Farms In Australia Research Articles

Retrospective study

Downer cows, defined as a bright and alert cow recumbent for more than 1 day, are often challenging cases for veterinarians and farmers. This article reviews findings for 37 downer dairy cows that originally become recumbent from hypocalcemia ( milk fever) on commercial dairy farms in Australia. Clinical examination determined that they had apparently recovered from primary hypocalcemia, and remained recumbent from secondary damage. There was a wide range of secondary damage, which mainly affected the musculoskeletal system, but other parts of the body were also affected. It was concluded that downer cow syndrome is due to clinically important secondary damage, defined as "secondary damage that can cause recumbency in its own right, or delay or prevent recovery from the primary cause of the recumbency". Clinically important secondary damage in downer cows can present in a wide range of types, and is not necessarily confined to the musculoskeletal system. This study demonstrated a wider range of secondary damage than considered in the literature. When managing recumbent dairy cows, in addition to the primary etiology of the recumbency, veterinarians must consider secondary damage.

Precarious work and the reluctance to complain: Italian temporary migrant workers in Australia

ABSTRACT The reluctance of many temporary migrant workers (TMWs) to challenge poor wages and conditions is an important puzzle for both research and policy. This article explores the puzzle by drawing on in-depth interviews with Italian TMWs who have had recent work experience in food services and/or farms in Australia. The article describes their experiences of precarious work, marked by widespread and systematic underpayment of wages in breach of minimum wage regulation. It shows that few Italian TMWs challenged underpayments, whether through collective or individual action. The article reviews the varied rationales offered by the interviewees for their reluctance to pursue an individual complaint about underpayments. It finds that fear of employer reprisals was a powerful and understandable barrier to action. Also influential, however, were attitudes that had the effect of downplaying the significance of low pay in the current job, for example, by means of a judgment that the current job is only a temporary stage in a long-term life-course project. The findings indicate that reluctance to complain needs to be situated in relation to other forms of migrant worker agency, both within and outside the workplace, and the social relations in which they are embedded.

An assessment of worm control practices used by alpaca farmers in Australia

This study aimed to assess current worm control practices used by Australian alpaca farmers with an online questionnaire survey. The questionnaire contained questions about farm demography and general husbandry practices, farmers’ knowledge about gastrointestinal nematodes (GINs) and their importance, the use of worm control strategies and anthelmintics, and grazing management. A link for the questionnaire survey was sent to all (n = 954) registered members of the Australian Alpaca Association in July 2015. The response rate for the questionnaire was 25% (239/954). The majority of respondents were from small (≤ 50 alpacas; 64%, 153/239) followed by medium (50–100 alpacas; 24%, 57/239) and large (>100 alpacas; 12%, 29/239) farms. Findings revealed that the majority of respondents kept Huacaya alpacas to produce high-quality fibre and alpacas were usually kept with other domestic ruminants (e.g. cattle and sheep). Although half of alpaca farmers (114/220) perceived that GINs were an important health problem of alpacas, with Haemonchus spp. being the most common nematode, the majority of them (174/220) used anthelmintics for nematode control. Macrocyclic lactones, a commercial combination of four anthelmintics (abamectin, albendazole, closantel and levamisole) and monepantel were the three most commonly used dewormers by Australian alpaca farmers. Although a significant proportion (166/213) of respondents used a quarantine drench for alpacas, very few respondents were aware of strategic deworming and the issue of anthelmintic resistance. Alpaca farmers mostly used anthelmintics at the dose rate recommended for sheep (47%, 79/167) and cattle (9%, 15/167), though some used 1.5 (31%, 51/167) and 2 (13%, 22/167) times the dose rate recommended for sheep. The majority of small herds used anthelmintics at the dose rate recommended for sheep and cattle while medium and large herds used anthelmintics at 1.5 to 2 times the dose rate recommended for sheep. This study provides invaluable insights into the demography of alpaca farms in Australia, husbandry practices used by alpaca farmers and their knowledge about worms and their control, thereby paving the way for developing guidelines for the control of GINs of alpacas.

