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Although Ti3C2T x has been widely studied in applications such as electrical storage devices, there are very few reports about the field emission properties of Ti3C2T x . In this work, 2-D Ti3C2T x MXene was fabricated by simple etching Al layer from Ti3AlC2 in hydrofluoric acid (HF) at room temperature and employed as a cold cathode for field emission devices. The device presents a high field emission performance with a low turn-on field of 2.7 V/ $\mu \text{m}$ and excellent stability, much lower than the reported value of the former work (around 5 V/ $\mu \text{m}$ ), its relative 1-D TiC nanowires (7.1 V/ $\mu \text{m}$ ), and most of other 2-D cathode materials, such as MoS2 and graphene, which is found due to its unique accordion structure with evenly distributed sharp edges and enlarged layer spacing reducing the field screening effect. The results confirmed by numerical simulation demonstrate that the local electric intensity at sharp edges indeed significantly higher than that of elsewhere. In other words, more sharp edges owning to the increased interlayer spacing exposed, which can considerably boost field emission performance. Based on experimental data and simulation analysis, the edge effect was found to correspond well with other former reports. Hence, 2-D MXene can be a promising candidate for vacuum electronic applications other than energy storage and conversion devices.

During May 19-September 28, 2019,* low levels of influenza activity were reported in the United States, with cocirculation of influenza A and influenza B viruses. In the Southern Hemisphere seasonal influenza viruses circulated widely, with influenza A(H3) predominating in many regions; however, influenza A(H1N1)pdm09 and influenza B viruses were predominant in some countries. In late September, the World Health Organization (WHO) recommended components for the 2020 Southern Hemisphere influenza vaccine and included an update to the A(H3N2) and B/Victoria-lineage components. Annual influenza vaccination is the best means for preventing influenza illness and its complications, and vaccination before influenza activity increases is optimal. Health care providers should recommend vaccination for all persons aged ≥6 months who do not have contraindications to vaccination (1).

CDC collects, compiles, and analyzes data on influenza activity and viruses in the United States. During September 30, 2018-February 2, 2019,* influenza activity† in the United States was low during October and November, increased in late December, and remained elevated through early February. As of February 2, 2019, this has been a low-severity influenza season (1), with a lower percentage of outpatient visits for influenza-like illness (ILI), lower rates of hospitalization, and fewer deaths attributed to pneumonia and influenza, compared with recent seasons. Influenza-associated hospitalization rates among children are similar to those observed in influenza A(H1N1)pdm09 predominant seasons; 28 influenza-associated pediatric deaths occurring during the 2018-19 season have been reported to CDC. Whereas influenza A(H1N1)pdm09 viruses predominated in most areas of the country, influenza A(H3N2) viruses have predominated in the southeastern United States, and in recent weeks accounted for a growing proportion of influenza viruses detected in several other regions. Small numbers of influenza B viruses (

During May 20-October 13, 2018,* low levels of influenza activity were reported in the United States, with a mix of influenza A and B viruses circulating. Seasonal influenza activity in the Southern Hemisphere was low overall, with influenza A(H1N1)pdm09 predominating in many regions. Antigenic testing of available influenza A and B viruses indicated that no significant antigenic drift in circulating viruses had emerged. In late September, the components for the 2019 Southern Hemisphere influenza vaccine were selected and included an incremental update to the A(H3N2) vaccine virus used in egg-based vaccine manufacturing; no change was recommended for the A(H3N2) component of cell-manufactured or recombinant influenza vaccines. Annual influenza vaccination is the best method for preventing influenza illness and its complications, and all persons aged ≥6 months who do not have contraindications should receive influenza vaccine, preferably before the onset of influenza circulation in their community, which often begins in October and peaks during December-February. Health care providers should offer vaccination by the end of October and should continue to recommend and administer influenza vaccine to previously unvaccinated patients throughout the 2018-19 influenza season (1). In addition, during May 20-October 13, a small number of nonhuman influenza "variant" virus infections† were reported in the United States; most were associated with exposure to swine. Although limited human-to-human transmission might have occurred in one instance, no ongoing community transmission was identified. Vulnerable populations, especially young children and other persons at high risk for serious influenza complications, should avoid swine barns at agricultural fairs, or close contact with swine.§.

Logging is widely used to provide atomicity and durability for transactions in database management systems (DBMSs). For decades, the traditional logging protocol for disk-oriented database storage engines focuses on making a trade-off between data persistence and performance loss due to the large performance gap and access granularity mismatch between dynamic random-access memory (DRAM) and disks. With the development of persistent memory (PM) especially the release of the commercial Optane DC Persistent Memory Module (Optane DCPMM), a new class of storage engine which employs PM as its primary storage has emerged. The disk-based logging protocol is not suitable for these PM-aware storage engines, since PM provides data persistence and has low-latency comparable to DRAM. In this paper, we design and implement an efficient logging protocol for PM-aware storage engines: Bucket Logging (BKL). BKL uses the per-transaction log structure (i.e., bucket) to store logs internally and ensures efficient writing of metadata and logs. Benefit from multi version concurrency control, BKL only records small fixed-size log entries to implement fast logging and crash recovery. Moreover, we optimize our design based on our basic performance evaluation of Optane DCPMM. We implement a micro storage engine in MariaDB and using YCSB to evaluate BKL's performance on Optane DCPMM. The results show that the storage engine with BKL has 1.5 × −7.1 × higher throughput compared to InnoDB under write-heavy workloads. Compared with other logging protocol, BKL achieves higher throughput and better scalability and reduces the system performance recovery time by 1.4 ×−11.8 ×.

The Amazon Basin is experiencing climate change, altered hydrological cycles, and forest loss. The processes causing increased fires are complex, and therefore cannot be attributed to climate change or human-induced deforestation alone. Here, we show why the Amazon fires must be understood across spatial scales within the regional coupled system.

Water loss reduction is important in sustainable water resource management. As one of the main water loss control methods, early detection of hydraulic accidents in district metering areas ...

