EuroGuiderm guideline on lichen sclerosus-introduction into lichen sclerosus.

INTRODUCTION: Lichen sclerosus (LS) is an inflammatory skin disease affecting all ages. LS typically involves the anogenital site where it causes itching and soreness. It may lead to sexual and urinary dysfunction in females and males; however, it may be asymptomatic. First signs of LS are redness and oedema, typically followed by whitening of the genital skin; sometimes fissuring, scarring, shrinkage and fusion of structures may follow in its course. LS is associated with an increased risk of genital cancer. LS has a huge impact on the quality of life of affected patients, and it is important to raise more awareness of this not uncommon disease in order to diagnose and treat it early. OBJECTIVES: The guideline intends to provide guidance on the diagnostic of LS, highlight important aspects in the care of LS patients (part 1), generate recommendations and treatment algorithms (part 2) on topical, interventional and surgical therapy, based on the latest evidence, provide guidance in the management of LS patients during pregnancy, provide guidance for the follow-up of patients with LS and inform about new developments and potential research aspects. MATERIALS AND METHODS: The guideline was developed in accordance with the EuroGuiDerm Methods Manual v1.3 https://www.edf.one/de/home/Guidelines/EDF-EuroGuiDerm.html. The wording of the recommendations was standardized (as suggested by the GRADE Working Group). The guideline development group is comprised of 34 experts from 16 countries, including 5 patient representatives. RESULTS: Ultrapotent or potent topical corticosteroids in females and males, adults and children remain gold standard of care for genital LS; co-treatment with emollients is recommended. If standard treatment fails in males, a surgical intervention is recommended, complete circumcision may cure LS in males. UV light treatment is recommended for extragenital LS; however, there is limited scientific evidence. Topical calcineurin inhibitors are second line treatment. Laser treatment, using various wave lengths, is under investigation, and it can currently not be recommended for the treatment of LS. Treatment with biologics is only reported in single cases. CONCLUSIONS: LS has to be diagnosed and treated as early as possible in order to minimize sequelae like scarring and cancer development. Topical potent and ultrapotent corticosteroids are the gold standard of care; genital LS is often a lifelong disease and needs to be treated long-term.

EuroGuiderm guideline on lichen sclerosus-Treatment of lichen sclerosus.

INTRODUCTION: Lichen sclerosus (LS) is an inflammatory skin disease affecting all ages. LS typically involves the anogenital site where it causes itching and soreness; it may lead to sexual and urinary dysfunction in females and males; however, it may be asymptomatic. First signs of LS are usually a whitening of the genital skin, sometimes preceded by redness and oedema; fissuring, scarring, shrinkage and fusion of structures may follow in its course. LS is associated with an increased risk of genital cancer. LS has a huge impact on the quality of life of affected patients, and it is important to raise more awareness of this not uncommon disease in order to diagnose and treat it early. OBJECTIVES: The guideline intends to provide guidance on the diagnostic of LS (part 1), highlight important aspects in the care of LS patients, generate recommendations and treatment algorithms (part 2) on topical, interventional and surgical therapy, based on the latest evidence, provide guidance in the management of LS patients during pregnancy, provide guidance for the follow-up of patients with LS and inform about new developments and potential research aspects. MATERIALS AND METHODS: The guideline was developed in accordance with the EuroGuiDerm Methods Manual v1.3 https://www.edf.one/de/home/Guidelines/EDF-EuroGuiDerm.html. The wording of the recommendations was standardized (as suggested by the GRADE Working Group). The guideline development group is comprised of 34 experts from 16 countries, including 5 patient representatives. RESULTS: Ultrapotent or potent topical corticosteroids in females and males, adults and children remain gold standard of care for genital LS; co-treatment with emollients is recommended. If standard treatment fails in males, a surgical intervention is recommended, complete circumcision may cure LS in males. UV light treatment is recommended for extragenital LS; however, there is limited scientific evidence. Topical calcineurin inhibitors are second line treatment. Laser treatment, using various wave lengths, is under investigation, and it can currently not be recommended for the treatment of LS. Treatment with biologics is only reported in single cases. CONCLUSIONS: LS has to be diagnosed and treated as early as possible in order to minimize sequelae like scarring and cancer development. Topical potent and ultrapotent corticosteroids are the gold standard of care; genital LS is often a lifelong disease and needs to be treated long-term.

