Distance doubling visual acuity test: a reliable test for nonorganic visual loss

BACKGROUND: To determine the value of the distance doubling visual acuity test in the diagnosis of nonorganic visual loss in a comparative observational case series. METHODS: Twenty-one consecutive patients with nonorganic visual acuity loss and 21 subjects with organic visual loss as controls were included. Best corrected visual acuity was tested at the normal distance of 5 meters using Landolt Cs. The patient was then repositioned and best corrected visual acuity was tested with the previous optotypes at double the distance via a mirror. RESULTS: Nonorganic visual acuity loss was identified in 21 of 21 patients. Sensitivity and specificity of distance-doubling visual acuity test in functional visual loss were found to be 100% (CI; 83%-100%) and 100% (CI; 82%-100%), respectively. CONCLUSION: Distance doubling visual acuity test is widely used to detect nonorganic visual loss. Our results show that this test has a high specificity and sensitivity to detect nonorganic visual impairment.

Prostate specific antigen doubling time as auxiliary end point in hormone refractory prostatic carcinoma

In hormone refractory prostatic carcinoma (HRPCa), the majority of patients have bone metastases only, which are by definition non-measurable. This makes objective evaluation of chemotherapeutic agents difficult. Prostate specific antigen (PSA) as a dynamic model was analyzed as potential auxiliary end point in HRPCa.

Microstates in language-related brain potential maps show noun-verb differences

Brain processing of grammatical word class was studied analyzing event-related potential (ERP) brain fields. Normal subjects observed a randomized sequence of single German nouns and verbs on a computer screen, while 20-channel ERP field map series were recorded separately for both word classes. Spatial microstate analysis was applied, based on the observation that series of ERP maps consist of epochs of quasi-stable map landscapes and based on the rationale that different map landscapes must have been generated by different neural generators and thus suggest different brain functions. Space-oriented segmentation of the mean map series identified nine successive, different functional microstates, i.e., steps of brain information processing characterized by quasi-stable map landscapes. In the microstate from 116 to 172 msec, noun-related maps differed significantly from verb-related maps along the left–right axis. The results indicate that different neural populations represent different grammatical word classes in language processing, in agreement with clinical observations. This word class differentiation as revealed by the spatial–temporal organization of neural activity occurred at a time after word input compatible with speed of reading.

Biactantial agreement in the Gongduk transitive verb in the broader Tibeto-Burman context

The Gongduk language is spoken in an enclave in south central Bhutan comprising several villages and hamlets in the mountains west of the Kurichu. The language occupies a distinct phylogenetic position within the Tibeto-Burman language family. The intransitive verb agrees for person and number with the subject, and the transitive shows biactantial agreement for person and number with both agent and patient. A morphological analysis has identified the individual agreement morphemes, their precise grammatical meaning and their patterns of allomorphy. The cognacy of the greater part of the desinences of the Gongduk verb with morphemes identifiable in the biactantial agreement systems of other Tibeto-Burman languages supports the view that at least a portion of such conjugational morphology must be reconstructed to the common ancestral language.

Yellow laser light generation by frequency doubling of the output from a master oscillator fiber power amplifier system

We present a power-scalable approach for yellow laser-light generation based on standard Ytterbium (Yb) doped fibers. To force the cavity to lase at 1154 nm, far above the gain-maximum, measures must be taken to fulfill lasing condition and to suppress competing amplified spontaneous emission (ASE) in the high-gain region. To prove the principle we built a fiber-laser cavity and a fiber-amplifier both at 1154 nm. In between cavity and amplifier we suppressed the ASE by 70 dB using a fiber Bragg grating (FBG) based filter. Finally we demonstrated efficient single pass frequency doubling to 577 nm with a periodically poled lithium niobate crystal (PPLN). With our linearly polarized 1154 nm master oscillator power fiber amplifier (MOFA) system we achieved slope efficiencies of more than 15 % inside the cavity and 24 % with the fiber-amplifier. The frequency doubling followed the predicted optimal efficiency achievable with a PPLN crystal. So far we generated 1.5 W at 1154nm and 90 mW at 577 nm. Our MOFA approach for generation of 1154 nm laser radiation is power-scalable by using multi-stage amplifiers and large mode-area fibers and is therefore very promising for building a high power yellow laser-light source of several tens of Watt.

