142 research outputs found
First Results from The GlueX Experiment
The GlueX experiment at Jefferson Lab ran with its first commissioning beam
in late 2014 and the spring of 2015. Data were collected on both plastic and
liquid hydrogen targets, and much of the detector has been commissioned. All of
the detector systems are now performing at or near design specifications and
events are being fully reconstructed, including exclusive production of
, and mesons. Linearly-polarized photons were
successfully produced through coherent bremsstrahlung and polarization transfer
to the has been observed.Comment: 8 pages, 6 figures, Invited contribution to the Hadron 2015
Conference, Newport News VA, September 201
The colonial ascidian \u3cem\u3eDidemnum\u3c/em\u3e sp. A: Current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America
Didemnum sp. A is a colonial ascidian with rapidly expanding populations on the east and west coasts of North America. The origin of Didemum sp. A is unknown. Populations were first observed on the northeast coast of the U.S. in the late 1980s and on the west coast during the 1990s. It is currently undergoing a massive population explosion and is now a dominant member of many subtidal communities on both coasts. To determine Didemnum sp. A\u27s current distribution, we conducted surveys from Maine to Virginia on the east coast and from British Columbia to southern California on the west coast of the U.S. between 1998 and 2005. In nearshore locations Didemnum sp. A currently ranges from Eastport, Maine to Shinnecock Bay, New York on the east coast. On the west coast it has been recorded from Humboldt Bay to Port San Luis in California, several sites in Puget Sound, Washington, including a heavily fouled mussel culture facility, and several sites in southwestern British Columbia on and adjacent to oyster and mussel farms. The species also occurs at deeper subtidal sites (up to 81 m) off New England, including Georges, Stellwagen and Tillies Banks. On Georges Bank numerous sites within a 230 km2 area are 50–90% covered by Didemnum sp. A; large colonies cement the pebble gravel into nearly solid mats that may smother infaunal organisms. These observations suggest that Didemnum sp. A has the potential to alter marine communities and affect economically important activities such as fishing and aquaculture
Influential factors on the levels of cation exchange capacity in sediment at Langat river.
An exploratory study was carried out at 22 sampling stations along the Langat River, Selangor in order to investigate on the vitality of cation exchange capacity (CEC) in sediment (0–5 cm). Parameters such as pH, Eh, salinity, and electrical conductivity (EC) were determined. The CEC in sediment has been calculated by the determination of Ca2+, Na+, Mg2+, and K+ using the flame atomic absorption spectrophotometer, while the organic matter content in sediment was ascertained using the loss on ignition method. The characteristic of the sediment shows that pH (3.09–7.46), salinity (0.02–10.71 ppt), EC (3.39–517 μS/cm) and Eh (−16.20–253.10 mV) were substantially high in variation. This study also revealed that exchangeable Ca2+ and Mg2+ were controlled by organic matter contents, while exchangeable Na+ and K+ were influenced by salinity. Salinity was observed to play a major part in controlling all the exchangeable cations, as it gives strong significant correlations with Na+, K+, Mg2+, CEC, and organic matter at p < 0.01. The presence of seawater, clay mineralogy, and organic matter proves that it does play an important role in determining the CEC and soon relates to the pollution magnitude in the sediment
Measurement of the J/ photoproduction cross section over the full near-threshold kinematic region
We report the total and differential cross sections for
photoproduction with the large acceptance GlueX spectrometer for photon beam
energies from the threshold at 8.2~GeV up to 11.44~GeV and over the full
kinematic range of momentum transfer squared, . Such coverage facilitates
the extrapolation of the differential cross sections to the forward ()
point beyond the physical region. The forward cross section is used by many
theoretical models and plays an important role in understanding
photoproduction and its relation to the proton interaction. These
measurements of photoproduction near threshold are also crucial inputs
to theoretical models that are used to study important aspects of the gluon
structure of the proton, such as the gluon Generalized Parton Distribution
(GPD) of the proton, the mass radius of the proton, and the trace anomaly
contribution to the proton mass. We observe possible structures in the total
cross section energy dependence and find evidence for contributions beyond
gluon exchange in the differential cross section close to threshold, both of
which are consistent with contributions from open-charm intermediate states.Comment: 15 pages 18 figure
Better Palliative Care for people with a Dementia: Summary of InterdisciplinaryWorkshop Highlighting Current Gaps and Recommendations for Future Research
Background: Dementia is the most common neurological disorder worldwide and is a life-limiting condition, but very often is not recognised as such. People with dementia, and their carers, have been shown to have palliative care needs equal in extent to those of cancer patients. However, many people with advanced dementia are not routinely being assessed to determine their palliative care needs, and it is not clear why this is so. Main body: An interdisciplinary workshop on "Palliative Care in Neurodegeneration, with a focus on Dementia", was held in Cork, Ireland, in May 2016. The key aim of this workshop was to discuss the evidence base for palliative care for people with dementia, to identify 'gaps' for clinical research, and to make recommendations for interdisciplinary research practice. To lead the discussion throughout the day a multidisciplinary panel of expert speakers were brought together, including both researchers and clinicians from across Ireland and the UK. Targeted invitations were sent to attendees ensuring all key stakeholders were present to contribute to discussions. In total, 49 experts representing 17 different academic and practice settings, attended. Key topics for discussion were pre-selected based on previously identified research priorities (e.g. James Lind Alliance) and stakeholder input. Key discussion topics included: i. Advance Care Planning for people with Dementia; ii. Personhood in End-of-life Dementia care; iii. Topics in the care of advanced dementia at home. These topics were used as a starting point, and the ethos of the workshop was that the attendees could stimulate discussion and debate in any relevant area, not just the key topics, summarised under iv. Other priorities. Conclusions: The care experienced by people with dementia and their families has the potential to be improved; palliative care frameworks may have much to offer in this endeavour. However, a solid evidence base is required to translate palliative care into practice in the context of dementia. This paper presents suggested research priorities as a starting point to build this evidence base. An interdisciplinary approach to research and priority setting is essential to develop actionable knowledge in this area
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