Getting a kick out of the stellar disk(s) in the galactic center

Recent observations of the Galactic center revealed a nuclear disk of young OB stars, in addition to many similar outlying stars with higher eccentricities and/or high inclinations relative to the disk (some of them possibly belonging to a second disk). Binaries in such nuclear disks, if they exist in non-negligible fractions, could have a major role in the evolution of the disks through binary heating of this stellar system. We suggest that interactions with/in binaries may explain some (or all) of the observed outlying young stars in the Galactic center. Such stars could have been formed in a disk, and later on kicked out from it through binary related interactions, similar to ejection of high velocity runaway OB stars in young clusters throughout the galaxy.Comment: 2 pages, 2 figs. To be published in the proceedings of the IAU 246 symposium on "Dynamical evolution of dense stellar systems

ANALYSIS OF SESAME PROTEINS ISOLATE (SESAMUM INDICUM L) WITH WATER AND SALT TREATMENT

Objective: The aim of this study was to obtain protein isolate from sesame using alkaline pH at different pHs of precipitation with water and salt andto analyze protein isolate with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).Methods: Sesame protein isolates were obtained using isoelectric precipitation method at different pHs using water and salt as solvents. Proteinswere analyzed using native-PAGE and SDS-PAGE.Results: A yield of 14,727% ± 0.3 of protein isolate of defatted sesame flour at pH 7.0 with a 47.4% ± 0.6 of protein was obtained. The yield of proteinisolate using water and salt was similar. Polypeptides profile is between 6.5 and 50 kDa.Conclusions: Sesame seed is a good source of proteins. Globulins and albumins were identified in the sesame protein isolate in the presence of waterand salt.Keywords: Sesame, Protein isolate, Proteins, Globulins and albumins

Voluntary suppression of associated activity decreases force steadiness in the active hand

Unilateral muscle contractions are often accompanied by the activation of the ipsilateral hemisphere, producing associated activity (AA) in the contralateral homologous muscles. However, the functional role of AA is not fully understood. We determined the effects of voluntary suppression of AA in the first dorsal interosseous (FDI), on force steadiness during a constant force isometric contraction of the contralateral FDI. Participants (n = 17, 25.5 years) performed two trials of isometric FDI contractions as steadily as possible. In Trial 1, they did not receive feedback or explicit instructions for suppressing the AA in the contralateral homologous FDI. In Trial 2, participants received feedback and were asked to voluntarily suppress the AA in the contralateral nontarget FDI. During both trials, corticospinal excitability and motor cortical inhibition were measured. The results show that participants effectively suppressed the AA in the nontarget contralateral FDI (-71%), which correlated with reductions in corticospinal excitability (-57%), and the suppression was also accompanied by increases in inhibition (27%) in the ipsilateral motor cortex. The suppression of AA impaired force steadiness, but the decrease in force steadiness did not correlate with the magnitude of suppression. The results show that voluntary suppression of AA decreases force steadiness in the active hand. However, due to the lack of association between suppression and decreased steadiness, we interpret these data to mean that specific elements of the ipsilateral brain activation producing AA in younger adults are neither contributing nor detrimental to unilateral motor control during a steady isometric contraction

Pedagogical Practice – Index of Readiness of Future Physics Teacher to Professional Activity

У статті проаналізовано організаційно-методичні засади педагогічної практики у вищому навчальному закладі на даний час, розкрито її значення в системі професійного становлення майбутнього вчителя фізики. Зазначено, що ефективне проведення педпрактики залежить від належного рівня організації і управління діяльністю студентів. Обґрунтовано, що результати педагогічної практики виступають показником готовності студента до майбутньої професійної діяльності та одночасно вказують на недоліки і прогалини у знаннях студентів, на які необхідно звернути особливу увагу під час фахової підготовки. Описано основні розділи «Програми педагогічної практики» для студентів-майбутніх вчителів фізики (4-й курс), розробленої авторами статті у співавторстві з колективом досвідчених викладачів кафедри. Окреслено перспективи педагогічної практики студентів у зв’язку з реформуванням вищої освіти в Україні. Висвітлено деякі особливості організації педагогічної практики у вищих навчальних закладах різних країн світу.The article analyzes organizational-methodical bases of pedagogical practice in higher education at the present time, revealed its importance in the system of professional formation of future teachers of physics. Noted that effective implementation of the internship depends on the appropriate level of the organization and management of students. It is proved that the results of the pedagogical practices act as an indicator of students 'readiness for future professional activity and at the same time indicate shortcomings and gaps in students' knowledge that need special attention in training. Describes the main sections of "teaching practice Program" for students-future physics teachers (4th year) developed by the authors in collaboration with a team of experienced teachers of the Department. Perspectives of pedagogical practice of students in connection with the reform of higher education in Ukraine. Highlight some features of the organization of pedagogical practice in higher education institutions around the world

