Will rising atmospheric CO2 concentration inhibit nitrate assimilation in shoots but enhance it in roots of C3 plants?

Bloom et al. proposed that rising atmospheric CO2 concentrations 'inhibit malate production in chloroplasts and thus impede assimilation of nitrate into protein of C3 plants, a phenomenon that will strongly influence primary productivity and food security under the environmental conditions anticipated during the next few decades'. Previously we argued that the weight of evidence in the literature indicated that elevated atmospheric [CO2 ] does not inhibit NO3 - assimilation in C3 plants. New data for common bean (Phaseolus vulgaris) and wheat (Triticum aestivum) were presented that supported this view and indicated that the effects of elevated atmospheric [CO2 ] on nitrogen (N) assimilation and growth of C3 vascular plants were similar regardless of the form of N assimilated. Bloom et al. strongly criticised the arguments presented in Andrews et al. Here we respond to these criticisms and again conclude that the available data indicate that elevated atmospheric [CO2 ] does not inhibit NO3 - assimilation of C3 plants. Measurement of the partitioning of NO3 - assimilation between root and shoot of C3 species under different NO3 - supply, at ambient and elevated CO2 would determine if their NO3 - assimilation is inhibited in shoots but enhanced in roots at elevated atmospheric CO2 .

Elevated CO2 effects on nitrogen assimilation and growth of C3 vascular plants are similar regardless of N-form assimilated.

Atmospheric carbon dioxide concentration ([CO2]) increased from around 280 ppm in 1750 to 400 ppm in 2016 and is likely to continue to increase throughout this century. It has been argued that wheat, Arabidopsis, and C3 plants in general respond more positively to elevated atmospheric [CO2] under ammonium (NH4+) nutrition than under nitrate (NO3-) nutrition because elevated CO2 inhibits their photoreduction of NO3- and hence reduces their total plant nitrogen (N) assimilation and ultimately growth. Here, it is argued that the weight of evidence in the literature indicates that elevated atmospheric [CO2] does not inhibit NO3- assimilation and growth of C3 vascular plants. New data for common bean and wheat support this view and indicate that the effects of elevated atmospheric [CO2] on N assimilation and growth of C3 vascular plants will be similar regardless of the form of N assimilated.

Milk production and nitrogen excretion of grazed dairy cows in response to plantain (Plantago lanceolata) content and lactation season.

Objective: The study aimed to quantify milk production and urinary nitrogen (UN) excretion of dairy cows grazing pastures containing varying contents of plantain (Plantago lanceolata) in different seasons, under a typical farm practice. Methods: Four pasture treatments: perennial ryegrass (Lolium perenne) - white clover (Trifolium repens) (RGWC), RGWC + low plantain rate, RGWC + medium plantain rate, and RGWC + high plantain rate, were established in four adaptation areas (1 ha each) and 20 experimental plots (800 m2 each), and rotationally grazed by dairy cows over 14 grazing events during two lactation years. In each grazing (8-9 days), 60 or 80 Jersey-Friesian lactation cows were assigned to their pasture treatments, adapted to their pastures over the first six days, then each group of 15 or 20 cows were randomly allocated for grazing in five treatment plots over a two or three-day measurement period. Milk, urine, and faecal samples were collected from individual cows during the measurement period. Results: The pasture treatments did not affect milk production, the yield and composition of milk solids, protein, fat, and lactose. However, cows grazing pastures containing between 17-28% dietary plantain reduced UN concentration by 15-27%, decreased UN excretion by 4-9%, and increased urine volume by 22-40%, compared to grazing the RGWC pasture. The change in UN concentration, and urine volume were associated with plantain proportion in the diet and were greater during late summer and autumn than during early summer. Conclusion: Incorporating 17%-28% dietary plantain with RGWC pastures can reduce the risk of nitrogen losses from pastoral systems, while maintaining the milk production of dairy cows.

Dairy Cows Grazing Plantain-Based Pastures Have Increased Urine Patches and Reduced Urine N Concentration That Potentially Decreases N Leaching from a Pastoral System.

The objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass-white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems.

Nitrogen Excretion by Dairy Cows Grazing Plantain (Plantago lanceolata) Based Pastures during the Lactating Season.