Farmer survey to assess the size of the Australian dairy goat industry

To better understand the commercial food-producing Australian dairy goat industry. We contacted all licensing boards and telephone surveyed a large sample of Australian dairy goat farmers producing food products on demographics, production and labour. Jurisdictional licensing boards confirmed there were 68 licensed dairy goat farms in Australia in 2016. We surveyed representatives from 41. Of the farmers surveyed 20 were female and 19 were male; 81% were over 40 years old. The median number of milking goats per farm was 96 and the median total number of goats per farm was 150. The mean number of litres of milk produced per milking goat per day was 2.5. A total production of 9.6 million litres of milk was reported from these 41 farms alone in 2016, suggesting an increase in production since 2012. Production included 60% sold as cheese, 18% as fresh milk and the remaining as milk powder or other products. Most of the respondents (73%) supported the development of an industry group. If the farmers surveyed are representative, we estimate that in 2016 there were 30,550 milking goats in the Australian national herd, producing 16,867,792 litres of milk with a farm-gate value of AU$20-27 million. This is a significant increase on the estimates made in 2009 and 2012 and suggests the industry is expanding.

The Australian digital farmer: challenges and opportunities

Any agricultural farm enterprise is a complex undertaking. Physical, economic, social and technological factors demand equal attention if a farm enterprise is to succeed. To be successful a farmer needs to ensure the optimal use of farm inputs to achieve high productivity. Technological developments have dragged farmers into the digital age and have significantly altered the management of such inputs. This paper considers the disruption brought about by digital farming. Major technical, legal, policy and social challenges and opportunities are outlined in the context of digital farming in Australia.

Fertiliser strategies for improving nitrogen use efficiency in grazed dairy pastures

Evidence from farm level studies indicates that there is potential to improve nitrogen (N) use efficiency of the predominately pasture-based dairy farms in Australia. This is possible via several ways which includes modifying the timing and rates of N fertiliser applied to pasture. Traditionally fertiliser strategies have been based on a “recipe” approach where N fertiliser, primarily urea, is applied a set rate following grazing. The aim of this study was to compare the pasture dry matter response, N loss and response rate of fertiliser strategies which used increasing knowledge of plant and soil conditions in different ways. The study was conducted under grazing conditions using the biophysical model, DairyMod and repeated at several locations and farming systems in the dairy regions of Australia. In comparison to set rates this study showed that strategic approaches to N fertiliser have the potential to be more efficient in N use and lower both N inputs and N losses with little impact of pasture production. This was evident across all seasons and locations studied. Strategies that used the plant N status to trigger fertiliser timing and rates were more efficient and had lower environmental N losses than those that used fixed rates or soil N information. Fertilising per plant N requirements was the most efficient – and therefore should be the priority for development – particularly in view of the greater expense of fertilisers that are slow release. Precision fertiliser management strategies have the value in terms of reducing fertiliser use and loss during autumn and to a lesser extent in summer, with the least value in winter. However, for the strategies to be properly evaluated for pasture based dairy farms with grazing, a whole farm analysis needs to be conducted that incorporates other sources of feed. This is a necessary inclusion in any subsequent studies.

Big data and machine learning for crop protection

Crop protection is the science and practice of managing plant diseases, weeds and other pests. Weed management and control are important given that crop yield losses caused by pests and weeds are high. However, farmers face increased complexity of weed control due to evolved resistance to herbicides. This paper first presents a brief review of some significant research efforts in crop protection using Big data with the focus on weed control and management followed by some potential applications. Some machine learning techniques for Big data analytics are also reviewed. The outlook for Big data and machine learning in crop protection is very promising. The potential of using Markov random fields (MRF) which takes into account the spatial component among neighboring sites for herbicide resistance modeling of ryegrass is then explored. To the best of our knowledge, no similar work of modeling herbicide resistance using the MRF has been reported. Experiments and data analytics have been performed on data collected from farms in Australia. Results have revealed the good performance of our approach.

Emergence of highly prevalent CA-MRSA ST93 as an occupational risk in people working on a pig farm in Australia.

