206 research outputs found
Recommended from our members
Towards Grid Friendly Zero Energy Buildings
High-performance buildings, such as zero-energy buildings (ZEBs), are an important step toward a reduction in greenhouse-gas emissions. Because ZEBs may exhibit large differences between demand and on-site generated electricity, residual electrical loads imposed by the building may fluctuate between positive and negative values. Furthermore, such buildings can be characterized by large temporal changes in residual load, commonly caused by clouds passing on a sunny day. Today, electricity grid operators can easily deal with a single ZEB with this behavior. But what happens if large portfolios of ZEBs have the same behavior? In this study, a highly efficient office building with a total floor area of 8,355 m2 located in Denver, Colorado, was designed and simulated using a detailed building energy modeling approach. Combining the building energy model with a photovoltaic model showed that the building reached net positive status on an annual basis. Further analysis of residual loads and strategies for their reduction revealed the limited potential of demand-side management in ZEBs and the high flexibility of batteries. Using a multiple-objective optimization approach for optimizing several simplified electric and thermal storage systems allowed the comparison of different strategies for residual load reduction. Although electrical storage may not yet be economical given today’s system costs, results show that the residual loads can be effectively managed and reduced, and at the same time, an increase in photovoltaic self-consumption can be achieved. The analysis concludes with the presentation of a multiple-objective optimal solution (Pareto front) for a battery storage model, indicating what utility incentives would be required to achieve cost-effectiveness for a range of price scenarios for battery systems.</p
Flaring Up All Over -- Radio Activity in Rapidly-Rotating Late-Type M and L Dwarfs
We present Very Large Array observations of twelve late M and L dwarfs in the
Solar neighborhood. The observed sources were chosen to cover a wide range of
physical characteristics - spectral type, rotation, age, binarity, and X-ray
and H\alpha activity - to determine the role of these properties in the
production of radio emission, and hence magnetic fields. Three of the twelve
sources, TVLM513-46546, 2MASS J0036159+182110, and BRI0021-0214, were observed
to flare and also exhibit persistent emission, indicating that magnetic
activity is not quenched at the bottom of the main sequence. The radio emission
extends to spectral type L3.5, and there is no apparent decrease in the ratio
of flaring luminosities to bolometric luminosities between M8-L3.5. Moreover,
contrary to the significant drop in persistent H\alpha activity beyond spectral
type M7, the persistent radio activity appears to steadily increase between
M3-L3.5. Similarly, the radio emission from BRI0021-0214 violates the
phenomenological relations between the radio and X-ray luminosities of
coronally active stars, hinting that radio and X-ray activity are also
uncorrelated at the bottom of the main sequence. The radio active sources that
have measured rotational velocities are rapid rotators, Vsin(i)>30 km/sec,
while the upper limits on radio activity in slowly-rotating late M dwarfs
(Vsin(i)<10 km/sec) are lower than these detections. These observations provide
tantalizing evidence that rapidly-rotating late M and L dwarfs are more likely
to be radio active. This possible correlation is puzzling given that the
observed radio emission requires sustained magnetic fields of 10-1000 G and
densities of 10^12 cm^-3, indicating that the active sources should have slowed
down considerably due to magnetic braking.Comment: Accepted to ApJ; Two new figures; Minor text revision
Hepatitis C virus dynamics among intravenous drug users suggest that an annual treatment uptake above 10% would eliminate the disease by 2030.
In Switzerland, the prevalence of hepatitis C virus (HCV) among people who inject drugs (PWID) has been decreasing owing to active harm reduction efforts and an aging population. Recent advances in HCV therapeutics may provide an opportunity to direct treatment to high-risk populations, with a goal of reducing HCV prevalence and preventing new infections. In order to guide these efforts, the current project was undertaken with the following aims: (1) to develop a simple model to estimate the number of new HCV infections using available data on PWID; (2) to examine the impact of intervention strategies (prevention and treatment) on new and total HCV infections among PWID.
A dynamic HCV transmission model was used to track HCV incidence and prevalence among active PWID according to their harm reduction status. The relative impact of treating 1, 5, 10 or 15% of HCV+ PWID with new oral direct acting antivirals was considered.
