Experimental evidence for the formation of liquid saline water on Mars

Evidence for deliquescence of perchlorate salts has been discovered in the Martian polar region while possible brine flows have been observed in the equatorial region. This appears to contradict the idea that bulk deliquescence is too slow to occur during the short periods of the Martian diurnal cycle during which conditions are favorable for it. We conduct laboratory experiments to study the formation of liquid brines at Mars environmental conditions. We find that when water vapor is the only source of water, bulk deliquescence of perchlorates is not rapid enough to occur during the short periods of the day during which the temperature is above the salts' eutectic value, and the humidity is above the salts' deliquescence value. However, when the salts are in contact with water ice, liquid brine forms in minutes, indicating that aqueous solutions could form temporarily where salts and ice coexist on the Martian surface and in the shallow subsurface. Key Points The formation of brines at Martian conditions was studied experimentally Bulk deliquescence from water vapor is too slow to occur diurnally on Mars Brines form in minutes when salts are placed in direct contact with icePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108051/1/grl51829.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108051/2/2014GL060302_AuxiliaryMaterialreadme.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108051/3/ts01.pd

Patterns of the ground states in the presence of random interactions: nucleon systems

We present our results on properties of ground states for nucleonic systems in the presence of random two-body interactions. In particular we present probability distributions for parity, seniority, spectroscopic (i.e., in the laboratory framework) quadrupole moments and $\alpha$ clustering in the ground states. We find that the probability distribution for the parity of the ground states obtained by a two-body random ensemble simulates that of realistic nuclei: positive parity is dominant in the ground states of even-even nuclei while for odd-odd nuclei and odd-mass nuclei we obtain with almost equal probability ground states with positive and negative parity. In addition we find that for the ground states, assuming pure random interactions, low seniority is not favored, no dominance of positive values of spectroscopic quadrupole deformation, and no sign of $\alpha$-cluster correlations, all in sharp contrast to realistic nuclei. Considering a mixture of a random and a realistic interaction, we observe a second order phase transition for the $\alpha$-cluster correlation probability.Comment: 7 page

Unstable solitons on noncommutative tori and D-branes

We describe a class of exact solutions of super Yang-Mills theory on even-dimensional noncommutative tori. These solutions generalize the solitons on a noncommutative plane introduced in hep-th/0009142 that are conjectured to describe unstable D2p-D0 systems. We show that the spectrum of quadratic fluctuations around our solutions correctly reproduces the string spectrum of the D2p-D0 system in the Seiberg-Witten decoupling limit. In particular the fluctuations correctly reproduce the 0-0 string winding modes. For p=1 and p=2 we match the differences between the soliton energy and the energy of an appropriate SYM BPS state with the binding energies of D2-D0 and D4-D0 systems. We also give an example of a soliton that we conjecture describes branes of intermediate dimension on a torus such as a D2-D4 system on a four-torus.Comment: 22 pages, Latex; v.2: references adde

Uukuniemi Phlebovirus Assembly and Secretion Leave a Functional Imprint on the Virion Glycome

Uukuniemi virus (UUKV) is a model system for investigating the genus Phlebovirus of the Bunyaviridae. We report the UUKV glycome, revealing differential processing of the Gn and Gc virion glycoproteins. Both glycoproteins display poly-N-acetyllactosamines, consistent with virion assembly in the medial Golgi apparatus, whereas oligomannose-type glycans required for DC-SIGN-dependent cellular attachment are predominant on Gc. Local virion structure and the route of viral egress from the cell leave a functional imprint on the phleboviral glycome

The impact of COVID-19 restrictions on perceived health and wellbeing of adult Australian sport and physical activity participants

