Formal water oxidation turnover frequencies from MIL-101(Cr) anchored Ru(bda) depend on oxidant concentration.

PubMed

Bhunia, Asamanjoy; Johnson, Ben A; Czapla-Masztafiak, Joanna; Sá, Jacinto; Ott, Sascha

2018-06-21

The molecular water oxidation catalyst [Ru(bda)(L)2] has been incorporated into pyridine-decorated MIL-101(Cr) metal-organic frameworks. The resulting MIL-101@Ru materials exhibit turnover frequencies (TOFs) up to ten times higher compared to the homogenous reference. An unusual dependence of the formal TOFs on oxidant concentration is observed that ultimately arises from differing amounts of catalysts in the MOF crystals being active.

The impact of turnover among respiratory care practitioners in a health care system: frequency and associated costs.

PubMed

Stoller, J K; Orens, D K; Kester, L

2001-03-01

Retention of respiratory therapists (RTs) is a desired institutional goal that reflects department loyalty and RTs' satisfaction. When RTs leave a department, services are disrupted and new therapists must undergo orientation and training, which requires time and expense. Despite the widely shared goal of minimal turnover, neither the annual rate nor the associated expense of turnover for RTs has been described. Determine the rate of RT turnover and the costs related to training new staff members. The Cleveland Clinic Health System is composed of 9 participating hospitals, which range from small, community-based institutions to large, tertiary care institutions. To elicit information about annual turnover among RTs throughout the system, we conducted a survey of key personnel in each of the hospitals' respiratory therapy departments. To calculate the costs of training, we reviewed the training schedule for an RT joining the Respiratory Therapy Section at the Cleveland Clinic Hospital. Cost estimates reflect the duration of training by various supervisory RTs, their respective wages (including benefit costs), and educational materials used in training and orientation. Turnover rates ranged from 3% to 18% per year. Five of the 8 institutions from which rates were available reported rates greater than 8% per year. The rate of annual turnover correlated significantly with the ratio of hospital beds to RT staff (Pearson r = 0.784, r(2) = 0.61, p = 0.02). The cost of training an RT at the Cleveland Clinic Hospital totaled $3,447.11. Turnover among respiratory therapists poses a substantial problem because of its frequency and expense. Greater attention to issues affecting turnover and to enhancing retention of RTs is warranted.

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koven, C. D.; Chambers, J. Q.; Georgiou, K.

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

DOE PAGES

Koven, C. D.; Chambers, J. Q.; Georgiou, K.; ...

2015-09-07

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

REGIONAL DYNAMICS OF WETLAND-BREEDING FROGS AND TOADS: TURNOVER AND SYNCHRONY

EPA Science Inventory

We used data from a statewide frog monitoring network to investigate population turnover and synchrony in eight wetland-breeding species. We found that subpopulations at many sites turn over frequently, with breeding choruses absent or undetectable in most years. Frequencies of d...

Enhanced ozone production in a pulsed dielectric barrier discharge plasma jet with addition of argon to a He-O2 flow gas

NASA Astrophysics Data System (ADS)

Sands, Brian; Ganguly, Biswa; Scofield, James

2013-09-01

Ozone production in a plasma jet DBD driven with a 20-ns risetime unipolar pulsed voltage can be significantly enhanced using helium as the primary flow gas with an O2 coflow. The overvolted discharge can be sustained with up to a 5% O2 coflow at <20 kHz pulse repetition frequency at 13 kV applied voltage. Ozone production scales with the pulse repetition frequency up to a ``turnover frequency'' that depends on the O2 concentration, total gas flow rate, and applied voltage. For example, peak ozone densities >1016 cm-3 were measured with 3% O2 admixture and <3 W input power at a 12 kHz turnover frequency. A further increase in the repetition frequency results in increased discharge current and 777 nm O(5 P) emission, but decreased ozone production and is followed by a transition to a filamentary discharge mode. The addition of argon at concentrations >=5% reduces the channel conductivity and shifts the turnover frequency to higher frequencies. This results in increased ozone production for a given applied voltage and gas flow rate. Time-resolved Ar(1s5) and He(23S1) metastable densities were acquired along with discharge current and ozone density measurements to gain insight into the mechanisms of optimum ozone production.

Treatment staff turnover in organizations implementing evidence-based practices: Turnover rates and their association with client outcomes

PubMed Central

Garner, Bryan R.; Hunter, Brooke D.; Modisette, Kathryn C.; Ihnes, Pamela C.; Godley, Susan H.

2011-01-01

High staff turnover has been described as a problem for the substance use disorder treatment field. This assertion is based primarily on the assumption that staff turnover adversely impacts treatment delivery and effectiveness. This assumption, however, has not been empirically tested. In this study, we computed annualized rates of turnover for treatment staff (n=249) participating in an evidence-based practice implementation initiative and examined the association between organizational-level rates of staff turnover and client-level outcomes. Annualized rates of staff turnover were 31% for clinicians and 19% for clinical supervisors. Additionally, multilevel analyses did not reveal the expected relationship between staff turnover and poorer client-level outcomes. Rather, organizational-level rates of staff turnover were found to have a significant positive association with two measures of treatment effectiveness: less involvement in illegal activity and lower social risk. Possible explanations for these findings are discussed. PMID:22154040

Catalytic hydrogenation of carbon dioxide using Ir(III)-pincer complexes.

PubMed

Tanaka, Ryo; Yamashita, Makoto; Nozaki, Kyoko

2009-10-14

Catalytic hydrogenation of carbon dioxide in aqueous potassium hydroxide was performed using a newly synthesized isopropyl-substituted PNP-pincer iridium trihydride complex as a catalyst. Potassium formate was obtained with turnover numbers up to 3,500,000 and a turnover frequency of 150,000 h(-1), both of which are the highest values reported to date.

Mentor program boosts new nurses' satisfaction and lowers turnover rate.

PubMed

Fox, Kathy C

2010-07-01

In 2004, the turnover rate among first-year registered nurses (RNs) at St. Francis Hospital and Health Centers had mushroomed to 31%. Based on research, in 2006, the hospital embarked on a journey to implement an RN mentor program to improve satisfaction and reduce turnover. A pilot program was initiated, including 12 RN mentors and 12 RN protégés from select nursing units. The results showed a 0% turnover rate during the 1-year pilot program. Based on these findings, the mentor program was expanded to include RNs working in inpatient nursing units and surgery and emergency departments. Each year, the RN turnover rate has decreased. In 2009, the turnover rate was 10.3%. Because of the success of the program, it has been expanded in scope to include other professionals experiencing high turnover in targeted departments, including radiological technicians, respiratory therapists, pharmacists, and physical therapists.

Will they stay or will they go? The role of job embeddedness in predicting turnover in individualistic and collectivistic cultures.

PubMed

Ramesh, Anuradha; Gelfand, Michele J

2010-09-01

Although turnover is an issue of global concern, paradoxically there have been few studies of turnover across cultures. We investigated the cross-cultural generalizability of the job embeddedness model (Mitchell & Lee, 2001) by examining turnover in an individualistic country (United States) and a collectivistic country (India). Using cross-cultural data from call centers (N = 797), we demonstrated that although organization job embeddedness predicted turnover in both countries, different dimensions of job embeddedness predicted turnover in the United States and India. As hypothesized, on the basis of individualism-collectivism theory, person-job fit was a significant predictor of lower turnover in the United States, whereas person-organization fit, organization links, and community links were significant predictors of lower turnover in India. We also explored whether a newly developed construct of embeddedness-family embeddedness-predicts turnover above and beyond job embeddedness and found initial support for its utility in both the United States and India. Theoretical and practical implications are discussed. Copyright 2010 APA, all rights reserved

How Serious of a Problem is Staff Turnover in Substance Abuse Treatment? A Longitudinal Study of Actual Turnover1

PubMed Central

Eby, Lillian T.; Burk, Hannah; Maher, Charleen P.

2010-01-01

In the substance abuse treatment field, the annual turnover rate is cited as being anywhere between 19 and 50 percent (Johnson & Roman, 2002; Gallon, Gabriel, & Knudsen, 2003; Knudsen et al., 2003; McLellan et al., 2003). However, no research to date has evaluated these claims by tracking turnover longitudinally using organizational turnover data from substance abuse treatment centers. This research presents the results of a longitudinal study designed to systematically examine actual turnover among counselors and clinical supervisors. Twenty-seven geographically dispersed treatment organizations, serving a wide range of clients in the public and private sector, provided data for the study over a two year time span (2008–2009). The annual turnover rate was 33.2% for counselors and 23.4% for clinical supervisors. For both groups the majority of turnover was voluntary (employee-initiated). Specific reasons for turnover were largely consistent across the two groups, with the most common reason being a new job or new opportunity. The findings are discussed in terms of the unique employment context of substance abuse treatment. Practical recommendations are also discussed to help stem the tide of turnover in the field of substance abuse treatment. PMID:20675097

Evidence for shock-shock interaction in the jet of CTA 102

NASA Astrophysics Data System (ADS)

Fromm, C. M.; Perucho, M.; Savolainen, T.; Ros, E.; Lobanov, A. P.; Zensus, J. A.; Lähteenmäki, A.

2011-02-01

We have found evidence for interaction between a standing and a traveling shock in the jet of the blazar CTA 102. Our result is based in the study of the spectral evolution of the turnover frequency-turnover flux density (νm, Sm) plane. The radio/mm light curves were taken during a major radio outburst in April 2006.

Effect of staff turnover on staffing: A closer look at registered nurses, licensed vocational nurses, and certified nursing assistants.

PubMed

Kash, Bita A; Castle, Nicholas G; Naufal, George S; Hawes, Catherine

2006-10-01

We examined the effects of facility and market-level characteristics on staffing levels and turnover rates for direct care staff, and we examined the effect of staff turnover on staffing levels. We analyzed cross-sectional data from 1,014 Texas nursing homes. Data were from the 2002 Texas Nursing Facility Medicaid Cost Report and the Area Resource File for 2003. After examining factors associated with staff turnover, we tested the significance and impact of staff turnover on staffing levels for registered nurses (RNs), licensed vocational nurses (LVNs) and certified nursing assistants (CNAs). All three staff types showed strong dependency on resources, such as reimbursement rates and facility payor mix. The ratio of contracted to employed nursing staff as well as RN turnover increased LVN turnover rates. CNA turnover was reduced by higher administrative expenditures and higher CNA wages. Turnover rates significantly reduced staffing levels for RNs and CNAs. LVN staffing levels were not affected by LVN turnover but were influenced by market factors such as availability of LVNs in the county and women in the labor force. Staffing levels are not always associated with staff turnover. We conclude that staff turnover is a predictor of RN and CNA staffing levels but that LVN staffing levels are associated with market factors rather than turnover. Therefore, it is important to focus on management initiatives that help reduce CNA and RN turnover and ultimately result in higher nurse staffing levels in nursing homes.

Insights into public export promotion programs in an emerging economy: the case of Malaysian SMEs.

PubMed

Ayob, Abu H; Freixanet, Joan

2014-10-01

This study evaluates the impact of public export promotion programs (EPPs) among small and medium-sized enterprises (SMEs) in Malaysia. Three indicators, level of awareness, frequency of use, and perception of usefulness, were examined according to a firm's export status. The global evaluation suggests that exporters are more frequent users of EPPs and perceive them to be more useful than non-exporters. Nonetheless, both groups demonstrate higher levels of awareness, are frequent users, and perceive the programs relating to export info/knowledge are more usefulness than programs relating to financial assistance. Further analysis also reveals that the frequency of use and the perception of usefulness for most programs are positively related to export experience, but not to export turnover. This study offers insights into the effectiveness of export programs for encouraging export initiation and expansion in an emerging economy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exploring the Variability of the Flat-spectrum Radio Source 1633+382. II. Physical Properties

NASA Astrophysics Data System (ADS)

Algaba, Juan-Carlos; Lee, Sang-Sung; Rani, Bindu; Kim, Dae-Won; Kino, Motoki; Hodgson, Jeffrey; Zhao, Guang-Yao; Byun, Do-Young; Gurwell, Mark; Kang, Sin-Cheol; Kim, Jae-Young; Kim, Jeong-Sook; Kim, Soon-Wook; Park, Jong-Ho; Trippe, Sascha; Wajima, Kiyoaki

2018-06-01

The flat-spectrum radio quasar 1633+382 (4C 38.41) showed a significant increase of its radio flux density during the period 2012 March–2015 August, which correlates with γ-ray flaring activity. Multi-frequency simultaneous very long baseline interferometry (VLBI) observations were conducted as part of the interferometric monitoring of gamma-ray bright active galactic nuclei (iMOGABA) program and supplemented with additional radio monitoring observations with the OVRO 40 m telescope, the Boston University VLBI program, and the Submillimeter Array. The epochs of the maxima for the two largest γ-ray flares coincide with the ejection of two respective new VLBI components. Analysis of the spectral energy distribution indicates a higher turnover frequency after the flaring events. The evolution of the flare in the turnover frequency-turnover flux density plane probes the adiabatic losses in agreement with the shock-in-jet model. The derived synchrotron self-absorption magnetic fields, of the order of 0.1 mG, do not seem to change dramatically during the flares, and are much weaker, by a factor 104, than the estimated equipartition magnetic fields, indicating that the source of the flare may be associated with a particle-dominated emitting region.

Effects of breeder turnover and harvest on group composition and recruitment in a social carnivore

USGS Publications Warehouse

Ausband, David E.; Mitchell, Michael S.; Waits, Lisette P.

2017-01-01

Breeder turnover can influence population growth in social carnivores through changes to group size, composition and recruitment.Studies that possess detailed group composition data that can provide insights about the effects of breeder turnover on groups have generally been conducted on species that are not subject to recurrent annual human harvest. We wanted to know how breeder turnover affects group composition and how harvest, in turn, affects breeder turnover in cooperatively breeding grey wolves (Canis lupus Linnaeus 1758).We used noninvasive genetic sampling at wolf rendezvous sites to construct pedigrees and estimate recruitment in groups of wolves before and after harvest in Idaho, USA.Turnover of breeding females increased polygamy and potential recruits per group by providing breeding opportunities for subordinates although resultant group size was unaffected 1 year after the turnover. Breeder turnover had no effect on the number of nonbreeding helpers per group. After breeding male turnover, fewer female pups were recruited in the new males’ litters. Harvest had no effect on the frequency of breeder turnover.We found that breeder turnover led to shifts in the reproductive hierarchies within groups and the resulting changes to group composition were quite variable and depended on the sex of the breeder lost. We hypothesize that nonbreeding females direct help away from non-kin female pups to preserve future breeding opportunities for themselves. Breeder turnover had marked effects on the breeding opportunities of subordinates and the number and sex ratios of subsequent litters of pups. Seemingly subtle changes to groups, such as the loss of one individual, can greatly affect group composition, genetic content, and short-term population growth when the individual lost is a breeder.

Effects of breeder turnover and harvest on group composition and recruitment in a social carnivore.

PubMed

Ausband, David E; Mitchell, Michael S; Waits, Lisette P

2017-09-01

Breeder turnover can influence population growth in social carnivores through changes to group size, composition and recruitment. Studies that possess detailed group composition data that can provide insights about the effects of breeder turnover on groups have generally been conducted on species that are not subject to recurrent annual human harvest. We wanted to know how breeder turnover affects group composition and how harvest, in turn, affects breeder turnover in cooperatively breeding grey wolves (Canis lupus Linnaeus 1758). We used noninvasive genetic sampling at wolf rendezvous sites to construct pedigrees and estimate recruitment in groups of wolves before and after harvest in Idaho, USA. Turnover of breeding females increased polygamy and potential recruits per group by providing breeding opportunities for subordinates although resultant group size was unaffected 1 year after the turnover. Breeder turnover had no effect on the number of nonbreeding helpers per group. After breeding male turnover, fewer female pups were recruited in the new males' litters. Harvest had no effect on the frequency of breeder turnover. We found that breeder turnover led to shifts in the reproductive hierarchies within groups and the resulting changes to group composition were quite variable and depended on the sex of the breeder lost. We hypothesize that nonbreeding females direct help away from non-kin female pups to preserve future breeding opportunities for themselves. Breeder turnover had marked effects on the breeding opportunities of subordinates and the number and sex ratios of subsequent litters of pups. Seemingly subtle changes to groups, such as the loss of one individual, can greatly affect group composition, genetic content, and short-term population growth when the individual lost is a breeder. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Stable and solubilized active Au atom clusters for selective epoxidation of cis-cyclooctene with molecular oxygen

DOE PAGES

Qian, Linping; Wang, Zhen; Beletskiy, Evgeny V.; ...

2017-03-28

Here, the ability of Au catalysts to effect the challenging task of utilizing molecular oxygen for the selective epoxidation of cyclooctene is fascinating. Although supported nanometre-size Au particles are poorly active, here we show that solubilized atomic Au clusters, present in ng ml –1 concentrations and stabilized by ligands derived from the oxidized hydrocarbon products, are active. They can be formed from various Au sources. They generate initiators and propagators to trigger the onset of the auto-oxidation reaction with an apparent turnover frequency of 440 s –1, and continue to generate additional initiators throughout the auto-oxidation cycle without direct participationmore » in the cycle. Spectroscopic characterization suggests that 7–8 atom clusters are effective catalytically. Extension of work based on these understandings leads to the demonstration that these Au clusters are also effective in selective oxidation of cyclohexene, and that solubilized Pt clusters are also capable of generating initiators for cyclooctene epoxidation.« less

Stable and solubilized active Au atom clusters for selective epoxidation of cis-cyclooctene with molecular oxygen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Linping; Wang, Zhen; Beletskiy, Evgeny V.

Here, the ability of Au catalysts to effect the challenging task of utilizing molecular oxygen for the selective epoxidation of cyclooctene is fascinating. Although supported nanometre-size Au particles are poorly active, here we show that solubilized atomic Au clusters, present in ng ml –1 concentrations and stabilized by ligands derived from the oxidized hydrocarbon products, are active. They can be formed from various Au sources. They generate initiators and propagators to trigger the onset of the auto-oxidation reaction with an apparent turnover frequency of 440 s –1, and continue to generate additional initiators throughout the auto-oxidation cycle without direct participationmore » in the cycle. Spectroscopic characterization suggests that 7–8 atom clusters are effective catalytically. Extension of work based on these understandings leads to the demonstration that these Au clusters are also effective in selective oxidation of cyclohexene, and that solubilized Pt clusters are also capable of generating initiators for cyclooctene epoxidation.« less

OPTIMIZING MINIRHIZOTRON SAMPLE FREQUENCY FOR AN EVERGREEN AND DECIDIOUS TREE SPECIES

EPA Science Inventory

Increasingly minirhizotrons are being used in natural ecosystems to determine fine root production and turnover, as they provide a nondestructive, in situ method for studying fine root dynamics. Our objective is to determine how image collection frequency influences estimates of ...

How serious of a problem is staff turnover in substance abuse treatment? A longitudinal study of actual turnover.

PubMed

Eby, Lillian T; Burk, Hannah; Maher, Charleen P

2010-10-01

In the substance abuse treatment field, the annual turnover rate is cited as being anywhere between 19% and 50% (J.A. Johnson & P.M. Roman, 2002; S.L. Gallon, R.M. Gabriel, J.R.W. Knudsen, 2003; H.K. Knudsen, J.A. Johnson, & P.M. Roman, 2003; A.T. McLellan, D. Carise, & H.D. Kleber, 2003). However, no research to date has evaluated these claims by tracking turnover longitudinally using organizational turnover data from substance abuse treatment centers. This research presents the results of a longitudinal study designed to systematically examine actual turnover among counselors and clinical supervisors. Twenty-seven geographically dispersed treatment organizations, serving a wide range of clients in the public and private sector, provided data for the study over a 2-year time span (2008-2009). The annual turnover rate was 33.2% for counselors and 23.4% for clinical supervisors. For both groups, the majority of turnover was voluntary (employee-initiated). Specific reasons for turnover were largely consistent across the two groups, with the most common reason being a new job or new opportunity. The findings are discussed in terms of the unique employment context of substance abuse treatment. Practical recommendations are also discussed to help stem the tide of turnover in the field of substance abuse treatment. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Microbial carbon turnover in the plant-rhizosphere-soil continuum

NASA Astrophysics Data System (ADS)

Malik, Ashish; Dannert, Helena; Griffiths, Robert; Thomson, Bruce; Gleixner, Gerd

2014-05-01

Soil microbial biomass contributes significantly to maintenance of soil organic matter (SOM). It is well known that biochemical fractions of soil microorganisms have varying turnover and therefore contribute differentially to soil C storage. Here we compare the turnover rates of different microbial biochemical fractions using a pulse chase 13CO2 plant labelling experiment. The isotope signal was temporally traced into rhizosphere soil microorganisms using the following biomarkers: DNA, RNA, fatty acids and chloroform fumigation extraction derived microbial biomass size classes. C flow into soil microbial functional groups was assessed through phospholipid and neutral lipid fatty acid (PLFA/NLFA) analyses. Highest 13C enrichment was seen in the low molecular weight (LMW) size class of microbial biomass (Δδ13C =151) and in nucleic acids (DNA: 38o RNA: 66) immediately after the pulse followed by a sharp drop. The amount of 13C in the high molecular weight (HMW) microbial biomass (17-81) and total fatty acids (32-54) was lower initially and stayed relatively steady over the 4 weeks experimental period. We found significant differences in turnover rates of different microbial biochemical and size fractions. We infer that LMW cytosolic soluble compounds are rapidly metabolized and linked to respiratory C fluxes, whereas mid-sized products of microbial degradation and HMW polymeric compounds have lower renewal rate in that order. The turnover of cell wall fatty acids was also very slow. DNA and RNA showed faster turnover rate; and as expected RNA renewal was the fastest due to its rapid production by active microorganisms independent of cell replication. 13C incorporation into different functional groups confirmed that mutualistic arbuscular mycorrhizal fungi rely on root C and are important in the initial plant C flux. We substantiated through measurements of isotope incorporation into bacterial RNA that rhizosphere bacteria are also important in the initial C conduit from plants. Other saprophytic fungi and bacteria show a delayed 13C incorporation pattern which could suggest secondary 13C assimilation often indicative of trophic interactions. Thus, different soil microbial biochemical fractions as well as functional groups show differential C turnover which could have implications on soil C storage.

Arginine-Containing Ligands Enhance H-2 Oxidation Catalyst Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, Arnab; Roberts, John A.; Shaw, Wendy J.

2014-06-16

In H2 fuel cells, performance depends on factors controlling turnover frequency and energy efficiency in the electrocatalytic oxidation of H2. Nature uses the hydrogenase enzymes to oxidize H2 at high turnover frequencies (up to 20,000 s-1) and low overpotentials (<100 mV), while the fastest synthetic catalyst reported to date only oxidizes H2 at 50 s-1 under 1 atm H2. Here we report a water-soluble complex incorporating the amino acid arginine, [NiII(PCy2NArg2)2]6+, that operates at 210 s-1 (180 mV overpotential) under 1 atm H2 and 144,000 s-1 (460 mV overpotential) under 133 atm H2. The complex functions from pH 0-14 withmore » rates increasing at lower pH values. The arginine groups impart water solubility and play a critical role in enhancing turnover frequency, most consistent with an intramolecular Arg-Arg interaction that controls the structure of the catalyst active site. This work was funded by the Office of Science Early Career Research Program through the US DOE, BES (AD, WJS), and the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US DOE, BES (JASR). PNNL is operated by Battelle for the US DOE.« less

Oven controlled N++ [1 0 0] length-extensional mode silicon resonator with frequency stability of 1 ppm over industrial temperature range

NASA Astrophysics Data System (ADS)

You, Weilong; Pei, Binbin; Sun, Ke; Zhang, Lei; Yang, Heng; Li, Xinxin

2017-10-01

This paper presents an oven controlled N++ [1 0 0] length-extensional mode silicon resonator, with a lookup-table based control algorithm. The temperature coefficient of resonant frequency (TCF) of the N++ doped resonator is nonlinear, and there is a turnover temperature point at which the TCF is equal to zero. The resonator is maintained at the turnover point by Joule heating; this temperature is a little higher than the upper limit of the industrial temperature range. It is demonstrated that the control algorithm based on the thermoresistor on the substrate and the lookup table for heating voltage versus chip temperature is sufficiently accurate to achieve a frequency stability of  ±0.5 ppm over the industrial temperature range. Because only two leads are required for electrical heating and piezoresistive sensing, the power required for heating of this resonator can be potentially lower than that of the oscillators with closed-loop oven control algorithm. It is also shown that the phase noise can be suppressed at the turnover temperature because of the very low value of the TCF, which justifies the usage of the heating voltage as the excitation voltage of the Wheatstone half-bridge.

Heptanuclear CoII5CoIII2 Cluster as Efficient Water Oxidation Catalyst.

PubMed

Xu, Jia-Heng; Guo, Ling-Yu; Su, Hai-Feng; Gao, Xiang; Wu, Xiao-Fan; Wang, Wen-Guang; Tung, Chen-Ho; Sun, Di

2017-02-06

Inspired by the transition-metal-oxo cubical Mn 4 CaO 5 in photosystem II, we herein report a disc-like heptanuclear mixed-valent cobalt cluster, [Co II 5 Co III 2 (mdea) 4 (N 3 ) 2 (CH 3 CN) 6 (OH) 2 (H 2 O) 2 ·4ClO 4 ] (1, H 2 mdea = N-methyldiethanolamine), for photocatalytic oxygen evolution. The topology of the Co 7 core resembles a small piece of cobaltate protected by terminal H 2 O, N 3 - , CH 3 CN, and multidentate N-methyldiethanolamine at the periphery. Under the optimal photocatalytic conditions, 1 exhibits water oxidation activity with a turnover number (TON) of 210 and a turnover frequency (TOF initial ) of 0.23 s -1 . Importantly, electrospray mass spectrometry (ESI-MS) was used to not only identify the possible main active species in the water oxidation reaction but also monitor the evolutions of oxidation states of cobalt during the photocatalytic reactions. These results shed light on the design concept of new water oxidation catalysts and mechanism-related issues such as the key active intermediate and oxidation state evolution in the oxygen evolution process. The magnetic properties of 1 were also discussed in detail.

Skeletal Health After Continuation, Withdrawal, or Delay of Alendronate in Men With Prostate Cancer Undergoing Androgen-Deprivation Therapy

PubMed Central

Greenspan, Susan L.; Nelson, Joel B.; Trump, Donald L.; Wagner, Julie M.; Miller, Megan E.; Perera, Subashan; Resnick, Neil M.

2008-01-01

Purpose Androgen-deprivation therapy (ADT) for prostate cancer is associated with bone loss and osteoporotic fractures. Our objective was to examine changes in bone density and turnover with sustained, discontinued, or delayed oral bisphosphonate therapy in men receiving ADT. Patients and Methods A total of 112 men with nonmetastatic prostate cancer receiving ADT were randomly assigned to alendronate 70 mg once weekly or placebo in a double-blind, partial-crossover trial with a second random assignment at year 2 for those who initially received active therapy. Outcomes included bone mineral density and bone turnover markers. Results Men initially randomly assigned to alendronate and randomly reassigned at year 2 to continue had additional bone density gains at the spine (mean, 2.3% ± 0.7) and hip (mean, 1.3% ± 0.5%; both P < .01); those randomly assigned to placebo in year 2 maintained density at the spine and hip but lost (mean, −1.9% ± 0.6%; P < .01) at the forearm. Patients randomly assigned to begin alendronate in year 2 experienced improvements in bone mass at the spine and hip, but experienced less of an increase compared with those who initiated alendronate at baseline. Men receiving alendronate for 2 years experienced a mean 6.7% (± 1.2%) increase at the spine and a 3.2% (± 1.5%) at the hip (both P < .05). Bone turnover remained suppressed. Conclusion Among men with nonmetastatic prostate cancer receiving ADT, once-weekly alendronate improves bone density and decreases turnover. A second year of alendronate provides additional skeletal benefit, whereas discontinuation results in bone loss and increased bone turnover. Delay in bisphosphonate therapy appears detrimental to bone health. PMID:18802155

Home nurses' turnover intentions: the impact of informal supervisory feedback and self-efficacy.

PubMed

Van Waeyenberg, Thomas; Decramer, Adelien; Anseel, Frederik

2015-12-01

To examine how home nurses' turnover intentions are affected by the quality and frequency of supervisory feedback and by their own self-efficacy. Little is known about effective retention strategies for the growing home healthcare sector that struggles to retain an adequate workforce. While the work environment and supervisors have been found to play a key-role in nurses' turnover intentions, home nurses mostly work autonomously and apart from their supervisors. These circumstances require a customized approach and need to be understood to ensure high-quality home health care. We used a correlational, cross-sectional survey design. A convenience sample of 312 home nurses was selected from a division of a large home health care organization in Flanders, Belgium. Data were collected in 2013 using structured questionnaires and analysed using descriptive statistics, structural equation modelling and relative weight analysis. The quality of feedback was related to lower levels of turnover intentions. This relationship was fully mediated by home nurses' self-efficacy. Frequent favourable feedback was directly related to lower turnover intentions while the relationship between frequent unfavourable feedback and turnover intentions was conditional on home nurses' level of self-efficacy. This study contributes to our understanding of home nurses' turnover intentions and the role of informal supervisory feedback and home nurses' self-efficacy. © 2015 John Wiley & Sons Ltd.

Factors that contribute to public sector nurses’ turnover in Limpopo province of South Africa

PubMed Central

2013-01-01

Abstract Background The ongoing worldwide phenomenon of a shortage of about 4.3 million nurses and midwives poses a threat to health service delivery. Limpopo province had the worst nurse shortage of over 60% in 2010. Authors attribute this shortage to turnover of nurses. The quest to describe factors contributing to nurses’ turnover led to this study in Limpopo province, South Africa. Objectives To explore and describe factors that contribute to nurses’ turnover in Limpopo province of South Africa by assessing public sector nurses’ job satisfaction in relation to common determinants of job satisfaction. Method A descriptive cross-sectional approach used primary quantitative data collected from 141 of 380 respondents (31.1% response rate) contacted incidentally. Self-administered hand-delivered questionnaires were used to gather ordinal data, which were analysed in terms of frequency and percentage tables using the Statistical Package for Social Sciences version 6. The sum of positive and negative effects was used to determine satisfaction; if positive effects were greater than negative effects respondents were judged to be satisfied and vice versa. Results Frequency and percentage tables revealed that nurses in Limpopo province were more dissatisfied (53.9%) than satisfied (37.8%) with their jobs. Factors which respondents were found to be dissatisfied with included staffing (85.2%), availability of workplace resources (83.7%), salaries (78.8%), workplace safety (73.7%), career development opportunities (64.5%) and hours of work (47.6%). Conclusion Nurses’ turnover is attributed to nurses’ dissatisfaction with staffing, resources, salaries and workplace safety. Attention needs to be given to these specific issues if retention of nurses is to be achieved.

Turnover Begets Turnover: An Examination of Job and Occupational Instability among Child Care Center Staff.

ERIC Educational Resources Information Center

Whitebook, Marcy; Sakai, Laura

2003-01-01

Examined job/occupational instability among child care teachers and directors. Found that over half of teachers and a third of directors had left their centers 4 years after initial interviews. Highly trained teachers were more likely to leave jobs if they earned lower wages, worked in less stable climate, or worked with greater percentage of…

"Who Stays and Who Leaves?" Findings from a Three-Part Study of Teacher Turnover in NYC Middle Schools

ERIC Educational Resources Information Center

Marinell, William H.; Coca, Vanessa M.

2013-01-01

This paper synthesizes findings from the Research Alliance's investigation of teacher turnover in New York City's public middle schools. These years are widely recognized as a critical turning point for students, and the NYC Department of Education (DOE) is pursuing a range of middle school improvement initiatives. The stability of the middle…

Frequency of Principal Turnover in Ohio's Elementary Schools

ERIC Educational Resources Information Center

Partlow, Michelle Chaplin; Ridenour, Carolyn S.

2008-01-01

One remedy for Ohio schools that fail to meet the state's test score criteria for "effectiveness" is to force a change in the principalship. Concerns have been raised that such a remedy may simultaneously undermine the organizational stability of the school. The researchers in this study examined the frequency with which elementary…

Physics of compact nonthermal sources. III - Energetic considerations. [electron synchrotron radiation

NASA Technical Reports Server (NTRS)

Burbidge, G. R.; Jones, T. W.; Odell, S. L.

1974-01-01

The energy content of the compact incoherent electron-synchrotron sources 3C 84, 3C 120, 3C 273, 3C 279, 3C 454.3, CTA 102, 3C 446, PKS 2134+004, VRO 42.22.01 and OJ 287 is calculated on the assumption that the low-frequency turnovers in the radio spectrum are due to self-absorption and that the electron distribution is isotropic. The dependence of the source parameters on various modifications of the standard assumptions is determined. These involve relativistic motions, alternate explanations for the low-frequency turnover, proton-synchrotron radiation, and distance to the source. The canonical interpretation is found to be accurate in many respects; some of the difficulties and ways of dealing with them are discussed in detail.

Development of factors to convert frequency to rate for β-cell replication and apoptosis quantified by time-lapse video microscopy and immunohistochemistry

PubMed Central

Saisho, Yoshifumi; Manesso, Erica; Gurlo, Tatyana; Huang, Chang-jiang; Toffolo, Gianna M.; Cobelli, Claudio; Butler, Peter C.

2009-01-01

An obstacle to development of methods to quantify β-cell turnover from pancreas tissue is the lack of conversion factors for the frequency of β-cell replication or apoptosis detected by immunohistochemistry to rates of replication or apoptosis. We addressed this obstacle in islets from 1-mo-old rats by quantifying the relationship between the rate of β-cell replication observed directly by time-lapse video microscopy (TLVM) and the frequency of β-cell replication in the same islets detected by immunohistochemistry using antibodies against Ki67 and insulin in the same islets fixed immediately after TLVM. Similarly, we quantified the rate of β-cell apoptosis by TLVM and then the frequency of apoptosis in the same islets using TdT-mediated dUTP nick-end labeling and insulin. Conversion factors were developed by regression analysis. The conversion factor from Ki67 labeling frequency (%) to actual replication rate (%events/h) is 0.025 ± 0.003 h−1. The conversion factor from TdT-mediated dUTP nick-end labeling frequency (%) to actual apoptosis rate (%events/h) is 0.41 ± 0.05 h−1. These conversion factors will permit development of models to evaluate β-cell turnover in fixed pancreas tissue. PMID:18940937

Turnover intention among hospital-based registered nurses in the Eastern Caribbean.

PubMed

Lansiquot, Beverley Anne; Tullai-McGuinness, Susan; Madigan, Elizabeth

2012-06-01

Vacancy rates for nurses in the English-speaking Caribbean are estimated at 30% with turnover typically associated with migration. The purpose of this study was to describe the characteristics of hospital-based registered nurses (RNs) in the sub-region, their practice environment and turnover intention in two and five years, respectively, and to determine the relationships among practice environment characteristics and turnover intention. A descriptive correlational design was used with self-reported questionnaires from a convenience sample of 301 RNs working in hospitals in four English speaking Eastern Caribbean countries. Single-item visual analog scales (VAS) were used to measure turnover intention in 2 years and 5 years. The Practice Environment Scale of the Nursing Work Index (PES-NWI) measured the characteristics in the practice environment. The mean age of the nurses was 32.5 (SD = 6.75) years. Most nurses (58.8%) were single and 91.4% had relatives living abroad. Nurses scored three PES-NWI subscales < 2.5, indicating a less positive practice environment: resource adequacy, nurse participation in hospital affairs, and nurse managers' ability, leadership, and support. The subscale for collegial nurse-physician relations received the best rating (mean = 2.61, SD = .62). For 2-year intention to leave, the mean rating on the 100-mm VAS was 63.2, while that for the 5-year intention to leave was 65.6. No significant correlations were found among four of the five PES-NWI subscales and turnover intention in 2 and 5 years. The practice environment, while generally unfavorable, is not associated with the nurses' intention to leave their jobs. These findings support the current policy position that calls for managing turnover among nurses. Nursing and health system administrators should assess, plan, and implement workforce policies to slow the outflow of nurses. Initiatives to improve the work environment and the delivery of high-quality care are important to RNs in the Eastern Caribbean. Managing the negative impact of continuous outflow of nurses through turnover requires long-term coordinated policy and human resource development and management initiatives to sustain the supply of RNs in the subregion. © 2012 Sigma Theta Tau International.

An application of Six Sigma methodology to turnover intentions in health care.

PubMed

Taner, Mehmet

2009-01-01

The purpose of this study is to show how the principles of Six Sigma can be applied to the high turnover problem of doctors in medical emergency services and paramedic backup. Six Sigma's define-measure-analyse-improve-control (DMAIC) is applied for reducing the turnover rate of doctors in an organisation operating in emergency services. Variables of the model are determined. Explanatory factor analysis, multiple regression, analysis of variance (ANOVA) and Gage R&R are employed for the analysis. Personal burnout/stress and dissatisfaction from salary were found to be the "vital few" variables. The organisation took a new approach by improving its initiatives to doctors' working conditions. Sigma level of the process is increased. New policy and process changes have been found to effectively decrease the incidence of turnover intentions. The improved process is gained, standardised and institutionalised. This study is one of the few papers in the literature that elaborates the turnover problem of doctors working in the emergency and paramedic backup services.

Implementation of an Initial Training Program for New Employees in a Profoundly Mentally and Physically Handicapped Children and Adult Residential Facility.

ERIC Educational Resources Information Center

Hoeft, Linda A.

A project was designed to reduce the turnover of direct care staff in a community-based residential facility that provides a home and educational or adult day training services for 54 severely or profoundly mentally and physically handicapped children and adults. The project sought to reduce total staff turnover by 40%, reduce employee…

A Quantitative Spatial Proteomics Analysis of Proteome Turnover in Human Cells*

PubMed Central

Boisvert, François-Michel; Ahmad, Yasmeen; Gierliński, Marek; Charrière, Fabien; Lamont, Douglas; Scott, Michelle; Barton, Geoff; Lamond, Angus I.

2012-01-01

Measuring the properties of endogenous cell proteins, such as expression level, subcellular localization, and turnover rates, on a whole proteome level remains a major challenge in the postgenome era. Quantitative methods for measuring mRNA expression do not reliably predict corresponding protein levels and provide little or no information on other protein properties. Here we describe a combined pulse-labeling, spatial proteomics and data analysis strategy to characterize the expression, localization, synthesis, degradation, and turnover rates of endogenously expressed, untagged human proteins in different subcellular compartments. Using quantitative mass spectrometry and stable isotope labeling with amino acids in cell culture, a total of 80,098 peptides from 8,041 HeLa proteins were quantified, and their spatial distribution between the cytoplasm, nucleus and nucleolus determined and visualized using specialized software tools developed in PepTracker. Using information from ion intensities and rates of change in isotope ratios, protein abundance levels and protein synthesis, degradation and turnover rates were calculated for the whole cell and for the respective cytoplasmic, nuclear, and nucleolar compartments. Expression levels of endogenous HeLa proteins varied by up to seven orders of magnitude. The average turnover rate for HeLa proteins was ∼20 h. Turnover rate did not correlate with either molecular weight or net charge, but did correlate with abundance, with highly abundant proteins showing longer than average half-lives. Fast turnover proteins had overall a higher frequency of PEST motifs than slow turnover proteins but no general correlation was observed between amino or carboxyl terminal amino acid identities and turnover rates. A subset of proteins was identified that exist in pools with different turnover rates depending on their subcellular localization. This strongly correlated with subunits of large, multiprotein complexes, suggesting a general mechanism whereby their assembly is controlled in a different subcellular location to their main site of function. PMID:21937730

Precise Stabilization of the Optical Frequency of WGMRs

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Matsko, Andrey; Matsko, Andrey; Yu, Nan; Maleki, Lute; Iltchenko, Vladimir

2009-01-01

Crystalline whispering gallery mode resonators (CWGMRs) made of crystals with axial symmetry have ordinary and extraordinary families of optical modes. These modes have substantially different thermo-refractive constants. This results in a very sharp dependence of differential detuning of optical frequency on effective temperature. This frequency difference compared with clock gives an error signal for precise compensation of the random fluctuations of optical frequency. Certain crystals, like MgF2, have turnover points where the thermo-refractive effect is completely nullified. An advantage for applications using WGMRs for frequency stabilization is in the possibility of manufacturing resonators out of practically any optically transparent crystal. It is known that there are crystals with negative and zero thermal expansion at some specific temperatures. Doping changes properties of the crystals and it is possible to create an optically transparent crystal with zero thermal expansion at room temperature. With this innovation s stabilization technique, the resultant WGMR will have absolute frequency stability The expansion of the resonator s body can be completely compensated for by nonlinear elements. This results in compensation of linear thermal expansion (see figure). In three-mode, the MgF2 resonator, if tuned at the turnover thermal point, can compensate for all types of random thermal-related frequency drift. Simplified dual-mode method is also available. This creates miniature optical resonators with good short- and long-term stability for passive secondary frequency ethalon and an active resonator for active secondary frequency standard (a narrowband laser with long-term stability).

Influence of synchrotron self-absorption on 21-cm experiments

NASA Astrophysics Data System (ADS)

Zheng, Qian; Wu, Xiang-Ping; Gu, Jun-Hua; Wang, Jingying; Xu, Haiguang

2012-08-01

The presence of spectral curvature resulting from the synchrotron self-absorption of extragalactic radio sources could break down the spectral smoothness feature. This leads to the premise that the bright radio foreground can be successfully removed in 21-cm experiments that search for the epoch of reionization (EoR). We present a quantitative estimate of the effect of the spectral curvature resulting from the synchrotron self-absorption of extragalactic radio sources on the measurement of the angular power spectrum of the low-frequency sky. We incorporate a phenomenological model, which is characterized by the fraction (f) of radio sources with turnover frequencies in the range of 100-1000 MHz and by a broken power law for the spectral transition around the turnover frequencies νm, into simulated radio sources over a small sky area of 10° × 10°. We compare statistically the changes in their residual maps with and without the inclusion of the synchrotron self-absorption of extragalactic radio sources after the bright sources of S150 MHz ≥100 mJy are excised. Furthermore, the best-fitting polynomials in the frequency domain on each pixel are subtracted. It has been shown that the effect of synchrotron self-absorption on the detection of the EoR depends sensitively on the spectral profiles of the radio sources around the turnover frequencies νm. A hard transition model, described by the broken power law with the turnover of spectral index at νm, would leave pronounced imprints on the residual background and would therefore cause serious confusion with the cosmic EoR signal. However, the spectral signatures on the angular power spectrum of the extragalactic foreground, generated by a soft transition model in which the rising and falling power laws of the spectral distribution around νm are connected through a smooth transition spanning ≥200 MHz in a characteristic width, can be fitted and consequently subtracted by the use of polynomials to an acceptable degree (δT < 1 mK). As this latter scenario seems to be favoured in both theoretical expectations and radio spectral observations, we conclude that the contamination of extragalactic radio sources by synchrotron self-absorption in 21-cm experiments is probably very minor.

SPECIES AND ROTATION FREQUENCY INFLUENCE SOIL NITROGEN IN SIMPLIFIED TROPICAL PLANT COMMUNITIES

Treesearch

JOHN J. EWEL

2006-01-01

Among the many factors that potentially influence the rate at which nitrogen (N) becomes available to plants in terrestrial ecosystems are the identity and diversity of species composition, frequency of disturbance or stand turnover, and time. Replicated suites of investigator-designed communities afforded an opportunity to examine the effects of those factors on net N...

Nurse turnover: a literature review - an update.

PubMed

Hayes, Laureen J; O'Brien-Pallas, Linda; Duffield, Christine; Shamian, Judith; Buchan, James; Hughes, Frances; Laschinger, Heather K Spence; North, Nicola

2012-07-01

Concerns related to the complex issue of nursing turnover continue to challenge healthcare leaders in every sector of health care. Voluntary nurse turnover is shown to be influenced by a myriad of inter-related factors, and there is increasing evidence of its negative effects on nurses, patients and health care organizations. The objectives were to conduct a comprehensive review of the related literature to examine recent findings related to the issue of nursing turnover and its causes and consequences, and to identify on methodological challenges and the implications of new evidence for future studies. A comprehensive search of the recent literature related to nursing turnover was undertaken to summarize findings published in the past six years. Electronic databases: MEDLINE, CINAHL and PubMed, reference lists of journal publications. Keyword searches were conducted for publications published 2006 or later that examined turnover or turnover intention in employee populations of registered or practical/enrolled or assistant nurses working in the hospital, long-term or community care areas. Literature findings are presented using an integrative approach and a table format to report individual studies. From about 330 citations or abstracts that were initially scanned for content relevance, 68 studies were included in this summary review. The predominance of studies continues to focus on determinants of nurse turnover in acute care settings. Recent studies offer insight into generational factors that should be considered in strategies to promote stable staffing in healthcare organizations. Nursing turnover continues to present serious challenges at all levels of health care. Longitudinal research is needed to produce new evidence of the relationships between nurse turnover and related costs, and the impact on patients and the health care team. Copyright © 2011 Elsevier Ltd. All rights reserved.

Soil clay content controls the turnover of slow soil carbon across Chinese cropland

NASA Astrophysics Data System (ADS)

Feng, W.; Jiang, J.; Li, J.

2017-12-01

Improving the prediction of changes in global soil organic carbon (SOC) lies in accurate estimate of C inputs to soils and SOC turnover time. Since C inputs to soils in cropland can be estimated due to well documented data of crop yields, SOC turnover rate becomes critical for accurate prediction of changes in SOC. The laboratory incubation is widely used but cannot well represent the turnover of slow soil C that accounts for the majority of total SOC, while the long-term observation of temporal changes in SOC stock offers an opportunity to estimate the turnover of slow soil C. Using time series data of SOC stock of twenty long-term agricultural trials that have initiated since 1990 in China, we estimated SOC turnover rates based on changes in soil C pool size and aimed to identify the dominant controls on SOC turnover rate across Chinese cropland. We used the two-pool first-order kinetic soil C model and the inverse modeling with Markov chain the Monte Carlo algorithm, and estimated humification coefficient (h) of C inputs to soils, turnover rates of fast and slow soil C pools, and the transfer coefficient between these two soil C pools. The preliminary results show that the turnover rate of slow soil C is positively correlated with climate (i.e. mean annual temperature and precipitation) but negatively correlated with the clay content, demonstrating that the clay content is important in regulating SOC turnover rates. The ratio of humification coefficient to C turnover rate (h/k) that indicates soil C sequestration efficiency, is negatively correlated with climate and positively correlated with the clay content. In addition, the quantity of C inputs is correlated with h/k and the turnover rate of slow soil C, suggesting that the quantity of C inputs plays an important role in mediating C sequestration efficiency. Further results will inform us the main controls on SOC turnover in Chinese cropland. Keywords: SOC; turnover; long-term trial; temporal change; clay content; inverse modeling

Nurse turnover in substance abuse treatment programs affiliated with the National Drug Abuse Treatment Clinical Trials Network.

PubMed

Knudsen, Hannah K; Abraham, Amanda J; Roman, Paul M; Studts, Jamie L

2011-04-01

Voluntary nurse turnover, which is costly and disrupts patient care, has not been studied as an organizational phenomenon within substance abuse treatment organizations. In this exploratory study, we examined the frequency and correlates of nurse turnover within treatment programs affiliated with the National Drug Abuse Treatment Clinical Trials Network. During face-to-face interviews conducted in 2005-2006, 215 program administrators reported the number of nurses currently employed. Leaders of programs with nursing staff then described the number of nurses who had voluntarily quit in the past year, the degree to which filling vacant nursing positions was difficult, and the average number of days to fill a vacant position. About two thirds of these programs had at least one nurse on staff. In programs with nurses, the average rate of voluntary turnover was 15.0%. Turnover was significantly lower in hospital-based programs and programs offering adolescent treatment but higher in facilities offering residential treatment. Most of the administrators indicated that filling vacant nurse positions was difficult and took more than 2 months to complete. These findings suggest that nurse turnover is a significant issue facing many substance abuse treatment facilities. Efforts to improve retention of the addiction treatment workforce should be expanded to include nursing professionals. Copyright © 2011 Elsevier Inc. All rights reserved.

Initial turnover rates of two standard wood substrates following land-use change in subalpine ecosystems in the Swiss Alps

Treesearch

Anita C. Risch; Martin F. Jurgensen; Deborah S. Page-Dumroese; Martin Schutz

2013-01-01

Forest cover has increased in mountainous areas of Europe over the past decades because of the abandonment of agricultural areas (land-use change). For this reason, understanding how land-use change affects carbon (C) source-sink strength is of great importance. However, most studies have assessed mountainous systems C stocks, and less is known about C turnover rates,...

Measure Guideline. Five Steps to Implement the Public Housing Authority Energy-Efficient Unit Turnover Checklist

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liaukus, Christine

2015-07-09

Five Steps to Implementing the PHA Energy Efficient Unit Turnover Package (ARIES, 2014) is a guide to prepare for the installation of energy efficient measures during a typical public housing authority unit turnover. While a PHA is cleaning, painting and readying a unit for a new resident, there is an opportunity to incorporate energy efficiency measures to further improve the unit's performance. The measures on the list are simple enough to be implemented by in-house maintenance personnel, inexpensive enough to be folded into operating expenses without needing capital budget, and fast enough to implement without substantially changing the number ofmore » days between occupancies, a critical factor for organizations where the demand for dwelling units far outweighs the supply. The following guide lays out a five step plan to implement the EE Unit Turnover Package in your PHA, from an initial Self-Assessment through to Package Implementation.« less

The impact of nurse turnover on patient, nurse, and system outcomes: a pilot study and focus for a multicenter international study.

PubMed

O'Brien-Pallas, Linda; Griffin, Pat; Shamian, Judith; Buchan, James; Duffield, Christine; Hughes, Frances; Spence Laschinger, Heather K; North, Nicola; Stone, Patricia W

2006-08-01

Research about the economic impact of nurse turnover has been compromised by a lack of consistent definitions and measurement. This article describes a study that was designed to refine a methodology to examine the costs associated with nurse turnover. Nursing unit managers responded to a survey that contained items relating to budgeted full-time equivalents, new hires, and turnover, as well as direct and indirect costs. The highest mean direct cost was incurred through temporary replacements, whereas the highest indirect cost was decreased initial productivity of the new hire. The study allowed the identification of the availability of data and where further refinement of data definition of variables is needed. The results provided significant evidence to justify increased emphasis on nurse retention strategies and the creation of healthy work environments for nurses.

Numerical simulation of the generation of turbulence from cometary ion pick-up

NASA Technical Reports Server (NTRS)

Goldstein, M. L.; Roberts, D. A.; Matthaeus, W. H.

1987-01-01

Observations of magnetic field fluctuations near Comet Halley have revealed a rapid development of a Kolmogoroff-like turbulence spectrum extending from below 0.01 Hz to above 0.1 Hz. Spectra obtained far from the comet have a strong peak in power near the Doppler-shifted ion-cyclotron frequency of singly ionized water. Closer to the comet, the spectrum at higher frequencies is enhanced in power level over the background solar wind spectrum by approximately an order of magnitude. The equations of incompressible MHD are solved using a two-dimensional 256 x 256 mode spectral method code to simulate this spectral evolution as an inertial range turbulent cascade. The initial conditions contained a constant magnetic field and a single coherent wave mode at a low wave number. The solar wind turbulence was modeled by a background noise spectrum having a Kolmogoroff spectral index. The coherent mode decayed into an inertial range spectrum with Kolmogoroff slope within a few eddy-turnover times. Both the time scale and the increase in power level of the turbulence seen in the simulation are in accord with the Giotto observations.

Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

PubMed Central

Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

2015-01-01

Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

Alcohol Oxidation at Platinum–Gas and Platinum–Liquid Interfaces: The Effect of Platinum Nanoparticle Size, Water Coadsorption, and Alcohol Concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatsumi, Hironori; Liu, Fudong; Han, Hui-Ling

Platinum nanoparticles size range from 1 to 8 nm deposited on mesoporous silica MCF-17 catalyzed alcohol oxidations were studied in the gas and liquid phases. Among methanol, ethanol, 2- propanol and 2-butanol reactions, the turnover frequency increased with Pt nanoparticle size for all the alcohols utilized. The activation energies for the oxidations were almost same among all alcohol species, but higher in the gas phase than those in the liquid phase. Water coadsorption poisoned the reaction in the gas phase, while it increased the reaction turnover rates in the liquid phase. Sum frequency generation (SFG) vibrational spectroscopy studies and DFTmore » calculations revealed that the alcohol molecules pack horizontally on the metal surface in low concentrations and stand up in high concentrations, which affect the dissociation of β-hydrogen of the alcohols as the critical step in alcohol oxidations.« less

Alcohol Oxidation at Platinum–Gas and Platinum–Liquid Interfaces: The Effect of Platinum Nanoparticle Size, Water Coadsorption, and Alcohol Concentration

DOE PAGES

Tatsumi, Hironori; Liu, Fudong; Han, Hui-Ling; ...

2017-03-21

Platinum nanoparticles size range from 1 to 8 nm deposited on mesoporous silica MCF-17 catalyzed alcohol oxidations were studied in the gas and liquid phases. Among methanol, ethanol, 2- propanol and 2-butanol reactions, the turnover frequency increased with Pt nanoparticle size for all the alcohols utilized. The activation energies for the oxidations were almost same among all alcohol species, but higher in the gas phase than those in the liquid phase. Water coadsorption poisoned the reaction in the gas phase, while it increased the reaction turnover rates in the liquid phase. Sum frequency generation (SFG) vibrational spectroscopy studies and DFTmore » calculations revealed that the alcohol molecules pack horizontally on the metal surface in low concentrations and stand up in high concentrations, which affect the dissociation of β-hydrogen of the alcohols as the critical step in alcohol oxidations.« less

Faunal turnover in Neogene to Recent Caribbean reef corals and region environmental change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budd, A.F.; Johnson, K.G.; Stemann, T.A.

1993-03-01

Quantitative analyses of species richness and species extinction and origination rates in the Neogene to Recent Caribbean reef coral fauna show that a major episode of turnover occurred during middle to late Pliocene time (4--1 Ma). The data for the authors analyses consist of a new compilation of occurrences of 175 species and 49 genera in reef sequences in the Dominican Republic and Costa Rica and in 21 scattered sites ranging in age from 22 Ma to present. The results show that: (1) during turnover, more than 75% of all species living between 6--4 Ma (n = 82) became extinct;more » (2) during turnover, extinction and origination rates were equally and simultaneously high, and a relatively constant number of species was maintained in the fauna; (3) the taxonomic composition of Caribbean reefs remained relatively constant before (10--4 Ma) and after (1--0 Ma) turnover. Turnover therefore preceded the high frequency sea level oscillations of late Pleistocene time, and appears related to long-term, unidirectional changes in climate and/or ocean circulation across the Caribbean region in association with closure of the Isthmus of Panama. The observed correspondence between high origination and extinction rates indicates that the same environmental factors may have been associated with increases in both rates, and that local habitat differentiation and fragmentation may have been involved. Stability persisted in the region despite the severe environmental stresses associated with Pleistocene climate change.« less

Measuring milk intake in breast-fed babies.

PubMed

Coward, W A

1984-03-01

The relative merits of test weighing, water turnover methods, and a flowmeter method for the measurement of milk intake in breast-fed babies are reviewed to allow the prospective investigator to choose the method most suited to his or her needs. Provided that measurements are made over 3-4 days to minimize the effects of day-to-day variation in milk intake, test weighing is a satisfactory procedure when feed frequency is low and individual feed volumes are large. However, in developing countries where frequency is high and feed volumes low, test weighing is inherently less accurate and may impose an unfamiliar and unphysiological discipline on the mother and child that severely limits its usefulness. In these circumstances methods based on the measurement of water turnover rates using 2H2O are the only procedures likely to yield useful information. A method in which single doses of 2H2O are given to the mother, and milk intake rates measured over 14 days, is described. Neither test weighing nor water turnover methods provide simultaneous milk intake and composition data. The development of flowmeter methods will make this possible, but their use is likely to limited to metabolic wards rather than the home and widespread use in community studies is not a practical proposition.

Live-cell analysis of endogenous GFP-RPB1 uncovers rapid turnover of initiating and promoter-paused RNA Polymerase II.

PubMed

Steurer, Barbara; Janssens, Roel C; Geverts, Bart; Geijer, Marit E; Wienholz, Franziska; Theil, Arjan F; Chang, Jiang; Dealy, Shannon; Pothof, Joris; van Cappellen, Wiggert A; Houtsmuller, Adriaan B; Marteijn, Jurgen A

2018-05-08

Initiation and promoter-proximal pausing are key regulatory steps of RNA Polymerase II (Pol II) transcription. To study the in vivo dynamics of endogenous Pol II during these steps, we generated fully functional GFP-RPB1 knockin cells. GFP-RPB1 photobleaching combined with computational modeling revealed four kinetically distinct Pol II fractions and showed that on average 7% of Pol II are freely diffusing, while 10% are chromatin-bound for 2.4 seconds during initiation, and 23% are promoter-paused for only 42 seconds. This unexpectedly high turnover of Pol II at promoters is most likely caused by premature termination of initiating and promoter-paused Pol II and is in sharp contrast to the 23 minutes that elongating Pol II resides on chromatin. Our live-cell-imaging approach provides insights into Pol II dynamics and suggests that the continuous release and reinitiation of promoter-bound Pol II is an important component of transcriptional regulation. Copyright © 2018 the Author(s). Published by PNAS.

Data-model integration to interpret connectivity between biogeochemical cycling, and vegetation phenology and productivity in mountainous ecosystems under changing hydrologic regimes

NASA Astrophysics Data System (ADS)

Brodie, E.; Arora, B.; Beller, H. R.; Bill, M.; Bouskill, N.; Chakraborty, R.; Conrad, M. E.; Dafflon, B.; Enquist, B. J.; Falco, N.; Henderson, A.; Karaoz, U.; Polussa, A.; Sorensen, P.; Steltzer, H.; Wainwright, H. M.; Wang, S.; Williams, K. H.; Wilmer, C.; Wu, Y.

2017-12-01

In mountainous systems, snow-melt is associated with a large pulse of nutrients that originates from under-snow microbial mineralization of organic matter and microbial biomass turnover. Vegetation phenology in these systems is regulated by environmental cues such as air temperature ranges and photoperiod, such that, under typical conditions, vegetation greening and nutrient uptake occur in sync with microbial biomass turnover and nutrient release, closing nutrient cycles and enhancing nutrient retention. However, early snow-melt has been observed with increasing frequency in the mountainous west and is hypothesized to disrupt coupled plant-microbial behavior, potentially resulting in a temporal discontinuity between microbial nutrient release and vegetation greening. As part of the Watershed Function Scientific Focus Area (SFA) at Berkeley Lab we are quantifying below-ground biogeochemistry and above-ground phenology and vegetation chemistry and their relationships to hydrologic events at a lower montane hillslope in the East River catchment, Crested Butte, CO. This presentation will focus on data-model integration to interpret connectivity between biogeochemical cycling of nitrogen and vegetation nitrogen demand. Initial model results suggest that early snow-melt will result in an earlier accumulation and leaching loss of nitrate from the upper soil depths but that vegetation productivity may not decline as traits such as greater rooting depth and resource allocation to stems are favored.

The spectral energy distribution of powerful starburst galaxies - I. Modelling the radio continuum

NASA Astrophysics Data System (ADS)

Galvin, T. J.; Seymour, N.; Marvil, J.; Filipović, M. D.; Tothill, N. F. H.; McDermid, R. M.; Hurley-Walker, N.; Hancock, P. J.; Callingham, J. R.; Cook, R. H.; Norris, R. P.; Bell, M. E.; Dwarakanath, K. S.; For, B.; Gaensler, B. M.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Lenc, E.; McKinley, B.; Morgan, J.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q.

2018-02-01

We have acquired radio-continuum data between 70 MHz and 48 GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067 < z < 0.227) with the aim of separating synchrotron and free-free emission components. Using a Bayesian framework, we find the radio continuum is rarely characterized well by a single power law, instead often exhibiting low-frequency turnovers below 500 MHz, steepening at mid to high frequencies, and a flattening at high frequencies where free-free emission begins to dominate over the synchrotron emission. These higher order curvature components may be attributed to free-free absorption across multiple regions of star formation with varying optical depths. The decomposed synchrotron and free-free emission components in our sample of galaxies form strong correlations with the total-infrared bolometric luminosities. Finally, we find that without accounting for free-free absorption with turnovers between 90 and 500 MHz the radio continuum at low frequency (ν < 200 MHz) could be overestimated by upwards of a factor of 12 if a simple power-law extrapolation is used from higher frequencies. The mean synchrotron spectral index of our sample is constrained to be α = -1.06, which is steeper than the canonical value of -0.8 for normal galaxies. We suggest this may be caused by an intrinsically steeper cosmic ray distribution.

Assessing the effect of dietary calcium intake and 25 OHD status on bone turnover in women in Pakistan.

PubMed

Khan, Aysha Habib; Naureen, Ghazala; Iqbal, Romaina; Dar, Farhan Javed

2013-01-01

Bone health assessed in three towns of Karachi, Pakistan in females showed poor calcium intake, vitamin D deficiency, secondary hyperparathyroidism, and high bone turnover. Correlates of high bone turnover included females residing in Saddar Town, underweight females less than 30 years of age from low socio-economic status, and secondary hyperparathyroidism. To assess bone health and association of dietary calcium and 25 hydroxy vitamin D with bone turnover in the community-dwelling females of Karachi. Bone health was assessed in three randomly selected towns of Karachi, Pakistan. One premenopausal female fulfilling the inclusion criteria from each household was included in the study. Dietary calcium was assessed through a food frequency questionnaire and biochemical markers including calcium, phosphates, albumin, magnesium, creatinine, and SGPT, intact parathyroid hormone, 25 hydroxy vitamin D, and N-telopeptide of type I collagen were measured to assess the bone health. Three hundred and five females were included from three towns. Overall, 90.5% of females had vitamin D deficiency with 42.6 and 23.3% having secondary hyperparathyroidism and high bone turn over respectively. Prevalence of vitamin D deficiency, secondary hyperparathyroidism, and high bone turnover was significantly different among towns. Mean vitamin D levels were significantly low and iPTH levels significantly high in females with high bone turnover. Calcium intake was not significantly different among females with normal, high, and low bone turnover. Correlates of high bone turnover included females residing in Saddar Town, underweight females less than 30 years of age belonging to low socio-economic status, and secondary hyperparathyroidism. Compromised bone health is seen in community-dwelling females of Karachi. There is a need to perform large-scale community-based studies in all age groups to understand the interplay of markers in our population to understand the impact of these variables translating into the risk of osteoporosis.

Importance of charcoal in determining the age and chemistry of organic carbon in surface soils

NASA Astrophysics Data System (ADS)

Krull, Evelyn S.; Swanston, Christopher W.; Skjemstad, Jan O.; McGowan, Janine A.

2006-12-01

Understanding the chemical character and turnover time of the oldest soil organic carbon (SOC) fraction is fundamental in deciphering soil carbon sequestration processes and the fate of soil-eroded carbon in aquatic sediments. Two main processes are thought to extend the turnover time of SOC: protection by the mineral matrix and chemical recalcitrance. Various oxidation methods have been proposed to isolate the oldest and most recalcitrant SOC fraction, which is often assumed to be black carbon (BC). However, few data have been published that confirm the chemical character of the isolated fractions. Using established and newly developed methods together with 13C-NMR spectroscopy and AMS dating, we show that protection by the mineral matrix prolonged the turnover time of SOC by tens of years, but long-term (hundreds of years) stabilization was controlled by the inherent recalcitrance of SOC, determined by the type of ecosystems. In ecosystem without significant fire occurrences, the older SOC pool was comparably small and was represented by alkyl carbon. In ecosystems with high fire frequency charcoal constituted the oldest SOC pool, and constituted up to 35% of the total SOC. By applying methods with different oxidative strengths, it was possible to isolate different age groups of charcoal with different degrees of weathering. Further substantiation of this finding could provide a much greater resolution of paleo-fire events. Our results demonstrate that fire frequency plays a dominant role in determining the chemical nature and 14C abundance of SOC and that the separation of age groups of charcoal provides a means to reconstruct detailed fire histories. Our results indicate that modeling SOC turnover, transport and sequestration for frequently burnt environments requires modification of existing models, specifying an input and decay function for the charcoal pool in different environments.

Specific Cx43 phosphorylation events regulate gap junction turnover in vivo

PubMed Central

Solan, Joell L.; Lampe, Paul D.

2014-01-01

Gap junctions, composed of proteins from the connexin gene family, are highly dynamic structures that are regulated by kinase-mediated signaling pathways and interactions with other proteins. Phosphorylation of Connexin43 (Cx43) at different sites controls gap junction assembly, gap junction size and gap junction turnover. Here we present a model describing how Akt, mitogen activated protein kinase (MAPK) and src kinase coordinate to regulate rapid turnover of gap junctions. Specifically, Akt phosphorylates Cx43 at S373 eliminating interaction with zona occludens-1 (ZO-1) allowing gap junctions to enlarge. Then MAPK and src phosphorylate Cx43 to initiate turnover. We integrate published data with new data to test and refine this model. Finally, we propose that differential coordination of kinase activation and Cx43 phosphorylation controls the specific routes of disassembly, e.g., annular junction formation or gap junctions can potentially “unzip” and be internalized/endocytosed into the cell that produced each connexin. PMID:24508467

Health care workplace discrimination and physician turnover.

PubMed

Nunez-Smith, Marcella; Pilgrim, Nanlesta; Wynia, Matthew; Desai, Mayur M; Bright, Cedric; Krumholz, Harlan M; Bradley, Elizabeth H

2009-12-01

To examine the association between physician race/ ethnicity, workplace discrimination, and physician job turnover. Cross-sectional, national survey conducted in 2006-2007 of practicing physicians (n = 529) randomly identified via the American Medical Association Masterfile and the National Medical Association membership roster. We assessed the relationships between career racial/ethnic discrimination at work and several career-related dependent variables, including 2 measures of physician turnover, career satisfaction, and contemplation of career change. We used standard frequency analyses, odds ratios and chi2 statistics, and multivariate logistic regression modeling to evaluate these associations. Physicians who self-identified as nonmajority were significantly more likely to have left at least 1 job because of workplace discrimination (black, 29%; Asian, 24%; other race, 21%; Hispanic/Latino, 20%; white, 9%). In multivariate models, having experienced racial/ethnic discrimination at work was associated with high job turnover (adjusted odds ratio, 2.7; 95% CI, 1.4-4.9). Among physicians who experienced workplace discrimination, only 45% of physicians were satisfied with their careers (vs 88% among those who had not experienced workplace discrimination, p value < .01), and 40% were contemplating a career change (vs 10% among those who had not experienced workplace discrimination, p value < .001). Workplace discrimination is associated with physician job turnover, career dissatisfaction, and contemplation of career change. These findings underscore the importance of monitoring for workplace discrimination and responding when opportunities for intervention and retention still exist.

Further examination of predictors of turnover intention among mental health professionals.

PubMed

Yanchus, N J; Periard, D; Osatuke, K

2017-02-01

WHAT IS KNOWN ON THE SUBJECT?: When mental health professionals leave organizations, detrimental effects on quality of patient care occur. Reasons for leaving include incivility, lack of autonomy, perceptions of unfair treatment and feeling psychologically unsafe at work. This paper sought to investigate additional reasons why mental health professionals intend to quit or to cognitively withdraw from their jobs. WHAT DOES THIS PAPER ADD TO EXISTING KNOWLEDGE?: Past research on this topic is limited in its scope and data. Mainly fragmented evidence is available about predictors of job satisfaction and turnover intention (i.e. different mental health occupations examined in separate studies). Only two existing studies that examined broader mental health provider groups were limited by including few workforce settings, small sample sizes and insufficiently rigorous statistical analyses. We examined four occupations (mental health nurses, social workers, psychologists and psychiatrists), each represented through a large sample in multiple settings, all within one large healthcare network with complex patients. Our contribution is finding additional predictors (supervisory support, emotional exhaustion) of job satisfaction/turnover intention. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Organizations can consider using culture change initiatives to increase civility at work; this includes leadership support and role modelling of workplace behaviours. Leaders should monitor staffing levels and high workloads to pre-empt emotional exhaustion, which predicts turnover. Hiring and training supervisors should involve not only technical expertise, but also 'soft skills' necessary for creating civil and supportive work environments. Leaders and managers should use employee feedback data (e.g. organizational surveys) to learn about the workplace environments, and address areas of employees' concern. Introduction Given the global shortage of mental health professionals, high turnover rates within this workforce are concerning. We used United States of America Veterans Health Administration data to add to the limited knowledge about this topic. Aim We examined predictors of turnover intention, or an employee's cognitive withdrawal from their job, in a large sample of direct care mental health professionals, separating among occupations to increase the pragmatic relevance of our findings. Method Survey data from 10 997 mental health employees working in direct patient contact (2432 registered nurses, 3769 social workers, 2520 psychologists and 1276 psychiatrists) were used in a cross-sectional design with structural equation modelling techniques for model testing. Results Job satisfaction was predicted by civility (courteous and respectful workplace behaviours) and supervisory support. Job satisfaction predicted emotional exhaustion which predicted turnover intention. Job satisfaction also directly predicted turnover intention and turnover plans. Discussion Predictors of job satisfaction included civility and supervisory support. Emotional exhaustion predicted turnover intention. Results inform organizational actions to address these work environment characteristics. Implications for practice Organizations can initiate culture changes to improve civility and develop supervisors' 'soft skills' in conjunction with technical expertise. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Perinatal exposure to methadone affects central cholinergic activity in the weanling rat.

PubMed

Robinson, S E; Mo, Q; Maher, J R; Wallace, M J; Kunko, P M

1996-06-01

Pregnant rats were implanted with osmotic minipumps containing either methadone hydrochloride (initial dose, 9 mg/kg/day) or sterile water. Their offspring were cross-fostered so that they were exposed to methadone prenatally and/or postnatally. Perinatal methadone exposure disrupted cholinergic activity on postnatal day 21 as measured by the turnover rate of acetylcholine (TRACh) in both female and male rats, although there were some sexually-dimorphic responses. The most profoundly affected brain region was the striatum, where prenatal exposure to methadone increased ACh turnover, whether or not the rats continued to be exposed to methadone postnatally. It appears unlikely that neonatal withdrawal contributes to brain regional changes in ACh turnover, as continued postnatal exposure to methadone did not prevent the prenatal methadone induced changes.

Metabolic labeling reveals proteome dynamics of mouse mitochondria.

PubMed

Kim, Tae-Young; Wang, Ding; Kim, Allen K; Lau, Edward; Lin, Amanda J; Liem, David A; Zhang, Jun; Zong, Nobel C; Lam, Maggie P Y; Ping, Peipei

2012-12-01

Mitochondrial dysfunction is associated with many human diseases. Mitochondrial damage is exacerbated by inadequate protein quality control and often further contributes to pathogenesis. The maintenance of mitochondrial functions requires a delicate balance of continuous protein synthesis and degradation, i.e. protein turnover. To understand mitochondrial protein dynamics in vivo, we designed a metabolic heavy water ((2)H(2)O) labeling strategy customized to examine individual protein turnover in the mitochondria in a systematic fashion. Mice were fed with (2)H(2)O at a minimal level (<5% body water) without physiological impacts. Mitochondrial proteins were analyzed from 9 mice at each of the 13 time points between 0 and 90 days (d) of labeling. A novel multiparameter fitting approach computationally determined the normalized peak areas of peptide mass isotopomers at initial and steady-state time points and permitted the protein half-life to be determined without plateau-level (2)H incorporation. We characterized the turnover rates of 458 proteins in mouse cardiac and hepatic mitochondria and found median turnover rates of 0.0402 d(-1) and 0.163 d(-1), respectively, corresponding to median half-lives of 17.2 d and 4.26 d. Mitochondria in the heart and those in the liver exhibited distinct turnover kinetics, with limited synchronization within functional clusters. We observed considerable interprotein differences in turnover rates in both organs, with half-lives spanning from hours to months (≈ 60 d). Our proteomics platform demonstrates the first large-scale analysis of mitochondrial protein turnover rates in vivo, with potential applications in translational research.

