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Background: Biallelic variants in POLR1C are associated with POLR3-related leukodystrophy (POLR3-HLD), or 4H leukodystrophy (Hypomyelination, Hypodontia, Hypogonadotropic Hypogonadism), and Treacher Collins syndrome (TCS). The clinical spectrum of POLR3-HLD caused by variants in this gene has not been described. Methods: A cross-sectional observational study involving 25 centers worldwide was conducted between 2016 and 2018. The clinical, radiologic and molecular features of 23 unreported and previously reported cases of POLR3-HLD caused by POLR1C variants were reviewed. Results: Most participants presented between birth and age 6 years with motor difficulties. Neurological deterioration was seen during childhood, suggesting a more severe phenotype than previously described. The dental, ocular and endocrine features often seen in POLR3-HLD were not invariably present. Five patients (22%) had a combination of hypomyelinating leukodystrophy and abnormal craniofacial development, including one individual with clear TCS features. Several cases did not exhibit all the typical radiologic characteristics of POLR3-HLD. A total of 29 different pathogenic variants in POLR1C were identified, including 13 new disease-causing variants. Conclusions: Based on the largest cohort of patients to date, these results suggest novel characteristics of POLR1C-related disorder, with a spectrum of clinical involvement characterized by hypomyelinating leukodystrophy with or without abnormal craniofacial development reminiscent of TCS.
This paper evaluates the potential of very high resolution multispectral (Worldview-3) satellite imagery for mapping yield parameters in avocado and macadamia orchards. An evaluation of 18 structural and pigment based vegetation indices (VIs) derived from Worldview-3 imagery identified a positive relationship to nut/ fruit weight (kg/tree) R2>0.69 for macadamia and R2>0.68 for avocado; and nut/ fruit number (per tree) R2>0.6 for macadamia and R2>0.61 for avocado. Using the algorithms derived between the optimal VI and the measured parameter, yield and nut/ fruit number maps were derived for each block. In the absence of a commercial yield monitor, the resulting yield maps offer significant benefit to growers for improving orchard management, harvest scheduling, and forward selling decisions.
The readback/hearback loop is a communicative protocol used in many high-risk environments to ensure that a verbal instruction has been heard correctly by a receiver. However, it does not necessarily ensure that an instruction has been understood. Using an international sample of hydroelectric power generation controllers, this study examined whether particular linguistic (complete and partial readbacks) and prosodic (final intonation, filler, and interturn delay) cues contained within a readback response could signal to listeners the extent to which speakers had understood an instruction. The results indicated that different prosodic cues are used to detect nonunderstandings, depending upon the linguistic content of the readback. The results have implications for training and system design in distributed environments.
Hosts strongly influence parasite fitness. However, it is challenging to disentangle host effects on genetic vs plasticity-driven traits of parasites, since parasites can evolve quickly. It remains especially difficult to determine the causes and magnitude of parasite plasticity. In successive generations, parasites may respond plastically to better infect their current type of host, or hosts may produce generally ‘good’ or ‘bad’ quality parasites. Here, we characterized parasite plasticity by taking advantage of a system in which the parasite (the yeast Metschnikowia bicuspidata, which infects Daphnia) has no detectable heritable variation, preventing rapid evolution. In experimental infection assays, we found an effect of rearing host genotype on parasite infectivity, where host genotypes produced overall high or low quality parasite spores. Additionally, these plastically induced differences were gained or lost in just a single host generation. Together, these results demonstrate phenotypic plasticity in infectivity driven by the within-host rearing environment. Such plasticity is rarely investigated in parasites, but could shape epidemiologically important traits.
Pre-eclampsia is a serious hypertensive condition of pregnancy associated with high maternal and fetal morbidity and mortality. Se intake or status has been linked to the occurrence of pre-eclampsia by our own work and that of others. We hypothesised that a small increase in the Se intake of UK pregnant women of inadequate Se status would protect against the risk of pre-eclampsia, as assessed by biomarkers of pre-eclampsia. In a double-blind, placebo-controlled, pilot trial, we randomised 230 primiparous pregnant women to Se (60 μg/d, as Se-enriched yeast) or placebo treatment from 12 to 14 weeks of gestation until delivery. Whole-blood Se concentration was measured at baseline and 35 weeks, and plasma selenoprotein P (SEPP1) concentration at 35 weeks. The primary outcome measure of the present study was serum soluble vascular endothelial growth factor receptor-1 (sFlt-1), an anti-angiogenic factor linked with the risk of pre-eclampsia. Other serum/plasma components related to the risk of pre-eclampsia were also measured. Between 12 and 35 weeks, whole-blood Se concentration increased significantly in the Se-treated group but decreased significantly in the placebo group. At 35 weeks, significantly higher concentrations of whole-blood Se and plasma SEPP1 were observed in the Se-treated group than in the placebo group. In line with our hypothesis, the concentration of sFlt-1 was significantly lower at 35 weeks in the Se-treated group than in the placebo group in participants in the lowest quartile of Se status at baseline (P= 0·039). None of the secondary outcome measures was significantly affected by treatment. The present finding that Se supplementation has the potential to reduce the risk of pre-eclampsia in pregnant women of low Se status needs to be validated in an adequately powered trial.