The complex circumstellar environment of supernova 2023ixf.

The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare1,2, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating3. Early serendipitous observations2,4 that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN 2023ixf in the galaxy Messier 101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.

Ethnic differences in normal electrocardiographic findings in elite brazilian football players: b-pro foot ECG pilot study

INTRODUCTION: The 12-lead electrocardiogram (ECG-12) is a useful tool in the assessment of athletes. The prevalence of normal electrocardiographic findings in elite Brazilian football players (EBFP) of different ethnicities is not well described. PURPOSE: To compare the prevalence of normal ECG-12 findings in Caucasian, Mixed-race (MR), and Afro-Brazilian (AB) EBFP. METHODS: A multicenter cross-sectional descriptive study was conducted with exams performed on EBFP as a pre-participation assessment from February 18, 2002, through October 20, 2022. RESULTS: 4,363 EBFP from 51 professional clubs (from all five regions of Brazil; 15 states, and 21 cities), aged 15-35 years (median: 19 years; IQR: 16-23) were evaluated. 2,027 were Caucasians, 1,324 were MRs, and 1,012 were ABs. In general, we recorded 4,155 ECG-12 with normal variations (95.2%). Positive Sokolow-Lyon criteria for left ventricular hypertrophy was more prevalent in ABs (41.8%) than in Caucasians (33.4%), or MRs (32.7%). The prevalence of early repolarization in ABs (41.5%) was higher than in Caucasians (34.6%), or MRs (35.5%). The PR interval was longer in ABs (157.1 ms) than in Caucasians (151.4 ms), or MRs (153.3 ms), and the first-degree atrioventricular block was more frequent in ABs compared to MRs (4.2% vs. 2.3%, respectively). On the other hand, Caucasians had a higher prevalence of incomplete right bundle branch block (14.2%) than MRs (11.2%), or ABs (9.7%). In our sample, only three EBFP showed second-degree atrioventricular block Mobitz type I (0.07%; one Caucasian and two AB athletes). CONCLUSIONS: This is the first large study to compare the prevalence of ECG-12 findings in EBFP from different ethnic groups. Those of AB origin have a significantly higher prevalence of ECG-12 findings compatible with the athlete's heart than Caucasians and MRs.

Peroperative extent of peritoneal metastases affects the surgical outcome and survival in advanced ovarian cancer.

OBJECTIVE: Determining whether cytoreductive surgery (CRS) is feasible in patients with advanced ovarian cancer and whether extensive surgery is justified is challenging. Accurate patient selection for CRS based on pre- and peroperative parameters will be valuable. The aim of this study is to assess the association between the extent of peritoneal metastases as determined during surgery and completeness of interval CRS and survival. METHODS: This single-center observational cohort study included consecutive patients with newly diagnosed stage III-IV epithelial ovarian cancer who received neoadjuvant chemotherapy and underwent interval CRS. The 7 Region Count (7RC) was recorded during surgical exploration to systematically quantify the extent of peritoneal metastases. Logistic regression analysis was performed to predict surgical outcomes, and Cox regression analysis was done for survival outcomes. RESULTS: A total of 316 patients were included for analyses. The median 7RC was 4 (interquartile range: 2-6). Complete CRS was performed in 58%, optimal CRS in 30%, and incomplete CRS in 12% of patients. A higher 7RC was independently associated with lower odds of complete or optimal CRS in multivariable analysis (odds ratio [OR] = 0.45, 95% confidence interval [CI]: 0.33-0.63, p < 0.001). Similarly, a higher 7RC was independently associated with worse progression-free survival (hazard ratio [HR] = 1.17, 95% CI 1.08-1.26, p < 0.001) and overall survival (HR = 1.14, 95% CI 1.04-1.25, p = 0.007). CONCLUSION: The extent of peritoneal metastases, as expressed by the 7RC during surgery, is an independent predictor for completeness of CRS and has independent prognostic value for progression-free survival and overall survival in addition to completeness of CRS.