Our planet is undergoing one of the most rapid climate changes in Earth’s history. The current change is particularly significant because it is most likely a consequence of human activities since the 19th century. The Digital Earth platform, which includes Earth-orbiting satellites, ground-based observations, and other technologies for collecting, analyzing and visualizing data, has enabled scientists to see our climate and its impacts at regional and global scales. The Digital Earth platform offers valuable information on the atmosphere, biosphere, hydrosphere and cryosphere to understand Earth’s past and present, and it supports Earth system models for climate prediction and projection. This chapter gives an overview of the advances in climate change studies based on Digital Earth and provides case studies that utilize Digital Earth in climate change research, such as in the observation of sensitive factors for climate change, global environmental change information and simulation systems, and synchronous satellite-aerial-ground observation experiments, which provide extremely large and abundant datasets. The mapping of climate extremes and impacts improves preparedness for climate change-related risks and provides robust evidence to support climate risk management and climate change adaptation for the public, decision makers, investors, and vulnerable communities. However, Digital Earth faces the challenges of multisource data coordination and integration, requiring international partnerships between governments and other organizations to advance open data policies and practices.

This article describes how in traditional edge detection it is prone to defects such as fuzzy positioning, and noise influence. This article proposes a type of edge detection algorithm which combines lifting wavelet transform and adaptive mathematical morphology, which makes a lifting wavelet to analyze the wood cell image. Then, the high-frequency part is detected by using the algorithm fusing the wavelet packet and the rapid-combining multi-scale wavelet, which controls noise effectively; while for the low frequency part is detected with modified adaptive mathematical morphology, to locate the exact details. The final result will processes the edge of the image using “algebra” algorithm fusion. The example for a wood cell image which illustrates the algorithm is to detect the cell boundary relatively clearly, and effectively suppress the noise.

The United States 2017-18 influenza season (October 1, 2017-May 19, 2018) was a high severity season with high levels of outpatient clinic and emergency department visits for influenza-like illness (ILI), high influenza-related hospitalization rates, and elevated and geographically widespread influenza activity across the country for an extended period. Nationally, ILI activity began increasing in November, reaching an extended period of high activity during January-February, and remaining elevated through March. Influenza A(H3N2) viruses predominated through February and were predominant overall for the season; influenza B viruses predominated from March onward. This report summarizes U.S. influenza activity* during October 1, 2017-May 19, 2018.†.

Influenza activity in the United States was low during October 2017, but has been increasing since the beginning of November. Influenza A viruses have been most commonly identified, with influenza A(H3N2) viruses predominating. Several influenza activity indicators were higher than is typically seen for this time of year. The majority of influenza viruses characterized during this period were genetically or antigenically similar to the 2017-18 Northern Hemisphere cell-grown vaccine reference viruses. These data indicate that currently circulating viruses have not undergone significant antigenic drift; however, circulating A(H3N2) viruses are antigenically less similar to egg-grown A(H3N2) viruses used for producing the majority of influenza vaccines in the United States. It is difficult to predict which influenza viruses will predominate in the 2017-18 influenza season; however, in recent past seasons in which A(H3N2) viruses predominated, hospitalizations and deaths were more common, and the effectiveness of the vaccine was lower. Annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. Multiple influenza vaccines are approved and recommended for use during the 2017-18 season, and vaccination should continue to be offered as long as influenza viruses are circulating and unexpired vaccine is available. This report summarizes U.S. influenza activity* during October 1-November 25, 2017 (surveillance weeks 40-47).†.

Urban green spaces (UGS) can help to moderate the urban heat island effect and thus thermal comfort through the impact of landscape design parameters with regard to the land cover features. The current work investigates the thermal comfort modification potential of a long belt-shaped park (around 9 km) in Beijing and the effects of its landscape parameters using numerical simulation. Holistic spatial and temporal distribution scenarios of thermal comfort of the park are obtained in terms of physiological equivalent temperature (PET). The UGS covered regions generally exhibit better thermal comfort level, but deteriorating phenomenon is also found at some uncovered sites in the park due to the solar-radiation and enhanced reflection effect. At 14:00 h, the mean reduced PET (△PETm) by UGS are around 2 °C with the maximum and minimum value being 15.6 °C and −8.4 °C, respectively. Regression analyses show that the most significant influential factor on the moderation of thermal comfort is the higher trees, while the hardened ground exhibits a negative effect. The outcome of the current work provides detailed knowledge on the benefits of UGS and gives suggestions for urban landscape planners and policy makers to improve urban thermal comfort.

Urban green spaces have been demonstrated to bring environmental benefits from the distinctive effects of various landscape parameters. The current study investigates the cooling and energy saving effect of landscape parameters in an urban park of Beijing during a hot summer. Continuous in-site microclimate data of individual parameters including grass, water body, tree and artificial shading device (including Chinese style pavilion) and certain combination like grass + tree, water body + tree and shading device + tree were collected. Thermal perception of people caused by each parameter was studied according to both the measured data and thermal sensation votes from questionnaire survey. Based on those field measurements, the heat reduced and thus the energy saved by each parameter are estimated. The results indicate that manmade shading device performs the best cooling and energy saving effect among those individual parameters, and shading device + tree shows the optimal effect among all the chosen ones. The calculated objective thermal discomfort indexes show certain deviation from the real responses of the visitors. The heat reduced by each landscape parameter during a measuring period of 6 h from 10:00 to 16:00 h in the current case sequence to an order of water body (11,298 J m −3 ) −3 ) −3 ) −3 ) −3 ) −3 ) −3 ), while the electric energy saving potential with regard to air conditioning follows the same order with the values of 9.108 × 10 −3 , 2.129 × 10 −2 , 6.21 × 10 −2 , 6.678 × 10 −2 , 7.338 × 10 −2 , 7.947 × 10 −2 and 8.229 × 10 −2 kWh m −3 respectively. The outcomes of this work provide practical information on the benefits of the urban green spaces for the decision makers and landscape designers.

During the 2016-17 influenza season (October 2, 2016-May 20, 2017) in the United States, influenza activity* was moderate. Activity remained low through November, increased during December, and peaked in February nationally, although there were regional differences in the timing of influenza activity. Influenza A(H3N2) viruses predominated through mid-March and were predominant overall for the season, but influenza B viruses were most commonly reported from late March through May. This report summarizes influenza activity in the United States during October 2, 2016-May 20, 2017† and updates the previous summary (1).

