917 research outputs found
Peer-to-peer sharing on the Internet: An analysis of how Gnutella networks are used to distribute pornographic material
By our very nature, humans are creatures that communicate and network. Over the past several decades much of this communicating and networking has been facilitated by developments in information and communication technology. The social and economic transformations resulting from developments on the Internet have created several challenges for policymakers, lawmakers, courts and a wide range of other kinds of institutions. Some of these challenges are associated with the technologies and applications themselves. Other challenges result from content made available on the Internet and how users exchange data. Recent developments in peer-to-peer data exchange bring these two sets of challenges together
Peer-to-peer sharing on the Internet: An analysis of how Gnutella networks are used to distribute pornographic material
By our very nature, humans are creatures that communicate and network. Over the past several decades much of this communicating and networking has been facilitated by developments in information and communication technology. The social and economic transformations resulting from developments on the Internet have created several challenges for policymakers, lawmakers, courts and a wide range of other kinds of institutions. Some of these challenges are associated with the technologies and applications themselves. Other challenges result from content made available on the Internet and how users exchange data. Recent developments in peer-to-peer data exchange bring these two sets of challenges together
The Well-Being of Alcohol and Other Drug Counsellors in Australia: Strengths, Risks, and Implications
Working with alcohol and other drug (AOD) using populations in treatment services is a demanding job that has been associated with a susceptibility to stress and burnout in the workforce. The current study used an online survey methodology in Victoria, Australia, to examine staff well-being and burnout in a cohort of 228 workers in AOD specialist services in Victoria, 151 of whom hold client caseloads. Although there was a strong negative association between stress and burnout, and inverse associations with work satisfaction and well-being, the focus of the current analysis was what predicted positive well-being in workers. This was associated with four factors—lower levels of emotional exhaustion and cognitive weariness (both aspects of burnout), higher levels of opportunities for professional growth, and a greater support network in the worker’s own life with which to discuss things. Thus, positive well-being is not only linked to lower burnout, and to greater perceived development opportunities, but also to the support systems workers have access to
Modular synthesis of biologically active phosphatidic acid probes using click chemistry
Phosphatidic acid (PA) is an important signaling lipid that plays roles in a range of biological processes including both physiological and pathophysiological events. PA is one of a number of signaling lipids that can act as site-specific ligands for protein receptors in binding events that enforce membrane association and generally regulate both receptor function and subcellular localization. However, elucidation of the full scope of PA activities has proven problematic, primarily due to the lack of a consensus sequence among PA-binding receptors. Thus, experimental approaches, such as those employing lipid probes, are necessary for characterizing interactions at the molecular level. Herein, we describe an efficient modular approach to the synthesis of a range of PA probes that employs a late stage introduction of reporter groups. This strategy was exploited in the synthesis of PA probes bearing fluorescent and photoaffinity tags as well as a bifunctional probe containing both a photoaffinity moiety and an azide as a secondary handle for purification purposes. To discern the ability of these PA analogs to mimic the natural lipid in protein-binding properties, each compound was incorporated into vesicles for binding studies using a known PA receptor, the C2 domain of PKCalpha. In these studies, each compound exhibited binding properties that were comparable to those of synthetic PA, indicating their viability as probes for effectively studying the activities of PA in cellular processes
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Wafer-scale metasurface for total power absorption, local field enhancement and single molecule Raman spectroscopy
The ability to detect molecules at low concentrations is highly desired for applications that range from basic science to healthcare. Considerable interest also exists for ultrathin materials with high optical absorption, e.g. for microbolometers and thermal emitters. Metal nanostructures present opportunities to achieve both purposes. Metal nanoparticles can generate gigantic field enhancements, sufficient for the Raman spectroscopy of single molecules. Thin layers containing metal nanostructures (“metasurfaces”) can achieve near-total power absorption at visible and near-infrared wavelengths. Thus far, however, both aims (i.e. single molecule Raman and total power absorption) have only been achieved using metal nanostructures produced by techniques (high resolution lithography or colloidal synthesis) that are complex and/or difficult to implement over large areas. Here, we demonstrate a metasurface that achieves the near-perfect absorption of visible-wavelength light and enables the Raman spectroscopy of single molecules. Our metasurface is fabricated using thin film depositions, and is of unprecedented (wafer-scale) extent
Recovery identity and wellbeing: is it better to be 'recovered' or 'in recovery'?
