We investigated the relative densities of granivorous, nocturnal desert rodents in small plots within two arid regions of Arizona to study how sympatric species avoid competitive extinction. The most common rodents were kangaroo rats, Dipodomys spp., and pocket mice, Perognathus spp. We attempted correlating the density of each species with several environmental measurements, derived from the soil's i) depth; ii) texture or iii) resistance to sheer stress; or from the plant's i) species diversity; ii) growth forms or iii) foliage density. Successful variables were derived from plant growth form and foliage density. The soil's resistance to sheer stress also seemed important for a few species. In general, kangaroo rats were associated with sparseness of vegetation; pocket mice with denseness. One group of mice, which we term bush mice, seemed to require bushes and included two Perognathus spp., three Peromyscus spp., and probably a harvest mouse (Reithrodontomys fulvescens). Two other Perognathus spp. were taken in grassy habitats. Some suitable habitats tended to be complementary to others, suggesting that species associated with them are competitors. Comparisons of the density and distribution of D. merriami, present in both regions but under different biotic circumstances, reinforces the opinion that competition is responsible for the complementariness of habitats. In some cases the evidence suggests that competitive coexistence is accounted for by the fact that different specializations are needed to escape predation in different environments. We use variables which correlate with the relative density of various species to construct a model of habitat complexity. The rodent species diversities obtained in our plots can be approximately accounted for by this model. The model is based on the premises that the rodents collectively discriminate four qualities of soil surface, and three heights and two densities of vegetation. In general, specializations based on biotic variables appear most important.

Reports of widespread thromboses and disseminated intravascular coagulation (DIC) in patients with coronavirus disease 19 (COVID-19) have been rapidly increasing in number. Key features of this disorder include a lack of bleeding risk, only mildly low platelet counts, elevated plasma fibrinogen levels, and detection of both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and complement components in regions of thrombotic microangiopathy (TMA). This disorder is not typical DIC. Rather, it might be more similar to complement-mediated TMA syndromes, which are well known to rheumatologists who care for patients with severe systemic lupus erythematosus or catastrophic antiphospholipid syndrome. This perspective has critical implications for treatment. Anticoagulation and antiviral agents are standard treatments for DIC but are gravely insufficient for any of the TMA disorders that involve disorders of complement. Mediators of TMA syndromes overlap with those released in cytokine storm, suggesting close connections between ineffective immune responses to SARS-CoV-2, severe pneumonia and life-threatening microangiopathy.

A geriatrician stands by during his father's downward spiral into old age, disability, and dementia.b y J e r a l d W i n a k u r M y fat h e r i s e i g h t y-s i x years old. He was never a big man, except perhaps to me when I was his little boy. At most he was five feet, eight inches tall and weighed 160 pounds. Today he weighs barely 120. Maybe he is five feet two. He teeters on spindly legs, a parched blade of grass in the wind, refusing the walker his doctor recommends or the arm extended in support by those of us who love him. He doesn't know what day it is. He sleeps most of the time, barely eats. Shaving exhausts him. His clothes hang like a scarecrow's. Getting him in for a haircut is a major ordeal. He is very deaf but won't wear his hearing aids or loses them as often as a kid might misplace his marbles. He drives my mother-five years younger-crazy to tears.My only sibling, the architect, asks me every time we are together (which is often because we all live in the same town) and every time we speak on the phone (which is almost every day because we are a close family now in crisis): "What are we going to do with Dad?" As if there must be a definitive answer, some fix-say, putting a grab bar in the bathroom or increasing the width of the doorways. Something that is according to code.He asks me this question not just out of fear and frustration, not only out of a realization that it is time for the adult children of a progressively dementing elderly 1 0 6 4 J u l y /A u g u s t 2 0 0 5 N a r r a t i v e M a t t e r s

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