How cells control the overall size and growth of membrane-bound organelles is an important unanswered question of cell biology. Fission yeast cells maintain a nuclear size proportional to cellular ...size, resulting in a constant ratio between nuclear and cellular volumes (N/C ratio). We have conducted a genome-wide visual screen of a fission yeast gene deletion collection for viable mutants altered in their N/C ratio, and have found that defects in both nucleocytoplasmic mRNA transport and lipid synthesis alter the N/C ratio. Perturbing nuclear mRNA export results in accumulation of both mRNA and protein within the nucleus, and leads to an increase in the N/C ratio which is dependent on new membrane synthesis. Disruption of lipid synthesis dysregulates nuclear membrane growth and results in an enlarged N/C ratio. We propose that both properly regulated nucleocytoplasmic transport and nuclear membrane growth are central to the control of nuclear growth and size.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this introduction to the Policy Study Journal's special issue on punctuated equilibrium, we provide an overview of the approach, how it evolved, some of the major critiques directed at it, and ...some of the major developments it has spawned. We argue that the most important aspect of a theory or framework is not whether it is right or wrong, but the extent to which it is fruitful; that is, the extent to which it stimulated further research. Finally, we review the articles in this issue and put them in context.
In this article, we review two research programs that could benefit from a more extensive dialogue: media and policy studies of agenda setting. We focus on three key distinctions that divide these ...two robust research programs: the agenda(s) under investigation (public versus policymaking), the typical level of analysis (individual versus systemic), and framing effects (individual versus macro level). We map out these differences and their impacts on understanding the policy process. There is often a policy disconnect in the agenda-setting studies that emanate from the media tradition. Though interested in the effects of political communication, scholars from this tradition often fail to link the media to policy outcomes, policy change, or agenda change. Policy process scholars have increasingly rejected simple linear models in favor of models emphasizing complex feedback effects. This suggests a different role for the media-one of highlighting attributes in a multifaceted political reality and involvement in positive feedback cycles. Yet, political communication scholars have for the most part been insensitive to these potentials. We advocate a shared agenda centering on the role of the media in the political system from an information processing framework, emphasizing the reciprocal effects of each on the other.
Tree harvest and climate change can interact to have synergistic effects on tree species distribution changes. However, few studies have investigated the interactive effects of tree harvest and ...climate change on tree species distributions.
We assessed the interactive effects of tree harvest and climate change on the distribution of 29 dominant tree species at 270 m resolution in the southern United States, while accounting for species demography, competition, urban growth and natural fire. We simulated tree species distribution changes to year 2100 using a coupled forest dynamic model (LANDIS PRO), ecosystem process model (LINKAGES) and urban growth model (SLEUTH).
The distributions of 20 tree species contracted and nine species expanded within the region under climate change by end of 21st century. Distribution changes for all tree species were very slow and lagged behind the changes in potential distributions that were in equilibrium with new climatic conditions.
Tree harvest and climate change interacted to affect species occurrences and colonization but not extinction. Occurrence and colonization were mainly affected by tree harvest and its interaction with climate change while extinctions were mainly affected by tree harvest and climate change.
Synthesis and applications. Interactive effects of climate and tree harvest acted in the same direction as climate change effects on species occurrences, thereby accelerating climate change induced contraction or expansion of distributions. The overall interactive effects on species colonization were negative, specifically with positive interactive effects at leading edges of species ranges and negative interactive effects at trailing edges. Tree harvest generally did not interact with climate change to greatly facilitate or ameliorate species extinction. Our modelling results highlight the importance of considering disturbances and species demography (e.g. post‐harvest regeneration dynamics) when predicting changes in tree distributions.
Interactive effects of climate and tree harvest acted in the same direction as climate change effects on species occurrences, thereby accelerating climate‐change induced contraction or expansion of distributions. The overall interactive effects on species colonization were negative, specifically with positive interactive effects at leading edges of species ranges and negative interactive effects at trailing edges. Tree harvest generally did not interact with climate change to greatly facilitate or ameliorate species extinction. Our modelling results highlight the importance of considering disturbances and species demography (e.g. post‐harvest regeneration dynamics) when predicting changes in tree distributions.