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor.

PubMed

van Schie, Morten M C H; Pedroso de Almeida, Tiago; Laudadio, Gabriele; Tieves, Florian; Fernández-Fueyo, Elena; Noël, Timothy; Arends, Isabel W C E; Hollmann, Frank

2018-01-01

The biocatalytic preparation of trans -hex-2-enal from trans -hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii ( Pe AAOx) is reported. As O 2 -dependent enzyme Pe AAOx-dependent reactions are generally plagued by the poor solubility of O 2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s -1 ) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme.

AK-cut crystal resonators

NASA Technical Reports Server (NTRS)

Kahan, A.; Euler, F. K.

1983-01-01

Calculations have predicted the existence of crystallographically doubly rotated quartz orientations with turnover temperatures which are considerably less sensitive to angular misorientation then comparable AT- or BT-cuts. These crystals are arbitrarily designated as the AK-cut. Experimental data is given for seven orientations, phi-angle variations between 30-46 deg and theta-angle variations between 21-28 deg measured on 3.3-3.4 MHz fundamental mode resonators vibrating in the thickness shear c-mode. The experimental turnover temperatures of these resonators are between 80 C and 150 C, in general agreement with calculated values. The normalized frequency change as a function of temperature has been fitted with a cubic equation.

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

PubMed Central

van Schie, Morten M C H; Pedroso de Almeida, Tiago; Laudadio, Gabriele; Tieves, Florian; Fernández-Fueyo, Elena; Arends, Isabel W C E

2018-01-01

The biocatalytic preparation of trans-hex-2-enal from trans-hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) is reported. As O2-dependent enzyme PeAAOx-dependent reactions are generally plagued by the poor solubility of O2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s−1) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme. PMID:29719567

Temperature & wood source control PyOM turnover in a Northern American forest

NASA Astrophysics Data System (ADS)

Hatton, Pierre-Joseph; Le Moine, James; Auclerc, Apolline; Gormley, Mark; Filley, Tim R.; Nadelhoffer, Knute J.; Bird, Jeff. A.

2016-04-01

Surprisingly little is known about how pyrolysis temperature and wood source affect the stability of forest-fire derived pyrogenic organic matter (PyOM). Here, we show that wood source and temperature affect in situ mineralization rates of PyOM in soils for two co-occurring gymnosperm (jack pine; JP [Pinus banksiana]) and angiosperm (red maple; RM [Acer rubrum])¬ species from North American boreal-temperate ecotones. We assess the effect of pyrolysis temperature on PyOM fates by following the decay of 13C/15N-enriched JP wood (JPwood) and PyOM produced at 300 °C (JP300) and 450 °C (JP450); and assess the effect of PyOM wood source by comparing fates of JP450 and RM450. JPwood mineralized 18× faster than JP300 and 44× faster than JP450 after 2.8y. RM450 mineralized initially faster than JP450 during the first ~2y, but became equivalent afterwards (1.1±0.2% of CO¬2 losses after 2.8y). Modeled turnover times suggest that this can be attributed to ~1% of fast-cycling PyOM (<3y). Slower-cycling pools are 12× faster for JPwood (13±5y) than for JP300 (157±28y) and 55× faster than for JP450 (700±229y). Modeled turnover times of the slow-cycling pools were equivalent for JP450 and RM450. The priming effect was positive for JPwood (0.10±0.05), neutral for JP300 (-0.02±0.04), and negative for JP450 (-0.15±0.03) and RM50 (-0.59±0.03). DOC losses were minimal compared with CO2 losses (DOC:CO2 ratio ≤0.005), but followed the same patterns: JPwood 6× greater than that of JP300 and 39× greater compared with JP450. After 1y, C recoveries were lower for JPwood than for PyOM, with no influence of pyrolysis temperature or wood source (yet); N recoveries did not differ. PLFA-(13)C data reveal that (i) treatments have similar microbial communities after 1y, (ii) JPwood is preferentially utilized by fungi, and (iii) bacteria increasingly utilize PyOM as pyrolysis temperature increases. Estimated carbon use efficiency decreased with increasing pyrolysis temperature (JPwood~JP300>JP450~RM450). Although insignificant, potential phenol oxidase and peroxidase activities decrease with increasing pyrolysis temperature. Neither PyOM nor wood additions (~11% of soil C stock 0-20 cm depth) affected pH or Ec after 1y. We provide the first, field experimental evidence that pyrolysis temperature and wood source affect the turnover of PyOM in soil. We show faster, initial decay for PyOM produced at lesser temperature and RM (angiosperm) compared with JP (gymnosperm). This study offers realistic insights on (i) the controls underlying in situ PyOM turnover, and on (ii) how ongoing/projected changes in tree species composition and fire frequency/intensity/distribution may affect PyOM in soil of North America temperate-boreal ecotones.

Effect of low-magnitude different-frequency whole-body vibration on subchondral trabecular bone microarchitecture, cartilage degradation, bone/cartilage turnover, and joint pain in rabbits with knee osteoarthritis.

PubMed

Junbo, Wang; Sijia, Liu; Hongying, Chen; Lei, Liu; Pu, Wang

2017-06-15

Whole-body vibration(WBV) has been suggested for the prevention of subchondral bone loss of knee osteoarthritis (OA) . This study examined the effects of different frequency of whole-body vibration on subchondral trabecular bone microarchitecture, cartilage degradation and metabolism of the tibia and femoral condyle bone, and joint pain in an anterior cruciate ligament transection (ACLT)-induced knee osteoarthritisrabbit model. Ninety adult rabbits were divided into six groups: all groups received unilateral ACLT; Group 1, ACLT only; Group 2, 5 Hz WBV; Group 3, 10 Hz WBV; Group 4, 20 Hz WBV; Group 5, 30 Hz WBV; and Group 6, 40 Hz WBV. Pain was tested via weight-bearing asymmetry. Subchondral trabecular bone microarchitecture was examined using in vivo micro-computed tomography. Knee joint cartilage was evaluated by gross morphology, histology, and ECM gene expression level (aggrecan and type II collagen [CTX-II]). Serum bone-specific alkaline phosphatase, N-mid OC, cartilage oligometric protein, CPII, type I collagen, PIIANP, G1/G2 aggrecan levels, and urinary CTX-II were analyzed. After 8 weeks of low-magnitude WBV, the lower frequency (10 Hz and 20 Hz) WBV treatment decreased joint pain and cartilage resorption, accelerated cartilage formation, delayed cartilage degradation especially at the 20 Hz regimen. However, the higher frequencies (30 Hz and 40 Hz) had worse effects, with worse limb function and cartilage volume as well as higher histological scores and cartilage resorption. In contrast, both prevented loss of trabeculae and increased bone turnover. No significant change was observed in the 5 Hz WBV group. Our data demonstrate that the lower frequencies (10 Hz and 20 Hz) of low-magnitude WBV increased bone turnover, delayed cartilage degeneration, and caused a significant functional change of the OA-affected limb in ACLT-induced OA rabbit model but did not reverse OA progression after 8 weeks of treatment.

Atomically dispersed Ni(i) as the active site for electrochemical CO2 reduction

NASA Astrophysics Data System (ADS)

Yang, Hong Bin; Hung, Sung-Fu; Liu, Song; Yuan, Kaidi; Miao, Shu; Zhang, Liping; Huang, Xiang; Wang, Hsin-Yi; Cai, Weizheng; Chen, Rong; Gao, Jiajian; Yang, Xiaofeng; Chen, Wei; Huang, Yanqiang; Chen, Hao Ming; Li, Chang Ming; Zhang, Tao; Liu, Bin

2018-02-01

Electrochemical reduction of CO2 to chemical fuel offers a promising strategy for managing the global carbon balance, but presents challenges for chemistry due to the lack of effective electrocatalyst. Here we report atomically dispersed nickel on nitrogenated graphene as an efficient and durable electrocatalyst for CO2 reduction. Based on operando X-ray absorption and photoelectron spectroscopy measurements, the monovalent Ni(i) atomic center with a d9 electronic configuration was identified as the catalytically active site. The single-Ni-atom catalyst exhibits high intrinsic CO2 reduction activity, reaching a specific current of 350 A gcatalyst-1 and turnover frequency of 14,800 h-1 at a mild overpotential of 0.61 V for CO conversion with 97% Faradaic efficiency. The catalyst maintained 98% of its initial activity after 100 h of continuous reaction at CO formation current densities as high as 22 mA cm-2.

Changing Hours of Work: A Review and Analysis of the Research.

ERIC Educational Resources Information Center

Glueck, William F.

1979-01-01

Reviews the literature on the positive and negative effects of compressed work weeks and flextime on employee performance, satisfaction, absenteeism and tardiness, and turnover, as well as their effect on the quality of work done and the frequency of accidents. (IRT)

Two novel bursting patterns in the Duffing system with multiple-frequency slow parametric excitations

NASA Astrophysics Data System (ADS)

Han, Xiujing; Zhang, Yi; Bi, Qinsheng; Kurths, Jürgen

2018-04-01

This paper aims to report two novel bursting patterns, the turnover-of-pitchfork-hysteresis-induced bursting and the compound pitchfork-hysteresis bursting, demonstrated for the Duffing system with multiple-frequency parametric excitations. Typically, a hysteresis behavior between the origin and non-zero equilibria of the fast subsystem can be observed due to delayed pitchfork bifurcation. Based on numerical analysis, we show that the stable equilibrium branches, related to the non-zero equilibria resulted from the pitchfork bifurcation, may become the ones with twists and turns. Then, the novel bursting pattern turnover-of-pitchfork-hysteresis-induced bursting is revealed accordingly. In particular, we show that additional pitchfork bifurcation points may appear in the fast subsystem under certain parameter conditions. This creates multiple delay-induced hysteresis behavior and helps us to reveal the other novel bursting pattern, the compound pitchfork-hysteresis bursting. Besides, effects of parameters on the bursting patterns are studied to explore the relation of these two novel bursting patterns.

Atomic oxygen production scaling in a nanosecond-pulsed externally grounded dielectric barrier plasma jet

NASA Astrophysics Data System (ADS)

Sands, Brian; Schmidt, Jacob; Ganguly, Biswa; Scofield, James

2014-10-01

Atomic oxygen production is studied in a capillary dielectric barrier plasma jet that is externally grounded and driven with a 20-ns risetime positive unipolar pulsed voltage at pulse repetition rates up to 25 kHz. The power coupled to the discharge can be easily increased by increasing the pulse repetition rate. At a critical turnover frequency, determined by the net energy density coupled to the discharge, the plasma chemistry abruptly changes. This is indicated by increased plasma conductance and a transition in reactive oxygen species production from an ozone-dominated production regime below the turnover frequency to atomic-oxygen-dominated production at higher pulse rates. Here, we characterize atomic oxygen production scaling using spatially- and temporally-resolved two-photon absorption laser-induced-fluorescence (TALIF). Quantitative results are obtained via calibration with xenon using a similar laser excitation and collection system. These results are compared with quantitative ozone and discharge power measurements using a helium gas flow with oxygen admixtures up to 3%.

Chief nursing officer turnover: chief nursing officers and healthcare recruiters tell their stories.

PubMed

Havens, Donna Sullivan; Thompson, Pamela A; Jones, Cheryl B

2008-12-01

Chief nursing officers (CNOs) develop environments in which quality patient care is delivered and nurses enjoy professional practice. Because of the growing turbulence in this vital role, the American Organization of Nurse Executives conducted a study to examine CNO turnover as described in interviews with CNOs and healthcare recruiters to inform the development of strategies to improve CNO recruitment and retention and ease transition for those who turn over. The authors present the findings from this research and describe American Organization of Nurse Executives' initiatives to address the identified needs.

Unraveling the Role of Podocyte Turnover in Glomerular Aging and Injury

PubMed Central

Wanner, Nicola; Hartleben, Björn; Herbach, Nadja; Goedel, Markus; Stickel, Natalie; Zeiser, Robert; Walz, Gerd; Moeller, Marcus J.; Grahammer, Florian

2014-01-01

Podocyte loss is a major determinant of progressive CKD. Although recent studies showed that a subset of parietal epithelial cells can serve as podocyte progenitors, the role of podocyte turnover and regeneration in repair, aging, and nephron loss remains unclear. Here, we combined genetic fate mapping with highly efficient podocyte isolation protocols to precisely quantify podocyte turnover and regeneration. We demonstrate that parietal epithelial cells can give rise to fully differentiated visceral epithelial cells indistinguishable from resident podocytes and that limited podocyte renewal occurs in a diphtheria toxin model of acute podocyte ablation. In contrast, the compensatory programs initiated in response to nephron loss evoke glomerular hypertrophy, but not de novo podocyte generation. In addition, no turnover of podocytes could be detected in aging mice under physiologic conditions. In the absence of podocyte replacement, characteristic features of aging mouse kidneys included progressive accumulation of oxidized proteins, deposits of protein aggregates, loss of podocytes, and glomerulosclerosis. In summary, quantitative investigation of podocyte regeneration in vivo provides novel insights into the mechanism and capacity of podocyte turnover and regeneration in mice. Our data reveal that podocyte generation is mainly confined to glomerular development and may occur after acute glomerular injury, but it fails to regenerate podocytes in aging kidneys or in response to nephron loss. PMID:24408871

Intention to leave the profession: antecedents and role in nurse turnover.

PubMed

Parry, Julianne

2008-10-01

This paper is a report of a study to examine the relationship between intention to change profession and intention to change employer among newly graduated nurses. Few studies of the worldwide nursing workforce shortage consider the contribution of changing professions to the shortage. Organizational behaviour research has identified that professional commitment and organizational commitment have an important role in organizational turnover and that professional commitment and intention to change professions may have a greater role in organizational turnover than is presently understood. A model of the relationships between affective professional commitment job satisfaction, organizational commitment, intention to change professions and organizational turnover intention was developed through review of the organizational behaviour literature and tested using path analysis. The sample was drawn from all nurses in Queensland, Australia, entering the workforce for the first time in 2005. The model was tested with a final sample size of 131 nurses in the initial period of exposure to the workplace. Affective professional commitment and organizational commitment were statistically significantly related to intention to change professions. Job satisfaction, organizational commitment and intention to change professions were statistically significantly related to intention to change employer. Turnover research in nursing should include intention to change professions as well as intention to change employer. Policies and practices that enhance the development of affective professional commitment prior to exposure to the workplace and support affective professional commitment, job satisfaction and organizational commitment in the workplace are needed to help reduce nurse turnover.

24 CFR 904.206 - Funding.

Code of Federal Regulations, 2010 CFR

2010-04-01

... the initial counseling and training there is likely to be some turnover and follow-up counseling and... community resources to be utilized; (v) The methods of counseling and training to be utilized; (vi) The...

Health Care Workplace Discrimination and Physician Turnover

PubMed Central

Nunez-Smith, Marcella; Pilgrim, Nanlesta; Wynia, Matthew; Desai, Mayur M.; Bright, Cedric; Krumholz, Harlan M.; Bradley, Elizabeth H.

2013-01-01

Objective To examine the association between physician race/ethnicity, workplace discrimination, and physician job turnover. Methods Cross-sectional, national survey conducted in 2006–2007 of practicing physicians [n = 529] randomly identified via the American Medical Association Masterfile and The National Medical Association membership roster. We assessed the relationships between career racial/ethnic discrimination at work and several career-related dependent variables, including 2 measures of physician turnover, career satisfaction, and contemplation of career change. We used standard frequency analyses, odds ratios and χ2 statistics, and multivariate logistic regression modeling to evaluate these associations. Results Physicians who self-identified as nonmajority were significantly more likely to have left at least 1 job because of workplace discrimination (black, 29%; Asian, 24%; other race, 21%; Hispanic/Latino, 20%; white, 9%). In multivariate models, having experienced racial/ethnic discrimination at work was associated with high job turnover [adjusted odes ratio, 2.7; 95% CI, 1.4–4.9]. Among physicians who experienced work-place discrimination, only 45% of physicians were satisfied with their careers (vs 88% among those who had not experienced workplace discrimination, p value < .01], and 40% were con-templating a career change (vs 10% among those who had not experienced workplace discrimination, p value < .001). Conclusion Workplace discrimination is associated with physician job turnover, career dissatisfaction, and contemplation of career change. These findings underscore the importance of monitoring for workplace discrimination and responding when opportunities for intervention and retention still exist. PMID:20070016

The relationships between organisational citizenship behaviour, job satisfaction and turnover intention.

PubMed

Tsai, Yafang; Wu, Shih-Wang

2010-12-01

This study aims to explore the relationships between organisational citizenship behaviour, job satisfaction and turnover intention. Because of the changing health policies landscape, Taiwan's hospital administrators are facing major cost reduction challenges. Specifically, the high turnover rate of nurses represents a hindrance and a human resource cost. This study focuses on ways of reducing the employee turnover rate through enhanced organisational citizenship behaviour and job satisfaction. A cross-sectional study. This study focuses on hospital nurses in Taiwan. Our research samples were obtained from one medical centre, three regional hospitals and seven district hospitals. Out of 300 questionnaires distributed among samples, 237 were completed and returned. Pearson's correlation was used to test for relationships among the main variables. One-way analysis of variance and Scheffé's post hoc analysis were employed to test the influence of demographic data on the main variables. The results reveal that the nurses' job satisfaction has a significantly positive correlation with organisational citizenship behaviour and a negative correlation with turnover intention. This study has proven that the turnover intention of clinical nurses is related to their organisational citizenship behaviour and job satisfaction. Hospital administrators can reduce the turnover intention by meeting nurses' needs and by promoting their organisational citizenship behaviour. Organisational citizenship behaviour involves behaviour that encourages staff to endeavour to voluntarily improve organisational performance without lobbying for compensation. Employees' job satisfaction includes satisfaction with the working environment or welfare programme in the context of human resource initiatives. Similarly, human resource protocols may serve as the starting point for promoting staff organisational citizenship behaviour. Administrators in clinical healthcare are encouraged to meet their employees' working needs through human resource practices. © 2010 Blackwell Publishing Ltd.

Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography

PubMed Central

Vogel, Hans-Jörg

2016-01-01

Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3). We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity) nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other. PMID:27453995

How does single party dominance influence civil society organisations’ engagement strategies? Exploratory analysis of participative mainstreaming in a ‘regional’ European polity

PubMed Central

2015-01-01

A raft of United Nations Treaties, European Union Directives and domestic laws oblige governments in 180 + countries to apply the Participative Democratic Model of mainstreaming equalities to public administration by involving those targeted by equality initiatives at all stages in their design and delivery. Notwithstanding Participative Democratic Model’s deeply political nature, extant work has overlooked how governing party turnover influences civil society organisations’ (CSOs) strategies. Here, this lacuna is addressed using a negative ‘extreme case study’ research design involving qualitative accounts from civil society organisations in Wales, a ‘regional’ European polity characterised by one-party dominance. The findings reveal how the absence of turnover distorts the Participative Democratic Model in relation to diverse factors including: strategic bridging, extraparliamentary politics, cognitive locks and party institutionalisation. Inter alia, the wider contribution of this analysis lies in showing the importance of turnover to effective engagement, the ‘pathologies’ associated with one-party dominance and the need for adaptive civil society strategies tailored to prevailing electoral politics and governing party turnover in liberal democracies. PMID:28596639

How does single party dominance influence civil society organisations' engagement strategies? Exploratory analysis of participative mainstreaming in a 'regional' European polity.

PubMed

Chaney, Paul

2016-04-01

A raft of United Nations Treaties, European Union Directives and domestic laws oblige governments in 180 + countries to apply the Participative Democratic Model of mainstreaming equalities to public administration by involving those targeted by equality initiatives at all stages in their design and delivery. Notwithstanding Participative Democratic Model's deeply political nature, extant work has overlooked how governing party turnover influences civil society organisations' (CSOs) strategies. Here, this lacuna is addressed using a negative 'extreme case study' research design involving qualitative accounts from civil society organisations in Wales, a 'regional' European polity characterised by one-party dominance. The findings reveal how the absence of turnover distorts the Participative Democratic Model in relation to diverse factors including: strategic bridging, extraparliamentary politics, cognitive locks and party institutionalisation. Inter alia, the wider contribution of this analysis lies in showing the importance of turnover to effective engagement, the 'pathologies' associated with one-party dominance and the need for adaptive civil society strategies tailored to prevailing electoral politics and governing party turnover in liberal democracies.

Mapping the core mass function to the initial mass function

NASA Astrophysics Data System (ADS)

Guszejnov, Dávid; Hopkins, Philip F.

2015-07-01

It has been shown that fragmentation within self-gravitating, turbulent molecular clouds (`turbulent fragmentation') can naturally explain the observed properties of protostellar cores, including the core mass function (CMF). Here, we extend recently developed analytic models for turbulent fragmentation to follow the time-dependent hierarchical fragmentation of self-gravitating cores, until they reach effectively infinite density (and form stars). We show that turbulent fragmentation robustly predicts two key features of the initial mass function (IMF). First, a high-mass power-law scaling very close to the Salpeter slope, which is a generic consequence of the scale-free nature of turbulence and self-gravity. We predict the IMF slope (-2.3) is slightly steeper than the CMF slope (-2.1), owing to the slower collapse and easier fragmentation of large cores. Secondly, a turnover mass, which is set by a combination of the CMF turnover mass (a couple solar masses, determined by the `sonic scale' of galactic turbulence, and so weakly dependent on galaxy properties), and the equation of state (EOS). A `soft' EOS with polytropic index γ < 1.0 predicts that the IMF slope becomes `shallow' below the sonic scale, but fails to produce the full turnover observed. An EOS, which becomes `stiff' at sufficiently low surface densities Σgas ˜ 5000 M⊙ pc-2, and/or models, where each collapsing core is able to heat and effectively stiffen the EOS of a modest mass (˜0.02 M⊙) of surrounding gas, are able to reproduce the observed turnover. Such features are likely a consequence of more detailed chemistry and radiative feedback.

Personality Traits Associated with Occupational "Burnout" in ABA Therapists

ERIC Educational Resources Information Center

Hurt, Amy A.; Grist, Cathy Lann; Malesky, Lann A., Jr.; McCord, David M.

2013-01-01

Background: Applied behaviour analysis (ABA) therapists typically work one-to-one with children with autism for extended periods of time, which often leads to high levels of job-related stress, lower levels of job satisfaction, increased frequency of occupational "burnout" and higher than average job turnover (Journal of Autism…

Progress Report for a New Cryogenic Sapphire Oscillator

NASA Technical Reports Server (NTRS)

Wang, Rabi T.; Dick, G. J.; Tjoelker, R. L.

2006-01-01

We present design progress and subsystem test results for a new short-term frequency standard, the Voltage Controlled Sapphire Oscillator (VCSO). Included are sapphire resonator and coupling design, cryocooler environmental sensitivity tests, Q measurement results, and turnover temperature results. A previous report presented history of the design related to resonator frequency and frequency compensation [1]. Performance goals are a frequency stability of 1x10(exp -14) (1 second less than or equal to (tau) less than or equal to 100 seconds) and two years or more continuous operation. Long-term operation and small size are facilitated by use of a small Stirling cryo-cooler (160W wall power) with an expected 5 year life.

The impact of financial and nonfinancial incentives on business-unit outcomes over time.

PubMed

Peterson, Suzanne J; Luthans, Fred

2006-01-01

Unlike previous behavior management research, this study used a quasi-experimental, control group design to examine the impact of financial and nonfinancial incentives on business-unit (21 stores in a fast-food franchise corporation) outcomes (profit, customer service, and employee turnover) over time. The results showed that both types of incentives had a significant impact on all measured outcomes. The financial incentive initially had a greater effect on all 3 outcomes, but over time, the financial and nonfinancial incentives had an equally significant impact except in terms of employee turnover. (c) 2006 APA, all rights reserved.

Leaf and fine root carbon stocks and turnover are coupled across Arctic ecosystems.

PubMed

Sloan, Victoria L; Fletcher, Benjamin J; Press, Malcolm C; Williams, Mathew; Phoenix, Gareth K

2013-12-01

Estimates of vegetation carbon pools and their turnover rates are central to understanding and modelling ecosystem responses to climate change and their feedbacks to climate. In the Arctic, a region containing globally important stores of soil carbon, and where the most rapid climate change is expected over the coming century, plant communities have on average sixfold more biomass below ground than above ground, but knowledge of the root carbon pool sizes and turnover rates is limited. Here, we show that across eight plant communities, there is a significant positive relationship between leaf and fine root turnover rates (r(2) = 0.68, P < 0.05), and that the turnover rates of both leaf (r(2) = 0.63, P < 0.05) and fine root (r(2) = 0.55, P < 0.05) pools are strongly correlated with leaf area index (LAI, leaf area per unit ground area). This coupling of root and leaf dynamics supports the theory of a whole-plant economics spectrum. We also show that the size of the fine root carbon pool initially increases linearly with increasing LAI, and then levels off at LAI = 1 m(2) m(-2), suggesting a functional balance between investment in leaves and fine roots at the whole community scale. These ecological relationships not only demonstrate close links between above and below-ground plant carbon dynamics but also allow plant carbon pool sizes and their turnover rates to be predicted from the single readily quantifiable (and remotely sensed) parameter of LAI, including the possibility of estimating root data from satellites. © 2013 John Wiley & Sons Ltd.

Changes in bone turnover markers with HIV seroconversion and ART initiation

PubMed Central

Slama, Laurence; Reddy, Susheel; Phair, John; Palella, Frank J.; Brown, Todd T.

2017-01-01

Background: Osteoporosis is common among HIV-infected persons and contributes to risk of fragility fracture. While ART initiation is associated with decreases in bone mineral density and increases in bone turnover, the impact of HIV on bone metabolism is unclear. Methods: We identified men at the Chicago site of the Multicenter AIDS Cohort Study who HIV seroconverted while under observation. Concentrations of 25-OH vitamin D, bone turnover markers [procollagen type 1 N terminal propeptide (P1NP), osteocalcin (OC), C-telopeptide (CTX)] and sclerostin were measured from stored serum obtained at pre-HIV infection, pre-ART and post-ART initiation timepoints. Mixed models, with each biomarker as an outcome, were fitted. Timepoint, age, CD4 count (cells/mm3), HIV-viral suppression, season and an age by timepoint interaction term were considered as fixed effects. Results: Data from 52 participants revealed that median duration between HIV seroconversion and ART initiation was 8.7 years (IQR 3.7–11.6). Median CD4 and plasma HIV-RNA concentrations were 445 (IQR 298.5–689) and 20 184 copies/mL (IQR 6237–64 340), respectively, at the pre-ART timepoint. Multivariate analyses demonstrated pre-HIV infection levels of OC that were higher than pre-ART levels (6.8 versus 5.7 ng/mL, P = 0.04); and pre-ART levels of sclerostin that were higher than post-ART levels (0.033 versus 0.02 ng/mL, P <0.001). No changes in P1NP, CTX and 25-OH vitamin D levels were detected. Conclusions: HIV seroconversion was associated with decreased OC levels while ART initiation was associated with decreases in sclerostin, a negative regulator of bone formation. Our results suggest that both HIV infection and ART have an impact on bone metabolism in white men. PMID:28175307

Changes in bone turnover markers with HIV seroconversion and ART initiation.

PubMed

Slama, Laurence; Reddy, Susheel; Phair, John; Palella, Frank J; Brown, Todd T

2017-05-01

Osteoporosis is common among HIV-infected persons and contributes to risk of fragility fracture. While ART initiation is associated with decreases in bone mineral density and increases in bone turnover, the impact of HIV on bone metabolism is unclear. We identified men at the Chicago site of the Multicenter AIDS Cohort Study who HIV seroconverted while under observation. Concentrations of 25-OH vitamin D, bone turnover markers [procollagen type 1 N terminal propeptide (P1NP), osteocalcin (OC), C-telopeptide (CTX)] and sclerostin were measured from stored serum obtained at pre-HIV infection, pre-ART and post-ART initiation timepoints. Mixed models, with each biomarker as an outcome, were fitted. Timepoint, age, CD4 count (cells/mm 3 ), HIV-viral suppression, season and an age by timepoint interaction term were considered as fixed effects. Data from 52 participants revealed that median duration between HIV seroconversion and ART initiation was 8.7 years (IQR 3.7-11.6). Median CD4 and plasma HIV-RNA concentrations were 445 (IQR 298.5-689) and 20 184 copies/mL (IQR 6237-64 340), respectively, at the pre-ART timepoint. Multivariate analyses demonstrated pre-HIV infection levels of OC that were higher than pre-ART levels (6.8 versus 5.7 ng/mL, P  =   0.04); and pre-ART levels of sclerostin that were higher than post-ART levels (0.033 versus 0.02 ng/mL, P  <0.001). No changes in P1NP, CTX and 25-OH vitamin D levels were detected. HIV seroconversion was associated with decreased OC levels while ART initiation was associated with decreases in sclerostin, a negative regulator of bone formation. Our results suggest that both HIV infection and ART have an impact on bone metabolism in white men. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

In situ formed catalytically active ruthenium nanocatalyst in room temperature dehydrogenation/dehydrocoupling of ammonia-borane from Ru(cod)(cot) precatalyst.

PubMed

Zahmakiran, Mehmet; Ayvalı, Tuğçe; Philippot, Karine

2012-03-20

The development of simply prepared and effective catalytic materials for dehydrocoupling/dehydrogenation of ammonia-borane (AB; NH(3)BH(3)) under mild conditions remains a challenge in the field of hydrogen economy and material science. Reported herein is the discovery of in situ generated ruthenium nanocatalyst as a new catalytic system for this important reaction. They are formed in situ during the dehydrogenation of AB in THF at 25 °C in the absence of any stabilizing agent starting with homogeneous Ru(cod)(cot) precatalyst (cod = 1,5-η(2)-cyclooctadiene; cot = 1,3,5-η(3)-cyclooctatriene). The preliminary characterization of the reaction solutions and the products was done by using ICP-OES, ATR-IR, TEM, XPS, ZC-TEM, GC, EA, and (11)B, (15)N, and (1)H NMR, which reveal that ruthenium nanocatalyst is generated in situ during the dehydrogenation of AB from homogeneous Ru(cod)(cot) precatalyst and B-N polymers formed at the initial stage of the catalytic reaction take part in the stabilization of this ruthenium nanocatalyst. Moreover, following the recently updated approach (Bayram, E.; et al. J. Am. Chem. Soc.2011, 133, 18889) by performing Hg(0), CS(2) poisoning experiments, nanofiltration, time-dependent TEM analyses, and kinetic investigation of active catalyst formation to distinguish single metal or in the present case subnanometer Ru(n) cluster-based catalysis from polymetallic Ru(0)(n) nanoparticle catalysis reveals that in situ formed Ru(n) clusters (not Ru(0)(n) nanoparticles) are kinetically dominant catalytically active species in our catalytic system. The resulting ruthenium catalyst provides 120 total turnovers over 5 h with an initial turnover frequency (TOF) value of 35 h(-1) at room temperature with the generation of more than 1.0 equiv H(2) at the complete conversion of AB to polyaminoborane (PAB; [NH(2)BH(2)](n)) and polyborazylene (PB; [NHBH](n)) units.

Mentoring in Early Childhood Professional Development: Evaluation of the Rhode Island Child Development Specialist Apprenticeship Program

ERIC Educational Resources Information Center

Uttley, Clarissa M.; Horm, Diane M.

2008-01-01

The Quality Child Care Initiative, the federal apprenticeship program applied to the field of early care and education, has been implemented in over 40 states. This federal initiative was designed to reduce turnover, increase wages, provide a more stable environment for children, and lower the concern of parents. Rhode Island received funding in…

The Research to Action Project: Applied Workplace Solutions for Nurses.

PubMed

Silas, Linda

2012-03-01

The number of new nurses entering the profession has increased, but the need to retain nurses in the profession continues to be a critical priority. The consequences of the nursing shortage are reflected in continued high levels of overtime, absenteeism and turnover. The Canadian Federation of Nurses Unions (CFNU), in partnership with the Canadian Nurses Association, the Canadian Healthcare Association and the Dietitians of Canada, initiated the project Research to Action: Applied Workplace Solutions for Nurses (RTA). The RTA initiative comprised research-based pilot projects, implemented in 10 jurisdictions across the country, that aimed to improve workplaces and increase the retention and recruitment of nurses. Unions, employers, governments, universities and professional associations came together in an unprecedented show of collaboration. Lessons and knowledge were shared among the projects, which were evaluated for their viability in other jurisdictions and professions. The pilots led to increased leadership, engagement and professional development, and decreased overtime, absenteeism and turnover.

Identification of variants of CYP3A4 and characterization of their abilities to metabolize testosterone and chlorpyrifos.

PubMed

Dai, D; Tang, J; Rose, R; Hodgson, E; Bienstock, R J; Mohrenweiser, H W; Goldstein, J A

2001-12-01

CYP3A4 is the most abundant isoform of cytochrome P450 (CYP) in adult human liver. It metabolizes numerous clinically, physiologically, and toxicologically important compounds. The expression of CYP3A4 varies 40-fold in individual human livers, and metabolism of CYP3A4 substrates varies at least 10-fold in vivo. Single nucleotide polymorphisms (SNPs) in CYP3A4 were identified by direct sequencing of genomic DNA in 72 individuals from three different ethnic groups, including Caucasians, Blacks (African-Americans and African pygmies), and Asians. A total of 28 SNPs were identified, including five which produced coding changes M445T (CYP3A4*3), R162Q (CYP3A4*15), F189S (CYP3A4*17), L293P (CYP3A4*18), and P467S (CYP3A4*19). The latter four represent new alleic variants. Racial variability was observed for the frequency of individual SNPs. CYP3A R162Q was identified only in Black populations with an allelic frequency of 4%. CYP3A4 F189S and CYP3A4 M445T were identified in Caucasians with allelic frequencies 2% and 4%, respectively. L293P and P467S were only observed in Asians at allelic frequencies of 2%. The cDNAs for the F189S, L293P, M445T, and P467S mutant alleles were constructed by site-directed mutagenesis and expressed in an Escherichia coli expression system. Testosterone and the insecticide chlorpyrifos were used to assess the catalytic activities of the most common CYP3A4 allele (CYP3A4*1) and its allelic variants. CYP3A4 F189S exhibited lower turnover numbers for testosterone and chlorpyrifos, while CYP3A4 L293P had higher turnover numbers for both substrates. The turnover numbers of the CYP3A4 M445T and P467S alleles to metabolize these compounds were not significantly different from those of wild-type CYP3A4.

Multi-frequency properties of synthetic blazar radio light curves within the shock-in-jet scenario

NASA Astrophysics Data System (ADS)

Fromm, C. M.; Fuhrmann, L.; Perucho, M.

2015-08-01

Context. Blazars are among the most powerful extragalactic objects as a sub-class of active galactic nuclei. They launch relativistic jets and their emitted radiation shows strong variability across the entire electro-magnetic spectrum. The mechanisms producing the variability are still controversial, and different models have been proposed to explain the observed variations in multi-frequency blazar light curves. Aims: We investigate the capabilities of the classical shock-in-jet model to explain and reconstruct the observed evolution of flares in the turnover frequency - turnover flux density (νm-Sm) plane and their frequency dependent light curve parameters. With a detailed parameter space study, we provide the framework for future, detailed comparisons of observed flare signatures with the shock-in-jet scenario. Methods: Based on the shock model, we compute synthetic single-dish light curves at different radio frequencies (2.6 to 345 GHz) and for different physical conditions in a conical jet (e.g. magnetic field geometry and Doppler factor). From those we extract the slopes of the different energy loss stages within the (νm-Sm) plane and deduce the frequency dependence of different light curve parameters, such as flare amplitude, time scale, and cross-band delays. Results: The evolution of the Doppler factor along the jet has the strongest influence on the evolution of the flare and on the frequency dependent light curve parameters. The synchrotron stage can be hidden in the Compton or in the adiabatic stage, depending mainly on the evolution of the Doppler factor, which makes it difficult to detect its signature in observations. In addition, we show that the time lags between different frequencies can be used as an efficient tool to better constrain the physical properties of these objects. Appendix A is available in electronic form at http://www.aanda.org

The Relationship between Teacher Satisfaction and Frequency of Interaction with Site Administration

ERIC Educational Resources Information Center

Schwartz, Adam G.

2012-01-01

The primary determinant of student achievement is the quality of the classroom teacher. Some teachers are naturally talented, but the majority of teachers become effective through classroom experience. Unfortunately, the teaching profession experiences a high rate of turnover; many teachers leave before reaching the peak of their effectiveness. If…

Unveiling N-protonation and anion-binding effects on Fe/N/C-catalysts for O2 reduction in PEM fuel cells

PubMed Central

Herranz, Juan; Jaouen, Frédéric; Lefèvre, Michel; Kramm, Ulrike I.; Proietti, Eric; Dodelet, Jean-Pol; Bogdanoff, Peter; Fiechter, Sebastian; Abs-Wurmbach, Irmgard; Bertrand, Patrick; Arruda, Thomas M.; Mukerjee, Sanjeev

2013-01-01

The high cost of proton-exchange-membrane fuel cells would be considerably reduced if platinumbased catalysts were replaced by iron-based substitutes, which have recently demonstrated comparable activity for oxygen reduction, but whose cause of activity decay in acidic medium has been elusive. Here, we reveal that the activity of Fe/N/C-catalysts prepared through a pyrolysis in NH3 is mostly imparted by acid-resistant FeN4-sites whose turnover frequency for the O2 reduction can be regulated by fine chemical changes of the catalyst surface. We show that surface N-groups protonate at pH 1 and subsequently bind anions. This results in decreased activity for the O2 reduction. The anions can be removed chemically or thermally, which restores the activity of acid-resistant FeN4-sites. These results are interpreted as an increased turnover frequency of FeN4-sites when specific surface N-groups protonate. These unprecedented findings provide new perspective for stabilizing the most active Fe/N/C-catalysts known to date. PMID:24179561

High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to γ-valerolactone

PubMed Central

Luo, Wenhao; Sankar, Meenakshisundaram; Beale, Andrew M.; He, Qian; Kiely, Christopher J.; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

2015-01-01

The catalytic hydrogenation of levulinic acid, a key platform molecule in many biorefinery schemes, into γ-valerolactone is considered as one of the pivotal reactions to convert lignocellulose-based biomass into renewable fuels and chemicals. Here we report on the development of highly active, selective and stable supported metal catalysts for this reaction and on the beneficial effects of metal nano-alloying. Bimetallic random alloys of gold-palladium and ruthenium-palladium supported on titanium dioxide are prepared with a modified metal impregnation method. Gold-palladium/titanium dioxide shows a marked,~27-fold increase in activity (that is, turnover frequency of 0.1 s−1) compared with its monometallic counterparts. Although ruthenium-palladium/titanium dioxide is not only exceptionally active (that is, turnover frequency of 0.6 s−1), it shows excellent, sustained selectivity to γ-valerolactone (99%). The dilution and isolation of ruthenium by palladium is thought to be responsible for this superior catalytic performance. Alloying, furthermore, greatly improves the stability of both supported nano-alloy catalysts. PMID:25779385

Unveiling N-protonation and anion-binding effects on Fe/N/C-catalysts for O2 reduction in PEM fuel cells.

PubMed

Herranz, Juan; Jaouen, Frédéric; Lefèvre, Michel; Kramm, Ulrike I; Proietti, Eric; Dodelet, Jean-Pol; Bogdanoff, Peter; Fiechter, Sebastian; Abs-Wurmbach, Irmgard; Bertrand, Patrick; Arruda, Thomas M; Mukerjee, Sanjeev

2011-11-18

The high cost of proton-exchange-membrane fuel cells would be considerably reduced if platinumbased catalysts were replaced by iron-based substitutes, which have recently demonstrated comparable activity for oxygen reduction, but whose cause of activity decay in acidic medium has been elusive. Here, we reveal that the activity of Fe/N/C-catalysts prepared through a pyrolysis in NH 3 is mostly imparted by acid-resistant FeN 4 -sites whose turnover frequency for the O 2 reduction can be regulated by fine chemical changes of the catalyst surface. We show that surface N-groups protonate at pH 1 and subsequently bind anions. This results in decreased activity for the O 2 reduction. The anions can be removed chemically or thermally, which restores the activity of acid-resistant FeN 4 -sites. These results are interpreted as an increased turnover frequency of FeN 4 -sites when specific surface N-groups protonate. These unprecedented findings provide new perspective for stabilizing the most active Fe/N/C-catalysts known to date.

Individual differences in pavlovian autoshaping of lever pressing in rats predict stress-induced corticosterone release and mesolimbic levels of monoamines.

PubMed

Tomie, A; Aguado, A S; Pohorecky, L A; Benjamin, D

2000-03-01

Pavlovian autoshaping CRs are directed and reflexive consummatory responses targeted at objects repeatedly paired with rewarding substances. To evaluate the hypothesis that autoshaping may provide an animal learning model of vulnerability to drug abuse, this study relates individual differences in lever-press autoshaping CR performance in rats to stress-induced corticosterone release and tissue monoamine levels in the mesolimbic dopamine tract. Long-Evans rats (n = 14) were given 20 sessions of Pavlovian autoshaping training wherein the insertion of a retractable lever CS was followed by the response-independent presentation of food US. Large between-subjects differences in lever-press autoshaping CR performance were observed, with group high CR frequency (n = 5) performing many more lever press CRs than group low CR frequency (n = 9). Tail-blood samples were obtained before and after the 20th autoshaping session, then 24 h later the rats were sacrificed and dissection yielded tissue samples of nucleus accumbens (NAC), prefrontal cortex (PFC), caudate putamen (CP), and ventral tegmental area (VTA). Serum levels of postsession corticosterone were elevated in group high CR frequency. HPLC revealed that group high CR frequency had higher tissue levels of dopamine and DOPAC in NAC, lower levels of DOPAC/DA turnover in CP, and lower levels of 5-HIAA and lower 5-HIAA/5-HT turnover in VTA. The neurochemical profile of rats that perform more autoshaping CRs share some features of vulnerability to drug abuse.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eggers, J.

Persons having handicaps have been more likely to be hired into hourly and weekly job categories than into professional categories. The extent to which this selectivity reflects the qualifications of applicants rather than prejudicial categorization of handicapped persons is unknown. Only 5% of all handicapped high school graduates enter college, as compared with 34.3% of nonhandicapped high school graduates, thus decreasing the availability of handicapped applicants for professional jobs. The data presented here on absenteeism from on-the-job injuries, illness, and personal leave and on frequency of turnover indicate that concern about these matters is no more justified in considering handicappedmore » persons for employment than nonhandicapped persons. An interesting statistic is the increase in absences for both groups in the second year of employment. Turnover data indicate that employees who leave do so in the largest numbers during their first year of employment. These results should not be construed to mean that the supervisor of a handicapped person has never had nor ever will have a problem with safety, attendance, or turnover; the results do suggest that these problems are no greater for handicapped than nonhandicapped employees. 1 ref., 7 tabs.« less

Bone turnover in postmenopausal osteoporosis. Effect of calcitonin treatment.

PubMed

Civitelli, R; Gonnelli, S; Zacchei, F; Bigazzi, S; Vattimo, A; Avioli, L V; Gennari, C

1988-10-01

To investigate the effectiveness of calcitonin treatment of postmenopausal osteoporosis in relation to bone turnover, we examined 53 postmenopausal osteoporotic women before and after one year of therapy with salmon calcitonin (sCT), at the dose of 50 IU every other day. Baseline evaluation revealed that 17 (32%) patients had high turnover (HTOP), and 36 (68%) normal turnover osteoporosis (NTOP) as assessed by measurement of whole body retention (WBR) of 99mTc-methylene diphosphonate. The two groups did not differ in terms of bone mineral content (BMC) measured by dual photon absorptiometry at both lumbar spine and femoral diaphysis. However, HTOP patients had higher levels of serum osteocalcin (OC) and urinary hydroxyproline excretion (HOP/Cr). Multivariate regression analysis showed no correlation between parameters of bone turnover (WBR, OC, HOP/Cr) and both femoral and vertebral bone density; the latter being negatively correlated only with the years elapsed since menopause (R2 = 0.406). Treatment with sCT resulted in a significant increase of vertebral BMC in the 53 patients taken as a whole group (+/- 7%, P less than 0.001). When the results obtained in HTOP and NTOP were analyzed separately, only those with HTOP showed a marked increment of spinal BMC (+22%, P less than 0.001), NTOP subjects neither gained nor lost bone mineral during the study. Femoral BMC decreased in the whole group after sCT therapy (-3%, P less than 0.003). However, HTOP patients maintained initial BMC values, whereas those with NTOP lost a significant amount of bone during the study period (-5%, P less than 0.001). The increase of vertebral bone mass was associated with a marked depression of bone turnover detectable in both subsets of patients and in the whole group. (a) assessment of bone turnover cannot help predict the severity of bone loss in postmenopausal osteoporosis; (b) calcitonin therapy appears to be particularly indicated for patients with high-turnover osteoporosis, resulting in a net gain of bone mineral in the axial skeleton and a slowing of bone loss in the appendicular bones.

Bone turnover in postmenopausal osteoporosis. Effect of calcitonin treatment.

PubMed Central

Civitelli, R; Gonnelli, S; Zacchei, F; Bigazzi, S; Vattimo, A; Avioli, L V; Gennari, C

1988-01-01

To investigate the effectiveness of calcitonin treatment of postmenopausal osteoporosis in relation to bone turnover, we examined 53 postmenopausal osteoporotic women before and after one year of therapy with salmon calcitonin (sCT), at the dose of 50 IU every other day. Baseline evaluation revealed that 17 (32%) patients had high turnover (HTOP), and 36 (68%) normal turnover osteoporosis (NTOP) as assessed by measurement of whole body retention (WBR) of 99mTc-methylene diphosphonate. The two groups did not differ in terms of bone mineral content (BMC) measured by dual photon absorptiometry at both lumbar spine and femoral diaphysis. However, HTOP patients had higher levels of serum osteocalcin (OC) and urinary hydroxyproline excretion (HOP/Cr). Multivariate regression analysis showed no correlation between parameters of bone turnover (WBR, OC, HOP/Cr) and both femoral and vertebral bone density; the latter being negatively correlated only with the years elapsed since menopause (R2 = 0.406). Treatment with sCT resulted in a significant increase of vertebral BMC in the 53 patients taken as a whole group (+/- 7%, P less than 0.001). When the results obtained in HTOP and NTOP were analyzed separately, only those with HTOP showed a marked increment of spinal BMC (+22%, P less than 0.001), NTOP subjects neither gained nor lost bone mineral during the study. Femoral BMC decreased in the whole group after sCT therapy (-3%, P less than 0.003). However, HTOP patients maintained initial BMC values, whereas those with NTOP lost a significant amount of bone during the study period (-5%, P less than 0.001). The increase of vertebral bone mass was associated with a marked depression of bone turnover detectable in both subsets of patients and in the whole group. In conclusion: (a) assessment of bone turnover cannot help predict the severity of bone loss in postmenopausal osteoporosis; (b) calcitonin therapy appears to be particularly indicated for patients with high-turnover osteoporosis, resulting in a net gain of bone mineral in the axial skeleton and a slowing of bone loss in the appendicular bones. PMID:3262626

Turnover intention and related factors among general practitioners in Hubei, China: a cross-sectional study.

PubMed

Gan, Yong; Gong, Yanhong; Chen, Yawen; Cao, Shiyi; Li, Liqing; Zhou, Yanfeng; Herath, Chulani; Li, Wenzhen; Song, Xingyue; Li, Jing; Yang, Tingting; Yin, Xiaoxv; Lu, Zuxun

2018-05-24

High turnover among general practitioners (GPs) is a significant challenge in China's efforts to build a sustainable, effective primary care system, but little data is available to help understand and address this issue. The study was aiming at assessing the intention to leave their posts among a sample of GPs and investigating associated factors. A cross-sectional survey was conducted between December 12, 2014 and March 10, 2015 in Hubei Province, Central China. A total of 1016 GPs (response rate, 85.67%) were investigated by using a structured self-administered questionnaire. A generalized linear regression model was used to identify the associated factors with turnover intention among GPs. Based on a full score of 24, the average score for GPs' turnover intention was 15.40 (SD = 3.43). 78.35% of the GPs had a moderate or higher level of turnover intention. Six hundred and thirty one (62.37%) GPs had ever been exposed to abuse of any kind (physical assault, 18.92%; verbal abuse, 54.38%; threat, 33.79%; verbal sexual harassment, 22.66%; and physical sexual harassment, 7.59%). Generalized linear regression analysis indicated that GPs who were male; who had a vocational school or higher; who had a temporary work contract; who were with lower level of job satisfaction; who reported higher scores on emotional exhaustion; who had been exposed to higher frequency of workplace violence were expressed higher intention to leave their present positions. This study shows that GP's intention to leave general practices is high in Hubei, China. In addition, the prevalence of workplace violence is high among GPs, particularly in the verbal abuse and threat. Measures such as offering permanent contract status, increasing overall job satisfaction, and improving doctor-patient relationship, are needed to moderate GP's turnover intention in order to maintain the foundation of China's three-tier health system.

Optimising antiresorptive therapies in postmenopausal women: why do we need to give due consideration to the degree of suppression?

PubMed

Karsdal, Morten A; Qvist, Per; Christiansen, Claus; Tankó, László B

2006-01-01

Accelerated bone turnover with bone resorption exceeding bone formation is a major mechanism underlying postmenopausal bone loss and hence the development of osteoporosis. Accordingly, inhibition of bone resorption is a rational approach for the prevention of osteoporosis. In this context, the most logical option, hormone replacement therapy, reverses the rate of bone turnover to premenopausal levels, whereas the magnitude of inhibition by amino-bisphosphonates and the recently introduced anti-receptor activator of NFkappaB ligand (RANKL) antibody often exceeds this. As bone turnover has crucial implications for the continuous renewal of bone tissue, the over-suppression of bone turnover has potential consequences for bone quality and strength. Long-term treatment with potent bisphosphonates has recently been associated with osteonecrosis of the jaw and dose-dependent increases in micro-crack accumulation in animals. Although these observations are the subject of ongoing discussions, it is timely to discuss whether the over-suppression of bone turnover below premenopausal levels is really our ultimate goal when defining the success criteria for antiresorptive agents. In this review, the implications of high and excessively low bone turnover of endogenous origin for bone quality, fracture risk and integrity of the jaw are discussed. In addition, animal and clinical research revealing initial findings regarding the potential adverse effects of drug-induced suppression of bone remodeling are summarised. The inhibition of bone resorption, which is either transient between doses (e.g. with calcitonin) or does not exceed premenopausal levels (with hormone replacement therapy or selective estrogen receptor modulators), is preferable because it not only provides similar antifracture efficacy but can also assist in the maintenance of the dynamic repair of micro-cracks/micro-fractures.

Gold nanoparticles stabilized by poly(4-vinylpyridine) grafted cellulose nanocrystals as efficient and recyclable catalysts.

PubMed

Zhang, Zhen; Sèbe, Gilles; Wang, Xiaosong; Tam, Kam C

2018-02-15

pH-responsive poly(4-vinylpyridine) (P4VP) grafted cellulose nanocrystals (P4VP-g-CNC) were prepared by Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) and subsequently used to stabilize gold nanoparticles (Au NPs) as efficient and recyclable nanocatalysts for the reduction of 4-nitrophenol (4NP). The presence of P4VP brushes on the CNC surface controlled the growth of Au NPs yielding smaller averaged diameter compared to Au NPs deposited directly on pristine CNC. The catalytic performances of pristine Au NPs, Au@CNC and Au@P4VP-g-CNC were compared by measuring the turnover frequency (TOF) for the catalytic reduction of 4NP. Compared to pristine Au NPs, the catalytic activity of Au@CNC and Au@P4VP-g-CNC were 10 and 24 times better. Moreover, the Au@P4VP-g-CNC material could be recovered via flocculation at pH>5, and the recycled nanocatalyst remained highly active. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigating the low-mass slope and possible turnover in the LMC IMF

NASA Astrophysics Data System (ADS)

Gennaro, Mario

2014-10-01

We propose to derive the Initial Mass Function (IMF) of the field population of the Large Magellanic Cloud (LMC) down to 0.2 solar masses, probing the mass regime where the characteristic IMF turnover is observed in our Galaxy. The power of the HST, using the WFC3 IR channel, is necessary to obtain photometric mass estimates for the faint, cool, dwarf stars with masses below the expected IMF turnover point. Only by probing the IMF down to such masses, it will be possible to clearly distinguish between a bottom-heavy or bottom-light IMF in the LMC. Recent studies, using the deepest available observations for the Small Magellanic Cloud, cannot find clear evidence of a turnover in the IMF for this galaxy, suggesting a bottom-heavy IMF in contrast to the Milky Way. A similar study of the LMC is needed to confirm a possible dependence of the low-mass IMF with galactic environment. Studies of giant ellipticals have recently challenged the picture of a universal IMF, and suggest an enviromental dependence of the IMF, with the most massive galaxies having a larger fraction of low mass stars and no IMF turnover. A study of possible IMF variations from resolved stellar populations in nearby galaxies is of great importance in sheding light on this issue. Our simple approach, using direct evidence from basic star counts, is much less prone to systematic errors with respect to studies of more distant objects which have to rely on the observations of integrated properties.

Effect of a hawthorn extract on contraction and energy turnover of isolated rat cardiomyocytes.

PubMed

Pöpping, S; Rose, H; Ionescu, I; Fischer, Y; Kammermeier, H

1995-11-01

The hawthorn extract LI 132 (crataegus), prepared from leaves and flowers, and standardised to 2.2% flavonoids, was investigated with respect to its effect on (1) the contraction, (2) the energy-turnover and (3) the apparent refractory period (t(ref)) of isolated cardiac myocytes from adult rats. (1) The contractile behaviour of attached myocytes was analyzed by an image processing system. (2) The energy turnover was calculated from the decrease in oxygen content in the myocyte suspension, brought about by cellular respiration. It was differentiated between energy turnover related to cell shortening and that required for ionic transport processes by application of the contraction-inhibiting agent 2,3-butanedione monoxime. (3) The apparent refractory period (t(ref)) was evaluated by pacing the myocytes with increasing stimulation rates and determining the frequency at which failure of single contractions occurred. For these purposes, the myocytes were incubated in a stimulation chamber, which is part of a computer-assisted system allowing to simultaneously evaluate the mechanics and energetics of electrically induced contraction. Within a range of 30-180 microg/ml, the hawthorn extract exhibited a positive inotropic effect on the contraction amplitude accompanied by a moderate increase of energy turnover both for mechanical and ionic processes. In comparison with other positive inotropic interventions, such as application of the beta-adrenergic agonist isoprenaline, or of the cardiac glycoside ouabain (g-strophantin), or elevation of the extracellular Ca++-concentration, the effects of the hawthorn extract were significantly more economical with respect to the energetics of the myocytes. Furthermore the extract prolonged the apparent refractory period in the presence and the absence of isoprenaline, which be indicative for an antiarrhythmic potential.

Interferometric Monitoring of Gamma-Ray Bright AGNs: S5 0716+714

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jee Won; Lee, Sang-Sung; Hodgson, Jeffrey A.

We present the results of very long baseline interferometry (VLBI) observations of gamma-ray bright blazar S5 0716+714 using the Korean VLBI Network (KVN) at the 22, 43, 86, and 129 GHz bands, as part of the Interferometric Monitoring of Gamma-ray Bright active galactic nuclei (iMOGABA) KVN key science program. Observations were conducted in 29 sessions from 2013 January 16 to 2016 March 1, with the source being detected and imaged at all available frequencies. In all epochs, the source was compact on the milliarcsecond scale, yielding a compact VLBI core dominating the synchrotron emission on these scales. Based on themore » multiwavelength data between 15 GHz (Owens Valley Radio Observatory) and 230 GHz (Submillimeter Array), we found that the source shows multiple prominent enhancements of the flux density at the centimeter (cm) and millimeter (mm) wavelengths, with mm enhancements leading cm enhancements by −16 ± 8 days. The turnover frequency was found to vary between 21 and 69 GHz during our observations. By assuming a synchrotron self-absorption model for the relativistic jet emission in S5 0716+714, we found the magnetic field strength in the mas emission region to be ≤5 mG during the observing period, yielding a weighted mean of 1.0 ± 0.6 mG for higher turnover frequencies (e.g., >45 GHz).« less

Hydrodeoxygenation of vicinal OH groups over heterogeneous rhenium catalyst promoted by palladium and ceria support.

PubMed

Ota, Nobuhiko; Tamura, Masazumi; Nakagawa, Yoshinao; Okumura, Kazu; Tomishige, Keiichi

2015-02-02

Heterogeneous ReOx-Pd/CeO2 catalyst showed excellent performance for simultaneous hydrodeoxygenation of vicinal OH groups. High yield (>99%), turnover frequency (300 h(-1)), and turnover number (10,000) are achieved in the reaction of 1,4-anhydroerythritol to tetrahydrofuran. This catalyst can be applied to sugar alcohols, and mono-alcohols and diols are obtained in high yields (≥85%) from substrates with even and odd numbers of OH groups, respectively. The high catalytic performance of ReOx-Pd/CeO2 can be assigned to rhenium species with +4 or +5 valence state, and the formation of this species is promoted by H2/Pd and the ceria support. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Specialized new graduate RN pediatric orientation: a strategy for nursing retention and its financial impact.

PubMed

Friedman, M Isabel; Delaney, Margaret M; Schmidt, Kathleen; Quinn, Carolyn; Macyk, Irene

2013-01-01

New graduate RN retention in the first year of employment is a challenge for hospitals, ranging from a low of 25% to a high of 64%. In 2005, hospitals in New York state spent 11.7% of their nursing budgets on temporary nursing staffing. The objectives of this study were to determine the retention and costs associated with the employment of new graduate RNs before and after the initiation of specialized year-long pediatric critical care, emergency department, and hematology/oncology orientation programs. The major study findings were improved retention of 84% to 94%, significant retention between the two groups at 9 months, and an annual financial savings related to decreased nursing turnover in the specialized orientation group. Specialized orientation programs that support new graduate RNs have documented increased RN retention and decreased RN turnover. In concert with the increased retention and decreased turnover, health care finances were positively impacted by specialized orientation programs.

Bone metabolism and arterial stiffness after renal transplantation.

PubMed

Cseprekál, Orsolya; Kis, Eva; Dégi, Arianna A; Kerti, Andrea; Szabó, Attila J; Reusz, György S

2014-01-01

To assess the relationship between bone and vascular disease and its changes over time after renal transplantation. Metabolic bone disease (MBD) is common in chronic kidney disease (CKD) and is associated with cardiovascular (CV) disease. Following transplantation (Tx), improvement in CV disease has been reported; however, data regarding changes in bone disease remain controversial. Bone turnover and arterial stiffness (pulse wave velocity (PWV)) were assessed in 47 Tx patients (38 (3-191) months after Tx). Bone alkaline phosphatase (BALP), osteocalcin (OC) and beta-crosslaps were significantly higher in Tx patients, and decreased significantly after one year. There was a negative correlation between BALP, OC and steroid administered (r = -0.35; r = -0.36 respectively). PWV increased in the Tx group (1.15 SD). In patients with a follow up of <24 months, PWV was correlated with BALP and beta-crosslaps (r=0.53; r = 0.69 respectively) while in the ≥24 months group, PWV was correlated with cholesterol (r=0.38). Increased bone turnover and arterial stiffness are present following kidney transplantation. While bone turnover decreases with time, arterial stiffness correlates initially with bone turnover, after which the influence of cholesterol becomes significant. Non-invasive estimation of bone metabolism and arterial stiffness may help to assess CKD-MBD following renal transplantation.

Stepping stones: Principal career paths and school outcomes.

PubMed

Béteille, Tara; Kalogrides, Demetra; Loeb, Susanna

2012-07-01

More than one out of every five principals leaves their school each year. In some cases, these career changes are driven by the choices of district leadership. In other cases, principals initiate the move, often demonstrating preferences to work in schools with higher achieving students from more advantaged socioeconomic backgrounds. Principals often use schools with many poor or low-achieving students as stepping stones to what they view as more desirable assignments. We use longitudinal data from one large urban school district to study the relationship between principal turnover and school outcomes. We find that principal turnover is, on average, detrimental to school performance. Frequent turnover of school leadership results in lower teacher retention and lower student achievement gains. Leadership changes are particularly harmful for high poverty schools, low-achieving schools, and schools with many inexperienced teachers. These schools not only suffer from high rates of principal turnover but are also unable to attract experienced successors. The negative effect of leadership changes can be mitigated when vacancies are filled by individuals with prior experience leading other schools. However, the majority of new principals in high poverty and low-performing schools lack prior leadership experience and leave when more attractive positions become available in other schools. Copyright © 2012 Elsevier Inc. All rights reserved.

Who is Leaving the Federal Government?

DTIC Science & Technology

1989-01-01

quality of worklife , offer alterna- tasks. tive employee benefits, or initiate some other changes The need for more information about Federal turnover in...Federal work force?2 A 1988 General serious personnel imbalances and a diminished ability Auting Offe tdeplitycl for an ngranto serve #he general public

TeamSTEPPS Improves Operating Room Efficiency and Patient Safety.

PubMed

Weld, Lancaster R; Stringer, Matthew T; Ebertowski, James S; Baumgartner, Timothy S; Kasprenski, Matthew C; Kelley, Jeremy C; Cho, Doug S; Tieva, Erwin A; Novak, Thomas E

2016-09-01

The objective was to evaluate the effect of TeamSTEPPS on operating room efficiency and patient safety. TeamSTEPPS consisted of briefings attended by all health care personnel assigned to the specific operating room to discuss issues unique to each case scheduled for that day. The operative times, on-time start rates, and turnover times of all cases performed by the urology service during the initial year with TeamSTEPPS were compared to the prior year. Patient safety issues identified during postoperative briefings were analyzed. The mean case time was 12.7 minutes less with TeamSTEPPS (P < .001). The on-time first-start rate improved by 21% with TeamSTEPPS (P < .001). The mean room turnover time did not change. Patient safety issues declined from an initial rate of 16% to 6% at midyear and remained stable (P < 0.001). TeamSTEPPS was associated with improved operating room efficiency and diminished patient safety issues in the operating room. © The Author(s) 2015.

One Electron-Initiated Two-Electron Oxidation of Water by Aluminum Porphyrins with Earth's Most Abundant Metal.

PubMed

Kuttassery, Fazalurahman; Mathew, Siby; Sagawa, Shogo; Remello, Sebastian Nybin; Thomas, Arun; Yamamoto, Daisuke; Onuki, Satomi; Nabetani, Yu; Tachibana, Hiroshi; Inoue, Haruo

2017-05-09

We report herein a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was detected by a cold-spray ionization mass-spectrometry in high-resolution MS (HRMS) mode and the structure of the intermediate species was further confirmed using laser Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction. The two-electron oxidation of water to form hydrogen peroxide was essentially quantitative, with a Faradaic efficiency of 99 %. The catalytic reaction was found to be highly efficient, with a turnover frequency up to ∼2×10 4  s -1 . A reaction mechanism is proposed involving oxygen-oxygen bond formation by the attack of a hydroxide ion on the oxyl-radical-like axial ligand oxygen atom in the one-electron-oxidized form of AlTMPyP(O - ) 2 , followed by a second electron transfer to the electrode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Requirements for rapid plasmid ColE1 copy number adjustments: a mathematical model of inhibition modes and RNA turnover rates.

PubMed

Paulsson, J; Nordström, K; Ehrenberg, M

1998-01-01

The random distribution of ColE1 plasmids between the daughter cells at cell division introduces large copy number variations. Statistic variation associated with limited copy number in single cells also causes fluctuations to emerge spontaneously during the cell cycle. Efficient replication control out of steady state is therefore important to tame such stochastic effects of small numbers. In the present model, the dynamic features of copy number control are divided into two parts: first, how sharply the replication frequency per plasmid responds to changes in the concentration of the plasmid-coded inhibitor, RNA I, and second, how tightly RNA I and plasmid concentrations are coupled. Single (hyperbolic)- and multiple (exponential)-step inhibition mechanisms are compared out of steady state and it is shown how the response in replication frequency depends on the mode of inhibition. For both mechanisms, sensitivity of inhibition is "bought" at the expense of a rapid turnover of a replication preprimer, RNA II. Conventional, single-step, inhibition kinetics gives a sloppy replication control even at high RNA II turnover rates, whereas multiple-step inhibition has the potential of working with unlimited precision. When plasmid concentration changes rapidly, RNA I must be degraded rapidly to be "up to date" with the change. Adjustment to steady state is drastically impaired when the turnover rate constants of RNA I decrease below certain thresholds, but is basically unaffected for a corresponding increase. Several features of copy number control that are shown to be crucial for the understanding of ColE1-type plasmids still remain to be experimentally characterized. It is shown how steady-state properties reflect dynamics at the heart of regulation and therefore can be used to discriminate between fundamentally different copy number control mechanisms. The experimental tests of the predictions made require carefully planned assays, and some suggestions for suitable experiments arise naturally from the present work. It is also discussed how the presence of the Rom protein may affect dynamic qualities of copy number control. Copyright 1998 Academic Press.

Design and application of sporopollenin microcapsule supported palladium catalyst: Remarkably high turnover frequency and reusability in catalysis of biaryls.

PubMed

Baran, Talat; Sargin, Idris; Kaya, Murat; Menteş, Ayfer; Ceter, Talip

2017-01-15

Bio-based catalyst support materials with high thermal and structural stability are desired for catalysts systems requiring harsh conditions. In this study, a thermally stable palladium catalyst (up to 440°C) was designed from sporopollenin, which occurs naturally in the outer exine layer of pollens and is widely acknowledged as chemically very stable and inert biological material. Catalyst design procedure included (1) extraction of sporopollenin microcapsules from Betula pendula pollens (∼25μm), (2) amino-functionalisation of the microcapsules, (3) Schiff base modification and (4) preparation of Pd(II) catalyst. The catalytic activity of the sporopollenin microcapsule supported palladium catalyst was tested in catalysis of biaryls by following a fast, simple and green microwave-assisted method. We recorded outstanding turnover number (TON: 40,000) and frequency (TOF: 400,000) for the catalyst in Suzuki coupling reactions. The catalyst proved to be reusable at least in eight cycles. The catalyst can be suggested for different catalyst systems due to its thermal and structural durability, reusability, inertness to air and its eco-friendly nature. Copyright © 2016 Elsevier Inc. All rights reserved.

Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis).

PubMed

McGee, Meghan E; Maki, Aaron J; Johnson, Steven E; Nelson, O Lynne; Robbins, Charles T; Donahue, Seth W

2008-02-01

Disuse uncouples bone formation from resorption, leading to increased porosity, decreased bone geometrical properties, and decreased bone mineral content which compromises bone mechanical properties and increases fracture risk. However, black bear bone properties are not adversely affected by aging despite annual periods of disuse (i.e., hibernation), which suggests that bears either prevent bone loss during disuse or lose bone and subsequently recover it at a faster rate than other animals. Here we show decreased cortical bone turnover during hibernation with balanced formation and resorption in grizzly bear femurs. Hibernating grizzly bear femurs were less porous and more mineralized, and did not demonstrate any changes in cortical bone geometry or whole bone mechanical properties compared to active grizzly bear femurs. The activation frequency of intracortical remodeling was 75% lower during hibernation than during periods of physical activity, but the normalized mineral apposition rate was unchanged. These data indicate that bone turnover decreases during hibernation, but osteons continue to refill at normal rates. There were no changes in regional variation of porosity, geometry, or remodeling indices in femurs from hibernating bears, indicating that hibernation did not preferentially affect one region of the cortex. Thus, grizzly bears prevent bone loss during disuse by decreasing bone turnover and maintaining balanced formation and resorption, which preserves bone structure and strength. These results support the idea that bears possess a biological mechanism to prevent disuse osteoporosis.

Vitamin D receptor genotypes are not associated with rheumatoid arthritis or biochemical parameters of bone turnover in German RA patients.

PubMed

Goertz, B; Fassbender, W J; Williams, J C; Marzeion, A M; Bretzel, R G; Stracke, H; Berliner, M N

2003-01-01

Vitamin D is known to exert immunomodulatory effects. An overrepresentation of the b allele of the vitamin D receptor (VDR) has been detected in autoimmune diseases as type-1-diabetes and multiple sclerosis. VDR polymorphisms have been shown to influence bone metabolism and bone density. The aim of the present study was to examine the distribution of VDR alleles in German rheumatoid arthritis (RA) patients and their relation to bone turnover parameters. 62 German RA patients were included and compared to 40 controls. Three VDR alleles were examined (Bsm I, Taq I and Fok I). In addition, serum intact osteocalcin (OC), parathyroid hormone, bone specific alkaline phosphatase (B-ALP), the carboxyterminal extension peptide of type I procollagen, 25-OH-vitamin D and urinary deoxypyridinoline (DPD) excretion were measured. Furthermore, C-reactive protein, erythrocyte sedimentation rate and rheumatoid factor were measured. We found a slightly higher frequency of the bB and tT-genotype in RA patients compared to controls, which was not statistically significant. OC and B-ALP were found to be significantly higher in RA patients with positive correlations between bone formation and resorption parameters indicating higher bone turnover in RA patients with maintained coupling. CRP in RA patients correlated with DPD and inversely with PTH. VDR genotype showed no association with bone turnover, family history or the presence of rheumatoid factor. Our results suggest that VDR polymorphisms do not play a major role in RA predisposition in Germans.

Improving operating room turnover time: a systems based approach.

PubMed

Bhatt, Ankeet S; Carlson, Grant W; Deckers, Peter J

2014-12-01

Operating room (OR) turnover time (TT) has a broad and significant impact on hospital administrators, providers, staff and patients. Our objective was to identify current problems in TT management and implement a consistent, reproducible process to reduce average TT and process variability. Initial observations of TT were made to document the existing process at a 511 bed, 24 OR, academic medical center. Three control groups, including one consisting of Orthopedic and Vascular Surgery, were used to limit potential confounders such as case acuity/duration and equipment needs. A redesigned process based on observed issues, focusing on a horizontally structured, systems-based approach has three major interventions: developing consistent criteria for OR readiness, utilizing parallel processing for patient and room readiness, and enhancing perioperative communication. Process redesign was implemented in Orthopedics and Vascular Surgery. Comparisons of mean and standard deviation of TT were made using an independent 2-tailed t-test. Using all surgical specialties as controls (n = 237), mean TT (hh:mm:ss) was reduced by 0:20:48 min (95 % CI, 0:10:46-0:30:50), from 0:44:23 to 0:23:25, a 46.9 % reduction. Standard deviation of TT was reduced by 0:10:32 min, from 0:16:24 to 0:05:52 and frequency of TT≥30 min was reduced from 72.5to 11.7 %. P < 0.001 for each. Using Vascular and Orthopedic surgical specialties as controls (n = 13), mean TT was reduced by 0:15:16 min (95 % CI, 0:07:18-0:23:14), from 0:38:51 to 0:23:35, a 39.4 % reduction. Standard deviation of TT reduced by 0:08:47, from 0:14:39 to 0:05:52 and frequency of TT≥30 min reduced from 69.2 to 11.7 %. P < 0.001 for each. Reductions in mean TT present major efficiency, quality improvement, and cost-reduction opportunities. An OR redesign process focusing on parallel processing and enhanced communication resulted in greater than 35 % reduction in TT. A systems-based focus should drive OR TT design.

