Giant magnetocaloric effect in a rare-earth-free layered coordination polymer at liquid hydrogen temperatures.

Magnetic refrigeration, which utilizes the magnetocaloric effect, can provide a viable alternative to the ubiquitous vapor compression or Joule-Thompson expansion methods of refrigeration. For applications such as hydrogen gas liquefaction, the development of magnetocaloric materials that perform well in moderate magnetic fields without using rare-earth elements is highly desirable. Here we present a thorough investigation of the structural and magnetocaloric properties of a novel layered organic-inorganic hybrid coordination polymer Co4(OH)6(SO4)2[enH2] (enH2 = ethylenediammonium). Heat capacity, magnetometry and direct adiabatic temperature change measurements using pulsed magnetic fields reveal a field-dependent ferromagnetic second-order phase transition at 10 K < T C < 15 K. Near the hydrogen liquefaction temperature and in a magnetic field change of 1 T, a large maximum value of the magnetic entropy change, Δ S M P k = - 6.31 J kg-1 K-1, and an adiabatic temperature change, Δ T ad = 1.98 K, are observed. These values are exceptional for rare-earth-free materials and competitive with many rare-earth-containing alloys that have been proposed for magnetic cooling around the hydrogen liquefaction range.

Ghost Channels and Ghost Cycles Guiding Long Transients in Dynamical Systems.

Dynamical descriptions and modeling of natural systems have generally focused on fixed points, with saddles and saddle-based phase-space objects such as heteroclinic channels or cycles being central concepts behind the emergence of quasistable long transients. Reliable and robust transient dynamics observed for real, inherently noisy systems is, however, not met by saddle-based dynamics, as demonstrated here. Generalizing the notion of ghost states, we provide a complementary framework that does not rely on the precise knowledge or existence of (un)stable fixed points, but rather on slow directed flows organized by ghost sets in ghost channels and ghost cycles. Moreover, we show that the appearance of these novel objects is an emergent property of a broad class of models typically used for description of natural systems.

[Comparison of the reoperation rates of three techniques for tibial tuberosity transposition in medial patellar dislocation]. / Vergleich der Reoperationsraten von drei Techniken zur Fixation der bei medialer Patellaluxation transponierten Tuberositas tibiae.

INTRODUCTION: A common technique for the treatment of medial patellar luxation is the lateral transposition of the tibial tuberosity. Two variations of a new surgical method with a retention plate and fixation with a wire or a security plate, were tested against each other and against the existing fixation with Kirschner wires and a tension band by the number of reoperations. The new method using a retention plate and security plate showed the lowest rate of reoperations (5 %), followed by the new technique using retention plate and wire (14 %) and the existing fixation with Kirschner wires and a tension band (34 %). A possible explanation for the good result of the new method can be the fixation of the implants on the medial side of the tibia and the non-use of Kirschner wires.

INTRODUCTION: La transposition latérale de la tubérosité tibiale est une technique courante pour le traitement de la luxation rotulienne médiale. Deux variantes d'une nouvelle méthode chirurgicale avec une plaque de rétention et une fixation avec un fil métallique respectivement un étrier en titane ont été testées l'une par rapport à l'autre et par rapport à la fixation usuelle avec des broches de Kirschner et un haubanage en fonction du nombre de réopérations. La nouvelle méthode utilisant une plaque de rétention et un étrier a montré le taux le plus bas de réopérations (5 %), suivie par la nouvelle technique utilisant une plaque de rétention et une broche (14 %) et la fixation usuelle avec des broches de Kirschner et un haubanage (34 %). Le bon résultat de la nouvelle méthode peut s'expliquer par la fixation des implants sur la face médiale du tibia et la non-utilisation de broches de Kirschner.

In-vitro model to mimic T cell subset change in human PDAC organoid co-culture.

PURPOSE: Immunotherapies have largely failed as treatment options for pancreatic ductal adenocarcinoma (PDAC). In this field, clinical translational studies into personalized treatment are of fundamental importance. In our study, we model tumor-cell immune-cell interactions in a co-culture of primary human PDAC organoids and matched peripheral blood mononuclear cells (PBMCs). METHODS: Using flow cytometry, we evaluated changes in T cell subtypes upon co-culture of patient-derived PDAC organoids and matched PBMCs. RESULTS: After co-culturing PDAC organoids with PBMCs, we observed changes in CD4+, CD8+ and Treg cell populations. We observed favorable clinical outcome in patients whose PBMCs reacted to the co-culture with organoids. CONCLUSION: This experimental model allows to investigate interactions between patient derived PDAC organoids and their PBMCs. This co-culture system could serve as a preclinical platform to guide personalized therapeutic strategies in the future.

