Needle-like structures discovered on positively charged lightning branches.

Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends-called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30-300-megahertz frequency band2-8 that can be remotely sensed and imaged with high spatial and temporal resolution9-11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13-15, and exhibits a pattern that is different from that of negative leaders11-13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18-20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20-22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures-which we call 'needles'-that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.

Effects of person-centred planning and practices on the health and well-being of adults with intellectual and developmental disabilities: a multilevel analysis of linked administrative and survey data.

BACKGROUND: A person-centred service planning and practice approach (PCP) is one that is driven by service users' individual preferences, needs and priorities. The approach has been identified as a best practice and is codified in US policies that encourage and, in some contexts, require state systems of home and community-based services to adopt and demonstrate person-centred practice. However, there is insufficient research on PCP's direct impact on outcomes for service users. This study aims to contribute to the evidence base in this area by investigating the association between service experiences and outcomes of adults with intellectual and developmental disabilities (IDD) receiving state-funded services. METHODS: The data for the study come from the 2018-2019 National Core Indicators® In-Person Survey that links survey responses with administrative records for a sample of 22 000 adults with IDD receiving services from 37 state developmental disabilities (DD) systems. Associations among service experiences and outcomes of survey participants are examined through multilevel regression techniques that include participant-level responses and state-level measures of PCP. The state-level measures are constructed by combining administrative records describing participants' service plans with the priorities and goals they expressed in response to the survey. RESULTS: Case managers' (CM) accessibility and attentiveness to individual preferences, as reported by survey participants, are significantly associated with self-reported outcomes such as perceived control over life decisions and sense of health and well-being. Controlling for participants' experiences with their CMs, their reports of the person-centred content of their service plans have net positive associations with outcomes. After accounting for experiences with the service system as reported by participants, the state system's person-centred orientation, measured by the extent to which service plans across the state reflect participants' wishes for improving their social connections, remains a significant predictor of participants' sense of control over their daily lives. CONCLUSIONS: This study contributes to the evidence base supporting PCP as a service model by identifying pathways that link person-centred service planning and delivery and person-centred orientation of state systems to positive outcomes reported by adults with IDD and by demonstrating the value of linking survey and administrative data. The key implication of the findings for policy and practice is that an overall person-centred orientation of state DD systems as well as PCP training for people who support planning for and delivery of direct supports will substantially improve the lives of adults with IDD.

Radio Emission Reveals Inner Meter-Scale Structure of Negative Lightning Leader Steps.

We use the Low Frequency Array (LOFAR) to probe the dynamics of the stepping process of negatively charged plasma channels (negative leaders) in a lightning discharge. We observe that at each step of a leader, multiple pulses of vhf (30-80 MHz) radiation are emitted in short-duration bursts (<10 µs). This is evidence for streamer formation during corona flashes that occur with each leader step, which has not been observed before in natural lightning and it could help explain x-ray emission from lightning leaders, as x rays from laboratory leaders tend to be associated with corona flashes. Surprisingly, we find that the stepping length is very similar to what was observed near the ground, however with a stepping time that is considerably larger, which as yet is not understood. These results will help to improve lightning propagation models, and eventually lightning protection models.

Personal characteristics and outcomes of individuals with developmental disabilities who need support for self-injurious behaviour.

BACKGROUND: For people with intellectual and developmental disabilities, self-injurious behaviour (SIB) can have serious negative effects on both health and quality of life. This descriptive analysis will provide information on the characteristics and outcomes of a subsample of individuals who are identified as needing some or extensive support for SIB in the National Core Indicators Adult Consumer Survey sample. METHODS: The data for this analysis come from states that participated in the 2015-2016 data collection cycle of National Core Indicators Adult Consumer Survey which is a face-to-face survey of adults receiving services through state developmental disability agencies. RESULTS: The characteristics and outcomes of individuals who need at least some support for SIB differ from those of individuals with intellectual and developmental disabilities who do not need support for SIB. Individuals with SIB support needs, for example, tend to live in more structured settings, have fewer relationships, less inclusion in their communities and poorer employment outcomes. CONCLUSIONS: The exploratory descriptive analysis concludes with suggested recommendations for more standardised definitions of SIB in public systems, enhanced behaviour plan protocols and the need for additional research.

Determining Electric Fields in Thunderclouds With the Radiotelescope LOFAR.

An analysis is presented of electric fields in thunderclouds using a recently proposed method based on measuring radio emission from extensive air shower events during thunderstorm conditions. This method can be regarded as a tomography of thunderclouds using cosmic rays as probes. The data cover the period from December 2011 till August 2014. We have developed an improved fitting procedure to be able to analyze the data. Our measurements show evidence for the main negative-charge layer near the -10° isotherm. This we have seen for a winter as well as for a summer cloud where multiple events pass through the same cloud and also the vertical component of the electric field could be reconstructed. On the day of measurement of some cosmic-ray events showing evidence for strong fields, no lightning activity was detected within 100 km distance. For the winter events, the top heights were between 5 and 6 km, while in the summer, typical top heights of 9 km were seen. Large horizontal components in excess of 70 kV/m of the electric fields are observed in the middle and top layers.