In this paper, the dynamic response characteristics of a common double shear lap joint structure with viscoelastic layer are investigated. Firstly, an analytical model is established in shear vibration based on phenomenological model. The fourth order Runge-Kutta method is employed to calculate the harmonic response, where the effect of Coulomb friction and excitation levels on system are presented. Secondly, a new nonlinear finite element model for the bolted joint structure with viscoelastic layer is developed. The simulation results show good agreement with the corresponding experimental results. Finally, the proposed harmonic excitation experiments with laser vibrometer in tangential direction are carried out to investigate the nonlinear behaviors of system, as well as the influence of bolt preload and viscoelastic material on dynamic characteristics of the bolted joint beam. The results show that the viscoelastic layer help reduce vibration at certain extent, especially in the high frequency region of vibration, and some peak frequencies of system can be changed through the viscoelastic layer.

Epidemiological studies suggest that humans who receive repeated annual immunization with influenza vaccine are less well protected against influenza than those who receive vaccine in the current season only. To better understand potential mechanisms underlying these observations, we vaccinated influenza-naive ferrets either twice, 10 months apart (repeated vaccination group; RV), or once (current season only group; CS), using a prime-boost regimen, and then challenged the ferrets with A/Hong Kong/4801/2014(H3N2). Ferrets that received either vaccine regimen were protected against influenza disease and infection relative to naive unvaccinated ferrets, but the RV group shed more virus, especially at the peak of virus shedding 2 days post infection (p, Influenza: Repeat vaccination impairs protection Epidemiological evidence suggests that influenza vaccination in prior years can reduce the efficacy of influenza vaccination compared to vaccine given in the current season alone. Ian A. York and colleagues of the Centers for Disease Control and Prevention, USA investigate this phenomenon using the human relevant ferret model of influenza infection. Ferrets undergoing repeat vaccination — twice 10 months apart — show quantitatively similar antibody and cell-mediated immune responses as those given a single current-season vaccination. However, qualitatively the responses elicited by the current season vaccine alone are superior — with animals showing less dramatic loss of body weight, milder fever, reduced virus shedding and quicker recovery of lymphocyte numbers. Although less protective than current-season vaccination alone, repeated vaccination offers better protection than mock vaccination.

Influenza activity* in the United States during the 2018-19 season (September 30, 2018-May 18, 2019) was of moderate severity (1). Nationally, influenza-like illness (ILI)† activity began increasing in November, peaked during mid-February, and returned to below baseline in mid-April; the season lasted 21 weeks,§ making it the longest season in 10 years. Illness attributed to influenza A viruses predominated, with very little influenza B activity. Two waves of influenza A were notable during this extended season: influenza A(H1N1)pdm09 viruses from October 2018 to mid-February 2019 and influenza A(H3N2) viruses from February through May 2019. Compared with the 2017-18 influenza season, rates of hospitalization this season were lower for adults, but were similar for children. Although influenza activity is currently below surveillance baselines, testing for seasonal influenza viruses and monitoring for novel influenza A virus infections should continue year-round. Receiving a seasonal influenza vaccine each year remains the best way to protect against seasonal influenza and its potentially severe consequences.

The emergence of severe acute respiratory syndrome (SARS) underscored the importance of influenza detection and response in China. From 2004, the Chinese National Influenza Center (CNIC) and the United States Centers for Disease Control and Prevention (USCDC) initiated Cooperative Agreements to build capacity in influenza surveillance in China. From 2004 to 2014, CNIC and USCDC collaborated on the following activities: 1) developing human technical expertise in virology and epidemiology in China; 2) developing a comprehensive influenza surveillance system by enhancing influenza-like illness (ILI) reporting and virological characterization; 3) strengthening analysis, utilization and dissemination of surveillance data; and 4) improving early response to influenza viruses with pandemic potential. Since 2004, CNIC expanded its national influenza surveillance and response system which, as of 2014, included 408 laboratories and 554 sentinel hospitals. With support from USCDC, more than 2500 public health staff from China received virology and epidemiology training, enabling > 98% network laboratories to establish virus isolation and/or nucleic acid detection techniques. CNIC established viral drug resistance surveillance and platforms for gene sequencing, reverse genetics, serologic detection, and vaccine strains development. CNIC also built a bioinformatics platform to strengthen data analysis and utilization, publishing weekly on-line influenza surveillance reports in English and Chinese. The surveillance system collects 200,000–400,000 specimens and tests more than 20,000 influenza viruses annually, which provides valuable information for World Health Organization (WHO) influenza vaccine strain recommendations. In 2010, CNIC became the sixth WHO Collaborating Centre for Influenza. CNIC has strengthened virus and data sharing, and has provided training and reagents for other countries to improve global capacity for influenza control and prevention. The collaboration’s successes were built upon shared mission and values, emphasis on long-term capacity development and sustainability, and leadership commitment.

Influenza activity in the United States was low during October 2018, and, although it increased slowly during November, activity remains low across most of the country.* During the week ending December 1, 2018, the percentage of outpatient visits for influenza-like illness† (ILI) was equal to the national baseline§ (Figure) and was at or slightly above the region-specific baseline in four of the 10 U.S. Department of Health and Human Services regions¶ (Regions 4 and 7–9). The majority of jurisdictions experienced minimal or low ILI activity since September 30; however, two experienced moderate ILI activity, and two experienced high ILI activity** during the week ending December 1. The percentage of deaths attributed to pneumonia and influenza remains below the epidemic threshold,†† and the rate of influenza-associated hospitalizations remains low. Five laboratory-confirmed, influenza-associated pediatric deaths occurring since September 30 have been reported to CDC. During the week ending December 1, the majority of jurisdictions (40 states, the District of Columbia, Puerto Rico, and U.S. Virgin Islands) reported sporadic or local geographic spread of influenza activity, nine states reported regional activity, and one state reported widespread activity.§§ Open in a separate window FIGURE Percentage of visits for influenza-like illness (ILI) — U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet), weekly national summary, 2018–2019* and selected previous seasons * As of December 7, 2018.

