Estimating the Frequency of Sexual Reproduction in the Diatom Stephanodiscus niagarae

Diatoms are single-celled micro-algae with cell walls composed of silica, that reproduce in a way that results in a decrease in cell size after each round of mitotic (asexual) division. A cell cannot continue to shrink indefinitely, so when the average size of the population reaches a critical threshold, diatoms reproduce sexually and restore their maximal size. It is unclear, however, how frequently diatoms undergo sexual reproduction in nature. As a proxy for sexual reproduction, I monitored changes in cell size of a population of the diatom Stephanodiscus niagarae from the plankton community of Lake Fayetteville (Arkansas, USA). Weekly sampling during the Fall 2015-Spring 2016 period revealed that S. niagarae is a winter species, occurring after a shift in the planktonic community of Lake Fayetteville, in which populations of warm-water green and blue-green algae decline and are replaced by a diatom-dominated community. S. niagarae first occurred in December, in clear colder water at 10oC or below. Within weeks, this population grew steadily from a few hundred to several thousand cells per milliliter, reaching a maximum density in late January. The population declined rapidly thereafter. Although this decline coincided with increased lake temperature and the proportion of cells infected by a chytrid parasite, it is not clear if these two factors are the proximal cause for S. niagarae declines. Asexual reproduction resulted in substantial variation in average cell size, and an increase in variance towards the end of the growth period. However, the modest variation in median cell diameter of about 5 μm indicated that a synchronous population-wide sexual reproduction event did not occur during the course of the study. These results suggest that the frequency of sexual reproduction in S. niagarae in Lake Fayetteville might be on the order of several to dozens of years. However, the possibility of asynchronous sexual reproduction and a population with overlapping generations cannot be ruled out

Care planning for aggression management in a specialist secure mental health service:user involvement

This paper describes an audit of prevention and management of violence and aggression care plans and incident reporting forms which aimed to: (i) report the compliance rate of completion of care plans; (ii) identify the extent to which patients contribute to and agree with their care plan; (iii) describe de-escalation methods documented in care plans; and (iv) ascertain the extent to which the de-escalation methods described in the care plan are recorded as having been attempted in the event of an incident. Care plans and incident report forms were examined for all patients in men's and women's mental health care pathways who were involved in aggressive incidents between May and October 2012. In total, 539 incidents were examined, involving 147 patients and 121 care plans. There was no care plan in place at the time of 151 incidents giving a compliance rate of 72%. It was documented that 40% of patients had contributed to their care plans. Thematic analysis of de-escalation methods documented in the care plans revealed five de-escalation themes: staff interventions, interactions, space/quiet, activities and patient strategies/skills. A sixth category, coercive strategies, was also documented. Evidence of adherence to de-escalation elements of the care plan was documented in 58% of incidents. The reasons for the low compliance rate and very low documentation of patient involvement need further investigation. The inclusion of coercive strategies within de-escalation documentation suggests that some staff fundamentally misunderstand de-escalation

An arm and a leg for the Confederacy : Virginia\u27s disabled veteran legislation, 1865 to 1888

The Civil War, more than any other conflict in American history, left a legacy of maimed and disabled veterans. In Virginia a social consciousness began to develop during the war which led to both private and public attempts to aid these men. Following the war this philanthropy was continued by the General Assembly with a series of acts intended to provide for the disabled veterans of the Commonwealth. Initially a small scale program to provide artificial limbs to amputees, this initiative quickly expanded to include disabled veterans of all types. It was from this aid program that a general state Confederate pension system developed in 1888. This study examines the early accomplishments of this aid program. In order to provide insight into the individuals assisted by the program, it focuses on the disabled veterans of Augusta and Chesterfield counties. This thesis relies heavily on the records of Virginia\u27s Auditor of Public Accounts, the General Assembly\u27s legislative record, and the manuscript census

Temperature-stable Gunn-diode oscillator

Oscillator consisting of Gunn diode embedded in coaxial circuit has excellent temperature stability and low fabrication costs as compared with automatic-frequency-control crystal oscillators

Neutrons from 9Be/alpha,n/ reaction for E alpha between 6 and 10 MeV

Neutron energy spectra measured as function of neutron emission angle and ion bombardment energ

A C-13(alpha,n)O-16 calibration source for KamLAND

We report on the construction and performance of a calibration source for KamLAND using the reaction C-13(alpha,n)O-16 with Po-210 as the alpha progenitor. The source provides a direct measurement of this background reaction in our detector, high energy calibration points for the detector energy scale, and data on quenching of the neutron visible energy in KamLAND scintillator. We also discuss the possibility of using the reaction C-13(alpha,n)O-16 as a source of tagged slow neutrons.Comment: 6 pages, 4 figures. Revised to agree with the published tex

