Density and T1T_1 of surface and bulk spins in diamond in high magnetic field gradients

We report on surface and bulk spin density measurements of diamond, using ultra-sensitive magnetic force microscopy with magnetic field gradients up to 0.5 T/$\mu$m. At temperatures between 25 and 800 mK, we measure the shifts in the resonance frequency and quality factor of a cantilever with a micromagnet attached to it. A recently developed theoretical analysis allows us to extract a surface spin density of 0.072 spins/nm$^2$ and a bulk spin density of 0.4 ppm from this data. In addition, we find an increase of the $T_1$ time of the surface spins in high magnetic field gradients due to the suppression of spin diffusion. Our technique is applicable to a variety of samples other than diamond, and could be of interest for several research fields where surface, interface or impurity bulk spin densities are an important factor.Comment: 7 pages, 6 figure

Sponges of the family Esperiopsidae (Demospongiae, Poecilosclerida) from Northwest Africa, with the descriptions of four new species

Sponges belonging to the genera Amphilectus Vosmaer, Esperiopsis Carter and Ulosa de Laubenfels of the family Esperiopsidae were collected during 1986 and 1988 expeditions of the Netherlands Centre for Biodiversity Naturalis (at that time the National Museum of Natural History at Leiden and the Zoological Museum of Amsterdam) in waters off the coasts of Mauritania and the Cape Verde Islands. Four new species, Amphilectus utriculus sp. nov., Amphilectus strepsichelifer sp. nov., Esperiopsis cimensis sp. nov., Ulosa capblancensis sp. nov., and two already known species, Amphilectus cf. fucorum (Esper) and Ulosa stuposa (Esper) are described and discussed

Incidence and risk factors of open-angle glaucoma : the Rotterdam study

__Abstract__ Glaucoma is one of the poorest understood and defined eye diseases among those known since our era. Despite two millennia of writing about glaucoma, a straightforward and clear-cut definition is not available worldwide. In essence, glaucoma is an eye disease characterized by loss of retinal ganglion cells and their axons. Clinically, this loss becomes apparent by cupping, also called excavation, of the optic disc and concomitant visual field loss. There are many subgroups of glaucoma, separated by causes, genetics, or morphology, and within each group there may be tens of different glaucoma types. From the start, I would like to point out that this thesis focuses on primary open-angle glaucoma. This is glaucoma in which the persons have open angles in their anterior eye chamber, through which the intraocular fluid leaves the eye. Moreover, all causes of secondary glaucoma, such as inflammation, medication, and systemic disorders, should have been eliminated with a reasonable amount of certainty. Since open-angle glaucoma cases with pseudoexfoliation were not specifically excluded at baseline of the Rotterdam study, we prefer to refer to open-angle glaucoma instead of primary open-angle glaucoma although during follow-up, no pseudoexfoliation was observed

Are we witnessing the decline effect in the Type D personality literature? What can be learned?

After an unbroken series of positive, but underpowered studies seemed to demonstrate Type D personality predicting mortality in cardiovascular disease patients, initial claims now appear at least exaggerated and probably false. Larger studies with consistently null findings are accumulating. Conceptual, methodological, and statistical issues can be raised concerning the construction of Type D personality as a categorical variable, whether Type D is sufficiently distinct from other negative affect variables, and if it could be plausibly assumed to predict mortality independent of depressive symptoms and known biomedical factors, including disease severity. The existing literature concerning negative affect and health suggests a low likelihood of discovering a new negative affect variable that independently predicts mortality better than its many rivals. The apparent decline effect in the Type D literature is discussed in terms of the need to reduce the persistence of false positive findings in the psychosomatic medicine literature, even while preserving a context allowing risk-taking and discovery. Recommendations include greater transparency concerning research design and analytic strategy; insistence on replication with larger samples before accepting "discoveries" from small samples; reduced confirmatory bias; and availability of all relevant data. Such changes would take time to implement, face practical difficulties, and run counter to established practices. An interim solution is for readers to maintain a sense of pre-discovery probabilities, to be sensitized to the pervasiveness of the decline effect, and to be skeptical of claims based on findings reaching significance in small-scale studies that have not been independently replicated. (C) 2012 Elsevier Inc. All rights reserved