short with a decrease of the Fermi velocity in effective exchange field region. As a consequence, the magnetoresistance is enhanced remarkably and the number of the magnetoresistance dips increases. In the graphene-based periodic velocity barrier with the modulations of the electrostatic potential and the effective exchange field, the maximum of the magnetoresistance dips is a number of times larger than that of zero electrostatic potential.
A biased probe analysis of potential well formation in an electron only, low beta Polywell magnetic field
Authors: Carr Matthew , Khachan Joe
Published: May 2013

Orbital limited motion theory has been applied to two biased probes in a low beta Polywell. The cases studied include electron injection, magnetic field scaling, Polywell bias scaling, and radial position profiles. Langmuir's original orbital limited motion results for a monoenergetic electron beam are shown to be in excellent agreement for electron injection into the Polywell. A distribution function is proposed for the electron plasma characteristics in the centre of the magnetic null and confirmed with experimental results. A translational stage was used to measure the radial plasma potential profile. In other experiments, two probes were used to simultaneously measure the profiles in both the null and a position halfway along a corner cusp. The results confirm a radial potential well created by electron trapping in the device. In addition, we present preliminary results of the potential well scaling with the magnetic field, Polywell bias voltage, and the injected beam current. The electron population was found to maintain non-equilibrium in all cases studied.
Probing of molecular adsorbates on Au surfaces with large-amplitude temperature jumps
Authors: Berg Christopher M. , Lagutchev Alexei , Dlott Dana D.
Published: May 2013

Methods are described to probe vibrational transitions of molecules adsorbed on Au films subjected to calibrated ultrafast large-amplitude temperature jumps (T-jumps). The probe technique, vibrational sum-frequency generation (SFG), can monitor vibrations localized on specific parts of adsorbate molecules in the form of self-assembled monolayers (SAMs). Substrates had a thin Cr adhesion layer and an Au film that could withstand millions of T-jumps without laser damage of film or adsorbate. The substrate flash-heating process was characterized using ultrafast reflectance measurements. Reflectance transients induced by both 800 nm or 400 nm femtosecond pulses had overshoot-decay-plateau structures. The overshoots and decays represented optically generated hot electrons, and the plateaus gave the equilibrium temperature increase ΔT, which was in the 30–175 K range. The combination of SFG adsorbate and Au surface reflectance measurements was used to assess the effects of adsorbate vibrational heating by both hot electrons and the hot Au lattice. Two types of SAMs were investigated, nitrobenzenethiolate (NBT), where SFG probed nitro groups located 4 carbon atoms from the surface, and octadecylthiolate (ODT), where SFG probed terminal methyl groups 17 carbon atoms from the surface. With ΔT = 175 K, the NBT nitro transition νs(NO2) showed time-dependent intensity loss, redshifting, and broadening. These three kinds of transients also had overshoot-decay-plateau structures, which resulted from the interplay of hot electron excitation of higher-frequency vibrations including the probed vibration, and Au lattice heating of lower-energy vibrations and the conformational modes that cause reversible disordering of the SAM structure. The relative importance of these effects was different for the overshoot and plateau regions, and for the intensity, redshifting, and broadening effects. With ODT, T-jumps caused the terminal methyl groups to become disordered, and the disordering process was nonexponential in time. From the ratio of symmetric to antisymmetric CH-stretching intensities, the ensemble-averaged methyl tilt angle could be determined. With smaller T-jumps, the methyl groups gradually increased their tilt by a small amount during ∼200 ps, while with larger T-jumps where ΔT = 175 K, the methyl groups abruptly reoriented toward the surface normal and then tilted gradually away from the normal in the next 20 ps.
Atmospheric pressure plasma jet—Living tissue interface: Electrical, optical, and spectral characterization
Authors: Vasile Nastuta Andrei , Pohoata Valentin , Topala Ionut
Published: May 2013

The atmospheric pressure plasma jet is studied as potential plasma source for medical applications in direct contact with living tissues. Plasma bullets are generated in the region of the high voltage electrode and propagate towards the tissue surface. The presence of a localized plasma structure on tissues, played here by a human fingertip, is experimentally revealed. It was found that this plasma structure is sustained by a current flowing through the tissue, with the magnitude dependent on the distance from the discharge tube. The characteristic time span of the plasma at the interface is up to 20 μs and the diameter up to 5 mm. These parameters were studied using the two independent techniques: ultra-fast imaging and photomultiplier measurements. Generation of supplementary reactive species at the interface, the NO molecules, was proved by optical emission spectroscopy.
High frequency modulation of mid-infrared quantum cascade lasers embedded into microstrip line
Authors: Calvar A. , Amanti M. I. , Renaudat St-Jean M. , Barbieri S. , Bismuto A. , Gini E. , Beck M. , Faist J. , Sirtori C.
Published: May 2013