Individuals’ access to sport and physical activity has been hampered due to COVID-19 lockdown restrictions. In Australia participation in community sport was cancelled during lockdowns. There is limited research on the impact of sport participation restrictions on the health and wellbeing of adults. Aim The aim of this study was to investigate the perceived health and wellbeing of a sample of predominantly active Australian adults, both during COVID-19 and in comparison with one year earlier (pre COVID-19). Methods A survey was conducted during the first COVID-19 restrictions and lockdowns in Australia in May–June 2020. It was distributed by national and state sporting organisations and through researchers’ social media accounts. This particular paper focuses on adults aged 18–59 years. The survey collected information on participant demographics, the sport and physical activity patterns pre- COVID-19, and health and wellbeing outcomes during COVID-19 lockdown and compared to one year earlier. The health measures were cross-tabulated against the demographic and sport and physical activity variables, and group profiles compared with chi-square tests. Scales were derived from three wellbeing questions, and group differences were analysed by t-tests and F-tests. Results The survey sample included 1279 men and 868 women aged 18–59 years. Most (67%) resided in metropolitan cities. The great majority (83%) were sport participants. During COVID-19 lockdown men were significantly more likely than women to report worse or much worse general (p = 0.014), physical (p = 0.015) and mental health (p = 0.038) and lower life satisfaction (p = 0.016). The inactive adults were significantly more likely to report poorer general health (p = 0.001) and physical health (p = 0.001) compared to active adults. The younger age cohort (18–29 years) were significantly more likely to report poorer general wellbeing (p < 0.001), and lower life satisfaction (p < 0.001) compared to the older age groups. Conclusion It seems that the absence of playing competitive sport and training with friends, teams and within clubs has severely impacted males and younger adults in particular. Sports clubs provide an important setting for individuals’ health and wellbeing which is why clubs require the capacity to deliver sport and individuals may need to regain the motivation to return

The impact of prolonged disorders of consciousness on the occupational life of family members

The impact of vegetative state (VS) and minimally conscious states (MCSs) on an individual is devastating. VS and MCSs may be transitional towards recovery, but may become permanent. Although devastating for the individual the nature of these conditions also has a profound effect on the family. This study examined the impact on the family member and the changes in the individuals’ occupation. Six participants (spouses, partners or parents) were recruited to the study. Mixed methods were adopted to meet the requirements of the research and participants. Data were collected at 6 and 12 months post-injury, using time diaries, a questionnaire and semi-structured interviews. At 6 months post-injury the greatest amount of carers’ time was allocated to occupations involving the person in a Disorder of Consciousness and less time to social and leisure activities. Participants had difficulty viewing the future, lacked the desire or capacity to engage in previously enjoyed activities. At 12 months those impacts were still evident although changing. The transition to balanced occupational activity is slow, requiring a number of catalysts to change. A conceptual framework for a return to balance is provided, and guidance on advice from family members to families in a similar situation is given

Dynamic modeling of mean-reverting spreads for statistical arbitrage

Statistical arbitrage strategies, such as pairs trading and its generalizations, rely on the construction of mean-reverting spreads enjoying a certain degree of predictability. Gaussian linear state-space processes have recently been proposed as a model for such spreads under the assumption that the observed process is a noisy realization of some hidden states. Real-time estimation of the unobserved spread process can reveal temporary market inefficiencies which can then be exploited to generate excess returns. Building on previous work, we embrace the state-space framework for modeling spread processes and extend this methodology along three different directions. First, we introduce time-dependency in the model parameters, which allows for quick adaptation to changes in the data generating process. Second, we provide an on-line estimation algorithm that can be constantly run in real-time. Being computationally fast, the algorithm is particularly suitable for building aggressive trading strategies based on high-frequency data and may be used as a monitoring device for mean-reversion. Finally, our framework naturally provides informative uncertainty measures of all the estimated parameters. Experimental results based on Monte Carlo simulations and historical equity data are discussed, including a co-integration relationship involving two exchange-traded funds.Comment: 34 pages, 6 figures. Submitte

A Quantum-Mechanical Equivalent-Photon Spectrum for Heavy-Ion Physics

In a previous paper, we calculated the fully quantum-mechanical cross section for electromagnetic excitation during peripheral heavy-ion collisions. Here, we examine the sensitivity of that cross section to the detailed structure of the projectile and target nuclei. At the transition energies relevant to nuclear physics, we find the cross section to be weakly dependent on the projectile charge radius, and to be sensitive to only the leading momentum-transfer dependence of the target transition form factors. We exploit these facts to derive a quantum-mechanical ``equivalent-photon spectrum'' valid in the long-wavelength limit. This improved spectrum includes the effects of projectile size, the finite longitudinal momentum transfer required by kinematics, and the response of the target nucleus to the off-shell photon.Comment: 19 pages, 5 figure