Comparison of four methods to -determine cage width in tibial tuberosity advancement.

INTRODUCTION: The objective of this study was to test a method for determining the width of the tibial tuberosity advancement (TTA) cage without the need for extension of the stifle joint, while producing preoperative radiographs. TTA cage size was determined by applying 4 different methods using radiograph images in mediolateral direction of fully extended stifles of dogs (n=43), with and without naturally occurring cranial cruciate ligament disease: parallel shift (PS) method, common tangent (CT) method, «2,1¼ method (cage size = 2,1 × tibia plateau length - tibial tuberosity width), and margo cranialis (MC) method (cage size = length of MC/6*1,75). Two new methods, «2,1¼, and MC were compared to the existing CT and PS methods. All 4 methods resulted in reliable cage sizes. Intraclass correlation coefficients showed an excellent reliability of the CT and PS to the «2,1¼ method and a good reliability in regards to the MC method. In conclusion, TTA cage size of the tibia anatomy alone can be determined on radiographs without the need of full extension of the stifle joint. Based on the results, two different methods of cage size measurement are recommended in order to increase diagnostic accuracy and to prevent the insertion of suboptimal cages.

INTRODUCTION: L'objectif de cette étude était de tester une méthode pour déterminer la largeur de la cage d'avancement de la tubérosité tibiale (TTA) sans avoir besoin d'extension du grasset, tout en réalisant des radiographies préopératoires. La taille de la cage TTA a été déterminée en appliquant 4 méthodes différentes, utilisant des images radiographiques dans l'axe médiolatéral des grassets complètement étendus de chiens (n ​​= 43), avec et sans pathologie naturelle du ligament croisé antérieur: méthode du décalage parallèle (PS), méthode de la tangente commune (CT), méthode «2,1¼ (taille de la cage = 2,1 × longueur du plateau du tibia ­ largeur de la tubérosité tibiale) et méthode de la margo cranialis (MC) (taille de la cage = longueur de MC/6*1,75). Deux nouvelles méthodes, «2,1¼ et MC ont été comparées aux méthodes CT et PS existantes. Les 4 méthodes ont abouti à des tailles de cage fiables. Les coefficients de corrélation intra classe ont montré une excellente fiabilité du CT et du PS avec la méthode «2,1¼ et une bonne fiabilité vis-à-vis de la méthode MC. En conclusion, la taille de la cage TTA de l'anatomie du tibia seule peut être déterminée sur des radiographies sans qu'il soit nécessaire d'étendre complètement l'articulation du grasset. Sur la base des résultats, deux méthodes différentes de mesure de la taille des cages sont recommandées afin d'augmenter la précision du diagnostic et d'empêcher la mise en place de cages sous-optimales.

The Future Is Female (and Behavior Analysis): A Behavioral Account of Sexism and How Behavior Analysis Is Simultaneously Part of the Problem and Solution.

In 2015, females accounted for 82.2% of Board Certified Behavior Analysts (Nosik & Grow, 2015, "Prominent Women in Behavior Analysis: An Introduction," The Behavior Analyst, 38, 225-227). Females represent most certificants, yet their presence in research and on editorial boards for peer-reviewed journals is lower than males' presence (Li, Curiel, Pritchard, & Poling, 2018, "Participation of Women in Behavior Analysis Research: Some Recent and Relevant Data," Behavior Analysis in Practice, 11, 160-164). Various contingencies are certainly involved, which may include instances of sexism or gender-based discrimination. Despite behavior analysis having the means to change contingencies that reinforce sexism, the discipline is not adequately taking cultural contingencies into consideration. As a result, behavior analysis is simultaneously part of the problem and the potential solution. Moreover, behavior analysis has not adequately studied sexism and its subtle topographies despite sexism being a long-existing behavioral phenomenon. The purpose of the current paper is to provide a behavioral account of sexism, particularly in the field of behavior analysis. Feminism as a culture and views of feminism from males and females will be further examined, as well as their implications for behavior change. Finally, recommendations for cultural and individual change will be discussed to promote gender equity.

