Ontogenetic diet shifts in Nassau grouper: Trophic linkages and predatory impact

Understanding which fauna and flora from seagrass beds serve as primary food for reef-based commuters is critical in defining trophic linkages between shallow-water habitats of tropical oceanic regions. Although numerous studies have documented the relative importance of crustaceans in the diet of reef fishes associated with tropical seagrass meadows, it is unknown if trophic importance corresponds to a significant effect on prey distribution and abundance patterns. We quantified size-specific diet of juvenile Nassau grouper (Epinephelus striatus) inhabiting natural and artificial patch reefs, and manipulated the density of artificial patch reefs (0, 8, and 16 patch reefs per ha) to examine the predatory impact of patch reef associates on nocturnally foraging crabs. Stomach content analysis indicated an ontogenetic shift in diet, where small grouper (TL) consumed mainly brachyuran crabs and other small crustaceans, and large grouper (\u3e30 cm TL) consumed primarily fish. Mid-size fish (20.0-29.9 cm TL) were transitional in diet, with crustaceans occurring more frequently than fish. Diet was least diverse for large fish, and nearly identical for mid-size and small fish. Similar numbers of prey taxa were ingested in natural and artificial patch reefs. Before patch reefs were deployed in the field, nighttime band censuses revealed a mean density of 3 crabs per 240 m(2) (ranges = 0-8 crabs/transect) in nearby seagrass beds. After patch reefs were deployed, crab densities dropped by one-half to 43-fold in sites with patch reefs compared to control sites (0 patch reefs). There was a negative and significant relationship between grouper density (no. ha(-1)) and crab density (no. 240 m(-2)) at all sites and locations combined. These results suggest that patch reef associated predators have a significant predatory impact on nocturnally foraging crabs in adjacent seagrass meadows, and highlight an important trophic link between tropical patch reef and seagrass habitats

Predator and shelter-size effects on coral reef fish and spiny lobster prey

Population dynamics of coral reef fishes and spiny lobster appear to be determined by variable recruitment interacting with post-settlement processes, particularly predation. The risk of predation may be modified by the scaling between prey and shelter size, which enhances the protective capacity of a reef. We experimentally tested these predictions by manipulating densities of predatory Nassau grouper Epinephelus striatus on 8 artificial patch reefs of 2 sizes (small, large) in a large seagrass bed near Lee Stocking Island, Bahamas. We initially censused patch reefs for 7 mo, after which we randomly selected equivalent numbers of small and large reefs to serve as permanent grouper removal versus control (non-removal) reefs. We continued to census patch reefs for 12 mo after predators were removed from certain reefs. The abundance of predatory Nassau grouper and the size of shelters from predation jointly explained the observed distribution and abundance patterns of spiny lobster and reef fish prey inhabiting artificial patch reef habitats. For example, the abundance of small lobsters was highest in small reefs where Nassau grouper were experimentally removed. When we assessed the effects of predator abundance on all reef fish prey (1 to 10 cm TL), we were unable to detect any significant effects on prey abundance or species diversity due to low statistical power. However, the total abundance and species richness of medium size reef fish (4 to 10 cm TL) was significantly higher in small shelters from which grouper were removed. In comparing species\u27 relative abundances on reefs with low versus high numbers and Nassau grouper, the results indicated that grouper reduce prey abundances in a generalized, non-selective pattern, with no difference in the number of rare versus common prey species that were extirpated. Thus, juvenile Nassau grouper inhabiting certain patch reefs produce a general predatory impact, whereby predation reduces prey abundance and diversity in proportion to the initial relative abundance of prey. Our results support the prediction that at certain scales of space and time, post-settlement predation is a critical determinant of population abundance and species diversity of reef-fish and spiny lobster prey, and that the effect of predation is mediated by the protective capacity of a reef

