The rate of force generation by the myocardium is not influenced by afterload

The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt) and isolated papillary muscle of rats (dT/dt). Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/kg oxprenolol plus 0.5 mg/kg atropine). A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP). A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H1 and H2) above control values (condition C). After arterial pressure elevations (systolic pressure C: 119 ± 8.1; H1: 142 ± 7.9; H2 166 ± 7.7 mmHg; P<0.01), there were no significant differences in heart rate (C: 125 ± 13.9; H1: 125 ± 13.5; H2: 123 ± 14.1 bpm; P>0.05) or LVEDP (C: 6.2 ± 2.48; H1: 6.3 ± 2.43; H2: 6.1 ± 2.51 mmHg; P>0.05). The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 ± 1,057; H1: 3,112 ± 996; H2: 3,086 ± 980 mmHg/s; P>0.05). In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 ± 13; 75%: 80 ± 13; 50%: 79 ± 11 g mm-2 s-1, P>0.05). The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt

Clinical evaluation of the failure rate of metallic brackets bonded with orthodontic composites

The purpose of the present study was to evaluate in vivo the failure rate of metallic brackets bonded with two orthodontic composites. Nineteen patients with ages ranging from 10.5 to 38.7 years needing corrective orthodontic treatment were selected for study. The enamel surfaces from second premolars to second premolars were treated with Transbond Plus-Self Etching Primer (3M Unitek). Next, 380 orthodontic brackets were bonded on maxillary and mandibular teeth, as follows: 190 with Transbond XT composite (3M Unitek) (control) and 190 with Transbond Plus Color Change (3M Unitek) (experimental) in contralateral quadrants. The bonded brackets were light cured for 40 s, and initial alignment archwires were inserted. Bond failure rates were recorded over a six-month period. At the end of the evaluation, six bond failures occurred, three for each composite. Kaplan-Meyer method and log-rank test (Mantel-Cox) was used for statistical analysis, and no statistically significant difference was found between the materials (p=0.999). Both Transbond XT and Transbond Plus Color Change composites had low debonding rates over the study period.

Are early and late rate of force development differently influenced by fast-velocity resistance training?

This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s-1) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, ..., 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N{bullet operator}m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N{bullet operator}m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC{bullet operator}s-1) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force. © 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Age and gender influence the cardiorespiratory function and metabolic rate of broiler chicks during normocapnia and hypercapnia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Physiological responses and rate of perceived exertion in Brazilian jiu-jitsu athletes

In this study, the physiological responses and rate of perceived exertion in Brazilian jiu-jitsu fighters submitted to a combat simulation were investigated. Venous blood samples and heart rate were taken from twelve male Brazilian jiu-jitsu athletes (27.1+/-2.7 yrs, 75.4+/-8.8 kg, 174.9+/-4.4 cm, 9.2+/-2.4% fat), at rest, after a warm-up (ten minutes), immediately after the fight simulation (seven minutes) and after recovery (fourteen minutes). After the combat the rate of perceived exertion was collected. The combat of the Brazilian jiu-jitsu fighters did not change blood concentrations of glucose, triglycerides, total cholesterol, low density lipoprotein and very low density lipoprotein, ureia and ammonia. However, blood levels of high density lipoprotein were significantly higher post-fight (before: 43.0+/-6.9 mg/dL, after: 45.1+/-8.0 mg/dL) and stayed at high levels during the recovery period (43.6+/-8.1 mg/dL) compared to the rest values (40.0+/-6.6 mg/dL). The fight did not cause changes in the concentrations of the cell damage markers of creatine kinase, aspartate aminotransferase and creatinine. However, blood concentrations of the alanine aminotransferase (before: 16.1+/-7.1 U/L, after: 18.6+/-7.1 U/L) and lactate dehydrogenase (before: 491.5+/-177.6 U/L, after: 542.6+/-141.4 U/L) enzymes were elevated after the fight. Heart rate (before: 122+/-25 bpm, after: 165+/-17 bpm) and lactate (before: 2.5+/-1.2 mmol/L, after: 11.9+/-5.8 mmol/L) increased significantly with the completion of combat. Despite this, the athletes rated the fight as being light or somewhat hard (12+/-2). These results showed that muscle glycogen is not the only substrate used in Brazilian jiu-jitsu fights, since there are indications of activation of the glycolytic, lipolytic and proteolytic pathways. Furthermore, the athletes rated the combats as being light or somewhat hard although muscle damage markers were generated.