An enormous effort is underway worldwide to attempt to detect gravitational waves. If successful, this will open a new frontier in astronomy. An essential portion of this effort is being carried out in Australia by the Australian Consortium for Interferometric Gravitational Astronomy (ACIGA), with research teams working at the Australia National University, University of Western Australia, and University of Adelaide involving scientists and students representing many more institutions and nations. ACIGA is developing ultrastable high-power continuous-wave lasers for the next generation interferometric gravity wave detectors; researching the problems associated with high optical power in resonant cavities; opening frontiers in advanced interferometry configurations, quantum optics, and signal extraction; and is the world's leader in high-performance vibration isolation and suspension design. ACIGA has also been active in theoretical research and modelling of potential astronomical gravitational wave sources, and in developing data analysis detection algorithms. ACIGA has opened a research facility north of Perth, Western Australia, which will be the culmination of these efforts. This paper briefly reviews ACIGA's research activities and the prospects for gravitational wave astronomy in the southern hemisphere.
Fossils of the giant short-faced bear, Arctodus simus (Cope, 1879), have been recovered from over 100 localities in North America, extending from Mexico to Alaska and California to Virginia. Despite this large range, the species has never been recorded from the southeastern United States. The lesser short-faced bear, Arctodus pristinus Leidy, 1854 is well represented from this region, particularly Florida, but all known occurrences are late Pliocene – middle Pleistocene in age (about 2.5 to 0.3 Ma). Differentiating A. simus from A. pristinus can be difficult because large individuals of A. pristinus overlap in size with small individuals of A. simus, and there are few morphological differences. However, these two taxa can be clearly separated based on the relative proportions of their molars and premolars. Two Pleistocene records of A. simus representing a minimum of three individuals from the Withlacoochee River drainage of central Florida are reported here, substantially extending the distribution of this massive bear into southeastern North America. A late Pleistocene age for these occurrences is corroborated by an associated Rancholabrean fauna and rare earth elemental analyses. One of the reported individuals is quite large, supporting the hypothesis of extreme sexual dimorphism in A. simus and rejecting a hypothesis of two subspecies.
Oocytes from (C3H/HeH × 101/H)F1 and Rb(16.17)7Bnr homozygous females were exposed to a range of doses of nocodazole in vitro. The spindle poison caused a dose dependent increase in metaphase I (MI) arrest and hyperploidy. A concentration of 0·03 μg/ml was found to induce a maximum hyperploid frequency of 3·1% and 11·6% respectively without a high level of MI arrest. Between 0·03 and 0·05 μg/ml MI arrest increased substantially and reached a frequency of approximately 90%. In a further experiment oocytes from Rb7 homozygous, heterozygous and 3H1 females were exposed to 0·03 μg/ml nocodazole 4, 6 or 8 h after the onset of maturation. The phase at which the spindle was inhibited resulted in a specific pattern of nondisjunction which in turn was dependent on whether the female carried an Rb metacentric. 3H1 oocytes gave a normally distributed pattern of increase in aneuploid frequency (over the spontaneous value) centering around a 6 h application. This was thought to be due to the interaction of chromosomes with the microtubules of the spindle during attachment and/or alignment. In contrast both Rb homozygotes and heterozygotes gave the same biphasic response, with a high frequency of aneuploidy in the oocytes when nocodazole was applied 4 and 8 h after the onset of maturation. In Rb homozygotes we demonstrated that the Rb bivalent underwent nondisjunction more frequently than the average acrocentric, when nocodazole was administered early. It can be assumed that the Rb trivalent in Rb heterozygotes showed a similar response. This early Rb specific effect, in combination with a delayed-version of the acrocentric effect found in the 3H1 mice was thought to generate the biphasic pattern. We discuss the implications of (a) the different meiotic behaviours of metacentrics and acrocentrics and (b) the meiotic delay in Rb mice.
If heterozygotes for a reciprocal translocation are intercrossed, some of their viable balanced progeny result from the fusion of unbalanced gametes with complementary duplications and deficiencies of the translocated segments. Therefore, if one parent in such an intercross is homozygous for a genetic marker on one of the segments concerned, some homozygous offspring will be produced even if the other parent does not have the marker. The expected frequency of such exceptional offspring among live-born is one-sixth if the marker is on the distal (non-centromeric) side of the point of exchange and single chiasmata normally occur in each interstitial segment. Much lower frequencies are expected if the marker is on the centromeric side, since duplications and deficiencies of proximal segments occur only as a consequence of adjacent-2 disjunction, in which homologous centromeres proceed to the same pole. This is rarer than normal disjunction. Thus, by comparing the frequencies of offspring homozygous for markers on one or other side of the point of exchange, it is possible (i) to determine which marker is in the centromeric segment, (ii) to estimate the frequency of adjacent-2 disjunction, given information on the nature of meiotic configurations in the translocation concerned.
