978 research outputs found
The economic value of remote sensing of earth resources from space: An ERTS overview and the value of continuity of service. Volume 5: Inland water resources
The economic value of an ERTS system in the area of inland water resources management is investigated. Benefits are attributed to new capabilities for managing inland water resources in the field of power generation, agriculture, and urban water supply. These benefits are obtained in the area of equal capability (cost savings) and increased capability (equal budget), and are estimated by applying conservative assumptions to Federal budgeting information, Congressional appropriation hearings, and ERTS technical capabilities
A parametric study of the value of hydrological information for irrigation and hydropower management of the Feather River
A case study analysis is presented of the relationships between improvements in the accuracy, frequency, and timeliness of information used in making hydrological forecasts and economic benefits in the areas of hydropower and irrigation. The area chosen for the case study is the Oroville Dam and Reservoir. Emphasis is placed on the use of timely and accurate mapping of the aerial extent of snow in the basin by earth resources survey systems such as LANDSAT. The subject of benefits resulting from improved runoff forecasts is treated in a generalized way without specifying the source of the improvements
Self-consistent Coulomb effects and charge distribution of quantum dot arrays
This paper considers the self-consistent Coulomb interaction within arrays of
self-assembled InAs quantum dots (QDs) which are embedded in a pn structure.
Strong emphasis is being put on the statistical occupation of the electronic QD
states which has to be solved self-consistently with the actual
three-dimensional potential distribution. A model which is based on a Green's
function formalism including screening effects is used to calculate the
interaction of QD carriers within an array of QDs, where screening due to the
inhomogeneous bulk charge distribution is taken into acount. We apply our model
to simulate capacitance-voltage (CV) characteristics of a pn structure with
embedded QDs. Different size distributions of QDs and ensembles of spatially
perodic and randomly distributed arrays of QDs are investigated.Comment: submitted to pr
The Role of TLR2 in Infection and Immunity
Toll-like receptors (TLRs) are recognition molecules for multiple pathogens, including bacteria, viruses, fungi, and parasites. TLR2 forms heterodimers with TLR1 and TLR6, which is the initial step in a cascade of events leading to significant innate immune responses, development of adaptive immunity to pathogens and protection from immune sequelae related to infection with these pathogens. This review will discuss the current status of TLR2 mediated immune responses by recognition of pathogen-associated molecular patterns (PAMPS) on these organisms. We will emphasize both canonical and non-canonical responses to TLR2 ligands with emphasis on whether the inflammation induced by these responses contributes to the disease state or to protection from diseases
Impact of Central Venous Catheter Type and Methods on Catheter-Related Colonization and Bacteraemia
A prospective, randomized, controlled, multi-centre clinical trial was performed to test the effectiveness of an antimicrobial central venous catheter (CVC) made of polyurethane integrated with silver, platinum and carbon black (Vantex). Adults expected to require a CVC for more than 60 h were eligible, and were randomized to receive the test or control catheter. All CVCs were inserted with new venipunctures using full aseptic technique. Following catheter removal, the distal tip and an intracutaneous segment were removed and cultured using semiquantitative and quantitative methods. Peripheral blood samples were obtained and cultured to confirm cases of catheter-related bloodstream infection (CRBSI). Bacterial and fungal organisms were identified by standard microbiological methods. Catheter placement was performed primarily in the intensive care unit (50%) or operating theatre (42%). Complete data could be evaluated for 539 patients (77%). The mean duration of CVC placement was 149.3h (six days). There were no significant differences in colonization or bacteraemia rates between the test and control catheters. The overall colonization rate was not particularly low (24.5%), and yet CVC-related bacteraemia occurred in only 1.4% of patients, and CRBSI occurred in only one patient from the control group (0.2%). Insertion site and dressing change frequency were significantly associated with the colonization rate. Although CVCs with antimicrobial features have been associated with a decrease in catheter-related colonization and bacteraemia, this study demonstrated that infection rates may depend more on non-catheter-related factors, such as adherence to infection control standards, selection of insertion site, duration of CVC placement, and dressing change frequency. As microbial resistance increases, clinicians should make maximal use of these processes to reduce catheter-related infections
Impact of Central Venous Catheter Type and Methods on Catheter-Related Colonization and Bacteraemia
