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Hydrilla is an invasive aquatic plant that has rapidly spread through many inland water bodies across the globe by outcompeting native aquatic plants. The negative impacts of hydrilla invasion have become a concern for water resource management authorities, power companies, and environmental scientists. The early detection of hydrilla infestation is very important to reduce the costs associated with control and removal efforts of this invasive species. Therefore, in this study, we aimed to develop a tool for rapid, frequent, and large-scale monitoring and predicting spatial extent of hydrilla habitat. This was achieved by integrating in situ and Landsat 8 Operational Land Imager satellite data for Lake J. Strom Thurmond, the largest US Army Corps of Engineers lake east of the Mississippi River, located on the border of Georgia and South Carolina border. The predictive model for presence of hydrilla incorporated radiometric and physical measurements, including remote-sensing reflectance, Secchi disk depth (SDD), light-attenuation coefficient (Kd), maximum depth of colonization (Zc), and percentage of light available through the water column (PLW). The model-predicted ideal habitat for hydrilla featured high SDD, Zc, and PLW values, low values of Kd. Monthly analyses based on satellite images showed that hydrilla starts growing in April, reaches peak coverage around October, begins retreating in the following months, and disappears in February. Analysis of physical and meteorological factors (i.e., water temperature, surface runoff, net inflow, precipitation) revealed that these parameters are closely associated with hydrilla extent. Management agencies can use these results not only to plan removal efforts but also to evaluate and adapt their current mitigation efforts.
Thermoelectronic energy conversion can potentially provide an exceptionally efficient way to convert heat into electric power. Key components of such converters are materials with designed, small work functions. We present the principles of thermoelectronic energy conversion and discuss the advantages and challenges of the conversion process, as well the state of the art of the respective research.
We aimed to evaluate emergency medical services (EMS) data as disaster metrics and to assess stress in surrounding hospitals and a municipal network after the closure of Bellevue Hospital during Hurricane Sandy in 2012.
We retrospectively reviewed EMS activity and call types within New York City’s 911 computer-assisted dispatch database from January 1, 2011, to December 31, 2013. We evaluated EMS ambulance transports to individual hospitals during Bellevue’s closure and incremental recovery from urgent care capacity, to freestanding emergency department (ED) capability, freestanding ED with 911-receiving designation, and return of inpatient services.
A total of 2,877,087 patient transports were available for analysis; a total of 707,593 involved Manhattan hospitals. The 911 ambulance transports disproportionately increased at the 3 closest hospitals by 63.6%, 60.7%, and 37.2%. When Bellevue closed, transports to specific hospitals increased by 45% or more for the following call types: blunt traumatic injury, drugs and alcohol, cardiac conditions, difficulty breathing, “pedestrian struck,” unconsciousness, altered mental status, and emotionally disturbed persons.
EMS data identified hospitals with disproportionately increased patient loads after Hurricane Sandy. Loss of Bellevue, a public, safety net medical center, produced statistically significant increases in specific types of medical and trauma transports at surrounding hospitals. Focused redeployment of human, economic, and social capital across hospital systems may be required to expedite regional health care systems recovery. (Disaster Med Public Health Preparedness. 2016;10:333–343)
be a vector space of dimension
over the finite field
-analog of a Steiner system (also known as a
-Steiner system), denoted
, is a set
-dimensional subspaces of
such that each
-dimensional subspace of
is contained in exactly one element of
-Steiner systems are known only for
, and in the trivial cases
. In this paper, the first nontrivial
-Steiner systems with
are constructed. Specifically, several nonisomorphic
are found by requiring that their automorphism groups contain the normalizer of a Singer subgroup of
. This approach leads to an instance of the exact cover problem, which turns out to have many solutions.
Experiments on the National Ignition Facility show that multi-dimensional effects currently dominate the implosion performance. Low mode implosion symmetry and hydrodynamic instabilities seeded by capsule mounting features appear to be two key limiting factors for implosion performance. One reason these factors have a large impact on the performance of inertial confinement fusion implosions is the high convergence required to achieve high fusion gains. To tackle these problems, a predictable implosion platform is needed meaning experiments must trade-off high gain for performance. LANL has adopted three main approaches to develop a one-dimensional (1D) implosion platform where 1D means measured yield over the 1D clean calculation. A high adiabat, low convergence platform is being developed using beryllium capsules enabling larger case-to-capsule ratios to improve symmetry. The second approach is liquid fuel layers using wetted foam targets. With liquid fuel layers, the implosion convergence can be controlled via the initial vapor pressure set by the target fielding temperature. The last method is double shell targets. For double shells, the smaller inner shell houses the DT fuel and the convergence of this cavity is relatively small compared to hot spot ignition. However, double shell targets have a different set of trade-off versus advantages. Details for each of these approaches are described.
