Book Reviews

Book Review 1Book Title: Reproductive Energetics in MammalsBook Authors: A.S.I. Loudon & P.A. Racey (Eds.)Zoological Society of London Symposia 57, 1987 Clarendon. Press, Oxford. 371 pp.Book Review 2Book Title: Classification of Southern African MammalsBook Authors: J.A.J. Meester, I.L. Rautenbach, N.J. Dippenaar & C.M. BakerTransvaal Museum Monograph No.5. 359 pp.Book Review 3Book Title: Pesticide impact on stream fauna with special reference to macroinvertebratesBook Author: R.C. Muirhead-ThomsonCambridge University Press, 1987. 275 pp.Book Review 4Book Title: Evolution of sex determining mechanismsBook Author: James J. BullBenjamin-Cummings Publ. Company / Addison-Wesley Publishing Group, JohannesburgBook Review 5Book Title: The evolutionary ecology of ant-plant mutualismsBook Author: Andrew J. BeattieCambridge University Press 182 pp.Book Review 6Book Title: The Ecology of SexBook Authors: P.J. Greenwood & J. Adams Edward Arnold, London, 1987. 74 pagesBook Review 7Book Title: The Dinosaur Heresies - a revolutionary view of dinosaursBook Author: Robert BakkerPublished by Longman Scientific and Technical, 1987Book Review 8Book Title: Molecular Biology of the GeneBook Authors: Watson, Hopkins, Roberts, Steitz & WeinerVolumes I and II (Fourth Edition) (Benjamin/Cummings. Menlo Park); Addison-Wesley Publishing Group. Johannesburg 1163 pp.Book Review 9Book Title: Evolutionary BiologyBook Author: Eli C. MinkoffAddison-Wesley Publishing Company, Massachussets, 1983. 627pp.Book Review 10Book Title: An ecosystem approach to aquatic ecology. Mirror Lake and its environmentBook Author: Gene E. Likens (Ed.)Springer-Ver1ag, New York. xiv - 516 pages; 197 figuresBook Review 11Book Title: The Physiological Ecology of SeaweedsBook Authors: C.S. Lobban, P.J. Harrison & M.J. Duncan Cambridge University press, Cambridge, 1985. 242 pagesBook Review 12Book Title: Principles of ecologyBook Authors: R.J.Putman & S.D. WrattenCroom Helm, London, 1984. 388 pages

Effects of p-type-metal-doping (Ba, Cs, and Y) of the compact-TiO2 electron transporting layer on the photovoltaic properties of n-i-p perovskite solar cells

Tailoring of charge transport properties of the electron transport layer (ETL) in solution-processible solar cells is continuously addressed not only for the performance enhancements in perovskite solar cells but also in various other applications in nanotechnology. In this work, three p-type dopants: barium, cesium (Cs), and yttrium (Y) with varying crystal radii and charges are doped in the titanium dioxide (TiO2) material so as to modify the electrical and optical properties of the ETL. The pure and doped TiO2 films were prepared by spin-coating a sol–gel precursor and their effects on the crystal structure, morphology, optical, electrical and photovoltaic properties of the perovskite solar cells were studied and reported. Among them, Y-doped TiO2 with similar crystal radii as that of the host titanium atom showed an enhanced photo-conversion efficiency mainly contributed by enhanced open circuit voltage and fill factor. The power conversion efficiency (PCE) for the perovskite absorber layer on Cs- and Y-doped TiO2 show the maximum PCE of 2.81 and 4.50% respectively. These are encouraging results for optimizing the yttrium doping level and fabrication conditions to further push the performance indicators of PSCs

Gravitational Lensing by Black Holes

We review the theoretical aspects of gravitational lensing by black holes, and discuss the perspectives for realistic observations. We will first treat lensing by spherically symmetric black holes, in which the formation of infinite sequences of higher order images emerges in the clearest way. We will then consider the effects of the spin of the black hole, with the formation of giant higher order caustics and multiple images. Finally, we will consider the perspectives for observations of black hole lensing, from the detection of secondary images of stellar sources and spots on the accretion disk to the interpretation of iron K-lines and direct imaging of the shadow of the black hole.Comment: Invited article for the GRG special issue on lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). 31 pages, 12 figure