Rates of Change in the Visual Field and Optic Disc in Patients with Distinct Patterns of Glaucomatous Optic Disc Damage

Purpose: To investigate the rate of visual field and optic disc change in patients with distinct patterns of glaucomatous optic disc damage. Design: Prospective longitudinal study. Participants: A total of 131 patients with open-angle glaucoma with focal (n = 45), diffuse (n = 42), and sclerotic (n = 44) optic disc damage. Methods: Patients were examined every 4 months with standard automated perimetry (SAP, SITA Standard, 24-2 test, Humphrey Field Analyzer, Carl Zeiss Meditec, Dublin, CA) and confocal scanning laser tomography (CSLT, Heidelberg Retina Tomograph, Heidelberg Engineering GmbH, Heidelberg, Germany) for a period of 4 years. During this time, patients were treated according to a predefined protocol to achieve a target intraocular pressure (IOP). Rates of change were estimated by robust linear regression of visual field mean deviation (MD) and global optic disc neuroretinal rim area with follow-up time. Main Outcome Measures: Rates of change in MD and rim area. Results: Rates of visual field change in patients with focal optic disc damage (mean -0.34, standard deviation [SD] 0.69 dB/year) were faster than in patients with sclerotic (mean - 0.14, SD 0.77 dB/year) and diffuse (mean + 0.01, SD 0.37 dB/year) optic disc damage (P = 0.003, Kruskal-Wallis). Rates of optic disc change in patients with focal optic disc damage (mean - 11.70, SD 25.5 x 10(-3) mm(2)/year) were faster than in patients with diffuse (mean -9.16, SD 14.9 x 10(-3) mm(2)/year) and sclerotic (mean -0.45, SD 20.6 x 10(-3) mm(2)/year) optic disc damage, although the differences were not statistically significant (P = 0.11). Absolute IOP reduction from untreated levels was similar among the groups (P = 0.59). Conclusions: Patients with focal optic disc damage had faster rates of visual field change and a tendency toward faster rates of optic disc deterioration when compared with patients with diffuse and sclerotic optic disc damage, despite similar IOP reductions during follow-up. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2012; 119: 294-303 (C) 2012 by the American Academy of Ophthalmology.

Clinical evaluation of the failure rate of metallic brackets bonded with orthodontic composites

The purpose of the present study was to evaluate in vivo the failure rate of metallic brackets bonded with two orthodontic composites. Nineteen patients with ages ranging from 10.5 to 38.7 years needing corrective orthodontic treatment were selected for study. The enamel surfaces from second premolars to second premolars were treated with Transbond Plus-Self Etching Primer (3M Unitek). Next, 380 orthodontic brackets were bonded on maxillary and mandibular teeth, as follows: 190 with Transbond XT composite (3M Unitek) (control) and 190 with Transbond Plus Color Change (3M Unitek) (experimental) in contralateral quadrants. The bonded brackets were light cured for 40 s, and initial alignment archwires were inserted. Bond failure rates were recorded over a six-month period. At the end of the evaluation, six bond failures occurred, three for each composite. Kaplan-Meyer method and log-rank test (Mantel-Cox) was used for statistical analysis, and no statistically significant difference was found between the materials (p=0.999). Both Transbond XT and Transbond Plus Color Change composites had low debonding rates over the study period.

