Stock assessment of protogynous fish: evaluating measures of spawning biomass used to estimate biological reference points

In stock assessments, recruitment is typically modeled as a function of females only. For protogynous stocks, however, disproportionate fishing on males increases the possibility of reduced fertilization rates. To incorporate the importance of males in protogynous stocks, assessment models have been used to predict recruitment not just from female spawning biomass (Sf), but also from that of males (Sm) or both sexes (Sb). We conducted a simulation study to evaluate the ability of these three measures to estimate biological reference points used in fishery management. Of the three, Sf provides best estimates if the potential for decreased fertilization is weak, whereas Sm is best only if the potential is very strong. In general, Sb estimates the true reference points most closely, which indicates that if the potential for decreased fertilization is moderate or unknown, Sb should be used in assessments of protogynous stocks. Moreover, for a broad range of scenarios, relative errors from Sf and Sb occur in opposite directions, indicating that estimates from these measures could be used to bound uncertainty

Noctilucent Clouds Seen from North America

Noctilucent clouds are tenuous ice clouds that form in the upper mesosphere over arctic and subarctic regions in the summer. Observations of the clouds made during 1988 and 1989 by the North American surveillance network NLC CAN AM are presented. Observing took place from 15 May to 15 August, except for arctic sites, which observed from 1 April to 30 April and 15 August to 15 September due to the Midnight Sun. The peak incidence of noctilucent clouds occurred in July during both years. Both positive and negative sightings, that latter determined by at least two readings under favourable conditions, are plotted on date-latitude graphs. An apparent northern migration of noctilucent clouds (NCL) with latitude as the season progresses was detected. Although an attempt was made to look for an apparent longitudinal drift, none was found. A detailed comparison of how NLC have behaved and changed in the past quarter century is examined using the NCL CAN AM data in conjunction with the 1964-65 data presented by Fogle (1966).Key words: noctilucent clouds, northem migration, longitudinal drift, comparisonMots clés: nuages noctulescents, déplacement vers le nord, dérive en longitude, comparaiso

Effects of Elevated H\u3csup\u3e+\u3c/sup\u3e And P\u3csub\u3ei\u3c/sub\u3e on The Contractile Mechanics of Skeletal Muscle Fibres From Young and Old Men: Implications for Muscle Fatigue in Humans

The present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole‐muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73–89 years, n = 6) compared to young men (20–29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7‐fold greater with age and strongly associated with reductions in the electrically‐evoked contractile properties. To test whether cross‐bridge mechanisms could explain age‐related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H+) (pH 6.2) and inorganic phosphate (Pi) (30 mm). The fatigue‐mimicking condition caused marked reductions in force, shortening velocity and power and inhibited the low‐ to high‐force state of the cross‐bridge cycle, confirming findings from non‐human studies that these ions act synergistically to impair cross‐bridge function. Other than severe age‐related atrophy of fast fibres (−55%), contractile function and the depressive effects of the fatigue‐mimicking condition did not differ in fibres from young and old men. The selective loss of fast myosin heavy chain II muscle was strongly associated with the age‐related decrease in isometric torque (r = 0.785) and power (r = 0.861). These data suggest that the age‐related loss in muscle strength and power are primarily determined by the atrophy of fast fibres, but the age‐related increased fatigability cannot be explained by an increased sensitivity of the cross‐bridge to H+ and Pi

The detection of tightly closed flaws by nondestructive testing (NDT) methods

Liquid penetrant, ultrasonic, eddy current and X-radiographic techniques were optimized and applied to the evaluation of 2219-T87 aluminum alloy test specimens in integrally stiffened panel, and weld panel configurations. Fatigue cracks in integrally stiffened panels, lack-of-fusion in weld panels, and fatigue cracks in weld panels were the flaw types used for evaluation. A 2319 aluminum alloy weld filler rod was used for all welding to produce the test specimens. Forty seven integrally stiffened panels containing a total of 146 fatigue cracks, ninety three lack-of-penetration (LOP) specimens containing a total of 239 LOP flaws, and one-hundred seventeen welded specimens containing a total of 293 fatigue cracks were evaluated. Nondestructive test detection reliability enhancement was evaluated during separate inspection sequences in the specimens in the 'as-machined or as-welded', post etched and post proof loaded conditions. Results of the nondestructive test evaluations were compared to the actual flaw size obtained by measurement of the fracture specimens after completing all inspection sequences. Inspection data were then analyzed to provide a statistical basis for determining the flaw detection reliability