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

The spins of ten stellar black holes have been measured using the continuum-fitting method. These black holes are located in two distinct classes of X-ray binary systems, one that is persistently X-ray bright and another that is transient. Both the persistent and transient black holes remain for long periods in a state where their spectra are dominated by a thermal accretion disk component. The spin of a black hole of known mass and distance can be measured by fitting this thermal continuum spectrum to the thin-disk model of Novikov and Thorne; the key fit parameter is the radius of the inner edge of the black hole's accretion disk. Strong observational and theoretical evidence links the inner-disk radius to the radius of the innermost stable circular orbit, which is trivially related to the dimensionless spin parameter a_* of the black hole (|a_*| < 1). The ten spins that have so far been measured by this continuum-fitting method range widely from a_* \approx 0 to a_* > 0.95. The robustness of the method is demonstrated by the dozens or hundreds of independent and consistent measurements of spin that have been obtained for several black holes, and through careful consideration of many sources of systematic error. Among the results discussed is a dichotomy between the transient and persistent black holes; the latter have higher spins and larger masses. Also discussed is recently discovered evidence in the transient sources for a correlation between the power of ballistic jets and black hole spin.Comment: 30 pages. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher). Changes to Sections 5.2, 6.1 and 7.4. Section 7.4 responds to Russell et al. 2013 (MNRAS, 431, 405) who find no evidence for a correlation between the power of ballistic jets and black hole spi

The global retinoblastoma outcome study : a prospective, cluster-based analysis of 4064 patients from 149 countries

DATA SHARING : The study data will become available online once all analyses are complete.BACKGROUND : Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival. METHODS : We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1, 2017, and Dec 31, 2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models. FINDINGS : The cohort included 4064 children from 149 countries. The median age at diagnosis was 23·2 months (IQR 11·0–36·5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0·8%) of 636 children from high-income countries, 55 (5·4%) of 1027 children from upper-middle-income countries, 342 (19·7%) of 1738 children from lower-middle-income countries, and 196 (42·9%) of 457 children from low-income countries. Enucleation surgery was available for all children and intravenous chemotherapy was available for 4014 (98·8%) of 4064 children. The 3-year survival rate was 99·5% (95% CI 98·8–100·0) for children from high-income countries, 91·2% (89·5–93·0) for children from upper-middle-income countries, 80·3% (78·3–82·3) for children from lower-middle-income countries, and 57·3% (52·1-63·0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16·67; 95% CI 4·76–50·00), cT4 advanced tumour compared to cT1 (8·98; 4·44–18·18), and older age at diagnosis in children up to 3 years (1·38 per year; 1·23–1·56). For children aged 3–7 years, the mortality risk decreased slightly (p=0·0104 for the change in slope). INTERPRETATION : This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes.The Queen Elizabeth Diamond Jubilee Trust and the Wellcome Trust.https://www.thelancet.com/journals/langlo/homeam2023Paediatrics and Child Healt

Electronic thermal conductivity, thermoelectric properties and supercapacitive behaviour of conjugated polymer nanocomposite (polyaniline-WO

A facile two-step, binder-free, chemical bath deposition (CBD) method was successfully employed in the synthesis of WO3 nanograins onto the matrix of conjugated polymer (polyaniline). The X-ray diffraction (XRD) results showed that the nanocomposite retained monoclinic phase of WO3 even when dispersed in polyaniline matrix. Owing to the synergistic effect offered by both the nanocomposite and structured metal oxide which may enhance the surface area, polyaniline-WO3 nanocomposite exhibited good specific capacitance. Polyaniline-WO3 yielded maximum specific capacitance ~96 F/g at scan rate of 5 mV/s in 0.5 M H2SO4 electrolyte. With the electronic thermal conductivity showing strong dependence on temperature, the estimated dimensionless figure of merit zT ~ 10−3 shows that the polymer nanocomposite (PNC) is promising as a new type of thermoelectric material. The electrochemical impedance spectroscopy showed that the PNC exhibited both pseudocapacitive and electric double layer capacitance behaviour

Dietary patterns of five-year-old children and their correlates: findings from a multi-ethnic Asian cohort

There is limited data on the dietary patterns of 5-year-old children in Asia. The study examined childhood dietary patterns and their maternal and child correlates in a multi-ethnic Asian cohort. Based on caregiver-reported one-month quantitative food frequency questionnaires of 777 children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort, cluster analysis identified two mutually exclusive clusters. Children in the “Unhealthy” cluster (43.9%) consumed more fries, processed meat, biscuits and ice cream, and less fish, fruits and vegetables compared to those in the “Healthy” cluster (56.1%). Children with mothers of lower educational attainment had twice the odds of being assigned to the “Unhealthy” cluster (adjusted OR (95% CI) = 2.19 (1.49-3.24)). Children of Malay and Indian ethnicities had higher odds of being assigned to the “Unhealthy” cluster (adjusted OR = 25.46 (15.40-42.10) and 4.03 (2.68-6.06)) respectively, relative to Chinese ethnicity. In conclusion, this study identified two dietary patterns in children, labelled as the “Unhealthy” and “Healthy” clusters. Mothers’ educational attainment and ethnicity were two correlates that were associated with the children’s assignments to the clusters. These findings can assist in informing health promotion programmes targeted at Asian children