The use of plantain pasture in dairy systems can potentially reduce nitrogen (N) leaching losses via the lower N concentration in the urine (UNc) of cows. Reducing the urinary N load while cows graze pastures can reduce the risk of N leaching losses from urine patches. Research needs to demonstrate that these environmental benefits are not at the expense of milk production and farm profit. Three groups of 20 cows grazed in the following three pasture treatments: (i) plantain, (ii) plantain-clover mix (plantain, red [Trifolium pratense] and white clover), or (iii) ryegrass-white clover (wc) pastures, from spring to autumn for two years. Each year, pasture intake, diet quality, milk production and animal N (milk and urine) excretion were evaluated in spring, summer, and autumn. The cows grazing the plantain and plantain-clover mix pastures produced similar milk solids as cows grazing ryegrass-wc pasture but reduced their UNc during summer and autumn, when compared to those grazing the plantain-clover mix and ryegrass-wc pastures. Plantain reduced urinary N loads onto pastures by a greater number of urine patches with lower urinary N loading rates. The results demonstrate that plantain pastures do not diminish milk solids production from cows, and the lower UNc from summer to autumn could reduce N being lost to the environment.

The effects of salinity and osmotic stress on barley germination rate: sodium as an osmotic regulator.

BACKGROUND AND AIMS: Seed germination is negatively affected by salinity, which is thought to be due to both osmotic and ion-toxicity effects. We hypothesize that salt is absorbed by seeds, allowing them to generate additional osmotic potential, and to germinate in conditions under which they would otherwise not be able to germinate. METHODS: Seeds of barley, Hordeum vulgare, were germinated in the presence of either pure water or one of five iso-osmotic solutions of polyethylene-glycol (PEG) or NaCl at 5, 12, 20 or 27 °C. Germination time courses were recorded and germination indices were calculated. Dry mass, water content and sodium concentration of germinating and non-germinating seeds in the NaCl treatments at 12 °C were measured. Fifty supplemental seeds were used to evaluate the changes in seed properties with time. KEY RESULTS: Seeds incubated in saline conditions were able to germinate at lower osmotic potentials than those incubated in iso-osmotic PEG solutions and generally germinated faster. A positive correlation existed between external salinity and seed salt content in the saline-incubated seeds. Water content and sodium concentration increased with time for seeds incubated in NaCl. At higher temperatures, germination percentage and dry mass decreased whereas germination index and sodium concentration increased. CONCLUSIONS: The results suggest that barley seeds can take up sodium, allowing them to generate additional osmotic potential, absorb more water and germinate more rapidly in environments of lower water potential. This may have ecological implications, allowing halophytic species and varieties to out-compete glycophytes in saline soils.

Efficiency of Crude Protein Utilisation in Grazing Dairy Cows: A Case Study Comparing Two Production Systems Differing in Intensification Level in New Zealand.

In this study, we modelled and compared lactation curves of efficiency of crude protein utilisation (ECPU) and the nitrogen (N) excreta partitioning of milking cows of two contrasting spring-calving pasture-based herds to test some aspects of farming intensification practices on cow performance and N partition. In the low-intensity production system (LIPS), 257 cows were milked once-daily and fed diets comprised of pasture with low supplementary feed inclusion during lactation (304 kg pasture silage/cow). In the high-intensity production system (HIPS), 207 cows were milked twice-daily and fed pasture with higher supplementary feed inclusion (429 kg pasture silage and 1695 kg concentrate/cow). The dietary crude protein (CP) utilisation was calculated for each cow at every herd test date as the ECPU as a proportion of protein yield (PY) from the CP intake (CPI) derived from intake assessments based on metabolisable energy requirements, and the CP balance (CPB) calculated as the difference between CPI and PY. Total N excreta partitioned to faeces (FN) and urine (UN) was estimated by back-calculating UN from FN, considering dietary N, and from N retained in body tissues, taking into account live weight change during the lactation. The higher CPI (2.7 vs. 2.5 kg CP/day), along with the reduced milk yield (1100 kg milk/cow less), of the LIPS cows led to a lower ECPU (23% vs. 31%) and to a higher CPB (2.1 vs. 1.8 kg CP/day) when compared to the HIPS cows. Mean N excreta, and particularly UN, was significantly higher in LIPS cows, and this was explained by higher dietary CP and by the reduced PY when compared to the HIPS cows. Reducing the low-CP supplementation in the "de-intensified" herd lessened the ECPU, resulting in higher UN, which is sensitive in terms of body water eutrophication.