In this work, we have studied the frequency response to a direct current modulation of a mid-infrared quantum cascade laser that has been monolithically integrated within a microwave strip. By merging microwave and semiconductor laser technologies, we have demonstrated a flat frequency response up to ∼15 GHz for a device operating at 77 K and emitting at 9 μm. Laser performances are preserved and comparable to state of the art devices. Finally, in our devices, we have observed that the modulation bandwidth varies substantially upon the laser photon density. Improved frequency response is indeed achieved, while lasers operate well above threshold.
Emulating the paired-pulse facilitation of a biological synapse with a NiOx-based memristor
Authors: Hu S. G. , Liu Y. , Chen T. P. , Liu Z. , Yu Q. , Deng L. J. , Yin Y. , Hosaka Sumio
Published: May 2013

We study the paired-pulse-induced response of a NiOx-based memristor. The behavior of the memristor is surprisingly similar to the paired-pulse facilitation of a biological synapse. When the memristor is stimulated with a pair of electrical pulses, the current of the memristor induced by the second pulse is larger than that by the first pulse. In addition, the magnitude of the facilitation decreases with the pulse interval, while it increases with the pulse magnitude or pulse width.
Enhanced measurement of broadband nanomechanical property of polymers using atomic force microscope
Authors: Ren Juan , Mousavi Aliyeh , Li Xuemei , Zou Qingze , Erina Natalia , Su Chanmin
Published: May 2013

A control-based approach to achieve accurate indentation and broadband nanomechanical quantification using atomic force microscope is proposed and utilized to measure four different polymers. For broadband nanomechanical measurement, conventional method is limited by its inability to account for the dynamics effect of the piezoelectric actuator and the cantilever fixture, and the lateral-vertical coupling effect on the cantilever deflection. The proposed approach substantially improved the accuracy of indentation and nanomechanical measurements by utilizing control technique to compensate for these adverse effects. A polydimethylsiloxane sample and three low-density polyethylene samples with different densities were measured by using this approach. The results showed that the viscoelasticity of these four polymer samples can be consistently measured over a large frequency range (100 Hz to 6 kHz) with merely 1 sec. measurement time.
Dispersion relations for evaluating the complex refractive index of medium without the information of its thickness
Authors: Peiponen Kai-Erik , Vartiainen Erik M. , Unuma Takeya , Axel Zeitler J. , Silfsten Pertti , Venäläinen Tapani , Kishida Hideo
Published: May 2013

A general method to obtain the complex refractive index of a medium from absorbance, or alternatively from optical path length data, without knowing the sample thickness is proposed. The method can be formulated in any spectral range and it is here applied particularly in the terahertz spectral range to both simulated and experimental data. The key idea is the derivation of nonconventional dispersion relations that partly resemble traditional Kramers-Kronig relations. The method is shown to work well in extracting the complex refractive index of a drug system and a precipitated calcium carbonate.
Correlation of oxygen vacancy variations to band gap changes in epitaxial ZnO thin films
Authors: Liu Hongyan , Zeng Fei , Lin Yisong , Wang Guangyue , Pan Feng
Published: May 2013

The modulation of oxygen vacancies in ZnO epilayers and its effect on optical band gap have been investigated. The evolution of band gap is correlated with the oxygen vacancy variations induced by readily varying reactive oxygen partial pressure. The oxygen vacancy increased with the decreased oxygen partial pressure, accompanied with a red shift of absorption band edge and of ultraviolet emission peak. The optical band gap was roughly linear dependent on reactive oxygen partial pressure. The band gap narrowing is attributed to the overlap of the nonlocalized oxygen vacancy states with valence band.
Valence band structure of YMnO3 and the spin orbit coupling
Authors: Kumar Manish , Choudhary R. J. , Phase D. M.
Published: May 2013

Electronic structure of pulsed laser deposited hexagonal-YMnO3 film on Al2O3 (0001) substrate has been investigated by photoemission spectroscopy using variable energy photon sources. Resonance photoemission results reveal the charge transfer nature of h-YMnO3 and variation in strength of hybridization between oxygen 2p and Mn 3d across the valence band region. The valence states sensitive to lattice distortion (inversion asymmetry) demonstrate the evolution of spin orbit interaction (SO). This SO along with its anisotropic behavior is well identified by the constant initial state plots.
Low-voltage driven ∼1.54 μm electroluminescence from erbium-doped ZnO/p+-Si heterostructured devices: Energy transfer from ZnO host to erbium ions
Authors: Yang Yang , Li Yunpeng , Xiang Luelue , Ma Xiangyang , Yang Deren
Published: May 2013

