Exploring the application of machine learning to the assembly line feeding problem

As a large number of companies are resorting to increased product variety and customization, a growing attention is being put on the design and management of part feeding systems. Recent works have proved the effectiveness of hybrid feeding policies, which consist in using multiple feeding policies in the same assembly system. In this context, the assembly line feeding problem (ALFP) refers to the selection of a suitable feeding policy for each part. In literature, the ALFP is addressed either by developing optimization models or by categorizing the parts and assigning these categories to policies based on some characteristics of both the parts and the assembly system. This paper presents a new approach for selecting a suitable feeding policy for each part, based on supervised machine learning. The developed approach is applied to an industrial case and its performance is compared with the one resulting from an optimization approach. The application to the industrial case allows deepening the existing trade-off between efficiency (i.e., amount of data to be collected and dedicated resources) and quality of the ALFP solution (i.e., closeness to the optimal solution), discussing the managerial implications of different ALFP solution approaches and showing the potential value stemming from machine learning application.

Techniques of Onyx Embolization of Arteriovenous Malformation: 2-Dimensional Operative Video

Advances in endovascular techniques and tools have allowed for treatment of complex arteriovenous malformations (AVMs), which historically may have posed unacceptable risk for open surgical resection. Endovascular treatment may be employed as an adjunct to surgical resection or as definitive therapy. Improvements in embolization materials have made endovascular AVM treatment safer for patients and useful across a variety of lesions. While many techniques are employed for transarterial AVM embolization, the essential tenets apply to all procedures: (1) great care should be taken to cannulate only vessels directly supplying the lesion, and not en passage vessels, prior to injecting embolisate; (2) embolisate should travel into the nidus, but not into the draining veins; (3) embolistate reflux proximal to the microcatheter should be avoided. There are several techniques that accomplish these goals, including the plug and push method, or using a balloon to prevent embolisate reflux. We use controlled injection of liquid Onyx (Medtronic), with increasing pressure over multiple injections pushing the embolisate forward into the AVM. This is repeated in multiple feeding vessels to decrease or eliminate supply to the AVM. Here, we present a 36-yr-old female with a right parietal AVM discovered on workup of headaches. After informed consent was obtained, she underwent preoperative embolization using this technique prior to uncomplicated surgical resection. The video shows the endovascular Onyx embolization of multiple feeding vessels over staged treatment.

Complex Tidal Marsh Dynamics Structure Fish Foraging Patterns in the San Francisco Estuary

Mechanisms driving the consumption and transport of tidal marsh nutrients and energy by fishes are of key interest in the San Francisco Estuary, CA, USA. By combining multiple data sources (gill-net catches, gut contents, channel morphology, tides), we modeled spatial and temporal patterns of fish abundance and gut fullness across a tidal marsh elevation gradient. Channel depth, microhabitat, and tide were important predictors of fish abundance and gut fullness. Species, feeding guild, and season were also important to fish abundance but not to gut fullness, suggesting that abundance was more related to physical constraints of shallow water than to prey availability. Multiple feeding guilds overlapped in space and time at interaction hotspots in subtidal channel habitat near the marsh entrance. In contrast, fish use of shallow intertidal marsh channels was more variable and indicated tradeoffs between foraging and predation. Gut content analysis revealed moderate-to-high gut fullness for all feeding guilds and models predicted high gut fullness in subtidal reaches during tidal flooding, after which fish fed intensively throughout the marsh. While mysids, amphipods, and detritus were common prey among feeding guilds, variation in prey consumption was apparent. Overall, complex tidal marsh hydrogeomorphology driving land-water exchange and residence time may diversify and enhance benthic and pelagic food web pathways to fishes and invertebrates. Furthermore, these findings substantiate the notion that dynamic tidal marshes in this system can support robust secondary production, foraging by multiple feeding guilds, and trophic transfer by fishes to the estuarine mosaic.

A review of the non-indigenous Chinese Mystery Snail, Cipangopaludina chinensis (Viviparidae), in North America, with emphasis on occurrence in Canada and the potential impact on indigenous aquatic species

