161 research outputs found
Sugar addiction: the state of the science.
PURPOSE: As obesity rates continue to climb, the notion that overconsumption reflects an underlying 'food addiction' (FA) has become increasingly influential. An increasingly popular theory is that sugar acts as an addictive agent, eliciting neurobiological changes similar to those seen in drug addiction. In this paper, we review the evidence in support of sugar addiction. METHODS: We reviewed the literature on food and sugar addiction and considered the evidence suggesting the addictiveness of highly processed foods, particularly those with high sugar content. We then examined the addictive potential of sugar by contrasting evidence from the animal and human neuroscience literature on drug and sugar addiction. RESULTS: We find little evidence to support sugar addiction in humans, and findings from the animal literature suggest that addiction-like behaviours, such as bingeing, occur only in the context of intermittent access to sugar. These behaviours likely arise from intermittent access to sweet tasting or highly palatable foods, not the neurochemical effects of sugar. CONCLUSION: Given the lack of evidence supporting it, we argue against a premature incorporation of sugar addiction into the scientific literature and public policy recommendations.Wellcome Trust (Senior Fellowship award)This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00394-016-1229-
Exploring participation after paediatric acquired brain injury
This study aimed to explore the levels of participation in a UK sample of children and young people (CYP) with an acquired brain injury (ABI) at home, school and in the community. The purpose of this study was to assess the feasibility of undertaking research with this population with a cross-sectional study using the Child and Family Follow-Up Survey (CFFS). The CFFS was distributed to parents/carers of 134 CYP with ABI (CYP-ABI) who received neuro-rehabilitation from 2014 to 2016. Access and recruitment was problematic resulting in a low response rate (4%). Widespread restrictions in participation were reported by 4 out of the 5 respondents with community structured events/activities and educational activities being the most restricted. Factors impacting on participation were cognitive-based and movement skills, family stress and lack of support/encouragement in the community. Study results provide information pertaining to the feasibility of undertaking research with this population whilst also highlighting the restrictions to participation experienced by CYP-ABI more than two years after injury. Abstract This study aimed to explore the levels of participation in a UK sample of children and youn
Correlation of Pool Boiling Curves for the Homologous Group: Freons
Nomenclature C L = specific heat of liquid g = gravitational acceleration h fg = latent heat of evaporation k L = thermal conductivity of liquid P c = thermodynamic critical pressure <7> <7max> tfmin = heat flux, maximum flux, minimum flux Introduction A knowledge of the complete boiling curve q versus AT for a liquid, including the regimes of nucleate boiling, transition boiling, and film boiling, and the peak and minimum crisis points is needed for the design and operation of various types of heat transfer equipment. No general method exists for predicting the complete curve. Most difficult is the prediction of the nucleate boiling curve, the transition curve, and the temperature that separates the two. If the curve for every liquid at every pressure must be determined experimentally, we are faced with a formidable task. This paper shows that some simplification is possible for members of a homologous group
Tropospheric Phase Calibration in Millimeter Interferometry
We review millimeter interferometric phase variations caused by variations in
the precipitable water vapor content of the troposphere, and we discuss
techniques proposed to correct for these variations. We present observations
with the Very Large Array at 22 GHz and 43 GHz designed to test these
techniques. We find that both the Fast Switching and Paired Array calibration
techniques are effective at reducing tropospheric phase noise for radio
interferometers. In both cases, the residual rms phase fluctuations after
correction are independent of baseline length for b > b_{eff}. These techniques
allow for diffraction limited imaging of faint sources on arbitrarily long
baselines at mm wavelengths. We consider the technique of tropospheric phase
correction using a measurement of the precipitable water vapor content of the
troposphere via a radiometric measurement of the brightness temperature of the
atmosphere. Required sensitivities range from 20 mK at 90 GHz to 1 K at 185 GHz
for the MMA, and 120 mK for the VLA at 22 GHz. The minimum gain stability
requirement is 200 at 185 GHz at the MMA assuming that the astronomical
receivers are used for radiometry. This increases to 2000 for an uncooled
