Gas Loss by Ram Pressure Stripping and Internal Feedback From Low Mass Milky Way Satellites

The evolution of dwarf satellites of the Milky Way is affected by the combination of ram pressure and tidal stripping, and internal feedback from massive stars. We investigate gas loss processes in the smallest satellites of the Milky Way using three-dimensional, high resolution, idealized wind tunnel simulations, accounting for gas loss through both ram pressure stripping and expulsion by supernova feedback. Using initial conditions appropriate for a dwarf galaxy like Leo T, we investigate whether or not environmental gas stripping and internal feedback can quench these low mass galaxies on the expected timescales, shorter than 2 Gyr. We find that supernova feedback contributes negligibly to the stripping rate for these low star formation rate galaxies. However, we also find that ram pressure stripping is less efficient than expected in the stripping scenarios we consider. Our work suggests that, although ram pressure stripping can eventually completely strip these galaxies, other physics is likely at play to reconcile our computed stripping times with the rapid quenching timescales deduced from observations of low mass Milky Way dwarf galaxies. We discuss the roles additional physics may play in this scenario, including host-satellite tidal interactions, cored vs. cuspy dark matter profiles, reionization, and satellite pre-processing. We conclude that a proper accounting of these physics together is necessary to understand the quenching of low mass Milky Way satellites.Comment: 16 pages, 7 figures. Accepted for publication in Ap

Dynamical Properties of Molecular-forming Gas Clumps in Galaxies at the Epoch of Reionization

We study the properties of molecular-forming gas clumps (MGCs) at the epoch of reionization using cosmological zoom-in simulations. We identify MGCs in a z=6 prototypical galaxy ("Althaea") using an H2 density-based clump finder. We compare their mass, size, velocity dispersion, gas surface density, and virial parameter (alpha_vir) to observations. In Althaea, the typical MGC mass and size are Mgas=10^6.5 Msun and R=45-100 pc, which are comparable to those found in nearby spirals and starburst galaxies. MGCs are highly supersonic and supported by turbulence, with rms velocity dispersions of sigma_gas=20-100 km s^-1 and pressure of P/k_B=10^7.6 K cm^-3 (i.e., >1000x with respect to the Milky Way), similar to those found in nearby and z~2 gas-rich starburst galaxies. In addition, we perform stability analysis to understand the origin and dynamical properties of MGCs. We find that MGCs are globally stable in the main disk of Althaea. Densest regions where star formation is expected to take place in clouds and cores on even smaller scales instead have lower alpha_vir and Toomre-Q values. Detailed studies of the star-forming gas dynamics at the epoch of reionization thus require a spatial resolution of <40 pc (=0.01"), which is within reach with the Atacama Large (sub-)Millimeter Array and the Next Generation Very Large Array.Comment: 16 pages, 10 figures, ApJ accepte

Romantic and sexual behavior in young adolescents : repeated surveys in a population-based cohort

Adverse outcomes of teenage sexual activity are common in the United Kingdom. We used a computer-assisted interview to ask young adolescents aged 11-12 years (N = 6856) and 12 -13 years (N = 6801) who were part of the Avon Longitudinal Study of Parents and Children about romantic and intimate behaviors. 24% of 11-12 year olds and 41% of 12-13 year olds reported holding hands and 17% and 32% respectively reported having been kissed on the mouth. A minority of 12-13 year olds reported sexual behavior including intercourse. The majority of participants who reported intimate sexual behavior did not regret it. Boys reported all activities more than girls and were less likely to express regret. Our findings suggest that the timing and content of sex education should take into account the frequency with which young people are experimenting with sexual behaviors

Inheritance of single copy nuclear genes (SCNGs) in artificial hybrids of Hesperocyparis arizonica x H. macrocarpa: Potential for utilization in the detection of hybridization in natural populations