Aerobic oxidations catalyzed by chromium corroles.

PubMed

Mahammed, Atif; Gray, Harry B; Meier-Callahan, Alexandre E; Gross, Zeev

2003-02-05

Oxochromium(V) complexes of 5,10,15-tris(pentafluorophenyl)corrole and brominated derivatives oxygenate substrates (triphenylphosphine and norbornene) with concomitant production of chromium(III). Regeneration of CrVO by reaction of dioxygen with CrIII completes an aerobic catalytic cycle, with very large solvent effects; in acetonitrile, rapid initial turnovers observed initially are shut down by formation of CrIVO, while in toluene, THF, and methanol, relatively slow reactions are further inhibited by product formation.

Wave-field decay rate estimate from the wavenumber-frequency spectra

NASA Astrophysics Data System (ADS)

Comisel, H.; Narita, Y.; Voros, Z.

2017-12-01

Observational data for wave or turbulent fields are conveniently analyzed and interpreted in the Fourier domain spanning the frequencies and the wavenumbers. If a wave field has not only oscillatory components (characterized by real parts of frequency) but also temporally decaying components (characterized by imaginary parts of frequency), the energy spectrum shows a frequency broadening around the peak due to the imaginary parts of frequency (or the decay rate). The mechanism of the frequency broadening is the same as that of the Breit-Wigner spectrum in nuclear resonance phenomena. We show that the decay rate can observationally and directly be estimated once multi-point data are available, and apply the method to Cluster four-point magnetometer data in the solar wind on a spatial scale of about 1000 km. The estimated decay rate is larger than the eddy turnover time, indicating that the decay profile of solar wind turbulence is more plasma physical such as excitation of whistler waves and other modes rather than hydrodynamic turbulence behavior.

Proceedings of the Annual Frequency Control Symposium (31st) Held at Atlantic City, New Jersey on 1-3 June 1977.

DTIC Science & Technology

1977-01-01

Frequency Control , pp. 1-4, eyT75. considered representative of the crystal. 5 J. Kusters and J. Leach, "Further Experimental Data Long term aging has also...earlier. The solid f_ curves represent experimental results averaged over a group of units, and also over a number of runs on each 0 0 24.5 90 -11.5...was determined by picking four from each experimental As a result, our current pr3ctice is to design for group that were the closest in turnover

Accumulation and turnover of carbon in organic and mineral soils of the BOREAS northern study area

USGS Publications Warehouse

Trumbore, S.E.; Harden, J.W.

1997-01-01

Rates of input, accumulation, and turnover of C differ markedly within soil profiles and in soils with different drainage in the BOREAS northern study area. Soil C storage increases from ???3 kg C m-2 in well-drained, sandy soils to greater than 100 kg C m-2 in wetlands. Two modes of C accumulation were observed in upland soil profiles. Large annual C inputs (0.06-0.1 kg C m-2 yr-1) and slow decomposition (turnover times of 6-250 years) lead to rapid C accumulation in regrowing surface moss and detrital layers following fire. Deep organic layers that have accumulated over the millennia since the initiation of soil development, and are located below the most recent charred horizon, show slower rates of input (0.015-0.03 kg C m-2 yr-1) and turnover (100-1600 years) and accumulate C about 10 times slower than surface detrital layers. Rates of C input to soils derived from C and 14C data were in accord with net primary production estimates, with highest rates of input (0.14-0.6 kg C m-2 yr-1) in wetlands. Turnover times for C in surface detrital layers were 6-15 years for well-drained sand soils that showed highest soil temperatures in summer, 30-40 years for wetlands, and 36-250 years for uplands with thick moss cover and black spruce trees. Long (>100 years) turnover times in upland black spruce/clay soils most likely reflect the influence of woody debris incorporated into detrital layers. Turnover times for deep organic and mineral layer C were controlled by drainage, with fastest turnover (80-130 years) in well-drained sand soils and slowest turnover (>3000 years) in wetlands. Total C accumulation rates, which account for C losses from both deep organic and surface detrital layers, are close to zero for sand/jack pine soils, 0.003-0.01 kg C m-2 yr-1 for moderately to poorly drained sites in mature forest stands, and 0.03 kg C m-2 yr-1 for a productive fen. Decomposition of organic matter more than several decades old accounts for 9-22% of total heterotrophic respiration at these sites. The rates of C accumulation derived here are decadal averages for specific stands and will vary as stands age or undergo disturbance. Extrapolation to larger regions and longer timescales, where burning offsets C gains in moss layers, will yield smaller rates of C storage.

Safeguarding Your Investment: Effective Orientation for New Employees.

ERIC Educational Resources Information Center

Weingart, Sandra J.; Kochan, Carol A.; Hedrich, Anne

1998-01-01

Discusses a successful new employee orientation program: welcomes the newcomer, provides necessary tools, support and information, and familiarizes the individual with the institution. Shows how this initial investment of time and effort yields more productive, happier workers and reduces staff turnover and benefits the institution in the…

A dual isotope approach to isolate soil carbon pools of different turnover times

DOE PAGES

Torn, M. S.; Kleber, M.; Zavaleta, E. S.; ...

2013-12-10

Soils are globally significant sources and sinks of atmospheric CO 2. Increasing the resolution of soil carbon turnover estimates is important for predicting the response of soil carbon cycling to environmental change. We show that soil carbon turnover times can be more finely resolved using a dual isotope label like the one provided by elevated CO 2 experiments that use fossil CO 2. We modeled each soil physical fraction as two pools with different turnover times using the atmospheric 14C bomb spike in combination with the label in 14C and 13C provided by an elevated CO 2 experiment in amore » California annual grassland. In sandstone and serpentine soils, the light fraction carbon was 21–54% fast cycling with 2–9 yr turnover, and 36–79% slow cycling with turnover slower than 100 yr. This validates model treatment of the light fraction as active and intermediate cycling carbon. The dense, mineral-associated fraction also had a very dynamic component, consisting of ~7% fast-cycling carbon and ~93% very slow cycling carbon. Similarly, half the microbial biomass carbon in the sandstone soil was more than 5 yr old, and 40% of the carbon respired by microbes had been fixed more than 5 yr ago. Resolving each density fraction into two pools revealed that only a small component of total soil carbon is responsible for most CO 2 efflux from these soils. In the sandstone soil, 11% of soil carbon contributes more than 90% of the annual CO 2 efflux. The fact that soil physical fractions, designed to isolate organic material of roughly homogeneous physico-chemical state, contain material of dramatically different turnover times is consistent with recent observations of rapid isotope incorporation into seemingly stable fractions and with emerging evidence for hot spots or micro-site variation of decomposition within the soil matrix. Predictions of soil carbon storage using a turnover time estimated with the assumption of a single pool per density fraction would greatly overestimate the near-term response to changes in productivity or decomposition rates. Therefore, these results suggest a slower initial change in soil carbon storage due to environmental change than has been assumed by simpler (one-pool) mass balance calculations.« less

Molecular molybdenum persulfide and related catalysts for generating hydrogen from water

DOEpatents

Long, Jeffrey R.; Chang, Christopher J.; Karunadasa, Hemamala I.; Majda, Marcin

2016-11-22

New metal persulfido compositions of matter are described. In one embodiment the metal is molybdenum and the metal persulfido complex mimics the structure and function of the triangular active edge site fragments of MoS.sub.2, a material that is the current industry standard for petroleum hydro desulfurization, as well as a promising low-cost alternative to platinum for electrocatalytic hydrogen production. This molecular [(PY5W.sub.2)MoS.sub.2].sup.x+ containing catalyst is capable of generating hydrogen from acidic-buffered water or even seawater at very low overpotentials at a turnover frequency rate in excess of 500 moles H.sub.2 per mole catalyst per second, with a turnover number (over a 20 hour period) of at least 19,000,000 moles H.sub.2 per mole of catalyst.

Molecular molybdenum persulfide and related catalysts for generating hydrogen from water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Jeffrey R.; Chang, Christopher J.; Karunadasa, Hemamala I.

New metal persulfido compositions of matter are described. In one embodiment the metal is molybdenum and the metal persulfido complex mimics the structure and function of the triangular active edge site fragments of MoS.sub.2, a material that is the current industry standard for petroleum hydro desulfurization, as well as a promising low-cost alternative to platinum for electrocatalytic hydrogen production. This molecular [(PY5W.sub.2)MoS.sub.2].sup.x+ containing catalyst is capable of generating hydrogen from acidic-buffered water or even seawater at very low overpotentials at a turnover frequency rate in excess of 500 moles H.sub.2 per mole catalyst per second, with a turnover number (overmore » a 20 hour period) of at least 19,000,000 moles H.sub.2 per mole of catalyst.« less

α-MHC MitoTimer mouse: In vivo mitochondrial turnover model reveals remarkable mitochondrial heterogeneity in the heart

PubMed Central

Stotland, Aleksandr; Gottlieb, Roberta A.

2016-01-01

In order to maintain an efficient, energy-producing network in the heart, dysfunctional mitochondria are cleared through the mechanism of autophagy, which is closely linked with mitochondrial biogenesis; these, together with fusion and fission comprise a crucial process known as mitochondrial turnover. Until recently, the lack of molecular tools and methods available to researchers has impeded in vivo investigations of turnover. To investigate the process at the level of a single mitochondrion, our laboratory has developed the MitoTimer protein. Timer is a mutant of DsRed fluorescent protein characterized by transition from green fluorescence to a more stable red conformation over 48 h, and its rate of maturation is stable under physiological conditions. We fused the Timer cDNA with the inner mitochondrial membrane signal sequence and placed it under the control of a cardiac-restricted promoter. This construct was used to create the alpha-MHC-MitoTimer mice. Surprisingly, initial analysis of the hearts from these mice demonstrated a high degree of heterogeneity in the ratio of red-to-green fluorescence of MitoTimer in cardiac tissue. Further, scattered solitary mitochondria within cardiomyocytes display a much higher red-to-green fluorescence (red-shifted) relative to other mitochondria in the cell, implying a block in import of newly synthesized MitoTimer likely due to lower membrane potential. These red-shifted mitochondria may represent older, senescent mitochondria. Concurrently, the cardiomyocytes also contain a subpopulation of mitochondria that display a lower red-to-green fluorescence (green-shifted) relative to other mitochondria, indicative of germinal mitochondria that are actively engaged in import of newly-synthesized mito-targeted proteins. These mitochondria can be isolated and sorted from the heart by flow cytometry for further analysis. Initial studies suggest that these mice represent an elegant tool for the investigation of mitochondrial turnover in the heart. PMID:26654779

[Effects of hyposalinity in Thalassia testudinum (Hydrocharitaceae) from Parque Nacional Morrocoy, Venezuela].

PubMed

Pérez, D; Galindo, L

2000-12-01

The year 1996 had a high pluviosity in Morrocoy National Park (western coastal zone, Venezuela) and low salinity in December 1996 affected the seagrass beds, dominated by Thalassia testudinum. Patches without T. testudinum were observed in localities of the park that used to have very dense populations of this plant. Sampling was done at Las Luisas to determine leaf productivity, turnover rate, short shoot density and relative biomass of plant sections, in order to compare with data obtained in September 1996, previous to the event. Green leaves, roots and rhizomes were the most affected parts. Mean green leaf biomass decreased in January and February 1997 to 5% of the plant's total biomass; mean root biomass decreased in March to 40% and mean rhi zome biomass decreased in February to 30%. The density of the active short shoots decreased to a minimum in February, but in April it reached a value similar to that of September 1996. The density of the inactive short shoots decreased to a minimum in March, and they dissappeared in April, matching the increasing density of the active short shoots between these two months. In February 1997, 56% of the inactive short shoots showed evidence of leaf initiation. In January 1997 the leaf productivity and turnover rate values (2.72 +/- 0.35 g/m2/d and 2.15% leaf DW/d) were similar to the annual mean previously determined from Las Luisas (2.35 +/- 0.72 g/m2/d and 1.96% leaf DW/d). Nevertheless, the values of productivity and turnover rate detected at Las Luisas in April 1997 (4.88 +/- 2.14 g/m2/d and 4.66% leaf DW/d) were higher than those values previously reported for this location. In response to the mortality episode, the leaf productivity and turnover rate of T. testudinum increased and the leaf initiation was activated in the inactive short shoots.

Variable frequency iteration MPPT for resonant power converters

DOEpatents

Zhang, Qian; Bataresh, Issa; Chen, Lin

2015-06-30

A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values.

Cross enyne metathesis of para-substituted styrenes: a kinetic study of enyne metathesis.

PubMed

Giessert, Anthony J; Diver, Steven T

2005-01-20

[Reaction: see text] The intermolecular enyne metathesis between alkynes and styrene derivatives was developed to study electronic effects in enyne metathesis. A Hammett plot for the overall reaction, catalyst initiation and vinyl carbene turnover was determined with the second generation Grubbs ruthenium carbene catalyst.

The Tides of Talent.

ERIC Educational Resources Information Center

Taylor, Craig R.

2003-01-01

Results of recent studies on why people leave or stay with an employer identified organizational, job, and leadership issues. Factors included job satisfaction, organizational climate, salary and benefits, loyalty, and anxiety about the economy and job market. Research showed three periods of highest risk of turnover: after the initial 30-60 days,…

Designing for Learning Engagement in Remote Communities: Narratives from North of Sixty

ERIC Educational Resources Information Center

Doering, Aaron; Henrickson, Jeni

2014-01-01

There are multiple challenges to designing learning experiences for schools in remote communities, including technology and infrastructure limitations, high teacher and administrator turnover, and conflicting interests between local culture and school curricula. In this paper, we offer a brief history of educational initiatives in remote Arctic…

Aqueous Biphasic Systems for the Synthesis of Formates by Catalytic CO2 Hydrogenation: Integrated Reaction and Catalyst Separation for CO2 -Scrubbing Solutions.

PubMed

Scott, Martin; Blas Molinos, Beatriz; Westhues, Christian; Franciò, Giancarlo; Leitner, Walter

2017-03-22

Aqueous biphasic systems were investigated for the production of formate-amine adducts by metal-catalyzed CO 2 hydrogenation, including typical scrubbing solutions as feedstocks. Different hydrophobic organic solvents and ionic liquids could be employed as the stationary phase for cis-[Ru(dppm) 2 Cl 2 ] (dppm=bis-diphenylphosphinomethane) as prototypical catalyst without any modification or tagging of the complex. The amines were found to partition between the two phases depending on their structure, whereas the formate-amine adducts were nearly quantitatively extracted into the aqueous phase, providing a favorable phase behavior for the envisaged integrated reaction/separation sequence. The solvent pair of methyl isobutyl carbinol (MIBC) and water led to the most practical and productive system and repeated use of the catalyst phase was demonstrated. The highest single batch activity with a TOF av of approximately 35 000 h -1 and an initial TOF of approximately 180 000 h -1 was achieved in the presence of NEt 3 . Owing to higher stability, the highest productivities were obtained with methyl diethanolamine (Aminosol CST 115) and monoethanolamine (MEA), which are used in commercial scale CO 2 -scrubbing processes. Saturated aqueous solutions (CO 2 overpressure 5-10 bar) of MEA could be converted into the corresponding formate adducts with average turnover frequencies up to 14×10 3  h -1 with an overall yield of 70 % based on the amine, corresponding to a total turnover number of 150 000 over eleven recycling experiments. This opens the possibility for integrated approaches to carbon capture and utilization. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Aqueous Biphasic Systems for the Synthesis of Formates by Catalytic CO2 Hydrogenation: Integrated Reaction and Catalyst Separation for CO2‐Scrubbing Solutions

PubMed Central

Scott, Martin; Blas Molinos, Beatriz; Westhues, Christian

2017-01-01

Abstract Aqueous biphasic systems were investigated for the production of formate–amine adducts by metal‐catalyzed CO2 hydrogenation, including typical scrubbing solutions as feedstocks. Different hydrophobic organic solvents and ionic liquids could be employed as the stationary phase for cis‐[Ru(dppm)2Cl2] (dppm=bis‐diphenylphosphinomethane) as prototypical catalyst without any modification or tagging of the complex. The amines were found to partition between the two phases depending on their structure, whereas the formate–amine adducts were nearly quantitatively extracted into the aqueous phase, providing a favorable phase behavior for the envisaged integrated reaction/separation sequence. The solvent pair of methyl isobutyl carbinol (MIBC) and water led to the most practical and productive system and repeated use of the catalyst phase was demonstrated. The highest single batch activity with a TOFav of approximately 35 000 h−1 and an initial TOF of approximately 180 000 h−1 was achieved in the presence of NEt3. Owing to higher stability, the highest productivities were obtained with methyl diethanolamine (Aminosol CST 115) and monoethanolamine (MEA), which are used in commercial scale CO2‐scrubbing processes. Saturated aqueous solutions (CO2 overpressure 5–10 bar) of MEA could be converted into the corresponding formate adducts with average turnover frequencies up to 14×103 h−1 with an overall yield of 70 % based on the amine, corresponding to a total turnover number of 150 000 over eleven recycling experiments. This opens the possibility for integrated approaches to carbon capture and utilization. PMID:28103428

Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.

PubMed

Torcasio, Antonia; Jähn, Katharina; Van Guyse, Maarten; Spaepen, Pieter; Tami, Andrea E; Vander Sloten, Jos; Stoddart, Martin J; van Lenthe, G Harry

2014-01-01

Exposure to microgravity causes loss of lower body bone mass in some astronauts. Low-magnitude high-frequency loading can stimulate bone formation on earth. Here we hypothesized that low-magnitude high-frequency loading will also stimulate bone formation under microgravity conditions. Two groups of six bovine cancellous bone explants were cultured at microgravity on a Russian Foton-M3 spacecraft and were either loaded dynamically using a sinusoidal curve or experienced only a static load. Comparable reference groups were investigated at normal gravity. Bone structure was assessed by histology, and mechanical competence was quantified using μCT and FE modelling; bone remodelling was assessed by fluorescent labelling and secreted bone turnover markers. Statistical analyses on morphometric parameters and apparent stiffness did not reveal significant differences between the treatment groups. The release of bone formation marker from the groups cultured at normal gravity increased significantly from the first to the second week of the experiment by 90.4% and 82.5% in response to static and dynamic loading, respectively. Bone resorption markers decreased significantly for the groups cultured at microgravity by 7.5% and 8.0% in response to static and dynamic loading, respectively. We found low strain magnitudes to drive bone turnover when applied at high frequency, and this to be valid at normal as well as at microgravity. In conclusion, we found the effect of mechanical loading on trabecular bone to be regulated mainly by an increase of bone formation at normal gravity and by a decrease in bone resorption at microgravity. Additional studies with extended experimental time and increased samples number appear necessary for a further understanding of the anabolic potential of dynamic loading on bone quality and mechanical competence.

High viral abundance as a consequence of low viral decay in the Baltic Sea redoxcline

PubMed Central

Scharnreitner, Lisa; Jürgens, Klaus; Labrenz, Matthias; Herndl, Gerhard J.; Winter, Christian

2017-01-01

Throughout the Baltic Sea redoxcline, virus production and the frequency of lytically-infected prokaryotic cells were estimated from parallel incubations of undiluted seawater and seawater that contained prokaryotes with substantially reduced numbers of viruses (virus dilution approach), effectively preventing viral reinfection during the incubation period. Undiluted seawater incubations resulted in much higher estimates of virus production (6–35×104 mL-1 h-1) and the frequency of infected cells (5–84%) than the virus dilution approach (virus production: 1–3×104 mL-1 h-1; frequency of infected cells: 1–11%). Viral production and the frequency of infected cells from both approaches, however, cannot be directly compared, as data obtained from undiluted incubations were biased by viral reinfection and other uncontrollable processes during the incubation period. High in situ viral abundance (1–2×107 mL-1) together with low virus production rates based on the virus dilution approach resulted in some of the longest viral turnover times (24–84 d) ever reported for the epipelagial. Throughout a wide range of environmental conditions, viral turnover time and burst size were negatively correlated. Given that viral decay estimated in ultra-filtered water was below the detection limit and the burst size was low (1–17), we conclude that prokaryotic viruses in the Baltic Sea redoxcline are investing most of their resources into stress defense (strong capsids) rather than proliferation (high burst size). In summary, the Baltic Sea redoxcline constitutes an environment where low virus production is found in combination with low viral decay, resulting in high viral abundance. PMID:28594863

Disentangling controls on mineral-stabilized soil organic matter using a slurry incubation

NASA Astrophysics Data System (ADS)

Lavallee, J. M.; Cotrufo, M. F.; Paul, E. A.; Conant, R. T.

2014-12-01

Mineral-stabilized organic matter (OM) is the largest and oldest pool of soil carbon and nitrogen. Mineral stabilization limits OM availability to soil microbes, preventing its decomposition and prolonging its turnover. Thus, understanding controls on the decomposition of mineral-stabilized OM is key to understanding soil carbon and nitrogen dynamics. The very slow turnover of mineral-stabilized OM makes it challenging to study in a typical incubation, and as a result, many potential controls (temperature, OM chemistry, and mineralogy) on its turnover remain unclear. We aimed to better understand controls on decomposition of mineral-stabilized OM by employing a slurry incubation technique, which speeds up microbial processing of OM by maximizing OM accessibility to microbes. In a slurry incubation, we expect that any OM that is not stabilized on mineral surfaces will be available for decomposition and will be converted to CO2. Using this technique, we studied the interactive effects of incubation temperature, plant material type (aboveground vs. belowground), and soil fraction (silt vs. clay) on CO2 efflux and OM stabilization. We separated silt-sized and clay-sized fractions from an agricultural soil, added aboveground or belowground plant material to each, and incubated them at 15°C, 25°C and 35°C. The added plant material was isotopically labeled (13C and 15N), which allowed us to trace it through the system and distinguish between the responses of the new (derived from the plant material) and old (derived from what was already present in the silt and clay) OM to warming. We measured CO2 efflux and 13CO2 efflux throughout the incubation. We performed one short-term harvest at day 6 and one final harvest at day 60. Initial results show higher cumulative CO2 efflux at warmer temperatures regardless of plant material type or soil fraction. A larger fraction of that CO2 came from OM that was initially present in the silt and clay, rather than from the plant material that we added, which suggests faster turnover of that "old" OM at warmer temperatures. We will present CO2 efflux data in addition to total [C] and [N] and the isotopic ratios of 13C and 15N in the silt and clay at each harvest to explain how the interactions between warming, plant material type and soil fraction affect turnover of mineral stabilized OM.

Long-term sensitivity of soil carbon turnover to warming.

PubMed

Knorr, W; Prentice, I C; House, J I; Holland, E A

2005-01-20

The sensitivity of soil carbon to warming is a major uncertainty in projections of carbon dioxide concentration and climate. Experimental studies overwhelmingly indicate increased soil organic carbon (SOC) decomposition at higher temperatures, resulting in increased carbon dioxide emissions from soils. However, recent findings have been cited as evidence against increased soil carbon emissions in a warmer world. In soil warming experiments, the initially increased carbon dioxide efflux returns to pre-warming rates within one to three years, and apparent carbon pool turnover times are insensitive to temperature. It has already been suggested that the apparent lack of temperature dependence could be an artefact due to neglecting the extreme heterogeneity of soil carbon, but no explicit model has yet been presented that can reconcile all the above findings. Here we present a simple three-pool model that partitions SOC into components with different intrinsic turnover rates. Using this model, we show that the results of all the soil-warming experiments are compatible with long-term temperature sensitivity of SOC turnover: they can be explained by rapid depletion of labile SOC combined with the negligible response of non-labile SOC on experimental timescales. Furthermore, we present evidence that non-labile SOC is more sensitive to temperature than labile SOC, implying that the long-term positive feedback of soil decomposition in a warming world may be even stronger than predicted by global models.

The evolutionary turnover of recombination hot spots contributes to speciation in mice.

PubMed

Smagulova, Fatima; Brick, Kevin; Pu, Yongmei; Camerini-Otero, R Daniel; Petukhova, Galina V

2016-02-01

Meiotic recombination is required for the segregation of homologous chromosomes and is essential for fertility. In most mammals, the DNA double-strand breaks (DSBs) that initiate meiotic recombination are directed to a subset of genomic loci (hot spots) by sequence-specific binding of the PRDM9 protein. Rapid evolution of the DNA-binding specificity of PRDM9 and gradual erosion of PRDM9-binding sites by gene conversion will alter the recombination landscape over time. To better understand the evolutionary turnover of recombination hot spots and its consequences, we mapped DSB hot spots in four major subspecies of Mus musculus with different Prdm9 alleles and in their F1 hybrids. We found that hot spot erosion governs the preferential usage of some Prdm9 alleles over others in hybrid mice and increases sequence diversity specifically at hot spots that become active in the hybrids. As crossovers are disfavored at such hot spots, we propose that sequence divergence generated by hot spot turnover may create an impediment for recombination in hybrids, potentially leading to reduced fertility and, eventually, speciation. Published by Cold Spring Harbor Laboratory Press.

The evolutionary turnover of recombination hot spots contributes to speciation in mice

PubMed Central

Smagulova, Fatima; Brick, Kevin; Pu, Yongmei; Camerini-Otero, R. Daniel; Petukhova, Galina V.

2016-01-01

Meiotic recombination is required for the segregation of homologous chromosomes and is essential for fertility. In most mammals, the DNA double-strand breaks (DSBs) that initiate meiotic recombination are directed to a subset of genomic loci (hot spots) by sequence-specific binding of the PRDM9 protein. Rapid evolution of the DNA-binding specificity of PRDM9 and gradual erosion of PRDM9-binding sites by gene conversion will alter the recombination landscape over time. To better understand the evolutionary turnover of recombination hot spots and its consequences, we mapped DSB hot spots in four major subspecies of Mus musculus with different Prdm9 alleles and in their F1 hybrids. We found that hot spot erosion governs the preferential usage of some Prdm9 alleles over others in hybrid mice and increases sequence diversity specifically at hot spots that become active in the hybrids. As crossovers are disfavored at such hot spots, we propose that sequence divergence generated by hot spot turnover may create an impediment for recombination in hybrids, potentially leading to reduced fertility and, eventually, speciation. PMID:26833728

High bone turnover elevates the risk of denosumab-induced hypocalcemia in women with postmenopausal osteoporosis

PubMed Central

Ishikawa, Koji; Nagai, Takashi; Sakamoto, Keizo; Ohara, Kenji; Eguro, Takeshi; Ito, Hiroshi; Toyoshima, Yoichi; Kokaze, Akatsuki; Toyone, Tomoaki; Inagaki, Katsunori

2016-01-01

Hypocalcemia is the most common major adverse event in patients with osteoporosis receiving the bone resorption inhibitor denosumab; however, limited information is available regarding risk factors of hypocalcemia. Therefore, this study aimed to identify the risk factors of hypocalcemia induced by denosumab treatment for osteoporosis. We retrospectively reviewed the records of patients who had received initial denosumab supplemented with activated vitamin D for osteoporosis. Serum levels of the following bone turnover markers (BTMs) were measured at baseline: bone-specific alkaline phosphatase (BAP), total N-terminal propeptide of type 1 procollagen (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and urinary cross-linked N-telopeptide of type 1 collagen (NTX). Of the 85 denosumab-treated patients with osteoporosis studied, 22 (25.9%) developed hypocalcemia. Baseline serum total P1NP, TRACP-5b, and urinary NTX were significantly higher in patients with hypocalcemia than in those with normocalcemia following denosumab administration (all P<0.01). Multivariate logistic regression analysis revealed that patients with total P1NP >76.5 μg/L, TRACP-5b >474 mU/dL, or urinary NTX >49.5 nmol bone collagen equivalent/mmol creatinine had a higher risk of hypocalcemia (P<0.01). Our study suggests that denosumab may have a greater impact on serum calcium levels in patients with postmenopausal osteoporosis with higher baseline bone turnover than in patients with postmenopausal osteoporosis with normal baseline bone turnover, because maintenance of normal serum calcium in this subgroup is more dependent on bone resorption. Close monitoring of serum calcium levels is strongly recommended for denosumab-treated patients with high bone turnover, despite supplementation with activated vitamin D and oral calcium. PMID:27980413

Impact of bone turnover markers and/or educational information on persistence to oral bisphosphonate therapy: a community setting-based trial.

PubMed

Silverman, S L; Nasser, K; Nattrass, S; Drinkwater, B

2012-03-01

We examined how the use of bone turnover markers and educational information affects persistence of bisphosphonate use in osteoporotic patients. We found that reporting bone turnover results and/or educational information did not affect persistence. Long-term adherence and persistence to osteoporosis medication are poor. We examined whether reporting of bone turnover marker results, education about osteoporosis, or a combination of both would increase persistence to oral bisphosphonates. Two hundred and forty women who were 5 years postmenopausal with BMD at least 2.0 standard deviations below normal were recruited for the study. All women were given a new prescription for alendronate and randomly assigned to one of four groups: (1) bone marker results at baseline, 3 and 12 months; (2) educational materials every month and a membership in the National Osteoporosis Foundation; (3) bone marker and educational information; and (4) control, no information other than usual care. Persistence among randomization groups was tested using survival analysis adjusting for the delay between intervention methods. Of those filling their initial prescription, 95.5% refilled their prescription at the end of the first month, 87% at 3 months, 82% at 6 months, and 78% at 10 months. Overall persistence through 12 months was 54%. There was no difference found among the four groups for persistence time using (p > 0.58). Providing bone turnover marker results is not an effective way to enhance early compliance and persistence with drug therapy. While the women in our study felt that bone marker results and educational information were helpful to them, there was no difference in persistence between those who received either bone marker information and/or educational information and those who did not. Because of the unexpected rate of primary nonadherence, this study may be underpowered.

Microaneurysm turnover is a predictor of diabetic retinopathy progression.

PubMed

Pappuru, Rajeev K R; Ribeiro, Luísa; Lobo, Conceição; Alves, Dalila; Cunha-Vaz, José

2018-04-26

To analyse retinopathy phenotypes and microaneurysm (MA) turnover in mild non-proliferative diabetic retinopathy (NPDR) as predictors of progression to diabetic central-involved macular oedema (CIMO) in patients with type 2 diabetes mellitus (DM) in two different ethnic populations. 205 patients with type 2 DM and mild NPDR were followed in a prospective observational study for 2 years or until development of CIMO, in two centres from different regions of the world. Ophthalmological examinations, including best-corrected visual acuity (BCVA), fundus photography with RetmarkerDR analysis, and optical coherence tomography (OCT), were performed at baseline and 6 12 and 24 months. 158 eyes/patients reached either the study endpoint, CIMO (24) or performed the last study visit (24-month visit) without developing CIMO (134). From the eyes/patients in analysis, 27 eyes (17.1%) progressed to more advanced ETDRS (Early Treatment Diabetic Retinopathy Study) levels: 6 progressed to mild NPDR (level 35), 15 progressed to moderate NPDR (level 43), 5 progressed to moderately severe NPDR (level 47) and 1 progressed to high risk PDR (level 71). Worsening in ETDRS level is associated with phenotype C (p=0.005). From the 130 eyes/patients with a low MA turnover, 18 (13.8%) eyes/patients had an increase in ETDRS level, and from the 19 eyes/patients with a high MA turnover, 9 (47.4%) had an increase in ETDRS level (p<0.001). Eyes in the initial stages of diabetic retinopathy show different phenotypes with different risks for progression to CIMO. In phenotype C, MA turnover correlates with ETDRS grading worsening and development of CIMO. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effects of immobilization and whole-body vibration on rat serum Type I collagen turnover.

PubMed

Dönmez, Gürhan; Doral, Mahmut Nedim; Suljevic, Şenay; Sargon, Mustafa Fevzi; Bilgili, Hasan; Demirel, Haydar Ali

2016-08-01

The aim of this study was to investigate the effects of short-term, high-magnitude whole-body vibration (WBV) on serum type I collagen turnover in immobilized rats. Thirty Wistar albino rats were randomly divided into the following 5 groups: immobilization (IS), immobilization + remobilization (IR), immobilization + WBV (IV), control (C), and WBV control (CV). Immobilization was achieved by casting from the crista iliaca anterior superior to the lower part of the foot for 2 weeks. The applied WBV protocol involved a frequency of 45 Hz and amplitude of 3 mm for 7 days starting a day after the end of the immobilization period. Serum type I collagen turnover markers were measured by using ELISA kits. Serum NH2-terminal propeptide of type I collagen (PINP) levels were significantly lower in the immobilization groups (p < 0.02) compared with the control groups. Although WBV improved PINP levels in the control groups, there were no differences in PINP levels among the immobilization groups. Similarly, serum COOH-terminal telopeptide of type I collagen (CTX) levels were higher in the WBV controls than their own controls (p < 0,05). Immobilization led to deterioration of tendon tissue, as observed by histopathological analysis with a transmission electron microscope. Although 1 week of WBV had a positive effect on type I collagen turnover in controls, it is not an efficient method for repairing tissue damage in the early stage following immobilization. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

A Highly Selective and Robust Co(II)-Based Homogeneous Catalyst for Reduction of CO2 to CO in CH3CN/H2O Solution Driven by Visible Light.

PubMed

Ouyang, Ting; Hou, Cheng; Wang, Jia-Wei; Liu, Wen-Ju; Zhong, Di-Chang; Ke, Zhuo-Feng; Lu, Tong-Bu

2017-07-03

Visible-light driven reduction of CO 2 into chemical fuels has attracted enormous interest in the production of sustainable energy and reversal of the global warming trend. The main challenge in this field is the development of efficient, selective, and economic photocatalysts. Herein, we report a Co(II)-based homogeneous catalyst, [Co(NTB)CH 3 CN](ClO 4 ) 2 (1, NTB = tris(benzimidazolyl-2-methyl)amine), which shows high selectivity and stability for the catalytic reduction of CO 2 to CO in a water-containing system driven by visible light, with turnover number (TON) and turnover frequency (TOF) values of 1179 and 0.032 s -1 , respectively, and selectivity to CO of 97%. The high catalytic activity of 1 for photochemical CO 2 -to-CO conversion is supported by the results of electrochemical investigations and DFT calculations.

Bone anabolics in osteoporosis: Actuality and perspectives

PubMed Central

Montagnani, Andrea

2014-01-01

Vertebral and nonvertebral fractures prevention is the main goal for osteoporosis therapy by inhibiting bone resorption and/or stimulating bone formation. Antiresorptive drugs decrease the activation frequency, thereby determining a secondary decrease in bone formation rate and a low bone turnover. Bisphosphonates are today’s mainstay among antiresorptive treatment of osteoporosis. Also, oral selective estrogen receptor modulators and recently denosumab have a negative effect on bone turnover. Agents active on bone formation are considered a better perspective in the treatment of severe osteoporosis. Recombinant-human parathyroid hormone (PTH) has showed to increase bone formation and significantly decrease vertebral fractures in severe patients, but with a modest effect on nonvertebral fractures. The study of Wnt signaling pathway, that induces prevalently an osteoblastic activity, opens large possibilities to antagonists of Wnt-inhibitors, such as sclerostin antibodies and dickkopf-1 antagonists, with potential effects not only on trabecular bone but also on cortical bone. PMID:25035827

Iridium Complexes with Proton-Responsive Azole-Type Ligands as Effective Catalysts for CO2 Hydrogenation.

PubMed

Suna, Yuki; Himeda, Yuichiro; Fujita, Etsuko; Muckerman, James T; Ertem, Mehmed Z

2017-11-23

Pentamethylcyclopentadienyl iridium (Cp*Ir) complexes with bidentate ligands consisting of a pyridine ring and an electron-rich diazole ring were prepared. Their catalytic activity toward CO 2 hydrogenation in 2.0 m KHCO 3 aqueous solutions (pH 8.5) at 50 °C, under 1.0 MPa CO 2 /H 2 (1:1) have been reported as an alternative to photo- and electrochemical CO 2 reduction. Bidentate ligands incorporating an electron-rich diazole ring improved the catalytic performance of the Ir complexes compared to the bipyridine ligand. Complexes 2, 4, and 6, possessing both a hydroxy group and an uncoordinated NH group, which are proton-responsive and capable of generating pendent bases in basic media, recorded high initial turnover frequency values of 1300, 1550, and 2000 h -1 , respectively. Spectroscopic and computational investigations revealed that the reversible deprotonation changes the electronic properties of the complexes and causes interactions between pendent base and substrate and/or solvent water molecules, resulting in high catalytic performance in basic media. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Origins of Better Jobs Better Care

ERIC Educational Resources Information Center

Stone, Robyn I.; Dawson, Steven L.

2008-01-01

Better Jobs Better Care was the nation's largest single initiative created to reduce the high vacancy and turnover rates of direct care workers and improve workforce quality through both policy and practice changes. In this article, we describe the important role and key characteristics of direct care workers, what motivated the unique partnership…

Caring for Caregivers: Addressing the Employment Needs of Long Term Care Workers. A Report.

ERIC Educational Resources Information Center

Loeb, Laura E.

Research confirms anecdotal impressions of the following causes of high turnover among both home health and nursing home aides: low wages; inadequate benefits; excessive workloads; poor training, supervision, and working conditions; and job-related stress. Public policy initiatives can dramatically alleviate or exacerbate the crisis among…

Assessment of bone metabolism in premenopausal females with hyperthyroidism and hypothyroidism.

PubMed

Tuchendler, Dominika; Bolanowski, Marek

2013-01-01

Osteoporosis is one of the commonest metabolic diseases of bone. Its possible causes may include thyroid hormonal dysfunction. The objective of this study was to evaluate the effects of hyperthyroidism and hypothyroidism on osseous tissue metabolism in premenopausal women. 38 women with hyperthyroidism, 40 with hypothyroidism and 41 healthy women participated in this study. Initially after 6 and 12 months, each patient underwent selected hormonal, immunological and biochemical tests, measurement of concentrations of bone turnover markers and densitometry were also performed. On initial evaluation, lower cortical bone density was found in patients with hyperthyroidism (femoral neck). After 12 months, an increase in BMD was seen, but it was still lower than in the control group. Statistically significantly higher concentrations of bone turnover markers, decreasing from the sixth month of treatment, were noted only in the group with hyperthyroidism. Statistically significant differences were not noted in the femoral neck nor in the lumbar spine BMD in patients with hypothyroidism. Hyperthyroidism poses a negative effect on bone metabolism. Hypothyroidism in premenopausal females does not have any influence on bone density.

Immobilization of a molecular catalyst on carbon nanotubes for highly efficient electro-catalytic water oxidation.

PubMed

Li, Fusheng; Li, Lin; Tong, Lianpeng; Daniel, Quentin; Göthelid, Mats; Sun, Licheng

2014-11-21

Electrochemically driven water oxidation has been performed using a molecular water oxidation catalyst immobilized on hybrid carbon nanotubes and nano-material electrodes. A high turnover frequency (TOF) of 7.6 s(-1) together with a high catalytic current density of 2.2 mA cm(-2) was successfully obtained at an overpotential of 480 mV after 1 h of bulk electrolysis.

OBSERVATIONS OF ROTATING RADIO TRANSIENTS WITH THE FIRST STATION OF THE LONG WAVELENGTH ARRAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, G. B.; Stovall, K.; McCrackan, M.

2016-11-10

Rotating radio transients (RRATs) are a subclass of pulsars first identified in 2006 that are detected only in searches for single pulses and not through their time averaged emission. Here, we present the results of observations of 19 RRATs using the first station of the Long Wavelength Array (LWA1) at frequencies between 30 and 88 MHz. The RRATs observed here were first detected in higher frequency pulsar surveys. Of the 19 RRATs observed, two sources were detected and their dispersion measures, periods, pulse profiles, and flux densities are reported and compared to previous higher frequency measurements. We find a lowmore » detection rate (11%), which could be a combination of the lower sensitivity of LWA1 compared to higher frequency telescopes, and the result of scattering by the interstellar medium or a spectral turnover.« less

Theoretical scaling law of coronal magnetic field and electron power-law index in solar microwave burst sources

NASA Astrophysics Data System (ADS)

Huang, Y.; Song, Q. W.; Tan, B. L.

2018-04-01

It is first proposed a theoretical scaling law respectively for the coronal magnetic field strength B and electron power-law index δ versus frequency and coronal height in solar microwave burst sources. Based on the non-thermal gyro-synchrotron radiation model (Ramaty in Astrophys. J. 158:753, 1969), B and δ are uniquely solved by the observable optically-thin spectral index and turnover (peak) frequency, the other parameters (plasma density, temperature, view angle, low and high energy cutoffs, etc.) are relatively insensitive to the calculations, thus taken as some typical values. Both of B and δ increase with increasing of radio frequency but with decreasing of coronal height above photosphere, and well satisfy a square or cubic logarithmic fitting.

Heterogeneous Single-Atom Catalyst for Visible-Light-Driven High-Turnover CO2 Reduction: The Role of Electron Transfer.

PubMed

Gao, Chao; Chen, Shuangming; Wang, Ying; Wang, Jiawen; Zheng, Xusheng; Zhu, Junfa; Song, Li; Zhang, Wenkai; Xiong, Yujie

2018-03-01

Visible-light-driven conversion of CO 2 into chemical fuels is an intriguing approach to address the energy and environmental challenges. In principle, light harvesting and catalytic reactions can be both optimized by combining the merits of homogeneous and heterogeneous photocatalysts; however, the efficiency of charge transfer between light absorbers and catalytic sites is often too low to limit the overall photocatalytic performance. In this communication, it is reported that the single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO 2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. As a result, the turnover number for CO production reaches a high value of 678 with an unprecedented turnover frequency of 3.77 min -1 , superior to those obtained with the state-of-the-art heterogeneous photocatalysts. This work provides fresh insights into the design of catalytic sites toward photocatalytic CO 2 conversion from the angle of single-atom catalysis and highlights the role of charge kinetics in bridging the gap between heterogeneous and homogeneous photocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Turnover of microbial groups and cell components in soil: 13C analysis of cellular biomarkers

NASA Astrophysics Data System (ADS)

Gunina, Anna; Dippold, Michaela; Glaser, Bruno; Kuzyakov, Yakov

2017-01-01

Microorganisms regulate the carbon (C) cycle in soil, controlling the utilization and recycling of organic substances. To reveal the contribution of particular microbial groups to C utilization and turnover within the microbial cells, the fate of 13C-labelled glucose was studied under field conditions. Glucose-derived 13C was traced in cytosol, amino sugars and phospholipid fatty acid (PLFA) pools at intervals of 3, 10 and 50 days after glucose addition into the soil. 13C enrichment in PLFAs ( ˜ 1.5 % of PLFA C at day 3) was an order of magnitude greater than in cytosol, showing the importance of cell membranes for initial C utilization. The 13C enrichment in amino sugars of living microorganisms at day 3 accounted for 0.57 % of total C pool; as a result, we infer that the replacement of C in cell wall components is 3 times slower than that of cell membranes. The C turnover time in the cytosol (150 days) was 3 times longer than in PLFAs (47 days). Consequently, even though the cytosol pool has the fastest processing rates compared to other cellular compartments, intensive recycling of components here leads to a long C turnover time. Both PLFA and amino-sugar profiles indicated that bacteria dominated in glucose utilization. 13C enrichment decreased with time for bacterial cell membrane components, but it remained constant or even increased for filamentous microorganisms. 13C enrichment of muramic acid was the 3.5 times greater than for galactosamine, showing a more rapid turnover of bacterial cell wall components compared to fungal. Thus, bacteria utilize a greater proportion of low-molecular-weight organic substances, whereas filamentous microorganisms are responsible for further C transformations. Thus, tracing 13C in cellular compounds with contrasting turnover rates elucidated the role of microbial groups and their cellular compartments in C utilization and recycling in soil. The results also reflect that microbial C turnover is not restricted to the death or growth of new cells. Indeed, even within living cells, highly polymeric cell compounds are constantly replaced and renewed. This is especially important for assessing C fluxes in soil and the contribution of C from microbial residues to soil organic matter.

Turn-over rate of academic faculty at the College of Health Sciences, Addis Ababa University: a 20-year analysis (1991 to 2011).

PubMed

Hailu, Alemayehu; Mariam, Damen Haile; Fekade, Daniel; Derbew, Miliard; Mekasha, Amha

2013-12-01

Faculty turn-over affects both workers and organizations. Turnover of faculty and researchers is increasing alarmingly and costing the universities and the country at large. Fast turnover of health professionals from the health system and from academic institutions has recently received substantial attention from both academia and health sector managers. This paper calculates the faculty turnover rate at the College of Health Sciences of Addis Ababa University during the period of September 1991 to August 2011. The study was conducted at the College of Health Sciences, Addis Ababa University. Retrospective analysis of employee records was done. All records of the faculty that were working in the College during the 20-year period, starting from September 1991 to August 2011 were retrospectively reviewed. Data were collected from the employee records accessed from the College's human resources database and supplemented by payroll sheets and different reports. A structured checklist was used to extract the required data from the database. The crude turnover rate for academic faculty was calculated. Within the 20-year period of September 1991 to August 2011, a total of 120 faculty members left. The overall turn-over rate was 92.8 %. The rate in the most recent five years (172 %) is 8.5 times higher than the rate for the first five years (20 %). The average retention period before the termination of an employment contract was 4.9 years. The top five departments where employment contracts were relatively higher include: Nursing 15 (15.6 %), Internal Medicine 12 (12.5%), Public Health 10 (10.4%), Pediatrics 9 (9.4%) and Surgery 9 (9.4%). About two thirds (66.6%) of the faculty who were leaving were at the ranks of assistant professorship and above. This study revealed that outflow of faculty has been continuously increasing in the period reviewed. This implies that the College had been losing highly skilled professionals with considerably higher costs in monetary terms. In this regard, an urgent response is required to retain or significantly decrease the outflow of faculty. Different motivation and retention mechanisms should be identified and implemented. Various modalities of faculty development programs should also be initiated.

Effect of ion concentration changes in the limited extracellular spaces on sarcolemmal ion transport and Ca2+ turnover in a model of human ventricular cardiomyocyte.

PubMed

Hrabcová, Dana; Pásek, Michal; Šimurda, Jiří; Christé, Georges

2013-12-13

We have developed a computer model of human cardiac ventricular myocyte (CVM), including t-tubular and cleft spaces with the aim of evaluating the impact of accumulation-depletion of ions in restricted extracellular spaces on transmembrane ion transport and ionic homeostasis in human CVM. The model was based on available data from human CVMs. Under steady state, the effect of ion concentration changes in extracellular spaces on [Ca2+]i-transient was explored as a function of critical fractions of ion transporters in t-tubular membrane (not documented for human CVM). Depletion of Ca2+ and accumulation of K+ occurring in extracellular spaces slightly affected the transmembrane Ca2+ flux, but not the action potential duration (APD90). The [Ca2+]i-transient was reduced (by 2%-9%), depending on the stimulation frequency, the rate of ion exchange between t-tubules and clefts and fractions of ion-transfer proteins in the t-tubular membrane. Under non-steady state, the responses of the model to changes of stimulation frequency were analyzed. A sudden increase of frequency (1-2.5 Hz) caused a temporal decrease of [Ca2+] in both extracellular spaces, a reduction of [Ca2+]i-transient (by 15%) and APD90 (by 13 ms). The results reveal different effects of activity-related ion concentration changes in human cardiac t-tubules (steady-state effects) and intercellular clefts (transient effects) in the modulation of membrane ion transport and Ca2+ turnover.

Productivity and turnover in PCPs: the role of staff participation in decision-making.

PubMed

Hung, Dorothy Y; Rundall, Thomas G; Cohen, Deborah J; Tallia, Alfred F; Crabtree, Benjamin F

2006-10-01

Efforts to redesign primary care practices are beginning to address how decisions are made in the practice setting. This study contributes to these efforts by examining associations between staff participation in decision-making, productivity, and turnover in primary care practices. The study is informed by organizational theories of participation that emphasize cognitive and affective influences on employee output and behavior. This research used data collected from primary care practices involved in a national initiative sponsored by the Robert Wood Johnson Foundation. Cross-sectional survey data on organizational structures and attributes among 49 practices were analyzed. Regression analysis was used to examine associations among practice productivity, staff participation in decision-making, and formal structures such as staff meetings. Associations between staff turnover and participative decision-making were also examined. Staff participation in decisions regarding quality improvement, practice change, and clinical operations was positively associated with practice productivity, whereas formal structures such as staff meetings were not. In addition, higher levels of participation in decision-making were associated with reduced turnover among nonclinicians and administrative staff. Examination of organizational features is increasingly recognized as a key to improving primary care performance. Study findings suggest that one important strategy may be implementation of a participative model emphasizing greater staff involvement in practice decisions. This may enhance information-sharing, work satisfaction, and commitment to organizational decisions, all of which can lead to beneficial outcomes such as increased productivity and stability in primary care practices.

Broadband Spectral Modeling of the Extreme Gigahertz-peaked Spectrum Radio Source PKS B0008-421

NASA Astrophysics Data System (ADS)

Callingham, J. R.; Gaensler, B. M.; Ekers, R. D.; Tingay, S. J.; Wayth, R. B.; Morgan, J.; Bernardi, G.; Bell, M. E.; Bhat, R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Ewall-Wice, A.; Feng, L.; Greenhill, L. J.; Hazelton, B. J.; Hindson, L.; Hurley-Walker, N.; Jacobs, D. C.; Johnston-Hollitt, M.; Kaplan, D. L.; Kudrayvtseva, N.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Srivani, K. S.; Subrahmanyan, R.; Udaya Shankar, N.; Webster, R. L.; Williams, A.; Williams, C. L.

2015-08-01

We present broadband observations and spectral modeling of PKS B0008-421 and identify it as an extreme gigahertz-peaked spectrum (GPS) source. PKS B0008-421 is characterized by the steepest known spectral slope below the turnover, close to the theoretical limit of synchrotron self-absorption, and the smallest known spectral width of any GPS source. Spectral coverage of the source spans from 0.118 to 22 GHz, which includes data from the Murchison Widefield Array and the wide bandpass receivers on the Australia Telescope Compact Array. We have implemented a Bayesian inference model fitting routine to fit the data with internal free-free absorption (FFA), single- and double-component FFA in an external homogeneous medium, FFA in an external inhomogeneous medium, or single- and double-component synchrotron self-absorption models, all with and without a high-frequency exponential break. We find that without the inclusion of a high-frequency break these models cannot accurately fit the data, with significant deviations above and below the peak in the radio spectrum. The addition of a high-frequency break provides acceptable spectral fits for the inhomogeneous FFA and double-component synchrotron self-absorption models, with the inhomogeneous FFA model statistically favored. The requirement of a high-frequency spectral break implies that the source has ceased injecting fresh particles. Additional support for the inhomogeneous FFA model as being responsible for the turnover in the spectrum is given by the consistency between the physical parameters derived from the model fit and the implications of the exponential spectral break, such as the necessity of the source being surrounded by a dense ambient medium to maintain the peak frequency near the gigahertz region. This implies that PKS B0008-421 should display an internal H i column density greater than 1020 cm-2. The discovery of PKS B0008-421 suggests that the next generation of low radio frequency surveys could reveal a large population of GPS sources that have ceased activity, and that a portion of the ultra-steep-spectrum source population could be composed of these GPS sources in a relic phase.

Carbon nanotube-supported Au-Pd alloy with cooperative effect of metal nanoparticles and organic ketone/quinone groups as a highly efficient catalyst for aerobic oxidation of amines.

PubMed

Deng, Weiping; Chen, Jiashu; Kang, Jincan; Zhang, Qinghong; Wang, Ye

2016-05-21

Functionalised carbon nanotube (CNT)-supported Au-Pd alloy nanoparticles were highly efficient catalysts for the aerobic oxidation of amines. We achieved the highest turnover frequencies (>1000 h(-1)) for the oxidative homocoupling of benzylamine and the oxidative dehydrogenation of dibenzylamine. We discovered a cooperative effect between Au-Pd nanoparticles and ketone/quinone groups on CNTs.

The Management of Affirmative Action Programs: A Follow-up Report.

ERIC Educational Resources Information Center

Kronovet, Esther

After initiating a survey in 1973 to study the "manager" of affirmative action programs, a followup was conducted among the same 58 public institutions throughout New York State to determine (1) whether there has been any change in the perception of the role of affirmative action officer, (2) the turnover rate among those assigned affirmative…

Losing New Graduate Bedside Nurses: A Practice Improvement Initiative

ERIC Educational Resources Information Center

Miller, Beverly

2017-01-01

New graduate nurses (NGNs) at bedside are faced with numerous challenges, which prompt them to leave jobs in their first year. The transition from being a student to competent nurse requires a NGN to have the necessary skills and experience. Subsequently, hospitals continue to face shortages of staff because of high turnover and low retention…

How Tax Relief for Training Can Make a Real Difference

ERIC Educational Resources Information Center

Wilson, Tom

2011-01-01

Companies received more than 5 billion British Pounds last year from the Exchequer in tax relief for work-related training. That is equivalent to the turnover of more than 250 further education colleges. And it vastly overshadows the 50 million British Pounds Growth and Innovation Fund set up to support employers' initiatives to improve skills and…

A Holistic Approach to Supporting the Learning of Young Indigenous Students: One Case Study

ERIC Educational Resources Information Center

Warren, Elizabeth; Quine, Janine

2013-01-01

Due to the high turnover of teaching staff in remote schools, the long-term sustainability of educational initiatives that enhance Indigenous student's learning is a major concern. This article presents a study of a remote Indigenous school (Ischool) situated in Queensland. Ischool has changed its approach to leadership, particularly the…

Identification of the sex-determining locus in grass puffer (Takifugu niphobles) provides evidence for sex-chromosome turnover in a subset of Takifugu species

PubMed Central

Atsumi, Kazufumi; Kamiya, Takashi; Nozawa, Aoi; Aoki, Yuma; Tasumi, Satoshi; Koyama, Takashi; Nakamura, Osamu; Suzuki, Yuzuru

2018-01-01

There is increasing evidence for frequent turnover in sex chromosomes in vertebrates. Yet experimental systems suitable for tracing the detailed process of turnover are rare. In theory, homologous turnover is possible if the new sex-determining locus is established on the existing sex-chromosome. However, there is no empirical evidence for such an event. The genus Takifugu includes fugu (Takifugu rubripes) and its two closely-related species whose sex is most likely determined by a SNP at the Amhr2 locus. In these species, males are heterozygous, with G and C alleles at the SNP site, while females are homozygous for the C allele. To determine if a shift in the sex-determining locus occurred in another member of this genus, we used genetic mapping to characterize the sex-chromosome systems of Takifugu niphobles. We found that the G allele of Amhr2 is absent in T. niphobles. Nevertheless, our initial mapping suggests a linkage between the phenotypic sex and the chromosome 19, which harbors the Amhr2 locus. Subsequent high-resolution analysis using a sex-reversed fish demonstrated that the sex-determining locus maps to the proximal end of chromosome 19, far from the Amhr2 locus. Thus, it is likely that homologous turnover involving these species has occurred. The data also showed that there is a male-specific reduction of recombination around the sex-determining locus. Nevertheless, no evidence for sex-chromosome differentiation was detected: the reduced recombination depended on phenotypic sex rather than genotypic sex; no X- or Y-specific maker was obtained; the YY individual was viable. Furthermore, fine-scale mapping narrowed down the new sex-determining locus to the interval corresponding to approximately 300-kb of sequence in the fugu genome. Thus, T. niphobles is determined to have a young and small sex-determining region that is suitable for studying an early phase of sex-chromosome evolution and the mechanisms underlying turnover of sex chromosome. PMID:29293639

Microaneurysm turnover in diabetic retinopathy assessed by automated RetmarkerDR image analysis--potential role as biomarker of response to ranibizumab treatment.

PubMed

Leicht, Simon F; Kernt, Marcus; Neubauer, Aljoscha; Wolf, Armin; Oliveira, Carlos Manta; Ulbig, Michael; Haritoglou, Christos

2014-01-01

To evaluate the influence of a ranibizumab treatment on microaneurysm (MA) turnover in diabetic retinopathy. Sixty-nine eyes were included in this retrospective study. We compared a group of 33 eyes with ranibizumab treatment for diabetic macular edema to 36 eyes with nonproliferative diabetic retinopathy only. Nonmydriatic ultra-widefield scanning laser ophthalmoscopy (Optomap) images were obtained at a mean 4.76 ± 1.69 days prior to the first ranibizumab injection (baseline) and again 35.94 ± 2.44 days after the third consecutive injection in a 4-week interval. In untreated controls, images were obtained at baseline and 97.81 ± 3.16 days thereafter. Images were analyzed using the RetmarkerDR software (Critical Health SA, Coimbra, Portugal), and the turnover of MAs was documented and analyzed. Thereafter, MA turnover was correlated with central retinal thickness (CRT) as assessed by OCT. At baseline, patients in the treatment group had 5.64 ± 0.75 MAs. One month after 3 ranibizumab injections, measured MAs decreased to 4.03 ± 0.66. In the untreated control group, the initial number of 3.36 ± 0.6 MAs remained almost unchanged over 3-4 months (2.89 ± 0.57 MAs). Dynamic analysis showed that after ranibizumab treatment 3.06 ± 0.5 new MAs appeared, while 5.09 ± 0.79 disappeared. In the control group, 2.11 ± 0.4 new MAs appeared and 2.61 ± 0.48 disappeared. MA turnover was significantly higher with ranibizumab compared to the control group (8.15 ± 1.14 vs. 4.72 ± 0.81, p < 0.001). Consistently, CRT decreased from 444 to 330 µm in the ranibizumab group, while there was no change in the control group (291 vs. 288 µm). The treatment of macular edema using ranibizumab does not only reduce macular thickness, but also has an impact on the turnover of MAs in diabetic retinopathy. RetmarkerDR analysis showed that more pre-existent MAs disappeared than new MAs developed, and the absolute number of MAs also decreased. © 2014 S. Karger AG, Basel.

Exploring correlates of turnover among nursing assistants in the National Nursing Home Survey.

PubMed

Temple, April; Dobbs, Debra; Andel, Ross

2011-01-01

High turnover of nursing assistants (NAs) has implications for the quality of nursing home care. Greater understanding of correlates of NA turnover is needed to provide insight into possible retention strategies. This study examined nursing home organizational characteristics and specific job characteristics of staff in relation to turnover of NAs. Cross-sectional data on 944 nationally representative nursing homes were derived from the 2004 National Nursing Home Survey. Using a 3-month turnover rate, 25% of the facilities with the lowest turnover rates were classified as low turnover, 25% of the facilities with the highest turnover were classified as high turnover, and the remaining 50% of the facilities were classified as moderate turnover. Multinomial logistic regression was used to examine organizational and job characteristics associated with low and high turnover compared with moderate turnover. One organizational characteristic, staffing levels at or greater than 4.0 hours per patient day, was associated with greater odds of low NA turnover and reduced odds of high NA turnover. Job characteristics including higher wages and union membership were associated with greater odds of low NA turnover, whereas wages, fully paid health insurance, employee assistance benefits, and involvement in resident care planning were associated with reduced odds of high NA turnover. The results of this study suggest that job characteristics of NA staff may be particularly important for turnover. Specifically, the provision of competitive wages and benefits (particularly health insurance) and involvement of NAs in resident care planning could potentially reduce NA turnover, as could maintaining high levels of nurse staffing.

Exploring correlates of turnover among nursing assistants in the National Nursing Home Survey.

PubMed

Temple, April; Dobbs, Debra; Andel, Ross

2009-01-01

High turnover of nursing assistants (NAs) has implications for the quality of nursing home care. Greater understanding of correlates of NA turnover is needed to provide insight into possible retention strategies. This study examined nursing home organizational characteristics and specific job characteristics of staff in relation to turnover of NAs. Cross-sectional data on 944 nationally representative nursing homes were derived from the 2004 National Nursing Home Survey. Using a 3-month turnover rate, 25% of the facilities with the lowest turnover rates were classified as low turnover, 25% of the facilities with the highest turnover were classified as high turnover, and the remaining 50% of the facilities were classified as moderate turnover. Multinomial logistic regression was used to examine organizational and job characteristics associated with low and high turnover compared with moderate turnover. One organizational characteristic, staffing levels at or greater than 4.0 hours per patient day, was associated with greater odds of low NA turnover and reduced odds of high NA turnover. Job characteristics including higher wages and union membership were associated with greater odds of low NA turnover, whereas wages, fully paid health insurance, employee assistance benefits, and involvement in resident care planning were associated with reduced odds of high NA turnover. The results of this study suggest that job characteristics of NA staff may be particularly important for turnover. Specifically, the provision of competitive wages and benefits (particularly health insurance) and involvement of NAs in resident care planning could potentially reduce NA turnover, as could maintaining high levels of nurse staffing.

Generalization of Turbulent Pair Dispersion to Large Initial Separations

NASA Astrophysics Data System (ADS)

Shnapp, Ron; Liberzon, Alex; International Collaboration for Turbulence Research

2018-06-01

We present a generalization of turbulent pair dispersion to large initial separations (η

Constitutive turnover of histone H2A.Z at yeast promoters requires the preinitiation complex

PubMed Central

Tramantano, Michael; Sun, Lu; Au, Christy; Labuz, Daniel; Liu, Zhimin; Chou, Mindy; Shen, Chen; Luk, Ed

2016-01-01

The assembly of the preinitiation complex (PIC) occurs upstream of the +1 nucleosome which, in yeast, obstructs the transcription start site and is frequently assembled with the histone variant H2A.Z. To understand the contribution of the transcription machinery in the disassembly of the +1 H2A.Z nucleosome, conditional mutants were used to block PIC assembly. A quantitative ChIP-seq approach, which allows detection of global occupancy change, was employed to measure H2A.Z occupancy. Blocking PIC assembly resulted in promoter-specific H2A.Z accumulation, indicating that the PIC is required to evict H2A.Z. By contrast, H2A.Z eviction was unaffected upon depletion of INO80, a remodeler previously reported to displace nucleosomal H2A.Z. Robust PIC-dependent H2A.Z eviction was observed at active and infrequently transcribed genes, indicating that constitutive H2A.Z turnover is a general phenomenon. Finally, sites with strong H2A.Z turnover precisely mark transcript starts, providing a new metric for identifying cryptic and alternative sites of initiation. DOI: http://dx.doi.org/10.7554/eLife.14243.001 PMID:27438412

Hydrocortisone Stimulation of RNA Synthesis in Induction of Hepatic Enzymes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenney, Francis T.; Wicks, Wesley D.; Greenman, David L.

Increased synthesis of hepatic enzymes due to hydrocortisone is preceded by an increase in the rate of synthesis of nuclear RNA. Pulse-labeled RNA from liver nuclei was fractionated by a differential thermal phenol procedures, and the labeled RNA of each fraction was characterized by sucrose gradient centrifugation and base composition analysis. Hormone treatment increases the rate of synthesis of three types of RNA: (1) the nuclear precursor to ribosomal RNA, (2) a rapid turnover component with base composition similar to the tissue DNA, and (3) transfer RNA. Much of the total isotope incorporation into transfer RNA can be traced tomore » turnover of the terminal adenylate residue, but this type of labeling is insensitive to the hormone. The steroid also stimulates isotope incorporation into tissue precursor pools. The effect is abolished by actinomycin and thus is secondary to the hormonal stimulation of RNA synthesis. Growth hormone stimulates RNA synthesis in both intact and adrenalectomized rats, but induces the rapid turnover enzymes (tyrosine transaminase and tryptophan pyrrolase) only in the presence of functional adrenals. It therefore seems that glucocorticoids initiate both a generalized increase in synthesis of RNA and a selective induction of specific enzymes.« less

Regulation of expression of the ligand for CD40 on T helper lymphocytes.

PubMed

Castle, B E; Kishimoto, K; Stearns, C; Brown, M L; Kehry, M R

1993-08-15

Activated Th cells deliver contact-dependent signals to resting B lymphocytes that initiate and drive B cell proliferation. Recently, a ligand for the B lymphocyte membrane protein, CD40, has been identified that delivers contact-dependent Th cell signals to B cells. A dimeric soluble form of CD40 was produced and used to further characterize the regulation of expression of the CD40 ligand. Expression of the CD40 ligand was rapidly induced after Th lymphocyte activation, and its stability depended upon whether Th cells were activated with soluble or plastic-bound stimuli. Th cells activated with soluble stimuli rapidly turned over cell-surface CD40 ligand whereas Th cells activated with plastic-bound stimuli exhibited more stable CD40 ligand expression for up to 48 h. Removal of activated Th cells from the plastic-bound stimulus resulted in a rapid turnover of CD40 ligand, suggesting that continuous stimulation could maintain CD40 ligand expression. Ligation by soluble CD40 could also stabilize expression of CD40 ligand on the Th cell surface. Both CD40 ligand and IL-2 were transiently synthesized from 1 to 12 h after Th cell activation and had similar kinetics of synthesis. In Con A-activated Th cells newly synthesized CD40 ligand exhibited an initial high turnover (1.5 h t1/2) and after 5 h of Th cell activation became more stable (10-h t1/2). In Th cells activated with plastic-bound anti-CD3, CD40 ligand exhibited a similar biphasic turnover except that the rapid turnover phase began significantly later. This delay could allow more time for newly synthesized CD40 ligand to assemble or associate with other molecules and thus become stabilized on the cell surface. Newly synthesized CD40 ligand in Con A-activated Th cells appeared to not be efficient in delivering Th cell-dependent contact signals to resting B cells, implying the need for assembly or accessory proteins. Regulation of CD40 ligand expression was consistent with all the characteristics of Th cell-delivered contact signals to B cells and may contribute to the high degree of specificity in B cell responses.

Turnover among healthcare professionals.

PubMed

Wood, Ben D

2009-01-01

Turnover among healthcare professionals is a costly consequence. The existing body of knowledge on healthcare professional turnover is correlated with job satisfaction levels. A landmark study differentiated 2 areas of job satisfaction categories: satisfiers and dissatisfiers (intrinsic and extrinsic motivators). The aim of this article is to examine existing research on precursors of turnover, such as burnout behaviors experienced by healthcare professionals, job satisfaction levels, employee organizational commitment, health complications which precede turnover, some current strategies to reduce turnover, and some effects CEO turnover has on employee turnover intentions.

SELF-TRAPPING OF DISKOSEISMIC CORRUGATION MODES IN NEUTRON STAR SPACETIMES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsang, David; Pappas, George

2016-02-10

We examine the effects of higher-order multipole contributions of rotating neutron star (NS) spacetimes on the propagation of corrugation (c-)modes within a thin accretion disk. We find that the Lense–Thirring precession frequency, which determines the propagation region of the low-frequency fundamental corrugation modes, can experience a turnover allowing for c-modes to become self-trapped for sufficiently high dimensionless spin j and quadrupole rotational deformability α. If such self-trapping c-modes can be detected, e.g., through phase-resolved spectroscopy of the iron line for a high-spin low-mass accreting neutron star, this could potentially constrain the spin-induced NS quadrupole and the NS equation of state.

Self-Trapping of Diskoseismic Corrugation Modes in Neutron Star Spacetimes

NASA Astrophysics Data System (ADS)

Tsang, David; Pappas, George

2016-02-01

We examine the effects of higher-order multipole contributions of rotating neutron star (NS) spacetimes on the propagation of corrugation (c-)modes within a thin accretion disk. We find that the Lense-Thirring precession frequency, which determines the propagation region of the low-frequency fundamental corrugation modes, can experience a turnover allowing for c-modes to become self-trapped for sufficiently high dimensionless spin j and quadrupole rotational deformability α. If such self-trapping c-modes can be detected, e.g., through phase-resolved spectroscopy of the iron line for a high-spin low-mass accreting neutron star, this could potentially constrain the spin-induced NS quadrupole and the NS equation of state.

Addressing employee turnover and retention: keeping your valued performers.

PubMed

McConnell, Charles R

2011-01-01

Employee turnover and employee retention are inextricably linked; to control turnover is to enhance retention. Turnover is a relatively simple concept; however, considerable confusion often results when addressing turnover because of differences in how it is defined; that is, what is counted, how it is counted, and how the turnover rates are expressed. Turnover is also costly, although not enough attention is paid to its cost because so much of it is indirect and thus not readily visible. There are a variety of causes of turnover, some that can be corrected and some that cannot be avoided. Reducing or otherwise controlling turnover requires continuing management attention to its causes and constant recognition of what can and should be controlled and what cannot be controlled. Ongoing attention to turnover is an essential part of the department manager's role; every improvement in turnover is a direct improvement in retention, with eventual positive effects on the bottom line.

Employee Turnover among Full-time Public Librarians.

ERIC Educational Resources Information Center

Rubin, Richard

1989-01-01

A study of employee turnover in 31 public libraries in the American Midwest established baseline turnover rates and examined the relationship of gender to turnover behavior. Findings showed that: turnover rates are low compared to other occupations; and turnover rates of males and females are similar. (28 references) (Author/MES)

Further studies of particle acceleration in cassiopeia A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chevalier, R.A.; Oegerle, W.R.; Scott, J.S.

We have further investigated models for statistical particle acceleration in the supernova remnant Cas A. Simple (three-parameter) models involving continuous second order Fermi acceleration and variable relativistic particle injection can reproduce the observed radio properties of Cas A, including the low-frequency flux anomaly first noted by Erickson and Perley. Models dominated by adiabatic expansion losses are preferable to those dominated by particle escape. The gain time determined from these models agrees well with that predicted from the hydrodynamic situation in Cas A. A model predicting the high-frequency nonthermal spectrum of Cas A indicates that the spectrum turns down in themore » optical regime due to synchrotron losses. The maximum relativistic particle energy content of Cas A was probably about several times 10/sup 49/-10/sup 50/ ergs, which can be compared with an estimated initial kinetic energy in the range 0.24 to 1.0 x 10/sup 52/ ergs. If relativistic particles can escape from Cas A, their spectra will have certain characteristics: the electron spectrum will have a turnover due to synchrotron losses and the proton spectrum will have a cutoff due to the particle gyroradii becoming larger than the sizes of the magnetic scattering centers. The observed bend in the galactic cosmic ray spectrum could be due to energy losses within the source remnant itself instead of losses incurred during propagation through the Galaxy. We also comment on other models for the relativistic electron content of Cas A.« less

Restoration of parathyroid function after change of phosphate binder from calcium carbonate to lanthanum carbonate in hemodialysis patients with suppressed serum parathyroid hormone.

PubMed

Inaba, Masaaki; Okuno, Senji; Nagayama, Harumi; Yamada, Shinsuke; Ishimura, Eiji; Imanishi, Yasuo; Shoji, Shigeichi

2015-03-01

Control of phosphate is the most critical in the treatment of chronic kidney disease with mineral and bone disorder (CKD-MBD). Because calcium-containing phosphate binder to CKD patients is known to induce adynamic bone disease with ectopic calcification by increasing calcium load, we examined the effect of lanthanum carbonate (LaC), a non-calcium containing phosphate binder, to restore bone turnover in 27 hemodialysis patients with suppressed parathyroid function (serum intact parathyroid hormone [iPTH] ≦ 150 pg/mL). At the initiation of LaC administration, the dose of calcium-containing phosphate binder calcium carbonate (CaC) was withdrawn or reduced based on serum phosphate. After initiation of LaC administration, serum calcium and phosphate decreased significantly by 4 weeks, whereas whole PTH and iPTH increased. A significant and positive correlation between decreases of serum calcium, but not phosphate, with increases of whole PTH and iPTH, suggested that the decline in serum calcium with reduction of calcium load by LaC might increase parathyroid function. Serum bone resorption markers, such as serum tartrate-resistant acid phosphatase 5b, and N-telopeptide of type I collagen increased significantly by 4 weeks after LaC administration, which was followed by increases of serum bone formation markers including serum bone alkaline phosphatase, intact procollagen N-propeptide, and osteocalcin. Therefore, it was suggested that LaC attenuated CaC-induced suppression of parathyroid function and bone turnover by decreasing calcium load. In conclusion, replacement of CaC with LaC, either partially or totally, could increase parathyroid function and resultant bone turnover in hemodialysis patients with serum iPTH ≦ 150 pg/mL. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Effects of Teriparatide Retreatment in Osteoporotic Men and Women

PubMed Central

Finkelstein, Joel S.; Wyland, Jason J.; Leder, Benjamin Z.; Burnett-Bowie, Sherri-Ann M.; Lee, Hang; Jüppner, Harald; Neer, Robert M.