Indoor localization systems based on Wi-Fi signal strength fingerprinting techniques are widely used in office buildings. However, a general problem of these systems pertains to Wi-Fi signal degradation due to the environmental factors. And also, these systems cannot be used in the environments not covered with Wi-Fi signals or the environments with only a single Wi-Fi access point. In this paper, a new indoor location fingerprinting system using both FM radio and Digital Television Terrestrial Multimedia Broadcasting (DTMB) signals is proposed. First, the indoor location fingerprinting using FM radio and DTMB signals is theoretically analyzed to confirm its feasibility. Then, a specially designed combined strength fingerprinting location algorithm is proposed for the location system, which is achieved on the USRP2 platform. Finally, the system is tested in a typical indoor environment. The theoretical analysis and the tests show that the indoor location fingerprinting system using FM radio and DTMB signals has a similar localization accuracy to the Wi-Fi signal strength fingerprinting location system, while it has a wider coverage area, a lower maintenance cost, and more stable signal strength, which makes it a practical indoor positioning method.

Background Monitoring influenza virus susceptibility to neuraminidase (NA) inhibitors (NAIs) is vital for detecting drug-resistant variants, and is primarily assessed using NA inhibition (NI) assays, supplemented by NA sequence analysis. However, differences in NI testing methodologies between surveillance laboratories results in variability of 50% inhibitory concentration (IC50) values, which impacts data sharing, reporting and interpretation. In 2011, the Centers for Disease Control and Prevention (CDC), in collaboration with the Association for Public Health Laboratories (APHL) spearheaded efforts to standardize fluorescence-based NI assay testing in the United States (U.S.), with the goal of achieving consistency of IC50 data. Methods For the standardization process, three participating state public health laboratories (PHLs), designated as National Surveillance Reference Centers for Influenza (NSRC-Is), assessed the NAI susceptibility of the 2011–12 CDC reference virus panel using stepwise procedures, with support from the CDC reference laboratory. Next, the NSRC-Is assessed the NAI susceptibility of season 2011–12 U.S. influenza surveillance isolates (n = 940), with a large subset (n = 742) tested in parallel by CDC. Subsequently, U.S. influenza surveillance isolates (n = 9629) circulating during the next three influenza seasons (2012–15), were independently tested by the three NSRC-Is (n = 7331) and CDC (n = 2298). Results The NI assay IC50s generated by respective NSRC-Is using viruses and drugs prepared by CDC were similar to those obtained with viruses and drugs prepared in-house, and were uniform between laboratories. IC50s for U.S. surveillance isolates tested during four consecutive influenza seasons (2011–15) were consistent from season to season, within and between laboratories. Conclusion These results show that the NI assay is robust enough to be standardized, marking the first time IC50 data have been normalized across multiple laboratories, and used for U.S. national NAI susceptibility surveillance.

The dynamic response of crucial components often depends upon the dynamic behavior of bolted connections. As is usually the case, the accurate modeling of structures with many mechanical joints remains a challenge work. The nonlinear behavior included in assembled structures strongly depends on the interface properties. In this paper, an analytical model of the simple bolted joint beam in tangential direction is first proposed for transient excitation, based on phenomenological model. The fourth-order Runge-Kutta method is employed to calculate the transient response, where the dynamic response of the nonlinear stiffness on system is also investigated. The simulation results show that natural frequency has a certain dependence on cubic stiffness term and cubic stiffness is more suitable for modeling of nonlinear system of a wider frequency range. Thereby, a series Iwan model containing cubic stiffness term is established to describe nonlinear behaviors of bolted joint beams in shear vibration. The amplitude-frequency curves show that the influence of interaction between nonlinear stiffness and damping mechanism on dynamic response characteristics is more obvious. Finally, a new type of nonlinear model is applied into finite element analysis. The results of proposed transient excitation experiment are discussed qualitatively, indicating that nonlinear effects observed agree with the numerical simulation results.

Risk of cross-connection is becoming higher due to greater construction of potable-reclaimed water dual distribution systems. Cross-connection events can result in serious health concerns and reduce public confidence in reclaimed water. Thus, reliable, cost-effective and real-time online detection methods for early warning are required. The current study carried out pilot-scale experiments to simulate potable-reclaimed water pipe cross-connection events for different mixing ratios (from 30% to 1%) using machine learning methods based on multiple conventional water quality parameters. The parameters included residual chlorine, pH, turbidity, temperature, conductivity, oxidation-reduction potential and chemical oxygen demand. The results showed that correlated variation occurred among water quality parameters at the time of the cross-connection event. A single parameter-based method can be effective at high mixing ratios, but not at low mixing ratios. The direct supporting vector machine (SVM)-based method managed to overcome this drawback, but coped poorly with abnormal readings of water parameter sensors. In that respect, a Pearson correlation coefficient (PCC)-SVM-based method was developed. It provided not only high detection performance under normal conditions, but also remained reliable when abnormal readings occurred. The detection accuracy and true positive rate of this method was still over 88%, and the false positive rate was below 12%, given a sudden variation of an individual water quality parameter. The receiver operating characteristic curves further confirmed the promising practical applicability of this PCC-SVM-based method for early detection of cross-connection events.

From October through mid-December 2015, influenza activity remained low in most regions of the United States. Activity began to increase in late December 2015 and continued to increase slowly through early February 2016. Influenza A viruses have been most frequently identified, with influenza A (H3N2) viruses predominating during October until early December, and influenza A (H1N1)pdm09 viruses predominating from mid-December until early February. Most of the influenza viruses characterized during that time are antigenically similar to vaccine virus strains recommended for inclusion in the 2015-16 Northern Hemisphere vaccines. This report summarizes U.S. influenza activity* during October 4, 2015-February 6, 2016, and updates the previous summary (1).