Objective To evaluate trends in operative experience and to determine the effect of establishing the Surgical Council on Resident Education (SCORE) operative classification system on changes in ...operative volume among graduating surgery residents. Design The general surgery operative logs of graduating surgery residents from 2005 were retrospectively compared with residents who completed training in 2010 and 2011. Nonparametric statistical analyses were used (Mann-Whitney and median test) with significance set at p<0.01. Participants A total of 1022 residents completing residency in 2005 were compared with 1923 residents completing training in 2010-2011. Results Total operations reported increased from a median of 1023 to 1238 (21%) between 2005 and 2010-2011 (p<0.001). Cases increased in most SCORE categories. The median numbers of total, basic, and complex laparoscopic operations increased by 49%, 37%, and 82%, respectively, over the 5-year interval (p<0.001). Open cavitary (thoracic + abdominal) operations decreased by 5%, whereas other major operations increased by 35% (both p<0.001). The frequency of discrete operations done at least 10 times during residency did not change. The median number of SCORE essential-common operations performed ranged from 1 to 107, whereas essential-uncommon operations ranged from 0 to 4. Twenty-three of 67 SCORE essential-common operations (34%) had a median of less than 5 and 4 had a median of 0. Conclusions The operative volume of graduating surgical residents has increased by 21% since 2005; however, the number of operations done 10 times or greater has not changed. Although open cavitary procedures continue to decline, there has been a large increase in endoscopy, complex laparoscopic, and other major operations. Some essential-common operations continue to be performed infrequently. These results suggest that education in the operating room must improve and alternate methods for teaching infrequently performed procedures are needed.
Benzoyl peroxide (BPO) solutions effectively reduce Cutibacterium acnes (formerly Propionibacterium acnes) on the face, neck, and back in nonoperative settings. This study compared preoperative ...application of BPO vs. chlorhexidine gluconate (CHG) in decreasing shoulder C acnes skin burden in surgical patients.
Eighty patients undergoing shoulder surgery were prospectively enrolled in a randomized double-blind trial at 1 institution from August 2015 to April 2017. Participants were randomized to 5% BPO or 4% CHG for 3 consecutive days. The nonoperative shoulder had no intervention and served as the negative control. Skin cultures of both shoulders were obtained via a detergent scrub technique the day of surgery at anterior, lateral, and posterior sites and the axilla.
Fewer positive cultures were obtained from the BPO-treated side compared with the contralateral side (P = .0003), and no change was shown for the CHG group (P = .80). Shoulders treated with BPO showed a statistically significant reduction in C acnes counts compared with CHG at anterior (P = .03) and posterior (P = .005) portal sites. No significant difference was found at the axilla (P = .99) or lateral portal site (P = .08). No postoperative infections or wound complications occurred in either group.
BPO is more effective than CHG at reducing C acnes on the shoulder. Decreasing the skin burden of C acnes may reduce intraoperative wound contamination and postoperative infection. BPO should be considered as an adjunctive preoperative skin preparation considering its potential benefit, low risk, and low cost.
In the Southern Hemisphere 2010 influenza season, Seqirus’ split-virion, trivalent inactivated influenza vaccine was associated with increased reports of fevers and febrile reactions in young ...children. A staged clinical development program of a quadrivalent vaccine (Seqirus IIV4 S-IIV4; Afluria® Quadrivalent/Afluria Quad™/Afluria Tetra™), wherein each vaccine strain is split using a higher detergent concentration to reduce lipid content (considered the cause of the increased fevers and febrile reactions), is now complete.
Children aged 6–59 months were randomized 3:1 and stratified by age (6–35 months/36–59 months) to receive S-IIV4 (n = 1684) or a United States (US)-licensed comparator IIV4 (C-IIV4; Fluzone® Quadrivalent; n = 563) during the Northern Hemisphere 2016–2017 influenza season. The primary objective was to demonstrate noninferior immunogenicity of S-IIV4 versus C-IIV4. Immunogenicity was assessed by hemagglutination inhibition (baseline, 28 days postvaccination). Solicited, unsolicited, and serious adverse events were assessed for 7, 28, and 180 days postvaccination, respectively.
S-IIV4 met the immunogenicity criteria for noninferiority. Adjusted geometric mean titer ratios (C-IIV4/S-IIV4) for the A/H1N1, A/H3N2, B/Yamagata, and B/Victoria strains were 0.79 (95% CI: 0.72, 0.88), 1.27 (1.15, 1.42), 1.12 (1.01, 1.24), and 0.97 (0.86, 1.09), respectively. Corresponding values for differences in seroconversion rates (C-IIV4 minus S-IIV4) were −10.3 (−15.4, −5.1), 2.6 (−2.5, 7.8), 3.1 (−2.1, 8.2), and 0.9 (−4.2, 6.1). Solicited, unsolicited, and serious adverse events were similar between vaccines in both age cohorts, apart from fever. Fever rates were lower with S-IIV4 (5.8%) than C-IIV4 (8.4%), with no febrile convulsions reported with either vaccine during the 7 days postvaccination.
