5,398 research outputs found
Have We Observed the Higgs (Imposter)?
We interpret the new particle at the Large Hadron Collider as a CP-even
scalar and investigate its electroweak quantum number. Assuming an unbroken
custodial invariance as suggested by precision electroweak measurements, only
four possibilities are allowed if the scalar decays to pairs of gauge bosons,
as exemplified by a dilaton/radion, a non-dilatonic electroweak singlet scalar,
an electroweak doublet scalar, and electroweak triplet scalars. We show that
current LHC data already strongly disfavor both the dilatonic and non-dilatonic
singlet imposters. On the other hand, a generic Higgs doublet give excellent
fits to the measured event rates of the newly observed scalar resonance, while
the Standard Model Higgs boson gives a slightly worse overall fit due to the
lack signal in the tau tau channel. The triplet imposter exhibits some tension
with the data. The global fit indicates the enhancement in the diphoton channel
could be attributed to an enhanced partial decay width, while the production
rates are consistent with the Standard Model expectations. We emphasize that
more precise measurements of the ratio of event rates in the WW over ZZ
channels, as well as the event rates in b bbar and tau tau channels, are needed
to further distinguish the Higgs doublet from the triplet imposter.Comment: 20 pages, 4 figures; v2: updated with most recent public data as of
August 7. A generic Higgs doublet now gives the best fit to data, while the
triplet imposter exhibits some tensio
Characterization of the Interaction between the Herpes Simplex Virus Type I Fc Receptor and Immunoglobulin G
Herpes simplex virus type I (HSV-1) virions and HSV-1-infected cells bind to human immunoglobulin G (hIgG) via its Fc region. A complex of two surface glycoproteins encoded by HSV-1, gE and gI, is responsible for Fc binding. We have co-expressed soluble truncated forms of gE and gI in Chinese hamster ovary cells. Soluble gE-gI complexes can be purified from transfected cell supernatants using a purification scheme that is based upon the Fc receptor function of gE-gI. Using gel filtration and analytical ultracentrifugation, we determined that soluble gE-gI is a heterodimer composed of one molecule of gE and one molecule of gI and that gE-gI heterodimers bind hIgG with a 1:1 stoichiometry. Biosensor-based studies of the binding of wild type or mutant IgG proteins to soluble gE-gI indicate that histidine 435 at the CH2-CH3 domain interface of IgG is a critical residue for IgG binding to gE-gI. We observe many similarities between the characteristics of IgG binding by gE-gI and by rheumatoid factors and bacterial Fc receptors such as Staphylococcus aureus protein A. These observations support a model for the origin of some rheumatoid factors, in which they represent anti-idiotypic antibodies directed against antibodies to bacterial and viral Fc receptors
The Nature of the UV/X-Ray Absorber in PG 2302+029
We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029.
This quasar has a rare system of ultra-high velocity (-56,000 km/s) UV
absorption lines that form in an outflow from the active nucleus (Jannuzi et
al. 2003). The Chandra data indicate that soft X-ray absorption is also
present. We perform a joint UV and X-ray analysis, using photoionization
calculations, to detemine the nature of the absorbing gas. The UV and X-ray
datasets were not obtained simultaneously. Nonetheless, our analysis suggests
that the X-ray absorption occurs at high velocities in the same general region
as the UV absorber. There are not enough constraints to rule out multi-zone
models. In fact, the distinct broad and narrow UV line profiles clearly
indicate that multiple zones are present. Our preferred estimates of the
ionization and total column density in the X-ray absorber (log U=1.6,
N_H=10^22.4 cm^-2) over predict the O VI 1032, 1038 absorption unless the X-ray
absorber is also outflowing at ~56,000 km/s, but they over predict the Ne VIII
770, 780 absorption at all velocities. If we assume that the X-ray absorbing
gas is outflowing at the same velocity of the UV-absorbing wind and that the
wind is radiatively accelerated, then the outflow must be launched at a radius
of < 10^15 cm from the central continuum source. The smallness of this radius
casts doubts on the assumption of radiative acceleration.Comment: Accepted for Publication in Ap
Raman Quantum Memory with Built-In Suppression of Four-wave Mixing Noise
Quantum memories are essential for large-scale quantum information networks.
