2,356 research outputs found
The dynamism of salt crust patterns on playas
Playas are common in arid environments and can be major sources of mineral dust that can influence global climate. These landforms typically form crusts that limit evaporation and dust emission, modify surface erosivity and erodibility, and can lead to over prediction or under prediction of (1) dust-emission potential and (2) water and heat fluxes in energy balance modeling. Through terrestrial laser scanning measurements of part of the Makgadikgadi Pans of Botswana (a Southern Hemisphere playa that emits significant amounts of dust), we show that over weeks, months, and a year, the shapes of these surfaces change considerably (ridge thrusting of >30 mm/week) and can switch among continuous, ridged, and degraded patterns. Ridged pattern development changes the measured aerodynamic roughness of the surface (as much as 3 mm/week). The dynamic nature of these crusted surfaces must be accounted for in dust entrainment and moisture balance formulae to improve regional and global climate models
Determination of Trace Silicone Contamination on Composites by Quantitative XPS and LIBS
Surface treatment and surface characterization techniques are critical to ensure that adherends are chemically activated and free of contaminants prior to adhesive bonding. Silicone contamination from mold-release agents and other sources can interfere with interfacial bonding, decreasing the durability and performance of bonded composite structures. Tools and methods are needed that can be used in a production environment to reliably detect low levels of contaminants in a rapid, simple, and cost-effective manner to improve bond reliability. In this work, surface characterization of carbon fiber reinforced polymer (CFRP) composites was performed using laser induced breakdown spectroscopy (LIBS) and the results were compared with those obtained from X-ray photoelectron spectroscopy (XPS). The objective was to investigate the ability to quantify the surface species measured by LIBS since it offers many advantages over XPS in terms of ease of use, sample preparation, and real-time results. The as-processed CFRP panels had trace surface silicone contamination from the fabrication process, the source of which was not investigated. The composites were laser treated at select average laser power levels, resulting in varying levels of contamination reduction. The Si atomic percentage measurements using XPS were conducted both before and after laser ablation. The XPS results were compared with those obtained from LIBS to assess the reliability of each technique for surface contaminant characterization. The results showed an excellent correlation in Si atomic concentration between the two techniques
Decrease in total aneurysm-related deaths in the era of endovascular aneurysm repair
ObjectiveWith the expansion of elective abdominal aortic aneurysm (AAA) repair after the introduction of endovascular aneurysm repair (EVAR), there is a concern that even with a lower operative mortality there could be an increasing number of aneurysm-related deaths. To evaluate this, we looked at national trends in AAA repair volume as well as mortality rates after intact and ruptured AAA repair encompassing the introduction of EVAR.MethodsPatients with intact or ruptured AAA undergoing open repair or EVAR and all those with a diagnosis of ruptured AAA were identified within the 1993 to 2005 Nationwide Inpatient Sample database using International Classification of Diseases, 9th Revision, diagnosis and procedure codes. The number of repairs, number of rupture diagnoses without repair, number of deaths, and associated mortality rates were measured for each year of the database. Outcomes (mean annual volumes) were compared from the pre-EVAR era (1993 to 1998) with the post-EVAR era (2001 to 2005).ResultsSince its introduction, EVAR increased steadily and accounted for 56% of repairs yet only 27% of the deaths for intact repairs in 2005. The mean annual number of intact repairs increased from 36,122 in the pre-EVAR era to 38,901 in the post-EVAR era, whereas the mean annual number of deaths related to intact AAA repair decreased from 1693 pre-EVAR to 1207 post-EVAR (P < .0001). Mortality for all intact AAA repair decreased from 4.0% to 3.1% (P < .0001) pre-EVAR and post-EVAR, but open repair mortality was unchanged (open repair, 4.7% to 4.5%, P = .31; EVAR, 1.3%). During the same time, the mean annual number of ruptured repairs decreased from 2804 to 1846, and deaths from ruptured AAA repairs decreased from 2804 to 1846 (P < .0001). Mortality for ruptured AAA repair decreased from 44.3% to 39.9% (P < .0001) pre-EVAR and post-EVAR (open repair, 44.3% to 39.9%, P < .001; EVAR, 32.4%). The overall mean annual number of ruptured AAA diagnoses (9979 to 7773, P < .0001) and overall mean annual deaths from a ruptured AAA decreased post-EVAR (5338 to 3901, P < .0001).ConclusionSince the introduction of EVAR, the annual number of deaths from intact and ruptured AAA has significantly decreased. This coincided with an increase in intact AAA repair after the introduction of EVAR and a decrease in ruptured AAA diagnosis and repair volume