Analyses were performed on 18 artificial hybrids from a cross of Hesperocyparis arizonica (male parent) x H. macrocarpa (female parent) using 9 single copy nuclear genes (SCNGs). Three SCNG were found to be informative: myb, 4CL and CnAIB2. Gene myb contained 5 variable sites, of which site 89 was homozygous (CC, TT) as was site 261 (GG, AA) and useful for the detection of hybridization. All 18 hybrids were heterozygous (CT and GA) at these 2 sites as predicted in hybrids. 4CL contained 8 variable sites, of which 1 site (591) was homozygous (TT, CC) and all 18 hybrids were heterozygous (TC) at this site as expected. CnAIP2 had two variable sites: 301 (AA, AC) and 554 (AG, AA). For site 301, 8 hybrids were AA, and 10 were AC as expected. For site 554, 10 hybrids were AA and 8 were AG, so neither would be useful for unequivocally identifying hybrids. The inheritance of variable sites for the three SCNGs followed simple co-occurrence. Examination of myb in the 18 hybrids revealed 2 cases of cross-over in the pollen gametes

Controlling photonic spin Hall effect via exceptional points

The photonic spin Hall effect (SHE), featured by a spin-dependent transverse shift of an impinging optical beam driven by its polarization handedness, has many applications including precise metrology and spin-based nanophotonic devices. It is highly desirable to control and enhance the photonic SHE. However, such a goal remains elusive, due to the weak spin-orbit interaction of light, especially for systems with optical loss. Here we reveal a flexible way to modulate the photonic SHE via exceptional points, by exploiting the transverse shift in a parity-time (PT) symmetric system with balanced gain and loss. The underlying physics is associated with the near-zero value and abrupt phase jump of the reflection coefficients at exceptional points. We find that the transverse shift is zero at exceptional points, but it is largely enhanced in their vicinity. In addition, the transverse shift switches its sign across the exceptional point, resulting from spontaneous PT-symmetry breaking. Due to the sensitivity of transverse shift at exceptional points, our work also indicates that the photonic SHE can enable a precise way to probe the location of exceptional point in photonic systems.Comment: 14 pages, 4 figure

Educational Gerontology

The aging population in the developed world has implied increasing age diversity in the workforce of organizations. Consequently, mutual perceptions about one’s coworkers and age discrimination are becoming increasingly important. This study aims to explore how perceptions about older workers’ work (un)adaptability, work effectiveness, and workplace age discrimination vary according to participants’ psychosocial factors, such as age group, gender, education level, and work sector. This study included a sample of 453 workers in Portugal, diverse in terms of age, gender, education level, and work sector. Four different instruments were used: (a) a sociodemographic questionnaire; (b) an older workers’ Work Adaptability scale; (c) an older workers’ Work Effectiveness Scale and; (d) the Workplace Age Discrimination Scale (WADS). Results: Middle-aged and older participants perceive older workers as more adaptable than younger participants. The oldest group of participants perceives older workers to be more workeffective and experience the highest levels of age discrimination in the workplace, when compared to the other age groups. Also, participants with lower levels of education tend to perceive higher levels of workplace age discrimination, when compared to participants with high school and higher education. Conclusions: Generational perceptions in the workplace are perceived by workers differently, hence organizations should implement age management strategies to address age discrimination, particularly due to the increasing proportion of older workers.info:eu-repo/semantics/publishedVersio

Sexual well-being in older adults: A qualitative study with older adults from Portugal and Slovenia

Introduction Beyond living longer, it is increasingly important to live with more and better health during aging; sexual well-being was found to contribute to health and well-being in old age and is highly under-researched in the older population. This study aims to analyze sexual well-being in a cross-cultural way through older Portuguese and Slovenian older samples. Methods We interviewed 136 older participants with an average age of 71.6 years old. Participants were Portuguese and Slovenian and lived in the community. Participants were subjected to semi-structured interviews and these were subjected to a content analysis process. Results The content analysis indicated nine themes related to sexual well-being: self-reported good health; demonstrations of love; non-sexual joint activities; overall well-being and quality of life; partner support; positive self-image; being independent and active; sexual compatibility; and masturbation. Conclusions Portuguese older adults experience their sexual well-being associated mainly with self-reported good health and demonstrations of love, while Slovenians older adults associate their sexual well-being mainly with non-sexual joint activities and overall well-being and quality of life. Policy Implications The themes found in this study are fundamental evidence for cultural interventions and guidelines outlining in the context of sexual health in aging, mainly due to the scarcity of knowledge of sexual well-being among older adults.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

The Beacon Community Centers Middle School Initiative: Report on Implementation and Youth Experience in the Initiative's Second Year

Evaluates the second year of an initiative to offer fifth-to-eighth graders structured out-of-school-time programs. Looks at implementation, such as engagement, staffing, and activities; youths' social and educational development; and underlying factors