Razor Thin Win: The 1972 Constitution Ballot, Campaign, Ratification & the Courts -- Mae Nan (Robinson) Ellingson & Mick McKeon “In the Crucible of Change”

Beyond the challenge of crafting a new state Constitution that empowered the people and modernized and opened up state and local government in Montana, the Constitutional Convention delegates, as they signed the final document, looked forward to the arduous task of getting it ratified by the electorate in a short ten week period between the end of the convention on March 24 and the ratification election of June 6, 1972. While all 100 delegates signed the draft Constitution, not all supported its adoption. But the planning about how to get it adopted went back to the actions of the Convention itself, which carefully crafted a ballot that kept “hot political issues” from potentially killing the entire document at the polls. As a result, three side issues were presented to the electorate on the ballot. People could vote for or against those side issues and still vote to ratify the entire document. Thus, the questions of legalizing gambling, having a unicameral legislature and retaining the death penalty were placed separately on the ballot (gambling passed, as did the retention of the death penalty, but the concept of a one-house legislature was defeated). Once the ballot structure was set, delegates who supported the new Constitution organized a grassroots, locally focused effort to secure ratification – thought hampered by a MT Supreme Court decision on April 28 that they could not expend $45,000 in public monies that they had set aside for voter education. They cobbled together about $10,000 of private money and did battle with the established political forces, led by the MT Farm Bureau, MT Stockgrowers’ Assn. and MT Contractors Assn., on the question of passage. Narrow passage of the main document led to an issue over certification and a Montana Supreme Court case challenging the ratification vote. After a 3-2 State Supreme Court victory, supporters of the Constitution then had to defend the election results again before the federal courts, also a successful effort. Montana finally had a new progressive State Constitution that empowered the people, but the path to it was not clear and simple and the win was razor thin. The story of that razor thin win is discussed in this chapter by the two youngest delegates to the 1972 Constitutional Convention, Mae Nan Ellingson of Missoula and Mick McKeon, then of Anaconda. Both recognized “Super Lawyers in their later professional practices were also significant players in the Constitutional Convention itself and actively participated in its campaign for ratification. As such, their recollections of the effort provide an insider’s perspective of the struggle to change Montana for the better through the creation and adoption of a new progressive state Constitution “In the Crucible of Change.” Mae Nan (Robinson) Ellingson was born Mae Nan Windham in Mineral Wells, TX and graduated from Mineral Wells High School in 1965 and Weatherford College in Weatherford, TX in 1967. Mae Nan was the youngest delegate at the 1972 Convention from Missoula. She moved to Missoula in 1967 and received her BA in Political Science with Honors from the University of MT in 1970. She was a young widow known by her late husband’s surname of Robinson while attending UM graduate school under the tutelage of noted Professor Ellis Waldron when he persuaded her to run for the Constitutional Convention. Coming in a surprising second in the delegate competition in Missoula County she was named one of the Convention’s “Ten Outstanding Constitutional Convention Delegates,” an impressive feat at such a young age. She was 24 at the time, the youngest person to serve at the ConCon, and one of 19 women out of 100 delegates. In the decade before the Convention, there were never more than three women Legislators in any session, usually one or two. She was a member of the American Association of University Women, a Pi Sigma Alpha political science honorary, and a Phi Alpha Theta historical honorary. At the Convention, she led proposals for the state's bill of rights, particularly related to equal rights for women. For years, Ellingson kept a copy of the preamble to the Constitution hanging in her office; while all the delegates had a chance to vote on the wording, she and delegate Bob Campbell are credited with the language in the preamble. During the convention, she had an opportunity that opened the door to her later career as an attorney. A convention delegate suggested to her that she should go to law school. Several offered to help, but at the time she couldn't go to school. Her mom had died in Texas, and she ended up with a younger brother and sister to raise in Missoula. She got a job teaching, but about a year later, intrigued with the idea of pursuing the law as a career, she called the man back to ask about the offer. Eventually another delegate, Dave Drum of Billings, sponsored her tuition at the UM School of Law. After receiving her JD with Honors (including the Law Review and Moot Court) from the UM Law School Ellingson worked for the Missoula city attorney's office for six years (1977-83), and she took on landmark projects. During her tenure, Missoula became the first city to issue open space bonds, a project that introduced her to Dorsey & Whitney. The city secured its first easement on Mount Sentinel, and it created the trail along the riverfront with a mix of playing fields and natural vegetation. She also helped develop a sign ordinance