Coupling between neuronal firing, field potentials, and FMRI in human auditory cortex

Functional magnetic resonance imaging (fMRI) is an important tool for investigating human brain function, but the relationship between the hemodynamically based fMRI signals in the human brain and the underlying neuronal activity is unclear. We recorded single unit activity and local field potentials in auditory cortex of two neurosurgical patients and compared them with the fMRI signals of 11 healthy subjects during presentation of an identical movie segment. The predicted fMRI signals derived from single units and the measured fMRI signals from auditory cortex showed a highly significant correlation (r = 0.75, P < 10(-47)). Thus, fMRI signals can provide a reliable measure of the firing rate of human cortical neurons.     

Long-term growth, water consumption and yield of date palm as a function of salinity

Actual measurements of water uptake and use, and the effect of water quality considerations on evapotranspiration (ET), are indispensable for understanding root zone processes and for the development of predictive plant growth models. The driving hypothesis of this research was that root zone stress response mechanisms in perennial fruit tree crops is dynamic and dependent on tree maturity and reproductive capability. This was tested by investigating long-term ET, biomass production and fruit yield in date palms (Phoenix dactylifera L., cv. Medjool) under conditions of salinity. Elevated salinity levels in the soil solution were maintained for 6 years in large weighing-drainage lysimeters by irrigation with water having electrical conductivity (EC) of 1.8, 4, 8 and 12 dS m⁻¹. Salinity acted dynamically with a long-term consequence of increasing relative negative response to water consumption and plant growth that may be explained either as an accumulated effect or increasing sensitivity. Sensitivity to salinity stabilized at the highest measured levels after the trees matured and began producing fruit. Date palms were found to be much less tolerant to salinity than expected based on previous literature. Trees irrigated with low salinity (EC = 1.8 dS m⁻¹) water were almost twice the size (based on ET and growth rates) than trees irrigated with EC = 4 dS m⁻¹ water after 5 years. Fruit production of the larger trees was 35-50% greater than for the smaller, salt affected, trees. Long term irrigation with very high EC of irrigation water (8 and 12 dS m⁻¹) was found to be commercially impractical as growth and yield were severely reduced. The results raise questions regarding the nature of mechanisms for salinity tolerance in date palms, indicate incentives to irrigate dates with higher rather than lower quality water, and present a particular challenge for modelers to correctly choose salinity response functions for dates as well as other perennial crops.     

Long-term study of above- and below-ground biomass production in relation to nitrogen and carbon accumulation dynamics in a grey alder (Alnus incana (L.) Moench) plantation on former agricultural land

In the Northern and Baltic countries, grey alder is a prospective tree species for short-rotation forestry. Hence, knowledge about the functioning of such forest ecosystems is critical in order to manage them in a sustainable and environmentally sound way. The 17-year-long continuous time series study is conducted in a grey alder plantation growing on abandoned agricultural land. The results of above- and below-ground biomass and production of the 17-year-old stand are compared to the earlier published respective data from the same stand at the ages of 5 and 10 years. The objectives of the current study were to assess (1) above-ground biomass (AGB) and production; (2) below-ground biomass: coarse root biomass (CRB), fine root biomass (FRB) and fine root production (FRP); (3) carbon (C) and nitrogen (N) accumulation dynamics in grey alder stand growing on former arable land. The main results of the 17-year-old stand were as follows: AGB 120.8 t ha^?1; current annual increment of the stem mass 5.7 t ha year^?1; calculated CRB 22.3 t ha^?1; FRB 81 ± 10 g m^?2; nodule biomass 31 ± 19 g m^?2; fine root necromass 11 ± 2 g m^?2; FRP 53 g DM m^?2 year^?1; fine root turnover rate 0.54 year^?1; and fine root longevity 1.9 years. FRB was strongly correlated with the stand basal area and stem mass. Fine root efficiency was the highest at the age of 10 years; at the age of 17 years, it had slightly reduced. Grey alder stand significantly increased N and C_org content in topsoil. The role of fine roots for the sequestration of C is quite modest compared to leaf litter C flux.     

Nutrient use efficiency and harvest index of cassava decline as fertigation solution concentration increases

Response of cassava (Manihot esculenta Crantz) to fertigation as a form of nutrient delivery is unknown. The objectives of this study were to establish a balanced nutrition and to enhance agronomic nutrient use efficiency (ANUE) of cassava under fertigation. This study was conducted in the greenhouse and in the field. In both, the results showed a similar trend. There were six fertigation concentrations and three cassava varieties, selected for their duration of growth in the field. Shoot biomass of the long‐duration variety (Nalumino) was the highest, even though its dry root yield was the lowest (10.18 t ha^?1) among the varieties. In contrast, the medium‐duration variety (Kampolombo) produced the highest dry root yield (20.34 t ha^?1) and a lower shoot biomass. The highest root yield of the shortest‐duration variety (Mweru) was achieved at 200 mg N, 30 mg P, and 200 mg K L^?1 (155.0, 23.3, 155.0 kg N, P, K ha^?1), while Nalumino's was at 70 mg N, 7 mg P, and 70 mg K L^?1 (54.3, 5.4, 54.3 kg N, P, K ha^?1). ANUE and harvest index of these varieties declined as the fertigation concentrations increased. Additionally, the correlation between concentrations of N in the youngest fully expanded leaf (YFEL) blades and dry root yields was the lowest (R² = 0.5488), whereas P and K were R² = 0.7237 and R² = 0.8006, respectively, an indication that nutrient concentrations in the leaf, especially N, cannot easily be used to predict root yield. When cassava reaches nutrient sufficiency, mainly N, its accumulation in the leaf continues without significant increase in the root yield.     

