An upgrade of the primary length standard of Republic of Serbia where digital stabilization is performed by Arduino Due board.

An upgrade of the electronic system for frequency stabilization of the HeNe laser, primary length standard of Republic of Serbia, based on digital electronics, is described. Arduino microcontrollers have been used for stabilization, and laptop computer has been used only to communicate with the user. In addition, an analog electronics has been developed in order to boost the performance of the setup. The setup is simple and inexpensive, made of off-the-shelf electronics components. Despite this, good performances have been achieved.

Geometry of turbulent dissipation and the Navier-Stokes regularity problem.

The question of whether a singularity can form in an initially regular flow, described by the 3D incompressible Navier-Stokes (NS) equations, is a fundamental problem in mathematical physics. The NS regularity problem is super-critical, i.e., there is a 'scaling gap' between what can be established by mathematical analysis and what is needed to rule out a singularity. A recently introduced mathematical framework-based on a suitably defined 'scale of sparseness' of the regions of intense vorticity-brought the first scaling reduction of the NS super-criticality since the 1960s. Here, we put this framework to the first numerical test using a spatially highly resolved computational simulation performed near a 'burst' of the vorticity magnitude. The results confirm that the scale is well suited to detect the onset of dissipation and provide numerical evidence that ongoing mathematical efforts may succeed in closing the scaling gap.

Search for topological defect dark matter with a global network of optical magnetometers.

Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared with the Galaxy but much larger than the Earth. Here we report the results of the search for transient signals from the domain walls of axion-like particles by using the global network of optical magnetometers for exotic (GNOME) physics searches. We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of these data from a continuous month-long operation of GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios.

Efficacy and safety of once monthly ibandronate treatment in patients with reduced bone mineral density--ESTHER study.

INTRODUCTION: Osteoporosis usually affects post-menopausal women. Treatment is individualized and requires an approach that will provide long-term compliance to prevent fractures. Studies conducted so far suggest inadequate compliance and persistence in weekly bisphosphonate treatment (under 43% after a year of treatment). Ibandronate, as a powerful bisphosphonate, has made it possible for the first time to treat osteoporosis with a single tablet per month. OBJECTIVE: Study of efficacy, safety and tolerance of ibandronate applied once a month in female patients with decreased bone mineral density (BMD). METHODS: The prospective study was conducted in 34 centres in Serbia covering the total of 370 women with reduced BMD with ibandronate once a month. Demographic data, risk factors for osteoporosis, mode of diagnosis establishment, previous treatment for osteoporosis and concomitant diseases were investigated. Efficacy of the treatment was evaluated by T-score value after 12 months versus the baseline values. Tolerance of the treatment, compliance and adverse effects were recorded. RESULTS: The sample included 97.5% post-menopausal women, 92.7% with osteoporosis. In 80% of the cases, the diagnosis was established by DXA measurement. In more than 90% of the sample, the level of physical activity was unsatisfactory, and 70% had an accompanying risk factor for osteoporosis in addition to menopause. After 12 months of treatment, 100% compliance was recorded in 84% of the patients and significant reduction (p < 0.0001) of the bone mineral loss, regardless of the previous aminobisphosphonate treatment. The treatment was tolerated well, with no serious adverse reactions. Some, mainly gastrointestinal complaints, registered in the first month (6%), were significantly relieved (p < 0.0001) after 12 months of treatment (1%). CONCLUSION: Ibandronate manifested significant improvement of the BMD after 12 months of treatment of patients with decreased BMD, with good tolerance and excellent treatment compliance.

The L266V tau mutation is associated with frontotemporal dementia and Pick-like 3R and 4R tauopathy.

We report a case of rapidly progressive frontotemporal dementia presenting at age 33 years. At autopsy there was severe atrophy of the frontal and temporal lobes. Tau-positive Pick bodies, which ultrastructurally were composed of straight filaments, were present, accompanied by severe neuronal loss and gliosis. RD3, a tau antibody specific for the three-repeat (3R) isoforms, labeled the Pick bodies. ET3, a four-repeat (4R) isoform-specific tau antibody, did not label Pick bodies, but highlighted rare astrocytes, and threads in white matter bundles in the corpus striatum. Analysis of the tau gene revealed an L266V mutation in exon 9. Analysis of brain tissue from this case revealed elevated levels of exon 10+ tau RNA and soluble 4R tau. However, both 3R and 4R isoforms were present in sarkosyl-insoluble tau fractions with a predominance of the shortest 3R isoform. The L266V mutation is associated with decreased rate and extent of tau-induced microtubule assembly, and a 3R isoform-specific increase in tau self assembly as measured by an in vitro assay. Combined, these data indicate that L266V is a pathogenic tau mutation that is associated with Pick-like pathology. In addition, the results of the RD3 and ET3 immunostains clearly explain for the first time the presence of both 3R and 4R tau isoforms in preparations of insoluble tau from some Pick's disease cases.