2009-01-01

Context: The stimulatory effect of teriparatide on bone mineral density (BMD) and bone turnover is initially exuberant, but then diminishes. Objective: Our objective was to determine whether retreating with teriparatide after a drug-free period can restore the initial exuberant response to teriparatide. Design and Setting: This was a planned extension of a randomized controlled trial conducted in a single university hospital. Patients and Intervention: Subjects previously participated in a 30-month randomized trial comparing the effects of alendronate (group 1), teriparatide (group 2), or both (group 3) on BMD and bone turnover in men and women with low BMD (phase 1). Subjects who completed phase 1 on their assigned therapy entered phase 2 (months 30–42), during which teriparatide was stopped in groups 2 and 3. Teriparatide was administered to all subjects during months 42 to 54 (phase 3). Main Outcome Measures: We compared changes in BMD and markers of bone turnover (serum osteocalcin, N-terminal propeptide of type 1 collagen, and N-telopeptide) between phase 1 and 3 in subjects receiving teriparatide alone. Results: Posterior-anterior and lateral spine BMD increased 12.5 ± 1.5 and 16.9 ± 1.7%, respectively, during the first 12 months of teriparatide administration and 5.2 ± 0.8 and 6.2 ± 1.8%, respectively, during teriparatide retreatment (P < 0.001 and P = 0.001). Increases in osteocalcin (P < 0.001), N-terminal propeptide of type 1 collagen (P < 0.001), and N-telopeptide (P < 0.001) were greater during the first period of teriparatide administration. Conclusion: The response to teriparatide is attenuated when readministered after a 12-month hiatus. PMID:19401368

Distinctive Photosystem II Photoinactivation and Protein Dynamics in Marine Diatoms1[W

PubMed Central

Wu, Hongyan; Cockshutt, Amanda M.; McCarthy, Avery; Campbell, Douglas A.

2011-01-01

Diatoms host chlorophyll a/c chloroplasts distinct from green chloroplasts. Diatoms now dominate the eukaryotic oceanic phytoplankton, in part through their exploitation of environments with variable light. We grew marine diatoms across a range of temperatures and then analyzed their PSII function and subunit turnover during an increase in light to mimic an upward mixing event. The small diatom Thalassiosira pseudonana initially responds to increased photoinactivation under blue or white light with rapid acceleration of the photosystem II (PSII) repair cycle. Increased red light provoked only modest PSII photoinactivation but triggered a rapid clearance of a subpool of PsbA. Furthermore, PsbD and PsbB content was greater than PsbA content, indicating a large pool of partly assembled PSII repair cycle intermediates lacking PsbA. The initial replacement rates for PsbD (D2) were, surprisingly, comparable to or higher than those for PsbA (D1), and even the supposedly stable PsbB (CP47) dropped rapidly upon the light shift, showing a novel aspect of rapid protein subunit turnover in the PSII repair cycle in small diatoms. Under sustained high light, T. pseudonana induces sustained nonphotochemical quenching, which correlates with stabilization of PSII function and the PsbA pool. The larger diatom Coscinodiscus radiatus showed generally similar responses but had a smaller allocation of PSII complexes relative to total protein content, with nearly equal stiochiometries of PsbA and PsbD subunits. Fast turnover of multiple PSII subunits, pools of PSII repair cycle intermediates, and photoprotective induction of nonphotochemical quenching are important interacting factors, particularly for small diatoms, to withstand and exploit high, fluctuating light. PMID:21617029

The economic cost of using restraint and the value added by restraint reduction or elimination.

PubMed

Lebel, Janice; Goldstein, Robert

2005-09-01

The purpose of this study was to calculate the economic cost of using restraint on one adolescent inpatient service and to examine the effect of an initiative to reduce or eliminate the use of restraint after it was implemented. A detailed process-task analysis of mechanical, physical, and medication-based restraint was conducted in accordance with state and federal restraint requirements. Facility restraint data were collected, verified, and analyzed. A model was developed to determine the cost and duration of an average episode for each type of restraint. Staff time allocated to restraint activities and medication costs were computed. Calculation of the cost of restraint was restricted to staff and medication costs. Aggregate costs of restraint use and staff-related costs for one full year before the restraint reduction initiative (FY 2000) and one full year after the initiative (FY 2003) were calculated. Outcome, discharge, and recidivism data were analyzed. A comparison of the FY 2000 data with the FY 2003 data showed that the adolescent inpatient service's aggregate use of restraint decreased from 3,991 episodes to 373 episodes (91 percent), which was associated with a reduction in the cost of restraint from $1,446,740 to $117,036 (a 92 percent reduction). In addition, sick time, staff turnover and replacement costs, workers' compensation, injuries to adolescents and staff, and recidivism decreased. Adolescent Global Assessment of Functioning scores at discharge significantly improved. Implementation of a restraint reduction initiative was associated with a reduction in the use of restraint, staff time devoted to restraint, and staff-related costs. This shift appears to have contributed to better outcomes for adolescents, fewer injuries to adolescents and staff, and lower staff turnover. The initiative may have enhanced adolescent treatment and work conditions for staff.

Physical space and long-tail markets

NASA Astrophysics Data System (ADS)

Bentley, R. Alexander; Madsen, Mark E.; Ormerod, Paul

2009-03-01

The Internet is known to have had a powerful impact on on-line retailer strategies in markets characterised by long-tail distribution of sales [C. Anderson, Long Tail: Why the Future of Business is Selling Less of More, Hyperion, New York, 2006]. Such retailers can exploit the long tail of the market, since they are effectively without physical limit on the number of choices on offer. Here we examine two extensions of this phenomenon. First, we introduce turnover into the long-tail distribution of sales. Although over any given period such as a week or a month, the distribution is right-skewed and often power law distributed, over time there is considerable turnover in the rankings of sales of individual products. Second, we establish some initial results on the implications for shelf-space and physical retailers in such markets.

Staff turnover in statewide implementation of ACT: relationship with ACT fidelity and other team characteristics

PubMed Central

Rollins, Angela L.; Salyers, Michelle P.; Tsai, Jack; Lydick, Jennifer M.

2010-01-01

Staff turnover on assertive community treatment (ACT) teams is a poorly understood phenomenon. This study examined annual turnover and fidelity data collected in a statewide implementation of ACT over a 5-year period. Mean annual staff turnover across all observations was 30.0%. Turnover was negatively correlated with overall fidelity at Year 1 and 3. The team approach fidelity item was negatively correlated with staff turnover at Year 3. For 13 teams with 3 years of follow-up data, turnover rates did not change over time. Most ACT staff turnover rates were comparable or better than other turnover rates reported in the mental health and substance abuse literature. PMID:20012481

Staff turnover in statewide implementation of ACT: relationship with ACT fidelity and other team characteristics.

PubMed

Rollins, Angela L; Salyers, Michelle P; Tsai, Jack; Lydick, Jennifer M

2010-09-01

Staff turnover on assertive community treatment (ACT) teams is a poorly understood phenomenon. This study examined annual turnover and fidelity data collected in a statewide implementation of ACT over a 5-year period. Mean annual staff turnover across all observations was 30.0%. Turnover was negatively correlated with overall fidelity at Year 1 and 3. The team approach fidelity item was negatively correlated with staff turnover at Year 3. For 13 teams with 3 years of follow-up data, turnover rates did not change over time. Most ACT staff turnover rates were comparable or better than other turnover rates reported in the mental health and substance abuse literature.

The use of ene adducts to study and engineer enoyl-thioester reductases.

PubMed

Rosenthal, Raoul G; Vögeli, Bastian; Quade, Nick; Capitani, Guido; Kiefer, Patrick; Vorholt, Julia A; Ebert, Marc-Olivier; Erb, Tobias J

2015-06-01

An improved understanding of enzymes' catalytic proficiency and stereoselectivity would further enable applications in chemistry, biocatalysis and industrial biotechnology. We use a chemical probe to dissect individual catalytic steps of enoyl-thioester reductases (Etrs), validating an active site tyrosine as the cryptic proton donor and explaining how it had eluded definitive identification. This information enabled the rational redesign of Etr, yielding mutants that create products with inverted stereochemistry at wild type-like turnover frequency.

Enhanced activity of gold-supported cobalt oxide for the electrochemical evolution of oxygen.

PubMed

Yeo, Boon Siang; Bell, Alexis T

2011-04-13

Scanning electron microscopy, linear sweep voltammetry, chronoamperometry, and in situ surface-enhanced Raman spectroscopy were used to investigate the electrochemical oxygen evolution reaction (OER) occurring on cobalt oxide films deposited on Au and other metal substrates. All experiments were carried out in 0.1 M KOH. A remarkable finding is that the turnover frequency for the OER exhibited by ∼0.4 ML of cobalt oxide deposited on Au is 40 times higher than that of bulk cobalt oxide. The activity of small amounts of cobalt oxide deposited on Pt, Pd, Cu, and Co decreased monotonically in the order Au > Pt > Pd > Cu > Co, paralleling the decreasing electronegativity of the substrate metal. Another notable finding is that the OER turnover frequency for ∼0.4 ML of cobalt oxide deposited on Au is nearly three times higher than that for bulk Ir. Raman spectroscopy revealed that the as-deposited cobalt oxide is present as Co(3)O(4) but undergoes progressive oxidation to CoO(OH) with increasing anodic potential. The higher OER activity of cobalt oxide deposited on Au is attributed to an increase in fraction of the Co sites present as Co(IV) cations, a state of cobalt believed to be essential for OER to occur. A hypothesis for how Co(IV) cations contribute to OER is proposed and discussed. © 2011 American Chemical Society

Importance of trivalency and the e(g)(1) configuration in the photocatalytic oxidation of water by Mn and Co oxides.

PubMed

Maitra, Urmimala; Naidu, B S; Govindaraj, A; Rao, C N R

2013-07-16

Prompted by the early results on the catalytic activity of LiMn2O4 and related oxides in the photochemical oxidation of water, our detailed study of several manganese oxides has shown that trivalency of Mn is an important factor in determining the catalytic activity. Thus, Mn2O3, LaMnO3, and MgMn2O4 are found to be very good catalysts with turnover frequencies of 5 × 10(-4) s(-1), 4.8 × 10(-4) s(-1), and 0.8 × 10(-4) s(-1), respectively. Among the cobalt oxides, Li2Co2O4 and LaCoO3--especially the latter--exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10(-4) s(-1) and 1.4 × 10(-3) s(-1), respectively. The common feature among the catalytic Mn and Co oxides is not only that Mn and Co are in the trivalent state, but Co(3+) in the Co oxides is in the intermediate t2g(5)e(g)(1) state whereas Mn(3+) is in the t2g(3e(g)(1) state. The presence of the e(g)(1) electron in these Mn and Co oxides is considered to play a crucial role in the photocatalytic properties of the oxides.

Importance of trivalency and the eg1 configuration in the photocatalytic oxidation of water by Mn and Co oxides

PubMed Central

Maitra, Urmimala; Naidu, B. S.; Govindaraj, A.; Rao, C. N. R.

2013-01-01

Prompted by the early results on the catalytic activity of LiMn2O4 and related oxides in the photochemical oxidation of water, our detailed study of several manganese oxides has shown that trivalency of Mn is an important factor in determining the catalytic activity. Thus, Mn2O3, LaMnO3, and MgMn2O4 are found to be very good catalysts with turnover frequencies of 5 × 10−4 s−1, 4.8 × 10−4 s−1, and 0.8 ×10−4 s−1, respectively. Among the cobalt oxides, Li2Co2O4 and LaCoO3—especially the latter—exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10−4 s−1 and 1.4 × 10−3 s−1, respectively. The common feature among the catalytic Mn and Co oxides is not only that Mn and Co are in the trivalent state, but Co3+ in the Co oxides is in the intermediate t2g5eg1 state whereas Mn3+ is in the t2g3eg1 state. The presence of the eg1 electron in these Mn and Co oxides is considered to play a crucial role in the photocatalytic properties of the oxides. PMID:23818589

When Teachers Give Up: Teacher Burnout, Teacher Turnover and Their Impact on Children.

ERIC Educational Resources Information Center

Dworkin, Anthony Gary

A large-scale sociological study of teacher burnout in the public schools is summarized. Data presented in the study consist of: a sample of 3,500 teachers in Houston, whose attitudes were monitored in 1977; exit interviews of every teacher in the initial sample who subsequently quit teaching over a 5-year period; achievement and attendance…

Assessing the Relationship of Teacher Self-Efficacy, Job Satisfaction, and Perception of Work-Life Balance of Louisiana Agriculture Teachers

ERIC Educational Resources Information Center

Blackburn, J. Joey; Bunchm, J. C.; Haynes, J. Chris

2017-01-01

Agricultural education has faced a national shortage of qualified teachers since 1965. Initiatives, such as NAAE's TeachAg Campaign, seek to alleviate this shortage through recruitment of new agriculture teachers. However, turnover in the teaching profession remains a problem, with attrition rates approaching 60% reported in some research studies.…

Second Line of Defense, Megaports Initiative, Operational Testing and Evaluation Plan, Port of Lazaro Cardenas, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, Jamie D.

2012-05-30

The purpose of the Operational Testing and Evaluation (OT&E) phases of the project is to prepare for turnover of the Megaports System supplied by U.S. Department of Energy/National Nuclear Security Administration (DOE/NNSA)—located at the Export Lanes of the Port of Lazaro Cardenas, Mexico—to the Government of Mexico (GOM).

The Regulation of Skeletal Muscle Protein Turnover during the Progression of Cancer Cachexia in the ApcMin/+ Mouse

PubMed Central

White, James P.; Baynes, John W.; Welle, Stephen L.; Kostek, Matthew C.; Matesic, Lydia E.; Sato, Shuichi; Carson, James A.

2011-01-01

Muscle wasting that occurs with cancer cachexia is caused by an imbalance in the rates of muscle protein synthesis and degradation. The ApcMin/+ mouse is a model of colorectal cancer that develops cachexia that is dependent on circulating IL-6. However, the IL-6 regulation of muscle protein turnover during the initiation and progression of cachexia in the ApcMin/+ mouse is not known. Cachexia progression was studied in ApcMin/+ mice that were either weight stable (WS) or had initial (≤5%), intermediate (6–19%), or extreme (≥20%) body weight loss. The initiation of cachexia reduced %MPS 19% and a further ∼50% with additional weight loss. Muscle IGF-1 mRNA expression and mTOR targets were suppressed with the progression of body weight loss, while muscle AMPK phosphorylation (Thr 172), AMPK activity, and raptor phosphorylation (Ser 792) were not increased with the initiation of weight loss, but were induced as cachexia progressed. ATP dependent protein degradation increased during the initiation and progression of cachexia. However, ATP independent protein degradation was not increased until cachexia had progressed beyond the initial phase. IL-6 receptor antibody administration prevented body weight loss and suppressed muscle protein degradation, without any effect on muscle %MPS or IGF-1 associated signaling. In summary, the %MPS reduction during the initiation of cachexia is associated with IGF-1/mTOR signaling repression, while muscle AMPK activation and activation of ATP independent protein degradation occur later in the progression of cachexia. IL-6 receptor antibody treatment blocked cachexia progression through the suppression of muscle protein degradation, while not rescuing the suppression of muscle protein synthesis. Attenuation of IL-6 signaling was effective in blocking the progression of cachexia, but not sufficient to reverse the process. PMID:21949739

Initial posting-a critical stage in the employment cycle: lessons from the experience of government doctors in Gujarat, India.

PubMed

Purohit, Bhaskar; Martineau, Tim

2016-07-11

With the critical shortage of government doctors serving in rural health centers in India, understanding the initial posting policies, processes, and practices become important from a retention point of view. The initial posting is a very critical stage of an employment cycle and could play an important role in influencing the key human resource for health outcomes such as turnover and performance. The current study aimed at exploring a rather unknown phenomenon of the initial posting-related processes, practices, and perceptions of Medical Officers working with the Public Health Department in Gujarat, India. This was an exploratory study carried out in the state of Gujarat, India, that used qualitative methods first to document the extant initial posting policy with the help of document review and five Key Informant interviews; next, 19 in-depth interviews were carried out with Medical Officers to assess implementation of policies as well as processes and systems related to the initial posting of Medical Officers. A thematic framework approach was used to analyze qualitative data using NVIVO. The results indicate that there is no formal published or written initial posting policy in the state, and in the absence of a written and formal policy, the overall posting systems were perceived to be arbitrary by the study respondents. In the absence of any policy, the state has some unwritten informal practices such as posting the Medical Officers at their native places. Although this practice reflects a concern towards the Medical Officer's needs, such practices are not consistently applied indicating some inequity and possible implications over Medical Officers' retention and motivation. Initial posting is a critical aspect of an employment cycle, and the perceptions and experiences of MOs regarding the processes and practices involved in their initial posting can be crucial in influencing their performance and turnover rates. If long-term solutions are to be sought in addressing the availability and distribution of Medical Officers in the state, then there is a need to have clearly laid down initial posting-related policies that reflect the equity and consideration towards Medical Officers in placement-related matters.

Differences in Bone Quality between High versus Low Turnover Renal Osteodystrophy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porter, Daniel S.; Pienkowski, David; Faugere, Marie-Claude

2012-01-01

Abnormal bone turnover is common in chronic kidney disease (CKD), but its effects on bone quality remain unclear. This study sought to quantify the relationship between abnormal bone turnover and bone quality. Iliac crest bone biopsies were obtained from CKD-5 patients on dialysis with low (n=18) or high (n=17) turnover, and from volunteers (n=12) with normal turnover and normal kidney function. Histomorphometric methods were used to quantify the microstructural parameters; Fourier transform infrared spectroscopy and nanoindentation were used to quantify the material and mechanical properties in bone. Reduced mineral-to-matrix ratio, mineral crystal size, stiffness and hardness were observed in bonemore » with high turnover compared to bone with normal or low turnover. Decreased cancellous bone volume and trabecular thickness were seen in bone with low turnover compared to bone with normal or high turnover. Bone quality, as defined by its microstructural, material, and mechanical properties, is related to bone turnover. These data suggest that turnover related alterations in bone quality may contribute to the known diminished mechanical competence of bone in CKD patients, albeit from different mechanisms for bone with high (material abnormality) vs. low (microstructural alteration) turnover. The present findings suggest that improved treatments for renal osteodystrophy should seek to avoid low or high bone turnover and aim for turnover rates as close to normal as possible.« less

Turnover among Community Mental Health Workers in Ohio.

PubMed

Bukach, Ashley M; Ejaz, Farida K; Dawson, Nicole; Gitter, Robert J

2017-01-01

This study examined turnover of community mental health workers in 42 randomly selected mental health agencies in Ohio. The turnover rate in 2011 was 26 %. A regression analysis indicated that agencies with lower turnover offered higher maximum pay and were smaller in size, while those offering career advancement opportunities, such as career ladder programs, had higher turnover. The findings suggest that improving wages for workers is likely to reduce turnover. It is also possible that smaller agencies have lower turnover due to stronger relationships with workers and/or more successful hiring practices. Furthermore, turnover that occurs as a result of career advancement could have positive effects and should be examined separate from other types of turnover in the future.

Efficient Hydrogen Storage and Production Using a Catalyst with an Imidazoline-Based, Proton-Responsive Ligand.

PubMed

Wang, Lin; Onishi, Naoya; Murata, Kazuhisa; Hirose, Takuji; Muckerman, James T; Fujita, Etsuko; Himeda, Yuichiro

2017-03-22

A series of new imidazoline-based iridium complexes has been developed for hydrogenation of CO 2 and dehydrogenation of formic acid. One of the proton-responsive complexes bearing two -OH groups at ortho and para positions on a coordinating pyridine ring (3 b) can catalyze efficiently the chemical fixation of CO 2 and release H 2 under mild conditions in aqueous media without using organic additives/solvents. Notably, hydrogenation of CO 2 can be efficiently carried out under CO 2 and H 2 at atmospheric pressure in basic water by 3 b, achieving a turnover frequency of 106 h -1 and a turnover number of 7280 at 25 °C, which are higher than ever reported. Moreover, highly efficient CO-free hydrogen production from formic acid in aqueous solution employing the same catalyst under mild conditions has been achieved, thus providing a promising potential H 2 -storage system in water. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sunlight-Dependent Hydrogen Production by Photosensitizer/Hydrogenase Systems.

PubMed

Adam, David; Bösche, Lisa; Castañeda-Losada, Leonardo; Winkler, Martin; Apfel, Ulf-Peter; Happe, Thomas

2017-03-09

We report a sustainable in vitro system for enzyme-based photohydrogen production. The [FeFe]-hydrogenase HydA1 from Chlamydomonas reinhardtii was tested for photohydrogen production as a proton-reducing catalyst in combination with eight different photosensitizers. Using the organic dye 5-carboxyeosin as a photosensitizer and plant-type ferredoxin PetF as an electron mediator, HydA1 achieves the highest light-driven turnover number (TON HydA1 ) yet reported for an enzyme-based in vitro system (2.9×10 6  mol(H 2 ) mol(cat) -1 ) and a maximum turnover frequency (TOF HydA1 ) of 550 mol(H 2 ) mol(HydA1) -1  s -1 . The system is fueled very effectively by ambient daylight and can be further simplified by using 5-carboxyeosin and HydA1 as a two-component photosensitizer/biocatalyst system without an additional redox mediator. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catechol Removal from Aqueous Media Using Laccase Immobilized in Different Macro- and Microreactor Systems.

PubMed

Tušek, Ana Jurinjak; Šalić, Anita; Zelić, Bruno

2017-08-01

Laccase belongs to the group of enzymes that are capable to catalyze the oxidation of phenols. Since the water is only by-product in laccase-catalyzed phenol oxidations, it is ideally "green" enzyme with many possible applications in different industrial processes. To make the oxidation process more sustainable in terms of biocatalyst consumption, immobilization of the enzyme is implemented in to the processes. Additionally, when developing a process, choice of a reactor type plays a significant role in the total outcome.In this study, the use of immobilized laccase from Trametes versicolor for biocatalytic catechol oxidation was explored. Two different methods of immobilization were performed and compared using five different reactor types. In order to compare different systems used for catechol oxidation, biocatalyst turnover number and turnover frequency were calculated. With low consumption of the enzyme and good efficiency, obtained results go in favor of microreactors with enzyme covalently immobilized on the microchannel surface.

Is the ecological belt zonation of the Swiss Alps relevant for moth diversity and turnover?

NASA Astrophysics Data System (ADS)

Beck, Jan; Rüdlinger, Cecil M.; McCain, Christy M.

2017-04-01

Mountain ecosystems are traditionally envisioned as elevational belts of homogenous vegetation, separated by intervening ecotones. Recent research has cast doubt on such predictable layering at least in animal communities. We test the link of two a priori defined ecological belt zonations to noctuid moth distributions in the Swiss Alps. Predictions, in particular, were a coincidence of proposed ecotones with increased range endpoint frequencies and with increased species turnover or species richness between equidistant elevational bands. Using >320,000 distributional records for >500 noctuid species, we found no support for these three predictions despite several contrasting analytical approaches. Concurrent with recently published vertebrate data, we conclude that simple ecological belt zonations are unrelated to the moth communities found along mountain slopes. Rather, species are distributed idiosyncratically following their specific niche requirements. Additional rigorous evidence, particularly comparing insect clades spanning a spectrum of host-plant relationships, may be required to support the relevance of the ecological belt concept in structuring mountain ecosystems beyond tree and plant communities.

Nickel centred H+ reduction catalysis in a model of [NiFe] Hydrogenase

PubMed Central

Brazzolotto, Deborah; Gennari, Marcello; Queyriaux, Nicolas; Simmons, Trevor R.; Pécaut, Jacques; Demeshko, Serhiy; Meyer, Franc; Orio, Maylis; Artero, Vincent; Duboc, Carole

2017-01-01

Hydrogen production through water splitting is one of the most promising solutions for the storage of renewable energy. [NiFe] hydrogenases are organometallic enzymes containing nickel and iron centers that catalyze hydrogen evolution with performances that rival those of platinum. These enzymes provide inspiration for the design of new molecular catalysts that do not require precious metals. However, all heterodinuclear NiFe models reported so far do not reproduce the Ni-centered reactivity found at the active site of [NiFe] hydrogenases. Here we report a structural and functional NiFe mimic that displays reactivity at the Ni site. This is shown by the detection of two catalytic intermediates that reproduce structural and electronic features of the Ni-L and Ni-R states of the enzyme during catalytic turnover. Under electrocatalytic conditions, this mimic displays high rates for H2 evolution (second order rate constant of 2.5 104 M-1s-1; turnover frequency of 225 s-1 at 10 mM H+ concentration) from mildly acidic solutions. PMID:27768098

Efficient Light-Driven Water Oxidation Catalysis by Dinuclear Ruthenium Complexes.

PubMed

Berardi, Serena; Francàs, Laia; Neudeck, Sven; Maji, Somnath; Benet-Buchholz, Jordi; Meyer, Franc; Llobet, Antoni

2015-11-01

Mastering the light-induced four-electron oxidation of water to molecular oxygen is a key step towards the achievement of overall water splitting to produce alternative solar fuels. In this work, we report two rugged molecular pyrazolate-based diruthenium complexes that efficiently catalyze visible-light-driven water oxidation. These complexes were fully characterized both in the solid state (by X-ray diffraction analysis) and in solution (spectroscopically and electrochemically). Benchmark performances for homogeneous oxygen production have been obtained for both catalysts in the presence of a photosensitizer and a sacrificial electron acceptor at pH 7, and a turnover frequency of up to 11.1 s(-1) and a turnover number of 5300 were obtained after three successive catalytic runs. Under the same experimental conditions with the same setup, the pyrazolate-based diruthenium complexes outperform other well-known water oxidation catalysts owing to both electrochemical and mechanistic aspects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-resolution single-molecule fluorescence imaging of zeolite aggregates within real-life fluid catalytic cracking particles.

PubMed

Ristanović, Zoran; Kerssens, Marleen M; Kubarev, Alexey V; Hendriks, Frank C; Dedecker, Peter; Hofkens, Johan; Roeffaers, Maarten B J; Weckhuysen, Bert M

2015-02-02

Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50-150 μm-sized FCC spheres heavily influence their catalytic performance. Single-molecule fluorescence-based imaging methods, namely nanometer accuracy by stochastic chemical reactions (NASCA) and super-resolution optical fluctuation imaging (SOFI) were used to study the catalytic activity of sub-micrometer zeolite ZSM-5 domains within real-life FCC catalyst particles. The formation of fluorescent product molecules taking place at Brønsted acid sites was monitored with single turnover sensitivity and high spatiotemporal resolution, providing detailed insight in dispersion and catalytic activity of zeolite ZSM-5 aggregates. The results point towards substantial differences in turnover frequencies between the zeolite aggregates, revealing significant intraparticle heterogeneities in Brønsted reactivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water reduction by a p-GaInP2 photoelectrode stabilized by an amorphous TiO2 coating and a molecular cobalt catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Jing; Yan, Yong; Young, James L.

2015-12-21

Producing hydrogen through solar water splitting requires the coverage of large land areas. Abundant metal-based molecular catalysts offer scalability, but only if they match noble metal activities. We report on a highly active p-GaInP2 photocathode protected through a 35-nm TiO2 layer functionalized by a cobaloxime molecular catalyst (GaInP2-TiO2-cobaloxime). This photoelectrode mediates H2 production with a current density of ~9"0mA"0cm-2 at a potential of 0"0V versus RHE under 1-sun illumination at pH"013. The calculated turnover number for the catalyst during a 20-h period is 139,000, with an average turnover frequency of 1.9"0s-1. Bare GaInP2 shows a rapid current decay, whereas themore » GaInP2-TiO2-cobaloxime electrode shows« less

Cavitand-Based Polyphenols as Highly Reactive Organocatalysts for the Coupling of Carbon Dioxide and Oxiranes.

PubMed

Martínez-Rodríguez, Luis; Otalora Garmilla, Javier; Kleij, Arjan W

2016-04-07

A variety of cavitand-based polyphenols was prepared from cheap and accessible aldehyde and resorcinol/pyrogallol reagents to give the respective resorcin[4]- or pyrogallol[4]arenes. The preorganization of the phenolic units allows intra- and intermolecular hydrogen bond (HB) networks that affect both the reactivity and stability of these HB-donor catalysts. Unexpectedly, we found that the resorcin[4]arenes show cooperative catalysis behavior compared to the parent resorcinol in the catalytic coupling of epoxides and CO2 with a significantly higher turnover. At elevated reaction temperatures, the resorcin[4]arene-based catalyst 3 d displays the best catalytic performance with very high turnover numbers and frequencies, combining increased reactivity and stability compared to pyrogallol, and an ample substrate scope. This type of polyphenol structure thus illustrates the importance of a new, highly competitive organocatalyst design to devise sustainable CO2 conversion processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The longitudinal study of turnover and the cost of turnover in emergency medical services.

PubMed

Patterson, P Daniel; Jones, Cheryl B; Hubble, Michael W; Carr, Matthew; Weaver, Matthew D; Engberg, John; Castle, Nicholas

2010-01-01

Few studies have examined employee turnover and associated costs in emergency medical services (EMS). To quantify the mean annual rate of turnover, total median cost of turnover, and median cost per termination in a diverse sample of EMS agencies. A convenience sample of 40 EMS agencies was followed over a six-month period. Internet, telephone, and on-site data-collection methods were used to document terminations, new hires, open positions, and costs associated with turnover. The cost associated with turnover was calculated based on a modified version of the Nursing Turnover Cost Calculation Methodology (NTCCM). The NTCCM identified direct and indirect costs through a series of questions that agency administrators answered monthly during the study period. A previously tested measure of turnover to calculate the mean annual rate of turnover was used. All calculations were weighted by the size of the EMS agency roster. The mean annual rate of turnover, total median cost of turnover, and median cost per termination were determined for three categories of agency staff mix: all-paid staff, mix of paid and volunteer (mixed) staff, and all-volunteer staff. The overall weighted mean annual rate of turnover was 10.7%. This rate varied slightly across agency staffing mix (all-paid = 10.2%, mixed = 12.3%, all-volunteer = 12.4%). Among agencies that experienced turnover (n = 25), the weighted median cost of turnover was $71,613.75, which varied across agency staffing mix (all-paid = $86,452.05, mixed = $9,766.65, and all-volunteer = $0). The weighted median cost per termination was $6,871.51 and varied across agency staffing mix (all-paid = $7,161.38, mixed = $1,409.64, and all-volunteer = $0). Annual rates of turnover and costs associated with turnover vary widely across types of EMS agencies. The study's mean annual rate of turnover was lower than expected based on information appearing in the news media and EMS trade magazines. Findings provide estimates of two key workforce measures--turnover rates and costs--where previously none have existed. Local EMS directors and policymakers at all levels of government may find the results and study methodology useful toward designing and evaluating programs targeting the EMS workforce.

Turnover of regulated nurses in long-term care facilities.

PubMed

Chu, Charlene H; Wodchis, Walter P; McGilton, Katherine S

2014-07-01

To describe the relationship between nursing staff turnover in long-term care (LTC) homes and organisational factors consisting of leadership practices and behaviours, supervisory support, burnout, job satisfaction and work environment satisfaction. The turnover of regulated nursing staff [Registered Nurses (RNs) and Registered Practical Nurses (RPNs)] in LTC facilities is a pervasive problem, but there is a scarcity of research examining this issue in Canada. The study was conceptualized using a Stress Process model. Distinct surveys were distributed to administrators to measure organisational factors and to regulated nurses to measure personal and job-related sources of stress and workplace support. In total, 324 surveys were used in the linear regression analysis to examine factors associated with high turnover rates. Higher leadership practice scores were associated with lower nursing turnover; a one score increase in leadership correlated with a 49% decrease in nursing turnover. A significant inverse relationship between leadership turnover and nurse turnover was found: the higher the administrator turnover the lower the nurse turnover rate. Leadership practices and administrator turnover are significant in influencing regulated nurse turnover in LTC. Long-term care facilities may want to focus on building good leadership and communication as an upstream method to minimize nurse turnover. © 2013 John Wiley & Sons Ltd.

Giant Metrewave Radio Telescope Monitoring of the Black Hole X-Ray Binary, V404 Cygni during Its 2015 June Outburst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandra, Poonam; Kanekar, Nissim

We report results from a Giant Metrewave Radio Telescope (GMRT) monitoring campaign of the black hole X-ray binary V404 Cygni during its 2015 June outburst. The GMRT observations were carried out at observing frequencies of 1280, 610, 325, and 235 MHz, and extended from June 26.89 UT (a day after the strongest radio/X-ray outburst) to July 12.93 UT. We find the low-frequency radio emission of V404 Cygni to be extremely bright and fast-decaying in the outburst phase, with an inverted spectrum below 1.5 GHz and an intermediate X-ray state. The radio emission settles to a weak, quiescent state ≈11 daysmore » after the outburst, with a flat radio spectrum and a soft X-ray state. Combining the GMRT measurements with flux density estimates from the literature, we identify a spectral turnover in the radio spectrum at ≈1.5 GHz on ≈ June 26.9 UT, indicating the presence of a synchrotron self-absorbed emitting region. We use the measured flux density at the turnover frequency with the assumption of equipartition of energy between the particles and the magnetic field to infer the jet radius (≈4.0 × 10{sup 13} cm), magnetic field (≈0.5 G), minimum total energy (≈7 × 10{sup 39} erg), and transient jet power (≈8 × 10{sup 34} erg s{sup −1}). The relatively low value of the jet power, despite V404 Cygni’s high black hole spin parameter, suggests that the radio jet power does not correlate with the spin parameter.« less

High-temperature langatate elastic constants and experimental validation up to 900 degrees C.

PubMed

Davulis, Peter M; da Cunha, Mauricio Pereira

2010-01-01

This paper reports on a set of langatate (LGT) elastic constants extracted from room temperature to 1100 degrees C using resonant ultrasound spectroscopy techniques and an accompanying assessment of these constants at high temperature. The evaluation of the constants employed SAW device measurements from room temperature to 900 degrees C along 6 different LGT wafer orientations. Langatate parallelepipeds and wafers were aligned, cut, ground, and polished, and acoustic wave devices were fabricated at the University of Maine facilities along specific orientations for elastic constant extraction and validation. SAW delay lines were fabricated on LGT wafers prepared at the University of Maine using 100-nm platinumrhodium- zirconia electrodes capable of withstanding temperatures up to 1000 degrees C. The numerical predictions based on the resonant ultrasound spectroscopy high-temperature constants were compared with SAW phase velocity, fractional frequency variation, and temperature coefficients of delay extracted from SAW delay line frequency response measurements. In particular, the difference between measured and predicted fractional frequency variation is less than 2% over the 25 degrees C to 900 degrees C temperature range and within the calculated and measured discrepancies. Multiple temperature-compensated orientations at high temperature were predicted and verified in this paper: 4 of the measured orientations had turnover temperatures (temperature coefficient of delay = 0) between 200 and 420 degrees C, and 2 had turnover temperatures below 100 degrees C. In summary, this work reports on extracted high-temperature elastic constants for LGT up to 1100 degrees C, confirmed the validity of those constants by high-temperature SAW device measurements up to 900 degrees C, and predicted and identified temperature-compensated LGT orientations at high temperature.

A LOW FREQUENCY SURVEY OF GIANT PULSES FROM THE CRAB PULSAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eftekhari, T.; Stovall, K.; Dowell, J.

2016-10-01

We present a large survey of giant pulses from the Crab Pulsar as observed with the first station of the Long Wavelength Array. Automated methods for detecting giant pulses at low frequencies where scattering becomes prevalent are also explored. More than 1400 pulses were detected across four frequency bands between 20 and 84 MHz over a seven-month period beginning in 2013, with additional followup observations in late 2014 and early 2015. A handful of these pulses were detected simultaneously across all four frequency bands. We examine pulse characteristics, including pulse broadening and power law indices for amplitude distributions. We findmore » that the flux density increases toward shorter wavelengths, consistent with a spectral turnover at 100 MHz. Our observations uniquely span multiple scattering epochs, manifesting as a notable trend in the number of detections per observation. These results are characteristic of the variable interface between the synchrotron nebula and the surrounding interstellar medium.« less

Job Demand and Job Satisfaction in Latent Groups of Turnover Intention Among Licensed Nurses in Taiwan Nursing Homes.

PubMed

Chen, I-Hui; Brown, Roger; Bowers, Barbara J; Chang, Wen-Yin

2015-10-01

Nurses' turnover intention is not dichotomous; it may reflect intent to leave the profession, intent to leave a type of facility, or intent to leave a specific workplace. In a latent class analysis (LCA) of data from 186 licensed nurses (RNs and LPNs) recruited from 25 nursing homes (NHs) in Taiwan, we classified nurses into turnover intention subgroups based on seven questionnaire items and used a multilevel contrast analysis to characterize the subgroups according to demographic and facility factors, job demand, and job satisfaction. A multilevel probit model was used to examine how job demand and job satisfaction influenced subgroup membership. Three turnover subgroups were identified: high turnover intention (12%), middle turnover intention (57%), and low turnover intention (31%). The high turnover intention subgroup comprised the youngest nurses and had the lowest percentage of registered nurses (RNs); nurses in this subgroup had worked the longest at the current NH and had the greatest likelihood of working at a for-profit facility. Nurses in the middle turnover intention subgroup had the lowest likelihood of working at a for-profit facility. Nurses in the low turnover intention subgroup were primarily RNs and had the shortest work experience in the current facility. Nurses in the high and middle turnover intention subgroups reported lower intrinsic job satisfaction than those with low turnover intention. Extrinsic job satisfaction mediated the relationship between job demand and turnover intention subgroup assignment. The results of this LCA can help target interventions to address heterogeneity of turnover intention and ultimately lessen turnover. © 2015 Wiley Periodicals, Inc.

The costs of nurse turnover: part 1: an economic perspective.

PubMed

Jones, Cheryl Bland

2004-12-01

Nurse turnover is costly for healthcare organizations. Administrators and nurse executives need a reliable estimate of nurse turnover costs and the origins of those costs if they are to develop effective measures of reducing nurse turnover and its costs. However, determining how to best capture and quantify nurse turnover costs can be challenging. Part 1 of this series conceptualizes nurse turnover via human capital theory and presents an update of a previously developed method for determining the costs of nurse turnover, the Nursing Turnover Cost Calculation Method. Part 2 (January 2005) presents a recent application of the methodology in an acute care hospital.

Effect of electric signal frequency and form on physical-chemical oxidation of organic wastes

NASA Astrophysics Data System (ADS)

Morozov, Yegor; Tikhomirov, Alexander A.; Trifonov, Sergey V.; Kudenko, D.. Yurii A.

The behavior conditions of physical-chemical reactions securing organic wastes’ oxidation in H _{2}O _{2} aqueous medium aimed at an increase of mass exchange processes in a life support system (LSS) for a space purpose have been under study. The character of dependence of organic wastes oxidation rate in H _{2}O _{2} aqueous medium, activated with alternating current of different frequency and form have been considered. Ways of those parameters optimization for the purpose to efficiently increase the physical-chemical decomposition of organic wastes in LSS have been proposed. Specifically, power consumption and reaction time of wastes mineralization have been determined to reduce more than twice. Involvement ways of mineralized organic wastes received in intrasystem mass exchange have been shown. Application feasibility of the obtained results both for space and terrestrial purpose has been discussed. Key words: life support sustem, mineralization, turnover, frequency, organic wastes

Patient Turnover: A Concept Analysis.

PubMed

VanFosson, Christopher A; Yoder, Linda H; Jones, Terry L

Patient turnover influences the quality and safety of patient care. However, variations in the conceptual underpinnings of patient turnover limit the understanding of the phenomenon. A concept analysis was completed to clarify the role of patient turnover in relation to outcomes in the acute care hospital setting. The defining attributes, antecedents, consequences, and empirical referents of patient turnover were proposed. Nursing leaders should account for patient turnover in workload and staffing calculations. Further research is needed to clarify the influence of patient turnover on the quality and safety of nursing care using a unified understanding of the phenomenon.

Evolution and Spectrum of the Radio Emission of Tycho's Supernova Remnant

NASA Astrophysics Data System (ADS)

Vinyaikin, E. N.

2018-02-01

The radio spectrum of Tycho's Supernova Remnant is constructed at frequencies 12.6-143 000 MHz for epoch 2010.3, taking into account the secular decrease in the radio flux density of the remnant at the rate d = -(0.46 ± 0.03)%/year: S_ν ^{3C10} (t = 2010.3) = (43.1 ± 1.8 Jy)(ν [GHz])^{ - (0.592 ± 0.019) + (0.041 ± 0.012)log (ν [GHz])} . The spectrum has positive curvature. The presence of a low-frequency turnover in the spectrum of the radio source 3C10 with its maximum at 7.7 MHz is predicted, due to absorption in the interstellar medium in the direction toward the source.

Directivity of the radio emission from the K1 dwarf star AB Doradus

NASA Technical Reports Server (NTRS)

Lim, Jeremy; White, Stephen M.; Nelson, Graam J.; Benz, Arnold O.

1994-01-01

We present measurements of the spectrum and polarization of the flaring radio emission from the K1 dwarf star AB Doradus, together with previously reported single frequency measurements (with no polarization information) on 3 other days. On all 4 days spanning a 6 month period, the emission was strong and, when folded with the stellar rotation period, showed similar time variations with two prominant peaks at phase 0.35 and 0.75. These peaks coincide in longitude with two large starspots identified from the stellar optical light curve and have half-powe widths as small as 0.1 rotations and no larger than 0.2 rotations. The modulated emission shows no measurable circular polarization, and its two peaks have different turnover frequencies.

The effects of sexual harassment on turnover in the military: time-dependent modeling.

PubMed

Sims, Carra S; Drasgow, Fritz; Fitzgerald, Louise F

2005-11-01

Sexual harassment has consistently negative consequences for working women, including changes in job attitudes (e.g., lower satisfaction) and behaviors (e.g., increased work withdrawal). Cross-sectional evidence suggests that harassment influences turnover intentions. However, few studies have used actual turnover; rather, they rely on proxies. With a sample of 11,521 military servicewomen with turnover data spanning approximately 4 years, the authors used the appropriate method for longitudinal turnover data--Cox's regression--to investigate the impact of harassment on actual turnover. Experiences of harassment led to increased turnover, even after controlling for job satisfaction, organizational commitment, and marital status. Among officers, harassment also affected turnover over and above rank. Given turnover's relevance to organizational bottom lines, these findings have important implications not only for individual women but also for organizations. ((c) 2005 APA, all rights reserved).

Panchromatic Sensitization Using Zn(II) Porphyrin-Based Photosensitizers for Light-Driven Hydrogen Production in Water.

PubMed

Ho, Po-Yu; Mark, Michael F; Wang, Yi; Yiu, Sze-Chun; Yu, Wai-Hong; Ho, Cheuk-Lam; McCamant, David W; Eisenberg, Richard; Huang, Shuping

2018-06-19

Three molecular photosensitizers (PSs) with carboxylic acid anchors for attachment to platinized titanium dioxide nanoparticles were studied for light-driven hydrogen production from a fully aqueous medium with ascorbic acid (AA) as the sacrificial electron donor. Two zinc(II) porphyrin (ZnP) based PSs (ZnP-dyad and YD2-o-C8) were used to examine the effect of panchromatic sensitization in promoting photocatalytic H2 generation. A dyad molecular design was used to construct the Bodipy-conjugated ZnP PS (ZnP-dyad) and another one was featured with an electron-donating diarylamino moiety (YD2-o-C8). In order to probe the good use of the ZnP scaffold in this particular energy conversion process, an organic PS without the ZnP moiety (Bodipy-dye) was also synthesized for comparison. Ultrafast transient absorption spectroscopy was adopted to map out the energy transfer processes occurring in the dyad and establish the Bodipy-based antenna effect. In particular, the systems with YD2-o-C8 and ZnP-dyad achieve a remarkable initial activity in H2 production with an initial turnover frequency (TOFi) larger than 300 h-1 under white light irradiation. In brief, the use of ZnP PSs in dye-sensitized photocatalysis for H2 evolution reaction in this study indicates the importance of panchromatic sensitization capability for the development of light absorbing PSs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The longitudinal study of turnover and the cost of turnover in EMS

PubMed Central

Patterson, P. Daniel; Jones, Cheryl B.; Hubble, Michael W.; Carr, Matthew; Weaver, Matthew D.; Engberg, John; Castle, Nicholas

2010-01-01

Purpose Few studies have examined employee turnover and associated costs in emergency medical services (EMS). The purpose of this study was to quantify the mean annual rate of turnover, total median cost of turnover, and median cost per termination in a diverse sample of EMS agencies. Methods A convenience sample of 40 EMS agencies was followed over a 6 month period. Internet, telephone, and on-site data collection methods were used to document terminations, new hires, open positions, and costs associated with turnover. The cost associated with turnover was calculated based on a modified version of the Nursing Turnover Cost Calculation Methodology (NTCCM). The NTCCM identified direct and indirect costs through a series of questions that agency administrators answered monthly during the study period. A previously tested measure of turnover to calculate the mean annual rate of turnover was used. All calculations were weighted by the size of the EMS agency roster. The mean annual rate of turnover, total median cost of turnover, and median cost per termination were determined for 3 categories of agency staff mix: all paid staff, mix of paid and volunteer (mixed), and all-volunteer. Results The overall weighted mean annual rate of turnover was 10.7%. This rate varied slightly across agency staffing mix: (all-paid=10.2%, mixed=12.3%, all-volunteer=12.4%). Among agencies that experienced turnover (n=25), the weighted median cost of turnover was $71,613.75, which varied across agency staffing mix: (all-paid=$86,452.05, mixed=$9,766.65, and all-volunteer=$0). The weighted median cost per termination was $6,871.51 and varied across agency staffing mix: (all-paid=$7,161.38, mixed=$1,409.64, and all-volunteer=$0). Conclusions Annual rates of turnover and costs associated with turnover vary widely across types of EMS agencies. The study’s mean annual rate of turnover was lower than expected based on information appearing in the news media and EMS trade magazines. Findings provide estimates of two key workforce measures – turnover rates and costs – where previously none have existed. Local EMS directors and policymakers at all levels of government may find the results and study methodology useful towards designing and evaluating programs targeting the EMS workforce. PMID:20199235

Caregiving in a patient's place of residence: turnover of direct care workers in home care and hospice agencies.

PubMed

Dill, Janette S; Cagle, John

2010-09-01

High turnover and staff shortages among home care and hospice workers may compromise the quality and availability of in-home care. This study explores turnover rates of direct care workers for home care and hospice agencies. OLS (ordinary least square) regression models are run using organizational data from 93 home care agencies and 29 hospice agencies in North Carolina. Home care agencies have higher total turnover rates than hospice agencies, but profit status may be an important covariate. Higher unemployment rates are associated with lower voluntary turnover. Agencies that do not offer health benefits experience higher involuntary turnover. Differences in turnover between hospice and home health agencies suggest that organizational characteristics of hospice care contribute to lower turnover rates. However, the variation in turnover rates is not fully explained by the proposed multivariate models. Future research should explore individual and structural-level variables that affect voluntary and involuntary turnover in these settings.

The role of staff turnover in the implementation of evidence-based practices in mental health care.

PubMed

Woltmann, Emily M; Whitley, Rob; McHugo, Gregory J; Brunette, Mary; Torrey, William C; Coots, Laura; Lynde, David; Drake, Robert E

2008-07-01

This study examined turnover rates of teams implementing psychosocial evidence-based practices in public-sector mental health settings. It also explored the relationship between turnover and implementation outcomes in an effort to understand whether practitioner perspectives on turnover are related to implementation outcomes. Team turnover was measured for 42 implementing teams participating in a national demonstration project examining implementation of five evidence-based practices between 2002 and 2005. Regression techniques were used to analyze the effects of team turnover on penetration and fidelity. Qualitative data collected throughout the project were blended with the quantitative data to examine the significance of team turnover to those attempting to implement the practices. High team turnover was common (M+/-SD=81%+/-46%) and did not vary by practice. The 24-month turnover rate was inversely related to fidelity scores at 24 months (N=40, beta=-.005, p=.01). A negative trend was observed for penetration. Further analysis indicated that 71% of teams noted that turnover was a relevant factor in implementation. The behavioral health workforce remains in flux. High turnover most often had a negative impact on implementation, although some teams were able to use strategies to improve implementation through turnover. Implementation models must consider turbulent behavioral health workforce conditions.

ASSESSING THE TRAINING NEEDS WITHIN A FIRM (IN INDUSTRIAL TRAINING INTERNATIONAL, 2(9)/346-353, SEP 1967).

ERIC Educational Resources Information Center

1967

A CASE STUDY BY A SENIOR TRAINING OFFICER OF THE BRITISH ENGINEERING INDUSTRIAL TRAINING BOARD SHOWS WHY A FIRM MUST EXAMINE IN DETAIL A NUMBER OF FACTORS TO DETERMINE WHERE TO APPLY ITS TRAINING EFFORT. EXCESSIVE LABOR COSTS MAY BE ATTRIBUTED TO INADEQUATE OR INAPPROPRIATE INITIAL TRAINING, HIGH LABOR TURNOVER DUE TO LOW WAGES, ESTABLISHMENT OF…

Stayers, leavers, and switchers among certified nursing assistants in nursing homes: a longitudinal investigation of turnover intent, staff retention, and turnover.

PubMed

Rosen, Jules; Stiehl, Emily M; Mittal, Vikas; Leana, Carrie R

2011-10-01

Studies of certified nursing assistant (CNA) turnover in nursing homes are typically cross-sectional and include full-time and part-time workers. We conducted a longitudinal study to evaluate the job factors and work attitudes associated with just full-time staying or leaving. For those who did not stay, we assessed reasons for leaving and satisfaction following job transition. A random sample of CNAs identified through the Pennsylvania Department of Health's CNA registry, working ≥ 30 hr weekly in a nursing facility was surveyed by telephone at baseline and 1 year later. Of the 620 responding to both surveys, 532 (85.8%) remained (stayers), 52 (8.4%) switched to another facility (switchers), and 36 (5.8%) left the industry (leavers). At baseline, switchers reported higher turnover intentions and fewer benefits compared with stayers and left for new opportunities. Leavers had lower job satisfaction and emotional well-being and left for health reasons. Turnover intentions were predicted by low job satisfaction and low emotional well-being. Actual turnover was predicted only by turnover intentions and by the absence of health insurance. Pay was not a predictor of turnover intent or turnover. There are two distinct groups of CNAs contributing to turnover. Attitudinal factors, such as job satisfaction and emotional well-being, are mediated via turnover intentions to effect actual turnover. Even accounting for methodological differences, this turnover rate is lower than previous studies, which use alternative methods and include part-time workers. This study should help nursing home administrators better understand the work-related factors associated with staff turnover.

Workforce turnover at local health departments: nature, characteristics, and implications.

PubMed

Newman, Sarah J; Ye, Jiali; Leep, Carolyn J

2014-11-01

Employee turnover, defined as total separations from employment, is expensive, can result in lost capacity, and can limit local health departments' (LHDs') ability to respond to public health needs. Despite the importance of workforce capacity in public health, little is known about workforce turnover in LHDs. To examine the extent to which LHDs experience turnover and identify LHD characteristics that are associated with turnover. A cross-sectional data set of employee turnover and LHD characteristics from the 2013 National Profile of LHDs was analyzed. Descriptive statistics and bivariate analyses were conducted in 2014 on turnover rates. The effect of the following LHD characteristics on turnover rates were examined: population size, governance type, degree of urbanization, top executive experience level, expenditures per capita, and LHD budget cuts. In 2013, LHDs experienced a mean turnover rate of 9.88%; approximately one third of turnover was due to retirements. LHDs with shared state and local governance experienced a higher turnover rate than LHDs with exclusive state or local governance. LHDs that are units of state agencies had a significantly higher retirement rate than those governed by local authorities. Top executive experience level, per capita expenditures, and LHD budget cuts were also related to turnover rates. LHDs experienced a lower overall turnover rate than state health departments in 2011 and lower than all local and state government agencies in 2012. Strengthening leadership skills of new top executives and ensuring adequate funding may reduce turnover in LHDs. Copyright © 2014 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Revisiting the impact of job satisfaction and organizational commitment on nurse turnover intention: an individual differences analysis.

PubMed

De Gieter, Sara; Hofmans, Joeri; Pepermans, Roland

2011-12-01

Nurse turnover is an important contributing factor to the worldwide nursing shortage. Many studies have examined the antecedents of nurse turnover to gain a better understanding of the problem and help hospitals reduce their turnover rates. However, an important shortcoming of this research stream is its exclusive focus on explaining turnover behavior of the "average nurse", thereby disregarding individual differences between nurses and groups of nurses. To examine individual differences in the relationships between two crucial turnover antecedents - job satisfaction and organizational commitment - and nurse turnover intention. A sample of 287 nurses working for a variety of Belgian hospitals participated in the study. A survey method was used to collect quantitative data, which were analyzed through standard multiple linear regression, mixture regression models and t-tests. In the total sample of hospital nurses, both job satisfaction and organizational commitment significantly predicted nurse turnover intention. However, subsequent individual differences analyses revealed the existence of two subgroups of nurses. In the satisfaction focused group, only job satisfaction was found to predict nurse turnover intention, whereas in the satisfaction and commitment focused group both job satisfaction and organizational commitment were related to turnover intention. Furthermore, nurses in the latter group displayed stronger turnover intention, were significantly younger and had less job tenure and organizational tenure than nurses in the satisfaction focused group. The debate on the antecedents of nurse turnover still continues, as the existing models fail to fully grasp nurse turnover. The present study identifies individual differences in nurse turnover antecedents among groups of nurses as a possible reason for the absence of one comprehensive turnover model that holds for the general nursing population. Further studies are needed in order to capture the total impact of the underlying individual differences in nurse turnover antecedents. 2011 Elsevier Ltd. All rights reserved.

Effects of chronic administration of nicotine on storage and synthesis of noradrenaline in rat brain

PubMed Central

Bhagat, B.

1970-01-01

1. Chronic administration of nicotine (0·5 mg/kg, subcutaneously four times a day, 5 days a week, for 6 weeks) did not affect the growth rate and water intake in rats. In these animals food intake was normal for the first 5 weeks, but was significantly increased during the sixth week of treatment. 2. Nicotine administration increased the blood pressure of rats from 120 mm Hg to 151 mm Hg. 3. The concentrations of endogenous noradrenaline, dopamine, 5-hydroxytryptamine and acetylcholine in the brain remained unaltered. However, chronic treatment with nicotine increased the turnover rate of noradrenaline. Initial accumulation of 3H-noradrenaline was also significantly increased. 4. It is concluded from these studies that changes in the turnover of cerebral noradrenaline caused by chronic administration rather than changes in the concentration of noradrenaline may be an important factor in nicotine-induced behavioural changes. PMID:5413293

Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion

ERIC Educational Resources Information Center

Hom, Peter W.; Mitchell, Terence R.; Lee, Thomas W.; Griffeth, Rodger W.

2012-01-01

We reconceptualize employee turnover to promote researchers' understanding and prediction of why employees quit or stay in employing institutions. A literature review identifies shortcomings with prevailing turnover dimensions. In response, we expand the conceptual domain of the turnover criterion to include multiple types of turnover (notably,…

Work and Career considerations in Understanding Employee Turnover Intentions and Turnover: Development of the Turnover Diagnostic.

DTIC Science & Technology

1984-08-01

speciflying some of these factor. Employee Turnover 22 References Alderfer , C . P., & Brown, L. D. (1972). Designing an "empathic questionnaire" for...organizational research. Journal of Applied Psychology 5 456-460. Alley, W. E ., & Gould, R . B. (1975). Feasibility of estimating personnel turnover from...leadership behavior related to employee grievances and turnover. Personnel Psychology, 15 43-56. Forrest, C . R ., Cummings, L. L., & Johnson, A. C

The effect of culture on the curvilinear relationship between performance and turnover.

PubMed

Sturman, Michael C; Shao, Lian; Katz, Jan H

2012-01-01

Although researchers have theorized that there exists a curvilinear relationship between job performance and voluntary turnover, their research has been tested in the United States or culturally similar Switzerland. Through a study of the performance-turnover relationship from a multinational service-oriented organization in 24 countries, we demonstrate that the general relationship between performance and turnover is similar across countries but the details of that relationship change across countries. Using 4 cultural dimensions--in-group collectivism, power distance, uncertainty avoidance, and performance orientation--we find that cultural factors alter the overall probability of voluntary turnover and influence the degree of curvilinearity in the performance-turnover relationship. Our findings have implications for research on the performance-turnover relationship, turnover research, and practice.

Analysis and control of employee turnover.

PubMed

McConnell, Charles R

2007-01-01

Turnover is a relatively simple and easily described concept. However, considerable confusion often results when addressing turnover because of differences in how it is defined; that is, what is counted, how it is counted, and how the turnover rates are expressed. Turnover is also costly, although not enough attention is paid to its cost because so much of it is indirect, and thus, not readily visible. There are a variety of causes of turnover, some which can be corrected and some which cannot be avoided. Reducing or otherwise controlling turnover requires continuing management attention to its causes and constant recognition of what can and should be controlled and what cannot be controlled. Ongoing attention to turnover is an essential part of the department manager's role.

Changes of Protein Turnover in Aging Caenorhabditis elegans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhondt, Ineke; Petyuk, Vladislav A.; Bauer, Sophie

Protein turnover rates severely decline in aging organisms, including C. elegans. However, limited information is available on turnover dynamics at the individual protein level during aging. We followed changes in protein turnover at one-day resolution using a multiple-pulse 15Nlabeling and accurate mass spectrometry approach. Forty percent of the proteome shows gradual slowdown in turnover with age, whereas only few proteins show increased turnover. Decrease in protein turnover was consistent for only a minority of functionally related protein subsets, including tubulins and vitellogenins, whereas randomly diverging turnover patterns with age were the norm. Our data suggests increased heterogeneity of protein turnovermore » of the translation machinery, whereas protein turnover of ubiquitin-proteasome and antioxidant systems are well-preserved over time. Hence, we presume that maintenance of quality control mechanisms is a protective strategy in aging worms, although the ultimate proteome collapse is inescapable.« less

Turnover in health care: the mediating effects of employee engagement.

PubMed

Collini, Stevie A; Guidroz, Ashley M; Perez, Lisa M

2015-03-01

This study aimed to understand the interaction between interpersonal respect, diversity climate, mission fulfilment and engagement to better predict turnover in health care. Registered nurse turnover has averaged 14% and current nursing shortages are expected to spread. Few studies have studied employee engagement as a mediator between organisational context and turnover. Study participants were employees working within 185 departments across ten hospitals within a large healthcare organisation in the USA. Although a total of 5443 employees work in these departments, employee opinion survey responses were aggregated by department before being linked to turnover rates gathered from company records. Engagement fully mediated the relationship between respect and turnover and the relationship between mission fulfilment and turnover. Diversity climate was not related to turnover. Turnover in health care poses a significant threat to the mission of creating a healing environment for patients and these results demonstrate that workplace respect and connection to the mission affect turnover by decreasing engagement. The findings demonstrated that to increase engagement, and improve turnover rates in health care, it would be beneficial for organisations, and nurse management to focus on improving mission fulfilment and interpersonal relationships. © 2013 John Wiley & Sons Ltd.

Predictors of actual turnover in a national sample of newly licensed registered nurses employed in hospitals.

PubMed

Brewer, Carol S; Kovner, Christine T; Greene, William; Tukov-Shuser, Magdalene; Djukic, Maja

2012-03-01

This paper is a report of a study of factors that affect turnover of newly licensed registered nurses in United States hospitals. There is a large body of research related to nursing retention; however, there is little information specific to newly licensed registered nurse turnover. Incidence rates of turnover among new nurses are unknown because most turnover data are not from nationally representative samples of nurses. This study used a longitudinal panel design to obtain data from 1653 registered nurses who were recently licensed by examination for the first time. We mailed surveys to a nationally representative sample of hospital registered nurses 1 year apart. The analytic sample consisted of 1653 nurses who responded to both survey mailings in January of 2006 and 2007. Full-time employment and more sprains and strains (including back injuries) result in more turnover. Higher intent to stay and hours of voluntary overtime and more than one job for pay reduces turnover. When we omitted intent to stay from the probit model, less job satisfaction and organizational commitment led to more turnover, confirming their importance to turnover. Magnet Recognition Award(®) hospitals and several other work attributes had no effect on turnover.   Turnover problems are complex, which means that there is no one solution to decreasing turnover. Multiple points of intervention exist. One specific approach that may improve turnover rates is hospital policies that reduce strains and sprains. © 2011 The Authors. Journal of Advanced Nursing © 2011 Blackwell Publishing Ltd.

Characterization of the mammalian miRNA turnover landscape

PubMed Central

Guo, Yanwen; Liu, Jun; Elfenbein, Sarah J.; Ma, Yinghong; Zhong, Mei; Qiu, Caihong; Ding, Ye; Lu, Jun

2015-01-01

Steady state cellular microRNA (miRNA) levels represent the balance between miRNA biogenesis and turnover. The kinetics and sequence determinants of mammalian miRNA turnover during and after miRNA maturation are not fully understood. Through a large-scale study on mammalian miRNA turnover, we report the co-existence of multiple cellular miRNA pools with distinct turnover kinetics and biogenesis properties and reveal previously unrecognized sequence features for fast turnover miRNAs. We measured miRNA turnover rates in eight mammalian cell types with a combination of expression profiling and deep sequencing. While most miRNAs are stable, a subset of miRNAs, mostly miRNA*s, turnovers quickly, many of which display a two-step turnover kinetics. Moreover, different sequence isoforms of the same miRNA can possess vastly different turnover rates. Fast turnover miRNA isoforms are enriched for 5′ nucleotide bias against Argonaute-(AGO)-loading, but also additional 3′ and central sequence features. Modeling based on two fast turnover miRNA*s miR-222-5p and miR-125b-1-3p, we unexpectedly found that while both miRNA*s are associated with AGO, they strongly differ in HSP90 association and sensitivity to HSP90 inhibition. Our data characterize the landscape of genome-wide miRNA turnover in cultured mammalian cells and reveal differential HSP90 requirements for different miRNA*s. Our findings also implicate rules for designing stable small RNAs, such as siRNAs. PMID:25653157

The Role of Organizational Culture in Retaining Nursing Workforce

PubMed Central

Banaszak-Holl, Jane; Castle, Nicholas G.; Lin, Michael K.; Shrivastwa, Nijika; Spreitzer, Gretchen

2015-01-01

Purpose of the Study: We examined how organizational culture in nursing homes affects staff turnover, because culture is a first step to creating satisfactory work environments. Design and Methods: Nursing home administrators were asked in 2009 to report on facility culture and staff turnover. We received responses from 419 of 1,056 administrators contacted. Respondents reported the strength of cultural values using scales from a Competing Values Framework and percent of staff leaving annually for Registered Nurse (RN), Licensed Practice Nurse (LPN), and nursing aide (NA) staff. We estimated negative binomial models predicting turnover.  Results: Turnover rates are lower than found in past but remain significantly higher among NAs than among RNs or LPNs. Facilities with stronger market values had increased turnover among RNs and LPNs, and among NAs when turnover was adjusted for facilities with few staff. Facilities emphasizing hierarchical internal processes had lower RN turnover. Group and developmental values focusing on staff and innovation only lowered LPN turnover. Finally, effects on NA turnover become insignificant when turnover was adjusted if voluntary turnover was reported. Implications: Organizational culture had differential effects on the turnover of RN, LPN, and NA staff that should be addressed in developing culture-change strategies. More flexible organizational culture values were important for LPN staff only, whereas unexpectedly, greater emphasis on rigid internal rules helped facilities retain RNs. Facilities with a stronger focus on customer needs had higher turnover among all staff. PMID:24218146

Stayers, Leavers, and Switchers Among Certified Nursing Assistants in Nursing Homes: A Longitudinal Investigation of Turnover Intent, Staff Retention, and Turnover

PubMed Central

Rosen, Jules

2011-01-01

Purpose: Studies of certified nursing assistant (CNA) turnover in nursing homes are typically cross-sectional and include full-time and part-time workers. We conducted a longitudinal study to evaluate the job factors and work attitudes associated with just full-time staying or leaving. For those who did not stay, we assessed reasons for leaving and satisfaction following job transition. Design and Methods: A random sample of CNAs identified through the Pennsylvania Department of Health's CNA registry, working≥30 hr weekly in a nursing facility was surveyed by telephone at baseline and 1 year later. Results: Of the 620 responding to both surveys, 532 (85.8%) remained (stayers), 52 (8.4%) switched to another facility (switchers), and 36 (5.8%) left the industry (leavers). At baseline, switchers reported higher turnover intentions and fewer benefits compared with stayers and left for new opportunities. Leavers had lower job satisfaction and emotional well-being and left for health reasons. Turnover intentions were predicted by low job satisfaction and low emotional well-being. Actual turnover was predicted only by turnover intentions and by the absence of health insurance. Pay was not a predictor of turnover intent or turnover. Implications: There are two distinct groups of CNAs contributing to turnover. Attitudinal factors, such as job satisfaction and emotional well-being, are mediated via turnover intentions to effect actual turnover. Even accounting for methodological differences, this turnover rate is lower than previous studies, which use alternative methods and include part-time workers. This study should help nursing home administrators better understand the work-related factors associated with staff turnover. PMID:21498629

Quantifying high resolution transitional breaks in plant and mammal distributions at regional extent and their association with climate, topography and geology.

PubMed

Di Virgilio, Giovanni; Laffan, Shawn W; Ebach, Malte C

2013-01-01

We quantify spatial turnover in communities of 1939 plant and 59 mammal species at 2.5 km resolution across a topographically heterogeneous region in south-eastern Australia to identify distributional breaks and low turnover zones where multiple species distributions overlap. Environmental turnover is measured to determine how climate, topography and geology influence biotic turnover differently across a variety of biogeographic breaks and overlaps. We identify the genera driving turnover and confirm the versatility of this approach across spatial scales and locations. Directional moving window analyses, rotated through 360°, were used to measure spatial turnover variation in different directions between gridded cells containing georeferenced plant and mammal occurrences and environmental variables. Generalised linear models were used to compare taxic turnover results with equivalent analyses for geology, regolith weathering, elevation, slope, solar radiation, annual precipitation and annual mean temperature, both uniformly across the entire study area and by stratifying it into zones of high and low turnover. Identified breaks and transitions were compared to a conservation bioregionalisation framework widely used in Australia. Detailed delineations of plant and mammal turnover zones with gradational boundaries denoted subtle variation in species assemblages. Turnover patterns often diverged from bioregion boundaries, though plant turnover adhered most closely. A prominent break zone contained either comparable or greater numbers of unique genera than adjacent overlaps, but these were concentrated in a small subsection relatively under-protected by conservation reserves. The environmental correlates of biotic turnover varied for different turnover zones in different subsections of the study area. Topography and temperature showed much stronger relationships with plant turnover in a topographically complex overlap, relative to a lowland overlap where weathering was most predictive. This method can quantify transitional turnover patterns from small to broad extents, at different resolutions for any location, and complements broad-scale bioregionalisation schemes in conservation planning.

Turnover-Dependent Inactivation of the Nitrogenase MoFe-Protein at High pH

PubMed Central

2013-01-01

Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725–13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis. PMID:24392967

Turnover-dependent inactivation of the nitrogenase MoFe-protein at high pH.

PubMed

Yang, Kun-Yun; Haynes, Chad A; Spatzal, Thomas; Rees, Douglas C; Howard, James B

2014-01-21

Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725-13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis.

Fluorophotometric measurement of the buffering action of human tears in vivo.

PubMed

Yamada, M; Kawai, M; Mochizuki, H; Hata, Y; Mashima, Y

1998-10-01

The buffering action of human tears is thought to be important to keep its pH constant. We measured the change in pH in the precorneal tear film in vivo when the acidic solution is challenged, using a fluorophotometric technique. Twelve eyes from 6 healthy subjects were entered in this study. Each subject was pretreated with either one drop of 0.4% oxybuprocaine for once (light anesthesia), three times (deep anesthesia), or none (controls). The measurement was initiated by instilling 20 microl of 0.067 M phosphate buffer at pH 5.5 containing 2 mM bis-carboxyethyl-carboxyfluorescein free acid, a pH sensitive dye, into the subject's eye. The pH was determined by the ratio of fluorescent intensities at two excitation wavelengths (490 and 430 nm). pH recovery time (PHRT) as defined by the time required for pH to reach 95% of pH at equilibrium was used for the marker of tear buffering action. Tear turnover rate was also determined using the fluorescent decay curve at 430 nm, which was independent of pH, but dependent on dye concentration. Immediately after the instillation, the pH value in the tear film was around 6.0-6.5 in all cases. The tear film rapidly became more alkaline, reaching its normal value in 2.3 +/- 0.5 min in untreated eyes. The pretreatment with 0.4% oxybuprocaine retarded the neutralization process. A single regression analysis revealed that the PHRT had a significant negative correlation with the tear turnover rate (r = -0.78). Our results suggest that the neutralization process of tears largely depends on the tear turnover rate. The buffering action of tears in vivo consists of the tear turnover as well as its chemical buffering capacity.

The rate and cost of nurse turnover in Australia.

PubMed

Roche, Michael A; Duffield, Christine M; Homer, Caroline; Buchan, James; Dimitrelis, Sofia

2015-01-01

Nurse turnover is a critical issue facing workforce planners across the globe, particularly in light of protracted and continuing workforce shortages. An ageing population coupled with the rise in complex and chronic diseases, have contributed to increased demands placed on the health system and importantly, nurses who themselves are ageing. Costs associated with nurse turnover are attracting more attention; however, existing measurements of turnover show inconsistent findings, which can be attributed to differences in study design, metrics used to calculate turnover and variations in definitions for turnover. This paper will report the rates and costs of nurse turnover across three States in Australia.

Turnover and organizational performance: a comparative analysis of the effects of voluntary, involuntary, and reduction-in-force turnover.

PubMed

McElroy, J C; Morrow, P C; Rude, S N

2001-12-01

Data were collected from 31 regional subunits of a national financial services company to examine differential effects of 3 types of turnover (voluntary, involuntary, and reduction-in-force) on measures of organizational subunit performance. Although each form of turnover exhibited adverse effects on subunit performance when examined separately, partial correlation results revealed greater and more pervasive adverse effects for reduction-in-force turnover (i.e., downsizing) in comparison with the effects of voluntary and involuntary turnover. The results confirm the negative effects of downsizing, suggesting the need to move beyond the traditional voluntary-involuntary classification scheme used in turnover research.

Effects of work environment and job characteristics on the turnover intention of experienced nurses: The mediating role of work engagement.

PubMed

Wan, Qiaoqin; Li, Zhaoyang; Zhou, Weijiao; Shang, Shaomei

2018-06-01

To assess turnover intention among experienced nurses and explore the effects of work environment, job characteristics and work engagement on turnover intention. The nursing shortage is an urgent concern in China. A high turnover rate of experienced nurses could have serious effects on the quality of care, costs and the efficiency of hospitals. It is crucial to explore the predictors of turnover intention and develop strategies tailored to experienced nurses. A descriptive, cross-sectional survey design. A total of 778 experienced nurses from seven hospitals was surveyed on their work engagement, job characteristics, work environment and turnover intention in March-May 2017. Structural equation modelling was used to test a theoretical model and the hypotheses. The results showed that 35.9% of experienced nurses had high-level turnover intention. The final model explained 50% of the variance in experienced nurses' turnover intention and demonstrated that: (1) work environment was positively associated with higher work engagement and lower turnover intention and work engagement partially mediated the relationship between work environment and turnover intention; and (2) job characteristics were positively related to higher work engagement and lower turnover intention and work engagement fully mediated the relationship between job characteristics and turnover intention. The study confirms the intrinsic and extrinsic motivators on work engagement posited by job demands-resources model. Theory-driven strategies to improve work environment, enhance job characteristics and promote wok engagement are needed to address the nursing shortage and high turnover intention among experienced nurses. © 2018 John Wiley & Sons Ltd.

