Capacitive Micromachined Ultrasonic Transducer Array with Pencil Beam Shape and Wide Range Beam Steering

AbstractA capacitive micromachined ultrasonic transducer (CMUT) array is designed as an alternative to conventional piezoelectric transducers. A thin silicon nitride membrane is suspended over a bottom electrode on a silicon wafer. In the immersion mode, the transducer cell shape and dimensions are optimized for an operating frequency of 10MHz. We show that the proposed imager array can generate a pencil shape beam with a ∼1.5° half beam width, enhancing the detector resolution. A phased array technique is employed to excite multiple cells using time-delayed signals to steer the acoustic beam toward the object. This eliminates the need to mechanically move the detector, simplifying the transducer driving system. Moreover, unlike conventional transducers, the pencil beam can be effectively steered over a wide range of angles without producing grating lobes, which minimizes power loss in undesired directions. This can also improve the signal to noise ratio of the imager CMUT array

Unusual Regulatory Elements for Iron Deficiency Induction of the idiA Gene of Synechococcus elongatus PCC 7942

Expression of a thylakoid membrane-associated protein called IdiA (iron-deficiency-induced protein A) is highly elevated and tightly regulated by iron limitation in Synechococcus elongatus PCC 6301 and PCC 7942. Although this protein is not essential for photosystem II (PSII) activity, it plays an important role in protecting the acceptor side of PSII against oxidative damage, especially under iron-limiting growth conditions, by an unknown mechanism. We defined the iron-responsive idiA promoter by using insertional inactivation mutagenesis and reporter gene assays. A 67-bp DNA region was sufficient for full iron deficiency-inducible idiA promoter activity. Within this fragment is a palindromic sequence 4 bp upstream of a putative −35 promoter element, which resembles the binding site of FNR/CAP-type helix-turn-helix transcription factors. The absence of this palindromic sequence or a 3-bp mutation in a putative −10 region eliminated promoter activity completely. A previously identified candidate for a positively acting transcription factor is the IdiB protein, whose gene lies immediately downstream of idiA. IdiB shows strong similarity to helix-turn-helix transcription factors of the FNR/CAP family. A His(6x)-tagged IdiB that was overexpressed in Escherichia coli bound to a 59-bp fragment of the idiA regulatory region that included the palindrome. Although the idiA promoter lacks a consensus binding site for the iron-sensing regulator Fur, we attempted to inactivate fur in order to investigate the potential role of this factor. The resulting merodiploid mutants showed constitutive partial derepression of IdiA expression under iron-sufficient growth conditions. We concluded that IdiB is a specific iron-responsive regulator of idiA and that Fur has an indirect role in influencing idiA expression

Evidence for density dependent population regulation in southern elephant seals in the southern Indian Ocean

The means by which populations are regulated form a central theme in conservation biology, and much debate has revolved around density dependence as a mechanism driving population change. Marion Island (46o54'S, 37o45'E) is host to a relatively small breeding population of southern elephant seals, which like its counterparts in the southern Indian and southern Pacific Oceans, have declined precipitously over the past few decades. An intensive mark-recapture study, which commenced in 1983, has yielded a long time-series of resight data on this population. We used the program MARK to estimate adult female survival in this population from resight data collected over the period 1986-1999. Including concurrent population counts as covariates significantly improved our mark-recapture models and suggests density dependent population regulation to be operational in the population. Although predation may have been involved, it is far more likely that density dependent regulation has been based on a limited food supply. A significant increase in adult female survival was evident which is likely to have given rise to recent changes in population growth

The fetal profile line:a proposal for a sonographic reference line to classify forehead and mandible anomalies in the second and third trimester

Objectives To test the fetal profile (FP) line, defined as the line that passes through the anterior border of the mandible and the nasion, as a reference line for forehead and mandible anomalies. Methods Volumes of 248 normal and 24 pathological fetuses (1636 and 1937?weeks gestation, respectively) were analysed retrospectively. When the FP line passes anteriorly, across or posteriorly to the frontal bone, this was defined as negative, zero or positive, respectively. When the FP line was positive the distance (F distance) between the FP line and the frontal bone was measured. Results No cases with a negative FP line were found in the normal fetuses. Before 27?weeks gestation the FP line was always zero except in one case. After 27?weeks gestation the FP line was positive in up to 25% (F distance (mean, range): 2.8, 2.13.6?mm). The FP line correctly identified 13 cases with retrognathia, 5 cases with frontal bossing and 3 cases with a sloping forehead. Conclusion Although large prospective studies are needed, the FP line may be a useful tool to detect second trimester profile anomalies such as retrognathia, sloping forehead and frontal bossing with the possibility of quantifying the latter. (c) 2012 John Wiley & Sons, Ltd

Effectiveness of method improvements to reduce variability of brood termination rate in honey bee brood studies under semi-field conditions

Quantitative assessments of adverse effects of plant protection products on honey bee brood (Apis mellifera L.) may be carried out according to the methods given by the OECD Guidance Document No. 75 (2007). In recent years a number of studies displayed a strong variability in brood termination rates, a key endpoint. Due to these variances no definite conclusions regarding potential brood effects were possible, and the studies needed to be repeated. Due to this, attempts to improve the methodology were initiated by the Working Group ‘Honey bee brood' of the German AG Bienenschutz. In 2011, honey bee brood studies adapted to these identified possible improvements resulted in better results compared to historical data. Based on the analysed results, the working group recommends to improve the method by using bigger colonies with more brood, using 4 instead of 3 replicates for better interpretation of data, starting the study early in the season, avoiding major modifications of the colonies shortly before application and using larger tunnels with effective crop areas preferably > 80 m². To carry out quicker brood cell assessments to reduce stress for the colonies, it is recommended to use digital brood assessment, which allows marking a higher number of cells (e.g. 200 to 400 cells)

