Underplanting degraded exotic Pinus with indigenous conifers assists forest restoration

We propose that nonharvest plantations could provide important opportunities for restoration of indigenous forest cover and related ecosystem services. We assessed the relative performance of three Podocarpaceae (podocarps) species planted into a degraded Ponderosa Pine (Pinus ponderosa) plantation, central North Island, New Zealand. We hypothesised that the degraded pine plantation overstorey could provide suitable conditions for the development of a podocarp‐dominated forest structure within ca. 50 years of underplanting and that podocarp growth would differ depending on the species suitability to the site. Rimu (Dacrydium cupressinum) significantly outperformed both Totara (Podocarpus totara) and Kahikatea (Dacrycarpus dacrydioides) in height and diameter growth. Rimu was now the structurally dominant tree where it occurred rather than pine. Per annum scaled carbon storage within Rimu stands was significantly greater than the Totara, Kahikatea or Pine stands. All podocarp species had attained a greater stand density compared to the pine overstorey. Possible reasons for the differing podocarp growth performance include different light requirements, response to soil nutrients, elevational distributions and frost susceptibility. There were significant differences in understorey species richness among the different stands of podocarp species. Underplanting accelerated successional development by incorporating late‐successional indigenous canopy dominants within the forest succession and overcame limitations imposed on forest succession at the site from its isolation from indigenous forest tree seed sources.     

Snag Benchmarks and Treatment Options for Mixed‐Pine Forest Restoration in Eastern Upper Michigan

Snags (dead‐standing trees) are biological legacies that remain after disturbances in forests. We enhanced the ecological underpinnings of snag management within the context of mixed‐pine forest restoration in the northern Lake States by quantifying characteristics of live trees and snags within eighty-five 500‐m² plots at Seney National Wildlife Refuge (NWR) in eastern Upper Michigan. Study plots represented reference conditions (i.e. no past harvesting, relatively unaltered fire regime) and altered (i.e. harvested, altered fire regime) conditions. We also compared three treatments for creating snags from live trees. Snags were found in 87% of the reference plots and 85% of the altered plots. The only snag variables that differed between plot types were mean snag basal area, which was greater in altered plots (Student's t‐test, p = 0.04), and mean percent total basal area of snags (greater in reference plots, p = 0.06). The composition of snags differed only in the 10‐ and 25‐cm diameter classes (Multi‐Response Permutation Procedure, p < 0.10). The percentage of snags that developed into the most advanced decay class (DC) differed among treatments after 4 years (χ² = 16.49, p < 0.01), with 26% of girdled trees, 3% of prescribed fire trees, and zero topped trees reaching DC5. Logistic regression illustrated that the influence of predictor variables on DC development varied by species and treatment. The findings from this study, past studies, and ongoing projects at Seney NWR are directly applicable to innovative management of snags in mixed‐pine forests.     

医院医技人员对流行区华支睾吸虫病认知状况的调查

目的调查医院医技人员对流行区华支睾吸虫病的认知状况,为该病防治策略的制定提供依据。方法从华支睾吸虫流行病学、临床表现与并发症、诊断和治疗及相关知识的获得途径这几方面设置调查问卷,总分19分。对佳木斯市5家综合性医院和1家传染病专科医院医技人员进行匿名问卷调查。结果共发放问卷340份,回收有效问卷334份,有效应答率98.24%。334名医技人员最低得分2分,最高得分17分,平均得分(11.38±3.50)分(正确率59.89%)。其中5家综合医院医技人员平均得分(10.84±3.27)分,1家传染病专科医院医技人员平均得分(15.78±1.73)分,二者差异有统计学意义(t=14.353,P<0.001)。高级职称医技人员在流行病学、临床表现与并发症、诊断与治疗方面的得分均高于其他职称医技人员(均P<0.05)。结论佳木斯地区医技人员华支睾吸虫病总体认知率不高,应对不同医疗机构和职称的医技人员制定相应的培训内容,鼓励医技人员多途径获取华支睾吸虫病相关知识。     

Circadian Phase,Sleepiness, and Light Exposure Assessment in Night Workers With and Without Shift Work Disorder