It is well known that the light emission at ∼1.54 μm falls within the minimum loss window of silica optic fibers for optical communication and is of significance for the silicon-based optoelectronic integration. Herein, we report on erbium (Er)-related electroluminescence (EL) at ∼1.54 μm from Er-doped ZnO (ZnO:Er)/p+-Si heterostructured light-emitting devices. Such Er-related ∼1.54 μm EL can be enabled at a voltage as low as 6 V. It is derived that the Er-related ∼1.54 μm EL is triggered by transfer of the energy released from the defect-assisted indirect recombination in the ZnO host to the incorporated Er3+ ions. We believe that the present achievement paves the way for the Si-compatible ∼1.54 μm light emitters using the cost-effective oxide semiconductors as the hosts of Er3+ ions.
Mid-infrared electroluminescence from a Ge/Ge0.922Sn0.078/Ge double heterostructure p-i-n diode on a Si substrate
Authors: Tseng H. H. , Wu K. Y. , Li H. , Mashanov V. , Cheng H. H. , Sun G. , Soref R. A.
Published: May 2013

We report the observation of mid-infrared room-temperature electroluminescence from a p-i-n Ge/Ge0.922Sn0.078/Ge double heterostructure diode. The device structure is grown using low-temperature molecular beam epitaxy. Emission spectra under various injection current densities in the range of 318 A/cm2–490 A/cm2 show two distinct profiles peaked at 0.545 eV (2.275 μm) and 0.573 eV (2.164 μm), corresponding to indirect and direct bandgaps of the Ge0.922Sn0.078 active layer, respectively. This work represents a step forward towards the goal of an efficient direct-bandgap GeSn light-emitting device on a Si substrate by incorporating higher Sn content of 7.8% in a diode structure that operates at lower current densities.
Minimization of reflection at the boundaries of a finite-size coupled terahertz cavity in a metal air-gap waveguide
Authors: Lee Sun-Goo , Su Lee Eui , Jeon Tae-In , Kee Chul-Sik
Published: May 2013

We show that reflections at the boundaries of a finite-size coupled terahertz cavity in a metal air-gap waveguide can be minimized by introducing antireflection slits. The optimal values of design parameters for the minimal reflection can be obtained using the one-dimensional antireflection coating theory and finite-difference time-domain simulations. It is experimentally demonstrated that the optimized antireflection slits significantly reduce the finite-size effects such as the strong Fabry-Pérot oscillations in the transmission spectrum and the variations in the group velocity curve.
Dielectric response and magnetoelectric coupling in single crystal gallium ferrite
Authors: Mukherjee Somdutta , Gupta Rajeev , Garg Ashish
Published: May 2013

Here we report the dielectric response and electric conduction behavior of magnetoelectric gallium ferrite single crystals studied using impedance analysis in time and temperature domain. The material exhibits two distinct relaxation processes: a high frequency bulk response and a low frequency interfacial boundary layer response. Calculated bulk capacitance as a function of temperature showed an anomaly at ferri- to paramagnetic transition temperature (∼ 300 K), suggestive of magneto-dielectric coupling in the material. Interestingly, we also witness an abrupt change in the activation energy at ∼ 220 K, in the vicinity of spin-glass transition temperature in GaFeO3.
Negotiating norms, navigating care: findings from a qualitative study to assist in decreasing health inequity in cardiac rehabilitation
Authors: Haghshenas Abbas , Davidson Patricia M , Rotem Arie
Published: May 2013

Purpose. People from culturally and linguistically diverse backgrounds (CaLDBs) have lower rates of participation in cardiac rehabilitation (CR). Systematically evaluating barriers and facilitators to service delivery may decrease health inequalities. This study investigated approaches for promoting cultural competence in CR. Methods. A qualitative study of 25 health practitioners was undertaken across three CR programs using a purposive sampling strategy. Interviews and participant observation were undertaken to identify factors to promote culturally competent care. Results. Three key foci were identified for implementing cultural competence approaches: (1) point of contact; (2) point of assessment; and (3) point of service. Based upon study findings and existing literature, a conceptual model of cultural competency in CR was developed. Conclusion. Culturally competent strategies for identifying and tailoring activities in the CR setting may be a useful approach to minimise health inequities. The findings from this study identified that, in parallel with mainstream health services, CR service delivery in Australia faces challenges related to cultural and ethnic diversity. Encouragingly, study findings revealed implementation and integration of culturally competent practices in rehabilitation settings, in spite of significant odds. What is known about the topic? Cultural competence can improve the ability of health systems and health providers to deliver appropriate services to diverse populations in order to reduce disparities and improve health outcomes. What does this paper add? Description of cardiac rehabilitation practitioners’ interaction and views on interacting with patients from culturally and linguistically diverse backgrounds. An empirically derived model of cultural competence identifying key points of intervention. What are the implications for practitioners? This model improves practitioner’s ability to address diverse needs of individuals from culturally and linguistically diverse backgrounds and improve equity in health care delivery in Australia.
Trial of an allied health workload allocation model
Authors: Simmons Nadine C. , Kuys Suzanne S.
Published: May 2013