Identification of stable genes in the corpus luteum of lactating Holstein cows in pregnancy and luteolysis: Implications for selection of reverse-transcription quantitative PCR reference genes.

In lactating dairy cattle, the corpus luteum (CL) is a dynamic endocrine tissue vital for pregnancy maintenance, fertility, and cyclicity. Understanding processes underlying luteal physiology is therefore necessary to increase reproductive efficiency in cattle. A common technique for investigating luteal physiology is reverse-transcription quantitative PCR (RT-qPCR), a valuable tool for quantifying gene expression. However, reference-gene-based RT-qPCR quantification methods require utilization of stably expressed genes to accurately assess mRNA expression. Historically, selection of reference genes in cattle has relied on subjective selection of a small pool of reference genes, many of which may have significant expression variation among different tissues or physiologic states. This is particularly concerning in dynamic tissues such as the CL, with its capacity for rapid physiologic changes during luteolysis, and likely in the less characterized period of CL maintenance during pregnancy. Thus, there is a clear need to identify reference genes well suited for the bovine CL over a wide range of physiological states. Whole-transcriptome RNA sequencing stands as an effective method to identify new reference genes by enabling the assessment of the expression profile of the entire pool of mRNA transcripts. We report the identification of 13 novel putative reference genes using RNA sequencing in the bovine CL throughout early pregnancy and luteolysis: RPL4, UQCRFS1, COX4I1, RPS4X, SSR3, CST3, ZNF266, CDC42, CD63, HIF1A, YWHAE, EIF3E, and PPIB. Independent RT-qPCR analyses were conducted confirming expression stability in another set of CL tissues from pregnancy and regression, with analyses performed for 3 groups of samples: (1) all samples, (2) samples from pregnancy alone, and (3) samples throughout the process of CL regression. Seven genes were found to be more stable in all states than 2 traditional reference genes (ACTB and GAPDH): RPS4X, COX4I1, PPIB, SSR3, RPL4, YWHAE, and CDC42. When CL tissues from pregnant animals alone were analyzed, CST3, HIF1A, and CD63 were also identified as more stable than ACTB and GAPDH. Identification of these new reference genes will aid in accurate normalization of RT-qPCR results, contributing to proper interpretation of gene expression relevant to luteal physiology. Furthermore, our analysis sheds light on the effects of luteolysis and pregnancy on the stability of gene expression in the bovine CL.

Comparison of lameness outcomes in horses with acute or chronic digital lameness that underwent magnetic resonance imaging.

Aims: To compare the outcome, in terms of lameness score or return to athletic function, of horses with acute vs. chronic digital lameness that underwent magnetic resonance imaging (MRI) of the distal limb and to compare the proportion of horses that received intra-articular therapy of the distal interphalangeal (DIP) joint and pattern of diagnostic analgesia in these groups. Methods: This is a retrospective study of horses (n = 95) with acute (≤12 weeks; n = 46) or chronic (>12 weeks; n = 49) digital lameness that underwent MRI of the distal limb from 2009-2016, at two equine referral centres in the USA. Criteria for inclusion in the study were that a majority of lameness localised distal to the fetlock, and that lameness assessments for ≥12 months following MRI could be obtained from the medical record or the owner could be interviewed regarding their horse's athletic function. Outcome was characterised by an improvement score where 2 = return to work at a previous or higher level or lameness improved by one grade or more, 1 = return to work at a lower level or lameness improved by less than one grade, and 0 = did not return to work or lameness grade worsened. Whether horses had received intra-articular therapy of the DIP joint and the pattern of diagnostic analgesia prior to MRI was also obtained from medical records or by interviewing the owner. Results: There was a difference (p = 0.004) in the proportion of horses assigned to improvement scores of 0, 1 and 2 between horses with acute or chronic lameness. There was no evidence of a difference in the likelihood of having received intra-articular therapy of the DIP joint prior to MRI between horses with chronic or acute lameness (p = 0.085). Similarly, there was no evidence of a difference in the pattern of diagnostic analgesia prior to MRI between the two groups (p = 0.94). Eighty-two percent of owners of horses with acute and 62% of those with horses with chronic lameness had a positive opinion of the utility of MRI as a diagnostic modality. Conclusion: In a population of horses with digital lameness undergoing MRI, a difference in the outcome, in terms of lameness score or return to athletic function was identified between horses with acute lameness compared to those with chronic lameness. Clinical relevance: Horses with digital lameness that undergo MRI when the lameness is acute may have an improved prognosis due to accurate diagnosis and earlier application of appropriate therapy.