BackgroundThe occurrence of livestock-associated (LA) MRSA (ST398) in pig herds has emerged as a threat to occupational safety in many parts of the world. Recently, an outbreak of skin lesions due to MRSA occurred in workers at a pig farm in regional Australia and both the humans and pigs were shown to have a high prevalence of carriage of either the human-strain ST93 or porcine strain ST398. This study closely scrutinises this outbreak to determine factors associated with MRSA carriage amongst the workers.MethodsInformation on potential risk factors was collected from employees by means of a questionnaire. The carriage status of MRSA by workers was assessed by nasal swabs processed using standard laboratory techniques with confirmed isolates subjected to sequence typing. Associations between MRSA carriage in workers and their questionnaire responses were investigated using univariable and multivariable logistic regression.ResultsNasal carriage of MRSA was identified in 60% (31/52) of participants. Workers having contact with pigs had 24 times the odds of MRSA carriage compared to workers with no direct contact (OR 23.6; CI 5.2–172.8). In addition, the probability of MRSA carriage in workers was significantly (P < 0.001) associated with the number of hours in contact with pigs and each hour of contact-time per day increased the risk of MRSA carriage by 1.44 times (CI 1.14–1.96). These associations were significant (P < 0.001) for both strains, ST398 and ST93, present on this farm. Using a multivariable logistic regression model that incorporated human exposure to five different pig age groups (dry sows, farrowing, weaner, grower, and finisher) as fixed effects, a significant (P = 0.027) increased odds of MRSA carriage was found for persons working with farrowing sows compared with those who did not (OR 6.39, CI 1.23–39.36).ConclusionsThis study shows that workers in close contact with pigs on a pig farm where MRSA is present had a higher risk of MRSA carriage as the number of hours of direct contact with pigs increased. Since we have detected a significant association for the human-derived CA-MRSA ST93, similar to the pig-adapted LA-MRSA ST398, we consider ST93 as a potential occupational risk for piggery workers. The risk of MRSA carriage is greatest when working with the farrowing group; therefore, an emphasis is required on personal protective equipment while working in the farrowing house. The study has ramifications for the conduct of surveillance for MRSA in people exposed to pigs.

Genomic characterization of coagulase-negative staphylococci including methicillin-resistant Staphylococcus sciuri causing bovine mastitis

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) have recently emerged as a significant cause of bovine mastitis worldwide. Here we describe the isolation of MRCoNS from cases of bovine mastitis from a single dairy farm in Australia. Fourteen CoNS isolates were identified as MRCoNS on the basis of having an oxacillin MIC of ≥0.5 μg/mL. The isolates were speciated as S. chromogenes (n = 1) S. fleurettii (n = 1), S. haemolyticus (n = 2), S. sciuri (n = 5), S. simulans (n = 1) S. succinus (n = 2) and S. xylosus (n = 2). Five of the isolates (S. fleuretti, S. haemolyticus S. sciuri and two S. succinus) were mecA-positive. We also detected a previously described S. sciuri mecA homolog in four oxacillin-resistant S. sciuri isolates. The remainder of the putative MRCoNS did not contain any mecA-related resistance determinants in their genomes. Comparative genomic analysis of three previously published S. sciuri isolates, from humans, a squirrel and a cereal crop (rice), and a representative isolate from our study demonstrated clustering and a high degree of genetic homogeneity (>95%), suggesting S. sciuri has low host specificity. In conclusion, CoNS, in particular S. sciuri, may act as a reservoir for SCCmec elements that can easily be spread between different host species by direct cross-infection.

Gaseous emissions from an intensive vegetable farm measured with slant-path FTIR technique

A recently developed slant-path flux gradient (FG) technique, combined with open-path Fourier transform infrared (OP-FTIR) spectroscopy, was deployed to concurrently measure gas emissions of ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) from an intensive vegetable farm in Australia. Gas fluxes were continuously measured for three weeks following chicken manure application to a celery crop, followed by intermittent measurements for three days a week for another three weeks. The average flux measured over the 41 day measurement period for NH3 and N2O, was 5.2 and 2.9 mg N m−2 h−1, respectively, CH4 was 1.1 mg C m−2 h−1, and CO2 was 0.7 C g m−2 h−1. Manure and fertilizer application substantially increased the emissions of these gases, by providing carbon (C) and nitrogen (N) substrates to the soil. The cumulative N losses as NH3 and N2O following fertilizer application were 6.7% and 3.7% of total N applied, respectively. Using this FG/OP-FTIR technique, we demonstrated that the N2O emission factor for this vegetable farm is much higher than the IPCC default emission factor for manure applied to managed lands. These results highlight the need for large-scale measurements to quantify multiple gas losses from intensive agricultural systems.