for the city of Missoula. She ended up working as bond counsel for Dorsey & Whitney, and she opened up the firm's full-fledged Missoula office after commuting a couple of years to its Great Falls office. She was a partner at Dorsey Whitney, working there from 1983 until her retirement in 2012. The area of law she practiced there is a narrow specialty - it requires knowledge of constitutional law, state and local government law, and a slice of federal tax law - but for Ellingson it meant working on great public projects – schools, sewer systems, libraries, swimming pools, ire trucks. At the state level, she helped form the Montana Municipal Insurance Authority, a pooled insurance group for cities. She's shaped MT’s tax increment law, and she was a fixture in the MT Legislature when they were debating equal rights. As a bond lawyer, though, Ellingson considers her most important work for the state to be setting up the Intercap Program that allowed local governments to borrow money from the state at a low interest rate. She has been a frequent speaker at the League of Cities and Towns, the Montana Association of Counties, and the Rural Water Users Association workshops on topics related to municipal finance, as well as workshops sponsored by the DNRC, the Water and Sewer Agencies Coordination Team, and the Montana State University Local Government Center. In 2002, she received an outstanding service award from the Montana Rural Water Users Association. In addition to being considered an expert on Montana state and constitutional law, local government law and local government finance, she is a frequent teacher at the National Association of Bond Lawyers (NABL) Fundamentals of Municipal Bond Law Seminar and the NABL Bond Attorney’s Workshop. For over 30 years Mae Nan has participated in the drafting of legislation in Montana for state and local finance matters. She has served on the Board of Directors of NABL, as Chairman of its Education Committee, was elected as an initial fellow in 1995 to the American College of Bond Counsel, and was recognized as a Super Lawyer in the Rocky Mountain West. Mae Nan was admitted to practice before the MT and US Supreme Courts, was named one of “America’s Leading Business Lawyers” by Chambers USA (Rank 1), a Mountain States Super Lawyer in 2007 and is listed in Best Lawyers in America; she is a member and former Board Member of NABL, a Fellow of the American College of Bond Counsel and a member of the Board of Visitors of the UM Law School. Mae Nan is also a philanthropist who serves on boards and applies her intelligence to many organizations, such as the Missoula Art Museum. [Much of this biography was drawn from a retirement story in the Missoulian and the Dorsey Whitney web site.] Mick McKeon, born in Anaconda in 1946, is a 4th generation Montanan whose family roots in this state go back to the 1870’s. In 1968 he graduated from Notre Dame with a BA in Communications and received a Juris Doctorate degree from the University of Montana Law School in 1971. Right after graduating from law school, Mick was persuaded by his father, longtime State Senator Luke McKeon, and his uncle, Phillips County Attorney Willis McKeon, to run for delegate to Montana’s Constitutional Convention and was elected to represent Deer Lodge, Philipsburg, Powell, and part of Missoula Counties. Along with a coalition of delegates from Butte and Anaconda, he fought through the new Constitution to eliminate the legal strangle hold, often called “the copper collar,” that corporate interests -- the Anaconda Company and its business & political allies -- had over state government for nearly 100 years. The New York Times called Montana’s Constitutional Convention a “prairie revolution.” After helping secure the ratification of the new Constitution, Mick began his practice of law in Anaconda where he engaged in general practice for nearly 20 years. Moving to Butte in 1991, Mick focused has practice in personal injury law, representing victims of negligence and corporate wrongdoing in both Montana district courts and federal court. As such, he participated in some of the largest cases in the history of the state. In 1992 he and his then law partner Rick Anderson obtained a federal court verdict of $11.5 million -- the largest verdict in MT for many years. Mick’s efforts on behalf of injured victims have been recognized by many legal organizations and societies. Recently, Mick was invited to become a member of the International Academy of Trial Lawyers - 600 of the top lawyers in the world. Rated as an American Super Lawyer, he has continuously been named one of the Best Lawyers in America, and an International Assn. of Trial Lawyers top 100 Trial Lawyer. In 2005, he was placed as one of Montana’s top 4 Plaintiff’s lawyers by Law Dragon. Mick is certified as a civil trial specialist by the National Board of Trial Advocacy and has the highest rating possible from Martindale-Hubble. Mick was awarded the Montana Trial Lawyers Public Service Award and provided pro bono assistance to needy clients for his entire career. Mick’s law practice, which he now shares with his son Michael, is limited to representing individuals who have been injured in accidents, concentrating on cases against insurance companies, corporations, medical providers and hospitals. Mick resides in Butte with his wife Carol, a Butte native. Mick, Carol, Michael and another son, Matthew, who graduated from Dartmouth College and was recently admitted to the Montana bar, enjoy as much of their time together in Butte and at their place on Flathead Lake.