[German guideline on undescended testis-what is relevant in daily routine?] / Praxisrelevantes aus der S2k-Leitlinie Hodenhochstand ­ Malsdescensus testis.

With an incidence of 0.7-3% in male infants, undescended testicles is one of the most common congenital anomalies. In the first 6 months of life, the testicles may spontaneously descend in up to 70% of individuals. If the testicle is not in a scrotal position afterwards, fertility can gradually be reduced and the risk of a testicular tumor increases. Therefore, the current German guideline for undescended testis recommends that therapy should be take place between 6 and 12 months of life. After extensive information on the advantages and disadvantages, hormone therapy with the aim of a descensus or in those with bilateral anomaly with the aim of improving the germ cell pool can be offered. After the first year of life, hormone therapy is obsolete. Otherwise, surgical intervention is the treatment of choice. In the case of gliding or deep inguinal testis via scrotal or inguinal access, in the case of nonpalpable and sonographically undetectable testis, laparoscopy is carried out for diagnosis and simultaneous therapy. In the first postoperative year, adequate follow-up should be done to detect a re-ascensus and/or insufficient growth. Regular self-examinations from the age of 15 serve for the early detection of a testicular tumor that occurs only very rarely (approximately 0.003%).

Molecular and ecological plant defense responses along an elevational gradient in a boreal ecosystem.

Plants have the capacity to alter their phenotype in response to environmental factors, such as herbivory, a phenomenon called phenotypic plasticity. However, little is known on how plant responses to herbivory are modulated by environmental variation along ecological gradients. To investigate this question, we used bilberry (Vaccinium myrtillus L.) plants and an experimental treatment to induce plant defenses (i.e., application of methyl jasmonate; MeJA), to observe ecological responses and gene expression changes along an elevational gradient in a boreal system in western Norway. The gradient included optimal growing conditions for bilberry in this region (ca. 500 m a.s.l.), and the plant's range limits at high (ca. 900 m a.s.l.) and low (100 m a.s.l.) elevations. Across all altitudinal sites, MeJA-treated plants allocated more resources to herbivory resistance while reducing growth and reproduction than control plants, but this response was more pronounced at the lowest elevation. High-elevation plants growing under less herbivory pressure but more resource-limiting conditions exhibited consistently high expression levels of defense genes in both MeJA-treated and untreated plants at all times, suggesting a constant state of "alert." These results suggest that plant defense responses at both the molecular and ecological levels are modulated by the combination of climate and herbivory pressure, such that plants under different environmental conditions differentially direct the resources available to specific antiherbivore strategies. Our findings are important for understanding the complex impact of future climate changes on plant-herbivore interactions, as this is a major driver of ecosystem functioning and biodiversity.

["Uncomplicated" inguinal testis : How practicable are the guidelines?] / Der "unkomplizierte" Leistenhoden : Wie praktikabel sind die Leitlinien?

It has been known for more than 20 years that early treatment of maldescended testicles can have a positive effect on fertility and a negative effect on the development of tumors. In certain circumstances, hormone therapy is still recommended in German-speaking countries. However, its benefit is still controversially discussed. Therapy is usually initiated by the pediatrician, who is usually the first to detect undescended testicles. Since therapy may involve early hormone therapy as well as surgery, acceptance among pediatricians and also the parents may be reduced. The question also arises as to how far the implementation is practicable. In patients with nonpalpable testis, there are many controversies concerning the value of ultrasound investigations. In the following two case studies, the treatment decisions for undescended testes in infancy are exemplified. Furthermore, the available evidence from the literature and guidelines is presented to provide assistance for daily routine care and to critically discuss potential fields of application and limitations of existing guidelines.