Evidence suggests that the Chinese mystery snail, Cipangopaludina chinensis, a freshwater, dioecious, snail of Asian origin has become invasive in North America, Belgium, and the Netherlands. Invasive species threaten indigenous biodiversity and have socioeconomic consequences where invasive. The aim of this review is to synthesize the relevant literature pertaining to C. chinensis in Canada. In doing so, we (1) describe C. chinensis ecosystem interactions in both indigenous (Asian) and non-indigenous habitats (North America and Europe), (2) identify gaps in the literature, and (3) determine where the species potential distribution in North America requires further exploration. We also briefly discuss potential management strategies for this species, as an aquatic invasive species (AIS), in Canada. Due to the much larger relative size of adult C. chinensis, multiple feeding mechanisms, and resistance to predation, C. chinensis can out-compete and displace indigenous freshwater gastropods and other molluscs. Furthermore, C. chinensis can affect food webs through bottom-up interactions with the bacterial and zooplankton communities by changing nitrogen and phosphorous concentrations. Also, the Chinese literature indicates the potential for C. chinensis to act as a biotransfer of contaminants between polluted ecosystems and consumers. In its indigenous range, C. chinensis was identified as a host for numerous parasites harmful to human and animal consumers alike. A comparison of the Canadian geographical distribution of reported occurrences with that for the United States indicates several potential gaps in Canadian reporting which merits further investigation and consideration, especially in regard to federal and provincial non-indigenous monitoring and regulations. Southern Ontario had the highest number of reports which were mostly from web-based photo-supported sources. This suggests that interactive citizen science through popular apps backed by well-supported educational campaigns may be a highly effective means of tracking C. chinensis spread, which can be complementary to traditional methods using specimen-vouchered taxonomically-verified natural-history collections overseen by professional curators.

Using phosphate to increase feeding consumption in termite Coptotermes formosanus

Termites are ecologically significant in positive and negative ways; their role in breaking down debris greatly benefits forest environments, but this activity renders them a pest in domestic environments. This study examines the effect of nutrition on the feeding preference of termite Coptotermes formosanus Shiraki. Among 11 nutrition options tested, dipotassium phosphate (DKP) most significantly increased feeding consumption in the multiple feeding choice test. The mean feeding amount of the DKP-treated sample was 2.5-fold higher than that of the deionized water-treated control. This result suggests that termite colonies are deficient in phosphorus, and an additional supply of phosphate can promote feeding. The result of a no-choice feeding test using DKP shows that DKP does not promote feeding in a small number of termites. The results obtained in this study suggest that phosphorus is needed in termite colonies, making DKP especially effective. DKP will help to improve bait technology, because it is inexpensive and safe for both humans and the environment.

Not all nudibranchs are carnivorous: trophic ecology of Polycerella emertoni in the Ebro Delta

Nudibranchs have always been regarded as a group of specialized predators. In Alfacs Bay (Ebro Delta, Spain), the cryptic nudibranch Polycerella emertoni is found associated with the pseudo-indigenous bryozoan Amathia verticillata, which has been thought to be its target prey. Here, we assessed the trophic ecology of P. emertoni using a combination of methods, including stable isotope analyses coupled with Bayesian mixing models, examination of stomach contents, and video recording of feeding activities. A morphological analysis of the radula was also conducted to explore a possible relationship with feeding behavior. Finally, we investigated the seasonal abundance of both species throughout an entire year in order to assess the nature and strength of their association. Contrary to current belief, our results show that P. emertoni is a micro-herbivore that feeds on the periphyton covering A. verticillata (up to 99% of the diet, according to mixing models). In particular, a diverse diatom community was observed on A. verticillata, and several of these taxa were found within the stomach contents of P. emertoni. Our results evidence a distinctive radular formula and morphology compared to other species and suggest the presence of multiple feeding strategies in nudibranchs. The high seasonal association observed between P. emertoni and A. verticillata may be attributed to mimicking habitat features as a mechanism to avoid predation. The possible effects of periphyton removal in the survival of detached fragments of A. verticillata may have implications for the dispersal of fouling species and functioning of ecosystems.

Thoracic 11-Lumbar 1 Laminoplasty for Resection of Conus Arteriovenous Malformation: 2-Dimensional Operative Video

Conus medullaris spinal arteriovenous malformations are uniquely classified by the Spetzler classification. They possess a glomus (type II) nidus in either or both the intra- and extramedullary compartments, with multiple feeding arteries and niduses resulting in complex venous drainage patterns. These characteristics make resection of these lesions challenging, and these lesions are associated with a high risk for recurrence. This patient presented with a subarachnoid hemorrhage, and thorough imaging evaluation revealed a conus arteriovenous malformation. The patient underwent thoracic 11 to lumbar 1 laminoplasty for resection of the lesion. The arteriovenous malformation was circumdissected off the conus and lumbosacral nerve roots using sharp dissection and bipolar forceps. It was visualized both before and after resection with indocyanine green fluoroscopy. The patient tolerated the procedure well, and postoperative angiography demonstrated complete resection. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.