Infection prevention strategies in a stem cell transplant unit: impact of change of care in isolation practice and routine use of high dose intravenous immunoglobulins on infectious complications and transplant related mortality

OBJECTIVE: Nursing in 'live islands' and routine high dose intravenous immunoglobulins after allogeneic hematopoietic stem cell transplantation were abandoned by many teams in view of limited evidence and high costs. METHODS: This retrospective single-center study examines the impact of change from nursing in 'live islands' to care in single rooms (SR) and from high dose to targeted intravenous immunoglobulins (IVIG) on mortality and infection rate of adult patients receiving an allogeneic stem cell or bone marrow transplantation in two steps and three time cohorts (1993-1997, 1997-2000, 2000-2003). RESULTS: Two hundred forty-eight allogeneic hematopoetic stem cell transplantations were performed in 227 patients. Patient characteristics were comparable in the three cohorts for gender, median age, underlying disease, and disease stage, prophylaxis for graft versus host disease (GvHD) and cytomegalovirus constellation. The incidence of infections (78.4%) and infection rates remained stable (rates/1000 days of neutropenia for sepsis 17.61, for pneumonia 6.76). Cumulative incidence of GvHD and transplant-related mortality did not change over time. CONCLUSIONS: Change from nursing in 'live islands' to SR and reduction of high dose to targeted IVIG did not result in increased infection rates or mortality despite an increase in patient age. These results support the current practice.

High failure rate of trochanteric fracture osteosynthesis with proximal femoral locking compression plate

INTRODUCTION Stable reconstruction of proximal femoral (PF) fractures is especially challenging due to the peculiarity of the injury patterns and the high load-bearing requirement. Since its introduction in 2007, the PF-locking compression plate (LCP) 4.5/5.0 has improved osteosynthesis for intertrochanteric and subtrochanteric fractures of the femur. This study reports our early results with this implant. METHODS Between January 2008 and June 2010, 19 of 52 patients (12 males, 7 females; mean age 59 years, range 19-96 years) presenting with fractures of the trochanteric region were treated at the authors' level 1 trauma centre with open reduction and internal fixation using PF-LCP. Postoperatively, partial weight bearing was allowed for all 19 patients. Follow-up included a thorough clinical and radiological evaluation at 1.5, 3, 6, 12, 24, 36 and 48 months. Failure analysis was based on conventional radiological and clinical assessment regarding the type of fracture, postoperative repositioning, secondary fracture dislocation in relation to the fracture constellation and postoperative clinical function (Merle d'Aubigné score). RESULTS In 18 patients surgery achieved adequate reduction and stable fixation without intra-operative complications. In one patient an ad latus displacement was observed on postoperative X-rays. At the third month follow-up four patients presented with secondary varus collapse and at the sixth month follow-up two patients had 'cut-outs' of the proximal fragment, with one patient having implant failure due to a broken proximal screw. Revision surgeries were performed in eight patients, one patient receiving a change of one screw, three patients undergoing reosteosynthesis with implantation of a condylar plate and one patient undergoing hardware removal with secondary implantation of a total hip prosthesis. Eight patients suffered from persistent trochanteric pain and three patients underwent hardware removal. CONCLUSIONS Early results for PF-LCP osteosynthesis show major complications in 7 of 19 patients requiring reosteosynthesis or prosthesis implantation due to secondary loss of reduction or hardware removal. Further studies are required to evaluate the limitations of this device.

