Sleep disorders in children

Although sleep disorders such as insomnia and obstructive sleep apnea are common in both children and adults, the clinical features and treatments for these conditions differ considerably between these two populations. Whereas an adult with obstructive sleep apnea typically presents with a history of obesity, snoring, and prominent daytime somnolence, a child with the condition is more likely to present with normal body weight, tonsillar hypertrophy, and inattentiveness during school classes. The adult with suspected sleep apnea almost always undergoes a baseline polysomnogram and proceeds to treatment only if this test confirms the diagnosis, while many children with suspected sleep apnea are treated empirically with adenotonsillectomy without ever receiving a sleep study to verify the diagnosis. This article reviews sleep disorders in children, with a particular focus on age-related changes in sleep, conditions that primarily affect children, and disorders for which clinical manifestations and treatment differ substantially from the adult population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78712/1/j.1749-6632.2009.05112.x.pd

Slowmation

A slowmation (abbreviated from slow animation ) is a simplified way for university or school students to design and make a stop-motion animation that is played at 2 frames/s providing a slow-moving image that is narrated to explain a science concept (Hoban 2005). It is an innovative way for students to learn science because they engage with a concept in many different ways when creating a slowmation by (i) reading text/images and making summary notes, (ii) creating a storyboard to plan the explanation, (iii) making or using existing models, (iv) taking digital still photos of models as they are manually moved, and (v) using technology to integrate different modes that make up the final animation

Unbounded randomness certification using sequences of measurements

Unpredictability, or randomness, of the outcomes of measurements made on an entangled state can be certified provided that the statistics violate a Bell inequality. In the standard Bell scenario where each party performs a single measurement on its share of the system, only a finite amount of randomness, of at most $4 log_2 d$ bits, can be certified from a pair of entangled particles of dimension $d$. Our work shows that this fundamental limitation can be overcome using sequences of (nonprojective) measurements on the same system. More precisely, we prove that one can certify any amount of random bits from a pair of qubits in a pure state as the resource, even if it is arbitrarily weakly entangled. In addition, this certification is achieved by near-maximal violation of a particular Bell inequality for each measurement in the sequence.Comment: 4 + 5 pages (1 + 3 images), published versio

Local Rigidity of Triangle Groups in Sp(4,R)

This paper studies configurations of Lagrangians in a four dimensional real symplectic vector space. We develop a generalized cross ratio as an invariant for quadruples of Lagrangians. This invariant is then used to study representations of triangle groups into the symplectic group. The main theorem is a local rigidity result for a certain representations factoring through the isometry group of the hyperbolic plane

Faecal microRNAs: indicators of imbalance at the host-microbe interface?

The enteric microbiota is characterised by a balance and composition that is unique to the host. It is important to understand the mechanisms through which the host can maintain the composition of the gut microbiota. MicroRNAs (miRNA) are implicated in intercellular communication and have been isolated from bodily fluids including stool. Recent findings suggest that miRNA produced by the host’s intestinal epithelial cells (IECs) participate in shaping the microbiota. To investigate whether miRNA expression was influenced by the gut microbiota we measured the expression of miRNAs expressed by intestinal epithelial cells in faeces. Specifically, we measured miRNA expression in faeces from germ-free (GF) and conventional mice and similarly in a rat model of antibiotic-mediated depletion of the gut microbiota control rats. In adult male GF and conventional mice and adult Sprague Dawley (SD) rats were treated with a combination of antibiotics for 8 weeks; total RNA was extracted from faecal pellets taken at week 0, 2, 4, 6 week 8 and the expression of let-7b-3p, miR-141-3p, miR-200a-3p and miR-1224-5p (miRNAs known to be expressed in IECs) were measured relative to U6 at each time point using qRT-PCR. In GF animals the expression of let-7b, miR-141 and miR-200a in faeces was lower compared to conventional mice. Following antibiotic-mediated depletion of gut microbiota, rats showed two divergent profiles of miRNA expression. Following two weeks of antibiotic treatment, the expression of let-7b and miR-1224 dropped significantly and remained low for the remainder of the study. The expression of miR-200a and miR-141 was significantly higher at week 2 than before antibiotic treatment commenced. Subsequently, the expression of miR-200a and miR-141 decreased at week 4 and continued to decrease at week 6. This data demonstrates that miRNAs can be used as an independent, non-invasive marker of microbial fluctuations along with gut pathology in the intestine

A role for the orphan nuclear receptor TLX in the interaction between neural precursor cells and microglia

Microglia are an essential component of the neurogenic niche in the adult hippocampus and are involved in the control of neural precursor cell (NPC) proliferation, differentiation and the survival and integration of newborn neurons in hippocampal circuitry. Microglial and neuronal cross-talk is mediated in part by the chemokine fractalkine/chemokine (C-X3-C motif) ligand 1 (CX3CL1) released from neurons, and its receptor CX3C chemokine receptor 1 (CX3CR1) which is expressed on microglia. A disruption in this pathway has been associated with impaired neurogenesis yet the specific molecular mechanisms by which this interaction occurs remain unclear. The orphan nuclear receptor TLX (Nr2e1; homologue of the Drosophila tailless gene) is a key regulator of hippocampal neurogenesis, and we have shown that in its absence microglia exhibit a pro-inflammatory activation phenotype. However, it is unclear whether a disturbance in CX3CL1/CX3CR1 communication mediates an impairment in TLX-related pathways which may have subsequent effects on neurogenesis. To this end, we assessed miRNA expression of up- and down-stream signalling molecules of TLX in the hippocampus of mice lacking CX3CR1. Our results demonstrate that a lack of CX3CR1 is associated with altered expression of TLX and its downstream targets in the hippocampus without significantly affecting upstream regulators of TLX. Thus, TLX may be a potential participant in neural stem cell (NSC)–microglial cross-talk and may be an important target in understanding inflammatory-associated impairments in neurogenesis