Selection by Lambs Grazing Plantain (Plantago lanceolata L.), Chicory (Cichorium intybus L.), White Clover (Trifolium repens L.), Red Clover (Trifolium pratense L.) and Perennial Ryegrass (Lolium perenne L.) across Seasons.

Plantain (Plantago lanceolata) and chicory (Cichorium intybus) are now widely used in combination with clover species to provide greater annual lamb live weight gains than perennial ryegrass and white clover pasture. Reported selective grazing of the species in herb-clover mixes could potentially detrimentally change the relative abundance of species and decrease lamb production. Lambs were offered three herbage treatments: Pasture (perennial ryegrass and white clover) mix, plantain (plantain, red clover and white clover) mix and a chicory (chicory, plantain, red clover and white clover) mix in each of four seasons for two years. The experiment was a randomized complete block design with three replicates with 18-30 lambs per treatment replicate depending on the season. Lambs were rotationally grazed and fed ad libitum. Selection by the lambs of individually tagged plants within the pasture treatments was observed for three days on two occasions per season. Red clover was the most selected species on day 1, but by day 3 there was no difference in the selection of the species (p < 0.05). Plantain and chicory in the plantain and chicory mixes were selected less on day 1 in autumn relative to the other seasons (p < 0.05). It was concluded that three days of grazing before moving lambs maintained the relative abundance of species in the herb-clover mixes.

Electromagnetic Interference in Implantable Defibrillators in Single-Engine Fixed-Wing Aircraft.

BACKGROUND: Little is known about the possible electromagnetic interferences (EMI) in the single-engine fixed-wing aircraft environment with implantable cardio-defibrillators (ICDs). Our hypothesis is that EMI in the cockpit of a single-engine fixed-wing aircraft does not result in erroneous detection of arrhythmias and the subsequent delivery of an inappropriate device therapy. METHODS: ICD devices of four different manufacturers, incorporated in a thorax phantom, were transported in a Piper Dakota Aircraft with ICAO type designator P28B during several flights. The devices under test were programmed to the most sensitive settings for detection of electromagnetic signals from their environment. After the final flight the devices under test were interrogated with the dedicated programmers in order to analyze the number of tachycardias detected. RESULTS: Cumulative registration time of the devices under test was 11,392 min, with a mean of 2848 min per device. The registration from each one of the devices did not show any detectable "tachycardia" or subsequent inappropriate device therapy. This indicates that no external signals, which could be originating from electromagnetic fields from the aircraft's avionics, were detected by the devices under test. CONCLUSION: During transport in the cockpit of a single-engine fixed-wing aircraft, the tested ICDs did not show any signs of being affected by electromagnetic fields originating from the avionics of the aircraft. This current study indicates that EMI is not a potential safety issue for transportation of passengers with an ICD implanted in a single-engine fixed-wing aircraft.de Rotte AAJ, van der Kemp P, Mundy PA, Rienks R, de Rotte AA. Electromagnetic interference in implantable defibrillators in single-engine fixed-wing aircraft. Aerosp Med Hum Perform. 2017; 88(1):52-55.

Homelessness among problem drug users: prevalence, risk factors and trigger events.

The present paper uses data from a prospective cohort study of 877 problem drug users entering treatment in Scotland to extend knowledge of homelessness and drug misuse in three important respects: First, the prevalence of homelessness among problem drug users is investigated; secondly, key risk factors for homelessness among problem drug users are identified; and thirdly, trigger events associated with movements into or out of homelessness by problem drug users over time are explored. Data were collected during two waves of interviewing which were conducted 8 months apart. Thirty-six per cent of problem drug users entering treatment were homeless at either or both interviews, a prevalence rate that is at least seven times greater than among the general population. Whilst many of the risk factors found to be associated with homelessness are common to homeless people in general, at least one homelessness risk factor - recent drug injection [OR = 1.40; 95% confidence interval (CI) = 1.01-1.96]- is clearly specific to those who take drugs. Movements into homelessness among problem drug users were associated with recently losing residency of children (OR = 2.28; 95% CI = 1.27-4.08), other recent family problems (OR = 1.88; 95% CI = 1.21-2.94) and worsening general health (OR = 2.17; 95% CI = 1.15-4.09). Movements out of homelessness were associated with not having recent family problems (OR = 0.43; 95% CI = 0.24-0.79). The findings provide empirical support for the good practice guidelines now being published by various UK Government departments, but also suggest that the relatives of problem drug users should be offered increased assistance to help them deal with the many stresses that having a drug-dependent family member can bring.