The role of organizational culture in retaining nursing workforce.

PubMed

Banaszak-Holl, Jane; Castle, Nicholas G; Lin, Michael K; Shrivastwa, Nijika; Spreitzer, Gretchen

2015-06-01

We examined how organizational culture in nursing homes affects staff turnover, because culture is a first step to creating satisfactory work environments. Nursing home administrators were asked in 2009 to report on facility culture and staff turnover. We received responses from 419 of 1,056 administrators contacted. Respondents reported the strength of cultural values using scales from a Competing Values Framework and percent of staff leaving annually for Registered Nurse (RN), Licensed Practice Nurse (LPN), and nursing aide (NA) staff. We estimated negative binomial models predicting turnover.  Turnover rates are lower than found in past but remain significantly higher among NAs than among RNs or LPNs. Facilities with stronger market values had increased turnover among RNs and LPNs, and among NAs when turnover was adjusted for facilities with few staff. Facilities emphasizing hierarchical internal processes had lower RN turnover. Group and developmental values focusing on staff and innovation only lowered LPN turnover. Finally, effects on NA turnover become insignificant when turnover was adjusted if voluntary turnover was reported. Organizational culture had differential effects on the turnover of RN, LPN, and NA staff that should be addressed in developing culture-change strategies. More flexible organizational culture values were important for LPN staff only, whereas unexpectedly, greater emphasis on rigid internal rules helped facilities retain RNs. Facilities with a stronger focus on customer needs had higher turnover among all staff. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effect of acute millimeter wave exposure on dopamine metabolism of NGF-treated PC12 cells.

PubMed

Haas, Alexis J; Le Page, Yann; Zhadobov, Maxim; Sauleau, Ronan; Dréan, Yves Le; Saligaut, Christian

2017-07-01

Several forthcoming wireless telecommunication systems will use electromagnetic frequencies at millimeter waves (MMWs), and technologies developed around the 60-GHz band will soon know a widespread distribution. Free nerve endings within the skin have been suggested to be the targets of MMW therapy which has been used in the former Soviet Union. So far, no studies have assessed the impact of MMW exposure on neuronal metabolism. Here, we investigated the effects of a 24-h MMW exposure at 60.4 GHz, with an incident power density (IPD) of 5 mW/cm², on the dopaminergic turnover of NGF-treated PC12 cells. After MMW exposure, both intracellular and extracellular contents of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were studied using high performance liquid chromatography. Impact of exposure on the dopamine transporter (DAT) expression was also assessed by immunocytochemistry. We analyzed the dopamine turnover by assessing the ratio of DOPAC to DA, and measuring DOPAC accumulation in the medium. Neither dopamine turnover nor DAT protein expression level were impacted by MMW exposure. However, extracellular accumulation of DOPAC was found to be slightly increased, but not significantly. This result was related to the thermal effect, and overall, no evidence of non-thermal effects of MMW exposure were observed on dopamine metabolism. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Promoting retention of nurses: A meta-analytic examination of causes of nurse turnover.

PubMed

Nei, Darin; Snyder, Lori Anderson; Litwiller, Brett J

2015-01-01

Because the health care field is expected to be the fastest growing job field until 2020, an urgent need to focus on nurse retention exists. The aim of this study was to examine the relationships between predictors of turnover (i.e., personal characteristics, role states, job characteristics, group/leader relations, organizational/environmental perceptions, attitudinal reactions) and turnover cognitions and intentions, as well as actual turnover among nurses, in an effort to determine the strongest predictors of voluntary turnover. Meta-analysis was used to determine best estimates of the effect of predictors on turnover based on 106 primary studies of employed nurses. Meta-analyzed correlations were subjected to path analysis to establish the structural relationships among the study variables. Supportive and communicative leadership, network centrality, and organizational commitment are the strongest predictors of voluntary turnover based on meta-analytic correlations. Additional variables that relate to nurse turnover intentions include job strain, role tension, work-family conflict, job control, job complexity, rewards/recognition, and team cohesion. The findings suggest that some factors, such as salary, are relatively less important in prediction of turnover. Administrators concerned about nurse turnover may more effectively direct resources toward altering certain job characteristics and work conditions in the effort to reduce voluntary turnover among nurses.

Impact and determinants of nurse turnover: a pan-Canadian study.

PubMed

O'Brien-Pallas, Linda; Murphy, Gail Tomblin; Shamian, Judith; Li, Xiaoqiang; Hayes, Laureen J

2010-11-01

As part of a large study of nursing turnover in Canadian hospitals, the present study focuses on the impact and key determinants of nurse turnover and implications for management strategies in nursing units. Nursing turnover is an issue of ever-increasing priority as work-related stress and job dissatisfaction are influencing nurses' intention to leave their positions. Data sources included the nurse survey, unit managers, medical records and human resources databases. A broad sample of hospitals was represented with nine different types of nursing units included. Nurses turnover is a major problem in Canadian hospitals with a mean turnover rate of 19.9%. Higher levels of role ambiguity and role conflict were associated with higher turnover rates. Increased role conflict and higher turnover rates were associated with deteriorated mental health. Higher turnover rates were associated with lower job satisfaction. Higher turnover rate and higher level of role ambiguity were associated with an increased likelihood of medical error. Managing turnover within nursing units is critical to high-quality patient care. A supportive practice setting in which role responsibilities are understood by all members of the caregiver team would promote nurse retention. Stable nurse staffing and adequate managerial support are essential to promote job satisfaction and high-quality patient care. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

Rethinking Teacher Turnover: Longitudinal Measures of Instability in Schools

ERIC Educational Resources Information Center

Holme, Jennifer Jellison; Jabbar, Huriya; Germain, Emily; Dinning, John

2018-01-01

While there is a robust literature examining the patterns and causes of teacher turnover, few articles to date have critically examined the measures of turnover used in these studies. Yet, an assessment of the way turnover is measured is important, as the measures become the means by which the "problem" of turnover becomes defined and…

Explaining the Gap in Charter and Traditional Public School Teacher Turnover Rates

ERIC Educational Resources Information Center

Stuit, David A.; Smith, Thomas M.

2012-01-01

This study uses national survey data to examine why charter school teachers are more likely to turnover than their traditional public school counterparts. We test whether the turnover gap is explained by different distributions of factors that are empirically and theoretically linked to turnover risk. We find that the turnover rate of charter…

Communication: Relaxation-limited electronic currents in extended reservoir simulations

NASA Astrophysics Data System (ADS)

Gruss, Daniel; Smolyanitsky, Alex; Zwolak, Michael

2017-10-01

Open-system approaches are gaining traction in the simulation of charge transport in nanoscale and molecular electronic devices. In particular, "extended reservoir" simulations, where explicit reservoir degrees of freedom are present, allow for the computation of both real-time and steady-state properties but require relaxation of the extended reservoirs. The strength of this relaxation, γ, influences the conductance, giving rise to a "turnover" behavior analogous to Kramers turnover in chemical reaction rates. We derive explicit, general expressions for the weak and strong relaxation limits. For weak relaxation, the conductance increases linearly with γ and every electronic state of the total explicit system contributes to the electronic current according to its "reduced" weight in the two extended reservoir regions. Essentially, this represents two conductors in series—one at each interface with the implicit reservoirs that provide the relaxation. For strong relaxation, a "dual" expression-one with the same functional form-results, except now proportional to 1/γ and dependent on the system of interest's electronic states, reflecting that the strong relaxation is localizing electrons in the extended reservoirs. Higher order behavior (e.g., γ2 or 1/γ2) can occur when there is a gap in the frequency spectrum. Moreover, inhomogeneity in the frequency spacing can give rise to a pseudo-plateau regime. These findings yield a physically motivated approach to diagnosing numerical simulations and understanding the influence of relaxation, and we examine their occurrence in both simple models and a realistic, fluctuating graphene nanoribbon.

Impact of a Pay-for-Performance Program on Care for Black Patients with Hypertension: Important Answers in the Era of the Affordable Care Act.

PubMed

Petersen, Laura A; Ramos, Kate Simpson; Pietz, Kenneth; Woodard, LeChauncy D

2017-06-01

Evaluate the effect of a pay-for-performance intervention on the quality of hypertension care provided to black patients and determine whether it produced risk selection. Primary data collected between 2007 and 2009 from Veterans Affairs physicians and their primary care panels. Nested study within a cluster randomized controlled trial of three types of financial incentives and no incentives (control). We compared the proportion of physicians' black patients meeting hypertension performance measures for baseline and final performance periods. We measured risk selection by comparing the proportion of patients who switched providers, patient visit frequency, and panel turnover. Due to limited power, we prespecified in the analysis plan combining the three incentive groups and oversampling black patients. Data collected electronically and by chart review. The proportion of black patients who achieved blood pressure control or received an appropriate response to uncontrolled blood pressure in the final period was 6.3 percent (95 percent confidence interval, 0.8-11.7 percent) greater for physicians who received an incentive than for controls. There was no difference between intervention and controls in the proportion of patients who switched providers, visit frequency, or panel turnover. A pay-for-performance intervention improved blood pressure control or appropriate response to uncontrolled blood pressure in black patients and did not produce risk selection. © Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Horizontal and vertical species turnover in tropical birds in habitats with differing land use.

PubMed

Sreekar, Rachakonda; Corlett, Richard T; Dayananda, Salindra; Goodale, Uromi Manage; Kilpatrick, Adam; Kotagama, Sarath W; Koh, Lian Pin; Goodale, Eben

2017-05-01

Large tracts of tropical rainforests are being converted into intensive agricultural lands. Such anthropogenic disturbances are known to reduce species turnover across horizontal distances. But it is not known if they can also reduce species turnover across vertical distances (elevation), which have steeper climatic differences. We measured turnover in birds across horizontal and vertical sampling transects in three land-use types of Sri Lanka: protected forest, reserve buffer and intensive-agriculture, from 90 to 2100 m a.s.l. Bird turnover rates across horizontal distances were similar across all habitats, and much less than vertical turnover rates. Vertical turnover rates were not similar across habitats. Forest had higher turnover rates than the other two habitats for all bird species. Buffer and intensive-agriculture had similar turnover rates, even though buffer habitats were situated at the forest edge. Therefore, our results demonstrate the crucial importance of conserving primary forest across the full elevational range available. © 2017 The Author(s).

How hospitals view unit-level nurse turnover data collection: analysis of a hospital survey.

PubMed

Park, Shin Hye; Boyle, Diane K

2015-02-01

The objectives of this study were to examine the quality of unit-level nurse turnover data collection among the National Database of Nursing Quality Indicators hospitals and to identify the burdens of collecting such data. Tracking and managing nurse turnover at the unit level are critical for administrators who determine managerial strategies. Little is known about the quality of and burdens of unit-level turnover data collection. Surveys from 178 hospitals were analyzed descriptively. Most hospitals strongly agreed or agreed with the quality of unit-level turnover data collection. Hospitals identified the burdens of additional time and resources needed for unit-level turnover data collection and the difficulty of obtaining specific reasons for turnover. Collecting unit-level nurse turnover data can be important and useful for administrators to improve nurse retention, workforce stability, and quality of care. We suggest that the advantages of unit-level nurse turnover data and reports can overcome the identified burdens.

Nurse turnover in the Kingdom of Saudi Arabia: An integrative review.

PubMed

Falatah, Rawaih; Salem, Olfat A

2018-04-06

To appraise and synthesise existing literature on nurse turnover in the Saudi Arabian context. Saudi Arabia is notably one of the nations with a health care system that is bombarded by high rates of turnover and turnover intention. Moreover, rapid population growth and the expansion of the health care system increase the demand on registered nurses in the kingdom. Eleven primary sources were reviewed using Whittemore and Knafl's (Journal of Advanced Nursing, 2005; 52, 546-553) integrative review method. There is variation in the reported turnover rates across the studies. The identified determinants of nurse turnover in the Saudi Arabian context included nurses' demographics, satisfaction, leadership and management, and job-related factors. There is a need for more studies that focus on the cost and outcome of nurse turnover and turnover intention in the Saudi Arabian context. The review highlights the alarming rates of nurse turnover and its determinants in Saudi Arabia. Nurse managers in Saudi Arabia should consider this information, as they make daily assignments. © 2018 John Wiley & Sons Ltd.

2014 Center for Army Leadership Annual Survey of Army Leadership (CASAL): Army Civilian Leader Findings

DTIC Science & Technology

2015-06-01

at preparing them for future responsibilities. Engagement is a measure of initiative and productivity . It is highest among civilian leaders but is at...are reported to exhibit counter- productive or negative leadership behaviors such as berating subordinates for small mistakes (15%), blaming other...outcomes (e.g., employee satisfaction, motivation, job performance) and organizational outcomes (e.g., turnover and absenteeism ). CASAL results

"Who Stays and Who Leaves?" Findings from a Three-Part Study of Teacher Turnover in NYC Middle Schools. Synthesis Report

ERIC Educational Resources Information Center

Marinell, William H.; Coca, Vanessa M.; Arum, Richard; Goldstein, Jennifer; Kemple, James; Pallas, Aaron; Bristol, Travis; Buckley, Clare; Scallon, Amy; Tanner, Barbara

2013-01-01

There is growing evidence that the middle school years are critical to students' long-term success. In New York City, middle schools have been the target of several high-profile improvement initiatives. One factor that has the potential to facilitate or complicate these efforts is the stability of the middle school teaching force. Yet there have…

Discovery, clinical development, and therapeutic uses of bisphosphonates.

PubMed

Licata, Angelo A

2005-04-01

To review the literature concerning the history, development, and therapeutic uses of bisphosphonates. English-language articles were identified through a search of MEDLINE (through December 2004) using the key word bisphosphonate. Reference lists of pivotal studies, reviews, and full prescribing information for the approved agents were also examined. Selected studies included those that discussed the discovery and initial applications of bisphosphonates, as well as their historical development, pharmacokinetic and pharmacodynamic properties, and current therapeutic uses. Bisphosphonates structurally resemble pyrophosphates (naturally occurring polyphosphates) and have demonstrated similar physicochemical effects to pyrophosphates. In addition, bisphosphonates reduce bone turnover and resist hydrolysis when administered orally. The information gained from initial work with etidronate generated a considerable scientific effort to design new and more effective bisphosphonates. The PCP moiety in the general bisphosphonate structure is essential for binding to hydroxyapatite and allows for a number of chemical variations by changing the 2 lateral side chains (designated R(1) and R(2)). The R(1) side chain determines binding affinity to hydroxyapatite, and the R(2) side chain determines antiresorptive potency. Accordingly, each bisphosphonate has its own characteristic profile of activity. The bisphosphonates reduce bone turnover, increase bone mass, and decrease fracture risk and therefore have a significant place in the management of skeletal disorders including osteoporosis, Paget's disease, bone metastases, osteogenesis imperfecta, and heterotopic ossification.

[New nurse turnover intention and influencing factors].

PubMed

Han, Sang Sook; Sohn, In Soon; Kim, Nam Eun

2009-12-01

The study was done to identify turnover intention in new nurses according to characteristics of the nurses and other factors affecting turnover and to provide data to set up a strategy to reduce the turnover. Data were collected from 1,077 new nurses who had less than 12 months employment experience and worked in one of 188 hospitals. Eight research instruments were used. Data analysis was done using SPSS WIN 15.0 program. Several factors influence new nurse turnover intention. The average score for turnover intention was 2.12. The scores for subscales were self efficacy, 3.76, nursing performance, 3.90, job satisfaction, 2.09, organization commitment, 1.28, stress, 1.32, burnout, 2.82 and nursing organizational culture, 3.29. Turnover intention was related to self efficacy, nursing performance, job satisfaction, organization commitment, stress, burnout, nursing organizational culture, duration of in-class training, duration of on the job training, number of hospital beds, length of employment and duration of employment in current workplace. The predicting factors for turnover intention were burnout, stress, duration of employment in the current workplace, self efficacy and nursing performance. Those factors explained 51.6% of turnover intention. New nurse turnover intention can be reduced by mitigating the factors affecting this intention.

Explaining turnover intention in Korean public community hospitals: occupational differences.

PubMed

Hwang, Jee-In; Chang, Hyejung

2008-01-01

Personnel in public hospitals had relatively low job satisfaction despite of tenure employment. High turnover rates degrade hospital image and incur additional costs related to recruitment and training. The purposes of this study were to describe the occupational differences and to identify factors affecting turnover intention among public hospital personnel. A questionnaire survey was conducted as part of Administrative Services Quality Evaluation Program by Seoul metropolitan municipality from 1 November to 1 December in 2003. The subjects were 1251 entire hospital personnel in four hospitals. The questionnaire was designed to measure job satisfaction, organizational commitment, turnover intention, and demographic characteristics. Logistic regression analysis was performed to determine factors influencing turnover intention. There were significant differences in job satisfaction, organizational commitment, and turnover intention according to the occupations. The turnover intention rates were highest among physicians, followed by paramedicals and nursing staffs and then administrators. The significant factors affecting turnover intention were involvement and loyalty among physicians, hospital type, satisfaction with systems and loyalty among nursing staffs, satisfaction with relationship and loyalty among administrators, and loyalty among paramedicals. There were different moderators that influence turnover intentions of hospital personnel. Loyalty had the most important effect upon turnover intention in all occupations. 2007 John Wiley & Sons, Ltd

Host associations and turnover of haemosporidian parasites in manakins (Aves: Pipridae).

PubMed

Fecchio, Alan; Svensson-Coelho, Maria; Bell, Jeffrey; Ellis, Vincenzo A; Medeiros, Matthew C; Trisos, Christopher H; Blake, John G; Loiselle, Bette A; Tobias, Joseph A; Fanti, Rebeka; Coffey, Elyse D; DE Faria, Iubatã P; Pinho, João B; Felix, Gabriel; Braga, Erika M; Anciães, Marina; Tkach, Vasyl; Bates, John; Witt, Christopher; Weckstein, Jason D; Ricklefs, Robert E; Farias, Izeni P

2017-06-01

Parasites of the genera Plasmodium and Haemoproteus (Apicomplexa: Haemosporida) are a diverse group of pathogens that infect birds nearly worldwide. Despite their ubiquity, the ecological and evolutionary factors that shape the diversity and distribution of these protozoan parasites among avian communities and geographic regions are poorly understood. Based on a survey throughout the Neotropics of the haemosporidian parasites infecting manakins (Pipridae), a family of Passerine birds endemic to this region, we asked whether host relatedness, ecological similarity and geographic proximity structure parasite turnover between manakin species and local manakin assemblages. We used molecular methods to screen 1343 individuals of 30 manakin species for the presence of parasites. We found no significant correlations between manakin parasite lineage turnover and both manakin species turnover and geographic distance. Climate differences, species turnover in the larger bird community and parasite lineage turnover in non-manakin hosts did not correlate with manakin parasite lineage turnover. We also found no evidence that manakin parasite lineage turnover among host species correlates with range overlap and genetic divergence among hosts. Our analyses indicate that host switching (turnover among host species) and dispersal (turnover among locations) of haemosporidian parasites in manakins are not constrained at this scale.

Predictors of Staff Turnover and Turnover Intentions within Addiction Treatment Settings: Change Over Time Matters.

PubMed

Garner, Bryan R; Hunter, Brooke D

2014-01-01

This study examined the extent to which changes over time in clinicians' responses to measures of work attitude (eg, job satisfaction) and psychological climate (eg, supervisor support) could predict actual turnover and turnover intentions above and beyond absolute levels of these respective measures. Longitudinal data for this study were collected from a sample of clinicians (N = 96) being trained to implement an evidence-based treatment for adolescent substance use disorders. Supporting findings from a recent staff turnover study, we found job satisfaction change was able to predict actual turnover above and beyond average levels of job satisfaction. Representing new contributions to the staff turnover literature, we also found that change over time in several other key measures (eg, job satisfaction, role manageability, role clarity) explained a significant amount of variance in turnover intentions above and beyond the absolute level of each respective measure. A key implication of the current study is that organizations seeking to improve their ability to assess risk for staff turnover may want to consider assessing staff at multiple points in time in order to identify systematic changes in key employee attitudes like turnover intentions and job satisfaction.

Predictors of Staff Turnover and Turnover Intentions within Addiction Treatment Settings: Change Over Time Matters

PubMed Central

Garner, Bryan R; Hunter, Brooke D

2014-01-01

This study examined the extent to which changes over time in clinicians’ responses to measures of work attitude (eg, job satisfaction) and psychological climate (eg, supervisor support) could predict actual turnover and turnover intentions above and beyond absolute levels of these respective measures. Longitudinal data for this study were collected from a sample of clinicians (N = 96) being trained to implement an evidence-based treatment for adolescent substance use disorders. Supporting findings from a recent staff turnover study, we found job satisfaction change was able to predict actual turnover above and beyond average levels of job satisfaction. Representing new contributions to the staff turnover literature, we also found that change over time in several other key measures (eg, job satisfaction, role manageability, role clarity) explained a significant amount of variance in turnover intentions above and beyond the absolute level of each respective measure. A key implication of the current study is that organizations seeking to improve their ability to assess risk for staff turnover may want to consider assessing staff at multiple points in time in order to identify systematic changes in key employee attitudes like turnover intentions and job satisfaction. PMID:25336960

Transformation of soil organics under extreme climate events: a project description

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia

2017-04-01

Recent climate scenarios predict not only continued global warming but also an increased frequency and intensity of extreme climatic events such as strong changes in temperature and precipitation with unusual regional dynamics. Weather anomalies at European territory of Russia are currently revealed as long-term drought and strong showers in summer and as an increased frequency of soil freezing-thawing cycles. Climate extremes totally change biogeochemical processes and elements cycling both at the ecosystem level and at the level of soil profile mainly affecting soil biota. Misbalance in these processes can cause a reduction of soil carbon stock and an increase of greenhouse gases emission. Our project aims to reveal the transformation mechanisms of soil organic matter caused by extreme weather events taking into consideration the role of biotic-abiotic interactions in regulation of formation, maintenance and turnover of soil carbon stock. Our research strategy is based on the novel concept considering extreme climatic events (showers after long-term droughts, soil flooding, freezing-thawing) as abiotic factors initiating a microbial succession. Study on stoichiometric flexibility of plants under climate extremes as well as on resulting response of soil heterotrophs on stoichiometric changes in substrate will be used for experimental prove and further development of the theory of ecological stoichiometry. The results enable us to reveal the mechanisms of biotic - abiotic interactions responsible for the balance between mobilization and stabilization of soil organic matter. Identified mechanisms will form the basis of an ecosystem model enabled to predict the effects of extreme climatic events on biogenic carbon cycle in the biosphere.

Critical Role of Transient Activity of MT1-MMP for ECM Degradation in Invadopodia

PubMed Central

Watanabe, Ayako; Hosino, Daisuke; Koshikawa, Naohiko; Seiki, Motoharu; Suzuki, Takashi; Ichikawa, Kazuhisa

2013-01-01

Focal degradation of extracellular matrix (ECM) is the first step in the invasion of cancer cells. MT1-MMP is a potent membrane proteinase employed by aggressive cancer cells. In our previous study, we reported that MT1-MMP was preferentially located at membrane protrusions called invadopodia, where MT1-MMP underwent quick turnover. Our computer simulation and experiments showed that this quick turnover was essential for the degradation of ECM at invadopodia (Hoshino, D., et al., (2012) PLoS Comp. Biol., 8: e1002479). Here we report on characterization and analysis of the ECM-degrading activity of MT1-MMP, aiming at elucidating a possible reason for its repetitive insertion in the ECM degradation. First, in our computational model, we found a very narrow transient peak in the activity of MT1-MMP followed by steady state activity. This transient activity was due to the inhibition by TIMP-2, and the steady state activity of MT1-MMP decreased dramatically at higher TIMP-2 concentrations. Second, we evaluated the role of the narrow transient activity in the ECM degradation. When the transient activity was forcibly suppressed in computer simulations, the ECM degradation was heavily suppressed, indicating the essential role of this transient peak in the ECM degradation. Third, we compared continuous and pulsatile turnover of MT1-MMP in the ECM degradation at invadopodia. The pulsatile insertion showed basically consistent results with the continuous insertion in the ECM degradation, and the ECM degrading efficacy depended heavily on the transient activity of MT1-MMP in both models. Unexpectedly, however, low-frequency/high-concentration insertion of MT1-MMP was more effective in ECM degradation than high-frequency/low-concentration pulsatile insertion even if the time-averaged amount of inserted MT1-MMP was the same. The present analysis and characterization of ECM degradation by MT1-MMP together with our previous report indicate a dynamic nature of MT1-MMP at invadopodia and the importance of its transient peak in the degradation of the ECM. PMID:23737743

RNA Sequencing Identifies New RNase III Cleavage Sites in Escherichia coli and Reveals Increased Regulation of mRNA

DOE PAGES

Gordon, Gina C.; Cameron, Jeffrey C.; Pfleger, Brian F.

2017-03-28

Ribonucleases facilitate rapid turnover of RNA, providing cells with another mechanism to adjust transcript and protein levels in response to environmental conditions. While many examples have been documented, a comprehensive list of RNase targets is not available. To address this knowledge gap, we compared levels of RNA sequencing coverage of Escherichia coli and a corresponding RNase III mutant to expand the list of known RNase III targets. RNase III is a widespread endoribonuclease that binds and cleaves double-stranded RNA in many critical transcripts. RNase III cleavage at novel sites found in aceEF, proP, tnaC, dctA, pheM, sdhC, yhhQ, glpT, aceK,more » and gluQ accelerated RNA decay, consistent with previously described targets wherein RNase III cleavage initiates rapid degradation of secondary messages by other RNases. In contrast, cleavage at three novel sites in the ahpF, pflB, and yajQ transcripts led to stabilized secondary transcripts. Two other novel sites in hisL and pheM overlapped with transcriptional attenuators that likely serve to ensure turnover of these highly structured RNAs. Many of the new RNase III target sites are located on transcripts encoding metabolic enzymes. For instance, two novel RNase III sites are located within transcripts encoding enzymes near a key metabolic node connecting glycolysis and the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase activity was increased in an rnc deletion mutant compared to the wild-type (WT) strain in early stationary phase, confirming the novel link between RNA turnover and regulation of pathway activity. Identification of these novel sites suggests that mRNA turnover may be an underappreciated mode of regulating metabolism. IMPORTANCE: The concerted action and overlapping functions of endoribonucleases, exoribonucleases, and RNA processing enzymes complicate the study of global RNA turnover and recycling of specific transcripts. More information about RNase specificity and activity is needed to make predictions of transcript half-life and to design synthetic transcripts with optimal stability. RNase III does not have a conserved target sequence but instead recognizes RNA secondary structure. Prior to this study, only a few RNase III target sites in E. coli were known, so we used RNA sequencing to provide a more comprehensive list of cleavage sites and to examine the impact of RNase III on transcript degradation. Finally, with this added information on how RNase III participates in transcript regulation and recycling, a more complete picture of RNA turnover can be developed for E. coli. Similar approaches could be used to augment our understanding of RNA turnover in other bacteria.« less

RNA Sequencing Identifies New RNase III Cleavage Sites in Escherichia coli and Reveals Increased Regulation of mRNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, Gina C.; Cameron, Jeffrey C.; Pfleger, Brian F.

Ribonucleases facilitate rapid turnover of RNA, providing cells with another mechanism to adjust transcript and protein levels in response to environmental conditions. While many examples have been documented, a comprehensive list of RNase targets is not available. To address this knowledge gap, we compared levels of RNA sequencing coverage of Escherichia coli and a corresponding RNase III mutant to expand the list of known RNase III targets. RNase III is a widespread endoribonuclease that binds and cleaves double-stranded RNA in many critical transcripts. RNase III cleavage at novel sites found in aceEF, proP, tnaC, dctA, pheM, sdhC, yhhQ, glpT, aceK,more » and gluQ accelerated RNA decay, consistent with previously described targets wherein RNase III cleavage initiates rapid degradation of secondary messages by other RNases. In contrast, cleavage at three novel sites in the ahpF, pflB, and yajQ transcripts led to stabilized secondary transcripts. Two other novel sites in hisL and pheM overlapped with transcriptional attenuators that likely serve to ensure turnover of these highly structured RNAs. Many of the new RNase III target sites are located on transcripts encoding metabolic enzymes. For instance, two novel RNase III sites are located within transcripts encoding enzymes near a key metabolic node connecting glycolysis and the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase activity was increased in an rnc deletion mutant compared to the wild-type (WT) strain in early stationary phase, confirming the novel link between RNA turnover and regulation of pathway activity. Identification of these novel sites suggests that mRNA turnover may be an underappreciated mode of regulating metabolism. IMPORTANCE: The concerted action and overlapping functions of endoribonucleases, exoribonucleases, and RNA processing enzymes complicate the study of global RNA turnover and recycling of specific transcripts. More information about RNase specificity and activity is needed to make predictions of transcript half-life and to design synthetic transcripts with optimal stability. RNase III does not have a conserved target sequence but instead recognizes RNA secondary structure. Prior to this study, only a few RNase III target sites in E. coli were known, so we used RNA sequencing to provide a more comprehensive list of cleavage sites and to examine the impact of RNase III on transcript degradation. Finally, with this added information on how RNase III participates in transcript regulation and recycling, a more complete picture of RNA turnover can be developed for E. coli. Similar approaches could be used to augment our understanding of RNA turnover in other bacteria.« less

The costs of nurse turnover, part 2: application of the Nursing Turnover Cost Calculation Methodology.

PubMed

Jones, Cheryl Bland

2005-01-01

This is the second article in a 2-part series focusing on nurse turnover and its costs. Part 1 (December 2004) described nurse turnover costs within the context of human capital theory, and using human resource accounting methods, presented the updated Nursing Turnover Cost Calculation Methodology. Part 2 presents an application of this method in an acute care setting and the estimated costs of nurse turnover that were derived. Administrators and researchers can use these methods and cost information to build a business case for nurse retention.

Store turnover as a predictor of food and beverage provider turnover and associated dietary intake estimates in very remote Indigenous communities.

PubMed

Wycherley, Thomas; Ferguson, Megan; O'Dea, Kerin; McMahon, Emma; Liberato, Selma; Brimblecombe, Julie

2016-12-01

Determine how very-remote Indigenous community (RIC) food and beverage (F&B) turnover quantities and associated dietary intake estimates derived from only stores, compare with values derived from all community F&B providers. F&B turnover quantity and associated dietary intake estimates (energy, micro/macronutrients and major contributing food types) were derived from 12-months transaction data of all F&B providers in three RICs (NT, Australia). F&B turnover quantities and dietary intake estimates from only stores (plus only the primary store in multiple-store communities) were expressed as a proportion of complete F&B provider turnover values. Food types and macronutrient distribution (%E) estimates were quantitatively compared. Combined stores F&B turnover accounted for the majority of F&B quantity (98.1%) and absolute dietary intake estimates (energy [97.8%], macronutrients [≥96.7%] and micronutrients [≥83.8%]). Macronutrient distribution estimates from combined stores and only the primary store closely aligned complete provider estimates (≤0.9% absolute). Food types were similar using combined stores, primary store or complete provider turnover. Evaluating combined stores F&B turnover represents an efficient method to estimate total F&B turnover quantity and associated dietary intake in RICs. In multiple-store communities, evaluating only primary store F&B turnover provides an efficient estimate of macronutrient distribution and major food types. © 2016 Public Health Association of Australia.

An Integrative Literature Review of Patient Turnover in Inpatient Hospital Settings.

PubMed

Park, Shin Hye; Weaver, Lindsay; Mejia-Johnson, Lydia; Vukas, Rachel; Zimmerman, Julie

2016-05-01

High patient turnover can result in fragmentation of nursing care. It can also increase nursing workload and thus impede the ability of nurses to provide safe and high-quality care. We reviewed 20 studies that examined patient turnover in relation to nursing workload, staffing, and patient outcomes as well as interventions in inpatient hospital settings. The studies consistently addressed the importance of accounting for patient turnover when estimating nurse staffing needs. They also showed that patient turnover varied by time, day, and unit type. Researchers found that higher patient turnover was associated with adverse events; however, further research on this topic is needed because evidence on the effect of patient turnover on patient outcomes is not yet strong and conclusive. We suggest that researchers and administrators need to pay more attention to patterns and levels of patient turnover and implement managerial strategies to reduce nursing workload and improve patient outcomes. © The Author(s) 2015.

Supervisory Turnover in Outpatient Substance Abuse Treatment

PubMed Central

Knight, Danica K.; Broome, Kirk M.; Edwards, Jennifer R.; Flynn, Patrick M.

2009-01-01

Staff turnover is a significant issue within substance abuse treatment, with implications for service delivery and organizational health. This study examined factors associated with turnover among supervisors in outpatient substance abuse treatment. Turnover was conceptualized as being an individual response to organizational-level influences, and predictors represent aggregate program measures. Participants included 532 staff (including 467 counselors and 65 clinical/program directors) from 90 programs in four regions of the USA. Using logistic regression, analyses of structural factors indicated that programs affiliated with a parent organization and those providing more counseling hours to clients had higher turnover rates. When measures of job attitudes were included, only parent affiliation and collective appraisal of satisfaction were related to turnover. Subsequent analyses identified a trend toward increased supervisory turnover when satisfaction was low following the departure of a previous supervisor. These findings suggest that organizational-level factors can be influential in supervisory turnover. PMID:19949883

Causes and consequences of collective turnover: a meta-analytic review.

PubMed

Heavey, Angela L; Holwerda, Jacob A; Hausknecht, John P

2013-05-01

Given growing interest in collective turnover (i.e., employee turnover at unit and organizational levels), the authors propose an organizing framework for its antecedents and consequences and test it using meta-analysis. Based on analysis of 694 effect sizes drawn from 82 studies, results generally support expected relationships across the 6 categories of collective turnover antecedents, with somewhat stronger and more consistent results for 2 categories: human resource management inducements/investments and job embeddedness signals. Turnover was negatively related to numerous performance outcomes, more strongly so for proximal rather than distal outcomes. Several theoretically grounded moderators help to explain average effect-size heterogeneity for both antecedents and consequences of turnover. Relationships generally did not vary according to turnover type (e.g., total or voluntary), although the relative absence of collective-level involuntary turnover studies is noted and remains an important avenue for future research. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Examining the temporal relationship between psychological climate, work attitude, and staff turnover

PubMed Central

Garner, Bryan R.; Hunter, Brooke D.

2012-01-01

Relative to the broader industrial-organizational (I-O) psychology field, research on the turnover of substance use disorder (SUD) treatment staff is in its infancy. Despite its long and rich history, recent reviews of the turnover literature within I-O psychology have noted there remains considerable room for improvement. In particular, recommendations have been made for research that considers time in the turnover process and explores more distal causes of staff turnover. Addressing these gaps, this paper examined the temporal relationship between latent measures of psychological climate, work attitude, and staff turnover. Using data from 95 SUD treatment staff clustered within 29 treatment organizations, multilevel discrete-time survival analyses revealed that a latent measure of work attitude (e.g., job satisfaction, pay satisfaction, turnover intentions) fully mediated the temporal relationship between latent measures of psychological climate (e.g., supervisor support, coworker support, role conflict) and subsequent staff turnover. PMID:22658290

Forest turnover rates follow global and regional patterns of productivity

USGS Publications Warehouse

Stephenson, N.L.; van Mantgem, P.J.

2005-01-01

Using a global database, we found that forest turnover rates (the average of tree mortality and recruitment rates) parallel broad-scale patterns of net primary productivity. First, forest turnover was higher in tropical than in temperate forests. Second, as recently demonstrated by others, Amazonian forest turnover was higher on fertile than infertile soils. Third, within temperate latitudes, turnover was highest in angiosperm forests, intermediate in mixed forests, and lowest in gymnosperm forests. Finally, within a single forest physiognomic type, turnover declined sharply with elevation (hence with temperature). These patterns of turnover in populations of trees are broadly similar to the patterns of turnover in populations of plant organs (leaves and roots) found in other studies. Our findings suggest a link between forest mass balance and the population dynamics of trees, and have implications for understanding and predicting the effects of environmental changes on forest structure and terrestrial carbon dynamics. ??2005 Blackwell Publishing Ltd/CNRS.

Spatial variation in the climatic predictors of species compositional turnover and endemism.

PubMed

Di Virgilio, Giovanni; Laffan, Shawn W; Ebach, Malte C; Chapple, David G

2014-08-01

Previous research focusing on broad-scale or geographically invariant species-environment dependencies suggest that temperature-related variables explain more of the variation in reptile distributions than precipitation. However, species-environment relationships may exhibit considerable spatial variation contingent upon the geographic nuances that vary between locations. Broad-scale, geographically invariant analyses may mask this local variation and their findings may not generalize to different locations at local scales. We assess how reptile-climatic relationships change with varying spatial scale, location, and direction. Since the spatial distributions of diversity and endemism hotspots differ for other species groups, we also assess whether reptile species turnover and endemism hotspots are influenced differently by climatic predictors. Using New Zealand reptiles as an example, the variation in species turnover, endemism and turnover in climatic variables was measured using directional moving window analyses, rotated through 360°. Correlations between the species turnover, endemism and climatic turnover results generated by each rotation of the moving window were analysed using multivariate generalized linear models applied at national, regional, and local scales. At national-scale, temperature turnover consistently exhibited the greatest influence on species turnover and endemism, but model predictive capacity was low (typically r (2) = 0.05, P < 0.001). At regional scales the relative influence of temperature and precipitation turnover varied between regions, although model predictive capacity was also generally low. Climatic turnover was considerably more predictive of species turnover and endemism at local scales (e.g., r (2) = 0.65, P < 0.001). While temperature turnover had the greatest effect in one locale (the northern North Island), there was substantial variation in the relative influence of temperature and precipitation predictors in the remaining four locales. Species turnover and endemism hotspots often occurred in different locations. Climatic predictors had a smaller influence on endemism. Our results caution against assuming that variability in temperature will always be most predictive of reptile biodiversity across different spatial scales, locations and directions. The influence of climatic turnover on the species turnover and endemism of other taxa may exhibit similar patterns of spatial variation. Such intricate variation might be discerned more readily if studies at broad scales are complemented by geographically variant, local-scale analyses.

Involvement of Abscisic Acid in PSII Photodamage and D1 Protein Turnover for Light-Induced Premature Senescence of Rice Flag Leaves

PubMed Central

Wang, Fubiao; Liu, Jianchao; Chen, Minxue; Zhou, Lujian; Li, Zhaowei; Zhao, Qian; Pan, Gang; Zaidi, Syed-Hassan-Raza; Cheng, Fangmin

2016-01-01

D1 protein in the PSII reaction center is the major target of photodamage, and it exhibits the highest turnover rate among all the thylakoid proteins. In this paper, rice psf (premature senescence of flag leaves) mutant and its wild type were used to investigate the genotype-dependent alteration in PSII photo-damage and D1 protein turnover during leaf senescence and its relation to ABA accumulation in senescent leaves. The symptom and extent of leaf senescence of the psf mutant appeared to be sunlight-dependent under natural field condition. The psf also displayed significantly higher levels of ABA accumulation in senescent leaves than the wild type. However, the premature senescence lesion of psf leaves could be alleviated by shaded treatment, concomitantly with the strikingly suppressed ABA level in the shaded areas of flag leaves. The change in ABA concentration contributed to the regulation of shade-delayed leaf senescence. The participation of ABA in the timing of senescence initiation and in the subsequent rate of leaf senescence was closely associated with PSII photodamage and D1 protein turnover during leaf senescence, in which the transcriptional expression of several key genes (psbA, psbB, psbC and OsFtsH2) involved in D1 protein biosynthesis and PSII repair cycle was seriously suppressed by the significantly increased ABA level. This response resulted in the low rate of D1 protein synthesis and impaired repair recovery in the presence of ABA. The psf showed evidently decreased D1 protein amount in the senescent leaves. Both the inhibition of de novo synthesized D1 protein and the slow rate of proteolytic removal for the photodamaged D1 protein was among the most crucial steps for the linkage between light-dependent leaf senescence and the varying ABA concentration in psf mutant leaves. OsFtsH2 transcriptional expression possibly played an important role in the regulation of D1 protein turnover and PSII repair cycle in relation to ABA mediated leaf senescence. PMID:27532299

A comparative review of nurse turnover rates and costs across countries.

PubMed

Duffield, Christine M; Roche, Michael A; Homer, Caroline; Buchan, James; Dimitrelis, Sofia

2014-12-01

To compare nurse turnover rates and costs from four studies in four countries (US, Canada, Australia, New Zealand) that have used the same costing methodology; the original Nursing Turnover Cost Calculation Methodology. Measuring and comparing the costs and rates of turnover is difficult because of differences in definitions and methodologies. Comparative review. Searches were carried out within CINAHL, Business Source Complete and Medline for studies that used the original Nursing Turnover Cost Calculation Methodology and reported on both costs and rates of nurse turnover, published from 2014 and prior. A comparative review of turnover data was conducted using four studies that employed the original Nursing Turnover Cost Calculation Methodology. Costing data items were converted to percentages, while total turnover costs were converted to US 2014 dollars and adjusted according to inflation rates, to permit cross-country comparisons. Despite using the same methodology, Australia reported significantly higher turnover costs ($48,790) due to higher termination (~50% of indirect costs) and temporary replacement costs (~90% of direct costs). Costs were almost 50% lower in the US ($20,561), Canada ($26,652) and New Zealand ($23,711). Turnover rates also varied significantly across countries with the highest rate reported in New Zealand (44·3%) followed by the US (26·8%), Canada (19·9%) and Australia (15·1%). A significant proportion of turnover costs are attributed to temporary replacement, highlighting the importance of nurse retention. The authors suggest a minimum dataset is also required to eliminate potential variability across countries, states, hospitals and departments. © 2014 John Wiley & Sons Ltd.

Effects of a preceptorship programme on turnover rate, cost, quality and professional development.

PubMed

Lee, Tso-Ying; Tzeng, Wen-Chii; Lin, Chia-Huei; Yeh, Mei-Ling

2009-04-01

The purpose of the present study was to design a preceptorship programme and to evaluate its effects on turnover rate, turnover cost, quality of care and professional development. A high turnover rate of nurses is a common global problem. How to improve nurses' willingness to stay in their jobs and reduce the high turnover rate has become a focus. Well-designed preceptorship programmes could possibly decrease turnover rates and improve professional development. A quasi-experimental research design was used. First, a preceptorship programme was designed to establish the role and responsibilities of preceptors in instructing new nurses. Second, a quasi-experimental design was used to evaluate the preceptorship programme. Data on new nurses' turnover rate, turnover cost, quality of nursing care, satisfaction of preceptor's teaching and preceptor's perception were measured. After conducting the preceptorship programme, the turnover rate was 46.5% less than the previous year. The turnover cost was decreased by US$186,102. Additionally, medication error rates made by new nurses dropped from 50-0% and incident rates of adverse events and falls decreased. All new nurses were satisfied with preceptor guidance. The preceptorship programme effectively lowered the turnover rate of new nurses, reduced turnover costs and enhanced the quality of nursing care, especially by reducing medication error incidents. Positive feedback about the programme was received from new nurses. Study findings may offer healthcare administrators another option for retaining new nurses, controlling costs, improving quality and fostering professional development. In addition, incentives and effective support from the organisation must be considered when preceptors perform preceptorship responsibilities.

The effect of smoke-free policies on revenue in bars in Tasmania, Australia.

PubMed

Lal, A; Siahpush, M

2009-10-01

To examine the impact of smoke-free policies on revenue in Tasmanian bars. Monthly sales turnover from January 2002 to March 2007, provided by the Australian Bureau of Statistics was analysed. There were two (1) the ratio of monthly bar sales turnover in Tasmania to monthly bar sales turnover in four other Australian states, and (2) the ratio of monthly bar turnover to monthly retail turnover in Tasmania. Linear regression was used to assess the impact of the smoke-free policy on expenditure. The smoke-free policy had no effect on sales turnover. The smoke-free policy protects hospitality workers and patrons from exposure to secondhand smoke and has had no adverse effect on sales turnover.

Nitrates and bone turnover (NABT) - trial to select the best nitrate preparation: study protocol for a randomized controlled trial.

PubMed

Bucur, Roxana C; Reid, Lauren S; Hamilton, Celeste J; Cummings, Steven R; Jamal, Sophie A

2013-09-08

Organic nitrates uncouple bone turnover, improve bone mineral density, and improve trabecular and cortical components of bone. These changes in turnover, strength and geometry may translate into an important reduction in fractures. However, before proceeding with a large fracture trial, there is a need to identify the nitrate formulation that has both the greatest efficacy (with regards to bone turnover markers) and gives the fewest headaches. Ascertaining which nitrate formulation this may be is the purpose of the current study. This will be an open-label randomized, controlled trial conducted at Women's College Hospital comparing five formulations of nitrates for their effects on bone turnover markers and headache. We will recruit postmenopausal women age 50 years or older with no contraindications to nitroglycerin. Our trial will consist of a run-in phase and a treatment phase. We will enroll 420 women in the run-in phase, each to receive all of the 5 potential treatments in random order for 2 days, each with a 2-day washout period between treatments. Those who tolerate all formulations will enter the 12-week treatment phase and be randomly assigned to one of five groups: 0.3 mg sublingual nitroglycerin tablet, 0.6 mg of the sublingual tablet, a 20 mg tablet of isosorbide mononitrate, a 160 mg nitroglycerin transdermal patch (used for 8 h), and 15 mg of nitroglycerin ointment as used in a previous trial by our group. We will continue enrolment until we have randomized 210 women or 35 women per group. Concentrations of bone formation (bone-specific alkaline phosphatase and procollagen type I N-terminal propeptide) and bone resorption (C-telopeptides of collagen crosslinks and N-terminal crosslinks of collagen) agents will be measured in samples taken at study entry (the start of the run in phase) and 12 weeks. Subjects will record the frequency and severity of headaches daily during the run-in phase and then monthly after that. We will use the 'multiple comparisons with the best' approach for data analyses, as this strategy allows practical considerations of ease of use and tolerability to guide selection of the preparation for future studies. Data from this protocol will be used to develop a randomized, controlled trial of nitrates to prevent osteoporotic fractures. ClinicalTrials.gov Identifier: NCT01387672. Controlled-Trials.com: ISRCTN08860742.

How Does Supervisor Support Influence Turnover Intent Among Frontline Hospital Workers? The Mediating Role of Affective Commitment.

PubMed

Nichols, Helen M; Swanberg, Jennifer E; Bright, Charlotte Lyn

2016-01-01

Turnover among frontline hospital service workers can disrupt organizational effectiveness, reduce profitability, and limit the ability to provide high-quality, patient-centered care. This concern is compounded by the increasing reliance on frontline supervisors to manage this workforce, often without necessary training and support. However, research addressing the relationship between frontline supervisor support and intent to turnover among service workers and the process by which these variables are related is limited. By surveying 270 housekeeping and dietary service workers employed at 2 US hospitals, this study examined the relationship between supervisor support and turnover intent and assessed the mediating role of affective commitment between supervisor support and intent to turnover. Turnover intentions were lower for workers who reported greater levels of supervisor support and affective commitment; both supervisor support and affective commitment were significant predictors of turnover intent when tested individually. However, when controlling for affective commitment, supervisor support no longer predicted turnover intent, indicating that affective commitment fully mediated the relationship between supervisor support and intent to turnover. Implications for further research and organizational practice are discussed.

Complexity Science and the Dynamics of Climate and Communication: Reducing Nursing Home Turnover

PubMed Central

Anderson, Ruth A.; Corazzini, Kirsten N.; McDaniel, Reuben R.

2008-01-01

Purpose Turnover in nursing homes is a widespread problem adversely affecting care quality. Using complexity theory, we tested the effect of administrative climate, communication patterns, and the interaction between the two on turnover, controlling for facility context. Design and Methods Perceptions of administrative climate and communication were collected from 3,449 employees in 164 randomly sampled nursing homes, and they were linked to secondary data on facility characteristics, resource allocation, and turnover. We used hierarchical regression to test the hypotheses. Results Climate and communication both affected turnover, but lower turnover was dependent on the interaction between climate and communication. In nursing homes with reward-based administrative climates, higher levels of communication openness and accuracy explained lower turnover of licensed vocational nurses and certified nurse assistants, relative to nursing homes with an ambiguous climate. Adequate staffing and longer tenure of the nursing director were also important predictors of turnover. Implications Although context is important, managers can also influence turnover by addressing climate and communication patterns and by encouraging stable nursing leadership. PMID:15197292

Enhancer regions show high histone H3.3 turnover that changes during differentiation

PubMed Central

Deaton, Aimee M; Gómez-Rodríguez, Mariluz; Mieczkowski, Jakub; Tolstorukov, Michael Y; Kundu, Sharmistha; Sadreyev, Ruslan I; Jansen, Lars ET; Kingston, Robert E

2016-01-01

The organization of DNA into chromatin is dynamic; nucleosomes are frequently displaced to facilitate the ability of regulatory proteins to access specific DNA elements. To gain insight into nucleosome dynamics, and to follow how dynamics change during differentiation, we used a technique called time-ChIP to quantitatively assess histone H3.3 turnover genome-wide during differentiation of mouse ESCs. We found that, without prior assumptions, high turnover could be used to identify regions involved in gene regulation. High turnover was seen at enhancers, as observed previously, with particularly high turnover at super-enhancers. In contrast, regions associated with the repressive Polycomb-Group showed low turnover in ESCs. Turnover correlated with DNA accessibility. Upon differentiation, numerous changes in H3.3 turnover rates were observed, the majority of which occurred at enhancers. Thus, time-ChIP measurement of histone turnover shows that active enhancers are unusually dynamic in ESCs and changes in highly dynamic nucleosomes predominate at enhancers during differentiation. DOI: http://dx.doi.org/10.7554/eLife.15316.001 PMID:27304074

Nickel-centred proton reduction catalysis in a model of [NiFe] hydrogenase

NASA Astrophysics Data System (ADS)

Brazzolotto, Deborah; Gennari, Marcello; Queyriaux, Nicolas; Simmons, Trevor R.; Pécaut, Jacques; Demeshko, Serhiy; Meyer, Franc; Orio, Maylis; Artero, Vincent; Duboc, Carole

2016-11-01

Hydrogen production through water splitting is one of the most promising solutions for the storage of renewable energy. [NiFe] hydrogenases are organometallic enzymes containing nickel and iron centres that catalyse hydrogen evolution with performances that rival those of platinum. These enzymes provide inspiration for the design of new molecular catalysts that do not require precious metals. However, all heterodinuclear NiFe models reported so far do not reproduce the Ni-centred reactivity found at the active site of [NiFe] hydrogenases. Here, we report a structural and functional NiFe mimic that displays reactivity at the Ni site. This is shown by the detection of two catalytic intermediates that reproduce structural and electronic features of the Ni-L and Ni-R states of the enzyme during catalytic turnover. Under electrocatalytic conditions, this mimic displays high rates for H2 evolution (second-order rate constant of 2.5 × 104 M-1 s-1 turnover frequency of 250 s-1 at 10 mM H+ concentration) from mildly acidic solutions.

Ambient nitrogen reduction cycle using a hybrid inorganic–biological system

PubMed Central

Liu, Chong; Sakimoto, Kelsey K.; Colón, Brendan C.; Silver, Pamela A.

2017-01-01

We demonstrate the synthesis of NH3 from N2 and H2O at ambient conditions in a single reactor by coupling hydrogen generation from catalytic water splitting to a H2-oxidizing bacterium Xanthobacter autotrophicus, which performs N2 and CO2 reduction to solid biomass. Living cells of X. autotrophicus may be directly applied as a biofertilizer to improve growth of radishes, a model crop plant, by up to ∼1,440% in terms of storage root mass. The NH3 generated from nitrogenase (N2ase) in X. autotrophicus can be diverted from biomass formation to an extracellular ammonia production with the addition of a glutamate synthetase inhibitor. The N2 reduction reaction proceeds at a low driving force with a turnover number of 9 × 109 cell–1 and turnover frequency of 1.9 × 104 s–1⋅cell–1 without the use of sacrificial chemical reagents or carbon feedstocks other than CO2. This approach can be powered by renewable electricity, enabling the sustainable and selective production of ammonia and biofertilizers in a distributed manner. PMID:28588143

Photochemical Water Oxidation Using {PMo12O40@Mo72Fe30}n Based Soft Oxometalate

NASA Astrophysics Data System (ADS)

Das, Santu; Roy, Soumyajit

Finding an alternative energy resource which can produce clean energy at a low cost is one of the major concerns of our times. The conversion of light energy into chemical energy is one key step forward in the direction. With that end in view photochemical water oxidation to produce oxygen plays a crucial role. In the present paper we have synthesized a soft oxometalate {PMo12O40@Mo72Fe30}n(1) from its well-known precursor polyoxometalate constituent [Muller et al., Chem. Commun. 1, 657 (2001)]. It is known that in the matter of catalysis, high surface area, possibility of heterogenization, recoverability makes soft oxometalates (SOMs) attractive as catalytic materials. Here we exploit such advantages of SOMs. The SOM based material acts as an active catalyst for photochemical water oxidation reaction with a maximum turnover number of 20256 and turnover frequency of 24.11min-1. The catalyst material is stable under photochemical reaction conditions and therefore can be reused for multiple photo catalytic water oxidation reaction cycles.

A Bimetallic Nickel-Gallium Complex Catalyzes CO2 Hydrogenation via the Intermediacy of an Anionic d10 Nickel Hydride.

PubMed

Cammarota, Ryan C; Vollmer, Matthew V; Xie, Jing; Ye, Jingyun; Linehan, John C; Burgess, Samantha A; Appel, Aaron M; Gagliardi, Laura; Lu, Connie C

2017-10-11

Large-scale CO 2 hydrogenation could offer a renewable stream of industrially important C 1 chemicals while reducing CO 2 emissions. Critical to this opportunity is the requirement for inexpensive catalysts based on earth-abundant metals instead of precious metals. We report a nickel-gallium complex featuring a Ni(0)→Ga(III) bond that shows remarkable catalytic activity for hydrogenating CO 2 to formate at ambient temperature (3150 turnovers, turnover frequency = 9700 h -1 ), compared with prior homogeneous Ni-centered catalysts. The Lewis acidic Ga(III) ion plays a pivotal role in stabilizing catalytic intermediates, including a rare anionic d 10 Ni hydride. Structural and in situ characterization of this reactive intermediate support a terminal Ni-H moiety, for which the thermodynamic hydride donor strength rivals those of precious metal hydrides. Collectively, our experimental and computational results demonstrate that modulating a transition metal center via a direct interaction with a Lewis acidic support can be a powerful strategy for promoting new reactivity paradigms in base-metal catalysis.

Synthesis, characterization, and catalytic activity in Suzuki coupling and catalase-like reactions of new chitosan supported Pd catalyst.

PubMed

Baran, Talat; Inanan, Tülden; Menteş, Ayfer

2016-07-10

The aim of this study is to analyze the synthesis of a new chitosan supported Pd catalyst and examination of its catalytic activity in: Pd catalyst was synthesized using chitosan as a biomaterial and characterized with FTIR, TG/DTG, XRD, (1)H NMR, (13)C NMR, SEM-EDAX, ICP-OES, Uv-vis spectroscopies, and magnetic moment, along with molar conductivity analysis. Biomaterial supported Pd catalyst indicated high activity and long life time as well as excellent turnover number (TON) and turnover frequency (TOF) values in Suzuki reaction. Biomaterial supported Pd catalyst catalyzed H2O2 decomposition reaction with considerable high activity using comparatively small loading catalyst (10mg). Redox potential of biomaterial supported Pd catalyst was still high without negligible loss (13% decrease) after 10 cycles in reusability tests. As a consequence, eco-friendly biomaterial supported Pd catalyst has superior properties such as high thermal stability, long life time, easy removal from reaction mixture and durability to air, moisture and high temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Graphite-Conjugated Rhenium Catalysts for Carbon Dioxide Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oh, Seokjoon; Gallagher, James R.; Miller, Jeffrey T.

2016-02-17

Condensation of fac-Re(5,6-diamino-1,10-phenanthroline)(CO)(3)Cl to o-quinone edge defects on graphitic carbon surfaces generates graphite-conjugated rhenium (GCC-Re) catalysts that are highly active for CO2 reduction to CO in acetonitrile electrolyte. X-ray photo-electron and X-ray absorption spectroscopies establish the formation of surface-bound Re centers with well-defined coordination environments. GCC-Re species on glassy carbon surfaces display catalytic currents greater than 50 mA cm(-2) with 96 +/- 3% Faradaic efficiency for CO production. Normalized for the number of Re active sites, GCC-Re catalysts exhibit higher turnover frequencies than that of a soluble molecular analogue, fac-Re(1,10-phenanthroline)(CO)(3)Cl, and turnover numbers greater than 12,000. In contrast to themore » molecular analogue, GCC-Re surfaces display a Tafel slope of 150 mV/decade, indicative of a catalytic mechanism involving rate-limiting one-electron transfer. This work establishes graphite conjugation as a powerful strategy for generating well-defined, tunable, heterogeneous electrocatalysts on ubiquitous graphitic carbon surfaces.« less

Nurse Knowledge, Work Environment, and Turnover in Highly Specialized Pediatric End-of-Life Care.

PubMed

Lindley, Lisa C; Cozad, Melanie J

2017-07-01

To examine the relationship between nurse knowledge, work environment, and registered nurse (RN) turnover in perinatal hospice and palliative care organizations. Using nurse intellectual capital theory, a multivariate analysis was conducted with 2007 National Home and Hospice Care Survey data. Perinatal hospice and palliative care organizations experienced a 5% turnover rate. The professional experience of advanced practice nurses (APNs) was significantly related to turnover among RNs (β = -.032, P < .05). Compared to organizations with no APNs professional experience, clinical nurse specialists and nurse practitioners significantly reduced RN turnover by 3 percentage points. No other nurse knowledge or work environment variables were associated with RN turnover. Several of the control variables were also associated with RN turnover in the study; Organizations serving micropolitan (β = -.041, P < .05) and rural areas (β = -.037, P < .05) had lower RN turnover compared to urban areas. Organizations with a technology climate where nurses used electronic medical records had a higher turnover rate than those without (β = .036, P < .05). The findings revealed that advanced professional experience in the form of APNs was associated with reductions in RN turnover. This suggests that having a clinical nurse specialist or nurse practitioner on staff may provide knowledge and experience to other RNs, creating stability within the organization.

Mitochondrial proteostasis as a shared characteristic of slowed aging: the importance of considering cell proliferation.

PubMed

Hamilton, Karyn L; Miller, Benjamin F

2017-10-15

Proteostasis is one of the seven "pillars of aging research" identified by the Trans-NIH Geroscience Initiative and loss of proteostasis is associated with aging and age-related chronic disease. Accumulated protein damage and resultant cellular dysfunction are consequences of limited protein repair systems and slowed protein turnover. When relatively high rates of protein turnover are maintained despite advancing age, damaged proteins are more quickly degraded and replaced, maintaining proteome fidelity. Therefore, maintenance of protein turnover represents an important proteostatic mechanism. However, measurement of protein synthesis without consideration for cell proliferation can result in an incomplete picture, devoid of information about how new proteins are being allocated. Simultaneous measurement of protein and DNA synthesis provides necessary mechanistic insight about proteins apportioned for newly proliferating cells versus for somatic maintenance. Using this approach with a number of murine models of slowed aging shows that, compared to controls, energetic resources are directed more toward somatic maintenance and proteostasis, and away from cell growth and proliferation. In particular, slowed aging models are associated with heightened mechanisms of mitochondrial proteostatic maintenance. Taking cell proliferation into account may explain the paradoxical findings that aging itself and slowed aging interventions can both be characterized by slower rates of protein synthesis. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Lipid anchoring of Arabidopsis phototropin 1 to assess the functional significance of receptor internalization: should I stay or should I go?

PubMed

Preuten, Tobias; Blackwood, Lisa; Christie, John M; Fankhauser, Christian

2015-05-01

The phototropin 1 (phot1) blue light receptor mediates a number of adaptive responses, including phototropism, that generally serve to optimize photosynthetic capacity. Phot1 is a plasma membrane-associated protein, but upon irradiation, a fraction is internalized into the cytoplasm. Although this phenomenon has been reported for more than a decade, its biological significance remains elusive. Here, we use a genetic approach to revisit the prevalent hypotheses regarding the functional importance of receptor internalization. Transgenic plants expressing lipidated versions of phot1 that are permanently anchored to the plasma membrane were used to analyse the effect of internalization on receptor turnover, phototropism and other phot1-mediated responses. Myristoylation and farnesylation effectively prevented phot1 internalization. Both modified photoreceptors were found to be fully functional in Arabidopsis, rescuing phototropism and all other phot1-mediated responses tested. Light-mediated phot1 turnover occurred as in the native receptor. Furthermore, our work does not provide any evidence of a role of phot1 internalization in the attenuation of receptor signalling during phototropism. Our results demonstrate that phot1 signalling is initiated at the plasma membrane. They furthermore indicate that release of phot1 into the cytosol is not linked to receptor turnover or desensitization. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Taste bud cells of adult mice are responsive to Wnt/β-catenin signaling: implications for the renewal of mature taste cells

PubMed Central

Gaillard, Dany; Barlow, Linda A.

2012-01-01

Wnt/β-catenin signaling initiates taste papilla development in mouse embryos, however, its involvement in taste cell turnover in adult mice has not been explored. Here we used the BATGAL reporter mouse model, which carries an engineered allele in which the LacZ gene is expressed in the presence of activated β-catenin, to determine the responsiveness of adult taste bud cells to canonical Wnt signaling. Double immunostaining with markers of differentiated taste cells revealed that a subset of type I, II and III taste cells express β-galactosidase. Using in situ hybridization, we showed that β-catenin activates the transcription of the LacZ gene mainly in intragemmal basal cells that are immature taste cells, identified by their expression of Sonic Hedgehog (Shh). Finally, we showed that β-catenin activity is significantly reduced in taste buds of 25 week-old mice compared to 10 week-old animals. Our data suggest that Wnt/β-catenin signaling may influence taste cell turnover by regulating cell differentiation. Reduced canonical Wnt signaling in older mice could explain in part the loss of taste sensitivity with aging, implicating a possible deficiency in the rate of taste cell renewal. More investigations are now necessary to understand if and how Wnt signaling regulates adult taste cell turnover. PMID:21328519

Taste bud cells of adult mice are responsive to Wnt/β-catenin signaling: implications for the renewal of mature taste cells.

PubMed

Gaillard, Dany; Barlow, Linda A

2011-04-01

Wnt/β-catenin signaling initiates taste papilla development in mouse embryos, however, its involvement in taste cell turnover in adult mice has not been explored. Here we used the BATGAL reporter mouse model, which carries an engineered allele in which the LacZ gene is expressed in the presence of activated β-catenin, to determine the responsiveness of adult taste bud cells to canonical Wnt signaling. Double immunostaining with markers of differentiated taste cells revealed that a subset of Type I, II, and III taste cells express β-galactosidase. Using in situ hybridization, we showed that β-catenin activates the transcription of the LacZ gene mainly in intragemmal basal cells that are immature taste cells, identified by their expression of Sonic Hedgehog (Shh). Finally, we showed that β-catenin activity is significantly reduced in taste buds of 25-week-old mice compared with 10-week-old animals. Our data suggest that Wnt/β-catenin signaling may influence taste cell turnover by regulating cell differentiation. Reduced canonical Wnt signaling in older mice could explain in part the loss of taste sensitivity with aging, implicating a possible deficiency in the rate of taste cell renewal. More investigations are now necessary to understand if and how Wnt signaling regulates adult taste cell turnover. Copyright © 2011 Wiley-Liss, Inc.

Short-Term Effects of Tillage Practices on Soil Organic Carbon Turnover Assessed by δ 13C Abundance in Particle-Size Fractions of Black Soils from Northeast China

PubMed Central

Zhang, Xiaoping; Chen, Xuewen

2014-01-01

The combination of isotope trace technique and SOC fractionation allows a better understanding of SOC dynamics. A five-year tillage experiment consisting of no-tillage (NT) and mouldboard plough (MP) was used to study the changes in particle-size SOC fractions and corresponding δ 13C natural abundance to assess SOC turnover in the 0–20 cm layer of black soils under tillage practices. Compared to the initial level, total SOC tended to be stratified but showed a slight increase in the entire plough layer under short-term NT. MP had no significant impacts on SOC at any depth. Because of significant increases in coarse particulate organic carbon (POC) and decreases in fine POC, total POC did not remarkably decrease under NT and MP. A distinct increase in silt plus clay OC occurred in NT plots, but not in MP plots. However, the δ 13C abundances of both coarse and fine POC increased, while those of silt plus clay OC remained almost the same under NT. The C derived from C3 plants was mainly associated with fine particles and much less with coarse particles. These results suggested that short-term NT and MP preferentially enhanced the turnover of POC, which was considerably faster than that of silt plus clay OC. PMID:25162052

Experiment K-6-17. Structural changes and cell turnover in the rats small intestine induced by spaceflight

NASA Technical Reports Server (NTRS)

Phillips, R. W.; Sawyer, H. R.; Smirnov, K. V.

1990-01-01

The purpose of this project was to test the hypothesis that the generalized, whole body decrease in synthetic activity associated with microgravity conditions of space flight as evidenced by negative nitrogen balance and muscle atrophy (Nicogossian and Parker, 1982; Oganov, 1981), as well as inhibited lymphocyte proliferation (Bechler and Cogoli, 1986), would be evident in cells characterized by a rapid rate of turnover. As a model, researchers chose to study the turnover of mucosal cells lining the jejunum of the small intestine, since these cells are among the most rapidly proliferating in the body. Under normal conditions, epithelial cells that line the small intestine are continually produced in the crypts of Lieberkuhn. These cells migrate out of the crypts onto intestinal villi, are progressively pushed up the villus as new crypt cells are formed, and ultimately reach the tip of villi where they are then descquamated. In rats, the entire process, from initial proliferation in crypts to desquamation, takes approximately 2 days (Cairnie et al., 1965; Lipkin, 1973). In this study, researchers determined the mitotic index for mucosal cells lining the proximal, middle, and distal regions of the jejunum in rats from three treatment groups (synchronous control, vivarium control and flight), and measured the depth of the crypts of Lieberkuhn and the length of villi present in each of the three jejunal regions sampled.

Persistence of subclinical deformed wing virus infections in honeybees following Varroa mite removal and a bee population turnover

PubMed Central

Semberg, Emilia; Forsgren, Eva; de Miranda, Joachim R.

2017-01-01

Deformed wing virus (DWV) is a lethal virus of honeybees (Apis mellifera) implicated in elevated colony mortality rates worldwide and facilitated through vector transmission by the ectoparasitic mite Varroa destructor. Clinical, symptomatic DWV infections are almost exclusively associated with high virus titres during pupal development, usually acquired through feeding by Varroa mites when reproducing on bee pupae. Control of the mite population, generally through acaricide treatment, is essential for breaking the DWV epidemic and minimizing colony losses. In this study, we evaluated the effectiveness of remedial mite control on clearing DWV from a colony. DWV titres in adult bees and pupae were monitored at 2 week intervals through summer and autumn in acaricide-treated and untreated colonies. The DWV titres in Apistan treated colonies was reduced 1000-fold relative to untreated colonies, which coincided with both the removal of mites and also a turnover of the bee population in the colony. This adult bee population turnover is probably more critical than previously realized for effective clearing of DWV infections. After this initial reduction, subclinical DWV titres persisted and even increased again gradually during autumn, demonstrating that alternative non-Varroa transmission routes can maintain the DWV titres at significant subclinical levels even after mite removal. The implications of these results for practical recommendations to mitigate deleterious subclinical DWV infections and improving honeybee health management are discussed. PMID:28686725

Eldecalcitol normalizes bone turnover markers regardless of their pre-treatment levels.

PubMed

Shiraki, Masataka; Saito, Hitoshi; Matsumoto, Toshio

2012-09-01

Three-year treatment with eldecalcitol has been shown to improve lumbar and total hip bone mineral density (BMD), decrease bone turnover markers, and lower the incidences of vertebral and wrist fractures in patients with osteoporosis more than with treatment with alfacalcidol under vitamin D repletion. The purpose of this study was to determine whether there was a risk of eldecalcitol causing severely suppressed bone turnover in osteoporosis patients with low pre-treatment levels of bone turnover markers. Post-hoc analysis was conducted on the data from a 3-year, randomized, double-blind, active-comparator, clinical trial of eldecalcitol versus alfacalcidol under vitamin D repletion conducted in Japan. Enrolled patients with baseline measurements of bone turnover markers were stratified into tertiles according to their pre-treatment levels of serum bone-specific alkaline phosphatase, serum procollagen type I N-terminal propeptide, or urinary collagen-N-telopeptide. Eldecalcitol treatment rapidly reduced bone turnover markers, and kept them within the normal range. However, in the patients whose baseline values for bone turnover were low, eldecalcitol treatment did not further reduce bone turnover markers during the 3-year treatment period. Further long-term observation may be required to reach the conclusion. CLINICALTRIALS.GOV NUMBER: NCT00144456. Eldecalcitol normalizes, but does not overly suppress, bone turnover regardless of baseline levels of bone turnover markers. Thus, it is unlikely that eldecalcitol treatment will increase the risk of severely suppressed bone turnover and therefore deterioration of bone quality, at least for a treatment duration of 3 years.

The Influence of Professional Identity, Job Satisfaction, and Work Engagement on Turnover Intention among Township Health Inspectors in China.

PubMed

Zhang, Wenjie; Meng, Hongdao; Yang, Shujuan; Liu, Danping

2018-05-14

Health inspectors are part of the public health workforce in China, and its shortage has been identified as an urgent priority that should be addressed. Turnover is one of the main contributors to the shortage problem. This research assessed the influence of professional identity, job satisfaction and work engagement on turnover intention of township health inspectors and explored the intermediary effect of job satisfaction and work engagement between professional identity and turnover intention among township health inspectors in China. Data were collected from 2426 township health inspectors in Sichuan Province, China. We used structural equation modeling (SEM) to test the hypothesized relationship among the variables. Results showed that a total of 11.3% of participants had a high turnover intention and 34.0% of participants had a medium turnover intention. Job satisfaction had a direct negative effect on turnover intention (β = -0.38, p < 0.001), work engagement had a direct negative effect on turnover intention (β = -0.13, p < 0.001), and professional identity had an indirect negative effect on turnover intention through the mediating effect of job satisfaction and work engagement. Our results strongly confirmed that professional identity, job satisfaction and work engagement were strong predicators of turnover intention. According to the results, desirable work environment, quality facilities, fair compensation and adequate advancement opportunities should be emphasized to improve job satisfaction. The turnover intention of health inspectors could be reduced through improving professional identity, enhancing job satisfaction and work engagement.

A Prospective Examination of Clinician and Supervisor Turnover Within the Context of Implementation of Evidence-Based Practices in a Publicly-Funded Mental Health System.

