A versatile microfadometer for lightfastness testing and pigment identification

The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x107 lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ΔEab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ΔEab over 1 hour and 0.31 ΔEab over 7 hours. A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented

Photochemical colour change for traditional watercolour pigments in low oxygen levels

An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 − 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support

The homotopy theory of simplicial props

The category of (colored) props is an enhancement of the category of colored operads, and thus of the category of small categories. In this paper, the second in a series on "higher props," we show that the category of all small colored simplicial props admits a cofibrantly generated model category structure. With this model structure, the forgetful functor from props to operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat

Quasi-simultaneous observations of the BL Lac object MK 501 in X-ray, UV, visible, IR and radio frequencies

Quasi-simultaneous observations of the BL Lacertae (Lac) objects MK 501 were performed for the first time at X-ray, ultraviolet, visible, infrared, and radio frequencies. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical radio emission can not be accounted for by a single power law. Several theoretical models were considered for the emission mechanism. A quantitative comparison was performed with the synchrotron-self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object is underestimated by a factor of about three or four

Universal and unique features of kinesin motors: Insights from a comparison of fungal and animal conventional kinesins

Kinesins are microtubule motors that use the energy derived from the hydrolysis of ATP to move unidirectionally along microtubules, The founding member of this still growing superfamily is conventional kinesin, a dimeric motor that moves processively towards the plus end of microtubules, Within the family of conventional kinesins, two groups can be distinguished to date, one derived from animal species, and one originating from filamentous fungi. So far no conventional kinesin has been reported from plant cells. Fungal and animal conventional kinesins differ in several respects, both in terms of their primary sequence and their physiological properties. Thus all fungal conventional kinesins move at velocities that are 4-5 times higher than those of animal conventional kinesins, and all of them appear to lack associated light chains. Both groups of motors are characterized by a number of group-specific sequence features which are considered here with respect to their functional importance. Animal and fungal conventional kinesins also share a number of sequence characteristics which point to common principles of motor function. The overall domain organization is remarkably similar. A C-terminal sequence motif common to all kinesins, which constitutes the only region of high homology outside the motor domain, suggests common principles of cargo association in both groups of motors. Consideration of the differences of, and similarities between, fungal and animal kinesins offers novel possibilities for experimentation (e.g., by constructing chimeras) that can be expected to contribute to our understanding of motor function

Dynamic concentration of motors in microtubule arrays

We present experimental and theoretical studies of the dynamics of molecular motors in microtubule arrays and asters. By solving a convection-diffusion equation we find that the density profile of motors in a two-dimensional aster is characterized by continuously varying exponents. Simulations are used to verify the assumptions of the continuum model. We observe the concentration profiles of kinesin moving in quasi two-dimensional artificial asters by fluorescent microscopy and compare with our theoretical results.Comment: 4pages, 4 figures revte

Nutrition Coupled with High-Load Traditional or Low-Load Blood Flow Restricted Exercise During Human Limb Suspension

High-load resistance exercise (HRE) and low-load blood flow restricted (BFR) exercise have demonstrated efficacy for attenuating unloading related muscle atrophy and dysfunction. In recreational exercisers, protein consumption immediately before and/or after exercise has been shown to increase the skeletal muscle anabolic response to resistance training. PURPOSE: To compare the skeletal muscle adaptations when chocolate milk intake was coupled with HRE or low-load BFR exercise [3 d/wk] during simulated lower limb weightlessness. METHODS: Eleven subjects were counterbalanced [based on age and gender] to HRE (31 +/- 14 yr, 170 +/- 13 cm, 71 +/- 18 kg, 2M/3W) or low-load BFR exercise (31 +/- 12 yr, 169 +/- 13 cm, 66 +/- 14 kg, 2M/4W) during 30 days of unilateral lower limb suspension (ULLS). Both HRE and BFR completed 3 sets of single leg press and calf raise exercise during ULLS. BFR exercise intensity was 20% of repetition maximum (1RM) with a cuff inflation pressure of 1.3 systolic blood pressure (143 4 mmHg). Cuff pressure was maintained during all 3 sets including rest intervals (90s). HRE intensity was 75% 1RM and was performed without cuff inflation. Immediately (<10 min) before and after exercise 8 fl oz of chocolate milk (150 kcal, 2.5g total fat, 22g total carbohydrate, 8g protein) was consumed to optimize acute exercise responses in favor of muscle anabolism. ULLS analog compliance was assessed from leg skin temperature recordings and plantar accelerometry. Muscle cross-sectional area (CSA) for knee extensor and plantar flexor muscle groups were determined from analysis of magnetic resonance images using ImageJ software. 1RM strength for leg press and calf raise was assessed on the Agaton exercise system. Muscular endurance during leg press and calf raise was evaluated from the maximal number of repetitions performed to volitional fatigue using 40% of pre-ULLS 1RM. RESULTS: Steps detected by plantar acceleometry declined by 98.9% during ULLS relative to an ambulatory control period. Average skin temperature of the unloaded calf declined from 27.4 C to 26.8 C (-2.1%), while there was a slight increase (+1.1%) in skin temperature in the loaded calf (27.6 C to 27.9 C). Collectively, these measures indicate strong subject compliance with the ULLS analog. Unloaded limb work performed during leg press (1514 +/- 334 vs. 576 +/- 103) and calf raise (2886 +/- 508 vs. 1233 +/- 153) exercises sessions was greater in HRE vs. BFR, respectively. Leg press training loads were 44 +/- 7 kg in HRE compared to 11 +/- 1 kg in BFR. Similarly, calf raise training loads were 81 +/- 11 kg in HRE and 16 +/- 1 kg in BFR. Pre to post-ULLS training adaptations in the unloaded leg are shown in the table. CONCLUSION: The preliminary results of this investigation suggest when HRE is optimized for muscle anabolism during unloading muscle size and strength are preserved (or enhanced) at the expense of muscle endurance. In contrast, when BFR exercise is optimized for muscle anabolism during unloading muscle endurance is preserved (or enhanced) at the expense of muscle size and strengt