STUDIES ON THE PATTERNS OF NUCLEOTIDE AND AMINO ACID SUBSTITUTION (ELECTROPHORESIS, MUTATION RATE, SELECTION, BASE, COMPOSITION)

Theoretical and empirical studies were conducted on the pattern of nucleotide and amino acid substitution in evolution, taking into account the effects of mutation at the nucleotide level and purifying selection at the amino acid level. A theoretical model for predicting the evolutionary change in electrophoretic mobility of a protein was also developed by using information on the pattern of amino acid substitution. The specific problems studied and the main results obtained are as follows: (1) Estimation of the pattern of nucleotide substitution in DNA nuclear genomes. The pattern of point mutations and nucleotide substitutions among the four different nucleotides are inferred from the evolutionary changes of pseudogenes and functional genes, respectively. Both patterns are non-random, the rate of change varying considerably with nucleotide pair, and that in both cases transitions occur somewhat more frequently than transversions. In protein evolution, substitution occurs more often between amino acids with similar physico-chemical properties than between dissimilar amino acids. (2) Estimation of the pattern of nucleotide substitution in RNA genomes. The majority of mutations in retroviruses accumulate at the reverse transcription stage. Selection at the amino acid level is very weak, and almost non-existent between synonymous codons. The pattern of mutation is very different from that in DNA genomes. Nevertheless, the pattern of purifying selection at the amino acid level is similar to that in DNA genomes, although selection intensity is much weaker. (3) Evaluation of the determinants of molecular evolutionary rates in protein-coding genes. Based on rates of nucleotide substitution for mammalian genes, the rate of amino acid substitution of a protein is determined by its amino acid composition. The content of glycine is shown to correlate strongly and negatively with the rate of substitution. Empirical formulae, called indices of mutability, are developed in order to predict the rate of molecular evolution of a protein from data on its amino acid sequence. (4) Studies on the evolutionary patterns of electrophoretic mobility of proteins. A theoretical model was constructed that predicts the electric charge of a protein at any given pH and its isoelectric point from data on its primary and quaternary structures. Using this model, the evolutionary change in electrophoretic mobilities of different proteins and the expected amount of electrophoretically hidden genetic variation were studied. In the absence of selection for the pI value, proteins will on the average evolve toward a mildly basic pI. (Abstract shortened with permission of author.) ^

Flower and seed biomass, and germination rate of arctic tundra plants in response to long term experimental warming

We provide new information on changes in tundra plant sexual reproduction in response to long-term (12 years) experimental warming in the High Arctic. Open-top chambers (OTCs) were used to increase growing season temperatures by 1-2 °C across a range of vascular plant communities. The warming enhanced reproductive effort and success in most species; shrubs and graminoids appeared to be more responsive than forbs. We found that the measured effects of warming on sexual reproduction were more consistently positive and to a greater degree in polar oasis compared with polar semidesert vascular plant communities. Our findings support predictions that long-term warming in the High Arctic will likely enhance sexual reproduction in tundra plants, which could lead to an increase in plant cover. Greater abundance of vegetation has implications for primary consumers - via increased forage availability, and the global carbon budget - as a function of changes in permafrost and vegetation acting as a carbon sink. Enhanced sexual reproduction in Arctic vascular plants may lead to increased genetic variability of offspring, and consequently improved chances of survival in a changing environment. Our findings also indicate that with future warming, polar oases may play an important role as a seed source to the surrounding polar desert landscape.