Dynamic supply chain alignment:a new business model for peak performance in enterprise supply chains across all geographies

Dynamic supply chain alignment: a new business model for peak performance in enterprise supply chains across all geographies John Gattorna and friends, Farnham, Gower Publishing, 2009, 440pp., £60, ISBN 978-0-566-08822-3.

Appetite regulatory mechanisms and food intake in mice are sensitive to mismatch in diets between pregnancy and postnatal periods

Human and animal studies suggest that obesity in adulthood may have its origins partly during prenatal development. One of the underlying causes of obesity is the perturbation of hypothalamic mechanisms controlling appetite. We determined mRNA levels of genes that regulate appetite, namely neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and the leptin receptor isoform Ob-Rb, in the hypothalamus of adult mouse offspring from pregnant dams fed a protein-restricted diet, and examined whether mismatched post-weaning high-fat diet altered further expression of these gene transcripts. Pregnant MF1 mice were fed either normal protein (C, 18% casein) or protein-restricted (PR, 9% casein) diet throughout pregnancy. Weaned offspring were fed to adulthood a high-fat (HF; 45% kcal fat) or standard chow (21% kcal fat) diet to generate the C/HF, C/C, PR/HF and PR/C groups. Food intake and body weight were monitored during this period. Hypothalamic tissues were collected at 16 weeks of age for analysis of gene expression by real time RT-PCR. All HF-fed offspring were observed to be heavier vs. C groups regardless of the maternal diet during pregnancy. In the PR/HF males, but not in females, daily energy intake was reduced by 20% vs. the PR/C group (p <0.001). In PR/HF males, hypothalamic mRNA levels were lower vs. the PR/C group for NPY (p <0.001) and Ob-Rb (p <0.05). POMC levels were similar in all groups. In females, mRNA levels for these transcripts were similar in all groups. Our results suggest that adaptive changes during prenatal development in response to maternal dietary manipulation may have long-term sex-specific consequences on the regulation of appetite and metabolism following post-weaning exposure to an energy-rich nutritional environment. © 2008 Elsevier B.V. All rights reserved.

Contact time periods in immunological synapse

This paper resolves the long standing debate as to the proper time scale τ of the onset of the immunological synapse bond, the noncovalent chemical bond defining the immune pathways involving T cells and antigen presenting cells. Results from our model calculations show τ to be of the order of seconds instead of minutes. Close to the linearly stable regime, we show that in between the two critical spatial thresholds defined by the integrin:ligand pair (Δ2∼ 40-45 nm) and the T-cell receptor TCR:peptide-major-histocompatibility-complex pMHC bond (Δ1∼ 14-15 nm), τ grows monotonically with increasing coreceptor bond length separation δ (= Δ2-Δ1∼ 26-30 nm) while τ decays with Δ1 for fixed Δ2. The nonuniversal δ-dependent power-law structure of the probability density function further explains why only the TCR:pMHC bond is a likely candidate to form a stable synapse.

Picosecond pulse amplification up to a peak power of 42 W by a quantum-dot tapered optical amplifier and a mode-locked laser emitting at 1.26 μm

We experimentally study the generation and amplification of stable picosecond-short optical pulses by a master oscillator power-amplifier configuration consisting of a monolithic quantum-dot-based gain-guided tapered laser and amplifier emitting at 1.26 μm without pulse compression, external cavity, gain-or Q-switched operation. We report a peak power of 42 W and a figure-of-merit for second-order nonlinear imaging of 38.5 W2 at a repetition rate of 16 GHz and an associated pulse width of 1.37 ps.

Linear dispersive pre-defined peak amplitude modulation of spectrally modulated airy-based pulses

Spectrally modulated Airy-based pulses peak amplitude modulation (PAM) in linear dispersive media is investigated, designed, and numerically simulated. As it is shown here, it is possible to design the spectral modulation of the initial Airy-based pulses to obtain a pre-defined PAM profile as the pulse propagates. Although optical pulses self-amplitude modulation is a well-known effect under non-linear propagation, the designed Airy-based pulses exhibit PAM under linear dispersive propagation. This extraordinary linear propagation property can be applied in many kinds of dispersive media, enabling its use in a broad range of experiments and applications. © 2013 Optical Society of America.

High sensitivity biosensor based on dual-peak LPG sensitised by light cladding etching

We demonstrate a high sensitivity biosensor by fine tailoring mode dispersion and sensitivity of dual-peak LPGs using light-cladding-etching method. The etched device has been used to detect concentration of Hemoglobin protein in sugar solution, showing a sensitivity as high as 20nm/1%.

