Evaluating bubble chain phenomena as a mechanism for open system degassing in basaltic systems

Passive degassing – i.e., the open-system degassing of a magmatic gas phase that is decoupled from the melt phase – is common at many basaltic volcanic systems and consistently makes a greater contribution to total volcanic gas emissions than eruptive degassing. However, the mechanism for passive degassing is not fully understood. We investigate the feasibility of permeable gas flow through connected bubbles or pathways using experiments with aqueous solutions of hydroxyethyl cellulose (HEC), a non-Newtonian analogue material for magma. Stable chains of connected bubbles have previously been reported in similar non-Newtonian polymer solutions. We observe a range of bubble chain phenomena and identified five regimes, numbering in order of increasing gas flow rate: 1) small individual bubbles; 2) chains of rounded bubbles; 3) chains of elongate bubbles; 4) pipe-like ‘winding flue’; 5) large individual bubbles. The bubble chain phenomena (regimes 2–4) are observed over a restricted interval of gas flow rates. We determine the rheology of the solutions and conclude that the HEC solutions that produced bubble chain phenomena in our experiments are well scaled to shear-thinning and viscoelastic magmas, hence bubble chain phenomena could form in magmas. Our analysis also suggests that the viscoelastic rheology of HEC plays a fundamental role in the observed bubble chain phenomena

Coordinated and tailored work rehabilitation: a randomized controlled trial with economic evaluation undertaken with workers on sick leave due to musculoskeletal disorders

Introduction In Denmark, the magnitude and impact of work disability on the individual worker and society has prompted the development of a new "coordinated and tailored work rehabilitation" (CTWR) approach. The aim of this study was to compare the effects of CTWR with conventional case management (CCM) on return-to-work of workers on sick leave due to musculoskeletal disorders (MSDs). Methods The study was a randomized controlled trial with economic evaluation undertaken with workers on sick leave for 4-12 weeks due to MSDs. CTWR consists of a work disability screening by an interdisciplinary team followed by the collaborative development of a RTW plan. The primary outcome variable was registered cumulative sickness absence hours during 12 months follow-up. Secondary outcomes were work status as well as pain intensity and functional disability, measured at baseline, 3 and 12 months follow-up. The economic evaluation (intervention costs, productivity loss, and health care utilization costs) was based on administrative data derived from national registries. Results For the time intervals 0-6 months, 6-12 months, and the entire follow-up period, the number of sickness absence hours was significantly lower in the CTWR group as compared to the control group. The total costs saved in CTWR participants compared to controls were estimated at US $1,366 per person at 6 months follow-up and US$ 10,666 per person at 12 months follow-up. Conclusions Workers on sick leave for 4-12 weeks due to MSD who underwent "CTWR" by an interdisciplinary team had fewer sickness absence hours than controls. The economic evaluation showed that-in terms of productivity loss-CTWR seems to be cost saving for the society

Ecological resilience of restored peatlands to climate change

This is the final version. Available from Nature Research via the DOI in this record. Degradation of peatlands through land-use change and drainage is currently responsible for 5-10% of global annual anthropogenic carbon dioxide emissions. Therefore, restoring disturbed and degraded peatlands is an emerging priority in efforts to mitigate climate change. While restoration can revive multiple ecosystem functions, including carbon storage, the resilience of restored peatlands to climate change and other disturbances remains poorly understood. Here, we review the recent literature on the response of degraded and restored peatlands to fire, drought and flood. We find that degraded sites can generally be restored in a way that allows for net carbon sequestration. However, biodiversity, hydrological regime, and peat soil structure are not always fully restored, even after a decade of restoration efforts, potentially weakening ecosystem resilience to future disturbances. As the recovery of degraded peatlands is fundamental to achieving net-zero goals and biodiversity targets, sound science and monitoring efforts are needed to further inform restoration investments and priorities

