Modeling the buckling and delamination of thin films

I study numerically the problem of delamination of a thin film elastically attached to a rigid substrate. A nominally flat elastic thin film is modeled using a two-dimensional triangular mesh. Both compression and bending rigidities are included to simulate compression and bending of the film. The film can buckle (i.e., abandon its flat configuration) when enough compressive strain is applied. The possible buckled configurations of a piece of film with stripe geometry are investigated as a function of the compressive strain. It is found that the stable configuration depends strongly on the applied strain and the Poisson ratio of the film. Next, the film is considered to be attached to a rigid substrate by springs that can break when the detaching force exceeds a threshold value, producing the partial delamination of the film. Delamination is induced by a mismatch of the relaxed configurations of film and substrate. The morphology of the delaminated film can be followed and compared with available experimental results as a function of model parameters. `Telephone-cord', polygonal, and `brain-like' patterns qualitatively similar to experimentally observed configurations are obtained in different parameter regions. The main control parameters that select the different patterns are the mismatch between film and substrate and the degree of in-plane relaxation within the unbuckled regions.Comment: 8 pages, 10 figure

Electron Temperature of Ultracold Plasmas

We study the evolution of ultracold plasmas by measuring the electron temperature. Shortly after plasma formation, competition between heating and cooling mechanisms drives the electron temperature to a value within a narrow range regardless of the initial energy imparted to the electrons. In agreement with theory predictions, plasmas exhibit values of the Coulomb coupling parameter $\Gamma$ less than 1.Comment: 4 pages, plus four figure

Late Holocene Tsunami Deposits at Salt Creek, Washington, USA

We interpret two thin sand layers in the estuarine marsh at Salt Creek, on the southern shore of the Strait of Juan de Fuca, as the products of tsunamis propagated by earthquakes at the Cascadia subduction zone. The sand layers extend for about 60 m along the left bank of the creek about 800 m from the mouth, and can be traced to the base of a nearby upland area. One layer is exposed in the creek bank about 400 m further upstream, but they are only patchily distributed in the rest of the central area of the marsh. Both layers contain brackish-marine epipsammic diatoms. The lower sand layer marks a sharp contact between intertidal peaty mud and overlying mud, perhaps reflecting modest coseismic subsidence in association with tsunami deposition, but little or no change in the bracketing sediment occurs in association with the upper sand layer. The ages of the sand layers are not closely constrained, but were most likely deposited by tsunamis generated by great earthquakes at the Cascadia subduction zone about 1650 and 1300 years ago. The Cascadia great earthquake of AD1700 may have induced slight subsidence in the marsh, but no tsunami deposit was detected at the inferred contact. The absence of deposits from the marsh immediately inland of the 4 m-high barrier beach indicates that the largest tsunamis in the late Holocene at this site have not overtopped the barrier, which suggests that these tsunamis were likely only 2-3 m high

Triggering social interactions:chimpanzees respond to imitation by a humanoid robot and request responses from it

Even the most rudimentary social cues may evoke affiliative responses in humans and promote socialcommunication and cohesion. The present work tested whether such cues of an agent may also promotecommunicative interactions in a nonhuman primate species, by examining interaction-promoting behavioursin chimpanzees. Here, chimpanzees were tested during interactions with an interactive humanoid robot, whichshowed simple bodily movements and sent out calls. The results revealed that chimpanzees exhibited twotypes of interaction-promoting behaviours during relaxed or playful contexts. First, the chimpanzees showedprolonged active interest when they were imitated by the robot. Second, the subjects requested ‘social’responses from the robot, i.e. by showing play invitations and offering toys or other objects. This study thusprovides evidence that even rudimentary cues of a robotic agent may promote social interactions inchimpanzees, like in humans. Such simple and frequent social interactions most likely provided a foundationfor sophisticated forms of affiliative communication to emerge

