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Objectives White piedra (WP) is a fungal infection that affects hair shafts, resulting in the formation of soft nodules that can be white, gray, or brown. While it was initially believed to be caused by Trichosporon beigelii , genetic analysis has reclassified Trichosporon inkin , T. ovoides , and T. cutaneum , as the primary causative agents of WP. In this report, we present a rare documented case of WP caused by Candida orthopsilosis , as a member of Candida parapsilosis complex, occurring without presence of Trichosporon in a temperate region in northern Iran. Case presentation A 3-year-old girl visited a dermatology clinic with complaints of hair knots in the occipital area, particularly around the ears, that were difficult to remove. These symptoms have persisted for two months. The patient has no history of gym classes or kindergarten attendance and was not taking any specific medications. No other areas of her body were affected, and none of her family members reported experiencing any symptoms. Fungal isolates were identified using PCR-RFLP and confirmed by sequencing. Antifungal susceptibility testing of the isolates was conducted based on CLSI M27-S3 guidelines. Conclusions We suggest that C. orthopsilosis can cause WP independently of Trichosporon species, particularly in temperate regions. Future studies should establish a clear relationship between the yeast responsible for WP and its geographic location. This case could increase awareness among dermatologists and laboratory physicians, emphasizing that the growth of Candida species should not be dismissed as contaminant.

Piedras are small nodules found on the hair shafts. White piedra was initially described as caused by Trichosporon beigelii, which was later reclassified in several species. We describe the first case of white piedra caused by Cutaneotrichosporon debeurmannianum. Affected hairs were examined in natura with scanning electron microscopy, after gold metallization. The typical whitish cerebriform creamy colony was obtained in Sabouraud medium. Fungal genomic DNA extracted from cultures and locus was amplified with the NL1/NL4 primer pair from the D1/D2 region of the large ribosomal subunit (LSU) of 28S rRNA. With scanning electron microscopy, nodules are easily identified surrounding the hair shaft; with high magnifications, rounded structures adhered to each other were identified. Comparison of the nucleotide sequences of IMT-1703 Cutaneotrichosporon debeurmannianum revealed 99.6% similarity with the 28S large ribosomal unit rDNA sequence. This case of white piedra was caused by Cutaneotrichosporon debeurmannianum.

White piedra is a superficial mycosis characterized by soft, white-to-tan, irregular nodules attached to the hair shafts. A 36-year-old man presented with small lumps in his pubic hair, without any other symptoms. The clinical features were suggestive of trichobacteriosis. Pathology analysis of the infected hair revealed that the concretions surrounding the hair shaft were full of fungal elements, parts of which had invaded into the cuticle. Culture on Sabouraud dextrose agar grew creamy, yellow–white colonies identified as Trichosporon inkin by the sequence of the nuclear ribosomal intergenic spacer region. The condition was treated by shaving the pubic hair and administering antifungal therapy (oral itraconazole and topical ketoconazole).

The ecosystem services framework has enabled the broader public to acknowledge the benefits nature provides to different stakeholders. However, not all stakeholders benefit equally from these services. Rather, power relationships are a key factor influencing the access of individuals or groups to ecosystem services. In this paper, we propose an adaptation of the \"cascade\" framework for ecosystem services to integrate the analysis of ecological interactions among ecosystem services and stakeholders' interactions, reflecting power relationships that mediate ecosystem services flows. We illustrate its application using the floodplain of the River Piedra (Spain) as a case study. First, we used structural equation modelling (SEM) to model the dependence relationships among ecosystem services. Second, we performed semi-structured interviews to identify formal power relationships among stakeholders. Third, we depicted ecosystem services according to stakeholders' ability to use, manage or impair ecosystem services in order to expose how power relationships mediate access to ecosystem services. Our results revealed that the strongest power was held by those stakeholders who managed (although did not use) those keystone ecosystem properties and services that determine the provision of other services (i.e., intermediate regulating and final services). In contrast, non-empowered stakeholders were only able to access the remaining non-excludable and non-rival ecosystem services (i.e., some of the cultural services, freshwater supply, water quality, and biological control). In addition, land stewardship, access rights, and governance appeared as critical factors determining the status of ecosystem services. Finally, we stress the need to analyse the role of stakeholders and their relationships to foster equal access to ecosystem services.