Effect of hyperbaric oxygen therapy and corticosteroid therapy in military personnel with acute acoustic trauma.

INTRODUCTION: Acute acoustic trauma (AAT) is a sensorineural hearing impairment due to exposure to an intense impulse noise which causes cochlear hypoxia. Hyperbaric oxygen therapy (HBO) could provide an adequate oxygen supply. The aim was to investigate the effectiveness of early treatment with combined HBO and corticosteroid therapy in patients with AAT compared with corticosteroid monotherapy. METHODS: A retrospective study was performed on military personnel diagnosed with AAT between November 2012 and December 2017. Inclusion criteria for HBO therapy were hearing loss of 30 dB or greater on at least one, 25 dB or more on at least two, or 20 dB or more on three or more frequencies as compared with the contralateral ear. RESULTS: Absolute hearing improvements showed significant differences (independent t-test) between patients receiving HBO and the control group at 500 Hz (p=0.014), 3000 Hz (p=0.023), 4000 Hz (p=0.001) and 6000 Hz (p=0.01) and at the mean of all frequencies (p=0.002). Relative hearing improvements were significantly different (independent t-test) at 4000 Hz (p=0.046) and 6000 Hz (p=0.013) and at all frequencies combined (p=0.005). Furthermore, the percentage of patients with recovery to the functional level required by the Dutch Armed Forces (clinical outcome score) was higher in the HBO group. CONCLUSIONS: Early-stage combination therapy for patients with AAT was associated with better audiometric results at higher frequencies and better clinical outcome score.

[Do the new molecular assays-microarray and realtime polymerase chain reaction-for dermatophyte detection keep what they promise?] / Halten die neuen molekularen Teste ­ Microarray und Realtime-Polymerasekettenreaktion ­ zum Dermatophytennachweis das, was sie versprechen?

In this study, a novel real-time polymerase chain reaction (PCR) assay (DermaGenius®2.0, PathoNostics BV, Maastricht, The Netherlands) and a recently developed microarray test (EUROArray Dermatomycosis, Euroimmun, Lübeck, Germany) were evaluated regarding their diagnostic specificity to identify dermatophyte DNA. The tests were compared to conventional methods and sequencing. The microarray Dermatomycosis test allows the detection of 50 dermatophytes and definitive identification of 23 dermatophyte species, 6 yeasts and moulds combined in one test. In comparison, real-time PCR is able to identify 11 dermatophytes and one yeast at the species level. Using the EUROArray, 22 out of 24 dermatophyte species were correctly identified. Using real-time PCR, 9 out of the 11 different dermatophytes included in the test kit were correctly identified. Both molecular tests for detection and differentiation of dermatophytes are useful tools for daily clinical practice. The real-time PCR test does not detect as many species, and specificity is slightly lower. However, real-time PCR is a very fast and easy to perform test, especially since no post-PCR step is necessary. Real-time PCR detects the most frequent dermatophytes like T. rubrum, T. interdigitale, and M. canis without any problems. The EUROArray is more elaborate to perform in the lab, due to the hybridization step. However, the EUROArray shows higher specificity and can detect a much broader range of causative agents, including rare species, in dermatomycology.

[Characteristic hindlimb lameness presentations in dogs]. / Gangbilder bei Lahmheiten der Hintergliedmasse des Hundes.

INTRODUCTION: Lameness in dogs are caused in about 70% of the cases in the hind limb, whereof about 50% are attributed to the knee joint. The current article shows selected lameness presentations on the basis of typical case studies. The lameness videos can be viewed via the corresponding QR code scanned with your mobile phones and tablets. Supplementary information on the diagnosis and therapy rounds off the cases.

INTRODUCTION: Lors de boiteries chez le chien, la couse est à chercher dans 70% des cas au niveau des postérieurs et pour 50% au niveau du genou. Sur la base de cas typiques choisis, on présente les images de la locomotion qui y sont associées. On peut, en scannant via le QR-Code correspondant sur une téléphone mobile ou une tablette, visualiser les films. Des informations sur la pose de diagnostic et le traitement complètent les cas.

