367 research outputs found
Reciprocal inhibition in co-contracting forearm muscles during suppression of motor cortical output: evidence suggesting that the central command for decreased reciprocal inhibition is uncoupled from motor cortical activity
No full textImpact of backgrounds and light scenes' characteristics on paintings' perception
No full textIn recent years LED light sources' characteristics rapidly improved while their costs
decreased, making their use more and more widespread. In more detail, LEDs' colour
rendering index (CRI) was constantly upgraded; such parameter is important to guarantee a
good colour perception in indoor environments in order to ensure users' comfort and
wellbeing. People's colour perception is also affected by environmental conditions, such as
surfaces' optical characteristics, light sources' spectral power distribution (SPD) and
illuminance levels. This topic is particularly relevant in museums, the main goal of which is to
enhance artworks' perception by choosing the proper lighting system and setting's
characteristics. To investigate how people perceive an artwork when changing light scenes'
and setting's characteristics, a test on 21 subjects was carried out and the results are
reported in this paper
Electrical stimulation over muscle tendons in humans - Evidence favouring presynaptic inhibition of Ia fibres due to the activation of group III tendon afferents
No full textElectrical stimulation over muscle tendons produces a transient suppression of voluntary EMG activity; its onset latency is similar to 55 ms in the forearm extensor muscles. This phenomenon has been attributed to the activation of a polysynaptic inhibitory pathway originating from II, afferent fibres. To clarify its origin we conducted several experiments in IO nor-mal healthy subjects. The EMG silence after tendon stimulation appeared at relatively high stimulus intensities (>50 mA); conditioning cutaneous stimulation left it unchanged, and the inhibition had a short recovery cycle (50 ms). Tendon stimulation still evoked EMG suppression during an ischaemic block of fast-conducting afferents. The motor potentials evoked bq, transcranial magnetic stimulation of the motor cortex during the EMG silence remained almost unchanged, whereas the H reflex was strongly inhibited Hence we conclude that tendon stimulation activates slow-conducting tendon afferents, possibly group III fibres, connected not through a polysynaptic pathway originating from Ib afferents but through nit oligo-or disynaptic inhibitory circuit. The EMG suppression after tendon stimulation probably represents a dysfacilitation of the alpha-motor neurons due to presynaptic inhibition of In fibres produced by tendon afferent input to the spinal cord
Immigration, Labor Market Mobility, and the Earnings of Native-born Workers: An Occupational Segmentation Approach
No full textThis paper seeks to improve on previous estimates of the impact of immigration on native wages by using an occupational segmentation approach that directly controls for regional migration and other shifts in native-born labor supply. The labor market is segmented by occupation in order to determine which, if any, native workers tend to be vulnerable to increased immigrant competition for jobs. The results suggest that nativeborn workers in the primary sector are the main beneficiaries of increased immigration, while native-born Hispanic females in the secondary sector are the most susceptible to downward wage pressures.
Effects Of Variation Of The Color Characteristics Of Lighting Sources By The Environmental Context
No full textOver recent years the importance of using daylight in indoor environments to achieve reductions of energy consumption was largely discussed, but the use of
daylight is even more important because of its effects on human beings.
Daylight has a more uniform spectral distribution than the artificial sources (especially discharge lamps) and consequently it allows a better color perception;
moreover it changes during the day both in intensity and spectral power distribution (SPD).
For all these reasons, daylight ensures a high comfort in carrying out all the human activities and is also important to the circadian rhythm regulation; therefore it results necessary to evaluate the entrance of natural light in indoor environments both in qualitative and quantitative terms.
Until now, the approach was mainly based on the daylight factor (DF) value, while the spectral composition of radiations coming from the sky was not considered. A
proper use of daylight in indoor environments requires integration with electric lighting. Nowadays a designer can choose light sources with the most appropriate
color tone, expressed by means of correlated color temperature (CCT); for indoor applications, the most popular are mainly fluorescent and LED sources, each
disposable with different CCT. However, lit environments can be perceived differently under sources with the same CCT but different SPDs.