Allied health (AH) managers need to be able to quantify workloads to effectively manage the increasing demands on the health system. Workload allocation models provide a means of monitoring, evaluating and determining manageable workloads. This allows managers to ensure equitable distribution of duties and maximise the existing AH workforce output, which will lead to more efficient health service delivery and better patient outcomes. The purpose of this study was to develop and trial an AH workload allocation model incorporating the National Allied Health Casemix Committee Health Activity Classification. A workload allocation model was developed that included a staff workload mapping tool, data analysis spreadsheet and guidelines for calculating procedure times. The model was trialled across three AH professions (occupational therapy, physiotherapy and speech pathology), in two hospital districts, and across inpatient, outpatient and community settings. A total of 30 participants completed the trial. Staff and managers completed a post-trial survey to provide feedback on the workload allocation model. Survey results indicated that staff and managers found the model useful for evaluating and quantifying workloads. Managers believed the model would be useful for preparing business cases and benchmarking staff workloads. Recommendations for improvements to the workload mapping tool were also identified.

What is known about the topic?
Workload allocation models have been identified as a valuable means of evaluating and managing AH workloads. Current models do not account for all tasks undertaken by AH clinicians or are applicable to only a specific AH discipline. There is a paucity of workload allocation models suitable for use across AH disciplines.

What does this paper add?
This paper demonstrates the effectiveness of an AH workload allocation model that incorporates the NAHCC Health Activity Classification that can be used across AH disciplines and work sites.

What are the implications for practitioners?
This new workload allocation model provides AH managers with a mapping tool that provides a high level of detail of non-patient activities, and guidelines for calculating procedure times that can be used to effectively manage staff workloads, benchmark existing services and plan for new services. Critical evaluation of staff workloads will allow managers to maximise allied health human resources and hence provide better patient outcomes.
How is advance care planning conceptualised in Australia? Findings from key informant interviews
Authors: Rhee Joel J. , Zwar Nicholas A.
Published: May 2013

Objective. Advance Care Planning (ACP) has been gaining prominence as an important component of good end-of-life care. This study explored how ACP is conceptualised by stakeholder organisations and clinicians involved in aged care and end-of-life care in Australia, in particular their views on the aim, appropriate context and settings for ACP, and how ACP should be facilitated. Participants. Twenty-three participants including expert clinicians and representatives of government organisations, professional societies, consumer groups and other organisations involved in aged care and end-of-life care. Design. Qualitative descriptive analysis of semi-structured telephone interviews. Results. Most participants viewed ACP as an ongoing process aimed at enhancing an individual’s autonomy and ensuring good end-of-life care. However, there were significant differences in how this process was conceptualised. Some viewed ACP as a process undertaken by patients to define and communicate their treatment preferences. Others viewed ACP as discussions undertaken by health professionals to gain a better understanding of the patient’s values and goals in order to provide good care. Implications. Our findings highlight significant differences in how ACP is conceptualised in Australia. A shared conceptualisation and agreement on purpose is needed to ensure a successful implementation of ACP in Australia. What is known about the topic? Advance care planning (ACP) has been gaining increasing prominence both internationally and in Australia and is seen as an important component of good end-of-life care. Originally conceptualised as a document outlining a patient’s specific treatment preferences about life-sustaining treatments, ACP has been increasingly recognised in the literature as an ongoing process of discussion, communication and documentation of the patient’s wishes and values regarding end-of-life care. What does this paper add? This paper shows that most expert clinicians and representatives of key stakeholder organisations view ACP as a process that aims to enhance individual autonomy and ensure good end-of-life care. However, our findings show that they often hold contrasting views on ACP – ranging from a consumer-orientated view that sees ACP as undertaken to define and communicate their care preferences; to a care-orientated view that sees ACP as discussions led by health professionals in order to gain an understanding of patients’ values and wishes in order to provide better care. What are the implications for practitioners? Our findings highlight significant differences in how ACP is conceptualised in Australia. This can cause confusion and conflict, leading to reduced effectiveness of ACP. A shared conceptualisation and agreement on purpose is needed to ensure a successful implementation of ACP in Australia.
Parasites of the northern hairy-nosed wombat Lasiorhinus krefftii: Implications for conservation.
Authors: Gerhardt K , Smales LR , McKillup SC
Published: May 2013

