Labor Market Density and Increasing Returns to Scale: How Strong is the Evidence?

Models of economic geography posit that the density of economic activity has two e¤ects that oppose each other in equilibrium: decreasing returns to productive activities due to congestion e¤ects and increasing returns that result from information spillovers and local demand externalities. In an in�uential paper, Ciccone and Hall (1996) looked at the effect of county level labor market concentration on per-worker Gross State Product in a cross section of US States, and observed that on net, the increasing returns/agglomeration effect dominates. We extend their analysis and re-examine the relationship between density and productivity across industries and over both states and time. Through careful identi�cation of the source and nature of productivity shocks, we show that the evidence for agglomeration effects is indeed quite robust, even within industries, providing evidence for the presence of Marshallian externalities. As for the balance of agglomeration and congestion e¤ects found in previous literature, what we call �net increasing returns to scale", the evidence is much weaker.

The rabbit : an illustrated anatomical guide

This study on the anatomy of the rabbit was based on dissected material from the biological laboratories of the College of the Pacific. Because of existing errors in many of the present references to rabbit anatomy, the guide was prepared to meet the expressed need for a concise, illustrated outline of basic anatomy of the rabbit which might be used by students in an introductory course in mammalian or human anatomy. Since it is assumed that the guide would be supplemented by a dissection manual, syllabus, or textbook, textural material of such an outline is presented here in outline form

The reliability of retrospective methods for exploring onset of height fear : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Psychology at Massey University, Palmerston North, New Zealand

The non-associative framework on fear argues that evolutionary-relevant fears, such as heights and water, are largely innate and do not require associative conditioning experiences to develop (Menzies & Clarke, 1993a, b; Poulton & Menzies, 2002a). However, this framework has been criticized for its reliance on retrospective recall for empirical support (Mineka & Öhman, 2002), which has been found to be highly unreliable (Taylor, Deane, & Podd, 1999). Thirty height-fearful undergraduate students completed the Origins Questionnaire-II (OQ-II; Menzies & Parker, 2001) and were classified into one of the several associative and non-associative pathways of fear onset based on their responses. A control group of 43 non-fearful students completed a modified version of the OQ-II to report any past experiences with heights. To examine the stability of these responses over time, the same questionnaires for both groups were completed again three months (Time 2) and 12 months (Time 3) after the initial administration of the test, along with measures of fear severity. Results showed that neither associative nor non-associative accounts took precedence over the other in explaining the onset of height fear. Instabilities in pathway ascriptions were observed in 18.18% of cases over three months (between Time 1 and Time 2), and 27.27% of cases over nine months (between Time 2 and Time 3). The theoretical and practical implications of the results are discussed with consideration of some of the study’s procedural and instrumental limitations. In light of these limitations, this study identified a substantial role of non-associative pathways on the development of height fear, and provided further support for the limitations of retrospective recall for ascertaining the pathway to fear onset

A Study of Weld Seams on Low Carbon Steel ABS Grade a Marine Plates Using SMAW Process

The research aims to study and assess the impact of weld seams of low carbon steel ABS Grade A marine plates of 12.7mm thick using manual SMAW process as per AWS D1.1 structural welding code requirements and fulfilments of ASME Section IX pressurized equipment welding code requirements too. Different voltages, currents, and travel speeds were used to weld the test specimen plates. After the manual SMAW process, a series of testing techniques, including non-destructive tests, such as VT and RT, and destructive tests, such as tensile tests, bend tests, impact tests, microhardness tests, and metallographic examination has been conducted to assess/evaluate on the welded seam profiles and analyses/determines whether the accepted welded seam profiles have fulfilled the relevant welding code requirements. From the series of assessments and analyses, it is confirmed that the welded test specimen 1 having the welding parameters (i.e., voltage 23 V, current 70 A, and travel speeds 56.52 – 312.50 mm/min, having a range of heat inputs from 0.31kJ/mm to 1.71kJ/mm) is accepted as the quality good weld seam