Despite immense achievements in the past century in hygiene control, and the development of vaccines and antibiotics, infectious diseases continue to pose a tremendous threat to public health globally. There are still devastating infections for which there are no effective vaccines or antimicrobial therapies. Moreover, the problem of drug resistance in bacteria and viral populations and the increasing appreciation that pathologies resulting from infections are responsible for a number of chronic conditions, are creating an ever-growing need for novel preventive and therapeutic approaches. In line with this, a new host-targeted approach has been suggested for antimicrobial drug research that exploits the central role of the host cell during infection. Decades of research have taught us that infections are supported by host cell functions, and that infection pathology is frequently host dependent. Accordingly, the pharmacological targeting of host cell factors promises novel opportunities to prevent and treat infectious disease. Such an approach may be anticipated to expand the number of druggable targets, produce broad-spectrum compounds and impede the generation of resistance. The discovery of RNA interference (RNAi) has created opportunities to explore gene functions in cellular systems in a targeted manner. RNAi loss-of-function approaches have proved invaluable for the identification of host proteins important for pathogen viability. These approaches can be applied on a high-throughput scale, which demands sophisticated liquid handling and high-content image analysis. Here, we provide an overview of the current status of high-content screening (HCS) in loss-of-function analyses in infectious disease research and discuss how these powerful techniques can be applied to identify host factors with previously unknown roles in infection and its pathology.
The challenge of fighting infectious diseases
Infections by pathogenic species of bacteria, viruses, fungi and protozoa have had considerable impact on mankind throughout history. Advances in our understanding of the importance of hygiene control, and later, improvements in diagnostics and the development and successful employment of vaccines and antimicrobial drugs, have substantially benefited human health, and provided social and economic benefits.
Hospital Ebola preparation is underway in the United States and other countries; however, the best approach and resources involved are unknown.
To examine costs and challenges associated with hospital Ebola preparation by means of a survey of Society for Healthcare Epidemiology of America (SHEA) members.
Electronic survey of infection prevention experts.
A total of 257 members completed the survey (221 US, 36 international) representing institutions in 41 US states, the District of Columbia, and 18 countries. The 221 US respondents represented 158 (43.1%) of 367 major medical centers that have SHEA members and included 21 (60%) of 35 institutions recently defined by the US Centers for Disease Control and Prevention as Ebola virus disease treatment centers. From October 13 through October 19, 2014, Ebola consumed 80% of hospital epidemiology time and only 30% of routine infection prevention activities were completed. Routine care was delayed in 27% of hospitals evaluating patients for Ebola.
Convenience sample of SHEA members with a moderate response rate.
Hospital Ebola preparations required extraordinary resources, which were diverted from routine infection prevention activities. Patients being evaluated for Ebola faced delays and potential limitations in management of other diseases that are more common in travelers returning from West Africa.
Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (∼42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (∼5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
Although the physical remains of early hominins are often touted as the most important aspects of the palaeoanthropological record, the evidence of our hominin ancestry in pieces of stone chipped to make sharp edges is far more plentiful. Stone artifacts represent the dawn of human material culture. Currently there is no reason to believe that our early Pliocene ancestors did not use organic tools prior to the appearance of the earliest stone industries (Panger et al. 2002). However, the durability of the stone artifact record provides archaeologists with a rich record of behaviour over millions of years. The earliest evidence of tool use in the archaeological record comes from indirect evidence of butchery practices. The new discovery of marks indicating butchery on two bones from the Dikika region of Ethiopia confirms the use of stone as a medium for tool use at 3.2 million years ago (Ma) (McPherron et al. 2010). However, the earliest evidence of chipped stone artifacts begins some 2.6 Ma. This record extends through to the Holocene. This chapter will focus almost exclusively on the human use of stone tools in Africa from 2.6 Ma until around 1.5 Ma. The assemblages of stone tools from Africa have frequently been assigned to the classic tripartite system (i.e., Earlier, Middle and Later Stone Age; Goodwin 1945) that was inherited from a European framework of stone industries (Lartet & Christy 1865–75). This chapter covers the earliest stages of stone-tool production, referred to as the Earlier Stone Age, and some of the beginnings of the Middle Stone Age. It will use major regions of Africa as a framework, mostly because the history of research in certain areas influences the study of the sequences of industries. In addition, major units of time that do not necessarily correspond with industrial names (e.g., Developed Oldowan) will provide further structure for this chapter. However, these units of time do not represent any meaningful temporal divisions.
This white paper identifies knowledge gaps and new challenges in healthcare epidemiology research, assesses the progress made toward addressing research priorities, provides the Society for Healthcare Epidemiology of America (SHEA) Research Committee's recommendations for high-priority research topics, and proposes a road map for making progress toward these goals. It updates the 2010 SHEA Research Committee document, “Charting the Course for the Future of Science in Healthcare Epidemiology: Results of a Survey of the Membership of SHEA,” which called for a national approach to healthcare-associated infections (HAIs) and a prioritized research agenda. This paper highlights recent studies that have advanced our understanding of HAIs, the establishment of the SHEA Research Network as a collaborative infrastructure to address research questions, prevention initiatives at state and national levels, changes in reporting and payment requirements, and new patterns in antimicrobial resistance.
Considering the discussion on implementing routine dementia screening in Germany, the objective of the current study was to validate the German version of the Perceptions Regarding Investigational Screening for Memory in Primary Care (PRISM-PC) questionnaire and to determine the acceptance of Alzheimer's disease screening in elderly German adults.