The northern hairy-nosed wombat Lasiorhinus krefftii is now restricted to a single population of
less than 70 individuals at Epping Forest National Park, North Queensland, Australia, and is
listed as critically endangered. We examined six trapped animals for ectoparasites, and 197
faecal samples for endoparasites. All ectoparasites (the tick Ambylomma triguttatum, the flea
Echidnophaga cornuta and the louse Boopia dubia) were new host records. Nematode eggs and
larvae were found in every faecal sample and the number of eggs varied significantly among
months sampled. Cestode proglottids were also found. There was no indication that parasites
were causing disease and few species were detected. This last remaining population of L. krefftii
may be relatively immunologically na�ve, and we suggest that removing them from their natural
environment to other areas as part of a captive breeding program should be attempted with
caution.
Sex-biased dispersal in the rufous bettong Aepyprymnus rufescens.
Authors: Johnson CN , Payne A
Published: May 2013

STUDIES of dispersal and philopatry in
Macropodoid marsupials have revealed strong sexdifferential
patterns, consistent with those found in
other mammals (Johnson 1989; Greenwood 1980). In
the macropodids (kangaroos and wallabies), males
disperse at sexual maturity, over distances several
times greater than the diameter of their mother?s
home range. Females typically remain close to their
birth place, often settling within the maternal home
range, resulting in long-term association of female
kin. Dispersal in potoroids (rat-kangaroos) is far less
well understood. Although movements of adults have
been studied in several species, there are only two
indications of the pattern of natal dispersal and
philopatry. Christensen and Maisey (1987) suggested
that in the woylie Bettongia penicillata sub-adults
probably dispersed over short distances, and that such
dispersal was male-biased. Pope (2001) used
microsatellite assignment tests and pairwise analysis
of relatedness to infer that dispersal was also malebiased
in B. tropica.
Variation in body temperature in free-ranging western grey kangaroos Macropus fuliginosus.
Authors: Maloney SK , Fuller A , Kamerman PR , Mitchell G , Mitchell D
Published: May 2013

Using implanted temperature loggers we measured temperature in the carotid artery in five (4
male, 1 female) western grey kangaroos (Macropus fuliginosus) every 5 min for between 39 and
74 days. Dry bulb temperature during the study ranged from an average minimum of (mean �
SD) 11 � 3�C to maximum of 24 � 5�C. Black globe temperature measured in the southern
shade of a grass tree, the habitat chosen by kangaroos during the day, ranged from an average
minimum of 10 � 4�C to an average maximum of 30 � 6�C. There were nine days where
maximum shade globe temperature exceeded 40�C. Carotid blood temperature averaged
36.5 � 0.1�C (n = 5), ranging from an average minimum of 35.5 � 0.3�C to a maximum of 37.3
� 0.1�C The resultant average daily range was 1.8 � 0.3�C. Body temperature was highest
during the night and dropped rapidly early in the morning, reaching a nadir at 1000 hours, after
ambient temperature and solar radiation had begun increasing. Body temperature then rose
gradually during the day to reach a peak in the early evening. The nychthemeral variation in
carotid blood temperature was largely independent of ambient conditions. There was a weak but
significant association between early morning radiation levels and the minimum body
temperature reached, suggesting that peripheral warming influences the morning decrease in
core temperature.
A comparison of the diets of feral cats Felis catus and red foxes Vulpes vulpes on Phillip Island, Victoria.
Authors: Kirkwood R , Dann P , Belvedere M
Published: May 2013

THE introduction of feral cats (Felis catus) and red
foxes (Vulpes vulpes) to Australia in the 1800s had a
profound impact on resident ecosystems. Both
predators colonised successfully and now are
distributed across most of mainland Australia
(Saunders et al. 1995; Abbott 2002). They consume
mainly ground-dwelling mammals (Coman 1973;
Croft and Hone 1978; Jones and Coman 1981;
Lapidge and Henshall 2002; Hutchings 2003), but
where these are scarce, birds, reptiles, insects and
human refuse may become important dietary
components (e.g., Bubela et al. 1998; Paltridge
2002). Although they prey on similar species, when
compared at the same location differences in diet
between the predators are evident (Triggs et al. 1984;
Catling 1988; Risbey et al. 1999).
Genetic structure of the western pygmy possum, Cercartetus concinnus Gould (Marsupialia: Burramyidae) based on mitochondrial DNA
Authors: Pestell A.J.L. , Cooper S.J.B. , Saint K. , Petit S.
Published: May 2013