Quantum enhanced positioning and clock synchronization

A wide variety of positioning and ranging procedures are based on repeatedly sending electromagnetic pulses through space and measuring their time of arrival. This paper shows that quantum entanglement and squeezing can be employed to overcome the classical power/bandwidth limits on these procedures, enhancing their accuracy. Frequency entangled pulses could be used to construct quantum positioning systems (QPS), to perform clock synchronization, or to do ranging (quantum radar): all of these techniques exhibit a similar enhancement compared with analogous protocols that use classical light. Quantum entanglement and squeezing have been exploited in the context of interferometry, frequency measurements, lithography, and algorithms. Here, the problem of positioning a party (say Alice) with respect to a fixed array of reference points will be analyzed.Comment: 4 pages, 2 figures. Accepted for publication by Natur

Differential Dynamics of Transposable Elements during Long-Term Diploidization of Nicotiana Section Repandae (Solanaceae) Allopolyploid Genomes

PubMed ID: 23185607This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Biophysics - Quantum path to photosynthesis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62904/1/446740a.pd

Altering crystal growth and annealing in ice-templated scaffolds.

The potential applications of ice-templating porous materials are constantly expanding, especially as scaffolds for tissue engineering. Ice-templating, a process utilizing ice nucleation and growth within an aqueous solution, consists of a cooling stage (before ice nucleation) and a freezing stage (during ice formation). While heat release during cooling can change scaffold isotropy, the freezing stage, where ice crystals grow and anneal, determines the final size of scaffold features. To investigate the path of heat flow within collagen slurries during solidification, a series of ice-templating molds were designed with varying the contact area with the heat sink, in the form of the freeze drier shelf. Contact with the heat sink was found to be critical in determining the efficiency of the release of latent heat within the perspex molds. Isotropic collagen scaffolds were produced with pores which ranged from 90 μm up to 180 μm as the contact area decreased. In addition, low-temperature ice annealing was observed within the structures. After 20 h at -30 °C, conditions which mimic storage prior to lyophilization, scaffold architecture was observed to coarsen significantly. In future, ice-templating molds should consider not only heat conduction during the cooling phase of solidification, but the effects of heat flow during ice growth and annealing.The authors gratefully acknowledge the financial support of the Gates Cambridge Trust, the Newton Trust, and ERC Advanced Grant 320598 3D-E. A.H. held a Daphne Jackson Fellowship funded by the University of Cambridge.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10853-015-9343-

Cost of diabetes care in out-patient clinics of Karachi, Pakistan

<p>Abstract</p> <p>Background</p> <p>Diabetes Mellitus (DM) is a growing epidemic and the cost of treating diabetes is largely increasing. The objective of this study was to estimate the cost-of-illness of DM among attendees of out-patient clinics in Karachi, Pakistan. This is the first study conducted from a societal perspective to estimate the cost of managing diabetes in Pakistan.</p> <p>Methods</p> <p>A prevalence-based 'Cost-of-Illness' study for diabetes care was conducted in six different out-patient clinics of Karachi, Pakistan from July to September 2006. A pre-tested questionnaire was administered to collect the data from 345 randomly selected persons with diabetes.</p> <p>Results</p> <p>The annual mean direct cost for each person with diabetes was estimated to be Pakistani rupees 11,580 (US$ 197). Medicines accounted for the largest share of direct cost (46%), followed by laboratory investigations (32%). We found that increased age, the number of complications and longer duration of the disease significantly increase the burden of cost on society (p < 0.001). Comparing cost with family income it was found that the poorest segment of society is spending 18% of total family income on diabetes care.</p> <p>Conclusion</p> <p>This study concluded that substantial expenditure is incurred by people with diabetes; with the implication that resources could be saved by prevention, earlier detection and a reduction in diabetes co-morbidities and complications through improved diabetes care. Large scale and cost-effective prevention programs need to be initiated to maximise health gains and to reverse the advance of this epidemic.</p

Dose dependent effect of statins on postoperative atrial fibrillation after cardiac surgery among patients treated with beta blockers