LOFAR Lightning Imaging: Mapping Lightning With Nanosecond Precision.

Lightning mapping technology has proven instrumental in understanding lightning. In this work we present a pipeline that can use lightning observed by the LOw-Frequency ARray (LOFAR) radio telescope to construct a 3-D map of the flash. We show that LOFAR has unparalleled precision, on the order of meters, even for lightning flashes that are over 20 km outside the area enclosed by LOFAR antennas (∼3,200 km2), and can potentially locate over 10,000 sources per lightning flash. We also show that LOFAR is the first lightning mapping system that is sensitive to the spatial structure of the electrical current during individual lightning leader steps.

Hypnosis instead of general anaesthesia in paediatric radiotherapy: report of three cases.

PURPOSE: This report proposes hypnosis as a valid alternative to general anaesthesia for immobilisation and set-up in certain cases in paediatric radiotherapy. METHODS: We report three cases of children who underwent radiotherapy in 1994 and were treated using hypnosis for set-up during irradiation. The first and the second were two cases of macroscopic resection of cerebellar medulloblastoma in which craniospinal irradiation was necessary, while the third patient suffered of an endorbitary relapse of retinoblastoma previously treated with bilateral enucleation, radiotherapy and chemotherapy; in this last situation the child needed radiation as palliative therapy. Hypnosis was used during treatment to obtain the indispensable immobility. Hypnotic conditioning was obtained by our expert psychotherapist while the induction during every single treatment was made by the clinician, whose voice was presented to the children during the conditioning. RESULTS: Every single fraction of the radiation therapy was delivered in hypnosis and without the need for narcosis. CONCLUSIONS: Hypnosis may be useful in particular situations to prepare paediatric cancer patients during irradiation, when lack of child collaboration might necessitate the use of general anaesthesia and when anaesthesia itself is not possible.

Organotin complexes with pyrrole-2-carboxaldehyde monoacylhydrazones. Synthesis, spectroscopic properties, antimicrobial activity, and genotoxicity.

A series of organotin complexes with pyrrole-2-carboxaldehyde 2-hydroxybenzoylhydrazone (H3mfps) and pyrrole-2-carboxaldehyde 2-picolinoylhydrazone (H2mfpp) was investigated. The IR, 1H, and 119Sn nuclear magnetic resonance spectroscopic characterization of all the compounds is reported and discussed in connection with the ligand behaviour of the hydrazone and the structure of the organotin complex. Complexes exhibit antibacterial properties higher than those of the corresponding ligands but they turn out to be less potent than the parent organotin compounds. Sn(H3mfps) (C6H5)2Cl2.2H2O and Sn(Hmfpp)(n-C4H9)2Cl are the most active antibacterial compounds showing MIC values between 3-6 micrograms/ml against Bacillus subtilis and Staphylococcus aureus and between 6-25 micrograms/ml against Escherichia coli; the first compound also strongly inhibits the growth of Aspergillus niger. All the ligands and complexes are devoid of DNA-damaging activity in the Bacillus subtilis rec-assay. H2mfpp and its complexes Sn(Hmfpp)(C2H5)2Cl and Sn3(Hmfpp)(mfpp) (C6H5)3Cl6 are shown by the Salmonella-microsome assay to be mutagenic substances in the presence of a metabolic activation system. The obtained results are discussed on the basis of structure-activity relationships.

Organotin complexes with pyrrole-2,5-dicarboxaldehyde bis(acylhydrazones). Synthesis, structure, antimicrobial activity and genotoxicity.

Mono- and bimetallic organotin complexes with pyrrole-2,5-dicarboxaldehyde bis(2-hydroxybenzoylhydrazone) (H5dfps) and pyrrole-2,5-dicarboxaldehyde bis(2-picolinoylhydrazone) (H3dfpp) were synthesized and characterized by IR, 1H and 119Sn NMR spectroscopy. X-ray analysis of the complex [Sn(H3dfps)(C6H5)2].(CH3)2SO revealed a pentacoordination around tin through a N,N,O terdentate ligand behaviour of the hydrazone. This complex is the most active compound, exhibiting MIC values of 3 and 12 micrograms/ml against Gram positive and Gram negative bacteria, respectively. None of the ligands or complexes produced DNA-damage in the Bacillus subtilis rec-assay or showed mutagenic activity in the Salmonella-microsome test.