In this paper, an analysis of the characteristics of daylight and electric lighting in an indoor environment is carried out, by comparing SPDs and CCTs of the natural
source (sky) during typical winter days with contemporaneous measurements of spectral irradiances and CCTs detected at the eyes level.
From results obtained, the influence of indoor environment over spectral distribution of radiations, both from daylight and electric light, was evaluated
Electrical stimulation over muscle tendons in humans: evidence favouring presynaptic inhibition of Ia fibres due to the activation of group III tendon afferents
No full textOne-hour postload hyperglycemia confers higher risk of hepatic steatosis to HbA1c-defined prediabetic subjects
No full textCONTEXT:
Individuals with glycated hemoglobin (HbA1c)-defined prediabetes (HbA1c value of 5.7-6.4%) and 1-hour plasma glucose ≥155 mg/dL during an oral glucose tolerance test have an increased risk of developing type 2 diabetes.
OBJECTIVE:
To evaluate the degree to which HbA1c-defined prediabetes and 1-hour postload glucose ≥155 mg/dL individually and jointly associate with hepatic steatosis and related biomarkers.
DESIGN AND PATIENTS:
A cross-sectional analysis was performed on 1108 White individuals.
SETTING:
Ambulatory care.
MAIN OUTCOME MEASURES:
Anthropometric and metabolic characteristics including hepatic steatosis assessed by ultrasonography.
RESULTS:
Compared with the normal group (HbA1c <5.7%), HbA1c-defined prediabetic and diabetic individuals exhibit higher values of fasting, 1-hour, and 2-hour postload glucose; fasting and 2-hour postload insulin; triglycerides; uric acid; homeostasis model of assessment for insulin resistance; liver insulin resistance index; liver enzymes; and inflammatory biomarkers; and lower levels of high-density lipoprotein cholesterol and IGF-1. Prediabetic and diabetic subjects have increased risk of hepatic steatosis (1.5- and 2.46-fold, respectively). Stratifying participants according to HbA1c and 1-hour postload glucose, we found that individuals with HbA1c-defined prediabetes and 1-hour postload glucose ≥155 mg/dL have significantly higher risk of hepatic steatosis as compared with individuals with HbA1c-defined prediabetes but 1-hour postload glucose <155 mg/dL. Individuals with HbA1c-defined prediabetes and 1-hour postload glucose ≥155 mg/dL exhibit higher values of liver enzymes; fasting, 1-hour, and 2-hour postload glucose; insulin; triglycerides; uric acid; and inflammatory biomarkers; and lower levels of high-density lipoprotein and IGF-1.
CONCLUSIONS:
These data suggest that a value of 1-hour postload glucose ≥155 mg/dL may be helpful to identify a subset of individuals within HbA1c-defined glycemic categories at higher risk of hepatic steatosis
A nove heterozygous SOX2 mutation causing anophtalmia/microphtalmia with genital anomalies
No full textAnophthalmia/microphthalmia is a rare developmental craniofacial defect, which recognizes a wide range of causes, including chromosomal abnormalities, single-gene mutations as well as environmental factors. Heterozygous mutations in the SOX2 gene are the most common monogenic form of anophthalmia/microphthalmia, as they are reported in up to 10-15% cases. Here, we describe a sporadic patient showing bilateral anophthalmia/microphthalmia and micropenis caused by a novel mutation (c.59_60insGG) in the SOX2 gene. Morphological and endocrinological evaluations excluded any anomaly of the hypothalamus-pituitary axis. Our finding supports the hypothesis that SOX2 is particularly prone to slipped-strand mispairing, which results in a high frequency of point deletions/insertions
Problemas de física : curso de ingreso
No full textFil:Luna, Osvaldo L.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Arias, César F.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Aróstegui, Oscar A.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Cretella, Rúben F.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Fernández, José L.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil: Gómez, Félix M.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Guaragna, Mario K.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Lombardo, Carlos E.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil: Pedace, Eduardo E.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil: Perrot, Alberto M.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Trozo, Osvaldo A.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, ArgentinaFil:Verzura, Guillermo O.. Universidad de Buenos Aires. Facultad de Ingeniería. Buenos Aires, Argentin
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