820 research outputs found

    THE MONK PARAKEET AND NEW JERSEY AGRICULTURE

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    Parrots and parakeets have been brought into the United States for as long as our sailors have sailed to the distant tropics. In more recent years, the keeping of exotic pets increased to almost fad proportions. The pet shops and importers have kept the United States supplied with a vast array of these species. Among them is the Monk Parakeet. Large numbers of Monk Parakeets have been imported to satisfy the demand for parrot-like birds. The largest percentage of these birds went to pet stores and ultimately ended up in homes as pets. Unfortunately, some of these birds were released or escaped into the wild. New Jersey, in the winter of 1969-70 had its first report of wild Monk Parakeets in Middlebush. Two birds were identified as Monk Parakeets. Since then that particular flock has grown to eight or more parakeets. Although this is a small increase in three years it should be noted that the season in their native South America is the reverse of our own. It would seem that the mating season would need to be changed to coincide with the Northern Hemisphere for the young to survive. The climate in Argentina, Paraguay, Uruguay, Bolivia, and Brazil is very similar to that of New York and New Jersey. The South American habitat is 20Ā° - 48Ā° South latitude, whereas New Jersey is 30Ā° - 40Ā° North latitude. In this three year period New Jersey has gone from one loca- tion to over 35 locations with 13 nests. In general, the parakeets are located in single or small flocks. Most sightings are in the more populated areas of the State. This is a belt 25 miles wide going from New York City southwest to Delaware. There do seem to be more birds directly across from New York City and Delaware than anywhere else along this belt

    "It's more than milk, it's mental health": a case of online human milk sharing

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    Background: Milk sharing is not a new concept and occurs today via regulated human milk banks and unregulated online milk sharing groups. Exploring and understanding how, and why, mothers use these peers to peer milk sharing groups, is a vehicle to understanding how breastfeeding mothers can be tangibly supported online, adding to the literature on peer milk sharing, from a recipient's perspective. This research presents a single case example of an online breastfeeding support group use, through one mother's experiencing of seeking human donor milk. Method: This is a qualitative, exploratory study observing the attitudes, thoughts, and feelings of one mother who is seeking human donor milk through online groups. A single key case was identified, and the participant was asked to document thoughts and feelings as she searched for milk online. A telephone interview was conducted after two months, and the online page activity from the Human Milk for Human Babies Facebook group was captured for the week following the interview. The results were presented in a chronological and linear analytical approach adopting pattern matching. Results: 'Abbi' is a mother who has Polycystic Ovary Syndrome and subsequent low milk supply and sought donor breastmilk online. Online support groups introduced her to donor milk sharing, which not only supported her breastfeeding but supported her own mental health. Abbi talks of the need to build a trusting relationship with her donor, due to the lack of regulation, and the positive impact it had for her and 'Lucas', her baby. Conclusion: Considering milk sharing groups simply as tangible online support ignores the complexities around Abbi's decision to use human donor milk. Peer milk sharing online is an option for mothers, but it is surrounded by stigma amongst other mothers, professionals, and even within pro breastfeeding support groups

    Using a damper amplification factor to increase energy dissipation in structures

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    AbstractFluid dampers are an important tool for dissipating unwanted vibrations in a range of engineering structures. This paper examines the effects of amplifying the displacements transferred to a non-linear damper, to increase the effectiveness of the damper in a range of situations commonly encountered in civil engineering structures. These include, (i) the ability to ā€œfine tuneā€ the required damping for a particular size damper, (ii) the ability to have a set of the same size dampers, but with different amplification factors to achieve a specific damping task, and (iii) to increase the sensitivity of the damper to small movements which effectively extends the range over which the damper works. Through numerical simulations and experimental tests conducted on a non-linear damper, we quantify the potential advantages of adding an amplification factor and the range of parameters where the benefit to this device is significant. The example of a two-storey structure is used as a test case and real-time dynamic substructuring tests are used to assess the complete system performance using a range of different amplification factors. The results show that the structural performance is most improved for frequencies close to resonance and that the amplification factor has an effective limit that for the case considered in this study is of approximately 3. The effects of the mechanism compliance are also assessed

    Supporting brace sizing in structures with added linear viscous fluid dampers: A filter design solution

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    Viscous fluid dampers have proved to be effective in suppressing unwanted vibrations in a range of engineering structures. When dampers are fitted in a structure, a brace is typically used to attach them to the main structure. The stiffness of this brace can significantly alter the effectiveness of the damper, and in structures with multiple dampers, this can be a complex scenario to model. In this paper, we demonstrate that the effects of the brace compliance on the damper performance can be modelled by way of a first-order filter. We use this result to formulate a procedure that calculates the stiffness required by the supporting brace to provide a specified effectiveness of the damping action. The proposed procedure assumes that viscous dampers have been sized in a previous design step based on any optimal methodology in which, as is usually the case, the presence of supporting braces and their dynamic effects were neglected. Firstly considering a one degree-of-freedom system, we show that the proposed method ensures a desired level of damper efficiency for all frequencies within a selected bandwidth. Then the analysis is extended to the case of multi-degree-of-freedom systems to show that the design criteria can be applied in a straightforward and successful manner to more complex structures