Cercartetus concinnus Gould (Marsupialia: Burramyidae) has a spatially disjunct distribution, with a broad stretch of saltbush on the Nullarbor Plain forming an apparent barrier between the population: one in southern Western Australia, and another in south-eastern Australia, encompassing South Australia, Victoria, and New South Wales. This disjunct distribution and slight differences in morphology between western and eastern populations have led to conjecture about the taxonomy of this species. This study assessed the taxonomic status of C. concinnus across southern Australia. Analyses using the mitochondrial (mtDNA) ND4 gene showed little phylogeographic structure throughout the wide range of C. concinnus in southern Australia; closely related haplotypes (~0.1% sequence divergence) had a wide distribution from Western Australia to South Australia, suggesting recent genetic connectivity. These data indicate that C. concinnus populations represent a single taxonomic unit (Evolutionarily Significant Unit) throughout the geographic range. Further research is required to assess the impact of recent population fragmentation and whether an erosion of genetic variation in isolated populations has occurred.
Longevity and breeding in captive red-tailed phascogales (Phascogale calura)
Authors: Stannard Hayley J. , Borthwick Casey R. , Ong Oselyne , Old Julie M.
Published: May 2013

This paper reports successful breeding by 4-year-old female red-tailed phascogales (Phascogale calura) and that they can survive until at least 5 years of age in captivity, whilst males can survive until at least 2 years of age in captivity. These findings have implications for captive breeding programs, providing evidence that older females can be successfully bred. In the longer term we hope these findings may aid conservation efforts of this endangered dasyurid.
Hormonal growth promotant use in the Australian beef industry
Authors: Hunter R. A.
Published: May 2013

This review focuses on the science that underpins the use of hormonal growth promotants by Australian beef producers. Their effect on increased liveweight gain is reliable and they are used in the grass-fed industry to produce heavier carcasses suitable for the liveweight and age specifications on high value markets. With implants containing only oestradiol, the growth rate response varies between 0.05 and 0.1 kg/day, dependent on the digestible energy intake and the duration of the implant’s functional life for which the animal is in positive energy balance. Combination implants containing both oestradiol and trenbolone acetate promote greater responses in liveweight gain, which can be as high as 0.2 kg/day on good quality pasture. Although there is also accelerated liveweight gain on energy-dense feedlot diets, the main commercial benefit is reduced feed costs associated with improvements in feed conversion efficiency. An example given demonstrates that finishing an implanted steer from 400 to 650 kg reduces feed consumed by ~4%.
Androgenic hormones (testosterone and trenbolone acetate) directly reduce fat content of the carcass. Oestradiol treatment increases mature body size so at any intermediate bodyweight the animal is less mature and likely to have less fat in the carcass. Hormonal treatment has a negative influence on the tenderness and eating quality of beef, the effect being more pronounced with combination implants than with oestradiol alone. Aging for up to 28 days of those muscles that age extensively helps to overcome the detrimental hormonal growth promotant effect.
Relationship between behavioural reactivity and feed efficiency in housed sheep
Authors: Amdi C. , Williams A. R. , Maloney S. K. , Tauson A. H. , Knott S. A. , Blache D.
Published: May 2013

In this study we test the hypothesis that selecting sheep for a low behavioural reactivity to stressful situations will improve their metabolic efficiency, and thereby feed efficiency, during a controlled trial in an animal house. Twenty-four Merino wethers were used, 12 each from lines selected for high (HBR) and low (LBR) behavioural reactivity to stressful stimuli (human presence and social isolation). The sheep were habituated to the experimental procedures for 10 days, followed by 45 days during which voluntary feed intake was measured so that total daily energy intake was quantified. The sheep were weighed twice weekly before daily feeding. Feed efficiency was determined by measuring net feed intake, average daily weight gain and body condition score. Our hypothesis was not supported by the results of this study. There was no difference between LBR and HBR sheep in average daily weight gain or body condition score. The net feed intake of HBR sheep was lower than that of LBR sheep (P = 0.02), indicating that under the conditions of our experiment, HBR sheep were actually more feed efficient than LBR sheep. This study was carried out on sheep with steady intakes and in familiar surroundings. It is possible that LBR sheep may be more efficient than HBR sheep in more stressful situations.
Profitability of grazing crop stubbles may be overestimated by using the metabolisable energy intake from the stubble
Authors: Thomas D. T. , Finlayson J. , Moore A. D. , Robertson M. J.
Published: May 2013