[Testicular tumors in prepubertal boys-organ preservation possible more often than expected]. / Hodentumoren bei präpubertären Jungen ­ Organerhalt häufiger möglich als gedacht.

In prepubertal boys, testicular tumors are rare with an incidence between 2 and 5/million. In contrast to testicular tumors in adolescents and adults, more than 2/3 of these tumors are benign. Unfortunately, in Germany in most cases, only malignant tumors (usually yolk sac tumors) are reported to the study center (MAKEI IV and now V). Therefore, the incidence in Germany is unknown. Since the introduction of polychemotherapy in the 1970s, the prognosis of malignant testicular tumors has improved enormously and has become a curable disease, even in the case of recurrence. Today the orchiectomy, which was usually carried out in the past, appears to be no longer justified in most prepubertal boys due to the high incidence of benign tumors. It has been shown in various studies that organ-sparing surgery in germ cell tumors (epidermoid cysts, teratoma); gonadal stoma tumors (Sertoli, Leydig and granulosa cell tumors) and cystic lesions (intratesticular cysts and tubular ectasia of the rete testis) is reliable and safe. In cases with preoperative significantly increased AFP (caution: norm values not valid in the first year of life) and a clear testicular tumor in the ultrasound (yolk sac tumor) or if no testicular parenchyma is sonographically detectable, orchiectomy can still be carried out. Today orchiectomies in prepubertal boys should be an exception and the reasons for an orchiectomy must be well documented.

Strategies to Improve Recruitment to a De-escalation Trial: A Mixed-Methods Study of the OPTIMA Prelim Trial in Early Breast Cancer.

AIMS: De-escalation trials are challenging and sometimes may fail due to poor recruitment. The OPTIMA Prelim randomised controlled trial (ISRCTN42400492) randomised patients with early stage breast cancer to chemotherapy versus 'test-directed' chemotherapy, with a possible outcome of no chemotherapy, which could confer less treatment relative to routine practice. Despite encountering challenges, OPTIMA Prelim reached its recruitment target ahead of schedule. This study reports the root causes of recruitment challenges and the strategies used to successfully overcome them. MATERIALS AND METHODS: A mixed-methods recruitment intervention (QuinteT Recruitment Intervention) was used to investigate the recruitment difficulties and feedback findings to inform interventions and optimise ongoing recruitment. Quantitative site-level recruitment data, audio-recorded recruitment appointments (n = 46), qualitative interviews (n = 22) with trialists/recruiting staff (oncologists/nurses) and patient-facing documentation were analysed using descriptive, thematic and conversation analyses. Findings were triangulated to inform a 'plan of action' to optimise recruitment. RESULTS: Despite best intentions, oncologists' routine practices complicated recruitment. Discomfort about deviating from the usual practice of recommending chemotherapy according to tumour clinicopathological features meant that not all eligible patients were approached. Audio-recorded recruitment appointments revealed how routine practices undermined recruitment. A tendency to justify chemotherapy provision before presenting the randomised controlled trial and subtly indicating that chemotherapy would be more/less beneficial undermined equipoise and made it difficult for patients to engage with OPTIMA Prelim. To tackle these challenges, individual and group recruiter feedback focussed on communication issues and vignettes of eligible patients were discussed to address discomforts around approaching patients. 'Tips' documents concerning structuring discussions and conveying equipoise were disseminated across sites, together with revisions to the Patient Information Sheet. CONCLUSIONS: This is the first study illuminating the tension between oncologists' routine practices and recruitment to de-escalation trials. Although time and resources are required, these challenges can be addressed through specific feedback and training as the trial is underway.

[Update of the 2Sk guidelines on the diagnostics, treatment and metaphylaxis of urolithiasis (AWMF register number 043-025) : What is new?] / Aktualisierung der S2k-Leitlinie zur Diagnostik, Therapie und Metaphylaxe der Urolithiasis (AWMF Registernummer 043-025) : Was ist neu?