Carbon nanotube bumps for the flip chip packaging system

Carbon nanotube [CNT] interconnection bump joining methodology has been successfully demonstrated using flip chip test structures with bump pitches smaller than 150 μm. In this study, plasma-enhanced chemical vapor deposition approach is used to grow the CNT bumps onto the Au metallization lines. The CNT bumps on the die substrate are then 'inserted' into the CNT bumps on the carrier substrate to form the electrical connections (interconnection bumps) between each other. The mechanical strength and the concept of reworkable capabilities of the CNT interconnection bumps are investigated. Preliminary electrical characteristics show a linear relationship between current and voltage, suggesting that ohmic contacts are attained

The CYP2C19*1/*2 Genotype Does Not Adequately Predict Clopidogrel Response in Healthy Malaysian Volunteers

Background. The CYP2C19*2 allele may be associated with a reduced antiplatelet effect for clopidogrel. Here, we assessed whether CYP2C19*2 alleles correlate with clopidogrel responsiveness following the administration of clopidogrel in healthy Malaysian volunteers. Methods. Ninety volunteers were genotyped for CYP2C19*2 and CYP2C19*3 alleles. Forty-five of 90 volunteers were included in the clopidogrel response studies and triaged into three genotypes, namely, CYP2C19*1/*1 (n=17), CYP2C19*1/*2 (n=21), and CYP2C19*2/*2 (n=7). All subjects received 300 mg of clopidogrel, and platelet reactivity was assessed after a four-hour loading utilizing the VerifyNow-P2Y12 assay. Platelet activity was reported using P2Y12 reaction units (PRUs), and nonresponder status was prespecified at PRU ≥ 230. Results. Following clopidogrel intake, CYP2C19*2/*2 carriers had a significantly higher mean PRU compared to the CYP2C19*1/*2 and CYP2C19*1/*1 (291.0 ± 62.1 versus 232.5 ± 81.4 versus 147.4 ± 87.2 PRU, P<0.001) carriers. Almost half of the participants (46.7%) were found to be nonresponders (3 were CYP2C19*1/*1, 11 were CYP2C19*1/*2, and 7 were CYP2C19*2/*2). Conclusion. In healthy Malaysian volunteers, CYP2C19*2 allele was associated with a decrease in platelet responsiveness to clopidogrel. However, clopidogrel nonresponders can be found not only in the carriers of CYP2C19*2/*2, but also in the carriers of CYP2C19*1/*2 and CYP2C19*1/*1. The present paper demonstrated that genotype information does not correlate with clopidogrel response, and genotyping may represent a less robust approach compared to platelet activity testing in guiding clopidogrel therapy

Progression of Hypertrophy and Myocardial Fibrosis in Aortic Stenosis: A Multicenter Cardiac Magnetic Resonance Study

Background: Aortic stenosis is accompanied by progressive left ventricular hypertrophy and fibrosis. We investigated the natural history of these processes in asymptomatic patients and their potential reversal post-aortic valve replacement (AVR).  Methods: Asymptomatic and symptomatic patients with aortic stenosis underwent repeat echocardiography and magnetic resonance imaging. Changes in peak aortic-jet velocity, left ventricular mass index, diffuse fibrosis (indexed extracellular volume), and replacement fibrosis (late gadolinium enhancement [LGE]) were quantified.  RESULTS: In 61 asymptomatic patients (43% mild, 34% moderate, and 23% severe aortic stenosis), significant increases in peak aortic-jet velocity, left ventricular mass index, indexed extracellular volume, and LGE mass were observed after 2.1±0.7 years, with the most rapid progression observed in patients with most severe stenosis. Patients with baseline midwall LGE (n=16 [26%]; LGE mass, 2.5 g [0.8–4.8 g]) demonstrated particularly rapid increases in scar burden (78% [50%–158%] increase in LGE mass per year). In 38 symptomatic patients (age, 66±8 years; 76% men) who underwent AVR, there was a 19% (11%–25%) reduction in left ventricular mass index (P<0.0001) and an 11% (4%–16%) reduction in indexed extracellular volume (P=0.003) 0.9±0.3 years after surgery. By contrast midwall LGE (n=10 [26%]; mass, 3.3 g [2.6–8.0 g]) did not change post-AVR (n=10; 3.5 g [2.1–8.0 g]; P=0.23), with no evidence of regression even out to 2 years.  Conclusions: In patients with aortic stenosis, cellular hypertrophy and diffuse fibrosis progress in a rapid and balanced manner but are reversible after AVR. Once established, midwall LGE also accumulates rapidly but is irreversible post valve replacement. Given its adverse long-term prognosis, prompt AVR when midwall LGE is first identified may improve clinical outcomes