From working collections to the World Germplasm Project: agricultural modernization and genetic conservation at the Rockefeller Foundation

This paper charts the history of the Rockefeller Foundation’s participation in the collection and long-term preservation of genetic diversity in crop plants from the 1940s through the 1970s. In the decades following the launch of its agricultural program in Mexico in 1943, the Rockefeller Foundation figured prominently in the creation of world collections of key economic crops. Through the efforts of its administrators and staff, the foundation subsequently parlayed this experience into a leadership role in international efforts to conserve so-called plant genetic resources. Previous accounts of the Rockefeller Foundation’s interventions in international agricultural development have focused on the outcomes prioritized by foundation staff and administrators as they launched assistance programs and especially their characterization of the peoples and ‘‘problems’’ they encountered abroad. This paper highlights instead how foundation administrators and staff responded to a newly emergent international agricultural concern—the loss of crop genetic diversity. Charting the foundation’s responses to this concern, which developed only after agricultural modernization had begun and was understood to be produced by the successes of the foundation’s own agricultural assistance programs, allows for greater interrogation of how the foundation understood and projected its central position in international agricultural research activities by the 1970s.Research for this article was supported in part by a grant-in-aid from the Rockefeller Archive Center

Haulout site selection by southern elephant seals at Marion Island

Using data from an ongoing mark-resight programme at Marion Island, we tested empirically whether southern elephant seals prefer certain terrestrial sites to others during the breeding, moulting and winter haulouts, and whether the pattern of site use is the same for different age and sex groups. Southern elephant seals preferred some sites, while discriminating against other sites, with different age and sex classes using different sites for certain haulout events. Wintering young animals did not show strong site selection. Some popular sites were used for all haulouts by all age and sex groups, and apparently have all the requirements of a good site for terrestrial haulout by southern elephant seals. Site selection becomes more apparent with age, suggesting the role of haulout experience in site selection

Cerebral palsy and its medicolegal implications in low-resource settings – the need to establish causality and revise criteria to implicate intrapartum hypoxia : a narrative review

The objective of this study was to establish scientific causality and to devise criteria to implicate intrapartum hypoxia in cerebral palsy (CP) in low-resource settings, where there is potential for an increase in damaging medicolegal claims against obstetric caregivers, as is currently the situation in South Africa. For the purposes of this narrative review, an extensive literature search was performed, including any research articles, randomised controlled trials, observational studies, case reports or expert or consensus statements pertaining to CP in low-resource settings, medicolegal implications, causality, and criteria implicating intrapartum hypoxia. In terms of causation, there are differences between high-income countries (HICs) and low-resource settings. While intrapartum hypoxia accounts for 10 - 14% of CP in HICs, the figure is higher in low-resource settings (20 - 46%), indicating a need for improved intrapartum care. Criteria implicating intrapartum hypoxia presented for HICs may not apply to low-resource settings, as cord blood pH testing, neonatal brain magnetic resonance imaging (MRI) and placental histology are frequently not available, compounded by incomplete clinical notes and missing cardiotocography tracings. Revised criteria in an algorithm for low-resource settings to implicate intrapartum hypoxia in neonatal encephalopathy (NE)/ CP are presented. The algorithm relies first on specialist neurological assessment of the child, determination of the occurrence of neonatal encephalopathy (by documented or verbal accounts) and findings on childhood MRI, and second on evidence of antepartum and intrapartum contributors to the apparent hypoxia-related CP. The review explores differences between low-resource settings and HICs in trying to establish causation in NE/CP and presents a revised scientific approach to causality in the context of low-resource settings for reaching appropriate legal judgments.https://samajournals.co.za/index.php/samj/indexam2024Obstetrics and GynaecologyPaediatrics and Child HealthSDG-03:Good heatlh and well-bein

Abundance of Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa

Coastally distributed dolphin species are vulnerable to a variety of anthropogenic pressures, yet a lack of abundance data often prevents data-driven conservation management strategies from being implemented. We investigated the abundance of Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa, from the Goukamma Marine Protected Area (MPA) to the Tsitsikamma MPA, between 2014 and 2016. During this period, 662.3h of boat-based photo-identification survey effort was carried out during 189 surveys. The sighting histories of 817 identified individuals were used to estimate abundance using capture-recapture modelling. Using open population (POPAN) models, we estimated that 2,155 individuals (95% CI: 1,873–2,479) occurred in the study area, although many individuals appeared to be transients. We recorded smaller group sizes and an apparent decline in abundance in a subset of the study area (Plettenberg Bay) compared to estimates obtained in 2002–2003 at this location. We recorded declines of more than 70% in both abundance and group size for a subset of the study area (Plettenberg Bay), in relation to estimates obtained in 2002–2003 at this location. We discuss plausible hypotheses for causes of the declines, including anthropogenic pressure, ecosystem change, and methodological inconsistencies. Our study highlights the importance of assessing trends in abundance at other locations to inform data-driven conservation management strategies of T. aduncus in South Africa.Supporting information: Fig S1. Survey tracks along the study area. Table S1. Search effort per section of the study area, year and season. Table S2. Model selection and abundance estimates for T. aduncus obtained from POPAN open population Jolly-Seber models.http://www.plosone.orgpm2020Mammal Research InstituteZoology and Entomolog