Hemodynamic deterioration precedes onset of ventricular tachyarrhythmia after Heartmate II implantation.

BACKGROUND: Early postoperative ventricular tachyarrhythmia (PoVT) after left ventricular assist device (LVAD) implantation are common and associated with higher mortality-rates. At present, there is no data on initiation of these PoVT and the role of alterations in cardiac hemodynamics. CASE PRESENTATION: A LVAD was implanted in a patient with end-stage heart failure due to a ischemic cardiomyopathy. Alterations in cardiac rhythm and hemodynamics preceding PoVT-episodes during the first five postoperative days were examined by using continuous recordings of cardiac rhythm and various hemodynamic parameters. All PoVT (N=120) were monomorphic, most often preceded by short-long-short-sequences or regular SR and initiated by ventricular runs. Prior to PoVT, mean arterial pressure decreased; heart rate and ST-segments deviations increased. CONCLUSIONS: PoVT are caused by different underlying electrophysiological mechanisms. Yet, they are all monomorphic and preceded by hemodynamic deterioration due to myocardial ischemia.

Electromagnetic interference in pacemakers in single-engine fixed-wing aircraft: a European perspective.

BACKGROUND: The aim of this study is to evaluate the possible interference by avionics with cardiac pacemakers of aircrew or passengers/patients in single-engine fixed-wing aircraft. Pacemakers which are implanted in patients are in part electromagnetic sensors and can be subject to interference from various external electromagnetic sources. Although modern (chip-based) pacemakers are effectively shielded from electromagnetic interference (EMI), the magnitude of electromagnetic radiation in cockpits of general aviation aircraft is higher and of a different nature than experienced in daily life. An increasing number of pacemaker-bearing individuals are being transported by air. However, the possible EMI with modern types of pacemakers during flight has not been investigated until now. METHOD: In order to evaluate the effect of EMI on five modern types of pacemakers in the cockpit environment of a single-engine fixed-wing aircraft, we have subjected the pacemakers, each implanted into an artificial thorax, to a series of test flights. Each pacemaker was equipped with data logging capabilities which were used for detection of possible EMI. After each flight, the pacemakers were examined by means of the dedicated programmers. In addition, two single lead ventricular pacemakers (VVI) were analyzed by means of beat-to-beat Holter recordings during two separate flights. This enabled an exact analysis of pacemaker function and of possible EMI. RESULTS: No effect of EMI could be detected in any of the pacemakers by interrogating their internal counters after the test flights. In addition, no signs of EMI could be detected on the Holter recordings of the VVI pacemakers. CONCLUSION: We conclude that modern pacemakers are unaffected by EMI in the cockpit environment of single-engine fixed-wing aircraft.

Agricultural science in the wild: a social network analysis of farmer knowledge exchange.

Responding to demands for transformed farming practices requires new forms of knowledge. Given their scale and complexity, agricultural problems can no longer be solved by linear transfers in which technology developed by specialists passes to farmers by way of extension intermediaries. Recent research on alternative approaches has focused on the innovation systems formed by interactions between heterogeneous actors. Rather than linear transfer, systems theory highlights network facilitation as a specialized function. This paper contributes to our understanding of such facilitation by investigating the networks in which farmers discuss science. We report findings based on the study of a pastoral farming experiment collaboratively undertaken by a group of 17 farmers and five scientists. Analysis of prior contact and alter sharing between the group's members indicates strongly tied and decentralized networks. Farmer knowledge exchanges about the experiment have been investigated using a mix of quantitative and qualitative methods. Network surveys identified who the farmers contacted for knowledge before the study began and who they had talked to about the experiment by 18 months later. Open-ended interviews collected farmer statements about their most valuable contacts and these statements have been thematically analysed. The network analysis shows that farmers talked about the experiment with 192 people, most of whom were fellow farmers. Farmers with densely tied and occupationally homogeneous contacts grew their networks more than did farmers with contacts that are loosely tied and diverse. Thematic analysis reveals three general principles: farmers value knowledge delivered by persons rather than roles, privilege farming experience, and develop knowledge with empiricist rather than rationalist techniques. Taken together, these findings suggest that farmers deliberate about science in intensive and durable networks that have significant implications for theorizing agricultural innovation. The paper thus concludes by considering the findings' significance for current efforts to rethink agricultural extension.