While there has been debate about the meaning of recovery, there has been little discussion about how people characterise their own recovery experience, in particular whether people describe themselves as 'recovered' (as with a therapeutic community (TC) philosophy) or as 'in recovery' (typically those engaged in 12-step). The paper assesses differences in wellbeing as a function of recovery self-ascriptions, based on the UK Life in Recovery survey. Those who described themselves as 'recovered' or 'ex-addicts' reported better psychological health and lower identification with addicts and recovery, and showed stronger recovery functioning. There are clearly multiple pathways to recovery, and philosophy may impact on both trajectory of recovery and the social identity mechanisms underpinning change
Search for the Theta^+(1540) in lattice QCD
We report on a study of the pentaquark Theta^+(1540), using a variety of
different interpolating fields. We use Chirally Improved fermions in
combination with Jacobi smeared quark sources to improve the signal and get
reliable results even for small quark masses. The results of our quenched
calculations, which have been done on a 12^3 x 24 lattice with a lattice
spacing of a = 0.148 fm, do not provide any evidence for the existence of a
\Theta^+ with positive parity. We do observe, however, a signal compatible with
nucleon-kaon scattering state. For the negative parity the results are
inconclusive, due to the potential mixture with nucleon-kaon and N^*-kaon
scattering states.Comment: 5 pages, 2 figure
The effect of impact angle on craters formed by hypervelocity particles
The Space Power Institute (SPI) at Auburn University has conducted experiments on the effects of impact angle on crater morphology and impactor residue retention for hypervelocity impacts. Copper target plates were set at angles of 30 deg, 45 deg, 60 deg, and 75 deg from the particle flight path. For the 30 deg and 45 deg impacts, in the velocity regime greater than 8 km s(exp -1) the resultant craters are almost identical to normal incidence impacts. The only difference found was in the apparent distribution of particle residue within the crater, and further research is needed to verify this. The 60 deg and 75 deg impacts showed marked differences in crater symmetry, crater lip shape, and particle residue distribution in the same velocity regime. Impactor residue shock fractionation effects have been quantified in first-order. It is concluded that a combination of analysis techniques can yield further information on impact velocity, direction, and angle of incidence
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SLUDGE BATCH 5 SIMULANT FLOWSHEET STUDIES
The Defense Waste Processing Facility (DWPF) will transition from Sludge Batch 4 (SB4) processing to Sludge Batch 5 (SB5) processing in early fiscal year 2009. Tests were conducted using non-radioactive simulants of the expected SB5 composition to determine the impact of varying the acid stoichiometry during the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processes. The work was conducted to meet the Technical Task Request (TTR) HLW/DWPF/TTR-2007-0007, Rev. 1 and followed the guidelines of a Task Technical and Quality Assurance Plan (TT&QAP). The flowsheet studies are performed to evaluate the potential chemical processing issues, hydrogen generation rates, and process slurry rheological properties as a function of acid stoichiometry. Initial SB5 flowsheet studies were conducted to guide decisions during the sludge batch preparation process. These studies were conducted with the estimated SB5 composition at the time of the study. The composition has changed slightly since these studies were completed due to changes in the washing plan to prepare SB5 and the estimated SB4 heel mass. Nine DWPF process simulations were completed in 4-L laboratory-scale equipment using both a batch simulant (Tank 51 simulant after washing is complete) and a blend simulant (Tank 40 simulant after Tank 51 transfer is complete). Each simulant had a set of four SRAT and SME simulations at varying acid stoichiometry levels (115%, 130%, 145% and 160%). One additional run was made using blend simulant at 130% acid that included additions of the Actinide Removal Process (ARP) waste prior to acid addition and the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) waste following SRAT dewatering. There are several parameters that are noteworthy concerning SB5 sludge: (1) This is the first batch DWPF will be processing that contains sludge that has had a significant fraction of aluminum removed through aluminum dissolution. (2) The sludge is high in mercury. (3) The sludge is high in noble metals. (4) The sludge is high in U and Pu--components that are not added in sludge simulants. Two SB5 processing issues were noted during testing. First, high hydrogen generation rates were measured during experiments with both the blend and batch simulant at high acid stoichiometry. Also, the reflux time was extended due to the high mercury concentration in both the batch and blend simulant. Adding ARP will extend processing times in DWPF. The ARP caustic boil took approximately six hours. The boiling time during the experiment with added MCU was 14 hours at the maximum DWPF steam flux rate. This is comparable to the DWPF processing time for dewatering plus reflux without MCU at a 5000 lbs/hr boil-up rate, but would require significantly more time at boiling at 2000-2500 lbs/hr boil-up rate. The addition of ARP and MCU did not cause any other processing issues, since foaming, rheology and hydrogen generation were less of an issue while processing with ARP/MCU
Examining the association of life course neurocognitive ability with real-world functioning in schizophrenia-spectrum disorders
There is considerable variability in neurocognitive functioning within schizophrenia-spectrum disorders, and neurocognitive performance ranges from severe global impairment to normative performance. Few investigations of neurocognitive clusters have considered the degree to which deterioration relative to premorbid neurocognitive abilities is related to key illness characteristics. Moreover, while neurocognition and community functioning are strongly related, understanding of the sources of variability in the association between these two domains is also limited; it is unknown what proportion of participants would over-perform or under-perform the level of functioning expected based on current neurocognitive performance vs. lifelong attainment. This study examined data from 954 outpatients with schizophrenia-spectrum disorders across three previous studies. Neurocognition, community functioning, and symptoms were assessed. Neurocognitive subgroups were created based on current neurocognition, estimated premorbid IQ, and degree of deterioration from premorbid using z-score cut-offs; functional subgroups were created with cluster analysis based on the Specific Level of Functioning Scale and current neurocognition. The sample was neurocognitively heterogeneous; 65% displayed current neurocognitive impairment and 84% experienced some level of deterioration. Thirty percent of our sample was relatively higher functioning despite significant neurocognitive impairment. Individuals with better community functioning, regardless of neurocognitive performance, had lower symptom severity compared to those with worse functioning. These results highlight the variability in neurocognition and its role in functioning. Understanding individual differences in neurocognitive and functional profiles and the interaction between prior and current cognitive functioning can guide individualized treatment and selection of participants for clinical treatment studies
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