The development of the early Safawid state under Isma'il and Tahmasp, as studied in the 16th century Persian sources.

The object of this thesis is, from a study of the contemporary Persian sources, to determine the broad outlines of the development of the early Safawid state, and in particular to describe the evolution of the principal offices of state. As the reforms of 'Abbais I (1587-1629) had a profound effect on the structure and organization of the Safawid state, the accession of 'Abbas I forms a convenient point at which to terminate this thesis, which therefore relates in the main to the reigns of Isma'il I (1501/2-1524) and Tahmasp I (1524-76). An attempt has been made to show how the fundamental dichotomy between Turk and Persian, the lack of any precise definition of the functions of the chief dignitaries, and the absence of any clear differentiation between the classes, affected the development of the Safawid state during this period. It should be noted that this thesis deals only with the most important offices of state, and does not purport to be in any way a complete description of the early Safawid administrative system. An attempt has also been made to determine the factors which enabled the Safawids to impose Shi'ism as the orthodox religion of the Safawid state. In writing the historical background to this thesis, I have endeavoured, on the one hand, to give the shortest account of events consonant with a proper understanding of the period, and, on the other hand, to give a rather fuller picture of events in Khurasan, 'Iraq-i 'Ajam and Fars, during the hundred years between the death of Timur and the accession of Isma'il, than is to be found elsewhere

Frenkel Excitons in Vacancy-Ordered Titanium Halide Perovskites (Cs₂TiX₆)

[Image: see text] Low-cost, nontoxic, and earth-abundant photovoltaic materials are long-sought targets in the solar cell research community. Perovskite-inspired materials have emerged as promising candidates for this goal, with researchers employing materials design strategies including structural, dimensional, and compositional transformations to avoid the use of rare and toxic elemental constituents, while attempting to maintain high optoelectronic performance. These strategies have recently been invoked to propose Ti-based vacancy-ordered halide perovskites (A(2)TiX(6); A = CH(3)NH(3), Cs, Rb, or K; X = I, Br, or Cl) for photovoltaic operation, following the initial promise of Cs(2)SnX(6) compounds. Theoretical investigations of these materials, however, consistently overestimate their band gaps, a fundamental property for photovoltaic applications. Here, we reveal strong excitonic effects as the origin of this discrepancy between theory and experiment, a consequence of both low structural dimensionality and band localization. These findings have vital implications for the optoelectronic application of these compounds while also highlighting the importance of frontier-orbital character for chemical substitution in materials design strategies

Frenkel Excitons in Vacancy-Ordered Titanium Halide Perovskites (Cs₂TiX₆)

Low-cost, nontoxic, and earth-abundant photovoltaic materials are long-sought targets in the solar cell research community. Perovskite-inspired materials have emerged as promising candidates for this goal, with researchers employing materials design strategies including structural, dimensional, and compositional transformations to avoid the use of rare and toxic elemental constituents, while attempting to maintain high optoelectronic performance. These strategies have recently been invoked to propose Ti-based vacancy-ordered halide perovskites (A2TiX6; A = CH3NH3, Cs, Rb, or K; X = I, Br, or Cl) for photovoltaic operation, following the initial promise of Cs2SnX6 compounds. Theoretical investigations of these materials, however, consistently overestimate their band gaps, a fundamental property for photovoltaic applications. Here, we reveal strong excitonic effects as the origin of this discrepancy between theory and experiment, a consequence of both low structural dimensionality and band localization. These findings have vital implications for the optoelectronic application of these compounds while also highlighting the importance of frontier-orbital character for chemical substitution in materials design strategies

Experimental and First-Principles Spectroscopy of Cu₂SrSnS₄ and Cu₂BaSnS₄ Photoabsorbers

Cu2BaSnS4 (CBTS) and Cu2SrSnS4 (CSTS) semiconductors have been recently proposed as potential wide band gap photovoltaic absorbers. Although several measurements indicate that they are less affected by band tailing than their parent compound Cu2ZnSnS4, their photovoltaic efficiencies are still low. To identify possible issues, we characterize CBTS and CSTS in parallel by a variety of spectroscopic methods complemented by first-principles calculations. Two main problems are identified in both materials. The first is the existence of deep defect transitions in low-temperature photoluminescence, pointing to a high density of bulk recombination centers. The second is their low electron affinity, which emphasizes the need for an alternative heterojunction partner and electron contact. We also find a tendency for downward band bending at the surface of both materials. In CBTS, this effect is sufficiently large to cause carrier-type inversion, which may enhance carrier separation and mitigate interface recombination. Optical absorption at room temperature is exciton-enhanced in both CBTS and CSTS. Deconvolution of excitonic effects yields band gaps that are about 100 meV higher than previous estimates based on Tauc plots. Although the two investigated materials are remarkably similar in an idealized, defect-free picture, the present work points to CBTS as a more promising absorber than CSTS for tandem photovoltaics

