Suburban growth controls and the price of new housing

The effect of Petaluma, California's growth control program on new house prices is examined by a comparative (quasi-experimental) design, using statistical controls. The difference in price increases between Petaluma and two comparison cities is calculated for houses of standard quality and for average actual houses in each city. It was found that prices of standard quality houses increased significantly more in Petaluma than in one of the comparison cities but not the other. A similar pattern was observed for actual houses. Reasons for the observed results and specific causes of the growth control effect are analyzed.     

The use of ultraviolet germicidal irradiation (UVGI) in disinfection of airborne bacteria

Contamination of indoor air by microbial pollutants has been increasingly recognized as a public health problem, and may be responsible for building-related illness (BRI) and sick-building syndrome (SBS). Bioaerosols such as fungi, bacteria, and viruses in indoor air can cause allergic and irritant responses, infectious diseases, respiratory problems, and hypersensitivity reactions. People sensitive to indoor environmental problems complain of a wide variety of symptoms ranging from headache, fatigue, nausea, sinus congestion, to eye, nose, and throat irritations.Although ultraviolet germicidal irradiation (UVGI) with a predominant wavelength of 254 nm has been used for air disinfection for many years to minimize microbial numbers in the air, few quantitative data are available on the radiation susceptibilities of individual airborne microbes. There have been a number of UVGI studies documenting the effectiveness of UVGI for the control of microbes in controlled settings. Many of these studies documented the effectiveness of UVGI against airborne tuberculosis organisms.The studies described here used commercial type fan-powered shielded UVGI-containing fixtures to evaluate their effectiveness in air disinfection. Aerosolization tests were done in the contained environment of a negative pressure bioaerosol stainless steel testing chamber 0.75 m wide·3.7 m long. The chamber was designed so that microbes could be safely aerosolized and contained while traversing the chamber through the UVGI-containing fix-tures. Four commercial (Purair UV Germicidal Systems, Mount Vernon, N.Y.) fan-powered UVGI-containing fix-tures placed in the chamber were individually evaluated for their ability to disinfect individual bioaerosols of air-borne bacteria.Air samples were taken at the inlet and outlet of the UVGI-containing units positioned in the bioaerosol chamber, using Ace Glass all-glass impingers (AGI-30). Five bacterial species were individually aerosolized to evaluate their kill. The bacteria used to test all of the UVGI-containing units were vegetative cells of Escherichia coli, Micrococcus luteus, Pseudomonas fluorescens, Staphylococcus aureus, and endospores of Bacillus subtilis. Based upon the concentration of bioaerosols collected at the inlet and outlet of the fixtures tested, the total overall microbial kills for the four fixtures with the filters in place and the UVGI units on were more than 99% for all the airborne vegetative bacteria tested, and a mean of over 75% for the B. subtilis endospores.All of the fixtures were efficient in the kill of the test vegetative bacteria used, even the more UVGI-resistant M. luteus vegetative cells and endospores of B. subtilis. Units such as these may provide an economical way to supplement existing air cleaning procedures used in indoor environments, and to kill airborne bacteria effectively without human exposure to UV light.     

Transformation and adsorption of Fenamiphos, f. sulfoxide and f. sulfone in molokai soil and simulated movement with irrigation

The ban of commonly used soil fumigants, DBCP and EDB, for control of nematodes in pineapple fields has prompted investigations into a non-fumigant nematicide, fenamiphos (Nemacur^®). The transformation and adsorption in soil of fenamiphos and its transformation products, f. sulfoxide and f. sulfone were studied in the laboratory. Fenamiphos adsorption on soil exceeded that of f. sulfoxide and f. sulfone. F. sulfoxide, however, was the most persistent. A one-dimensional simulation model was used to assess the impact of transformation and adsorption on the mobility and distribution of fenamiphos and f. sulfoxide in soil. Simulated results showed that fenamiphos stayed in the topsoil and transformed rapidly to f. sulfoxide. Because of the persistence and mobility of f. sulfoxide, this metabolite leached rapidly and significant amounts remained in the soil. This suggests that for times exceeding three weeks, f. sulfoxide may be the dominant compound providing nematode control in drip-irrigated pineapple.     

Use of Project MOHAVE perfluorocarbon tracer data to evaluate source and receptor models

Project MOHAVE was a major monitoring, modeling, and data analysis study whose objectives included the estimation of the contributions of the Mohave Power Project (MPP) and other sources to visibility impairment in the southwestern United States, in particular at Grand Canyon National Park. A major element of Project MOHAVE was the release of perfluorocarbon tracers at MPP and other locations during 50-day summer and 30-day winter intensive study periods. Tracer data (from about 30 locations) were sequestered until several source and receptor models were used to predict tracer concentrations. None of the models was successful in predicting the tracer concentrations; squared correlation coefficients between predicted and measured tracer were all less than 0.2, and most were less than 0.1.     

Microbial degradation of usnic acid in the reindeer rumen

Reindeer (Rangifer tarandus) eat and utilize lichens as an important source of energy and nutrients in winter. Lichens synthesize and accumulate a wide variety of phenolic secondary compounds, such as usnic acid, as a defense against herbivores and to protect against damage by UV-light in solar radiation. We have examined where and to what extent these phenolic compounds are degraded in the digestive tract of the reindeer, with particular focus on usnic acid. Three male reindeer were given ad libitum access to a control diet containing no usnic acid for three weeks and then fed lichens ad libitum (primarily Cladonia stellaris) containing 9.1 mg/g DM usnic acid for 4 weeks. Usnic acid intake in reindeer on the lichen diet was 91–117 mg/kg BM/day. In spite of this, no trace of usnic acid or conjugates of usnic acid was found either in fresh rumen fluid, urine, or feces. This suggests that usnic acid is rapidly degraded by rumen microbes, and that it consequently is not absorbed by the animal. This apparent ability to detoxify lichen phenolic compounds may gain increased importance with future enhanced UV-B radiation expected to cause increased protective usnic acid/phenol production in lichens.     