The origin of runaway stars

Milli-arcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of some of the nearest runaway stars and pulsars to determine their site of origin. The orbits of the runaways AE Aurigae and mu Columbae and of the eccentric binary iota Orionis intersect each other about 2.5 Myr ago in the nascent Trapezium cluster, confirming that these runaways were formed in a binary-binary encounter. The path of the runaway star zeta Ophiuchi intersects that of the nearby pulsar PSR J1932+1059, about 1 Myr ago, in the young stellar group Upper Scorpius. We propose that this neutron star is the remnant of a supernova that occurred in a binary system which also contained zeta Oph, and deduce that the pulsar received a kick velocity of about 350 km/s in the explosion. These two cases provide the first specific kinematic evidence that both mechanisms proposed for the production of runaway stars, the dynamical ejection scenario and the binary-supernova scenario, operate in nature.Comment: 5 pages, including 2 eps-figures and 1 table, submitted to the ApJ Letters. The manuscript was typeset using aaste

Hypervelocity Stars III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center

We report the discovery of 3 new unbound hypervelocity stars (HVSs), stars traveling with such extreme velocities that dynamical ejection from a massive black hole (MBH) is their only suggested origin. We also detect a population of possibly bound HVSs. The significant asymmetry we observe in the velocity distribution -- we find 26 stars with v_rf > 275 km/s and 1 star with v_rf < -275 km/s -- shows that the HVSs must be short-lived, probably 3 - 4 Msun main sequence stars. Any population of hypervelocity post-main sequence stars should contain stars falling back onto the Galaxy, contrary to the observations. The spatial distribution of HVSs also supports the main sequence interpretation: longer-lived 3 Msun HVSs fill our survey volume; shorter-lived 4 Msun HVSs are missing at faint magnitudes. We infer that there are 96 +- 10 HVSs of mass 3 - 4 Msun within R < 100 kpc, possibly enough HVSs to constrain ejection mechanisms and potential models. Depending on the mass function of HVSs, we predict that SEGUE may find up to 5 - 15 new HVSs. The travel times of our HVSs favor a continuous ejection process, although a ~120 Myr-old burst of HVSs is also allowed.Comment: 10 pages, 8 figures, accepted to ApJ, minor revision

Long-term effectiveness of a novel intra-oral electro-stimulator for the treatment of dry mouth in patients with Sjogren's syndrome: A randomised sham-controlled feasibility study (LEONIDAS-1)

BACKGROUND: Effective treatments for dry mouth of Sjogren's syndrome are limited and hampered by adverse effects. The aim of LEONIDAS-1 was to explore the feasibility of salivary electrostimulation in individuals with primary Sjogren's syndrome, as well as parameters required to inform the design of a future phase III trial. METHODS: Multicentre, parallel-group, double-blind, randomised sham-controlled trial in two UK centres. Participants were randomised (1:1, computer-generated) to active or sham electrostimulation. The feasibility outcomes included screening/eligibility ratio, consent, and recruitment and drop-out rates. Preliminary efficacy outcome included dry mouth visual analogue scale, Xerostomia Inventory, the EULAR Sjögren's syndrome patient reported index-Q1, and unstimulated sialometry. RESULTS: Forty-two individuals were screened, of whom 30 (71.4%) met the eligibility criteria. All eligible individuals consented to recruitment. Out of the 30 randomised participants (active n = 15, sham n = 15), 4 dropped out and 26 (13 vs. 13) completed all study visits as per protocol. Recruitment rate was 2.73 participants/month. At 6-month post-randomisation the difference in mean reduction in visual analogue scale, xerostomia inventory and EULAR Sjögren's syndrome patient reported index-Q1 scores between groups were 0.36 (95% CI: -0.84, 1.56), 3.31 (0.43, 6.18), and 0.23 (-1.17, 1.63), respectively; unstimulated salivary flow increased by a mean of 0.98 mL/15 min, all in favour of the active group. No adverse events were reported. CONCLUSION: LEONIDAS-1 results support progression to a phase III definitive randomised controlled trial of salivary electrostimulation in individuals with Sjogren's syndrome. Xerostomia inventory could be considered the primary patient-centred outcome measure and the corresponding observed treatment effect could inform the sample size of a future trial