    Galaxy Formation Through Filamentary Accretion at z=6.1

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    We present ALMA observations of the dust continuum and [C II] 158um line emission from the z=6.0695 Lyman Break Galaxy WMH5. These observations at 0.3" spatial resolution show a compact (~3kpc) main galaxy in dust and [C II] emission, with a 'tail' of emission extending to the east by about 5kpc (in projection). The [C II] tail is comprised predominantly of two distinct sub-components in velocity, separated from the core by ~100 and 250km/s, with narrow intrinsic widths of about 80km/s, which we call 'sub-galaxies'. The sub-galaxies themselves are extended east-west by about 3kpc in individual channel images. The [C II] tail joins smoothly into the main galaxy velocity field. The [C II] line to continuum ratios are comparable for the main and sub-galaxy positions, within a factor 2. In addition, these ratios are comparable to z~5.5 LBGs. We conjecture that the WMH5 system represents the early formation of a galaxy through the accretion of smaller satellite galaxies, embedded in a smoother gas distribution, along a possibly filamentary structure. The results are consistent with current cosmological simulations of early galaxy formation, and support the idea of very early enrichment with dust and heavy elements of the accreting material.Comment: 10 pages, 9 figures, Accepted for publication in Ap

    Dense Molecular Gas Excitation in Nuclear Starbursts at High Redshift: HCN, HNC, and HCO+(J=6-5) Emission in the z=3.91 Quasar Host of APM08279+5255

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    We report the detection of surprisingly strong HCN, HNC, and HCO+(J=6-5) emission in the host galaxy of the z=3.91 quasar APM08279+5255 through observations with CARMA. HCN, HNC, and HCO+ are typically used as star formation indicators, tracing dense molecular hydrogen gas [n(H2) > 10^5,cm^-3] within star-forming molecular clouds. However, the strength of their respective line emission in the J=6-5 transitions in APM08279+5255 is extremely high, suggesting that they are excited by another mechanism besides collisions in the dense molecular gas phase alone. We derive J=6-5 line luminosities of L'(HCN)=(4.9+/-0.6), L'(HNC)=(2.4+/-0.7), and L'(HCO+)=(3.0+/-0.6)x10^10 (mu_L)^-1 K km/s pc^2 (where mu_L is the lensing magnification factor), corresponding to L' ratios of ~0.23-0.46 relative to CO(J=1-0). Such high line ratios would be unusual even in the respective ground-state (J=1-0) transitions, and indicate exceptional, collisionally and radiatively driven excitation conditions in the dense, star-forming molecular gas in APM08279+5255. Through an expansion of our previous modeling of the HCN line excitation in this source, we show that the high rotational line fluxes are caused by substantial infrared pumping at moderate opacities in a ~220K warm gas and dust component. This implies that standard M_dense/L' conversion factors would substantially overpredict the dense molecular gas mass M_dense. We also find a HCN J=6-5/5-4 L' ratio greater than 1 (1.36+/-0.31) - however, our models show that the excitation is likely not `super-thermal', but that the high line ratio is due to a rising optical depth between both transitions. These findings are consistent with the picture that the bulk of the gas and dust in this source is situated in a compact, nuclear starburst, where both the highly active galactic nucleus and star formation contribute to the heating.Comment: 8 pages, 5 figures, to appear in ApJ (accepted October 8, 2010

    CO(1-0) line imaging of massive star-forming disc galaxies at z=1.5-2.2

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    We present detections of the CO(J= 1-0) emission line in a sample of four massive star-forming galaxies at z~1.5-2.2 obtained with the Karl G. Jansky Very Large Array (VLA). Combining these observations with previous CO(2-1) and CO(3-2) detections of these galaxies, we study the excitation properties of the molecular gas in our sample sources. We find an average line brightness temperature ratios of R_{21}=0.70+\-0.16 and R_{31}=0.50+\-0.29, based on measurements for three and two galaxies, respectively. These results provide additional support to previous indications of sub-thermal gas excitation for the CO(3-2) line with a typically assumed line ratio R_{31}~0.5. For one of our targets, BzK-21000, we present spatially resolved CO line maps. At the resolution of 0.18'' (1.5 kpc), most of the emission is resolved out except for some clumpy structure. From this, we attempt to identify molecular gas clumps in the data cube, finding 4 possible candidates. We estimate that <40 % of the molecular gas is confined to giant clumps (~1.5 kpc in size), and thus most of the gas could be distributed in small fainter clouds or in fairly diffuse extended regions of lower brightness temperatures than our sensitivity limit

    Modal stability of inclined cables subjected to vertical support excitation

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    In this paper the out-of-plane dynamic stability of inclined cables subjected to in-plane vertical support excitation is investigated. We compute stability boundaries for the out-of-plane modes using rescaling and averaging methods. Our study focuses on the 2:1 internal resonance phenomenon between modes that occurs when the excitation frequency is twice the ļ¬rst out-of-plane natural frequency of the cable. The second in-plane mode is excited directly, while the out-of-plane modes can be excited parametrically. An analytical model is developed in order to study the stability regions in parameter space. In this model we include nonlinear coupling effects with other modes, which have thus far been omitted from previous models of parametric excitation of inclined cables. Our study reļ¬‚ects the importance of such effects. Unstable parameter regions are deļ¬ned for the selected cable conļ¬guration. The validity of the proposed stability model was tested experimentally using a small-scale cable actuator rig. A comparison between experimental and analytical results is presented in which very good agreement with model predictions was obtained. r 2008 Elsevier Ltd. All rights reserved
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