Prevalence and predictors of poor mental health among pregnant women in Wales using a cross-sectional survey

Objectives To assess the prevalence of self-reported mental health problems in a cohort of women in early pregnancy. To describe the relationship between poor mental health and sociodemographic characteristics, self-efficacy and support networks. To assess if participants were representative of the local antenatal population. Research design and setting The UK government has pledged money to provide more support for women with perinatal mental health issues. Understanding the prevalence and predicting women who may need support will inform clinical practice. This paper reports part of the larger ‘Mothers Mood Study’, which explored women's and midwives’ experience of mild to moderate perinatal mental health issues and service provision. Routinely collected population level data were analysed and a smaller cross-sectional survey design used to assess predictors of poor mental health in early pregnancy in one health board in Wales. Participants Routinely collected data were extracted for all women who registered for maternity care between May 2017 and May 2018 (n = 6312) from the electronic maternity information system (pregnant population). Over a three month period 302 of these women completed a questionnaire at the antenatal clinic after an ultrasound scan (participants). Eligible women were aged ≥18 years, with sufficient spoken and written English to complete the questionnaire and a viable pregnancy of ≤18 weeks’ gestation. The questionnaire collected data on sociodemographic status, self-efficacy and support networks, self-reported mental health problems. Current anxiety and depression were assessed using the General Anxiety Disorders Assessment and Edinburgh Postnatal Depression Scale. Findings Among the pregnant population 23% (n = 1490) disclosed a mental health problem during routine questioning with anxiety and depression being the most common conditions. Participants completing the detailed questionnaire were similar in age and parity to the pregnant population with similar levels of depression (15.6%; n = 15.6 v 17.3%, n = 1092). Edinburgh Postnatal Depression Scale and General Anxiety Disorder 7 scores identified 8% with symptoms of anxiety (n = 25) or depression (n = 26) and a further 24.2% (n = 73) with symptoms of mild anxiety and 25.2% (n = 76) with mild depression. Low self-efficacy (OR 1.27, 95% CI 1.12–1.45), a previous mental health problem (OR 3.95, 95% CI 1.37–11.33) and low support from family (OR 1.13, 95% CI 1.00–1.27) were found to be associated with early pregnancy anxiety and/or depression. Key conclusions and implications for practice Around one in five women who register for maternity care may have a mental health problem. Mild to moderate anxiety and depression are common in early pregnancy. Services need to improve for women who do not currently meet the threshold for referral to perinatal mental health services. Assessment and active monitoring of mental health is recommended, in particular for pregnant women with risk factors including a history of previous mental health difficulties, poor family support or low self-efficacy

Unrepeatered Transmission Over 253.4 km Ultra Low Loss Fibre Achieving 6.95 (b/s)/Hz Se Using EDFA-Only Pre-Amplifier

A 560 Gb/s (7×80 Gb/s Nyquist spaced PDM-16QAM) superchannel achieving 6.95 b/s/Hz spectral efficiency is transmitted over 253.4 km SMF-28® ULL fiber using only EDFA pre-amplification and full-field nonlinear back-propagation, corresponding to a record SE-distance product of 1761.1 b/s/Hz·km

Seasonal variation in salivary cortisol but not symptoms of depression and trait anxiety in pregnant women undergoing an elective caesarean section

Objectives Seasonal changes in mood and behaviour are commonly reported in the general population but considerably less is known regarding seasonality and pregnancy. This study investigated the relationship between seasons and depression and anxiety symptoms, salivary cortisol concentrations, custom birthweight centiles (CBWC) and placenta weight for pregnant women living in South Wales. Methods This study utilised data from the longitudinal Grown in Wales (GiW) cohort. Women were recruited at the presurgical elective caesarean section (ELCS) appointment, when they provided saliva samples and completed the Edinburgh Postnatal Depression Scale (EPDS) and trait subscale of the State-Trait Anxiety Inventory (STAI). Data on birthweight and placental weight was extracted from medical notes. Seasonal data was available for 316 participants. Results No association was identified between seasons and EPDS (p = .178), STAI scores (p = .544), CBWC (p = .683) or placental weight (p = .857). Significance was identified between seasons and salivary cortisol concentration (p<.001), with highest levels in autumn and winter. Adjusted linear regression identified spring (B=−.05, p=.007, 95% CI −.09, −.01) and summer (B=−.06, p = .001, 95% CI −09, −.02) compared to autumn, and spring (B=−.05, p=.009, 95% CI −.09, −.01) and summer (B=−.06, p=.002, 95% CI −.10, −.02) compared to winter to be associated with decreased cortisol concentrations. Conclusion This study found no association between season and maternally-reported mental health symptoms, birthweight by CBWC or placental weight but did between season and term salivary cortisol. This finding will have implications for studies that do not account for seasonality when using salivary cortisol as a biomarker