[Tinea capitis and onychomycosis due to Trichophyton soudanense : Successful treatment with fluconazole-literature review]. / Tinea capitis und Onychomykose durch Trichophyton soudanense : Erfolgreiche Behandlung mit Fluconazol ­ Literaturübersicht.

Two African girls who moved to Germany only 4 weeks ago presented to the dermatological office with itchy and scaling skin lesions of the scalp and the thighs. The entire scalp of both girls was affected by a white, dry dandruff and a squamous crust. Dry centrifugal spreading erythematosquamous lesions were found on the thighs. The surface of the left thumbnail of the younger girl was whitish. The Blancophor® preparations which were performed under the suspicion of a tinea capitis et corporis and onychomycosis from skin scrapings of the scalp and the thighs, and from the thumbnail of the younger child were positive. Cultivation of three samples from the affected body sites-hair, skin and nail-revealed Trichophyton (T.) soudanense. For confirmation of the species identification, the isolates were subject of sequencing of ITS region of the rDNA and also of the translation elongation factor 1 α (TEF 1 α) gene. The phylogenetic analysis of the strains-the dendrogram of fungal strains-demonstrated the genetic differences between T. soudanense and T. rubrum. In contrast, sequencing of the TEF 1 α gene did not allow any discrimination between T. soudanense and T. rubrum. Both girls were treated orally with fluconazole. For topical treatment of both girls, ciclopirox olamine solution and terbinafine cream were administered, each once daily. After 8 weeks oral fluconazole therapy the dermatomycoses of skin, scalp, and thumbnail of both children were completely healed. Currently, in Germany and Europe, in immigrants from West African countries (e. g., from Angola) dermatophytoses due to T. soudanense have to be expected. Cultural identification of the pathogen is relatively simple. However, only molecular methods allow the exact discrimination of T. violaceum and T. rubrum.

[Hedgehog fungi in a dermatological office in Munich : Case reports and review]. / Igelpilze in einer Münchner Hautarztpraxis : Fallbeschreibungen und Übersicht.

Patient 1: After contact to a central European hedgehog (Erinaceus europaeus), a 50-year-old female with atopy developed erythrosquamous tinea manus on the thumb and thenar eminence of the right hand. The patient had previously been scalded by hot steam at the affected site. The zoophilic dermatophyte Trichophyton erinacei could be cultured from the hedgehog as well as from scrapings from the woman's skin. Antifungal treatment of the hedgehog was initiated using 2 weekly cycles of itraconazole solution (0.1 ml/kg body weight, BW). In addition, every other day enilconazole solution was used for topical treatment. The patient was treated with ciclopirox olamine cream and oral terbinafine 250 mg daily for 2 weeks, which led to healing of the Tinea manus .Patient 2: An 18-year-old woman presented for emergency consultation with rimmed, papulous, vesicular and erosive crusted skin lesions of the index finger, and an erythematous dry scaling round lesion on the thigh. The patient worked at an animal care facility, specifically caring for hedgehogs. One of the hedgehogs suffered from a substantial loss of spines. Fungal cultures from skin scrapings of both lesions yielded T. erinacei. Treatment with ciclopirox olamine cream and oral terbinafine 250 mg for 14 days was initiated which led to healing of the lesions. Identification of all three T. erinacei isolates from both patients and from the hedgehog was confirmed by sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA, and of the translation elongation factor (TEF)-1-alpha gene. Using ITS sequencing discrimination between T. erinacei strains from European and from African hedgehogs is possible. T. erinacei should be considered a so-called emerging pathogen. In Germany the zoophilic dermatophyte T. erinacei should be taken into account as causative agent of dermatomycoses in humans after contact to hedgehogs.

[Simple repair of Monteggia fractures in the cat]. / Einfache Methode zur Stabilisierung von Monteggia Frakturen bei der Katze.

INTRODUCTION: Monteggia fractures are rare traumatic injuries in cats and dogs. Ulna repair is mostly achieved by plates. Stable radial head fixation however is challenging. Temporary position screws have to be removed due to rotation forces in the elbow joint causing screw loosening. We present a novel and simple method using a sling technique, which holds the radial head in its physiological position and allows normal elbow movement.