Decomposing hierarchical alignment: Co-arguments as conditions on alignment and the limits of referential hierarchies as explanations in verb agreement

Apart from common cases of differential argument marking, referential hierarchies affect argument marking in two ways: (a) through hierarchical marking, where markers compete for a slot and the competition is resolved by a hierarchy, and (b) through co-argument sensitivity, where the marking of one argument depends on the properties of its co-argument. Here we show that while co-argument sensitivity cannot be analyzed in terms of hierarchical marking, hierarchical marking can be analyzed in terms of co-argument sensitivity. Once hierarchical effects on marking are analyzed in terms of co-argument sensitivity, it becomes possible to examine alignment patterns relative to referential categories in exactly the same way as one can examine alignment patterns relative to referential categories in cases of differential argument marking and indeed any other condition on alignment (such as tense or clause type). As a result, instances of hierarchical marking of any kind turn out not to present a special case in the typology of alignment, and there is no need for positing an additional non-basic alignment type such as “hierarchical alignment”. While hierarchies are not needed for descriptive and comparative purposes, we also cast doubt on their relevance in diachrony: examining two families for which hierarchical agreement has been postulated, Algonquian and Kiranti, we find only weak and very limited statistical evidence for agreement paradigms to have been shaped by a principled ranking of person categories.

Fine particulate matter measurements in Swiss restaurants, cafés and bars: what is the effect of spatial separation between smoking and non-smoking areas?

We performed 124 measurements of particulate matter (PM(2.5)) in 95 hospitality venues such as restaurants, bars, cafés, and a disco, which had differing smoking regulations. We evaluated the impact of spatial separation between smoking and non-smoking areas on mean PM(2.5) concentration, taking relevant characteristics of the venue, such as the type of ventilation or the presence of additional PM(2.5) sources, into account. We differentiated five smoking environments: (i) completely smoke-free location, (ii) non-smoking room spatially separated from a smoking room, (iii) non-smoking area with a smoking area located in the same room, (iv) smoking area with a non-smoking area located in the same room, and (v) smoking location which could be either a room where smoking was allowed that was spatially separated from non-smoking room or a hospitality venue without smoking restriction. In these five groups, the geometric mean PM(2.5) levels were (i) 20.4, (ii) 43.9, (iii) 71.9, (iv) 110.4, and (v) 110.3 microg/m(3), respectively. This study showed that even if non-smoking and smoking areas were spatially separated into two rooms, geometric mean PM(2.5) levels in non-smoking rooms were considerably higher than in completely smoke-free hospitality venues. PRACTICAL IMPLICATIONS: PM(2.5) levels are considerably increased in the non-smoking area if smoking is allowed anywhere in the same location. Even locating the smoking area in another room resulted in a more than doubling of the PM(2.5) levels in the non-smoking room compared with venues where smoking was not allowed at all. In practice, spatial separation of rooms where smoking is allowed does not prevent exposure to environmental tobacco smoke in nearby non-smoking areas.

Properties of low-threshold motor axons in the human median nerve

This study investigated the excitability and accommodative properties of low-threshold human motor axons to test whether these motor axons have greater expression of the persistent Na(+) conductance, I(NaP). Computer-controlled threshold tracking was used to study 22 single motor units and the data were compared with compound motor potentials of various amplitudes recorded in the same experimental session. Detailed comparisons were made between the single units and compound potentials that were 40% or 5% of maximal amplitude, the former because this is the compound potential size used in most threshold tracking studies of axonal excitability, the latter because this is the compound potential most likely to be composed entirely of motor axons with low thresholds to electrical recruitment. Measurements were made of the strength-duration relationship, threshold electrotonus, current-voltage relationship, recovery cycle and latent addition. The findings did not support a difference in I(NaP). Instead they pointed to greater activity of the hyperpolarization-activated inwardly rectifying current (I(h)) as the basis for low threshold to electrical recruitment in human motor axons. Computer modelling confirmed this finding, with a doubling of the hyperpolarization-activated conductance proving the best single parameter adjustment to fit the experimental data. We suggest that the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel(s) expressed on human motor axons may be active at rest and contribute to resting membrane potential.