The German version of the PRISM-PC was administered to a subsample of participants who attended the Berlin Aging Study II (n = 506). The questionnaire was validated by exploratory as well as confirmatory factor analysis.
Regarding acceptance of Alzheimer's disease screening (Section B) a single factor structure fitted best. In terms of attitudes regarding Alzheimer's disease (Section D), a hierarchical factor structure was modeled with the higher-order factor “Harms” covering the domains “Family Burden,” “Dependence,” “Emotional Suffering,” “Stigma,” and “Medical Care” on the one hand and the domain “Future Planning” on the other hand. Internal consistency of the different scales reached from α = 0.67 to α = 0.94. Overall, 71.2% of the participants indicated that they wanted to be screened for Alzheimer's disease on a regular basis.
This study suggests that acceptance can reliably be assessed with the section “Acceptance of Alzheimer's disease screenings” of the German PRISM-PC questionnaire. Furthermore, the majority of elderly German adults would like to be screened for Alzheimer's disease regularly, which might be an effective starting point in order to implement routine dementia screenings. As the sample is a convenience sample of (relatively) healthy older adults, generalizability of these results is limited.
We developed a new phage-typing method and evaluated its application in combination with XbaI macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) as a useful tool for the long-term epidemiology of Salmonella enterica serovar Infantis. In this study, we investigated 1008 S. Infantis isolates recovered from humans, various animal species and food products from 1973 to 2009. The typing scheme is based on 17 typing phages, defining 61 different patterns within the strain collection. The experiments showed that phage typing is a reliable method for differentiation of outbreaks and sporadic clinical cases as well as for elucidation of chains of transmission. The combined analysis of phage typing and PFGE revealed the existence of epidemic clones with a high stability over time like PT29/XB27 which was identified in nosocomial salmonellosis, community outbreaks as well as in broiler chickens from 2002 to 2009.
The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.
Antenatal corticosteroids are used to augment fetal lung maturity in human pregnancy. Dexamethasone (DEX) is also used to treat congenital adrenal hyperplasia of the fetus in early pregnancy. We previously reported effects of synthetic corticosteroids given to sheep in early or late gestation on pregnancy length and fetal cortisol levels and glucocorticoids alter plasma insulin-like growth factor (IGF) and insulin-like growth factor binding protein (IGFBP) concentrations in late pregnancy and reduce fetal weight. The effects of administering DEX in early pregnancy on fetal organ weights and betamethasone (BET) given in late gestation on weights of fetal brain regions or organ development have not been reported. We hypothesized that BET or DEX administration at either stage of pregnancy would have deleterious effects on fetal development and associated hormones. In early pregnancy, DEX was administered as four injections at 12-hourly intervals over 48 h commencing at 40–42 days of gestation (dG). There was no consistent effect on fetal weight, or individual fetal organ weights, except in females at 7 months postnatal age. When BET was administered at 104, 111 and 118 dG, the previously reported reduction in total fetal weight was associated with significant reductions in weights of fetal brain, cerebellum, heart, kidney and liver. Fetal plasma insulin, leptin and triiodothyronine were also reduced at different times in fetal and postnatal life. We conclude that at the amounts given, the sheep fetus is sensitive to maternal administration of synthetic glucocorticoid in late gestation, with effects on growth and metabolic hormones that may persist into postnatal life.
Polyurethanes are widely used, from medical devices to electrical materials to consumer goods. These materials have chemical stability issues which impact the mechanical stability. Infrared micro spectroscopy has been used to study polyurethane degradation, but due to experimental limitations, samples examined were no smaller than approximately 15 microns on a side. Because of the complex chemistry of urethanes, chemical examination of the material on a much higher spatial resolution scale would be valuable.
A relatively new technique, Attenuated Total Reflection Fourier Transform Infrared Spectrochemical MicroImaging has been used to examine degraded polyester urethanes. Rather than using a single-element detector, a two dimensional array detector generates thousands of spectra simultaneously. In addition, a germanium prism generates a magnification effect; resulting in a significantly higher spatial resolution. The net output of the analysis is a hypercube of high resolution infrared spectra showing urethane degradation progression on a much smaller spatial scale than was previously possible.
Glaciers on King George Island, Antarctica, have shown retreat and surface lowering in recent decades, concurrent with increasing air temperatures. A large portion of the glacier perimeter is ocean-terminating, suggesting possible large mass losses due to calving and submarine melting. Here we estimate the ice discharge into the ocean for the King George Island ice cap. L-band synthetic aperture radar images covering the time-span January 2008 to January 2011 over King George Island are processed using an intensity-tracking algorithm to obtain surface velocity measurements. Pixel offsets from 40 pairs of radar images are analysed and inverted to estimate a weighted average surface velocity field. Ice thicknesses are derived from simple principles of ice flow mechanics using the computed surface velocity fields and in situ thickness data. The maximum ice surface speeds reach >225 m a-1, and the total ice discharge for the analysed flux gates of King George Island is estimated to be 0.720 ± 0.428 Gt a−1, corresponding to a specific mass loss of 0.64 ± 0.38 m w.e. a-1 over the area of the entire ice cap (1127 km2).