Equine nutrition: a survey of perceptions and practices of horse owners undertaking a massive open online course in equine nutrition
An online survey was designed to ascertain the following information: demographics, current feeding practices, and perceptions and knowledge of equine nutrition, including nutrition-related disorders. Response rate was 34% (6,538 respondents). More than 80% of respondents were horse owners or caretakers, with the majority owning between one and five horses (75%) aged 5 years and older (74%). Most kept their horses for pleasure (54%), with 33% using them mostly for competition and 13% using them for an equal mix of both pleasure and competition. Concentrates were fed by the majority (87%), and more than 70% stated that their horses had some access to pasture. Over half of respondents (60%) regularly monitored their horses' weight, with most doing this monthly. Weight tapes were most commonly used (62%), although many reported to guess the weight of their horse(s) with very few (5%) using weight scales. Under half (46%) stated that they regularly used body condition scoring (BCS), many did not use BCS at all (24%), and some did not know what BCS was (10%). Of those that did use BCS, most (36%) did this monthly, with others weekly (25%), daily (14%), and when they remembered (15%). Overall knowledge of nutrition was reported by most as average (median, 3 on Likert scale—average); however, respondents were less knowledgeable on the management of nutrition-related disorders
A transient I band excess in the optical spectrum of the accreting millisecond pulsar SAX J1808.4-3658
The optical counterpart of the transient, millisecond X-ray pulsar SAX
J1808.4-3658 was observed in four colours (BVRI) for five weeks during the 2005
June-July outburst. The optical fluxes declined by ~2 magnitudes during the
first 16 days and then commenced quasi-periodic secondary outbursts, with
time-scales of several days, similar to those seen in 2000 and 2002. The
broadband spectra derived from these measurements were generally consistent
with emission from an X-ray heated accretion disc. During the first 16 days
decline in intensity the spectrum became redder. We suggest that the primary
outburst was initiated by a viscosity change driven instability in the inner
disc and note the contrast with another accreting millisecond pulsar, XTE
J0929--314, for which the spectrum becomes bluer during the decline. On the
night of 2005 June 5 (HJD 2453527) the I band flux was ~0.45 magnitudes
brighter than on the preceding or following nights whereas the BVR bands showed
no obvious enhancement. A Type I X-ray burst was detected by the RXTE
spacecraft during this I band integration. It seems unlikely that reprocessed
radiation from the burst was sufficient to explain the observed increase. We
suggest that a major part of the I band excess was due to synchrotron emission
triggered by the X-ray burst. Several other significant short duration changes
in V-I were detected. One occurred at about HJD 2453546 in the early phase of
the first secondary outburst and may be due to a mass transfer instability or
to another synchrotron emission event.Comment: 7 pages, 5 figures, accepted by MNRAS, 10 May 2006. Ver. 2 - larger
Table 2 + various modest text change
The Role of Databases in Areawide Pest Management
The simplest definition of the term \u27database\u27 is given in Webster\u27s dictionary as \u27a comprehensive collection of related data organized for convenient access, generally in a computer\u27 (Random House, 1996). This term appeared in the late 1960s because of the evolution of computer software and the need to distinguish the specialized computer systems for the storage and manipulation of data, called database management systems (DBMS) (Neufeld and Cornog, 1986). Today, the acronym \u27DBMS\u27 is universally understood within Information Technology (IT), just like the acronym \u27Bt\u27 for \u27Bacillus thuringiensis\u27 is in the field of biological pest control. At the present time there are numerous DBMS products available on the market. The most popular are Oracle©, dBase©, DB2©, MS SQL Server© and Access©. Access is a part of the Microsoft Office product and can be considered as a prototype of DBMS with limited functionality. These products vary in price and capacity, and therefore the budgetary constraints and the requirements of a particular database application determine their utility.
