Tris(3-nitro­pentane-2,4-dionato-κ2 O,O′)­cobalt(III)

The structure of the title compound, [Co(C5H6NO4)3], consists of a CoIII ion octahedrally coordinated by three bidentate 3-nitro­pentane-2,4-dionate ligands. The complex was prepared via the nitration of tris­(2,4-penta­nedionato-κ2 O,O′)cobalt(III) with a solution of copper(II) nitrate in glacial acetic acid. The central C atom and the nitro group of one 3-nitro­pentane-2,4-dionate ligand are disordered over two positions with an occupancy ratio of 0.848 (4):0.152 (4). A second nitro group is also disordered over two orientations with an occupancy ratio of 0.892 (7):0.108 (7). Two of the ligand methyl groups form C—H⋯O inter­actions with two different nitro groups to form chains running along the c axis. Additional C—H⋯O inter­actions are found between ligand methyl groups and the cobalt-bound O atoms, also resulting in the formation of chains along the c axis

Globally dispersed engineering teams at Delphi Packard Electric Systems

Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, February 2001.Includes bibliographical references (p. 135-136).Globally dispersed engineering teams within Delphi Packard Electric Systems were studied to identify areas for future improvement in global team performance. The research consisted of several management interviews and the administering of a survey to global team members and team leaders at various Delphi Packard Electric Systems engineering and manufacturing facilities located throughout the world. The results of the survey were analyzed using bivariate statistical analysis methods and suggestions for future improvement were developed based on the interviews and survey results. The suggestions were summarized as leadership leverage points for various levels of leadership within the company, including team leaders, regional (local) managers, and global managers. A system dynamics causal loop model was also developed to describe the relationships for various factors that affect team performance, including availability of capital (material resources), skills of the team members, individual and collective team effort, team interaction and communication, use of task-appropriate strategies, global versus local issues, and team results. The original survey was modified and expanded to allow future researchers to better address the variables and relationships that were presented in the casual loop system dynamics model.by Christopher D. Burns.S.M

Understanding Humanitarian Supply Chain Logistics with Systems Dynamics Modeling

Purpose – We explore the short-term humanitarian response to a natural disaster that prompts a rapid influx of relief supplies to the area affected by the disaster, aiming to understand the dynamics of systemic processes that apply to humanitarian supply chain logistics. Design/methodology/approach – We use system dynamics to simulate the disaster relief supply chain elements of humanitarian response. System dynamics is a well-established simulation method for analyzing complex social systems that include feedback. We used it because the timing and coordination of, and feedback loops among, events in humanitarian response incorporate a delay structure that can be modeled effectively using system dynamics. Findings – Of all the stocks in our model of the Humanitarian Stock Management System, the most important was the Cumulative Food distributed to disaster victims. In all of our simulation runs, victims eventually got all the food they needed, but at varying speeds (fast in the base run, slow in runs where repair of infrastructure was slow). However, the most problematic stock was the amount of Food in the Central Warehouse. In almost all the runs, that stock contained an excess of food (which is very common in such situations), resulting in waste and inefficiency. This problem was worst when the agency panicked at the outset and doubled its estimate of needed food, and when, as is often true, the agency received too many in-kind donations of food. The most interesting finding was that “managing” donations led to the best overall performance--low waste, good relief for victims. Practical implications – We offer a number of policy recommendations, including the need to avoid early bias, to repair infrastructure as quickly as possible, to develop better methods for keeping track of inventories and supplies on the way, and striking a balance between encouraging and dampening donations. Originality/value – This study focuses on understanding the short-term dynamics of the logistics of a humanitarian response, using a system dynamics approach. There have been only two other studies applying system dynamics to humanitarian assistance. One was operational and focused on long-term dynamics (often called “development,” as opposed to “response”) and the other was abstract and focused on those same longer-term dynamics. While these studies have produced meaningful insight, our study is unique in that we have applied an operational approach to a short, or “crisis response,” time horizon

Preservational bias controls the fossil record of pterosaurs

Pterosaurs, a Mesozoic group of flying archosaurs, have become a focal point for debates pertaining to the impact of sampling biases on our reading of the fossil record, as well as the utility of sampling proxies in palaeodiversity reconstructions. The completeness of the pterosaur fossil specimens themselves potentially provides additional information that is not captured in existing sampling proxies, and might shed new light on the group’s evolutionary history. Here we assess the quality of the pterosaur fossil record via a character completeness metric based on the number of phylogenetic characters that can be scored for all known skeletons of 172 valid species, with averaged completeness values calculated for each geological stage. The fossil record of pterosaurs is observed to be strongly influenced by the occurrence and distribution of Lagerstätten. Peaks in completeness correlate with Lagerstätten deposits, and a recovered correlation between completeness and observed diversity is rendered non-significant when Lagerstätten species are excluded. Intervals previously regarded as potential extinction events are shown to lack Lagerstätten and exhibit low completeness values: as such, the apparent low diversity in these intervals might be at least partly the result of poor fossil record quality. A positive correlation between temporal patterns in completeness of Cretaceous pterosaurs and birds further demonstrates the prominent role that Lagerstätten deposits have on the preservation of smaller bodied organisms, contrasting with a lack of correlation with the completeness of large-bodied sauropodomorphs. However, we unexpectedly find a strong correlation between sauropodomorph and pterosaur completeness within the Triassic–Jurassic, but not the Cretaceous, potentially relating to a shared shift in environmental preference and thus preservation style through time. This study highlights the importance of understanding the relationship between various taphonomic controls when correcting for sampling bias, and provides additional evidence for the prominent role of sampling on observed patterns in pterosaur macroevolution

DYNAMIC EVALUATION OF A PINNED ANCHORING SYSTEM FOR NEW YORK STATE’S TEMPORARY CONCRETE BARRIERS

Temporary concrete barrier (TCB) systems are utilized in many circumstances, including for placement adjacent to vertical dropoffs. Free-standing TCB systems are known to have relatively large deflections when impacted, which may be undesirable when dealing with limited space behind the barrier (as seen on a bridge deck) or limited lane width in front of the barrier system. In order to allow TCB systems to be used in space-restricted locations, a variety of TCB stiffening options have been tested, including beam stiffening and pinning the barriers to the pavement. These pavement-pinning procedures have been considered time-consuming and may pose undue risk to work-zone personnel who are anchoring the barrier on the traffic-side face. Thus, a means of reducing TCB deflections while reducing risk to workers was deemed necessary. The primary research objective was to evaluate the potential for pinning alternate barrier sections on the back-side toe of the New York State’s New Jersey-shape TCBs and evaluate the barrier system according to the Test Level 3 (TL-3) criteria set forth in MASH. The research study included one 2270P full-scale vehicle crash test with a Dodge Quad Cab pickup truck. Four 151⁄2-in. (394-mm) long, vertical steel pins were placed through holes on the back-side toe of alternating barrier sections and inserted into drilled holes within the rigid concrete surface. Following the successful redirection of the pickup truck, the safety performance of the pinned anchoring system was determined to be acceptable according to the TL-3 evaluation criteria specified in MASH using the 2270P vehicle. However, it should be noted that significant barrier deflections were observed during the crash test and may be greater than those desired for work areas with restricted space

Law, responsibility, and the brain.

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