Runoff Storage Potential of Drained Upland Depressions on the Des Moines Lobe of Iowa

We present estimates of the volumetric storage capacities of currently drained upland depressions and catchment depressional specific storage and runoff storage indices for the Des Moines Lobe of Iowa (DML‐IA) subregion of the Prairie Pothole Region of North America. Storage capacities were determined using hydrologically enforced Light Detection and Ranging‐derived digital elevation models, and a unique geoprocessing algorithm. Depressional specific storage was estimated for each 12‐digit Hydrologic Unit Code (HUC12) watershed in the region from total catchment‐specific depressional storage volume and catchment area. Runoff storage indices were calculated using catchment depressional specific storage values and estimates of the amount of rainfall likely to fall within each watershed during sub‐annual and 1‐, 2‐, 5‐, and 10‐year 24‐h events. The 173,171 identified drained depressions in the DML‐IA can store up to 903.5 Mm³ of runoff. Most of this capacity is in depressions located in the north of the region. Specific storage varies from nearly 109 mm in the younger landscapes to <10 mm in older more eroded areas. For 95% of the HUC12 watersheds comprising the region, depressional storage will likely be exhausted by rainfall‐derived runoff in excess of a 1‐year 24‐h event. Rainfall amounts greater than a 5‐year 24‐h event will exceed all available depressional storage. Therefore, the capacity of drained depressions in the DML‐IA to mitigate flooding resulting from infrequent, but large, storm events is limited.     

绿色消费在推动高质量发展中的作用

当前,中国经济正在从高速增长转向高质量发展,其中消费是拉动经济增长的主要动力,是推动高质量发展的重要动能。从中国整体绿色发展转型进程和状态看,不平衡不协调的问题比较突出,经济维度的绿色转型发展较快较好,社会维度相对滞后。因此,如何在社会生活和消费领域推动绿色转型是中国政府应关注和解决的重大关键问题。国合会2018年主题是“创新引领绿色新时代”,本项目作为“创新与可持续生产和消费”课题下的专题研究,将为国家生态文明建设战略部署下如何推动形成绿色生活方式和消费方式以及提升社会治理体系提供政策决策支持。     

Telomere dynamics in the Sydney rock oyster (<Emphasis Type="Italic">Saccostrea glomerata</Emphasis>): an investigation into the effects of age,tissue type,location and time of sampling

Telomere length has been purported as a biomarker for age and could offer a non-lethal method for determining the age of wild-caught individuals. Molluscs, including oysters and abalone, are the basis of important fisheries globally and have been problematic to accurately age. To determine whether telomere length could provide an alternative means of ageing molluscs, we evaluated the relationship between telomere length and age using the commercially important Sydney rock oyster (Saccostrea glomerata). Telomere lengths were estimated from tissues of known age individuals from different age classes, locations and at different sampling times. Telomere length tended to decrease with age only in young oysters less than 18 months old, but no decrease was observed in older oysters aged 2–4 years. Regional and temporal differences in telomere attrition rates were also observed. The relationship between telomere length and age was weak, however, with individuals of identical age varying significantly in their telomere length making it an imprecise age biomarker in oysters.     

Invasional meltdown: invader-invader mutualism facilitates a secondary invasion

In multiply invaded ecosystems, introduced species should interact with each other as well as with native species. Invader-invader interactions may affect the success of further invaders by altering attributes of recipient communities and propagule pressure. The invasional meltdown hypothesis (IMH) posits that positive interactions among invaders initiate positive population-level feedback that intensifies impacts and promotes secondary invasions. IMH remains controversial: few studies show feedback between invaders that amplifies their effects, and none yet demonstrate facilitation of entry and spread of secondary invaders. Our results show that supercolonies of an alien ant, promoted by mutualism with introduced honeydew-secreting scale insects, permitted invasion by an exotic land snail on Christmas Island, Indian Ocean. Modeling of land snail spread over 750 sites across 135 km2 over seven years showed that the probability of land snail invasion was facilitated 253-fold in ant supercolonies but impeded in intact forest where predaceous native land crabs remained abundant. Land snail occurrence at neighboring sites, a measure of propagule pressure, also promoted land snail spread. Site comparisons and experiments revealed that ant supercolonies, by killing land crabs but not land snails, disrupted biotic resistance and provided enemy-free space. Predation pressure on land snails was lower (28.6%), survival 115 times longer, and abundance 20-fold greater in supercolonies than in intact forest. Whole-ecosystem suppression of supercolonies reversed the probability of land snail invasion by allowing recolonization of land crabs; land snails were much less likely (0.79%) to invade sites where supercolonies were suppressed than where they remained intact. Our results provide strong empirical evidence for IMH by demonstrating that mutualism between invaders reconfigures key interactions in the recipient community. This facilitates entry of secondary invaders and elevates propagule pressure, propagating their spread at the whole-ecosystem level. We show that identification and management of key facilitative interactions in invaded ecosystems can be used to reverse impacts and restore resistance to further invasions.