Most night workers are unable to adjust their circadian rhythms to the atypical hours of sleep and wake. Between 10% and 30% of shiftworkers report symptoms of excessive sleepiness and/or insomnia consistent with a diagnosis of shift work disorder (SWD). Difficulties in attaining appropriate shifts in circadian phase, in response to night work, may explain why some individuals develop SWD. In the present study, it was hypothesized that disturbances of sleep and wakefulness in shiftworkers are related to the degree of mismatch between their endogenous circadian rhythms and the night-work schedule of sleep during the day and wake activities at night. Five asymptomatic night workers (ANWs) (3 females; [mean?±?SD] age: 39.2?±?12.5 yrs; mean yrs on shift?=?9.3) and five night workers meeting diagnostic criteria (International Classification of Sleep Disorders [ICSD]-2) for SWD (3 females; age: 35.6?±?8.6 yrs; mean years on shift?=?8.4) participated. All participants were admitted to the sleep center at 16:00?h, where they stayed in a dim light (<10 lux) private room for the study period of 25 consecutive hours. Saliva samples for melatonin assessment were collected at 30-min intervals. Circadian phase was determined from circadian rhythms of salivary melatonin onset (dim light melatonin onset, DLMO) calculated for each individual melatonin profile. Objective sleepiness was assessed using the multiple sleep latency test (MSLT; 13 trials, 2-h intervals starting at 17:00?h). A Mann-Whitney U test was used for evaluation of differences between groups. The DLMO in ANW group was 04:42?±?3.25?h, whereas in the SWD group it was 20:42?±?2.21?h (z = 2.4; p?<?.05). Sleep did not differ between groups, except the SWD group showed an earlier bedtime on off days from work relative to that in ANW group. The MSLT corresponding to night work time (01:00–09:00?h) was significantly shorter (3.6?±?.90?min: [M?±?SEM]) in the SWD group compared with that in ANW group (6.8?±?.93?min). DLMO was significantly correlated with insomnia severity (r = ?.68; p < .03), indicating that the workers with more severe insomnia symptoms had an earlier timing of DLMO. Finally, SWD subjects were exposed to more morning light (between 05:00 and 11:00?h) as than ANW ones (798 vs. 180 lux [M?±?SD], respectively z?=??1.7; p?<?.05). These data provide evidence of an internal physiological delay of the circadian pacemaker in asymptomatic night-shift workers. In contrast, individuals with SWD maintain a circadian phase position similar to day workers, leading to a mismatch/conflict between their endogenous rhythms and their sleep-wake schedule. (Author correspondence: vgumeny1@hfhs.org)     

Sleep Parameters among Offshore Workers: An Initial Assessment in the Campos Basin,Rio De Janeiro,Brazil

Shift work has potentially adverse effects on health, particularly on sleep. The purpose of the present study was to assess sleep parameters among personnel working in oil and gas offshore installations in the Campos Basin, Rio de Janeiro, Brazil. One hundred and seventy-nine subjects were asked to complete a sleep questionnaire with multiple-choice answers. Offshore workers were divided into two groups according to their work schedule: (1) fixed daytime workers (n = 86; age: 35.8 ± 9.6 yrs) and (2) shift (n = 87) or night (n = 6) workers (total n = 93; age: 37.7 ± 9.7 yrs). Shift/night workers reported poor sleep more frequently than the daytime workers (20.4% vs. 1.2%, p < 0.01), as well as habitual difficulty in falling asleep (15.1% vs. 4.7%, p < 0.01), long latency of sleep onset (28% vs. 7%, p < 0.01), fragmented sleep (45.2% vs. 16.3%, p < 0.01), short sleep episodes (44.1% vs. 16.3%, p < 0.01), irregular bedtimes (29.0% vs. 12.8%, p < 0.01), and feeling tired upon awakening (15.1% vs. 3.5%, p < 0.01). Habitual napping and loud snoring were reported twice as often in shift/night than in day workers (p < 0.01). Nightmares, somnambulism, and unpleasant feeling in the legs were equality reported by both groups (p > 0.05). Few offshore workers had sought medical help for their sleep problems. A higher number of shift/night workers reported feelings of sadness compared with day workers (26.9% vs. 9.3%, p < 0.01). The findings of this study show that subjective reports of sleep-related problems are quite common among Brazilian offshore shift workers. Reliance on self-reported sleep problems and a cross-sectional design are the main limitations of our study.     

A Reliability and Validity Study of the Bergen Shift Work Sleep Questionnaire in Nurses Working Three-Shift Rotations

The “Bergen Shift Work Sleep Questionnaire” (BSWSQ) was developed to systematically assess discrete sleep problems related to different work shifts (day, evening, night shifts) and rest days. In this study, we assessed the psychometric properties of the BSWSQ using a sample of 760 nurses, all working in a three-shift rotation schedule: day, evening, and night shifts. BSWSQ measures insomnia symptoms using seven questions: >30-min sleep onset latency, >30-min wake after sleep onset, >30-min premature awakenings, nonrestorative sleep, being tired/sleepy at work, during free time on work days, and when not working/on vacation. Symptoms are assessed separately for each work shift and rest days, as “never,” “rarely,” “sometimes,” “often,” “always,” or “not applicable.” We investigated the BSWSQ model fit, reliability (test-retest of a subsample, n?=?234), and convergent and discriminant validity between the BSWSQ and Epworth Sleepiness Scale, Fatigue Questionnaire, and Hospital Anxiety Depression Scale. We also investigated differences in mean scores between the different insomnia symptoms with respect to different work shifts and rest days. BSWSQ demonstrated an adequate model fit using structural equation modeling: root mean square error of approximation?=?.071 (90% confidence interval [CI]?=?.066–.076), comparative fit index?=?.91, and chi-square/degrees of freedom?=?4.41. The BSWSQ demonstrated good reliability (test-retest coefficients p?<?.001). We found good convergent and discriminant validity between BSWSQ and the other scales (all coefficients p?<?.001). There were significant differences between the overall/composite scores of the various work shifts. Night shift showed the highest score compared to day and evening shifts as well as to rest days (all post hoc comparisons p?<?.001). Mean scores of different symptoms also varied significantly within the individual work shifts. We conclude that the BSWSQ meets the necessary psychometric standards, enabling systematic study of discrete insomnia symptoms in different work shifts. (Author correspondence: elisabeth.flo@psykp.uib.no)     