During May 21-September 23, 2017,* the United States experienced low-level seasonal influenza virus activity; however, beginning in early September, CDC received reports of a small number of localized influenza outbreaks caused by influenza A(H3N2) viruses. In addition to influenza A(H3N2) viruses, influenza A(H1N1)pdm09 and influenza B viruses were detected during May-September worldwide and in the United States. Influenza B viruses predominated in the United States from late May through late June, and influenza A viruses predominated beginning in early July. The majority of the influenza viruses collected and received from the United States and other countries during that time have been characterized genetically or antigenically as being similar to the 2017 Southern Hemisphere and 2017-18 Northern Hemisphere cell-grown vaccine reference viruses; however, a smaller proportion of the circulating A(H3N2) viruses showed similarity to the egg-grown A(H3N2) vaccine reference virus which represents the A(H3N2) viruses used for the majority of vaccine production in the United States. Also, during May 21-September 23, 2017, CDC confirmed a total of 33 influenza variant virus

Background Influenza outbreaks can occur among passengers and crews during the Alaska summertime cruise season. Ill travellers represent a potential source for introduction of novel or antigenically drifted influenza virus strains to the United States. From May to September 2013-2015, the Alaska Division of Public Health, the Centers for Disease Control and Prevention (CDC), and two cruise lines implemented a laboratory-based public health surveillance project to detect influenza and other respiratory viruses among ill crew members and passengers on select cruise ships in Alaska. Methods Cruise ship medical staff collected 2-3 nasopharyngeal swab specimens per week from passengers and crew members presenting to the ship infirmary with acute respiratory illness (ARI). Specimens were tested for respiratory viruses at the Alaska State Virology Laboratory (ASVL); a subset of specimens positive for influenza virus were sent to CDC for further antigenic characterization. Results Of 410 nasopharyngeal specimens, 83% tested positive for at least one respiratory virus; 71% tested positive for influenza A or B virus. Antigenic characterization of pilot project specimens identified strains matching predominant circulating seasonal influenza virus strains, which were included in the northern or southern hemisphere influenza vaccines during those years. Results were relatively consistent across age groups, recent travel history, and influenza vaccination status. Onset dates of illness relative to date of boarding differed between northbound (occurring later in the voyage) and southbound (occurring within the first days of the voyage) cruises. Conclusions The high yield of positive results indicated that influenza was common among passengers and crews sampled with ARI. This finding reinforces the need to bolster influenza prevention and control activities on cruise ships. Laboratory-based influenza surveillance on cruise ships may augment inland influenza surveillance and inform control activities. However, these benefits should be weighed against the costs and operational limitations of instituting laboratory-based surveillance programs on ships.

Increasing atmospheric methane (CH4) concentrations have contributed to approximately 20% of anthropogenic climate change. Despite the importance of CH4 as a greenhouse gas, its atmospheric growth rate and dynamics over the past two decades, which include a stabilization period (1999–2006), followed by renewed growth starting in 2007, remain poorly understood. We provide an updated estimate of CH4 emissions from wetlands, the largest natural global CH4 source, for 2000–2012 using an ensemble of biogeochemical models constrained with remote sensing surface inundation and inventory-based wetland area data. Between 2000–2012, boreal wetland CH4 emissions increased by 1.2 Tg yr−1 (−0.2–3.5 Tg yr−1), tropical emissions decreased by 0.9 Tg yr−1 (−3.2−1.1 Tg yr−1), yet globally, emissions remained unchanged at 184 ± 22 Tg yr−1. Changing air temperature was responsible for increasing high-latitude emissions whereas declines in low-latitude wetland area decreased tropical emissions; both dynamics are consistent with features of predicted centennial-scale climate change impacts on wetland CH4 emissions. Despite uncertainties in wetland area mapping, our study shows that global wetland CH4 emissions have not contributed significantly to the period of renewed atmospheric CH4 growth, and is consistent with findings from studies that indicate some combination of increasing fossil fuel and agriculture-related CH4 emissions, and a decrease in the atmospheric oxidative sink.

In February the World Health Organisation (WHO) recommends influenza viruses to be included in influenza vaccines for the forthcoming winter in the Northern Hemisphere. These recommendations are based on data collected by National Influenza Centres (NICs) through the WHO Global Influenza Surveillance and Response System (GISRS) and a more detailed analysis of representative and potential antigenically variant influenza viruses from the WHO Collaborating Centres for Influenza (WHO CCs) and Essential Regulatory Laboratories (ERLs). This article provides a detailed summary of the antigenic and genetic properties of viruses and additional background data used by WHO experts during development of the recommendations of the 2013–2014 Northern Hemisphere influenza vaccine composition.

This report summarizes U.S. influenza activity* during October 2-December 17, 2016.† Influenza activity in the United States remained low in October and has been slowly increasing since November. Influenza A viruses were identified most frequently, with influenza A (H3N2) viruses predominating. Most influenza viruses characterized during this period were genetically or antigenically similar to the reference viruses representing vaccine components recommended for production in the 2016-17 Northern Hemisphere influenza vaccines.

The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (similar to biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 TgCH(4) yr(-1), range 540-568. About 60% of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 TgCH(4) yr(-1), range 596-884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (similar to 64% of the global budget, amp;lt;30 degrees N) as compared to mid (similar to 32 %, 30-60 degrees N) and high northern latitudes (similar to 4 %, 60-90 degrees N). Top-down inversions consistently infer lower emissions in China (similar to 58 TgCH(4) yr(-1), range 51-72, -14 %) and higher emissions in Africa (86 TgCH(4) yr(-1), range 73-108, + 19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models. The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30-40% on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1) and the Global Carbon Project. Funding Agencies|Swiss National Science Foundation; NASA [NNX14AF93G, NNX14AO73G]; National Environmental Science Program - Earth Systems and Climate Change Hub; European Commission [283576, 633080]; ESA Climate Change Initiative Greenhouse Gases Phase 2 project; US Department of Energy, BER [DE-AC02-05CH11231]; FAO member countries; Environment Research and Technology Development Fund of the Ministry of the Environment, Japan [2-1502]; ERC [322998]; NERC [NE/J00748X/1]; Swedish Research Council VR; Research Council of Norway [244074]; NSF [1243232, 1243220]; National Science and Engineering Research Council of Canada (NSERC); Chinas QianRen Program; CSIRO Australia; Australian Bureau of Meteorology; Australian Institute of Marine Science; Australian Antarctic Division; NOAA USA; Meteorological Service of Canada; National Aeronautic and Space Administration (NASA) [NAG5-12669, NNX07AE89G, NNX11AF17G, NNX07AE87G, NNX07AF09G, NNX11AF15G, NNX11AF16G]; Department of Energy and Climate Change (DECC, UK) [GA01081]; Commonwealth Scientific and Industrial Research Organization (CSIRO Australia); Bureau of Meteorology (Australia); Joint DECC/Defra Met Office Hadley Centre Climate Programme [GA01101]

In February and September each year the World Health Organisation (WHO) recommends influenza viruses to be included in influenza vaccines for the forthcoming winters in the Northern and Southern Hemispheres respectively. These recommendations are based on data collected by National Influenza Centres (NIC) through the Global Influenza Surveillance and Response System (GISRS) and a more detailed analysis of representative and potential antigenically variant influenza viruses from the WHO Collaborating Centres for Influenza (WHO CCs) and Essential Regulatory Laboratories (ERLs). This article provides a detailed summary of the antigenic and genetic properties of viruses and additional background data used by WHO experts during development of the recommendations for the 2012 Southern Hemisphere influenza vaccine composition.