Cost of inpatient rehabilitation care in the Department of Veterans Affairs

Abstract—We investigated the determinants of inpatient rehabilitation costs in the Department of Veterans Affairs (VA) and examined the relationship between length of stay (LOS) and discharge costs using data from VA and community rehabilitation hospitals. We estimated regression models to identify patient characteristics associated with specialized inpatient rehabilitation costs. VA data included 3,535 patients discharged from 63 facilities in fiscal year 2001. We compared VA costs to community rehabilitation hospitals using a sample from the Uniform Data System for Medical Rehabilitation of 190,112 patients discharged in 1999 from 697 facilities. LOS was a strong predictor of cost for VA and non-VA hospitals. Functional status, measured by Functional Independence Measure (FIM) scores at admission, was statistically significant but added little explanatory value after controlling for LOS. Although FIM scores were associated with LOS, FIM scores accounted for little variance in cost after controlling for LOS. These results are most applicable to researchers conducting cost-effectiveness analyses.average costs, billing, charges, cost, health economics, micro-cost methods, reimbursement, rehabilitation, VA, veterans

The Relationship Between Molecular Gas Tracers and Kennicutt-Schmidt Laws

We provide a model for how Kennicutt-Schmidt (KS) laws, which describe the correlation between star formation rate and gas surface or volume density, depend on the molecular line chosen to trace the gas. We show that, for lines that can be excited at low temperatures, the KS law depends on how the line critical density compares to the median density in a galaxy's star-forming molecular clouds. High critical density lines trace regions with similar physical properties across galaxy types, and this produces a linear correlation between line luminosity and star formation rate. Low critical density lines probe regions whose properties vary across galaxies, leading to a star formation rate that varies superlinearly with line luminosity. We show that a simple model in which molecular clouds are treated as isothermal and homogenous can quantitatively reproduce the observed correlations between galactic luminosities in far infrared and in the CO(1->0) and HCN(1->0) lines, and naturally explains why these correlations have different slopes. We predict that IR-line luminosity correlations should change slope for galaxies in which the median density is close to the line critical density. This prediction may be tested by observations of lines such as HCO^+(1->0) with intermediate critical densities, or by HCN(1->0) observations of intensely star-forming high redshift galaxies with very high densities. Recent observations by Gao et al. hint at just such a change in slope. We argue that deviations from linearity in the HCN(1->0)-IR correlation at high luminosity are consistent with the assumption of a constant star formation efficiency.Comment: Accepted to ApJ. 11 pages, 4 figures, emulateapj format. This version has some additional models exploring the effects of varying metallicity and temperature. The conclusions are unchange

Is there scope to discontinue non-essential medication in patients with advanced lung cancer?