PubMed

Beidas, Rinad S; Marcus, Steven; Wolk, Courtney Benjamin; Powell, Byron; Aarons, Gregory A; Evans, Arthur C; Hurford, Matthew O; Hadley, Trevor; Adams, Danielle R; Walsh, Lucia M; Babbar, Shaili; Barg, Frances; Mandell, David S

2016-09-01

Staff turnover rates in publicly-funded mental health settings are high. We investigated staff and organizational predictors of turnover in a sample of individuals working in an urban public mental health system that has engaged in a system-level effort to implement evidence-based practices. Additionally, we interviewed staff to understand reasons for turnover. Greater staff burnout predicted increased turnover, more openness toward new practices predicted retention, and more professional recognition predicted increased turnover. Staff reported leaving their organizations because of personal, organizational, and financial reasons; just over half of staff that left their organization stayed in the public mental health sector. Implications include an imperative to focus on turnover, with a particular emphasis on ameliorating staff burnout.

Mental Health and Turnover Following an Initial Term of Military Service

DTIC Science & Technology

2012-07-01

enlistments reached such levels that the Marine Corps was forced to significantly increase its selective re-enlistment bonuses .’^ These findings indicate a...Their Consequences and Services to Assist Recov- ery. Santa Monica, CA, RAND Corporation, Center for Military Health Policy Research, 2008. 4. Carbone ...Assess 1999; 72: 256-65. 5. Cigrang JA, Carbone EG, Todd S, Fielder E: Mental health attrition from Air Force basic military training. Mil Med 1999; 163

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor.

PubMed

Esler, Murray; Lambert, Elisabeth; Alvarenga, Marlies; Socratous, Florentia; Richards, Jeff; Barton, David; Pier, Ciaran; Brenchley, Celia; Dawood, Tye; Hastings, Jacqueline; Guo, Ling; Haikerwal, Deepak; Kaye, David; Jennings, Garry; Kalff, Victor; Kelly, Michael; Wiesner, Glen; Lambert, Gavin

2007-08-01

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.

Elevated CO2 and water addition enhance nitrogen turnover in grassland plants with implications for temporal stability.

PubMed

Dijkstra, Feike A; Carrillo, Yolima; Blumenthal, Dana M; Mueller, Kevin E; LeCain, Dan R; Morgan, Jack A; Zelikova, Tamara J; Williams, David G; Follett, Ronald F; Pendall, Elise

2018-05-01

Temporal variation in soil nitrogen (N) availability affects growth of grassland communities that differ in their use and reuse of N. In a 7-year-long climate change experiment in a semi-arid grassland, the temporal stability of plant biomass production varied with plant N turnover (reliance on externally acquired N relative to internally recycled N). Species with high N turnover were less stable in time compared to species with low N turnover. In contrast, N turnover at the community level was positively associated with asynchrony in biomass production, which in turn increased community temporal stability. Elevated CO 2 and summer irrigation, but not warming, enhanced community N turnover and stability, possibly because treatments promoted greater abundance of species with high N turnover. Our study highlights the importance of plant N turnover for determining the temporal stability of individual species and plant communities affected by climate change. © 2018 John Wiley & Sons Ltd/CNRS.

The relationship between clinician turnover and adolescent treatment outcomes: An examination from the client perspective

PubMed Central

Garner, Bryan R.; Funk, Rodney R.; Hunter, Brooke D.

2012-01-01

The turnover of substance use disorder (SUD) treatment staff has been assumed to adversely impact treatment effectiveness, yet only limited research has empirically examined this assumption. Representing an extension of prior organizational-level analyses of the impact of staff turnover on client outcomes, this study examined the impact of SUD clinician turnover on adolescent treatment outcomes using a client perspective. Multilevel regression analysis did reveal that relative to those adolescents who did not experience clinician turnover, adolescents who experienced both direct and indirect clinician turnover reported a significantly higher percentage of days using alcohol or drugs at 6-month follow-up. However, clinician turnover was not found to have significant associations (negative or positive) with the other five treatment outcomes examined (e.g., substance-related problems, involvement in illegal activity). Thus, consistent with our prior findings, the current study provides additional evidence that turnover of SUD clinicians is not necessarily associated with adverse treatment outcomes. PMID:23083980

Examining the temporal relationship between psychological climate, work attitude, and staff turnover.

PubMed

Garner, Bryan R; Hunter, Brooke D

2013-02-01

Relative to the broader industrial-organizational (I-O) psychology field, research on the turnover of substance use disorder (SUD) treatment staff is in its infancy. Despite its long and rich history, recent reviews of the turnover literature within I-O psychology have noted that there remains considerable room for improvement. In particular, recommendations have been made for research that considers time in the turnover process and explores more distal causes of staff turnover. Addressing these gaps, this article examined the temporal relationship between latent measures of psychological climate, work attitude, and staff turnover. Using data from 95 SUD treatment staff clustered within 29 treatment organizations, multilevel discrete-time survival analyses revealed that a latent measure of work attitude (e.g., job satisfaction, pay satisfaction, turnover intentions) fully mediated the temporal relationship between latent measures of psychological climate (e.g., supervisor support, coworker support, role conflict) and subsequent staff turnover. Copyright © 2013 Elsevier Inc. All rights reserved.

Determination of the electromechanical coupling factor of gallium orthophosphate (GaPO4) and its influence on resonance-frequency temperature dependencies.

PubMed

Nosek, Jaroslav; Pustka, Martin

2006-01-01

The quartz homeotype gallium orthophosphate (GaPO4) is a representative of piezoelectric single crystals of large electromechanical coupling factor. It is known that its coupling factor kappa26 associated with the resonators vibrating in the thickness-shear mode is approximately two times greater than that of quartz. This property increases the spacing between the series and parallel resonance frequencies of resonators, as well as the difference between the resonance frequency temperature dependencies of the fundamental and harmonic resonance frequencies of resonators vibrating in the thickness-shear mode. In this paper, the methods for determination of the coupling factor kappa26 are presented, and the computed values are compared with the measured ones. The influence of the coupling factor to the resonance-frequency temperature dependencies of the fundamental and third harmonics of selected rotated Y-cut GaPO4 resonators vibrating in the thickness-shear mode is presented. The purely elastic case for a laterally unbounded plate, which corresponds closely to the limiting case of high harmonic resonance frequency-temperature behavior was assumed for the calculations. The computed temperature coefficients for the Y-cut orientation and calculated turnover point temperatures TTP for different (YX1) orientations are presented.

Staff Turnover in Assertive Community Treatment (Act) Teams: The Role of Team Climate.

PubMed

Zhu, Xi; Wholey, Douglas R; Cain, Cindy; Natafgi, Nabil

2017-03-01

Staff turnover in Assertive Community Treatment (ACT) teams can result in interrupted services and diminished support for clients. This paper examines the effect of team climate, defined as team members' shared perceptions of their work environment, on turnover and individual outcomes that mediate the climate-turnover relationship. We focus on two climate dimensions: safety and quality climate and constructive conflict climate. Using survey data collected from 26 ACT teams, our analyses highlight the importance of safety and quality climate in reducing turnover, and job satisfaction as the main mediator linking team climate to turnover. The findings offer practical implications for team management.

Organizational and environmental effects on voluntary and involuntary turnover.

PubMed

Donoghue, Christopher; Castle, Nicholas G

2007-01-01

There are few studies of voluntary and involuntary turnover in the nursing home literature. Previous research in this area has focused mainly on the linear effects of individual and organizational characteristics on total turnover. The purpose of this study was to examine both linear and nonlinear effects of organizational and environmental conditions on voluntary and involuntary nursing home staff turnover. We analyzed both primary and secondary data on 854 nursing homes in six states. A negative binomial regression model was used to study both linear and curvilinear effects of organizational and environmental factors on voluntary and involuntary turnover among registered nurses, licensed practical nurses, and nurse aides. Staffing levels and deficiency citations were the organizational characteristics most consistently linked with turnover among all nurse types. Links were also found between unemployment and type of location (urban or rural) and turnover, indicating that the economic environment is influential for retention. The results of this study support the notion that policy makers need to consider both the organization and the environment when evaluating the nature of nursing home staff turnover. The findings also offer further evidence that the antecedents of voluntary and involuntary turnover are not necessarily the same.

Nurse turnover in New Zealand: costs and relationships with staffing practises and patient outcomes.

PubMed

North, Nicola; Leung, William; Ashton, Toni; Rasmussen, Erling; Hughes, Frances; Finlayson, Mary

2013-04-01

To determine the rates and costs of nurse turnover, the relationships with staffing practises, and the impacts on outcomes for nurses and patients. In the context of nursing shortages, information on the rates and costs of nursing turnover can improve nursing staff management and quality of care. Quantitative and qualitative data were collected prospectively for 12 months. A re-analysis of these data used descriptive statistics and correlational analysis techniques. The cost per registered nurse turnover represents half an average salary. The highest costs were related to temporary cover, followed by productivity loss. Both are associated with adverse patient events. Flexible management of nursing resources (staffing below budgeted levels and reliance on temporary cover), and a reliance on new graduates and international recruitment to replace nurses who left, contributed to turnover and costs. Nurse turnover is embedded in staffing levels and practises, with costs attributable to both. A culture of turnover was found that is inconsistent with nursing as a knowledge workforce. Nurse managers did not challenge flexible staffing practices and high turnover rates. Information on turnover and costs is needed to develop strategies that retain nurses as knowledge-based workers. © 2012 Blackwell Publishing Ltd.

Spatial variation in the climatic predictors of species compositional turnover and endemism

PubMed Central

Di Virgilio, Giovanni; Laffan, Shawn W; Ebach, Malte C; Chapple, David G

2014-01-01

Previous research focusing on broad-scale or geographically invariant species-environment dependencies suggest that temperature-related variables explain more of the variation in reptile distributions than precipitation. However, species–environment relationships may exhibit considerable spatial variation contingent upon the geographic nuances that vary between locations. Broad-scale, geographically invariant analyses may mask this local variation and their findings may not generalize to different locations at local scales. We assess how reptile–climatic relationships change with varying spatial scale, location, and direction. Since the spatial distributions of diversity and endemism hotspots differ for other species groups, we also assess whether reptile species turnover and endemism hotspots are influenced differently by climatic predictors. Using New Zealand reptiles as an example, the variation in species turnover, endemism and turnover in climatic variables was measured using directional moving window analyses, rotated through 360°. Correlations between the species turnover, endemism and climatic turnover results generated by each rotation of the moving window were analysed using multivariate generalized linear models applied at national, regional, and local scales. At national-scale, temperature turnover consistently exhibited the greatest influence on species turnover and endemism, but model predictive capacity was low (typically r2 = 0.05, P < 0.001). At regional scales the relative influence of temperature and precipitation turnover varied between regions, although model predictive capacity was also generally low. Climatic turnover was considerably more predictive of species turnover and endemism at local scales (e.g., r2 = 0.65, P < 0.001). While temperature turnover had the greatest effect in one locale (the northern North Island), there was substantial variation in the relative influence of temperature and precipitation predictors in the remaining four locales. Species turnover and endemism hotspots often occurred in different locations. Climatic predictors had a smaller influence on endemism. Our results caution against assuming that variability in temperature will always be most predictive of reptile biodiversity across different spatial scales, locations and directions. The influence of climatic turnover on the species turnover and endemism of other taxa may exhibit similar patterns of spatial variation. Such intricate variation might be discerned more readily if studies at broad scales are complemented by geographically variant, local-scale analyses. PMID:25473479

Numbers of simultaneous turnovers calculated from anesthesia or operating room information management system data.

PubMed

Dexter, Franklin; Marcon, Eric; Aker, John; Epstein, Richard H

2009-09-01

More personnel are needed to turn over operating rooms (ORs) promptly when there are more simultaneous turnovers. Anesthesia and/or OR information management system data can be analyzed statistically to quantify simultaneous turnovers to evaluate whether to add an additional turnover team. Data collected for each case at a six OR facility were room, date of surgery, time of patient entry into the OR, and time of patient exit from the OR. The number of simultaneous turnovers was calculated for each 1 min of 122 4-wk periods. Our end point was the reduction in the daily minutes of simultaneous turnovers exceeding the number of teams caused by the addition of a team. Increasing from two turnover teams to three teams reduced the mean daily minutes of simultaneous turnovers exceeding the numbers of teams by 19 min. The ratio of 19 min to 8 h valued the time of extra personnel as 4.0% of the time of OR staff, surgeons, and anesthesia providers. Validity was suggested by other methods of analyses also suggesting staffing for three simultaneous turnovers. Discrete-event simulation showed that the reduction in daily minutes of turnover times from the addition of a team would likely match or exceed the reduction in the daily minutes of simultaneous turnovers exceeding the numbers of teams. Confidence intervals for daily minutes of turnover times achieved by increasing from two to three teams were calculated using successive 4-wk periods. The distribution was sufficiently close to normal that accurate confidence intervals could be calculated using Student's t distribution (Lilliefors' test P = 0.58). Analysis generally should use 13 4-wk periods as increasing the number of periods from 6 to 13 significantly reduced the coefficient of variation of the averages but not increasing the number of periods from 6 to 9 or from 9 to 13. The number of simultaneous turnovers can be calculated for each 1 min over 1 yr. The reduction in the daily minutes of simultaneous turnovers exceeding the number of teams achieved by the addition of a turnover team can be averaged over the year's 13 4-wk periods to provide insight as to the value (or not) of adding an additional team.

Consequences of client-initiated workplace violence: the role of fear and perceived prevention.

PubMed

Mueller, Sonja; Tschan, Franziska

2011-04-01

The authors suggested and tested a model of the consequences of client-initiated workplace violence, introducing perceived prevention of violence and perceived coping ability as factors that reduce fear of future violence and mitigate negative personal and organizational consequences. Survey data from 330 frontline staff from job centers and social security offices were analyzed using structural equation modeling. The data supported the model and confirmed the central role of the fear of violence with regard to outcomes such as psychological and physical well-being or irritability. Results point further to perceived prevention of violence as an important factor that influences fear levels in different ways, predicts turnover intentions, and should therefore be considered when managers aim to address the consequences of client-initiated violence and threats.

Factors Related to Turnover among Mental Health Workers.

ERIC Educational Resources Information Center

Tang, Thomas Li-Ping

In view of the extremely high turnover among corporation recruits, there is growing and justified interest in having organizations identify the causes of turnover and possible ways of reducing it. Many studies have examined different variables related to turnover, including organizational commitment, career commitment, job satisfaction, and…

Turnover Begets Turnover

ERIC Educational Resources Information Center

Castle, Nicholas G.

2005-01-01

Purpose: This study examined the association between turnover of caregivers and turnover of nursing home top management. The top managers examined were administrators and directors of nursing, and the caregivers examined were registered nurses, licensed practical nurses, and nurse aides. Design and Methods: The data came from a survey of 419…

The role of job satisfaction, work engagement, self-efficacy and agentic capacities on nurses' turnover intention and patient satisfaction.

PubMed

De Simone, Silvia; Planta, Anna; Cicotto, Gianfranco

2018-02-01

Nurses' voluntary turnover is a worrying global phenomenon which affects service quality. Retaining nursing staff within a hospital is important to eliminate the negative influence of voluntary turnover on the quality of care and organisation costs. This research helps explain nurses' voluntary turnover by analysing the role of self-efficacy, agentic capacities, job satisfaction, and work engagement on hospital turnover intention, and to study the relationships between these variables and patient satisfaction. This study gathered data from 194 nurses and 181 patients from 22 inpatient wards at two hospitals in southern Italy. Correlation analysis revealed that job satisfaction, work engagement, self-efficacy and agentic capacities were positively interrelated and negatively correlated with turnover intention. Path analysis showed that self-efficacy, some agentic capacities (anticipation and self-regulation), job satisfaction, and work engagement had direct or indirect effects on nurses' turnover intention, and that job satisfaction exerted a stronger effect on turnover intention. Also, patient satisfaction was positively correlated with nurses' job satisfaction, work engagement, self-efficacy, self-regulation and anticipation and negatively correlated with nurses' turnover intention. Results highlighted the importance of implementing actions (for example through feedforward methodology and the goal setting technique) to improve self-efficacy, self-regulation skill, work engagement and job satisfaction in order to reduce nurses' turnover intention and increase patient satisfaction with nursing care. Copyright © 2017 Elsevier Inc. All rights reserved.

Nurse knowledge, work environment, and turnover in highly specialized pediatric end-of-life care

PubMed Central

Lindley, Lisa C.; Cozad, Melanie J.

2016-01-01

Objective To examine the relationship between nurse knowledge and work environment and Registered Nurse (RN) turnover in perinatal hospice and palliative care organizations. Methods Using nurse intellectual capital theory, a multivariate analysis was conducted with 2007 National Home and Hospice Care Survey data. Results Perinatal hospice and palliative care organizations experienced a 5% turnover rate. The professional experience of advanced practice nurses (APNs) was significantly related to turnover among RNs (β= −0.032, P< 0.05). Compared to organizations with no APNs professional experience, clinical nurse specialists and nurse practitioners significantly reduced RN turnover by 3-percentage points. No other nurse knowledge or work environment variables were associated with RN turnover. Several of the control variables were also associated with RN turnover in the study: organizations serving micropolitan (β= −0.041, P< 0.05) and rural areas (β= −0.037, P< 0.05) had lower RN turnover, compared to urban areas. Organizations with a technology climate where nurses used electronic medical records had a higher turnover rate than those without (β= 0.036, P< 0.05). Conclusions The findings revealed that advanced professional experience in the form of APNs were associated with reductions in RN turnover. This suggests that having a clinical nurse specialist or nurse practitioner on staff may provide knowledge and experience to other RNs, creating stability within the organization. PMID:27188758

Measuring worker turnover in long-term care: lessons from the better jobs better care demonstration.

PubMed

Barry, Theresa Teta; Kemper, Peter; Brannon, S Diane

2008-06-01

Turnover among direct-care workers (DCWs) continues to be a challenge in long-term care. Both policy makers and provider organizations recognize this issue as a major concern and are designing efforts to reduce turnover among these workers. However, there is currently no standardized method of measuring turnover to define the scope of the problem or to assess the effectiveness of interventions. This article draws on our experience of the Better Jobs Better Care Demonstration (BJBC) to explicate some important issues in measuring and interpreting turnover related to interventions designed to improve DCW jobs. We used turnover data from a selected group of BJBC providers (N = 9) to demonstrate some of the measurement issues we uncovered in developing a turnover tracking system for BJBC. We also illustrate how the data elements collected in the tracking system make it possible to construct measures that are useful at both policy and practice levels. Differences in definitions of turnover and the data elements used to construct the measure can have large effects on turn over rates, how they are used, and what they mean. Policy makers, researchers, and managers who need comparative turnover information to address the impending demand for DCWs should be aware that turnover measures differ, and they should take steps to ensure that measures they use have common definitions and data elements.

On-call work and physicians' turnover intention: the moderating effect of job strain.

PubMed

Heponiemi, Tarja; Presseau, Justin; Elovainio, Marko

2016-01-01

Physician shortage and turnover are major problems worldwide. On-call duties may be among the risk factors of high turnover rates among physicians. We investigated whether having on-call duties is associated with physicians' turnover intention and whether job strain variables moderate this association. The present study was a cross-sectional questionnaire study among 3324 (61.6% women) Finnish physicians. The analyses were conducted using analyses of covariance adjusted for age, gender, response format, specialization status and employment sector. The results showed that job strain moderated the association between being on-call and turnover intention. The highest levels of turnover intention were among those who had on-call duties and high level of job strain characterized by high demands and low control opportunities. The lowest levels of turnover intention were among those who were not on-call and who had low strain involving low demands and high control. Also, job demands moderated the association between being on-call and turnover intention; turnover intention levels were higher among those with on-call duties and high demands than those being on-call and low demands. To conclude, working on-call was related to physicians' turnover intention particularly in those with high job strain. Health care organizations should focus more attention on working arrangements and scheduling of on-call work, provide a suitable working pace and implement means to increase physicians' participation and control over their job.

A conceptual and empirical analysis of the cognitive ability-voluntary turnover relationship.

PubMed

Maltarich, Mark A; Nyberg, Anthony J; Reilly, Greg

2010-11-01

Despite much research into cognitive ability as a selection tool and a separate large literature on the causes of voluntary turnover, little theoretical or empirical work connects the two. We propose that voluntary turnover is also a potentially key outcome of cognitive ability. Incorporating ideas from the person-environment fit literature and those regarding push and pull influences on turnover, we posit a theoretical connection between cognitive ability and voluntary turnover that addresses both why and how voluntary turnover is related to cognitive ability. Integrating data from 3 different sources, our empirical analyses support the theoretical perspective that the relationship between cognitive ability and voluntary turnover depends on the cognitive demands of the job. When the cognitive demands of a job are high, our findings support the hypothesized curvilinear relationship between cognitive ability and voluntary turnover, such that employees of higher and lower cognitive ability are more likely than medium cognitive ability employees to leave voluntarily. With regard to jobs with low cognitive demands, our data are more consistent with a negative linear relationship between cognitive ability and voluntary turnover, such that higher cognitive ability employees are less likely to leave voluntarily. We also examine the role of job satisfaction, finding that job satisfaction is more strongly linked to voluntary turnover in jobs with high cognitive demands. (c) 2010 APA, all rights reserved.

Differential challenge stressor-hindrance stressor relationships with job attitudes, turnover intentions, turnover, and withdrawal behavior: a meta-analysis.

PubMed

Podsakoff, Nathan P; LePine, Jeffery A; LePine, Marcie A

2007-03-01

In this article, a 2-dimensional work stressor framework is used to explain inconsistencies in past research with respect to stressor relationships with retention-related criteria. Results of meta-analyses of 183 independent samples indicated that whereas hindrance stressors had dysfunctional relationships with these criteria (negative relationships with job satisfaction and organizational commitment and positive relationships with turnover intentions, turnover, and withdrawal behavior), relationships with challenge stressors were generally the opposite (positive relationships with job satisfaction and organizational commitment and negative relationships with turnover intentions and turnover). Results also suggested that the differential relationships between challenge stressors and hindrance stressors and the more distal criteria (withdrawal behavior and turnover) were due, in part, to the mediating effects of job attitudes. (c) 2007 APA, all rights reserved.

Transformational leadership moderates the relationship between emotional exhaustion and turnover intention among community mental health providers.

PubMed

Green, Amy E; Miller, Elizabeth A; Aarons, Gregory A

2013-08-01

Public sector mental health care providers are at high risk for burnout and emotional exhaustion which negatively affect job performance and client satisfaction with services. Few studies have examined ways to reduce these associations, but transformational leadership may have a positive effect. We examine the relationships between transformational leadership, emotional exhaustion, and turnover intention in a sample of 388 community mental health providers. Emotional exhaustion was positively related to turnover intention, and transformational leadership was negatively related to both emotional exhaustion and turnover intention. Transformational leadership moderated the relationship between emotional exhaustion and turnover intention, indicating that having a transformational leader may buffer the effects of providers' emotional exhaustion on turnover intention. Investing in transformational leadership development for supervisors could reduce emotional exhaustion and turnover among public sector mental health providers.

Transformational Leadership Moderates the Relationship between Emotional Exhaustion and Turnover Intention among Community Mental Health Providers

PubMed Central

Green, Amy E.; Miller, Elizabeth A.; Aarons, Gregory A.

2014-01-01

Public sector mental health care providers are at high risk for burnout and emotional exhaustion which negatively affect job performance and client satisfaction with services. Few studies have examined ways to reduce these associations, but transformational leadership may have a positive effect. We examine the relationships between transformational leadership, emotional exhaustion, and turnover intention in a sample of 388 community mental health providers. Emotional exhaustion was positively related to turnover intention, and transformational leadership was negatively related to both emotional exhaustion and turnover intention. Transformational leadership moderated the relationship between emotional exhaustion and turnover intention, indicating that having a transformational leader may buffer the effects of providers’ emotional exhaustion on turnover intention. Investing in transformational leadership development for supervisors could reduce emotional exhaustion and turnover among public sector mental health providers. PMID:22052429

A prospective examination of clinician and supervisor turnover within the context of implementation of evidence-based practices in a publicly-funded mental health system

PubMed Central

Marcus, Steven; Wolk, Courtney Benjamin; Powell, Byron; Aarons, Gregory A.; Evans, Arthur C.; Hurford, Matthew O.; Hadley, Trevor; Adams, Danielle R.; Walsh, Lucia M.; Babbar, Shaili; Barg, Frances; Mandell, David S.

2015-01-01

Staff turnover rates in publicly-funded mental health settings are high. We investigated staff and organizational predictors of turnover in a sample of individuals working in an urban public mental health system that has engaged in a system-level effort to implement evidence-based practices. Additionally, we interviewed staff to understand reasons for turnover. Greater staff burnout predicted increased turnover, more openness toward new practices predicted retention, and more professional recognition predicted increased turnover. Staff reported leaving their organizations because of personal, organizational, and financial reasons; just over half of staff that left their organization stayed in the public mental health sector. Implications include an imperative to focus on turnover, with a particular emphasis on ameliorating staff burnout. PMID:26179469

The Influence of Professional Identity, Job Satisfaction, and Work Engagement on Turnover Intention among Township Health Inspectors in China

PubMed Central

Zhang, Wenjie; Meng, Hongdao; Liu, Danping

2018-01-01

Health inspectors are part of the public health workforce in China, and its shortage has been identified as an urgent priority that should be addressed. Turnover is one of the main contributors to the shortage problem. This research assessed the influence of professional identity, job satisfaction and work engagement on turnover intention of township health inspectors and explored the intermediary effect of job satisfaction and work engagement between professional identity and turnover intention among township health inspectors in China. Data were collected from 2426 township health inspectors in Sichuan Province, China. We used structural equation modeling (SEM) to test the hypothesized relationship among the variables. Results showed that a total of 11.3% of participants had a high turnover intention and 34.0% of participants had a medium turnover intention. Job satisfaction had a direct negative effect on turnover intention (β = −0.38, p < 0.001), work engagement had a direct negative effect on turnover intention (β = −0.13, p < 0.001), and professional identity had an indirect negative effect on turnover intention through the mediating effect of job satisfaction and work engagement. Our results strongly confirmed that professional identity, job satisfaction and work engagement were strong predicators of turnover intention. According to the results, desirable work environment, quality facilities, fair compensation and adequate advancement opportunities should be emphasized to improve job satisfaction. The turnover intention of health inspectors could be reduced through improving professional identity, enhancing job satisfaction and work engagement. PMID:29757985

[A study of work values, professional commitment, turnover intention and related factors among clinical nurses].

PubMed

Wang, Kuei-Ying; Chou, Chuan-Chiang; Huang, Jui-Lan

2010-02-01

The high rate of turnover in nursing positions is a global problem. There have been few studies done addressing the relationship between work values and nurse turnover intention. The purpose of this study was to explore the relationship between work values, professional commitment and turnover intention among clinical nurses. A cross-sectional survey was conducted between February 1st to March 10th, 2008 on a convenience sample of nurses, all of whom had at least a half year of work experience at one of four teaching hospitals in Taiwan. A total of 289 valid responses were received, with a response rate of 96.3%. Major findings included: (1) Nurses who were older, had more years of school, had worked more years, held specific job duties, earned a higher salary, held Buddhist beliefs, or were married with two or more children presented higher work values and professional commitment and lower turnover intention; (2) As a group, total work values and professional commitment scores corresponded negatively with turnover intention scores; (3) Significant factors affecting turnover intent in clinical nurses included professional commitment, institution characteristics, Buddhist beliefs and salary. These four variables accounted for 52.2% of the variation in turnover intention. This study indicated that nurses with higher work values and professional commitment tend to exhibit less turnover intention. It is highly recommended to develop strategies to bolster the teaching of altruistic values and professional commitment in nursing education in order to reduce turnover intent. Also, further studies on the influence of religious beliefs and organizational attributes on nurse turnover intentions are also suggested.

Workplace experiences and turnover intention among adult survivors of childhood cancer.

PubMed

Crom, Deborah B; Ness, Kirsten K; Martinez, Larry R; Hebl, Michelle R; Robison, Leslie L; Hudson, Melissa M; Brinkman, Tara M

2018-03-17

The purpose of this study was to investigate workplace experiences and turnover intention (consideration of leaving or changing a job) and to examine factors associated with turnover intention among survivors. Adult survivors of childhood cancer with a history of employment (n = 289) completed measures of workplace experiences (n = 50, 18-29 years; n = 183, 30-44 years; n = 56; > 45 years of age at follow-up). Turnover intention was assessed using three items from the Job Satisfaction Scale. Responses were dichotomized as reflecting high vs. low turnover intention. Path analysis was used to estimate the influence of demographic characteristics, treatment exposures (cranial radiation therapy [CRT]), and workplace experiences on turnover intention. Thirty percent of survivors reported high turnover intention (95% CL, 25 to 36%). Exposure to CRT (P = 0.003), older attained age (P < 0.001), experiencing formal workplace discrimination (P = 0.008), and having lower continuance (P < 0.001) or affective commitment (P < 0.001) were associated with high turnover intention among survivors. Informal discrimination, mediated through job satisfaction, also influenced survivors' reported intent to leave their jobs. One third of adult survivors of childhood cancer report turnover intention, which is related to their cancer treatment, but more temporally proximal, workplace discrimination. Additional research is needed to understand the consequences of turnover intention among survivors. Survivors and their health care providers should be aware of legislative policies related to workplace discrimination (e.g., American with Disabilities Act) and related implications for job turnover.

Reducing turnover is not enough: The need for proficient organizational cultures to support positive youth outcomes in child welfare.

PubMed

Williams, Nathaniel J; Glisson, Charles

2013-11-01

High caseworker turnover has been identified as a factor in the poor outcomes of child welfare services. However, almost no empirical research has examined the relationship between caseworker turnover and youth outcomes in child welfare systems and there is an important knowledge gap regarding whether, and how, caseworker turnover relates to outcomes for youth. We hypothesized that the effects of caseworker turnover are moderated by organizational culture such that reduced caseworker turnover is only associated with improved youth outcomes in organizations with proficient cultures. The study applied hierarchical linear models (HLM) analysis to the second National Survey of Child and Adolescent Well-being (NSCAW II) with a U.S. nationwide sample of 2,346 youth aged 1.5- to 18-years-old and 1,544 caseworkers in 73 child welfare agencies. Proficient organizational culture was measured by caseworkers' responses to the Organizational Social Context (OSC) measure; staff turnover was reported by the agencies' directors; and youth outcomes were measured as total problems in psychosocial functioning with the Child Behavior Checklist (CBCL) completed by the youths' caregivers at intake and at 18 month follow-up. The association between caseworker turnover and youth outcomes was moderated by organizational culture. Youth outcomes were improved with lower staff turnover in proficient organizational cultures and the best outcomes occurred in organizations with low turnover and high proficiency. To be successful, efforts to improve child welfare services by lowering staff turnover must also create proficient cultures that expect caseworkers to be competent and responsive to the needs of the youth and families they serve.

Using Turnover as a Recruitment Strategy

ERIC Educational Resources Information Center

Duncan, Sandra

2009-01-01

Teacher turnover is notoriously high in the field of early childhood education with an estimated 33% of staff exiting the workplace each year. Turnover is costly. Not only do high levels of turnover negatively impact children's growth and development, it also erodes the program's economic stability and wherewithal to provide effective operations…

Blind Spots: Small Rural Communities and High Turnover in the Superintendency

ERIC Educational Resources Information Center

Kamrath, Barry; Brunner, C. Cryss

2014-01-01

This article examines high superintendency turnover through rural community members' perceptions of such attrition in their districts. Findings indicate that community members perceived high turnover as negative and believed that turnover was created by financial pressures, rural community resistance to educational trends, and bias against…

High School Band Students' Perspectives of Teacher Turnover

ERIC Educational Resources Information Center

Kloss, Thomas E.

2013-01-01

Teacher turnover remains an important issue in education. The least researched perspectives, though, are those of the students who experience teacher turnover. The purpose of this study was to examine how high school band students experience teacher turnover. A total of twelve students were interviewed, representing three schools that experienced…

Homogenous Electrocatalytic Oxygen Reduction Rates Correlate with Reaction Overpotential in Acidic Organic Solutions

PubMed Central

2016-01-01

Improved electrocatalysts for the oxygen reduction reaction (ORR) are critical for the advancement of fuel cell technologies. Herein, we report a series of 11 soluble iron porphyrin ORR electrocatalysts that possess turnover frequencies (TOFs) from 3 s–1 to an unprecedented value of 2.2 × 106 s–1. These TOFs correlate with the ORR overpotential, which can be modulated by changing the E1/2 of the catalyst using different ancillary ligands, by changing the solvent and solution acidity, and by changing the catalyst’s protonation state. The overpotential is well-defined for these homogeneous electrocatalysts by the E1/2 of the catalyst and the proton activity of the solution. This is the first such correlation for homogeneous ORR electrocatalysis, and it demonstrates that the remarkably fast TOFs are a consequence of high overpotential. The correlation with overpotential is surprising since the turnover limiting steps involve oxygen binding and protonation, as opposed to turnover limiting electron transfer commonly found in Tafel analysis of heterogeneous ORR materials. Computational studies show that the free energies for oxygen binding to the catalyst and for protonation of the superoxide complex are in general linearly related to the catalyst E1/2, and that this is the origin of the overpotential correlations. This analysis thus provides detailed understanding of the ORR barriers. The best catalysts involve partial decoupling of the influence of the second coordination sphere from the properties of the metal center, which is suggested as new molecular design strategy to avoid the limitations of the traditional scaling relationships for these catalysts. PMID:27924314

High-resolution observations of low-luminosity gigahertz-peaked spectrum and compact steep-spectrum sources

NASA Astrophysics Data System (ADS)

Collier, J. D.; Tingay, S. J.; Callingham, J. R.; Norris, R. P.; Filipović, M. D.; Galvin, T. J.; Huynh, M. T.; Intema, H. T.; Marvil, J.; O'Brien, A. N.; Roper, Q.; Sirothia, S.; Tothill, N. F. H.; Bell, M. E.; For, B.-Q.; Gaensler, B. M.; Hancock, P. J.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kapińska, A. D.; Lenc, E.; Morgan, J.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q.; Heywood, I.; Popping, A.

2018-06-01

We present very long baseline interferometry observations of a faint and low-luminosity (L1.4 GHz < 1027 W Hz-1) gigahertz-peaked spectrum (GPS) and compact steep-spectrum (CSS) sample. We select eight sources from deep radio observations that have radio spectra characteristic of a GPS or CSS source and an angular size of θ ≲ 2 arcsec, and detect six of them with the Australian Long Baseline Array. We determine their linear sizes, and model their radio spectra using synchrotron self-absorption (SSA) and free-free absorption (FFA) models. We derive statistical model ages, based on a fitted scaling relation, and spectral ages, based on the radio spectrum, which are generally consistent with the hypothesis that GPS and CSS sources are young and evolving. We resolve the morphology of one CSS source with a radio luminosity of 10^{25} W Hz^{-1}, and find what appear to be two hotspots spanning 1.7 kpc. We find that our sources follow the turnover-linear size relation, and that both homogeneous SSA and an inhomogeneous FFA model can account for the spectra with observable turnovers. All but one of the FFA models do not require a spectral break to account for the radio spectrum, while all but one of the alternative SSA and power-law models do require a spectral break to account for the radio spectrum. We conclude that our low-luminosity sample is similar to brighter samples in terms of their spectral shape, turnover frequencies, linear sizes, and ages, but cannot test for a difference in morphology.

Regional processes in mangrove ecosystems: Spatial scaling relationships, biomass, and turnover rates following catastrophic disturbance

USGS Publications Warehouse

Ward, G.A.; Smith, T. J.; Whelan, K.R.T.; Doyle, T.W.

2006-01-01

Physiological processes and local-scale structural dynamics of mangroves are relatively well studied. Regional-scale processes, however, are not as well understood. Here we provide long-term data on trends in structure and forest turnover at a large scale, following hurricane damage in mangrove ecosystems of South Florida, U.S.A. Twelve mangrove vegetation plots were monitored at periodic intervals, between October 1992 and March 2005. Mangrove forests of this region are defined by a -1.5 scaling relationship between mean stem diameter and stem density, mirroring self-thinning theory for mono-specific stands. This relationship is reflected in tree size frequency scaling exponents which, through time, have exhibited trends toward a community average that is indicative of full spatial resource utilization. These trends, together with an asymptotic standing biomass accumulation, indicate that coastal mangrove ecosystems do adhere to size-structured organizing principles as described for upland tree communities. Regenerative dynamics are different between areas inside and outside of the primary wind-path of Hurricane Andrew which occurred in 1992. Forest dynamic turnover rates, however, are steady through time. This suggests that ecological, more-so than structural factors, control forest productivity. In agreement, the relative mean rate of biomass growth exhibits an inverse relationship with the seasonal range of porewater salinities. The ecosystem average in forest scaling relationships may provide a useful investigative tool of mangrove community biomass relationships, as well as offer a robust indicator of general ecosystem health for use in mangrove forest ecosystem management and restoration. ?? Springer 2006.

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

PubMed Central

Calado, António José; Moita, Maria Teresa; Cunha, Marina R.

2017-01-01

From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceanographic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer- (inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change. PMID:28472179

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period.

PubMed

Vidal, Tânia; Calado, António José; Moita, Maria Teresa; Cunha, Marina R

2017-01-01

From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceanographic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer- (inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change.

Does drought legacy alter the recovery of grassland carbon dynamics from drought?

NASA Astrophysics Data System (ADS)

Bahn, M.; Hasibeder, R.; Fuchslueger, L.; Ingrisch, J.; Ladreiter-Knauss, T.; Lair, G.; Reinthaler, D.; Richter, A.; Kaufmann, R.

2016-12-01

Climate projections suggest an increase in the frequency and the severity of extreme climatic events, such as droughts, with consequences for the carbon cycle and its feedbacks to the climate system. An important implication of increasing drought frequency is that possible legacies of previous droughts may increasingly affect ecosystem responses to new drought events, though this has been rarely tested. Based on a series of severe experimental droughts performed during nine subsequent years on a mountain grassland in the Austrian Alps, we present evidence of effects of drought legacies on the recovery of grassland carbon dynamics from drought and analyse the underlying mechanisms. Both single and recurrent droughts led to increased aboveground productivity during drought recovery relative to control plots, favoring the biomass production and leaf area of grass species more strongly than of forbs. Belowground productivity was significantly increased during recovery. This led to higher total root length, even though specific root length was strongly reduced during recovery, particularly after recurrent drought events. Following rewetting, the temperature dependence of soil respiration was increasingly diminished and the Birch effect declined with progressive recurrence of droughts. This was paralleled by a change in soil aggregate stability and soil porosity in plots repeatedly exposed to drought. Pulse-labelling experiments revealed effects of drought legacy on plant carbon uptake and belowground allocation and altered microbial turnover of recent plant-derived carbon during and after a subsequent drought. Shifts in tissue nitrogen concentration indicate that drought effects on soil nitrogen turnover and availability could play an important role in the recovery of grassland carbon dynamics following both single and recurrent droughts. In conclusion, drought legacies can alter the recovery of grassland carbon dynamics from drought, the effects increasing with increasing drought frequency and involving changes in both plant functional composition and soil structure and processes.

Does drought legacy alter the recovery of grassland carbon dynamics from drought?

NASA Astrophysics Data System (ADS)

Bahn, Michael; Hasibeder, Roland; Fuchslueger, Lucia; Ingrisch, Johannes; Ladreiter-Knauss, Thomas; Lair, Georg; Reinthaler, David; Richter, Andreas; Kaufmann, Rüdiger

2017-04-01

Climate projections suggest an increase in the frequency and the severity of extreme climatic events, such as droughts, with consequences for the carbon cycle and its feedbacks to the climate system. An important implication of increasing drought frequency is that possible legacies of previous droughts may increasingly affect ecosystem responses to new drought events, though this has been rarely tested. Based on a series of severe experimental droughts performed during nine subsequent years on a mountain grassland in the Austrian Alps, we present evidence of effects of drought legacies on the recovery of grassland carbon dynamics from drought and analyse the underlying mechanisms. Both single and recurrent droughts led to increased aboveground productivity during drought recovery relative to control plots, favoring the biomass production and leaf area of grass species more strongly than of forbs. Belowground productivity was significantly increased during recovery. This led to higher total root length, even though specific root length was strongly reduced during recovery, particularly after recurrent drought events. Following rewetting, the temperature dependence of soil respiration was increasingly diminished and the Birch effect declined with progressive recurrence of droughts. This was paralleled by a change in soil aggregate stability and soil porosity in plots repeatedly exposed to drought. Isotopic pulse-labelling experiments revealed effects of drought legacy on plant carbon uptake and belowground allocation and altered microbial turnover of recent plant-derived carbon during and after a subsequent drought. Shifts in tissue nitrogen concentration indicate that drought effects on soil nitrogen turnover and availability could play an important role in the recovery of grassland carbon dynamics following both single and recurrent droughts. In conclusion, drought legacies can alter the recovery of grassland carbon dynamics from drought, the effects increasing with increasing drought frequency and involving changes in both plant functional composition and soil structure and processes.

Job satisfaction mediates subjective social status and turnover intention among Chinese nurses.

PubMed

Feng, Danjun; Su, Shan; Yang, Yang; Xia, Jinghua; Su, Yonggang

2017-09-01

Nurse turnover is one of the reasons for the global nurse shortage. Although previous studies have examined the determinants of turnover intention in detail, there is limited knowledge on the effect of subjective social status on nurse turnover intention. Therefore, in this study, we examined this relationship, including job satisfaction as a mediator, among Chinese nurses. This cross-sectional study employed questionnaires to assess subjective social status, job satisfaction, and turnover intention in 581 nurses who were randomly recruited from 10 hospitals in Jinan, China. The results partially supported our model. Although subjective social status exerted no significant direct effect on turnover intention, it exerted a significant indirect effect through job satisfaction. These results provide a new insight into why nurses leave their jobs, and possible new solutions to the nurse turnover problem. Efforts should be made to improve nurses' subjective social status. © 2017 John Wiley & Sons Australia, Ltd.

Characteristics of the Nursing Practice Environment Associated With Lower Unit-Level RN Turnover.

PubMed

Nelson-Brantley, Heather V; Park, Shin Hye; Bergquist-Beringer, Sandra

2018-01-01

The aim of this study is to examine characteristics of the nursing practice environment associated with lower RN turnover. Identifying characteristics of the practice environment that contribute to lower RN turnover is important for meeting the national quality strategy priority of reducing healthcare costs. Data from 1002 adult care units in 162 National Database of Nursing Quality Indicators participating hospitals were analyzed using multivariate linear regression. The Practice Environment Scale of the Nursing Work Index was used to measure practice environment characteristics. RN turnover was measured at the unit level. Nursing units with higher overall ratings of the nursing practice environment had lower rates of RN turnover. Units with higher RN perceived staffing and resource adequacy experienced significantly lower RN turnover. Unit managers and hospital administrators should consider RN perception of staffing and resource adequacy and the overall practice environment when developing targeted strategies for decreasing RN turnover.

The implications of linking the dynamic performance and turnover literatures.

PubMed

Sturman, M C; Trevor, C O

2001-08-01

This article examines how the literatures of dynamic performance and the performance-turnover relationship inform each other. The nonrandom performance turnover relationship suggests that dynamic performance studies may be biased by their elimination of participants who do not remain for the entire study period. The authors demonstrated that the performance slopes of those who leave an organization differ from the performance slopes of those who remain. This finding suggests that studies of the performance-turnover relationship need to consider employee performance trends when predicting turnover. Replicating and extending the research of D. A. Harrison, M. Virick, and S. William (1996), the authors found that performance changes from the previous month and performance trends measured over a longer time period explained variance in voluntary turnover beyond current performance. Finally, the authors showed that performance trends interacted with current performance in the prediction of voluntary turnover.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nganga, John K.; Samanamu, Christian R.; Tanski, Joseph M.

In a series of rhenium tricarbonyl complexes coordinated by asymmetric diimine ligands containing a pyridine moiety bound to an oxazoline ring were synthesized, structurally and electrochemically characterized, and screened for CO 2 reduction ability. We reported complexes are of the type Re(N-N)(CO) 3Cl, with N-N = 2-(pyridin-2-yl)-4,5-dihydrooxazole (1), 5-methyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (2), and 5-phenyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (3). The electrocatalytic reduction of CO 2 by these complexes was observed in a variety of solvents and proceeds more quickly in acetonitrile than in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The analysis of the catalytic cycle for electrochemical CO 2 reduction by 1 in acetonitrile using densitymore » functional theory (DFT) supports the C–O bond cleavage step being the rate-determining step (RDS) (ΔG ‡ = 27.2 kcal mol –1). Furthermore, the dependency of the turnover frequencies (TOFs) on the donor number (DN) of the solvent also supports that C–O bond cleavage is the rate-determining step. Moreover, the calculations using explicit solvent molecules indicate that the solvent dependence likely arises from a protonation-first mechanism. Unlike other complexes derived from fac-Re(bpy)(CO) 3Cl (I; bpy = 2,2'-bipyridine), in which one of the pyridyl moieties in the bpy ligand is replaced by another imine, no catalytic enhancement occurs during the first reduction potential. Remarkably, catalysts 1 and 2 display relative turnover frequencies, (i cat/i p) 2, up to 7 times larger than that of I.« less

Integrating Turnover Reasons and Shocks with Turnover Decision Processes

ERIC Educational Resources Information Center

Maertz, Carl P., Jr.; Kmitta, Kayla R.

2012-01-01

We interviewed and classified 186 quitters from many jobs and organizations via a theoretically-based protocol into five decision process types. We then tested exploratory hypotheses comparing users of these types on their propensity to report certain turnover reasons and turnover shocks. "Impulsive-type quitters," with neither a job offer in hand…

Diagnosing Causes of Teacher Retention, Mobility and Turnover: Guidelines for TIF Grantees

ERIC Educational Resources Information Center

Finster, Matthew

2015-01-01

To effectively address teacher turnover, Teacher Incentive Fund (TIF) grantees need to follow an approach that entails aligning the tracking, diagnosing, and intervening processes. Unfortunately, too often retention strategies are implemented without regard to the various types of teacher turnover and specific data about the causes of turnover.…

How Teacher Turnover Harms Student Achievement

ERIC Educational Resources Information Center

Ronfeldt, Matthew; Loeb, Susanna; Wyckoff, James

2013-01-01

Researchers and policymakers often assume that teacher turnover harms student achievement, though recent studies suggest this may not be the case. Using a unique identification strategy that employs school-by-grade level turnover and two classes of fixed-effects models, this study estimates the effects of teacher turnover on over 850,000 New York…

Investing in Leadership: The District's Role in Managing Principal Turnover

ERIC Educational Resources Information Center

Mascall, Blair; Leithwood, Kenneth

2010-01-01

This article presents the results of research into the impact of principal turnover on schools, and the ability of schools to mitigate the negative effects of frequent turnover by distributing leadership in the schools. The findings from this qualitative and quantitative analysis show that rapid principal turnover does indeed have a negative…

Superintendent Turnover in Kentucky. Summary. Issues & Answers. REL 2011-No. 113

ERIC Educational Resources Information Center

Johnson, Jerry; Huffman, Tyler; Madden, Karen; Shope, Shane

2011-01-01

This study examines superintendent turnover in Kentucky public school districts for 1998/99-2007/08, looking at how turnover varies by rural status, Appalachian and non-Appalachian region, and 2007/08 school district characteristics. Key findings include: (1) Kentucky school districts averaged one superintendent turnover during 1998/99-2007/08;…

Superintendent Turnover in Kentucky. Issues & Answers. REL 2011-No. 113

ERIC Educational Resources Information Center

Johnson, Jerry; Huffman, Tyler; Madden, Karen; Shope, Shane

2011-01-01

This study examines superintendent turnover in Kentucky public school districts for 1998/99-2007/08, looking at how turnover varies by rural status, Appalachian and non-Appalachian region, and 2007/08 school district characteristics. Key findings include: (1) Kentucky school districts averaged one superintendent turnover during 1998/99-2007/08;…

A Review of the Literature on Administrator Turnover: Why They Move on or Are Displaced.

ERIC Educational Resources Information Center

Shields, Bruce A.

Employee turnover contributes to lost production, disrupts normal business practices, and is expensive. This literature review examines turnover of three administrator positions: the school superintendent, the executive director of nonprofit agencies, and the chief executive officer of for-profit corporations. The most cited reason for turnover of…

Salary and Ranking and Teacher Turnover: A Statewide Study

ERIC Educational Resources Information Center

Garcia, Cynthia Martinez; Slate, John R.; Delgado, Carmen Tejeda

2009-01-01

This study examined three years of data obtained from the Academic Excellence Indicator System of the State of Texas regarding teacher turnover rate and teacher salary. Across all public school districts, teacher salary was consistently negatively related to teacher turnover; that is, where salary was lower, turnover rate was higher When data were…

Effects of role stress on nurses' turnover intentions: The mediating effects of organizational commitment and burnout.

PubMed

Han, Sang-Sook; Han, Jeong-Won; An, Young-Suk; Lim, So-Hee

2015-10-01

This paper was designed to extend the extant research regarding factors related to nurses' turnover intentions. This survey-based study was based on a path analysis designed to verify a hypothesized causal model involving nurses' role stress, organizational commitment, turnover intentions, and burnout. This study distributed 500 questionnaires to nurses in general hospitals with more than 500 beds located in Seoul, Korea, during 16-30 April 2012. Role conflict, an underlying factor in role stress, had no significant effect on role stress, but the results showed that role ambiguity reduced organizational commitment. On the other hand, role conflict and role ambiguity increased the level of burnout. Organizational commitment reduced turnover intentions, and burnout increased turnover intentions. Role conflict and role ambiguity had no direct effect on turnover intentions, but they had indirect effects on organizational commitment and burnout. To reduce nurses' turnover rate, this study recommends developing plans to improve their organizational commitment because it mediates role stress and turnover intention. © 2014 The Authors. Japan Journal of Nursing Science © 2014 Japan Academy of Nursing Science.

The mediating effect of emotional intelligence between emotional labour, job stress, burnout and nurses' turnover intention.

PubMed

Hong, Eunyoung; Lee, Young Sook

2016-12-01

This study was designed to construct and test the structural equation modelling on nurses' turnover intention including emotional labour, job stress, emotional intelligence and burnout in order to identify the mediating effect of emotional intelligence between those variables. Emotional labour, job stress and burnout increase turnover intention of nurses. However, emotional intelligence is negatively correlated with emotional labour and reduces job stress, burnout and turnover intention. Structural equation modelling was used to analyse the goodness of fit of the hypothetical model of nurses' turnover intention. Research data were collected via questionnaires from 4 to 22 August 2014 and analysed using SPSS version 18.0 and AMOS version 20.0. The model fit indices for the hypothetical model were suitable for recommended. Emotional intelligence has decreasing effect on turnover intention through burnout, although its direct effect on turnover intention is not significant. Emotional intelligence has mediation effect between emotional labour and burnout. This study's results suggest that increasing emotional intelligence might critically decrease nurses' turnover intention by reducing the effect of emotional labour on burnout. © 2016 John Wiley & Sons Australia, Ltd.

Clinical supervision, emotional exhaustion, and turnover intention: A study of substance abuse treatment counselors in NIDA’s Clinical Trials Network

PubMed Central

Knudsen, Hannah K.; Ducharme, Lori J.; Roman, Paul M

2008-01-01

An intriguing hypothesis is that clinical supervision may protect against counselor turnover. This idea has been mentioned in recent discussions of the substance abuse treatment workforce. To test this hypothesis, we extend our previous research on emotional exhaustion and turnover intention among counselors by estimating the associations between clinical supervision and these variables in a large sample (n = 823). An exploratory analysis reveals that clinical supervision was negatively associated with emotional exhaustion and turnover intention. Given our previous findings that emotional exhaustion and turnover intention were associated with job autonomy, procedural justice, and distributive justice, we estimate a structural equation model to examine whether these variables mediated clinical supervision’s associations with emotional exhaustion and turnover intention. These data support the fully mediated model. We found the perceived quality of clinical supervision is strongly associated with counselors’ perceptions of job autonomy, procedural justice, and distributive justice, which are, in turn, associated with emotional exhaustion and turnover intention. These data offer support for the protective role of clinical supervision in substance abuse treatment counselors’ turnover and occupational wellbeing. PMID:18424048

Beyond the tradition: test of an integrative conceptual model on nurse turnover.

PubMed

Battistelli, A; Portoghese, I; Galletta, M; Pohl, S

2013-03-01

This paper aimed to extend research on nurse turnover by developing and testing a theoretical model of turnover intention that includes two emergent key off-the-job constructs, work-family conflict (WFC) and community embeddedness (CE). Nurse turnover is considered one of the most significant issues in health care. There is a considerable body of knowledge that has focused on the study of the on-the-job factors of nurse turnover, showing the important role of job attitudes. Recently, WFC and job embeddedness (JE) have been identified as variables that could help explain levels of nurse turnover. Using structural equation modelling from a cross-sectional survey, the relationships between the variables were explored in a sample of 440 nurses from an Italian public hospital. The questionnaire measures demographic data and psychosocial factors such as job satisfaction, organizational commitment, WFC, CE and turnover intentions. The findings supported the importance of non-work dimensions in turnover models. The results suggest that when studying turnover phenomena in health organizations, the extra-work domains (WFC and JE) can contribute to a decrease in the intention to leave, in addition to the more typically emphasized attitude dimension. © 2012 The Authors. International Nursing Review © 2012 International Council of Nurses.

The mediating effects of job satisfaction on turnover intention for long-term care nurses in Taiwan.

PubMed

Kuo, Huai-Ting; Lin, Kuan-Chia; Li, I-Chuan

2014-03-01

This study explores the mediating effects of job satisfaction on work stress and turnover intention among long-term care nurses in Taiwan. Healthcare institutions face a nursing shortage, and it is important to examine the factors that influence turnover intention among nurses. Excessive levels of work stress may lead to employee dissatisfaction and a significant inverse relationship between work stress and job satisfaction, including subsequent effects on turnover among nurses. However, little is known about the mediating role of job satisfaction on work stress and turnover intention among long-term care nurses. A cross-sectional survey and a correlation design were used. Multistage linear regression was used to test the mediation model. This study showed that job satisfaction significantly mediated the relationship between work stress and turnover intention. Thirty-eight percent of the variance in turnover intention explained by work stress was accounted for by the mediation pathway. The results of this study showed that higher job satisfaction significantly decreased work stress and turnover intention among long-term care nurses. This study provides nursing administrators with a resource to build a supportive environment to increase nurses' job satisfaction and to decrease their stress and turnover. © 2013 John Wiley & Sons Ltd.

Comparative Proteome Analysis of hAT-MSCs Isolated from Chronic Renal Failure Patients with Differences in Their Bone Turnover Status.

PubMed

Kasap, Murat; Yeğenağa, Itır; Akpinar, Gurler; Tuncay, Mehmet; Aksoy, Ayça; Karaoz, Erdal

2015-01-01

The relationship between the stem cells and the bone turnover in uremic bone disease due to chronic renal failure (CRF) is not described. The aim of this study was to investigate the effect of bone turnover status on stem cell properties. To search for the presence of such link and shed some light on stem-cell relevant mechanisms of bone turnover, we carried out a study with mesenchymal stem cells. Tissue biopsies were taken from the abdominal subcutaneous adipose tissue of a CRF patient with secondary hyperparathyroidism with the high turnover bone disease. This patient underwent parathyroidectomy operation (PTX) and another sample was taken from this patient after PTX. A CRF patient with adynamic bone disease with low turnover and a healthy control were also included. Mesenchymal stem cells isolated from the subjects were analyzed using proteomic and molecular approaches. Except ALP activity, the bone turnover status did not affect common stem cell properties. However, detailed proteome analysis revealed the presence of regulated protein spots. A total of 32 protein spots were identified following 2D gel electrophoresis and MALDI-TOF/TOF analyzes. The identified proteins were classified into seven distinct groups and their potential relationship to bone turnover were discussed. Distinct protein expression patterns emerged in relation to the bone turnover status indicate a possible link between the stem cells and bone turnover in uremic bone disease due to CRF.

The addition of a regional block team to the orthopedic operating rooms does not improve anesthesia-controlled times and turnover time in the setting of long turnover times.

PubMed

Eappen, Sunil; Flanagan, Hugh; Lithman, Rachel; Bhattacharyya, Neil

2007-03-01

To determine whether a regional block team with a dedicated space for performance of regional anesthetics would decrease turnover time and shorten the working day in a busy orthopedic practice with lengthy turnover times. Prospective, randomized study. Tertiary-care teaching hospital. 927 orthopedic procedures over a three-month period. The randomized placement of a regional block team to the orthopedic operating room (OR) suite. We evaluated the differences in anesthesia-controlled times, first-case start times, turnover times, and OR end times using a computerized OR information system. We also surveyed the surgeons regarding their perceptions of changes in turnover time and anesthesia-controlled times during the study period. Standard descriptive statistics were computed. Of a total of 927 cases, 398 cases were cared for by a regional block team and 529 cases received care in the usual manner, with the OR team providing the regional block. There was no difference between the study and control groups for on-time, first-case starts (57.73% vs 42.27%), induction time (13.2 vs 14.2 min), emergence time (8.1 vs 9.0 min), turnover time (70.3 vs 77.8 min), and OR end times. Most of the surgeons surveyed felt that the regional block team reduced turnover time significantly. A regional block team in this environment does not reduce anesthesia-controlled times and turnover times in an orthopedic OR suite with long turnover times, and it would be virtually impossible to recover the associated extra cost. The surgeons' perspective of turnover time is inaccurate.

Reducing Operating Room Turnover Time for Robotic Surgery Using a Motor Racing Pit Stop Model.

PubMed

Souders, Colby P; Catchpole, Ken R; Wood, Lauren N; Solnik, Jonathon M; Avenido, Raymund M; Strauss, Paul L; Eilber, Karyn S; Anger, Jennifer T

2017-08-01

Operating room (OR) turnover time, time taken between one patient leaving the OR and the next entering, is an important determinant of OR utilization, a key value metric for hospital administrators. Surgical robots have increased the complexity and number of tasks required during an OR turnover, resulting in highly variable OR turnover times. We sought to streamline the turnover process and decrease robotic OR turnover times and increase efficiency. Direct observation of 45 pre-intervention robotic OR turnovers was performed. Following a previously successful model for handoffs, we employed concepts from motor racing pit stops, including briefings, leadership, role definition, task allocation and task sequencing. Turnover task cards for staff were developed, and card assignments were distributed for each turnover. Forty-one cases were observed post-intervention. Average total OR turnover time was 99.2 min (95% CI 88.0-110.3) pre-intervention and 53.2 min (95% CI 48.0-58.5) at 3 months post-intervention. Average room ready time from when the patient exited the OR until the surgical technician was ready to receive the next patient was 42.2 min (95% CI 36.7-47.7) before the intervention, which reduced to 27.2 min at 3 months (95% CI 24.7-29.7) post-intervention (p < 0.0001). Role definition, task allocation and sequencing, combined with a visual cue for ease-of-use, create efficient, and sustainable approaches to decreasing robotic OR turnover times. Broader system changes are needed to capitalize on that result. Pit stop and other high-risk industry models may inform approaches to the management of tasks and teams.

Reducing turnover is not enough: The need for proficient organizational cultures to support positive youth outcomes in child welfare

PubMed Central

Glisson, Charles

2013-01-01

Objective High caseworker turnover has been identified as a factor in the poor outcomes of child welfare services. However, almost no empirical research has examined the relationship between caseworker turnover and youth outcomes in child welfare systems and there is an important knowledge gap regarding whether, and how, caseworker turnover relates to outcomes for youth. We hypothesized that the effects of caseworker turnover are moderated by organizational culture such that reduced caseworker turnover is only associated with improved youth outcomes in organizations with proficient cultures. Methods The study applied hierarchical linear models (HLM) analysis to the second National Survey of Child and Adolescent Well-being (NSCAW II) with a U.S. nationwide sample of 2,346 youth aged 1.5- to 18-years-old and 1,544 caseworkers in 73 child welfare agencies. Proficient organizational culture was measured by caseworkers’ responses to the Organizational Social Context (OSC) measure; staff turnover was reported by the agencies’ directors; and youth outcomes were measured as total problems in psychosocial functioning with the Child Behavior Checklist (CBCL) completed by the youths’ caregivers at intake and at 18 month follow-up. Results The association between caseworker turnover and youth outcomes was moderated by organizational culture. Youth outcomes were improved with lower staff turnover in proficient organizational cultures and the best outcomes occurred in organizations with low turnover and high proficiency. Conclusions To be successful, efforts to improve child welfare services by lowering staff turnover must also create proficient cultures that expect caseworkers to be competent and responsive to the needs of the youth and families they serve. PMID:24273363

Nursing staff turnover at a Swedish university hospital: an exploratory study.

PubMed

Sellgren, Stina F; Kajermo, Kerstin N; Ekvall, Göran; Tomson, Göran

2009-11-01

The aim was to explore opinions on individual needs and other factors that may influence nursing staff turnover. High staff turnover is a great problem for many hospitals. It is shown to have a negative effect on the quality of nursing care and to increase hospital costs. In 2004 in a large university hospital in Sweden five focus group discussions (FGDs) including department heads (1), nursing managers (2) and members of nursing staff (2) were carried out. The questions to be addressed were 'Why do nurses leave?' and 'Why do nurses stay?' In addition, register data of staff turnover for 2002-2003 were analysed in relation to different facts about the units, such as number of employees, type of care and medical specialty. Categories of opinions identified in the FGDs were compared with results of the statistical analyses on the relationship between staff turnover and unit parameters to identify overall factors that may influence on nurse staff turnover. Four major factors were identified as having a possible influence on staff turnover: 'intrinsic values of motivation', 'work load', 'unit size 'and 'leadership'. Smaller units had lower staff turnover as well as outpatient units and day care. It was not possible to compare statements from participants from smaller units with those from participants from larger units. Two factors had diverging data, 'salary' and 'spirit of the time'. A surprising finding was the little mention of patient care in relation to staff turnover. It is important for managers to ensure that intrinsic values of nurses are met to minimise the risk for high turnover rates. Inpatient care must receive adequate staffing and nursing care could be organised into smaller units or work teams to avoid dissatisfaction and high turnover.

Soil and vegetation carbon turnover times across forest biomes in eastern China

NASA Astrophysics Data System (ADS)

Wang, Jingsong; Niu, Shuli

2017-04-01

1. Resent studies reveal that terrestrial biosphere is now a net carbon (C) sink for atmospheric C dixoide (CO2), however, whether this C sink can persist with climate change is still uncertain. Such uncertainty comes not only from C input, but also largely from C turnover times in an ecosystem. Knowledge of C turnover times is critical for modelling C cycle and evaluating C sink potential. Our current understanding of how long C can be stored in soils and vegetation and what are their controlling factors are still poorly understood. 2. We used C stocks from 1087 plots in soils and 2753 plots in vegetation and investigated the spatial patterns and controlling factors of C turnover times across the forest transect in the eastern China. 3. Our results showed a clear latitudinal pattern of C turnover times, with the lowest turnover times in the low-latitude zones and highest values in the high-latitude. Mean annual temperature (MAT) and mean annual precipitation (MAP) were the most important controlling factors on the soil C turnover times while forest age accounted for the most majority of variations in the vegetation C turnover times. Our findings also indicated that forest origin (planted forest, natural forest) was also responsible for the variations of vegetation C turnover times while forest type and soil properties were not the dominant controlling factors. 4. Our study highlights different dominant controlling factors on the soils and vegetation C turnover times and different mechanisms underlying above- and below-ground C turnover. The findings can help to better understand and reduce the large uncertainty in predictive models of the coupled carbon-climate system.

Plasma Protein Turnover Rates in Rats Using Stable Isotope Labeling, Global Proteomics, and Activity-Based Protein Profiling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jordan Ned; Tyrrell, Kimberly J.; Hansen, Joshua R.

Protein turnover is important for general health on cellular and organism scales providing a strategy to replace old, damaged, or dysfunctional proteins. Protein turnover also informs of biomarker kinetics, as a better understanding of synthesis and degradation of proteins increases the clinical utility of biomarkers. Here, turnover rates of plasma proteins in rats were measured in vivo using a pulse-chase stable isotope labeling experiment. During the pulse, rats (n=5) were fed 13C6-labeled lysine (“heavy”) feed for 23 days to label proteins. During the chase, feed was changed to an unlabeled equivalent feed (“light”), and blood was repeatedly sampled from ratsmore » over 10 time points for 28 days. Plasma samples were digested with trypsin, and analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). MaxQuant was used to identify peptides and proteins, and quantify heavy:light lysine ratios. A system of ordinary differential equations was used to calculate protein turnover rates. Using this approach, 273 proteins were identified, and turnover rates were quantified for 157 plasma proteins with half-lives ranging 0.3-103 days. For the ~70 most abundant proteins, variability in turnover rates among rats was low (median coefficient of variation: 0.09). Activity-based protein profiling was applied to pooled plasma samples to enrich serine hydrolases using a fluorophosphonate (FP2) activity-based probe. This enrichment resulted in turnover rates for an additional 17 proteins. This study is the first to measure global plasma protein turnover rates in rats in vivo, measure variability of protein turnover rates in any animal model, and utilize activity-based protein profiling for enhancing measurements of targeted, low-abundant proteins, such as those commonly used as biomarkers. Measured protein turnover rates will be important for understanding of the role of protein turnover in cellular and organism health as well as increasing the utility of protein biomarkers through better understanding of processes governing biomarker kinetics.« less

Workplace violence, job satisfaction, burnout, perceived organisational support and their effects on turnover intention among Chinese nurses in tertiary hospitals: a cross-sectional study.

PubMed

Liu, Wenhui; Zhao, Shihong; Shi, Lei; Zhang, Zhong; Liu, Xinyan; Li, Li; Duan, Xiaojian; Li, Guoqiang; Lou, Fengge; Jia, Xiaoli; Fan, Lihua; Sun, Tao; Ni, Xin

2018-06-09

Our aims were to assess the relationship between workplace violence, job satisfaction, burnout, organisational support and turnover intention, and to explore factors associated with turnover intention among nurses in Chinese tertiary hospitals. The purposive sampling method was used to collect data from August 2016 through January 2017. A total of 1761 nurses from 9 public tertiary hospitals in 4 provinces (municipalities) located in eastern (Beijing), central (Heilongjiang, Anhui) and western (Shaanxi) regions of China completed the questionnaires (effective response rate=85.20%). A cross-sectional study was conducted using the Workplace Violence Scale, Chinese Maslach Burnout Inventory General Survey, Minnesota Job Satisfaction Questionnaire Revised Short Version, Perceived Organizational Support-Simplified Version Scale and Turnover Intention Scale. A total of 1216 of 1706 (69.1%) participants had high turnover intention. During the previous 12 months, the prevalence of physical violence and psychological violence towards nurses was 9.60% and 59.64%, respectively. As expected, the level of turnover intention was negatively correlated with participants' scores on job satisfaction (r=-0.367, p<0.001) and perceived organisational support (r=-0.379, p<0.001), respectively. Burnout was positively associated with turnover intention (r=0.444, p<0.001). Workplace violence was positively associated with turnover intention (β=0.035, p<0.001) in linear regression analysis. The total effect (β=0.53) of workplace violence on turnover intention comprised its direct effect (β=0.36) and its indirect effect (β=0.17). Perceived organisational support served as a mediator between workplace violence, job satisfaction, burnout and turnover intention, and it had a significantly negative impact on turnover intention. Therefore, nursing managers should understand the importance of the organisation's support and establish a reasonable incentive system to decrease turnover intention. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Workplace violence, job satisfaction, burnout, perceived organisational support and their effects on turnover intention among Chinese nurses in tertiary hospitals: a cross-sectional study

PubMed Central

Zhang, Zhong; Liu, Xinyan; Li, Li; Duan, Xiaojian; Li, Guoqiang; Lou, Fengge; Jia, Xiaoli; Fan, Lihua; Sun, Tao; Ni, Xin

2018-01-01

Objectives Our aims were to assess the relationship between workplace violence, job satisfaction, burnout, organisational support and turnover intention, and to explore factors associated with turnover intention among nurses in Chinese tertiary hospitals. Methods The purposive sampling method was used to collect data from August 2016 through January 2017. A total of 1761 nurses from 9 public tertiary hospitals in 4 provinces (municipalities) located in eastern (Beijing), central (Heilongjiang, Anhui) and western (Shaanxi) regions of China completed the questionnaires (effective response rate=85.20%). A cross-sectional study was conducted using the Workplace Violence Scale, Chinese Maslach Burnout Inventory General Survey, Minnesota Job Satisfaction Questionnaire Revised Short Version, Perceived Organizational Support-Simplified Version Scale and Turnover Intention Scale. Results A total of 1216 of 1706 (69.1%) participants had high turnover intention. During the previous 12 months, the prevalence of physical violence and psychological violence towards nurses was 9.60% and 59.64%, respectively. As expected, the level of turnover intention was negatively correlated with participants’ scores on job satisfaction (r=−0.367, p<0.001) and perceived organisational support (r=−0.379, p<0.001), respectively. Burnout was positively associated with turnover intention (r=0.444, p<0.001). Workplace violence was positively associated with turnover intention (β=0.035, p<0.001) in linear regression analysis. The total effect (β=0.53) of workplace violence on turnover intention comprised its direct effect (β=0.36) and its indirect effect (β=0.17). Conclusions Perceived organisational support served as a mediator between workplace violence, job satisfaction, burnout and turnover intention, and it had a significantly negative impact on turnover intention. Therefore, nursing managers should understand the importance of the organisation’s support and establish a reasonable incentive system to decrease turnover intention. PMID:29886440

Loss of job-related right to healthcare associated with employment turnover: challenges for the Mexican health system.

PubMed

Guerra, Germán; Gutiérrez-Calderón, Emilio; Salgado de Snyder, Nelly; Borja-Aburto, Víctor Hugo; Martínez-Valle, Adolfo; González-Block, Miguel Ángel

2018-06-15

The Mexican health system segments access and right to healthcare according to worker position in the labour market. In this contribution we analyse how access and continuity of healthcare gets interrupted by employment turnover in the labour market, including its formal and informal sectors, as experienced by affiliates to the Mexican Institute of Social Security (IMSS) at national level, and of workers with type 2 diabetes (T2DM) in Mexico City. Using data from the National Employment and Occupation Survey, 2014, and from IMSS electronic medical records for workers in Mexico City, we estimated annual employment turnover rates to measure the loss of healthcare access due to labour market dynamics. We fitted a binary logistic regression model to analyse the association between sociodemographic variables and employment turnover. Lastly we analysed job-related access to health care in relation to employment turnover events. At national level, 38.3% of IMSS affiliates experienced employment turnover at least once, thus losing the right to access to healthcare. The turnover rate for T2DM patients was 22.5%. Employment turnover was more frequent at ages 20-39 (38.6% national level; 28% T2DM) and among the elderly (62.4% national level; 26% T2DM). At the national level, higher educational levels (upper-middle, OR = 0.761; upper, OR = 0.835) and income (5 minimum wages or more, OR = 0.726) were associated with lower turnover. Being single and younger were associated with higher turnover (OR = 1.413). T2DM patients aged 40-59 (OR = 0.655) and with 5 minimum wages or more (OR = 0.401) experienced less turnover. Being a T2DM male patient increased the risk of experiencing turnover (OR = 1.166). Up to 89% of workers losing IMSS affiliation and moving on to other jobs failed to gain job-related access to health services. Only 9% gained access to the federal workers social security institute (ISSSTE). Turnover across labour market sectors is frequently experienced by the workforce in Mexico, worsening among the elderly and the young, and affecting patients with chronic diseases. This situation needs to be prospectively addressed by health system policies that aim to expand the financial health protection during an employment turnover event.

Are nursing home survey deficiencies higher in facilities with greater staff turnover.