system. The stability requirement is 450 for the cooled system at the VLA at 22
GHz. To perform absolute radiometric phase corrections also requires knowledge
of the tropospheric parameters and models to an accuracy of a few percent. It
may be possible to perform an `empirically calibrated' radiometric phase
correction, in which the relationship between fluctuations in brightness
temperature differences with fluctuations in interferometric phases is
calibrated by observing a celestial calibrator at regular intervals.Comment: AAS LATEX preprint format. to appear in Radio Science 199
A Causal Role of the Right Superior Temporal Sulcus in Emotion Recognition From Biological Motion
Understanding the emotions of others through nonverbal cues is critical for successful social interactions. The right posterior superior temporal sulcus (pSTS) is one brain region thought to be key in the recognition of the mental states of others based on body language and facial expression. In the present study, we temporarily disrupted functional activity of the right pSTS by using continuous, theta-burst transcranial magnetic stimulation (cTBS) to test the hypothesis that the right pSTS plays a causal role in emotion recognition from body movements. Participants (N = 23) received cTBS to the right pSTS, which was individually localized using fMRI, and a vertex control site. Before and after cTBS, we tested participantsâ ability to identify emotions from point-light displays (PLDs) of biological motion stimuli and a nonbiological global motion identification task. Results revealed that accurate identification of emotional states from biological motion was reduced following cTBS to the right pSTS, but accuracy was not impaired following vertex stimulation. Accuracy on the global motion task was unaffected by cTBS to either site. These results support the causal role of the right pSTS in decoding information about othersâ emotional state from their body movements and gestures
Analysis of Radiosonde and Ground-Based Remotely Sensed PWV Data from the 2004 North Slope of Alaska Arctic Winter Radiometric Experiment
Abstract
During 9 Marchâ9 April 2004, the North Slope of Alaska Arctic Winter Radiometric Experiment was conducted at the Atmospheric Radiation Measurement Program's (ARM) "Great White" field site near Barrow, Alaska. The major goals of the experiment were to compare microwave and millimeter wavelength radiometers and to develop forward models in radiative transfer, all with a focus on cold (temperature from 0° to â40°C) and dry [precipitable water vapor (PWV) < 0.5 cm] conditions. To supplement the remote sensors, several radiosonde packages were deployed: Vaisala RS90 launched at the ARM Duplex and at the Great White and Sippican VIZ-B2 operated by the NWS. In addition, eight dual-radiosonde launches were conducted at the Duplex with Vaisala RS90 and Sippican GPS Mark II, the latter one modified to include a chilled mirror humidity sensor. Temperature comparisons showed a nighttime bias between VIZ-B2 and RS90, which reached 3.5°C at 30 hPa. Relative humidity comparisons indicated better than 5% average agreement between the RS90 and the chilled mirror. A bias of about 20% for the upper troposphere was found in the VIZ-B2 and the Mark II measurements relative to both RS90 and the chilled mirror.
Comparisons in PWV were made between a microwave radiometer, a microwave profiler, a global positioning system receiver, and the radiosonde types. An RMS agreement of 0.033 cm was found between the radiometer and the profiler and better than 0.058 cm between the radiometers and GPS. RS90 showed a daytime dry bias on PWV of about 0.02 cm
Atmospheric Phase Correction Using Total Power Radiometry at the Submillimeter Array
Phase noise caused by an inhomogeneous, time-variable water vapor
distribution in our atmosphere reduces the angular resolution, visibility
amplitude and coherence time of millimeter and submillimeter wavelength
interferometers. We present early results from our total power radiometry phase
correction experiment carried out with the Submillimeter Array on Mauna Kea.
From accurate measurements of the atmospheric emission along the lines of
sight of two elements of the array, we estimated the differential atmospheric
electrical path between them. In one test, presented here, the phase correction
technique reduced the rms phase noise at 230 GHz from 72\degr to 27\degr
over a 20 minute period with a 2.5 second integration time. This corresponds to
a residual differential electrical path of 98 m, or 15 m of
precipitable water vapor, and raises the coherence in the 20 minute period from
0.45 to 0.9.Comment: Accepted for publication in the SMA Special Volume of the ApJ Letters
(9 pages of text, 3 figures
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Combined effects of age and BMI are related to altered cortical thickness in adolescence and adulthood.