POLICY IMPLICATIONS OF RESTRICTED ACCESS STRATEGIES FOR MULTISPECIES FISHERIES

The commercial fishery that primarily targets king mackerel, stone crab, snappers, groupers and spiny lobster in Monroe and Collier counties is one of the most important commercial fisheries in Florida. These species currently face problems of overfishing and/or over capitalization. A dual-based restricted profit function is used to estimate the economic and technical interactions that exist in this multi-species fishery, primarily using own-price and cross-price elasticities of supply. It is found that the production technology does not exhibit input-output separability and nonjointness-in-inputs over all species groups. This result suggests that these key species may be more efficiently managed as a group, rather than with the use of existing single species regulations. Spiny lobster and stone crab, the dominant value species in the fishery, are shown to have very elastic substitution relationships with king mackerel.Resource /Energy Economics and Policy,

Coherence properties of the two-dimensional Bose-Einstein condensate

We present a detailed finite-temperature Hartree-Fock-Bogoliubov (HFB) treatment of the two-dimensional trapped Bose gas. We highlight the numerical methods required to obtain solutions to the HFB equations within the Popov approximation, the derivation of which we outline. This method has previously been applied successfully to the three-dimensional case and we focus on the unique features of the system which are due to its reduced dimensionality. These can be found in the spectrum of low-lying excitations and in the coherence properties. We calculate the Bragg response and the coherence length within the condensate in analogy with experiments performed in the quasi-one-dimensional regime [Richard et al., Phys. Rev. Lett. 91, 010405 (2003)] and compare to results calculated for the one-dimensional case. We then make predictions for the experimental observation of the quasicondensate phase via Bragg spectroscopy in the quasi-two-dimensional regime.Comment: 9 pages, 9 figure

A qualitative study of men’s recollections of growing up with father absence: childhood father figures and family resilience

© 2017 Informa UK Limited, trading as Taylor & Francis Group. Background: Families come in many forms and single parent women headed households are common with nurses being well positioned to provide support for these women and their children. For children growing up in lone parent households, the nature of family relationships and the availability of a social support network are important factors in reducing developmental risks. Aim: The aim of this study was to explore adult men’s recollections of growing up in a father-absent home. Design: This study utilised a qualitative methodology. Methods: Semi-structured interviews were conducted with 21 adult men who grew up in a father-absent home due to family discord. Interview transcripts were thematically analysed using an inductive approach. Findings: Analysis of the interview transcripts revealed two themes relating to childhood father figures and family relational networks. For some men, ambivalent, violent or unavailable father figures stepped into the void created by the absent father. Others experienced positive father figures or multigenerational relationships, which provided positive relational supports and attachments. Conclusion: The findings illuminate the dynamics of family resilience and provide important insights for nurses and other family healthcare workers

“Being a father”: constructions of fatherhood by men with absent fathers

© 2018 Informa UK Limited, trading as Taylor & Francis Group Family dynamics and parenting styles are influential on children's wellbeing [Walsh, F. (2016). Strengthening family resilience (3rd ed.). New York: Guilford Press]. Additionally, childhood experiences and how an individual experienced being parented can impact on how individuals as mothers and fathers choose to parent their own children [Herland, M. D., Hauge, M.-I., & Helegland, I. M. (2015). Balancing fatherhood: Experiences of fatherhood among men with a difficult past. Qualitative Social Work, 14(2), 242–258]. However, growing up in a home with an absent parent may create challenges associated with parenting for individuals, due to not having these experiences themselves. Therefore, the article reports findings on men who grew up in a father-absent household and how their experiences influenced their understanding of fatherhood and becoming a father. Twenty-one men participated in this qualitative study. Findings revealed that although men felt unprepared for fatherhood they attempted to learn to be a father and expressed the importance of not wanting their children to experience father absence. The study findings provide important insights in the provision of support for fathers who have experienced father absence

Applied Remote Sensing Program (ARSP)

There are no author-identified significant results in this report

V39: an unusual object in the field of IC 1613

The variable star V39 in the field of IC 1613 is discussed in the light of the available photometric and new spectroscopic data. It has strong emission Balmer lines, and the observed characteristics could be explained by a W Vir pulsating star with a period of 14.341 d, located at more than 115 kpc, that is in the very outer halo of our Galaxy. It should have an apparent companion, a long period (1118d) red variable, belonging to IC 1613. The main uncertainty in this interpretation is an emission feature at 668.4 nm, which we tentatively identified as a He I line.Comment: 5 pages; accepted for publication in Astronomy & Astrophysic