816 research outputs found
Hydrologic indicators of hot spots and hot moments of mercury methylation potential along river corridors
The authors acknowledge financial support from the National Science Foundation: EAR-1226741 (to M.B.S.) and EAR-1225630 (to J.D.B.), and from the REG Trust (to M.B.S.).The biogeochemical cycling of metals and other contaminants in river-floodplain corridors is controlled by microbial activity responding to dynamic redox conditions. Riverine flooding thus has the potential to affect speciation of redox-sensitive metals such as mercury (Hg). Therefore, inundation history over a period of decades potentially holds information on past production of bioavailable Hg. We investigate this within a Northern California river system with a legacy of landscape-scale 19th century hydraulic gold mining. We combine hydraulic modeling, Hg measurements in sediment and biota, and first-order calculations of mercury transformation to assess the potential role of river floodplains in producing monomethylmercury (MMHg), a neurotoxin which accumulates in local and migratory food webs. We identify frequently inundated floodplain areas, as well as floodplain areas inundated for long periods. We quantify the probability of MMHg production potential (MPP) associated with hydrology in each sector of the river system as a function of the spatial patterns of overbank inundation and drainage, which affect long-term redox history of contaminated sediments. Our findings identify river floodplains as periodic, temporary, yet potentially important, loci of biogeochemical transformation in which contaminants may undergo change during limited periods of the hydrologic record. We suggest that inundation is an important driver of MPP in river corridors and that the entire flow history must be analyzed retrospectively in terms of inundation magnitude and frequency in order to accurately assess biogeochemical risks, rather than merely highlighting the largest floods or low-flow periods. MMHg bioaccumulation within the aquatic food web in this system may pose a major risk to humans and waterfowl that eat migratory salmonids, which are being encouraged to come up these rivers to spawn. There is a long-term pattern of MPP under the current flow regime that is likely to be accentuated by increasingly common large floods with extended duration.PostprintPeer reviewe
Are prices of new dwellings different? A spectral analysis of UK property vintages
The work makes two contributions to Hui’s (2011) dynamic house price classification. First, a house price ripple in cycles from Modern to Older dwellings is revealed and, second, as New housing is shown to have lower volatility than the other two. Using spectral analysis, it is argued that there is a 7½-year repeat buyer-second-hand cycle and a five year, first time buyer-New housing cycle, common to three house price vintages. These cycles reinforce each other every fifteen years, which corresponds with a Minsky super-cycle in housing finance.
The equity of the owner-occupier is fortified by higher house prices whereas new builds extract embedded equity from the market. Government should support builders and facilitate access to market to first time buyers and through programmes like Help-to-Buy 1. However, to address the greater price instability that should follow, Government should impose a capital gains tax on the house seller
Is Low-Level Laser Therapy Effective for Pain Reduction in Patients with Chronic Low Back Pain?
OBJECTIVE: The objective of this selective EBM review is to determine whether or not lowlevel laser therapy is effective for pain reduction in patients with chronic low back pain.
STUDY DESIGN: Two randomized controlled trials published in 2010 and 2017 and one nonrandomized placebo-controlled clinical trial published in 2018.
DATA SOURCES: Sources were written in English and published in peer-reviewed journal articles comparing low-level laser therapy (LLLT) to groups consisting of a combined laser therapy regimen or placebo in patients with chronic low back pain, found using PubMed.
OUTCOMES MEASURED: Low back pain was assessed using the visual analog scale (VAS). The statistics used to assess significance of the outcome measured were P-values, change in mean from baseline, and SD.
RESULTS: The first study (Ay S, Doğan Ş, Evcik D. J Back Musculoskelet Rehabil. 2017;30(2):235-240. doi: 10.3233/BMR-160739) compared two treatment groups who received LLLT for the treatment of chronic low back pain (CLBP). Improvements in pain were statistically significant in both groups (p-value \u3c0.01), but no difference was found between the two LLLT regimens. Another study (Ay S, Doğan Ş, Evcik D. Clin Rheumatol. 2010;29(8):905- 910. doi: 10.1007/s10067-010-1460-0) compared LLLT vs placebo in patients with CLBP, in addition to analyzing LLLT vs placebo in acute pain management. A statistically significant improvement in pain severity (p-value \u3c0.001) was observed in LLLT and placebo groups for CLBP. A third study (Taradaj J, Rajfur K, Shay B, et al. Clin Interv Aging. 2018;13:1445- 1455. doi: 10.2147/CIA.S168094) again compared LLLT to placebo for CLBP, in addition to analyzing high-intensity laser therapy (HILT) to placebo. In the LLLT and LLLT sham groups, a statistically significant (p\u3c0.01) decrease in pain was noted.
