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Transcriptomic response of maize primary roots to low temperatures at seedling emergence
No full textBackground. Maize (Zea mays) is a C4 tropical cereal and its adaptation to temperate
climates can be problematic due to low soil temperatures at early stages of establishment.
Methods. In the current study we have firstly investigated the physiological response
of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal
growth temperature during seedling emergence. To identify transcriptomic markers
of cold tolerance in already adapted maize genotypes, temperature conditions were
set below the optimal growth range in both control and low temperature groups.
The conditions were as follows; control (18 ◦C for 16 h and 12 ◦C for 8 h) and low
temperature (12 ◦C for 16 h and 6 ◦C for 8 h). Four genotypes were identified from the
condition adapted gene pool with significant contrasting chilling tolerance.
Results. Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco
were the less cold-tolerant lines. These four varieties were subjected to microarray
analysis to identify differentially expressed genes under chilling conditions. Exposure
to low temperature during establishment in the maize varieties Picker, PR39B29,
Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and
PR39B29. No significant changes in expression were observed in Fergus and Codisco
following chilling stress. A total number of 64 genes were differentially expressed in the
two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic
profiles, in which only four genes overlapped.
Discussion. We observed that maize varieties possessing an enhanced root growth ratio
under low temperature were more tolerant, which could be an early and inexpensive
measure for germplasm screening under controlled conditions. We have identified
novel cold inducible genes in an already adapted maize breeding gene pool. This
illustrates that further varietal selection for enhanced chilling tolerance is possible in
an already preselected gene pool
Transmission expansion planning in presence of electric vehicles at the distribution level
No full textThe planning of the transmission network is an issue that, over the years, has received much attention, particularly due to the impact that this infrastructure has on the safe and reliable functioning of electrical systems. The search for solutions addressing climate change has led to several changes in the functioning of electrical systems, particularly concerning the increasing integration of renewable electricity production. However, in recent years, changes in the load side of the electrical system have also emerged. In particular, electric mobility has been developing, and a high penetration of electric vehicles (EVs) is expected in near future. This consumption is supplied by the distribution system but will impact the transmission network. Naturally, the amount of energy used by EVs is subject to uncertainties, which makes the problem complex. Those uncertainties cannot be easily modeled using statistical distributions because of the reduced history of available information. The transmission system operator (TSO) needs an efficient tool to analyze the adequacy of the transmission network to supply the distribution networks with high penetration of EVs. In this paper, a methodology based on symmetric/constrained fuzzy power flow is proposed to find the optimal investment policy at the transmission level while satisfying the technical constraints. The concept of dual variables provided by Lagrange multipliers, the natural result of the nonlinear optimization problem, is used to obtain the most promising reinforcement options considering the actual structure of the transmission network. The proposed model is tested on an IEEE 14-bus system
1.3 μm wavelength tunable single-mode laser arrays based on slots
No full textTwo twelve-channel arrays based on surface-etched slot gratings, one with non-uniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater than 40 nm, with a side-mode suppression ratio (SMSR) > 40 dB over much of this range and output power greater than 20 mW, was obtained for the array with non-uniform slots over a temperature range of 15 °C - 60 °C. The introduction of multiple slot periods, chosen such that there is minimal overlap among the side reflection peaks, is employed to suppress modes lasing one free spectral range (FSR) from the intended wavelength. The tuning range of the array with uniformly spaced slots, on the other hand, was found to be discontinuous due to mode-hopping to modes one FSR away from the intended lasing mode which are not adequately suppressed. Spectral linewidth was found to vary across devices with the lowest measured linewidths in the range of 2 MHz to 4 MHz
Design and Analysis of the Optical Beam Combiner and Corrugated Feed Horns for the QUBIC Instrument
No full textThe next major step in Big Bang cosmology will be the detection of primordial B-modes in the polarisation pattern of the Cosmic Microwave Background (CMB). These primordial B-modes are extremely faint and unprecedented levels of sensitivity will be required to detect them. The QUBIC (Q & U Bolometric Interferometer for Cosmology) instrument, first proposed in 2008 and now on the verge of being commissioned, aims to detect them by using the novel technique of bolometric interferometry to combine the control of systematics provided by an interferometer and the sensitivity provided by an imager. QUBIC is a ground-based instrument that will be installed in Salta Province, Argentina.