Fracture and viscoelastic properties of asphalt binders during fatigue and rest periods

Viscoelastic asphalt binder plays an important role in bonding individual aggregate particles and contributes to the durability and stability of asphalt pavement. When asphalt binder is subjected to cyclic loading, deformation and fracture may develop simultaneously within it, leading to the deterioration of material properties and eventually fatigue failure. Research has found that some degree of recovery may develop if rest periods are applied after fatigue deterioration. However, it is not clear whether such recovery is caused by fracture healing, viscoelastic recovery, or both. This paper presents an analysis to differentiate the contributions of fracture healing and viscoelastic recovery to the asphalt binder during rest periods. It also evaluates the damage caused by deformation and fracture during a fatigue process. It is found that viscoelastic recovery plays an important role in the instant increase in the dynamic shear modulus at the beginning of the rest period. The effect of fracture healing on dynamic shear modulus recovery is more dominant in the long term. A healing index is developed based only on the fracture healing of asphalt binder, excluding the effect of viscoelastic recovery. It can be used to evaluate the true healing properties of different asphalt binders. Copyright © 2014 by ASTM International.

Characterization of viscoplastic yielding of asphalt concrete

A temperature and strain rate dependent yield surface model was proposed to characterize the viscoplastic yielding of asphalt concrete. Laboratory tests were conducted on specimens that have two binders, two air void contents, and three aging periods. Strain decomposition was performed to obtain viscoplastic strain and stress-pseudostrain curves were constructed to determine the model parameters accurately and efficiently. Results indicate that a stiffer asphalt concrete has greater cohesion and strain hardening amplitude, both of which decline as temperature increases or strain rate decreases. The temperature and strain rate factors of the yield surface can be accurately determined solely by the peak stress of the strength tests. © 2013 Elsevier Ltd. All rights reserved.

Arthur Lindo Patterson, his function and element preferences in early crystal structures

In 1934, Arthur Lindo Patterson showed that a map of interatomic vectors is obtainable from measured X-ray diffraction data without phase information. Such maps were interpretable for simple crystal structures, but proliferation and overlapping of peaks caused confusion as the number of atoms increased. Since the peak height of a vector between two particular atoms is related to the product of their atomic numbers, a complicated structure could effectively be reduced to a simple one by including just a few heavy atoms (of high atomic number) since their interatomic vectors would stand out from the general clutter. Once located, these atoms provide approximate phases for Fourier syntheses that reveal the locations of additional atoms. Surveys of small-molecule structures in the Cambridge Structural Database during the periods 1936-1969, when Patterson methods were commonly used, and 1980-2013, dominated by direct methods, demonstrate large differences in the abundance of certain elements. The moderately heavy elements K, Rb, As and Br are the heaviest elements in the structure more than 3 times as often in the early period than in the recent period. Examples are given of three triumphs of the heavy atom method and two initial failures that had to be overcome. © 2014 © 2014 Taylor & Francis.

Reductions of peak-to-average power ratio and optical beat interference in cost-effective OFDMA-PONs

The peak-to-average power ratio (PAPR) and optical beat interference (OBI) effects are examined thoroughly in orthogonal frequency-division multiplexing access (OFDMA)-passive optical networks (PONs) at a signal bit rate up to ∼ 20 Gb/s per channel using cost-effective intensity-modulation and direct-detection (IM/DD). Single-channel OOFDM and upstream multichannel OFDM-PONs are investigated for up to six users. A number of techniques for mitigating the PAPR and OBI effects are presented and evaluated including adaptive-loading algorithms such as bit/power-loading, clipping for PAPR reduction, and thermal detuning (TD) for the OBI suppression. It is shown that the bit-loading algorithm is a very efficient PAPR reduction technique by reducing it at about 1.2 dB over 100 Km of transmission. It is also revealed that the optimum method for suppressing the OBI is the TD + bit-loading. For a targeted BER of 1 × 10-3, the minimum allowed channel spacing is 11 GHz when employing six users. © 2013 Springer Science+Business Media New York.

Quantum-dot saturable absorber and Kerr lens mode-locked Yb:KGW laser with >300 kW of peak power

Dual action of quantum-dot saturable absorber and Kerr lens mode locking of a diode-pumped Yb:KGW laser was demonstrated. The laser delivered 105 fs pulses with 2.5 W of average power and >300 kW of peak power.