Conformational changes of polymers in model batter systems

Cake batters - made of flour, egg, sugar and fat - are complex systems. Ingredients interactions and their impact on protein secondary structure and starch conformational structures were studied in model batter systems using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. The results showed the possibility of using the pregelatinized starch without affecting protein conformation. The estimation of protein secondary structure highlighted the prevalence of \u3b1-helical structures in the model batter system, while \u3b2-sheets are predominant in flour systems as known in dough systems. The protein conformation in batter system is related to fat-protein interactions and could explain fat functionality in the final product. Starch crystallinity increased when each ingredient - except for pregelatinized starches - was added to the flour. Changes in starch conformation could be related to the redistribution of water between the batter ingredients. The overall results highlighted the importance of ingredients on the structural conformation of the batter polymers - starch and proteins - which could be the key factor to understand the functional properties of the batter

The Force-Velocity Relation for Growing Biopolymers

The process of force generation by the growth of biopolymers is simulated via a Langevin-dynamics approach. The interaction forces are taken to have simple forms that favor the growth of straight fibers from solution. The force-velocity relation is obtained from the simulations for two versions of the monomer-monomer force field. It is found that the growth rate drops off more rapidly with applied force than expected from the simplest theories based on thermal motion of the obstacle. The discrepancies amount to a factor of three or more when the applied force exceeds 2.5kT/a, where a is the step size for the polymer growth. These results are explained on the basis of restricted diffusion of monomers near the fiber tip. It is also found that the mobility of the obstacle has little effect on the growth rate, over a broad range.Comment: Latex source, 9 postscript figures, uses psfig.st

Bilan de la flore de la région de Tlemcen (Oranie-Algérie)

Dans l'ouest algérien, le sort des formations végétales n'a pas échappé à l'action dévastatrice de l'homme. Les écosystèmes forestiers et préforestiers voire steppiques de la région de Tlemcen ont subi d'énormes modifications, dues principalement à l'impact conjugué de l'homme et du climat

High prevalence of Lynx rufus gammaherpesvirus 1 in wild Vermont bobcats

Gammaherpesviruses (GHVs) are host specific DNA viruses that infect a large range of mammalian species. These viruses preferentially target host lymphocyte cell populations and infection may lead to morbidity or mortality in immunocompromised, co-infected, or non-adapted hosts. In this study, we tested for the presence of Lynx rufus gammaherpesvirus 1 (LruGHV1) in a northeastern United States population of wild bobcats (L. rufus). We estimated prevalence of infection and viral load in infected individuals using quantitative real-time PCR analysis of spleen DNA from 64 Vermont bobcats. We observed an overall prevalence of 64% using this methodology. Bobcat age was significantly positively associated with GHV infection status, and we noted a trend for higher viral loads in young animals, but prevalence and viral load were similar in male and female bobcats. A single LruGHV1 variant was identified from the sequencing of the viral glycoprotein B gene of Vermont bobcats. This gene sequence was 100% similar to that reported in Florida bobcats and slightly variant from other isolates identified in the Western USA. Our work suggests broad geographic distribution and high prevalence of LruGHV1 in bobcat populations across the United States with infection attributes that suggest horizontal transmission of the agent. Geographic differences in viral genotype may reflect historical migration and expansion events among bobcat populations

In Utero Diagnosis of Niemann-Pick Type C in the Absence of Family History

Niemann-Pick type C (NPC) disease is a recessive disorder that results in unesterified cholesterol accumulating in the lysosomal and late endosomal system. It is caused by mutations in NPC1 or NPC2 genes and leads to systemic and neurodegenerative symptoms. Few cases of prenatal presentation of NPC have been reported and only two cases in the absence of previous family history, indicating the diagnosis is particularly difficult in such a situation. We report a prenatal diagnosis of NPC in a couple without family history. An ultrasound screening at 22 weeks of gestation (WG) detected fetal ascites and hepatomegaly, which were still present at 25, 27, and 29 WG, and a splenomegaly progressively appeared. No placentomegaly or other signs of hydrops fetalis were observed. The diagnostic of NPC was prenatally confirmed by a filipin test and NPC1 sequencing and multiplex ligation-dependent probe amplification assay which revealed a maternal missense mutation (c.2608T>C; p.Ser870Pro) and a paternal deletion of exons 5 to 25. This additional prenatal case of NPC suggests that even in the absence of family history, fetal ascites associated with splenomegaly but no hydrops should nonetheless arouse suspicion concerning this disease as a possible diagnosis