Correction: Comparisons of management practices and farm design on Australian commercial layer and meat chicken farms: Cage, barn and free range.

[This corrects the article DOI: 10.1371/journal.pone.0188505.].

Assessing the probability of introduction and spread of avian influenza (AI) virus in commercial Australian poultry operations using an expert opinion elicitation.

The objective of this study was to elicit experts’ opinions and gather estimates on the perceived probability of introduction and spread of avian influenza (AI) virus in the Australian broiler and layer industry. Using a modified Delphi method and a 4-step elicitation process, 11 experts were asked to give initial individual estimates for the various pathways and practices in the presented scenarios using a questionnaire. Following this, a workshop was conducted to present group averages of estimates and discussion was facilitated to obtain final individual estimates. For each question, estimates for all experts were combined using a discrete distribution, with weights allocated representing the level of expertise. Indirect contact with wild birds either via a contaminated water source or fomites was considered the most likely pathway of introduction of low pathogenic avian influenza (LPAI) on poultry farms. Presence of a water body near the poultry farm was considered a potential pathway for introduction only when the operation type was free range and the water body was within 500m distance from the shed. The probability that LPAI will mutate to highly pathogenic avian influenza (HPAI) was considered to be higher in layer farms. Shared personnel, equipment and aerosol dispersion were the most likely pathways of shed to shed spread of the virus. For LPAI and HPAI spread from farm to farm, shared pick-up trucks for broiler and shared egg trays and egg pallets for layer farms were considered the most likely pathways. Findings from this study provide an insight on most influential practices on the introduction and spread of AI virus among commercial poultry farms in Australia, as elicited from opinions of experts. These findings will be used to support parameterization of a modelling study assessing the risk of AI introduction and spread among commercial poultry farms in Australia.

Wildlife Presence and Interactions with Chickens on Australian Commercial Chicken Farms Assessed by Camera Traps.

The types of wildlife and the frequency of their visits to commercial chicken farms in Australia were assessed using infrared and motion-sensing camera traps. Cameras were set up on 14 free-range layer farms, three cage layer farms, two barn layer farms, five non-free-range meat chicken farms, and six free-range meat chicken farms in the Sydney basin region and South East Queensland. Wildlife visits were found on every farm type and were most frequent on cage layer farms (73%), followed by free-range layer farms (15%). The common mynah ( Acridotheres tristis) was the most frequent wildlife visitor in the study (23.9%), followed by corvids (22.9%) and Columbiformes (7.5%). Most wildlife visits occurred during the day from 6 am to 6 pm (85%). There were infrequent observations of direct contact between chickens and wildlife, suggesting the indirect route of pathogen transfer may be more significant. The level of biosecurity on the farm is suggested to impact the frequency of wildlife visits more so than the farm type.

Short communication: The effect of temperature-humidity index on milk yield and milking frequency of dairy cows in pasture-based automatic milking systems

Hot weather is known to negatively affect cow performance primarily through reduced feed intake and milk yield. However, little information is available on how it affects cow milk yield and milking frequency in automatic milking systems (AMS). Milking data were collected from 6 pasture-based AMS farms in Australia to assess the effect of temperature-humidity index (THI) on milk yield and milking frequency. Daily measures of average milk yield per cow and average milking frequency per cow during December to February (Australian summer) were assessed for associations with maximum, minimum, and average THI from d 0, -1, -2, and -3 in relation to the milking data. Average daily milk yield per cow was negatively associated with an increasing maximum, minimum, and average THI (-0.11, -0.08, and -0.15 kg/THI unit increase, respectively) on the collection day and up to 3 d prior. The average daily milking frequency was negatively associated with maximum THI on 1 d (-0.003/THI unit increase) and 2 d (-0.003/THI unit increase) before collection. Our results show that high THI conditions were negatively associated with milking frequency and milk yield in a pasture-based AMS and that research into management and infrastructure (cow cooling) in these systems is warranted to reduce production losses.