[Tinea barbae profunda due to Trichophyton mentagrophytes after journey to Thailand : Case report and review]. / Tinea barbae profunda durch Trichophyton mentagrophytes nach Thailand-Reise : Fallbeschreibung und Übersicht.

Tinea barbae represents a very rare dermatophytosis. We report on a tinea barbae profunda following a journey to Southeast Asia. After travel to Thailand, a businessman was affected by a foudroyant proceeding abscessing infection of the upper lip and beard area. The initial therapy with oral acyclovir and oral ciprofloxacin, which later was changed to ampicillin plus sulbactam, intravenously, was unsuccessful. In a biopsy sample, histologically, with Grocott-Gomori's methenamine silver stain, fungal mycelium was apparent in the tissue. Thereupon, terbinafine 250 mg was given for 4 weeks, topically, a 1% ciclopiroxolamine-containing cream. In fungal culture, T. mentagrophytes were found to grow. Meanwhile, the patient's German wife suffered from a tinea faciei. From skin scrapings from the cheek, T. mentagrophytes was also cultivated. This zoophilic dermatophyte was identical with other zoophilic strains of T. mentagrophytes currently found in Germany, which were also acquired in Thailand. The patient had contact with Thai female sex workers who must be considered as a source of infection of the dermatophytosis. There was no animal contact, neither in Thailand, nor in Germany. The infection chain of the dermatophytosis from Thailand probably reached from a female sex worker via the here described patient to his wife in Germany. This pathway of infection has been known for 1 or 2 years, but until now, in Germany, Switzerland, and Austria exclusively via pubogenital infections (tinea genitalis profunda) due to T. mentagrophytes after journeys to Southeast Asia. For treatment, oral antifungal agents should be used, first of all terbinafine, alternatively fluconazole or itraconazole.

New insights on the antibacterial efficacy of miconazole in vitro.

Miconazole is a broad-spectrum antifungal used in topical preparations. In the present investigation the minimal inhibitory concentration (MIC) of miconazole for eighty wild type strains of gram-positive and gram-negative bacteria isolated from infected skin lesions was assessed using a modified agar dilution test (adapted to CLSI, Clinical Laboratory Standards Institute). 14 ATCC reference strains served as controls. Miconazole was found efficacious against gram-positive aerobic bacteria (n=62 species), the MICs against Staphylococcus (S.) aureus, S. spp., Streptococcus spp. und Enterococcus spp. ranged between 0.78 and 6.25 µg/mL. Interestingly, there were no differences in susceptibility between methicillin-susceptible (MSSA, 3) methicillin-resistant (MRSA, 6) and fusidic acid-resistant (FRSA, 2) S. aureus isolates. Strains of Streptococcus pyogenes (A-streptococci) (8) were found to be slightly more sensitive (0.78-1.563 µg/mL), while for gram-negative bacteria, no efficacy was found within the concentrations tested (MIC >200 µg/mL). In conclusion, for the gram-positive aerobic bacteria the MICs of miconazole were found within a range which is much lower than the concentration of miconazole used in topical preparations (2%). Thus topically applied miconazole might be a therapeutic option in skin infections especially caused by gram-positive bacteria even by those strains which are resistant to antibiotics.

Aggregation and a strong Allee effect in a cooperative outbreak insect.

Most species that are negatively impacted when their densities are low aggregate to minimize this effect. Aggregation has the potential to change how Allee effects are expressed at the population level. We studied the interplay between aggregation and Allee effects in the mountain pine beetle (Dendroctonus ponderosae Hopkins), an irruptive bark beetle that aggregates to overcome tree defenses. By cooperating to surpass a critical number of attacks per tree, the mountain pine beetle is able to breach host defenses, oviposit, and reproduce. Mountain pine beetles and Hymenopteran parasitoids share some biological features, the most notable of which is obligatory host death as a consequence of parasitoid attack and development. We developed spatiotemporal models of mountain pine beetle dynamics that were based on the Nicholson-Bailey framework but which featured beetle aggregation and a tree-level attack threshold. By fitting our models to data from a local mountain pine beetle outbreak, we demonstrate that due to aggregation, attack thresholds at the tree level can be overcome by a surprisingly low ratio of beetles per susceptible tree at the stand level. This results confirms the importance of considering aggregation in models of organisms that are subject to strong Allee effects.