Along with high efficiency, storage lifetime and optical bandwidth, it is
critical that the memory add negligible noise to the recalled signal. A common
source of noise in optical quantum memories is spontaneous four-wave mixing. We
develop and implement a technically simple scheme to suppress this noise
mechanism by means of quantum interference. Using this scheme with a Raman
memory in warm atomic vapour we demonstrate over an order of magnitude
improvement in noise performance. Furthermore we demonstrate a method to
quantify the remaining noise contributions and present a route to enable
further noise suppression. Our scheme opens the way to quantum demonstrations
using a broadband memory, significantly advancing the search for scalable
quantum photonic networks.Comment: 6 pages, 5 figures plus Supplementary Materia
Next-generation sequencing of advanced prostate cancer treated with androgen-deprivation therapy
<b>Background:</b>
Androgen-deprivation therapy (ADT) is standard treatment for locally advanced or metastatic prostate cancer (PCa). Many patients develop castration resistance (castration-resistant PCa [CRPC]) after approximately 2–3 yr, with a poor prognosis. The molecular mechanisms underlying CRPC progression are unclear.<p></p>
<b>Objective:</b>
To undertake quantitative tumour transcriptome profiling prior to and following ADT to identify functionally important androgen-regulated pathways or genes that may be reactivated in CRPC.<p></p>
<b>Design, setting, and participants:</b>
RNA sequencing (RNA-seq) was performed on tumour-rich, targeted prostatic biopsies from seven patients with locally advanced or metastatic PCa before and approximately 22 wk after ADT initiation. Differentially regulated genes were identified in treatment pairs and further investigated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) on cell lines and immunohistochemistry on a separate CRPC patient cohort. Functional assays were used to determine the effect of pathway modulation on cell phenotypes.<p></p>
<b>Outcome measurements and statistical analysis:</b>
We searched for gene expression changes affecting key cell signalling pathways that may be targeted as proof of principle in a CRPC in vitro cell line model.<p></p>
<b>Results and limitations:</b>
We identified ADT-regulated signalling pathways, including the Wnt/β-catenin signalling pathway, and observed overexpression of β-catenin in a subset of CRPC by immunohistochemistry. We validated 6 of 12 (50%) pathway members by qRT-PCR on LNCaP/LNCaP-AI cell RNAs, of which 4 (67%) demonstrated expression changes consistent with RNA-seq data. We show that the tankyrase inhibitor XAV939 (which promotes β-catenin degradation) reduced androgen-independent LNCaP-AI cell line growth compared with androgen-responsive LNCaP cells via an accumulation of cell proportions in the G0/G1 phase and reduction in the S and G2/M phases. Our biopsy protocol did not account for tumour heterogeneity, and pathway inhibition was limited to pharmacologic approaches.<p></p>
<b>Conclusions:</b>
RNA-seq of paired PCa samples revealed ADT-regulated signalling pathways. Proof-of-principle inhibition of the Wnt/β-catenin signalling pathway specifically delays androgen-independent PCa cell cycle progression and proliferation and warrants further investigation as a potential target for therapy for CRPC.<p></p>
Does the technique employed for skin temperature assessment alter outcomes?:a systematic review
Free to read Skin temperature is an important physiological measure that can reflect the presence of illness and injury as well as provide insight into the localised interactions between the body and the environment. The aim of this systematic review was to analyse the agreement between conductive and infrared means of assessing skin temperature which are commonly employed in in clinical, occupational, sports medicine, public health and research settings. Full-text eligibility was determined independently by two reviewers. Studies meeting the following criteria were included in the review: 1) the literature was written in English, 2) participants were human (in vivo), 3) skin surface temperature was assessed at the same site, 4) with at least two commercially available devices employed—one conductive and one infrared—and 5) had skin temperature data reported in the study. A computerised search of four electronic databases, using a combination of 21 keywords, and citation tracking was performed in January 2015. A total of 8,602 were returned. Methodology quality was assessed by 2 authors independently, using the Cochrane risk of bias tool. A total of 16 articles (n = 245) met the inclusion criteria. Devices are classified to be in agreement if they met the clinically meaningful recommendations of mean differences within ±0.5 °C and limits of agreement of ±1.0 °C. Twelve of the included studies found mean differences greater than ±0.5 °C between conductive and infrared devices. In the presence of external stimulus (e.g. exercise and/or heat) five studies foundexacerbated measurement differences between conductive and infrared devices. This is the first review that has attempted to investigate presence of any systemic bias between infrared and conductive measures by collectively evaluating the current evidence base. There was also a consistently high risk of bias across the studies, in terms of sample size, random sequence generation, allocation concealment, blinding and incomplete outcome data. This systematic review questions the suitability of using infrared cameras in stable, resting, laboratory conditions. Furthermore, both infrared cameras and thermometers in the presence of sweat and environmental heat demonstrate poor agreement when compared to conductive devices. These findings have implications for clinical, occupational, public health, sports science and research fields