By this method, it is shown that the frequency of adjacent-2 disjunction is similar in heterozygotes for mouse translocations (T5;18)26H, T(13; ?) 70H and T(14;17)264Ca, averaging 13%. Centromeres were located at the Sd end of linkage group V (confirming previous findings), the fz end of XIII and the bg end of XIV.
Frequencies of anaphase I nondisjunction, germ cell death and pairing abnormalities at pachytene were assessed in male mice singly heterozygous and homozygous for the Robertsonian (Rb) translocations: Rb (1.3)lBnr, Rb(ll. 13)4Bnr and Rb(10. ll)8Bnr. Rb homozygotes showed low frequencies of nondisjunction but substantial germ cell death. This germ cell death could not be attributed to problems at pachytene as Rb homozygotes showed no increase in pairing abnormalities over the (C3H/HeH×1O1/H)F1 controls. Instead genie factors are involved. Rb heterozygotes showed substantial frequencies of nondisjunction and even greater germ cell death than found in the homozygotes. Pachytene pairing abnormalities were observed and it appears that these, together with genie factors, cause physiological perturbation of meiocytes, thereby promoting germ cell death, with nondisjunction of the trivalent as a sublethal response.
The steel allele, contrasted (Slcon), arose in a neutron irradiation experiment. Slcon is fully penetrant and heterozygotes can be recognized at or soon after birth by darkly pigmented external genitalia in both sexes, while the adult coat tends to be a little lighter than normal. Homozygotes also have dark genitalia and a markedly diluted coat. Both eumelanin and phaeomelanin are affected, with reduced numbers of cortical and medullary pigment granules in the hairs. Contrasted also affects the haematopoietic system, causing slight macrocytic anaemia in the homozygote. Slcon homozygous males are fertile but testes weigh on average 20% less than in their heterozygous litter-mates. Homozygous females are usually sterile although if mated early (4½−6 weeks) they occasionally have a single litter. Ovarian sections showed a gradual degeneration of oocytes in Graafian follicles so that most had gone by 2 months. Similarly, vaginal smears indicated that after about three normal cycles homozygous females lapsed into a state of persistent dioestrus; injections with gonadotrophins did not prolong their period of fertility or cause a resumption of their oestrous cycles. The effects on fertility, pigmentation and haematology of contrasted when combined with other steel alleles are also described.
Many areas of rain forest now exist as habitat fragments, and understanding the impacts of fragmentation is important for determining the viability of populations within forest remnants. We investigated impacts of forest fragmentation on genetic diversity in the butterfly Mycalesis orseis (Satyrinae) in Sabah (Malaysian Borneo). We investigated mtDNA diversity in 90 individuals from ten forest sites typical of the sizes of forest remnants that currently exist in the region. Nucleotide diversity declined with increasing isolation of remnants, but there was no effect of remnant size or population size, and haplotype diversity was similar among sites. Thus, approximately 50 y after forest fragmentation, few changes in genetic diversity were apparent and remnants apparently supported genetically viable populations of this butterfly. Many studies have shown that responses of species to habitat fragmentation usually follow a time delay, and so we developed a Monte Carlo simulation model to investigate changes in genetic diversity over time in small remnants. Model output indicated a substantial time delay (> 100 y) between fragmentation and genetic erosion, suggesting that, in the smallest study remnants, an increased risk of extinction from reduced genetic diversity is likely in the longer term.
An unusual chromosomal hybrid zone of the house mouse, Mus musculus domesticus, exists in Upper Valtellina, Northern Italy, consisting of four Robertsonian (Rb) races and the standard (all-acrocentric, or 2n = 40) race, all hybridizing freely within 10 km2. The hybrid zone in Valtellina provides an excellent opportunity to study the role of Rb fusions in reproductive isolation and speciation. This hybrid zone has already been well studied for the distribution of Rb fusions and the fertility of hybrids, but in order to understand the dynamics of the zone, a basic understanding of the origin and genetic similarity of the chromosomal races is necessary. This paper presents the results of three different methods of measuring genetic differentiation: multivariate analysis of morphological traits and analyses of allozyme variation and mitochondrial DNA sequences. The standard race is clearly distinguishable from the three Rb races by all three methods, but the Rb races are not distinguishable from one another. This provides strong evidence for our previous suggestions that the well-established Rb races in Valtellina are closely related, and that the standard race was introduced into the valley more recently from a distant source. The fact that the Rb races are indistinguishable is also consistent with our hypothesis that a within-village speciation event involving two of the races (Hauffe & Searle, 1992) was a recent occurrence. The low level of allozyme heterozygosity among the Rb races suggests that these populations are the products of at least one bottleneck. The present article substantially extends earlier studies and provides the first detailed morphological and molecular analysis of this complex hybrid zone.