S-IIV4, manufactured with a higher detergent concentration, demonstrated noninferior immunogenicity to the US-licensed C-IIV4, with similar postvaccination safety and tolerability, in children aged 6–59 months. This completes the program demonstrating the immunogenicity and safety of S-IIV4 in participants aged 6 months and older.
Seqirus Pty Ltd; ClinicalTrials.gov identifier:NCT02914275.
Punctuated Equilibrium in Comparative Perspective Baumgartner, Frank R.; Breunig, Christian; Green-Pedersen, Christoffer ...
American journal of political science,
07/2009, Letnik:
53, Številka:
3
Journal Article
Recenzirano
We explore the impact of institutional design on the distribution of changes in outputs of governmental processes in the United States, Belgium, and Denmark. Using comprehensive indicators of ...governmental actions over several decades, we show that in each country the level of institutional friction increases as we look at processes further along the policy cycle. Assessing multiple policymaking institutions in each country allows us to control for the nature of the policy inputs, as all the institutions we consider cover the full range of social and political issues in the country. We find that all distributions exhibit high kurtosis values, significantly higher than the Normal distribution which would be expected if changes in government attention and activities were proportionate to changes in social inputs. Further, in each country, those institutions that impose higher decision-making costs show progressively higher kurtosis values. The results suggest general patterns that we hypothesize to be related to boundedly rational behavior in a complex social environment.
IMPORTANCE: In 2011, the Accreditation Council for Graduate Medical Education (ACGME) restricted resident duty hour requirements beyond those established in 2003, leading to concerns about the ...effects on patient care and resident training. OBJECTIVE: To determine if the 2011 ACGME duty hour reform was associated with a change in general surgery patient outcomes or in resident examination performance. DESIGN, SETTING, AND PARTICIPANTS: Quasi-experimental study of general surgery patient outcomes 2 years before (academic years 2009-2010) and after (academic years 2012-2013) the 2011 duty hour reform. Teaching and nonteaching hospitals were compared using a difference-in-differences approach adjusted for procedural mix, patient comorbidities, and time trends. Teaching hospitals were defined based on the proportion of cases at which residents were present intraoperatively. Patients were those undergoing surgery at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). General surgery resident performance on the annual in-training, written board, and oral board examinations was assessed for this same period. EXPOSURES: National implementation of revised resident duty hour requirements on July 1, 2011, in all ACGME accredited residency programs. MAIN OUTCOMES AND MEASURES: Primary outcome was a composite of death or serious morbidity; secondary outcomes were other postoperative complications and resident examination performance. RESULTS: In the main analysis, 204 641 patients were identified from 23 teaching (n = 102 525) and 31 nonteaching (n = 102 116) hospitals. The unadjusted rate of death or serious morbidity improved during the study period in both teaching (11.6% 95% CI, 11.3%-12.0% to 9.4% 95% CI, 9.1%-9.8%, P < .001) and nonteaching hospitals (8.7% 95% CI, 8.3%-9.0% to 7.1% 95% CI, 6.8%-7.5%, P < .001). In adjusted analyses, the 2011 ACGME duty hour reform was not associated with a significant change in death or serious morbidity in either postreform year 1 (OR, 1.12; 95% CI, 0.98-1.28) or postreform year 2 (OR, 1.00; 95% CI, 0.86-1.17) or when both postreform years were combined (OR, 1.06; 95% CI, 0.93-1.20). There was no association between duty hour reform and any other postoperative adverse outcome. Mean (SD) in-training examination scores did not significantly change from 2010 to 2013 for first-year residents (499.7 85.2 to 500.5 84.2, P = .99), for residents from other postgraduate years, or for first-time examinees taking the written or oral board examinations during this period. CONCLUSIONS AND RELEVANCE: Implementation of the 2011 ACGME duty hour reform was not associated with a change in general surgery patient outcomes or differences in resident examination performance. The implications of these findings should be considered when evaluating the merit of the 2011 ACGME duty hour reform and revising related policies in the future.
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