1,287 research outputs found
Cavitating leukoencephalopathy in a child carrying the mitochondrial A8344G mutation.
Mitochondrial disorders are usually characterized by the combination of deep gray and white matter involvement on brain imaging. However, a selective white matter involvement has been reported in specific mitochondrial diseases, including Leber hereditary optic neuropathy, myoneurogastrointestina
Relationship between External and Internal Workloads in Elite Soccer Players : Comparison between Rate of Perceived Exertion and Training Load
The use of machine learning (ML) in soccer allows for the management of a large amount of data deriving from the monitoring of sessions and matches. Although the rate of perceived exertion (RPE), training load (S-RPE), and global position system (GPS) are standard methodologies used in team sports to assess the internal and external workload; how the external workload affects RPE and S-RPE remains still unclear. This study explores the relationship between both RPE and SRPE and the training workload through ML. Data were recorded from 22 elite soccer players, in 160 training sessions and 35 matches during the 2015/2016 season, by using GPS tracking technology. A feature selection process was applied to understand which workload features influence RPE and SRPE the most. Our results show that the training workloads performed in the previous week have a strong effect on perceived exertion and training load. On the other hand, the analysis of our predictions shows higher accuracy for medium RPE and S-RPE values compared with the extremes. These results provide further evidence of the usefulness of ML as a support to athletic trainers and coaches in understanding the relationship between training load and individual-response in team sports
Surface reactivity of tributyl thiophosphate: effects of temperature and mechanical stress
The surface reactivity of tributyl thiophosphate on iron surfaces has been studied in situ by attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reaction and desorption spectroscopies. The results show that at temperatures lower than 373K the molecule forms a physisorbed layer on the iron substrate. At 373K a reaction takes place with the formation of an organic layer, together with iron polyphosphate and sulfate. At higher temperatures temperature-programmed desorption results suggest that the mechanism involves P-O bond scission to yield butoxy groups. This could be preceded by P=S bond scission to give tributyl phosphite, which then, in turn, undergoes P-O bond scission to produce butoxy groups. The results obtained following tribological testing are in agreement with those of thermal tests: evidence of polyphosphate and sulfate formation is foun
Design and fabrication of densely integrated silicon quantum dots using a VLSI compatible hydrogen silsesquioxane electron beam lithography process
Hydrogen silsesquioxane (HSQ) is a high resolution negative-tone electron beam resist allowing for direct transfer of nanostructures into silicon-on-insulator. Using this resist for electron beam lithography, we fabricate high density lithographically defined Silicon double quantum dot (QD) transistors. We show that our approach is compatible with very large scale integration, allowing for parallel fabrication of up to 144 scalable devices. HSQ process optimisation allowed for realisation of reproducible QD dimensions of 50 nm and tunnel junction down to 25 nm. We observed that 80% of the fabricated devices had dimensional variations of less than 5 nm. These are the smallest high density double QD transistors achieved to date. Single electron simulations combined with preliminary electrical characterisations justify the reliability of our device and process
Experimental results of crystal-assisted slow extraction at the SPS
The possibility of extracting highly energetic particles from the Super
Proton Synchrotron (SPS) by means of silicon bent crystals has been explored
since the 1990's. The channelling effect of a bent crystal can be used to
strongly deflect primary protons and eject them from the synchrotron. Many
studies and experiments have been carried out to investigate crystal
channelling effects. The extraction of 120 and 270 GeV proton beams has already
been demonstrated in the SPS with dedicated experiments located in the ring.
Presently in the SPS, the UA9 experiment is performing studies to evaluate the
possibility to use bent silicon crystals to steer particle beams in high energy
accelerators. Recent studies on the feasibility of extraction from the SPS have
been made using the UA9 infrastructure with a longer-term view of using
crystals to help mitigate slow extraction induced activation of the SPS. In
this paper, the possibility to eject particles into the extraction channel in
LSS2 using the bent crystals already installed in the SPS is presented. Details
of the concept, simulations and measurements carried out with beam are
presented, before the outlook for the future is discussed.Comment: 4 pages, 7 figures, submitted to to International Particle
Accelerator Conference (IPAC) 2017 in Copenhagen, Denmar
Anatomical and histological observations of the reproductive tract in males and females of Tamandua tetradactyla (Myrmecophagidae: Xenarthra)
