The effect of reduced tillage on nitrous oxide emissions of silt loam soils

The effect of reduced tillage (RT) on nitrous oxide (N₂O) emissions of soils from fields with root crops under a temperate climate was studied. Three silt loam fields under RT agriculture were compared with their respective conventional tillage (CT) field with comparable crop rotation and manure application. Undisturbed soil samples taken in September 2005 and February 2006 were incubated under laboratory conditions for 10 days. The N₂O emission of soils taken in September 2005 varied from 50 to 1,095 μg N kg⁻¹ dry soil. The N₂O emissions of soils from the RT fields taken in September 2005 were statistically (P < 0.05) higher or comparable than the N₂O emissions from their respective CT soil. The N₂O emission of soils taken in February 2006 varied from 0 to 233 μg N kg⁻¹ dry soil. The N₂O emissions of soils from the RT fields taken in February 2006 tended to be higher than the N₂O emissions from their respective CT soil. A positive and significant Pearson correlation of the N₂O–N emissions with nitrate nitrogen (NO₃ ⁻–N) content in the soil was found (P < 0.01). Leaving the straw on the field, a typical feature of RT, decreased NO₃ ⁻–N content of the soil and reduced N₂O emissions from RT soils.     

Use of a stand-alone pressure plate for the objective evaluation of forelimb symmetry in sound ponies at walk and trot

Subtle lameness in horses may be difficult to diagnose and methods to evaluate lameness objectively are useful when equine clinicians fail to reach a consensus. The aim of this study was to determine whether equine pressure plate measurements are repeatable when used to calculate forelimb loading (peak vertical pressure [PVP], peak vertical force [PVF], vertical impulse [VI]) and symmetry ratios, and to establish if these data are similar to the ‘gold standard’ force plate values. Since plate dimensions are relatively small, ponies were used to enable recordings to be taken from both forelimbs in one trial. Five sound ponies were walked and trotted over a pressure plate which was embedded in a custom-made runway. For each pony, five valid trials were recorded during two different days. A trial was considered valid if complete prints of both fore hooves were recorded consecutively and if velocity was within a preset range.The PVP, PVF and VI values showed an acceptable variability (CV ? 16%), with PVF (130% of bodyweight [BW], n = 5) similar to previously reported force plate data (128% BW, n = 48). Mean symmetry ratios appeared to be high (>95%) and showed a low variability (CV < 5%). The stand-alone pressure plate permitted adequate registration of forelimb PVF, VI and limb symmetry with a high level of precision in sound ponies.     

Functional adaptation through changes in regional biochemical characteristics during maturation of equine superficial digital flexor tendons

OBJECTIVE: To quantify and compare biochemical characteristics of the extracellular matrix (ECM) of specimens harvested from tensional and compressive regions of the superficial digital flexor tendon (SDFT) of horses in age classes that include neonates to mature horses. SAMPLE POPULATION: Tendon specimens were collected on postmortem examination from 40 juvenile horses (0, 5, 12, and 36 months old) without macroscopically visible signs of tendonitis. PROCEDURE: Central core specimens of the SDFT were obtained with a 4-mm-diameter biopsy punch from 2 loaded sites, the central part of the mid-metacarpal region and the central part of the mid-sesamoid region. Biochemical characteristics of the collagenous ECM content (ie, collagen, hydroxylysylpyridinoline crosslink, and pentosidine crosslink concentrations and percentage of degraded collagen) and noncollagenous ECM content (percentage of water and glycosaminoglycans, DNA, and hyaluronic acid concentrations) were measured. RESULTS: The biochemical composition of equine SDFT was not homogeneous at birth with respect to DNA, glycosaminoglycans, and pentosidine concentrations. For most biochemical variables, the amounts present at birth were dissimilar to those found in mature horses. Fast and substantial changes in all components of the matrix occurred in the period of growth and development after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Unlike cartilage, tendon tissue is not biochemically blank (ie, homogeneous) at birth. However, a process of functional adaptation occurs during maturation that changes the composition of equine SDFT from birth to maturity. Understanding of the maturation process of the juvenile equine SDFT may be useful in developing exercise programs that minimize tendon injuries later in life that result from overuse.     