OBJECTIVE: To estimate the incidence of influenza-virus-associated severe pneumonia among Salvadorian children aged < 5 years. METHODS: Data on children aged < 5 years admitted with severe pneumonia to a sentinel hospital in the western region were collected weekly. Nasal and oropharyngeal swab specimens were collected from a convenience sample of case patients for respiratory virus testing. A health-care utilization survey was conducted in the hospital catchment area to determine the proportion of residents who sought care at the hospital. The incidence of influenza-virus-associated severe pneumonia among all Salvadorian children aged < 5 years was estimated from surveillance and census data, with adjustment for health-care utilization. Influenza virus strains were characterized by the United States Centers for Disease Control and Prevention to determine their correspondence with northern and southern hemisphere influenza vaccine formulations. FINDINGS: Physicians identified 2554 cases of severe pneumonia. Samples from 608 cases were tested for respiratory viruses and 37 (6%) were positive for influenza virus. The estimated incidence of influenza-virus-associated severe pneumonia was 3.2 cases per 1000 person-years (95% confidence interval, CI: 2.8-3.7) overall, 1.5 cases per 1000 person-years (95% CI: 1.0-2.0) during 2008, 7.6 cases per 1000 person-years (95% CI: 6.5-8.9) during 2009 and 0.6 cases per 1000 person-years (95% CI: 0.3-1.0) during 2010. Northern and southern hemisphere vaccine formulations matched influenza virus strains isolated during 2008 and 2010. CONCLUSION: Influenza-virus-associated severe pneumonia occurred frequently among young Salvadorian children during 2008-2010. Antigens in northern and southern hemisphere influenza vaccine formulations corresponded to circulating strains.

During the 2015-16 influenza season (October 4, 2015-May 21, 2016) in the United States, influenza activity* was lower and peaked later compared with the previous three seasons (2012-13, 2013-14, and 2014-15). Activity remained low from October 2015 until late December 2015 and peaked in mid-March 2016. During the most recent 18 influenza seasons (including this season), only two other seasons have peaked in March (2011-12 and 2005-06). Overall influenza activity was moderate this season, with a lower percentage of outpatient visits for influenza-like illness (ILI),(†) lower hospitalization rates, and a lower percentage of deaths attributed to pneumonia and influenza (P&I) compared with the preceding three seasons. Influenza A(H1N1)pdm09 viruses predominated overall, but influenza A(H3N2) viruses were more commonly identified from October to early December, and influenza B viruses were more commonly identified from mid-April through mid-May. The majority of viruses characterized this season were antigenically similar to the reference viruses representing the recommended components of the 2015-16 Northern Hemisphere influenza vaccine (1). This report summarizes influenza activity in the United States during the 2015-16 influenza season (October 4, 2015-May 21, 2016)(§) and reports the vaccine virus components recommended for the 2016-17 Northern Hemisphere influenza vaccines.

Summary Influenza-like illness was noted in people and pigs in attendance at an Ohio county fair in August 2007. The morbidity rate in swine approached 100% within 1–2 days of initial clinical signs being recognized, and approximately two dozen people developed influenza-like illness. Triple-reassortant swine H1N1 influenza viruses were identified in both pigs and people at the fair. The identified viruses (A/Sw/OH/511445/2007, A/Ohio/01/2007, and A/Ohio/02/2007) were similar to H1N1 swine influenza viruses currently found in the U.S. swine population. This case illustrates the possibility of transmission of swine influenza in settings where there is close human/swine interaction.

Item does not contain fulltext BACKGROUND: In Africa, recent surveillance has demonstrated a high burden of influenza, but influenza vaccine is rarely used. In Kenya, a country with a tropical climate, influenza has been shown to circulate year-round, like in other tropical countries. METHODS: During 3 months in 2010 and 2011 and 2 months in 2012, the Kenya Medical Research Institute/Centers for Disease Control and Prevention-Kenya offered free injectable trivalent inactivated influenza vaccine to children 6 months to 10 years old in 2 resource-poor communities in Kenya-Kibera and Lwak (total population ~50,000). We conducted a case-control study to evaluate vaccine effectiveness (VE) in preventing laboratory-confirmed influenza associated with influenza-like illness and acute lower respiratory illness. RESULTS: Of the approximately 18,000 eligible children, 41%, 48% and 51% received at least 1 vaccine in 2010, 2011 and 2012, respectively; 30%, 36% and 38% were fully vaccinated. VE among fully vaccinated children was 57% [95% confidence interval (CI): 29% to 74%] during a 6-month follow-up period, 39% (95% CI: 17% to 56%) during a 9-month follow-up period and 48% (95% CI: 32% to 61%) during a 12-month follow-up period. For the 12-month follow-up period, VE was statistically significant in children

Serological techniques play a critical role in various aspects of influenza surveillance, vaccine development and evaluation, and sometimes in diagnosis, particularly for novel influenza virus infections of humans. Because individuals are repeatedly exposed to antigenically and genetically diverse influenza viruses over a lifetime, the gold standard for detection of a recent influenza virus infection or response to current vaccination is the demonstration of a seroconversion, a fourfold or greater rise in antibody titer relative to a baseline sample, to a circulating influenza strain or vaccine component. The hemagglutination-inhibition assay remains the most widely used assay to detect strain-specific serum antibodies to influenza. The hemagglutination-inhibition assay is also used to monitor antigenic changes among influenza viruses which are constantly evolving; such antigenic data is essential for consideration of changes in influenza vaccine composition. The use of the hemagglutinin-specific microneutralization assay has increased, in part, owing to its sensitivity for detection of human antibodies to novel influenza viruses of animal origin. Neutralization assays using replication-incompetent pseudotyped particles may be advantageous in some laboratory settings for detection of antibodies to influenza viruses with heightened biocontainment requirements. The use of standardized protocols and antibody standards are important steps to improve reproducibility and interlaboratory comparability of results of serologic assays for influenza viruses.