The Nature and Purpose of Acute Psychiatric Wards: The Tompkins Acute Ward Study

Background: Acute inpatient care in the UK is being subjected to increasing critical scrutiny, highlighting concerns about content and quality. There is an absence of clarity and consensus on what acute inpatient care is for, adding to difficulties in developing this service sector. Aim: To define the function of acute psychiatric wards. Methods: Interviews were conducted with multidisciplinary staff (13 Ward Managers, 14 F Grade nurses, 11 Occupational Therapists and 9 Consultant Psychiatrists), on rationales for admission, their care and treatment philosophy, and the roles of different professionals. Results: Patients are admitted because they appear likely to harm themselves or others, and because they are suffering from a severe mental illness, and/or because they or their family/community require respite, and/or because they have insufficient support and supervision available to them in the community. The tasks of acute inpatient care are to keep patients safe, assess their problems, treat their mental illness, meet their basic care needs and provide physical healthcare. These tasks are completed via containment, 24-hour staff presence, treatment provision, and complex organisation and management. Conclusions: Professional education, audit, research and the structuring of services all need to be oriented towards these tasks. Declaration of interest: This study was funded by the Tompkins Foundation and the Department of Health Nursing Quality initiative

Perceptions of childhood immunization in a minority community: Qualitative study

This is the author's accepted manuscript. The final published article is available from the link below. Published article copyright @ The Royal Society of Medicine.Objective - To assess reasons for low uptake of immunization amongst orthodox Jewish families. Design - Qualitative interviews with 25 orthodox Jewish mothers and 10 local health care workers. Setting - The orthodox Jewish community in North East London. Main outcome measures - Identification of views on immunization in the orthodox Jewish community. Results - In a community assumed to be relatively insulated from direct media influence, word of mouth is nevertheless a potent source of rumours about vaccination dangers. The origins of these may lie in media scares that contribute to anxieties about MMR. At the same time, close community cohesion leads to a sense of relative safety in relation to tuberculosis, with consequent low rates of BCG uptake. Thus low uptake of different immunizations arises from enhanced feelings of both safety and danger. Low uptake was not found to be due to the practical difficulties associated with large families, or to perceived insensitive cultural practices of health care providers. Conclusions - The views and practices of members of this community are not homogeneous and may change over time. It is important that assumptions concerning the role of religious beliefs do not act as an obstacle for providing clear messages concerning immunization, and community norms may be challenged by explicitly using its social networks to communicate more positive messages about immunization. The study provides a useful example of how social networks may reinforce or challenge misinformation about health and risk and the complex nature of decision making about children's health.City and Hackney Teaching Primary Care Trus

Modulation of outer bank erosion by slump blocks: Disentangling the protective and destructive role of failed material on the three-dimensional flow structure

The three-dimensional flow field near the banks of alluvial channels is the primary factor controlling rates of bank erosion. Although submerged slump blocks and associated large-scale bank roughness elements have both previously been proposed to divert flow away from the bank, direct observations of the interaction between eroded bank material and the 3-D flow field are lacking. Here we use observations from multibeam echo sounding, terrestrial laser scanning, and acoustic Doppler current profiling to quantify, for the first time, the influence of submerged slump blocks on the near-bank flow field. In contrast to previous research emphasizing their influence on flow diversion away from the bank, we show that slump blocks may also deflect flow onto the bank, thereby increasing local shear stresses and rates of erosion. We use our measurements to propose a conceptual model for how submerged slump blocks interact with the flow field to modulate bank erosion.UK Natural Environment Research Council (NERC