Space,Time, and Local Employment Growth: An Application of Spatial Regression Analysis

ABSTRACT Local and regional employment growth is generally studied either by searching for local qualitative explanatory factors such as governance, synergy between firms, and milieu effects, or by searching for general growth factors using statistical techniques. The body of work that relies on this approach has tended, in keeping with economics’ nomothetic tradition, to assume that local and regional growth factors are constant over space. The focus of this paper is on exploring the spatial stationarity of employment growth factors in Canada, but it also seeks to clarify some of the broad principles behind spatial regression techniques in order to provide a point of entry and a conceptual framework for empirical researchers. To do so, we apply a recently developed technique, Geographically Weighted Regression (GWR), and we explore the method's advantages and limits for answering our research question. We find evidence that growth factors differ across Canada, but we also conclude that the GWR technique, given the number and shape of regions available for our analysis and given certain limitations that are currently inherent to the method, can only provide tentative and exploratory results.     

IMAGING DIAGNOSIS—INTRAPERICARDIAL RIGHT AURICLE ANEURYSM IN A DOG

An 11‐year‐old, male, Pekinese was examined because of a sporadic, nonresponsive, nonproductive cough. Radiographically there was cardiomegaly and a soft tissue mass in the cranial mediastinum. Echocardiographically, chronic degenerative valvular disease was diagnosed. Furthermore, a large anechoic structure located cranial to the right atrium was detected. Computed tomography was performed to define the mediastinal mass and a right auricle aneurysm was diagnosed. The dog died suddenly 1 day after the diagnostic imaging procedures. At necropsy, a right auricular aneurysm without discontinuity of the pericardial sac was confirmed. Intrapericardial right auricular aneurysm should be included in the differential diagnoses of cranial mediastinal masses.     

LAPAROSCOPIC ULTRASONOGRAPHY IN SIX DOGS

The aim of this study was to describe the technique of laparoscopic ultrasonography in six dogs with intra-abdominal disease. Investigation of the abdominal cavity was undertaken initially in each dog by laparoscopy alone. After exploration and visualization of a diseased organ, a 7.5 MHz microconvex ultrasound probe was introduced into the abdomen through a laparoscopic cannula for videoguided ultrasound examination. Laparoscopic ultrasonography allows core biopsy or needle aspiration to be performed by guiding the needle into nonsuperficial lesions, where videoendoscopic guidance alone is not enough. In addition, color Doppler ultrasonography is useful to examine the vascular pattern to minimize or eliminate complications when a biopsy is performed.     

Distribution and abundance of two species of codlet (Teleostei, Bregmacerotidae) larvae from the south-eastern Brazilian Bight

Two species of codlet (Bregmacerotidae) larvae were collected during nine survey cruises conducted in the south-eastern Brazilian Bight between 23^oS and 30^oS in 1985-91. Of 4846 codlet larvae collected during nine cruises, 99.2% were identified as Bregmaceros canton and only 0.8% were B. athanticus. The two species were more abundant during winter in the neritic region (60–135 m depth). Vertical distribution of codlet larvae was studied using the BIOMOC net, and vertical profiles of temperature/salinity and chlorophyll a concentration were recorded by CTD and fluorescent sonde. Only 9.0% of larvae were collected in the upper 30 m and 91.0% were found deeper (> 40 m). The depths of highest density of larvae bore a close relationship to the subsurface chlorophyll maximum layer. Some B. canton larvae were found in the upper 30 m layer at night, but no larva was found during the day. Water temperatures where B. canton larvae occurred ranged from 16 to 23^oC, but most larvae were found at 18–20^oC and in salinities of 35.5–36.5 psu.     

CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE SMALL BOWEL IN HEALTHY CATS

We characterized the pattern of ultrasonographic contrast enhancement of the small intestinal wall using a commercial contrast medium (Sonovue^®) in 10 healthy awake cats. Subjectively, a rapid intense enhancement of the serosal and submucosal layers was followed by gradual enhancement of the entire wall section during the early phase. At peak enhancement, there was a subjective loss of demarcation between intestinal wall layers. In the late phase, there was a gradual wash out of signal from the intestinal wall. Submucosal wash out occurred last. Time‐intensity curves were generated for selected regions in the intestinal wall and multiple perfusion parameters were calculated for each cat. Perfusion parameters included arrival time (7.64 ± 2.23 s), baseline intensity (1.04 ± 0.04 a.u.), time to peak from injection (10.74 ± 2.08 s), time to peak from initial rise (3.1 ± 1.15), peak intensity (8.92 ± 3.72 a.u.), wash‐in rate (2.06 ± 0.70 a.u./s) and wash‐out rate (?1.07 ± 0.91 a.u./s). The perfusion pattern of normal feline small bowel may be useful for characterizing feline gastrointestinal disorders that involve the intestinal wall.     

Spatial correspondence between areas of concentration of Patagonian scallop (Zygochlamys patagonica) and frontal systems in the southwestern Atlantic

It has been hypothesized that the geographical location of scallop beds in extensive shelf regions mirrors hydrographic structures (e.g. frontal systems) that favor the retention/concentration of pelagic larvae. Large, discontinuous concentrations of the Patagonian scallop (Zygochlamys patagonica) are known to have occurred recurrently (for more than 30 yr) at certain geographical locations over the extensive Patagonian shelf. These stocks, exploited since 1996, currently support one of the most important scallop fisheries in the world. Here, we investigate whether those aggregations are spatially coincidental with major frontal systems. Several pieces of information were used: historical survey data documenting the geographic distribution of the Patagonian scallop beds, catch and effort data from the commercial fleet, oceanographic data on frontal systems, and remote sensing imagery. We found that large-scale aggregations do match the location of three major and very different frontal systems in the southwestern Atlantic: the Shelf-Break Frontal System, the Northern Patagonia Frontal System, and the Southern Patagonia Frontal System. We describe the three frontal systems and their associated scallops fishing grounds and discuss which processes can contribute to sustaining the productivity of the scallop grounds in each case.     

IMAGING DIAGNOSIS—ULTRASONOGRAPHIC DIAGNOSIS OF DIPLOMYELIA IN A CALF

We describe the ultrasonographic diagnosis of diplomyelia in a 40‐day‐old calf. The acoustic window was the lumbosacral junction, which, in cattle, corresponds to the L6–S1 intervertebral space and enables the evaluation of approximately 1 cm of the length of the spinal cord. Despite this limited length, this acoustic window yields good anatomic details and can be helpful in assessing anomalies of the caudal aspect of the spinal cord.     

Growth and Location of Economic Activity: The Spatial Dynamics of Industries in Canada 1971–2001

ABSTRACT A growing literature has accumulated that points to the stability of industrial location patterns. Can this be reconciled with spatial dynamics? This article starts with the premise that demonstrable regularities exist in the manner in which individual industries locate (and relocate) over space. For Canada, spatial distributions of employment are examined for seventy‐one industries over a thirty‐year period (1971–2001). Industry data is organized by “synthetic regions” based on urban size and distance criteria. “Typical” location patterns are identified for industry groupings. Industrial spatial concentrations are then compared over time using correlation analysis, showing a high degree of stability. Stable industrial location patterns are not, the article finds, incompatible with differential regional growth. Five spatial processes are identified, driving change. The chief driving force is the propensity of dynamic industries to start up in large metro areas, setting off a process of diffusion (for services) and crowding out (for manufacturing), offset by the centralizing impact of greater consumer mobility and falling transport costs. These changes do not, however, significantly alter the relative spatial distribution of most industries over time.