The increase of medical knowledge and technical innovations together with the demographic change represent a challenge for the new conception of guidelines and clinical studies. The present S2k guidelines, which are exclusively concerned with kidney and ureteral stones, should support the treatment of urolithiasis in hospitals and private practices and provide information on urolithiasis for patients. Increasing interdisciplinary collaboration in stone treatment is also demonstrated in the number of professional and working groups participating in the update of the new guidelines. The present S2k guidelines emerged from a consensus process and demonstrate the current recommendations in step with actual practice. They provide decision-making guidance for diagnostics, treatment and metaphylactic measures based on expert opinions and available published fundamental evidence from the literature.

Univariate Community Assembly Analysis (UniCAA): Combining hierarchical models with null models to test the influence of spatially restricted dispersal, environmental filtering, and stochasticity on community assembly.

Identifying the influence of stochastic processes and of deterministic processes, such as dispersal of individuals of different species and trait-based environmental filtering, has long been a challenge in studies of community assembly. Here, we present the Univariate Community Assembly Analysis (UniCAA) and test its ability to address three hypotheses: species occurrences within communities are (a) limited by spatially restricted dispersal; (b) environmentally filtered; or (c) the outcome of stochasticity-so that as community size decreases-species that are common outside a local community have a disproportionately higher probability of occurrence than rare species. The comparison with a null model allows assessing if the influence of each of the three processes differs from what one would expect under a purely stochastic distribution of species. We tested the framework by simulating "empirical" metacommunities under 15 scenarios that differed with respect to the strengths of spatially restricted dispersal (restricted vs. not restricted); habitat isolation (low, intermediate, and high immigration rates); and environmental filtering (strong, intermediate, and no filtering). Through these tests, we found that UniCAA rarely produced false positives for the influence of the three processes, yielding a type-I error rate ≤5%. The type-II error rate, that is, production of false negatives, was also acceptable and within the typical cutoff (20%). We demonstrate that the UniCAA provides a flexible framework for retrieving the processes behind community assembly and propose avenues for future developments of the framework.

Variations of sex development: The first German interdisciplinary consensus paper.

INTRODUCTION: The term variations of sex development subsumes a large number of congenital conditions including chromosomal mosaics and variations of chromosomal, gonadal, and phenotypic sex. A situation of this nature may cause severe distress to both, parents and affected persons. One of the reasons for this is the binary form of gender classification in the society. In the past, because of a fear of possible stigmatization and an inability to cope with complex situations, it has been medical policy and practice for newborns to undergo early, mostly 'feminizing' elective surgery with the aim of achieving an outer genital appearance that is unambiguously male or female. Protests by advocacy groups for the most part as well as the results of outcome studies have shown that the development of affected persons may be very different to what has been expected and often does not result in the intended clear female or male gender identity as had been intended. It, therefore, seemed a matter of urgency to implement this new awareness as well as the ethical and personal human rights perspectives in the recommendations for the medical and psychosocial management of diverse sex development (DSD) in the future. STUDY DESIGN: In 2012, an interdisciplinary group of German academics engaged in the field of DSD decided to work on a consensus paper for this topic. It involved the participation of all faculties and non-scientific groups dealing with DSD, in particular advocacy and service-user groups. In a structured consensus, process recommendations were developed based on scientific literature as well as personal experiences of clinicians and affected individuals. RESULTS: Finally, 37 recommendations were agreed on. The strength of consensus is reflected in the degree of agreement as expressed in percentages. CONCLUSION: The introduction of the consensus paper reflects on the emerging paradigm shift and the necessity for a more open view of gender within society. The paper is intended to aid the performance of appropriate diagnostics in DSD-affected newborns and especially to help parents and affected persons cope with the biological and social consequences of DSD. With regard to medical or surgical therapy, it gives information about the most recent treatment trends.

Home and neighbourhood built environment features in family-based treatment for childhood obesity.

