SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Term

243

To review the evidence for the short term association between air pollution and stroke.

Concepts: Evidence-based medicine, Systematic review, Meta-analysis, Term, Finance

185

Whether introduced species invasions pose a major threat to biodiversity is hotly debated. Much of this debate is fueled by recent findings that competition from introduced organisms has driven remarkably few plant species to extinction. Instead, native plant species in invaded ecosystems are often found in refugia: patchy, marginal habitats unsuitable to their nonnative competitors. However, whether the colonization and extinction dynamics of these refugia allow long-term native persistence is uncertain. Of particular concern is the possibility that invasive plants may induce an extinction debt in the native flora, where persistence over the short term masks deterministic extinction trajectories. We examined how invader impacts on landscape structure influence native plant persistence by combining recently developed quantitative techniques for evaluating metapopulation persistence with field measurements of an invaded plant community. We found that European grass invasion of an edaphically heterogeneous California landscape has greatly decreased the likelihood of the persistence of native metapopulations. It does so via two main pathways: (i) decreasing the size of native refugia, which reduces seed production and increases local extinction, and (ii) eroding the dispersal permeability of the matrix between refugia, which reduces their connectivity. Even when native plant extinction is the deterministic outcome of invasion, the time to extinction can be on the order of hundreds of years. We conclude that the relatively short time since invasion in many parts of the world is insufficient to observe the full impact of plant invasions on native biodiversity.

Concepts: Plant, Ecology, Term, Extinction, Invasive species, Introduced species, Biogeography, Habitat fragmentation

177

Many promising technological innovations in health and social care are characterized by nonadoption or abandonment by individuals or by failed attempts to scale up locally, spread distantly, or sustain the innovation long term at the organization or system level.

Concepts: Health care, Economics, Term, Technology, Patent, Innovation, Economic growth

174

BACKGROUND: Mild traumatic brain injury (mTBI) secondary to blast exposure is the most common battlefield injury in Southwest Asia. There has been little prospective work in the combat setting to test the efficacy of new countermeasures. The goal of this study was to compare the efficacy of N-acetyl cysteine (NAC) versus placebo on the symptoms associated with blast exposure mTBI in a combat setting. METHODS: This study was a randomized double blind, placebo-controlled study that was conducted on active duty service members at a forward deployed field hospital in Iraq. All symptomatic U.S. service members who were exposed to significant ordnance blast and who met the criteria for mTBI were offered participation in the study and 81 individuals agreed to participate. Individuals underwent a baseline evaluation and then were randomly assigned to receive either N-acetyl cysteine (NAC) or placebo for seven days. Each subject was re-evaluated at 3 and 7 days. Outcome measures were the presence of the following sequelae of mTBI: dizziness, hearing loss, headache, memory loss, sleep disturbances, and neurocognitive dysfunction. The resolution of these symptoms seven days after the blast exposure was the main outcome measure in this study. Logistic regression on the outcome of ‘no day 7 symptoms’ indicated that NAC treatment was significantly better than placebo (OR = 3.6, p = 0.006). Secondary analysis revealed subjects receiving NAC within 24 hours of blast had an 86% chance of symptom resolution with no reported side effects versus 42% for those seen early who received placebo. CONCLUSION: This study, conducted in an active theatre of war, demonstrates that NAC, a safe pharmaceutical countermeasure, has beneficial effects on the severity and resolution of sequelae of blast induced mTBI. This is the first demonstration of an effective short term countermeasure for mTBI. Further work on long term outcomes and the potential use of NAC in civilian mTBI is warranted. TRIAL REGISTRATION: ClinicalTrials.gov NCT00822263.

Concepts: Brain, Medical terms, Traumatic brain injury, Effectiveness, Term, Post-concussion syndrome, Concussion, BLAST