We report a U–Pb monazite age of 23.0±0.2 Ma for the Shivling leucogranite, a
tourmaline+muscovite±biotite leucogranite at the top of the High Himalayan slab in the Garhwal
Himalaya, north India. The Shivling–Bhagirathi leucogranite is a viscous near-minimum melt,
emplaced as a foliation parallel laccolith via a dyke network not far from its source region. Prograde
heating occurred soon after the India–Asia collision at c. 50 Ma up to melting at 23 Ma and high
temperatures (>550 °C) were maintained for at least 15 Ma after garnet growth. The leucogranite was
emplaced at mid-crustal depths along the footwall of the Jhala fault, a large-scale low-angle normal
fault, part of the South Tibetan Detachment system, above kyanite and sillimanite grade gneisses. The
geometry of the leucogranite laccolith shows biaxial extension and boudinage both perpendicular
(north-northeast–south-southwest) and parallel to the strike (west-northwest–east-southeast) of the
mountain range. Unroofing occurred by underthrusting beneath the High Himalayan slab along the
Main Central Thrust zone, progressively ‘jacking up’ the leucogranites, removal of material above by
low-angle normal faulting, and erosion. Very rapid cooling at rates of 200–350 °C/Ma between
23–21 Ma immediately followed crystallization, as tectonic unroofing and erosion removed 24–28 km
of overburden during this time. K–Ar muscovite ages are 22±1.0 Ma and fission track ages of zircons
from >5000 m on the North Ridge of Shivling are 14.2±2.1 and 8.8±1.2 Ma and apatites are
3.5±0.79 and 2.61±0.23 Ma. Slow steady state cooling at rates of 20–30 °C/Ma from 20–1 Ma shows
that maximum erosion rates and unroofing of the leucogranite occurred during the early Miocene.
This timing coincides with initiation of low-angle, north-dipping normal faulting along the South
Tibetan Detachment system.
We, David Johnston and Susan C. Searls, have several common bonds: growing up Deaf in Deaf families, having Deaf children, and working at the National Technical Institute for the Deaf (NTID), located in Rochester, New York, the only technical college for the deaf in the world. We considered ourselves as being unique at the workplace because only a few of us have both Deaf parents and children. Even though we both grew up in Deaf families in the 1950s and 1960s our experiences differed quite considerably. In those times, there were no TTYs (the teletypewriter, a device that enables deaf people to communicate through phone lines), no closed captioned television programs, no legislation mandating increased interpreter services, nor were deaf people viewed as a cultural and linguistic minority. Growing up in two different geographic locations, each of us went to different types of schools: one went to a manual program which used sign language for instruction and the other went to an oral program which used only speech as the mode of instruction. For our college educations, we chose the opposite directions. We shared our experiences and visions in an ASL conversation.
DJ: We'll start with the topic of family experiences. I grew up in a Deaf family. I was the oldest of four children (the other three were sisters); the third child was hearing. My parents had attended residential schools for the Deaf. They attended Gallaudet where they met. […]
The genus Manihot, which comprises a large number of ill-defined species, is of the family Euphorbiaceae. Rogers & Appan (1970), applying taximetric methods, classified the genus into 75 species. All have 36 chromosomes and all show regular bivalent pairing, but there is evidence of polyploidy (Jennings, 1976). Magoon, Krishnan & Bai (1969) suggest that Manihot species are segmental allotetraploids.
Cassava, Manihot esculenta, is not known in the wild state. It may be crossed with a number of Manihot species. Rogers & Appan (1970) nominate three groups, each with two to ten members, that are related to cassava. The closest relatives appear to be M. aesculifolia, M. rubricaulis and M. pringlei.
Purseglove (1968) distinguished cassava cultivars by two criteria: hydrocyanic acid (HCN) content and maturity time. On the basis of HCN, cultivars may broadly be divided into: sweet cassavas, of low HCN content, in which HCN is confined to the phelloderm of the tubers; and bitter cassavas, of high HCN content, in which HCN is usually distributed throughout the tuber. However, the distinction has no taxonomic basis (Nye, 1991). Levels of HCN do not correspond with any other known morphological or ecological feature, except for the very general relationship to maturity time given below.
On the basis of maturity, cultivars may be divided into:
Short-season types that mature in 6–11 months and which cannot be left in the ground for longer than 9–11 months without serious deterioration; these are often sweet cassavas.