Grazing crop stubbles affects soil structure, groundcover, and the productivity of subsequent crops, but the cost of this practice is highly variable and not easily compared against the value of feed provided to livestock. To compare with and without grazing stubbles in terms of whole-farm profit and water-use efficiency we created a mixed enterprise farm model using the Agricultural Production Systems Simulator and GRAZPLAN biophysical simulation submodels, and the Model of Integrated Dryland Agricultural System linear programming model. We hypothesised that grazing crop stubbles would increase farm profit by an amount equivalent to the value of the metabolisable energy (ME) consumed by sheep when they grazed the crop stubbles. Representative mixed farms where sheep were or were not allowed to graze crop stubbles were compared for two locations in the wheatbelt of Western Australia (Cunderdin and Geraldton) at two stocking rates. Across locations and stocking rates, the estimated value of the ME intake from crop stubbles was 2.2 times the increase in farm gross margin when stubble grazing was allowed. Contributing to this difference was that stubble grazing provided a less flexible feed source than supplementary feeding and in the absence of adjustments in stocking rates sheep tended to utilise more of the annual and permanent pastures when stubble grazing was not permitted. Therefore, the value of grazing crop stubbles to the profitability of the farm enterprise was overestimated by the ME value of the intake. Owing to reduced consumption of supplementary feed by livestock, whole-farm water-use efficiency of protein production was increased by 15% when grazing of crop stubbles was permitted. This simulation study shows that the value of grazing crop stubbles cannot be predicted well using energy intake from stubble grazing or reduced supplementary feeding costs.
Policies and management of overabundant deer (native or exotic) in protected areas
Authors: Nugent G. , McShea W. J. , Parkes J. , Woodley S. , Waithaka J. , Moro J. , Gutierrez R. , Azorit C. , Mendez Guerrero F. , Flueck W. T. , Smith-Flueck J. M.
Published: May 2013

A workshop was convened in Chile in August 2010 as part of the 7th International Deer Biology Congress (IDBC). Its aim was to explore global differences in the policies and management of overabundant deer in protected areas. The main goal of the workshop was to provide South American researchers and managers with a snapshot of some of the approaches to management of deer overabundance used in a diverse array of case studies from North America, Europe, Australia and New Zealand. Various case studies were presented to illustrate the different methodological approaches in implementing deer control measures. Some general recommendations were formulated.
Surveying the management practices and research needs of graziers in the New England region of New South Wales
Authors: Kaine G. , Doyle B. , Sutherland H. , Scott J. M.
Published: May 2013

The inaugural committee of the Cicerone Project commissioned a survey of livestock producers in the New England region to determine the research problems and production practices which were of greatest importance to graziers. In addition, an assessment was made of the level of interest livestock producers had in participating in a proposed producer-led research and adoption project. The survey was mailed to livestock producers in five districts across the New England region during October and November 1997. The survey results concerning land and pasture management issues suggested that a majority of livestock producers in the New England region found the challenges of dry seasons, fertiliser use, pasture composition and pasture persistence to be major problems. A further issue identified was the problem of resistance to drenches used for internal parasite control in sheep. It was clear that producers depend largely on pastures as the primary feed source due to the high cost of supplementary feed. There was considerable interest in learning how to fill gaps in the feed supply, and the management of the feed supply through droughts. Thus, one desired focus of future studies was to explore management systems that might improve the productivity, resilience, stability and longevity of pastures in the New England region. In addition, a focus on grazing management and its effects on pastures and on internal parasite control was suggested by survey respondents. Of the 316 responses to the survey, 76% expressed interest in becoming involved in the Cicerone Project, confirming the desirability of forming a producer-led research and adoption network within the New England region. One hundred and eighty-one respondents expressed an interest in becoming partner members, 100 respondents indicated they were interested in having their farm included in a network, while 139 people were interested in attending regional workshops where further details about the nature of the Cicerone Project would be developed. The survey was clearly of interest to commercial-scale livestock producers as the average size of respondents’ sheep flocks and cattle herds was over 5000 and 500, respectively. The results of this survey provided empirical evidence to support the formation of the Cicerone Project, which was created in 1998 following the approval of a business plan by the primary funding agency, the Woolmark Co.
Does dam pre-breeding nutrition and/or birth rank affect the glucose and fat metabolism of 18-month-old female offspring?
Authors: Pain S. J. , van der Linden D. S. , Kenyon P. R. , Blair H. T.
Published: May 2013