Interactions of butyric acid- and acetic acid-treated Salmonella with chicken primary cecal epithelial cells in vitro

In vitro studies of the interaction between pathogenic bacteria and the chicken intestinal epithelium are hampered by the lack of a host- and tissue-specific in vitro model. Therefore, a reproducible method for isolation and cultivation of chicken primary cecal epithelial cells was developed. Cecal crypts were isolated and cultured in vitro to form a semiconfluent layer of epithelial cells. Incubation of Salmonella enteritidis with these cells resulted in invasion. Pretreatment of the Salmonella bacteria with butyric acid resulted in a significant decrease of invasion of the bacteria in the chicken cecal epithelial cells, whereas pretreatment with acetic acid increased invasiveness. These interactions of S. enteritidis with primary chicken cecal epithelial cells were similar to the interactions with other epithelial cell types.     

Mapping soil Pb stocks and availability in mainland France combining regression trees with robust geostatistics

Maps of lead (Pb) stocks in soils and estimates of its availability are needed to assess risks of contamination. Stocks in soils of total and ethylenediamine tetraacetic acid (EDTA) extractable Pb, as well as Pb availability, assessed by EDTA/total Pb ratio, were measured and calculated to a depth of 30 cm with the French soil monitoring network at sites defined by a regular 16 × 16 km grid. Setting aside punctual anomalies by winsorizing, these properties were mapped using linear mixed models (LMM). LMMs combined conditional partitioning trees upon 5 predictors (pH, texture, parent material, land use, population density) with robust geostatistics to avoid distortion due to outlying values. Rather than selecting the fixed effects according to expert-knowledge, regression trees were used to account for explanatory variables in a single classification. This original method stressed both the necessity for a geostatistical component to complement regression tree models when spatial correlation is evident, and the usefulness of these trees to interpret maps. Pb stocks varied widely with peak concentrations and availability in densely populated areas. Lithology, texture and forestation also affected total Pb stocks. With regards to availability, forestation and pH appeared as key factors.     

Mutations in the DJ-1 gene associated with autosomal recessive early-onset parkinsonism

The DJ-1 gene encodes a ubiquitous, highly conserved protein. Here, we show that DJ-1 mutations are associated with PARK7, a monogenic form of human parkinsonism. The function of the DJ-1 protein remains unknown, but evidence suggests its involvement in the oxidative stress response. Our findings indicate that loss of DJ-1 function leads to neurodegeneration. Elucidating the physiological role of DJ-1 protein may promote understanding of the mechanisms of brain neuronal maintenance and pathogenesis of Parkinson's disease.     

The spectral-element method,Beowulf computing,and global seismology

The propagation of seismic waves through Earth can now be modeled accurately with the recently developed spectral-element method. This method takes into account heterogeneity in Earth models, such as three-dimensional variations of seismic wave velocity, density, and crustal thickness. The method is implemented on relatively inexpensive clusters of personal computers, so-called Beowulf machines. This combination of hardware and software enables us to simulate broadband seismograms without intrinsic restrictions on the level of heterogeneity or the frequency content.     

Virtual water: Virtuous impact? The unsteady state of virtual water

“Virtual water,” water needed for crop production, is now being mainstreamed in the water policy world. Relying on virtual water in the form of food imports is increasingly recommended as good policy for water-scarce areas. Virtual water globalizes discussions on water scarcity, ecological sustainability, food security and consumption. Presently the concept is creating much noise in the water and food policy world, which contributes to its politicization. We will argue that the virtual water debate is also a “real water” and food and agricultural policy debate and hence has political effects. Decisions about food strategies and resource allocation play out on the national political economy, benefiting some while harming others. Therefore, a policy choice for virtual water is not politically neutral. “Real␣water” interventions are, likewise, inspired by economic as well as political considerations like control of the countryside, geopolitical strategy, and food sovereignty (independence from international political conditionality and market uncertainties). To illustrate these ideas, we look into case studies of Egypt and the State of Punjab in India. In India, a debate on the merits and demerits of a virtual water strategy is now emerging. In Egypt, which switched to food imports in the early 1970s, a long-standing taboo on debating virtual water is now being relaxed.

Coronavirus main proteinase (3CLpro) structure: basis for design of anti-SARS drugs

A novel coronavirus has been identified as the causative agent of severe acute respiratory syndrome (SARS). The viral main proteinase (Mpro, also called 3CLpro), which controls the activities of the coronavirus replication complex, is an attractive target for therapy. We determined crystal structures for human coronavirus (strain 229E) Mpro and for an inhibitor complex of porcine coronavirus [transmissible gastroenteritis virus (TGEV)] Mpro, and we constructed a homology model for SARS coronavirus (SARS-CoV) Mpro. The structures reveal a remarkable degree of conservation of the substrate-binding sites, which is further supported by recombinant SARS-CoV Mpro-mediated cleavage of a TGEV Mpro substrate. Molecular modeling suggests that available rhinovirus 3Cpro inhibitors may be modified to make them useful for treating SARS.