Fungal species diversity in juvenile and adult leaves of Eucalyptus globulus from plantations affected by Mycosphaerella leaf disease

In recent years, Mycosphaerella leaf disease (MLD) has become very common in Eucalyptus globulus plantations in Galicia, northwest Spain. The aetiology of MLD is complex and is associated with several species of Mycosphaerella and Teratosphaeria. A survey of the fungal mycobiota associated with juvenile and adult leaves and with leaf litter of the same trees in MLD‐affected plantations was made. The goal was to identify pathogens and endophytes, to determine whether the mycobiota of each leaf type differed and whether leaf litter might be a reservoir of MLD inoculum. Fungi belonging to 113 different species were isolated from the leaves of juvenile and adult trees sampled at 10 locations; 81 species occurred in juvenile and 65 in adult leaves. The average number of species obtained from juvenile leaves was significantly greater (P > 0.01) compared to adult leaves. This difference suggested that juvenile leaves are not only more susceptible to a group of pathogens, but to a wide range of fungi. Therefore, a general resistance mechanism might be lacking or be less effective in juvenile than in adult leaves. Several pathogenic species were identified in both leaf types. Leaf litter and living leaf mycobiotas were very different. However, some of the species they shared were MLD pathogens, suggesting that leaf litter could contribute to the inoculum of MLD.     

Factors contributing to carbon fluxes from bioenergy harvests in the U.S. Northeast: an analysis using field data

With growing interest in wood bioenergy there is uncertainty over greenhouse gas emissions associated with offsetting fossil fuels. Although quantifying postharvest carbon (C) fluxes will require accurate data, relatively few studies have evaluated these using field data from actual bioenergy harvests. We assessed C reductions and net fluxes immediately postharvest from whole‐tree harvests (WTH), bioenergy harvests without WTH, and nonbioenergy harvests at 35 sites across the northeastern United States. We compared the aboveground forest C in harvested with paired unharvested sites, and analyzed the C transferred to wood products and C emissions from energy generation from harvested sites, including indirect emissions from harvesting, transporting, and processing. All harvests reduced live tree C; however, only bioenergy harvests using WTH significantly reduced C stored in snags (P < 0.01). On average, WTH sites also decreased downed coarse woody debris C while the other harvest types showed increases, although these results were not statistically significant. Bioenergy harvests using WTH generated fewer wood products and resulted in more emissions released from bioenergy than the other two types of harvests, which resulted in a greater net flux of C (P < 0.01). A Classification and Regression Tree analysis determined that it was not the type of harvest or amount of bioenergy generated, but rather the type of skidding machinery and specifics of silvicultural treatment that had the largest impact on net C flux. Although additional research is needed to determine the impact of bioenergy harvesting over multiple rotations and at landscape scales, we conclude that operational factors often associated with WTH may result in an overall intensification of C fluxes. The intensification of bioenergy harvests, and subsequent C emissions, that result from these operational factors could be reduced if operators select smaller equipment and leave a portion of tree tops on site.     

Stochastic multiplicative population growth predicts and interprets Taylor's power law of fluctuation scaling

Taylor''s law (TL) asserts that the variance of the density (individuals per area or volume) of a set of comparable populations is a power-law function of the mean density of those populations. Despite the empirical confirmation of TL in hundreds of species, there is little consensus about why TL is so widely observed and how its estimated parameters should be interpreted. Here, we report that the Lewontin–Cohen (henceforth LC) model of stochastic population dynamics, which has been widely discussed and applied, leads to a spatial TL in the limit of large time and provides an explicit, exact interpretation of its parameters. The exponent of TL exceeds 2 if and only if the LC model is supercritical (growing on average), equals 2 if and only if the LC model is deterministic, and is less than 2 if and only if the LC model is subcritical (declining on average). TL and the LC model describe the spatial variability and the temporal dynamics of populations of trees on long-term plots censused over 75 years at the Black Rock Forest, Cornwall, NY, USA.