Sigmoid Neural Transfer Function Realised by Percolation

An experiment using the phenomenon of percolation has been conducted to demonstrate the implementation of neural functionality (summing and sigmoid transfer). A simple analog approximation to digital percolation is implemented. The device consists of a piece of amorphous silicon with stochastic bit-stream optical inputs, in which a current percolating from one end to the other defines the neuron output, also in the form of a stochastic bit stream. Preliminary experimental results are presented

Modern pollution signals in sediments from Windermere, NW England, determined by micro-XRF and lead isotope analysis

High resolution geochemical (Itrax micro-XRF and wavelength dispersive XRF) data, radiochronology (210Pb and 137Cs analyses) and ultra-high precision double-spike lead isotope measurements from lacustrine sediment cores are used in combination with historical research of former mining landscapes to investigate modern pollution signals in sediments from Windermere, the largest lake in the English Lake District. The sediment record suggests that while most element concentrations have been stable, there has been a significant increase since the 1930s in lead, zinc and copper concentrations. Double-spike lead isotope measurements reveal a mixture of natural lead, and three major contributory sources of anthropogenic (industrial) lead, comprising gasoline lead, coal combustion lead (from coal-fired steam ships) and lead derived from Carboniferous Pb–Zn mineralisation (mining activities). A number of up-system sediment traps have limited the amount of mining related heavy metals entering Windermere, and as a result, periods of metal workings do not correlate with peaks in heavy metals. Increases could also be due to flood-induced metal inwash or weathering of bedrock in the catchment. Application of these non-destructive and high precision analytical techniques provides new insights into the pollutant depositional history of Windermere

A 500 year sediment lake record of anthropogenic and natural inputs to Windermere (English Lake District) using double-spike lead isotopes, radiochronology, and sediment microanalysis

A high-resolution record of pollution is preserved in recent sediments from Windermere, the largest lake in the English Lake District. Data derived from X-ray core scanning (validated against wavelength dispersive X-ray fluorescence), radiochronological techniques (210Pb and 137Cs) and ultrahigh precision, double-spike mass spectrometry for lead isotopes are combined to decipher the anthropogenic inputs to the lake. The sediment record suggests that while most element concentrations have been stable, there has been a significant increase in lead, zinc, and copper concentrations since the 1930s. Lead isotope down-core variations identify three major contributory sources of anthropogenic (industrial) lead, comprising gasoline lead, coal combustion lead (most likely source is coal-fired steam ships), and lead derived from Carboniferous Pb–Zn mineralization (mining activities). Periods of metal workings do not correlate with peaks in heavy metals due to the trapping efficiency of up-system lakes in the catchment. Heavy metal increases could be due to flood-induced metal inwash after the cessation of mining and the weathering of bedrock in the catchment. The combination of sediment analysis techniques used provides new insights into the pollutant depositional history of Windermere and could be similarly applied to other lake systems to determine the timing and scale of anthropogenic inputs

Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

Photocatalytic generation of phosphoranyl radicals is fast emerging as an essential method for the generation of diverse and valuable radicals, typically via deoxygenation or desulfurization processes. This Perspective is a comprehensive evaluation of all studies using phosphoranyl radicals as tunable mediators in photoredox catalysis, highlighting how two distinct methods for phosphoranyl radical formation (radical addition and nucleophilic addition) can be used to generate versatile radical intermediates with diverse reactivity profiles

Acute insulin response following exercise and its association to lipid changes in sedentary African-American women

Sedentary African-American (AA) women are at increased risk of hypertension, dyslipidemias, metabolic syndrome, and impaired insulin response to exercise. The purpose of the study was to determine the effects of a single bout of aerobic exercise on fasting serum insulin and glucose concentrations following 1464 kJ (350 kcal) of exercise and to determine if this response was associated with serum lipid concentrations in overweight AA women. Premenopausal AA women (n = 11, mean ± SD, age = 32.5 ± 4.8 yr., BMI = 29.8 ± 4.8 kg·m-2, % fat = 35.6 ± 6.3, VO2peak = 21.5 ± 3.6 ml·kg-1·min-1, total cholesterol = 4.8 ± 0.6 mmol·L-1, triglycerides = 0.60 ± 0.2 mmol·L-1, HDLC = 3.3 ± 0.5 mg·dL-1) performed 1464 kJ (350 kcal) of treadmill exercise at 60%-70%VO2peak. Fasting plasma insulin and glucose concentrations were collected 24-h prior to, and immediately, 24-h, and 48 h following exercise. Fasting insulin concentration increased immediately following exercise (Baseline=77.1 ± 10.42 vs. Immediately=117.4 ± 15.28 μU·mL-1, 95%CI= 32.71, 47.89; P<0.05). The change in insulin concentration from 24-h pre- to 24-h post-exercise was correlated with BMI (r= 0.51), VO2peak (r= -0.47), and the change in lipoprotein lipase activity (r=0.37) (P<0.05 for all). In conclusion, in sedentary AA women, the insulin response immediately following exercise may be elevated, and is not suppressed below pre-exercise concentrations during the 48-h following exercise. The insulin response 24-h following exercise is modestly associated with markers of lipoprotein metabolism