We report shedding duration of 2009 pandemic influenza A (pH1N1) virus from a school-associated outbreak in Pennsylvania during May through June 2009. Outbreak-associated students or household contacts with influenza-like illness (ILI) onset within 7 days of interview were recruited. Nasopharyngeal specimens, collected every 48 hours until 2 consecutive nonpositive tests, underwent real-time reverse transcriptase polymerase chain reaction (rRT-PCR) and culture for pH1N1 virus. Culture-positive specimens underwent virus titrations. Twenty-six (median age, 8 years) rRT-PCR-positive persons, for pH1N1 virus, were included in analysis. Median shedding duration from fever onset by rRT-PCR was 6 days (range, 1-13) and 5 days (range, 1-7) by culture. Following fever resolution virus was isolated for a median of 2 days (range, 0-5). Highest and lowest virus titers detected, 2 and 5 days following fever onset, were 3.2 and 1.2 log(10) TCID(50)/mL respectively. Overall, shedding duration in children and adults were similar to seasonal influenza viruses.

Knowledge from early outbreaks is limited regarding the virus detection and illness duration of the 2009 pandemic influenza A (H1N1) infections. During the period from April to May 2009 in Texas, we collected serial nasopharyngeal (NP) and stool specimens from 35 participants, testing by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) and culture. The participants were aged 2 months to 71 years; 25 (71%) were under 18. The median duration of measured fever was 3.0 days and of virus detection in NP specimens was 4.2 days; however, few specimens were collected between days 5-9. The duration of virus detection (4.2 days) was similar to the duration of fever (3.5 days) (RR, 1.14; 95% CI, .66-1.95; P = .8), but was shorter than the duration of cough (11.0 days) (RR, .41; 95% CI, .24―.68; P < .001). We detected viral RNA in two participants' stools. All cultures were negative. This investigation suggests that the duration of virus detection was likely similar to the seasonal influenza virus.

The main aim of this study was to compare the response to trivalent inactivated influenza vaccine in children who received a kidney transplant and were on steroid-free versus steroid-based immunosuppression. Groups: 1. Kidney transplant recipients on steroid-free immunosuppression (n = 27); 2. Kidney transplant recipients on steroid-based immunosuppression (n = 39); 3. Healthy controls (n = 21). Hemagglutination inhibition titers against 2007–2008 A/H1N1 and A/H3N2 and B strains were measured before and 8 weeks postvaccination. Postvaccination geometric mean titers to A/H1N1 were significantly lower among both transplant groups than controls (p = 0.025 and 0.015, respectively). Postvaccination titers to H3N2 and B strains were not statistically different between groups. Proportions of participants developing seroprotection were not different among groups. Both kidney transplant groups seroconverted less than controls for A/H1N1 (p = 0.0002) and were no different from controls for B. For A/H3N2, the steroid-free group had the weakest seroconversion (p = 0.008), possibly due to mycophenolate-enhanced exposure and a younger age. Overall, children after kidney transplantation demonstrated a good serologic response to the inactivated influenza vaccine although somewhat lower than controls. Steroid-free immunosuppression did not seem to present an advantage in antibody response. Data on inactivated influenza vaccine safety and efficacy was collected and demonstrated absence of acute rejection or laboratory-proven influenza for 6 months postvaccination.

Seasonal influenza is a contagious respiratory illness that annually affects millions of people worldwide. To identify currently circulating influenza virus subtypes, the Centers for Disease Control and Prevention's International Reagent Resource distributes the World Health Organization (WHO) influenza reagent kits, which are used globally by testing laboratories for influenza surveillance. The data generated by the kits aid in strain selection for the influenza vaccine each season. The use of animals to produce high quality and quantities of antibodies is critical to the production of these kits. In this study, we assessed the effects and efficacy of repeated sampling from automated plasmapheresis in goats. Analysis of blood samples demonstrated that repeated automated plasmapheresis procedures did not adversely affect the immediate or long-term health of goats. Further, our results indicate that repeated plasmapheresis in goats was capable of generating 2 liters of antibody-rich plasma per goat per week. This volume is sufficient to produce enough WHO influenza kits to conduct over 1 million tests. Thus, we have shown that the rapid production of plasma in goats can positively impact the public health preparedness and response to influenza.

Background: Pneumonia is the leading cause of child mortality worldwide. The role of influenza in childhood pneumonia in tropical developing countries is poorly understood. We undertook population-based surveillance among low-income urban preschool children to determine its role in childhood pneumonia. Methods: Longitudinal prospective active surveillance was conducted among randomly selected households in a poor urban area of Dhaka. Nasopharyngeal washes were collected from 1 in 5 children for influenza culture isolation. Clinical data were collected at clinical presentation and through the illness course. Results: From April 1, 2004 through December 31, 2007, 12,062 children presented in clinic with eligible febrile and respiratory illnesses, from whom 321 influenza isolates were obtained from 2370 nasopharyngeal washes (13.5%), representing 16,043 child-years of observation (adjusted influenza incidence 102 episodes/1000 child-years). There were 8198 pneumonia episodes during the period (pneumonia incidence 511 episodes/ 1000 child-years). Ninety influenza-positive children (28%) developed pneumonia during their illness. Among influenza culture-positive children, those with pneumonia were younger than those without (23.4 vs. 29.7 months, ANOVA: P 0.001). Pneumonia was more commonly associated with Influenza A (H3N2) than either A (H1N1) or B infections (ageadjusted relative odds (RO) 2.98, 95% CI: 1.56, 5.71 and 2.75, 95% CI: 1.52, 4.98, respectively). Influenza was associated with 10% all childhood pneumonia. Conclusions: Influenza is a major contributor to childhood pneumonia both through high influenza infection incidence and high pneumonia prevalence among infected children. Its contribution to early childhood pneumonia appears under-appreciated in high pneumonia-endemic tropical settings. Influenza vaccine trials against childhood pneumonia are warranted.

