Breeding for improved nitrogen use efficiency in oilseed rape

Oilseed rape has a high requirement for nitrogen (N) fertiliser relative to its seed yield. This paper uses published and unpublished work to explore the extent to which the N use efficiency (seed yield ÷ N supply) of oilseed rape could be improved without reducing seed yield. It was estimated that if the concentration of N in the stem and pod wall at crop maturity could be reduced from 1.0 to 0.6%, the root length density increased to 1 cm/cm3 to 100 cm soil depth and the post flowering N uptake increased by 20 kg N/ha then the fertiliser requirement could be reduced from 191 to 142 kg N/ha and the N use efficiency could be increased from 15.2 to 22.4 kg of seed dry matter per kg N. Genetic variation was found for all of the traits that were estimated to be important for N use efficiency. This indicates that there is significant scope for plant breeders to reduce N use efficiency in oilseed rape

Absorbance Modulation Optical Lithography: Simulating the Performance of an Adaptable Absorbance Mask in the Near-Field.

The challenge for lithography today is to continue the reduction of feature size whilst facing severe theoretical and practical limitations. In 2006 Rajesh Menon and Hank Smith proposed a new lithography system named absorbance modulation optical lithography (AMOL) [Menon 2006]. AMOL proposed replacing the normal metal mask of a lithography system with an absorbance modulation layer (AML), made from a photochromic material. This allows, through the competition between two incident wavelengths, the creation of an adaptive absorbance mask. The AML allows intimate contact to an underlying resist and hence the optical near-field may be used to create sub-diffraction limited exposures. The aim of this thesis is to model AMOL and demonstrate the abilities and the limits of the system, particularly focusing on sub-diffraction limited imaging. This thesis describes the construction of a vector electromagnetic simulation to explore the idea and performance of AMOL, and an exploration of the ability of AMOL to propagate sub-diffraction limited images into a photoresist. A finite element method (FEM) model was constructed to simulate the formation of apertures in the AML and light transmission through the system. Three major areas of interest were explored in this thesis; the effect of polarisation on imaging, using a plasmonic reflector layers (PRLs) to improve the depth of focus (DOF), and introducing a superlens to AMOL. Investigations of polarisation demonstrated strong preference for a transverse magnetic (TM) polarised exposing wavelength for near-field exposures. Associated with polarisation, and supporting work with absorbance gratings, the importance of the material parameters of the AML in allowing sub-diffraction limited exposures was discussed. It was also noted that, in common with all near-field systems, the depth of focus (DOF) was poor, worse than comparable metal systems. This thesis also demonstrates that the introduction of a PRL can improve the DOF and process latitude for resist thicknesses up to 60 nm and, although performance was reduced when using a silver PRL, the substantial improvements to the DOF and process latitude make a PRL valuable for an AMOL system. This thesis also models the superlens to an AMOL system, which theoretically allows propagation of the image in the near-field. It is demonstrated that the superlens can project an AMOL image into an underlying resist, but that this image is degraded, especially for thick and non-ideal superlenses. The superlens does have a second useful effect, as it can act as a dichroic filter; decreasing the intensity ratio in the resist by a factor of ten, overcoming issues of resist sensitivity. The superlens can allow image projection and filtering with AMOL, however improvements to the available superlens materials or changes to the AML will be needed to avoid image deterioration. This thesis has developed the first full-vector model of an absorbance modulation optical lithography (AMOL) system. This model has been used to increase the understanding of the complex effects that go into the creation of sub-diffraction limited features with AMOL. In particular the model has been used to investigate polarisation, PRLs and superlenses in AMOL. This thesis demonstrates the ability of AMOL to create narrow apertures and sub-diffraction limited exposures in a photoresist, and describes the limitations of AMOL, including material parameters and DOF. AMOL is a new and interesting lithography technique; this thesis simulates the abilities and challenges of sub-diffraction lithography using an AMOL system

Racial and Ethnic Disparities in Health in Latin America and the Caribbean

There is increasing awareness that race and ethnicity play an important role in the poverty and social marginalization of Latin American and Caribbean populations.Health Care

eIF4A inhibitors suppress cell-cycle feedback response and acquired resistance to CDK4/6 inhibition in cancer

CDK4/6 inhibitors are FDA-approved drugs for estrogen receptor-positive (ER+) breast cancer and are being evaluated to treat other tumor types, including KRAS-mutant non-small cell lung cancer (NSCLC). However, their clinical utility is often limited by drug resistance. Here, we sought to better understand the resistant mechanisms and help devise potential strategies to overcome this challenge. We show that treatment with CDK4/6 inhibitors in both ER+ breast cancer and KRAS-mutant NSCLC cells induces feedback upregulation of cyclin D1, CDK4, and cyclin E1, mediating drug resistance. We demonstrate that rocaglates, which preferentially target translation of key cell-cycle regulators, effectively suppress this feedback upregulation induced by CDK4/6 inhibition. Consequently, combination treatment of CDK4/6 inhibitor palbociclib with the eukaryotic initiation factor (eIF) 4A inhibitor, CR-1-31-B, is synergistic in suppressing the growth of these cancer cells in vitro and in vivo Furthermore, ER+ breast cancer and KRAS-mutant NSCLC cells that acquired resistance to palbociclib after chronic drug exposure are also highly sensitive to this combination treatment strategy. Our findings reveal a novel strategy using eIF4A inhibitors to suppress cell-cycle feedback response and to overcome resistance to CDK4/6 inhibition in cancer.Accepted manuscrip