The impacts of modern-use pesticides on shrimp aquaculture: An assessment for north eastern Australia

The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last decade, and as a consequence, increased concentrations of the neonicotinoid insecticide imidacloprid have been measured in Australian rivers. Previous studies have shown that non-target crustaceans, including commercially important species, can be extremely sensitive to these pesticides. Most shrimp farms in Australia are predominantly located adjacent to estuaries so they can obtain their required saline water, which support multiple land uses upstream (e.g. sugar-cane farming, banana farming, beef cattle and urbanisation). Larval and post-larval shrimp may be most susceptible to the impacts of these pesticides because of their high surface area to volume ratio and rapid growth requirements. However, given the uncertainties in the levels of insecticides in farm intake water and regarding the impacts of insecticide exposure on shrimp larvae, the risks that the increased use of new classes of pesticide pose towards survival of post-larval phase shrimp cannot be adequately predicted. To assess the potential for risk, toxicity in 20day past hatch post-larval Black Tiger shrimp (Penaeus monodon) to modern use insecticides, imidacloprid, bifenthin, and fipronil was measured as decreased survival and feeding inhibition. Post-larval phase shrimp were sensitive to fipronil, bifenthrin, and imidacloprid, in that order, at concentrations that were comparable to those that cause mortality other crustaceans. Bifenthrin and imidacloprid exposure reduced the ability of post-larval shrimp to capture live prey at environmentally realistic concentrations. Concentrations of a broad suite of pesticides were also measured in shrimp farm intake waters. Some pesticides were detected in every sample. Most of the pesticides detected were measured below concentrations that are toxic to post-larval shrimp as used in this study, although pesticides exceed guideline values, suggesting the possibility of indirect or mixture-related impacts. However, at two study sites, the concentrations of insecticides were sufficient to cause toxicity in shrimp post larvae, based on the risk assessment undertaken in this study.

Farmer interest in joint venture structures in the Australian broadacre grains sector

AbstractThere is a growing productivity gap between leading and average grain farms in Australia, driven by a combination of constraints that limit the adoption of innovations. Such constraints may be overcome by the adoption of organizational innovations, including collaborative structures such as joint venture (JV) arrangements. Given the predominance of the owner‐operator family farm model in the Australian grains sector, organizational innovations have largely been overlooked by the research and extension community. This paper examines business alliance formation in agriculture and farmer perceptions of, interest in, and barriers to participation in JV structures. A telephone survey of 573 Australian grain growers revealed that 3% of farmers had adopted a JV structure and that such farms were significantly more likely to have a larger crop area and be less diversified compared to nonadopters. Another 21% of farmers expressed an interest in adopting a JV structure in the future, particularly to reduce costs and improve productivity. A multinomial logit model showed that such farmers were significantly different for a number of sociodemographic variables including age and education, when compared to farmers not interested in adopting JV structures. To build on this basis of interest and motivation for innovative farm business structures, further understanding of perceived trade‐offs and preferences is needed to identify the most attractive JV designs. [EconLit Citation: Q13].

Australian Tongue and Ag-gag Law

In this essay, I comment on two histories of animal farming in Australia in an ecocritical reading of several works of Australian literature: Tim Winton’s novel Shallows (1984), Susan Hawthorne’s collection of poetry, Cow (2011) and Francesca Rendle-Short’s novel Bite Your Tongue (2011). The first of those histories, the background of Shallows, refers to the whaling industry that operated in Western Australian waters up through the 1970s and the growing public awareness of that industry that eventually drove it to a halt in 1978, the year the main events of the novel take place. Cow and Bite Your Tongue, the texts that I mostly discuss, carry references to the history of industrial farming of cows in Australia, which, along with the industrial farming of other domesticated animal species, exploded after 1970 (in Australia and elsewhere in urban-industrialising countries), the same decade when Australians were beginning to rally behind animal rights activists’ opposition to whale slaughter. Today, almost half a century later, animal advocacy activists continue to raise pressing questions about animal species that are industrially farmed. They are doing so at the same time as the meat industry is attempting to restrict public access to and information about its operations. I address those questions in my reading of Hawthorne’s paean to cows and Rendle-Short’s references to the Moral Right movement in Queensland in the 1970s and attempts by its supporters to remove works of literature from school book shelves.

Contesting facts about wind farms in Australia and the legitimacy of adverse health effects.