In 2015, there were an estimated 10 160 active PWID in Switzerland, more than 85% of whom were engaged in harm reduction programmes. Approximately 42% of active PWID were HCV-RNA+, with 55 new viraemic infections occurring annually. By 2030, a 60% reduction in the HCV+ PWID population would be expected. In the absence of behavioural changes, the number of secondary infections would increase under all treatment scenarios. With high level treatment, the number of secondary infections would peak and then drop, corresponding to depletion of the viral pool. In Switzerland, 5% treatment of the 2015 HCV+ PWID population per year would result in a 95% reduction in total cases by 2030, whereas ≥10% treatment would result in a >99% reduction.
Timely treatment of hepatitis C virus among people who inject drugs is necessary to reduce the prevalence and prevent new infections in Switzerland
Solar flare electron acceleration: comparing theories and observations
A popular scenario for electron acceleration in solar flares is transit-time
damping of low-frequency MHD waves excited by reconnection and its outflows.
The scenario requires several processes in sequence to yield energetic
electrons of the observed large number. Until now there was very little
evidence for this scenario, as it is even not clear where the flare energy is
released. RHESSI measurements of bremsstrahlung by non-thermal flare electrons
yield energy estimates as well as the position where the energy is deposited.
Thus quantitative measurements can be put into the frame of the global magnetic
field configuration as seen in coronal EUV line observations. We present RHESSI
observations combined with TRACE data that suggest primary energy inputs mostly
into electron acceleration and to a minor fraction into coronal heating and
primary motion. The more sensitive and lower energy X-ray observations by
RHESSI have found also small events (C class) at the time of the acceleration
of electron beams exciting meter wave Type III bursts. However, not all RHESSI
flares involve Type III radio emissions. The association of other decimeter
radio emissions, such as narrowband spikes and pulsations, with X-rays is
summarized in view of electron accelerationComment: COSPAR meeting Houston 2002, PASP proceedings, in pres
Multimodal stimulus coding by a gustatory sensory neuron in Drosophila larvae.
Accurate perception of taste information is crucial for animal survival. In adult Drosophila, gustatory receptor neurons (GRNs) perceive chemical stimuli of one specific gustatory modality associated with a stereotyped behavioural response, such as aversion or attraction. We show that GRNs of Drosophila larvae employ a surprisingly different mode of gustatory information coding. Using a novel method for calcium imaging in the larval gustatory system, we identify a multimodal GRN that responds to chemicals of different taste modalities with opposing valence, such as sweet sucrose and bitter denatonium, reliant on different sensory receptors. This multimodal neuron is essential for bitter compound avoidance, and its artificial activation is sufficient to mediate aversion. However, the neuron is also essential for the integration of taste blends. Our findings support a model for taste coding in larvae, in which distinct receptor proteins mediate different responses within the same, multimodal GRN
Nucleoprotein complexes of minute virus of mice have a distinct structure different from that of chromatin
We studied the structure of viral nucleoprotein complexes extracted from the nuclei of mouse cells infected with the immunosuppressive strain of the minute virus of mice (MVMi). Two types of complex were detected, with sedimentation coefficients of about 110 and 40S. The complexes sedimenting at 110S contained single-stranded MVMi DNA as well as a second form of viral DNA which apparently had a heat-sensitive secondary structure. The 110S peak also contained proteins which coelectrophoresed with the MVMi capsid proteins. Complexes sedimenting at 40S contained the double-stranded replicative form of MVMi DNA. These complexes sedimented faster than did the pure replicative form DNA (15S), but more slowly than cellular chromatin fragments containing DNA of the same length. They incorporated labeled deoxynucleoside triphosphate in vitro into the replicative form DNA. We investigated the structure of MVMi nucleoprotein complexes in the following ways. Nuclei of MVMi-infected cells were digested with staphylococcal nuclease, and the resulting DNA fragments were electrophoresed, transferred to nitrocellulose, and hybridized first with labeled MVMi DNA and then with cellular DNA. A nucleosomal repeat pattern was seen with the cellular DNA probe but not with the MVMi DNA probe. The DNA in MVMi nucleoprotein complexes was cross-linked with psoralen, purified, denatured, and examined with an electron microscope. Bubbles, indicating the presence of proteins, were seen in the MVMi DNA. The length of the DNA in the bubbles was 90 +/- 29 nucleotides. On the other hand, nucleosomes protected 160 base pairs from cross-linking by psoralen. The MVMi nucleoprotein complexes thus have a distinct structure which is different from that of chromatin
Chronic Hepatitis C Treatment in Patients with Drug Injection History: Findings of the INTEGRATE Prospective, Observational Study.