Triple-reassortant swine influenza A (H1) viruses--containing genes from avian, human, and swine influenza viruses--emerged and became enzootic among pig herds in North America during the late 1990s.We report the clinical features of the first 11 sporadic cases of infection of humans with triple-reassortant swine influenza A (H1) viruses reported to the Centers for Disease Control and Prevention, occurring from December 2005 through February 2009, until just before the current epidemic of swine-origin influenza A (H1N1) among humans. These data were obtained from routine national influenza surveillance reports and from joint case investigations by public and animal health agencies.The median age of the 11 patients was 10 years (range, 16 months to 48 years), and 4 had underlying health conditions. Nine of the patients had had exposure to pigs, five through direct contact and four through visits to a location where pigs were present but without contact. In another patient, human-to-human transmission was suspected. The range of the incubation period, from the last known exposure to the onset of symptoms, was 3 to 9 days. Among the 10 patients with known clinical symptoms, symptoms included fever (in 90%), cough (in 100%), headache (in 60%), and diarrhea (in 30%). Complete blood counts were available for four patients, revealing leukopenia in two, lymphopenia in one, and thrombocytopenia in another. Four patients were hospitalized, two of whom underwent invasive mechanical ventilation. Four patients received oseltamivir, and all 11 recovered from their illness.From December 2005 until just before the current human epidemic of swine-origin influenza viruses, there was sporadic infection with triple-reassortant swine influenza A (H1) viruses in persons with exposure to pigs in the United States. Although all the patients recovered, severe illness of the lower respiratory tract and unusual influenza signs such as diarrhea were observed in some patients, including those who had been previously healthy.

Enhanced surveillance was implemented in the United States for human infection with influenza A viruses that could not be subtyped. Specimens were sent to the Centers for Disease Control and Prevention for real-time reverse-transcriptase–polymerase-chain-reaction confirmatory testing for S-OIV. RESULTS From April 15 through May 5, a total of 642 confirmed cases of S-OIV infection were identified in 41 states. The ages of patients ranged from 3 months to 81 years; 60% of patients were 18 years of age or younger. Of patients with available data, 18% had recently traveled to Mexico, and 16% were identified from school outbreaks of S-OIV infection. The most common presenting symptoms were fever (94% of patients), cough (92%), and sore throat (66%); 25% of patients had diarrhea, and 25% had vomiting. Of the 399 patients for whom hospitalization status was known, 36 (9%) required hospitalization. Of 22 hospitalized patients with available data, 12 had characteristics that conferred an increased risk of severe seasonal influenza, 11 had pneumonia, 8 required admission to an intensive care unit, 4 had respiratory failure, and 2 died. The S-OIV was determined to have a unique genome composition that had not been identified previously. CONCLUSIONS A novel swine-origin influenza A virus was identified as the cause of outbreaks of febrile respiratory infection ranging from self-limited to severe illness. It is likely that the number of confirmed cases underestimates the number of cases that have occurred.

Item does not contain fulltext INTRODUCTION: Every year the World Health Organization (WHO) recommends which influenza virus strains should be included in a northern hemisphere (NH) and a southern hemisphere (SH) influenza vaccine. To determine the best vaccine formulation for Kenya, we compared influenza viruses collected in Kenya from April 2007 to May 2013 to WHO vaccine strains. METHODS: We collected nasopharyngeal and oropharyngeal (NP/OP) specimens from patients with respiratory illness, tested them for influenza, isolated influenza viruses from a proportion of positive specimens, tested the isolates for antigenic relatedness to vaccine strains, and determined the percentage match between circulating viruses and SH or NH influenza vaccine composition and schedule. RESULTS: During the six years, 7.336 of the 60,072 (12.2%) NP/OP specimens we collected were positive for influenza: 30,167 specimens were collected during the SH seasons and 3717 (12.3%) were positive for influenza; 2903 (78.1%) influenza A, 902 (24.2%) influenza B, and 88 (2.4%) influenza A and B positive specimens. We collected 30,131 specimens during the NH seasons and 3978 (13.2%) were positive for influenza; 3181 (80.0%) influenza A, 851 (21.4%) influenza B, and 54 (1.4%) influenza A and B positive specimens. Overall, 362/460 (78.7%) isolates from the SH seasons and 316/338 (93.5%) isolates from the NH seasons were matched to the SH and the NH vaccine strains, respectively (p

GNSS signal can be widely used in outdoor environment. However, due to the barrier of walls, GNSS signal becomes too weak to be used in indoor environment. This paper analyzed the Wi-Fi based indoor positioning method, which is mostly widely researched, introduced a DTMB based indoor positioning method and confirmed its feasibility. By using the KNN algorithm and the DTMB signal’s location fingerprint, the indoor positioning system proposed by this paper can locate any unknown nodes inside the room. And also some tests were designed to measure the positioning accuracy. Test results showed that the accuracy of the DTMB based indoor positioning system is similar to the Wi-Fi based positioning system. The new DTMB based indoor positioning method can be a useful complement to the existing indoor positioning methods.

Summary Background Adamantanes have been used to treat influenza A virus infections for many years. Studies have shown a low incidence of resistance to these drugs among circulating influenza viruses; however, their use is rising worldwide and drug resistance has been reported among influenza A (H5N1) viruses isolated from poultry and human beings in Asia. We sought to assess adamantane resistance among influenza A viruses isolated during the past decade from countries participating in WHO's global influenza surveillance network. Methods We analysed data for influenza field isolates that were obtained worldwide and submitted to the WHO Collaborating Center for Influenza at the US Centers for Disease Control and Prevention between Oct 1, 1994, and Mar 31, 2005. We used pyrosequencing, confirmatory sequence analysis, and phenotypic testing to detect drug resistance among circulating influenza A H3N2 (n=6524), H1N1 (n=589), and H1N2 (n=83) viruses. Findings More than 7000 influenza A field isolates were screened for specific aminoacid substitutions in the M2 gene known to confer drug resistance. During the decade of surveillance a significant increase in drug resistance was noted, from 0·4% in 1994–1995 to 12·3% in 2003–2004. This increase in the proportion of resistant viruses was weighted heavily by those obtained from Asia with 61% of resistant viruses isolated since 2003 being from people in Asia. Interpretation Our data raise concerns about the appropriate use of adamantanes and draw attention to the importance of tracking the emergence and spread of drug-resistant influenza A viruses.