Twin- and triplet-born lambs are smaller and lighter at birth than singletons and remain so until at least 1 year of age. However, there is little evidence in the literature to demonstrate if these smaller/lighter twin- and triplet-born lambs are metabolically different to singletons later in life. Additionally, many studies have demonstrated that dam nutrition during the periconceptual period can program the fetus in utero, influencing development, growth and performance later in life. However, little is known regarding the impact of differing levels of maternal nutrition before the periconceptual period, during the period of preantral follicle development. This study aimed to determine if dam pre-breeding nutrition (High versus Maintenance, 113–71 days pre-breeding) and birth rank (single versus twin versus triplet) affected the metabolic responses of ewes at 18 months of age, to an intravenous glucose (0.17 g/kg liveweight) (GTT) and insulin (0.15 IU/kg liveweight) (ITT) tolerance test. Dam pre-breeding nutrition had no effect (P > 0.05) on glucose and insulin responses to GTT, or glucose and cortisol responses to ITT. However, before both GTT and ITT, ewes born to High-fed dams had greater (P < 0.05) β-hydroxybutyrate (β-HBA) baselines than those born to Maintenance-fed dams, and also had greater (P < 0.05) maximum β-HBA change in response to both GTT and ITT. Birth rank tended (P = 0.06) to affect maximum glucose concentration change in response to glucose administration, with twin-born ewes having a greater increase in glucose compared with both singletons (P = 0.06) and triplet-born (P < 0.05) ewes in response to a glucose challenge. Insulin area under the curve 0–120 min after glucose administration of twin-born ewes was lower (P = 0.05) than both single- and triplet-born ewes. Prior to ITT, baseline β-HBA concentrations of single-born ewes were lower (P < 0.05) than triplet-born ewes. Single-born ewes had a reduced (P < 0.05) decrease in β-HBA change compared with twin- and triplet-born ewes in response to ITT. In summary, this study showed little difference in glucose and insulin metabolism of single-, twin- and triplet-born lambs at 18 months of age. However, the level of dam nutrition 113–71 days pre-breeding appears to have lasting effects on β-HBA metabolism in ewe progeny. The next step is to determine if these metabolic differences result in any measurable animal performance differences, as this would have implications for feeding regimes of ewes before mating and selection of appropriate ewe progeny for use as replacement animals.
Triiodothyronine influences digesta kinetics and methane yield in sheep
Authors: Barnett M. C. , Goopy J. P. , McFarlane J. R. , Godwin I. R. , Nolan J. V. , Hegarty R. S.
Published: May 2013

Methane yield from ruminants is positively correlated with mean retention time (MRT) of digesta, which is known to be influenced by the hormone triiodothyronine (T3).We hypothesised that a decrease in the MRT in the rumen in response to administration of a T3 solution to sheep would reduce their methane yield. To test this hypothesis, 10 mature Merino wethers were injected with T3 (300 µg) on two different protocols (daily; n = 5 and every second day; n = 5) and the effect on daily methane yield, digesta MRT, DM digestibility, rumen volatile fatty acid concentrations, microbial protein output and plasma T3 concentrations studied. Compared with when injected with saline (control), injection of sheep with T3 every second day resulted in decreased methane yield (P < 0.05) and lower acetate (P < 0.001), butyrate (P < 0.001) and propionate (P < 0.01) concentrations in the rumen. MRT of digesta, derived from faecal excretion of CoEDTA and Cr-mordanted fibre, were reduced in the total tract (P < 0.001) and hindgut (P < 0.01) but not in the rumen (P > 0.05). DM digestibility was not affected by injection of T3 every second day but water intake (P < 0.05) and urine output (P < 0.01) were increased. When sheep were injected with T3 daily, changes were only observed in plasma T3 concentration (P < 0.001) and volume of CO2 produced (P < 0.05). The results indicate that increasing plasma concentration of the thyroid hormone T3 within physiological levels reduces digesta retention time, especially retention time in the hindgut and leads to a reduction in enteric methane yield. Further work is warranted to assess whether plasma T3 concentrations may be indicative of enteric methane yield.
Effect of elevated temperatures on bovine corpus luteum function: expression of heat-shock protein 70, cell viability and production of progesterone and prostaglandins by cultured luteal cells
Authors: Iwazawa Makoto , Acosta Tomas J.
Published: May 2013

Summer heat stress lowers fertility in cattle in hot environments by influencing oocyte quality, follicular activity and progesterone (P4) level in blood plasma. However, the mechanisms by which elevated temperature influences corpus luteum function remain unclear. Elevated temperature has generally been known to upregulate the gene expression of heat-shock protein (HSP) 70 in a variety of cell types. To clarify the direct effects of elevated temperature on bovine corpus luteum function, we examined the expressions of HSP70, cell viability and the production of P4 and prostaglandins (PGs) in luteal cells cultured at 37.5°C (normal temperature in our culture system), 39.0°C (moderately elevated temperature) or 41.0°C (severely elevated temperature) for 12 or 24 h. HSP70 mRNA expression was increased by incubation at 39.0°C for 12 h and at 41.0°C for 12 and 24 h, whereas HSP70 protein expression was not significantly affected. The viability of luteal cells cultured for 24 h, measured by flow cytometry with propidium iodide staining, was not significantly affected by temperature. Interestingly, the production of P4 by cultured luteal cells was higher at 39.0°C than at 37.5°C after 12 and 24 h of incubation. The production of PGF2α was higher at 39.0°C and 41.0°C than at 37.5°C after 12 and 24 h of incubation. The production of PGE2 was higher at 41.0°C than at 37.5°C after 24 h of incubation. The overall results suggested that elevated temperature does not negatively affect luteal function, and that the low fertility observed during summer is not due to a direct effect of elevated temperature on luteal cells.