A prospective, randomized, controlled, multi-centre clinical trial was performed to test the effectiveness of an antimicrobial central venous catheter (CVC) made of polyurethane integrated with silver, platinum and carbon black (Vantex). Adults expected to require a CVC for more than 60 h were eligible, and were randomized to receive the test or control catheter. All CVCs were inserted with new venipunctures using full aseptic technique. Following catheter removal, the distal tip and an intracutaneous segment were removed and cultured using semiquantitative and quantitative methods. Peripheral blood samples were obtained and cultured to confirm cases of catheter-related bloodstream infection (CRBSI). Bacterial and fungal organisms were identified by standard microbiological methods. Catheter placement was performed primarily in the intensive care unit (50%) or operating theatre (42%). Complete data could be evaluated for 539 patients (77%). The mean duration of CVC placement was 149.3h (six days). There were no significant differences in colonization or bacteraemia rates between the test and control catheters. The overall colonization rate was not particularly low (24.5%), and yet CVC-related bacteraemia occurred in only 1.4% of patients, and CRBSI occurred in only one patient from the control group (0.2%). Insertion site and dressing change frequency were significantly associated with the colonization rate. Although CVCs with antimicrobial features have been associated with a decrease in catheter-related colonization and bacteraemia, this study demonstrated that infection rates may depend more on non-catheter-related factors, such as adherence to infection control standards, selection of insertion site, duration of CVC placement, and dressing change frequency. As microbial resistance increases, clinicians should make maximal use of these processes to reduce catheter-related infections
Efficient Certified Resolution Proof Checking
We present a novel propositional proof tracing format that eliminates complex
processing, thus enabling efficient (formal) proof checking. The benefits of
this format are demonstrated by implementing a proof checker in C, which
outperforms a state-of-the-art checker by two orders of magnitude. We then
formalize the theory underlying propositional proof checking in Coq, and
extract a correct-by-construction proof checker for our format from the
formalization. An empirical evaluation using 280 unsatisfiable instances from
the 2015 and 2016 SAT competitions shows that this certified checker usually
performs comparably to a state-of-the-art non-certified proof checker. Using
this format, we formally verify the recent 200 TB proof of the Boolean
Pythagorean Triples conjecture
QRAT+: Generalizing QRAT by a More Powerful QBF Redundancy Property
The QRAT (quantified resolution asymmetric tautology) proof system simulates
virtually all inference rules applied in state of the art quantified Boolean
formula (QBF) reasoning tools. It consists of rules to rewrite a QBF by adding
and deleting clauses and universal literals that have a certain redundancy
property. To check for this redundancy property in QRAT, propositional unit
propagation (UP) is applied to the quantifier free, i.e., propositional part of
the QBF. We generalize the redundancy property in the QRAT system by QBF
specific UP (QUP). QUP extends UP by the universal reduction operation to
eliminate universal literals from clauses. We apply QUP to an abstraction of
the QBF where certain universal quantifiers are converted into existential
ones. This way, we obtain a generalization of QRAT we call QRAT+. The
redundancy property in QRAT+ based on QUP is more powerful than the one in QRAT
based on UP. We report on proof theoretical improvements and experimental
results to illustrate the benefits of QRAT+ for QBF preprocessing.Comment: preprint of a paper to be published at IJCAR 2018, LNCS, Springer,
including appendi
Retear of anterior cruciate ligament grafts in female basketball players: a case series
<p>Abstract</p> <p>Background</p> <p>Incidence of anterior cruciate ligament (ACL) injuries in young female basketball players is higher than that in male basketball players. Graft retears are more frequent with the increasing number of ACL reconstructions. The present study aimed to examine the incidence of retears in competitive female basketball players.</p> <p>Methods</p> <p>Sixty-four female basketball players (aged 12 to 29 years) who underwent primary anatomic double-bundle ACL reconstruction using hamstring grafts participated in the study. We investigated incidence, mechanism, and patient characteristics of ACL graft retears. Mann-Whitney <it>U </it>test was used for statistical analysis, and the level of significance was determined at <it>P </it>< 0.05.</p> <p>Results</p> <p>Six patients suffered from ACL graft retear (9.4%). Mean duration between primary ACL reconstruction and incidence of retears was 11.7 months. However, there were no other postoperative graft ruptures after 24 months. Primary injury and retear mechanisms varied by patient. At six months after the primary ACL reconstruction surgery, mean quadriceps and hamstring strengths were 81% and 87%, respectively, indicating favorable recovery of muscle strength. However, preoperative quadriceps and hamstring strength in the retear group were 65% and 71%, respectively. In particular, preoperative quadriceps strength in the retear group demonstrated a lower value than that in the uninjured group (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>We observed a high incidence of ACL graft retears in competitive female basketball players, as previously reported. Considering the timing of graft retear occurrences, an early return to playing basketball should be avoided following ACL reconstruction. Closer attention should be paid to player preoperative condition, as well as muscle strength and postoperative status.</p
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