PubMed

Lerner, Nancy B; Johantgen, Meg; Trinkoff, Alison M; Storr, Carla L; Han, Kihye

2014-02-01

To examine CNA and licensed nurse (RN+LPN/LVN) turnover in relation to numbers of deficiencies in nursing homes. A secondary data analysis of information from the National Nursing Home Survey (NNHS) and contemporaneous data from the Online Survey, Certification and Reporting (OSCAR) database. Data were linked by facility as the unit of analysis to determine the relationship of CNA and licensed nurse turnover on nursing home deficiencies. The 2004 NNHS used a multistage sampling strategy to generate a final sample of 1174 nursing homes, which represent 16,100 NHs in the United States. This study focused on the 1151 NNHS facilities with complete deficiency data. Turnover was defined as the total CNAs/licensed nurse full-time equivalents (FTEs) who left during the preceding 3 months (full- and part-time) divided by the total FTE. NHs with high turnover were defined as those with rates above the 75th percentile (25.3% for CNA turnover and 17.9% for licensed nurse turnover) versus all other facilities. This study used selected OSCAR deficiencies from the Quality of Care, Quality of Life, and Resident Behavior categories, which are considered to be more closely related to nursing care. We defined NHs with high deficiencies as those with numbers of deficiencies above the 75th percentile versus all others. Using SUDAAN PROC RLOGIST, we included NNHS sampling design effects and examined associations of CNA/licensed nurse turnover with NH deficiencies, adjusting for staffing, skill mix, bed size, and ownership in binomial logistic regression models. High CNA turnover was associated with high numbers of Quality of Care (OR 1.53, 95% CI 1.10-2.13), Resident Behavior (OR 1.42, 95% CI 1.03-1.97) and total selected deficiencies (OR 1.54, 95% CI 1.12-2.12). Licensed nurse turnover was significantly related to Quality of Care deficiencies (OR 2.06, 95% CI 1.50-2.82) and total selected deficiencies (OR 1.71, 95% CI 1.25-2.33). When both CNA turnover and licensed nurse turnover were included in the same model, high licensed nurse turnover was significantly associated with Quality of Care and total deficiencies, whereas CNA turnover was not associated with that category of deficiencies. Turnover in nursing homes for both licensed nurses and CNAs is associated with quality problems as measured by deficiencies. Copyright © 2014 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

The Effect of Primary Care Provider Turnover on Patient Experience of Care and Ambulatory Quality of Care.

PubMed

Reddy, Ashok; Pollack, Craig E; Asch, David A; Canamucio, Anne; Werner, Rachel M

2015-07-01

Primary care provider (PCP) turnover is common and can disrupt patient continuity of care. Little is known about the effect of PCP turnover on patient care experience and quality of care. To measure the effect of PCP turnover on patient experiences of care and ambulatory care quality. Observational, retrospective cohort study of a nationwide sample of primary care patients in the Veterans Health Administration (VHA). We included all patients enrolled in primary care at the VHA between 2010 and 2012 included in 1 of 2 national data sets used to measure our outcome variables: 326,374 patients in the Survey of Healthcare Experiences of Patients (SHEP; used to measure patient experience of care) associated with 8441 PCPs and 184,501 patients in the External Peer Review Program (EPRP; used to measure ambulatory care quality) associated with 6973 PCPs. Whether a patient experienced PCP turnover, defined as a patient whose provider (physician, nurse practitioner, or physician assistant) had left the VHA (ie, had no patient encounters for 12 months). Five patient care experience measures (from SHEP) and 11 measures of quality of ambulatory care (from EPRP). Nine percent of patients experienced a PCP turnover in our study sample. Primary care provider turnover was associated with a worse rating in each domain of patient care experience. Turnover was associated with a reduced likelihood of having a positive rating of their personal physician of 68.2% vs 74.6% (adjusted percentage point difference, -5.3; 95% CI, -6.0 to -4.7) and a reduced likelihood of getting care quickly of 36.5% vs 38.5% (adjusted percentage point difference, -1.1; 95% CI, -2.1 to -0.1). In contrast, PCP turnover was not associated with lower quality of ambulatory care except for a lower likelihood of controlling blood pressure of 78.7% vs 80.4% (adjusted percentage point difference, -1.44; 95% CI, -2.2 to -0.7). In 9 measures of ambulatory care quality, the difference between patients who experienced no PCP turnover and those who had a PCP turnover was less than 1 percentage point. These effects were moderated by the patients' continuity with their PCP prior to turnover, with a larger detrimental effect of PCP turnover among those with higher continuity prior to the turnover. Primary care provider turnover was associated with worse patient experiences of care but did not have a major effect on ambulatory care quality.

Exercise to Counteract Loss of Bone and Muscle during Androgen Deprivation Therapy in Men with Prostate Cancer

DTIC Science & Technology

2008-08-01

increases 5- to 10-fold after the initiation of ADT19 and that the relative risk of osteoporotic fracture is increased by 30% to 300%.20-22 In 31 men...of bone turnover; serum sex hormones; physical functional performance; quality of life, and risk factors for cardiovascular disease (blood lipids...hormone binding globulin; physical functional performance; and quality of life. Local project support will enable additional assessments of risk

Exercise to Countereact Loss of Bone and Muscle During Androgen Deprivation Therapy in Men with Prostate Cancer

DTIC Science & Technology

2007-05-01

increases 5- to 10-fold after the initiation of ADT14 and that the relative risk of osteoporotic fracture is increased by 30% to 300%.15-17 In 31 men...of bone turnover; serum sex hormones; physical functional performance; quality of life, and risk factors for cardiovascular disease (blood lipids...hormone binding globulin; physical functional performance; and quality of life. Local project support will enable additional assessments of risk factors

Deployment Completion Report.

DTIC Science & Technology

1983-02-24

LEI’I’EMOF C4KDATION IN PRCESS / AWWRED BY HIGHER AUTHORTIY: 25 COMAND LEPI!ERS OF CMNTION: 20 -.ERITORIOS MAST: 0 EEPI F PUBLIC AEAI S N RELEASES: 45...for the work re-U maining. A decision was made to concentrate work on the telephone, public address, and fire alarm connections of the 200 pair cable...the battalion finished the work at NAS. Rather than initiate work in NAVCAMS, the decision was made to shut down the project until turnover thereby

Does a Corresponding Set of Variables for Explaining Voluntary Organizational Turnover Transfer to Explaining Voluntary Occupational Turnover?

ERIC Educational Resources Information Center

Blau, Gary

2007-01-01

This study proposed and tested corresponding sets of variables for explaining voluntary organizational versus occupational turnover for a sample of medical technologists. This study is believed to be the first test of the Rhodes and Doering (1983) occupational change model using occupational turnover data. Results showed that corresponding job…

Estimating Teacher Turnover Costs: A Case Study

ERIC Educational Resources Information Center

Levy, Abigail Jurist; Joy, Lois; Ellis, Pamela; Jablonski, Erica; Karelitz, Tzur M.

2012-01-01

High teacher turnover in large U.S. cities is a critical issue for schools and districts, and the students they serve; but surprisingly little work has been done to develop methodologies and standards that districts and schools can use to make reliable estimates of turnover costs. Even less is known about how to detect variations in turnover costs…

How Teacher Turnover Harms Student Achievement. NBER Working Paper No. 17176

ERIC Educational Resources Information Center

Ronfeldt, Matthew; Lankford, Hamilton; Loeb, Susanna; Wyckoff, James

2011-01-01

Researchers and policymakers often assume that teacher turnover harms student achievement, but recent evidence calls into question this assumption. Using a unique identification strategy that employs grade-level turnover and two classes of fixed-effects models, this study estimates the effects of teacher turnover on over 600,000 New York City 4th…

Measuring Staff Turnover in Nursing Homes

ERIC Educational Resources Information Center

Castle, Nicholas G.

2006-01-01

Purpose: In this study the levels of staff turnover reported in the nursing home literature (1990-2003) are reviewed, as well as the definitions of turnover used in these prior studies. With the use of primary data collected from 354 facilities, the study addresses the various degrees of bias that result, depending on how staff turnover is defined…

A retrospective analysis of employee turnover in the health care setting.

PubMed

Bednar, B; McMullen, N

1998-02-01

Significant factors implicated in staff turnover include: variables in organizational structure; employee characteristics; needs and values, and the nature of tasks performed. This article will present the causative factors related to turnover and the conceptual models of the motivational theorists Maslow, Herzberg, Adams, and Mobley. No quantitative or qualitative research could be found on the potential causes of turnover in freestanding dialysis clinics. The staff turnover of a for-profit dialysis company for a 12 month period will be reported by job title, tenure, and level of job satisfaction.

Turning Over Patient Turnover: An Ethnographic Study of Admissions, Discharges, and Transfers

PubMed Central

Mowinski Jennings, Bonnie; Sandelowski, Margarete; Boshamer, Cary C.; Higgins, Melinda K.

2014-01-01

The impact on nursing work of patient turnover (admissions, discharges, and transfers) became evident in an ethnographic study of turbulence. The patient turnover data were generated from extensive observations, 21 formal interviews, and a year of admission and discharge records on one medical and one surgical unit. Timing of turnover events on the two units differed, but on both units admissions typically interrupted workflow more than did discharges, clustered admissions were more disruptive than staggered admissions, and patient turnover during change of shift was more disruptive than during medication administration. Understanding the complexity of patient turnover will elucidate the work involved and improve the evidence base for nurse staffing, a key determinant of quality and safety of care. PMID:24242196

The effects of autonomy and empowerment on employee turnover: test of a multilevel model in teams.

PubMed

Liu, Dong; Zhang, Shu; Wang, Lei; Lee, Thomas W

2011-11-01

Extending research on voluntary turnover in the team setting, this study adopts a multilevel self-determination theoretical approach to examine the unique roles of individual and social-contextual motivational precursors, autonomy orientation and autonomy support, in reducing team member voluntary turnover. Analysis of multilevel time-lagged data collected from 817 employees on 115 teams indicates that psychological empowerment mediates the main effect of autonomy orientation and the interactive effect of autonomy support and its differentiation on a team member's voluntary turnover. The findings have meaningful implications for the turnover and self-determination literatures as well as for managers who endeavor to prevent voluntary turnover in teams. (c) 2011 APA, all rights reserved.

Primary care provider turnover and quality in managed care organizations.

PubMed

Plomondon, Mary E; Magid, David J; Steiner, John F; MaWhinney, Samantha; Gifford, Blair D; Shih, Sarah C; Grunwald, Gary K; Rumsfeld, John S

2007-08-01

To examine the association between primary care provider turnover in managed care organizations and measures of member satisfaction and preventive care. Retrospective cohort study of a national sample of 615 managed care organizations that reported HEDIS data to the National Committee for Quality Assurance from 1999 through 2001. Multivariable hierarchical regression modeling was used to evaluate the association between health plan primary care provider turnover rate and member satisfaction and preventive care measures, including childhood immunization, well-child visits, cholesterol, diabetes management, and breast and cervical cancer screening, adjusting for patient and organizational characteristics, time, and repeated measures. The median primary care provider turnover rate was 7.1% (range, 0%-53.3%). After adjustment for plan characteristics, health plans with higher primary care provider turnover rates had significantly lower measures of member satisfaction, including overall rating of healthcare (P < .01). A 10% higher primary care provider turnover rate was associated with 0.9% fewer members rating high overall satisfaction with healthcare. Health plans with higher provider turnover rates also had lower rates of preventive care, including childhood immunization (P = .045), well-child visits (P = .002), cholesterol screening after cardiac event (P = .042), and cervical cancer screening (P = .024). For example, a 10% higher primary care provider turnover was associated with a 2.7% lower rate of child-members receiving well-child visits in the first 15 months of life. Primary care provider turnover is associated with several measures of care quality, including aspects of member satisfaction and preventive care. Future studies should evaluate whether interventions to reduce primary care provider turnover can improve quality of care and patient outcomes.

Work-to-family conflict as a mediator of the relationship between job satisfaction and turnover intention.

PubMed

Chen, I-Hui; Brown, Roger; Bowers, Barbara J; Chang, Wen-Yin

2015-10-01

To investigate the mediating effect of work-to-family conflict on the relationship between job satisfaction and turnover intention among licensed nurses in long-term care settings. The considerable research on turnover in long-term care has primarily focused on the impact of job satisfaction on turnover intention. Given the well-documented high turnover rate in nursing home staffing, dissatisfaction is expected to continue. Alternatives (e.g. reduction in work-to-family conflict) for reducing turnover under the circumstance of job dissatisfaction have not been investigated extensively. A cross-sectional mailed survey. A convenience sample comprising 200 nurses from 25 private nursing homes in Central Taiwan was created. Data were collected from nurses about their level of turnover intention, job satisfaction and work-to-family conflict in 2012. A composite indicator structural equation model was used to examine the mediation model of this study. Overall, 186 nurses (93%) returned the completed questionnaires. Consistent with published research from other countries, turnover intention in our study was significantly and negatively associated with job satisfaction and significantly and positively associated with work-to-family conflict. In addition, job dissatisfaction indirectly influenced turnover intention through high work-to-family conflict. Findings from this study indicate the importance of work-to-family conflict to nurse turnover. While work setting has a strong, well-documented influence on job satisfaction, limiting job satisfaction efforts to work setting improvements may not yield the hoped-for results unless work-to-family conflict is also considered and addressed. © 2015 John Wiley & Sons Ltd.

The employee retention triad in health care: Exploring relationships amongst organisational justice, affective commitment and turnover intention.

PubMed

Perreira, Tyrone A; Berta, Whitney; Herbert, Monique

2018-04-01

To increase understanding of the relationships between organisational justice, affective commitment and turnover intention in health care. Turnover in health care is a serious concern, as it contributes to the global nursing shortage and is associated with declines in quality of care, patient safety and patient outcomes. Turnover also impacts care teams and is associated with decreased staff cohesion and morale. A survey was developed and administered to frontline nurses working in the Province of Ontario, Canada. The data were used to test a hypothetical model developed from a review of the literature. The relationships amongst the three constructs were evaluated using structural equation modelling and mediation analysis. The hypothesised model was generally supported, although we were limited to considerations of interpersonal justice, affective commitment to one's organisation and turnover intention. Interpersonal justice is associated with affective commitment to one's organisation, which is negatively associated with turnover intention. Interpersonal justice was also found to be directly and negatively associated with turnover intention. Affective commitment to one's organisation was also found to mediate the relationship between interpersonal justice and turnover intention. The examination of relationships within the "employee retention triad" in a single, comprehensive model is novel and provides new information regarding relational complexity and insights into what healthcare leaders can do to retain employees. Reducing turnover may help to decrease some of the stressors related to turnover for clinical staff remaining at the organisation such as constant onboarding and orientation of new hires, working with less experienced staff and increased workload due to decreased staffing. © 2018 John Wiley & Sons Ltd.

Aging of perennial cells and organ parts according to the programmed aging paradigm.

PubMed

Libertini, Giacinto; Ferrara, Nicola

2016-04-01

If aging is a physiological phenomenon-as maintained by the programmed aging paradigm-it must be caused by specific genetically determined and regulated mechanisms, which must be confirmed by evidence. Within the programmed aging paradigm, a complete proposal starts from the observation that cells, tissues, and organs show continuous turnover: As telomere shortening determines both limits to cell replication and a progressive impairment of cellular functions, a progressive decline in age-related fitness decline (i.e., aging) is a clear consequence. Against this hypothesis, a critic might argue that there are cells (most types of neurons) and organ parts (crystalline core and tooth enamel) that have no turnover and are subject to wear or manifest alterations similar to those of cells with turnover. In this review, it is shown how cell types without turnover appear to be strictly dependent on cells subjected to turnover. The loss or weakening of the functions fulfilled by these cells with turnover, due to telomere shortening and turnover slowing, compromises the vitality of the served cells without turnover. This determines well-known clinical manifestations, which in their early forms are described as distinct diseases (e.g., Alzheimer's disease, Parkinson's disease, age-related macular degeneration, etc.). Moreover, for the two organ parts (crystalline core and tooth enamel) without viable cells or any cell turnover, it is discussed how this is entirely compatible with the programmed aging paradigm.

The relationship between job satisfaction, work stress, work–family conflict, and turnover intention among physicians in Guangdong, China: a cross-sectional study

PubMed Central

Lu, Yong; Hu, Xiao-Min; Huang, Xiao-Liang; Zhuang, Xiao-Dong; Guo, Pi; Feng, Li-Fen; Hu, Wei; Chen, Long; Zou, Huachun; Hao, Yuan-Tao

2017-01-01

Objective To investigate the relationship between job satisfaction, work stress, work–family conflict and turnover intention, and explore factors associated with turnover intention, among physicians in Guangdong Province, China. Methods From August to October 2013, physicians completed questionnaires and scales with regard to their job satisfaction, work stress, work–family conflict, and turnover intention. Binary logistic regression and structural equation modelling (SEM) were used in data analysis. Results A total of 3963 physicians were approached, with 3563 completing the questionnaire. The mean score of the overall perception of turnover intention of physicians who worked in Guangdong was 2.71 on a scale ranging from 1 to 6. Hours worked per week, working in an urban/rural area, type of institution, and age significantly impacted on turnover intention. Turnover intention was directly and negatively related to job satisfaction, and it was directly, indirectly and positively related to work stress and work–family conflict. Conclusion Job satisfaction, work stress, work–family conflict, hours worked per week, working in an urban/rural area, types of institution and age are influencing factors of turnover intention. Reducing working hours, raising salary, providing more opportunities for career development and training, supporting and encouraging physicians by senior managers could potentially contribute to the reduction in turnover intention. PMID:28501813

The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis.

PubMed

Rytter, Rose-Marie

2013-09-01

The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots <1 mm (5-6 year(-1)) and 1-2 mm (0.9-2.8 year(-1)) were not affected by changes in N or water availability. Fine root production (<1 mm) differed between Alnus and Salix, and between treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited < unlimited < N limited. Few treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (≤2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light.

Interactions Between Pinus taeda (loblolly) Fine Roots and Soil Fungi: Impacts of Elevated CO2, N Availability, and Spatial Distribution of Fungi on Fine Root Persistence and Turnover

NASA Astrophysics Data System (ADS)

Strand, A.; Beidler, K.; McGlinn, D.; Pritchard, S. G.

2016-12-01

Fine root turnover represents the most significant mode of flux from plants into soil C pools. Unfortunately fine root senescence and decomposition, processes critical in turnover, are particularly understudied. For example, little is known about either the factors that influence fine-root decomposition or the fate of compounds they contain during root death. Better understanding fine root senescence and decomposition should reduce uncertainty associated with global climate models; including re-uptake of materials in dying leaves into these models has already been shown to increase their accuracy. Over 4400 individual fine-roots and 4734 rhizomorphs were tracked from initiation until disintegration over 12 years using minirhizotrons at the Duke FACE site. Image-based approaches such as minirhizotrons cannot directly assess fine-root physiological status. To assess fine-root function directly, we are now conducting manipulative experiments in P. taeda in which fine-root senescence is induced through two treatments, steam- and direct hand-girdling. Physiological status is then assessed by examining gene-expression, root anatomy and chemical composition of manipulated roots. Changing [CO2] did not change persistence times for roots, but did impact rhizomorph persistence. Both roots and rhizomorphs showed interactions between effects of N and CO2 on persistence. Most interesting is the interaction between fine-roots and rhizomorphs: fine root persistence times are reduced in the presence of rhizomorphs, but this effect depends on the amount of N available. Finally, we found experimentally inducing senescence via steam girdling to be very effective relative to hand-girdling. These results provide evidence of the importance of priming on function of soil fungi and the role of N availability on fine-root turnover. The ability to stimulate fine-root senescence provides a powerful experimental tool to examine the fates of resources contained in fine-root pools as these roots turn over.

Measuring Worker Turnover in Long-Term Care: Lessons from the Better Jobs Better Care Demonstration

ERIC Educational Resources Information Center

Piercy, Kathleen Walsh, Ed.; Barry, Theresa; Kemper, Peter; Brannon, S. Diane

2008-01-01

Purpose: Turnover among direct-care workers (DCWs) continues to be a challenge in long-term care. Both policy makers and provider organizations recognize this issue as a major concern and are designing efforts to reduce turnover among these workers. However, there is currently no standardized method of measuring turnover to define the scope of the…

The Day-to-Day Reality of Teacher Turnover in Preschool Classrooms: An Analysis of Classroom Context and Teacher, Director, and Parent Perspectives

ERIC Educational Resources Information Center

Cassidy, Deborah J.; Lower, Joanna K.; Kintner-Duffy, Victoria L.; Hegde, Archana V.; Shim, Jonghee

2011-01-01

The purpose of the current study is to examine teacher turnover comprehensively by triangulating the experiences of teachers, directors, parents, and children through actual, "real-time" turnover transitions. We intentionally examined turnover with a small sample size (N = 13 classrooms) to facilitate comprehensive data collection utilizing…

When the Going Gets Tough: Direct, Buffering and Indirect Effects of Social Support on Turnover Intention

ERIC Educational Resources Information Center

Pomaki, Georgia; DeLongis, Anita; Frey, Daniela; Short, Kathy; Woehrle, Trish

2010-01-01

We examined the role of social support in turnover intention among new teachers. First, we tested and found evidence for a direct negative relationship between social support and turnover intention. Second, we tested the social support buffer hypothesis, and found that teachers with higher social support had lower turnover intention in the face of…

Listening to the Voices of Children in Foster Care: Youths Speak out about Child Welfare Workforce Turnover and Selection

ERIC Educational Resources Information Center

Strolin-Goltzman, Jessica; Kollar, Sharon; Trinkle, Joanne

2010-01-01

Child welfare workforce turnover rates across private and public child welfare agencies are concerning. Although research about the causes of child welfare workforce turnover has been plentiful, empirical studies on the effects of turnover on child outcomes are sparse. Furthermore, the voices and experiences of youths within the system have been…

Further Clarifying Proximal Withdrawal States and the Turnover Criterion Space: Comment on Hom, Mitchell, Lee, and Griffeth (2012)

ERIC Educational Resources Information Center

Maertz, Carl P., Jr.

2012-01-01

In "Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion," Hom, Mitchell, Lee, and Griffeth (2012) brought together many of the most important content and process factors in the employee turnover literature. In this paper, I attempt to clarify the true contributions of this framework for the turnover area…

A Ministudy of employee turnover in US hospitals.

PubMed

Collins, Sandra K; McKinnies, Richard C; Matthews, Eric P; Collins, Kevin S

2015-01-01

A ministudy was conducted to collect self-reported employee turnover rates in US hospitals. The results indicate many hospitals are struggling with high employee turnover rates. Widespread variances in ratings were observed across hospitals, which may be due to lack of consistency in how they each calculate their employee turnover. This makes benchmarking for the purposes of performance improvement challenging.

Impact of resilience and job involvement on turnover intention of new graduate nurses using structural equation modeling.

PubMed

Yu, Mi; Lee, Haeyoung

2018-03-06

Nurses' turnover intention is not just a result of their maladjustment to the field; it is an organizational issue. This study aimed to construct a structural model to verify the effects of new graduate nurses' work environment satisfaction, emotional labor, and burnout on their turnover intention, with consideration of resilience and job involvement, and to test the adequacy of the developed model. A cross-sectional study and a structural equation modelling approach were used. A nationwide survey was conducted of 371 new nurses who were working in hospitals for ≤18 months between July and October, 2014. The final model accounted for 40% of the variance in turnover intention. Emotional labor and burnout had a significant positive direct effect and an indirect effect on nurses' turnover intention. Resilience had a positive direct effect on job involvement. Job involvement had a negative direct effect on turnover intention. Resilience and job involvement mediated the effect of work environment satisfaction, emotional labor, and burnout on turnover intention. It is important to strengthen new graduate nurses' resilience in order to increase their job involvement and to reduce their turnover intention. © 2018 Japan Academy of Nursing Science.

Clinical supervision, emotional exhaustion, and turnover intention: a study of substance abuse treatment counselors in the Clinical Trials Network of the National Institute on Drug Abuse.

PubMed

Knudsen, Hannah K; Ducharme, Lori J; Roman, Paul M

2008-12-01

An intriguing hypothesis is that clinical supervision may protect against counselor turnover. This idea has been mentioned in recent discussions of the substance abuse treatment workforce. To test this hypothesis, we extend our previous research on emotional exhaustion and turnover intention among counselors by estimating the associations between clinical supervision and these variables in a large sample (N = 823). An exploratory analysis reveals that clinical supervision was negatively associated with emotional exhaustion and turnover intention. Given our previous findings that emotional exhaustion and turnover intention were associated with job autonomy, procedural justice, and distributive justice, we estimate a structural equation model to examine whether these variables mediated clinical supervision's associations with emotional exhaustion and turnover intention. These data support the fully mediated model. We found that the perceived quality of clinical supervision is strongly associated with counselors' perceptions of job autonomy, procedural justice, and distributive justice, which are, in turn, associated with emotional exhaustion and turnover intention. These data offer support for the protective role of clinical supervision in substance abuse treatment counselors' turnover and occupational well-being.

Turnover intention among intensive care unit nurses in Alexandria, Egypt.

PubMed

Mosallam, Rasha; Hamidi, Samer; Elrefaay, Manal

2015-06-01

Given the difficulty in recruiting new nurses, it is imperative to retain those already in the profession. This cross-sectional study explored the relationship of demographic and work-related factors, burnout, conflict management and relationship between nurses and physicians on turnover intentions among ICU nurses in eight major hospitals in Alexandria, Egypt. Data on burnout, conflict management, nurse-physician communication, and turnover intention were collected by surveying 100 nurses in eight hospitals in Alexandria governorate. All nurses at the ICU of selected hospitals were approached (n=100) and a 47-item Likert scale questionnaire was administered to explore the factors affecting the turnover intention of ICU nurses in Alexandria. ICU nurses exhibited a mean score for turnover intention of 3.23 (mean score percentage 65.0%). There was a moderately positive statistically significant correlation between turnover intention and emotional exhaustion (r=0.29, P<0.05), nurse-physician communication (r=0.25, P<0.05), and age (r=0.21, P<0.05). The predicting factors for turnover intention were emotional exhaustion and age. Nurses turnover intention at the ICU of the selected hospitals is high and is significantly associated with nurses' emotional exhaustion, poor nurse-physician communication, and nurses age.

Understanding the factors that determine registered nurses' turnover intentions.

PubMed

Osuji, Joseph; Uzoka, Faith-Michael; Aladi, Flora; El-Hussein, Mohammed

2014-01-01

Turnover among registered nurses (RNs) produces a negative impact on the health outcomes of any health care organization. It is also recognized universally as a problem in the nursing profession. Little is known about the turnover intentions and career orientations of RNs working in Calgary, Alberta, Canada. The aim of this study is to contribute to the knowledge of and to advance the discussion on the turnover of nursing professionals. The study population consisted of RNs employed in the five major hospitals in Calgary. There were 193 surveys returned, representing a response rate of 77.2%. The results show that age and education have a negative effect on turnover intention. Education was found to have a significant negative effect on career satisfaction but not on job satisfaction and organizational commitment. Length of service has a significant negative effect on turnover intention. Role ambiguity has significant highly negative effect on career satisfaction. Growth opportunity and supervisor support have a very significant positive effect on job satisfaction, career satisfaction, and organizational commitment. External career opportunities and organizational commitment do not seem to have a significant effect on turnover intention. Career satisfaction, on the other hand, had negative significant effects on turnover intention.

The mediating role of job satisfaction between leader-member exchange and turnover intentions.

PubMed

Han, Guohong Helen; Jekel, Marc

2011-01-01

The aim of the present study was to investigate whether job satisfaction mediates between leader-member exchange and nurse turnover intentions. Limited knowledge is available on the mediating role of job satisfaction between leader-member exchange and turnover intentions in the nursing field. This is a cross-sectional survey study. Data were collected in a US hospital. Higher leader-member exchange was associated with lower turnover intentions (β=-0.41, P<0.001). Leader-member exchange was positively related to one's job satisfaction (β=0.50, P<0.001). Job satisfaction was negatively related to turnover intentions (β=-0.64, P<0.001). When leader-member exchange and job satisfaction were both controlled for, the link between leader-member exchange and turnover intentions was no longer significant (β=-0.12, P>0.05). Job satisfaction mediates the link between leader-member exchange and turnover intentions. The present study reinforces the significant role of managers. Nurse managers can try to cultivate a good relationship with the nurses. This can enhance nurses' job satisfaction and in turn lower their turnover intentions. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

Actin turnover maintains actin filament homeostasis during cytokinetic ring contraction

PubMed Central

Palani, Saravanan; Sommese, Ruth; Kamnev, Anton; Hatano, Tomoyuki; Sivaramakrishnan, Sivaraj

2017-01-01

Cytokinesis in many eukaryotes involves a tension-generating actomyosin-based contractile ring. Many components of actomyosin rings turn over during contraction, although the significance of this turnover has remained enigmatic. Here, using Schizosaccharomyces japonicus, we investigate the role of turnover of actin and myosin II in its contraction. Actomyosin ring components self-organize into ∼1-µm-spaced clusters instead of undergoing full-ring contraction in the absence of continuous actin polymerization. This effect is reversed when actin filaments are stabilized. We tested the idea that the function of turnover is to ensure actin filament homeostasis in a synthetic system, in which we abolished turnover by fixing rings in cell ghosts with formaldehyde. We found that these rings contracted fully upon exogenous addition of a vertebrate myosin. We conclude that actin turnover is required to maintain actin filament homeostasis during ring contraction and that the requirement for turnover can be bypassed if homeostasis is achieved artificially. PMID:28655757

AL-1576, an aldose reductase inhibitor (ARI), did not prevent the decrease of norepinephrine turnover in diabetic rats.

PubMed

Yen, T T; Fuller, R W; Broderick, C L; Hemrick-Luecke, S K; Perry, K W

1988-08-01

ONO-2235 [(E)-3-carboxymethyl-5-[(2E)-2-methyl-3-phenyl-propenylidene]rhodanine], an ARI, was reported to prevent significantly the decrease of norepinephrine (NE) turnover in three tissues of streptozotocin (STZ)-diabetic rats (1). To examine whether the partial restoration of NE turnover by ONO-2235 is related to its ARI activity, the effect of another ARI, AL-1576 [spiro(2,7-difluoro-9H-fluoren-9, 4'-imidazoline)-2'5'-dione], on NE turnover in STZ rats was investigated. STZ caused an accumulation of sorbitol in the lens and decreased NE turnover in interscapular brown adipose tissue (IBAT), heart and pancreas. AL-1576 totally prevented the accumulation of sorbitol in the lens but had no effect on the decreased NE turnover in all three tissues. These results suggest that the partial prevention of NE turnover decrease by ONO-2235 may not have been mediated by its ARI activity.

Executive turnover: the influence of dispersion and other pay system characteristics.

PubMed

Messersmith, Jake G; Guthrie, James P; Ji, Yong-Yeon; Lee, Jeong-Yeon

2011-05-01

Using tournament theory as a guiding theoretical framework, in this study, we assess the organizational implications of pay dispersion and other pay system characteristics on the likelihood of turnover among individual executives in organizational teams. Specifically, we estimate the effect of these pay system characteristics on executive turnover decisions. We use a multi-industry, multilevel data set composed of executives in publicly held firms to assess the effects of pay dispersion at the individual level. Consistent with previous findings, we find that pay dispersion is associated with an increased likelihood of executive turnover. In addition, we find that other pay characteristics also affect turnover, both directly and through a moderating effect on pay dispersion. Turnover is more likely when executives receive lower portions of overall top management team compensation and when they have more pay at risk. These conditions also moderate the relationship between pay dispersion and individual turnover decisions, as does receiving lower compensation relative to the market.

Comparison of Reasons for Nurse Turnover in Magnet® and Non-Magnet Hospitals.

PubMed

Park, Shin Hye; Gass, Stephanie; Boyle, Diane K

2016-05-01

The aim of this study is to compare rates and reasons for registered nurse (RN) turnover by Magnet® status. Although lower RN turnover rates in Magnet hospitals have been documented well in the literature, little is known about specific separation reasons for RN turnover and whether the reasons differ between Magnet and non-Magnet hospitals. This descriptive, correlational study analyzed unit-level 2013 National Database of Nursing Quality Indicators® turnover data (2,958 units; 497 hospitals). Poisson regression and Wilcoxon-Mann-Whitney test were used. Registered nurse turnover due to environment-related reasons was higher on units in non-Magnet hospitals than units in Magnet hospitals. Units in non-Magnet hospitals had 4.684 times higher turnover rates due to staffing/workload and 1.439 times higher rates due to work schedules than did units in Magnet hospitals. Nursing administrators in both Magnet and non-Magnet hospitals need to continually strive to improve unit work environments, particularly staffing and workload conditions and work scheduling.

Turnover, staffing, skill mix, and resident outcomes in a national sample of US nursing homes.

PubMed

Trinkoff, Alison M; Han, Kihye; Storr, Carla L; Lerner, Nancy; Johantgen, Meg; Gartrell, Kyungsook

2013-12-01

The authors examined the relationship of staff turnover to selected nursing home quality outcomes, in the context of staffing and skill mix. Staff turnover is a serious concern in nursing homes as it has been found to adversely affect care. When employee turnover is minimized, better care quality is more likely in nursing homes. Data from the National Nursing Home Survey, a nationally representative sample of US nursing homes, were linked to Nursing Home Compare quality outcomes and analyzed using logistic regression. Nursing homes with high certified nursing assistant turnover had significantly higher odds of pressure ulcers, pain, and urinary tract infections even after controlling for staffing, skill mix, bed size, and ownership. Nurse turnover was associated with twice the odds of pressure ulcers, although this was attenuated when staffing was controlled. This study suggests turnover may be more important in explaining nursing home (NH) outcomes than staffing and skill mix and should therefore be given greater emphasis.

A longitudinal study of the moderating role of extraversion: leader-member exchange, performance, and turnover during new executive development.

PubMed

Bauer, Talya N; Erdogan, Berrin; Liden, Robert C; Wayne, Sandy J

2006-03-01

Identifying factors that help or hinder new executives in "getting up to speed" quickly and remaining with an organization is vital to maximizing the effectiveness of executive development. The current study extends past research by examining extraversion as a moderator of relationships between leader-member exchange (LMX) and performance, turnover intentions, and actual turnover for an executive sample. The sample consisted of 116 new executives who were surveyed prior to starting their employment and at 3 months postentry. A total of 67 senior executives rated these new executives in terms of overall performance at 6 months postentry. Turnover data were gathered from company records 3 1/2 years later. Hierarchical regression results showed that LMX was not related to performance or turnover intentions for those high in extraversion; but for individuals low in extraversion, there was a relation between LMX, performance, and turnover intentions. Furthermore, survival analyses showed that LMX was only related to turnover-hazard rate for individuals low in extraversion.

Mental health pharmacists as interim prescribers

PubMed Central

2017-01-01

Introduction: Turnover leading to fluctuations in prescriber availability presents many challenges, most notably in access to and continuity of care. In 2015, the Veterans Affairs Eastern Colorado Healthcare System (VA ECHCS) experienced a period of significant mental health prescriber turnover leading to patient utilization of psychiatric emergency services (PES) for nonemergent medication management. The resulting increase in volume placed excessive stress on PES prescribers. Mental health pharmacists have opportunities to provide interim medication management while patients are between prescribers. Methods: This study was a retrospective, cohort study of patients unassigned to an outpatient mental health prescriber due to prescriber turnover, receiving care at VA ECHCS between October 1, 2015, and February 28, 2016. The primary outcome was the number of pharmacist interventions performed. Secondary outcomes characterize the interventions performed and describe the change in the mean monthly volume of patients presenting to PES. Results: In this veteran population, 152 interventions were performed in 81 unique patients. The most common intervention was prescription renewals (80%). Interventions most commonly involved antidepressants (28%), antipsychotics (10%), and mood stabilizers (10%). Before initiation of the clinic, Denver VA PES experienced a mean of 300 monthly visits. After clinic implementation, PES visits decreased significantly to a mean of 237 visits per month (P = .041). Discussion: The pharmacist interim prescriber clinic was associated with a significant decrease in mean number of patients seen per month in PES. The success of the clinic also contributed to interest by the mental health service to expand clinical pharmacy services.

Vitamin D supplementation, bone turnover, and inflammation in HIV-infected patients.

PubMed

Benguella, L; Arbault, A; Fillion, A; Blot, M; Piroth, C; Denimal, D; Duvillard, L; Ornetti, P; Chavanet, P; Maillefert, J-F; Piroth, L

2018-04-13

To assess whether vitamin D supplementation could be associated with a modification of inflammatory markers and bone turnover in HIV-1-infected patients. Patients who participated in an initial survey in 2010 and who were followed in the same department were included in a new study in 2012. Between 2010 and 2012, vitamin D supplementation was offered to patients presenting with hypovitaminosis D as per appropriate guidelines. Clinical examinations were performed, and fasting blood samples were taken for inflammation and bone marker evaluations. Of the 263 patients who participated in the 2010 study, 198 were included in the 2012 study. Hypovitaminosis D was observed in 47% (36/77) of participants supplemented as per appropriate guidelines, in 78% (75/97) of transiently or incompletely supplemented participants, and in 71% (17/24) of non-supplemented participants (mainly because vitamin D levels in 2010 were normal). No significant correlation between vitamin D supplementation and the 2-year inflammation outcome (IL-6 and hsCRP) or C-terminal telopeptide levels was observed. However, a decrease in IL6 levels over the 2 years significantly correlated with reaching a normal vitamin D level (OR=0.89 per+1pg/mL IL6 increase, 95% CI=0.81-0.97, P=0.015). Vitamin D supplementation decreases the risk of hypovitaminosis D but does not decrease the risk of inflammation nor bone turnover, unless normal 25-OH vitamin D levels are reached. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Relationships between compassion fatigue, burnout, and turnover intention in Korean hospital nurses.

PubMed

Sung, Kiwol; Seo, Youngsook; Kim, Jee Hee

2012-12-01

This study aimed to identify relationships between compassion fatigue, burnout, and turnover intention in Korean hospital nurses. In total, 142 hospital nurses were surveyed as part of data collection. Data related to compassion fatigue, burnout, and turnover intention were collected using a questionnaire between May 2011 and September 2011. The data analysis was performed using PASW 19.0 program, which included one-way ANOVA, independent t-tests, Pearson's correlation coefficient, and hierarchical regression analysis. This study detected a positive correlation between compassion fatigue and burnout(r=.37, p<.001), and turnover intention(r=.55, p<.001). Compassion fatigue accounted for 29.6% of the variance for turnover intention among Korean hospital nurses. The results indicate that it is necessary to reduce compassion fatigue, and turnover intention among Korean hospital nurses.

[Predictors of Turnover among New Nurses using Multilevel Survival Analysis].

PubMed

Kim, Suhee; Lee, Kyongeun

2016-10-01

The purpose of this study was to examine factors influencing new graduate nurse turnover. This study was carried out as a secondary analysis of data from the 2010 Graduates Occupational Mobility Survey (GOMS). A total of 323 nurses were selected for analysis concerning reasons for turnover. Data were analyzed using descriptive statistics and multilevel survival analysis. About 24.5% of new nurses left their first job within 1 year of starting their jobs. Significant predictors of turnover among new nurse were job status, monthly income, job satisfaction, the number of hospitals in region, and the number of nurses per 100 beds. New graduate nurses are vulnerable to turnover. In order to achieve the best health of the nation, policy approaches and further studies regarding reducing new graduate nurse turnover are needed.

Application of two neural network paradigms to the study of voluntary employee turnover.

PubMed

Somers, M J

1999-04-01

Two neural network paradigms--multilayer perceptron and learning vector quantization--were used to study voluntary employee turnover with a sample of 577 hospital employees. The objectives of the study were twofold. The 1st was to assess whether neural computing techniques offered greater predictive accuracy than did conventional turnover methodologies. The 2nd was to explore whether computer models of turnover based on neural network technologies offered new insights into turnover processes. When compared with logistic regression analysis, both neural network paradigms provided considerably more accurate predictions of turnover behavior, particularly with respect to the correct classification of leavers. In addition, these neural network paradigms captured nonlinear relationships that are relevant for theory development. Results are discussed in terms of their implications for future research.

Polysome Turnover During Amino Acid Starvation in Escherichia coli

PubMed Central

Ron, Eliora Z.

1971-01-01

The experiments presented in this paper support earlier evidence that ribosomes are released from polysomes when they encounter a codon for which no charged transfer ribonucleic acid is available. However, it is further shown that these ribosomes then reinitiate and resume translation. The size and the level of polysomes during deprival of an amino acid is a function of the frequency with which that particular amino acid appears in cellular proteins. Polysomes from starved cells are more stable than those from growing cells, and, moreover, polysomes from starved relaxed strains are more stable than those from starved stringent strains. PMID:4941559

Exploring the Efficacy of the Government’s Current Use of Past Performance Information

DTIC Science & Technology

2013-12-03

during proposal evaluations— perhaps informed by better past performance information? While the impact of the past performance evaluation is speculative...turnover as having a potential impact on supplier evaluations over time. Therefore, it is posited that ^Åèìáëáíáçå=oÉëÉ~êÅÜ=mêçÖê~ã= dê~Çì~íÉ=pÅÜççä...Therefore, it is posited that H12: There will be a positive relationship between communication frequency and perceived accuracy of evaluations. H13

Origin, evolution, and population genetics of the selfish Segregation Distorter gene duplication in European and African populations of Drosophila melanogaster.

PubMed

Brand, Cara L; Larracuente, Amanda M; Presgraves, Daven C

2015-05-01

Meiotic drive elements are a special class of evolutionarily "selfish genes" that subvert Mendelian segregation to gain preferential transmission at the expense of homologous loci. Many drive elements appear to be maintained in populations as stable polymorphisms, their equilibrium frequencies determined by the balance between drive (increasing frequency) and selection (decreasing frequency). Here we show that a classic, seemingly balanced, drive system is instead characterized by frequent evolutionary turnover giving rise to dynamic, rather than stable, equilibrium frequencies. The autosomal Segregation Distorter (SD) system of the fruit fly Drosophila melanogaster is a selfish coadapted meiotic drive gene complex in which the major driver corresponds to a partial duplication of the gene Ran-GTPase activating protein (RanGAP). SD chromosomes segregate at similar, low frequencies of 1-5% in natural populations worldwide, consistent with a balanced polymorphism. Surprisingly, our population genetic analyses reveal evidence for parallel, independent selective sweeps of different SD chromosomes in populations on different continents. These findings suggest that, rather than persisting at a single stable equilibrium, SD chromosomes turn over frequently within populations. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Examining the job search-turnover relationship: the role of embeddedness, job satisfaction, and available alternatives.

PubMed

Swider, Brian W; Boswell, Wendy R; Zimmerman, Ryan D

2011-03-01

This study examined factors that may help explain under what conditions employee job search effort may most strongly (or weakly) predict subsequent turnover. As predicted, the job search-turnover relationship was stronger when employees had lower levels of job embeddedness and job satisfaction and higher levels of available alternatives. These findings suggest that there may be a number of factors interacting to influence employees' turnover decisions, indicating greater complexity to the process than described in prominent sequential turnover models. PsycINFO Database Record (c) 2011 APA, all rights reserved.

The Effect of Primary Care Provider Turnover on Patient Experience of Care and Ambulatory Quality of Care

PubMed Central

Reddy, Ashok; Pollack, Craig E.; Asch, David A.; Canamucio, Anne; Werner, Rachel M.

2017-01-01

IMPORTANCE Primary care provider (PCP) turnover is common and can disrupt patient continuity of care. Little is known about the effect of PCP turnover on patient care experience and quality of care. OBJECTIVE To measure the effect of PCP turnover on patient experiences of care and ambulatory care quality. DESIGN, SETTING, AND PARTICIPANTS Observational, retrospective cohort study of a nationwide sample of primary care patients in the Veterans Health Administration (VHA). We included all patients enrolled in primary care at the VHA between 2010 and 2012 included in 1 of 2 national data sets used to measure our outcome variables: 326 374 patients in the Survey of Healthcare Experiences of Patients (SHEP; used to measure patient experience of care) associated with 8441 PCPs and 184 501 patients in the External Peer Review Program (EPRP; used to measure ambulatory care quality) associated with 6973 PCPs. EXPOSURES Whether a patient experienced PCP turnover, defined as a patient whose provider (physician, nurse practitioner, or physician assistant) had left the VHA (ie, had no patient encounters for 12 months). MAIN OUTCOMES AND MEASURES Five patient care experience measures (from SHEP) and 11 measures of quality of ambulatory care (from EPRP). RESULTS Nine percent of patients experienced a PCP turnover in our study sample. Primary care provider turnover was associated with a worse rating in each domain of patient care experience. Turnover was associated with a reduced likelihood of having a positive rating of their personal physician of 68.2% vs 74.6% (adjusted percentage point difference, −5.3; 95% CI, −6.0 to −4.7) and a reduced likelihood of getting care quickly of 36.5% vs 38.5% (adjusted percentage point difference, −1.1; 95% CI, −2.1 to −0.1). In contrast, PCP turnover was not associated with lower quality of ambulatory care except for a lower likelihood of controlling blood pressure of 78.7% vs 80.4% (adjusted percentage point difference, −1.44; 95% CI, −2.2 to −0.7). In 9 measures of ambulatory care quality, the difference between patients who experienced no PCP turnover and those who had a PCP turnover was less than 1 percentage point. These effects were moderated by the patients’ continuity with their PCP prior to turnover, with a larger detrimental effect of PCP turnover among those with higher continuity prior to the turnover. CONCLUSIONS AND RELEVANCE Primary care provider turnover was associated with worse patient experiences of care but did not have a major effect on ambulatory care quality. PMID:25985320

Nitrates and bone turnover (NABT) - trial to select the best nitrate preparation: study protocol for a randomized controlled trial

PubMed Central

2013-01-01

Background Organic nitrates uncouple bone turnover, improve bone mineral density, and improve trabecular and cortical components of bone. These changes in turnover, strength and geometry may translate into an important reduction in fractures. However, before proceeding with a large fracture trial, there is a need to identify the nitrate formulation that has both the greatest efficacy (with regards to bone turnover markers) and gives the fewest headaches. Ascertaining which nitrate formulation this may be is the purpose of the current study. Methods and design This will be an open-label randomized, controlled trial conducted at Women’s College Hospital comparing five formulations of nitrates for their effects on bone turnover markers and headache. We will recruit postmenopausal women age 50 years or older with no contraindications to nitroglycerin. Our trial will consist of a run-in phase and a treatment phase. We will enroll 420 women in the run-in phase, each to receive all of the 5 potential treatments in random order for 2 days, each with a 2-day washout period between treatments. Those who tolerate all formulations will enter the 12-week treatment phase and be randomly assigned to one of five groups: 0.3 mg sublingual nitroglycerin tablet, 0.6 mg of the sublingual tablet, a 20 mg tablet of isosorbide mononitrate, a 160 mg nitroglycerin transdermal patch (used for 8 h), and 15 mg of nitroglycerin ointment as used in a previous trial by our group. We will continue enrolment until we have randomized 210 women or 35 women per group. Concentrations of bone formation (bone-specific alkaline phosphatase and procollagen type I N-terminal propeptide) and bone resorption (C-telopeptides of collagen crosslinks and N-terminal crosslinks of collagen) agents will be measured in samples taken at study entry (the start of the run in phase) and 12 weeks. Subjects will record the frequency and severity of headaches daily during the run-in phase and then monthly after that. We will use the ‘multiple comparisons with the best’ approach for data analyses, as this strategy allows practical considerations of ease of use and tolerability to guide selection of the preparation for future studies. Discussion Data from this protocol will be used to develop a randomized, controlled trial of nitrates to prevent osteoporotic fractures. Trial registration ClinicalTrials.gov Identifier: NCT01387672. Controlled-Trials.com: ISRCTN08860742. PMID:24010992

Elevated brain serotonin turnover in patients with depression: effect of genotype and therapy.

PubMed

Barton, David A; Esler, Murray D; Dawood, Tye; Lambert, Elisabeth A; Haikerwal, Deepak; Brenchley, Celia; Socratous, Florentia; Hastings, Jacqueline; Guo, Ling; Wiesner, Glen; Kaye, David M; Bayles, Richard; Schlaich, Markus P; Lambert, Gavin W

2008-01-01

The biological basis for the development of major depressive disorder (MDD) remains incompletely understood. To quantify brain serotonin (5-hydroxytryptamine [5-HT]) turnover in patients with MDD. Patients with depression were studied both untreated and during administration of a selective serotonin reuptake inhibitor (SSRI) in an unblinded study of sequential design. Healthy volunteers were examined on only 1 occasion. Direct internal jugular venous blood sampling was used to directly quantify brain serotonin turnover. The effect of serotonin transporter (5-HTT) genotype on brain serotonin turnover was evaluated and the influence of SSRI therapy on serotonin turnover was investigated. Participants were recruited from the general community following media advertisement. Experimental procedures were performed in the research catheterization laboratory of a major training hospital and medical research institute. Studies were performed in 21 patients fulfilling the DSM-IV and International Statistical Classification of Diseases, 10th Revision diagnostic criteria for MDD and in 40 healthy volunteers. Treatment for patients consisted of SSRI administration for approximately 12 weeks. Brain serotonin turnover before and after SSRI therapy. Brain serotonin turnover was significantly elevated in unmedicated patients with MDD compared with healthy subjects (mean [SD] internal jugular venoarterial 5-hydroxyindoleacetic acid plasma concentration difference, 4.4 [4.3] vs 1.6 [2.4] nmol/L, respectively; P = .003). Analysis of the influence of the 5-HTT genotype in MDD indicated that carriage of the s allele compared with the l allele was associated with greater than a 2-fold increase in brain serotonin turnover (mean [SD] internal jugular venoarterial 5-hydroxyindoleacetic acid plasma concentration difference, 6.5 [4.7] vs 2.7 [2.9] nmol/L, respectively; P = .04). Following SSRI therapy, brain serotonin turnover was substantially reduced (mean [SD] internal jugular venoarterial 5-hydroxyindoleacetic acid plasma concentration difference, 6.0 [4.0] nmol/L prior to treatment vs 2.0 [3.3] nmol/L following therapy; P = .008). Brain serotonin turnover is elevated in unmedicated patients with MDD and is influenced by the 5-HTT genotype. The marked reduction in serotonin turnover following SSRI treatment and the accompanying improvement in symptoms suggest that high brain serotonin turnover may be a biological substrate of MDD.

Special K: testing the potassium link between radioactive rubidium (86Rb) turnover and metabolic rate.

PubMed

Tomlinson, Sean; Mathialagan, Priya D; Maloney, Shane K

2014-04-01

The measurement of (86)Rb turnover recently has been suggested as a useful method for measuring field metabolic rate in small animals. We investigated a proposed mechanism of (86)Rb turnover, its analogy to K(+), by comparing the turnover of (86)Rb in a model insect, the rhinoceros beetle Xylotrupes gideon, fed a diet of plum jam or plum jam enriched with K(+) or Rb(+). The turnover of (86)Rb in the beetles on the K(+) and the Rb(+) diets was higher than that for beetles on the jam diet (F2,311=32.4; P=1.58×10(-13)). We also exposed the beetles to different ambient temperatures to induce differences in metabolic rate ( ) while feeding them the jam and K(+) diets. was higher at higher ambient temperature (Ta) for both jam (F1,11=14.56; P=0.003) and K(+) (F1,8=15.39; P=0.004) dietary groups, and the turnover of (86)Rb was higher at higher Ta for both jam (F1,11=10.80; P=0.007) and K(+) (F1,8=12.34; P=0.008) dietary groups. There was a significant relationship between (86)Rb turnover and for both the jam (F1,11=35.00; P=1.0×10(-3)) and the K(+) (F1,8=64.33; P=4.3×10(-5)) diets, but the relationship differed between the diets (F1,19=14.07; P=0.001), with a higher (86)Rb turnover in beetles on the K(+)-enriched than on the jam diet at all Ta. We conclude that (86)Rb turnover is related to K(+) metabolism, and that this is the mechanism of the relationship between (86)Rb turnover and . Studies relating (86)Rb turnover to should maintain dietary [K] as close as possible to that of natural diets for the most accurate calibrations for free-ranging animals.

Factors affecting turnover intentions among public hospital doctors in a middle-level city in central China.

PubMed

Zhang, Fengfan; Luo, Zhenni; Chen, Ting; Min, Rui; Fang, Pengqian

2017-05-01

Objective The aim of the present study was to explore prominent factors affecting turnover intentions among public hospital doctors in urban areas, particularly in Xiangyang City, Hubei Province, a middle-level city in central China. Methods Questionnaires were used to collect data from 284 public hospital doctors. Pearson's Chi-squared was used to assess whether sociodemographic and other factors were related to the turnover intentions of public hospital doctors. Binary logistic regression was performed to determine the significant factors that influence turnover intentions. Results The analysis revealed that 28.2% of public hospital doctors intended to leave the hospital where they were currently employed. Dissatisfaction with working conditions and hospital management processes, as well as work pressures, were significant factors contributing to the turnover intentions of public hospital doctors. Conclusion Research into turnover intentions indicates that public hospital doctors surveyed in urban China give greater weight to their professional environment and career development rather than salary in their employment decisions. What is known about the topic? Turnover of medical staff is a concern to hospital administrators because it is costly and detrimental to organisational performance and quality of care. Most studies have focused on the effects of individual and organisational factors on nurses' intentions to leave their employment. Income dissatisfaction was one of the determining factors of turnover intentions in previous studies. What does this paper add? The satisfaction of public hospital doctors with regard to income is not a determining factor of turnover intentions. In contrast with findings of previous studies, the doctors in public hospitals in urban China in the present study gave greater weight to their professional environment and career development in their employment decisions. What are the implications for practitioners? The findings suggest that health service managers and policy makers should pay greater attention to the factors affecting public hospital doctors' turnover intentions. This study will be useful for optimising public hospital management and minimising the turnover of doctors in China.

Prolonged Hypocalcemia Following a Single Dose of Denosumab for Diffuse Bone Metastasis of Gastric Cancer after Total Gastrectomy.

PubMed

Iizumi, Sakura; Shimoi, Tatsunori; Nishikawa, Tadaaki; Kitano, Atsuko; Sasada, Shinsuke; Shimomura, Akihiko; Noguchi, Emi; Yunokawa, Mayu; Yonemori, Kan; Shimizu, Chikako; Fujiwara, Yasuhiro; Tamura, Kenji

2017-11-01

Hypocalcemia is a significant adverse effect of denosumab. We herein report a case of prolonged hypocalcemia in a patient with multiple risk factors for hypocalcemia, including gastrectomy, increased bone turnover, and a poor performance status. Hypocalcemia developed after denosumab treatment for diffuse bone metastasis of gastric cancer, despite oral supplementation with vitamin D and calcium. To avoid serious prolonged hypocalcemia, a thorough assessment of the bone calcium metabolism is required before initiating denosumab treatment.

Prolonged Hypocalcemia Following a Single Dose of Denosumab for Diffuse Bone Metastasis of Gastric Cancer after Total Gastrectomy

PubMed Central

Iizumi, Sakura; Shimoi, Tatsunori; Nishikawa, Tadaaki; Kitano, Atsuko; Sasada, Shinsuke; Shimomura, Akihiko; Noguchi, Emi; Yunokawa, Mayu; Yonemori, Kan; Shimizu, Chikako; Fujiwara, Yasuhiro; Tamura, Kenji

2017-01-01

Hypocalcemia is a significant adverse effect of denosumab. We herein report a case of prolonged hypocalcemia in a patient with multiple risk factors for hypocalcemia, including gastrectomy, increased bone turnover, and a poor performance status. Hypocalcemia developed after denosumab treatment for diffuse bone metastasis of gastric cancer, despite oral supplementation with vitamin D and calcium. To avoid serious prolonged hypocalcemia, a thorough assessment of the bone calcium metabolism is required before initiating denosumab treatment. PMID:28943574

Factors associated with the recruitment and retention of social workers in Wales: employer and employee perspectives.

PubMed

Evans, Sherrill; Huxley, Peter

2009-05-01

Despite acute staffing shortages in social work, workforce planning within the UK social care sector is compromised by poor workforce intelligence. This study aimed to inform the evidence base providing new data on recruitment and retention in Wales, examining what personal and organizational characteristics are associated with intentions to leave, and what initiatives or incentives might mediate that effect. A multi-method design facilitated comparisons between two data sources--a census of all 22 Welsh local authority employers about recruitment and retention practices and a survey of all social workers and senior practitioners employed in social services (n = 998; response rate 45.9%) about demography, workforce characteristics, working patterns, morale and plans and reasons for leaving one's job. Vacancy (mean 14.4%) and turnover (mean 15%) rates were statistically significantly higher in children's services than in adult services; vacancy rates were also higher in authorities that offered higher starting salaries. The provision of certain types of traineeship might also be associated with higher vacancy rates but these results should be treated with some caution. There was little evidence that recruitment and retention initiatives were associated with lower vacancy or turnover rates, despite employers' perceptions about their effectiveness. Social workers derived a lot of satisfaction from their work, but more than a quarter wanted to leave their job within 6 months, and almost as many were actively seeking alternative employment. Intention to leave was explained by job and employer satisfaction, and negative feelings about pay. Senior practitioners and staff members with longer lengths of service were less likely to want to leave, even if they were dissatisfied with their job or employer. Job and employer dissatisfaction was associated with retention initiatives related to facilities, good caseload management and home-working, suggesting that dissatisfied staff might remain in employment for longer if these initiatives were in place.

Retention in care and reasons for discontinuation of lifelong antiretroviral therapy in a cohort of Cameroonian pregnant and breastfeeding HIV-positive women initiating 'Option B+' in the South West Region.

PubMed

Atanga, Pascal N; Ndetan, Harrison T; Achidi, Eric A; Meriki, Henry D; Hoelscher, Michael; Kroidl, Arne

2017-02-01

To assess linkage and retention in care along the PMTCT cascade in HIV-positive pregnant and breastfeeding women initiating Option B+ in Cameroon. We prospectively determined uptake of HIV testing and counselling (HTC), uptake of ART and retention in care after Option B+ initiation between October 2013 and December 2014 in pregnant and breastfeeding women from five sites within the Kumba Health District. Retention in care was assessed over at least 12 months follow-up and estimated by Kaplan-Meier analysis. During follow-up, tracing outcomes and reasons for discontinuing treatment were documented. The uptake of HTC of 5813 women with unknown HIV status was 98.5%, 251 (4.4%) were newly diagnosed HIV positive, and ART uptake in women eligible to start Option B+ was 96.8%. We enrolled 268 women initiating lifelong ART in the follow-up. Overall, 65 (24.3%) discontinued treatment, either defined by loss to follow-up (44.6%) or actively stopped treatment (55.8%). Retention in care was 88.0% and 81.1% at 6 and 12 months, respectively. Discontinuation was significantly associated in multivariate analysis with small sites and high staff turnover [aOR 2.5 (95% CI 1.6, 3.9), P < 0.001]. Main reasons for stopping treatment were HIV status denial and stigma (52.8%), religious reasons (25.0%) and lack of transport fare (11.1%). We observed good uptake of HTC, ART and retention in care, which declined over time. Discontinuation of Option B+ was highest at small sites with a high staff turnover. Improved staffing, adequate task shifting and community interventions to track defaulters including reducing stigma and religious beliefs may improve Option B+ retention. © 2016 John Wiley & Sons Ltd.

Telehealth Coaching: Impact on Dietary and Physical Activity Contributions to Bone Health During a Military Deployment.

PubMed

Frank, Laura L; McCarthy, Mary S

2016-05-01

To examine the difference in bone health and body composition via blood biomarkers, bone mineral density, anthropometrics and dietary intake following deployment to Afghanistan among soldiers randomized to receive telehealth coaching promoting nutrition and exercise. This was a prospective, longitudinal, cluster-randomized, controlled trial with repeated measures in 234 soldiers. Measures included heel bone scan for bone mineral density, blood biomarkers for bone formation, resorption, and turnover, body composition via Futrex, resting metabolic rate via MedGem, physical activity using the Baecke Habitual Physical Activity Questionnaire, and dietary intake obtained from the Block Food Frequency Questionnaire. There were significant increases in body fat (p = 0.00035), osteocalcin (0.0152), and sports index (p = 0.0152) for the telehealth group. No other statistically significant differences were observed between groups. Vitamin D intake among soldiers was ≤ 35% of the suggested Dietary Reference Intakes for age. A 9-month deployment to Afghanistan increased body fat, bone turnover, and physical activity among soldiers randomized to receive telehealth strategies to build bone with nutrition and exercise. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Charge separation related to photocatalytic H 2 production from a Ru–apoflavodoxin–Ni biohybrid

DOE PAGES

Soltau, Sarah R.; Niklas, Jens; Dahlberg, Peter D.; ...

2016-12-27

The direct creation of a fuel from sunlight and water via photochemical energy conversion provides a sustainable method for producing a clean source of energy. Here we report the preparation of a solar fuel biohybrid that embeds a nickel diphosphine hydrogen evolution catalyst into the cofactor binding pocket of the electron shuttle protein, flavodoxin (Fld). The system is made photocatalytic by linking a cysteine residue in Fld to a ruthenium photosensitizer. Importantly, the protein environment enables the otherwise insoluble Ni catalyst to perform photocatalysis in aqueous solution over a pH range of 3.5–12.0, with optimal turnover frequency 410 ± 30more » h –1 and turnover number 620 ± 80 mol H 2/mol hybrid observed at pH 6.2. For the first time, a reversible light-induced charge-separated state involving a Ni(I) intermediate was directly monitored by electron paramagnetic resonance spectroscopy. As a result, transient optical measurements reflect two conformational states, with a Ni(I) state formed in ~1.6 or ~185 μs that persists for several milliseconds as a long-lived charge-separated state facilitated by the protein matrix.« less

Hard X-ray quiescent emission in magnetars via resonant Compton upscattering

NASA Astrophysics Data System (ADS)

Baring, M. G.; Wadiasingh, Z.; Gonthier, P. L.; Harding, A. K.

2017-12-01

Non-thermal quiescent X-ray emission extending between 10 keV and around 150 keV has been seen in about 10 magnetars by RXTE, INTEGRAL, Suzaku, NuSTAR and Fermi-GBM. For inner magnetospheric models of such hard X-ray signals, inverse Compton scattering is anticipated to be the most efficient process for generating the continuum radiation, because the scattering cross section is resonant at the cyclotron frequency. We present hard X-ray upscattering spectra for uncooled monoenergetic relativistic electrons injected in inner regions of pulsar magnetospheres. These model spectra are integrated over bundles of closed field lines and obtained for different observing perspectives. The spectral turnover energies are critically dependent on the observer viewing angles and electron Lorentz factor. We find that electrons with energies less than around 15 MeV will emit most of their radiation below 250 keV, consistent with the turnovers inferred in magnetar hard X-ray tails. Electrons of higher energy still emit most of the radiation below around 1 MeV, except for quasi-equatorial emission locales for select pulse phases. Our spectral computations use a new state-of-the-art, spin-dependent formalism for the QED Compton scattering cross section in strong magnetic fields.

HIghZ: A search for HI absorption in high-redshift radio galaxies

NASA Astrophysics Data System (ADS)

Allison, J.; Callingham, J.; Sadler, E.; Wayth, R.; Curran, S.; Mahoney, E.

2017-01-01

We will use the unique low-frequency spectral capability of the MWA to carry out a pilot survey for neutral gas in the interstellar medium of the most distant (z>5) radio galaxies in the Universe. Through detection of the HI 21-cm line in absorption we aim to place stringent lower limits on the source redshift, confirming its location in the early Universe. Our sample makes use of the excellent wide-band spectral information available from the recently completed MWA GLEAM survey, from which we have selected a sample of ultra-steep peaked-spectrum radio sources that have a spectral turnover below 300 MHz. These sources should be ideal candidates for high-redshift compact radio galaxies since they have (a) spectral peaks that turnover below 1GHz and (b) very steep (alpha < -1.0) spectral indices that are consistent with the high density environments expected for radio galaxies in the early Universe. Using the MWA, we aim to verify this hypothesis through the detection of significant column densities of cold HI. This pathfinder project will provide important technical information that will inform future absorption surveys both with the MWA and, ultimately, the SKA-LOW telescope.

In situ fabricated platinum—poly(vinyl alcohol) nanocomposite thin film: a highly reusable ‘dip catalyst’ for hydrogenation

NASA Astrophysics Data System (ADS)

Divya Madhuri, U.; Kesava Rao, V.; Hariprasad, E.; Radhakrishnan, T. P.

2016-04-01

A simple protocol for the in situ generation of platinum nanoparticles in a poly(vinyl alcohol) (PVA) thin film is developed. Chloroplatinic acid as well as potassium platinum(II) chloride are used as precursors and the film is fabricated by spin coating followed by mild thermal annealing. The chemical process occurring inside the film, wherein the polymer itself acts as the reducing agent, is explored through different spectroscopy and microscopy techniques. The Pt-PVA film, <100 nm thick and containing ˜1 nm size Pt nanoparticles, is shown to be a highly efficient catalyst for the reduction of methylene blue using sodium borohydride. The ease of retrieval and reuse of the thin film is highlighted by the term ‘dip catalyst’. The reaction yield, kinetics and rate are reproducible through several reuses of the same catalyst film. Turnover number (TON = number of mols of product/number of mols of catalyst) and turnover frequency (TOF = TON/reaction time) are significantly higher than those reported earlier for this reaction using metal nanocatalysts. Utility of Pt-PVA film as an efficient catalyst for other hydrogenation reactions is demonstrated.

Turnover intentions in a call center: The role of emotional dissonance, job resources, and job satisfaction.

PubMed

Zito, Margherita; Emanuel, Federica; Molino, Monica; Cortese, Claudio Giovanni; Ghislieri, Chiara; Colombo, Lara

2018-01-01

Turnover intentions refer to employees' intent to leave the organization and, within call centers, it can be influenced by factors such as relational variables or the perception of the quality of working life, which can be affected by emotional dissonance. This specific job demand to express emotions not felt is peculiar in call centers, and can influence job satisfaction and turnover intentions, a crucial problem among these working contexts. This study aims to detect, within the theoretical framework of the Job Demands-Resources Model, the role of emotional dissonance (job demand), and two resources, job autonomy and supervisors' support, in the perception of job satisfaction and turnover intentions among an Italian call center. The study involved 318 call center agents of an Italian Telecommunication Company. Data analysis first performed descriptive statistics through SPSS 22. A path analysis was then performed through LISREL 8.72 and tested both direct and indirect effects. Results suggest the role of resources in fostering job satisfaction and in decreasing turnover intentions. Emotional dissonance reveals a negative relation with job satisfaction and a positive relation with turnover. Moreover, job satisfaction is negatively related with turnover and mediates the relationship between job resources and turnover. This study contributes to extend the knowledge about the variables influencing turnover intentions, a crucial problem among call centers. Moreover, the study identifies theoretical considerations and practical implications to promote well-being among call center employees. To foster job satisfaction and reduce turnover intentions, in fact, it is important to make resources available, but also to offer specific training programs to make employees and supervisors aware about the consequences of emotional dissonance.

Global covariation of carbon turnover times with climate in terrestrial ecosystems.

PubMed

Carvalhais, Nuno; Forkel, Matthias; Khomik, Myroslava; Bellarby, Jessica; Jung, Martin; Migliavacca, Mirco; Mu, Mingquan; Saatchi, Sassan; Santoro, Maurizio; Thurner, Martin; Weber, Ulrich; Ahrens, Bernhard; Beer, Christian; Cescatti, Alessandro; Randerson, James T; Reichstein, Markus

2014-10-09

The response of the terrestrial carbon cycle to climate change is among the largest uncertainties affecting future climate change projections. The feedback between the terrestrial carbon cycle and climate is partly determined by changes in the turnover time of carbon in land ecosystems, which in turn is an ecosystem property that emerges from the interplay between climate, soil and vegetation type. Here we present a global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes. We find that the overall mean global carbon turnover time is 23(+7)(-4) years (95 per cent confidence interval). On average, carbon resides in the vegetation and soil near the Equator for a shorter time than at latitudes north of 75° north (mean turnover times of 15 and 255 years, respectively). We identify a clear dependence of the turnover time on temperature, as expected from our present understanding of temperature controls on ecosystem dynamics. Surprisingly, our analysis also reveals a similarly strong association between turnover time and precipitation. Moreover, we find that the ecosystem carbon turnover times simulated by state-of-the-art coupled climate/carbon-cycle models vary widely and that numerical simulations, on average, tend to underestimate the global carbon turnover time by 36 per cent. The models show stronger spatial relationships with temperature than do observation-based estimates, but generally do not reproduce the strong relationships with precipitation and predict faster carbon turnover in many semi-arid regions. Our findings suggest that future climate/carbon-cycle feedbacks may depend more strongly on changes in the hydrological cycle than is expected at present and is considered in Earth system models.

Turnover intentions in a call center: The role of emotional dissonance, job resources, and job satisfaction

PubMed Central

Zito, Margherita; Molino, Monica; Cortese, Claudio Giovanni; Ghislieri, Chiara; Colombo, Lara

2018-01-01

Background Turnover intentions refer to employees’ intent to leave the organization and, within call centers, it can be influenced by factors such as relational variables or the perception of the quality of working life, which can be affected by emotional dissonance. This specific job demand to express emotions not felt is peculiar in call centers, and can influence job satisfaction and turnover intentions, a crucial problem among these working contexts. This study aims to detect, within the theoretical framework of the Job Demands-Resources Model, the role of emotional dissonance (job demand), and two resources, job autonomy and supervisors’ support, in the perception of job satisfaction and turnover intentions among an Italian call center. Method The study involved 318 call center agents of an Italian Telecommunication Company. Data analysis first performed descriptive statistics through SPSS 22. A path analysis was then performed through LISREL 8.72 and tested both direct and indirect effects. Results Results suggest the role of resources in fostering job satisfaction and in decreasing turnover intentions. Emotional dissonance reveals a negative relation with job satisfaction and a positive relation with turnover. Moreover, job satisfaction is negatively related with turnover and mediates the relationship between job resources and turnover. Conclusion This study contributes to extend the knowledge about the variables influencing turnover intentions, a crucial problem among call centers. Moreover, the study identifies theoretical considerations and practical implications to promote well-being among call center employees. To foster job satisfaction and reduce turnover intentions, in fact, it is important to make resources available, but also to offer specific training programs to make employees and supervisors aware about the consequences of emotional dissonance. PMID:29401507

Use of operating room information system data to predict the impact of reducing turnover times on staffing costs.

PubMed

Dexter, Franklin; Abouleish, Amr E; Epstein, Richard H; Whitten, Charles W; Lubarsky, David A

2003-10-01

Potential benefits to reducing turnover times are both quantitative (e.g., complete more cases and reduce staffing costs) and qualitative (e.g., improve professional satisfaction). Analyses have shown the quantitative arguments to be unsound except for reducing staffing costs. We describe a methodology by which each surgical suite can use its own numbers to calculate its individual potential reduction in staffing costs from reducing its turnover times. Calculations estimate optimal allocated operating room (OR) time (based on maximizing OR efficiency) before and after reducing the maximum and average turnover times. At four academic tertiary hospitals, reductions in average turnover times of 3 to 9 min would result in 0.8% to 1.8% reductions in staffing cost. Reductions in average turnover times of 10 to 19 min would result in 2.5% to 4.0% reductions in staffing costs. These reductions in staffing cost are achieved predominantly by reducing allocated OR time, not by reducing the hours that staff work late. Heads of anesthesiology groups often serve on OR committees that are fixated on turnover times. Rather than having to argue based on scientific studies, this methodology provides the ability to show the specific quantitative effects (small decreases in staffing costs and allocated OR time) of reducing turnover time using a surgical suite's own data. Many anesthesiologists work at hospitals where surgeons and/or operating room (OR) committees focus repeatedly on turnover time reduction. We developed a methodology by which the reductions in staffing cost as a result of turnover time reduction can be calculated for each facility using its own data. Staffing cost reductions are generally very small and would be achieved predominantly by reducing allocated OR time to the surgeons.

