scholarly journals Do early trends in oak barrens fire treatment predict later outcomes? Insights from three decades of vegetation monitoring

Fire Ecology ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
John B. Taft

Abstract Background Vegetation structure, species diversity, and composition have been monitored at a fire-treatment and a fire-free control unit of a dry oak barrens and woodland complex in southern Illinois, USA, over a 29-year period and five burns. The restoration hypothesis is that fire management would result in different trends for vegetation parameters of conservation interest between fire treatment and control units, that before–after differences would be greater with fire management, and that early trends provide a reliable predictor for later outcomes. This study examines effectiveness of management in achieving restoration goals and uses response to the first two burns and monitoring results over the first seven years as an estimation period to test whether early trends with fire treatment are a reliable predictor for outcomes following three additional burns over the following 22 years. Results Trends differed between fire-treatment and control units for all parameters measured, and before–after differences were greater at the fire treatment unit. However, trends at the fire-treatment unit during the estimation period were a poor predictor of later outcomes. Tree density and basal area declined more than expected while ground-layer species density, richness, diversity, and percent cover did not keep pace with expectations of increase. Trends at the control unit were more predictable; however, tree basal area declined more than expected, possibly due to an outbreak of rapid white oak mortality disease, and decline of ground-layer species density was less than predicted from the early estimation period. Conclusions Results suggested that fire alone can be effective at restoring woodland and barrens natural areas and that a fire return interval of about every four years would be optimal for maintaining composition and diversity in this specific oak barrens habitat. However, burns followed immediately by severe drought possibly can have negative interactions, resulting in declines of ground-layer species diversity.

1998 ◽  
Vol 10 (4) ◽  
pp. 379-395 ◽  
Author(s):  
M. Powell Lawton ◽  
Kimberly Van Haitsma ◽  
Jennifer Klapper ◽  
Morton H. Kleban ◽  
Ira R. Katz ◽  
...  

Two equivalent special care nursing home units for elders with dementing illness were randomly designated as experimental and control units for an intervention called the “stimulation-retreat” model. This model introduced a set of staffing and program changes whose purpose was to diagnose, prescribe, and apply a package of care according to individual needs for additional stimulation or relief from stimulation (“retreat”). A total of 49 experimental and 48 control unit residents completed 12 months of care and were evaluated at baseline, 6 months, and 12 months. It was hypothesized that the intervention would not affect the basic disability (cognitive and activities of daily living functions), would improve negative behaviors and observed affects, and would have maximum impact in increasing positive behaviors and affects. Over time, most functions worsened, including negative attributes and affects. Lesser decline in positive affect and increases in external engagement, however, led to the conclusion that the intervention showed a marginally significant and selective effect on positive behaviors and affect.


2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Solomon Tibebu ◽  
Abebe Worku ◽  
Kenatu Angassa

This study aimed to evaluate the treatment potential of gradual hydroponics planted with Duranta erecta in the removal of pathogens from domestic wastewater. Two experimental and control units were configured in series. Each unit contains three bioreactors and was arranged in a cascaded configuration. The two experimental units used both plant and media, but the two control units used only media to treat the wastewater. Gravel and polyester sponge were used as media. Experimental unit 1 and control unit 1 used gravel as media; however, experimental unit 2 and control unit 2 used polyester sponges as media. The experiment was operated at hydraulic retention times of 1, 3, 5, and 7 days in a continuous mode. The performance of the hydroponic system was evaluated by characterizing the influent and effluent quality using standard methods. At optimum hydraulic retention time (7 days), the average removal of experimental units 1 and 2 was 98.7% and 89.8% for heterotrophic bacteria, 96.2% and 86.8% for total coliform, and 92.9% and 84.0% for fecal coliform, respectively. Analysis of variance showed that there was a significant difference P < 0.05 between the two experimental and control units in removing pathogens, but no significant difference P > 0.05 was observed between the two experimental units and between the two control units. Heterotrophic bacteria and coliforms were satisfactorily removed from domestic wastewater via a gradual hydroponic system. Hence, the hydroponic treatment system planted with Duranta erecta has a promising potential in the removal of pathogens from domestic wastewater in developing countries including Ethiopia.