Cooled Ceramic Matrix Composite Propulsion Structures Demonstrated

NASA's Next Generation Launch Technology (NGLT) Program has successfully demonstrated cooled ceramic matrix composite (CMC) technology in a scramjet engine test. This demonstration represented the world s largest cooled nonmetallic matrix composite panel fabricated for a scramjet engine and the first cooled nonmetallic composite to be tested in a scramjet facility. Lightweight, high-temperature, actively cooled structures have been identified as a key technology for enabling reliable and low-cost space access. Tradeoff studies have shown this to be the case for a variety of launch platforms, including rockets and hypersonic cruise vehicles. Actively cooled carbon and CMC structures may meet high-performance goals at significantly lower weight, while improving safety by operating with a higher margin between the design temperature and material upper-use temperature. Studies have shown that using actively cooled CMCs can reduce the weight of the cooled flow-path component from 4.5 to 1.6 lb/sq ft and the weight of the propulsion system s cooled surface area by more than 50 percent. This weight savings enables advanced concepts, increased payload, and increased range. The ability of the cooled CMC flow-path components to operate over 1000 F hotter than the state-of-the-art metallic concept adds system design flexibility to space-access vehicle concepts. Other potential system-level benefits include smaller fuel pumps, lower part count, lower cost, and increased operating margin

Measuring the violence prevention climate:Development and evaluation of the VPC-14

© 2018 Elsevier Ltd. Background: Violence and aggression are common in inpatient mental health hospital settings and cause problems for staff, patients and organisations. An important factor in treatment efficacy is ward atmosphere, and one element of this is the violence prevention climate. Objectives: To develop and test the psychometric properties of a new scale to measure perceptions of the violence prevention climate among staff and patients in mental health inpatient settings. Design: Scale development and cross-sectional validation study. Setting and participants: Three hospital sites within an independent sector provider of secure mental health care. Participants were patients and staff residing in/working on wards in the adult male and female mental health care pathways. Methods: The study was conducted in three stages: scale development, pilot testing and psychometric evaluation. The scale items were developed from systematic literature review, informant interviews (staff) and focus groups (patients) and expert review. The resulting scale was subject to pilot testing with staff and patients (n = 58 and n = 25). The reliability and validity of the scale was examined by administering it to 326 staff and 95 patients. Exploratory factor analysis was used to establish construct validity, and this was further assessed with Rasch modelling. Internal consistency was assessed by calculation of Cronbach's alpha coefficients. Convergent and discriminant validity were measured by comparing results with existing validated instruments. Temporal stability of the items was assessed using test-retest reliability coefficients. Results: The VPC-14 is a 14-item scale demonstrating good psychometric properties. Exploratory factor analysis revealed two subscales, staff actions and patient actions, each demonstrating good internal consistency (Cronbach's alpha.89 and.76). All items demonstrated good temporal stability. Rasch modelling confirmed the unidimensionality of the two subscales, and items demonstrated high construct validity. Moderate correlations were found between subscales of the VPC-14 and the EssenCES, whilst no correlations were found with items in the ACMQ, thus demonstrating good convergent and discriminant validity. Conclusion: The VPC-14 is currently the most robust available measure of the inpatient violence prevention climate. It is quick and easy to administer, considers views of both staff and patients and thus can be introduced as standard practice in a ward setting. Potential uses include tracking the violence prevention climate longitudinally and in evaluation of new policy and procedural interventions

Examining the utility of the Violence Prevention Climate scale: In a metropolitan Australian general hospital.

AIM AND OBJECTIVES: To evaluate and examine the utility of the Violence Prevention Climate scale by generalist healthcare professionals. BACKGROUND: Workplace violence in general hospital settings remains a challenge for healthcare organisations. High rates of violence are still being reported towards healthcare workers, despite organisational violence prevention strategies being implemented. There is a major challenge to healthcare organisation in the measurement of the effectiveness of these interventions, traditionally completed via the reporting and monitoring of workplace violent incidents. A novel approach to measuring workplace violence is by studying hospital atmosphere or climate. DESIGN: A cross-sectional survey using the STARD guidelines was used. METHODS: The Violence Prevention Climate scale was completed by 194 healthcare staff working in the emergency department, medical/surgical wards, respiratory/infectious disease, spinal care, renal unit, corrections health, and rehabilitation and community services of a major Australian tertiary referral hospital. The Violence Prevention Climate scale has previously been validated and used in mental health settings, but not general hospital settings. A content analysis of an open-ended question on violence prevention management strategies was also conducted. RESULTS: Comprising of 14 items with two factors (patients and staff), the study revealed a 9-item staff factor scale that can be used in the general hospital setting, the patient factor did not show adequate reliability. The content analysis revealed seven categories of staff identified violence prevention and management strategies. CONCLUSIONS: The use of the 9-item scale across an organisation annually, or added to existing organisational workforce surveys, could prove to be practical way of measuring the social climate of violence in a general hospital setting. RELEVANCE TO CLINICAL PRACTICE: The results of which could guide clinical practice, workplace safety, policy and educational initiatives for the prevention and management of workplace violence

Submillimeter satellite radiometer Final engineering report

All solid-state superheterodyne Dicke radiometer for submillimeter wavelength