7,101 research outputs found

    Forecasting Aggregate Period Specific Birth Rates: The Time Series Properties of a Microdynamic Neoclassical Model of Fertility

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    This article demonstrates the value of microdata for understanding the effect of wages on life cycle fertility dynamics. Conventional estimates of neoclassical economic fertility models obtained from linear aggregate time series regressions are widely criticized for being nonrobust when adjusted for serial correlation. Moreover, the forecasting power of these aggregative neoclassical models has been shown to be inferior when compared with conventional time series models that assign no role to wages. This article demonstrates, that when neoclassical models of fertility are estimated on microdata using methods that incorporate key demographic restrictions and when they are properly aggregated, they have considerable forecasting power.

    The Effect of Expected Income on Individual Migration Decisions

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    The paper develops a tractable econometric model of optimal migration, focusing on expected income as the main economic influence on migration. The model improves on previous work in two respects: it covers optimal sequences of location decisions (rather than a single once-for-all choice), and it allows for many alternative location choices. The model is estimated using panel data from the NLSY on white males with a high school education. Our main conclusion is that interstate migration decisions are influenced to a substantial extent by income prospects. The results suggest that the link between income and migration decisions is driven both by geographic differences in mean wages and by a tendency to move in search of a better locational match when the income realization in the current location is unfavorable.

    Taxation

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    The Third Birth in Sweden

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    Great Mining Camps of Canada 8. The Bathurst Mining Camp, New Brunswick, Part 2: Mining History and Contributions to Society