Semiquantitative multi-analysis of plasma obtained from Romney lambs (Ovis aries) by inductively coupled plasma mass spectrometry, and the classification according to feed type.

The establishment of a classification system for domestic animals on consumed feed stuff is thought to be important from both a hygiene and market point of view. We collected plasma samples of Romney lambs (Ovis aries) which were fed one of the following: a herb-clover mix (n=10) which included chicory, red clover, white clover and plantain; a plant-grass mix (n=10) which included plantain, ryegrass and white clover; or a grass mix (n=10) which included ryegrass and white clover. A total of 20 elements in plasma samples obtained from the lambs were analyzed using inductively coupled plasma mass spectrometry. The data were then analyzed by principal component analysis. The lambs were divided into three groups on a score plot depending on the different feed conditions. Furthermore, discriminant analyses of the elements were examined, using linear discriminant analysis with forward stepwise regression. This discriminant function correctly classified the samples from each group. The accuracy of classification of each group, as shown by 10-fold cross-validation, proved the effectiveness of the established discriminant function. It is concluded that using linear discriminant analysis might be a useful tool for the validation of elements from plasma in lambs grown in different conditions.

The contribution of rate adaptive pacing with single or dual sensors to health-related quality of life.

AIMS: The characteristics of sensors to perform rate adaptive pacing are well established but whether their contribution improves health-related quality of life (QoL) remains disputable. To compare the effects on QoL with an integrated dual sensor [minute ventilation (MV) and acceleration, TT sensor] with a single MV sensor, and with no rate adaptive pacing. METHODS AND RESULTS: This Dutch multi centre, prospective, single- (patient) blind study was performed in patients after first pacemaker (PM) implant for sick sinus syndrome or AV block. After a 3-month 'sensor off'-period following DDD PM implantation, where the latter 2 months permitted the MV sensor to learn the intrinsic rhythm, a 2-month period of DDDR with TT sensor or 2 months of DDDR with MV sensor, subsequently the two modes were crossed over. Quality of life was determined with Aquarel, the disease-specific instrument for PM patients. Heart rate, percentages of sensor driven and intrinsic rhythm were retrieved from PM memories. Sixty-four patients completed the 7-month study. In sick sinus patients, percentages of sensor-driven pacing occurred significantly more frequently than in AV block patients After implant QoL improved significantly: before 71.3 and after 83.5% (P < 0.001) measured with Aquarel and in 3 of 9 SF-36 scales, but no significant additive QoL benefit with dual or MV sensor pacing was observed. Pacing diagnosis, percentages of rate adaptive pacing, and heart rate influencing medication did not influence this result. CONCLUSION: Pacemaker implantation strongly improves QoL, but neither single- nor dual- sensor-driven pacing offered additional improvement in QoL during the initial 8 months after the first PM implant.

Heart rate control via vagus nerve stimulation.

Objectives. There is ample and well-established evidence that direct electrical stimulation of the vagus nerve can change heart rate in animals and humans. Since tachyarrhythmias cannot always be controlled through medication, we sought, in this pilot study, to elucidate whether a clinical implantable lead system that is used in cervical vagus nerve stimulation therapy (VNS therapy) also can be used for control of heart rate, and tachycardia in particular. Materials and Methods. Experiments were carried out in three pigs (weight 21-26 kg) under general anesthesia. The right and left vagus nerves in the neck region were exposed by dissection, and bipolar, multiturn, helical, silicone leads were wrapped around the vagus nerves. Stimulation was applied by an external device with multivariable settings: frequency 10-100 Hz, pulse duration 100-700 µsec; delay 0-0.5 msec; current 0.5-14 mA. Measurements were performed under normal sinus rhythm (RR-interval 501 ± 30 msec) and during isoprenaline-induced tachycardia (RR-interval 284 ± 11 msec). Results. VNS, under optimal pacing conditions (100 Hz; 5 mA; 0.2 msec; 70 msec delay), in an electrocardiogram-triggered (ECG-triggered) pacing mode, increased RR-intervals by approximately 40%, irrespective of the duration of the RR-interval preceding VNS. The maximum effect on heart rate was established within approximately 5 sec after the onset of stimulation and was reversible and reproducible. No differences were found between stimulation of the right or left vagus nerve. Conclusion. VNS can be used effectively and rapidly to decrease heart rate, in acute settings, when connected to an external pacing system. Future devices that are fully implantable may be used for nonpharmacological treatment of illnesses in which tachycardia results in deterioration of cardiac function.