To the Xenarthra superorder belongs the anteater (Tamandua tetradactyla) member of the Myrmecophagidae family. Because of the habitat fragmentation, local hunting and their usage as a pet, it?s has been categorized as ?potentially vulnerable? in Argentina. Anatomical dissections and morphometric studies were performed; histological and sperm morphometric were made by light and electron microscopy in reproductive tract of 5 females and 4 males. Differentiation of the external genitalia, between sexes, is difficult: females had a slit of the vulva occupying the entire body, while males had a terminal orifice near the tip of the penis. The conical penis is located adjacent to the anus and is composed mostly of dense connective tissue, the corpus spongiosum was less developed in its upper part and the distal end was not forming a glans. The testicles are located internally in the pelvic cavity and connected by a layer of visceral peritoneum. The ovaries were covered by a simple cubic epithelium and present a medulla surrounded by the cortex. The uterus was simple, pear-shaped and dorsoventrally flattened. Histological studies showed an urogenital sinus instead of a real vagina, the cervix was elongated and was called utero-vaginal canal. Between the cervix and the urogenital sinus all females showed a biperforated membranous septum, similar to an hymen.Fil: Rossi, L.F. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Biología Cromosómica; ArgentinaFil: Rhon Calderón, E. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Biología Cromosómica; ArgentinaFil: Alonso, F.M. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Biología Cromosómica; ArgentinaFil: Luaces, J.P. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Biología Cromosómica; ArgentinaFil: Merani, M.S. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Biología Cromosómica; ArgentinaEl oso melero (Tamandua tetradactyla) pertenece a la familia Myrmecophagidae del superorden Xenarthra. La fragmentación del hábitat, la caza local y el mascotismo, lo ubican en la categorización ?potencialmente vulnerable? en Argentina. Para la aplicación a futuro de protocolos de biotecnología reproductiva en programas de manejo y conservación de gametos se realizaron disecciones anatómicas, estudios histológicos y de morfometría espermática (mediante microscopia óptica y electrónica) en tractos reproductores de 5 hembras y 4 machos. La diferenciación de la genitalia externa entre sexos resulta dificultosa: las hembras presentan una hendidura longitudinal y los machos presentan un orificio terminal en la punta del pene. El pene, contiguo al ano, está formado mayormente por tejido conectivo denso, el cuerpo esponjoso esta menos desarrollado en su parte superior y el extremo distal no forma un glande. Los testículos están ubicados internamente en la cavidad pélvica unidos por una capa del peritoneo visceral.\nLos ovarios presentan una serosa de epitelio simple cúbico y zona medular rodeada por la corteza. El útero es simple y dorso-ventralmente aplanado. Los estudios histológicos evidenciaron un seno urogenital en vez de una verdadera vagina, el cérvix fue elongado y fue denominado canal utero-vaginal. Entre este último y el seno urogenital, todas las hembras presentaron un tabique membranoso biperforado semejante a un himen
Calorimetric and transport investigations of CePd_{2+x}Ge_{2-x} (x=0 and 0.02) up to 22 GPa
The influence of pressure on the magnetically ordered CePd_{2.02}Ge_{1.98}
has been investigated by a combined measurement of electrical resistivity,
, and ac-calorimetry, C(T), for temperatures in the range 0.3 K<T<10 K
and pressures, p, up to 22 GPa. Simultaneously CePd_2Ge_2 has been examined by
down to 40 mK. In CePd_{2.02}Ge_{1.98} and CePd_2Ge_2 the magnetic
order is suppressed at a critical pressure p_c=11.0 GPa and p_c=13.8 GPa,
respectively. In the case of CePd_{2.02}Ge_{1.98} not only the temperature
coefficient of , A, indicates the loss of magnetic order but also the
ac-signal recorded at low temperature. The residual
resistivity is extremely pressure sensitive and passes through a maximum and
then a minimum in the vicinity of p_c. The (T,p) phase diagram and the
A(p)-dependence of both compounds can be qualitatively understood in terms of a
pressure-tuned competition between magnetic order and the Kondo effect
according to the Doniach picture. The temperature-volume (T,V) phase diagram of
CePd_2Ge_2 combined with that of CePd_2Si_2 shows that in stoichiometric
compounds mainly the change of interatomic distances influences the exchange
interaction. It will be argued that in contrast to this the much lower
p_c-value of CePd_{2.02}Ge_{1.98} is caused by an enhanced hybridization
between 4f and conduction electrons.Comment: 9 pages, 7 figure
Evaluation of the fourier frequency spectrum peaks of milk electrical conductivity signals as indexes to monitor the dairy goats’ health status by on-line sensors
The aim of this study is a further characterization of the electrical conductivity (EC) signal of goat milk, acquired on-line by EC sensors, to identify new indexes representative of the EC variations that can be observed during milking, when considering not healthy (NH) glands. Two foremilk gland samples from 42 Saanen goats, were collected for three consecutive weeks and for three different lactation stages (LS: 0\u201360 Days In Milking (DIM); 61\u2013120 DIM; 121\u2013180 DIM), for a total amount of 1512 samples. Bacteriological analyses and somatic cells counts (SCC) were used to define the health status of the glands. With negative bacteriological analyses and SCC 1,000,000 cells/mL, glands were classified as NH. For each milk EC signal, acquired on-line and for each gland considered, the Fourier frequency spectrum of the signal was calculated and three representative frequency peaks were identified. To evaluate data acquired a MIXED procedure was used considering the HS, LS and LS
7 HS as explanatory variables in the statistical model.Results showed that the studied frequency peaks had a significant relationship with the gland\u2019s health status. Results also explained how the milk EC signals\u2019 pattern change in case of NH glands. In fact, it is characterized by slower fluctuations (due to the lower frequencies of the peaks) and by an irregular trend (due to the higher amplitudes of all the main frequency peaks). Therefore, these frequency peaks could be used as new indexes to improve the performances of algorithms based on multivariate models which evaluate the health status of dairy goats through the use of gland milk EC sensors
Preliminary evaluation of a nest usage sensor to detect double nest occupations of laying hens
Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens' welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage "sensor", based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices
- …