The evolution of database products has been rapid, reflecting advances in the theory of databases during the last 35-40 years. Beginning with simple data files with direct access, these database products now include very sophisticated file systems with complex interrelationships. More recently, there has been a series of new database applications named Relational Database Management Systems (RDBMS). Their development was a product of the advancement in IT, which forced DBMS to adapt. One of these advancements was the creation of distributed computer systems using local or wide-area networks (LAN/WAN) at the end of the 1980s and early 1990s (Date, 2003). These networks stimulated development of new methods for remote database connection, and the improvements of client/server technologies when databases are organized on a computer server separated from those remotely accessed and used to enter data. The uses of DBMS can be very diverse, but this chapter focuses on the application of DBMS in the field of biology, more specifically in entomology and integrated pest management (IPM)
The Role of Databases in Areawide Pest Management
The simplest definition of the term \u27database\u27 is given in Webster\u27s dictionary as \u27a comprehensive collection of related data organized for convenient access, generally in a computer\u27 (Random House, 1996). This term appeared in the late 1960s because of the evolution of computer software and the need to distinguish the specialized computer systems for the storage and manipulation of data, called database management systems (DBMS) (Neufeld and Cornog, 1986). Today, the acronym \u27DBMS\u27 is universally understood within Information Technology (IT), just like the acronym \u27Bt\u27 for \u27Bacillus thuringiensis\u27 is in the field of biological pest control. At the present time there are numerous DBMS products available on the market. The most popular are Oracle©, dBase©, DB2©, MS SQL Server© and Access©. Access is a part of the Microsoft Office product and can be considered as a prototype of DBMS with limited functionality. These products vary in price and capacity, and therefore the budgetary constraints and the requirements of a particular database application determine their utility.
The evolution of database products has been rapid, reflecting advances in the theory of databases during the last 35-40 years. Beginning with simple data files with direct access, these database products now include very sophisticated file systems with complex interrelationships. More recently, there has been a series of new database applications named Relational Database Management Systems (RDBMS). Their development was a product of the advancement in IT, which forced DBMS to adapt. One of these advancements was the creation of distributed computer systems using local or wide-area networks (LAN/WAN) at the end of the 1980s and early 1990s (Date, 2003). These networks stimulated development of new methods for remote database connection, and the improvements of client/server technologies when databases are organized on a computer server separated from those remotely accessed and used to enter data. The uses of DBMS can be very diverse, but this chapter focuses on the application of DBMS in the field of biology, more specifically in entomology and integrated pest management (IPM)
A novel, high-welfare methodology for evaluating poultry red mite interventions in vivo
Optimisation and use of a device for the on-hen in vivo feeding of all hematophagous stages of Dermanyssus gallinae is described. The sealed mesh device contains the mites and is applied to the skin of the hen’s thigh where mites can feed on the bird through a mesh which has apertures large enough to allow the mites’ mouth-parts to access to the bird but small enough to contain the mites. By optimising the depth and width of the mesh aperture size we have produced a device which will lead to both reduction and refinement in the use of animals in research, allowing the pre-screening of new vaccines and systemic acaricides/insecticides which have been developed for the control of these blood-feeding parasites before progressing to large field trials. For optimal use,the device should be constructed from 105μm aperture width, 63 μm depth, polyester mesh and the mites (irrespective of life stage) should be conditioned with no access to food for 3 weeks at 4 °C for optimal feeding and post-feeding survival
Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets.
AIMS/HYPOTHESIS: Intra-islet and gut-islet crosstalk are critical in orchestrating basal and postprandial metabolism. The aim of this study was to identify regulatory proteins and receptors underlying somatostatin secretion though the use of transcriptomic comparison of purified murine alpha, beta and delta cells. METHODS: Sst-Cre mice crossed with fluorescent reporters were used to identify delta cells, while Glu-Venus (with Venus reported under the control of the Glu [also known as Gcg] promoter) mice were used to identify alpha and beta cells. Alpha, beta and delta cells were purified using flow cytometry and analysed by RNA sequencing. The role of the ghrelin receptor was validated by imaging delta cell calcium concentrations using islets with delta cell restricted expression of the calcium reporter GCaMP3, and in perfused mouse pancreases. RESULTS: A database was constructed of all genes expressed in alpha, beta and delta cells. The gene encoding the ghrelin receptor, Ghsr, was highlighted as being highly expressed and enriched in delta cells. Activation of the ghrelin receptor raised cytosolic calcium levels in primary pancreatic delta cells and enhanced somatostatin secretion in perfused pancreases, correlating with a decrease in insulin and glucagon release. The inhibition of insulin secretion by ghrelin was prevented by somatostatin receptor antagonism. CONCLUSIONS/INTERPRETATION: Our transcriptomic database of genes expressed in the principal islet cell populations will facilitate rational drug design to target specific islet cell types. The present study indicates that ghrelin acts specifically on delta cells within pancreatic islets to elicit somatostatin secretion, which in turn inhibits insulin and glucagon release. This highlights a potential role for ghrelin in the control of glucose metabolism.This work was supported by the European Foundation for the
Study of Diabetes and Boehringer Ingelheim Basic Research Programme;
the Wellcome Trust (grants 106262/Z/14/Z, 106263/Z/14/Z and 100574/
Z/12/Z); the Medical Research Council Metabolic Diseases Unit (grants
MRC_MC_UU_12012/3 and MRC_MC_UU_12012/5); and the Novo
Nordisk Foundation
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