An assessment of how bio-E10 will impact the vehicle-related ozone contamination in China

Bio-E10 is short for the biofuel made up of 90% gasoline in volume and 10% bio-ethanol, which is the ethanol made from commercially-grown crops such as corn and wheat by the sugar fermentation process. In China, bio-E10 will be supplied nationwide from 2020 as an alternative to conventional gasoline, aiming at ensuring greater energy security and lowering the greenhouse gas emissions. In order to assess the impacts of the upcoming bio-E10 application on the ozone forming potential (OFP) of the emissions from in-use vehicles, this paper examined the carbonyls and volatile organic compounds (VOCs) in the evaporative and tailpipe emissions of three China-4 certified in-use vehicles fueled with a market-available gasoline and two match-blend bio-E10s, and calculated their OFPs using the Maximum Incremental Reactivity (MIR) method. The results revealed that for the evaporative emissions, the use of bio-E10s increased the carbonyl and VOC emissions released within the diurnal-loss stage by 8.5–17.6% and 11.1–78.6% respectively, but decreased the carbonyl and VOC emissions in the hot-soak stage by 47.4%–61.5% and 4.8%–20.6% respectively. Regarding the tailpipe emissions, in comparison to the gasoline baseline, burning bio-E10s increased the carbonyls by 15%–46% while reducing the VOCs by 37%–56% over the New European Driving Cycle (NEDC). Reductions in the tailpipe OFPs up to 47.3% were seen with the application of the bio-E10s, however, there were no clear conclusions with respect to the evaporative OFPs, which varied from −15% to ＋25% compared to the gasoline baseline. Based on the test results and census data, the application of bio-E10 in China is shown to help remove part of ozone contamination from the in-use vehicle sector

Variant Alleles in XRCC1 Arg194Trp and Arg399Gln Polymorphisms Increase Risk of Gastrointestinal Cancer in Sabah, North Borneo

Background: The XRCC1 protein facilitates various DNA repair pathways; single-nucleotide polymorphisms (SNPs) in this gene are associated with a risk of gastrointestinal cancer (GIC) with inconsistent results, but no data have been previously reported for the Sabah, North Borneo, population. We accordingly investigated the XRCC1 Arg194Trp and Arg399Gln SNPs in terms of GIC risk in Sabah. Materials and Methods: We performed genotyping for both SNPs for 250 GIC patients and 572 healthy volunteers using a polymerase chain reaction-restriction fragment length polymorphism approach. We validated heterozygosity and homozygosity for both SNPs using direct sequencing. Results: The presence of a variant 194Trp allele in the Arg194Trp SNP was significantly associated with a higher risk of GIC, especially with gastric and colorectal cancers. We additionally found that the variant 399Gln allele in Arg399Gln SNP was associated with a greater risk of developing gastric cancer. Our combined analysis revealed that inheritance of variant alleles in both SNPs increased the GIC risk in Sabah population. Based on our etiological analysis, we found that subjects ≥50years≥50yearsand males who carrying the variant 194Trp allele, and Bajau subjects carrying the 399Gln allele had a significantly increased risk of GIC. Conclusions: Our findings suggest that inheritance of variant alleles in XRCC1 Arg194Trp and Arg399Gln SNPs may act as biomarkers for the early detection of GIC, especially for gastric and colorectal cancers in the Sabah population