BACKGROUND: Family-based behavioural weight loss treatment (FBT) for childhood obesity helps families develop strategies to facilitate healthy choices in their home and other environments (e.g. home neighbourhood). The current study examines how the home food environment, both pre-FBT and post-FBT, and the neighbourhoods in which families live are associated with child weight and weight-related outcomes in FBT. METHODS: Parent-child dyads (n = 181) completed a 16-session FBT programme and completed home environment, anthropometric and child dietary/activity assessments at pre-FBT and post-FBT. Parents reported on availability of food, electronics and physical activity equipment in the home. The neighbourhood food and recreation environments around each dyad's residence was characterized using existing data within a geographic information system. RESULTS: Families successfully made healthy home environment modifications during FBT. Regression models showed reducing RED (e.g. high-energy-dense and low-nutrient-dense) foods and electronics in the home during FBT had positive effects on child weight and weight-related outcomes. No neighbourhood food or recreation environment variables were significantly related to outcomes, although having a larger density of public recreation spaces was associated with increases in physical activity at the trend-level. CONCLUSIONS: Modifying the home environment, specifically reducing RED foods and electronics, may be particularly important for FBT success.

Multiannual effects of induced plant defenses: Are defended plants good or bad neighbors?

Defenses induced by herbivore feeding or phytohormones such as methyl jasmonate (MeJA) can affect growth, reproduction, and herbivory, not only on the affected individual but also in its neighboring plants. Here, we report multiannual defense, growth, and reproductive responses of MeJA-treated bilberry (Vaccinium myrtillus) and neighboring ramets. In a boreal forest in western Norway, we treated bilberry ramets with MeJA and water (control) and measured responses over three consecutive years. We observed the treatment effects on variables associated with herbivory, growth, and reproduction in the MeJA-treated and untreated ramet and neighboring ramets distanced from 10 to 500 cm. MeJA-treated ramets had fewer grazed leaves and browsed shoots compared to control, with higher effects in 2014 and 2015, respectively. In 2013, growth of control ramets was greater than MeJA-treated ramets. However, MeJA-treated ramets had more flowers and berries than control ramets 2 years after the treatment. The level of insect and mammalian herbivory was also lower in untreated neighboring ramets distanced 10-150 cm and, consistent with responses of MeJA-treated ramets, the stronger effect was also one and 2 years delayed, respectively. The same neighboring ramets had fewer flowers and berries than untreated ramets, indicating a trade-off between defense and reproduction. Although plant-plant effects were observed across all years, the strength varied by the distance between the MeJA-treated ramets and its untreated neighbors. We document that induced defense in bilberry reduces both insect and mammalian herbivory, as well as growth, over multiple seasons. The defense responses occurred in a delayed manner with strongest effects one and 2 years after the induction. Additionally, our results indicate defense signaling between MeJA-treated ramets and untreated neighbors. In summary, this study shows that induced defenses are important ecological strategies not only for the induced individual plant but also for neighboring plants across multiple years in boreal forests.

North Pacific freshwater events linked to changes in glacial ocean circulation.