The individual and the system : Assessing the stability of the output of a semi-automatic forensic voice comparison system

Semi-automatic systems based on traditional linguistic-phonetic features are increasingly being used for forensic voice comparison (FVC) casework. In this paper, we examine the stability of the output of a semi-automatic system, based on the long-term formant distributions (LTFDs) of F1, F2, and F3, as the channel quality of the input recordings decreases. Cross-validated, calibrated GMM-UBM log likelihood-ratios (LLRs) were computed for 97 Standard Southern British English speakers under four conditions. In each condition the same speech material was used, but the technical properties of the recordings changed (high quality studio recording, landline telephone recording, high bit-rate GSM mobile telephone recording and low bit-rate GSM mobile telephone recording). Equal error rate (EER) and the log LR cost function (Cllr) were compared across conditions. System validity was found to decrease with poorer technical quality, with the largest differences in EER (21.66%) and Cllr (0.46) found between the studio and the low bit-rate GSM conditions. However, importantly, performance for individual speakers was affected differently by channel quality. Speakers that produced stronger evidence overall were found to be more variable. Mean F3 was also found to be a predictor of LLR variability, however no effects were found based on speakers’ voice quality profiles

Optimizing dry-matter partitioning for increased spike growth, grain number and harvest index in spring wheat

Improving biomass is an important goal for future genetic gains in yield potential in wheat, but it will also be crucial to identify physiological traits to maximize harvest index (HI, proportion of aboveground biomass in grain). Increased grain partitioning will require increased dry-matter (DM) partitioning to the spikes at anthesis as well as enhanced fruiting efficiency (FE, grains per g spike dry matter at anthesis or chaff dry matter at harvest), whilst optimizing the partitioning amongst the non-grain components to maintain post-anthesis photosynthetic capacity and soluble carbohydrate translocation. The objectives of this study were to: i) quantify genetic variation in DM partitioning among plant organs at anthesis (GS65) + 7days and associations with spike growth and FE and ii) identify optimized partitioning traits associated with enhanced HI and grain yield, in CIMMYT elite spring wheat backgrounds. Two field experiments were conducted in 2011-12 and 2012-13 testing 26 CIMMYT spring wheat cultivars in NW Mexico in irrigated conditions in which DM partitioning was assessed in plant organs at anthesis + 7 days, and within-spike (glume, palea, lemma, rachis and awn) partitioning was assessed at harvest. Grain yield, yield components, HI and FE were assessed at harvest. Our results identified new traits for HI (decreased DM partitioning to stem internodes 2 (top down, peduncle-1) and 3, and decreased rachis DM partitioning and rachis specific weight (rachis DM per rachis unit length) and increased lemma DM partitioning), potentially allowing breeders to maximize the exploitation of enhanced carbon assimilation for grain biomass. Further work will focus on understanding the role of soluble carbohydrate re-translocation in these relationships and establishing high-throughput and cost-effective phenotyping methods for these traits for deployment in breeding

The Physiological Basis of the Genetic Progress in Yield Potential of CIMMYT Spring Wheat Cultivars from 1966 to 2009

© Crop Science Society of America. Our objective was to investigate the physiological basis of genetic progress in grain yield in CIMMYT spring wheat (Triticum aestivum L.) cultivars developed from 1966 to 2009 in irrigated, high-potential conditions. Field experiments were conducted during three growing seasons in northwest Mexico (2008–2009, 2009–2010, and 2010–2011) examining 12 historic CIMMYT semidwarf spring wheat cultivars released from 1966 to 2009. The linear rate of genetic gain in grain yield was 30 kg ha−1 yr−1 (0.59% yr−1; R2 = 0.58, P = 0.01). Grain yield progress was associated with increased aboveground dry matter (AGDM) at harvest (R2 = 0.80, P < 0.001) and heavier grain weight (R2 = 0.46, P < 0.05). There was a positive linear association between AGDM and plant height (R2 = 0.43, P < 0.05) and between grain weight and the date of complete canopy senescence (CCS) among the 12 cultivars (R2 = 0.36, P < 0.05). There was no change in grains per square meter or harvest index (HI) with year of release (YoR). Grain weight was positively associated with potential grain weight (PGW), and PGW, in turn, was positively associated with rachis length per spikelet among the cultivars. Overall spike dry matter (DM) per square meter at anthesis (GS61) +7 d did not change with YoR. There was a trend for a linear increase in AGDM of fertile shoots (expressed as g m−2) at GS61 +7 d with YoR, but this was counteracted by spike partitioning decreasing overall during the 43-yr period from 0.25 to 0.23. There was a linear increase in preanthesis flag-leaf stomatal conductance with YoR (P < 0.05). There was no change in grain growth response to a degraining treatment imposed at GS61 +14 d (mean grain weight response +5.5%) indicating that the degree of source limitation to grain growth appeared to be small and unchanged in the older and modern cultivars. Generally, these results indicated that the rate of genetic progress in CIMMYT spring wheat has slowed but has not plateaued in recent decades, while genetic gains were associated with increase in both potential and final grain weight