The reduced form as an empirical tool: a cautionary tale from the financial veil

An analysis of the limitations of the reduced-form empirical strategy as a method of testing the Modigliani-Miller model of corporate financial structure, demonstrating that an empirical strategy that is not closely tied to an underlying economic theory of behavior will usually yield estimates that are too imprecise or too unreliable to form a basis for policy.Corporations - Finance ; Investments

Measuring Brief (Granger)

David Sive Award for Best Brief Overall

Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics

Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving biologically important tetrahydro-β-carbolines via a Friedel-Crafts mechanism

How long can fisheries management delay action in response to ecosystem and climate change?

Sustainable management of fisheries is often compromised by management delaying implementation of regulations that reduce harvest, in order to maintain higher catches in the short term. Decreases or increases in fish population growth rate driven by environmental change, including ecosystem and climate change, affect the harvest that can be taken sustainably. If not acted on rapidly, environmental change could result in unsustainable fishing or missed opportunity for higher catches. Using simulation models of harvested fish populations influenced by environmental change, we explore how long fisheries managers can afford to wait before changing harvest regulations in response to changes in population growth. If environmental change causes population declines, delays greater than five years increase the probability of population collapse. Species with fast and highly variable population growth rates are more susceptible to collapse under delays and should be a priority for revised management where delays occur. Generally, the long-term cost of delay, in terms of lost fishing opportunity, exceeds the short-term benefits of overfishing. Lowering harvest limits and monitoring for environmental change can alleviate the impact of delays; however, these measures may be more costly than reducing delays. We recommend that management systems that allow rapid responses to population growth changes be enacted for fisheries management to adapt to ecosystem and climate change

Perifollicular Hypopigmentation in Systemic Sclerosis: Associations With Clinical Features and Internal Organ Involvement

OBJECTIVE: To determine whether perifollicular hypopigmentation in systemic sclerosis (SSc) is associated with demographics, distinct clinical features, and autoantibody profiles. METHODS: Patients with SSc were prospectively enrolled, with a standardized data form used to collect anatomic distribution of perifollicular hypopigmentation. Associations between hypopigmentation and features of SSc were assessed. RESULTS: Of 179 adult patients with SSc, 36 (20%) patients had perifollicular hypopigmentation. Of these 36 patients, 94% (n = 34) were female and 33% (n = 12) had limited cutaneous SSc. In univariable logistic regression, Black race (odds ratio [OR] 15.63, 95% CI 6.6-37.20, CONCLUSION: Perifollicular hypopigmentation is observed in a subset of patients with SSc and associated with diffuse subtype. Larger prospective studies determining whether perifollicular hypopigmentation precedes end-organ involvement and whether specific patterns associate with internal organ involvement are needed

Regression of left ventricular hypertrophy after conversion to nocturnal hemodialysis

Regression of left ventricular hypertrophy after conversion to nocturnal hemodialysis.BackgroundLeft ventricular hypertrophy (LVH) is an independent risk factor for mortality in the dialysis population. LVH has been attributed to several factors, including hypertension, excess extracellular fluid (ECF) volume, anemia and uremia. Nocturnal hemodialysis is a novel renal replacement therapy that appears to improve blood pressure control.MethodsThis observational cohort study assessed the impact on LVH of conversion from conventional hemodialysis (CHD) to nocturnal hemodialysis (NHD). In 28 patients (mean age 44 ± 7 years) receiving NHD for at least two years (mean duration 3.4 ± 1.2 years), blood pressure (BP), hemoglobin (Hb), ECF volume (single-frequency bioelectrical impedance) and left ventricular mass index (LVMI) were determined before and after conversion. For comparison, 13 control patients (mean age 52 ± 15 years) who remained on self-care home CHD for one year or more (mean duration 2.8 ± 1.8 years) were studied also. Serial measurements of BP, Hb and LVMI were also obtained in this control group.ResultsThere were no significant differences between the two cohorts with respect to age, use of antihypertensive medications, Hb, BP or LVMI at baseline. After transfer from CHD to NHD, there were significant reductions in systolic, diastolic and pulse pressure (from 145 ± 20 to 122 ± 13mm Hg, P < 0.001; from 84 ± 15 to 74 ± 12mm Hg, P = 0.02; from 61 ± 12 to 49 ± 12mm Hg, P = 0.002, respectively) and LVMI (from 147 ± 42 to 114 ± 40 g/m2, P = 0.004). There was also a significant reduction in the number of prescribed antihypertensive medications (from 1.8 to 0.3, P < 0.001) and an increase in Hb in the NHD cohort. Post-dialysis ECF volume did not change. LVMI correlated with systolic blood pressure (r = 0.6, P = 0.001) during nocturnal hemodialysis. There was no relationship between changes in LVMI and changes in BP or Hb. In contrast, there were no changes in BP, Hb or LVMI in the CHD cohort over the same time period.ConclusionsReductions in BP with NHD are accompanied by regression of LVH