This thesis describes the detailed optical analysis of the QUBIC instrument and, in particular, its quasi-optical beam combiner. Two variations of QUBIC are analysed: the full instrument (FI) and a technological demonstrator (TD). It was decided to develop the smaller optical combiner of the TD in 2015. The justification for and analysis of the TD are also presented.
The QUBIC FI will observe over two bands: 150 GHz (with a 25% bandwidth) and 220 GHz (with an 18% bandwidth). The operation of the QUBIC optical combiner across these bands was investigated using the techniques of physical optics and electromagnetic mode-matching for the feedhorns. This modelling also provided an insight into multimoded operation of QUBIC in the higher band, which will be useful for future instruments that aim to exploit the phenomenon.
The optical modelling in this thesis has been used in the calibration and testing phases of the instrument and will be also useful in the future when observations begin in Argentina
Measurement and prevalence of adult physical activity levels in Arab countries
No full textObjectives: This study aims to examine the reported prevalence of sufficient physical activity among adults in Arab countries and to determine the use of validated instruments for assessing physical activity. Study design: This is a systematic literature review. Methods: This review follows recommendations outlined in the Meta-Analysis of Observational Studies in Epidemiology guidelines. The protocol for this study was preregistered with PROSPERO. Cross-sectional, cohort and intervention studies with a minimum of 300 adults aged 18 years assessing physical activity using a questionnaire or other self-report measure in the Arabic language were identified from seven electronic databases (MEDLINE, Embase, Cochrane Database of Systematic Reviews, CINAHL, PsycINFO, SPORTDiscu and PubMed). Databases were searched from 1st January 2008 to 17th September 2018. Descriptive analysis was performed using frequency and percentages. The prevalence of physical activity was calculated as the average prevalence for the reported percentages from the studies with similar tools. Results: Fifty studies involving 298,242 participants were included in this review. The mean (range) sample size was 5964.8.1 (323e197,681). Data were collected from participants in 16 of the 22 Arab countries. Great variation exists across the studies in determining whether adults were sufficiently active or not. Twenty studies reported usable data from the Global Physical Activity Questionnaire and the International Physical Activity Questionnaire (moderate & high categories). In these studies, prevalence of physical activity ranged from 34.2 to 96.9%. It was not possible to compare the other studies owing to variation in instruments used to assess physical activity and in the case definition used for ‘physically
active’. Conclusions: This study highlights the need for wider reporting of physical activity and the adoption of valid and reliable instruments to support the development of evidence-informed policy and programmes at both country and regional level. International tools need to be correctly validated, or context-specific tools must be developed to accurately measure physical activit
Dancing on the Threshold of Time: An Orphic Journey into the Second Half of Life.
No full textMy thesis is concerned with storying the lived experience of being on the threshold
between the first and the second half of life, using the archetypal mythical framework of
Orpheus and Eurydice, a story of love, loss and transformation. This work produces an
alternative knowledge about this stage of adult development, in attending to the process
of loss, mourning and letting go. Drawing on the conceptual framework of
poststructuralism and social constructionism, the thesis is developed by troubling the
legitimacy of our social and cultural constructions, disrupting their power through our
storytelling, making visible how we make meaning and create knowledge. It offers an
alternative viewpoint to the predominant psychological narrative of “the first person
perspective” (Zahavi, 2008:107), to being storied and understood in our social and
cultural contexts, “as a product of narratively structured life” (Zahavi, 2008:107),
“rather than separated pieces related only to [our] personal psychology” (Etherington,
2009: 228).The autoethnographic expression of this stage of adult development is re-imagined in this thesis, in being situated in the betwixt and between reveried space of
the upper and the lower worlds, the living and the dead, the conscious and the
unconscious. It is here, in this narrative space, we bear witness to, and avow each
other’s unfinished stories of love and loss, opening up a “narrative of reconciliation”
(Ahmed, 2014: 35), freeing us like Orpheus and Eurydice, into our own destinies. In the
movement of these six Orphic Moments, there is a rhythm often visible and invisible
that traces the bitter-sweetness of being on the threshold of time, between the first and
the second half of life. Each Moment signifies an invitation to accept the
Orphic/Eurydician call to “stand in the heat of this transformation fire” (Hollis, 2006,
31), and become deeply immersed in mourning to that place of transformation, with the
living and the dead. This study produces a new methodological knowledge of this phase