167

Chronic pancreatitis (CP) is a common gastrointestinal illness, which affects the quality of life with substantial morbidity and mortality. The management includes medical, endoscopic and surgical approaches with the need for interaction between various specialties, calling for a concerted multidisciplinary approach. However, at the time of this publication, guidelines to establish care of these patients are lacking. This review provides the reader with a comprehensive overview of the studies summarizing the various treatment options available, including medical, surgical and endoscopic options. In addition, technological advances such as endoscopic retrograde cholangiopancreatogrophy, endoscopic shock wave lithotripsy and endoscopic ultrasound can now be offered with reasonable success for pancreatic decompression, stricture dilatation with stent placement, stone fragmentation, pseudocyst drainage, and other endoscopic interventions such as celiac plexus block for pain relief. We emphasize the endoscopic options in this review, and attempt to extract the most up to date information from the current literature. The treatment of CP and its complications are discussed extensively. Complications such as biliary strictures. pancreatic pseudocysts, and chronic pain are common issues that arise as long-term complications of CP. These often require endoscopic or surgical management and possibly a combination of approaches, however choosing amongst the various therapeutic and palliative modalities while weighing the risks and benefits, makes the management of CP challenging. Treatment goals should be not just to control symptoms but also to prevent disease progression. Our aim in this paper is to advocate and emphasize an evidence based approach for the management of CP and associated long term complications.

Concepts: Medicine, Pain, Pancreatic cancer, Term, Suffering, Pancreatic pseudocyst, Robert C. Merton, Celiac plexus

166

Animal home ranges may vary little in their size and location in the short term but nevertheless show more variability in the long term. We evaluated the degree of site fidelity of two groups of spider monkeys (Ateles geoffroyi) over a 10- and 13-year period, respectively, in the northeastern Yucatan peninsula, Mexico. We used the Local Convex Hull method to estimate yearly home ranges and core areas (defined as the 60% probability contour) for the two groups. Home ranges varied from 7.7 to 49.6 ha and core areas varied from 3.1 to 9.2 ha. We evaluated the degree of site fidelity by quantifying the number of years in which different areas were used as either home ranges or core areas. Large tracts were used only as home ranges and only for a few years, whereas small areas were used as either core area or home range for the duration of the study. The sum of the yearly core areas coincided partially with the yearly home ranges, indicating that home ranges contain areas used intermittently. Home ranges, and especially core areas, contained a higher proportion of mature forest than the larger study site as a whole. Across years and only in one group, the size of core areas was positively correlated with the proportion of adult males in the group, while the size of home ranges was positively correlated with both the proportion of males and the number of tree species included in the diet. Our findings suggest that spider monkey home ranges are the result of a combination of long-term site fidelity and year-to-year use variation to enable exploration of new resources.

Concepts: Time, Primate, Term, Atelidae, Home range, Spider monkey, Geoffroy's Spider Monkey, Black-headed Spider Monkey

152

This study investigated the shape of bone grafts and associations with upper limb function over the long term after free vascularized fibular head graft (FVFHG) for reconstruction of the proximal humerus after wide resection for bone sarcoma.

Concepts: Time, Grafting, Term, Upper limb, Long-Term Capital Management

141

The sorption of Ni(II) on a calcareous aridisol (CA) soil, one of the major soil types in northwestern China, was investigated using batch and extended X-ray absorption fine structure (EXAFS) approaches in a 0.01 mol/L NaClO4 solution at different pH values (6.0-10.0), temperatures (25-60 °C) and contact times (2-15 days). Under alkaline conditions, EXAFS analysis showed that the interatomic distances between Ni and O atoms (RNi-O) were approximately 2.04 Å with a typical coordination number (CN) of ~6.0 O atoms in the contact time range from 2 to 15 days. The RNi-Ni (~3.07 Å) suggested that the structure of the Ni(II) adsorbed on the CA soil was basically the same as that of Ni(OH)2(s), while the Ni-Al shell (RNi-Al ~3.16 Å) gradually formed and grew with the increasing contact time. Under weakly acidic conditions, the sorption mechanism of Ni(II) on the CA soil possibly included at least two processes: (i) a fast accumulation dominated by ion exchange and surface complexation and (ii) the formation of a Ni-Al LDH phase over the long term. A high temperature is beneficial to the fixation of Ni(II) on the CA soil and the formation of a Ni-Al LDH.

Concepts: Time, Electron, Hydrogen, Chemistry, Adsorption, PH, Term, Soil classification

106

Psoriasis is an immunodysregulatory inflammatory disease associated with comorbidities impacting quality of life. With the advent of new treatments, there is growing need to assess the long term safety and efficacy of treatments in a real-world setting.

Concepts: Term

91

Several meta-analyses have demonstrated the efficacy of psychological therapies for reducing gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS). However, no meta-analysis has investigated the duration of these effects. We performed a meta-analysis to assess the immediate, short-term, and long-term efficacy of psychotherapy for reducing GI symptoms in adults with IBS.

Concepts: Time, Systematic review, Gastroenterology, Educational psychology, Irritable bowel syndrome, Flatulence, Meta-analysis, Term