Overweight and obesity are associated with functional and structural alterations in the brain, but how these associations change across critical developmental periods remains unknown. Here, we examined the relationship between age, body mass index (BMI) and cortical thickness (CT) in healthy adolescents (nâŻ=âŻ70; 14-19 y) and adults (nâŻ=âŻ75; 25-45 y). We also examined the relationship between adiposity, impulsivity, measured by delay discounting (DD), and CT of the inferior frontal gyrus (IFG), a region key to impulse control. A significant age-by-BMI interaction was observed in both adolescents and adults; however, the direction of this relationship differed between age groups. In adolescents, increased age-adjusted BMI Z-score attenuated age-related CT reductions globally and in frontal, temporal and occipital regions. In adults, increased BMI augmented age-related CT reductions, both globally and in bilateral parietal cortex. Although DD was unrelated to adiposity in both groups, increased DD and adiposity were both associated with reduced IFG thickness in adolescents and adults. Our findings suggest that the known age effects on CT in adolescence and adulthood are moderated by adiposity. The association between weight, cortical development and its functional implications would suggest that future studies of adolescent and adult brain development take adiposity into account
Critical Exponents, Hyperscaling and Universal Amplitude Ratios for Two- and Three-Dimensional Self-Avoiding Walks
We make a high-precision Monte Carlo study of two- and three-dimensional
self-avoiding walks (SAWs) of length up to 80000 steps, using the pivot
algorithm and the Karp-Luby algorithm. We study the critical exponents
and as well as several universal amplitude ratios; in
particular, we make an extremely sensitive test of the hyperscaling relation
. In two dimensions, we confirm the predicted
exponent and the hyperscaling relation; we estimate the universal
ratios , and (68\% confidence
limits). In three dimensions, we estimate with a
correction-to-scaling exponent (subjective 68\%
confidence limits). This value for agrees excellently with the
field-theoretic renormalization-group prediction, but there is some discrepancy
for . Earlier Monte Carlo estimates of , which were , are now seen to be biased by corrections to scaling. We estimate the
universal ratios and ; since , hyperscaling holds. The approach to
is from above, contrary to the prediction of the two-parameter
renormalization-group theory. We critically reexamine this theory, and explain
where the error lies.Comment: 87 pages including 12 figures, 1029558 bytes Postscript
(NYU-TH-94/09/01
Facile Pyrolytic Synthesis of Silicon Nanowires
One-dimensional nanostructures such as silicon nanowires (SiNW) are attractive candidates for low power density electronic and optoelectronic devices including sensors. A new simple method for SiNW bulk synthesis[1, 2] is demonstrated in this work, which is inexpensive and uses low toxicity materials, thereby offering a safe, energy efficient and green approach. The method uses low flammability liquid phenylsilanes, offering a safer avenue for SiNW growth compared with using silane gas. A novel, duo-chamber glass vessel is used to create a low-pressure environment where SiNWs are grown through vapor-liquid-solid mechanism using gold nanoparticles as a catalyst. The catalyst decomposes silicon precursor vapors of diphenylsilane and triphenylsilane and precipitates single crystal SiNWs, which appear to grow parallel to the substrate surface. This opens up possibilities for synthesizing nano-junctions amongst wires which is important for the grid architecture of nanoelectronics proposed by Likharev[3]. Even bulk synthesis of SiNW is feasible using sacrificial substrates such as CaCO(3) that can be dissolved post-synthesis. Furthermore, by dissolving appropriate dopants in liquid diphenylsilane, a controlled doping of the nanowires is realized without the use of toxic gases and expensive mass flow controllers. Upon boron doping, we observe a characteristic red shift in photoluminescence spectra. In summary, an inexpensive and versatile method for SiNW is presented that makes these exotic materials available to any lab at low cost
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