Effects of 34-year-old Pinus taeda and Eucalyptus grandis plantations on soil carbon and nutrient status in former miombo forest soils

There is a strong need in Mozambique to counteract decades of deforestation and forest degradation by planting new forests. Plantations of Pinus/Eucalyptus species and maintenance of mature miombo forests are activities supported by the REDD+ mechanism (Reducing Emissions from Deforestation and forest Degradation) in climate negotiations. This study examined the effects of first-rotation Pinus taeda L. (Loblolly pine) and Eucalyptus grandis Hill ex Maiden plantations (ca. 34 years old) on soil carbon status compared with adjacent dry miombo forest. At three study sites located in the Western Highlands of Manica Province, Mozambique, study plots with Pinus taeda, Eucalyptus grandis and mixed-deciduous miombo species were delineated. The selection criteria were (i) forest stand of first-rotation plantation of Pinus/Eucalyptus, located adjacent to miombo forest, (ii) plantations established on soils similar to miombo forest soils, and (iii) former land use similar to that at current miombo sites. Stocks of soil organic carbon (SOC), total nitrogen (N) and extractable phosphorus (P) were quantified. Soil pH (H2O), cation exchange capacity (CEC) and base saturation (BS) were measured in soil extracted with ammonium acetate. Plantations of P. taeda and E. grandis increased total SOC stocks (0-50 cm) and N stocks in the top 10 cm. Assuming steady state in the miombo stands, the estimated net stock change in soil carbon was 1.41 Mg ha-1 yr-1 in P. taeda and 1.53 Mg ha-1 yr-1 in E. grandis stands. Estimated N accumulation rate was 32 kg ha-1 yr-1 in P. taeda and E. grandis stands. Pinus taeda had no significant effect on extractable P, soil pH and BS, but had significantly higher CEC compared with miombo forest soil. Eucalyptus grandis decreased P stocks, but increased soil pH and BS. Overall, P. taeda and E. grandis plantation had a large impact on SOC in dry miombo forest and also affected soil acidity and soil nutrient status, except for total soil N stocks. These effects of tree plantation on soil reflected differences in management practices between miombo forest and plantations, with the latter being subjected to better protection against fires and illegal cutting

Feasibility Study of FPGA-Based Equalizer for 112-Gbit/s Optical Fiber Receivers

With ever increasing demands on spectral efficiency, complex modulation schemes are being introduced in fiber communication. However, these schemes are challenging to implement as they drastically increase the computational burden at the fiber receiver’s end. We perform a feasibility study of implementing a 16-QAM 112-Gbit/s decision directed equalizer on a state-of-the-art FPGA platform. An FPGA offers the reconfigurability needed to allow for modulation scheme updates, however, its clock rate is limited. For this purpose, we introduce a new phase correction technique to significantly relax the delay requirement on the critical phase-recovery feedback loop

37 Gbps transmission over 200 m of MMF using single cycle subcarrier modulation and a VCSEL with 20 GHz modulation bandwidth

We report transmission at 37.2 Gb/s over 200 m of multimode fibre using a directly modulated VCSEL operating at 850 nm, using 20 GHz modulation bandwidth

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

All-Optical Switching with the Nonlinear Optical Loop Mirror

This thesis deals with the theory and applications of the nonlinear optical loop mirror (NOLM). Novel methods to restore and filter optical data as well as generate high peak power optical pulses using the NOLM are demonstrated. Further more, new approaches for polarization indep endent demultiplexing and a fully polarization independent all-optical AND-gate are proposed and experimentally demonstrated. The NOLM has been widely employed as an ultrafast demultiplexing device with the potential of demultiplexing data at speeds beyond 1 Tbit/s. The nonlinear characteristics of the NOLM can also be utilized for other all-optical applications such as filtering and logic operations. The nonlinear transmission characteristic is used to substantially improve the extinction ratio of an optical data sequence and remove low intensity noise over a wide spectral range. The proposed filtering technique is also successfully employed in a chain of optical amplifiers to generate pulses with very high peak power. Several new schemes for performing polarization independent all optical switching using standard dispersion shifted fibers are also proposed and demonstrated. One scheme utilizes a birefringent element in a control power balanced propagation diversity NOLM. This control power balanced NOLM is shown not to suffer from control power induced crosstalk as the conventional NOLM does. Another scheme employs a dispersion shifted fiber with random birefringence and has the advantage of being polarization independent of both data and control signal, thus constituting a polarization independent AND-gate. Finally a scheme utilizing the optical Kerr effect in a polarization diversity loop is demonstrated. This scheme is not an interferometer which results in better stability than other NOLMs. In addition, a solution to make the NOLM insensitive to acoustical disturbances by rewinding the loop fiber is demonstrated

All-Optical Switching with the Nonlinear Optical Loop Mirror

This thesis deals with the theory and applications of the nonlinear optical loop mirror (NOLM). Novel methods to restore and filter optical data as well as generate high peak power optical pulses using the NOLM are demonstrated. Further more, new approaches for polarization indep endent demultiplexing and a fully polarization independent all-optical AND-gate are proposed and experimentally demonstrated. The NOLM has been widely employed as an ultrafast demultiplexing device with the potential of demultiplexing data at speeds beyond 1 Tbit/s. The nonlinear characteristics of the NOLM can also be utilized for other all-optical applications such as filtering and logic operations. The nonlinear transmission characteristic is used to substantially improve the extinction ratio of an optical data sequence and remove low intensity noise over a wide spectral range. The proposed filtering technique is also successfully employed in a chain of optical amplifiers to generate pulses with very high peak power. Several new schemes for performing polarization independent all optical switching using standard dispersion shifted fibers are also proposed and demonstrated. One scheme utilizes a birefringent element in a control power balanced propagation diversity NOLM. This control power balanced NOLM is shown not to suffer from control power induced crosstalk as the conventional NOLM does. Another scheme employs a dispersion shifted fiber with random birefringence and has the advantage of being polarization independent of both data and control signal, thus constituting a polarization independent AND-gate. Finally a scheme utilizing the optical Kerr effect in a polarization diversity loop is demonstrated. This scheme is not an interferometer which results in better stability than other NOLMs. In addition, a solution to make the NOLM insensitive to acoustical disturbances by rewinding the loop fiber is demonstrated