There is compelling evidence that episodic deposition of large volumes of freshwater into the oceans strongly influenced global ocean circulation and climate variability during glacial periods1,2. In the North Atlantic region, episodes of massive freshwater discharge to the North Atlantic Ocean were related to distinct cold periods known as Heinrich Stadials1-3. By contrast, the freshwater history of the North Pacific region remains unclear, giving rise to persistent debates about the existence and possible magnitude of climate links between the North Pacific and North Atlantic oceans during Heinrich Stadials4,5. Here we find that there was a strong connection between changes in North Atlantic circulation during Heinrich Stadials and injections of freshwater from the North American Cordilleran Ice Sheet to the northeastern North Pacific. Our record of diatom δ18O (a measure of the ratio of the stable oxygen isotopes 18O and 16O) over the past 50,000 years shows a decrease in surface seawater δ18O of two to three per thousand, corresponding to a decline in salinity of roughly two to four practical salinity units. This coincided with enhanced deposition of ice-rafted debris and a slight cooling of the sea surface in the northeastern North Pacific during Heinrich Stadials 1 and 4, but not during Heinrich Stadial 3. Furthermore, results from our isotope-enabled model6 suggest that warming of the eastern Equatorial Pacific during Heinrich Stadials was crucial for transmitting the North Atlantic signal to the northeastern North Pacific, where the associated subsurface warming resulted in a discernible freshwater discharge from the Cordilleran Ice Sheet during Heinrich Stadials 1 and 4. However, enhanced background cooling across the northern high latitudes during Heinrich Stadial 3-the coldest period in the past 50,000 years7-prevented subsurface warming of the northeastern North Pacific and thus increased freshwater discharge from the Cordilleran Ice Sheet. In combination, our results show that nonlinear ocean-atmosphere background interactions played a complex role in the dynamics linking the freshwater discharge responses of the North Atlantic and North Pacific during glacial periods.

Tree seed rain and seed removal, but not the seed bank, impede forest recovery in bracken (Pteridium aquilinum (L.) Kuhn)-dominated clearings in the African highlands.

Considerable areas dominated by bracken Pteridium aquilinum (L.) Kuhn occur worldwide and are associated with arrested forest recovery. How forest recovery is impeded in these areas remains poorly understood, especially in the African highlands. The component processes that can lead to recruitment limitation-including low seed arrival, availability and persistence-are important determinants of plant communities and offer a potential explanation for bracken persistence. We investigated key processes that can contribute to recruitment limitation in bracken-dominated clearings in the Bwindi Impenetrable National Park, Uganda. We examined if differences in seed rain (dispersal limitation), soil seed bank, or seed removal (seed viability and persistence) can, individually or in combination, explain the differences in tree regeneration found between bracken-dominated areas and the neighboring forest. These processes were assessed along ten 50-m transects crossing the forest-bracken boundary. When compared to the neighboring forest, bracken clearings had fewer seedlings (bracken 11,557 ± 5482 vs. forest 34,515 ± 6066 seedlings/ha), lower seed rain (949 ± 582 vs. 1605 ± 335 tree seeds m-2 year-1), comparable but sparse soil seed bank (304 ± 236 vs. 264 ± 99 viable tree seeds/m2), higher seed removal (70.1% ± 2.4% vs. 40.6% ± 2.4% over a 3-day interval), and markedly higher rodent densities (25.7 ± 5.4 vs. 5.0 ± 1.6 rodents per 100 trapping sessions). Camera traps revealed that rodents were the dominant animals visiting the seeds in our seed removal study. Synthesis: Recruitment limitation contributes to both the slow recovery of forest in bracken-dominated areas, and to the composition of the tree species that occur. Low seed arrival and low persistence of unburied seeds can both explain the reduced density of seedlings found in bracken versus neighboring forest. Seed removal, likely due to rodents, in particular appears sufficient to constrain forest recovery and impacts some species more severely than others.

Global priorities for conserving the evolutionary history of sharks, rays and chimaeras.

In an era of accelerated biodiversity loss and limited conservation resources, systematic prioritization of species and places is essential. In terrestrial vertebrates, evolutionary distinctness has been used to identify species and locations that embody the greatest share of evolutionary history. We estimate evolutionary distinctness for a large marine vertebrate radiation on a dated taxon-complete tree for all 1,192 chondrichthyan fishes (sharks, rays and chimaeras) by augmenting a new 610-species molecular phylogeny using taxonomic constraints. Chondrichthyans are by far the most evolutionarily distinct of all major radiations of jawed vertebrates-the average species embodies 26 million years of unique evolutionary history. With this metric, we identify 21 countries with the highest richness, endemism and evolutionary distinctness of threatened species as targets for conservation prioritization. On average, threatened chondrichthyans are more evolutionarily distinct-further motivating improved conservation, fisheries management and trade regulation to avoid significant pruning of the chondrichthyan tree of life.