Effects of resistant starch type III polymorphs on human colon microbiota and short chain fatty acids in human gut models

This study probed the possible effects of type III resistant starch (RS) crystalline polymorphism on RS fermentability by human gut microbiota and the short chain fatty acids production in vitro. Human fecal pH-controlled batch cultures showed RS induces an ecological shift in the colonic microbiota with polymorph B inducing Bifidobacterium spp. and polymorph A inducing Atopobium spp. Interestingly, polymorph B also induced higher butyrate production to levels of 0.79 mM. In addition, human gut simulation demonstrated that polymorph B promotes the growth of bifidobacteria in the proximal part of the colon and double their relative proportion in the microbiota in the distal colon. These findings suggest that RS polymorph B may promote large bowel health. While the findings are limited by study constraints, they do raise the possibility of using different thermal processing to delineate differences in the prebiotic capabilities of RS, especially its butryrogenicity in the human colon.     

Effect of soil moisture on the release of alachlor from alginate-based controlled-release formulations

The release of alachlor from controlled-release formulations (CRFs) based on alginate-montmorillonite matrices into aqueous polyethylene glycol (PEG) solutions of different concentrations and into a soil at different moisture contents was studied. In distilled water and in PEG-containing solutions displaying -0.1 MPa potential and up, the beads imbibe water and swell. The ensuing increase in weight is about 5%, and the increase in the bead's diameter is about 10%. At water potentials of -0.5 MPa and lower, loss of weight and shrinkage of the beads were observed. The changes in weight and diameter of the alginate-clay beads incubated in a Hamra loamy sand soil at 26.5% moisture content (w/w; -0.18 MPa) were similar to those observed in PEG solutions of >-0.5 MPa moisture potential. The weight and diameter losses observed in the drier soils (12.0 and 7.1% water content; -0.49 and -1.11 MPa) were similar to those in the more concentrated PEG solutions. A decrease in the rate of release of the active ingredient from the beads into soil was observed as the water potential decreased (drier soils). The release of the active ingredient from the investigated CRFs displayed a linear relationship to the square root of time, suggesting a diffusion-controlled-release rate. Data extracted from this relationship enabled the formulation of a mathematical model that correlates rate of release to water content.     

A COMPLETE MOBILE RADIOLOGY LABORATORY FOR LARGE ANIMAL FIELD WORK

Because of the lack of a large animal hospital in Israel, and the need to provide radiology service to equine and bovine patients, a complete radiology mobile laboratory for field work was built. The laboratory was constructed in a van-type automobile and is equipped with a condenser-discharge x-ray unit, a tabletop automatic processor, and a dark room facility. The qualities of each of the components and the operation of the laboratory are discussed.     

Expression of relaxin receptor LRG7, canine relaxin, and relaxin-like factor in the pelvic diaphragm musculature of dogs with and without perineal hernia

OBJECTIVES: To compare the expression of canine relaxin, relaxin-like factor (RLF), and relaxin receptors within the muscles of the pelvic diaphragm of dogs with perineal hernia (PH) and clinically normal dogs. STUDY DESIGN: In vivo comparative study. ANIMALS: Fifteen client-owned intact male dogs with PH were studied. Four mature intact male dogs with no evidence of perineal pathology served as controls. METHODS: Biopsy samples from the levator ani, coccygeus, and internal obturator muscles were obtained. RNA samples were reverse transcribed and analyzed by real-time PCR for the expression of canine relaxin receptor LRG7, relaxin, and RLF. RESULTS: Significantly higher expression levels of canine relaxin receptors occurred in the musculature of the pelvic diaphragm and internal obturator muscle in dogs with PH compared with normal dogs. Expression of canine RLF revealed no significant difference between dogs with PH and controls. The difference in the expression of canine relaxin between groups was not statistically significant. CONCLUSIONS: Relaxin receptor up-regulation occurs in the coccygeus, levator ani, and internal obturator muscles of dogs with PH. CLINICAL RELEVANCE: The higher expression of relaxin receptors within the muscles of the pelvic diaphragm in dogs with PH suggests that relaxin might play a role in the pathogenesis of PH. Atrophy of these muscles, which predisposes to PH, may be attributable to increased relaxin activity.