of adult development, through a process of engaging relationally and reciprocally with
each other, in becoming witnesses to each other’s stories, enabling “a transformation of
the self, from which there is no return” (Butler, 2005: 28). This thesis gestures to an
alternative view on how we can re-imagine more expansive ways of living for the
second half of life, where “voice is always provisional and contingent, always
becoming” (Grant, 2013: 8), where we can “produce a different knowledge and produce
knowledge differently” (St. Pierre, 1997: 613)
Spring and autumn movements of an Arctic bird in relation to temperature and primary production
No full textIt is increasingly important to understand animal migratory movements because climate disruption is shifting plant and animal phenology at different rates across the world. We applied a Markov state-switching model to telemetry data of a long-distance migrant, the barnacle goose, to detect migratory movement and relate it to three proximate environmental factors: photoperiod, daily mean temperature and forage plant phenology. Spring migratory movements towards the breeding grounds were most closely related to forage plant phenology (measured by accumulated growing degree days, GDDs); high GDDs values were associated with a greater probability of transiting to a more northerly site, suggesting that spring migration is closely aligned with primary productivity. Autumn migration from the breeding grounds was most closely related to temperature; higher temperature values were associated with a greater probability of remaining settled at the current site, suggesting that autumn migration is closely aligned with atmospheric conditions. Understanding the relative influence of different environmental factors on migratory patterns may in turn provide us with insight into how continued climate disruption could influence northern migratory systems
Quality prediction of ultrasonically welded joints using a hybrid machine learning model
No full textUltrasonic metal welding has advantages over other joining technologies due to its low energy consumption, rapid cycle time and the ease of process automation. The ultrasonic welding (USW) process is very sensitive to process parameters, and thus can be difficult to consistently produce strong joints. There is significant interest from the manufacturing community to understand these variable interactions. Machine learning is one such
method which can be exploited to better understand the complex interactions of USW input parameters. In this paper, the lap shear strength (LSS) of USW Al 5754 joints is investigated using an off-the-shelf Branson Ultraweld L20. Firstly, a 33 full factorial parametric study using ANOVA is carried out to examine the effects of three USW
input parameters (weld energy, vibration amplitude & clamping pressure) on LSS. Following this, a high-fidelity predictive hybrid GA-ANN model is then trained using the input parameters and the addition of process data recorded during welding (peak power). Once trained, the predictive model is tested against seven unseen parameter combinations specimens. Analysing the experimental data shows that the LSS performance envelop is non-linear with respect to the process variables of clamping pressure, vibration amplitude and welding energy. Vibration amplitude is the dominant input parameter affecting the LSS of the joints. At a fixed welding energy, the LSS can be increased by increasing vibration amplitude. However, the effect of clamping pressure on LSS is dependent on the level of welding energy. The resultant GA-ANN model accurately predicts the LSS of unseen test data producing a mean absolute percentage error of 7.51% with a Pearson\u27s correlation coefficient of 0.96 for all data. It is demonstrated that including process data in a closed loop reduces the mean prediction error from 13.17% to 7.5
"The Best Country in the World": The Surprising Social Mobility of New York’s Irish Famine Immigrants
No full textWe use databases we have created from the records of New York’s Emigrant Savings Bank, founded by pre-Famine Irish immigrants and their children to serve Famine era immigrants, to study the social mobility of bank customers and, by extension, Irish immigrants more generally. We infer that New York’s Famine Irish had a greater range of employment opportunities open to them than perhaps commonly acknowledged, and that the majority were eventually able to move a rung or two up the American socio-economic ladder, supporting the conviction of many Famine immigrants that the U.S. was indeed “the best country in the world.
Persistence, Randomization, and Spatial Noise
No full textHistorical persistence studies and other regressions using spatial data commonly have severely inflated t statistics, and different standard error adjustments to correct for this return markedly different estimates. This paper proposes a simple randomization inference procedure where the significance level of an explanatory variable is measured by its ability to outperform synthetic noise with the same estimated spatial structure. Spatial noise, in other words, acts as a treatment randomization in an artificial experiment based on correlated observational data. Combined with Müller and Watson (2021), randomization gives a way to estimate credible confidence intervals for spatial regressions. The performance of twenty persistence studies relative to spatial noise is examined