The development of wind energy in Australia has been subject to ongoing public debate and has been characterised by concerns over the health impacts of wind turbines. Using discursive psychology, we examine 'wind turbine syndrome' as a contested illness and analyse how people build and undermine divergent arguments about wind-farm health effects. This article explores two facets of the dispute. First, we consider how participants construct 'facts' about the health effects of wind farms. We examine rhetorical resources used to construct wind farms as harmful or benign. Second, we examine the local negotiation of the legitimacy of health complaints. In the research interviews examined, even though interviewees treat those who report experiencing symptoms from wind farms as having primary rights to narrate their own experience, this epistemic primacy does not extend to the ability to 'correctly' identify symptoms' cause. As a result, the legitimacy of health complaints is undermined. Wind turbine syndrome is an example of a contested illness that is politically controversial. We show how stake, interest and legitimacy are particularly relevant for participants' competing descriptions about the 'facts' of wind turbine health effects.

Dynamics and distribution of public and private research and extension roles for technological innovation and diffusion: Case studies of the implementation and adaptation of precision farming technologies

Precision farming technologies represent an innovation challenge in terms of their diffusion into farming practice, and create a new dynamic for research and extension roles. The purpose of this paper is to examine the interaction and distribution of research and extension roles of public, private, and agricultural industry organizations in precision farming innovation systems. We connect findings to the broader debates on role divisions of public and private research and extension in innovation systems. Two case studies were examined: precision dairy farming in Australia, and the use of automatic milking systems in north-western Europe. A timeline analysis method, underpinned by a functions of innovation systems framework, was used to examine activities of actors and organizations in the case studies. Three main findings were: 1) Complex agricultural innovations require a collaborative approach for successful innovation and diffusion. The need for, and type of, collaboration differs across scales from farm-level (individual learning) to a national and global level with issues of skill training and service provider capability. Additionally, a threshold scale is required before the commercial sector can operate effectively. 2) The presence, and limitations, of private (commercial) interests and their position as a key knowledge base in precision farming heightens the need for public research and extension organizations to promote collaborative innovation programs with technology companies. There is a key public or industry good role in providing ‘back-office’ activities to support and complement private ‘front office’ activities. 3) Public and private research and extension organizations can work together, however there are areas where it makes more sense for one party or the other to lead. For precision farming systems, the roles for public organizations involve leadership on data integration (on-farm and off-farm), integration of technology (via standards), testing equipment performance, and development of training programs including support of initiatives such as farmer clubs. The principle theoretical implication is that public, private and industry roles in research and extension should not be viewed as dichotomous (e.g. pre-competitive/competitive), but as highly fluid in terms of the moments they are needed, and the scale at which they are needed, within the technological innovation system.

The health and wellbeing of Australian farmers: a longitudinal cohort study.

BackgroundIsolation, long work days, climate change and globalization are just some of the many pressures that make farming a vulnerable occupation for incurring mental health issues. The objective of this study was to determine whether farming in Australia is associated with poorer wellbeing, physical and mental health, and less health service use.MethodsThe Australian Rural Mental Health Study, a longitudinal cohort study was analysed over four time points comparing farmers with non-farming workers (n = 1184 at baseline). Participants were recruited from rural NSW, Australia. A number of physical, mental health, wellbeing, service use outcomes were assessed using generalised estimating equations including all waves in each model. Barriers to seeking help were also assessed.ResultsFarmers who lived remotely reported worse mental health (β −0.33, 95 % CI −0.53, −0.13) and wellbeing (β −0.21(95 % CI −0.35, −0.06) than remote non-farm workers regardless of financial hardship, rural specific factors eg drought worry, or recent adverse events. All farmers were no different to non-farming workers on physical health aspects except for chronic illnesses, where they reported fewer illnesses (OR 0.66, 95 % CI 0.44, 0.98). All farmers were half as likely to visit a general practitioner (GP) or a mental health professional in the last 12 months as compared to non-farm workers regardless of location (OR 0.59, 95 % CI 0.35, 0.97). Rural workers felt that they preferred to manage themselves rather than access help for physical health needs (50 %) or mental health needs (75 %) and there was little difference between farmers and non-farm workers in reasons for not seeking help.ConclusionsRemoteness is a significant factor in the mental health and wellbeing of farmers, more so than financial stress, rural factors and recent adverse events. Creative programs and policies that improve access for farmers to GPs and mental health professionals should be supported.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3664-y) contains supplementary material, which is available to authorized users.