CONCLUSION: These results superficially indicate that LLLT is an effective means of reducing pain associated with CLBP. However, comparison between sham groups and actual treatment groups seem to suggest a significant influence of placebo in the efficacy of LLLT. This evidence suggests that the general experience of undergoing laser therapy is what causes a reduction of pain, rather than science behind the laser therapy itself. The evidence provided is therefore not sufficient enough to support the claim that LLLT is an effective, appropriate or advisable treatment of CLBP. Future studies should directly compare the statistical difference in decreased pain scores between LLLT and placebo alone
Explaining spatial variation in housing construction activity in Turkey
In Turkey, there has been a strong policy narrative that has emphasized the importance of construction activity as a driver of economic growth. This has given shape to a central state-led policy regime that has sought to ensure that planners and other urban policy makers develop plans and strategies that support construction activity. Against this backdrop, and a recent history of uneven spatial development, this paper seeks to understand what this policy imperative might mean for housing construction activity in different provinces. It seeks to reflect on both the relationship between the state and the market, and the interaction between state policies, economic drivers and levels of construction activity. The evidence presented in the paper suggests that uneven spatial development might be explained in different ways in different provinces. Although, in many cases, patterns of construction activity are consistent with economic fundamentals, there are important exceptions in some regions where arguably activity levels are at odds with prior expectations
Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining
The authors acknowledge financial support from the National Science Foundation: EAR-1226741 (to M.B.S.) and EAR-1225630 (to J.D.B.).Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ202Hg and Δ199Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870 ng/g) and δ202Hg (− 1.69 to − 0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ202Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ202Hg and Δ199Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ202Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ202Hg) of at least − 0.4‰ whereas Yolo Bypass had MDF of + 0.2 to + 0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (− MDF) is unique compared to + MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean.PostprintPeer reviewe
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Harmony Or Discord: Disordered Eating and Personality Traits of College Music Majors
Personality traits, such as neuroticism, perfectionism, and a narrow self-concept have been identified as risk factors for eating disorders or have been found at higher rates in those with eating disorders (e.g., Brannan & Petrie, 2008; Cash & Deagle, 1997; Cervera et al., 2003). Musicians exhibit many of these personality traits associated with eating disorders (e.g., Kemp, 1981), however eating disorder prevalence has not been studied in musicians. The present study examined the prevalence of eating disorders and pathogenic weight control behaviors among college music majors. This study also compared personality traits (i.e., neuroticism, perfectionism, musician identity) between music majors and nonmajors and examined which personality traits best predicted bulimic symptomatology. Participants were 93 female and 126 male undergraduate students majoring in music and a nonmusician comparison group of 310 women 140 men from the same university. Music majors and nonmajors did not differ from each other with regards to eating disorder prevalence rates. Exercising and fasting/strict dieting were the primary means of weight control amongst all participants. With regards to personality traits, female and male music majors reported higher levels of perfectionism than their nonmajor counterparts and male music majors reported higher levels of neuroticism than male nonmajors. After controlling for BMI, neuroticism and doubts about actions predicted bulimic symptoms in female music majors, whereas concern over mistakes predicted bulimic symptomatology among men majoring in music. Findings suggest that any additional appearance-based pressures from the music environment do not translate into increased levels of eating pathology. Music majors higher levels of perfectionism and neuroticism may help them to succeed within the music and perform at a high level. Lastly, personality dimensions of neuroticism and concern over making mistakes predict disordered eating in all students
4-Chloro-7-hydroxy-6-methyl-1,7-naphthyridin-8(7H)-one
The title compound, C9H7ClN2O2, was prepared by reaction of methyl 4-chloro-3-(prop-1-ynyl)picolinate with hydroxylamine in MeOH/KOH solution. The two essentially planar molecules which make up the asymmetric unit have almost identical geometries and and are linked into dimeric aggregates via pairs of O—H⋯O hydrogen bonds. These aggregates have almost perfect inversion symmetry; however, quite unusually, the inversion center of the dimer does not coincide with the crystallographic inversion center
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