Superficial fungal infections arise from a pathogen that is restricted to the stratum corneum, with little or no tissue reaction. In this Seminar, three types of infection will be covered: tinea versicolor, piedra, and tinea nigra. Tinea versicolor is common worldwide and is caused by Malassezia spp, which are human saprophytes that sometimes switch from yeast to pathogenic mycelial form. Malassezia furfur, Malassezia globosa, and Malassezia sympodialis are most closely linked to tinea versicolor. White and black piedra are both common in tropical regions of the world; white piedra is also endemic in temperate climates. Black piedra is caused by Piedraia hortae; white piedra is due to pathogenic species of the Trichosporon genus. Tinea nigra is also common in tropical areas and has been confused with melanoma.

Drawing on theoretical understandings of the relationship between civil society and the state, the authors argue that the collapse of the kingdoms of Piedras Negras and Yaxchilan in the ninth century AD resulted from the same political processes that permitted the expansion of dynastic power in preceding centuries. Populations initially clustered around the dynastic capitals of these kingdoms, where daily spheres of interaction facilitated trust building among its residents. The image and performance of the polity was focused on the monarch, and participation in communal efforts, such as construction, warfare, and feasting, nurtured generalized trust within society as a whole, strengthening the polity. As populations expanded over the course of the Classic period and polities grew in territorial extent, spheres of interaction were more diffuse and trust-building efforts were increasingly focused on activities and individuals outside of the king and his court. The result was a breakdown of uniform trust across the kingdom and the failure of dynastic polities. Beyond a study of historical particularities in two kingdoms, this article is intended to suggest ways to more broadly frame interpretations of political processes in Maya polities within the broader context of ancient and modern complex societies worldwide. The model may also be applicable in other cultural contexts where emergent states contended with the challenges of maintaining coherency across an expanding territory.

We report four cases of scalp white piedra (SWP) in Brazilian female children. Morphological and physiological approaches gave inconsistent results for identifying Trichosporon to species level, while the sequencing of the intergenic spacer 1 region of ribosomal DNA accurately identified the agent of SWP as T. inkin. These cases emphasize the occurrence of this species causing this type of infection. The molecular identification of the suspected agent is needed for appropriate epidemiological surveillance of superficial mycoses caused by Trichosporon species.

Dispersal drives extinction-recolonization dynamics of metapopulations and is necessary for endangered species to recolonize former ranges. Yet few studies quantify dispersal and even fewer examine consistency of dispersal over many years. The northern elephant seal ( Mirounga angustirostris ) provides an example of the importance of dispersal. It quickly recolonized its full range after near extirpation by 19 th century hunting, and though dispersal was observed it was not quantified. Here we enumerate lifetime dispersal events among females marked as pups at two colonies during 1994-2010, then correct for detection biases to estimate bidirectional dispersal rates. An average of 16% of females born at the Piedras Blancas colony dispersed northward 200 km to breed at Año Nuevo, while 8.0% of those born at Año Nuevo dispersed southward to Piedras Blancas. The northward rate fluctuated considerably but was higher than southward in 15 of 17 cohorts. The population at Piedras Blancas expanded 15-fold during the study, while Año Nuevo’s declined slightly, but the expectation that seals would emigrate away from high density colonies was not supported. During the 1990s, dispersal was higher away from the small colony toward the large. Moreover, cohorts born later at Piedras Blancas, when the colony had grown, dispersed no more than early cohorts. Consistently high natal dispersal in northern elephant seals means the population must be considered a single large unit in terms of response to environmental change. High dispersal was fortuitous to the past recovery of the species, and continued dispersal means elephant seals will likely expand their range further.