Exposure to negative acts and risk of turnover: a study of a register-based outcome among employees in three occupational groups.

PubMed

Clausen, Thomas; Hansen, Jørgen V; Hogh, Annie; Garde, Anne Helene; Persson, Roger; Conway, Paul Maurice; Grynderup, Matias; Hansen, Åse Marie; Rugulies, Reiner

2016-11-01

To investigate whether self-reported exposure to negative acts in the workplace (bullying and threats of violence) predicted turnover in three occupational groups (human service and sales workers, office workers and manual workers). Survey data on 2766 respondents were combined with data from a national labour force register to assess turnover. Mixed effects logistic regression analysis was used to examine the association between self-reported exposure to negative acts at baseline and risk of turnover after a 1-year follow-up. We found no significant associations between exposure to negative acts (bullying and threats of violence) and risk of turnover. When participants were stratified by occupational group and analyses were adjusted for age, gender, tenure and psychosocial working conditions, we found that exposure to bullying predicted risk of turnover in office workers (OR 2.03, 95 % CI 1.05-3.90), but neither in human service and sales workers, nor in manual workers. The association in office workers lost statistical significance when additionally adjusted for depressive symptoms (OR 1.77, 95 % CI 0.90-3.49). However, in a sensitivity analysis in which we used a 2-year (instead of a 1-year) follow-up period the association between bullying and turnover remained statistically significant in office workers even after adjusting for depressive symptoms (OR 2.10, 95 % CI 1.17-3.76). We found no statistically significant associations between threats of violence and risk of turnover in the stratified analyses. Exposure to bullying predicted risk of turnover among office workers but not among human service and sales workers and among manual workers. Threats of violence were not associated with turnover in any occupational group.

Person-organization fit and turnover intention: exploring the mediating effect of work engagement and the moderating effect of demand-ability fit.

PubMed

Peng, Jui-Chen; Lee, Yin-Ling; Tseng, Mei-Man

2014-03-01

Person-organization (P-O) fit is an important influencing factor on the intentions and attitudes of hospital nurses. The authors used a motivation-mechanism approach to conceptualize work engagement as a mediator and demand-ability (D-A) fit as a moderator to elicit the role of P-O fit in the turnover intention of nurses. This article explores whether the work engagement of nurses mediates the relationship between P-O fit and turnover intention and examines whether D-A fit moderates this relationship. The sample comprised 349 nurses working for two regional hospitals in Yilan County, Taiwan. Linear regression modeling analysis was conducted to test the proposed hypotheses. Results indicate that P-O fit has a negative effect on participant turnover intention. In addition, the work engagement of participants was found to mediate the impact of P-O fit on turnover intention. A new significant interactive relationship was discovered such that high D-A fit strengthened the negative relationship between P-O fit and turnover intention. The work engagement of professional nurses has attracted increasing attention in the literature on fit, particularly with regard to the linkage between P-O and fit-turnover intention. This study enhances the understanding of the function of P-O fit by considering perceived D-A fit. Nurse turnover is the main reason for the current shortage of nurses in Taiwan. Therefore, if the cognitive values of nurses and the organizational culture fit with hospital value systems, common values may facilitate a higher degree of nurse work engagement and, in turn, decrease turnover intention. In addition, recruiting employees with high D-A fit may help hospitals enhance the negative relationship between P-O fit and nurse turnover intention.

Nursing home spending, staffing, and turnover.

PubMed

Kash, Bita A; Castle, Nicholas G; Phillips, Charles D

2007-01-01

Recent work on nursing home staffing and turnover has stressed the importance of ownership and resources. However, few studies have examined spending behaviors, which might also influence staffing levels and staff turnover rates. This study investigates whether spending behaviors measured by financial ratios are associated with staffing levels and staff turnover in nursing homes. We analyzed cross-sectional data from 1,014 Texas homes. Data were from the 2002 Texas Nursing Facility Medicaid Cost Report and the 2003 Area Resource File. First, we examined differences in financial ratios by ownership type. Next, the effect of 10 financial ratios on staffing levels and turnover rates for registered nurses, licensed vocational nurses, and certified nursing assistants was examined using robust regression models. Descriptive data indicated that expense ratios related to resident care activities and staff development were significantly higher among not-for-profit than for-profit homes. Higher profits were associated with lower staffing levels, but not higher turnover rates. Administrative expenses (a measure of management capacity) had a negative impact both on staffing levels and staff turnover for licensed vocational nurses and certified nursing assistants, but they did not affect registered nurse staffing. Employee benefit expenses exhibited a positive impact on registered nurse and licensed vocational nurse staffing levels. The addition of information on financial ratios to models predicting staffing indicators reduced the effect of ownership on these indicators. Solutions to the staffing and turnover problem should focus on more effective management practices. Certain levels of administrative and staff benefit expenses may be necessary to improve professional staff recruitment and reduce both staffing and turnover costs. Differences in these financial ratios may partially explain the role played by ownership in determining staffing levels and turnover.

Turnover of Grassland Roots in Mountain Ecosystems Revealed by Their Radiocarbon Signature: Role of Temperature and Management

PubMed Central

Leifeld, Jens; Meyer, Stefanie; Budge, Karen; Sebastia, Maria Teresa; Zimmermann, Michael; Fuhrer, Juerg

2015-01-01

Root turnover is an important carbon flux component in grassland ecosystems because it replenishes substantial parts of carbon lost from soil via heterotrophic respiration and leaching. Among the various methods to estimate root turnover, the root’s radiocarbon signature has rarely been applied to grassland soils previously, although the value of this approach is known from studies in forest soils. In this paper, we utilize the root’s radiocarbon signatures, at 25 plots, in mountain grasslands of the montane to alpine zone of Europe. We place the results in context of a global data base on root turnover and discuss driving factors. Root turnover rates were similar to those of a subsample of the global data, comprising a similar temperature range, but measured with different approaches, indicating that the radiocarbon method gives reliable, plausible and comparable results. Root turnover rates (0.06–1.0 y-1) scaled significantly and exponentially with mean annual temperatures. Root turnover rates indicated no trend with soil depth. The temperature sensitivity was significantly higher in mountain grassland, compared to the global data set, suggesting additional factors influencing root turnover. Information on management intensity from the 25 plots reveals that root turnover may be accelerated under intensive and moderate management compared to low intensity or semi-natural conditions. Because management intensity, in the studied ecosystems, co-varied with temperature, estimates on root turnover, based on mean annual temperature alone, may be biased. A greater recognition of management as a driver for root dynamics is warranted when effects of climatic change on belowground carbon dynamics are studied in mountain grasslands. PMID:25734640

Methyl group turnover on methyl-accepting chemotaxis proteins during chemotaxis by Bacillus subtilis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thoelke, M.S.; Casper, J.M.; Ordal, G.W.

1990-02-05

The addition of attractant to Bacillus subtilis briefly exposed to radioactive methionine causes an increase of labeling of the methyl-accepting chemotaxis proteins. The addition of attractant to cells radiolabeled for longer times shows no change in the extent of methylation. Therefore, the increase in labeling for the briefly labeled cells is due to an increased turnover of methyl groups caused by attractant. All amino acids gave enhanced turnover. This turnover lasted for a prolonged time, probably spanning the period of smooth swimming caused by the attractant addition. Repellent did not affect the turnover when added alone or simultaneously with attractant.more » Thus, for amino acid attractants, the turnover is probably the excitatory signal, which is seen to extend long into or throughout the adaptation period, not just at the start of it.« less

The right friends in the right places: Understanding network structure as a predictor of voluntary turnover.

PubMed

Ballinger, Gary A; Cross, Rob; Holtom, Brooks C

2016-04-01

Research examining the relationship between social networks and employee retention has focused almost exclusively on the number of direct links and generally found that having more ties decreases the likelihood of turnover. The present research moves beyond simple measures of network centrality to investigate the relationship between 2 additional, and theoretically distinct, facets of social capital and voluntary turnover. In 2 organizations, we found consistent evidence of a negative relationship between reputation, as measured by relationships with highly sought-out others (incoming eigenvector centrality) and voluntary turnover. Further, we found that the negative relationship between brokerage (structural holes) and turnover is significant, but only for higher-level employees. The theoretical and practical implications of expanding the suite of social capital measures to understand voluntary turnover are discussed. (c) 2016 APA, all rights reserved).

Unit-level voluntary turnover rates and customer service quality: implications of group cohesiveness, newcomer concentration, and size.

PubMed

Hausknecht, John P; Trevor, Charlie O; Howard, Michael J

2009-07-01

Despite substantial growth in the service industry and emerging work on turnover consequences, little research examines how unit-level turnover rates affect essential customer-related outcomes. The authors propose an operational disruption framework to explain why voluntary turnover impairs customers' service quality perceptions. On the basis of a sample of 75 work units and data from 5,631 employee surveys, 59,602 customer surveys, and organizational records, results indicate that unit-level voluntary turnover rates are negatively related to service quality perceptions. The authors also examine potential boundary conditions related to the disruption framework. Of 3 moderators studied (group cohesiveness, group size, and newcomer concentration), results show that turnover's negative effects on service quality are more pronounced in larger units and in those with a greater concentration of newcomers.

Age-related changes in bone turnover in men.

PubMed

Fatayerji, D; Eastell, R

1999-07-01

Biochemical markers of bone turnover can be used to study the pathophysiology of osteoporosis. So far there have been few such studies in men. The aims of this study were to determine the effect of aging on bone turnover and to identify which hormones might regulate bone turnover in men. We studied 178 healthy Caucasian men, ages 20-79 years (30 per decade). The data for the effect of age on bone turnover was best fit by a quadratic function (nadirs at age 56, 57, 53, 39, and 58 years for intact propeptide of type I procollagen, osteocalcin, bone alkaline phosphatase, free deoxypyridinoline, and cross-linked N-telopeptides of type I collagen, respectively). For most markers, bone turnover tended to be highest in the third decade, lowest in the fifth and sixth decade, with a small increase in some markers in the eighth decade. Insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3, dehydroepiandrosterone sulfate, testosterone, estradiol, and free androgen index all decreased significantly with age (54, 17, 76, 26, 33, and 57%, respectively), while sex hormone binding globulin and parathyroid hormone increased significantly with age (62% and 43%). IGF-I and sex hormones were positively correlated with bone turnover, and this association was stronger in young men than older men. In conclusion, increased IGF-I and sex hormones may be associated with increased bone turnover in young men, with less influence on bone turnover in older men.

The relationship between job satisfaction, work stress, work-family conflict, and turnover intention among physicians in Guangdong, China: a cross-sectional study.

PubMed

Lu, Yong; Hu, Xiao-Min; Huang, Xiao-Liang; Zhuang, Xiao-Dong; Guo, Pi; Feng, Li-Fen; Hu, Wei; Chen, Long; Zou, Huachun; Hao, Yuan-Tao

2017-05-12

To investigate the relationship between job satisfaction, work stress, work-family conflict and turnover intention, and explore factors associated with turnover intention, among physicians in Guangdong Province, China. From August to October 2013, physicians completed questionnaires and scales with regard to their job satisfaction, work stress, work-family conflict, and turnover intention. Binary logistic regression and structural equation modelling (SEM) were used in data analysis. A total of 3963 physicians were approached, with 3563 completing the questionnaire. The mean score of the overall perception of turnover intention of physicians who worked in Guangdong was 2.71 on a scale ranging from 1 to 6. Hours worked per week, working in an urban/rural area, type of institution, and age significantly impacted on turnover intention. Turnover intention was directly and negatively related to job satisfaction, and it was directly, indirectly and positively related to work stress and work-family conflict. Job satisfaction, work stress, work-family conflict, hours worked per week, working in an urban/rural area, types of institution and age are influencing factors of turnover intention. Reducing working hours, raising salary, providing more opportunities for career development and training, supporting and encouraging physicians by senior managers could potentially contribute to the reduction in turnover intention. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Impact of euthanasia rates, euthanasia practices, and human resource practices on employee turnover in animal shelters.

PubMed

Rogelberg, Steven G; Reeve, Charlie L; Spitzmüller, Christiane; DiGiacomo, Natalie; Clark, Olga L; Teeter, Lisa; Walker, Alan G; Starling, Paula G; Carter, Nathan T

2007-03-01

To examine the effects of euthanasia rates, euthanasia practices, and human resource practices on the turnover rate among employees with euthanasia responsibilities at animal shelters. Cross-sectional original study. 36 shelters across the United States that employed at least 5 full-time employees and performed euthanasia on site. By mail, 1 survey was sent to each shelter. Surveys were completed by a senior member of management and were returned by mail. Questions assessed characteristics (eg, euthanasia rates) and practices of the animal shelter, along with employee turnover rates. By use of correlation coefficients and stepwise regression analyses, key predictors of turnover rates among employees with euthanasia responsibilities were investigated. Employee turnover rates were positively related to euthanasia rate. Practices that were associated with decreased turnover rates included provision of a designated euthanasia room, exclusion of other live animals from vicinity during euthanasia, and removal of euthanized animals from a room prior to entry of another animal to be euthanized. Making decisions regarding euthanasia of animals on the basis of factors other than behavior and health reasons was related to increased personnel turnover. With regard to human resources practices, shelters that used a systematic personnel selection procedure (eg, standardized testing) had comparatively lower employee turnover. Data obtained may suggest several specific avenues that can be pursued to mitigate turnover among employees with euthanasia responsibilities at animal shelters and animal control or veterinary medical organizations.

The Influence of Personal Factors and Perceived Work Experiences on Employee Turnover and Absenteeism.

DTIC Science & Technology

1979-11-01

FExperiences onl Employee Turnover and Absenteeism Daniel G. Spencer School of Business University of Kansas Richard M. Steers Graduiate School of...Idenify by block nomber) Turnover Education Organizational dependability Absenteeism Group Attitudes Personal importance Tenure Met expectations Age...perceived work experiences on employee turnover and absenteeism among a sample of 200 clerical and service workers in a Major hospital. It was found that

The phase model of burnout and employee turnover.

PubMed

Goodman, Eric A; Boss, R Wayne

2002-01-01

This study explores the phase model of burnout and investigates its relationship to actual turnover in a hospital. The results indicate that employees who turnover have significantly higher burnout phase scores that those who stay in the organization. A further comparison of voluntary and involuntary turnover demonstrates that there is no significant differences on burnout phase scores. The findings lend support to the usefulness of the phase model of burnout.

How important is embeddedness in predicting Australian speech-language pathologists' intentions to leave their jobs and the profession?

PubMed

Heritage, Brody; Quail, Michelle; Cocks, Naomi

2018-03-05

This study explored the predictors of the outcomes of turnover and occupation attrition intentions for speech-language pathologists. The researchers examined the mediating effects of job satisfaction and strain on the relationship between stress and the latter outcomes. Additionally, the researchers examined the importance of embeddedness in predicting turnover intentions after accounting for stress, strain and job satisfaction. An online questionnaire was used to explore turnover and attrition intentions in 293 Australian speech-language pathologists. Job satisfaction contributed to a significant indirect effect on the stress and turnover intention relationship, however strain did not. There was a significant direct effect between stress and turnover intention after accounting for covariates. Embeddedness and the perceived availability of alternative jobs were also found to be significant predictors of turnover intentions. The mediating model used to predict turnover intentions also predicted occupation attrition intentions. The effect of stress on occupation attrition intentions was indirect in nature, the direct effect negated by mediating variables. Qualitative data provided complementary evidence to the quantitative model. The findings indicate that the proposed parsimonious model adequately captures predictors of speech-language pathologists' turnover and occupation attrition intentions. Workplaces and the profession may wish to consider these retention factors.

Concurrent and lagged effects of registered nurse turnover and staffing on unit-acquired pressure ulcers.

PubMed

Park, Shin Hye; Boyle, Diane K; Bergquist-Beringer, Sandra; Staggs, Vincent S; Dunton, Nancy E

2014-08-01

We examined the concurrent and lagged effects of registered nurse (RN) turnover on unit-acquired pressure ulcer rates and whether RN staffing mediated the effects. Quarterly unit-level data were obtained from the National Database of Nursing Quality Indicators for 2008 to 2010. A total of 10,935 unit-quarter observations (2,294 units, 465 hospitals) were analyzed. This longitudinal study used multilevel regressions and tested time-lagged effects of study variables on outcomes. The lagged effect of RN turnover on unit-acquired pressure ulcers was significant, while there was no concurrent effect. For every 10 percentage-point increase in RN turnover in a quarter, the odds of a patient having a pressure ulcer increased by 4 percent in the next quarter. Higher RN turnover in a quarter was associated with lower RN staffing in the current and subsequent quarters. Higher RN staffing was associated with lower pressure ulcer rates, but it did not mediate the relationship between turnover and pressure ulcers. We suggest that RN turnover is an important factor that affects pressure ulcer rates and RN staffing needed for high-quality patient care. Given the high RN turnover rates, hospital and nursing administrators should prepare for its negative effect on patient outcomes. © Health Research and Educational Trust.

Concurrent and Lagged Effects of Registered Nurse Turnover and Staffing on Unit-Acquired Pressure Ulcers

PubMed Central

Park, Shin Hye; Boyle, Diane K; Bergquist-Beringer, Sandra; Staggs, Vincent S; Dunton, Nancy E

2014-01-01

Objective We examined the concurrent and lagged effects of registered nurse (RN) turnover on unit-acquired pressure ulcer rates and whether RN staffing mediated the effects. Data Sources/Setting Quarterly unit-level data were obtained from the National Database of Nursing Quality Indicators for 2008 to 2010. A total of 10,935 unit-quarter observations (2,294 units, 465 hospitals) were analyzed. Methods This longitudinal study used multilevel regressions and tested time-lagged effects of study variables on outcomes. Findings The lagged effect of RN turnover on unit-acquired pressure ulcers was significant, while there was no concurrent effect. For every 10 percentage-point increase in RN turnover in a quarter, the odds of a patient having a pressure ulcer increased by 4 percent in the next quarter. Higher RN turnover in a quarter was associated with lower RN staffing in the current and subsequent quarters. Higher RN staffing was associated with lower pressure ulcer rates, but it did not mediate the relationship between turnover and pressure ulcers. Conclusions We suggest that RN turnover is an important factor that affects pressure ulcer rates and RN staffing needed for high-quality patient care. Given the high RN turnover rates, hospital and nursing administrators should prepare for its negative effect on patient outcomes. PMID:24476194

Genetically programmed chiral organoborane synthesis

NASA Astrophysics Data System (ADS)

Kan, S. B. Jennifer; Huang, Xiongyi; Gumulya, Yosephine; Chen, Kai; Arnold, Frances H.

2017-12-01

Recent advances in enzyme engineering and design have expanded nature’s catalytic repertoire to functions that are new to biology. However, only a subset of these engineered enzymes can function in living systems. Finding enzymatic pathways that form chemical bonds that are not found in biology is particularly difficult in the cellular environment, as this depends on the discovery not only of new enzyme activities, but also of reagents that are both sufficiently reactive for the desired transformation and stable in vivo. Here we report the discovery, evolution and generalization of a fully genetically encoded platform for producing chiral organoboranes in bacteria. Escherichia coli cells harbouring wild-type cytochrome c from Rhodothermus marinus (Rma cyt c) were found to form carbon-boron bonds in the presence of borane-Lewis base complexes, through carbene insertion into boron-hydrogen bonds. Directed evolution of Rma cyt c in the bacterial catalyst provided access to 16 novel chiral organoboranes. The catalyst is suitable for gram-scale biosynthesis, providing up to 15,300 turnovers, a turnover frequency of 6,100 h-1, a 99:1 enantiomeric ratio and 100% chemoselectivity. The enantiopreference of the biocatalyst could also be tuned to provide either enantiomer of the organoborane products. Evolved in the context of whole-cell catalysts, the proteins were more active in the whole-cell system than in purified forms. This study establishes a DNA-encoded and readily engineered bacterial platform for borylation; engineering can be accomplished at a pace that rivals the development of chemical synthetic methods, with the ability to achieve turnovers that are two orders of magnitude (over 400-fold) greater than those of known chiral catalysts for the same class of transformation. This tunable method for manipulating boron in cells could expand the scope of boron chemistry in living systems.

Newly graduated nurses' occupational commitment and its associations with professional competence and work-related factors.

PubMed

Numminen, Olivia; Leino-Kilpi, Helena; Isoaho, Hannu; Meretoja, Riitta

2016-01-01

To explore newly graduated nurses' occupational commitment and its associations with their self-assessed professional competence and other work-related factors. As a factor affecting nurse turnover, newly graduated nurses' occupational commitment and its associations with work-related factors needs exploring to retain adequate workforce. Nurses' commitment has mainly been studied as organisational commitment, but newly graduated nurses' occupational commitment and its association with work-related factors needs further studying. This study used descriptive, cross-sectional, correlation design. A convenience sample of 318 newly graduated nurses in Finland participated responding to an electronic questionnaire. Statistical software, NCSS version 9, was used in data analysis. Frequencies, percentages, ranges, means and standard deviations summarised the data. Multivariate Analyses of Variance estimated associations between occupational commitment and work-related variables. IBM SPSS Amos version 22 estimated the model fit of Occupational Commitment Scale and Nurse Competence Scale. Newly graduated nurses' occupational commitment was good, affective commitment reaching the highest mean score. There was a significant difference between the nurse groups in favour of nurses at higher competence levels in all subscales except in limited alternatives occupational commitment. Multivariate analyses revealed significant associations between subscales of commitment and competence, turnover intentions, job satisfaction, earlier professional education and work sector, competence counting only through affective dimension. The association between occupational commitment and low turnover intentions and satisfaction with nursing occupation was strong. Higher general competence indicated higher overall occupational commitment. Managers' recognition of the influence of all dimensions of occupational commitment in newly graduated nurses' professional development is important. Follow-up studies of newly graduated nurses' commitment, its relationship with quality care, managers' role in enhancing commitment and evaluation of the impact of interventions on improving commitment need further studying. © 2015 John Wiley & Sons Ltd.

Characterization of Photochemical Processes for H2 Production by CdS Nanorod-[FeFe] Hydrogenase Complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, K. A.; Wilker, M. B.; Boehm, M.

2012-03-28

We have developed complexes of CdS nanorods capped with 3-mercaptopropionic acid (MPA) and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) that photocatalyze reduction of H{sup +} to H{sub 2} at a CaI turnover frequency of 380-900 s{sup -1} and photon conversion efficiencies of up to 20% under illumination at 405 nm. In this paper, we focus on the compositional and mechanistic aspects of CdS:CaI complexes that control the photochemical conversion of solar energy into H{sub 2}. Self-assembly of CdS with CaI was driven by electrostatics, demonstrated as the inhibition of ferredoxin-mediated H{sub 2} evolution by CaI. Production of H{sub 2} by CdS:CaImore » was observed only under illumination and only in the presence of a sacrificial donor. We explored the effects of the CdS:CaI molar ratio, sacrificial donor concentration, and light intensity on photocatalytic H{sub 2} production, which were interpreted on the basis of contributions to electron transfer, hole transfer, or rate of photon absorption, respectively. Each parameter was found to have pronounced effects on the CdS:CaI photocatalytic activity. Specifically, we found that under 405 nm light at an intensity equivalent to total AM 1.5 solar flux, H{sub 2} production was limited by the rate of photon absorption ({approx}1 ms{sup -1}) and not by the turnover of CaI. Complexes were capable of H{sub 2} production for up to 4 h with a total turnover number of 106 before photocatalytic activity was lost. This loss correlated with inactivation of CaI, resulting from the photo-oxidation of the CdS capping ligand MPA.« less

[Influence of hormonal contraceptives on indices of zinc homeostasis and bone remodeling in young adult women].

PubMed

Simões, Tania Mara Rodrigues; Zapata, Carmiña Lucía Vargas; Donangelo, Carmen Marino

2015-09-01

To investigate the influence of the use of oral hormonal contraceptive agents (OCA) on the biochemical indices related to metabolic zinc utilization and distribution, and to bone turnover in young adult women. Cross-sectional study. Blood and urine samples from non-users (-OCA; control; n=69) and users of hormonal contraceptives for at least 3 months (+OCA; n=62) were collected under controlled conditions. Indices of zinc homeostasis and of bone turnover were analyzed in serum or plasma (total, albumin-bound and α2-macroglobulin-bound zinc, albumin and total and bone alkaline phosphatase activity), in erythrocytes (zinc and metallothionein) and in urine (zinc, calcium and hydroxyproline). The habitual zinc and calcium intakes were evaluated by a food frequency questionnaire. Dietary zinc intake was similar in both groups and on average above recommended values, whereas calcium intake was similarly sub-adequate in +OCA and -OCA. Compared to controls, +OCA had lower concentrations of total and α2-macroglobulin-bound zinc (11 and 28.5%, respectively, p<0.001), serum albumin (13%, p<0.01), total and bone-specific alkaline phosphatase activity (13 and 18%, respectively, p<0.05), erythrocyte metallothionein (13%, p<0.01), and, urinary zinc (34%, p<0.05). OCA use decreases serum zinc, alters zinc distribution in major serum fractions with possible effects on tissue uptake, enhances zinc retention in the body and decreases bone turnover. Prolonged OCA use may lead to lower peak bone mass and/or to impaired bone mass maintenance in young women, particularly in those with marginal calcium intake. The observed OCA effects were more evident in women younger than 25 years and in nulliparous women, deserving special attention in future studies.

BONE TURNOVER IN OSTEOPOROTIC WOMEN DURING LONG-TERM ORAL BISPHOSPHONATES TREATMENT: IMPLICATIONS FOR TREATMENT FAILURE AND "DRUG HOLIDAY" IN THE REAL WORLD.

PubMed

Liel, Yair; Plakht, Ygal; Tailakh, Muhammad Abu

2017-07-01

Little data exist to support concerns over bone turnover suppression during prolonged oral bisphosphonate treatment and on consequences of the recommended "drug holiday." This study was performed to assess bone resorption rates in postmenopausal osteoporotic women on prolonged oral bisphosphonate treatment and in response to switching to "drug holiday" intravenous bisphosphonate, or continuation of oral bisphosphonates. The frequency distribution of the bone resorption marker urinary deoxypyridinoline crosslinks (uDPD), was obtained retrospectively from 211 osteoporotic women attended at an academic hospital endocrine clinic, treated for >2 years with oral bisphosphonates. In some patients, uDPD was re-assessed following modification or continuation of treatment. The mean duration of oral bisphosphonates treatment was 7.2 ± 3.1 years. uDPD was within reference range for premenopausal women in 61.6% of the patients, below in 7.6% of the patients, and above upper limit in 30.8%. uDPD decreased significantly following intravenous zoledronic acid, increased significantly during "drug holiday," and slightly decreased in those continued on oral bisphosphonate treatment. In this real-world study, the majority of women on prolonged oral bisphosphonates maintained bone resorption rates within the normal reference range for premenopausal women. The likelihood for inadequate suppression was considerably greater than that of over-suppression. Implementing a "drug holiday" resulted in a marked increase in bone resorption rates. Additional studies should explore the potential role of bone turnover markers in the evaluation of patients on prolonged oral bisphosphonates and during "drug holiday" in different settings and using additional markers. BMD = bone mineral density; IQR = interquartile range; uDPD = urinary deoxypyridinoline crosslinks.

Breastfeeding and postmenopausal osteoporosis.

PubMed

Grimes, Julia P; Wimalawansa, Sunil J

2003-06-01

Bone loss associated with osteoporosis occurs with high frequency among the elderly and often results in debilitating fractures. A combination of lifestyle behaviors, genetic predisposition, and disease processes contributes to bone metabolism. Therefore, any discussion regarding bone health must address these factors. The impact of menopause on bone turnover has been generally well studied and characterized. Breastfeeding places significant stress on calcium metabolism and, as a consequence, directly influences bone metabolism. The most significant factors affecting bone mineral density (BMD) and bone metabolism are the duration and frequency of lactation, the return of menses, and pre-pregnancy weight. Although transient, lactation is associated with bone loss. As clinical guidelines and public health policies are being formulated, there is a compelling need for further investigation into the relationship of lactation, BMD, and subsequent risk of osteoporosis. Better understanding of this relationship will provide new opportunities for early intervention and ultimately help in the prevention of bone loss in postmenopausal women.

Test of a mediated performance-turnover relationship highlighting the moderating roles of visibility and reward contingency.

PubMed

Allen, D G; Griffeth, R W

2001-10-01

Despite the importance of understanding the conditions under which high performing employees are more likely or less likely to voluntarily leave an organization, the nature of the relationship between job performance and voluntary turnover has proven to be elusive. A model of the performance-turnover relationship that highlights important moderators and mediators is proposed and tested. Data consisted of organizational performance and turnover records and survey responses for 130 employees of a medical services organization. Results indicate that visibility and reward contingencies moderate performance relationships with alternatives and job satisfaction, respectively, and that performance may influence turnover through multiple mechanisms.

Effects of Aging and Cyclosporin A on Collagen Turnover in Human Gingiva

PubMed Central

Gagliano, N; Costa, F; Tartaglia, G.M; Pettinari, L; Grizzi, F; Sforza, C; Portinaro, N; Gioia, M; Annoni, G

2009-01-01

Background: We aimed at characterizing the aging gingiva analyzing: i) collagen content and turnover in human gingival tissues and fibroblasts obtained from healthy young and aging subjects. ii) the effect of cyclosporin A administration in human cultured gingival fibroblasts obtained from aging compared to young subjects. Methods: Morphological analysis was performed on haematoxylin-eosin and Sirius red stained paraffin-embedded gingival biopsies from young and aging healthy subjects. The expression of the main genes and proteins involved in collagen turnover were determined by real time PCR, dot blot and SDS-zymography on cultured young and aging gingival fibroblasts, and after cyclosporin A administration. Results: Our results suggest that in healthy aged people, gingival connective tissue is characterized by a similar collagen content and turnover. Collagen turnover pathways are similarly affected by cyclosporin A treatment in young and aging gingival fibroblasts. Conclusions: Cyclosporin A administration affects gingival collagen turnover pathways in young and aging fibroblasts at the same extent, suggesting that during aging cyclosporin A administration is not related to relevant collagen turnover modifications. PMID:20148173

Impact of work environment and work-related stress on turnover intention in physical therapists.

PubMed

Lee, Byoung-Kwon; Seo, Dong-Kwon; Lee, Jang-Tae; Lee, A-Ram; Jeon, Ha-Neul; Han, Dong-Uk

2016-08-01

[Purpose] This study was conducted to provide basic data for solutions to reduce the turnover rate of physical therapists. It should help create efficient personnel and organization management by exploring the impact of the work environment and work-related stress on turnover intention and analyzing the correlation between them. [Subjects and Methods] A survey was conducted with 236 physical therapists working at medical institutions in the Daejeon and Chungcheong areas. For the analysis on the collected data, correlational and linear regression analyses were conducted using the SPSS 18.0 program and Cronbach's alpha coefficient. [Results] The results showed a statistically significant positive correlation between turnover intention and work-related stress but a statistically significant negative correlation respectively between turnover intention and work environment. Work-related stress (β=0.415) had a significant positive impact on turnover intention and work environment (β=-0.387) had a significant negative impact on turnover intention. [Conclusion] To increase satisfaction level with the profession as well as the workplace for physical therapists, improvement of the work environment was the most necessary primary improvement.

Impact of work environment and work-related stress on turnover intention in physical therapists

PubMed Central

Lee, Byoung-kwon; Seo, Dong-kwon; Lee, Jang-Tae; Lee, A-Ram; Jeon, Ha-Neul; Han, Dong-Uk

2016-01-01

[Purpose] This study was conducted to provide basic data for solutions to reduce the turnover rate of physical therapists. It should help create efficient personnel and organization management by exploring the impact of the work environment and work-related stress on turnover intention and analyzing the correlation between them. [Subjects and Methods] A survey was conducted with 236 physical therapists working at medical institutions in the Daejeon and Chungcheong areas. For the analysis on the collected data, correlational and linear regression analyses were conducted using the SPSS 18.0 program and Cronbach’s alpha coefficient. [Results] The results showed a statistically significant positive correlation between turnover intention and work-related stress but a statistically significant negative correlation respectively between turnover intention and work environment. Work-related stress (β=0.415) had a significant positive impact on turnover intention and work environment (β=−0.387) had a significant negative impact on turnover intention. [Conclusion] To increase satisfaction level with the profession as well as the workplace for physical therapists, improvement of the work environment was the most necessary primary improvement. PMID:27630432

Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

PubMed Central

2009-01-01

Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp*1 and Hp *2 alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp*1 allele has two subtypes, Hp *1F and Hp *1S , that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp*1F allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp*1F/Hp*1S allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp*1F allele. However, despite the large variation in Hp*1F frequencies, results of F ST (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp*1F and Hp*1S frequencies among non-Amerindian Brazilians. PMID:21637505

Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities.

PubMed

Miranda-Vilela, Ana L; Akimoto, Arthur K; Alves, Penha C Z; Hiragi, Cássia O; Penalva, Guilherme C; Oliveira, Silviene F; Grisolia, Cesar K; Klautau-Guimarães, Maria N

2009-07-01

Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp(*1) and Hp (*2) alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp(*1) allele has two subtypes, Hp (*1F) and Hp (*1S) , that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp(*1F) allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp(*1F)/Hp(*1S) allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp(*1F) allele. However, despite the large variation in Hp(*1F) frequencies, results of F (ST) (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp(*1F) and Hp(*1S) frequencies among non-Amerindian Brazilians.

Work Context Interactions, Work Climate and Turnover.

DTIC Science & Technology

1983-10-01

AD-A133 893 WORK CONTEXT INTERACTIONS WORK CLIMATE AND TURNOVER(U) 1/f MICHIGAN STATE UNIV tAST LANSING B SCHNEIDER OCT 83 RR-83-2 NOSOTA-79-C-0781...CATALOG NUMBER -) L SIL ad utte. TYPE OF REPORT 6 PERIOD COVERED Work Context Interactions, Work Climate and FnlRpr Turnover: Final Report...reverse aide If necesaranmd Identify by block number) Work climate turnover organizational climate interactional psychology realistic job preview job

Interprofessional Simulations Promote Knowledge Retention and Enhance Perceptions of Teamwork Skills in a Surgical-Trauma-Burn Intensive Care Unit Setting.

PubMed

George, Katie L; Quatrara, Beth

The current state of health care encompasses highly acute, complex patients, managed with ever-changing technology. The ability to function proficiently in critical care relies on knowledge, technical skills, and interprofessional teamwork. Integration of these factors can improve patient outcomes. Simulation provides "hands-on" practice and allows for the integration of teamwork into knowledge/skill training. However, simulation can require a significant investment of time, effort, and financial resources. The Institute of Medicine recommendations from 2015 include "strengthening the evidence base for interprofessional education (IPE)" and "linking IPE with changes in collaborative behavior." In one surgical-trauma-burn intensive care unit (STBICU), no IPE existed. The highly acute and diverse nature of the patients served by the unit highlights the importance of appropriate training. This is heightened during critical event situations where patients deteriorate rapidly and the team intervenes swiftly. The aims of this study were to (1) evaluate knowledge retention and analyze changes in perceptions of teamwork among nurses and resident physicians in a STBICU setting after completion of an interprofessional critical event simulation and (2) provide insight for future interprofessional simulations (IPSs), including the ideal frequency of such training, associated cost, and potential effect on nursing turnover. A comparison-cohort pilot study was developed to evaluate knowledge retention and analyze changes in perceptions of teamwork. A 1-hour critical event IPS was held for nurses and resident physicians in a STBICU setting. A traumatic brain injury patient with elevated intracranial pressure, rapid deterioration, and cardiac arrest was utilized for the simulation scenario. The simulation required the team to use interventions to reduce elevated intracranial pressure and then perform cardiac resuscitation according to Advanced Cardiac Life Support guidelines. A semistructured debriefing guided by the TENTS tool highlighted important aspects of teamwork. Participants took knowledge and Teamwork Skills Scale (TSS) pretests, posttests, and 1-month posttests. Mean scores were calculated for each time point (pre, post, and 1-month post), and paired t tests were used to evaluate changes. Mean knowledge test and TSS scores both significantly increased after the simulation and remained significantly elevated at 1-month follow-up. Participants recommended retraining intervals of 3 to 6 months. Cost of each simulation was estimated to be $324.44. Analysis of nursing turnover rates did not demonstrate a statistically significant reduction in turnover; however, confounding factors were not controlled for. Significant improvements on both knowledge test and TSS scores demonstrate the effectiveness of the intervention, and retention of the information gained and teamwork skills learned. Participants valued the intervention and recommended to increase the frequency of training. Future studies should develop a framework for "best practice" IPS, analyze the relationship with nursing turnover, and ultimately seek correlations between IPS and improved patient outcomes.

The relationship between South Korean clinical nurses' attitudes toward organizations and voluntary turnover intention: A path analysis.

PubMed

Kim, Jong Kyung; Chang, Sun Ju

2015-08-01

The purpose of this study was to examine the relationship between attitudes toward their organizations and voluntary turnover intention among South Korean clinical nurses. Data from a total of 312 clinical nurses in six hospitals in South Korea were collected for the study. Both hierarchical multiple regression analysis and path analysis were used to analyse the data. The overall fit of the hypothetical model was good. Voluntary turnover intention was found to have significant direct pathways to job embeddedness and organizational commitment. Organizational commitment and satisfaction with organizational rewards had indirect pathways to voluntary turnover intention through job embeddedness. All variances explained 62.3% of the voluntary turnover intention scores. The findings suggest that greater job embeddedness, organizational commitment and satisfaction with organizational rewards lead to lower voluntary turnover intention among clinical nurses in South Korea. © 2014 Wiley Publishing Asia Pty Ltd.

Perceived Work Conditions and Turnover Intentions: The Mediating Role of Meaning of Work

PubMed Central

Arnoux-Nicolas, Caroline; Sovet, Laurent; Lhotellier, Lin; Di Fabio, Annamaria; Bernaud, Jean-Luc

2016-01-01

Perceived working conditions lead to various negative outcomes for employee behaviors, including turnover intentions. Although potential mediators for these relationships were previously identified, the importance of meaning of work has not yet been investigated. This study examines the role of this psychological resource as a mediator for the relationships between perceived working conditions and turnover intentions in a sample of 336 French workers from different job contexts. Results show that adverse working conditions were positively and significantly associated with turnover intentions. Meaning of work is negatively related to both perceived working conditions and turnover intentions. Mediation analyses for meaning of work demonstrated indirect effects of several adverse working conditions on turnover intentions. The role of meaning of work as a psychological resource for employees facing adverse working conditions is discussed, especially regarding its implications for research and practice within organizational contexts. PMID:27242616

Occupational stress and employee turnover.

PubMed

Bridger, Robert S; Day, Andrea J; Morton, Kate

2013-01-01

Questionnaire data captured in January-March 2007 were examined in relation to turnover in males and females during the next five years. In general, most of the workplace stressors (such as role conflict or peer support) were not antecedents of turnover in any group. Junior personnel with psychological strain in 2007 had an increased risk of turnover in the next five years. Low commitment to the service in 2007 increased the odds of turnover in male and female juniors and in female officers. Female juniors with less effective skills for coping with stress and who exercised less frequently on a weekly basis were more likely to leave. An incidental finding was that the odds of turnover were three times greater in female officers with children than in female officers with no children. Stress management interventions focusing on effective coping and sports and exercise participation which are targeted appropriately may improve retention.

Perceived Work Conditions and Turnover Intentions: The Mediating Role of Meaning of Work.

PubMed

Arnoux-Nicolas, Caroline; Sovet, Laurent; Lhotellier, Lin; Di Fabio, Annamaria; Bernaud, Jean-Luc

2016-01-01

Perceived working conditions lead to various negative outcomes for employee behaviors, including turnover intentions. Although potential mediators for these relationships were previously identified, the importance of meaning of work has not yet been investigated. This study examines the role of this psychological resource as a mediator for the relationships between perceived working conditions and turnover intentions in a sample of 336 French workers from different job contexts. Results show that adverse working conditions were positively and significantly associated with turnover intentions. Meaning of work is negatively related to both perceived working conditions and turnover intentions. Mediation analyses for meaning of work demonstrated indirect effects of several adverse working conditions on turnover intentions. The role of meaning of work as a psychological resource for employees facing adverse working conditions is discussed, especially regarding its implications for research and practice within organizational contexts.

One hundred years of employee turnover theory and research.

PubMed

Hom, Peter W; Lee, Thomas W; Shaw, Jason D; Hausknecht, John P

2017-03-01

We review seminal publications on employee turnover during the 100-year existence of the Journal of Applied Psychology . Along with classic articles from this journal, we expand our review to include other publications that yielded key theoretical and methodological contributions to the turnover literature. We first describe how the earliest papers examined practical methods for turnover reduction or control and then explain how theory development and testing began in the mid-20th century and dominated the academic literature until the turn of the century. We then track 21st century interest in the psychology of staying (rather than leaving) and attitudinal trajectories in predicting turnover. Finally, we discuss the rising scholarship on collective turnover given the centrality of human capital flight to practitioners and to the field of human resource management strategy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Staff nurse turnover costs: Part II, Measurements and results.

PubMed

Jones, C B

1990-05-01

This study demonstrated that the costs of nursing turnover can be high (over +10,000 per RN turnover), and that the potential for adverse impact on the nursing department, the hospital environment, and the healthcare environment exists. The results of this study are important, particularly in the midst of a national nursing shortage, for several reasons. CNEs are responsible for obtaining, allocating, and managing nursing department resources; knowledge of nursing turnover costs will allow them to make more informed decisions about how best to allocate scarce resources. The findings of this study are also important to hospital administrators because they demonstrate the financial impact of high rates of nursing turnover on healthcare delivery. Finally, these findings provide nurse researchers direction for future research into the costs and benefits of nursing turnover and retention activities, so that cost-effective methods of minimizing organizational costs can be determined.

Top Nurse-Management Staffing Collapse and Care Quality in Nursing Homes

PubMed Central

Hunt, Selina R.; Corazzini, Kirsten; Anderson, Ruth A.

2014-01-01

Director of nursing turnover is linked to staff turnover and poor quality of care in nursing homes; however the mechanisms of these relationships are unknown. Using a complexity science framework, we examined how nurse management turnover impacts system capacity to produce high quality care. This study is a longitudinal case analysis of a nursing home (n = 97 staff) with 400% director of nursing turnover during the study time period. Data included 100 interviews, observations and documents collected over 9 months and were analyzed using immersion and content analysis. Turnover events at all staff levels were nonlinear, socially mediated and contributed to dramatic care deficits. Federal mandated, quality assurance mechanisms failed to ensure resident safety. High multilevel turnover should be elevated to a sentinel event for regulators. Suggestions to magnify positive emergence in extreme conditions and to improve quality are provided. PMID:24652943

Electrochemical Reduction of CO 2 Catalyzed by Re(pyridine-oxazoline)(CO) 3 Cl Complexes

DOE PAGES

Nganga, John K.; Samanamu, Christian R.; Tanski, Joseph M.; ...

2017-03-09

In a series of rhenium tricarbonyl complexes coordinated by asymmetric diimine ligands containing a pyridine moiety bound to an oxazoline ring were synthesized, structurally and electrochemically characterized, and screened for CO 2 reduction ability. We reported complexes are of the type Re(N-N)(CO) 3Cl, with N-N = 2-(pyridin-2-yl)-4,5-dihydrooxazole (1), 5-methyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (2), and 5-phenyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (3). The electrocatalytic reduction of CO 2 by these complexes was observed in a variety of solvents and proceeds more quickly in acetonitrile than in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The analysis of the catalytic cycle for electrochemical CO 2 reduction by 1 in acetonitrile using densitymore » functional theory (DFT) supports the C–O bond cleavage step being the rate-determining step (RDS) (ΔG ‡ = 27.2 kcal mol –1). Furthermore, the dependency of the turnover frequencies (TOFs) on the donor number (DN) of the solvent also supports that C–O bond cleavage is the rate-determining step. Moreover, the calculations using explicit solvent molecules indicate that the solvent dependence likely arises from a protonation-first mechanism. Unlike other complexes derived from fac-Re(bpy)(CO) 3Cl (I; bpy = 2,2'-bipyridine), in which one of the pyridyl moieties in the bpy ligand is replaced by another imine, no catalytic enhancement occurs during the first reduction potential. Remarkably, catalysts 1 and 2 display relative turnover frequencies, (i cat/i p) 2, up to 7 times larger than that of I.« less

National Bone Health Alliance Bone Turnover Marker Project: current practices and the need for US harmonization, standardization, and common reference ranges.

PubMed

Bauer, D; Krege, J; Lane, N; Leary, E; Libanati, C; Miller, P; Myers, G; Silverman, S; Vesper, H W; Lee, D; Payette, M; Randall, S

2012-10-01

This position paper reviews how the National Bone Health Alliance (NBHA) will execute a project to help assure health professionals of the clinical utility of bone turnover markers; the current clinical approaches concerning osteoporosis and the status and use of bone turnover markers in the USA; the rationale for focusing this effort around two specific bone turnover markers; the need to standardize bone marker sample collection procedures, reference ranges, and bone turnover marker assays in clinical laboratories; and the importance of harmonization for future research of bone turnover markers. Osteoporosis is a major global health problem, with the prevalence and incidence of osteoporosis for at-risk populations estimated to be 44 million Americans. The potential of bone markers as an additional tool for health care professionals to improve patient outcomes and impact morbidity and mortality is crucial in providing better health care and addressing rising health care costs. This need to advance the field of bone turnover markers has been recognized by a number of organizations, including the International Osteoporosis Foundation (IOF), National Osteoporosis Foundation, International Federation of Clinical Chemistry, and Laboratory Medicine (IFCC), and the NBHA. This position paper elucidates how this project will standardize bone turnover marker sample collection procedures in the USA, establish a USA reference range for one bone formation (serum procollagen type I N propeptide, s-PINP) and one bone resorption (serum C-terminal telopeptide of type I collagen, s-CTX) marker, and standardize bone turnover marker assays used in clinical laboratories. This effort will allow clinicians from the USA to have confidence in their use of bone turnover markers to help monitor osteoporosis treatment and assess future fracture risk. This project builds on the recommendations of the IOF/IFCC Bone Marker Standards Working Group by developing USA reference standards for s-PINP and s-CTX, the markers identified as most promising for use as reference markers. The goals of this project will be realized through the NBHA and will include its governmental, academic, for-profit, and non-profit sector stakeholders as well as major academic and commercial laboratories. Upon completion, a parallel effort will be pursued to make bone turnover marker measurements reliable and accepted by all health care professionals for facilitating treatment decisions and ultimately be reimbursed by all health insurance payers. Successful completion of this project will help assure health professionals from the USA of the clinical utility of bone turnover markers and ties in with the parallel effort of the IOF/IFCC to develop worldwide bone turnover reference ranges.

The relationship between quality of work life and turnover intention of primary health care nurses in Saudi Arabia.

PubMed

Almalki, Mohammed J; FitzGerald, Gerry; Clark, Michele

2012-09-12

Quality of work life (QWL) has been found to influence the commitment of health professionals, including nurses. However, reliable information on QWL and turnover intention of primary health care (PHC) nurses is limited. The aim of this study was to examine the relationship between QWL and turnover intention of PHC nurses in Saudi Arabia. A cross-sectional survey was used in this study. Data were collected using Brooks' survey of Quality of Nursing Work Life, the Anticipated Turnover Scale and demographic data questions. A total of 508 PHC nurses in the Jazan Region, Saudi Arabia, completed the questionnaire (RR = 87%). Descriptive statistics, t-test, ANOVA, General Linear Model (GLM) univariate analysis, standard multiple regression, and hierarchical multiple regression were applied for analysis using SPSS v17 for Windows. Findings suggested that the respondents were dissatisfied with their work life, with almost 40% indicating a turnover intention from their current PHC centres. Turnover intention was significantly related to QWL. Using standard multiple regression, 26% of the variance in turnover intention was explained by QWL, p < 0.001, with R2 = .263. Further analysis using hierarchical multiple regression found that the total variance explained by the model as a whole (demographics and QWL) was 32.1%, p < 0.001. QWL explained an additional 19% of the variance in turnover intention, after controlling for demographic variables. Creating and maintaining a healthy work life for PHC nurses is very important to improve their work satisfaction, reduce turnover, enhance productivity and improve nursing care outcomes.

Are workers who leave a job exposed to similar physical demands as workers who develop clinically meaningful declines in low-back function?

PubMed

Ferguson, Sue A; Marras, William S; Lavender, Steven A; Splittstoesser, Riley E; Yang, Gang

2014-02-01

The objective is to quantify differences in physical exposures for those who stayed on a job (survivor) versus those who left the job (turnover). It has been suggested that high physical job demands lead to greater turnover and that turnover rates may supplement low-back disorder incidence rates in passive surveillance systems. A prospective study with 811 participants was conducted. The physical exposure of distribution center work was quantified using a moment monitor. A total of 68 quantitative physical exposure measures in three categories (load, position, and timing) were examined. Low-back health function was quantified using the lumbar motion monitor at baseline and 6-month follow-up. There were 365 turnover employees within the 6-month follow-up period and 446 "survivors" who remained on the same job, of which 126 survivors had a clinically meaningful decline in low-back functional performance (cases) and 320 survivors did not have a meaningful decline in low-back functional performance (noncases). Of the job exposure measures, 6% were significantly different between turnover and cases compared to 69% between turnover and noncases. Turnover employees had significantly greater exposure compared to noncases. Turnover employees had similar physical job exposures to workers who remained on the job and had a clinically meaningful decline in low-back functional performance. Thus, ergonomists and HR should be aware that high turnover jobs appear to have similar physical exposure as those jobs that put workers at risk for a decline in low-back functional performance.

Organizational commitment as a predictor variable in nursing turnover research: literature review.

PubMed

Wagner, Cheryl M

2007-11-01

This paper is a report of a literature review to (1) demonstrate the predictability of organizational commitment as a variable, (2) compare organizational commitment and job satisfaction as predictor variables and (3) determine the usefulness of organizational commitment in nursing turnover research. Organizational commitment is not routinely selected as a predictor variable in nursing studies, although the evidence suggests that it is a reliable predictor. Findings from turnover studies can help determine the previous performance of organizational commitment, and be compared to those of studies using the more conventional variable of job satisfaction. Published research studies in English were accessed for the period 1960-2006 using the CINAHL, EBSCOHealthsource Nursing, ERIC, PROQUEST, Journals@OVID, PubMed, PsychINFO, Health and Psychosocial Instruments (HAPI) and COCHRANE library databases and Business Source Premier. The search terms included nursing turnover, organizational commitment or job satisfaction. Only studies reporting mean comparisons, R(2) or beta values related to organizational commitment and turnover or turnover antecedents were included in the review. There were 25 studies in the final data set, with a subset of 23 studies generated to compare the variables of organizational commitment and job satisfaction. Results indicated robust indirect predictability of organizational commitment overall, with greater predictability by organizational commitment vs job satisfaction. Organizational commitment is a useful predictor of turnover in nursing research, and effective as a variable with the most direct impact on antecedents of turnover such as intent to stay. The organizational commitment variable should be routinely employed in nursing turnover research studies.

Investigating the adequacy of the Competence-Turnover Intention Model: how does nursing competence affect nurses' turnover intention?

PubMed

Takase, Miyuki; Teraoka, Sachiko; Kousuke, Yabase

2015-03-01

The aim of this study was to test the adequacy of the Competence-Turnover Intention Model, which was developed to identify how nursing competence could affect nurses' turnover intention (nurses' intention to voluntarily leave an organisation). Recent studies have suggested that the level of nursing competence is negatively related to nurses' intention to leave their jobs, suggesting that a lack of competence threatens both the quality and quantity of the nursing workforce. However, the mechanism of how nursing competence affects nurses' turnover intention has not been explored previously. A cross-sectional survey design was used. Surveys were distributed to 1337 Japanese registered nurses/midwives in October, 2013. The adequacy of the model was analysed using structural equation modelling. In total, 766 questionnaires were returned, with a return rate of 57%. The model fitted well with the data. The results showed that the level of nursing competence was related positively to the quantity of organisational rewards they felt they had received, and negatively related to the level of exhaustion they experienced. Moreover, the perceived organisational rewards and exhaustion were correlated with nurses' turnover intention through affective commitment. The Competence-Turnover Intention Model is useful for explaining how nursing competence impacts on their turnover intention. Clinical implications derived from the findings are that: promoting nursing competence is key to improving not only the quality of care provided by nurses, but also to retaining the nursing workforce, and the model can be used to develop strategies that would mitigate their turnover intention. © 2014 John Wiley & Sons Ltd.

Comparison of Unit-Level Patient Turnover Measures in Acute Care Hospital Settings.

PubMed

Park, Shin Hye; Dunton, Nancy; Blegen, Mary A

2016-06-01

High patient turnover is a critical factor increasing nursing workload. Despite the growing number of studies on patient turnover, no consensus about how to measure turnover has been achieved. This study was designed to assess the correlation among patient turnover measures commonly used in recent studies and to examine the degree of agreement among the measures for classifying units with different levels of patient turnover. Using unit-level data collected for this study from 292 units in 88 hospitals participating in the National Database of Nursing Quality Indicators®, we compared four patient turnover measures: the inverse of length of stay (1/LOS), admissions, discharges, and transfers per daily census (ADTC), ADTC with short-stay adjustment, and the number of ADTs and short-stay patients divided by the total number of treated patients, or Unit Activity Index (UAI). We assessed the measures' agreement on turnover quartile classifications, using percent agreement and Cohen's kappa statistic (weighted and unweighted). Pearson correlation coefficients also were calculated. ADTC with or without adjustment for short-stay patients had high correlations and substantial agreement with the measure of 1/LOS (κ = .62 to .91; r = .90 to .95). The UAI measure required data less commonly collected by participating hospital units and showed only moderate correlations and fair agreement with the other measures (κ = .23 to .39; r = .41 to .45). The UAI may not be comparable and interchangeable with other patient turnover measures when data are obtained from multiple units and hospitals. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Physician and staff turnover in community primary care practice.

PubMed

Ruhe, Mary; Gotler, Robin S; Goodwin, Meredith A; Stange, Kurt C

2004-01-01

The effect of a rapidly changing healthcare system on personnel turnover in community family practices has not been analyzed. We describe physician and staff turnover and examine its association with practice characteristics and patient outcomes. A cross-sectional evaluation of length of employment of 150 physicians and 762 staff in 77 community family practices in northeast Ohio was conducted. Research nurses collected data using practice genograms, key informant interviews, staff lists, practice environment checklists, medical record reviews, and patient questionnaires. The association of physician and staff turnover with practice characteristics, patient satisfaction, and preventive service data was tested. During a 2-year period, practices averaged a 53% turnover rate of staff. The mean length of duration of work at the current practice location was 9.1 years for physicians and 4.1 years for staff. Longevity varied by position, with a mean of 3.4 years for business employees, 4.0 years for clinical employees, and 7.8 years for office managers. Network-affiliated practices experienced higher turnover than did independent practices. Physician longevity was associated with a practice focus on managing chronic illness, keeping on schedule, and responding to insurers' requests. No association was found between turnover and patient satisfaction or preventive service delivery rates. Personnel turnover is pervasive in community primary care practices and is associated with employee role, practice network affiliation, and practice focus. The potentially disruptive effect of personnel turnover on practice functioning, finances, and longitudinal relationships with patients deserves further study despite the reassuring lack of association with patient satisfaction and preventive service delivery rates.

The relationship between quality of work life and turnover intention of primary health care nurses in Saudi Arabia

PubMed Central

2012-01-01

Background Quality of work life (QWL) has been found to influence the commitment of health professionals, including nurses. However, reliable information on QWL and turnover intention of primary health care (PHC) nurses is limited. The aim of this study was to examine the relationship between QWL and turnover intention of PHC nurses in Saudi Arabia. Methods A cross-sectional survey was used in this study. Data were collected using Brooks’ survey of Quality of Nursing Work Life, the Anticipated Turnover Scale and demographic data questions. A total of 508 PHC nurses in the Jazan Region, Saudi Arabia, completed the questionnaire (RR = 87%). Descriptive statistics, t-test, ANOVA, General Linear Model (GLM) univariate analysis, standard multiple regression, and hierarchical multiple regression were applied for analysis using SPSS v17 for Windows. Results Findings suggested that the respondents were dissatisfied with their work life, with almost 40% indicating a turnover intention from their current PHC centres. Turnover intention was significantly related to QWL. Using standard multiple regression, 26% of the variance in turnover intention was explained by QWL, p < 0.001, with R2 = .263. Further analysis using hierarchical multiple regression found that the total variance explained by the model as a whole (demographics and QWL) was 32.1%, p < 0.001. QWL explained an additional 19% of the variance in turnover intention, after controlling for demographic variables. Conclusions Creating and maintaining a healthy work life for PHC nurses is very important to improve their work satisfaction, reduce turnover, enhance productivity and improve nursing care outcomes. PMID:22970764

Oxygen evolution from single- and multiple-turnover light pulses: temporal kinetics of electron transport through PSII in sunflower leaves.

PubMed

Oja, Vello; Eichelmann, Hillar; Laisk, Agu

2011-12-01

Oxygen evolution per single-turnover flash (STF) or multiple-turnover pulse (MTP) was measured with a zirconium O(2) analyzer from sunflower leaves at 22 °C. STF were generated by Xe arc lamp, MTP by red LED light of up to 18000 μmol quanta m(-2) s(-1). Ambient O(2) concentration was 10-30 ppm, STF and MTP were superimposed on far-red background light in order to oxidize plastoquinone (PQ) and randomize S-states. Electron (e(-)) flow was calculated as 4 times O(2) evolution. Q (A) → Q (B) electron transport was investigated firing double STF with a delay of 0 to 2 ms between the two. Total O(2) evolution per two flashes equaled to that from a single flash when the delay was zero and doubled when the delay exceeded 2 ms. This trend was fitted with two exponentials with time constants of 0.25 and 0.95 ms, equal amplitudes. Illumination with MTP of increasing length resulted in increasing O(2) evolution per pulse, which was differentiated with an aim to find the time course of O(2) evolution with sub-millisecond resolution. At the highest pulse intensity of 2.9 photons ms(-1) per PSII, 3 e(-) initially accumulated inside PSII and the catalytic rate of PQ reduction was determined from the throughput rate of the fourth and fifth e(-). A light response curve for the reduction of completely oxidized PQ was a rectangular hyperbola with the initial slope of 1.2 PSII quanta per e(-) and V (m) of 0.6 e(-) ms(-1) per PSII. When PQ was gradually reduced during longer MTP, V (m) decreased proportionally with the fraction of oxidized PQ. It is suggested that the linear kinetics with respect to PQ are apparent, caused by strong product inhibition due to about equal binding constants of PQ and PQH(2) to the Q (B) site. The strong product inhibition is an appropriate mechanism for down-regulation of PSII electron transport in accordance with rate of PQH(2) oxidation by cytochrome b(6)f. © Springer Science+Business Media B.V. 2011

Depth dependent microbial carbon use efficiency in the capillary fringe as affected by water table fluctuations in a column incubation experiment

NASA Astrophysics Data System (ADS)

Pronk, G. J.; Mellage, A.; Milojevic, T.; Smeaton, C. M.; Rezanezhad, F.; Van Cappellen, P.

2017-12-01

Microbial growth and turnover of soil organic carbon (SOC) depend on the availability of electron donors and acceptors. The steep geochemical gradients in the capillary fringe between the saturated and unsaturated zones provide hotspots of soil microbial activity. Water table fluctuations and the associated drying and wetting cycles within these zones have been observed to lead to enhanced turnover of SOC and adaptation of the local microbial communities. To improve our understanding of SOC degradation under changing moisture conditions, we carried out an automated soil column experiment with integrated of hydro-bio-geophysical monitoring under both constant and oscillating water table conditions. An artificial soil mixture composed of quartz sand, montmorillonite, goethite and humus was used to provide a well-defined system. This material was inoculated with a microbial community extracted from a forested riparian zone. The soils were packed into 6 columns (60 cm length and 7.5 cm inner diameter) to a height of 45 cm; and three replicate columns were incubated under constant water table while another three were saturated and drained monthly. The initial soil development, carbon cycling and microbial community development were then characterized during 10 months of incubation. This system provides an ideal artificial gradient from the saturated to the unsaturated zone to study soil development from initially homogeneous materials and the same microbial community composition under controlled conditions. Depth profiles of SOC and microbial biomass after 329 days of incubation showed a depletion of carbon in the transition drying and wetting zone that was not associated with higher accumulation of microbial biomass, indicating a lower carbon use efficiency of the microbial community established within the water table fluctuation zone. This was supported by a higher ATP to microbial biomass carbon ratio within the same zone. The findings from this study highlight the importance of considering the effects of transient soil moisture and oxygen availability on microbial mediated SOC transformations. The effects of these changes in carbon use efficiency need to be included in soil models in order to accurately predict SOC turnover.

The Effect of Parasite Infection on Stable Isotope Turnover Rates of δ15N, δ13C and δ34S in Multiple Tissues of Eurasian Perch Perca fluviatilis.

PubMed

Yohannes, Elizabeth; Grimm, Claudia; Rothhaupt, Karl-Otto; Behrmann-Godel, Jasminca

2017-01-01

Stable isotope analysis of commercially and ecologically important fish can improve understanding of life-history and trophic ecology. However, accurate interpretation of stable isotope values requires knowledge of tissue-specific isotopic turnover that will help to describe differences in the isotopic composition of tissues and diet. We performed a diet-switch experiment using captive-reared parasite-free Eurasian perch (Perca fluviatilis) and wild caught specimens of the same species, infected with the pike tapeworm Triaenophorus nodulosus living in host liver tissue. We hypothesize that metabolic processes related to infection status play a major role in isotopic turnover and examined the influence of parasite infection on isotopic turn-over rate of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in liver, blood and muscle. The δ15N and δ13C turnovers were fastest in liver tissues, followed by blood and muscle. In infected fish, liver and blood δ15N and δ13C turnover rates were similar. However, in infected fish, liver and blood δ13C turnover was faster than that of δ15N. Moreover, in infected subjects, liver δ15N and δ13C turnover rates were three to five times faster than in livers of uninfected subjects (isotopic half-life of ca.3-4 days compared to 16 and 10 days, respectively). Blood δ34S turnover rate were about twice faster in non-infected individuals implying that parasite infection could retard the turnover rate of δ34S and sulphur containing amino acids. Slower turnover rate of essential amino acid could probably decrease individual immune function. These indicate potential hidden costs of chronic and persistent infections that may have accumulated adverse effects and might eventually impair life-history fitness. For the first time, we were able to shift the isotope values of parasites encapsulated in the liver by changing the dietary source of the host. We also report variability in isotopic turnover rates between tissues, elements and between infected and parasite-free individuals. These results contribute to our understanding of data obtained from field and commercial hatcheries; and strongly improve the applicability of the stable isotope method in understanding life-history and trophic ecology of fish populations.

The Effect of Parasite Infection on Stable Isotope Turnover Rates of δ15N, δ13C and δ34S in Multiple Tissues of Eurasian Perch Perca fluviatilis

PubMed Central

Yohannes, Elizabeth; Grimm, Claudia; Rothhaupt, Karl-Otto; Behrmann-Godel, Jasminca

2017-01-01

Stable isotope analysis of commercially and ecologically important fish can improve understanding of life-history and trophic ecology. However, accurate interpretation of stable isotope values requires knowledge of tissue-specific isotopic turnover that will help to describe differences in the isotopic composition of tissues and diet. We performed a diet-switch experiment using captive-reared parasite-free Eurasian perch (Perca fluviatilis) and wild caught specimens of the same species, infected with the pike tapeworm Triaenophorus nodulosus living in host liver tissue. We hypothesize that metabolic processes related to infection status play a major role in isotopic turnover and examined the influence of parasite infection on isotopic turn-over rate of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in liver, blood and muscle. The δ15N and δ13C turnovers were fastest in liver tissues, followed by blood and muscle. In infected fish, liver and blood δ15N and δ13C turnover rates were similar. However, in infected fish, liver and blood δ13C turnover was faster than that of δ15N. Moreover, in infected subjects, liver δ15N and δ13C turnover rates were three to five times faster than in livers of uninfected subjects (isotopic half-life of ca.3-4 days compared to 16 and 10 days, respectively). Blood δ34S turnover rate were about twice faster in non-infected individuals implying that parasite infection could retard the turnover rate of δ34S and sulphur containing amino acids. Slower turnover rate of essential amino acid could probably decrease individual immune function. These indicate potential hidden costs of chronic and persistent infections that may have accumulated adverse effects and might eventually impair life-history fitness. For the first time, we were able to shift the isotope values of parasites encapsulated in the liver by changing the dietary source of the host. We also report variability in isotopic turnover rates between tissues, elements and between infected and parasite-free individuals. These results contribute to our understanding of data obtained from field and commercial hatcheries; and strongly improve the applicability of the stable isotope method in understanding life-history and trophic ecology of fish populations. PMID:28046021

The radio spectral energy distribution of infrared-faint radio sources

NASA Astrophysics Data System (ADS)

Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

2016-10-01

Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of their optical and infrared faintness, it is very challenging to study IFRS at these wavelengths. However, IFRS are relatively bright in the radio regime with 1.4 GHz flux densities of a few to a few tens of mJy. Therefore, the radio regime is the most promising wavelength regime in which to constrain their nature. We aim to test the hypothesis that IFRS are young AGN, particularly GHz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources that have a low frequency turnover. Methods: We use the rich radio data set available for the Australia Telescope Large Area Survey fields, covering the frequency range between 150 MHz and 34 GHz with up to 19 wavebands from different telescopes, and build radio spectral energy distributions (SEDs) for 34 IFRS. We then study the radio properties of this class of object with respect to turnover, spectral index, and behaviour towards higher frequencies. We also present the highest-frequency radio observations of an IFRS, observed with the Plateau de Bure Interferometer at 105 GHz, and model the multi-wavelength and radio-far-infrared SED of this source. Results: We find IFRS usually follow single power laws down to observed frequencies of around 150 MHz. Mostly, the radio SEDs are steep (α < -0.8; %), but we also find ultra-steep SEDs (α < -1.3; %). In particular, IFRS show statistically significantly steeper radio SEDs than the broader RL AGN population. Our analysis reveals that the fractions of GPS and CSS sources in the population of IFRS are consistent with the fractions in the broader RL AGN population. We find that at least % of IFRS contain young AGN, although the fraction might be significantly higher as suggested by the steep SEDs and the compact morphology of IFRS. The detailed multi-wavelength SED modelling of one IFRS shows that it is different from ordinary AGN, although it is consistent with a composite starburst-AGN model with a star formation rate of 170 M⊙ yr-1. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

Denosumab is effective in the treatment of bone marrow oedema syndrome.

PubMed

Rolvien, Tim; Schmidt, Tobias; Butscheidt, Sebastian; Amling, Michael; Barvencik, Florian

2017-04-01

Bone marrow oedema (BMO) syndrome describes a painful condition with increase of interstitial fluid within bone and is often lately diagnosed due to unspecific symptoms. The underlying causes are diverse while it is widely assumed that in cases of BMO local bone resorption is increased. Denosumab, a human monoclonal antibody that binds to the receptor activator of nuclear factor kappa-B ligand (RANKL) inhibits osteoclastic bone resorption and is commonly administered in the treatment of osteoporosis. Besides one previous case report, its clinical effectiveness in the treatment of bone marrow oedema has not been elucidated. We treated 14 patients with primary (idiopathic) bone marrow oedema of the lower extremity with single dose denosumab application. Mean time between onset of pain and therapy was 155days. MRI scans were performed for initial diagnosis, and 6-12 weeks after denosumab injection. Vitamin D and calcium homeostasis were strived to be balanced before initiation of therapy. Furthermore bone status was analysed using Dual-energy X-ray absorptiometry (DXA) and extended bone turnover serum markers. After 6-12 weeks, BMO dissolved partly or completely in 93%, while a complete recovery was observed in 50% of the individuals. Visual analogue scale (VAS) evaluation revealed a significant decrease in pain level. Furthermore, bone turnover decreased significantly after treatment. No adverse reactions were reported. In conclusion, our retrospective analysis shows that denosumab is highly effective in the treatment of bone marrow oedema and therefore represents an alternative treatment option. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinase programs spatiotemporally regulate gap junction assembly and disassembly: effects on wound repair

PubMed Central

Solan, Joell L.; Lampe, Paul D.

2016-01-01

Gap junctions are highly ordered plasma membrane domains that are constantly assembled, remodeled and turned over due to the short half-life of connexins, the integral membrane proteins that form gap junctions. Connexin 43 (Cx43), by far the most widely expressed connexin, is phosphorylated at multiple serine residues in the cytoplasmic, C-terminal region allowing for exquisite cellular control over gap junctional communication. This is evident during epidermal wounding where spatiotemporal changes in connexin expression occur as cells are instructed whether to die, proliferate or migrate to promote repair. Early gap junctional communication is required for initiation of keratinocyte migration, but accelerated Cx43 turnover is also critical for proper wound healing at later stages. These events are controlled via a "kinase program" where sequential phosphorylation of Cx43 leads to reductions in Cx43’s half-life and significant depletion of gap junctions from the plasma membrane within several hours. The complex regulation of gap junction assembly and turnover affords several steps where intervention might speed wound healing. PMID:26706150

Kinase programs spatiotemporally regulate gap junction assembly and disassembly: Effects on wound repair.

PubMed

Solan, Joell L; Lampe, Paul D

2016-02-01

Gap junctions are highly ordered plasma membrane domains that are constantly assembled, remodeled and turned over due to the short half-life of connexins, the integral membrane proteins that form gap junctions. Connexin 43 (Cx43), by far the most widely expressed connexin, is phosphorylated at multiple serine residues in the cytoplasmic, C-terminal region allowing for exquisite cellular control over gap junctional communication. This is evident during epidermal wounding where spatiotemporal changes in connexin expression occur as cells are instructed whether to die, proliferate or migrate to promote repair. Early gap junctional communication is required for initiation of keratinocyte migration, but accelerated Cx43 turnover is also critical for proper wound healing at later stages. These events are controlled via a "kinase program" where sequential phosphorylation of Cx43 leads to reductions in Cx43's half-life and significant depletion of gap junctions from the plasma membrane within several hours. The complex regulation of gap junction assembly and turnover affords several steps where intervention might speed wound healing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the impact of scaffold architecture and mechanical loading on collagen turnover in engineered cardiovascular tissues.

PubMed

Argento, G; de Jonge, N; Söntjens, S H M; Oomens, C W J; Bouten, C V C; Baaijens, F P T

2015-06-01

The anisotropic collagen architecture of an engineered cardiovascular tissue has a major impact on its in vivo mechanical performance. This evolving collagen architecture is determined by initial scaffold microstructure and mechanical loading. Here, we developed and validated a theoretical and computational microscale model to quantitatively understand the interplay between scaffold architecture and mechanical loading on collagen synthesis and degradation. Using input from experimental studies, we hypothesize that both the microstructure of the scaffold and the loading conditions influence collagen turnover. The evaluation of the mechanical and topological properties of in vitro engineered constructs reveals that the formation of extracellular matrix layers on top of the scaffold surface influences the mechanical anisotropy on the construct. Results show that the microscale model can successfully capture the collagen arrangement between the fibers of an electrospun scaffold under static and cyclic loading conditions. Contact guidance by the scaffold, and not applied load, dominates the collagen architecture. Therefore, when the collagen grows inside the pores of the scaffold, pronounced scaffold anisotropy guarantees the development of a construct that mimics the mechanical anisotropy of the native cardiovascular tissue.