<p>Abstract</p> <p>Background</p> <p>Previous studies on the effects of Statins in preventing atrial fibrillation (AF) after cardiac surgery have shown conflicting results. Whether statins prevent AF in patients treated with postoperative beta blockers and whether the statin-effect is dose related are unknown.</p> <p>Methods</p> <p>We retrospectively studied 1936 consecutive patients who underwent coronary artery bypass graft (CABG) (n = 1493) or valve surgery (n = 443) at the Minneapolis Veterans Affairs Medical Center. All patients were in sinus rhythm before the surgery. Postoperative beta blockers were administered routinely (92% within 24 hours postoperatively).</p> <p>Results</p> <p>Mean age was 66+10 years and 68% of the patients were taking Statins. Postoperative AF occurred in 588 (30%) patients and led to longer length of stay in the intensive care unit versus those without AF (5.1+7.6 days versus 2.5+2.3 days, p < 0.0001). Patients with a past history of AF had a 5 times higher risk of postoperative AF (odds ratio 5.1; 95% confidence interval 3.4 to 7.7; p < 0.0001). AF occurred in 31% of patients taking statins versus 29% of the others (p = 0.49). In multivariable analysis, statins were not associated with AF (odds ratio (OR) 0.93, 95% confidence interval (CI) 0.7 to 1.2; p = 0.59). However, in a subgroup analysis, the patients treated with Simvastatin >20 mg daily had a 36% reduction in the risk of postoperative AF (OR 0.64, 95% CI 0.43 to 0.6; p = 0.03) in comparison to those taking lower dosages.</p> <p>Conclusion</p> <p>Among cardiac surgery patients treated with postoperative beta blockers Statin treatment reduces the incidence of postoperative AF when used at higher dosages</p

Partial pulmonary embolization disrupts alveolarization in fetal sheep

BACKGROUND: Although bronchopulmonary dysplasia is closely associated with an arrest of alveolar development and pulmonary capillary dysplasia, it is unknown whether these two features are causally related. To investigate the relationship between pulmonary capillaries and alveolar formation, we partially embolized the pulmonary capillary bed. METHODS: Partial pulmonary embolization (PPE) was induced in chronically catheterized fetal sheep by injection of microspheres into the left pulmonary artery for 1 day (1d PPE; 115d gestational age; GA) or 5 days (5d PPE; 110-115d GA). Control fetuses received vehicle injections. Lung morphology, secondary septal crests, elastin, collagen, myofibroblast, PECAM1 and HIF1 alpha abundance and localization were determined histologically. VEGF-A, Flk-1, PDGF-A and PDGF-R alpha mRNA levels were measured using real-time PCR. RESULTS: At 130d GA (term approximately 147d), in embolized regions of the lung the percentage of lung occupied by tissue was increased from 29 +/- 1% in controls to 35 +/- 1% in 1d PPE and 44 +/- 1% in 5d PPE fetuses (p < 0.001). Secondary septal crest density was reduced from 8 +/- 0% in controls to 5 +/- 0% in 1d PPE and 4 +/- 0% in 5d PPE fetuses (p < 0.05), indicating impaired alveolar formation. The deposition of differentiated myofibroblasts (23 +/- 1% vs 28 +/- 1%; p < 0.001) and elastin fibres (3 +/- 0% vs 4 +/- 0%; p < 0.05) were also impaired in embolized lung regions of PPE fetuses compared to controls. PPE did not alter the deposition of collagen or PECAM1. At 116d GA in 5d PPE fetuses, markers of hypoxia indicated that a small and transient hypoxic event had occurred (hypoxia in 6.7 +/- 1.4% of the tissue within embolized regions of 5d PPE fetuses at 116d compared to 0.8 +/- 0.2% of tissue in control regions). There was no change in the proportion of tissue labelled with HIF1 alpha. There was no change in mRNA levels of the angiogenic factors VEGF and Flk-1, although a small increase in PDGF-R alpha expression at 116d GA, from 1.00 +/- 0.12 in control fetuses to 1.61 +/- 0.18 in 5d PPE fetuses may account for impaired differentiation of alveolar myofibroblasts and alveolar development. CONCLUSIONS: PPE impairs alveolarization without adverse systemic effects and is a novel model for investigating the role of pulmonary capillaries and alveolar myofibroblasts in alveolar formation

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)