Focal Points 1. Patients with advanced lung cancer take many ‘non-essential’ medicines 2. A simple audit tool could be used to identify ‘non-essential’ medicines that could be discontinued 3. Pharmacists have a potential role in identifying and reviewing ‘non-essential’ medicines Background Lung cancer patients can present with complex medical histories often taking medications to manage existing conditions and prevent future morbidity e.g. antihypertensives and antiplatelets. Guidelines for discontinuing these medications in life-limiting illnesses, such as advanced lung cancer, have not been produced despite the potential to reduce burden, in terms of cost and, more importantly, discomfort to the patient.1 The objectives of this work was to audit the number of medications in patients taking erlotinib for the treatment of advanced lung cancer; and, develop a draft tool that can be used to identify non-essential medications which could, potentially, be discontinued. Methods This clinical audit was undertaken at an acute NHS Trust in April 2011. A clinical audit tool was used to extract data from medical notes of patients receiving erlotinib for non-small cell lung cancer (NSCLC) and compared to a set of criteria to establish if the medicine is essential, non-essential or uncertain. These criteria were based on a study that defined unnecessary medication as where there is no anticipated short-term benefit to patients with respect to survival, quality of life or symptom control.2 All patients who had received erlotinib in the Trust for the treatment of NSCLC within 18 months were selected for the audit. A consensus group (consultant pharmacist, lung nurse specialist and consultant oncologist) reviewed results and considered which medications they would have stopped. Results Of the 20 patients audited, 19 were taking at least one medication that could have been discontinued. The mean number of medications taken was 8 (range 1–16). Seventeen patients were taking essential medications (e.g. analgesics) necessary for symptom control in cancer. Non-essential medicines were regarded as those which provided no short term benefit to the patients with respect to survival, quality of life or symptom control or any medicine which had potential to cause harm. The focus group concurred that the majority of non-essential medications identified by the criteria could have been discontinued. Medications classified as uncertain were taken by 7 patients. These medications need to be further reviewed. Discussion For patients undergoing treatment for terminal lung cancer the issue of discontinuing medications is not an immediate priority. However, at some point in their treatment pathway a discussion regarding their medications should be instigated. The focus group revealed that timing of this discussion is crucial. The futile use of medication in terminally ill cancer patients has been reported in the literature and this work is in agreement with this by showing that patients with NSCLC taking erlotinib are taking unnecessary medications.2 Patients take medications such as statins and antihypertensives with the belief that they will be taking them for the rest of their lives, therefore if an appropriate explanation for discontinuation is not given the patients and/or their families may misconceive this as a death-hastening intervention. This work also showed that a significant number of patients who are taking erlotinib also take a proton pump inhibitor (PPI) despite the fact there is a clinically significant drug interaction between erlotinib and PPIs where the absorption of erlotinib is reduced.3 In conclusion, patients taking erlotinib for the treatment of advanced NSCLC take many unnecessary medications and written guidelines on what can be withdrawn are needed. There is the potential for pharmacists to become involved in the review of patients with terminal cancer to facilitate discontinuing potentially unnecessary medicines

Prospering through Prospera: CCT Impacts on Educational Attainment and Achievement in Mexico

This paper develops and estimates a dynamic model of student enrollment, school choice, academic achievement and grade progression to evaluate the impacts of Mexico’s conditional cash transfer program Prospera on educational outcomes over grades 4-9. Academic achievement is measured by nationwide standardized test scores in mathematics and Spanish. Enrollment decisions are the outcomes of sequential decisions at each age from individuals’ feasible choice sets, determined by the types of schools locally available and local-labor-market opportunities. The achievement production function has a value-added structure. Model parameters are estimated by maximum likelihood using nationwide administrative test-score data (the ENCEL data) combined with survey data from students and parents, census labor-market data, and geo-coded school-location data. The estimation approach controls for selective school enrollment in different types of schools, grade retention and unobserved heterogeneity. The results show that the Prospera program increases school enrollment and academic achievement for program beneficiaries in lower-secondary school grades (grades 7-9). The average test-score impacts are 0.09-0.13 standard deviations in mathematics and 0.03-0.05 standard deviations in Spanish. Students from the most disadvantaged backgrounds experience the largest impacts. The availability of telesecondary distance-learning schools is shown to be an important determinant of the Prospera program’s impacts on educational outcomes

Does Chemical Leaf Burn of Double Crop Soybeans Reduce Yield?

Most farmers who have applied acifluorfen (sold as Blazer or Tackle) for postemergence control of broadleaf weeds in soybean fields are aware that leaf crinkling, bronzing, and necrosis can result. Despite this, studies in Kentucky, Illinois, Arkansas, and South Carolina have shown that full season soybeans have plenty of time to recover from leaf burn caused by this herbicide, and no yield losses have been found. However, double crop soybeans are usually planted much later than the full season crop. This delay in planting may reduce the time for plants to complete vegetative growth before beginning the seed production process. Therefore, double crop soybeans may be limited in their ability to recover from acifluorfen injury in time to produce as much grain as nonsprayed soybeans. Our objective was to determine if yields of double crop soybeans are reduced by leaf burn due to the use of acifluorfen