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    In the Bathurst Mining Camp (BMC), 12 of the 45 known massive sulphide deposits were mined between 1957 and 2013; one was mined for iron prior to 1950, whereas three others had development work but no production. Eleven of the deposits were mined for base metals for a total production of approximately 179 Mt, with an average grade of 3.12% Pb, 7.91% Zn, 0.47% Cu, and 93.9 g/t Ag. The other deposit was solely mined for gold, present in gossan above massive sulphide, producing approximately one million tonnes grading 1.79 g/t Au. Three of the 11 mined base-metal deposits also had a gossan cap, from which gold was extracted. In 2012, the value of production from the Bathurst Mining Camp exceeded 670millionandaccountedfor58percentoftotalmineralproductioninNewBrunswick.BasemetalproductionstartedintheBMCin1957fromdepositsatHeathSteeleMines,followedbyWedgein1962,BrunswickNo.12in1964,BrunswickNo.6in1965,Caribouin1970,MurrayBrook,StratmatBoundaryandStratmatN5in1989,CaptainNorthExtensionin1990,andlastly,HalfMileLakein2012.TheonlymineincontinuousproductionformostofthistimewasBrunswickNo.12.Duringits49yearlifetime(19642013),itproduced136,643,367tonnesoforegrading3.44670 million and accounted for 58 percent of total mineral production in New Brunswick.Base-metal production started in the BMC in 1957 from deposits at Heath Steele Mines, followed by Wedge in 1962, Brunswick No. 12 in 1964, Brunswick No. 6 in 1965, Caribou in 1970, Murray Brook, Stratmat Boundary and Stratmat N-5 in 1989, Captain North Extension in 1990, and lastly, Half Mile Lake in 2012. The only mine in continuous production for most of this time was Brunswick No. 12. During its 49-year lifetime (1964–2013), it produced 136,643,367 tonnes of ore grading 3.44% Pb, 8.74% Zn, 0.37% Cu, and 102.2 g/t Ag, making it one of the largest underground base-metal mines in the world.The BMC remains important to New Brunswick and Canada because of its contributions to economic development, environmental measures, infrastructure, mining innovations, and society in general. The economic value of metals recovered from Brunswick No. 12 alone, in today’s prices exceeds 46 billion. Adding to this figure is production from the other mines in the BMC, along with money injected into the local economy from annual exploration expenditures (100s of 1000speryear)over60years.SeveralenvironmentalmeasureswereinitiatedintheBMC,includingtherequirementtobecleanshavenandcarryaportablerespirator(nowappliedtoallminesinCanada);waystotreatacidminedrainageandthethiosaltproblemthatcomesfromthemillingprocess;andpioneeringstudiestodevelopandinstallstreamsideincubationboxesforAtlanticSalmoneggsintheNepisiguitRiver,whichboostedsurvivalratestoover901000s per year) over 60 years. Several environmental measures were initiated in the BMC, including the requirement to be clean shaven and carry a portable respirator (now applied to all mines in Canada); ways to treat acid mine drainage and the thiosalt problem that comes from the milling process; and pioneering studies to develop and install streamside-incubation boxes for Atlantic Salmon eggs in the Nepisiguit River, which boosted survival rates to over 90%. Regarding infrastructure, provincial highways 180 and 430 would not exist if not for the discovery of the BMC; nor would the lead smelter and deep-water port at Belledune. Mining innovations are too numerous to list in this summary, so the reader is referred to the main text. Regarding social effects, the new opportunities, new wealth, and training provided by the mineral industry dramatically changed the living standards and social fabric of northern New Brunswick. What had been a largely poor, rural society, mostly dependent upon the fishing and forestry industries, became a thriving modern community. Also, untold numbers of engineers, geologists, miners, and prospectors `cut their teeth’ in the BMC, and many of them have gone on to make their mark in other parts of Canada and the world.Dans le camp minier de Bathurst (CMB), 12 des 45 gisements de sulfures massifs connus ont été exploités entre 1957 et 2013; un de ces gisements a été exploité pour le fer avant 1950, tandis que trois autres étaient en développement mais pas en production. Onze gisements ont été exploités pour des métaux communs pour une production totale d'environ 179 Mt, avec une teneur moyenne de 3,12% Pb, 7,91% Zn, 0,47% Cu et 93,9 g/t Ag. L'autre gisement était uniquement exploité pour l'or, présent dans le gossan au-dessus du sulfure massif, produisant environ un million de tonnes titrant 1,79 g/t Au. Trois des 11 gisements de métaux communs exploités avaient également un gossan, d'où l'or était extrait. En 2012, la valeur de la production du camp minier de Bathurst dépassait 670 millions de dollars et représentait 58% de la production minérale totale au Nouveau-Brunswick.La production de métaux communs a commencé dans le CMB en 1957 à partir des gisements de Heath Steele Mines, suivie de Wedge en 1962, Brunswick no 12 en 1964, Brunswick no 6 en 1965, Caribou en 1970, Murray Brook, Stratmat Boundary et Stratmat N- 5 en 1989, Captain North Extension en 1990, et enfin Half Mile Lake en 2012. La seule mine en production continue pendant la majeure partie de cette période était Brunswick no 12. Au cours de sa durée de vie de 49 ans (1964–2013), elle a produit 136 643 367 tonnes de minerai titrant 3,44% Pb, 8,74% Zn, 0,37% Cu et 102,2 g/t Ag, ce qui en fait l'une des plus grandes mines souterraines de métaux communs au monde.Le CMB demeure important pour le Nouveau-Brunswick et le Canada en raison de sa contribution au développement économique, aux mesures environnementales, à l'infrastructure, aux innovations minières et à la société en général. La valeur économique des métaux récupérés du seul gisement Brunswick n° 12, aux prix d’aujourd’hui, dépasse 46 milliards de dollars. S'ajoute à ce chiffre la production des autres mines du CMB, ainsi que l'argent injecté dans l'économie locale par les dépenses d'exploration annuelles (des centaines à des milliers de par an) sur 60 ans. Plusieurs mesures environnementales ont été lancées dans le CMB, y compris l'exigence d'être rasé de près et de porter un respirateur portatif (maintenant appliqué à toutes les mines au Canada); les moyens de traitement des effluents miniers acides et le problème des thiosels qui proviennent du processus de broyage; et les études pionnières pour développer et installer des boîtes d'incubation en bord de rivière pour les œufs de saumon de l'Atlantique dans la rivière Nepisiguit, ce qui a fait passer les taux de survie à plus de 90%. En ce qui concerne les infrastructures, les routes provinciales 180 et 430 n'existeraient pas sans la découverte du CMB; la fonderie de plomb et le port en eau profonde de Belledune non plus. Les innovations minières sont trop nombreuses pour être énumérées dans ce résumé, le lecteur est donc renvoyé au texte principal. En ce qui concerne les effets sociaux, les nouvelles possibilités, la nouvelle richesse et la formation offertes par l'industrie minière ont radicalement changé le niveau de vie et le tissu social du nord du Nouveau-Brunswick. Ce qui avait été une société rurale en grande partie pauvre, principalement tributaire des industries de la pêche et de la sylviculture, est devenu une communauté moderne florissante. De plus, un nombre incalculable d’ingénieurs, de géologues, de mineurs et de prospecteurs «se sont fait les dents» au CMB, et bon nombre d’entre eux ont continué à faire leurs marques dans d’autres régions du Canada et du monde

    Transcriptional profiling of colicin-induced cell death of Escherichia coli MG1655 identifies potential mechanisms by which bacteriocins promote bacterial diversity

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    We report the transcriptional response of Escherichia coli MG1655 to damage induced by colicins E3 and E9, bacteriocins that kill cells through inactivation of the ribosome and degradation of chromosomal DNA, respectively. Colicin E9 strongly induced the LexA-regulated SOS response, while colicin E3 elicited a broad response that included the induction of cold shock genes, symptomatic of translational arrest. Colicin E3 also increased the transcription of cryptic prophage genes and other laterally acquired mobile elements. The transcriptional responses to both these toxins suggest mechanisms that may promote genetic diversity in E. coli populations, pointing to a more general role for colicins in adaptive bacterial physiology than has hitherto been realized
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