Delegation Proxies: The Power of Propagation

Scoping behavioral variations to dynamic extents is useful to support non-functional requirements that otherwise result in cross-cutting code. Unfortunately, such variations are difficult to achieve with traditional reflection or aspects. We show that with a modification of dynamic proxies, called delegation proxies, it becomes possible to reflectively implement variations that propagate to all objects accessed in the dynamic extent of a message send. We demonstrate our approach with examples of variations scoped to dynamic extents that help simplify code related to safety, reliability, and monitoring.

Worldwide evidence of a unimodal relationship between productivity and plant species richness

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity.

Critical point and scale setting in SU(3) plasma: An update

We explore a method developed in statistical physics which has been argued to have exponentially small finite-volume effects, in order to determine the critical temperature Tc of pure SU(3) gauge theory close to the continuum limit. The method allows us to estimate the critical coupling βc of the Wilson action for temporal extents up to Nτ∼20 with ≲0.1% uncertainties. Making use of the scale setting parameters r0 and t0−−√ in the same range of β-values, these results lead to the independent continuum extrapolations Tcr0=0.7457(45) and Tct0−−√=0.2489(14), with the latter originating from a more convincing fit. Inserting a conversion of r0 from literature (unfortunately with much larger errors) yields Tc/ΛMS¯¯¯¯¯=1.24(10).

Longitudinal extension of myelomalacia by intramedullary and subdural hemorrhage in a canine model of spinal cord injury

BACKGROUND CONTEXT In canine intervertebral disc (IVD) extrusion, a spontaneous animal model of spinal cord injury, hemorrhage is a consistent finding. In rodent models, hemorrhage might be involved in secondary tissue destruction by biochemical mechanisms. PURPOSE This study aimed to investigate a causal association between the extents of intramedullary, subdural and epidural hemorrhage and the severity of spinal cord damage following IVD extrusion in dogs. STUDY DESIGN/SETTING A retrospective study using histologic spinal cord sections from 83 dogs euthanized following IVD extrusion was carried out. METHODS The degree of hemorrhage (intramedullary, subdural, epidural), the degree of spinal cord damage in the epicenter (white and gray matter), and the longitudinal extent of myelomalacia were graded. Associations between the extent of hemorrhage and the degree of spinal cord damage were evaluated statistically. RESULTS Intramedullary and subdural hemorrhages were significantly associated with the degree of white (p<.001/ p=.004) and gray (both p<.001) matter damage, and with the longitudinal extension of myelomalacia (p<.001/p=.005). Intriguingly, accumulation of hemorrhagic cord debris inside or dorsal to a distended and ruptured central canal in segments distant to the epicenter of the lesion was observed exhibiting a wave-like pattern on longitudinal assessment. The occurrence of this debris accumulation was associated with high degrees of tissue destruction (all p<.001). CONCLUSIONS Tissue liquefaction and increased intramedullary pressure associated with hemorrhage are involved in the progression of spinal cord destruction in a canine model of spinal cord injury and ascending or descending myelomalacia. Functional and dynamic studies are needed to investigate this concept further.

Unravelling the moisture sources of the Alpine Glaciers using tunnel valleys as constraints

A lack of archives has impeded reconstructions of moisture pathways for past glaciations in the European Alps. Here, we focus on the confluence area of two palaeoglaciers in the Swiss Plateau that were sourced on the northern (Aare glacier) and southern sides (Valais glacier) of the European Alps. We mapped tunnel valleys in the region using a drilling database, based on which we inferred the relative extent of each glacier c. 270 ka ago when the valleys were formed. We then compared this situation with that of the LGM. We found that, while the Valais glacier expanded farther into the foreland than the Aare glacier during the LGM, the opposite was the case c. 270 ka ago. We also found that LGM glaciers were non-erosive in the distal foreland. These contrasts in extents and erosional efficiencies imply differences in moisture pathways between the LGM and the time when the tunnel valleys were formed.

Propagation of Behavioral Variations with Delegation Proxies

Scoping behavioral variations to dynamic extents is useful to support non-functional concerns that otherwise result in cross-cutting code. Unfortunately, such forms of scoping are difficult to obtain with traditional reflection or aspects. We propose delegation proxies, a dynamic proxy model that supports behavioral intercession through the interception of various interpretation operations. Delegation proxies permit different behavioral variations to be easily composed together. We show how delegation proxies enable behavioral variations that can propagate to dynamic extents. We demonstrate our approach with examples of behavioral variations scoped to dynamic extents that help simplify code related to safety, reliability, and monitoring.

Virtual car accidents of epilepsy patients, interictal epileptic activity, and medication.

OBJECTIVE To investigate effects of interictal epileptic activity (IEA) and antiepileptic drugs (AEDs) on reactivity and aspects of the fitness to drive for epilepsy patients. METHODS Forty-six adult patients with demonstration of focal or generalized bursts of IEA in electroencephalography (EEG) readings within 1 year prior to inclusion irrespective of medication performed a car driving computer test or a single light flash test (39 patients performed both). Reaction times (RTs), virtual crashes, or lapses (RT ≥ 1 s in the car or flash test) were measured in an IEA burst-triggered fashion during IEA and compared with RT-measurements during unremarkable EEG findings in the same session. RESULTS IEA prolonged RTs both in the flash and car test (p < 0.001) in individual patients up to 200 ms. Generalized IEA with spike/waves (s/w) had the largest effect on RT prolongation (p < 0.001, both tests), whereas mean RT during normal EEG, age, gender, and number of AEDs had no effect. The car test was better than the flash test in detecting RT prolongations (p = 0.030). IEA increased crashes/lapses >26% in sessions with generalized IEA with s/w. The frequency of IEA-associated RT >1 s exceeded predictions (p < 0.001) based on simple RT shift, suggesting functional impairment beyond progressive RT prolongation by IEA. The number of AEDs correlated with prolonged RTs during normal EEG (p < 0.021) but not with IEA-associated RT prolongation or crashes/lapses. SIGNIFICANCE IEA prolonged RTs to varying extents, dependent on IEA type. IEA-associated RTs >1 s were more frequent than predicted, suggesting beginning cerebral decompensation of visual stimulus processing. AEDs somewhat reduced psychomotor speed, but it was mainly the IEA that contributed to an excess of virtual accidents.