2013 ◽  
Vol 431 ◽  
pp. 226-230
Author(s):  
Dong Hyun Seo ◽  
Wae Gyeong Shin ◽  
Jong Sang No

Algorithms for motor control unit in electric vehicles are being actively developed with consideration given to safety and reliability these days. Faults during driving are a critical problem that is directly linked to the safety of drivers, and studies on fault detection of control units in various situations are needed. This study investigated the faults of control units in a signal level interface with a dynamic model of drive motor and the real-time interconnection of motor control unit and HILS (hardware-in-the-loop simulation). It was found through real-time simulation that simulating the fault conditions with the sensors of motor control unit could reveal different characteristics of motor control unit. Furthermore, vehicle driving simulations with electric motor control were performed. The results of this study are expected to help the development of electric motor simulations and the evaluation of MCU and control algorithms.


2020 ◽  
pp. 107699862094627
Author(s):  
Nicole E. Pashley ◽  
Luke W. Miratrix

Evaluating blocked randomized experiments from a potential outcomes perspective has two primary branches of work. The first focuses on larger blocks, with multiple treatment and control units in each block. The second focuses on matched pairs, with a single treatment and control unit in each block. These literatures not only provide different estimators for the standard errors of the estimated average impact, but they are also built on different sets of assumptions. Neither literature handles cases with blocks of varying size that contain singleton treatment or control units, a case which can occur in a variety of contexts, such as with different forms of matching or poststratification. In this article, we reconcile the literatures by carefully examining the performance of variance estimators under several different frameworks. We then use these insights to derive novel variance estimators for experiments containing blocks of different sizes.


2008 ◽  
Vol 29 (8) ◽  
pp. 730-735 ◽  
Author(s):  
Alexandre R. Marra ◽  
Cláudia D'Arco ◽  
Bruno de Arruda Bravim ◽  
Marinês Dalla Valle Martino ◽  
Luci Correa ◽  
...  

Objective.To evaluate hand hygiene compliance in 2 adult step-down units (SDUs).Design.A 6-month (from March to September 2007), controlled trial comparing 2 SDUs, one with a feedback intervention program (ie, the intervention unit) and one without (ie, the control unit).Setting.Two 20-bed SDUs at a tertiary care private hospital.Methods.Hand hygiene episodes were measured by electronic recording devices and periodic observational surveys. In the intervention unit, feedback was provided by the SDU nurse manager, who explained twice a week to the healthcare workers the goals and targets for the process measures.Results.A total of 117,579 hand hygiene episodes were recorded in the intervention unit, and a total of 110,718 were recorded in the control unit (P= .63). There was no significant difference in the amount of chlorhexidine used in the intervention and control units (34.0 vs 26.7 L per 1,000 patient-days;P= .36) or the amount of alcohol gel used (72.5 vs 70.7 L per 1,000 patient-days;P= .93). However, in both units, healthcare workers used alcohol gel more frequently than chlorhexidine (143.2 vs 60.7 L per 1,000 patient-days;P< .001). Nosocomial infection rates in the intervention and control units, respectively, were as follows: for bloodstream infection, 3.5 and 0.79 infections per 1,000 catheter-days (P= .18); for urinary tract infection, 15.8 and 15.7 infections per 1,000 catheter-days (P= .99); and for tracheostomy-associated pneumonia, 10.7 and 5.1 infections per 1,000 device-days (P= . 13). There were no cases of infection with vancomycin-resistant enterococci and only a single case of infection with methicillin-resistantStaphylococcus aureus(in the control unit).Conclusions.The feedback intervention regarding hand hygiene had no significant effect on the rate of compliance. Other measures must be used to increase and sustain the rate of hand hygiene compliance.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Adele Brunetti ◽  
Francesca Macedonio ◽  
Giuseppe Barbieri ◽  
Enrico Drioli

Abstract The recent roadmap of SPIRE initiative includes the development of “new separation, extraction and pre-treatment technologies” as one of the “key actions” for boosting sustainability, enhancing the availability and quality of existing resources. Membrane condenser is an innovative technology that was recently investigated for the recovery of water vapor for waste gaseous streams, such as flue gas, biogas, cooling tower plumes, etc. Recently, it has been also proposed as pre-treatment unit for the reduction and control of contaminants in waste gaseous streams (SOx and NOx, VOCs, H2S, NH3, siloxanes, halides, particulates, organic pollutants). This perspective article reports recent progresses in the applications of the membrane condenser in the treatment of various gaseous streams for water recovery and contaminant control. After an overview of the operating principle, the membranes used, and the main results achieved, the work also proposes the role of this technology as pre-treatment stage to other separation technologies. The potentialities of the technology are also discussed aspiring to pave the way towards the development of an innovative technology where membrane condenser can cover a key role in redesigning the whole upgrading process.


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