INTRODUCTION: People who inject drugs represent an under-treated chronic hepatitis C virus (HCV)-infected patient population. METHODS: INTEGRATE was a prospective, observational study investigating the effectiveness, safety, and adherence in routine clinical practice to telaprevir in combination with peg-interferon and ribavirin (Peg-IFN/RBV) in patients with history of injecting drug use chronically infected with genotype 1 HCV. RESULTS: A total of 46 patients were enrolled and included in the intent-to-treat (ITT) population. Among heroin and/or cocaine users (n = 37; 80%), 22% reported use in the past month; 74% (34/46) of patients were on opioid substitution therapy in the pre-treatment phase, and 43% (20/46) discontinued HCV treatment prematurely. Sustained virologic response rate was 54% (25/46) in the ITT population and 74% (25/34) in the per protocol (evaluable-for-effectiveness) population. The main reason for failure in the ITT analysis was loss to follow-up (n = 8; 17%). Adverse events occurred in 91% (42/46) of patients. Mean patient-reported adherence to study drugs was >89% at Week 4, Week 12 and end of treatment. CONCLUSION: Despite a high rate of treatment discontinuation (including loss to follow-up), self-reported adherence to treatment was good and virologic cure rates were similar to those reported in large real-world cohorts. Our findings suggest that people with a history of injecting drug use should be considered for treatment of chronic HCV infection, and highlight the need for improvements in patient support to boost retention in care and, in turn, help to prevent reinfection and transmission. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov identifier, NCT01980290. FUNDING: Janssen Pharmaceuticals
We know DAAs work, so now what?:Simplifying models of care to enhance the hepatitis C cascade
Globally, some 71 million people are chronically
infected with hepatitis C virus (HCV). Marginalised populations,
particularly people who inject drugs (PWID), have low testing,
linkage-to-care and treatment rates for HCV. Several models of
care (MoCs) and service delivery interventions have the
potential to improve outcomes across the HCV cascade of care,
but much of the relevant research was carried out when
interferon-based treatment was the standard of care. Often it
was not practical to scale up these earlier models and
interventions because the clinical care needs of patients taking
interferon-based regimens imposed too much of a financial and
human resource burden on health systems. Despite the adoption of
highly effective, all-oral direct-acting antiviral (DAA)
therapies in recent years, approaches to HCV testing and
treatment have evolved slowly and often remain rooted in earlier
paradigms. The effectiveness of DAAs allows for simpler
approaches and has encouraged countries where the drugs are
widely available to set their sights on the ambitious World
Health Organization (WHO) HCV elimination targets. Since a large
proportion of chronically HCV-infected people are not currently
accessing treatment, there is an urgent need to identify and
implement existing simplified MoCs that speak to specific
populations' needs. This article aims to: 1) review the evidence
on MoCs for HCV; and 2) distil the findings into recommendations
for how stakeholders can simplify the path taken by chronically
HCV-infected individuals from testing to cure and subsequent
care and monitoring
Survey on solar X-ray flares and associated coherent radio emissions
The radio emission during 201 X-ray selected solar flares was surveyed from
100 MHz to 4 GHz with the Phoenix-2 spectrometer of ETH Zurich. The selection
includes all RHESSI flares larger than C5.0 jointly observed from launch until
June 30, 2003. Detailed association rates of radio emission during X-ray flares
are reported. In the decimeter wavelength range, type III bursts and the
genuinely decimetric emissions (pulsations, continua, and narrowband spikes)
were found equally frequently. Both occur predominantly in the peak phase of
hard X-ray (HXR) emission, but are less in tune with HXRs than the
high-frequency continuum exceeding 4 GHz, attributed to gyrosynchrotron
radiation. In 10% of the HXR flares, an intense radiation of the above genuine
decimetric types followed in the decay phase or later. Classic meter-wave type
III bursts are associated in 33% of all HXR flares, but only in 4% they are the
exclusive radio emission. Noise storms were the only radio emission in 5% of
the HXR flares, some of them with extended duration. Despite the spatial
association (same active region), the noise storm variations are found to be
only loosely correlated in time with the X-ray flux. In a surprising 17% of the
HXR flares, no coherent radio emission was found in the extremely broad band
surveyed. The association but loose correlation between HXR and coherent radio
emission is interpreted by multiple reconnection sites connected by common
field lines.Comment: Solar Physics, in pres
- …