Collaborative Supply Chain Decision Support And Multi-Attribute Supply Chain Scenarios
Todays Global economy is putting a premium on the ability of companies and their professional employees to rapidly evaluate a broad range of decisions in collaboration with both existing and prospective supply chain partners. This includes the development, evaluation and refinement of product designs, the evaluation of alternatives sourcing options, the evaluation of requests for bids, etc. A key difficulty in supporting the collaborative development, evaluation and refinement of alternative courses of action across different organizations lies in the complexity of the solutions involved (e.g. complex production schedules spanning multiple organizations, complex product designs or configurations involving large numbers of parts and components that are procured from a number of suppliers, etc.). Given a growing and ongoing need to revitalize the accounting curriculum and explore eclectic methods to teach accounting information systems, real challenges and opportunities exist to import this material into the accounting systems classroom.The Business Process Integration Lab at Saint Josephs University has developed a prototype environment for collaborative development, evaluation and refinement of supply chain management scenarios (e.g. requests for bids, product designs, sourcing options). The environment relies on the use of Enterprise Resource Planning software, using SAP R/3 to streamline and integrate the supply chain. Through the use of application scenarios, students are able to develop a total understanding of the power of the ERP technology tool as a decision maker and problem-solver, while enhancing their knowledge of the system in modules such as Production Planning and Customer Order Management. It is possible to support powerful workflow management functionality in the context of both interactive and highly automated decision making processes. This functionality has been operational for some three years and is coordinated by senior level graduate and undergraduate students who develop and test the scenarios and assist other students as they navigate through the R/3 system
Climate Change and Forest Fires Synergistically Drive Widespread Melt Events of the Greenland Ice Sheet
In July 2012, over 97% of the Greenland Ice Sheet experienced surface melt, the first widespread melt during the era of satellite remote sensing. Analysis of six Greenland shallow firn cores from the dry snow region confirms that the most recent prior widespread melt occurred in 1889. A firn core from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the melting events in both 1889 and 2012. We use these data to project the frequency of widespread melt into the year 2100. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, our results suggest that widespread melt events on the Greenland Ice Sheet may begin to occur almost annually by the end of century. These events are likely to alter the surface mass balance of the ice sheet, leaving the surface susceptible to further melting
Antihypertensive Drug Class and Adherence: An Electronic Monitoring Study
Background: Medication adherence is essential to optimizing blood pressure (BP) control. Prior research has demonstrated differences in pharmacy refill patterns according to antihypertensive drug class. No prior study has assessed the association between drug class and day-to-day adherence.
Methods: Between 2011 and 2014, we enrolled a convenience sample of 149 patients with persistently uncontrolled hypertension from two inner-city clinics and concurrently measured adherence of up to four antihypertensive medications using electronic pillboxes during the interval between two primary care visits. The main outcome was mean percent of days adherent to each drug. Mixed effects regression analyses were used to assess the association between drug class and adherence adjusting for age, gender, race, ethnicity, education, health insurance, coronary artery disease, heart failure, chronic kidney disease, diabetes, number of medications, days monitored, and dosing frequency.
Results: The mean age was 64 years; 72% women, 75% Hispanic, 88% prescribed ≥1 BP medication. In unadjusted analyses, adherence was lower for beta-blockers (70.9%) compared to angiotensin receptor blocking agents (75.0%, P = 0.11), diuretics (75.9%, P < 0.001), calcium channel blockers (77.6%, P < 0.001) and angiotensin-converting enzyme inhibitors (78.0%, P < 0.0001). In the adjusted analysis, only dosing frequency (P = 0.0001) but not drug class (P = 0.71) was associated with medication adherence.
Conclusions: Antihypertensive drug class was not associated with electronically measured adherence after accounting for dosing frequency amongst patients with uncontrolled hypertension. Low adherence to beta-blockers may have been due to the common practice of prescribing multiple daily dosing. Providers may consider using once daily formulations to optimize adherence and should assess adherence among all treated patients with uncontrolled hypertension.
Key words:
blood pressure drug class hypertension medication adherence
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