Segmentation of Loops from Coronal EUV Images

We present a procedure which extracts bright loop features from solar EUV images. In terms of image intensities, these features are elongated ridge-like intensity maxima. To discriminate the maxima, we need information about the spatial derivatives of the image intensity. Commonly, the derivative estimates are strongly affected by image noise. We therefore use a regularized estimation of the derivative which is then used to interpolate a discrete vector field of ridge points ``ridgels'' which are positioned on the ridge center and have the intrinsic orientation of the local ridge direction. A scheme is proposed to connect ridgels to smooth, spline-represented curves which fit the observed loops. Finally, a half-automated user interface allows one to merge or split, eliminate or select loop fits obtained form the above procedure. In this paper we apply our tool to one of the first EUV images observed by the SECCHI instrument onboard the recently launched STEREO spacecraft. We compare the extracted loops with projected field lines computed from almost-simultaneously-taken magnetograms measured by the SOHO/MDI Doppler imager. The field lines were calculated using a linear force-free field model. This comparison allows one to verify faint and spurious loop connections produced by our segmentation tool and it also helps to prove the quality of the magnetic-field model where well-identified loop structures comply with field-line projections. We also discuss further potential applications of our tool such as loop oscillations and stereoscopy.Comment: 13 pages, 9 figures, Solar Physics, online firs

Enhanced histamine-induced itch in diacylglycerol kinase iota knockout mice

Subsets of small-diameter dorsal root ganglia (DRG) neurons detect pruritogenic (itch-causing) and algogenic (pain-causing) stimuli and can be activated or sensitized by chemical mediators. Many of these chemical mediators activate receptors that are coupled to lipid hydrolysis and diacylglycerol (DAG) production. Diacylglycerol kinase iota (DGKI) can phos-phorylate DAG and is expressed at high levels in small-diameter mouse DRG neurons. Given the importance of these neurons in sensing pruritogenic and algogenic chemicals, we sought to determine if loss of DGKI impaired responses to itch- or pain-producing stimuli. Using male and female Dgki-knockout mice, we found that in vivo sensitivity to histamine—but not other pruritogens—was enhanced. In contrast, baseline pain sensitivity and pain sensitization following inflammatory or neuropathic injury were equivalent between wild type and Dgki-/- mice. In vitro calcium responses in DRG neurons to histamine was enhanced, while responses to algogenic ligands were unaffected by Dgki deletion. These data suggest Dgki regulates sensory neuron and behavioral responses to histamine, without affecting responses to other pruritogenic or algogenic agents

The effect of Ganges river basin irrigation on pre‐monsoon rainfall

The first experiment studying the effect of irrigation on pre-monsoon rainfall in India using a high-resolution convection-permitting model has been carried out. This study includes both short (3-day) experiments and month-long free-running simulations, enabling investigation of the effect of irrigation on mesoscale circulations and associated rainfall. In the pre-monsoon, it is found that irrigation increases rainfall in our simulations. Intriguingly, the rainfall increase found in the high-resolution model mostly occurs on the mountains near the irrigation rather than over the irrigated region itself. This is because our applied irrigation is in low-lying regions, and so it enhances the mountain-valley flows leading to enhancement of diurnally driven orographic rainfall. Because Ganges basin irrigation occurs near mountains which already have some of the highest rainfall rates in the world, and which are subject to flash flooding and landslides, this has significant implications for hazards in mountainous regions during the pre-monsoon and early monsoon period

Search for Possible Variation of the Fine Structure Constant

Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different methods of a search for possible variations of fundamental constants are compared and those related to optical measurements are considered in detail.Comment: An invited talk at HYPER symposium (Paris, 2002

Spinal macrophages resolve nociceptive hypersensitivity after peripheral injury

Peripheral nerve injury induces long-term pro-inflammatory responses in spinal cord glial cells that facilitate neuropathic pain, but the identity of endogenous cells that resolve spinal inflammation has not been determined. Guided by single-cell RNA sequencing (scRNA-seq), we found that MRC1+ spinal cord macrophages proliferated and upregulated the anti-inflammatory mediator Cd163 in mice following superficial injury (SI; nerve intact), but this response was blunted in nerve-injured animals. Depleting spinal macrophages in SI animals promoted microgliosis and caused mechanical hypersensitivity to persist. Conversely, expressing Cd163 in spinal macrophages increased Interleukin 10 expression, attenuated micro- and astrogliosis, and enduringly alleviated mechanical and thermal hypersensitivity in nerve-injured animals. Our data indicate that MRC1+ spinal macrophages actively restrain glia to limit neuroinflammation and resolve mechanical pain following a superficial injury. Moreover, we show that spinal macrophages from nerve-injured animals mount a dampened anti-inflammatory response but can be therapeutically coaxed to promote long-lasting recovery of neuropathic pain